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/* Handle parameterized types (templates) for GNU C++.
Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
2001, 2002, 2003, 2004 Free Software Foundation, Inc.
Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
Rewritten by Jason Merrill (jason@cygnus.com).
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
GCC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING. If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
/* Known bugs or deficiencies include:
all methods must be provided in header files; can't use a source
file that contains only the method templates and "just win". */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "obstack.h"
#include "tree.h"
#include "flags.h"
#include "cp-tree.h"
#include "tree-inline.h"
#include "decl.h"
#include "lex.h"
#include "output.h"
#include "except.h"
#include "toplev.h"
#include "rtl.h"
#include "timevar.h"
/* The type of functions taking a tree, and some additional data, and
returning an int. */
typedef int (*tree_fn_t) (tree, void*);
/* The PENDING_TEMPLATES is a TREE_LIST of templates whose
instantiations have been deferred, either because their definitions
were not yet available, or because we were putting off doing the work.
The TREE_PURPOSE of each entry is either a DECL (for a function or
static data member), or a TYPE (for a class) indicating what we are
hoping to instantiate. The TREE_VALUE is not used. */
static GTY(()) tree pending_templates;
static GTY(()) tree last_pending_template;
int processing_template_parmlist;
static int template_header_count;
static GTY(()) tree saved_trees;
static GTY(()) varray_type inline_parm_levels;
static size_t inline_parm_levels_used;
static GTY(()) tree current_tinst_level;
static GTY(()) tree saved_access_scope;
/* A map from local variable declarations in the body of the template
presently being instantiated to the corresponding instantiated
local variables. */
static htab_t local_specializations;
#define UNIFY_ALLOW_NONE 0
#define UNIFY_ALLOW_MORE_CV_QUAL 1
#define UNIFY_ALLOW_LESS_CV_QUAL 2
#define UNIFY_ALLOW_DERIVED 4
#define UNIFY_ALLOW_INTEGER 8
#define UNIFY_ALLOW_OUTER_LEVEL 16
#define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
#define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
#define UNIFY_ALLOW_MAX_CORRECTION 128
#define GTB_VIA_VIRTUAL 1 /* The base class we are examining is
virtual, or a base class of a virtual
base. */
#define GTB_IGNORE_TYPE 2 /* We don't need to try to unify the current
type with the desired type. */
static void push_access_scope (tree);
static void pop_access_scope (tree);
static int resolve_overloaded_unification (tree, tree, tree, tree,
unification_kind_t, int);
static int try_one_overload (tree, tree, tree, tree, tree,
unification_kind_t, int, bool);
static int unify (tree, tree, tree, tree, int);
static void add_pending_template (tree);
static void reopen_tinst_level (tree);
static tree classtype_mangled_name (tree);
static char* mangle_class_name_for_template (const char *, tree, tree);
static tree tsubst_initializer_list (tree, tree);
static tree get_class_bindings (tree, tree, tree);
static tree coerce_template_parms (tree, tree, tree, tsubst_flags_t, int);
static void tsubst_enum (tree, tree, tree);
static tree add_to_template_args (tree, tree);
static tree add_outermost_template_args (tree, tree);
static bool check_instantiated_args (tree, tree, tsubst_flags_t);
static int maybe_adjust_types_for_deduction (unification_kind_t, tree*, tree*);
static int type_unification_real (tree, tree, tree, tree,
int, unification_kind_t, int, int);
static void note_template_header (int);
static tree convert_nontype_argument (tree, tree);
static tree convert_template_argument (tree, tree, tree,
tsubst_flags_t, int, tree);
static tree get_bindings_overload (tree, tree, tree);
static int for_each_template_parm (tree, tree_fn_t, void*, htab_t);
static tree build_template_parm_index (int, int, int, tree, tree);
static int inline_needs_template_parms (tree);
static void push_inline_template_parms_recursive (tree, int);
static tree retrieve_specialization (tree, tree);
static tree retrieve_local_specialization (tree);
static tree register_specialization (tree, tree, tree);
static void register_local_specialization (tree, tree);
static tree reduce_template_parm_level (tree, tree, int);
static tree build_template_decl (tree, tree);
static int mark_template_parm (tree, void *);
static int template_parm_this_level_p (tree, void *);
static tree tsubst_friend_function (tree, tree);
static tree tsubst_friend_class (tree, tree);
static int can_complete_type_without_circularity (tree);
static tree get_bindings (tree, tree, tree);
static tree get_bindings_real (tree, tree, tree, int, int, int);
static int template_decl_level (tree);
static int check_cv_quals_for_unify (int, tree, tree);
static tree tsubst_template_arg (tree, tree, tsubst_flags_t, tree);
static tree tsubst_template_args (tree, tree, tsubst_flags_t, tree);
static tree tsubst_template_parms (tree, tree, tsubst_flags_t);
static void regenerate_decl_from_template (tree, tree);
static tree most_specialized (tree, tree, tree);
static tree most_specialized_class (tree, tree);
static int template_class_depth_real (tree, int);
static tree tsubst_aggr_type (tree, tree, tsubst_flags_t, tree, int);
static tree tsubst_decl (tree, tree, tree, tsubst_flags_t);
static tree tsubst_arg_types (tree, tree, tsubst_flags_t, tree);
static tree tsubst_function_type (tree, tree, tsubst_flags_t, tree);
static void check_specialization_scope (void);
static tree process_partial_specialization (tree);
static void set_current_access_from_decl (tree);
static void check_default_tmpl_args (tree, tree, int, int);
static tree tsubst_call_declarator_parms (tree, tree, tsubst_flags_t, tree);
static tree get_template_base_recursive (tree, tree, tree, tree, tree, int);
static tree get_template_base (tree, tree, tree, tree);
static int verify_class_unification (tree, tree, tree);
static tree try_class_unification (tree, tree, tree, tree);
static int coerce_template_template_parms (tree, tree, tsubst_flags_t,
tree, tree);
static tree determine_specialization (tree, tree, tree *, int);
static int template_args_equal (tree, tree);
static void tsubst_default_arguments (tree);
static tree for_each_template_parm_r (tree *, int *, void *);
static tree copy_default_args_to_explicit_spec_1 (tree, tree);
static void copy_default_args_to_explicit_spec (tree);
static int invalid_nontype_parm_type_p (tree, tsubst_flags_t);
static int eq_local_specializations (const void *, const void *);
static bool dependent_type_p_r (tree);
static tree tsubst (tree, tree, tsubst_flags_t, tree);
static tree tsubst_expr (tree, tree, tsubst_flags_t, tree);
static tree tsubst_copy (tree, tree, tsubst_flags_t, tree);
/* Make the current scope suitable for access checking when we are
processing T. T can be FUNCTION_DECL for instantiated function
template, or VAR_DECL for static member variable (need by
instantiate_decl). */
static void
push_access_scope (tree t)
{
my_friendly_assert (TREE_CODE (t) == FUNCTION_DECL
|| TREE_CODE (t) == VAR_DECL,
0);
if (DECL_CLASS_SCOPE_P (t))
push_nested_class (DECL_CONTEXT (t));
else
push_to_top_level ();
if (TREE_CODE (t) == FUNCTION_DECL)
{
saved_access_scope = tree_cons
(NULL_TREE, current_function_decl, saved_access_scope);
current_function_decl = t;
}
}
/* Restore the scope set up by push_access_scope. T is the node we
are processing. */
static void
pop_access_scope (tree t)
{
if (TREE_CODE (t) == FUNCTION_DECL)
{
current_function_decl = TREE_VALUE (saved_access_scope);
saved_access_scope = TREE_CHAIN (saved_access_scope);
}
if (DECL_CLASS_SCOPE_P (t))
pop_nested_class ();
else
pop_from_top_level ();
}
/* Do any processing required when DECL (a member template
declaration) is finished. Returns the TEMPLATE_DECL corresponding
to DECL, unless it is a specialization, in which case the DECL
itself is returned. */
tree
finish_member_template_decl (tree decl)
{
if (decl == error_mark_node)
return error_mark_node;
my_friendly_assert (DECL_P (decl), 20020812);
if (TREE_CODE (decl) == TYPE_DECL)
{
tree type;
type = TREE_TYPE (decl);
if (IS_AGGR_TYPE (type)
&& CLASSTYPE_TEMPLATE_INFO (type)
&& !CLASSTYPE_TEMPLATE_SPECIALIZATION (type))
{
tree tmpl = CLASSTYPE_TI_TEMPLATE (type);
check_member_template (tmpl);
return tmpl;
}
return NULL_TREE;
}
else if (TREE_CODE (decl) == FIELD_DECL)
error ("data member `%D' cannot be a member template", decl);
else if (DECL_TEMPLATE_INFO (decl))
{
if (!DECL_TEMPLATE_SPECIALIZATION (decl))
{
check_member_template (DECL_TI_TEMPLATE (decl));
return DECL_TI_TEMPLATE (decl);
}
else
return decl;
}
else
error ("invalid member template declaration `%D'", decl);
return error_mark_node;
}
/* Returns the template nesting level of the indicated class TYPE.
For example, in:
template <class T>
struct A
{
template <class U>
struct B {};
};
A<T>::B<U> has depth two, while A<T> has depth one.
Both A<T>::B<int> and A<int>::B<U> have depth one, if
COUNT_SPECIALIZATIONS is 0 or if they are instantiations, not
specializations.
This function is guaranteed to return 0 if passed NULL_TREE so
that, for example, `template_class_depth (current_class_type)' is
always safe. */
static int
template_class_depth_real (tree type, int count_specializations)
{
int depth;
for (depth = 0;
type && TREE_CODE (type) != NAMESPACE_DECL;
type = (TREE_CODE (type) == FUNCTION_DECL)
? CP_DECL_CONTEXT (type) : TYPE_CONTEXT (type))
{
if (TREE_CODE (type) != FUNCTION_DECL)
{
if (CLASSTYPE_TEMPLATE_INFO (type)
&& PRIMARY_TEMPLATE_P (CLASSTYPE_TI_TEMPLATE (type))
&& ((count_specializations
&& CLASSTYPE_TEMPLATE_SPECIALIZATION (type))
|| uses_template_parms (CLASSTYPE_TI_ARGS (type))))
++depth;
}
else
{
if (DECL_TEMPLATE_INFO (type)
&& PRIMARY_TEMPLATE_P (DECL_TI_TEMPLATE (type))
&& ((count_specializations
&& DECL_TEMPLATE_SPECIALIZATION (type))
|| uses_template_parms (DECL_TI_ARGS (type))))
++depth;
}
}
return depth;
}
/* Returns the template nesting level of the indicated class TYPE.
Like template_class_depth_real, but instantiations do not count in
the depth. */
int
template_class_depth (tree type)
{
return template_class_depth_real (type, /*count_specializations=*/0);
}
/* Returns 1 if processing DECL as part of do_pending_inlines
needs us to push template parms. */
static int
inline_needs_template_parms (tree decl)
{
if (! DECL_TEMPLATE_INFO (decl))
return 0;
return (TMPL_PARMS_DEPTH (DECL_TEMPLATE_PARMS (most_general_template (decl)))
> (processing_template_decl + DECL_TEMPLATE_SPECIALIZATION (decl)));
}
/* Subroutine of maybe_begin_member_template_processing.
Push the template parms in PARMS, starting from LEVELS steps into the
chain, and ending at the beginning, since template parms are listed
innermost first. */
static void
push_inline_template_parms_recursive (tree parmlist, int levels)
{
tree parms = TREE_VALUE (parmlist);
int i;
if (levels > 1)
push_inline_template_parms_recursive (TREE_CHAIN (parmlist), levels - 1);
++processing_template_decl;
current_template_parms
= tree_cons (size_int (processing_template_decl),
parms, current_template_parms);
TEMPLATE_PARMS_FOR_INLINE (current_template_parms) = 1;
begin_scope (TREE_VEC_LENGTH (parms) ? sk_template_parms : sk_template_spec,
NULL);
for (i = 0; i < TREE_VEC_LENGTH (parms); ++i)
{
tree parm = TREE_VALUE (TREE_VEC_ELT (parms, i));
my_friendly_assert (DECL_P (parm), 0);
switch (TREE_CODE (parm))
{
case TYPE_DECL:
case TEMPLATE_DECL:
pushdecl (parm);
break;
case PARM_DECL:
{
/* Make a CONST_DECL as is done in process_template_parm.
