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
44using namespace llvm;
45
46#define DEBUG_TYPE "sancov"
47
48static const char *const SanCovTracePCIndirName =
49    "__sanitizer_cov_trace_pc_indir";
50static const char *const SanCovTracePCName = "__sanitizer_cov_trace_pc";
51static const char *const SanCovTraceCmp1 = "__sanitizer_cov_trace_cmp1";
52static const char *const SanCovTraceCmp2 = "__sanitizer_cov_trace_cmp2";
53static const char *const SanCovTraceCmp4 = "__sanitizer_cov_trace_cmp4";
54static const char *const SanCovTraceCmp8 = "__sanitizer_cov_trace_cmp8";
55static const char *const SanCovTraceConstCmp1 =
56    "__sanitizer_cov_trace_const_cmp1";
57static const char *const SanCovTraceConstCmp2 =
58    "__sanitizer_cov_trace_const_cmp2";
59static const char *const SanCovTraceConstCmp4 =
60    "__sanitizer_cov_trace_const_cmp4";
61static const char *const SanCovTraceConstCmp8 =
62    "__sanitizer_cov_trace_const_cmp8";
63static const char *const SanCovTraceDiv4 = "__sanitizer_cov_trace_div4";
64static const char *const SanCovTraceDiv8 = "__sanitizer_cov_trace_div8";
65static const char *const SanCovTraceGep = "__sanitizer_cov_trace_gep";
66static const char *const SanCovTraceSwitchName = "__sanitizer_cov_trace_switch";
67static const char *const SanCovModuleCtorTracePcGuardName =
68    "sancov.module_ctor_trace_pc_guard";
69static const char *const SanCovModuleCtor8bitCountersName =
70    "sancov.module_ctor_8bit_counters";
71static const char *const SanCovModuleCtorBoolFlagName =
72    "sancov.module_ctor_bool_flag";
73static const uint64_t SanCtorAndDtorPriority = 2;
74
75static const char *const SanCovTracePCGuardName =
76    "__sanitizer_cov_trace_pc_guard";
77static const char *const SanCovTracePCGuardInitName =
78    "__sanitizer_cov_trace_pc_guard_init";
79static const char *const SanCov8bitCountersInitName =
80    "__sanitizer_cov_8bit_counters_init";
81static const char *const SanCovBoolFlagInitName =
82    "__sanitizer_cov_bool_flag_init";
83static const char *const SanCovPCsInitName = "__sanitizer_cov_pcs_init";
84
85static const char *const SanCovGuardsSectionName = "sancov_guards";
86static const char *const SanCovCountersSectionName = "sancov_cntrs";
87static const char *const SanCovBoolFlagSectionName = "sancov_bools";
88static const char *const SanCovPCsSectionName = "sancov_pcs";
89
90static const char *const SanCovLowestStackName = "__sancov_lowest_stack";
91
92static cl::opt<int> ClCoverageLevel(
93    "sanitizer-coverage-level",
94    cl::desc("Sanitizer Coverage. 0: none, 1: entry block, 2: all blocks, "
95             "3: all blocks and critical edges"),
96    cl::Hidden, cl::init(0));
97
98static cl::opt<bool> ClTracePC("sanitizer-coverage-trace-pc",
99                               cl::desc("Experimental pc tracing"), cl::Hidden,
100                               cl::init(false));
101
102static cl::opt<bool> ClTracePCGuard("sanitizer-coverage-trace-pc-guard",
103                                    cl::desc("pc tracing with a guard"),
104                                    cl::Hidden, cl::init(false));
105
106// If true, we create a global variable that contains PCs of all instrumented
107// BBs, put this global into a named section, and pass this section's bounds
108// to __sanitizer_cov_pcs_init.
109// This way the coverage instrumentation does not need to acquire the PCs
110// at run-time. Works with trace-pc-guard, inline-8bit-counters, and
111// inline-bool-flag.
112static cl::opt<bool> ClCreatePCTable("sanitizer-coverage-pc-table",
113                                     cl::desc("create a static PC table"),
114                                     cl::Hidden, cl::init(false));
115
116static cl::opt<bool>
117    ClInline8bitCounters("sanitizer-coverage-inline-8bit-counters",
118                         cl::desc("increments 8-bit counter for every edge"),
119                         cl::Hidden, cl::init(false));
120
121static cl::opt<bool>
122    ClInlineBoolFlag("sanitizer-coverage-inline-bool-flag",
123                     cl::desc("sets a boolean flag for every edge"), cl::Hidden,
124                     cl::init(false));
125
126static cl::opt<bool>
127    ClCMPTracing("sanitizer-coverage-trace-compares",
128                 cl::desc("Tracing of CMP and similar instructions"),
129                 cl::Hidden, cl::init(false));
130
131static cl::opt<bool> ClDIVTracing("sanitizer-coverage-trace-divs",
132                                  cl::desc("Tracing of DIV instructions"),
133                                  cl::Hidden, cl::init(false));
134
135static cl::opt<bool> ClGEPTracing("sanitizer-coverage-trace-geps",
136                                  cl::desc("Tracing of GEP instructions"),
137                                  cl::Hidden, cl::init(false));
138
139static cl::opt<bool>
140    ClPruneBlocks("sanitizer-coverage-prune-blocks",
141                  cl::desc("Reduce the number of instrumented blocks"),
142                  cl::Hidden, cl::init(true));
143
144static cl::opt<bool> ClStackDepth("sanitizer-coverage-stack-depth",
145                                  cl::desc("max stack depth tracing"),
146                                  cl::Hidden, cl::init(false));
147
148namespace {
149
150SanitizerCoverageOptions getOptions(int LegacyCoverageLevel) {
151  SanitizerCoverageOptions Res;
152  switch (LegacyCoverageLevel) {
153  case 0:
154    Res.CoverageType = SanitizerCoverageOptions::SCK_None;
155    break;
156  case 1:
157    Res.CoverageType = SanitizerCoverageOptions::SCK_Function;
158    break;
159  case 2:
160    Res.CoverageType = SanitizerCoverageOptions::SCK_BB;
161    break;
162  case 3:
163    Res.CoverageType = SanitizerCoverageOptions::SCK_Edge;
164    break;
165  case 4:
166    Res.CoverageType = SanitizerCoverageOptions::SCK_Edge;
167    Res.IndirectCalls = true;
168    break;
169  }
170  return Res;
171}
172
173SanitizerCoverageOptions OverrideFromCL(SanitizerCoverageOptions Options) {
174  // Sets CoverageType and IndirectCalls.
