/**
* Optimizations for OP_convert_i: convert_i, convert_i -> convert_i coerce_i, convert_i ->
* coerce_i OP_bitand, convert_i -> OP_bitand OP_bitor, convert_i -> OP_bitor OP_bitxor, convert_i
* -> OP_bitxor lshift, convert_i -> lshift rshift, convert_i -> rshift add_i, convert_i -> add_i
* subtract_i, convert_i -> subtract_i increment_i, convert_i -> increment_i decrement_i,
* convert_i -> decrement_i multiply_i, convert_i -> multiply_i pushbyte, convert_i -> pushbyte
* pushshort, convert_i -> pushshort pushint, convert_i -> pushint li8, convert_i -> li8 li16,
* convert_i -> li16 li32, convert_i -> li32 sxi1, convert_i -> sxi1 sxi8, convert_i -> sxi8
* sxi16, convert_i -> sxi16
*
* @param i The convert_b instruction
*/
private void op_convert_i(InstructionInfo i) {
InstructionInfo prev = previous(1);
switch (prev.getOpcode()) {
case OP_convert_i:
case OP_coerce_i:
case OP_bitand:
case OP_bitor:
case OP_bitxor:
case OP_lshift:
case OP_rshift:
case OP_add_i:
case OP_subtract_i:
case OP_increment_i:
case OP_decrement_i:
case OP_multiply_i:
case OP_pushbyte:
case OP_pushshort:
case OP_pushint:
case OP_li8:
case OP_li16:
case OP_li32:
case OP_sxi1:
case OP_sxi8:
case OP_sxi16:
{
// result is already an int, just erase the op_convert_i
delete(0);
break;
}
default:
{
// nothing to do - instruction has already been added
}
}
}
/**
* Optimizations for OP_convert_b: equals, convert_b -> equals strictequals, convert_b ->
* strictequals not, convert_b -> not greaterthan, convert_b -> greaterthan lessthan, convert_b ->
* lessthan greaterequals, convert_b -> greaterequals lessequals, convert_b -> lessequals istype,
* convert_b -> istype istypelate, convert_b -> istypelate instanceof, convert_b -> instanceof
* deleteproperty, convert_d -> deleteproperty in, convert_d -> in convert_b, convert_b ->
* convert_b pushtrue, convert_b -> pushtrue pushfalse, convert_b -> pushfalse
*
* @param i The convert_b instruction
*/
private void op_convert_b(InstructionInfo i) {
InstructionInfo prev = previous(1);
switch (prev.getOpcode()) {
case OP_equals:
case OP_strictequals:
case OP_not:
case OP_greaterthan:
case OP_lessthan:
case OP_greaterequals:
case OP_lessequals:
case OP_istype:
case OP_istypelate:
case OP_instanceof:
case OP_deleteproperty:
case OP_in:
case OP_convert_b:
case OP_pushtrue:
case OP_pushfalse:
{
// result is already a boolean, just erase the op_convert_b
delete(0);
break;
}
default:
{
// nothing to do - instruction has already been added
}
}
}
/**
* Optimizations for OP_returnvoid: returnvoid, returnvoid -> returnvoid getlocal0, pushscope,
* returnvoid -> returnvoid (insn without side effect), returnvoid -> returnvoid
*/
private void op_returnvoid(InstructionInfo i) {
InstructionInfo prev = previous(1);
switch (prev.getOpcode()) {
case OP_returnvoid:
{
delete(0);
break;
}
// Any instruction without side effects that
// the CG is likely to generate can go here.
case OP_pop:
{
replace(1, i.getInstruction());
break;
}
case OP_pushscope:
{
if (previous(2).getOpcode() == OP_getlocal0)
// Trivial function.
replace(2, i.getInstruction());
break;
}
default:
{
// nothing to do, instruction has already been added
}
}
}
/**
* Optimizations for OP_getproperty: findpropstrict name, getproperty name -> getlex name
*
* @param i the getproperty instruction
*/
private void op_getproperty(InstructionInfo i) {
InstructionInfo prev = previous(1);
switch (prev.getOpcode()) {
case OP_findpropstrict:
{
// can optimize findpropstrict, followed by getprop of the same name
// if there are any instructions btwn the findpropstrict and getprop (such as to compute a
// runtime
// multiname), we won't match this pattern
if (i.getOperand(0).equals(prev.getOperand(0)))
replace(
1, InstructionFactory.createModifiedInstruction(OP_getlex, prev.getInstruction()));
break;
}
}
}
/**
* Optimizations for OP_convert_i: convert_u, convert_u -> convert_u pushuint, convert_u ->
* pushuint
*
* @param i The convert_b instruction
*/
private void op_convert_u(InstructionInfo i) {
InstructionInfo prev = previous(1);
switch (prev.getOpcode()) {
case OP_convert_u:
case OP_pushuint:
{
// result is already a uint, just erase the op_convert_u
delete(0);
break;
}
default:
{
// nothing to do - instruction has already been added
}
}
}
/**
* Optimizations for OP_convert_s: coerce_s, convert_s -> coerce_s convert_s, convert_s ->
* convert_s pushstring, convert_s -> pushstring typeof, convert_s -> typeof
*
* @param i The convert_b instruction
*/
private void op_convert_s(InstructionInfo i) {
InstructionInfo prev = previous(1);
switch (prev.getOpcode()) {
case OP_coerce_s:
case OP_convert_s:
case OP_pushstring:
case OP_typeof:
{
// result is already a String, just erase the op_convert_s
delete(0);
break;
}
default:
{
// nothing to do - instruction has already been added
}
}
}
/**
* Helper method to perform optimizations around jumps when we get a labeling operation. Shared
* with labelNext and labelCurrent methods
*
* @param l the Label object passed into the label operation
* @param kind what kind of labeling operation are we doing (labelNext or labelCurrent)
*/
private void jumpOptimizations(Label l, LabelKind kind) {
// Need to start looking at different indexes for label current vs. label next
// this is because for a label next, the next instruction won't have come in yet.
int idx = kind == LabelKind.LABEL_CURRENT ? 1 : 0;
InstructionInfo prev = previous(idx);
switch (prev.getOpcode()) {
case OP_jump:
{
InstructionInfo prev2 = previous(idx + 1);
Instruction insn = prev2.getInstruction();
if (insn != null && insn.isBranch() && insn.getTarget() == l) {
// If the previous instructions were an if that jumped here, and it
// only jumped over another jump, then we can invert the if instruction
// and save a jump
// iffalse L1, jump L2, L1 -> iftrue L2, L1
Instruction newIf = invertIf(prev2, prev);
if (newIf != null) {
if (kind == LabelKind.LABEL_CURRENT) {
// labelCurrent, so we need to preserve the last instruction
Instruction[] newInsns = {newIf, previous(0).getInstruction()};
replace(idx + 1, newInsns);
} else {
// labelNext so we can just delete the last instruction
replace(idx + 1, newIf);
}
}
}
// If the previous instruction was a jump, and it just jumped
// to the next instruction, then we can remove the jump and just fall
// through
// jump L1, L1 -> L1
else if (prev.getOperand(0) == l) {
if (kind == LabelKind.LABEL_NEXT)
// can just delete the jump because we don't have the next instruction yet
delete(idx);
else
// replace the jump with its target
replace(idx, previous(0).getInstruction());
}
}
}
}
/**
* evaluates an instruction and determines if it will result in true or false on TOS.
*
* @param i is an instruction to analyze
* @return whether TOS is true, false, or not known
*/
private static ConstantBoolean isTrueInstructionInfo(InstructionInfo i) {
ConstantBoolean ret = ConstantBoolean.DONT_KNOW;
switch (i.getOpcode()) {
case OP_pushtrue:
ret = ConstantBoolean.TRUE;
break;
case OP_pushfalse:
ret = ConstantBoolean.FALSE;
break;
case OP_pushbyte:
{
int value = i.getImmediate();
assert value >= 0;
ret = ECMASupport.toBoolean(value) ? ConstantBoolean.TRUE : ConstantBoolean.FALSE;
break;
}
case OP_pushint:
{
int value = (Integer) i.getOperand(0);
ret = ECMASupport.toBoolean(value) ? ConstantBoolean.TRUE : ConstantBoolean.FALSE;
break;
}
case OP_pushuint:
{
long value = (Long) i.getOperand(0);
ret = ECMASupport.toBoolean(value) ? ConstantBoolean.TRUE : ConstantBoolean.FALSE;
break;
}
case OP_pushstring:
{
String value = i.getOperand(0).toString();
ret = ECMASupport.toBoolean(value) ? ConstantBoolean.TRUE : ConstantBoolean.FALSE;
break;
}
case OP_pushnull:
ret = ConstantBoolean.FALSE;
break;
}
return ret;
}
/** Optimizations for OP_getlocal: setlocal N, getlocal N -> dup, setlocal N */
private void OP_getlocal(InstructionInfo i) {
InstructionInfo prev = previous(1);
InstructionInfo cur = previous(0);
switch (prev.getOpcode()) {
case OP_setlocal:
{
if (cur.getInstruction().getImmediate() != prev.getInstruction().getImmediate())
break; // set,get of different locals
Instruction[] newInsns = {
InstructionFactory.getInstruction(OP_dup), prev.getInstruction()
};
replace(1, newInsns);
break;
}
default:
{
// nothing to do, instruction has already been added
}
}
}
/**
* Optimizations for OP_convert_d: convert_d, convert_d -> convert_d pushbyte n, convert_d ->
* pushdouble n pushint n, convert_d -> pushdouble n pushuint n, convert_d -> pushdouble n
* pushdouble n, convert_d -> pushdouble n pushnan, convert_d -> pushnan lf32, convert_d -> lf32
* lf64, convert_d -> lf64
*
* @param i The convert_d instruction
*/
private void op_convert_d(InstructionInfo i) {
InstructionInfo prev = previous(1);
switch (prev.getOpcode()) {
case OP_pushbyte:
{
// replace pushbyte, convert d with pushdouble - should be faster
replace(
1,
InstructionFactory.getInstruction(
OP_pushdouble, new Double(convertByteImmediateToDouble(prev.getImmediate()))));
break;
}
case OP_pushint:
case OP_pushuint:
{
// replace pushint , convert d with pushdouble - should be faster
replace(
1,
InstructionFactory.getInstruction(
OP_pushdouble, new Double(((Number) prev.getOperand(0)).doubleValue())));
break;
}
case OP_pushdouble:
case OP_pushnan:
case OP_lf32:
case OP_lf64:
case OP_convert_d:
{
// result is already a double, just erase the op_convert_d
delete(0);
break;
}
default:
{
// nothing to do - instruction has already been added
}
}
}
/** Optimizations for OP_pop: callprop, pop -> callpropvoid callsuper, pop -> callsupervoid */
private void op_pop(InstructionInfo i) {
InstructionInfo prev = previous(1);
switch (prev.getOpcode()) {
case OP_callproperty:
{
replace(
1,
InstructionFactory.createModifiedInstruction(OP_callpropvoid, prev.getInstruction()));
break;
}
case OP_callsuper:
{
replace(
1,
InstructionFactory.createModifiedInstruction(
OP_callsupervoid, prev.getInstruction()));
break;
}
default:
{
// nothing to do, instruction has already been added
}
}
}
/**
* Optimizations for OP_iftrue: convert_b, iftrue -> iftrue equals, iftrue -> ifeq strictequals,
* iftrue -> ifstricteq lessthen, iftrue -> iflt lessequals, iftrue -> ifle greaterthan, iftrue ->
* ifgt greaterequals, iftrue -> ifge pushfalse, iftrue -> jump pushtrue, iftrue -> nothing
* strictequals, not, iftrue -> ifstrictne equals, not, iftrue -> ifne lessthan, not, iftrue ->
* ifnlt lessequals, not, iftrue -> ifnle greaterthan, not, iftrue -> ifngt greaterequals,
* not,iftrue -> ifnge not, iftrue -> iffalse
*
* @param i the iftrue instruction
*/
private void op_iftrue(InstructionInfo i) {
InstructionInfo prev = previous(1);
switch (isTrueInstructionInfo(prev)) {
case FALSE:
delete(1);
return;
case TRUE:
replace(1, InstructionFactory.createModifiedInstruction(OP_jump, i.getInstruction()));
return;
case DONT_KNOW:
break; // continue on if we don't know it's a constant boolean
default:
assert false;
}
switch (prev.getOpcode()) {
case OP_convert_b:
{
replace(1, i.getInstruction());
break;
}
case OP_equals:
{
