@Override
public void visit(NodeTraversal t, Node n, Node parent) {
switch (n.getType()) {
// Function calls
case Token.CALL:
Node child = n.getFirstChild();
String name = null;
// NOTE: The normalization pass insures that local names do not
// collide with global names.
if (child.isName()) {
name = child.getString();
} else if (child.isFunction()) {
name = anonFunctionMap.get(child);
} else if (NodeUtil.isFunctionObjectCall(n)) {
Preconditions.checkState(NodeUtil.isGet(child));
Node fnIdentifingNode = child.getFirstChild();
if (fnIdentifingNode.isName()) {
name = fnIdentifingNode.getString();
} else if (fnIdentifingNode.isFunction()) {
name = anonFunctionMap.get(fnIdentifingNode);
}
}
if (name != null) {
FunctionState fs = functionMap.get(name);
// Only visit call-sites for functions that can be inlined.
if (fs != null) {
callback.visitCallSite(t, n, fs);
}
}
break;
}
}
/**
* Returns the nth argument node given a usage site for a direct function call or for a
* func.call() node.
*/
private static Node getArgumentForCallOrNewOrDotCall(UseSite site, final int argIndex) {
int adjustedArgIndex = argIndex;
Node parent = site.node.getParent();
if (NodeUtil.isFunctionObjectCall(parent)) {
adjustedArgIndex++;
}
return NodeUtil.getArgumentForCallOrNew(parent, adjustedArgIndex);
}
/**
* Determines whether a function can be inlined at a particular call site. There are several
* criteria that the function and reference must hold in order for the functions to be inlined: 1)
* If a call's arguments have side effects, the corresponding argument in the function must only
* be referenced once. For instance, this will not be inlined:
*
* <pre>
* function foo(a) { return a + a }
* x = foo(i++);
* </pre>
*/
private CanInlineResult canInlineReferenceDirectly(Node callNode, Node fnNode) {
if (!isDirectCallNodeReplacementPossible(fnNode)) {
return CanInlineResult.NO;
}
Node block = fnNode.getLastChild();
// CALL NODE: [ NAME, ARG1, ARG2, ... ]
Node cArg = callNode.getFirstChild().getNext();
// Functions called via 'call' and 'apply' have a this-object as
// the first parameter, but this is not part of the called function's
// parameter list.
if (callNode.getFirstChild().getType() != Token.NAME) {
if (NodeUtil.isFunctionObjectCall(callNode)) {
// TODO(johnlenz): Support replace this with a value.
Preconditions.checkNotNull(cArg);
Preconditions.checkState(cArg.getType() == Token.THIS);
cArg = cArg.getNext();
} else {
// ".apply" call should be filtered before this.
Preconditions.checkState(!NodeUtil.isFunctionObjectApply(callNode));
}
}
// FUNCTION NODE -> LP NODE: [ ARG1, ARG2, ... ]
Node fnParam = NodeUtil.getFnParameters(fnNode).getFirstChild();
while (cArg != null || fnParam != null) {
// For each named parameter check if a mutable argument use more than one.
if (fnParam != null) {
if (cArg != null) {
// Check for arguments that are evaluated more than once.
// Note: Unlike block inlining, there it is not possible that a
// parameter reference will be in a loop.
if (NodeUtil.mayEffectMutableState(cArg)
&& NodeUtil.getNameReferenceCount(block, fnParam.getString()) > 1) {
return CanInlineResult.NO;
}
}
// Move to the next name.
fnParam = fnParam.getNext();
}
// For every call argument check for side-effects, even if there
// isn't a named parameter to match.
if (cArg != null) {
if (NodeUtil.mayHaveSideEffects(cArg)) {
return CanInlineResult.NO;
}
cArg = cArg.getNext();
}
}
return CanInlineResult.YES;
}
/**
* Only ".call" calls and direct calls to functions are supported.
*
* @param callNode The call evaluate.
* @return Whether the call is of a type that is supported.
*/
private boolean isSupportedCallType(Node callNode) {
if (callNode.getFirstChild().getType() != Token.NAME) {
if (NodeUtil.isFunctionObjectCall(callNode)) {
Node thisValue = callNode.getFirstChild().getNext();
if (thisValue == null || thisValue.getType() != Token.THIS) {
return false;
}
} else if (NodeUtil.isFunctionObjectApply(callNode)) {
return false;
}
}
return true;
}
/**
* @return Whether the definitionSite represents a function whose call signature can be
* modified.
