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3044 lines (2688 loc) · 151 KB
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/// <reference path="utilities.ts"/>
/// <reference path="parser.ts"/>
/* @internal */
namespace ts {
export const enum ModuleInstanceState {
NonInstantiated = 0,
Instantiated = 1,
ConstEnumOnly = 2
}
interface ActiveLabel {
name: string;
breakTarget: FlowLabel;
continueTarget: FlowLabel;
referenced: boolean;
}
export function getModuleInstanceState(node: Node): ModuleInstanceState {
// A module is uninstantiated if it contains only
// 1. interface declarations, type alias declarations
if (node.kind === SyntaxKind.InterfaceDeclaration || node.kind === SyntaxKind.TypeAliasDeclaration) {
return ModuleInstanceState.NonInstantiated;
}
// 2. const enum declarations
else if (isConstEnumDeclaration(node)) {
return ModuleInstanceState.ConstEnumOnly;
}
// 3. non-exported import declarations
else if ((node.kind === SyntaxKind.ImportDeclaration || node.kind === SyntaxKind.ImportEqualsDeclaration) && !(hasModifier(node, ModifierFlags.Export))) {
return ModuleInstanceState.NonInstantiated;
}
// 4. other uninstantiated module declarations.
else if (node.kind === SyntaxKind.ModuleBlock) {
let state = ModuleInstanceState.NonInstantiated;
forEachChild(node, n => {
switch (getModuleInstanceState(n)) {
case ModuleInstanceState.NonInstantiated:
// child is non-instantiated - continue searching
return false;
case ModuleInstanceState.ConstEnumOnly:
// child is const enum only - record state and continue searching
state = ModuleInstanceState.ConstEnumOnly;
return false;
case ModuleInstanceState.Instantiated:
// child is instantiated - record state and stop
state = ModuleInstanceState.Instantiated;
return true;
}
});
return state;
}
else if (node.kind === SyntaxKind.ModuleDeclaration) {
const body = (<ModuleDeclaration>node).body;
return body ? getModuleInstanceState(body) : ModuleInstanceState.Instantiated;
}
else {
return ModuleInstanceState.Instantiated;
}
}
const enum ContainerFlags {
// The current node is not a container, and no container manipulation should happen before
// recursing into it.
None = 0,
// The current node is a container. It should be set as the current container (and block-
// container) before recursing into it. The current node does not have locals. Examples:
//
// Classes, ObjectLiterals, TypeLiterals, Interfaces...
IsContainer = 1 << 0,
// The current node is a block-scoped-container. It should be set as the current block-
// container before recursing into it. Examples:
//
// Blocks (when not parented by functions), Catch clauses, For/For-in/For-of statements...
IsBlockScopedContainer = 1 << 1,
// The current node is the container of a control flow path. The current control flow should
// be saved and restored, and a new control flow initialized within the container.
IsControlFlowContainer = 1 << 2,
IsFunctionLike = 1 << 3,
IsFunctionExpression = 1 << 4,
HasLocals = 1 << 5,
IsInterface = 1 << 6,
}
const binder = createBinder();
export function bindSourceFile(file: SourceFile, options: CompilerOptions) {
performance.mark("beforeBind");
binder(file, options);
performance.mark("afterBind");
performance.measure("Bind", "beforeBind", "afterBind");
}
function createBinder(): (file: SourceFile, options: CompilerOptions) => void {
let file: SourceFile;
let options: CompilerOptions;
let languageVersion: ScriptTarget;
let parent: Node;
let container: Node;
let blockScopeContainer: Node;
let lastContainer: Node;
let seenThisKeyword: boolean;
// state used by control flow analysis
let currentFlow: FlowNode;
let currentBreakTarget: FlowLabel;
let currentContinueTarget: FlowLabel;
let currentReturnTarget: FlowLabel;
let currentTrueTarget: FlowLabel;
let currentFalseTarget: FlowLabel;
let preSwitchCaseFlow: FlowNode;
let activeLabels: ActiveLabel[];
let hasExplicitReturn: boolean;
// state used for emit helpers
let emitFlags: NodeFlags;
// If this file is an external module, then it is automatically in strict-mode according to
// ES6. If it is not an external module, then we'll determine if it is in strict mode or
// not depending on if we see "use strict" in certain places (or if we hit a class/namespace).
let inStrictMode: boolean;
let symbolCount = 0;
let Symbol: { new (flags: SymbolFlags, name: string): Symbol };
let classifiableNames: Map<string>;
const unreachableFlow: FlowNode = { flags: FlowFlags.Unreachable };
const reportedUnreachableFlow: FlowNode = { flags: FlowFlags.Unreachable };
// state used to aggregate transform flags during bind.
