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c2f791d8a7
Summary: This is necessary for D21771. In order to add the hotness attribute to optimization remarks we need BFI to be available in all passes that emit optimization remarks. However we don't want to pay for computing BFI unless the hotness attribute is requested. This is achieved by making BFI lazy at the very high-level through a new analysis pass -- BFI is not calculated unless requested. I am adding a test to check the laziness under D21771 where the first user of the analysis is added. Reviewers: hfinkel, dexonsmith, davidxl Subscribers: davidxl, dexonsmith, llvm-commits Differential Revision: http://reviews.llvm.org/D22141 llvm-svn: 275250
69 lines
2.5 KiB
C++
69 lines
2.5 KiB
C++
//===- LazyBlockFrequencyInfo.cpp - Lazy Block Frequency Analysis ---------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This is an alternative analysis pass to BlockFrequencyInfoWrapperPass. The
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// difference is that with this pass the block frequencies are not computed when
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// the analysis pass is executed but rather when the BFI results is explicitly
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// requested by the analysis client.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Analysis/LazyBlockFrequencyInfo.h"
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#include "llvm/Analysis/BranchProbabilityInfo.h"
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#include "llvm/Analysis/LoopInfo.h"
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using namespace llvm;
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#define DEBUG_TYPE "lazy-block-freq"
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INITIALIZE_PASS_BEGIN(LazyBlockFrequencyInfoPass, DEBUG_TYPE,
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"Lazy Block Frequency Analysis", true, true)
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INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfoWrapperPass)
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INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
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INITIALIZE_PASS_END(LazyBlockFrequencyInfoPass, DEBUG_TYPE,
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"Lazy Block Frequency Analysis", true, true)
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char LazyBlockFrequencyInfoPass::ID = 0;
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LazyBlockFrequencyInfoPass::LazyBlockFrequencyInfoPass() : FunctionPass(ID) {
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initializeLazyBlockFrequencyInfoPassPass(*PassRegistry::getPassRegistry());
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}
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void LazyBlockFrequencyInfoPass::print(raw_ostream &OS, const Module *) const {
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LBFI.getCalculated().print(OS);
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}
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void LazyBlockFrequencyInfoPass::getAnalysisUsage(AnalysisUsage &AU) const {
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AU.addRequired<BranchProbabilityInfoWrapperPass>();
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AU.addRequired<LoopInfoWrapperPass>();
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AU.setPreservesAll();
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}
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void LazyBlockFrequencyInfoPass::releaseMemory() { LBFI.releaseMemory(); }
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bool LazyBlockFrequencyInfoPass::runOnFunction(Function &F) {
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BranchProbabilityInfo &BPI =
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getAnalysis<BranchProbabilityInfoWrapperPass>().getBPI();
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LoopInfo &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
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LBFI.setAnalysis(&F, &BPI, &LI);
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return false;
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}
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void LazyBlockFrequencyInfoPass::getLazyBFIAnalysisUsage(AnalysisUsage &AU) {
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AU.addRequired<BranchProbabilityInfoWrapperPass>();
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AU.addRequired<LazyBlockFrequencyInfoPass>();
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AU.addRequired<LoopInfoWrapperPass>();
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}
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void llvm::initializeLazyBFIPassPass(PassRegistry &Registry) {
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INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfoWrapperPass);
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INITIALIZE_PASS_DEPENDENCY(LazyBlockFrequencyInfoPass);
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INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass);
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}
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