// Main type inference engine
// Walks an AST, building up a graph of abstract values and constraints
// that cause types to flow from one node to another. Also defines a
// number of utilities for accessing ASTs and scopes.
// Analysis is done in a context, which is tracked by the dynamically
// bound cx variable. Use withContext to set the current context.
// For memory-saving reasons, individual types export an interface
// similar to abstract values (which can hold multiple types), and can
// thus be used in place abstract values that only ever contain a
// single type.
(function(root, mod) {
if (typeof exports == "object" && typeof module == "object") // CommonJS
return mod(exports, require("acorn/acorn"), require("acorn/acorn_loose"), require("acorn/walk"),
require("./def"), require("./signal"));
if (typeof define == "function" && define.amd) // AMD
return define(["exports", "acorn/acorn", "acorn/acorn_loose", "acorn/walk", "./def", "./signal"], mod);
mod(root.tern || (root.tern = {}), acorn, acorn, acorn.walk, tern.def, tern.signal); // Plain browser env
})(this, function(exports, acorn, acorn_loose, walk, def, signal) {
"use strict";
var toString = exports.toString = function(type, maxDepth, parent) {
if (!type || type == parent || maxDepth && maxDepth < -3) return "?";
return type.toString(maxDepth, parent);
};
// A variant of AVal used for unknown, dead-end values. Also serves
// as prototype for AVals, Types, and Constraints because it
// implements 'empty' versions of all the methods that the code
// expects.
var ANull = exports.ANull = signal.mixin({
addType: function() {},
propagate: function() {},
getProp: function() { return ANull; },
forAllProps: function() {},
hasType: function() { return false; },
isEmpty: function() { return true; },
getFunctionType: function() {},
getObjType: function() {},
getSymbolType: function() {},
getType: function() {},
gatherProperties: function() {},
propagatesTo: function() {},
typeHint: function() {},
propHint: function() {},
toString: function() { return "?"; }
});
function extend(proto, props) {
var obj = Object.create(proto);
if (props) for (var prop in props) obj[prop] = props[prop];
return obj;
}
// ABSTRACT VALUES
var WG_DEFAULT = 100, WG_NEW_INSTANCE = 90, WG_MADEUP_PROTO = 10,
WG_MULTI_MEMBER = 6, WG_CATCH_ERROR = 6,
WG_PHANTOM_OBJ = 1,
WG_GLOBAL_THIS = 90, WG_SPECULATIVE_THIS = 2, WG_SPECULATIVE_PROTO_THIS = 4;
var AVal = exports.AVal = function() {
this.types = [];
this.forward = null;
this.maxWeight = 0;
};
AVal.prototype = extend(ANull, {
addType: function(type, weight) {
weight = weight || WG_DEFAULT;
if (this.maxWeight < weight) {
this.maxWeight = weight;
if (this.types.length == 1 && this.types[0] == type) return;
this.types.length = 0;
} else if (this.maxWeight > weight || this.types.indexOf(type) > -1) {
return;
}
this.signal("addType", type);
this.types.push(type);
var forward = this.forward;
if (forward) withWorklist(function(add) {
for (var i = 0; i < forward.length; ++i) add(type, forward[i], weight);
});
},
propagate: function(target, weight) {
if (target == ANull || (target instanceof Type && this.forward && this.forward.length > 2)) return;
if (weight && weight != WG_DEFAULT) target = new Muffle(target, weight);
(this.forward || (this.forward = [])).push(target);
var types = this.types;
if (types.length) withWorklist(function(add) {
for (var i = 0; i < types.length; ++i) add(types[i], target, weight);
});
},
getProp: function(prop) {
if (prop == "__proto__" || prop == "✖") return ANull;
var found = (this.props || (this.props = Object.create(null)))[prop];
if (!found) {
found = this.props[prop] = new AVal;
this.propagate(new GetProp(prop, found));
}
return found;
},
forAllProps: function(c) {
this.propagate(new ForAllProps(c));
},
hasType: function(type) {
return this.types.indexOf(type) > -1;
},
isEmpty: function() { return this.types.length === 0; },
getFunctionType: function() {
for (var i = this.types.length - 1; i >= 0; --i)
if (this.types[i] instanceof Fn) return this.types[i];
},
getObjType: function() {
var seen = null;
for (var i = this.types.length - 1; i >= 0; --i) {
var type = this.types[i];
if (!(type instanceof Obj)) continue;
if (type.name) return type;
if (!seen) seen = type;
}
return seen;
},
getSymbolType: function() {
for (var i = this.types.length - 1; i >= 0; --i)
if (this.types[i] instanceof Sym) return this.types[i]
},
getType: function(guess) {
if (this.types.length === 0 && guess !== false) return this.makeupType();
if (this.types.length === 1) return this.types[0];
return canonicalType(this.types);
},
toString: function(maxDepth, parent) {
if (this.types.length == 0) return toString(this.makeupType(), maxDepth, parent);
if (this.types.length == 1) return toString(this.types[0], maxDepth, parent);
var simplified = simplifyTypes(this.types);
if (simplified.length > 2) return "?";
return simplified.map(function(tp) { return toString(tp, maxDepth, parent); }).join("|");
},
makeupPropType: function(obj) {
var propName = this.propertyName;
var protoProp = obj.proto && obj.proto.hasProp(propName);
if (protoProp) {
var fromProto = protoProp.getType();
if (fromProto) return fromProto;
}
if (propName != "<i>") {
var computedProp = obj.hasProp("<i>");
if (computedProp) return computedProp.getType();
} else if (obj.props["<i>"] != this) {
for (var prop in obj.props) {
var val = obj.props[prop];
if (!val.isEmpty()) return val.getType();
}
}
},
makeupType: function() {
var computed = this.propertyOf && this.makeupPropType(this.propertyOf);
if (computed) return computed;
if (!this.forward) return null;
for (var i = this.forward.length - 1; i >= 0; --i) {
var hint = this.forward[i].typeHint();
if (hint && !hint.isEmpty()) {guessing = true; return hint;}
}
var props = Object.create(null), foundProp = null;
for (var i = 0; i < this.forward.length; ++i) {
var prop = this.forward[i].propHint();
if (prop && prop != "length" && prop != "<i>" && prop != "✖" && prop != cx.completingProperty) {
props[prop] = true;
foundProp = prop;
}
}
if (!foundProp) return null;
var objs = objsWithProp(foundProp);
if (objs) {
var matches = [];
search: for (var i = 0; i < objs.length; ++i) {
var obj = objs[i];
for (var prop in props) if (!obj.hasProp(prop)) continue search;
if (obj.hasCtor) obj = getInstance(obj);
matches.push(obj);
}
var canon = canonicalType(matches);
if (canon) {guessing = true; return canon;}
}
},
typeHint: function() { return this.types.length ? this.getType() : null; },
propagatesTo: function() { return this; },
gatherProperties: function(f, depth) {
for (var i = 0; i < this.types.length; ++i)
this.types[i].gatherProperties(f, depth);
},
guessProperties: function(f) {
if (this.forward) for (var i = 0; i < this.forward.length; ++i) {
var prop = this.forward[i].propHint();
if (prop) f(prop, null, 0);
}
var guessed = this.makeupType();
if (guessed) guessed.gatherProperties(f);
}
});
function similarAVal(a, b, depth) {
var typeA = a.getType(false), typeB = b.getType(false);
if (!typeA || !typeB) return true;
return similarType(typeA, typeB, depth);
}
function similarType(a, b, depth) {
if (!a || depth >= 5) return b;
if (!a || a == b) return a;
if (!b) return a;
if (a.constructor != b.constructor) return false;
if (a.constructor == Arr) {
var innerA = a.getProp("<i>").getType(false);
if (!innerA) return b;
var innerB = b.getProp("<i>").getType(false);
if (!innerB || similarType(innerA, innerB, depth + 1)) return b;
} else if (a.constructor == Obj) {
var propsA = 0, propsB = 0, same = 0;
for (var prop in a.props) {
propsA++;
if (prop in b.props && similarAVal(a.props[prop], b.props[prop], depth + 1))
same++;
}
for (var prop in b.props) propsB++;
if (propsA && propsB && same < Math.max(propsA, propsB) / 2) return false;
return propsA > propsB ? a : b;
} else if (a.constructor == Fn) {
if (a.args.length != b.args.length ||
!a.args.every(function(tp, i) { return similarAVal(tp, b.args[i], depth + 1); }) ||
!similarAVal(a.retval, b.retval, depth + 1) || !similarAVal(a.self, b.self, depth + 1))
return false;
return a;
} else {
return false;
}
}
var simplifyTypes = exports.simplifyTypes = function(types) {
var found = [];
outer: for (var i = 0; i < types.length; ++i) {
var tp = types[i];
for (var j = 0; j < found.length; j++) {
var similar = similarType(tp, found[j], 0);
if (similar) {
found[j] = similar;
continue outer;
}
}
found.push(tp);
}
return found;
};
function canonicalType(types) {
var arrays = 0, fns = 0, objs = 0, prim = null;
for (var i = 0; i < types.length; ++i) {
var tp = types[i];
if (tp instanceof Arr) ++arrays;
else if (tp instanceof Fn) ++fns;
else if (tp instanceof Obj) ++objs;
else if (tp instanceof Prim) {
if (prim && tp.name != prim.name) return null;
prim = tp;
}
}
var kinds = (arrays && 1) + (fns && 1) + (objs && 1) + (prim && 1);
if (kinds > 1) return null;
if (prim) return prim;
var maxScore = 0, maxTp = null;
for (var i = 0; i < types.length; ++i) {
var tp = types[i], score = 0;
if (arrays) {
score = tp.getProp("<i>").isEmpty() ? 1 : 2;
} else if (fns) {
score = 1;
for (var j = 0; j < tp.args.length; ++j) if (!tp.args[j].isEmpty()) ++score;
if (!tp.retval.isEmpty()) ++score;
} else if (objs) {
score = tp.name ? 100 : 2;
}
if (score >= maxScore) { maxScore = score; maxTp = tp; }
}
return maxTp;
}
// PROPAGATION STRATEGIES
var constraint = exports.constraint = function(methods) {
var ctor = function() {
this.origin = cx.curOrigin;
this.construct.apply(this, arguments);
};
ctor.prototype = Object.create(ANull);
for (var m in methods) if (methods.hasOwnProperty(m)) ctor.prototype[m] = methods[m];
return ctor;
};
var GetProp = constraint({
construct: function(prop, target) {
this.prop = prop; this.target = target;
},
addType: function(type, weight) {
if (type.getProp)
type.getProp(this.prop).propagate(this.target, weight);
},
propHint: function() { return this.prop; },
propagatesTo: function() {
if (this.prop == "<i>" || !/[^\w_]/.test(this.prop))
return {target: this.target, pathExt: "." + this.prop};
}
});
var DefProp = exports.PropHasSubset = exports.DefProp = constraint({
construct: function(prop, type, originNode) {
this.prop = prop; this.type = type; this.originNode = originNode;
},
addType: function(type, weight) {
if (!(type instanceof Obj)) return;
var prop = type.defProp(this.prop, this.originNode);
if (!prop.origin) prop.origin = this.origin;
this.type.propagate(prop, weight);
},
propHint: function() { return this.prop; }
});
var ForAllProps = constraint({
construct: function(c) { this.c = c; },
addType: function(type) {
if (!(type instanceof Obj)) return;
type.forAllProps(this.c);
}
});
function withDisabledComputing(fn, body) {
cx.disabledComputing = {fn: fn, prev: cx.disabledComputing};
var result = body();
cx.disabledComputing = cx.disabledComputing.prev;
return result;
}
var IsCallee = exports.IsCallee = constraint({
construct: function(self, args, argNodes, retval) {
this.self = self; this.args = args; this.argNodes = argNodes; this.retval = retval;
this.disabled = cx.disabledComputing;
},
addType: function(fn, weight) {
if (!(fn instanceof Fn)) return;
for (var i = 0; i < this.args.length; ++i) {
if (i < fn.args.length) this.args[i].propagate(fn.args[i], weight);
if (fn.arguments) this.args[i].propagate(fn.arguments, weight);
}
this.self.propagate(fn.self, this.self == cx.topScope ? WG_GLOBAL_THIS : weight);
var compute = fn.computeRet, result = fn.retval
if (compute) for (var d = this.disabled; d; d = d.prev)
if (d.fn == fn || fn.originNode && d.fn.originNode == fn.originNode) compute = null;
if (compute) {
var old = cx.disabledComputing;
cx.disabledComputing = this.disabled;
result = compute(this.self, this.args, this.argNodes)
cx.disabledComputing = old;
}
maybeIterator(fn, result).propagate(this.retval, weight)
},
typeHint: function() {
var names = [];
for (var i = 0; i < this.args.length; ++i) names.push("?");
return new Fn(null, this.self, this.args, names, ANull);
},
propagatesTo: function() {
return {target: this.retval, pathExt: ".!ret"};
}
});
var HasMethodCall = constraint({
construct: function(propName, args, argNodes, retval) {
this.propName = propName; this.args = args; this.argNodes = argNodes; this.retval = retval;
this.disabled = cx.disabledComputing;
},
addType: function(obj, weight) {
var callee = new IsCallee(obj, this.args, this.argNodes, this.retval);
callee.disabled = this.disabled;
obj.getProp(this.propName).propagate(callee, weight);
},
propHint: function() { return this.propName; }
});
var IsCtor = exports.IsCtor = constraint({
construct: function(target, noReuse) {
this.target = target; this.noReuse = noReuse;
},
addType: function(f, weight) {
if (!(f instanceof Fn)) return;
if (cx.parent && !cx.parent.options.reuseInstances) this.noReuse = true;
f.getProp("prototype").propagate(new IsProto(this.noReuse ? false : f, this.target), weight);
}
});
var getInstance = exports.getInstance = function(obj, ctor) {
if (ctor === false) return new Obj(obj);
if (!ctor) ctor = obj.hasCtor;
if (!obj.instances) obj.instances = [];
for (var i = 0; i < obj.instances.length; ++i) {
var cur = obj.instances[i];
if (cur.ctor == ctor) return cur.instance;
}
var instance = new Obj(obj, ctor && ctor.name);
instance.origin = obj.origin;
obj.instances.push({ctor: ctor, instance: instance});
return instance;
};
var IsProto = exports.IsProto = constraint({
construct: function(ctor, target) {
this.ctor = ctor; this.target = target;
},
addType: function(o, _weight) {
if (!(o instanceof Obj)) return;
if ((this.count = (this.count || 0) + 1) > 8) return;
if (o == cx.protos.Array)
this.target.addType(new Arr);
else
this.target.addType(getInstance(o, this.ctor));
}
});
var FnPrototype = constraint({
construct: function(fn) { this.fn = fn; },
addType: function(o, _weight) {
if (o instanceof Obj && !o.hasCtor) {
o.hasCtor = this.fn;
var adder = new SpeculativeThis(o, this.fn);
adder.addType(this.fn);
o.forAllProps(function(_prop, val, local) {
if (local) val.propagate(adder);
});
}
}
});
var IsAdded = constraint({
construct: function(other, target) {
this.other = other; this.target = target;
},
addType: function(type, weight) {
if (type == cx.str)
this.target.addType(cx.str, weight);
else if (type == cx.num && this.other.hasType(cx.num))
this.target.addType(cx.num, weight);
},
typeHint: function() { return this.other; }
});
var IfObj = exports.IfObj = constraint({
construct: function(target) { this.target = target; },
addType: function(t, weight) {
if (t instanceof Obj) this.target.addType(t, weight);
},
propagatesTo: function() { return this.target; }
});
var SpeculativeThis = constraint({
construct: function(obj, ctor) { this.obj = obj; this.ctor = ctor; },
addType: function(tp) {
if (tp instanceof Fn && tp.self)
tp.self.addType(getInstance(this.obj, this.ctor), WG_SPECULATIVE_PROTO_THIS);
}
});
var HasProto = constraint({
construct: function(obj) { this.obj = obj },
addType: function(tp) {
if (tp instanceof Obj && this.obj.proto == cx.protos.Object)
this.obj.replaceProto(tp)
