r227796 - MS ABI: Implement support for 'novtable'

[Aaron Ballman]

On Mon, Feb 2, 2015 at 2:07 PM, David Majnemer <david.majnemer at gmail.com> wrote:
> Done in r227838.

Thanks! Looks great to me!

~Aaron

>
> On Mon, Feb 2, 2015 at 4:40 AM, Aaron Ballman <aaron at aaronballman.com>
> wrote:
>>
>> On Mon, Feb 2, 2015 at 5:22 AM, David Majnemer <david.majnemer at gmail.com>
>> wrote:
>> > Author: majnemer
>> > Date: Mon Feb  2 04:22:20 2015
>> > New Revision: 227796
>> >
>> > URL: http://llvm.org/viewvc/llvm-project?rev=227796&view=rev
>> > Log:
>> > MS ABI: Implement support for 'novtable'
>> >
>> > It is common for COM interface classes to be marked as 'novtable' to
>> > tell the compiler that constructors and destructors should not reference
>> > virtual function tables.
>> >
>> > This commit implements this feature in clang.
>> >
>> > Modified:
>> >     cfe/trunk/include/clang/Basic/Attr.td
>> >     cfe/trunk/lib/CodeGen/CGClass.cpp
>> >     cfe/trunk/lib/CodeGen/MicrosoftCXXABI.cpp
>> >     cfe/trunk/lib/Sema/SemaDeclAttr.cpp
>> >     cfe/trunk/test/Parser/MicrosoftExtensions.cpp
>> >
>> > Modified: cfe/trunk/include/clang/Basic/Attr.td
>> > URL:
>> > http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/Attr.td?rev=227796&r1=227795&r2=227796&view=diff
>> >
>> > ==============================================================================
>> > --- cfe/trunk/include/clang/Basic/Attr.td (original)
>> > +++ cfe/trunk/include/clang/Basic/Attr.td Mon Feb  2 04:22:20 2015
>> > @@ -1761,6 +1761,12 @@ def TypeTagForDatatype : InheritableAttr
>> >
>> >  // Microsoft-related attributes
>> >
>> > +def MsNoVTable : InheritableAttr {
>> > +  let Spellings = [Declspec<"novtable">];
>> > +  let Subjects = SubjectList<[CXXRecord]>;
>> > +  let Documentation = [Undocumented];
>>
>> No undocumented attributes, please.
>>
>> > +}
>> > +
>> >  def MsProperty : IgnoredAttr {
>> >    let Spellings = [Declspec<"property">];
>> >  }
>> >
>> > Modified: cfe/trunk/lib/CodeGen/CGClass.cpp
>> > URL:
>> > http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGClass.cpp?rev=227796&r1=227795&r2=227796&view=diff
>> >
>> > ==============================================================================
>> > --- cfe/trunk/lib/CodeGen/CGClass.cpp (original)
>> > +++ cfe/trunk/lib/CodeGen/CGClass.cpp Mon Feb  2 04:22:20 2015
>> > @@ -1949,6 +1949,14 @@ CodeGenFunction::InitializeVTablePointer
>> >                                           const CXXRecordDecl
>> > *NearestVBase,
>> >                                           CharUnits
>> > OffsetFromNearestVBase,
>> >                                           const CXXRecordDecl
>> > *VTableClass) {
>> > +  const CXXRecordDecl *RD = Base.getBase();
>> > +
>> > +  // Don't initialize the vtable pointer if the class is marked with
>> > the
>> > +  // 'novtable' attribute.
>> > +  if ((RD == VTableClass || RD == NearestVBase) &&
>> > +      VTableClass->hasAttr<MsNoVTableAttr>())
>> > +    return;
>> > +
>> >    // Compute the address point.
>> >    bool NeedsVirtualOffset;
>> >    llvm::Value *VTableAddressPoint =
>> >
>> > Modified: cfe/trunk/lib/CodeGen/MicrosoftCXXABI.cpp
>> > URL:
