gcc/c-objc-common.c

   1 /* Some code common to C and ObjC front ends.
   2    Copyright (C) 2001 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 2, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING.  If not, write to the Free
  18 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  19 02111-1307, USA.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "tree.h"
  24 #include "rtl.h"
  25 #include "insn-config.h"
  26 #include "integrate.h"
  27 #include "expr.h"
  28 #include "c-tree.h"
  29 #include "function.h"
  30 #include "flags.h"
  31 #include "toplev.h"
  32 #include "diagnostic.h"
  33 #include "tree-inline.h"
  34 #include "varray.h"
  35 #include "ggc.h"
  36 #include "langhooks.h"
  37
  38 static int c_tree_printer PARAMS ((output_buffer *));
  39 static tree inline_forbidden_p PARAMS ((tree *, int *, void *));
  40 static void expand_deferred_fns PARAMS ((void));
  41 static tree start_cdtor PARAMS ((int));
  42 static void finish_cdtor PARAMS ((tree));
  43
  44 static varray_type deferred_fns;
  45
  46 int
  47 c_missing_noreturn_ok_p (decl)
  48      tree decl;
  49 {
  50   /* A missing noreturn is not ok for freestanding implementations and
  51      ok for the `main' function in hosted implementations.  */
  52   return flag_hosted && MAIN_NAME_P (DECL_ASSEMBLER_NAME (decl));
  53 }
  54
  55 /* We want to inline `extern inline' functions even if this would
  56    violate inlining limits.  Some glibc and linux constructs depend on
  57    such functions always being inlined when optimizing.  */
  58
  59 int
  60 c_disregard_inline_limits (fn)
  61      tree fn;
  62 {
  63   if (lookup_attribute ("always_inline", DECL_ATTRIBUTES (fn)) != NULL)
  64     return 1;
  65
  66   return DECL_DECLARED_INLINE_P (fn) && DECL_EXTERNAL (fn);
  67 }
  68
  69 static tree
  70 inline_forbidden_p (nodep, walk_subtrees, fn)
  71      tree *nodep;
  72      int *walk_subtrees ATTRIBUTE_UNUSED;
  73      void *fn;
  74 {
  75   tree node = *nodep;
  76   tree t;
  77
  78   switch (TREE_CODE (node))
  79     {
  80     case CALL_EXPR:
  81       t = get_callee_fndecl (node);
  82
  83       if (! t)
  84         break;
  85
  86       /* We cannot inline functions that call setjmp.  */
  87       if (setjmp_call_p (t))
  88         return node;
  89
  90       switch (DECL_FUNCTION_CODE (t))
  91         {
  92           /* We cannot inline functions that take a variable number of
  93              arguments.  */
  94         case BUILT_IN_VARARGS_START:
  95         case BUILT_IN_STDARG_START:
  96 #if 0
  97           /* Functions that need information about the address of the
  98              caller can't (shouldn't?) be inlined.  */
  99         case BUILT_IN_RETURN_ADDRESS:
 100 #endif
 101           return node;
 102
 103         default:
 104           break;
 105         }
 106
 107       break;
 108
 109     case DECL_STMT:
 110       /* We cannot inline functions that contain other functions.  */
 111       if (TREE_CODE (TREE_OPERAND (node, 0)) == FUNCTION_DECL
 112           && DECL_INITIAL (TREE_OPERAND (node, 0)))
 113         return node;
 114       break;
 115
 116     case GOTO_STMT:
 117     case GOTO_EXPR:
 118       t = TREE_OPERAND (node, 0);
 119
 120       /* We will not inline a function which uses computed goto.  The
 121          addresses of its local labels, which may be tucked into
 122          global storage, are of course not constant across
 123          instantiations, which causes unexpected behaviour.  */
 124       if (TREE_CODE (t) != LABEL_DECL)
 125         return node;
 126
 127       /* We cannot inline a nested function that jumps to a nonlocal
 128          label.  */
 129       if (TREE_CODE (t) == LABEL_DECL
 130           && DECL_CONTEXT (t) && DECL_CONTEXT (t) != fn)
 131         return node;
 132
 133       break;
 134
 135     default:
 136       break;
 137     }
 138
 139   return NULL_TREE;
 140 }
 141
 142 int
 143 c_cannot_inline_tree_fn (fnp)
