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/*
* Copyright 2006 The Closure Compiler Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.javascript.jscomp;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Joiner;
import com.google.common.base.MoreObjects;
import com.google.common.collect.HashBasedTable;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;
import com.google.common.collect.Table;
import com.google.javascript.jscomp.CodingConvention.SubclassRelationship;
import com.google.javascript.jscomp.modules.ModuleMap;
import com.google.javascript.jscomp.modules.ModuleMetadataMap.ModuleMetadata;
import com.google.javascript.rhino.IR;
import com.google.javascript.rhino.JSDocInfo;
import com.google.javascript.rhino.Node;
import com.google.javascript.rhino.QualifiedName;
import com.google.javascript.rhino.StaticRef;
import com.google.javascript.rhino.StaticScope;
import com.google.javascript.rhino.StaticSlot;
import com.google.javascript.rhino.StaticSourceFile;
import com.google.javascript.rhino.StaticSymbolTable;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import javax.annotation.Nullable;
/**
* Builds a namespace of all qualified names whose root is in the global scope or a module, plus an
* index of all references to those global names.
*
* When used as a StaticScope this class acts like a single parentless global scope. The module
* references are currently only accessible by {@link #getNameFromModule(ModuleMetadata, String)},
* as many use cases only care about global names. (This may change as module rewriting is moved
* later in compilation). Module tracking also only occurs when {@link
* com.google.javascript.jscomp.modules.ModuleMapCreator} has run.
*
*
The namespace can be updated as the AST is changed. Removing names or references should be
* done by the methods on Name. Adding new names should be done with {@link #scanNewNodes}.
*/
class GlobalNamespace
implements StaticScope, StaticSymbolTable {
private final AbstractCompiler compiler;
private final boolean enableImplicityAliasedValues;
private final Node root;
private final Node externsRoot;
private final Node globalRoot = IR.root();
private final LinkedHashMap spreadSiblingCache = new LinkedHashMap<>();
private SourceKind sourceKind;
private Scope externsScope;
private boolean generated = false;
private static final QualifiedName GOOG_PROVIDE = QualifiedName.of("goog.provide");
enum SourceKind {
EXTERN,
TYPE_SUMMARY,
CODE;
static SourceKind fromScriptNode(Node n) {
if (!n.isFromExterns()) {
return CODE;
} else if (NodeUtil.isFromTypeSummary(n)) {
return TYPE_SUMMARY;
} else {
return EXTERN;
}
}
}
/**
* Each reference has an index in post-order. Notice that some nodes are represented by 2 Ref
* objects, so this index is not necessarily unique.
*/
private int currentPreOrderIndex = 0;
/** Global namespace tree */
private final List globalNames = new ArrayList<>();
/** Maps names (e.g. "a.b.c") to nodes in the global namespace tree */
private final Map nameMap = new HashMap<>();
/** Maps names (e.g. "a.b.c") and MODULE_BODY nodes to Names in that module */
private final Table nameMapByModule = HashBasedTable.create();
/**
* Creates an instance that may emit warnings when building the namespace.
*
* @param compiler The AbstractCompiler, for reporting code changes
* @param root The root of the rest of the code to build a namespace for.
*/
GlobalNamespace(AbstractCompiler compiler, Node root) {
this(compiler, null, root);
}
/**
* Creates an instance that may emit warnings when building the namespace.
*
* @param compiler The AbstractCompiler, for reporting code changes
* @param externsRoot The root of the externs to build a namespace for. If this is null, externs
* and properties defined on extern types will not be included in the global namespace. If
* non-null, it allows user-defined function on extern types to be included in the global
* namespace. E.g. String.foo.
* @param root The root of the rest of the code to build a namespace for.
*/
GlobalNamespace(AbstractCompiler compiler, Node externsRoot, Node root) {
this.compiler = compiler;
this.externsRoot = externsRoot;
this.root = root;
this.enableImplicityAliasedValues = compiler.getOptions().getAssumeStaticInheritanceRequired();
}
boolean hasExternsRoot() {
return externsRoot != null;
}
@Override
public Node getRootNode() {
return root.getParent();
}
/**
* Returns the root node of the scope in which the root of a qualified name is declared, or null.
*
* @param name A variable name (e.g. "a")
* @param s The scope in which the name is referenced
* @return The root node of the scope in which this is defined, or null if this is undeclared.
*/
private Node getRootNode(String name, Scope s) {
name = getTopVarName(name);
Var v = s.getVar(name);
if (v == null && externsScope != null) {
v = externsScope.getVar(name);
}
if (v == null) {
Name providedName = nameMap.get(name);
return providedName != null && providedName.isProvided ? globalRoot : null;
}
return v.isLocal() ? v.getScopeRoot() : globalRoot;
}
@Override
public StaticScope getParentScope() {
return null;
}
@Override
public Name getSlot(String name) {
return getOwnSlot(name);
}
@Override
public Name getOwnSlot(String name) {
ensureGenerated();
return nameMap.get(name);
}
@Override
public Iterable getReferences(Name slot) {
ensureGenerated();
return Collections.unmodifiableCollection(slot.getRefs());
}
@Override
public StaticScope getScope(Name slot) {
return this;
}
@Override
public Collection getAllSymbols() {
ensureGenerated();
return Collections.unmodifiableCollection(getNameIndex().values());
}
private void ensureGenerated() {
if (!generated) {
process();
}
}
/**
* Gets a list of the roots of the forest of the global names, where the roots are the top-level
* names.
*/
List getNameForest() {
ensureGenerated();
return globalNames;
}
/**
* Gets an index of all the global names, indexed by full qualified name (as in "a", "a.b.c",
* etc.).
*/
Map getNameIndex() {
ensureGenerated();
return nameMap;
}
/**
* A simple data class that contains the information necessary to inspect a node for changes to
* the global namespace.
*/
static class AstChange {
final JSModule module;
final Scope scope;
final Node node;
AstChange(JSModule module, Scope scope, Node node) {
this.module = module;
this.scope = scope;
this.node = node;
}
@Override
public boolean equals(Object obj) {
if (obj instanceof AstChange) {
AstChange other = (AstChange) obj;
return Objects.equals(this.module, other.module)
&& Objects.equals(this.scope, other.scope)
&& Objects.equals(this.node, other.node);
}
return false;
}
@Override
public int hashCode() {
return Objects.hash(this.module, this.scope, this.node);
}
}
/**
* If the client adds new nodes to the AST, scan these new nodes to see if they've added any
* references to the global namespace.
*
* @param newNodes New nodes to check.
*/
void scanNewNodes(Set newNodes) {
BuildGlobalNamespace builder = new BuildGlobalNamespace();
for (AstChange info : newNodes) {
if (!info.node.isQualifiedName() && !NodeUtil.mayBeObjectLitKey(info.node)) {
continue;
}
scanFromNode(builder, info.module, info.scope, info.node);
}
}
private void scanFromNode(BuildGlobalNamespace builder, JSModule module, Scope scope, Node n) {
// Check affected parent nodes first.
Node parent = n.getParent();
if ((n.isName() || n.isGetProp()) && parent.isGetProp()) {
// e.g. when replacing "my.alias.prop" with "foo.bar.prop"
// we want also want to visit "foo.bar.prop", since that's a new global qname we are now
// referencing.
scanFromNode(builder, module, scope, n.getParent());
} else if (n.getPrevious() != null && n.getPrevious().isObjectPattern()) {
// e.g. if we change `const {x} = bar` to `const {x} = foo`, add a new reference to `foo.x`
// attached to the STRING_KEY `x`
Node pattern = n.getPrevious();
for (Node key : pattern.children()) {
if (key.isStringKey()) {
scanFromNode(builder, module, scope, key);
}
}
}
builder.collect(module, scope, n);
}
/** Builds the namespace lazily. */
private void process() {
if (hasExternsRoot()) {
sourceKind = SourceKind.EXTERN;
NodeTraversal.traverse(compiler, externsRoot, new BuildGlobalNamespace());
}
sourceKind = SourceKind.CODE;
NodeTraversal.traverse(compiler, root, new BuildGlobalNamespace());
generated = true;
externsScope = null;
}
/**
* Gets the top variable name from a possibly namespaced name.
*
* @param name A variable or qualified property name (e.g. "a" or "a.b.c.d")
* @return The top variable name (e.g. "a")
*/
private static String getTopVarName(String name) {
int firstDotIndex = name.indexOf('.');
return firstDotIndex == -1 ? name : name.substring(0, firstDotIndex);
}
@Nullable
Name getNameFromModule(ModuleMetadata moduleMetadata, String name) {
checkNotNull(moduleMetadata);
checkNotNull(name);
ensureGenerated();
return nameMapByModule.get(moduleMetadata, name);
}
/**
* Returns whether a declaration node, inside an object-literal, has a following OBJECT_SPREAD
* sibling.
