https://github.com/tbaederr created https://github.com/llvm/llvm-project/pull/149835
See https://github.com/llvm/llvm-project/commit/faee39baa87e43f4b746dd77e479268391163658 >From 08399fdaa0468d9e272a9fdc49871d57a9691529 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbae...@redhat.com> Date: Mon, 21 Jul 2025 16:56:27 +0200 Subject: [PATCH] [clang][bytecode] Unions again --- clang/lib/AST/ByteCode/Compiler.cpp | 9 ++++- clang/test/AST/ByteCode/unions.cpp | 55 +++++++++++++++++++++++++++++ 2 files changed, 63 insertions(+), 1 deletion(-) diff --git a/clang/lib/AST/ByteCode/Compiler.cpp b/clang/lib/AST/ByteCode/Compiler.cpp index 952a43a0ecbcf..597ec68d854b3 100644 --- a/clang/lib/AST/ByteCode/Compiler.cpp +++ b/clang/lib/AST/ByteCode/Compiler.cpp @@ -25,11 +25,18 @@ using APSInt = llvm::APSInt; namespace clang { namespace interp { +static bool hasTrivialDefaultCtorParent(const FieldDecl *FD) { + assert(FD); + assert(FD->getParent()->isUnion()); + const auto *CXXRD = dyn_cast<CXXRecordDecl>(FD->getParent()); + return !CXXRD || CXXRD->hasTrivialDefaultConstructor(); +} + static bool refersToUnion(const Expr *E) { for (;;) { if (const auto *ME = dyn_cast<MemberExpr>(E)) { if (const auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl()); - FD && FD->getParent()->isUnion()) + FD && FD->getParent()->isUnion() && hasTrivialDefaultCtorParent(FD)) return true; E = ME->getBase(); continue; diff --git a/clang/test/AST/ByteCode/unions.cpp b/clang/test/AST/ByteCode/unions.cpp index 7cfd0d677a7b3..ae71776353cf0 100644 --- a/clang/test/AST/ByteCode/unions.cpp +++ b/clang/test/AST/ByteCode/unions.cpp @@ -861,6 +861,61 @@ namespace CopyCtorMutable { // both-note {{in call}} } + +namespace NonTrivialCtor { + struct A { int x = 1; constexpr int f() { return 1; } }; + struct B : A { int y = 1; constexpr int g() { return 2; } }; + struct C { + int x; + constexpr virtual int f() = 0; + }; + struct D : C { + int y; + constexpr virtual int f() override { return 3; } + }; + + union U { + int n; + B b; + D d; + }; + + consteval int test(int which) { + if (which == 0) {} + + U u{.n = 5}; + assert_active(u); + assert_active(u.n); + assert_inactive(u.b); + + switch (which) { + case 0: + u.b.x = 10; // both-note {{assignment to member 'b' of union with active member 'n'}} + return u.b.f(); + case 1: + u.b.y = 10; // both-note {{assignment to member 'b' of union with active member 'n'}} + return u.b.g(); + case 2: + u.d.x = 10; // both-note {{assignment to member 'd' of union with active member 'n'}} + return u.d.f(); + case 3: + u.d.y = 10; // both-note {{assignment to member 'd' of union with active member 'n'}} + return u.d.f(); + } + + return 1; + } + static_assert(test(0)); // both-error {{not an integral constant expression}} \ + // both-note {{in call}} + static_assert(test(1)); // both-error {{not an integral constant expression}} \ + // both-note {{in call}} + static_assert(test(2)); // both-error {{not an integral constant expression}} \ + // both-note {{in call}} + static_assert(test(3)); // both-error {{not an integral constant expression}} \ + // both-note {{in call}} + +} + #endif namespace AddressComparison { _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
