Reland 2 ScriptContext CLs

Changing script context handling from bytecode based to metadata on the
function. This fixes the debugger to explicitly check the code rather
than implicitly relying on a NewScriptContext bytecode causing side
effects.

Bug: chromium:1043151
Tbr: ulan@chromium.org
Change-Id: I38c5c04d7c76155e0a055ae6efd57f25986bdb7d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2013117Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65920}

src/builtins/builtins-error.cc

@@ -96,11 +96,9 @@ Object MakeGenericError(Isolate* isolate, BuiltinArguments args,
 
   DCHECK(template_index->IsSmi());
 
-  RETURN_RESULT_OR_FAILURE(
-      isolate, ErrorUtils::MakeGenericError(
-                   isolate, constructor,
-                   MessageTemplateFromInt(Smi::ToInt(*template_index)), arg0,
-                   arg1, arg2, SKIP_NONE));
+  return *ErrorUtils::MakeGenericError(
+      isolate, constructor, MessageTemplateFromInt(Smi::ToInt(*template_index)),
+      arg0, arg1, arg2, SKIP_NONE);
 }
 
 }  // namespace
@@ -130,10 +128,9 @@ BUILTIN(MakeURIError) {
   Handle<JSFunction> constructor = isolate->uri_error_function();
   Handle<Object> undefined = isolate->factory()->undefined_value();
   MessageTemplate template_index = MessageTemplate::kURIMalformed;
-  RETURN_RESULT_OR_FAILURE(
-      isolate,
-      ErrorUtils::MakeGenericError(isolate, constructor, template_index,
-                                   undefined, undefined, undefined, SKIP_NONE));
+  return *ErrorUtils::MakeGenericError(isolate, constructor, template_index,
+                                       undefined, undefined, undefined,
+                                       SKIP_NONE);
 }
 
 }  // namespace internal

src/debug/debug-evaluate.cc

@@ -864,6 +864,8 @@ DebugInfo::SideEffectState DebugEvaluate::FunctionGetSideEffectState(
            info->DebugName().ToCString().get());
   }
 
+  if (info->needs_script_context()) return DebugInfo::kHasSideEffects;
+
   DCHECK(info->is_compiled());
   if (info->HasBytecodeArray()) {
     // Check bytecodes against whitelist.

src/execution/execution.cc

@@ -157,6 +157,84 @@ Handle<Code> JSEntry(Isolate* isolate, Execution::Target execution_target,
   UNREACHABLE();
 }
 
+MaybeHandle<Context> NewScriptContext(Isolate* isolate,
+                                      Handle<JSFunction> function) {
+  SaveAndSwitchContext save(isolate, function->context());
+  SharedFunctionInfo sfi = function->shared();
+  Handle<Script> script(Script::cast(sfi.script()), isolate);
+  Handle<ScopeInfo> scope_info(sfi.scope_info(), isolate);
+  Handle<NativeContext> native_context(NativeContext::cast(function->context()),
+                                       isolate);
+  Handle<JSGlobalObject> global_object(native_context->global_object(),
+                                       isolate);
+  Handle<ScriptContextTable> script_context(
+      native_context->script_context_table(), isolate);
+
+  // Find name clashes.
+  for (int var = 0; var < scope_info->ContextLocalCount(); var++) {
+    Handle<String> name(scope_info->ContextLocalName(var), isolate);
+    VariableMode mode = scope_info->ContextLocalMode(var);
+    ScriptContextTable::LookupResult lookup;
+    if (ScriptContextTable::Lookup(isolate, *script_context, *name, &lookup)) {
+      if (IsLexicalVariableMode(mode) || IsLexicalVariableMode(lookup.mode)) {
+        Handle<Context> context = ScriptContextTable::GetContext(
+            isolate, script_context, lookup.context_index);
+        // If we are trying to re-declare a REPL-mode let as a let, allow it.
+        if (!(mode == VariableMode::kLet && lookup.mode == VariableMode::kLet &&
+              scope_info->IsReplModeScope() &&
+              context->scope_info().IsReplModeScope())) {
+          // ES#sec-globaldeclarationinstantiation 5.b:
+          // If envRec.HasLexicalDeclaration(name) is true, throw a SyntaxError
+          // exception.
+          MessageLocation location(script, 0, 1);
+          isolate->ThrowAt(isolate->factory()->NewSyntaxError(
+                               MessageTemplate::kVarRedeclaration, name),
+                           &location);
+          return MaybeHandle<Context>();
+        }
+      }
+    }
+
+    if (IsLexicalVariableMode(mode)) {
+      LookupIterator it(isolate, global_object, name, global_object,
+                        LookupIterator::OWN_SKIP_INTERCEPTOR);
+      Maybe<PropertyAttributes> maybe = JSReceiver::GetPropertyAttributes(&it);
+      // Can't fail since the we looking up own properties on the global object
+      // skipping interceptors.
+      CHECK(!maybe.IsNothing());
+      if ((maybe.FromJust() & DONT_DELETE) != 0) {
+        // ES#sec-globaldeclarationinstantiation 5.a:
+        // If envRec.HasVarDeclaration(name) is true, throw a SyntaxError
+        // exception.
+        // ES#sec-globaldeclarationinstantiation 5.d:
+        // If hasRestrictedGlobal is true, throw a SyntaxError exception.
+        MessageLocation location(script, 0, 1);
+        isolate->ThrowAt(isolate->factory()->NewSyntaxError(
+                             MessageTemplate::kVarRedeclaration, name),
+                         &location);
+        return MaybeHandle<Context>();
+      }
+
+      JSGlobalObject::InvalidatePropertyCell(global_object, name);
+    }
+  }
+
+  Handle<Context> result =
+      isolate->factory()->NewScriptContext(native_context, scope_info);
+
+  int header = scope_info->ContextHeaderLength();
+  for (int var = 0; var < scope_info->ContextLocalCount(); var++) {
+    if (scope_info->ContextLocalInitFlag(var) == kNeedsInitialization) {
+      result->set(header + var, ReadOnlyRoots(isolate).the_hole_value());
+    }
+  }
+
+  Handle<ScriptContextTable> new_script_context_table =
+      ScriptContextTable::Extend(script_context, result);
+  native_context->set_script_context_table(*new_script_context_table);
+  return result;
+}
+
 V8_WARN_UNUSED_RESULT MaybeHandle<Object> Invoke(Isolate* isolate,
                                                  const InvokeParams& params) {
   RuntimeCallTimerScope timer(isolate, RuntimeCallCounterId::kInvoke);
@@ -206,6 +284,22 @@ V8_WARN_UNUSED_RESULT MaybeHandle<Object> Invoke(Isolate* isolate,
       }
       return value;
     }
+
+    // Set up a ScriptContext when running scripts that need it.
+    if (function->shared().needs_script_context()) {
+      Handle<Context> context;
+      if (!NewScriptContext(isolate, function).ToHandle(&context)) {
+        if (params.message_handling == Execution::MessageHandling::kReport) {
+          isolate->ReportPendingMessages();
+        }
+        return MaybeHandle<Object>();
+      }
+
+      // We mutate the context if we allocate a script context. This is
+      // guaranteed to only happen once in a native context since scripts will
+      // always produce name clashes with themselves.
+      function->set_context(*context);
+    }
   }
 
   // Entering JavaScript.

src/execution/isolate.cc

@@ -1342,6 +1342,30 @@ Object Isolate::StackOverflow() {
   return ReadOnlyRoots(heap()).exception();
 }
 
