[torque] introduce separate implicit parameters for JavaScript calling convention

Implicit parameters for builtins with JavaScript linkage are now separate, using
the keyword "js-implicit". They have to be one of:
- context: Context
- receiver: Object (this in JS)
- target: JSFunction (arguments.callee in JS)
- newTarget: Object (new.target in JS)

Bug: v8:9120 v8:7793

Change-Id: I916f60971bb53d5046b6006725d0ce39291ca55e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1658159Reviewed-by: Tamer Tas <tmrts@chromium.org>
Reviewed-by: Simon Zünd <szuend@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62174}

src/builtins/array-copywithin.tq

@@ -9,7 +9,7 @@ namespace array_copywithin {
 
   // https://tc39.github.io/ecma262/#sec-array.prototype.copyWithin
   transitioning javascript builtin ArrayPrototypeCopyWithin(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     // 1. Let O be ? ToObject(this value).
     const object: JSReceiver = ToObject_Inline(context, receiver);
 

src/builtins/array-every.tq

@@ -4,8 +4,9 @@
 
 namespace array {
   transitioning javascript builtin
-  ArrayEveryLoopEagerDeoptContinuation(implicit context: Context)(
-      receiver: Object, callback: Object, thisArg: Object, initialK: Object,
+  ArrayEveryLoopEagerDeoptContinuation(
+      js-implicit context: Context, receiver: Object)(
+      callback: Object, thisArg: Object, initialK: Object,
       length: Object): Object {
     // All continuation points in the optimized every implementation are
     // after the ToObject(O) call that ensures we are dealing with a
@@ -25,9 +26,10 @@ namespace array {
   }
 
   transitioning javascript builtin
-  ArrayEveryLoopLazyDeoptContinuation(implicit context: Context)(
-      receiver: Object, callback: Object, thisArg: Object, initialK: Object,
-      length: Object, result: Object): Object {
+  ArrayEveryLoopLazyDeoptContinuation(
+      js-implicit context: Context, receiver: Object)(
+      callback: Object, thisArg: Object, initialK: Object, length: Object,
+      result: Object): Object {
     // All continuation points in the optimized every implementation are
     // after the ToObject(O) call that ensures we are dealing with a
     // JSReceiver.
@@ -109,7 +111,7 @@ namespace array {
 
   // https://tc39.github.io/ecma262/#sec-array.prototype.every
   transitioning javascript builtin
-  ArrayEvery(implicit context: Context)(receiver: Object, ...arguments):
+  ArrayEvery(js-implicit context: Context, receiver: Object)(...arguments):
       Object {
     try {
       if (IsNullOrUndefined(receiver)) {

src/builtins/array-filter.tq

@@ -4,9 +4,10 @@
 
 namespace array_filter {
   transitioning javascript builtin
-  ArrayFilterLoopEagerDeoptContinuation(implicit context: Context)(
-      receiver: Object, callback: Object, thisArg: Object, array: Object,
-      initialK: Object, length: Object, initialTo: Object): Object {
+  ArrayFilterLoopEagerDeoptContinuation(
+      js-implicit context: Context, receiver: Object)(
+      callback: Object, thisArg: Object, array: Object, initialK: Object,
+      length: Object, initialTo: Object): Object {
     // All continuation points in the optimized filter implementation are
     // after the ToObject(O) call that ensures we are dealing with a
     // JSReceiver.
@@ -27,9 +28,10 @@ namespace array_filter {
   }
 
   transitioning javascript builtin
-  ArrayFilterLoopLazyDeoptContinuation(implicit context: Context)(
-      receiver: Object, callback: Object, thisArg: Object, array: Object,
-      initialK: Object, length: Object, valueK: Object, initialTo: Object,
+  ArrayFilterLoopLazyDeoptContinuation(
+      js-implicit context: Context, receiver: Object)(
+      callback: Object, thisArg: Object, array: Object, initialK: Object,
+      length: Object, valueK: Object, initialTo: Object,
       result: Object): Object {
     // All continuation points in the optimized filter implementation are
     // after the ToObject(O) call that ensures we are dealing with a
@@ -42,9 +44,9 @@ namespace array_filter {
     const numberLength = Cast<Number>(length) otherwise unreachable;
 
     // This custom lazy deopt point is right after the callback. filter() needs
-    // to pick up at the next step, which is setting the callback result in
-    // the output array. After incrementing k and to, we can glide into the loop
-    // continuation builtin.
+    // to pick up at the next step, which is setting the callback
+    // result in the output array. After incrementing k and to, we can glide
+    // into the loop continuation builtin.
     if (ToBoolean(result)) {
       FastCreateDataProperty(outputArray, numberTo, valueK);
       numberTo = numberTo + 1;
@@ -145,7 +147,7 @@ namespace array_filter {
 
   // https://tc39.github.io/ecma262/#sec-array.prototype.filter
   transitioning javascript builtin
-  ArrayFilter(implicit context: Context)(receiver: Object, ...arguments):
+  ArrayFilter(js-implicit context: Context, receiver: Object)(...arguments):
       Object {
     try {
       if (IsNullOrUndefined(receiver)) {

src/builtins/array-find.tq

@@ -4,8 +4,9 @@
 
 namespace array_find {
   transitioning javascript builtin
-  ArrayFindLoopEagerDeoptContinuation(implicit context: Context)(
-      receiver: Object, callback: Object, thisArg: Object, initialK: Object,
+  ArrayFindLoopEagerDeoptContinuation(
+      js-implicit context: Context, receiver: Object)(
+      callback: Object, thisArg: Object, initialK: Object,
       length: Object): Object {
     // All continuation points in the optimized find implementation are
     // after the ToObject(O) call that ensures we are dealing with a
@@ -24,9 +25,10 @@ namespace array_find {
   }
 
   transitioning javascript builtin
-  ArrayFindLoopLazyDeoptContinuation(implicit context: Context)(
-      _receiver: Object, _callback: Object, _thisArg: Object, _initialK: Object,
-      _length: Object, _result: Object): Object {
+  ArrayFindLoopLazyDeoptContinuation(
+      js-implicit context: Context, receiver: Object)(
+      _callback: Object, _thisArg: Object, _initialK: Object, _length: Object,
+      _result: Object): Object {
     // This deopt continuation point is never actually called, it just
     // exists to make stack traces correct from a ThrowTypeError if the
     // callback was found to be non-callable.
@@ -37,9 +39,10 @@ namespace array_find {
   // happens right after the callback and it's returned value must be handled
   // before iteration continues.
   transitioning javascript builtin
-  ArrayFindLoopAfterCallbackLazyDeoptContinuation(implicit context: Context)(
-      receiver: Object, callback: Object, thisArg: Object, initialK: Object,
-      length: Object, foundValue: Object, isFound: Object): Object {
+  ArrayFindLoopAfterCallbackLazyDeoptContinuation(
+      js-implicit context: Context, receiver: Object)(
+      callback: Object, thisArg: Object, initialK: Object, length: Object,
+      foundValue: Object, isFound: Object): Object {
     // All continuation points in the optimized find implementation are
     // after the ToObject(O) call that ensures we are dealing with a
     // JSReceiver.
@@ -116,8 +119,8 @@ namespace array_find {
 
   // https://tc39.github.io/ecma262/#sec-array.prototype.find
   transitioning javascript builtin
-  ArrayPrototypeFind(implicit context: Context)(receiver: Object, ...arguments):
-      Object {
+  ArrayPrototypeFind(js-implicit context: Context, receiver: Object)(
+      ...arguments): Object {
     try {
       if (IsNullOrUndefined(receiver)) {
         goto NullOrUndefinedError;

src/builtins/array-findindex.tq

@@ -4,8 +4,9 @@
 
 namespace array_findindex {
   transitioning javascript builtin
-  ArrayFindIndexLoopEagerDeoptContinuation(implicit context: Context)(
-      receiver: Object, callback: Object, thisArg: Object, initialK: Object,
+  ArrayFindIndexLoopEagerDeoptContinuation(
+      js-implicit context: Context, receiver: Object)(
+      callback: Object, thisArg: Object, initialK: Object,
       length: Object): Object {
     // All continuation points in the optimized findIndex implementation are
     // after the ToObject(O) call that ensures we are dealing with a
@@ -24,9 +25,10 @@ namespace array_findindex {
   }
 
   transitioning javascript builtin
-  ArrayFindIndexLoopLazyDeoptContinuation(implicit context: Context)(
-      _receiver: Object, _callback: Object, _thisArg: Object, _initialK: Object,
-      _length: Object, _result: Object): Object {
+  ArrayFindIndexLoopLazyDeoptContinuation(
+      js-implicit context: Context, receiver: Object)(
+      _callback: Object, _thisArg: Object, _initialK: Object, _length: Object,
+      _result: Object): Object {
     // This deopt continuation point is never actually called, it just
     // exists to make stack traces correct from a ThrowTypeError if the
     // callback was found to be non-callable.
@@ -37,10 +39,10 @@ namespace array_findindex {
   // happens right after the callback and it's returned value must be handled
   // before iteration continues.
   transitioning javascript builtin
-  ArrayFindIndexLoopAfterCallbackLazyDeoptContinuation(implicit context:
-                                                           Context)(
-      receiver: Object, callback: Object, thisArg: Object, initialK: Object,
-      length: Object, foundValue: Object, isFound: Object): Object {
+  ArrayFindIndexLoopAfterCallbackLazyDeoptContinuation(
+      js-implicit context: Context, receiver: Object)(
+      callback: Object, thisArg: Object, initialK: Object, length: Object,
+      foundValue: Object, isFound: Object): Object {
     // All continuation points in the optimized findIndex implementation are
     // after the ToObject(O) call that ensures we are dealing with a
     // JSReceiver.
@@ -118,8 +120,8 @@ namespace array_findindex {
 
   // https://tc39.github.io/ecma262/#sec-array.prototype.findIndex
   transitioning javascript builtin
-  ArrayPrototypeFindIndex(implicit context:
-                              Context)(receiver: Object, ...arguments): Object {
+  ArrayPrototypeFindIndex(js-implicit context: Context, receiver: Object)(
+      ...arguments): Object {
     try {
       if (IsNullOrUndefined(receiver)) {
         goto NullOrUndefinedError;

src/builtins/array-foreach.tq

@@ -4,8 +4,9 @@
 
 namespace array_foreach {
   transitioning javascript builtin
-  ArrayForEachLoopEagerDeoptContinuation(implicit context: Context)(
-      receiver: Object, callback: Object, thisArg: Object, initialK: Object,
+  ArrayForEachLoopEagerDeoptContinuation(
+      js-implicit context: Context, receiver: Object)(
+      callback: Object, thisArg: Object, initialK: Object,
       length: Object): Object {
     // All continuation points in the optimized forEach implemntation are
     // after the ToObject(O) call that ensures we are dealing with a
@@ -21,9 +22,10 @@ namespace array_foreach {
   }
 
   transitioning javascript builtin
-  ArrayForEachLoopLazyDeoptContinuation(implicit context: Context)(
-      receiver: Object, callback: Object, thisArg: Object, initialK: Object,
-      length: Object, _result: Object): Object {
+  ArrayForEachLoopLazyDeoptContinuation(
+      js-implicit context: Context, receiver: Object)(
+      callback: Object, thisArg: Object, initialK: Object, length: Object,
+      _result: Object): Object {
     // All continuation points in the optimized forEach implemntation are
     // after the ToObject(O) call that ensures we are dealing with a
     // JSReceiver.
@@ -90,7 +92,8 @@ namespace array_foreach {
 
