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//===- BlockFrequencyInfo.h - Block Frequency Analysis ----------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// Loops should be simplified before this analysis.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_BLOCKFREQUENCYINFO_H
#define LLVM_ANALYSIS_BLOCKFREQUENCYINFO_H
#include "llvm/IR/PassManager.h"
#include "llvm/Pass.h"
#include "llvm/Support/BlockFrequency.h"
#include "llvm/Support/Printable.h"
#include <cstdint>
#include <memory>
#include <optional>
namespace llvm {
class BasicBlock;
class BranchProbabilityInfo;
class Function;
class LoopInfo;
class Module;
class raw_ostream;
template <class BlockT> class BlockFrequencyInfoImpl;
enum PGOViewCountsType { PGOVCT_None, PGOVCT_Graph, PGOVCT_Text };
/// BlockFrequencyInfo pass uses BlockFrequencyInfoImpl implementation to
/// estimate IR basic block frequencies.
class BlockFrequencyInfo {
using ImplType = BlockFrequencyInfoImpl<BasicBlock>;
std::unique_ptr<ImplType> BFI;
public:
BlockFrequencyInfo();
BlockFrequencyInfo(const Function &F, const BranchProbabilityInfo &BPI,
const LoopInfo &LI);
BlockFrequencyInfo(const BlockFrequencyInfo &) = delete;
BlockFrequencyInfo &operator=(const BlockFrequencyInfo &) = delete;
BlockFrequencyInfo(BlockFrequencyInfo &&Arg);
BlockFrequencyInfo &operator=(BlockFrequencyInfo &&RHS);
~BlockFrequencyInfo();
/// Handle invalidation explicitly.
bool invalidate(Function &F, const PreservedAnalyses &PA,
FunctionAnalysisManager::Invalidator &);
const Function *getFunction() const;
const BranchProbabilityInfo *getBPI() const;
void view(StringRef = "BlockFrequencyDAGs") const;
/// getblockFreq - Return block frequency. Return 0 if we don't have the
/// information. Please note that initial frequency is equal to ENTRY_FREQ. It
/// means that we should not rely on the value itself, but only on the
/// comparison to the other block frequencies. We do this to avoid using of
/// floating points.
BlockFrequency getBlockFreq(const BasicBlock *BB) const;
/// Returns the estimated profile count of \p BB.
/// This computes the relative block frequency of \p BB and multiplies it by
/// the enclosing function's count (if available) and returns the value.
std::optional<uint64_t>
getBlockProfileCount(const BasicBlock *BB, bool AllowSynthetic = false) const;
/// Returns the estimated profile count of \p Freq.
/// This uses the frequency \p Freq and multiplies it by
/// the enclosing function's count (if available) and returns the value.
std::optional<uint64_t> getProfileCountFromFreq(BlockFrequency Freq) const;
/// Returns true if \p BB is an irreducible loop header
/// block. Otherwise false.
bool isIrrLoopHeader(const BasicBlock *BB);
// Set the frequency of the given basic block.
void setBlockFreq(const BasicBlock *BB, BlockFrequency Freq);
/// Set the frequency of \p ReferenceBB to \p Freq and scale the frequencies
/// of the blocks in \p BlocksToScale such that their frequencies relative
/// to \p ReferenceBB remain unchanged.
void setBlockFreqAndScale(const BasicBlock *ReferenceBB, BlockFrequency Freq,
SmallPtrSetImpl<BasicBlock *> &BlocksToScale);
/// calculate - compute block frequency info for the given function.
void calculate(const Function &F, const BranchProbabilityInfo &BPI,
const LoopInfo &LI);
BlockFrequency getEntryFreq() const;
void releaseMemory();
void print(raw_ostream &OS) const;
// Compare to the other BFI and verify they match.
void verifyMatch(BlockFrequencyInfo &Other) const;
};
/// Print the block frequency @p Freq relative to the current functions entry
/// frequency. Returns a Printable object that can be piped via `<<` to a
/// `raw_ostream`.
Printable printBlockFreq(const BlockFrequencyInfo &BFI, BlockFrequency Freq);
/// Convenience function equivalent to calling
/// `printBlockFreq(BFI, BFI.getBlocakFreq(&BB))`.
Printable printBlockFreq(const BlockFrequencyInfo &BFI, const BasicBlock &BB);
/// Analysis pass which computes \c BlockFrequencyInfo.
class BlockFrequencyAnalysis
: public AnalysisInfoMixin<BlockFrequencyAnalysis> {
friend AnalysisInfoMixin<BlockFrequencyAnalysis>;
static AnalysisKey Key;
public:
/// Provide the result type for this analysis pass.
using Result = BlockFrequencyInfo;
/// Run the analysis pass over a function and produce BFI.
Result run(Function &F, FunctionAnalysisManager &AM);
};
/// Printer pass for the \c BlockFrequencyInfo results.
class BlockFrequencyPrinterPass
: public PassInfoMixin<BlockFrequencyPrinterPass> {
raw_ostream &OS;
public:
explicit BlockFrequencyPrinterPass(raw_ostream &OS) : OS(OS) {}
PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
static bool isRequired() { return true; }
};
/// Legacy analysis pass which computes \c BlockFrequencyInfo.
class BlockFrequencyInfoWrapperPass : public FunctionPass {
BlockFrequencyInfo BFI;
public:
static char ID;
BlockFrequencyInfoWrapperPass();
~BlockFrequencyInfoWrapperPass() override;
BlockFrequencyInfo &getBFI() { return BFI; }
const BlockFrequencyInfo &getBFI() const { return BFI; }
void getAnalysisUsage(AnalysisUsage &AU) const override;
bool runOnFunction(Function &F) override;
void releaseMemory() override;
void print(raw_ostream &OS, const Module *M) const override;
};
} // end namespace llvm
#endif // LLVM_ANALYSIS_BLOCKFREQUENCYINFO_H
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