Add more benchmarking

Including a rustc/llvm pathalogical case.

src/lib.rs

@@ -289,31 +289,33 @@ impl<'a, A: ?Sized + UncheckedAnyExt, V: IntoBox<A>> VacantEntry<'a, A, V> {
     }
 }
 
-#[cfg(feature = "bench")]
-#[bench]
-fn bench_insertion(b: &mut ::test::Bencher) {
+#[cfg(all(feature = "bench", test))]
+mod bench {
+    use AnyMap;
+    use test::Bencher;
+
+    #[bench]
+    fn insertion(b: &mut Bencher) {
         b.iter(|| {
             let mut data = AnyMap::new();
             for _ in 0..100 {
                 let _ = data.insert(42);
             }
         })
-}
+    }
 
-#[cfg(feature = "bench")]
-#[bench]
-fn bench_get_missing(b: &mut ::test::Bencher) {
+    #[bench]
+    fn get_missing(b: &mut Bencher) {
         b.iter(|| {
             let data = AnyMap::new();
             for _ in 0..100 {
                 assert_eq!(data.get(), None::<&i32>);
             }
         })
-}
+    }
 
-#[cfg(feature = "bench")]
-#[bench]
-fn bench_get_present(b: &mut ::test::Bencher) {
+    #[bench]
+    fn get_present(b: &mut Bencher) {
         b.iter(|| {
             let mut data = AnyMap::new();
             let _ = data.insert(42);
@@ -322,6 +324,68 @@ fn bench_get_present(b: &mut ::test::Bencher) {
                 assert_eq!(data.get(), Some(&42));
             }
         })
+    }
+
+    macro_rules! big_benchmarks {
+        ($name:ident, $($T:ident)*) => (
+            #[bench]
+            fn $name(b: &mut Bencher) {
+                $(
+                    #[derive(Debug, PartialEq)]
+                    struct $T(&'static str);
+
+                    impl Default for $T {
+                        fn default() -> $T {
+                            $T(stringify!($T))
+                        }
+                    }
+                )*
+
+                b.iter(|| {
+                    let mut data = AnyMap::new();
+                    $(
+                        assert_eq!(data.insert($T::default()), None::<$T>);
+                    )*
+                    $(
+                        assert_eq!(data.get(), Some(&$T::default()));
+                    )*
+                })
+            }
+        );
+    }
+
+    // Pathalogical rustc/llvm case here. This takes *absurdly* long to compile (it adds something
+    // like 100 seconds), peaking at over 1GB of RAM (though -Z time-passes doesn’t pick up on
+    // that, as it’s in the middle of the “llvm modules passes [0]” that it happens and it’s all
+    // freed at the end of that pass) and adding over 700KB to the final build. (3KB per type is
+    // more than I expected, reasonably or unreasonably.) TODO determine why and get it fixed.
+    //
+    // Selected rustc -Z time-passes output, with and without this block:
+    //
+    // - item-bodies checking:   0.4 seconds without,  5.2 seconds with;
+    // - borrow checking:        0.1 seconds without, 11   seconds with;
+    // - llvm module passes [0]: 2.5 seconds without, 49   seconds with;
+    // - codegen passes [0]:     0.6 seconds without, 11.2 seconds with.
+    //
+    // Very not good.
+    big_benchmarks! {
+        insert_and_get_on_260_types,
+        A0 B0 C0 D0 E0 F0 G0 H0 I0 J0 K0 L0 M0 N0 O0 P0 Q0 R0 S0 T0 U0 V0 W0 X0 Y0 Z0
+        A1 B1 C1 D1 E1 F1 G1 H1 I1 J1 K1 L1 M1 N1 O1 P1 Q1 R1 S1 T1 U1 V1 W1 X1 Y1 Z1
+        A2 B2 C2 D2 E2 F2 G2 H2 I2 J2 K2 L2 M2 N2 O2 P2 Q2 R2 S2 T2 U2 V2 W2 X2 Y2 Z2
+        A3 B3 C3 D3 E3 F3 G3 H3 I3 J3 K3 L3 M3 N3 O3 P3 Q3 R3 S3 T3 U3 V3 W3 X3 Y3 Z3
+        A4 B4 C4 D4 E4 F4 G4 H4 I4 J4 K4 L4 M4 N4 O4 P4 Q4 R4 S4 T4 U4 V4 W4 X4 Y4 Z4
+        A5 B5 C5 D5 E5 F5 G5 H5 I5 J5 K5 L5 M5 N5 O5 P5 Q5 R5 S5 T5 U5 V5 W5 X5 Y5 Z5
+        A6 B6 C6 D6 E6 F6 G6 H6 I6 J6 K6 L6 M6 N6 O6 P6 Q6 R6 S6 T6 U6 V6 W6 X6 Y6 Z6
+        A7 B7 C7 D7 E7 F7 G7 H7 I7 J7 K7 L7 M7 N7 O7 P7 Q7 R7 S7 T7 U7 V7 W7 X7 Y7 Z7
+        A8 B8 C8 D8 E8 F8 G8 H8 I8 J8 K8 L8 M8 N8 O8 P8 Q8 R8 S8 T8 U8 V8 W8 X8 Y8 Z8
+        A9 B9 C9 D9 E9 F9 G9 H9 I9 J9 K9 L9 M9 N9 O9 P9 Q9 R9 S9 T9 U9 V9 W9 X9 Y9 Z9
+    }
+
+    big_benchmarks! {
+        insert_and_get_on_26_types,
+        A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
+    }
 }
 
 #[cfg(test)]