996 lines
33 KiB
JavaScript
996 lines
33 KiB
JavaScript
"use strict";
|
|
|
|
var _stringify = require("babel-runtime/core-js/json/stringify");
|
|
|
|
var _stringify2 = _interopRequireDefault(_stringify);
|
|
|
|
var _assert = require("assert");
|
|
|
|
var _assert2 = _interopRequireDefault(_assert);
|
|
|
|
var _babelTypes = require("babel-types");
|
|
|
|
var t = _interopRequireWildcard(_babelTypes);
|
|
|
|
var _leap = require("./leap");
|
|
|
|
var leap = _interopRequireWildcard(_leap);
|
|
|
|
var _meta = require("./meta");
|
|
|
|
var meta = _interopRequireWildcard(_meta);
|
|
|
|
var _util = require("./util");
|
|
|
|
var util = _interopRequireWildcard(_util);
|
|
|
|
function _interopRequireWildcard(obj) { if (obj && obj.__esModule) { return obj; } else { var newObj = {}; if (obj != null) { for (var key in obj) { if (Object.prototype.hasOwnProperty.call(obj, key)) newObj[key] = obj[key]; } } newObj.default = obj; return newObj; } }
|
|
|
|
function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
|
|
|
|
var hasOwn = Object.prototype.hasOwnProperty; /**
|
|
* Copyright (c) 2014, Facebook, Inc.
|
|
* All rights reserved.
|
|
*
|
|
* This source code is licensed under the BSD-style license found in the
|
|
* https://raw.github.com/facebook/regenerator/master/LICENSE file. An
|
|
* additional grant of patent rights can be found in the PATENTS file in
|
|
* the same directory.
|
|
*/
|
|
|
|
function Emitter(contextId) {
|
|
_assert2.default.ok(this instanceof Emitter);
|
|
t.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);
|
|
}
|
|
|
|
var 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 t.numericLiteral(-1);
|
|
}
|
|
|
|
// Sets the exact value of the given location to the offset of the next
|
|
// Statement emitted.
|
|
Ep.mark = function (loc) {
|
|
t.assertLiteral(loc);
|
|
var 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.
|
|
_assert2.default.strictEqual(loc.value, index);
|
|
}
|
|
this.marked[index] = true;
|
|
return loc;
|
|
};
|
|
|
|
Ep.emit = function (node) {
|
|
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) {
|
|
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) {
|
|
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) {
|
|
t.assertExpression(valuePath.value);
|
|
|
|
this.emitAssign(this.contextProperty("rval"), this.explodeExpression(valuePath));
|
|
};
|
|
|
|
Ep.clearPendingException = function (tryLoc, assignee) {
|
|
t.assertLiteral(tryLoc);
|
|
|
|
var 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(t.breakStatement());
|
|
};
|
|
|
|
// Conditional jump.
|
|
Ep.jumpIf = function (test, toLoc) {
|
|
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) {
|
|
t.assertExpression(test);
|
|
t.assertLiteral(toLoc);
|
|
|
|
var negatedTest = void 0;
|
|
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) {
|
|
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 () {
|
|
var self = this;
|
|
var cases = [];
|
|
var current = void 0;
|
|
|
|
// 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.
|
|
var 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;
|
|
}
|
|
|
|
var lastLocValue = 0;
|
|
|
|
return t.arrayExpression(this.tryEntries.map(function (tryEntry) {
|
|
var thisLocValue = tryEntry.firstLoc.value;
|
|
_assert2.default.ok(thisLocValue >= lastLocValue, "try entries out of order");
|
|
lastLocValue = thisLocValue;
|
|
|
|
var ce = tryEntry.catchEntry;
|
|
var fe = tryEntry.finallyEntry;
|
|
|
|
var 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) {
|
|
var node = path.node;
|
|
var 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 " + (0, _stringify2.default)(node.type));
|
|
}
|
|
};
|
|
|
|
function getDeclError(node) {
|
|
return new Error("all declarations should have been transformed into " + "assignments before the Exploder began its work: " + (0, _stringify2.default)(node));
|
|
}
|
|
|
|
Ep.explodeStatement = function (path, labelId) {
|
|
var stmt = path.node;
|
|
var self = this;
|
|
var before = void 0,
|
|
after = void 0,
|
|
head = void 0;
|
|
|
|
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":
|
|
var first = loc();
|
|
var 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();
|
|
var 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();
|
|
|
|
var keyIterNextFn = self.makeTempVar();
|
|
self.emitAssign(keyIterNextFn, t.callExpression(util.runtimeProperty("keys"), [self.explodeExpression(path.get("right"))]));
|
|
|
|
self.mark(head);
|
|
|
|
var 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.
|
|
var disc = self.emitAssign(self.makeTempVar(), self.explodeExpression(path.get("discriminant")));
|
|
|
|
after = loc();
|
|
var defaultLoc = loc();
|
|
var condition = defaultLoc;
|
|
var caseLocs = [];
|
|
|
|
// If there are no cases, .cases might be undefined.
|
|
var cases = stmt.cases || [];
|
|
|
|
for (var i = cases.length - 1; i >= 0; --i) {
|
|
var 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;
|
|
}
|
|
}
|
|
|
|
var 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) {
|
|
var 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);
|
|
_assert2.default.strictEqual(after.value, defaultLoc.value);
|
|
}
|
|
|
|
break;
|
|
|
|
case "IfStatement":
|
|
var 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();
|
|
|
|
var handler = stmt.handler;
|
|
|
|
var catchLoc = handler && loc();
|
|
var catchEntry = catchLoc && new leap.CatchEntry(catchLoc, handler.param);
|
|
|
|
var finallyLoc = stmt.finalizer && loc();
|
|
var finallyEntry = finallyLoc && new leap.FinallyEntry(finallyLoc, after);
|
|
|
|
var 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));
|
|
|
|
var bodyPath = path.get("handler.body");
|
|
var 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 " + (0, _stringify2.default)(stmt.type));
|
|
}
|
|
};
|
|
|
|
var catchParamVisitor = {
|
|
Identifier: function Identifier(path, state) {
|
|
if (path.node.name === state.catchParamName && util.isReference(path)) {
|
|
util.replaceWithOrRemove(path, state.safeParam);
|
|
}
|
|
},
|
|
|
|
Scope: function Scope(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)) {
|
|
_assert2.default.ok(false, "invalid completion record: " + (0, _stringify2.default)(record));
|
|
}
|
|
|
|
_assert2.default.notStrictEqual(record.type, "normal", "normal completions are not abrupt");
|
|
|
|
var 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) {
|
|
var type = record.type;
|
|
|
|
if (type === "normal") {
|
|
return !hasOwn.call(record, "target");
|
|
}
|
|
|
|
if (type === "break" || type === "continue") {
|
|
return !hasOwn.call(record, "value") && t.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 t.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) {
|
|
t.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.
|
|
_assert2.default.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) {
|
|
var expr = path.node;
|
|
if (expr) {
|
|
t.assertExpression(expr);
|
|
} else {
|
|
return expr;
|
|
}
|
|
|
|
var self = this;
|
|
var result = void 0; // Used optionally by several cases below.
|
|
var after = void 0;
|
|
|
|
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).
|
|
var 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) {
|
|
_assert2.default.ok(!ignoreChildResult || !tempVar, "Ignoring the result of a child expression but forcing it to " + "be assigned to a temporary variable?");
|
|
|
|
var 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":
|
|
var calleePath = path.get("callee");
|
|
var argsPath = path.get("arguments");
|
|
|
|
var newCallee = void 0;
|
|
var newArgs = [];
|
|
|
|
var 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.
|
|
|
|
var 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"));
|
|
|
|
var 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":
|
|
var 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();
|
|
}
|
|
|
|
var left = explodeViaTempVar(result, path.get("left"));
|
|
|
|
if (expr.operator === "&&") {
|
|
self.jumpIfNot(left, after);
|
|
} else {
|
|
_assert2.default.strictEqual(expr.operator, "||");
|
|
self.jumpIf(left, after);
|
|
}
|
|
|
|
explodeViaTempVar(result, path.get("right"), ignoreResult);
|
|
|
|
self.mark(after);
|
|
|
|
return result;
|
|
|
|
case "ConditionalExpression":
|
|
var elseLoc = loc();
|
|
after = loc();
|
|
var 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();
|
|
var arg = expr.argument && self.explodeExpression(path.get("argument"));
|
|
|
|
if (arg && expr.delegate) {
|
|
var _result = self.makeTempVar();
|
|
|
|
self.emit(t.returnStatement(t.callExpression(self.contextProperty("delegateYield"), [arg, t.stringLiteral(_result.property.name), after])));
|
|
|
|
self.mark(after);
|
|
|
|
return _result;
|
|
}
|
|
|
|
self.emitAssign(self.contextProperty("next"), after);
|
|
self.emit(t.returnStatement(arg || null));
|
|
self.mark(after);
|
|
|
|
return self.contextProperty("sent");
|
|
|
|
default:
|
|
throw new Error("unknown Expression of type " + (0, _stringify2.default)(expr.type));
|
|
}
|
|
}; |