xref: /llvm-project/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp (revision 1067f2177aa69dca0b9ffef57f5017c28cf9aed3) 
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/ADT/Triple.h"
17 #include "llvm/Analysis/EHPersonalities.h"
18 #include "llvm/Analysis/PostDominators.h"
19 #include "llvm/IR/CFG.h"
20 #include "llvm/IR/Constant.h"
21 #include "llvm/IR/DataLayout.h"
22 #include "llvm/IR/DebugInfo.h"
23 #include "llvm/IR/Dominators.h"
24 #include "llvm/IR/Function.h"
25 #include "llvm/IR/GlobalVariable.h"
26 #include "llvm/IR/IRBuilder.h"
27 #include "llvm/IR/InlineAsm.h"
28 #include "llvm/IR/IntrinsicInst.h"
29 #include "llvm/IR/Intrinsics.h"
30 #include "llvm/IR/LLVMContext.h"
31 #include "llvm/IR/MDBuilder.h"
32 #include "llvm/IR/Mangler.h"
33 #include "llvm/IR/Module.h"
34 #include "llvm/IR/Type.h"
35 #include "llvm/InitializePasses.h"
36 #include "llvm/Support/CommandLine.h"
37 #include "llvm/Support/Debug.h"
38 #include "llvm/Support/SpecialCaseList.h"
39 #include "llvm/Support/VirtualFileSystem.h"
40 #include "llvm/Support/raw_ostream.h"
41 #include "llvm/Transforms/Instrumentation.h"
42 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
43 #include "llvm/Transforms/Utils/ModuleUtils.h"
44 
45 using namespace llvm;
46 
47 #define DEBUG_TYPE "sancov"
48 
49 const char SanCovTracePCIndirName[] = "__sanitizer_cov_trace_pc_indir";
50 const char SanCovTracePCName[] = "__sanitizer_cov_trace_pc";
51 const char SanCovTraceCmp1[] = "__sanitizer_cov_trace_cmp1";
52 const char SanCovTraceCmp2[] = "__sanitizer_cov_trace_cmp2";
53 const char SanCovTraceCmp4[] = "__sanitizer_cov_trace_cmp4";
54 const char SanCovTraceCmp8[] = "__sanitizer_cov_trace_cmp8";
55 const char SanCovTraceConstCmp1[] = "__sanitizer_cov_trace_const_cmp1";
56 const char SanCovTraceConstCmp2[] = "__sanitizer_cov_trace_const_cmp2";
57 const char SanCovTraceConstCmp4[] = "__sanitizer_cov_trace_const_cmp4";
58 const char SanCovTraceConstCmp8[] = "__sanitizer_cov_trace_const_cmp8";
59 const char SanCovLoad1[] = "__sanitizer_cov_load1";
60 const char SanCovLoad2[] = "__sanitizer_cov_load2";
61 const char SanCovLoad4[] = "__sanitizer_cov_load4";
62 const char SanCovLoad8[] = "__sanitizer_cov_load8";
63 const char SanCovLoad16[] = "__sanitizer_cov_load16";
64 const char SanCovStore1[] = "__sanitizer_cov_store1";
65 const char SanCovStore2[] = "__sanitizer_cov_store2";
66 const char SanCovStore4[] = "__sanitizer_cov_store4";
67 const char SanCovStore8[] = "__sanitizer_cov_store8";
68 const char SanCovStore16[] = "__sanitizer_cov_store16";
69 const char SanCovTraceDiv4[] = "__sanitizer_cov_trace_div4";
70 const char SanCovTraceDiv8[] = "__sanitizer_cov_trace_div8";
71 const char SanCovTraceGep[] = "__sanitizer_cov_trace_gep";
72 const char SanCovTraceSwitchName[] = "__sanitizer_cov_trace_switch";
73 const char SanCovModuleCtorTracePcGuardName[] =
74     "sancov.module_ctor_trace_pc_guard";
75 const char SanCovModuleCtor8bitCountersName[] =
76     "sancov.module_ctor_8bit_counters";
77 const char SanCovModuleCtorBoolFlagName[] = "sancov.module_ctor_bool_flag";
78 static const uint64_t SanCtorAndDtorPriority = 2;
79 
80 const char SanCovTracePCGuardName[] = "__sanitizer_cov_trace_pc_guard";
81 const char SanCovTracePCGuardInitName[] = "__sanitizer_cov_trace_pc_guard_init";
82 const char SanCov8bitCountersInitName[] = "__sanitizer_cov_8bit_counters_init";
83 const char SanCovBoolFlagInitName[] = "__sanitizer_cov_bool_flag_init";
84 const char SanCovPCsInitName[] = "__sanitizer_cov_pcs_init";
85 
86 const char SanCovGuardsSectionName[] = "sancov_guards";
87 const char SanCovCountersSectionName[] = "sancov_cntrs";
88 const char SanCovBoolFlagSectionName[] = "sancov_bools";
89 const char SanCovPCsSectionName[] = "sancov_pcs";
90 
91 const char SanCovLowestStackName[] = "__sancov_lowest_stack";
92 
93 static cl::opt<int> ClCoverageLevel(
94     "sanitizer-coverage-level",
95     cl::desc("Sanitizer Coverage. 0: none, 1: entry block, 2: all blocks, "
96              "3: all blocks and critical edges"),
97     cl::Hidden, cl::init(0));
98 
99 static cl::opt<bool> ClTracePC("sanitizer-coverage-trace-pc",
100                                cl::desc("Experimental pc tracing"), cl::Hidden,
101                                cl::init(false));
102 
103 static cl::opt<bool> ClTracePCGuard("sanitizer-coverage-trace-pc-guard",
104                                     cl::desc("pc tracing with a guard"),
105                                     cl::Hidden, cl::init(false));
106 
107 // If true, we create a global variable that contains PCs of all instrumented
108 // BBs, put this global into a named section, and pass this section's bounds
109 // to __sanitizer_cov_pcs_init.
110 // This way the coverage instrumentation does not need to acquire the PCs
111 // at run-time. Works with trace-pc-guard, inline-8bit-counters, and
112 // inline-bool-flag.
113 static cl::opt<bool> ClCreatePCTable("sanitizer-coverage-pc-table",
114                                      cl::desc("create a static PC table"),
115                                      cl::Hidden, cl::init(false));
116 
117 static cl::opt<bool>
118     ClInline8bitCounters("sanitizer-coverage-inline-8bit-counters",
119                          cl::desc("increments 8-bit counter for every edge"),
120                          cl::Hidden, cl::init(false));
121 
122 static cl::opt<bool>
123     ClInlineBoolFlag("sanitizer-coverage-inline-bool-flag",
124                      cl::desc("sets a boolean flag for every edge"), cl::Hidden,
125                      cl::init(false));
126 
127 static cl::opt<bool>
128     ClCMPTracing("sanitizer-coverage-trace-compares",
129                  cl::desc("Tracing of CMP and similar instructions"),
130                  cl::Hidden, cl::init(false));
131 
132 static cl::opt<bool> ClDIVTracing("sanitizer-coverage-trace-divs",
133                                   cl::desc("Tracing of DIV instructions"),
134                                   cl::Hidden, cl::init(false));
135 
136 static cl::opt<bool> ClLoadTracing("sanitizer-coverage-trace-loads",
137                                    cl::desc("Tracing of load instructions"),
138                                    cl::Hidden, cl::init(false));
139 
140 static cl::opt<bool> ClStoreTracing("sanitizer-coverage-trace-stores",
141                                     cl::desc("Tracing of store instructions"),
142                                     cl::Hidden, cl::init(false));
143 
144 static cl::opt<bool> ClGEPTracing("sanitizer-coverage-trace-geps",
145                                   cl::desc("Tracing of GEP instructions"),
146                                   cl::Hidden, cl::init(false));
147 
148 static cl::opt<bool>
149     ClPruneBlocks("sanitizer-coverage-prune-blocks",
150                   cl::desc("Reduce the number of instrumented blocks"),
151                   cl::Hidden, cl::init(true));
152 
153 static cl::opt<bool> ClStackDepth("sanitizer-coverage-stack-depth",
154                                   cl::desc("max stack depth tracing"),
155                                   cl::Hidden, cl::init(false));
156 
157 namespace {
158 
159 SanitizerCoverageOptions getOptions(int LegacyCoverageLevel) {
160   SanitizerCoverageOptions Res;
161   switch (LegacyCoverageLevel) {
162   case 0:
163     Res.CoverageType = SanitizerCoverageOptions::SCK_None;
164     break;
165   case 1:
166     Res.CoverageType = SanitizerCoverageOptions::SCK_Function;
167     break;
168   case 2:
169     Res.CoverageType = SanitizerCoverageOptions::SCK_BB;
170     break;
171   case 3:
172     Res.CoverageType = SanitizerCoverageOptions::SCK_Edge;
173     break;
174   case 4:
175     Res.CoverageType = SanitizerCoverageOptions::SCK_Edge;
176     Res.IndirectCalls = true;
177     break;
178   }
179   return Res;
180 }
181 
182 SanitizerCoverageOptions OverrideFromCL(SanitizerCoverageOptions Options) {
183   // Sets CoverageType and IndirectCalls.
184   SanitizerCoverageOptions CLOpts = getOptions(ClCoverageLevel);
185   Options.CoverageType = std::max(Options.CoverageType, CLOpts.CoverageType);
186   Options.IndirectCalls |= CLOpts.IndirectCalls;
187   Options.TraceCmp |= ClCMPTracing;
188   Options.TraceDiv |= ClDIVTracing;
189   Options.TraceGep |= ClGEPTracing;
190   Options.TracePC |= ClTracePC;
191   Options.TracePCGuard |= ClTracePCGuard;
192   Options.Inline8bitCounters |= ClInline8bitCounters;
193   Options.InlineBoolFlag |= ClInlineBoolFlag;
194   Options.PCTable |= ClCreatePCTable;
195   Options.NoPrune |= !ClPruneBlocks;
196   Options.StackDepth |= ClStackDepth;
197   Options.TraceLoads |= ClLoadTracing;
198   Options.TraceStores |= ClStoreTracing;
199   if (!Options.TracePCGuard && !Options.TracePC &&
200       !Options.Inline8bitCounters && !Options.StackDepth &&
201       !Options.InlineBoolFlag && !Options.TraceLoads && !Options.TraceStores)
202     Options.TracePCGuard = true; // TracePCGuard is default.
203   return Options;
204 }
205 
206 using DomTreeCallback = function_ref<const DominatorTree *(Function &F)>;
207 using PostDomTreeCallback =
208     function_ref<const PostDominatorTree *(Function &F)>;
209 
210 class ModuleSanitizerCoverage {
211 public:
212   ModuleSanitizerCoverage(
213       const SanitizerCoverageOptions &Options = SanitizerCoverageOptions(),
214       const SpecialCaseList *Allowlist = nullptr,
215       const SpecialCaseList *Blocklist = nullptr)
216       : Options(OverrideFromCL(Options)), Allowlist(Allowlist),
217         Blocklist(Blocklist) {}
218   bool instrumentModule(Module &M, DomTreeCallback DTCallback,
219                         PostDomTreeCallback PDTCallback);
220 
221 private:
222   void instrumentFunction(Function &F, DomTreeCallback DTCallback,
223                           PostDomTreeCallback PDTCallback);
224   void InjectCoverageForIndirectCalls(Function &F,
225                                       ArrayRef<Instruction *> IndirCalls);
226   void InjectTraceForCmp(Function &F, ArrayRef<Instruction *> CmpTraceTargets);
227   void InjectTraceForDiv(Function &F,
228                          ArrayRef<BinaryOperator *> DivTraceTargets);
229   void InjectTraceForGep(Function &F,
230                          ArrayRef<GetElementPtrInst *> GepTraceTargets);
231   void InjectTraceForLoadsAndStores(Function &F, ArrayRef<LoadInst *> Loads,
232                                     ArrayRef<StoreInst *> Stores);
233   void InjectTraceForSwitch(Function &F,
234                             ArrayRef<Instruction *> SwitchTraceTargets);
235   bool InjectCoverage(Function &F, ArrayRef<BasicBlock *> AllBlocks,
236                       bool IsLeafFunc = true);
237   GlobalVariable *CreateFunctionLocalArrayInSection(size_t NumElements,
238                                                     Function &F, Type *Ty,
239                                                     const char *Section);
240   GlobalVariable *CreatePCArray(Function &F, ArrayRef<BasicBlock *> AllBlocks);
241   void CreateFunctionLocalArrays(Function &F, ArrayRef<BasicBlock *> AllBlocks);
242   void InjectCoverageAtBlock(Function &F, BasicBlock &BB, size_t Idx,
243                              bool IsLeafFunc = true);
244   Function *CreateInitCallsForSections(Module &M, const char *CtorName,
245                                        const char *InitFunctionName, Type *Ty,
246                                        const char *Section);
247   std::pair<Value *, Value *> CreateSecStartEnd(Module &M, const char *Section,
248                                                 Type *Ty);
249 
250   void SetNoSanitizeMetadata(Instruction *I) {
251     I->setMetadata(I->getModule()->getMDKindID("nosanitize"),
252                    MDNode::get(*C, None));
253   }
254 
255   std::string getSectionName(const std::string &Section) const;
256   std::string getSectionStart(const std::string &Section) const;
257   std::string getSectionEnd(const std::string &Section) const;
258   FunctionCallee SanCovTracePCIndir;
259   FunctionCallee SanCovTracePC, SanCovTracePCGuard;
260   std::array<FunctionCallee, 4> SanCovTraceCmpFunction;
261   std::array<FunctionCallee, 4> SanCovTraceConstCmpFunction;
262   std::array<FunctionCallee, 5> SanCovLoadFunction;
263   std::array<FunctionCallee, 5> SanCovStoreFunction;
264   std::array<FunctionCallee, 2> SanCovTraceDivFunction;
265   FunctionCallee SanCovTraceGepFunction;
266   FunctionCallee SanCovTraceSwitchFunction;
267   GlobalVariable *SanCovLowestStack;
268   Type *Int128PtrTy, *IntptrTy, *IntptrPtrTy, *Int64Ty, *Int64PtrTy, *Int32Ty,
269       *Int32PtrTy, *Int16PtrTy, *Int16Ty, *Int8Ty, *Int8PtrTy, *Int1Ty,
270       *Int1PtrTy;
271   Module *CurModule;
272   std::string CurModuleUniqueId;
273   Triple TargetTriple;
274   LLVMContext *C;
275   const DataLayout *DL;
276 
277   GlobalVariable *FunctionGuardArray;  // for trace-pc-guard.
278   GlobalVariable *Function8bitCounterArray;  // for inline-8bit-counters.
279   GlobalVariable *FunctionBoolArray;         // for inline-bool-flag.
280   GlobalVariable *FunctionPCsArray;  // for pc-table.
281   SmallVector<GlobalValue *, 20> GlobalsToAppendToUsed;
282   SmallVector<GlobalValue *, 20> GlobalsToAppendToCompilerUsed;
283 
284   SanitizerCoverageOptions Options;
285 
286   const SpecialCaseList *Allowlist;
287   const SpecialCaseList *Blocklist;
288 };
289 
290 class ModuleSanitizerCoverageLegacyPass : public ModulePass {
291 public:
292   ModuleSanitizerCoverageLegacyPass(
293       const SanitizerCoverageOptions &Options = SanitizerCoverageOptions(),
294       const std::vector<std::string> &AllowlistFiles =
295           std::vector<std::string>(),
296       const std::vector<std::string> &BlocklistFiles =
297           std::vector<std::string>())
298       : ModulePass(ID), Options(Options) {
299     if (AllowlistFiles.size() > 0)
300       Allowlist = SpecialCaseList::createOrDie(AllowlistFiles,
301                                                *vfs::getRealFileSystem());
302     if (BlocklistFiles.size() > 0)
303       Blocklist = SpecialCaseList::createOrDie(BlocklistFiles,
304                                                *vfs::getRealFileSystem());
305     initializeModuleSanitizerCoverageLegacyPassPass(
306         *PassRegistry::getPassRegistry());
307   }
308   bool runOnModule(Module &M) override {
309     ModuleSanitizerCoverage ModuleSancov(Options, Allowlist.get(),
310                                          Blocklist.get());
311     auto DTCallback = [this](Function &F) -> const DominatorTree * {
312       return &this->getAnalysis<DominatorTreeWrapperPass>(F).getDomTree();
313     };
314     auto PDTCallback = [this](Function &F) -> const PostDominatorTree * {
315       return &this->getAnalysis<PostDominatorTreeWrapperPass>(F)
316                   .getPostDomTree();
317     };
318     return ModuleSancov.instrumentModule(M, DTCallback, PDTCallback);
319   }
320 
321   static char ID; // Pass identification, replacement for typeid
322   StringRef getPassName() const override { return "ModuleSanitizerCoverage"; }
323 
324   void getAnalysisUsage(AnalysisUsage &AU) const override {
325     AU.addRequired<DominatorTreeWrapperPass>();
326     AU.addRequired<PostDominatorTreeWrapperPass>();
327   }
328 
329 private:
330   SanitizerCoverageOptions Options;
331 
332   std::unique_ptr<SpecialCaseList> Allowlist;
333   std::unique_ptr<SpecialCaseList> Blocklist;
334 };
335 
336 } // namespace
337 
338 PreservedAnalyses ModuleSanitizerCoveragePass::run(Module &M,
339                                                    ModuleAnalysisManager &MAM) {
340   ModuleSanitizerCoverage ModuleSancov(Options, Allowlist.get(),
341                                        Blocklist.get());
342   auto &FAM = MAM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
343   auto DTCallback = [&FAM](Function &F) -> const DominatorTree * {
344     return &FAM.getResult<DominatorTreeAnalysis>(F);
345   };
346   auto PDTCallback = [&FAM](Function &F) -> const PostDominatorTree * {
347     return &FAM.getResult<PostDominatorTreeAnalysis>(F);
348   };
349   if (ModuleSancov.instrumentModule(M, DTCallback, PDTCallback))
350     return PreservedAnalyses::none();
351   return PreservedAnalyses::all();
352 }
353 
354 std::pair<Value *, Value *>
355 ModuleSanitizerCoverage::CreateSecStartEnd(Module &M, const char *Section,
356                                            Type *Ty) {
357   // Use ExternalWeak so that if all sections are discarded due to section
358   // garbage collection, the linker will not report undefined symbol errors.
359   // Windows defines the start/stop symbols in compiler-rt so no need for
360   // ExternalWeak.
361   GlobalValue::LinkageTypes Linkage = TargetTriple.isOSBinFormatCOFF()
362                                           ? GlobalVariable::ExternalLinkage
363                                           : GlobalVariable::ExternalWeakLinkage;
364   GlobalVariable *SecStart =
365       new GlobalVariable(M, Ty, false, Linkage, nullptr,
366                          getSectionStart(Section));
367   SecStart->setVisibility(GlobalValue::HiddenVisibility);
368   GlobalVariable *SecEnd =
369       new GlobalVariable(M, Ty, false, Linkage, nullptr,
370                          getSectionEnd(Section));
371   SecEnd->setVisibility(GlobalValue::HiddenVisibility);
372   IRBuilder<> IRB(M.getContext());
373   if (!TargetTriple.isOSBinFormatCOFF())
374     return std::make_pair(SecStart, SecEnd);
375 
376   // Account for the fact that on windows-msvc __start_* symbols actually
377   // point to a uint64_t before the start of the array.
378   auto SecStartI8Ptr = IRB.CreatePointerCast(SecStart, Int8PtrTy);
379   auto GEP = IRB.CreateGEP(Int8Ty, SecStartI8Ptr,
380                            ConstantInt::get(IntptrTy, sizeof(uint64_t)));
381   return std::make_pair(IRB.CreatePointerCast(GEP, PointerType::getUnqual(Ty)),
382                         SecEnd);
383 }
384 
385 Function *ModuleSanitizerCoverage::CreateInitCallsForSections(
386     Module &M, const char *CtorName, const char *InitFunctionName, Type *Ty,
387     const char *Section) {
388   auto SecStartEnd = CreateSecStartEnd(M, Section, Ty);
389   auto SecStart = SecStartEnd.first;
390   auto SecEnd = SecStartEnd.second;
391   Function *CtorFunc;
392   Type *PtrTy = PointerType::getUnqual(Ty);
393   std::tie(CtorFunc, std::ignore) = createSanitizerCtorAndInitFunctions(
394       M, CtorName, InitFunctionName, {PtrTy, PtrTy}, {SecStart, SecEnd});
395   assert(CtorFunc->getName() == CtorName);
396 
397   if (TargetTriple.supportsCOMDAT()) {
398     // Use comdat to dedup CtorFunc.
399     CtorFunc->setComdat(M.getOrInsertComdat(CtorName));
400     appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority, CtorFunc);
401   } else {
402     appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority);
403   }
404 
405   if (TargetTriple.isOSBinFormatCOFF()) {
406     // In COFF files, if the contructors are set as COMDAT (they are because
407     // COFF supports COMDAT) and the linker flag /OPT:REF (strip unreferenced
408     // functions and data) is used, the constructors get stripped. To prevent
409     // this, give the constructors weak ODR linkage and ensure the linker knows
410     // to include the sancov constructor. This way the linker can deduplicate
411     // the constructors but always leave one copy.
