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simple eval: implement escape analysis
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@gdh1995
gdh1995 committed Aug 20, 2024
1 parent 6bfc745 commit cddde8b
Showing 1 changed file with 95 additions and 8 deletions.
103 changes: 95 additions & 8 deletions lib/simple_eval.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -13,7 +13,8 @@ interface BreakValue { c: BOOL, v: string | 0 }
type VarLiterals = "var1" | "bar" | "..." | "__proto__" | "new.target" | "debugger"
type VarNames = "Var1" | "globalThis" | "this" | "arguments" | "undefined"
type VarDict = { [index: number]: number } & { [name in VarNames]: unknown }
interface StackFrame { readonly v: VarDict, readonly c: readonly VarNames[], n: string | null, r: BOOL }
type Set2<K> = Pick<Set<K>, "has" | "add">
interface StackFrame { readonly v: VarDict, readonly c: readonly VarNames[], n: string | null, r: BOOL|Set2<VarNames> }
interface Isolate extends VarDict {}
interface Ref { readonly y: { [index: number]: number }, readonly i: number /** | ... */ }
interface Function2 { (this: unknown, ...args: unknown[]): unknown; __fn?: OpValues[O.fn] }
Expand Down Expand Up @@ -107,6 +108,7 @@ let NativeFunctionCtor: FunctionConstructor | false | null = !Build.NDEBUG && ty
).runtime.getManifest().content_security_policy).includes("'unsafe-eval'") ? null : false
let isolate_: Isolate = DefaultIsolate, locals_: StackFrame[] = [], stackDepth_ = 0
let g_exc: { g: Isolate, l: StackFrame[], d: number } | null = null
let _collect: { (op: SomeOps<O.block | O.stat | O.fn>, enter: BOOL): void; (o: RefOp, v: VarNames): void } | null = null

//#endregion configurations

Expand Down Expand Up @@ -173,6 +175,15 @@ const globalVarAccessor = {
set eval (_value: unknown) { /* empty */ }
} as unknown as Ref["y"]
const VarName = (name: VarLiterals): VarNames => (name !== kProto ? name : name + ".") as VarNames
const Set_add = function <T> (this: T[] & Set<T>, i: T) { this.indexOf(i) >= 0 || this.push(i); return this }
const Set_has = function <T> (this: T[] & Set<T>, i: T) { return this.indexOf(i) >= 0 }
const kHasSet = !(Build.BTypes & BrowserType.Chrome) || Build.MinCVer >= BrowserVer.Min$Array$$From
&& Build.MinCVer >= BrowserVer.MinEnsuredES6$ForOf$Map$SetAnd$Symbol || !!Array.from
const Set2 = kHasSet ? <T> (): Set2<T> => new Set!<T>() : (<T> (): Set2<T> => {
const a = [] as T[] as T[] & Set<T>
a.add = Set_add, a.has = Set_has
return a
}) as never

//#endregion helper functions

Expand Down Expand Up @@ -586,6 +597,45 @@ const parseTree = (tokens_: readonly Token[], inNewFunc: boolean | null | undefi
return values_.length === 2 && values_[1].o !== O.stat && !inNewFunc ? values_[1] : (consume(), values_[0])
}

const analyseEscaped = (func: BaseOp<O.fn>): void => {
const visited: { readonly d: NullableVarList, readonly r: Set2<VarNames> }[] = []
_collect = (op, enter): void => {
if (op.o === O.token) {
let val = enter as VarNames, i = visited.length - 1, decl: NullableVarList
if (visited[i].r.has(val) || (val as VarNames | VarLiterals) === "...") { return }
for (; (decl = visited[i].d) !== 0 && decl.indexOf(val) < 0; i--) { /* empty */ }
visited[decl ? visited.length - 1 : i].r.add(val)
} else if (op.o !== O.fn) {
if (0) { op.o satisfies O.block | O.stat } // lgtm [js/unreachable-statement]
const varNames = op.o === O.block ? op.v.c ? op.v.l ? op.v.c.concat(op.v.l) : op.v.c : op.v.l!
: op.v.a === "catch" ? [VarName(op.v.c!.v)]
: (((op.v.c as Extract<BaseStatement<"for">["c"], BaseOp<O.comma>>
).v[0].v as SomeStatements<VarActions>).v.v satisfies (RefOp | RefAssignOp)[] as (RefOp | RefAssignOp)[]
).map(ToVarName)
enter ? visited.push({ d: varNames, r: Set2() }) : visited.pop()
} else if (enter) {
const fn: OpValues[O.fn] = op.v
if (fn.b.o === O.block && !fn.v) { prepareBlockBodyToRun(fn.v = [], fn.b.v) }
visited.push({ d: 0, r: Set2() })
const args = fn.a.map(ToVarName)
fn.t.length > 3 && args.push(VarName(fn.n!))
args.length && visited.push({ d: args, r: Set2() })
} else {
const frame = visited.pop()!, set = (frame.d ? visited.pop()! : frame).r
const op2: RefOp = Op(O.token, "a" as unknown as VarLiterals),
ref = Build.MV3 || !(Build.BTypes & BrowserType.Chrome) || Build.MinCVer >= BrowserVer.MinTestedES6Environment
? [...set satisfies Set2<VarNames> as unknown as VarNames[]]
: kHasSet ? Array.from(set as unknown as VarNames[]) : (set as unknown as VarNames[]).slice()
; (op.v.r satisfies OpValues[O.fn]["r"]) = ref
for (const i of ref) {
_collect!(op2, i)
}
}
}
ToString(func, 0)
_collect = null
}

