r230255 - Only lower __builtin_setjmp / __builtin_longjmp to

[John McCall]

On Tue, Mar 10, 2015 at 6:37 PM, Joerg Sonnenberger <joerg at britannica.bec.de
> wrote:

> On Tue, Mar 10, 2015 at 05:44:00PM -0700, John McCall wrote:
> > I'm sorry, I missed your early request, and your response to my review.
> > I'm much more likely to respond quickly if you keep me as a recipient.
> >
> > I really would like you to diagnose this in Sema, please.
> Target-specific
> > restrictions are not new, especially on builtin functions.  But if you do
> > that, it's approved for merge.
>
> But Sema is too early, it breaks valid use cases that are never going to
> hit the backend at all. Consider clang --analyze or clang-modernize.
> Especially the latter is completely target independent, so it shouldn't
> get fail on code that is valid on one platform and only fails on another
> because of LLVM bugs.
>

It's target-independent except for the thousands of ways that C code is not
target-independent.  Headers need to be in place and provide the right
declarations, hordes of warnings turn out differently based on type size,
printf format checking has target-specific logic, etc.

The way we (don't) implement them, __builtin_setjmp and __builtin_longjmp
are target-specific builtin functions, and they should be diagnosed along
with the rest of them.

John.
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