let subtreeTransformFlags: TransformFlags = TransformFlags.None;
let skipTransformFlagAggregation: boolean;
function bindSourceFile(f: SourceFile, opts: CompilerOptions) {
file = f;
options = opts;
languageVersion = getEmitScriptTarget(options);
inStrictMode = !!file.externalModuleIndicator;
classifiableNames = createMap<string>();
symbolCount = 0;
skipTransformFlagAggregation = isDeclarationFile(file);
Symbol = objectAllocator.getSymbolConstructor();
if (!file.locals) {
bind(file);
file.symbolCount = symbolCount;
file.classifiableNames = classifiableNames;
}
file = undefined;
options = undefined;
languageVersion = undefined;
parent = undefined;
container = undefined;
blockScopeContainer = undefined;
lastContainer = undefined;
seenThisKeyword = false;
currentFlow = undefined;
currentBreakTarget = undefined;
currentContinueTarget = undefined;
currentReturnTarget = undefined;
currentTrueTarget = undefined;
currentFalseTarget = undefined;
activeLabels = undefined;
hasExplicitReturn = false;
emitFlags = NodeFlags.None;
subtreeTransformFlags = TransformFlags.None;
}
return bindSourceFile;
function createSymbol(flags: SymbolFlags, name: string): Symbol {
symbolCount++;
return new Symbol(flags, name);
}
function addDeclarationToSymbol(symbol: Symbol, node: Declaration, symbolFlags: SymbolFlags) {
symbol.flags |= symbolFlags;
node.symbol = symbol;
if (!symbol.declarations) {
symbol.declarations = [];
}
symbol.declarations.push(node);
if (symbolFlags & SymbolFlags.HasExports && !symbol.exports) {
symbol.exports = createMap<Symbol>();
}
if (symbolFlags & SymbolFlags.HasMembers && !symbol.members) {
symbol.members = createMap<Symbol>();
}
if (symbolFlags & SymbolFlags.Value) {
const valueDeclaration = symbol.valueDeclaration;
if (!valueDeclaration ||
(valueDeclaration.kind !== node.kind && valueDeclaration.kind === SyntaxKind.ModuleDeclaration)) {
// other kinds of value declarations take precedence over modules
symbol.valueDeclaration = node;
}
}
}
// Should not be called on a declaration with a computed property name,
// unless it is a well known Symbol.
function getDeclarationName(node: Declaration): string {
if (node.name) {
if (isAmbientModule(node)) {
return isGlobalScopeAugmentation(<ModuleDeclaration>node) ? "__global" : `"${(<LiteralExpression>node.name).text}"`;
}
if (node.name.kind === SyntaxKind.ComputedPropertyName) {
const nameExpression = (<ComputedPropertyName>node.name).expression;
// treat computed property names where expression is string/numeric literal as just string/numeric literal
if (isStringOrNumericLiteral(nameExpression.kind)) {
return (<LiteralExpression>nameExpression).text;
}
Debug.assert(isWellKnownSymbolSyntactically(nameExpression));
return getPropertyNameForKnownSymbolName((<PropertyAccessExpression>nameExpression).name.text);
}
return (<Identifier | LiteralExpression>node.name).text;
}
switch (node.kind) {
case SyntaxKind.Constructor:
return "__constructor";
case SyntaxKind.FunctionType:
case SyntaxKind.CallSignature:
return "__call";
case SyntaxKind.ConstructorType:
case SyntaxKind.ConstructSignature:
return "__new";
case SyntaxKind.IndexSignature:
return "__index";
case SyntaxKind.ExportDeclaration:
return "__export";
case SyntaxKind.ExportAssignment:
return (<ExportAssignment>node).isExportEquals ? "export=" : "default";
case SyntaxKind.BinaryExpression:
switch (getSpecialPropertyAssignmentKind(node)) {
case SpecialPropertyAssignmentKind.ModuleExports:
// module.exports = ...
return "export=";
case SpecialPropertyAssignmentKind.ExportsProperty:
case SpecialPropertyAssignmentKind.ThisProperty:
// exports.x = ... or this.y = ...
return ((node as BinaryExpression).left as PropertyAccessExpression).name.text;
case SpecialPropertyAssignmentKind.PrototypeProperty:
// className.prototype.methodName = ...
return (((node as BinaryExpression).left as PropertyAccessExpression).expression as PropertyAccessExpression).name.text;
}
Debug.fail("Unknown binary declaration kind");
break;
case SyntaxKind.FunctionDeclaration:
case SyntaxKind.ClassDeclaration:
return hasModifier(node, ModifierFlags.Default) ? "default" : undefined;
case SyntaxKind.JSDocFunctionType:
return isJSDocConstructSignature(node) ? "__new" : "__call";
case SyntaxKind.Parameter:
// Parameters with names are handled at the top of this function. Parameters
// without names can only come from JSDocFunctionTypes.
Debug.assert(node.parent.kind === SyntaxKind.JSDocFunctionType);
let functionType = <JSDocFunctionType>node.parent;
let index = indexOf(functionType.parameters, node);
return "arg" + index;
case SyntaxKind.JSDocTypedefTag:
const parentNode = node.parent && node.parent.parent;
let nameFromParentNode: string;
if (parentNode && parentNode.kind === SyntaxKind.VariableStatement) {
if ((<VariableStatement>parentNode).declarationList.declarations.length > 0) {
const nameIdentifier = (<VariableStatement>parentNode).declarationList.declarations[0].name;
if (nameIdentifier.kind === SyntaxKind.Identifier) {
nameFromParentNode = (<Identifier>nameIdentifier).text;
}
}
}
return nameFromParentNode;
}
}
function getDisplayName(node: Declaration): string {
return node.name ? declarationNameToString(node.name) : getDeclarationName(node);
}
/**
* Declares a Symbol for the node and adds it to symbols. Reports errors for conflicting identifier names.
* @param symbolTable - The symbol table which node will be added to.
* @param parent - node's parent declaration.
* @param node - The declaration to be added to the symbol table
* @param includes - The SymbolFlags that node has in addition to its declaration type (eg: export, ambient, etc.)
* @param excludes - The flags which node cannot be declared alongside in a symbol table. Used to report forbidden declarations.
*/
function declareSymbol(symbolTable: SymbolTable, parent: Symbol, node: Declaration, includes: SymbolFlags, excludes: SymbolFlags): Symbol {
Debug.assert(!hasDynamicName(node));
const isDefaultExport = hasModifier(node, ModifierFlags.Default);
// The exported symbol for an export default function/class node is always named "default"
const name = isDefaultExport && parent ? "default" : getDeclarationName(node);
let symbol: Symbol;
if (name === undefined) {
symbol = createSymbol(SymbolFlags.None, "__missing");
}
else {
// Check and see if the symbol table already has a symbol with this name. If not,
// create a new symbol with this name and add it to the table. Note that we don't
// give the new symbol any flags *yet*. This ensures that it will not conflict
// with the 'excludes' flags we pass in.
//
// If we do get an existing symbol, see if it conflicts with the new symbol we're
// creating. For example, a 'var' symbol and a 'class' symbol will conflict within
// the same symbol table. If we have a conflict, report the issue on each
// declaration we have for this symbol, and then create a new symbol for this
// declaration.
//
// Note that when properties declared in Javascript constructors
// (marked by isReplaceableByMethod) conflict with another symbol, the property loses.
// Always. This allows the common Javascript pattern of overwriting a prototype method
// with an bound instance method of the same type: `this.method = this.method.bind(this)`
//
// If we created a new symbol, either because we didn't have a symbol with this name
// in the symbol table, or we conflicted with an existing symbol, then just add this
// node as the sole declaration of the new symbol.
//
// Otherwise, we'll be merging into a compatible existing symbol (for example when
// you have multiple 'vars' with the same name in the same container). In this case
// just add this node into the declarations list of the symbol.
symbol = symbolTable[name] || (symbolTable[name] = createSymbol(SymbolFlags.None, name));
if (name && (includes & SymbolFlags.Classifiable)) {
classifiableNames[name] = name;
}
if (symbol.flags & excludes) {
if (symbol.isReplaceableByMethod) {
// Javascript constructor-declared symbols can be discarded in favor of
// prototype symbols like methods.
symbol = symbolTable[name] = createSymbol(SymbolFlags.None, name);
}
else {
if (node.name) {
node.name.parent = node;
}
// Report errors every position with duplicate declaration
// Report errors on previous encountered declarations
let message = symbol.flags & SymbolFlags.BlockScopedVariable
? Diagnostics.Cannot_redeclare_block_scoped_variable_0
: Diagnostics.Duplicate_identifier_0;
forEach(symbol.declarations, declaration => {
if (hasModifier(declaration, ModifierFlags.Default)) {
message = Diagnostics.A_module_cannot_have_multiple_default_exports;
}
});
forEach(symbol.declarations, declaration => {
file.bindDiagnostics.push(createDiagnosticForNode(declaration.name || declaration, message, getDisplayName(declaration)));
});
file.bindDiagnostics.push(createDiagnosticForNode(node.name || node, message, getDisplayName(node)));
symbol = createSymbol(SymbolFlags.None, name);
}
}
}
addDeclarationToSymbol(symbol, node, includes);
symbol.parent = parent;
return symbol;
}
function declareModuleMember(node: Declaration, symbolFlags: SymbolFlags, symbolExcludes: SymbolFlags): Symbol {
const hasExportModifier = getCombinedModifierFlags(node) & ModifierFlags.Export;
if (symbolFlags & SymbolFlags.Alias) {
if (node.kind === SyntaxKind.ExportSpecifier || (node.kind === SyntaxKind.ImportEqualsDeclaration && hasExportModifier)) {
return declareSymbol(container.symbol.exports, container.symbol, node, symbolFlags, symbolExcludes);
}
else {
return declareSymbol(container.locals, undefined, node, symbolFlags, symbolExcludes);
}
}
else {
// Exported module members are given 2 symbols: A local symbol that is classified with an ExportValue,
// ExportType, or ExportContainer flag, and an associated export symbol with all the correct flags set
// on it. There are 2 main reasons:
//
// 1. We treat locals and exports of the same name as mutually exclusive within a container.