>> > http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/MicrosoftCXXABI.cpp?rev=227796&r1=227795&r2=227796&view=diff
>> >
>> > ==============================================================================
>> > --- cfe/trunk/lib/CodeGen/MicrosoftCXXABI.cpp (original)
>> > +++ cfe/trunk/lib/CodeGen/MicrosoftCXXABI.cpp Mon Feb  2 04:22:20 2015
>> > @@ -1582,7 +1582,8 @@ void MicrosoftCXXABI::emitVirtualInherit
>> >    for (unsigned I = 0, E = VBGlobals.VBTables->size(); I != E; ++I) {
>> >      const VPtrInfo *VBT = (*VBGlobals.VBTables)[I];
>> >      llvm::GlobalVariable *GV = VBGlobals.Globals[I];
>> > -    emitVBTableDefinition(*VBT, RD, GV);
>> > +    if (GV->isDeclaration())
>> > +      emitVBTableDefinition(*VBT, RD, GV);
>> >    }
>> >  }
>> >
>> > @@ -1609,6 +1610,9 @@ MicrosoftCXXABI::getAddrOfVBTable(const
>> >    else if (RD->hasAttr<DLLExportAttr>())
>> >      GV->setDLLStorageClass(llvm::GlobalValue::DLLExportStorageClass);
>> >
>> > +  if (!GV->hasExternalLinkage())
>> > +    emitVBTableDefinition(VBT, RD, GV);
>> > +
>> >    return GV;
>> >  }
>> >
>> >
>> > Modified: cfe/trunk/lib/Sema/SemaDeclAttr.cpp
>> > URL:
>> > http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDeclAttr.cpp?rev=227796&r1=227795&r2=227796&view=diff
>> >
>> > ==============================================================================
>> > --- cfe/trunk/lib/Sema/SemaDeclAttr.cpp (original)
>> > +++ cfe/trunk/lib/Sema/SemaDeclAttr.cpp Mon Feb  2 04:22:20 2015
>> > @@ -4689,6 +4689,9 @@ static void ProcessDeclAttribute(Sema &S
>> >      break;
>> >
>> >    // Microsoft attributes:
>> > +  case AttributeList::AT_MsNoVTable:
>> > +    handleSimpleAttribute<MsNoVTableAttr>(S, D, Attr);
>> > +    break;
>> >    case AttributeList::AT_MsStruct:
>> >      handleSimpleAttribute<MsStructAttr>(S, D, Attr);
>> >      break;
>> >
>> > Modified: cfe/trunk/test/Parser/MicrosoftExtensions.cpp
>> > URL:
>> > http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Parser/MicrosoftExtensions.cpp?rev=227796&r1=227795&r2=227796&view=diff
>> >
>> > ==============================================================================
>> > --- cfe/trunk/test/Parser/MicrosoftExtensions.cpp (original)
>> > +++ cfe/trunk/test/Parser/MicrosoftExtensions.cpp Mon Feb  2 04:22:20
>> > 2015
>> > @@ -339,7 +339,7 @@ void TestProperty() {
>> >  //expected-warning at +1 {{C++ operator 'and' (aka '&&') used as a macro
>> > name}}
>> >  #define and foo
>> >
>> > -struct __declspec(uuid("00000000-0000-0000-C000-000000000046"))
>> > __declspec(novtable) IUnknown {}; // expected-warning{{__declspec attribute
>> > 'novtable' is not supported}}
>> > +struct __declspec(uuid("00000000-0000-0000-C000-000000000046"))
>> > __declspec(novtable) IUnknown {};
>>
>> I would like to see some tests that ensure it accepts no arguments,
>> and cannot apply to something other than a CXXRecordDecl.
>>
>> Thank you for implementing this!
>>
>> ~Aaron
>>
>> >
>> >  typedef bool (__stdcall __stdcall *blarg)(int);
>> >
>> >
>> >
>> > _______________________________________________
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>> > cfe-commits at cs.uiuc.edu
>> > http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
>
>