compiler, runtime: Use function descriptors.

This changes the representation of a Go value of function type
from being a pointer to function code (like a C function
pointer) to being a pointer to a struct.  The first field of
the struct points to the function code.  The remaining fields,
if any, are the addresses of variables referenced in enclosing
functions.  For each call to a function, the address of the
function descriptor is passed as the last argument.

This lets us avoid generating trampolines, and removes the use
of writable/executable sections of the heap.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@200181 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 8 insertions, 5 deletions

diff --git a/libgo/runtime/time.goc b/libgo/runtime/time.goc
index 9a5cbdfed3b..e9f087ac884 100644
--- a/libgo/runtime/time.goc
+++ b/libgo/runtime/time.goc
@@ -49,13 +49,16 @@ static void siftdown(int32);
 
 // Ready the goroutine e.data.
 static void
-ready(int64 now, Eface e)
+ready(int64 now, Eface e, void *closure)
 {
 	USED(now);
+	USED(closure);
 
 	runtime_ready(e.__object);
 }
 
+static FuncVal readyv = {(void(*)(void))ready};
+
 // Put the current goroutine to sleep for ns nanoseconds.
 void
 runtime_tsleep(int64 ns, const char *reason)
@@ -70,7 +73,7 @@ runtime_tsleep(int64 ns, const char *reason)
 
 	t.when = runtime_nanotime() + ns;
 	t.period = 0;
-	t.f = ready;
+	t.fv = &readyv;
 	t.arg.__object = g;
 	runtime_lock(&timers);
 	addtimer(&t);
@@ -158,7 +161,7 @@ timerproc(void* dummy __attribute__ ((unused)))
 {
 	int64 delta, now;
 	Timer *t;
-	void (*f)(int64, Eface);
+	void (*f)(int64, Eface, void *);
 	Eface arg;
 
 	for(;;) {
@@ -184,12 +187,12 @@ timerproc(void* dummy __attribute__ ((unused)))
 				siftdown(0);
 				t->i = -1;  // mark as removed
 			}
-			f = t->f;
+			f = (void*)t->fv->fn;
 			arg = t->arg;
 			runtime_unlock(&timers);
 			if(raceenabled)
 				runtime_raceacquire(t);
-			f(now, arg);
+			f(now, arg, &t->fv);
 			runtime_lock(&timers);
 		}
 		if(delta < 0) {