--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/c-gimplify.c	Fri Jul 17 14:47:48 2009 +0900
@@ -0,0 +1,320 @@
+/* Tree lowering pass.  This pass gimplifies the tree representation built
+   by the C-based front ends.  The structure of gimplified, or
+   language-independent, trees is dictated by the grammar described in this
+   file.
+   Copyright (C) 2002, 2003, 2004, 2005, 2007, 2008
+   Free Software Foundation, Inc.
+   Lowering of expressions contributed by Sebastian Pop <s.pop@laposte.net>
+   Re-written to support lowering of whole function trees, documentation
+   and miscellaneous cleanups by Diego Novillo <dnovillo@redhat.com>
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "tree.h"
+#include "varray.h"
+#include "c-tree.h"
+#include "c-common.h"
+#include "gimple.h"
+#include "hard-reg-set.h"
+#include "basic-block.h"
+#include "tree-flow.h"
+#include "tree-inline.h"
+#include "diagnostic.h"
+#include "langhooks.h"
+#include "langhooks-def.h"
+#include "flags.h"
+#include "rtl.h"
+#include "toplev.h"
+#include "tree-dump.h"
+#include "c-pretty-print.h"
+#include "cgraph.h"
+
+
+/*  The gimplification pass converts the language-dependent trees
+    (ld-trees) emitted by the parser into language-independent trees
+    (li-trees) that are the target of SSA analysis and transformations.
+
+    Language-independent trees are based on the SIMPLE intermediate
+    representation used in the McCAT compiler framework:
+
+    "Designing the McCAT Compiler Based on a Family of Structured
+    Intermediate Representations,"
+    L. Hendren, C. Donawa, M. Emami, G. Gao, Justiani, and B. Sridharan,
+    Proceedings of the 5th International Workshop on Languages and
+    Compilers for Parallel Computing, no. 757 in Lecture Notes in
+    Computer Science, New Haven, Connecticut, pp. 406-420,
+    Springer-Verlag, August 3-5, 1992.
+
+    http://www-acaps.cs.mcgill.ca/info/McCAT/McCAT.html
+
+    Basically, we walk down gimplifying the nodes that we encounter.  As we
+    walk back up, we check that they fit our constraints, and copy them
+    into temporaries if not.  */
+
+/* Gimplification of statement trees.  */
+
+/* Convert the tree representation of FNDECL from C frontend trees to
+   GENERIC.  */
+
+void
+c_genericize (tree fndecl)
+{
+  FILE *dump_orig;
+  int local_dump_flags;
+  struct cgraph_node *cgn;
+
+  /* Dump the C-specific tree IR.  */
+  dump_orig = dump_begin (TDI_original, &local_dump_flags);
+  if (dump_orig)
+    {
+      fprintf (dump_orig, "\n;; Function %s",
+	       lang_hooks.decl_printable_name (fndecl, 2));
+      fprintf (dump_orig, " (%s)\n",
+	       (!DECL_ASSEMBLER_NAME_SET_P (fndecl) ? "null"
+		: IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (fndecl))));
+      fprintf (dump_orig, ";; enabled by -%s\n", dump_flag_name (TDI_original));
+      fprintf (dump_orig, "\n");
+
+      if (local_dump_flags & TDF_RAW)
+	dump_node (DECL_SAVED_TREE (fndecl),
+		   TDF_SLIM | local_dump_flags, dump_orig);
+      else
+	print_c_tree (dump_orig, DECL_SAVED_TREE (fndecl));
+      fprintf (dump_orig, "\n");
+
+      dump_end (TDI_original, dump_orig);
+    }
+
+  /* Go ahead and gimplify for now.  */
+  gimplify_function_tree (fndecl);
+
+  dump_function (TDI_generic, fndecl);
+
+  /* Genericize all nested functions now.  We do things in this order so
+     that items like VLA sizes are expanded properly in the context of
+     the correct function.  */
+  cgn = cgraph_node (fndecl);
+  for (cgn = cgn->nested; cgn ; cgn = cgn->next_nested)
+    c_genericize (cgn->decl);
+}
+
+static void
+add_block_to_enclosing (tree block)
+{
+  unsigned i;
+  tree enclosing;
+  gimple bind;
+  VEC(gimple, heap) *stack = gimple_bind_expr_stack ();
+
+  for (i = 0; VEC_iterate (gimple, stack, i, bind); i++)
+    if (gimple_bind_block (bind))
+      break;
+
+  enclosing = gimple_bind_block (bind);
+  BLOCK_SUBBLOCKS (enclosing) = chainon (BLOCK_SUBBLOCKS (enclosing), block);
+}
+
+/* Genericize a scope by creating a new BIND_EXPR.
+   BLOCK is either a BLOCK representing the scope or a chain of _DECLs.
+     In the latter case, we need to create a new BLOCK and add it to the
+     BLOCK_SUBBLOCKS of the enclosing block.
+   BODY is a chain of C _STMT nodes for the contents of the scope, to be
+     genericized.  */
+
+tree
+c_build_bind_expr (tree block, tree body)
+{
+  tree decls, bind;
+
+  if (block == NULL_TREE)
+    decls = NULL_TREE;
+  else if (TREE_CODE (block) == BLOCK)
+    decls = BLOCK_VARS (block);
+  else
+    {
+      decls = block;
+      if (DECL_ARTIFICIAL (decls))
+	block = NULL_TREE;
+      else
+	{
+	  block = make_node (BLOCK);
+	  BLOCK_VARS (block) = decls;
+	  add_block_to_enclosing (block);
+	}
+    }
+
+  if (!body)
+    body = build_empty_stmt ();
+  if (decls || block)
+    {
+      bind = build3 (BIND_EXPR, void_type_node, decls, body, block);
+      TREE_SIDE_EFFECTS (bind) = 1;
+    }
+  else
+    bind = body;
+
+  return bind;
+}
+
+/* Gimplification of expression trees.  */
+
+/* Gimplify a C99 compound literal expression.  This just means adding
+   the DECL_EXPR before the current statement and using its anonymous
+   decl instead.  */
+
+static enum gimplify_status
+gimplify_compound_literal_expr (tree *expr_p, gimple_seq *pre_p)
+{
+  tree decl_s = COMPOUND_LITERAL_EXPR_DECL_STMT (*expr_p);
+  tree decl = DECL_EXPR_DECL (decl_s);
+  /* Mark the decl as addressable if the compound literal
+     expression is addressable now, otherwise it is marked too late
+     after we gimplify the initialization expression.  */
+  if (TREE_ADDRESSABLE (*expr_p))
+    TREE_ADDRESSABLE (decl) = 1;
+
+  /* Preliminarily mark non-addressed complex variables as eligible
+     for promotion to gimple registers.  We'll transform their uses
+     as we find them.  */
+  if ((TREE_CODE (TREE_TYPE (decl)) == COMPLEX_TYPE
+       || TREE_CODE (TREE_TYPE (decl)) == VECTOR_TYPE)
+      && !TREE_THIS_VOLATILE (decl)
+      && !needs_to_live_in_memory (decl))
+    DECL_GIMPLE_REG_P (decl) = 1;
+
+  /* This decl isn't mentioned in the enclosing block, so add it to the
+     list of temps.  FIXME it seems a bit of a kludge to say that
+     anonymous artificial vars aren't pushed, but everything else is.  */
+  if (DECL_NAME (decl) == NULL_TREE && !DECL_SEEN_IN_BIND_EXPR_P (decl))
+    gimple_add_tmp_var (decl);
+
+  gimplify_and_add (decl_s, pre_p);
+  *expr_p = decl;
+  return GS_OK;
+}
+
+/* Optimize embedded COMPOUND_LITERAL_EXPRs within a CONSTRUCTOR,
+   return a new CONSTRUCTOR if something changed.  */
+
+static tree
+optimize_compound_literals_in_ctor (tree orig_ctor)
+{
+  tree ctor = orig_ctor;
+  VEC(constructor_elt,gc) *elts = CONSTRUCTOR_ELTS (ctor);
+  unsigned int idx, num = VEC_length (constructor_elt, elts);
+
+  for (idx = 0; idx < num; idx++)
+    {
