Bazel: Update to latest rules_cc, rules_swift, and apple_support

Note that `rules_swift` requires the versions of `apple_support` and
`rules_cc` we're updating to.

Also update the Swift version we use in the build to 6.3.3, which
is supported out-of-the-box by the new `rules_swift` version.

Author: jketema

.bazelrc

@@ -11,6 +11,9 @@ build --compilation_mode opt
 common --override_module=semmle_code=%workspace%/misc/bazel/semmle_code_stub
 
 build --repo_env=CC=clang --repo_env=CXX=clang++
+# The standalone Linux toolchain uses gold, which does not support the
+# LLD-specific -z nostart-stop-gc workaround enabled by rules_swift.
+build:linux --features=-swift.lld_gc_workaround
 # Disable Android SDK auto-detection (we don't use it, and rules_android has Bazel 9 compatibility issues)
 build --repo_env=ANDROID_HOME=
 

MODULE.bazel

@@ -15,7 +15,7 @@ local_path_override(
 # see https://registry.bazel.build/ for a list of available packages
 
 bazel_dep(name = "platforms", version = "1.0.0")
-bazel_dep(name = "rules_cc", version = "0.2.17")
+bazel_dep(name = "rules_cc", version = "0.2.20")
 bazel_dep(name = "rules_go", version = "0.60.0")
 bazel_dep(name = "rules_java", version = "9.6.1")
 bazel_dep(name = "rules_pkg", version = "1.2.0")
@@ -31,13 +31,13 @@ bazel_dep(name = "gazelle", version = "0.50.0")
 bazel_dep(name = "rules_dotnet", version = "0.21.5-codeql.1")
 bazel_dep(name = "googletest", version = "1.17.0.bcr.2")
 bazel_dep(name = "rules_rust", version = "0.69.0")
-bazel_dep(name = "rules_swift", version = "4.0.0-rc4")
+bazel_dep(name = "rules_swift", version = "4.0.0-rc5")
 bazel_dep(name = "swift-syntax", version = "603.0.2")
 
 # Needed so we can `use_repo` `local_config_xcode` and
 # `local_config_apple_cc_toolchains` below (referenced by the per-target
 # Xcode-config transition in `unified/swift-syntax-rs/xcode_transition.bzl`).
-bazel_dep(name = "apple_support", version = "2.6.1")
+bazel_dep(name = "apple_support", version = "2.8.0")
 bazel_dep(name = "zstd", version = "1.5.7.bcr.1")
 
 bazel_dep(name = "buildifier_prebuilt", version = "6.4.0", dev_dependency = True)
@@ -238,7 +238,7 @@ use_repo(
 swift = use_extension("@rules_swift//swift:extensions.bzl", "swift")
 swift.toolchain(
     name = "swift_toolchain",
-    swift_version = "6.3.2",
+    swift_version = "6.3.3",
 )
 use_repo(
     swift,

unified/swift-syntax-rs/.swift-version

@@ -1 +1 @@
-6.3.2
+6.3.3

unified/swift-syntax-rs/BUILD.bazel

@@ -2,6 +2,7 @@ load("@rules_cc//cc:defs.bzl", "cc_library")
 load("@rules_rust//rust:defs.bzl", "rust_binary", "rust_library", "rust_test")
 load("//unified:platforms.bzl", "UNIFIED_SUPPORTED_PLATFORMS")
 load(":swift_runtime.bzl", "swift_runtime_libs")
+load(":swift_runtime_linking.bzl", "swift_runtime_linking")
 load(":xcode_transition.bzl", "xcode_transition_swift_library")
 
 package(default_visibility = ["//visibility:public"])
@@ -11,15 +12,23 @@ swift_runtime_libs(
     toolchain = "@swift_toolchain_ubuntu22.04//:files",
 )
 
-# The `$ORIGIN` runpath makes an executable look beside itself instead, so
-# we find the Swift runtime libraries we bundle with the extractor.
+swift_runtime_linking(
+    name = "_swift_runtime_cc_info",
+)
+
+# On Linux, provide the downloaded Swift runtime at link time and look beside
+# the executable for the copies bundled with the extractor at runtime.
 cc_library(
-    name = "swift_runtime_rpath",
+    name = "swift_runtime_linking",
     linkopts = select({
         "@platforms//os:linux": ["-Wl,-rpath,$$ORIGIN"],
         "//conditions:default": [],
     }),
     target_compatible_with = UNIFIED_SUPPORTED_PLATFORMS,
+    deps = select({
+        "@platforms//os:linux": [":_swift_runtime_cc_info"],
+        "//conditions:default": [],
+    }),
 )
 
 # Swift FFI shim: wraps swift-syntax and exposes a small C ABI.
@@ -46,7 +55,7 @@ rust_library(
     edition = "2024",
     target_compatible_with = UNIFIED_SUPPORTED_PLATFORMS,
     deps = [
-        ":swift_runtime_rpath",
+        ":swift_runtime_linking",
         ":swift_syntax_ffi",
     ],
 )

unified/swift-syntax-rs/README.md

@@ -129,7 +129,7 @@ The build does not depend on any particular version manager. You need:
 - **Rust** — pinned to `1.88` by the repo-root [`rust-toolchain.toml`](../../rust-toolchain.toml),
   which `rustup` picks up automatically.
 - **Swift** — pinned to the version in [`.swift-version`](.swift-version)
-  (currently `6.3.2`), used to build `swift-syntax` `603.0.2`. Install it any way
+  (currently `6.3.3`), used to build `swift-syntax` `603.0.2`. Install it any way
   you like — [swift.org](https://www.swift.org/install/) or
   [swiftly](https://www.swift.org/swiftly/) (which reads `.swift-version`), or a
   system package. Just make sure `swift` (and `swiftc`) are on your `PATH` —

unified/swift-syntax-rs/swift_runtime_linking.bzl

@@ -0,0 +1,11 @@
+"""Expose the selected Swift toolchain's dynamic runtime to native dependents."""
+
+load("@rules_swift//swift:swift.bzl", "swift_common")
+
+def _swift_runtime_linking_impl(ctx):
+    return [swift_common.get_toolchain(ctx).dynamic_runtime_cc_info]
+
+swift_runtime_linking = rule(
+    implementation = _swift_runtime_linking_impl,
+    toolchains = swift_common.use_toolchain(),
+)