gcc/java/java-gimplify.c

   1 /* Java(TM) language-specific gimplification routines.
   2    Copyright (C) 2003, 2004 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 2, 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 COPYING.  If not, write to
  18 the Free Software Foundation, 59 Temple Place - Suite 330,
  19 Boston, MA 02111-1307, USA.
  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 "tree-gimple.h"
  33 #include "toplev.h"
  34
  35 static tree java_gimplify_case_expr (tree);
  36 static tree java_gimplify_default_expr (tree);
  37 static tree java_gimplify_block (tree);
  38 static tree java_gimplify_new_array_init (tree);
  39 static tree java_gimplify_try_expr (tree);
  40 static tree java_gimplify_modify_expr (tree);
  41
  42 static void dump_java_tree (enum tree_dump_index, tree);
  43
  44 /* Convert a Java tree to GENERIC.  */
  45
  46 void
  47 java_genericize (tree fndecl)
  48 {
  49   dump_java_tree (TDI_original, fndecl);
  50
  51   /* Genericize with the gimplifier.  */
  52   gimplify_function_tree (fndecl);
  53
  54   dump_function (TDI_generic, fndecl);
  55 }
  56
  57 /* Gimplify a Java tree.  */
  58
  59 int
  60 java_gimplify_expr (tree *expr_p, tree *pre_p ATTRIBUTE_UNUSED,
  61                     tree *post_p ATTRIBUTE_UNUSED)
  62 {
  63   enum tree_code code = TREE_CODE (*expr_p);
  64
  65   switch (code)
  66     {
  67     case BLOCK:
  68       *expr_p = java_gimplify_block (*expr_p);
  69       break;
  70
  71     case EXPR_WITH_FILE_LOCATION:
  72       input_location.file = EXPR_WFL_FILENAME (*expr_p);
  73       input_location.line = EXPR_WFL_LINENO (*expr_p);
  74       *expr_p = EXPR_WFL_NODE (*expr_p);
  75       annotate_with_locus (*expr_p, input_location);
  76       break;
  77
  78     case CASE_EXPR:
  79       *expr_p = java_gimplify_case_expr (*expr_p);
  80       break;
  81
  82     case DEFAULT_EXPR:
  83       *expr_p = java_gimplify_default_expr (*expr_p);
  84       break;
  85
  86     case NEW_ARRAY_INIT:
  87       *expr_p = java_gimplify_new_array_init (*expr_p);
  88       break;
  89
  90     case TRY_EXPR:
  91       *expr_p = java_gimplify_try_expr (*expr_p);
  92       break;
  93
  94     case JAVA_CATCH_EXPR:
  95       *expr_p = TREE_OPERAND (*expr_p, 0);
  96       break;
  97
  98     case JAVA_EXC_OBJ_EXPR:
  99       *expr_p = build_exception_object_ref (TREE_TYPE (*expr_p));
 100       break;
 101
 102     case VAR_DECL:
 103       *expr_p = java_replace_reference (*expr_p, /* want_lvalue */ false);
 104       return GS_UNHANDLED;
 105
 106     case MODIFY_EXPR:
 107       *expr_p = java_gimplify_modify_expr (*expr_p);
 108       return GS_UNHANDLED;
 109
 110     case SAVE_EXPR:
 111       if (TREE_CODE (TREE_OPERAND (*expr_p, 0)) == VAR_DECL)
 112         TREE_OPERAND (*expr_p, 0)
 113           = java_replace_reference (TREE_OPERAND (*expr_p, 0),
 114                                /* want_lvalue */ false);
 115       return GS_UNHANDLED;
 116
 117     /* These should already be lowered before we get here.  */
 118     case URSHIFT_EXPR:
 119     case COMPARE_EXPR:
 120     case COMPARE_L_EXPR:
 121     case COMPARE_G_EXPR:
 122     case UNARY_PLUS_EXPR:
 123     case NEW_ARRAY_EXPR:
 124     case NEW_ANONYMOUS_ARRAY_EXPR:
 125     case NEW_CLASS_EXPR:
 126     case THIS_EXPR:
 127     case SYNCHRONIZED_EXPR:
 128     case CONDITIONAL_EXPR:
 129     case INSTANCEOF_EXPR:
 130     case CLASS_LITERAL:
 131       abort ();
 132
 133     default:
 134       /* Java insists on strict left-to-right evaluation of expressions.
