[llvm-commits] First patch to add support for variable address spaces to optimizers

[Eli Friedman]

On Wed, Oct 10, 2012 at 9:09 PM, Nick Lewycky <nicholas at mxc.ca> wrote:
> Eli Friedman wrote:
>>
>> On Wed, Oct 10, 2012 at 1:27 PM, Villmow, Micah<Micah.Villmow at amd.com>
>> wrote:
>>>
>>> This patch starts enabling proper use of the variable address space
>>> throughout LLVM.
>>> What this does is when it is known, it passes in the address space to the
>>> data layout for some functions.
>>> The next patch will contain the more intrusive changes of
>>> getIntPtrType/get*PtrTy/getPointerTy.
>>
>>
>> I'm sort of uncomfortable with the number of places you're hardcoding
>> "0"; can you add a function to DataLayout with a more explanatory
>> name?
>>
>> Index: include/llvm-c/Target.h
>> ===================================================================
>> --- include/llvm-c/Target.h     (revision 165622)
>> +++ include/llvm-c/Target.h     (working copy)
>> @@ -170,7 +170,7 @@
>>
>>   /** Returns the pointer size in bytes for a target.
>>       See the method llvm::DataLayout::getPointerSize. */
>> -unsigned LLVMPointerSize(LLVMTargetDataRef);
>> +unsigned LLVMPointerSize(LLVMTargetDataRef, unsigned AS);
>>
>> This change isn't acceptable; the C API is stable.  Add a new function
>> if necessary.
>
>
> Hey Eli, I'm not sure this is reasonable. There is a need to keep the C API
> ABI stable for libLTO and libIndex and a few high-level C libraries, but the
> main purpose of these C wrappers for all the C++ functions is to allow
> people to write language-specific bindings on top LLVM, and they don't need
> ABI stability. I've mentioned in the past that we should remove the
> ABI-stability requirement except for the libraries which have users that are
> really relying on that ABI guarantee.

Hmm... I'm not necessarily opposed, but can we document this somewhere?

-Eli