[bazel] BLAKE3: Adopt aarch64 and x86_64.

[chapuni]

Summary

FIXME: arm(32) may be applicable here. I haven't tested yet.

[MaskRay]

Looks great!

% cd utils/bazel
% bazel build --config=generic_clang @llvm-project//llvm:Support --copt=-w

I can find sse and avx .o files in bazel-out/k8-fastbuild/bin/external/llvm-project/llvm/libSupport.so-2.params.

utils/bazel/llvm-project-overlay/llvm/BUILD.bazel

205

https://docs.bazel.build/versions/main/configurable-attributes.html#the-default-condition there should be a //conditions:default condition for non-aarch64-nonx86_64 CPUs.

[chapuni]

• Fixup

[chapuni]

utils/bazel/llvm-project-overlay/llvm/BUILD.bazel

205

I misunderstood to expect noop w/o default and I have confirmed default:[] is essential here. Thanks!

utils/bazel/llvm-project-overlay/llvm/BUILD.bazel

]) + select({
             "lib/Support/Unix/*.h",
             "lib/Support/Unix/*.inc",
         ]),
     }) + [
         "lib/Support/BLAKE3/blake3_impl.h",
         "lib/Support/BLAKE3/blake3.c",
         "lib/Support/BLAKE3/blake3_dispatch.c",
         "lib/Support/BLAKE3/blake3_portable.c",
+    ] + select({
+        "@platforms//cpu:aarch64": [
+            "lib/Support/BLAKE3/blake3_neon.c",
+        ],
+        "@platforms//cpu:x86_64": [
+            "lib/Support/BLAKE3/blake3_sse2_x86-64_unix.S",
+            "lib/Support/BLAKE3/blake3_sse41_x86-64_unix.S",
+            "lib/Support/BLAKE3/blake3_avx2_x86-64_unix.S",
+            "lib/Support/BLAKE3/blake3_avx512_x86-64_unix.S",
         ],
+        "//conditions:default": [
+        ]
+    }),
     hdrs = glob([
         "include/llvm/Support/**/*.h",
         "include/llvm/ADT/*.h",
     ]) + [
         "include/llvm-c/Core.h",
         "include/llvm-c/DataTypes.h",
         "include/llvm-c/Deprecated.h",
         "include/llvm-c/DisassemblerTypes.h",
         "include/llvm-c/Error.h",
         "include/llvm-c/ErrorHandling.h",
         "include/llvm-c/ExternC.h",
         "include/llvm-c/Support.h",
         "include/llvm-c/Types.h",
         "include/llvm-c/blake3.h",
         "include/llvm/ExecutionEngine/JITSymbol.h",
         "include/llvm/Support/Extension.def",
         "include/llvm/Support/VCSRevision.h",
     ],
     copts = llvm_copts,
-    defines = [
+    defines = select({
+        "@platforms//cpu:aarch64": [
+        ],
+        "//conditions:default": [
+            "BLAKE3_USE_NEON=0",
+        ]
+    }) + select({
+        "@platforms//cpu:x86_64": [
+        ],
+        "//conditions:default": [
             "BLAKE3_NO_AVX2",
             "BLAKE3_NO_AVX512",
             "BLAKE3_NO_SSE2",
             "BLAKE3_NO_SSE41",
-        "BLAKE3_USE_NEON=0",
-    ],
+        ]
+    }),
     includes = ["include"],
     linkopts = select({
         "@bazel_tools//src/conditions:windows": [],
         "@bazel_tools//src/conditions:freebsd": [
             "-pthread",
             "-lexecinfo",
             "-ldl",
             "-lm",