gcc/cp/optimize.c

   1 /* Perform optimizations on tree structure.
   2
   3    Copyright (C) 1998, 1999, 2000 Free Software Foundation, Inc.
   4    Written by Mark Michell (mark@codesourcery.com).
   5
   6    This file is part of GNU CC.
   7
   8    GNU CC is free software; you can redistribute it and/or modify it
   9    under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2, or (at your option)
  11    any later version.
  12
  13    GNU CC is distributed in the hope that it will be useful, but
  14    WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16    General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with GNU CC; see the file COPYING.  If not, write to the Free
  20    Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  21    02111-1307, USA.  */
  22
  23 #include "config.h"
  24 #include "system.h"
  25 #include "tree.h"
  26 #include "cp-tree.h"
  27 #include "rtl.h"
  28 #include "insn-config.h"
  29 #include "integrate.h"
  30 #include "varray.h"
  31
  32 /* To Do:
  33
  34    o In order to make inlining-on-trees work, we pessimized
  35      function-local static constants.  In particular, they are now
  36      always output, even when not addressed.  Fix this by treating
  37      function-local static constants just like global static
  38      constants; the back-end already knows not to output them if they
  39      are not needed.
  40
  41    o Provide heuristics to clamp inlining of recursive template
  42      calls?
  43
  44    o It looks like the return label is not being placed in the optimal
  45      place.  Shouldn't it come before the returned value?  */
  46
  47 /* Data required for function inlining.  */
  48
  49 typedef struct inline_data
  50 {
  51   /* A stack of the functions we are inlining.  For example, if we are
  52      compiling `f', which calls `g', which calls `h', and we are
  53      inlining the body of `h', the stack will contain, `h', followed
  54      by `g', followed by `f'.  */
  55   varray_type fns;
  56   /* The label to jump to when a return statement is encountered.  */
  57   tree ret_label;
  58   /* The map from local declarations in the inlined function to
  59      equivalents in the function into which it is being inlined.  */
  60   splay_tree decl_map;
  61   /* Nonzero if we are currently within the cleanup for a
  62      TARGET_EXPR.  */
  63   int in_target_cleanup_p;
  64 } inline_data;
  65
  66 /* Prototypes.  */
  67
  68 static tree initialize_inlined_parameters PARAMS ((inline_data *, tree, tree));
  69 static tree declare_return_variable PARAMS ((inline_data *, tree *));
  70 static tree copy_body_r PARAMS ((tree *, int *, void *));
  71 static tree copy_body PARAMS ((inline_data *));
  72 static tree expand_call_inline PARAMS ((tree *, int *, void *));
  73 static void expand_calls_inline PARAMS ((tree *, inline_data *));
  74 static int inlinable_function_p PARAMS ((tree, inline_data *));
  75 static tree remap_decl PARAMS ((tree, inline_data *));
  76 static void remap_block PARAMS ((tree, tree, inline_data *));
  77 static void copy_scope_stmt PARAMS ((tree *, int *, inline_data *));
  78 static tree calls_setjmp_r PARAMS ((tree *, int *, void *));
  79
  80 /* Remap DECL during the copying of the BLOCK tree for the function.
