Basic block predecessors in mir textual representation

Similiar to how LLVM-IR includes `; preds = %bb1` in its textual output. Makes it a bit nicer to read mir dumps.
rust-lang · Feb 19, 2022 · 8d48733 · 8d48733
1 parent e08d569
commit 8d48733
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Showing 307 changed files with 1,390 additions and 1,353 deletions.
diff --git a/compiler/rustc_middle/src/mir/pretty.rs b/compiler/rustc_middle/src/mir/pretty.rs
@@ -351,7 +351,9 @@ where
 
     // Basic block label at the top.
     let cleanup_text = if data.is_cleanup { " (cleanup)" } else { "" };
-    writeln!(w, "{}{:?}{}: {{", INDENT, block, cleanup_text)?;
+    let indented_body = format!("{}{:?}{}: {{", INDENT, block, cleanup_text);
+    let predecessors = &body.predecessors()[block];
+    writeln!(w, "{:A$} // preds: {:?}", indented_body, predecessors, A = ALIGN)?;
 
     // List of statements in the middle.
     let mut current_location = Location { block, statement_index: 0 };

diff --git a/src/test/mir-opt/76803_regression.encode.SimplifyBranchSame.diff b/src/test/mir-opt/76803_regression.encode.SimplifyBranchSame.diff
@@ -6,22 +6,22 @@
       let mut _0: Type;                    // return place in scope 0 at $DIR/76803_regression.rs:10:27: 10:31
       let mut _2: isize;                   // in scope 0 at $DIR/76803_regression.rs:12:9: 12:16
 
-      bb0: {
+      bb0: {                               // preds: []
           _2 = discriminant(_1);           // scope 0 at $DIR/76803_regression.rs:11:11: 11:12
           switchInt(move _2) -> [0_isize: bb2, otherwise: bb1]; // scope 0 at $DIR/76803_regression.rs:11:5: 11:12
       }
 
-      bb1: {
+      bb1: {                               // preds: [bb0]
           _0 = move _1;                    // scope 0 at $DIR/76803_regression.rs:13:14: 13:15
           goto -> bb3;                     // scope 0 at $DIR/76803_regression.rs:13:14: 13:15
       }
 
-      bb2: {
+      bb2: {                               // preds: [bb0]
           discriminant(_0) = 1;            // scope 0 at $DIR/76803_regression.rs:12:20: 12:27
           goto -> bb3;                     // scope 0 at $DIR/76803_regression.rs:12:20: 12:27
       }
 
-      bb3: {
+      bb3: {                               // preds: [bb1, bb2]
           return;                          // scope 0 at $DIR/76803_regression.rs:15:2: 15:2
       }
   }

diff --git a/src/test/mir-opt/address_of.address_of_reborrow.SimplifyCfg-initial.after.mir b/src/test/mir-opt/address_of.address_of_reborrow.SimplifyCfg-initial.after.mir
@@ -125,7 +125,7 @@ fn address_of_reborrow() -> () {
         }
     }
 
-    bb0: {
+    bb0: {                               // preds: []
         StorageLive(_1);                 // scope 0 at $DIR/address-of.rs:4:9: 4:10
         StorageLive(_2);                 // scope 0 at $DIR/address-of.rs:4:14: 4:21
         _2 = [const 0_i32; 10];          // scope 0 at $DIR/address-of.rs:4:14: 4:21

diff --git a/src/test/mir-opt/address_of.borrow_and_cast.SimplifyCfg-initial.after.mir b/src/test/mir-opt/address_of.borrow_and_cast.SimplifyCfg-initial.after.mir
@@ -19,7 +19,7 @@ fn borrow_and_cast(_1: i32) -> () {
         }
     }
 
