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Parse and emit hidden visibility

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This adds parsing of (GCC compatible) visibility attribute
in order to mark selected global symbols as hidden.  The generated
.o files contain hidden symbols already, the TCC linker doesn't
yet do the right thing.
This commit is contained in:
Michael Matz
2014-04-14 02:53:11 +02:00
parent 112148172b
commit fbda78aefe
3 changed files with 69 additions and 5 deletions
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60
tccgen.c
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@ -300,6 +300,29 @@ static void weaken_symbol(Sym *sym)
}
}
static void apply_visibility(Sym *sym, CType *type)
{
int vis = sym->type.t & VT_VIS_MASK;
int vis2 = type->t & VT_VIS_MASK;
if (vis == (STV_DEFAULT << VT_VIS_SHIFT))
vis = vis2;
else if (vis2 == (STV_DEFAULT << VT_VIS_SHIFT))
;
else
vis = (vis < vis2) ? vis : vis2;
sym->type.t &= ~VT_VIS_MASK;
sym->type.t |= vis;
if (sym->c > 0) {
int esym_type;
ElfW(Sym) *esym;
esym = &((ElfW(Sym) *)symtab_section->data)[sym->c];
vis >>= VT_VIS_SHIFT;
esym->st_other = (esym->st_other & ~ELFW(ST_VISIBILITY)(-1)) | vis;
}
}
/* ------------------------------------------------------------------------- */
ST_FUNC void swap(int *p, int *q)
@ -436,6 +459,13 @@ static Sym *external_sym(int v, CType *type, int r, char *asm_label)
tcc_error("incompatible types for redefinition of '%s'",
get_tok_str(v, NULL));
}
/* Merge some storage attributes. */
if (type->t & VT_WEAK)
weaken_symbol(s);
if (type->t & VT_VIS_MASK)
apply_visibility(s, type);
return s;
}
@ -2662,6 +2692,24 @@ static void parse_attribute(AttributeDef *ad)
next();
skip(')');
break;
case TOK_VISIBILITY1:
case TOK_VISIBILITY2:
skip('(');
if (tok != TOK_STR)
expect("visibility(\"default|hidden|internal|protected\")");
if (!strcmp (tokc.cstr->data, "default"))
ad->a.visibility = STV_DEFAULT;
else if (!strcmp (tokc.cstr->data, "hidden"))
ad->a.visibility = STV_HIDDEN;
else if (!strcmp (tokc.cstr->data, "internal"))
ad->a.visibility = STV_INTERNAL;
else if (!strcmp (tokc.cstr->data, "protected"))
ad->a.visibility = STV_PROTECTED;
else
expect("visibility(\"default|hidden|internal|protected\")");
next();
skip(')');
break;
case TOK_ALIGNED1:
case TOK_ALIGNED2:
if (tok == '(') {
@ -5656,6 +5704,7 @@ static void decl_initializer_alloc(CType *type, AttributeDef *ad, int r,
/* patch symbol weakness */
if (type->t & VT_WEAK)
weaken_symbol(sym);
apply_visibility(sym, type);
#ifdef CONFIG_TCC_BCHECK
/* handles bounds now because the symbol must be defined
before for the relocation */
@ -5801,6 +5850,7 @@ static void gen_function(Sym *sym)
/* patch symbol weakness (this definition overrules any prototype) */
if (sym->type.t & VT_WEAK)
weaken_symbol(sym);
apply_visibility(sym, &sym->type);
if (tcc_state->do_debug) {
put_stabn(N_FUN, 0, 0, ind - func_ind);
}
@ -5934,6 +5984,8 @@ static int decl0(int l, int is_for_loop_init)
if (ad.a.func_export)
type.t |= VT_EXPORT;
#endif
type.t |= ad.a.visibility << VT_VIS_SHIFT;
if (tok == '{') {
if (l == VT_LOCAL)
tcc_error("cannot use local functions");
@ -5973,6 +6025,11 @@ static int decl0(int l, int is_for_loop_init)
if (sym->type.t & VT_STATIC)
type.t = (type.t & ~VT_EXTERN) | VT_STATIC;
/* If the definition has no visibility use the
one from prototype. */
if (! (type.t & VT_VIS_MASK))
type.t |= sym->type.t & VT_VIS_MASK;
if (!is_compatible_types(&sym->type, &type)) {
func_error1:
tcc_error("incompatible types for redefinition of '%s'",
@ -6063,9 +6120,6 @@ static int decl0(int l, int is_for_loop_init)
extern */
sym = external_sym(v, &type, r, asm_label);
if (type.t & VT_WEAK)
weaken_symbol(sym);
if (ad.alias_target) {
Section tsec;
Elf32_Sym *esym;