[openmp] Workaround bug in old Android pthread_attr_setstacksize

Round the stack size to a multiple of the page size. Older versions of
Android (until KitKat) would fail pthread_attr_setstacksize with
EINVAL if the stack size was not a multiple of the page size.

Patch by Dan Albert <[email protected]>.

Test: Build, copied into the NDK, passed openmp test on ICS.
Bug: android/ndk#9
llvm-svn: 367070

Author: kongy

openmp/runtime/src/z_Linux_util.cpp

@@ -802,6 +802,13 @@ void __kmp_create_worker(int gtid, kmp_info_t *th, size_t stack_size) {
      and also gives the user the stack space they requested for all threads */
   stack_size += gtid * __kmp_stkoffset * 2;
 
+#if defined(__ANDROID__) && __ANDROID_API__ < 19
+    // Round the stack size to a multiple of the page size. Older versions of
+    // Android (until KitKat) would fail pthread_attr_setstacksize with EINVAL
+    // if the stack size was not a multiple of the page size.
+    stack_size = (stack_size + PAGE_SIZE - 1) & ~(PAGE_SIZE - 1);
+#endif
+
   KA_TRACE(10, ("__kmp_create_worker: T#%d, default stacksize = %lu bytes, "
                 "__kmp_stksize = %lu bytes, final stacksize = %lu bytes\n",
                 gtid, KMP_DEFAULT_STKSIZE, __kmp_stksize, stack_size));