// That means the binder will issue a Duplicate Identifier error if you mix locals and exports
// with the same name in the same container.
// TODO: Make this a more specific error and decouple it from the exclusion logic.
// 2. When we checkIdentifier in the checker, we set its resolved symbol to the local symbol,
// but return the export symbol (by calling getExportSymbolOfValueSymbolIfExported). That way
// when the emitter comes back to it, it knows not to qualify the name if it was found in a containing scope.
// NOTE: Nested ambient modules always should go to to 'locals' table to prevent their automatic merge
// during global merging in the checker. Why? The only case when ambient module is permitted inside another module is module augmentation
// and this case is specially handled. Module augmentations should only be merged with original module definition
// and should never be merged directly with other augmentation, and the latter case would be possible if automatic merge is allowed.
if (!isAmbientModule(node) && (hasExportModifier || container.flags & NodeFlags.ExportContext)) {
const exportKind =
(symbolFlags & SymbolFlags.Value ? SymbolFlags.ExportValue : 0) |
(symbolFlags & SymbolFlags.Type ? SymbolFlags.ExportType : 0) |
(symbolFlags & SymbolFlags.Namespace ? SymbolFlags.ExportNamespace : 0);
const local = declareSymbol(container.locals, undefined, node, exportKind, symbolExcludes);
local.exportSymbol = declareSymbol(container.symbol.exports, container.symbol, node, symbolFlags, symbolExcludes);
node.localSymbol = local;
return local;
}
else {
return declareSymbol(container.locals, undefined, node, symbolFlags, symbolExcludes);
}
}
}
// All container nodes are kept on a linked list in declaration order. This list is used by
// the getLocalNameOfContainer function in the type checker to validate that the local name
// used for a container is unique.
function bindContainer(node: Node, containerFlags: ContainerFlags) {
// Before we recurse into a node's children, we first save the existing parent, container
// and block-container. Then after we pop out of processing the children, we restore
// these saved values.
const saveContainer = container;
const savedBlockScopeContainer = blockScopeContainer;
// Depending on what kind of node this is, we may have to adjust the current container
// and block-container. If the current node is a container, then it is automatically
// considered the current block-container as well. Also, for containers that we know
// may contain locals, we proactively initialize the .locals field. We do this because
// it's highly likely that the .locals will be needed to place some child in (for example,
// a parameter, or variable declaration).
//
// However, we do not proactively create the .locals for block-containers because it's
// totally normal and common for block-containers to never actually have a block-scoped
// variable in them. We don't want to end up allocating an object for every 'block' we
// run into when most of them won't be necessary.
//
// Finally, if this is a block-container, then we clear out any existing .locals object
// it may contain within it. This happens in incremental scenarios. Because we can be
// reusing a node from a previous compilation, that node may have had 'locals' created
// for it. We must clear this so we don't accidentally move any stale data forward from
// a previous compilation.
if (containerFlags & ContainerFlags.IsContainer) {
container = blockScopeContainer = node;
if (containerFlags & ContainerFlags.HasLocals) {
container.locals = createMap<Symbol>();
}
addToContainerChain(container);
}
else if (containerFlags & ContainerFlags.IsBlockScopedContainer) {
blockScopeContainer = node;
blockScopeContainer.locals = undefined;
}
if (containerFlags & ContainerFlags.IsControlFlowContainer) {
const saveCurrentFlow = currentFlow;
const saveBreakTarget = currentBreakTarget;
const saveContinueTarget = currentContinueTarget;
const saveReturnTarget = currentReturnTarget;
const saveActiveLabels = activeLabels;
const saveHasExplicitReturn = hasExplicitReturn;
const isIIFE = containerFlags & ContainerFlags.IsFunctionExpression && !!getImmediatelyInvokedFunctionExpression(node);
// An IIFE is considered part of the containing control flow. Return statements behave
// similarly to break statements that exit to a label just past the statement body.
