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 /* Called from check_global_declarations.  */
 213
 214 bool
 215 c_warn_unused_global_decl (decl)
 216      tree decl;
 217 {
 218   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (decl))
 219     return false;
 220   if (DECL_IN_SYSTEM_HEADER (decl))
 221     return false;
 222
 223   return true;
 224 }
 225
 226 /* Initialization common to C and Objective-C front ends.  */
 227 const char *
 228 c_objc_common_init (filename)
 229      const char *filename;
 230 {
 231   c_init_decl_processing ();
 232
 233   filename = c_common_init (filename);
 234   if (filename == NULL)
 235     return NULL;
 236
 237   lang_expand_decl_stmt = c_expand_decl_stmt;
 238
 239   /* These were not defined in the Objective-C front end, but I'm
 240      putting them here anyway.  The diagnostic format decoder might
 241      want an enhanced ObjC implementation.  */
 242   diagnostic_format_decoder (global_dc) = &c_tree_printer;
 243   lang_missing_noreturn_ok_p = &c_missing_noreturn_ok_p;
 244
 245   /* If still unspecified, make it match -std=c99
 246      (allowing for -pedantic-errors).  */
 247   if (mesg_implicit_function_declaration < 0)
 248     {
 249       if (flag_isoc99)
 250         mesg_implicit_function_declaration = flag_pedantic_errors ? 2 : 1;
 251       else
 252         mesg_implicit_function_declaration = 0;
 253     }
 254
 255   VARRAY_TREE_INIT (deferred_fns, 32, "deferred_fns");
 256   ggc_add_tree_varray_root (&deferred_fns, 1);
 257
 258   return filename;
 259 }
 260
 261 /* Register a function tree, so that its optimization and conversion
 262    to RTL is only done at the end of the compilation.  */
 263
 264 int
 265 defer_fn (fn)
 266      tree fn;
 267 {
 268   VARRAY_PUSH_TREE (deferred_fns, fn);
 269
 270   return 1;
 271 }
 272
 273 /* Expand deferred functions for C and ObjC.  */
 274
 275 static void
 276 expand_deferred_fns ()
 277 {
 278   unsigned int i;
 279
 280   for (i = 0; i < VARRAY_ACTIVE_SIZE (deferred_fns); i++)
 281     {
 282       tree decl = VARRAY_TREE (deferred_fns, i);
 283
 284       if (! TREE_ASM_WRITTEN (decl))
 285         {
 286           /* For static inline functions, delay the decision whether to
 287              emit them or not until wrapup_global_declarations.  */
 288           if (! TREE_PUBLIC (decl))
 289             DECL_DEFER_OUTPUT (decl) = 1;
 290           c_expand_deferred_function (decl);
 291         }
 292     }
 293
 294   VARRAY_FREE (deferred_fns);
 295 }
 296
 297 static tree
 298 start_cdtor (method_type)
 299      int method_type;
 300 {
 301   tree fnname = get_file_function_name (method_type);
 302   tree void_list_node_1 = build_tree_list (NULL_TREE, void_type_node);
 303   tree body;
 304
 305   start_function (void_list_node_1,
 306                   build_nt (CALL_EXPR, fnname,
 307                             tree_cons (NULL_TREE, NULL_TREE, void_list_node_1),
 308                             NULL_TREE),
 309                   NULL_TREE);
 310   store_parm_decls ();
 311
 312   current_function_cannot_inline
 313     = "static constructors and destructors cannot be inlined";
 314
 315   body = c_begin_compound_stmt ();
 316
 317   pushlevel (0);
 318   clear_last_expr ();
 319   add_scope_stmt (/*begin_p=*/1, /*partial_p=*/0);
 320
 321   return body;
 322 }
 323
 324 static void
 325 finish_cdtor (body)
 326      tree body;
 327 {
 328   tree scope;
 329   tree block;
 330
 331   scope = add_scope_stmt (/*begin_p=*/0, /*partial_p=*/0);
 332   block = poplevel (0, 0, 0);
 333   SCOPE_STMT_BLOCK (TREE_PURPOSE (scope)) = block;
 334   SCOPE_STMT_BLOCK (TREE_VALUE (scope)) = block;
 335
 336   RECHAIN_STMTS (body, COMPOUND_BODY (body));
 337
 338   finish_function (0, 0);
 339 }
 340
 341 /* Called at end of parsing, but before end-of-file processing.  */
 342
 343 void
 344 c_objc_common_finish_file ()
 345 {
 346   expand_deferred_fns ();
 347
 348   if (static_ctors)
 349     {
 350       tree body = start_cdtor ('I');
 351
 352       for (; static_ctors; static_ctors = TREE_CHAIN (static_ctors))
 353         c_expand_expr_stmt (build_function_call (TREE_VALUE (static_ctors),
 354                                                  NULL_TREE));
 355
 356       finish_cdtor (body);
 357     }
 358
 359   if (static_dtors)
 360     {
 361       tree body = start_cdtor ('D');
 362
 363       for (; static_dtors; static_dtors = TREE_CHAIN (static_dtors))
 364         c_expand_expr_stmt (build_function_call (TREE_VALUE (static_dtors),
 365                                                  NULL_TREE));
 366
 367       finish_cdtor (body);
 368     }
 369
 370   {
 371     int flags;
 372     FILE *stream = dump_begin (TDI_all, &flags);
 373
 374     if (stream)
 375       {
 376         dump_node (getdecls (), flags & ~TDF_SLIM, stream);
 377         dump_end (TDI_all, stream);
 378       }
 379   }
 380 }
 381
 382 /* Called during diagnostic message formatting process to print a
 383    source-level entity onto BUFFER.  The meaning of the format specifiers
 384    is as follows:
 385    %D: a general decl,
 386    %F: a function declaration,
 387    %T: a type.
 388
 389    These format specifiers form a subset of the format specifiers set used
 390    by the C++ front-end.
 391    Please notice when called, the `%' part was already skipped by the
 392    diagnostic machinery.  */
 393 static int
 394 c_tree_printer (buffer)
 395      output_buffer *buffer;
 396 {
 397   tree t = va_arg (output_buffer_format_args (buffer), tree);
 398
 399   switch (*output_buffer_text_cursor (buffer))
 400     {
 401     case 'D':
 402     case 'F':
 403     case 'T':
 404       {
 405         const char *n = DECL_NAME (t)
 406           ? (*lang_hooks.decl_printable_name) (t, 2)
 407           : "({anonymous})";
 408         output_add_string (buffer, n);
 409       }
 410       return 1;
 411
 412     default:
 413       return 0;
 414     }
 415 }