llvm-6502/lib/Transforms/Scalar/PlaceSafepoints.cpp

989 lines
38 KiB
C++
Raw Permalink Normal View History

Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
//===- PlaceSafepoints.cpp - Place GC Safepoints --------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Place garbage collection safepoints at appropriate locations in the IR. This
// does not make relocation semantics or variable liveness explicit. That's
// done by RewriteStatepointsForGC.
//
// Terminology:
// - A call is said to be "parseable" if there is a stack map generated for the
// return PC of the call. A runtime can determine where values listed in the
// deopt arguments and (after RewriteStatepointsForGC) gc arguments are located
// on the stack when the code is suspended inside such a call. Every parse
// point is represented by a call wrapped in an gc.statepoint intrinsic.
// - A "poll" is an explicit check in the generated code to determine if the
// runtime needs the generated code to cooperate by calling a helper routine
// and thus suspending its execution at a known state. The call to the helper
// routine will be parseable. The (gc & runtime specific) logic of a poll is
// assumed to be provided in a function of the name "gc.safepoint_poll".
//
// We aim to insert polls such that running code can quickly be brought to a
// well defined state for inspection by the collector. In the current
// implementation, this is done via the insertion of poll sites at method entry
// and the backedge of most loops. We try to avoid inserting more polls than
// are neccessary to ensure a finite period between poll sites. This is not
// because the poll itself is expensive in the generated code; it's not. Polls
// do tend to impact the optimizer itself in negative ways; we'd like to avoid
// perturbing the optimization of the method as much as we can.
//
// We also need to make most call sites parseable. The callee might execute a
// poll (or otherwise be inspected by the GC). If so, the entire stack
// (including the suspended frame of the current method) must be parseable.
//
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// This pass will insert:
// - Call parse points ("call safepoints") for any call which may need to
// reach a safepoint during the execution of the callee function.
// - Backedge safepoint polls and entry safepoint polls to ensure that
// executing code reaches a safepoint poll in a finite amount of time.
//
// We do not currently support return statepoints, but adding them would not
// be hard. They are not required for correctness - entry safepoints are an
// alternative - but some GCs may prefer them. Patches welcome.
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
//
//===----------------------------------------------------------------------===//
#include "llvm/Pass.h"
#include "llvm/IR/LegacyPassManager.h"
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
#include "llvm/ADT/SetOperations.h"
#include "llvm/ADT/SetVector.h"
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringRef.h"
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
#include "llvm/Analysis/LoopPass.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
#include "llvm/Analysis/CFG.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InstIterator.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Statepoint.h"
#include "llvm/IR/Value.h"
#include "llvm/IR/Verifier.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/Local.h"
#define DEBUG_TYPE "safepoint-placement"
STATISTIC(NumEntrySafepoints, "Number of entry safepoints inserted");
STATISTIC(NumCallSafepoints, "Number of call safepoints inserted");
STATISTIC(NumBackedgeSafepoints, "Number of backedge safepoints inserted");
STATISTIC(CallInLoop, "Number of loops w/o safepoints due to calls in loop");
STATISTIC(FiniteExecution, "Number of loops w/o safepoints finite execution");
using namespace llvm;
// Ignore oppurtunities to avoid placing safepoints on backedges, useful for
// validation
static cl::opt<bool> AllBackedges("spp-all-backedges", cl::Hidden,
cl::init(false));
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
/// If true, do not place backedge safepoints in counted loops.
static cl::opt<bool> SkipCounted("spp-counted", cl::Hidden, cl::init(true));
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// If true, split the backedge of a loop when placing the safepoint, otherwise
// split the latch block itself. Both are useful to support for
// experimentation, but in practice, it looks like splitting the backedge
// optimizes better.
static cl::opt<bool> SplitBackedge("spp-split-backedge", cl::Hidden,
cl::init(false));
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// Print tracing output
static cl::opt<bool> TraceLSP("spp-trace", cl::Hidden, cl::init(false));
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
namespace {
/// An analysis pass whose purpose is to identify each of the backedges in
/// the function which require a safepoint poll to be inserted.
struct PlaceBackedgeSafepointsImpl : public FunctionPass {
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
static char ID;
/// The output of the pass - gives a list of each backedge (described by
/// pointing at the branch) which need a poll inserted.
std::vector<TerminatorInst *> PollLocations;
/// True unless we're running spp-no-calls in which case we need to disable
/// the call dependend placement opts.
bool CallSafepointsEnabled;
ScalarEvolution *SE = nullptr;
DominatorTree *DT = nullptr;
LoopInfo *LI = nullptr;
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
PlaceBackedgeSafepointsImpl(bool CallSafepoints = false)
: FunctionPass(ID), CallSafepointsEnabled(CallSafepoints) {
initializePlaceBackedgeSafepointsImplPass(*PassRegistry::getPassRegistry());
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
}
bool runOnLoop(Loop *);
void runOnLoopAndSubLoops(Loop *L) {
// Visit all the subloops
for (auto I = L->begin(), E = L->end(); I != E; I++)
runOnLoopAndSubLoops(*I);
runOnLoop(L);
}
bool runOnFunction(Function &F) override {
SE = &getAnalysis<ScalarEvolution>();
DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
for (auto I = LI->begin(), E = LI->end(); I != E; I++) {
runOnLoopAndSubLoops(*I);
}
return false;
}
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired<DominatorTreeWrapperPass>();
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
AU.addRequired<ScalarEvolution>();
AU.addRequired<LoopInfoWrapperPass>();
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// We no longer modify the IR at all in this pass. Thus all
// analysis are preserved.
AU.setPreservesAll();
}
};
}
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
static cl::opt<bool> NoEntry("spp-no-entry", cl::Hidden, cl::init(false));
static cl::opt<bool> NoCall("spp-no-call", cl::Hidden, cl::init(false));
static cl::opt<bool> NoBackedge("spp-no-backedge", cl::Hidden, cl::init(false));
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
namespace {
struct PlaceSafepoints : public FunctionPass {
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
static char ID; // Pass identification, replacement for typeid
PlaceSafepoints() : FunctionPass(ID) {
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
initializePlaceSafepointsPass(*PassRegistry::getPassRegistry());
}
bool runOnFunction(Function &F) override;
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
void getAnalysisUsage(AnalysisUsage &AU) const override {
// We modify the graph wholesale (inlining, block insertion, etc). We
// preserve nothing at the moment. We could potentially preserve dom tree
// if that was worth doing
}
};
}
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// Insert a safepoint poll immediately before the given instruction. Does
// not handle the parsability of state at the runtime call, that's the
// callers job.
static void
InsertSafepointPoll(Instruction *InsertBefore,
std::vector<CallSite> &ParsePointsNeeded /*rval*/);
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
static bool isGCLeafFunction(const CallSite &CS);
static bool needsStatepoint(const CallSite &CS) {
if (isGCLeafFunction(CS))
return false;
if (CS.isCall()) {
CallInst *call = cast<CallInst>(CS.getInstruction());
if (call->isInlineAsm())
return false;
}
if (isStatepoint(CS) || isGCRelocate(CS) || isGCResult(CS)) {
return false;
}
return true;
}
static Value *ReplaceWithStatepoint(const CallSite &CS, Pass *P);
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
/// Returns true if this loop is known to contain a call safepoint which
/// must unconditionally execute on any iteration of the loop which returns
/// to the loop header via an edge from Pred. Returns a conservative correct
/// answer; i.e. false is always valid.
static bool containsUnconditionalCallSafepoint(Loop *L, BasicBlock *Header,
BasicBlock *Pred,
DominatorTree &DT) {
// In general, we're looking for any cut of the graph which ensures
// there's a call safepoint along every edge between Header and Pred.
// For the moment, we look only for the 'cuts' that consist of a single call
// instruction in a block which is dominated by the Header and dominates the
// loop latch (Pred) block. Somewhat surprisingly, walking the entire chain
// of such dominating blocks gets substaintially more occurences than just
// checking the Pred and Header blocks themselves. This may be due to the
// density of loop exit conditions caused by range and null checks.
// TODO: structure this as an analysis pass, cache the result for subloops,
// avoid dom tree recalculations
assert(DT.dominates(Header, Pred) && "loop latch not dominated by header?");
BasicBlock *Current = Pred;
while (true) {
for (Instruction &I : *Current) {
if (auto CS = CallSite(&I))
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// Note: Technically, needing a safepoint isn't quite the right
// condition here. We should instead be checking if the target method
// has an
// unconditional poll. In practice, this is only a theoretical concern
// since we don't have any methods with conditional-only safepoint
// polls.
if (needsStatepoint(CS))
return true;
}
if (Current == Header)
break;
Current = DT.getNode(Current)->getIDom()->getBlock();
}
return false;
}
/// Returns true if this loop is known to terminate in a finite number of
/// iterations. Note that this function may return false for a loop which
/// does actual terminate in a finite constant number of iterations due to
/// conservatism in the analysis.
static bool mustBeFiniteCountedLoop(Loop *L, ScalarEvolution *SE,
BasicBlock *Pred) {
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// Only used when SkipCounted is off
const unsigned upperTripBound = 8192;
// A conservative bound on the loop as a whole.
const SCEV *MaxTrips = SE->getMaxBackedgeTakenCount(L);
if (MaxTrips != SE->getCouldNotCompute()) {
if (SE->getUnsignedRange(MaxTrips).getUnsignedMax().ult(upperTripBound))
return true;
if (SkipCounted &&
SE->getUnsignedRange(MaxTrips).getUnsignedMax().isIntN(32))
return true;
}
// If this is a conditional branch to the header with the alternate path
// being outside the loop, we can ask questions about the execution frequency
// of the exit block.
if (L->isLoopExiting(Pred)) {
// This returns an exact expression only. TODO: We really only need an
// upper bound here, but SE doesn't expose that.
const SCEV *MaxExec = SE->getExitCount(L, Pred);
if (MaxExec != SE->getCouldNotCompute()) {
if (SE->getUnsignedRange(MaxExec).getUnsignedMax().ult(upperTripBound))
return true;
if (SkipCounted &&
SE->getUnsignedRange(MaxExec).getUnsignedMax().isIntN(32))
return true;
}
}
return /* not finite */ false;
}
static void scanOneBB(Instruction *start, Instruction *end,
std::vector<CallInst *> &calls,
std::set<BasicBlock *> &seen,
std::vector<BasicBlock *> &worklist) {
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
for (BasicBlock::iterator itr(start);
itr != start->getParent()->end() && itr != BasicBlock::iterator(end);
itr++) {
if (CallInst *CI = dyn_cast<CallInst>(&*itr)) {
calls.push_back(CI);
}
// FIXME: This code does not handle invokes
assert(!dyn_cast<InvokeInst>(&*itr) &&
"support for invokes in poll code needed");
// Only add the successor blocks if we reach the terminator instruction
// without encountering end first
if (itr->isTerminator()) {
BasicBlock *BB = itr->getParent();
for (BasicBlock *Succ : successors(BB)) {
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
if (seen.count(Succ) == 0) {
worklist.push_back(Succ);
seen.insert(Succ);
}
}
}
}
}
static void scanInlinedCode(Instruction *start, Instruction *end,
std::vector<CallInst *> &calls,
std::set<BasicBlock *> &seen) {
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
calls.clear();
std::vector<BasicBlock *> worklist;
seen.insert(start->getParent());
scanOneBB(start, end, calls, seen, worklist);
while (!worklist.empty()) {
BasicBlock *BB = worklist.back();
worklist.pop_back();
scanOneBB(&*BB->begin(), end, calls, seen, worklist);
}
}
bool PlaceBackedgeSafepointsImpl::runOnLoop(Loop *L) {
// Loop through all loop latches (branches controlling backedges). We need
// to place a safepoint on every backedge (potentially).
// Note: In common usage, there will be only one edge due to LoopSimplify
// having run sometime earlier in the pipeline, but this code must be correct
// w.r.t. loops with multiple backedges.
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
BasicBlock *header = L->getHeader();
SmallVector<BasicBlock*, 16> LoopLatches;
L->getLoopLatches(LoopLatches);
for (BasicBlock *pred : LoopLatches) {
assert(L->contains(pred));
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// Make a policy decision about whether this loop needs a safepoint or
// not. Note that this is about unburdening the optimizer in loops, not
// avoiding the runtime cost of the actual safepoint.
if (!AllBackedges) {
if (mustBeFiniteCountedLoop(L, SE, pred)) {
if (TraceLSP)
errs() << "skipping safepoint placement in finite loop\n";
FiniteExecution++;
continue;
}
if (CallSafepointsEnabled &&
containsUnconditionalCallSafepoint(L, header, pred, *DT)) {
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// Note: This is only semantically legal since we won't do any further
// IPO or inlining before the actual call insertion.. If we hadn't, we
// might latter loose this call safepoint.
if (TraceLSP)
errs() << "skipping safepoint placement due to unconditional call\n";
CallInLoop++;
continue;
}
}
// TODO: We can create an inner loop which runs a finite number of
// iterations with an outer loop which contains a safepoint. This would
// not help runtime performance that much, but it might help our ability to
// optimize the inner loop.
// Safepoint insertion would involve creating a new basic block (as the
// target of the current backedge) which does the safepoint (of all live
// variables) and branches to the true header
TerminatorInst *term = pred->getTerminator();
if (TraceLSP) {
errs() << "[LSP] terminator instruction: ";
term->dump();
}
PollLocations.push_back(term);
}
return false;
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
}
/// Returns true if an entry safepoint is not required before this callsite in
/// the caller function.
static bool doesNotRequireEntrySafepointBefore(const CallSite &CS) {
Instruction *Inst = CS.getInstruction();
if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Inst)) {
switch (II->getIntrinsicID()) {
case Intrinsic::experimental_gc_statepoint:
case Intrinsic::experimental_patchpoint_void:
case Intrinsic::experimental_patchpoint_i64:
// The can wrap an actual call which may grow the stack by an unbounded
// amount or run forever.
return false;
default:
// Most LLVM intrinsics are things which do not expand to actual calls, or
// at least if they do, are leaf functions that cause only finite stack
// growth. In particular, the optimizer likes to form things like memsets
// out of stores in the original IR. Another important example is
// llvm.localescape which must occur in the entry block. Inserting a
// safepoint before it is not legal since it could push the localescape
// out of the entry block.
return true;
}
}
return false;
}
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
static Instruction *findLocationForEntrySafepoint(Function &F,
DominatorTree &DT) {
// Conceptually, this poll needs to be on method entry, but in
// practice, we place it as late in the entry block as possible. We
// can place it as late as we want as long as it dominates all calls
// that can grow the stack. This, combined with backedge polls,
// give us all the progress guarantees we need.
