Also time external callbacks from generated code.

src/arm/macro-assembler-arm.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2204 matching lines @@
       next_address);
 
   // Allocate HandleScope in callee-save registers.
   mov(r7, Operand(next_address));
   ldr(r4, MemOperand(r7, kNextOffset));
   ldr(r5, MemOperand(r7, kLimitOffset));
   ldr(r6, MemOperand(r7, kLevelOffset));
   add(r6, r6, Operand(1));
   str(r6, MemOperand(r7, kLevelOffset));
 
+  if (FLAG_log_timer_events) {
+    FrameScope frame(this, StackFrame::MANUAL);
+    PushSafepointRegisters();
+    PrepareCallCFunction(0, r0);
+    CallCFunction(ExternalReference::log_enter_external_function(isolate()), 0);
+    PopSafepointRegisters();
+  }
+
   // Native call returns to the DirectCEntry stub which redirects to the
   // return address pushed on stack (could have moved after GC).
   // DirectCEntry stub itself is generated early and never moves.
   DirectCEntryStub stub;
   stub.GenerateCall(this, function);
 
+  if (FLAG_log_timer_events) {
+    FrameScope frame(this, StackFrame::MANUAL);
+    PushSafepointRegisters();
+    PrepareCallCFunction(0, r0);
+    CallCFunction(ExternalReference::log_leave_external_function(isolate()), 0);
+    PopSafepointRegisters();
+  }
+
   Label promote_scheduled_exception;
   Label delete_allocated_handles;
   Label leave_exit_frame;
 
   // If result is non-zero, dereference to get the result value
   // otherwise set it to undefined.
   cmp(r0, Operand(0));
   LoadRoot(r0, Heap::kUndefinedValueRootIndex, eq);
   ldr(r0, MemOperand(r0), ne);
 
@@ skipping 1643 matching lines @@
 void CodePatcher::EmitCondition(Condition cond) {
   Instr instr = Assembler::instr_at(masm_.pc_);
   instr = (instr & ~kCondMask) | cond;
   masm_.emit(instr);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM