Enable sccache for macOS CoreCLR legs

eng/native/build-commons.sh

@@ -60,6 +60,18 @@ build_native()
     cmakeArgs="$6"
     message="$7"
 
+    # When sccache is enabled, use it as the compiler launcher.
+    # On macOS, CMake wraps PCH includes with -Xarch_<arch> which sccache
+    # cannot parse.  Use a thin wrapper that strips -Xarch_<arch> flags
+    # (safe in single-architecture builds) before forwarding to sccache.
+    if [[ "${USE_SCCACHE:-}" == "true" ]]; then
+        local __sccacheLauncher="sccache"
+        if [[ "$targetOS" == osx || "$targetOS" == maccatalyst ]]; then
+            __sccacheLauncher="$__RepoRootDir/eng/native/sccache-xarch-wrapper.sh"
+        fi
+        cmakeArgs="-DCMAKE_C_COMPILER_LAUNCHER=$__sccacheLauncher -DCMAKE_CXX_COMPILER_LAUNCHER=$__sccacheLauncher $cmakeArgs"
+    fi
+
     # All set to commence the build
     echo "Commencing build of \"$target\" target in \"$message\" for $__TargetOS.$__TargetArch.$__BuildType in $intermediatesDir"
 

eng/native/sccache-xarch-wrapper.sh

@@ -0,0 +1,37 @@
+#!/usr/bin/env bash
+# Wrapper around sccache for macOS builds.
+# sccache cannot parse -Xarch_<arch> flags that CMake generates for PCH
+# includes. Rewrite them to explicit Clang frontend options that preserve
+# use of the generated PCH while remaining parseable by sccache.
+
+for arg in "$@"; do
+    if [[ "$arg" == "-emit-pch" ]]; then
+        exec "$@"
+    fi
+done
+
+args=()
+skip_xarch=false
+
+for arg in "$@"; do
+    if $skip_xarch; then
+        skip_xarch=false
+        if [[ "$arg" == -include?* ]]; then
+            local_path="${arg#-include}"
+            args+=(
+                "-Xclang" "-include-pch" "-Xclang" "${local_path}.pch"
+                "-Xclang" "-include" "-Xclang" "$local_path"
+            )
+        else
+            args+=("$arg")
+        fi
+        continue
+    fi
+    if [[ "$arg" == -Xarch_* ]]; then
+        skip_xarch=true
+        continue
+    fi
+    args+=("$arg")
+done
+
+exec sccache "${args[@]}"

eng/pipelines/coreclr/templates/sccache-stats.yml

@@ -12,7 +12,7 @@ parameters:
   osSubgroup: ''
 
 steps:
-  - ${{ if and(or(eq(parameters.osGroup, 'linux'), eq(parameters.osGroup, 'freebsd'), eq(parameters.osGroup, 'openbsd')), or(eq(parameters.archType, 'x64'), eq(parameters.archType, 'arm64'))) }}:
+  - ${{ 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/setup-sccache.yml

@@ -11,11 +11,12 @@ parameters:
   shouldContinueOnError: false
   osSubgroup: ''
 
-  # sccache NuGet package version
+  # sccache version. Keep the version in sync across platforms so all jobs
+  # cache against the same compiler-launcher behavior.
   sccacheVersion: '0.15.0'
 
 steps:
-  - ${{ if and(or(eq(parameters.osGroup, 'linux'), eq(parameters.osGroup, 'freebsd'), eq(parameters.osGroup, 'openbsd')), or(eq(parameters.archType, 'x64'), eq(parameters.archType, 'arm64'))) }}:
+  - ${{ 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.
@@ -26,6 +27,10 @@ steps:
     # flags are controlled by RuntimeConfiguration (-rc), which is
     # 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
+    # Mac jobs don't poison the Linux entries (different compiler, different
+    # cache contents).
     - task: Cache@2
       displayName: Sccache cache
       continueOnError: true
@@ -35,11 +40,34 @@ steps:
         restoreKeys: |
           sccache | ${{ parameters.osGroup }}${{ parameters.osSubgroup }} | ${{ parameters.archType }} | ${{ parameters.nameSuffix }}
 