// hasNextInstruction and nextInstruction are used to iterate
// through a "straight line" execution sequence.
auto hasNextInstruction = [](Instruction *I) {
if (!I->isTerminator()) {
return true;
}
BasicBlock *nextBB = I->getParent()->getUniqueSuccessor();
return nextBB && (nextBB->getUniquePredecessor() != nullptr);
};
auto nextInstruction = [&hasNextInstruction](Instruction *I) {
assert(hasNextInstruction(I) &&
"first check if there is a next instruction!");
if (I->isTerminator()) {
return I->getParent()->getUniqueSuccessor()->begin();
} else {
return std::next(BasicBlock::iterator(I));
}
};
Instruction *cursor = nullptr;
for (cursor = F.getEntryBlock().begin(); hasNextInstruction(cursor);
cursor = nextInstruction(cursor)) {
// We need to ensure a safepoint poll occurs before any 'real' call. The
// easiest way to ensure finite execution between safepoints in the face of
// recursive and mutually recursive functions is to enforce that each take
// a safepoint. Additionally, we need to ensure a poll before any call
// which can grow the stack by an unbounded amount. This isn't required
// for GC semantics per se, but is a common requirement for languages
// which detect stack overflow via guard pages and then throw exceptions.
if (auto CS = CallSite(cursor)) {
if (doesNotRequireEntrySafepointBefore(CS))
continue;
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
break;
}
}
assert((hasNextInstruction(cursor) || cursor->isTerminator()) &&
"either we stopped because of a call, or because of terminator");
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
return cursor;
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
}
/// Identify the list of call sites which need to be have parseable state
static void findCallSafepoints(Function &F,
std::vector<CallSite> &Found /*rval*/) {
assert(Found.empty() && "must be empty!");
for (Instruction &I : inst_range(F)) {
Instruction *inst = &I;
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
if (isa<CallInst>(inst) || isa<InvokeInst>(inst)) {
CallSite CS(inst);
// No safepoint needed or wanted
if (!needsStatepoint(CS)) {
continue;
}
Found.push_back(CS);
}
}
}
/// Implement a unique function which doesn't require we sort the input
/// vector. Doing so has the effect of changing the output of a couple of
/// tests in ways which make them less useful in testing fused safepoints.
template <typename T> static void unique_unsorted(std::vector<T> &vec) {
std::set<T> seen;
std::vector<T> tmp;
vec.reserve(vec.size());
std::swap(tmp, vec);
for (auto V : tmp) {
if (seen.insert(V).second) {
vec.push_back(V);
}
}
}
static const char *const GCSafepointPollName = "gc.safepoint_poll";
static bool isGCSafepointPoll(Function &F) {
return F.getName().equals(GCSafepointPollName);
}
/// Returns true if this function should be rewritten to include safepoint
/// polls and parseable call sites. The main point of this function is to be
/// an extension point for custom logic.
static bool shouldRewriteFunction(Function &F) {
// TODO: This should check the GCStrategy
if (F.hasGC()) {
const char *FunctionGCName = F.getGC();
const StringRef StatepointExampleName("statepoint-example");
const StringRef CoreCLRName("coreclr");
return (StatepointExampleName == FunctionGCName) ||
(CoreCLRName == FunctionGCName);
} else
return false;
}
// TODO: These should become properties of the GCStrategy, possibly with
// command line overrides.
static bool enableEntrySafepoints(Function &F) { return !NoEntry; }
static bool enableBackedgeSafepoints(Function &F) { return !NoBackedge; }
static bool enableCallSafepoints(Function &F) { return !NoCall; }
// Normalize basic block to make it ready to be target of invoke statepoint.