replace(1, InstructionFactory.createModifiedInstruction(OP_ifeq, i.getInstruction()));
break;
}
case OP_strictequals:
{
replace(
1, InstructionFactory.createModifiedInstruction(OP_ifstricteq, i.getInstruction()));
break;
}
case OP_lessthan:
{
replace(1, InstructionFactory.createModifiedInstruction(OP_iflt, i.getInstruction()));
break;
}
case OP_lessequals:
{
replace(1, InstructionFactory.createModifiedInstruction(OP_ifle, i.getInstruction()));
break;
}
case OP_greaterthan:
{
replace(1, InstructionFactory.createModifiedInstruction(OP_ifgt, i.getInstruction()));
break;
}
case OP_greaterequals:
{
replace(1, InstructionFactory.createModifiedInstruction(OP_ifge, i.getInstruction()));
break;
}
case OP_not:
{
InstructionInfo prev2 = previous(2);
switch (prev2.getOpcode()) {
case OP_strictequals:
{
replace(
2,
InstructionFactory.createModifiedInstruction(
OP_ifstrictne, i.getInstruction()));
break;
}
case OP_equals:
{
replace(
2, InstructionFactory.createModifiedInstruction(OP_ifne, i.getInstruction()));
break;
}
case OP_lessthan:
{
replace(
2, InstructionFactory.createModifiedInstruction(OP_ifnlt, i.getInstruction()));
break;
}
case OP_lessequals:
{
replace(
2, InstructionFactory.createModifiedInstruction(OP_ifnle, i.getInstruction()));
break;
}
case OP_greaterthan:
{
replace(
2, InstructionFactory.createModifiedInstruction(OP_ifngt, i.getInstruction()));
break;
}
case OP_greaterequals:
{
replace(
2, InstructionFactory.createModifiedInstruction(OP_ifnge, i.getInstruction()));
break;
}
default:
{
replace(
1,
InstructionFactory.createModifiedInstruction(OP_iffalse, i.getInstruction()));
break;
}
}
break;
}
default:
// nothing to do, instruction was already added
}
}
/**
* Optimizations for OP_iffalse: convert_b, iffalse -> iffalse equals, iffalse -> ifne
* strictequals, iffalse -> strictne lessthen, iffalse -> ifnlt lessequals, iffalse -> ifnle
* greaterthan, iffalse -> ifngt greaterequals, iffalse -> ifnge pushfalse, iffalse -> jump
* pushtrue, iffalse -> nothing strictequals, not, iffalse -> ifstrictequals equals, not, iffalse
* -> ifeq lessthan, not, iffalse -> iflt lessequals, not, iffalse -> ifle greaterthan, not,
* iffalse -> ifgt greaterequals, not,iffalse -> ifge not, iffalse -> iftrue
*
* @param i the iffalse instruction
*/
private void op_iffalse(InstructionInfo i) {
InstructionInfo prev = previous(1);
// Check if we know what's on the stack. If so, we don't need
// to do a conditional branch
switch (isTrueInstructionInfo(prev)) {
case TRUE:
delete(1); // if we can't branch, just eat the push / iffalse instructions
return;
case FALSE:
replace(1, InstructionFactory.createModifiedInstruction(OP_jump, i.getInstruction()));
// If we always branch, then replace the push / iffalse with an uncontidional jump
return;
case DONT_KNOW:
break; // continue on if we don't know it's a constant boolean
default:
assert false;
}
switch (prev.getOpcode()) {
case OP_convert_b:
{
// replace with just iffalse
replace(1, i.getInstruction());
break;
}
case OP_equals:
{
replace(1, InstructionFactory.createModifiedInstruction(OP_ifne, i.getInstruction()));
break;
}
case OP_strictequals:
{
replace(
1, InstructionFactory.createModifiedInstruction(OP_ifstrictne, i.getInstruction()));
break;
}
case OP_lessthan:
{
replace(1, InstructionFactory.createModifiedInstruction(OP_ifnlt, i.getInstruction()));
break;
}
case OP_lessequals:
{
replace(1, InstructionFactory.createModifiedInstruction(OP_ifnle, i.getInstruction()));
break;
}
case OP_greaterthan:
{
replace(1, InstructionFactory.createModifiedInstruction(OP_ifngt, i.getInstruction()));
break;
}
case OP_greaterequals:
{
replace(1, InstructionFactory.createModifiedInstruction(OP_ifnge, i.getInstruction()));
break;
}
case OP_not:
{
InstructionInfo prev2 = previous(2);
switch (prev2.getOpcode()) {
case OP_strictequals:
{
replace(
2,
InstructionFactory.createModifiedInstruction(
OP_ifstricteq, i.getInstruction()));
break;
}
case OP_equals:
{
replace(