  81    DATA is really an `inline_data *'.  */
  82
  83 static tree
  84 remap_decl (decl, id)
  85      tree decl;
  86      inline_data *id;
  87 {
  88   splay_tree_node n;
  89   tree fn;
  90
  91   /* We only remap local variables in the current function.  */
  92   fn = VARRAY_TOP_TREE (id->fns);
  93   if (!nonstatic_local_decl_p (decl) || DECL_CONTEXT (decl) != fn)
  94     return NULL_TREE;
  95
  96   /* See if we have remapped this declaration.  */
  97   n = splay_tree_lookup (id->decl_map, (splay_tree_key) decl);
  98   /* If we didn't already have an equivalent for this declaration,
  99      create one now.  */
 100   if (!n)
 101     {
 102       tree t;
 103
 104       /* Make a copy of the variable or label.  */
 105       t = copy_decl_for_inlining (decl, fn,
 106                                   VARRAY_TREE (id->fns, 0));
 107       /* Remember it, so that if we encounter this local entity
 108          again we can reuse this copy.  */
 109       n = splay_tree_insert (id->decl_map,
 110                              (splay_tree_key) decl,
 111                              (splay_tree_value) t);
 112     }
 113
 114   return (tree) n->value;
 115 }
 116
 117 /* Copy the SCOPE_STMT_BLOCK associated with SCOPE_STMT to contain
 118    remapped versions of the variables therein.  And hook the new block
 119    into the block-tree.  If non-NULL, the DECLS are declarations to
 120    add to use instead of the BLOCK_VARS in the old block.  */
 121
 122 static void
 123 remap_block (scope_stmt, decls, id)
 124      tree scope_stmt;
 125      tree decls;
 126      inline_data *id;
 127 {
 128   /* We cannot do this in the cleanup for a TARGET_EXPR since we do
 129      not know whether or not expand_expr will actually write out the
 130      code we put there.  If it does not, then we'll have more BLOCKs
 131      than block-notes, and things will go awry.  At some point, we
 132      should make the back-end handle BLOCK notes in a tidier way,
 133      without requiring a strict correspondence to the block-tree; then
 134      this check can go.  */
 135   if (id->in_target_cleanup_p)
 136     {
 137       SCOPE_STMT_BLOCK (scope_stmt) = NULL_TREE;
 138       return;
 139     }
 140
 141   /* If this is the beginning of a scope, remap the associated BLOCK.  */
 142   if (SCOPE_BEGIN_P (scope_stmt) && SCOPE_STMT_BLOCK (scope_stmt))
 143     {
 144       tree old_block;
 145       tree new_block;
 146       tree old_var;
 147       tree fn;
 148
 149       /* Make the new block.  */
 150       old_block = SCOPE_STMT_BLOCK (scope_stmt);
 151       new_block = make_node (BLOCK);
 152       TREE_USED (new_block) = TREE_USED (old_block);
 153       BLOCK_ABSTRACT_ORIGIN (new_block) = old_block;
 154       SCOPE_STMT_BLOCK (scope_stmt) = new_block;
 155
 156       /* Remap its variables.  */
 157       for (old_var = decls ? decls : BLOCK_VARS (old_block);
 158            old_var;
 159            old_var = TREE_CHAIN (old_var))
 160         {
 161           tree new_var;
 162
 163           /* Remap the variable.  */
 164           new_var = remap_decl (old_var, id);
 165           if (!new_var)
 166             /* We didn't remap this variable, so we can't mess with
 167                its TREE_CHAIN.  */
 168             ;
 169           else
 170             {
 171               TREE_CHAIN (new_var) = BLOCK_VARS (new_block);
 172               BLOCK_VARS (new_block) = new_var;
 173             }
 174         }
 175       /* We put the BLOCK_VARS in reverse order; fix that now.  */
 176       BLOCK_VARS (new_block) = nreverse (BLOCK_VARS (new_block));
 177       /* Attach this new block after the DECL_INITIAL block for the
 178          function into which this block is being inlined.  In
 179          rest_of_compilation we will straighten out the BLOCK tree.  */
 180       fn = VARRAY_TREE (id->fns, 0);
 181       BLOCK_CHAIN (new_block) = BLOCK_CHAIN (DECL_INITIAL (fn));
 182       BLOCK_CHAIN (DECL_INITIAL (fn)) = new_block;
 183       /* Remember the remapped block.  */
 184       splay_tree_insert (id->decl_map,
 185                          (splay_tree_key) old_block,
 186                          (splay_tree_value) new_block);
 187     }
 188   /* If this is the end of a scope, set the SCOPE_STMT_BLOCK to be the
 189      remapped block.  */
 190   else if (SCOPE_END_P (scope_stmt) && SCOPE_STMT_BLOCK (scope_stmt))
 191     {
 192       splay_tree_node n;
 193
 194       /* Find this block in the table of remapped things.  */
 195       n = splay_tree_lookup (id->decl_map,
 196                              (splay_tree_key) SCOPE_STMT_BLOCK (scope_stmt));
 197       my_friendly_assert (n != NULL, 19991203);
 198       SCOPE_STMT_BLOCK (scope_stmt) = (tree) n->value;
 199     }
 200 }
 201
 202 /* Copy the SCOPE_STMT pointed to by TP.  */
 203
 204 static void
 205 copy_scope_stmt (tp, walk_subtrees, id)
 206      tree *tp;
 207      int *walk_subtrees;
 208      inline_data *id;
 209 {
 210   tree block;
 211
 212   /* Remember whether or not this statement was nullified.  When
 213      making a copy, copy_tree_r always sets SCOPE_NULLIFIED_P (and
 214      doesn't copy the SCOPE_STMT_BLOCK) to free callers from having to
 215      deal with copying BLOCKs if they do not wish to do so.  */
 216   block = SCOPE_STMT_BLOCK (*tp);
 217   /* Copy (and replace) the statement.  */
 218   copy_tree_r (tp, walk_subtrees, NULL);
 219   /* Restore the SCOPE_STMT_BLOCK.  */
 220   SCOPE_STMT_BLOCK (*tp) = block;
 221
 222   /* Remap the associated block.  */
 223   remap_block (*tp, NULL_TREE, id);
 224 }
 225
 226 /* Called from copy_body via walk_tree.  DATA is really an
 227    `inline_data *'.  */
 228
 229 static tree
 230 copy_body_r (tp, walk_subtrees, data)
 231      tree *tp;
 232      int *walk_subtrees;
 233      void *data;
 234 {
 235   inline_data* id;
 236   tree fn;
 237
 238   /* Set up.  */
 239   id = (inline_data *) data;
 240   fn = VARRAY_TOP_TREE (id->fns);
 241
 242   /* All automatic variables should have a DECL_CONTEXT indicating
 243      what function they come from.  */
 244   if ((TREE_CODE (*tp) == VAR_DECL || TREE_CODE (*tp) == LABEL_DECL)
 245       && DECL_NAMESPACE_SCOPE_P (*tp))
 246     my_friendly_assert (DECL_EXTERNAL (*tp) || TREE_STATIC (*tp),
 247                         19991113);
 248
 249   /* If this is a RETURN_STMT, change it into an EXPR_STMT and a
 250      GOTO_STMT with the RET_LABEL as its target.  */
 251   if (TREE_CODE (*tp) == RETURN_STMT)
 252     {
 253       tree return_stmt = *tp;
 254       tree goto_stmt;
 255
 256       /* Build the GOTO_STMT.  */
 257       goto_stmt = build_min_nt (GOTO_STMT, id->ret_label);
 258       TREE_CHAIN (goto_stmt) = TREE_CHAIN (return_stmt);
 259
 260       /* If we're returning something, just turn that into an
 261          assignment into the equivalent of the original
 262          RESULT_DECL.  */
 263       if (RETURN_EXPR (return_stmt))
 264         {
 265           *tp = build_min_nt (EXPR_STMT,
 266                               RETURN_EXPR (return_stmt));
 267           /* And then jump to the end of the function.  */
 268           TREE_CHAIN (*tp) = goto_stmt;
 269         }
 270       /* If we're not returning anything just do the jump.  */
 271       else
 272         *tp = goto_stmt;
 273     }
 274   /* Local variables and labels need to be replaced by equivalent
 275      variables.  We don't want to copy static variables; there's only
 276      one of those, no matter how many times we inline the containing
 277      function.  */
 278   else if (nonstatic_local_decl_p (*tp) && DECL_CONTEXT (*tp) == fn)
 279     {
 280       tree new_decl;
 281
 282       /* Remap the declaration.  */
 283       new_decl = remap_decl (*tp, id);
 284       my_friendly_assert (new_decl != NULL_TREE, 19991203);
 285       /* Replace this variable with the copy.  */
 286       *tp = new_decl;
 287     }
 288   else if (nonstatic_local_decl_p (*tp)
 289            && DECL_CONTEXT (*tp) != VARRAY_TREE (id->fns, 0))
 290     my_friendly_abort (0);
 291   else if (TREE_CODE (*tp) == SAVE_EXPR)
 292     remap_save_expr (tp, id->decl_map, VARRAY_TREE (id->fns, 0),
 293                      walk_subtrees);
 294   else if (TREE_CODE (*tp) == UNSAVE_EXPR)
 295     my_friendly_abort (19991113);
 296   /* For a SCOPE_STMT, we must copy the associated block so that we
 297      can write out debugging information for the inlined variables.  */
 298   else if (TREE_CODE (*tp) == SCOPE_STMT && !id->in_target_cleanup_p)
 299     copy_scope_stmt (tp, walk_subtrees, id);
 300   /* Otherwise, just copy the node.  Note that copy_tree_r already
 301      knows not to copy VAR_DECLs, etc., so this is safe.  */
 302   else
 303     {
 304       copy_tree_r (tp, walk_subtrees, NULL);
 305
 306       /* The copied TARGET_EXPR has never been expanded, even if the
 307          original node was expanded already.  */
 308       if (TREE_CODE (*tp) == TARGET_EXPR && TREE_OPERAND (*tp, 3))
 309         {
 310           TREE_OPERAND (*tp, 1) = TREE_OPERAND (*tp, 3);
 311           TREE_OPERAND (*tp, 3) = NULL_TREE;
 312         }
 313       /* Similarly, if we're copying a CALL_EXPR, the RTL for the
 314          result is no longer valid.  */
 315       else if (TREE_CODE (*tp) == CALL_EXPR)
 316         CALL_EXPR_RTL (*tp) = NULL_RTX;
 317     }
 318
 319   /* Keep iterating.  */
 320   return NULL_TREE;
 321 }
 322
 323 /* Make a copy of the body of FN so that it can be inserted inline in
 324    another function.  */
 325
 326 static tree
 327 copy_body (id)
 328      inline_data *id;
 329 {
 330   tree body;
 331
 332   body = DECL_SAVED_TREE (VARRAY_TOP_TREE (id->fns));
 333   walk_tree (&body, copy_body_r, id);
 334
 335   return body;
 336 }
 337
 338 /* Generate code to initialize the parameters of the function at the
 339    top of the stack in ID from the ARGS (presented as a TREE_LIST).  */
 340
 341 static tree
 342 initialize_inlined_parameters (id, args, fn)
 343      inline_data *id;
 344      tree args;
 345      tree fn;
 346 {
 347   tree init_stmts;
 348   tree parms;
 349   tree a;
 350   tree p;
 351
 352   /* Figure out what the parameters are.  */
 353   parms = DECL_ARGUMENTS (fn);
 354
 355   /* Start with no initializations whatsoever.  */
 356   init_stmts = NULL_TREE;
 357
 358   /* Loop through the parameter declarations, replacing each with an
 359      equivalent VAR_DECL, appropriately initialized.  */
 360   for (p = parms, a = args; p; a = TREE_CHAIN (a), p = TREE_CHAIN (p))
 361     {
 362       tree init_stmt;
 363       tree var;
 364
 365       /* Make an equivalent VAR_DECL.  */
 366       var = copy_decl_for_inlining (p, fn, VARRAY_TREE (id->fns, 0));
 367       /* Register the VAR_DECL as the equivalent for the PARM_DECL;
 368          that way, when the PARM_DECL is encountered, it will be
 369          automatically replaced by the VAR_DECL.  */
 370       splay_tree_insert (id->decl_map,
 371                          (splay_tree_key) p,
 372                          (splay_tree_value) var);
 373       /* Initialize this VAR_DECL from the equivalent argument.  If
 374          the argument is an object, created via a constructor or copy,
 375          this will not result in an extra copy: the TARGET_EXPR
 376          representing the argument will be bound to VAR, and the
 377          object will be constructed in VAR.  */
 378       init_stmt = build_min_nt (EXPR_STMT,
 379                                 build (INIT_EXPR, TREE_TYPE (p),
 380                                        var, TREE_VALUE (a)));
 381       /* Declare this new variable.  Note that we do this *after* the
 382          initialization because we are going to reverse all the
 383          initialization statements below.  */
 384       TREE_CHAIN (init_stmt) = build_min_nt (DECL_STMT, var);
 385       /* Add this initialization to the list.  */
 386       TREE_CHAIN (TREE_CHAIN (init_stmt)) = init_stmts;
 387       init_stmts = init_stmt;
 388     }
 389
 390   /* The initialization statements have been built up in reverse
 391      order.  Straighten them out now.  */
 392   return nreverse (init_stmts);
 393 }
 394
 395 /* Declare a return variable to replace the RESULT_DECL for the
 396    function we are calling.  An appropriate DECL_STMT is returned.