// Ensure that 'BB' does not have phi nodes. It may require spliting it.
static BasicBlock *normalizeForInvokeSafepoint(BasicBlock *BB,
BasicBlock *InvokeParent) {
BasicBlock *ret = BB;
if (!BB->getUniquePredecessor()) {
ret = SplitBlockPredecessors(BB, InvokeParent, "");
}
// Now that 'ret' has unique predecessor we can safely remove all phi nodes
// from it
FoldSingleEntryPHINodes(ret);
assert(!isa<PHINode>(ret->begin()));
return ret;
}
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
bool PlaceSafepoints::runOnFunction(Function &F) {
if (F.isDeclaration() || F.empty()) {
// This is a declaration, nothing to do. Must exit early to avoid crash in
// dom tree calculation
return false;
}
if (isGCSafepointPoll(F)) {
// Given we're inlining this inside of safepoint poll insertion, this
// doesn't make any sense. Note that we do make any contained calls
// parseable after we inline a poll.
return false;
}
if (!shouldRewriteFunction(F))
return false;
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
bool modified = false;
// In various bits below, we rely on the fact that uses are reachable from
// defs. When there are basic blocks unreachable from the entry, dominance
// and reachablity queries return non-sensical results. Thus, we preprocess
// the function to ensure these properties hold.
modified |= removeUnreachableBlocks(F);
// STEP 1 - Insert the safepoint polling locations. We do not need to
// actually insert parse points yet. That will be done for all polls and
// calls in a single pass.
DominatorTree DT;
DT.recalculate(F);
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
SmallVector<Instruction *, 16> PollsNeeded;
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
std::vector<CallSite> ParsePointNeeded;
if (enableBackedgeSafepoints(F)) {
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// Construct a pass manager to run the LoopPass backedge logic. We
// need the pass manager to handle scheduling all the loop passes
// appropriately. Doing this by hand is painful and just not worth messing
// with for the moment.
legacy::FunctionPassManager FPM(F.getParent());
bool CanAssumeCallSafepoints = enableCallSafepoints(F);
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
PlaceBackedgeSafepointsImpl *PBS =
new PlaceBackedgeSafepointsImpl(CanAssumeCallSafepoints);
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
FPM.add(PBS);
FPM.run(F);
// We preserve dominance information when inserting the poll, otherwise
// we'd have to recalculate this on every insert
DT.recalculate(F);
auto &PollLocations = PBS->PollLocations;
auto OrderByBBName = [](Instruction *a, Instruction *b) {
return a->getParent()->getName() < b->getParent()->getName();
};
// We need the order of list to be stable so that naming ends up stable
// when we split edges. This makes test cases much easier to write.
std::sort(PollLocations.begin(), PollLocations.end(), OrderByBBName);
// We can sometimes end up with duplicate poll locations. This happens if
// a single loop is visited more than once. The fact this happens seems
// wrong, but it does happen for the split-backedge.ll test case.
PollLocations.erase(std::unique(PollLocations.begin(),
PollLocations.end()),
PollLocations.end());
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// Insert a poll at each point the analysis pass identified
// The poll location must be the terminator of a loop latch block.
for (TerminatorInst *Term : PollLocations) {
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// We are inserting a poll, the function is modified
modified = true;
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
if (SplitBackedge) {
// Split the backedge of the loop and insert the poll within that new
// basic block. This creates a loop with two latches per original
// latch (which is non-ideal), but this appears to be easier to
// optimize in practice than inserting the poll immediately before the
// latch test.
// Since this is a latch, at least one of the successors must dominate
// it. Its possible that we have a) duplicate edges to the same header
// and b) edges to distinct loop headers. We need to insert pools on
// each.
SetVector<BasicBlock *> Headers;
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
for (unsigned i = 0; i < Term->getNumSuccessors(); i++) {
BasicBlock *Succ = Term->getSuccessor(i);
if (DT.dominates(Succ, Term->getParent())) {
Headers.insert(Succ);
}
}
assert(!Headers.empty() && "poll location is not a loop latch?");
// The split loop structure here is so that we only need to recalculate
// the dominator tree once. Alternatively, we could just keep it up to
// date and use a more natural merged loop.
SetVector<BasicBlock *> SplitBackedges;
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
for (BasicBlock *Header : Headers) {
BasicBlock *NewBB = SplitEdge(Term->getParent(), Header, &DT);
PollsNeeded.push_back(NewBB->getTerminator());
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
NumBackedgeSafepoints++;
}
} else {
// Split the latch block itself, right before the terminator.
PollsNeeded.push_back(Term);
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
NumBackedgeSafepoints++;
}
}
}
if (enableEntrySafepoints(F)) {
Instruction *Location = findLocationForEntrySafepoint(F, DT);
if (!Location) {
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// policy choice not to insert?
} else {
PollsNeeded.push_back(Location);
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
modified = true;
NumEntrySafepoints++;
}
}
// Now that we've identified all the needed safepoint poll locations, insert
// safepoint polls themselves.
for (Instruction *PollLocation : PollsNeeded) {
std::vector<CallSite> RuntimeCalls;
InsertSafepointPoll(PollLocation, RuntimeCalls);
ParsePointNeeded.insert(ParsePointNeeded.end(), RuntimeCalls.begin(),
RuntimeCalls.end());
}
PollsNeeded.clear(); // make sure we don't accidentally use
// The dominator tree has been invalidated by the inlining performed in the
// above loop. TODO: Teach the inliner how to update the dom tree?