412     CtorFunc->setLinkage(GlobalValue::WeakODRLinkage);
413   }
414   return CtorFunc;
415 }
416 
417 bool ModuleSanitizerCoverage::instrumentModule(
418     Module &M, DomTreeCallback DTCallback, PostDomTreeCallback PDTCallback) {
419   if (Options.CoverageType == SanitizerCoverageOptions::SCK_None)
420     return false;
421   if (Allowlist &&
422       !Allowlist->inSection("coverage", "src", M.getSourceFileName()))
423     return false;
424   if (Blocklist &&
425       Blocklist->inSection("coverage", "src", M.getSourceFileName()))
426     return false;
427   C = &(M.getContext());
428   DL = &M.getDataLayout();
429   CurModule = &M;
430   CurModuleUniqueId = getUniqueModuleId(CurModule);
431   TargetTriple = Triple(M.getTargetTriple());
432   FunctionGuardArray = nullptr;
433   Function8bitCounterArray = nullptr;
434   FunctionBoolArray = nullptr;
435   FunctionPCsArray = nullptr;
436   IntptrTy = Type::getIntNTy(*C, DL->getPointerSizeInBits());
437   IntptrPtrTy = PointerType::getUnqual(IntptrTy);
438   Type *VoidTy = Type::getVoidTy(*C);
439   IRBuilder<> IRB(*C);
440   Int128PtrTy = PointerType::getUnqual(IRB.getInt128Ty());
441   Int64PtrTy = PointerType::getUnqual(IRB.getInt64Ty());
442   Int16PtrTy = PointerType::getUnqual(IRB.getInt16Ty());
443   Int32PtrTy = PointerType::getUnqual(IRB.getInt32Ty());
444   Int8PtrTy = PointerType::getUnqual(IRB.getInt8Ty());
445   Int1PtrTy = PointerType::getUnqual(IRB.getInt1Ty());
446   Int64Ty = IRB.getInt64Ty();
447   Int32Ty = IRB.getInt32Ty();
448   Int16Ty = IRB.getInt16Ty();
449   Int8Ty = IRB.getInt8Ty();
450   Int1Ty = IRB.getInt1Ty();
451 
452   SanCovTracePCIndir =
453       M.getOrInsertFunction(SanCovTracePCIndirName, VoidTy, IntptrTy);
454   // Make sure smaller parameters are zero-extended to i64 if required by the
455   // target ABI.
456   AttributeList SanCovTraceCmpZeroExtAL;
457   SanCovTraceCmpZeroExtAL =
458       SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 0, Attribute::ZExt);
459   SanCovTraceCmpZeroExtAL =
460       SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 1, Attribute::ZExt);
461 
462   SanCovTraceCmpFunction[0] =
463       M.getOrInsertFunction(SanCovTraceCmp1, SanCovTraceCmpZeroExtAL, VoidTy,
464                             IRB.getInt8Ty(), IRB.getInt8Ty());
465   SanCovTraceCmpFunction[1] =
466       M.getOrInsertFunction(SanCovTraceCmp2, SanCovTraceCmpZeroExtAL, VoidTy,
467                             IRB.getInt16Ty(), IRB.getInt16Ty());
468   SanCovTraceCmpFunction[2] =
469       M.getOrInsertFunction(SanCovTraceCmp4, SanCovTraceCmpZeroExtAL, VoidTy,
470                             IRB.getInt32Ty(), IRB.getInt32Ty());
471   SanCovTraceCmpFunction[3] =
472       M.getOrInsertFunction(SanCovTraceCmp8, VoidTy, Int64Ty, Int64Ty);
473 
474   SanCovTraceConstCmpFunction[0] = M.getOrInsertFunction(
475       SanCovTraceConstCmp1, SanCovTraceCmpZeroExtAL, VoidTy, Int8Ty, Int8Ty);
476   SanCovTraceConstCmpFunction[1] = M.getOrInsertFunction(
477       SanCovTraceConstCmp2, SanCovTraceCmpZeroExtAL, VoidTy, Int16Ty, Int16Ty);
478   SanCovTraceConstCmpFunction[2] = M.getOrInsertFunction(
479       SanCovTraceConstCmp4, SanCovTraceCmpZeroExtAL, VoidTy, Int32Ty, Int32Ty);
480   SanCovTraceConstCmpFunction[3] =
481       M.getOrInsertFunction(SanCovTraceConstCmp8, VoidTy, Int64Ty, Int64Ty);
482 
483   // Loads.
484   SanCovLoadFunction[0] = M.getOrInsertFunction(SanCovLoad1, VoidTy, Int8PtrTy);
485   SanCovLoadFunction[1] =
486       M.getOrInsertFunction(SanCovLoad2, VoidTy, Int16PtrTy);
487   SanCovLoadFunction[2] =
488       M.getOrInsertFunction(SanCovLoad4, VoidTy, Int32PtrTy);
489   SanCovLoadFunction[3] =
490       M.getOrInsertFunction(SanCovLoad8, VoidTy, Int64PtrTy);
491   SanCovLoadFunction[4] =
492       M.getOrInsertFunction(SanCovLoad16, VoidTy, Int128PtrTy);
493   // Stores.
494   SanCovStoreFunction[0] =
495       M.getOrInsertFunction(SanCovStore1, VoidTy, Int8PtrTy);
496   SanCovStoreFunction[1] =
497       M.getOrInsertFunction(SanCovStore2, VoidTy, Int16PtrTy);
498   SanCovStoreFunction[2] =
499       M.getOrInsertFunction(SanCovStore4, VoidTy, Int32PtrTy);
500   SanCovStoreFunction[3] =
501       M.getOrInsertFunction(SanCovStore8, VoidTy, Int64PtrTy);
502   SanCovStoreFunction[4] =
503       M.getOrInsertFunction(SanCovStore16, VoidTy, Int128PtrTy);
504 
505   {
506     AttributeList AL;
507     AL = AL.addParamAttribute(*C, 0, Attribute::ZExt);
508     SanCovTraceDivFunction[0] =
509         M.getOrInsertFunction(SanCovTraceDiv4, AL, VoidTy, IRB.getInt32Ty());
510   }
511   SanCovTraceDivFunction[1] =
512       M.getOrInsertFunction(SanCovTraceDiv8, VoidTy, Int64Ty);
513   SanCovTraceGepFunction =
514       M.getOrInsertFunction(SanCovTraceGep, VoidTy, IntptrTy);
515   SanCovTraceSwitchFunction =
516       M.getOrInsertFunction(SanCovTraceSwitchName, VoidTy, Int64Ty, Int64PtrTy);
517 
518   Constant *SanCovLowestStackConstant =
519       M.getOrInsertGlobal(SanCovLowestStackName, IntptrTy);
520   SanCovLowestStack = dyn_cast<GlobalVariable>(SanCovLowestStackConstant);
521   if (!SanCovLowestStack || SanCovLowestStack->getValueType() != IntptrTy) {
522     C->emitError(StringRef("'") + SanCovLowestStackName +
523                  "' should not be declared by the user");
524     return true;
525   }
526   SanCovLowestStack->setThreadLocalMode(
527       GlobalValue::ThreadLocalMode::InitialExecTLSModel);
528   if (Options.StackDepth && !SanCovLowestStack->isDeclaration())
529     SanCovLowestStack->setInitializer(Constant::getAllOnesValue(IntptrTy));
530 
531   SanCovTracePC = M.getOrInsertFunction(SanCovTracePCName, VoidTy);
532   SanCovTracePCGuard =
533       M.getOrInsertFunction(SanCovTracePCGuardName, VoidTy, Int32PtrTy);
534 
535   for (auto &F : M)
536     instrumentFunction(F, DTCallback, PDTCallback);
537 
538   Function *Ctor = nullptr;
539 
540   if (FunctionGuardArray)
541     Ctor = CreateInitCallsForSections(M, SanCovModuleCtorTracePcGuardName,
542                                       SanCovTracePCGuardInitName, Int32Ty,
543                                       SanCovGuardsSectionName);
544   if (Function8bitCounterArray)
545     Ctor = CreateInitCallsForSections(M, SanCovModuleCtor8bitCountersName,
546                                       SanCov8bitCountersInitName, Int8Ty,
547                                       SanCovCountersSectionName);
548   if (FunctionBoolArray) {
549     Ctor = CreateInitCallsForSections(M, SanCovModuleCtorBoolFlagName,
550                                       SanCovBoolFlagInitName, Int1Ty,
551                                       SanCovBoolFlagSectionName);
552   }
553   if (Ctor && Options.PCTable) {
554     auto SecStartEnd = CreateSecStartEnd(M, SanCovPCsSectionName, IntptrTy);
555     FunctionCallee InitFunction = declareSanitizerInitFunction(
556         M, SanCovPCsInitName, {IntptrPtrTy, IntptrPtrTy});
557     IRBuilder<> IRBCtor(Ctor->getEntryBlock().getTerminator());
558     IRBCtor.CreateCall(InitFunction, {SecStartEnd.first, SecStartEnd.second});
559   }
560   appendToUsed(M, GlobalsToAppendToUsed);
561   appendToCompilerUsed(M, GlobalsToAppendToCompilerUsed);
562   return true;
563 }
564 
565 // True if block has successors and it dominates all of them.
566 static bool isFullDominator(const BasicBlock *BB, const DominatorTree *DT) {
567   if (succ_empty(BB))
568     return false;
569 
570   return llvm::all_of(successors(BB), [&](const BasicBlock *SUCC) {
571     return DT->dominates(BB, SUCC);
572   });
573 }
574 
575 // True if block has predecessors and it postdominates all of them.
576 static bool isFullPostDominator(const BasicBlock *BB,
577                                 const PostDominatorTree *PDT) {
578   if (pred_empty(BB))
579     return false;
580 
581   return llvm::all_of(predecessors(BB), [&](const BasicBlock *PRED) {
582     return PDT->dominates(BB, PRED);
583   });
584 }
585 
586 static bool shouldInstrumentBlock(const Function &F, const BasicBlock *BB,
587                                   const DominatorTree *DT,
588                                   const PostDominatorTree *PDT,
589                                   const SanitizerCoverageOptions &Options) {
590   // Don't insert coverage for blocks containing nothing but unreachable: we
591   // will never call __sanitizer_cov() for them, so counting them in
592   // NumberOfInstrumentedBlocks() might complicate calculation of code coverage
593   // percentage. Also, unreachable instructions frequently have no debug
594   // locations.
595   if (isa<UnreachableInst>(BB->getFirstNonPHIOrDbgOrLifetime()))
596     return false;
597 
598   // Don't insert coverage into blocks without a valid insertion point
599   // (catchswitch blocks).
600   if (BB->getFirstInsertionPt() == BB->end())
601     return false;
602 
603   if (Options.NoPrune || &F.getEntryBlock() == BB)
604     return true;
605 
606   if (Options.CoverageType == SanitizerCoverageOptions::SCK_Function &&
607       &F.getEntryBlock() != BB)
608     return false;
609 
610   // Do not instrument full dominators, or full post-dominators with multiple
611   // predecessors.
612   return !isFullDominator(BB, DT)
613     && !(isFullPostDominator(BB, PDT) && !BB->getSinglePredecessor());
614 }
615 
616 
617 // Returns true iff From->To is a backedge.
618 // A twist here is that we treat From->To as a backedge if
619 //   * To dominates From or
620 //   * To->UniqueSuccessor dominates From
621 static bool IsBackEdge(BasicBlock *From, BasicBlock *To,
622                        const DominatorTree *DT) {
623   if (DT->dominates(To, From))
624     return true;
625   if (auto Next = To->getUniqueSuccessor())
626     if (DT->dominates(Next, From))
627       return true;
628   return false;
629 }
630 
631 // Prunes uninteresting Cmp instrumentation:
632 //   * CMP instructions that feed into loop backedge branch.
633 //
634 // Note that Cmp pruning is controlled by the same flag as the
635 // BB pruning.
636 static bool IsInterestingCmp(ICmpInst *CMP, const DominatorTree *DT,
637                              const SanitizerCoverageOptions &Options) {
638   if (!Options.NoPrune)
639     if (CMP->hasOneUse())
640       if (auto BR = dyn_cast<BranchInst>(CMP->user_back()))
641         for (BasicBlock *B : BR->successors())
642           if (IsBackEdge(BR->getParent(), B, DT))
643             return false;
644   return true;
645 }
646 
647 void ModuleSanitizerCoverage::instrumentFunction(
648     Function &F, DomTreeCallback DTCallback, PostDomTreeCallback PDTCallback) {
649   if (F.empty())
650     return;
651   if (F.getName().find(".module_ctor") != std::string::npos)
652     return; // Should not instrument sanitizer init functions.
653   if (F.getName().startswith("__sanitizer_"))
654     return; // Don't instrument __sanitizer_* callbacks.
655   // Don't touch available_externally functions, their actual body is elewhere.
656   if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage)
657     return;
658   // Don't instrument MSVC CRT configuration helpers. They may run before normal
659   // initialization.
660   if (F.getName() == "__local_stdio_printf_options" ||
661       F.getName() == "__local_stdio_scanf_options")
662     return;
663   if (isa<UnreachableInst>(F.getEntryBlock().getTerminator()))
664     return;
665   // Don't instrument functions using SEH for now. Splitting basic blocks like
666   // we do for coverage breaks WinEHPrepare.
667   // FIXME: Remove this when SEH no longer uses landingpad pattern matching.
668   if (F.hasPersonalityFn() &&
669       isAsynchronousEHPersonality(classifyEHPersonality(F.getPersonalityFn())))
670     return;
671   if (Allowlist && !Allowlist->inSection("coverage", "fun", F.getName()))
672     return;
673   if (Blocklist && Blocklist->inSection("coverage", "fun", F.getName()))
674     return;
675   if (F.hasFnAttribute(Attribute::NoSanitizeCoverage))
676     return;
677   if (Options.CoverageType >= SanitizerCoverageOptions::SCK_Edge)
678     SplitAllCriticalEdges(F, CriticalEdgeSplittingOptions().setIgnoreUnreachableDests());
679   SmallVector<Instruction *, 8> IndirCalls;
680   SmallVector<BasicBlock *, 16> BlocksToInstrument;
681   SmallVector<Instruction *, 8> CmpTraceTargets;
682   SmallVector<Instruction *, 8> SwitchTraceTargets;
683   SmallVector<BinaryOperator *, 8> DivTraceTargets;
684   SmallVector<GetElementPtrInst *, 8> GepTraceTargets;
685   SmallVector<LoadInst *, 8> Loads;
686   SmallVector<StoreInst *, 8> Stores;
687 
688   const DominatorTree *DT = DTCallback(F);
689   const PostDominatorTree *PDT = PDTCallback(F);
690   bool IsLeafFunc = true;
691 
692   for (auto &BB : F) {
693     if (shouldInstrumentBlock(F, &BB, DT, PDT, Options))
694       BlocksToInstrument.push_back(&BB);
695     for (auto &Inst : BB) {
696       if (Options.IndirectCalls) {
697         CallBase *CB = dyn_cast<CallBase>(&Inst);
698         if (CB && CB->isIndirectCall())
699           IndirCalls.push_back(&Inst);
700       }
701       if (Options.TraceCmp) {
702         if (ICmpInst *CMP = dyn_cast<ICmpInst>(&Inst))
703           if (IsInterestingCmp(CMP, DT, Options))
704             CmpTraceTargets.push_back(&Inst);
705         if (isa<SwitchInst>(&Inst))
706           SwitchTraceTargets.push_back(&Inst);
707       }
708       if (Options.TraceDiv)
709         if (BinaryOperator *BO = dyn_cast<BinaryOperator>(&Inst))
710           if (BO->getOpcode() == Instruction::SDiv ||
711               BO->getOpcode() == Instruction::UDiv)
712             DivTraceTargets.push_back(BO);
713       if (Options.TraceGep)
714         if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(&Inst))
715           GepTraceTargets.push_back(GEP);
716       if (Options.TraceLoads)
717         if (LoadInst *LI = dyn_cast<LoadInst>(&Inst))
718           Loads.push_back(LI);
719       if (Options.TraceStores)
720         if (StoreInst *SI = dyn_cast<StoreInst>(&Inst))
721           Stores.push_back(SI);
722       if (Options.StackDepth)
723         if (isa<InvokeInst>(Inst) ||
724             (isa<CallInst>(Inst) && !isa<IntrinsicInst>(Inst)))
725           IsLeafFunc = false;
726     }
727   }
728 
729   InjectCoverage(F, BlocksToInstrument, IsLeafFunc);
730   InjectCoverageForIndirectCalls(F, IndirCalls);
731   InjectTraceForCmp(F, CmpTraceTargets);
732   InjectTraceForSwitch(F, SwitchTraceTargets);
733   InjectTraceForDiv(F, DivTraceTargets);
734   InjectTraceForGep(F, GepTraceTargets);
735   InjectTraceForLoadsAndStores(F, Loads, Stores);
736 }
737 
738 GlobalVariable *ModuleSanitizerCoverage::CreateFunctionLocalArrayInSection(
739     size_t NumElements, Function &F, Type *Ty, const char *Section) {
740   ArrayType *ArrayTy = ArrayType::get(Ty, NumElements);
741   auto Array = new GlobalVariable(
742       *CurModule, ArrayTy, false, GlobalVariable::PrivateLinkage,
743       Constant::getNullValue(ArrayTy), "__sancov_gen_");
744 
745   if (TargetTriple.supportsCOMDAT() &&
746       (TargetTriple.isOSBinFormatELF() || !F.isInterposable()))
747     if (auto Comdat = getOrCreateFunctionComdat(F, TargetTriple))
748       Array->setComdat(Comdat);
749   Array->setSection(getSectionName(Section));
750   Array->setAlignment(Align(DL->getTypeStoreSize(Ty).getFixedSize()));
751 
752   // sancov_pcs parallels the other metadata section(s). Optimizers (e.g.
753   // GlobalOpt/ConstantMerge) may not discard sancov_pcs and the other
754   // section(s) as a unit, so we conservatively retain all unconditionally in
755   // the compiler.
756   //
757   // With comdat (COFF/ELF), the linker can guarantee the associated sections
758   // will be retained or discarded as a unit, so llvm.compiler.used is
759   // sufficient. Otherwise, conservatively make all of them retained by the
760   // linker.
761   if (Array->hasComdat())
762     GlobalsToAppendToCompilerUsed.push_back(Array);
763   else
764     GlobalsToAppendToUsed.push_back(Array);
765 
766   return Array;
767 }
768 
769 GlobalVariable *
770 ModuleSanitizerCoverage::CreatePCArray(Function &F,
771                                        ArrayRef<BasicBlock *> AllBlocks) {
772   size_t N = AllBlocks.size();
773   assert(N);
774   SmallVector<Constant *, 32> PCs;
775   IRBuilder<> IRB(&*F.getEntryBlock().getFirstInsertionPt());
776   for (size_t i = 0; i < N; i++) {
777     if (&F.getEntryBlock() == AllBlocks[i]) {
778       PCs.push_back((Constant *)IRB.CreatePointerCast(&F, IntptrPtrTy));
779       PCs.push_back((Constant *)IRB.CreateIntToPtr(
780           ConstantInt::get(IntptrTy, 1), IntptrPtrTy));
781     } else {
782       PCs.push_back((Constant *)IRB.CreatePointerCast(
783           BlockAddress::get(AllBlocks[i]), IntptrPtrTy));
784       PCs.push_back((Constant *)IRB.CreateIntToPtr(
785           ConstantInt::get(IntptrTy, 0), IntptrPtrTy));
786     }
787   }
788   auto *PCArray = CreateFunctionLocalArrayInSection(N * 2, F, IntptrPtrTy,
789                                                     SanCovPCsSectionName);
790   PCArray->setInitializer(
791       ConstantArray::get(ArrayType::get(IntptrPtrTy, N * 2), PCs));
792   PCArray->setConstant(true);
793 
794   return PCArray;
795 }
796 
797 void ModuleSanitizerCoverage::CreateFunctionLocalArrays(
798     Function &F, ArrayRef<BasicBlock *> AllBlocks) {
799   if (Options.TracePCGuard)
800     FunctionGuardArray = CreateFunctionLocalArrayInSection(
801         AllBlocks.size(), F, Int32Ty, SanCovGuardsSectionName);
802 
803   if (Options.Inline8bitCounters)
804     Function8bitCounterArray = CreateFunctionLocalArrayInSection(
805         AllBlocks.size(), F, Int8Ty, SanCovCountersSectionName);
806   if (Options.InlineBoolFlag)
807     FunctionBoolArray = CreateFunctionLocalArrayInSection(
808         AllBlocks.size(), F, Int1Ty, SanCovBoolFlagSectionName);
809 
810   if (Options.PCTable)
811     FunctionPCsArray = CreatePCArray(F, AllBlocks);
812 }
813 
814 bool ModuleSanitizerCoverage::InjectCoverage(Function &F,
815                                              ArrayRef<BasicBlock *> AllBlocks,
816                                              bool IsLeafFunc) {
817   if (AllBlocks.empty()) return false;
818   CreateFunctionLocalArrays(F, AllBlocks);
819   for (size_t i = 0, N = AllBlocks.size(); i < N; i++)
820     InjectCoverageAtBlock(F, *AllBlocks[i], i, IsLeafFunc);
821   return true;
822 }
823 
824 // On every indirect call we call a run-time function
825 // __sanitizer_cov_indir_call* with two parameters:
826 //   - callee address,
827 //   - global cache array that contains CacheSize pointers (zero-initialized).
828 //     The cache is used to speed up recording the caller-callee pairs.
829 // The address of the caller is passed implicitly via caller PC.
830 // CacheSize is encoded in the name of the run-time function.