 144      tree *fnp;
 145 {
 146   tree fn = *fnp;
 147   tree t;
 148
 149   if (flag_really_no_inline
 150       && lookup_attribute ("always_inline", DECL_ATTRIBUTES (fn)) == NULL)
 151     return 1;
 152
 153   if (! function_attribute_inlinable_p (fn))
 154     {
 155       DECL_UNINLINABLE (fn) = 1;
 156       return 1;
 157     }
 158
 159   /* If a function has pending sizes, we must not defer its
 160      compilation, and we can't inline it as a tree.  */
 161   if (fn == current_function_decl)
 162     {
 163       t = get_pending_sizes ();
 164       put_pending_sizes (t);
 165
 166       if (t)
 167         {
 168           DECL_UNINLINABLE (fn) = 1;
 169           return 1;
 170         }
 171     }
 172
 173   if (DECL_CONTEXT (fn))
 174     {
 175       /* If a nested function has pending sizes, we may have already
 176          saved them.  */
 177       if (DECL_LANG_SPECIFIC (fn)->pending_sizes)
 178         {
 179           DECL_UNINLINABLE (fn) = 1;
 180           return 1;
 181         }
 182     }
 183   else
 184     {
 185       /* We rely on the fact that this function is called upfront,
 186          just before we start expanding a function.  If FN is active
 187          (i.e., it's the current_function_decl or a parent thereof),
 188          we have to walk FN's saved tree.  Otherwise, we can safely
 189          assume we have done it before and, if we didn't mark it as
 190          uninlinable (in which case we wouldn't have been called), it
 191          is inlinable.  Unfortunately, this strategy doesn't work for
 192          nested functions, because they're only expanded as part of
 193          their enclosing functions, so the inlinability test comes in
 194          late.  */
 195       t = current_function_decl;
 196
 197       while (t && t != fn)
 198         t = DECL_CONTEXT (t);
 199       if (! t)
 200         return 0;
 201     }
 202
 203   if (walk_tree (&DECL_SAVED_TREE (fn), inline_forbidden_p, fn, NULL))
 204     {
 205       DECL_UNINLINABLE (fn) = 1;
 206       return 1;
 207     }
 208
 209   return 0;
 210 }
 211
 212 /* Initialization common to C and Objective-C front ends.  */
 213 const char *
 214 c_objc_common_init (filename)
 215      const char *filename;
 216 {
 217   c_init_decl_processing ();
 218
 219   filename = c_common_init (filename);
 220   if (filename == NULL)
 221     return NULL;
 222
 223   lang_unsafe_for_reeval = c_unsafe_for_reeval;
 224
 225   save_lang_status = &push_c_function_context;
 226   restore_lang_status = &pop_c_function_context;
 227   mark_lang_status = &mark_c_function_context;
 228   lang_expand_expr = c_expand_expr;
 229   lang_expand_decl_stmt = c_expand_decl_stmt;
 230
 231   /* These were not defined in the Objective-C front end, but I'm
 232      putting them here anyway.  The diagnostic format decoder might
 233      want an enhanced ObjC implementation.  */
 234   diagnostic_format_decoder (global_dc) = &c_tree_printer;
 235   lang_missing_noreturn_ok_p = &c_missing_noreturn_ok_p;
 236
 237   /* If still unspecified, make it match -std=c99
 238      (allowing for -pedantic-errors).  */
 239   if (mesg_implicit_function_declaration < 0)
 240     {
 241       if (flag_isoc99)
 242         mesg_implicit_function_declaration = flag_pedantic_errors ? 2 : 1;
 243       else
 244         mesg_implicit_function_declaration = 0;
 245     }
 246
 247   VARRAY_TREE_INIT (deferred_fns, 32, "deferred_fns");
 248   ggc_add_tree_varray_root (&deferred_fns, 1);
 249
 250   return filename;
 251 }
 252
 253 /* Register a function tree, so that its optimization and conversion
 254    to RTL is only done at the end of the compilation.  */
 255
 256 int
 257 defer_fn (fn)
 258      tree fn;
 259 {
 260   VARRAY_PUSH_TREE (deferred_fns, fn);
 261
 262   return 1;
 263 }
 264
 265 /* Expand deferred functions for C and ObjC.  */
 266
 267 static void
 268 expand_deferred_fns ()
 269 {
 270   unsigned int i;
 271