175  SanitizerCoverageOptions CLOpts = getOptions(ClCoverageLevel);
176  Options.CoverageType = std::max(Options.CoverageType, CLOpts.CoverageType);
177  Options.IndirectCalls |= CLOpts.IndirectCalls;
178  Options.TraceCmp |= ClCMPTracing;
179  Options.TraceDiv |= ClDIVTracing;
180  Options.TraceGep |= ClGEPTracing;
181  Options.TracePC |= ClTracePC;
182  Options.TracePCGuard |= ClTracePCGuard;
183  Options.Inline8bitCounters |= ClInline8bitCounters;
184  Options.InlineBoolFlag |= ClInlineBoolFlag;
185  Options.PCTable |= ClCreatePCTable;
186  Options.NoPrune |= !ClPruneBlocks;
187  Options.StackDepth |= ClStackDepth;
188  if (!Options.TracePCGuard && !Options.TracePC &&
189      !Options.Inline8bitCounters && !Options.StackDepth &&
190      !Options.InlineBoolFlag)
191    Options.TracePCGuard = true; // TracePCGuard is default.
192  return Options;
193}
194
195using DomTreeCallback = function_ref<const DominatorTree *(Function &F)>;
196using PostDomTreeCallback =
197    function_ref<const PostDominatorTree *(Function &F)>;
198
199class ModuleSanitizerCoverage {
200public:
201  ModuleSanitizerCoverage(
202      const SanitizerCoverageOptions &Options = SanitizerCoverageOptions(),
203      const SpecialCaseList *Allowlist = nullptr,
204      const SpecialCaseList *Blocklist = nullptr)
205      : Options(OverrideFromCL(Options)), Allowlist(Allowlist),
206        Blocklist(Blocklist) {}
207  bool instrumentModule(Module &M, DomTreeCallback DTCallback,
208                        PostDomTreeCallback PDTCallback);
209
210private:
211  void instrumentFunction(Function &F, DomTreeCallback DTCallback,
212                          PostDomTreeCallback PDTCallback);
213  void InjectCoverageForIndirectCalls(Function &F,
214                                      ArrayRef<Instruction *> IndirCalls);
215  void InjectTraceForCmp(Function &F, ArrayRef<Instruction *> CmpTraceTargets);
216  void InjectTraceForDiv(Function &F,
217                         ArrayRef<BinaryOperator *> DivTraceTargets);
218  void InjectTraceForGep(Function &F,
219                         ArrayRef<GetElementPtrInst *> GepTraceTargets);
220  void InjectTraceForSwitch(Function &F,
221                            ArrayRef<Instruction *> SwitchTraceTargets);
222  bool InjectCoverage(Function &F, ArrayRef<BasicBlock *> AllBlocks,
223                      bool IsLeafFunc = true);
224  GlobalVariable *CreateFunctionLocalArrayInSection(size_t NumElements,
225                                                    Function &F, Type *Ty,
226                                                    const char *Section);
227  GlobalVariable *CreatePCArray(Function &F, ArrayRef<BasicBlock *> AllBlocks);
228  void CreateFunctionLocalArrays(Function &F, ArrayRef<BasicBlock *> AllBlocks);
229  void InjectCoverageAtBlock(Function &F, BasicBlock &BB, size_t Idx,
230                             bool IsLeafFunc = true);
231  Function *CreateInitCallsForSections(Module &M, const char *CtorName,
232                                       const char *InitFunctionName, Type *Ty,
233                                       const char *Section);
234  std::pair<Value *, Value *> CreateSecStartEnd(Module &M, const char *Section,
235                                                Type *Ty);
236
237  void SetNoSanitizeMetadata(Instruction *I) {
238    I->setMetadata(I->getModule()->getMDKindID("nosanitize"),
239                   MDNode::get(*C, None));
240  }
241
242  std::string getSectionName(const std::string &Section) const;
243  std::string getSectionStart(const std::string &Section) const;
244  std::string getSectionEnd(const std::string &Section) const;
245  FunctionCallee SanCovTracePCIndir;
246  FunctionCallee SanCovTracePC, SanCovTracePCGuard;
247  FunctionCallee SanCovTraceCmpFunction[4];
248  FunctionCallee SanCovTraceConstCmpFunction[4];
249  FunctionCallee SanCovTraceDivFunction[2];
250  FunctionCallee SanCovTraceGepFunction;
251  FunctionCallee SanCovTraceSwitchFunction;
252  GlobalVariable *SanCovLowestStack;
253  Type *IntptrTy, *IntptrPtrTy, *Int64Ty, *Int64PtrTy, *Int32Ty, *Int32PtrTy,
254      *Int16Ty, *Int8Ty, *Int8PtrTy, *Int1Ty, *Int1PtrTy;
255  Module *CurModule;
256  std::string CurModuleUniqueId;
257  Triple TargetTriple;
258  LLVMContext *C;
259  const DataLayout *DL;