*
* This check is implemented using a cache because otherwise it has aggregate {@code O(n^2)}
* performance in terms of the size of an OBJECTLIT. If each declaration checked each sibling
* independently, each sibling would be checked up-to once for each of it's preceeding siblings.
*/
private boolean declarationHasFollowingObjectSpreadSibling(Node declaration) {
checkState(declaration.getParent().isObjectLit(), declaration);
@Nullable Boolean cached = this.spreadSiblingCache.get(declaration);
if (cached != null) {
return cached;
}
/**
* Iterate backward over all children of the object-literal, filling in the cache.
*
*
We iterate the entire literal because we expect to eventually need the result for each of
* them. Additionally, it makes the loop conditions simpler.
*
*
We use a loop rather than recursion to minimize stack depth. Large object-literals were
* the reason caching was added.
*/
boolean toCache = false;
for (Node sibling = declaration.getParent().getLastChild();
sibling != null;
sibling = sibling.getPrevious()) {
if (sibling.isSpread()) {
toCache = true;
}
this.spreadSiblingCache.put(sibling, toCache);
}
return this.spreadSiblingCache.get(declaration);
}
// -------------------------------------------------------------------------
/** Builds a tree representation of the global namespace. Omits prototypes. */
private class BuildGlobalNamespace extends NodeTraversal.AbstractPreOrderCallback {
private Node curModuleRoot = null;
private ModuleMetadata curMetadata = null;
/** Collect the references in pre-order. */
@Override
public boolean shouldTraverse(NodeTraversal t, Node n, Node parent) {
if (hasExternsRoot()) {
if (n == externsRoot) {
// If we are traversing the externs, then we save a pointer to the scope
// generated by them, so that we can do lookups in it later.
externsScope = t.getScope();
} else if (n.isScript()) {
// When checking type-summary files, we want to consider them like normal code
// for some things (like alias inlining) but like externs for other things.
sourceKind = SourceKind.fromScriptNode(n);
}
}
if (n.isModuleBody() || NodeUtil.isBundledGoogModuleScopeRoot(n)) {
setupModuleMetadata(n);
} else if (n.isScript() || NodeUtil.isBundledGoogModuleCall(n)) {
curModuleRoot = null;
curMetadata = null;
}
collect(t.getModule(), t.getScope(), n);
return true;
}
/**
* Initializes the {@link ModuleMetadata} for a goog;.module or ES module
*
* @param moduleRoot either a MODULE_BODY or a goog.loadModule BLOCK.
*/
private void setupModuleMetadata(Node moduleRoot) {
ModuleMap moduleMap = compiler.getModuleMap();
if (moduleMap == null) {
return;
}
curModuleRoot = moduleRoot;
curMetadata =
checkNotNull(
ModuleImportResolver.getModuleFromScopeRoot(moduleMap, compiler, moduleRoot)
.metadata());
if (curMetadata.isGoogModule()) {
getOrCreateName("exports", curMetadata);
}
}
private void collect(JSModule module, Scope scope, Node n) {
Node parent = n.getParent();
String name;
boolean isSet = false;
NameType type = NameType.OTHER;
switch (n.getToken()) {
case GETTER_DEF:
case SETTER_DEF:
case MEMBER_FUNCTION_DEF:
if (parent.isClassMembers() && !n.isStaticMember()) {
return; // Within a class, only static members define global names.
}
name = NodeUtil.getBestLValueName(n);
isSet = true;
type = n.isMemberFunctionDef() ? NameType.FUNCTION : NameType.GET_SET;
break;
case STRING_KEY:
name = null;
if (parent.isObjectLit()) {
name = NodeUtil.getBestLValueName(n);
isSet = true;
} else if (parent.isObjectPattern()) {
name = getNameForObjectPatternKey(n);
// not a set
}
type = getValueType(n.getFirstChild());
break;
case NAME:
// TODO(b/127505242): CAST parents may indicate a set.
// This may be a variable get or set.
switch (parent.getToken()) {
case VAR:
case LET:
case CONST:
isSet = true;
Node rvalue = n.getFirstChild();
type = (rvalue == null) ? NameType.OTHER : getValueType(rvalue);
break;
case ASSIGN:
if (parent.getFirstChild() == n) {
isSet = true;
type = getValueType(n.getNext());
}
break;
case GETPROP:
// This name is nested in a getprop. Return and only create a Ref for the outermost
// getprop in the chain.
return;
case FUNCTION:
Node grandparent = parent.getParent();
if (grandparent == null || NodeUtil.isFunctionExpression(parent)) {
return;
}
isSet = true;
type = NameType.FUNCTION;
break;
case CATCH:
case INC:
case DEC:
isSet = true;
type = NameType.OTHER;
break;
case CLASS:
// The first child is the class name, and the second child is the superclass name.
if (parent.getFirstChild() == n) {
isSet = true;
type = NameType.CLASS;
}
break;
case STRING_KEY:
case ARRAY_PATTERN:
case DEFAULT_VALUE:
case COMPUTED_PROP:
case ITER_REST:
case OBJECT_REST:
// This may be a set.
if (NodeUtil.isLhsByDestructuring(n)) {
isSet = true;
type = NameType.OTHER;
}
break;
case ITER_SPREAD:
case OBJECT_SPREAD:
break; // isSet = false, type = OTHER.
default:
if (NodeUtil.isAssignmentOp(parent) && parent.getFirstChild() == n) {
isSet = true;
type = NameType.OTHER;
}
}
name = n.getString();
break;
case GETPROP:
// TODO(b/117673791): Merge this case with NAME case to fix.
// TODO(b/120303257): Merging this case with the NAME case makes this a breaking bug.
// TODO(b/127505242): CAST parents may indicate a set.
// This may be a namespaced name get or set.
if (parent != null) {
switch (parent.getToken()) {
case ASSIGN:
if (parent.getFirstChild() == n) {
isSet = true;
type = getValueType(n.getNext());
}
break;
case GETPROP:
// This is nested in another getprop. Return and only create a Ref for the outermost
// getprop in the chain.
return;
case INC:
case DEC:
case ITER_SPREAD:
case OBJECT_SPREAD:
break; // isSet = false, type = OTHER.
default:
if (NodeUtil.isAssignmentOp(parent) && parent.getFirstChild() == n) {
isSet = true;
type = NameType.OTHER;
}
}
}
if (!n.isQualifiedName()) {
return;
}
name = n.getQualifiedName();
break;
case CALL:
if (isObjectHasOwnPropertyCall(n)) {
String qname = n.getFirstFirstChild().getQualifiedName();
Name globalName = getOrCreateName(qname, curMetadata);
globalName.usedHasOwnProperty = true;
} else if (parent.isExprResult()
&& GOOG_PROVIDE.matches(n.getFirstChild())
&& n.getSecondChild().isString()) {
// goog.provide goes through a different code path than regular sets because it can
// create multiple names, e.g. `goog.provide('a.b.c');` creates the global names
// a, a.b, and a.b.c. Other sets only create a single global name.
createNamesFromProvide(n.getSecondChild().getString());
return;
}
return;
default:
return;
}
if (name == null) {
return;
}
Node root = getRootNode(name, scope);
// We are only interested in global and module names.
if (!isTopLevelScopeRoot(root)) {
return;
}
ModuleMetadata nameMetadata = root == globalRoot ? null : curMetadata;
if (isSet) {
// Use the closest hoist scope to select handleSetFromGlobal or handleSetFromLocal
// because they use the term 'global' in an ES5, pre-block-scoping sense.
Scope hoistScope = scope.getClosestHoistScope();
// Consider a set to be 'global' if it is in the hoist scope in which the name is defined.
// For example, a global name set in a module scope is a 'local' set, but a module-level
// name set in a module scope is a 'global' set.
if (hoistScope.isGlobal()
|| (root != globalRoot && hoistScope.getRootNode() == curModuleRoot)) {
handleSetFromGlobal(module, scope, n, parent, name, type, nameMetadata);
} else {
handleSetFromLocal(module, scope, n, parent, name, nameMetadata);
}
} else {
handleGet(module, scope, n, parent, name, nameMetadata);
}
}
/** Declares all subnamespaces from `goog.provide('some.long.namespace')` globally. */
private void createNamesFromProvide(String namespace) {
Name name;
int dot = 0;
while (dot >= 0) {
dot = namespace.indexOf('.', dot + 1);
String subNamespace = dot < 0 ? namespace : namespace.substring(0, dot);
checkState(!subNamespace.isEmpty());
name = getOrCreateName(subNamespace, null);
name.isProvided = true;
}
Name newName = getOrCreateName(namespace, null);
newName.isProvided = true;
}
/**
* Whether the given name root represents a global or module-level name
*
*
This method will return false for functions and blocks and true for module bodies and the
* {@code globalRoot}. The one exception is if the function or block is from a goog.loadModule
* argument, as those functions/blocks are treated as module roots.
