Bug 1343481 - Part 7: Add BytecodeEmitter::emitDotGenerator and make yield/await nodes unary.

Tag #1287

11 files changed, 124 insertions, 112 deletions

diff --git a/js/src/builtin/ReflectParse.cpp b/js/src/builtin/ReflectParse.cpp
index 120970196a..22c958d4ca 100644
--- a/js/src/builtin/ReflectParse.cpp
+++ b/js/src/builtin/ReflectParse.cpp
@@ -2800,11 +2800,11 @@ ASTSerializer::generatorExpression(ParseNode* pn, MutableHandleValue dst)
 
     LOCAL_ASSERT(next->isKind(PNK_SEMI) &&
                  next->pn_kid->isKind(PNK_YIELD) &&
-                 next->pn_kid->pn_left);
+                 next->pn_kid->pn_kid);
 
     RootedValue body(cx);
 
-    return expression(next->pn_kid->pn_left, &body) &&
+    return expression(next->pn_kid->pn_kid, &body) &&
            builder.generatorExpression(body, blocks, filter, isLegacy, &pn->pn_pos, dst);
 }
 
@@ -3146,7 +3146,7 @@ ASTSerializer::expression(ParseNode* pn, MutableHandleValue dst)
 
       case PNK_YIELD_STAR:
       {
-        MOZ_ASSERT(pn->pn_pos.encloses(pn->pn_left->pn_pos));
+        MOZ_ASSERT(pn->pn_pos.encloses(pn->pn_kid->pn_pos));
 
         RootedValue arg(cx);
         return expression(pn->pn_left, &arg) &&
@@ -3155,10 +3155,10 @@ ASTSerializer::expression(ParseNode* pn, MutableHandleValue dst)
 
       case PNK_YIELD:
       {
-        MOZ_ASSERT_IF(pn->pn_left, pn->pn_pos.encloses(pn->pn_left->pn_pos));
+        MOZ_ASSERT_IF(pn->pn_kid, pn->pn_pos.encloses(pn->pn_kid->pn_pos));
 
         RootedValue arg(cx);
-        return optExpression(pn->pn_left, &arg) &&
+        return optExpression(pn->pn_kid, &arg) &&
                builder.yieldExpression(arg, NotDelegating, &pn->pn_pos, dst);
       }
 
@@ -3480,7 +3480,7 @@ ASTSerializer::functionArgsAndBody(ParseNode* pn, NodeVector& args, NodeVector&
         ParseNode* pnstart = pnbody->pn_head;
 
         // Skip over initial yield in generator.
-        if (pnstart && pnstart->isKind(PNK_YIELD)) {
+        if (pnstart && pnstart->isKind(PNK_INITIALYIELD)) {
             MOZ_ASSERT(pnstart->getOp() == JSOP_INITIALYIELD);
             pnstart = pnstart->pn_next;
         }
diff --git a/js/src/frontend/BytecodeEmitter.cpp b/js/src/frontend/BytecodeEmitter.cpp
index 6a6deed12f..77a480bff6 100644
--- a/js/src/frontend/BytecodeEmitter.cpp
+++ b/js/src/frontend/BytecodeEmitter.cpp
@@ -3175,10 +3175,11 @@ BytecodeEmitter::checkSideEffects(ParseNode* pn, bool* answer)
         *answer = true;
         return true;
 
+      case PNK_INITIALYIELD:
       case PNK_YIELD_STAR:
       case PNK_YIELD:
       case PNK_AWAIT:
-        MOZ_ASSERT(pn->isArity(PN_BINARY));
+        MOZ_ASSERT(pn->isArity(PN_UNARY));
         *answer = true;
         return true;
 
@@ -8526,45 +8527,61 @@ BytecodeEmitter::emitReturn(ParseNode* pn)
 }
 
 bool
+BytecodeEmitter::emitGetDotGenerator()
+{
+    NameLocation loc = *locationOfNameBoundInFunctionScope(cx->names().dotGenerator);
+    return emitGetNameAtLocation(cx->names().dotGenerator, loc);
+}
+
+bool
+BytecodeEmitter::emitInitialYield(ParseNode* pn)
+{
+    if (!emitTree(pn->pn_kid))
+        return false;
+
+    if (!emitYieldOp(JSOP_INITIALYIELD))
+        return false;
+
+    if (!emit1(JSOP_POP))
+        return false;
+
+    return true;
+}
+
+bool
 BytecodeEmitter::emitYield(ParseNode* pn)
 {
     MOZ_ASSERT(sc->isFunctionBox());
+    MOZ_ASSERT(pn->getOp() == JSOP_YIELD || pn->getOp() == JSOP_AWAIT);
 
