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/Constant.h"
20 #include "llvm/IR/DataLayout.h"
21 #include "llvm/IR/Dominators.h"
22 #include "llvm/IR/Function.h"
23 #include "llvm/IR/GlobalVariable.h"
24 #include "llvm/IR/IRBuilder.h"
25 #include "llvm/IR/IntrinsicInst.h"
26 #include "llvm/IR/Intrinsics.h"
27 #include "llvm/IR/LLVMContext.h"
28 #include "llvm/IR/Module.h"
29 #include "llvm/IR/Type.h"
30 #include "llvm/InitializePasses.h"
31 #include "llvm/Support/CommandLine.h"
32 #include "llvm/Support/SpecialCaseList.h"
33 #include "llvm/Support/VirtualFileSystem.h"
34 #include "llvm/Transforms/Instrumentation.h"
35 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
36 #include "llvm/Transforms/Utils/ModuleUtils.h"
37
38 using namespace llvm;
39
40 #define DEBUG_TYPE "sancov"
41
42 const char SanCovTracePCIndirName[] = "__sanitizer_cov_trace_pc_indir";
43 const char SanCovTracePCName[] = "__sanitizer_cov_trace_pc";
44 const char SanCovTraceCmp1[] = "__sanitizer_cov_trace_cmp1";
45 const char SanCovTraceCmp2[] = "__sanitizer_cov_trace_cmp2";
46 const char SanCovTraceCmp4[] = "__sanitizer_cov_trace_cmp4";
47 const char SanCovTraceCmp8[] = "__sanitizer_cov_trace_cmp8";
48 const char SanCovTraceConstCmp1[] = "__sanitizer_cov_trace_const_cmp1";
49 const char SanCovTraceConstCmp2[] = "__sanitizer_cov_trace_const_cmp2";
50 const char SanCovTraceConstCmp4[] = "__sanitizer_cov_trace_const_cmp4";
51 const char SanCovTraceConstCmp8[] = "__sanitizer_cov_trace_const_cmp8";
52 const char SanCovLoad1[] = "__sanitizer_cov_load1";
53 const char SanCovLoad2[] = "__sanitizer_cov_load2";
54 const char SanCovLoad4[] = "__sanitizer_cov_load4";
55 const char SanCovLoad8[] = "__sanitizer_cov_load8";
56 const char SanCovLoad16[] = "__sanitizer_cov_load16";
57 const char SanCovStore1[] = "__sanitizer_cov_store1";
58 const char SanCovStore2[] = "__sanitizer_cov_store2";
59 const char SanCovStore4[] = "__sanitizer_cov_store4";
60 const char SanCovStore8[] = "__sanitizer_cov_store8";
61 const char SanCovStore16[] = "__sanitizer_cov_store16";
62 const char SanCovTraceDiv4[] = "__sanitizer_cov_trace_div4";
63 const char SanCovTraceDiv8[] = "__sanitizer_cov_trace_div8";
64 const char SanCovTraceGep[] = "__sanitizer_cov_trace_gep";
65 const char SanCovTraceSwitchName[] = "__sanitizer_cov_trace_switch";
66 const char SanCovModuleCtorTracePcGuardName[] =
67 "sancov.module_ctor_trace_pc_guard";
68 const char SanCovModuleCtor8bitCountersName[] =
69 "sancov.module_ctor_8bit_counters";
70 const char SanCovModuleCtorBoolFlagName[] = "sancov.module_ctor_bool_flag";
71 static const uint64_t SanCtorAndDtorPriority = 2;
72
73 const char SanCovTracePCGuardName[] = "__sanitizer_cov_trace_pc_guard";
74 const char SanCovTracePCGuardInitName[] = "__sanitizer_cov_trace_pc_guard_init";
75 const char SanCov8bitCountersInitName[] = "__sanitizer_cov_8bit_counters_init";
76 const char SanCovBoolFlagInitName[] = "__sanitizer_cov_bool_flag_init";
77 const char SanCovPCsInitName[] = "__sanitizer_cov_pcs_init";
78
79 const char SanCovGuardsSectionName[] = "sancov_guards";
80 const char SanCovCountersSectionName[] = "sancov_cntrs";
81 const char SanCovBoolFlagSectionName[] = "sancov_bools";
82 const char SanCovPCsSectionName[] = "sancov_pcs";
83
84 const char SanCovLowestStackName[] = "__sancov_lowest_stack";
85
86 static cl::opt<int> ClCoverageLevel(
87 "sanitizer-coverage-level",
88 cl::desc("Sanitizer Coverage. 0: none, 1: entry block, 2: all blocks, "
89 "3: all blocks and critical edges"),
90 cl::Hidden, cl::init(0));
91
92 static cl::opt<bool> ClTracePC("sanitizer-coverage-trace-pc",
93 cl::desc("Experimental pc tracing"), cl::Hidden,
94 cl::init(false));
95
96 static cl::opt<bool> ClTracePCGuard("sanitizer-coverage-trace-pc-guard",
97 cl::desc("pc tracing with a guard"),
98 cl::Hidden, cl::init(false));
99
100 // If true, we create a global variable that contains PCs of all instrumented
101 // BBs, put this global into a named section, and pass this section's bounds
102 // to __sanitizer_cov_pcs_init.
103 // This way the coverage instrumentation does not need to acquire the PCs
104 // at run-time. Works with trace-pc-guard, inline-8bit-counters, and
105 // inline-bool-flag.
106 static cl::opt<bool> ClCreatePCTable("sanitizer-coverage-pc-table",
107 cl::desc("create a static PC table"),
108 cl::Hidden, cl::init(false));
109
110 static cl::opt<bool>
111 ClInline8bitCounters("sanitizer-coverage-inline-8bit-counters",
112 cl::desc("increments 8-bit counter for every edge"),
113 cl::Hidden, cl::init(false));
114
115 static cl::opt<bool>
116 ClInlineBoolFlag("sanitizer-coverage-inline-bool-flag",
117 cl::desc("sets a boolean flag for every edge"), cl::Hidden,
118 cl::init(false));
119
120 static cl::opt<bool>
121 ClCMPTracing("sanitizer-coverage-trace-compares",
122 cl::desc("Tracing of CMP and similar instructions"),
123 cl::Hidden, cl::init(false));
124
125 static cl::opt<bool> ClDIVTracing("sanitizer-coverage-trace-divs",
126 cl::desc("Tracing of DIV instructions"),
127 cl::Hidden, cl::init(false));
128
129 static cl::opt<bool> ClLoadTracing("sanitizer-coverage-trace-loads",
130 cl::desc("Tracing of load instructions"),
131 cl::Hidden, cl::init(false));
132
133 static cl::opt<bool> ClStoreTracing("sanitizer-coverage-trace-stores",
134 cl::desc("Tracing of store instructions"),
135 cl::Hidden, cl::init(false));
136
137 static cl::opt<bool> ClGEPTracing("sanitizer-coverage-trace-geps",
138 cl::desc("Tracing of GEP instructions"),
139 cl::Hidden, cl::init(false));
140
141 static cl::opt<bool>
142 ClPruneBlocks("sanitizer-coverage-prune-blocks",
143 cl::desc("Reduce the number of instrumented blocks"),
144 cl::Hidden, cl::init(true));
145
146 static cl::opt<bool> ClStackDepth("sanitizer-coverage-stack-depth",
147 cl::desc("max stack depth tracing"),
148 cl::Hidden, cl::init(false));
149
150 namespace {
151
getOptions(int LegacyCoverageLevel)152 SanitizerCoverageOptions getOptions(int LegacyCoverageLevel) {
153 SanitizerCoverageOptions Res;
154 switch (LegacyCoverageLevel) {
155 case 0:
156 Res.CoverageType = SanitizerCoverageOptions::SCK_None;
157 break;
158 case 1:
159 Res.CoverageType = SanitizerCoverageOptions::SCK_Function;
160 break;
161 case 2:
162 Res.CoverageType = SanitizerCoverageOptions::SCK_BB;
163 break;
164 case 3:
165 Res.CoverageType = SanitizerCoverageOptions::SCK_Edge;
166 break;
167 case 4:
168 Res.CoverageType = SanitizerCoverageOptions::SCK_Edge;
169 Res.IndirectCalls = true;
170 break;
171 }
172 return Res;
173 }
174
OverrideFromCL(SanitizerCoverageOptions Options)175 SanitizerCoverageOptions OverrideFromCL(SanitizerCoverageOptions Options) {
176 // Sets CoverageType and IndirectCalls.
177 SanitizerCoverageOptions CLOpts = getOptions(ClCoverageLevel);
178 Options.CoverageType = std::max(Options.CoverageType, CLOpts.CoverageType);
179 Options.IndirectCalls |= CLOpts.IndirectCalls;
180 Options.TraceCmp |= ClCMPTracing;
181 Options.TraceDiv |= ClDIVTracing;
182 Options.TraceGep |= ClGEPTracing;
183 Options.TracePC |= ClTracePC;
184 Options.TracePCGuard |= ClTracePCGuard;
185 Options.Inline8bitCounters |= ClInline8bitCounters;
186 Options.InlineBoolFlag |= ClInlineBoolFlag;
187 Options.PCTable |= ClCreatePCTable;
188 Options.NoPrune |= !ClPruneBlocks;
189 Options.StackDepth |= ClStackDepth;
190 Options.TraceLoads |= ClLoadTracing;
191 Options.TraceStores |= ClStoreTracing;
192 if (!Options.TracePCGuard && !Options.TracePC &&
193 !Options.Inline8bitCounters && !Options.StackDepth &&
194 !Options.InlineBoolFlag && !Options.TraceLoads && !Options.TraceStores)
195 Options.TracePCGuard = true; // TracePCGuard is default.
196 return Options;
197 }
198
199 using DomTreeCallback = function_ref<const DominatorTree *(Function &F)>;
200 using PostDomTreeCallback =
201 function_ref<const PostDominatorTree *(Function &F)>;
202
203 class ModuleSanitizerCoverage {
204 public:
ModuleSanitizerCoverage(const SanitizerCoverageOptions & Options=SanitizerCoverageOptions (),const SpecialCaseList * Allowlist=nullptr,const SpecialCaseList * Blocklist=nullptr)205 ModuleSanitizerCoverage(
206 const SanitizerCoverageOptions &Options = SanitizerCoverageOptions(),
207 const SpecialCaseList *Allowlist = nullptr,
208 const SpecialCaseList *Blocklist = nullptr)
209 : Options(OverrideFromCL(Options)), Allowlist(Allowlist),
210 Blocklist(Blocklist) {}
211 bool instrumentModule(Module &M, DomTreeCallback DTCallback,
212 PostDomTreeCallback PDTCallback);
213
214 private:
215 void instrumentFunction(Function &F, DomTreeCallback DTCallback,
216 PostDomTreeCallback PDTCallback);
217 void InjectCoverageForIndirectCalls(Function &F,
218 ArrayRef<Instruction *> IndirCalls);
219 void InjectTraceForCmp(Function &F, ArrayRef<Instruction *> CmpTraceTargets);
220 void InjectTraceForDiv(Function &F,
221 ArrayRef<BinaryOperator *> DivTraceTargets);
222 void InjectTraceForGep(Function &F,
223 ArrayRef<GetElementPtrInst *> GepTraceTargets);
224 void InjectTraceForLoadsAndStores(Function &F, ArrayRef<LoadInst *> Loads,
225 ArrayRef<StoreInst *> Stores);
226 void InjectTraceForSwitch(Function &F,
227 ArrayRef<Instruction *> SwitchTraceTargets);
228 bool InjectCoverage(Function &F, ArrayRef<BasicBlock *> AllBlocks,
229 bool IsLeafFunc = true);
230 GlobalVariable *CreateFunctionLocalArrayInSection(size_t NumElements,
231 Function &F, Type *Ty,
232 const char *Section);
233 GlobalVariable *CreatePCArray(Function &F, ArrayRef<BasicBlock *> AllBlocks);
234 void CreateFunctionLocalArrays(Function &F, ArrayRef<BasicBlock *> AllBlocks);
235 void InjectCoverageAtBlock(Function &F, BasicBlock &BB, size_t Idx,
236 bool IsLeafFunc = true);
237 Function *CreateInitCallsForSections(Module &M, const char *CtorName,
238 const char *InitFunctionName, Type *Ty,
239 const char *Section);
240 std::pair<Value *, Value *> CreateSecStartEnd(Module &M, const char *Section,
241 Type *Ty);
242
SetNoSanitizeMetadata(Instruction * I)243 void SetNoSanitizeMetadata(Instruction *I) {
244 I->setMetadata(LLVMContext::MD_nosanitize, MDNode::get(*C, None));
245 }
246
247 std::string getSectionName(const std::string &Section) const;
248 std::string getSectionStart(const std::string &Section) const;
249 std::string getSectionEnd(const std::string &Section) const;
250 FunctionCallee SanCovTracePCIndir;
251 FunctionCallee SanCovTracePC, SanCovTracePCGuard;
252 std::array<FunctionCallee, 4> SanCovTraceCmpFunction;
253 std::array<FunctionCallee, 4> SanCovTraceConstCmpFunction;
254 std::array<FunctionCallee, 5> SanCovLoadFunction;
255 std::array<FunctionCallee, 5> SanCovStoreFunction;
256 std::array<FunctionCallee, 2> SanCovTraceDivFunction;
257 FunctionCallee SanCovTraceGepFunction;
258 FunctionCallee SanCovTraceSwitchFunction;
259 GlobalVariable *SanCovLowestStack;
260 Type *Int128PtrTy, *IntptrTy, *IntptrPtrTy, *Int64Ty, *Int64PtrTy, *Int32Ty,
261 *Int32PtrTy, *Int16PtrTy, *Int16Ty, *Int8Ty, *Int8PtrTy, *Int1Ty,
262 *Int1PtrTy;
263 Module *CurModule;
264 std::string CurModuleUniqueId;
265 Triple TargetTriple;
266 LLVMContext *C;
267 const DataLayout *DL;
