/** Determine which, if any, of the supported types the call site is. */
private CallSiteType classifyCallSite(Node callNode) {
Node parent = callNode.getParent();
Node grandParent = parent.getParent();
// Verify the call site:
if (NodeUtil.isExprCall(parent)) {
// This is a simple call? Example: "foo();".
return CallSiteType.SIMPLE_CALL;
} else if (NodeUtil.isExprAssign(grandParent)
&& !NodeUtil.isLhs(callNode, parent)
&& parent.getFirstChild().getType() == Token.NAME
&& !NodeUtil.isConstantName(parent.getFirstChild())) {
// This is a simple assignment. Example: "x = foo();"
return CallSiteType.SIMPLE_ASSIGNMENT;
} else if (parent.getType() == Token.NAME
&& !NodeUtil.isConstantName(parent)
&& grandParent.getType() == Token.VAR
&& grandParent.hasOneChild()) {
// This is a var declaration. Example: "var x = foo();"
// TODO(johnlenz): Should we be checking for constants on the
// left-hand-side of the assignments (and handling them as EXPRESSION?
return CallSiteType.VAR_DECL_SIMPLE_ASSIGNMENT;
} else {
Node expressionRoot = ExpressionDecomposer.findExpressionRoot(callNode);
if (expressionRoot != null) {
ExpressionDecomposer decomposer =
new ExpressionDecomposer(compiler, safeNameIdSupplier, knownConstants);
DecompositionType type = decomposer.canExposeExpression(callNode);
if (type == DecompositionType.MOVABLE) {
return CallSiteType.EXPRESSION;
} else if (type == DecompositionType.DECOMPOSABLE) {
return CallSiteType.DECOMPOSABLE_EXPRESSION;
} else {
Preconditions.checkState(type == DecompositionType.UNDECOMPOSABLE);
}
}
}
return CallSiteType.UNSUPPORTED;
}
/**
* Inline a function which fulfills the requirements of canInlineReferenceAsStatementBlock into
* the call site, replacing the parent expression.
*/
private Node inlineFunction(Node callNode, Node fnNode, String fnName) {
Node parent = callNode.getParent();
Node grandParent = parent.getParent();
// TODO(johnlenz): Consider storing the callSite classification in the
// reference object and passing it in here.
CallSiteType callSiteType = classifyCallSite(callNode);
Preconditions.checkArgument(callSiteType != CallSiteType.UNSUPPORTED);
// Store the name for the result. This will be used to
// replace "return expr" statements with "resultName = expr"
// to replace
String resultName = null;
boolean needsDefaultReturnResult = true;
switch (callSiteType) {
case SIMPLE_ASSIGNMENT:
resultName = parent.getFirstChild().getString();
break;
case VAR_DECL_SIMPLE_ASSIGNMENT:
resultName = parent.getString();
break;
case SIMPLE_CALL:
resultName = null; // "foo()" doesn't need a result.
needsDefaultReturnResult = false;
break;
case EXPRESSION:
resultName = getUniqueResultName();
needsDefaultReturnResult = false; // The intermediary result already
// has the default value.
break;
case DECOMPOSABLE_EXPRESSION:
throw new IllegalStateException(
"Decomposable expressions must decomposed before inlining.");
default:
throw new IllegalStateException("Unexpected call site type.");
}
boolean isCallInLoop = NodeUtil.isWithinLoop(callNode);
FunctionToBlockMutator mutator = new FunctionToBlockMutator(compiler, this.safeNameIdSupplier);
Node newBlock =
mutator.mutate(
fnName, fnNode, callNode, resultName, needsDefaultReturnResult, isCallInLoop);
// TODO(nicksantos): Create a common mutation function that
// can replace either a VAR name assignment, assignment expression or
// a EXPR_RESULT.
Node greatGrandParent = grandParent.getParent();
switch (callSiteType) {
case VAR_DECL_SIMPLE_ASSIGNMENT:
// Remove the call from the name node.
parent.removeChild(parent.getFirstChild());
Preconditions.checkState(parent.getFirstChild() == null);
// Add the call, after the VAR.
greatGrandParent.addChildAfter(newBlock, grandParent);
break;
case SIMPLE_ASSIGNMENT:
// The assignment is now part of the inline function so
// replace it completely.
Preconditions.checkState(NodeUtil.isExpressionNode(grandParent));
greatGrandParent.replaceChild(grandParent, newBlock);
break;
case SIMPLE_CALL:
// If nothing is looking at the result just replace the call.
Preconditions.checkState(NodeUtil.isExpressionNode(parent));
grandParent.replaceChild(parent, newBlock);
break;
case EXPRESSION:
// TODO(johnlenz): Maybe change this so that movable and decomposable
// expressions are handled the same way: The call is moved and
// then handled by one the three basic cases, rather than
// introducing a new case.
Node injectionPoint = ExpressionDecomposer.findInjectionPoint(callNode);
Preconditions.checkNotNull(injectionPoint);
Node injectionPointParent = injectionPoint.getParent();
Preconditions.checkNotNull(injectionPointParent);
Preconditions.checkState(NodeUtil.isStatementBlock(injectionPointParent));
// Declare the intermediate result name.
newBlock.addChildrenToFront(
NodeUtil.newVarNode(resultName, null).copyInformationFromForTree(callNode));
// Inline the function before the selected injection point (before
// the call).
injectionPointParent.addChildBefore(newBlock, injectionPoint);
// Replace the call site with a reference to the intermediate
// result name.
parent.replaceChild(callNode, Node.newString(Token.NAME, resultName));
break;
default:
throw new IllegalStateException("Unexpected call site type.");
}
return newBlock;
}