   // https://tc39.github.io/ecma262/#sec-array.prototype.foreach
   transitioning javascript builtin
-  ArrayForEach(context: Context, receiver: Object, ...arguments): Object {
+  ArrayForEach(js-implicit context: Context, receiver: Object)(...arguments):
+      Object {
     try {
       if (IsNullOrUndefined(receiver)) {
         goto NullOrUndefinedError;

src/builtins/array-join.tq

@@ -557,7 +557,8 @@ namespace array_join {
 
   // https://tc39.github.io/ecma262/#sec-array.prototype.join
   transitioning javascript builtin
-  ArrayPrototypeJoin(context: Context, receiver: Object, ...arguments): Object {
+  ArrayPrototypeJoin(js-implicit context: Context, receiver: Object)(
+      ...arguments): Object {
     const separator: Object = arguments[0];
 
     // 1. Let O be ? ToObject(this value).
@@ -566,8 +567,8 @@ namespace array_join {
     // 2. Let len be ? ToLength(? Get(O, "length")).
     const len: Number = GetLengthProperty(o);
 
-    // Only handle valid array lengths. Although the spec allows larger values,
-    // this matches historical V8 behavior.
+    // Only handle valid array lengths. Although the spec allows larger
+    // values, this matches historical V8 behavior.
     if (len > kMaxArrayIndex + 1) ThrowTypeError(kInvalidArrayLength);
 
     return CycleProtectedArrayJoin<JSArray>(
@@ -576,7 +577,7 @@ namespace array_join {
 
   // https://tc39.github.io/ecma262/#sec-array.prototype.tolocalestring
   transitioning javascript builtin ArrayPrototypeToLocaleString(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     const locales: Object = arguments[0];
     const options: Object = arguments[1];
 
@@ -586,8 +587,8 @@ namespace array_join {
     // 2. Let len be ? ToLength(? Get(O, "length")).
     const len: Number = GetLengthProperty(o);
 
-    // Only handle valid array lengths. Although the spec allows larger values,
-    // this matches historical V8 behavior.
+    // Only handle valid array lengths. Although the spec allows larger
+    // values, this matches historical V8 behavior.
     if (len > kMaxArrayIndex + 1) ThrowTypeError(kInvalidArrayLength);
 
     return CycleProtectedArrayJoin<JSArray>(
@@ -596,7 +597,7 @@ namespace array_join {
 
   // https://tc39.github.io/ecma262/#sec-array.prototype.tostring
   transitioning javascript builtin ArrayPrototypeToString(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     // 1. Let array be ? ToObject(this value).
     const array: JSReceiver = ToObject_Inline(context, receiver);
 
@@ -617,7 +618,7 @@ namespace array_join {
 
   // https://tc39.github.io/ecma262/#sec-%typedarray%.prototype.join
   transitioning javascript builtin TypedArrayPrototypeJoin(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     const separator: Object = arguments[0];
 
     // Spec: ValidateTypedArray is applied to the this value prior to evaluating
@@ -632,7 +633,7 @@ namespace array_join {
 
   // https://tc39.github.io/ecma262/#sec-%typedarray%.prototype.tolocalestring
   transitioning javascript builtin TypedArrayPrototypeToLocaleString(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     const locales: Object = arguments[0];
     const options: Object = arguments[1];
 

src/builtins/array-lastindexof.tq

@@ -131,7 +131,7 @@ namespace array_lastindexof {
 
   // https://tc39.github.io/ecma262/#sec-array.prototype.lastIndexOf
   transitioning javascript builtin ArrayPrototypeLastIndexOf(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     // 1. Let O be ? ToObject(this value).
     const object: JSReceiver = ToObject_Inline(context, receiver);
 

src/builtins/array-map.tq

@@ -4,9 +4,10 @@
 
 namespace array_map {
   transitioning javascript builtin
-  ArrayMapLoopEagerDeoptContinuation(implicit context: Context)(
-      receiver: Object, callback: Object, thisArg: Object, array: Object,
-      initialK: Object, length: Object): Object {
+  ArrayMapLoopEagerDeoptContinuation(
+      js-implicit context: Context, receiver: Object)(
+      callback: Object, thisArg: Object, array: Object, initialK: Object,
+      length: Object): Object {
     // All continuation points in the optimized filter implementation are
     // after the ToObject(O) call that ensures we are dealing with a
     // JSReceiver.
@@ -26,9 +27,10 @@ namespace array_map {
   }
 
   transitioning javascript builtin
-  ArrayMapLoopLazyDeoptContinuation(implicit context: Context)(
-      receiver: Object, callback: Object, thisArg: Object, array: Object,
-      initialK: Object, length: Object, result: Object): Object {
+  ArrayMapLoopLazyDeoptContinuation(
+      js-implicit context: Context, receiver: Object)(
+      callback: Object, thisArg: Object, array: Object, initialK: Object,
+      length: Object, result: Object): Object {
     // All continuation points in the optimized filter implementation are
     // after the ToObject(O) call that ensures we are dealing with a
     // JSReceiver.
@@ -222,7 +224,8 @@ namespace array_map {
 
   // https://tc39.github.io/ecma262/#sec-array.prototype.map
   transitioning javascript builtin
-  ArrayMap(implicit context: Context)(receiver: Object, ...arguments): Object {
+  ArrayMap(js-implicit context: Context, receiver: Object)(...arguments):
+      Object {
     try {
       if (IsNullOrUndefined(receiver)) goto NullOrUndefinedError;
 

src/builtins/array-of.tq

@@ -5,7 +5,8 @@
 namespace array_of {
   // https://tc39.github.io/ecma262/#sec-array.of
   transitioning javascript builtin
-  ArrayOf(implicit context: Context)(receiver: Object, ...arguments): Object {
+  ArrayOf(js-implicit context: Context, receiver: Object)(...arguments):
+      Object {
     // 1. Let len be the actual number of arguments passed to this function.
     const len: Smi = Convert<Smi>(arguments.length);
 

src/builtins/array-reduce-right.tq

@@ -4,8 +4,9 @@
 
 namespace array {
   transitioning javascript builtin
-  ArrayReduceRightPreLoopEagerDeoptContinuation(implicit context: Context)(
-      receiver: Object, callback: Object, length: Object): Object {
+  ArrayReduceRightPreLoopEagerDeoptContinuation(
+      js-implicit context: Context,
+      receiver: Object)(callback: Object, length: Object): Object {
     // All continuation points in the optimized every implementation are
     // after the ToObject(O) call that ensures we are dealing with a
     // JSReceiver.
@@ -25,8 +26,9 @@ namespace array {
   }
 
   transitioning javascript builtin
-  ArrayReduceRightLoopEagerDeoptContinuation(implicit context: Context)(
-      receiver: Object, callback: Object, initialK: Object, length: Object,
+  ArrayReduceRightLoopEagerDeoptContinuation(
+      js-implicit context: Context, receiver: Object)(
+      callback: Object, initialK: Object, length: Object,
       accumulator: Object): Object {
     // All continuation points in the optimized every implementation are
     // after the ToObject(O) call that ensures we are dealing with a
@@ -45,8 +47,9 @@ namespace array {
   }
 
   transitioning javascript builtin
-  ArrayReduceRightLoopLazyDeoptContinuation(implicit context: Context)(
-      receiver: Object, callback: Object, initialK: Object, length: Object,
+  ArrayReduceRightLoopLazyDeoptContinuation(
+      js-implicit context: Context, receiver: Object)(
+      callback: Object, initialK: Object, length: Object,
       result: Object): Object {
     // All continuation points in the optimized every implementation are
     // after the ToObject(O) call that ensures we are dealing with a
@@ -139,8 +142,8 @@ namespace array {
 
   // https://tc39.github.io/ecma262/#sec-array.prototype.reduceRight
   transitioning javascript builtin
-  ArrayReduceRight(implicit context: Context)(receiver: Object, ...arguments):
-      Object {
+  ArrayReduceRight(js-implicit context: Context, receiver: Object)(
+      ...arguments): Object {
     try {
       if (IsNullOrUndefined(receiver)) {
         goto NullOrUndefinedError;

src/builtins/array-reduce.tq

@@ -4,8 +4,9 @@
 
 namespace array {
   transitioning javascript builtin
-  ArrayReducePreLoopEagerDeoptContinuation(implicit context: Context)(
-      receiver: Object, callback: Object, length: Object): Object {
+  ArrayReducePreLoopEagerDeoptContinuation(
+      js-implicit context: Context,
+      receiver: Object)(callback: Object, length: Object): Object {
     // All continuation points in the optimized every implementation are
     // after the ToObject(O) call that ensures we are dealing with a
     // JSReceiver.
@@ -25,8 +26,9 @@ namespace array {
   }
 
   transitioning javascript builtin
-  ArrayReduceLoopEagerDeoptContinuation(implicit context: Context)(
-      receiver: Object, callback: Object, initialK: Object, length: Object,
+  ArrayReduceLoopEagerDeoptContinuation(
+      js-implicit context: Context, receiver: Object)(
+      callback: Object, initialK: Object, length: Object,
       accumulator: Object): Object {
     // All continuation points in the optimized every implementation are
     // after the ToObject(O) call that ensures we are dealing with a
@@ -45,8 +47,9 @@ namespace array {
   }
 
   transitioning javascript builtin
-  ArrayReduceLoopLazyDeoptContinuation(implicit context: Context)(
-      receiver: Object, callback: Object, initialK: Object, length: Object,
+  ArrayReduceLoopLazyDeoptContinuation(
+      js-implicit context: Context, receiver: Object)(
+      callback: Object, initialK: Object, length: Object,
       result: Object): Object {
     // All continuation points in the optimized every implementation are
     // after the ToObject(O) call that ensures we are dealing with a
@@ -139,7 +142,7 @@ namespace array {
 
