gcc/java/java-gimplify.c

   1 /* Java(TM) language-specific gimplification routines.
   2    Copyright (C) 2003, 2004, 2006, 2007, 2007, 2008
   3    Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 3, or (at your option)
  10 any later version.
  11
  12 GCC is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.
  20
  21 Java and all Java-based marks are trademarks or registered trademarks
  22 of Sun Microsystems, Inc. in the United States and other countries.
  23 The Free Software Foundation is independent of Sun Microsystems, Inc.  */
  24
  25 #include "config.h"
  26 #include "system.h"
  27 #include "coretypes.h"
  28 #include "tm.h"
  29 #include "tree.h"
  30 #include "java-tree.h"
  31 #include "tree-dump.h"
  32 #include "gimple.h"
  33 #include "toplev.h"
  34
  35 static tree java_gimplify_block (tree);
  36 static enum gimplify_status java_gimplify_modify_expr (tree *);
  37 static enum gimplify_status java_gimplify_self_mod_expr (tree *, gimple_seq *,
  38                                                          gimple_seq *);
  39
  40 static void dump_java_tree (enum tree_dump_index, tree);
  41
  42 /* Convert a Java tree to GENERIC.  */
  43
  44 void
  45 java_genericize (tree fndecl)
  46 {
  47   dump_java_tree (TDI_original, fndecl);
  48
  49   /* Genericize with the gimplifier.  */
  50   gimplify_function_tree (fndecl);
  51
  52   dump_function (TDI_generic, fndecl);
  53 }
  54
  55 /* Gimplify a Java tree.  */
  56
  57 int
  58 java_gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
  59 {
  60   enum tree_code code = TREE_CODE (*expr_p);
  61
  62   switch (code)
  63     {
  64     case BLOCK:
  65       *expr_p = java_gimplify_block (*expr_p);
  66       break;
  67
  68     case VAR_DECL:
  69       *expr_p = java_replace_reference (*expr_p, /* want_lvalue */ false);
  70       return GS_UNHANDLED;
  71
  72     case MODIFY_EXPR:
  73       return java_gimplify_modify_expr (expr_p);
  74
  75     case SAVE_EXPR:
  76       /* Note that we can see <save_expr NULL> if the save_expr was
  77          already handled by gimplify_save_expr.  */
  78       if (TREE_OPERAND (*expr_p, 0) != NULL_TREE
  79           && TREE_CODE (TREE_OPERAND (*expr_p, 0)) == VAR_DECL)
  80         TREE_OPERAND (*expr_p, 0)
  81           = java_replace_reference (TREE_OPERAND (*expr_p, 0),
  82                                /* want_lvalue */ false);
  83       return GS_UNHANDLED;
  84
  85     case POSTINCREMENT_EXPR:
  86     case POSTDECREMENT_EXPR:
  87     case PREINCREMENT_EXPR:
  88     case PREDECREMENT_EXPR:
  89       return java_gimplify_self_mod_expr (expr_p, pre_p, post_p);
  90
  91     /* These should already be lowered before we get here.  */
  92     case URSHIFT_EXPR:
  93     case COMPARE_EXPR:
  94     case COMPARE_L_EXPR:
  95     case COMPARE_G_EXPR:
  96       gcc_unreachable ();
  97
  98     default:
  99       return GS_UNHANDLED;
 100     }
 101
 102   return GS_OK;
 103 }
 104
 105 static enum gimplify_status
 106 java_gimplify_modify_expr (tree *modify_expr_p)
 107 {
 108   tree modify_expr = *modify_expr_p;
 109   tree lhs = TREE_OPERAND (modify_expr, 0);
 110   tree rhs = TREE_OPERAND (modify_expr, 1);
 111   tree lhs_type = TREE_TYPE (lhs);
 112
 113   /* This is specific to the bytecode compiler.  If a variable has
 114      LOCAL_SLOT_P set, replace an assignment to it with an assignment
 115      to the corresponding variable that holds all its aliases.  */
 116   if (TREE_CODE (lhs) == VAR_DECL
 117       && DECL_LANG_SPECIFIC (lhs)
 118       && LOCAL_SLOT_P (lhs)
 119       && TREE_CODE (lhs_type) == POINTER_TYPE)
 120     {
 121       tree new_lhs = java_replace_reference (lhs, /* want_lvalue */ true);
 122       tree new_rhs = build1 (NOP_EXPR, TREE_TYPE (new_lhs), rhs);
 123       modify_expr = build2 (MODIFY_EXPR, TREE_TYPE (new_lhs),
 124                             new_lhs, new_rhs);
 125       modify_expr = build1 (NOP_EXPR, lhs_type, modify_expr);
 126     }
 127   else if (lhs_type != TREE_TYPE (rhs))
 128     /* Fix up type mismatches to make legal GIMPLE.  These are
 129        generated in several places, in particular null pointer
 130        assignment and subclass assignment.  */
 131     TREE_OPERAND (modify_expr, 1) = convert (lhs_type, rhs);
 132
 133   *modify_expr_p = modify_expr;
 134   return GS_UNHANDLED;
 135 }
 136
 137 /*  Special case handling for volatiles: we need to generate a barrier
 138     between the reading and the writing.  */
 139
 140 static enum gimplify_status
 141 java_gimplify_self_mod_expr (tree *expr_p, gimple_seq *pre_p ATTRIBUTE_UNUSED,
 142                              gimple_seq *post_p ATTRIBUTE_UNUSED)
 143 {
 144   tree lhs = TREE_OPERAND (*expr_p, 0);
 145
 146   if (TREE_CODE (lhs) == COMPONENT_REF
 147       && TREE_THIS_VOLATILE (TREE_OPERAND (lhs, 1)))
 148     TREE_THIS_VOLATILE (lhs) = 1;
 149
 150   return GS_UNHANDLED;
 151 }
 152
 153
 154 /* Gimplify BLOCK into a BIND_EXPR.  */
 155
 156 static tree
 157 java_gimplify_block (tree java_block)
 158 {
 159   tree decls = BLOCK_VARS (java_block);
 160   tree body = BLOCK_EXPR_BODY (java_block);
 161   gimple outer = gimple_current_bind_expr ();
 162   tree block;
 163
 164   /* Don't bother with empty blocks.  */
 165   if (! body)
 166     return build_empty_stmt ();
 167
 168   if (IS_EMPTY_STMT (body))
 169     return body;
 170
 171   /* Make a proper block.  Java blocks are unsuitable for BIND_EXPR
 172      because they use BLOCK_SUBBLOCKS for another purpose.  */
 173   block = make_node (BLOCK);
 174   BLOCK_VARS (block) = decls;
 175
 176   /* The TREE_USED flag on a block determines whether the debug output
 177      routines generate info for the variables in that block.  */
 178   TREE_USED (block) = 1;
 179
 180   if (outer != NULL)
 181     {
 182       tree b = gimple_bind_block (outer);
 183       BLOCK_SUBBLOCKS (b) = chainon (BLOCK_SUBBLOCKS (b), block);
 184     }
 185   BLOCK_EXPR_BODY (java_block) = NULL_TREE;
 186
 187   return build3 (BIND_EXPR, TREE_TYPE (java_block), decls, body, block);
 188 }
 189
 190 /* Dump a tree of some kind.  This is a convenience wrapper for the
 191    dump_* functions in tree-dump.c.  */
 192 static void
 193 dump_java_tree (enum tree_dump_index phase, tree t)
 194 {
 195   FILE *stream;
 196   int flags;
 197
 198   stream = dump_begin (phase, &flags);
 199   flags |= TDF_SLIM;
 200   if (stream)
 201     {
 202       dump_node (t, flags, stream);
 203       dump_end (phase, stream);
 204     }
 205 }