+void Isolate::ThrowAt(Handle<JSObject> exception, MessageLocation* location) {
+  Handle<Name> key_start_pos = factory()->error_start_pos_symbol();
+  Object::SetProperty(this, exception, key_start_pos,
+                      handle(Smi::FromInt(location->start_pos()), this),
+                      StoreOrigin::kMaybeKeyed,
+                      Just(ShouldThrow::kThrowOnError))
+      .Check();
+
+  Handle<Name> key_end_pos = factory()->error_end_pos_symbol();
+  Object::SetProperty(this, exception, key_end_pos,
+                      handle(Smi::FromInt(location->end_pos()), this),
+                      StoreOrigin::kMaybeKeyed,
+                      Just(ShouldThrow::kThrowOnError))
+      .Check();
+
+  Handle<Name> key_script = factory()->error_script_symbol();
+  Object::SetProperty(this, exception, key_script, location->script(),
+                      StoreOrigin::kMaybeKeyed,
+                      Just(ShouldThrow::kThrowOnError))
+      .Check();
+
+  Throw(*exception, location);
+}
+
 Object Isolate::TerminateExecution() {
   return Throw(ReadOnlyRoots(this).termination_exception(), nullptr);
 }

src/execution/isolate.h

@@ -772,6 +772,8 @@ class Isolate final : private HiddenFactory {
     return MaybeHandle<T>();
   }
 
+  void ThrowAt(Handle<JSObject> exception, MessageLocation* location);
+
   void set_console_delegate(debug::ConsoleDelegate* delegate) {
     console_delegate_ = delegate;
   }

src/execution/messages.cc

@@ -990,7 +990,7 @@ MaybeHandle<String> MessageFormatter::Format(Isolate* isolate,
   return builder.Finish();
 }
 
-MaybeHandle<Object> ErrorUtils::Construct(
+MaybeHandle<JSObject> ErrorUtils::Construct(
     Isolate* isolate, Handle<JSFunction> target, Handle<Object> new_target,
     Handle<Object> message, FrameSkipMode mode, Handle<Object> caller,
     StackTraceCollection stack_trace_collection) {
@@ -1007,7 +1007,7 @@ MaybeHandle<Object> ErrorUtils::Construct(
   ASSIGN_RETURN_ON_EXCEPTION(
       isolate, err,
       JSObject::New(target, new_target_recv, Handle<AllocationSite>::null()),
-      Object);
+      JSObject);
 
   // 3. If message is not undefined, then
   //  a. Let msg be ? ToString(message).
@@ -1019,23 +1019,23 @@ MaybeHandle<Object> ErrorUtils::Construct(
   if (!message->IsUndefined(isolate)) {
     Handle<String> msg_string;
     ASSIGN_RETURN_ON_EXCEPTION(isolate, msg_string,
-                               Object::ToString(isolate, message), Object);
+                               Object::ToString(isolate, message), JSObject);
     RETURN_ON_EXCEPTION(
         isolate,
         JSObject::SetOwnPropertyIgnoreAttributes(
             err, isolate->factory()->message_string(), msg_string, DONT_ENUM),
-        Object);
+        JSObject);
   }
 
   switch (stack_trace_collection) {
     case StackTraceCollection::kDetailed:
       RETURN_ON_EXCEPTION(
-          isolate, isolate->CaptureAndSetDetailedStackTrace(err), Object);
+          isolate, isolate->CaptureAndSetDetailedStackTrace(err), JSObject);
       V8_FALLTHROUGH;
     case StackTraceCollection::kSimple:
       RETURN_ON_EXCEPTION(
           isolate, isolate->CaptureAndSetSimpleStackTrace(err, mode, caller),
-          Object);
+          JSObject);
       break;
     case StackTraceCollection::kNone:
       break;
@@ -1144,7 +1144,7 @@ Handle<String> DoFormatMessage(Isolate* isolate, MessageTemplate index,
 }  // namespace
 
 // static
-MaybeHandle<Object> ErrorUtils::MakeGenericError(
+Handle<JSObject> ErrorUtils::MakeGenericError(
     Isolate* isolate, Handle<JSFunction> constructor, MessageTemplate index,
     Handle<Object> arg0, Handle<Object> arg1, Handle<Object> arg2,
     FrameSkipMode mode) {
@@ -1167,8 +1167,11 @@ MaybeHandle<Object> ErrorUtils::MakeGenericError(
   DCHECK(mode != SKIP_UNTIL_SEEN);
 