}
});
var Muffle = constraint({
construct: function(inner, weight) {
this.inner = inner; this.weight = weight;
},
addType: function(tp, weight) {
this.inner.addType(tp, Math.min(weight, this.weight));
},
propagatesTo: function() { return this.inner.propagatesTo(); },
typeHint: function() { return this.inner.typeHint(); },
propHint: function() { return this.inner.propHint(); }
});
// TYPE OBJECTS
var Type = exports.Type = function() {};
Type.prototype = extend(ANull, {
constructor: Type,
propagate: function(c, w) { c.addType(this, w); },
hasType: function(other) { return other == this; },
isEmpty: function() { return false; },
typeHint: function() { return this; },
getType: function() { return this; }
});
var Prim = exports.Prim = function(proto, name) { this.name = name; this.proto = proto; };
Prim.prototype = extend(Type.prototype, {
constructor: Prim,
toString: function() { return this.name; },
getProp: function(prop) {return this.proto.hasProp(prop) || ANull;},
gatherProperties: function(f, depth) {
if (this.proto) this.proto.gatherProperties(f, depth);
}
});
function isInteger(str) {
var c0 = str.charCodeAt(0)
if (c0 >= 48 && c0 <= 57) return !/\D/.test(str)
else return false
}
var Obj = exports.Obj = function(proto, name) {
if (!this.props) this.props = Object.create(null);
this.proto = proto === true ? cx.protos.Object : proto;
if (proto && !name && proto.name && !(this instanceof Fn)) {
var match = /^(.*)\.prototype$/.exec(this.proto.name);
if (match) name = match[1];
}
this.name = name;
this.maybeProps = null;
this.origin = cx.curOrigin;
};
Obj.prototype = extend(Type.prototype, {
constructor: Obj,
toString: function(maxDepth) {
if (maxDepth == null) maxDepth = 0;
if (maxDepth <= 0 && this.name) return this.name;
var props = [], etc = false;
for (var prop in this.props) if (prop != "<i>") {
if (props.length > 5) { etc = true; break; }
if (maxDepth)
props.push(prop + ": " + toString(this.props[prop], maxDepth - 1, this));
else
props.push(prop);
}
props.sort();
if (etc) props.push("...");
return "{" + props.join(", ") + "}";
},
hasProp: function(prop, searchProto) {
if (isInteger(prop)) prop = this.normalizeIntegerProp(prop)
var found = this.props[prop];
if (searchProto !== false)
for (var p = this.proto; p && !found; p = p.proto) found = p.props[prop];
return found;
},
defProp: function(prop, originNode) {
var found = this.hasProp(prop, false);
if (found) {
if (originNode && !found.originNode) found.originNode = originNode;
return found;
}
if (prop == "__proto__" || prop == "✖") return ANull;
if (isInteger(prop)) prop = this.normalizeIntegerProp(prop)
var av = this.maybeProps && this.maybeProps[prop];
if (av) {
delete this.maybeProps[prop];
this.maybeUnregProtoPropHandler();
} else {
av = new AVal;
av.propertyOf = this;
av.propertyName = prop;
}
this.props[prop] = av;
av.originNode = originNode;
av.origin = cx.curOrigin;
this.broadcastProp(prop, av, true);
return av;
},
getProp: function(prop) {
var found = this.hasProp(prop, true) || (this.maybeProps && this.maybeProps[prop]);
if (found) return found;
if (prop == "__proto__" || prop == "✖") return ANull;
if (isInteger(prop)) prop = this.normalizeIntegerProp(prop)
var av = this.ensureMaybeProps()[prop] = new AVal;
av.propertyOf = this;
av.propertyName = prop;
return av;
},
normalizeIntegerProp: function(_) { return "<i>" },
broadcastProp: function(prop, val, local) {
if (local) {
this.signal("addProp", prop, val);
// If this is a scope, it shouldn't be registered
if (!(this instanceof Scope)) registerProp(prop, this);
}
if (this.onNewProp) for (var i = 0; i < this.onNewProp.length; ++i) {
var h = this.onNewProp[i];
h.onProtoProp ? h.onProtoProp(prop, val, local) : h(prop, val, local);
}
},
onProtoProp: function(prop, val, _local) {
var maybe = this.maybeProps && this.maybeProps[prop];
if (maybe) {
delete this.maybeProps[prop];
this.maybeUnregProtoPropHandler();
this.proto.getProp(prop).propagate(maybe);
}
this.broadcastProp(prop, val, false);
},
replaceProto: function(proto) {
if (this.proto && this.maybeProps)
this.proto.unregPropHandler(this)
this.proto = proto
if (this.maybeProps)
this.proto.forAllProps(this)
},
ensureMaybeProps: function() {
if (!this.maybeProps) {
if (this.proto) this.proto.forAllProps(this);
this.maybeProps = Object.create(null);
}
return this.maybeProps;
},
removeProp: function(prop) {
var av = this.props[prop];
delete this.props[prop];
this.ensureMaybeProps()[prop] = av;
av.types.length = 0;
},
forAllProps: function(c) {
if (!this.onNewProp) {
this.onNewProp = [];
if (this.proto) this.proto.forAllProps(this);
}
this.onNewProp.push(c);
for (var o = this; o; o = o.proto) for (var prop in o.props) {
if (c.onProtoProp)
c.onProtoProp(prop, o.props[prop], o == this);
else
c(prop, o.props[prop], o == this);
}
},
maybeUnregProtoPropHandler: function() {
if (this.maybeProps) {
for (var _n in this.maybeProps) return;
this.maybeProps = null;
}
if (!this.proto || this.onNewProp && this.onNewProp.length) return;
this.proto.unregPropHandler(this);
},
unregPropHandler: function(handler) {
for (var i = 0; i < this.onNewProp.length; ++i)
if (this.onNewProp[i] == handler) { this.onNewProp.splice(i, 1); break; }
this.maybeUnregProtoPropHandler();
},
gatherProperties: function(f, depth) {
for (var prop in this.props) if (prop != "<i>" && prop.charAt(0) != ":")
f(prop, this, depth);
if (this.proto) this.proto.gatherProperties(f, depth + 1);
},
getObjType: function() { return this; }
});
var Fn = exports.Fn = function(name, self, args, argNames, retval, generator) {
Obj.call(this, cx.protos.Function, name);
this.self = self;
this.args = args;
this.argNames = argNames;
this.retval = retval;
this.generator = generator
};
Fn.prototype = extend(Obj.prototype, {
constructor: Fn,
toString: function(maxDepth) {
if (maxDepth == null) maxDepth = 0;
var str = this.generator ? "fn*(" : "fn(";
for (var i = 0; i < this.args.length; ++i) {
if (i) str += ", ";
var name = this.argNames[i];
if (name && name != "?") str += name + ": ";
str += maxDepth > -3 ? toString(this.args[i], maxDepth - 1, this) : "?";
}
str += ")";
if (!this.retval.isEmpty())
str += " -> " + (maxDepth > -3 ? toString(this.retval, maxDepth - 1, this) : "?");
return str;
},
getProp: function(prop) {
if (prop == "prototype") {
var known = this.hasProp(prop, false);
if (!known) {
known = this.defProp(prop);
var proto = new Obj(true, this.name && this.name + ".prototype");
proto.origin = this.origin;
known.addType(proto, WG_MADEUP_PROTO);
}
return known;
}
return Obj.prototype.getProp.call(this, prop);
},
defProp: function(prop, originNode) {
if (prop == "prototype") {
var found = this.hasProp(prop, false);
if (found) return found;
found = Obj.prototype.defProp.call(this, prop, originNode);
found.origin = this.origin;
found.propagate(new FnPrototype(this));
return found;
}
return Obj.prototype.defProp.call(this, prop, originNode);
},
getFunctionType: function() { return this; }
});
var Arr = exports.Arr = function(contentType) {
Obj.call(this, cx.protos.Array)
var content = this.defProp("<i>")
if (Array.isArray(contentType)) {
this.tuple = contentType.length
for (var i = 0; i < contentType.length; i++) {
var prop = this.defProp(String(i))
contentType[i].propagate(prop)
prop.propagate(content)
}
} else if (contentType) {
this.tuple = 0
contentType.propagate(content)
}
};
Arr.prototype = extend(Obj.prototype, {
constructor: Arr,
toString: function(maxDepth) {
if (maxDepth == null) maxDepth = 0
if (maxDepth <= -3) return "[?]"
