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From: David Miller <davem@davemloft.net>
To: gcc@gcc.gnu.org
Subject: LTO and asm specs...
Date: Sat, 13 Mar 2010 12:42:00 -0000	[thread overview]
Message-ID: <20100312.213314.26520911.davem@davemloft.net> (raw)


There is one g++ LTO test case (g++.lto/20090303) that fails on sparc,
it compiles the intermediate objects with -fPIC but the final
compilation creates an executable.

The problem is that when LTO re-instantiates the options for the
individual builds, the proper ASM specs of the target are not
executed, so in this case "-K PIC" is not passed down to the assembler
in response to "-fPIC".

As a consequence, relocations against _GLOBAL_OFFSET_TABLE_
in code like this:

	sethi	%hi(_GLOBAL_OFFSET_TABLE_), %g1

use the R_SPARC_HI22 relocation instead of R_SPARC_PC22.

Thus the program crashes.

I couldn't figure out immediately how to fix this as the
way LTO does spec overriding and such looked non-trivial.

Thanks.

             reply	other threads:[~2010-03-13  5:33 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-13 12:42 David Miller [this message]
2010-03-16 19:28 ` Richard Henderson
2010-03-16 19:34   ` David Miller
2010-03-16 19:57     ` Richard Henderson
2010-03-16 19:58       ` David Miller
2010-03-16 20:14     ` H.J. Lu

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