 135          A problem may arise if a variable used in the LHS of a binary
 136          operation is altered by an assignment to that value in the RHS
 137          before we've performed the operation.  So, we always copy every
 138          LHS to a temporary variable.
 139
 140          FIXME: Are there any other cases where we should do this?
 141          Parameter lists, maybe?  Or perhaps that's unnecessary because
 142          the front end already generates SAVE_EXPRs.  */
 143
 144       if (TREE_CODE_CLASS (code) == tcc_binary
 145           || TREE_CODE_CLASS (code) == tcc_comparison)
 146         {
 147           enum gimplify_status stat
 148             = gimplify_expr (&TREE_OPERAND (*expr_p, 0), pre_p, post_p,
 149                              is_gimple_formal_tmp_var, fb_rvalue);
 150           if (stat == GS_ERROR)
 151             return stat;
 152         }
 153
 154       return GS_UNHANDLED;
 155     }
 156
 157   return GS_OK;
 158 }
 159
 160 /* This is specific to the bytecode compiler.  If a variable has
 161    LOCAL_SLOT_P set, replace an assignment to it with an assignment to
 162    the corresponding variable that holds all its aliases.  */
 163
 164 static tree
 165 java_gimplify_modify_expr (tree modify_expr)
 166 {
 167   tree lhs = TREE_OPERAND (modify_expr, 0);
 168   tree rhs = TREE_OPERAND (modify_expr, 1);
 169   tree lhs_type = TREE_TYPE (lhs);
 170
 171   if (TREE_CODE (lhs) == VAR_DECL
 172       && DECL_LANG_SPECIFIC (lhs)
 173       && LOCAL_SLOT_P (lhs)
 174       && TREE_CODE (lhs_type) == POINTER_TYPE)
 175     {
 176       tree new_lhs = java_replace_reference (lhs, /* want_lvalue */ true);
 177       tree new_rhs = build1 (NOP_EXPR, TREE_TYPE (new_lhs), rhs);
 178       modify_expr = build2 (MODIFY_EXPR, TREE_TYPE (new_lhs),
 179                             new_lhs, new_rhs);
 180       modify_expr = build1 (NOP_EXPR, lhs_type, modify_expr);
 181     }
 182
 183   return modify_expr;
 184 }
 185
 186
 187 static tree
 188 java_gimplify_case_expr (tree expr)
 189 {
 190   tree label = create_artificial_label ();
 191   return build3 (CASE_LABEL_EXPR, void_type_node,
 192                  TREE_OPERAND (expr, 0), NULL_TREE, label);
 193 }
 194
 195 static tree
 196 java_gimplify_default_expr (tree expr ATTRIBUTE_UNUSED)
 197 {
 198   tree label = create_artificial_label ();
 199   return build3 (CASE_LABEL_EXPR, void_type_node, NULL_TREE, NULL_TREE, label);
 200 }
 201
 202 /* Gimplify BLOCK into a BIND_EXPR.  */
 203
 204 static tree
 205 java_gimplify_block (tree java_block)
 206 {
 207   tree decls = BLOCK_VARS (java_block);
 208   tree body = BLOCK_EXPR_BODY (java_block);
 209   tree outer = gimple_current_bind_expr ();
 210   tree block;
 211
 212   /* Don't bother with empty blocks.  */
 213   if (! body)
 214     return build_empty_stmt ();
 215
 216   if (IS_EMPTY_STMT (body))
 217     return body;
 218
 219   /* Make a proper block.  Java blocks are unsuitable for BIND_EXPR
 220      because they use BLOCK_SUBBLOCKS for another purpose.  */
 221   block = make_node (BLOCK);
 222   BLOCK_VARS (block) = decls;
 223
 224   /* The TREE_USED flag on a block determines whether the debug ouput
 225      routines generate info for the variables in that block.  */
 226   TREE_USED (block) = 1;
 227
 228   if (outer != NULL_TREE)