var content = ""
if (this.tuple) {
var similar
for (var i = 0; i in this.props; i++) {
var type = toString(this.getProp(String(i)), maxDepth - 1, this)
if (similar == null)
similar = type
else if (similar != type)
similar = false
else
similar = type
content += (content ? ", " : "") + type
}
if (similar) content = similar
} else {
content = toString(this.getProp("<i>"), maxDepth - 1, this)
}
return "[" + content + "]"
},
normalizeIntegerProp: function(prop) {
if (+prop < this.tuple) return prop
else return "<i>"
}
});
var Sym = exports.Sym = function(name, originNode) {
Prim.call(this, cx.protos.Symbol, "Symbol")
this.symName = name
this.originNode = originNode
}
Sym.prototype = extend(Prim.prototype, {
constructor: Sym,
asPropName: function() { return ":" + this.symName },
getSymbolType: function() { return this }
})
exports.getSymbol = function(name, originNode) {
var cleanName = name.replace(/[^\w$\.]/g, "_")
var known = cx.symbols[cleanName]
if (known) {
if (originNode && !known.originNode) known.originNode = originNode
return known
}
return cx.symbols[cleanName] = new Sym(cleanName, originNode)
}
// THE PROPERTY REGISTRY
function registerProp(prop, obj) {
var data = cx.props[prop] || (cx.props[prop] = []);
data.push(obj);
}
function objsWithProp(prop) {
return cx.props[prop];
}
// INFERENCE CONTEXT
exports.Context = function(defs, parent) {
this.parent = parent;
this.props = Object.create(null);
this.protos = Object.create(null);
this.origins = [];
this.curOrigin = "ecma5";
this.paths = Object.create(null);
this.definitions = Object.create(null);
this.purgeGen = 0;
this.workList = null;
this.disabledComputing = null;
this.curSuperCtor = this.curSuper = null;
this.symbols = Object.create(null)
exports.withContext(this, function() {
cx.protos.Object = new Obj(null, "Object.prototype");
cx.topScope = new Scope();
cx.topScope.name = "<top>";
cx.protos.Array = new Obj(true, "Array.prototype");
cx.protos.Function = new Fn("Function.prototype", ANull, [], [], ANull);
cx.protos.Function.proto = cx.protos.Object;
cx.protos.RegExp = new Obj(true, "RegExp.prototype");
cx.protos.String = new Obj(true, "String.prototype");
cx.protos.Number = new Obj(true, "Number.prototype");
cx.protos.Boolean = new Obj(true, "Boolean.prototype");
cx.protos.Symbol = new Obj(true, "Symbol.prototype");
cx.str = new Prim(cx.protos.String, "string");
cx.bool = new Prim(cx.protos.Boolean, "bool");
cx.num = new Prim(cx.protos.Number, "number");
cx.curOrigin = null;
if (defs) for (var i = 0; i < defs.length; ++i)
def.load(defs[i]);
});
};
exports.Context.prototype.startAnalysis = function() {
this.disabledComputing = this.workList = this.curSuperCtor = this.curSuper = null;
};
var cx = null;
exports.cx = function() { return cx; };
exports.withContext = function(context, f) {
var old = cx;
cx = context;
try { return f(); }
finally { cx = old; }
};
exports.TimedOut = function() {
this.message = "Timed out";
this.stack = (new Error()).stack;
};
exports.TimedOut.prototype = Object.create(Error.prototype);
exports.TimedOut.prototype.name = "infer.TimedOut";
var timeout;
exports.withTimeout = function(ms, f) {
var end = +new Date + ms;
var oldEnd = timeout;
if (oldEnd && oldEnd < end) return f();
timeout = end;
try { return f(); }
finally { timeout = oldEnd; }
};
exports.addOrigin = function(origin) {
if (cx.origins.indexOf(origin) < 0) cx.origins.push(origin);
};
var baseMaxWorkDepth = 20, reduceMaxWorkDepth = 0.0001;
function withWorklist(f) {
if (cx.workList) return f(cx.workList);
var list = [], depth = 0;
var add = cx.workList = function(type, target, weight) {
if (depth < baseMaxWorkDepth - reduceMaxWorkDepth * list.length)
list.push(type, target, weight, depth);
};
var ret = f(add);
for (var i = 0; i < list.length; i += 4) {
if (timeout && +new Date >= timeout)
throw new exports.TimedOut();
depth = list[i + 3] + 1;
list[i + 1].addType(list[i], list[i + 2]);
}
cx.workList = null;
return ret;
}
function withSuper(ctor, obj, f) {
var oldCtor = cx.curSuperCtor, oldObj = cx.curSuper
cx.curSuperCtor = ctor; cx.curSuper = obj
var result = f()
cx.curSuperCtor = oldCtor; cx.curSuper = oldObj
return result
}
// SCOPES
var Scope = exports.Scope = function(prev, originNode, isBlock) {
Obj.call(this, prev || true);
this.prev = prev;
this.originNode = originNode
this.isBlock = !!isBlock
};
Scope.prototype = extend(Obj.prototype, {
constructor: Scope,
defVar: function(name, originNode) {
for (var s = this; ; s = s.proto) {
var found = s.props[name];
if (found) return found;
if (!s.prev) return s.defProp(name, originNode);
}
}
});
function functionScope(scope) {
while (scope.isBlock) scope = scope.prev
return scope
}
// RETVAL COMPUTATION HEURISTICS
function maybeInstantiate(scope, score) {
var fn = functionScope(scope).fnType
if (fn) fn.instantiateScore = (fn.instantiateScore || 0) + score;
}
var NotSmaller = {};
function nodeSmallerThan(node, n) {
try {
walk.simple(node, {Expression: function() { if (--n <= 0) throw NotSmaller; }});
return true;
} catch(e) {
if (e == NotSmaller) return false;
throw e;
}
}
function maybeTagAsInstantiated(node, fn) {
var score = fn.instantiateScore;
if (!cx.disabledComputing && score && fn.args.length && nodeSmallerThan(node, score * 5)) {
maybeInstantiate(functionScope(fn.originNode.scope.prev), score / 2);
setFunctionInstantiated(node, fn);
return true;
} else {
fn.instantiateScore = null;
}
}
function setFunctionInstantiated(node, fn) {
// Disconnect the arg avals, so that we can add info to them without side effects
for (var i = 0; i < fn.args.length; ++i) fn.args[i] = new AVal;
fn.self = new AVal;
fn.computeRet = function(self, args) {
// Prevent recursion
return withDisabledComputing(fn, function() {
var oldOrigin = cx.curOrigin;
cx.curOrigin = fn.origin;
var scope = node.scope
var scopeCopy = new Scope(scope.prev, scope.originNode);
for (var v in scope.props) {
var local = scopeCopy.defProp(v, scope.props[v].originNode);
for (var i = 0; i < args.length; ++i) if (fn.argNames[i] == v && i < args.length)
args[i].propagate(local);
}
var argNames = fn.argNames.length != args.length ? fn.argNames.slice(0, args.length) : fn.argNames;
while (argNames.length < args.length) argNames.push("?");
scopeCopy.fnType = new Fn(fn.name, self, args, argNames, ANull, fn.generator);
scopeCopy.fnType.originNode = fn.originNode;
if (fn.arguments) {
var argset = scopeCopy.fnType.arguments = new AVal;
scopeCopy.defProp("arguments").addType(new Arr(argset));
for (var i = 0; i < args.length; ++i) args[i].propagate(argset);
}
node.scope = scopeCopy;
walk.recursive(node.body, scopeCopy, null, scopeGatherer);
walk.recursive(node.body, scopeCopy, null, inferWrapper);
cx.curOrigin = oldOrigin;
return scopeCopy.fnType.retval;
});
};
}
function maybeTagAsGeneric(fn) {
var target = fn.retval;
if (target == ANull) return;
var targetInner, asArray;
if (!target.isEmpty() && (targetInner = target.getType()) instanceof Arr)
target = asArray = targetInner.getProp("<i>");
function explore(aval, path, depth) {
if (depth > 3 || !aval.forward) return;
for (var i = 0; i < aval.forward.length; ++i) {
var prop = aval.forward[i].propagatesTo();
if (!prop) continue;
var newPath = path, dest;
if (prop instanceof AVal) {
dest = prop;
} else if (prop.target instanceof AVal) {
newPath += prop.pathExt;
dest = prop.target;
} else continue;
if (dest == target) return newPath;
var found = explore(dest, newPath, depth + 1);
if (found) return found;
}
}
var foundPath = explore(fn.self, "!this", 0);
for (var i = 0; !foundPath && i < fn.args.length; ++i)
foundPath = explore(fn.args[i], "!" + i, 0);
if (foundPath) {
if (asArray) foundPath = "[" + foundPath + "]";
var p = new def.TypeParser(foundPath);
var parsed = p.parseType(true);
fn.computeRet = parsed.apply ? parsed : function() { return parsed; };
fn.computeRetSource = foundPath;
return true;
}
}
// SCOPE GATHERING PASS
function addVar(scope, nameNode) {
return scope.defProp(nameNode.name, nameNode);
}
function patternName(node) {
if (node.type == "Identifier") return node.name
if (node.type == "AssignmentPattern") return patternName(node.left)