It is ugly that we recreate this here; the original
version built in process_template_parm is no longer
available. */
tree decl = build_decl (CONST_DECL, DECL_NAME (parm),
TREE_TYPE (parm));
DECL_ARTIFICIAL (decl) = 1;
TREE_CONSTANT (decl) = TREE_READONLY (decl) = 1;
DECL_INITIAL (decl) = DECL_INITIAL (parm);
SET_DECL_TEMPLATE_PARM_P (decl);
pushdecl (decl);
}
break;
default:
abort ();
}
}
}
/* Restore the template parameter context for a member template or
a friend template defined in a class definition. */
void
maybe_begin_member_template_processing (tree decl)
{
tree parms;
int levels = 0;
if (inline_needs_template_parms (decl))
{
parms = DECL_TEMPLATE_PARMS (most_general_template (decl));
levels = TMPL_PARMS_DEPTH (parms) - processing_template_decl;
if (DECL_TEMPLATE_SPECIALIZATION (decl))
{
--levels;
parms = TREE_CHAIN (parms);
}
push_inline_template_parms_recursive (parms, levels);
}
/* Remember how many levels of template parameters we pushed so that
we can pop them later. */
if (!inline_parm_levels)
VARRAY_INT_INIT (inline_parm_levels, 4, "inline_parm_levels");
if (inline_parm_levels_used == inline_parm_levels->num_elements)
VARRAY_GROW (inline_parm_levels, 2 * inline_parm_levels_used);
VARRAY_INT (inline_parm_levels, inline_parm_levels_used) = levels;
++inline_parm_levels_used;
}
/* Undo the effects of begin_member_template_processing. */
void
maybe_end_member_template_processing (void)
{
int i;
if (!inline_parm_levels_used)
return;
--inline_parm_levels_used;
for (i = 0;
i < VARRAY_INT (inline_parm_levels, inline_parm_levels_used);
++i)
{
--processing_template_decl;
current_template_parms = TREE_CHAIN (current_template_parms);
poplevel (0, 0, 0);
}
}
/* Returns nonzero iff T is a member template function. We must be
careful as in
template <class T> class C { void f(); }
Here, f is a template function, and a member, but not a member
template. This function does not concern itself with the origin of
T, only its present state. So if we have
template <class T> class C { template <class U> void f(U); }
then neither C<int>::f<char> nor C<T>::f<double> is considered
to be a member template. But, `template <class U> void
C<int>::f(U)' is considered a member template. */
int
is_member_template (tree t)
{
if (!DECL_FUNCTION_TEMPLATE_P (t))
/* Anything that isn't a function or a template function is
certainly not a member template. */
return 0;
/* A local class can't have member templates. */
if (decl_function_context (t))
return 0;
return (DECL_FUNCTION_MEMBER_P (DECL_TEMPLATE_RESULT (t))
/* If there are more levels of template parameters than
there are template classes surrounding the declaration,
then we have a member template. */
&& (TMPL_PARMS_DEPTH (DECL_TEMPLATE_PARMS (t)) >
template_class_depth (DECL_CONTEXT (t))));
}
#if 0 /* UNUSED */
/* Returns nonzero iff T is a member template class. See
is_member_template for a description of what precisely constitutes
a member template. */
int
is_member_template_class (tree t)
{
if (!DECL_CLASS_TEMPLATE_P (t))
/* Anything that isn't a class template, is certainly not a member
template. */
return 0;
if (!DECL_CLASS_SCOPE_P (t))
/* Anything whose context isn't a class type is surely not a
member template. */
return 0;
/* If there are more levels of template parameters than there are
template classes surrounding the declaration, then we have a
member template. */
return (TMPL_PARMS_DEPTH (DECL_TEMPLATE_PARMS (t)) >
template_class_depth (DECL_CONTEXT (t)));
}
#endif
/* Return a new template argument vector which contains all of ARGS,
but has as its innermost set of arguments the EXTRA_ARGS. */
static tree
add_to_template_args (tree args, tree extra_args)
{
tree new_args;
int extra_depth;
int i;
int j;
extra_depth = TMPL_ARGS_DEPTH (extra_args);
new_args = make_tree_vec (TMPL_ARGS_DEPTH (args) + extra_depth);
for (i = 1; i <= TMPL_ARGS_DEPTH (args); ++i)
SET_TMPL_ARGS_LEVEL (new_args, i, TMPL_ARGS_LEVEL (args, i));
for (j = 1; j <= extra_depth; ++j, ++i)
SET_TMPL_ARGS_LEVEL (new_args, i, TMPL_ARGS_LEVEL (extra_args, j));
return new_args;
}
/* Like add_to_template_args, but only the outermost ARGS are added to
the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
(EXTRA_ARGS) levels are added. This function is used to combine
the template arguments from a partial instantiation with the
template arguments used to attain the full instantiation from the
partial instantiation. */
static tree
add_outermost_template_args (tree args, tree extra_args)
{
tree new_args;
/* If there are more levels of EXTRA_ARGS than there are ARGS,
something very fishy is going on. */
my_friendly_assert (TMPL_ARGS_DEPTH (args) >= TMPL_ARGS_DEPTH (extra_args),
0);
/* If *all* the new arguments will be the EXTRA_ARGS, just return
them. */
if (TMPL_ARGS_DEPTH (args) == TMPL_ARGS_DEPTH (extra_args))
return extra_args;
/* For the moment, we make ARGS look like it contains fewer levels. */
TREE_VEC_LENGTH (args) -= TMPL_ARGS_DEPTH (extra_args);
new_args = add_to_template_args (args, extra_args);
/* Now, we restore ARGS to its full dimensions. */
TREE_VEC_LENGTH (args) += TMPL_ARGS_DEPTH (extra_args);
return new_args;
}
/* Return the N levels of innermost template arguments from the ARGS. */
tree
get_innermost_template_args (tree args, int n)
{
tree new_args;
int extra_levels;
int i;
my_friendly_assert (n >= 0, 20000603);
/* If N is 1, just return the innermost set of template arguments. */
if (n == 1)
return TMPL_ARGS_LEVEL (args, TMPL_ARGS_DEPTH (args));
/* If we're not removing anything, just return the arguments we were
given. */
extra_levels = TMPL_ARGS_DEPTH (args) - n;
my_friendly_assert (extra_levels >= 0, 20000603);
if (extra_levels == 0)
return args;
/* Make a new set of arguments, not containing the outer arguments. */
new_args = make_tree_vec (n);
for (i = 1; i <= n; ++i)
SET_TMPL_ARGS_LEVEL (new_args, i,
TMPL_ARGS_LEVEL (args, i + extra_levels));
return new_args;
}
/* We've got a template header coming up; push to a new level for storing
the parms. */
void
begin_template_parm_list (void)
{
/* We use a non-tag-transparent scope here, which causes pushtag to
put tags in this scope, rather than in the enclosing class or
namespace scope. This is the right thing, since we want
TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
global template class, push_template_decl handles putting the
TEMPLATE_DECL into top-level scope. For a nested template class,
e.g.:
template <class T> struct S1 {
template <class T> struct S2 {};
};
pushtag contains special code to call pushdecl_with_scope on the
TEMPLATE_DECL for S2. */
begin_scope (sk_template_parms, NULL);
++processing_template_decl;
++processing_template_parmlist;
note_template_header (0);
}
/* This routine is called when a specialization is declared. If it is
invalid to declare a specialization here, an error is reported. */
static void
check_specialization_scope (void)
{
tree scope = current_scope ();
/* [temp.expl.spec]
An explicit specialization shall be declared in the namespace of
which the template is a member, or, for member templates, in the
namespace of which the enclosing class or enclosing class
template is a member. An explicit specialization of a member
function, member class or static data member of a class template
shall be declared in the namespace of which the class template
is a member. */
if (scope && TREE_CODE (scope) != NAMESPACE_DECL)
error ("explicit specialization in non-namespace scope `%D'",
scope);
/* [temp.expl.spec]
In an explicit specialization declaration for a member of a class
template or a member template that appears in namespace scope,
the member template and some of its enclosing class templates may
remain unspecialized, except that the declaration shall not
explicitly specialize a class member template if its enclosing
class templates are not explicitly specialized as well. */
if (current_template_parms)
error ("enclosing class templates are not explicitly specialized");
}
/* We've just seen template <>. */
void
begin_specialization (void)
{
begin_scope (sk_template_spec, NULL);
note_template_header (1);
check_specialization_scope ();
}
/* Called at then end of processing a declaration preceded by
template<>. */
void
end_specialization (void)
{
finish_scope ();
reset_specialization ();
}
/* Any template <>'s that we have seen thus far are not referring to a
function specialization. */
void
reset_specialization (void)
{
processing_specialization = 0;
template_header_count = 0;
}
/* We've just seen a template header. If SPECIALIZATION is nonzero,
it was of the form template <>. */
static void
note_template_header (int specialization)
{
processing_specialization = specialization;
template_header_count++;
}
/* We're beginning an explicit instantiation. */
void
begin_explicit_instantiation (void)
{
my_friendly_assert (!processing_explicit_instantiation, 20020913);
processing_explicit_instantiation = true;
}
void
end_explicit_instantiation (void)
{
my_friendly_assert(processing_explicit_instantiation, 20020913);
processing_explicit_instantiation = false;
}
/* A explicit specialization or partial specialization TMPL is being
declared. Check that the namespace in which the specialization is
occurring is permissible. Returns false iff it is invalid to
specialize TMPL in the current namespace. */
static bool
check_specialization_namespace (tree tmpl)
{
tree tpl_ns = decl_namespace_context (tmpl);
/* [tmpl.expl.spec]
An explicit specialization shall be declared in the namespace of
which the template is a member, or, for member templates, in the
namespace of which the enclosing class or enclosing class
template is a member. An explicit specialization of a member
function, member class or static data member of a class template
shall be declared in the namespace of which the class template is
a member. */
if (is_associated_namespace (current_namespace, tpl_ns))
/* Same or super-using namespace. */
return true;
else
{
pedwarn ("specialization of `%D' in different namespace", tmpl);
cp_pedwarn_at (" from definition of `%#D'", tmpl);
return false;
}
}
/* The TYPE is being declared. If it is a template type, that means it
is a partial specialization. Do appropriate error-checking. */
void
maybe_process_partial_specialization (tree type)
{
/* TYPE maybe an ERROR_MARK_NODE. */
tree context = TYPE_P (type) ? TYPE_CONTEXT (type) : NULL_TREE;
if (CLASS_TYPE_P (type) && CLASSTYPE_USE_TEMPLATE (type))
{
/* This is for ordinary explicit specialization and partial
specialization of a template class such as:
template <> class C<int>;
or:
template <class T> class C<T*>;
Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
if (CLASSTYPE_IMPLICIT_INSTANTIATION (type)
&& !COMPLETE_TYPE_P (type))
{
check_specialization_namespace (CLASSTYPE_TI_TEMPLATE (type));
SET_CLASSTYPE_TEMPLATE_SPECIALIZATION (type);
if (processing_template_decl)
push_template_decl (TYPE_MAIN_DECL (type));
}
else if (CLASSTYPE_TEMPLATE_INSTANTIATION (type))
error ("specialization of `%T' after instantiation", type);
}
else if (CLASS_TYPE_P (type)
&& !CLASSTYPE_USE_TEMPLATE (type)
&& CLASSTYPE_TEMPLATE_INFO (type)
&& context && CLASS_TYPE_P (context)
&& CLASSTYPE_TEMPLATE_INFO (context))
{
/* This is for an explicit specialization of member class
template according to [temp.expl.spec/18]:
template <> template <class U> class C<int>::D;
The context `C<int>' must be an implicit instantiation.
