llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang Author: Vincent (Mr-Anyone) <details> <summary>Changes</summary> Check for missing VLA size expressions (e.g. in int a[*][10]) before evaluation to avoid crashes in _Countof and constant expression checks. fixes #<!-- -->152826 --- Full diff: https://github.com/llvm/llvm-project/pull/154627.diff 4 Files Affected: - (modified) clang/docs/ReleaseNotes.rst (+2) - (modified) clang/lib/AST/ByteCode/Compiler.cpp (+3-1) - (modified) clang/lib/AST/ExprConstant.cpp (+11-1) - (added) clang/test/Sema/gh152826.c (+6) ``````````diff diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index e88d68fa99664..df738db771e33 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -200,6 +200,8 @@ Bug Fixes in This Version ------------------------- - Fix a crash when marco name is empty in ``#pragma push_macro("")`` or ``#pragma pop_macro("")``. (#GH149762). +- Fix a crash in variable length array (e.g. int a[*]) function parameter type + being used in `_Countof` expression. (#GH152826) - `-Wunreachable-code`` now diagnoses tautological or contradictory comparisons such as ``x != 0 || x != 1.0`` and ``x == 0 && x == 1.0`` on targets that treat ``_Float16``/``__fp16`` as native scalar types. Previously diff --git a/clang/lib/AST/ByteCode/Compiler.cpp b/clang/lib/AST/ByteCode/Compiler.cpp index e3235d34e230e..7881afc4bb6f5 100644 --- a/clang/lib/AST/ByteCode/Compiler.cpp +++ b/clang/lib/AST/ByteCode/Compiler.cpp @@ -2248,7 +2248,9 @@ bool Compiler<Emitter>::VisitUnaryExprOrTypeTraitExpr( assert(VAT); if (VAT->getElementType()->isArrayType()) { std::optional<APSInt> Res = - VAT->getSizeExpr()->getIntegerConstantExpr(ASTCtx); + VAT->getSizeExpr() + ? VAT->getSizeExpr()->getIntegerConstantExpr(ASTCtx) + : std::nullopt; if (Res) { if (DiscardResult) return true; diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp index 9c87a88899647..1d939cf9655d4 100644 --- a/clang/lib/AST/ExprConstant.cpp +++ b/clang/lib/AST/ExprConstant.cpp @@ -15345,6 +15345,13 @@ bool IntExprEvaluator::VisitUnaryExprOrTypeTraitExpr( const auto *VAT = Info.Ctx.getAsVariableArrayType(Ty); assert(VAT); if (VAT->getElementType()->isArrayType()) { + // Variable array size expression could be missing (e.g. int a[*][10]) In + // that case, it can't be a constant expression + if (!VAT->getSizeExpr()) { + Info.FFDiag(E->getBeginLoc()); + return false; + } + std::optional<APSInt> Res = VAT->getSizeExpr()->getIntegerConstantExpr(Info.Ctx); if (Res) { @@ -17867,7 +17874,10 @@ static ICEDiag CheckICE(const Expr* E, const ASTContext &Ctx) { // it is an ICE or not. const auto *VAT = Ctx.getAsVariableArrayType(ArgTy); if (VAT->getElementType()->isArrayType()) - return CheckICE(VAT->getSizeExpr(), Ctx); + // Variable array size expression could be missing (e.g. int a[*][10]) + // In that case, it can't be a constant expression + return VAT->getSizeExpr() ? CheckICE(VAT->getSizeExpr(), Ctx) + : ICEDiag(IK_NotICE, E->getBeginLoc()); // Otherwise, this is a regular VLA, which is definitely not an ICE. return ICEDiag(IK_NotICE, E->getBeginLoc()); diff --git a/clang/test/Sema/gh152826.c b/clang/test/Sema/gh152826.c new file mode 100644 index 0000000000000..a7d5f0138ad5d --- /dev/null +++ b/clang/test/Sema/gh152826.c @@ -0,0 +1,6 @@ +// RUN: %clang_cc1 -std=c2y -verify %s +// RUN: %clang_cc1 -std=c2y -verify -fexperimental-new-constant-interpreter %s +// expected-no-diagnostics + +void gh152826(char (*a)[*][5], int (*x)[_Countof (*a)]); +void more_likely_in_practice(unsigned long size_one, int (*a)[*][5], int b[_Countof(*a)]); `````````` </details> https://github.com/llvm/llvm-project/pull/154627 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
