https://github.com/shashi1687 updated https://github.com/llvm/llvm-project/pull/147213
>From 05211dac479bf25aaf6d8ecc3a53871a51f7ffdd Mon Sep 17 00:00:00 2001 From: Shashi Shankar <shashishankar1...@gmail.com> Date: Sun, 6 Jul 2025 22:25:48 +0200 Subject: [PATCH 1/3] Sema: filter out invalid base-specifiers before attaching ActOnBaseSpecifiers now skips nullptr entries returned for invalid bases, avoiding ICE on invalid inheritance. Added regression test in SemaCXX/invalid-inheritance.cpp. Fixes #147186 Signed-off-by: Shashi Shankar <shashishankar1...@gmail.com> --- clang/lib/Sema/SemaDeclCXX.cpp | 17 ++++++++++++++++- clang/test/SemaCXX/invalid-base-inheritance.cpp | 13 +++++++++++++ 2 files changed, 29 insertions(+), 1 deletion(-) create mode 100644 clang/test/SemaCXX/invalid-base-inheritance.cpp diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp index f0247f865ba40..231610241d8ee 100644 --- a/clang/lib/Sema/SemaDeclCXX.cpp +++ b/clang/lib/Sema/SemaDeclCXX.cpp @@ -3031,8 +3031,23 @@ void Sema::ActOnBaseSpecifiers(Decl *ClassDecl, if (!ClassDecl || Bases.empty()) return; + // --- drop any bases already diagnosed invalid --- + SmallVector<CXXBaseSpecifier *, 4> ValidBases; + ValidBases.reserve(Bases.size()); + for (auto *BS : Bases) + if (BS) + ValidBases.push_back(BS); + if (ValidBases.empty()) + return; + + if (ValidBases.empty()) + return; // nothing valid to attach + AdjustDeclIfTemplate(ClassDecl); - AttachBaseSpecifiers(cast<CXXRecordDecl>(ClassDecl), Bases); + // Attach only the valid bases so downstream never ICEs + AttachBaseSpecifiers(cast<CXXRecordDecl>(ClassDecl), + llvm::MutableArrayRef<CXXBaseSpecifier *>( + ValidBases.data(), ValidBases.size())); } bool Sema::IsDerivedFrom(SourceLocation Loc, CXXRecordDecl *Derived, diff --git a/clang/test/SemaCXX/invalid-base-inheritance.cpp b/clang/test/SemaCXX/invalid-base-inheritance.cpp new file mode 100644 index 0000000000000..21b3eb57ef914 --- /dev/null +++ b/clang/test/SemaCXX/invalid-base-inheritance.cpp @@ -0,0 +1,13 @@ +// Tests that invalid base-specifiers no longer crash the compiler. +// RUN: %clang_cc1 -std=c++20 -fsyntax-only -verify %s + +class X; // expected-note {{forward declaration of 'X'}} expected-note {{forward declaration of 'X'}} + +class A : X { // expected-error {{base class has incomplete type}} +}; + +class Y : int { // expected-error {{expected class name}} +}; + +class Z : X*, virtual int { // expected-error {{base class has incomplete type}} expected-error {{expected class name}} +}; >From 53984191e3e45d3964f6ff71d70df7c030659369 Mon Sep 17 00:00:00 2001 From: Shashi Shankar <shashishankar1...@gmail.com> Date: Wed, 9 Jul 2025 00:10:51 +0200 Subject: [PATCH 2/3] ParseDeclCXX: reject unusable base classes via isUsableType In Parser::ParseBaseSpecifier, replace the previous `isInvalid` check with `!BaseTy->isUsableType()` so that we early-reject any non-instantiable class/struct/union as a base. Add a one-line entry to clang/docs/ReleaseNotes.rst. Fixes #147213. --- clang/docs/ReleaseNotes.rst | 1 + clang/lib/Parse/ParseDeclCXX.cpp | 5 ++++- clang/lib/Sema/SemaDeclCXX.cpp | 17 +---------------- 3 files changed, 6 insertions(+), 17 deletions(-) diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index a919f3a71c9cf..141391a164814 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -920,6 +920,7 @@ Bug Fixes to C++ Support - Correctly handle allocations in the condition of a ``if constexpr``.