1 //===-- BasicBlockSectionsProfileReader.h - BB sections profile reader pass ==// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This pass creates the basic block cluster info by reading the basic block 10 // sections profile. The cluster info will be used by the basic-block-sections 11 // pass to arrange basic blocks in their sections. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_CODEGEN_BASICBLOCKSECTIONSPROFILEREADER_H 16 #define LLVM_CODEGEN_BASICBLOCKSECTIONSPROFILEREADER_H 17 18 #include "llvm/ADT/SmallString.h" 19 #include "llvm/ADT/SmallVector.h" 20 #include "llvm/ADT/StringMap.h" 21 #include "llvm/ADT/StringRef.h" 22 #include "llvm/CodeGen/MachineBasicBlock.h" 23 #include "llvm/IR/Module.h" 24 #include "llvm/IR/PassManager.h" 25 #include "llvm/InitializePasses.h" 26 #include "llvm/Pass.h" 27 #include "llvm/Support/Error.h" 28 #include "llvm/Support/LineIterator.h" 29 #include "llvm/Support/MemoryBuffer.h" 30 #include "llvm/Target/TargetMachine.h" 31 32 using namespace llvm; 33 34 namespace llvm { 35 36 // This struct represents the cluster information for a machine basic block, 37 // which is specifed by a unique ID (`MachineBasicBlock::BBID`). 38 struct BBClusterInfo { 39 // Basic block ID. 40 UniqueBBID BBID; 41 // Cluster ID this basic block belongs to. 42 unsigned ClusterID; 43 // Position of basic block within the cluster. 44 unsigned PositionInCluster; 45 }; 46 47 // This represents the raw input profile for one function. 48 struct FunctionPathAndClusterInfo { 49 // BB Cluster information specified by `UniqueBBID`s. 50 SmallVector<BBClusterInfo> ClusterInfo; 51 // Paths to clone. A path a -> b -> c -> d implies cloning b, c, and d along 52 // the edge a -> b (a is not cloned). The index of the path in this vector 53 // determines the `UniqueBBID::CloneID` of the cloned blocks in that path. 54 SmallVector<SmallVector<unsigned>> ClonePaths; 55 }; 56 57 // Provides DenseMapInfo for UniqueBBID. 58 template <> struct DenseMapInfo<UniqueBBID> { 59 static inline UniqueBBID getEmptyKey() { 60 unsigned EmptyKey = DenseMapInfo<unsigned>::getEmptyKey(); 61 return UniqueBBID{EmptyKey, EmptyKey}; 62 } 63 static inline UniqueBBID getTombstoneKey() { 64 unsigned TombstoneKey = DenseMapInfo<unsigned>::getTombstoneKey(); 65 return UniqueBBID{TombstoneKey, TombstoneKey}; 66 } 67 static unsigned getHashValue(const UniqueBBID &Val) { 68 std::pair<unsigned, unsigned> PairVal = 69 std::make_pair(Val.BaseID, Val.CloneID); 70 return DenseMapInfo<std::pair<unsigned, unsigned>>::getHashValue(PairVal); 71 } 72 static bool isEqual(const UniqueBBID &LHS, const UniqueBBID &RHS) { 73 return DenseMapInfo<unsigned>::isEqual(LHS.BaseID, RHS.BaseID) && 74 DenseMapInfo<unsigned>::isEqual(LHS.CloneID, RHS.CloneID); 75 } 76 }; 77 78 class BasicBlockSectionsProfileReader { 79 public: 80 friend class BasicBlockSectionsProfileReaderWrapperPass; 81 BasicBlockSectionsProfileReader(const MemoryBuffer *Buf) 82 : MBuf(Buf), LineIt(*Buf, /*SkipBlanks=*/true, /*CommentMarker=*/'#'){}; 83 84 BasicBlockSectionsProfileReader(){}; 85 86 // Returns true if basic block sections profile exist for function \p 87 // FuncName. 88 bool isFunctionHot(StringRef FuncName) const; 89 90 // Returns a pair with first element representing whether basic block sections 91 // profile exist for the function \p FuncName, and the second element 92 // representing the basic block sections profile (cluster info) for this 93 // function. If the first element is true and the second element is empty, it 94 // means unique basic block sections are desired for all basic blocks of the 95 // function. 96 std::pair<bool, SmallVector<BBClusterInfo>> 97 getClusterInfoForFunction(StringRef FuncName) const; 98 99 // Returns the path clonings for the given function. 