[OMPT] Use alloca() to force availability of frame pointer

[sconvent]

Summary

When compiling with icc, there is a problem with reenter frame addresses in parallel_begin callbacks in the interoperability.c testcase. (The address is not available. thus NULL)
Using alloca() forces availability of the frame pointer.

[protze.joachim]

The problem, which gets visible in this test case is the use of __builtin_frame_address(1), which is documented to be not safe.
Is there a better way to get the canonical frame address of the calling function? Also the address returned by __builtin_frame_address seems to be different from the canonical frame address. How can we get the requested address?

[hbae]

runtime/test/ompt/misc/interoperability.cpp

13 ↗

(On Diff #151712)

Can you try to insert an alloca() call here? It can force using the frame pointer in many cases (compilers).

void *p = alloca(0);

[sconvent]

Use alloca() to force availability of frame pointer

[sconvent]

Add comment explaining the use of alloca()

[hbae]

LGTM

openmp/trunk/runtime/test/ompt/misc/interoperability.cpp

 // RUN: %libomp-cxx-compile-and-run | %sort-threads | FileCheck %s
 // REQUIRES: ompt
 
 #include <iostream>
 #include <thread>
+#include <alloca.h>
 
 #include "callback.h"
 #include "omp.h"
 
 int condition = 0;
 
 void f() {
   // Call OpenMP API function to force initialization of OMPT.
   // (omp_get_thread_num() does not work because it just returns 0 if the
   // runtime isn't initialized yet...)
   omp_get_num_threads();
 
+  // Call alloca() to force availability of frame pointer
+  void *p = alloca(0);
+
   OMPT_SIGNAL(condition);
   // Wait for both initial threads to arrive that will eventually become the
   // master threads in the following parallel region.
   OMPT_WAIT(condition, 2);
 
 #pragma omp parallel num_threads(2)
   {
     // Wait for all threads to arrive so that no worker thread can be reused...