[turbofan] Rewrite ToObject as TurboFan stub.

src/full-codegen/mips/full-codegen-mips.cc

 // Copyright 2012 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_MIPS
 
 // Note on Mips implementation:
 //
 // The result_register() for mips is the 'v0' register, which is defined
 // by the ABI to contain function return values. However, the first
@@ skipping 983 matching lines @@
   __ GetObjectType(a0, a1, a1);
   __ Branch(USE_DELAY_SLOT, &done_convert, ge, a1,
             Operand(FIRST_JS_RECEIVER_TYPE));
   __ LoadRoot(at, Heap::kNullValueRootIndex);  // In delay slot.
   __ Branch(USE_DELAY_SLOT, &exit, eq, a0, Operand(at));
   __ LoadRoot(at, Heap::kUndefinedValueRootIndex);  // In delay slot.
   __ Branch(&exit, eq, a0, Operand(at));
   __ bind(&convert);
   ToObjectStub stub(isolate());
   __ CallStub(&stub);
+  RestoreContext();
   __ mov(a0, v0);
   __ bind(&done_convert);
   PrepareForBailoutForId(stmt->ToObjectId(), BailoutState::TOS_REGISTER);
   __ push(a0);
 
   // Check cache validity in generated code. If we cannot guarantee cache
   // validity, call the runtime system to check cache validity or get the
   // property names in a fixed array. Note: Proxies never have an enum cache,
   // so will always take the slow path.
   Label call_runtime;
@@ skipping 2764 matching lines @@
          reinterpret_cast<uint32_t>(
              isolate->builtins()->OnStackReplacement()->entry()));
   return ON_STACK_REPLACEMENT;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS