Author: Mariya Podchishchaeva Date: 2024-11-15T09:26:14+01:00 New Revision: c9e8540d6c87ecd5a5057a9b0fe47d63affe3062
URL: https://github.com/llvm/llvm-project/commit/c9e8540d6c87ecd5a5057a9b0fe47d63affe3062 DIFF: https://github.com/llvm/llvm-project/commit/c9e8540d6c87ecd5a5057a9b0fe47d63affe3062.diff LOG: [clang] Fix C23 constexpr crashes (#112708) Before using a constexpr variable that is not properly initialized check that it is valid. Fixes https://github.com/llvm/llvm-project/issues/109095 Fixes https://github.com/llvm/llvm-project/issues/112516 Added: Modified: clang/lib/AST/Decl.cpp clang/test/Sema/constexpr.c Removed: ################################################################################ diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp index 490c4a2fc525cd..bc7cce0bcd7fc2 100644 --- a/clang/lib/AST/Decl.cpp +++ b/clang/lib/AST/Decl.cpp @@ -2503,7 +2503,8 @@ bool VarDecl::isUsableInConstantExpressions(const ASTContext &Context) const { if (!DefVD->mightBeUsableInConstantExpressions(Context)) return false; // ... and its initializer is a constant initializer. - if (Context.getLangOpts().CPlusPlus && !DefVD->hasConstantInitialization()) + if ((Context.getLangOpts().CPlusPlus || getLangOpts().C23) && + !DefVD->hasConstantInitialization()) return false; // C++98 [expr.const]p1: // An integral constant-expression can involve only [...] const variables @@ -2610,8 +2611,11 @@ bool VarDecl::hasICEInitializer(const ASTContext &Context) const { } bool VarDecl::hasConstantInitialization() const { - // In C, all globals (and only globals) have constant initialization. - if (hasGlobalStorage() && !getASTContext().getLangOpts().CPlusPlus) + // In C, all globals and constexpr variables should have constant + // initialization. For constexpr variables in C check that initializer is a + // constant initializer because they can be used in constant expressions. + if (hasGlobalStorage() && !getASTContext().getLangOpts().CPlusPlus && + !isConstexpr()) return true; // In C++, it depends on whether the evaluation at the point of definition diff --git a/clang/test/Sema/constexpr.c b/clang/test/Sema/constexpr.c index a874fd64808404..ad2c2ba98a1e3f 100644 --- a/clang/test/Sema/constexpr.c +++ b/clang/test/Sema/constexpr.c @@ -364,3 +364,20 @@ void constexprif() { void constevalif() { if consteval (300) {} //expected-error {{expected '(' after 'if'}} } + +struct S11 { + int len; +}; +void ghissue112516() { + struct S11 *s11 = 0; + constexpr int num = s11->len; // expected-error {{constexpr variable 'num' must be initialized by a constant expression}} + void *Arr[num]; +} + +void ghissue109095() { + constexpr char c[] = { 'a' }; + constexpr int i = c[1]; // expected-error {{constexpr variable 'i' must be initialized by a constant expression}}\ + // expected-note {{declared here}} + _Static_assert(i == c[0]); // expected-error {{static assertion expression is not an integral constant expression}}\ + // expected-note {{initializer of 'i' is not a constant expression}} +} _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