if (isIIFE) {
currentReturnTarget = createBranchLabel();
}
else {
currentFlow = { flags: FlowFlags.Start };
if (containerFlags & ContainerFlags.IsFunctionExpression) {
(<FlowStart>currentFlow).container = <FunctionExpression | ArrowFunction>node;
}
currentReturnTarget = undefined;
}
currentBreakTarget = undefined;
currentContinueTarget = undefined;
activeLabels = undefined;
hasExplicitReturn = false;
bindChildren(node);
// Reset all reachability check related flags on node (for incremental scenarios)
// Reset all emit helper flags on node (for incremental scenarios)
node.flags &= ~NodeFlags.ReachabilityAndEmitFlags;
if (!(currentFlow.flags & FlowFlags.Unreachable) && containerFlags & ContainerFlags.IsFunctionLike && nodeIsPresent((<FunctionLikeDeclaration>node).body)) {
node.flags |= NodeFlags.HasImplicitReturn;
if (hasExplicitReturn) node.flags |= NodeFlags.HasExplicitReturn;
}
if (node.kind === SyntaxKind.SourceFile) {
node.flags |= emitFlags;
}
if (isIIFE) {
addAntecedent(currentReturnTarget, currentFlow);
currentFlow = finishFlowLabel(currentReturnTarget);
}
else {
currentFlow = saveCurrentFlow;
}
currentBreakTarget = saveBreakTarget;
currentContinueTarget = saveContinueTarget;
currentReturnTarget = saveReturnTarget;
activeLabels = saveActiveLabels;
hasExplicitReturn = saveHasExplicitReturn;
}
else if (containerFlags & ContainerFlags.IsInterface) {
seenThisKeyword = false;
bindChildren(node);
node.flags = seenThisKeyword ? node.flags | NodeFlags.ContainsThis : node.flags & ~NodeFlags.ContainsThis;
}
else {
bindChildren(node);
}
container = saveContainer;
blockScopeContainer = savedBlockScopeContainer;
}
function bindChildren(node: Node): void {
if (skipTransformFlagAggregation) {
bindChildrenWorker(node);
}
else if (node.transformFlags & TransformFlags.HasComputedFlags) {
skipTransformFlagAggregation = true;
bindChildrenWorker(node);
skipTransformFlagAggregation = false;
}
else {
const savedSubtreeTransformFlags = subtreeTransformFlags;
subtreeTransformFlags = 0;
bindChildrenWorker(node);
subtreeTransformFlags = savedSubtreeTransformFlags | computeTransformFlagsForNode(node, subtreeTransformFlags);
}
}
function bindChildrenWorker(node: Node): void {
// Binding of JsDocComment should be done before the current block scope container changes.
// because the scope of JsDocComment should not be affected by whether the current node is a
// container or not.
if (isInJavaScriptFile(node) && node.jsDocComments) {
forEach(node.jsDocComments, bind);
}
if (checkUnreachable(node)) {
forEachChild(node, bind);
return;
}
switch (node.kind) {
case SyntaxKind.WhileStatement:
bindWhileStatement(<WhileStatement>node);
break;
case SyntaxKind.DoStatement:
bindDoStatement(<DoStatement>node);
break;
case SyntaxKind.ForStatement:
bindForStatement(<ForStatement>node);
break;
case SyntaxKind.ForInStatement:
case SyntaxKind.ForOfStatement:
bindForInOrForOfStatement(<ForInStatement | ForOfStatement>node);
break;
case SyntaxKind.IfStatement:
bindIfStatement(<IfStatement>node);
break;
case SyntaxKind.ReturnStatement:
case SyntaxKind.ThrowStatement:
bindReturnOrThrow(<ReturnStatement | ThrowStatement>node);
break;
case SyntaxKind.BreakStatement:
case SyntaxKind.ContinueStatement:
bindBreakOrContinueStatement(<BreakOrContinueStatement>node);
break;
case SyntaxKind.TryStatement:
bindTryStatement(<TryStatement>node);
break;
case SyntaxKind.SwitchStatement:
bindSwitchStatement(<SwitchStatement>node);
break;
case SyntaxKind.CaseBlock:
bindCaseBlock(<CaseBlock>node);
break;
case SyntaxKind.CaseClause:
bindCaseClause(<CaseClause>node);
break;
case SyntaxKind.LabeledStatement:
bindLabeledStatement(<LabeledStatement>node);
break;
case SyntaxKind.PrefixUnaryExpression:
bindPrefixUnaryExpressionFlow(<PrefixUnaryExpression>node);
break;
case SyntaxKind.PostfixUnaryExpression:
bindPostfixUnaryExpressionFlow(<PostfixUnaryExpression>node);
break;
case SyntaxKind.BinaryExpression:
bindBinaryExpressionFlow(<BinaryExpression>node);
break;
case SyntaxKind.DeleteExpression:
bindDeleteExpressionFlow(<DeleteExpression>node);
break;
case SyntaxKind.ConditionalExpression:
bindConditionalExpressionFlow(<ConditionalExpression>node);
break;
case SyntaxKind.VariableDeclaration:
bindVariableDeclarationFlow(<VariableDeclaration>node);
break;
case SyntaxKind.CallExpression:
bindCallExpressionFlow(<CallExpression>node);
