void propagate(Node& node)
{
if (!node.shouldGenerate())
return;
NodeType op = node.op();
NodeFlags flags = node.flags() & NodeBackPropMask;
#if DFG_ENABLE(DEBUG_PROPAGATION_VERBOSE)
dataLog(" %s @%u: %s ", Graph::opName(op), m_compileIndex, nodeFlagsAsString(flags));
#endif
bool changed = false;
switch (op) {
case JSConstant:
case WeakJSConstant: {
changed |= setPrediction(speculationFromValue(m_graph.valueOfJSConstant(m_compileIndex)));
break;
}
case GetLocal: {
VariableAccessData* variableAccessData = node.variableAccessData();
SpeculatedType prediction = variableAccessData->prediction();
if (prediction)
changed |= mergePrediction(prediction);
changed |= variableAccessData->mergeFlags(flags);
break;
}
case SetLocal: {
VariableAccessData* variableAccessData = node.variableAccessData();
changed |= variableAccessData->predict(m_graph[node.child1()].prediction());
changed |= m_graph[node.child1()].mergeFlags(variableAccessData->flags());
break;
}
case Flush: {
// Make sure that the analysis knows that flushed locals escape.
VariableAccessData* variableAccessData = node.variableAccessData();
changed |= variableAccessData->mergeFlags(NodeUsedAsValue);
break;
}
case BitAnd:
case BitOr:
case BitXor:
case BitRShift:
case BitLShift:
case BitURShift: {
changed |= setPrediction(SpecInt32);
flags |= NodeUsedAsInt;
flags &= ~(NodeUsedAsNumber | NodeNeedsNegZero);
changed |= m_graph[node.child1()].mergeFlags(flags);
changed |= m_graph[node.child2()].mergeFlags(flags);
break;
}
case ValueToInt32: {
changed |= setPrediction(SpecInt32);
flags |= NodeUsedAsInt;
flags &= ~(NodeUsedAsNumber | NodeNeedsNegZero);
changed |= m_graph[node.child1()].mergeFlags(flags);
break;
}
case ArrayPop: {
changed |= mergePrediction(node.getHeapPrediction());
changed |= mergeDefaultFlags(node);
break;
}
case ArrayPush: {
changed |= mergePrediction(node.getHeapPrediction());
changed |= m_graph[node.child1()].mergeFlags(NodeUsedAsValue);
changed |= m_graph[node.child2()].mergeFlags(NodeUsedAsValue);
break;
}
case RegExpExec:
case RegExpTest: {
changed |= mergePrediction(node.getHeapPrediction());
changed |= mergeDefaultFlags(node);
break;
}
case StringCharCodeAt: {
changed |= mergePrediction(SpecInt32);
changed |= m_graph[node.child1()].mergeFlags(NodeUsedAsValue);
changed |= m_graph[node.child2()].mergeFlags(NodeUsedAsNumber | NodeUsedAsInt);
break;
}
case ArithMod: {
SpeculatedType left = m_graph[node.child1()].prediction();
SpeculatedType right = m_graph[node.child2()].prediction();
if (left && right) {
if (isInt32Speculation(mergeSpeculations(left, right))
&& nodeCanSpeculateInteger(node.arithNodeFlags()))
changed |= mergePrediction(SpecInt32);
else
changed |= mergePrediction(SpecDouble);
}
flags |= NodeUsedAsValue;
changed |= m_graph[node.child1()].mergeFlags(flags);
changed |= m_graph[node.child2()].mergeFlags(flags);
break;
}
case UInt32ToNumber: {
if (nodeCanSpeculateInteger(node.arithNodeFlags()))
changed |= mergePrediction(SpecInt32);
else
changed |= mergePrediction(SpecNumber);
changed |= m_graph[node.child1()].mergeFlags(flags);
break;
}
case ValueAdd: {
SpeculatedType left = m_graph[node.child1()].prediction();
SpeculatedType right = m_graph[node.child2()].prediction();
if (left && right) {
if (isNumberSpeculation(left) && isNumberSpeculation(right)) {
if (m_graph.addShouldSpeculateInteger(node))
changed |= mergePrediction(SpecInt32);
else
changed |= mergePrediction(speculatedDoubleTypeForPredictions(left, right));
} else if (!(left & SpecNumber) || !(right & SpecNumber)) {
// left or right is definitely something other than a number.
