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tccgen_begin/end_file

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This is supposed to make compilation and linking with
multiple source files (tcc f1.c f2.S ...) behave just
the same as linking object files.

tccgen.c:put_extern_sym2():
- use put_elf_sym to enter new symbols unconditionally

tccelf.c:
- save section state before compilation
- disable symbol hashing during compilation
- merge symbols and update relocations after compilation

tccpe.c:
- re-create s1->uw_sym for each compilation (because it
  may change)
This commit is contained in:
grischka 2017-12-12 17:33:37 +01:00
parent 8490c54dbd
commit 1a4d4b76e8
6 changed files with 81 additions and 68 deletions
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7
libtcc.c
View File

@ -486,7 +486,7 @@ static void error1(TCCState *s1, int is_warning, const char *fmt, va_list ap)
for(pf = s1->include_stack; pf < s1->include_stack_ptr; pf++)
strcat_printf(buf, sizeof(buf), "In file included from %s:%d:\n",
(*pf)->filename, (*pf)->line_num);
if (f->line_num > 0) {
if (s1->error_set_jmp_enabled) {
strcat_printf(buf, sizeof(buf), "%s:%d: ",
f->filename, f->line_num - !!(tok_flags & TOK_FLAG_BOL));
} else {
@ -629,6 +629,7 @@ static int tcc_compile(TCCState *s1)
define_start = define_stack;
filetype = s1->filetype;
is_asm = filetype == AFF_TYPE_ASM || filetype == AFF_TYPE_ASMPP;
tccelf_begin_file(s1);
if (setjmp(s1->error_jmp_buf) == 0) {
s1->nb_errors = 0;
@ -655,6 +656,7 @@ static int tcc_compile(TCCState *s1)
free_defines(define_start);
sym_pop(&global_stack, NULL, 0);
sym_pop(&local_stack, NULL, 0);
tccelf_end_file(s1);
return s1->nb_errors != 0 ? -1 : 0;
}
@ -1016,9 +1018,6 @@ ST_FUNC int tcc_add_file_internal(TCCState *s1, const char *filename, int flags)
obj_type = tcc_object_type(fd, &ehdr);
lseek(fd, 0, SEEK_SET);
/* do not display line number if error */
file->line_num = 0;
#ifdef TCC_TARGET_MACHO
if (0 == obj_type && 0 == strcmp(tcc_fileextension(filename), ".dylib"))
obj_type = AFF_BINTYPE_DYN;

4
tcc.h
View File

@ -1397,6 +1397,8 @@ ST_DATA Section *stab_section, *stabstr_section;
ST_FUNC void tccelf_new(TCCState *s);
ST_FUNC void tccelf_delete(TCCState *s);
ST_FUNC void tccelf_stab_new(TCCState *s);
ST_FUNC void tccelf_begin_file(TCCState *s1);
ST_FUNC void tccelf_end_file(TCCState *s1);
ST_FUNC Section *new_section(TCCState *s1, const char *name, int sh_type, int sh_flags);
ST_FUNC void section_realloc(Section *sec, unsigned long new_size);
@ -1425,7 +1427,7 @@ ST_FUNC void put_stabs_r(const char *str, int type, int other, int desc, unsigne
ST_FUNC void put_stabn(int type, int other, int desc, int value);
ST_FUNC void put_stabd(int type, int other, int desc);
ST_FUNC void resolve_regular_syms(void);
ST_FUNC void resolve_common_syms(TCCState *s1);
ST_FUNC void relocate_syms(TCCState *s1, Section *symtab, int do_resolve);
ST_FUNC void relocate_section(TCCState *s1, Section *s);

