[K/N] Enable CMS GC by default for the new MM

Issue #KT-50713 Fixed

kotlin-native/backend.native/cli.bc/src/org/jetbrains/kotlin/cli/bc/K2NativeCompilerArguments.kt

@@ -327,7 +327,7 @@ class K2NativeCompilerArguments : CommonCompilerArguments() {
     @Argument(value="-Xdestroy-runtime-mode", valueDescription = "<mode>", description = "When to destroy runtime. 'legacy' and 'on-shutdown' are currently supported. NOTE: 'legacy' mode is deprecated and will be removed.")
     var destroyRuntimeMode: String? = "on-shutdown"
 
-    @Argument(value="-Xgc", valueDescription = "<gc>", description = "GC to use, 'noop' and 'stms' are currently supported. Works only with -memory-model experimental")
+    @Argument(value="-Xgc", valueDescription = "<gc>", description = "GC to use, 'noop', 'stms' and 'cms' are currently supported. Works only with -memory-model experimental")
     var gc: String? = null
 
     @Argument(value = "-Xir-property-lazy-initialization", valueDescription = "{disable|enable}", description = "Initialize top level properties lazily per file")

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/KonanConfig.kt

@@ -86,7 +86,7 @@ class KonanConfig(val project: Project, val configuration: CompilerConfiguration
         val (gcFallbackReason, realGc) = when {
             configGc == GC.CONCURRENT_MARK_AND_SWEEP && !target.supportsThreads() ->
                 "Concurrent mark and sweep gc is not supported for this target. Fallback to Same thread mark and sweep is done" to GC.SAME_THREAD_MARK_AND_SWEEP
-            configGc == null -> null to GC.SAME_THREAD_MARK_AND_SWEEP
+            configGc == null -> null to GC.CONCURRENT_MARK_AND_SWEEP
             else -> null to configGc
         }
         if (gcFallbackReason != null) {

kotlin-native/runtime/src/gc/cms/cpp/ConcurrentMarkAndSweep.cpp

@@ -99,6 +99,7 @@ gc::ConcurrentMarkAndSweep::ConcurrentMarkAndSweep(
             }
         }
     });
+    RuntimeLogDebug({kTagGC}, "Concurrent Mark & Sweep GC initialized");
 }
 
 gc::ConcurrentMarkAndSweep::~ConcurrentMarkAndSweep() {

kotlin-native/runtime/src/gc/noop/cpp/NoOpGC.hpp

@@ -51,7 +51,9 @@ public:
     private:
     };
 
-    NoOpGC(mm::ObjectFactory<NoOpGC>&, GCScheduler&) noexcept {}
+    NoOpGC(mm::ObjectFactory<NoOpGC>&, GCScheduler&) noexcept {
+        RuntimeLogDebug({kTagGC}, "No-op GC initialized");
+    }
     ~NoOpGC() = default;
 
     GCScheduler& scheduler() noexcept { return scheduler_; }

kotlin-native/runtime/src/gc/stms/cpp/SameThreadMarkAndSweep.cpp

@@ -112,6 +112,7 @@ gc::SameThreadMarkAndSweep::SameThreadMarkAndSweep(
             RuntimeLogDebug({kTagGC}, "Scheduling GC by thread %d", konan::currentThreadId());
         }
     });
+    RuntimeLogDebug({kTagGC}, "Same thread Mark & Sweep GC initialized");
 }
 
 bool gc::SameThreadMarkAndSweep::PerformFullGC() noexcept {

native/native.tests/tests/org/jetbrains/kotlin/konan/blackboxtest/support/settings/TestProcessSettings.kt

@@ -87,7 +87,8 @@ internal enum class ThreadStateChecker(val compilerFlag: String?) {
 internal enum class GCType(val compilerFlag: String?) {
     UNSPECIFIED(null),
     NOOP("-Xgc=noop"),
-    STMS("-Xgc=stms");
+    STMS("-Xgc=stms"),
+    CMS("-Xgc=cms");
 
     override fun toString() = compilerFlag?.let { "($it)" }.orEmpty()
 }