220e77a83a
If we're using an old instrprof profile and the user passes we can get Decls with children decl counts not matching the what the profile was written against. In a particular case I was debugging we have 24 decls in the AST and 22 decls in the profile. Avoid crashing in this case. Differential Revision: https://reviews.llvm.org/D149504
130 lines
4.7 KiB
C++
130 lines
4.7 KiB
C++
//===--- CodeGenPGO.h - PGO Instrumentation for LLVM CodeGen ----*- 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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//
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// Instrumentation-based profile-guided optimization
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CLANG_LIB_CODEGEN_CODEGENPGO_H
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#define LLVM_CLANG_LIB_CODEGEN_CODEGENPGO_H
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#include "CGBuilder.h"
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#include "CodeGenModule.h"
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#include "CodeGenTypes.h"
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#include "llvm/ProfileData/InstrProfReader.h"
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#include <array>
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#include <memory>
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#include <optional>
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namespace clang {
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namespace CodeGen {
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/// Per-function PGO state.
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class CodeGenPGO {
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private:
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CodeGenModule &CGM;
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std::string FuncName;
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llvm::GlobalVariable *FuncNameVar;
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std::array <unsigned, llvm::IPVK_Last + 1> NumValueSites;
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unsigned NumRegionCounters;
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uint64_t FunctionHash;
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std::unique_ptr<llvm::DenseMap<const Stmt *, unsigned>> RegionCounterMap;
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std::unique_ptr<llvm::DenseMap<const Stmt *, uint64_t>> StmtCountMap;
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std::unique_ptr<llvm::InstrProfRecord> ProfRecord;
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std::vector<uint64_t> RegionCounts;
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uint64_t CurrentRegionCount;
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public:
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CodeGenPGO(CodeGenModule &CGModule)
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: CGM(CGModule), FuncNameVar(nullptr), NumValueSites({{0}}),
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NumRegionCounters(0), FunctionHash(0), CurrentRegionCount(0) {}
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/// Whether or not we have PGO region data for the current function. This is
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/// false both when we have no data at all and when our data has been
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/// discarded.
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bool haveRegionCounts() const { return !RegionCounts.empty(); }
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/// Return the counter value of the current region.
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uint64_t getCurrentRegionCount() const { return CurrentRegionCount; }
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/// Set the counter value for the current region. This is used to keep track
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/// of changes to the most recent counter from control flow and non-local
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/// exits.
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void setCurrentRegionCount(uint64_t Count) { CurrentRegionCount = Count; }
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/// Check if an execution count is known for a given statement. If so, return
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/// true and put the value in Count; else return false.
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std::optional<uint64_t> getStmtCount(const Stmt *S) const {
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if (!StmtCountMap)
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return std::nullopt;
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auto I = StmtCountMap->find(S);
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if (I == StmtCountMap->end())
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return std::nullopt;
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return I->second;
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}
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/// If the execution count for the current statement is known, record that
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/// as the current count.
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void setCurrentStmt(const Stmt *S) {
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if (auto Count = getStmtCount(S))
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setCurrentRegionCount(*Count);
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}
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/// Assign counters to regions and configure them for PGO of a given
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/// function. Does nothing if instrumentation is not enabled and either
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/// generates global variables or associates PGO data with each of the
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/// counters depending on whether we are generating or using instrumentation.
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void assignRegionCounters(GlobalDecl GD, llvm::Function *Fn);
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/// Emit a coverage mapping range with a counter zero
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/// for an unused declaration.
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void emitEmptyCounterMapping(const Decl *D, StringRef FuncName,
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llvm::GlobalValue::LinkageTypes Linkage);
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// Insert instrumentation or attach profile metadata at value sites
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void valueProfile(CGBuilderTy &Builder, uint32_t ValueKind,
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llvm::Instruction *ValueSite, llvm::Value *ValuePtr);
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// Set a module flag indicating if value profiling is enabled.
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void setValueProfilingFlag(llvm::Module &M);
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private:
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void setFuncName(llvm::Function *Fn);
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void setFuncName(StringRef Name, llvm::GlobalValue::LinkageTypes Linkage);
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void mapRegionCounters(const Decl *D);
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void computeRegionCounts(const Decl *D);
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void applyFunctionAttributes(llvm::IndexedInstrProfReader *PGOReader,
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llvm::Function *Fn);
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void loadRegionCounts(llvm::IndexedInstrProfReader *PGOReader,
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bool IsInMainFile);
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bool skipRegionMappingForDecl(const Decl *D);
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void emitCounterRegionMapping(const Decl *D);
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public:
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void emitCounterIncrement(CGBuilderTy &Builder, const Stmt *S,
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llvm::Value *StepV);
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/// Return the region count for the counter at the given index.
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uint64_t getRegionCount(const Stmt *S) {
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if (!RegionCounterMap)
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return 0;
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if (!haveRegionCounts())
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return 0;
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// With profiles from a differing version of clang we can have mismatched
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// decl counts. Don't crash in such a case.
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auto Index = (*RegionCounterMap)[S];
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if (Index >= RegionCounts.size())
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return 0;
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return RegionCounts[Index];
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}
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};
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} // end namespace CodeGen
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} // end namespace clang
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#endif
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