*/
private boolean isTopLevelScopeRoot(Node root) {
if (root == null) {
return false;
} else if (root == globalRoot) {
return true;
} else if (root == curModuleRoot) {
return true;
}
// Given
// goog.loadModule(function(exports) {
// pretend that assignments to `exports` or `exports.x = ...` are scoped to the function body,
// although `exports` is really in the enclosing function parameter scope.
return curModuleRoot != null && curModuleRoot.isBlock() && root == curModuleRoot.getParent();
}
/**
* Gets the fully qualified name corresponding to an object pattern key, as long as it is not in
* a nested pattern and is destructuring an qualified name.
*
* @param stringKey A child of an OBJECT_PATTERN node
* @return The global name, or null if {@code n} doesn't correspond to the key of an object
* literal that can be named
*/
String getNameForObjectPatternKey(Node stringKey) {
Node parent = stringKey.getParent();
checkState(parent.isObjectPattern());
Node patternParent = parent.getParent();
if (patternParent.isAssign() || patternParent.isDestructuringLhs()) {
// this is a top-level string key. we find the name.
Node rhs = patternParent.getSecondChild();
if (rhs == null || !rhs.isQualifiedName()) {
// The rhs is null for patterns in parameter lists, enhanced for loops, and catch exprs
return null;
}
return rhs.getQualifiedName() + "." + stringKey.getString();
} else {
// skip this step for nested patterns for now
return null;
}
}
/**
* Gets the type of a value or simple expression.
*
* @param n An r-value in an assignment or variable declaration (not null)
*/
NameType getValueType(Node n) {
switch (n.getToken()) {
case CLASS:
return NameType.CLASS;
case OBJECTLIT:
return NameType.OBJECTLIT;
case FUNCTION:
return NameType.FUNCTION;
case OR:
// Recurse on the second value. If the first value were an object
// literal or function, then the OR would be meaningless and the
// second value would be dead code. Assume that if the second value
// is an object literal or function, then the first value will also
// evaluate to one when it doesn't evaluate to false.
return getValueType(n.getLastChild());
case HOOK:
// The same line of reasoning used for the OR case applies here.
Node second = n.getSecondChild();
NameType t = getValueType(second);
if (t != NameType.OTHER) {
return t;
}
Node third = second.getNext();
return getValueType(third);
default:
break;
}
return NameType.OTHER;
}
/**
* Updates our representation of the global namespace to reflect an assignment to a global name
* in any scope where variables are hoisted to the global scope (i.e. the global scope in an ES5
* sense).
*
* @param module the current module
* @param scope the current scope
* @param n The node currently being visited
* @param parent {@code n}'s parent
* @param name The global name (e.g. "a" or "a.b.c.d")
* @param type The type of the value that the name is being assigned
*/
void handleSetFromGlobal(
JSModule module,
Scope scope,
Node n,
Node parent,
String name,
NameType type,
ModuleMetadata metadata) {
if (maybeHandlePrototypePrefix(module, scope, n, parent, name, metadata)) {
return;
}
Name nameObj = getOrCreateName(name, metadata);
if (!nameObj.isGetOrSetDefinition()) {
// Don't change the type of a getter or setter. This is because given:
// var a = {set b(item) {}}; a.b = class {};
// `a.b = class {};` does not change the runtime value of a.b, and we do not want to change
// the 'type' of a.b to Type.CLASS.
// TODO(lharker): for non-setter cases, do we really want to just treat the last set of
// a name as canonical? e.g. what if a name is first set to a class, then an object literal?
nameObj.type = type;
}
if (n.getBooleanProp(Node.MODULE_EXPORT)) {
nameObj.isModuleProp = true;
}
if (isNestedAssign(parent)) {
// This assignment is both a set and a get that creates an alias.
Ref.Type refType = Ref.Type.SET_FROM_GLOBAL;
addOrConfirmTwinRefs(nameObj, n, refType, module, scope);
} else {
addOrConfirmRef(nameObj, n, Ref.Type.SET_FROM_GLOBAL, module, scope);
if (isTypeDeclaration(n)) {
// Names with a @constructor or @enum annotation are always collapsed
nameObj.setDeclaredType();
}
}
}
/**
* If Refs already exist for the given Node confirm they match what we would create. Otherwise,
* create them.
*
* @param nameObj
* @param node
* @param setRefType
* @param module
* @param scope
*/
private void addOrConfirmTwinRefs(
Name nameObj, Node node, Ref.Type setRefType, JSModule module, Scope scope) {
ImmutableList existingRefs = nameObj.getRefsForNode(node);
if (existingRefs.isEmpty()) {
nameObj.addTwinRefs(module, scope, node, setRefType, currentPreOrderIndex);
currentPreOrderIndex += 2; // addTwinRefs uses 2 index values
} else {
checkState(existingRefs.size() == 2, "unexpected existing refs: %s", existingRefs);
Ref setRef = existingRefs.get(0);
// module and scope are dependent on Node, so not much point in checking them
// the type of the getRef is set within the Name class, so no need to check that either.
checkState(setRef.type == setRefType, "unexpected existing set Ref type: %s", setRef.type);
}
}
/**
* Determines whether a set operation is a constructor or enumeration or interface declaration.
* The set operation may either be an assignment to a name, a variable declaration, or an object
* literal key mapping.
*
* @param n The node that represents the name being set
* @return Whether the set operation is either a constructor or enum declaration
*/
private boolean isTypeDeclaration(Node n) {
Node valueNode = NodeUtil.getRValueOfLValue(n);
if (valueNode == null) {
return false;
} else if (valueNode.isClass()) {
// Always treat classes as having a declared type. (Transpiled classes are annotated
// @constructor)
return true;
}
JSDocInfo info = NodeUtil.getBestJSDocInfo(n);
// Heed the annotations only if they're sensibly used.
return info != null
&& ((info.isConstructor() && valueNode.isFunction())
|| (info.isInterface() && valueNode.isFunction())
|| (info.hasEnumParameterType() && valueNode.isObjectLit()));
}
/**
* Updates our representation of the global namespace to reflect an assignment to a global name
* in a local scope.
*
* @param module The current module
* @param scope The current scope
* @param n The node currently being visited
* @param parent {@code n}'s parent
* @param name The global name (e.g. "a" or "a.b.c.d")
*/
void handleSetFromLocal(
JSModule module, Scope scope, Node n, Node parent, String name, ModuleMetadata metadata) {
if (maybeHandlePrototypePrefix(module, scope, n, parent, name, metadata)) {
return;
}
Name nameObj = getOrCreateName(name, metadata);
if (n.getBooleanProp(Node.MODULE_EXPORT)) {
nameObj.isModuleProp = true;
}
if (isNestedAssign(parent)) {
// This assignment is both a set and a get that creates an alias.
addOrConfirmTwinRefs(nameObj, n, Ref.Type.SET_FROM_LOCAL, module, scope);
} else {
addOrConfirmRef(nameObj, n, Ref.Type.SET_FROM_LOCAL, module, scope);
}
}
/**
* Updates our representation of the global namespace to reflect a read of a global name.
