Dump cache key on clang cache misses

Author: cachemeifyoucan

Sources/SWBTaskExecution/TaskActions/ClangCompileTaskAction.swift

@@ -16,6 +16,7 @@ public import SWBCore
 public import SWBLLBuild
 import Foundation
 import SWBProtocol
+import TSCBasic
 
 public final class ClangCompileTaskAction: TaskAction, BuildValueValidatingTaskAction {
     public override class var toolIdentifier: String {
@@ -273,7 +274,8 @@ public final class ClangCompileTaskAction: TaskAction, BuildValueValidatingTaskA
                         casDBs: casDBs,
                         workingDirectory: task.workingDirectory,
                         outputDelegate: outputDelegate,
-                        enableDiagnosticRemarks: explicitModulesPayload.casOptions!.enableDiagnosticRemarks
+                        enableDiagnosticRemarks: explicitModulesPayload.casOptions!.enableDiagnosticRemarks,
+                        casPath: explicitModulesPayload.casOptions!.casPath.str
                     ) {
                         lastResult = .succeeded
                         continue
@@ -404,7 +406,8 @@ public final class ClangCompileTaskAction: TaskAction, BuildValueValidatingTaskA
         casDBs: ClangCASDatabases,
         workingDirectory: Path,
         outputDelegate: any TaskOutputDelegate,
-        enableDiagnosticRemarks: Bool
+        enableDiagnosticRemarks: Bool,
+        casPath: String
     ) throws -> Bool {
         guard let cacheKey = command.cacheKey else {
             throw StubError.error("missing cache key")
@@ -413,6 +416,12 @@ public final class ClangCompileTaskAction: TaskAction, BuildValueValidatingTaskA
             if enableDiagnosticRemarks {
                 outputDelegate.note("cache miss: \(cacheKey)")
             }
+            let clangCASTool = Path(command.arguments[0]).dirname.join("clang-cas-test")
+            let command: [String] = [clangCASTool.str, "--cas", casPath, "--print-compile-job-cache-key", cacheKey]
+            let process = TSCBasic.Process(arguments: command)
+            try process.launch()
+            let result = try process.waitUntilExit()
+            try outputDelegate.note(result.utf8Output())
             outputDelegate.incrementCounter(.clangCacheMisses)
             outputDelegate.incrementTaskCounter(.cacheMisses)
             outputDelegate.emitOutput("Cache miss\n")

Sources/SWBTaskExecution/TaskActions/PrecompileClangModuleTaskAction.swift

@@ -190,7 +190,8 @@ final public class PrecompileClangModuleTaskAction: TaskAction, BuildValueValida
                     casDBs: casDBs,
                     workingDirectory: dependencyInfo.workingDirectory,
                     outputDelegate: outputDelegate,
-                    enableDiagnosticRemarks: key.casOptions!.enableDiagnosticRemarks
+                    enableDiagnosticRemarks: key.casOptions!.enableDiagnosticRemarks,
+                    casPath: key.casOptions!.casPath.str
                 ) {
                     return .succeeded
                 }