Add a flag to help platform ports bootstrap V8

src/code-stubs-hydrogen.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/code-stubs.h"
 
 #include <memory>
 
 #include "src/bailout-reason.h"
 #include "src/crankshaft/hydrogen.h"
@@ skipping 230 matching lines @@
   // Create the code object.
   CodeDesc desc;
   masm.GetCode(&desc);
 
   // Copy the generated code into a heap object.
   Handle<Code> new_object = factory->NewCode(
       desc, GetCodeFlags(), masm.CodeObject(), NeedsImmovableCode());
   return new_object;
 }
 
+Handle<Code> HydrogenCodeStub::GenerateRuntimeTailCall(
+    CodeStubDescriptor* descriptor) {
+  const char* name = CodeStub::MajorName(MajorKey());
+  Zone zone(isolate()->allocator());
+  CallInterfaceDescriptor interface_descriptor(GetCallInterfaceDescriptor());
+  CodeStubAssembler assembler(isolate(), &zone, interface_descriptor,
+                              GetCodeFlags(), name);
+  int total_params = interface_descriptor.GetStackParameterCount() +
+                     interface_descriptor.GetRegisterParameterCount();
+  switch (total_params) {
+    case 0:
+      assembler.TailCallRuntime(descriptor->miss_handler_id(),
+                                assembler.Parameter(0));
+      break;
+    case 1:
+      assembler.TailCallRuntime(descriptor->miss_handler_id(),
+                                assembler.Parameter(1), assembler.Parameter(0));
+      break;
+    case 2:
+      assembler.TailCallRuntime(descriptor->miss_handler_id(),
+                                assembler.Parameter(2), assembler.Parameter(0),
+                                assembler.Parameter(1));
+      break;
+    case 3:
+      assembler.TailCallRuntime(descriptor->miss_handler_id(),
+                                assembler.Parameter(3), assembler.Parameter(0),
+                                assembler.Parameter(1), assembler.Parameter(2));
+      break;
+    case 4:
+      assembler.TailCallRuntime(descriptor->miss_handler_id(),
+                                assembler.Parameter(4), assembler.Parameter(0),
+                                assembler.Parameter(1), assembler.Parameter(2),
+                                assembler.Parameter(3));
+      break;
+    default:
+      UNIMPLEMENTED();
+      break;
+  }
+  return assembler.GenerateCode();
+}
 
 template <class Stub>
 static Handle<Code> DoGenerateCode(Stub* stub) {
   Isolate* isolate = stub->isolate();
   CodeStubDescriptor descriptor(stub);
 
+  if (FLAG_minimal && descriptor.has_miss_handler()) {
+    return stub->GenerateRuntimeTailCall(&descriptor);
+  }
+
   // If we are uninitialized we can use a light-weight stub to enter
   // the runtime that is significantly faster than using the standard
   // stub-failure deopt mechanism.
   if (stub->IsUninitialized() && descriptor.has_miss_handler()) {
     DCHECK(!descriptor.stack_parameter_count().is_valid());
     return stub->GenerateLightweightMissCode(descriptor.miss_handler());
   }
   base::ElapsedTimer timer;
   if (FLAG_profile_hydrogen_code_stub_compilation) {
     timer.Start();
@@ skipping 1836 matching lines @@
   return Pop();
 }
 
 
 Handle<Code> KeyedLoadGenericStub::GenerateCode() {
   return DoGenerateCode(this);
 }
 
 }  // namespace internal
 }  // namespace v8