VM: Use constant pool also for leaf runtime calls on x64, arm, arm64 and mips.

runtime/vm/runtime_entry_x64.cc

 // Copyright (c) 2011, 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_X64)
 
 #include "vm/runtime_entry.h"
 
 #include "vm/assembler.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:
 //   RSP : points to the arguments and return value array.
 //   RBX : address of the runtime function to call.
 //   R10 : number of arguments to the call.
 void RuntimeEntry::Call(Assembler* assembler, intptr_t argument_count) const {
   if (is_leaf()) {
     ASSERT(argument_count == this->argument_count());
     ExternalLabel label(GetEntryPoint());
-    __ CallCFunction(&label);
+    COMPILE_ASSERT(CallingConventions::kVolatileCpuRegisters & (1 << RAX));
+    __ LoadExternalLabel(RAX, &label, kNotPatchable);
+    __ CallCFunction(RAX);
   } else {
     // Argument count is not checked here, but in the runtime entry for a more
     // informative error message.
     ExternalLabel label(GetEntryPoint());
     __ LoadExternalLabel(RBX, &label, kNotPatchable);
     __ movq(R10, Immediate(argument_count));
     __ Call(*StubCode::CallToRuntime_entry());
   }
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64