JIT support in iOS (#15224)

* Use AltKit to try to enable JIT on iOS

* libretro: Add API to check JIT availability on iOS

libretro-common/include/libretro.h

@@ -1793,6 +1793,12 @@ enum retro_mod
                                              * this environment call to query support.
                                              */
 
+#define RETRO_ENVIRONMENT_GET_JIT_CAPABLE 74
+                                           /* bool * --
+                                            * Result is set to true if the frontend has already verified JIT can be
+                                            * used, mainly for use iOS/tvOS. On other platforms the result is true.
+                                            */
+
 
 /* VFS functionality */
 

pkg/apple/JITSupport.h

@@ -11,7 +11,8 @@
 
 #include <stdbool.h>
 
-static bool jb_has_debugger_attached(void);
+bool jb_has_debugger_attached(void);
 bool jb_enable_ptrace_hack(void);
+void jb_start_altkit(void);
 
 #endif /* JITSupport_h */

pkg/apple/JITSupport.m

@@ -16,6 +16,12 @@
 #include <mach-o/getsect.h>
 #include <pthread.h>
 
+#if defined(HAVE_ALTKIT)
+@import AltKit;
+#endif
+
+#include "../../verbosity.h"
+
 extern int csops(pid_t pid, unsigned int ops, void * useraddr, size_t usersize);
 extern boolean_t exc_server(mach_msg_header_t *, mach_msg_header_t *);
 extern int ptrace(int request, pid_t pid, caddr_t addr, int data);
@@ -32,7 +38,7 @@ static void *exception_handler(void *argument) {
     return NULL;
 }
 
-static bool jb_has_debugger_attached(void) {
+bool jb_has_debugger_attached(void) {
     int flags;
     return !csops(getpid(), CS_OPS_STATUS, &flags, sizeof(flags)) && flags & CS_DEBUGGED;
 }
@@ -70,7 +76,33 @@ bool jb_enable_ptrace_hack(void) {
         task_set_exception_ports(mach_task_self(), EXC_MASK_SOFTWARE, port, EXCEPTION_DEFAULT, THREAD_STATE_NONE);
         pthread_t thread;
         pthread_create(&thread, NULL, exception_handler, (void *)&port);
+    } else {
+        // JIT code frequently causes an EXC_BAD_ACCESS exception that lldb
+        // cannot be convinced to ignore. Instead we can set up a nul handler
+        // that effectively causes it to be ignored. Note that this sometimes
+        // also hides actual crashes from the debugger.
+        task_set_exception_ports(mach_task_self(), EXC_MASK_BAD_ACCESS, MACH_PORT_NULL, EXCEPTION_DEFAULT, THREAD_STATE_NONE);
     }
     
     return true;
 }
+
+void jb_start_altkit(void) {
+#if HAVE_ALTKIT
+   [[ALTServerManager sharedManager] autoconnectWithCompletionHandler:^(ALTServerConnection *connection, NSError *error) {
+      if (error)
+         return;
+
+      [connection enableUnsignedCodeExecutionWithCompletionHandler:^(BOOL success, NSError *error) {
+         if (success)
+            [[ALTServerManager sharedManager] stopDiscovering];
+         else
+            RARCH_WARN("AltServer failed: %s\n", [error.description UTF8String]);
+
+         [connection disconnect];
+      }];
+   }];
+
+   [[ALTServerManager sharedManager] startDiscovering];
+#endif
+}

pkg/apple/LLDBInitFile

@@ -0,0 +1 @@
+breakpoint set --func-regex "^(NS|UI)ApplicationMain$" --command "process handle --pass true --stop false SIGBUS" --auto-continue true

