[turbofan] Add the StackSlot operator to turbofan.

src/compiler/mips64/code-generator-mips64.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.
 
 #include "src/ast/scopes.h"
 #include "src/compiler/code-generator.h"
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/osr.h"
@@ skipping 617 matching lines @@
       auto ool = new (zone()) OutOfLineRecordWrite(this, object, index, value,
                                                    scratch0, scratch1, mode);
       __ Daddu(at, object, index);
       __ sd(value, MemOperand(at));
       __ CheckPageFlag(object, scratch0,
                        MemoryChunk::kPointersFromHereAreInterestingMask, ne,
                        ool->entry());
       __ bind(ool->exit());
       break;
     }
+    case kArchStackSlot: {
+      FrameOffset offset =
+          frame_access_state()->GetFrameOffset(i.InputInt32(0));
+      __ Daddu(i.OutputRegister(), offset.from_stack_pointer() ? sp : fp,
+               Operand(offset.offset()));
+      break;
+    }
     case kMips64Add:
       __ Addu(i.OutputRegister(), i.InputRegister(0), i.InputOperand(1));
       break;
     case kMips64Dadd:
       __ Daddu(i.OutputRegister(), i.InputRegister(0), i.InputOperand(1));
       break;
     case kMips64DaddOvf:
       // Pseudo-instruction used for overflow/branch. No opcode emitted here.
       break;
     case kMips64Sub:
@@ skipping 1469 matching lines @@
       padding_size -= v8::internal::Assembler::kInstrSize;
     }
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8