260
261  GlobalVariable *FunctionGuardArray;  // for trace-pc-guard.
262  GlobalVariable *Function8bitCounterArray;  // for inline-8bit-counters.
263  GlobalVariable *FunctionBoolArray;         // for inline-bool-flag.
264  GlobalVariable *FunctionPCsArray;  // for pc-table.
265  SmallVector<GlobalValue *, 20> GlobalsToAppendToUsed;
266  SmallVector<GlobalValue *, 20> GlobalsToAppendToCompilerUsed;
267
268  SanitizerCoverageOptions Options;
269
270  const SpecialCaseList *Allowlist;
271  const SpecialCaseList *Blocklist;
272};
273
274class ModuleSanitizerCoverageLegacyPass : public ModulePass {
275public:
276  ModuleSanitizerCoverageLegacyPass(
277      const SanitizerCoverageOptions &Options = SanitizerCoverageOptions(),
278      const std::vector<std::string> &AllowlistFiles =
279          std::vector<std::string>(),
280      const std::vector<std::string> &BlocklistFiles =
281          std::vector<std::string>())
282      : ModulePass(ID), Options(Options) {
283    if (AllowlistFiles.size() > 0)
284      Allowlist = SpecialCaseList::createOrDie(AllowlistFiles,
285                                               *vfs::getRealFileSystem());
286    if (BlocklistFiles.size() > 0)
287      Blocklist = SpecialCaseList::createOrDie(BlocklistFiles,
288                                               *vfs::getRealFileSystem());
289    initializeModuleSanitizerCoverageLegacyPassPass(
290        *PassRegistry::getPassRegistry());
291  }
292  bool runOnModule(Module &M) override {
293    ModuleSanitizerCoverage ModuleSancov(Options, Allowlist.get(),
294                                         Blocklist.get());
295    auto DTCallback = [this](Function &F) -> const DominatorTree * {
296      return &this->getAnalysis<DominatorTreeWrapperPass>(F).getDomTree();
297    };
298    auto PDTCallback = [this](Function &F) -> const PostDominatorTree * {
299      return &this->getAnalysis<PostDominatorTreeWrapperPass>(F)
300                  .getPostDomTree();
301    };
302    return ModuleSancov.instrumentModule(M, DTCallback, PDTCallback);
303  }
304
305  static char ID; // Pass identification, replacement for typeid
306  StringRef getPassName() const override { return "ModuleSanitizerCoverage"; }
307
308  void getAnalysisUsage(AnalysisUsage &AU) const override {
309    AU.addRequired<DominatorTreeWrapperPass>();
310    AU.addRequired<PostDominatorTreeWrapperPass>();
311  }
312
313private:
314  SanitizerCoverageOptions Options;
315
316  std::unique_ptr<SpecialCaseList> Allowlist;
317  std::unique_ptr<SpecialCaseList> Blocklist;
318};
319
320} // namespace
321
322PreservedAnalyses ModuleSanitizerCoveragePass::run(Module &M,
323                                                   ModuleAnalysisManager &MAM) {
324  ModuleSanitizerCoverage ModuleSancov(Options, Allowlist.get(),
325                                       Blocklist.get());
326  auto &FAM = MAM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
327  auto DTCallback = [&FAM](Function &F) -> const DominatorTree * {
328    return &FAM.getResult<DominatorTreeAnalysis>(F);
329  };
330  auto PDTCallback = [&FAM](Function &F) -> const PostDominatorTree * {
331    return &FAM.getResult<PostDominatorTreeAnalysis>(F);
332  };
333  if (ModuleSancov.instrumentModule(M, DTCallback, PDTCallback))
334    return PreservedAnalyses::none();
335  return PreservedAnalyses::all();
336}
337
338std::pair<Value *, Value *>
339ModuleSanitizerCoverage::CreateSecStartEnd(Module &M, const char *Section,
340                                           Type *Ty) {
341  GlobalVariable *SecStart =
342      new GlobalVariable(M, Ty, false, GlobalVariable::ExternalLinkage, nullptr,
343                         getSectionStart(Section));
344  SecStart->setVisibility(GlobalValue::HiddenVisibility);
345  GlobalVariable *SecEnd =
346      new GlobalVariable(M, Ty, false, GlobalVariable::ExternalLinkage,
347                         nullptr, getSectionEnd(Section));
348  SecEnd->setVisibility(GlobalValue::HiddenVisibility);
349  IRBuilder<> IRB(M.getContext());
350  Value *SecEndPtr = IRB.CreatePointerCast(SecEnd, Ty);
351  if (!TargetTriple.isOSBinFormatCOFF())
352    return std::make_pair(IRB.CreatePointerCast(SecStart, Ty), SecEndPtr);
353
354  // Account for the fact that on windows-msvc __start_* symbols actually
355  // point to a uint64_t before the start of the array.
356  auto SecStartI8Ptr = IRB.CreatePointerCast(SecStart, Int8PtrTy);
357  auto GEP = IRB.CreateGEP(Int8Ty, SecStartI8Ptr,
358                           ConstantInt::get(IntptrTy, sizeof(uint64_t)));
359  return std::make_pair(IRB.CreatePointerCast(GEP, Ty), SecEndPtr);
360}
361
362Function *ModuleSanitizerCoverage::CreateInitCallsForSections(
363    Module &M, const char *CtorName, const char *InitFunctionName, Type *Ty,
364    const char *Section) {
365  auto SecStartEnd = CreateSecStartEnd(M, Section, Ty);
366  auto SecStart = SecStartEnd.first;
367  auto SecEnd = SecStartEnd.second;
368  Function *CtorFunc;
369  std::tie(CtorFunc, std::ignore) = createSanitizerCtorAndInitFunctions(
370      M, CtorName, InitFunctionName, {Ty, Ty}, {SecStart, SecEnd});
371  assert(CtorFunc->getName() == CtorName);
372
373  if (TargetTriple.supportsCOMDAT()) {
374    // Use comdat to dedup CtorFunc.