268
269 GlobalVariable *FunctionGuardArray; // for trace-pc-guard.
270 GlobalVariable *Function8bitCounterArray; // for inline-8bit-counters.
271 GlobalVariable *FunctionBoolArray; // for inline-bool-flag.
272 GlobalVariable *FunctionPCsArray; // for pc-table.
273 SmallVector<GlobalValue *, 20> GlobalsToAppendToUsed;
274 SmallVector<GlobalValue *, 20> GlobalsToAppendToCompilerUsed;
275
276 SanitizerCoverageOptions Options;
277
278 const SpecialCaseList *Allowlist;
279 const SpecialCaseList *Blocklist;
280 };
281 } // namespace
282
run(Module & M,ModuleAnalysisManager & MAM)283 PreservedAnalyses ModuleSanitizerCoveragePass::run(Module &M,
284 ModuleAnalysisManager &MAM) {
285 ModuleSanitizerCoverage ModuleSancov(Options, Allowlist.get(),
286 Blocklist.get());
287 auto &FAM = MAM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
288 auto DTCallback = [&FAM](Function &F) -> const DominatorTree * {
289 return &FAM.getResult<DominatorTreeAnalysis>(F);
290 };
291 auto PDTCallback = [&FAM](Function &F) -> const PostDominatorTree * {
292 return &FAM.getResult<PostDominatorTreeAnalysis>(F);
293 };
294 if (ModuleSancov.instrumentModule(M, DTCallback, PDTCallback))
295 return PreservedAnalyses::none();
296 return PreservedAnalyses::all();
297 }
298
299 std::pair<Value *, Value *>
CreateSecStartEnd(Module & M,const char * Section,Type * Ty)300 ModuleSanitizerCoverage::CreateSecStartEnd(Module &M, const char *Section,
301 Type *Ty) {
302 // Use ExternalWeak so that if all sections are discarded due to section
303 // garbage collection, the linker will not report undefined symbol errors.
304 // Windows defines the start/stop symbols in compiler-rt so no need for
305 // ExternalWeak.
306 GlobalValue::LinkageTypes Linkage = TargetTriple.isOSBinFormatCOFF()
307 ? GlobalVariable::ExternalLinkage
308 : GlobalVariable::ExternalWeakLinkage;
309 GlobalVariable *SecStart =
310 new GlobalVariable(M, Ty, false, Linkage, nullptr,
311 getSectionStart(Section));
312 SecStart->setVisibility(GlobalValue::HiddenVisibility);
313 GlobalVariable *SecEnd =
314 new GlobalVariable(M, Ty, false, Linkage, nullptr,
315 getSectionEnd(Section));
316 SecEnd->setVisibility(GlobalValue::HiddenVisibility);
317 IRBuilder<> IRB(M.getContext());
318 if (!TargetTriple.isOSBinFormatCOFF())
319 return std::make_pair(SecStart, SecEnd);
320
321 // Account for the fact that on windows-msvc __start_* symbols actually
322 // point to a uint64_t before the start of the array.
323 auto SecStartI8Ptr = IRB.CreatePointerCast(SecStart, Int8PtrTy);
324 auto GEP = IRB.CreateGEP(Int8Ty, SecStartI8Ptr,
325 ConstantInt::get(IntptrTy, sizeof(uint64_t)));
326 return std::make_pair(IRB.CreatePointerCast(GEP, PointerType::getUnqual(Ty)),
327 SecEnd);
328 }
329
CreateInitCallsForSections(Module & M,const char * CtorName,const char * InitFunctionName,Type * Ty,const char * Section)330 Function *ModuleSanitizerCoverage::CreateInitCallsForSections(
331 Module &M, const char *CtorName, const char *InitFunctionName, Type *Ty,
332 const char *Section) {
333 auto SecStartEnd = CreateSecStartEnd(M, Section, Ty);
334 auto SecStart = SecStartEnd.first;
335 auto SecEnd = SecStartEnd.second;
336 Function *CtorFunc;
337 Type *PtrTy = PointerType::getUnqual(Ty);
338 std::tie(CtorFunc, std::ignore) = createSanitizerCtorAndInitFunctions(
339 M, CtorName, InitFunctionName, {PtrTy, PtrTy}, {SecStart, SecEnd});
340 assert(CtorFunc->getName() == CtorName);
341
342 if (TargetTriple.supportsCOMDAT()) {
343 // Use comdat to dedup CtorFunc.
344 CtorFunc->setComdat(M.getOrInsertComdat(CtorName));
345 appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority, CtorFunc);
346 } else {
347 appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority);
348 }
349
350 if (TargetTriple.isOSBinFormatCOFF()) {
351 // In COFF files, if the contructors are set as COMDAT (they are because
352 // COFF supports COMDAT) and the linker flag /OPT:REF (strip unreferenced
353 // functions and data) is used, the constructors get stripped. To prevent
354 // this, give the constructors weak ODR linkage and ensure the linker knows
355 // to include the sancov constructor. This way the linker can deduplicate
356 // the constructors but always leave one copy.
357 CtorFunc->setLinkage(GlobalValue::WeakODRLinkage);
358 }
359 return CtorFunc;
360 }
361
instrumentModule(Module & M,DomTreeCallback DTCallback,PostDomTreeCallback PDTCallback)362 bool ModuleSanitizerCoverage::instrumentModule(
363 Module &M, DomTreeCallback DTCallback, PostDomTreeCallback PDTCallback) {
364 if (Options.CoverageType == SanitizerCoverageOptions::SCK_None)
365 return false;
366 if (Allowlist &&
367 !Allowlist->inSection("coverage", "src", M.getSourceFileName()))
368 return false;
369 if (Blocklist &&
370 Blocklist->inSection("coverage", "src", M.getSourceFileName()))
371 return false;
372 C = &(M.getContext());
373 DL = &M.getDataLayout();
374 CurModule = &M;
375 CurModuleUniqueId = getUniqueModuleId(CurModule);
376 TargetTriple = Triple(M.getTargetTriple());
377 FunctionGuardArray = nullptr;
378 Function8bitCounterArray = nullptr;
379 FunctionBoolArray = nullptr;
380 FunctionPCsArray = nullptr;
381 IntptrTy = Type::getIntNTy(*C, DL->getPointerSizeInBits());
382 IntptrPtrTy = PointerType::getUnqual(IntptrTy);
383 Type *VoidTy = Type::getVoidTy(*C);
384 IRBuilder<> IRB(*C);
385 Int128PtrTy = PointerType::getUnqual(IRB.getInt128Ty());
386 Int64PtrTy = PointerType::getUnqual(IRB.getInt64Ty());
387 Int16PtrTy = PointerType::getUnqual(IRB.getInt16Ty());
388 Int32PtrTy = PointerType::getUnqual(IRB.getInt32Ty());
389 Int8PtrTy = PointerType::getUnqual(IRB.getInt8Ty());
390 Int1PtrTy = PointerType::getUnqual(IRB.getInt1Ty());
391 Int64Ty = IRB.getInt64Ty();
392 Int32Ty = IRB.getInt32Ty();
393 Int16Ty = IRB.getInt16Ty();
394 Int8Ty = IRB.getInt8Ty();
395 Int1Ty = IRB.getInt1Ty();
396
397 SanCovTracePCIndir =
398 M.getOrInsertFunction(SanCovTracePCIndirName, VoidTy, IntptrTy);
399 // Make sure smaller parameters are zero-extended to i64 if required by the
400 // target ABI.
