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