changed |= mergePrediction(SpecString);
} else
changed |= mergePrediction(SpecString | SpecInt32 | SpecDouble);
}
if (isNotNegZero(node.child1().index()) || isNotNegZero(node.child2().index()))
flags &= ~NodeNeedsNegZero;
changed |= m_graph[node.child1()].mergeFlags(flags);
changed |= m_graph[node.child2()].mergeFlags(flags);
break;
}
case ArithAdd: {
SpeculatedType left = m_graph[node.child1()].prediction();
SpeculatedType right = m_graph[node.child2()].prediction();
if (left && right) {
if (m_graph.addShouldSpeculateInteger(node))
changed |= mergePrediction(SpecInt32);
else
changed |= mergePrediction(speculatedDoubleTypeForPredictions(left, right));
}
if (isNotNegZero(node.child1().index()) || isNotNegZero(node.child2().index()))
flags &= ~NodeNeedsNegZero;
changed |= m_graph[node.child1()].mergeFlags(flags);
changed |= m_graph[node.child2()].mergeFlags(flags);
break;
}
case ArithSub: {
SpeculatedType left = m_graph[node.child1()].prediction();
SpeculatedType right = m_graph[node.child2()].prediction();
if (left && right) {
if (m_graph.addShouldSpeculateInteger(node))
changed |= mergePrediction(SpecInt32);
else
changed |= mergePrediction(speculatedDoubleTypeForPredictions(left, right));
}
if (isNotZero(node.child1().index()) || isNotZero(node.child2().index()))
flags &= ~NodeNeedsNegZero;
changed |= m_graph[node.child1()].mergeFlags(flags);
changed |= m_graph[node.child2()].mergeFlags(flags);
break;
}
case ArithNegate:
if (m_graph[node.child1()].prediction()) {
if (m_graph.negateShouldSpeculateInteger(node))
changed |= mergePrediction(SpecInt32);
else
changed |= mergePrediction(speculatedDoubleTypeForPrediction(m_graph[node.child1()].prediction()));
}
changed |= m_graph[node.child1()].mergeFlags(flags);
break;
case ArithMin:
case ArithMax: {
SpeculatedType left = m_graph[node.child1()].prediction();
SpeculatedType right = m_graph[node.child2()].prediction();
if (left && right) {
if (isInt32Speculation(mergeSpeculations(left, right))
&& nodeCanSpeculateInteger(node.arithNodeFlags()))
changed |= mergePrediction(SpecInt32);
else
changed |= mergePrediction(speculatedDoubleTypeForPredictions(left, right));
}
flags |= NodeUsedAsNumber;
changed |= m_graph[node.child1()].mergeFlags(flags);
changed |= m_graph[node.child2()].mergeFlags(flags);
break;
}
case ArithMul: {
SpeculatedType left = m_graph[node.child1()].prediction();
SpeculatedType right = m_graph[node.child2()].prediction();
if (left && right) {
if (m_graph.mulShouldSpeculateInteger(node))
changed |= mergePrediction(SpecInt32);
else
changed |= mergePrediction(speculatedDoubleTypeForPredictions(left, right));
}
// As soon as a multiply happens, we can easily end up in the part
// of the double domain where the point at which you do truncation
// can change the outcome. So, ArithMul always checks for overflow
// no matter what, and always forces its inputs to check as well.
