[Frontend] Allow OpenMP offloading to aarch64

[bryanpkc]

Summary

D30644 added OpenMP offloading to AArch64 targets, then D32035 changed the
frontend to throw an error when offloading is requested for an unsupported
target architecture. However the latter did not include AArch64 in the list
of supported architectures, causing the following unit tests to fail:

libomptarget :: api/omp_get_num_devices.c
libomptarget :: mapping/pr38704.c
libomptarget :: offloading/offloading_success.c
libomptarget :: offloading/offloading_success.cpp

[jdoerfert]

LGTM.

[ABataev]

Tests are required

[bryanpkc]

In D70804#1763289, @ABataev wrote:

Tests are required

The tests for this were added in D30644, but they are currently failing on AArch64 due to D32035. This patch allows those tests to pass again. What further testing should I add?

[Hahnfeld]

In D70804#1763443, @bryanpkc wrote:

In D70804#1763289, @ABataev wrote:

Tests are required

The tests for this were added in D30644, but they are currently failing on AArch64 due to D32035. This patch allows those tests to pass again. What further testing should I add?

There should be tests in Clang that the target is indeed supported. Tests in libomptarget are fine, but apparently they are not tested on a regular basis when failing for more than two years.

[bryanpkc]

Add tests for -fopenmp-targets=.

[bryanpkc]

Pinging reviewers.

[ABataev]

clang/test/OpenMP/target_messages.cpp

4 ↗

(On Diff #231582)

Why do you need the changes in this file?

[bryanpkc]

clang/test/OpenMP/target_messages.cpp

4 ↗

(On Diff #231582)

The clean-up is not strictly necessary. I came across this file when I was looking for the right file to add the tests, and thought it would be better to group similar tests (and their corresponding CHECK patterns) together.

[ABataev]

clang/test/OpenMP/openmp_offload_registration.cpp

3–5

Do not add tests targets other than aarch64

clang/test/OpenMP/target_messages.cpp

4 ↗

(On Diff #231582)

Do not do this in this patch, these changes are not related to the patch itself.

[bryanpkc]

clang/test/OpenMP/openmp_offload_registration.cpp

3–5

OK, thank you.

clang/test/OpenMP/target_messages.cpp

4 ↗

(On Diff #231582)

OK, I will remove these changes.

[bryanpkc]

Removed unrelated changes from this patch.

[ABataev]

LG

clang/lib/Frontend/CompilerInvocation.cpp

#include "clang/Basic/LangStandards.def"
 
   // Get the OpenMP target triples if any.
   if (Arg *A = Args.getLastArg(options::OPT_fopenmp_targets_EQ)) {
 
     for (unsigned i = 0; i < A->getNumValues(); ++i) {
       llvm::Triple TT(A->getValue(i));
 
       if (TT.getArch() == llvm::Triple::UnknownArch ||
-          !(TT.getArch() == llvm::Triple::ppc ||
+          !(TT.getArch() == llvm::Triple::aarch64 ||
+            TT.getArch() == llvm::Triple::ppc ||
             TT.getArch() == llvm::Triple::ppc64 ||
             TT.getArch() == llvm::Triple::ppc64le ||
             TT.getArch() == llvm::Triple::nvptx ||
             TT.getArch() == llvm::Triple::nvptx64 ||
             TT.getArch() == llvm::Triple::x86 ||
             TT.getArch() == llvm::Triple::x86_64))
         Diags.Report(diag::err_drv_invalid_omp_target) << A->getValue(i);
       else

clang/test/OpenMP/openmp_offload_registration.cpp

-// Test for offload registration code for two targets
+// Test offload registration for two targets, and test offload target validation.
 // RUN: %clang_cc1 -verify -fopenmp -x c -triple x86_64-unknown-linux-gnu -fopenmp-targets=x86_64-pc-linux-gnu,powerpc64le-ibm-linux-gnu -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang_cc1 -verify -fopenmp -x c -triple x86_64-unknown-linux-gnu -fopenmp-targets=aarch64-unknown-linux-gnu -emit-llvm %s -o - | FileCheck %s
 // expected-no-diagnostics
 
 void foo() {
 #pragma omp target
   {}
 }
 
 // CHECK-DAG: [[ENTTY:%.+]] = type { i8*, i8*, i[[SZ:32|64]], i32, i32 }
 
 // Check target registration is registered as a Ctor.