Otherwise this is just a member class template declared
earlier like:
template <> class C<int> { template <class U> class D; };
template <> template <class U> class C<int>::D;
In the first case, `C<int>::D' is a specialization of `C<T>::D'
while in the second case, `C<int>::D' is a primary template
and `C<T>::D' may not exist. */
if (CLASSTYPE_IMPLICIT_INSTANTIATION (context)
&& !COMPLETE_TYPE_P (type))
{
tree t;
if (current_namespace
!= decl_namespace_context (CLASSTYPE_TI_TEMPLATE (type)))
{
pedwarn ("specializing `%#T' in different namespace", type);
cp_pedwarn_at (" from definition of `%#D'",
CLASSTYPE_TI_TEMPLATE (type));
}
/* Check for invalid specialization after instantiation:
template <> template <> class C<int>::D<int>;
template <> template <class U> class C<int>::D; */
for (t = DECL_TEMPLATE_INSTANTIATIONS
(most_general_template (CLASSTYPE_TI_TEMPLATE (type)));
t; t = TREE_CHAIN (t))
if (TREE_VALUE (t) != type
&& TYPE_CONTEXT (TREE_VALUE (t)) == context)
error ("specialization `%T' after instantiation `%T'",
type, TREE_VALUE (t));
/* Mark TYPE as a specialization. And as a result, we only
have one level of template argument for the innermost
class template. */
SET_CLASSTYPE_TEMPLATE_SPECIALIZATION (type);
CLASSTYPE_TI_ARGS (type)
= INNERMOST_TEMPLATE_ARGS (CLASSTYPE_TI_ARGS (type));
}
}
else if (processing_specialization)
error ("explicit specialization of non-template `%T'", type);
}
/* Retrieve the specialization (in the sense of [temp.spec] - a
specialization is either an instantiation or an explicit
specialization) of TMPL for the given template ARGS. If there is
no such specialization, return NULL_TREE. The ARGS are a vector of
arguments, or a vector of vectors of arguments, in the case of
templates with more than one level of parameters. */
static tree
retrieve_specialization (tree tmpl, tree args)
{
tree s;
my_friendly_assert (TREE_CODE (tmpl) == TEMPLATE_DECL, 0);
/* There should be as many levels of arguments as there are
levels of parameters. */
my_friendly_assert (TMPL_ARGS_DEPTH (args)
== TMPL_PARMS_DEPTH (DECL_TEMPLATE_PARMS (tmpl)),
0);
for (s = DECL_TEMPLATE_SPECIALIZATIONS (tmpl);
s != NULL_TREE;
s = TREE_CHAIN (s))
if (comp_template_args (TREE_PURPOSE (s), args))
return TREE_VALUE (s);
return NULL_TREE;
}
/* Like retrieve_specialization, but for local declarations. */
static tree
retrieve_local_specialization (tree tmpl)
{
tree spec = htab_find_with_hash (local_specializations, tmpl,
htab_hash_pointer (tmpl));
return spec ? TREE_PURPOSE (spec) : NULL_TREE;
}
/* Returns nonzero iff DECL is a specialization of TMPL. */
int
is_specialization_of (tree decl, tree tmpl)
{
tree t;
if (TREE_CODE (decl) == FUNCTION_DECL)
{
for (t = decl;
t != NULL_TREE;
t = DECL_TEMPLATE_INFO (t) ? DECL_TI_TEMPLATE (t) : NULL_TREE)
if (t == tmpl)
return 1;
}
else
{
my_friendly_assert (TREE_CODE (decl) == TYPE_DECL, 0);
for (t = TREE_TYPE (decl);
t != NULL_TREE;
t = CLASSTYPE_USE_TEMPLATE (t)
? TREE_TYPE (CLASSTYPE_TI_TEMPLATE (t)) : NULL_TREE)
if (same_type_ignoring_top_level_qualifiers_p (t, TREE_TYPE (tmpl)))
return 1;
}
return 0;
}
/* Returns nonzero iff DECL is a specialization of friend declaration
FRIEND according to [temp.friend]. */
bool
is_specialization_of_friend (tree decl, tree friend)
{
bool need_template = true;
int template_depth;
my_friendly_assert (TREE_CODE (decl) == FUNCTION_DECL, 0);
/* For [temp.friend/6] when FRIEND is an ordinary member function
of a template class, we want to check if DECL is a specialization
if this. */
if (TREE_CODE (friend) == FUNCTION_DECL
&& DECL_TEMPLATE_INFO (friend)
&& !DECL_USE_TEMPLATE (friend))
{
friend = DECL_TI_TEMPLATE (friend);
need_template = false;
}
/* There is nothing to do if this is not a template friend. */
if (TREE_CODE (friend) != TEMPLATE_DECL)
return 0;
if (is_specialization_of (decl, friend))
return 1;
/* [temp.friend/6]
A member of a class template may be declared to be a friend of a
non-template class. In this case, the corresponding member of
every specialization of the class template is a friend of the
class granting friendship.
For example, given a template friend declaration
template <class T> friend void A<T>::f();
the member function below is considered a friend
template <> struct A<int> {
void f();
};
For this type of template friend, TEMPLATE_DEPTH below will be
nonzero. To determine if DECL is a friend of FRIEND, we first
check if the enclosing class is a specialization of another. */
template_depth = template_class_depth (DECL_CONTEXT (friend));
if (template_depth
&& DECL_CLASS_SCOPE_P (decl)
&& is_specialization_of (TYPE_NAME (DECL_CONTEXT (decl)),
CLASSTYPE_TI_TEMPLATE (DECL_CONTEXT (friend))))
{
/* Next, we check the members themselves. In order to handle
a few tricky cases like
template <class T> friend void A<T>::g(T t);
template <class T> template <T t> friend void A<T>::h();
we need to figure out what ARGS is (corresponding to `T' in above
examples) from DECL for later processing. */
tree context = DECL_CONTEXT (decl);
tree args = NULL_TREE;
int current_depth = 0;
while (current_depth < template_depth)
{
if (CLASSTYPE_TEMPLATE_INFO (context))
{
if (current_depth == 0)
args = TYPE_TI_ARGS (context);
else
args = add_to_template_args (TYPE_TI_ARGS (context), args);
current_depth++;
}
context = TYPE_CONTEXT (context);
}
if (TREE_CODE (decl) == FUNCTION_DECL)
{
bool is_template;
tree friend_type;
tree decl_type;
tree friend_args_type;
tree decl_args_type;
/* Make sure that both DECL and FRIEND are templates or
non-templates. */
is_template = DECL_TEMPLATE_INFO (decl)
&& PRIMARY_TEMPLATE_P (DECL_TI_TEMPLATE (decl));
if (need_template ^ is_template)
return 0;
else if (is_template)
{
/* If both are templates, check template parameter list. */
tree friend_parms
= tsubst_template_parms (DECL_TEMPLATE_PARMS (friend),
args, tf_none);
if (!comp_template_parms
(DECL_TEMPLATE_PARMS (DECL_TI_TEMPLATE (decl)),
friend_parms))
return 0;
decl_type = TREE_TYPE (DECL_TI_TEMPLATE (decl));
}
else
decl_type = TREE_TYPE (decl);
friend_type = tsubst_function_type (TREE_TYPE (friend), args,
tf_none, NULL_TREE);
if (friend_type == error_mark_node)
return 0;
/* Check if return types match. */
if (!same_type_p (TREE_TYPE (decl_type), TREE_TYPE (friend_type)))
return 0;
/* Check if function parameter types match, ignoring the
`this' parameter. */
friend_args_type = TYPE_ARG_TYPES (friend_type);
decl_args_type = TYPE_ARG_TYPES (decl_type);
if (DECL_NONSTATIC_MEMBER_FUNCTION_P (friend))
friend_args_type = TREE_CHAIN (friend_args_type);
if (DECL_NONSTATIC_MEMBER_FUNCTION_P (decl))
decl_args_type = TREE_CHAIN (decl_args_type);
if (compparms (decl_args_type, friend_args_type))
return 1;
}
}
return 0;
}
/* Register the specialization SPEC as a specialization of TMPL with
the indicated ARGS. Returns SPEC, or an equivalent prior
declaration, if available. */
static tree
register_specialization (tree spec, tree tmpl, tree args)
{
tree s;
my_friendly_assert (TREE_CODE (tmpl) == TEMPLATE_DECL, 0);
if (TREE_CODE (spec) == FUNCTION_DECL
&& uses_template_parms (DECL_TI_ARGS (spec)))
/* This is the FUNCTION_DECL for a partial instantiation. Don't
register it; we want the corresponding TEMPLATE_DECL instead.
We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
the more obvious `uses_template_parms (spec)' to avoid problems
with default function arguments. In particular, given
something like this:
template <class T> void f(T t1, T t = T())
the default argument expression is not substituted for in an
instantiation unless and until it is actually needed. */
return spec;
/* There should be as many levels of arguments as there are
levels of parameters. */
my_friendly_assert (TMPL_ARGS_DEPTH (args)
== TMPL_PARMS_DEPTH (DECL_TEMPLATE_PARMS (tmpl)),
0);
for (s = DECL_TEMPLATE_SPECIALIZATIONS (tmpl);
s != NULL_TREE;
s = TREE_CHAIN (s))
{
tree fn = TREE_VALUE (s);
/* We can sometimes try to re-register a specialization that we've
already got. In particular, regenerate_decl_from_template
calls duplicate_decls which will update the specialization
list. But, we'll still get called again here anyhow. It's
more convenient to simply allow this than to try to prevent it. */
if (fn == spec)
return spec;
else if (comp_template_args (TREE_PURPOSE (s), args))
{
if (DECL_TEMPLATE_SPECIALIZATION (spec))
{
if (DECL_TEMPLATE_INSTANTIATION (fn))
{
if (TREE_USED (fn)
|| DECL_EXPLICIT_INSTANTIATION (fn))
{
error ("specialization of %D after instantiation",
fn);
return spec;
}
else
{
/* This situation should occur only if the first
specialization is an implicit instantiation,
the second is an explicit specialization, and
the implicit instantiation has not yet been
used. That situation can occur if we have
implicitly instantiated a member function and
then specialized it later.
We can also wind up here if a friend
declaration that looked like an instantiation
turns out to be a specialization:
template <class T> void foo(T);
class S { friend void foo<>(int) };
template <> void foo(int);
We transform the existing DECL in place so that
any pointers to it become pointers to the
updated declaration.
If there was a definition for the template, but
not for the specialization, we want this to
look as if there is no definition, and vice
versa. */
DECL_INITIAL (fn) = NULL_TREE;
duplicate_decls (spec, fn);
return fn;
}
}
else if (DECL_TEMPLATE_SPECIALIZATION (fn))
{
if (!duplicate_decls (spec, fn) && DECL_INITIAL (spec))
/* Dup decl failed, but this is a new
definition. Set the line number so any errors
match this new definition. */
DECL_SOURCE_LOCATION (fn) = DECL_SOURCE_LOCATION (spec);
return fn;
}
}
}
}
/* A specialization must be declared in the same namespace as the
template it is specializing. */
if (DECL_TEMPLATE_SPECIALIZATION (spec)
&& !check_specialization_namespace (tmpl))
DECL_CONTEXT (spec) = decl_namespace_context (tmpl);
DECL_TEMPLATE_SPECIALIZATIONS (tmpl)
= tree_cons (args, spec, DECL_TEMPLATE_SPECIALIZATIONS (tmpl));
return spec;
}
/* Unregister the specialization SPEC as a specialization of TMPL.
Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
if the SPEC was listed as a specialization of TMPL. */
bool
reregister_specialization (tree spec, tree tmpl, tree new_spec)
{
tree* s;
for (s = &DECL_TEMPLATE_SPECIALIZATIONS (tmpl);
*s != NULL_TREE;
s = &TREE_CHAIN (*s))
if (TREE_VALUE (*s) == spec)
{
if (!new_spec)
*s = TREE_CHAIN (*s);
else
TREE_VALUE (*s) = new_spec;
return 1;
}
return 0;
}
/* Compare an entry in the local specializations hash table P1 (which
is really a pointer to a TREE_LIST) with P2 (which is really a
DECL). */
static int
eq_local_specializations (const void *p1, const void *p2)
{
return TREE_VALUE ((tree) p1) == (tree) p2;
}
/* Hash P1, an entry in the local specializations table. */
static hashval_t
hash_local_specialization (const void* p1)
{
return htab_hash_pointer (TREE_VALUE ((tree) p1));
}
/* Like register_specialization, but for local declarations. We are
registering SPEC, an instantiation of TMPL. */
static void
register_local_specialization (tree spec, tree tmpl)
{
void **slot;
slot = htab_find_slot_with_hash (local_specializations, tmpl,
htab_hash_pointer (tmpl), INSERT);
*slot = build_tree_list (spec, tmpl);
}
/* Print the list of candidate FNS in an error message. */
void
print_candidates (tree fns)
{
tree fn;
const char *str = "candidates are:";
for (fn = fns; fn != NULL_TREE; fn = TREE_CHAIN (fn))
{
tree f;
for (f = TREE_VALUE (fn); f; f = OVL_NEXT (f))
cp_error_at ("%s %+#D", str, OVL_CURRENT (f));
str = " ";
}
}
/* Returns the template (one of the functions given by TEMPLATE_ID)
which can be specialized to match the indicated DECL with the
explicit template args given in TEMPLATE_ID. The DECL may be
NULL_TREE if none is available. In that case, the functions in
TEMPLATE_ID are non-members.
If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
specialization of a member template.
The template args (those explicitly specified and those deduced)
are output in a newly created vector *TARGS_OUT.
If it is impossible to determine the result, an error message is
issued. The error_mark_node is returned to indicate failure. */
static tree
determine_specialization (tree template_id,
tree decl,
tree* targs_out,
int need_member_template)
{
tree fns;
tree targs;
tree explicit_targs;
tree candidates = NULL_TREE;
tree templates = NULL_TREE;
*targs_out = NULL_TREE;
if (template_id == error_mark_node)
return error_mark_node;
fns = TREE_OPERAND (template_id, 0);
explicit_targs = TREE_OPERAND (template_id, 1);
if (fns == error_mark_node)
return error_mark_node;
/* Check for baselinks. */
if (BASELINK_P (fns))
fns = BASELINK_FUNCTIONS (fns);
if (!is_overloaded_fn (fns))
{
error ("`%D' is not a function template", fns);
return error_mark_node;
}
for (; fns; fns = OVL_NEXT (fns))
{
tree fn = OVL_CURRENT (fns);
if (TREE_CODE (fn) == TEMPLATE_DECL)
{
tree decl_arg_types;
tree fn_arg_types;
/* DECL might be a specialization of FN. */
/* Adjust the type of DECL in case FN is a static member. */
decl_arg_types = TYPE_ARG_TYPES (TREE_TYPE (decl));
if (DECL_STATIC_FUNCTION_P (fn)
&& DECL_NONSTATIC_MEMBER_FUNCTION_P (decl))
decl_arg_types = TREE_CHAIN (decl_arg_types);
/* Check that the number of function parameters matches.
For example,
template <class T> void f(int i = 0);
template <> void f<int>();
The specialization f<int> is invalid but is not caught
by get_bindings below. */
fn_arg_types = TYPE_ARG_TYPES (TREE_TYPE (fn));
if (list_length (fn_arg_types) != list_length (decl_arg_types))
continue;
/* For a non-static member function, we need to make sure that
the const qualification is the same. This can be done by
checking the 'this' in the argument list. */
if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fn)
&& !same_type_p (TREE_VALUE (fn_arg_types),
TREE_VALUE (decl_arg_types)))
continue;
/* See whether this function might be a specialization of this
template. */
targs = get_bindings (fn, decl, explicit_targs);
if (!targs)
/* We cannot deduce template arguments that when used to
specialize TMPL will produce DECL. */
continue;
/* Save this template, and the arguments deduced. */
templates = tree_cons (targs, fn, templates);
}
else if (need_member_template)
/* FN is an ordinary member function, and we need a
specialization of a member template. */
;
else if (TREE_CODE (fn) != FUNCTION_DECL)
/* We can get IDENTIFIER_NODEs here in certain erroneous
cases. */
;
else if (!DECL_FUNCTION_MEMBER_P (fn))
/* This is just an ordinary non-member function. Nothing can
be a specialization of that. */
;
else if (DECL_ARTIFICIAL (fn))
/* Cannot specialize functions that are created implicitly. */
;
else
{
tree decl_arg_types;
/* This is an ordinary member function. However, since
we're here, we can assume it's enclosing class is a
template class. For example,
template <typename T> struct S { void f(); };
template <> void S<int>::f() {}
Here, S<int>::f is a non-template, but S<int> is a
template class. If FN has the same type as DECL, we
might be in business. */
if (!DECL_TEMPLATE_INFO (fn))
/* Its enclosing class is an explicit specialization
of a template class. This is not a candidate. */
continue;
if (!same_type_p (TREE_TYPE (TREE_TYPE (decl)),
TREE_TYPE (TREE_TYPE (fn))))
/* The return types differ. */
continue;
/* Adjust the type of DECL in case FN is a static member. */
decl_arg_types = TYPE_ARG_TYPES (TREE_TYPE (decl));
if (DECL_STATIC_FUNCTION_P (fn)
&& DECL_NONSTATIC_MEMBER_FUNCTION_P (decl))
decl_arg_types = TREE_CHAIN (decl_arg_types);
if (compparms (TYPE_ARG_TYPES (TREE_TYPE (fn)),
decl_arg_types))
/* They match! */
candidates = tree_cons (NULL_TREE, fn, candidates);
}
}
if (templates && TREE_CHAIN (templates))
{
/* We have:
[temp.expl.spec]
It is possible for a specialization with a given function
signature to be instantiated from more than one function
template. In such cases, explicit specification of the
template arguments must be used to uniquely identify the
function template specialization being specialized.
Note that here, there's no suggestion that we're supposed to
determine which of the candidate templates is most
specialized. However, we, also have:
[temp.func.order]
Partial ordering of overloaded function template
declarations is used in the following contexts to select
the function template to which a function template
specialization refers:
-- when an explicit specialization refers to a function
template.
So, we do use the partial ordering rules, at least for now.
This extension can only serve to make invalid programs valid,
so it's safe. And, there is strong anecdotal evidence that
the committee intended the partial ordering rules to apply;
the EDG front-end has that behavior, and John Spicer claims
that the committee simply forgot to delete the wording in
[temp.expl.spec]. */
tree tmpl = most_specialized (templates, decl, explicit_targs);
if (tmpl && tmpl != error_mark_node)
{
targs = get_bindings (tmpl, decl, explicit_targs);
templates = tree_cons (targs, tmpl, NULL_TREE);
}
}
if (templates == NULL_TREE && candidates == NULL_TREE)
{
cp_error_at ("template-id `%D' for `%+D' does not match any template declaration",
template_id, decl);
return error_mark_node;
}
else if ((templates && TREE_CHAIN (templates))
|| (candidates && TREE_CHAIN (candidates))
|| (templates && candidates))
{
cp_error_at ("ambiguous template specialization `%D' for `%+D'",
template_id, decl);
chainon (candidates, templates);
print_candidates (candidates);
return error_mark_node;
}
/* We have one, and exactly one, match. */
if (candidates)
{
/* It was a specialization of an ordinary member function in a
template class. */
*targs_out = copy_node (DECL_TI_ARGS (TREE_VALUE (candidates)));
return DECL_TI_TEMPLATE (TREE_VALUE (candidates));
}
/* It was a specialization of a template. */
targs = DECL_TI_ARGS (DECL_TEMPLATE_RESULT (TREE_VALUE (templates)));
if (TMPL_ARGS_HAVE_MULTIPLE_LEVELS (targs))
{
*targs_out = copy_node (targs);
SET_TMPL_ARGS_LEVEL (*targs_out,
TMPL_ARGS_DEPTH (*targs_out),
TREE_PURPOSE (templates));
}
else
*targs_out = TREE_PURPOSE (templates);
return TREE_VALUE (templates);
}
/* Returns a chain of parameter types, exactly like the SPEC_TYPES,
but with the default argument values filled in from those in the
TMPL_TYPES. */
static tree
copy_default_args_to_explicit_spec_1 (tree spec_types,
tree tmpl_types)
{
tree new_spec_types;
if (!spec_types)
return NULL_TREE;
if (spec_types == void_list_node)
return void_list_node;
/* Substitute into the rest of the list. */
new_spec_types =
copy_default_args_to_explicit_spec_1 (TREE_CHAIN (spec_types),
TREE_CHAIN (tmpl_types));
/* Add the default argument for this parameter. */
return hash_tree_cons (TREE_PURPOSE (tmpl_types),
TREE_VALUE (spec_types),
new_spec_types);
}
/* DECL is an explicit specialization. Replicate default arguments
from the template it specializes. (That way, code like:
template <class T> void f(T = 3);
template <> void f(double);
void g () { f (); }
works, as required.) An alternative approach would be to look up
the correct default arguments at the call-site, but this approach
is consistent with how implicit instantiations are handled. */
static void
copy_default_args_to_explicit_spec (tree decl)
{
tree tmpl;
tree spec_types;
tree tmpl_types;
tree new_spec_types;
tree old_type;
tree new_type;
tree t;
tree object_type = NULL_TREE;
tree in_charge = NULL_TREE;
tree vtt = NULL_TREE;
/* See if there's anything we need to do. */
tmpl = DECL_TI_TEMPLATE (decl);
tmpl_types = TYPE_ARG_TYPES (TREE_TYPE (DECL_TEMPLATE_RESULT (tmpl)));
for (t = tmpl_types; t; t = TREE_CHAIN (t))
if (TREE_PURPOSE (t))
break;
if (!t)
return;
old_type = TREE_TYPE (decl);
spec_types = TYPE_ARG_TYPES (old_type);
if (DECL_NONSTATIC_MEMBER_FUNCTION_P (decl))
{
/* Remove the this pointer, but remember the object's type for
CV quals. */
object_type = TREE_TYPE (TREE_VALUE (spec_types));
spec_types = TREE_CHAIN (spec_types);
tmpl_types = TREE_CHAIN (tmpl_types);
if (DECL_HAS_IN_CHARGE_PARM_P (decl))
{
/* DECL may contain more parameters than TMPL due to the extra
in-charge parameter in constructors and destructors. */
in_charge = spec_types;
spec_types = TREE_CHAIN (spec_types);
}
if (DECL_HAS_VTT_PARM_P (decl))
{
vtt = spec_types;
spec_types = TREE_CHAIN (spec_types);
}
}
/* Compute the merged default arguments. */
new_spec_types =
copy_default_args_to_explicit_spec_1 (spec_types, tmpl_types);
/* Compute the new FUNCTION_TYPE. */
if (object_type)
{
if (vtt)
new_spec_types = hash_tree_cons (TREE_PURPOSE (vtt),
TREE_VALUE (vtt),
new_spec_types);
if (in_charge)
/* Put the in-charge parameter back. */
new_spec_types = hash_tree_cons (TREE_PURPOSE (in_charge),
TREE_VALUE (in_charge),
new_spec_types);
new_type = build_method_type_directly (object_type,
TREE_TYPE (old_type),
new_spec_types);
}
else
new_type = build_function_type (TREE_TYPE (old_type),
new_spec_types);
new_type = cp_build_type_attribute_variant (new_type,
TYPE_ATTRIBUTES (old_type));
new_type = build_exception_variant (new_type,
TYPE_RAISES_EXCEPTIONS (old_type));
TREE_TYPE (decl) = new_type;
}
/* Check to see if the function just declared, as indicated in
DECLARATOR, and in DECL, is a specialization of a function
template. We may also discover that the declaration is an explicit
instantiation at this point.
Returns DECL, or an equivalent declaration that should be used
instead if all goes well. Issues an error message if something is
amiss. Returns error_mark_node if the error is not easily
recoverable.
FLAGS is a bitmask consisting of the following flags:
2: The function has a definition.
4: The function is a friend.
The TEMPLATE_COUNT is the number of references to qualifying
template classes that appeared in the name of the function. For
example, in
template <class T> struct S { void f(); };
void S<int>::f();
the TEMPLATE_COUNT would be 1. However, explicitly specialized
classes are not counted in the TEMPLATE_COUNT, so that in
template <class T> struct S {};
template <> struct S<int> { void f(); }
template <> void S<int>::f();
the TEMPLATE_COUNT would be 0. (Note that this declaration is
invalid; there should be no template <>.)
If the function is a specialization, it is marked as such via
DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
is set up correctly, and it is added to the list of specializations
for that template. */
tree
check_explicit_specialization (tree declarator,
tree decl,
int template_count,
int flags)
{
int have_def = flags & 2;
int is_friend = flags & 4;
int specialization = 0;
int explicit_instantiation = 0;
int member_specialization = 0;
tree ctype = DECL_CLASS_CONTEXT (decl);
tree dname = DECL_NAME (decl);
tmpl_spec_kind tsk;
tsk = current_tmpl_spec_kind (template_count);
switch (tsk)
{
case tsk_none:
if (processing_specialization)
{
specialization = 1;
SET_DECL_TEMPLATE_SPECIALIZATION (decl);
}
else if (TREE_CODE (declarator) == TEMPLATE_ID_EXPR)
{
if (is_friend)
/* This could be something like:
template <class T> void f(T);
class S { friend void f<>(int); } */
specialization = 1;
else
{
/* This case handles bogus declarations like template <>
template <class T> void f<int>(); */
error ("template-id `%D' in declaration of primary template",
declarator);
return decl;
}
}
break;
case tsk_invalid_member_spec:
/* The error has already been reported in
check_specialization_scope. */
return error_mark_node;
case tsk_invalid_expl_inst:
error ("template parameter list used in explicit instantiation");
/* Fall through. */
case tsk_expl_inst:
if (have_def)
error ("definition provided for explicit instantiation");
explicit_instantiation = 1;
break;
case tsk_excessive_parms:
error ("too many template parameter lists in declaration of `%D'",
decl);
return error_mark_node;
/* Fall through. */
case tsk_expl_spec:
SET_DECL_TEMPLATE_SPECIALIZATION (decl);
if (ctype)
member_specialization = 1;
else
specialization = 1;
break;
case tsk_insufficient_parms:
if (template_header_count)
{
error("too few template parameter lists in declaration of `%D'",
decl);
return decl;
}
else if (ctype != NULL_TREE
&& !TYPE_BEING_DEFINED (ctype)
&& CLASSTYPE_TEMPLATE_INSTANTIATION (ctype)
&& !is_friend)
{
/* For backwards compatibility, we accept:
template <class T> struct S { void f(); };
void S<int>::f() {} // Missing template <>
That used to be valid C++. */
if (pedantic)
pedwarn
("explicit specialization not preceded by `template <>'");
specialization = 1;
SET_DECL_TEMPLATE_SPECIALIZATION (decl);
}
break;
case tsk_template:
if (TREE_CODE (declarator) == TEMPLATE_ID_EXPR)
{
/* This case handles bogus declarations like template <>
template <class T> void f<int>(); */
if (uses_template_parms (declarator))
error ("partial specialization `%D' of function template",
declarator);
else
error ("template-id `%D' in declaration of primary template",
declarator);
return decl;
}
if (ctype && CLASSTYPE_TEMPLATE_INSTANTIATION (ctype))
/* This is a specialization of a member template, without
specialization the containing class. Something like:
template <class T> struct S {
template <class U> void f (U);
};
template <> template <class U> void S<int>::f(U) {}
That's a specialization -- but of the entire template. */
specialization = 1;
break;
default:
abort ();
}
if (specialization || member_specialization)
{
tree t = TYPE_ARG_TYPES (TREE_TYPE (decl));
for (; t; t = TREE_CHAIN (t))
if (TREE_PURPOSE (t))
{
pedwarn
("default argument specified in explicit specialization");
break;
}
if (current_lang_name == lang_name_c)
error ("template specialization with C linkage");
}
if (specialization || member_specialization || explicit_instantiation)
{
tree tmpl = NULL_TREE;
tree targs = NULL_TREE;
/* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
if (TREE_CODE (declarator) != TEMPLATE_ID_EXPR)
{
tree fns;
my_friendly_assert (TREE_CODE (declarator) == IDENTIFIER_NODE, 0);
if (ctype)
fns = dname;
else
{
/* If there is no class context, the explicit instantiation
must be at namespace scope. */
my_friendly_assert (DECL_NAMESPACE_SCOPE_P (decl), 20030625);
/* Find the namespace binding, using the declaration
context. */
fns = namespace_binding (dname, CP_DECL_CONTEXT (decl));
}
declarator = lookup_template_function (fns, NULL_TREE);
}
if (declarator == error_mark_node)
return error_mark_node;
if (ctype != NULL_TREE && TYPE_BEING_DEFINED (ctype))
{
if (!explicit_instantiation)
/* A specialization in class scope. This is invalid,
but the error will already have been flagged by
check_specialization_scope. */
return error_mark_node;
else
{
/* It's not valid to write an explicit instantiation in
class scope, e.g.:
class C { template void f(); }
This case is caught by the parser. However, on
something like:
template class C { void f(); };
(which is invalid) we can get here. The error will be
issued later. */
;
}
return decl;
}
else if (ctype != NULL_TREE
&& (TREE_CODE (TREE_OPERAND (declarator, 0)) ==
IDENTIFIER_NODE))
{
/* Find the list of functions in ctype that have the same
name as the declared function. */
tree name = TREE_OPERAND (declarator, 0);
tree fns = NULL_TREE;
int idx;
if (constructor_name_p (name, ctype))
{
int is_constructor = DECL_CONSTRUCTOR_P (decl);
if (is_constructor ? !TYPE_HAS_CONSTRUCTOR (ctype)
: !TYPE_HAS_DESTRUCTOR (ctype))
{
/* From [temp.expl.spec]:
If such an explicit specialization for the member
of a class template names an implicitly-declared
special member function (clause _special_), the
program is ill-formed.
Similar language is found in [temp.explicit]. */
error ("specialization of implicitly-declared special member function");
return error_mark_node;
}
name = is_constructor ? ctor_identifier : dtor_identifier;
}
if (!DECL_CONV_FN_P (decl))
{
idx = lookup_fnfields_1 (ctype, name);
if (idx >= 0)
fns = TREE_VEC_ELT (CLASSTYPE_METHOD_VEC (ctype), idx);
}
else
{
tree methods;
/* For a type-conversion operator, we cannot do a
name-based lookup. We might be looking for `operator
int' which will be a specialization of `operator T'.
So, we find *all* the conversion operators, and then
select from them. */
fns = NULL_TREE;
methods = CLASSTYPE_METHOD_VEC (ctype);
if (methods)
for (idx = CLASSTYPE_FIRST_CONVERSION_SLOT;
idx < TREE_VEC_LENGTH (methods); ++idx)
{
tree ovl = TREE_VEC_ELT (methods, idx);
if (!ovl || !DECL_CONV_FN_P (OVL_CURRENT (ovl)))
/* There are no more conversion functions. */
break;
/* Glue all these conversion functions together
with those we already have. */
for (; ovl; ovl = OVL_NEXT (ovl))
fns = ovl_cons (OVL_CURRENT (ovl), fns);
}
}
if (fns == NULL_TREE)
{
error ("no member function `%D' declared in `%T'",
name, ctype);
return error_mark_node;
}
else
TREE_OPERAND (declarator, 0) = fns;
}
/* Figure out what exactly is being specialized at this point.
Note that for an explicit instantiation, even one for a
member function, we cannot tell apriori whether the
instantiation is for a member template, or just a member
function of a template class. Even if a member template is
being instantiated, the member template arguments may be
elided if they can be deduced from the rest of the
declaration. */
tmpl = determine_specialization (declarator, decl,
&targs,
member_specialization);
if (!tmpl || tmpl == error_mark_node)
/* We couldn't figure out what this declaration was
specializing. */
return error_mark_node;
else
{
tree gen_tmpl = most_general_template (tmpl);
if (explicit_instantiation)
{
/* We don't set DECL_EXPLICIT_INSTANTIATION here; that
is done by do_decl_instantiation later. */
int arg_depth = TMPL_ARGS_DEPTH (targs);
int parm_depth = TMPL_PARMS_DEPTH (DECL_TEMPLATE_PARMS (tmpl));
if (arg_depth > parm_depth)
{
/* If TMPL is not the most general template (for
example, if TMPL is a friend template that is
injected into namespace scope), then there will
be too many levels of TARGS. Remove some of them
here. */
int i;
tree new_targs;
new_targs = make_tree_vec (parm_depth);
for (i = arg_depth - parm_depth; i < arg_depth; ++i)
TREE_VEC_ELT (new_targs, i - (arg_depth - parm_depth))
= TREE_VEC_ELT (targs, i);
targs = new_targs;
}
return instantiate_template (tmpl, targs, tf_error);
}
/* If we thought that the DECL was a member function, but it
turns out to be specializing a static member function,
make DECL a static member function as well. */
if (DECL_STATIC_FUNCTION_P (tmpl)
&& DECL_NONSTATIC_MEMBER_FUNCTION_P (decl))
revert_static_member_fn (decl);
/* If this is a specialization of a member template of a
template class. In we want to return the TEMPLATE_DECL,
not the specialization of it. */
if (tsk == tsk_template)
{
SET_DECL_TEMPLATE_SPECIALIZATION (tmpl);
DECL_INITIAL (DECL_TEMPLATE_RESULT (tmpl)) = NULL_TREE;
if (have_def)
{
DECL_SOURCE_LOCATION (tmpl) = DECL_SOURCE_LOCATION (decl);
DECL_SOURCE_LOCATION (DECL_TEMPLATE_RESULT (tmpl))
= DECL_SOURCE_LOCATION (decl);
}
return tmpl;
}
/* Set up the DECL_TEMPLATE_INFO for DECL. */
DECL_TEMPLATE_INFO (decl) = tree_cons (tmpl, targs, NULL_TREE);
/* Inherit default function arguments from the template
DECL is specializing. */
copy_default_args_to_explicit_spec (decl);
/* This specialization has the same protection as the
template it specializes. */
TREE_PRIVATE (decl) = TREE_PRIVATE (gen_tmpl);
TREE_PROTECTED (decl) = TREE_PROTECTED (gen_tmpl);
if (is_friend && !have_def)
/* This is not really a declaration of a specialization.
It's just the name of an instantiation. But, it's not
a request for an instantiation, either. */
SET_DECL_IMPLICIT_INSTANTIATION (decl);
else if (DECL_CONSTRUCTOR_P (decl) || DECL_DESTRUCTOR_P (decl))
/* This is indeed a specialization. In case of constructors
and destructors, we need in-charge and not-in-charge
versions in V3 ABI. */
clone_function_decl (decl, /*update_method_vec_p=*/0);
/* Register this specialization so that we can find it
again. */
decl = register_specialization (decl, gen_tmpl, targs);
}
}
return decl;
}
/* TYPE is being declared. Verify that the use of template headers
and such is reasonable. Issue error messages if not. */
void
maybe_check_template_type (tree type)
{
if (template_header_count)
{
/* We are in the scope of some `template <...>' header. */
int context_depth
= template_class_depth_real (TYPE_CONTEXT (type),
/*count_specializations=*/1);
if (template_header_count <= context_depth)
/* This is OK; the template headers are for the context. We
are actually too lenient here; like
check_explicit_specialization we should consider the number
of template types included in the actual declaration. For
example,
template <class T> struct S {
template <class U> template <class V>
struct I {};
};
is invalid, but:
template <class T> struct S {
template <class U> struct I;
};
template <class T> template <class U.
struct S<T>::I {};
is not. */
;
else if (template_header_count > context_depth + 1)
/* There are two many template parameter lists. */
error ("too many template parameter lists in declaration of `%T'", type);
}
}
/* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
parameters. These are represented in the same format used for
DECL_TEMPLATE_PARMS. */
int comp_template_parms (tree parms1, tree parms2)
{
tree p1;
tree p2;
if (parms1 == parms2)
return 1;
for (p1 = parms1, p2 = parms2;
p1 != NULL_TREE && p2 != NULL_TREE;
p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2))
{
tree t1 = TREE_VALUE (p1);
tree t2 = TREE_VALUE (p2);
int i;
my_friendly_assert (TREE_CODE (t1) == TREE_VEC, 0);
my_friendly_assert (TREE_CODE (t2) == TREE_VEC, 0);
if (TREE_VEC_LENGTH (t1) != TREE_VEC_LENGTH (t2))
return 0;
for (i = 0; i < TREE_VEC_LENGTH (t2); ++i)
{
tree parm1 = TREE_VALUE (TREE_VEC_ELT (t1, i));
tree parm2 = TREE_VALUE (TREE_VEC_ELT (t2, i));
if (TREE_CODE (parm1) != TREE_CODE (parm2))
return 0;
if (TREE_CODE (parm1) == TEMPLATE_TYPE_PARM)
continue;
else if (!same_type_p (TREE_TYPE (parm1), TREE_TYPE (parm2)))
return 0;
}
}
if ((p1 != NULL_TREE) != (p2 != NULL_TREE))
/* One set of parameters has more parameters lists than the
other. */
return 0;
return 1;
}
/* Complain if DECL shadows a template parameter.
[temp.local]: A template-parameter shall not be redeclared within its
scope (including nested scopes). */
void
check_template_shadow (tree decl)
{
tree olddecl;
/* If we're not in a template, we can't possibly shadow a template
parameter. */
if (!current_template_parms)
return;
/* Figure out what we're shadowing. */
if (TREE_CODE (decl) == OVERLOAD)
decl = OVL_CURRENT (decl);
olddecl = IDENTIFIER_VALUE (DECL_NAME (decl));
/* If there's no previous binding for this name, we're not shadowing
anything, let alone a template parameter. */
if (!olddecl)
return;
/* If we're not shadowing a template parameter, we're done. Note
that OLDDECL might be an OVERLOAD (or perhaps even an
ERROR_MARK), so we can't just blithely assume it to be a _DECL
node. */
if (!DECL_P (olddecl) || !DECL_TEMPLATE_PARM_P (olddecl))
return;
/* We check for decl != olddecl to avoid bogus errors for using a
name inside a class. We check TPFI to avoid duplicate errors for
inline member templates. */
if (decl == olddecl
|| TEMPLATE_PARMS_FOR_INLINE (current_template_parms))
return;
cp_error_at ("declaration of `%#D'", decl);
cp_error_at (" shadows template parm `%#D'", olddecl);
}
/* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
ORIG_LEVEL, DECL, and TYPE. */
static tree
build_template_parm_index (int index,
int level,
int orig_level,
tree decl,
tree type)
{
tree t = make_node (TEMPLATE_PARM_INDEX);
TEMPLATE_PARM_IDX (t) = index;
TEMPLATE_PARM_LEVEL (t) = level;
TEMPLATE_PARM_ORIG_LEVEL (t) = orig_level;
TEMPLATE_PARM_DECL (t) = decl;
TREE_TYPE (t) = type;
TREE_CONSTANT (t) = TREE_CONSTANT (decl);
TREE_READONLY (t) = TREE_READONLY (decl);
return t;
}
/* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
new one is created. */
static tree
reduce_template_parm_level (tree index, tree type, int levels)
{
if (TEMPLATE_PARM_DESCENDANTS (index) == NULL_TREE
|| (TEMPLATE_PARM_LEVEL (TEMPLATE_PARM_DESCENDANTS (index))
!= TEMPLATE_PARM_LEVEL (index) - levels))
{
tree orig_decl = TEMPLATE_PARM_DECL (index);
tree decl, t;
decl = build_decl (TREE_CODE (orig_decl), DECL_NAME (orig_decl), type);
TREE_CONSTANT (decl) = TREE_CONSTANT (orig_decl);
TREE_READONLY (decl) = TREE_READONLY (orig_decl);
DECL_ARTIFICIAL (decl) = 1;
SET_DECL_TEMPLATE_PARM_P (decl);
t = build_template_parm_index (TEMPLATE_PARM_IDX (index),
TEMPLATE_PARM_LEVEL (index) - levels,
TEMPLATE_PARM_ORIG_LEVEL (index),
decl, type);
TEMPLATE_PARM_DESCENDANTS (index) = t;
/* Template template parameters need this. */
DECL_TEMPLATE_PARMS (decl)
= DECL_TEMPLATE_PARMS (TEMPLATE_PARM_DECL (index));
}
return TEMPLATE_PARM_DESCENDANTS (index);
}
/* Process information from new template parameter NEXT and append it to the
LIST being built. */
tree
process_template_parm (tree list, tree next)
{
tree parm;
tree decl = 0;
tree defval;
int is_type, idx;
parm = next;
my_friendly_assert (TREE_CODE (parm) == TREE_LIST, 259);
defval = TREE_PURPOSE (parm);
parm = TREE_VALUE (parm);
is_type = TREE_PURPOSE (parm) == class_type_node;
if (list)
{
tree p = TREE_VALUE (tree_last (list));
if (TREE_CODE (p) == TYPE_DECL || TREE_CODE (p) == TEMPLATE_DECL)
idx = TEMPLATE_TYPE_IDX (TREE_TYPE (p));
else
idx = TEMPLATE_PARM_IDX (DECL_INITIAL (p));
++idx;
}
else
idx = 0;
if (!is_type)
{
my_friendly_assert (TREE_CODE (TREE_PURPOSE (parm)) == TREE_LIST, 260);
/* is a const-param */
parm = grokdeclarator (TREE_VALUE (parm), TREE_PURPOSE (parm),
PARM, 0, NULL);
SET_DECL_TEMPLATE_PARM_P (parm);
/* [temp.param]
The top-level cv-qualifiers on the template-parameter are
ignored when determining its type. */
TREE_TYPE (parm) = TYPE_MAIN_VARIANT (TREE_TYPE (parm));
/* A template parameter is not modifiable. */
TREE_READONLY (parm) = TREE_CONSTANT (parm) = 1;
if (invalid_nontype_parm_type_p (TREE_TYPE (parm), 1))
TREE_TYPE (parm) = void_type_node;
decl = build_decl (CONST_DECL, DECL_NAME (parm), TREE_TYPE (parm));
TREE_CONSTANT (decl) = TREE_READONLY (decl) = 1;
DECL_INITIAL (parm) = DECL_INITIAL (decl)
= build_template_parm_index (idx, processing_template_decl,
processing_template_decl,
decl, TREE_TYPE (parm));
}
else
{
tree t;
parm = TREE_VALUE (parm);
if (parm && TREE_CODE (parm) == TEMPLATE_DECL)
{
t = make_aggr_type (TEMPLATE_TEMPLATE_PARM);
/* This is for distinguishing between real templates and template
template parameters */
TREE_TYPE (parm) = t;
TREE_TYPE (DECL_TEMPLATE_RESULT (parm)) = t;
decl = parm;
}
else
{
t = make_aggr_type (TEMPLATE_TYPE_PARM);
/* parm is either IDENTIFIER_NODE or NULL_TREE. */
decl = build_decl (TYPE_DECL, parm, t);
}
TYPE_NAME (t) = decl;
TYPE_STUB_DECL (t) = decl;
parm = decl;
TEMPLATE_TYPE_PARM_INDEX (t)
= build_template_parm_index (idx, processing_template_decl,
processing_template_decl,
decl, TREE_TYPE (parm));
}
DECL_ARTIFICIAL (decl) = 1;
SET_DECL_TEMPLATE_PARM_P (decl);
pushdecl (decl);
parm = build_tree_list (defval, parm);
return chainon (list, parm);
}
/* The end of a template parameter list has been reached. Process the
tree list into a parameter vector, converting each parameter into a more
useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
as PARM_DECLs. */
tree
end_template_parm_list (tree parms)
{
int nparms;
tree parm, next;
tree saved_parmlist = make_tree_vec (list_length (parms));
current_template_parms
= tree_cons (size_int (processing_template_decl),
saved_parmlist, current_template_parms);
for (parm = parms, nparms = 0; parm; parm = next, nparms++)
{
next = TREE_CHAIN (parm);
TREE_VEC_ELT (saved_parmlist, nparms) = parm;
TREE_CHAIN (parm) = NULL_TREE;
}
--processing_template_parmlist;
return saved_parmlist;
}
/* end_template_decl is called after a template declaration is seen. */
void
end_template_decl (void)
{
reset_specialization ();
if (! processing_template_decl)
return;
/* This matches the pushlevel in begin_template_parm_list. */
finish_scope ();
--processing_template_decl;
current_template_parms = TREE_CHAIN (current_template_parms);
}
/* Given a template argument vector containing the template PARMS.
The innermost PARMS are given first. */
tree
current_template_args (void)
{
tree header;
tree args = NULL_TREE;
int length = TMPL_PARMS_DEPTH (current_template_parms);
int l = length;
/* If there is only one level of template parameters, we do not
create a TREE_VEC of TREE_VECs. Instead, we return a single
TREE_VEC containing the arguments. */
if (length > 1)
args = make_tree_vec (length);
for (header = current_template_parms; header; header = TREE_CHAIN (header))
{
tree a = copy_node (TREE_VALUE (header));
int i;
TREE_TYPE (a) = NULL_TREE;
for (i = TREE_VEC_LENGTH (a) - 1; i >= 0; --i)
{
tree t = TREE_VEC_ELT (a, i);
/* T will be a list if we are called from within a
begin/end_template_parm_list pair, but a vector directly
if within a begin/end_member_template_processing pair. */
if (TREE_CODE (t) == TREE_LIST)
{
t = TREE_VALUE (t);
if (TREE_CODE (t) == TYPE_DECL
|| TREE_CODE (t) == TEMPLATE_DECL)
t = TREE_TYPE (t);
else
t = DECL_INITIAL (t);
TREE_VEC_ELT (a, i) = t;
}
}
if (length > 1)
TREE_VEC_ELT (args, --l) = a;
else
args = a;
}
return args;
}
/* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
template PARMS. Used by push_template_decl below. */
static tree
build_template_decl (tree decl, tree parms)
{
tree tmpl = build_lang_decl (TEMPLATE_DECL, DECL_NAME (decl), NULL_TREE);
DECL_TEMPLATE_PARMS (tmpl) = parms;
DECL_CONTEXT (tmpl) = DECL_CONTEXT (decl);
if (DECL_LANG_SPECIFIC (decl))
{
DECL_STATIC_FUNCTION_P (tmpl) = DECL_STATIC_FUNCTION_P (decl);
DECL_CONSTRUCTOR_P (tmpl) = DECL_CONSTRUCTOR_P (decl);
DECL_DESTRUCTOR_P (tmpl) = DECL_DESTRUCTOR_P (decl);
DECL_NONCONVERTING_P (tmpl) = DECL_NONCONVERTING_P (decl);
DECL_ASSIGNMENT_OPERATOR_P (tmpl) = DECL_ASSIGNMENT_OPERATOR_P (decl);
if (DECL_OVERLOADED_OPERATOR_P (decl))
SET_OVERLOADED_OPERATOR_CODE (tmpl,
DECL_OVERLOADED_OPERATOR_P (decl));
}
return tmpl;
}
struct template_parm_data
{
/* The level of the template parameters we are currently
processing. */
int level;
/* The index of the specialization argument we are currently
processing. */
int current_arg;
/* An array whose size is the number of template parameters. The
elements are nonzero if the parameter has been used in any one
of the arguments processed so far. */
int* parms;
/* An array whose size is the number of template arguments. The
elements are nonzero if the argument makes use of template
parameters of this level. */
int* arg_uses_template_parms;
};
/* Subroutine of push_template_decl used to see if each template
parameter in a partial specialization is used in the explicit
argument list. If T is of the LEVEL given in DATA (which is
treated as a template_parm_data*), then DATA->PARMS is marked
appropriately. */
static int
mark_template_parm (tree t, void* data)
{
int level;
int idx;
struct template_parm_data* tpd = (struct template_parm_data*) data;
if (TREE_CODE (t) == TEMPLATE_PARM_INDEX)
{
level = TEMPLATE_PARM_LEVEL (t);
idx = TEMPLATE_PARM_IDX (t);
}
else
{
level = TEMPLATE_TYPE_LEVEL (t);
idx = TEMPLATE_TYPE_IDX (t);
}
if (level == tpd->level)
{
tpd->parms[idx] = 1;
tpd->arg_uses_template_parms[tpd->current_arg] = 1;
}
/* Return zero so that for_each_template_parm will continue the
traversal of the tree; we want to mark *every* template parm. */
return 0;
}
/* Process the partial specialization DECL. */
static tree
process_partial_specialization (tree decl)
{
tree type = TREE_TYPE (decl);
tree maintmpl = CLASSTYPE_TI_TEMPLATE (type);
tree specargs = CLASSTYPE_TI_ARGS (type);
tree inner_args = INNERMOST_TEMPLATE_ARGS (specargs);
tree inner_parms = INNERMOST_TEMPLATE_PARMS (current_template_parms);
tree main_inner_parms = DECL_INNERMOST_TEMPLATE_PARMS (maintmpl);
int nargs = TREE_VEC_LENGTH (inner_args);
int ntparms = TREE_VEC_LENGTH (inner_parms);
int i;
int did_error_intro = 0;
struct template_parm_data tpd;
struct template_parm_data tpd2;
/* We check that each of the template parameters given in the
partial specialization is used in the argument list to the
specialization. For example:
template <class T> struct S;
template <class T> struct S<T*>;
The second declaration is OK because `T*' uses the template
parameter T, whereas
template <class T> struct S<int>;
is no good. Even trickier is:
template <class T>
struct S1
{
template <class U>
struct S2;
template <class U>
struct S2<T>;
};
The S2<T> declaration is actually invalid; it is a
full-specialization. Of course,
template <class U>
struct S2<T (*)(U)>;
or some such would have been OK. */
tpd.level = TMPL_PARMS_DEPTH (current_template_parms);
tpd.parms = alloca (sizeof (int) * ntparms);
memset (tpd.parms, 0, sizeof (int) * ntparms);
tpd.arg_uses_template_parms = alloca (sizeof (int) * nargs);
memset (tpd.arg_uses_template_parms, 0, sizeof (int) * nargs);
for (i = 0; i < nargs; ++i)
{
tpd.current_arg = i;
for_each_template_parm (TREE_VEC_ELT (inner_args, i),
&mark_template_parm,
&tpd,
NULL);
}
for (i = 0; i < ntparms; ++i)
if (tpd.parms[i] == 0)
{
/* One of the template parms was not used in the
specialization. */
if (!did_error_intro)
{
error ("template parameters not used in partial specialization:");
did_error_intro = 1;
}
error (" `%D'",
TREE_VALUE (TREE_VEC_ELT (inner_parms, i)));
}
/* [temp.class.spec]
The argument list of the specialization shall not be identical to
the implicit argument list of the primary template. */
if (comp_template_args
(inner_args,
INNERMOST_TEMPLATE_ARGS (CLASSTYPE_TI_ARGS (TREE_TYPE
(maintmpl)))))
error ("partial specialization `%T' does not specialize any template arguments", type);
/* [temp.class.spec]
A partially specialized non-type argument expression shall not
involve template parameters of the partial specialization except
when the argument expression is a simple identifier.
The type of a template parameter corresponding to a specialized
non-type argument shall not be dependent on a parameter of the
specialization. */
my_friendly_assert (nargs == DECL_NTPARMS (maintmpl), 0);
tpd2.parms = 0;
for (i = 0; i < nargs; ++i)
{
tree arg = TREE_VEC_ELT (inner_args, i);
if (/* These first two lines are the `non-type' bit. */
!TYPE_P (arg)
&& TREE_CODE (arg) != TEMPLATE_DECL
/* This next line is the `argument expression is not just a
simple identifier' condition and also the `specialized
non-type argument' bit. */
&& TREE_CODE (arg) != TEMPLATE_PARM_INDEX)
{
if (tpd.arg_uses_template_parms[i])
error ("template argument `%E' involves template parameter(s)", arg);
else
{
/* Look at the corresponding template parameter,
marking which template parameters its type depends
upon. */
tree type =
TREE_TYPE (TREE_VALUE (TREE_VEC_ELT (main_inner_parms,
i)));
if (!tpd2.parms)
{
/* We haven't yet initialized TPD2. Do so now. */
tpd2.arg_uses_template_parms
= alloca (sizeof (int) * nargs);
/* The number of parameters here is the number in the
main template, which, as checked in the assertion
above, is NARGS. */
tpd2.parms = alloca (sizeof (int) * nargs);
tpd2.level =
TMPL_PARMS_DEPTH (DECL_TEMPLATE_PARMS (maintmpl));
}
/* Mark the template parameters. But this time, we're
looking for the template parameters of the main
template, not in the specialization. */
tpd2.current_arg = i;
tpd2.arg_uses_template_parms[i] = 0;
memset (tpd2.parms, 0, sizeof (int) * nargs);
for_each_template_parm (type,
&mark_template_parm,
&tpd2,
NULL);
if (tpd2.arg_uses_template_parms [i])
{
/* The type depended on some template parameters.