*/
private boolean canChangeSignature(Node function) {
Definition definition = getFunctionDefinition(function);
CodingConvention convention = compiler.getCodingConvention();
Preconditions.checkState(!definition.isExtern());
Collection<UseSite> useSites = defFinder.getUseSites(definition);
for (UseSite site : useSites) {
Node parent = site.node.getParent();
// This was a use site removed by something else before we run.
// 1. By another pass before us which means the definition graph is
// no updated properly.
// 2. By the continuations algorithm above.
if (parent == null) {
continue; // Ignore it.
}
// Ignore references within goog.inherits calls.
if (NodeUtil.isCall(parent) && convention.getClassesDefinedByCall(parent) != null) {
continue;
}
// Accessing the property directly prevents rewrite.
if (!SimpleDefinitionFinder.isCallOrNewSite(site)) {
if (!(NodeUtil.isGetProp(parent) && NodeUtil.isFunctionObjectCall(parent.getParent()))) {
return false;
}
}
if (NodeUtil.isFunctionObjectApply(parent)) {
return false;
}
// TODO(johnlenz): support specialization
// Multiple definitions prevent rewrite.
// Attempt to validate the state of the simple definition finder.
Node nameNode = site.node;
Collection<Definition> singleSiteDefinitions =
defFinder.getDefinitionsReferencedAt(nameNode);
Preconditions.checkState(singleSiteDefinitions.size() == 1);
Preconditions.checkState(singleSiteDefinitions.contains(definition));
}
return true;
}
/**
* @param t The traversal use to reach the call site.
* @param callNode The CALL node.
* @param fnNode The function to evaluate for inlining.
* @param needAliases A set of function parameter names that can not be used without aliasing.
* Returned by getUnsafeParameterNames().
* @param mode Inlining mode to be used.
* @param referencesThis Whether fnNode contains references to its this object.
* @param containsFunctions Whether fnNode contains inner functions.
* @return Whether the inlining can occur.
*/
CanInlineResult canInlineReferenceToFunction(
NodeTraversal t,
Node callNode,
Node fnNode,
Set<String> needAliases,
InliningMode mode,
boolean referencesThis,
boolean containsFunctions) {
// TODO(johnlenz): This function takes too many parameter, without
// context. Modify the API to take a structure describing the function.
// Allow direct function calls or "fn.call" style calls.
if (!isSupportedCallType(callNode)) {
return CanInlineResult.NO;
}
// Limit where functions that contain functions can be inline. Introducing
// an inner function into another function can capture a variable and cause
// a memory leak. This isn't a problem in the global scope as those values
// last until explicitly cleared.
if (containsFunctions && !t.inGlobalScope()) {
// TODO(johnlenz): Allow inlining into any scope without local names or
// inner functions.
return CanInlineResult.NO;
}
// TODO(johnlenz): Add support for 'apply'
if (referencesThis && !NodeUtil.isFunctionObjectCall(callNode)) {
// TODO(johnlenz): Allow 'this' references to be replaced with a
// global 'this' object.
return CanInlineResult.NO;
}
if (mode == InliningMode.DIRECT) {
return canInlineReferenceDirectly(callNode, fnNode);
} else {
return canInlineReferenceAsStatementBlock(t, callNode, fnNode, needAliases);
}
}
/**
* Find function expressions that are called directly in the form of
* (function(a,b,...){...})(a,b,...) or (function(a,b,...){...}).call(this,a,b, ...)
*/
public void findFunctionExpressions(NodeTraversal t, Node n) {
switch (n.getType()) {
// Functions expressions in the form of:
// (function(){})();
case Token.CALL:
Node fnNode = null;
if (n.getFirstChild().isFunction()) {
fnNode = n.getFirstChild();
} else if (NodeUtil.isFunctionObjectCall(n)) {
Node fnIdentifingNode = n.getFirstChild().getFirstChild();
if (fnIdentifingNode.isFunction()) {
fnNode = fnIdentifingNode;
}
}
// If a interesting function was discovered, add it.
if (fnNode != null) {
Function fn = new FunctionExpression(fnNode, callsSeen++);
maybeAddFunction(fn, t.getModule());
anonFns.put(fnNode, fn.getName());
}
break;
}
}
