chore: Use rust-lld as linker to speed up test execution in CI as well as locally

.github/workflows/docs.yml

@@ -64,6 +64,21 @@ jobs:
         uses: actions-rust-lang/setup-rust-toolchain@v1.8.0
         with:
           cache-workspaces: "./libs -> ./target"
+          components: llvm-tools-preview
+      - name: Install linker (Windows)
+        if: ${{ matrix.os == 'windows-2022' }}
+        uses: taiki-e/install-action@v2
+        with:
+          tool: cargo-binutils
+      - name: Install linker (Linux)
+        if: ${{ matrix.os == 'ubuntu-22.04' }}
+        run: |
+          sudo apt-get update
+          sudo apt-get install lld clang
+      - name: Install linker (MacOS)
+        if: ${{ matrix.os == 'macos-12' || matrix.os == 'macos-14' }}
+        run: |
+          brew install llvm
       - name: Build CLI
         run: |
           cd libs
@@ -215,9 +230,23 @@ jobs:
       - name: Install Rust stable toolchain
         uses: actions-rust-lang/setup-rust-toolchain@v1.8.0
         with:
-          components: rustfmt
+          components: rustfmt, llvm-tools-preview
           rustflags: ""
           cache-workspaces: "./libs -> ./target"
+      - name: Install linker (Windows)
+        if: ${{ matrix.os == 'windows-2022' }}
+        uses: taiki-e/install-action@v2
+        with:
+          tool: cargo-binutils
+      - name: Install linker (Linux)
+        if: ${{ matrix.os == 'ubuntu-22.04' }}
+        run: |
+          sudo apt-get update
+          sudo apt-get install lld clang
+      - name: Install linker (MacOS)
+        if: ${{ matrix.os == 'macos-12' || matrix.os == 'macos-14' }}
+        run: |
+          brew install llvm
       - name: Download pavex CLI artifact
         uses: actions/download-artifact@v4
         with:

.gitignore

@@ -1,7 +1,6 @@
 /libs/ui_test_envs
 /libs/target
 /libs/vendor
-/libs/.cargo
 /doc_examples/tutorial_envs/
 /doc_examples/**/target
 /examples/**/vendor
@@ -14,4 +13,4 @@
 trace-*.json
 /.cache/
 /docs/api_reference/
-.direnv/
+.direnv/

libs/.cargo/config.toml

@@ -0,0 +1,20 @@
+# On Windows
+# ```
+# cargo install -f cargo-binutils
+# rustup component add llvm-tools-preview
+[target.x86_64-pc-windows-msvc]
+rustflags = ["-C", "link-arg=-fuse-ld=lld"]
+[target.x86_64-pc-windows-gnu]
+rustflags = ["-C", "link-arg=-fuse-ld=lld"]
+
+# On Linux:
+# - Ubuntu, `sudo apt-get install lld clang`
+# - Arch, `sudo pacman -S lld clang`
+[target.x86_64-unknown-linux-gnu]
+rustflags = ["-C", "linker=clang", "-C", "link-arg=-fuse-ld=lld"]
+
+# On MacOS, `brew install llvm` and follow steps in `brew info llvm`
+[target.x86_64-apple-darwin]
+rustflags = ["-C", "link-arg=-fuse-ld=lld"]
+[target.aarch64-apple-darwin]
+linker = "/opt/homebrew/opt/llvm/bin/ld64.lld"

libs/pavex_test_runner/src/lib.rs

@@ -400,9 +400,17 @@ impl TestData {
         let mut cargo_config = toml! {
             [build]
             incremental = false
-
-            [registries.crates-io]
-            protocol = "sparse"
+
+            [target.x86_64-pc-windows-msvc]
+            linker = "rust-lld"
+            [target.x86_64-pc-windows-gnu]
+            linker = "rust-lld"
+            [target.x86_64-unknown-linux-gnu]
+            linker = "rust-lld"
+            [target.x86_64-apple-darwin]
+            linker = "rust-lld"
+            [target.aarch64-apple-darwin]
+            linker = "rust-lld"
         };
         cargo_config["build"]
             .as_table_mut()