[class] Initialize class fields after binding this

Class fields needs to be initialized after `this` is bound, as per the
new spec change:
https://github.com/tc39/proposal-class-fields/pull/92

This CL moves the initialization of `this` from parser desugaring to
the bytecode generator.

Bug: v8:7647
Change-Id: I20f749403e5a4d2f06a39726cf39012ceb541987
Reviewed-on: https://chromium-review.googlesource.com/1014383Reviewed-by: Mythri Alle <mythria@chromium.org>
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52646}

src/interpreter/bytecode-generator.cc

@@ -3639,6 +3639,16 @@ void BytecodeGenerator::VisitCallSuper(Call* expr) {
     }
   }
 
+  // Explicit calls to the super constructor using super() perform an
+  // implicit binding assignment to the 'this' variable.
+  //
+  // Default constructors don't need have to do the assignment because
+  // 'this' isn't accessed in default constructors.
+  if (!IsDefaultConstructor(info()->literal()->kind())) {
+    BuildVariableAssignment(super->this_var()->var(), Token::INIT,
+                            HoleCheckMode::kRequired);
+  }
+
   // The derived constructor has the correct bit set always, so we
   // don't emit code to load and call the initializer if not
   // required.

src/parsing/parser-base.h

@@ -3424,24 +3424,12 @@ ParserBase<Impl>::ParseLeftHandSideExpression(bool* ok) {
         Call::PossiblyEval is_possibly_eval =
             CheckPossibleEvalCall(result, scope());
 
-        bool is_super_call = result->IsSuperCallReference();
         if (spread_pos.IsValid()) {
           result = impl()->SpreadCall(result, args, pos, is_possibly_eval);
         } else {
           result = factory()->NewCall(result, args, pos, is_possibly_eval);
         }
 
-        // Explicit calls to the super constructor using super() perform an
-        // implicit binding assignment to the 'this' variable.
-        if (is_super_call) {
-          classifier()->RecordAssignmentPatternError(
-              Scanner::Location(pos, scanner()->location().end_pos),
-              MessageTemplate::kInvalidDestructuringTarget);
-          ExpressionT this_expr = impl()->ThisExpression(pos);
-          result =
-              factory()->NewAssignment(Token::INIT, this_expr, result, pos);
-        }
-
         if (fni_ != nullptr) fni_->RemoveLastFunction();
         break;
       }

test/cctest/interpreter/bytecode_expectations/ClassAndSuperClass.golden

@@ -104,7 +104,7 @@ snippet: "
     test = new B().constructor;
   })();
 "
-frame size: 5
+frame size: 6
 parameter count: 1
 bytecode array length: 40
 bytecodes: [
@@ -116,14 +116,14 @@ bytecodes: [
                 B(Star), R(4),
                 B(Ldar), R(0),
   /*  118 E> */ B(Construct), R(3), R(4), U8(1), U8(0),
-                B(Star), R(2),
+                B(Star), R(5),
                 B(Ldar), R(this),
-  /*  118 E> */ B(ThrowSuperAlreadyCalledIfNotHole),
-                B(Mov), R(2), R(this),
+                B(ThrowSuperAlreadyCalledIfNotHole),
+                B(Mov), R(5), R(this),
   /*  128 S> */ B(Ldar), R(this),
                 B(ThrowSuperNotCalledIfHole),
                 B(LdaSmi), I8(2),
-  /*  136 E> */ B(StaNamedProperty), R(2), U8(0), U8(2),
+  /*  136 E> */ B(StaNamedProperty), R(this), U8(0), U8(2),
                 B(Ldar), R(this),
                 B(ThrowSuperNotCalledIfHole),
   /*  141 S> */ B(Return),
@@ -147,7 +147,7 @@ snippet: "
     test = new B().constructor;
   })();
 "
-frame size: 4
+frame size: 5
 parameter count: 1
 bytecode array length: 36
 bytecodes: [
@@ -157,14 +157,14 @@ bytecodes: [
                 B(GetSuperConstructor), R(3),
                 B(Ldar), R(0),
   /*  117 E> */ B(Construct), R(3), R(0), U8(0), U8(0),
-                B(Star), R(2),
+                B(Star), R(4),
                 B(Ldar), R(this),
-  /*  117 E> */ B(ThrowSuperAlreadyCalledIfNotHole),
-                B(Mov), R(2), R(this),
+                B(ThrowSuperAlreadyCalledIfNotHole),
+                B(Mov), R(4), R(this),
   /*  126 S> */ B(Ldar), R(this),
                 B(ThrowSuperNotCalledIfHole),
                 B(LdaSmi), I8(2),
-  /*  134 E> */ B(StaNamedProperty), R(2), U8(0), U8(2),
+  /*  134 E> */ B(StaNamedProperty), R(this), U8(0), U8(2),
                 B(Ldar), R(this),
                 B(ThrowSuperNotCalledIfHole),
   /*  139 S> */ B(Return),