*
* @param module The current module
* @param scope The current scope
* @param n The node currently being visited
* @param parent {@code n}'s parent
* @param name The global name (e.g. "a" or "a.b.c.d")
*/
void handleGet(
JSModule module, Scope scope, Node n, Node parent, String name, ModuleMetadata metadata) {
if (maybeHandlePrototypePrefix(module, scope, n, parent, name, metadata)) {
return;
}
Ref.Type type;
switch (parent.getToken()) {
case EXPR_RESULT:
case IF:
case INSTANCEOF:
case TYPEOF:
case VOID:
case NOT:
case BITNOT:
case POS:
case NEG:
type = Ref.Type.DIRECT_GET;
break;
case CALL:
if (n == parent.getFirstChild()) {
// It is a call target
type = Ref.Type.CALL_GET;
} else if (isClassDefiningCall(parent)) {
type = Ref.Type.DIRECT_GET;
} else {
type = Ref.Type.ALIASING_GET;
}
break;
case NEW:
type = n == parent.getFirstChild() ? Ref.Type.DIRECT_GET : Ref.Type.ALIASING_GET;
break;
case OR:
case AND:
case COALESCE:
// This node is x or y in (x||y), (x&&y), or (x??y). We only know that an
// alias is not getting created for this name if the result is used
// in a boolean context or assigned to the same name
// (e.g. var a = a || {}).
type = determineGetTypeForHookOrBooleanExpr(module, scope, parent, name);
break;
case HOOK:
if (n != parent.getFirstChild()) {
// This node is y or z in (x?y:z). We only know that an alias is
// not getting created for this name if the result is assigned to
// the same name (e.g. var a = a ? a : {}).
type = determineGetTypeForHookOrBooleanExpr(module, scope, parent, name);
} else {
type = Ref.Type.DIRECT_GET;
}
break;
case DELPROP:
type = Ref.Type.DELETE_PROP;
break;
case CLASS:
// This node is the superclass in an extends clause.
type = Ref.Type.SUBCLASSING_GET;
break;
case DESTRUCTURING_LHS:
case ASSIGN:
Node lhs = n.getPrevious();
if (lhs.isCast()) {
// Case: `/** @type {!Foo} */ (x) = ...`;
lhs = lhs.getOnlyChild();
}
switch (lhs.getToken()) {
case NAME:
case GETPROP:
case GETELEM:
// The rhs of an assign or a name declaration is escaped if it's assigned to a name
// directly ...
case ARRAY_PATTERN:
case OBJECT_PATTERN:
// ... or referenced through numeric/object keys.
type = Ref.Type.ALIASING_GET;
break;
default:
throw new IllegalStateException(
"Unexpected previous sibling of " + n.getToken() + ": " + n.getPrevious());
}
break;
case OBJECT_PATTERN: // Handle STRING_KEYS in object patterns.
case ITER_SPREAD:
case OBJECT_SPREAD:
default:
type = Ref.Type.ALIASING_GET;
break;
}
handleGet(module, scope, n, parent, name, type, metadata);
}
/**
* Updates our representation of the global namespace to reflect a read of a global name.
*
* @param module The current module
* @param scope The current scope
* @param n The node currently being visited
* @param parent {@code n}'s parent
* @param name The global name (e.g. "a" or "a.b.c.d")
* @param type The reference type
*/
void handleGet(
JSModule module,
Scope scope,
Node n,
Node parent,
String name,
Ref.Type type,
ModuleMetadata metadata) {
Name nameObj = getOrCreateName(name, metadata);
// No need to look up additional ancestors, since they won't be used.
addOrConfirmRef(nameObj, n, type, module, scope);
}
/**
* If there is already a Ref for the given name & node, confirm it matches what we would create.
* Otherwise add a new one.
*/
private void addOrConfirmRef(
Name nameObj, Node node, Ref.Type refType, JSModule module, Scope scope) {
ImmutableList existingRefs = nameObj.getRefsForNode(node);
if (existingRefs.isEmpty()) {
nameObj.addSingleRef(module, scope, node, refType, currentPreOrderIndex++);
} else {
checkState(existingRefs.size() == 1, "unexpected twin refs: %s", existingRefs);
// module and scope are dependent on Node, so not much point in checking them
Ref.Type existingRefType = existingRefs.get(0).type;
checkState(
existingRefType == refType,
"existing ref type: %s expected: %s",
existingRefType,
refType);
}
}
private boolean isClassDefiningCall(Node callNode) {
CodingConvention convention = compiler.getCodingConvention();
// Look for goog.inherits, goog.mixin
SubclassRelationship classes = convention.getClassesDefinedByCall(callNode);
if (classes != null) {
return true;
}
// Look for calls to goog.addSingletonGetter calls.
String className = convention.getSingletonGetterClassName(callNode);
return className != null;
}
/** Detect calls of the form a.b.hasOwnProperty(c); that prevent property collapsing on a.b */
private boolean isObjectHasOwnPropertyCall(Node callNode) {
checkArgument(callNode.isCall(), callNode);
if (!callNode.hasTwoChildren()) {
return false;
}
Node fn = callNode.getFirstChild();
if (!fn.isGetProp()) {
return false;
}
Node callee = fn.getFirstChild();
Node method = fn.getSecondChild();
return method.isString()
&& "hasOwnProperty".equals(method.getString())
&& callee.isQualifiedName();
}
/**
* Determines whether the result of a hook (x?y:z) or boolean expression (x||y) or (x&&y) is
* assigned to a specific global name.
*
* @param module The current module
* @param scope The current scope
* @param parent The parent of the current node in the traversal. This node should already be
* known to be a HOOK, AND, or OR node.
* @param name A name that is already known to be global in the current scope (e.g. "a" or
* "a.b.c.d")
* @return The expression's get type, either {@link Ref.Type#DIRECT_GET} or {@link
* Ref.Type#ALIASING_GET}
*/
Ref.Type determineGetTypeForHookOrBooleanExpr(
JSModule module, Scope scope, Node parent, String name) {
Node prev = parent;
for (Node anc : parent.getAncestors()) {
switch (anc.getToken()) {
case INSTANCEOF:
case EXPR_RESULT:
case VAR:
case LET:
case CONST:
case IF:
case WHILE:
case FOR:
case FOR_IN:
case TYPEOF:
case VOID:
case NOT:
case BITNOT:
case POS:
case NEG:
return Ref.Type.DIRECT_GET;
case HOOK:
if (anc.getFirstChild() == prev) {
return Ref.Type.DIRECT_GET;
}
break;
case ASSIGN:
if (!anc.getFirstChild().matchesQualifiedName(name)) {
return Ref.Type.ALIASING_GET;
}
break;
case NAME: // a variable declaration
if (!name.equals(anc.getString())) {
return Ref.Type.ALIASING_GET;
}
break;
case CALL:
if (anc.getFirstChild() != prev) {
return Ref.Type.ALIASING_GET;
}
break;
case DELPROP:
return Ref.Type.DELETE_PROP;
default:
break;
}
prev = anc;
}
return Ref.Type.ALIASING_GET;
}
/**
* Updates our representation of the global namespace to reflect a read of a global name's
* longest prefix before the "prototype" property if the name includes the "prototype" property.
* Does nothing otherwise.
*
* @param module The current module
* @param scope The current scope
* @param n The node currently being visited
* @param parent {@code n}'s parent
* @param name The global name (e.g. "a" or "a.b.c.d")
* @return Whether the name was handled
*/
boolean maybeHandlePrototypePrefix(
JSModule module, Scope scope, Node n, Node parent, String name, ModuleMetadata metadata) {
// We use a string-based approach instead of inspecting the parse tree
// to avoid complexities with object literals, possibly nested, beneath
// assignments.
int numLevelsToRemove;
String prefix;
if (name.endsWith(".prototype")) {
numLevelsToRemove = 1;
prefix = name.substring(0, name.length() - 10);
} else {
int i = name.indexOf(".prototype.");
if (i == -1) {
return false;
}
prefix = name.substring(0, i);
numLevelsToRemove = 2;
i = name.indexOf('.', i + 11);
while (i >= 0) {
numLevelsToRemove++;
i = name.indexOf('.', i + 1);
}
}
if (parent != null && NodeUtil.mayBeObjectLitKey(n)) {
// Object literal keys have no prefix that's referenced directly per
// key, so we're done.
return true;
}
for (int i = 0; i < numLevelsToRemove; i++) {
parent = n;
n = n.getFirstChild();
}
handleGet(module, scope, n, parent, prefix, Ref.Type.PROTOTYPE_GET, metadata);
return true;
}
/**
* Determines whether an assignment is nested (i.e. whether its return value is used).
*
* @param parent The parent of the current traversal node (not null)
* @return Whether it appears that the return value of the assignment is used
*/
boolean isNestedAssign(Node parent) {
return parent.isAssign() && !parent.getParent().isExprResult();
}
/**
* Gets a {@link Name} instance for a global name. Creates it if necessary, as well as instances
* for any of its prefixes that are not yet defined.
