[CI] Refactor DXC and WARP installation steps to composite actions

This avoids having to duplicate the steps and version numbers across
mutiple workflows.

.github/actions/install-dxc/action.yml

@@ -0,0 +1,17 @@
+name: "Install DXC"
+description: "Install DXC"
+runs:
+  using: "composite"
+  steps:
+    - shell: bash
+      run: |
+        set -e
+
+        export DXC_RELEASE="v1.8.2502"
+        export DXC_FILENAME="dxc_2025_02_20.zip"
+
+        curl.exe -L --retry 5 https://github.com/microsoft/DirectXShaderCompiler/releases/download/$DXC_RELEASE/$DXC_FILENAME -o dxc.zip
+        7z.exe e dxc.zip -odxc bin/x64/{dxc.exe,dxcompiler.dll}
+
+        # We need to use cygpath to convert PWD to a windows path as we're using bash.
+        cygpath --windows "$PWD/dxc" >> "$GITHUB_PATH"

.github/actions/install-warp/action.yml

@@ -0,0 +1,25 @@
+name: "Install WARP"
+description: "Install WARP"
+inputs:
+  target-dirs:
+    description: "Space-separated list of directories into which to install the WARP DLL."
+    required: true
+runs:
+  using: "composite"
+  steps:
+    - shell: bash
+      run: |
+        set -e
+
+        export WARP_VERSION="1.0.13"
+
+        # Make sure dxc is in path.
+        dxc --version
+
+        curl.exe -L --retry 5 https://www.nuget.org/api/v2/package/Microsoft.Direct3D.WARP/$WARP_VERSION -o warp.zip
+        7z.exe e warp.zip -owarp build/native/bin/x64/d3d10warp.dll
+
+        for dir in ${{ inputs.target-dirs }}; do
+          mkdir -p ${{ inputs.target-dirs }}
+          cp -v warp/d3d10warp.dll "$dir"
+        done

.github/workflows/ci.yml

@@ -20,16 +20,8 @@ env:
   # Sourced from https://vulkan.lunarg.com/sdk/home#linux
   VULKAN_SDK_VERSION: "1.4.313"
   VULKAN_FULL_SDK_VERSION: "1.4.313.0"
-  # Sourced from https://www.nuget.org/packages/Microsoft.Direct3D.WARP
-  WARP_VERSION: "1.0.13"
 
-  # Sourced from https://github.com/microsoft/DirectXShaderCompiler/releases
-  #
-  # Must also be changed in shaders.yaml
-  DXC_RELEASE: "v1.8.2502"
-  DXC_FILENAME: "dxc_2025_02_20.zip"
-
-  # These Mesa version definition is duplicated in the install-mesa-action.
+  # These Mesa version definition is duplicated in the install-mesa action.
   MESA_VERSION: "24.3.4"
 
   # This is the MSRV used by `wgpu` itself and all surrounding infrastructure.
@@ -541,32 +533,13 @@ jobs:
 
       - name: (Windows) Install DXC
         if: matrix.os == 'windows-2022'
-        shell: bash
-        run: |
-          set -e
-
-          curl.exe -L --retry 5 https://github.com/microsoft/DirectXShaderCompiler/releases/download/$DXC_RELEASE/$DXC_FILENAME -o dxc.zip
-          7z.exe e dxc.zip -odxc bin/x64/{dxc.exe,dxcompiler.dll}
-
-          # We need to use cygpath to convert PWD to a windows path as we're using bash.
-          cygpath --windows "$PWD/dxc" >> "$GITHUB_PATH"
+        uses: ./.github/actions/install-dxc
 
       - name: (Windows) Install WARP
         if: matrix.os == 'windows-2022'
-        shell: bash
-        run: |
-          set -e
-
-          # Make sure dxc is in path.
-          dxc --version
-
-          curl.exe -L --retry 5 https://www.nuget.org/api/v2/package/Microsoft.Direct3D.WARP/$WARP_VERSION -o warp.zip
-          7z.exe e warp.zip -owarp build/native/bin/x64/d3d10warp.dll
-
-          mkdir -p target/llvm-cov-target/debug/deps
-
-          cp -v warp/d3d10warp.dll target/llvm-cov-target/debug/
-          cp -v warp/d3d10warp.dll target/llvm-cov-target/debug/deps
+        uses: ./.github/actions/install-warp
+        with:
+          target-dirs: "target/llvm-cov-target/debug target/llvm-cov-target/debug/deps"
 
       - name: (Windows) Install Mesa
         if: matrix.os == 'windows-2022'
@@ -627,7 +600,7 @@ jobs:
 
       - name: (Linux) Install Mesa
         if: matrix.os == 'ubuntu-24.04'
-        uses: ./.github/install-mesa-action
+        uses: ./.github/actions/install-mesa
 
       - name: Delete Naga snapshots
         shell: bash

.github/workflows/cts.yml

@@ -65,7 +65,7 @@ jobs:
 
       - name: (Linux) Install Mesa
         if: matrix.os == 'ubuntu-24.04'
-        uses: ./.github/install-mesa-action
+        uses: ./.github/actions/install-mesa
 
       - name: run CTS
         shell: bash

.github/workflows/shaders.yml

@@ -18,12 +18,6 @@ env:
   # We don't include the 4th version number, as it's not used in any URL.
   VULKAN_SDK_VERSION: "1.4.313"
 
-  # Sourced from https://github.com/microsoft/DirectXShaderCompiler/releases
-  #
-  # Must also be changed in ci.yaml
-  DXC_RELEASE: "v1.8.2502"
-  DXC_FILENAME: "dxc_2025_02_20.zip"
-
 jobs:
   naga-validate-windows:
     name: "Validate: HLSL"
@@ -56,15 +50,7 @@ jobs:
         shell: powershell
 
       - name: Setup DXC
-        shell: bash
-        run: |
-          set -e
-
-          curl.exe -L --retry 5 https://github.com/microsoft/DirectXShaderCompiler/releases/download/$DXC_RELEASE/$DXC_FILENAME -o dxc.zip
-          7z.exe e dxc.zip -odxc bin/x64/{dxc.exe,dxcompiler.dll}
-
-          # We need to use cygpath to convert PWD to a windows path as we're using bash.
-          cygpath --windows "$PWD/dxc" >> "$GITHUB_PATH"
+        uses: ./.github/actions/install-dxc
 
       - name: Validate
         shell: bash