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65512647cc
The fact that PGO has a say in how these branch weights are determined isn't interesting to most of CodeGen, so it makes more sense for this API to be accessible via CodeGenFunction rather than CodeGenPGO. llvm-svn: 236380
122 lines
4.3 KiB
C++
122 lines
4.3 KiB
C++
//===--- CodeGenPGO.h - PGO Instrumentation for LLVM CodeGen ----*- C++ -*-===//
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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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// 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 "clang/Frontend/CodeGenOptions.h"
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#include "llvm/ADT/StringMap.h"
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#include "llvm/Support/MemoryBuffer.h"
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#include <memory>
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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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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::vector<uint64_t> RegionCounts;
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uint64_t CurrentRegionCount;
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/// \brief A flag that is set to true when this function doesn't need
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/// to have coverage mapping data.
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bool SkipCoverageMapping;
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public:
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CodeGenPGO(CodeGenModule &CGM)
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: CGM(CGM), NumRegionCounters(0), FunctionHash(0), CurrentRegionCount(0),
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SkipCoverageMapping(false) {}
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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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Optional<uint64_t> getStmtCount(const Stmt *S) {
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if (!StmtCountMap)
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return None;
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auto I = StmtCountMap->find(S);
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if (I == StmtCountMap->end())
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return None;
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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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/// Check if we need to emit coverage mapping for a given declaration
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void checkGlobalDecl(GlobalDecl GD);
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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(const Decl *D, 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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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 createFuncNameVar(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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void emitCounterVariables();
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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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/// 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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return RegionCounts[(*RegionCounterMap)[S]];
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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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