831 void ModuleSanitizerCoverage::InjectCoverageForIndirectCalls(
832     Function &F, ArrayRef<Instruction *> IndirCalls) {
833   if (IndirCalls.empty())
834     return;
835   assert(Options.TracePC || Options.TracePCGuard ||
836          Options.Inline8bitCounters || Options.InlineBoolFlag);
837   for (auto I : IndirCalls) {
838     IRBuilder<> IRB(I);
839     CallBase &CB = cast<CallBase>(*I);
840     Value *Callee = CB.getCalledOperand();
841     if (isa<InlineAsm>(Callee))
842       continue;
843     IRB.CreateCall(SanCovTracePCIndir, IRB.CreatePointerCast(Callee, IntptrTy));
844   }
845 }
846 
847 // For every switch statement we insert a call:
848 // __sanitizer_cov_trace_switch(CondValue,
849 //      {NumCases, ValueSizeInBits, Case0Value, Case1Value, Case2Value, ... })
850 
851 void ModuleSanitizerCoverage::InjectTraceForSwitch(
852     Function &, ArrayRef<Instruction *> SwitchTraceTargets) {
853   for (auto I : SwitchTraceTargets) {
854     if (SwitchInst *SI = dyn_cast<SwitchInst>(I)) {
855       IRBuilder<> IRB(I);
856       SmallVector<Constant *, 16> Initializers;
857       Value *Cond = SI->getCondition();
858       if (Cond->getType()->getScalarSizeInBits() >
859           Int64Ty->getScalarSizeInBits())
860         continue;
861       Initializers.push_back(ConstantInt::get(Int64Ty, SI->getNumCases()));
862       Initializers.push_back(
863           ConstantInt::get(Int64Ty, Cond->getType()->getScalarSizeInBits()));
864       if (Cond->getType()->getScalarSizeInBits() <
865           Int64Ty->getScalarSizeInBits())
866         Cond = IRB.CreateIntCast(Cond, Int64Ty, false);
867       for (auto It : SI->cases()) {
868         Constant *C = It.getCaseValue();
869         if (C->getType()->getScalarSizeInBits() <
870             Int64Ty->getScalarSizeInBits())
871           C = ConstantExpr::getCast(CastInst::ZExt, It.getCaseValue(), Int64Ty);
872         Initializers.push_back(C);
873       }
874       llvm::sort(drop_begin(Initializers, 2),
875                  [](const Constant *A, const Constant *B) {
876                    return cast<ConstantInt>(A)->getLimitedValue() <
877                           cast<ConstantInt>(B)->getLimitedValue();
878                  });
879       ArrayType *ArrayOfInt64Ty = ArrayType::get(Int64Ty, Initializers.size());
880       GlobalVariable *GV = new GlobalVariable(
881           *CurModule, ArrayOfInt64Ty, false, GlobalVariable::InternalLinkage,
882           ConstantArray::get(ArrayOfInt64Ty, Initializers),
883           "__sancov_gen_cov_switch_values");
884       IRB.CreateCall(SanCovTraceSwitchFunction,
885                      {Cond, IRB.CreatePointerCast(GV, Int64PtrTy)});
886     }
887   }
888 }
889 
890 void ModuleSanitizerCoverage::InjectTraceForDiv(
891     Function &, ArrayRef<BinaryOperator *> DivTraceTargets) {
892   for (auto BO : DivTraceTargets) {
893     IRBuilder<> IRB(BO);
894     Value *A1 = BO->getOperand(1);
895     if (isa<ConstantInt>(A1)) continue;
896     if (!A1->getType()->isIntegerTy())
897       continue;
898     uint64_t TypeSize = DL->getTypeStoreSizeInBits(A1->getType());
899     int CallbackIdx = TypeSize == 32 ? 0 :
900         TypeSize == 64 ? 1 : -1;
901     if (CallbackIdx < 0) continue;
902     auto Ty = Type::getIntNTy(*C, TypeSize);
903     IRB.CreateCall(SanCovTraceDivFunction[CallbackIdx],
904                    {IRB.CreateIntCast(A1, Ty, true)});
905   }
906 }
907 
908 void ModuleSanitizerCoverage::InjectTraceForGep(
909     Function &, ArrayRef<GetElementPtrInst *> GepTraceTargets) {
910   for (auto GEP : GepTraceTargets) {
911     IRBuilder<> IRB(GEP);
912     for (Use &Idx : GEP->indices())
913       if (!isa<ConstantInt>(Idx) && Idx->getType()->isIntegerTy())
914         IRB.CreateCall(SanCovTraceGepFunction,
915                        {IRB.CreateIntCast(Idx, IntptrTy, true)});
916   }
917 }
918 
919 void ModuleSanitizerCoverage::InjectTraceForLoadsAndStores(
920     Function &, ArrayRef<LoadInst *> Loads, ArrayRef<StoreInst *> Stores) {
921   auto CallbackIdx = [&](Type *ElementTy) -> int {
922     uint64_t TypeSize = DL->getTypeStoreSizeInBits(ElementTy);
923     return TypeSize == 8     ? 0
924            : TypeSize == 16  ? 1
925            : TypeSize == 32  ? 2
926            : TypeSize == 64  ? 3
927            : TypeSize == 128 ? 4
928                              : -1;
929   };
930   Type *PointerType[5] = {Int8PtrTy, Int16PtrTy, Int32PtrTy, Int64PtrTy,
931                           Int128PtrTy};
932   for (auto LI : Loads) {
933     IRBuilder<> IRB(LI);
934     auto Ptr = LI->getPointerOperand();
935     int Idx = CallbackIdx(LI->getType());
936     if (Idx < 0)
937       continue;
938     IRB.CreateCall(SanCovLoadFunction[Idx],
939                    IRB.CreatePointerCast(Ptr, PointerType[Idx]));
940   }
941   for (auto SI : Stores) {
942     IRBuilder<> IRB(SI);
943     auto Ptr = SI->getPointerOperand();
944     int Idx = CallbackIdx(SI->getValueOperand()->getType());
945     if (Idx < 0)
946       continue;
947     IRB.CreateCall(SanCovStoreFunction[Idx],
948                    IRB.CreatePointerCast(Ptr, PointerType[Idx]));
949   }
950 }
951 
952 void ModuleSanitizerCoverage::InjectTraceForCmp(
953     Function &, ArrayRef<Instruction *> CmpTraceTargets) {
954   for (auto I : CmpTraceTargets) {
955     if (ICmpInst *ICMP = dyn_cast<ICmpInst>(I)) {
956       IRBuilder<> IRB(ICMP);
957       Value *A0 = ICMP->getOperand(0);
958       Value *A1 = ICMP->getOperand(1);
959       if (!A0->getType()->isIntegerTy())
960         continue;
961       uint64_t TypeSize = DL->getTypeStoreSizeInBits(A0->getType());
962       int CallbackIdx = TypeSize == 8 ? 0 :
963                         TypeSize == 16 ? 1 :
964                         TypeSize == 32 ? 2 :
965                         TypeSize == 64 ? 3 : -1;
966       if (CallbackIdx < 0) continue;
967       // __sanitizer_cov_trace_cmp((type_size << 32) | predicate, A0, A1);
968       auto CallbackFunc = SanCovTraceCmpFunction[CallbackIdx];
969       bool FirstIsConst = isa<ConstantInt>(A0);
970       bool SecondIsConst = isa<ConstantInt>(A1);
971       // If both are const, then we don't need such a comparison.