401 AttributeList SanCovTraceCmpZeroExtAL;
402 SanCovTraceCmpZeroExtAL =
403 SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 0, Attribute::ZExt);
404 SanCovTraceCmpZeroExtAL =
405 SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 1, Attribute::ZExt);
406
407 SanCovTraceCmpFunction[0] =
408 M.getOrInsertFunction(SanCovTraceCmp1, SanCovTraceCmpZeroExtAL, VoidTy,
409 IRB.getInt8Ty(), IRB.getInt8Ty());
410 SanCovTraceCmpFunction[1] =
411 M.getOrInsertFunction(SanCovTraceCmp2, SanCovTraceCmpZeroExtAL, VoidTy,
412 IRB.getInt16Ty(), IRB.getInt16Ty());
413 SanCovTraceCmpFunction[2] =
414 M.getOrInsertFunction(SanCovTraceCmp4, SanCovTraceCmpZeroExtAL, VoidTy,
415 IRB.getInt32Ty(), IRB.getInt32Ty());
416 SanCovTraceCmpFunction[3] =
417 M.getOrInsertFunction(SanCovTraceCmp8, VoidTy, Int64Ty, Int64Ty);
418
419 SanCovTraceConstCmpFunction[0] = M.getOrInsertFunction(
420 SanCovTraceConstCmp1, SanCovTraceCmpZeroExtAL, VoidTy, Int8Ty, Int8Ty);
421 SanCovTraceConstCmpFunction[1] = M.getOrInsertFunction(
422 SanCovTraceConstCmp2, SanCovTraceCmpZeroExtAL, VoidTy, Int16Ty, Int16Ty);
423 SanCovTraceConstCmpFunction[2] = M.getOrInsertFunction(
424 SanCovTraceConstCmp4, SanCovTraceCmpZeroExtAL, VoidTy, Int32Ty, Int32Ty);
425 SanCovTraceConstCmpFunction[3] =
426 M.getOrInsertFunction(SanCovTraceConstCmp8, VoidTy, Int64Ty, Int64Ty);
427
428 // Loads.
429 SanCovLoadFunction[0] = M.getOrInsertFunction(SanCovLoad1, VoidTy, Int8PtrTy);
430 SanCovLoadFunction[1] =
431 M.getOrInsertFunction(SanCovLoad2, VoidTy, Int16PtrTy);
432 SanCovLoadFunction[2] =
433 M.getOrInsertFunction(SanCovLoad4, VoidTy, Int32PtrTy);
434 SanCovLoadFunction[3] =
435 M.getOrInsertFunction(SanCovLoad8, VoidTy, Int64PtrTy);
436 SanCovLoadFunction[4] =
437 M.getOrInsertFunction(SanCovLoad16, VoidTy, Int128PtrTy);
438 // Stores.
439 SanCovStoreFunction[0] =
440 M.getOrInsertFunction(SanCovStore1, VoidTy, Int8PtrTy);
441 SanCovStoreFunction[1] =
442 M.getOrInsertFunction(SanCovStore2, VoidTy, Int16PtrTy);
443 SanCovStoreFunction[2] =
444 M.getOrInsertFunction(SanCovStore4, VoidTy, Int32PtrTy);
445 SanCovStoreFunction[3] =
446 M.getOrInsertFunction(SanCovStore8, VoidTy, Int64PtrTy);
447 SanCovStoreFunction[4] =
448 M.getOrInsertFunction(SanCovStore16, VoidTy, Int128PtrTy);
449
450 {
451 AttributeList AL;
452 AL = AL.addParamAttribute(*C, 0, Attribute::ZExt);
453 SanCovTraceDivFunction[0] =
454 M.getOrInsertFunction(SanCovTraceDiv4, AL, VoidTy, IRB.getInt32Ty());
455 }
456 SanCovTraceDivFunction[1] =
457 M.getOrInsertFunction(SanCovTraceDiv8, VoidTy, Int64Ty);
458 SanCovTraceGepFunction =
459 M.getOrInsertFunction(SanCovTraceGep, VoidTy, IntptrTy);
460 SanCovTraceSwitchFunction =
461 M.getOrInsertFunction(SanCovTraceSwitchName, VoidTy, Int64Ty, Int64PtrTy);
462
463 Constant *SanCovLowestStackConstant =
464 M.getOrInsertGlobal(SanCovLowestStackName, IntptrTy);
465 SanCovLowestStack = dyn_cast<GlobalVariable>(SanCovLowestStackConstant);
466 if (!SanCovLowestStack || SanCovLowestStack->getValueType() != IntptrTy) {
467 C->emitError(StringRef("'") + SanCovLowestStackName +
468 "' should not be declared by the user");
469 return true;
470 }
471 SanCovLowestStack->setThreadLocalMode(
472 GlobalValue::ThreadLocalMode::InitialExecTLSModel);
473 if (Options.StackDepth && !SanCovLowestStack->isDeclaration())
474 SanCovLowestStack->setInitializer(Constant::getAllOnesValue(IntptrTy));
475
476 SanCovTracePC = M.getOrInsertFunction(SanCovTracePCName, VoidTy);
477 SanCovTracePCGuard =
478 M.getOrInsertFunction(SanCovTracePCGuardName, VoidTy, Int32PtrTy);
479
480 for (auto &F : M)
481 instrumentFunction(F, DTCallback, PDTCallback);
482
483 Function *Ctor = nullptr;
484
485 if (FunctionGuardArray)
486 Ctor = CreateInitCallsForSections(M, SanCovModuleCtorTracePcGuardName,
487 SanCovTracePCGuardInitName, Int32Ty,
488 SanCovGuardsSectionName);
489 if (Function8bitCounterArray)
490 Ctor = CreateInitCallsForSections(M, SanCovModuleCtor8bitCountersName,
491 SanCov8bitCountersInitName, Int8Ty,
492 SanCovCountersSectionName);
493 if (FunctionBoolArray) {
494 Ctor = CreateInitCallsForSections(M, SanCovModuleCtorBoolFlagName,
495 SanCovBoolFlagInitName, Int1Ty,
496 SanCovBoolFlagSectionName);
497 }
498 if (Ctor && Options.PCTable) {
499 auto SecStartEnd = CreateSecStartEnd(M, SanCovPCsSectionName, IntptrTy);
500 FunctionCallee InitFunction = declareSanitizerInitFunction(
501 M, SanCovPCsInitName, {IntptrPtrTy, IntptrPtrTy});
502 IRBuilder<> IRBCtor(Ctor->getEntryBlock().getTerminator());
503 IRBCtor.CreateCall(InitFunction, {SecStartEnd.first, SecStartEnd.second});
504 }
505 appendToUsed(M, GlobalsToAppendToUsed);
506 appendToCompilerUsed(M, GlobalsToAppendToCompilerUsed);
507 return true;
508 }
509
510 // True if block has successors and it dominates all of them.
