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