[clang] [Clang][Sema] Fix incorrect rejection default construction of union with nontrivial member (PR #82407)
Shafik Yaghmour via cfe-commits
cfe-commits at lists.llvm.org
Thu Feb 29 19:09:19 PST 2024
https://github.com/shafik updated https://github.com/llvm/llvm-project/pull/82407
>From 5fcaeaddccc0f7e370bf7bebce113d8d52e1b1bd Mon Sep 17 00:00:00 2001
From: Shafik Yaghmour <shafik.yaghmour at intel.com>
Date: Tue, 20 Feb 2024 11:22:39 -0800
Subject: [PATCH] [Clang][Sema] Fix incorrect rejection default construction of
union with nontrivial member
In 765d8a192180f8f33618087b15c022fe758044af we impelemented a fix for incorrect deletion of
default constructors in unions. This fix missed a case and so this PR will
extend the fix to cover the additional case.
Fixes: https://github.com/llvm/llvm-project/issues/81774
---
clang/docs/ReleaseNotes.rst | 3 +++
clang/lib/Sema/SemaDeclCXX.cpp | 18 +++++++++++++++---
.../test/CodeGen/union-non-trivial-member.cpp | 17 +++++++++++++++++
clang/test/SemaCXX/cxx0x-nontrivial-union.cpp | 11 +++++++++++
4 files changed, 46 insertions(+), 3 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 5bca2c965c866b..452382eb6c4a1e 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -292,6 +292,9 @@ Bug Fixes to C++ Support
was only accepted at namespace scope but not at local function scope.
- Clang no longer tries to call consteval constructors at runtime when they appear in a member initializer.
(`#782154 <https://github.com/llvm/llvm-project/issues/82154>`_`)
+- Fix for clang incorrectly rejecting the default construction of a union with
+ nontrivial member when another member has an initializer.
+ (`#81774 <https://github.com/llvm/llvm-project/issues/81774>`_)
Bug Fixes to AST Handling
^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 79263bc3ff671d..25a4b4381ca25e 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -9442,9 +9442,21 @@ bool SpecialMemberDeletionInfo::shouldDeleteForSubobjectCall(
int DiagKind = -1;
- if (SMOR.getKind() == Sema::SpecialMemberOverloadResult::NoMemberOrDeleted)
- DiagKind = !Decl ? 0 : 1;
- else if (SMOR.getKind() == Sema::SpecialMemberOverloadResult::Ambiguous)
+ if (SMOR.getKind() == Sema::SpecialMemberOverloadResult::NoMemberOrDeleted) {
+ if (CSM == Sema::CXXDefaultConstructor && Field &&
+ Field->getParent()->isUnion()) {
+ // [class.default.ctor]p2:
+ // A defaulted default constructor for class X is defined as deleted if
+ // - X is a union that has a variant member with a non-trivial default
+ // constructor and no variant member of X has a default member
+ // initializer
+ const auto *RD = cast<CXXRecordDecl>(Field->getParent());
+ if (!RD->hasInClassInitializer())
+ DiagKind = !Decl ? 0 : 1;
+ } else {
+ DiagKind = !Decl ? 0 : 1;
+ }
+ } else if (SMOR.getKind() == Sema::SpecialMemberOverloadResult::Ambiguous)
DiagKind = 2;
else if (!isAccessible(Subobj, Decl))
DiagKind = 3;
diff --git a/clang/test/CodeGen/union-non-trivial-member.cpp b/clang/test/CodeGen/union-non-trivial-member.cpp
index fdc9fd16911e14..8b055a9970fc75 100644
--- a/clang/test/CodeGen/union-non-trivial-member.cpp
+++ b/clang/test/CodeGen/union-non-trivial-member.cpp
@@ -15,14 +15,25 @@ union UnionNonTrivial {
non_trivial_constructor b{};
};
+struct Handle {
+ Handle(int) {}
+};
+
+union UnionNonTrivialEqualInit {
+ int NoState = 0;
+ Handle CustomState;
+};
+
void f() {
UnionInt u1;
UnionNonTrivial u2;
+ UnionNonTrivialEqualInit u3;
}
// CHECK: define dso_local void @_Z1fv()
// CHECK: call void @_ZN8UnionIntC1Ev
// CHECK-NEXT: call void @_ZN15UnionNonTrivialC1Ev
+// CHECK-NEXT: call void @_ZN24UnionNonTrivialEqualInitC1Ev
// CHECK: define {{.*}}void @_ZN8UnionIntC1Ev
// CHECK: call void @_ZN8UnionIntC2Ev
@@ -30,8 +41,14 @@ void f() {
// CHECK: define {{.*}}void @_ZN15UnionNonTrivialC1Ev
// CHECK: call void @_ZN15UnionNonTrivialC2Ev
+// CHECK: define {{.*}}void @_ZN24UnionNonTrivialEqualInitC1Ev
+// CHECK: call void @_ZN24UnionNonTrivialEqualInitC2Ev
+
// CHECK: define {{.*}}void @_ZN8UnionIntC2Ev
// CHECK: store i32 1000
// CHECK: define {{.*}}void @_ZN15UnionNonTrivialC2Ev
// CHECK: call void @_ZN23non_trivial_constructorC1Ev
+
+// CHECK: define {{.*}}void @_ZN24UnionNonTrivialEqualInitC2Ev
+// CHECK: store i32 0
diff --git a/clang/test/SemaCXX/cxx0x-nontrivial-union.cpp b/clang/test/SemaCXX/cxx0x-nontrivial-union.cpp
index c7cdf76d850dbe..833642b3d739ab 100644
--- a/clang/test/SemaCXX/cxx0x-nontrivial-union.cpp
+++ b/clang/test/SemaCXX/cxx0x-nontrivial-union.cpp
@@ -188,3 +188,14 @@ static_assert(U2().b.x == 100, "");
static_assert(U3().b.x == 100, "");
} // namespace GH48416
+
+namespace GH81774 {
+struct Handle {
+ Handle(int) {}
+};
+// Should be well-formed because NoState has a brace-or-equal-initializer.
+union a {
+ int NoState = 0;
+ Handle CustomState;
+} b;
+} // namespace GH81774
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