isFullDominator(const BasicBlock * BB,const DominatorTree * DT)511 static bool isFullDominator(const BasicBlock *BB, const DominatorTree *DT) {
512 if (succ_empty(BB))
513 return false;
514
515 return llvm::all_of(successors(BB), [&](const BasicBlock *SUCC) {
516 return DT->dominates(BB, SUCC);
517 });
518 }
519
520 // True if block has predecessors and it postdominates all of them.
isFullPostDominator(const BasicBlock * BB,const PostDominatorTree * PDT)521 static bool isFullPostDominator(const BasicBlock *BB,
522 const PostDominatorTree *PDT) {
523 if (pred_empty(BB))
524 return false;
525
526 return llvm::all_of(predecessors(BB), [&](const BasicBlock *PRED) {
527 return PDT->dominates(BB, PRED);
528 });
529 }
530
shouldInstrumentBlock(const Function & F,const BasicBlock * BB,const DominatorTree * DT,const PostDominatorTree * PDT,const SanitizerCoverageOptions & Options)531 static bool shouldInstrumentBlock(const Function &F, const BasicBlock *BB,
532 const DominatorTree *DT,
533 const PostDominatorTree *PDT,
534 const SanitizerCoverageOptions &Options) {
535 // Don't insert coverage for blocks containing nothing but unreachable: we
536 // will never call __sanitizer_cov() for them, so counting them in
537 // NumberOfInstrumentedBlocks() might complicate calculation of code coverage
538 // percentage. Also, unreachable instructions frequently have no debug
539 // locations.
540 if (isa<UnreachableInst>(BB->getFirstNonPHIOrDbgOrLifetime()))
541 return false;
542
543 // Don't insert coverage into blocks without a valid insertion point
544 // (catchswitch blocks).
545 if (BB->getFirstInsertionPt() == BB->end())
546 return false;
547
548 if (Options.NoPrune || &F.getEntryBlock() == BB)
549 return true;
550
551 if (Options.CoverageType == SanitizerCoverageOptions::SCK_Function &&
552 &F.getEntryBlock() != BB)
553 return false;
554
555 // Do not instrument full dominators, or full post-dominators with multiple
556 // predecessors.
557 return !isFullDominator(BB, DT)
558 && !(isFullPostDominator(BB, PDT) && !BB->getSinglePredecessor());
559 }
560
561
562 // Returns true iff From->To is a backedge.
563 // A twist here is that we treat From->To as a backedge if
564 // * To dominates From or
565 // * To->UniqueSuccessor dominates From
IsBackEdge(BasicBlock * From,BasicBlock * To,const DominatorTree * DT)566 static bool IsBackEdge(BasicBlock *From, BasicBlock *To,
567 const DominatorTree *DT) {
568 if (DT->dominates(To, From))
569 return true;
570 if (auto Next = To->getUniqueSuccessor())
571 if (DT->dominates(Next, From))
572 return true;
573 return false;
574 }
575
576 // Prunes uninteresting Cmp instrumentation:
577 // * CMP instructions that feed into loop backedge branch.
578 //
579 // Note that Cmp pruning is controlled by the same flag as the
580 // BB pruning.
IsInterestingCmp(ICmpInst * CMP,const DominatorTree * DT,const SanitizerCoverageOptions & Options)581 static bool IsInterestingCmp(ICmpInst *CMP, const DominatorTree *DT,
582 const SanitizerCoverageOptions &Options) {
583 if (!Options.NoPrune)
584 if (CMP->hasOneUse())
585 if (auto BR = dyn_cast<BranchInst>(CMP->user_back()))
586 for (BasicBlock *B : BR->successors())
587 if (IsBackEdge(BR->getParent(), B, DT))
588 return false;
589 return true;
590 }
591
instrumentFunction(Function & F,DomTreeCallback DTCallback,PostDomTreeCallback PDTCallback)592 void ModuleSanitizerCoverage::instrumentFunction(
593 Function &F, DomTreeCallback DTCallback, PostDomTreeCallback PDTCallback) {
594 if (F.empty())
595 return;
596 if (F.getName().find(".module_ctor") != std::string::npos)
597 return; // Should not instrument sanitizer init functions.
598 if (F.getName().startswith("__sanitizer_"))
599 return; // Don't instrument __sanitizer_* callbacks.
600 // Don't touch available_externally functions, their actual body is elewhere.
601 if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage)
602 return;
603 // Don't instrument MSVC CRT configuration helpers. They may run before normal
604 // initialization.
605 if (F.getName() == "__local_stdio_printf_options" ||
606 F.getName() == "__local_stdio_scanf_options")
607 return;
608 if (isa<UnreachableInst>(F.getEntryBlock().getTerminator()))
609 return;
610 // Don't instrument functions using SEH for now. Splitting basic blocks like
611 // we do for coverage breaks WinEHPrepare.
612 // FIXME: Remove this when SEH no longer uses landingpad pattern matching.
