llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp

   1 //===-- SanitizerCoverage.cpp - coverage instrumentation for sanitizers ---===//
   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 // Coverage instrumentation done on LLVM IR level, works with Sanitizers.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "llvm/Transforms/Instrumentation/SanitizerCoverage.h"
  14 #include "llvm/ADT/ArrayRef.h"
  15 #include "llvm/ADT/SmallVector.h"
  16 #include "llvm/Analysis/EHPersonalities.h"
  17 #include "llvm/Analysis/PostDominators.h"
  18 #include "llvm/IR/CFG.h"
  19 #include "llvm/IR/Constant.h"
  20 #include "llvm/IR/DataLayout.h"
  21 #include "llvm/IR/DebugInfo.h"
  22 #include "llvm/IR/Dominators.h"
  23 #include "llvm/IR/Function.h"
  24 #include "llvm/IR/GlobalVariable.h"
  25 #include "llvm/IR/IRBuilder.h"
  26 #include "llvm/IR/InlineAsm.h"
  27 #include "llvm/IR/IntrinsicInst.h"
  28 #include "llvm/IR/Intrinsics.h"
  29 #include "llvm/IR/LLVMContext.h"
  30 #include "llvm/IR/MDBuilder.h"
  31 #include "llvm/IR/Mangler.h"
  32 #include "llvm/IR/Module.h"
  33 #include "llvm/IR/Type.h"
  34 #include "llvm/InitializePasses.h"
  35 #include "llvm/Support/CommandLine.h"
  36 #include "llvm/Support/Debug.h"
  37 #include "llvm/Support/SpecialCaseList.h"
  38 #include "llvm/Support/VirtualFileSystem.h"
  39 #include "llvm/Support/raw_ostream.h"
  40 #include "llvm/Transforms/Instrumentation.h"
  41 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
  42 #include "llvm/Transforms/Utils/ModuleUtils.h"
  43
  44 using namespace llvm;
  45
  46 #define DEBUG_TYPE "sancov"
  47
  48 const char SanCovTracePCIndirName[] = "__sanitizer_cov_trace_pc_indir";
  49 const char SanCovTracePCName[] = "__sanitizer_cov_trace_pc";
  50 const char SanCovTraceCmp1[] = "__sanitizer_cov_trace_cmp1";
  51 const char SanCovTraceCmp2[] = "__sanitizer_cov_trace_cmp2";
  52 const char SanCovTraceCmp4[] = "__sanitizer_cov_trace_cmp4";
  53 const char SanCovTraceCmp8[] = "__sanitizer_cov_trace_cmp8";
  54 const char SanCovTraceConstCmp1[] = "__sanitizer_cov_trace_const_cmp1";
  55 const char SanCovTraceConstCmp2[] = "__sanitizer_cov_trace_const_cmp2";
  56 const char SanCovTraceConstCmp4[] = "__sanitizer_cov_trace_const_cmp4";
  57 const char SanCovTraceConstCmp8[] = "__sanitizer_cov_trace_const_cmp8";
  58 const char SanCovTraceDiv4[] = "__sanitizer_cov_trace_div4";
  59 const char SanCovTraceDiv8[] = "__sanitizer_cov_trace_div8";
  60 const char SanCovTraceGep[] = "__sanitizer_cov_trace_gep";
  61 const char SanCovTraceSwitchName[] = "__sanitizer_cov_trace_switch";
  62 const char SanCovModuleCtorTracePcGuardName[] =
  63     "sancov.module_ctor_trace_pc_guard";
  64 const char SanCovModuleCtor8bitCountersName[] =
  65     "sancov.module_ctor_8bit_counters";
  66 const char SanCovModuleCtorBoolFlagName[] = "sancov.module_ctor_bool_flag";
  67 static const uint64_t SanCtorAndDtorPriority = 2;
  68
  69 const char SanCovTracePCGuardName[] = "__sanitizer_cov_trace_pc_guard";
  70 const char SanCovTracePCGuardInitName[] = "__sanitizer_cov_trace_pc_guard_init";
  71 const char SanCov8bitCountersInitName[] = "__sanitizer_cov_8bit_counters_init";
  72 const char SanCovBoolFlagInitName[] = "__sanitizer_cov_bool_flag_init";
  73 const char SanCovPCsInitName[] = "__sanitizer_cov_pcs_init";
  74
  75 const char SanCovGuardsSectionName[] = "sancov_guards";
  76 const char SanCovCountersSectionName[] = "sancov_cntrs";
  77 const char SanCovBoolFlagSectionName[] = "sancov_bools";
  78 const char SanCovPCsSectionName[] = "sancov_pcs";
  79
  80 const char SanCovLowestStackName[] = "__sancov_lowest_stack";
  81
  82 static cl::opt<int> ClCoverageLevel(
  83     "sanitizer-coverage-level",
  84     cl::desc("Sanitizer Coverage. 0: none, 1: entry block, 2: all blocks, "
  85              "3: all blocks and critical edges"),
  86     cl::Hidden, cl::init(0));
  87
  88 static cl::opt<bool> ClTracePC("sanitizer-coverage-trace-pc",
  89                                cl::desc("Experimental pc tracing"), cl::Hidden,
  90                                cl::init(false));
  91
  92 static cl::opt<bool> ClTracePCGuard("sanitizer-coverage-trace-pc-guard",
  93                                     cl::desc("pc tracing with a guard"),
  94                                     cl::Hidden, cl::init(false));
  95
  96 // If true, we create a global variable that contains PCs of all instrumented
  97 // BBs, put this global into a named section, and pass this section's bounds
  98 // to __sanitizer_cov_pcs_init.
  99 // This way the coverage instrumentation does not need to acquire the PCs
 100 // at run-time. Works with trace-pc-guard, inline-8bit-counters, and
 101 // inline-bool-flag.
