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Make build_got_entries more target independent

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Factor most of common logic between targets in build_got_entries by
defining target specific info into structures in the backends.
This commit is contained in:
Thomas Preud'homme
2016-11-12 23:16:07 +08:00
parent 523b55d82d
commit 1c811a4d1d
11 changed files with 184 additions and 216 deletions
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275
tccelf.c
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@ -1022,6 +1022,7 @@ ST_FUNC void build_got_entries(TCCState *s1)
ElfW_Rel *rel;
ElfW(Sym) *sym;
int i, type, reloc_type, sym_index;
unsigned long ofs;
for(i = 1; i < s1->nb_sections; i++) {
s = s1->sections[i];
@ -1034,222 +1035,70 @@ ST_FUNC void build_got_entries(TCCState *s1)
type = ELFW(R_TYPE)(rel->r_info);
sym_index = ELFW(R_SYM)(rel->r_info);
sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
switch(type) {
#if defined(TCC_TARGET_I386)
case R_386_PC16:
case R_386_PC32:
case R_386_GOT32:
case R_386_GOT32X:
case R_386_GOTOFF:
case R_386_GOTPC:
case R_386_PLT32:
if (sym->st_shndx != SHN_UNDEF && type != R_386_GOT32 &&
type != R_386_GOT32X && type != R_386_GOTOFF &&
type != R_386_GOTPC && type != R_386_PLT32)
break;
if (relocs_info[type].gotplt_entry == NO_GOTPLT_ENTRY)
continue;
if (!s1->got)
build_got(s1);
/* Proceed with PLT/GOT [entry] creation if any of the following
condition is met:
- it is an undefined reference (dynamic relocation needed)
- symbol is absolute (probably created by tcc_add_symbol)
- relocation requires a PLT/GOT (BUILD_GOTPLT_ENTRY or
ALWAYS_GOTPLT_ENTRY). */
if (sym->st_shndx != SHN_UNDEF &&
sym->st_shndx != SHN_ABS &&
relocs_info[type].gotplt_entry == AUTO_GOTPLT_ENTRY)
continue;
if (type != R_386_GOTOFF && type != R_386_GOTPC) {
/* look at the symbol got offset. If none, then add one */
if (type == R_386_GOT32 || type == R_386_GOT32X)
reloc_type = R_386_GLOB_DAT;
else
reloc_type = R_386_JMP_SLOT;
put_got_entry(s1, reloc_type, sym->st_size, sym->st_info,
sym_index);
}
break;
#elif defined(TCC_TARGET_ARM)
case R_ARM_PC24:
case R_ARM_CALL:
case R_ARM_JUMP24:
case R_ARM_PLT32:
case R_ARM_THM_PC22:
case R_ARM_MOVT_ABS:
case R_ARM_MOVW_ABS_NC:
case R_ARM_THM_MOVT_ABS:
case R_ARM_THM_MOVW_ABS_NC:
case R_ARM_PREL31:
case R_ARM_REL32:
case R_ARM_GOTPC:
case R_ARM_GOTOFF:
case R_ARM_GOT32:
case R_ARM_V4BX:
if (sym->st_shndx != SHN_UNDEF && type != R_ARM_GOT32 &&
type != R_ARM_GOTOFF && type != R_ARM_GOTPC &&
type != R_ARM_PLT32)
break;
if (!s1->got)
build_got(s1);
if (type != R_ARM_GOTOFF && type != R_ARM_GOTPC
&& (sym->st_shndx == SHN_UNDEF
|| s1->output_type == TCC_OUTPUT_MEMORY)) {
unsigned long ofs;
/* look at the symbol got offset. If none, then add one */
if (type == R_ARM_GOT32 || type == R_ARM_MOVT_ABS ||
type == R_ARM_MOVW_ABS_NC ||
type == R_ARM_THM_MOVT_ABS ||
type == R_ARM_THM_MOVW_ABS_NC || type == R_ARM_ABS32 ||
type == R_ARM_REL32)
reloc_type = R_ARM_GLOB_DAT;
else
reloc_type = R_ARM_JUMP_SLOT;
ofs = put_got_entry(s1, reloc_type, sym->st_size,
sym->st_info, sym_index);
#ifdef DEBUG_RELOC
printf ("maybegot: %s, %d, %d --> ofs=0x%x\n",
(char *) symtab_section->link->data + sym->st_name,
type, sym->st_shndx, ofs);
#endif
if (type == R_ARM_PC24 || type == R_ARM_CALL ||
type == R_ARM_JUMP24 || type == R_ARM_PLT32) {
addr_t *ptr = (addr_t*)(s1->sections[s->sh_info]->data
+ rel->r_offset);
/* x must be signed! */
int x = *ptr & 0xffffff;
x = (x << 8) >> 8;
x <<= 2;
x += ofs;
x >>= 2;
#ifdef DEBUG_RELOC
printf ("insn=0x%x --> 0x%x (x==0x%x)\n", *ptr,
(*ptr & 0xff000000) | x, x);
#endif
*ptr = (*ptr & 0xff000000) | x;
}
}
break;
case R_ARM_THM_JUMP24:
sym_index = ELFW(R_SYM)(rel->r_info);
sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
/* We are relocating a jump from thumb code to arm code */
if (sym->st_shndx != SHN_UNDEF && !(sym->st_value & 1)) {
int index;
uint8_t *p;
char *name, buf[1024];
Section *text_section;
name = (char *) symtab_section->link->data + sym->st_name;
text_section = s1->sections[sym->st_shndx];
/* Modify reloc to target a thumb stub to switch to ARM */
snprintf(buf, sizeof(buf), "%s_from_thumb", name);
index = put_elf_sym(symtab_section,
text_section->data_offset + 1,
sym->st_size, sym->st_info, 0,
sym->st_shndx, buf);
rel->r_info = ELFW(R_INFO)(index, type);
/* Create a thumb stub fonction to switch to ARM mode */
put_elf_reloc(symtab_section, text_section,
text_section->data_offset + 4, R_ARM_JUMP24,
sym_index);
p = section_ptr_add(text_section, 8);
write32le(p, 0x4778); /* bx pc */
write32le(p+2, 0x46c0); /* nop */
write32le(p+4, 0xeafffffe); /* b $sym */
}
#elif defined(TCC_TARGET_ARM64)
//xx Other cases may be required here:
case R_AARCH64_ADR_GOT_PAGE:
case R_AARCH64_LD64_GOT_LO12_NC:
if (!s1->got)
build_got(s1);
sym_index = ELFW(R_SYM)(rel->r_info);
sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
reloc_type = R_AARCH64_GLOB_DAT;
put_got_entry(s1, reloc_type, sym->st_size, sym->st_info,
sym_index);
break;
case R_AARCH64_JUMP26:
case R_AARCH64_CALL26:
if (!s1->got)
build_got(s1);
sym_index = ELFW(R_SYM)(rel->r_info);
sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
if (sym->st_shndx == SHN_UNDEF ||
s1->output_type == TCC_OUTPUT_MEMORY) {
unsigned long ofs;
reloc_type = R_AARCH64_JUMP_SLOT;
ofs = put_got_entry(s1, reloc_type, sym->st_size,
sym->st_info, sym_index);
/* We store the place of the generated PLT slot
in our addend. */
rel->r_addend += ofs;
}
break;
#elif defined(TCC_TARGET_C67)
case R_C60_GOT32:
case R_C60_GOTOFF:
case R_C60_GOTPC:
case R_C60_PLT32:
if (!s1->got)
build_got(s1);
if (type == R_C60_GOT32 || type == R_C60_PLT32) {