-    if (pn->getOp() == JSOP_YIELD || pn->getOp() == JSOP_AWAIT) {
-        bool needsIteratorResult = sc->asFunctionBox()->needsIteratorResult();
-        if (needsIteratorResult) {
-            if (!emitPrepareIteratorResult())
-                return false;
-        }
-        if (pn->pn_left) {
-            if (!emitTree(pn->pn_left))
-                return false;
-        } else {
-            if (!emit1(JSOP_UNDEFINED))
-                return false;
-        }
-        if (needsIteratorResult) {
-            if (!emitFinishIteratorResult(false))
-                return false;
-        }
+    bool needsIteratorResult = sc->asFunctionBox()->needsIteratorResult();
+    if (needsIteratorResult) {
+        if (!emitPrepareIteratorResult())
+            return false;
+    }
+    if (pn->pn_kid) {
+        if (!emitTree(pn->pn_kid))
+            return false;
     } else {
-        MOZ_ASSERT(pn->getOp() == JSOP_INITIALYIELD);
+        if (!emit1(JSOP_UNDEFINED))
+            return false;
+    }
+    if (needsIteratorResult) {
+        if (!emitFinishIteratorResult(false))
+            return false;
     }
 
-    if (!emitTree(pn->pn_right))
+    if (!emitGetDotGenerator())
         return false;
 
     if (!emitYieldOp(pn->getOp()))
         return false;
 
-    if (pn->getOp() == JSOP_INITIALYIELD && !emit1(JSOP_POP))
-        return false;
-
     return true;
 }
 
 bool
-BytecodeEmitter::emitYieldStar(ParseNode* iter, ParseNode* gen)
+BytecodeEmitter::emitYieldStar(ParseNode* iter)
 {
     MOZ_ASSERT(sc->isFunctionBox());
     MOZ_ASSERT(sc->asFunctionBox()->isStarGenerator());
@@ -8594,7 +8611,7 @@ BytecodeEmitter::emitYieldStar(ParseNode* iter, ParseNode* gen)
     MOZ_ASSERT(this->stackDepth == startDepth);
 
     // Load the generator object.
-    if (!emitTree(gen))                                   // ITER RESULT GENOBJ
+    if (!emitGetDotGenerator())                           // ITER RESULT GENOBJ
         return false;
 
     // Yield RESULT as-is, without re-boxing.
@@ -10338,8 +10355,7 @@ BytecodeEmitter::emitFunctionBody(ParseNode* funBody)
         if (!emit1(JSOP_SETRVAL))
             return false;
 
-        NameLocation loc = *locationOfNameBoundInFunctionScope(cx->names().dotGenerator);
-        if (!emitGetNameAtLocation(cx->names().dotGenerator, loc))
+        if (!emitGetDotGenerator())
             return false;
 
         // No need to check for finally blocks, etc as in EmitReturn.
@@ -10599,7 +10615,7 @@ BytecodeEmitter::emitTree(ParseNode* pn, ValueUsage valueUsage /* = ValueUsage::
         break;
 
       case PNK_YIELD_STAR:
-        if (!emitYieldStar(pn->pn_left, pn->pn_right))
+        if (!emitYieldStar(pn->pn_kid))
             return false;
         break;
 
@@ -10608,6 +10624,11 @@ BytecodeEmitter::emitTree(ParseNode* pn, ValueUsage valueUsage /* = ValueUsage::
             return false;
         break;
 
+      case PNK_INITIALYIELD:
+        if (!emitInitialYield(pn))
+            return false;
+        break;
+
       case PNK_YIELD:
       case PNK_AWAIT:
         if (!emitYield(pn))
diff --git a/js/src/frontend/BytecodeEmitter.h b/js/src/frontend/BytecodeEmitter.h
index 7f2dddfed1..08638f48a7 100644
--- a/js/src/frontend/BytecodeEmitter.h
+++ b/js/src/frontend/BytecodeEmitter.h
@@ -607,9 +607,12 @@ struct MOZ_STACK_CLASS BytecodeEmitter
     MOZ_MUST_USE bool emitFinishIteratorResult(bool done);
     MOZ_MUST_USE bool iteratorResultShape(unsigned* shape);
 
+    MOZ_MUST_USE bool emitGetDotGenerator();
+
+    MOZ_MUST_USE bool emitInitialYield(ParseNode* pn);
     MOZ_MUST_USE bool emitYield(ParseNode* pn);
     MOZ_MUST_USE bool emitYieldOp(JSOp op);
-    MOZ_MUST_USE bool emitYieldStar(ParseNode* iter, ParseNode* gen);
+    MOZ_MUST_USE bool emitYieldStar(ParseNode* iter);
 
     MOZ_MUST_USE bool emitPropLHS(ParseNode* pn);
     MOZ_MUST_USE bool emitPropOp(ParseNode* pn, JSOp op);
diff --git a/js/src/frontend/FoldConstants.cpp b/js/src/frontend/FoldConstants.cpp
index 689fa02b4b..16294c4a81 100644
--- a/js/src/frontend/FoldConstants.cpp
+++ b/js/src/frontend/FoldConstants.cpp
@@ -117,9 +117,10 @@ ContainsHoistedDeclaration(ExclusiveContext* cx, ParseNode* node, bool* result)
 
       // These two aren't statements in the spec, but we sometimes insert them
       // in statement lists anyway.
+      case PNK_INITIALYIELD:
       case PNK_YIELD_STAR:
       case PNK_YIELD:
-        MOZ_ASSERT(node->isArity(PN_BINARY));
+        MOZ_ASSERT(node->isArity(PN_UNARY));
         *result = false;
         return true;
 
@@ -1775,21 +1776,23 @@ Fold(ExclusiveContext* cx, ParseNode** pnp, Parser<FullParseHandler>& parser, bo
       case PNK_GENEXP:
         return FoldList(cx, pn, parser, inGenexpLambda);
 
+      case PNK_INITIALYIELD:
+        MOZ_ASSERT(pn->isArity(PN_UNARY));
+        MOZ_ASSERT(pn->pn_kid->isKind(PNK_ASSIGN) &&
+                   pn->pn_kid->pn_left->isKind(PNK_NAME) &&
+                   pn->pn_kid->pn_right->isKind(PNK_GENERATOR));
+        return true;
+
       case PNK_YIELD_STAR:
-        MOZ_ASSERT(pn->isArity(PN_BINARY));
-        MOZ_ASSERT(pn->pn_right->isKind(PNK_NAME));
-        return Fold(cx, &pn->pn_left, parser, inGenexpLambda);
+        MOZ_ASSERT(pn->isArity(PN_UNARY));
+        return Fold(cx, &pn->pn_kid, parser, inGenexpLambda);
 
       case PNK_YIELD:
       case PNK_AWAIT:
-        MOZ_ASSERT(pn->isArity(PN_BINARY));
-        MOZ_ASSERT(pn->pn_right->isKind(PNK_NAME) ||
-                   (pn->pn_right->isKind(PNK_ASSIGN) &&
-                    pn->pn_right->pn_left->isKind(PNK_NAME) &&
-                    pn->pn_right->pn_right->isKind(PNK_GENERATOR)));
-        if (!pn->pn_left)
+        MOZ_ASSERT(pn->isArity(PN_UNARY));
+        if (!pn->pn_kid)
             return true;
-        return Fold(cx, &pn->pn_left, parser, inGenexpLambda);
+        return Fold(cx, &pn->pn_kid, parser, inGenexpLambda);
 
       case PNK_RETURN:
         return FoldReturn(cx, pn, parser, inGenexpLambda);
diff --git a/js/src/frontend/FullParseHandler.h b/js/src/frontend/FullParseHandler.h
index 6ab93f3f9d..44694298bd 100644
--- a/js/src/frontend/FullParseHandler.h
+++ b/js/src/frontend/FullParseHandler.h
@@ -440,20 +440,24 @@ class FullParseHandler
         return true;
     }
 