   Handle<Object> no_caller;
+  // The call below can't fail because constructor is a builtin.
+  DCHECK(constructor->shared().HasBuiltinId());
   return ErrorUtils::Construct(isolate, constructor, constructor, msg, mode,
-                               no_caller, StackTraceCollection::kDetailed);
+                               no_caller, StackTraceCollection::kDetailed)
+      .ToHandleChecked();
 }
 
 namespace {

src/execution/messages.h

@@ -269,14 +269,14 @@ class ErrorUtils : public AllStatic {
   // |kNone| is useful when you don't need the stack information at all, for
   // example when creating a deserialized error.
   enum class StackTraceCollection { kDetailed, kSimple, kNone };
-  static MaybeHandle<Object> Construct(
+  static MaybeHandle<JSObject> Construct(
       Isolate* isolate, Handle<JSFunction> target, Handle<Object> new_target,
       Handle<Object> message, FrameSkipMode mode, Handle<Object> caller,
       StackTraceCollection stack_trace_collection);
 
   static MaybeHandle<String> ToString(Isolate* isolate, Handle<Object> recv);
 
-  static MaybeHandle<Object> MakeGenericError(
+  static Handle<JSObject> MakeGenericError(
       Isolate* isolate, Handle<JSFunction> constructor, MessageTemplate index,
       Handle<Object> arg0, Handle<Object> arg1, Handle<Object> arg2,
       FrameSkipMode mode);

src/heap/factory.cc

@@ -1267,9 +1267,10 @@ Handle<Context> Factory::NewScriptContext(Handle<NativeContext> outer,
                                           Handle<ScopeInfo> scope_info) {
   DCHECK_EQ(scope_info->scope_type(), SCRIPT_SCOPE);
   int variadic_part_length = scope_info->ContextLength();
-  Handle<Context> context = NewContext(
-      isolate()->script_context_map(), Context::SizeFor(variadic_part_length),
-      variadic_part_length, AllocationType::kOld);
+  Handle<Context> context =
+      NewContext(handle(outer->script_context_map(), isolate()),
+                 Context::SizeFor(variadic_part_length), variadic_part_length,
+                 AllocationType::kOld);
   context->set_scope_info(*scope_info);
   context->set_previous(*outer);
   DCHECK(context->IsScriptContext());
@@ -2084,51 +2085,30 @@ Handle<FreshlyAllocatedBigInt> Factory::NewBigInt(int length,
   return handle(bigint, isolate());
 }
 
-Handle<Object> Factory::NewError(Handle<JSFunction> constructor,
+Handle<JSObject> Factory::NewError(Handle<JSFunction> constructor,
                                    MessageTemplate template_index,
                                    Handle<Object> arg0, Handle<Object> arg1,
                                    Handle<Object> arg2) {
   HandleScope scope(isolate());
-  if (isolate()->bootstrapper()->IsActive()) {
-    // During bootstrapping we cannot construct error objects.
-    return scope.CloseAndEscape(NewStringFromAsciiChecked(
-        MessageFormatter::TemplateString(template_index)));
-  }
 
   if (arg0.is_null()) arg0 = undefined_value();
   if (arg1.is_null()) arg1 = undefined_value();
   if (arg2.is_null()) arg2 = undefined_value();
 
-  Handle<Object> result;
-  if (!ErrorUtils::MakeGenericError(isolate(), constructor, template_index,
-                                    arg0, arg1, arg2, SKIP_NONE)
-           .ToHandle(&result)) {
-    // If an exception is thrown while
-    // running the factory method, use the exception as the result.
-    DCHECK(isolate()->has_pending_exception());
-    result = handle(isolate()->pending_exception(), isolate());
-    isolate()->clear_pending_exception();
-  }
-
-  return scope.CloseAndEscape(result);
+  return scope.CloseAndEscape(ErrorUtils::MakeGenericError(
+      isolate(), constructor, template_index, arg0, arg1, arg2, SKIP_NONE));
 }
 
-Handle<Object> Factory::NewError(Handle<JSFunction> constructor,
+Handle<JSObject> Factory::NewError(Handle<JSFunction> constructor,
                                    Handle<String> message) {
   // Construct a new error object. If an exception is thrown, use the exception
   // as the result.
 
