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Support R_ARM_THM_JUMP24 relocation to plt

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Add thumb stubs switching from thumb mode to arm mode to *all* PLT
entries so that R_ARM_THM_JUMP24 relocations to PLT entries can be
satisfied.
This commit is contained in:
Thomas Preud'homme 2012-10-28 19:38:38 +01:00
parent b0f08ace94
commit e07802e39d
1 changed files with 18 additions and 8 deletions
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26
tccelf.c
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@ -638,7 +638,8 @@ ST_FUNC void relocate_section(TCCState *s1, Section *s)
case R_ARM_THM_JUMP24:
{
int x, hi, lo, s, j1, j2, i1, i2, imm10, imm11;
int to_thumb, is_call, blx_bit = 1 << 12;
int to_thumb, is_call, to_plt, blx_bit = 1 << 12;
Section *plt;
/* weak reference */
if (sym->st_shndx == SHN_UNDEF &&
@ -662,9 +663,14 @@ ST_FUNC void relocate_section(TCCState *s1, Section *s)
/* Relocation infos */
to_thumb = val & 1;
plt = s1->plt;
to_plt = (val >= plt->sh_addr) &&
(val < plt->sh_addr + plt->data_offset);
is_call = (type == R_ARM_THM_CALL);
/* Compute final offset */
if (to_plt && !is_call) /* Point to 1st instr of Thumb stub */
x -= 4;
x += val - addr;
if (!to_thumb && is_call) {
blx_bit = 0; /* bl -> blx */
@ -675,9 +681,9 @@ ST_FUNC void relocate_section(TCCState *s1, Section *s)
* offset must not be out of range
* if target is to be entered in arm mode:
- bit 1 must not set
- instruction must be a call (bl) */
- instruction must be a call (bl) or a jump to PLT */
if (!to_thumb || x >= 0x1000000 || x < -0x1000000)
if (to_thumb || (val & 2) || !is_call)
if (to_thumb || (val & 2) || (!is_call && !to_plt))
tcc_error("can't relocate value at %x",addr);
/* Compute and store final offset */
@ -1096,10 +1102,13 @@ static void put_got_entry(TCCState *s1,
put32(p + 12, 0xe5bef008);
}
p = section_ptr_add(plt, 16);
put32(p , 0xe59fc004);
put32(p+4, 0xe08fc00c);
put32(p+8, 0xe59cf000);
p = section_ptr_add(plt, 20);
put32(p , 0x4778); // bx pc
put32(p+2, 0x46c0); // nop
p += 4;
put32(p , 0xe59fc004); // ldr ip, [pc, #4] // offset in GOT
put32(p+4, 0xe08fc00c); // add ip, pc, ip // absolute address or offset
put32(p+8, 0xe59cf000); // ldr pc, [ip] // load absolute address or load offset
put32(p+12, s1->got->data_offset);
/* the symbol is modified so that it will be relocated to
@ -2057,8 +2066,9 @@ static int elf_output_file(TCCState *s1, const char *filename)
#elif defined(TCC_TARGET_ARM)
int x;
x=s1->got->sh_addr - s1->plt->sh_addr - 12;
p +=16;
p += 16;
while (p < p_end) {
p += 4;
put32(p + 12, x + get32(p + 12) + s1->plt->data - p);
p += 16;
}