https://github.com/spavloff updated https://github.com/llvm/llvm-project/pull/131649
>From cdf9f1a5b960d2561a7c4415313b397578de0f8b Mon Sep 17 00:00:00 2001 From: Serge Pavlov <sepavl...@gmail.com> Date: Mon, 17 Mar 2025 21:33:24 +0700 Subject: [PATCH 1/2] [clang] Fix array types comparison in getCommonSugaredType Const-qualification of an array caused by constexpr specifier can produce QualType, where the const qualifier is set both as fast qualifier and as a qualifier of the array element type. It can result in a compiler crash, because such QualType does not compare equal to the same type but without extra qualification. To avoid the crash, the redundant qualifiers are removed while searching for common sugar. It fixes https://github.com/llvm/llvm-project/issues/97005 (Clang crashed in ASTContext::getCommonSugaredType). --- clang/lib/AST/ASTContext.cpp | 9 +++++++++ clang/test/SemaCXX/constexpr-implicit-const-97005.cpp | 10 ++++++++++ 2 files changed, 19 insertions(+) create mode 100644 clang/test/SemaCXX/constexpr-implicit-const-97005.cpp diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp index 7ed5b033d9bd8..2614c4235c994 100644 --- a/clang/lib/AST/ASTContext.cpp +++ b/clang/lib/AST/ASTContext.cpp @@ -14171,6 +14171,15 @@ static QualType getCommonSugarTypeNode(ASTContext &Ctx, const Type *X, static auto unwrapSugar(SplitQualType &T, Qualifiers &QTotal) { SmallVector<SplitQualType, 8> R; while (true) { + if (const auto *ATy = dyn_cast<ArrayType>(T.Ty)) { + // C++ 9.3.3.4p3: Any type of the form "cv-qualifier-seq array of N U" is + // adjusted to "array of N cv-qualifier-seq U". + // C23 6.7.3p10: If the specification of an array type includes any type + // qualifiers, both the array and the element type are so-qualified. + // + // To simplify comparison remove the redundant qualifiers from the array. + T.Quals.removeCVRQualifiers(Qualifiers::Const | Qualifiers::Volatile); + } QTotal.addConsistentQualifiers(T.Quals); QualType NT = T.Ty->getLocallyUnqualifiedSingleStepDesugaredType(); if (NT == QualType(T.Ty, 0)) diff --git a/clang/test/SemaCXX/constexpr-implicit-const-97005.cpp b/clang/test/SemaCXX/constexpr-implicit-const-97005.cpp new file mode 100644 index 0000000000000..db6106998d02b --- /dev/null +++ b/clang/test/SemaCXX/constexpr-implicit-const-97005.cpp @@ -0,0 +1,10 @@ +// RUN: %clang_cc1 -triple x86_64-linux-gnu %s + +bool a; +constexpr const unsigned char c[] = { 5 }; +constexpr const unsigned char d[1] = { 0 }; +auto b = (a ? d : c); + +constexpr const unsigned char c1[][1] = {{ 5 }}; +constexpr const unsigned char d1[1][1] = {{ 0 }}; +auto b1 = (a ? d1 : c1); >From 9bc13aee5775af148941826b74e5c9fbaab907c7 Mon Sep 17 00:00:00 2001 From: Serge Pavlov <sepavl...@gmail.com> Date: Wed, 19 Mar 2025 23:50:19 +0700 Subject: [PATCH 2/2] Address review comments - Now only qualifiers that are found in array element are cleared, - Test are moved into a new location. --- clang/lib/AST/ASTContext.cpp | 39 ++++++++++++++----- .../constexpr-implicit-const-97005.cpp | 10 ----- clang/test/SemaCXX/sugar-common-types.cpp | 10 +++++ 3 files changed, 40 insertions(+), 19 deletions(-) delete mode 100644 clang/test/SemaCXX/constexpr-implicit-const-97005.cpp diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp index 2614c4235c994..28f43321622e9 100644 --- a/clang/lib/AST/ASTContext.cpp +++ b/clang/lib/AST/ASTContext.cpp @@ -14168,18 +14168,39 @@ static QualType getCommonSugarTypeNode(ASTContext &Ctx, const Type *X, llvm_unreachable("Unhandled Type Class"); } +/// Returns element type of the array, probably multidimensional, specified by +/// the given ArrayType. +/// \returns Canonical type of the array element. +static QualType getNonArrayElementType(const ArrayType* ATy) { + QualType ElTy = ATy->getElementType().getCanonicalType(); + while (auto *SubArr = dyn_cast<ArrayType>(ElTy.getTypePtr())) + ElTy = SubArr->getElementType(); + return ElTy; +} + +/// Given a qualified type, returns an equivalent type, which has cv-qualifiers +/// only at array element type. +static SplitQualType normalizeArrayQualifiers(const SplitQualType &T) { + if (const auto *ATy = dyn_cast<ArrayType>(T.Ty)) { + // C++ 9.3.3.4p3: Any type of the form "cv-qualifier-seq array of N U" is + // adjusted to "array of N cv-qualifier-seq U". + // C23 6.7.3p10: If the specification of an array type includes any type + // qualifiers, both the array and the element type are so-qualified. + // + // If cv-qualifier is present in both array and element type, remove the + // redundant qualifiers from the array. + QualType ElTy = getNonArrayElementType(ATy); + unsigned Quals = + ElTy.getCVRQualifiers() & (Qualifiers::Const | Qualifiers::Volatile); + return SplitQualType(ATy, Qualifiers::fromCVRMask(Quals)); + } + return T; +} + static auto unwrapSugar(SplitQualType &T, Qualifiers &QTotal) { SmallVector<SplitQualType, 8> R; while (true) { - if (const auto *ATy = dyn_cast<ArrayType>(T.Ty)) { - // C++ 9.3.3.4p3: Any type of the form "cv-qualifier-seq array of N U" is - // adjusted to "array of N cv-qualifier-seq U". - // C23 6.7.3p10: If the specification of an array type includes any type - // qualifiers, both the array and the element type are so-qualified. - // - // To simplify comparison remove the redundant qualifiers from the array. - T.Quals.removeCVRQualifiers(Qualifiers::Const | Qualifiers::Volatile); - } + T = normalizeArrayQualifiers(T); QTotal.addConsistentQualifiers(T.Quals); QualType NT = T.Ty->getLocallyUnqualifiedSingleStepDesugaredType(); if (NT == QualType(T.Ty, 0)) diff --git a/clang/test/SemaCXX/constexpr-implicit-const-97005.cpp b/clang/test/SemaCXX/constexpr-implicit-const-97005.cpp deleted file mode 100644 index db6106998d02b..0000000000000 --- a/clang/test/SemaCXX/constexpr-implicit-const-97005.cpp +++ /dev/null @@ -1,10 +0,0 @@ -// RUN: %clang_cc1 -triple x86_64-linux-gnu %s - -bool a; -constexpr const unsigned char c[] = { 5 }; -constexpr const unsigned char d[1] = { 0 }; -auto b = (a ? d : c); - -constexpr const unsigned char c1[][1] = {{ 5 }}; -constexpr const unsigned char d1[1][1] = {{ 0 }}; -auto b1 = (a ? d1 : c1); diff --git a/clang/test/SemaCXX/sugar-common-types.cpp b/clang/test/SemaCXX/sugar-common-types.cpp index 39a762127811f..a1843df90640e 100644 --- a/clang/test/SemaCXX/sugar-common-types.cpp +++ b/clang/test/SemaCXX/sugar-common-types.cpp @@ -146,3 +146,13 @@ namespace GH67603 { } template void h<int>(); } // namespace GH67603 + +namespace PR97005 { + bool a; + constexpr const unsigned char c[] = { 5 }; + constexpr const unsigned char d[1] = { 0 }; + auto b = (a ? d : c); + constexpr const unsigned char c1[][1] = {{ 5 }}; + constexpr const unsigned char d1[1][1] = {{ 0 }}; + auto b1 = (a ? d1 : c1); +} // namespace PR97005 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
