[sanitizer-coverage] add yet another flavour of coverage instrumentation: trace-pc-guard. The intent is to eventually replace all of {bool coverage, 8bit-counters, trace-pc} with just this one. LLVM part
llvm-svn: 281431
diff --git a/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp b/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
index 5a70598..63b2a6d 100644
--- a/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
+++ b/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
@@ -78,6 +78,12 @@
static const char *const SanCovModuleCtorName = "sancov.module_ctor";
static const uint64_t SanCtorAndDtorPriority = 2;
+static const char *const SanCovTracePCGuardSection = "__sancov_guards";
+static const char *const SanCovTracePCGuardName =
+ "__sanitizer_cov_trace_pc_guard";
+static const char *const SanCovTracePCGuardInitName =
+ "__sanitizer_cov_trace_pc_guard_init";
+
static cl::opt<int> ClCoverageLevel(
"sanitizer-coverage-level",
cl::desc("Sanitizer Coverage. 0: none, 1: entry block, 2: all blocks, "
@@ -101,6 +107,10 @@
cl::desc("Experimental pc tracing"),
cl::Hidden, cl::init(false));
+static cl::opt<bool> ClTracePCGuard("sanitizer-coverage-trace-pc-guard",
+ cl::desc("pc tracing with a guard"),
+ cl::Hidden, cl::init(false));
+
static cl::opt<bool>
ClCMPTracing("sanitizer-coverage-trace-compares",
cl::desc("Tracing of CMP and similar instructions"),
@@ -165,6 +175,7 @@
Options.TraceGep |= ClGEPTracing;
Options.Use8bitCounters |= ClUse8bitCounters;
Options.TracePC |= ClExperimentalTracePC;
+ Options.TracePCGuard |= ClTracePCGuard;
return Options;
}
@@ -206,7 +217,7 @@
Function *SanCovFunction;
Function *SanCovWithCheckFunction;
Function *SanCovIndirCallFunction, *SanCovTracePCIndir;
- Function *SanCovTraceEnter, *SanCovTraceBB, *SanCovTracePC;
+ Function *SanCovTraceEnter, *SanCovTraceBB, *SanCovTracePC, *SanCovTracePCGuard;
Function *SanCovTraceCmpFunction[4];
Function *SanCovTraceDivFunction[2];
Function *SanCovTraceGepFunction;
@@ -281,6 +292,8 @@
SanCovTracePC = checkSanitizerInterfaceFunction(
M.getOrInsertFunction(SanCovTracePCName, VoidTy, nullptr));
+ SanCovTracePCGuard = checkSanitizerInterfaceFunction(M.getOrInsertFunction(
+ SanCovTracePCGuardName, VoidTy, IRB.getInt8PtrTy(), nullptr));
SanCovTraceEnter = checkSanitizerInterfaceFunction(
M.getOrInsertFunction(SanCovTraceEnterName, VoidTy, Int32PtrTy, nullptr));
SanCovTraceBB = checkSanitizerInterfaceFunction(
@@ -336,8 +349,23 @@
GlobalVariable *ModuleName =
new GlobalVariable(M, ModNameStrConst->getType(), true,
GlobalValue::PrivateLinkage, ModNameStrConst);
+ if (Options.TracePCGuard) {
+ Function *CtorFunc;
+ std::string SectionName(SanCovTracePCGuardSection);
+ auto Start =
+ new GlobalVariable(M, Int8PtrTy, false, GlobalVariable::ExternalLinkage,
+ nullptr, "__start_" + SectionName);
+ auto Stop =
+ new GlobalVariable(M, Int8PtrTy, false, GlobalVariable::ExternalLinkage,
+ nullptr, "__stop_" + SectionName);
+ std::tie(CtorFunc, std::ignore) = createSanitizerCtorAndInitFunctions(
+ M, SanCovModuleCtorName, SanCovTracePCGuardInitName,
+ {Int8PtrTy, Int8PtrTy}, {IRB.CreatePointerCast(Start, Int8PtrTy),
+ IRB.CreatePointerCast(Stop, Int8PtrTy)});
- if (!Options.TracePC) {
+ appendToGlobalCtors(M, CtorFunc, SanCtorAndDtorPriority);
+
+ } else if (!Options.TracePC) {
Function *CtorFunc;
std::tie(CtorFunc, std::ignore) = createSanitizerCtorAndInitFunctions(
M, SanCovModuleCtorName, SanCovModuleInitName,
@@ -395,6 +423,8 @@
return false;
if (F.getName().find(".module_ctor") != std::string::npos)
return false; // Should not instrument sanitizer init functions.
+ if (F.getName().startswith("__sanitizer_"))
+ return false; // Don't instrument __sanitizer_* callbacks.
// Don't instrument functions using SEH for now. Splitting basic blocks like
// we do for coverage breaks WinEHPrepare.
// FIXME: Remove this when SEH no longer uses landingpad pattern matching.
@@ -631,6 +661,26 @@
if (Options.TracePC) {
IRB.CreateCall(SanCovTracePC); // gets the PC using GET_CALLER_PC.
IRB.CreateCall(EmptyAsm, {}); // Avoids callback merge.
+ } else if (Options.TracePCGuard) {
+ auto GuardVar = new GlobalVariable(*F.getParent(), IRB.getInt8Ty(), false,
+ GlobalVariable::LinkOnceODRLinkage,
+ Constant::getNullValue(IRB.getInt8Ty()),
+ "__sancov_guard." + F.getName());
+ // TODO: add debug into to GuardVar.
+ GuardVar->setSection(SanCovTracePCGuardSection);
+ auto GuardPtr = IRB.CreatePointerCast(GuardVar, IRB.getInt8PtrTy());
+ auto GuardLoad = IRB.CreateLoad(GuardPtr);
+ GuardLoad->setAtomic(AtomicOrdering::Monotonic);
+ GuardLoad->setAlignment(1);
+ SetNoSanitizeMetadata(GuardLoad); // Don't instrument with e.g. asan.
+ auto Cmp = IRB.CreateICmpNE(
+ Constant::getAllOnesValue(GuardLoad->getType()), GuardLoad);
+ auto Ins = SplitBlockAndInsertIfThen(
+ Cmp, &*IP, false, MDBuilder(*C).createBranchWeights(1, 100000));
+ IRB.SetCurrentDebugLocation(EntryLoc);
+ IRB.SetInsertPoint(Ins);
+ IRB.CreateCall(SanCovTracePCGuard, GuardPtr);
+ IRB.CreateCall(EmptyAsm, {}); // Avoids callback merge.
} else if (Options.TraceBB) {
IRB.CreateCall(IsEntryBB ? SanCovTraceEnter : SanCovTraceBB, GuardP);
} else if (UseCalls) {