Auto merge of #45162 - chrisvittal:mir-testing, r=nikomatsakis

Modify MIR testing to require consecutive lines

MIR testing now requires that lines be consecutive. To achive this,
instead of collecting the expected mir as a string, it is now wrapped in
an `ExpectedLine` enum, that is either `Elision` or `Text(T)` where `T:
AsRef<str>`. `Text` lines must be matched in order, unless separated by
`Elision` lines. Elision occurs lazily, that is, an Elision will skip
as few lines as possible.

To add a new elision marker. Put a comment containing only "..." and
whitespace in any MIR testing block. Like so:

```
// fn write_42(_1: *mut i32) -> bool {
//     ...
//     bb0: {
//         Validate(Acquire, [_1: *mut i32]);
//         Validate(Release, [_1: *mut i32]);
//         ...
//         return;
//     }
// }
```

Right now, all input before the line right after `// START` is elided,
and all input after the line right before `// END` is also not tested.

Many tests need to be updated. That will follow in the next commit.

cc #45153
r? @nikomatsakis

src/test/mir-opt/README.md

@@ -7,13 +7,13 @@ The test format is:
 // END RUST SOURCE
 // START $file_name_of_some_mir_dump_0
 //  $expected_line_0
-// ...
+// (lines or elision)
 // $expected_line_N
 // END $file_name_of_some_mir_dump_0
-// ...
+// (lines or elision)
 // START $file_name_of_some_mir_dump_N
 //  $expected_line_0
-// ...
+// (lines or elision)
 // $expected_line_N
 // END $file_name_of_some_mir_dump_N
 ```
@@ -22,10 +22,15 @@ All the test information is in comments so the test is runnable.
 
 For each $file_name, compiletest expects [$expected_line_0, ...,
 $expected_line_N] to appear in the dumped MIR in order.  Currently it allows
-other non-matched lines before, after and in-between. Note that this includes
+other non-matched lines before and after, but not between $expected_lines,
-lines that end basic blocks or begin new ones; it is good practice
+should you want to skip lines, you must include an elision comment, of the form
-in your tests to include the terminator for each of your basic blocks as an
+(as a regex) `//\s*...\s*`. The lines will be skipped lazily, that is, if there
-internal sanity check guarding against a test like:
+are two identical lines in the output that match the line after the elision
+comment, the first one wil be matched.
+
+Examples:
+
+The following blocks will not match the one after it.
 
 ```
 bb0: {
@@ -35,8 +40,6 @@ bb0: {
 }
 ```
 
-that will inadvertantly pattern-matching against:
-
 ```
 bb0: {
     StorageLive(_1);
@@ -49,6 +52,18 @@ bb1: {
 }
 ```
 
+But this will match the one above,
+
+```
+bb0: {
+    StorageLive(_1);
+    _1 = const true;
+    ...
+    StorageDead(_1);
+    ...
+}
+```
+
 Lines match ignoring whitespace, and the prefix "//" is removed.
 
 It also currently strips trailing comments -- partly because the full file path

src/test/mir-opt/box_expr.rs

@@ -30,7 +30,10 @@ impl Drop for S {
 // END RUST SOURCE
 // START rustc.node4.ElaborateDrops.before.mir
 //     let mut _0: ();
-//     let _1: std::boxed::Box<S>;
+//     scope 1 {
+//         let _1: std::boxed::Box<S>;
+//     }
+//     ...
 //     let mut _2: std::boxed::Box<S>;
 //     let mut _3: ();
 //     let mut _4: std::boxed::Box<S>;

src/test/mir-opt/copy_propagation.rs

@@ -18,17 +18,23 @@ fn main() { }
 // END RUST SOURCE
 // START rustc.node4.CopyPropagation.before.mir
 //  bb0: {
+//      ...
 //      _2 = _1;
+//      ...
 //      _4 = _2;
 //      _3 = _4;
+//      ...
 //      _5 = _3;
 //      _0 = _5;
+//      ...
 //      return;
 //  }
 // END rustc.node4.CopyPropagation.before.mir
 // START rustc.node4.CopyPropagation.after.mir
 //  bb0: {
+//      ...
 //      _0 = _1;
+//      ...
 //      return;
 //  }
 // END rustc.node4.CopyPropagation.after.mir

src/test/mir-opt/deaggregator_test.rs

@@ -23,19 +23,25 @@ fn main() {}
 // END RUST SOURCE
 // START rustc.node13.Deaggregator.before.mir
 // bb0: {
+//     ...
 //     _2 = _1;
+//     ...
 //     _3 = _2;
 //     _0 = Baz { x: _3, y: const 0f32, z: const false };
+//     ...
 //     return;
 // }
 // END rustc.node13.Deaggregator.before.mir
 // START rustc.node13.Deaggregator.after.mir
 // bb0: {
+//     ...
 //     _2 = _1;
+//     ...
 //     _3 = _2;
 //     (_0.0: usize) = _3;
 //     (_0.1: f32) = const 0f32;
 //     (_0.2: bool) = const false;
+//     ...
 //     return;
 // }
 // END rustc.node13.Deaggregator.after.mir

src/test/mir-opt/deaggregator_test_enum.rs

@@ -28,18 +28,26 @@ fn main() {
 // END RUST SOURCE
 // START rustc.node10.Deaggregator.before.mir
 // bb0: {
+//     StorageLive(_2);
 //     _2 = _1;
+//     StorageLive(_3);
 //     _3 = _2;
 //     _0 = Baz::Foo { x: _3 };
+//     StorageDead(_3);
+//     StorageDead(_2);
 //     return;
 // }
 // END rustc.node10.Deaggregator.before.mir
 // START rustc.node10.Deaggregator.after.mir
 // bb0: {
+//     StorageLive(_2);
 //     _2 = _1;
+//     StorageLive(_3);
 //     _3 = _2;
 //     ((_0 as Foo).0: usize) = _3;
 //     discriminant(_0) = 1;
+//     StorageDead(_3);
+//     StorageDead(_2);
 //     return;
 // }
 // END rustc.node10.Deaggregator.after.mir

src/test/mir-opt/deaggregator_test_enum_2.rs

@@ -28,29 +28,35 @@ fn main() {}
 // END RUST SOURCE
 // START rustc.node12.Deaggregator.before.mir
 //  bb1: {
+//      StorageLive(_6);
 //      _6 = _4;
 //      _0 = Foo::A(_6,);
+//      StorageDead(_6);
 //      goto -> bb3;
 //  }
-//
 //  bb2: {
+//      StorageLive(_7);
 //      _7 = _4;
 //      _0 = Foo::B(_7,);
+//      StorageDead(_7);
 //      goto -> bb3;
 //  }
 // END rustc.node12.Deaggregator.before.mir
 // START rustc.node12.Deaggregator.after.mir
 //  bb1: {
+//      StorageLive(_6);
 //      _6 = _4;
 //      ((_0 as A).0: i32) = _6;
 //      discriminant(_0) = 0;
+//      StorageDead(_6);
 //      goto -> bb3;
 //  }
-//
 //  bb2: {
+//      StorageLive(_7);
 //      _7 = _4;
 //      ((_0 as B).0: i32) = _7;
 //      discriminant(_0) = 1;
+//      StorageDead(_7);
 //      goto -> bb3;
 //  }
 // END rustc.node12.Deaggregator.after.mir

src/test/mir-opt/deaggregator_test_multiple.rs

@@ -24,25 +24,35 @@ fn main() { }
 // END RUST SOURCE
 // START rustc.node10.Deaggregator.before.mir
 // bb0: {
+//     ...
 //     _2 = _1;
+//     ...
 //     _4 = _2;
 //     _3 = Foo::A(_4,);
+//     ...
 //     _6 = _2;
 //     _5 = Foo::A(_6,);
+//     ...
 //     _0 = [_3, _5];
+//     ...
 //     return;
 // }
 // END rustc.node10.Deaggregator.before.mir
 // START rustc.node10.Deaggregator.after.mir
 // bb0: {
+//     ...
 //     _2 = _1;
+//     ...
 //     _4 = _2;
 //     ((_3 as A).0: i32) = _4;
 //     discriminant(_3) = 0;
+//     ...
 //     _6 = _2;
 //     ((_5 as A).0: i32) = _6;
 //     discriminant(_5) = 0;
+//     ...
 //     _0 = [_3, _5];
+//     ...
 //     return;
 // }
 // END rustc.node10.Deaggregator.after.mir

src/test/mir-opt/end_region_1.rs

@@ -21,9 +21,11 @@ fn main() {
 // END RUST SOURCE
 // START rustc.node4.SimplifyCfg-qualify-consts.after.mir
 //     let mut _0: ();
+//     ...
 //     let _1: i32;
+//     ...
 //     let _2: &'10_1rs i32;
-//
+//     ...
 //     bb0: {
 //         StorageLive(_1);
 //         _1 = const 3i32;

src/test/mir-opt/end_region_2.rs

@@ -26,11 +26,16 @@ fn main() {
 // END RUST SOURCE
 // START rustc.node4.SimplifyCfg-qualify-consts.after.mir
 //     let mut _0: ();
+//     ...
 //     let _2: bool;
+//     ...
 //     let _3: &'23_1rs bool;
+//     ...
 //     let _7: &'23_3rs bool;
+//     ...
 //     let mut _4: ();
 //     let mut _5: bool;
+//     ...
 //     bb0: {
 //         goto -> bb1;
 //     }
@@ -52,6 +57,7 @@ fn main() {
 //         return;
 //     }
 //     bb3: {
+//         _4 = ();
 //         StorageDead(_5);
 //         StorageLive(_7);
 //         _7 = &'23_3rs _2;

src/test/mir-opt/end_region_3.rs

@@ -27,13 +27,17 @@ fn main() {
 // END RUST SOURCE
 // START rustc.node4.SimplifyCfg-qualify-consts.after.mir
 //     let mut _0: ();
+//     ...
 //     let mut _1: bool;
+//     ...
 //     let _3: &'26_1rs bool;
+//     ...
 //     let _7: &'26_3rs bool;
+//     ...
 //     let mut _2: ();
 //     let mut _4: ();
 //     let mut _5: bool;
-//
+//     let mut _6: !;
 //     bb0: {
 //         StorageLive(_1);
 //         goto -> bb1;

src/test/mir-opt/end_region_4.rs

@@ -31,10 +31,15 @@ fn foo(i: i32) {
 // END RUST SOURCE
 // START rustc.node4.SimplifyCfg-qualify-consts.after.mir
 //     let mut _0: ();
+//     ...
 //     let _1: D;
+//     ...
 //     let _2: i32;
+//     ...
 //     let _3: &'26_2rs i32;
+//     ...
 //     let _6: &'26_4rs i32;
+//     ...
 //     let mut _4: ();
 //     let mut _5: i32;
 //     bb0: {

src/test/mir-opt/end_region_5.rs

@@ -28,8 +28,11 @@ fn foo<F>(f: F) where F: FnOnce() -> i32 {
 // END RUST SOURCE
 // START rustc.node4.SimplifyCfg-qualify-consts.after.mir
 // fn main() -> () {
+//     ...
 //     let mut _0: ();
+//     ...
 //     let _1: D;
+//     ...