break;
default:
forEachChild(node, bind);
break;
}
}
function isNarrowingExpression(expr: Expression): boolean {
switch (expr.kind) {
case SyntaxKind.Identifier:
case SyntaxKind.ThisKeyword:
case SyntaxKind.PropertyAccessExpression:
return isNarrowableReference(expr);
case SyntaxKind.CallExpression:
return hasNarrowableArgument(<CallExpression>expr);
case SyntaxKind.ParenthesizedExpression:
return isNarrowingExpression((<ParenthesizedExpression>expr).expression);
case SyntaxKind.BinaryExpression:
return isNarrowingBinaryExpression(<BinaryExpression>expr);
case SyntaxKind.PrefixUnaryExpression:
return (<PrefixUnaryExpression>expr).operator === SyntaxKind.ExclamationToken && isNarrowingExpression((<PrefixUnaryExpression>expr).operand);
}
return false;
}
function isNarrowableReference(expr: Expression): boolean {
return expr.kind === SyntaxKind.Identifier ||
expr.kind === SyntaxKind.ThisKeyword ||
expr.kind === SyntaxKind.PropertyAccessExpression && isNarrowableReference((<PropertyAccessExpression>expr).expression);
}
function hasNarrowableArgument(expr: CallExpression) {
if (expr.arguments) {
for (const argument of expr.arguments) {
if (isNarrowableReference(argument)) {
return true;
}
}
}
if (expr.expression.kind === SyntaxKind.PropertyAccessExpression &&
isNarrowableReference((<PropertyAccessExpression>expr.expression).expression)) {
return true;
}
return false;
}
function isNarrowingTypeofOperands(expr1: Expression, expr2: Expression) {
return expr1.kind === SyntaxKind.TypeOfExpression && isNarrowableOperand((<TypeOfExpression>expr1).expression) && expr2.kind === SyntaxKind.StringLiteral;
}
function isNarrowingBinaryExpression(expr: BinaryExpression) {
switch (expr.operatorToken.kind) {
case SyntaxKind.EqualsToken:
return isNarrowableReference(expr.left);
case SyntaxKind.EqualsEqualsToken:
case SyntaxKind.ExclamationEqualsToken:
case SyntaxKind.EqualsEqualsEqualsToken:
case SyntaxKind.ExclamationEqualsEqualsToken:
return isNarrowableOperand(expr.left) || isNarrowableOperand(expr.right) ||
isNarrowingTypeofOperands(expr.right, expr.left) || isNarrowingTypeofOperands(expr.left, expr.right);
case SyntaxKind.InstanceOfKeyword:
return isNarrowableOperand(expr.left);
case SyntaxKind.CommaToken:
return isNarrowingExpression(expr.right);
}
return false;
}
function isNarrowableOperand(expr: Expression): boolean {
switch (expr.kind) {
case SyntaxKind.ParenthesizedExpression:
return isNarrowableOperand((<ParenthesizedExpression>expr).expression);
case SyntaxKind.BinaryExpression:
switch ((<BinaryExpression>expr).operatorToken.kind) {
case SyntaxKind.EqualsToken:
return isNarrowableOperand((<BinaryExpression>expr).left);
case SyntaxKind.CommaToken:
return isNarrowableOperand((<BinaryExpression>expr).right);
}
}
return isNarrowableReference(expr);
}
function createBranchLabel(): FlowLabel {
return {
flags: FlowFlags.BranchLabel,
antecedents: undefined
};
}
function createLoopLabel(): FlowLabel {
return {
flags: FlowFlags.LoopLabel,
antecedents: undefined
};
}
function setFlowNodeReferenced(flow: FlowNode) {
// On first reference we set the Referenced flag, thereafter we set the Shared flag
flow.flags |= flow.flags & FlowFlags.Referenced ? FlowFlags.Shared : FlowFlags.Referenced;
}
function addAntecedent(label: FlowLabel, antecedent: FlowNode): void {
if (!(antecedent.flags & FlowFlags.Unreachable) && !contains(label.antecedents, antecedent)) {
(label.antecedents || (label.antecedents = [])).push(antecedent);
setFlowNodeReferenced(antecedent);
}
}
function createFlowCondition(flags: FlowFlags, antecedent: FlowNode, expression: Expression): FlowNode {
if (antecedent.flags & FlowFlags.Unreachable) {
return antecedent;
}
if (!expression) {
return flags & FlowFlags.TrueCondition ? antecedent : unreachableFlow;
}
if (expression.kind === SyntaxKind.TrueKeyword && flags & FlowFlags.FalseCondition ||
expression.kind === SyntaxKind.FalseKeyword && flags & FlowFlags.TrueCondition) {
return unreachableFlow;
}
if (!isNarrowingExpression(expression)) {
return antecedent;
}
setFlowNodeReferenced(antecedent);
return <FlowCondition>{
flags,
expression,
antecedent
};
}
function createFlowSwitchClause(antecedent: FlowNode, switchStatement: SwitchStatement, clauseStart: number, clauseEnd: number): FlowNode {
if (!isNarrowingExpression(switchStatement.expression)) {
