bench: Add an unwinding benchmark

Author: brson

src/test/bench/task-perf-alloc-unwind.rs

@@ -0,0 +1,85 @@
+// xfail-win32
+
+use std;
+
+import tuple::{first, second};
+import std::list::{list, cons, nil};
+import std::time::precise_time_s;
+
+fn main() {
+    let (repeat, depth) = if os::getenv("RUST_BENCH").is_some() {
+        (50, 1000)
+    } else {
+        (10, 10)
+    };
+
+    run(repeat, depth);
+}
+
+fn run(repeat: int, depth: int) {
+    iter::repeat(repeat as uint) { ||
+        #debug("starting %.4f", precise_time_s());
+        task::try { ||
+            recurse_or_fail(depth, none)
+        };
+        #debug("stopping %.4f", precise_time_s());
+    }
+}
+
+type nillist = list<()>;
+
+// Filled with things that have to be unwound
+enum st {
+    st_({
+        box: @nillist,
+        unique: ~nillist,
+        fn_box: fn@() -> @nillist,
+        fn_unique: fn~() -> ~nillist,
+        tuple: (@nillist, ~nillist),
+        vec: [@nillist],
+        res: r
+    })
+}
+
+resource r(_l: @nillist) {
+}
+
+fn recurse_or_fail(depth: int, st: option<st>) {
+    if depth == 0 {
+        #debug("unwinding %.4f", precise_time_s());
+        fail;
+    } else {
+        let depth = depth - 1;
+
+        let st = alt st {
+          none {
+            st_({
+                box: @nil,
+                unique: ~nil,
+                fn_box: fn@() -> @nillist { @nil::<()> },
+                fn_unique: fn~() -> ~nillist { ~nil::<()> },
+                tuple: (@nil, ~nil),
+                vec: [@nil],
+                res: r(@nil)
+            })
+          }
+          some(st) {
+            let fn_box = st.fn_box;
+            let fn_unique = st.fn_unique;
+
+            st_({
+                box: @cons((), st.box),
+                unique: ~cons((), @*st.unique),
+                fn_box: fn@() -> @nillist { @cons((), fn_box()) },
+                fn_unique: fn~() -> ~nillist { ~cons((), @*fn_unique()) },
+                tuple: (@cons((), first(st.tuple)),
+                        ~cons((), @*second(st.tuple))),
+                vec: st.vec + [@cons((), st.vec.last())],
+                res: r(@cons((), *(st.res)))
+            })
+          }
+        };
+
+        recurse_or_fail(depth, some(st));
+    }
+}