Enable Roslyn compiler caching on Windows

eng/pipelines/coreclr/templates/build-cache-stats.yml

@@ -0,0 +1,75 @@
+parameters:
+  archType: 'x64'
+  osGroup: 'linux'
+  buildConfig: ''
+  runtimeFlavor: ''
+  runtimeVariant: ''
+  helixQueues: ''
+  targetRid: ''
+  nameSuffix: ''
+  platform: ''
+  shouldContinueOnError: false
+  osSubgroup: ''
+
+steps:
+  # Roslyn compiler cache
+  - ${{ if or(eq(parameters.osGroup, 'windows'), and(or(eq(parameters.osGroup, 'linux'), eq(parameters.osGroup, 'freebsd'), eq(parameters.osGroup, 'openbsd'), eq(parameters.osGroup, 'osx')), or(eq(parameters.archType, 'x64'), eq(parameters.archType, 'arm64')))) }}:
+    - ${{ if ne(parameters.osGroup, 'windows') }}:
+      - script: |
+          set -euo pipefail
+
+          dotnet="$(Build.SourcesDirectory)/.dotnet/dotnet"
+          if [[ -z "${ROSLYN_CACHE_PATH:-}" ||
+                -z "${ROSLYN_CACHE_BUILD_START:-}" ||
+                ! -x "$dotnet" ]]; then
+              echo "Roslyn compiler cache statistics are unavailable."
+              exit 0
+          fi
+
+          sdkVersion="$("$dotnet" --version)"
+          compilerServer="$(Build.SourcesDirectory)/.dotnet/sdk/$sdkVersion/Roslyn/bincore/VBCSCompiler.dll"
+          if [[ ! -f "$compilerServer" ]]; then
+              echo "Roslyn compiler server not found at $compilerServer."
+              exit 0
+          fi
+
+          "$dotnet" "$compilerServer" \
+            "-cachestats:${ROSLYN_CACHE_BUILD_START}" \
+            "-cachepath:${ROSLYN_CACHE_PATH}" || true
+        displayName: Roslyn compiler cache stats
+        condition: always()
+
+    - ${{ if eq(parameters.osGroup, 'windows') }}:
+      - pwsh: |
+          $dotnet = Join-Path "$(Build.SourcesDirectory)" ".dotnet\dotnet.exe"
+          if ([string]::IsNullOrEmpty($env:ROSLYN_CACHE_PATH) -or
+              [string]::IsNullOrEmpty($env:ROSLYN_CACHE_BUILD_START) -or
+              -not (Test-Path -PathType Leaf $dotnet)) {
+            Write-Host "Roslyn compiler cache statistics are unavailable."
+            exit 0
+          }
+
+          $sdkVersion = (& $dotnet --version).Trim()
+          $compilerServer = Join-Path "$(Build.SourcesDirectory)" ".dotnet\sdk\$sdkVersion\Roslyn\bincore\VBCSCompiler.dll"
+          if (-not (Test-Path -PathType Leaf $compilerServer)) {
+            Write-Host "Roslyn compiler server not found at $compilerServer."
+            exit 0
+          }
+
+          & $dotnet $compilerServer `
+            "-cachestats:$env:ROSLYN_CACHE_BUILD_START" `
+            "-cachepath:$env:ROSLYN_CACHE_PATH"
+
+          if ($LASTEXITCODE -ne 0) {
+            Write-Warning "Roslyn compiler cache statistics exited with code $LASTEXITCODE."
+          }
+
+          exit 0
+        displayName: Roslyn compiler cache stats
+        condition: always()
+
+  # sccache native compiler cache
+  - ${{ if and(or(eq(parameters.osGroup, 'linux'), eq(parameters.osGroup, 'freebsd'), eq(parameters.osGroup, 'openbsd'), eq(parameters.osGroup, 'osx')), or(eq(parameters.archType, 'x64'), eq(parameters.archType, 'arm64'))) }}:
+    - script: sccache --show-stats || true
+      displayName: Sccache stats
+      condition: always()

eng/pipelines/coreclr/templates/jit-hardware-intrinsics-common.yml

@@ -25,9 +25,9 @@ jobs:
       buildArgs: -s clr+libs -c $(_BuildConfig)
       timeoutInMinutes: 360
       preBuildSteps:
-        - template: /eng/pipelines/coreclr/templates/setup-sccache.yml
+        - template: /eng/pipelines/coreclr/templates/setup-build-caches.yml
       postBuildSteps:
-        - template: /eng/pipelines/coreclr/templates/sccache-stats.yml
+        - template: /eng/pipelines/coreclr/templates/build-cache-stats.yml
         - template: /eng/pipelines/common/templates/runtimes/build-runtime-tests-and-send-to-helix.yml
           parameters:
             creator: dotnet-bot
@@ -56,9 +56,9 @@ jobs:
       buildArgs: -s clr.aot+libs.native+libs.sfx -c $(_BuildConfig)
       timeoutInMinutes: 360
       preBuildSteps:
-        - template: /eng/pipelines/coreclr/templates/setup-sccache.yml
+        - template: /eng/pipelines/coreclr/templates/setup-build-caches.yml
       postBuildSteps:
-        - template: /eng/pipelines/coreclr/templates/sccache-stats.yml
+        - template: /eng/pipelines/coreclr/templates/build-cache-stats.yml
         - template: /eng/pipelines/common/templates/runtimes/build-runtime-tests-and-send-to-helix.yml
           parameters:
             creator: dotnet-bot

eng/pipelines/coreclr/templates/setup-sccache.yml → eng/pipelines/coreclr/templates/setup-build-caches.yml