return antecedent;
}
setFlowNodeReferenced(antecedent);
return <FlowSwitchClause>{
flags: FlowFlags.SwitchClause,
switchStatement,
clauseStart,
clauseEnd,
antecedent
};
}
function createFlowAssignment(antecedent: FlowNode, node: Expression | VariableDeclaration | BindingElement): FlowNode {
setFlowNodeReferenced(antecedent);
return <FlowAssignment>{
flags: FlowFlags.Assignment,
antecedent,
node
};
}
function finishFlowLabel(flow: FlowLabel): FlowNode {
const antecedents = flow.antecedents;
if (!antecedents) {
return unreachableFlow;
}
if (antecedents.length === 1) {
return antecedents[0];
}
return flow;
}
function isStatementCondition(node: Node) {
const parent = node.parent;
switch (parent.kind) {
case SyntaxKind.IfStatement:
case SyntaxKind.WhileStatement:
case SyntaxKind.DoStatement:
return (<IfStatement | WhileStatement | DoStatement>parent).expression === node;
case SyntaxKind.ForStatement:
case SyntaxKind.ConditionalExpression:
return (<ForStatement | ConditionalExpression>parent).condition === node;
}
return false;
}
function isLogicalExpression(node: Node) {
while (true) {
if (node.kind === SyntaxKind.ParenthesizedExpression) {
node = (<ParenthesizedExpression>node).expression;
}
else if (node.kind === SyntaxKind.PrefixUnaryExpression && (<PrefixUnaryExpression>node).operator === SyntaxKind.ExclamationToken) {
node = (<PrefixUnaryExpression>node).operand;
}
else {
return node.kind === SyntaxKind.BinaryExpression && (
(<BinaryExpression>node).operatorToken.kind === SyntaxKind.AmpersandAmpersandToken ||
(<BinaryExpression>node).operatorToken.kind === SyntaxKind.BarBarToken);
}
}
}
function isTopLevelLogicalExpression(node: Node): boolean {
while (node.parent.kind === SyntaxKind.ParenthesizedExpression ||
node.parent.kind === SyntaxKind.PrefixUnaryExpression &&
(<PrefixUnaryExpression>node.parent).operator === SyntaxKind.ExclamationToken) {
node = node.parent;
}
return !isStatementCondition(node) && !isLogicalExpression(node.parent);
}
function bindCondition(node: Expression, trueTarget: FlowLabel, falseTarget: FlowLabel) {
const saveTrueTarget = currentTrueTarget;
const saveFalseTarget = currentFalseTarget;
currentTrueTarget = trueTarget;
currentFalseTarget = falseTarget;
bind(node);
currentTrueTarget = saveTrueTarget;
currentFalseTarget = saveFalseTarget;
if (!node || !isLogicalExpression(node)) {
addAntecedent(trueTarget, createFlowCondition(FlowFlags.TrueCondition, currentFlow, node));
addAntecedent(falseTarget, createFlowCondition(FlowFlags.FalseCondition, currentFlow, node));
}
}
function bindIterativeStatement(node: Statement, breakTarget: FlowLabel, continueTarget: FlowLabel): void {
const saveBreakTarget = currentBreakTarget;
const saveContinueTarget = currentContinueTarget;
currentBreakTarget = breakTarget;
currentContinueTarget = continueTarget;
bind(node);
currentBreakTarget = saveBreakTarget;
currentContinueTarget = saveContinueTarget;
}
function bindWhileStatement(node: WhileStatement): void {
const preWhileLabel = createLoopLabel();
const preBodyLabel = createBranchLabel();
const postWhileLabel = createBranchLabel();
addAntecedent(preWhileLabel, currentFlow);
currentFlow = preWhileLabel;
bindCondition(node.expression, preBodyLabel, postWhileLabel);
currentFlow = finishFlowLabel(preBodyLabel);
bindIterativeStatement(node.statement, postWhileLabel, preWhileLabel);
addAntecedent(preWhileLabel, currentFlow);
currentFlow = finishFlowLabel(postWhileLabel);
}
function bindDoStatement(node: DoStatement): void {
const preDoLabel = createLoopLabel();
const preConditionLabel = createBranchLabel();
const postDoLabel = createBranchLabel();
addAntecedent(preDoLabel, currentFlow);
currentFlow = preDoLabel;
bindIterativeStatement(node.statement, postDoLabel, preConditionLabel);
addAntecedent(preConditionLabel, currentFlow);
currentFlow = finishFlowLabel(preConditionLabel);
bindCondition(node.expression, preDoLabel, postDoLabel);
currentFlow = finishFlowLabel(postDoLabel);
}
function bindForStatement(node: ForStatement): void {
const preLoopLabel = createLoopLabel();
const preBodyLabel = createBranchLabel();
const postLoopLabel = createBranchLabel();
bind(node.initializer);
addAntecedent(preLoopLabel, currentFlow);
currentFlow = preLoopLabel;
bindCondition(node.condition, preBodyLabel, postLoopLabel);
currentFlow = finishFlowLabel(preBodyLabel);
