[PATCH] First set of patches for type uniquing

[Manman Ren]

On 8/2/13, 4:31 PM, Eli Friedman wrote:
> On Wed, Jul 31, 2013 at 4:37 PM, Manman Ren <manman.ren at gmail.com> wrote:
>> After cleaning up usage of the verify function and all the testing cases,
>> the first set of patches are ready for review :)
>>
>> 3 patches are included: one for clang (tu_clang_07312013.patch), one for
>> code change of llvm (tu_07312013.patch), and one for updating all the
>> testing cases (tu_test_07312013.patch).
>>
>> The following are implemented:
>> 1> DIType will have a unique name at field 9.
>>       For DIBasicType, DICompositeType, DIDerivedType, the fields after will
>> be shifted by 1.
>> 2> I am going to update usage of DIType in phases:
>>       At the first batch, getContainingType of DICompositeType and
>> DISubprogram will be replaced with a MDString, as well as getClassType of
>> DIDerivedType.
>> 3> The verifier is updated according to 1 and 2.
>> 4> DwarfDebug has a TypeMap.
>>        It also has a helper function lookupType to find the corresponding
>> DIType given a type name.
>> 5> how to generate the unique name?
>>        The clang frontend has two helper functions: getUniqueTagTypeName and
>> getUniqueTypeName
>>            The first one handles TagType and it uses ODR (One Definition
>> Rule) for external c++ types. It is currently called for struct, class,
>> union and enum.
>>            The second one can be used for general types, it uses mangled name
>> appended with CU's directory and file name to provide uniqueness across CUs.
>> It is currently used to generate unique name for subroutine type. For other
>> types, DIBuilder will provide a unique name. Clang can handle more types in
>> follow-on patches if it can provide a better name than DIBuilder.
>>        DIBuilder also has a helper function getUniqueTypeName, this is called
>> when consumer of DIBuilder does not provide a unique type name. This is
>> needed for dragonegg, before it provides a unique name (not sure whether it
>> is needed).
>> 6> All DITypes created by DIBuilder will be added to RetainTypes.
>>
>> Comments and feedback are welcome.
> Comments on the clang side:
>
> Please don't call mangleCXXRTTIName outside of C++.  Also, please use
> getLangOpts().CPlusPlus to check whether we are in C++.
Thanks for the comments.

Yes, I should check the language first before calling mangleCXXRTTIName 
and will use DIBuilder to provide a unique
name for other languages.

Language tag of the CompileUnit is set to C_plus_plus when 
getLangOpts().CPlusPlus and
!getLangOpts().Objc1. I choose to turn on ODR only for C++ 
(TheCU.getLanguage() == DW_LANG_C_plus_plus),
not ObjC++, since I am not sure about the existence of a standard about 
ODR for ObjC++.

Thanks,
Manman
>
> I'm not really a debug info expert, so this isn't a proper review.
>
> -Eli