flags |= NodeUsedAsNumber | NodeNeedsNegZero;
changed |= m_graph[node.child1()].mergeFlags(flags);
changed |= m_graph[node.child2()].mergeFlags(flags);
break;
}
case ArithDiv: {
SpeculatedType left = m_graph[node.child1()].prediction();
SpeculatedType right = m_graph[node.child2()].prediction();
if (left && right) {
if (isInt32Speculation(mergeSpeculations(left, right))
&& nodeCanSpeculateInteger(node.arithNodeFlags()))
changed |= mergePrediction(SpecInt32);
else
changed |= mergePrediction(SpecDouble);
}
// As soon as a multiply happens, we can easily end up in the part
// of the double domain where the point at which you do truncation
// can change the outcome. So, ArithMul always checks for overflow
// no matter what, and always forces its inputs to check as well.
flags |= NodeUsedAsNumber | NodeNeedsNegZero;
changed |= m_graph[node.child1()].mergeFlags(flags);
changed |= m_graph[node.child2()].mergeFlags(flags);
break;
}
case ArithSqrt: {
changed |= setPrediction(SpecDouble);
changed |= m_graph[node.child1()].mergeFlags(flags | NodeUsedAsValue);
break;
}
case ArithAbs: {
SpeculatedType child = m_graph[node.child1()].prediction();
if (nodeCanSpeculateInteger(node.arithNodeFlags()))
changed |= mergePrediction(child);
else
changed |= setPrediction(speculatedDoubleTypeForPrediction(child));
flags &= ~NodeNeedsNegZero;
changed |= m_graph[node.child1()].mergeFlags(flags);
break;
}
case LogicalNot:
case CompareLess:
case CompareLessEq:
case CompareGreater:
case CompareGreaterEq:
case CompareEq:
case CompareStrictEq:
case InstanceOf:
case IsUndefined:
case IsBoolean:
case IsNumber:
case IsString:
case IsObject:
case IsFunction: {
changed |= setPrediction(SpecBoolean);
changed |= mergeDefaultFlags(node);
break;
}
case GetById: {
changed |= mergePrediction(node.getHeapPrediction());
changed |= mergeDefaultFlags(node);
break;
}
case GetByIdFlush:
changed |= mergePrediction(node.getHeapPrediction());
changed |= mergeDefaultFlags(node);
break;
case GetByVal: {
if (m_graph[node.child1()].shouldSpeculateFloat32Array()
|| m_graph[node.child1()].shouldSpeculateFloat64Array())
changed |= mergePrediction(SpecDouble);
else
changed |= mergePrediction(node.getHeapPrediction());
changed |= m_graph[node.child1()].mergeFlags(NodeUsedAsValue);
changed |= m_graph[node.child2()].mergeFlags(NodeUsedAsNumber | NodeUsedAsInt);
break;
}
case GetMyArgumentByValSafe: {
changed |= mergePrediction(node.getHeapPrediction());
changed |= m_graph[node.child1()].mergeFlags(NodeUsedAsNumber | NodeUsedAsInt);
break;
}
case GetMyArgumentsLengthSafe: {
changed |= setPrediction(SpecInt32);
break;
}
case GetScopeRegisters:
case GetButterfly:
case GetIndexedPropertyStorage:
case AllocatePropertyStorage:
case ReallocatePropertyStorage: {
changed |= setPrediction(SpecOther);
changed |= mergeDefaultFlags(node);
break;
}
case GetByOffset: {
changed |= mergePrediction(node.getHeapPrediction());
changed |= mergeDefaultFlags(node);
break;
}
case Call:
case Construct: {
changed |= mergePrediction(node.getHeapPrediction());
for (unsigned childIdx = node.firstChild();
childIdx < node.firstChild() + node.numChildren();
++childIdx) {
Edge edge = m_graph.m_varArgChildren[childIdx];
changed |= m_graph[edge].mergeFlags(NodeUsedAsValue);
}
break;
}
case ConvertThis: {
SpeculatedType prediction = m_graph[node.child1()].prediction();
if (prediction) {
if (prediction & ~SpecObjectMask) {
prediction &= SpecObjectMask;
prediction = mergeSpeculations(prediction, SpecObjectOther);
}
changed |= mergePrediction(prediction);
}
changed |= mergeDefaultFlags(node);
break;
}
case GetGlobalVar: {
changed |= mergePrediction(node.getHeapPrediction());
break;
}
case PutGlobalVar:
case PutGlobalVarCheck: {
changed |= m_graph[node.child1()].mergeFlags(NodeUsedAsValue);
break;
}
case GetScopedVar:
case Resolve:
case ResolveBase:
case ResolveBaseStrictPut:
case ResolveGlobal: {
SpeculatedType prediction = node.getHeapPrediction();
changed |= mergePrediction(prediction);
break;
}
case GetScope: {
changed |= setPrediction(SpecCellOther);
break;
}
case GetCallee: {
changed |= setPrediction(SpecFunction);
break;
}
case CreateThis:
case NewObject: {
changed |= setPrediction(SpecFinalObject);
changed |= mergeDefaultFlags(node);
break;
}
case NewArray: {
changed |= setPrediction(SpecArray);
for (unsigned childIdx = node.firstChild();
childIdx < node.firstChild() + node.numChildren();
++childIdx) {
Edge edge = m_graph.m_varArgChildren[childIdx];
changed |= m_graph[edge].mergeFlags(NodeUsedAsValue);
}
break;
}
case NewArrayWithSize: {
changed |= setPrediction(SpecArray);
changed |= m_graph[node.child1()].mergeFlags(NodeUsedAsNumber | NodeUsedAsInt);
break;
}
case NewArrayBuffer: {
changed |= setPrediction(SpecArray);
break;
}
case NewRegexp: {
changed |= setPrediction(SpecObjectOther);
break;
}
case StringCharAt: {
changed |= setPrediction(SpecString);
changed |= m_graph[node.child1()].mergeFlags(NodeUsedAsValue);
changed |= m_graph[node.child2()].mergeFlags(NodeUsedAsNumber | NodeUsedAsInt);
break;
}
case StrCat: {
changed |= setPrediction(SpecString);
for (unsigned childIdx = node.firstChild();
childIdx < node.firstChild() + node.numChildren();
++childIdx)
changed |= m_graph[m_graph.m_varArgChildren[childIdx]].mergeFlags(NodeUsedAsNumber);
break;
}
case ToPrimitive: {
SpeculatedType child = m_graph[node.child1()].prediction();
if (child) {
if (isObjectSpeculation(child)) {
// I'd love to fold this case into the case below, but I can't, because
// removing SpecObjectMask from something that only has an object
// prediction and nothing else means we have an ill-formed SpeculatedType
// (strong predict-none). This should be killed once we remove all traces
// of static (aka weak) predictions.
changed |= mergePrediction(SpecString);
} else if (child & SpecObjectMask) {
// Objects get turned into strings. So if the input has hints of objectness,
// the output will have hinsts of stringiness.
changed |= mergePrediction(
mergeSpeculations(child & ~SpecObjectMask, SpecString));
} else
changed |= mergePrediction(child);
}
changed |= m_graph[node.child1()].mergeFlags(flags);
break;
}
case CreateActivation: {
changed |= setPrediction(SpecObjectOther);
break;
}
case CreateArguments: {
// At this stage we don't try to predict whether the arguments are ours or
// someone else's. We could, but we don't, yet.
changed |= setPrediction(SpecArguments);
break;
}
case NewFunction:
case NewFunctionNoCheck:
case NewFunctionExpression: {
changed |= setPrediction(SpecFunction);
break;
}
case PutByValAlias:
case GetArrayLength:
case Int32ToDouble:
case DoubleAsInt32:
case GetLocalUnlinked:
case GetMyArgumentsLength:
case GetMyArgumentByVal:
case PhantomPutStructure:
case PhantomArguments:
case CheckArray:
case Arrayify: {
// This node should never be visible at this stage of compilation. It is
// inserted by fixup(), which follows this phase.
