gecko/toolkit/devtools/tern/infer.js
2014-06-24 13:53:00 -04:00

1475 lines
49 KiB
JavaScript
Executable File

// Main type inference engine
// Walks an AST, building up a graph of abstract values and contraints
// 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(mod) {
if (typeof exports == "object" && typeof module == "object") // CommonJS
return mod(exports, require("acorn/acorn"), require("acorn/acorn_loose"), require("acorn/util/walk"),
require("./def"), require("./signal"));
if (typeof define == "function" && define.amd) // AMD
return define(["exports", "acorn/acorn", "acorn/acorn_loose", "acorn/util/walk", "./def", "./signal"], mod);
mod(self.tern || (self.tern = {}), acorn, acorn, acorn.walk, tern.def, tern.signal); // Plain browser env
})(function(exports, acorn, acorn_loose, walk, def, signal) {
"use strict";
var toString = exports.toString = function(type, maxDepth, parent) {
return !type || type == parent ? "?": type.toString(maxDepth);
};
// 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() {},
getType: function() {},
gatherProperties: function() {},
propagatesTo: function() {},
typeHint: function() {},
propHint: function() {}
});
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 = 5,
WG_CATCH_ERROR = 5, WG_GLOBAL_THIS = 90, WG_SPECULATIVE_THIS = 2;
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)) 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 PropIsSubset(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];
},
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);
},
computedPropType: function() {
if (!this.propertyOf || !this.propertyOf.hasProp("<i>")) return null;
var computedProp = this.propertyOf.getProp("<i>");
if (computedProp == this) return null;
return computedProp.getType();
},
makeupType: function() {
var computed = this.computedPropType();
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 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
function Constraint() {}
Constraint.prototype = extend(ANull, {
init: function() { this.origin = cx.curOrigin; }
});
var constraint = exports.constraint = function(props, methods) {
var body = "this.init();";
props = props ? props.split(", ") : [];
for (var i = 0; i < props.length; ++i)
body += "this." + props[i] + " = " + props[i] + ";";
var ctor = Function.apply(null, props.concat([body]));
ctor.prototype = Object.create(Constraint.prototype);
for (var m in methods) if (methods.hasOwnProperty(m)) ctor.prototype[m] = methods[m];
return ctor;
};
var PropIsSubset = constraint("prop, 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 PropHasSubset = exports.PropHasSubset = constraint("prop, type, originNode", {
addType: function(type, weight) {
if (!(type instanceof Obj)) return;
var prop = type.defProp(this.prop, this.originNode);
prop.origin = this.origin;
this.type.propagate(prop, weight);
},
propHint: function() { return this.prop; }
});
var ForAllProps = constraint("c", {
addType: function(type) {
if (!(type instanceof Obj)) return;
type.forAllProps(this.c);
}
});
function withDisabledComputing(fn, body) {
cx.disabledComputing = {fn: fn, prev: cx.disabledComputing};
try {
return body();
} finally {
cx.disabledComputing = cx.disabledComputing.prev;
}
}
var IsCallee = exports.IsCallee = constraint("self, args, argNodes, retval", {
init: function() {
Constraint.prototype.init();
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;
if (compute) for (var d = this.disabled; d; d = d.prev)
if (d.fn == fn || fn.name && d.fn.name == fn.name) compute = null;
if (compute)
compute(this.self, this.args, this.argNodes).propagate(this.retval, weight);
else
fn.retval.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("propName, args, argNodes, retval", {
init: function() {
Constraint.prototype.init();
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("target, noReuse", {
addType: function(f, weight) {
if (!(f instanceof Fn)) return;
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("ctor, 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("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("other, 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("target", {