If they are fully specialized in the
specialization, that's OK. */
int j;
for (j = 0; j < nargs; ++j)
if (tpd2.parms[j] != 0
&& tpd.arg_uses_template_parms [j])
{
error ("type `%T' of template argument `%E' depends on template parameter(s)",
type,
arg);
break;
}
}
}
}
}
if (retrieve_specialization (maintmpl, specargs))
/* We've already got this specialization. */
return decl;
DECL_TEMPLATE_SPECIALIZATIONS (maintmpl)
= tree_cons (inner_args, inner_parms,
DECL_TEMPLATE_SPECIALIZATIONS (maintmpl));
TREE_TYPE (DECL_TEMPLATE_SPECIALIZATIONS (maintmpl)) = type;
return decl;
}
/* Check that a template declaration's use of default arguments is not
invalid. Here, PARMS are the template parameters. IS_PRIMARY is
nonzero if DECL is the thing declared by a primary template.
IS_PARTIAL is nonzero if DECL is a partial specialization. */
static void
check_default_tmpl_args (tree decl, tree parms, int is_primary, int is_partial)
{
const char *msg;
int last_level_to_check;
tree parm_level;
/* [temp.param]
A default template-argument shall not be specified in a
function template declaration or a function template definition, nor
in the template-parameter-list of the definition of a member of a
class template. */
if (TREE_CODE (CP_DECL_CONTEXT (decl)) == FUNCTION_DECL)
/* You can't have a function template declaration in a local
scope, nor you can you define a member of a class template in a
local scope. */
return;
if (current_class_type
&& !TYPE_BEING_DEFINED (current_class_type)
&& DECL_LANG_SPECIFIC (decl)
/* If this is either a friend defined in the scope of the class
or a member function. */
&& (DECL_FUNCTION_MEMBER_P (decl)
? same_type_p (DECL_CONTEXT (decl), current_class_type)
: DECL_FRIEND_CONTEXT (decl)
? same_type_p (DECL_FRIEND_CONTEXT (decl), current_class_type)
: false)
/* And, if it was a member function, it really was defined in
the scope of the class. */
&& (!DECL_FUNCTION_MEMBER_P (decl)
|| DECL_INITIALIZED_IN_CLASS_P (decl)))
/* We already checked these parameters when the template was
declared, so there's no need to do it again now. This function
was defined in class scope, but we're processing it's body now
that the class is complete. */
return;
/* [temp.param]
If a template-parameter has a default template-argument, all
subsequent template-parameters shall have a default
template-argument supplied. */
for (parm_level = parms; parm_level; parm_level = TREE_CHAIN (parm_level))
{
tree inner_parms = TREE_VALUE (parm_level);
int ntparms = TREE_VEC_LENGTH (inner_parms);
int seen_def_arg_p = 0;
int i;
for (i = 0; i < ntparms; ++i)
{
tree parm = TREE_VEC_ELT (inner_parms, i);
if (TREE_PURPOSE (parm))
seen_def_arg_p = 1;
else if (seen_def_arg_p)
{
error ("no default argument for `%D'", TREE_VALUE (parm));
/* For better subsequent error-recovery, we indicate that
there should have been a default argument. */
TREE_PURPOSE (parm) = error_mark_node;
}
}
}
if (TREE_CODE (decl) != TYPE_DECL || is_partial || !is_primary)
/* For an ordinary class template, default template arguments are
allowed at the innermost level, e.g.:
template <class T = int>
struct S {};
but, in a partial specialization, they're not allowed even
there, as we have in [temp.class.spec]:
The template parameter list of a specialization shall not
contain default template argument values.
So, for a partial specialization, or for a function template,
we look at all of them. */
;
else
/* But, for a primary class template that is not a partial
specialization we look at all template parameters except the
innermost ones. */
parms = TREE_CHAIN (parms);
/* Figure out what error message to issue. */
if (TREE_CODE (decl) == FUNCTION_DECL)
msg = "default template arguments may not be used in function templates";
else if (is_partial)
msg = "default template arguments may not be used in partial specializations";
else
msg = "default argument for template parameter for class enclosing `%D'";
if (current_class_type && TYPE_BEING_DEFINED (current_class_type))
/* If we're inside a class definition, there's no need to
examine the parameters to the class itself. On the one
hand, they will be checked when the class is defined, and,
on the other, default arguments are valid in things like:
template <class T = double>
struct S { template <class U> void f(U); };
Here the default argument for `S' has no bearing on the
declaration of `f'. */
last_level_to_check = template_class_depth (current_class_type) + 1;
else
/* Check everything. */
last_level_to_check = 0;
for (parm_level = parms;
parm_level && TMPL_PARMS_DEPTH (parm_level) >= last_level_to_check;
parm_level = TREE_CHAIN (parm_level))
{
tree inner_parms = TREE_VALUE (parm_level);
int i;
int ntparms;
ntparms = TREE_VEC_LENGTH (inner_parms);
for (i = 0; i < ntparms; ++i)
if (TREE_PURPOSE (TREE_VEC_ELT (inner_parms, i)))
{
if (msg)
{
error (msg, decl);
msg = 0;
}
/* Clear out the default argument so that we are not
confused later. */
TREE_PURPOSE (TREE_VEC_ELT (inner_parms, i)) = NULL_TREE;
}
/* At this point, if we're still interested in issuing messages,
they must apply to classes surrounding the object declared. */
if (msg)
msg = "default argument for template parameter for class enclosing `%D'";
}
}
/* Worker for push_template_decl_real, called via
for_each_template_parm. DATA is really an int, indicating the
level of the parameters we are interested in. If T is a template
parameter of that level, return nonzero. */
static int
template_parm_this_level_p (tree t, void* data)
{
int this_level = *(int *)data;
int level;
if (TREE_CODE (t) == TEMPLATE_PARM_INDEX)
level = TEMPLATE_PARM_LEVEL (t);
else
level = TEMPLATE_TYPE_LEVEL (t);
return level == this_level;
}
/* Creates a TEMPLATE_DECL for the indicated DECL using the template
parameters given by current_template_args, or reuses a
previously existing one, if appropriate. Returns the DECL, or an
equivalent one, if it is replaced via a call to duplicate_decls.
If IS_FRIEND is nonzero, DECL is a friend declaration. */
tree
push_template_decl_real (tree decl, int is_friend)
{
tree tmpl;
tree args;
tree info;
tree ctx;
int primary;
int is_partial;
int new_template_p = 0;
/* See if this is a partial specialization. */
is_partial = (DECL_IMPLICIT_TYPEDEF_P (decl)
&& TREE_CODE (TREE_TYPE (decl)) != ENUMERAL_TYPE
&& CLASSTYPE_TEMPLATE_SPECIALIZATION (TREE_TYPE (decl)));
is_friend |= (TREE_CODE (decl) == FUNCTION_DECL && DECL_FRIEND_P (decl));
if (is_friend)
/* For a friend, we want the context of the friend function, not
the type of which it is a friend. */
ctx = DECL_CONTEXT (decl);
else if (CP_DECL_CONTEXT (decl)
&& TREE_CODE (CP_DECL_CONTEXT (decl)) != NAMESPACE_DECL)
/* In the case of a virtual function, we want the class in which
it is defined. */
ctx = CP_DECL_CONTEXT (decl);
else
/* Otherwise, if we're currently defining some class, the DECL
is assumed to be a member of the class. */
ctx = current_scope ();
if (ctx && TREE_CODE (ctx) == NAMESPACE_DECL)
ctx = NULL_TREE;
if (!DECL_CONTEXT (decl))
DECL_CONTEXT (decl) = FROB_CONTEXT (current_namespace);
/* See if this is a primary template. */
primary = template_parm_scope_p ();
if (primary)
{
if (current_lang_name == lang_name_c)
error ("template with C linkage");
else if (TREE_CODE (decl) == TYPE_DECL
&& ANON_AGGRNAME_P (DECL_NAME (decl)))
error ("template class without a name");
else if (TREE_CODE (decl) == FUNCTION_DECL)
{
if (DECL_DESTRUCTOR_P (decl))
{
/* [temp.mem]
A destructor shall not be a member template. */
error ("destructor `%D' declared as member template", decl);
return error_mark_node;
}
if (NEW_DELETE_OPNAME_P (DECL_NAME (decl))
&& (!TYPE_ARG_TYPES (TREE_TYPE (decl))
|| TYPE_ARG_TYPES (TREE_TYPE (decl)) == void_list_node
|| !TREE_CHAIN (TYPE_ARG_TYPES (TREE_TYPE (decl)))
|| (TREE_CHAIN (TYPE_ARG_TYPES ((TREE_TYPE (decl))))
== void_list_node)))
{
/* [basic.stc.dynamic.allocation]
An allocation function can be a function
template. ... Template allocation functions shall
have two or more parameters. */
error ("invalid template declaration of `%D'", decl);
return decl;
}
}
else if ((DECL_IMPLICIT_TYPEDEF_P (decl)
&& CLASS_TYPE_P (TREE_TYPE (decl)))
|| (TREE_CODE (decl) == VAR_DECL && ctx && CLASS_TYPE_P (ctx)))
/* OK */;
else
{
error ("template declaration of `%#D'", decl);
return error_mark_node;
}
}
/* Check to see that the rules regarding the use of default
arguments are not being violated. */
check_default_tmpl_args (decl, current_template_parms,
primary, is_partial);
if (is_partial)
return process_partial_specialization (decl);
args = current_template_args ();
if (!ctx
|| TREE_CODE (ctx) == FUNCTION_DECL
|| (CLASS_TYPE_P (ctx) && TYPE_BEING_DEFINED (ctx))
|| (is_friend && !DECL_TEMPLATE_INFO (decl)))
{
if (DECL_LANG_SPECIFIC (decl)
&& DECL_TEMPLATE_INFO (decl)
&& DECL_TI_TEMPLATE (decl))
tmpl = DECL_TI_TEMPLATE (decl);
/* If DECL is a TYPE_DECL for a class-template, then there won't
be DECL_LANG_SPECIFIC. The information equivalent to
DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
else if (DECL_IMPLICIT_TYPEDEF_P (decl)
&& TYPE_TEMPLATE_INFO (TREE_TYPE (decl))
&& TYPE_TI_TEMPLATE (TREE_TYPE (decl)))
{
/* Since a template declaration already existed for this
class-type, we must be redeclaring it here. Make sure
that the redeclaration is valid. */
redeclare_class_template (TREE_TYPE (decl),
current_template_parms);
/* We don't need to create a new TEMPLATE_DECL; just use the
one we already had. */
tmpl = TYPE_TI_TEMPLATE (TREE_TYPE (decl));
}
else
{
tmpl = build_template_decl (decl, current_template_parms);
new_template_p = 1;
if (DECL_LANG_SPECIFIC (decl)
&& DECL_TEMPLATE_SPECIALIZATION (decl))
{
/* A specialization of a member template of a template
class. */
SET_DECL_TEMPLATE_SPECIALIZATION (tmpl);
DECL_TEMPLATE_INFO (tmpl) = DECL_TEMPLATE_INFO (decl);
DECL_TEMPLATE_INFO (decl) = NULL_TREE;
}
}
}
else
{
tree a, t, current, parms;
int i;
if (TREE_CODE (decl) == TYPE_DECL)
{
if ((IS_AGGR_TYPE_CODE (TREE_CODE (TREE_TYPE (decl)))
|| TREE_CODE (TREE_TYPE (decl)) == ENUMERAL_TYPE)
&& TYPE_TEMPLATE_INFO (TREE_TYPE (decl))
&& TYPE_TI_TEMPLATE (TREE_TYPE (decl)))
tmpl = TYPE_TI_TEMPLATE (TREE_TYPE (decl));
else
{
error ("`%D' does not declare a template type", decl);
return decl;
}
}
else if (!DECL_LANG_SPECIFIC (decl) || !DECL_TEMPLATE_INFO (decl))
{
error ("template definition of non-template `%#D'", decl);
return decl;
}
else
tmpl = DECL_TI_TEMPLATE (decl);
if (DECL_FUNCTION_TEMPLATE_P (tmpl)
&& DECL_TEMPLATE_INFO (decl) && DECL_TI_ARGS (decl)
&& DECL_TEMPLATE_SPECIALIZATION (decl)
&& is_member_template (tmpl))
{
tree new_tmpl;
/* The declaration is a specialization of a member
template, declared outside the class. Therefore, the
innermost template arguments will be NULL, so we
replace them with the arguments determined by the
earlier call to check_explicit_specialization. */
args = DECL_TI_ARGS (decl);
new_tmpl
= build_template_decl (decl, current_template_parms);
DECL_TEMPLATE_RESULT (new_tmpl) = decl;
TREE_TYPE (new_tmpl) = TREE_TYPE (decl);
DECL_TI_TEMPLATE (decl) = new_tmpl;
SET_DECL_TEMPLATE_SPECIALIZATION (new_tmpl);
DECL_TEMPLATE_INFO (new_tmpl)
= tree_cons (tmpl, args, NULL_TREE);
register_specialization (new_tmpl,
most_general_template (tmpl),
args);
return decl;
}
/* Make sure the template headers we got make sense. */
parms = DECL_TEMPLATE_PARMS (tmpl);
i = TMPL_PARMS_DEPTH (parms);
if (TMPL_ARGS_DEPTH (args) != i)
{
error ("expected %d levels of template parms for `%#D', got %d",
i, decl, TMPL_ARGS_DEPTH (args));
}
else
for (current = decl; i > 0; --i, parms = TREE_CHAIN (parms))
{
a = TMPL_ARGS_LEVEL (args, i);
t = INNERMOST_TEMPLATE_PARMS (parms);
if (TREE_VEC_LENGTH (t) != TREE_VEC_LENGTH (a))
{
if (current == decl)
error ("got %d template parameters for `%#D'",
TREE_VEC_LENGTH (a), decl);
else
error ("got %d template parameters for `%#T'",
TREE_VEC_LENGTH (a), current);
error (" but %d required", TREE_VEC_LENGTH (t));
}
/* Perhaps we should also check that the parms are used in the
appropriate qualifying scopes in the declarator? */
if (current == decl)
current = ctx;
else
current = TYPE_CONTEXT (current);
}
}
DECL_TEMPLATE_RESULT (tmpl) = decl;
TREE_TYPE (tmpl) = TREE_TYPE (decl);
/* Push template declarations for global functions and types. Note
that we do not try to push a global template friend declared in a
template class; such a thing may well depend on the template
parameters of the class. */
if (new_template_p && !ctx
&& !(is_friend && template_class_depth (current_class_type) > 0))
tmpl = pushdecl_namespace_level (tmpl);
if (primary)
{
DECL_PRIMARY_TEMPLATE (tmpl) = tmpl;
if (DECL_CONV_FN_P (tmpl))
{
int depth = TMPL_PARMS_DEPTH (DECL_TEMPLATE_PARMS (tmpl));
/* It is a conversion operator. See if the type converted to
depends on innermost template operands. */
if (uses_template_parms_level (TREE_TYPE (TREE_TYPE (tmpl)),
depth))
DECL_TEMPLATE_CONV_FN_P (tmpl) = 1;
}
}
/* The DECL_TI_ARGS of DECL contains full set of arguments refering
back to its most general template. If TMPL is a specialization,
ARGS may only have the innermost set of arguments. Add the missing
argument levels if necessary. */
if (DECL_TEMPLATE_INFO (tmpl))
args = add_outermost_template_args (DECL_TI_ARGS (tmpl), args);
info = tree_cons (tmpl, args, NULL_TREE);
if (DECL_IMPLICIT_TYPEDEF_P (decl))
{
SET_TYPE_TEMPLATE_INFO (TREE_TYPE (tmpl), info);
if ((!ctx || TREE_CODE (ctx) != FUNCTION_DECL)
&& TREE_CODE (TREE_TYPE (decl)) != ENUMERAL_TYPE
/* Don't change the name if we've already set it up. */
&& !IDENTIFIER_TEMPLATE (DECL_NAME (decl)))
DECL_NAME (decl) = classtype_mangled_name (TREE_TYPE (decl));
}
else if (DECL_LANG_SPECIFIC (decl))
DECL_TEMPLATE_INFO (decl) = info;
return DECL_TEMPLATE_RESULT (tmpl);
}
tree
push_template_decl (tree decl)
{
return push_template_decl_real (decl, 0);
}
/* Called when a class template TYPE is redeclared with the indicated
template PARMS, e.g.:
template <class T> struct S;
template <class T> struct S {}; */
void
redeclare_class_template (tree type, tree parms)
{
tree tmpl;
tree tmpl_parms;
int i;
if (!TYPE_TEMPLATE_INFO (type))
{
error ("`%T' is not a template type", type);
return;
}
tmpl = TYPE_TI_TEMPLATE (type);
if (!PRIMARY_TEMPLATE_P (tmpl))
/* The type is nested in some template class. Nothing to worry
about here; there are no new template parameters for the nested
type. */
return;
parms = INNERMOST_TEMPLATE_PARMS (parms);
tmpl_parms = DECL_INNERMOST_TEMPLATE_PARMS (tmpl);
if (TREE_VEC_LENGTH (parms) != TREE_VEC_LENGTH (tmpl_parms))
{
cp_error_at ("previous declaration `%D'", tmpl);
error ("used %d template parameter%s instead of %d",
TREE_VEC_LENGTH (tmpl_parms),
TREE_VEC_LENGTH (tmpl_parms) == 1 ? "" : "s",
TREE_VEC_LENGTH (parms));
return;
}
for (i = 0; i < TREE_VEC_LENGTH (tmpl_parms); ++i)
{
tree tmpl_parm = TREE_VALUE (TREE_VEC_ELT (tmpl_parms, i));
tree parm = TREE_VALUE (TREE_VEC_ELT (parms, i));
tree tmpl_default = TREE_PURPOSE (TREE_VEC_ELT (tmpl_parms, i));
tree parm_default = TREE_PURPOSE (TREE_VEC_ELT (parms, i));
if (TREE_CODE (tmpl_parm) != TREE_CODE (parm))
{
cp_error_at ("template parameter `%#D'", tmpl_parm);
error ("redeclared here as `%#D'", parm);
return;
}
if (tmpl_default != NULL_TREE && parm_default != NULL_TREE)
{
/* We have in [temp.param]:
A template-parameter may not be given default arguments
by two different declarations in the same scope. */
error ("redefinition of default argument for `%#D'", parm);
error ("%J original definition appeared here", tmpl_parm);
return;
}
if (parm_default != NULL_TREE)
/* Update the previous template parameters (which are the ones
that will really count) with the new default value. */
TREE_PURPOSE (TREE_VEC_ELT (tmpl_parms, i)) = parm_default;
else if (tmpl_default != NULL_TREE)
/* Update the new parameters, too; they'll be used as the
parameters for any members. */
TREE_PURPOSE (TREE_VEC_ELT (parms, i)) = tmpl_default;
}
}
/* Simplify EXPR if it is a non-dependent expression. Returns the
(possibly simplified) expression. */
tree
fold_non_dependent_expr (tree expr)
{
/* If we're in a template, but EXPR isn't value dependent, simplify
it. We're supposed to treat:
template <typename T> void f(T[1 + 1]);
template <typename T> void f(T[2]);
as two declarations of the same function, for example. */
if (processing_template_decl
&& !type_dependent_expression_p (expr)
&& !value_dependent_expression_p (expr))
{
HOST_WIDE_INT saved_processing_template_decl;
saved_processing_template_decl = processing_template_decl;
processing_template_decl = 0;
expr = tsubst_copy_and_build (expr,
/*args=*/NULL_TREE,
tf_error,
/*in_decl=*/NULL_TREE,
/*function_p=*/false);
processing_template_decl = saved_processing_template_decl;
}
return expr;
}
/* Attempt to convert the non-type template parameter EXPR to the
indicated TYPE. If the conversion is successful, return the
converted value. If the conversion is unsuccessful, return
NULL_TREE if we issued an error message, or error_mark_node if we
did not. We issue error messages for out-and-out bad template
parameters, but not simply because the conversion failed, since we
might be just trying to do argument deduction. Both TYPE and EXPR
must be non-dependent. */
static tree
convert_nontype_argument (tree type, tree expr)
{
tree expr_type;
/* If we are in a template, EXPR may be non-dependent, but still
have a syntactic, rather than semantic, form. For example, EXPR
might be a SCOPE_REF, rather than the VAR_DECL to which the
SCOPE_REF refers. Preserving the qualifying scope is necessary
so that access checking can be performed when the template is
instantiated -- but here we need the resolved form so that we can
convert the argument. */
expr = fold_non_dependent_expr (expr);
expr_type = TREE_TYPE (expr);
/* A template-argument for a non-type, non-template
template-parameter shall be one of:
--an integral constant-expression of integral or enumeration
type; or
--the name of a non-type template-parameter; or
--the name of an object or function with external linkage,
including function templates and function template-ids but
excluding non-static class members, expressed as id-expression;
or
--the address of an object or function with external linkage,
including function templates and function template-ids but
excluding non-static class members, expressed as & id-expression
where the & is optional if the name refers to a function or
array; or
--a pointer to member expressed as described in _expr.unary.op_. */
/* An integral constant-expression can include const variables or
. enumerators. Simplify things by folding them to their values,
unless we're about to bind the declaration to a reference
parameter. */
if (INTEGRAL_TYPE_P (expr_type) && TREE_CODE (type) != REFERENCE_TYPE)
while (true)
{
tree const_expr = decl_constant_value (expr);
/* In a template, the initializer for a VAR_DECL may not be
marked as TREE_CONSTANT, in which case decl_constant_value
will not return the initializer. Handle that special case
here. */
if (expr == const_expr
&& DECL_INTEGRAL_CONSTANT_VAR_P (expr)
/* DECL_INITIAL can be NULL if we are processing a
variable initialized to an expression involving itself.
We know it is initialized to a constant -- but not what
constant, yet. */
&& DECL_INITIAL (expr))
const_expr = DECL_INITIAL (expr);
if (expr == const_expr)
break;
expr = fold_non_dependent_expr (const_expr);
}
if (is_overloaded_fn (expr))
/* OK for now. We'll check that it has external linkage later.
Check this first since if expr_type is the unknown_type_node
we would otherwise complain below. */
;
else if (TYPE_PTR_TO_MEMBER_P (expr_type))
{
if (TREE_CODE (expr) != PTRMEM_CST)
goto bad_argument;
}
else if (TYPE_PTR_P (expr_type)
|| TREE_CODE (expr_type) == ARRAY_TYPE
|| TREE_CODE (type) == REFERENCE_TYPE
/* If expr is the address of an overloaded function, we
will get the unknown_type_node at this point. */
|| expr_type == unknown_type_node)
{
tree referent;
tree e = expr;
STRIP_NOPS (e);
if (TREE_CODE (expr_type) == ARRAY_TYPE
|| (TREE_CODE (type) == REFERENCE_TYPE
&& TREE_CODE (e) != ADDR_EXPR))
referent = e;
else
{
if (TREE_CODE (e) != ADDR_EXPR)
{
bad_argument:
error ("`%E' is not a valid template argument", expr);
if (TYPE_PTR_P (expr_type))
{
if (TREE_CODE (TREE_TYPE (expr_type)) == FUNCTION_TYPE)
error ("it must be the address of a function with external linkage");
else
error ("it must be the address of an object with external linkage");
}
else if (TYPE_PTR_TO_MEMBER_P (expr_type))
error ("it must be a pointer-to-member of the form `&X::Y'");
return NULL_TREE;
}
referent = TREE_OPERAND (e, 0);
STRIP_NOPS (referent);
}
if (TREE_CODE (referent) == STRING_CST)
{
error ("string literal %E is not a valid template argument because it is the address of an object with static linkage",
referent);
return NULL_TREE;
}
if (TREE_CODE (referent) == SCOPE_REF)
referent = TREE_OPERAND (referent, 1);
if (is_overloaded_fn (referent))
/* We'll check that it has external linkage later. */
;
else if (TREE_CODE (referent) != VAR_DECL)
goto bad_argument;
else if (!DECL_EXTERNAL_LINKAGE_P (referent))
{
error ("address of non-extern `%E' cannot be used as template argument", referent);
return error_mark_node;
}
}
else if (INTEGRAL_TYPE_P (expr_type) || TYPE_PTR_TO_MEMBER_P (expr_type))
{
if (! TREE_CONSTANT (expr))
{
non_constant:
error ("non-constant `%E' cannot be used as template argument",
expr);
return NULL_TREE;
}
}
else
{
if (TYPE_P (expr))
error ("type '%T' cannot be used as a value for a non-type "
"template-parameter", expr);
else if (DECL_P (expr))
error ("invalid use of '%D' as a non-type template-argument", expr);
else
error ("invalid use of '%E' as a non-type template-argument", expr);
return NULL_TREE;
}
switch (TREE_CODE (type))
{
case INTEGER_TYPE:
case BOOLEAN_TYPE:
case ENUMERAL_TYPE:
/* For a non-type template-parameter of integral or enumeration
type, integral promotions (_conv.prom_) and integral
conversions (_conv.integral_) are applied. */
if (!INTEGRAL_TYPE_P (expr_type))
return error_mark_node;
/* It's safe to call digest_