JS IR IC: report cache validataion duration when up-to-date

compiler/cli/cli-js/src/org/jetbrains/kotlin/cli/js/K2JsIrCompiler.kt

@@ -201,18 +201,21 @@ class K2JsIrCompiler : CLICompiler<K2JSCompilerArguments>() {
             }
 
             val start = System.currentTimeMillis()
-            buildCache(
-                cachePath = outputFilePath,
-                project = projectJs,
-                mainModule = mainModule,
-                analyzer = AnalyzerWithCompilerReport(config.configuration),
-                configuration = config.configuration,
-                dependencies = libraries,
-                friendDependencies = friendLibraries,
-                icCache = checkCaches(libraries, icCaches, skipLib = mainModule.libPath)
-            )
-
-            messageCollector.report(INFO, "IC cache building duration: ${System.currentTimeMillis() - start}ms")
+            if (buildCache(
+                    cachePath = outputFilePath,
+                    project = projectJs,
+                    mainModule = mainModule,
+                    analyzer = AnalyzerWithCompilerReport(config.configuration),
+                    configuration = config.configuration,
+                    dependencies = libraries,
+                    friendDependencies = friendLibraries,
+                    icCache = checkCaches(libraries, icCaches, skipLib = mainModule.libPath)
+                )
+            ) {
+                messageCollector.report(INFO, "IC cache building duration: ${System.currentTimeMillis() - start}ms")
+            } else {
+                messageCollector.report(INFO, "IC cache up-to-date check duration: ${System.currentTimeMillis() - start}ms")
+            }
             return OK
         }
 

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/ic/fileUtil.kt

@@ -21,6 +21,7 @@ import kotlin.random.nextULong
 private val compilerVersion = Random.nextULong()
 
 // TODO more parameters for lowerings
+// Returns true if caches were built. False if caches were up-to-date.
 fun buildCache(
     cachePath: String,
     project: Project,
@@ -32,7 +33,7 @@ fun buildCache(
     exportedDeclarations: Set<FqName> = emptySet(),
     forceClean: Boolean = false,
     icCache: IcCacheInfo = IcCacheInfo.EMPTY,
-) {
+): Boolean {
     val dependencyHashes = dependencies.mapNotNull {
         val path = File(it).canonicalPath
         icCache.md5[path]
@@ -42,7 +43,7 @@ fun buildCache(
 
     if (!forceClean) {
         val oldCacheInfo = CacheInfo.load(cachePath)
-        if (oldCacheInfo != null && md5 == oldCacheInfo.md5) return
+        if (oldCacheInfo != null && md5 == oldCacheInfo.md5) return false
     }
 
     val icDir = File(cachePath)
@@ -54,6 +55,8 @@ fun buildCache(
     icData.writeTo(File(cachePath))
 
     CacheInfo(cachePath, mainModule.libPath, md5).save()
+
+    return true
 }
 
 private fun File.md5(additional: Iterable<ULong> = emptyList()): ULong {