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

runtime/vm/runtime_entry_arm64.cc

 // Copyright (c) 2014, 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_ARM64)
 
 #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.
 //   R5 : address of the runtime function to call.
-//   R4 : number of arguments to the call as Smi.
+//   R4 : 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 8 arguments passed
   // in registers.
   ASSERT(argument_count >= 0);
   ASSERT(!is_leaf() || (argument_count <= 8));
@@ skipping 16 matching lines @@
     __ mov(R26, SP);
     __ ReserveAlignedFrameSpace(0);
     __ mov(CSP, SP);
     __ BranchLink(&label, kNoPP);
     __ mov(SP, R26);
     __ mov(CSP, R25);
   } else {
     // Argument count is not checked here, but in the runtime entry for a more
     // informative error message.
     __ LoadImmediate(R5, entry, kNoPP);
-    __ LoadImmediate(R4, Smi::RawValue(argument_count), kNoPP);
+    __ LoadImmediate(R4, argument_count, kNoPP);
     __ BranchLink(&StubCode::CallToRuntimeLabel(), PP);
   }
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64