[BOLT] Add AArch64 builder and worker

[gkistanova]

LGTM.

When you will do the follow up changes, you may want to remove the clang version number from the name of the builder and from the paths. Using update-alternatives or something similar to manage the versions of the system tool chain might be a good idea. This way you will not need to make changes to zorg every time you update the tool chain.

[Amir]

Address feedback

buildbot/osuosl/master/config/builders.py

'factory' : BOLTBuilder.getBOLTCmakeBuildFactory(
                         "-DLLVM_TARGETS_TO_BUILD=X86;AArch64",
                         "-DBUILD_SHARED_LIBS=ON",
                         "-DLLVM_ENABLE_LLD=ON",
                         "-DBOLT_CLANG_EXE=/usr/bin/clang-12",
                         "-DBOLT_LLD_EXE=/usr/bin/ld.lld-12",
                         ],
                     )},
 
+    {'name': "bolt-aarch64-ubuntu-clang-shared",
+    'tags': ["bolt"],
+    'collapseRequests': True,
+    'workernames':["bolt-worker-aarch64"],
+    'builddir': "bolt-aarch64-ubuntu-clang-shared",
+    'factory' : BOLTBuilder.getBOLTCmakeBuildFactory(
+                    bolttests=True,
+                    extra_configure_args=[
+                        "-DCMAKE_C_COMPILER=clang",
+                        "-DCMAKE_CXX_COMPILER=clang++",
+                        "-DLLVM_APPEND_VC_REV=OFF",
+                        "-DLLVM_CCACHE_BUILD=ON",
+                        "-DLLVM_ENABLE_PROJECTS=bolt",
+                        "-DLLVM_TARGETS_TO_BUILD=AArch64",
+                        "-DBUILD_SHARED_LIBS=ON",
+                        "-DLLVM_ENABLE_LLD=ON",
+                        "-DBOLT_CLANG_EXE=/usr/bin/clang",
+                        "-DBOLT_LLD_EXE=/usr/bin/ld.lld",
+                        ],
+                    )},
+
     # AMD ROCm support.
     {'name' : 'mlir-rocm-mi200',
      'tags'  : ["mlir"],
      'collapseRequests' : False,
      'workernames' : ['mi200-buildbot'],
      'builddir': 'mlir-rocm-mi200',
      'factory' : UnifiedTreeBuilder.getCmakeWithNinjaBuildFactory(
          clean=True,

buildbot/osuosl/master/config/workers.py

return [
 
         # OpenMP on AMDGPU, Ubuntu 18.04.5, Intel(R) Xeon(R) Gold 5218 @ 2.30GHz with 64GB Memory, 1 Vega20 GPU with 16GB Memory
         create_worker("omp-vega20-0", properties={'jobs': 32}, max_builds=1),
         create_worker("omp-vega20-1", properties={'jobs': 32}, max_builds=1),
 
         # AMD ROCm support, Ubuntu 18.04.6, AMD Ryzen @ 1.5 GHz, MI200 GPU
         create_worker("mi200-buildbot", max_builds=1),
 
-        # BOLT worker
+        # BOLT workers
         create_worker("bolt-worker", properties={'jobs' : 16}, max_builds=1),
+        create_worker("bolt-worker-aarch64", properties={'jobs' : 2}, max_builds=1),
 
         # Fedora worker
         create_worker("standalone-build-x86_64", properties={'jobs': 32}, max_builds=1),
         ]