1//===-- SanitizerCoverage.cpp - coverage instrumentation for sanitizers ---===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// Coverage instrumentation done on LLVM IR level, works with Sanitizers.
10//
11//===----------------------------------------------------------------------===//
12
13#include "llvm/Transforms/Instrumentation/SanitizerCoverage.h"
14#include "llvm/ADT/ArrayRef.h"
15#include "llvm/ADT/SmallVector.h"
16#include "llvm/Analysis/GlobalsModRef.h"
17#include "llvm/Analysis/PostDominators.h"
18#include "llvm/IR/Constant.h"
19#include "llvm/IR/DataLayout.h"
20#include "llvm/IR/Dominators.h"
21#include "llvm/IR/EHPersonalities.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/MDBuilder.h"
29#include "llvm/IR/Module.h"
30#include "llvm/IR/Type.h"
31#include "llvm/Support/CommandLine.h"
32#include "llvm/Support/SpecialCaseList.h"
33#include "llvm/Support/VirtualFileSystem.h"
34#include "llvm/TargetParser/Triple.h"
35#include "llvm/Transforms/Utils/BasicBlockUtils.h"
36#include "llvm/Transforms/Utils/ModuleUtils.h"
37
38using namespace llvm;
39
40#define DEBUG_TYPE "sancov"
41
42const char SanCovTracePCIndirName[] = "__sanitizer_cov_trace_pc_indir";
43const char SanCovTracePCName[] = "__sanitizer_cov_trace_pc";
44const char SanCovTraceCmp1[] = "__sanitizer_cov_trace_cmp1";
45const char SanCovTraceCmp2[] = "__sanitizer_cov_trace_cmp2";
46const char SanCovTraceCmp4[] = "__sanitizer_cov_trace_cmp4";
47const char SanCovTraceCmp8[] = "__sanitizer_cov_trace_cmp8";
48const char SanCovTraceConstCmp1[] = "__sanitizer_cov_trace_const_cmp1";
49const char SanCovTraceConstCmp2[] = "__sanitizer_cov_trace_const_cmp2";
50const char SanCovTraceConstCmp4[] = "__sanitizer_cov_trace_const_cmp4";
51const char SanCovTraceConstCmp8[] = "__sanitizer_cov_trace_const_cmp8";
52const char SanCovLoad1[] = "__sanitizer_cov_load1";
53const char SanCovLoad2[] = "__sanitizer_cov_load2";
54const char SanCovLoad4[] = "__sanitizer_cov_load4";
55const char SanCovLoad8[] = "__sanitizer_cov_load8";
56const char SanCovLoad16[] = "__sanitizer_cov_load16";
57const char SanCovStore1[] = "__sanitizer_cov_store1";
58const char SanCovStore2[] = "__sanitizer_cov_store2";
59const char SanCovStore4[] = "__sanitizer_cov_store4";
60const char SanCovStore8[] = "__sanitizer_cov_store8";
61const char SanCovStore16[] = "__sanitizer_cov_store16";
62const char SanCovTraceDiv4[] = "__sanitizer_cov_trace_div4";
63const char SanCovTraceDiv8[] = "__sanitizer_cov_trace_div8";
64const char SanCovTraceGep[] = "__sanitizer_cov_trace_gep";
65const char SanCovTraceSwitchName[] = "__sanitizer_cov_trace_switch";
66const char SanCovModuleCtorTracePcGuardName[] =
67 "sancov.module_ctor_trace_pc_guard";
68const char SanCovModuleCtor8bitCountersName[] =
69 "sancov.module_ctor_8bit_counters";
70const char SanCovModuleCtorBoolFlagName[] = "sancov.module_ctor_bool_flag";
71static const uint64_t SanCtorAndDtorPriority = 2;
72
73const char SanCovTracePCGuardName[] = "__sanitizer_cov_trace_pc_guard";
74const char SanCovTracePCGuardInitName[] = "__sanitizer_cov_trace_pc_guard_init";
75const char SanCov8bitCountersInitName[] = "__sanitizer_cov_8bit_counters_init";
76const char SanCovBoolFlagInitName[] = "__sanitizer_cov_bool_flag_init";
77const char SanCovPCsInitName[] = "__sanitizer_cov_pcs_init";
78const char SanCovCFsInitName[] = "__sanitizer_cov_cfs_init";
79
80const char SanCovGuardsSectionName[] = "sancov_guards";
81const char SanCovCountersSectionName[] = "sancov_cntrs";
82const char SanCovBoolFlagSectionName[] = "sancov_bools";
83const char SanCovPCsSectionName[] = "sancov_pcs";
84const char SanCovCFsSectionName[] = "sancov_cfs";
85
86const char SanCovLowestStackName[] = "__sancov_lowest_stack";
87
88static cl::opt<int> ClCoverageLevel(
89 "sanitizer-coverage-level",
90 cl::desc("Sanitizer Coverage. 0: none, 1: entry block, 2: all blocks, "
91 "3: all blocks and critical edges"),
92 cl::Hidden);
93
94static cl::opt<bool> ClTracePC("sanitizer-coverage-trace-pc",
95 cl::desc("Experimental pc tracing"), cl::Hidden);
96
97static cl::opt<bool> ClTracePCGuard("sanitizer-coverage-trace-pc-guard",
98 cl::desc("pc tracing with a guard"),
99 cl::Hidden);
100
101// If true, we create a global variable that contains PCs of all instrumented
102// BBs, put this global into a named section, and pass this section's bounds
103// to __sanitizer_cov_pcs_init.
104// This way the coverage instrumentation does not need to acquire the PCs
105// at run-time. Works with trace-pc-guard, inline-8bit-counters, and
106// inline-bool-flag.
