https://github.com/matts1 created https://github.com/llvm/llvm-project/pull/127161
See https://issues.chromium.org/issues/351909443 for details and benchmarks. This improves the performance of a file containing a single line, `#include <iostream>`, from ~1 second to ~100ms on my machine. >From 14560a133284f8d6e01d1bb360b738aa4a513af5 Mon Sep 17 00:00:00 2001 From: Matt Stark <m...@google.com> Date: Fri, 14 Feb 2025 14:14:03 +1100 Subject: [PATCH] [Fix] Speedup -Wunsafe-buffer-usage when using clang modules. See https://issues.chromium.org/issues/351909443 for details and benchmarks. This improves the performance of a file containing a single line, `#include <iostream>`, from ~1 second to ~100ms on my machine. --- clang/lib/Sema/AnalysisBasedWarnings.cpp | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/clang/lib/Sema/AnalysisBasedWarnings.cpp b/clang/lib/Sema/AnalysisBasedWarnings.cpp index 589869d018657..b00e8352d9992 100644 --- a/clang/lib/Sema/AnalysisBasedWarnings.cpp +++ b/clang/lib/Sema/AnalysisBasedWarnings.cpp @@ -2546,14 +2546,27 @@ static void flushDiagnostics(Sema &S, const sema::FunctionScopeInfo *fscope) { class CallableVisitor : public DynamicRecursiveASTVisitor { private: llvm::function_ref<void(const Decl *)> Callback; + const unsigned int TUModuleID; public: - CallableVisitor(llvm::function_ref<void(const Decl *)> Callback) - : Callback(Callback) { + CallableVisitor(llvm::function_ref<void(const Decl *)> Callback, + unsigned int TUModuleID) + : Callback(Callback), TUModuleID(TUModuleID) { ShouldVisitTemplateInstantiations = true; ShouldVisitImplicitCode = false; } + bool TraverseDecl(Decl *Node) override { + // For performance reasons, only validate the current translation unit's + // module, and not modules it depends on. + // See https://issues.chromium.org/issues/351909443 for details. + if (Node->getOwningModuleID() == TUModuleID) { + return DynamicRecursiveASTVisitor::TraverseDecl(Node); + } else { + return true; + } + } + bool VisitFunctionDecl(FunctionDecl *Node) override { if (cast<DeclContext>(Node)->isDependentContext()) return true; // Not to analyze dependent decl @@ -2633,7 +2646,7 @@ void clang::sema::AnalysisBasedWarnings::IssueWarnings( SourceLocation()) || (!Diags.isIgnored(diag::warn_unsafe_buffer_libc_call, SourceLocation()) && S.getLangOpts().CPlusPlus /* only warn about libc calls in C++ */)) { - CallableVisitor(CallAnalyzers).TraverseTranslationUnitDecl(TU); + CallableVisitor(CallAnalyzers, TU->getOwningModuleID()).TraverseTranslationUnitDecl(TU); } } _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