DT.recalculate(F);
if (enableCallSafepoints(F)) {
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
std::vector<CallSite> Calls;
findCallSafepoints(F, Calls);
NumCallSafepoints += Calls.size();
ParsePointNeeded.insert(ParsePointNeeded.end(), Calls.begin(), Calls.end());
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
}
// Unique the vectors since we can end up with duplicates if we scan the call
// site for call safepoints after we add it for entry or backedge. The
// only reason we need tracking at all is that some functions might have
// polls but not call safepoints and thus we might miss marking the runtime
// calls for the polls. (This is useful in test cases!)
unique_unsorted(ParsePointNeeded);
// Any parse point (no matter what source) will be handled here
// We're about to start modifying the function
if (!ParsePointNeeded.empty())
modified = true;
// Now run through and insert the safepoints, but do _NOT_ update or remove
// any existing uses. We have references to live variables that need to
// survive to the last iteration of this loop.
std::vector<Value *> Results;
Results.reserve(ParsePointNeeded.size());
for (size_t i = 0; i < ParsePointNeeded.size(); i++) {
CallSite &CS = ParsePointNeeded[i];
// For invoke statepoints we need to remove all phi nodes at the normal
// destination block.
// Reason for this is that we can place gc_result only after last phi node
// in basic block. We will get malformed code after RAUW for the
// gc_result if one of this phi nodes uses result from the invoke.
if (InvokeInst *Invoke = dyn_cast<InvokeInst>(CS.getInstruction())) {
normalizeForInvokeSafepoint(Invoke->getNormalDest(),
Invoke->getParent());
}
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
Value *GCResult = ReplaceWithStatepoint(CS, nullptr);
Results.push_back(GCResult);
}
assert(Results.size() == ParsePointNeeded.size());
// Adjust all users of the old call sites to use the new ones instead
for (size_t i = 0; i < ParsePointNeeded.size(); i++) {
CallSite &CS = ParsePointNeeded[i];
Value *GCResult = Results[i];
if (GCResult) {
// Can not RAUW for the invoke gc result in case of phi nodes preset.
assert(CS.isCall() || !isa<PHINode>(cast<Instruction>(GCResult)->getParent()->begin()));
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// Replace all uses with the new call
CS.getInstruction()->replaceAllUsesWith(GCResult);
}
// Now that we've handled all uses, remove the original call itself
// Note: The insert point can't be the deleted instruction!
CS.getInstruction()->eraseFromParent();
}
return modified;
}
char PlaceBackedgeSafepointsImpl::ID = 0;
char PlaceSafepoints::ID = 0;
FunctionPass *llvm::createPlaceSafepointsPass() {
return new PlaceSafepoints();
}
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
INITIALIZE_PASS_BEGIN(PlaceBackedgeSafepointsImpl,
"place-backedge-safepoints-impl",
"Place Backedge Safepoints", false, false)
INITIALIZE_PASS_DEPENDENCY(ScalarEvolution)
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
INITIALIZE_PASS_END(PlaceBackedgeSafepointsImpl,
"place-backedge-safepoints-impl",
"Place Backedge Safepoints", false, false)
INITIALIZE_PASS_BEGIN(PlaceSafepoints, "place-safepoints", "Place Safepoints",
false, false)
INITIALIZE_PASS_END(PlaceSafepoints, "place-safepoints", "Place Safepoints",
false, false)
static bool isGCLeafFunction(const CallSite &CS) {
Instruction *inst = CS.getInstruction();
if (isa<IntrinsicInst>(inst)) {
// Most LLVM intrinsics are things which can never take a safepoint.
// As a result, we don't need to have the stack parsable at the
// callsite. This is a highly useful optimization since intrinsic
// calls are fairly prevelent, particularly in debug builds.
return true;
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
}
// If this function is marked explicitly as a leaf call, we don't need to
// place a safepoint of it. In fact, for correctness we *can't* in many
// cases. Note: Indirect calls return Null for the called function,
// these obviously aren't runtime functions with attributes
// TODO: Support attributes on the call site as well.
const Function *F = CS.getCalledFunction();
bool isLeaf =
F &&
F->getFnAttribute("gc-leaf-function").getValueAsString().equals("true");
if (isLeaf) {
return true;
}
return false;
}
static void
InsertSafepointPoll(Instruction *InsertBefore,
std::vector<CallSite> &ParsePointsNeeded /*rval*/) {
BasicBlock *OrigBB = InsertBefore->getParent();
Module *M = InsertBefore->getModule();
assert(M && "must be part of a module");
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// Inline the safepoint poll implementation - this will get all the branch,
// control flow, etc.. Most importantly, it will introduce the actual slow
// path call - where we need to insert a safepoint (parsepoint).
