Hi,
Can anyone explain me the following gcc/c-decl.c code (4.0.2, seems to
be unchanged in 4.2)?
...
#define I_SYMBOL_BINDING(node) \
(((struct lang_identifier *)
IDENTIFIER_NODE_CHECK(node))->symbol_binding)
...
static void
warn_if_shadowing (tree new_decl)
{
struct c_binding *b;
...
/* Is anything being shadowed? Invisible decls do not count. */
for (b = I_SYMBOL_BINDING (DECL_NAME (new_decl)); b; b = b->shadowed)
if (b->decl && b->decl != new_decl && !b->invisible)
...
}
...
}
...
Let's assume that new_decl is a VAR_DECL node. Than,
IDENTIFIER_NODE_CHECK(DECL_NAME(new_decl))
= new_decl->decl->name, which is an IDENTIFIER_NODE. How is it
possible to cast it to (struct lang_identifier *) ??
[The worst thing is that it seems to work fine.]
Just to recap:
----------------------------------------------------------------------
tree.h:
struct tree_identifier GTY(())
{
struct tree_common ommon;
struct ht_identifier id;
};
symtab.h:
struct ht_identifier GTY(())
{
const unsigned char *str;
unsigned int len;
unsigned int hash_value;
};
c-decl.c:
struct c_binding GTY((chain_next ("%h.prev")))
{
tree decl; /* the decl bound */
tree type; /* the type in this scope */
tree id; /* the identifier it's bound to */
struct c_binding *prev; /* the previous decl in this scope */
struct c_binding *shadowed; /* the innermost decl shadowed by this one */
unsigned int depth : 28; /* depth of this scope */
BOOL_BITFIELD invisible : 1; /* normal lookup should ignore this
binding */
BOOL_BITFIELD nested : 1; /* do not set DECL_CONTEXT when popping */
BOOL_BITFIELD inner_comp : 1; /* incomplete array completed in inner
scope */
/* one free bit */
};
c-decl.c:
struct lang_identifier GTY(())
{
struct c_common_identifier common_id;
struct c_binding *symbol_binding; /* vars, funcs, constants, typedefs */
struct c_binding *tag_binding; /* struct/union/enum tags */
struct c_binding *label_binding; /* labels */
};
----------------------------------------------------------------------
Thx! Regards,
Domagoj
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