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tcc-stupidos/i386-link.c
herman ten brugge 2f2708a769 Add dwarf support 
The new gcc12 release does not support stabs any more.
This was a good reason to add support for dwarf.

The stabs code still works and is used if configure option --dwarf
is not used.

Tested on x86_64, i386, arm, arm64, riscv64 with dwarf-5.
Some debuggers may not support dwarf-5. Try using older dwarf versions
i that case.
The tccmacho.c code probably need some support for dwarf.

arm-gen.c, arm64-gen.c, i386-gen.c, riscv64-gen.c, x86_64-gen.
- fix get_sym_ref symbol size

arm-link.c, arm64-link.c, i386-link.c, riscv64-link.c, x86_64-link.c
- add R_DATA_32U

libtcc.c:
- parse -gdwarf option

tcc.c:
- add dwarf option

tcc.h:
- add dwarf option and sections

tccelf.c:
- init dwarf sections
- avoid adding sh_addr for dwarf sections
- remove dwarf relocs for output dll
- add dwarf sections for tccrun

tccgen.c:
- add dwarf defines + global data
- add dwarf_* functions
- mix dwarf code with stabs code
- a trick is used to emit function name in .debug_line section so
  only this section has to be parsed instead of .debug_info and
  .debug_abbrev.
- fix init debug_modes

tccrun.c:
- add dwarf sections in rt_context
- init them in tcc_run
- add new dwarf code rt_printline_dwarf to find file/function

dwarf.h:
- New file

tcc-doc.texi:
- document dwarf

configure:
- add dwarf option

lib/Makefile
- change -gstabs into -gdwarf

lib/bt-exe.c, tests/tests2/Makefile, tests/tests2/126_bound_global:
- Add __bound_init call
- Add new testcase to test it
2022-05-05 09:10:37 +02:00

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#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_32U 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 1
#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:
case R_386_TLS_GD:
case R_386_TLS_LDM:
case R_386_TLS_LDO_32:
case R_386_TLS_LE:
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:
case R_386_TLS_GD:
case R_386_TLS_LDM:
case R_386_TLS_LDO_32:
case R_386_TLS_LE:
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->plt->reloc ? s1->plt->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 - sizeof (ElfW_Rel));
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 (s1->output_type != TCC_OUTPUT_DLL && 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;
}
}
if (s1->plt->reloc) {
ElfW_Rel *rel;
int x = s1->plt->sh_addr + 16 + 6;
p = s1->got->data;
for_each_elem(s1->plt->reloc, 0, rel, ElfW_Rel) {
write32le(p + rel->r_offset, x);
x += 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;
case R_386_TLS_GD:
{
static const unsigned char expect[] = {
/* lea 0(,%ebx,1),%eax */
0x8d, 0x04, 0x1d, 0x00, 0x00, 0x00, 0x00,
/* call __tls_get_addr@PLT */
0xe8, 0xfc, 0xff, 0xff, 0xff };
static const unsigned char replace[] = {
/* mov %gs:0,%eax */
0x65, 0xa1, 0x00, 0x00, 0x00, 0x00,
/* sub 0,%eax */
0x81, 0xe8, 0x00, 0x00, 0x00, 0x00 };
if (memcmp (ptr-3, expect, sizeof(expect)) == 0) {
ElfW(Sym) *sym;
Section *sec;
int32_t x;
memcpy(ptr-3, replace, sizeof(replace));
rel[1].r_info = ELFW(R_INFO)(0, R_386_NONE);
sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
sec = s1->sections[sym->st_shndx];
x = sym->st_value - sec->sh_addr - sec->data_offset;
add32le(ptr + 5, -x);
}
else
tcc_error("unexpected R_386_TLS_GD pattern");
}
return;
case R_386_TLS_LDM:
{
static const unsigned char expect[] = {
/* lea 0(%ebx),%eax */
0x8d, 0x83, 0x00, 0x00, 0x00, 0x00,
/* call __tls_get_addr@PLT */
0xe8, 0xfc, 0xff, 0xff, 0xff };
static const unsigned char replace[] = {
/* mov %gs:0,%eax */
0x65, 0xa1, 0x00, 0x00, 0x00, 0x00,
/* nop */
0x90,
/* lea 0(%esi,%eiz,1),%esi */
0x8d, 0x74, 0x26, 0x00 };
if (memcmp (ptr-2, expect, sizeof(expect)) == 0) {
memcpy(ptr-2, replace, sizeof(replace));
rel[1].r_info = ELFW(R_INFO)(0, R_386_NONE);
}
else
tcc_error("unexpected R_386_TLS_LDM pattern");
}
return;
case R_386_TLS_LDO_32:
case R_386_TLS_LE:
{
ElfW(Sym) *sym;
Section *sec;
int32_t x;
sym = &((ElfW(Sym) *)symtab_section->data)[sym_index];
sec = s1->sections[sym->st_shndx];
x = val - sec->sh_addr - sec->data_offset;
add32le(ptr, x);
}
return;
case R_386_NONE:
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 */
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