Implement function calls on ARM using the blx instruction when available. Usi...

src/arm/debug-arm.cc

Index: src/arm/debug-arm.cc
===================================================================
--- src/arm/debug-arm.cc	(revision 4189)
+++ src/arm/debug-arm.cc	(working copy)
@@ -46,13 +46,23 @@
   //   add sp, sp, #4
   //   bx lr
   // to a call to the debug break return code.
+  // #if USE_BLX
+  //   ldr ip, [pc, #0]
+  //   blx ip
+  // #else
   //   mov lr, pc
   //   ldr pc, [pc, #-4]
+  // #endif
   //   <debug break return code entry point address>
   //   bktp 0
   CodePatcher patcher(rinfo()->pc(), 4);
+#ifdef USE_BLX
+  patcher.masm()->ldr(v8::internal::ip, MemOperand(v8::internal::pc, 0));
+  patcher.masm()->blx(v8::internal::ip);
+#else
   patcher.masm()->mov(v8::internal::lr, v8::internal::pc);
   patcher.masm()->ldr(v8::internal::pc, MemOperand(v8::internal::pc, -4));
+#endif
   patcher.Emit(Debug::debug_break_return()->entry());
   patcher.masm()->bkpt(0);
 }