Partially implement DBC profiler.

runtime/vm/signal_handler_macos.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"
 #include "vm/instructions.h"
 #include "vm/simulator.h"
 #include "vm/signal_handler.h"
 #if defined(TARGET_OS_MACOS)
 
@@ skipping 61 matching lines @@
   return static_cast<uintptr_t>(mcontext->__ss.__x[SPREG]);
 #else
   return GetCStackPointer(mcontext);
 #endif
 }
 
 
 uintptr_t SignalHandler::GetLinkRegister(const mcontext_t& mcontext) {
   uintptr_t lr = 0;
 
-#if defined(TARGET_ARCH_IA32)
+#if defined(HOST_ARCH_IA32)
   lr = 0;
-#elif defined(TARGET_ARCH_X64)
+#elif defined(HOST_ARCH_X64)
   lr = 0;
-#elif defined(TARGET_ARCH_MIPS) && defined(USING_SIMULATOR)
-  lr = 0;
-#elif defined(TARGET_ARCH_ARM) && defined(USING_SIMULATOR)
-  lr = 0;
-#elif defined(TARGET_ARCH_ARM64) && defined(USING_SIMULATOR)
-  lr = 0;
-#elif defined(TARGET_ARCH_ARM)
-  lr = 0;
-#elif defined(TARGET_ARCH_ARM64)
-  lr = 0;
-#elif defined(TARGET_ARCH_MIPS)
-  lr = 0;
+#elif defined(HOST_ARCH_ARM)
+  lr = static_cast<uintptr_t>(mcontext->__ss.__lr);
+#elif defined(HOST_ARCH_ARM64)
+  lr = static_cast<uintptr_t>(mcontext->__ss.__lr);
 #else
-  UNIMPLEMENTED();
-#endif  // TARGET_ARCH_...
+#error Unsupported architecture.
+#endif  // HOST_ARCH_...
 
   return lr;
 }
 
 
 void SignalHandler::InstallImpl(SignalAction action) {
   struct sigaction act;
   act.sa_handler = NULL;
   act.sa_sigaction = action;
   sigemptyset(&act.sa_mask);
@@ skipping 11 matching lines @@
   sigemptyset(&act.sa_mask);
   act.sa_flags = 0;
   int r = sigaction(SIGPROF, &act, NULL);
   ASSERT(r == 0);
 }
 
 
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_MACOS)