gcc/cp/cp-objcp-common.c

   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
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING.  If not, write to the Free
  19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  20 02111-1307, 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
  39 HOST_WIDE_INT
  40 cxx_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
  56 bool
  57 cxx_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
  75 tree
  76 cp_expr_size (tree exp)
  77 {
  78   if (CLASS_TYPE_P (TREE_TYPE (exp)))
  79     {
  80       /* The backend should not be interested in the size of an expression
  81          of a type with both of these set; all copies of such types must go
  82          through a constructor or assignment op.  */
  83       gcc_assert (!TYPE_HAS_COMPLEX_INIT_REF (TREE_TYPE (exp))
  84                   || !TYPE_HAS_COMPLEX_ASSIGN_REF (TREE_TYPE (exp))
  85                   /* But storing a CONSTRUCTOR isn't a copy.  */
  86                   || TREE_CODE (exp) == CONSTRUCTOR);
  87
  88       /* This would be wrong for a type with virtual bases, but they are
  89          caught by the assert above.  */
  90       return (is_empty_class (TREE_TYPE (exp))
  91               ? size_zero_node
  92               : CLASSTYPE_SIZE_UNIT (TREE_TYPE (exp)));
  93     }
  94   else
  95     /* Use the default code.  */
  96     return lhd_expr_size (exp);
  97 }
  98
  99 /* Langhook for tree_size: determine size of our 'x' and 'c' nodes.  */
 100 size_t
 101 cp_tree_size (enum tree_code code)
 102 {
 103   switch (code)
 104     {
 105     case TINST_LEVEL:           return sizeof (struct tinst_level_s);
 106     case PTRMEM_CST:            return sizeof (struct ptrmem_cst);
 107     case BASELINK:              return sizeof (struct tree_baselink);
 108     case TEMPLATE_PARM_INDEX:   return sizeof (template_parm_index);
 109     case DEFAULT_ARG:           return sizeof (struct tree_default_arg);
 110     case OVERLOAD:              return sizeof (struct tree_overload);
 111     default:
 112       gcc_unreachable ();
 113     }
 114   /* NOTREACHED */
 115 }
 116
 117 /* Returns true if T is a variably modified type, in the sense of C99.
 118    FN is as passed to variably_modified_p.
 119    This routine needs only check cases that cannot be handled by the
 120    language-independent logic in tree.c.  */
 121
 122 bool
 123 cp_var_mod_type_p (tree type, tree fn)
 124 {
 125   /* If TYPE is a pointer-to-member, it is variably modified if either
 126      the class or the member are variably modified.  */
 127   if (TYPE_PTR_TO_MEMBER_P (type))
 128     return (variably_modified_type_p (TYPE_PTRMEM_CLASS_TYPE (type), fn)
 129             || variably_modified_type_p (TYPE_PTRMEM_POINTED_TO_TYPE (type),
 130                                          fn));
 131
 132   /* All other types are not variably modified.  */
 133   return false;
 134 }
 135
 136 /* Construct a C++-aware pretty-printer for CONTEXT.  It is assumed
 137    that CONTEXT->printer is an already constructed basic pretty_printer.  */
 138 void
 139 cxx_initialize_diagnostics (diagnostic_context *context)
 140 {
 141   pretty_printer *base = context->printer;
 142   cxx_pretty_printer *pp = xmalloc (sizeof (cxx_pretty_printer));
 143   memcpy (pp_base (pp), base, sizeof (pretty_printer));
 144   pp_cxx_pretty_printer_init (pp);
 145   context->printer = (pretty_printer *) pp;
 146
 147   /* It is safe to free this object because it was previously malloc()'d.  */
 148   free (base);
 149 }
 150
 151 /* This compares two types for equivalence ("compatible" in C-based languages).
 152    This routine should only return 1 if it is sure.  It should not be used
 153    in contexts where erroneously returning 0 causes problems.  */
 154
 155 int
 156 cxx_types_compatible_p (tree x, tree y)
 157 {
 158   if (same_type_ignoring_top_level_qualifiers_p (x, y))
 159     return 1;
 160
 161   /* Once we get to the middle-end, references and pointers are
 162      interchangeable.  FIXME should we try to replace all references with
 163      pointers?  */
 164   if (POINTER_TYPE_P (x) && POINTER_TYPE_P (y)
 165       && TYPE_MODE (x) == TYPE_MODE (y)
 166       && TYPE_REF_CAN_ALIAS_ALL (x) == TYPE_REF_CAN_ALIAS_ALL (y)
 167       && same_type_p (TREE_TYPE (x), TREE_TYPE (y)))
 168     return 1;
 169
 170   return 0;
 171 }
 172
 173 /* Stubs to keep c-opts.c happy.  */
 174 void
 175 push_file_scope (void)
 176 {
 177 }
 178
 179 void
 180 pop_file_scope (void)
 181 {
 182 }
 183
 184 /* c-pragma.c needs to query whether a decl has extern "C" linkage.  */
 185 bool
 186 has_c_linkage (tree decl)
 187 {
 188   return DECL_EXTERN_C_P (decl);
 189 }