1 //===- Transforms/Instrumentation.h - Instrumentation passes ----*- C++ -*-===// 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 file defines constructor functions for instrumentation passes. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_TRANSFORMS_INSTRUMENTATION_H 14 #define LLVM_TRANSFORMS_INSTRUMENTATION_H 15 16 #include "llvm/ADT/StringRef.h" 17 #include "llvm/IR/BasicBlock.h" 18 #include <cassert> 19 #include <cstdint> 20 #include <limits> 21 #include <string> 22 #include <vector> 23 24 namespace llvm { 25 26 class Triple; 27 class FunctionPass; 28 class ModulePass; 29 class OptimizationRemarkEmitter; 30 class Comdat; 31 32 /// Instrumentation passes often insert conditional checks into entry blocks. 33 /// Call this function before splitting the entry block to move instructions 34 /// that must remain in the entry block up before the split point. Static 35 /// allocas and llvm.localescape calls, for example, must remain in the entry 36 /// block. 37 BasicBlock::iterator PrepareToSplitEntryBlock(BasicBlock &BB, 38 BasicBlock::iterator IP); 39 40 // Create a constant for Str so that we can pass it to the run-time lib. 41 GlobalVariable *createPrivateGlobalForString(Module &M, StringRef Str, 42 bool AllowMerging, 43 const char *NamePrefix = ""); 44 45 // Returns F.getComdat() if it exists. 46 // Otherwise creates a new comdat, sets F's comdat, and returns it. 47 // Returns nullptr on failure. 48 Comdat *GetOrCreateFunctionComdat(Function &F, Triple &T, 49 const std::string &ModuleId); 50 51 // Insert GCOV profiling instrumentation 52 struct GCOVOptions { 53 static GCOVOptions getDefault(); 54 55 // Specify whether to emit .gcno files. 56 bool EmitNotes; 57 58 // Specify whether to modify the program to emit .gcda files when run. 59 bool EmitData; 60 61 // A four-byte version string. The meaning of a version string is described in 62 // gcc's gcov-io.h 63 char Version[4]; 64 65 // Emit a "cfg checksum" that follows the "line number checksum" of a 66 // function. This affects both .gcno and .gcda files. 67 bool UseCfgChecksum; 68 69 // Add the 'noredzone' attribute to added runtime library calls. 70 bool NoRedZone; 71 72 // Emit the name of the function in the .gcda files. This is redundant, as 73 // the function identifier can be used to find the name from the .gcno file. 74 bool FunctionNamesInData; 75 76 // Emit the exit block immediately after the start block, rather than after 77 // all of the function body's blocks. 78 bool ExitBlockBeforeBody; 79 80 // Regexes separated by a semi-colon to filter the files to instrument. 81 std::string Filter; 82 83 // Regexes separated by a semi-colon to filter the files to not instrument. 84 std::string Exclude; 85 }; 86 87 ModulePass *createGCOVProfilerPass(const GCOVOptions &Options = 88 GCOVOptions::getDefault()); 89 90 // PGO Instrumention. Parameter IsCS indicates if this is the context senstive 91 // instrumentation. 92 ModulePass *createPGOInstrumentationGenLegacyPass(bool IsCS = false); 93 ModulePass * 94 createPGOInstrumentationUseLegacyPass(StringRef Filename = StringRef(""), 95 bool IsCS = false); 96 ModulePass *createPGOInstrumentationGenCreateVarLegacyPass( 97 StringRef CSInstrName = StringRef("")); 98 ModulePass *createPGOIndirectCallPromotionLegacyPass(bool InLTO = false, 99 bool SamplePGO = false); 100 FunctionPass *createPGOMemOPSizeOptLegacyPass(); 101 102 // The pgo-specific indirect call promotion function declared below is used by 103 // the pgo-driven indirect call promotion and sample profile passes. It's a 104 // wrapper around llvm::promoteCall, et al. that additionally computes !prof 105 // metadata. We place it in a pgo namespace so it's not confused with the 106 // generic utilities. 