ASSERT_NOT_REACHED();
break;
}
case PutByVal:
changed |= m_graph[m_graph.varArgChild(node, 0)].mergeFlags(NodeUsedAsValue);
changed |= m_graph[m_graph.varArgChild(node, 1)].mergeFlags(NodeUsedAsNumber | NodeUsedAsInt);
changed |= m_graph[m_graph.varArgChild(node, 2)].mergeFlags(NodeUsedAsValue);
break;
case PutScopedVar:
case Return:
case Throw:
changed |= m_graph[node.child1()].mergeFlags(NodeUsedAsValue);
break;
case PutById:
case PutByIdDirect:
changed |= m_graph[node.child1()].mergeFlags(NodeUsedAsValue);
changed |= m_graph[node.child2()].mergeFlags(NodeUsedAsValue);
break;
case PutByOffset:
changed |= m_graph[node.child1()].mergeFlags(NodeUsedAsValue);
changed |= m_graph[node.child3()].mergeFlags(NodeUsedAsValue);
break;
case Phi:
break;
#ifndef NDEBUG
// These get ignored because they don't return anything.
case DFG::Jump:
case Branch:
case Breakpoint:
case CheckHasInstance:
case ThrowReferenceError:
case ForceOSRExit:
case SetArgument:
case CheckStructure:
case ForwardCheckStructure:
case StructureTransitionWatchpoint:
case ForwardStructureTransitionWatchpoint:
case CheckFunction:
case PutStructure:
case TearOffActivation:
case TearOffArguments:
case CheckNumber:
case CheckArgumentsNotCreated:
case GlobalVarWatchpoint:
case GarbageValue:
changed |= mergeDefaultFlags(node);
break;
// These gets ignored because it doesn't do anything.
case Phantom:
case InlineStart:
case Nop:
break;
case LastNodeType:
ASSERT_NOT_REACHED();
break;
#else
default:
changed |= mergeDefaultFlags(node);
break;
#endif
}
#if DFG_ENABLE(DEBUG_PROPAGATION_VERBOSE)
dataLog("%s\n", speculationToString(m_graph[m_compileIndex].prediction()));
#endif
m_changed |= changed;
}
void propagate(Node* node)
{
NodeFlags flags = node->flags() & NodeBytecodeBackPropMask;
switch (node->op()) {
case GetLocal: {
VariableAccessData* variableAccessData = node->variableAccessData();
flags &= ~NodeBytecodeUsesAsInt; // We don't care about cross-block uses-as-int.
m_changed |= variableAccessData->mergeFlags(flags);
break;
}
case SetLocal: {
VariableAccessData* variableAccessData = node->variableAccessData();
if (!variableAccessData->isLoadedFrom())
break;
flags = variableAccessData->flags();
RELEASE_ASSERT(!(flags & ~NodeBytecodeBackPropMask));
flags |= NodeBytecodeUsesAsNumber; // Account for the fact that control flow may cause overflows that our modeling can't handle.
