glibc-linuxthreads-2.3.4-allow-gcc-4.0-rtld.patch

linux下编译交叉工具链的工具源码

See http://sources.redhat.com/ml/libc-hacker/2005-03/msg00008.html

From libc-hacker-return-8343-listarch-libc-hacker=sources dot redhat dot com at sources dot redhat dot com Sat Mar 05 09:21:18 2005
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Date: Sat, 5 Mar 2005 10:20:49 +0100
From: Jakub Jelinek <jakub at redhat dot com>
To: Ulrich Drepper <drepper at redhat dot com>, Roland McGrath <roland at redhat dot com>
Cc: Glibc hackers <libc-hacker at sources dot redhat dot com>
Subject: [PATCH] Fix build with GCC 4
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Reply-To: Jakub Jelinek <jakub at redhat dot com>
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Hi!

The thread_offsetof change just mirrors what Alan Modra did to NPTL
tcb-offsets.sym.  Apparently for GCC 4 an offsetof like expression,
but not really offsetof, is no longer constant folded and therefore
not suitable for "i" constraint.

The ELF_MACHINE_NO_RELA change is needed to avoid
rtld.c: In function '_dl_start':
dynamic-link.h:50: error: nested function 'elf_machine_rela_relative' declared but never defined
dynamic-link.h:47: error: nested function 'elf_machine_rela' declared but never defined
This is what happens.
rtld.c first includes dl-machine.h without RESOLVE_MAP
and without RTLD_BOOTSTRAP defined.  This means that ELF_MACHINE_NO_RELA
is not defined on i386/arm.  Later on it defines RESOLVE_MAP
and RTLD_BOOTSTRAP and includes dynamic-link.h which has:
# if ! ELF_MACHINE_NO_RELA
auto void __attribute__((always_inline))
elf_machine_rela (struct link_map *map, const ElfW(Rela) *reloc,
                  const ElfW(Sym) *sym, const struct r_found_version *version,
                  void *const reloc_addr);
auto void __attribute__((always_inline))
elf_machine_rela_relative (ElfW(Addr) l_addr, const ElfW(Rela) *reloc,
                           void *const reloc_addr);
# endif
and later on includes dl-machine.h which sees RTLD_BOOTSTRAP is
defined and defines ELF_MACHINE_NO_RELA and doesn't define
elf_machine_rela* nested functions.
But the prototypes were already defined and GCC 4 doesn't like this.
ELF_MACHINE_NO_RELA is only ever used in preprocessing conditionals
and never in defined ELF_MACHINE_NO_RELA, so the trick below
already defines ELF_MACHINE_NO_RELA to 1/0 depending on whether
RTLD_BOOTSTRAP is defined and thus the prototypes in dynamic-link.h
that are not desirable are gone.

2005-03-05  Jakub Jelinek  <[e-mail]>

	* sysdeps/i386/dl-machine.h (ELF_MACHINE_NO_RELA): Define
	unconditionally to (defined RTLD_BOOTSTRAP).
	* sysdeps/arm/dl-machine.h (ELF_MACHINE_NO_RELA): Likewise.
linuxthreads/
	* sysdeps/powerpc/tcb-offsets.sym (thread_offsetof): Rework for GCC 4.

--- libc/linuxthreads/sysdeps/powerpc/tcb-offsets.sym.jj	2005-03-04 14:21:29.000000000 -0500
+++ libc/linuxthreads/sysdeps/powerpc/tcb-offsets.sym	2005-03-04 14:26:29.000000000 -0500
@@ -8,7 +8,7 @@
 -- Abuse tls.h macros to derive offsets relative to the thread register.
 #  undef __thread_register
 #  define __thread_register	((void *) 0)
-#  define thread_offsetof(mem)	((void *) &THREAD_SELF->p_##mem - (void *) 0)
+#  define thread_offsetof(mem)	((ptrdiff_t) THREAD_SELF + offsetof (struct _pthread_descr_struct, p_##mem))
 
 # else