[LLVMdev] [cfe-dev] RFC: Adding __INTEGRATED_ASSEMLER__ macro

[Rafael Espíndola]

> But you've just said: "the IAS does not support pre-UAL syntax". I think
> this precisely answers the question. Add
> "__has_feature(some_spelling_of_what_UAL_stands_for)" which says
> specifically that the UAL syntax is supported. And/or, __has_extension(...)
> for the name of the pre-UAL syntax which could hypothetically be supported
> as an extension, but isn't in Clang. And/or have the UAL-syntax specify a
> name of a preprocessor macro that all conforming compilers that support this
> syntax are required to define.
>
> Again, here we have a concrete behavioral feature that we can and should
> support testing for. This isn't about whether the assembler is integrated or
> not, it is about whether the assembler supports a particular syntax on a
> particular platform.

While exposing this would be conceptually OK, how would we implement
it? Take pre_ual_syntax for example. With "-c -integrated-as" we know
the answer is currently no since we don't implement it. But what about
"-no-integrated-as -S"? We have no idea where that assembly is going.
It might be sent to gas (has it) or back to us (doesn't have it) or
the ARM assembler (I don't thin it has it).

Cheers,
Rafael