[strong] no sloppy equality

R=marja@chromium.org
BUG=

Review URL: https://codereview.chromium.org/917703003

Cr-Commit-Position: refs/heads/master@{#26619}

src/bootstrapper.cc

@@ -1366,7 +1366,14 @@ bool Genesis::CompileExperimentalBuiltin(Isolate* isolate, int index) {
       isolate, source_code,
       factory->NewStringFromAscii(ExperimentalNatives::GetScriptSource(index)),
       false);
-  return CompileNative(isolate, name, source_code);
+
+  // TODO(rossberg): The natives do not yet obey strong mode rules
+  // (for example, some macros use '==').
+  bool use_strong = FLAG_use_strong;
+  FLAG_use_strong = false;
+  bool result = CompileNative(isolate, name, source_code);
+  FLAG_use_strong = use_strong;
+  return result;
 }
 
 

src/d8.cc

@@ -840,6 +840,10 @@ void Shell::AddHistogramSample(void* histogram, int sample) {
 
 void Shell::InstallUtilityScript(Isolate* isolate) {
   HandleScope scope(isolate);
+  // TODO(rossberg): Utility scripts do not yet obey strong mode rules.
+  bool use_strong = i::FLAG_use_strong;
+  i::FLAG_use_strong = false;
+
   // If we use the utility context, we have to set the security tokens so that
   // utility, evaluation and debug context can all access each other.
   v8::Local<v8::Context> utility_context =
@@ -889,6 +893,8 @@ void Shell::InstallUtilityScript(Isolate* isolate) {
 
   // Start the in-process debugger if requested.
   if (i::FLAG_debugger) v8::Debug::SetDebugEventListener(HandleDebugEvent);
+
+  i::FLAG_use_strong = use_strong;
 }
 #endif  // !V8_SHARED
 

src/messages.js

@@ -161,6 +161,7 @@ var kMessages = {
   strict_cannot_assign:          ["Cannot assign to read only '", "%0", "' in strict mode"],
   strict_poison_pill:            ["'caller', 'callee', and 'arguments' properties may not be accessed on strict mode functions or the arguments objects for calls to them"],
   strict_caller:                 ["Illegal access to a strict mode caller function."],
+  strong_equal:                  ["Please don't use '==' or '!=' in strong mode, use '===' or '!==' instead"],
   malformed_arrow_function_parameter_list: ["Malformed arrow function parameter list"],
   generator_poison_pill:         ["'caller' and 'arguments' properties may not be accessed on generator functions."],
   cant_prevent_ext_external_array_elements: ["Cannot prevent extension of an object with external array elements"],

src/preparser.h

@@ -2440,6 +2440,7 @@ ParserBase<Traits>::ParseBinaryExpression(int prec, bool accept_IN, bool* ok) {
     // prec1 >= 4
     while (Precedence(peek(), accept_IN) == prec1) {
       Token::Value op = Next();
+      Scanner::Location op_location = scanner()->location();
       int pos = position();
       ExpressionT y = ParseBinaryExpression(prec1 + 1, accept_IN, CHECK_OK);
 
@@ -2459,6 +2460,11 @@ ParserBase<Traits>::ParseBinaryExpression(int prec, bool accept_IN, bool* ok) {
           case Token::NE_STRICT: cmp = Token::EQ_STRICT; break;
           default: break;
         }
+        if (cmp == Token::EQ && is_strong(language_mode())) {
+          ReportMessageAt(op_location, "strong_equal");
+          *ok = false;
+          return this->EmptyExpression();
+        }
         x = factory()->NewCompareOperation(cmp, x, y, pos);
         if (cmp != op) {
           // The comparison was negated - add a NOT.

src/scopes.cc

@@ -161,7 +161,7 @@ void Scope::SetDefaults(ScopeType scope_type,
   scope_uses_this_ = false;
   asm_module_ = false;
   asm_function_ = outer_scope != NULL && outer_scope->asm_module_;
-  // Inherit the strict mode from the parent scope.
+  // Inherit the language mode from the parent scope.
   language_mode_ = outer_scope != NULL ? outer_scope->language_mode_ : SLOPPY;
   outer_scope_calls_sloppy_eval_ = false;
   inner_scope_calls_eval_ = false;
@@ -892,7 +892,9 @@ void Scope::Print(int n) {
   if (HasTrivialOuterContext()) {
     Indent(n1, "// scope has trivial outer context\n");
   }
-  if (is_strict(language_mode())) {
+  if (is_strong(language_mode())) {
+    Indent(n1, "// strong mode scope\n");
+  } else if (is_strict(language_mode())) {
     Indent(n1, "// strict mode scope\n");
   }
   if (scope_inside_with_) Indent(n1, "// scope inside 'with'\n");

test/mjsunit/strong/equality.js

+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --strong-mode
+
+(function NoSloppyEquality() {
+  assertThrows("'use strong'; 0 == 0", SyntaxError);
+  assertThrows("'use strong'; 0 != 0", SyntaxError);
+  assertThrows("function f() { 'use strong'; 0 == 0 }", SyntaxError);
+  assertThrows("function f() { 'use strong'; 0 != 0 }", SyntaxError);
+  assertTrue(eval("function f() { 'use strong' } 0 == 0"));
+  assertTrue(eval("function f() { 'use strong' } 0 != 1"));
+})();