tinycc/i386-link.c
grischka 72729d8e36 allow libtcc states to be used concurrently
This allows creation of TCCStates and operation with API
calls independently from each other, even from threads.

Frontend (option parsing/libtcc.c) and backend (linker/tccelf.c)
now depend only on the TCCState (s1) argument.

Compilation per se (tccpp.c, tccgen.c) is still using
globals for convenience.  There is only one entry point
to this section which is tcc_compile() which is protected
by a semaphore.

There are some hacks involved to avoid too many changes,
as well as some changes in order to avoid too many hacks ;)

The test libtcc_test_mt.c shows the feature.  Except this
new file the patch adds 87 lines overall.
2019-12-11 02:36:19 +01:00

239 lines
6.6 KiB
C

#ifdef TARGET_DEFS_ONLY
#define EM_TCC_TARGET EM_386
/* relocation type for 32 bit data relocation */
#define R_DATA_32 R_386_32
#define R_DATA_PTR R_386_32
#define R_JMP_SLOT R_386_JMP_SLOT
#define R_GLOB_DAT R_386_GLOB_DAT
#define R_COPY R_386_COPY
#define R_RELATIVE R_386_RELATIVE
#define R_NUM R_386_NUM
#define ELF_START_ADDR 0x08048000
#define ELF_PAGE_SIZE 0x1000
#define PCRELATIVE_DLLPLT 0
#define RELOCATE_DLLPLT 0
#else /* !TARGET_DEFS_ONLY */
#include "tcc.h"
#ifndef ELF_OBJ_ONLY
/* Returns 1 for a code relocation, 0 for a data relocation. For unknown
relocations, returns -1. */
int code_reloc (int reloc_type)
{
switch (reloc_type) {
case R_386_RELATIVE:
case R_386_16:
case R_386_32:
case R_386_GOTPC:
case R_386_GOTOFF:
case R_386_GOT32:
case R_386_GOT32X:
case R_386_GLOB_DAT:
case R_386_COPY:
return 0;
case R_386_PC16:
case R_386_PC32:
case R_386_PLT32:
case R_386_JMP_SLOT:
return 1;
}
return -1;
}
/* Returns an enumerator to describe whether and when the relocation needs a
GOT and/or PLT entry to be created. See tcc.h for a description of the
different values. */
int gotplt_entry_type (int reloc_type)
{
switch (reloc_type) {
case R_386_RELATIVE:
case R_386_16:
case R_386_GLOB_DAT:
case R_386_JMP_SLOT:
case R_386_COPY:
return NO_GOTPLT_ENTRY;
case R_386_32:
/* This relocations shouldn't normally need GOT or PLT
slots if it weren't for simplicity in the code generator.
See our caller for comments. */
return AUTO_GOTPLT_ENTRY;
case R_386_PC16:
case R_386_PC32:
return AUTO_GOTPLT_ENTRY;
case R_386_GOTPC:
case R_386_GOTOFF:
return BUILD_GOT_ONLY;
case R_386_GOT32:
case R_386_GOT32X:
case R_386_PLT32:
return ALWAYS_GOTPLT_ENTRY;
}
return -1;
}
ST_FUNC unsigned create_plt_entry(TCCState *s1, unsigned got_offset, struct sym_attr *attr)
{
Section *plt = s1->plt;
uint8_t *p;
int modrm;
unsigned plt_offset, relofs;
/* on i386 if we build a DLL, we add a %ebx offset */
if (s1->output_type == TCC_OUTPUT_DLL)
modrm = 0xa3;
else
modrm = 0x25;
/* empty PLT: create PLT0 entry that pushes the library identifier
(GOT + PTR_SIZE) and jumps to ld.so resolution routine
(GOT + 2 * PTR_SIZE) */
if (plt->data_offset == 0) {
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);
}
plt_offset = plt->data_offset;
/* 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;
/* Jump to GOT entry where ld.so initially put the address of ip + 4 */
p = section_ptr_add(plt, 16);
p[0] = 0xff; /* jmp *(got + x) */
p[1] = modrm;
write32le(p + 2, got_offset);
p[6] = 0x68; /* push $xxx */
write32le(p + 7, relofs);
p[11] = 0xe9; /* jmp plt_start */
write32le(p + 12, -(plt->data_offset));
return plt_offset;
}
/* relocate the PLT: compute addresses and offsets in the PLT now that final
address for PLT and GOT are known (see fill_program_header) */
ST_FUNC void relocate_plt(TCCState *s1)
{
uint8_t *p, *p_end;
if (!s1->plt)
return;
p = s1->plt->data;
p_end = p + s1->plt->data_offset;
if (p < p_end) {
add32le(p + 2, s1->got->sh_addr);
add32le(p + 8, s1->got->sh_addr);
p += 16;
while (p < p_end) {
add32le(p + 2, s1->got->sh_addr);
p += 16;
}
}
}
#endif
void relocate(TCCState *s1, ElfW_Rel *rel, int type, unsigned char *ptr, addr_t addr, addr_t val)
{
int sym_index, esym_index;
sym_index = ELFW(R_SYM)(rel->r_info);
switch (type) {
case R_386_32:
if (s1->output_type == TCC_OUTPUT_DLL) {
esym_index = get_sym_attr(s1, sym_index, 0)->dyn_index;
qrel->r_offset = rel->r_offset;
if (esym_index) {
qrel->r_info = ELFW(R_INFO)(esym_index, R_386_32);
qrel++;
return;
} else {
qrel->r_info = ELFW(R_INFO)(0, R_386_RELATIVE);
qrel++;
}
}
add32le(ptr, val);
return;
case R_386_PC32:
if (s1->output_type == TCC_OUTPUT_DLL) {
/* DLL relocation */
esym_index = get_sym_attr(s1, sym_index, 0)->dyn_index;
if (esym_index) {
qrel->r_offset = rel->r_offset;
qrel->r_info = ELFW(R_INFO)(esym_index, R_386_PC32);
qrel++;
return;
}
}
add32le(ptr, val - addr);
return;
case R_386_PLT32:
add32le(ptr, val - addr);
return;
case R_386_GLOB_DAT:
case R_386_JMP_SLOT:
write32le(ptr, val);
return;
case R_386_GOTPC:
add32le(ptr, s1->got->sh_addr - addr);
return;
case R_386_GOTOFF:
add32le(ptr, val - s1->got->sh_addr);
return;
case R_386_GOT32:
case R_386_GOT32X:
/* we load the got offset */
add32le(ptr, get_sym_attr(s1, sym_index, 0)->got_offset);
return;
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);
return;
case R_386_PC16:
if (s1->output_format != TCC_OUTPUT_FORMAT_BINARY)
goto output_file;
write16le(ptr, read16le(ptr) + val - addr);
return;
case R_386_RELATIVE:
#ifdef TCC_TARGET_PE
add32le(ptr, val - s1->pe_imagebase);
#endif
/* do nothing */
return;
case R_386_COPY:
/* This relocation must copy initialized data from the library
to the program .bss segment. Currently made like for ARM
(to remove noise of default case). Is this true?
*/
return;
default:
fprintf(stderr,"FIXME: handle reloc type %d at %x [%p] to %x\n",
type, (unsigned)addr, ptr, (unsigned)val);
return;
}
}
#endif /* !TARGET_DEFS_ONLY */