   // https://tc39.github.io/ecma262/#sec-array.prototype.reduce
   transitioning javascript builtin
-  ArrayReduce(implicit context: Context)(receiver: Object, ...arguments):
+  ArrayReduce(js-implicit context: Context, receiver: Object)(...arguments):
       Object {
     try {
       if (IsNullOrUndefined(receiver)) {

src/builtins/array-reverse.tq

@@ -165,7 +165,7 @@ namespace array_reverse {
 
   // https://tc39.github.io/ecma262/#sec-array.prototype.reverse
   transitioning javascript builtin ArrayPrototypeReverse(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     try {
       TryFastPackedArrayReverse(receiver) otherwise Baseline;
       return receiver;

src/builtins/array-shift.tq

@@ -103,7 +103,7 @@ namespace array_shift {
 
   // https://tc39.github.io/ecma262/#sec-array.prototype.shift
   transitioning javascript builtin ArrayPrototypeShift(
-      implicit context: Context)(receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     try {
       return TryFastArrayShift(receiver, arguments) otherwise Slow;
     }

src/builtins/array-slice.tq

@@ -122,8 +122,8 @@ namespace array_slice {
 
   // https://tc39.github.io/ecma262/#sec-array.prototype.slice
   transitioning javascript builtin
-  ArrayPrototypeSlice(context: Context, receiver: Object, ...arguments):
-      Object {
+  ArrayPrototypeSlice(js-implicit context: Context, receiver: Object)(
+      ...arguments): Object {
     // Handle array cloning case if the receiver is a fast array.
     if (arguments.length == 0) {
       typeswitch (receiver) {

src/builtins/array-some.tq

@@ -4,8 +4,9 @@
 
 namespace array {
   transitioning javascript builtin
-  ArraySomeLoopEagerDeoptContinuation(implicit context: Context)(
-      receiver: Object, callback: Object, thisArg: Object, initialK: Object,
+  ArraySomeLoopEagerDeoptContinuation(
+      js-implicit context: Context, receiver: Object)(
+      callback: Object, thisArg: Object, initialK: Object,
       length: Object): Object {
     // All continuation points in the optimized some implementation are
     // after the ToObject(O) call that ensures we are dealing with a
@@ -25,9 +26,10 @@ namespace array {
   }
 
   transitioning javascript builtin
-  ArraySomeLoopLazyDeoptContinuation(implicit context: Context)(
-      receiver: Object, callback: Object, thisArg: Object, initialK: Object,
-      length: Object, result: Object): Object {
+  ArraySomeLoopLazyDeoptContinuation(
+      js-implicit context: Context, receiver: Object)(
+      callback: Object, thisArg: Object, initialK: Object, length: Object,
+      result: Object): Object {
     // All continuation points in the optimized some implementation are
     // after the ToObject(O) call that ensures we are dealing with a
     // JSReceiver.
@@ -109,7 +111,8 @@ namespace array {
 
   // https://tc39.github.io/ecma262/#sec-array.prototype.some
   transitioning javascript builtin
-  ArraySome(implicit context: Context)(receiver: Object, ...arguments): Object {
+  ArraySome(js-implicit context: Context, receiver: Object)(...arguments):
+      Object {
     try {
       if (IsNullOrUndefined(receiver)) {
         goto NullOrUndefinedError;

src/builtins/array-splice.tq

@@ -350,8 +350,8 @@ namespace array_splice {
 
   // https://tc39.github.io/ecma262/#sec-array.prototype.splice
   transitioning javascript builtin
-  ArrayPrototypeSplice(context: Context, receiver: Object, ...arguments):
-      Object {
+  ArrayPrototypeSplice(js-implicit context: Context, receiver: Object)(
+      ...arguments): Object {
     // 1. Let O be ? ToObject(this value).
     const o: JSReceiver = ToObject(context, receiver);
 

src/builtins/array-unshift.tq

@@ -93,7 +93,7 @@ namespace array_unshift {
 
   // https://tc39.github.io/ecma262/#sec-array.prototype.unshift
   transitioning javascript builtin ArrayPrototypeUnshift(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     try {
       TryFastArrayUnshift(context, receiver, arguments) otherwise Baseline;
     }

src/builtins/boolean.tq

@@ -3,24 +3,16 @@
 // found in the LICENSE file.
 
 namespace boolean {
-  // TODO(v8:9120): This is a workaround to get access to target and new.target
-  // in javascript builtins. Requires cleanup once this is fully supported by
-  // torque.
-  const NEW_TARGET_INDEX:
-      constexpr int32 generates 'Descriptor::kJSNewTarget';
-  const TARGET_INDEX: constexpr int32 generates 'Descriptor::kJSTarget';
-  extern macro Parameter(constexpr int32): Object;
-
   javascript builtin
-  BooleanConstructor(context: Context, receiver: Object, ...arguments): Object {
+  BooleanConstructor(
+      js-implicit context: Context, receiver: Object, newTarget: Object,
+      target: JSFunction)(...arguments): Object {
     const value = SelectBooleanConstant(ToBoolean(arguments[0]));
 
-    const newTarget = Parameter(NEW_TARGET_INDEX);
     if (newTarget == Undefined) {
       return value;
     }
 
-    const target = UnsafeCast<JSFunction>(Parameter(TARGET_INDEX));
     const map = GetDerivedMap(target, UnsafeCast<JSReceiver>(newTarget));
 
     const obj = UnsafeCast<JSValue>(AllocateFastOrSlowJSObjectFromMap(map));

src/builtins/builtins-proxy-gen.cc

@@ -136,11 +136,6 @@ Node* ProxiesCodeStubAssembler::AllocateProxyRevokeFunction(Node* proxy,
                                            proxy_context);
 }
 
-Node* ProxiesCodeStubAssembler::GetProxyConstructorJSNewTarget() {
-  return CodeAssembler::Parameter(static_cast<int>(
-      Builtin_ProxyConstructor_InterfaceDescriptor::kJSNewTarget));
-}
-
 TF_BUILTIN(CallProxy, ProxiesCodeStubAssembler) {
   Node* argc = Parameter(Descriptor::kActualArgumentsCount);
   Node* argc_ptr = ChangeInt32ToIntPtr(argc);

src/builtins/builtins-proxy-gen.h

@@ -20,10 +20,6 @@ class ProxiesCodeStubAssembler : public CodeStubAssembler {
   Node* AllocateProxy(Node* target, Node* handler, Node* context);
   Node* AllocateProxyRevokeFunction(Node* proxy, Node* context);
 
-  // Get JSNewTarget parameter for ProxyConstructor builtin (Torque).
-  // TODO(v8:9120): Remove this once torque support exists
-  Node* GetProxyConstructorJSNewTarget();
-
   Node* CheckGetSetTrapResult(Node* context, Node* target, Node* proxy,
                               Node* name, Node* trap_result,
                               JSProxy::AccessKind access_kind);

src/builtins/data-view.tq

@@ -74,7 +74,8 @@ namespace data_view {
 
   // ES6 section 24.2.4.1 get DataView.prototype.buffer
   javascript builtin DataViewPrototypeGetBuffer(
-      context: Context, receiver: Object, ...arguments): JSArrayBuffer {
+      js-implicit context: Context,
+      receiver: Object)(...arguments): JSArrayBuffer {
     const dataView: JSDataView =
         ValidateDataView(context, receiver, 'get DataView.prototype.buffer');
     return dataView.buffer;
@@ -82,7 +83,7 @@ namespace data_view {
 
   // ES6 section 24.2.4.2 get DataView.prototype.byteLength
   javascript builtin DataViewPrototypeGetByteLength(
-      context: Context, receiver: Object, ...arguments): Number {
+      js-implicit context: Context, receiver: Object)(...arguments): Number {
     const dataView: JSDataView = ValidateDataView(
         context, receiver, 'get DataView.prototype.byte_length');
     if (WasNeutered(dataView)) {
@@ -95,7 +96,7 @@ namespace data_view {
 
   // ES6 section 24.2.4.3 get DataView.prototype.byteOffset
   javascript builtin DataViewPrototypeGetByteOffset(
-      context: Context, receiver: Object, ...arguments): Number {
+      js-implicit context: Context, receiver: Object)(...arguments): Number {
     const dataView: JSDataView = ValidateDataView(
         context, receiver, 'get DataView.prototype.byte_offset');
     if (WasNeutered(dataView)) {
@@ -415,19 +416,19 @@ namespace data_view {
   }
 
   transitioning javascript builtin DataViewPrototypeGetUint8(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     const offset: Object = arguments.length > 0 ? arguments[0] : Undefined;
     return DataViewGet(context, receiver, offset, Undefined, UINT8_ELEMENTS);
   }
 
   transitioning javascript builtin DataViewPrototypeGetInt8(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     const offset: Object = arguments.length > 0 ? arguments[0] : Undefined;
     return DataViewGet(context, receiver, offset, Undefined, INT8_ELEMENTS);
   }
 
   transitioning javascript builtin DataViewPrototypeGetUint16(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     const offset: Object = arguments.length > 0 ? arguments[0] : Undefined;
     const isLittleEndian: Object =
         arguments.length > 1 ? arguments[1] : Undefined;
@@ -436,7 +437,7 @@ namespace data_view {
   }
 
   transitioning javascript builtin DataViewPrototypeGetInt16(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     const offset: Object = arguments.length > 0 ? arguments[0] : Undefined;
     const isLittleEndian: Object =
         arguments.length > 1 ? arguments[1] : Undefined;
@@ -445,7 +446,7 @@ namespace data_view {
   }
 
   transitioning javascript builtin DataViewPrototypeGetUint32(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     const offset: Object = arguments.length > 0 ? arguments[0] : Undefined;
     const isLittleEndian: Object =
         arguments.length > 1 ? arguments[1] : Undefined;
@@ -454,7 +455,7 @@ namespace data_view {
   }
 
   transitioning javascript builtin DataViewPrototypeGetInt32(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     const offset: Object = arguments.length > 0 ? arguments[0] : Undefined;
     const isLittleEndian: Object =
         arguments.length > 1 ? arguments[1] : Undefined;
@@ -463,7 +464,7 @@ namespace data_view {
   }
 
   transitioning javascript builtin DataViewPrototypeGetFloat32(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     const offset: Object = arguments.length > 0 ? arguments[0] : Undefined;
     const isLittleEndian: Object =
         arguments.length > 1 ? arguments[1] : Undefined;
@@ -472,7 +473,7 @@ namespace data_view {
   }
 
   transitioning javascript builtin DataViewPrototypeGetFloat64(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     const offset: Object = arguments.length > 0 ? arguments[0] : Undefined;
     const isLittleEndian: Object =
         arguments.length > 1 ? arguments[1] : Undefined;
@@ -481,7 +482,7 @@ namespace data_view {
   }
 
   transitioning javascript builtin DataViewPrototypeGetBigUint64(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     const offset: Object = arguments.length > 0 ? arguments[0] : Undefined;
     const isLittleEndian: Object =
         arguments.length > 1 ? arguments[1] : Undefined;
@@ -490,7 +491,7 @@ namespace data_view {
   }
 
   transitioning javascript builtin DataViewPrototypeGetBigInt64(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     const offset: Object = arguments.length > 0 ? arguments[0] : Undefined;
     const isLittleEndian: Object =
         arguments.length > 1 ? arguments[1] : Undefined;
@@ -717,7 +718,7 @@ namespace data_view {
   }
 
   transitioning javascript builtin DataViewPrototypeSetUint8(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     const offset: Object = arguments.length > 0 ? arguments[0] : Undefined;
     const value: Object = arguments.length > 1 ? arguments[1] : Undefined;
     return DataViewSet(
@@ -725,7 +726,7 @@ namespace data_view {
   }
 
   transitioning javascript builtin DataViewPrototypeSetInt8(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     const offset: Object = arguments.length > 0 ? arguments[0] : Undefined;
     const value: Object = arguments.length > 1 ? arguments[1] : Undefined;
     return DataViewSet(
@@ -733,7 +734,7 @@ namespace data_view {
   }
 
   transitioning javascript builtin DataViewPrototypeSetUint16(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     const offset: Object = arguments.length > 0 ? arguments[0] : Undefined;
     const value: Object = arguments.length > 1 ? arguments[1] : Undefined;
     const isLittleEndian: Object =
@@ -743,7 +744,7 @@ namespace data_view {
   }
 
   transitioning javascript builtin DataViewPrototypeSetInt16(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     const offset: Object = arguments.length > 0 ? arguments[0] : Undefined;
     const value: Object = arguments.length > 1 ? arguments[1] : Undefined;
     const isLittleEndian: Object =
@@ -753,7 +754,7 @@ namespace data_view {
   }
 
   transitioning javascript builtin DataViewPrototypeSetUint32(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     const offset: Object = arguments.length > 0 ? arguments[0] : Undefined;
     const value: Object = arguments.length > 1 ? arguments[1] : Undefined;
     const isLittleEndian: Object =
@@ -763,7 +764,7 @@ namespace data_view {
   }
 
   transitioning javascript builtin DataViewPrototypeSetInt32(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     const offset: Object = arguments.length > 0 ? arguments[0] : Undefined;
     const value: Object = arguments.length > 1 ? arguments[1] : Undefined;
     const isLittleEndian: Object =
@@ -773,7 +774,7 @@ namespace data_view {
   }
 
   transitioning javascript builtin DataViewPrototypeSetFloat32(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     const offset: Object = arguments.length > 0 ? arguments[0] : Undefined;
     const value: Object = arguments.length > 1 ? arguments[1] : Undefined;
     const isLittleEndian: Object =
@@ -783,7 +784,7 @@ namespace data_view {
   }
 
   transitioning javascript builtin DataViewPrototypeSetFloat64(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     const offset: Object = arguments.length > 0 ? arguments[0] : Undefined;
     const value: Object = arguments.length > 1 ? arguments[1] : Undefined;
     const isLittleEndian: Object =
@@ -793,7 +794,7 @@ namespace data_view {
   }
 
   transitioning javascript builtin DataViewPrototypeSetBigUint64(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     const offset: Object = arguments.length > 0 ? arguments[0] : Undefined;
     const value: Object = arguments.length > 1 ? arguments[1] : Undefined;
     const isLittleEndian: Object =
@@ -803,7 +804,7 @@ namespace data_view {
   }
 
   transitioning javascript builtin DataViewPrototypeSetBigInt64(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     const offset: Object = arguments.length > 0 ? arguments[0] : Undefined;
     const value: Object = arguments.length > 1 ? arguments[1] : Undefined;
     const isLittleEndian: Object =

src/builtins/extras-utils.tq

@@ -8,17 +8,18 @@ namespace extras_utils {
   extern runtime PromiseStatus(Context, Object): Smi;
 
   javascript builtin ExtrasUtilsCreatePrivateSymbol(
-      context: Context, receiver: Object, ...arguments): HeapObject {
+      js-implicit context: Context,
+      receiver: Object)(...arguments): HeapObject {
     return CreatePrivateSymbol(context, arguments[0]);
   }
 
   javascript builtin ExtrasUtilsMarkPromiseAsHandled(
-      context: Context, receiver: Object, ...arguments): Undefined {
+      js-implicit context: Context, receiver: Object)(...arguments): Undefined {
     return PromiseMarkAsHandled(context, arguments[0]);
   }
 
   javascript builtin ExtrasUtilsPromiseState(
-      context: Context, receiver: Object, ...arguments): Smi {
+      js-implicit context: Context, receiver: Object)(...arguments): Smi {
     return PromiseStatus(context, arguments[0]);
   }
 }

src/builtins/object-fromentries.tq

@@ -33,8 +33,8 @@ namespace object {
   }
 
   transitioning javascript builtin
-  ObjectFromEntries(implicit context: Context)(receiver: Object, ...arguments):
-      Object {
+  ObjectFromEntries(js-implicit context: Context, receiver: Object)(
+      ...arguments): Object {
     const iterable: Object = arguments[0];
     try {
       if (IsNullOrUndefined(iterable)) goto Throw;

src/builtins/object.tq

@@ -48,7 +48,7 @@ namespace object {
 namespace object_isextensible {
   // ES6 section 19.1.2.11 Object.isExtensible ( O )
   transitioning javascript builtin ObjectIsExtensible(
-      implicit context: Context)(_receiver: Object, object: Object): Object {
+      js-implicit context: Context)(_receiver: Object, object: Object): Object {
     return object::ObjectIsExtensible(object);
   }
 }  // namespace object_isextensible
@@ -56,7 +56,7 @@ namespace object_isextensible {
 namespace object_preventextensions {
   // ES6 section 19.1.2.11 Object.isExtensible ( O )
   transitioning javascript builtin ObjectPreventExtensions(
-      implicit context: Context)(_receiver: Object, object: Object): Object {
+      js-implicit context: Context)(_receiver: Object, object: Object): Object {
     return object::ObjectPreventExtensionsThrow(object);
   }
 }  // namespace object_preventextensions

src/builtins/proxy-constructor.tq

@@ -6,17 +6,14 @@
 
 namespace proxy {
 
-  extern macro ProxiesCodeStubAssembler::GetProxyConstructorJSNewTarget():
-      Object;
-
   // ES #sec-proxy-constructor
   // https://tc39.github.io/ecma262/#sec-proxy-constructor
   transitioning javascript builtin
-  ProxyConstructor(implicit context: Context)(
-      _receiver: Object, target: Object, handler: Object): JSProxy {
+  ProxyConstructor(
+      js-implicit context: Context, receiver: Object,
+      newTarget: Object)(target: Object, handler: Object): JSProxy {
     try {
       // 1. If NewTarget is undefined, throw a TypeError exception.
-      const newTarget: Object = GetProxyConstructorJSNewTarget();
       if (newTarget == Undefined) {
         ThrowTypeError(kConstructorNotFunction, 'Proxy');
       }

src/builtins/proxy-revoke.tq

@@ -9,7 +9,7 @@ namespace proxy {
   // Proxy Revocation Functions
   // https://tc39.github.io/ecma262/#sec-proxy-revocation-functions
   transitioning javascript builtin
-  ProxyRevoke(implicit context: Context)(): Undefined {
+  ProxyRevoke(js-implicit context: Context)(): Undefined {
     // 1. Let p be F.[[RevocableProxy]].
     const proxyObject: Object = context[PROXY_SLOT];
 

src/builtins/reflect.tq

@@ -9,7 +9,7 @@ namespace reflect {
 
   // ES6 section 26.1.10 Reflect.isExtensible
   transitioning javascript builtin ReflectIsExtensible(
-      implicit context: Context)(_receiver: Object, object: Object): Object {
+      js-implicit context: Context)(_receiver: Object, object: Object): Object {
     const objectJSReceiver = Cast<JSReceiver>(object)
         otherwise ThrowTypeError(kCalledOnNonObject, 'Reflect.isExtensible');
     return object::ObjectIsExtensible(objectJSReceiver);
@@ -17,7 +17,7 @@ namespace reflect {
 
   // ES6 section 26.1.12 Reflect.preventExtensions
   transitioning javascript builtin ReflectPreventExtensions(
-      implicit context: Context)(_receiver: Object, object: Object): Object {
+      js-implicit context: Context)(_receiver: Object, object: Object): Object {
     const objectJSReceiver = Cast<JSReceiver>(object)
         otherwise ThrowTypeError(kCalledOnNonObject, 'Reflect.preventExtensions');
     return object::ObjectPreventExtensionsDontThrow(objectJSReceiver);

src/builtins/regexp-replace.tq

@@ -208,7 +208,7 @@ namespace regexp_replace {
   }
 
   transitioning javascript builtin RegExpPrototypeReplace(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     const methodName: constexpr string = 'RegExp.prototype.@@replace';
 
     // RegExpPrototypeReplace is a bit of a beast - a summary of dispatch logic:

src/builtins/string-endswith.tq

@@ -28,7 +28,7 @@ namespace string {
 
   // https://tc39.github.io/ecma262/#sec-string.prototype.endswith
   transitioning javascript builtin StringPrototypeEndsWith(
-      context: Context, receiver: Object, ...arguments): Boolean {
+      js-implicit context: Context, receiver: Object)(...arguments): Boolean {
     const searchString: Object = arguments[0];
     const endPosition: Object = arguments[1];
 

src/builtins/string-html.tq

@@ -22,22 +22,23 @@ namespace string_html {
 
   // https://tc39.github.io/ecma262/#sec-string.prototype.anchor
   transitioning javascript builtin StringPrototypeAnchor(
-      context: Context, receiver: Object, ...arguments): String {
+      js-implicit context: Context, receiver: Object)(...arguments): String {
     return CreateHTML(
         receiver, 'String.prototype.anchor', 'a', 'name', arguments[0]);
   }
 
   // https://tc39.github.io/ecma262/#sec-string.prototype.big
   transitioning javascript builtin
-  StringPrototypeBig(context: Context, receiver: Object, ...arguments): String {
+  StringPrototypeBig(js-implicit context: Context, receiver: Object)(
+      ...arguments): String {
     return CreateHTML(
         receiver, 'String.prototype.big', 'big', kEmptyString, kEmptyString);
   }
 
   // https://tc39.github.io/ecma262/#sec-string.prototype.blink
   transitioning javascript builtin
-  StringPrototypeBlink(context: Context, receiver: Object, ...arguments):
-      String {
+  StringPrototypeBlink(js-implicit context: Context, receiver: Object)(
+      ...arguments): String {
     return CreateHTML(
         receiver, 'String.prototype.blink', 'blink', kEmptyString,
         kEmptyString);
@@ -45,56 +46,56 @@ namespace string_html {
 
   // https://tc39.github.io/ecma262/#sec-string.prototype.bold
   transitioning javascript builtin
-  StringPrototypeBold(context: Context, receiver: Object, ...arguments):
-      String {
+  StringPrototypeBold(js-implicit context: Context, receiver: Object)(
+      ...arguments): String {
     return CreateHTML(
         receiver, 'String.prototype.bold', 'b', kEmptyString, kEmptyString);
   }
 
