[torque] cleanup CastHeapObject

Since the improvement of overload resolution (https://crrev.com/c/1304294),
overload resolution of generics doesn't take into account existing
specializations anymore. This means that the issue of infinite recursion
when an overload of Cast for HeapObject is missing doesn't exist anymore.
Thus we can get rid of the CastHeapObject workaround.

Bug: v8:7793
Change-Id: I8442cfb81b78aaa8234bcee673647261c25f9a63
Reviewed-on: https://chromium-review.googlesource.com/c/1448324
Reviewed-by: Daniel Clifford <danno@chromium.org>
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59263}

src/builtins/base.tq

@@ -661,103 +661,124 @@ extern macro HeapObjectToSloppyArgumentsElements(HeapObject):
 extern macro TaggedToNumber(Object): Number
     labels CastError;
 
-macro CastHeapObject<A: type>(o: HeapObject): A
+macro Cast<A: type>(implicit context: Context)(o: Object): A
+    labels CastError {
+  return Cast<A>(TaggedToHeapObject(o) otherwise CastError)
+      otherwise CastError;
+}
+
+Cast<Smi>(o: Object): Smi
+    labels CastError {
+  return TaggedToSmi(o) otherwise CastError;
+}
+
+Cast<PositiveSmi>(o: Object): PositiveSmi
+    labels CastError {
+  return TaggedToPositiveSmi(o) otherwise CastError;
+}
+
+Cast<Number>(o: Object): Number
+    labels CastError {
+  return TaggedToNumber(o) otherwise CastError;
+}
+
+macro Cast<A: type>(o: HeapObject): A
     labels CastError;
 
-CastHeapObject<HeapObject>(o: HeapObject): HeapObject
+Cast<HeapObject>(o: HeapObject): HeapObject
     labels CastError {
   return o;
 }
 
-CastHeapObject<FixedArray>(o: HeapObject): FixedArray
+Cast<FixedArray>(o: HeapObject): FixedArray
     labels CastError {
   return HeapObjectToFixedArray(o) otherwise CastError;
 }
 
-CastHeapObject<FixedDoubleArray>(o: HeapObject): FixedDoubleArray
+Cast<FixedDoubleArray>(o: HeapObject): FixedDoubleArray
     labels CastError {
   return HeapObjectToFixedDoubleArray(o) otherwise CastError;
 }
 
-CastHeapObject<SloppyArgumentsElements>(o: HeapObject): SloppyArgumentsElements
+Cast<SloppyArgumentsElements>(o: HeapObject): SloppyArgumentsElements
     labels CastError {
   return HeapObjectToSloppyArgumentsElements(o) otherwise CastError;
 }
 
-CastHeapObject<JSDataView>(o: HeapObject): JSDataView
+Cast<JSDataView>(o: HeapObject): JSDataView
     labels CastError {
   return HeapObjectToJSDataView(o) otherwise CastError;
 }
 
-CastHeapObject<JSTypedArray>(o: HeapObject): JSTypedArray
+Cast<JSTypedArray>(o: HeapObject): JSTypedArray
     labels CastError {
   if (IsJSTypedArray(o)) return %RawDownCast<JSTypedArray>(o);
   goto CastError;
 }
 
-CastHeapObject<Callable>(o: HeapObject): Callable
+Cast<Callable>(o: HeapObject): Callable
     labels CastError {
   return HeapObjectToCallable(o) otherwise CastError;
 }
 
-CastHeapObject<JSArray>(o: HeapObject): JSArray
+Cast<JSArray>(o: HeapObject): JSArray
     labels CastError {
   return HeapObjectToJSArray(o) otherwise CastError;
 }
 
-CastHeapObject<JSArrayBuffer>(o: HeapObject): JSArrayBuffer
+Cast<JSArrayBuffer>(o: HeapObject): JSArrayBuffer
     labels CastError {
   return HeapObjectToJSArrayBuffer(o) otherwise CastError;
 }
 
-CastHeapObject<Context>(o: HeapObject): Context
+Cast<Context>(o: HeapObject): Context
     labels CastError {
   if (IsContext(o)) return %RawDownCast<Context>(o);
   goto CastError;
 }
 
-CastHeapObject<JSObject>(o: HeapObject): JSObject
+Cast<JSObject>(o: HeapObject): JSObject
     labels CastError {
   if (IsJSObject(o)) return %RawDownCast<JSObject>(o);
   goto CastError;
 }
 
-CastHeapObject<NumberDictionary>(o: HeapObject): NumberDictionary
+Cast<NumberDictionary>(o: HeapObject): NumberDictionary
     labels CastError {
   if (IsNumberDictionary(o)) return %RawDownCast<NumberDictionary>(o);
   goto CastError;
 }
 
-CastHeapObject<FixedTypedArrayBase>(o: HeapObject): FixedTypedArrayBase
+Cast<FixedTypedArrayBase>(o: HeapObject): FixedTypedArrayBase
     labels CastError {
   if (IsFixedTypedArray(o)) return %RawDownCast<FixedTypedArrayBase>(o);
   goto CastError;
 }
 