2, InstructionFactory.createModifiedInstruction(OP_ifeq, i.getInstruction()));
break;
}
case OP_lessthan:
{
replace(
2, InstructionFactory.createModifiedInstruction(OP_iflt, i.getInstruction()));
break;
}
case OP_lessequals:
{
replace(
2, InstructionFactory.createModifiedInstruction(OP_ifle, i.getInstruction()));
break;
}
case OP_greaterthan:
{
replace(
2, InstructionFactory.createModifiedInstruction(OP_ifgt, i.getInstruction()));
break;
}
case OP_greaterequals:
{
replace(
2, InstructionFactory.createModifiedInstruction(OP_ifge, i.getInstruction()));
break;
}
default:
{
replace(
1, InstructionFactory.createModifiedInstruction(OP_iftrue, i.getInstruction()));
break;
}
}
break;
}
default:
{
// nothing to do, instruction was already added
}
}
}
/**
* Helper method to invert if expr target jump other-target to if not expr other-target Used to
* optimize some common patterns with if's and jumps
*/
private Instruction invertIf(InstructionInfo oldIf, InstructionInfo oldJump) {
Instruction newIf = null;
switch (oldIf.getOpcode()) {
case OP_ifeq:
{
newIf = InstructionFactory.createModifiedInstruction(OP_ifne, oldJump.getInstruction());
break;
}
case OP_ifstricteq:
{
newIf =
InstructionFactory.createModifiedInstruction(OP_ifstrictne, oldJump.getInstruction());
break;
}
case OP_ifstrictne:
{
newIf =
InstructionFactory.createModifiedInstruction(OP_ifstricteq, oldJump.getInstruction());
break;
}
case OP_ifge:
{
newIf = InstructionFactory.createModifiedInstruction(OP_ifnge, oldJump.getInstruction());
break;
}
case OP_ifgt:
{
newIf = InstructionFactory.createModifiedInstruction(OP_ifngt, oldJump.getInstruction());
break;
}
case OP_iflt:
{
newIf = InstructionFactory.createModifiedInstruction(OP_ifnlt, oldJump.getInstruction());
break;
}
case OP_ifle:
{
newIf = InstructionFactory.createModifiedInstruction(OP_ifnle, oldJump.getInstruction());
break;
}
case OP_ifne:
{
newIf = InstructionFactory.createModifiedInstruction(OP_ifeq, oldJump.getInstruction());
break;
}
case OP_ifnge:
{
newIf = InstructionFactory.createModifiedInstruction(OP_ifge, oldJump.getInstruction());
break;
}
case OP_ifngt:
{
newIf = InstructionFactory.createModifiedInstruction(OP_ifgt, oldJump.getInstruction());
break;
}
case OP_ifnlt:
{
newIf = InstructionFactory.createModifiedInstruction(OP_iflt, oldJump.getInstruction());
break;
}
case OP_ifnle:
{
newIf = InstructionFactory.createModifiedInstruction(OP_ifle, oldJump.getInstruction());
break;
}
case OP_iftrue:
{
newIf =
InstructionFactory.createModifiedInstruction(OP_iffalse, oldJump.getInstruction());
break;
}
case OP_iffalse:
{
newIf = InstructionFactory.createModifiedInstruction(OP_iftrue, oldJump.getInstruction());
break;
}
}
return newIf;
}
/**
* Perform optimizations on the instructions currently held in the window. This is so we don't do
* the optimizations until we are sure a particular instruction was or was not the target of a
* jump. If it was a target, then we don't do the optimizations as we don't have enough
* information to determine all the ways control might flow to that instruction.
*/
private void processPreviousInstructions() {
InstructionInfo last = previous(0);
InstructionInfo secondLast = previous(1);
// Check if we have a labelCurrent on the last instruction, or a labelNext on the previous
// instruction
if (last.getLabelCurrents().isEmpty() && secondLast.getLabelNexts().isEmpty()) {
switch (last.getOpcode()) {
case OP_convert_b:
{
op_convert_b(last);
break;
}
case OP_convert_d:
{
op_convert_d(last);
break;
}
case OP_convert_i:
{
op_convert_i(last);
break;
}
case OP_convert_u:
{
op_convert_u(last);
break;
}
case OP_convert_s:
{
op_convert_s(last);
break;
}
case OP_getproperty:
{
op_getproperty(last);
break;
}
case OP_iffalse:
{
op_iffalse(last);
break;
}
case OP_iftrue:
{
op_iftrue(last);
break;
}
case OP_pop:
{
op_pop(last);
break;
}
case OP_nop:
{
delete(0);
break;
}
case OP_getlocal:
{
OP_getlocal(last);
break;
}
case OP_returnvoid:
{
op_returnvoid(last);
break;
}
default:
{
break;
}
}
}
}
