Rust: Miri: rename "undef" -> "uninit"

[RalfJung]

For historic reasons, Miri calls uninitialized memory and the value that you get when reading it "undef(ined)". This is potentially derived from LLVM undef. However, that is actually a misnomer -- Miri's "undef" is much more like LLVM's poison. Also, the docs and user-visible message usually speak about "uninitialized memory/values", and I think that terminology makes much more sense.

We should thus rename all "undef" in Miri to "uninit". In particular, but not limited to:

• InvalidUndefBytes
• ScalarMaybeUndef
• UndefMask

Cc @oli-obk

[sanbox-irl]

@rustbot claim

[hbina]

This will be quite a large change, especially if tests needs to be updated too. And what about the stuff in llvm-project/?

[RalfJung]

I don't think any tests need to be updated, as there should be no user-visible change. And we're not renaming LLVM, just our own Miri types and fields!

If you are grepping for this, only grep in src/librustc_middle/mir/interpret and src/librustc_mir/interpret.

[hbina]

This test will fail

Check compiletest suite=mir-opt mode=mir-opt (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)

running 90 tests
................F............................F................F.F.................FF......
failures:

---- [mir-opt] mir-opt/const_prop/control-flow-simplification.rs stdout ----
51                                                 // + literal: Const { ty: fn(&str) -> ! {std::rt::begin_panic::<&str>}, val: Value(Scalar(<ZST>)) }
52                                                 // ty::Const
53                                                 // + ty: &str
-                                                  // + val: Value(Slice { data: Allocation { bytes: [101, 120, 112, 108, 105, 99, 105, 116, 32, 112, 97, 110, 105, 99], relocations: Relocations(SortedMap { data: [] }), undef_mask: UndefMask { blocks: [16383], len: Size { raw: 14 } }, size: Size { raw: 14 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 14 })
+                                                  // + val: Value(Slice { data: Allocation { bytes: [101, 120, 112, 108, 105, 99, 105, 116, 32, 112, 97, 110, 105, 99], relocations: Relocations(SortedMap { data: [] }), undef_mask: UninitMask { blocks: [16383], len: Size { raw: 14 } }, size: Size { raw: 14 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 14 })
55                                                 // mir::Constant
56                                                 // + span: $SRC_DIR/libstd/macros.rs:LL:COL
-                                                  // + literal: Const { ty: &str, val: Value(Slice { data: Allocation { bytes: [101, 120, 112, 108, 105, 99, 105, 116, 32, 112, 97, 110, 105, 99], relocations: Relocations(SortedMap { data: [] }), undef_mask: UndefMask { blocks: [16383], len: Size { raw: 14 } }, size: Size { raw: 14 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 14 }) }
+                                                  // + literal: Const { ty: &str, val: Value(Slice { data: Allocation { bytes: [101, 120, 112, 108, 105, 99, 105, 116, 32, 112, 97, 110, 105, 99], relocations: Relocations(SortedMap { data: [] }), undef_mask: UninitMask { blocks: [16383], len: Size { raw: 14 } }, size: Size { raw: 14 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 14 }) }
58            }
59        }
60        

thread '[mir-opt] mir-opt/const_prop/control-flow-simplification.rs' panicked at 'Actual MIR output differs from expected MIR output /home/hbinadesk/git/rust/src/test/mir-opt/const_prop/control-flow-simplification/rustc.hello.ConstProp.diff', src/tools/compiletest/src/runtest.rs:3165:25
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

---- [mir-opt] mir-opt/inline/inline-into-box-place.rs stdout ----
24      -                                          // + ty: fn() -> std::vec::Vec<u32> {std::vec::Vec::<u32>::new}
25      -                                          // + val: Value(Scalar(<ZST>))
26      +                                          // + ty: alloc::raw_vec::RawVec<u32>
-       +                                          // + val: Value(ByRef { alloc: Allocation { bytes: [4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], relocations: Relocations(SortedMap { data: [] }), undef_mask: UndefMask { blocks: [65535], len: Size { raw: 16 } }, size: Size { raw: 16 }, align: Align { pow2: 3 }, mutability: Not, extra: () }, offset: Size { raw: 0 } })
+       +                                          // + val: Value(ByRef { alloc: Allocation { bytes: [4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], relocations: Relocations(SortedMap { data: [] }), undef_mask: UninitMask { blocks: [65535], len: Size { raw: 16 } }, size: Size { raw: 16 }, align: Align { pow2: 3 }, mutability: Not, extra: () }, offset: Size { raw: 0 } })
28                                                 // mir::Constant
29      -                                          // + span: $DIR/inline-into-box-place.rs:8:33: 8:41
30      -                                          // + user_ty: UserType(1)

41      -         _0 = const ();                   // bb2[2]: scope 0 at $DIR/inline-into-box-place.rs:7:11: 9:2
42      +                                          // + span: $SRC_DIR/liballoc/vec.rs:LL:COL
43      +                                          // + user_ty: UserType(0)
-       +                                          // + literal: Const { ty: alloc::raw_vec::RawVec<u32>, val: Value(ByRef { alloc: Allocation { bytes: [4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], relocations: Relocations(SortedMap { data: [] }), undef_mask: UndefMask { blocks: [65535], len: Size { raw: 16 } }, size: Size { raw: 16 }, align: Align { pow2: 3 }, mutability: Not, extra: () }, offset: Size { raw: 0 } }) }
+       +                                          // + literal: Const { ty: alloc::raw_vec::RawVec<u32>, val: Value(ByRef { alloc: Allocation { bytes: [4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0], relocations: Relocations(SortedMap { data: [] }), undef_mask: UninitMask { blocks: [65535], len: Size { raw: 16 } }, size: Size { raw: 16 }, align: Align { pow2: 3 }, mutability: Not, extra: () }, offset: Size { raw: 0 } }) }
45      +         ((*_4).1: usize) = const 0usize; // bb0[5]: scope 2 at $SRC_DIR/liballoc/vec.rs:LL:COL
46                                                 // ty::Const
47      +                                          // + ty: usize

thread '[mir-opt] mir-opt/inline/inline-into-box-place.rs' panicked at 'Actual MIR output differs from expected MIR output /home/hbinadesk/git/rust/src/test/mir-opt/inline/inline-into-box-place/64bit/rustc.main.Inline.diff', src/tools/compiletest/src/runtest.rs:3165:25

---- [mir-opt] mir-opt/no-drop-for-inactive-variant.rs stdout ----
32                                               // + literal: Const { ty: fn(&str) -> ! {std::rt::begin_panic::<&str>}, val: Value(Scalar(<ZST>)) }
33                                               // ty::Const
34                                               // + ty: &str
-                                                // + val: Value(Slice { data: Allocation { bytes: [101, 120, 112, 108, 105, 99, 105, 116, 32, 112, 97, 110, 105, 99], relocations: Relocations(SortedMap { data: [] }), undef_mask: UndefMask { blocks: [16383], len: Size { raw: 14 } }, size: Size { raw: 14 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 14 })
+                                                // + val: Value(Slice { data: Allocation { bytes: [101, 120, 112, 108, 105, 99, 105, 116, 32, 112, 97, 110, 105, 99], relocations: Relocations(SortedMap { data: [] }), undef_mask: UninitMask { blocks: [16383], len: Size { raw: 14 } }, size: Size { raw: 14 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 14 })
36                                               // mir::Constant
37                                               // + span: $SRC_DIR/libstd/macros.rs:LL:COL
-                                                // + literal: Const { ty: &str, val: Value(Slice { data: Allocation { bytes: [101, 120, 112, 108, 105, 99, 105, 116, 32, 112, 97, 110, 105, 99], relocations: Relocations(SortedMap { data: [] }), undef_mask: UndefMask { blocks: [16383], len: Size { raw: 14 } }, size: Size { raw: 14 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 14 }) }
+                                                // + literal: Const { ty: &str, val: Value(Slice { data: Allocation { bytes: [101, 120, 112, 108, 105, 99, 105, 116, 32, 112, 97, 110, 105, 99], relocations: Relocations(SortedMap { data: [] }), undef_mask: UninitMask { blocks: [16383], len: Size { raw: 14 } }, size: Size { raw: 14 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 14 }) }
39          }
40
41          bb3: {

thread '[mir-opt] mir-opt/no-drop-for-inactive-variant.rs' panicked at 'Actual MIR output differs from expected MIR output /home/hbinadesk/git/rust/src/test/mir-opt/no-drop-for-inactive-variant/rustc.unwrap.SimplifyCfg-elaborate-drops.after.mir', src/tools/compiletest/src/runtest.rs:3165:25

---- [mir-opt] mir-opt/no-spurious-drop-after-call.rs stdout ----
15              _4 = const "";                   // bb0[4]: scope 0 at $DIR/no-spurious-drop-after-call.rs:9:20: 9:22
16                                               // ty::Const
17                                               // + ty: &str
-                                                // + val: Value(Slice { data: Allocation { bytes: [], relocations: Relocations(SortedMap { data: [] }), undef_mask: UndefMask { blocks: [], len: Size { raw: 0 } }, size: Size { raw: 0 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 0 })
+                                                // + val: Value(Slice { data: Allocation { bytes: [], relocations: Relocations(SortedMap { data: [] }), undef_mask: UninitMask { blocks: [], len: Size { raw: 0 } }, size: Size { raw: 0 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 0 })
19                                               // mir::Constant
20                                               // + span: $DIR/no-spurious-drop-after-call.rs:9:20: 9:22
-                                                // + literal: Const { ty: &str, val: Value(Slice { data: Allocation { bytes: [], relocations: Relocations(SortedMap { data: [] }), undef_mask: UndefMask { blocks: [], len: Size { raw: 0 } }, size: Size { raw: 0 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 0 }) }
+                                                // + literal: Const { ty: &str, val: Value(Slice { data: Allocation { bytes: [], relocations: Relocations(SortedMap { data: [] }), undef_mask: UninitMask { blocks: [], len: Size { raw: 0 } }, size: Size { raw: 0 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 0 }) }
22              _3 = &(*_4);                     // bb0[5]: scope 0 at $DIR/no-spurious-drop-after-call.rs:9:20: 9:22
23              _2 = const <str as std::string::ToString>::to_string(move _3) -> bb2; // bb0[6]: scope 0 at $DIR/no-spurious-drop-after-call.rs:9:20: 9:34
24                                               // ty::Const

thread '[mir-opt] mir-opt/no-spurious-drop-after-call.rs' panicked at 'Actual MIR output differs from expected MIR output /home/hbinadesk/git/rust/src/test/mir-opt/no-spurious-drop-after-call/rustc.main.ElaborateDrops.before.mir', src/tools/compiletest/src/runtest.rs:3165:25

---- [mir-opt] mir-opt/uninhabited_enum_branching.rs stdout ----
27                _5 = const "C";                  // bb1[1]: scope 0 at $DIR/uninhabited_enum_branching.rs:23:21: 23:24
28                                                 // ty::Const
29                                                 // + ty: &str
-                                                  // + val: Value(Slice { data: Allocation { bytes: [67], relocations: Relocations(SortedMap { data: [] }), undef_mask: UndefMask { blocks: [1], len: Size { raw: 1 } }, size: Size { raw: 1 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 1 })
+                                                  // + val: Value(Slice { data: Allocation { bytes: [67], relocations: Relocations(SortedMap { data: [] }), undef_mask: UninitMask { blocks: [1], len: Size { raw: 1 } }, size: Size { raw: 1 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 1 })
31                                                 // mir::Constant
32                                                 // + span: $DIR/uninhabited_enum_branching.rs:23:21: 23:24
-                                                  // + literal: Const { ty: &str, val: Value(Slice { data: Allocation { bytes: [67], relocations: Relocations(SortedMap { data: [] }), undef_mask: UndefMask { blocks: [1], len: Size { raw: 1 } }, size: Size { raw: 1 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 1 }) }
+                                                  // + literal: Const { ty: &str, val: Value(Slice { data: Allocation { bytes: [67], relocations: Relocations(SortedMap { data: [] }), undef_mask: UninitMask { blocks: [1], len: Size { raw: 1 } }, size: Size { raw: 1 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 1 }) }
34                _1 = &(*_5);                     // bb1[2]: scope 0 at $DIR/uninhabited_enum_branching.rs:23:21: 23:24
35                StorageDead(_5);                 // bb1[3]: scope 0 at $DIR/uninhabited_enum_branching.rs:23:23: 23:24
36                goto -> bb4;                     // bb1[4]: scope 0 at $DIR/uninhabited_enum_branching.rs:20:5: 24:6

