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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
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* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
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*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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package sun.tools.tree;
import sun.tools.java.*;
import sun.tools.asm.Assembler;
import java.io.PrintStream;
import java.util.Hashtable;
/**
* WARNING: The contents of this source file are not part of any
* supported API. Code that depends on them does so at its own risk:
* they are subject to change or removal without notice.
*/
public
class AssignExpression extends BinaryAssignExpression {
private FieldUpdater updater = null;
/**
* Constructor
*/
public AssignExpression(long where, Expression left, Expression right) {
super(ASSIGN, where, left, right);
}
/**
* Check an assignment expression
*/
public Vset checkValue(Environment env, Context ctx, Vset vset, Hashtable exp) {
if (left instanceof IdentifierExpression) {
// we don't want to mark an identifier as having a value
// until having evaluated the right-hand side
vset = right.checkValue(env, ctx, vset, exp);
vset = left.checkLHS(env, ctx, vset, exp);
} else {
// normally left to right evaluation.
vset = left.checkLHS(env, ctx, vset, exp);
vset = right.checkValue(env, ctx, vset, exp);
}
type = left.type;
right = convert(env, ctx, type, right);
// Get field updater (access method) if needed, else null.
updater = left.getAssigner(env, ctx);
return vset;
}
/**
* Inline
*/
public Expression inlineValue(Environment env, Context ctx) {
if (implementation != null)
return implementation.inlineValue(env, ctx);
// Must be 'inlineLHS' here. But compare with similar case in
// 'AssignOpExpression' and 'IncDecExpression', which needs 'inlineValue'.
left = left.inlineLHS(env, ctx);
right = right.inlineValue(env, ctx);
if (updater != null) {
updater = updater.inline(env, ctx);
}
return this;
}
/**
* Create a copy of the expression for method inlining
*/
public Expression copyInline(Context ctx) {
if (implementation != null)
return implementation.copyInline(ctx);
AssignExpression e = (AssignExpression)clone();
e.left = left.copyInline(ctx);
e.right = right.copyInline(ctx);
if (updater != null) {
e.updater = updater.copyInline(ctx);
}
return e;
}
/**
* The cost of inlining this expression
*/
public int costInline(int thresh, Environment env, Context ctx) {
/*----------*
return 2 + super.costInline(thresh, env, ctx);
*----------*/
return (updater != null)
// Cost of rhs expression + cost of access method call.
// Access method call cost includes lhs cost.
? right.costInline(thresh, env, ctx) +
updater.costInline(thresh, env, ctx, false)
// Cost of rhs expression + cost of lhs expression +
// cost of store instruction.
: right.costInline(thresh, env, ctx) +
left.costInline(thresh, env, ctx) + 2;
}
/**
* Code
*/
public void codeValue(Environment env, Context ctx, Assembler asm) {
if (updater == null) {
// Field is directly accessible.
int depth = left.codeLValue(env, ctx, asm);
right.codeValue(env, ctx, asm);
codeDup(env, ctx, asm, right.type.stackSize(), depth);
left.codeStore(env, ctx, asm);
} else {
// Must use access method.
// Left operand is always a 'FieldExpression', or
// is rewritten as one via 'implementation'.
updater.startAssign(env, ctx, asm);
right.codeValue(env, ctx, asm);
updater.finishAssign(env, ctx, asm, true);
}
}
public void code(Environment env, Context ctx, Assembler asm) {
if (updater == null) {
// Field is directly accessible.
left.codeLValue(env, ctx, asm);
right.codeValue(env, ctx, asm);
left.codeStore(env, ctx, asm);
} else {
// Must use access method.
// Left operand is always a 'FieldExpression', or
// is rewritten as one via 'implementation'.
updater.startAssign(env, ctx, asm);
right.codeValue(env, ctx, asm);
updater.finishAssign(env, ctx, asm, false);
}
}
}