[stubs] Turn FastCloneRegExpStub into a TurboFan code stub.

src/full-codegen/full-codegen.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.
 
 #include "src/full-codegen/full-codegen.h"
 
 #include "src/ast/ast-numbering.h"
 #include "src/ast/ast.h"
 #include "src/ast/prettyprinter.h"
 #include "src/ast/scopes.h"
@@ skipping 1477 matching lines @@
   Comment cmnt(masm_, "[ RegExpLiteral");
   Callable callable = CodeFactory::FastCloneRegExp(isolate());
   CallInterfaceDescriptor descriptor = callable.descriptor();
   LoadFromFrameField(JavaScriptFrameConstants::kFunctionOffset,
                      descriptor.GetRegisterParameter(0));
   __ Move(descriptor.GetRegisterParameter(1),
           Smi::FromInt(expr->literal_index()));
   __ Move(descriptor.GetRegisterParameter(2), expr->pattern());
   __ Move(descriptor.GetRegisterParameter(3), Smi::FromInt(expr->flags()));
   __ Call(callable.code(), RelocInfo::CODE_TARGET);
+
+  // Reload the context register after the call as i.e. TurboFan code stubs
+  // won't preserve the context register.
+  LoadFromFrameField(StandardFrameConstants::kContextOffset,
+                     context_register());
   context()->Plug(result_register());
 }
 
 void FullCodeGenerator::VisitNativeFunctionLiteral(
     NativeFunctionLiteral* expr) {
   Comment cmnt(masm_, "[ NativeFunctionLiteral");
   Handle<SharedFunctionInfo> shared =
       Compiler::GetSharedFunctionInfoForNative(expr->extension(), expr->name());
   EmitNewClosure(shared, false);
 }
@@ skipping 423 matching lines @@
   return var->scope()->is_nonlinear() ||
          var->initializer_position() >= proxy->position();
 }
 
 
 #undef __
 
 
 }  // namespace internal
 }  // namespace v8