/** Checks if the given function matches the criteria for an inlinable function. */
private boolean isCandidateFunction(Function fn) {
// Don't inline exported functions.
String fnName = fn.getName();
if (compiler.getCodingConvention().isExported(fnName)) {
// TODO(johnlenz): Should we allow internal references to be inlined?
// An exported name can be replaced externally, any inlined instance
// would not reflect this change.
// To allow inlining we need to be able to distinguish between exports
// that are used in a read-only fashion and those that can be replaced
// by external definitions.
return false;
}
// Don't inline this special function
if (RenameProperties.RENAME_PROPERTY_FUNCTION_NAME.equals(fnName)) {
return false;
}
// Don't inline if we are specializing and the function can't be fixed up
if (specializationState != null
&& !specializationState.canFixupFunction(fn.getFunctionNode())) {
return false;
}
Node fnNode = fn.getFunctionNode();
return injector.doesFunctionMeetMinimumRequirements(fnName, fnNode);
}
@Override
public void process(Node externs, Node root) {
Preconditions.checkState(compiler.getLifeCycleStage().isNormalized());
NodeTraversal.traverseEs6(compiler, root, new FindCandidateFunctions());
if (fns.isEmpty()) {
return; // Nothing left to do.
}
NodeTraversal.traverseEs6(compiler, root, new FindCandidatesReferences(fns, anonFns));
trimCandidatesNotMeetingMinimumRequirements();
if (fns.isEmpty()) {
return; // Nothing left to do.
}
// Store the set of function names eligible for inlining and use this to
// prevent function names from being moved into temporaries during
// expression decomposition. If this movement were allowed it would prevent
// the Inline callback from finding the function calls.
//
// This pass already assumes these are constants, so this is safe for anyone
// using function inlining.
//
Set<String> fnNames = new HashSet<>(fns.keySet());
injector.setKnownConstants(fnNames);
trimCandidatesUsingOnCost();
if (fns.isEmpty()) {
return; // Nothing left to do.
}
resolveInlineConflicts();
decomposeExpressions();
NodeTraversal.traverseEs6(compiler, root, new CallVisitor(fns, anonFns, new Inline(injector)));
removeInlinedFunctions();
}
/** @return Whether inlining the function reduces code size. */
private boolean inliningLowersCost(FunctionState fs) {
return injector.inliningLowersCost(
fs.getModule(),
fs.getFn().getFunctionNode(),
fs.getReferences(),
fs.getNamesToAlias(),
fs.canRemove(),
fs.getReferencesThis());
}
/**
* For any call-site that needs it, prepare the call-site for inlining by rewriting the containing
* expression.
*/
private void decomposeExpressions() {
for (FunctionState fs : fns.values()) {
if (fs.canInline()) {
for (Reference ref : fs.getReferences()) {
if (ref.requiresDecomposition) {
injector.maybePrepareCall(ref);
}
}
}
}
}
/** Inline a function into the call site. */
private void inlineFunction(NodeTraversal t, Reference ref, FunctionState fs) {
Function fn = fs.getFn();
String fnName = fn.getName();
Node fnNode = fs.getSafeFnNode();
Node newExpr = injector.inline(ref, fnName, fnNode);
if (!newExpr.isEquivalentTo(ref.callNode)) {
t.getCompiler().reportChangeToEnclosingScope(newExpr);
}
t.getCompiler().addToDebugLog("Inlined function: " + fn.getName());
}
/**
* Updates the FunctionState object for the given function. Checks if the given function matches
* the criteria for an inlinable function.
*/
private void maybeAddFunction(Function fn, JSModule module) {
String name = fn.getName();
FunctionState fs = getOrCreateFunctionState(name);
// TODO(johnlenz): Maybe "smarten" FunctionState by adding this logic
// to it?
// If the function has multiple definitions, don't inline it.
if (fs.hasExistingFunctionDefinition()) {
fs.setInline(false);
return;
}
Node fnNode = fn.getFunctionNode();
if (enforceMaxSizeAfterInlining
&& !isAlwaysInlinable(fnNode)
&& maxSizeAfterInlining <= NodeUtil.countAstSizeUpToLimit(fnNode, maxSizeAfterInlining)) {
fs.setInline(false);
return;
}
// verify the function hasn't already been marked as "don't inline"
if (fs.canInline()) {
// store it for use when inlining.
fs.setFn(fn);
if (FunctionInjector.isDirectCallNodeReplacementPossible(fn.getFunctionNode())) {
fs.inlineDirectly(true);
}
// verify the function meets all the requirements.
// TODO(johnlenz): Minimum requirement checks are about 5% of the
// run-time cost of this pass.
if (!isCandidateFunction(fn)) {
// It doesn't meet the requirements.
fs.setInline(false);
}
// Set the module and gather names that need temporaries.
if (fs.canInline()) {
fs.setModule(module);
Set<String> namesToAlias = FunctionArgumentInjector.findModifiedParameters(fnNode);
if (!namesToAlias.isEmpty()) {
fs.inlineDirectly(false);
fs.setNamesToAlias(namesToAlias);
}
Node block = NodeUtil.getFunctionBody(fnNode);
if (NodeUtil.referencesThis(block)) {
fs.setReferencesThis(true);
}
if (NodeUtil.containsFunction(block)) {
fs.setHasInnerFunctions(true);
// If there are inner functions, we can inline into global scope
// if there are no local vars or named functions.
// TODO(johnlenz): this can be improved by looking at the possible
// values for locals. If there are simple values, or constants
// we could still inline.
if (!assumeMinimumCapture && hasLocalNames(fnNode)) {
fs.setInline(false);
}
}
}
// Check if block inlining is allowed.
if (fs.canInline() && !fs.canInlineDirectly()) {
if (!blockFunctionInliningEnabled) {
fs.setInline(false);
}
}
}
}
