Add Bazel build rules

.cargo/config.toml

@@ -1,6 +1,6 @@
 [net]
 git-fetch-with-cli = true
 
-# https://github.com/rust-lang/cargo/issues/3946#issuecomment-973132993
 [env]
-CARGO_WORKSPACE_DIR = { value = "", relative = true }
+# Used in tests/src/dload.rs to dynamically load sidecar_lite.
+LIBSIDECAR_LITE_DIR = { value = "target/debug", relative = true }

.github/workflows/bazel.yml

@@ -0,0 +1,30 @@
+name: Bazel CI
+
+on:
+  push:
+    branches: [ "main" ]
+  pull_request:
+    branches: [ "main" ]
+
+jobs:
+  bazel-build-and-test:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest]
+
+    steps:
+      - uses: actions/checkout@v5
+      - uses: bazel-contrib/setup-bazel@0.15.0
+        with:
+          bazelisk-cache: true
+          disk-cache: ${{ github.workflow }}-${{ matrix.os }}
+          repository-cache: true
+      - if: matrix.os == 'ubuntu-latest'
+        run: |
+          sudo apt-get install -y lld
+          sudo update-alternatives --install /usr/bin/ld ld /usr/bin/ld.lld 100
+      - name: Build with Bazel
+        run: bazel build --test_output=errors //...
+      - name: Test with Bazel
+        run: bazel test --test_output=errors //...

.gitignore

@@ -2,3 +2,5 @@
 *.sw*
 out.rs
 tags
+bazel*
+MODULE.bazel.lock

Cargo.toml

@@ -37,5 +37,9 @@ serde = "1.0"
 serde_tokenstream = "0.2"
 syn = "2.0"
 tempfile = "3.3"
-usdt = "0.5.0"
+usdt = "0.6"
 xfr = { git = "https://github.com/oxidecomputer/xfr" }
+
+# TODO: Remove once https://github.com/oxidecomputer/usdt/pull/486 is released.
+[patch.crates-io]
+usdt = { git = "https://github.com/oxidecomputer/usdt" }

MODULE.bazel

@@ -0,0 +1,24 @@
+module(
+    name = "x4c",
+    # Set to version number for releases, only.
+    version = "HEAD",
+)
+
+bazel_dep(name = "rules_rust", version = "0.67.0")
+
+# Pick Rust toolchain version.
+rust = use_extension("@rules_rust//rust:extensions.bzl", "rust")
+rust.toolchain(
+    edition = "2021",
+    versions = ["1.90.0"],
+)
+use_repo(rust, "rust_toolchains")
+
+# Make all crates declared in Cargo.toml available as @crates//:... to Bazel.
+crate = use_extension("@rules_rust//crate_universe:extensions.bzl", "crate")
+crate.from_cargo(
+    name = "crates",
+    cargo_lockfile = "//:Cargo.lock",
+    manifests = ["//:Cargo.toml"],
+)
+use_repo(crate, "crates")