40                _1 = const "A(Empty)";           // bb2[0]: scope 0 at $DIR/uninhabited_enum_branching.rs:21:24: 21:34
41                                                 // ty::Const
42                                                 // + ty: &str
-                                                  // + val: Value(Slice { data: Allocation { bytes: [65, 40, 69, 109, 112, 116, 121, 41], relocations: Relocations(SortedMap { data: [] }), undef_mask: UndefMask { blocks: [255], len: Size { raw: 8 } }, size: Size { raw: 8 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 8 })
+                                                  // + val: Value(Slice { data: Allocation { bytes: [65, 40, 69, 109, 112, 116, 121, 41], relocations: Relocations(SortedMap { data: [] }), undef_mask: UninitMask { blocks: [255], len: Size { raw: 8 } }, size: Size { raw: 8 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 8 })
44                                                 // mir::Constant
45                                                 // + span: $DIR/uninhabited_enum_branching.rs:21:24: 21:34
-                                                  // + literal: Const { ty: &str, val: Value(Slice { data: Allocation { bytes: [65, 40, 69, 109, 112, 116, 121, 41], relocations: Relocations(SortedMap { data: [] }), undef_mask: UndefMask { blocks: [255], len: Size { raw: 8 } }, size: Size { raw: 8 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 8 }) }
+                                                  // + literal: Const { ty: &str, val: Value(Slice { data: Allocation { bytes: [65, 40, 69, 109, 112, 116, 121, 41], relocations: Relocations(SortedMap { data: [] }), undef_mask: UninitMask { blocks: [255], len: Size { raw: 8 } }, size: Size { raw: 8 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 8 }) }
47                goto -> bb4;                     // bb2[1]: scope 0 at $DIR/uninhabited_enum_branching.rs:20:5: 24:6
48            }
49        

52                _4 = const "B(Empty)";           // bb3[1]: scope 0 at $DIR/uninhabited_enum_branching.rs:22:24: 22:34
53                                                 // ty::Const
54                                                 // + ty: &str
-                                                  // + val: Value(Slice { data: Allocation { bytes: [66, 40, 69, 109, 112, 116, 121, 41], relocations: Relocations(SortedMap { data: [] }), undef_mask: UndefMask { blocks: [255], len: Size { raw: 8 } }, size: Size { raw: 8 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 8 })
+                                                  // + val: Value(Slice { data: Allocation { bytes: [66, 40, 69, 109, 112, 116, 121, 41], relocations: Relocations(SortedMap { data: [] }), undef_mask: UninitMask { blocks: [255], len: Size { raw: 8 } }, size: Size { raw: 8 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 8 })
56                                                 // mir::Constant
57                                                 // + span: $DIR/uninhabited_enum_branching.rs:22:24: 22:34
-                                                  // + literal: Const { ty: &str, val: Value(Slice { data: Allocation { bytes: [66, 40, 69, 109, 112, 116, 121, 41], relocations: Relocations(SortedMap { data: [] }), undef_mask: UndefMask { blocks: [255], len: Size { raw: 8 } }, size: Size { raw: 8 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 8 }) }
+                                                  // + literal: Const { ty: &str, val: Value(Slice { data: Allocation { bytes: [66, 40, 69, 109, 112, 116, 121, 41], relocations: Relocations(SortedMap { data: [] }), undef_mask: UninitMask { blocks: [255], len: Size { raw: 8 } }, size: Size { raw: 8 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 8 }) }
59                _1 = &(*_4);                     // bb3[2]: scope 0 at $DIR/uninhabited_enum_branching.rs:22:24: 22:34
60                StorageDead(_4);                 // bb3[3]: scope 0 at $DIR/uninhabited_enum_branching.rs:22:33: 22:34
61                goto -> bb4;                     // bb3[4]: scope 0 at $DIR/uninhabited_enum_branching.rs:20:5: 24:6

76                _9 = const "E";                  // bb5[1]: scope 0 at $DIR/uninhabited_enum_branching.rs:28:21: 28:24
77                                                 // ty::Const
78                                                 // + ty: &str
-                                                  // + val: Value(Slice { data: Allocation { bytes: [69], relocations: Relocations(SortedMap { data: [] }), undef_mask: UndefMask { blocks: [1], len: Size { raw: 1 } }, size: Size { raw: 1 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 1 })
+                                                  // + val: Value(Slice { data: Allocation { bytes: [69], relocations: Relocations(SortedMap { data: [] }), undef_mask: UninitMask { blocks: [1], len: Size { raw: 1 } }, size: Size { raw: 1 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 1 })
80                                                 // mir::Constant
81                                                 // + span: $DIR/uninhabited_enum_branching.rs:28:21: 28:24
-                                                  // + literal: Const { ty: &str, val: Value(Slice { data: Allocation { bytes: [69], relocations: Relocations(SortedMap { data: [] }), undef_mask: UndefMask { blocks: [1], len: Size { raw: 1 } }, size: Size { raw: 1 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 1 }) }
+                                                  // + literal: Const { ty: &str, val: Value(Slice { data: Allocation { bytes: [69], relocations: Relocations(SortedMap { data: [] }), undef_mask: UninitMask { blocks: [1], len: Size { raw: 1 } }, size: Size { raw: 1 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 1 }) }
83                _6 = &(*_9);                     // bb5[2]: scope 0 at $DIR/uninhabited_enum_branching.rs:28:21: 28:24
84                StorageDead(_9);                 // bb5[3]: scope 0 at $DIR/uninhabited_enum_branching.rs:28:23: 28:24
85                goto -> bb7;                     // bb5[4]: scope 0 at $DIR/uninhabited_enum_branching.rs:26:5: 29:6

89                _6 = const "D";                  // bb6[0]: scope 0 at $DIR/uninhabited_enum_branching.rs:27:21: 27:24
90                                                 // ty::Const
91                                                 // + ty: &str
-                                                  // + val: Value(Slice { data: Allocation { bytes: [68], relocations: Relocations(SortedMap { data: [] }), undef_mask: UndefMask { blocks: [1], len: Size { raw: 1 } }, size: Size { raw: 1 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 1 })
+                                                  // + val: Value(Slice { data: Allocation { bytes: [68], relocations: Relocations(SortedMap { data: [] }), undef_mask: UninitMask { blocks: [1], len: Size { raw: 1 } }, size: Size { raw: 1 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 1 })
93                                                 // mir::Constant
94                                                 // + span: $DIR/uninhabited_enum_branching.rs:27:21: 27:24
-                                                  // + literal: Const { ty: &str, val: Value(Slice { data: Allocation { bytes: [68], relocations: Relocations(SortedMap { data: [] }), undef_mask: UndefMask { blocks: [1], len: Size { raw: 1 } }, size: Size { raw: 1 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 1 }) }
+                                                  // + literal: Const { ty: &str, val: Value(Slice { data: Allocation { bytes: [68], relocations: Relocations(SortedMap { data: [] }), undef_mask: UninitMask { blocks: [1], len: Size { raw: 1 } }, size: Size { raw: 1 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 1 }) }
96                goto -> bb7;                     // bb6[1]: scope 0 at $DIR/uninhabited_enum_branching.rs:26:5: 29:6
97            }
98        

thread '[mir-opt] mir-opt/uninhabited_enum_branching.rs' panicked at 'Actual MIR output differs from expected MIR output /home/hbinadesk/git/rust/src/test/mir-opt/uninhabited_enum_branching/rustc.main.UninhabitedEnumBranching.diff', src/tools/compiletest/src/runtest.rs:3165:25

---- [mir-opt] mir-opt/storage_live_dead_in_statics.rs stdout ----
653             _2 = Foo { tup: const "hi", data: move _3 }; // bb0[94]: scope 0 at $DIR/storage_live_dead_in_statics.rs:5:29: 23:2
654                                              // ty::Const
655                                              // + ty: &str
-                                                // + val: Value(Slice { data: Allocation { bytes: [104, 105], relocations: Relocations(SortedMap { data: [] }), undef_mask: UndefMask { blocks: [3], len: Size { raw: 2 } }, size: Size { raw: 2 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 2 })
+                                                // + val: Value(Slice { data: Allocation { bytes: [104, 105], relocations: Relocations(SortedMap { data: [] }), undef_mask: UninitMask { blocks: [3], len: Size { raw: 2 } }, size: Size { raw: 2 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 2 })
657                                              // mir::Constant
658                                              // + span: $DIR/storage_live_dead_in_statics.rs:6:10: 6:14
-                                                // + literal: Const { ty: &str, val: Value(Slice { data: Allocation { bytes: [104, 105], relocations: Relocations(SortedMap { data: [] }), undef_mask: UndefMask { blocks: [3], len: Size { raw: 2 } }, size: Size { raw: 2 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 2 }) }
+                                                // + literal: Const { ty: &str, val: Value(Slice { data: Allocation { bytes: [104, 105], relocations: Relocations(SortedMap { data: [] }), undef_mask: UninitMask { blocks: [3], len: Size { raw: 2 } }, size: Size { raw: 2 }, align: Align { pow2: 0 }, mutability: Not, extra: () }, start: 0, end: 2 }) }
660             _1 = &_2;                        // bb0[95]: scope 0 at $DIR/storage_live_dead_in_statics.rs:5:28: 23:2
661             _0 = &(*_1);                     // bb0[96]: scope 0 at $DIR/storage_live_dead_in_statics.rs:5:28: 23:2
662             StorageDead(_5);                 // bb0[97]: scope 0 at $DIR/storage_live_dead_in_statics.rs:23:1: 23:2

thread '[mir-opt] mir-opt/storage_live_dead_in_statics.rs' panicked at 'Actual MIR output differs from expected MIR output /home/hbinadesk/git/rust/src/test/mir-opt/storage_live_dead_in_statics/rustc.XXX.mir_map.0.mir', src/tools/compiletest/src/runtest.rs:3165:25


failures:
    [mir-opt] mir-opt/const_prop/control-flow-simplification.rs
    [mir-opt] mir-opt/inline/inline-into-box-place.rs
    [mir-opt] mir-opt/no-drop-for-inactive-variant.rs
    [mir-opt] mir-opt/no-spurious-drop-after-call.rs
    [mir-opt] mir-opt/storage_live_dead_in_statics.rs
    [mir-opt] mir-opt/uninhabited_enum_branching.rs

test result: FAILED. 84 passed; 6 failed; 0 ignored; 0 measured; 0 filtered out

thread 'main' panicked at 'Some tests failed', src/tools/compiletest/src/main.rs:348:22


command did not execute successfully: "/home/hbinadesk/git/rust/build/x86_64-unknown-linux-gnu/stage0-tools-bin/compiletest" "--compile-lib-path" "/home/hbinadesk/git/rust/build/x86_64-unknown-linux-gnu/stage2/lib" "--run-lib-path" "/home/hbinadesk/git/rust/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/x86_64-unknown-linux-gnu/lib" "--rustc-path" "/home/hbinadesk/git/rust/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "--src-base" "/home/hbinadesk/git/rust/src/test/mir-opt" "--build-base" "/home/hbinadesk/git/rust/build/x86_64-unknown-linux-gnu/test/mir-opt" "--stage-id" "stage2-x86_64-unknown-linux-gnu" "--mode" "mir-opt" "--target" "x86_64-unknown-linux-gnu" "--host" "x86_64-unknown-linux-gnu" "--llvm-filecheck" "/home/hbinadesk/git/rust/build/x86_64-unknown-linux-gnu/llvm/build/bin/FileCheck" "--nodejs" "/usr/bin/node" "--host-rustcflags" "-Crpath -O -Cdebuginfo=0 -Zunstable-options  -Lnative=/home/hbinadesk/git/rust/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--target-rustcflags" "-Crpath -O -Cdebuginfo=0 -Zunstable-options  -Lnative=/home/hbinadesk/git/rust/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--docck-python" "/usr/bin/python" "--lldb-python" "/usr/bin/python" "--gdb" "/usr/bin/gdb" "--lldb-version" "lldb version 6.0.0\n" "--lldb-python-dir" "/usr/lib/x86_64-linux-gnu/python2.7/site-packages" "--quiet" "--llvm-version" "9.0.1-rust-dev" "--cc" "" "--cxx" "" "--cflags" "" "--llvm-components" "" "--adb-path" "adb" "--adb-test-dir" "/data/tmp/work" "--android-cross-path" ""
expected success, got: exit code: 101


failed to run: /home/hbinadesk/git/rust/build/bootstrap/debug/bootstrap test
Build completed unsuccessfully in 0:50:34

[RalfJung]

@hbina thanks a lot for working on this!
I responded in your PR.

[RalfJung]

Another type we will want to rename in a second batch is AllocationDefinedness. Also there are probably plenty of comments still left to be updated.

[Dylan-DPC]

@hbina just a small note: before working on an issue, please check if someone else has claimed it (if it is assigned to rustbot) :)

[RalfJung]

All right, the first round of renames landed. :) Thanks @hbina!

For the second round, here are some more names in librustc_middle/mir/interpret that should be changed:

• ScalarMaybeUninit::not_undef -> ... hm @oli-obk how do we call this, not_uninit is a bit weird. what about init? check_init?
• Allocation::undef -> uninit
• check_defined_and_ptr -> check_init_and_ptr
• is_defined+check_defined -> is_init/check_init
• mark_definedness -> mark_init
• AllocationDefinedness -> ... this is really the same information as InitMask but more compact for copying right? So maybe InitMaskCompact or InitMaskCompressed or so?
• all_bytes_undef -> all_bytes_uninit
• mark_compressed_undef_range -> mark_compressed_init_range (or "compact" if that's what we are going for above)

[oli-obk]

* `not_uninit` is a bit weird. what about `init`? `check_init`?

yea, check_init sounds good. not_undef always was a bit odd

* `is_defined`+`check_defined` -> `is_init`/`check_init`

this makes me wonder whether it should be is_initialized and check_initialized

* `all_bytes_undef` -> `all_bytes_uninit`

any_bytes_init?

[RalfJung]

this makes me wonder whether it should be is_initialized and check_initialized

initialized is very long and unint has a lot of precedence, so I think I'd prefer the short version.

any_bytes_init?

I guess it depends on the caller which naming is more apt. But I feel like an "all" statement is intuitively clearer than an "any" statement.

[pnadon]

Hello,

I saw that this issue was still open but the last post was 2 months ago, is there a chance I could try and help out?

[Dylan-DPC]

@pnadon sure.. 2 months is a short timeframe in rust's perspective :D

[pnadon]

@Dylan-DPC Ok sounds good,

From what I understand from the comments above, the two directories I should look in are

src/librustc_middle/mir/interpret
and
src/librustc_mir/interpret

And the goal would be to rename parts of names with "undef" in them to "uninit", along with some changes with "def" to "init". Is this correct?

[RalfJung]

@pnadon thanks for chiming in! Yes, that sounds right. More specifically, as far as I know, the list at https://github.com/rust-lang/rust/issues/71193#issuecomment-626128359 is still up-to-date. Post in this thread or open a topic on Rust's Zulip if you need any help; my availability is spotty until mid next week but there'll always be someone around. :)

[pnadon]

this makes me wonder whether it should be is_initialized and check_initialized

initialized is very long and unint has a lot of precedence, so I think I'd prefer the short version.

any_bytes_init?

I guess it depends on the caller which naming is more apt. But I feel like an "all" statement is intuitively clearer than an "any" statement.

no_bytes_init? I assumed it would be synonymous with "all_bytes_uninit"

[pnadon]

All right, the first round of renames landed. :) Thanks @hbina!

For the second round, here are some more names in librustc_middle/mir/interpret that should be changed:

* `ScalarMaybeUninit::not_undef` -> ... hm @oli-obk  how do we call this, `not_uninit` is a bit weird. what about `init`? `check_init`?

* `Allocation::undef` -> `uninit`

* `check_defined_and_ptr` -> `check_init_and_ptr`

* `is_defined`+`check_defined` -> `is_init`/`check_init`

* `mark_definedness` -> `mark_init`

I have made commits for the above changes, however I would like to wait until everyone agrees on the new names for below:

* `AllocationDefinedness` -> ... this is really the same information as `InitMask` but more compact for copying right? So maybe `InitMaskCompact` or `InitMaskCompressed` or so?

I think InitMaskCompressed would be more of a mouthful but also more accurate based on the definition here, so I agree with the latter.

* `all_bytes_undef` -> `all_bytes_uninit`

As per my previous comment, no_bytes_init?

* `mark_compressed_undef_range` -> `mark_compressed_init_range` (or "compact" if that's what we are going for above)

I agree.

[RalfJung]

I like no_bytes_init.

[pnadon]

I have also found:

• inspect_with_undef_and_ptr_outside_interpreter (line 160)
• get_bytes_with_undef_and_ptr (247)
• allow_ptr_and_undef parameter for check_bytes (312)
• compress_undef_range (597)
• and the undef_end variable (781)
  for src/librustc_middle/mir/interpret, all inside of allocation.rs. Should these be changed as well?

There are also many comments which should be changed, many of them refer to "definedness", which I am not sure what to replace with.

[RalfJung]

Yes, those all should become "uninit" I think.

For consistency maybe allow_ptr_and_undef should become allow_uninit_and_ptr.

[pnadon]

Yes, those all should become "uninit" I think.

For consistency maybe allow_ptr_and_undef should become allow_uninit_and_ptr.

Sounds good. Should I go ahead and implement those changes?

I will also look around for any comments etc. that we may have missed and make sure that we've got them all.

[RalfJung]

@pnadon yes please do. :)

[pnadon]

I've done the initial renames, however outside of the two directories (src/librustc_middle/mir/interpret and src/librustc_mir/interpret) we had initially planned to work within, there are changes made in the following files:

1. src/librustc_codegen_llvm/consts.rs, lines {44, 52, 77, 455, and 483}, which all contain the inspect_with_undef_and_ptr_outside_interpreter function and thus must be renamed.
2. src/tools/clippy/clippy_lints/src/consts.rs, lines {520, 533, 547}, which also contain the inspect_with_undef_and_ptr_outside_interpreter function and thus must be renamed.

The former seems to be a fairly straightforward change, I just want to confirm that it's ok. As for the latter, since it is a submodule, I believe I will have to create a pull request for clippy with those changes.

Once these issues are resolved, I will look into making the approapriate changes within the Miri repo.

[oli-obk]

clippy is not a submodule anymore. You can do these renames either here or in clippy as you prefer

[pnadon]

clippy is not a submodule anymore. You can do these renames either here or in clippy as you prefer

Sounds good!

[pnadon]

I have also found:

* `inspect_with_undef_and_ptr_outside_interpreter` (line 160)

* `get_bytes_with_undef_and_ptr` (247)

* `allow_ptr_and_undef` parameter for `check_bytes` (312)

* `compress_undef_range` (597)

* and the `undef_end` variable (781)
  for `src/librustc_middle/mir/interpret`, all inside of allocation.rs. Should these be changed as well?

There are also many comments which should be changed, many of them refer to "definedness", which I am not sure what to replace with.

Upon further inspection it does not seem as though there are any references to the above functions within the Miri repository.

[RalfJung]

Upon further inspection it does not seem as though there are any references to the above functions within the Miri repository.

That's great, it makes the rename easier. :)
Does your list contain all uses of "undef" in src/librustc_middle/mir/interpret and src/librustc_mir/interpret?

There are also many comments which should be changed, many of them refer to "definedness", which I am not sure what to replace with.

"initializedness" is awkward, so they should probably be reworded. But from what I can see there is just one occurrence of "definedness" left in the Miri folders:

src/librustc_middle/mir/interpret/allocation.rs
636-        size: Size,
637-        repeat: u64,
638-    ) {
639:        // An optimization where we can just overwrite an entire range of definedness bits if
640-        // they are going to be uniformly `1` or `0`.
641-        if defined.ranges.len() <= 1 {
642-            self.init_mask.set_range_inbounds(

I'd make this "an entire range of initialization bits" or so.

[pnadon]

Upon further inspection it does not seem as though there are any references to the above functions within the Miri repository.

That's great, it makes the rename easier. :)
Does your list contain all uses of "undef" in src/librustc_middle/mir/interpret and src/librustc_mir/interpret?

There are also many comments which should be changed, many of them refer to "definedness", which I am not sure what to replace with.

"initializedness" is awkward, so they should probably be reworded. But from what I can see there is just one occurrence of "definedness" left in the Miri folders:

src/librustc_middle/mir/interpret/allocation.rs
636-        size: Size,
637-        repeat: u64,
638-    ) {
639:        // An optimization where we can just overwrite an entire range of definedness bits if
640-        // they are going to be uniformly `1` or `0`.
641-        if defined.ranges.len() <= 1 {
642-            self.init_mask.set_range_inbounds(

I'd make this "an entire range of initialization bits" or so.

Thank you for catching that, I'll look into it!

[pnadon]

Miri builds successfully, I have double-checked my search through both directories and all references to "undef" refer to "undefined behavior" which (unless I'm wrong) is unrelated.

I have also changed the last remaining "definedness" to the recommended change.

If this all looks good I will open a PR with my changes.

[RalfJung]

It sounds great, please open a PR. :)

[RalfJung]

@pnadon fixed the remaining ones in https://github.com/rust-lang/rust/pull/75226, I think we are done. Thanks a lot to everyone involved. :)