Disable the GC pump by default. Fixes #4772. (#4781)

Fixes https://github.com/xamarin/xamarin-macios/issues/4772

runtime/runtime.m

@@ -38,9 +38,7 @@ bool xamarin_detect_unified_build = false;
 #if MONOMAC
 bool xamarin_use_new_assemblies = false;
 #endif
-#if MONOTOUCH && DEBUG && (defined (__i386__) || defined (__x86_64__))
-bool xamarin_gc_pump = true;
-#else
+#if DEBUG
 bool xamarin_gc_pump = false;
 #endif
 #if MONOMAC
@@ -2216,8 +2214,10 @@ xamarin_get_is_unified ()
 void
 xamarin_set_gc_pump_enabled (bool value)
 {
+#if DEBUG
 	// COOP: no managed memory access: any mode.
 	xamarin_gc_pump = value;
+#endif
 }
 
 const char *

runtime/xamarin/main.h

@@ -51,7 +51,9 @@ extern bool xamarin_use_new_assemblies;
 #else
 	#define xamarin_use_new_assemblies 1
 #endif
+#if DEBUG
 extern bool xamarin_gc_pump;
+#endif
 extern bool xamarin_debug_mode;
 extern bool xamarin_disable_lldb_attach;
 #if MONOMAC

tests/mtouch/MTouch.cs

@@ -702,6 +702,21 @@ public class B : A {}
 			}
 		}
 
+		[Test]
+		public void MT0032 ()
+		{
+			using (var mtouch = new MTouchTool ()) {
+				mtouch.Debug = false;
+				mtouch.CustomArguments = new string[] { "--debugtrack:true" };
+				mtouch.WarnAsError = new int[] { 32 };
+				mtouch.CreateTemporaryApp ();
+				mtouch.AssertExecuteFailure (MTouchAction.BuildSim, "build");
+				mtouch.AssertError (32, "The option '--debugtrack' is ignored unless '--debug' is also specified.");
+				mtouch.AssertErrorCount (1);
+				mtouch.AssertWarningCount (0);
+			}
+		}
+
 		[Test]
 		[TestCase (Profile.iOS, Profile.tvOS)]
 		[TestCase (Profile.iOS, Profile.watchOS)]

tools/mtouch/Application.cs

@@ -1124,15 +1124,10 @@ namespace Xamarin.Bundler {
 				BitCodeMode = BitCodeMode.LLVMOnly;
 			}
 
-			if (EnableDebug) {
-				if (!DebugTrack.HasValue) {
-					DebugTrack = IsSimulatorBuild;
-				}
-			} else {
-				if (DebugTrack.HasValue) {
-					ErrorHelper.Warning (32, "The option '--debugtrack' is ignored unless '--debug' is also specified.");
-				}
+			if (!DebugTrack.HasValue) {
 				DebugTrack = false;
+			} else if (DebugTrack.Value && !EnableDebug) {
+				ErrorHelper.Warning (32, "The option '--debugtrack' is ignored unless '--debug' is also specified.");
 			}
 
 			if (EnableAsmOnlyBitCode)

tools/mtouch/mtouch.cs

@@ -1004,8 +1004,8 @@ namespace Xamarin.Bundler
 			{ "nofastsim", "Do not run the simulator fast-path build", v => app.NoFastSim = true },
 			{ "nodevcodeshare", "Do not share native code between extensions and main app.", v => app.NoDevCodeShare = true },
 			{ "nolink", "Do not link the assemblies", v => app.LinkMode = LinkMode.None },
-			{ "nodebugtrack", "Disable debug tracking of object resurrection bugs", v => app.DebugTrack = false },
-			{ "debugtrack:", "Enable debug tracking of object resurrection bugs (enabled by default for the simulator)", v => { app.DebugTrack = ParseBool (v, "--debugtrack"); } },
+			{ "nodebugtrack", "Disable debug tracking of object resurrection bugs [DEPRECATED - already disabled by default]", v => app.DebugTrack = false, true },
+			{ "debugtrack:", "Enable debug tracking of object resurrection bugs", v => { app.DebugTrack = ParseBool (v, "--debugtrack"); } },
 			{ "linkerdumpdependencies", "Dump linker dependencies for linker-analyzer tool", v => app.LinkerDumpDependencies = true },
 			{ "linksdkonly", "Link only the SDK assemblies", v => app.LinkMode = LinkMode.SDKOnly },
 			{ "linkskip=", "Skip linking of the specified assembly", v => app.LinkSkipped.Add (v) },