 //     let mut _2: ();
 //     let mut _3: [closure@NodeId(18) d:&'14s D];
 //     let mut _4: &'14s D;

src/test/mir-opt/end_region_6.rs

@@ -29,7 +29,9 @@ fn foo<F>(f: F) where F: FnOnce() -> i32 {
 // START rustc.node4.SimplifyCfg-qualify-consts.after.mir
 // fn main() -> () {
 //     let mut _0: ();
+//     ...
 //     let _1: D;
+//     ...
 //     let mut _2: ();
 //     let mut _3: [closure@NodeId(22) d:&'19s D];
 //     let mut _4: &'19s D;
@@ -65,9 +67,10 @@ fn foo<F>(f: F) where F: FnOnce() -> i32 {
 // START rustc.node22.SimplifyCfg-qualify-consts.after.mir
 // fn main::{{closure}}(_1: [closure@NodeId(22) d:&'19s D]) -> i32 {
 //     let mut _0: i32;
+//     ...
 //     let _2: &'15_0rs D;
+//     ...
 //     let mut _3: i32;
-//
 //     bb0: {
 //         StorageLive(_2);
 //         _2 = &'15_0rs (*(_1.0: &'19s D));

src/test/mir-opt/end_region_7.rs

@@ -29,11 +29,12 @@ fn foo<F>(f: F) where F: FnOnce() -> i32 {
 // START rustc.node4.SimplifyCfg-qualify-consts.after.mir
 // fn main() -> () {
 //     let mut _0: ();
+//     ...
 //     let _1: D;
+//     ...
 //     let mut _2: ();
 //     let mut _3: [closure@NodeId(22) d:D];
 //     let mut _4: D;
-//
 //     bb0: {
 //         StorageLive(_1);
 //         _1 = D::{{constructor}}(const 0i32,);
@@ -74,9 +75,10 @@ fn foo<F>(f: F) where F: FnOnce() -> i32 {
 // START rustc.node22.SimplifyCfg-qualify-consts.after.mir
 // fn main::{{closure}}(_1: [closure@NodeId(22) d:D]) -> i32 {
 //     let mut _0: i32;
+//     ...
 //     let _2: &'15_0rs D;
+//     ...
 //     let mut _3: i32;
-//
 //     bb0: {
 //         StorageLive(_2);
 //         _2 = &'15_0rs (_1.0: D);

src/test/mir-opt/end_region_8.rs

@@ -30,8 +30,11 @@ fn foo<F>(f: F) where F: FnOnce() -> i32 {
 // START rustc.node4.SimplifyCfg-qualify-consts.after.mir
 // fn main() -> () {
 //    let mut _0: ();
+//    ...
 //    let _1: D;
+//    ...
 //    let _2: &'21_1rs D;
+//    ...
 //    let mut _3: ();
 //    let mut _4: [closure@NodeId(22) r:&'21_1rs D];
 //    let mut _5: &'21_1rs D;

src/test/mir-opt/end_region_9.rs

@@ -40,15 +40,18 @@ fn main() {
 // START rustc.node4.SimplifyCfg-qualify-consts.after.mir
 // fn main() -> () {
 //     let mut _0: ();
+//     ...
 //     let mut _1: bool;
+//     ...
 //     let _2: i32;
+//     ...
 //     let mut _4: &'33_0rs i32;
+//     ...
 //     let mut _3: ();
 //     let mut _5: !;
 //     let mut _6: ();
 //     let mut _7: bool;
 //     let mut _8: !;
-//
 //     bb0: {
 //        StorageLive(_1);
 //        _1 = const false;
@@ -63,7 +66,6 @@ fn main() {
 //        _7 = _1;
 //        switchInt(_7) -> [0u8: bb3, otherwise: bb2];
 //    }
-//
 //    bb2: {
 //        _0 = ();
 //        StorageDead(_7);
@@ -73,7 +75,6 @@ fn main() {
 //        StorageDead(_1);
 //        return;
 //    }
-//
 //    bb3: {
 //        _4 = &'33_0rs _2;
 //        _6 = ();

src/test/mir-opt/end_region_cyclic.rs

@@ -45,6 +45,7 @@ fn query() -> bool { true }
 //     scope 1 {
 //         let _2: S<'35_0rs>;
 //     }
+//     ...
 //     let mut _1: ();
 //     let mut _3: std::cell::Cell<std::option::Option<&'35_0rs S<'35_0rs>>>;
 //     let mut _4: std::option::Option<&'35_0rs S<'35_0rs>>;

src/test/mir-opt/issue-41110.rs

@@ -35,22 +35,26 @@ impl S {
 // END RUST SOURCE
 // START rustc.node4.ElaborateDrops.after.mir
 //    let mut _0: ();
-//    let _1: ();
+//    scope 1 {
+//        let _1: ();
+//    }
+//    ...
 //    let mut _2: S;
 //    let mut _3: S;
 //    let mut _4: S;
 //    let mut _5: bool;
-//
 //    bb0: {
 // END rustc.node4.ElaborateDrops.after.mir
 // START rustc.node13.ElaborateDrops.after.mir
 //    let mut _0: ();
+//    ...
 //    let _1: S;
+//    ...
 //    let mut _2: S;
+//    ...