   Handle<Object> no_caller;
-  MaybeHandle<Object> maybe_error = ErrorUtils::Construct(
-      isolate(), constructor, constructor, message, SKIP_NONE, no_caller,
-      ErrorUtils::StackTraceCollection::kDetailed);
-  if (maybe_error.is_null()) {
-    DCHECK(isolate()->has_pending_exception());
-    maybe_error = handle(isolate()->pending_exception(), isolate());
-    isolate()->clear_pending_exception();
-  }
-
-  return maybe_error.ToHandleChecked();
+  return ErrorUtils::Construct(isolate(), constructor, constructor, message,
+                               SKIP_NONE, no_caller,
+                               ErrorUtils::StackTraceCollection::kDetailed)
+      .ToHandleChecked();
 }
 
 Handle<Object> Factory::NewInvalidStringLengthError() {
@@ -2143,9 +2123,9 @@ Handle<Object> Factory::NewInvalidStringLengthError() {
 }
 
 #define DEFINE_ERROR(NAME, name)                                              \
-  Handle<Object> Factory::New##NAME(MessageTemplate template_index,           \
-                                    Handle<Object> arg0, Handle<Object> arg1, \
-                                    Handle<Object> arg2) {                    \
+  Handle<JSObject> Factory::New##NAME(                                        \
+      MessageTemplate template_index, Handle<Object> arg0,                    \
+      Handle<Object> arg1, Handle<Object> arg2) {                             \
     return NewError(isolate()->name##_function(), template_index, arg0, arg1, \
                     arg2);                                                    \
   }

src/heap/factory.h

@@ -770,21 +770,21 @@ class V8_EXPORT_PRIVATE Factory : public FactoryBase<Factory> {
   Handle<BytecodeArray> CopyBytecodeArray(Handle<BytecodeArray>);
 
   // Interface for creating error objects.
-  Handle<Object> NewError(Handle<JSFunction> constructor,
+  Handle<JSObject> NewError(Handle<JSFunction> constructor,
                             Handle<String> message);
 
   Handle<Object> NewInvalidStringLengthError();
 
   inline Handle<Object> NewURIError();
 
-  Handle<Object> NewError(Handle<JSFunction> constructor,
+  Handle<JSObject> NewError(Handle<JSFunction> constructor,
                             MessageTemplate template_index,
                             Handle<Object> arg0 = Handle<Object>(),
                             Handle<Object> arg1 = Handle<Object>(),
                             Handle<Object> arg2 = Handle<Object>());
 
 #define DECLARE_ERROR(NAME)                                          \
-  Handle<Object> New##NAME(MessageTemplate template_index,         \
+  Handle<JSObject> New##NAME(MessageTemplate template_index,         \
                              Handle<Object> arg0 = Handle<Object>(), \
                              Handle<Object> arg1 = Handle<Object>(), \
                              Handle<Object> arg2 = Handle<Object>());

src/interpreter/bytecode-generator.cc

@@ -1166,7 +1166,7 @@ void BytecodeGenerator::GenerateBytecode(uintptr_t stack_limit) {
     BuildGeneratorPrologue();
   }
 