-    bb0: {
+    bb0: {                               // preds: []
         StorageLive(_2);                 // scope 0 at $DIR/address-of.rs:42:9: 42:10
         StorageLive(_3);                 // scope 0 at $DIR/address-of.rs:42:13: 42:15
         _3 = &_1;                        // scope 0 at $DIR/address-of.rs:42:13: 42:15

diff --git a/src/test/mir-opt/array_index_is_temporary.main.SimplifyCfg-elaborate-drops.after.32bit.mir b/src/test/mir-opt/array_index_is_temporary.main.SimplifyCfg-elaborate-drops.after.32bit.mir
@@ -23,7 +23,7 @@ fn main() -> () {
         }
     }
 
-    bb0: {
+    bb0: {                               // preds: []
         StorageLive(_1);                 // scope 0 at $DIR/array-index-is-temporary.rs:13:9: 13:14
         _1 = [const 42_u32, const 43_u32, const 44_u32]; // scope 0 at $DIR/array-index-is-temporary.rs:13:17: 13:29
         StorageLive(_2);                 // scope 1 at $DIR/array-index-is-temporary.rs:14:9: 14:14
@@ -42,7 +42,7 @@ fn main() -> () {
                                          // + literal: Const { ty: unsafe fn(*mut usize) -> u32 {foo}, val: Value(Scalar(<ZST>)) }
     }
 
-    bb1: {
+    bb1: {                               // preds: [bb0]
         StorageDead(_6);                 // scope 4 at $DIR/array-index-is-temporary.rs:16:26: 16:27
         StorageLive(_7);                 // scope 3 at $DIR/array-index-is-temporary.rs:16:7: 16:8
         _7 = _2;                         // scope 3 at $DIR/array-index-is-temporary.rs:16:7: 16:8
@@ -51,7 +51,7 @@ fn main() -> () {
         assert(move _9, "index out of bounds: the length is {} but the index is {}", move _8, _7) -> bb2; // scope 3 at $DIR/array-index-is-temporary.rs:16:5: 16:9
     }
 
-    bb2: {
+    bb2: {                               // preds: [bb1]
         _1[_7] = move _5;                // scope 3 at $DIR/array-index-is-temporary.rs:16:5: 16:29
         StorageDead(_5);                 // scope 3 at $DIR/array-index-is-temporary.rs:16:28: 16:29
         StorageDead(_7);                 // scope 3 at $DIR/array-index-is-temporary.rs:16:29: 16:30

diff --git a/src/test/mir-opt/array_index_is_temporary.main.SimplifyCfg-elaborate-drops.after.64bit.mir b/src/test/mir-opt/array_index_is_temporary.main.SimplifyCfg-elaborate-drops.after.64bit.mir
@@ -23,7 +23,7 @@ fn main() -> () {
         }
     }
 
-    bb0: {
+    bb0: {                               // preds: []
         StorageLive(_1);                 // scope 0 at $DIR/array-index-is-temporary.rs:13:9: 13:14
         _1 = [const 42_u32, const 43_u32, const 44_u32]; // scope 0 at $DIR/array-index-is-temporary.rs:13:17: 13:29
         StorageLive(_2);                 // scope 1 at $DIR/array-index-is-temporary.rs:14:9: 14:14
@@ -42,7 +42,7 @@ fn main() -> () {
                                          // + literal: Const { ty: unsafe fn(*mut usize) -> u32 {foo}, val: Value(Scalar(<ZST>)) }
     }
 
-    bb1: {
+    bb1: {                               // preds: [bb0]
         StorageDead(_6);                 // scope 4 at $DIR/array-index-is-temporary.rs:16:26: 16:27
         StorageLive(_7);                 // scope 3 at $DIR/array-index-is-temporary.rs:16:7: 16:8
         _7 = _2;                         // scope 3 at $DIR/array-index-is-temporary.rs:16:7: 16:8
@@ -51,7 +51,7 @@ fn main() -> () {
         assert(move _9, "index out of bounds: the length is {} but the index is {}", move _8, _7) -> bb2; // scope 3 at $DIR/array-index-is-temporary.rs:16:5: 16:9
     }
 
