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