 397    The USE_STMT is filled in to contain a use of the declaration to
 398    indicate the return value of the function.  */
 399
 400 static tree
 401 declare_return_variable (id, use_stmt)
 402      struct inline_data *id;
 403      tree *use_stmt;
 404 {
 405   tree fn = VARRAY_TOP_TREE (id->fns);
 406   tree result = DECL_RESULT (fn);
 407   tree var;
 408
 409   /* We don't need to do anything for functions that don't return
 410      anything.  */
 411   if (!result || same_type_p (TYPE_MAIN_VARIANT (TREE_TYPE (result)),
 412                               void_type_node))
 413     {
 414       *use_stmt = NULL_TREE;
 415       return NULL_TREE;
 416     }
 417
 418   /* Make an appropriate copy.  */
 419   var = copy_decl_for_inlining (result, fn, VARRAY_TREE (id->fns, 0));
 420   /* Register the VAR_DECL as the equivalent for the RESULT_DECL; that
 421      way, when the RESULT_DECL is encountered, it will be
 422      automatically replaced by the VAR_DECL.  */
 423   splay_tree_insert (id->decl_map,
 424                      (splay_tree_key) result,
 425                      (splay_tree_value) var);
 426
 427   /* Build the USE_STMT.  */
 428   *use_stmt = build_min_nt (EXPR_STMT, var);
 429
 430   /* Build the declaration statement.  */
 431   return build_min_nt (DECL_STMT, var);
 432 }
 433
 434 /* Returns non-zero if FN is a function that can be inlined.  */
 435
 436 static int
 437 inlinable_function_p (fn, id)
 438      tree fn;
 439      inline_data *id;
 440 {
 441   int inlinable;
 442
 443   /* If we've already decided this function shouldn't be inlined,
 444      there's no need to check again.  */
 445   if (DECL_UNINLINABLE (fn))
 446     return 0;
 447
 448   /* Assume it is not inlinable.  */
 449   inlinable = 0;
 450
 451   /* If we're not inlining things, then nothing is inlinable.  */
 452   if (!flag_inline_trees)
 453     ;
 454   /* If the function was not declared `inline', then we don't inline
 455      it.  */
 456   else if (!DECL_INLINE (fn))
 457     ;
 458   /* If we don't have the function body available, we can't inline
 459      it.  */
 460   else if (!DECL_SAVED_TREE (fn))
 461     ;
 462   /* We can't inline varargs functions.  */
 463   else if (varargs_function_p (fn))
 464     ;
 465   /* All is well.  We can inline this function.  Traditionally, GCC
 466      has refused to inline functions using setjmp or alloca, or
 467      functions whose values are returned in a PARALLEL, and a few
 468      other such obscure conditions.  We are not equally constrained at
 469      the tree level.  */
 470   else
 471     inlinable = 1;
 472
 473   /* Squirrel away the result so that we don't have to check again.  */
 474   DECL_UNINLINABLE (fn) = !inlinable;
 475
 476   /* Don't do recursive inlining, either.  We don't record this in
 477      DECL_UNLINABLE; we may be able to inline this function later.  */
 478   if (inlinable)
 479     {
 480       size_t i;
 481
 482       for (i = 0; i < id->fns->elements_used; ++i)
 483         if (VARRAY_TREE (id->fns, i) == fn)
 484           inlinable = 0;
 485     }
 486
 487   /* We can inline a template instantiation only if it's fully
 488      instantiated.  */
 489   if (inlinable