 //    let mut _3: ();
 //    let mut _4: S;
 //    let mut _5: S;
 //    let mut _6: bool;
-//
 //    bb0: {
 // END rustc.node13.ElaborateDrops.after.mir

src/test/mir-opt/storage_live_dead_in_statics.rs

@@ -45,56 +45,156 @@ fn main() {
 
 // END RUST SOURCE
 // START rustc.node4.mir_map.0.mir
+//    let mut _0: &'static Foo;
+//    let mut _1: &'static Foo;
+//    let mut _2: Foo;
+//    let mut _3: &'static [(u32, u32)];
+//    let mut _4: &'static [(u32, u32); 42];
+//    let mut _5: &'static [(u32, u32); 42];
+//    let mut _6: [(u32, u32); 42];
+//    let mut _7: (u32, u32);
+//    let mut _8: (u32, u32);
+//    let mut _9: (u32, u32);
+//    let mut _10: (u32, u32);
+//    let mut _11: (u32, u32);
+//    let mut _12: (u32, u32);
+//    let mut _13: (u32, u32);
+//    let mut _14: (u32, u32);
+//    let mut _15: (u32, u32);
+//    let mut _16: (u32, u32);
+//    let mut _17: (u32, u32);
+//    let mut _18: (u32, u32);
+//    let mut _19: (u32, u32);
+//    let mut _20: (u32, u32);
+//    let mut _21: (u32, u32);
+//    let mut _22: (u32, u32);
+//    let mut _23: (u32, u32);
+//    let mut _24: (u32, u32);
+//    let mut _25: (u32, u32);
+//    let mut _26: (u32, u32);
+//    let mut _27: (u32, u32);
+//    let mut _28: (u32, u32);
+//    let mut _29: (u32, u32);
+//    let mut _30: (u32, u32);
+//    let mut _31: (u32, u32);
+//    let mut _32: (u32, u32);
+//    let mut _33: (u32, u32);
+//    let mut _34: (u32, u32);
+//    let mut _35: (u32, u32);
+//    let mut _36: (u32, u32);
+//    let mut _37: (u32, u32);
+//    let mut _38: (u32, u32);
+//    let mut _39: (u32, u32);
+//    let mut _40: (u32, u32);
+//    let mut _41: (u32, u32);
+//    let mut _42: (u32, u32);
+//    let mut _43: (u32, u32);
+//    let mut _44: (u32, u32);
+//    let mut _45: (u32, u32);
+//    let mut _46: (u32, u32);
+//    let mut _47: (u32, u32);
+//    let mut _48: (u32, u32);
 //    bb0: {
-//        _7 = (const 0u32, const 1u32);   // scope 0 at src/test/mir-opt/basic_assignment.rs:29:9: 29:15
+//        StorageLive(_1);
-//        _8 = (const 0u32, const 2u32);   // scope 0 at src/test/mir-opt/basic_assignment.rs:29:17: 29:23
+//        StorageLive(_2);
-//        _9 = (const 0u32, const 3u32);   // scope 0 at src/test/mir-opt/basic_assignment.rs:29:25: 29:31
+//        StorageLive(_3);
-//        _10 = (const 0u32, const 1u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:30:9: 30:15
+//        StorageLive(_4);
-//        _11 = (const 0u32, const 2u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:30:17: 30:23
+//        StorageLive(_5);
-//        _12 = (const 0u32, const 3u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:30:25: 30:31
+//        StorageLive(_6);
-//        _13 = (const 0u32, const 1u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:31:9: 31:15
+//        StorageLive(_7);
-//        _14 = (const 0u32, const 2u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:31:17: 31:23
+//        _7 = (const 0u32, const 1u32);
-//        _15 = (const 0u32, const 3u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:31:25: 31:31
+//        StorageLive(_8);
-//        _16 = (const 0u32, const 1u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:32:9: 32:15
+//        _8 = (const 0u32, const 2u32);
-//        _17 = (const 0u32, const 2u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:32:17: 32:23
+//        StorageLive(_9);
-//        _18 = (const 0u32, const 3u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:32:25: 32:31
+//        _9 = (const 0u32, const 3u32);
-//        _19 = (const 0u32, const 1u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:33:9: 33:15
+//        StorageLive(_10);
-//        _20 = (const 0u32, const 2u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:33:17: 33:23
+//        _10 = (const 0u32, const 1u32);
-//        _21 = (const 0u32, const 3u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:33:25: 33:31
+//        StorageLive(_11);
-//        _22 = (const 0u32, const 1u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:34:9: 34:15
+//        _11 = (const 0u32, const 2u32);
-//        _23 = (const 0u32, const 2u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:34:17: 34:23
+//        StorageLive(_12);
-//        _24 = (const 0u32, const 3u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:34:25: 34:31
+//        _12 = (const 0u32, const 3u32);
-//        _25 = (const 0u32, const 1u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:35:9: 35:15
+//        StorageLive(_13);
-//        _26 = (const 0u32, const 2u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:35:17: 35:23
+//        _13 = (const 0u32, const 1u32);
-//        _27 = (const 0u32, const 3u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:35:25: 35:31
+//        StorageLive(_14);
-//        _28 = (const 0u32, const 1u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:36:9: 36:15
+//        _14 = (const 0u32, const 2u32);
-//        _29 = (const 0u32, const 2u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:36:17: 36:23
+//        StorageLive(_15);
-//        _30 = (const 0u32, const 3u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:36:25: 36:31
+//        _15 = (const 0u32, const 3u32);
-//        _31 = (const 0u32, const 1u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:37:9: 37:15
+//        StorageLive(_16);
-//        _32 = (const 0u32, const 2u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:37:17: 37:23
+//        _16 = (const 0u32, const 1u32);
-//        _33 = (const 0u32, const 3u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:37:25: 37:31
+//        StorageLive(_17);
-//        _34 = (const 0u32, const 1u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:38:9: 38:15
+//        _17 = (const 0u32, const 2u32);
-//        _35 = (const 0u32, const 2u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:38:17: 38:23
+//        StorageLive(_18);
-//        _36 = (const 0u32, const 3u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:38:25: 38:31
+//        _18 = (const 0u32, const 3u32);
-//        _37 = (const 0u32, const 1u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:39:9: 39:15
+//        StorageLive(_19);
-//        _38 = (const 0u32, const 2u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:39:17: 39:23
+//        _19 = (const 0u32, const 1u32);
-//        _39 = (const 0u32, const 3u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:39:25: 39:31
+//        StorageLive(_20);
-//        _40 = (const 0u32, const 1u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:40:9: 40:15
+//        _20 = (const 0u32, const 2u32);
-//        _41 = (const 0u32, const 2u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:40:17: 40:23
+//        StorageLive(_21);
-//        _42 = (const 0u32, const 3u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:40:25: 40:31
+//        _21 = (const 0u32, const 3u32);
-//        _43 = (const 0u32, const 1u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:41:9: 41:15
+//        StorageLive(_22);
-//        _44 = (const 0u32, const 2u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:41:17: 41:23
+//        _22 = (const 0u32, const 1u32);
-//        _45 = (const 0u32, const 3u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:41:25: 41:31
+//        StorageLive(_23);
-//        _46 = (const 0u32, const 1u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:42:9: 42:15
+//        _23 = (const 0u32, const 2u32);
-//        _47 = (const 0u32, const 2u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:42:17: 42:23
+//        StorageLive(_24);
-//        _48 = (const 0u32, const 3u32);  // scope 0 at src/test/mir-opt/basic_assignment.rs:42:25: 42:31
+//        _24 = (const 0u32, const 3u32);
-//        _6 = [_7, _8, _9, _10, _11, _12, _13, _14, _15, _16, _17, _18, _19, _20, _21, _22, _23, _24, _25, _26, _27, _28, _29, _30, _31, _32, _33, _34, _35, _36, _37, _38, _39, _40, _41, _42, _43, _44, _45, _46, _47, _48]; // scope 0 at src/test/mir-opt/basic_assignment.rs:28:12: 43:6
+//        StorageLive(_25);
-//        _5 = &_6;                        // scope 0 at src/test/mir-opt/basic_assignment.rs:28:11: 43:6
+//        _25 = (const 0u32, const 1u32);
-//        _4 = &(*_5);                     // scope 0 at src/test/mir-opt/basic_assignment.rs:28:11: 43:6
+//        StorageLive(_26);
-//        _3 = _4 as &'static [(u32, u32)] (Unsize); // scope 0 at src/test/mir-opt/basic_assignment.rs:28:11: 43:6
+//        _26 = (const 0u32, const 2u32);
-//        _2 = Foo { tup: const "hi", data: _3 }; // scope 0 at src/test/mir-opt/basic_assignment.rs:26:29: 44:2
+//        StorageLive(_27);
-//        _1 = &_2;                        // scope 0 at src/test/mir-opt/basic_assignment.rs:26:28: 44:2
+//        _27 = (const 0u32, const 3u32);
-//        _0 = &(*_1);                     // scope 0 at src/test/mir-opt/basic_assignment.rs:26:28: 44:2
+//        StorageLive(_28);
-//        return;                          // scope 0 at src/test/mir-opt/basic_assignment.rs:26:1: 44:3
+//        _28 = (const 0u32, const 1u32);
+//        StorageLive(_29);
+//        _29 = (const 0u32, const 2u32);
+//        StorageLive(_30);
+//        _30 = (const 0u32, const 3u32);
+//        StorageLive(_31);
+//        _31 = (const 0u32, const 1u32);
+//        StorageLive(_32);
+//        _32 = (const 0u32, const 2u32);
+//        StorageLive(_33);
+//        _33 = (const 0u32, const 3u32);
+//        StorageLive(_34);
+//        _34 = (const 0u32, const 1u32);
+//        StorageLive(_35);
+//        _35 = (const 0u32, const 2u32);
+//        StorageLive(_36);
+//        _36 = (const 0u32, const 3u32);
+//        StorageLive(_37);
+//        _37 = (const 0u32, const 1u32);
+//        StorageLive(_38);
+//        _38 = (const 0u32, const 2u32);
+//        StorageLive(_39);
+//        _39 = (const 0u32, const 3u32);
+//        StorageLive(_40);
+//        _40 = (const 0u32, const 1u32);
+//        StorageLive(_41);
+//        _41 = (const 0u32, const 2u32);
+//        StorageLive(_42);
+//        _42 = (const 0u32, const 3u32);
+//        StorageLive(_43);
+//        _43 = (const 0u32, const 1u32);
+//        StorageLive(_44);
+//        _44 = (const 0u32, const 2u32);
+//        StorageLive(_45);
+//        _45 = (const 0u32, const 3u32);
+//        StorageLive(_46);
+//        _46 = (const 0u32, const 1u32);
+//        StorageLive(_47);
+//        _47 = (const 0u32, const 2u32);
+//        StorageLive(_48);
+//        _48 = (const 0u32, const 3u32);
+//        _6 = [_7, _8, _9, _10, _11, _12, _13, _14, _15, _16, _17, _18, _19, _20, _21, _22, _23, _24, _25, _26, _27, _28, _29, _30, _31, _32, _33, _34, _35, _36, _37, _38, _39, _40, _41, _42, _43, _44, _45, _46, _47, _48];
+//        _5 = &_6;
+//        _4 = &(*_5);
+//        _3 = _4 as &'static [(u32, u32)] (Unsize);
+//        _2 = Foo { tup: const "hi", data: _3 };
+//        _1 = &_2;
+//        _0 = &(*_1);
+//        StorageDead(_1);
+//        StorageDead(_5);
+//        return;
 //    }
+//}
 // END rustc.node4.mir_map.0.mir

src/test/mir-opt/storage_ranges.rs

@@ -38,5 +38,6 @@ fn main() {
 //         _0 = ();
 //         StorageDead(_6);
 //         StorageDead(_1);
+//         return;
 //      }
 // END rustc.node4.TypeckMir.before.mir

src/test/mir-opt/validate_1.rs

@@ -31,12 +31,15 @@ fn main() {
 // START rustc.node12.EraseRegions.after.mir
 //     bb0: {
 //         Validate(Acquire, [_1: &ReFree(DefId { krate: CrateNum(0), index: DefIndex(0:5) => validate_1[8cd8]::{{impl}}[0]::foo[0] }, BrAnon(0)) Test, _2: &ReFree(DefId { krate: CrateNum(0), index: DefIndex(0:5) => validate_1[8cd8]::{{impl}}[0]::foo[0] }, BrAnon(1)) mut i32]);
+//         ...
 //         return;
 //     }
 // END rustc.node12.EraseRegions.after.mir
 // START rustc.node23.EraseRegions.after.mir
 // fn main() -> () {
+//     ...
 //     bb0: {
+//         ...
 //         Validate(Suspend(ReScope(Node(ItemLocalId(10)))), [_1: i32]);
 //         _6 = &ReErased mut _1;
 //         Validate(Acquire, [(*_6): i32/ReScope(Node(ItemLocalId(10)))]);
@@ -50,12 +53,14 @@ fn main() {
 //     bb1: {
 //         Validate(Acquire, [_2: ()]);
 //         EndRegion(ReScope(Node(ItemLocalId(10))));
+//         ...
 //         return;
 //     }
 // }
 // END rustc.node23.EraseRegions.after.mir
 // START rustc.node50.EraseRegions.after.mir
 // fn main::{{closure}}(_1: &ReErased [closure@NodeId(50)], _2: &ReErased mut i32) -> i32 {
+//     ...
 //     bb0: {
 //         Validate(Acquire, [_1: &ReFree(DefId { krate: CrateNum(0), index: DefIndex(1:11) => validate_1[8cd8]::main[0]::{{closure}}[0] }, BrEnv) [closure@NodeId(50)], _2: &ReFree(DefId { krate: CrateNum(0), index: DefIndex(1:11) => validate_1[8cd8]::main[0]::{{closure}}[0] }, BrAnon(1)) mut i32]);
 //         StorageLive(_3);

src/test/mir-opt/validate_2.rs

@@ -18,10 +18,18 @@ fn main() {
 // END RUST SOURCE
 // START rustc.node4.EraseRegions.after.mir
 // fn main() -> () {
+//     ...
 //     bb1: {
+//         Validate(Acquire, [_2: std::boxed::Box<[i32; 3]>]);
 //         Validate(Release, [_2: std::boxed::Box<[i32; 3]>]);
 //         _1 = _2 as std::boxed::Box<[i32]> (Unsize);
 //         Validate(Acquire, [_1: std::boxed::Box<[i32]>]);
+//         StorageDead(_2);
+//         StorageDead(_3);
+//         _0 = ();
+//         Validate(Release, [_1: std::boxed::Box<[i32]>]);
+//         drop(_1) -> bb2;
 //     }
+//     ...
 // }
 // END rustc.node4.EraseRegions.after.mir

src/test/mir-opt/validate_3.rs

@@ -30,8 +30,17 @@ fn main() {
 // END RUST SOURCE
 // START rustc.node16.EraseRegions.after.mir
 // fn main() -> () {
+//     ...
 //     let mut _5: &ReErased i32;
 //     bb0: {
+//         StorageLive(_1);
+//         _1 = Test { x: const 0i32 };
+//         StorageLive(_2);
+//         Validate(Suspend(ReScope(Remainder(BlockRemainder { block: ItemLocalId(19), first_statement_index: 3 }))), [_1: Test]);
+//         _2 = &ReErased _1;
+//         Validate(Acquire, [(*_2): Test/ReScope(Remainder(BlockRemainder { block: ItemLocalId(19), first_statement_index: 3 })) (imm)]);
+//         StorageLive(_4);
+//         StorageLive(_5);
 //         Validate(Suspend(ReScope(Node(ItemLocalId(17)))), [((*_2).0: i32): i32/ReScope(Remainder(BlockRemainder { block: ItemLocalId(19), first_statement_index: 3 })) (imm)]);
 //         _5 = &ReErased ((*_2).0: i32);
 //         Validate(Acquire, [(*_5): i32/ReScope(Node(ItemLocalId(17))) (imm)]);
@@ -42,8 +51,14 @@ fn main() {
 //         _3 = const foo(_4) -> bb1;
 //     }
 //     bb1: {
+//         Validate(Acquire, [_3: ()]);
 //         EndRegion(ReScope(Node(ItemLocalId(17))));
+//         StorageDead(_4);
+//         StorageDead(_5);
+//         _0 = ();
 //         EndRegion(ReScope(Remainder(BlockRemainder { block: ItemLocalId(19), first_statement_index: 3 })));
+//         StorageDead(_2);
+//         StorageDead(_1);
 //         return;
 //     }
 // }

src/test/mir-opt/validate_4.rs

@@ -38,15 +38,18 @@ fn main() {
 // END RUST SOURCE
 // START rustc.node4.EraseRegions.after.mir
 // fn write_42(_1: *mut i32) -> bool {
+//     ...
 //     bb0: {
 //         Validate(Acquire, [_1: *mut i32]);
 //         Validate(Release, [_1: *mut i32]);
+//         ...
 //         return;
 //     }
 // }
 // END rustc.node4.EraseRegions.after.mir
 // START rustc.node22.EraseRegions.after.mir
 // fn write_42::{{closure}}(_1: &ReErased [closure@NodeId(22)], _2: *mut i32) -> () {
+//     ...
 //     bb0: {
 //         Validate(Acquire, [_1: &ReFree(DefId { krate: CrateNum(0), index: DefIndex(1:9) => validate_4[8cd8]::write_42[0]::{{closure}}[0] }, BrEnv) [closure@NodeId(22)], _2: *mut i32]);
 //         Validate(Release, [_1: &ReFree(DefId { krate: CrateNum(0), index: DefIndex(1:9) => validate_4[8cd8]::write_42[0]::{{closure}}[0] }, BrEnv) [closure@NodeId(22)], _2: *mut i32]);
@@ -60,24 +63,30 @@ fn main() {
 // END rustc.node22.EraseRegions.after.mir
 // START rustc.node31.EraseRegions.after.mir
 // fn test(_1: &ReErased mut i32) -> () {
+//     ...
 //     bb0: {
 //         Validate(Acquire, [_1: &ReFree(DefId { krate: CrateNum(0), index: DefIndex(0:4) => validate_4[8cd8]::test[0] }, BrAnon(0)) mut i32]);
 //         Validate(Release, [_1: &ReFree(DefId { krate: CrateNum(0), index: DefIndex(0:4) => validate_4[8cd8]::test[0] }, BrAnon(0)) mut i32]);
+//         ...
 //         _3 = const write_42(_4) -> bb1;
 //     }
 //     bb1: {
 //         Validate(Acquire, [_3: bool]);
 //         Validate(Release, [_3: bool]);
+//         ...
 //     }
 // }
 // END rustc.node31.EraseRegions.after.mir
 // START rustc.node60.EraseRegions.after.mir
 // fn main::{{closure}}(_1: &ReErased [closure@NodeId(60)], _2: &ReErased mut i32) -> bool {
+//     ...
 //     bb0: {
 //         Validate(Acquire, [_1: &ReFree(DefId { krate: CrateNum(0), index: DefIndex(1:10) => validate_4[8cd8]::main[0]::{{closure}}[0] }, BrEnv) [closure@NodeId(60)], _2: &ReFree(DefId { krate: CrateNum(0), index: DefIndex(1:10) => validate_4[8cd8]::main[0]::{{closure}}[0] }, BrAnon(1)) mut i32]);
 //         Validate(Release, [_1: &ReFree(DefId { krate: CrateNum(0), index: DefIndex(1:10) => validate_4[8cd8]::main[0]::{{closure}}[0] }, BrEnv) [closure@NodeId(60)], _2: &ReFree(DefId { krate: CrateNum(0), index: DefIndex(1:10) => validate_4[8cd8]::main[0]::{{closure}}[0] }, BrAnon(1)) mut i32]);
 //         StorageLive(_3);
+//         ...
 //         _0 = const write_42(_4) -> bb1;
 //     }
+//     ...
 // }
 // END rustc.node60.EraseRegions.after.mir

src/test/mir-opt/validate_5.rs

@@ -35,15 +35,19 @@ fn main() {
 // END RUST SOURCE
 // START rustc.node17.EraseRegions.after.mir
 // fn test(_1: &ReErased mut i32) -> () {
+//     ...
 //     bb0: {
 //         Validate(Acquire, [_1: &ReFree(DefId { krate: CrateNum(0), index: DefIndex(0:4) => validate_5[8cd8]::test[0] }, BrAnon(0)) mut i32]);
+//         ...
 //         Validate(Release, [_3: bool, _4: *mut i32]);
 //         _3 = const write_42(_4) -> bb1;
 //     }
+//     ...
 // }
 // END rustc.node17.EraseRegions.after.mir
 // START rustc.node46.EraseRegions.after.mir
 // fn main::{{closure}}(_1: &ReErased [closure@NodeId(46)], _2: &ReErased mut i32) -> bool {
+//     ...
 //     bb0: {
 //         Validate(Acquire, [_1: &ReFree(DefId { krate: CrateNum(0), index: DefIndex(1:9) => validate_5[8cd8]::main[0]::{{closure}}[0] }, BrEnv) [closure@NodeId(46)], _2: &ReFree(DefId { krate: CrateNum(0), index: DefIndex(1:9) => validate_5[8cd8]::main[0]::{{closure}}[0] }, BrAnon(1)) mut i32]);
 //         StorageLive(_3);
@@ -59,5 +63,6 @@ fn main() {
 //         Validate(Release, [_0: bool, _4: *mut i32]);
 //         _0 = const write_42(_4) -> bb1;
 //     }
+//     ...
