Array length reduction should throw in strict mode if it can't delete an element.

src/ic/x64/handler-compiler-x64.cc

 // 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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/ic/call-optimization.h"
 #include "src/ic/handler-compiler.h"
 #include "src/ic/ic.h"
 #include "src/isolate-inl.h"
@@ skipping 575 matching lines @@
     GenerateRestoreName(miss, name);
     if (IC::ICUseVector(kind())) PopVectorAndSlot();
     TailCallBuiltin(masm(), MissBuiltin(kind()));
     __ bind(&success);
   }
 }
 
 
 void NamedLoadHandlerCompiler::GenerateLoadCallback(
     Register reg, Handle<AccessorInfo> callback) {
+  DCHECK(!AreAliased(kScratchRegister, scratch2(), scratch3(), receiver()));
+  DCHECK(!AreAliased(kScratchRegister, scratch2(), scratch3(), reg));
+
   // Insert additional parameters into the stack frame above return address.
-  DCHECK(!scratch4().is(reg));
-  __ PopReturnAddressTo(scratch4());
+  __ PopReturnAddressTo(scratch3());
 
-  STATIC_ASSERT(PropertyCallbackArguments::kHolderIndex == 0);
-  STATIC_ASSERT(PropertyCallbackArguments::kIsolateIndex == 1);
-  STATIC_ASSERT(PropertyCallbackArguments::kReturnValueDefaultValueIndex == 2);
-  STATIC_ASSERT(PropertyCallbackArguments::kReturnValueOffset == 3);
-  STATIC_ASSERT(PropertyCallbackArguments::kDataIndex == 4);
-  STATIC_ASSERT(PropertyCallbackArguments::kThisIndex == 5);
-  STATIC_ASSERT(PropertyCallbackArguments::kArgsLength == 6);
+  // Build v8::PropertyCallbackInfo::args_ array on the stack and push property
+  // name below the exit frame to make GC aware of them.
+  STATIC_ASSERT(PropertyCallbackArguments::kShouldThrowOnErrorIndex == 0);
+  STATIC_ASSERT(PropertyCallbackArguments::kHolderIndex == 1);
+  STATIC_ASSERT(PropertyCallbackArguments::kIsolateIndex == 2);
+  STATIC_ASSERT(PropertyCallbackArguments::kReturnValueDefaultValueIndex == 3);
+  STATIC_ASSERT(PropertyCallbackArguments::kReturnValueOffset == 4);
+  STATIC_ASSERT(PropertyCallbackArguments::kDataIndex == 5);
+  STATIC_ASSERT(PropertyCallbackArguments::kThisIndex == 6);
+  STATIC_ASSERT(PropertyCallbackArguments::kArgsLength == 7);
+
   __ Push(receiver());  // receiver
   Handle<Object> data(callback->data(), isolate());
   if (data->IsUndefined() || data->IsSmi()) {
     __ Push(data);
   } else {
-    DCHECK(!scratch2().is(reg));
     Handle<WeakCell> cell =
         isolate()->factory()->NewWeakCell(Handle<HeapObject>::cast(data));
     // The callback is alive if this instruction is executed,
     // so the weak cell is not cleared and points to data.
     __ GetWeakValue(scratch2(), cell);
     __ Push(scratch2());
   }
-  DCHECK(!kScratchRegister.is(reg));
   __ LoadRoot(kScratchRegister, Heap::kUndefinedValueRootIndex);
   __ Push(kScratchRegister);  // return value
   __ Push(kScratchRegister);  // return value default
   __ PushAddress(ExternalReference::isolate_address(isolate()));
   __ Push(reg);     // holder
+  __ Push(Smi::FromInt(0));  // should_throw_on_error -> false
+
   __ Push(name());  // name
-  // Save a pointer to where we pushed the arguments pointer.  This will be
-  // passed as the const PropertyAccessorInfo& to the C++ callback.
-
-  __ PushReturnAddressFrom(scratch4());
+  __ PushReturnAddressFrom(scratch3());
 
   // Abi for CallApiGetter
   Register api_function_address = ApiGetterDescriptor::function_address();
   Address getter_address = v8::ToCData<Address>(callback->getter());
   __ Move(api_function_address, getter_address, RelocInfo::EXTERNAL_REFERENCE);
 
   CallApiGetterStub stub(isolate());
   __ TailCallStub(&stub);
 }
 
@@ skipping 74 matching lines @@
   __ PopReturnAddressTo(scratch2());
   PushInterceptorArguments(masm(), receiver(), holder_reg, this->name(),
                            holder());
   __ PushReturnAddressFrom(scratch2());
 
   __ TailCallRuntime(Runtime::kLoadPropertyWithInterceptor);
 }
 
 
 Handle<Code> NamedStoreHandlerCompiler::CompileStoreCallback(
-    Handle<JSObject> object, Handle<Name> name, Handle<AccessorInfo> callback) {
+    Handle<JSObject> object, Handle<Name> name, Handle<AccessorInfo> callback,
+    LanguageMode language_mode) {
   Register holder_reg = Frontend(name);
 
   __ PopReturnAddressTo(scratch1());
   __ Push(receiver());
   __ Push(holder_reg);
   // If the callback cannot leak, then push the callback directly,
   // otherwise wrap it in a weak cell.
   if (callback->data()->IsUndefined() || callback->data()->IsSmi()) {
     __ Push(callback);
   } else {
     Handle<WeakCell> cell = isolate()->factory()->NewWeakCell(callback);
     __ Push(cell);
   }
   __ Push(name);
   __ Push(value());
+  __ Push(Smi::FromInt(language_mode));
   __ PushReturnAddressFrom(scratch1());
 
   // Do tail-call to the runtime system.
   __ TailCallRuntime(Runtime::kStoreCallbackProperty);
 
   // Return the generated code.
   return GetCode(kind(), Code::FAST, name);
 }
 
 
@@ skipping 53 matching lines @@
   // Return the generated code.
   return GetCode(kind(), Code::NORMAL, name);
 }
 
 
 #undef __
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64