From 26105034da4fcce7ac883c899d781f016559310d Mon Sep 17 00:00:00 2001 From: ruki Date: Thu, 8 Nov 2018 00:38:48 +0800 Subject: switch to vuepress --- node_modules/regenerator-transform/src/emit.js | 1207 ++++++++++++++++++++++++ 1 file changed, 1207 insertions(+) create mode 100644 node_modules/regenerator-transform/src/emit.js (limited to 'node_modules/regenerator-transform/src/emit.js') diff --git a/node_modules/regenerator-transform/src/emit.js b/node_modules/regenerator-transform/src/emit.js new file mode 100644 index 00000000..040faec3 --- /dev/null +++ b/node_modules/regenerator-transform/src/emit.js @@ -0,0 +1,1207 @@ +/** + * Copyright (c) 2014-present, Facebook, Inc. + * + * This source code is licensed under the MIT license found in the + * LICENSE file in the root directory of this source tree. + */ + +import assert from "assert"; +import * as leap from "./leap"; +import * as meta from "./meta"; +import * as util from "./util"; + +let hasOwn = Object.prototype.hasOwnProperty; + +function Emitter(contextId) { + assert.ok(this instanceof Emitter); + + util.getTypes().assertIdentifier(contextId); + + // Used to generate unique temporary names. + this.nextTempId = 0; + + // In order to make sure the context object does not collide with + // anything in the local scope, we might have to rename it, so we + // refer to it symbolically instead of just assuming that it will be + // called "context". + this.contextId = contextId; + + // An append-only list of Statements that grows each time this.emit is + // called. + this.listing = []; + + // A sparse array whose keys correspond to locations in this.listing + // that have been marked as branch/jump targets. + this.marked = [true]; + + // The last location will be marked when this.getDispatchLoop is + // called. + this.finalLoc = loc(); + + // A list of all leap.TryEntry statements emitted. + this.tryEntries = []; + + // Each time we evaluate the body of a loop, we tell this.leapManager + // to enter a nested loop context that determines the meaning of break + // and continue statements therein. + this.leapManager = new leap.LeapManager(this); +} + +let Ep = Emitter.prototype; +exports.Emitter = Emitter; + +// Offsets into this.listing that could be used as targets for branches or +// jumps are represented as numeric Literal nodes. This representation has +// the amazingly convenient benefit of allowing the exact value of the +// location to be determined at any time, even after generating code that +// refers to the location. +function loc() { + return util.getTypes().numericLiteral(-1); +} + +// Sets the exact value of the given location to the offset of the next +// Statement emitted. +Ep.mark = function(loc) { + util.getTypes().assertLiteral(loc); + let index = this.listing.length; + if (loc.value === -1) { + loc.value = index; + } else { + // Locations can be marked redundantly, but their values cannot change + // once set the first time. + assert.strictEqual(loc.value, index); + } + this.marked[index] = true; + return loc; +}; + +Ep.emit = function(node) { + const t = util.getTypes(); + + if (t.isExpression(node)) { + node = t.expressionStatement(node); + } + + t.assertStatement(node); + this.listing.push(node); +}; + +// Shorthand for emitting assignment statements. This will come in handy +// for assignments to temporary variables. +Ep.emitAssign = function(lhs, rhs) { + this.emit(this.assign(lhs, rhs)); + return lhs; +}; + +// Shorthand for an assignment statement. +Ep.assign = function(lhs, rhs) { + const t = util.getTypes(); + return t.expressionStatement( + t.assignmentExpression("=", lhs, rhs)); +}; + +// Convenience function for generating expressions like context.next, +// context.sent, and context.rval. +Ep.contextProperty = function(name, computed) { + const t = util.getTypes(); + return t.memberExpression( + this.contextId, + computed ? t.stringLiteral(name) : t.identifier(name), + !!computed + ); +}; + +// Shorthand for setting context.rval and jumping to `context.stop()`. +Ep.stop = function(rval) { + if (rval) { + this.setReturnValue(rval); + } + + this.jump(this.finalLoc); +}; + +Ep.setReturnValue = function(valuePath) { + util.getTypes().assertExpression(valuePath.value); + + this.emitAssign( + this.contextProperty("rval"), + this.explodeExpression(valuePath) + ); +}; + +Ep.clearPendingException = function(tryLoc, assignee) { + const t = util.getTypes(); + + t.assertLiteral(tryLoc); + + let catchCall = t.callExpression( + this.contextProperty("catch", true), + [tryLoc] + ); + + if (assignee) { + this.emitAssign(assignee, catchCall); + } else { + this.emit(catchCall); + } +}; + +// Emits code for an unconditional jump to the given location, even if the +// exact value of the location is not yet known. +Ep.jump = function(toLoc) { + this.emitAssign(this.contextProperty("next"), toLoc); + this.emit(util.getTypes().breakStatement()); +}; + +// Conditional jump. +Ep.jumpIf = function(test, toLoc) { + const t = util.getTypes(); + + t.assertExpression(test); + t.assertLiteral(toLoc); + + this.emit(t.ifStatement( + test, + t.blockStatement([ + this.assign(this.contextProperty("next"), toLoc), + t.breakStatement() + ]) + )); +}; + +// Conditional jump, with the condition negated. +Ep.jumpIfNot = function(test, toLoc) { + const t = util.getTypes(); + + t.assertExpression(test); + t.assertLiteral(toLoc); + + let negatedTest; + if (t.isUnaryExpression(test) && + test.operator === "!") { + // Avoid double negation. + negatedTest = test.argument; + } else { + negatedTest = t.unaryExpression("!", test); + } + + this.emit(t.ifStatement( + negatedTest, + t.blockStatement([ + this.assign(this.contextProperty("next"), toLoc), + t.breakStatement() + ]) + )); +}; + +// Returns a unique MemberExpression that can be used to store and +// retrieve temporary values. Since the object of the member expression is +// the context object, which is presumed to coexist peacefully with all +// other local variables, and since we just increment `nextTempId` +// monotonically, uniqueness is assured. +Ep.makeTempVar = function() { + return this.contextProperty("t" + this.nextTempId++); +}; + +Ep.getContextFunction = function(id) { + const t = util.getTypes(); + + return t.functionExpression( + id || null/*Anonymous*/, + [this.contextId], + t.blockStatement([this.getDispatchLoop()]), + false, // Not a generator anymore! + false // Nor an expression. + ); +}; + +// Turns this.listing into a loop of the form +// +// while (1) switch (context.next) { +// case 0: +// ... +// case n: +// return context.stop(); +// } +// +// Each marked location in this.listing will correspond to one generated +// case statement. +Ep.getDispatchLoop = function() { + const self = this; + const t = util.getTypes(); + let cases = []; + let current; + + // If we encounter a break, continue, or return statement in a switch + // case, we can skip the rest of the statements until the next case. + let alreadyEnded = false; + + self.listing.forEach(function(stmt, i) { + if (self.marked.hasOwnProperty(i)) { + cases.push(t.switchCase( + t.numericLiteral(i), + current = [])); + alreadyEnded = false; + } + + if (!alreadyEnded) { + current.push(stmt); + if (t.isCompletionStatement(stmt)) + alreadyEnded = true; + } + }); + + // Now that we know how many statements there will be in this.listing, + // we can finally resolve this.finalLoc.value. + this.finalLoc.value = this.listing.length; + + cases.push( + t.switchCase(this.finalLoc, [ + // Intentionally fall through to the "end" case... + ]), + + // So that the runtime can jump to the final location without having + // to know its offset, we provide the "end" case as a synonym. + t.switchCase(t.stringLiteral("end"), [ + // This will check/clear both context.thrown and context.rval. + t.returnStatement( + t.callExpression(this.contextProperty("stop"), []) + ) + ]) + ); + + return t.whileStatement( + t.numericLiteral(1), + t.switchStatement( + t.assignmentExpression( + "=", + this.contextProperty("prev"), + this.contextProperty("next") + ), + cases + ) + ); +}; + +Ep.getTryLocsList = function() { + if (this.tryEntries.length === 0) { + // To avoid adding a needless [] to the majority of runtime.wrap + // argument lists, force the caller to handle this case specially. + return null; + } + + const t = util.getTypes(); + let lastLocValue = 0; + + return t.arrayExpression( + this.tryEntries.map(function(tryEntry) { + let thisLocValue = tryEntry.firstLoc.value; + assert.ok(thisLocValue >= lastLocValue, "try entries out of order"); + lastLocValue = thisLocValue; + + let ce = tryEntry.catchEntry; + let fe = tryEntry.finallyEntry; + + let locs = [ + tryEntry.firstLoc, + // The null here makes a hole in the array. + ce ? ce.firstLoc : null + ]; + + if (fe) { + locs[2] = fe.firstLoc; + locs[3] = fe.afterLoc; + } + + return t.arrayExpression(locs); + }) + ); +}; + +// All side effects must be realized in order. + +// If any subexpression harbors a leap, all subexpressions must be +// neutered of side effects. + +// No destructive modification of AST nodes. + +Ep.explode = function(path, ignoreResult) { + const t = util.getTypes(); + let node = path.node; + let self = this; + + t.assertNode(node); + + if (t.isDeclaration(node)) + throw getDeclError(node); + + if (t.isStatement(node)) + return self.explodeStatement(path); + + if (t.isExpression(node)) + return self.explodeExpression(path, ignoreResult); + + switch (node.type) { + case "Program": + return path.get("body").map( + self.explodeStatement, + self + ); + + case "VariableDeclarator": + throw getDeclError(node); + + // These node types should be handled by their parent nodes + // (ObjectExpression, SwitchStatement, and TryStatement, respectively). + case "Property": + case "SwitchCase": + case "CatchClause": + throw new Error( + node.type + " nodes should be handled by their parents"); + + default: + throw new Error( + "unknown Node of type " + + JSON.stringify(node.type)); + } +}; + +function getDeclError(node) { + return new Error( + "all declarations should have been transformed into " + + "assignments before the Exploder began its work: " + + JSON.stringify(node)); +} + +Ep.explodeStatement = function(path, labelId) { + const t = util.getTypes(); + let stmt = path.node; + let self = this; + let before, after, head; + + t.assertStatement(stmt); + + if (labelId) { + t.assertIdentifier(labelId); + } else { + labelId = null; + } + + // Explode BlockStatement nodes even if they do not contain a yield, + // because we don't want or need the curly braces. + if (t.isBlockStatement(stmt)) { + path.get("body").forEach(function (path) { + self.explodeStatement(path); + }); + return; + } + + if (!meta.containsLeap(stmt)) { + // Technically we should be able to avoid emitting the statement + // altogether if !meta.hasSideEffects(stmt), but that leads to + // confusing generated code (for instance, `while (true) {}` just + // disappears) and is probably a more appropriate job for a dedicated + // dead code elimination pass. + self.emit(stmt); + return; + } + + switch (stmt.type) { + case "ExpressionStatement": + self.explodeExpression(path.get("expression"), true); + break; + + case "LabeledStatement": + after = loc(); + + // Did you know you can break from any labeled block statement or + // control structure? Well, you can! Note: when a labeled loop is + // encountered, the leap.LabeledEntry created here will immediately + // enclose a leap.LoopEntry on the leap manager's stack, and both + // entries will have the same label. Though this works just fine, it + // may seem a bit redundant. In theory, we could check here to + // determine if stmt knows how to handle its own label; for example, + // stmt happens to be a WhileStatement and so we know it's going to + // establish its own LoopEntry when we explode it (below). Then this + // LabeledEntry would be unnecessary. Alternatively, we might be + // tempted not to pass stmt.label down into self.explodeStatement, + // because we've handled the label here, but that's a mistake because + // labeled loops may contain labeled continue statements, which is not + // something we can handle in this generic case. All in all, I think a + // little redundancy greatly simplifies the logic of this case, since + // it's clear that we handle all possible LabeledStatements correctly + // here, regardless of whether they interact with the leap manager + // themselves. Also remember that labels and break/continue-to-label + // statements are rare, and all of this logic happens at transform + // time, so it has no additional runtime cost. + self.leapManager.withEntry( + new leap.LabeledEntry(after, stmt.label), + function() { + self.explodeStatement(path.get("body"), stmt.label); + } + ); + + self.mark(after); + + break; + + case "WhileStatement": + before = loc(); + after = loc(); + + self.mark(before); + self.jumpIfNot(self.explodeExpression(path.get("test")), after); + self.leapManager.withEntry( + new leap.LoopEntry(after, before, labelId), + function() { self.explodeStatement(path.get("body")); } + ); + self.jump(before); + self.mark(after); + + break; + + case "DoWhileStatement": + let first = loc(); + let test = loc(); + after = loc(); + + self.mark(first); + self.leapManager.withEntry( + new leap.LoopEntry(after, test, labelId), + function() { self.explode(path.get("body")); } + ); + self.mark(test); + self.jumpIf(self.explodeExpression(path.get("test")), first); + self.mark(after); + + break; + + case "ForStatement": + head = loc(); + let update = loc(); + after = loc(); + + if (stmt.init) { + // We pass true here to indicate that if stmt.init is an expression + // then we do not care about its result. + self.explode(path.get("init"), true); + } + + self.mark(head); + + if (stmt.test) { + self.jumpIfNot(self.explodeExpression(path.get("test")), after); + } else { + // No test means continue unconditionally. + } + + self.leapManager.withEntry( + new leap.LoopEntry(after, update, labelId), + function() { self.explodeStatement(path.get("body")); } + ); + + self.mark(update); + + if (stmt.update) { + // We pass true here to indicate that if stmt.update is an + // expression then we do not care about its result. + self.explode(path.get("update"), true); + } + + self.jump(head); + + self.mark(after); + + break; + + case "TypeCastExpression": + return self.explodeExpression(path.get("expression")); + + case "ForInStatement": + head = loc(); + after = loc(); + + let keyIterNextFn = self.makeTempVar(); + self.emitAssign( + keyIterNextFn, + t.callExpression( + util.runtimeProperty("keys"), + [self.explodeExpression(path.get("right"))] + ) + ); + + self.mark(head); + + let keyInfoTmpVar = self.makeTempVar(); + self.jumpIf( + t.memberExpression( + t.assignmentExpression( + "=", + keyInfoTmpVar, + t.callExpression(keyIterNextFn, []) + ), + t.identifier("done"), + false + ), + after + ); + + self.emitAssign( + stmt.left, + t.memberExpression( + keyInfoTmpVar, + t.identifier("value"), + false + ) + ); + + self.leapManager.withEntry( + new leap.LoopEntry(after, head, labelId), + function() { self.explodeStatement(path.get("body")); } + ); + + self.jump(head); + + self.mark(after); + + break; + + case "BreakStatement": + self.emitAbruptCompletion({ + type: "break", + target: self.leapManager.getBreakLoc(stmt.label) + }); + + break; + + case "ContinueStatement": + self.emitAbruptCompletion({ + type: "continue", + target: self.leapManager.getContinueLoc(stmt.label) + }); + + break; + + case "SwitchStatement": + // Always save the discriminant into a temporary variable in case the + // test expressions overwrite values like context.sent. + let disc = self.emitAssign( + self.makeTempVar(), + self.explodeExpression(path.get("discriminant")) + ); + + after = loc(); + let defaultLoc = loc(); + let condition = defaultLoc; + let caseLocs = []; + + // If there are no cases, .cases might be undefined. + let cases = stmt.cases || []; + + for (let i = cases.length - 1; i >= 0; --i) { + let c = cases[i]; + t.assertSwitchCase(c); + + if (c.test) { + condition = t.conditionalExpression( + t.binaryExpression("===", disc, c.test), + caseLocs[i] = loc(), + condition + ); + } else { + caseLocs[i] = defaultLoc; + } + } + + let discriminant = path.get("discriminant"); + util.replaceWithOrRemove(discriminant, condition); + self.jump(self.explodeExpression(discriminant)); + + self.leapManager.withEntry( + new leap.SwitchEntry(after), + function() { + path.get("cases").forEach(function(casePath) { + let i = casePath.key; + self.mark(caseLocs[i]); + + casePath.get("consequent").forEach(function (path) { + self.explodeStatement(path); + }); + }); + } + ); + + self.mark(after); + if (defaultLoc.value === -1) { + self.mark(defaultLoc); + assert.strictEqual(after.value, defaultLoc.value); + } + + break; + + case "IfStatement": + let elseLoc = stmt.alternate && loc(); + after = loc(); + + self.jumpIfNot( + self.explodeExpression(path.get("test")), + elseLoc || after + ); + + self.explodeStatement(path.get("consequent")); + + if (elseLoc) { + self.jump(after); + self.mark(elseLoc); + self.explodeStatement(path.get("alternate")); + } + + self.mark(after); + + break; + + case "ReturnStatement": + self.emitAbruptCompletion({ + type: "return", + value: self.explodeExpression(path.get("argument")) + }); + + break; + + case "WithStatement": + throw new Error("WithStatement not supported in generator functions."); + + case "TryStatement": + after = loc(); + + let handler = stmt.handler; + + let catchLoc = handler && loc(); + let catchEntry = catchLoc && new leap.CatchEntry( + catchLoc, + handler.param + ); + + let finallyLoc = stmt.finalizer && loc(); + let finallyEntry = finallyLoc && + new leap.FinallyEntry(finallyLoc, after); + + let tryEntry = new leap.TryEntry( + self.getUnmarkedCurrentLoc(), + catchEntry, + finallyEntry + ); + + self.tryEntries.push(tryEntry); + self.updateContextPrevLoc(tryEntry.firstLoc); + + self.leapManager.withEntry(tryEntry, function() { + self.explodeStatement(path.get("block")); + + if (catchLoc) { + if (finallyLoc) { + // If we have both a catch block and a finally block, then + // because we emit the catch block first, we need to jump over + // it to the finally block. + self.jump(finallyLoc); + + } else { + // If there is no finally block, then we need to jump over the + // catch block to the fall-through location. + self.jump(after); + } + + self.updateContextPrevLoc(self.mark(catchLoc)); + + let bodyPath = path.get("handler.body"); + let safeParam = self.makeTempVar(); + self.clearPendingException(tryEntry.firstLoc, safeParam); + + bodyPath.traverse(catchParamVisitor, { + safeParam: safeParam, + catchParamName: handler.param.name + }); + + self.leapManager.withEntry(catchEntry, function() { + self.explodeStatement(bodyPath); + }); + } + + if (finallyLoc) { + self.updateContextPrevLoc(self.mark(finallyLoc)); + + self.leapManager.withEntry(finallyEntry, function() { + self.explodeStatement(path.get("finalizer")); + }); + + self.emit(t.returnStatement(t.callExpression( + self.contextProperty("finish"), + [finallyEntry.firstLoc] + ))); + } + }); + + self.mark(after); + + break; + + case "ThrowStatement": + self.emit(t.throwStatement( + self.explodeExpression(path.get("argument")) + )); + + break; + + default: + throw new Error( + "unknown Statement of type " + + JSON.stringify(stmt.type)); + } +}; + +let catchParamVisitor = { + Identifier: function(path, state) { + if (path.node.name === state.catchParamName && util.isReference(path)) { + util.replaceWithOrRemove(path, state.safeParam); + } + }, + + Scope: function(path, state) { + if (path.scope.hasOwnBinding(state.catchParamName)) { + // Don't descend into nested scopes that shadow the catch + // parameter with their own declarations. + path.skip(); + } + } +}; + +Ep.emitAbruptCompletion = function(record) { + if (!isValidCompletion(record)) { + assert.ok( + false, + "invalid completion record: " + + JSON.stringify(record) + ); + } + + assert.notStrictEqual( + record.type, "normal", + "normal completions are not abrupt" + ); + + const t = util.getTypes(); + let abruptArgs = [t.stringLiteral(record.type)]; + + if (record.type === "break" || + record.type === "continue") { + t.assertLiteral(record.target); + abruptArgs[1] = record.target; + } else if (record.type === "return" || + record.type === "throw") { + if (record.value) { + t.assertExpression(record.value); + abruptArgs[1] = record.value; + } + } + + this.emit( + t.returnStatement( + t.callExpression( + this.contextProperty("abrupt"), + abruptArgs + ) + ) + ); +}; + +function isValidCompletion(record) { + let type = record.type; + + if (type === "normal") { + return !hasOwn.call(record, "target"); + } + + if (type === "break" || + type === "continue") { + return !hasOwn.call(record, "value") + && util.getTypes().isLiteral(record.target); + } + + if (type === "return" || + type === "throw") { + return hasOwn.call(record, "value") + && !hasOwn.call(record, "target"); + } + + return false; +} + + +// Not all offsets into emitter.listing are potential jump targets. For +// example, execution typically falls into the beginning of a try block +// without jumping directly there. This method returns the current offset +// without marking it, so that a switch case will not necessarily be +// generated for this offset (I say "not necessarily" because the same +// location might end up being marked in the process of emitting other +// statements). There's no logical harm in marking such locations as jump +// targets, but minimizing the number of switch cases keeps the generated +// code shorter. +Ep.getUnmarkedCurrentLoc = function() { + return util.getTypes().numericLiteral(this.listing.length); +}; + +// The context.prev property takes the value of context.next whenever we +// evaluate the switch statement discriminant, which is generally good +// enough for tracking the last location we jumped to, but sometimes +// context.prev needs to be more precise, such as when we fall +// successfully out of a try block and into a finally block without +// jumping. This method exists to update context.prev to the freshest +// available location. If we were implementing a full interpreter, we +// would know the location of the current instruction with complete +// precision at all times, but we don't have that luxury here, as it would +// be costly and verbose to set context.prev before every statement. +Ep.updateContextPrevLoc = function(loc) { + if (loc) { + util.getTypes().assertLiteral(loc); + + if (loc.value === -1) { + // If an uninitialized location literal was passed in, set its value + // to the current this.listing.length. + loc.value = this.listing.length; + } else { + // Otherwise assert that the location matches the current offset. + assert.strictEqual(loc.value, this.listing.length); + } + + } else { + loc = this.getUnmarkedCurrentLoc(); + } + + // Make sure context.prev is up to date in case we fell into this try + // statement without jumping to it. TODO Consider avoiding this + // assignment when we know control must have jumped here. + this.emitAssign(this.contextProperty("prev"), loc); +}; + +Ep.explodeExpression = function(path, ignoreResult) { + const t = util.getTypes(); + let expr = path.node; + if (expr) { + t.assertExpression(expr); + } else { + return expr; + } + + let self = this; + let result; // Used optionally by several cases below. + let after; + + function finish(expr) { + t.assertExpression(expr); + if (ignoreResult) { + self.emit(expr); + } else { + return expr; + } + } + + // If the expression does not contain a leap, then we either emit the + // expression as a standalone statement or return it whole. + if (!meta.containsLeap(expr)) { + return finish(expr); + } + + // If any child contains a leap (such as a yield or labeled continue or + // break statement), then any sibling subexpressions will almost + // certainly have to be exploded in order to maintain the order of their + // side effects relative to the leaping child(ren). + let hasLeapingChildren = meta.containsLeap.onlyChildren(expr); + + // In order to save the rest of explodeExpression from a combinatorial + // trainwreck of special cases, explodeViaTempVar is responsible for + // deciding when a subexpression needs to be "exploded," which is my + // very technical term for emitting the subexpression as an assignment + // to a temporary variable and the substituting the temporary variable + // for the original subexpression. Think of exploded view diagrams, not + // Michael Bay movies. The point of exploding subexpressions is to + // control the precise order in which the generated code realizes the + // side effects of those subexpressions. + function explodeViaTempVar(tempVar, childPath, ignoreChildResult) { + assert.ok( + !ignoreChildResult || !tempVar, + "Ignoring the result of a child expression but forcing it to " + + "be assigned to a temporary variable?" + ); + + let result = self.explodeExpression(childPath, ignoreChildResult); + + if (ignoreChildResult) { + // Side effects already emitted above. + + } else if (tempVar || (hasLeapingChildren && + !t.isLiteral(result))) { + // If tempVar was provided, then the result will always be assigned + // to it, even if the result does not otherwise need to be assigned + // to a temporary variable. When no tempVar is provided, we have + // the flexibility to decide whether a temporary variable is really + // necessary. Unfortunately, in general, a temporary variable is + // required whenever any child contains a yield expression, since it + // is difficult to prove (at all, let alone efficiently) whether + // this result would evaluate to the same value before and after the + // yield (see #206). One narrow case where we can prove it doesn't + // matter (and thus we do not need a temporary variable) is when the + // result in question is a Literal value. + result = self.emitAssign( + tempVar || self.makeTempVar(), + result + ); + } + return result; + } + + // If ignoreResult is true, then we must take full responsibility for + // emitting the expression with all its side effects, and we should not + // return a result. + + switch (expr.type) { + case "MemberExpression": + return finish(t.memberExpression( + self.explodeExpression(path.get("object")), + expr.computed + ? explodeViaTempVar(null, path.get("property")) + : expr.property, + expr.computed + )); + + case "CallExpression": + let calleePath = path.get("callee"); + let argsPath = path.get("arguments"); + + let newCallee; + let newArgs = []; + + let hasLeapingArgs = false; + argsPath.forEach(function(argPath) { + hasLeapingArgs = hasLeapingArgs || + meta.containsLeap(argPath.node); + }); + + if (t.isMemberExpression(calleePath.node)) { + if (hasLeapingArgs) { + // If the arguments of the CallExpression contained any yield + // expressions, then we need to be sure to evaluate the callee + // before evaluating the arguments, but if the callee was a member + // expression, then we must be careful that the object of the + // member expression still gets bound to `this` for the call. + + let newObject = explodeViaTempVar( + // Assign the exploded callee.object expression to a temporary + // variable so that we can use it twice without reevaluating it. + self.makeTempVar(), + calleePath.get("object") + ); + + let newProperty = calleePath.node.computed + ? explodeViaTempVar(null, calleePath.get("property")) + : calleePath.node.property; + + newArgs.unshift(newObject); + + newCallee = t.memberExpression( + t.memberExpression( + newObject, + newProperty, + calleePath.node.computed + ), + t.identifier("call"), + false + ); + + } else { + newCallee = self.explodeExpression(calleePath); + } + + } else { + newCallee = explodeViaTempVar(null, calleePath); + + if (t.isMemberExpression(newCallee)) { + // If the callee was not previously a MemberExpression, then the + // CallExpression was "unqualified," meaning its `this` object + // should be the global object. If the exploded expression has + // become a MemberExpression (e.g. a context property, probably a + // temporary variable), then we need to force it to be unqualified + // by using the (0, object.property)(...) trick; otherwise, it + // will receive the object of the MemberExpression as its `this` + // object. + newCallee = t.sequenceExpression([ + t.numericLiteral(0), + newCallee + ]); + } + } + + argsPath.forEach(function(argPath) { + newArgs.push(explodeViaTempVar(null, argPath)); + }); + + return finish(t.callExpression( + newCallee, + newArgs + )); + + case "NewExpression": + return finish(t.newExpression( + explodeViaTempVar(null, path.get("callee")), + path.get("arguments").map(function(argPath) { + return explodeViaTempVar(null, argPath); + }) + )); + + case "ObjectExpression": + return finish(t.objectExpression( + path.get("properties").map(function(propPath) { + if (propPath.isObjectProperty()) { + return t.objectProperty( + propPath.node.key, + explodeViaTempVar(null, propPath.get("value")), + propPath.node.computed + ); + } else { + return propPath.node; + } + }) + )); + + case "ArrayExpression": + return finish(t.arrayExpression( + path.get("elements").map(function(elemPath) { + return explodeViaTempVar(null, elemPath); + }) + )); + + case "SequenceExpression": + let lastIndex = expr.expressions.length - 1; + + path.get("expressions").forEach(function(exprPath) { + if (exprPath.key === lastIndex) { + result = self.explodeExpression(exprPath, ignoreResult); + } else { + self.explodeExpression(exprPath, true); + } + }); + + return result; + + case "LogicalExpression": + after = loc(); + + if (!ignoreResult) { + result = self.makeTempVar(); + } + + let left = explodeViaTempVar(result, path.get("left")); + + if (expr.operator === "&&") { + self.jumpIfNot(left, after); + } else { + assert.strictEqual(expr.operator, "||"); + self.jumpIf(left, after); + } + + explodeViaTempVar(result, path.get("right"), ignoreResult); + + self.mark(after); + + return result; + + case "ConditionalExpression": + let elseLoc = loc(); + after = loc(); + let test = self.explodeExpression(path.get("test")); + + self.jumpIfNot(test, elseLoc); + + if (!ignoreResult) { + result = self.makeTempVar(); + } + + explodeViaTempVar(result, path.get("consequent"), ignoreResult); + self.jump(after); + + self.mark(elseLoc); + explodeViaTempVar(result, path.get("alternate"), ignoreResult); + + self.mark(after); + + return result; + + case "UnaryExpression": + return finish(t.unaryExpression( + expr.operator, + // Can't (and don't need to) break up the syntax of the argument. + // Think about delete a[b]. + self.explodeExpression(path.get("argument")), + !!expr.prefix + )); + + case "BinaryExpression": + return finish(t.binaryExpression( + expr.operator, + explodeViaTempVar(null, path.get("left")), + explodeViaTempVar(null, path.get("right")) + )); + + case "AssignmentExpression": + return finish(t.assignmentExpression( + expr.operator, + self.explodeExpression(path.get("left")), + self.explodeExpression(path.get("right")) + )); + + case "UpdateExpression": + return finish(t.updateExpression( + expr.operator, + self.explodeExpression(path.get("argument")), + expr.prefix + )); + + case "YieldExpression": + after = loc(); + let arg = expr.argument && self.explodeExpression(path.get("argument")); + + if (arg && expr.delegate) { + let result = self.makeTempVar(); + + let ret = t.returnStatement(t.callExpression( + self.contextProperty("delegateYield"), + [ + arg, + t.stringLiteral(result.property.name), + after + ] + )); + ret.loc = expr.loc; + + self.emit(ret); + self.mark(after); + + return result; + } + + self.emitAssign(self.contextProperty("next"), after); + + let ret = t.returnStatement(arg || null); + // Preserve the `yield` location so that source mappings for the statements + // link back to the yield properly. + ret.loc = expr.loc; + self.emit(ret); + self.mark(after); + + return self.contextProperty("sent"); + + default: + throw new Error( + "unknown Expression of type " + + JSON.stringify(expr.type)); + } +}; -- cgit v1.2.3