375    CtorFunc->setComdat(M.getOrInsertComdat(CtorName));
376    appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority, CtorFunc);
377  } else {
378    appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority);
379  }
380
381  if (TargetTriple.isOSBinFormatCOFF()) {
382    // In COFF files, if the contructors are set as COMDAT (they are because
383    // COFF supports COMDAT) and the linker flag /OPT:REF (strip unreferenced
384    // functions and data) is used, the constructors get stripped. To prevent
385    // this, give the constructors weak ODR linkage and ensure the linker knows
386    // to include the sancov constructor. This way the linker can deduplicate
387    // the constructors but always leave one copy.
388    CtorFunc->setLinkage(GlobalValue::WeakODRLinkage);
389    appendToUsed(M, CtorFunc);
390  }
391  return CtorFunc;
392}
393
394bool ModuleSanitizerCoverage::instrumentModule(
395    Module &M, DomTreeCallback DTCallback, PostDomTreeCallback PDTCallback) {
396  if (Options.CoverageType == SanitizerCoverageOptions::SCK_None)
397    return false;
398  if (Allowlist &&
399      !Allowlist->inSection("coverage", "src", M.getSourceFileName()))
400    return false;
401  if (Blocklist &&
402      Blocklist->inSection("coverage", "src", M.getSourceFileName()))
403    return false;
404  C = &(M.getContext());
405  DL = &M.getDataLayout();
406  CurModule = &M;
407  CurModuleUniqueId = getUniqueModuleId(CurModule);
408  TargetTriple = Triple(M.getTargetTriple());
409  FunctionGuardArray = nullptr;
410  Function8bitCounterArray = nullptr;
411  FunctionBoolArray = nullptr;
412  FunctionPCsArray = nullptr;
413  IntptrTy = Type::getIntNTy(*C, DL->getPointerSizeInBits());
414  IntptrPtrTy = PointerType::getUnqual(IntptrTy);
415  Type *VoidTy = Type::getVoidTy(*C);
416  IRBuilder<> IRB(*C);
417  Int64PtrTy = PointerType::getUnqual(IRB.getInt64Ty());
418  Int32PtrTy = PointerType::getUnqual(IRB.getInt32Ty());
419  Int8PtrTy = PointerType::getUnqual(IRB.getInt8Ty());
420  Int1PtrTy = PointerType::getUnqual(IRB.getInt1Ty());
421  Int64Ty = IRB.getInt64Ty();
422  Int32Ty = IRB.getInt32Ty();
423  Int16Ty = IRB.getInt16Ty();
424  Int8Ty = IRB.getInt8Ty();
425  Int1Ty = IRB.getInt1Ty();
426
427  SanCovTracePCIndir =
428      M.getOrInsertFunction(SanCovTracePCIndirName, VoidTy, IntptrTy);
429  // Make sure smaller parameters are zero-extended to i64 as required by the
430  // x86_64 ABI.
431  AttributeList SanCovTraceCmpZeroExtAL;
432  if (TargetTriple.getArch() == Triple::x86_64) {
433    SanCovTraceCmpZeroExtAL =
434        SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 0, Attribute::ZExt);
435    SanCovTraceCmpZeroExtAL =
436        SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 1, Attribute::ZExt);
437  }
438
439  SanCovTraceCmpFunction[0] =
440      M.getOrInsertFunction(SanCovTraceCmp1, SanCovTraceCmpZeroExtAL, VoidTy,
441                            IRB.getInt8Ty(), IRB.getInt8Ty());
442  SanCovTraceCmpFunction[1] =
443      M.getOrInsertFunction(SanCovTraceCmp2, SanCovTraceCmpZeroExtAL, VoidTy,
444                            IRB.getInt16Ty(), IRB.getInt16Ty());
445  SanCovTraceCmpFunction[2] =
446      M.getOrInsertFunction(SanCovTraceCmp4, SanCovTraceCmpZeroExtAL, VoidTy,
447                            IRB.getInt32Ty(), IRB.getInt32Ty());
448  SanCovTraceCmpFunction[3] =
449      M.getOrInsertFunction(SanCovTraceCmp8, VoidTy, Int64Ty, Int64Ty);
450
451  SanCovTraceConstCmpFunction[0] = M.getOrInsertFunction(
452      SanCovTraceConstCmp1, SanCovTraceCmpZeroExtAL, VoidTy, Int8Ty, Int8Ty);
453  SanCovTraceConstCmpFunction[1] = M.getOrInsertFunction(
454      SanCovTraceConstCmp2, SanCovTraceCmpZeroExtAL, VoidTy, Int16Ty, Int16Ty);
455  SanCovTraceConstCmpFunction[2] = M.getOrInsertFunction(
456      SanCovTraceConstCmp4, SanCovTraceCmpZeroExtAL, VoidTy, Int32Ty, Int32Ty);
457  SanCovTraceConstCmpFunction[3] =
458      M.getOrInsertFunction(SanCovTraceConstCmp8, VoidTy, Int64Ty, Int64Ty);
459
460  {
461    AttributeList AL;
462    if (TargetTriple.getArch() == Triple::x86_64)
463      AL = AL.addParamAttribute(*C, 0, Attribute::ZExt);
464    SanCovTraceDivFunction[0] =
465        M.getOrInsertFunction(SanCovTraceDiv4, AL, VoidTy, IRB.getInt32Ty());
466  }
467  SanCovTraceDivFunction[1] =
468      M.getOrInsertFunction(SanCovTraceDiv8, VoidTy, Int64Ty);
469  SanCovTraceGepFunction =
470      M.getOrInsertFunction(SanCovTraceGep, VoidTy, IntptrTy);
471  SanCovTraceSwitchFunction =
472      M.getOrInsertFunction(SanCovTraceSwitchName, VoidTy, Int64Ty, Int64PtrTy);
473
474  Constant *SanCovLowestStackConstant =
475      M.getOrInsertGlobal(SanCovLowestStackName, IntptrTy);
476  SanCovLowestStack = dyn_cast<GlobalVariable>(SanCovLowestStackConstant);
477  if (!SanCovLowestStack) {
478    C->emitError(StringRef("'") + SanCovLowestStackName +
479                 "' should not be declared by the user");