   // https://tc39.github.io/ecma262/#sec-string.prototype.fontcolor
   transitioning javascript builtin
-  StringPrototypeFontcolor(context: Context, receiver: Object, ...arguments):
-      String {
+  StringPrototypeFontcolor(js-implicit context: Context, receiver: Object)(
+      ...arguments): String {
     return CreateHTML(
         receiver, 'String.prototype.fontcolor', 'font', 'color', arguments[0]);
   }
 
   // https://tc39.github.io/ecma262/#sec-string.prototype.fontsize
   transitioning javascript builtin
-  StringPrototypeFontsize(context: Context, receiver: Object, ...arguments):
-      String {
+  StringPrototypeFontsize(js-implicit context: Context, receiver: Object)(
+      ...arguments): String {
     return CreateHTML(
         receiver, 'String.prototype.fontsize', 'font', 'size', arguments[0]);
   }
 
   // https://tc39.github.io/ecma262/#sec-string.prototype.fixed
   transitioning javascript builtin
-  StringPrototypeFixed(context: Context, receiver: Object, ...arguments):
-      String {
+  StringPrototypeFixed(js-implicit context: Context, receiver: Object)(
+      ...arguments): String {
     return CreateHTML(
         receiver, 'String.prototype.fixed', 'tt', kEmptyString, kEmptyString);
   }
 
   // https://tc39.github.io/ecma262/#sec-string.prototype.italics
   transitioning javascript builtin
-  StringPrototypeItalics(context: Context, receiver: Object, ...arguments):
-      String {
+  StringPrototypeItalics(js-implicit context: Context, receiver: Object)(
+      ...arguments): String {
     return CreateHTML(
         receiver, 'String.prototype.italics', 'i', kEmptyString, kEmptyString);
   }
 
   // https://tc39.github.io/ecma262/#sec-string.prototype.link
   transitioning javascript builtin
-  StringPrototypeLink(context: Context, receiver: Object, ...arguments):
-      String {
+  StringPrototypeLink(js-implicit context: Context, receiver: Object)(
+      ...arguments): String {
     return CreateHTML(
         receiver, 'String.prototype.link', 'a', 'href', arguments[0]);
   }
 
   // https://tc39.github.io/ecma262/#sec-string.prototype.small
   transitioning javascript builtin
-  StringPrototypeSmall(context: Context, receiver: Object, ...arguments):
-      String {
+  StringPrototypeSmall(js-implicit context: Context, receiver: Object)(
+      ...arguments): String {
     return CreateHTML(
         receiver, 'String.prototype.small', 'small', kEmptyString,
         kEmptyString);
@@ -102,8 +103,8 @@ namespace string_html {
 
   // https://tc39.github.io/ecma262/#sec-string.prototype.strike
   transitioning javascript builtin
-  StringPrototypeStrike(context: Context, receiver: Object, ...arguments):
-      String {
+  StringPrototypeStrike(js-implicit context: Context, receiver: Object)(
+      ...arguments): String {
     return CreateHTML(
         receiver, 'String.prototype.strike', 'strike', kEmptyString,
         kEmptyString);
@@ -111,14 +112,16 @@ namespace string_html {
 
   // https://tc39.github.io/ecma262/#sec-string.prototype.sub
   transitioning javascript builtin
-  StringPrototypeSub(context: Context, receiver: Object, ...arguments): String {
+  StringPrototypeSub(js-implicit context: Context, receiver: Object)(
+      ...arguments): String {
     return CreateHTML(
         receiver, 'String.prototype.sub', 'sub', kEmptyString, kEmptyString);
   }
 
   // https://tc39.github.io/ecma262/#sec-string.prototype.sup
   transitioning javascript builtin
-  StringPrototypeSup(context: Context, receiver: Object, ...arguments): String {
+  StringPrototypeSup(js-implicit context: Context, receiver: Object)(
+      ...arguments): String {
     return CreateHTML(
         receiver, 'String.prototype.sup', 'sup', kEmptyString, kEmptyString);
   }

src/builtins/string-iterator.tq

@@ -17,7 +17,7 @@ namespace string_iterator {
 
   // ES6 #sec-string.prototype-@@iterator
   transitioning javascript builtin StringPrototypeIterator(
-      implicit context: Context)(receiver: Object): JSStringIterator {
+      js-implicit context: Context)(receiver: Object): JSStringIterator {
     const name: String =
         ToThisString(receiver, 'String.prototype[Symbol.iterator]');
     const index: Smi = 0;
@@ -26,7 +26,7 @@ namespace string_iterator {
 
   // ES6 #sec-%stringiteratorprototype%.next
   transitioning javascript builtin StringIteratorPrototypeNext(
-      implicit context: Context)(receiver: Object): JSObject {
+      js-implicit context: Context)(receiver: Object): JSObject {
     const iterator = Cast<JSStringIterator>(receiver) otherwise ThrowTypeError(
         kIncompatibleMethodReceiver, 'String Iterator.prototype.next',
         receiver);

src/builtins/string-repeat.tq

@@ -28,7 +28,7 @@ namespace string_repeat {
 
   // https://tc39.github.io/ecma262/#sec-string.prototype.repeat
   transitioning javascript builtin StringPrototypeRepeat(
-      context: Context, receiver: Object, count: Object): String {
+      js-implicit context: Context, receiver: Object)(count: Object): String {
     // 1. Let O be ? RequireObjectCoercible(this value).
     // 2. Let S be ? ToString(O).
     const s: String = ToThisString(receiver, kBuiltinName);

src/builtins/string-slice.tq

@@ -9,7 +9,7 @@ namespace string_slice {
   // ES6 #sec-string.prototype.slice ( start, end )
   // https://tc39.github.io/ecma262/#sec-string.prototype.slice
   transitioning javascript builtin StringPrototypeSlice(
-      implicit context: Context)(receiver: Object, ...arguments): String {
+      js-implicit context: Context, receiver: Object)(...arguments): String {
     // 1. Let O be ? RequireObjectCoercible(this value).
     // 2. Let S be ? ToString(O).
     const string: String = ToThisString(receiver, 'String.prototype.slice');

src/builtins/string-startswith.tq

@@ -19,7 +19,7 @@ namespace string {
 
   // https://tc39.github.io/ecma262/#sec-string.prototype.startswith
   transitioning javascript builtin StringPrototypeStartsWith(
-      context: Context, receiver: Object, ...arguments): Boolean {
+      js-implicit context: Context, receiver: Object)(...arguments): Boolean {
     const searchString: Object = arguments[0];
     const position: Object = arguments[1];
 

src/builtins/string-substring.tq

@@ -28,7 +28,7 @@ namespace string_substring {
 
   // ES6 #sec-string.prototype.substring
   transitioning javascript builtin StringPrototypeSubstring(
-      implicit context: Context)(receiver: Object, ...arguments): String {
+      js-implicit context: Context, receiver: Object)(...arguments): String {
     // Check that {receiver} is coercible to Object and convert it to a String.
     const string: String = ToThisString(receiver, 'String.prototype.substring');
     const length = string.length_smi;

src/builtins/string.tq

@@ -7,13 +7,15 @@
 namespace string {
   // ES6 #sec-string.prototype.tostring
   transitioning javascript builtin
-  StringPrototypeToString(implicit context: Context)(receiver: Object): Object {
+  StringPrototypeToString(js-implicit context: Context)(receiver: Object):
+      Object {
     return ToThisValue(receiver, kString, 'String.prototype.toString');
   }
 
   // ES6 #sec-string.prototype.valueof
   transitioning javascript builtin
-  StringPrototypeValueOf(implicit context: Context)(receiver: Object): Object {
+  StringPrototypeValueOf(js-implicit context: Context)(receiver: Object):
+      Object {
     return ToThisValue(receiver, kString, 'String.prototype.valueOf');
   }
 
@@ -70,7 +72,8 @@ namespace string {
 
   // ES6 #sec-string.prototype.charat
   transitioning javascript builtin StringPrototypeCharAt(
-      implicit context: Context)(receiver: Object, position: Object): Object {
+      js-implicit context: Context,
+      receiver: Object)(position: Object): Object {
     try {
       GenerateStringAt(receiver, position, 'String.prototype.charAt')
           otherwise IfInBounds, IfOutOfBounds;
@@ -86,7 +89,8 @@ namespace string {
 
   // ES6 #sec-string.prototype.charcodeat
   transitioning javascript builtin StringPrototypeCharCodeAt(
-      implicit context: Context)(receiver: Object, position: Object): Object {
+      js-implicit context: Context,
+      receiver: Object)(position: Object): Object {
     try {
       GenerateStringAt(receiver, position, 'String.prototype.charCodeAt')
           otherwise IfInBounds, IfOutOfBounds;
@@ -102,7 +106,8 @@ namespace string {
 
   // ES6 #sec-string.prototype.codepointat
   transitioning javascript builtin StringPrototypeCodePointAt(
-      implicit context: Context)(receiver: Object, position: Object): Object {
+      js-implicit context: Context,
+      receiver: Object)(position: Object): Object {
     try {
       GenerateStringAt(receiver, position, 'String.prototype.codePointAt')
           otherwise IfInBounds, IfOutOfBounds;
@@ -121,7 +126,7 @@ namespace string {
   // ES6 String.prototype.concat(...args)
   // ES6 #sec-string.prototype.concat
   transitioning javascript builtin StringPrototypeConcat(
-      implicit context: Context)(receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     // Check that {receiver} is coercible to Object and convert it to a String.
     let string: String = ToThisString(receiver, 'String.prototype.concat');
 

src/builtins/typed-array-every.tq

@@ -29,8 +29,8 @@ namespace typed_array_every {
 
   // https://tc39.github.io/ecma262/#sec-%typedarray%.prototype.every
   transitioning javascript builtin
-  TypedArrayPrototypeEvery(implicit context: Context)(
-      receiver: Object, ...arguments): Object {
+  TypedArrayPrototypeEvery(js-implicit context: Context, receiver: Object)(
+      ...arguments): Object {
     // arguments[0] = callback
     // arguments[1] = thisArg
     try {

src/builtins/typed-array-filter.tq

@@ -10,7 +10,7 @@ namespace typed_array_filter {
 
   // https://tc39.github.io/ecma262/#sec-%typedarray%.prototype.filter
   transitioning javascript builtin TypedArrayPrototypeFilter(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     // arguments[0] = callback
     // arguments[1] = thisArg
     try {

src/builtins/typed-array-find.tq

@@ -29,8 +29,8 @@ namespace typed_array_find {
 
   // https://tc39.github.io/ecma262/#sec-%typedarray%.prototype.find
   transitioning javascript builtin
-  TypedArrayPrototypeFind(implicit context:
-                              Context)(receiver: Object, ...arguments): Object {
+  TypedArrayPrototypeFind(js-implicit context: Context, receiver: Object)(
+      ...arguments): Object {
     // arguments[0] = callback
     // arguments[1] = thisArg
     try {

src/builtins/typed-array-findindex.tq

@@ -29,8 +29,8 @@ namespace typed_array_findindex {
 
   // https://tc39.github.io/ecma262/#sec-%typedarray%.prototype.findIndex
   transitioning javascript builtin
-  TypedArrayPrototypeFindIndex(implicit context: Context)(
-      receiver: Object, ...arguments): Object {
+  TypedArrayPrototypeFindIndex(js-implicit context: Context, receiver: Object)(
+      ...arguments): Object {
     // arguments[0] = callback
     // arguments[1] = thisArg.
     try {

src/builtins/typed-array-foreach.tq

@@ -25,8 +25,8 @@ namespace typed_array_foreach {
 
   // https://tc39.github.io/ecma262/#sec-%typedarray%.prototype.every
   transitioning javascript builtin
-  TypedArrayPrototypeForEach(implicit context: Context)(
-      receiver: Object, ...arguments): Object {
+  TypedArrayPrototypeForEach(js-implicit context: Context, receiver: Object)(
+      ...arguments): Object {
     // arguments[0] = callback
     // arguments[1] = this_arg.
 

src/builtins/typed-array-reduce.tq

@@ -35,8 +35,8 @@ namespace typed_array_reduce {
 
   // https://tc39.github.io/ecma262/#sec-%typedarray%.prototype.reduce
   transitioning javascript builtin
-  TypedArrayPrototypeReduce(implicit context: Context)(
-      receiver: Object, ...arguments): Object {
+  TypedArrayPrototypeReduce(js-implicit context: Context, receiver: Object)(
+      ...arguments): Object {
     // arguments[0] = callback
     // arguments[1] = initialValue.
     try {

src/builtins/typed-array-reduceright.tq

@@ -35,8 +35,8 @@ namespace typed_array_reduceright {
 
   // https://tc39.github.io/ecma262/#sec-%typedarray%.prototype.reduceright
   transitioning javascript builtin
-  TypedArrayPrototypeReduceRight(implicit context: Context)(
-      receiver: Object, ...arguments): Object {
+  TypedArrayPrototypeReduceRight(
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     // arguments[0] = callback
     // arguments[1] = initialValue.
     try {

src/builtins/typed-array-slice.tq

@@ -53,7 +53,7 @@ namespace typed_array_slice {
 
   // https://tc39.github.io/ecma262/#sec-%typedarray%.prototype.slice
   transitioning javascript builtin TypedArrayPrototypeSlice(
-      context: Context, receiver: Object, ...arguments): Object {
+      js-implicit context: Context, receiver: Object)(...arguments): Object {
     // arguments[0] = start
     // arguments[1] = end
 

src/builtins/typed-array-some.tq

@@ -29,8 +29,8 @@ namespace typed_array_some {
 
   // https://tc39.github.io/ecma262/#sec-%typedarray%.prototype.some
   transitioning javascript builtin
-  TypedArrayPrototypeSome(implicit context:
-                              Context)(receiver: Object, ...arguments): Object {
+  TypedArrayPrototypeSome(js-implicit context: Context, receiver: Object)(
+      ...arguments): Object {
     // arguments[0] = callback
     // arguments[1] = thisArg.
     try {

src/builtins/typed-array-subarray.tq

@@ -5,7 +5,8 @@
 namespace typed_array_subarray {
   // ES %TypedArray%.prototype.subarray
   transitioning javascript builtin TypedArrayPrototypeSubArray(
-      context: Context, receiver: Object, ...arguments): JSTypedArray {
+      js-implicit context: Context,
+      receiver: Object)(...arguments): JSTypedArray {
     const methodName: constexpr string = '%TypedArray%.prototype.subarray';
 
     // 1. Let O be the this value.

src/builtins/typed-array.tq

@@ -278,7 +278,8 @@ namespace typed_array {
 
   // https://tc39.github.io/ecma262/#sec-%typedarray%.prototype.sort
   transitioning javascript builtin TypedArrayPrototypeSort(
-      context: Context, receiver: Object, ...arguments): JSTypedArray {
+      js-implicit context: Context,
+      receiver: Object)(...arguments): JSTypedArray {
     // 1. If comparefn is not undefined and IsCallable(comparefn) is false,
     //    throw a TypeError exception.
     const comparefnObj: Object =

src/torque/ast.h

@@ -15,6 +15,7 @@
 #include "src/base/optional.h"
 #include "src/torque/constants.h"
 #include "src/torque/source-positions.h"
+#include "src/torque/utils.h"
 
 namespace v8 {
 namespace internal {
@@ -559,14 +560,18 @@ struct NewExpression : Expression {
   std::vector<NameAndExpression> initializers;
 };
 
+enum class ImplicitKind { kNoImplicit, kJSImplicit, kImplicit };
+
 struct ParameterList {
   std::vector<Identifier*> names;
   std::vector<TypeExpression*> types;
-  size_t implicit_count;
-  bool has_varargs;
-  std::string arguments_variable;
+  ImplicitKind implicit_kind = ImplicitKind::kNoImplicit;
+  SourcePosition implicit_kind_pos = SourcePosition::Invalid();
+  size_t implicit_count = 0;
+  bool has_varargs = false;
+  std::string arguments_variable = "";
 
-  static ParameterList Empty() { return ParameterList{{}, {}, 0, false, ""}; }
+  static ParameterList Empty() { return {}; }
   std::vector<TypeExpression*> GetImplicitTypes() {
     return std::vector<TypeExpression*>(types.begin(),
                                         types.begin() + implicit_count);
@@ -821,6 +826,11 @@ struct NameAndTypeExpression {
   TypeExpression* type;
 };
 
+struct ImplicitParameters {
+  Identifier* kind;
+  std::vector<NameAndTypeExpression> parameters;
+};
+
 struct StructFieldExpression {
   NameAndTypeExpression name_and_type;
   bool const_qualified;
@@ -880,7 +890,12 @@ struct MacroDeclaration : CallableNode {
                    const LabelAndTypesVector& labels)
       : CallableNode(kind, pos, transitioning, std::move(name),
                      std::move(parameters), return_type, labels),
-        op(std::move(op)) {}
+        op(std::move(op)) {
+    if (parameters.implicit_kind == ImplicitKind::kJSImplicit) {
+      Error("Cannot use \"js-implicit\" with macros, use \"implicit\" instead.")
+          .Position(parameters.implicit_kind_pos);
+    }
+  }
   base::Optional<std::string> op;
 };
 
@@ -904,7 +919,11 @@ struct IntrinsicDeclaration : CallableNode {
   IntrinsicDeclaration(SourcePosition pos, std::string name,
                        ParameterList parameters, TypeExpression* return_type)
       : CallableNode(kKind, pos, false, std::move(name), std::move(parameters),
-                     return_type, {}) {}
+                     return_type, {}) {
+    if (parameters.implicit_kind != ImplicitKind::kNoImplicit) {
+      Error("Intinsics cannot have implicit parameters.");
+    }
+  }
 };
 
 struct TorqueMacroDeclaration : MacroDeclaration {
@@ -928,7 +947,21 @@ struct BuiltinDeclaration : CallableNode {
                      TypeExpression* return_type)
       : CallableNode(kind, pos, transitioning, std::move(name),
                      std::move(parameters), return_type, {}),
-        javascript_linkage(javascript_linkage) {}
+        javascript_linkage(javascript_linkage) {
+    if (parameters.implicit_kind == ImplicitKind::kJSImplicit &&
+        !javascript_linkage) {
+      Error(
+          "\"js-implicit\" is for implicit parameters passed according to the "
+          "JavaScript calling convention. Use \"implicit\" instead.");
+    }
+    if (parameters.implicit_kind == ImplicitKind::kImplicit &&
+        javascript_linkage) {
+      Error(
+          "The JavaScript calling convention implicitly passes a fixed set of "
+          "values. Use \"js-implicit\" to refer to those.")
+          .Position(parameters.implicit_kind_pos);
+    }
+  }
   bool javascript_linkage;
 };
 

src/torque/constants.h

@@ -22,6 +22,7 @@ static const char* const BOOL_TYPE_STRING = "bool";
 static const char* const VOID_TYPE_STRING = "void";
 static const char* const ARGUMENTS_TYPE_STRING = "Arguments";
 static const char* const CONTEXT_TYPE_STRING = "Context";
+static const char* const JS_FUNCTION_TYPE_STRING = "JSFunction";
 static const char* const MAP_TYPE_STRING = "Map";
 static const char* const OBJECT_TYPE_STRING = "Object";
 static const char* const HEAP_OBJECT_TYPE_STRING = "HeapObject";

src/torque/declaration-visitor.cc

@@ -76,28 +76,12 @@ Builtin* DeclarationVisitor::CreateBuiltin(BuiltinDeclaration* decl,
   Builtin::Kind kind = !javascript ? Builtin::kStub
                                    : varargs ? Builtin::kVarArgsJavaScript
                                              : Builtin::kFixedArgsJavaScript;
-  const Type* context_type =
-      Declarations::LookupGlobalType(CONTEXT_TYPE_STRING);
-  if (signature.types().size() == 0 ||
-      !(signature.types()[0] == context_type)) {
-    Error("First parameter to builtin ", decl->name, " must be of type ",
-          *context_type);
-  }
 
   if (varargs && !javascript) {
     Error("Rest parameters require ", decl->name,
           " to be a JavaScript builtin");
   }
 
-  if (javascript) {
-    if (signature.types().size() >= 2 &&
-        !(signature.types()[1] ==
-          Declarations::LookupGlobalType(OBJECT_TYPE_STRING))) {
-      Error("Second parameter to javascript builtin ", decl->name, " is ",
-            *signature.types()[1], " but should be Object");
-    }
-  }
-
   for (size_t i = 0; i < signature.types().size(); ++i) {
     if (const StructType* type =
             StructType::DynamicCast(signature.types()[i])) {
@@ -136,8 +120,7 @@ void DeclarationVisitor::Visit(ExternalRuntimeDeclaration* decl,
                                const Signature& signature,
                                base::Optional<Statement*> body) {
   if (signature.parameter_types.types.size() == 0 ||
-      !(signature.parameter_types.types[0] ==
-        Declarations::LookupGlobalType(CONTEXT_TYPE_STRING))) {
+      !(signature.parameter_types.types[0] == TypeOracle::GetContextType())) {
     ReportError(
         "first parameter to runtime functions has to be the context and have "
         "type Context, but found type ",

src/torque/earley-parser.cc

@@ -159,26 +159,21 @@ Symbol* Lexer::MatchToken(InputPosition* pos, InputPosition end) {
       symbol = &pair.second;
     }
   }
-  // Check if matched pattern coincides with a keyword. Prefer the keyword in
-  // this case.
-  if (*pos != token_start) {
-    auto found_keyword = keywords_.find(std::string(token_start, *pos));
-    if (found_keyword != keywords_.end()) {
-      return &found_keyword->second;
-    }
-    return symbol;
-  }
-  // Now check for a keyword (that doesn't overlap with a pattern).
-  // Iterate from the end to ensure that if one keyword is a prefix of another,
-  // we first try to match the longer one.
+  size_t pattern_size = *pos - token_start;
+
+  // Now check for keywords. Prefer keywords over patterns unless the pattern is
+  // longer. Iterate from the end to ensure that if one keyword is a prefix of
+  // another, we first try to match the longer one.
   for (auto it = keywords_.rbegin(); it != keywords_.rend(); ++it) {
     const std::string& keyword = it->first;
-    if (static_cast<size_t>(end - *pos) < keyword.size()) continue;
-    if (keyword == std::string(*pos, *pos + keyword.size())) {
-      *pos += keyword.size();
+    if (static_cast<size_t>(end - token_start) < keyword.size()) continue;
+    if (keyword.size() >= pattern_size &&
+        keyword == std::string(token_start, token_start + keyword.size())) {
+      *pos = token_start + keyword.size();
       return &it->second;
     }
   }
+  if (pattern_size > 0) return symbol;
   return nullptr;
 }
 

src/torque/earley-parser.h

@@ -53,6 +53,8 @@ enum class ParseResultHolderBase::TypeId {
   kLabelBlockPtr,
   kOptionalLabelBlockPtr,
   kNameAndTypeExpression,
+  kImplicitParameters,
+  kOptionalImplicitParameters,
   kNameAndExpression,
   kConditionalAnnotation,
   kOptionalConditionalAnnotation,

src/torque/implementation-visitor.cc

@@ -415,61 +415,128 @@ void ImplementationVisitor::Visit(Builtin* builtin) {
 
   BlockBindings<LocalValue> parameter_bindings(&ValueBindingsManager::Get());
 
-  // Context
-  const bool context_is_implicit = signature.implicit_count > 0;
-  std::string parameter0 =
-      AddParameter(0, builtin, &parameters, &parameter_types,
-                   &parameter_bindings, context_is_implicit);
-  source_out() << "  TNode<Context> " << parameter0
-               << " = UncheckedCast<Context>(Parameter("
-               << "Descriptor::kContext));\n";
-  source_out() << "  USE(" << parameter0 << ");\n";
-
-  size_t first = 1;
-  if (builtin->IsVarArgsJavaScript()) {
-    DCHECK(signature.parameter_types.var_args);
-    source_out()
-        << "  Node* argc = Parameter(Descriptor::kJSActualArgumentsCount);\n";
-    std::string parameter1 = AddParameter(
-        1, builtin, &parameters, &parameter_types, &parameter_bindings, true);
-    source_out()
-        << "  TNode<IntPtrT> arguments_length(ChangeInt32ToIntPtr(argc));\n";
-    source_out() << "  TNode<RawPtrT> arguments_frame = "
-                    "UncheckedCast<RawPtrT>(LoadFramePointer());\n";
-    source_out() << "  TorqueStructArguments "
-                    "torque_arguments(GetFrameArguments(arguments_frame, "
-                    "arguments_length));\n";
-    source_out() << "  CodeStubArguments arguments(this, torque_arguments);\n";
-
-    source_out() << "  TNode<Object> " << parameter1
-                 << " = arguments.GetReceiver();\n";
-    source_out() << "USE(" << parameter1 << ");\n";
-    parameters.Push("torque_arguments.frame");
-    parameters.Push("torque_arguments.base");
-    parameters.Push("torque_arguments.length");
-    const Type* arguments_type = TypeOracle::GetArgumentsType();
-    StackRange range = parameter_types.PushMany(LowerType(arguments_type));
-    parameter_bindings.Add(*signature.arguments_variable,
-                           LocalValue{true, VisitResult(arguments_type, range)},
-                           true);
-
-    first = 2;
-  }
-
-  for (size_t i = 0; i < signature.parameter_names.size(); ++i) {
-    if (i < first) continue;
-    const std::string& parameter_name = signature.parameter_names[i]->value;
-    const Type* type = signature.types()[i];
-    const bool mark_as_used = signature.implicit_count > i;
-    std::string var = AddParameter(i, builtin, &parameters, &parameter_types,
-                                   &parameter_bindings, mark_as_used);
-    source_out() << "  " << type->GetGeneratedTypeName() << " " << var << " = "
-                 << "UncheckedCast<" << type->GetGeneratedTNodeTypeName()
-                 << ">(Parameter(Descriptor::k"
-                 << CamelifyString(parameter_name) << "));\n";
-    source_out() << "  USE(" << var << ");\n";
-  }
+  if (builtin->IsVarArgsJavaScript() || builtin->IsFixedArgsJavaScript()) {
+    if (builtin->IsVarArgsJavaScript()) {
+      DCHECK(signature.parameter_types.var_args);
+      if (signature.ExplicitCount() > 0) {
+        Error("Cannot mix explicit parameters with varargs.")
+            .Position(signature.parameter_names[signature.implicit_count]->pos);
+      }
 
+      source_out()
+          << "  Node* argc = Parameter(Descriptor::kJSActualArgumentsCount);\n";
+      source_out()
+          << "  TNode<IntPtrT> arguments_length(ChangeInt32ToIntPtr(argc));\n";
+      source_out() << "  TNode<RawPtrT> arguments_frame = "
+                      "UncheckedCast<RawPtrT>(LoadFramePointer());\n";
+      source_out() << "  TorqueStructArguments "
+                      "torque_arguments(GetFrameArguments(arguments_frame, "
+                      "arguments_length));\n";
+      source_out()
+          << "  CodeStubArguments arguments(this, torque_arguments);\n";
+
+      parameters.Push("torque_arguments.frame");
+      parameters.Push("torque_arguments.base");
+      parameters.Push("torque_arguments.length");
+      const Type* arguments_type = TypeOracle::GetArgumentsType();
+      StackRange range = parameter_types.PushMany(LowerType(arguments_type));
+      parameter_bindings.Add(
+          *signature.arguments_variable,
+          LocalValue{true, VisitResult(arguments_type, range)}, true);
+    }
+
+    for (size_t i = 0; i < signature.implicit_count; ++i) {
+      const std::string& param_name = signature.parameter_names[i]->value;
+      SourcePosition param_pos = signature.parameter_names[i]->pos;
+      std::string generated_name = AddParameter(
+          i, builtin, &parameters, &parameter_types, &parameter_bindings, true);
+      const Type* actual_type = signature.parameter_types.types[i];
+      const Type* expected_type;
+      if (param_name == "context") {
+        source_out() << "  TNode<Context> " << generated_name
+                     << " = UncheckedCast<Context>(Parameter("
+                     << "Descriptor::kContext));\n";
+        source_out() << "  USE(" << generated_name << ");\n";
+        expected_type = TypeOracle::GetContextType();
+      } else if (param_name == "receiver") {
+        source_out()
+            << "  TNode<Object> " << generated_name << " = "
+            << (builtin->IsVarArgsJavaScript()
+                    ? "arguments.GetReceiver()"
+                    : "UncheckedCast<Object>(Parameter(Descriptor::kReceiver))")
+            << ";\n";
+        source_out() << "USE(" << generated_name << ");\n";
+        expected_type = TypeOracle::GetObjectType();
+      } else if (param_name == "newTarget") {
+        source_out() << "  TNode<Object> " << generated_name
+                     << " = UncheckedCast<Object>(Parameter("
+                     << "Descriptor::kJSNewTarget));\n";
+        source_out() << "USE(" << generated_name << ");\n";
+        expected_type = TypeOracle::GetObjectType();
+      } else if (param_name == "target") {
+        source_out() << "  TNode<JSFunction> " << generated_name
+                     << " = UncheckedCast<JSFunction>(Parameter("
+                     << "Descriptor::kJSTarget));\n";
+        source_out() << "USE(" << generated_name << ");\n";
+        expected_type = TypeOracle::GetJSFunctionType();
+      } else {
+        Error(
+            "Unexpected implicit parameter \"", param_name,
+            "\" for JavaScript calling convention, "
+            "expected \"context\", \"receiver\", \"target\", or \"newTarget\"")
+            .Position(param_pos);
+        expected_type = actual_type;
+      }
+      if (actual_type != expected_type) {
+        Error("According to JavaScript calling convention, expected parameter ",
+              param_name, " to have type ", *expected_type, " but found type ",
+              *actual_type)
+            .Position(param_pos);
+      }
+    }
+
+    for (size_t i = signature.implicit_count;
+         i < signature.parameter_names.size(); ++i) {
+      const std::string& parameter_name = signature.parameter_names[i]->value;
+      const Type* type = signature.types()[i];
+      const bool mark_as_used = signature.implicit_count > i;
+      std::string var = AddParameter(i, builtin, &parameters, &parameter_types,
+                                     &parameter_bindings, mark_as_used);
+      source_out() << "  " << type->GetGeneratedTypeName() << " " << var
+                   << " = "
+                   << "UncheckedCast<" << type->GetGeneratedTNodeTypeName()
+                   << ">(Parameter(Descriptor::k"
+                   << CamelifyString(parameter_name) << "));\n";
+      source_out() << "  USE(" << var << ");\n";
+    }
+
+  } else {
+    DCHECK(builtin->IsStub());
+
+    // Context
+    const bool context_is_implicit = signature.implicit_count > 0;
+    std::string parameter0 =
+        AddParameter(0, builtin, &parameters, &parameter_types,
+                     &parameter_bindings, context_is_implicit);
+    source_out() << "  TNode<Context> " << parameter0
+                 << " = UncheckedCast<Context>(Parameter("
+                 << "Descriptor::kContext));\n";
+    source_out() << "  USE(" << parameter0 << ");\n";
+
+    for (size_t i = 1; i < signature.parameter_names.size(); ++i) {
+      const std::string& parameter_name = signature.parameter_names[i]->value;
+      const Type* type = signature.types()[i];
+      const bool mark_as_used = signature.implicit_count > i;
+      std::string var = AddParameter(i, builtin, &parameters, &parameter_types,
+                                     &parameter_bindings, mark_as_used);
+      source_out() << "  " << type->GetGeneratedTypeName() << " " << var
+                   << " = "
+                   << "UncheckedCast<" << type->GetGeneratedTNodeTypeName()
+                   << ">(Parameter(Descriptor::k"
+                   << CamelifyString(parameter_name) << "));\n";
+      source_out() << "  USE(" << var << ");\n";
+    }
+  }
   assembler_ = CfgAssembler(parameter_types);
   const Type* body_result = Visit(*builtin->body());
   if (body_result != TypeOracle::GetNeverType()) {

src/torque/torque-parser.cc

@@ -128,6 +128,14 @@ V8_EXPORT_PRIVATE const ParseResultTypeId
     ParseResultHolder<std::vector<NameAndTypeExpression>>::id =
         ParseResultTypeId::kStdVectorOfNameAndTypeExpression;
 template <>
+V8_EXPORT_PRIVATE const ParseResultTypeId
+    ParseResultHolder<ImplicitParameters>::id =
+        ParseResultTypeId::kImplicitParameters;
+template <>
+V8_EXPORT_PRIVATE const ParseResultTypeId
+    ParseResultHolder<base::Optional<ImplicitParameters>>::id =
+        ParseResultTypeId::kOptionalImplicitParameters;
+template <>
 V8_EXPORT_PRIVATE const ParseResultTypeId
     ParseResultHolder<std::vector<NameAndExpression>>::id =
         ParseResultTypeId::kStdVectorOfNameAndExpression;
@@ -376,59 +384,60 @@ base::Optional<ParseResult> MakeSpreadExpression(
   return ParseResult{result};
 }
 