-    ParseNode* newYieldExpression(uint32_t begin, ParseNode* value, ParseNode* gen,
-                                  JSOp op = JSOP_YIELD) {
+    ParseNode* newInitialYieldExpression(uint32_t begin, ParseNode* gen) {
+        TokenPos pos(begin, begin + 1);
+        return new_<UnaryNode>(PNK_INITIALYIELD, JSOP_INITIALYIELD, pos, gen);
+    }
+
+    ParseNode* newYieldExpression(uint32_t begin, ParseNode* value) {
         TokenPos pos(begin, value ? value->pn_pos.end : begin + 1);
-        return new_<BinaryNode>(PNK_YIELD, op, pos, value, gen);
+        return new_<UnaryNode>(PNK_YIELD, JSOP_YIELD, pos, value);
     }
 
-    ParseNode* newYieldStarExpression(uint32_t begin, ParseNode* value, ParseNode* gen) {
+    ParseNode* newYieldStarExpression(uint32_t begin, ParseNode* value) {
         TokenPos pos(begin, value->pn_pos.end);
-        return new_<BinaryNode>(PNK_YIELD_STAR, JSOP_NOP, pos, value, gen);
+        return new_<UnaryNode>(PNK_YIELD_STAR, JSOP_NOP, pos, value);
     }
 
-    ParseNode* newAwaitExpression(uint32_t begin, ParseNode* value, ParseNode* gen) {
+    ParseNode* newAwaitExpression(uint32_t begin, ParseNode* value) {
         TokenPos pos(begin, value ? value->pn_pos.end : begin + 1);
-        return new_<BinaryNode>(PNK_AWAIT, JSOP_AWAIT, pos, value, gen);
+        return new_<UnaryNode>(PNK_AWAIT, JSOP_AWAIT, pos, value);
     }
 
     // Statements
@@ -506,8 +510,7 @@ class FullParseHandler
         if (!genInit)
             return false;
 
-        ParseNode* initialYield = newYieldExpression(yieldPos.begin, nullptr, genInit,
-                                                     JSOP_INITIALYIELD);
+        ParseNode* initialYield = newInitialYieldExpression(yieldPos.begin, genInit);
         if (!initialYield)
             return false;
 
diff --git a/js/src/frontend/NameFunctions.cpp b/js/src/frontend/NameFunctions.cpp
index dc54d0a88f..376be76242 100644
--- a/js/src/frontend/NameFunctions.cpp
+++ b/js/src/frontend/NameFunctions.cpp
@@ -501,24 +501,25 @@ class NameResolver
                 return false;
             break;
 
+          case PNK_INITIALYIELD:
+            MOZ_ASSERT(cur->pn_kid->isKind(PNK_ASSIGN) &&
+                       cur->pn_kid->pn_left->isKind(PNK_NAME) &&
+                       cur->pn_kid->pn_right->isKind(PNK_GENERATOR));
+            break;
+
           case PNK_YIELD_STAR:
-            MOZ_ASSERT(cur->isArity(PN_BINARY));
-            MOZ_ASSERT(cur->pn_right->isKind(PNK_NAME));
-            if (!resolve(cur->pn_left, prefix))
+            MOZ_ASSERT(cur->isArity(PN_UNARY));
+            if (!resolve(cur->pn_kid, prefix))
                 return false;
             break;
 
           case PNK_YIELD:
           case PNK_AWAIT:
-            MOZ_ASSERT(cur->isArity(PN_BINARY));
-            if (cur->pn_left) {
-                if (!resolve(cur->pn_left, prefix))
+            MOZ_ASSERT(cur->isArity(PN_UNARY));
+            if (cur->pn_kid) {
+                if (!resolve(cur->pn_kid, prefix))
                     return false;
             }
-            MOZ_ASSERT(cur->pn_right->isKind(PNK_NAME) ||
-                       (cur->pn_right->isKind(PNK_ASSIGN) &&
-                        cur->pn_right->pn_left->isKind(PNK_NAME) &&
-                        cur->pn_right->pn_right->isKind(PNK_GENERATOR)));
             break;
 
           case PNK_RETURN:
diff --git a/js/src/frontend/ParseNode.cpp b/js/src/frontend/ParseNode.cpp
index 5fe64e3d36..42ae9451a3 100644
--- a/js/src/frontend/ParseNode.cpp
+++ b/js/src/frontend/ParseNode.cpp
@@ -286,22 +286,24 @@ PushNodeChildren(ParseNode* pn, NodeStack* stack)
         return PushResult::Recyclable;
       }
 
