diff options
Diffstat (limited to 'llvm/lib/Transforms/Utils/MisExpect.cpp')
| -rw-r--r-- | llvm/lib/Transforms/Utils/MisExpect.cpp | 61 |
1 files changed, 22 insertions, 39 deletions
diff --git a/llvm/lib/Transforms/Utils/MisExpect.cpp b/llvm/lib/Transforms/Utils/MisExpect.cpp index ca7e09d..1585e9e 100644 --- a/llvm/lib/Transforms/Utils/MisExpect.cpp +++ b/llvm/lib/Transforms/Utils/MisExpect.cpp @@ -48,8 +48,6 @@ using namespace llvm; using namespace misexpect; -namespace llvm { - // Command line option to enable/disable the warning when profile data suggests // a mismatch with the use of the llvm.expect intrinsic static cl::opt<bool> PGOWarnMisExpect( @@ -63,22 +61,18 @@ static cl::opt<uint32_t> MisExpectTolerance( cl::desc("Prevents emitting diagnostics when profile counts are " "within N% of the threshold..")); -} // namespace llvm - -namespace { - -bool isMisExpectDiagEnabled(LLVMContext &Ctx) { +static bool isMisExpectDiagEnabled(const LLVMContext &Ctx) { return PGOWarnMisExpect || Ctx.getMisExpectWarningRequested(); } -uint32_t getMisExpectTolerance(LLVMContext &Ctx) { +static uint32_t getMisExpectTolerance(const LLVMContext &Ctx) { return std::max(static_cast<uint32_t>(MisExpectTolerance), Ctx.getDiagnosticsMisExpectTolerance()); } -Instruction *getInstCondition(Instruction *I) { +static const Instruction *getInstCondition(const Instruction *I) { assert(I != nullptr && "MisExpect target Instruction cannot be nullptr"); - Instruction *Ret = nullptr; + const Instruction *Ret = nullptr; if (auto *B = dyn_cast<BranchInst>(I)) { Ret = dyn_cast<Instruction>(B->getCondition()); } @@ -97,8 +91,8 @@ Instruction *getInstCondition(Instruction *I) { return Ret ? Ret : I; } -void emitMisexpectDiagnostic(Instruction *I, LLVMContext &Ctx, - uint64_t ProfCount, uint64_t TotalCount) { +static void emitMisexpectDiagnostic(const Instruction *I, LLVMContext &Ctx, + uint64_t ProfCount, uint64_t TotalCount) { double PercentageCorrect = (double)ProfCount / TotalCount; auto PerString = formatv("{0:P} ({1} / {2})", PercentageCorrect, ProfCount, TotalCount); @@ -106,20 +100,16 @@ void emitMisexpectDiagnostic(Instruction *I, LLVMContext &Ctx, "Potential performance regression from use of the llvm.expect intrinsic: " "Annotation was correct on {0} of profiled executions.", PerString); - Instruction *Cond = getInstCondition(I); + const Instruction *Cond = getInstCondition(I); if (isMisExpectDiagEnabled(Ctx)) Ctx.diagnose(DiagnosticInfoMisExpect(Cond, Twine(PerString))); OptimizationRemarkEmitter ORE(I->getParent()->getParent()); ORE.emit(OptimizationRemark(DEBUG_TYPE, "misexpect", Cond) << RemStr.str()); } -} // namespace - -namespace llvm { -namespace misexpect { - -void verifyMisExpect(Instruction &I, ArrayRef<uint32_t> RealWeights, - ArrayRef<uint32_t> ExpectedWeights) { +void misexpect::verifyMisExpect(const Instruction &I, + ArrayRef<uint32_t> RealWeights, + ArrayRef<uint32_t> ExpectedWeights) { // To determine if we emit a diagnostic, we need to compare the branch weights // from the profile to those added by the llvm.expect intrinsic. // So first, we extract the "likely" and "unlikely" weights from @@ -128,15 +118,13 @@ void verifyMisExpect(Instruction &I, ArrayRef<uint32_t> RealWeights, uint64_t LikelyBranchWeight = 0, UnlikelyBranchWeight = std::numeric_limits<uint32_t>::max(); size_t MaxIndex = 0; - for (size_t Idx = 0, End = ExpectedWeights.size(); Idx < End; Idx++) { - uint32_t V = ExpectedWeights[Idx]; + for (const auto &[Idx, V] : enumerate(ExpectedWeights)) { if (LikelyBranchWeight < V) { LikelyBranchWeight = V; MaxIndex = Idx; } - if (UnlikelyBranchWeight > V) { + if (UnlikelyBranchWeight > V) UnlikelyBranchWeight = V; - } } const uint64_t ProfiledWeight = RealWeights[MaxIndex]; @@ -161,7 +149,7 @@ void verifyMisExpect(Instruction &I, ArrayRef<uint32_t> RealWeights, uint64_t ScaledThreshold = LikelyProbablilty.scale(RealWeightsTotal); // clamp tolerance range to [0, 100) - auto Tolerance = getMisExpectTolerance(I.getContext()); + uint32_t Tolerance = getMisExpectTolerance(I.getContext()); Tolerance = std::clamp(Tolerance, 0u, 99u); // Allow users to relax checking by N% i.e., if they use a 5% tolerance, @@ -175,8 +163,8 @@ void verifyMisExpect(Instruction &I, ArrayRef<uint32_t> RealWeights, RealWeightsTotal); } -void checkBackendInstrumentation(Instruction &I, - const ArrayRef<uint32_t> RealWeights) { +void misexpect::checkBackendInstrumentation(const Instruction &I, + ArrayRef<uint32_t> RealWeights) { // Backend checking assumes any existing weight comes from an `llvm.expect` // intrinsic. However, SampleProfiling + ThinLTO add branch weights multiple // times, leading to an invalid assumption in our checking. Backend checks @@ -190,24 +178,19 @@ void checkBackendInstrumentation(Instruction &I, verifyMisExpect(I, RealWeights, ExpectedWeights); } -void checkFrontendInstrumentation(Instruction &I, - const ArrayRef<uint32_t> ExpectedWeights) { +void misexpect::checkFrontendInstrumentation( + const Instruction &I, ArrayRef<uint32_t> ExpectedWeights) { SmallVector<uint32_t> RealWeights; if (!extractBranchWeights(I, RealWeights)) return; verifyMisExpect(I, RealWeights, ExpectedWeights); } -void checkExpectAnnotations(Instruction &I, - const ArrayRef<uint32_t> ExistingWeights, - bool IsFrontend) { - if (IsFrontend) { +void misexpect::checkExpectAnnotations(const Instruction &I, + ArrayRef<uint32_t> ExistingWeights, + bool IsFrontend) { + if (IsFrontend) checkFrontendInstrumentation(I, ExistingWeights); - } else { + else checkBackendInstrumentation(I, ExistingWeights); - } } - -} // namespace misexpect -} // namespace llvm -#undef DEBUG_TYPE |