*
* @param name A global name (e.g. "a", "a.b.c.d")
* @return The {@link Name} instance for {@code name}
*/
Name getOrCreateName(String name, ModuleMetadata metadata) {
Name node = metadata == null ? nameMap.get(name) : nameMapByModule.get(metadata, name);
if (node == null) {
int i = name.lastIndexOf('.');
if (i >= 0) {
String parentName = name.substring(0, i);
Name parent = getOrCreateName(parentName, metadata);
node = parent.addProperty(name.substring(i + 1), sourceKind);
if (metadata == null) {
nameMap.put(name, node);
} else {
nameMapByModule.put(metadata, name, node);
}
} else {
node = new Name(name, null, sourceKind);
if (metadata == null) {
globalNames.add(node);
nameMap.put(name, node);
} else {
nameMapByModule.put(metadata, name, node);
}
}
}
return node;
}
}
// -------------------------------------------------------------------------
@VisibleForTesting
Name createNameForTesting(String name) {
return new Name(name, null, SourceKind.CODE);
}
private enum NameType {
CLASS, // class C {}
OBJECTLIT, // var x = {};
FUNCTION, // function f() {}
SUBCLASSING_GET, // class C extends SuperClass {
GET_SET, // a getter, setter, or both; e.g. `obj.b` in `const obj = {set b(x) {}};`
OTHER; // anything else, including `var x = 1;`, var x = new Something();`, etc.
}
/**
* How much to inline a {@link Name}.
*
* The {@link INLINE_BUT_KEEP_DECLARATION} case is really an indicator that something 'unsafe'
* is happening in order to not break CollapseProperties as badly. Sadly {@link INLINE_COMPLETELY}
* may also be unsafe.
*/
enum Inlinability {
INLINE_COMPLETELY,
INLINE_BUT_KEEP_DECLARATION,
DO_NOT_INLINE;
boolean shouldInlineUsages() {
return this != DO_NOT_INLINE;
}
boolean shouldRemoveDeclaration() {
return this == INLINE_COMPLETELY;
}
boolean canCollapse() {
return this != DO_NOT_INLINE;
}
}
/**
* A name defined in global scope (e.g. "a" or "a.b.c.d").
*
*
Instances form a tree describing the "Closure namespaces" in the program. As the parse tree
* traversal proceeds, we'll discover that some names correspond to JavaScript objects whose
* properties we should consider collapsing.
*/
final class Name implements StaticSlot {
private final String baseName;
private final Name parent;
// The children of this name. Must be null if there are no children.
@Nullable List props;
/** The first global assignment to a name. */
private Ref declaration;
/** All references to a name. This must contain {@code declaration}. */
private final LinkedHashSet refs = new LinkedHashSet<>();
/** Keep track of which Nodes are Refs for this Name */
private final Map> refsForNodeMap = new HashMap<>();
private NameType type; // not final to handle forward references to names
private boolean declaredType = false;
private boolean isDeclared = false;
private boolean isModuleProp = false;
private boolean isProvided = false; // If this name was in any goog.provide() calls.
private boolean usedHasOwnProperty = false;
private int globalSets = 0;
private int localSets = 0;
private int localSetsWithNoCollapse = 0;
private int aliasingGets = 0;
private int totalGets = 0;
private int callGets = 0;
private int deleteProps = 0;
private int subclassingGets = 0;
private final SourceKind sourceKind;
// Will be set to the JSDocInfo associated with the first SET_FROM_GLOBAL reference added
// that has JSDocInfo.
// e.g.
// /** @type {number} */
// X.numberProp = 3;
@Nullable private JSDocInfo firstDeclarationJSDocInfo = null;
// Will be set to the JSDocInfo associated with the first get reference that is a statement
// by itself.
// e.g.
// /** @type {number} */
// X.numberProp;
@Nullable private JSDocInfo firstQnameDeclarationWithoutAssignmentJsDocInfo = null;
private Name(String name, Name parent, SourceKind sourceKind) {
this.baseName = name;
this.parent = parent;
this.type = NameType.OTHER;
this.sourceKind = sourceKind;
}
Name addProperty(String name, SourceKind sourceKind) {
if (props == null) {
props = new ArrayList<>();
}
Name node = new Name(name, this, sourceKind);
props.add(node);
return node;
}
String getBaseName() {
return baseName;
}
boolean inExterns() {
return this.sourceKind == SourceKind.EXTERN;
}
SourceKind getSourceKind() {
return this.sourceKind;
}
int subclassingGetCount() {
return this.subclassingGets;
}
@Override
public String getName() {
return getFullName();
}
String getFullName() {
return parent == null ? baseName : parent.getFullName() + '.' + baseName;
}
@Nullable
@Override
public Ref getDeclaration() {
return declaration;
}
boolean isFunction() {
return this.type == NameType.FUNCTION;
}
boolean isClass() {
return this.type == NameType.CLASS;
}
boolean isObjectLiteral() {
return this.type == NameType.OBJECTLIT;
}
int getAliasingGets() {
return aliasingGets;
}
int getSubclassingGets() {
return subclassingGets;
}
int getLocalSets() {
return localSets;
}
int getGlobalSets() {
return globalSets;
}
int getCallGets() {
return callGets;
}
int getTotalGets() {
return totalGets;
}
int getDeleteProps() {
return deleteProps;
}
Name getParent() {
return parent;
}
@Override
public StaticScope getScope() {
throw new UnsupportedOperationException();
}
/**
* Add a pair of Refs for the same Node.
*
* This covers cases like `var a = b = 0`. The 'b' node needs a ALIASING_GET reference and a
* SET_FROM_GLOBAL or SET_FROM_LOCAL reference.
*
* @param module
* @param scope
* @param node
* @param setType either SET_FROM_LOCAL or SET_FROM_GLOBAL
* @param setRefPreOrderIndex used for setter Ref, getter ref will be this value + 1
*/
private void addTwinRefs(
JSModule module, Scope scope, Node node, Ref.Type setType, int setRefPreOrderIndex) {
checkArgument(
setType == Ref.Type.SET_FROM_GLOBAL || setType == Ref.Type.SET_FROM_LOCAL, setType);
Ref setRef = createNewRef(module, scope, node, setType, setRefPreOrderIndex);
Ref getRef =
createNewRef(module, scope, node, Ref.Type.ALIASING_GET, setRefPreOrderIndex + 1);
setRef.twin = getRef;
getRef.twin = setRef;
refsForNodeMap.put(node, ImmutableList.of(setRef, getRef));
refs.add(setRef);
updateStateForAddedRef(setRef);
refs.add(getRef);
updateStateForAddedRef(getRef);
}
private void addSingleRef(
JSModule module, Scope scope, Node node, Ref.Type type, int preOrderIndex) {
checkNoExistingRefsForNode(node);
Ref ref = createNewRef(module, scope, node, type, preOrderIndex);
refs.add(ref);
refsForNodeMap.put(node, ImmutableList.of(ref));
updateStateForAddedRef(ref);
}
private void checkNoExistingRefsForNode(Node node) {
ImmutableList refsForNode = refsForNodeMap.get(node);
checkState(refsForNode == null, "Refs already exist for node: %s", refsForNode);
}
private Ref createNewRef(
JSModule module, Scope scope, Node node, Ref.Type type, int preOrderIndex) {
return new Ref(
module, // null if the compilation isn't using JSModules
checkNotNull(scope),
checkNotNull(node), // may be null later, but not on creation
this,
type,
preOrderIndex);
}
Ref addSingleRefForTesting(Ref.Type type, int preOrderIndex) {
Ref ref =
new Ref(
/* module= */ null, /* scope= */ null, /* node = */ null, this, type, preOrderIndex);
refs.add(ref);
// node is Null for testing in this case, so nothing to add to refsForNodeMap
updateStateForAddedRef(ref);
return ref;
}
/**
* Add an ALIASING_GET Ref for the given Node using the same Ref properties as the declaration
* Ref, which must exist.
*
* Only for use by CollapseProperties.
*
* @param newRefNode newly added AST node that refers to this Name and appears in the same
* module and scope as the Ref that declares this Name
*/
void addAliasingGetClonedFromDeclaration(Node newRefNode) {
// TODO(bradfordcsmith): It would be good to add checks that the scope and module are correct.
Ref declRef = checkNotNull(declaration);
addSingleRef(
declRef.module, declRef.scope, newRefNode, Ref.Type.ALIASING_GET, declRef.preOrderIndex);
}
/**
* Updates counters and JSDocInfo recorded for the name to include a newly added Ref.
*
*
Must be called exactly once when a new Ref is added.