auto *F = M->getFunction(GCSafepointPollName);
assert(F->getType()->getElementType() ==
FunctionType::get(Type::getVoidTy(M->getContext()), false) &&
"gc.safepoint_poll declared with wrong type");
assert(!F->empty() && "gc.safepoint_poll must be a non-empty function");
CallInst *PollCall = CallInst::Create(F, "", InsertBefore);
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// Record some information about the call site we're replacing
BasicBlock::iterator before(PollCall), after(PollCall);
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
bool isBegin(false);
if (before == OrigBB->begin()) {
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
isBegin = true;
} else {
before--;
}
after++;
assert(after != OrigBB->end() && "must have successor");
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// do the actual inlining
InlineFunctionInfo IFI;
bool InlineStatus = InlineFunction(PollCall, IFI);
assert(InlineStatus && "inline must succeed");
(void)InlineStatus; // suppress warning in release-asserts
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// Check post conditions
assert(IFI.StaticAllocas.empty() && "can't have allocs");
std::vector<CallInst *> calls; // new calls
std::set<BasicBlock *> BBs; // new BBs + insertee
// Include only the newly inserted instructions, Note: begin may not be valid
// if we inserted to the beginning of the basic block
BasicBlock::iterator start;
if (isBegin) {
start = OrigBB->begin();
} else {
start = before;
start++;
}
// If your poll function includes an unreachable at the end, that's not
// valid. Bugpoint likes to create this, so check for it.
assert(isPotentiallyReachable(&*start, &*after, nullptr, nullptr) &&
"malformed poll function");
scanInlinedCode(&*(start), &*(after), calls, BBs);
assert(!calls.empty() && "slow path not found for safepoint poll");
// Record the fact we need a parsable state at the runtime call contained in
// the poll function. This is required so that the runtime knows how to
// parse the last frame when we actually take the safepoint (i.e. execute
// the slow path)
assert(ParsePointsNeeded.empty());
for (size_t i = 0; i < calls.size(); i++) {
// No safepoint needed or wanted
if (!needsStatepoint(calls[i])) {
continue;
}
// These are likely runtime calls. Should we assert that via calling
// convention or something?
ParsePointsNeeded.push_back(CallSite(calls[i]));
}
assert(ParsePointsNeeded.size() <= calls.size());
}
/// Replaces the given call site (Call or Invoke) with a gc.statepoint
/// intrinsic with an empty deoptimization arguments list. This does
/// NOT do explicit relocation for GC support.
static Value *ReplaceWithStatepoint(const CallSite &CS, /* to replace */
Pass *P) {
assert(CS.getInstruction()->getParent()->getParent()->getParent() &&
"must be set");
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// TODO: technically, a pass is not allowed to get functions from within a
// function pass since it might trigger a new function addition. Refactor
// this logic out to the initialization of the pass. Doesn't appear to
// matter in practice.
// Then go ahead and use the builder do actually do the inserts. We insert
// immediately before the previous instruction under the assumption that all
// arguments will be available here. We can't insert afterwards since we may
// be replacing a terminator.
IRBuilder<> Builder(CS.getInstruction());
// Note: The gc args are not filled in at this time, that's handled by
// RewriteStatepointsForGC (which is currently under review).
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// Create the statepoint given all the arguments
Instruction *Token = nullptr;
uint64_t ID;
uint32_t NumPatchBytes;
AttributeSet OriginalAttrs = CS.getAttributes();
Attribute AttrID =
OriginalAttrs.getAttribute(AttributeSet::FunctionIndex, "statepoint-id");
Attribute AttrNumPatchBytes = OriginalAttrs.getAttribute(
AttributeSet::FunctionIndex, "statepoint-num-patch-bytes");
AttrBuilder AttrsToRemove;
bool HasID = AttrID.isStringAttribute() &&
!AttrID.getValueAsString().getAsInteger(10, ID);
if (HasID)
AttrsToRemove.addAttribute("statepoint-id");
else
ID = 0xABCDEF00;
bool HasNumPatchBytes =
AttrNumPatchBytes.isStringAttribute() &&
!AttrNumPatchBytes.getValueAsString().getAsInteger(10, NumPatchBytes);
if (HasNumPatchBytes)
AttrsToRemove.addAttribute("statepoint-num-patch-bytes");
else
NumPatchBytes = 0;
OriginalAttrs = OriginalAttrs.removeAttributes(
CS.getInstruction()->getContext(), AttributeSet::FunctionIndex,
AttrsToRemove);
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
if (CS.isCall()) {
CallInst *ToReplace = cast<CallInst>(CS.getInstruction());
CallInst *Call = Builder.CreateGCStatepointCall(
ID, NumPatchBytes, CS.getCalledValue(),
makeArrayRef(CS.arg_begin(), CS.arg_end()), None, None,
"safepoint_token");
Call->setTailCall(ToReplace->isTailCall());
Call->setCallingConv(ToReplace->getCallingConv());
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// In case if we can handle this set of attributes - set up function
// attributes directly on statepoint and return attributes later for
// gc_result intrinsic.
Call->setAttributes(OriginalAttrs.getFnAttributes());
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
Token = Call;
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// Put the following gc_result and gc_relocate calls immediately after the
// the old call (which we're about to delete).
assert(ToReplace->getNextNode() && "not a terminator, must have next");
Builder.SetInsertPoint(ToReplace->getNextNode());
Builder.SetCurrentDebugLocation(ToReplace->getNextNode()->getDebugLoc());
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
} else if (CS.isInvoke()) {
InvokeInst *ToReplace = cast<InvokeInst>(CS.getInstruction());
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// Insert the new invoke into the old block. We'll remove the old one in a
// moment at which point this will become the new terminator for the
// original block.
Builder.SetInsertPoint(ToReplace->getParent());
InvokeInst *Invoke = Builder.CreateGCStatepointInvoke(
ID, NumPatchBytes, CS.getCalledValue(), ToReplace->getNormalDest(),
ToReplace->getUnwindDest(), makeArrayRef(CS.arg_begin(), CS.arg_end()),
None, None, "safepoint_token");
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
Invoke->setCallingConv(ToReplace->getCallingConv());
// In case if we can handle this set of attributes - set up function
// attributes directly on statepoint and return attributes later for
// gc_result intrinsic.
Invoke->setAttributes(OriginalAttrs.getFnAttributes());
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
Token = Invoke;
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// We'll insert the gc.result into the normal block
BasicBlock *NormalDest = ToReplace->getNormalDest();
// Can not insert gc.result in case of phi nodes preset.
// Should have removed this cases prior to runnning this function
assert(!isa<PHINode>(NormalDest->begin()));
Instruction *IP = &*(NormalDest->getFirstInsertionPt());
Builder.SetInsertPoint(IP);
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
} else {
llvm_unreachable("unexpect type of CallSite");
}
assert(Token);
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
// Handle the return value of the original call - update all uses to use a
// gc_result hanging off the statepoint node we just inserted
// Only add the gc_result iff there is actually a used result
if (!CS.getType()->isVoidTy() && !CS.getInstruction()->use_empty()) {
std::string TakenName =
CS.getInstruction()->hasName() ? CS.getInstruction()->getName() : "";
CallInst *GCResult = Builder.CreateGCResult(Token, CS.getType(), TakenName);
GCResult->setAttributes(OriginalAttrs.getRetAttributes());
return GCResult;
Add a pass for inserting safepoints into (nearly) arbitrary IR This pass is responsible for figuring out where to place call safepoints and safepoint polls. It doesn't actually make the relocations explicit; that's the job of the RewriteStatepointsForGC pass (http://reviews.llvm.org/D6975). Note that this code is not yet finalized. Its moving in tree for incremental development, but further cleanup is needed and will happen over the next few days. It is not yet part of the standard pass order. Planned changes in the near future: - I plan on restructuring the statepoint rewrite to use the functions add to the IRBuilder a while back. - In the current pass, the function "gc.safepoint_poll" is treated specially but is not an intrinsic. I plan to make identifying the poll function a property of the GCStrategy at some point in the near future. - As follow on patches, I will be separating a collection of test cases we have out of tree and submitting them upstream. - It's not explicit in the code, but these two patches are introducing a new state for a statepoint which looks a lot like a patchpoint. There's no a transient form which doesn't yet have the relocations explicitly represented, but does prevent reordering of memory operations. Once this is in, I need to update actually make this explicit by reserving the 'unused' argument of the statepoint as a flag, updating the docs, and making the code explicitly check for such a thing. This wasn't really planned, but once I split the two passes - which was done for other reasons - the intermediate state fell out. Just reminds us once again that we need to merge statepoints and patchpoints at some point in the not that distant future. Future directions planned: - Identifying more cases where a backedge safepoint isn't required to ensure timely execution of a safepoint poll. - Tweaking the insertion process to generate easier to optimize IR. (For example, investigating making SplitBackedge) the default. - Adding opt-in flags for a GCStrategy to use this pass. Once done, add this pass to the actual pass ordering. Differential Revision: http://reviews.llvm.org/D6981 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228090 91177308-0d34-0410-b5e6-96231b3b80d8
2015-02-04 00:37:33 +00:00
} else {
// No return value for the call.
return nullptr;
}
}