rnk created this revision.
rnk added a reviewer: rsmith.
Herald added a project: clang.
DONOTSUBMIT: Uploading for feedback on approach, still have test failures:
********************
Failing Tests (1):
Clang :: CXX/class.access/p4.cpp
In the MS C++ ABI, complete destructors for classes with virtual bases
are emitted whereever they are needed. The complete destructor calls:
- the base dtor
- for each vbase, its base dtor
Even when a destructor is user-defined in another TU, clang needs to
mark the virtual base dtors referenced in TUs that call destructors.
This fixes PR38521.
FIXME: What about separating base and complete dtors? i.e. what about
when only base dtors are ref'd?
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D77081
Files:
clang/include/clang/Sema/Sema.h
clang/lib/Sema/SemaDeclCXX.cpp
clang/lib/Sema/SemaExpr.cpp
Index: clang/lib/Sema/SemaExpr.cpp
===================================================================
--- clang/lib/Sema/SemaExpr.cpp
+++ clang/lib/Sema/SemaExpr.cpp
@@ -15998,10 +15998,19 @@
} else if (CXXDestructorDecl *Destructor =
dyn_cast<CXXDestructorDecl>(Func)) {
Destructor = cast<CXXDestructorDecl>(Destructor->getFirstDecl());
- if (Destructor->isDefaulted() && !Destructor->isDeleted()) {
- if (Destructor->isTrivial() && !Destructor->hasAttr<DLLExportAttr>())
- return;
- DefineImplicitDestructor(Loc, Destructor);
+ if (!Destructor->isDeleted()) {
+ if (Destructor->isDefaulted()) {
+ if (Destructor->isTrivial() &&
+ !Destructor->hasAttr<DLLExportAttr>())
+ return;
+ DefineImplicitDestructor(Loc, Destructor);
+ } else if (Context.getTargetInfo().getCXXABI().isMicrosoft()) {
+ // In the MS ABI, the complete destructor is implicitly defined,
+ // even if the base destructor is user defined.
+ // FIXME: Need a way to do it only once. "setBody" seems wrong.
+ if (Destructor->getParent()->getNumVBases() > 0)
+ DefineImplicitCompleteDestructor(Loc, Destructor);
+ }
}
if (Destructor->isVirtual() && getLangOpts().AppleKext)
MarkVTableUsed(Loc, Destructor->getParent());
Index: clang/lib/Sema/SemaDeclCXX.cpp
===================================================================
--- clang/lib/Sema/SemaDeclCXX.cpp
+++ clang/lib/Sema/SemaDeclCXX.cpp
@@ -13202,6 +13202,53 @@
}
}
+void Sema::DefineImplicitCompleteDestructor(SourceLocation CurrentLocation,
+ CXXDestructorDecl *Destructor) {
+ if (Destructor->isInvalidDecl())
+ return;
+
+ CXXRecordDecl *ClassDecl = Destructor->getParent();
+ assert(Context.getTargetInfo().getCXXABI().isMicrosoft() &&
+ "implicit complete dtors unneeded outside MS ABI");
+ assert(ClassDecl->getNumVBases() > 0 &&
+ "complete dtor only exists for classes with vbases");
+
+ SynthesizedFunctionScope Scope(*this, Destructor);
+
+ // Add a context note for diagnostics produced after this point.
+ Scope.addContextNote(CurrentLocation);
+
+ // No need to resolve the exception specification of the base destructor or
+ // mark vtables referenced. That will be done when the base dtor is defined.
+
+ // Similar to what is done above in MarkBaseAndMemberDestructorsReferenced,
+ // but only for virtual bases.
+ for (const CXXBaseSpecifier &VBase : ClassDecl->vbases()) {
+ // Bases are always records in a well-formed non-dependent class.
+ CXXRecordDecl *BaseRD = VBase.getType()->getAsCXXRecordDecl();
+
+ // If our base class is invalid, we probably can't get its dtor anyway.
+ if (!BaseRD || BaseRD->isInvalidDecl() || BaseRD->hasIrrelevantDestructor())
+ continue;
+
+ CXXDestructorDecl *Dtor = LookupDestructor(BaseRD);
+ assert(Dtor && "No dtor found for BaseRD!");
+ if (CheckDestructorAccess(
+ ClassDecl->getLocation(), Dtor,
+ PDiag(diag::err_access_dtor_vbase)
+ << Context.getTypeDeclType(ClassDecl) << VBase.getType(),
+ Context.getTypeDeclType(ClassDecl)) == AR_accessible) {
+ CheckDerivedToBaseConversion(
+ Context.getTypeDeclType(ClassDecl), VBase.getType(),
+ diag::err_access_dtor_vbase, 0, ClassDecl->getLocation(),
+ SourceRange(), DeclarationName(), nullptr);
+ }
+
+ MarkFunctionReferenced(Dtor->getLocation(), Dtor);
+ DiagnoseUseOfDecl(Dtor, Dtor->getLocation());
+ }
+}
+
/// Perform any semantic analysis which needs to be delayed until all
/// pending class member declarations have been parsed.
void Sema::ActOnFinishCXXMemberDecls() {
Index: clang/include/clang/Sema/Sema.h
===================================================================
--- clang/include/clang/Sema/Sema.h
+++ clang/include/clang/Sema/Sema.h
@@ -5559,6 +5559,11 @@
void DefineImplicitDestructor(SourceLocation CurrentLocation,
CXXDestructorDecl *Destructor);
+ /// Define an implicit complete constructor for classes with vbases in the MS
+ /// ABI.
+ void DefineImplicitCompleteDestructor(SourceLocation CurrentLocation,
+ CXXDestructorDecl *Dtor);
+
/// Build an exception spec for destructors that don't have one.
///
/// C++11 says that user-defined destructors with no exception spec get one
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