 102 static cl::opt<bool> ClCreatePCTable("sanitizer-coverage-pc-table",
 103                                      cl::desc("create a static PC table"),
 104                                      cl::Hidden, cl::init(false));
 105
 106 static cl::opt<bool>
 107     ClInline8bitCounters("sanitizer-coverage-inline-8bit-counters",
 108                          cl::desc("increments 8-bit counter for every edge"),
 109                          cl::Hidden, cl::init(false));
 110
 111 static cl::opt<bool>
 112     ClInlineBoolFlag("sanitizer-coverage-inline-bool-flag",
 113                      cl::desc("sets a boolean flag for every edge"), cl::Hidden,
 114                      cl::init(false));
 115
 116 static cl::opt<bool>
 117     ClCMPTracing("sanitizer-coverage-trace-compares",
 118                  cl::desc("Tracing of CMP and similar instructions"),
 119                  cl::Hidden, cl::init(false));
 120
 121 static cl::opt<bool> ClDIVTracing("sanitizer-coverage-trace-divs",
 122                                   cl::desc("Tracing of DIV instructions"),
 123                                   cl::Hidden, cl::init(false));
 124
 125 static cl::opt<bool> ClGEPTracing("sanitizer-coverage-trace-geps",
 126                                   cl::desc("Tracing of GEP instructions"),
 127                                   cl::Hidden, cl::init(false));
 128
 129 static cl::opt<bool>
 130     ClPruneBlocks("sanitizer-coverage-prune-blocks",
 131                   cl::desc("Reduce the number of instrumented blocks"),
 132                   cl::Hidden, cl::init(true));
 133
 134 static cl::opt<bool> ClStackDepth("sanitizer-coverage-stack-depth",
 135                                   cl::desc("max stack depth tracing"),
 136                                   cl::Hidden, cl::init(false));
 137
 138 namespace {
 139
 140 SanitizerCoverageOptions getOptions(int LegacyCoverageLevel) {
 141   SanitizerCoverageOptions Res;
 142   switch (LegacyCoverageLevel) {
 143   case 0:
 144     Res.CoverageType = SanitizerCoverageOptions::SCK_None;
 145     break;
 146   case 1:
 147     Res.CoverageType = SanitizerCoverageOptions::SCK_Function;
 148     break;
 149   case 2:
 150     Res.CoverageType = SanitizerCoverageOptions::SCK_BB;
 151     break;
 152   case 3:
 153     Res.CoverageType = SanitizerCoverageOptions::SCK_Edge;
 154     break;
 155   case 4:
 156     Res.CoverageType = SanitizerCoverageOptions::SCK_Edge;
 157     Res.IndirectCalls = true;
 158     break;
 159   }
 160   return Res;
 161 }
 162
 163 SanitizerCoverageOptions OverrideFromCL(SanitizerCoverageOptions Options) {
 164   // Sets CoverageType and IndirectCalls.
 165   SanitizerCoverageOptions CLOpts = getOptions(ClCoverageLevel);
 166   Options.CoverageType = std::max(Options.CoverageType, CLOpts.CoverageType);
 167   Options.IndirectCalls |= CLOpts.IndirectCalls;
 168   Options.TraceCmp |= ClCMPTracing;
 169   Options.TraceDiv |= ClDIVTracing;
 170   Options.TraceGep |= ClGEPTracing;
 171   Options.TracePC |= ClTracePC;
 172   Options.TracePCGuard |= ClTracePCGuard;
 173   Options.Inline8bitCounters |= ClInline8bitCounters;
 174   Options.InlineBoolFlag |= ClInlineBoolFlag;
 175   Options.PCTable |= ClCreatePCTable;
 176   Options.NoPrune |= !ClPruneBlocks;
 177   Options.StackDepth |= ClStackDepth;
 178   if (!Options.TracePCGuard && !Options.TracePC &&
 179       !Options.Inline8bitCounters && !Options.StackDepth &&
 180       !Options.InlineBoolFlag)
 181     Options.TracePCGuard = true; // TracePCGuard is default.
 182   return Options;
 183 }
 184
 185 using DomTreeCallback = function_ref<const DominatorTree *(Function &F)>;
 186 using PostDomTreeCallback =
 187     function_ref<const PostDominatorTree *(Function &F)>;
 188
 189 class ModuleSanitizerCoverage {
 190 public:
 191   ModuleSanitizerCoverage(
 192       const SanitizerCoverageOptions &Options = SanitizerCoverageOptions(),
 193       const SpecialCaseList *Allowlist = nullptr,
 194       const SpecialCaseList *Blocklist = nullptr)
 195       : Options(OverrideFromCL(Options)), Allowlist(Allowlist),
 196         Blocklist(Blocklist) {}
 197   bool instrumentModule(Module &M, DomTreeCallback DTCallback,
 198                         PostDomTreeCallback PDTCallback);
 199
 200 private:
 201   void instrumentFunction(Function &F, DomTreeCallback DTCallback,
 202                           PostDomTreeCallback PDTCallback);
 203   void InjectCoverageForIndirectCalls(Function &F,
 204                                       ArrayRef<Instruction *> IndirCalls);
 205   void InjectTraceForCmp(Function &F, ArrayRef<Instruction *> CmpTraceTargets);
 206   void InjectTraceForDiv(Function &F,
 207                          ArrayRef<BinaryOperator *> DivTraceTargets);
 208   void InjectTraceForGep(Function &F,
 209                          ArrayRef<GetElementPtrInst *> GepTraceTargets);
 210   void InjectTraceForSwitch(Function &F,
 211                             ArrayRef<Instruction *> SwitchTraceTargets);
 212   bool InjectCoverage(Function &F, ArrayRef<BasicBlock *> AllBlocks,
 213                       bool IsLeafFunc = true);
 214   GlobalVariable *CreateFunctionLocalArrayInSection(size_t NumElements,
 215                                                     Function &F, Type *Ty,
 216                                                     const char *Section);
 217   GlobalVariable *CreatePCArray(Function &F, ArrayRef<BasicBlock *> AllBlocks);
 218   void CreateFunctionLocalArrays(Function &F, ArrayRef<BasicBlock *> AllBlocks);
 219   void InjectCoverageAtBlock(Function &F, BasicBlock &BB, size_t Idx,
 220                              bool IsLeafFunc = true);
 221   Function *CreateInitCallsForSections(Module &M, const char *CtorName,
 222                                        const char *InitFunctionName, Type *Ty,
 223                                        const char *Section);
 224   std::pair<Value *, Value *> CreateSecStartEnd(Module &M, const char *Section,
 225                                                 Type *Ty);
 226
 227   void SetNoSanitizeMetadata(Instruction *I) {
 228     I->setMetadata(I->getModule()->getMDKindID("nosanitize"),
 229                    MDNode::get(*C, None));
 230   }
 231
 232   std::string getSectionName(const std::string &Section) const;
 233   std::string getSectionStart(const std::string &Section) const;
 234   std::string getSectionEnd(const std::string &Section) const;
 235   FunctionCallee SanCovTracePCIndir;
 236   FunctionCallee SanCovTracePC, SanCovTracePCGuard;
 237   FunctionCallee SanCovTraceCmpFunction[4];
 238   FunctionCallee SanCovTraceConstCmpFunction[4];
 239   FunctionCallee SanCovTraceDivFunction[2];
 240   FunctionCallee SanCovTraceGepFunction;
 241   FunctionCallee SanCovTraceSwitchFunction;
 242   GlobalVariable *SanCovLowestStack;
 243   Type *IntptrTy, *IntptrPtrTy, *Int64Ty, *Int64PtrTy, *Int32Ty, *Int32PtrTy,
 244       *Int16Ty, *Int8Ty, *Int8PtrTy, *Int1Ty, *Int1PtrTy;
 245   Module *CurModule;
 246   std::string CurModuleUniqueId;
 247   Triple TargetTriple;
 248   LLVMContext *C;
 249   const DataLayout *DL;
 250
 251   GlobalVariable *FunctionGuardArray;  // for trace-pc-guard.
 252   GlobalVariable *Function8bitCounterArray;  // for inline-8bit-counters.
 253   GlobalVariable *FunctionBoolArray;         // for inline-bool-flag.
 254   GlobalVariable *FunctionPCsArray;  // for pc-table.
 255   SmallVector<GlobalValue *, 20> GlobalsToAppendToUsed;
 256   SmallVector<GlobalValue *, 20> GlobalsToAppendToCompilerUsed;
 257
 258   SanitizerCoverageOptions Options;
 259
 260   const SpecialCaseList *Allowlist;
 261   const SpecialCaseList *Blocklist;
 262 };
 263
 264 class ModuleSanitizerCoverageLegacyPass : public ModulePass {
 265 public:
 266   ModuleSanitizerCoverageLegacyPass(
 267       const SanitizerCoverageOptions &Options = SanitizerCoverageOptions(),
 268       const std::vector<std::string> &AllowlistFiles =
 269           std::vector<std::string>(),
 270       const std::vector<std::string> &BlocklistFiles =
 271           std::vector<std::string>())
 272       : ModulePass(ID), Options(Options) {
 273     if (AllowlistFiles.size() > 0)
 274       Allowlist = SpecialCaseList::createOrDie(AllowlistFiles,
 275                                                *vfs::getRealFileSystem());
 276     if (BlocklistFiles.size() > 0)
 277       Blocklist = SpecialCaseList::createOrDie(BlocklistFiles,
 278                                                *vfs::getRealFileSystem());
 279     initializeModuleSanitizerCoverageLegacyPassPass(
 280         *PassRegistry::getPassRegistry());
 281   }
 282   bool runOnModule(Module &M) override {
 283     ModuleSanitizerCoverage ModuleSancov(Options, Allowlist.get(),
 284                                          Blocklist.get());
 285     auto DTCallback = [this](Function &F) -> const DominatorTree * {
 286       return &this->getAnalysis<DominatorTreeWrapperPass>(F).getDomTree();
 287     };
 288     auto PDTCallback = [this](Function &F) -> const PostDominatorTree * {
 289       return &this->getAnalysis<PostDominatorTreeWrapperPass>(F)
 290                   .getPostDomTree();
 291     };
 292     return ModuleSancov.instrumentModule(M, DTCallback, PDTCallback);
 293   }
 294
 295   static char ID; // Pass identification, replacement for typeid
 296   StringRef getPassName() const override { return "ModuleSanitizerCoverage"; }
 297
 298   void getAnalysisUsage(AnalysisUsage &AU) const override {
 299     AU.addRequired<DominatorTreeWrapperPass>();
 300     AU.addRequired<PostDominatorTreeWrapperPass>();
 301   }
 302
 303 private:
 304   SanitizerCoverageOptions Options;
 305
 306   std::unique_ptr<SpecialCaseList> Allowlist;
 307   std::unique_ptr<SpecialCaseList> Blocklist;
 308 };
 309
 310 } // namespace
 311
 312 PreservedAnalyses ModuleSanitizerCoveragePass::run(Module &M,
 313                                                    ModuleAnalysisManager &MAM) {
 314   ModuleSanitizerCoverage ModuleSancov(Options, Allowlist.get(),
 315                                        Blocklist.get());
 316   auto &FAM = MAM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
 317   auto DTCallback = [&FAM](Function &F) -> const DominatorTree * {
 318     return &FAM.getResult<DominatorTreeAnalysis>(F);
 319   };
 320   auto PDTCallback = [&FAM](Function &F) -> const PostDominatorTree * {
 321     return &FAM.getResult<PostDominatorTreeAnalysis>(F);
 322   };
 323   if (ModuleSancov.instrumentModule(M, DTCallback, PDTCallback))
 324     return PreservedAnalyses::none();
 325   return PreservedAnalyses::all();
 326 }
 327
 328 std::pair<Value *, Value *>
 329 ModuleSanitizerCoverage::CreateSecStartEnd(Module &M, const char *Section,
 330                                            Type *Ty) {
 331   // Use ExternalWeak so that if all sections are discarded due to section
 332   // garbage collection, the linker will not report undefined symbol errors.
 333   // Windows defines the start/stop symbols in compiler-rt so no need for
 334   // ExternalWeak.
 335   GlobalValue::LinkageTypes Linkage = TargetTriple.isOSBinFormatCOFF()
 336                                           ? GlobalVariable::ExternalLinkage
 337                                           : GlobalVariable::ExternalWeakLinkage;
 338   GlobalVariable *SecStart =
 339       new GlobalVariable(M, Ty, false, Linkage, nullptr,
 340                          getSectionStart(Section));
 341   SecStart->setVisibility(GlobalValue::HiddenVisibility);
 342   GlobalVariable *SecEnd =
 343       new GlobalVariable(M, Ty, false, Linkage, nullptr,
 344                          getSectionEnd(Section));
 345   SecEnd->setVisibility(GlobalValue::HiddenVisibility);
 346   IRBuilder<> IRB(M.getContext());
 347   if (!TargetTriple.isOSBinFormatCOFF())
 348     return std::make_pair(SecStart, SecEnd);
 349
 350   // Account for the fact that on windows-msvc __start_* symbols actually
 351   // point to a uint64_t before the start of the array.
 352   auto SecStartI8Ptr = IRB.CreatePointerCast(SecStart, Int8PtrTy);
 353   auto GEP = IRB.CreateGEP(Int8Ty, SecStartI8Ptr,
 354                            ConstantInt::get(IntptrTy, sizeof(uint64_t)));
 355   return std::make_pair(IRB.CreatePointerCast(GEP, PointerType::getUnqual(Ty)),
 356                         SecEnd);
 357 }
 358
 359 Function *ModuleSanitizerCoverage::CreateInitCallsForSections(
 360     Module &M, const char *CtorName, const char *InitFunctionName, Type *Ty,
 361     const char *Section) {
 362   auto SecStartEnd = CreateSecStartEnd(M, Section, Ty);
 363   auto SecStart = SecStartEnd.first;
 364   auto SecEnd = SecStartEnd.second;
 365   Function *CtorFunc;
 366   Type *PtrTy = PointerType::getUnqual(Ty);
 367   std::tie(CtorFunc, std::ignore) = createSanitizerCtorAndInitFunctions(
 368       M, CtorName, InitFunctionName, {PtrTy, PtrTy}, {SecStart, SecEnd});
 369   assert(CtorFunc->getName() == CtorName);
 370
 371   if (TargetTriple.supportsCOMDAT()) {
 372     // Use comdat to dedup CtorFunc.
 373     CtorFunc->setComdat(M.getOrInsertComdat(CtorName));
 374     appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority, CtorFunc);
 375   } else {
 376     appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority);
 377   }
 378
 379   if (TargetTriple.isOSBinFormatCOFF()) {
 380     // In COFF files, if the contructors are set as COMDAT (they are because
 381     // COFF supports COMDAT) and the linker flag /OPT:REF (strip unreferenced
 382     // functions and data) is used, the constructors get stripped. To prevent
 383     // this, give the constructors weak ODR linkage and ensure the linker knows
 384     // to include the sancov constructor. This way the linker can deduplicate
 385     // the constructors but always leave one copy.
 386     CtorFunc->setLinkage(GlobalValue::WeakODRLinkage);
 387   }
 388   return CtorFunc;
 389 }
 390
 391 bool ModuleSanitizerCoverage::instrumentModule(
 392     Module &M, DomTreeCallback DTCallback, PostDomTreeCallback PDTCallback) {
 393   if (Options.CoverageType == SanitizerCoverageOptions::SCK_None)
 394     return false;
 395   if (Allowlist &&
 396       !Allowlist->inSection("coverage", "src", M.getSourceFileName()))
 397     return false;
 398   if (Blocklist &&
 399       Blocklist->inSection("coverage", "src", M.getSourceFileName()))
 400     return false;
 401   C = &(M.getContext());
 402   DL = &M.getDataLayout();
 403   CurModule = &M;
 404   CurModuleUniqueId = getUniqueModuleId(CurModule);
 405   TargetTriple = Triple(M.getTargetTriple());
 406   FunctionGuardArray = nullptr;
 407   Function8bitCounterArray = nullptr;
 408   FunctionBoolArray = nullptr;
 409   FunctionPCsArray = nullptr;
 410   IntptrTy = Type::getIntNTy(*C, DL->getPointerSizeInBits());
 411   IntptrPtrTy = PointerType::getUnqual(IntptrTy);
 412   Type *VoidTy = Type::getVoidTy(*C);
 413   IRBuilder<> IRB(*C);
 414   Int64PtrTy = PointerType::getUnqual(IRB.getInt64Ty());
 415   Int32PtrTy = PointerType::getUnqual(IRB.getInt32Ty());
 416   Int8PtrTy = PointerType::getUnqual(IRB.getInt8Ty());
 417   Int1PtrTy = PointerType::getUnqual(IRB.getInt1Ty());
 418   Int64Ty = IRB.getInt64Ty();
 419   Int32Ty = IRB.getInt32Ty();
 420   Int16Ty = IRB.getInt16Ty();
 421   Int8Ty = IRB.getInt8Ty();
 422   Int1Ty = IRB.getInt1Ty();
 423
 424   SanCovTracePCIndir =
 425       M.getOrInsertFunction(SanCovTracePCIndirName, VoidTy, IntptrTy);
 426   // Make sure smaller parameters are zero-extended to i64 if required by the
 427   // target ABI.
 428   AttributeList SanCovTraceCmpZeroExtAL;
 429   SanCovTraceCmpZeroExtAL =
 430       SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 0, Attribute::ZExt);
 431   SanCovTraceCmpZeroExtAL =
 432       SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 1, Attribute::ZExt);
 433
 434   SanCovTraceCmpFunction[0] =
 435       M.getOrInsertFunction(SanCovTraceCmp1, SanCovTraceCmpZeroExtAL, VoidTy,
 436                             IRB.getInt8Ty(), IRB.getInt8Ty());
 437   SanCovTraceCmpFunction[1] =
 438       M.getOrInsertFunction(SanCovTraceCmp2, SanCovTraceCmpZeroExtAL, VoidTy,
 439                             IRB.getInt16Ty(), IRB.getInt16Ty());
 440   SanCovTraceCmpFunction[2] =
 441       M.getOrInsertFunction(SanCovTraceCmp4, SanCovTraceCmpZeroExtAL, VoidTy,
 442                             IRB.getInt32Ty(), IRB.getInt32Ty());
 443   SanCovTraceCmpFunction[3] =
 444       M.getOrInsertFunction(SanCovTraceCmp8, VoidTy, Int64Ty, Int64Ty);
 445
 446   SanCovTraceConstCmpFunction[0] = M.getOrInsertFunction(
 447       SanCovTraceConstCmp1, SanCovTraceCmpZeroExtAL, VoidTy, Int8Ty, Int8Ty);
 448   SanCovTraceConstCmpFunction[1] = M.getOrInsertFunction(
 449       SanCovTraceConstCmp2, SanCovTraceCmpZeroExtAL, VoidTy, Int16Ty, Int16Ty);
 450   SanCovTraceConstCmpFunction[2] = M.getOrInsertFunction(
 451       SanCovTraceConstCmp4, SanCovTraceCmpZeroExtAL, VoidTy, Int32Ty, Int32Ty);
 452   SanCovTraceConstCmpFunction[3] =
 453       M.getOrInsertFunction(SanCovTraceConstCmp8, VoidTy, Int64Ty, Int64Ty);
 454
 455   {
 456     AttributeList AL;
 457     AL = AL.addParamAttribute(*C, 0, Attribute::ZExt);
 458     SanCovTraceDivFunction[0] =
 459         M.getOrInsertFunction(SanCovTraceDiv4, AL, VoidTy, IRB.getInt32Ty());
 460   }
 461   SanCovTraceDivFunction[1] =
 462       M.getOrInsertFunction(SanCovTraceDiv8, VoidTy, Int64Ty);
 463   SanCovTraceGepFunction =
 464       M.getOrInsertFunction(SanCovTraceGep, VoidTy, IntptrTy);
 465   SanCovTraceSwitchFunction =
 466       M.getOrInsertFunction(SanCovTraceSwitchName, VoidTy, Int64Ty, Int64PtrTy);
 467
 468   Constant *SanCovLowestStackConstant =
 469       M.getOrInsertGlobal(SanCovLowestStackName, IntptrTy);
 470   SanCovLowestStack = dyn_cast<GlobalVariable>(SanCovLowestStackConstant);
 471   if (!SanCovLowestStack || SanCovLowestStack->getValueType() != IntptrTy) {
 472     C->emitError(StringRef("'") + SanCovLowestStackName +
 473                  "' should not be declared by the user");
 474     return true;
 475   }
 476   SanCovLowestStack->setThreadLocalMode(
 477       GlobalValue::ThreadLocalMode::InitialExecTLSModel);
 478   if (Options.StackDepth && !SanCovLowestStack->isDeclaration())
 479     SanCovLowestStack->setInitializer(Constant::getAllOnesValue(IntptrTy));
 480
 481   SanCovTracePC = M.getOrInsertFunction(SanCovTracePCName, VoidTy);
 482   SanCovTracePCGuard =
 483       M.getOrInsertFunction(SanCovTracePCGuardName, VoidTy, Int32PtrTy);
 484
 485   for (auto &F : M)
 486     instrumentFunction(F, DTCallback, PDTCallback);
 487
 488   Function *Ctor = nullptr;
 489
 490   if (FunctionGuardArray)
 491     Ctor = CreateInitCallsForSections(M, SanCovModuleCtorTracePcGuardName,
 492                                       SanCovTracePCGuardInitName, Int32Ty,
 493                                       SanCovGuardsSectionName);
 494   if (Function8bitCounterArray)
 495     Ctor = CreateInitCallsForSections(M, SanCovModuleCtor8bitCountersName,
 496                                       SanCov8bitCountersInitName, Int8Ty,
 497                                       SanCovCountersSectionName);
 498   if (FunctionBoolArray) {
 499     Ctor = CreateInitCallsForSections(M, SanCovModuleCtorBoolFlagName,
 500                                       SanCovBoolFlagInitName, Int1Ty,
 501                                       SanCovBoolFlagSectionName);
 502   }
 503   if (Ctor && Options.PCTable) {
 504     auto SecStartEnd = CreateSecStartEnd(M, SanCovPCsSectionName, IntptrTy);
 505     FunctionCallee InitFunction = declareSanitizerInitFunction(
 506         M, SanCovPCsInitName, {IntptrPtrTy, IntptrPtrTy});
 507     IRBuilder<> IRBCtor(Ctor->getEntryBlock().getTerminator());
 508     IRBCtor.CreateCall(InitFunction, {SecStartEnd.first, SecStartEnd.second});
 509   }
 510   appendToUsed(M, GlobalsToAppendToUsed);
 511   appendToCompilerUsed(M, GlobalsToAppendToCompilerUsed);
 512   return true;
 513 }
 514
 515 // True if block has successors and it dominates all of them.
 516 static bool isFullDominator(const BasicBlock *BB, const DominatorTree *DT) {
 517   if (succ_empty(BB))
 518     return false;
 519
 520   return llvm::all_of(successors(BB), [&](const BasicBlock *SUCC) {
 521     return DT->dominates(BB, SUCC);
 522   });
 523 }
 524
 525 // True if block has predecessors and it postdominates all of them.
 526 static bool isFullPostDominator(const BasicBlock *BB,
 527                                 const PostDominatorTree *PDT) {
 528   if (pred_empty(BB))
 529     return false;
 530
 531   return llvm::all_of(predecessors(BB), [&](const BasicBlock *PRED) {
 532     return PDT->dominates(BB, PRED);
 533   });
 534 }
 535
 536 static bool shouldInstrumentBlock(const Function &F, const BasicBlock *BB,
 537                                   const DominatorTree *DT,
 538                                   const PostDominatorTree *PDT,
 539                                   const SanitizerCoverageOptions &Options) {
 540   // Don't insert coverage for blocks containing nothing but unreachable: we
 541   // will never call __sanitizer_cov() for them, so counting them in
 542   // NumberOfInstrumentedBlocks() might complicate calculation of code coverage
 543   // percentage. Also, unreachable instructions frequently have no debug
 544   // locations.
 545   if (isa<UnreachableInst>(BB->getFirstNonPHIOrDbgOrLifetime()))
 546     return false;
 547
 548   // Don't insert coverage into blocks without a valid insertion point
 549   // (catchswitch blocks).
 550   if (BB->getFirstInsertionPt() == BB->end())
 551     return false;
 552
 553   if (Options.NoPrune || &F.getEntryBlock() == BB)
 554     return true;
 555
 556   if (Options.CoverageType == SanitizerCoverageOptions::SCK_Function &&
 557       &F.getEntryBlock() != BB)
 558     return false;
 559
 560   // Do not instrument full dominators, or full post-dominators with multiple
 561   // predecessors.
 562   return !isFullDominator(BB, DT)
 563     && !(isFullPostDominator(BB, PDT) && !BB->getSinglePredecessor());
 564 }
 565
 566
 567 // Returns true iff From->To is a backedge.
 568 // A twist here is that we treat From->To as a backedge if
 569 //   * To dominates From or
 570 //   * To->UniqueSuccessor dominates From
 571 static bool IsBackEdge(BasicBlock *From, BasicBlock *To,
 572                        const DominatorTree *DT) {
 573   if (DT->dominates(To, From))
 574     return true;
 575   if (auto Next = To->getUniqueSuccessor())
 576     if (DT->dominates(Next, From))
 577       return true;
 578   return false;
 579 }
 580
 581 // Prunes uninteresting Cmp instrumentation:
 582 //   * CMP instructions that feed into loop backedge branch.
 583 //
 584 // Note that Cmp pruning is controlled by the same flag as the
 585 // BB pruning.
 586 static bool IsInterestingCmp(ICmpInst *CMP, const DominatorTree *DT,
 587                              const SanitizerCoverageOptions &Options) {
 588   if (!Options.NoPrune)
 589     if (CMP->hasOneUse())
 590       if (auto BR = dyn_cast<BranchInst>(CMP->user_back()))
 591         for (BasicBlock *B : BR->successors())
 592           if (IsBackEdge(BR->getParent(), B, DT))
 593             return false;
 594   return true;
 595 }
 596
 597 void ModuleSanitizerCoverage::instrumentFunction(
 598     Function &F, DomTreeCallback DTCallback, PostDomTreeCallback PDTCallback) {
 599   if (F.empty())
 600     return;
 601   if (F.getName().find(".module_ctor") != std::string::npos)
 602     return; // Should not instrument sanitizer init functions.
 603   if (F.getName().startswith("__sanitizer_"))
 604     return; // Don't instrument __sanitizer_* callbacks.
 605   // Don't touch available_externally functions, their actual body is elewhere.
 606   if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage)
 607     return;
 608   // Don't instrument MSVC CRT configuration helpers. They may run before normal
 609   // initialization.
 610   if (F.getName() == "__local_stdio_printf_options" ||
 611       F.getName() == "__local_stdio_scanf_options")
 612     return;
 613   if (isa<UnreachableInst>(F.getEntryBlock().getTerminator()))
 614     return;
 615   // Don't instrument functions using SEH for now. Splitting basic blocks like
 616   // we do for coverage breaks WinEHPrepare.
 617   // FIXME: Remove this when SEH no longer uses landingpad pattern matching.
 618   if (F.hasPersonalityFn() &&
 619       isAsynchronousEHPersonality(classifyEHPersonality(F.getPersonalityFn())))
 620     return;
 621   if (Allowlist && !Allowlist->inSection("coverage", "fun", F.getName()))
 622     return;
 623   if (Blocklist && Blocklist->inSection("coverage", "fun", F.getName()))
 624     return;
 625   if (F.hasFnAttribute(Attribute::NoSanitizeCoverage))
 626     return;
 627   if (Options.CoverageType >= SanitizerCoverageOptions::SCK_Edge)
 628     SplitAllCriticalEdges(F, CriticalEdgeSplittingOptions().setIgnoreUnreachableDests());
 629   SmallVector<Instruction *, 8> IndirCalls;
 630   SmallVector<BasicBlock *, 16> BlocksToInstrument;
 631   SmallVector<Instruction *, 8> CmpTraceTargets;
 632   SmallVector<Instruction *, 8> SwitchTraceTargets;
 633   SmallVector<BinaryOperator *, 8> DivTraceTargets;
 634   SmallVector<GetElementPtrInst *, 8> GepTraceTargets;
 635
 636   const DominatorTree *DT = DTCallback(F);
 637   const PostDominatorTree *PDT = PDTCallback(F);
 638   bool IsLeafFunc = true;
 639
 640   for (auto &BB : F) {
 641     if (shouldInstrumentBlock(F, &BB, DT, PDT, Options))
 642       BlocksToInstrument.push_back(&BB);
 643     for (auto &Inst : BB) {
 644       if (Options.IndirectCalls) {
 645         CallBase *CB = dyn_cast<CallBase>(&Inst);
 646         if (CB && !CB->getCalledFunction())
 647           IndirCalls.push_back(&Inst);
 648       }
 649       if (Options.TraceCmp) {
 650         if (ICmpInst *CMP = dyn_cast<ICmpInst>(&Inst))
 651           if (IsInterestingCmp(CMP, DT, Options))
 652             CmpTraceTargets.push_back(&Inst);
 653         if (isa<SwitchInst>(&Inst))
 654           SwitchTraceTargets.push_back(&Inst);
 655       }
 656       if (Options.TraceDiv)
 657         if (BinaryOperator *BO = dyn_cast<BinaryOperator>(&Inst))
 658           if (BO->getOpcode() == Instruction::SDiv ||
 659               BO->getOpcode() == Instruction::UDiv)
 660             DivTraceTargets.push_back(BO);
 661       if (Options.TraceGep)
 662         if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(&Inst))
 663           GepTraceTargets.push_back(GEP);
 664       if (Options.StackDepth)
 665         if (isa<InvokeInst>(Inst) ||
 666             (isa<CallInst>(Inst) && !isa<IntrinsicInst>(Inst)))
 667           IsLeafFunc = false;
 668     }
 669   }
 670
 671   InjectCoverage(F, BlocksToInstrument, IsLeafFunc);
 672   InjectCoverageForIndirectCalls(F, IndirCalls);
 673   InjectTraceForCmp(F, CmpTraceTargets);
 674   InjectTraceForSwitch(F, SwitchTraceTargets);
 675   InjectTraceForDiv(F, DivTraceTargets);
 676   InjectTraceForGep(F, GepTraceTargets);
 677 }
 678
 679 GlobalVariable *ModuleSanitizerCoverage::CreateFunctionLocalArrayInSection(
 680     size_t NumElements, Function &F, Type *Ty, const char *Section) {
 681   ArrayType *ArrayTy = ArrayType::get(Ty, NumElements);
 682   auto Array = new GlobalVariable(
 683       *CurModule, ArrayTy, false, GlobalVariable::PrivateLinkage,
 684       Constant::getNullValue(ArrayTy), "__sancov_gen_");
 685
 686   if (TargetTriple.supportsCOMDAT() &&
 687       (TargetTriple.isOSBinFormatELF() || !F.isInterposable()))
 688     if (auto Comdat = getOrCreateFunctionComdat(F, TargetTriple))
 689       Array->setComdat(Comdat);
 690   Array->setSection(getSectionName(Section));
 691   Array->setAlignment(Align(DL->getTypeStoreSize(Ty).getFixedSize()));
 692
 693   // sancov_pcs parallels the other metadata section(s). Optimizers (e.g.
 694   // GlobalOpt/ConstantMerge) may not discard sancov_pcs and the other
 695   // section(s) as a unit, so we conservatively retain all unconditionally in
 696   // the compiler.
 697   //
 698   // With comdat (COFF/ELF), the linker can guarantee the associated sections
 699   // will be retained or discarded as a unit, so llvm.compiler.used is
 700   // sufficient. Otherwise, conservatively make all of them retained by the
 701   // linker.
 702   if (Array->hasComdat())
 703     GlobalsToAppendToCompilerUsed.push_back(Array);
 704   else
 705     GlobalsToAppendToUsed.push_back(Array);
 706
 707   return Array;
 708 }
 709
 710 GlobalVariable *
 711 ModuleSanitizerCoverage::CreatePCArray(Function &F,
 712                                        ArrayRef<BasicBlock *> AllBlocks) {
 713   size_t N = AllBlocks.size();
 714   assert(N);
 715   SmallVector<Constant *, 32> PCs;
 716   IRBuilder<> IRB(&*F.getEntryBlock().getFirstInsertionPt());
 717   for (size_t i = 0; i < N; i++) {
 718     if (&F.getEntryBlock() == AllBlocks[i]) {
 719       PCs.push_back((Constant *)IRB.CreatePointerCast(&F, IntptrPtrTy));
 720       PCs.push_back((Constant *)IRB.CreateIntToPtr(
 721           ConstantInt::get(IntptrTy, 1), IntptrPtrTy));
 722     } else {
 723       PCs.push_back((Constant *)IRB.CreatePointerCast(
 724           BlockAddress::get(AllBlocks[i]), IntptrPtrTy));
 725       PCs.push_back((Constant *)IRB.CreateIntToPtr(
 726           ConstantInt::get(IntptrTy, 0), IntptrPtrTy));
 727     }
 728   }
 729   auto *PCArray = CreateFunctionLocalArrayInSection(N * 2, F, IntptrPtrTy,
 730                                                     SanCovPCsSectionName);
 731   PCArray->setInitializer(
 732       ConstantArray::get(ArrayType::get(IntptrPtrTy, N * 2), PCs));
 733   PCArray->setConstant(true);
 734
 735   return PCArray;
 736 }
 737
 738 void ModuleSanitizerCoverage::CreateFunctionLocalArrays(
 739     Function &F, ArrayRef<BasicBlock *> AllBlocks) {
 740   if (Options.TracePCGuard)
 741     FunctionGuardArray = CreateFunctionLocalArrayInSection(
 742         AllBlocks.size(), F, Int32Ty, SanCovGuardsSectionName);
 743
 744   if (Options.Inline8bitCounters)
 745     Function8bitCounterArray = CreateFunctionLocalArrayInSection(
 746         AllBlocks.size(), F, Int8Ty, SanCovCountersSectionName);
 747   if (Options.InlineBoolFlag)
 748     FunctionBoolArray = CreateFunctionLocalArrayInSection(
 749         AllBlocks.size(), F, Int1Ty, SanCovBoolFlagSectionName);
 750
 751   if (Options.PCTable)
 752     FunctionPCsArray = CreatePCArray(F, AllBlocks);
 753 }
 754
 755 bool ModuleSanitizerCoverage::InjectCoverage(Function &F,
 756                                              ArrayRef<BasicBlock *> AllBlocks,
 757                                              bool IsLeafFunc) {
 758   if (AllBlocks.empty()) return false;
 759   CreateFunctionLocalArrays(F, AllBlocks);
 760   for (size_t i = 0, N = AllBlocks.size(); i < N; i++)
 761     InjectCoverageAtBlock(F, *AllBlocks[i], i, IsLeafFunc);
 762   return true;
 763 }
 764
 765 // On every indirect call we call a run-time function
 766 // __sanitizer_cov_indir_call* with two parameters:
 767 //   - callee address,
 768 //   - global cache array that contains CacheSize pointers (zero-initialized).
 769 //     The cache is used to speed up recording the caller-callee pairs.
 770 // The address of the caller is passed implicitly via caller PC.
 771 // CacheSize is encoded in the name of the run-time function.
 772 void ModuleSanitizerCoverage::InjectCoverageForIndirectCalls(
 773     Function &F, ArrayRef<Instruction *> IndirCalls) {
 774   if (IndirCalls.empty())
 775     return;
 776   assert(Options.TracePC || Options.TracePCGuard ||
 777          Options.Inline8bitCounters || Options.InlineBoolFlag);
 778   for (auto I : IndirCalls) {
 779     IRBuilder<> IRB(I);
 780     CallBase &CB = cast<CallBase>(*I);
 781     Value *Callee = CB.getCalledOperand();
 782     if (isa<InlineAsm>(Callee))
 783       continue;
 784     IRB.CreateCall(SanCovTracePCIndir, IRB.CreatePointerCast(Callee, IntptrTy));
 785   }
 786 }
 787
 788 // For every switch statement we insert a call:
 789 // __sanitizer_cov_trace_switch(CondValue,
 790 //      {NumCases, ValueSizeInBits, Case0Value, Case1Value, Case2Value, ... })
 791
 792 void ModuleSanitizerCoverage::InjectTraceForSwitch(
 793     Function &, ArrayRef<Instruction *> SwitchTraceTargets) {
 794   for (auto I : SwitchTraceTargets) {
 795     if (SwitchInst *SI = dyn_cast<SwitchInst>(I)) {
 796       IRBuilder<> IRB(I);
 797       SmallVector<Constant *, 16> Initializers;
 798       Value *Cond = SI->getCondition();
 799       if (Cond->getType()->getScalarSizeInBits() >
 800           Int64Ty->getScalarSizeInBits())
 801         continue;
 802       Initializers.push_back(ConstantInt::get(Int64Ty, SI->getNumCases()));
 803       Initializers.push_back(
 804           ConstantInt::get(Int64Ty, Cond->getType()->getScalarSizeInBits()));
 805       if (Cond->getType()->getScalarSizeInBits() <
 806           Int64Ty->getScalarSizeInBits())
 807         Cond = IRB.CreateIntCast(Cond, Int64Ty, false);
 808       for (auto It : SI->cases()) {
 809         Constant *C = It.getCaseValue();
 810         if (C->getType()->getScalarSizeInBits() <
 811             Int64Ty->getScalarSizeInBits())
 812           C = ConstantExpr::getCast(CastInst::ZExt, It.getCaseValue(), Int64Ty);
 813         Initializers.push_back(C);
 814       }
 815       llvm::sort(drop_begin(Initializers, 2),
 816                  [](const Constant *A, const Constant *B) {
 817                    return cast<ConstantInt>(A)->getLimitedValue() <
 818                           cast<ConstantInt>(B)->getLimitedValue();
 819                  });
 820       ArrayType *ArrayOfInt64Ty = ArrayType::get(Int64Ty, Initializers.size());
 821       GlobalVariable *GV = new GlobalVariable(
 822           *CurModule, ArrayOfInt64Ty, false, GlobalVariable::InternalLinkage,
 823           ConstantArray::get(ArrayOfInt64Ty, Initializers),
 824           "__sancov_gen_cov_switch_values");
 825       IRB.CreateCall(SanCovTraceSwitchFunction,
 826                      {Cond, IRB.CreatePointerCast(GV, Int64PtrTy)});
 827     }
 828   }
 829 }
 830
 831 void ModuleSanitizerCoverage::InjectTraceForDiv(
 832     Function &, ArrayRef<BinaryOperator *> DivTraceTargets) {
 833   for (auto BO : DivTraceTargets) {
 834     IRBuilder<> IRB(BO);
 835     Value *A1 = BO->getOperand(1);
 836     if (isa<ConstantInt>(A1)) continue;
 837     if (!A1->getType()->isIntegerTy())
 838       continue;
 839     uint64_t TypeSize = DL->getTypeStoreSizeInBits(A1->getType());
 840     int CallbackIdx = TypeSize == 32 ? 0 :
 841         TypeSize == 64 ? 1 : -1;
 842     if (CallbackIdx < 0) continue;
 843     auto Ty = Type::getIntNTy(*C, TypeSize);
 844     IRB.CreateCall(SanCovTraceDivFunction[CallbackIdx],
 845                    {IRB.CreateIntCast(A1, Ty, true)});
 846   }
 847 }
 848
 849 void ModuleSanitizerCoverage::InjectTraceForGep(
 850     Function &, ArrayRef<GetElementPtrInst *> GepTraceTargets) {
 851   for (auto GEP : GepTraceTargets) {
 852     IRBuilder<> IRB(GEP);
 853     for (Use &Idx : GEP->indices())
 854       if (!isa<ConstantInt>(Idx) && Idx->getType()->isIntegerTy())
 855         IRB.CreateCall(SanCovTraceGepFunction,
 856                        {IRB.CreateIntCast(Idx, IntptrTy, true)});
 857   }
 858 }
 859
 860 void ModuleSanitizerCoverage::InjectTraceForCmp(
 861     Function &, ArrayRef<Instruction *> CmpTraceTargets) {
 862   for (auto I : CmpTraceTargets) {
 863     if (ICmpInst *ICMP = dyn_cast<ICmpInst>(I)) {
 864       IRBuilder<> IRB(ICMP);
 865       Value *A0 = ICMP->getOperand(0);
 866       Value *A1 = ICMP->getOperand(1);
 867       if (!A0->getType()->isIntegerTy())
 868         continue;
 869       uint64_t TypeSize = DL->getTypeStoreSizeInBits(A0->getType());
 870       int CallbackIdx = TypeSize == 8 ? 0 :
 871                         TypeSize == 16 ? 1 :
 872                         TypeSize == 32 ? 2 :
 873                         TypeSize == 64 ? 3 : -1;
 874       if (CallbackIdx < 0) continue;
 875       // __sanitizer_cov_trace_cmp((type_size << 32) | predicate, A0, A1);
 876       auto CallbackFunc = SanCovTraceCmpFunction[CallbackIdx];
 877       bool FirstIsConst = isa<ConstantInt>(A0);
 878       bool SecondIsConst = isa<ConstantInt>(A1);
 879       // If both are const, then we don't need such a comparison.
 880       if (FirstIsConst && SecondIsConst) continue;
 881       // If only one is const, then make it the first callback argument.
 882       if (FirstIsConst || SecondIsConst) {
 883         CallbackFunc = SanCovTraceConstCmpFunction[CallbackIdx];
 884         if (SecondIsConst)
 885           std::swap(A0, A1);
 886       }
 887
 888       auto Ty = Type::getIntNTy(*C, TypeSize);
 889       IRB.CreateCall(CallbackFunc, {IRB.CreateIntCast(A0, Ty, true),
 890               IRB.CreateIntCast(A1, Ty, true)});
 891     }
 892   }
 893 }
 894
 895 void ModuleSanitizerCoverage::InjectCoverageAtBlock(Function &F, BasicBlock &BB,
 896                                                     size_t Idx,
 897                                                     bool IsLeafFunc) {
 898   BasicBlock::iterator IP = BB.getFirstInsertionPt();
 899   bool IsEntryBB = &BB == &F.getEntryBlock();
 900   DebugLoc EntryLoc;
 901   if (IsEntryBB) {
 902     if (auto SP = F.getSubprogram())
 903       EntryLoc = DILocation::get(SP->getContext(), SP->getScopeLine(), 0, SP);
 904     // Keep static allocas and llvm.localescape calls in the entry block.  Even
 905     // if we aren't splitting the block, it's nice for allocas to be before
 906     // calls.
 907     IP = PrepareToSplitEntryBlock(BB, IP);
 908   } else {
 909     EntryLoc = IP->getDebugLoc();
 910     if (!EntryLoc)
 911       if (auto *SP = F.getSubprogram())
 912         EntryLoc = DILocation::get(SP->getContext(), 0, 0, SP);
 913   }
 914
 915   IRBuilder<> IRB(&*IP);
 916   IRB.SetCurrentDebugLocation(EntryLoc);
 917   if (Options.TracePC) {
 918     IRB.CreateCall(SanCovTracePC)
 919         ->setCannotMerge(); // gets the PC using GET_CALLER_PC.
 920   }
 921   if (Options.TracePCGuard) {
 922     auto GuardPtr = IRB.CreateIntToPtr(
 923         IRB.CreateAdd(IRB.CreatePointerCast(FunctionGuardArray, IntptrTy),
 924                       ConstantInt::get(IntptrTy, Idx * 4)),
 925         Int32PtrTy);
 926     IRB.CreateCall(SanCovTracePCGuard, GuardPtr)->setCannotMerge();
 927   }
 928   if (Options.Inline8bitCounters) {
 929     auto CounterPtr = IRB.CreateGEP(
 930         Function8bitCounterArray->getValueType(), Function8bitCounterArray,
 931         {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)});
 932     auto Load = IRB.CreateLoad(Int8Ty, CounterPtr);
 933     auto Inc = IRB.CreateAdd(Load, ConstantInt::get(Int8Ty, 1));
 934     auto Store = IRB.CreateStore(Inc, CounterPtr);
 935     SetNoSanitizeMetadata(Load);
 936     SetNoSanitizeMetadata(Store);
 937   }
 938   if (Options.InlineBoolFlag) {
 939     auto FlagPtr = IRB.CreateGEP(
 940         FunctionBoolArray->getValueType(), FunctionBoolArray,
 941         {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)});
 942     auto Load = IRB.CreateLoad(Int1Ty, FlagPtr);
 943     auto ThenTerm =
 944         SplitBlockAndInsertIfThen(IRB.CreateIsNull(Load), &*IP, false);
 945     IRBuilder<> ThenIRB(ThenTerm);
 946     auto Store = ThenIRB.CreateStore(ConstantInt::getTrue(Int1Ty), FlagPtr);
 947     SetNoSanitizeMetadata(Load);
 948     SetNoSanitizeMetadata(Store);
 949   }
 950   if (Options.StackDepth && IsEntryBB && !IsLeafFunc) {
 951     // Check stack depth.  If it's the deepest so far, record it.
 952     Module *M = F.getParent();
 953     Function *GetFrameAddr = Intrinsic::getDeclaration(
 954         M, Intrinsic::frameaddress,
 955         IRB.getInt8PtrTy(M->getDataLayout().getAllocaAddrSpace()));
 956     auto FrameAddrPtr =
 957         IRB.CreateCall(GetFrameAddr, {Constant::getNullValue(Int32Ty)});
 958     auto FrameAddrInt = IRB.CreatePtrToInt(FrameAddrPtr, IntptrTy);
 959     auto LowestStack = IRB.CreateLoad(IntptrTy, SanCovLowestStack);
 960     auto IsStackLower = IRB.CreateICmpULT(FrameAddrInt, LowestStack);
 961     auto ThenTerm = SplitBlockAndInsertIfThen(IsStackLower, &*IP, false);
 962     IRBuilder<> ThenIRB(ThenTerm);
 963     auto Store = ThenIRB.CreateStore(FrameAddrInt, SanCovLowestStack);
 964     SetNoSanitizeMetadata(LowestStack);
 965     SetNoSanitizeMetadata(Store);
 966   }
 967 }
 968
 969 std::string
 970 ModuleSanitizerCoverage::getSectionName(const std::string &Section) const {
 971   if (TargetTriple.isOSBinFormatCOFF()) {
 972     if (Section == SanCovCountersSectionName)
 973       return ".SCOV$CM";
 974     if (Section == SanCovBoolFlagSectionName)
 975       return ".SCOV$BM";
 976     if (Section == SanCovPCsSectionName)
 977       return ".SCOVP$M";
 978     return ".SCOV$GM"; // For SanCovGuardsSectionName.
 979   }
 980   if (TargetTriple.isOSBinFormatMachO())
 981     return "__DATA,__" + Section;
 982   return "__" + Section;
 983 }
 984
 985 std::string
 986 ModuleSanitizerCoverage::getSectionStart(const std::string &Section) const {
 987   if (TargetTriple.isOSBinFormatMachO())
 988     return "\1section$start$__DATA$__" + Section;
 989   return "__start___" + Section;
 990 }
 991
 992 std::string
 993 ModuleSanitizerCoverage::getSectionEnd(const std::string &Section) const {
 994   if (TargetTriple.isOSBinFormatMachO())
 995     return "\1section$end$__DATA$__" + Section;
 996   return "__stop___" + Section;
 997 }
 998
 999 char ModuleSanitizerCoverageLegacyPass::ID = 0;
1000 INITIALIZE_PASS_BEGIN(ModuleSanitizerCoverageLegacyPass, "sancov",
1001                       "Pass for instrumenting coverage on functions", false,
1002                       false)
1003 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
1004 INITIALIZE_PASS_DEPENDENCY(PostDominatorTreeWrapperPass)
1005 INITIALIZE_PASS_END(ModuleSanitizerCoverageLegacyPass, "sancov",
1006                     "Pass for instrumenting coverage on functions", false,
1007                     false)
1008 ModulePass *llvm::createModuleSanitizerCoverageLegacyPassPass(
1009     const SanitizerCoverageOptions &Options,
1010     const std::vector<std::string> &AllowlistFiles,
1011     const std::vector<std::string> &BlocklistFiles) {
1012   return new ModuleSanitizerCoverageLegacyPass(Options, AllowlistFiles,
1013                                                BlocklistFiles);
1014 }