r228855 - Fix PR19351. While building up a composite type it is important to use

David Blaikie dblaikie at gmail.com
Wed Feb 11 11:06:53 PST 2015


On Wed, Feb 11, 2015 at 10:28 AM, Adrian Prantl <aprantl at apple.com> wrote:

>
> On Feb 11, 2015, at 10:21 AM, David Blaikie <dblaikie at gmail.com> wrote:
>
>
>
> On Wed, Feb 11, 2015 at 9:45 AM, Adrian Prantl <aprantl at apple.com> wrote:
>
>> Author: adrian
>> Date: Wed Feb 11 11:45:15 2015
>> New Revision: 228855
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=228855&view=rev
>> Log:
>> Fix PR19351. While building up a composite type it is important to use
>> a non-uniqueable temporary node that is only turned into a permanent
>> unique or distinct node after it is finished.
>> Otherwise an intermediate node may get accidentally uniqued with another
>> node as illustrated by the testcase.
>>
>
> Awesome - thanks!
>
>
>
> We should probably rename getOrCreateLimitedType() now, as it has nothing
> to do with limited debug info any more. Any suggestions?
>

I didn't catch the impact your change had on that function. What does it
have to do with now?


>
> -- adrian
>
>
>> Paired commit with LLVM.
>>
>> Added:
>>     cfe/trunk/test/CodeGen/debug-info-same-line.c
>> 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=228855&r1=228854&r2=228855&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/lib/CodeGen/CGDebugInfo.cpp (original)
>> +++ cfe/trunk/lib/CodeGen/CGDebugInfo.cpp Wed Feb 11 11:45:15 2015
>> @@ -621,6 +621,21 @@ static SmallString<256> getUniqueTagType
>>    return FullName;
>>  }
>>
>> +static llvm::dwarf::Tag getTagForRecord(const RecordDecl *RD) {
>> +   llvm::dwarf::Tag Tag;
>> +  if (RD->isStruct() || RD->isInterface())
>> +    Tag = llvm::dwarf::DW_TAG_structure_type;
>> +  else if (RD->isUnion())
>> +    Tag = llvm::dwarf::DW_TAG_union_type;
>> +  else {
>> +    // FIXME: This could be a struct type giving a default visibility
>> different
>> +    // than C++ class type, but needs llvm metadata changes first.
>> +    assert(RD->isClass());
>> +    Tag = llvm::dwarf::DW_TAG_class_type;
>> +  }
>> +  return Tag;
>> +}
>> +
>>  // Creates a forward declaration for a RecordDecl in the given context.
>>  llvm::DICompositeType
>>  CGDebugInfo::getOrCreateRecordFwdDecl(const RecordType *Ty,
>> @@ -632,20 +647,12 @@ CGDebugInfo::getOrCreateRecordFwdDecl(co
>>    unsigned Line = getLineNumber(RD->getLocation());
>>    StringRef RDName = getClassName(RD);
>>
>> -  llvm::dwarf::Tag Tag;
>> -  if (RD->isStruct() || RD->isInterface())
>> -    Tag = llvm::dwarf::DW_TAG_structure_type;
>> -  else if (RD->isUnion())
>> -    Tag = llvm::dwarf::DW_TAG_union_type;
>> -  else {
>> -    assert(RD->isClass());
>> -    Tag = llvm::dwarf::DW_TAG_class_type;
>> -  }
>>
>>    // Create the type.
>>    SmallString<256> FullName = getUniqueTagTypeName(Ty, CGM, TheCU);
>> -  llvm::DICompositeType RetTy = DBuilder.createReplaceableForwardDecl(
>> -      Tag, RDName, Ctx, DefUnit, Line, 0, 0, 0, FullName);
>> +  llvm::DICompositeType RetTy = DBuilder.createReplaceableCompositeType(
>> +      getTagForRecord(RD), RDName, Ctx, DefUnit, Line, 0, 0, 0,
>> +      llvm::DIDescriptor::FlagFwdDecl, FullName);
>>    ReplaceMap.emplace_back(
>>        std::piecewise_construct, std::make_tuple(Ty),
>>        std::make_tuple(static_cast<llvm::Metadata *>(RetTy)));
>> @@ -1567,7 +1574,8 @@ llvm::DIType CGDebugInfo::CreateTypeDefi
>>    assert(FwdDecl.isCompositeType() &&
>>           "The debug type of a RecordType should be a
>> llvm::DICompositeType");
>>
>> -  if (FwdDecl.isForwardDecl())
>> +  const RecordDecl *D = RD->getDefinition();
>> +  if (!D || !D->isCompleteDefinition())
>>      return FwdDecl;
>>
>>    if (const CXXRecordDecl *CXXDecl = dyn_cast<CXXRecordDecl>(RD))
>> @@ -1602,6 +1610,10 @@ llvm::DIType CGDebugInfo::CreateTypeDefi