-  if (closure_scope()->NeedsContext()) {
+  if (closure_scope()->NeedsContext() && !closure_scope()->is_script_scope()) {
     // Push a new inner context scope for the function.
     BuildNewLocalActivationContext();
     ContextScope local_function_context(this, closure_scope());
@@ -1320,8 +1320,7 @@ void BytecodeGenerator::VisitVariableDeclaration(VariableDeclaration* decl) {
 
   switch (variable->location()) {
     case VariableLocation::UNALLOCATED:
-      globals_builder()->record_global_declaration();
-      break;
+      UNREACHABLE();
     case VariableLocation::LOCAL:
       if (variable->binding_needs_init()) {
         Register destination(builder()->Local(variable->index()));
@@ -1376,9 +1375,7 @@ void BytecodeGenerator::VisitFunctionDeclaration(FunctionDeclaration* decl) {
 
   switch (variable->location()) {
     case VariableLocation::UNALLOCATED:
-      AddToEagerLiteralsIfEager(decl->fun());
-      globals_builder()->record_global_declaration();
-      break;
+      UNREACHABLE();
     case VariableLocation::PARAMETER:
     case VariableLocation::LOCAL: {
       VisitFunctionLiteral(decl->fun());
@@ -1435,9 +1432,26 @@ void BytecodeGenerator::VisitModuleNamespaceImports() {
 
 void BytecodeGenerator::VisitGlobalDeclarations(Declaration::List* decls) {
   RegisterAllocationScope register_scope(this);
-  VisitDeclarations(decls);
+  bool has_global_declaration = false;
+  for (Declaration* decl : *decls) {
+    Variable* var = decl->var();
+    DCHECK(var->is_used());
+    if (var->location() == VariableLocation::UNALLOCATED) {
+      // var or function.
+      has_global_declaration = true;
+      if (decl->IsFunctionDeclaration()) {
+        FunctionDeclaration* f = static_cast<FunctionDeclaration*>(decl);
+        AddToEagerLiteralsIfEager(f->fun());
+      }
+    } else {
+      // let or const. Handled in NewScriptContext.
+      DCHECK(decl->IsVariableDeclaration());
+      DCHECK(IsLexicalVariableMode(var->mode()));
+    }
+  }
 
-  if (!globals_builder()->has_global_declaration()) return;
+  if (!has_global_declaration) return;
+  globals_builder()->record_global_declaration();
   DCHECK(!globals_builder()->processed());
 
   globals_builder()->set_constant_pool_entry(
@@ -5982,13 +5996,7 @@ void BytecodeGenerator::BuildNewLocalActivationContext() {
   DCHECK_EQ(current_scope(), closure_scope());
 
   // Create the appropriate context.
-  if (scope->is_script_scope()) {
-    Register scope_reg = register_allocator()->NewRegister();
-    builder()
-        ->LoadLiteral(scope)
-        .StoreAccumulatorInRegister(scope_reg)
-        .CallRuntime(Runtime::kNewScriptContext, scope_reg);
-  } else if (scope->is_module_scope()) {
+  if (scope->is_module_scope()) {
     // We don't need to do anything for the outer script scope.
     DCHECK(scope->outer_scope()->is_script_scope());
 

src/objects/scope-info.cc

@@ -581,6 +581,10 @@ ScopeType ScopeInfo::scope_type() const {
   return ScopeTypeBits::decode(Flags());
 }
 
+bool ScopeInfo::is_script_scope() const {
+  return length() > 0 && scope_type() == SCRIPT_SCOPE;
+}
+
 bool ScopeInfo::SloppyEvalCanExtendVars() const {
   bool sloppy_eval_can_extend_vars =
       length() > 0 && SloppyEvalCanExtendVarsBit::decode(Flags());

src/objects/scope-info.h

@@ -196,6 +196,8 @@ class ScopeInfo : public FixedArray, public TorqueGeneratedScopeFlagsFields {
   // Return the outer ScopeInfo if present.
   ScopeInfo OuterScopeInfo() const;
 
+  bool is_script_scope() const;
+
   // Returns true if this ScopeInfo has a black list attached containing
   // stack allocated local variables.
   V8_EXPORT_PRIVATE bool HasLocalsBlackList() const;

src/objects/shared-function-info-inl.h

@@ -148,6 +148,16 @@ void SharedFunctionInfo::SetName(String name) {
   UpdateFunctionMapIndex();
 }
 
