Better stack overflow checking

Author: aykevl

ports/unix/main.c

@@ -10,12 +10,22 @@ int main(int argc, char **argv) {
 return 0;
 }
 
+static void tinygo_check_canary() {
+if (goroutine->canary != STACK_CANARY) {
+Eface err;
+runtime_newErrorCString("stack overflow", &err);
+runtime_Panic(err, true);
+}
+}
+
 __attribute__((noreturn))
 void tinygo_goroutine_exit() {
 goroutine_work_counter++;
 
 DEBUG_printf("-- exit goroutine %d\n", goroutine->num);
 
+tinygo_check_canary();
+
 // cleanup goroutine
 if (goroutine->next == goroutine) {
 // This is the last goroutine.
@@ -53,6 +63,10 @@ void tinygo_run_internal(func fn, void *arg) {
 void tinygo_go(void *fn, void *arg, void *created_by) {
 static size_t goroutine_counter = 0;
 
+if (goroutine != NULL) {
+tinygo_check_canary();
+}
+
 // Allocate and init goroutine
 goroutine_t *r = tinygo_alloc(sizeof(goroutine_t));
 r->num = ++goroutine_counter;
@@ -84,11 +98,7 @@ void tinygo_block() {
 if (goroutine == goroutine->next) {
 tinygo_deadlocked();
 }
-if (goroutine->canary != STACK_CANARY) {
-Eface err;
-runtime_newErrorCString("stack overflow", &err);
-runtime_Panic(err, true);
-}
+tinygo_check_canary();
 goroutine_t *old = goroutine;
 goroutine_t *new = goroutine->next;
 goroutine = new;