>>    llvm::DIArray Elements = DBuilder.getOrCreateArray(EltTys);
>>    DBuilder.replaceArrays(FwdDecl, Elements);
>>
>> +  if (FwdDecl->isTemporary())
>> +    FwdDecl = llvm::DICompositeType(llvm::MDNode::replaceWithPermanent(
>> +      llvm::TempMDNode(FwdDecl.get())));
>> +
>>    RegionMap[Ty->getDecl()].reset(FwdDecl);
>>    return FwdDecl;
>>  }
>> @@ -1653,7 +1665,7 @@ llvm::DIType CGDebugInfo::CreateType(con
>>    // debug type since we won't be able to lay out the entire type.
>>    ObjCInterfaceDecl *Def = ID->getDefinition();
>>    if (!Def || !Def->getImplementation()) {
>> -    llvm::DIType FwdDecl = DBuilder.createReplaceableForwardDecl(
>> +    llvm::DIType FwdDecl = DBuilder.createReplaceableCompositeType(
>>          llvm::dwarf::DW_TAG_structure_type, ID->getName(), TheCU,
>> DefUnit, Line,
>>          RuntimeLang);
>>      ObjCInterfaceCache.push_back(ObjCInterfaceCacheEntry(Ty, FwdDecl,
>> Unit));
>> @@ -1933,9 +1945,9 @@ llvm::DIType CGDebugInfo::CreateEnumType
>>      llvm::DIFile DefUnit = getOrCreateFile(ED->getLocation());
>>      unsigned Line = getLineNumber(ED->getLocation());
>>      StringRef EDName = ED->getName();
>> -    llvm::DIType RetTy = DBuilder.createReplaceableForwardDecl(
>> +    llvm::DIType RetTy = DBuilder.createReplaceableCompositeType(
>>          llvm::dwarf::DW_TAG_enumeration_type, EDName, EDContext,
>> DefUnit, Line,
>> -        0, Size, Align, FullName);
>> +        0, Size, Align, llvm::DIDescriptor::FlagFwdDecl, FullName);
>>      ReplaceMap.emplace_back(
>>          std::piecewise_construct, std::make_tuple(Ty),
>>          std::make_tuple(static_cast<llvm::Metadata *>(RetTy)));
>> @@ -2249,19 +2261,8 @@ llvm::DICompositeType CGDebugInfo::Creat
>>
>>    SmallString<256> FullName = getUniqueTagTypeName(Ty, CGM, TheCU);
>>
>> -  if (RD->isUnion())
>> -    RealDecl = DBuilder.createUnionType(RDContext, RDName, DefUnit,
>> Line, Size,
>> -                                        Align, 0, llvm::DIArray(), 0,
>> FullName);
>> -  else if (RD->isClass()) {
>> -    // FIXME: This could be a struct type giving a default visibility
>> different
>> -    // than C++ class type, but needs llvm metadata changes first.
>> -    RealDecl = DBuilder.createClassType(
>> -        RDContext, RDName, DefUnit, Line, Size, Align, 0, 0,
>> llvm::DIType(),
>> -        llvm::DIArray(), llvm::DIType(), llvm::DIArray(), FullName);
>> -  } else
>> -    RealDecl = DBuilder.createStructType(
>> -        RDContext, RDName, DefUnit, Line, Size, Align, 0, llvm::DIType(),
>> -        llvm::DIArray(), 0, llvm::DIType(), FullName);
>> +  RealDecl = DBuilder.createReplaceableCompositeType(getTagForRecord(RD),
>> +      RDName, RDContext, DefUnit, Line, 0, Size, Align, 0, FullName);
>>
>>    RegionMap[Ty->getDecl()].reset(RealDecl);
>>    TypeCache[QualType(Ty, 0).getAsOpaquePtr()].reset(RealDecl);
>>
>> Added: cfe/trunk/test/CodeGen/debug-info-same-line.c
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/debug-info-same-line.c?rev=228855&view=auto
>>
>> ==============================================================================
>> --- cfe/trunk/test/CodeGen/debug-info-same-line.c (added)
>> +++ cfe/trunk/test/CodeGen/debug-info-same-line.c Wed Feb 11 11:45:15 2015
>> @@ -0,0 +1,7 @@
>> +// RUN: %clang_cc1 -triple x86_64-apple-darwin -emit-llvm %s -g -o - |
>> FileCheck %s
>> +// Here two temporary nodes are identical (but should not get uniqued)
>> while
>> +// building the full debug type.
>> +typedef struct { long x; } foo; typedef struct {  foo *x; } bar;
>> +// CHECK: [ DW_TAG_structure_type ] [line 4, size 64,
>> +// CHECK: [ DW_TAG_structure_type ] [line 4, size 64,
>> +bar b;
>>
>>
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>>
>
>
>
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