Contribution of PowerPC port (continuation of 422063005) - AIX Common1

src/sampler.cc

Index: src/sampler.cc
diff --git a/src/sampler.cc b/src/sampler.cc
index 19c5cacee6bbc6398507fd45e1df2e47e986872e..a7d7f349d69c2009a8a4b6efcb651d46b1e5c4be 100644
--- a/src/sampler.cc
+++ b/src/sampler.cc
@@ -13,7 +13,7 @@
 #include <signal.h>
 #include <sys/time.h>
 
-#if !V8_OS_QNX && !V8_OS_NACL
+#if !(V8_OS_QNX || V8_OS_AIX) && !V8_OS_NACL

[Sven Panne, 2015/01/27 11:47:06]

De Morgan's law, please. :-)

[michael_dawson, 2015/01/29 00:08:29]

Will do 

 #include <sys/syscall.h>  // NOLINT
 #endif
 
@@ -311,6 +311,10 @@ class SignalHandler : public AllStatic {
   static void Restore() {
 #if !V8_OS_NACL
     if (signal_handler_installed_) {
+#if V8_OS_AIX
+      // Ensure delivery of any pending SIGPROF before removing the handler

[Sven Panne, 2015/01/27 11:47:06]

Hmmm, why is this AIX-specific? Why can't there be yet another SIGPROF after the
handler and coming back to the yield?

In a nutshell: This looks wrong, like 99.9% of all yield uses I've seen so far.
:-) If it's really OK, we need an extensive comment here.

[michael_dawson, 2015/01/29 00:08:29]

We went to validate our explanation of why it was needed, but we can no longer
recreate the issue with the current level so we will remove

+      base::Thread::YieldCPU();
+#endif
       sigaction(SIGPROF, &old_signal_handler_, 0);
       signal_handler_installed_ = false;
     }
@@ -479,7 +483,11 @@ void SignalHandler::HandleProfilerSignal(int signal, siginfo_t* info,
   state.sp = reinterpret_cast<Address>(mcontext.cpu.gpr[ARM_REG_SP]);
   state.fp = reinterpret_cast<Address>(mcontext.cpu.gpr[ARM_REG_FP]);
 #endif  // V8_HOST_ARCH_*
-#endif  // V8_OS_QNX
+#elif V8_OS_AIX
+  state.pc = reinterpret_cast<Address>(mcontext.jmp_context.iar);
+  state.sp = reinterpret_cast<Address>(mcontext.jmp_context.gpr[1]);
+  state.fp = reinterpret_cast<Address>(mcontext.jmp_context.gpr[31]);
+#endif  // V8_OS_AIX
 #endif  // USE_SIMULATOR
   sampler->SampleStack(state);
 }