*
* @param ref a Ref that has just been added for this Name
*/
private void updateStateForAddedRef(Ref ref) {
switch (ref.type) {
case SET_FROM_GLOBAL:
if (declaration == null) {
declaration = ref;
}
if (firstDeclarationJSDocInfo == null) {
// JSDocInfo from the first SET_FROM_GLOBAL will be assumed to be canonical
// Note that this will not change if the first declaration is later removed
// by optimizations.
firstDeclarationJSDocInfo = getDocInfoForDeclaration(ref);
}
globalSets++;
break;
case SET_FROM_LOCAL:
localSets++;
JSDocInfo info = ref.getNode() == null ? null : NodeUtil.getBestJSDocInfo(ref.getNode());
if (info != null && info.isNoCollapse()) {
localSetsWithNoCollapse++;
}
break;
case PROTOTYPE_GET:
case DIRECT_GET:
Node node = ref.getNode();
if (firstQnameDeclarationWithoutAssignmentJsDocInfo == null
&& isQnameDeclarationWithoutAssignment(node)) {
// /** @type {sometype} */
// some.qname.ref;
firstQnameDeclarationWithoutAssignmentJsDocInfo = node.getJSDocInfo();
}
totalGets++;
break;
case ALIASING_GET:
aliasingGets++;
totalGets++;
break;
case CALL_GET:
callGets++;
totalGets++;
break;
case DELETE_PROP:
deleteProps++;
break;
case SUBCLASSING_GET:
subclassingGets++;
totalGets++;
break;
default:
throw new IllegalStateException();
}
}
/**
* This is the only safe way to update the Node belonging to a Ref once it is added to a Name.
*
*
This is a specialized method that exists only for use by CollapseProperties.
*
* @param ref reference to update - it must belong to this name
* @param newNode new value for the ref's node
*/
void updateRefNode(Ref ref, @Nullable Node newNode) {
checkArgument(ref.node != newNode, "redundant update to Ref node: %s", ref);
// Once a Ref's node is set to null, it shouldn't ever be set to anything else.
// TODO(bradfordcsmith): Document here what it means when we set the node to null.
// Seems to be a way to keep name.getDeclaration() returning the original declaration
// Ref even though its node is no longer in the AST.
Node oldNode = ref.getNode();
checkState(oldNode != null, "Ref's node is already null: %s", ref);
ref.node = newNode;
// If this ref was a twin, it isn't anymore, and its previous twin is now the only ref to the
// original node.
Ref twinRef = ref.getTwin();
if (twinRef != null) {
ref.twin = null;
twinRef.twin = null;
refsForNodeMap.put(oldNode, ImmutableList.of(twinRef));
} else {
refsForNodeMap.remove(oldNode); // this ref was the only reference on the node
}
if (newNode != null) {
ImmutableList existingRefsForNewNode = refsForNodeMap.get(newNode);
checkArgument(
existingRefsForNewNode == null, "refs already exist: %s", existingRefsForNewNode);
refsForNodeMap.put(newNode, ImmutableList.of(ref));
}
}
/**
* Remove a Ref and its twin at the same time.
*
* If you intend to remove both, it is more efficient and less error prone to use this method
* instead of removing them one at a time.
*
* @param ref A Ref that has a twin.
*/
void removeTwinRefs(Ref ref) {
checkArgument(
ref.name == this, "removeTwinRefs(%s): node does not belong to this name: %s", ref, this);
checkState(refs.contains(ref), "removeRef(%s): unknown ref", ref);
Ref twinRef = ref.getTwin();
checkArgument(twinRef != null, ref);
removeTwinRefsFromNodeMap(ref);
removeRefAndUpdateState(ref);
removeRefAndUpdateState(twinRef);
}
/**
* Removes the given Ref, which must belong to this Name.
*
*
NOTE: if ref has a twin, they will no longer be twins after this method finishes. Use
* removeTwinRefs() to remove a pair of twins at the same time.
*
* @param ref
*/
void removeRef(Ref ref) {
checkState(
ref.name == this, "removeRef(%s): node does not belong to this name: %s", ref, this);
checkState(refs.contains(ref), "removeRef(%s): unknown ref", ref);
Node refNode = ref.getNode();
if (refNode != null) {
removeSingleRefFromNodeMap(ref);
}
removeRefAndUpdateState(ref);
}
/**
* Update counts, declaration, and JSDoc to reflect removal of the given Ref.
*
* @param ref
*/
private void removeRefAndUpdateState(Ref ref) {
refs.remove(ref);
if (ref == declaration) {
declaration = null;
for (Ref maybeNewDecl : refs) {
if (maybeNewDecl.type == Ref.Type.SET_FROM_GLOBAL) {
declaration = maybeNewDecl;
break;
}
}
}
JSDocInfo info;
switch (ref.type) {
case SET_FROM_GLOBAL:
globalSets--;
break;
case SET_FROM_LOCAL:
localSets--;
info = ref.getNode() == null ? null : NodeUtil.getBestJSDocInfo(ref.getNode());
if (info != null && info.isNoCollapse()) {
localSetsWithNoCollapse--;
}
break;
case PROTOTYPE_GET:
case DIRECT_GET:
totalGets--;
break;
case ALIASING_GET:
aliasingGets--;
totalGets--;
break;
case CALL_GET:
callGets--;
totalGets--;
break;
case DELETE_PROP:
deleteProps--;
break;
case SUBCLASSING_GET:
subclassingGets--;
totalGets--;
break;
// Leaving off default: allows compile-time enforcement that all values are covered
}
}
private void removeSingleRefFromNodeMap(Ref ref) {
Node refNode = checkNotNull(ref.getNode(), ref);
if (ref.getTwin() != null) {
removeTwinRefsFromNodeMap(ref);
Ref twinRef = ref.getTwin();
// break the twin relationship
ref.twin = null;
twinRef.twin = null;
// put twin back alone, since we're not really removing it
refsForNodeMap.put(refNode, ImmutableList.of(twinRef));
} else {
ImmutableList refsForNode = refsForNodeMap.get(refNode);
checkState(
refsForNode.size() == 1 && refsForNode.get(0) == ref,
"Unexpected Refs for Node: %s: when removing Ref: %s",
refsForNode,
ref);
refsForNodeMap.remove(refNode);
}
}
private void removeTwinRefsFromNodeMap(Ref ref) {
Ref twinRef = checkNotNull(ref.getTwin(), ref);
Node refNode = checkNotNull(ref.getNode(), ref);
ImmutableList refsForNode = refsForNodeMap.get(refNode);
checkState(
refsForNode.size() == 2,
"unexpected Refs for Node: %s, when removing: %s",
refsForNode,
ref);
checkState(
refsForNode.contains(ref),
"Refs for Node: %s does not contain Ref to remove: %s",
refsForNode,
ref);
checkState(
refsForNode.contains(twinRef),
"Refs for Node: %s does not contain expected twin: %s",
refsForNode,
twinRef);
refsForNodeMap.remove(refNode);
}
Collection getRefs() {
return refs == null ? ImmutableList.of() : Collections.unmodifiableCollection(refs);
}
/**
* Get the Refs for this name that belong to the given node.
*
* Returns an empty list if there are no Refs, or a list with only one Ref, or a list with
* exactly 2 refs that are twins of each other.
*/
@VisibleForTesting
ImmutableList getRefsForNode(Node node) {
ImmutableList refsForNode = refsForNodeMap.get(checkNotNull(node));
return (refsForNode == null) ? ImmutableList.of() : refsForNode;
}
Ref getFirstRef() {
checkState(!refs.isEmpty(), "no first Ref to get");
return Iterables.get(refs, 0);
}
boolean canEliminate() {
if (!canCollapseUnannotatedChildNames() || totalGets > 0) {
return false;
}
if (props != null) {
for (Name n : props) {
if (!n.canCollapse()) {
return false;
}
}
}
return true;
}
boolean isSimpleStubDeclaration() {
if (getRefs().size() == 1) {
Ref ref = Iterables.get(refs, 0);
if (ref.node.getParent().isExprResult()) {
return true;
}
}
return false;
}
boolean isCollapsingExplicitlyDenied() {
JSDocInfo docInfo = getJSDocInfo();
return docInfo != null && docInfo.isNoCollapse();
}
/**
* Returns whether to treat this alias as completely inlinable or to keep the aliasing
* assignment
*
* This method used to only return true/false, but now returns an enum in order to track more
* information about "unsafely" inlinable names.
*
*
CollapseProperties will flatten `@constructor` properties even if they are potentially
* accessed by a reference other than their fully qualified name, which breaks those other refs.
* To avoid breakages AggressiveInlineAliases must unsafely inline constructor properties that
* alias another global name. Existing code depends on this behavior, and it's not easily
* determinable where these dependencies are.
*
*
However, AggressiveInlineAliases must not also remove the initializtion of an alias if it
* is not safely inlinable. (i.e. if Inlinability#shouldRemoveDeclaration()). It's possible that
* a third name aliases the alias - we might later inline the third name (as an alias of the
* original alias) and don't want to set the third name to null.
