[OpenMP] target_data_begin: fail on device alloc fail

Without this patch, target_data_begin continues after an illegal
mapping or an out-of-memory error on the device.  With this patch, it
terminates the runtime with an error instead.

The new test exercises only illegal mappings.  I didn't think of a
good way to exercise out-of-memory errors from the test suite.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D78170

Author: jdenny-ornl

openmp/libomptarget/src/omptarget.cpp

@@ -286,6 +286,7 @@ int target_data_begin(DeviceTy &Device, int32_t arg_num, void **args_base,
       // NULL, so getOrAlloc() returning NULL is not an error.
       DP("Call to getOrAllocTgtPtr returned null pointer (device failure or "
           "illegal mapping).\n");
+      return OFFLOAD_FAIL;
     }
     DP("There are %" PRId64 " bytes allocated at target address " DPxMOD
         " - is%s new\n", data_size, DPxPTR(TgtPtrBegin),

openmp/libomptarget/test/mapping/alloc_fail.c

@@ -0,0 +1,25 @@
+// RUN: %libomptarget-compile-aarch64-unknown-linux-gnu
+// RUN: %libomptarget-run-fail-aarch64-unknown-linux-gnu 2>&1 \
+// RUN: | %fcheck-aarch64-unknown-linux-gnu
+
+// RUN: %libomptarget-compile-powerpc64-ibm-linux-gnu
+// RUN: %libomptarget-run-fail-powerpc64-ibm-linux-gnu 2>&1 \
+// RUN: | %fcheck-powerpc64-ibm-linux-gnu
+
+// RUN: %libomptarget-compile-powerpc64le-ibm-linux-gnu
+// RUN: %libomptarget-run-fail-powerpc64le-ibm-linux-gnu 2>&1 \
+// RUN: | %fcheck-powerpc64le-ibm-linux-gnu
+
+// RUN: %libomptarget-compile-x86_64-pc-linux-gnu
+// RUN: %libomptarget-run-fail-x86_64-pc-linux-gnu 2>&1 \
+// RUN: | %fcheck-x86_64-pc-linux-gnu
+
+// CHECK: Libomptarget fatal error 1: failure of target construct while offloading is mandatory
+
+int main() {
+  int arr[4] = {0, 1, 2, 3};
+#pragma omp target data map(alloc: arr[0:2])
+#pragma omp target data map(alloc: arr[1:2])
+  ;
+  return 0;
+}