Re: [PATCH, testsuite] Fix PR37033, gcc.dg/pch/valid-1b.c failures

[Alexandre Oliva <aoliva at redhat dot com>]

On Nov 18, 2008, Jakub Jelinek <jakub@redhat.com> wrote:

> The rationale for the macro is to tell inline asm writers whether
> they can/should use .cfi* directives in their inline asm or not.

Hmm...  I just started working on a different approach to address this
problem, in the VTA branch.  My plan was to separate the can from the
should, and define the __GCC_HAVE_* macro based on can, as the name
sort of implies.  However...

> when .cfi_* directives are not emitted, using .cfi_rel_offset
> etc. in the inline asm will result in assembler errors,

... so I guess my patch won't quite work.

I guess it doesn't make sense to add this macro to the set of those
that can vary across PCH compilations either, like we used to tolerate
bumping -g down to -g0.  For asm code in the PCH will use unwanted
directives, and I guess that's where it's currently most likely to
be.

It's quite unfortunate that -g PCH files will no longer be used with
-g0, but I don't see any good way to avoid this.  Unless...  How about
we kept CFI generation enabled throughout the compiler, in spite of
-g0, when using a PCH that had it enabled?  Then we'd emit eh sections
that we didn't need, but that's about it AFAICT.

Thoughts?

-- 
Alexandre Oliva           http://www.lsd.ic.unicamp.br/~oliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/   FSF Latin America board member
Free Software Evangelist      Red Hat Brazil Compiler Engineer