keep a map of thread ids to vm pointers. use this to look up the correct VM to handle mach exceptions on os x

vm/factor.cpp

@@ -4,6 +4,7 @@ namespace factor
 {
 
 factor_vm *vm;
+unordered_map<THREADHANDLE, factor_vm*> thread_vms;
 
 void init_globals()
 {
@@ -221,23 +222,30 @@ struct startargs {
 	vm_char **argv;
 };
 
-// arg must be new'ed because we're going to delete it!
+factor_vm * new_factor_vm()
-void* start_standalone_factor_thread(void *arg) 
 {
 	factor_vm *newvm = new factor_vm;
 	register_vm_with_thread(newvm);
+	thread_vms[thread_id()] = newvm;
+
+	return newvm;
+}
+
+// arg must be new'ed because we're going to delete it!
+void* start_standalone_factor_thread(void *arg) 
+{
+	factor_vm *newvm = new_factor_vm();
 	startargs *args = (startargs*) arg;
-        int argc = args->argc; vm_char **argv = args->argv;
+	int argc = args->argc; vm_char **argv = args->argv;
-        delete args;
+	delete args;
 	newvm->start_standalone_factor(argc, argv);
 	return 0;
 }
 
 VM_C_API void start_standalone_factor(int argc, vm_char **argv)
 {
-	factor_vm *newvm = new factor_vm;
+	factor_vm *newvm = new_factor_vm();
 	vm = newvm;
-	register_vm_with_thread(newvm);
 	return newvm->start_standalone_factor(argc,argv);
 }
 

vm/mach_signal.cpp

@@ -33,7 +33,7 @@ void factor_vm::call_fault_handler(
 	exception_data_type_t code,
 	MACH_EXC_STATE_TYPE *exc_state,
 	MACH_THREAD_STATE_TYPE *thread_state,
-        MACH_FLOAT_STATE_TYPE *float_state)
+	MACH_FLOAT_STATE_TYPE *float_state)
 {
 	/* There is a race condition here, but in practice an exception
 	delivered during stack frame setup/teardown or while transitioning
@@ -68,17 +68,23 @@ void factor_vm::call_fault_handler(
 	}
 }
 
-static void call_fault_handler(exception_type_t exception,
+static void call_fault_handler(
+	mach_port_t thread,
+	exception_type_t exception,
 	exception_data_type_t code,
 	MACH_EXC_STATE_TYPE *exc_state,
 	MACH_THREAD_STATE_TYPE *thread_state,
 	MACH_FLOAT_STATE_TYPE *float_state)
 {
-	SIGNAL_VM_PTR()->call_fault_handler(exception,code,exc_state,thread_state,float_state);
+	THREADHANDLE thread_id = pthread_from_mach_thread_np(thread);
+	assert(thread_id);
+	unordered_map<THREADHANDLE, factor_vm*>::const_iterator vm = thread_vms.find(thread_id);
+	if (vm != thread_vms.end())
+	    vm->second->call_fault_handler(exception,code,exc_state,thread_state,float_state);
 }
 
 /* Handle an exception by invoking the user's fault handler and/or forwarding
-the duty to the previously installed handlers.  */
+the duty to the previously installed handlers.	*/
 extern "C"
 kern_return_t
 catch_exception_raise (mach_port_t exception_port,
@@ -95,7 +101,7 @@ catch_exception_raise (mach_port_t exception_port,
 
 	/* Get fault information and the faulting thread's register contents..
 	
-	See http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/thread_get_state.html.  */
+	See http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/thread_get_state.html.	*/
 	exc_state_count = MACH_EXC_STATE_COUNT;
 	if (thread_get_state (thread, MACH_EXC_STATE_FLAVOR,
 			      (natural_t *)&exc_state, &exc_state_count)
@@ -116,7 +122,7 @@ catch_exception_raise (mach_port_t exception_port,
 		return KERN_FAILURE;
 	}
 
-        float_state_count = MACH_FLOAT_STATE_COUNT;
+	float_state_count = MACH_FLOAT_STATE_COUNT;
 	if (thread_get_state (thread, MACH_FLOAT_STATE_FLAVOR,
 			      (natural_t *)&float_state, &float_state_count)
 		!= KERN_SUCCESS)
@@ -128,11 +134,11 @@ catch_exception_raise (mach_port_t exception_port,
 
 	/* Modify registers so to have the thread resume executing the
 	fault handler */
-	call_fault_handler(exception,code[0],&exc_state,&thread_state,&float_state);
+	call_fault_handler(thread,exception,code[0],&exc_state,&thread_state,&float_state);
 
 	/* Set the faulting thread's register contents..
 	
-	See http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/thread_set_state.html.  */
+	See http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/thread_set_state.html.	*/
 	if (thread_set_state (thread, MACH_FLOAT_STATE_FLAVOR,
 			      (natural_t *)&float_state, float_state_count)
 		!= KERN_SUCCESS)
@@ -167,7 +173,7 @@ mach_exception_thread (void *arg)
 			char data[1024];
 		}
 		msg;
-		/* Buffer for a reply message.  */
+		/* Buffer for a reply message.	*/
 		struct
 		{
 			mach_msg_header_t head;
@@ -230,7 +236,7 @@ void mach_initialize ()
 	for a particular thread.  This has the effect that when our exception
 	port gets the message, the thread specific exception port has already
 	been asked, and we don't need to bother about it.
-	See http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/task_set_exception_ports.html.  */
+	See http://web.mit.edu/darwin/src/modules/xnu/osfmk/man/task_set_exception_ports.html.	*/
 	if (task_set_exception_ports (self, mask, our_exception_port,
 		EXCEPTION_DEFAULT, MACHINE_THREAD_STATE)
 		!= KERN_SUCCESS)

vm/os-unix.hpp

@@ -45,7 +45,7 @@ typedef char symbol_char;
 typedef pthread_t THREADHANDLE;
 
 THREADHANDLE start_thread(void *(*start_routine)(void *),void *args);
-pthread_t thread_id();
+inline static THREADHANDLE thread_id() { return pthread_self(); }
 
 void unix_init_signals();
 void signal_handler(int signal, siginfo_t* siginfo, void* uap);

vm/os-windows-nt.hpp

@@ -29,6 +29,7 @@ FACTOR_STDCALL LONG exception_handler(PEXCEPTION_POINTERS pe);
 typedef HANDLE THREADHANDLE;
 
 THREADHANDLE start_thread(void *(*start_routine)(void *),void *args);
+inline static THREADHANDLE thread_id() { return GetCurrentThread(); }
 
 void init_platform_globals();
 struct factor_vm;

vm/vm.hpp

@@ -796,4 +796,6 @@ struct factor_vm
   #define SIGNAL_VM_PTR() tls_vm()
 #endif
 
+extern unordered_map<THREADHANDLE, factor_vm*> thread_vms;
+
 }