120
tccelf.c
View File

@ -130,6 +130,59 @@ ST_FUNC void tccelf_delete(TCCState *s1)
tcc_free(s1->sym_attrs);
}
/* save section data state */
ST_FUNC void tccelf_begin_file(TCCState *s1)
{
Section *s; int i;
for (i = 1; i < s1->nb_sections; i++) {
s = s1->sections[i];
s->sh_offset = s->data_offset;
}
/* disable symbol hashing during compilation */
s = s1->symtab, s->reloc = s->hash, s->hash = NULL;
#if defined TCC_TARGET_X86_64 && defined TCC_TARGET_PE
s1->uw_sym = 0;
#endif
}
/* At the end of compilation, convert any UNDEF syms to global, and merge
with previously existing symbols */
ST_FUNC void tccelf_end_file(TCCState *s1)
{
Section *s = s1->symtab;
int first_sym, nb_syms, *tr, i;
first_sym = s->sh_offset / sizeof (ElfSym);
nb_syms = s->data_offset / sizeof (ElfSym) - first_sym;
s->data_offset = s->sh_offset;
s->link->data_offset = s->link->sh_offset;
s->hash = s->reloc, s->reloc = NULL;
tr = tcc_mallocz(nb_syms * sizeof *tr);
for (i = 0; i < nb_syms; ++i) {
ElfSym *sym = (ElfSym*)s->data + first_sym + i;
if (sym->st_shndx == SHN_UNDEF
&& ELFW(ST_BIND)(sym->st_info) == STB_LOCAL)
sym->st_info = ELFW(ST_INFO)(STB_GLOBAL, ELFW(ST_TYPE)(sym->st_info));
tr[i] = set_elf_sym(s, sym->st_value, sym->st_size, sym->st_info,
sym->st_other, sym->st_shndx, s->link->data + sym->st_name);
}
/* now update relocations */
for (i = 1; i < s1->nb_sections; i++) {
Section *sr = s1->sections[i];
if (sr->sh_type == SHT_RELX && sr->link == s) {
ElfW_Rel *rel = (ElfW_Rel*)(sr->data + sr->sh_offset);
ElfW_Rel *rel_end = (ElfW_Rel*)(sr->data + sr->data_offset);
for (; rel < rel_end; ++rel) {
int n = ELFW(R_SYM)(rel->r_info) - first_sym;
//if (n < 0) tcc_error("internal: invalid symbol index in relocation");
rel->r_info = ELFW(R_INFO)(tr[n], ELFW(R_TYPE)(rel->r_info));
}
}
}
tcc_free(tr);
}
ST_FUNC Section *new_section(TCCState *s1, const char *name, int sh_type, int sh_flags)
{
Section *sec;
@ -269,7 +322,7 @@ ST_FUNC int put_elf_str(Section *s, const char *sym)
len = strlen(sym) + 1;
offset = s->data_offset;
ptr = section_ptr_add(s, len);
memcpy(ptr, sym, len);
memmove(ptr, sym, len);
return offset;
}
@ -335,7 +388,7 @@ ST_FUNC int put_elf_sym(Section *s, addr_t value, unsigned long size,
Section *hs;
sym = section_ptr_add(s, sizeof(ElfW(Sym)));
if (name)
if (name && name[0])
name_offset = put_elf_str(s->link, name);
else
name_offset = 0;
@ -356,7 +409,7 @@ ST_FUNC int put_elf_sym(Section *s, addr_t value, unsigned long size,
if (ELFW(ST_BIND)(info) != STB_LOCAL) {
/* add another hashing entry */
nbuckets = base[0];
h = elf_hash((unsigned char *) name) % nbuckets;
h = elf_hash((unsigned char *)s->link->data + name_offset) % nbuckets;
*ptr = base[2 + h];
base[2 + h] = sym_index;
base[1]++;
@ -373,7 +426,7 @@ ST_FUNC int put_elf_sym(Section *s, addr_t value, unsigned long size,
return sym_index;
}
static int find_elf_sym_1(Section *s, const char *name, int onlydef)
ST_FUNC int find_elf_sym(Section *s, const char *name)
{
ElfW(Sym) *sym;
Section *hs;
@ -389,21 +442,13 @@ static int find_elf_sym_1(Section *s, const char *name, int onlydef)
while (sym_index != 0) {
sym = &((ElfW(Sym) *)s->data)[sym_index];
name1 = (char *) s->link->data + sym->st_name;
if (!strcmp(name, name1) && ELFW(ST_BIND)(sym->st_info) != STB_LOCAL
&& (!onlydef || sym->st_shndx != SHN_UNDEF))
if (!strcmp(name, name1))
return sym_index;
sym_index = ((int *)hs->data)[2 + nbuckets + sym_index];
}
return 0;
}
/* find global ELF symbol 'name' and return its index. Return 0 if not
found. */
ST_FUNC int find_elf_sym(Section *s, const char *name)
{
return find_elf_sym_1(s, name, 0);
}
/* return elf symbol value, signal error if 'err' is nonzero */
ST_FUNC addr_t get_elf_sym_addr(TCCState *s, const char *name, int err)
{
@ -447,17 +492,15 @@ ST_FUNC int set_elf_sym(Section *s, addr_t value, unsigned long size,
sym_type = ELFW(ST_TYPE)(info);
sym_vis = ELFW(ST_VISIBILITY)(other);
sym_index = find_elf_sym(s, name);
esym = &((ElfW(Sym) *)s->data)[sym_index];
if (sym_index && esym->st_value == value && esym->st_size == size
&& esym->st_info == info && esym->st_other == other
&& esym->st_shndx == shndx)
return sym_index;
if (sym_bind != STB_LOCAL) {
/* we search global or weak symbols */
sym_index = find_elf_sym(s, name);
if (!sym_index)
goto do_def;
esym = &((ElfW(Sym) *)s->data)[sym_index];
if (esym->st_value == value && esym->st_size == size && esym->st_info == info
&& esym->st_other == other && esym->st_shndx == shndx)
return sym_index;
if (esym->st_shndx != SHN_UNDEF) {
esym_bind = ELFW(ST_BIND)(esym->st_info);
/* propagate the most constraining visibility */
@ -1220,11 +1263,8 @@ static void tcc_add_linker_symbols(TCCState *s1)
}
}
/* Do final regular symbol preparation (for those coming from .c/.o/.s files,
not from shared libs) */
ST_FUNC void resolve_regular_syms(void)
ST_FUNC void resolve_common_syms(TCCState *s1)
{
int rebuild = 0;
ElfW(Sym) *sym;
/* Allocate common symbols in BSS. */
@ -1238,27 +1278,7 @@ ST_FUNC void resolve_regular_syms(void)
}
/* Now assign linker provided symbols their value. */
tcc_add_linker_symbols(tcc_state);
/* And finally resolve still UNDEF symbols (for multi-file mode),
and globalize those that are still UNDEF. */
rebuild_hash(symtab_section, 0);
for_each_elem(symtab_section, 1, sym, ElfW(Sym)) {
if (sym->st_shndx == SHN_UNDEF) {
const char *name = (char *) symtab_section->link->data + sym->st_name;
int symndx = find_elf_sym_1(symtab_section, name, 1);
if (symndx) {
*sym = ((ElfSym *)symtab_section->data)[symndx];
rebuild = 1;
} else if (ELFW(ST_BIND)(sym->st_info) == STB_LOCAL) {
sym->st_info
= ELFW(ST_INFO)(STB_GLOBAL, ELFW(ST_TYPE)(sym->st_info));
rebuild = 1;
}
}
}
if (rebuild)
rebuild_hash(symtab_section, 0);
tcc_add_linker_symbols(s1);
}
static void tcc_output_binary(TCCState *s1, FILE *f,
@ -2051,7 +2071,7 @@ static int elf_output_file(TCCState *s1, const char *filename)
if (file_type != TCC_OUTPUT_OBJ) {
/* if linking, also link in runtime libraries (libc, libgcc, etc.) */
tcc_add_runtime(s1);
resolve_regular_syms();
resolve_common_syms(s1);
if (!s1->static_link) {
if (file_type == TCC_OUTPUT_EXE) {
@ -2092,14 +2112,6 @@ static int elf_output_file(TCCState *s1, const char *filename)
}
}
build_got_entries(s1);
} else {
for_each_elem(symtab_section, 1, sym, ElfW(Sym)) {
if (sym->st_shndx == SHN_UNDEF
&& ELFW(ST_BIND)(sym->st_info) == STB_LOCAL) {
sym->st_info
= ELFW(ST_INFO)(STB_GLOBAL, ELFW(ST_TYPE)(sym->st_info));
}
}
}
/* we add a section for symbols */