(#GH120197) (#GH134820) - Fixed a crash when handling invalid member using-declaration in C++20+ mode. (#GH63254) - Fix a crash when trying to instantiate an ambiguous specialization. (#GH51866) +- Switch `ParseBaseClause` to use `BaseResult::isUsable()` instead of `isInvalid()`, fixing dropped or mis-parsed base specifiers in C++ classes. (#GH147186) Bug Fixes to AST Handling ^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp index eae8281964692..e7bb5b48058d0 100644 --- a/clang/lib/Parse/ParseDeclCXX.cpp +++ b/clang/lib/Parse/ParseDeclCXX.cpp @@ -2252,7 +2252,10 @@ void Parser::ParseBaseClause(Decl *ClassDecl) { while (true) { // Parse a base-specifier. BaseResult Result = ParseBaseSpecifier(ClassDecl); - if (Result.isInvalid()) { + // Skip any base-specifier we couldn’t actually build into a usable + // CXXBaseSpecifier (covers both syntactic invalidity and + // other un-usable cases). + if (!Result.isUsable()) { // Skip the rest of this base specifier, up until the comma or // opening brace. SkipUntil(tok::comma, tok::l_brace, StopAtSemi | StopBeforeMatch); diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp index 231610241d8ee..f0247f865ba40 100644 --- a/clang/lib/Sema/SemaDeclCXX.cpp +++ b/clang/lib/Sema/SemaDeclCXX.cpp @@ -3031,23 +3031,8 @@ void Sema::ActOnBaseSpecifiers(Decl *ClassDecl, if (!ClassDecl || Bases.empty()) return; - // --- drop any bases already diagnosed invalid --- - SmallVector<CXXBaseSpecifier *, 4> ValidBases; - ValidBases.reserve(Bases.size()); - for (auto *BS : Bases) - if (BS) - ValidBases.push_back(BS); - if (ValidBases.empty()) - return; - - if (ValidBases.empty()) - return; // nothing valid to attach - AdjustDeclIfTemplate(ClassDecl); - // Attach only the valid bases so downstream never ICEs - AttachBaseSpecifiers(cast<CXXRecordDecl>(ClassDecl), - llvm::MutableArrayRef<CXXBaseSpecifier *>( - ValidBases.data(), ValidBases.size())); + AttachBaseSpecifiers(cast<CXXRecordDecl>(ClassDecl), Bases); } bool Sema::IsDerivedFrom(SourceLocation Loc, CXXRecordDecl *Derived, >From 2ba0f19d4c15b5de0e000762276801bca985ef4b Mon Sep 17 00:00:00 2001 From: Shashi Shankar <shashishankar1...@gmail.com> Date: Wed, 9 Jul 2025 08:56:43 +0200 Subject: [PATCH 3/3] Apply suggestions from code review Adding review comment Co-authored-by: Corentin Jabot <corentinja...@gmail.com> --- clang/docs/ReleaseNotes.rst | 2 +- clang/lib/Parse/ParseDeclCXX.cpp | 3 --- clang/test/SemaCXX/invalid-base-inheritance.cpp | 3 +++ 3 files changed, 4 insertions(+), 4 deletions(-) diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index e6913f298ce5e..09ab62df9d09f 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -923,7 +923,7 @@ Bug Fixes to C++ Support - Improved handling of variables with ``consteval`` constructors, to consistently treat the initializer as manifestly constant-evaluated. (#GH135281) -- Switch `ParseBaseClause` to use `BaseResult::isUsable()` instead of `isInvalid()`, fixing dropped or mis-parsed base specifiers in C++ classes. (#GH147186) +- Fix a crash in the presence of invalid base classes. (#GH147186) Bug Fixes to AST Handling ^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp index e7bb5b48058d0..59e6e0af4b5b0 100644 --- a/clang/lib/Parse/ParseDeclCXX.cpp +++ b/clang/lib/Parse/ParseDeclCXX.cpp @@ -2252,9 +2252,6 @@ void Parser::ParseBaseClause(Decl *ClassDecl) { while (true) { // Parse a base-specifier. BaseResult Result = ParseBaseSpecifier(ClassDecl); - // Skip any base-specifier we couldn’t actually build into a usable - // CXXBaseSpecifier (covers both syntactic invalidity and - // other un-usable cases). if (!Result.isUsable()) { // Skip the rest of this base specifier, up until the comma or // opening brace. diff --git a/clang/test/SemaCXX/invalid-base-inheritance.cpp b/clang/test/SemaCXX/invalid-base-inheritance.cpp index 21b3eb57ef914..1cfb8fe6f0246 100644 --- a/clang/test/SemaCXX/invalid-base-inheritance.cpp +++ b/clang/test/SemaCXX/invalid-base-inheritance.cpp @@ -1,6 +1,8 @@ // Tests that invalid base-specifiers no longer crash the compiler. // RUN: %clang_cc1 -std=c++20 -fsyntax-only -verify %s +namespace GH147186 { + class X; // expected-note {{forward declaration of 'X'}} expected-note {{forward declaration of 'X'}} class A : X { // expected-error {{base class has incomplete type}} @@ -11,3 +13,4 @@ class Y : int { // expected-error {{expected class name}} class Z : X*, virtual int { // expected-error {{base class has incomplete type}} expected-error {{expected class name}} }; +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits