Alien-TinyCCx
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src/tccelf.c view on Meta::CPAN
} else if (s1->dynsym) {
/* if dynamic symbol exist, then use it */
sym_index = find_elf_sym(s1->dynsym, name);
if (sym_index) {
esym = &((ElfW(Sym) *)s1->dynsym->data)[sym_index];
sym->st_value = esym->st_value;
goto found;
}
}
/* XXX: _fp_hw seems to be part of the ABI, so we ignore
it */
if (!strcmp(name, "_fp_hw"))
goto found;
/* only weak symbols are accepted to be undefined. Their
value is zero */
sym_bind = ELFW(ST_BIND)(sym->st_info);
if (sym_bind == STB_WEAK) {
sym->st_value = 0;
} else {
tcc_error_noabort("undefined symbol '%s'", name);
}
} else if (sh_num < SHN_LORESERVE) {
/* add section base */
sym->st_value += s1->sections[sym->st_shndx]->sh_addr;
}
found: ;
}
}
/* relocate a given section (CPU dependent) by applying the relocations
in the associated relocation section */
ST_FUNC void relocate_section(TCCState *s1, Section *s)
{
Section *sr = s->reloc;
ElfW_Rel *rel;
ElfW(Sym) *sym;
int type, sym_index;
unsigned char *ptr;
addr_t val, addr;
#if defined TCC_TARGET_I386 || defined TCC_TARGET_X86_64
ElfW_Rel *qrel = (ElfW_Rel *) sr->data; /* ptr to next reloc entry reused */
int esym_index;
#endif
for_each_elem(sr, 0, rel, ElfW_Rel) {
ptr = s->data + rel->r_offset;
sym_index = ELFW(R_SYM)(rel->r_info);
sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
val = sym->st_value;
#if defined(TCC_TARGET_ARM64) || defined(TCC_TARGET_X86_64)
val += rel->r_addend;
#endif
type = ELFW(R_TYPE)(rel->r_info);
addr = s->sh_addr + rel->r_offset;
/* CPU specific */
switch(type) {
#if defined(TCC_TARGET_I386)
case R_386_32:
if (s1->output_type == TCC_OUTPUT_DLL) {
esym_index = s1->symtab_to_dynsym[sym_index];
qrel->r_offset = rel->r_offset;
if (esym_index) {
qrel->r_info = ELFW(R_INFO)(esym_index, R_386_32);
qrel++;
break;
} else {
qrel->r_info = ELFW(R_INFO)(0, R_386_RELATIVE);
qrel++;
}
}
add32le(ptr, val);
break;
case R_386_PC32:
if (s1->output_type == TCC_OUTPUT_DLL) {
/* DLL relocation */
esym_index = s1->symtab_to_dynsym[sym_index];
if (esym_index) {
qrel->r_offset = rel->r_offset;
qrel->r_info = ELFW(R_INFO)(esym_index, R_386_PC32);
qrel++;
break;
}
}
add32le(ptr, val - addr);
break;
case R_386_PLT32:
add32le(ptr, val - addr);
break;
case R_386_GLOB_DAT:
case R_386_JMP_SLOT:
write32le(ptr, val);
break;
case R_386_GOTPC:
add32le(ptr, s1->got->sh_addr - addr);
break;
case R_386_GOTOFF:
add32le(ptr, val - s1->got->sh_addr);
break;
case R_386_GOT32:
case R_386_GOT32X:
/* we load the got offset */
add32le(ptr, s1->sym_attrs[sym_index].got_offset);
break;
case R_386_16:
if (s1->output_format != TCC_OUTPUT_FORMAT_BINARY) {
output_file:
tcc_error("can only produce 16-bit binary files");
}
write16le(ptr, read16le(ptr) + val);
break;
case R_386_PC16:
if (s1->output_format != TCC_OUTPUT_FORMAT_BINARY)
goto output_file;
write16le(ptr, read16le(ptr) + val - addr);
break;
#ifdef TCC_TARGET_PE
case R_386_RELATIVE: /* handled in pe_relocate_rva() */
break;
#endif
case R_386_COPY:
/* This reloction must copy initialized data from the library
to the program .bss segment. Currently made like for ARM
(to remove noise of defaukt case). Is this true?
*/
break;
default:
fprintf(stderr,"FIXME: handle reloc type %d at %x [%p] to %x\n",
type, (unsigned)addr, ptr, (unsigned)val);
break;
#elif defined(TCC_TARGET_ARM)
case R_ARM_PC24:
case R_ARM_CALL:
case R_ARM_JUMP24:
case R_ARM_PLT32:
{
int x, is_thumb, is_call, h, blx_avail, is_bl, th_ko;
x = (*(int *) ptr) & 0xffffff;
if (sym->st_shndx == SHN_UNDEF
|| s1->output_type == TCC_OUTPUT_MEMORY)
val = s1->plt->sh_addr;
#ifdef DEBUG_RELOC
printf ("reloc %d: x=0x%x val=0x%x ", type, x, val);
#endif
(*(int *)ptr) &= 0xff000000;
if (x & 0x800000)
x -= 0x1000000;
x <<= 2;
blx_avail = (TCC_ARM_VERSION >= 5);
is_thumb = val & 1;
is_bl = (*(unsigned *) ptr) >> 24 == 0xeb;
is_call = (type == R_ARM_CALL || (type == R_ARM_PC24 && is_bl));
x += val - addr;
#ifdef DEBUG_RELOC
printf (" newx=0x%x name=%s\n", x,
(char *) symtab_section->link->data + sym->st_name);
#endif
h = x & 2;
th_ko = (x & 3) && (!blx_avail || !is_call);
if (th_ko || x >= 0x2000000 || x < -0x2000000)
tcc_error("can't relocate value at %x,%d",addr, type);
x >>= 2;
x &= 0xffffff;
/* Only reached if blx is avail and it is a call */
if (is_thumb) {
x |= h << 24;
(*(int *)ptr) = 0xfa << 24; /* bl -> blx */
}
(*(int *) ptr) |= x;
}
break;
/* Since these relocations only concern Thumb-2 and blx instruction was
introduced before Thumb-2, we can assume blx is available and not
guard its use */
case R_ARM_THM_PC22:
case R_ARM_THM_JUMP24:
{
int x, hi, lo, s, j1, j2, i1, i2, imm10, imm11;
int to_thumb, is_call, to_plt, blx_bit = 1 << 12;
Section *plt;
/* weak reference */
if (sym->st_shndx == SHN_UNDEF &&
ELFW(ST_BIND)(sym->st_info) == STB_WEAK)
break;
/* Get initial offset */
hi = (*(uint16_t *)ptr);
lo = (*(uint16_t *)(ptr+2));
s = (hi >> 10) & 1;
j1 = (lo >> 13) & 1;
j2 = (lo >> 11) & 1;
i1 = (j1 ^ s) ^ 1;
i2 = (j2 ^ s) ^ 1;
imm10 = hi & 0x3ff;
imm11 = lo & 0x7ff;
x = (s << 24) | (i1 << 23) | (i2 << 22) |
(imm10 << 12) | (imm11 << 1);
if (x & 0x01000000)
x -= 0x02000000;
src/tccelf.c view on Meta::CPAN
break;
case R_ARM_GLOB_DAT:
case R_ARM_JUMP_SLOT:
*(addr_t *)ptr = val;
break;
case R_ARM_NONE:
/* Nothing to do. Normally used to indicate a dependency
on a certain symbol (like for exception handling under EABI). */
break;
#ifdef TCC_TARGET_PE
case R_ARM_RELATIVE: /* handled in pe_relocate_rva() */
break;
#endif
default:
fprintf(stderr,"FIXME: handle reloc type %x at %x [%p] to %x\n",
type, (unsigned)addr, ptr, (unsigned)val);
break;
#elif defined(TCC_TARGET_ARM64)
case R_AARCH64_ABS64:
write64le(ptr, val);
break;
case R_AARCH64_ABS32:
write32le(ptr, val);
break;
case R_AARCH64_PREL32:
write32le(ptr, val - addr);
break;
case R_AARCH64_MOVW_UABS_G0_NC:
write32le(ptr, ((read32le(ptr) & 0xffe0001f) |
(val & 0xffff) << 5));
break;
case R_AARCH64_MOVW_UABS_G1_NC:
write32le(ptr, ((read32le(ptr) & 0xffe0001f) |
(val >> 16 & 0xffff) << 5));
break;
case R_AARCH64_MOVW_UABS_G2_NC:
write32le(ptr, ((read32le(ptr) & 0xffe0001f) |
(val >> 32 & 0xffff) << 5));
break;
case R_AARCH64_MOVW_UABS_G3:
write32le(ptr, ((read32le(ptr) & 0xffe0001f) |
(val >> 48 & 0xffff) << 5));
break;
case R_AARCH64_ADR_PREL_PG_HI21: {
uint64_t off = (val >> 12) - (addr >> 12);
if ((off + ((uint64_t)1 << 20)) >> 21)
tcc_error("R_AARCH64_ADR_PREL_PG_HI21 relocation failed");
write32le(ptr, ((read32le(ptr) & 0x9f00001f) |
(off & 0x1ffffc) << 3 | (off & 3) << 29));
break;
}
case R_AARCH64_ADD_ABS_LO12_NC:
write32le(ptr, ((read32le(ptr) & 0xffc003ff) |
(val & 0xfff) << 10));
break;
case R_AARCH64_JUMP26:
case R_AARCH64_CALL26:
/* This check must match the one in build_got_entries, testing
if we really need a PLT slot. */
if (sym->st_shndx == SHN_UNDEF ||
s1->output_type == TCC_OUTPUT_MEMORY)
/* We've put the PLT slot offset into r_addend when generating
it, and that's what we must use as relocation value (adjusted
by section offset of course). */
val = s1->plt->sh_addr + rel->r_addend;
#ifdef DEBUG_RELOC
printf ("reloc %d @ 0x%lx: val=0x%lx name=%s\n", type, addr, val,
(char *) symtab_section->link->data + sym->st_name);
#endif
if (((val - addr) + ((uint64_t)1 << 27)) & ~(uint64_t)0xffffffc)
{
tcc_error("R_AARCH64_(JUMP|CALL)26 relocation failed (val=%lx, addr=%lx)", addr, val);
}
write32le(ptr, (0x14000000 |
(uint32_t)(type == R_AARCH64_CALL26) << 31 |
((val - addr) >> 2 & 0x3ffffff)));
break;
case R_AARCH64_ADR_GOT_PAGE: {
uint64_t off =
(((s1->got->sh_addr +
s1->sym_attrs[sym_index].got_offset) >> 12) - (addr >> 12));
if ((off + ((uint64_t)1 << 20)) >> 21)
tcc_error("R_AARCH64_ADR_GOT_PAGE relocation failed");
write32le(ptr, ((read32le(ptr) & 0x9f00001f) |
(off & 0x1ffffc) << 3 | (off & 3) << 29));
break;
}
case R_AARCH64_LD64_GOT_LO12_NC:
write32le(ptr,
((read32le(ptr) & 0xfff803ff) |
((s1->got->sh_addr +
s1->sym_attrs[sym_index].got_offset) & 0xff8) << 7));
break;
case R_AARCH64_COPY:
break;
case R_AARCH64_GLOB_DAT:
case R_AARCH64_JUMP_SLOT:
/* They don't need addend */
#ifdef DEBUG_RELOC
printf ("reloc %d @ 0x%lx: val=0x%lx name=%s\n", type, addr,
val - rel->r_addend,
(char *) symtab_section->link->data + sym->st_name);
#endif
write64le(ptr, val - rel->r_addend);
break;
default:
fprintf(stderr, "FIXME: handle reloc type %x at %x [%p] to %x\n",
type, (unsigned)addr, ptr, (unsigned)val);
break;
#elif defined(TCC_TARGET_C67)
case R_C60_32:
*(int *)ptr += val;
break;
case R_C60LO16:
{
uint32_t orig;
/* put the low 16 bits of the absolute address
add to what is already there */
orig = ((*(int *)(ptr )) >> 7) & 0xffff;
orig |= (((*(int *)(ptr+4)) >> 7) & 0xffff) << 16;
/* patch both at once - assumes always in pairs Low - High */
*(int *) ptr = (*(int *) ptr & (~(0xffff << 7)) ) | (((val+orig) & 0xffff) << 7);
*(int *)(ptr+4) = (*(int *)(ptr+4) & (~(0xffff << 7)) ) | ((((val+orig)>>16) & 0xffff) << 7);
}
break;
case R_C60HI16:
break;
default:
fprintf(stderr,"FIXME: handle reloc type %x at %x [%p] to %x\n",
type, (unsigned)addr, ptr, (unsigned)val);
break;
#elif defined(TCC_TARGET_X86_64)
case R_X86_64_64:
if (s1->output_type == TCC_OUTPUT_DLL) {
esym_index = s1->symtab_to_dynsym[sym_index];
qrel->r_offset = rel->r_offset;
if (esym_index) {
qrel->r_info = ELFW(R_INFO)(esym_index, R_X86_64_64);
qrel->r_addend = rel->r_addend;
qrel++;
break;
} else {
qrel->r_info = ELFW(R_INFO)(0, R_X86_64_RELATIVE);
qrel->r_addend = read64le(ptr) + val;
qrel++;
}
}
add64le(ptr, val);
break;
case R_X86_64_32:
case R_X86_64_32S:
if (s1->output_type == TCC_OUTPUT_DLL) {
/* XXX: this logic may depend on TCC's codegen
now TCC uses R_X86_64_32 even for a 64bit pointer */
qrel->r_info = ELFW(R_INFO)(0, R_X86_64_RELATIVE);
/* Use sign extension! */
qrel->r_addend = (int)read32le(ptr) + val;
qrel++;
}
add32le(ptr, val);
break;
case R_X86_64_PC32:
if (s1->output_type == TCC_OUTPUT_DLL) {
/* DLL relocation */
esym_index = s1->symtab_to_dynsym[sym_index];
if (esym_index) {
qrel->r_offset = rel->r_offset;
qrel->r_info = ELFW(R_INFO)(esym_index, R_X86_64_PC32);
/* Use sign extension! */
qrel->r_addend = (int)read32le(ptr) + rel->r_addend;
qrel++;
break;
}
}
goto plt32pc32;
case R_X86_64_PLT32:
/* We've put the PLT slot offset into r_addend when generating
it, and that's what we must use as relocation value (adjusted
by section offset of course). */
val = s1->plt->sh_addr + rel->r_addend;
/* fallthrough. */
plt32pc32:
{
long long diff;
diff = (long long)val - addr;
if (diff < -2147483648LL || diff > 2147483647LL) {
tcc_error("internal error: relocation failed");
}
add32le(ptr, diff);
}
break;
case R_X86_64_GLOB_DAT:
case R_X86_64_JUMP_SLOT:
/* They don't need addend */
write64le(ptr, val - rel->r_addend);
break;
case R_X86_64_GOTPCREL:
case R_X86_64_GOTPCRELX:
case R_X86_64_REX_GOTPCRELX:
add32le(ptr, s1->got->sh_addr - addr
+ s1->sym_attrs[sym_index].got_offset - 4);
break;
case R_X86_64_GOTTPOFF:
add32le(ptr, val - s1->got->sh_addr);
break;
case R_X86_64_GOT32:
/* we load the got offset */
add32le(ptr, s1->sym_attrs[sym_index].got_offset);
break;
#ifdef TCC_TARGET_PE
case R_X86_64_RELATIVE: /* handled in pe_relocate_rva() */
break;
#endif
#else
#error unsupported processor
#endif
}
}
/* if the relocation is allocated, we change its symbol table */
if (sr->sh_flags & SHF_ALLOC)
src/tccelf.c view on Meta::CPAN
and 'info' can be modifed if more precise info comes from the DLL.
Returns offset of GOT or PLT slot. */
static unsigned long put_got_entry(TCCState *s1,
int reloc_type, unsigned long size, int info,
int sym_index)
{
int index, need_plt_entry;
const char *name;
ElfW(Sym) *sym;
unsigned long offset;
int *ptr;
struct sym_attr *symattr;
if (!s1->got)
build_got(s1);
need_plt_entry =
#ifdef TCC_TARGET_X86_64
(reloc_type == R_X86_64_JUMP_SLOT);
#elif defined(TCC_TARGET_I386)
(reloc_type == R_386_JMP_SLOT);
#elif defined(TCC_TARGET_ARM)
(reloc_type == R_ARM_JUMP_SLOT);
#elif defined(TCC_TARGET_ARM64)
(reloc_type == R_AARCH64_JUMP_SLOT);
#else
0;
#endif
if (need_plt_entry && !s1->plt) {
/* add PLT */
s1->plt = new_section(s1, ".plt", SHT_PROGBITS,
SHF_ALLOC | SHF_EXECINSTR);
s1->plt->sh_entsize = 4;
}
/* If a got/plt entry already exists for that symbol, no need to add one */
if (sym_index < s1->nb_sym_attrs) {
if (need_plt_entry && s1->sym_attrs[sym_index].plt_offset)
return s1->sym_attrs[sym_index].plt_offset;
else if (!need_plt_entry && s1->sym_attrs[sym_index].got_offset)
return s1->sym_attrs[sym_index].got_offset;
}
symattr = alloc_sym_attr(s1, sym_index);
/* Only store the GOT offset if it's not generated for the PLT entry. */
if (!need_plt_entry)
symattr->got_offset = s1->got->data_offset;
sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
name = (char *) symtab_section->link->data + sym->st_name;
offset = sym->st_value;
#if defined(TCC_TARGET_I386) || defined(TCC_TARGET_X86_64)
if (need_plt_entry) {
Section *plt;
uint8_t *p;
int modrm;
unsigned long relofs;
#if defined(TCC_OUTPUT_DLL_WITH_PLT)
modrm = 0x25;
#else
/* if we build a DLL, we add a %ebx offset */
if (s1->output_type == TCC_OUTPUT_DLL)
modrm = 0xa3;
else
modrm = 0x25;
#endif
/* add a PLT entry */
plt = s1->plt;
if (plt->data_offset == 0) {
/* first plt entry */
p = section_ptr_add(plt, 16);
p[0] = 0xff; /* pushl got + PTR_SIZE */
p[1] = modrm + 0x10;
write32le(p + 2, PTR_SIZE);
p[6] = 0xff; /* jmp *(got + PTR_SIZE * 2) */
p[7] = modrm;
write32le(p + 8, PTR_SIZE * 2);
}
/* The PLT slot refers to the relocation entry it needs
via offset. The reloc entry is created below, so its
offset is the current data_offset. */
relofs = s1->got->reloc ? s1->got->reloc->data_offset : 0;
symattr->plt_offset = plt->data_offset;
p = section_ptr_add(plt, 16);
p[0] = 0xff; /* jmp *(got + x) */
p[1] = modrm;
write32le(p + 2, s1->got->data_offset);
p[6] = 0x68; /* push $xxx */
#ifdef TCC_TARGET_X86_64
/* On x86-64, the relocation is referred to by _index_. */
write32le(p + 7, relofs / sizeof (ElfW_Rel));
#else
write32le(p + 7, relofs);
#endif
p[11] = 0xe9; /* jmp plt_start */
write32le(p + 12, -(plt->data_offset));
/* If this was an UNDEF symbol set the offset in the
dynsymtab to the PLT slot, so that PC32 relocs to it
can be resolved. */
if (sym->st_shndx == SHN_UNDEF)
offset = plt->data_offset - 16;
}
#elif defined(TCC_TARGET_ARM)
if (need_plt_entry) {
Section *plt;
uint8_t *p;
/* if we build a DLL, we add a %ebx offset */
if (s1->output_type == TCC_OUTPUT_DLL)
tcc_error("DLLs unimplemented!");
/* add a PLT entry */
plt = s1->plt;
if (plt->data_offset == 0) {
/* first plt entry */
p = section_ptr_add(plt, 16);
write32le(p, 0xe52de004); /* push {lr} */
write32le(p+4, 0xe59fe010); /* ldr lr, [pc, #16] */
write32le(p+8, 0xe08fe00e); /* add lr, pc, lr */
write32le(p+12, 0xe5bef008); /* ldr pc, [lr, #8]! */
}
symattr->plt_offset = plt->data_offset;
if (symattr->plt_thumb_stub) {
p = section_ptr_add(plt, 20);
write32le(p, 0x4778); /* bx pc */
write32le(p+2, 0x46c0); /* nop */
p += 4;
} else
p = section_ptr_add(plt, 16);
write32le(p, 0xe59fc004); /* ldr ip, [pc, #4] ; GOT entry offset */
write32le(p+4, 0xe08fc00c); /* add ip, pc, ip ; addr of GOT entry */
write32le(p+8, 0xe59cf000); /* ldr pc, [ip] ; jump to GOT entry */
write32le(p+12, s1->got->data_offset); /* GOT entry off once patched */
/* the symbol is modified so that it will be relocated to
the PLT */
if (sym->st_shndx == SHN_UNDEF)
offset = plt->data_offset - 16;
}
#elif defined(TCC_TARGET_ARM64)
if (need_plt_entry) {
Section *plt;
uint8_t *p;
if (s1->output_type == TCC_OUTPUT_DLL)
tcc_error("DLLs unimplemented!");
plt = s1->plt;
if (plt->data_offset == 0)
section_ptr_add(plt, 32);
symattr->plt_offset = plt->data_offset;
p = section_ptr_add(plt, 16);
write32le(p, s1->got->data_offset);
write32le(p + 4, (uint64_t)s1->got->data_offset >> 32);
if (sym->st_shndx == SHN_UNDEF)
offset = plt->data_offset - 16;
}
#elif defined(TCC_TARGET_C67)
if (s1->dynsym) {
tcc_error("C67 got not implemented");
}
#else
#error unsupported CPU
#endif
if (s1->dynsym) {
/* XXX This might generate multiple syms for name. */
index = put_elf_sym(s1->dynsym, offset,
size, info, 0, sym->st_shndx, name);
/* Create the relocation (it's against the GOT for PLT
and GOT relocs). */
put_elf_reloc(s1->dynsym, s1->got,
s1->got->data_offset,
reloc_type, index);
} else {
/* Without .dynsym (i.e. static link or memory output) we
still need relocs against the generated got, so as to fill
the entries with the symbol values (determined later). */
put_elf_reloc(symtab_section, s1->got,
s1->got->data_offset,
reloc_type, sym_index);
}
/* And now create the GOT slot itself. */
ptr = section_ptr_add(s1->got, PTR_SIZE);
*ptr = 0;
if (need_plt_entry)
return symattr->plt_offset;
else
return symattr->got_offset;
}
/* build GOT and PLT entries */
ST_FUNC void build_got_entries(TCCState *s1)
{
Section *s;
ElfW_Rel *rel;
ElfW(Sym) *sym;
int i, type, reloc_type, sym_index;
for(i = 1; i < s1->nb_sections; i++) {
s = s1->sections[i];
if (s->sh_type != SHT_RELX)
continue;
/* no need to handle got relocations */
if (s->link != symtab_section)
continue;
for_each_elem(s, 0, rel, ElfW_Rel) {
type = ELFW(R_TYPE)(rel->r_info);
switch(type) {
#if defined(TCC_TARGET_I386)
case R_386_GOT32:
case R_386_GOT32X:
case R_386_GOTOFF:
case R_386_GOTPC:
case R_386_PLT32:
if (!s1->got)
build_got(s1);
if (type == R_386_GOT32 || type == R_386_GOT32X ||
type == R_386_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_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_GOT32:
case R_ARM_GOTOFF:
case R_ARM_GOTPC:
case R_ARM_PLT32:
if (!s1->got)
build_got(s1);
sym_index = ELFW(R_SYM)(rel->r_info);
sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
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)
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_GOT32) {
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_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_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);
sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
}
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_PLT32) {
unsigned long ofs;
/* look at the symbol got offset. If none, then add one */
if (type == R_X86_64_PLT32)
reloc_type = R_X86_64_JUMP_SLOT;
else
reloc_type = R_X86_64_GLOB_DAT;
ofs = put_got_entry(s1, reloc_type, sym->st_size,
sym->st_info, sym_index);
src/tccelf.c view on Meta::CPAN
dyn = section_ptr_add(dynamic, sizeof(ElfW(Dyn)));
dyn->d_tag = dt;
dyn->d_un.d_val = val;
}
#ifndef TCC_TARGET_PE
static void add_init_array_defines(TCCState *s1, const char *section_name)
{
Section *s;
long end_offset;
char sym_start[1024];
char sym_end[1024];
snprintf(sym_start, sizeof(sym_start), "__%s_start", section_name + 1);
snprintf(sym_end, sizeof(sym_end), "__%s_end", section_name + 1);
s = find_section(s1, section_name);
if (!s) {
end_offset = 0;
s = data_section;
} else {
end_offset = s->data_offset;
}
add_elf_sym(symtab_section,
0, 0,
ELFW(ST_INFO)(STB_GLOBAL, STT_NOTYPE), 0,
s->sh_num, sym_start);
add_elf_sym(symtab_section,
end_offset, 0,
ELFW(ST_INFO)(STB_GLOBAL, STT_NOTYPE), 0,
s->sh_num, sym_end);
}
#endif
static int tcc_add_support(TCCState *s1, const char *filename)
{
char buf[1024];
snprintf(buf, sizeof(buf), "%s/"TCC_ARCH_DIR"%s", s1->tcc_lib_path, filename);
return tcc_add_file(s1, buf);
}
ST_FUNC void tcc_add_bcheck(TCCState *s1)
{
#ifdef CONFIG_TCC_BCHECK
addr_t *ptr;
int sym_index;
if (0 == s1->do_bounds_check)
return;
/* XXX: add an object file to do that */
ptr = section_ptr_add(bounds_section, sizeof(*ptr));
*ptr = 0;
add_elf_sym(symtab_section, 0, 0,
ELFW(ST_INFO)(STB_GLOBAL, STT_NOTYPE), 0,
bounds_section->sh_num, "__bounds_start");
/* pull bcheck.o from libtcc1.a */
sym_index = add_elf_sym(symtab_section, 0, 0,
ELFW(ST_INFO)(STB_GLOBAL, STT_NOTYPE), 0,
SHN_UNDEF, "__bound_init");
if (s1->output_type != TCC_OUTPUT_MEMORY) {
/* add 'call __bound_init()' in .init section */
Section *init_section = find_section(s1, ".init");
unsigned char *pinit = section_ptr_add(init_section, 5);
pinit[0] = 0xe8;
write32le(pinit + 1, -4);
put_elf_reloc(symtab_section, init_section,
init_section->data_offset - 4, R_386_PC32, sym_index);
/* R_386_PC32 = R_X86_64_PC32 = 2 */
}
#endif
}
/* add tcc runtime libraries */
ST_FUNC void tcc_add_runtime(TCCState *s1)
{
tcc_add_bcheck(s1);
tcc_add_pragma_libs(s1);
/* add libc */
if (!s1->nostdlib) {
tcc_add_library_err(s1, "c");
#ifdef CONFIG_USE_LIBGCC
if (!s1->static_link) {
tcc_add_file(s1, TCC_LIBGCC);
}
#endif
tcc_add_support(s1, "libtcc1.a");
/* add crt end if not memory output */
if (s1->output_type != TCC_OUTPUT_MEMORY)
tcc_add_crt(s1, "crtn.o");
}
}
/* add various standard linker symbols (must be done after the
sections are filled (for example after allocating common
symbols)) */
ST_FUNC void tcc_add_linker_symbols(TCCState *s1)
{
char buf[1024];
int i;
Section *s;
add_elf_sym(symtab_section,
text_section->data_offset, 0,
ELFW(ST_INFO)(STB_GLOBAL, STT_NOTYPE), 0,
text_section->sh_num, "_etext");
add_elf_sym(symtab_section,
data_section->data_offset, 0,
ELFW(ST_INFO)(STB_GLOBAL, STT_NOTYPE), 0,
data_section->sh_num, "_edata");
add_elf_sym(symtab_section,
bss_section->data_offset, 0,
ELFW(ST_INFO)(STB_GLOBAL, STT_NOTYPE), 0,
bss_section->sh_num, "_end");
#ifndef TCC_TARGET_PE
/* horrible new standard ldscript defines */
add_init_array_defines(s1, ".preinit_array");
add_init_array_defines(s1, ".init_array");
add_init_array_defines(s1, ".fini_array");
#endif
/* add start and stop symbols for sections whose name can be
expressed in C */
for(i = 1; i < s1->nb_sections; i++) {
s = s1->sections[i];
if (s->sh_type == SHT_PROGBITS &&
(s->sh_flags & SHF_ALLOC)) {
const char *p;
int ch;
/* check if section name can be expressed in C */
p = s->name;
for(;;) {
ch = *p;
if (!ch)
break;
if (!isid(ch) && !isnum(ch))
goto next_sec;
p++;
}
snprintf(buf, sizeof(buf), "__start_%s", s->name);
add_elf_sym(symtab_section,
0, 0,
ELFW(ST_INFO)(STB_GLOBAL, STT_NOTYPE), 0,
s->sh_num, buf);
snprintf(buf, sizeof(buf), "__stop_%s", s->name);
add_elf_sym(symtab_section,
s->data_offset, 0,
ELFW(ST_INFO)(STB_GLOBAL, STT_NOTYPE), 0,
src/tccelf.c view on Meta::CPAN
p += 4;
add32le(p + 12, x + s1->plt->data - p);
p += 16;
}
#elif defined(TCC_TARGET_ARM64)
uint64_t plt = s1->plt->sh_addr;
uint64_t got = s1->got->sh_addr;
uint64_t off = (got >> 12) - (plt >> 12);
if ((off + ((uint32_t)1 << 20)) >> 21)
tcc_error("Failed relocating PLT (off=0x%lx, got=0x%lx, plt=0x%lx)", off, got, plt);
write32le(p, 0xa9bf7bf0); // stp x16,x30,[sp,#-16]!
write32le(p + 4, (0x90000010 | // adrp x16,...
(off & 0x1ffffc) << 3 | (off & 3) << 29));
write32le(p + 8, (0xf9400211 | // ldr x17,[x16,#...]
(got & 0xff8) << 7));
write32le(p + 12, (0x91000210 | // add x16,x16,#...
(got & 0xfff) << 10));
write32le(p + 16, 0xd61f0220); // br x17
write32le(p + 20, 0xd503201f); // nop
write32le(p + 24, 0xd503201f); // nop
write32le(p + 28, 0xd503201f); // nop
p += 32;
while (p < p_end) {
uint64_t pc = plt + (p - s1->plt->data);
uint64_t addr = got + read64le(p);
uint64_t off = (addr >> 12) - (pc >> 12);
if ((off + ((uint32_t)1 << 20)) >> 21)
tcc_error("Failed relocating PLT (off=0x%lx, addr=0x%lx, pc=0x%lx)", off, addr, pc);
write32le(p, (0x90000010 | // adrp x16,...
(off & 0x1ffffc) << 3 | (off & 3) << 29));
write32le(p + 4, (0xf9400211 | // ldr x17,[x16,#...]
(addr & 0xff8) << 7));
write32le(p + 8, (0x91000210 | // add x16,x16,#...
(addr & 0xfff) << 10));
write32le(p + 12, 0xd61f0220); // br x17
p += 16;
}
#elif defined(TCC_TARGET_C67)
/* XXX: TODO */
#else
#error unsupported CPU
#endif
}
}
/* Allocate strings for section names and decide if an unallocated section
should be output.
NOTE: the strsec section comes last, so its size is also correct ! */
static void alloc_sec_names(TCCState *s1, int file_type, Section *strsec)
{
int i;
Section *s;
/* Allocate strings for section names */
for(i = 1; i < s1->nb_sections; i++) {
s = s1->sections[i];
s->sh_name = put_elf_str(strsec, s->name);
/* when generating a DLL, we include relocations but we may
patch them */
if (file_type == TCC_OUTPUT_DLL &&
s->sh_type == SHT_RELX &&
!(s->sh_flags & SHF_ALLOC)) {
/* gr: avoid bogus relocs for empty (debug) sections */
if (s1->sections[s->sh_info]->sh_flags & SHF_ALLOC)
prepare_dynamic_rel(s1, s);
else if (s1->do_debug)
s->sh_size = s->data_offset;
} else if (s1->do_debug ||
file_type == TCC_OUTPUT_OBJ ||
(s->sh_flags & SHF_ALLOC) ||
i == (s1->nb_sections - 1)) {
/* we output all sections if debug or object file */
s->sh_size = s->data_offset;
}
}
}
/* Info to be copied in dynamic section */
struct dyn_inf {
Section *dynamic;
Section *dynstr;
unsigned long dyn_rel_off;
addr_t rel_addr;
addr_t rel_size;
#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
addr_t bss_addr;
addr_t bss_size;
#endif
};
/* Assign sections to segments and decide how are sections laid out when loaded
in memory. This function also fills corresponding program headers. */
static int layout_sections(TCCState *s1, ElfW(Phdr) *phdr, int phnum,
Section *interp, Section* strsec,
struct dyn_inf *dyninf, int *sec_order)
{
int i, j, k, file_type, sh_order_index, file_offset;
unsigned long s_align;
long long tmp;
addr_t addr;
ElfW(Phdr) *ph;
Section *s;
file_type = s1->output_type;
sh_order_index = 1;
file_offset = 0;
if (s1->output_format == TCC_OUTPUT_FORMAT_ELF)
file_offset = sizeof(ElfW(Ehdr)) + phnum * sizeof(ElfW(Phdr));
s_align = ELF_PAGE_SIZE;
if (s1->section_align)
s_align = s1->section_align;
if (phnum > 0) {
if (s1->has_text_addr) {
int a_offset, p_offset;
addr = s1->text_addr;
/* we ensure that (addr % ELF_PAGE_SIZE) == file_offset %
ELF_PAGE_SIZE */
a_offset = (int) (addr & (s_align - 1));
p_offset = file_offset & (s_align - 1);
if (a_offset < p_offset)
a_offset += s_align;
file_offset += (a_offset - p_offset);
} else {
if (file_type == TCC_OUTPUT_DLL)
addr = 0;
else
addr = ELF_START_ADDR;
/* compute address after headers */
addr += (file_offset & (s_align - 1));
}
ph = &phdr[0];
/* Leave one program headers for the program interpreter and one for
the program header table itself if needed. These are done later as
they require section layout to be done first. */
if (interp)
ph += 1 + HAVE_PHDR;
/* dynamic relocation table information, for .dynamic section */
dyninf->rel_addr = dyninf->rel_size = 0;
#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
dyninf->bss_addr = dyninf->bss_size = 0;
#endif
for(j = 0; j < 2; j++) {
ph->p_type = PT_LOAD;
if (j == 0)
ph->p_flags = PF_R | PF_X;
else
ph->p_flags = PF_R | PF_W;
ph->p_align = s_align;
/* Decide the layout of sections loaded in memory. This must
be done before program headers are filled since they contain
info about the layout. We do the following ordering: interp,
symbol tables, relocations, progbits, nobits */
/* XXX: do faster and simpler sorting */
for(k = 0; k < 5; k++) {
for(i = 1; i < s1->nb_sections; i++) {
s = s1->sections[i];
/* compute if section should be included */
if (j == 0) {
if ((s->sh_flags & (SHF_ALLOC | SHF_WRITE)) !=
SHF_ALLOC)
continue;
} else {
if ((s->sh_flags & (SHF_ALLOC | SHF_WRITE)) !=
(SHF_ALLOC | SHF_WRITE))
continue;
}
if (s == interp) {
if (k != 0)
continue;
} else if (s->sh_type == SHT_DYNSYM ||
s->sh_type == SHT_STRTAB ||
s->sh_type == SHT_HASH) {
if (k != 1)
continue;
} else if (s->sh_type == SHT_RELX) {
if (k != 2)
continue;
} else if (s->sh_type == SHT_NOBITS) {
if (k != 4)
continue;
} else {
if (k != 3)
continue;
}
sec_order[sh_order_index++] = i;
/* section matches: we align it and add its size */
tmp = addr;
addr = (addr + s->sh_addralign - 1) &
~(s->sh_addralign - 1);
file_offset += (int) ( addr - tmp );
s->sh_offset = file_offset;
s->sh_addr = addr;
/* update program header infos */
if (ph->p_offset == 0) {
ph->p_offset = file_offset;
ph->p_vaddr = addr;
ph->p_paddr = ph->p_vaddr;
}
/* update dynamic relocation infos */
if (s->sh_type == SHT_RELX) {
#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
if (!strcmp(strsec->data + s->sh_name, ".rel.got")) {
dyninf->rel_addr = addr;
dyninf->rel_size += s->sh_size; /* XXX only first rel. */
}
if (!strcmp(strsec->data + s->sh_name, ".rel.bss")) {
dyninf->bss_addr = addr;
dyninf->bss_size = s->sh_size; /* XXX only first rel. */
}
#else
if (dyninf->rel_size == 0)
dyninf->rel_addr = addr;
dyninf->rel_size += s->sh_size;
#endif
}
addr += s->sh_size;
if (s->sh_type != SHT_NOBITS)
file_offset += s->sh_size;
}
}
if (j == 0) {
/* Make the first PT_LOAD segment include the program
headers itself (and the ELF header as well), it'll
come out with same memory use but will make various
tools like binutils strip work better. */
ph->p_offset &= ~(ph->p_align - 1);
ph->p_vaddr &= ~(ph->p_align - 1);
ph->p_paddr &= ~(ph->p_align - 1);
}
ph->p_filesz = file_offset - ph->p_offset;
ph->p_memsz = addr - ph->p_vaddr;
ph++;
if (j == 0) {
if (s1->output_format == TCC_OUTPUT_FORMAT_ELF) {
/* if in the middle of a page, we duplicate the page in
memory so that one copy is RX and the other is RW */
if ((addr & (s_align - 1)) != 0)
addr += s_align;
} else {
addr = (addr + s_align - 1) & ~(s_align - 1);
file_offset = (file_offset + s_align - 1) & ~(s_align - 1);
}
}
}
}
/* all other sections come after */
for(i = 1; i < s1->nb_sections; i++) {
s = s1->sections[i];
if (phnum > 0 && (s->sh_flags & SHF_ALLOC))
continue;
sec_order[sh_order_index++] = i;
file_offset = (file_offset + s->sh_addralign - 1) &
~(s->sh_addralign - 1);
s->sh_offset = file_offset;
if (s->sh_type != SHT_NOBITS)
file_offset += s->sh_size;
}
return file_offset;
}
static void fill_unloadable_phdr(ElfW(Phdr) *phdr, int phnum, Section *interp,
Section *dynamic)
{
ElfW(Phdr) *ph;
/* if interpreter, then add corresponding program header */
if (interp) {
ph = &phdr[0];
if (HAVE_PHDR)
{
int len = phnum * sizeof(ElfW(Phdr));
ph->p_type = PT_PHDR;
ph->p_offset = sizeof(ElfW(Ehdr));
ph->p_vaddr = interp->sh_addr - len;
ph->p_paddr = ph->p_vaddr;
ph->p_filesz = ph->p_memsz = len;
ph->p_flags = PF_R | PF_X;
ph->p_align = 4; /* interp->sh_addralign; */
ph++;
}
ph->p_type = PT_INTERP;
ph->p_offset = interp->sh_offset;
ph->p_vaddr = interp->sh_addr;
ph->p_paddr = ph->p_vaddr;
ph->p_filesz = interp->sh_size;
ph->p_memsz = interp->sh_size;
ph->p_flags = PF_R;
ph->p_align = interp->sh_addralign;
src/tccelf.c view on Meta::CPAN
/* On X86 gdb 7.3 works in any case but gdb 6.6 will crash if SHF_ALLOC
checking is removed */
#else
if (s->reloc && s != s1->got)
/* On X86_64 gdb 7.3 will crash if SHF_ALLOC checking is present */
#endif
relocate_section(s1, s);
}
/* relocate relocation entries if the relocation tables are
allocated in the executable */
for(i = 1; i < s1->nb_sections; i++) {
s = s1->sections[i];
if ((s->sh_flags & SHF_ALLOC) &&
s->sh_type == SHT_RELX) {
relocate_rel(s1, s);
}
}
return 0;
}
/* Create an ELF file on disk.
This function handle ELF specific layout requirements */
static void tcc_output_elf(TCCState *s1, FILE *f, int phnum, ElfW(Phdr) *phdr,
int file_offset, int *sec_order)
{
int i, shnum, offset, size, file_type;
Section *s;
ElfW(Ehdr) ehdr;
ElfW(Shdr) shdr, *sh;
file_type = s1->output_type;
shnum = s1->nb_sections;
memset(&ehdr, 0, sizeof(ehdr));
if (phnum > 0) {
ehdr.e_phentsize = sizeof(ElfW(Phdr));
ehdr.e_phnum = phnum;
ehdr.e_phoff = sizeof(ElfW(Ehdr));
}
/* align to 4 */
file_offset = (file_offset + 3) & -4;
/* fill header */
ehdr.e_ident[0] = ELFMAG0;
ehdr.e_ident[1] = ELFMAG1;
ehdr.e_ident[2] = ELFMAG2;
ehdr.e_ident[3] = ELFMAG3;
ehdr.e_ident[4] = ELFCLASSW;
ehdr.e_ident[5] = ELFDATA2LSB;
ehdr.e_ident[6] = EV_CURRENT;
#if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
ehdr.e_ident[EI_OSABI] = ELFOSABI_FREEBSD;
#endif
#ifdef TCC_TARGET_ARM
#ifdef TCC_ARM_EABI
ehdr.e_ident[EI_OSABI] = 0;
ehdr.e_flags = EF_ARM_EABI_VER4;
if (file_type == TCC_OUTPUT_EXE || file_type == TCC_OUTPUT_DLL)
ehdr.e_flags |= EF_ARM_HASENTRY;
if (s1->float_abi == ARM_HARD_FLOAT)
ehdr.e_flags |= EF_ARM_VFP_FLOAT;
else
ehdr.e_flags |= EF_ARM_SOFT_FLOAT;
#else
ehdr.e_ident[EI_OSABI] = ELFOSABI_ARM;
#endif
#endif
switch(file_type) {
default:
case TCC_OUTPUT_EXE:
ehdr.e_type = ET_EXEC;
ehdr.e_entry = get_elf_sym_addr(s1, "_start", 1);
break;
case TCC_OUTPUT_DLL:
ehdr.e_type = ET_DYN;
ehdr.e_entry = text_section->sh_addr; /* XXX: is it correct ? */
break;
case TCC_OUTPUT_OBJ:
ehdr.e_type = ET_REL;
break;
}
ehdr.e_machine = EM_TCC_TARGET;
ehdr.e_version = EV_CURRENT;
ehdr.e_shoff = file_offset;
ehdr.e_ehsize = sizeof(ElfW(Ehdr));
ehdr.e_shentsize = sizeof(ElfW(Shdr));
ehdr.e_shnum = shnum;
ehdr.e_shstrndx = shnum - 1;
fwrite(&ehdr, 1, sizeof(ElfW(Ehdr)), f);
fwrite(phdr, 1, phnum * sizeof(ElfW(Phdr)), f);
offset = sizeof(ElfW(Ehdr)) + phnum * sizeof(ElfW(Phdr));
sort_syms(s1, symtab_section);
for(i = 1; i < s1->nb_sections; i++) {
s = s1->sections[sec_order[i]];
if (s->sh_type != SHT_NOBITS) {
if (s->sh_type == SHT_DYNSYM)
patch_dynsym_undef(s1, s);
while (offset < s->sh_offset) {
fputc(0, f);
offset++;
}
size = s->sh_size;
if (size)
fwrite(s->data, 1, size, f);
offset += size;
}
}
/* output section headers */
while (offset < ehdr.e_shoff) {
fputc(0, f);
offset++;
}
for(i = 0; i < s1->nb_sections; i++) {
sh = &shdr;
memset(sh, 0, sizeof(ElfW(Shdr)));
s = s1->sections[i];
if (s) {
sh->sh_name = s->sh_name;
sh->sh_type = s->sh_type;
sh->sh_flags = s->sh_flags;
sh->sh_entsize = s->sh_entsize;
sh->sh_info = s->sh_info;
if (s->link)
sh->sh_link = s->link->sh_num;
sh->sh_addralign = s->sh_addralign;
sh->sh_addr = s->sh_addr;
sh->sh_offset = s->sh_offset;
sh->sh_size = s->sh_size;
}
fwrite(sh, 1, sizeof(ElfW(Shdr)), f);
}
}
/* Write an elf, coff or "binary" file */
static int tcc_write_elf_file(TCCState *s1, const char *filename, int phnum,
ElfW(Phdr) *phdr, int file_offset, int *sec_order)
{
int fd, mode, file_type;
FILE *f;
file_type = s1->output_type;
if (file_type == TCC_OUTPUT_OBJ)
mode = 0666;
else
mode = 0777;
unlink(filename);
fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, mode);
if (fd < 0) {
tcc_error_noabort("could not write '%s'", filename);
return -1;
}
f = fdopen(fd, "wb");
if (s1->verbose)
printf("<- %s\n", filename);
#ifdef TCC_TARGET_COFF
if (s1->output_format == TCC_OUTPUT_FORMAT_COFF)
tcc_output_coff(s1, f);
else
#endif
if (s1->output_format == TCC_OUTPUT_FORMAT_ELF)
tcc_output_elf(s1, f, phnum, phdr, file_offset, sec_order);
else
tcc_output_binary(s1, f, sec_order);
fclose(f);
return 0;
}
/* Output an elf, coff or binary file */
/* XXX: suppress unneeded sections */
static int elf_output_file(TCCState *s1, const char *filename)
{
int i, ret, phnum, shnum, file_type, file_offset, *sec_order;
struct dyn_inf dyninf;
ElfW(Phdr) *phdr;
ElfW(Sym) *sym;
Section *strsec, *interp, *dynamic, *dynstr;
file_type = s1->output_type;
s1->nb_errors = 0;
/* if linking, also link in runtime libraries (libc, libgcc, etc.) */
if (file_type != TCC_OUTPUT_OBJ) {
tcc_add_runtime(s1);
}
phdr = NULL;
sec_order = NULL;
interp = dynamic = dynstr = NULL; /* avoid warning */
dyninf.dyn_rel_off = 0; /* avoid warning */
if (file_type != TCC_OUTPUT_OBJ) {
relocate_common_syms();
tcc_add_linker_symbols(s1);
if (!s1->static_link) {
if (file_type == TCC_OUTPUT_EXE) {
char *ptr;
/* allow override the dynamic loader */
const char *elfint = getenv("LD_SO");
if (elfint == NULL)
elfint = DEFAULT_ELFINTERP(s1);
/* add interpreter section only if executable */
interp = new_section(s1, ".interp", SHT_PROGBITS, SHF_ALLOC);
interp->sh_addralign = 1;
ptr = section_ptr_add(interp, 1 + strlen(elfint));
strcpy(ptr, elfint);
}
/* add dynamic symbol table */
s1->dynsym = new_symtab(s1, ".dynsym", SHT_DYNSYM, SHF_ALLOC,
".dynstr",
".hash", SHF_ALLOC);
dynstr = s1->dynsym->link;
/* add dynamic section */
dynamic = new_section(s1, ".dynamic", SHT_DYNAMIC,
SHF_ALLOC | SHF_WRITE);
dynamic->link = dynstr;
dynamic->sh_entsize = sizeof(ElfW(Dyn));
build_got(s1);
if (file_type == TCC_OUTPUT_EXE) {
bind_exe_dynsyms(s1);
if (s1->nb_errors) {
ret = -1;
goto the_end;
}
bind_libs_dynsyms(s1);
} else /* shared library case: simply export all global symbols */
export_global_syms(s1);
build_got_entries(s1);
/* add a list of needed dlls */
for(i = 0; i < s1->nb_loaded_dlls; i++) {
DLLReference *dllref = s1->loaded_dlls[i];
if (dllref->level == 0)
put_dt(dynamic, DT_NEEDED, put_elf_str(dynstr, dllref->name));
}
if (s1->rpath)
put_dt(dynamic, DT_RPATH, put_elf_str(dynstr, s1->rpath));
/* XXX: currently, since we do not handle PIC code, we
must relocate the readonly segments */
if (file_type == TCC_OUTPUT_DLL) {
if (s1->soname)
put_dt(dynamic, DT_SONAME, put_elf_str(dynstr, s1->soname));
put_dt(dynamic, DT_TEXTREL, 0);
}
if (s1->symbolic)
put_dt(dynamic, DT_SYMBOLIC, 0);
/* add necessary space for other entries */
dyninf.dyn_rel_off = dynamic->data_offset;
dynamic->data_offset += sizeof(ElfW(Dyn)) * EXTRA_RELITEMS;
} else {
/* still need to build got entries in case of static link */
build_got_entries(s1);
}
}
/* we add a section for symbols */
strsec = new_section(s1, ".shstrtab", SHT_STRTAB, 0);
put_elf_str(strsec, "");
/* compute number of sections */
shnum = s1->nb_sections;
/* this array is used to reorder sections in the output file */
sec_order = tcc_malloc(sizeof(int) * shnum);
sec_order[0] = 0;
/* compute number of program headers */
switch(file_type) {
default:
case TCC_OUTPUT_OBJ:
phnum = 0;
break;
case TCC_OUTPUT_EXE:
if (!s1->static_link)
phnum = 4 + HAVE_PHDR;
else
phnum = 2;
break;
case TCC_OUTPUT_DLL:
phnum = 3;
break;
}
/* Allocate strings for section names */
alloc_sec_names(s1, file_type, strsec);
/* allocate program segment headers */
phdr = tcc_mallocz(phnum * sizeof(ElfW(Phdr)));
/* compute section to program header mapping */
file_offset = layout_sections(s1, phdr, phnum, interp, strsec, &dyninf,
sec_order);
/* Fill remaining program header and finalize relocation related to dynamic
linking. */
if (phnum > 0) {
fill_unloadable_phdr(phdr, phnum, interp, dynamic);
if (dynamic) {
dyninf.dynamic = dynamic;
dyninf.dynstr = dynstr;
fill_dynamic(s1, &dyninf);
/* put in GOT the dynamic section address and relocate PLT */
write32le(s1->got->data, dynamic->sh_addr);
if (file_type == TCC_OUTPUT_EXE
#if defined(TCC_OUTPUT_DLL_WITH_PLT)
|| file_type == TCC_OUTPUT_DLL
#endif
)
relocate_plt(s1);
/* relocate symbols in .dynsym now that final addresses are known */
for_each_elem(s1->dynsym, 1, sym, ElfW(Sym)) {
if (sym->st_shndx == SHN_UNDEF) {
/* relocate to PLT if symbol corresponds to a PLT entry,
but not if it's a weak symbol */
if (ELFW(ST_BIND)(sym->st_info) == STB_WEAK)
sym->st_value = 0;
else if (sym->st_value)
sym->st_value += s1->plt->sh_addr;
} else if (sym->st_shndx < SHN_LORESERVE) {
/* do symbol relocation */
sym->st_value += s1->sections[sym->st_shndx]->sh_addr;
}
}
}
}
/* if building executable or DLL, then relocate each section
except the GOT which is already relocated */
if (file_type != TCC_OUTPUT_OBJ) {
ret = final_sections_reloc(s1);
if (ret)
goto the_end;
}
/* Perform relocation to GOT or PLT entries */
if (file_type == TCC_OUTPUT_EXE && s1->static_link)
fill_got(s1);
/* Create the ELF file with name 'filename' */
ret = tcc_write_elf_file(s1, filename, phnum, phdr, file_offset, sec_order);
the_end:
tcc_free(s1->symtab_to_dynsym);
tcc_free(sec_order);
tcc_free(phdr);
tcc_free(s1->sym_attrs);
s1->sym_attrs = NULL;
return ret;
}
LIBTCCAPI int tcc_output_file(TCCState *s, const char *filename)
{
int ret;
#ifdef TCC_TARGET_PE
if (s->output_type != TCC_OUTPUT_OBJ) {
ret = pe_output_file(s, filename);
} else
#endif
ret = elf_output_file(s, filename);
return ret;
}
static void *load_data(int fd, unsigned long file_offset, unsigned long size)
{
void *data;
data = tcc_malloc(size);
lseek(fd, file_offset, SEEK_SET);
read(fd, data, size);
return data;
}
typedef struct SectionMergeInfo {
Section *s; /* corresponding existing section */
unsigned long offset; /* offset of the new section in the existing section */
uint8_t new_section; /* true if section 's' was added */
uint8_t link_once; /* true if link once section */
} SectionMergeInfo;
ST_FUNC int tcc_object_type(int fd, ElfW(Ehdr) *h)
{
int size = read(fd, h, sizeof *h);
if (size == sizeof *h && 0 == memcmp(h, ELFMAG, 4)) {
if (h->e_type == ET_REL)
return AFF_BINTYPE_REL;
if (h->e_type == ET_DYN)
return AFF_BINTYPE_DYN;
} else if (size >= 8) {
if (0 == memcmp(h, ARMAG, 8))
return AFF_BINTYPE_AR;
#ifdef TCC_TARGET_COFF
if (((struct filehdr*)h)->f_magic == COFF_C67_MAGIC)
return AFF_BINTYPE_C67;
#endif
}
return 0;
}
/* load an object file and merge it with current files */
/* XXX: handle correctly stab (debug) info */
ST_FUNC int tcc_load_object_file(TCCState *s1,
int fd, unsigned long file_offset)
{
ElfW(Ehdr) ehdr;
ElfW(Shdr) *shdr, *sh;
int size, i, j, offset, offseti, nb_syms, sym_index, ret;
unsigned char *strsec, *strtab;
int *old_to_new_syms;
char *sh_name, *name;
SectionMergeInfo *sm_table, *sm;
ElfW(Sym) *sym, *symtab;
ElfW_Rel *rel;
Section *s;
int stab_index;
src/tccelf.c view on Meta::CPAN
snprintf(filename, sizeof filename, "lib%s.a", libname);
} else {
snprintf(filename, sizeof filename, "lib%s.so", libname);
}
} else if (t != LD_TOK_NAME) {
tcc_error_noabort("filename expected");
ret = -1;
goto lib_parse_error;
}
if (!strcmp(filename, "AS_NEEDED")) {
ret = ld_add_file_list(s1, cmd, 1);
if (ret)
goto lib_parse_error;
} else {
/* TODO: Implement AS_NEEDED support. Ignore it for now */
if (!as_needed) {
ret = ld_add_file(s1, filename);
if (ret)
goto lib_parse_error;
if (group) {
/* Add the filename *and* the libname to avoid future conversions */
dynarray_add((void ***) &libs, &nblibs, tcc_strdup(filename));
if (libname[0] != '\0')
dynarray_add((void ***) &libs, &nblibs, tcc_strdup(libname));
}
}
}
t = ld_next(s1, filename, sizeof(filename));
if (t == ',') {
t = ld_next(s1, filename, sizeof(filename));
}
}
if (group && !as_needed) {
while (new_undef_syms()) {
int i;
for (i = 0; i < nblibs; i ++)
ld_add_file(s1, libs[i]);
}
}
lib_parse_error:
dynarray_reset(&libs, &nblibs);
return ret;
}
/* interpret a subset of GNU ldscripts to handle the dummy libc.so
files */
ST_FUNC int tcc_load_ldscript(TCCState *s1)
{
char cmd[64];
char filename[1024];
int t, ret;
ch = handle_eob();
for(;;) {
t = ld_next(s1, cmd, sizeof(cmd));
if (t == LD_TOK_EOF)
return 0;
else if (t != LD_TOK_NAME)
return -1;
if (!strcmp(cmd, "INPUT") ||
!strcmp(cmd, "GROUP")) {
ret = ld_add_file_list(s1, cmd, 0);
if (ret)
return ret;
} else if (!strcmp(cmd, "OUTPUT_FORMAT") ||
!strcmp(cmd, "TARGET")) {
/* ignore some commands */
t = ld_next(s1, cmd, sizeof(cmd));
if (t != '(')
expect("(");
for(;;) {
t = ld_next(s1, filename, sizeof(filename));
if (t == LD_TOK_EOF) {
tcc_error_noabort("unexpected end of file");
return -1;
} else if (t == ')') {
break;
}
}
} else {
return -1;
}
}
return 0;
}
#endif /* !TCC_TARGET_PE */
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