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tinycc
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Support aliasing static global nonfunction objects 

Enables code such as:

    #undef NDEBUG
    #include <assert.h>
    #include <stdint.h>
    static int st_x = 42;
    static int st_x_ __attribute((alias("st_x")));
    int main(void){ assert((uintptr_t)&st_x == (uintptr_t)&st_x_); }

which would previously fail with no compiler warnings. The limitation of
this is that the alias must be done (or redone) after an actual definition.
An alias done right after a later overridden tentative declaration won't
work (sufficient for my use case).
This commit is contained in:
Petr Skocik 2023-10-08 18:55:04 +02:00
parent b214fb6ed3
commit 08c777053c
1 changed files with 10 additions and 0 deletions
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10
tccgen.c
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@ -8661,6 +8661,16 @@ static int decl(int l)
else if (l == VT_CONST)
/* uninitialized global variables may be overridden */
type.t |= VT_EXTERN;
if (ad.alias_target && 1) {
Sym *alias_target = sym_find(ad.alias_target);
ElfSym *esym = elfsym(alias_target);
if (!esym) tcc_error("unsupported forward __alias__ attribute");
sym = external_sym(v, &type, r, &ad);
put_extern_sym2(sym, esym->st_shndx,
esym->st_value, esym->st_size, 1);
}
decl_initializer_alloc(&type, &ad, r, has_init, v, l == VT_CONST);
}
}