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https://github.com/c64scene-ar/llvm-6502.git
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Heavily refactor code:
* Separate the policy decisions into a derived class [InlineSimple]
* Move the inlining mechanics into a base class [Inliner]
* Change the inliner to be an SCCPass, making it more structured and
eventually pipelinable with other SCC passes
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@8257 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
parent
fa7f524162
commit
237ef567f6
@ -1,77 +1,47 @@
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//===- FunctionInlining.cpp - Code to perform function inlining -----------===//
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//===- InlineSimple.cpp - Code to perform simple function inlining --------===//
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//
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// This file implements bottom-up inlining of functions into callees.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "inline"
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#include "llvm/Transforms/IPO.h"
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#include "llvm/Module.h"
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#include "llvm/Pass.h"
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#include "llvm/iOther.h"
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#include "Inliner.h"
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#include "llvm/Function.h"
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#include "llvm/iMemory.h"
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#include "llvm/iTerminators.h"
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#include "llvm/Support/CallSite.h"
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#include "llvm/Transforms/Utils/Cloning.h"
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#include "Support/CommandLine.h"
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#include "Support/Debug.h"
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#include "Support/Statistic.h"
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#include <set>
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#include "llvm/Transforms/IPO.h"
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namespace {
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Statistic<> NumInlined("inline", "Number of functions inlined");
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Statistic<> NumDeleted("inline", "Number of functions deleted because all callers found");
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cl::opt<unsigned> // FIXME: 200 is VERY conservative
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InlineLimit("inline-threshold", cl::Hidden, cl::init(200),
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cl::desc("Control the amount of inlining to perform (default = 200)"));
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struct FunctionInlining : public Pass {
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virtual bool run(Module &M) {
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bool Changed = false;
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for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
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Changed |= doInlining(I);
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ProcessedFunctions.clear();
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return Changed;
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}
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private:
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std::set<Function*> ProcessedFunctions; // Prevent infinite recursion
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bool doInlining(Function *F);
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struct SimpleInliner : public Inliner {
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int getInlineCost(CallSite CS);
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};
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RegisterOpt<FunctionInlining> X("inline", "Function Integration/Inlining");
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RegisterOpt<SimpleInliner> X("inline", "Function Integration/Inlining");
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}
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Pass *createFunctionInliningPass() { return new FunctionInlining(); }
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Pass *createFunctionInliningPass() { return new SimpleInliner(); }
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// ShouldInlineFunction - The heuristic used to determine if we should inline
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// the function call or not.
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// getInlineCost - The heuristic used to determine if we should inline the
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// function call or not.
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//
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static inline bool ShouldInlineFunction(CallSite CS) {
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int SimpleInliner::getInlineCost(CallSite CS) {
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Instruction *TheCall = CS.getInstruction();
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assert(TheCall->getParent() && TheCall->getParent()->getParent() &&
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"Call not embedded into a function!");
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const Function *Callee = CS.getCalledFunction();
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if (Callee == 0 || Callee->isExternal())
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return false; // Cannot inline an indirect call... or external function.
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// Don't inline a recursive call.
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const Function *Caller = TheCall->getParent()->getParent();
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if (Caller == Callee) return false;
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// InlineQuality - This value measures how good of an inline candidate this
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// call site is to inline. The initial value determines how aggressive the
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// inliner is. If this value is negative after the final computation,
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// inlining is not performed.
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// Don't inline a directly recursive call.
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if (Caller == Callee) return 2000000000;
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// InlineCost - This value measures how good of an inline candidate this call
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// site is to inline. A lower inline cost make is more likely for the call to
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// be inlined. This value may go negative.
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//
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int InlineQuality = InlineLimit;
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int InlineCost = 0;
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// If there is only one call of the function, and it has internal linkage,
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// make it almost guaranteed to be inlined.
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//
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if (Callee->use_size() == 1 && Callee->hasInternalLinkage())
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InlineQuality += 30000;
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InlineCost -= 30000;
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// Add to the inline quality for properties that make the call valueable to
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// inline. This includes factors that indicate that the result of inlining
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@ -83,12 +53,12 @@ static inline bool ShouldInlineFunction(CallSite CS) {
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// Each argument passed in has a cost at both the caller and the callee
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// sides. This favors functions that take many arguments over functions
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// that take few arguments.
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InlineQuality += 20;
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InlineCost -= 20;
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// If this is a function being passed in, it is very likely that we will be
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// able to turn an indirect function call into a direct function call.
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if (isa<Function>(I))
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InlineQuality += 100;
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InlineCost -= 100;
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// If a constant, global variable or alloca is passed in, inlining this
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// function is likely to allow significant future optimization possibilities
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@ -96,7 +66,7 @@ static inline bool ShouldInlineFunction(CallSite CS) {
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// the inlining of the function.
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//
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else if (isa<Constant>(I) || isa<GlobalVariable>(I) || isa<AllocaInst>(I))
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InlineQuality += 60;
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InlineCost -= 60;
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}
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// Now that we have considered all of the factors that make the call site more
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@ -106,84 +76,14 @@ static inline bool ShouldInlineFunction(CallSite CS) {
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// Look at the size of the callee. Each basic block counts as 20 units, and
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// each instruction counts as 10.
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for (Function::const_iterator BB = Callee->begin(), E = Callee->end();
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BB != E; ++BB) {
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InlineQuality -= BB->size()*10 + 20;
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if (InlineQuality < 0) return false;
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}
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BB != E; ++BB)
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InlineCost += BB->size()*10 + 20;
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// Don't inline into something too big, which would make it bigger. Here, we
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// count each basic block as a single unit.
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for (Function::const_iterator BB = Caller->begin(), E = Caller->end();
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BB != E; ++BB) {
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--InlineQuality;
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if (InlineQuality < 0) return false;
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}
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BB != E; ++BB)
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InlineCost++;
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// If we get here, this call site is high enough "quality" to inline.
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DEBUG(std::cerr << "Inlining in '" << Caller->getName()
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<< "', quality = " << InlineQuality << ": " << *TheCall);
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return true;
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return InlineCost;
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}
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// doInlining - Use a heuristic based approach to inline functions that seem to
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// look good.
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//
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bool FunctionInlining::doInlining(Function *F) {
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// If we have already processed this function (ie, it is recursive) don't
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// revisit.
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std::set<Function*>::iterator PFI = ProcessedFunctions.lower_bound(F);
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if (PFI != ProcessedFunctions.end() && *PFI == F) return false;
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// Insert the function in the set so it doesn't get revisited.
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ProcessedFunctions.insert(PFI, F);
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bool Changed = false;
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for (Function::iterator BB = F->begin(); BB != F->end(); ++BB)
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for (BasicBlock::iterator I = BB->begin(); I != BB->end(); ) {
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bool ShouldInc = true;
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// Found a call or invoke instruction?
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if (isa<CallInst>(I) || isa<InvokeInst>(I)) {
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CallSite CS = CallSite::get(I);
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if (Function *Callee = CS.getCalledFunction()) {
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doInlining(Callee); // Inline in callees before callers!
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// Decide whether we should inline this function...
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if (ShouldInlineFunction(CS)) {
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// Save an iterator to the instruction before the call if it exists,
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// otherwise get an iterator at the end of the block... because the
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// call will be destroyed.
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//
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BasicBlock::iterator SI;
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if (I != BB->begin()) {
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SI = I; --SI; // Instruction before the call...
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} else {
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SI = BB->end();
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}
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// Attempt to inline the function...
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if (InlineFunction(CS)) {
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++NumInlined;
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Changed = true;
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// Move to instruction before the call...
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I = (SI == BB->end()) ? BB->begin() : SI;
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ShouldInc = false; // Don't increment iterator until next time
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// If we inlined the last possible call site to the function,
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// delete the function body now.
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if (Callee->use_empty() &&
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(Callee->hasInternalLinkage()||Callee->hasLinkOnceLinkage())){
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F->getParent()->getFunctionList().erase(Callee);
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++NumDeleted;
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if (Callee == F) return true;
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}
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}
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}
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}
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}
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if (ShouldInc) ++I;
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}
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return Changed;
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}
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119
lib/Transforms/IPO/Inliner.cpp
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119
lib/Transforms/IPO/Inliner.cpp
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@ -0,0 +1,119 @@
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//===- InlineCommon.cpp - Code common to all inliners ---------------------===//
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//
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// This file implements the code shared between the LLVM inliners. This
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// implements all of the boring mechanics of the bottom-up inlining.
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//
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//===----------------------------------------------------------------------===//
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#include "Inliner.h"
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#include "llvm/Module.h"
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#include "llvm/iOther.h"
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#include "llvm/iTerminators.h"
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#include "llvm/Analysis/CallGraph.h"
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#include "llvm/Support/CallSite.h"
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#include "llvm/Transforms/Utils/Cloning.h"
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#include "Support/CommandLine.h"
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#include "Support/Debug.h"
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#include "Support/Statistic.h"
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namespace {
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Statistic<> NumInlined("inline", "Number of functions inlined");
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Statistic<> NumDeleted("inline", "Number of functions deleted because all callers found");
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cl::opt<unsigned> // FIXME: 200 is VERY conservative
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InlineLimit("inline-threshold", cl::Hidden, cl::init(200),
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cl::desc("Control the amount of inlining to perform (default = 200)"));
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}
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Inliner::Inliner() : InlineThreshold(InlineLimit) {}
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int Inliner::getRecursiveInlineCost(CallSite CS) {
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return getInlineCost(CS);
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}
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bool Inliner::runOnSCC(const std::vector<CallGraphNode*> &SCC) {
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CallGraph &CG = getAnalysis<CallGraph>();
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std::set<Function*> SCCFunctions;
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DEBUG(std::cerr << "Inliner visiting SCC:");
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for (unsigned i = 0, e = SCC.size(); i != e; ++i) {
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SCCFunctions.insert(SCC[i]->getFunction());
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DEBUG(std::cerr << " " << (SCC[i]->getFunction() ?