node->child1()->mergeFlags(flags);
break;
}
case Flush: {
VariableAccessData* variableAccessData = node->variableAccessData();
m_changed |= variableAccessData->mergeFlags(NodeBytecodeUsesAsValue);
break;
}
case MovHint:
case Check:
break;
case BitAnd:
case BitOr:
case BitXor:
case BitRShift:
case BitLShift:
case BitURShift:
case ArithIMul: {
flags |= NodeBytecodeUsesAsInt;
flags &= ~(NodeBytecodeUsesAsNumber | NodeBytecodeNeedsNegZero | NodeBytecodeUsesAsOther);
flags &= ~NodeBytecodeUsesAsArrayIndex;
node->child1()->mergeFlags(flags);
node->child2()->mergeFlags(flags);
break;
}
case StringCharCodeAt: {
node->child1()->mergeFlags(NodeBytecodeUsesAsValue);
node->child2()->mergeFlags(NodeBytecodeUsesAsValue | NodeBytecodeUsesAsInt | NodeBytecodeUsesAsArrayIndex);
break;
}
case UInt32ToNumber: {
node->child1()->mergeFlags(flags);
break;
}
case ValueAdd: {
if (isNotNegZero(node->child1().node()) || isNotNegZero(node->child2().node()))
flags &= ~NodeBytecodeNeedsNegZero;
if (node->child1()->hasNumberResult() || node->child2()->hasNumberResult())
flags &= ~NodeBytecodeUsesAsOther;
if (!isWithinPowerOfTwo<32>(node->child1()) && !isWithinPowerOfTwo<32>(node->child2()))
flags |= NodeBytecodeUsesAsNumber;
if (!m_allowNestedOverflowingAdditions)
flags |= NodeBytecodeUsesAsNumber;
node->child1()->mergeFlags(flags);
node->child2()->mergeFlags(flags);
break;
}
case ArithAdd: {
flags &= ~NodeBytecodeUsesAsOther;
if (isNotNegZero(node->child1().node()) || isNotNegZero(node->child2().node()))
flags &= ~NodeBytecodeNeedsNegZero;
if (!isWithinPowerOfTwo<32>(node->child1()) && !isWithinPowerOfTwo<32>(node->child2()))
flags |= NodeBytecodeUsesAsNumber;
if (!m_allowNestedOverflowingAdditions)
flags |= NodeBytecodeUsesAsNumber;
node->child1()->mergeFlags(flags);
node->child2()->mergeFlags(flags);
break;
}
case ArithClz32: {
flags &= ~(NodeBytecodeUsesAsNumber | NodeBytecodeNeedsNegZero | NodeBytecodeUsesAsOther | ~NodeBytecodeUsesAsArrayIndex);
flags |= NodeBytecodeUsesAsInt;
node->child1()->mergeFlags(flags);
break;
}
case ArithSub: {
flags &= ~NodeBytecodeUsesAsOther;
if (isNotNegZero(node->child1().node()) || isNotPosZero(node->child2().node()))
flags &= ~NodeBytecodeNeedsNegZero;
if (!isWithinPowerOfTwo<32>(node->child1()) && !isWithinPowerOfTwo<32>(node->child2()))
flags |= NodeBytecodeUsesAsNumber;
if (!m_allowNestedOverflowingAdditions)
flags |= NodeBytecodeUsesAsNumber;
node->child1()->mergeFlags(flags);
node->child2()->mergeFlags(flags);
break;
}
case ArithNegate: {
flags &= ~NodeBytecodeUsesAsOther;
node->child1()->mergeFlags(flags);
break;
}
case ArithMul: {
// As soon as a multiply happens, we can easily end up in the part
// of the double domain where the point at which you do truncation
// can change the outcome. So, ArithMul always forces its inputs to
// check for overflow. Additionally, it will have to check for overflow
// itself unless we can prove that there is no way for the values
// produced to cause double rounding.
if (!isWithinPowerOfTwo<22>(node->child1().node())
&& !isWithinPowerOfTwo<22>(node->child2().node()))
flags |= NodeBytecodeUsesAsNumber;
node->mergeFlags(flags);
flags |= NodeBytecodeUsesAsNumber | NodeBytecodeNeedsNegZero;
flags &= ~NodeBytecodeUsesAsOther;
node->child1()->mergeFlags(flags);
node->child2()->mergeFlags(flags);
break;
}
case ArithDiv: {
flags |= NodeBytecodeUsesAsNumber | NodeBytecodeNeedsNegZero;
flags &= ~NodeBytecodeUsesAsOther;
node->child1()->mergeFlags(flags);
node->child2()->mergeFlags(flags);
break;
}
case ArithMod: {
flags |= NodeBytecodeUsesAsNumber;
flags &= ~NodeBytecodeUsesAsOther;
node->child1()->mergeFlags(flags);
node->child2()->mergeFlags(flags & ~NodeBytecodeNeedsNegZero);
break;
}
case GetByVal: {
node->child1()->mergeFlags(NodeBytecodeUsesAsValue);
node->child2()->mergeFlags(NodeBytecodeUsesAsNumber | NodeBytecodeUsesAsOther | NodeBytecodeUsesAsInt | NodeBytecodeUsesAsArrayIndex);
break;
}
case NewArrayWithSize: {
node->child1()->mergeFlags(NodeBytecodeUsesAsValue | NodeBytecodeUsesAsInt | NodeBytecodeUsesAsArrayIndex);
break;
}
case NewTypedArray: {
// Negative zero is not observable. NaN versus undefined are only observable
// in that you would get a different exception message. So, like, whatever: we
// claim here that NaN v. undefined is observable.