972       if (FirstIsConst && SecondIsConst) continue;
973       // If only one is const, then make it the first callback argument.
974       if (FirstIsConst || SecondIsConst) {
975         CallbackFunc = SanCovTraceConstCmpFunction[CallbackIdx];
976         if (SecondIsConst)
977           std::swap(A0, A1);
978       }
979 
980       auto Ty = Type::getIntNTy(*C, TypeSize);
981       IRB.CreateCall(CallbackFunc, {IRB.CreateIntCast(A0, Ty, true),
982               IRB.CreateIntCast(A1, Ty, true)});
983     }
984   }
985 }
986 
987 void ModuleSanitizerCoverage::InjectCoverageAtBlock(Function &F, BasicBlock &BB,
988                                                     size_t Idx,
989                                                     bool IsLeafFunc) {
990   BasicBlock::iterator IP = BB.getFirstInsertionPt();
991   bool IsEntryBB = &BB == &F.getEntryBlock();
992   DebugLoc EntryLoc;
993   if (IsEntryBB) {
994     if (auto SP = F.getSubprogram())
995       EntryLoc = DILocation::get(SP->getContext(), SP->getScopeLine(), 0, SP);
996     // Keep static allocas and llvm.localescape calls in the entry block.  Even
997     // if we aren't splitting the block, it's nice for allocas to be before
998     // calls.
999     IP = PrepareToSplitEntryBlock(BB, IP);
1000   } else {
1001     EntryLoc = IP->getDebugLoc();
1002     if (!EntryLoc)
1003       if (auto *SP = F.getSubprogram())
1004         EntryLoc = DILocation::get(SP->getContext(), 0, 0, SP);
1005   }
1006 
1007   IRBuilder<> IRB(&*IP);
1008   IRB.SetCurrentDebugLocation(EntryLoc);
1009   if (Options.TracePC) {
1010     IRB.CreateCall(SanCovTracePC)
1011         ->setCannotMerge(); // gets the PC using GET_CALLER_PC.
1012   }
1013   if (Options.TracePCGuard) {
1014     auto GuardPtr = IRB.CreateIntToPtr(
1015         IRB.CreateAdd(IRB.CreatePointerCast(FunctionGuardArray, IntptrTy),
1016                       ConstantInt::get(IntptrTy, Idx * 4)),
1017         Int32PtrTy);
1018     IRB.CreateCall(SanCovTracePCGuard, GuardPtr)->setCannotMerge();
1019   }
1020   if (Options.Inline8bitCounters) {
1021     auto CounterPtr = IRB.CreateGEP(
1022         Function8bitCounterArray->getValueType(), Function8bitCounterArray,
1023         {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)});
1024     auto Load = IRB.CreateLoad(Int8Ty, CounterPtr);
1025     auto Inc = IRB.CreateAdd(Load, ConstantInt::get(Int8Ty, 1));
1026     auto Store = IRB.CreateStore(Inc, CounterPtr);
1027     SetNoSanitizeMetadata(Load);
1028     SetNoSanitizeMetadata(Store);
1029   }
1030   if (Options.InlineBoolFlag) {
1031     auto FlagPtr = IRB.CreateGEP(
1032         FunctionBoolArray->getValueType(), FunctionBoolArray,
1033         {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)});
1034     auto Load = IRB.CreateLoad(Int1Ty, FlagPtr);
1035     auto ThenTerm =
1036         SplitBlockAndInsertIfThen(IRB.CreateIsNull(Load), &*IP, false);
1037     IRBuilder<> ThenIRB(ThenTerm);
1038     auto Store = ThenIRB.CreateStore(ConstantInt::getTrue(Int1Ty), FlagPtr);
1039     SetNoSanitizeMetadata(Load);
1040     SetNoSanitizeMetadata(Store);
1041   }
1042   if (Options.StackDepth && IsEntryBB && !IsLeafFunc) {
1043     // Check stack depth.  If it's the deepest so far, record it.
1044     Module *M = F.getParent();
1045     Function *GetFrameAddr = Intrinsic::getDeclaration(
1046         M, Intrinsic::frameaddress,
1047         IRB.getInt8PtrTy(M->getDataLayout().getAllocaAddrSpace()));
1048     auto FrameAddrPtr =
1049         IRB.CreateCall(GetFrameAddr, {Constant::getNullValue(Int32Ty)});
1050     auto FrameAddrInt = IRB.CreatePtrToInt(FrameAddrPtr, IntptrTy);
1051     auto LowestStack = IRB.CreateLoad(IntptrTy, SanCovLowestStack);
1052     auto IsStackLower = IRB.CreateICmpULT(FrameAddrInt, LowestStack);
1053     auto ThenTerm = SplitBlockAndInsertIfThen(IsStackLower, &*IP, false);
1054     IRBuilder<> ThenIRB(ThenTerm);
1055     auto Store = ThenIRB.CreateStore(FrameAddrInt, SanCovLowestStack);
1056     SetNoSanitizeMetadata(LowestStack);
1057     SetNoSanitizeMetadata(Store);
1058   }
1059 }
1060 
1061 std::string
1062 ModuleSanitizerCoverage::getSectionName(const std::string &Section) const {
1063   if (TargetTriple.isOSBinFormatCOFF()) {
1064     if (Section == SanCovCountersSectionName)
1065       return ".SCOV$CM";
1066     if (Section == SanCovBoolFlagSectionName)
1067       return ".SCOV$BM";
1068     if (Section == SanCovPCsSectionName)
1069       return ".SCOVP$M";
1070     return ".SCOV$GM"; // For SanCovGuardsSectionName.
1071   }
1072   if (TargetTriple.isOSBinFormatMachO())
1073     return "__DATA,__" + Section;
1074   return "__" + Section;
1075 }
1076 
1077 std::string
1078 ModuleSanitizerCoverage::getSectionStart(const std::string &Section) const {
1079   if (TargetTriple.isOSBinFormatMachO())
1080     return "\1section$start$__DATA$__" + Section;
1081   return "__start___" + Section;
1082 }
1083 
1084 std::string
1085 ModuleSanitizerCoverage::getSectionEnd(const std::string &Section) const {
1086   if (TargetTriple.isOSBinFormatMachO())
1087     return "\1section$end$__DATA$__" + Section;
1088   return "__stop___" + Section;
1089 }
1090 
1091 char ModuleSanitizerCoverageLegacyPass::ID = 0;
1092 INITIALIZE_PASS_BEGIN(ModuleSanitizerCoverageLegacyPass, "sancov",
1093                       "Pass for instrumenting coverage on functions", false,
1094                       false)
1095 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
1096 INITIALIZE_PASS_DEPENDENCY(PostDominatorTreeWrapperPass)
1097 INITIALIZE_PASS_END(ModuleSanitizerCoverageLegacyPass, "sancov",
1098                     "Pass for instrumenting coverage on functions", false,
1099                     false)
1100 ModulePass *llvm::createModuleSanitizerCoverageLegacyPassPass(
1101     const SanitizerCoverageOptions &Options,
1102     const std::vector<std::string> &AllowlistFiles,
1103     const std::vector<std::string> &BlocklistFiles) {
1104   return new ModuleSanitizerCoverageLegacyPass(Options, AllowlistFiles,
1105                                                BlocklistFiles);
1106 }
1107