//#endregion parse syntax tree

//#region evaluate
Expand Down Expand Up @@ -614,8 +664,15 @@ const StackFrame = (block: OpValues[O.block], args?: readonly [VarLiterals, unkn
}

const exitFrame = (): void => {
const frame: StackFrame = locals_.pop()!
const frame: StackFrame = locals_.pop()!, { r: inClosure, v: ref } = frame
frame.r = 0
if (inClosure === 1) {
(frame.v as StackFrame["v"]) = Object.create(null), (frame.c as StackFrame["c"]) = []
} else {
for (var key in ref) {
(inClosure as Exclude<typeof inClosure, 0>).has(key as (keyof typeof ref) & string) || delete ref[key]
}
}
}

const _resolveVarRef = (name: VarLiterals, getter: R): Ref => {
Expand Down Expand Up @@ -666,7 +723,7 @@ const evalTry = (stats: readonly Statement[], i: number): [unknown, number] => {
else try { res = evalBlockBody(statement.v.v); done = 1 }
catch (ex) {
g_exc || newException()
locals_.length = oldLocalsPos
while (locals_.length > oldLocalsPos) { exitFrame() }
next.c && StackFrame(next.v.v, [[next.c.v, ex]])
i++; res = evalBlockBody(next.c ? { c: 0, l: 0, x: next.v.v.x } : next.v.v)
next.c && exitFrame(); g_exc = null; done = 1
Expand Down Expand Up @@ -697,10 +754,10 @@ const evalFor = (statement: BaseStatement<"for">): unknown => {
const varStat = initOp && initOp.v.a ? initOp.v as SomeStatements<VarActions> : null
const newScope = !!varStat && varStat.a !== "var"
const forkScope = (): VarDict => {
const old = locals_[locals_.length - 1], newVars: VarDict = Object.create(null), oldVars = old.v
const old = locals_[locals_.length - 1], newVars: VarDict = Object.create(null), { v: oldVars, c, n, r } = old
for (let key in oldVars) { newVars[key as VarNames] = oldVars[key as VarNames] }
exitFrame()
locals_.push({ v: newVars, c: old.c, n: old.n, r: 1 })
locals_.push({ v: newVars, c, n, r })
return newVars
}
let res: unknown = kFakeValue, ref: Writable<Ref>
Expand Down Expand Up @@ -1012,7 +1069,8 @@ const FunctionFromOp = (fn: OpValues[O.fn], globals: Isolate, closures: StackFra
&& Build.MinCVer < BrowserVer.MinEnsuredES6NewTarget ? this instanceof callable : new.target
if (isNew && fn.t < "f") { throwType((stdName || "anonymous") + "is not a constructor") }
isolate_ = globals, locals_ = closures.slice(), g_exc = g_exc && g_exc.d < 0 ? g_exc : null
const selfRefFrame = fn.t.length > 3 && !!StackFrame({ c: [VarName(fn.n!)], l: 0, x: [] }, [[fn.n!, callable]])
const oldLocalsPos = locals_.length
fn.t.length > 3 && StackFrame({ c: [VarName(fn.n!)], l: 0, x: [] }, [[fn.n!, callable]])
if (fn.b.o === O.block && !fn.v) { prepareBlockBodyToRun(fn.v = [], fn.b.v) }
++stackDepth_
try {
Expand All @@ -1033,8 +1091,7 @@ const FunctionFromOp = (fn: OpValues[O.fn], globals: Isolate, closures: StackFra
stackDepth_--
!Build.NDEBUG && done && (frame && locals_[locals_.length - 1] !== frame)
&& console.log("Vimium C found a bug of stack error when calling `" + (stdName || "anonymous") + "(...)`")
frame && exitFrame()
selfRefFrame && exitFrame()
while (locals_.length > oldLocalsPos) { exitFrame() }
isolate_ = oldIsolate, locals_ = oldLocals
}
}
Expand All @@ -1048,6 +1105,26 @@ const FunctionFromOp = (fn: OpValues[O.fn], globals: Isolate, closures: StackFra
})
closures = closures.slice()
if (!topMost) {
fn.r || analyseEscaped(Op(O.fn, fn))
const kUseSet = !(Build.BTypes & BrowserType.Chrome) || Build.MinCVer >= BrowserVer.MinTestedES6Environment
const arr = kUseSet ? new Set!<VarNames>(fn.r!) : fn.r!.slice()
for (let i = locals_.length; 0 <= --i && (kUseSet ? (<Set<VarNames>> arr).size : (<VarNames[]> arr).length) > 0; ) {
let inClosure = locals_[i].r
if (inClosure === 0) { break }
const vars = locals_[i].v
if (kUseSet) {
for (const r of arr as Set<VarNames> as unknown as VarNames[]) {
r in vars && ((arr as Set<VarNames>).delete(r)
, (inClosure = inClosure !== 1 ? inClosure : (locals_[i].r = Set2())).add(r))
}
} else {
for (let i = (arr as VarNames[]).length; 0 <= --i; ) {
const r = (arr as VarNames[])[i]
r in vars && ((arr as VarNames[]).splice(i, 1)
, (inClosure = inClosure !== 1 ? inClosure : (locals_[i].r = Set2())).add(r))
}
}
}
}
return callable
}
Expand Down Expand Up @@ -1076,21 +1153,28 @@ const ToString = (op: Op, allowed: number): string => {
let arr: string[]
switch (op.o) {
case O.block: case O.statGroup: /* O.block | O.statGroup: */
const doesCollect1 = !!_collect && op.o === O.block && !!(op.v.c || op.v.l)
arr = []
doesCollect1 && _collect!(op, 1)
for (const stat of op.o === O.block ? op.v.x : op.v) {
let str = ToString(Op(O.stat, stat), allowed && (allowed | 1 << O.block | 1 << O.statGroup | 1 << O.stat))
arr.push(str)
}
doesCollect1 && _collect!(op, 0)
return arr.length > 0 ? op.o === O.statGroup ? arr.join("\n") : "{\n" + indent(arr.join("\n")) + "\n}" : "{ }"
case O.stat: /* O.stat: */ {
const { a: prefix, c: clause, l: label } = op.v, child = op.v.v
const doesCollect2 = !!_collect && (prefix === "catch" ? !!clause
: prefix === "for" && (clause.o === O.comma && clause.v[0].v.a && clause.v[0].v.a !== "var"))
doesCollect2 && _collect!(op, 1)
const c = !clause ? "" : prefix !== "for" || clause.o !== O.comma ? ToString(clause, allowed)
: clause.v.length === 1 ? ToString(clause.v[0], allowed)
: (clause.v[0].v.v.o === O.comma && (clause.v[0].v.v as BaseOp<O.comma>).v.length === 0 ? " ;"
: ToString(clause.v[0], allowed) || (kUnknown + ";")) + " "
+ (ToString(clause.v[1], allowed) || kUnknown).trim() + "; "
+ (ToString(clause.v[2], allowed) || kUnknown).trim()
let x = child ? ToString(child, allowed) : ""
doesCollect2 && _collect!(op, 0)
return (label ? label.slice(1).map(i => i + ":\n").join("") + label[0] + ": " : "")
+ prefix + (clause ? c ? ` (${c})` : " " + kUnknown : "")
+ (!child ? "" : !x ? child.o !== O.block ? " " + kUnknown + ";" : " { ... }"
Expand Down Expand Up @@ -1120,9 +1204,11 @@ const ToString = (op: Op, allowed: number): string => {
: " " + ToString(Op(O.fn, op.v.v.v), allowed && (allowed | (1 << O.fn))))
case O.fn: /* O.fn: */ {
if (op.v.p && op.v.p.v.v === op) { return ToString(op.v.p, allowed && (allowed | (1 << O.pair) | (1 << O.token))) }
_collect && _collect(op, 1)
const argsList = !op.v.a.length ? ""
: ToString(Op(O.comma, op.v.a), allowed && (allowed | (1 << O.comma | 1 << O.token | 1 << O.assign)))
const body = ToWrapped(op, allowed && op.v.b.o === O.block ? (allowed | 1 << O.block) : allowed, op.v.b)
_collect && _collect(op, 0)
return (op.v.t > "f" ? "function " + op.v.n + "(" : "(")
+ (argsList.includes("\n") ? argsList + "\n" : argsList)
+ (op.v.t !== "=>" ? ") " + body : op.v.b.o !== O.block && body.includes("\n") ? ") =>\n" + indent(body)
Expand Down Expand Up @@ -1161,6 +1247,7 @@ const ToString = (op: Op, allowed: number): string => {
+ (op.v.b === "{" ? " }" : " ]")
case O.token: /* O.token: */ {
const isRef = typeof op.v === "string", val = isRef ? op.v : op.v.v
isRef && _collect && _collect(op as RefOp, VarName((op as RefOp).v))
return isRef ? val as RefOp["v"] : typeof val === "string" ? JSON.stringify(val) : val === kFakeValue ? " "
: typeof val === "bigint" ? val + "n" : !val || typeof val !== "object" ? val + ""
: val.c === 4 ? `/${val.v[0]}/${val.v[1]}` : val.v + ""
Expand Down

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