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_labeled_block_expr (tree);
  36 static tree java_gimplify_exit_block_expr (tree);
  37 static tree java_gimplify_case_expr (tree);
  38 static tree java_gimplify_default_expr (tree);
  39 static tree java_gimplify_block (tree);
  40 static tree java_gimplify_new_array_init (tree);
  41 static tree java_gimplify_try_expr (tree);
  42 static tree java_gimplify_modify_expr (tree);
  43
  44 static void dump_java_tree (enum tree_dump_index, tree);
  45
  46 /* Convert a Java tree to GENERIC.  */
  47
  48 void
  49 java_genericize (tree fndecl)
  50 {
  51   dump_java_tree (TDI_original, fndecl);
  52
  53   /* Genericize with the gimplifier.  */
  54   gimplify_function_tree (fndecl);
  55
  56   dump_function (TDI_generic, fndecl);
  57 }
  58
  59 /* Gimplify a Java tree.  */
  60
  61 int
  62 java_gimplify_expr (tree *expr_p, tree *pre_p ATTRIBUTE_UNUSED,
  63                     tree *post_p ATTRIBUTE_UNUSED)
  64 {
  65   enum tree_code code = TREE_CODE (*expr_p);
  66
  67   switch (code)
  68     {
  69     case BLOCK:
  70       *expr_p = java_gimplify_block (*expr_p);
  71       break;
  72
  73     case EXPR_WITH_FILE_LOCATION:
  74 #ifdef USE_MAPPED_LOCATION
  75       input_location = EXPR_LOCATION (*expr_p);
  76 #else
  77       input_location.file = EXPR_WFL_FILENAME (*expr_p);
  78       input_location.line = EXPR_WFL_LINENO (*expr_p);
  79 #endif
  80       *expr_p = EXPR_WFL_NODE (*expr_p);
  81       if (EXPR_P (*expr_p))
  82         SET_EXPR_LOCATION (*expr_p, input_location);
  83       break;
  84
  85     case LABELED_BLOCK_EXPR:
  86       *expr_p = java_gimplify_labeled_block_expr (*expr_p);
  87       break;
  88
  89     case EXIT_BLOCK_EXPR:
  90       *expr_p = java_gimplify_exit_block_expr (*expr_p);
  91       break;
  92
  93     case CASE_EXPR:
  94       *expr_p = java_gimplify_case_expr (*expr_p);
  95       break;
  96
  97     case DEFAULT_EXPR:
  98       *expr_p = java_gimplify_default_expr (*expr_p);
  99       break;
 100
 101     case NEW_ARRAY_INIT:
 102       *expr_p = java_gimplify_new_array_init (*expr_p);
 103       break;
 104
 105     case TRY_EXPR:
 106       *expr_p = java_gimplify_try_expr (*expr_p);
 107       break;
 108
 109     case JAVA_CATCH_EXPR:
 110       *expr_p = TREE_OPERAND (*expr_p, 0);
 111       break;
 112
 113     case JAVA_EXC_OBJ_EXPR:
 114       *expr_p = build_exception_object_ref (TREE_TYPE (*expr_p));
 115       break;
 116
 117     case VAR_DECL:
 118       *expr_p = java_replace_reference (*expr_p, /* want_lvalue */ false);
 119       return GS_UNHANDLED;
 120
 121     case MODIFY_EXPR:
 122       *expr_p = java_gimplify_modify_expr (*expr_p);
 123       return GS_UNHANDLED;
 124
 125     case SAVE_EXPR:
 126       /* Note that we can see <save_expr NULL> if the save_expr was
 127          already handled by gimplify_save_expr.  */
 128       if (TREE_OPERAND (*expr_p, 0) != NULL_TREE
 129           && TREE_CODE (TREE_OPERAND (*expr_p, 0)) == VAR_DECL)
 130         TREE_OPERAND (*expr_p, 0)
 131           = java_replace_reference (TREE_OPERAND (*expr_p, 0),
 132                                /* want_lvalue */ false);
 133       return GS_UNHANDLED;
 134
 135     /* These should already be lowered before we get here.  */
 136     case URSHIFT_EXPR:
 137     case COMPARE_EXPR:
 138     case COMPARE_L_EXPR:
 139     case COMPARE_G_EXPR:
 140     case UNARY_PLUS_EXPR:
 141     case NEW_ARRAY_EXPR:
 142     case NEW_ANONYMOUS_ARRAY_EXPR:
 143     case NEW_CLASS_EXPR:
 144     case THIS_EXPR:
 145     case SYNCHRONIZED_EXPR:
 146     case CONDITIONAL_EXPR:
 147     case INSTANCEOF_EXPR:
 148     case CLASS_LITERAL:
 149       abort ();
 150
 151     default:
 152       /* Java insists on strict left-to-right evaluation of expressions.