test/cctest/interpreter/bytecode_expectations/SuperCallAndSpread.golden

@@ -49,7 +49,7 @@ snippet: "
     test = new B(1, 2, 3).constructor;
   })();
 "
-frame size: 8
+frame size: 9
 parameter count: 1
 bytecode array length: 40
 bytecodes: [
@@ -65,10 +65,10 @@ bytecodes: [
                 B(Ldar), R(0),
                 B(Mov), R(2), R(7),
   /*  140 E> */ B(ConstructWithSpread), R(5), R(6), U8(2), U8(0),
-                B(Star), R(4),
+                B(Star), R(8),
                 B(Ldar), R(this),
-  /*  140 E> */ B(ThrowSuperAlreadyCalledIfNotHole),
-                B(Mov), R(4), R(this),
+                B(ThrowSuperAlreadyCalledIfNotHole),
+                B(Mov), R(8), R(this),
                 B(Ldar), R(this),
                 B(ThrowSuperNotCalledIfHole),
   /*  159 S> */ B(Return),
@@ -142,10 +142,10 @@ bytecodes: [
                 B(Mov), R(6), R(9),
                 B(Mov), R(0), R(10),
   /*  140 E> */ B(CallJSRuntime), U8(%reflect_construct), R(8), U8(3),
-                B(Star), R(4),
+                B(Star), R(11),
                 B(Ldar), R(this),
-  /*  140 E> */ B(ThrowSuperAlreadyCalledIfNotHole),
-                B(Mov), R(4), R(this),
+                B(ThrowSuperAlreadyCalledIfNotHole),
+                B(Mov), R(11), R(this),
                 B(Ldar), R(this),
                 B(ThrowSuperNotCalledIfHole),
   /*  162 S> */ B(Return),

test/mjsunit/harmony/public-instance-class-fields.js

@@ -507,7 +507,7 @@ x()();
   }
 
   assertThrows(() => new C1, ReferenceError);
-  assertEquals([1,1], log);
+  assertEquals([1], log);
 
   log = [];
   class C2 extends class {} {
@@ -520,7 +520,7 @@ x()();
   }
 
   assertThrows(() => new C2, ReferenceError);
-  assertEquals([1,1], log);
+  assertEquals([1], log);
 }
 
 {
@@ -696,3 +696,21 @@ x()();
   let x = new X;
   assertEquals(1, x.p);
 }
+
+{
+  let thisInInitializer, thisInConstructor, thisFromArrowFn, arrowFn;
+  let C = class extends class {} {
+    field = (thisInInitializer = this, thisFromArrowFn = arrowFn());
+    constructor() {
+      arrowFn = () => this;
+      super();
+      thisInConstructor = this;
+    }
+  };
+
+  let c = new C();
+
+  assertSame(thisInInitializer, c);
+  assertSame(thisFromArrowFn, c);
+  assertSame(thisInConstructor, c);
+}