From 03ad981dea3f99120bd101f2af0358dd0caaba15 Mon Sep 17 00:00:00 2001
From: cristiangarcia <Cristian.Garcia-Marin@jetbrains.com>
Date: Tue, 24 Oct 2023 09:50:02 +0000
Subject: [PATCH] Make ClangFrontend cacheable

Co-authored-by: Alexander Shabalin <Alexander.Shabalin@jetbrains.com>


Merge-request: KT-MR-11479
Merged-by: Cristian Garcia <Cristian.Garcia-Marin@jetbrains.com>
---
 .../org/jetbrains/kotlin/cpp/ClangFrontend.kt | 59 ++++++++++++-------
 1 file changed, 39 insertions(+), 20 deletions(-)

diff --git a/kotlin-native/build-tools/src/main/kotlin/org/jetbrains/kotlin/cpp/ClangFrontend.kt b/kotlin-native/build-tools/src/main/kotlin/org/jetbrains/kotlin/cpp/ClangFrontend.kt
index 1d5f9858124..37be011ecdc 100644
--- a/kotlin-native/build-tools/src/main/kotlin/org/jetbrains/kotlin/cpp/ClangFrontend.kt
+++ b/kotlin-native/build-tools/src/main/kotlin/org/jetbrains/kotlin/cpp/ClangFrontend.kt
@@ -11,6 +11,7 @@ import org.gradle.api.model.ObjectFactory
 import org.gradle.api.provider.ListProperty
 import org.gradle.api.provider.Property
 import org.gradle.api.provider.Provider
+import org.gradle.api.provider.ProviderFactory
 import org.gradle.api.tasks.*
 import org.gradle.kotlin.dsl.getByType
 import org.gradle.workers.WorkAction
@@ -18,6 +19,8 @@ import org.gradle.workers.WorkParameters
 import org.gradle.workers.WorkerExecutor
 import org.jetbrains.kotlin.ExecClang
 import org.jetbrains.kotlin.bitcode.CompileToBitcodePlugin
+import org.jetbrains.kotlin.konan.target.Family
+import org.jetbrains.kotlin.konan.target.HostManager
 import org.jetbrains.kotlin.konan.target.PlatformManager
 import java.io.File
 import javax.inject.Inject
@@ -57,13 +60,19 @@ private abstract class ClangFrontendJob : WorkAction<ClangFrontendJob.Parameters
  *
  * @see CompileToBitcodePlugin
  */
-abstract class ClangFrontend : DefaultTask() {
+@CacheableTask
+abstract class ClangFrontend @Inject constructor(
+        private val workerExecutor: WorkerExecutor,
+        private val objects: ObjectFactory,
+        private val layout: ProjectLayout,
+        providers: ProviderFactory,
+) : DefaultTask() {
     private data class WorkUnit(
             val inputFile: File,
             val outputFile: File,
     )
 
-    private val workUnits: Provider<List<WorkUnit>> = project.provider {
+    private val workUnits: Provider<List<WorkUnit>> = providers.provider {
         val result = mutableListOf<WorkUnit>()
         inputFiles.visit {
             if (!isDirectory) {
@@ -87,13 +96,14 @@ abstract class ClangFrontend : DefaultTask() {
      */
     @get:SkipWhenEmpty
     @get:InputFiles
+    @get:PathSensitive(PathSensitivity.RELATIVE)
     abstract val inputFiles: ConfigurableFileTree
 
     /**
      * Bitcode files generated by clang.
      */
     @get:OutputFiles
-    val outputFiles: FileCollection = project.files(workUnits.map { it.map { workUnit -> workUnit.outputFile } })
+    val outputFiles: FileCollection = layout.files(workUnits.map { it.map { workUnit -> workUnit.outputFile } })
 
     /**
      * Will select the appropriate compiler and additional flags.
@@ -108,13 +118,12 @@ abstract class ClangFrontend : DefaultTask() {
      * Currently only `clang` and `clang++` are supported.
      */
     @get:Input
-    abstract val compiler: Property<String>
+    val compiler: Property<String> = objects.property(String::class.java)
 
     /**
      * Extra arguments for [compiler].
      */
-    // Marked as input via [compilerFlags].
-    @get:Internal
+    @get:Input
     abstract val arguments: ListProperty<String>
 
     /**
@@ -122,15 +131,16 @@ abstract class ClangFrontend : DefaultTask() {
      *
      * Will be passed to the compiler as `-I…` and will also be used to compute task dependencies: recompile if the headers change.
      */
-    // Marked as input via [headers] and [compilerFlags].
+    // Marked as input via [headers].
     @get:Internal
     abstract val headersDirs: ConfigurableFileCollection
 
     /**
      * Final computed compiler arguments.
      */
-    @get:Input
-    val compilerFlags: Provider<List<String>> = project.provider {
+    // Marked as input via [headers] and [arguments].
+    @get:Internal
+    val compilerFlags: Provider<List<String>> = providers.provider {
         listOfNotNull(
                 "-c",
                 "-emit-llvm"
@@ -143,18 +153,19 @@ abstract class ClangFrontend : DefaultTask() {
      * All inputs will be passed to the compiler as relative paths to this directory.
      */
     @get:Internal
-    abstract val workingDirectory: DirectoryProperty
+    val workingDirectory: DirectoryProperty = objects.directoryProperty()
 
     @get:Input
-    protected val workingDirectoryPath: Provider<String> = project.provider {
-        workingDirectory.get().asFile.absolutePath
+    protected val workingDirectoryPath: Provider<String> = workingDirectory.map {
+        it.asFile.toRelativeString(layout.projectDirectory.asFile)
     }
 
     /**
      * Computed header files used for task dependencies tracking.
      */
     @get:InputFiles
-    protected val headers: Provider<List<File>> = project.provider {
+    @get:PathSensitive(PathSensitivity.RELATIVE)
+    protected val headers: Provider<FileTree> = providers.provider {
         // Not using clang's -M* flags because there's a problem with our current include system:
         // We allow includes relative to the current directory and also pass -I for each imported module
         // Given file tree:
@@ -177,17 +188,25 @@ abstract class ClangFrontend : DefaultTask() {
         }
         // Now add manually given header dirs.
         dirs.addAll(headersDirs.files)
-        dirs.flatMap { dir ->
-            project.fileTree(dir) {
-                include("**/*.h", "**/*.hpp")
-            }.files
+        layout.files(dirs).asFileTree.matching {
+            include("**/*.h", "**/*.hpp")
         }
     }
 
-    @get:Inject
-    protected abstract val workerExecutor: WorkerExecutor
-
     private val platformManager = project.extensions.getByType<PlatformManager>()
+    private val execClang by lazy { ExecClang.create(objects, platformManager) }
+
+    // TODO: Consider configuring full clang execution from the plugin instead.  
+    @get:InputFile
+    @get:PathSensitive(PathSensitivity.NONE)
+    val executable: Provider<RegularFile> = layout.file(compiler.map {
+        val executable = execClang.resolveExecutable(it)
+        val executableSuffix = when (HostManager.host.family) {
+            Family.MINGW -> ".exe"
+            else -> ""
+        }
+        File("$executable$executableSuffix")
+    })
 
     @TaskAction
     fun compile() {