 490       && DECL_TEMPLATE_INFO (fn)
 491       && TI_PENDING_TEMPLATE_FLAG (DECL_TEMPLATE_INFO (fn)))
 492     {
 493       fn = instantiate_decl (fn);
 494       inlinable = !TI_PENDING_TEMPLATE_FLAG (DECL_TEMPLATE_INFO (fn));
 495     }
 496
 497   /* Return the result.  */
 498   return inlinable;
 499 }
 500
 501 /* If *TP is a CALL_EXPR, replace it with its inline expansion.  */
 502
 503 static tree
 504 expand_call_inline (tp, walk_subtrees, data)
 505      tree *tp;
 506      int *walk_subtrees;
 507      void *data;
 508 {
 509   inline_data *id;
 510   tree t;
 511   tree expr;
 512   tree chain;
 513   tree fn;
 514   tree scope_stmt;
 515   tree use_stmt;
 516   tree arg_inits;
 517   splay_tree st;
 518
 519   /* See what we've got.  */
 520   id = (inline_data *) data;
 521   t = *tp;
 522
 523   /* Recurse, but letting recursive invocations know that we are
 524      inside the body of a TARGET_EXPR.  */
 525   if (TREE_CODE (*tp) == TARGET_EXPR)
 526     {
 527       int i, len = first_rtl_op (TARGET_EXPR);
 528
 529       /* We're walking our own subtrees.  */
 530       *walk_subtrees = 0;
 531
 532       /* Actually walk over them.  This loop is the body of
 533          walk_trees, omitting the case where the TARGET_EXPR
 534          itself is handled.  */
 535       for (i = 0; i < len; ++i)
 536         {
 537           if (i == 2)
 538             ++id->in_target_cleanup_p;
 539           walk_tree (&TREE_OPERAND (*tp, i), expand_call_inline, data);
 540           if (i == 2)
 541             --id->in_target_cleanup_p;
 542         }
 543
 544       return NULL_TREE;
 545     }
 546
 547   /* From here on, we're only interested in CALL_EXPRs.  */
 548   if (TREE_CODE (t) != CALL_EXPR)
 549     return NULL_TREE;
 550
 551   /* First, see if we can figure out what function is being called.
 552      If we cannot, then there is no hope of inlining the function.  */
 553   fn = get_callee_fndecl (t);
 554   if (!fn)
 555     return NULL_TREE;
 556
 557   /* Don't try to inline functions that are not well-suited to
 558      inlining.  */
 559   if (!inlinable_function_p (fn, id))
 560     return NULL_TREE;
 561
 562   /* Build a statement-expression containing code to initialize the
 563      arguments, the actual inline expansion of the body, and a label
 564      for the return statements within the function to jump to.  The
 565      type of the statement expression is the return type of the
 566      function call.  */
 567   expr = build_min (STMT_EXPR, TREE_TYPE (TREE_TYPE (fn)), NULL_TREE);
 568
 569   /* Local declarations will be replaced by their equivalents in this
 570      map.  */
 571   st = id->decl_map;
 572   id->decl_map = splay_tree_new (splay_tree_compare_pointers,
 573                                  NULL, NULL);
 574
 575   /* Initialize the parameters.  */
 576   arg_inits = initialize_inlined_parameters (id, TREE_OPERAND (t, 1), fn);
 577   /* Expand any inlined calls in the initializers.  Do this before we
 578      push FN on the stack of functions we are inlining; we want to
 579      inline calls to FN that appear in the initializers for the
 580      parameters.  */
 581   expand_calls_inline (&arg_inits, id);
