ci: add coverage for cts (#7942)

.github/workflows/cts.yml

@@ -43,10 +43,15 @@ jobs:
 
       - name: Install Repo MSRV toolchain
         run: |
-          rustup toolchain install ${{ env.MSRV }} --no-self-update --profile=minimal --target ${{ matrix.target }}
+          rustup toolchain install ${{ env.MSRV }} --no-self-update --profile=minimal --target ${{ matrix.target }} --component llvm-tools
           rustup override set ${{ env.MSRV }}
           cargo -V
 
+      - name: Install `cargo-llvm-cov`
+        uses: taiki-e/install-action@v2
+        with:
+          tool: cargo-llvm-cov
+
       - name: caching
         uses: Swatinem/rust-cache@v2
         with:
@@ -60,7 +65,7 @@ jobs:
           mkdir -p .cargo
           cat <<EOF >> .cargo/config.toml
           [profile.dev]
-          debug = 1
+          debug = "line-tables-only"
           EOF
 
       - name: (Windows) Install DXC
@@ -71,7 +76,7 @@ jobs:
         if: matrix.os == 'windows-2022'
         uses: ./.github/actions/install-warp
         with:
-          target-dirs: "target/debug"
+          target-dirs: "target/llvm-cov-target/debug"
 
       - name: (Linux) Install Mesa
         if: matrix.os == 'ubuntu-24.04'
@@ -79,4 +84,20 @@ jobs:
 
       - name: run CTS
         shell: bash
-        run: cargo xtask cts
+        run: cargo xtask cts --llvm-cov
+
+      - name: Generate coverage report
+        id: coverage
+        shell: bash
+        continue-on-error: true
+        run: |
+          set -e
+
+          cargo llvm-cov report --lcov --output-path lcov.info
+
+      - name: Upload coverage report to Codecov
+        uses: codecov/codecov-action@v5
+        if: steps.coverage.outcome == 'success'
+        with:
+          files: lcov.info
+          token: ${{ secrets.CODECOV_TOKEN }}

xtask/src/cts.rs

@@ -17,6 +17,7 @@ const CTS_DEFAULT_TEST_LIST: &str = "cts_runner/test.lst";
 
 pub fn run_cts(shell: Shell, mut args: Arguments) -> anyhow::Result<()> {
     let skip_checkout = args.contains("--skip-checkout");
+    let llvm_cov = args.contains("--llvm-cov");
 
     let mut list_files = Vec::<OsString>::new();
     while let Some(file) = args.opt_value_from_str("-f")? {
@@ -133,12 +134,18 @@ pub fn run_cts(shell: Shell, mut args: Arguments) -> anyhow::Result<()> {
         log::info!("Skipping CTS checkout because --skip-checkout was specified");
     }
 
+    let run_flags = if llvm_cov {
+        &["llvm-cov", "--no-cfg-coverage", "--no-report", "run"][..]
+    } else {
+        &["run"][..]
+    };
+
     log::info!("Running CTS");
     for test in &tests {
         log::info!("Running {}", test.to_string_lossy());
         shell
             .cmd("cargo")
-            .args(["run"])
+            .args(run_flags)
             .args(["--manifest-path".as_ref(), wgpu_cargo_toml.as_os_str()])
             .args(["-p", "cts_runner"])
             .args(["--bin", "cts_runner"])