forked from OSchip/llvm-project
93 lines
3.4 KiB
C++
93 lines
3.4 KiB
C++
//===-- CSPreInliner.h - Profile guided preinliner ---------------- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_TOOLS_LLVM_PROFGEN_PGOINLINEADVISOR_H
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#define LLVM_TOOLS_LLVM_PROFGEN_PGOINLINEADVISOR_H
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#include "llvm/ADT/PriorityQueue.h"
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#include "llvm/ProfileData/ProfileCommon.h"
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#include "llvm/ProfileData/SampleProf.h"
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#include "llvm/Transforms/IPO/ProfiledCallGraph.h"
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#include "llvm/Transforms/IPO/SampleContextTracker.h"
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using namespace llvm;
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using namespace sampleprof;
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namespace llvm {
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namespace sampleprof {
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// Inline candidate seen from profile
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struct ProfiledInlineCandidate {
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ProfiledInlineCandidate(const FunctionSamples *Samples, uint64_t Count)
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: CalleeSamples(Samples), CallsiteCount(Count),
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SizeCost(Samples->getBodySamples().size()) {}
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// Context-sensitive function profile for inline candidate
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const FunctionSamples *CalleeSamples;
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// Call site count for an inline candidate
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// TODO: make sure entry count for context profile and call site
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// target count for corresponding call are consistent.
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uint64_t CallsiteCount;
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// Size proxy for function under particular call context.
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// TODO: use post-inline callee size from debug info.
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uint64_t SizeCost;
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};
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// Inline candidate comparer using call site weight
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struct ProfiledCandidateComparer {
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bool operator()(const ProfiledInlineCandidate &LHS,
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const ProfiledInlineCandidate &RHS) {
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if (LHS.CallsiteCount != RHS.CallsiteCount)
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return LHS.CallsiteCount < RHS.CallsiteCount;
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if (LHS.SizeCost != RHS.SizeCost)
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return LHS.SizeCost > RHS.SizeCost;
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// Tie breaker using GUID so we have stable/deterministic inlining order
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assert(LHS.CalleeSamples && RHS.CalleeSamples &&
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"Expect non-null FunctionSamples");
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return LHS.CalleeSamples->getGUID(LHS.CalleeSamples->getName()) <
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RHS.CalleeSamples->getGUID(RHS.CalleeSamples->getName());
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}
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};
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using ProfiledCandidateQueue =
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PriorityQueue<ProfiledInlineCandidate, std::vector<ProfiledInlineCandidate>,
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ProfiledCandidateComparer>;
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// Pre-compilation inliner based on context-sensitive profile.
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// The PreInliner estimates inline decision using hotness from profile
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// and cost estimation from machine code size. It helps merges context
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// profile globally and achieves better post-inine profile quality, which
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// otherwise won't be possible for ThinLTO. It also reduce context profile
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// size by only keep context that is estimated to be inlined.
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class CSPreInliner {
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public:
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CSPreInliner(StringMap<FunctionSamples> &Profiles, uint64_t HotThreshold,
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uint64_t ColdThreshold);
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void run();
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private:
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bool getInlineCandidates(ProfiledCandidateQueue &CQueue,
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const FunctionSamples *FCallerContextSamples);
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std::vector<StringRef> buildTopDownOrder();
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void processFunction(StringRef Name);
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bool shouldInline(ProfiledInlineCandidate &Candidate);
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SampleContextTracker ContextTracker;
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StringMap<FunctionSamples> &ProfileMap;
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// Count thresholds to answer isHotCount and isColdCount queries.
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// Mirrors the threshold in ProfileSummaryInfo.
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uint64_t HotCountThreshold;
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uint64_t ColdCountThreshold;
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};
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} // end namespace sampleprof
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} // end namespace llvm
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#endif
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