Re: [PATCH, rs6000] Fix many powerpc*-linux ASAN test suite failures

[Peter Bergner <bergner at vnet dot ibm dot com>]

On Wed, 2014-07-16 at 11:23 +0200, Jakub Jelinek wrote: 
> On Wed, Jul 16, 2014 at 05:18:06AM -0400, David Edelsohn wrote:
> > This seems weird. Why wasn't this file included before or whenever it
> > was added for other *-linux targets?  This seems to define SPECs that
> > should have been necessary before now.
> 
> All other Linux targets where asan is supported got the right definitions
> from gnu-user.h, it was needed even on the older release branches.

Ok, I compiled a source file that #includes tm.h and looked at the -dD -E
output to see what macros get defined with and without this change.
There are a few macros the gnu-user.h defines that are identical to what
some of the rs6000/sysv4.h or rs6000/linux{,64}.h header files define, so
we could remove those.  There are some that are different too, so we'd
need to keep those.  The following are the macros that are identical:

... in rs6000/sysv4.h are:

    LINK_EH_SPEC
    NO_IMPLICIT_EXTERN_C

However, there are some non-linux (eg, freebsd, lynx, etc.) that also
include rs6000/sysv4.h and not gnu-user.h, so I think we need to keep
this defines in rs6000/sysv4.h...or I could move them to freebsd{,64}.h,
lynx.h, etc.  Your preference is???

...in rs6000/linux{,64}.h are:

    ASM_APP_ON
    ASM_APP_OFF
    CPLUSPLUS_CPP_SPEC
    LINK_GCC_C_SEQUENCE_SPEC
    USE_LD_AS_NEEDED
    TARGET_POSIX_IO

These we should be able to freely remove from rs6000/linux{,64}.h since
gnu-user.h provides the same identical definitions.

There are also a few macros that gnu-user.h defines that are different than
the what rs6000/*.h files define (eg, STARTFILE_SPEC, ENDFILE_SPEC, CC1_SPEC
LIB_SPEC and TARGET_LIBC_HAS_FUNCTION), so we'll want to leave those macro
definitions as well.

Peter