bindIterativeStatement(node.statement, postLoopLabel, preLoopLabel);
bind(node.incrementor);
addAntecedent(preLoopLabel, currentFlow);
currentFlow = finishFlowLabel(postLoopLabel);
}
function bindForInOrForOfStatement(node: ForInStatement | ForOfStatement): void {
const preLoopLabel = createLoopLabel();
const postLoopLabel = createBranchLabel();
addAntecedent(preLoopLabel, currentFlow);
currentFlow = preLoopLabel;
bind(node.expression);
addAntecedent(postLoopLabel, currentFlow);
bind(node.initializer);
if (node.initializer.kind !== SyntaxKind.VariableDeclarationList) {
bindAssignmentTargetFlow(<Expression>node.initializer);
}
bindIterativeStatement(node.statement, postLoopLabel, preLoopLabel);
addAntecedent(preLoopLabel, currentFlow);
currentFlow = finishFlowLabel(postLoopLabel);
}
function bindIfStatement(node: IfStatement): void {
const thenLabel = createBranchLabel();
const elseLabel = createBranchLabel();
const postIfLabel = createBranchLabel();
bindCondition(node.expression, thenLabel, elseLabel);
currentFlow = finishFlowLabel(thenLabel);
bind(node.thenStatement);
addAntecedent(postIfLabel, currentFlow);
currentFlow = finishFlowLabel(elseLabel);
bind(node.elseStatement);
addAntecedent(postIfLabel, currentFlow);
currentFlow = finishFlowLabel(postIfLabel);
}
function bindReturnOrThrow(node: ReturnStatement | ThrowStatement): void {
bind(node.expression);
if (node.kind === SyntaxKind.ReturnStatement) {
hasExplicitReturn = true;
if (currentReturnTarget) {
addAntecedent(currentReturnTarget, currentFlow);
}
}
currentFlow = unreachableFlow;
}
function findActiveLabel(name: string) {
if (activeLabels) {
for (const label of activeLabels) {
if (label.name === name) {
return label;
}
}
}
return undefined;
}
function bindbreakOrContinueFlow(node: BreakOrContinueStatement, breakTarget: FlowLabel, continueTarget: FlowLabel) {
const flowLabel = node.kind === SyntaxKind.BreakStatement ? breakTarget : continueTarget;
if (flowLabel) {
addAntecedent(flowLabel, currentFlow);
currentFlow = unreachableFlow;
}
}
function bindBreakOrContinueStatement(node: BreakOrContinueStatement): void {
bind(node.label);
if (node.label) {
const activeLabel = findActiveLabel(node.label.text);
if (activeLabel) {
activeLabel.referenced = true;
bindbreakOrContinueFlow(node, activeLabel.breakTarget, activeLabel.continueTarget);
}
}
else {
bindbreakOrContinueFlow(node, currentBreakTarget, currentContinueTarget);
}
}
function bindTryStatement(node: TryStatement): void {
const postFinallyLabel = createBranchLabel();
const preTryFlow = currentFlow;
// TODO: Every statement in try block is potentially an exit point!
bind(node.tryBlock);
addAntecedent(postFinallyLabel, currentFlow);
if (node.catchClause) {
currentFlow = preTryFlow;
bind(node.catchClause);
addAntecedent(postFinallyLabel, currentFlow);
}
if (node.finallyBlock) {
currentFlow = preTryFlow;
bind(node.finallyBlock);
}
// if try statement has finally block and flow after finally block is unreachable - keep it
// otherwise use whatever flow was accumulated at postFinallyLabel
if (!node.finallyBlock || !(currentFlow.flags & FlowFlags.Unreachable)) {
currentFlow = finishFlowLabel(postFinallyLabel);
}
}
function bindSwitchStatement(node: SwitchStatement): void {
const postSwitchLabel = createBranchLabel();
bind(node.expression);
const saveBreakTarget = currentBreakTarget;
const savePreSwitchCaseFlow = preSwitchCaseFlow;
currentBreakTarget = postSwitchLabel;
preSwitchCaseFlow = currentFlow;
bind(node.caseBlock);
addAntecedent(postSwitchLabel, currentFlow);
const hasDefault = forEach(node.caseBlock.clauses, c => c.kind === SyntaxKind.DefaultClause);
// We mark a switch statement as possibly exhaustive if it has no default clause and if all
// case clauses have unreachable end points (e.g. they all return).
node.possiblyExhaustive = !hasDefault && !postSwitchLabel.antecedents;
if (!hasDefault) {
addAntecedent(postSwitchLabel, createFlowSwitchClause(preSwitchCaseFlow, node, 0, 0));
}
currentBreakTarget = saveBreakTarget;
preSwitchCaseFlow = savePreSwitchCaseFlow;
currentFlow = finishFlowLabel(postSwitchLabel);
}
function bindCaseBlock(node: CaseBlock): void {
const clauses = node.clauses;
let fallthroughFlow = unreachableFlow;
for (let i = 0; i < clauses.length; i++) {
const clauseStart = i;
while (!clauses[i].statements.length && i + 1 < clauses.length) {