gcc/cp/optimize.c

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