Fix some multi-file corner cases with asm

for this we have to create also asm symbols as VT_STATIC initially except if there's an indication that it should be global (.globl or undefined at end of unit). For this to work we need to be able to globalize symbols after they were local and enter them into the ELF hash tables, and also adjust the symbols that were potentially already used in relocs when they were still local. The easiest is to do a proper symbol resolution step also in multi-file mode, for regular symbols (the non-dynamic ones, i.e. not from shared libs).

Michael Matz committed 8 years ago

Commit 8490c541 parent 3ae1a2a5 files · +73 −44Browse files

Unified · Split

5 files

tcc.h +1 −3
tccasm.c +6 −15
tccelf.c +64 −22
tccpe.c +1 −2
tccrun.c +1 −2

tcc.h+1−3

@@ -911,7 +911,6 @@ struct filespec { · 910 unmodified lines
911	911
912	912	/* symbol was created by tccasm.c first */
913	913	#define VT_ASM (VT_VOID \| VT_UNSIGNED)
914		−#define VT_ASM_GLOBAL VT_DEFSIGN
915	914	#define IS_ASM_SYM(sym) (((sym)->type.t & (VT_BTYPE \| VT_ASM)) == VT_ASM)
916	915
917	916	/* token values */
@@ -1426,11 +1425,10 @@ ST_FUNC void put_stabs_r(const char *str, int type, int other, int desc, unsigne · 508 unmodified lines
1426	1425	ST_FUNC void put_stabn(int type, int other, int desc, int value);
1427	1426	ST_FUNC void put_stabd(int type, int other, int desc);
1428	1427
1429		−ST_FUNC void relocate_common_syms(void);
	1428	+ST_FUNC void resolve_regular_syms(void);
1430	1429	ST_FUNC void relocate_syms(TCCState s1, Section symtab, int do_resolve);
1431	1430	ST_FUNC void relocate_section(TCCState s1, Section s);
1432	1431
1433		−ST_FUNC void tcc_add_linker_symbols(TCCState *s1);
1434	1432	ST_FUNC int tcc_object_type(int fd, ElfW(Ehdr) *h);
1435	1433	ST_FUNC int tcc_load_object_file(TCCState *s1, int fd, unsigned long file_offset);
1436	1434	ST_FUNC int tcc_load_archive(TCCState *s1, int fd);

tccasm.c+6−15

@@ -42,13 +42,12 @@ static Sym *asm_label_find(int v) · 41 unmodified lines
42	42	return sym;
43	43	}
44	44
45		−static Sym *asm_label_push(int v, int t)
	45	+static Sym *asm_label_push(int v)
46	46	{
47		− Sym *sym = global_identifier_push(v, t, 0);
48	47	/* We always add VT_EXTERN, for sym definition that's tentative
49	48	(for .set, removed for real defs), for mere references it's correct
50	49	as is. */
51		− sym->type.t \|= VT_ASM \| VT_EXTERN;
	50	+ Sym *sym = global_identifier_push(v, VT_ASM \| VT_EXTERN \| VT_STATIC, 0);
52	51	sym->r = VT_CONST \| VT_SYM;
53	52	return sym;
54	53	}
@@ -67,7 +66,7 @@ ST_FUNC Sym* get_asm_sym(int name, Sym *csym) · 12 unmodified lines
67	66	{
68	67	Sym *sym = asm_label_find(name);
69	68	if (!sym) {
70		− sym = asm_label_push(name, 0);
	69	+ sym = asm_label_push(name);
71	70	if (csym)
72	71	sym->c = csym->c;
73	72	}
@@ -102,7 +101,7 @@ static void asm_expr_unary(TCCState s1, ExprValue pe) · 28 unmodified lines
102	101	/* forward */
103	102	if (!sym \|\| (sym->c && elfsym(sym)->st_shndx != SHN_UNDEF)) {
104	103	/* if the last label is defined, then define a new one */
105		− sym = asm_label_push(label, VT_STATIC);
	104	+ sym = asm_label_push(label);
106	105	}
107	106	}
108	107	pe->v = 0;
@@ -381,7 +380,7 @@ static Sym* asm_new_label1(TCCState *s1, int label, int is_local, · 272 unmodified lines
381	380	}
382	381	} else {
383	382	new_label:
384		− sym = asm_label_push(label, is_local == 1 ? VT_STATIC : 0);
	383	+ sym = asm_label_push(label);
385	384	}
386	385	if (!sym->c)
387	386	put_extern_sym2(sym, NULL, 0, 0, 0);
@@ -392,11 +391,6 @@ static Sym* asm_new_label1(TCCState *s1, int label, int is_local, · 4 unmodified lines
392	391	if (is_local != 2)
393	392	sym->type.t &= ~VT_EXTERN;
394	393
395		− if (IS_ASM_SYM(sym) && !(sym->type.t & VT_ASM_GLOBAL)) {
396		− sym->type.t \|= VT_STATIC;
397		− update_storage(sym);
398		− }
399		−
400	394	return sym;
401	395	}
402	396
@@ -679,11 +673,8 @@ static void asm_parse_directive(TCCState *s1, int global) · 276 unmodified lines
679	673	Sym *sym;
680	674	next();
681	675	sym = get_asm_sym(tok, NULL);
682		− if (tok1 != TOK_ASMDIR_hidden) {
	676	+ if (tok1 != TOK_ASMDIR_hidden)
683	677	sym->type.t &= ~VT_STATIC;
684		− if (IS_ASM_SYM(sym))
685		− sym->type.t \|= VT_ASM_GLOBAL;
686		− }
687	678	if (tok1 == TOK_ASMDIR_weak)
688	679	sym->a.weak = 1;
689	680	else if (tok1 == TOK_ASMDIR_hidden)

tccelf.c+64−22

@@ -299,6 +299,9 @@ static void rebuild_hash(Section *s, unsigned int nb_buckets) · 298 unmodified lines
299	299	strtab = s->link->data;
300	300	nb_syms = s->data_offset / sizeof(ElfW(Sym));
301	301
	302	+ if (!nb_buckets)
	303	+ nb_buckets = ((int*)s->hash->data)[0];
	304	+
302	305	s->hash->data_offset = 0;
303	306	ptr = section_ptr_add(s->hash, (2 + nb_buckets + nb_syms) * sizeof(int));
304	307	ptr[0] = nb_buckets;
@@ -370,9 +373,7 @@ ST_FUNC int put_elf_sym(Section *s, addr_t value, unsigned long size, · 65 unmodified lines
370	373	return sym_index;
371	374	}
372	375
373		−/* find global ELF symbol 'name' and return its index. Return 0 if not
374		− found. */
375		−ST_FUNC int find_elf_sym(Section s, const char name)
	376	+static int find_elf_sym_1(Section s, const char name, int onlydef)
376	377	{
377	378	ElfW(Sym) *sym;
378	379	Section *hs;
@@ -388,13 +389,21 @@ ST_FUNC int find_elf_sym(Section s, const char name) · 9 unmodified lines
388	389	while (sym_index != 0) {
389	390	sym = &((ElfW(Sym) *)s->data)[sym_index];
390	391	name1 = (char *) s->link->data + sym->st_name;
391		− if (!strcmp(name, name1) && ELFW(ST_BIND)(sym->st_info) != STB_LOCAL)
	392	+ if (!strcmp(name, name1) && ELFW(ST_BIND)(sym->st_info) != STB_LOCAL
	393	+ && (!onlydef \|\| sym->st_shndx != SHN_UNDEF))
392	394	return sym_index;
393	395	sym_index = ((int *)hs->data)[2 + nbuckets + sym_index];
394	396	}
395	397	return 0;
396	398	}
397	399
	400	+/* find global ELF symbol 'name' and return its index. Return 0 if not
	401	+ found. */
	402	+ST_FUNC int find_elf_sym(Section s, const char name)
	403	+{
	404	+ return find_elf_sym_1(s, name, 0);
	405	+}
	406	+
398	407	/* return elf symbol value, signal error if 'err' is nonzero */
399	408	ST_FUNC addr_t get_elf_sym_addr(TCCState s, const char name, int err)
400	409	{
@@ -716,21 +725,6 @@ static void sort_syms(TCCState s1, Section s) · 315 unmodified lines
716	725	tcc_free(old_to_new_syms);
717	726	}
718	727
719		−/* relocate common symbols in the .bss section */
720		−ST_FUNC void relocate_common_syms(void)
721		−{
722		− ElfW(Sym) *sym;
723		−
724		− for_each_elem(symtab_section, 1, sym, ElfW(Sym)) {
725		− if (sym->st_shndx == SHN_COMMON) {
726		− /* symbol alignment is in st_value for SHN_COMMONs */
727		− sym->st_value = section_add(bss_section, sym->st_size,
728		− sym->st_value);
729		− sym->st_shndx = bss_section->sh_num;
730		− }
731		− }
732		−}
733		−
734	728	/* relocate symbol table, resolve undefined symbols if do_resolve is
735	729	true and output error if undefined symbol. */
736	730	ST_FUNC void relocate_syms(TCCState s1, Section symtab, int do_resolve)
@@ -1167,7 +1161,7 @@ ST_FUNC void tcc_add_runtime(TCCState *s1) · 430 unmodified lines
1167	1161	/* add various standard linker symbols (must be done after the
1168	1162	sections are filled (for example after allocating common
1169	1163	symbols)) */
1170		−ST_FUNC void tcc_add_linker_symbols(TCCState *s1)
	1164	+static void tcc_add_linker_symbols(TCCState *s1)
1171	1165	{
1172	1166	char buf[1024];
1173	1167	int i;
@@ -1226,6 +1220,47 @@ ST_FUNC void tcc_add_linker_symbols(TCCState *s1) · 52 unmodified lines
1226	1220	}
1227	1221	}
1228	1222
	1223	+/* Do final regular symbol preparation (for those coming from .c/.o/.s files,
	1224	+ not from shared libs) */
	1225	+ST_FUNC void resolve_regular_syms(void)
	1226	+{
	1227	+ int rebuild = 0;
	1228	+ ElfW(Sym) *sym;
	1229	+
	1230	+ /* Allocate common symbols in BSS. */
	1231	+ for_each_elem(symtab_section, 1, sym, ElfW(Sym)) {
	1232	+ if (sym->st_shndx == SHN_COMMON) {
	1233	+ /* symbol alignment is in st_value for SHN_COMMONs */
	1234	+ sym->st_value = section_add(bss_section, sym->st_size,
	1235	+ sym->st_value);
	1236	+ sym->st_shndx = bss_section->sh_num;
	1237	+ }
	1238	+ }
	1239	+
	1240	+ /* Now assign linker provided symbols their value. */
	1241	+ tcc_add_linker_symbols(tcc_state);
	1242	+
	1243	+ /* And finally resolve still UNDEF symbols (for multi-file mode),
	1244	+ and globalize those that are still UNDEF. */
	1245	+ rebuild_hash(symtab_section, 0);
	1246	+ for_each_elem(symtab_section, 1, sym, ElfW(Sym)) {
	1247	+ if (sym->st_shndx == SHN_UNDEF) {
	1248	+ const char name = (char ) symtab_section->link->data + sym->st_name;
	1249	+ int symndx = find_elf_sym_1(symtab_section, name, 1);
	1250	+ if (symndx) {
	1251	+ sym = ((ElfSym )symtab_section->data)[symndx];
	1252	+ rebuild = 1;
	1253	+ } else if (ELFW(ST_BIND)(sym->st_info) == STB_LOCAL) {
	1254	+ sym->st_info
	1255	+ = ELFW(ST_INFO)(STB_GLOBAL, ELFW(ST_TYPE)(sym->st_info));
	1256	+ rebuild = 1;
	1257	+ }
	1258	+ }
	1259	+ }
	1260	+ if (rebuild)
	1261	+ rebuild_hash(symtab_section, 0);
	1262	+}
	1263	+
1229	1264	static void tcc_output_binary(TCCState s1, FILE f,
1230	1265	const int *sec_order)
1231	1266	{
@@ -2016,8 +2051,7 @@ static int elf_output_file(TCCState s1, const char filename) · 784 unmodified lines
2016	2051	if (file_type != TCC_OUTPUT_OBJ) {
2017	2052	/* if linking, also link in runtime libraries (libc, libgcc, etc.) */
2018	2053	tcc_add_runtime(s1);
2019		− relocate_common_syms();
2020		− tcc_add_linker_symbols(s1);
	2054	+ resolve_regular_syms();
2021	2055
2022	2056	if (!s1->static_link) {
2023	2057	if (file_type == TCC_OUTPUT_EXE) {
@@ -2058,6 +2092,14 @@ static int elf_output_file(TCCState s1, const char filename) · 34 unmodified lines
2058	2092	}
2059	2093	}
2060	2094	build_got_entries(s1);
	2095	+ } else {
	2096	+ for_each_elem(symtab_section, 1, sym, ElfW(Sym)) {
	2097	+ if (sym->st_shndx == SHN_UNDEF
	2098	+ && ELFW(ST_BIND)(sym->st_info) == STB_LOCAL) {
	2099	+ sym->st_info
	2100	+ = ELFW(ST_INFO)(STB_GLOBAL, ELFW(ST_TYPE)(sym->st_info));
	2101	+ }
	2102	+ }
2061	2103	}
2062	2104
2063	2105	/* we add a section for symbols */

tccpe.c+1−2

@@ -1970,8 +1970,7 @@ ST_FUNC int pe_output_file(TCCState s1, const char filename) · 1969 unmodified lines
1970	1970
1971	1971	tcc_add_bcheck(s1);
1972	1972	pe_add_runtime(s1, &pe);
1973		− relocate_common_syms(); /* assign bss addresses */
1974		− tcc_add_linker_symbols(s1);
	1973	+ resolve_regular_syms();
1975	1974	pe_set_options(s1, &pe);
1976	1975
1977	1976	ret = pe_check_symbols(&pe);

tccrun.c+1−2

@@ -188,8 +188,7 @@ static int tcc_relocate_ex(TCCState s1, void ptr, addr_t ptr_diff) · 187 unmodified lines
188	188	pe_output_file(s1, NULL);
189	189	#else
190	190	tcc_add_runtime(s1);
191		− relocate_common_syms();
192		− tcc_add_linker_symbols(s1);
	191	+ resolve_regular_syms();
193	192	build_got_entries(s1);
194	193	#endif
195	194	if (s1->nb_errors)

Fix some multi-file corner cases with asm

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