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elf: Move elf_dynamic_do_Rel RTLD_BOOTSTRAP branches outside 

elf_dynamic_do_Rel checks RTLD_BOOTSTRAP in several #ifdef branches.
Create an outside RTLD_BOOTSTRAP branch to simplify reasoning about the
function at the cost of a few duplicate lines.

Since dl_naudit is zero in RTLD_BOOTSTRAP code, the RTLD_BOOTSTRAP
branch can avoid _dl_audit_symbind calls to decrease code size.

Reviewed-by: Adheemrval Zanella  <adhemerval.zanella@linaro.org>
This commit is contained in:
Fangrui Song 2022-04-20 13:52:45 -07:00
parent a8e9b5b807
commit 84e02af1eb
1 changed files with 28 additions and 21 deletions
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49
elf/do-rel.h
View File

@ -45,15 +45,35 @@ elf_dynamic_do_Rel (struct link_map *map, struct r_scope_elem *scope[],
__typeof (((ElfW(Dyn) *) 0)->d_un.d_val) nrelative,
int lazy, int skip_ifunc)
{
const ElfW(Rel) *r = (const void *) reladdr;
const ElfW(Rel) *relative = (const void *) reladdr;
const ElfW(Rel) *r = relative + nrelative;
const ElfW(Rel) *end = (const void *) (reladdr + relsize);
ElfW(Addr) l_addr = map->l_addr;
# if defined ELF_MACHINE_IRELATIVE && !defined RTLD_BOOTSTRAP
const ElfW(Sym) *const symtab
= (const void *) D_PTR (map, l_info[DT_SYMTAB]);
#ifdef RTLD_BOOTSTRAP
for (; relative < r; ++relative)
DO_ELF_MACHINE_REL_RELATIVE (map, l_addr, relative);
const ElfW (Half) *const version
= (const void *) D_PTR (map, l_info[VERSYMIDX (DT_VERSYM)]);
for (; r < end; ++r)
{
ElfW (Half) ndx = version[ELFW (R_SYM) (r->r_info)] & 0x7fff;
const ElfW (Sym) *sym = &symtab[ELFW (R_SYM) (r->r_info)];
void *const r_addr_arg = (void *) (l_addr + r->r_offset);
const struct r_found_version *rversion = &map->l_versions[ndx];
elf_machine_rel (map, scope, r, sym, rversion, r_addr_arg, skip_ifunc);
}
#else /* !RTLD_BOOTSTRAP */
# if defined ELF_MACHINE_IRELATIVE
const ElfW(Rel) *r2 = NULL;
const ElfW(Rel) *end2 = NULL;
# endif
#if (!defined DO_RELA || !defined ELF_MACHINE_PLT_REL) && !defined RTLD_BOOTSTRAP
#if !defined DO_RELA || !defined ELF_MACHINE_PLT_REL
/* We never bind lazily during ld.so bootstrap. Unfortunately gcc is
not clever enough to see through all the function calls to realize
that. */
@ -82,12 +102,6 @@ elf_dynamic_do_Rel (struct link_map *map, struct r_scope_elem *scope[],
else
#endif
{
const ElfW(Sym) *const symtab =
(const void *) D_PTR (map, l_info[DT_SYMTAB]);
const ElfW(Rel) *relative = r;
r += nrelative;
#ifndef RTLD_BOOTSTRAP
/* This is defined in rtld.c, but nowhere in the static libc.a; make
the reference weak so static programs can still link. This
declaration cannot be done when compiling rtld.c (i.e. #ifdef
@ -106,16 +120,10 @@ elf_dynamic_do_Rel (struct link_map *map, struct r_scope_elem *scope[],
memory_loc += l_addr... */
if (l_addr != 0)
# endif
#endif
for (; relative < r; ++relative)
DO_ELF_MACHINE_REL_RELATIVE (map, l_addr, relative);
#ifdef RTLD_BOOTSTRAP
/* The dynamic linker always uses versioning. */
assert (map->l_info[VERSYMIDX (DT_VERSYM)] != NULL);
#else
if (map->l_info[VERSYMIDX (DT_VERSYM)])
#endif
{
const ElfW(Half) *const version =
(const void *) D_PTR (map, l_info[VERSYMIDX (DT_VERSYM)]);
@ -126,7 +134,7 @@ elf_dynamic_do_Rel (struct link_map *map, struct r_scope_elem *scope[],
const ElfW(Sym) *sym = &symtab[ELFW(R_SYM) (r->r_info)];
void *const r_addr_arg = (void *) (l_addr + r->r_offset);
const struct r_found_version *rversion = &map->l_versions[ndx];
#if defined ELF_MACHINE_IRELATIVE && !defined RTLD_BOOTSTRAP
#if defined ELF_MACHINE_IRELATIVE
if (ELFW(R_TYPE) (r->r_info) == ELF_MACHINE_IRELATIVE)
{
if (r2 == NULL)
@ -138,7 +146,7 @@ elf_dynamic_do_Rel (struct link_map *map, struct r_scope_elem *scope[],
elf_machine_rel (map, scope, r, sym, rversion, r_addr_arg,
skip_ifunc);
#if defined SHARED && !defined RTLD_BOOTSTRAP
#if defined SHARED
if (ELFW(R_TYPE) (r->r_info) == ELF_MACHINE_JMP_SLOT
&& GLRO(dl_naudit) > 0)
{
@ -151,7 +159,7 @@ elf_dynamic_do_Rel (struct link_map *map, struct r_scope_elem *scope[],
#endif
}
#if defined ELF_MACHINE_IRELATIVE && !defined RTLD_BOOTSTRAP
#if defined ELF_MACHINE_IRELATIVE
if (r2 != NULL)
for (; r2 <= end2; ++r2)
if (ELFW(R_TYPE) (r2->r_info) == ELF_MACHINE_IRELATIVE)
@ -166,7 +174,6 @@ elf_dynamic_do_Rel (struct link_map *map, struct r_scope_elem *scope[],
}
#endif
}
#ifndef RTLD_BOOTSTRAP
else
{
for (; r < end; ++r)
@ -184,7 +191,7 @@ elf_dynamic_do_Rel (struct link_map *map, struct r_scope_elem *scope[],
# endif
elf_machine_rel (map, scope, r, sym, NULL, r_addr_arg,
skip_ifunc);
# if defined SHARED && !defined RTLD_BOOTSTRAP
# if defined SHARED
if (ELFW(R_TYPE) (r->r_info) == ELF_MACHINE_JMP_SLOT
&& GLRO(dl_naudit) > 0)
{
@ -207,8 +214,8 @@ elf_dynamic_do_Rel (struct link_map *map, struct r_scope_elem *scope[],
skip_ifunc);
# endif
}
#endif
}
#endif /* !RTLD_BOOTSTRAP */
}
#undef elf_dynamic_do_Rel