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//===-- BasicBlockSectionsProfileReader.h - BB sections profile reader pass ==//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This pass creates the basic block cluster info by reading the basic block
// sections profile. The cluster info will be used by the basic-block-sections
// pass to arrange basic blocks in their sections.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_BASICBLOCKSECTIONSPROFILEREADER_H
#define LLVM_CODEGEN_BASICBLOCKSECTIONSPROFILEREADER_H
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/PassManager.h"
#include "llvm/InitializePasses.h"
#include "llvm/Pass.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/LineIterator.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Target/TargetMachine.h"
using namespace llvm;
namespace llvm {
// This struct represents the cluster information for a machine basic block,
// which is specifed by a unique ID (`MachineBasicBlock::BBID`).
struct BBClusterInfo {
// Basic block ID.
UniqueBBID BBID;
// Cluster ID this basic block belongs to.
unsigned ClusterID;
// Position of basic block within the cluster.
unsigned PositionInCluster;
};
// This represents the raw input profile for one function.
struct FunctionPathAndClusterInfo {
// BB Cluster information specified by `UniqueBBID`s.
SmallVector<BBClusterInfo> ClusterInfo;
// Paths to clone. A path a -> b -> c -> d implies cloning b, c, and d along
// the edge a -> b (a is not cloned). The index of the path in this vector
// determines the `UniqueBBID::CloneID` of the cloned blocks in that path.
SmallVector<SmallVector<unsigned>> ClonePaths;
};
// Provides DenseMapInfo for UniqueBBID.
template <> struct DenseMapInfo<UniqueBBID> {
static inline UniqueBBID getEmptyKey() {
unsigned EmptyKey = DenseMapInfo<unsigned>::getEmptyKey();
return UniqueBBID{EmptyKey, EmptyKey};
}
static inline UniqueBBID getTombstoneKey() {
unsigned TombstoneKey = DenseMapInfo<unsigned>::getTombstoneKey();
return UniqueBBID{TombstoneKey, TombstoneKey};
}
static unsigned getHashValue(const UniqueBBID &Val) {
std::pair<unsigned, unsigned> PairVal =
std::make_pair(Val.BaseID, Val.CloneID);
return DenseMapInfo<std::pair<unsigned, unsigned>>::getHashValue(PairVal);
}
static bool isEqual(const UniqueBBID &LHS, const UniqueBBID &RHS) {
return DenseMapInfo<unsigned>::isEqual(LHS.BaseID, RHS.BaseID) &&
DenseMapInfo<unsigned>::isEqual(LHS.CloneID, RHS.CloneID);
}
};
class BasicBlockSectionsProfileReader {
public:
friend class BasicBlockSectionsProfileReaderWrapperPass;
BasicBlockSectionsProfileReader(const MemoryBuffer *Buf)
: MBuf(Buf), LineIt(*Buf, /*SkipBlanks=*/true, /*CommentMarker=*/'#'){};
BasicBlockSectionsProfileReader(){};
// Returns true if basic block sections profile exist for function \p
// FuncName.
bool isFunctionHot(StringRef FuncName) const;
// Returns a pair with first element representing whether basic block sections
// profile exist for the function \p FuncName, and the second element
// representing the basic block sections profile (cluster info) for this
// function. If the first element is true and the second element is empty, it
// means unique basic block sections are desired for all basic blocks of the
// function.
std::pair<bool, SmallVector<BBClusterInfo>>
getClusterInfoForFunction(StringRef FuncName) const;
// Returns the path clonings for the given function.
SmallVector<SmallVector<unsigned>>
getClonePathsForFunction(StringRef FuncName) const;
private:
StringRef getAliasName(StringRef FuncName) const {
auto R = FuncAliasMap.find(FuncName);
return R == FuncAliasMap.end() ? FuncName : R->second;
}
// Returns a profile parsing error for the current line.