 // }
 // END rustc.node46.EraseRegions.after.mir

src/tools/compiletest/src/runtest.rs

@@ -25,6 +25,7 @@ use std::collections::HashSet;
 use std::env;
 use std::ffi::OsString;
 use std::fs::{self, File, create_dir_all};
+use std::fmt;
 use std::io::prelude::*;
 use std::io::{self, BufReader};
 use std::path::{Path, PathBuf};
@@ -2228,7 +2229,7 @@ actual:\n\
             let (_, tests_text) = test_file_contents.split_at(idx + "// END_RUST SOURCE".len());
             let tests_text_str = String::from(tests_text);
             let mut curr_test : Option<&str> = None;
-            let mut curr_test_contents = Vec::new();
+            let mut curr_test_contents = vec![ExpectedLine::Elision];
             for l in tests_text_str.lines() {
                 debug!("line: {:?}", l);
                 if l.starts_with("// START ") {
@@ -2242,11 +2243,14 @@ actual:\n\
                     self.compare_mir_test_output(curr_test.unwrap(), &curr_test_contents);
                     curr_test = None;
                     curr_test_contents.clear();
+                    curr_test_contents.push(ExpectedLine::Elision);
                 } else if l.is_empty() {
                     // ignore
+                } else if l.starts_with("//") && l.split_at("//".len()).1.trim() == "..." {
+                    curr_test_contents.push(ExpectedLine::Elision)
                 } else if l.starts_with("// ") {
                     let (_, test_content) = l.split_at("// ".len());
-                    curr_test_contents.push(test_content);
+                    curr_test_contents.push(ExpectedLine::Text(test_content));
                 }
             }
         }
@@ -2264,7 +2268,7 @@ actual:\n\
         }
     }
 
-    fn compare_mir_test_output(&self, test_name: &str, expected_content: &[&str]) {
+    fn compare_mir_test_output(&self, test_name: &str, expected_content: &[ExpectedLine<&str>]) {
         let mut output_file = PathBuf::new();
         output_file.push(self.get_mir_dump_dir());
         output_file.push(test_name);
@@ -2276,38 +2280,77 @@ actual:\n\
         let mut dumped_string = String::new();
         dumped_file.read_to_string(&mut dumped_string).unwrap();
         let mut dumped_lines = dumped_string.lines().filter(|l| !l.is_empty());
-        let mut expected_lines = expected_content.iter().filter(|l| !l.is_empty());
+        let mut expected_lines = expected_content.iter().filter(|&l| {
-
+            if let &ExpectedLine::Text(l) = l {
-        // We expect each non-empty line from expected_content to appear
+                !l.is_empty()
-        // in the dump in order, but there may be extra lines interleaved
+            } else {
-        while let Some(expected_line) = expected_lines.next() {
+                true
-            let e_norm = normalize_mir_line(expected_line);
-            if e_norm.is_empty() {
-                continue;
-            };
-            let mut found = false;
-            while let Some(dumped_line) = dumped_lines.next() {
-                let d_norm = normalize_mir_line(dumped_line);
-                debug!("found: {:?}", d_norm);
-                debug!("expected: {:?}", e_norm);
-                if e_norm == d_norm {
-                    found = true;
-                    break;
-                };
             }
-            if !found {
+        }).peekable();
-                let normalize_all = dumped_string.lines()
+
-                                                 .map(nocomment_mir_line)
+        let compare = |expected_line, dumped_line| {
-                                                 .filter(|l| !l.is_empty())
+            let e_norm = normalize_mir_line(expected_line);
-                                                 .collect::<Vec<_>>()
+            let d_norm = normalize_mir_line(dumped_line);
-                                                 .join("\n");
+            debug!("found: {:?}", d_norm);
-                panic!("ran out of mir dump output to match against.\n\
+            debug!("expected: {:?}", e_norm);
-                        Did not find expected line: {:?}\n\
+            e_norm == d_norm
-                        Expected:\n{}\n\
+        };
-                        Actual:\n{}",
+
-                        expected_line,
+        let error = |expected_line, extra_msg| {
-                        expected_content.join("\n"),
+            let normalize_all = dumped_string.lines()
-                        normalize_all);
+                                             .map(nocomment_mir_line)
+                                             .filter(|l| !l.is_empty())
+                                             .collect::<Vec<_>>()
+                                             .join("\n");
+            let f = |l: &ExpectedLine<_>| match l {
+                &ExpectedLine::Elision => "... (elided)".into(),
+                &ExpectedLine::Text(t) => t
+            };
+            let expected_content = expected_content.iter()
+                                                   .map(|l| f(l))
+                                                   .collect::<Vec<_>>()
+                                                   .join("\n");
+            panic!("Did not find expected line, error: {}\n\
+                   Actual Line: {:?}\n\
+                   Expected:\n{}\n\
+                   Actual:\n{}",
+                   extra_msg,
+                   expected_line,
+                   expected_content,
+                   normalize_all);
+        };
+
+        // We expect each non-empty line to appear consecutively, non-consecutive lines
+        // must be separated by at least one Elision
+        while let Some(dumped_line) = dumped_lines.next() {
+            match expected_lines.next() {
+                Some(&ExpectedLine::Text(expected_line)) =>
+                    if !compare(expected_line, dumped_line) {
+                        error(expected_line,
+                              format!("Mismatch in lines\nExpected Line: {:?}", dumped_line));
+                    },
+                Some(&ExpectedLine::Elision) => {
+                    // skip any number of elisions in a row.
+                    while let Some(&&ExpectedLine::Elision) = expected_lines.peek() {
+                        expected_lines.next();
+                    }
+                    if let Some(&ExpectedLine::Text(expected_line)) = expected_lines.next() {
+                        let mut found = compare(expected_line, dumped_line);
+                        if found {
+                            continue;
+                        }
+                        while let Some(dumped_line) = dumped_lines.next() {
+                            found = compare(expected_line, dumped_line);
+                            if found {
+                                break;
+                            }
+                        }
+                        if !found {
+                            error(expected_line, "ran out of mir dump to match against".into());
+                        }
+                    }
+                },
+                None => {},
             }
         }
     }
@@ -2430,6 +2473,25 @@ enum TargetLocation {
     ThisDirectory(PathBuf),
 }
 
+#[derive(Clone, PartialEq, Eq)]
+enum ExpectedLine<T: AsRef<str>> {
+    Elision,
+    Text(T)
+}
+
+impl<T> fmt::Debug for ExpectedLine<T>
+where
+    T: AsRef<str> + fmt::Debug
+{
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        if let &ExpectedLine::Text(ref t) = self {
+            write!(formatter, "{:?}", t)
+        } else {
+            write!(formatter, "\"...\" (Elision)")
+        }
+    }
+}
+
 fn normalize_mir_line(line: &str) -> String {
     nocomment_mir_line(line).replace(char::is_whitespace, "")
 }