This revision was automatically updated to reflect the committed changes.
ahatanak marked 2 inline comments as done.
Closed by commit rL353459: [Sema][ObjC] Disallow non-trivial C struct fields in
unions. (authored by ahatanak, committed by ).
Herald added a project: LLVM.
Herald added a subscriber: llvm-commits.
Changed prior to commit:
https://reviews.llvm.org/D55659?vs=185466&id=185846#toc
Repository:
rL LLVM
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D55659/new/
https://reviews.llvm.org/D55659
Files:
cfe/trunk/include/clang/AST/Type.h
cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
cfe/trunk/lib/AST/Type.cpp
cfe/trunk/lib/Sema/SemaDecl.cpp
cfe/trunk/test/SemaObjC/arc-decls.m
Index: cfe/trunk/lib/AST/Type.cpp
===================================================================
--- cfe/trunk/lib/AST/Type.cpp
+++ cfe/trunk/lib/AST/Type.cpp
@@ -22,6 +22,7 @@
#include "clang/AST/DeclTemplate.h"
#include "clang/AST/Expr.h"
#include "clang/AST/NestedNameSpecifier.h"
+#include "clang/AST/NonTrivialTypeVisitor.h"
#include "clang/AST/PrettyPrinter.h"
#include "clang/AST/TemplateBase.h"
#include "clang/AST/TemplateName.h"
@@ -2244,6 +2245,62 @@
getObjCLifetime() != Qualifiers::OCL_Weak;
}
+namespace {
+// Helper class that determines whether this is a type that is non-trivial to
+// primitive copy or move, or is a struct type that has a field of such type.
+template <bool IsMove>
+struct IsNonTrivialCopyMoveVisitor
+ : CopiedTypeVisitor<IsNonTrivialCopyMoveVisitor<IsMove>, IsMove, bool> {
+ using Super =
+ CopiedTypeVisitor<IsNonTrivialCopyMoveVisitor<IsMove>, IsMove, bool>;
+ IsNonTrivialCopyMoveVisitor(const ASTContext &C) : Ctx(C) {}
+ void preVisit(QualType::PrimitiveCopyKind PCK, QualType QT) {}
+
+ bool visitWithKind(QualType::PrimitiveCopyKind PCK, QualType QT) {
+ if (const auto *AT = this->Ctx.getAsArrayType(QT))
+ return this->asDerived().visit(QualType(AT, 0));
+ return Super::visitWithKind(PCK, QT);
+ }
+
+ bool visitARCStrong(QualType QT) { return true; }
+ bool visitARCWeak(QualType QT) { return true; }
+ bool visitTrivial(QualType QT) { return false; }
+ // Volatile fields are considered trivial.
+ bool visitVolatileTrivial(QualType QT) { return false; }
+
+ bool visitStruct(QualType QT) {
+ const RecordDecl *RD = QT->castAs<RecordType>()->getDecl();
+ // We don't want to apply the C restriction in C++ because C++
+ // (1) can apply the restriction at a finer grain by banning copying or
+ // destroying the union, and
+ // (2) allows users to override these restrictions by declaring explicit
+ // constructors/etc, which we're not proposing to add to C.
+ if (isa<CXXRecordDecl>(RD))
+ return false;
+ for (const FieldDecl *FD : RD->fields())
+ if (this->asDerived().visit(FD->getType()))
+ return true;
+ return false;
+ }
+
+ const ASTContext &Ctx;
+};
+
+} // namespace
+
+bool QualType::isNonTrivialPrimitiveCType(const ASTContext &Ctx) const {
+ if (isNonTrivialToPrimitiveDefaultInitialize())
+ return true;
+ DestructionKind DK = isDestructedType();
+ if (DK != DK_none && DK != DK_cxx_destructor)
+ return true;
+ if (IsNonTrivialCopyMoveVisitor<false>(Ctx).visit(*this))
+ return true;
+ if (IsNonTrivialCopyMoveVisitor<true>(Ctx).visit(*this))
+ return true;
+ return false;
+}
+
QualType::PrimitiveDefaultInitializeKind
QualType::isNonTrivialToPrimitiveDefaultInitialize() const {
if (const auto *RT =
Index: cfe/trunk/lib/Sema/SemaDecl.cpp
===================================================================
--- cfe/trunk/lib/Sema/SemaDecl.cpp
+++ cfe/trunk/lib/Sema/SemaDecl.cpp
@@ -15916,6 +15916,10 @@
Record->setHasObjectMember(true);
if (Record && FDTTy->getDecl()->hasVolatileMember())
Record->setHasVolatileMember(true);
+ if (Record && Record->isUnion() &&
+ FD->getType().isNonTrivialPrimitiveCType(Context))
+ Diag(FD->getLocation(),
+ diag::err_nontrivial_primitive_type_in_union);
} else if (FDTy->isObjCObjectType()) {
/// A field cannot be an Objective-c object
Diag(FD->getLocation(), diag::err_statically_allocated_object)
Index: cfe/trunk/include/clang/AST/Type.h
===================================================================
--- cfe/trunk/include/clang/AST/Type.h
+++ cfe/trunk/include/clang/AST/Type.h
@@ -1121,6 +1121,12 @@
};
/// Check if this is a non-trivial type that would cause a C struct
+ /// transitively containing this type to be non-trivial. This function can be
+ /// used to determine whether a field of this type can be declared inside a C
+ /// union.
+ bool isNonTrivialPrimitiveCType(const ASTContext &Ctx) const;
+
+ /// Check if this is a non-trivial type that would cause a C struct
/// transitively containing this type to be non-trivial to copy and return the
/// kind.
PrimitiveCopyKind isNonTrivialToPrimitiveCopy() const;
Index: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
@@ -609,6 +609,8 @@
InGroup<NonTrivialMemaccess>;
def note_nontrivial_field : Note<
"field is non-trivial to %select{copy|default-initialize}0">;
+def err_nontrivial_primitive_type_in_union : Error<
+ "non-trivial C types are disallowed in union">;
def warn_dyn_class_memaccess : Warning<
"%select{destination for|source of|first operand of|second operand of}0 this "
"%1 call is a pointer to %select{|class containing a }2dynamic class %3; "
Index: cfe/trunk/test/SemaObjC/arc-decls.m
===================================================================
--- cfe/trunk/test/SemaObjC/arc-decls.m
+++ cfe/trunk/test/SemaObjC/arc-decls.m
@@ -3,13 +3,29 @@
// rdar://8843524
struct A {
- id x;
+ id x[4];
+ id y;
};
union u {
id u; // expected-error {{ARC forbids Objective-C objects in union}}
};
+union u_nontrivial_c {
+ struct A a; // expected-error {{non-trivial C types are disallowed in union}}
+};
+
+// Volatile fields are fine.
+struct C {
+ volatile int x[4];
+ volatile int y;
+};
+
+union u_trivial_c {
+ volatile int b;
+ struct C c;
+};
+
@interface I {
struct A a;
struct B {
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