/* Java(TM) language-specific gimplification routines.
Copyright (C) 2003, 2004, 2006, 2007, 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 3, 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 COPYING3. If not see
.
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_block (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 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;
}
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);
}
/* 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);
}
}