@@ -16,14 +16,44 @@ parameters:
   sccacheVersion: '0.15.0'
 
 steps:
-  - ${{ if and(or(eq(parameters.osGroup, 'linux'), eq(parameters.osGroup, 'freebsd'), eq(parameters.osGroup, 'openbsd'), eq(parameters.osGroup, 'osx')), or(eq(parameters.archType, 'x64'), eq(parameters.archType, 'arm64'))) }}:
-    - template: /eng/pipelines/coreclr/templates/setup-roslyn-cache.yml
-      parameters:
-        osGroup: ${{ parameters.osGroup }}
-        osSubgroup: ${{ parameters.osSubgroup }}
-        archType: ${{ parameters.archType }}
-        nameSuffix: ${{ parameters.nameSuffix }}
+  # Roslyn compiler cache
+  - ${{ if or(eq(parameters.osGroup, 'windows'), and(or(eq(parameters.osGroup, 'linux'), eq(parameters.osGroup, 'freebsd'), eq(parameters.osGroup, 'openbsd'), eq(parameters.osGroup, 'osx')), or(eq(parameters.archType, 'x64'), eq(parameters.archType, 'arm64')))) }}:
+    # Cache entries restored by pull request builds come only from the pull
+    # request itself or its target branch. This lets rolling builds seed the
+    # cache without allowing pull requests to modify caches used by main.
+    #
+    # Keep Debug and Release entries separate so rolling builds can seed both
+    # configurations without competing for the same immutable cache key.
+    # Roslyn's own deterministic key accounts for legs that override the
+    # matrix configuration in their build arguments.
+    - task: Cache@2
+      displayName: Roslyn compiler cache
+      continueOnError: true
+      inputs:
+        key: roslyn | v2 | ${{ parameters.osGroup }}${{ parameters.osSubgroup }} | ${{ parameters.archType }} | ${{ parameters.nameSuffix }} | "$(buildConfigUpper)" | "$(Build.BuildId)"
+        path: $(Pipeline.Workspace)/.roslyn-cache
+        restoreKeys: |
+          roslyn | v2 | ${{ parameters.osGroup }}${{ parameters.osSubgroup }} | ${{ parameters.archType }} | ${{ parameters.nameSuffix }} | "$(buildConfigUpper)"
+          roslyn | v1 | ${{ parameters.osGroup }}${{ parameters.osSubgroup }} | ${{ parameters.archType }} | ${{ parameters.nameSuffix }}
+
+    - ${{ if ne(parameters.osGroup, 'windows') }}:
+      - script: |
+          set -euo pipefail
+          echo "##vso[task.setvariable variable=ROSLYN_CACHE_PATH]$(Pipeline.Workspace)/.roslyn-cache"
+          echo "##vso[task.setvariable variable=ROSLYN_CACHE_BUILD_START]$(date -u +"%Y-%m-%dT%H:%M:%SZ")"
+        displayName: Configure Roslyn compiler cache
+
+    - ${{ if eq(parameters.osGroup, 'windows') }}:
+      - pwsh: |
+          $cachePath = Join-Path "$(Pipeline.Workspace)" ".roslyn-cache"
+          $buildStart = [DateTime]::UtcNow.ToString("yyyy-MM-ddTHH:mm:ssZ")
 
+          Write-Host "##vso[task.setvariable variable=ROSLYN_CACHE_PATH]$cachePath"
+          Write-Host "##vso[task.setvariable variable=ROSLYN_CACHE_BUILD_START]$buildStart"
+        displayName: Configure Roslyn compiler cache
+
+  # sccache native compiler cache
+  - ${{ if and(or(eq(parameters.osGroup, 'linux'), eq(parameters.osGroup, 'freebsd'), eq(parameters.osGroup, 'openbsd'), eq(parameters.osGroup, 'osx')), or(eq(parameters.archType, 'x64'), eq(parameters.archType, 'arm64'))) }}:
     # Set up the Azure Pipeline Cache for sccache's local cache directory.
     # Use a rolling key so each build can update the cache; restoreKeys
     # falls back to the most recent saved entry.
@@ -32,7 +62,7 @@ steps:
     # the *managed* Configuration (Debug for PRs, Release for rolling
     # builds), but sccache only caches native (C/C++) compilations whose
     # flags are controlled by RuntimeConfiguration (-rc), which is
-    # constant per leg regardless of buildConfig.  Omitting it lets PR
+    # constant per leg regardless of buildConfig. Omitting it lets PR
     # builds warm-start from rolling-build caches saved in the main scope.
     #
     # osGroup/osSubgroup/archType keep each platform's cache isolated so

eng/pipelines/global-build.yml

@@ -135,9 +135,9 @@ extends:
             buildArgs: -subset clr.native+libs.native+host.native -c $(_BuildConfig)
             timeoutInMinutes: 120
             preBuildSteps:
-              - template: /eng/pipelines/coreclr/templates/setup-sccache.yml
+              - template: /eng/pipelines/coreclr/templates/setup-build-caches.yml
             postBuildSteps:
-              - template: /eng/pipelines/coreclr/templates/sccache-stats.yml
+              - template: /eng/pipelines/coreclr/templates/build-cache-stats.yml
             condition:
               or(
                 eq(stageDependencies.EvaluatePaths.evaluate_paths.outputs['SetPathVars_non_mono_and_wasm.containsChange'], true),