Update and extend clang20 (#203)

* Provide `clang20` toolchains for `graviton2` and `graviton3`

Author: martin4861

.github/workflows/ci.yaml

@@ -23,7 +23,7 @@ jobs:
 
       - name: Run format
         run: |
-          bazel run //:buildifier
+          bazel run //tools/buildifier:buildifier
           git diff --exit-code
 
   example-small-world:
@@ -47,5 +47,6 @@ jobs:
 
       - name: Run format
         run: |
-          bazel run //:buildifier
+          cd examples/small_world
+          bazel run //tools/buildifier:buildifier
           git diff --exit-code

BUILD.bazel

@@ -1,5 +0,0 @@
-load("@buildifier_prebuilt//:rules.bzl", "buildifier")
-
-buildifier(
-    name = "buildifier",
-)

MODULE.bazel

@@ -10,16 +10,16 @@
 
 module(
     name = "rules_swiftnav",
-    version = "0.10.0",
+    version = "0.11.0",
     compatibility_level = 1,
 )
 
 # Core Bazel dependencies
-bazel_dep(name = "bazel_skylib", version = "1.7.1")
-bazel_dep(name = "platforms", version = "0.0.11")
-bazel_dep(name = "rules_cc", version = "0.1.1")
-bazel_dep(name = "rules_pkg", version = "1.0.1")
-bazel_dep(name = "rules_oci", version = "1.0.0")
+bazel_dep(name = "bazel_skylib", version = "1.8.2")
+bazel_dep(name = "platforms", version = "1.0.0")
+bazel_dep(name = "rules_cc", version = "0.2.14")
+bazel_dep(name = "rules_pkg", version = "1.1.0")
+bazel_dep(name = "rules_oci", version = "1.8.0")
 
 # Register module extensions
 swift_cc_toolchain_ext = use_extension("@rules_swiftnav//cc:extensions.bzl", "swift_cc_toolchain_extension")

MODULE.bazel.lock

@@ -115,7 +115,7 @@ cc_toolchain_config(
         "//conditions:default": [],
     }),
     host_system_name = X86_64_LINUX,
-    target_cpu = "k8",
+    target_cpu = "k8",  # this should be aarch64?
     target_libc = "glibc_unknown",
     target_system_name = AARCH64_LINUX,
     tool_paths = {
@@ -125,7 +125,7 @@ cc_toolchain_config(
         "gcov": "wrappers/llvm-profdata",
         "llvm-cov": "wrappers/llvm-cov",
         "llvm-profdata": "wrappers/llvm-profdata",
-        "ld": "wrappers/ld.ldd",
+        "ld": "wrappers/ld.ldd",  # This should be ld.lld?
         "nm": "wrappers/llvm-nm",
         "objcopy": "wrappers/llvm-objcopy",
         "objdump": "wrappers/llvm-objdump",

cc/toolchains/llvm/x86_64-aarch64-linux/BUILD.bazel

@@ -102,13 +102,18 @@ cc_toolchain_config(
     abi_libc_version = "glibc_unknown",
     abi_version = "clang",
     builtin_sysroot = select({
-        # _use_libcpp case needs to be implemented properly here!
+        "@rules_swiftnav//cc:_use_libcpp": None,
         "//conditions:default": "external/rules_swiftnav++swift_cc_toolchain_extension+aarch64-sysroot",
     }),
     compiler = "clang",
     cxx_builtin_include_directories = [
         "%sysroot%/usr/include",
     ],
+    extra_copts = select({
+        "@rules_swiftnav//cc/constraints:graviton2": ["-mcpu=neoverse-n1"],
+        "@rules_swiftnav//cc/constraints:graviton3": ["-mcpu=neoverse-512tvb"],
+        "//conditions:default": [],
+    }),
     host_system_name = X86_64_LINUX,
     target_cpu = "aarch64",
     target_libc = "glibc_unknown",
@@ -158,3 +163,39 @@ toolchain(
     toolchain = ":cc-clang-x86_64-aarch64-linux",
     toolchain_type = "@bazel_tools//tools/cpp:toolchain_type",
 )
+
+toolchain(
+    name = "cc-toolchain-aarch64-bullseye-graviton2",
+    exec_compatible_with = [
+        "@platforms//cpu:x86_64",
+        "@platforms//os:linux",
+    ],
+    target_compatible_with = [
+        "@platforms//os:linux",
+        "@platforms//cpu:aarch64",
+        "@rules_swiftnav//cc/constraints:glibc_2_31",
+        "@rules_swiftnav//cc/constraints:graviton2",
+        "@rules_swiftnav//cc/constraints:llvm20_toolchain",
+    ],
+    target_settings = None,
+    toolchain = ":cc-clang-x86_64-aarch64-linux",
+    toolchain_type = "@bazel_tools//tools/cpp:toolchain_type",
+)
+
+toolchain(
+    name = "cc-toolchain-aarch64-bullseye-graviton3",
+    exec_compatible_with = [
+        "@platforms//cpu:x86_64",
+        "@platforms//os:linux",
+    ],
+    target_compatible_with = [
+        "@platforms//os:linux",
+        "@platforms//cpu:aarch64",
+        "@rules_swiftnav//cc/constraints:glibc_2_31",
+        "@rules_swiftnav//cc/constraints:graviton3",
+        "@rules_swiftnav//cc/constraints:llvm20_toolchain",
+    ],
+    target_settings = None,
+    toolchain = ":cc-clang-x86_64-aarch64-linux",
+    toolchain_type = "@bazel_tools//tools/cpp:toolchain_type",
+)

cc/toolchains/llvm20/x86_64-aarch64-linux/BUILD.bazel

@@ -1,5 +0,0 @@
-load("@buildifier_prebuilt//:rules.bzl", "buildifier")
-
-buildifier(
-    name = "buildifier",
-)

examples/small_world/BUILD.bazel

@@ -1,6 +1,6 @@
 module(name = "small_world")
 
-bazel_dep(name = "platforms", version = "0.0.11")
+bazel_dep(name = "platforms", version = "1.0.0")
 bazel_dep(name = "rules_swiftnav")
 local_path_override(
     module_name = "rules_swiftnav",