 582   /* And add them to the tree.  */
 583   STMT_EXPR_STMT (expr) = chainon (STMT_EXPR_STMT (expr), arg_inits);
 584
 585   /* Record the function we are about to inline so that we can avoid
 586      recursing into it.  */
 587   VARRAY_PUSH_TREE (id->fns, fn);
 588
 589   /* Return statements in the function body will be replaced by jumps
 590      to the RET_LABEL.  */
 591   id->ret_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
 592   DECL_CONTEXT (id->ret_label) = VARRAY_TREE (id->fns, 0);
 593
 594   /* Create a block to put the parameters in.  We have to do this
 595      after the parameters have been remapped because remapping
 596      parameters is different from remapping ordinary variables.  */
 597   scope_stmt = build_min_nt (SCOPE_STMT, DECL_INITIAL (fn));
 598   SCOPE_BEGIN_P (scope_stmt) = 1;
 599   SCOPE_NO_CLEANUPS_P (scope_stmt) = 1;
 600   remap_block (scope_stmt, DECL_ARGUMENTS (fn), id);
 601   TREE_CHAIN (scope_stmt) = STMT_EXPR_STMT (expr);
 602   STMT_EXPR_STMT (expr) = scope_stmt;
 603
 604   /* Tell the debugging backends that this block represents the
 605      outermost scope of the inlined function.  */
 606   if (SCOPE_STMT_BLOCK (scope_stmt))
 607     BLOCK_ABSTRACT_ORIGIN (SCOPE_STMT_BLOCK (scope_stmt)) = DECL_ORIGIN (fn);
 608
 609   /* Declare the return variable for the function.  */
 610   STMT_EXPR_STMT (expr)
 611     = chainon (STMT_EXPR_STMT (expr),
 612                declare_return_variable (id, &use_stmt));
 613
 614   /* After we've initialized the parameters, we insert the body of the
 615      function itself.  */
 616   STMT_EXPR_STMT (expr)
 617     = chainon (STMT_EXPR_STMT (expr), copy_body (id));
 618
 619   /* Close the block for the parameters.  */
 620   scope_stmt = build_min_nt (SCOPE_STMT, DECL_INITIAL (fn));
 621   SCOPE_NO_CLEANUPS_P (scope_stmt) = 1;
 622   my_friendly_assert (DECL_INITIAL (fn)
 623                       && TREE_CODE (DECL_INITIAL (fn)) == BLOCK,
 624                       19991203);
 625   remap_block (scope_stmt, NULL_TREE, id);
 626   STMT_EXPR_STMT (expr)
 627     = chainon (STMT_EXPR_STMT (expr), scope_stmt);
 628
 629   /* Finally, mention the returned value so that the value of the
 630      statement-expression is the returned value of the function.  */
 631   STMT_EXPR_STMT (expr) = chainon (STMT_EXPR_STMT (expr), use_stmt);
 632
 633   /* Clean up.  */
 634   splay_tree_delete (id->decl_map);
 635   id->decl_map = st;
 636
 637   /* After the body of the function comes the RET_LABEL.  */
 638   STMT_EXPR_STMT (expr)
 639     = chainon (STMT_EXPR_STMT (expr),
 640                build_min_nt (LABEL_STMT, id->ret_label));
 641
 642   /* The new expression has side-effects if the old one did.  */
 643   TREE_SIDE_EFFECTS (expr) = TREE_SIDE_EFFECTS (t);
 644
 645   /* Replace the call by the inlined body.  Wrap it in an
 646      EXPR_WITH_FILE_LOCATION so that we'll get debugging line notes
 647      pointing to the right place.  */
 648   chain = TREE_CHAIN (*tp);
 649   *tp = build_expr_wfl (expr, DECL_SOURCE_FILE (fn), DECL_SOURCE_LINE (fn),
 650                         /*col=*/0);
 651   EXPR_WFL_EMIT_LINE_NOTE (*tp) = 1;
 652   TREE_CHAIN (*tp) = chain;
 653