107 namespace pgo { 108 109 // Helper function that transforms Inst (either an indirect-call instruction, or 110 // an invoke instruction , to a conditional call to F. This is like: 111 // if (Inst.CalledValue == F) 112 // F(...); 113 // else 114 // Inst(...); 115 // end 116 // TotalCount is the profile count value that the instruction executes. 117 // Count is the profile count value that F is the target function. 118 // These two values are used to update the branch weight. 119 // If \p AttachProfToDirectCall is true, a prof metadata is attached to the 120 // new direct call to contain \p Count. 121 // Returns the promoted direct call instruction. 122 Instruction *promoteIndirectCall(Instruction *Inst, Function *F, uint64_t Count, 123 uint64_t TotalCount, 124 bool AttachProfToDirectCall, 125 OptimizationRemarkEmitter *ORE); 126 } // namespace pgo 127 128 /// Options for the frontend instrumentation based profiling pass. 129 struct InstrProfOptions { 130 // Add the 'noredzone' attribute to added runtime library calls. 131 bool NoRedZone = false; 132 133 // Do counter register promotion 134 bool DoCounterPromotion = false; 135 136 // Use atomic profile counter increments. 137 bool Atomic = false; 138 139 // Use BFI to guide register promotion 140 bool UseBFIInPromotion = false; 141 142 // Name of the profile file to use as output 143 std::string InstrProfileOutput; 144 145 InstrProfOptions() = default; 146 }; 147 148 /// Insert frontend instrumentation based profiling. Parameter IsCS indicates if 149 // this is the context senstive instrumentation. 150 ModulePass *createInstrProfilingLegacyPass( 151 const InstrProfOptions &Options = InstrProfOptions(), bool IsCS = false); 152 153 ModulePass *createInstrOrderFilePass(); 154 155 // Insert DataFlowSanitizer (dynamic data flow analysis) instrumentation 156 ModulePass *createDataFlowSanitizerPass( 157 const std::vector<std::string> &ABIListFiles = std::vector<std::string>(), 158 void *(*getArgTLS)() = nullptr, void *(*getRetValTLS)() = nullptr); 159 160 // Options for sanitizer coverage instrumentation. 161 struct SanitizerCoverageOptions { 162 enum Type { 163 SCK_None = 0, 164 SCK_Function, 165 SCK_BB, 166 SCK_Edge 167 } CoverageType = SCK_None; 168 bool IndirectCalls = false; 169 bool TraceBB = false; 170 bool TraceCmp = false; 171 bool TraceDiv = false; 172 bool TraceGep = false; 173 bool Use8bitCounters = false; 174 bool TracePC = false; 175 bool TracePCGuard = false; 176 bool Inline8bitCounters = false; 177 bool PCTable = false; 178 bool NoPrune = false; 179 bool StackDepth = false; 180 181 SanitizerCoverageOptions() = default; 182 }; 183 184 /// Calculate what to divide by to scale counts. 185 /// 186 /// Given the maximum count, calculate a divisor that will scale all the 187 /// weights to strictly less than std::numeric_limits<uint32_t>::max(). 188 static inline uint64_t calculateCountScale(uint64_t MaxCount) { 189 return MaxCount < std::numeric_limits<uint32_t>::max() 190 ? 1 191 : MaxCount / std::numeric_limits<uint32_t>::max() + 1; 192 } 193 194 /// Scale an individual branch count. 195 /// 196 /// Scale a 64-bit weight down to 32-bits using \c Scale. 197 /// 198 static inline uint32_t scaleBranchCount(uint64_t Count, uint64_t Scale) { 199 uint64_t Scaled = Count / Scale; 200 assert(Scaled <= std::numeric_limits<uint32_t>::max() && "overflow 32-bits"); 201 return Scaled; 202 } 203 } // end namespace llvm 204 205 #endif // LLVM_TRANSFORMS_INSTRUMENTATION_H 206