Implement PC, FP, and SP getters on Linux ARM

runtime/vm/signal_handler_linux.cc

Index: runtime/vm/signal_handler_linux.cc
diff --git a/runtime/vm/signal_handler_linux.cc b/runtime/vm/signal_handler_linux.cc
index d4021cf24928f3a6eaff5b1e520e5f6499ca4f1a..4345dd47ab47954a691f7b3440f83869f478063a 100644
--- a/runtime/vm/signal_handler_linux.cc
+++ b/runtime/vm/signal_handler_linux.cc
@@ -20,6 +20,8 @@ uintptr_t SignalHandler::GetProgramCounter(const mcontext_t& mcontext) {
   pc = static_cast<uintptr_t>(mcontext.gregs[REG_EIP]);
 #elif defined(TARGET_ARCH_ARM) && defined(USING_SIMULATOR)
   pc = static_cast<uintptr_t>(mcontext.gregs[REG_EIP]);
+#elif defined(TARGET_ARCH_ARM)
+  pc = static_cast<uintptr_t>(mcontext.arm_pc);
 #else
   UNIMPLEMENTED();
 #endif  // TARGET_ARCH_...
@@ -38,6 +40,8 @@ uintptr_t SignalHandler::GetFramePointer(const mcontext_t& mcontext) {
   fp = static_cast<uintptr_t>(mcontext.gregs[REG_EBP]);
 #elif defined(TARGET_ARCH_ARM) && defined(USING_SIMULATOR)
   fp = static_cast<uintptr_t>(mcontext.gregs[REG_EBP]);
+#elif defined(TARGET_ARCH_ARM)
+  fp = static_cast<uintptr_t>(mcontext.arm_fp);
 #else
   UNIMPLEMENTED();
 #endif  // TARGET_ARCH_...
@@ -57,6 +61,8 @@ uintptr_t SignalHandler::GetStackPointer(const mcontext_t& mcontext) {
   sp = static_cast<uintptr_t>(mcontext.gregs[REG_ESP]);
 #elif defined(TARGET_ARCH_ARM) && defined(USING_SIMULATOR)
   sp = static_cast<uintptr_t>(mcontext.gregs[REG_ESP]);
+#elif defined(TARGET_ARCH_ARM)
+  sp = static_cast<uintptr_t>(mcontext.arm_sp);
 #else
   UNIMPLEMENTED();
 #endif  // TARGET_ARCH_...