 272   for (i = 0; i < VARRAY_ACTIVE_SIZE (deferred_fns); i++)
 273     {
 274       tree decl = VARRAY_TREE (deferred_fns, i);
 275
 276       if (! TREE_ASM_WRITTEN (decl))
 277         {
 278           /* For static inline functions, delay the decision whether to
 279              emit them or not until wrapup_global_declarations.  */
 280           if (! TREE_PUBLIC (decl))
 281             DECL_DEFER_OUTPUT (decl) = 1;
 282           c_expand_deferred_function (decl);
 283         }
 284     }
 285
 286   VARRAY_FREE (deferred_fns);
 287 }
 288
 289 static tree
 290 start_cdtor (method_type)
 291      int method_type;
 292 {
 293   tree fnname = get_file_function_name (method_type);
 294   tree void_list_node_1 = build_tree_list (NULL_TREE, void_type_node);
 295   tree body;
 296
 297   start_function (void_list_node_1,
 298                   build_nt (CALL_EXPR, fnname,
 299                             tree_cons (NULL_TREE, NULL_TREE, void_list_node_1),
 300                             NULL_TREE),
 301                   NULL_TREE);
 302   store_parm_decls ();
 303
 304   current_function_cannot_inline
 305     = "static constructors and destructors cannot be inlined";
 306
 307   body = c_begin_compound_stmt ();
 308
 309   pushlevel (0);
 310   clear_last_expr ();
 311   add_scope_stmt (/*begin_p=*/1, /*partial_p=*/0);
 312
 313   return body;
 314 }
 315
 316 static void
 317 finish_cdtor (body)
 318      tree body;
 319 {
 320   tree scope;
 321   tree block;
 322
 323   scope = add_scope_stmt (/*begin_p=*/0, /*partial_p=*/0);
 324   block = poplevel (0, 0, 0);
 325   SCOPE_STMT_BLOCK (TREE_PURPOSE (scope)) = block;
 326   SCOPE_STMT_BLOCK (TREE_VALUE (scope)) = block;
 327
 328   RECHAIN_STMTS (body, COMPOUND_BODY (body));
 329
 330   finish_function (0);
 331 }
 332
 333 /* Called at end of parsing, but before end-of-file processing.  */
 334
 335 void
 336 c_objc_common_finish_file ()
 337 {
 338   expand_deferred_fns ();
 339
 340   if (static_ctors)
 341     {
 342       tree body = start_cdtor ('I');
 343
 344       for (; static_ctors; static_ctors = TREE_CHAIN (static_ctors))
 345         c_expand_expr_stmt (build_function_call (TREE_VALUE (static_ctors),
 346                                                  NULL_TREE));
 347
 348       finish_cdtor (body);
 349     }
 350
 351   if (static_dtors)
 352     {
 353       tree body = start_cdtor ('D');
 354
 355       for (; static_dtors; static_dtors = TREE_CHAIN (static_dtors))
 356         c_expand_expr_stmt (build_function_call (TREE_VALUE (static_dtors),
 357                                                  NULL_TREE));
 358
 359       finish_cdtor (body);
 360     }
 361
 362   {
 363     int flags;
 364     FILE *stream = dump_begin (TDI_all, &flags);
 365
 366     if (stream)
 367       {
 368         dump_node (getdecls (), flags & ~TDF_SLIM, stream);
 369         dump_end (TDI_all, stream);
 370       }
 371   }
 372 }
 373
 374 /* Called during diagnostic message formatting process to print a
 375    source-level entity onto BUFFER.  The meaning of the format specifiers
 376    is as follows:
 377    %D: a general decl,
 378    %F: a function declaration,
 379    %T: a type.
 380
 381    These format specifiers form a subset of the format specifiers set used
 382    by the C++ front-end.
 383    Please notice when called, the `%' part was already skipped by the
 384    diagnostic machinery.  */
 385 static int
 386 c_tree_printer (buffer)
 387      output_buffer *buffer;
 388 {
 389   tree t = va_arg (output_buffer_format_args (buffer), tree);
 390
 391   switch (*output_buffer_text_cursor (buffer))
 392     {
 393     case 'D':
 394     case 'F':
 395     case 'T':
 396       {
 397         const char *n = DECL_NAME (t)
 398           ? (*lang_hooks.decl_printable_name) (t, 2)
 399           : "({anonymous})";
 400         output_add_string (buffer, n);
 401       }
 402       return 1;
 403
 404     default:
 405       return 0;
 406     }
 407 }