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arm: Use proper PLT/GOT for -run.

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Same as with x86_64, disable the runtime_plt_and_got hack
for -run on arm as well.  For that we need to handle several
relocations as (potentially) generating PLT slots as well.
Tested with mpfr-3.1.2 and gawk (both using --disable-shared),
there are two resp. five pre-existing problems, so no regressions.

This also works toward enabling real shared libs for arm,
but it's not there yet.
This commit is contained in:
Michael Matz 2014-04-06 01:02:42 +02:00
parent 9750d0b725
commit 01c0419234
2 changed files with 54 additions and 10 deletions
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2
tcc.h
View File

@ -712,7 +712,7 @@ struct TCCState {
void *write_mem;
unsigned long mem_size;
# endif
# if !defined TCC_TARGET_PE && (defined TCC_TARGET_ARM)
# if !defined TCC_TARGET_PE && (0)
/* write PLT and GOT here */
char *runtime_plt_and_got;
unsigned runtime_plt_and_got_offset;

62
tccelf.c
View File

@ -20,6 +20,9 @@
#include "tcc.h"
/* Define this to get some debug output during relocation processing. */
#undef DEBUG_RELOC
/* XXX: avoid static variable */
static int new_undef_sym = 0; /* Is there a new undefined sym since last new_undef_sym() */
@ -438,6 +441,9 @@ ST_FUNC void relocate_syms(TCCState *s1, int do_resolve)
addr = resolve_sym(s1, name);
if (addr) {
sym->st_value = (addr_t)addr;
#ifdef DEBUG_RELOC
printf ("relocate_sym: %s -> 0x%x\n", name, sym->st_value);
#endif
goto found;
}
#endif
@ -601,6 +607,11 @@ ST_FUNC void relocate_section(TCCState *s1, Section *s)
{
int x, is_thumb, is_call, h, blx_avail, is_bl, th_ko;
x = (*(int *) ptr) & 0xffffff;
if (sym->st_shndx == SHN_UNDEF)
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;
@ -610,6 +621,10 @@ ST_FUNC void relocate_section(TCCState *s1, Section *s)
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);
#ifdef TCC_HAS_RUNTIME_PLTGOT
@ -622,7 +637,7 @@ ST_FUNC void relocate_section(TCCState *s1, Section *s)
}
#endif
if (th_ko || x >= 0x2000000 || x < -0x2000000)
tcc_error("can't relocate value at %x",addr);
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 */
@ -686,7 +701,7 @@ ST_FUNC void relocate_section(TCCState *s1, Section *s)
- 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 && !to_plt))
tcc_error("can't relocate value at %x",addr);
tcc_error("can't relocate value at %x,%d",addr, type);
/* Compute and store final offset */
s = (x >> 24) & 1;
@ -743,7 +758,7 @@ ST_FUNC void relocate_section(TCCState *s1, Section *s)
x = (x * 2) / 2;
x += val - addr;
if((x^(x>>1))&0x40000000)
tcc_error("can't relocate value at %x",addr);
tcc_error("can't relocate value at %x,%d",addr, type);
(*(int *)ptr) |= x & 0x7fffffff;
}
case R_ARM_ABS32:
@ -769,6 +784,10 @@ ST_FUNC void relocate_section(TCCState *s1, Section *s)
if ((0x0ffffff0 & *(int*)ptr) == 0x012FFF10)
*(int*)ptr ^= 0xE12FFF10 ^ 0xE1A0F000; /* BX Rm -> MOV PC, Rm */
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). */
@ -1166,7 +1185,7 @@ static unsigned long put_got_entry(TCCState *s1,
/* the symbol is modified so that it will be relocated to
the PLT */
if (s1->output_type == TCC_OUTPUT_EXE)
if (sym->st_shndx == SHN_UNDEF)
offset = plt->data_offset - 16;
}
#elif defined(TCC_TARGET_C67)
@ -1240,22 +1259,47 @@ ST_FUNC void build_got_entries(TCCState *s1)
}
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);
if (type == R_ARM_GOT32 || type == R_ARM_PLT32) {
sym_index = ELFW(R_SYM)(rel->r_info);
sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
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) {
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;
put_got_entry(s1, reloc_type, sym->st_size, sym->st_info,
sym_index);
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: