--> r261657.
Author: adrian <adrian@91177308-0d34-0410-b5e6-96231b3b80d8>
Date: Tue Feb 23 17:13:47 2016 +0000
Remove an unnecessary workaround introduced in r259975. (NFC)
Now that LLVM r259973 allows replacing a temporary type with another
temporary we can rely on the original implementation.
It is possible for enums to be created as part of
their own declcontext. In this case a FwdDecl will be created
twice. This doesn't cause a problem because both FwdDecls are
entered into the ReplaceMap: finalize() will replace the first
FwdDecl with the second and then replace the second with
complete type.
Thanks to echristo for pointing this out.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@261657
-- adrian
> On Feb 22, 2016, at 5:26 PM, Eric Christopher <[email protected]> wrote:
>
> Hi Adrian,
>
> On Sat, Feb 20, 2016 at 1:18 PM Adrian Prantl <[email protected]> wrote:
> This had me puzzled for a second, but then I figured out what happened :-)
> The “crash” I quoted in the commit message really was an assertion failure,
> to be precise, the very assertion I relaxed in LLVM r259973 in order to be
> able to defer the building of the DeclContext implemented by this commit.
> Even with the assertion removed, I still believe that implementing it this
> way preferable, as it avoids creating the enum a second time.
>
> > On Feb 19, 2016, at 7:05 PM, Eric Christopher <[email protected]> wrote:
> >
> > Hi Adrian,
> >
> > I'm taking a look at this and can't duplicate using the testcase you gave
> > without your patch(es) applied. It's also causing asserts in other code as
> > you can have the forward decl left around and the CU isn't a valid context.
>
> Do you happen to have an example handy? I don’t quite understand the problem
> from the description — shouldn’t the temporary fwddecl be RAUWed
> unconditionally after the DeclContext is created?
>
>
> I'd think so. It appears to get through to code generation unreplaced though
> and...
>
> If you’re blocked on this we can definitely revert the change in CGDebugInfo
> (but not the testcase), I just would like to understand what’s going on.
>
>
> I am a bit. I don't have a reduction at the moment small enough to debug
> what's wrong with this and the current patch doesn't appear necessary so I'm
> unable to debug the original problem at this point to try to help more.
>
> -eric
>
> -- adrian
>
> > Can you take a look/revert until you've got a different testcase? There's
> > not enough information in the commit to construct one up for you.
> >
> > Thanks!
> >
> > -eric
> >
> > On Fri, Feb 5, 2016 at 6:03 PM Adrian Prantl via cfe-commits
> > <[email protected]> wrote:
> > Author: adrian
> > Date: Fri Feb 5 19:59:09 2016
> > New Revision: 259975
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=259975&view=rev
> > Log:
> > Fix a crash when emitting dbeug info for forward-declared scoped enums.
> > It is possible for enums to be created as part of their own
> > declcontext. We need to cache a placeholder to avoid the type being
> > created twice before hitting the cache.
> >
> > <rdar://problem/24493203>
> >
> > Added:
> > cfe/trunk/test/CodeGenCXX/debug-info-scoped-class.cpp
> > Modified:
> > cfe/trunk/lib/CodeGen/CGDebugInfo.cpp
> >
> > Modified: cfe/trunk/lib/CodeGen/CGDebugInfo.cpp
> > URL:
> > http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGDebugInfo.cpp?rev=259975&r1=259974&r2=259975&view=diff
> > ==============================================================================
> > --- cfe/trunk/lib/CodeGen/CGDebugInfo.cpp (original)
> > +++ cfe/trunk/lib/CodeGen/CGDebugInfo.cpp Fri Feb 5 19:59:09 2016
> > @@ -2051,13 +2051,25 @@ llvm::DIType *CGDebugInfo::CreateEnumTyp
> > // If this is just a forward declaration, construct an appropriately
> > // marked node and just return it.
> > if (isImportedFromModule || !ED->getDefinition()) {
> > - llvm::DIScope *EDContext = getDeclContextDescriptor(ED);
> > llvm::DIFile *DefUnit = getOrCreateFile(ED->getLocation());
> > +
> > + // It is possible for enums to be created as part of their own
> > + // declcontext. We need to cache a placeholder to avoid the type being
> > + // created twice before hitting the cache.
> > + llvm::DIScope *EDContext = DBuilder.createReplaceableCompositeType(
> > + llvm::dwarf::DW_TAG_enumeration_type, "", TheCU, DefUnit, 0);
> > +
> > unsigned Line = getLineNumber(ED->getLocation());
> > StringRef EDName = ED->getName();
> > llvm::DIType *RetTy = DBuilder.createReplaceableCompositeType(
> > llvm::dwarf::DW_TAG_enumeration_type, EDName, EDContext, DefUnit,
> > Line,
> > 0, Size, Align, llvm::DINode::FlagFwdDecl, FullName);
> > +
> > + // Cache the enum type so it is available when building the declcontext
> > + // and replace the declcontect with the real thing.
> > + TypeCache[Ty].reset(RetTy);
> > + EDContext->replaceAllUsesWith(getDeclContextDescriptor(ED));
> > +
> > ReplaceMap.emplace_back(
> > std::piecewise_construct, std::make_tuple(Ty),
> > std::make_tuple(static_cast<llvm::Metadata *>(RetTy)));
> >
> > Added: cfe/trunk/test/CodeGenCXX/debug-info-scoped-class.cpp
> > URL:
> > http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/debug-info-scoped-class.cpp?rev=259975&view=auto
> > ==============================================================================
> > --- cfe/trunk/test/CodeGenCXX/debug-info-scoped-class.cpp (added)
> > +++ cfe/trunk/test/CodeGenCXX/debug-info-scoped-class.cpp Fri Feb 5
> > 19:59:09 2016
> > @@ -0,0 +1,15 @@
> > +// RUN: %clang_cc1 -emit-llvm -debug-info-kind=standalone -std=c++11 \
> > +// RUN: -triple thumbv7-apple-ios %s -o - | FileCheck %s
> > +
> > +// This forward-declared scoped enum will be created while building its own
> > +// declcontext. Make sure it is only emitted once.
> > +
> > +struct A {
> > + enum class Return;
> > + Return f1();
> > +};
> > +A::Return* f2() {}
> > +
> > +// CHECK: !DICompositeType(tag: DW_TAG_enumeration_type, name: "Return",
> > +// CHECK-SAME: flags: DIFlagFwdDecl,
> > +// CHECK-NOT: tag: DW_TAG_enumeration_type, name: "Return"
> >
> >
> > _______________________________________________
> > cfe-commits mailing list
> > [email protected]
> > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
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