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SCC[i]->getFunction()->getName() : "INDIRECTNODE"));
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}
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DEBUG(std::cerr << "\n");
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bool Changed = false;
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for (std::set<Function*>::iterator SCCI = SCCFunctions.begin(),
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E = SCCFunctions.end(); SCCI != E; ++SCCI) {
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Function *F = *SCCI;
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if (F == 0 || F->isExternal()) continue;
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DEBUG(std::cerr << " Inspecting function: " << F->getName() << "\n");
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for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
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for (BasicBlock::iterator I = BB->begin(); I != BB->end(); ) {
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bool ShouldInc = true;
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// Found a call or invoke instruction?
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if (isa<CallInst>(I) || isa<InvokeInst>(I)) {
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CallSite CS = CallSite::get(I);
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if (Function *Callee = CS.getCalledFunction())
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if (!Callee->isExternal()) {
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// Determine whether this is a function IN the SCC...
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bool inSCC = SCCFunctions.count(Callee);
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// If the policy determines that we should inline this function,
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// try to do so...
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int InlineCost = inSCC ? getRecursiveInlineCost(CS) :
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getInlineCost(CS);
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if (InlineCost < (int)InlineThreshold) {
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DEBUG(std::cerr << " Inlining: cost=" << InlineCost
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<< ", Call: " << *CS.getInstruction());
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// Save an iterator to the instruction before the call if it
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// exists, otherwise get an iterator at the end of the
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// block... because the call will be destroyed.
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//
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BasicBlock::iterator SI;
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if (I != BB->begin()) {
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SI = I; --SI; // Instruction before the call...
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} else {
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SI = BB->end();
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}
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if (performInlining(CS, SCCFunctions)) {
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// Move to instruction before the call...
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I = (SI == BB->end()) ? BB->begin() : SI;
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ShouldInc = false; // Don't increment iterator until next time
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Changed = true;
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}
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}
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}
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}
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if (ShouldInc) ++I;
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}
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}
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return Changed;
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}
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bool Inliner::performInlining(CallSite CS, std::set<Function*> &SCC) {
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Function *Callee = CS.getCalledFunction();
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Function *Caller = CS.getInstruction()->getParent()->getParent();
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// Attempt to inline the function...
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if (!InlineFunction(CS)) return false;
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++NumInlined;
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// If we inlined the last possible call site to the function,
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// delete the function body now.
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if (Callee->use_empty() && Callee != Caller &&
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(Callee->hasInternalLinkage() || Callee->hasLinkOnceLinkage())) {
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DEBUG(std::cerr << " -> Deleting dead function: "
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<< Callee->getName() << "\n");
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std::set<Function*>::iterator I = SCC.find(Callee);
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if (I != SCC.end()) // Remove function from this SCC...
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SCC.erase(I);
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Callee->getParent()->getFunctionList().erase(Callee);
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++NumDeleted;
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}
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return true;
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}
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52
lib/Transforms/IPO/Inliner.h
Normal file
52
lib/Transforms/IPO/Inliner.h
Normal file
@ -0,0 +1,52 @@
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//===- InlineCommon.h - Code common to all inliners -------------*- C++ -*-===//
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//
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// This file defines a simple policy-based bottom-up inliner. This file
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// implements all of the boring mechanics of the bottom-up inlining, while the
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// subclass determines WHAT to inline, which is the much more interesting
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// component.
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//
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//===----------------------------------------------------------------------===//
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#ifndef INLINER_H
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#define INLINER_H
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#define DEBUG_TYPE "inline"
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#include "llvm/CallGraphSCCPass.h"
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#include <set>
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class CallSite;
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/// Inliner - This class contains all of the helper code which is used to
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/// perform the inlining operations that does not depend on the policy.
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///
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struct Inliner : public CallGraphSCCPass {
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Inliner();
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// Main run interface method, this implements the interface required by the
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// Pass class.
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virtual bool runOnSCC(const std::vector<CallGraphNode *> &SCC);
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/// This method returns the value specified by the -inline-threshold value,
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/// specified on the command line. This is typically not directly needed.
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///
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unsigned getInlineThreshold() const { return InlineThreshold; }
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/// getInlineCost - This method must be implemented by the subclass to
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/// determine the cost of inlining the specified call site. If the cost
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/// returned is greater than the current inline threshold, the call site is
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/// not inlined.
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///
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virtual int getInlineCost(CallSite CS) = 0;
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/// getRecursiveInlineCost - This method can be implemented by subclasses if
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/// it wants to treat calls to functions within the current SCC specially. If
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/// this method is not overloaded, it just chains to getInlineCost().
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///
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virtual int getRecursiveInlineCost(CallSite CS);
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private:
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unsigned InlineThreshold;
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bool performInlining(CallSite CS, std::set<Function*> &SCC);
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};
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#endif
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