sym_index = ELFW(R_SYM)(rel->r_info);
sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
/* look at the symbol got offset. If none, then add one */
if (type == R_C60_GOT32)
reloc_type = R_C60_GLOB_DAT;
else
reloc_type = R_C60_JMP_SLOT;
put_got_entry(s1, reloc_type, sym->st_size, sym->st_info,
sym_index);
}
break;
#elif defined(TCC_TARGET_X86_64)
case R_X86_64_32:
case R_X86_64_32S:
case R_X86_64_64:
case R_X86_64_PC32:
case R_X86_64_GOT32:
case R_X86_64_GOTTPOFF:
case R_X86_64_GOTPCREL:
case R_X86_64_GOTPCRELX:
case R_X86_64_REX_GOTPCRELX:
case R_X86_64_PLT32:
sym_index = ELFW(R_SYM)(rel->r_info);
sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
if ((type == R_X86_64_32 || type == R_X86_64_32S ||
type == R_X86_64_64 || type == R_X86_64_PC32) &&
sym->st_shndx != SHN_UNDEF)
break;
if (type == R_X86_64_PLT32 &&
ELFW(ST_VISIBILITY)(sym->st_other) != STV_DEFAULT) {
rel->r_info = ELFW(R_INFO)(sym_index, R_X86_64_PC32);
break;
}
if (!s1->got)
build_got(s1);
if (type != R_X86_64_GOTTPOFF) {
unsigned long ofs;
/* look at the symbol got offset. If none, then add one */
if (type == R_X86_64_GOT32 || type == R_X86_64_GOTPCREL ||
type == R_X86_64_GOTPCRELX ||
type == R_X86_64_REX_GOTPCRELX ||
type == R_X86_64_32 || type == R_X86_64_32S ||
type == R_X86_64_64)
reloc_type = R_X86_64_GLOB_DAT;
else
reloc_type = R_X86_64_JUMP_SLOT;
ofs = put_got_entry(s1, reloc_type, sym->st_size,
sym->st_info, sym_index);
if (type == R_X86_64_PLT32)
/* We store the place of the generated PLT slot
in our addend. */
rel->r_addend += ofs;
}
break;
#else
#error unsupported CPU
#endif
default:
break;
#ifdef TCC_TARGET_X86_64
if (type == R_X86_64_PLT32 &&
ELFW(ST_VISIBILITY)(sym->st_other) != STV_DEFAULT) {
rel->r_info = ELFW(R_INFO)(sym_index, R_X86_64_PC32);
continue;
}
#endif
if (!s1->got)
build_got(s1);
if (relocs_info[type].gotplt_entry == BUILD_GOT_ONLY)
continue;
if (relocs_info[type].code_reloc)
reloc_type = R_JMP_SLOT;
else
reloc_type = R_GLOB_DAT;
ofs = put_got_entry(s1, reloc_type, sym->st_size, sym->st_info,
sym_index);
#ifdef DEBUG_RELOC
printf ("maybegot: %s, %d, %d --> ofs=0x%x\n",
(char *) symtab_section->link->data + sym->st_name, type,
sym->st_shndx, ofs);
#endif
#if defined (TCC_TARGET_X86_64) || defined(TCC_TARGET_ARM64)
/* We store the place of the generated PLT slot in our addend. */
if (relocs_info[type].pltoff_addend)
rel->r_addend += ofs;
#elif defined (TCC_TARGET_ARM)
if (type == R_ARM_PC24 || type == R_ARM_CALL ||
type == R_ARM_JUMP24 || type == R_ARM_PLT32) {
addr_t *ptr = (addr_t*)(s1->sections[s->sh_info]->data
+ rel->r_offset);
/* x must be signed! */
int x = *ptr & 0xffffff;
x = (x << 8) >> 8;
x <<= 2;
x += ofs;
x >>= 2;
#ifdef DEBUG_RELOC
printf ("insn=0x%x --> 0x%x (x==0x%x)\n", *ptr,
(*ptr & 0xff000000) | x, x);
#endif
*ptr = (*ptr & 0xff000000) | x;
}
#endif
}
}
}