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Link alias symbols together

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Make sure alias symbols resolve to the same address in program .bss or .data
section. This ensure for example that if a program reference environ (via an
extern char **environ declaration) and the libc change its value via the
__environ alias after the R_ARCH_COPY relocation have been performed, then
the program will see the new value.
This commit is contained in:
Thomas Preud'homme 2010-04-26 00:46:39 +02:00
parent 036ff17916
commit a28b18fa16
1 changed files with 20 additions and 0 deletions
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20
tccelf.c
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@ -1510,12 +1510,32 @@ static int elf_output_file(TCCState *s1, const char *filename)
sym - (ElfW(Sym) *)symtab_section->data); sym - (ElfW(Sym) *)symtab_section->data);
} else if (type == STT_OBJECT) { } else if (type == STT_OBJECT) {
unsigned long offset; unsigned long offset;
ElfW(Sym) *dynsym, *dynsym_end;
offset = bss_section->data_offset; offset = bss_section->data_offset;
/* XXX: which alignment ? */ /* XXX: which alignment ? */
offset = (offset + 16 - 1) & -16; offset = (offset + 16 - 1) & -16;
index = put_elf_sym(s1->dynsym, offset, esym->st_size, index = put_elf_sym(s1->dynsym, offset, esym->st_size,
esym->st_info, 0, esym->st_info, 0,
bss_section->sh_num, name); bss_section->sh_num, name);
/* Ensure symbol aliases (that is, symbols with
the same st_value) resolve to the same
address in program .bss or .data section. */
dynsym_end = (ElfW(Sym) *)
(s1->dynsymtab_section->data +
s1->dynsymtab_section->data_offset);
for(dynsym = (ElfW(Sym) *)s1->dynsymtab_section->data + 1;
dynsym < dynsym_end; dynsym++) {
if (dynsym->st_value == esym->st_value) {
char *dynname;
dynname = s1->dynsymtab_section->link->data
+ dynsym->st_name;
put_elf_sym(s1->dynsym, offset,
dynsym->st_size,
dynsym->st_info, 0,
bss_section->sh_num,
dynname);
}
}
put_elf_reloc(s1->dynsym, bss_section, put_elf_reloc(s1->dynsym, bss_section,
offset, R_COPY, index); offset, R_COPY, index);
offset += esym->st_size; offset += esym->st_size;