-      // The left half is the expression being yielded.  The right half is
-      // internal goop: a name reference to the invisible '.generator' local
-      // variable, or an assignment of a PNK_GENERATOR node to the '.generator'
-      // local, for a synthesized, prepended initial yield.  Yum!
+      // The child is an assignment of a PNK_GENERATOR node to the
+      // '.generator' local, for a synthesized, prepended initial yield.
+      case PNK_INITIALYIELD: {
+        MOZ_ASSERT(pn->isArity(PN_UNARY));
+        MOZ_ASSERT(pn->pn_kid->isKind(PNK_ASSIGN) &&
+                   pn->pn_kid->pn_left->isKind(PNK_NAME) &&
+                   pn->pn_kid->pn_right->isKind(PNK_GENERATOR));
+        stack->push(pn->pn_kid);
+        return PushResult::Recyclable;
+      }
+
+      // The child is the expression being yielded.
       case PNK_YIELD_STAR:
       case PNK_YIELD:
       case PNK_AWAIT: {
-        MOZ_ASSERT(pn->isArity(PN_BINARY));
-        MOZ_ASSERT(pn->pn_right);
-        MOZ_ASSERT(pn->pn_right->isKind(PNK_NAME) ||
-                   (pn->pn_right->isKind(PNK_ASSIGN) &&
-                    pn->pn_right->pn_left->isKind(PNK_NAME) &&
-                    pn->pn_right->pn_right->isKind(PNK_GENERATOR)));
-        if (pn->pn_left)
-            stack->push(pn->pn_left);
-        stack->push(pn->pn_right);
+        MOZ_ASSERT(pn->isArity(PN_UNARY));
+        if (pn->pn_kid)
+            stack->push(pn->pn_kid);
         return PushResult::Recyclable;
       }
 
diff --git a/js/src/frontend/ParseNode.h b/js/src/frontend/ParseNode.h
index 1f20f39887..9a435e2701 100644
--- a/js/src/frontend/ParseNode.h
+++ b/js/src/frontend/ParseNode.h
@@ -83,6 +83,7 @@ class ObjectBox;
     F(THROW) \
     F(DEBUGGER) \
     F(GENERATOR) \
+    F(INITIALYIELD) \
     F(YIELD) \
     F(YIELD_STAR) \
     F(GENEXP) \
@@ -418,8 +419,9 @@ IsTypeofKind(ParseNodeKind kind)
  * PNK_LEXICALSCOPE scope   pn_u.scope.bindings: scope bindings
  *                          pn_u.scope.body: scope body
  * PNK_GENERATOR    nullary
- * PNK_YIELD,       binary  pn_left: expr or null; pn_right: generator object
- * PNK_YIELD_STAR
+ * PNK_INITIALYIELD unary   pn_kid: generator object
+ * PNK_YIELD,       unary   pn_kid: expr or null
+ * PNK_YIELD_STAR,
  * PNK_ARRAYCOMP    list    pn_count: 1
  *                          pn_head: list of 1 element, which is block
  *                          enclosing for loop(s) and optionally
diff --git a/js/src/frontend/Parser.cpp b/js/src/frontend/Parser.cpp
index 406d377258..3ae5890ac5 100644
--- a/js/src/frontend/Parser.cpp
+++ b/js/src/frontend/Parser.cpp
@@ -6548,29 +6548,6 @@ Parser<ParseHandler>::returnStatement(YieldHandling yieldHandling)
 