*/
Inlinability calculateInlinability() {
// Only simple aliases with direct usage are inlinable.
if (inExterns() || globalSets != 1 || localSets != 0) {
return Inlinability.DO_NOT_INLINE;
}
// TODO(lharker): consider separating canCollapseOrInline() into this method, since it
// duplicates some logic here
Inlinability collapsibility = canCollapseOrInline();
if (!collapsibility.shouldInlineUsages()) {
// if you can't even inline the usages, do nothing.
return Inlinability.DO_NOT_INLINE;
}
// Only allow inlining of simple references.
for (Ref ref : getRefs()) {
switch (ref.type) {
case SET_FROM_GLOBAL:
// Expect one global set
continue;
case SET_FROM_LOCAL:
throw new IllegalStateException();
case ALIASING_GET:
case DIRECT_GET:
case PROTOTYPE_GET:
case CALL_GET:
case SUBCLASSING_GET:
continue;
case DELETE_PROP:
return Inlinability.DO_NOT_INLINE;
default:
throw new IllegalStateException();
}
}
return collapsibility;
}
boolean canCollapse() {
return canCollapseOrInline().canCollapse();
}
/**
* Determines whether it's safe to collapse properties on an objects
*
*
For legacy reasons, both CollapseProperties and AggressiveInlineAliases share the same
* logic when deciding whether to inline properties or to collapse them.
*
*
The main reasons we cannot inline/collapse properties of a name name are:
*
*
* a) it is set multiple times or set once in a local scope,
* b) one or more of the above conditions in canCollapseOrInlineChildNames
* applies to the namespace it's on,
* c) it's annotated at-nocollapse
* d) it's in the externs,
* e) or it's a known getter or setter, not a regular property
* f) it's an ES6 class static method that references `super` or the internal class name
*
*
* We ignore conditions (a) and (b) on at-constructor and at-enum names in
* CollapseProperties.
*
*
In AggressiveInlineAliases we want to do some partial backoff if (a) and (b) are false for
* at-constructor or at-enum names, which is why we return an enum value instead of a boolean.
*/
private Inlinability canCollapseOrInline() {
if (inExterns()) {
// condition (d)
return Inlinability.DO_NOT_INLINE;
}
if (isGetOrSetDefinition()) {
// condition (e)
return Inlinability.DO_NOT_INLINE;
}
if (isCollapsingExplicitlyDenied()) {
// condition (c)
return Inlinability.DO_NOT_INLINE;
}
if (referencesSuperOrInnerClassName()) {
// condition (f)
return Inlinability.DO_NOT_INLINE;
}
if (getDeclaration() != null) {
Node declaration = getDeclaration().getNode();
if (declaration.getParent().isObjectLit()) {
if (declarationHasFollowingObjectSpreadSibling(declaration)) {
// Case: `var x = {a: 0, ...b, c: 2}` where declaration is `a` but not `c`.
// Following spreads may overwrite the declaration.
return Inlinability.DO_NOT_INLINE;
}
Node grandparent = declaration.getGrandparent();
if (grandparent.isOr() || grandparent.isHook()) {
// Case: `var x = y || {a: b}` or `var x = cond ? y : {a: b}`.
return Inlinability.DO_NOT_INLINE;
}
}
}
// condition (a)
boolean isUnchangedThroughFullName =
(globalSets > 0 || localSets > 0) && localSetsWithNoCollapse == 0 && deleteProps == 0;
// additional information about condition (b)
Inlinability parentInlinability =
parent == null ? Inlinability.INLINE_COMPLETELY : parent.canCollapseOrInlineChildNames();
// if condition (a) or condition (b) is not true, but this is a declared name, we may need
// to allow inlining usages of a variable but keep the declaration.
switch (parentInlinability) {
case INLINE_COMPLETELY:
if (isUnchangedThroughFullName) {
return Inlinability.INLINE_COMPLETELY;
}
// maybe inline usages of this name, but only if a declared type. non-declared-types just
// back off and don't inline at all
return declaredType
? Inlinability.INLINE_BUT_KEEP_DECLARATION
: Inlinability.DO_NOT_INLINE;
case INLINE_BUT_KEEP_DECLARATION:
// this is definitely not safe to completely inline/collapse of its parent
// if it's a declared type, we should still partially inline it and completely collapse it
// if not a declared type we should partially inline it iff the other conditions hold
if (declaredType) {
return Inlinability.INLINE_BUT_KEEP_DECLARATION;
}
// Not a declared type. We may still 'partially' inline it because it must be a property
// on an @enum or @constructor, but only if it actually matches conditions (a) and (b)
return isUnchangedThroughFullName
? Inlinability.INLINE_BUT_KEEP_DECLARATION
: Inlinability.DO_NOT_INLINE;
case DO_NOT_INLINE:
// If the parent is unsafely to collapse/inline, we will still inline it if it's on
// a declaredType (i.e. @constructor or @enum), but we propagate the information that
// the parent is unsafe. If this is not a declared type, return DO_NOT_INLINE.
return declaredType
? Inlinability.INLINE_BUT_KEEP_DECLARATION
: Inlinability.DO_NOT_INLINE;
}
throw new IllegalStateException("unknown enum value " + parentInlinability);
}
/**
* Examines ES6 class members for some syntax that blocks collapsing
*
*
Specifically, this looks for super references and references to inner class names. These
* are unique to ES6 static class members so we don't need more general handling.
*
*
TODO(b/122665204): also return false on `super` in an object lit method
*/
boolean referencesSuperOrInnerClassName() {
Ref ref = this.getDeclaration();
if (ref == null) {
return false;
}
Node member = ref.getNode();
if (member == null || !(member.isStaticMember() && member.getParent().isClassMembers())) {
return false;
}
if (NodeUtil.referencesSuper(NodeUtil.getFunctionBody(member.getFirstChild()))) {
return true;
}
Node classNode = member.getGrandparent();
if (NodeUtil.isClassDeclaration(classNode)) {
return false; // e.g. class C {}
}
Node innerNameNode = classNode.getFirstChild();
return !innerNameNode.isEmpty() // e.g. const C = class {};
&& NodeUtil.isNameReferenced(member, innerNameNode.getString());
}
private boolean isSetInLoop() {
Ref ref = this.getDeclaration();
if (ref != null) {
Node n = ref.getNode();
if (n != null) {
return NodeUtil.isWithinLoop(n);
}
}
return false;
}
boolean isGetOrSetDefinition() {
return this.type == NameType.GET_SET;
}
boolean canCollapseUnannotatedChildNames() {
return canCollapseOrInlineChildNames().canCollapse();
}
/**
* Returns whether to assume that child properties of this name are collapsible/inlinable
*
*
For legacy reasons, both CollapseProperties and AggressiveInlineAliases share the same
* logic when deciding whether to inline properties or to collapse them.
*
*
The main reasons we cannot inline/collapse properties of a name name are:
*
*
* a) it is set multiple times
* b) its properties might not be referred to by their full qname but on a different object
* c) one or more of the above conditions applies to a parent name
* d) it's annotated @nocollapse
* e) it's in the externs.
* f) it's assigned a value that supports being aliased (e.g. ctors, so their static
* properties can be accessed via `this`)
*
*
* However, in some cases for properties of `@constructor` or `@enum` names, we ignore some
* of these conditions in order to more aggressively collapse `@constructor`s used in
* goog.provide namespace chains.
*/
private Inlinability canCollapseOrInlineChildNames() {
if (type == NameType.OTHER
|| isGetOrSetDefinition()
|| globalSets != 1
|| localSets != 0
|| deleteProps != 0) {
// condition (a) and (b)
return Inlinability.DO_NOT_INLINE;
}
// Don't try to collapse if the one global set is a twin reference.
// We could theoretically handle this case in CollapseProperties, but
// it's probably not worth the effort.
checkNotNull(declaration);
if (declaration.getTwin() != null) {
return Inlinability.DO_NOT_INLINE;
}
if (isCollapsingExplicitlyDenied()) {
// condition (d)
return Inlinability.DO_NOT_INLINE;
}
if (isSetInLoop()) {
// condition (a)
return Inlinability.DO_NOT_INLINE;
}
if (usedHasOwnProperty) {
// condition (b)
return Inlinability.DO_NOT_INLINE;
}
if (valueImplicitlySupportsAliasing()) {
// condition (f)
return Inlinability.DO_NOT_INLINE;
}
// If this is a key of an aliased object literal, then it will be aliased
// later. So we won't be able to collapse its properties.
