1315815 - Don't treat async or await as a keyword when they contain escapes.

3 files changed, 80 insertions, 64 deletions

diff --git a/js/src/frontend/FullParseHandler.h b/js/src/frontend/FullParseHandler.h
index b619cf24c..3938d9743 100644
--- a/js/src/frontend/FullParseHandler.h
+++ b/js/src/frontend/FullParseHandler.h
@@ -10,6 +10,8 @@
 #include "mozilla/Attributes.h"
 #include "mozilla/PodOperations.h"
 
+#include <string.h>
+
 #include "frontend/ParseNode.h"
 #include "frontend/SharedContext.h"
 
@@ -870,29 +872,25 @@ class FullParseHandler
         return node->isKind(PNK_NAME);
     }
 
-    bool nameIsEvalAnyParentheses(ParseNode* node, ExclusiveContext* cx) {
-        MOZ_ASSERT(isNameAnyParentheses(node),
-                   "must only call this function on known names");
-
-        return node->pn_atom == cx->names().eval;
+    bool isEvalAnyParentheses(ParseNode* node, ExclusiveContext* cx) {
+        return node->isKind(PNK_NAME) && node->pn_atom == cx->names().eval;
     }
 
     const char* nameIsArgumentsEvalAnyParentheses(ParseNode* node, ExclusiveContext* cx) {
         MOZ_ASSERT(isNameAnyParentheses(node),
                    "must only call this function on known names");
 
-        if (nameIsEvalAnyParentheses(node, cx))
+        if (isEvalAnyParentheses(node, cx))
             return js_eval_str;
         if (node->pn_atom == cx->names().arguments)
             return js_arguments_str;
         return nullptr;
     }
 
-    bool nameIsUnparenthesizedAsync(ParseNode* node, ExclusiveContext* cx) {
-        MOZ_ASSERT(isNameAnyParentheses(node),
-                   "must only call this function on known names");
-
-        return node->pn_atom == cx->names().async;
+    bool isAsyncKeyword(ParseNode* node, ExclusiveContext* cx) {
+        return node->isKind(PNK_NAME) &&
+               node->pn_pos.begin + strlen("async") == node->pn_pos.end &&
+               node->pn_atom == cx->names().async;
     }
 
     bool isCall(ParseNode* pn) {
diff --git a/js/src/frontend/Parser.cpp b/js/src/frontend/Parser.cpp
index 3b7a0e612..7d923420a 100644
--- a/js/src/frontend/Parser.cpp
+++ b/js/src/frontend/Parser.cpp
@@ -5147,7 +5147,10 @@ Parser<FullParseHandler>::exportDeclaration()
                 return null();
             break;
           default: {
-            if (tt == TOK_NAME && tokenStream.currentName() == context->names().async) {
+            if (tt == TOK_NAME &&
+                tokenStream.currentName() == context->names().async &&
+                !tokenStream.currentToken().nameContainsEscape())
+            {
                 TokenKind nextSameLine = TOK_EOF;
                 if (!tokenStream.peekTokenSameLine(&nextSameLine))
                     return null();
@@ -7045,21 +7048,23 @@ Parser<ParseHandler>::statementListItem(YieldHandling yieldHandling,
         if (!tokenStream.peekToken(&next))
             return null();
 
-        if (!tokenStream.currentToken().nameContainsEscape() &&
-            tokenStream.currentName() == context->names().let &&
-            nextTokenContinuesLetDeclaration(next, yieldHandling))
-        {
-            return lexicalDeclaration(yieldHandling, /* isConst = */ false);
-        }
+        if (!tokenStream.currentToken().nameContainsEscape()) {
+            if (tokenStream.currentName() == context->names().let &&
+                nextTokenContinuesLetDeclaration(next, yieldHandling))
+            {
+                return lexicalDeclaration(yieldHandling, /* isConst = */ false);
+            }
 
-        if (tokenStream.currentName() == context->names().async) {
-            TokenKind nextSameLine = TOK_EOF;
-            if (!tokenStream.peekTokenSameLine(&nextSameLine))
-                return null();
-            if (nextSameLine == TOK_FUNCTION) {
-                uint32_t preludeStart = pos().begin;
-                tokenStream.consumeKnownToken(TOK_FUNCTION);
-                return functionStmt(preludeStart, yieldHandling, NameRequired, AsyncFunction);
+            if (tokenStream.currentName() == context->names().async) {
+                TokenKind nextSameLine = TOK_EOF;
+                if (!tokenStream.peekTokenSameLine(&nextSameLine)) {
+                    return null();
+                }
+                if (nextSameLine == TOK_FUNCTION) {
+                    uint32_t preludeStart = pos().begin;
+                    tokenStream.consumeKnownToken(TOK_FUNCTION);
+                    return functionStmt(preludeStart, yieldHandling, NameRequired, AsyncFunction);
+                }
             }
         }
 
