https://github.com/matts1 updated https://github.com/llvm/llvm-project/pull/127161
>From 17b1184b8fadc851d4040845066b4d53f7700b98 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 | 20 +++++++++++++--- clang/test/Modules/safe_buffers_optout.cpp | 28 +++++++--------------- 2 files changed, 25 insertions(+), 23 deletions(-) diff --git a/clang/lib/Sema/AnalysisBasedWarnings.cpp b/clang/lib/Sema/AnalysisBasedWarnings.cpp index 589869d018657..fd46d97fec613 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 Module *const TUModule; public: - CallableVisitor(llvm::function_ref<void(const Decl *)> Callback) - : Callback(Callback) { + CallableVisitor(llvm::function_ref<void(const Decl *)> Callback, + const Module *const TUModule) + : Callback(Callback), TUModule(TUModule) { 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 && Node->getOwningModule() == TUModule) { + 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 +2646,8 @@ 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->getOwningModule()) + .TraverseTranslationUnitDecl(TU); } } diff --git a/clang/test/Modules/safe_buffers_optout.cpp b/clang/test/Modules/safe_buffers_optout.cpp index 2129db65da752..8c3d6a235d399 100644 --- a/clang/test/Modules/safe_buffers_optout.cpp +++ b/clang/test/Modules/safe_buffers_optout.cpp @@ -95,18 +95,10 @@ int textual(int *p) { // `safe_buffers_test_optout`, which uses another top-level module // `safe_buffers_test_base`. (So the module dependencies form a DAG.) -// No expected warnings from base.h because base.h is a separate -// module and in a separate TU that is not textually included. The -// explicit command that builds base.h has no `-Wunsafe-buffer-usage`. - -// expected-warning@base.h:3{{unsafe buffer access}} -// expected-note@base.h:3{{pass -fsafe-buffer-usage-suggestions to receive code hardening suggestions}} -// expected-warning@test_sub1.h:5{{unsafe buffer access}} -// expected-note@test_sub1.h:5{{pass -fsafe-buffer-usage-suggestions to receive code hardening suggestions}} -// expected-warning@test_sub1.h:14{{unsafe buffer access}} -// expected-note@test_sub1.h:14{{pass -fsafe-buffer-usage-suggestions to receive code hardening suggestions}} -// expected-warning@test_sub2.h:5{{unsafe buffer access}} -// expected-note@test_sub2.h:5{{pass -fsafe-buffer-usage-suggestions to receive code hardening suggestions}} +// No expected warnings from base.h, test_sub1, or test_sub2 because they are +// in seperate modules, and the explicit commands that builds them have no +// `-Wunsafe-buffer-usage`. + int foo(int * p) { int x = p[5]; // expected-warning{{unsafe buffer access}} expected-note{{pass -fsafe-buffer-usage-suggestions to receive code hardening suggestions}} #pragma clang unsafe_buffer_usage begin @@ -129,14 +121,10 @@ int foo(int * p) { // `safe_buffers_test_optout`, which uses another top-level module // `safe_buffers_test_base`. (So the module dependencies form a DAG.) -// expected-warning@base.h:3{{unsafe buffer access}} -// expected-note@base.h:3{{pass -fsafe-buffer-usage-suggestions to receive code hardening suggestions}} -// expected-warning@test_sub1.h:5{{unsafe buffer access}} -// expected-note@test_sub1.h:5{{pass -fsafe-buffer-usage-suggestions to receive code hardening suggestions}} -// expected-warning@test_sub1.h:14{{unsafe buffer access}} -// expected-note@test_sub1.h:14{{pass -fsafe-buffer-usage-suggestions to receive code hardening suggestions}} -// expected-warning@test_sub2.h:5{{unsafe buffer access}} -// expected-note@test_sub2.h:5{{pass -fsafe-buffer-usage-suggestions to receive code hardening suggestions}} +// No expected warnings from base.h, test_sub1, or test_sub2 because they are +// in seperate modules, and the explicit commands that builds them have no +// `-Wunsafe-buffer-usage`. + int foo(int * p) { int x = p[5]; // expected-warning{{unsafe buffer access}} expected-note{{pass -fsafe-buffer-usage-suggestions to receive code hardening suggestions}} #pragma clang unsafe_buffer_usage begin _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
