[cfe-commits] r161236 - in /cfe/trunk:

[David Blaikie]

On Fri, Aug 3, 2012 at 8:18 AM, Benjamin Kramer <benny.kra at gmail.com> wrote:
>
> On 03.08.2012, at 16:34, David Blaikie <dblaikie at gmail.com> wrote:
>
>> lib/AST/RecordLayoutBuilder.cpp
>>
>> test/CodeGenCXX/cxx11-vtable-key-function.cpp
>> MIME-Version: 1.0
>> Content-Type: text/plain; charset="utf-8"
>> Content-Transfer-Encoding: 7bit
>>
>> Why can't the key function have a (non inline) = default definition?
>
> It can.
>
>> What happens if the only non inline virtual functions are = defaulted?
>
> From the documentation of CXXMethodDecl::isUserProvided:
>
>> True if this method is user-declared and was not deleted or defaulted on its *first declaration*
>
> So this should not affect out-of-line defaulted key functions, it only prevents inline defaulted functions from being promoted to a key function.

Hmm, OK - should such definitions be considered 'inline' (since
they're defined within the class) from both/either a standards
perspective or a Clang-implementation-convenience perspective? Then
this would fall out naturally from the inline check without the need
for an isUserProvided check?

[& is there any better name for isUserProvided that might more
accurately describe the semantics? (I still need to go back & fix some
of the isDeleted/isDeletedAsWritten names/usages... they're also
rather confusing in some similar ways)]

(& would it be worth having a test case to demonstrate that the out of
line = default definition does get treated as a key function?)

>
> - Ben
>
>> From: Benjamin Kramer
>> Sent: 8/3/2012 1:42 AM
>> To: cfe-commits at cs.uiuc.edu
>> Subject: [cfe-commits] r161236 - in /cfe/trunk:
>> lib/AST/RecordLayoutBuilder.cpp
>> test/CodeGenCXX/cxx11-vtable-key-function.cpp
>> Author: d0k
>> Date: Fri Aug  3 03:39:58 2012
>> New Revision: 161236
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=161236&view=rev
>> Log:
>> Fix failed to generate vtables in certain cases.
>>
>> By C++ standard, the vtable should be generated if the first non-inline
>> virtual function is defined in the TU.  Current version of clang doesn't
>> generate vtable if the first virtual function is defaulted, because the
>> key function is regarded as the defaulted function.
>>
>> Patch by Li Kan!
>>
>> Added:
>>    cfe/trunk/test/CodeGenCXX/cxx11-vtable-key-function.cpp
>> Modified:
>>    cfe/trunk/lib/AST/RecordLayoutBuilder.cpp
>>
>> Modified: cfe/trunk/lib/AST/RecordLayoutBuilder.cpp
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/RecordLayoutBuilder.cpp?rev=161236&r1=161235&r2=161236&view=diff
>> ==============================================================================
>> --- cfe/trunk/lib/AST/RecordLayoutBuilder.cpp (original)
>> +++ cfe/trunk/lib/AST/RecordLayoutBuilder.cpp Fri Aug  3 03:39:58 2012
>> @@ -2351,6 +2351,9 @@
>>     if (MD->hasInlineBody())
>>       continue;
>>
>> +    if (!MD->isUserProvided())
>> +      continue;
>> +
>>     // We found it.
>>     return MD;
>>   }
>>
>> Added: cfe/trunk/test/CodeGenCXX/cxx11-vtable-key-function.cpp
>> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/cxx11-vtable-key-function.cpp?rev=161236&view=auto
>> ==============================================================================
>> --- cfe/trunk/test/CodeGenCXX/cxx11-vtable-key-function.cpp (added)
>> +++ cfe/trunk/test/CodeGenCXX/cxx11-vtable-key-function.cpp Fri Aug  3
>> 03:39:58 2012
>> @@ -0,0 +1,11 @@
>> +// RUN: %clang_cc1 %s -triple=x86_64-apple-darwin10 -emit-llvm -o -
>> -std=c++11 | FileCheck %s
>> +// PR13424
>> +
>> +struct X {
>> +  virtual ~X() = default;
>> +  virtual void f();
>> +};
>> +
>> +void X::f() {}
>> +
>> +// CHECK: @_ZTV1X = unnamed_addr constant
>>
>>
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>