+      tree value = VEC_index (constructor_elt, elts, idx)->value;
+      tree newval = value;
+      if (TREE_CODE (value) == CONSTRUCTOR)
+	newval = optimize_compound_literals_in_ctor (value);
+      else if (TREE_CODE (value) == COMPOUND_LITERAL_EXPR)
+	{
+	  tree decl_s = COMPOUND_LITERAL_EXPR_DECL_STMT (value);
+	  tree decl = DECL_EXPR_DECL (decl_s);
+	  tree init = DECL_INITIAL (decl);
+
+	  if (!TREE_ADDRESSABLE (value)
+	      && !TREE_ADDRESSABLE (decl)
+	      && init)
+	    newval = init;
+	}
+      if (newval == value)
+	continue;
+
+      if (ctor == orig_ctor)
+	{
+	  ctor = copy_node (orig_ctor);
+	  CONSTRUCTOR_ELTS (ctor) = VEC_copy (constructor_elt, gc, elts);
+	  elts = CONSTRUCTOR_ELTS (ctor);
+	}
+      VEC_index (constructor_elt, elts, idx)->value = newval;
+    }
+  return ctor;
+}
+
+/* Do C-specific gimplification on *EXPR_P.  PRE_P and POST_P are as in
+   gimplify_expr.  */
+
+int
+c_gimplify_expr (tree *expr_p, gimple_seq *pre_p,
+		 gimple_seq *post_p ATTRIBUTE_UNUSED)
+{
+  enum tree_code code = TREE_CODE (*expr_p);
+
+  switch (code)
+    {
+    case DECL_EXPR:
+      /* This is handled mostly by gimplify.c, but we have to deal with
+	 not warning about int x = x; as it is a GCC extension to turn off
+	 this warning but only if warn_init_self is zero.  */
+      if (TREE_CODE (DECL_EXPR_DECL (*expr_p)) == VAR_DECL
+	  && !DECL_EXTERNAL (DECL_EXPR_DECL (*expr_p))
+	  && !TREE_STATIC (DECL_EXPR_DECL (*expr_p))
+	  && (DECL_INITIAL (DECL_EXPR_DECL (*expr_p))
+	      == DECL_EXPR_DECL (*expr_p))
+	  && !warn_init_self)
+	TREE_NO_WARNING (DECL_EXPR_DECL (*expr_p)) = 1;
+      return GS_UNHANDLED;
+
+    case COMPOUND_LITERAL_EXPR:
+      return gimplify_compound_literal_expr (expr_p, pre_p);
+
+    case INIT_EXPR:
+    case MODIFY_EXPR:
+      if (TREE_CODE (TREE_OPERAND (*expr_p, 1)) == COMPOUND_LITERAL_EXPR)
+	{
+	  tree complit = TREE_OPERAND (*expr_p, 1);
+	  tree decl_s = COMPOUND_LITERAL_EXPR_DECL_STMT (complit);
+	  tree decl = DECL_EXPR_DECL (decl_s);
+	  tree init = DECL_INITIAL (decl);
+
+	  /* struct T x = (struct T) { 0, 1, 2 } can be optimized
+	     into struct T x = { 0, 1, 2 } if the address of the
+	     compound literal has never been taken.  */
+	  if (!TREE_ADDRESSABLE (complit)
+	      && !TREE_ADDRESSABLE (decl)
+	      && init)
+	    {
+	      *expr_p = copy_node (*expr_p);
+	      TREE_OPERAND (*expr_p, 1) = init;
+	      return GS_OK;
+	    }
+	}
+      else if (TREE_CODE (TREE_OPERAND (*expr_p, 1)) == CONSTRUCTOR)
+	{
+	  tree ctor
+	    = optimize_compound_literals_in_ctor (TREE_OPERAND (*expr_p, 1));
+
+	  if (ctor != TREE_OPERAND (*expr_p, 1))
+	    {
+	      *expr_p = copy_node (*expr_p);
+	      TREE_OPERAND (*expr_p, 1) = ctor;
+	      return GS_OK;
+	    }
+	}
+      return GS_UNHANDLED;
+
+    default:
+      return GS_UNHANDLED;
+    }
+}