Specialize breakpoint stubs by set of live registers of the stubs they are intercepting.

runtime/vm/runtime_entry_mips.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_MIPS)
 
 #include "vm/runtime_entry.h"
 
 #include "vm/assembler.h"
 #include "vm/simulator.h"
 #include "vm/stub_code.h"
 
 namespace dart {
 
 #define __ assembler->
 
 
 // Generate code to call into the stub which will call the runtime
 // function. Input for the stub is as follows:
 //   SP : points to the arguments and return value array.
 //   S5 : address of the runtime function to call.
-//   S4 : number of arguments to the call as Smi.
+//   S4 : number of arguments to the call.
 void RuntimeEntry::Call(Assembler* assembler, intptr_t argument_count) const {
   // Compute the effective address. When running under the simulator,
   // this is a redirection address that forces the simulator to call
   // into the runtime system.
   uword entry = GetEntryPoint();
 #if defined(USING_SIMULATOR)
   // Redirection to leaf runtime calls supports a maximum of 4 arguments passed
   // in registers (maximum 2 double arguments for leaf float runtime calls).
   ASSERT(argument_count >= 0);
   ASSERT(!is_leaf() ||
          (!is_float() && (argument_count <= 4)) ||
          (argument_count <= 2));
   Simulator::CallKind call_kind =
       is_leaf() ? (is_float() ? Simulator::kLeafFloatRuntimeCall
                               : Simulator::kLeafRuntimeCall)
                 : Simulator::kRuntimeCall;
   entry =
       Simulator::RedirectExternalReference(entry, call_kind, argument_count);
 #endif
   if (is_leaf()) {
     ASSERT(argument_count == this->argument_count());
     ExternalLabel label(entry);
     __ BranchLink(&label);
   } else {
     // Argument count is not checked here, but in the runtime entry for a more
     // informative error message.
     __ LoadImmediate(S5, entry);
-    __ LoadImmediate(S4, Smi::RawValue(argument_count));
+    __ LoadImmediate(S4, argument_count);
     __ BranchLink(&StubCode::CallToRuntimeLabel());
   }
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS