Avoid building the same stuff twice for helix subsets.

Author: adityamandaleeka

.azure/pipelines/ci-public.yml

@@ -553,20 +553,46 @@ stages:
           publishOnError: true
           includeForks: true
 
-    # Helix x64 subset 1
+    # Helix x64 build - shared by both Helix test subsets
     - template: jobs/default-build.yml
       parameters:
-        jobName: Helix_x64_Subset_1
-        jobDisplayName: 'Tests: Helix x64 Subset 1'
+        jobName: Helix_x64_Build
+        jobDisplayName: 'Build: Helix x64'
         agentOs: Windows
-        timeoutInMinutes: 240
+        timeoutInMinutes: 120
         steps:
         # Build the shared framework
         - script: ./eng/build.cmd -ci -prepareMachine -nativeToolsOnMachine -nobl -all -pack -arch x64
                   /p:CrossgenOutput=false /p:ASPNETCORE_TEST_LOG_DIR=artifacts/log $(_InternalRuntimeDownloadArgs)
                   /p:VsTestUseMSBuildOutput=false
           displayName: Build shared fx
-        # -noBuildRepoTasks -noBuildNative -noBuild to avoid repeating work done in the previous step.
+        - task: PublishPipelineArtifact@1
+          displayName: Publish Helix build artifacts
+          inputs:
+            targetPath: $(Build.SourcesDirectory)/artifacts
+            artifactName: Helix_Build_Artifacts
+        artifacts:
+        - name: Helix_Build_Logs_Attempt_$(System.JobAttempt)
+          path: artifacts/log/
+          publishOnError: true
+          includeForks: true
+
+    # Helix x64 subset 1
+    - template: jobs/default-build.yml
+      parameters:
+        jobName: Helix_x64_Subset_1
+        jobDisplayName: 'Tests: Helix x64 Subset 1'
+        agentOs: Windows
+        dependsOn: Helix_x64_Build
+        timeoutInMinutes: 240
+        steps:
+        # Download build artifacts from Helix_x64_Build job
+        - task: DownloadPipelineArtifact@2
+          displayName: Download Helix build artifacts
+          inputs:
+            artifact: Helix_Build_Artifacts
+            path: $(Build.SourcesDirectory)/artifacts
+        # -noBuildRepoTasks -noBuildNative -noBuild to avoid repeating work done in the build job.
         - script: ./eng/build.cmd -ci -prepareMachine -nativeToolsOnMachine -all -noBuildRepoTasks -noBuildNative -noBuild -test
                   -projects eng\helix\helix.proj /p:IsHelixPRCheck=true /p:IsHelixJob=true
                   /p:CrossgenOutput=false /p:ASPNETCORE_TEST_LOG_DIR=artifacts/log $(_InternalRuntimeDownloadArgs)
@@ -588,14 +614,16 @@ stages:
         jobName: Helix_x64_Subset_2
         jobDisplayName: 'Tests: Helix x64 Subset 2'
         agentOs: Windows
+        dependsOn: Helix_x64_Build
         timeoutInMinutes: 240
         steps:
-        # Build the shared framework
-        - script: ./eng/build.cmd -ci -prepareMachine -nativeToolsOnMachine -nobl -all -pack -arch x64
-                  /p:CrossgenOutput=false /p:ASPNETCORE_TEST_LOG_DIR=artifacts/log $(_InternalRuntimeDownloadArgs)
-                  /p:VsTestUseMSBuildOutput=false
-          displayName: Build shared fx
-        # -noBuildRepoTasks -noBuildNative -noBuild to avoid repeating work done in the previous step.
+        # Download build artifacts from Helix_x64_Build job
+        - task: DownloadPipelineArtifact@2
+          displayName: Download Helix build artifacts
+          inputs:
+            artifact: Helix_Build_Artifacts
+            path: $(Build.SourcesDirectory)/artifacts
+        # -noBuildRepoTasks -noBuildNative -noBuild to avoid repeating work done in the build job.
         - script: ./eng/build.cmd -ci -prepareMachine -nativeToolsOnMachine -all -noBuildRepoTasks -noBuildNative -noBuild -test
                   -projects eng\helix\helix.proj /p:IsHelixPRCheck=true /p:IsHelixJob=true
                   /p:CrossgenOutput=false /p:ASPNETCORE_TEST_LOG_DIR=artifacts/log $(_InternalRuntimeDownloadArgs)