tinycc/c67-link.c
Thomas Preud'homme 0bf262864c Fix PLT creation for i386
i386 target does not have PC relative loads. Its ABI therefore require
ebx register to points to the GOT when executing a PLT entry. This means
that PLT entry cannot be used transparently, the compiler needs to
expect execution of a PLT entry to be able to use one, that is a PLT
entry should only be created if the relocation explicitely asks for it
(eg. R_386_PLT32).

This patch creates a new target macro PCRELATIVE_DLLPLT to indicate
whether a target can do a PC relative load in PLT entry when building a
dynamic library. Executable do not normally pose a problem because they
are loaded at a fixed address and thus the absolute address of GOT can
be used.

Note that in such a case, if the compiler does not use a PLT aware
relocation for external access then the code relocation will fall on the
dynamic loader since there is no PLT entry to relocate too.
2016-12-10 09:44:09 +00:00

60 lines
1.7 KiB
C

#ifdef TARGET_DEFS_ONLY
#define EM_TCC_TARGET EM_C60
/* relocation type for 32 bit data relocation */
#define R_DATA_32 R_C60_32
#define R_DATA_PTR R_C60_32
#define R_JMP_SLOT R_C60_JMP_SLOT
#define R_GLOB_DAT R_C60_GLOB_DAT
#define R_COPY R_C60_COPY
#define R_NUM R_C60_NUM
#define ELF_START_ADDR 0x00000400
#define ELF_PAGE_SIZE 0x1000
#define HAVE_SECTION_RELOC
#define PCRELATIVE_DLLPLT 0
#else /* !TARGET_DEFS_ONLY */
#include "tcc.h"
ST_DATA struct reloc_info relocs_info[R_NUM];
void relocate_init(Section *sr) {}
void relocate(TCCState *s1, ElfW_Rel *rel, int type, char *ptr, addr_t addr, addr_t val)
{
switch(type) {
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;
}
}
#endif /* !TARGET_DEFS_ONLY */