-CastHeapObject<String>(o: HeapObject): String
+Cast<String>(o: HeapObject): String
     labels CastError {
   return HeapObjectToString(o) otherwise CastError;
 }
 
-CastHeapObject<Constructor>(o: HeapObject): Constructor
+Cast<Constructor>(o: HeapObject): Constructor
     labels CastError {
   return HeapObjectToConstructor(o) otherwise CastError;
 }
 
-CastHeapObject<HeapNumber>(o: HeapObject): HeapNumber
+Cast<HeapNumber>(o: HeapObject): HeapNumber
     labels CastError {
   if (IsHeapNumber(o)) return %RawDownCast<HeapNumber>(o);
   goto CastError;
 }
 
-CastHeapObject<Map>(implicit context: Context)(o: HeapObject): Map
+Cast<Map>(implicit context: Context)(o: HeapObject): Map
     labels CastError {
   if (IsMap(o)) return %RawDownCast<Map>(o);
   goto CastError;
 }
 
-CastHeapObject<JSArgumentsObjectWithLength>(implicit context: Context)(
-    o: HeapObject): JSArgumentsObjectWithLength
+Cast<JSArgumentsObjectWithLength>(implicit context: Context)(o: HeapObject):
+    JSArgumentsObjectWithLength
     labels CastError {
   const map: Map = o.map;
   try {
@@ -772,8 +793,7 @@ CastHeapObject<JSArgumentsObjectWithLength>(implicit context: Context)(
   }
 }
 
-CastHeapObject<FastJSArray>(implicit context: Context)(o: HeapObject):
-    FastJSArray
+Cast<FastJSArray>(implicit context: Context)(o: HeapObject): FastJSArray
     labels CastError {
   const map: Map = o.map;
   if (!IsJSArrayMap(map)) goto CastError;
@@ -816,7 +836,7 @@ struct FastJSArrayWitness {
   map: Map;
 }
 
-CastHeapObject<FastJSArrayForCopy>(implicit context: Context)(o: HeapObject):
+Cast<FastJSArrayForCopy>(implicit context: Context)(o: HeapObject):
     FastJSArrayForCopy
     labels CastError {
   if (IsArraySpeciesProtectorCellInvalid()) goto CastError;
@@ -824,7 +844,7 @@ CastHeapObject<FastJSArrayForCopy>(implicit context: Context)(o: HeapObject):
   return %RawDownCast<FastJSArrayForCopy>(o);
 }
 
-CastHeapObject<FastJSArrayWithNoCustomIteration>(implicit context: Context)(
+Cast<FastJSArrayWithNoCustomIteration>(implicit context: Context)(
     o: HeapObject): FastJSArrayWithNoCustomIteration
     labels CastError {
   if (IsArrayIteratorProtectorCellInvalid()) goto CastError;
@@ -832,46 +852,18 @@ CastHeapObject<FastJSArrayWithNoCustomIteration>(implicit context: Context)(
   return %RawDownCast<FastJSArrayWithNoCustomIteration>(o);
 }
 
-CastHeapObject<JSReceiver>(implicit context: Context)(o: HeapObject): JSReceiver
+Cast<JSReceiver>(implicit context: Context)(o: HeapObject): JSReceiver
     labels CastError {
   if (IsJSReceiver(o)) return %RawDownCast<JSReceiver>(o);
   goto CastError;
 }
 
-CastHeapObject<JSFunction>(implicit context: Context)(o: HeapObject): JSFunction
+Cast<JSFunction>(implicit context: Context)(o: HeapObject): JSFunction
     labels CastError {
   if (IsJSFunction(o)) return %RawDownCast<JSFunction>(o);
   goto CastError;
 }
 
-macro Cast<A: type>(implicit context: Context)(o: HeapObject): A
-    labels CastError {
-  return CastHeapObject<A>(o) otherwise CastError;
-}
-
-// CastHeapObject allows this default-implementation to be non-recursive.
-// Otherwise the generated CSA code might run into infinite recursion.
-macro Cast<A: type>(implicit context: Context)(o: Object): A
-    labels CastError {
-  return CastHeapObject<A>(TaggedToHeapObject(o) otherwise CastError)
-      otherwise CastError;
-}
-
-Cast<Smi>(o: Object): Smi
-    labels CastError {
-  return TaggedToSmi(o) otherwise CastError;
-}
-
-Cast<PositiveSmi>(o: Object): PositiveSmi
-    labels CastError {
-  return TaggedToPositiveSmi(o) otherwise CastError;
-}
-
-Cast<Number>(o: Object): Number
-    labels CastError {
-  return TaggedToNumber(o) otherwise CastError;
-}
-
 extern macro AllocateHeapNumberWithValue(float64): HeapNumber;
 extern macro ChangeInt32ToTagged(int32): Number;
 extern macro ChangeUint32ToTagged(uint32): Number;