chore: use toolchains_llvm with clang 18 for cross-compile toolchain

Zig CC had linking errors with -latomic (a seemingly recurrent issue with zig), which is required by the new V8 version. Instead, llvm can be used.

Signed-off-by: Matt Leon <[email protected]>

Author: leonm1

.bazelrc

@@ -69,15 +69,17 @@ build:gcc --action_env=CXX=g++
 
 # Use Zig C/C++ compiler.
 build:zig-cc --incompatible_enable_cc_toolchain_resolution
-build:zig-cc --extra_toolchains @zig_sdk//:aarch64-linux-gnu.2.28_toolchain
-build:zig-cc --extra_toolchains @zig_sdk//:x86_64-linux-gnu.2.28_toolchain
+build:zig-cc --action_env BAZEL_DO_NOT_DETECT_CPP_TOOLCHAIN=1
+build:zig-cc --extra_toolchains @llvm_toolchain//:cc-toolchain-x86_64-linux
+build:zig-cc --extra_toolchains @llvm_aarch64//:cc-toolchain-aarch64-linux
+build:zig-cc --extra_toolchains @emsdk//emscripten_toolchain:cc-toolchain-wasm
 build:zig-cc --host_copt=-fno-sanitize=undefined
 
 # Use Zig C/C++ compiler (cross-compile to Linux/aarch64).
 build:zig-cc-linux-aarch64 --config=zig-cc
-build:zig-cc-linux-aarch64 --platforms @zig_sdk//:linux_aarch64_platform
-build:zig-cc-linux-aarch64 --run_under=qemu-aarch64-static
-build:zig-cc-linux-aarch64 --test_env=QEMU_LD_PREFIX=/usr/aarch64-linux-gnu/
+#build:zig-cc-linux-aarch64 --platforms @zig_sdk//platform:linux_arm64
+build:zig-cc-linux-aarch64 --platforms @toolchains_llvm//platforms:linux-aarch64
+build:zig-cc-linux-aarch64 --cxxopt --gcc-install-dir=external/sysroot_linux_arm64/usr/lib/gcc/aarch64-linux-gnu/13/
 
 build --enable_platform_specific_config
 
@@ -86,6 +88,11 @@ build:linux --cxxopt=-std=c++20 --host_cxxopt=-std=c++20
 build:macos --cxxopt=-std=c++20 --host_cxxopt=-std=c++20
 build:windows --cxxopt="/std:c++20" --host_cxxopt="/std:c++20"
 
+# For Zig C/C++ compiler.
+build:linux --sandbox_add_mount_pair=/tmp
+build:macos --sandbox_add_mount_pair=/var/tmp
+build:windows --sandbox_add_mount_pair=C:\Temp
+
 # Enable symlinks and runfiles on Windows (enabled by default on other platforms).
 startup --windows_enable_symlinks
 build:windows --enable_runfiles

bazel/dependencies.bzl

@@ -12,13 +12,15 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-load("@bazel-zig-cc//toolchain:defs.bzl", zig_register_toolchains = "register_toolchains")
 load("@com_google_protobuf//:protobuf_deps.bzl", "protobuf_deps")
+load("@envoy_toolshed//sysroot:sysroot.bzl", "setup_sysroots")
 load("@proxy_wasm_cpp_host//bazel/cargo/wasmsign/remote:crates.bzl", wasmsign_crate_repositories = "crate_repositories")
 load("@proxy_wasm_cpp_host//bazel/cargo/wasmtime/remote:crates.bzl", wasmtime_crate_repositories = "crate_repositories")
 load("@rules_python//python:repositories.bzl", "py_repositories", "python_register_toolchains")
 load("@rules_rust//crate_universe:repositories.bzl", "crate_universe_dependencies")
 load("@rules_rust//rust:repositories.bzl", "rust_repositories", "rust_repository_set")
+load("@toolchains_llvm//toolchain:deps.bzl", "bazel_toolchain_dependencies")
+load("@toolchains_llvm//toolchain:rules.bzl", "llvm_toolchain")
 
 def proxy_wasm_cpp_host_dependencies():
     # Bazel extensions.
@@ -52,14 +54,32 @@ def proxy_wasm_cpp_host_dependencies():
     )
     crate_universe_dependencies(bootstrap = True)
 
