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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 <jakub@redhat.com>
* 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
--- libc/sysdeps/i386/dl-machine.h.jj 2005-02-16 20:16:33.000000000 -0500
+++ libc/sysdeps/i386/dl-machine.h 2005-03-04 16:50:32.313591897 -0500
@@ -301,9 +301,7 @@ elf_machine_plt_value (struct link_map *
/* The i386 never uses Elf32_Rela relocations for the dynamic linker.
Prelinked libraries may use Elf32_Rela though. */
-#ifdef RTLD_BOOTSTRAP
-# define ELF_MACHINE_NO_RELA 1
-#endif
+#define ELF_MACHINE_NO_RELA (defined RTLD_BOOTSTRAP)
#ifdef RESOLVE_MAP
--- libc/sysdeps/arm/dl-machine.h.jj 2005-03-01 15:34:40.000000000 -0500
+++ libc/sysdeps/arm/dl-machine.h 2005-03-04 16:50:43.913473979 -0500
@@ -353,9 +353,7 @@ elf_machine_plt_value (struct link_map *
/* ARM never uses Elf32_Rela relocations for the dynamic linker.
Prelinked libraries may use Elf32_Rela though. */
-#ifdef RTLD_BOOTSTRAP
-# define ELF_MACHINE_NO_RELA 1
-#endif
+#define ELF_MACHINE_NO_RELA (defined RTLD_BOOTSTRAP)
#ifdef RESOLVE
Jakub
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