gcc/java/java-gimplify.c

   1 /* Java(TM) language-specific gimplification routines.
   2    Copyright (C) 2003-2016 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 "function.h"
  28 #include "basic-block.h"
  29 #include "tree.h"
  30 #include "gimple.h"
  31 #include "java-tree.h"
  32 #include "dumpfile.h"
  33 #include "gimplify.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   walk_tree (&DECL_SAVED_TREE (fndecl), java_replace_references, NULL, NULL);
  48   dump_java_tree (TDI_original, fndecl);
  49 }
  50
  51 /* Gimplify a Java tree.  */
  52
  53 int
  54 java_gimplify_expr (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p)
  55 {
  56   enum tree_code code = TREE_CODE (*expr_p);
  57
  58   switch (code)
  59     {
  60     case BLOCK:
  61       *expr_p = java_gimplify_block (*expr_p);
  62       break;
  63
  64     case MODIFY_EXPR:
  65       return java_gimplify_modify_expr (expr_p);
  66
  67     case POSTINCREMENT_EXPR:
  68     case POSTDECREMENT_EXPR:
  69     case PREINCREMENT_EXPR:
  70     case PREDECREMENT_EXPR:
  71       return java_gimplify_self_mod_expr (expr_p, pre_p, post_p);
  72
  73     /* These should already be lowered before we get here.  */
  74     case URSHIFT_EXPR:
  75     case COMPARE_EXPR:
  76     case COMPARE_L_EXPR:
  77     case COMPARE_G_EXPR:
  78       gcc_unreachable ();
  79
  80     default:
  81       return GS_UNHANDLED;
  82     }
  83
  84   return GS_OK;
  85 }
  86
  87 static enum gimplify_status
  88 java_gimplify_modify_expr (tree *modify_expr_p)
  89 {
  90   tree modify_expr = *modify_expr_p;
  91   tree lhs = TREE_OPERAND (modify_expr, 0);
  92   tree rhs = TREE_OPERAND (modify_expr, 1);
  93   tree lhs_type = TREE_TYPE (lhs);
  94
  95   if (lhs_type != TREE_TYPE (rhs))
  96     /* Fix up type mismatches to make legal GIMPLE.  These are
  97        generated in several places, in particular null pointer
  98        assignment and subclass assignment.  */
  99     TREE_OPERAND (modify_expr, 1) = convert (lhs_type, rhs);
 100
 101   return GS_UNHANDLED;
 102 }
 103
 104 /*  Special case handling for volatiles: we need to generate a barrier
 105     between the reading and the writing.  */
 106
 107 static enum gimplify_status
 108 java_gimplify_self_mod_expr (tree *expr_p, gimple_seq *pre_p ATTRIBUTE_UNUSED,
 109                              gimple_seq *post_p ATTRIBUTE_UNUSED)
 110 {
 111   tree lhs = TREE_OPERAND (*expr_p, 0);
 112
 113   if (TREE_CODE (lhs) == COMPONENT_REF
 114       && TREE_THIS_VOLATILE (TREE_OPERAND (lhs, 1)))
 115     TREE_THIS_VOLATILE (lhs) = 1;
 116
 117   return GS_UNHANDLED;
 118 }
 119
 120
 121 /* Gimplify BLOCK into a BIND_EXPR.  */
 122
 123 static tree
 124 java_gimplify_block (tree java_block)
 125 {
 126   tree decls = BLOCK_VARS (java_block);
 127   tree body = BLOCK_EXPR_BODY (java_block);
 128   gbind *outer = gimple_current_bind_expr ();
 129   tree block;
 130
 131   /* Don't bother with empty blocks.  */
 132   if (! body)
 133     return build_empty_stmt (input_location);
 134
 135   if (IS_EMPTY_STMT (body))
 136     return body;
 137
 138   /* Make a proper block.  Java blocks are unsuitable for BIND_EXPR
 139      because they use BLOCK_SUBBLOCKS for another purpose.  */
 140   block = make_node (BLOCK);
 141   BLOCK_VARS (block) = decls;
 142
 143   /* The TREE_USED flag on a block determines whether the debug output
 144      routines generate info for the variables in that block.  */
 145   TREE_USED (block) = 1;
 146
 147   if (outer != NULL)
 148     {
 149       tree b = gimple_bind_block (outer);
 150       BLOCK_SUBBLOCKS (b) = chainon (BLOCK_SUBBLOCKS (b), block);
 151     }
 152   BLOCK_EXPR_BODY (java_block) = NULL_TREE;
 153
 154   return build3 (BIND_EXPR, TREE_TYPE (java_block), decls, body, block);
 155 }
 156
 157 /* Dump a tree of some kind.  This is a convenience wrapper for the
 158    dump_* functions in tree-dump.c.  */
 159 static void
 160 dump_java_tree (enum tree_dump_index phase, tree t)
 161 {
 162   FILE *stream;
 163   int flags;
 164
 165   stream = dump_begin (phase, &flags);
 166   flags |= TDF_SLIM;
 167   if (stream)
 168     {
 169       dump_node (t, flags, stream);
 170       dump_end (phase, stream);
 171     }
 172 }