100 SmallVector<SmallVector<unsigned>> 101 getClonePathsForFunction(StringRef FuncName) const; 102 103 private: 104 StringRef getAliasName(StringRef FuncName) const { 105 auto R = FuncAliasMap.find(FuncName); 106 return R == FuncAliasMap.end() ? FuncName : R->second; 107 } 108 109 // Returns a profile parsing error for the current line. 110 Error createProfileParseError(Twine Message) const { 111 return make_error<StringError>( 112 Twine("invalid profile " + MBuf->getBufferIdentifier() + " at line " + 113 Twine(LineIt.line_number()) + ": " + Message), 114 inconvertibleErrorCode()); 115 } 116 117 // Parses a `UniqueBBID` from `S`. `S` must be in the form "<bbid>" 118 // (representing an original block) or "<bbid>.<cloneid>" (representing a 119 // cloned block) where bbid is a non-negative integer and cloneid is a 120 // positive integer. 121 Expected<UniqueBBID> parseUniqueBBID(StringRef S) const; 122 123 // Reads the basic block sections profile for functions in this module. 124 Error ReadProfile(); 125 126 // Reads version 0 profile. 127 // TODO: Remove this function once version 0 is deprecated. 128 Error ReadV0Profile(); 129 130 // Reads version 1 profile. 131 Error ReadV1Profile(); 132 133 // This contains the basic-block-sections profile. 134 const MemoryBuffer *MBuf = nullptr; 135 136 // Iterator to the line being parsed. 137 line_iterator LineIt; 138 139 // Map from every function name in the module to its debug info filename or 140 // empty string if no debug info is available. 141 StringMap<SmallString<128>> FunctionNameToDIFilename; 142 143 // This contains the BB cluster information for the whole program. 144 // 145 // For every function name, it contains the cloning and cluster information 146 // for (all or some of) its basic blocks. The cluster information for every 147 // basic block includes its cluster ID along with the position of the basic 148 // block in that cluster. 149 StringMap<FunctionPathAndClusterInfo> ProgramPathAndClusterInfo; 150 151 // Some functions have alias names. We use this map to find the main alias 152 // name which appears in ProgramPathAndClusterInfo as a key. 153 StringMap<StringRef> FuncAliasMap; 154 }; 155 156 // Creates a BasicBlockSectionsProfileReader pass to parse the basic block 157 // sections profile. \p Buf is a memory buffer that contains the list of 158 // functions and basic block ids to selectively enable basic block sections. 159 ImmutablePass * 160 createBasicBlockSectionsProfileReaderWrapperPass(const MemoryBuffer *Buf); 161 162 /// Analysis pass providing the \c BasicBlockSectionsProfileReader. 163 /// 164 /// Note that this pass's result cannot be invalidated, it is immutable for the 165 /// life of the module. 166 class BasicBlockSectionsProfileReaderAnalysis 167 : public AnalysisInfoMixin<BasicBlockSectionsProfileReaderAnalysis> { 168 169 public: 170 static AnalysisKey Key; 171 typedef BasicBlockSectionsProfileReader Result; 172 BasicBlockSectionsProfileReaderAnalysis(const TargetMachine *TM) : TM(TM) {} 173 174 Result run(Function &F, FunctionAnalysisManager &AM); 175 176 private: 177 const TargetMachine *TM; 178 }; 179 180 class BasicBlockSectionsProfileReaderWrapperPass : public ImmutablePass { 181 public: 182 static char ID; 183 BasicBlockSectionsProfileReader BBSPR; 184 185 BasicBlockSectionsProfileReaderWrapperPass(const MemoryBuffer *Buf) 186 : ImmutablePass(ID), BBSPR(BasicBlockSectionsProfileReader(Buf)) { 187 initializeBasicBlockSectionsProfileReaderWrapperPassPass( 188 *PassRegistry::getPassRegistry()); 189 }; 190 191 BasicBlockSectionsProfileReaderWrapperPass() 192 : ImmutablePass(ID), BBSPR(BasicBlockSectionsProfileReader()) { 193 initializeBasicBlockSectionsProfileReaderWrapperPassPass( 194 *PassRegistry::getPassRegistry()); 195 } 196 197 StringRef getPassName() const override { 198 return "Basic Block Sections Profile Reader"; 199 } 200 201 bool isFunctionHot(StringRef FuncName) const; 202 203 std::pair<bool, SmallVector<BBClusterInfo>> 204 getClusterInfoForFunction(StringRef FuncName) const; 205 206 SmallVector<SmallVector<unsigned>> 207 getClonePathsForFunction(StringRef FuncName) const; 208 209 // Initializes the FunctionNameToDIFilename map for the current module and 210 // then reads the profile for the matching functions. 211 bool doInitialization(Module &M) override; 212 213 BasicBlockSectionsProfileReader &getBBSPR(); 214 }; 215 216 } // namespace llvm 217 #endif // LLVM_CODEGEN_BASICBLOCKSECTIONSPROFILEREADER_H 218