vm: write signals to pipe immediately

The whole point is to wake up the mx without waiting for the next safepoint derp

vm/os-unix.cpp

@@ -180,11 +180,19 @@ void synchronous_signal_handler(int signal, siginfo_t *siginfo, void *uap)
 		fatal_error("Foreign thread received signal", signal);
 }
 
+void safe_write(int fd, void *data, ssize_t size);
+
+static void enqueue_signal(factor_vm *vm, int signal)
+{
+	if (vm->signal_pipe_output != 0)
+		safe_write(vm->signal_pipe_output, &signal, sizeof(int));
+}
+
 void enqueue_signal_handler(int signal, siginfo_t *siginfo, void *uap)
 {
 	factor_vm *vm = current_vm_p();
 	if (vm)
-		vm->safepoint.enqueue_signal(signal);
+		enqueue_signal(vm, signal);
 	else
 		fatal_error("Foreign thread received signal", signal);
 }
@@ -193,7 +201,10 @@ void fep_signal_handler(int signal, siginfo_t *siginfo, void *uap)
 {
 	factor_vm *vm = current_vm_p();
 	if (vm)
-		vm->safepoint.enqueue_fep(signal);
+	{
+		vm->safepoint.enqueue_fep();
+		enqueue_signal(vm, signal);
+	}
 	else
 		fatal_error("Foreign thread received signal", signal);
 }
@@ -268,7 +279,7 @@ static void safe_pipe(int *in, int *out)
 static void init_signal_pipe(factor_vm *vm)
 {
 	safe_pipe(&vm->signal_pipe_input, &vm->signal_pipe_output);
-	vm->special_objects[OBJ_SIGNAL_PIPE] = tag_fixnum(vm->signal_pipe_output);
+	vm->special_objects[OBJ_SIGNAL_PIPE] = tag_fixnum(vm->signal_pipe_input);
 }
 
 void factor_vm::unix_init_signals()
@@ -443,14 +454,4 @@ void open_console()
 	start_thread(stdin_loop,NULL);
 }
 
-void safepoint_state::report_signal(int fd) volatile
-{
-	int signal = (int)atomic::load(&queued_signal);
-	if (signal != 0)
-	{
-		safe_write(fd, &signal, sizeof(int));
-		atomic::store(&queued_signal, 0);
-	}
-}
-
 }

vm/os-windows.cpp

@@ -169,7 +169,6 @@ void factor_vm::move_file(const vm_char *path1, const vm_char *path2)
 }
 
 void factor_vm::init_signals() {}
-void safepoint_state::report_signal(int fd) volatile {}
 
 THREADHANDLE start_thread(void *(*start_routine)(void *), void *args)
 {
@@ -289,7 +288,7 @@ static BOOL WINAPI ctrl_handler(DWORD dwCtrlType)
 		threads. */
 		assert(thread_vms.size() == 1);
 		factor_vm *vm = thread_vms.begin()->second;
-		vm->safepoint.enqueue_fep(0);
+		vm->safepoint.enqueue_fep();
 		return TRUE;
 	}
 	default:

vm/safepoints.cpp

@@ -8,19 +8,11 @@ void safepoint_state::enqueue_safepoint() volatile
 	parent->code->guard_safepoint();
 }
 
-void safepoint_state::enqueue_fep(cell signal) volatile
+void safepoint_state::enqueue_fep() volatile
 {
 	if (parent->fep_p)
 		fatal_error("Low-level debugger interrupted", 0);
 	atomic::store(&fep_p, true);
-	if (signal != 0)
-		atomic::store(&queued_signal, signal);
-	enqueue_safepoint();
-}
-
-void safepoint_state::enqueue_signal(cell signal) volatile
-{
-	atomic::store(&queued_signal, signal);
 	enqueue_safepoint();
 }
 
@@ -28,9 +20,9 @@ void safepoint_state::enqueue_samples(cell samples, cell pc, bool foreign_thread
 {
 	if (atomic::load(&parent->sampling_profiler_p))
 	{
-		atomic::add(&sample_counts.sample_count, samples);
+		atomic::fetch_add(&sample_counts.sample_count, samples);
 		if (foreign_thread_p)
-			atomic::add(&sample_counts.foreign_thread_sample_count, samples);
+			atomic::fetch_add(&sample_counts.foreign_thread_sample_count, samples);
 		else {
 			if (atomic::load(&parent->current_gc_p))
 				atomic::fetch_add(&sample_counts.gc_sample_count, samples);
@@ -47,8 +39,6 @@ void safepoint_state::handle_safepoint() volatile
 {
 	parent->code->unguard_safepoint();
 
-	report_signal(parent->signal_pipe_input);
-
 	if (atomic::load(&fep_p))
 	{
 		if (atomic::load(&parent->sampling_profiler_p))

vm/safepoints.hpp

@@ -6,13 +6,11 @@ struct safepoint_state
 	factor_vm *parent;
 
 	cell fep_p;
-	cell queued_signal;
 	profiling_sample_count sample_counts;
 
 	safepoint_state(factor_vm *parent) :
 		parent(parent),
 		fep_p(false),
-		queued_signal(0),
 		sample_counts()
 	{
 	}
@@ -21,12 +19,7 @@ struct safepoint_state
 
 	void enqueue_safepoint() volatile;
 	void enqueue_samples(cell samples, cell pc, bool foreign_thread_p) volatile;
-	void enqueue_fep(cell signal) volatile;
+	void enqueue_fep() volatile;
-
-	// os-*.cpp
-	void enqueue_signal(cell signal) volatile;
-	void report_signal(int fd) volatile;
-
 };
 
 }