+bool SharedFunctionInfo::is_script() const {
+  return scope_info().is_script_scope() &&
+         Script::cast(script()).compilation_type() ==
+             Script::COMPILATION_TYPE_HOST;
+}
+
+bool SharedFunctionInfo::needs_script_context() const {
+  return is_script() && scope_info().ContextLocalCount() > 0;
+}
+
 AbstractCode SharedFunctionInfo::abstract_code() {
   if (HasBytecodeArray()) {
     return AbstractCode::cast(GetBytecodeArray());

src/objects/shared-function-info.h

@@ -223,6 +223,9 @@ class SharedFunctionInfo : public HeapObject,
   inline void set_raw_scope_info(ScopeInfo scope_info,
                                  WriteBarrierMode mode = UPDATE_WRITE_BARRIER);
 
+  inline bool is_script() const;
+  inline bool needs_script_context() const;
+
   // End position of this function in the script source.
   V8_EXPORT_PRIVATE int EndPosition() const;
 

src/parsing/pending-compilation-error-handler.cc

@@ -97,37 +97,9 @@ void PendingCompilationErrorHandler::ThrowPendingError(Isolate* isolate,
   isolate->debug()->OnCompileError(script);
 
   Factory* factory = isolate->factory();
-  Handle<Object> error =
+  Handle<JSObject> error =
       factory->NewSyntaxError(error_details_.message(), argument);
-
-  if (!error->IsJSObject()) {
-    isolate->Throw(*error, &location);
-    return;
-  }
-
-  Handle<JSObject> jserror = Handle<JSObject>::cast(error);
-
-  Handle<Name> key_start_pos = factory->error_start_pos_symbol();
-  Object::SetProperty(isolate, jserror, key_start_pos,
-                      handle(Smi::FromInt(location.start_pos()), isolate),
-                      StoreOrigin::kMaybeKeyed,
-                      Just(ShouldThrow::kThrowOnError))
-      .Check();
-
-  Handle<Name> key_end_pos = factory->error_end_pos_symbol();
-  Object::SetProperty(isolate, jserror, key_end_pos,
-                      handle(Smi::FromInt(location.end_pos()), isolate),
-                      StoreOrigin::kMaybeKeyed,
-                      Just(ShouldThrow::kThrowOnError))
-      .Check();
-
-  Handle<Name> key_script = factory->error_script_symbol();
-  Object::SetProperty(isolate, jserror, key_script, script,
-                      StoreOrigin::kMaybeKeyed,
-                      Just(ShouldThrow::kThrowOnError))
-      .Check();
-
-  isolate->Throw(*error, &location);
+  isolate->ThrowAt(error, &location);
 }
 
 Handle<String> PendingCompilationErrorHandler::FormatErrorMessageForTest(

src/runtime/runtime-scopes.cc

@@ -597,76 +597,6 @@ RUNTIME_FUNCTION(Runtime_NewClosure_Tenured) {
   return *function;
 }
 
-static Object FindNameClash(Isolate* isolate, Handle<ScopeInfo> scope_info,
-                            Handle<JSGlobalObject> global_object,
-                            Handle<ScriptContextTable> script_context) {
-  for (int var = 0; var < scope_info->ContextLocalCount(); var++) {
-    Handle<String> name(scope_info->ContextLocalName(var), isolate);
-    VariableMode mode = scope_info->ContextLocalMode(var);
-    ScriptContextTable::LookupResult lookup;
-    if (ScriptContextTable::Lookup(isolate, *script_context, *name, &lookup)) {
-      if (IsLexicalVariableMode(mode) || IsLexicalVariableMode(lookup.mode)) {
-        Handle<Context> context = ScriptContextTable::GetContext(
-            isolate, script_context, lookup.context_index);
-        // If we are trying to re-declare a REPL-mode let as a let, allow it.
-        if (!(mode == VariableMode::kLet && lookup.mode == VariableMode::kLet &&
-              scope_info->IsReplModeScope() &&
-              context->scope_info().IsReplModeScope())) {
-          // ES#sec-globaldeclarationinstantiation 5.b:
-          // If envRec.HasLexicalDeclaration(name) is true, throw a SyntaxError
-          // exception.
-          return ThrowRedeclarationError(isolate, name,
-                                         RedeclarationType::kSyntaxError);
-        }
-      }
-    }
-
-    if (IsLexicalVariableMode(mode)) {
-      LookupIterator it(isolate, global_object, name, global_object,
-                        LookupIterator::OWN_SKIP_INTERCEPTOR);
-      Maybe<PropertyAttributes> maybe = JSReceiver::GetPropertyAttributes(&it);
-      if (maybe.IsNothing()) return ReadOnlyRoots(isolate).exception();
-      if ((maybe.FromJust() & DONT_DELETE) != 0) {
-        // ES#sec-globaldeclarationinstantiation 5.a:
-        // If envRec.HasVarDeclaration(name) is true, throw a SyntaxError
-        // exception.
-        // ES#sec-globaldeclarationinstantiation 5.d:
-        // If hasRestrictedGlobal is true, throw a SyntaxError exception.
-        return ThrowRedeclarationError(isolate, name,
-                                       RedeclarationType::kSyntaxError);
-      }
-
-      JSGlobalObject::InvalidatePropertyCell(global_object, name);
-    }
-  }
-  return ReadOnlyRoots(isolate).undefined_value();
-}
-
-RUNTIME_FUNCTION(Runtime_NewScriptContext) {
-  HandleScope scope(isolate);
-  DCHECK_EQ(1, args.length());
-
-  CONVERT_ARG_HANDLE_CHECKED(ScopeInfo, scope_info, 0);
-  Handle<NativeContext> native_context(NativeContext::cast(isolate->context()),
-                                       isolate);
-  Handle<JSGlobalObject> global_object(native_context->global_object(),
-                                       isolate);
-  Handle<ScriptContextTable> script_context_table(
-      native_context->script_context_table(), isolate);
-
-  Object name_clash_result =
-      FindNameClash(isolate, scope_info, global_object, script_context_table);
-  if (isolate->has_pending_exception()) return name_clash_result;
-
-  Handle<Context> result =
-      isolate->factory()->NewScriptContext(native_context, scope_info);
-
-  Handle<ScriptContextTable> new_script_context_table =
-      ScriptContextTable::Extend(script_context_table, result);
-  native_context->set_script_context_table(*new_script_context_table);
-  return *result;
-}
-
 RUNTIME_FUNCTION(Runtime_NewFunctionContext) {
   HandleScope scope(isolate);
   DCHECK_EQ(1, args.length());

src/runtime/runtime.h

@@ -396,7 +396,6 @@ namespace internal {
   F(NewClosure_Tenured, 2, 1)               \
   F(NewFunctionContext, 1, 1)               \
   F(NewRestParameter, 1, 1)                 \
-  F(NewScriptContext, 1, 1)                 \
   F(NewSloppyArguments, 3, 1)               \
   F(NewSloppyArguments_Generic, 1, 1)       \
   F(NewStrictArguments, 1, 1)               \

test/inspector/console/scoped-variables-expected.txt

@@ -15,7 +15,7 @@ Evaluating 'let a = 239;'
         columnNumber : 0
         exception : {
             className : SyntaxError
-            description : SyntaxError: Identifier 'a' has already been declared     at <anonymous>:1:1
+            description : SyntaxError: Identifier 'a' has already been declared
             objectId : <objectId>
             subtype : error
             type : object
@@ -27,7 +27,7 @@ Evaluating 'let a = 239;'
     }
     result : {
         className : SyntaxError
-        description : SyntaxError: Identifier 'a' has already been declared     at <anonymous>:1:1
+        description : SyntaxError: Identifier 'a' has already been declared
         objectId : <objectId>
         subtype : error
         type : object