@@ -7516,7 +7521,10 @@ Parser<ParseHandler>::assignExpr(InHandling inHandling, YieldHandling yieldHandl
         return yieldExpression(inHandling);
 
     bool maybeAsyncArrow = false;
-    if (tt == TOK_NAME && tokenStream.currentName() == context->names().async) {
+    if (tt == TOK_NAME &&
+        tokenStream.currentName() == context->names().async &&
+        !tokenStream.currentToken().nameContainsEscape())
+    {
         TokenKind nextSameLine = TOK_EOF;
         if (!tokenStream.peekTokenSameLine(&nextSameLine))
             return null();
@@ -7537,6 +7545,7 @@ Parser<ParseHandler>::assignExpr(InHandling inHandling, YieldHandling yieldHandl
     if (maybeAsyncArrow) {
         tokenStream.consumeKnownToken(TOK_NAME, TokenStream::Operand);
         MOZ_ASSERT(tokenStream.currentName() == context->names().async);
+        MOZ_ASSERT(!tokenStream.currentToken().nameContainsEscape());
 
         TokenKind tt;
         if (!tokenStream.getToken(&tt))
@@ -7613,7 +7622,9 @@ Parser<ParseHandler>::assignExpr(InHandling inHandling, YieldHandling yieldHandl
         if (next == TOK_NAME) {
             tokenStream.consumeKnownToken(next, TokenStream::Operand);
 
-            if (tokenStream.currentName() == context->names().async) {
+            if (tokenStream.currentName() == context->names().async &&
+                !tokenStream.currentToken().nameContainsEscape())
+            {
                 TokenKind nextSameLine = TOK_EOF;
                 if (!tokenStream.peekTokenSameLine(&nextSameLine))
                     return null();
@@ -8448,8 +8459,27 @@ Parser<ParseHandler>::memberExpr(YieldHandling yieldHandling, TripledotHandling
 
                 JSOp op = JSOP_CALL;
                 bool maybeAsyncArrow = false;
-                if (tt == TOK_LP && handler.isNameAnyParentheses(lhs)) {
-                    if (handler.nameIsEvalAnyParentheses(lhs, context)) {
+                if (PropertyName* prop = handler.maybeDottedProperty(lhs)) {
+                    // Use the JSOP_FUN{APPLY,CALL} optimizations given the
+                    // right syntax.
+                    if (prop == context->names().apply) {
+                        op = JSOP_FUNAPPLY;
+                        if (pc->isFunctionBox()) {
+                            pc->functionBox()->usesApply = true;
+                        }
+                    } else if (prop == context->names().call) {
+                        op = JSOP_FUNCALL;
+                    }
+                } else if (tt == TOK_LP) {
+                    if (handler.isAsyncKeyword(lhs, context)) {
+                        // |async (| can be the start of an async arrow
+                        // function, so we need to defer reporting possible
+                        // errors from destructuring syntax. To give better
+                        // error messages, we only allow the AsyncArrowHead
+                        // part of the CoverCallExpressionAndAsyncArrowHead
+                        // syntax when the initial name is "async".
+                        maybeAsyncArrow = true;
+                    } else if (handler.isEvalAnyParentheses(lhs, context)) {
                         // Select the right EVAL op and flag pc as having a
                         // direct eval.
                         op = pc->sc()->strict() ? JSOP_STRICTEVAL : JSOP_EVAL;
@@ -8466,24 +8496,6 @@ Parser<ParseHandler>::memberExpr(YieldHandling yieldHandling, TripledotHandling
                         // it. (If we're not in a method, that's fine, so
                         // ignore the return value.)
                         checkAndMarkSuperScope();
-                    } else if (handler.nameIsUnparenthesizedAsync(lhs, context)) {
-                        // |async (| can be the start of an async arrow
-                        // function, so we need to defer reporting possible
-                        // errors from destructuring syntax. To give better
-                        // error messages, we only allow the AsyncArrowHead
-                        // part of the CoverCallExpressionAndAsyncArrowHead
-                        // syntax when the initial name is "async".
-                        maybeAsyncArrow = true;
-                    }
-                } else if (PropertyName* prop = handler.maybeDottedProperty(lhs)) {
-                    // Use the JSOP_FUN{APPLY,CALL} optimizations given the
-                    // right syntax.
-                    if (prop == context->names().apply) {
-                        op = JSOP_FUNAPPLY;
-                        if (pc->isFunctionBox())
-                            pc->functionBox()->usesApply = true;
-                    } else if (prop == context->names().call) {
-                        op = JSOP_FUNCALL;
                     }
                 }
 
@@ -8816,7 +8828,10 @@ Parser<ParseHandler>::propertyName(YieldHandling yieldHandling, Node propList,
             return null();
     }
 
-    if (ltok == TOK_NAME && tokenStream.currentName() == context->names().async) {
+    if (ltok == TOK_NAME &&
+        tokenStream.currentName() == context->names().async &&
+        !tokenStream.currentToken().nameContainsEscape())
+    {
         // AsyncMethod[Yield, Await]:
         //   async [no LineTerminator here] PropertyName[?Yield, ?Await] ...
         //
@@ -9404,7 +9419,9 @@ Parser<ParseHandler>::primaryExpr(YieldHandling yieldHandling, TripledotHandling
 
       case TOK_YIELD:
       case TOK_NAME: {
-        if (tokenStream.currentName() == context->names().async) {
+        if (tokenStream.currentName() == context->names().async &&
+            !tokenStream.currentToken().nameContainsEscape())
+        {
             TokenKind nextSameLine = TOK_EOF;
             if (!tokenStream.peekTokenSameLine(&nextSameLine))
                 return null();
diff --git a/js/src/frontend/SyntaxParseHandler.h b/js/src/frontend/SyntaxParseHandler.h
index 00ea9d35d..9dc3c1072 100644
--- a/js/src/frontend/SyntaxParseHandler.h
+++ b/js/src/frontend/SyntaxParseHandler.h
@@ -9,6 +9,8 @@
 
 #include "mozilla/Attributes.h"
 
+#include <string.h>
+
 #include "frontend/ParseNode.h"
 #include "frontend/TokenStream.h"
 
@@ -94,10 +96,13 @@ class SyntaxParseHandler
 
         // Nodes representing unparenthesized names.
         NodeUnparenthesizedArgumentsName,
-        NodeUnparenthesizedAsyncName,
         NodeUnparenthesizedEvalName,
         NodeUnparenthesizedName,
 
+        // Node representing the "async" name, which may actually be a
+        // contextual keyword.
+        NodePotentialAsyncKeyword,
+
         // Valuable for recognizing potential destructuring patterns.
         NodeUnparenthesizedArray,
         NodeUnparenthesizedObject,
@@ -183,8 +188,8 @@ class SyntaxParseHandler
         lastAtom = name;
         if (name == cx->names().arguments)
             return NodeUnparenthesizedArgumentsName;
-        if (name == cx->names().async)
-            return NodeUnparenthesizedAsyncName;
+        if (pos.begin + strlen("async") == pos.end && name == cx->names().async)
+            return NodePotentialAsyncKeyword;
         if (name == cx->names().eval)
             return NodeUnparenthesizedEvalName;
         return NodeUnparenthesizedName;
@@ -497,7 +502,7 @@ class SyntaxParseHandler
             return NodeParenthesizedArgumentsName;
         if (node == NodeUnparenthesizedEvalName)
             return NodeParenthesizedEvalName;
-        if (node == NodeUnparenthesizedName || node == NodeUnparenthesizedAsyncName)
+        if (node == NodeUnparenthesizedName || node == NodePotentialAsyncKeyword)
             return NodeParenthesizedName;
 
         if (node == NodeUnparenthesizedArray)
@@ -528,9 +533,9 @@ class SyntaxParseHandler
 
     bool isUnparenthesizedName(Node node) {
         return node == NodeUnparenthesizedArgumentsName ||
-               node == NodeUnparenthesizedAsyncName ||
                node == NodeUnparenthesizedEvalName ||
-               node == NodeUnparenthesizedName;
+               node == NodeUnparenthesizedName ||
+               node == NodePotentialAsyncKeyword;
     }
 
     bool isNameAnyParentheses(Node node) {
@@ -541,9 +546,7 @@ class SyntaxParseHandler
                node == NodeParenthesizedName;
     }
 
-    bool nameIsEvalAnyParentheses(Node node, ExclusiveContext* cx) {
-        MOZ_ASSERT(isNameAnyParentheses(node),
-                   "must only call this function on known names");
+    bool isEvalAnyParentheses(Node node, ExclusiveContext* cx) {
         return node == NodeUnparenthesizedEvalName || node == NodeParenthesizedEvalName;
     }
 
@@ -551,17 +554,15 @@ class SyntaxParseHandler
         MOZ_ASSERT(isNameAnyParentheses(node),
                    "must only call this method on known names");
 
-        if (nameIsEvalAnyParentheses(node, cx))
+        if (isEvalAnyParentheses(node, cx))
             return js_eval_str;
         if (node == NodeUnparenthesizedArgumentsName || node == NodeParenthesizedArgumentsName)
             return js_arguments_str;
         return nullptr;
     }
 
-    bool nameIsUnparenthesizedAsync(Node node, ExclusiveContext* cx) {
-        MOZ_ASSERT(isNameAnyParentheses(node),
-                   "must only call this function on known names");
-        return node == NodeUnparenthesizedAsyncName;
+    bool isAsyncKeyword(Node node, ExclusiveContext* cx) {
+        return node == NodePotentialAsyncKeyword;
     }
 
     PropertyName* maybeDottedProperty(Node node) {