 template <typename ParseHandler>
 typename ParseHandler::Node
-Parser<ParseHandler>::newYieldExpression(uint32_t begin, typename ParseHandler::Node expr,
-                                         bool isYieldStar)
-{
-    Node generator = newDotGeneratorName();
-    if (!generator)
-        return null();
-    if (isYieldStar)
-        return handler.newYieldStarExpression(begin, expr, generator);
-    return handler.newYieldExpression(begin, expr, generator);
-}
-
-template <typename ParseHandler>
-typename ParseHandler::Node
-Parser<ParseHandler>::newAwaitExpression(uint32_t begin, typename ParseHandler::Node expr)
-{
-    Node generator = newDotGeneratorName();
-    if (!generator)
-        return null();
-    return handler.newAwaitExpression(begin, expr, generator);
-}
-
-template <typename ParseHandler>
-typename ParseHandler::Node
 Parser<ParseHandler>::yieldExpression(InHandling inHandling)
 {
     MOZ_ASSERT(tokenStream.isCurrentTokenType(TOK_YIELD));
@@ -6617,7 +6594,9 @@ Parser<ParseHandler>::yieldExpression(InHandling inHandling)
             if (!exprNode)
                 return null();
         }
-        return newYieldExpression(begin, exprNode, kind == PNK_YIELD_STAR);
+        if (kind == PNK_YIELD_STAR)
+            return handler.newYieldStarExpression(begin, exprNode);
+        return handler.newYieldExpression(begin, exprNode);
       }
 
       case NotGenerator:
@@ -6694,7 +6673,7 @@ Parser<ParseHandler>::yieldExpression(InHandling inHandling)
                 return null();
         }
 
-        return newYieldExpression(begin, exprNode);
+        return handler.newYieldExpression(begin, exprNode);
       }
     }
 
@@ -8449,7 +8428,7 @@ Parser<ParseHandler>::unaryExpr(YieldHandling yieldHandling, TripledotHandling t
             if (!kid)
                 return null();
             pc->lastAwaitOffset = begin;
-            return newAwaitExpression(begin, kid);
+            return handler.newAwaitExpression(begin, kid);
         }
       }
 
@@ -8707,7 +8686,7 @@ Parser<ParseHandler>::comprehensionTail(GeneratorKind comprehensionKind)
         return handler.newArrayPush(begin, bodyExpr);
 
     MOZ_ASSERT(comprehensionKind == StarGenerator);
-    Node yieldExpr = newYieldExpression(begin, bodyExpr);
+    Node yieldExpr = handler.newYieldExpression(begin, bodyExpr);
     if (!yieldExpr)
         return null();
     yieldExpr = handler.parenthesize(yieldExpr);
diff --git a/js/src/frontend/Parser.h b/js/src/frontend/Parser.h
index 33fe345d63..73c2817f45 100644
--- a/js/src/frontend/Parser.h
+++ b/js/src/frontend/Parser.h
@@ -1110,8 +1110,6 @@ class Parser final : public ParserBase, private JS::AutoGCRooter
 
     inline Node newName(PropertyName* name);
     inline Node newName(PropertyName* name, TokenPos pos);
-    inline Node newYieldExpression(uint32_t begin, Node expr, bool isYieldStar = false);
-    inline Node newAwaitExpression(uint32_t begin, Node expr);
 
     inline bool abortIfSyntaxParser();
 
diff --git a/js/src/frontend/SyntaxParseHandler.h b/js/src/frontend/SyntaxParseHandler.h
index a604b599fb..d919f1354d 100644
--- a/js/src/frontend/SyntaxParseHandler.h
+++ b/js/src/frontend/SyntaxParseHandler.h
@@ -301,9 +301,9 @@ class SyntaxParseHandler
     MOZ_MUST_USE bool addSpreadProperty(Node literal, uint32_t begin, Node inner) { return true; }
     MOZ_MUST_USE bool addObjectMethodDefinition(Node literal, Node name, Node fn, JSOp op) { return true; }
     MOZ_MUST_USE bool addClassMethodDefinition(Node literal, Node name, Node fn, JSOp op, bool isStatic) { return true; }
-    Node newYieldExpression(uint32_t begin, Node value, Node gen) { return NodeGeneric; }
-    Node newYieldStarExpression(uint32_t begin, Node value, Node gen) { return NodeGeneric; }
-    Node newAwaitExpression(uint32_t begin, Node value, Node gen) { return NodeGeneric; }
+    Node newYieldExpression(uint32_t begin, Node value) { return NodeGeneric; }
+    Node newYieldStarExpression(uint32_t begin, Node value) { return NodeGeneric; }
+    Node newAwaitExpression(uint32_t begin, Node value) { return NodeGeneric; }
 
     // Statements