 654   /* If the value of the new expression is ignored, that's OK.  We
 655      don't warn about this for CALL_EXPRs, so we shouldn't warn about
 656      the equivalent inlined version either.  */
 657   TREE_USED (*tp) = 1;
 658
 659   /* Recurse into the body of the just inlined function.  */
 660   expand_calls_inline (tp, id);
 661   VARRAY_POP (id->fns);
 662
 663   /* Don't walk into subtrees.  We've already handled them above.  */
 664   *walk_subtrees = 0;
 665
 666   /* Keep iterating.  */
 667   return NULL_TREE;
 668 }
 669
 670 /* Walk over the entire tree *TP, replacing CALL_EXPRs with inline
 671    expansions as appropriate.  */
 672
 673 static void
 674 expand_calls_inline (tp, id)
 675      tree *tp;
 676      inline_data *id;
 677 {
 678   /* Search through *TP, replacing all calls to inline functions by
 679      appropriate equivalents.  */
 680   walk_tree (tp, expand_call_inline, id);
 681 }
 682
 683 /* Optimize the body of FN.  */
 684
 685 void
 686 optimize_function (fn)
 687      tree fn;
 688 {
 689   /* Expand calls to inline functions.  */
 690   if (flag_inline_trees)
 691     {
 692       inline_data id;
 693       tree prev_fn;
 694       struct saved_scope *s;
 695
 696       /* Clear out ID.  */
 697       memset (&id, 0, sizeof (id));
 698
 699       /* Don't allow recursion into FN.  */
 700       VARRAY_TREE_INIT (id.fns, 32, "fns");
 701       VARRAY_PUSH_TREE (id.fns, fn);
 702       /* Or any functions that aren't finished yet.  */
 703       prev_fn = NULL_TREE;
 704       if (current_function_decl)
 705         {
 706           VARRAY_PUSH_TREE (id.fns, current_function_decl);
 707           prev_fn = current_function_decl;
 708         }
 709       for (s = scope_chain; s; s = s->prev)
 710         if (s->function_decl && s->function_decl != prev_fn)
 711           {
 712             VARRAY_PUSH_TREE (id.fns, s->function_decl);
 713             prev_fn = s->function_decl;
 714           }
 715
 716       /* Replace all calls to inline functions with the bodies of those
 717          functions.  */
 718       expand_calls_inline (&DECL_SAVED_TREE (fn), &id);
 719
 720       /* Clean up.  */
 721       VARRAY_FREE (id.fns);
 722     }
 723 }
 724
 725 /* Called from calls_setjmp_p via walk_tree.  */
 726
 727 static tree
 728 calls_setjmp_r (tp, walk_subtrees, data)
 729      tree *tp;
 730      int *walk_subtrees ATTRIBUTE_UNUSED;
 731      void *data ATTRIBUTE_UNUSED;
 732 {
 733   int setjmp_p;
 734   int longjmp_p;
 735   int malloc_p;
 736   int alloca_p;
 737
 738   /* We're only interested in FUNCTION_DECLS.  */
 739   if (TREE_CODE (*tp) != FUNCTION_DECL)
 740     return NULL_TREE;
 741
 742   special_function_p (*tp, &setjmp_p, &longjmp_p, &malloc_p, &alloca_p);
 743
 744   return setjmp_p ? *tp : NULL_TREE;
 745 }
 746
 747 /* Returns non-zero if FN calls `setjmp' or some other function that
 748    can return more than once.  This function is conservative; it may
 749    occasionally return a non-zero value even when FN does not actually
 750    call `setjmp'.  */
 751
 752 int
 753 calls_setjmp_p (fn)
 754      tree fn;
 755 {
 756   return (walk_tree (&DECL_SAVED_TREE (fn), calls_setjmp_r, NULL)
 757           != NULL_TREE);
 758 }
 759