node->child1()->mergeFlags(NodeBytecodeUsesAsInt | NodeBytecodeUsesAsNumber | NodeBytecodeUsesAsOther | NodeBytecodeUsesAsArrayIndex);
break;
}
case StringCharAt: {
node->child1()->mergeFlags(NodeBytecodeUsesAsValue);
node->child2()->mergeFlags(NodeBytecodeUsesAsValue | NodeBytecodeUsesAsInt | NodeBytecodeUsesAsArrayIndex);
break;
}
case ToString:
case CallStringConstructor: {
node->child1()->mergeFlags(NodeBytecodeUsesAsNumber | NodeBytecodeUsesAsOther);
break;
}
case ToPrimitive:
case ToNumber: {
node->child1()->mergeFlags(flags);
break;
}
case PutByValDirect:
case PutByVal: {
m_graph.varArgChild(node, 0)->mergeFlags(NodeBytecodeUsesAsValue);
m_graph.varArgChild(node, 1)->mergeFlags(NodeBytecodeUsesAsNumber | NodeBytecodeUsesAsOther | NodeBytecodeUsesAsInt | NodeBytecodeUsesAsArrayIndex);
m_graph.varArgChild(node, 2)->mergeFlags(NodeBytecodeUsesAsValue);
break;
}
case Switch: {
SwitchData* data = node->switchData();
switch (data->kind) {
case SwitchImm:
// We don't need NodeBytecodeNeedsNegZero because if the cases are all integers
// then -0 and 0 are treated the same. We don't need NodeBytecodeUsesAsOther
// because if all of the cases are integers then NaN and undefined are
// treated the same (i.e. they will take default).
node->child1()->mergeFlags(NodeBytecodeUsesAsNumber | NodeBytecodeUsesAsInt);
break;
case SwitchChar: {
// We don't need NodeBytecodeNeedsNegZero because if the cases are all strings
// then -0 and 0 are treated the same. We don't need NodeBytecodeUsesAsOther
// because if all of the cases are single-character strings then NaN
// and undefined are treated the same (i.e. they will take default).
node->child1()->mergeFlags(NodeBytecodeUsesAsNumber);
break;
}
case SwitchString:
// We don't need NodeBytecodeNeedsNegZero because if the cases are all strings
// then -0 and 0 are treated the same.
node->child1()->mergeFlags(NodeBytecodeUsesAsNumber | NodeBytecodeUsesAsOther);
break;
case SwitchCell:
// There is currently no point to being clever here since this is used for switching
// on objects.
mergeDefaultFlags(node);
break;
}
break;
}
case Identity:
// This would be trivial to handle but we just assert that we cannot see these yet.
RELEASE_ASSERT_NOT_REACHED();
break;
// Note: ArithSqrt, ArithUnary and other math intrinsics don't have special
// rules in here because they are always followed by Phantoms to signify that if the
// method call speculation fails, the bytecode may use the arguments in arbitrary ways.
// This corresponds to that possibility of someone doing something like:
// Math.sin = function(x) { doArbitraryThingsTo(x); }
default:
mergeDefaultFlags(node);
break;
}
}