480    return true;
481  }
482  SanCovLowestStack->setThreadLocalMode(
483      GlobalValue::ThreadLocalMode::InitialExecTLSModel);
484  if (Options.StackDepth && !SanCovLowestStack->isDeclaration())
485    SanCovLowestStack->setInitializer(Constant::getAllOnesValue(IntptrTy));
486
487  SanCovTracePC = M.getOrInsertFunction(SanCovTracePCName, VoidTy);
488  SanCovTracePCGuard =
489      M.getOrInsertFunction(SanCovTracePCGuardName, VoidTy, Int32PtrTy);
490
491  for (auto &F : M)
492    instrumentFunction(F, DTCallback, PDTCallback);
493
494  Function *Ctor = nullptr;
495
496  if (FunctionGuardArray)
497    Ctor = CreateInitCallsForSections(M, SanCovModuleCtorTracePcGuardName,
498                                      SanCovTracePCGuardInitName, Int32PtrTy,
499                                      SanCovGuardsSectionName);
500  if (Function8bitCounterArray)
501    Ctor = CreateInitCallsForSections(M, SanCovModuleCtor8bitCountersName,
502                                      SanCov8bitCountersInitName, Int8PtrTy,
503                                      SanCovCountersSectionName);
504  if (FunctionBoolArray) {
505    Ctor = CreateInitCallsForSections(M, SanCovModuleCtorBoolFlagName,
506                                      SanCovBoolFlagInitName, Int1PtrTy,
507                                      SanCovBoolFlagSectionName);
508  }
509  if (Ctor && Options.PCTable) {
510    auto SecStartEnd = CreateSecStartEnd(M, SanCovPCsSectionName, IntptrPtrTy);
511    FunctionCallee InitFunction = declareSanitizerInitFunction(
512        M, SanCovPCsInitName, {IntptrPtrTy, IntptrPtrTy});
513    IRBuilder<> IRBCtor(Ctor->getEntryBlock().getTerminator());
514    IRBCtor.CreateCall(InitFunction, {SecStartEnd.first, SecStartEnd.second});
515  }
516  // We don't reference these arrays directly in any of our runtime functions,
517  // so we need to prevent them from being dead stripped.
518  if (TargetTriple.isOSBinFormatMachO())
519    appendToUsed(M, GlobalsToAppendToUsed);
520  appendToCompilerUsed(M, GlobalsToAppendToCompilerUsed);
521  return true;
522}
523
524// True if block has successors and it dominates all of them.
525static bool isFullDominator(const BasicBlock *BB, const DominatorTree *DT) {
526  if (succ_begin(BB) == succ_end(BB))
527    return false;
528
529  for (const BasicBlock *SUCC : make_range(succ_begin(BB), succ_end(BB))) {
530    if (!DT->dominates(BB, SUCC))
531      return false;
532  }
533
534  return true;
535}
536
537// True if block has predecessors and it postdominates all of them.
538static bool isFullPostDominator(const BasicBlock *BB,
539                                const PostDominatorTree *PDT) {
540  if (pred_begin(BB) == pred_end(BB))
541    return false;
542
543  for (const BasicBlock *PRED : make_range(pred_begin(BB), pred_end(BB))) {
544    if (!PDT->dominates(BB, PRED))
545      return false;
546  }
547
548  return true;
549}
550
551static bool shouldInstrumentBlock(const Function &F, const BasicBlock *BB,
552                                  const DominatorTree *DT,
553                                  const PostDominatorTree *PDT,
554                                  const SanitizerCoverageOptions &Options) {
555  // Don't insert coverage for blocks containing nothing but unreachable: we
556  // will never call __sanitizer_cov() for them, so counting them in
557  // NumberOfInstrumentedBlocks() might complicate calculation of code coverage
558  // percentage. Also, unreachable instructions frequently have no debug
559  // locations.
560  if (isa<UnreachableInst>(BB->getFirstNonPHIOrDbgOrLifetime()))
561    return false;
562
563  // Don't insert coverage into blocks without a valid insertion point
564  // (catchswitch blocks).
565  if (BB->getFirstInsertionPt() == BB->end())
566    return false;
567
568  if (Options.NoPrune || &F.getEntryBlock() == BB)
569    return true;
570
571  if (Options.CoverageType == SanitizerCoverageOptions::SCK_Function &&
572      &F.getEntryBlock() != BB)
573    return false;
574
575  // Do not instrument full dominators, or full post-dominators with multiple
576  // predecessors.
577  return !isFullDominator(BB, DT)
578    && !(isFullPostDominator(BB, PDT) && !BB->getSinglePredecessor());
579}
580
581
582// Returns true iff From->To is a backedge.
583// A twist here is that we treat From->To as a backedge if
584//   * To dominates From or
585//   * To->UniqueSuccessor dominates From
586static bool IsBackEdge(BasicBlock *From, BasicBlock *To,
587                       const DominatorTree *DT) {
588  if (DT->dominates(To, From))
589    return true;
590  if (auto Next = To->getUniqueSuccessor())
591    if (DT->dominates(Next, From))
592      return true;
593  return false;
594}
595
596// Prunes uninteresting Cmp instrumentation:
597//   * CMP instructions that feed into loop backedge branch.
598//
599// Note that Cmp pruning is controlled by the same flag as the
600// BB pruning.
