llvm-6502/lib/IR/PassManager.cpp
Chandler Carruth f348c9782c Introduce an AnalysisManager which is like a pass manager but with a lot
more smarts in it. This is where most of the interesting logic that used
to live in the implicit-scheduling-hackery of the old pass manager will
live.

Like the previous commits, note that this is a very early prototype!
I expect substantial changes before this is ready to use.

The core of the design is the following:

- We have an AnalysisManager which can be used across a series of
  passes over a module.
- The code setting up a pass pipeline registers the analyses available
  with the manager.
- Individual transform passes can check than an analysis manager
  provides the analyses they require in order to fail-fast.
- There is *no* implicit registration or scheduling.
- Analysis passes are different from other passes: they produce an
  analysis result that is cached and made available via the analysis
  manager.
- Cached results are invalidated automatically by the pass managers.
- When a transform pass requests an analysis result, either the analysis
  is run to produce the result or a cached result is provided.

There are a few aspects of this design that I *know* will change in
subsequent commits:
- Currently there is no "preservation" system, that needs to be added.
- All of the analysis management should move up to the analysis library.
- The analysis management needs to support at least SCC passes. Maybe
  loop passes. Living in the analysis library will facilitate this.
- Need support for analyses which are *both* module and function passes.
- Need support for pro-actively running module analyses to have cached
  results within a function pass manager.
- Need a clear design for "immutable" passes.
- Need support for requesting cached results when available and not
  re-running the pass even if that would be necessary.
- Need more thorough testing of all of this infrastructure.

There are other aspects that I view as open questions I'm hoping to
resolve as I iterate a bit on the infrastructure, and especially as
I start writing actual passes against this.
- Should we have separate management layers for function, module, and
  SCC analyses? I think "yes", but I'm not yet ready to switch the code.
  Adding SCC support will likely resolve this definitively.
- How should the 'require' functionality work? Should *that* be the only
  way to request results to ensure that passes always require things?
- How should preservation work?
- Probably some other things I'm forgetting. =]

Look forward to more patches in shorter order now that this is in place.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194538 91177308-0d34-0410-b5e6-96231b3b80d8
2013-11-13 01:12:08 +00:00

156 lines
6.0 KiB
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//===- PassManager.h - Infrastructure for managing & running IR passes ----===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/IR/PassManager.h"
#include "llvm/ADT/STLExtras.h"
using namespace llvm;
void ModulePassManager::run() {
for (unsigned Idx = 0, Size = Passes.size(); Idx != Size; ++Idx)
if (Passes[Idx]->run(M))
if (AM) AM->invalidateAll(M);
}
bool FunctionPassManager::run(Module *M) {
bool Changed = false;
for (Module::iterator I = M->begin(), E = M->end(); I != E; ++I)
for (unsigned Idx = 0, Size = Passes.size(); Idx != Size; ++Idx)
if (Passes[Idx]->run(I)) {
Changed = true;
if (AM) AM->invalidateAll(I);
}
return Changed;
}
void AnalysisManager::invalidateAll(Function *F) {
assert(F->getParent() == M && "Invalidating a function from another module!");
// First invalidate any module results we still have laying about.
// FIXME: This is a total hack based on the fact that erasure doesn't
// invalidate iteration for DenseMap.
for (ModuleAnalysisResultMapT::iterator I = ModuleAnalysisResults.begin(),
E = ModuleAnalysisResults.end();
I != E; ++I)
if (I->second->invalidate(M))
ModuleAnalysisResults.erase(I);
// Now clear all the invalidated results associated specifically with this
// function.
SmallVector<void *, 8> InvalidatedPassIDs;
FunctionAnalysisResultListT &ResultsList = FunctionAnalysisResultLists[F];
for (FunctionAnalysisResultListT::iterator I = ResultsList.begin(),
E = ResultsList.end();
I != E; ++I)
if (I->second->invalidate(F)) {
FunctionAnalysisResultListT::iterator Old = I--;
InvalidatedPassIDs.push_back(Old->first);
ResultsList.erase(Old);
}
while (!InvalidatedPassIDs.empty())
FunctionAnalysisResults.erase(
std::make_pair(InvalidatedPassIDs.pop_back_val(), F));
}
void AnalysisManager::invalidateAll(Module *M) {
// First invalidate any module results we still have laying about.
// FIXME: This is a total hack based on the fact that erasure doesn't
// invalidate iteration for DenseMap.
for (ModuleAnalysisResultMapT::iterator I = ModuleAnalysisResults.begin(),
E = ModuleAnalysisResults.end();
I != E; ++I)
if (I->second->invalidate(M))
ModuleAnalysisResults.erase(I);
// Now walk all of the functions for which there are cached results, and
// attempt to invalidate each of those as the entire module may have changed.
// FIXME: How do we handle functions which have been deleted or RAUWed?
SmallVector<void *, 8> InvalidatedPassIDs;
for (FunctionAnalysisResultListMapT::iterator
FI = FunctionAnalysisResultLists.begin(),
FE = FunctionAnalysisResultLists.end();
FI != FE; ++FI) {
Function *F = FI->first;
FunctionAnalysisResultListT &ResultsList = FI->second;
for (FunctionAnalysisResultListT::iterator I = ResultsList.begin(),
E = ResultsList.end();
I != E; ++I)
if (I->second->invalidate(F)) {
FunctionAnalysisResultListT::iterator Old = I--;
InvalidatedPassIDs.push_back(Old->first);
ResultsList.erase(Old);
}
while (!InvalidatedPassIDs.empty())
FunctionAnalysisResults.erase(
std::make_pair(InvalidatedPassIDs.pop_back_val(), F));
}
}
const AnalysisManager::AnalysisResultConcept<Module> &
AnalysisManager::getResultImpl(void *PassID, Module *M) {
assert(M == this->M && "Wrong module used when querying the AnalysisManager");
ModuleAnalysisResultMapT::iterator RI;
bool Inserted;
llvm::tie(RI, Inserted) = ModuleAnalysisResults.insert(std::make_pair(
PassID, polymorphic_ptr<AnalysisResultConcept<Module> >()));
if (Inserted) {
// We don't have a cached result for this result. Look up the pass and run
// it to produce a result, which we then add to the cache.
ModuleAnalysisPassMapT::const_iterator PI =
ModuleAnalysisPasses.find(PassID);
assert(PI != ModuleAnalysisPasses.end() &&
"Analysis passes must be registered prior to being queried!");
RI->second = PI->second->run(M);
}
return *RI->second;
}
const AnalysisManager::AnalysisResultConcept<Function> &
AnalysisManager::getResultImpl(void *PassID, Function *F) {
assert(F->getParent() == M && "Analyzing a function from another module!");
FunctionAnalysisResultMapT::iterator RI;
bool Inserted;
llvm::tie(RI, Inserted) = FunctionAnalysisResults.insert(std::make_pair(
std::make_pair(PassID, F), FunctionAnalysisResultListT::iterator()));
if (Inserted) {
// We don't have a cached result for this result. Look up the pass and run
// it to produce a result, which we then add to the cache.
FunctionAnalysisPassMapT::const_iterator PI =
FunctionAnalysisPasses.find(PassID);
assert(PI != FunctionAnalysisPasses.end() &&
"Analysis passes must be registered prior to being queried!");
FunctionAnalysisResultListT &ResultList = FunctionAnalysisResultLists[F];
ResultList.push_back(std::make_pair(PassID, PI->second->run(F)));
RI->second = llvm::prior(ResultList.end());
}
return *RI->second->second;
}
void AnalysisManager::invalidateImpl(void *PassID, Module *M) {
assert(M == this->M && "Invalidating a pass over a different module!");
ModuleAnalysisResults.erase(PassID);
}
void AnalysisManager::invalidateImpl(void *PassID, Function *F) {
assert(F->getParent() == M &&
"Invalidating a pass over a function from another module!");
FunctionAnalysisResultMapT::iterator RI = FunctionAnalysisResults.find(std::make_pair(PassID, F));
if (RI == FunctionAnalysisResults.end())
return;
FunctionAnalysisResultLists[F].erase(RI->second);
}