addType: function(t, weight) {
if (t instanceof Obj) this.target.addType(t, weight);
},
propagatesTo: function() { return this.target; }
});
var SpeculativeThis = constraint("obj, ctor", {
addType: function(tp) {
if (tp instanceof Fn && tp.self && tp.self.isEmpty())
tp.self.addType(getInstance(this.obj, this.ctor), WG_SPECULATIVE_THIS);
}
});
var Muffle = constraint("inner, 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);
}
});
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 && 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].getType(), maxDepth - 1));
else
props.push(prop);
}
props.sort();
if (etc) props.push("...");
return "{" + props.join(", ") + "}";
},
hasProp: function(prop, searchProto) {
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 (found.maybePurge) found.maybePurge = false;
if (originNode && !found.originNode) found.originNode = originNode;
return found;
}
if (prop == "__proto__" || prop == "✖") return ANull;
var av = this.maybeProps && this.maybeProps[prop];
if (av) {
delete this.maybeProps[prop];
this.maybeUnregProtoPropHandler();
} else {
av = new AVal;
av.propertyOf = this;
}
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;
var av = this.ensureMaybeProps()[prop] = new AVal;
av.propertyOf = this;
return av;
},
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);
},
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;
},
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>")
f(prop, this, depth);
if (this.proto) this.proto.gatherProperties(f, depth + 1);
}
});
var Fn = exports.Fn = function(name, self, args, argNames, retval) {
Obj.call(this, cx.protos.Function, name);
this.self = self;
this.args = args;
this.argNames = argNames;
this.retval = retval;
};
Fn.prototype = extend(Obj.prototype, {
constructor: Fn,
toString: function(maxDepth) {
if (maxDepth) maxDepth--;
var str = "fn(";
for (var i = 0; i < this.args.length; ++i) {
if (i) str += ", ";
var name = this.argNames[i];
if (name && name != "?") str += name + ": ";
str += toString(this.args[i].getType(), maxDepth, this);
}
str += ")";
if (!this.retval.isEmpty())
str += " -> " + toString(this.retval.getType(), maxDepth, 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 (contentType) contentType.propagate(content);
};
Arr.prototype = extend(Obj.prototype, {
constructor: Arr,
toString: function(maxDepth) {
return "[" + toString(this.getProp("<i>").getType(), maxDepth, this) + "]";
}
});
// 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;
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 Obj(true, "Function.prototype");
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.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]);
});
};
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 = .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);
};
try {
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]);
}
return ret;
} finally {
cx.workList = null;
}
}
// SCOPES
var Scope = exports.Scope = function(prev) {
Obj.call(this, prev || true);
this.prev = prev;
};
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);
}
}
});
// RETVAL COMPUTATION HEURISTICS
function maybeInstantiate(scope, score) {
if (scope.fnType)
scope.fnType.instantiateScore = (scope.fnType.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, scope) {
var score = scope.fnType.instantiateScore;
if (!cx.disabledComputing && score && scope.fnType.args.length && nodeSmallerThan(node, score * 5)) {
maybeInstantiate(scope.prev, score / 2);
setFunctionInstantiated(node, scope);
return true;
} else {
scope.fnType.instantiateScore = null;
}
}
function setFunctionInstantiated(node, scope) {
var fn = scope.fnType;
// 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 scopeCopy = new Scope(scope.prev);
scopeCopy.originNode = 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);
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.body.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(scope) {
var fn = scope.fnType, 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);
fn.computeRet = p.parseRetType();
fn.computeRetSource = foundPath;
return true;
}
}
// SCOPE GATHERING PASS
function addVar(scope, nameNode) {
return scope.defProp(nameNode.name, nameNode);
}
var scopeGatherer = walk.make({
Function: function(node, scope, c) {
var inner = node.body.scope = new Scope(scope);
inner.originNode = node;
var argVals = [], argNames = [];
for (var i = 0; i < node.params.length; ++i) {
var param = node.params[i];
argNames.push(param.name);
argVals.push(addVar(inner, param));
}
inner.fnType = new Fn(node.id && node.id.name, new AVal, argVals, argNames, ANull);
inner.fnType.originNode = node;
if (node.id) {
var decl = node.type == "FunctionDeclaration";
addVar(decl ? scope : inner, node.id);
}
c(node.body, inner, "ScopeBody");
},
TryStatement: function(node, scope, c) {
c(node.block, scope, "Statement");
if (node.handler) {
var v = addVar(scope, node.handler.param);
c(node.handler.body, scope, "ScopeBody");
var e5 = cx.definitions.ecma5;
if (e5 && v.isEmpty()) getInstance(e5["Error.prototype"]).propagate(v, WG_CATCH_ERROR);
}
if (node.finalizer) c(node.finalizer, scope, "Statement");
},
VariableDeclaration: function(node, scope, c) {
for (var i = 0; i < node.declarations.length; ++i) {
var decl = node.declarations[i];
addVar(scope, decl.id);
if (decl.init) c(decl.init, scope, "Expression");
}
}
});
// CONSTRAINT GATHERING PASS
function propName(node, scope, c) {
var prop = node.property;
if (!node.computed) return prop.name;
if (prop.type == "Literal" && typeof prop.value == "string") return prop.value;
if (c) infer(prop, scope, c, ANull);
return "<i>";
}
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(val) {
switch (typeof val) {
case "boolean": return cx.bool;
case "number": return cx.num;
case "string": return cx.str;
case "object":
case "function":
if (!val) return ANull;
return getInstance(cx.protos.RegExp);
}
}
function ret(f) {
return function(node, scope, c, out, name) {
var r = f(node, scope, c, name);
if (out) r.propagate(out);
return r;
};
}
function fill(f) {
return function(node, scope, c, out, name) {
if (!out) out = new AVal;
f(node, scope, c, out, name);
return out;
};
}
var inferExprVisitor = {
ArrayExpression: ret(function(node, scope, c) {
var eltval = new AVal;
for (var i = 0; i < node.elements.length; ++i) {
var elt = node.elements[i];
if (elt) infer(elt, scope, c, eltval);
}
return new Arr(eltval);
}),
ObjectExpression: ret(function(node, scope, c, name) {
var obj = node.objType = new Obj(true, name);
obj.originNode = node;
for (var i = 0; i < node.properties.length; ++i) {
var prop = node.properties[i], key = prop.key, name;
if (key.type == "Identifier") {
name = key.name;
} else if (typeof key.value == "string") {
name = key.value;
} else {
infer(prop.value, scope, c, ANull);
continue;
}
var val = obj.defProp(name, key);
val.initializer = true;
infer(prop.value, scope, c, val, name);
}
return obj;
}),
FunctionExpression: ret(function(node, scope, c, name) {
var inner = node.body.scope, fn = inner.fnType;
if (name && !fn.name) fn.name = name;
c(node.body, scope, "ScopeBody");
maybeTagAsInstantiated(node, inner) || maybeTagAsGeneric(inner);
if (node.id) inner.getProp(node.id.name).addType(fn);
return fn;
}),
SequenceExpression: ret(function(node, scope, c) {
for (var i = 0, l = node.expressions.length - 1; i < l; ++i)
infer(node.expressions[i], scope, c, ANull);
return infer(node.expressions[l], scope, c);
}),
UnaryExpression: ret(function(node, scope, c) {
infer(node.argument, scope, c, ANull);
return unopResultType(node.operator);
}),
UpdateExpression: ret(function(node, scope, c) {
infer(node.argument, scope, c, ANull);
return cx.num;
}),
BinaryExpression: ret(function(node, scope, c) {
if (node.operator == "+") {
var lhs = infer(node.left, scope, c);
var rhs = infer(node.right, scope, c);
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, c, ANull);
infer(node.right, scope, c, ANull);
return binopIsBoolean(node.operator) ? cx.bool : cx.num;
}
}),
AssignmentExpression: ret(function(node, scope, c) {
var rhs, name, pName;
if (node.left.type == "MemberExpression") {
pName = propName(node.left, scope, c);
if (node.left.object.type == "Identifier")
name = node.left.object.name + "." + pName;
} else {
name = node.left.name;
}
if (node.operator != "=" && node.operator != "+=") {
infer(node.right, scope, c, ANull);
rhs = cx.num;
} else {
rhs = infer(node.right, scope, c, null, name);
}
if (node.left.type == "MemberExpression") {
var obj = infer(node.left.object, scope, c);
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 PropHasSubset(prop, fromRight ? val : ANull));
});
return rhs;
}
}
obj.propagate(new PropHasSubset(pName, rhs, node.left.property));
} else { // Identifier
var v = scope.defVar(node.left.name, node.left);
if (v.maybePurge) v.maybePurge = false;
rhs.propagate(v);
}
return rhs;
}),
LogicalExpression: fill(function(node, scope, c, out) {
infer(node.left, scope, c, out);
infer(node.right, scope, c, out);
}),
ConditionalExpression: fill(function(node, scope, c, out) {
infer(node.test, scope, c, ANull);
infer(node.consequent, scope, c, out);
infer(node.alternate, scope, c, out);
}),
NewExpression: fill(function(node, scope, c, 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, c));
var callee = infer(node.callee, scope, c);
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, c, out) {
for (var i = 0, args = []; i < node.arguments.length; ++i)
args.push(infer(node.arguments[i], scope, c));
if (node.callee.type == "MemberExpression") {
var self = infer(node.callee.object, scope, c);
var pName = propName(node.callee, scope, c);
if ((pName == "call" || pName == "apply") &&
scope.fnType && scope.fnType.args.indexOf(self) > -1)
maybeInstantiate(scope, 30);
self.propagate(new HasMethodCall(pName, args, node.arguments, out));
} else {
var callee = infer(node.callee, scope, c);
if (scope.fnType && scope.fnType.args.indexOf(callee) > -1)
maybeInstantiate(scope, 30);
var knownFn = callee.getFunctionType();
if (knownFn && knownFn.instantiateScore && scope.fnType)
maybeInstantiate(scope, knownFn.instantiateScore / 5);
callee.propagate(new IsCallee(cx.topScope, args, node.arguments, out));
}
}),
MemberExpression: fill(function(node, scope, c, out) {
var name = propName(node, scope);
var obj = infer(node.object, scope, c);
var prop = obj.getProp(name);
if (name == "<i>") {
var propType = infer(node.property, scope, c);
if (!propType.hasType(cx.num))
return prop.propagate(out, WG_MULTI_MEMBER);
}
prop.propagate(out);
}),
Identifier: ret(function(node, scope) {
if (node.name == "arguments" && scope.fnType && !(node.name in scope.props))
scope.defProp(node.name, scope.fnType.originNode)
.addType(new Arr(scope.fnType.arguments = new AVal));
return scope.getProp(node.name);
}),
ThisExpression: ret(function(_node, scope) {
return scope.fnType ? scope.fnType.self : cx.topScope;
}),
Literal: ret(function(node) {
return literalType(node.value);
})
};
function infer(node, scope, c, out, name) {
return inferExprVisitor[node.type](node, scope, c, out, name);
}
var inferWrapper = walk.make({
Expression: function(node, scope, c) {
infer(node, scope, c, ANull);
},
FunctionDeclaration: function(node, scope, c) {
var inner = node.body.scope, fn = inner.fnType;
c(node.body, scope, "ScopeBody");
maybeTagAsInstantiated(node, inner) || maybeTagAsGeneric(inner);
var prop = scope.getProp(node.id.name);
prop.addType(fn);
},
VariableDeclaration: function(node, scope, c) {
for (var i = 0; i < node.declarations.length; ++i) {
var decl = node.declarations[i], prop = scope.getProp(decl.id.name);
if (decl.init)
infer(decl.init, scope, c, prop, decl.id.name);
}
},
ReturnStatement: function(node, scope, c) {
if (!node.argument) return;
var output = ANull;
if (scope.fnType) {
if (scope.fnType.retval == ANull) scope.fnType.retval = new AVal;
output = scope.fnType.retval;
}
infer(node.argument, scope, c, output);
},
ForInStatement: function(node, scope, c) {
var source = infer(node.right, scope, c);
if ((node.right.type == "Identifier" && node.right.name in scope.props) ||
(node.right.type == "MemberExpression" && node.right.property.name == "prototype")) {
maybeInstantiate(scope, 5);
var varName;
if (node.left.type == "Identifier") {
varName = node.left.name;
} else if (node.left.type == "VariableDeclaration") {
varName = node.left.declarations[0].id.name;
}
if (varName && varName in scope.props)
