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cp-tree.h (default_hash_traits <lang_identifier *>): New specialization.

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* cp-tree.h (default_hash_traits <lang_identifier *>): New
	specialization.
	* name-lookup.c (lookup_extern_c_fun_in_all_ns): Delete.
	(extern_c_fns): New hash table.
	(check_extern_c_conflict): New, broken out of ...
	(pushdecl_maybe_friend_1): ... here.  Call it.
	(c_linkage_bindings): Just look in hash table.

From-SVN: r248159
This commit is contained in:
Nathan Sidwell 2017-05-17 15:41:23 +00:00 • committed by Nathan Sidwell
parent e5b1f5a1d1
commit 539f481a29
3 changed files with 102 additions and 126 deletions
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10
gcc/cp/ChangeLog
View file

@ -1,3 +1,13 @@
2017-05-17 Nathan Sidwell <nathan@acm.org>
* cp-tree.h (default_hash_traits <lang_identifier *>): New
specialization.
* name-lookup.c (lookup_extern_c_fun_in_all_ns): Delete.
(extern_c_fns): New hash table.
(check_extern_c_conflict): New, broken out of ...
(pushdecl_maybe_friend_1): ... here. Call it.
(c_linkage_bindings): Just look in hash table.
2017-05-17 Ville Voutilainen <ville.voutilainen@gmail.com>
PR c++/80654

20
gcc/cp/cp-tree.h
View file

@ -535,6 +535,26 @@ identifier_p (tree t)
return NULL;
}
/* Hash trait specialization for lang_identifiers. This allows
PCH-safe maps keyed by DECL_NAME. If it wasn't for PCH, we could
just use a regular tree key. */
template <>
struct default_hash_traits <lang_identifier *>
: pointer_hash <tree_node>, ggc_remove <tree>
{
/* Use a regular tree as the type, to make using the hash table
simpler. We'll get dynamic type checking with the hash function
itself. */
GTY((skip)) typedef tree value_type;
GTY((skip)) typedef tree compare_type;
static hashval_t hash (const value_type &id)
{
return IDENTIFIER_HASH_VALUE (id);
}
};
/* In an IDENTIFIER_NODE, nonzero if this identifier is actually a
keyword. C_RID_CODE (node) is then the RID_* value of the keyword. */

198
gcc/cp/name-lookup.c
View file

@ -60,7 +60,6 @@ static void consider_binding_level (tree name,
enum lookup_name_fuzzy_kind kind);
static tree lookup_type_current_level (tree);
static tree push_using_directive (tree);
static tree lookup_extern_c_fun_in_all_ns (tree);
static void diagnose_name_conflict (tree, tree);
/* Add DECL to the list of things declared in B. */
@ -1184,6 +1183,75 @@ supplement_binding (cxx_binding *binding, tree decl)
return ret;
}
/* Map of identifiers to extern C functions (or LISTS thereof). */
static GTY(()) hash_map<lang_identifier *, tree> *extern_c_fns;
/* DECL has C linkage. If we have an existing instance, make sure it
has the same exception specification [7.5, 7.6]. If there's no
instance, add DECL to the map. */
static void
check_extern_c_conflict (tree decl)
{
/* Ignore artificial or system header decls. */
if (DECL_ARTIFICIAL (decl) || DECL_IN_SYSTEM_HEADER (decl))
return;
if (!extern_c_fns)
extern_c_fns = hash_map<lang_identifier *,tree>::create_ggc (127);
bool existed;
tree *slot = &extern_c_fns->get_or_insert (DECL_NAME (decl), &existed);
if (!existed)
*slot = decl;
else
{
tree old = *slot;
if (TREE_CODE (old) == TREE_LIST)
old = TREE_VALUE (old);
int mismatch = 0;
if (DECL_CONTEXT (old) == DECL_CONTEXT (decl))
; /* If they're in the same context, we'll have already complained
about a (possible) mismatch, when inserting the decl. */
else if (!decls_match (decl, old))
mismatch = 1;
else if (!comp_except_specs (TYPE_RAISES_EXCEPTIONS (TREE_TYPE (old)),
TYPE_RAISES_EXCEPTIONS (TREE_TYPE (decl)),
ce_normal))
mismatch = -1;
else if (DECL_ASSEMBLER_NAME_SET_P (old))
SET_DECL_ASSEMBLER_NAME (decl, DECL_ASSEMBLER_NAME (old));
if (mismatch)
{
pedwarn (input_location, 0,
"declaration of %q#D with C language linkage", decl);
pedwarn (DECL_SOURCE_LOCATION (old), 0,
"conflicts with previous declaration %q#D", old);
if (mismatch < 0)
pedwarn (input_location, 0,
"due to different exception specifications");
}
else
/* Chain it on for c_linkage_binding's use. */
*slot = tree_cons (NULL_TREE, decl, *slot);
}
}
/* Returns a list of C-linkage decls with the name NAME. Used in
c-family/c-pragma.c to implement redefine_extname pragma. */
tree
c_linkage_bindings (tree name)
{
if (extern_c_fns)
if (tree *slot = extern_c_fns->get (name))
return *slot;
return NULL_TREE;
}
/* DECL is being declared at a local scope. Emit suitable shadow
warnings. */
@ -1591,63 +1659,6 @@ pushdecl_maybe_friend_1 (tree x, bool is_friend)
}
}
/* If x has C linkage-specification, (extern "C"),
lookup its binding, in case it's already bound to an object.
The lookup is done in all namespaces.
If we find an existing binding, make sure it has the same
exception specification as x, otherwise, bail in error [7.5, 7.6]. */
if ((TREE_CODE (x) == FUNCTION_DECL)
&& DECL_EXTERN_C_P (x)
/* We should ignore declarations happening in system headers. */
&& !DECL_ARTIFICIAL (x)
&& !DECL_IN_SYSTEM_HEADER (x))
{
tree previous = lookup_extern_c_fun_in_all_ns (x);
if (previous
&& !DECL_ARTIFICIAL (previous)
&& !DECL_IN_SYSTEM_HEADER (previous)
&& DECL_CONTEXT (previous) != DECL_CONTEXT (x))
{
/* In case either x or previous is declared to throw an exception,
make sure both exception specifications are equal. */
if (decls_match (x, previous))
{
tree x_exception_spec = NULL_TREE;
tree previous_exception_spec = NULL_TREE;
x_exception_spec =
TYPE_RAISES_EXCEPTIONS (TREE_TYPE (x));
previous_exception_spec =
TYPE_RAISES_EXCEPTIONS (TREE_TYPE (previous));
if (!comp_except_specs (previous_exception_spec,
x_exception_spec,
ce_normal))
{
pedwarn (input_location, 0,
"declaration of %q#D with C language linkage",
x);
pedwarn (DECL_SOURCE_LOCATION (previous), 0,
"conflicts with previous declaration %q#D",
previous);
pedwarn (input_location, 0,
"due to different exception specifications");
return error_mark_node;
}
if (DECL_ASSEMBLER_NAME_SET_P (previous))
SET_DECL_ASSEMBLER_NAME (x,
DECL_ASSEMBLER_NAME (previous));
}
else
{
pedwarn (input_location, 0,
"declaration of %q#D with C language linkage", x);
pedwarn (DECL_SOURCE_LOCATION (previous), 0,
"conflicts with previous declaration %q#D",
previous);
}
}
}
check_template_shadow (x);
/* If this is a function conjured up by the back end, massage it
@ -1848,6 +1859,9 @@ pushdecl_maybe_friend_1 (tree x, bool is_friend)
if (VAR_P (x))
maybe_register_incomplete_var (x);
if (TREE_CODE (x) == FUNCTION_DECL && DECL_EXTERN_C_P (x))
/* We need to check and register the fn now. */
check_extern_c_conflict (x);
}
if (need_new_binding)
@ -2722,74 +2736,6 @@ binding_for_name (cp_binding_level *scope, tree name)
return result;
}
/* Walk through the bindings associated to the name of FUNCTION,
and return the first declaration of a function with a
"C" linkage specification, a.k.a 'extern "C"'.
This function looks for the binding, regardless of which scope it
has been defined in. It basically looks in all the known scopes.
Note that this function does not lookup for bindings of builtin functions
or for functions declared in system headers. */
static tree
lookup_extern_c_fun_in_all_ns (tree function)
{
tree name;
cxx_binding *iter;
gcc_assert (function && TREE_CODE (function) == FUNCTION_DECL);
name = DECL_NAME (function);
gcc_assert (name && identifier_p (name));
for (iter = IDENTIFIER_NAMESPACE_BINDINGS (name);
iter;
iter = iter->previous)
{
tree ovl;
for (ovl = iter->value; ovl; ovl = OVL_NEXT (ovl))
{
tree decl = OVL_CURRENT (ovl);
if (decl
&& TREE_CODE (decl) == FUNCTION_DECL
&& DECL_EXTERN_C_P (decl)
&& !DECL_ARTIFICIAL (decl))
{
return decl;
}
}
}
return NULL;
}
/* Returns a list of C-linkage decls with the name NAME. */
tree
c_linkage_bindings (tree name)
{
tree decls = NULL_TREE;
cxx_binding *iter;
for (iter = IDENTIFIER_NAMESPACE_BINDINGS (name);
iter;
iter = iter->previous)
{
tree ovl;
for (ovl = iter->value; ovl; ovl = OVL_NEXT (ovl))
{
tree decl = OVL_CURRENT (ovl);
if (decl
&& DECL_EXTERN_C_P (decl)
&& !DECL_ARTIFICIAL (decl))
{
if (decls == NULL_TREE)
decls = decl;
else
decls = tree_cons (NULL_TREE, decl, decls);
}
}
}
return decls;
}
/* Insert another USING_DECL into the current binding level, returning
this declaration. If this is a redeclaration, do nothing, and
return NULL_TREE if this not in namespace scope (in namespace