pkg/apple/RetroArch_iOS13.xcodeproj/project.pbxproj

@@ -10,6 +10,7 @@
 		0714E7142983A5AC00E6B45B /* libMoltenVK.dylib in Frameworks */ = {isa = PBXBuildFile; fileRef = 0714E7132983A5AC00E6B45B /* libMoltenVK.dylib */; };
 		0714E7152983A5E500E6B45B /* libMoltenVK.dylib in Embed Libraries */ = {isa = PBXBuildFile; fileRef = 0714E7132983A5AC00E6B45B /* libMoltenVK.dylib */; settings = {ATTRIBUTES = (CodeSignOnCopy, ); }; };
 		07B7872D29E8FE8F0088B74F /* filters in Resources */ = {isa = PBXBuildFile; fileRef = 07B7872C29E8FE8F0088B74F /* filters */; };
+		07EB0FA429F761B800D87936 /* AltKit in Frameworks */ = {isa = PBXBuildFile; productRef = 07EB0FA329F761B800D87936 /* AltKit */; };
 		9204BE0D1D319EF300BD49DB /* griffin_objc.m in Sources */ = {isa = PBXBuildFile; fileRef = 50521A431AA23BF500185CC9 /* griffin_objc.m */; };
 		9204BE101D319EF300BD49DB /* griffin.c in Sources */ = {isa = PBXBuildFile; fileRef = 501232C9192E5FC40063A359 /* griffin.c */; };
 		9204BE121D319EF300BD49DB /* libz.dylib in Frameworks */ = {isa = PBXBuildFile; fileRef = 5040F04F1AE47ED4006F6972 /* libz.dylib */; };
@@ -466,6 +467,7 @@
 				9204BE1B1D319EF300BD49DB /* CoreAudio.framework in Frameworks */,
 				9204BE1C1D319EF300BD49DB /* UIKit.framework in Frameworks */,
 				9204BE1D1D319EF300BD49DB /* Foundation.framework in Frameworks */,
+				07EB0FA429F761B800D87936 /* AltKit in Frameworks */,
 				9204BE1E1D319EF300BD49DB /* CoreGraphics.framework in Frameworks */,
 				9204BE1F1D319EF300BD49DB /* GLKit.framework in Frameworks */,
 				9204BE201D319EF300BD49DB /* OpenGLES.framework in Frameworks */,
@@ -1251,6 +1253,9 @@
 				9292D6F028F549D200E47A75 /* PBXTargetDependency */,
 			);
 			name = RetroArchiOS;
+			packageProductDependencies = (
+				07EB0FA329F761B800D87936 /* AltKit */,
+			);
 			productName = RetroArch;
 			productReference = 9204BE2B1D319EF300BD49DB /* RetroArch.app */;
 			productType = "com.apple.product-type.application";
@@ -1328,6 +1333,9 @@
 				Base,
 			);
 			mainGroup = 96AFAE1A16C1D4EA009DE44C;
+			packageReferences = (
+				07EB0FA229F761B800D87936 /* XCRemoteSwiftPackageReference "AltKit" */,
+			);
 			productRefGroup = 96AFAE2616C1D4EA009DE44C /* Products */;
 			projectDirPath = "";
 			projectRoot = "";
@@ -1565,6 +1573,7 @@
 					"-DGLES_SILENCE_DEPRECATION",
 					"-DGLSLANG_OSINCLUDE_UNIX",
 					"-DHAVE_7ZIP",
+					"-DHAVE_ALTKIT",
 					"-DHAVE_AUDIOMIXER",
 					"-DHAVE_BTSTACK",
 					"-DHAVE_BUILTINGLSLANG",
@@ -1706,6 +1715,7 @@
 					"-DGLES_SILENCE_DEPRECATION",
 					"-DGLSLANG_OSINCLUDE_UNIX",
 					"-DHAVE_7ZIP",
+					"-DHAVE_ALTKIT",
 					"-DHAVE_AUDIOMIXER",
 					"-DHAVE_BTSTACK",
 					"-DHAVE_BUILTINGLSLANG",
@@ -2471,6 +2481,25 @@
 			defaultConfigurationName = Release;
 		};
 /* End XCConfigurationList section */
+
+/* Begin XCRemoteSwiftPackageReference section */
+		07EB0FA229F761B800D87936 /* XCRemoteSwiftPackageReference "AltKit" */ = {
+			isa = XCRemoteSwiftPackageReference;
+			repositoryURL = "https://github.com/rileytestut/AltKit.git";
+			requirement = {
+				kind = upToNextMajorVersion;
+				minimumVersion = 0.0.1;
+			};
+		};
+/* End XCRemoteSwiftPackageReference section */
+
+/* Begin XCSwiftPackageProductDependency section */
+		07EB0FA329F761B800D87936 /* AltKit */ = {
+			isa = XCSwiftPackageProductDependency;
+			package = 07EB0FA229F761B800D87936 /* XCRemoteSwiftPackageReference "AltKit" */;
+			productName = AltKit;
+		};
+/* End XCSwiftPackageProductDependency section */
 	};
 	rootObject = 96AFAE1C16C1D4EA009DE44C /* Project object */;
 }

pkg/apple/RetroArch_iOS13.xcodeproj/xcshareddata/xcschemes/RetroArch iOS Debug.xcscheme

@@ -43,6 +43,7 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      customLLDBInitFile = "$(SRCROOT)/LLDBInitFile"
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"

pkg/apple/RetroArch_iOS13.xcodeproj/xcshareddata/xcschemes/RetroArch iOS Release.xcscheme

@@ -43,6 +43,7 @@
       buildConfiguration = "Release"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      customLLDBInitFile = "$(SRCROOT)/LLDBInitFile"
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"

pkg/apple/iOS/Info.plist

@@ -44,6 +44,14 @@
 	<true/>
 	<key>LSSupportsOpeningDocumentsInPlace</key>
 	<true/>
+	<key>NSBonjourServices</key>
+	<array>
+		<string>_altserver._tcp</string>
+	</array>
+   <key>NSLocalNetworkUsageDescription</key>
+   <string>RetroArch uses the local network to find and communicate with AltServer to enable JIT.</string>
+   <key>ALTDeviceID</key>
+   <string></string>
 	<key>NSCameraUsageDescription</key>
 	<string>YES</string>
 	<key>UIApplicationExitsOnSuspend</key>

runloop.c

@@ -241,6 +241,10 @@
 #include "lakka.h"
 #endif
 
+#if defined(HAVE_COCOATOUCH) && TARGET_OS_IOS
+#include "JITSupport.h"
+#endif
+
 #define SHADER_FILE_WATCH_DELAY_MSEC 500
 
 #define QUIT_DELAY_USEC 3 * 1000000 /* 3 seconds */
@@ -3378,6 +3382,16 @@ bool runloop_environment_cb(unsigned cmd, void *data)
          }
          break;
 
+      case RETRO_ENVIRONMENT_GET_JIT_CAPABLE:
+         {
+#if defined(HAVE_COCOATOUCH) && TARGET_OS_IOS
+            *(bool*)data             = jb_has_debugger_attached();
+#else
+            *(bool*)data             = true;
+#endif
+         }
+         break;
+
       default:
          RARCH_LOG("[Environ]: UNSUPPORTED (#%u).\n", cmd);
          return false;

ui/drivers/ui_cocoatouch.m

@@ -436,6 +436,10 @@ enum
    [self refreshSystemConfig];
    [self showGameView];
 
+#if TARGET_OS_IOS
+   jb_start_altkit();
+#endif
+
    rarch_main(argc, argv, NULL);
 
    rarch_start_draw_observer();