test: Test hitting the dynamic linker in the red zone

src/rt/rust_builtin.cpp

@@ -273,6 +273,12 @@ debug_ptrcast(type_desc *from_ty,
     return ptr;
 }
 
+extern "C" CDECL void *
+debug_get_stk_seg() {
+    rust_task *task = rust_scheduler::get_task();
+    return task->stk;
+}
+
 extern "C" CDECL rust_vec*
 rust_list_files(rust_str *path) {
     rust_task *task = rust_scheduler::get_task();

src/rt/rust_upcall.cpp

@@ -222,7 +222,7 @@ upcall_call_shim_on_c_stack(void *args, void *fn_ptr) {
     // FIXME (1226) - The shim functions generated by rustc contain the
     // morestack prologue, so we need to let them know they have enough
     // stack.
-    //record_sp(0);
+    record_sp(0);
 
     rust_scheduler *sched = task->sched;
     try {
@@ -232,8 +232,8 @@ upcall_call_shim_on_c_stack(void *args, void *fn_ptr) {
         //task->record_stack_limit();
         throw;
     }
-    //task = rust_scheduler::get_task();
-    //task->record_stack_limit();
+    task = rust_scheduler::get_task();
+    task->record_stack_limit();
 }
 
 struct rust_new_stack2_args {

src/rt/rustrt.def.in

@@ -8,6 +8,7 @@ del_port
 debug_ptrcast
 debug_tag
 debug_tydesc
+debug_get_stk_seg
 do_gc
 drop_task
 get_port_id

src/test/run-pass/morestack6.rs

@@ -0,0 +1,81 @@
+// xfail-test
+// compile-flags:--stack-growth
+
+// This test attempts to force the dynamic linker to resolve
+// external symbols as close to the red zone as possible.
+
+use std;
+import std::task;
+import std::rand;
+
+native mod rustrt {
+    fn set_min_stack(size: uint);
+    fn debug_get_stk_seg() -> *u8;
+
+    fn unsupervise();
+    fn last_os_error() -> str;
+    fn rust_getcwd() -> str;
+    fn refcount(box: @int);
+    fn do_gc();
+    fn pin_task();
+    fn unpin_task();
+    fn get_task_id();
+    fn sched_threads();
+    fn rust_get_task();
+}
+
+fn calllink01() { rustrt::unsupervise(); }
+fn calllink02() { rustrt::last_os_error(); }
+fn calllink03() { rustrt::rust_getcwd(); }
+fn calllink04() { rustrt::refcount(@0); }
+fn calllink05() { rustrt::do_gc(); }
+fn calllink06() { rustrt::pin_task(); }
+fn calllink07() { rustrt::unpin_task(); }
+fn calllink08() { rustrt::get_task_id(); }
+fn calllink09() { rustrt::sched_threads(); }
+fn calllink10() { rustrt::rust_get_task(); }
+
+fn runtest(&&args:(fn(), u32)) {
+    let (f, frame_backoff) = args;
+    runtest2(f, frame_backoff, 0 as *u8);
+}
+
+fn runtest2(f: fn(), frame_backoff: u32, last_stk: *u8) -> u32 {
+    let curr_stk = rustrt::debug_get_stk_seg();
+    if (last_stk != curr_stk && last_stk != 0 as *u8) {
+        // We switched stacks, go back and try to hit the dynamic linker
+        frame_backoff
+    } else {
+        let frame_backoff = runtest2(f, frame_backoff, curr_stk);
+        if frame_backoff > 1u32 {
+            frame_backoff - 1u32
+        } else if frame_backoff == 1u32 {
+            f();
+            0u32
+        } else {
+            0u32
+        }
+    }
+}
+
+fn main() {
+    let fns = [
+        calllink01,
+        calllink02,
+        calllink03,
+        calllink04,
+        calllink05,
+        calllink06,
+        calllink07,
+        calllink08,
+        calllink09,
+        calllink10
+    ];
+    let rng = rand::mk_rng();
+    for f in fns {
+        let sz = rng.next() % 256u32 + 256u32;
+        let frame_backoff = rng.next() % 10u32 + 1u32;
+        rustrt::set_min_stack(sz as uint);
+        task::join(task::spawn_joinable((f, frame_backoff), runtest));
+    }
+}