-    bb2: {
+    bb2: {                               // preds: [bb1]
         _1[_7] = move _5;                // scope 3 at $DIR/array-index-is-temporary.rs:16:5: 16:29
         StorageDead(_5);                 // scope 3 at $DIR/array-index-is-temporary.rs:16:28: 16:29
         StorageDead(_7);                 // scope 3 at $DIR/array-index-is-temporary.rs:16:29: 16:30

diff --git a/src/test/mir-opt/basic_assignment.main.SimplifyCfg-initial.after.mir b/src/test/mir-opt/basic_assignment.main.SimplifyCfg-initial.after.mir
@@ -25,7 +25,7 @@ fn main() -> () {
         }
     }
 
-    bb0: {
+    bb0: {                               // preds: []
         StorageLive(_1);                 // scope 0 at $DIR/basic_assignment.rs:11:9: 11:17
         _1 = const false;                // scope 0 at $DIR/basic_assignment.rs:11:20: 11:25
         FakeRead(ForLet(None), _1);      // scope 0 at $DIR/basic_assignment.rs:11:9: 11:17
@@ -44,41 +44,41 @@ fn main() -> () {
         replace(_5 <- move _6) -> [return: bb1, unwind: bb5]; // scope 4 at $DIR/basic_assignment.rs:23:5: 23:11
     }
 
-    bb1: {
+    bb1: {                               // preds: [bb0]
         drop(_6) -> [return: bb2, unwind: bb6]; // scope 4 at $DIR/basic_assignment.rs:23:19: 23:20
     }
 
-    bb2: {
+    bb2: {                               // preds: [bb1]
         StorageDead(_6);                 // scope 4 at $DIR/basic_assignment.rs:23:19: 23:20
         _0 = const ();                   // scope 0 at $DIR/basic_assignment.rs:10:11: 24:2
         drop(_5) -> [return: bb3, unwind: bb7]; // scope 3 at $DIR/basic_assignment.rs:24:1: 24:2
     }
 
-    bb3: {
+    bb3: {                               // preds: [bb2]
         StorageDead(_5);                 // scope 3 at $DIR/basic_assignment.rs:24:1: 24:2
         drop(_4) -> [return: bb4, unwind: bb8]; // scope 2 at $DIR/basic_assignment.rs:24:1: 24:2
     }
 
-    bb4: {
+    bb4: {                               // preds: [bb3]
         StorageDead(_4);                 // scope 2 at $DIR/basic_assignment.rs:24:1: 24:2
         StorageDead(_2);                 // scope 1 at $DIR/basic_assignment.rs:24:1: 24:2
         StorageDead(_1);                 // scope 0 at $DIR/basic_assignment.rs:24:1: 24:2
         return;                          // scope 0 at $DIR/basic_assignment.rs:24:2: 24:2
     }
 
-    bb5 (cleanup): {
+    bb5 (cleanup): {                     // preds: [bb0]
         drop(_6) -> bb6;                 // scope 4 at $DIR/basic_assignment.rs:23:19: 23:20
     }
 
-    bb6 (cleanup): {
+    bb6 (cleanup): {                     // preds: [bb1, bb5]
         drop(_5) -> bb7;                 // scope 3 at $DIR/basic_assignment.rs:24:1: 24:2
     }
 
-    bb7 (cleanup): {
+    bb7 (cleanup): {                     // preds: [bb2, bb6]
         drop(_4) -> bb8;                 // scope 2 at $DIR/basic_assignment.rs:24:1: 24:2
     }
 
-    bb8 (cleanup): {
+    bb8 (cleanup): {                     // preds: [bb3, bb7]
         resume;                          // scope 0 at $DIR/basic_assignment.rs:10:1: 24:2
     }
 }
diff --git a/src/test/mir-opt/bool_compare.opt1.InstCombine.diff b/src/test/mir-opt/bool_compare.opt1.InstCombine.diff
@@ -7,7 +7,7 @@
       let mut _2: bool;                    // in scope 0 at $DIR/bool_compare.rs:3:8: 3:17
       let mut _3: bool;                    // in scope 0 at $DIR/bool_compare.rs:3:8: 3:9
 