 229     {
 230       outer = BIND_EXPR_BLOCK (outer);
 231       BLOCK_SUBBLOCKS (outer) = chainon (BLOCK_SUBBLOCKS (outer), block);
 232     }
 233
 234   return build3 (BIND_EXPR, TREE_TYPE (java_block), decls, body, block);
 235 }
 236
 237 /* Gimplify a NEW_ARRAY_INIT node into array/element assignments.  */
 238
 239 static tree
 240 java_gimplify_new_array_init (tree exp)
 241 {
 242   tree array_type = TREE_TYPE (TREE_TYPE (exp));
 243   tree data_field = lookup_field (&array_type, get_identifier ("data"));
 244   tree element_type = TYPE_ARRAY_ELEMENT (array_type);
 245   HOST_WIDE_INT ilength = java_array_type_length (array_type);
 246   tree length = build_int_cst (NULL_TREE, ilength);
 247   tree init = TREE_OPERAND (exp, 0);
 248   tree values = CONSTRUCTOR_ELTS (init);
 249
 250   tree array_ptr_type = build_pointer_type (array_type);
 251   tree tmp = create_tmp_var (array_ptr_type, "array");
 252   tree body = build2 (MODIFY_EXPR, array_ptr_type, tmp,
 253                       build_new_array (element_type, length));
 254
 255   int index = 0;
 256
 257   /* FIXME: try to allocate array statically?  */
 258   while (values != NULL_TREE)
 259     {
 260       /* FIXME: Should use build_java_arrayaccess here, but avoid
 261          bounds checking.  */
 262       tree lhs = build3 (COMPONENT_REF, TREE_TYPE (data_field),
 263                          build_java_indirect_ref (array_type, tmp, 0),
 264                          data_field, NULL_TREE);
 265       tree assignment = build2 (MODIFY_EXPR, element_type,
 266                                 build4 (ARRAY_REF, element_type, lhs,
 267                                         build_int_cst (NULL_TREE, index++),
 268                                         NULL_TREE, NULL_TREE),
 269                                 TREE_VALUE (values));
 270       body = build2 (COMPOUND_EXPR, element_type, body, assignment);
 271       values = TREE_CHAIN (values);
 272     }
 273
 274   return build2 (COMPOUND_EXPR, array_ptr_type, body, tmp);
 275 }
 276
 277 static tree
 278 java_gimplify_try_expr (tree try_expr)
 279 {
 280   tree body = TREE_OPERAND (try_expr, 0);
 281   tree handler = TREE_OPERAND (try_expr, 1);
 282   tree catch = NULL_TREE;
 283
 284   /* Build a CATCH_EXPR for each handler.  */
 285   while (handler)
 286     {
 287       tree java_catch = TREE_OPERAND (handler, 0);
 288       tree catch_type = TREE_TYPE (TREE_TYPE (BLOCK_EXPR_DECLS (java_catch)));
 289       tree expr = build2 (CATCH_EXPR, void_type_node,
 290                           prepare_eh_table_type (catch_type),
 291                           handler);
 292       if (catch)
 293         catch = build2 (COMPOUND_EXPR, void_type_node, catch, expr);
 294       else
 295         catch = expr;
 296       handler = TREE_CHAIN (handler);
 297     }
 298   return build2 (TRY_CATCH_EXPR, void_type_node, body, catch);
 299 }
 300
 301 /* Dump a tree of some kind.  This is a convenience wrapper for the
 302    dump_* functions in tree-dump.c.  */
 303 static void
 304 dump_java_tree (enum tree_dump_index phase, tree t)
 305 {
 306   FILE *stream;
 307   int flags;
 308
 309   stream = dump_begin (phase, &flags);
 310   flags |= TDF_SLIM;
 311   if (stream)
 312     {
 313       dump_node (t, flags, stream);
 314       dump_end (phase, stream);
 315     }
 316 }