-template <bool has_varargs>
-base::Optional<ParseResult> MakeParameterListFromTypes(
+base::Optional<ParseResult> MakeImplicitParameterList(
     ParseResultIterator* child_results) {
-  auto implicit_params =
-      child_results->NextAs<std::vector<NameAndTypeExpression>>();
-  auto explicit_types = child_results->NextAs<TypeList>();
-  ParameterList result;
-  result.has_varargs = has_varargs;
-  result.implicit_count = implicit_params.size();
-  for (NameAndTypeExpression& implicit_param : implicit_params) {
-    if (!IsLowerCamelCase(implicit_param.name->value)) {
-      NamingConventionError("Parameter", implicit_param.name, "lowerCamelCase");
-    }
-    result.names.push_back(implicit_param.name);
-    result.types.push_back(implicit_param.type);
-  }
-  for (auto* explicit_type : explicit_types) {
-    result.types.push_back(explicit_type);
+  auto kind = child_results->NextAs<Identifier*>();
+  auto parameters = child_results->NextAs<std::vector<NameAndTypeExpression>>();
+  return ParseResult{ImplicitParameters{kind, parameters}};
+}
+
+void AddParameter(ParameterList* parameter_list, NameAndTypeExpression& param) {
+  if (!IsLowerCamelCase(param.name->value)) {
+    NamingConventionError("Parameter", param.name, "lowerCamelCase");
   }
-  return ParseResult{std::move(result)};
+  parameter_list->names.push_back(param.name);
+  parameter_list->types.push_back(param.type);
 }
 
-template <bool has_varargs>
-base::Optional<ParseResult> MakeParameterListFromNameAndTypeList(
+template <bool has_varargs, bool has_explicit_parameter_names>
+base::Optional<ParseResult> MakeParameterList(
     ParseResultIterator* child_results) {
   auto implicit_params =
-      child_results->NextAs<std::vector<NameAndTypeExpression>>();
-  auto explicit_params =
-      child_results->NextAs<std::vector<NameAndTypeExpression>>();
-  std::string arguments_variable = "";
-  if (child_results->HasNext()) {
-    arguments_variable = child_results->NextAs<std::string>();
-  }
+      child_results->NextAs<base::Optional<ImplicitParameters>>();
   ParameterList result;
-  for (NameAndTypeExpression& pair : implicit_params) {
-    if (!IsLowerCamelCase(pair.name->value)) {
-      NamingConventionError("Parameter", pair.name, "lowerCamelCase");
+  result.has_varargs = has_varargs;
+  result.implicit_count = 0;
+  result.implicit_kind = ImplicitKind::kNoImplicit;
+  if (implicit_params) {
+    result.implicit_count = implicit_params->parameters.size();
+    if (implicit_params->kind->value == "implicit") {
+      result.implicit_kind = ImplicitKind::kImplicit;
+    } else {
+      DCHECK_EQ(implicit_params->kind->value, "js-implicit");
+      result.implicit_kind = ImplicitKind::kJSImplicit;
+    }
+    result.implicit_kind_pos = implicit_params->kind->pos;
+    for (NameAndTypeExpression& implicit_param : implicit_params->parameters) {
+      AddParameter(&result, implicit_param);
     }
-
-    result.names.push_back(std::move(pair.name));
-    result.types.push_back(pair.type);
   }
-  for (NameAndTypeExpression& pair : explicit_params) {
-    if (!IsLowerCamelCase(pair.name->value)) {
-      NamingConventionError("Parameter", pair.name, "lowerCamelCase");
+  if (has_explicit_parameter_names) {
+    auto explicit_params =
+        child_results->NextAs<std::vector<NameAndTypeExpression>>();
+    std::string arguments_variable = "";
+    if (has_varargs) {
+      arguments_variable = child_results->NextAs<std::string>();
+    }
+    for (NameAndTypeExpression& param : explicit_params) {
+      AddParameter(&result, param);
+    }
+    result.arguments_variable = arguments_variable;
+  } else {
+    auto explicit_types = child_results->NextAs<TypeList>();
+    for (auto* explicit_type : explicit_types) {
+      result.types.push_back(explicit_type);
     }
-
-    result.names.push_back(pair.name);
-    result.types.push_back(pair.type);
   }
-  result.implicit_count = implicit_params.size();
-  result.has_varargs = has_varargs;
-  result.arguments_variable = arguments_variable;
   return ParseResult{std::move(result)};
 }
 
@@ -1506,20 +1515,22 @@ struct TorqueGrammar : Grammar {
   // Result: base::Optional<TypeList>
   Symbol* optionalGenericParameters = Optional<TypeList>(&genericParameters);
 
+  Symbol implicitParameterList{
+      Rule({Token("("), OneOf({"implicit", "js-implicit"}),
+            List<NameAndTypeExpression>(&nameAndType, Token(",")), Token(")")},
+           MakeImplicitParameterList)};
+
   Symbol* optionalImplicitParameterList{
-      TryOrDefault<std::vector<NameAndTypeExpression>>(
-          Sequence({Token("("), Token("implicit"),
-                    List<NameAndTypeExpression>(&nameAndType, Token(",")),
-                    Token(")")}))};
+      Optional<ImplicitParameters>(&implicitParameterList)};
 
   // Result: ParameterList
   Symbol typeListMaybeVarArgs = {
       Rule({optionalImplicitParameterList, Token("("),
             List<TypeExpression*>(Sequence({&type, Token(",")})), Token("..."),
             Token(")")},
-           MakeParameterListFromTypes<true>),
+           MakeParameterList<true, false>),
       Rule({optionalImplicitParameterList, Token("("), typeList, Token(")")},
-           MakeParameterListFromTypes<false>)};
+           MakeParameterList<false, false>)};
 
   // Result: LabelAndTypes
   Symbol labelParameter = {Rule(
@@ -1566,15 +1577,15 @@ struct TorqueGrammar : Grammar {
   Symbol parameterListNoVararg = {
       Rule({optionalImplicitParameterList, Token("("),
             List<NameAndTypeExpression>(&nameAndType, Token(",")), Token(")")},
-           MakeParameterListFromNameAndTypeList<false>)};
+           MakeParameterList<false, true>)};
 
   // Result: ParameterList
   Symbol parameterListAllowVararg = {
       Rule({&parameterListNoVararg}),
       Rule({optionalImplicitParameterList, Token("("),
-            NonemptyList<NameAndTypeExpression>(&nameAndType, Token(",")),
-            Token(","), Token("..."), &identifier, Token(")")},
-           MakeParameterListFromNameAndTypeList<true>)};
+            List<NameAndTypeExpression>(Sequence({&nameAndType, Token(",")})),
+            Token("..."), &identifier, Token(")")},
+           MakeParameterList<true, true>)};
 
   // Result: Identifier*
   Symbol* OneOf(const std::vector<std::string>& alternatives) {

src/torque/type-oracle.h

@@ -203,6 +203,14 @@ class TypeOracle : public ContextualClass<TypeOracle> {
     return Get().GetBuiltinType(CONST_INT32_TYPE_STRING);
   }
 
+  static const Type* GetContextType() {
+    return Get().GetBuiltinType(CONTEXT_TYPE_STRING);
+  }
+
+  static const Type* GetJSFunctionType() {
+    return Get().GetBuiltinType(JS_FUNCTION_TYPE_STRING);
+  }
+
   static bool IsImplicitlyConvertableFrom(const Type* to, const Type* from) {
     for (Generic* from_constexpr :
          Declarations::LookupGeneric(kFromConstexprMacroName)) {

src/torque/types.h

@@ -669,6 +669,7 @@ struct Signature {
   base::Optional<std::string> arguments_variable;
   ParameterTypes parameter_types;
   size_t implicit_count;
+  size_t ExplicitCount() const { return types().size() - implicit_count; }
   const Type* return_type;
   LabelDeclarationVector labels;
   bool HasSameTypesAs(

third_party/v8/builtins/array-sort.tq

@@ -1369,7 +1369,7 @@ namespace array {
 
   // https://tc39.github.io/ecma262/#sec-array.prototype.sort
   transitioning javascript builtin
-  ArrayPrototypeSort(context: Context, receiver: Object, ...arguments): Object {
+  ArrayPrototypeSort(js-implicit context: Context, receiver: Object)( ...arguments): Object {
     // 1. If comparefn is not undefined and IsCallable(comparefn) is false,
     //    throw a TypeError exception.
     const comparefnObj: Object = arguments[0];

tools/torque/format-torque.py

@@ -51,6 +51,7 @@ def preprocess(input):
       r'\1_OtheSaLi', input)
   input = re.sub(r'@if\(', r'@iF(', input)
   input = re.sub(r'@export', r'@eXpOrT', input)
+  input = re.sub(r'js-implicit[ \n]+', r'jS_iMpLiCiT_', input)
 
   # Special handing of '%' for intrinsics, turn the percent
   # into a unicode character so that it gets treated as part of the
@@ -88,6 +89,8 @@ def postprocess(output):
   output = re.sub(r'@iF\(', r'@if(', output)
   output = re.sub(r'@eXpOrT',
       r"@export", output)
+  output = re.sub(r'jS_iMpLiCiT_',
+      r"js-implicit ", output)
 
   while True:
     old = output

tools/torque/vim-torque/syntax/torque.vim

@@ -27,7 +27,7 @@ syn keyword torqueConditional if else typeswitch otherwise
 syn match torqueConstant /\v<[A-Z][A-Z0-9_]+>/
 syn match torqueConstant /\v<k[A-Z][A-Za-z0-9]*>/
 syn keyword torqueFunction macro builtin runtime intrinsic
-syn keyword torqueKeyword cast convert from_constexpr min max unsafe_cast
+syn keyword torqueKeyword cast convert from_constexpr min max unsafe_cast js-implicit implicit
 syn keyword torqueLabel case
 syn keyword torqueMatching try label catch
 syn keyword torqueModifier extern javascript constexpr transitioning transient weak export