if (node.type == "ObjectPattern") return "{" + node.properties.map(function(e) { return patternName(e.value) }).join(", ") + "}"
if (node.type == "ArrayPattern") return "[" + node.elements.map(patternName).join(", ") + "]"
if (node.type == "RestElement") return "..." + patternName(node.argument)
return "_"
}
function isBlockScopedDecl(node) {
return node.type == "VariableDeclaration" && node.kind != "var" ||
node.type == "FunctionDeclaration" ||
node.type == "ClassDeclaration";
}
function patternScopes(inner, outer) {
return {inner: inner, outer: outer || inner}
}
var scopeGatherer = exports.scopeGatherer = walk.make({
VariablePattern: function(node, scopes) {
if (scopes.inner) addVar(scopes.inner, node)
},
AssignmentPattern: function(node, scopes, c) {
c(node.left, scopes, "Pattern")
c(node.right, scopes.outer, "Expression")
},
AssignmentExpression: function(node, scope, c) {
if (node.left.type == "MemberExpression")
c(node.left, scope, "Expression")
else
c(node.left, patternScopes(false, scope), "Pattern")
c(node.right, scope, "Expression")
},
Function: function(node, scope, c) {
var inner = node.scope = new Scope(scope, node)
var argVals = [], argNames = []
for (var i = 0; i < node.params.length; ++i) {
var param = node.params[i]
argNames.push(patternName(param))
if (param.type == "Identifier") {
argVals.push(addVar(inner, param))
} else {
var arg = new AVal
argVals.push(arg)
arg.originNode = param
c(param, patternScopes(inner), "Pattern")
}
}
inner.fnType = new Fn(node.id && node.id.name, new AVal, argVals, argNames, ANull, node.generator)
inner.fnType.originNode = node;
if (node.id) {
var decl = node.type == "FunctionDeclaration";
addVar(decl ? scope : inner, node.id);
}
c(node.body, inner, node.expression ? "Expression" : "Statement");
},
BlockStatement: function(node, scope, c) {
if (!node.scope && node.body.some(isBlockScopedDecl))
scope = node.scope = new Scope(scope, node, true)
walk.base.BlockStatement(node, scope, c)
},
TryStatement: function(node, scope, c) {
c(node.block, scope, "Statement");
if (node.handler) {
if (node.handler.param.type == "Identifier") {
var v = addVar(scope, node.handler.param);
c(node.handler.body, scope, "Statement");
var e5 = cx.definitions.ecma5;
if (e5 && v.isEmpty()) getInstance(e5["Error.prototype"]).propagate(v, WG_CATCH_ERROR);
} else {
c(node.handler.param, patternScopes(scope), "Pattern")
}
}
if (node.finalizer) c(node.finalizer, scope, "Statement");
},
VariableDeclaration: function(node, scope, c) {
var targetScope = node.kind == "var" ? functionScope(scope) : scope
for (var i = 0; i < node.declarations.length; ++i) {
var decl = node.declarations[i];
c(decl.id, patternScopes(targetScope, scope), "Pattern")
if (decl.init) c(decl.init, scope, "Expression");
}
},
ClassDeclaration: function(node, scope, c) {
addVar(scope, node.id)
if (node.superClass) c(node.superClass, scope, "Expression")
for (var i = 0; i < node.body.body.length; i++)
c(node.body.body[i], scope)
},
ForInStatement: function(node, scope, c) {
if (!node.scope && isBlockScopedDecl(node.left))
scope = node.scope = new Scope(scope, node, true)
walk.base.ForInStatement(node, scope, c)
},
ForStatement: function(node, scope, c) {
if (!node.scope && node.init && isBlockScopedDecl(node.init))
scope = node.scope = new Scope(scope, node, true)
walk.base.ForStatement(node, scope, c)
},
ImportDeclaration: function(node, scope) {
for (var i = 0; i < node.specifiers.length; i++)
addVar(scope, node.specifiers[i].local)
}
});
scopeGatherer.ForOfStatement = scopeGatherer.ForInStatement
// CONSTRAINT GATHERING PASS
var propName = exports.propName = function(node, inferInScope) {
var key = node.property || node.key;
if (!node.computed && key.type == "Identifier") return key.name;
if (key.type == "Literal") {
if (typeof key.value == "string") return key.value
if (typeof key.value == "number") return String(key.value)
}
if (inferInScope) {
var symName = symbolName(infer(key, inferInScope))
if (symName) return node.propName = symName
} else if (node.propName) {
return node.propName
}
return "<i>";
}
function symbolName(val) {
var sym = val.getSymbolType()
if (sym) return sym.asPropName()
}
function unopResultType(op) {
switch (op) {
case "+": case "-": case "~": return cx.num;
case "!": return cx.bool;
case "typeof": return cx.str;
case "void": case "delete": return ANull;
}
}
function binopIsBoolean(op) {
switch (op) {
case "==": case "!=": case "===": case "!==": case "<": case ">": case ">=": case "<=":
case "in": case "instanceof": return true;
}
}
function literalType(node) {
if (node.regex) return getInstance(cx.protos.RegExp);
switch (typeof node.value) {
case "boolean": return cx.bool;
case "number": return cx.num;
case "string": return cx.str;
case "object":
case "function":
if (!node.value) return ANull;
return getInstance(cx.protos.RegExp);
}
}
function join(a, b) {
if (a == b || b == ANull) return a
if (a == ANull) return b
var joined = new AVal
a.propagate(joined)
b.propagate(joined)
return joined
}
function connectParams(node, scope) {
for (var i = 0; i < node.params.length; i++) {
var param = node.params[i]
if (param.type == "Identifier") continue
connectPattern(param, scope, node.scope.fnType.args[i])
}
}
function ensureVar(node, scope) {
return scope.hasProp(node.name) || cx.topScope.defProp(node.name, node)
}
var inferPatternVisitor = exports.inferPatternVisitor = {
Identifier: function(node, scope, source) {
source.propagate(ensureVar(node, scope))
},
MemberExpression: function(node, scope, source) {
var obj = infer(node.object, scope)
var pName = propName(node, scope)
obj.propagate(new DefProp(pName, source, node.property))
},
RestElement: function(node, scope, source) {
connectPattern(node.argument, scope, new Arr(source))
},
ObjectPattern: function(node, scope, source) {
for (var i = 0; i < node.properties.length; ++i) {
var prop = node.properties[i]
connectPattern(prop.value, scope, source.getProp(prop.key.name))
}
},
ArrayPattern: function(node, scope, source) {
for (var i = 0; i < node.elements.length; i++)
if (node.elements[i])
connectPattern(node.elements[i], scope, source.getProp(String(i)))
},
AssignmentPattern: function(node, scope, source) {
connectPattern(node.left, scope, join(source, infer(node.right, scope)))
}
}
function connectPattern(node, scope, source) {
var connecter = inferPatternVisitor[node.type]
if (connecter) connecter(node, scope, source)
}
function getThis(scope) {
var fnScope = functionScope(scope)
return fnScope.fnType ? fnScope.fnType.self : fnScope
}
function maybeAddPhantomObj(obj) {
if (!obj.isEmpty() || !obj.propertyOf) return
obj.propertyOf.getProp(obj.propertyName).addType(new Obj, WG_PHANTOM_OBJ)
maybeAddPhantomObj(obj.propertyOf)
}
function inferClass(node, scope, name) {
if (!name && node.id) name = node.id.name
var sup = cx.protos.Object, supCtor, delayed
if (node.superClass) {
if (node.superClass.type == "Literal" && node.superClass.value == null) {
sup = null
} else {
var supVal = infer(node.superClass, scope), supProto
supCtor = supVal.getFunctionType()
if (supCtor && (supProto = supCtor.getProp("prototype").getObjType())) {
sup = supProto
} else {
supCtor = supVal
delayed = supVal.getProp("prototype")
}
}
}
var proto = new Obj(sup, name && name + ".prototype")
if (delayed) delayed.propagate(new HasProto(proto))
return withSuper(supCtor, delayed || sup, function() {
var ctor, body = node.body.body
for (var i = 0; i < body.length; i++)
if (body[i].kind == "constructor") ctor = body[i].value
var fn = node.objType = ctor ? infer(ctor, scope) : new Fn(name, ANull, [], null, ANull)
fn.originNode = node.id || ctor || node
var inst = getInstance(proto, fn)
fn.self.addType(inst)
fn.defProp("prototype", node).addType(proto)
for (var i = 0; i < body.length; i++) {
var method = body[i], target
if (method.kind == "constructor") continue
var pName = propName(method, scope)
if (pName == "<i>" || method.kind == "set") {
target = ANull
} else {
target = (method.static ? fn : proto).defProp(pName, method.key)
target.initializer = true
if (method.kind == "get") target = new IsCallee(inst, [], null, target)
}
infer(method.value, scope, target)
var methodFn = target.getFunctionType()