scope.getProp(varName).iteratesOver = source;
}
c(node.body, scope, "Statement");
},
ScopeBody: function(node, scope, c) { c(node, node.scope || scope); }
});
// PARSING
function runPasses(passes, pass) {
var arr = passes && passes[pass];
var args = Array.prototype.slice.call(arguments, 2);
if (arr) for (var i = 0; i < arr.length; ++i) arr[i].apply(null, args);
}
var parse = exports.parse = function(text, passes, options) {
var ast;
try { ast = acorn.parse(text, options); }
catch(e) { ast = acorn_loose.parse_dammit(text, options); }
runPasses(passes, "postParse", ast, text);
return ast;
};
// ANALYSIS INTERFACE
exports.analyze = function(ast, name, scope, passes) {
if (typeof ast == "string") ast = parse(ast);
if (!name) name = "file#" + cx.origins.length;
exports.addOrigin(cx.curOrigin = name);
if (!scope) scope = cx.topScope;
walk.recursive(ast, scope, null, scopeGatherer);
runPasses(passes, "preInfer", ast, scope);
walk.recursive(ast, scope, null, inferWrapper);
runPasses(passes, "postInfer", ast, scope);
cx.curOrigin = null;
};
// PURGING
exports.purgeTypes = 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.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;
var props = [];
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);
};
exports.markVariablesDefinedBy = function(scope, origins, start, end) {
var test = makePredicate(origins, start, end);
for (var s = scope; s; s = s.prev) for (var p in s.props) {
var prop = s.props[p];
if (test(prop, prop.originNode)) {
prop.maybePurge = true;
if (start == null && prop.originNode) prop.originNode = null;
}
}
};
exports.purgeMarkedVariables = function(scope) {
for (var s = scope; s; s = s.prev) for (var p in s.props)
if (s.props[p].maybePurge) delete s.props[p];
};
// 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;
}
var typeFinder = {
ArrayExpression: function(node, scope) {
var eltval = new AVal;
for (var i = 0; i < node.elements.length; ++i) {
var elt = node.elements[i];
if (elt) findType(elt, scope).propagate(eltval);
}
return new Arr(eltval);
},
ObjectExpression: function(node) {
return node.objType;
},
FunctionExpression: function(node) {
return node.body.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").getType();
if (!proto) return ANull;
return getInstance(proto, f);
},
CallExpression: function(node, scope) {
var f = findType(node.callee, scope).getFunctionType();
if (!f) return ANull;
if (f.computeRet) {
for (var i = 0, args = []; i < node.arguments.length; ++i)
args.push(findType(node.arguments[i], scope));
var self = ANull;
if (node.callee.type == "MemberExpression")
self = findType(node.callee.object, scope);
return f.computeRet(self, args, node.arguments);
} else {
return f.retval;
}
},
MemberExpression: function(node, scope) {
var propN = propName(node, scope), 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 scope.fnType ? scope.fnType.self : cx.topScope;
},
Literal: function(node) {
return literalType(node.value);
}
};
function findType(node, scope) {
var found = typeFinder[node.type](node, scope);
return found;
}
var searchVisitor = exports.searchVisitor = walk.make({
Function: function(node, _st, c) {
var scope = node.body.scope;
if (node.id) c(node.id, scope);
for (var i = 0; i < node.params.length; ++i)
c(node.params[i], scope);
c(node.body, scope, "ScopeBody");
},
TryStatement: function(node, st, c) {
if (node.handler)
c(node.handler.param, st);
walk.base.TryStatement(node, st, c);
},
VariableDeclaration: function(node, st, c) {
for (var i = 0; i < node.declarations.length; ++i) {
var decl = node.declarations[i];
c(decl.id, st);
if (decl.init) c(decl.init, st, "Expression");
}
}
});
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) {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;
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);
};
// 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 = 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, _st, c) { c(node.body, node.body.scope, "ScopeBody"); }
});
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(tp, node) {
return tp == "ScopeBody" && 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);
});