107static cl::opt<bool> ClCreatePCTable("sanitizer-coverage-pc-table",
108 cl::desc("create a static PC table"),
109 cl::Hidden);
110
111static cl::opt<bool>
112 ClInline8bitCounters("sanitizer-coverage-inline-8bit-counters",
113 cl::desc("increments 8-bit counter for every edge"),
114 cl::Hidden);
115
116static cl::opt<bool>
117 ClInlineBoolFlag("sanitizer-coverage-inline-bool-flag",
118 cl::desc("sets a boolean flag for every edge"),
119 cl::Hidden);
120
121static cl::opt<bool>
122 ClCMPTracing("sanitizer-coverage-trace-compares",
123 cl::desc("Tracing of CMP and similar instructions"),
124 cl::Hidden);
125
126static cl::opt<bool> ClDIVTracing("sanitizer-coverage-trace-divs",
127 cl::desc("Tracing of DIV instructions"),
128 cl::Hidden);
129
130static cl::opt<bool> ClLoadTracing("sanitizer-coverage-trace-loads",
131 cl::desc("Tracing of load instructions"),
132 cl::Hidden);
133
134static cl::opt<bool> ClStoreTracing("sanitizer-coverage-trace-stores",
135 cl::desc("Tracing of store instructions"),
136 cl::Hidden);
137
138static cl::opt<bool> ClGEPTracing("sanitizer-coverage-trace-geps",
139 cl::desc("Tracing of GEP instructions"),
140 cl::Hidden);
141
142static cl::opt<bool>
143 ClPruneBlocks("sanitizer-coverage-prune-blocks",
144 cl::desc("Reduce the number of instrumented blocks"),
145 cl::Hidden, cl::init(Val: true));
146
147static cl::opt<bool> ClStackDepth("sanitizer-coverage-stack-depth",
148 cl::desc("max stack depth tracing"),
149 cl::Hidden);
150
151static cl::opt<bool>
152 ClCollectCF("sanitizer-coverage-control-flow",
153 cl::desc("collect control flow for each function"), cl::Hidden);
154
155namespace {
156
157SanitizerCoverageOptions getOptions(int LegacyCoverageLevel) {
158 SanitizerCoverageOptions Res;
159 switch (LegacyCoverageLevel) {
160 case 0:
161 Res.CoverageType = SanitizerCoverageOptions::SCK_None;
162 break;
163 case 1:
164 Res.CoverageType = SanitizerCoverageOptions::SCK_Function;
165 break;
166 case 2:
167 Res.CoverageType = SanitizerCoverageOptions::SCK_BB;
168 break;
169 case 3:
170 Res.CoverageType = SanitizerCoverageOptions::SCK_Edge;
171 break;
172 case 4:
173 Res.CoverageType = SanitizerCoverageOptions::SCK_Edge;
174 Res.IndirectCalls = true;
175 break;
176 }
177 return Res;
178}
179
180SanitizerCoverageOptions OverrideFromCL(SanitizerCoverageOptions Options) {
181 // Sets CoverageType and IndirectCalls.
182 SanitizerCoverageOptions CLOpts = getOptions(LegacyCoverageLevel: ClCoverageLevel);
183 Options.CoverageType = std::max(a: Options.CoverageType, b: CLOpts.CoverageType);
184 Options.IndirectCalls |= CLOpts.IndirectCalls;
185 Options.TraceCmp |= ClCMPTracing;
186 Options.TraceDiv |= ClDIVTracing;
187 Options.TraceGep |= ClGEPTracing;
188 Options.TracePC |= ClTracePC;
189 Options.TracePCGuard |= ClTracePCGuard;
190 Options.Inline8bitCounters |= ClInline8bitCounters;
191 Options.InlineBoolFlag |= ClInlineBoolFlag;
192 Options.PCTable |= ClCreatePCTable;
193 Options.NoPrune |= !ClPruneBlocks;
194 Options.StackDepth |= ClStackDepth;
195 Options.TraceLoads |= ClLoadTracing;
196 Options.TraceStores |= ClStoreTracing;
197 if (!Options.TracePCGuard && !Options.TracePC &&
198 !Options.Inline8bitCounters && !Options.StackDepth &&
199 !Options.InlineBoolFlag && !Options.TraceLoads && !Options.TraceStores)
200 Options.TracePCGuard = true; // TracePCGuard is default.
201 Options.CollectControlFlow |= ClCollectCF;
202 return Options;
203}
204
205class ModuleSanitizerCoverage {
206public:
207 using DomTreeCallback = function_ref<const DominatorTree &(Function &F)>;
208 using PostDomTreeCallback =
209 function_ref<const PostDominatorTree &(Function &F)>;
210
211 ModuleSanitizerCoverage(Module &M, DomTreeCallback DTCallback,
212 PostDomTreeCallback PDTCallback,
213 const SanitizerCoverageOptions &Options,
214 const SpecialCaseList *Allowlist,
215 const SpecialCaseList *Blocklist)
216 : M(M), DTCallback(DTCallback), PDTCallback(PDTCallback),
217 Options(Options), Allowlist(Allowlist), Blocklist(Blocklist) {}
218
219 bool instrumentModule();
220
221private:
222 void createFunctionControlFlow(Function &F);
223 void instrumentFunction(Function &F);
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 std::string getSectionName(const std::string &Section) const;
251 std::string getSectionStart(const std::string &Section) const;
252 std::string getSectionEnd(const std::string &Section) const;
253
254 Module &M;
255 DomTreeCallback DTCallback;
256 PostDomTreeCallback PDTCallback;
257
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 *PtrTy, *IntptrTy, *Int64Ty, *Int32Ty, *Int16Ty, *Int8Ty, *Int1Ty;
269 Module *CurModule;
270 std::string CurModuleUniqueId;
271 Triple TargetTriple;
272 LLVMContext *C;
273 const DataLayout *DL;
274
275 GlobalVariable *FunctionGuardArray; // for trace-pc-guard.
276 GlobalVariable *Function8bitCounterArray; // for inline-8bit-counters.
277 GlobalVariable *FunctionBoolArray; // for inline-bool-flag.
278 GlobalVariable *FunctionPCsArray; // for pc-table.
279 GlobalVariable *FunctionCFsArray; // for control flow table
280 SmallVector<GlobalValue *, 20> GlobalsToAppendToUsed;
281 SmallVector<GlobalValue *, 20> GlobalsToAppendToCompilerUsed;
282
283 SanitizerCoverageOptions Options;
284
285 const SpecialCaseList *Allowlist;
286 const SpecialCaseList *Blocklist;
287};
288} // namespace
289
290PreservedAnalyses SanitizerCoveragePass::run(Module &M,
291 ModuleAnalysisManager &MAM) {
292 auto &FAM = MAM.getResult<FunctionAnalysisManagerModuleProxy>(IR&: M).getManager();
293 auto DTCallback = [&FAM](Function &F) -> const DominatorTree & {
294 return FAM.getResult<DominatorTreeAnalysis>(IR&: F);
295 };
296 auto PDTCallback = [&FAM](Function &F) -> const PostDominatorTree & {
297 return FAM.getResult<PostDominatorTreeAnalysis>(IR&: F);
298 };
299 ModuleSanitizerCoverage ModuleSancov(M, DTCallback, PDTCallback,
300 OverrideFromCL(Options), Allowlist.get(),
301 Blocklist.get());
302 if (!ModuleSancov.instrumentModule())
303 return PreservedAnalyses::all();
304
305 PreservedAnalyses PA = PreservedAnalyses::none();
306 // GlobalsAA is considered stateless and does not get invalidated unless
307 // explicitly invalidated; PreservedAnalyses::none() is not enough. Sanitizers
308 // make changes that require GlobalsAA to be invalidated.
309 PA.abandon<GlobalsAA>();
310 return PA;
311}
312
313std::pair<Value *, Value *>
314ModuleSanitizerCoverage::CreateSecStartEnd(Module &M, const char *Section,
315 Type *Ty) {
316 // Use ExternalWeak so that if all sections are discarded due to section
317 // garbage collection, the linker will not report undefined symbol errors.
318 // Windows defines the start/stop symbols in compiler-rt so no need for
319 // ExternalWeak.
320 GlobalValue::LinkageTypes Linkage = TargetTriple.isOSBinFormatCOFF()
321 ? GlobalVariable::ExternalLinkage
322 : GlobalVariable::ExternalWeakLinkage;
323 GlobalVariable *SecStart =
324 new GlobalVariable(M, Ty, false, Linkage, nullptr,
325 getSectionStart(Section));
326 SecStart->setVisibility(GlobalValue::HiddenVisibility);
327 GlobalVariable *SecEnd =
328 new GlobalVariable(M, Ty, false, Linkage, nullptr,
329 getSectionEnd(Section));
330 SecEnd->setVisibility(GlobalValue::HiddenVisibility);
331 IRBuilder<> IRB(M.getContext());
332 if (!TargetTriple.isOSBinFormatCOFF())
333 return std::make_pair(x&: SecStart, y&: SecEnd);
334
335 // Account for the fact that on windows-msvc __start_* symbols actually
336 // point to a uint64_t before the start of the array.
337 auto GEP =
338 IRB.CreatePtrAdd(Ptr: SecStart, Offset: ConstantInt::get(Ty: IntptrTy, V: sizeof(uint64_t)));
339 return std::make_pair(x&: GEP, y&: SecEnd);
340}
341
342Function *ModuleSanitizerCoverage::CreateInitCallsForSections(
343 Module &M, const char *CtorName, const char *InitFunctionName, Type *Ty,
344 const char *Section) {
345 auto SecStartEnd = CreateSecStartEnd(M, Section, Ty);
346 auto SecStart = SecStartEnd.first;
347 auto SecEnd = SecStartEnd.second;
348 Function *CtorFunc;
349 std::tie(args&: CtorFunc, args: std::ignore) = createSanitizerCtorAndInitFunctions(
350 M, CtorName, InitName: InitFunctionName, InitArgTypes: {PtrTy, PtrTy}, InitArgs: {SecStart, SecEnd});
351 assert(CtorFunc->getName() == CtorName);
352
353 if (TargetTriple.supportsCOMDAT()) {
354 // Use comdat to dedup CtorFunc.
355 CtorFunc->setComdat(M.getOrInsertComdat(Name: CtorName));
356 appendToGlobalCtors(M, F: CtorFunc, Priority: SanCtorAndDtorPriority, Data: CtorFunc);
357 } else {
358 appendToGlobalCtors(M, F: CtorFunc, Priority: SanCtorAndDtorPriority);
359 }
360
361 if (TargetTriple.isOSBinFormatCOFF()) {
362 // In COFF files, if the contructors are set as COMDAT (they are because
363 // COFF supports COMDAT) and the linker flag /OPT:REF (strip unreferenced
364 // functions and data) is used, the constructors get stripped. To prevent
365 // this, give the constructors weak ODR linkage and ensure the linker knows
366 // to include the sancov constructor. This way the linker can deduplicate
367 // the constructors but always leave one copy.
368 CtorFunc->setLinkage(GlobalValue::WeakODRLinkage);
369 }
370 return CtorFunc;
371}
372
373bool ModuleSanitizerCoverage::instrumentModule() {
374 if (Options.CoverageType == SanitizerCoverageOptions::SCK_None)
375 return false;
376 if (Allowlist &&
377 !Allowlist->inSection(Section: "coverage", Prefix: "src", Query: M.getSourceFileName()))
378 return false;
379 if (Blocklist &&
380 Blocklist->inSection(Section: "coverage", Prefix: "src", Query: M.getSourceFileName()))
381 return false;
382 C = &(M.getContext());
383 DL = &M.getDataLayout();
384 CurModule = &M;
385 CurModuleUniqueId = getUniqueModuleId(M: CurModule);
386 TargetTriple = Triple(M.getTargetTriple());
387 FunctionGuardArray = nullptr;
388 Function8bitCounterArray = nullptr;
389 FunctionBoolArray = nullptr;
390 FunctionPCsArray = nullptr;
391 FunctionCFsArray = nullptr;
392 IntptrTy = Type::getIntNTy(C&: *C, N: DL->getPointerSizeInBits());
393 PtrTy = PointerType::getUnqual(C&: *C);
394 Type *VoidTy = Type::getVoidTy(C&: *C);
395 IRBuilder<> IRB(*C);
396 Int64Ty = IRB.getInt64Ty();
397 Int32Ty = IRB.getInt32Ty();
398 Int16Ty = IRB.getInt16Ty();
399 Int8Ty = IRB.getInt8Ty();
400 Int1Ty = IRB.getInt1Ty();
401
402 SanCovTracePCIndir =
403 M.getOrInsertFunction(Name: SanCovTracePCIndirName, RetTy: VoidTy, Args: IntptrTy);
404 // Make sure smaller parameters are zero-extended to i64 if required by the
405 // target ABI.
406 AttributeList SanCovTraceCmpZeroExtAL;
407 SanCovTraceCmpZeroExtAL =
408 SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 0, Attribute::ZExt);
409 SanCovTraceCmpZeroExtAL =
410 SanCovTraceCmpZeroExtAL.addParamAttribute(*C, 1, Attribute::ZExt);
411
412 SanCovTraceCmpFunction[0] =
413 M.getOrInsertFunction(Name: SanCovTraceCmp1, AttributeList: SanCovTraceCmpZeroExtAL, RetTy: VoidTy,
414 Args: IRB.getInt8Ty(), Args: IRB.getInt8Ty());
415 SanCovTraceCmpFunction[1] =
416 M.getOrInsertFunction(Name: SanCovTraceCmp2, AttributeList: SanCovTraceCmpZeroExtAL, RetTy: VoidTy,
417 Args: IRB.getInt16Ty(), Args: IRB.getInt16Ty());
418 SanCovTraceCmpFunction[2] =
419 M.getOrInsertFunction(Name: SanCovTraceCmp4, AttributeList: SanCovTraceCmpZeroExtAL, RetTy: VoidTy,
420 Args: IRB.getInt32Ty(), Args: IRB.getInt32Ty());
421 SanCovTraceCmpFunction[3] =
422 M.getOrInsertFunction(Name: SanCovTraceCmp8, RetTy: VoidTy, Args: Int64Ty, Args: Int64Ty);
423
424 SanCovTraceConstCmpFunction[0] = M.getOrInsertFunction(
425 Name: SanCovTraceConstCmp1, AttributeList: SanCovTraceCmpZeroExtAL, RetTy: VoidTy, Args: Int8Ty, Args: Int8Ty);
426 SanCovTraceConstCmpFunction[1] = M.getOrInsertFunction(
427 Name: SanCovTraceConstCmp2, AttributeList: SanCovTraceCmpZeroExtAL, RetTy: VoidTy, Args: Int16Ty, Args: Int16Ty);
428 SanCovTraceConstCmpFunction[2] = M.getOrInsertFunction(
429 Name: SanCovTraceConstCmp4, AttributeList: SanCovTraceCmpZeroExtAL, RetTy: VoidTy, Args: Int32Ty, Args: Int32Ty);
430 SanCovTraceConstCmpFunction[3] =
431 M.getOrInsertFunction(Name: SanCovTraceConstCmp8, RetTy: VoidTy, Args: Int64Ty, Args: Int64Ty);
432
433 // Loads.
