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, 51 Franklin Street, Fifth Floor,
  19 Boston, MA 02110-1301, 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       gcc_unreachable ();
 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 = build1 (LABEL_EXPR, void_type_node, label);
 190   if (body != NULL_TREE)
 191     t = build2 (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 static tree
 212 java_gimplify_modify_expr (tree modify_expr)
 213 {
 214   tree lhs = TREE_OPERAND (modify_expr, 0);
 215   tree rhs = TREE_OPERAND (modify_expr, 1);
 216   tree lhs_type = TREE_TYPE (lhs);
 217
 218   /* This is specific to the bytecode compiler.  If a variable has
 219      LOCAL_SLOT_P set, replace an assignment to it with an assignment
 220      to the corresponding variable that holds all its aliases.  */
 221   if (TREE_CODE (lhs) == VAR_DECL
 222       && DECL_LANG_SPECIFIC (lhs)
 223       && LOCAL_SLOT_P (lhs)
 224       && TREE_CODE (lhs_type) == POINTER_TYPE)
 225     {
 226       tree new_lhs = java_replace_reference (lhs, /* want_lvalue */ true);
 227       tree new_rhs = build1 (NOP_EXPR, TREE_TYPE (new_lhs), rhs);
 228       modify_expr = build2 (MODIFY_EXPR, TREE_TYPE (new_lhs),
 229                             new_lhs, new_rhs);
 230       modify_expr = build1 (NOP_EXPR, lhs_type, modify_expr);
 231     }
 232   else if (lhs_type != TREE_TYPE (rhs))
 233     /* Fix up type mismatches to make legal GIMPLE.  These are
 234        generated in several places, in particular null pointer
 235        assignment and subclass assignment.  */
 236     TREE_OPERAND (modify_expr, 1) = convert (lhs_type, rhs);
 237
 238   return modify_expr;
 239 }
 240
 241
 242 static tree
 243 java_gimplify_case_expr (tree expr)
 244 {
 245   tree label = create_artificial_label ();
 246   return build3 (CASE_LABEL_EXPR, void_type_node,
 247                  TREE_OPERAND (expr, 0), NULL_TREE, label);
 248 }
 249
 250 static tree
 251 java_gimplify_default_expr (tree expr ATTRIBUTE_UNUSED)
 252 {
 253   tree label = create_artificial_label ();
 254   return build3 (CASE_LABEL_EXPR, void_type_node, NULL_TREE, NULL_TREE, label);
 255 }
 256
 257 /* Gimplify BLOCK into a BIND_EXPR.  */
 258
 259 static tree
 260 java_gimplify_block (tree java_block)
 261 {
 262   tree decls = BLOCK_VARS (java_block);
 263   tree body = BLOCK_EXPR_BODY (java_block);
 264   tree outer = gimple_current_bind_expr ();
 265   tree block;
 266
 267   /* Don't bother with empty blocks.  */
 268   if (! body)
 269     return build_empty_stmt ();
 270
 271   if (IS_EMPTY_STMT (body))
 272     return body;
 273
 274   /* Make a proper block.  Java blocks are unsuitable for BIND_EXPR
 275      because they use BLOCK_SUBBLOCKS for another purpose.  */
 276   block = make_node (BLOCK);
 277   BLOCK_VARS (block) = decls;
 278
 279   /* The TREE_USED flag on a block determines whether the debug output
 280      routines generate info for the variables in that block.  */
 281   TREE_USED (block) = 1;
 282
 283   if (outer != NULL_TREE)
 284     {
 285       outer = BIND_EXPR_BLOCK (outer);
 286       BLOCK_SUBBLOCKS (outer) = chainon (BLOCK_SUBBLOCKS (outer), block);
 287     }
 288   BLOCK_EXPR_BODY (java_block) = NULL_TREE;
 289
 290   return build3 (BIND_EXPR, TREE_TYPE (java_block), decls, body, block);
 291 }
 292
 293 /* Gimplify a NEW_ARRAY_INIT node into array/element assignments.  */
 294
 295 static tree
 296 java_gimplify_new_array_init (tree exp)
 297 {
 298   tree array_type = TREE_TYPE (TREE_TYPE (exp));
 299   tree data_field = lookup_field (&array_type, get_identifier ("data"));
 300   tree element_type = TYPE_ARRAY_ELEMENT (array_type);
 301   HOST_WIDE_INT ilength = java_array_type_length (array_type);
 302   tree length = build_int_cst (NULL_TREE, ilength);
 303   tree init = TREE_OPERAND (exp, 0);
 304   tree value;
 305   unsigned HOST_WIDE_INT cnt;
 306
 307   tree array_ptr_type = build_pointer_type (array_type);
 308   tree tmp = create_tmp_var (array_ptr_type, "array");
 309   tree body = build2 (MODIFY_EXPR, array_ptr_type, tmp,
 310                       build_new_array (element_type, length));
 311
 312   int index = 0;
 313
 314   /* FIXME: try to allocate array statically?  */
 315   FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (init), cnt, value)
 316     {
 317       /* FIXME: Should use build_java_arrayaccess here, but avoid
 318          bounds checking.  */
 319       tree lhs = build3 (COMPONENT_REF, TREE_TYPE (data_field),
 320                          build_java_indirect_ref (array_type, tmp, 0),
 321                          data_field, NULL_TREE);
 322       tree assignment = build2 (MODIFY_EXPR, element_type,
 323                                 build4 (ARRAY_REF, element_type, lhs,
 324                                         build_int_cst (NULL_TREE, index++),
 325                                         NULL_TREE, NULL_TREE),
 326                                 value);
 327       body = build2 (COMPOUND_EXPR, element_type, body, assignment);
 328     }
 329
 330   return build2 (COMPOUND_EXPR, array_ptr_type, body, tmp);
 331 }
 332
 333 static tree
 334 java_gimplify_try_expr (tree try_expr)
 335 {
 336   tree body = TREE_OPERAND (try_expr, 0);
 337   tree handler = TREE_OPERAND (try_expr, 1);
 338   tree catch = NULL_TREE;
 339
 340   /* Build a CATCH_EXPR for each handler.  */
 341   while (handler)
 342     {
 343       tree java_catch = TREE_OPERAND (handler, 0);
 344       tree catch_type = TREE_TYPE (TREE_TYPE (BLOCK_EXPR_DECLS (java_catch)));
 345       tree expr = build2 (CATCH_EXPR, void_type_node,
 346                           prepare_eh_table_type (catch_type),
 347                           handler);
 348       if (catch)
 349         catch = build2 (COMPOUND_EXPR, void_type_node, catch, expr);
 350       else
 351         catch = expr;
 352       handler = TREE_CHAIN (handler);
 353     }
 354   return build2 (TRY_CATCH_EXPR, void_type_node, body, catch);
 355 }
 356
 357 /* Dump a tree of some kind.  This is a convenience wrapper for the
 358    dump_* functions in tree-dump.c.  */
 359 static void
 360 dump_java_tree (enum tree_dump_index phase, tree t)
 361 {
 362   FILE *stream;
 363   int flags;
 364
 365   stream = dump_begin (phase, &flags);
 366   flags |= TDF_SLIM;
 367   if (stream)
 368     {
 369       dump_node (t, flags, stream);
 370       dump_end (phase, stream);
 371     }
 372 }