/* Java(TM) language-specific gimplification routines. Copyright (C) 2003, 2004, 2006, 2007 Free Software Foundation, Inc. This file is part of GCC. GCC is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GCC is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GCC; see the file COPYING. If not, write to the Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. Java and all Java-based marks are trademarks or registered trademarks of Sun Microsystems, Inc. in the United States and other countries. The Free Software Foundation is independent of Sun Microsystems, Inc. */ #include "config.h" #include "system.h" #include "coretypes.h" #include "tm.h" #include "tree.h" #include "java-tree.h" #include "tree-dump.h" #include "tree-gimple.h" #include "toplev.h" static tree java_gimplify_labeled_block_expr (tree); static tree java_gimplify_exit_block_expr (tree); static tree java_gimplify_block (tree); static tree java_gimplify_try_expr (tree); static enum gimplify_status java_gimplify_modify_expr (tree*, tree*, tree *); static enum gimplify_status java_gimplify_component_ref (tree*, tree*, tree *); static enum gimplify_status java_gimplify_self_mod_expr (tree*, tree*, tree *); static void dump_java_tree (enum tree_dump_index, tree); /* Convert a Java tree to GENERIC. */ void java_genericize (tree fndecl) { dump_java_tree (TDI_original, fndecl); /* Genericize with the gimplifier. */ gimplify_function_tree (fndecl); dump_function (TDI_generic, fndecl); } /* Gimplify a Java tree. */ int java_gimplify_expr (tree *expr_p, tree *pre_p ATTRIBUTE_UNUSED, tree *post_p ATTRIBUTE_UNUSED) { enum tree_code code = TREE_CODE (*expr_p); switch (code) { case BLOCK: *expr_p = java_gimplify_block (*expr_p); break; case LABELED_BLOCK_EXPR: *expr_p = java_gimplify_labeled_block_expr (*expr_p); break; case EXIT_BLOCK_EXPR: *expr_p = java_gimplify_exit_block_expr (*expr_p); break; case TRY_EXPR: *expr_p = java_gimplify_try_expr (*expr_p); break; case VAR_DECL: *expr_p = java_replace_reference (*expr_p, /* want_lvalue */ false); return GS_UNHANDLED; /* We don't handle GIMPLE_MODIFY_STMT, as MODIFY_EXPRs with java semantics should only be generated by the front-end, and never by anything after gimplification. */ case MODIFY_EXPR: return java_gimplify_modify_expr (expr_p, pre_p, post_p); case SAVE_EXPR: /* Note that we can see if the save_expr was already handled by gimplify_save_expr. */ if (TREE_OPERAND (*expr_p, 0) != NULL_TREE && TREE_CODE (TREE_OPERAND (*expr_p, 0)) == VAR_DECL) TREE_OPERAND (*expr_p, 0) = java_replace_reference (TREE_OPERAND (*expr_p, 0), /* want_lvalue */ false); return GS_UNHANDLED; case POSTINCREMENT_EXPR: case POSTDECREMENT_EXPR: case PREINCREMENT_EXPR: case PREDECREMENT_EXPR: return java_gimplify_self_mod_expr (expr_p, pre_p, post_p); /* These should already be lowered before we get here. */ case URSHIFT_EXPR: case COMPARE_EXPR: case COMPARE_L_EXPR: case COMPARE_G_EXPR: gcc_unreachable (); case COMPONENT_REF: return java_gimplify_component_ref (expr_p, pre_p, post_p); default: /* Java insists on strict left-to-right evaluation of expressions. A problem may arise if a variable used in the LHS of a binary operation is altered by an assignment to that value in the RHS before we've performed the operation. So, we always copy every LHS to a temporary variable. FIXME: Are there any other cases where we should do this? Parameter lists, maybe? Or perhaps that's unnecessary because the front end already generates SAVE_EXPRs. */ if (TREE_CODE_CLASS (code) == tcc_binary || TREE_CODE_CLASS (code) == tcc_comparison) { enum gimplify_status stat = gimplify_expr (&TREE_OPERAND (*expr_p, 0), pre_p, post_p, is_gimple_formal_tmp_var, fb_rvalue); if (stat == GS_ERROR) return stat; } return GS_UNHANDLED; } return GS_OK; } /* Gimplify a LABELED_BLOCK_EXPR into a LABEL_EXPR following a (possibly empty) body. */ static tree java_gimplify_labeled_block_expr (tree expr) { tree body = LABELED_BLOCK_BODY (expr); tree label = LABELED_BLOCK_LABEL (expr); tree t; DECL_CONTEXT (label) = current_function_decl; t = build1 (LABEL_EXPR, void_type_node, label); if (body != NULL_TREE) t = build2 (COMPOUND_EXPR, void_type_node, body, t); return t; } /* Gimplify a EXIT_BLOCK_EXPR into a GOTO_EXPR. */ static tree java_gimplify_exit_block_expr (tree expr) { tree labeled_block = EXIT_BLOCK_LABELED_BLOCK (expr); tree label; /* First operand must be a LABELED_BLOCK_EXPR, which should already be lowered (or partially lowered) when we get here. */ gcc_assert (TREE_CODE (labeled_block) == LABELED_BLOCK_EXPR); label = LABELED_BLOCK_LABEL (labeled_block); return build1 (GOTO_EXPR, void_type_node, label); } static enum gimplify_status java_gimplify_component_ref (tree *expr_p, tree *pre_p, tree *post_p) { if (CLASS_FROM_SOURCE_P (output_class) && TREE_THIS_VOLATILE (TREE_OPERAND (*expr_p, 1)) && ! TREE_THIS_VOLATILE (*expr_p)) { enum gimplify_status stat; tree sync_expr; /* Special handling for volatile fields. A load has "acquire" semantics, implying that you can't move up later operations. A store has "release" semantics meaning that earlier operations cannot be delayed past it. This logic only handles loads: stores are handled in java_gimplify_modify_expr(). We gimplify this COMPONENT_REF, put the result in a tmp_var, and then return a COMPOUND_EXPR of the form {__sync_synchronize(); tmp_var}. This forces __sync_synchronize() to be placed immediately after loading from the volatile field. */ TREE_THIS_VOLATILE (*expr_p) = 1; *expr_p = java_modify_addr_for_volatile (*expr_p); stat = gimplify_expr (expr_p, pre_p, post_p, is_gimple_formal_tmp_var, fb_rvalue); if (stat == GS_ERROR) return stat; sync_expr = build_call_expr (built_in_decls[BUILT_IN_SYNCHRONIZE], 0); TREE_SIDE_EFFECTS (sync_expr) = 1; *expr_p = build2 (COMPOUND_EXPR, TREE_TYPE (*expr_p), sync_expr, *expr_p); TREE_SIDE_EFFECTS (*expr_p) = 1; } return GS_UNHANDLED; } static enum gimplify_status java_gimplify_modify_expr (tree *modify_expr_p, tree *pre_p, tree *post_p) { tree modify_expr = *modify_expr_p; tree lhs = TREE_OPERAND (modify_expr, 0); tree rhs = TREE_OPERAND (modify_expr, 1); tree lhs_type = TREE_TYPE (lhs); if (CLASS_FROM_SOURCE_P (output_class) && TREE_CODE (lhs) == COMPONENT_REF && TREE_THIS_VOLATILE (TREE_OPERAND (lhs, 1))) { /* Special handling for volatile fields. A load has "acquire" semantics, implying that you can't move up later operations. A store has "release" semantics meaning that earlier operations cannot be delayed past it. This logic only handles stores; loads are handled in java_gimplify_component_ref(). We gimplify the rhs, put the result in a tmp_var, and then return a MODIFY_EXPR with an rhs of the form {__sync_synchronize(); tmp_var}. This forces __sync_synchronize() to be placed after evaluating the rhs and immediately before storing to the volatile field. */ enum gimplify_status stat; tree sync_expr = build_call_expr (built_in_decls[BUILT_IN_SYNCHRONIZE], 0); TREE_SIDE_EFFECTS (sync_expr) = 1; stat = gimplify_expr (&rhs, pre_p, post_p, is_gimple_formal_tmp_var, fb_rvalue); if (stat == GS_ERROR) return stat; rhs = build2 (COMPOUND_EXPR, TREE_TYPE (rhs), sync_expr, rhs); TREE_SIDE_EFFECTS (rhs) = 1; TREE_THIS_VOLATILE (lhs) = 1; lhs = java_modify_addr_for_volatile (lhs); TREE_OPERAND (modify_expr, 0) = lhs; TREE_OPERAND (modify_expr, 1) = rhs; } /* This is specific to the bytecode compiler. If a variable has LOCAL_SLOT_P set, replace an assignment to it with an assignment to the corresponding variable that holds all its aliases. */ if (TREE_CODE (lhs) == VAR_DECL && DECL_LANG_SPECIFIC (lhs) && LOCAL_SLOT_P (lhs) && TREE_CODE (lhs_type) == POINTER_TYPE) { tree new_lhs = java_replace_reference (lhs, /* want_lvalue */ true); tree new_rhs = build1 (NOP_EXPR, TREE_TYPE (new_lhs), rhs); modify_expr = build2 (GIMPLE_MODIFY_STMT, TREE_TYPE (new_lhs), new_lhs, new_rhs); modify_expr = build1 (NOP_EXPR, lhs_type, modify_expr); } else if (lhs_type != TREE_TYPE (rhs)) /* Fix up type mismatches to make legal GIMPLE. These are generated in several places, in particular null pointer assignment and subclass assignment. */ TREE_OPERAND (modify_expr, 1) = convert (lhs_type, rhs); *modify_expr_p = modify_expr; return GS_UNHANDLED; } /* Special case handling for volatiles: we need to generate a barrier between the reading and the writing. */ static enum gimplify_status java_gimplify_self_mod_expr (tree *expr_p, tree *pre_p ATTRIBUTE_UNUSED, tree *post_p ATTRIBUTE_UNUSED) { tree lhs = TREE_OPERAND (*expr_p, 0); if (TREE_CODE (lhs) == COMPONENT_REF && TREE_THIS_VOLATILE (TREE_OPERAND (lhs, 1))) TREE_THIS_VOLATILE (lhs) = 1; return GS_UNHANDLED; } /* Gimplify BLOCK into a BIND_EXPR. */ static tree java_gimplify_block (tree java_block) { tree decls = BLOCK_VARS (java_block); tree body = BLOCK_EXPR_BODY (java_block); tree outer = gimple_current_bind_expr (); tree block; /* Don't bother with empty blocks. */ if (! body) return build_empty_stmt (); if (IS_EMPTY_STMT (body)) return body; /* Make a proper block. Java blocks are unsuitable for BIND_EXPR because they use BLOCK_SUBBLOCKS for another purpose. */ block = make_node (BLOCK); BLOCK_VARS (block) = decls; /* The TREE_USED flag on a block determines whether the debug output routines generate info for the variables in that block. */ TREE_USED (block) = 1; if (outer != NULL_TREE) { outer = BIND_EXPR_BLOCK (outer); BLOCK_SUBBLOCKS (outer) = chainon (BLOCK_SUBBLOCKS (outer), block); } BLOCK_EXPR_BODY (java_block) = NULL_TREE; return build3 (BIND_EXPR, TREE_TYPE (java_block), decls, body, block); } static tree java_gimplify_try_expr (tree try_expr) { tree body = TREE_OPERAND (try_expr, 0); tree handler = TREE_OPERAND (try_expr, 1); tree catch = NULL_TREE; /* Build a CATCH_EXPR for each handler. */ while (handler) { tree java_catch = TREE_OPERAND (handler, 0); tree catch_type = TREE_TYPE (TREE_TYPE (BLOCK_EXPR_DECLS (java_catch))); tree expr = build2 (CATCH_EXPR, void_type_node, prepare_eh_table_type (catch_type), handler); if (catch) catch = build2 (COMPOUND_EXPR, void_type_node, catch, expr); else catch = expr; handler = TREE_CHAIN (handler); } return build2 (TRY_CATCH_EXPR, void_type_node, body, catch); } /* Dump a tree of some kind. This is a convenience wrapper for the dump_* functions in tree-dump.c. */ static void dump_java_tree (enum tree_dump_index phase, tree t) { FILE *stream; int flags; stream = dump_begin (phase, &flags); flags |= TDF_SLIM; if (stream) { dump_node (t, flags, stream); dump_end (phase, stream); } }