-    # Download the sccache NuGet package and configure the environment.
+    # Download sccache and configure the environment.
+    #
+    # The unsuffixed package contains the linux-musl-x64 binary. On macOS,
+    # select the package matching the agent host architecture.
     - script: |
+        set -euo pipefail
         sccacheVersion="${{ parameters.sccacheVersion }}"
-        sccacheDir="$(Build.SourcesDirectory)/.packages/sccache/${sccacheVersion}/tools"
-        "$(Build.SourcesDirectory)/eng/common/dotnet.sh" package download "sccache@${sccacheVersion}" -o "$(Build.SourcesDirectory)/.packages" -v quiet
+        osGroup="${{ parameters.osGroup }}"
+        sccachePackage="sccache"
+
+        if [[ "$osGroup" == "osx" ]]; then
+            case "$(uname -m)" in
+                arm64)
+                    sccachePackage="sccache.osx-arm64"
+                    ;;
+                x86_64)
+                    sccachePackage="sccache.osx-x64"
+                    ;;
+                *)
+                    echo "Unsupported macOS host architecture: $(uname -m)" >&2
+                    exit 1
+                    ;;
+            esac
+        fi
+
+        "$(Build.SourcesDirectory)/eng/common/dotnet.sh" package download "${sccachePackage}@${sccacheVersion}" -o "$(Build.SourcesDirectory)/.packages" -v quiet
+        sccacheDir="$(Build.SourcesDirectory)/.packages/${sccachePackage}/${sccacheVersion}/tools"
+
         chmod +x "$sccacheDir/sccache"
         echo "##vso[task.prependpath]$sccacheDir"
         echo "##vso[task.setvariable variable=SCCACHE_DIR]$(Pipeline.Workspace)/.sccache"

eng/pipelines/runtime.yml

@@ -404,7 +404,10 @@ extends:
             nameSuffix: CoreCLR_AllSubsets
             buildArgs: -s clr+libs+host+packs -c $(_BuildConfig)
             timeoutInMinutes: 180
+            preBuildSteps:
+              - template: /eng/pipelines/coreclr/templates/setup-sccache.yml
             postBuildSteps:
+              - template: /eng/pipelines/coreclr/templates/sccache-stats.yml
               - template: /eng/pipelines/installer/helix-queues-setup.yml
                 parameters:
                   creator: dotnet-bot
@@ -567,7 +570,10 @@ extends:
             nameSuffix: Libraries_CheckedCoreCLR
             buildArgs: -s clr+libs -c $(_BuildConfig) -rc Checked
             timeoutInMinutes: 120
+            preBuildSteps:
+              - template: /eng/pipelines/coreclr/templates/setup-sccache.yml
             postBuildSteps:
+              - template: /eng/pipelines/coreclr/templates/sccache-stats.yml
               - template: /eng/pipelines/coreclr/templates/build-native-test-assets-step.yml
               - template: /eng/pipelines/common/upload-artifact-step.yml
                 parameters:
@@ -866,7 +872,10 @@ extends:
             timeoutInMinutes: 180
             nameSuffix: NativeAOT
             buildArgs: -s clr.aot+libs+tools.illink -c $(_BuildConfig) -rc $(_BuildConfig) -lc Release /p:RunAnalyzers=false
+            preBuildSteps:
+              - template: /eng/pipelines/coreclr/templates/setup-sccache.yml
             postBuildSteps:
+              - template: /eng/pipelines/coreclr/templates/sccache-stats.yml
               - template: /eng/pipelines/coreclr/nativeaot-post-build-steps.yml
                 parameters:
                   creator: dotnet-bot
@@ -905,8 +914,11 @@ extends:
             nameSuffix: NativeAOT_Libraries
             buildArgs: -s clr.aot+libs+libs.tests -c $(_BuildConfig) /p:TestNativeAot=true /p:RunSmokeTestsOnly=true /p:ArchiveTests=true /p:RunAnalyzers=false
             timeoutInMinutes: 240 # Doesn't actually take long, but we've seen the ARM64 Helix queue often get backlogged for 2+ hours
+            preBuildSteps:
+              - template: /eng/pipelines/coreclr/templates/setup-sccache.yml
             # extra steps, run tests
             postBuildSteps:
+              - template: /eng/pipelines/coreclr/templates/sccache-stats.yml
               - template: /eng/pipelines/libraries/helix.yml
                 parameters:
                   creator: dotnet-bot

src/coreclr/build-runtime.sh

@@ -173,10 +173,6 @@ if [[ "$__TargetArch" != "$__HostArch" ]]; then
     __CMakeArgs="-DCLR_CMAKE_TARGET_ARCH=$__TargetArch $__CMakeArgs"
 fi
 
-if [[ "$USE_SCCACHE" == "true" ]]; then
-    __CMakeArgs="-DCMAKE_C_COMPILER_LAUNCHER=sccache -DCMAKE_CXX_COMPILER_LAUNCHER=sccache $__CMakeArgs"
-fi
-
 eval "$__RepoRootDir/eng/native/version/copy_version_files.sh"
 
 build_native "$__HostOS" "$__HostArch" "$__ProjectRoot" "$__IntermediatesDir" "$__CMakeTarget" "$__CMakeArgs" "CoreCLR component"