 153          A problem may arise if a variable used in the LHS of a binary
 154          operation is altered by an assignment to that value in the RHS
 155          before we've performed the operation.  So, we always copy every
 156          LHS to a temporary variable.
 157
 158          FIXME: Are there any other cases where we should do this?
 159          Parameter lists, maybe?  Or perhaps that's unnecessary because
 160          the front end already generates SAVE_EXPRs.  */
 161
 162       if (TREE_CODE_CLASS (code) == tcc_binary
 163           || TREE_CODE_CLASS (code) == tcc_comparison)
 164         {
 165           enum gimplify_status stat
 166             = gimplify_expr (&TREE_OPERAND (*expr_p, 0), pre_p, post_p,
 167                              is_gimple_formal_tmp_var, fb_rvalue);
 168           if (stat == GS_ERROR)
 169             return stat;
 170         }
 171
 172       return GS_UNHANDLED;
 173     }
 174
 175   return GS_OK;
 176 }
 177
 178 /* Gimplify a LABELED_BLOCK_EXPR into a LABEL_EXPR following
 179    a (possibly empty) body.  */
 180
 181 static tree
 182 java_gimplify_labeled_block_expr (tree expr)
 183 {
 184   tree body = LABELED_BLOCK_BODY (expr);
 185   tree label = LABELED_BLOCK_LABEL (expr);
 186   tree t;
 187
 188   DECL_CONTEXT (label) = current_function_decl;
 189   t = build (LABEL_EXPR, void_type_node, label);
 190   if (body != NULL_TREE)
 191     t = build (COMPOUND_EXPR, void_type_node, body, t);
 192   return t;
 193 }
 194
 195 /* Gimplify a EXIT_BLOCK_EXPR into a GOTO_EXPR.  */
 196
 197 static tree
 198 java_gimplify_exit_block_expr (tree expr)
 199 {
 200   tree labeled_block = EXIT_BLOCK_LABELED_BLOCK (expr);
 201   tree label;
 202
 203   /* First operand must be a LABELED_BLOCK_EXPR, which should
 204      already be lowered (or partially lowered) when we get here.  */
 205   gcc_assert (TREE_CODE (labeled_block) == LABELED_BLOCK_EXPR);
 206
 207   label = LABELED_BLOCK_LABEL (labeled_block);
 208   return build1 (GOTO_EXPR, void_type_node, label);
 209 }
 210
 211 /* This is specific to the bytecode compiler.  If a variable has
 212    LOCAL_SLOT_P set, replace an assignment to it with an assignment to
 213    the corresponding variable that holds all its aliases.  */
 214
 215 static tree
 216 java_gimplify_modify_expr (tree modify_expr)
 217 {
 218   tree lhs = TREE_OPERAND (modify_expr, 0);
 219   tree rhs = TREE_OPERAND (modify_expr, 1);
 220   tree lhs_type = TREE_TYPE (lhs);
 221
 222   if (TREE_CODE (lhs) == VAR_DECL
 223       && DECL_LANG_SPECIFIC (lhs)
 224       && LOCAL_SLOT_P (lhs)
 225       && TREE_CODE (lhs_type) == POINTER_TYPE)
 226     {
 227       tree new_lhs = java_replace_reference (lhs, /* want_lvalue */ true);
 228       tree new_rhs = build1 (NOP_EXPR, TREE_TYPE (new_lhs), rhs);
 229       modify_expr = build2 (MODIFY_EXPR, TREE_TYPE (new_lhs),
 230                             new_lhs, new_rhs);
 231       modify_expr = build1 (NOP_EXPR, lhs_type, modify_expr);
 232     }
 233
 234   return modify_expr;
 235 }
 236
 237
 238 static tree
 239 java_gimplify_case_expr (tree expr)
 240 {
 241   tree label = create_artificial_label ();
 242   return build3 (CASE_LABEL_EXPR, void_type_node,
 243                  TREE_OPERAND (expr, 0), NULL_TREE, label);
 244 }
 245
 246 static tree
 247 java_gimplify_default_expr (tree expr ATTRIBUTE_UNUSED)
 248 {
 249   tree label = create_artificial_label ();
 250   return build3 (CASE_LABEL_EXPR, void_type_node, NULL_TREE, NULL_TREE, label);
 251 }
 252
 253 /* Gimplify BLOCK into a BIND_EXPR.  */
 254
 255 static tree
 256 java_gimplify_block (tree java_block)
 257 {
 258   tree decls = BLOCK_VARS (java_block);
 259   tree body = BLOCK_EXPR_BODY (java_block);
 260   tree outer = gimple_current_bind_expr ();
 261   tree block;
 262
 263   /* Don't bother with empty blocks.  */
 264   if (! body)