-    zig_register_toolchains(
-        version = "0.9.1",
-        url_format = "https://ziglang.org/download/{version}/zig-{host_platform}-{version}.tar.xz",
-        host_platform_sha256 = {
-            "linux-aarch64": "5d99a39cded1870a3fa95d4de4ce68ac2610cca440336cfd252ffdddc2b90e66",
-            "linux-x86_64": "be8da632c1d3273f766b69244d80669fe4f5e27798654681d77c992f17c237d7",
-            "macos-aarch64": "8c473082b4f0f819f1da05de2dbd0c1e891dff7d85d2c12b6ee876887d438287",
-            "macos-x86_64": "2d94984972d67292b55c1eb1c00de46580e9916575d083003546e9a01166754c",
+    setup_sysroots()
+    bazel_toolchain_dependencies()
+    llvm_toolchain(
+        name = "llvm_toolchain",
+        llvm_version = "18.1.8",
+        sha256 = {
+            "linux-x86_64": "54ec30358afcc9fb8aa74307db3046f5187f9fb89fb37064cdde906e062ebf36",
+        },
+        strip_prefix = {
+            "linux-x86_64": "clang+llvm-18.1.8-x86_64-linux-gnu-ubuntu-18.04",
+        },
+        urls = {
+            "linux-x86_64": [
+                "https://github.com/llvm/llvm-project/releases/download/llvmorg-18.1.8/clang+llvm-18.1.8-x86_64-linux-gnu-ubuntu-18.04.tar.xz",
+            ],
+        },
+    )
+
+    llvm_toolchain(
+        name = "llvm_aarch64",
+        llvm_version = "18.1.8",
+        toolchain_roots = {
+            "": "@llvm_toolchain_llvm//",
+        },
+        sysroot = {
+          "linux-aarch64": "@sysroot_linux_arm64//:sysroot",
         },
     )
 

bazel/dependencies_import.bzl

@@ -16,8 +16,11 @@ load("@fuzzing_py_deps//:requirements.bzl", pip_fuzzing_dependencies = "install_
 load("@rules_foreign_cc//foreign_cc:repositories.bzl", "rules_foreign_cc_dependencies")
 load("@rules_fuzzing//fuzzing:repositories.bzl", "rules_fuzzing_dependencies")
 load("@v8_python_deps//:requirements.bzl", pip_v8_dependencies = "install_deps")
+load("@llvm_toolchain//:toolchains.bzl", "llvm_register_toolchains")
 
 def proxy_wasm_cpp_host_dependencies_import():
+    llvm_register_toolchains()
+
     rules_foreign_cc_dependencies()
     rules_fuzzing_dependencies()
 

bazel/repositories.bzl

@@ -60,10 +60,18 @@ def proxy_wasm_cpp_host_repositories():
 
     maybe(
         http_archive,
-        name = "bazel-zig-cc",
-        sha256 = "ff89e0220c72cdc774e451a35e5c3b9f1593d0df71341844b2108c181ac0eef9",
-        strip_prefix = "hermetic_cc_toolchain-0.4.4",
-        url = "https://github.com/uber/hermetic_cc_toolchain/archive/refs/tags/v0.4.4.tar.gz",
+        name = "envoy_toolshed",
+        sha256 = "e2252e46e64417d5cedd9f1eb34a622bce5e13b43837e5fe051c83066b0a400b",
+        strip_prefix = "toolshed-bazel-bins-v0.1.13/bazel",
+        url = "https://github.com/envoyproxy/toolshed/archive/refs/tags/bazel-bins-v0.1.13.tar.gz",
+    )
+    maybe(
+        http_archive,
+        name = "toolchains_llvm",
+        sha256 = "b7cd301ef7b0ece28d20d3e778697a5e3b81828393150bed04838c0c52963a01",
+        strip_prefix = "toolchains_llvm-0.10.3",
+        canonical_id = "v0.10.3",
+        url = "https://github.com/grailbio/bazel-toolchain/releases/download/0.10.3/toolchains_llvm-0.10.3.tar.gz",
     )
 
     maybe(
@@ -191,6 +199,7 @@ def proxy_wasm_cpp_host_repositories():
     maybe(
         http_archive,
         name = "highway",
+        sha256 = "7e0be78b8318e8bdbf6fa545d2ecb4c90f947df03f7aadc42c1967f019e63343",
         urls = [
             "https://github.com/google/highway/archive/refs/tags/1.2.0.tar.gz",
         ],
@@ -200,6 +209,7 @@ def proxy_wasm_cpp_host_repositories():
     maybe(
         http_archive,
         name = "fast_float",
+        sha256 = "d2a08e722f461fe699ba61392cd29e6b23be013d0f56e50c7786d0954bffcb17",
         urls = [
             "https://github.com/fastfloat/fast_float/archive/refs/tags/v7.0.0.tar.gz",
         ],
@@ -231,6 +241,7 @@ def proxy_wasm_cpp_host_repositories():
     maybe(
         http_archive,
         name = "simdutf",
+        sha256 = "512374f8291d3daf102ccd0ad223b1a8318358f7c1295efd4d9a3abbb8e4b6ff",
         urls = [
             "https://github.com/simdutf/simdutf/releases/download/v7.3.0/singleheader.zip",
         ],