601static bool IsInterestingCmp(ICmpInst *CMP, const DominatorTree *DT,
602                             const SanitizerCoverageOptions &Options) {
603  if (!Options.NoPrune)
604    if (CMP->hasOneUse())
605      if (auto BR = dyn_cast<BranchInst>(CMP->user_back()))
606        for (BasicBlock *B : BR->successors())
607          if (IsBackEdge(BR->getParent(), B, DT))
608            return false;
609  return true;
610}
611
612void ModuleSanitizerCoverage::instrumentFunction(
613    Function &F, DomTreeCallback DTCallback, PostDomTreeCallback PDTCallback) {
614  if (F.empty())
615    return;
616  if (F.getName().find(".module_ctor") != std::string::npos)
617    return; // Should not instrument sanitizer init functions.
618  if (F.getName().startswith("__sanitizer_"))
619    return; // Don't instrument __sanitizer_* callbacks.
620  // Don't touch available_externally functions, their actual body is elewhere.
621  if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage)
622    return;
623  // Don't instrument MSVC CRT configuration helpers. They may run before normal
624  // initialization.
625  if (F.getName() == "__local_stdio_printf_options" ||
626      F.getName() == "__local_stdio_scanf_options")
627    return;
628  if (isa<UnreachableInst>(F.getEntryBlock().getTerminator()))
629    return;
630  // Don't instrument functions using SEH for now. Splitting basic blocks like
631  // we do for coverage breaks WinEHPrepare.
632  // FIXME: Remove this when SEH no longer uses landingpad pattern matching.
633  if (F.hasPersonalityFn() &&
634      isAsynchronousEHPersonality(classifyEHPersonality(F.getPersonalityFn())))
635    return;
636  if (Allowlist && !Allowlist->inSection("coverage", "fun", F.getName()))
637    return;
638  if (Blocklist && Blocklist->inSection("coverage", "fun", F.getName()))
639    return;
640  if (Options.CoverageType >= SanitizerCoverageOptions::SCK_Edge)
641    SplitAllCriticalEdges(F, CriticalEdgeSplittingOptions().setIgnoreUnreachableDests());
642  SmallVector<Instruction *, 8> IndirCalls;
643  SmallVector<BasicBlock *, 16> BlocksToInstrument;
644  SmallVector<Instruction *, 8> CmpTraceTargets;
645  SmallVector<Instruction *, 8> SwitchTraceTargets;
646  SmallVector<BinaryOperator *, 8> DivTraceTargets;
647  SmallVector<GetElementPtrInst *, 8> GepTraceTargets;
648
649  const DominatorTree *DT = DTCallback(F);
650  const PostDominatorTree *PDT = PDTCallback(F);
651  bool IsLeafFunc = true;
652
653  for (auto &BB : F) {
654    if (shouldInstrumentBlock(F, &BB, DT, PDT, Options))
655      BlocksToInstrument.push_back(&BB);
656    for (auto &Inst : BB) {
657      if (Options.IndirectCalls) {
658        CallBase *CB = dyn_cast<CallBase>(&Inst);
659        if (CB && !CB->getCalledFunction())
660          IndirCalls.push_back(&Inst);
661      }
662      if (Options.TraceCmp) {
663        if (ICmpInst *CMP = dyn_cast<ICmpInst>(&Inst))
664          if (IsInterestingCmp(CMP, DT, Options))
665            CmpTraceTargets.push_back(&Inst);
666        if (isa<SwitchInst>(&Inst))
667          SwitchTraceTargets.push_back(&Inst);
668      }
669      if (Options.TraceDiv)
670        if (BinaryOperator *BO = dyn_cast<BinaryOperator>(&Inst))
671          if (BO->getOpcode() == Instruction::SDiv ||
672              BO->getOpcode() == Instruction::UDiv)
673            DivTraceTargets.push_back(BO);
674      if (Options.TraceGep)
675        if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(&Inst))
676          GepTraceTargets.push_back(GEP);
677      if (Options.StackDepth)
678        if (isa<InvokeInst>(Inst) ||
679            (isa<CallInst>(Inst) && !isa<IntrinsicInst>(Inst)))
680          IsLeafFunc = false;
681    }
682  }
683
684  InjectCoverage(F, BlocksToInstrument, IsLeafFunc);
685  InjectCoverageForIndirectCalls(F, IndirCalls);
686  InjectTraceForCmp(F, CmpTraceTargets);
687  InjectTraceForSwitch(F, SwitchTraceTargets);
688  InjectTraceForDiv(F, DivTraceTargets);
689  InjectTraceForGep(F, GepTraceTargets);
690}
691
692GlobalVariable *ModuleSanitizerCoverage::CreateFunctionLocalArrayInSection(
693    size_t NumElements, Function &F, Type *Ty, const char *Section) {
694  ArrayType *ArrayTy = ArrayType::get(Ty, NumElements);
695  auto Array = new GlobalVariable(
696      *CurModule, ArrayTy, false, GlobalVariable::PrivateLinkage,
697      Constant::getNullValue(ArrayTy), "__sancov_gen_");
698
699  if (TargetTriple.supportsCOMDAT() && !F.isInterposable())
700    if (auto Comdat =
701            GetOrCreateFunctionComdat(F, TargetTriple, CurModuleUniqueId))
702      Array->setComdat(Comdat);
703  Array->setSection(getSectionName(Section));
704  Array->setAlignment(Align(DL->getTypeStoreSize(Ty).getFixedSize()));
705  GlobalsToAppendToUsed.push_back(Array);
706  GlobalsToAppendToCompilerUsed.push_back(Array);
707  MDNode *MD = MDNode::get(F.getContext(), ValueAsMetadata::get(&F));
708  Array->addMetadata(LLVMContext::MD_associated, *MD);
709
710  return Array;
711}
712
713GlobalVariable *
714ModuleSanitizerCoverage::CreatePCArray(Function &F,
715                                       ArrayRef<BasicBlock *> AllBlocks) {
716  size_t N = AllBlocks.size();
717  assert(N);
718  SmallVector<Constant *, 32> PCs;
719  IRBuilder<> IRB(&*F.getEntryBlock().getFirstInsertionPt());
720  for (size_t i = 0; i < N; i++) {
721    if (&F.getEntryBlock() == AllBlocks[i]) {
722      PCs.push_back((Constant *)IRB.CreatePointerCast(&F, IntptrPtrTy));
723      PCs.push_back((Constant *)IRB.CreateIntToPtr(
724          ConstantInt::get(IntptrTy, 1), IntptrPtrTy));
725    } else {
726      PCs.push_back((Constant *)IRB.CreatePointerCast(
727          BlockAddress::get(AllBlocks[i]), IntptrPtrTy));
728      PCs.push_back((Constant *)IRB.CreateIntToPtr(
729          ConstantInt::get(IntptrTy, 0), IntptrPtrTy));
730    }
731  }
732  auto *PCArray = CreateFunctionLocalArrayInSection(N * 2, F, IntptrPtrTy,
733                                                    SanCovPCsSectionName);
734  PCArray->setInitializer(
735      ConstantArray::get(ArrayType::get(IntptrPtrTy, N * 2), PCs));
736  PCArray->setConstant(true);
737
738  return PCArray;
739}
740
741void ModuleSanitizerCoverage::CreateFunctionLocalArrays(
742    Function &F, ArrayRef<BasicBlock *> AllBlocks) {
743  if (Options.TracePCGuard)
744    FunctionGuardArray = CreateFunctionLocalArrayInSection(
745        AllBlocks.size(), F, Int32Ty, SanCovGuardsSectionName);
746
747  if (Options.Inline8bitCounters)
748    Function8bitCounterArray = CreateFunctionLocalArrayInSection(
749        AllBlocks.size(), F, Int8Ty, SanCovCountersSectionName);
750  if (Options.InlineBoolFlag)
751    FunctionBoolArray = CreateFunctionLocalArrayInSection(
752        AllBlocks.size(), F, Int1Ty, SanCovBoolFlagSectionName);
753
754  if (Options.PCTable)
755    FunctionPCsArray = CreatePCArray(F, AllBlocks);
756}
757
758bool ModuleSanitizerCoverage::InjectCoverage(Function &F,
759                                             ArrayRef<BasicBlock *> AllBlocks,
760                                             bool IsLeafFunc) {
761  if (AllBlocks.empty()) return false;
762  CreateFunctionLocalArrays(F, AllBlocks);
763  for (size_t i = 0, N = AllBlocks.size(); i < N; i++)
764    InjectCoverageAtBlock(F, *AllBlocks[i], i, IsLeafFunc);
765  return true;
766}
767
768// On every indirect call we call a run-time function
769// __sanitizer_cov_indir_call* with two parameters:
770//   - callee address,
771//   - global cache array that contains CacheSize pointers (zero-initialized).
772//     The cache is used to speed up recording the caller-callee pairs.
773// The address of the caller is passed implicitly via caller PC.
774// CacheSize is encoded in the name of the run-time function.
775void ModuleSanitizerCoverage::InjectCoverageForIndirectCalls(
776    Function &F, ArrayRef<Instruction *> IndirCalls) {
777  if (IndirCalls.empty())
778    return;
779  assert(Options.TracePC || Options.TracePCGuard ||
780         Options.Inline8bitCounters || Options.InlineBoolFlag);
781  for (auto I : IndirCalls) {
782    IRBuilder<> IRB(I);
783    CallBase &CB = cast<CallBase>(*I);
784    Value *Callee = CB.getCalledOperand();
785    if (isa<InlineAsm>(Callee))
786      continue;
787    IRB.CreateCall(SanCovTracePCIndir, IRB.CreatePointerCast(Callee, IntptrTy));
788  }
789}
790
791// For every switch statement we insert a call:
792// __sanitizer_cov_trace_switch(CondValue,
793//      {NumCases, ValueSizeInBits, Case0Value, Case1Value, Case2Value, ... })
794
795void ModuleSanitizerCoverage::InjectTraceForSwitch(
796    Function &, ArrayRef<Instruction *> SwitchTraceTargets) {
797  for (auto I : SwitchTraceTargets) {
798    if (SwitchInst *SI = dyn_cast<SwitchInst>(I)) {
799      IRBuilder<> IRB(I);
800      SmallVector<Constant *, 16> Initializers;
801      Value *Cond = SI->getCondition();
802      if (Cond->getType()->getScalarSizeInBits() >
803          Int64Ty->getScalarSizeInBits())
804        continue;
805      Initializers.push_back(ConstantInt::get(Int64Ty, SI->getNumCases()));
806      Initializers.push_back(
807          ConstantInt::get(Int64Ty, Cond->getType()->getScalarSizeInBits()));
808      if (Cond->getType()->getScalarSizeInBits() <
809          Int64Ty->getScalarSizeInBits())
810        Cond = IRB.CreateIntCast(Cond, Int64Ty, false);
811      for (auto It : SI->cases()) {
812        Constant *C = It.getCaseValue();
813        if (C->getType()->getScalarSizeInBits() <
814            Int64Ty->getScalarSizeInBits())
815          C = ConstantExpr::getCast(CastInst::ZExt, It.getCaseValue(), Int64Ty);
816        Initializers.push_back(C);
817      }
818      llvm::sort(Initializers.begin() + 2, Initializers.end(),
819                 [](const Constant *A, const Constant *B) {
820                   return cast<ConstantInt>(A)->getLimitedValue() <
821                          cast<ConstantInt>(B)->getLimitedValue();
822                 });
823      ArrayType *ArrayOfInt64Ty = ArrayType::get(Int64Ty, Initializers.size());
824      GlobalVariable *GV = new GlobalVariable(
825          *CurModule, ArrayOfInt64Ty, false, GlobalVariable::InternalLinkage,
826          ConstantArray::get(ArrayOfInt64Ty, Initializers),
827          "__sancov_gen_cov_switch_values");
828      IRB.CreateCall(SanCovTraceSwitchFunction,
829                     {Cond, IRB.CreatePointerCast(GV, Int64PtrTy)});
830    }
831  }
832}
833
834void ModuleSanitizerCoverage::InjectTraceForDiv(
835    Function &, ArrayRef<BinaryOperator *> DivTraceTargets) {
836  for (auto BO : DivTraceTargets) {
837    IRBuilder<> IRB(BO);
838    Value *A1 = BO->getOperand(1);
839    if (isa<ConstantInt>(A1)) continue;
840    if (!A1->getType()->isIntegerTy())
841      continue;
842    uint64_t TypeSize = DL->getTypeStoreSizeInBits(A1->getType());
843    int CallbackIdx = TypeSize == 32 ? 0 :
844        TypeSize == 64 ? 1 : -1;
845    if (CallbackIdx < 0) continue;
846    auto Ty = Type::getIntNTy(*C, TypeSize);
847    IRB.CreateCall(SanCovTraceDivFunction[CallbackIdx],
848                   {IRB.CreateIntCast(A1, Ty, true)});
849  }
850}
851
852void ModuleSanitizerCoverage::InjectTraceForGep(
853    Function &, ArrayRef<GetElementPtrInst *> GepTraceTargets) {
854  for (auto GEP : GepTraceTargets) {
855    IRBuilder<> IRB(GEP);
856    for (auto I = GEP->idx_begin(); I != GEP->idx_end(); ++I)
857      if (!isa<ConstantInt>(*I) && (*I)->getType()->isIntegerTy())
858        IRB.CreateCall(SanCovTraceGepFunction,
859                       {IRB.CreateIntCast(*I, IntptrTy, true)});
860  }
861}
862
863void ModuleSanitizerCoverage::InjectTraceForCmp(
864    Function &, ArrayRef<Instruction *> CmpTraceTargets) {
865  for (auto I : CmpTraceTargets) {
866    if (ICmpInst *ICMP = dyn_cast<ICmpInst>(I)) {
867      IRBuilder<> IRB(ICMP);
868      Value *A0 = ICMP->getOperand(0);
869      Value *A1 = ICMP->getOperand(1);
870      if (!A0->getType()->isIntegerTy())
871        continue;
872      uint64_t TypeSize = DL->getTypeStoreSizeInBits(A0->getType());
873      int CallbackIdx = TypeSize == 8 ? 0 :
874                        TypeSize == 16 ? 1 :
875                        TypeSize == 32 ? 2 :
876                        TypeSize == 64 ? 3 : -1;
877      if (CallbackIdx < 0) continue;
878      // __sanitizer_cov_trace_cmp((type_size << 32) | predicate, A0, A1);
879      auto CallbackFunc = SanCovTraceCmpFunction[CallbackIdx];
880      bool FirstIsConst = isa<ConstantInt>(A0);
881      bool SecondIsConst = isa<ConstantInt>(A1);
882      // If both are const, then we don't need such a comparison.
883      if (FirstIsConst && SecondIsConst) continue;
884      // If only one is const, then make it the first callback argument.
885      if (FirstIsConst || SecondIsConst) {
886        CallbackFunc = SanCovTraceConstCmpFunction[CallbackIdx];
887        if (SecondIsConst)
888          std::swap(A0, A1);
889      }
890
891      auto Ty = Type::getIntNTy(*C, TypeSize);
892      IRB.CreateCall(CallbackFunc, {IRB.CreateIntCast(A0, Ty, true),
893              IRB.CreateIntCast(A1, Ty, true)});
894    }
895  }
896}
897
898void ModuleSanitizerCoverage::InjectCoverageAtBlock(Function &F, BasicBlock &BB,
899                                                    size_t Idx,
900                                                    bool IsLeafFunc) {
901  BasicBlock::iterator IP = BB.getFirstInsertionPt();
902  bool IsEntryBB = &BB == &F.getEntryBlock();
903  DebugLoc EntryLoc;
904  if (IsEntryBB) {
905    if (auto SP = F.getSubprogram())
906      EntryLoc = DebugLoc::get(SP->getScopeLine(), 0, SP);
907    // Keep static allocas and llvm.localescape calls in the entry block.  Even
908    // if we aren't splitting the block, it's nice for allocas to be before
909    // calls.
910    IP = PrepareToSplitEntryBlock(BB, IP);
911  } else {
912    EntryLoc = IP->getDebugLoc();
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
969std::string
970ModuleSanitizerCoverage::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
985std::string
986ModuleSanitizerCoverage::getSectionStart(const std::string &Section) const {
987  if (TargetTriple.isOSBinFormatMachO())
988    return "\1section$start$__DATA$__" + Section;
989  return "__start___" + Section;
990}
991
992std::string
993ModuleSanitizerCoverage::getSectionEnd(const std::string &Section) const {
994  if (TargetTriple.isOSBinFormatMachO())
995    return "\1section$end$__DATA$__" + Section;
996  return "__stop___" + Section;
997}
998
999char ModuleSanitizerCoverageLegacyPass::ID = 0;
1000INITIALIZE_PASS_BEGIN(ModuleSanitizerCoverageLegacyPass, "sancov",
1001                      "Pass for instrumenting coverage on functions", false,
1002                      false)
1003INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
1004INITIALIZE_PASS_DEPENDENCY(PostDominatorTreeWrapperPass)
1005INITIALIZE_PASS_END(ModuleSanitizerCoverageLegacyPass, "sancov",
1006                    "Pass for instrumenting coverage on functions", false,
1007                    false)
1008ModulePass *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}
1015