Error createProfileParseError(Twine Message) const {
return make_error<StringError>(
Twine("invalid profile " + MBuf->getBufferIdentifier() + " at line " +
Twine(LineIt.line_number()) + ": " + Message),
inconvertibleErrorCode());
}
// Parses a `UniqueBBID` from `S`. `S` must be in the form "<bbid>"
// (representing an original block) or "<bbid>.<cloneid>" (representing a
// cloned block) where bbid is a non-negative integer and cloneid is a
// positive integer.
Expected<UniqueBBID> parseUniqueBBID(StringRef S) const;
// Reads the basic block sections profile for functions in this module.
Error ReadProfile();
// Reads version 0 profile.
// TODO: Remove this function once version 0 is deprecated.
Error ReadV0Profile();
// Reads version 1 profile.
Error ReadV1Profile();
// This contains the basic-block-sections profile.
const MemoryBuffer *MBuf = nullptr;
// Iterator to the line being parsed.
line_iterator LineIt;
// Map from every function name in the module to its debug info filename or
// empty string if no debug info is available.
StringMap<SmallString<128>> FunctionNameToDIFilename;
// This contains the BB cluster information for the whole program.
//
// For every function name, it contains the cloning and cluster information
// for (all or some of) its basic blocks. The cluster information for every
// basic block includes its cluster ID along with the position of the basic
// block in that cluster.
StringMap<FunctionPathAndClusterInfo> ProgramPathAndClusterInfo;
// Some functions have alias names. We use this map to find the main alias
// name which appears in ProgramPathAndClusterInfo as a key.
StringMap<StringRef> FuncAliasMap;
};
// Creates a BasicBlockSectionsProfileReader pass to parse the basic block
// sections profile. \p Buf is a memory buffer that contains the list of
// functions and basic block ids to selectively enable basic block sections.
ImmutablePass *
createBasicBlockSectionsProfileReaderWrapperPass(const MemoryBuffer *Buf);
/// Analysis pass providing the \c BasicBlockSectionsProfileReader.
///
/// Note that this pass's result cannot be invalidated, it is immutable for the
/// life of the module.
class BasicBlockSectionsProfileReaderAnalysis
: public AnalysisInfoMixin<BasicBlockSectionsProfileReaderAnalysis> {
public:
static AnalysisKey Key;
typedef BasicBlockSectionsProfileReader Result;
BasicBlockSectionsProfileReaderAnalysis(const TargetMachine *TM) : TM(TM) {}
Result run(Function &F, FunctionAnalysisManager &AM);
private:
const TargetMachine *TM;
};
class BasicBlockSectionsProfileReaderWrapperPass : public ImmutablePass {
public:
static char ID;
BasicBlockSectionsProfileReader BBSPR;
BasicBlockSectionsProfileReaderWrapperPass(const MemoryBuffer *Buf)
: ImmutablePass(ID), BBSPR(BasicBlockSectionsProfileReader(Buf)) {
initializeBasicBlockSectionsProfileReaderWrapperPassPass(
*PassRegistry::getPassRegistry());
};
BasicBlockSectionsProfileReaderWrapperPass()
: ImmutablePass(ID), BBSPR(BasicBlockSectionsProfileReader()) {
initializeBasicBlockSectionsProfileReaderWrapperPassPass(
*PassRegistry::getPassRegistry());
}
StringRef getPassName() const override {
return "Basic Block Sections Profile Reader";
}
bool isFunctionHot(StringRef FuncName) const;
std::pair<bool, SmallVector<BBClusterInfo>>
getClusterInfoForFunction(StringRef FuncName) const;
SmallVector<SmallVector<unsigned>>
getClonePathsForFunction(StringRef FuncName) const;
// Initializes the FunctionNameToDIFilename map for the current module and
// then reads the profile for the matching functions.
bool doInitialization(Module &M) override;
BasicBlockSectionsProfileReader &getBBSPR();
};
} // namespace llvm
#endif // LLVM_CODEGEN_BASICBLOCKSECTIONSPROFILEREADER_H
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