// condition (b)
if (parent != null && parent.shouldKeepKeys()) {
return declaredType ? Inlinability.INLINE_BUT_KEEP_DECLARATION : Inlinability.DO_NOT_INLINE;
}
// If this is aliased, then its properties can't be collapsed either. but we may do so anyway
// if it's a declared type.
// condition (b)
if (aliasingGets > 0) {
return declaredType ? Inlinability.INLINE_BUT_KEEP_DECLARATION : Inlinability.DO_NOT_INLINE;
}
if (parent == null) {
// this is completely safe to inline! yay
return Inlinability.INLINE_COMPLETELY;
}
// Cases are:
// - parent is safe to completely inline. then same for this name
// - parent is unsafe but should still be inlined. then same for this name
// - parent is unsafe, should not be inlined at all. then return either DO_NOT_INLINE,
// or maybe unsafely inline if this is a ctor property
Inlinability parentInlinability = parent.canCollapseOrInlineChildNames();
if (parentInlinability == Inlinability.DO_NOT_INLINE) {
// the parent name is used in a way making this unsafe to inline, but we might want to
// inline usages of this name
return declaredType ? Inlinability.INLINE_BUT_KEEP_DECLARATION : Inlinability.DO_NOT_INLINE;
}
return parentInlinability;
}
private boolean valueImplicitlySupportsAliasing() {
if (!GlobalNamespace.this.enableImplicityAliasedValues) {
return false;
}
switch (type) {
case CLASS:
// Properties on classes may be referenced via `this` in static methods.
return true;
case FUNCTION:
// We want ES5 ctors/interfaces to behave consistently with ES6 because:
// - transpilation should not change behaviour
// - updating code shouldn't be hindered by behaviour changes
@Nullable JSDocInfo jsdoc = getJSDocInfo();
return jsdoc != null && jsdoc.isConstructorOrInterface();
default:
return false;
}
}
/** Whether this is an object literal that needs to keep its keys. */
boolean shouldKeepKeys() {
return type == NameType.OBJECTLIT && (aliasingGets > 0 || isCollapsingExplicitlyDenied());
}
boolean needsToBeStubbed() {
return globalSets == 0
&& localSets > 0
&& localSetsWithNoCollapse == 0
&& !isCollapsingExplicitlyDenied();
}
void setDeclaredType() {
declaredType = true;
for (Name ancestor = parent; ancestor != null; ancestor = ancestor.parent) {
ancestor.isDeclared = true;
}
}
boolean isDeclaredType() {
return declaredType;
}
boolean isConstructor() {
Node declNode = declaration.node;
Node rvalueNode = NodeUtil.getRValueOfLValue(declNode);
JSDocInfo jsdoc = NodeUtil.getBestJSDocInfo(declNode);
return rvalueNode != null
&& rvalueNode.isFunction()
&& jsdoc != null
&& jsdoc.isConstructor();
}
/**
* Determines whether this name is a prefix of at least one class or enum name. Because classes
* and enums are always collapsed, the namespace will have different properties in compiled code
* than in uncompiled code.
*
*
For example, if foo.bar.DomHelper is a class, then foo and foo.bar are considered
* namespaces.
*/
boolean isNamespaceObjectLit() {
return isDeclared && type == NameType.OBJECTLIT;
}
/** Determines whether this is a simple name (as opposed to a qualified name). */
boolean isSimpleName() {
return parent == null;
}
@Override
public String toString() {
return getFullName()
+ " ("
+ type
+ "): "
+ Joiner.on(", ")
.join(
"globalSets=" + globalSets,
"localSets=" + localSets,
"totalGets=" + totalGets,
"aliasingGets=" + aliasingGets,
"callGets=" + callGets,
"subclassingGets=" + subclassingGets);
}
@Nullable
@Override
public JSDocInfo getJSDocInfo() {
// e.g.
// /** @type {string} */ X.numProp; // could be a declaration, but...
// /** @type {number} */ X.numProp = 3; // assignment wins
return firstDeclarationJSDocInfo != null
? firstDeclarationJSDocInfo
: firstQnameDeclarationWithoutAssignmentJsDocInfo;
}
/** Tries to get the doc info for a given declaration ref. */
private JSDocInfo getDocInfoForDeclaration(Ref ref) {
if (ref.node != null) {
Node refParent = ref.node.getParent();
if (refParent == null) {
// May happen when inlineAliases removes refs from the AST.
return null;
}
switch (refParent.getToken()) {
case FUNCTION:
case ASSIGN:
case CLASS:
return refParent.getJSDocInfo();
case VAR:
case LET:
case CONST:
return ref.node == refParent.getFirstChild()
? refParent.getJSDocInfo()
: ref.node.getJSDocInfo();
case OBJECTLIT:
case CLASS_MEMBERS:
return ref.node.getJSDocInfo();
default:
break;
}
}
return null;
}
boolean isModuleExport() {
return isModuleProp;
}
}
/**
* True if the given Node is the GETPROP in a statement like `some.q.name;`
*
*
Such do-nothing statements often have JSDoc on them and are intended to declare the
* qualified name.
*
* @param node any Node, or even null
*/
private static boolean isQnameDeclarationWithoutAssignment(@Nullable Node node) {
return node != null && node.isGetProp() && node.getParent().isExprResult();
}
// -------------------------------------------------------------------------
/**
* A global name reference. Contains references to the relevant parse tree node and its ancestors
* that may be affected.
*/
static class Ref implements StaticRef {
// Note: we are more aggressive about collapsing @enum and @constructor
// declarations than implied here, see Name#canCollapse
enum Type {
/**
* Set in the scope in which a name is declared, either the global scope or a module scope:
* `a.b.c = 0;` or `goog.module('mod'); exports.Foo = class {};`
*/
SET_FROM_GLOBAL, // TODO(lharker): rename this to explain it includes modules
/** Set in a local scope: function f() { a.b.c = 0; } */
SET_FROM_LOCAL,
/** Get a name's prototype: a.b.c.prototype */
PROTOTYPE_GET,
/**
* Includes all uses that prevent a name's properties from being collapsed: var x = a.b.c
* f(a.b.c) new Foo(a.b.c)
*/
ALIASING_GET,
/**
* Includes all uses that prevent a name from being completely eliminated:
* goog.inherits(anotherName, a.b.c) new a.b.c() x instanceof a.b.c void a.b.c if (a.b.c) {}
*/
DIRECT_GET,
/** Calling a name: a.b.c(); Prevents a name from being collapsed if never set. */
CALL_GET,
/** Deletion of a property: delete a.b.c; Prevents a name from being collapsed at all. */
DELETE_PROP,
/** ES6 subclassing ref: class extends A {} */
SUBCLASSING_GET,
}
// Not final because CollapseProperties needs to update the namespace in-place.
private Node node;
final JSModule module;
final Name name;
final Type type;
/**
* The scope in which the reference is resolved. Note that for ALIASING_GETS like "var x = ns;"
* this scope may not be the correct hoist scope of the aliasing VAR.
*/
final Scope scope;
final int preOrderIndex;
/**
* Certain types of references are actually double-refs. For example, var a = b = 0; counts as
* both a "set" of b and an "alias" of b.
*
*
We create two Refs for this node, and mark them as twins of each other.
*/
private Ref twin = null;
/**
* Creates a Ref
*
*
No parameter checking is done here, because we allow nulls for several fields in Refs
* created just for testing. However, all Refs for real use must be created by methods on the
* Name class, which does do argument checking.
*/
private Ref(JSModule module, Scope scope, Node node, Name name, Type type, int index) {
this.node = node;
this.name = name;
this.module = module;
this.type = type;
this.scope = scope;
this.preOrderIndex = index;
}
@Override
public Node getNode() {
return node;
}
@Override
public StaticSourceFile getSourceFile() {
return node != null ? node.getStaticSourceFile() : null;
}
@Override
public StaticSlot getSymbol() {
return name;
}
JSModule getModule() {
return module;
}
/** Returns the corresponding read/write Ref of a name in a nested assign, or null otherwise */
Ref getTwin() {
return twin;
}
boolean isSet() {
return type == Type.SET_FROM_GLOBAL || type == Type.SET_FROM_LOCAL;
}
@Override
public String toString() {
return MoreObjects.toStringHelper(this)
.omitNullValues()
.add("name", name)
.add("type", type)
.add("node", node)
.add("preOrderIndex", preOrderIndex)
.add("isTwin", twin != null)
.add("module", module)
.add("scope", scope)
.toString();
}
}
}