613 if (F.hasPersonalityFn() &&
614 isAsynchronousEHPersonality(classifyEHPersonality(F.getPersonalityFn())))
615 return;
616 if (Allowlist && !Allowlist->inSection("coverage", "fun", F.getName()))
617 return;
618 if (Blocklist && Blocklist->inSection("coverage", "fun", F.getName()))
619 return;
620 if (F.hasFnAttribute(Attribute::NoSanitizeCoverage))
621 return;
622 if (Options.CoverageType >= SanitizerCoverageOptions::SCK_Edge)
623 SplitAllCriticalEdges(F, CriticalEdgeSplittingOptions().setIgnoreUnreachableDests());
624 SmallVector<Instruction *, 8> IndirCalls;
625 SmallVector<BasicBlock *, 16> BlocksToInstrument;
626 SmallVector<Instruction *, 8> CmpTraceTargets;
627 SmallVector<Instruction *, 8> SwitchTraceTargets;
628 SmallVector<BinaryOperator *, 8> DivTraceTargets;
629 SmallVector<GetElementPtrInst *, 8> GepTraceTargets;
630 SmallVector<LoadInst *, 8> Loads;
631 SmallVector<StoreInst *, 8> Stores;
632
633 const DominatorTree *DT = DTCallback(F);
634 const PostDominatorTree *PDT = PDTCallback(F);
635 bool IsLeafFunc = true;
636
637 for (auto &BB : F) {
638 if (shouldInstrumentBlock(F, &BB, DT, PDT, Options))
639 BlocksToInstrument.push_back(&BB);
640 for (auto &Inst : BB) {
641 if (Options.IndirectCalls) {
642 CallBase *CB = dyn_cast<CallBase>(&Inst);
643 if (CB && CB->isIndirectCall())
644 IndirCalls.push_back(&Inst);
645 }
646 if (Options.TraceCmp) {
647 if (ICmpInst *CMP = dyn_cast<ICmpInst>(&Inst))
648 if (IsInterestingCmp(CMP, DT, Options))
649 CmpTraceTargets.push_back(&Inst);
650 if (isa<SwitchInst>(&Inst))
651 SwitchTraceTargets.push_back(&Inst);
652 }
653 if (Options.TraceDiv)
654 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(&Inst))
655 if (BO->getOpcode() == Instruction::SDiv ||
656 BO->getOpcode() == Instruction::UDiv)
657 DivTraceTargets.push_back(BO);
658 if (Options.TraceGep)
659 if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(&Inst))
660 GepTraceTargets.push_back(GEP);
661 if (Options.TraceLoads)
662 if (LoadInst *LI = dyn_cast<LoadInst>(&Inst))
663 Loads.push_back(LI);
664 if (Options.TraceStores)
665 if (StoreInst *SI = dyn_cast<StoreInst>(&Inst))
666 Stores.push_back(SI);
667 if (Options.StackDepth)
668 if (isa<InvokeInst>(Inst) ||
669 (isa<CallInst>(Inst) && !isa<IntrinsicInst>(Inst)))
670 IsLeafFunc = false;
671 }
672 }
673
674 InjectCoverage(F, BlocksToInstrument, IsLeafFunc);
675 InjectCoverageForIndirectCalls(F, IndirCalls);
676 InjectTraceForCmp(F, CmpTraceTargets);
677 InjectTraceForSwitch(F, SwitchTraceTargets);
678 InjectTraceForDiv(F, DivTraceTargets);
679 InjectTraceForGep(F, GepTraceTargets);
680 InjectTraceForLoadsAndStores(F, Loads, Stores);
681 }
682
CreateFunctionLocalArrayInSection(size_t NumElements,Function & F,Type * Ty,const char * Section)683 GlobalVariable *ModuleSanitizerCoverage::CreateFunctionLocalArrayInSection(
684 size_t NumElements, Function &F, Type *Ty, const char *Section) {
685 ArrayType *ArrayTy = ArrayType::get(Ty, NumElements);
686 auto Array = new GlobalVariable(
687 *CurModule, ArrayTy, false, GlobalVariable::PrivateLinkage,
688 Constant::getNullValue(ArrayTy), "__sancov_gen_");
689
690 if (TargetTriple.supportsCOMDAT() &&
691 (TargetTriple.isOSBinFormatELF() || !F.isInterposable()))
692 if (auto Comdat = getOrCreateFunctionComdat(F, TargetTriple))
693 Array->setComdat(Comdat);
694 Array->setSection(getSectionName(Section));
695 Array->setAlignment(Align(DL->getTypeStoreSize(Ty).getFixedSize()));
696
697 // sancov_pcs parallels the other metadata section(s). Optimizers (e.g.
698 // GlobalOpt/ConstantMerge) may not discard sancov_pcs and the other
699 // section(s) as a unit, so we conservatively retain all unconditionally in
700 // the compiler.
701 //
702 // With comdat (COFF/ELF), the linker can guarantee the associated sections
703 // will be retained or discarded as a unit, so llvm.compiler.used is
704 // sufficient. Otherwise, conservatively make all of them retained by the
705 // linker.
706 if (Array->hasComdat())
707 GlobalsToAppendToCompilerUsed.push_back(Array);
708 else
709 GlobalsToAppendToUsed.push_back(Array);
710
711 return Array;
712 }
713
714 GlobalVariable *
CreatePCArray(Function & F,ArrayRef<BasicBlock * > AllBlocks)715 ModuleSanitizerCoverage::CreatePCArray(Function &F,
716 ArrayRef<BasicBlock *> AllBlocks) {
717 size_t N = AllBlocks.size();
718 assert(N);
719 SmallVector<Constant *, 32> PCs;
720 IRBuilder<> IRB(&*F.getEntryBlock().getFirstInsertionPt());
721 for (size_t i = 0; i < N; i++) {
722 if (&F.getEntryBlock() == AllBlocks[i]) {
723 PCs.push_back((Constant *)IRB.CreatePointerCast(&F, IntptrPtrTy));
724 PCs.push_back((Constant *)IRB.CreateIntToPtr(
725 ConstantInt::get(IntptrTy, 1), IntptrPtrTy));
726 } else {
727 PCs.push_back((Constant *)IRB.CreatePointerCast(
728 BlockAddress::get(AllBlocks[i]), IntptrPtrTy));
729 PCs.push_back((Constant *)IRB.CreateIntToPtr(
730 ConstantInt::get(IntptrTy, 0), IntptrPtrTy));
731 }
732 }
733 auto *PCArray = CreateFunctionLocalArrayInSection(N * 2, F, IntptrPtrTy,
734 SanCovPCsSectionName);
735 PCArray->setInitializer(
736 ConstantArray::get(ArrayType::get(IntptrPtrTy, N * 2), PCs));
737 PCArray->setConstant(true);
738
739 return PCArray;
740 }
741
CreateFunctionLocalArrays(Function & F,ArrayRef<BasicBlock * > AllBlocks)742 void ModuleSanitizerCoverage::CreateFunctionLocalArrays(
743 Function &F, ArrayRef<BasicBlock *> AllBlocks) {
744 if (Options.TracePCGuard)
745 FunctionGuardArray = CreateFunctionLocalArrayInSection(
746 AllBlocks.size(), F, Int32Ty, SanCovGuardsSectionName);
747
748 if (Options.Inline8bitCounters)
749 Function8bitCounterArray = CreateFunctionLocalArrayInSection(
750 AllBlocks.size(), F, Int8Ty, SanCovCountersSectionName);
751 if (Options.InlineBoolFlag)
752 FunctionBoolArray = CreateFunctionLocalArrayInSection(
753 AllBlocks.size(), F, Int1Ty, SanCovBoolFlagSectionName);
754
755 if (Options.PCTable)
756 FunctionPCsArray = CreatePCArray(F, AllBlocks);
757 }
758
InjectCoverage(Function & F,ArrayRef<BasicBlock * > AllBlocks,bool IsLeafFunc)759 bool ModuleSanitizerCoverage::InjectCoverage(Function &F,
760 ArrayRef<BasicBlock *> AllBlocks,
761 bool IsLeafFunc) {
762 if (AllBlocks.empty()) return false;
763 CreateFunctionLocalArrays(F, AllBlocks);
764 for (size_t i = 0, N = AllBlocks.size(); i < N; i++)
765 InjectCoverageAtBlock(F, *AllBlocks[i], i, IsLeafFunc);
766 return true;
767 }
768
769 // On every indirect call we call a run-time function
770 // __sanitizer_cov_indir_call* with two parameters:
771 // - callee address,
772 // - global cache array that contains CacheSize pointers (zero-initialized).
773 // The cache is used to speed up recording the caller-callee pairs.
774 // The address of the caller is passed implicitly via caller PC.
775 // CacheSize is encoded in the name of the run-time function.
InjectCoverageForIndirectCalls(Function & F,ArrayRef<Instruction * > IndirCalls)776 void ModuleSanitizerCoverage::InjectCoverageForIndirectCalls(
777 Function &F, ArrayRef<Instruction *> IndirCalls) {
778 if (IndirCalls.empty())
779 return;
780 assert(Options.TracePC || Options.TracePCGuard ||
781 Options.Inline8bitCounters || Options.InlineBoolFlag);
782 for (auto I : IndirCalls) {
783 IRBuilder<> IRB(I);
784 CallBase &CB = cast<CallBase>(*I);
785 Value *Callee = CB.getCalledOperand();
786 if (isa<InlineAsm>(Callee))
787 continue;
788 IRB.CreateCall(SanCovTracePCIndir, IRB.CreatePointerCast(Callee, IntptrTy));
789 }
790 }
791
792 // For every switch statement we insert a call:
793 // __sanitizer_cov_trace_switch(CondValue,
794 // {NumCases, ValueSizeInBits, Case0Value, Case1Value, Case2Value, ... })
795
InjectTraceForSwitch(Function &,ArrayRef<Instruction * > SwitchTraceTargets)796 void ModuleSanitizerCoverage::InjectTraceForSwitch(
797 Function &, ArrayRef<Instruction *> SwitchTraceTargets) {
798 for (auto I : SwitchTraceTargets) {
799 if (SwitchInst *SI = dyn_cast<SwitchInst>(I)) {
800 IRBuilder<> IRB(I);
801 SmallVector<Constant *, 16> Initializers;
802 Value *Cond = SI->getCondition();
803 if (Cond->getType()->getScalarSizeInBits() >
804 Int64Ty->getScalarSizeInBits())
805 continue;
806 Initializers.push_back(ConstantInt::get(Int64Ty, SI->getNumCases()));
807 Initializers.push_back(
808 ConstantInt::get(Int64Ty, Cond->getType()->getScalarSizeInBits()));
809 if (Cond->getType()->getScalarSizeInBits() <
810 Int64Ty->getScalarSizeInBits())
811 Cond = IRB.CreateIntCast(Cond, Int64Ty, false);
812 for (auto It : SI->cases()) {
813 Constant *C = It.getCaseValue();
814 if (C->getType()->getScalarSizeInBits() <
815 Int64Ty->getScalarSizeInBits())
816 C = ConstantExpr::getCast(CastInst::ZExt, It.getCaseValue(), Int64Ty);
817 Initializers.push_back(C);
818 }
819 llvm::sort(drop_begin(Initializers, 2),
820 [](const Constant *A, const Constant *B) {
821 return cast<ConstantInt>(A)->getLimitedValue() <
822 cast<ConstantInt>(B)->getLimitedValue();
823 });
824 ArrayType *ArrayOfInt64Ty = ArrayType::get(Int64Ty, Initializers.size());
825 GlobalVariable *GV = new GlobalVariable(
826 *CurModule, ArrayOfInt64Ty, false, GlobalVariable::InternalLinkage,
827 ConstantArray::get(ArrayOfInt64Ty, Initializers),
828 "__sancov_gen_cov_switch_values");
829 IRB.CreateCall(SanCovTraceSwitchFunction,
830 {Cond, IRB.CreatePointerCast(GV, Int64PtrTy)});
831 }
832 }
833 }
834
InjectTraceForDiv(Function &,ArrayRef<BinaryOperator * > DivTraceTargets)835 void ModuleSanitizerCoverage::InjectTraceForDiv(
836 Function &, ArrayRef<BinaryOperator *> DivTraceTargets) {
837 for (auto BO : DivTraceTargets) {
838 IRBuilder<> IRB(BO);
839 Value *A1 = BO->getOperand(1);
840 if (isa<ConstantInt>(A1)) continue;
841 if (!A1->getType()->isIntegerTy())
842 continue;
843 uint64_t TypeSize = DL->getTypeStoreSizeInBits(A1->getType());
844 int CallbackIdx = TypeSize == 32 ? 0 :
845 TypeSize == 64 ? 1 : -1;
846 if (CallbackIdx < 0) continue;
847 auto Ty = Type::getIntNTy(*C, TypeSize);
848 IRB.CreateCall(SanCovTraceDivFunction[CallbackIdx],
849 {IRB.CreateIntCast(A1, Ty, true)});
850 }
851 }
852
InjectTraceForGep(Function &,ArrayRef<GetElementPtrInst * > GepTraceTargets)853 void ModuleSanitizerCoverage::InjectTraceForGep(
854 Function &, ArrayRef<GetElementPtrInst *> GepTraceTargets) {
855 for (auto GEP : GepTraceTargets) {
856 IRBuilder<> IRB(GEP);
857 for (Use &Idx : GEP->indices())
858 if (!isa<ConstantInt>(Idx) && Idx->getType()->isIntegerTy())
859 IRB.CreateCall(SanCovTraceGepFunction,
860 {IRB.CreateIntCast(Idx, IntptrTy, true)});
861 }
862 }
863
InjectTraceForLoadsAndStores(Function &,ArrayRef<LoadInst * > Loads,ArrayRef<StoreInst * > Stores)864 void ModuleSanitizerCoverage::InjectTraceForLoadsAndStores(
865 Function &, ArrayRef<LoadInst *> Loads, ArrayRef<StoreInst *> Stores) {
866 auto CallbackIdx = [&](Type *ElementTy) -> int {
867 uint64_t TypeSize = DL->getTypeStoreSizeInBits(ElementTy);
868 return TypeSize == 8 ? 0
869 : TypeSize == 16 ? 1
870 : TypeSize == 32 ? 2
871 : TypeSize == 64 ? 3
872 : TypeSize == 128 ? 4
873 : -1;
874 };
875 Type *PointerType[5] = {Int8PtrTy, Int16PtrTy, Int32PtrTy, Int64PtrTy,
876 Int128PtrTy};
877 for (auto LI : Loads) {
878 IRBuilder<> IRB(LI);
879 auto Ptr = LI->getPointerOperand();
880 int Idx = CallbackIdx(LI->getType());
881 if (Idx < 0)
882 continue;
883 IRB.CreateCall(SanCovLoadFunction[Idx],
884 IRB.CreatePointerCast(Ptr, PointerType[Idx]));
885 }
886 for (auto SI : Stores) {
887 IRBuilder<> IRB(SI);
888 auto Ptr = SI->getPointerOperand();
889 int Idx = CallbackIdx(SI->getValueOperand()->getType());
890 if (Idx < 0)
891 continue;
892 IRB.CreateCall(SanCovStoreFunction[Idx],
893 IRB.CreatePointerCast(Ptr, PointerType[Idx]));
894 }
895 }
896
InjectTraceForCmp(Function &,ArrayRef<Instruction * > CmpTraceTargets)897 void ModuleSanitizerCoverage::InjectTraceForCmp(
898 Function &, ArrayRef<Instruction *> CmpTraceTargets) {
899 for (auto I : CmpTraceTargets) {
900 if (ICmpInst *ICMP = dyn_cast<ICmpInst>(I)) {
901 IRBuilder<> IRB(ICMP);
902 Value *A0 = ICMP->getOperand(0);
903 Value *A1 = ICMP->getOperand(1);
904 if (!A0->getType()->isIntegerTy())
905 continue;
906 uint64_t TypeSize = DL->getTypeStoreSizeInBits(A0->getType());
907 int CallbackIdx = TypeSize == 8 ? 0 :
908 TypeSize == 16 ? 1 :
909 TypeSize == 32 ? 2 :
910 TypeSize == 64 ? 3 : -1;
911 if (CallbackIdx < 0) continue;
912 // __sanitizer_cov_trace_cmp((type_size << 32) | predicate, A0, A1);
913 auto CallbackFunc = SanCovTraceCmpFunction[CallbackIdx];
914 bool FirstIsConst = isa<ConstantInt>(A0);
915 bool SecondIsConst = isa<ConstantInt>(A1);
916 // If both are const, then we don't need such a comparison.
