r262851 - Module Debugging: Fix a crash when emitting debug info for nested tag types

[Adrian Prantl via cfe-commits]

> On Mar 10, 2016, at 3:21 PM, David Blaikie <dblaikie at gmail.com> wrote:
> 
> OK, so the idea is that when you see that a tag definition, skip it if any parent is incomplete - because when the parent's definition is complete, you'll emit all its children anyway?

Yes. If there’s a more direct way top achieve this without walking the declcontext, that would be even better of course.

-- adrian
> 
> On Thu, Mar 10, 2016 at 8:19 AM, Adrian Prantl <aprantl at apple.com <mailto:aprantl at apple.com>> wrote:
> 
> > On Mar 9, 2016, at 5:22 PM, David Blaikie <dblaikie at gmail.com <mailto:dblaikie at gmail.com>> wrote:
> >
> > Is this bug only reachable with modules debug info?
> 
> Yes, it’s in ObjectFilePCHContainerOperations.cpp, which is only used while building a PCH or module with -gmodules.
> 
> > Could you describe the nature of the fix (not quite clear to me just by looking at it)
> 
> In the ASTConsumer callback for a finished TagDecl, we check whether the DeclContext is complete and only try to emit debug info for the Decl if the DeclContext is available.
> 
> -- adrian
> 
> >
> > On Mon, Mar 7, 2016 at 12:58 PM, Adrian Prantl via cfe-commits <cfe-commits at lists.llvm.org <mailto:cfe-commits at lists.llvm.org>> wrote:
> > Author: adrian
> > Date: Mon Mar  7 14:58:52 2016
> > New Revision: 262851
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=262851&view=rev <http://llvm.org/viewvc/llvm-project?rev=262851&view=rev>
> > Log:
> > Module Debugging: Fix a crash when emitting debug info for nested tag types
> > whose DeclContext is not yet complete by deferring their emission.
> >
> > rdar://problem/24918680
> >
> > Modified:
> >     cfe/trunk/lib/CodeGen/ObjectFilePCHContainerOperations.cpp
> >     cfe/trunk/test/Modules/Inputs/DebugCXX.h
> >     cfe/trunk/test/Modules/ModuleDebugInfo.cpp
> >
> > Modified: cfe/trunk/lib/CodeGen/ObjectFilePCHContainerOperations.cpp
> > URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/ObjectFilePCHContainerOperations.cpp?rev=262851&r1=262850&r2=262851&view=diff <http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/ObjectFilePCHContainerOperations.cpp?rev=262851&r1=262850&r2=262851&view=diff>
> > ==============================================================================
> > --- cfe/trunk/lib/CodeGen/ObjectFilePCHContainerOperations.cpp (original)
> > +++ cfe/trunk/lib/CodeGen/ObjectFilePCHContainerOperations.cpp Mon Mar  7 14:58:52 2016
> > @@ -201,6 +201,15 @@ public:
> >      if (D->getName().empty())
> >        return;
> >
> > +    // Defer tag decls until their declcontext is complete.
> > +    auto *DeclCtx = D->getDeclContext();
> > +    while (DeclCtx) {
> > +      if (auto *D = dyn_cast<TagDecl>(DeclCtx))
> > +        if (!D->isCompleteDefinition())
> > +          return;
> > +      DeclCtx = DeclCtx->getParent();
> > +    }
> > +
> >      DebugTypeVisitor DTV(*Builder->getModuleDebugInfo(), *Ctx);
> >      DTV.TraverseDecl(D);
> >      Builder->UpdateCompletedType(D);
> >
> > Modified: cfe/trunk/test/Modules/Inputs/DebugCXX.h
> > URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/Inputs/DebugCXX.h?rev=262851&r1=262850&r2=262851&view=diff <http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/Inputs/DebugCXX.h?rev=262851&r1=262850&r2=262851&view=diff>
> > ==============================================================================
> > --- cfe/trunk/test/Modules/Inputs/DebugCXX.h (original)
> > +++ cfe/trunk/test/Modules/Inputs/DebugCXX.h Mon Mar  7 14:58:52 2016
> > @@ -72,3 +72,14 @@ namespace {
> >      struct InAnonymousNamespace { int i; };
> >    }
> >  }
> > +
> > +class Base;
> > +class A {
> > +  virtual Base *getParent() const;
> > +};
> > +class Base {};
> > +class Derived : Base {
> > +  class B : A {
> > +    Derived *getParent() const override;
> > +  };
> > +};
> >
> > Modified: cfe/trunk/test/Modules/ModuleDebugInfo.cpp
> > URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/ModuleDebugInfo.cpp?rev=262851&r1=262850&r2=262851&view=diff <http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/ModuleDebugInfo.cpp?rev=262851&r1=262850&r2=262851&view=diff>
> > ==============================================================================
> > --- cfe/trunk/test/Modules/ModuleDebugInfo.cpp (original)
> > +++ cfe/trunk/test/Modules/ModuleDebugInfo.cpp Mon Mar  7 14:58:52 2016
> > @@ -71,6 +71,13 @@
> >  // CHECK-NOT:              name:
> >  // CHECK-SAME:             identifier: "_ZTS13TypedefStruct")
> >
> > +// CHECK: !DICompositeType(tag: DW_TAG_class_type, name: "Derived",
> > +// CHECK-SAME:             identifier: "_ZTS7Derived")
> > +// CHECK: !DICompositeType(tag: DW_TAG_class_type, name: "B", scope: !"_ZTS7Derived",
> > +// CHECK-SAME:             elements: ![[B_MBRS:.*]], vtableHolder: !"_ZTS1A"
> > +// CHECK: ![[B_MBRS]] = !{{{.*}}, ![[GET_PARENT:.*]]}
> > +// CHECK: ![[GET_PARENT]] = !DISubprogram(name: "getParent"
> > +
> >  // CHECK: !DIDerivedType(tag: DW_TAG_typedef, name: "FloatInstatiation"
> >  // no mangled name here yet.
> >
> >
> >
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> >
> 
> 

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