434 SanCovLoadFunction[0] = M.getOrInsertFunction(Name: SanCovLoad1, RetTy: VoidTy, Args: PtrTy);
435 SanCovLoadFunction[1] =
436 M.getOrInsertFunction(Name: SanCovLoad2, RetTy: VoidTy, Args: PtrTy);
437 SanCovLoadFunction[2] =
438 M.getOrInsertFunction(Name: SanCovLoad4, RetTy: VoidTy, Args: PtrTy);
439 SanCovLoadFunction[3] =
440 M.getOrInsertFunction(Name: SanCovLoad8, RetTy: VoidTy, Args: PtrTy);
441 SanCovLoadFunction[4] =
442 M.getOrInsertFunction(Name: SanCovLoad16, RetTy: VoidTy, Args: PtrTy);
443 // Stores.
444 SanCovStoreFunction[0] =
445 M.getOrInsertFunction(Name: SanCovStore1, RetTy: VoidTy, Args: PtrTy);
446 SanCovStoreFunction[1] =
447 M.getOrInsertFunction(Name: SanCovStore2, RetTy: VoidTy, Args: PtrTy);
448 SanCovStoreFunction[2] =
449 M.getOrInsertFunction(Name: SanCovStore4, RetTy: VoidTy, Args: PtrTy);
450 SanCovStoreFunction[3] =
451 M.getOrInsertFunction(Name: SanCovStore8, RetTy: VoidTy, Args: PtrTy);
452 SanCovStoreFunction[4] =
453 M.getOrInsertFunction(Name: SanCovStore16, RetTy: VoidTy, Args: PtrTy);
454
455 {
456 AttributeList AL;
457 AL = AL.addParamAttribute(*C, 0, Attribute::ZExt);
458 SanCovTraceDivFunction[0] =
459 M.getOrInsertFunction(Name: SanCovTraceDiv4, AttributeList: AL, RetTy: VoidTy, Args: IRB.getInt32Ty());
460 }
461 SanCovTraceDivFunction[1] =
462 M.getOrInsertFunction(Name: SanCovTraceDiv8, RetTy: VoidTy, Args: Int64Ty);
463 SanCovTraceGepFunction =
464 M.getOrInsertFunction(Name: SanCovTraceGep, RetTy: VoidTy, Args: IntptrTy);
465 SanCovTraceSwitchFunction =
466 M.getOrInsertFunction(Name: SanCovTraceSwitchName, RetTy: VoidTy, Args: Int64Ty, Args: PtrTy);
467
468 Constant *SanCovLowestStackConstant =
469 M.getOrInsertGlobal(Name: SanCovLowestStackName, Ty: IntptrTy);
470 SanCovLowestStack = dyn_cast<GlobalVariable>(Val: SanCovLowestStackConstant);
471 if (!SanCovLowestStack || SanCovLowestStack->getValueType() != IntptrTy) {
472 C->emitError(ErrorStr: StringRef("'") + SanCovLowestStackName +
473 "' should not be declared by the user");
474 return true;
475 }
476 SanCovLowestStack->setThreadLocalMode(
477 GlobalValue::ThreadLocalMode::InitialExecTLSModel);
478 if (Options.StackDepth && !SanCovLowestStack->isDeclaration())
479 SanCovLowestStack->setInitializer(Constant::getAllOnesValue(Ty: IntptrTy));
480
481 SanCovTracePC = M.getOrInsertFunction(Name: SanCovTracePCName, RetTy: VoidTy);
482 SanCovTracePCGuard =
483 M.getOrInsertFunction(Name: SanCovTracePCGuardName, RetTy: VoidTy, Args: PtrTy);
484
485 for (auto &F : M)
486 instrumentFunction(F);
487
488 Function *Ctor = nullptr;
489
490 if (FunctionGuardArray)
491 Ctor = CreateInitCallsForSections(M, CtorName: SanCovModuleCtorTracePcGuardName,
492 InitFunctionName: SanCovTracePCGuardInitName, Ty: Int32Ty,
493 Section: SanCovGuardsSectionName);
494 if (Function8bitCounterArray)
495 Ctor = CreateInitCallsForSections(M, CtorName: SanCovModuleCtor8bitCountersName,
496 InitFunctionName: SanCov8bitCountersInitName, Ty: Int8Ty,
497 Section: SanCovCountersSectionName);
498 if (FunctionBoolArray) {
499 Ctor = CreateInitCallsForSections(M, CtorName: SanCovModuleCtorBoolFlagName,
500 InitFunctionName: SanCovBoolFlagInitName, Ty: Int1Ty,
501 Section: SanCovBoolFlagSectionName);
502 }
503 if (Ctor && Options.PCTable) {
504 auto SecStartEnd = CreateSecStartEnd(M, Section: SanCovPCsSectionName, Ty: IntptrTy);
505 FunctionCallee InitFunction = declareSanitizerInitFunction(
506 M, InitName: SanCovPCsInitName, InitArgTypes: {PtrTy, PtrTy});
507 IRBuilder<> IRBCtor(Ctor->getEntryBlock().getTerminator());
508 IRBCtor.CreateCall(Callee: InitFunction, Args: {SecStartEnd.first, SecStartEnd.second});
509 }
510
511 if (Ctor && Options.CollectControlFlow) {
512 auto SecStartEnd = CreateSecStartEnd(M, Section: SanCovCFsSectionName, Ty: IntptrTy);
513 FunctionCallee InitFunction = declareSanitizerInitFunction(
514 M, InitName: SanCovCFsInitName, InitArgTypes: {PtrTy, PtrTy});
515 IRBuilder<> IRBCtor(Ctor->getEntryBlock().getTerminator());
516 IRBCtor.CreateCall(Callee: InitFunction, Args: {SecStartEnd.first, SecStartEnd.second});
517 }
518
519 appendToUsed(M, Values: GlobalsToAppendToUsed);
520 appendToCompilerUsed(M, Values: GlobalsToAppendToCompilerUsed);
521 return true;
522}
523
524// True if block has successors and it dominates all of them.
525static bool isFullDominator(const BasicBlock *BB, const DominatorTree &DT) {
526 if (succ_empty(BB))
527 return false;
528
529 return llvm::all_of(Range: successors(BB), P: [&](const BasicBlock *SUCC) {
530 return DT.dominates(A: BB, B: SUCC);
531 });
532}
533
534// True if block has predecessors and it postdominates all of them.
535static bool isFullPostDominator(const BasicBlock *BB,
536 const PostDominatorTree &PDT) {
537 if (pred_empty(BB))
538 return false;
539
540 return llvm::all_of(Range: predecessors(BB), P: [&](const BasicBlock *PRED) {
541 return PDT.dominates(A: BB, B: PRED);
542 });
543}
544
545static bool shouldInstrumentBlock(const Function &F, const BasicBlock *BB,
546 const DominatorTree &DT,
547 const PostDominatorTree &PDT,
548 const SanitizerCoverageOptions &Options) {
549 // Don't insert coverage for blocks containing nothing but unreachable: we
550 // will never call __sanitizer_cov() for them, so counting them in
551 // NumberOfInstrumentedBlocks() might complicate calculation of code coverage
552 // percentage. Also, unreachable instructions frequently have no debug
553 // locations.
554 if (isa<UnreachableInst>(Val: BB->getFirstNonPHIOrDbgOrLifetime()))
555 return false;
556
557 // Don't insert coverage into blocks without a valid insertion point
558 // (catchswitch blocks).