2
tccgen.c
View File

@ -418,7 +418,7 @@ ST_FUNC void put_extern_sym2(Sym *sym, Section *section,
if (sym->asm_label)
name = get_tok_str(sym->asm_label, NULL);
info = ELFW(ST_INFO)(sym_bind, sym_type);
sym->c = set_elf_sym(symtab_section, value, size, info, other, sh_num, name);
sym->c = put_elf_sym(symtab_section, value, size, info, other, sh_num, name);
} else {
esym = elfsym(sym);
esym->st_value = value;

14
tccpe.c
View File

@ -1633,7 +1633,7 @@ static int pe_load_res(TCCState *s1, int fd)
{
struct pe_rsrc_header hdr;
Section *rsrc_section;
int i, ret = -1;
int i, ret = -1, sym_index;
BYTE *ptr;
unsigned offs;
@ -1651,8 +1651,8 @@ static int pe_load_res(TCCState *s1, int fd)
if (!read_mem(fd, offs, ptr, hdr.sectionhdr.SizeOfRawData))
goto quit;
offs = hdr.sectionhdr.PointerToRelocations;
for (i = 0; i < hdr.sectionhdr.NumberOfRelocations; ++i)
{
sym_index = put_elf_sym(symtab_section, 0, 0, 0, 0, rsrc_section->sh_num, ".rsrc");
for (i = 0; i < hdr.sectionhdr.NumberOfRelocations; ++i) {
struct pe_rsrc_reloc rel;
if (!read_mem(fd, offs, &rel, sizeof rel))
goto quit;
@ -1660,7 +1660,7 @@ static int pe_load_res(TCCState *s1, int fd)
if (rel.type != RSRC_RELTYPE)
goto quit;
put_elf_reloc(symtab_section, rsrc_section,
rel.offset, R_XXX_RELATIVE, 0);
rel.offset, R_XXX_RELATIVE, sym_index);
offs += sizeof rel;
}
ret = 0;
@ -1779,9 +1779,9 @@ static unsigned pe_add_uwwind_info(TCCState *s1)
if (NULL == s1->uw_pdata) {
s1->uw_pdata = find_section(tcc_state, ".pdata");
s1->uw_pdata->sh_addralign = 4;
s1->uw_sym = put_elf_sym(symtab_section, 0, 0, 0, 0, text_section->sh_num, NULL);
}
if (0 == s1->uw_sym)
s1->uw_sym = put_elf_sym(symtab_section, 0, 0, 0, 0, text_section->sh_num, ".uw_base");
if (0 == s1->uw_offs) {
/* As our functions all have the same stackframe, we use one entry for all */
static const unsigned char uw_info[] = {
@ -1970,7 +1970,7 @@ ST_FUNC int pe_output_file(TCCState *s1, const char *filename)
tcc_add_bcheck(s1);
pe_add_runtime(s1, &pe);
resolve_regular_syms();
resolve_common_syms(s1);
pe_set_options(s1, &pe);
ret = pe_check_symbols(&pe);

2
tccrun.c
View File

@ -188,7 +188,7 @@ static int tcc_relocate_ex(TCCState *s1, void *ptr, addr_t ptr_diff)
pe_output_file(s1, NULL);
#else
tcc_add_runtime(s1);
resolve_regular_syms();
resolve_common_syms(s1);
build_got_entries(s1);
#endif
if (s1->nb_errors)