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llvm-mirror/lib/IR/PassManager.cpp
Reid Kleckner 9369556310 Add PassManagerImpl.h to hide implementation details
ClangBuildAnalyzer results show that a lot of time is spent
instantiating AnalysisManager::getResultImpl across the code base:

**** Templates that took longest to instantiate:
 50445 ms: llvm::AnalysisManager<llvm::Function>::getResultImpl (412 times, avg 122 ms)
 47797 ms: llvm::AnalysisManager<llvm::Function>::getResult<llvm::TargetLibraryAnalysis> (389 times, avg 122 ms)
 46894 ms: std::tie<const unsigned long long, const bool> (2452 times, avg 19 ms)
 43851 ms: llvm::BumpPtrAllocatorImpl<llvm::MallocAllocator, 4096, 4096>::Allocate (3228 times, avg 13 ms)
 33911 ms: std::tie<const unsigned int, const unsigned int, const unsigned int, const unsigned int> (897 times, avg 37 ms)
 33854 ms: std::tie<const unsigned long long, const unsigned long long> (1897 times, avg 17 ms)
 27886 ms: std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string (11156 times, avg 2 ms)

I mentioned this result to @chandlerc, and he suggested this direction.

AnalysisManager is already explicitly instantiated, and getResultImpl
doesn't need to be inlined. Move the definition to an Impl header, and
include that header in files that explicitly instantiate
AnalysisManager. There are only four (real) IR units:
- function
- module
- loop
- cgscc

Looking at a specific transform (ArgumentPromotion.cpp), here are three
compilations before & after this change:

BEFORE:
$ for i in $(seq 3) ; do ./ccit.bat ; done
peak memory: 258.15MB
real: 0m6.297s
peak memory: 257.54MB
real: 0m5.906s
peak memory: 257.47MB
real: 0m6.219s

AFTER:
$ for i in $(seq 3) ; do ./ccit.bat ; done
peak memory: 235.35MB
real: 0m5.454s
peak memory: 234.72MB
real: 0m5.235s
peak memory: 234.39MB
real: 0m5.469s

The 20MB of memory saved seems real, and the time improvement seems like
it is there.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D73817
2020-02-03 11:15:55 -08:00

97 lines
3.7 KiB
C++

//===- PassManager.cpp - Infrastructure for managing & running IR passes --===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/IR/PassManager.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/PassManagerImpl.h"
using namespace llvm;
// Explicit template instantiations and specialization defininitions for core
// template typedefs.
namespace llvm {
template class AllAnalysesOn<Module>;
template class AllAnalysesOn<Function>;
template class PassManager<Module>;
template class PassManager<Function>;
template class AnalysisManager<Module>;
template class AnalysisManager<Function>;
template class InnerAnalysisManagerProxy<FunctionAnalysisManager, Module>;
template class OuterAnalysisManagerProxy<ModuleAnalysisManager, Function>;
template <>
bool FunctionAnalysisManagerModuleProxy::Result::invalidate(
Module &M, const PreservedAnalyses &PA,
ModuleAnalysisManager::Invalidator &Inv) {
// If literally everything is preserved, we're done.
if (PA.areAllPreserved())
return false; // This is still a valid proxy.
// If this proxy isn't marked as preserved, then even if the result remains
// valid, the key itself may no longer be valid, so we clear everything.
//
// Note that in order to preserve this proxy, a module pass must ensure that
// the FAM has been completely updated to handle the deletion of functions.
// Specifically, any FAM-cached results for those functions need to have been
// forcibly cleared. When preserved, this proxy will only invalidate results
// cached on functions *still in the module* at the end of the module pass.
auto PAC = PA.getChecker<FunctionAnalysisManagerModuleProxy>();
if (!PAC.preserved() && !PAC.preservedSet<AllAnalysesOn<Module>>()) {
InnerAM->clear();
return true;
}
// Directly check if the relevant set is preserved.
bool AreFunctionAnalysesPreserved =
PA.allAnalysesInSetPreserved<AllAnalysesOn<Function>>();
// Now walk all the functions to see if any inner analysis invalidation is
// necessary.
for (Function &F : M) {
Optional<PreservedAnalyses> FunctionPA;
// Check to see whether the preserved set needs to be pruned based on
// module-level analysis invalidation that triggers deferred invalidation
// registered with the outer analysis manager proxy for this function.
if (auto *OuterProxy =
InnerAM->getCachedResult<ModuleAnalysisManagerFunctionProxy>(F))
for (const auto &OuterInvalidationPair :
OuterProxy->getOuterInvalidations()) {
AnalysisKey *OuterAnalysisID = OuterInvalidationPair.first;
const auto &InnerAnalysisIDs = OuterInvalidationPair.second;
if (Inv.invalidate(OuterAnalysisID, M, PA)) {
if (!FunctionPA)
FunctionPA = PA;
for (AnalysisKey *InnerAnalysisID : InnerAnalysisIDs)
FunctionPA->abandon(InnerAnalysisID);
}
}
// Check if we needed a custom PA set, and if so we'll need to run the
// inner invalidation.
if (FunctionPA) {
InnerAM->invalidate(F, *FunctionPA);
continue;
}
// Otherwise we only need to do invalidation if the original PA set didn't
// preserve all function analyses.
if (!AreFunctionAnalysesPreserved)
InnerAM->invalidate(F, PA);
}
// Return false to indicate that this result is still a valid proxy.
return false;
}
}
AnalysisSetKey CFGAnalyses::SetKey;
AnalysisSetKey PreservedAnalyses::AllAnalysesKey;