try using a hermetic LLVM toolchain

Author: j2kun

MODULE.bazel

@@ -1,20 +1,12 @@
 module(name = "heir")
 
 bazel_dep(name = "bazel_skylib", version = "1.9.0")
+bazel_dep(name = "rules_cc", version = "0.2.18")
 
-# This must come before apple_support cf. https://github.com/bazelbuild/bazel/issues/25728
-bazel_dep(name = "rules_cc", version = "0.2.13")
+# hermetic LLVM toolchain (for C++ compiler and linker)
+bazel_dep(name = "llvm", version = "0.7.8")
 
-# Apple compilation support.
-# Note this requires full xcode, not just commandline tools
-#
-# Tested with:
-#
-# $ /usr/bin/xcodebuild -version
-#   Xcode 16.2
-#   Build version 16C5032a
-bazel_dep(name = "apple_support", version = "1.24.1", repo_name = "build_bazel_apple_support")
-bazel_dep(name = "rules_apple", version = "3.20.1")
+register_toolchains("@llvm//:all")
 
 # Gazelle puglin for BUILD file autogeneration
 bazel_dep(name = "gazelle", version = "0.47.0")
@@ -24,9 +16,9 @@ bazel_dep(name = "bazel_skylib_gazelle_plugin", version = "1.8.2", dev_dependenc
 # provides the `license` rule, which is required because llvm's gentbl_rule
 # implicitly depends upon the target '//:license'. How bizarre.
 bazel_dep(name = "rules_license", version = "1.0.0")
-bazel_dep(name = "platforms", version = "1.0.0")
+bazel_dep(name = "platforms", version = "1.1.0")
 bazel_dep(name = "rules_go", version = "0.53.0")
-bazel_dep(name = "rules_python", version = "1.5.1")
+bazel_dep(name = "rules_python", version = "1.7.0")
 bazel_dep(name = "googletest", version = "1.17.0")
 bazel_dep(name = "fuzztest", version = "20250805.0")
 bazel_dep(name = "google_benchmark", version = "1.9.1")
@@ -38,22 +30,21 @@ bazel_dep(name = "re2", version = "2025-08-12")
 bazel_dep(name = "isl", version = "0.27")
 bazel_dep(name = "pocketfft", version = "0.0.2")
 bazel_dep(name = "openfhe", version = "1.4.2.bcr.1")
-bazel_dep(name = "abc", version = "0.0.0-20250903-yosyshq.bcr.1")
+bazel_dep(name = "abc", version = "0.64-yosyshq.bcr.1")
 bazel_dep(name = "yosys", version = "0.57.bcr.2")
 
-# Yosys pulls in bison@3.8.2 from BCR, but its hand-rolled config breaks with newer macOS SDK versions.
-# Therefore, we pull in this updated BCR version which uses @rules_cc_autoconf instead of the hand-rolled config.
-single_version_override(
-    module_name = "bison",
-    version = "3.8.2.bcr.2",
-)
+# yosys deps needing newer versions for bazel compatibility
+bazel_dep(name = "bison", version = "3.8.2.bcr.5")
+bazel_dep(name = "m4", version = "1.4.21.bcr.1")
+bazel_dep(name = "libffi", version = "3.4.7.bcr.4")
 
-# Yosys also pulls in libffi@3.4.7.bcr.3, but that version does not work on aarch64 linux.
-# Therefore, we pull in this updated BCR version which specifically adds support for aarch64 linux.
-single_version_override(
-    module_name = "libffi",
-    version = "3.4.7.bcr.4",
-)
+# Clang 21 compatibility
+# Cf. https://github.com/bazelbuild/bazel-central-registry/pull/7989
+bazel_dep(name = "gawk", version = "5.3.2.bcr.7")
+
+# Clang 21 compatibility
+# Cf. https://github.com/bazelbuild/bazel-central-registry/pull/7915
+bazel_dep(name = "sed", version = "4.9.bcr.5")
 
 # LLVM dependency uses module extensions because none of these are in the BCR
 llvm_extensions = use_extension("//bazel:extensions.bzl", "llvm_deps")