[PATCH] First set of patches for type uniquing

[Eli Friedman]

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++.

I'm not really a debug info expert, so this isn't a proper review.

-Eli