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Add support for R_ARM_THM_{JUMP24,CALL} relocs

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Add support for relocations R_ARM_THM_JUMP24 and R_ARM_THM_CALL. These
are encountered with gcc when compiling for armv6 or greater with
-mthumb flag and a call (conditional or not) is done.
This commit is contained in:
Thomas Preud'homme 2012-10-07 17:48:46 +02:00
parent 508df168f4
commit fad68c9163
2 changed files with 66 additions and 1 deletions
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3
elf.h
View File

@ -1673,7 +1673,7 @@ typedef Elf32_Addr Elf32_Conflict;
#define R_ARM_THM_ABS5 7
#define R_ARM_ABS8 8 /* Direct 8 bit */
#define R_ARM_SBREL32 9
#define R_ARM_THM_PC22 10
#define R_ARM_THM_CALL 10
#define R_ARM_THM_PC8 11
#define R_ARM_AMP_VCALL9 12
#define R_ARM_SWI24 13
@ -1690,6 +1690,7 @@ typedef Elf32_Addr Elf32_Conflict;
#define R_ARM_PLT32 27 /* 32 bit PLT address */
#define R_ARM_CALL 28
#define R_ARM_JUMP24 29
#define R_ARM_THM_JUMP24 30
#define R_ARM_V4BX 40
#define R_ARM_PREL31 42
#define R_ARM_MOVW_ABS_NC 43

64
tccelf.c
View File

@ -631,6 +631,70 @@ ST_FUNC void relocate_section(TCCState *s1, Section *s)
(*(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_CALL:
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;
/* 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;
/* Relocation infos */
to_thumb = val & 1;
is_call = (type == R_ARM_THM_CALL);
/* Compute final offset */
x += val - addr;
if (!to_thumb && is_call) {
blx_bit = 0; /* bl -> blx */
x = (x + 3) & -4; /* Compute offset from aligned PC */
}
/* Check that relocation is possible
* 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) */
if (!to_thumb || x >= 0x1000000 || x < -0x1000000)
if (to_thumb || (val & 2) || !is_call)
tcc_error("can't relocate value at %x",addr);
/* Compute and store final offset */
s = (x >> 24) & 1;
i1 = (x >> 23) & 1;
i2 = (x >> 22) & 1;
j1 = s ^ (i1 ^ 1);
j2 = s ^ (i2 ^ 1);
imm10 = (x >> 12) & 0x3ff;
imm11 = (x >> 1) & 0x7ff;
(*(uint16_t *)ptr) = (uint16_t) ((hi & 0xf800) |
(s << 10) | imm10);
(*(uint16_t *)(ptr+2)) = (uint16_t) ((lo & 0xc000) |
(j1 << 13) | blx_bit | (j2 << 11) |
imm11);
}
break;
case R_ARM_MOVT_ABS:
case R_ARM_MOVW_ABS_NC:
{