gcc/java/java-gimplify.c

   1 /* Java(TM) language-specific gimplification routines.
   2    Copyright (C) 2003-2013 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
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 3, or (at your option)
   9 any later version.
  10
  11 GCC is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.
  19
  20 Java and all Java-based marks are trademarks or registered trademarks
  21 of Sun Microsystems, Inc. in the United States and other countries.
  22 The Free Software Foundation is independent of Sun Microsystems, Inc.  */
  23
  24 #include "config.h"
  25 #include "system.h"
  26 #include "coretypes.h"
  27 #include "tree.h"
  28 #include "java-tree.h"
  29 #include "dumpfile.h"
  30 #include "gimple.h"
  31
  32 static tree java_gimplify_block (tree);
  33 static enum gimplify_status java_gimplify_modify_expr (tree *);
  34 static enum gimplify_status java_gimplify_self_mod_expr (tree *, gimple_seq *,
  35                                                          gimple_seq *);
  36
  37 static void dump_java_tree (enum tree_dump_index, tree);
  38
  39 /* Convert a Java tree to GENERIC.  */
  40
  41 void
  42 java_genericize (tree fndecl)
  43 {
  44   walk_tree (&DECL_SAVED_TREE (fndecl), java_replace_references, NULL, NULL);
  45   dump_java_tree (TDI_original, fndecl);
  46 }
  47
  48 /* Gimplify a Java tree.  */
  49
  50 int
  51 java_gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
  52 {
  53   enum tree_code code = TREE_CODE (*expr_p);
  54
  55   switch (code)
  56     {
  57     case BLOCK:
  58       *expr_p = java_gimplify_block (*expr_p);
  59       break;
  60
  61     case MODIFY_EXPR:
  62       return java_gimplify_modify_expr (expr_p);
  63
  64     case POSTINCREMENT_EXPR:
  65     case POSTDECREMENT_EXPR:
  66     case PREINCREMENT_EXPR:
  67     case PREDECREMENT_EXPR:
  68       return java_gimplify_self_mod_expr (expr_p, pre_p, post_p);
  69
  70     /* These should already be lowered before we get here.  */
  71     case URSHIFT_EXPR:
  72     case COMPARE_EXPR:
  73     case COMPARE_L_EXPR:
  74     case COMPARE_G_EXPR:
  75       gcc_unreachable ();
  76
  77     default:
  78       return GS_UNHANDLED;
  79     }
  80
  81   return GS_OK;
  82 }
  83
  84 static enum gimplify_status
  85 java_gimplify_modify_expr (tree *modify_expr_p)
  86 {
  87   tree modify_expr = *modify_expr_p;
  88   tree lhs = TREE_OPERAND (modify_expr, 0);
  89   tree rhs = TREE_OPERAND (modify_expr, 1);
  90   tree lhs_type = TREE_TYPE (lhs);
  91
  92   if (lhs_type != TREE_TYPE (rhs))
  93     /* Fix up type mismatches to make legal GIMPLE.  These are
  94        generated in several places, in particular null pointer
  95        assignment and subclass assignment.  */
  96     TREE_OPERAND (modify_expr, 1) = convert (lhs_type, rhs);
  97
  98   return GS_UNHANDLED;
  99 }
 100
 101 /*  Special case handling for volatiles: we need to generate a barrier
 102     between the reading and the writing.  */
 103
 104 static enum gimplify_status
 105 java_gimplify_self_mod_expr (tree *expr_p, gimple_seq *pre_p ATTRIBUTE_UNUSED,
 106                              gimple_seq *post_p ATTRIBUTE_UNUSED)
 107 {
 108   tree lhs = TREE_OPERAND (*expr_p, 0);
 109
 110   if (TREE_CODE (lhs) == COMPONENT_REF
 111       && TREE_THIS_VOLATILE (TREE_OPERAND (lhs, 1)))
 112     TREE_THIS_VOLATILE (lhs) = 1;
 113
 114   return GS_UNHANDLED;
 115 }
 116
 117
 118 /* Gimplify BLOCK into a BIND_EXPR.  */
 119
 120 static tree
 121 java_gimplify_block (tree java_block)
 122 {
 123   tree decls = BLOCK_VARS (java_block);
 124   tree body = BLOCK_EXPR_BODY (java_block);
 125   gimple outer = gimple_current_bind_expr ();
 126   tree block;
 127
 128   /* Don't bother with empty blocks.  */
 129   if (! body)
 130     return build_empty_stmt (input_location);
 131
 132   if (IS_EMPTY_STMT (body))
 133     return body;
 134
 135   /* Make a proper block.  Java blocks are unsuitable for BIND_EXPR
 136      because they use BLOCK_SUBBLOCKS for another purpose.  */
 137   block = make_node (BLOCK);
 138   BLOCK_VARS (block) = decls;
 139
 140   /* The TREE_USED flag on a block determines whether the debug output
 141      routines generate info for the variables in that block.  */
 142   TREE_USED (block) = 1;
 143
 144   if (outer != NULL)
 145     {
 146       tree b = gimple_bind_block (outer);
 147       BLOCK_SUBBLOCKS (b) = chainon (BLOCK_SUBBLOCKS (b), block);
 148     }
 149   BLOCK_EXPR_BODY (java_block) = NULL_TREE;
 150
 151   return build3 (BIND_EXPR, TREE_TYPE (java_block), decls, body, block);
 152 }
 153
 154 /* Dump a tree of some kind.  This is a convenience wrapper for the
 155    dump_* functions in tree-dump.c.  */
 156 static void
 157 dump_java_tree (enum tree_dump_index phase, tree t)
 158 {
 159   FILE *stream;
 160   int flags;
 161
 162   stream = dump_begin (phase, &flags);
 163   flags |= TDF_SLIM;
 164   if (stream)
 165     {
 166       dump_node (t, flags, stream);
 167       dump_end (phase, stream);
 168     }
 169 }