559 if (BB->getFirstInsertionPt() == BB->end())
560 return false;
561
562 if (Options.NoPrune || &F.getEntryBlock() == BB)
563 return true;
564
565 if (Options.CoverageType == SanitizerCoverageOptions::SCK_Function &&
566 &F.getEntryBlock() != BB)
567 return false;
568
569 // Do not instrument full dominators, or full post-dominators with multiple
570 // predecessors.
571 return !isFullDominator(BB, DT)
572 && !(isFullPostDominator(BB, PDT) && !BB->getSinglePredecessor());
573}
574
575// Returns true iff From->To is a backedge.
576// A twist here is that we treat From->To as a backedge if
577// * To dominates From or
578// * To->UniqueSuccessor dominates From
579static bool IsBackEdge(BasicBlock *From, BasicBlock *To,
580 const DominatorTree &DT) {
581 if (DT.dominates(A: To, B: From))
582 return true;
583 if (auto Next = To->getUniqueSuccessor())
584 if (DT.dominates(A: Next, B: From))
585 return true;
586 return false;
587}
588
589// Prunes uninteresting Cmp instrumentation:
590// * CMP instructions that feed into loop backedge branch.
591//
592// Note that Cmp pruning is controlled by the same flag as the
593// BB pruning.
594static bool IsInterestingCmp(ICmpInst *CMP, const DominatorTree &DT,
595 const SanitizerCoverageOptions &Options) {
596 if (!Options.NoPrune)
597 if (CMP->hasOneUse())
598 if (auto BR = dyn_cast<BranchInst>(Val: CMP->user_back()))
599 for (BasicBlock *B : BR->successors())
600 if (IsBackEdge(From: BR->getParent(), To: B, DT))
601 return false;
602 return true;
603}
604
605void ModuleSanitizerCoverage::instrumentFunction(Function &F) {
606 if (F.empty())
607 return;
608 if (F.getName().contains(Other: ".module_ctor"))
609 return; // Should not instrument sanitizer init functions.
610 if (F.getName().starts_with(Prefix: "__sanitizer_"))
611 return; // Don't instrument __sanitizer_* callbacks.
612 // Don't touch available_externally functions, their actual body is elewhere.
613 if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage)
614 return;
615 // Don't instrument MSVC CRT configuration helpers. They may run before normal
616 // initialization.
617 if (F.getName() == "__local_stdio_printf_options" ||
618 F.getName() == "__local_stdio_scanf_options")
619 return;
620 if (isa<UnreachableInst>(Val: F.getEntryBlock().getTerminator()))
621 return;
622 // Don't instrument functions using SEH for now. Splitting basic blocks like
623 // we do for coverage breaks WinEHPrepare.
624 // FIXME: Remove this when SEH no longer uses landingpad pattern matching.
625 if (F.hasPersonalityFn() &&
626 isAsynchronousEHPersonality(Pers: classifyEHPersonality(Pers: F.getPersonalityFn())))
627 return;
628 if (Allowlist && !Allowlist->inSection(Section: "coverage", Prefix: "fun", Query: F.getName()))
629 return;
630 if (Blocklist && Blocklist->inSection(Section: "coverage", Prefix: "fun", Query: F.getName()))
631 return;
632 if (F.hasFnAttribute(Attribute::NoSanitizeCoverage))
633 return;
634 if (Options.CoverageType >= SanitizerCoverageOptions::SCK_Edge) {
635 SplitAllCriticalEdges(
636 F, Options: CriticalEdgeSplittingOptions().setIgnoreUnreachableDests());
637 }
638 SmallVector<Instruction *, 8> IndirCalls;
639 SmallVector<BasicBlock *, 16> BlocksToInstrument;
640 SmallVector<Instruction *, 8> CmpTraceTargets;
641 SmallVector<Instruction *, 8> SwitchTraceTargets;
642 SmallVector<BinaryOperator *, 8> DivTraceTargets;
643 SmallVector<GetElementPtrInst *, 8> GepTraceTargets;
644 SmallVector<LoadInst *, 8> Loads;
645 SmallVector<StoreInst *, 8> Stores;
646
647 const DominatorTree &DT = DTCallback(F);
648 const PostDominatorTree &PDT = PDTCallback(F);
649 bool IsLeafFunc = true;
650
651 for (auto &BB : F) {
652 if (shouldInstrumentBlock(F, BB: &BB, DT, PDT, Options))
653 BlocksToInstrument.push_back(Elt: &BB);
654 for (auto &Inst : BB) {
655 if (Options.IndirectCalls) {
656 CallBase *CB = dyn_cast<CallBase>(Val: &Inst);
657 if (CB && CB->isIndirectCall())
658 IndirCalls.push_back(Elt: &Inst);
659 }
660 if (Options.TraceCmp) {
661 if (ICmpInst *CMP = dyn_cast<ICmpInst>(Val: &Inst))
662 if (IsInterestingCmp(CMP, DT, Options))
663 CmpTraceTargets.push_back(Elt: &Inst);
664 if (isa<SwitchInst>(Val: &Inst))
665 SwitchTraceTargets.push_back(Elt: &Inst);
666 }
667 if (Options.TraceDiv)
668 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(Val: &Inst))
669 if (BO->getOpcode() == Instruction::SDiv ||
670 BO->getOpcode() == Instruction::UDiv)
671 DivTraceTargets.push_back(Elt: BO);
672 if (Options.TraceGep)
673 if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Val: &Inst))
674 GepTraceTargets.push_back(Elt: GEP);
675 if (Options.TraceLoads)
676 if (LoadInst *LI = dyn_cast<LoadInst>(Val: &Inst))
677 Loads.push_back(Elt: LI);
678 if (Options.TraceStores)
679 if (StoreInst *SI = dyn_cast<StoreInst>(Val: &Inst))
680 Stores.push_back(Elt: SI);
681 if (Options.StackDepth)
682 if (isa<InvokeInst>(Val: Inst) ||
683 (isa<CallInst>(Val: Inst) && !isa<IntrinsicInst>(Val: Inst)))
684 IsLeafFunc = false;
685 }
686 }
687
688 if (Options.CollectControlFlow)
689 createFunctionControlFlow(F);
690
691 InjectCoverage(F, AllBlocks: BlocksToInstrument, IsLeafFunc);
692 InjectCoverageForIndirectCalls(F, IndirCalls);
693 InjectTraceForCmp(F, CmpTraceTargets);
694 InjectTraceForSwitch(F, SwitchTraceTargets);
695 InjectTraceForDiv(F, DivTraceTargets);
696 InjectTraceForGep(F, GepTraceTargets);
697 InjectTraceForLoadsAndStores(F, Loads, Stores);
698}
699
700GlobalVariable *ModuleSanitizerCoverage::CreateFunctionLocalArrayInSection(
701 size_t NumElements, Function &F, Type *Ty, const char *Section) {
702 ArrayType *ArrayTy = ArrayType::get(ElementType: Ty, NumElements);
703 auto Array = new GlobalVariable(
704 *CurModule, ArrayTy, false, GlobalVariable::PrivateLinkage,
705 Constant::getNullValue(Ty: ArrayTy), "__sancov_gen_");
706
707 if (TargetTriple.supportsCOMDAT() &&
708 (TargetTriple.isOSBinFormatELF() || !F.isInterposable()))
709 if (auto Comdat = getOrCreateFunctionComdat(F, T&: TargetTriple))
710 Array->setComdat(Comdat);
711 Array->setSection(getSectionName(Section));
712 Array->setAlignment(Align(DL->getTypeStoreSize(Ty).getFixedValue()));
713
714 // sancov_pcs parallels the other metadata section(s). Optimizers (e.g.
