1/* Some code common to C++ and ObjC++ front ends.
2   Copyright (C) 2004 Free Software Foundation, Inc.
3   Contributed by Ziemowit Laski  <zlaski@apple.com>
4
5This file is part of GCC.
6
7GCC is free software; you can redistribute it and/or modify it under
8the terms of the GNU General Public License as published by the Free
9Software Foundation; either version 2, or (at your option) any later
10version.
11
12GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13WARRANTY; without even the implied warranty of MERCHANTABILITY or
14FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
15for more details.
16
17You should have received a copy of the GNU General Public License
18along with GCC; see the file COPYING.  If not, write to the Free
19Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
2002110-1301, USA.  */
21
22#include "config.h"
23#include "system.h"
24#include "coretypes.h"
25#include "tm.h"
26#include "tree.h"
27#include "cp-tree.h"
28#include "c-common.h"
29#include "toplev.h"
30#include "langhooks.h"
31#include "langhooks-def.h"
32#include "diagnostic.h"
33#include "debug.h"
34#include "cxx-pretty-print.h"
35#include "cp-objcp-common.h"
36
37/* Special routine to get the alias set for C++.  */
38
39HOST_WIDE_INT
40cxx_get_alias_set (tree t)
41{
42  if (IS_FAKE_BASE_TYPE (t))
43    /* The base variant of a type must be in the same alias set as the
44       complete type.  */
45    return get_alias_set (TYPE_CONTEXT (t));
46
47  /* Punt on PMFs until we canonicalize functions properly.  */
48  if (TYPE_PTRMEMFUNC_P (t))
49    return 0;
50
51  return c_common_get_alias_set (t);
52}
53
54/* Called from check_global_declarations.  */
55
56bool
57cxx_warn_unused_global_decl (tree decl)
58{
59  if (TREE_CODE (decl) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (decl))
60    return false;
61  if (DECL_IN_SYSTEM_HEADER (decl))
62    return false;
63
64  /* Const variables take the place of #defines in C++.  */
65  if (TREE_CODE (decl) == VAR_DECL && TREE_READONLY (decl))
66    return false;
67
68  return true;
69}
70
71/* Langhook for expr_size: Tell the backend that the value of an expression
72   of non-POD class type does not include any tail padding; a derived class
73   might have allocated something there.  */
74
75tree
76cp_expr_size (tree exp)
77{
78  tree type = TREE_TYPE (exp);
79
80  if (CLASS_TYPE_P (type))
81    {
82      /* The backend should not be interested in the size of an expression
83	 of a type with both of these set; all copies of such types must go
84	 through a constructor or assignment op.  */
85      gcc_assert (!TYPE_HAS_COMPLEX_INIT_REF (type)
86		  || !TYPE_HAS_COMPLEX_ASSIGN_REF (type)
87		  /* But storing a CONSTRUCTOR isn't a copy.  */
88		  || TREE_CODE (exp) == CONSTRUCTOR
89		  /* And, the gimplifier will sometimes make a copy of
90		     an aggregate.  In particular, for a case like:
91
92			struct S { S(); };
93			struct X { int a; S s; };
94			X x = { 0 };
95
96		     the gimplifier will create a temporary with
97		     static storage duration, perform static
98		     initialization of the temporary, and then copy
99		     the result.  Since the "s" subobject is never
100		     constructed, this is a valid transformation.  */
101		  || CP_AGGREGATE_TYPE_P (type));
102
103      /* This would be wrong for a type with virtual bases, but they are
104	 caught by the assert above.  */
105      return (is_empty_class (type)
106	      ? size_zero_node
107	      : CLASSTYPE_SIZE_UNIT (type));
108    }
109  else
110    /* Use the default code.  */
111    return lhd_expr_size (exp);
112}
113
114/* Langhook for tree_size: determine size of our 'x' and 'c' nodes.  */
115size_t
116cp_tree_size (enum tree_code code)
117{
118  switch (code)
119    {
120    case TINST_LEVEL:		return sizeof (struct tinst_level_s);
121    case PTRMEM_CST:		return sizeof (struct ptrmem_cst);
122    case BASELINK:		return sizeof (struct tree_baselink);
123    case TEMPLATE_PARM_INDEX:	return sizeof (template_parm_index);
124    case DEFAULT_ARG:		return sizeof (struct tree_default_arg);
125    case OVERLOAD:		return sizeof (struct tree_overload);
126    default:
127      gcc_unreachable ();
128    }
129  /* NOTREACHED */
130}
131
132/* Returns true if T is a variably modified type, in the sense of C99.
133   FN is as passed to variably_modified_p.
134   This routine needs only check cases that cannot be handled by the
135   language-independent logic in tree.c.  */
136
137bool
138cp_var_mod_type_p (tree type, tree fn)
139{
140  /* If TYPE is a pointer-to-member, it is variably modified if either
141     the class or the member are variably modified.  */
142  if (TYPE_PTR_TO_MEMBER_P (type))
143    return (variably_modified_type_p (TYPE_PTRMEM_CLASS_TYPE (type), fn)
144	    || variably_modified_type_p (TYPE_PTRMEM_POINTED_TO_TYPE (type),
145					 fn));
146
147  /* All other types are not variably modified.  */
148  return false;
149}
150
151/* Construct a C++-aware pretty-printer for CONTEXT.  It is assumed
152   that CONTEXT->printer is an already constructed basic pretty_printer.  */
153void
154cxx_initialize_diagnostics (diagnostic_context *context)
155{
156  pretty_printer *base = context->printer;
157  cxx_pretty_printer *pp = XNEW (cxx_pretty_printer);
158  memcpy (pp_base (pp), base, sizeof (pretty_printer));
159  pp_cxx_pretty_printer_init (pp);
160  context->printer = (pretty_printer *) pp;
161
162  /* It is safe to free this object because it was previously malloc()'d.  */
163  free (base);
164}
165
166/* This compares two types for equivalence ("compatible" in C-based languages).
167   This routine should only return 1 if it is sure.  It should not be used
168   in contexts where erroneously returning 0 causes problems.  */
169
170int
171cxx_types_compatible_p (tree x, tree y)
172{
173  if (same_type_ignoring_top_level_qualifiers_p (x, y))
174    return 1;
175
176  /* Once we get to the middle-end, references and pointers are
177     interchangeable.  FIXME should we try to replace all references with
178     pointers?  */
179  if (POINTER_TYPE_P (x) && POINTER_TYPE_P (y)
180      && TYPE_MODE (x) == TYPE_MODE (y)
181      && TYPE_REF_CAN_ALIAS_ALL (x) == TYPE_REF_CAN_ALIAS_ALL (y)
182      && same_type_p (TREE_TYPE (x), TREE_TYPE (y)))
183    return 1;
184
185  return 0;
186}
187
188tree
189cxx_staticp (tree arg)
190{
191  switch (TREE_CODE (arg))
192    {
193    case BASELINK:
194      return staticp (BASELINK_FUNCTIONS (arg));
195
196    default:
197      break;
198    }
199
200  return NULL_TREE;
201}
202
203/* Stubs to keep c-opts.c happy.  */
204void
205push_file_scope (void)
206{
207}
208
209void
210pop_file_scope (void)
211{
212}
213
214/* c-pragma.c needs to query whether a decl has extern "C" linkage.  */
215bool
216has_c_linkage (tree decl)
217{
218  return DECL_EXTERN_C_P (decl);
219}
220
221static GTY ((if_marked ("tree_map_marked_p"), param_is (struct tree_map)))
222     htab_t shadowed_var_for_decl;
223
224/* Lookup a shadowed var for FROM, and return it if we find one.  */
225
226tree
227decl_shadowed_for_var_lookup (tree from)
228{
229  struct tree_map *h, in;
230  in.from = from;
231
232  h = (struct tree_map *) htab_find_with_hash (shadowed_var_for_decl, &in,
233					       htab_hash_pointer (from));
234  if (h)
235    return h->to;
236  return NULL_TREE;
237}
238
239/* Insert a mapping FROM->TO in the shadowed var hashtable.  */
240
241void
242decl_shadowed_for_var_insert (tree from, tree to)
243{
244  struct tree_map *h;
245  void **loc;
246
247  h = GGC_NEW (struct tree_map);
248  h->hash = htab_hash_pointer (from);
249  h->from = from;
250  h->to = to;
251  loc = htab_find_slot_with_hash (shadowed_var_for_decl, h, h->hash, INSERT);
252  *(struct tree_map **) loc = h;
253}
254
255void
256init_shadowed_var_for_decl (void)
257{
258  shadowed_var_for_decl = htab_create_ggc (512, tree_map_hash,
259					   tree_map_eq, 0);
260}
261
262
263#include "gt-cp-cp-objcp-common.h"
264