1// RUN: %libomp-compile-and-run
2
3// https://bugs.llvm.org/show_bug.cgi?id=26540 requested
4// stack size to be propagated from master to workers.
5// Library implements propagation of not too big stack
6// for Linux x86_64 platform (skipped Windows for now).
7//
8// The test checks that workers can use more than 4MB
9// of stack (4MB - was historical default for
10// stack size of worker thread in runtime library).
11
12#include <stdio.h>
13#include <omp.h>
14#if !defined(_WIN32)
15#include <sys/resource.h> // getrlimit
16#endif
17
18#define STK 4800000
19
20double foo(int n, int th)
21{
22 double arr[n];
23 int i;
24 double res = 0.0;
25 for (i = 0; i < n; ++i) {
26 arr[i] = (double)i / (n + 2);
27 }
28 for (i = 0; i < n; ++i) {
29 res += arr[i] / n;
30 }
31 return res;
32}
33
34int main(int argc, char *argv[])
35{
36#if defined(_WIN32)
37 // don't test Windows
38 printf("stack propagation not implemented, skipping test...\n");
39 return 0;
40#else
41 int status;
42 double val = 0.0;
43 int m = STK / 8; // > 4800000 bytes per thread
44 // read stack size of calling thread, save it as default
45 struct rlimit rlim;
46 status = getrlimit(RLIMIT_STACK, rlimits: &rlim);
47 if (sizeof(void *) > 4 && // do not test 32-bit systems,
48 status == 0 && rlim.rlim_cur > STK) { // or small initial stack size
49#pragma omp parallel reduction(+:val)
50 {
51 val += foo(n: m, th: omp_get_thread_num());
52 }
53 } else {
54 printf(format: "too small stack size limit (needs about 8MB), skipping test...\n");
55 return 0;
56 }
57 if (val > 0.1) {
58 printf(format: "passed\n");
59 return 0;
60 } else {
61 printf(format: "failed, val = %f\n", val);
62 return 1;
63 }
64#endif // _WIN32
65}
66

source code of openmp/runtime/test/misc_bugs/stack-propagate.c