715 // GlobalOpt/ConstantMerge) may not discard sancov_pcs and the other
716 // section(s) as a unit, so we conservatively retain all unconditionally in
717 // the compiler.
718 //
719 // With comdat (COFF/ELF), the linker can guarantee the associated sections
720 // will be retained or discarded as a unit, so llvm.compiler.used is
721 // sufficient. Otherwise, conservatively make all of them retained by the
722 // linker.
723 if (Array->hasComdat())
724 GlobalsToAppendToCompilerUsed.push_back(Elt: Array);
725 else
726 GlobalsToAppendToUsed.push_back(Elt: Array);
727
728 return Array;
729}
730
731GlobalVariable *
732ModuleSanitizerCoverage::CreatePCArray(Function &F,
733 ArrayRef<BasicBlock *> AllBlocks) {
734 size_t N = AllBlocks.size();
735 assert(N);
736 SmallVector<Constant *, 32> PCs;
737 IRBuilder<> IRB(&*F.getEntryBlock().getFirstInsertionPt());
738 for (size_t i = 0; i < N; i++) {
739 if (&F.getEntryBlock() == AllBlocks[i]) {
740 PCs.push_back(Elt: (Constant *)IRB.CreatePointerCast(V: &F, DestTy: PtrTy));
741 PCs.push_back(Elt: (Constant *)IRB.CreateIntToPtr(
742 V: ConstantInt::get(Ty: IntptrTy, V: 1), DestTy: PtrTy));
743 } else {
744 PCs.push_back(Elt: (Constant *)IRB.CreatePointerCast(
745 V: BlockAddress::get(BB: AllBlocks[i]), DestTy: PtrTy));
746 PCs.push_back(Elt: Constant::getNullValue(Ty: PtrTy));
747 }
748 }
749 auto *PCArray = CreateFunctionLocalArrayInSection(NumElements: N * 2, F, Ty: PtrTy,
750 Section: SanCovPCsSectionName);
751 PCArray->setInitializer(
752 ConstantArray::get(T: ArrayType::get(ElementType: PtrTy, NumElements: N * 2), V: PCs));
753 PCArray->setConstant(true);
754
755 return PCArray;
756}
757
758void ModuleSanitizerCoverage::CreateFunctionLocalArrays(
759 Function &F, ArrayRef<BasicBlock *> AllBlocks) {
760 if (Options.TracePCGuard)
761 FunctionGuardArray = CreateFunctionLocalArrayInSection(
762 NumElements: AllBlocks.size(), F, Ty: Int32Ty, Section: SanCovGuardsSectionName);
763
764 if (Options.Inline8bitCounters)
765 Function8bitCounterArray = CreateFunctionLocalArrayInSection(
766 NumElements: AllBlocks.size(), F, Ty: Int8Ty, Section: SanCovCountersSectionName);
767 if (Options.InlineBoolFlag)
768 FunctionBoolArray = CreateFunctionLocalArrayInSection(
769 NumElements: AllBlocks.size(), F, Ty: Int1Ty, Section: SanCovBoolFlagSectionName);
770
771 if (Options.PCTable)
772 FunctionPCsArray = CreatePCArray(F, AllBlocks);
773}
774
775bool ModuleSanitizerCoverage::InjectCoverage(Function &F,
776 ArrayRef<BasicBlock *> AllBlocks,
777 bool IsLeafFunc) {
778 if (AllBlocks.empty()) return false;
779 CreateFunctionLocalArrays(F, AllBlocks);
780 for (size_t i = 0, N = AllBlocks.size(); i < N; i++)
781 InjectCoverageAtBlock(F, BB&: *AllBlocks[i], Idx: i, IsLeafFunc);
782 return true;
783}
784
785// On every indirect call we call a run-time function
786// __sanitizer_cov_indir_call* with two parameters:
787// - callee address,
788// - global cache array that contains CacheSize pointers (zero-initialized).
789// The cache is used to speed up recording the caller-callee pairs.
790// The address of the caller is passed implicitly via caller PC.
791// CacheSize is encoded in the name of the run-time function.
792void ModuleSanitizerCoverage::InjectCoverageForIndirectCalls(
793 Function &F, ArrayRef<Instruction *> IndirCalls) {
794 if (IndirCalls.empty())
795 return;
796 assert(Options.TracePC || Options.TracePCGuard ||
797 Options.Inline8bitCounters || Options.InlineBoolFlag);
798 for (auto *I : IndirCalls) {
799 InstrumentationIRBuilder IRB(I);
800 CallBase &CB = cast<CallBase>(Val&: *I);
801 Value *Callee = CB.getCalledOperand();
802 if (isa<InlineAsm>(Val: Callee))
803 continue;
804 IRB.CreateCall(Callee: SanCovTracePCIndir, Args: IRB.CreatePointerCast(V: Callee, DestTy: IntptrTy));
805 }
806}
807
808// For every switch statement we insert a call:
809// __sanitizer_cov_trace_switch(CondValue,
810// {NumCases, ValueSizeInBits, Case0Value, Case1Value, Case2Value, ... })
811
812void ModuleSanitizerCoverage::InjectTraceForSwitch(
813 Function &, ArrayRef<Instruction *> SwitchTraceTargets) {
814 for (auto *I : SwitchTraceTargets) {
815 if (SwitchInst *SI = dyn_cast<SwitchInst>(Val: I)) {
816 InstrumentationIRBuilder IRB(I);
817 SmallVector<Constant *, 16> Initializers;
818 Value *Cond = SI->getCondition();
819 if (Cond->getType()->getScalarSizeInBits() >
820 Int64Ty->getScalarSizeInBits())
821 continue;
822 Initializers.push_back(Elt: ConstantInt::get(Ty: Int64Ty, V: SI->getNumCases()));
823 Initializers.push_back(
824 Elt: ConstantInt::get(Ty: Int64Ty, V: Cond->getType()->getScalarSizeInBits()));
825 if (Cond->getType()->getScalarSizeInBits() <
826 Int64Ty->getScalarSizeInBits())
827 Cond = IRB.CreateIntCast(V: Cond, DestTy: Int64Ty, isSigned: false);
828 for (auto It : SI->cases()) {
829 ConstantInt *C = It.getCaseValue();
830 if (C->getType()->getScalarSizeInBits() < 64)
831 C = ConstantInt::get(Context&: C->getContext(), V: C->getValue().zext(width: 64));
832 Initializers.push_back(Elt: C);
833 }
834 llvm::sort(C: drop_begin(RangeOrContainer&: Initializers, N: 2),
835 Comp: [](const Constant *A, const Constant *B) {
836 return cast<ConstantInt>(Val: A)->getLimitedValue() <
837 cast<ConstantInt>(Val: B)->getLimitedValue();
838 });
839 ArrayType *ArrayOfInt64Ty = ArrayType::get(ElementType: Int64Ty, NumElements: Initializers.size());
840 GlobalVariable *GV = new GlobalVariable(
841 *CurModule, ArrayOfInt64Ty, false, GlobalVariable::InternalLinkage,
842 ConstantArray::get(T: ArrayOfInt64Ty, V: Initializers),
843 "__sancov_gen_cov_switch_values");
844 IRB.CreateCall(Callee: SanCovTraceSwitchFunction, Args: {Cond, GV});
845 }
846 }
847}
848
849void ModuleSanitizerCoverage::InjectTraceForDiv(
850 Function &, ArrayRef<BinaryOperator *> DivTraceTargets) {
851 for (auto *BO : DivTraceTargets) {
852 InstrumentationIRBuilder IRB(BO);
853 Value *A1 = BO->getOperand(i_nocapture: 1);
854 if (isa<ConstantInt>(Val: A1)) continue;
855 if (!A1->getType()->isIntegerTy())
856 continue;
857 uint64_t TypeSize = DL->getTypeStoreSizeInBits(Ty: A1->getType());
858 int CallbackIdx = TypeSize == 32 ? 0 :
859 TypeSize == 64 ? 1 : -1;
860 if (CallbackIdx < 0) continue;
861 auto Ty = Type::getIntNTy(C&: *C, N: TypeSize);
862 IRB.CreateCall(Callee: SanCovTraceDivFunction[CallbackIdx],
863 Args: {IRB.CreateIntCast(V: A1, DestTy: Ty, isSigned: true)});
864 }
865}
866
867void ModuleSanitizerCoverage::InjectTraceForGep(
868 Function &, ArrayRef<GetElementPtrInst *> GepTraceTargets) {
869 for (auto *GEP : GepTraceTargets) {
870 InstrumentationIRBuilder IRB(GEP);
871 for (Use &Idx : GEP->indices())
872 if (!isa<ConstantInt>(Val: Idx) && Idx->getType()->isIntegerTy())
873 IRB.CreateCall(Callee: SanCovTraceGepFunction,
874 Args: {IRB.CreateIntCast(V: Idx, DestTy: IntptrTy, isSigned: true)});
875 }
876}
877
878void ModuleSanitizerCoverage::InjectTraceForLoadsAndStores(
879 Function &, ArrayRef<LoadInst *> Loads, ArrayRef<StoreInst *> Stores) {
880 auto CallbackIdx = [&](Type *ElementTy) -> int {
881 uint64_t TypeSize = DL->getTypeStoreSizeInBits(Ty: ElementTy);
882 return TypeSize == 8 ? 0
883 : TypeSize == 16 ? 1
884 : TypeSize == 32 ? 2
885 : TypeSize == 64 ? 3
886 : TypeSize == 128 ? 4
887 : -1;
888 };
889 for (auto *LI : Loads) {
890 InstrumentationIRBuilder IRB(LI);
891 auto Ptr = LI->getPointerOperand();
892 int Idx = CallbackIdx(LI->getType());
893 if (Idx < 0)
894 continue;
895 IRB.CreateCall(Callee: SanCovLoadFunction[Idx], Args: Ptr);
896 }
897 for (auto *SI : Stores) {
898 InstrumentationIRBuilder IRB(SI);
899 auto Ptr = SI->getPointerOperand();
900 int Idx = CallbackIdx(SI->getValueOperand()->getType());
901 if (Idx < 0)
902 continue;
903 IRB.CreateCall(Callee: SanCovStoreFunction[Idx], Args: Ptr);
904 }
905}
906
907void ModuleSanitizerCoverage::InjectTraceForCmp(
908 Function &, ArrayRef<Instruction *> CmpTraceTargets) {
909 for (auto *I : CmpTraceTargets) {
910 if (ICmpInst *ICMP = dyn_cast<ICmpInst>(Val: I)) {
911 InstrumentationIRBuilder IRB(ICMP);
912 Value *A0 = ICMP->getOperand(i_nocapture: 0);
913 Value *A1 = ICMP->getOperand(i_nocapture: 1);
914 if (!A0->getType()->isIntegerTy())
915 continue;
916 uint64_t TypeSize = DL->getTypeStoreSizeInBits(Ty: A0->getType());
917 int CallbackIdx = TypeSize == 8 ? 0 :
918 TypeSize == 16 ? 1 :
919 TypeSize == 32 ? 2 :
920 TypeSize == 64 ? 3 : -1;
921 if (CallbackIdx < 0) continue;
922 // __sanitizer_cov_trace_cmp((type_size << 32) | predicate, A0, A1);
923 auto CallbackFunc = SanCovTraceCmpFunction[CallbackIdx];
924 bool FirstIsConst = isa<ConstantInt>(Val: A0);
925 bool SecondIsConst = isa<ConstantInt>(Val: A1);
926 // If both are const, then we don't need such a comparison.
927 if (FirstIsConst && SecondIsConst) continue;
928 // If only one is const, then make it the first callback argument.
929 if (FirstIsConst || SecondIsConst) {
930 CallbackFunc = SanCovTraceConstCmpFunction[CallbackIdx];
931 if (SecondIsConst)
932 std::swap(a&: A0, b&: A1);
933 }
934
935 auto Ty = Type::getIntNTy(C&: *C, N: TypeSize);
936 IRB.CreateCall(Callee: CallbackFunc, Args: {IRB.CreateIntCast(V: A0, DestTy: Ty, isSigned: true),
937 IRB.CreateIntCast(V: A1, DestTy: Ty, isSigned: true)});
938 }
939 }
940}
941
942void ModuleSanitizerCoverage::InjectCoverageAtBlock(Function &F, BasicBlock &BB,
943 size_t Idx,
944 bool IsLeafFunc) {
945 BasicBlock::iterator IP = BB.getFirstInsertionPt();
946 bool IsEntryBB = &BB == &F.getEntryBlock();
947 DebugLoc EntryLoc;
948 if (IsEntryBB) {
949 if (auto SP = F.getSubprogram())
950 EntryLoc = DILocation::get(Context&: SP->getContext(), Line: SP->getScopeLine(), Column: 0, Scope: SP);
951 // Keep static allocas and llvm.localescape calls in the entry block. Even
952 // if we aren't splitting the block, it's nice for allocas to be before
953 // calls.
954 IP = PrepareToSplitEntryBlock(BB, IP);
955 }
956
957 InstrumentationIRBuilder IRB(&*IP);
958 if (EntryLoc)
959 IRB.SetCurrentDebugLocation(EntryLoc);
960 if (Options.TracePC) {
961 IRB.CreateCall(Callee: SanCovTracePC)
962 ->setCannotMerge(); // gets the PC using GET_CALLER_PC.
963 }
964 if (Options.TracePCGuard) {
965 auto GuardPtr = IRB.CreateIntToPtr(
966 V: IRB.CreateAdd(LHS: IRB.CreatePointerCast(V: FunctionGuardArray, DestTy: IntptrTy),
967 RHS: ConstantInt::get(Ty: IntptrTy, V: Idx * 4)),
968 DestTy: PtrTy);
969 IRB.CreateCall(Callee: SanCovTracePCGuard, Args: GuardPtr)->setCannotMerge();
970 }
971 if (Options.Inline8bitCounters) {
972 auto CounterPtr = IRB.CreateGEP(
973 Ty: Function8bitCounterArray->getValueType(), Ptr: Function8bitCounterArray,
974 IdxList: {ConstantInt::get(Ty: IntptrTy, V: 0), ConstantInt::get(Ty: IntptrTy, V: Idx)});
975 auto Load = IRB.CreateLoad(Ty: Int8Ty, Ptr: CounterPtr);
976 auto Inc = IRB.CreateAdd(LHS: Load, RHS: ConstantInt::get(Ty: Int8Ty, V: 1));
977 auto Store = IRB.CreateStore(Val: Inc, Ptr: CounterPtr);
978 Load->setNoSanitizeMetadata();
979 Store->setNoSanitizeMetadata();
980 }
981 if (Options.InlineBoolFlag) {
982 auto FlagPtr = IRB.CreateGEP(
983 Ty: FunctionBoolArray->getValueType(), Ptr: FunctionBoolArray,
984 IdxList: {ConstantInt::get(Ty: IntptrTy, V: 0), ConstantInt::get(Ty: IntptrTy, V: Idx)});
985 auto Load = IRB.CreateLoad(Ty: Int1Ty, Ptr: FlagPtr);
986 auto ThenTerm = SplitBlockAndInsertIfThen(
987 Cond: IRB.CreateIsNull(Arg: Load), SplitBefore: &*IP, Unreachable: false,
988 BranchWeights: MDBuilder(IRB.getContext()).createUnlikelyBranchWeights());
989 IRBuilder<> ThenIRB(ThenTerm);
990 auto Store = ThenIRB.CreateStore(Val: ConstantInt::getTrue(Ty: Int1Ty), Ptr: FlagPtr);
991 Load->setNoSanitizeMetadata();
992 Store->setNoSanitizeMetadata();
993 }
994 if (Options.StackDepth && IsEntryBB && !IsLeafFunc) {
995 // Check stack depth. If it's the deepest so far, record it.
996 Module *M = F.getParent();
997 Function *GetFrameAddr = Intrinsic::getDeclaration(
998 M, Intrinsic::id: frameaddress,
999 Tys: IRB.getPtrTy(AddrSpace: M->getDataLayout().getAllocaAddrSpace()));
1000 auto FrameAddrPtr =
1001 IRB.CreateCall(Callee: GetFrameAddr, Args: {Constant::getNullValue(Ty: Int32Ty)});
1002 auto FrameAddrInt = IRB.CreatePtrToInt(V: FrameAddrPtr, DestTy: IntptrTy);
1003 auto LowestStack = IRB.CreateLoad(Ty: IntptrTy, Ptr: SanCovLowestStack);
1004 auto IsStackLower = IRB.CreateICmpULT(LHS: FrameAddrInt, RHS: LowestStack);
1005 auto ThenTerm = SplitBlockAndInsertIfThen(
1006 IsStackLower, &*IP, false,
1007 MDBuilder(IRB.getContext()).createUnlikelyBranchWeights());
1008 IRBuilder<> ThenIRB(ThenTerm);
1009 auto Store = ThenIRB.CreateStore(Val: FrameAddrInt, Ptr: SanCovLowestStack);
1010 LowestStack->setNoSanitizeMetadata();
1011 Store->setNoSanitizeMetadata();
1012 }
1013}
1014
1015std::string
1016ModuleSanitizerCoverage::getSectionName(const std::string &Section) const {
1017 if (TargetTriple.isOSBinFormatCOFF()) {
1018 if (Section == SanCovCountersSectionName)
1019 return ".SCOV$CM";
1020 if (Section == SanCovBoolFlagSectionName)
1021 return ".SCOV$BM";
1022 if (Section == SanCovPCsSectionName)
1023 return ".SCOVP$M";
1024 return ".SCOV$GM"; // For SanCovGuardsSectionName.
1025 }
1026 if (TargetTriple.isOSBinFormatMachO())
1027 return "__DATA,__" + Section;
1028 return "__" + Section;
1029}
1030
1031std::string
1032ModuleSanitizerCoverage::getSectionStart(const std::string &Section) const {
1033 if (TargetTriple.isOSBinFormatMachO())
1034 return "\1section$start$__DATA$__" + Section;
1035 return "__start___" + Section;
1036}
1037
1038std::string
1039ModuleSanitizerCoverage::getSectionEnd(const std::string &Section) const {
1040 if (TargetTriple.isOSBinFormatMachO())
1041 return "\1section$end$__DATA$__" + Section;
1042 return "__stop___" + Section;
1043}
1044
1045void ModuleSanitizerCoverage::createFunctionControlFlow(Function &F) {
1046 SmallVector<Constant *, 32> CFs;
1047 IRBuilder<> IRB(&*F.getEntryBlock().getFirstInsertionPt());
1048
1049 for (auto &BB : F) {
1050 // blockaddress can not be used on function's entry block.
1051 if (&BB == &F.getEntryBlock())
1052 CFs.push_back(Elt: (Constant *)IRB.CreatePointerCast(V: &F, DestTy: PtrTy));
1053 else
1054 CFs.push_back(Elt: (Constant *)IRB.CreatePointerCast(V: BlockAddress::get(BB: &BB),
1055 DestTy: PtrTy));
1056
1057 for (auto SuccBB : successors(BB: &BB)) {
1058 assert(SuccBB != &F.getEntryBlock());
1059 CFs.push_back(Elt: (Constant *)IRB.CreatePointerCast(V: BlockAddress::get(BB: SuccBB),
1060 DestTy: PtrTy));
1061 }
1062
1063 CFs.push_back(Elt: (Constant *)Constant::getNullValue(Ty: PtrTy));
1064
1065 for (auto &Inst : BB) {
1066 if (CallBase *CB = dyn_cast<CallBase>(Val: &Inst)) {
1067 if (CB->isIndirectCall()) {
1068 // TODO(navidem): handle indirect calls, for now mark its existence.
1069 CFs.push_back(Elt: (Constant *)IRB.CreateIntToPtr(
1070 V: ConstantInt::get(Ty: IntptrTy, V: -1), DestTy: PtrTy));
1071 } else {
1072 auto CalledF = CB->getCalledFunction();
1073 if (CalledF && !CalledF->isIntrinsic())
1074 CFs.push_back(
1075 Elt: (Constant *)IRB.CreatePointerCast(V: CalledF, DestTy: PtrTy));
1076 }
1077 }
1078 }
1079
1080 CFs.push_back(Elt: (Constant *)Constant::getNullValue(Ty: PtrTy));
1081 }
1082
1083 FunctionCFsArray = CreateFunctionLocalArrayInSection(
1084 NumElements: CFs.size(), F, Ty: PtrTy, Section: SanCovCFsSectionName);
1085 FunctionCFsArray->setInitializer(
1086 ConstantArray::get(T: ArrayType::get(ElementType: PtrTy, NumElements: CFs.size()), V: CFs));
1087 FunctionCFsArray->setConstant(true);
1088}
1089

source code of llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp