/** Code generation for a binary operation */
public void generateCode(BlockScope currentScope, CodeStream codeStream, boolean valueRequired) {
int pc = codeStream.position;
if (this.constant != Constant.NotAConstant) {
// inlined value
if (valueRequired) codeStream.generateConstant(this.constant, this.implicitConversion);
codeStream.recordPositionsFrom(pc, this.sourceStart);
return;
}
Constant cst = this.right.constant;
if (cst != Constant.NotAConstant) {
// <expr> || true --> true
if (cst.booleanValue() == true) {
this.left.generateCode(currentScope, codeStream, false);
if (valueRequired) codeStream.iconst_1();
} else {
// <expr>|| false --> <expr>
this.left.generateCode(currentScope, codeStream, valueRequired);
}
if (this.mergedInitStateIndex != -1) {
codeStream.removeNotDefinitelyAssignedVariables(currentScope, this.mergedInitStateIndex);
}
codeStream.generateImplicitConversion(this.implicitConversion);
codeStream.recordPositionsFrom(pc, this.sourceStart);
return;
}
BranchLabel trueLabel = new BranchLabel(codeStream), endLabel;
cst = this.left.optimizedBooleanConstant();
boolean leftIsConst = cst != Constant.NotAConstant;
boolean leftIsTrue = leftIsConst && cst.booleanValue() == true;
cst = this.right.optimizedBooleanConstant();
boolean rightIsConst = cst != Constant.NotAConstant;
boolean rightIsTrue = rightIsConst && cst.booleanValue() == true;
generateOperands:
{
if (leftIsConst) {
this.left.generateCode(currentScope, codeStream, false);
if (leftIsTrue) {
break generateOperands; // no need to generate right operand
}
} else {
this.left.generateOptimizedBoolean(currentScope, codeStream, trueLabel, null, true);
// need value, e.g. if (a == 1 || ((b = 2) > 0)) {} -> shouldn't initialize 'b' if a==1
}
if (this.rightInitStateIndex != -1) {
codeStream.addDefinitelyAssignedVariables(currentScope, this.rightInitStateIndex);
}
if (rightIsConst) {
this.right.generateCode(currentScope, codeStream, false);
} else {
this.right.generateOptimizedBoolean(
currentScope, codeStream, trueLabel, null, valueRequired);
}
}
if (this.mergedInitStateIndex != -1) {
codeStream.removeNotDefinitelyAssignedVariables(currentScope, this.mergedInitStateIndex);
}
/*
* improving code gen for such a case: boolean b = i < 0 || true since
* the label has never been used, we have the inlined value on the
* stack.
*/
if (valueRequired) {
if (leftIsConst && leftIsTrue) {
codeStream.iconst_1();
codeStream.recordPositionsFrom(codeStream.position, this.left.sourceEnd);
} else {
if (rightIsConst && rightIsTrue) {
codeStream.iconst_1();
codeStream.recordPositionsFrom(codeStream.position, this.left.sourceEnd);
} else {
codeStream.iconst_0();
}
if (trueLabel.forwardReferenceCount() > 0) {
if ((this.bits & IsReturnedValue) != 0) {
codeStream.generateImplicitConversion(this.implicitConversion);
codeStream.generateReturnBytecode(this);
trueLabel.place();
codeStream.iconst_1();
} else {
codeStream.goto_(endLabel = new BranchLabel(codeStream));
codeStream.decrStackSize(1);
trueLabel.place();
codeStream.iconst_1();
endLabel.place();
}
} else {
trueLabel.place();
}
}
codeStream.generateImplicitConversion(this.implicitConversion);
codeStream.recordPositionsFrom(codeStream.position, this.sourceEnd);
} else {
trueLabel.place();
}
}
/** Boolean operator code generation Optimized operations are: || */
public void generateOptimizedBoolean(
BlockScope currentScope,
CodeStream codeStream,
BranchLabel trueLabel,
BranchLabel falseLabel,
boolean valueRequired) {
if (this.constant != Constant.NotAConstant) {
super.generateOptimizedBoolean(
currentScope, codeStream, trueLabel, falseLabel, valueRequired);
return;
}
// <expr> || false --> <expr>
Constant cst = this.right.constant;
if (cst != Constant.NotAConstant && cst.booleanValue() == false) {
int pc = codeStream.position;
this.left.generateOptimizedBoolean(
currentScope, codeStream, trueLabel, falseLabel, valueRequired);
if (this.mergedInitStateIndex != -1) {
codeStream.removeNotDefinitelyAssignedVariables(currentScope, this.mergedInitStateIndex);
}
codeStream.recordPositionsFrom(pc, this.sourceStart);
return;
}
cst = this.left.optimizedBooleanConstant();
boolean leftIsConst = cst != Constant.NotAConstant;
boolean leftIsTrue = leftIsConst && cst.booleanValue() == true;
cst = this.right.optimizedBooleanConstant();
boolean rightIsConst = cst != Constant.NotAConstant;
boolean rightIsTrue = rightIsConst && cst.booleanValue() == true;
// default case
generateOperands:
{
if (falseLabel == null) {
if (trueLabel != null) {
// implicit falling through the FALSE case
this.left.generateOptimizedBoolean(
currentScope, codeStream, trueLabel, null, !leftIsConst);
// need value, e.g. if (a == 1 || ((b = 2) > 0)) {} -> shouldn't initialize 'b' if a==1
if (leftIsTrue) {
if (valueRequired) codeStream.goto_(trueLabel);
codeStream.recordPositionsFrom(codeStream.position, this.left.sourceEnd);
break generateOperands; // no need to generate right operand
}
if (this.rightInitStateIndex != -1) {
codeStream.addDefinitelyAssignedVariables(currentScope, this.rightInitStateIndex);
}
this.right.generateOptimizedBoolean(
currentScope, codeStream, trueLabel, null, valueRequired && !rightIsConst);
if (valueRequired && rightIsTrue) {
codeStream.goto_(trueLabel);
codeStream.recordPositionsFrom(codeStream.position, this.sourceEnd);
}
}
} else {
// implicit falling through the TRUE case
if (trueLabel == null) {
BranchLabel internalTrueLabel = new BranchLabel(codeStream);
this.left.generateOptimizedBoolean(
currentScope, codeStream, internalTrueLabel, null, !leftIsConst);
// need value, e.g. if (a == 1 || ((b = 2) > 0)) {} -> shouldn't initialize 'b' if a==1
if (leftIsTrue) {
internalTrueLabel.place();
break generateOperands; // no need to generate right operand
}
if (this.rightInitStateIndex != -1) {
codeStream.addDefinitelyAssignedVariables(currentScope, this.rightInitStateIndex);
}
this.right.generateOptimizedBoolean(
currentScope, codeStream, null, falseLabel, valueRequired && !rightIsConst);
int pc = codeStream.position;
if (valueRequired && rightIsConst && !rightIsTrue) {
codeStream.goto_(falseLabel);
codeStream.recordPositionsFrom(pc, this.sourceEnd);
}
internalTrueLabel.place();
} else {
// no implicit fall through TRUE/FALSE --> should never occur
}
}
}
if (this.mergedInitStateIndex != -1) {
codeStream.removeNotDefinitelyAssignedVariables(currentScope, this.mergedInitStateIndex);
}
}