if (methodFn) methodFn.self.addType(inst)
}
return fn
})
}
function arrayLiteralType(elements, scope, inner) {
var tuple = elements.length > 1 && elements.length < 6
if (tuple) {
var homogenous = true, litType
for (var i = 0; i < elements.length; i++) {
var elt = elements[i]
if (!elt)
tuple = false
else if (elt.type != "Literal" || (litType && litType != typeof elt.value))
homogenous = false
else
litType = typeof elt.value
}
if (homogenous) tuple = false
}
if (tuple) {
var types = []
for (var i = 0; i < elements.length; ++i)
types.push(inner(elements[i], scope))
return new Arr(types)
} else if (elements.length < 2) {
return new Arr(elements[0] && inner(elements[0], scope))
} else {
var eltVal = new AVal
for (var i = 0; i < elements.length; i++)
if (elements[i]) inner(elements[i], scope).propagate(eltVal)
return new Arr(eltVal)
}
}
function ret(f) {
return function(node, scope, out, name) {
var r = f(node, scope, name);
if (out) r.propagate(out);
return r;
};
}
function fill(f) {
return function(node, scope, out, name) {
if (!out) out = new AVal;
f(node, scope, out, name);
return out;
};
}
var inferExprVisitor = exports.inferExprVisitor = {
ArrayExpression: ret(function(node, scope) {
return arrayLiteralType(node.elements, scope, infer)
}),
ObjectExpression: ret(function(node, scope, name) {
var proto = true, waitForProto
for (var i = 0; i < node.properties.length; ++i) {
var prop = node.properties[i]
if (prop.key.name == "__proto__") {
if (prop.value.type == "Literal" && prop.value.value == null) {
proto = null
} else {
var protoVal = infer(prop.value, scope), known = protoVal.getObjType()
if (known) proto = known
else waitForProto = protoVal
}
}
}
var obj = node.objType = new Obj(proto, name);
if (waitForProto) waitForProto.propagate(new HasProto(obj))
obj.originNode = node;
withSuper(null, waitForProto || proto, function() {
for (var i = 0; i < node.properties.length; ++i) {
var prop = node.properties[i], key = prop.key;
if (prop.value.name == "✖" || prop.key.name == "__proto__") continue;
var name = propName(prop, scope), target
if (name == "<i>" || prop.kind == "set") {
target = ANull;
} else {
var val = target = obj.defProp(name, key);
val.initializer = true;
if (prop.kind == "get")
target = new IsCallee(obj, [], null, val);
}
infer(prop.value, scope, target, name);
if (prop.value.type == "FunctionExpression")
prop.value.scope.fnType.self.addType(obj, WG_SPECULATIVE_THIS);
}
})
return obj;
}),
FunctionExpression: ret(function(node, scope, name) {
var inner = node.scope, fn = inner.fnType;
if (name && !fn.name) fn.name = name;
connectParams(node, inner)
if (node.expression)
infer(node.body, inner, inner.fnType.retval = new AVal)
else
walk.recursive(node.body, inner, null, inferWrapper, "Statement")
if (node.type == "ArrowFunctionExpression") {
getThis(scope).propagate(fn.self)
fn.self = ANull
}
maybeTagAsInstantiated(node, fn) || maybeTagAsGeneric(fn);
if (node.id) inner.getProp(node.id.name).addType(fn);
return fn;
}),
ClassExpression: ret(inferClass),
SequenceExpression: ret(function(node, scope) {
for (var i = 0, l = node.expressions.length - 1; i < l; ++i)
infer(node.expressions[i], scope, ANull);
return infer(node.expressions[l], scope);
}),
UnaryExpression: ret(function(node, scope) {
infer(node.argument, scope, ANull);
return unopResultType(node.operator);
}),
UpdateExpression: ret(function(node, scope) {
infer(node.argument, scope, ANull);
return cx.num;
}),
BinaryExpression: ret(function(node, scope) {
if (node.operator == "+") {
var lhs = infer(node.left, scope);
var rhs = infer(node.right, scope);
if (lhs.hasType(cx.str) || rhs.hasType(cx.str)) return cx.str;
if (lhs.hasType(cx.num) && rhs.hasType(cx.num)) return cx.num;
var result = new AVal;
lhs.propagate(new IsAdded(rhs, result));
rhs.propagate(new IsAdded(lhs, result));
return result;
} else {
infer(node.left, scope, ANull);
infer(node.right, scope, ANull);
return binopIsBoolean(node.operator) ? cx.bool : cx.num;
}
}),
AssignmentExpression: ret(function(node, scope, name) {
var rhs, pName;
if (node.left.type == "MemberExpression") {
pName = propName(node.left, scope)
if (!name)
name = node.left.object.type == "Identifier" ? node.left.object.name + "." + pName : pName
} else if (!name && node.left.type == "Identifier") {
name = node.left.name
}
if (node.operator && node.operator != "=" && node.operator != "+=") {
infer(node.right, scope, ANull);
rhs = cx.num;
} else {
rhs = infer(node.right, scope, null, name);
}
if (node.left.type == "MemberExpression") {
var obj = infer(node.left.object, scope);
if (pName == "prototype") maybeInstantiate(scope, 20);
if (pName == "<i>") {
// This is a hack to recognize for/in loops that copy
// properties, and do the copying ourselves, insofar as we
// manage, because such loops tend to be relevant for type
// information.
var v = node.left.property.name, local = scope.props[v], over = local && local.iteratesOver;
if (over) {
maybeInstantiate(scope, 20);
var fromRight = node.right.type == "MemberExpression" && node.right.computed && node.right.property.name == v;
over.forAllProps(function(prop, val, local) {
if (local && prop != "prototype" && prop != "<i>")
obj.propagate(new DefProp(prop, fromRight ? val : ANull));
});
return rhs;
}
}
obj.propagate(new DefProp(pName, rhs, node.left.property));
maybeAddPhantomObj(obj)
if (node.right.type == "FunctionExpression")
obj.propagate(node.right.scope.fnType.self, WG_SPECULATIVE_THIS);
} else {
connectPattern(node.left, scope, rhs)
}
return rhs;
}),
LogicalExpression: fill(function(node, scope, out) {
infer(node.left, scope, out);
infer(node.right, scope, out);
}),
ConditionalExpression: fill(function(node, scope, out) {
infer(node.test, scope, ANull);
infer(node.consequent, scope, out);
infer(node.alternate, scope, out);
}),
NewExpression: fill(function(node, scope, out, name) {
if (node.callee.type == "Identifier" && node.callee.name in scope.props)
maybeInstantiate(scope, 20);
for (var i = 0, args = []; i < node.arguments.length; ++i)
args.push(infer(node.arguments[i], scope));
var callee = infer(node.callee, scope);
var self = new AVal;
callee.propagate(new IsCtor(self, name && /\.prototype$/.test(name)));
self.propagate(out, WG_NEW_INSTANCE);
callee.propagate(new IsCallee(self, args, node.arguments, new IfObj(out)));
}),
CallExpression: fill(function(node, scope, out) {
for (var i = 0, args = []; i < node.arguments.length; ++i)
args.push(infer(node.arguments[i], scope));
var outerFn = functionScope(scope).fnType
if (node.callee.type == "MemberExpression") {
var self = infer(node.callee.object, scope);
var pName = propName(node.callee, scope)
if (outerFn && (pName == "call" || pName == "apply") &&
outerFn.args.indexOf(self) > -1)
maybeInstantiate(scope, 30);
self.propagate(new HasMethodCall(pName, args, node.arguments, out));
} else if (node.callee.type == "Super" && cx.curSuperCtor) {
cx.curSuperCtor.propagate(new IsCallee(getThis(scope), args, node.arguments, out))
} else {
var callee = infer(node.callee, scope);
if (outerFn && outerFn.args.indexOf(callee) > -1)
maybeInstantiate(scope, 30);
var knownFn = callee.getFunctionType();
if (knownFn && knownFn.instantiateScore && outerFn)
maybeInstantiate(scope, knownFn.instantiateScore / 5);
callee.propagate(new IsCallee(cx.topScope, args, node.arguments, out));
}
}),
MemberExpression: fill(function(node, scope, out) {
var name = propName(node), wg;
if (name == "<i>") {
var propType = infer(node.property, scope)
var symName = symbolName(propType)
if (symName)
name = node.propName = symName
else if (!propType.hasType(cx.num))
wg = WG_MULTI_MEMBER
}
infer(node.object, scope).getProp(name).propagate(out, wg)
}),
Identifier: ret(function(node, scope) {
if (node.name == "arguments") {
var fnScope = functionScope(scope)
if (fnScope.fnType && !(node.name in fnScope.props))
scope.defProp(node.name, fnScope.fnType.originNode)
.addType(new Arr(fnScope.fnType.arguments = new AVal));
}
return scope.getProp(node.name);
}),
ThisExpression: ret(function(_node, scope) {
return getThis(scope)
}),
Super: ret(function(node) {
return node.superType = cx.curSuper || ANull
}),
Literal: ret(function(node) {
return literalType(node);
}),
TemplateLiteral: ret(function(node, scope) {
for (var i = 0; i < node.expressions.length; ++i)
infer(node.expressions[i], scope, ANull)
return cx.str
}),
TaggedTemplateExpression: fill(function(node, scope, out) {
var args = [new Arr(cx.str)]
for (var i = 0; i < node.quasi.expressions.length; ++i)
args.push(infer(node.quasi.expressions[i], scope))
infer(node.tag, scope, new IsCallee(cx.topScope, args, node.quasi.expressions, out))
}),
YieldExpression: ret(function(node, scope) {
var output = ANull, fn = functionScope(scope).fnType
if (fn) {
if (fn.retval == ANull) fn.retval = new AVal
if (!fn.yieldval) fn.yieldval = new AVal
output = fn.retval
}
if (node.argument) {
if (node.delegate) {
infer(node.argument, scope, new HasMethodCall("next", [], null,
new GetProp("value", output)))
} else {
infer(node.argument, scope, output)
}
}
return fn ? fn.yieldval : ANull
})
};
inferExprVisitor.ArrowFunctionExpression = inferExprVisitor.FunctionExpression
function infer(node, scope, out, name) {
var handler = inferExprVisitor[node.type];
return handler ? handler(node, scope, out, name) : ANull;
}
function loopPattern(init) {
return init.type == "VariableDeclaration" ? init.declarations[0].id : init
}
var inferWrapper = exports.inferWrapper = walk.make({
Expression: function(node, scope) {
infer(node, node.scope || scope, ANull);
},
FunctionDeclaration: function(node, scope, c) {
var inner = node.scope, fn = inner.fnType;
connectParams(node, inner)
c(node.body, inner, "Statement");
maybeTagAsInstantiated(node, fn) || maybeTagAsGeneric(fn);
scope.getProp(node.id.name).addType(fn)
},
Statement: function(node, scope, c) {
c(node, node.scope || scope)
},
VariableDeclaration: function(node, scope) {
for (var i = 0; i < node.declarations.length; ++i) {
var decl = node.declarations[i];
if (decl.id.type == "Identifier") {
var prop = scope.getProp(decl.id.name);
if (decl.init)
infer(decl.init, scope, prop, decl.id.name);
} else if (decl.init) {
connectPattern(decl.id, scope, infer(decl.init, scope))
}
}
},
ClassDeclaration: function(node, scope) {
scope.getProp(node.id.name).addType(inferClass(node, scope, node.id.name))
},
ReturnStatement: function(node, scope) {
if (!node.argument) return;
var output = ANull, fn = functionScope(scope).fnType
if (fn) {
if (fn.retval == ANull) fn.retval = new AVal;
output = fn.retval;
}
infer(node.argument, scope, output);
},
ForInStatement: function(node, scope, c) {
var source = infer(node.right, scope);
if ((node.right.type == "Identifier" && node.right.name in scope.props) ||
(node.right.type == "MemberExpression" && node.right.property.name == "prototype")) {
maybeInstantiate(scope, 5);
var pattern = loopPattern(node.left)
if (pattern.type == "Identifier") {
if (pattern.name in scope.props)
scope.getProp(pattern.name).iteratesOver = source
source.getProp("<i>").propagate(ensureVar(pattern, scope))
} else {
connectPattern(pattern, scope, source.getProp("<i>"))
}
}
c(node.body, scope, "Statement");
},
ForOfStatement: function(node, scope, c) {
var pattern = loopPattern(node.left), target
if (pattern.type == "Identifier")
target = ensureVar(pattern, scope)
else
connectPattern(pattern, scope, target = new AVal)
infer(node.right, scope, new HasMethodCall(":Symbol.iterator", [], null,
new HasMethodCall("next", [], null,
new GetProp("value", target))))
c(node.body, scope, "Statement")
}
});
// PARSING
var parse = exports.parse = function(text, options, thirdArg) {
if (!options || Array.isArray(options)) options = thirdArg
var ast;
try { ast = acorn.parse(text, options); }
catch(e) { ast = acorn_loose.parse_dammit(text, options); }
return ast;
};
// ANALYSIS INTERFACE
exports.analyze = function(ast, name, scope) {
if (typeof ast == "string") ast = parse(ast);
if (!name) name = "file#" + cx.origins.length;
exports.addOrigin(cx.curOrigin = name);
if (!scope) scope = cx.topScope;
cx.startAnalysis();
walk.recursive(ast, scope, null, scopeGatherer);
if (cx.parent) cx.parent.signal("preInfer", ast, scope)
walk.recursive(ast, scope, null, inferWrapper);
if (cx.parent) cx.parent.signal("postInfer", ast, scope)
cx.curOrigin = null;
};
// PURGING
exports.purge = function(origins, start, end) {
var test = makePredicate(origins, start, end);
++cx.purgeGen;
cx.topScope.purge(test);
for (var prop in cx.props) {
var list = cx.props[prop];
for (var i = 0; i < list.length; ++i) {
var obj = list[i], av = obj.props[prop];
if (!av || test(av, av.originNode)) list.splice(i--, 1);
}
if (!list.length) delete cx.props[prop];
}
};
function makePredicate(origins, start, end) {
var arr = Array.isArray(origins);
if (arr && origins.length == 1) { origins = origins[0]; arr = false; }
if (arr) {
if (end == null) return function(n) { return origins.indexOf(n.origin) > -1; };
return function(n, pos) { return pos && pos.start >= start && pos.end <= end && origins.indexOf(n.origin) > -1; };
} else {
if (end == null) return function(n) { return n.origin == origins; };
return function(n, pos) { return pos && pos.start >= start && pos.end <= end && n.origin == origins; };
}
}
AVal.prototype.purge = function(test) {
if (this.purgeGen == cx.purgeGen) return;
this.purgeGen = cx.purgeGen;
for (var i = 0; i < this.types.length; ++i) {
var type = this.types[i];
if (test(type, type.originNode))
this.types.splice(i--, 1);
else
type.purge(test);
}
if (!this.types.length) this.maxWeight = 0;
if (this.forward) for (var i = 0; i < this.forward.length; ++i) {
var f = this.forward[i];
if (test(f)) {
this.forward.splice(i--, 1);
if (this.props) this.props = null;
} else if (f.purge) {
f.purge(test);
}
}
};
ANull.purge = function() {};
Obj.prototype.purge = function(test) {
if (this.purgeGen == cx.purgeGen) return true;
this.purgeGen = cx.purgeGen;
for (var p in this.props) {
var av = this.props[p];
if (test(av, av.originNode))
this.removeProp(p);
av.purge(test);
}
};
Fn.prototype.purge = function(test) {
if (Obj.prototype.purge.call(this, test)) return;
this.self.purge(test);
this.retval.purge(test);
for (var i = 0; i < this.args.length; ++i) this.args[i].purge(test);
};
// EXPRESSION TYPE DETERMINATION
function findByPropertyName(name) {
guessing = true;
var found = objsWithProp(name);
if (found) for (var i = 0; i < found.length; ++i) {
var val = found[i].getProp(name);
if (!val.isEmpty()) return val;
}
return ANull;
}
function generatorResult(input, output) {
var retObj = new Obj(true)
retObj.defProp("done").addType(cx.bool)
output.propagate(retObj.defProp("value"))
var method = new Fn(null, ANull, input ? [input] : [], input ? ["?"] : [], retObj)
var result = new Obj(cx.definitions.ecma6 && cx.definitions.ecma6.generator_prototype || true)
result.defProp("next").addType(method)
return result
}
function maybeIterator(fn, output) {
if (!fn.generator) return output
if (!fn.computeRet) { // Reuse iterator objects for non-computed return types
if (fn.generator === true) fn.generator = generatorResult(fn.yieldval, output)
return fn.generator
}
return generatorResult(fn.yieldval, output)
}
function computeReturnType(funcNode, argNodes, scope) {
var fn = findType(funcNode, scope).getFunctionType()
if (!fn) return ANull
var result = fn.retval
if (fn.computeRet) {
for (var i = 0, args = []; i < argNodes.length; ++i)
args.push(findType(argNodes[i], scope))
var self = ANull
if (funcNode.type == "MemberExpression")
self = findType(funcNode.object, scope)
result = fn.computeRet(self, args, argNodes);
}
return maybeIterator(fn, result)
}
var typeFinder = exports.typeFinder = {
ArrayExpression: function(node, scope) {
return arrayLiteralType(node.elements, scope, findType)
},
ObjectExpression: function(node) {
return node.objType;
},
ClassExpression: function(node) {
return node.objType;
},
FunctionExpression: function(node) {
return node.scope.fnType;
},
ArrowFunctionExpression: function(node) {
return node.scope.fnType;
},
SequenceExpression: function(node, scope) {
return findType(node.expressions[node.expressions.length-1], scope);
},
UnaryExpression: function(node) {
return unopResultType(node.operator);
},
UpdateExpression: function() {
return cx.num;
},
BinaryExpression: function(node, scope) {
if (binopIsBoolean(node.operator)) return cx.bool;
if (node.operator == "+") {
var lhs = findType(node.left, scope);
var rhs = findType(node.right, scope);
if (lhs.hasType(cx.str) || rhs.hasType(cx.str)) return cx.str;
}
return cx.num;
},
AssignmentExpression: function(node, scope) {
return findType(node.right, scope);
},
LogicalExpression: function(node, scope) {
var lhs = findType(node.left, scope);
return lhs.isEmpty() ? findType(node.right, scope) : lhs;
},
ConditionalExpression: function(node, scope) {
var lhs = findType(node.consequent, scope);
return lhs.isEmpty() ? findType(node.alternate, scope) : lhs;
},
NewExpression: function(node, scope) {
var f = findType(node.callee, scope).getFunctionType();
var proto = f && f.getProp("prototype").getObjType();
if (!proto) return ANull;
return getInstance(proto, f);
},
CallExpression: function(node, scope) {
return computeReturnType(node.callee, node.arguments, scope)
},
MemberExpression: function(node, scope) {
var propN = propName(node), obj = findType(node.object, scope).getType();
if (obj) return obj.getProp(propN);
if (propN == "<i>") return ANull;
return findByPropertyName(propN);
},
Identifier: function(node, scope) {
return scope.hasProp(node.name) || ANull;
},
ThisExpression: function(_node, scope) {
return getThis(scope)
},
Literal: function(node) {
return literalType(node);
},
Super: ret(function(node) {
return node.superType
}),
TemplateLiteral: function() {
return cx.str
},
TaggedTemplateExpression: function(node, scope) {
return computeReturnType(node.tag, node.quasi.expressions, scope)
},
YieldExpression: function(_node, scope) {
var fn = functionScope(scope).fnType
return fn ? fn.yieldval : ANull
}
};
function findType(node, scope) {
var finder = typeFinder[node.type];
return finder ? finder(node, scope) : ANull;
}
var searchVisitor = exports.searchVisitor = walk.make({
Function: function(node, _st, c) {
walk.base.Function(node, node.scope, c)
},
Property: function(node, st, c) {
if (node.computed) c(node.key, st, "Expression");
if (node.key != node.value) c(node.value, st, "Expression");
},
Statement: function(node, st, c) {
c(node, node.scope || st)
},
ImportSpecifier: function(node, st, c) {
c(node.local, st)
},
ImportDefaultSpecifier: function(node, st, c) {
c(node.local, st)
},
ImportNamespaceSpecifier: function(node, st, c) {
c(node.local, st)
}
});
exports.fullVisitor = walk.make({
MemberExpression: function(node, st, c) {
c(node.object, st, "Expression");
c(node.property, st, node.computed ? "Expression" : null);
},
ObjectExpression: function(node, st, c) {
for (var i = 0; i < node.properties.length; ++i) {
c(node.properties[i].value, st, "Expression");
c(node.properties[i].key, st);
}
}
}, searchVisitor);
exports.findExpressionAt = function(ast, start, end, defaultScope, filter) {
var test = filter || function(_t, node) {
if (node.type == "Identifier" && node.name == "✖") return false;
return typeFinder.hasOwnProperty(node.type);
};
return walk.findNodeAt(ast, start, end, test, searchVisitor, defaultScope || cx.topScope);
};
exports.findExpressionAround = function(ast, start, end, defaultScope, filter) {
var test = filter || function(_t, node) {
if (start != null && node.start > start) return false;
if (node.type == "Identifier" && node.name == "✖") return false;
return typeFinder.hasOwnProperty(node.type);
};
return walk.findNodeAround(ast, end, test, searchVisitor, defaultScope || cx.topScope);
};
exports.expressionType = function(found) {
return findType(found.node, found.state);
};
// Finding the expected type of something, from context
exports.parentNode = function(child, ast) {
var stack = [];
function c(node, st, override) {
if (node.start <= child.start && node.end >= child.end) {
var top = stack[stack.length - 1];
if (node == child) throw {found: top};
if (top != node) stack.push(node);
walk.base[override || node.type](node, st, c);
if (top != node) stack.pop();
}
}
try {
c(ast, null);
} catch (e) {
if (e.found) return e.found;
throw e;
}
};
var findTypeFromContext = exports.findTypeFromContext = {
ArrayExpression: function(parent, _, get) { return get(parent, true).getProp("<i>"); },
ObjectExpression: function(parent, node, get) {
for (var i = 0; i < parent.properties.length; ++i) {
var prop = node.properties[i];
if (prop.value == node)
return get(parent, true).getProp(prop.key.name);
}
},
UnaryExpression: function(parent) { return unopResultType(parent.operator); },
UpdateExpression: function() { return cx.num; },
BinaryExpression: function(parent) { return binopIsBoolean(parent.operator) ? cx.bool : cx.num; },
AssignmentExpression: function(parent, _, get) { return get(parent.left); },
LogicalExpression: function(parent, _, get) { return get(parent, true); },
ConditionalExpression: function(parent, node, get) {
if (parent.consequent == node || parent.alternate == node) return get(parent, true);
},
CallExpression: function(parent, node, get) {
for (var i = 0; i < parent.arguments.length; i++) {
var arg = parent.arguments[i];
if (arg == node) {
var calleeType = get(parent.callee).getFunctionType();
if (calleeType instanceof Fn)
return calleeType.args[i];
break;
}
}
},
ReturnStatement: function(_parent, node, get) {
var fnNode = walk.findNodeAround(node.sourceFile.ast, node.start, "Function");
if (fnNode) {
var fnType = fnNode.node.type != "FunctionDeclaration"
? get(fnNode.node, true).getFunctionType()
: fnNode.node.scope.fnType;
if (fnType) return fnType.retval.getType();
}
},
VariableDeclarator: function(parent, node, get) {
if (parent.init == node) return get(parent.id)
}
};
findTypeFromContext.NewExpression = findTypeFromContext.CallExpression
exports.typeFromContext = function(ast, found) {
var parent = exports.parentNode(found.node, ast);
var type = null;
if (findTypeFromContext.hasOwnProperty(parent.type)) {
var finder = findTypeFromContext[parent.type];
type = finder && finder(parent, found.node, function(node, fromContext) {
var obj = {node: node, state: found.state};
var tp = fromContext ? exports.typeFromContext(ast, obj) : exports.expressionType(obj);
return tp || ANull;
});
}
return type || exports.expressionType(found);
};
// Flag used to indicate that some wild guessing was used to produce
// a type or set of completions.
var guessing = false;
exports.resetGuessing = function(val) { guessing = val; };
exports.didGuess = function() { return guessing; };
exports.forAllPropertiesOf = function(type, f) {
type.gatherProperties(f, 0);
};
var refFindWalker = walk.make({}, searchVisitor);
exports.findRefs = function(ast, baseScope, name, refScope, f) {
refFindWalker.Identifier = refFindWalker.VariablePattern = function(node, scope) {
if (node.name != name) return;
for (var s = scope; s; s = s.prev) {
if (s == refScope) f(node, scope);
if (name in s.props) return;
}
};
walk.recursive(ast, baseScope, null, refFindWalker);
};
var simpleWalker = walk.make({
Function: function(node, _scope, c) {
c(node.body, node.scope, node.expression ? "Expression" : "Statement")
},
Statement: function(node, scope, c) {
c(node, node.scope || scope)
}
});
exports.findPropRefs = function(ast, scope, objType, propName, f) {
walk.simple(ast, {
MemberExpression: function(node, scope) {
if (node.computed || node.property.name != propName) return;
if (findType(node.object, scope).getType() == objType) f(node.property);
},
ObjectExpression: function(node, scope) {
if (findType(node, scope).getType() != objType) return;
for (var i = 0; i < node.properties.length; ++i)
if (node.properties[i].key.name == propName) f(node.properties[i].key);
}
}, simpleWalker, scope);
};
// LOCAL-VARIABLE QUERIES
var scopeAt = exports.scopeAt = function(ast, pos, defaultScope) {
var found = walk.findNodeAround(ast, pos, function(_, node) {
return node.scope;
});
if (found) return found.node.scope;
else return defaultScope || cx.topScope;
};
exports.forAllLocalsAt = function(ast, pos, defaultScope, f) {
var scope = scopeAt(ast, pos, defaultScope);
scope.gatherProperties(f, 0);
};
// INIT DEF MODULE
// Delayed initialization because of cyclic dependencies.
def = exports.def = def.init({}, exports);
});