 265     return build_empty_stmt ();
 266
 267   if (IS_EMPTY_STMT (body))
 268     return body;
 269
 270   /* Make a proper block.  Java blocks are unsuitable for BIND_EXPR
 271      because they use BLOCK_SUBBLOCKS for another purpose.  */
 272   block = make_node (BLOCK);
 273   BLOCK_VARS (block) = decls;
 274
 275   /* The TREE_USED flag on a block determines whether the debug ouput
 276      routines generate info for the variables in that block.  */
 277   TREE_USED (block) = 1;
 278
 279   if (outer != NULL_TREE)
 280     {
 281       outer = BIND_EXPR_BLOCK (outer);
 282       BLOCK_SUBBLOCKS (outer) = chainon (BLOCK_SUBBLOCKS (outer), block);
 283     }
 284
 285   return build3 (BIND_EXPR, TREE_TYPE (java_block), decls, body, block);
 286 }
 287
 288 /* Gimplify a NEW_ARRAY_INIT node into array/element assignments.  */
 289
 290 static tree
 291 java_gimplify_new_array_init (tree exp)
 292 {
 293   tree array_type = TREE_TYPE (TREE_TYPE (exp));
 294   tree data_field = lookup_field (&array_type, get_identifier ("data"));
 295   tree element_type = TYPE_ARRAY_ELEMENT (array_type);
 296   HOST_WIDE_INT ilength = java_array_type_length (array_type);
 297   tree length = build_int_cst (NULL_TREE, ilength);
 298   tree init = TREE_OPERAND (exp, 0);
 299   tree values = CONSTRUCTOR_ELTS (init);
 300
 301   tree array_ptr_type = build_pointer_type (array_type);
 302   tree tmp = create_tmp_var (array_ptr_type, "array");
 303   tree body = build2 (MODIFY_EXPR, array_ptr_type, tmp,
 304                       build_new_array (element_type, length));
 305
 306   int index = 0;
 307
 308   /* FIXME: try to allocate array statically?  */
 309   while (values != NULL_TREE)
 310     {
 311       /* FIXME: Should use build_java_arrayaccess here, but avoid
 312          bounds checking.  */
 313       tree lhs = build3 (COMPONENT_REF, TREE_TYPE (data_field),
 314                          build_java_indirect_ref (array_type, tmp, 0),
 315                          data_field, NULL_TREE);
 316       tree assignment = build2 (MODIFY_EXPR, element_type,
 317                                 build4 (ARRAY_REF, element_type, lhs,
 318                                         build_int_cst (NULL_TREE, index++),
 319                                         NULL_TREE, NULL_TREE),
 320                                 TREE_VALUE (values));
 321       body = build2 (COMPOUND_EXPR, element_type, body, assignment);
 322       values = TREE_CHAIN (values);
 323     }
 324
 325   return build2 (COMPOUND_EXPR, array_ptr_type, body, tmp);
 326 }
 327
 328 static tree
 329 java_gimplify_try_expr (tree try_expr)
 330 {
 331   tree body = TREE_OPERAND (try_expr, 0);
 332   tree handler = TREE_OPERAND (try_expr, 1);
 333   tree catch = NULL_TREE;
 334
 335   /* Build a CATCH_EXPR for each handler.  */
 336   while (handler)
 337     {
 338       tree java_catch = TREE_OPERAND (handler, 0);
 339       tree catch_type = TREE_TYPE (TREE_TYPE (BLOCK_EXPR_DECLS (java_catch)));
 340       tree expr = build2 (CATCH_EXPR, void_type_node,
 341                           prepare_eh_table_type (catch_type),
 342                           handler);
 343       if (catch)
 344         catch = build2 (COMPOUND_EXPR, void_type_node, catch, expr);
 345       else
 346         catch = expr;
 347       handler = TREE_CHAIN (handler);
 348     }
 349   return build2 (TRY_CATCH_EXPR, void_type_node, body, catch);
 350 }
 351
 352 /* Dump a tree of some kind.  This is a convenience wrapper for the
 353    dump_* functions in tree-dump.c.  */
 354 static void
 355 dump_java_tree (enum tree_dump_index phase, tree t)
 356 {
 357   FILE *stream;
 358   int flags;
 359
 360   stream = dump_begin (phase, &flags);
 361   flags |= TDF_SLIM;
 362   if (stream)
 363     {
 364       dump_node (t, flags, stream);
 365       dump_end (phase, stream);
 366     }
 367 }