917 if (FirstIsConst && SecondIsConst) continue;
918 // If only one is const, then make it the first callback argument.
919 if (FirstIsConst || SecondIsConst) {
920 CallbackFunc = SanCovTraceConstCmpFunction[CallbackIdx];
921 if (SecondIsConst)
922 std::swap(A0, A1);
923 }
924
925 auto Ty = Type::getIntNTy(*C, TypeSize);
926 IRB.CreateCall(CallbackFunc, {IRB.CreateIntCast(A0, Ty, true),
927 IRB.CreateIntCast(A1, Ty, true)});
928 }
929 }
930 }
931
InjectCoverageAtBlock(Function & F,BasicBlock & BB,size_t Idx,bool IsLeafFunc)932 void ModuleSanitizerCoverage::InjectCoverageAtBlock(Function &F, BasicBlock &BB,
933 size_t Idx,
934 bool IsLeafFunc) {
935 BasicBlock::iterator IP = BB.getFirstInsertionPt();
936 bool IsEntryBB = &BB == &F.getEntryBlock();
937 DebugLoc EntryLoc;
938 if (IsEntryBB) {
939 if (auto SP = F.getSubprogram())
940 EntryLoc = DILocation::get(SP->getContext(), SP->getScopeLine(), 0, SP);
941 // Keep static allocas and llvm.localescape calls in the entry block. Even
942 // if we aren't splitting the block, it's nice for allocas to be before
943 // calls.
944 IP = PrepareToSplitEntryBlock(BB, IP);
945 }
946
947 InstrumentationIRBuilder IRB(&*IP);
948 if (EntryLoc)
949 IRB.SetCurrentDebugLocation(EntryLoc);
950 if (Options.TracePC) {
951 IRB.CreateCall(SanCovTracePC)
952 ->setCannotMerge(); // gets the PC using GET_CALLER_PC.
953 }
954 if (Options.TracePCGuard) {
955 auto GuardPtr = IRB.CreateIntToPtr(
956 IRB.CreateAdd(IRB.CreatePointerCast(FunctionGuardArray, IntptrTy),
957 ConstantInt::get(IntptrTy, Idx * 4)),
958 Int32PtrTy);
959 IRB.CreateCall(SanCovTracePCGuard, GuardPtr)->setCannotMerge();
960 }
961 if (Options.Inline8bitCounters) {
962 auto CounterPtr = IRB.CreateGEP(
963 Function8bitCounterArray->getValueType(), Function8bitCounterArray,
964 {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)});
965 auto Load = IRB.CreateLoad(Int8Ty, CounterPtr);
966 auto Inc = IRB.CreateAdd(Load, ConstantInt::get(Int8Ty, 1));
967 auto Store = IRB.CreateStore(Inc, CounterPtr);
968 SetNoSanitizeMetadata(Load);
969 SetNoSanitizeMetadata(Store);
970 }
971 if (Options.InlineBoolFlag) {
972 auto FlagPtr = IRB.CreateGEP(
973 FunctionBoolArray->getValueType(), FunctionBoolArray,
974 {ConstantInt::get(IntptrTy, 0), ConstantInt::get(IntptrTy, Idx)});
975 auto Load = IRB.CreateLoad(Int1Ty, FlagPtr);
976 auto ThenTerm =
977 SplitBlockAndInsertIfThen(IRB.CreateIsNull(Load), &*IP, false);
978 IRBuilder<> ThenIRB(ThenTerm);
979 auto Store = ThenIRB.CreateStore(ConstantInt::getTrue(Int1Ty), FlagPtr);
980 SetNoSanitizeMetadata(Load);
981 SetNoSanitizeMetadata(Store);
982 }
983 if (Options.StackDepth && IsEntryBB && !IsLeafFunc) {
984 // Check stack depth. If it's the deepest so far, record it.
985 Module *M = F.getParent();
986 Function *GetFrameAddr = Intrinsic::getDeclaration(
987 M, Intrinsic::frameaddress,
988 IRB.getInt8PtrTy(M->getDataLayout().getAllocaAddrSpace()));
989 auto FrameAddrPtr =
990 IRB.CreateCall(GetFrameAddr, {Constant::getNullValue(Int32Ty)});
991 auto FrameAddrInt = IRB.CreatePtrToInt(FrameAddrPtr, IntptrTy);
992 auto LowestStack = IRB.CreateLoad(IntptrTy, SanCovLowestStack);
993 auto IsStackLower = IRB.CreateICmpULT(FrameAddrInt, LowestStack);
994 auto ThenTerm = SplitBlockAndInsertIfThen(IsStackLower, &*IP, false);
995 IRBuilder<> ThenIRB(ThenTerm);
996 auto Store = ThenIRB.CreateStore(FrameAddrInt, SanCovLowestStack);
997 SetNoSanitizeMetadata(LowestStack);
998 SetNoSanitizeMetadata(Store);
999 }
1000 }
1001
1002 std::string
getSectionName(const std::string & Section) const1003 ModuleSanitizerCoverage::getSectionName(const std::string &Section) const {
1004 if (TargetTriple.isOSBinFormatCOFF()) {
1005 if (Section == SanCovCountersSectionName)
1006 return ".SCOV$CM";
1007 if (Section == SanCovBoolFlagSectionName)
1008 return ".SCOV$BM";
1009 if (Section == SanCovPCsSectionName)
1010 return ".SCOVP$M";
1011 return ".SCOV$GM"; // For SanCovGuardsSectionName.
1012 }
1013 if (TargetTriple.isOSBinFormatMachO())
1014 return "__DATA,__" + Section;
1015 return "__" + Section;
1016 }
1017
1018 std::string
getSectionStart(const std::string & Section) const1019 ModuleSanitizerCoverage::getSectionStart(const std::string &Section) const {
1020 if (TargetTriple.isOSBinFormatMachO())
1021 return "\1section$start$__DATA$__" + Section;
1022 return "__start___" + Section;
1023 }
1024
1025 std::string
getSectionEnd(const std::string & Section) const1026 ModuleSanitizerCoverage::getSectionEnd(const std::string &Section) const {
1027 if (TargetTriple.isOSBinFormatMachO())
1028 return "\1section$end$__DATA$__" + Section;
1029 return "__stop___" + Section;
1030 }
1031