-      bb0: {
+      bb0: {                               // preds: []
           StorageLive(_2);                 // scope 0 at $DIR/bool_compare.rs:3:8: 3:17
           StorageLive(_3);                 // scope 0 at $DIR/bool_compare.rs:3:8: 3:9
           _3 = _1;                         // scope 0 at $DIR/bool_compare.rs:3:8: 3:9
@@ -17,17 +17,17 @@
           switchInt(move _2) -> [false: bb2, otherwise: bb1]; // scope 0 at $DIR/bool_compare.rs:3:8: 3:17
       }
 
-      bb1: {
+      bb1: {                               // preds: [bb0]
           _0 = const 0_u32;                // scope 0 at $DIR/bool_compare.rs:3:20: 3:21
           goto -> bb3;                     // scope 0 at $DIR/bool_compare.rs:3:5: 3:34
       }
 
-      bb2: {
+      bb2: {                               // preds: [bb0]
           _0 = const 1_u32;                // scope 0 at $DIR/bool_compare.rs:3:31: 3:32
           goto -> bb3;                     // scope 0 at $DIR/bool_compare.rs:3:5: 3:34
       }
 
-      bb3: {
+      bb3: {                               // preds: [bb1, bb2]
           StorageDead(_2);                 // scope 0 at $DIR/bool_compare.rs:3:33: 3:34
           return;                          // scope 0 at $DIR/bool_compare.rs:4:2: 4:2
       }

diff --git a/src/test/mir-opt/bool_compare.opt2.InstCombine.diff b/src/test/mir-opt/bool_compare.opt2.InstCombine.diff
@@ -7,7 +7,7 @@
       let mut _2: bool;                    // in scope 0 at $DIR/bool_compare.rs:8:8: 8:17
       let mut _3: bool;                    // in scope 0 at $DIR/bool_compare.rs:8:16: 8:17
 
-      bb0: {
+      bb0: {                               // preds: []
           StorageLive(_2);                 // scope 0 at $DIR/bool_compare.rs:8:8: 8:17
           StorageLive(_3);                 // scope 0 at $DIR/bool_compare.rs:8:16: 8:17
           _3 = _1;                         // scope 0 at $DIR/bool_compare.rs:8:16: 8:17
@@ -17,17 +17,17 @@
           switchInt(move _2) -> [false: bb2, otherwise: bb1]; // scope 0 at $DIR/bool_compare.rs:8:8: 8:17
       }
 
-      bb1: {
+      bb1: {                               // preds: [bb0]
           _0 = const 0_u32;                // scope 0 at $DIR/bool_compare.rs:8:20: 8:21
           goto -> bb3;                     // scope 0 at $DIR/bool_compare.rs:8:5: 8:34
       }
 
-      bb2: {
+      bb2: {                               // preds: [bb0]
           _0 = const 1_u32;                // scope 0 at $DIR/bool_compare.rs:8:31: 8:32
           goto -> bb3;                     // scope 0 at $DIR/bool_compare.rs:8:5: 8:34
       }
 
-      bb3: {
+      bb3: {                               // preds: [bb1, bb2]
           StorageDead(_2);                 // scope 0 at $DIR/bool_compare.rs:8:33: 8:34
           return;                          // scope 0 at $DIR/bool_compare.rs:9:2: 9:2
       }

diff --git a/src/test/mir-opt/bool_compare.opt3.InstCombine.diff b/src/test/mir-opt/bool_compare.opt3.InstCombine.diff
@@ -7,7 +7,7 @@
       let mut _2: bool;                    // in scope 0 at $DIR/bool_compare.rs:13:8: 13:18
       let mut _3: bool;                    // in scope 0 at $DIR/bool_compare.rs:13:8: 13:9
 
-      bb0: {
+      bb0: {                               // preds: []
           StorageLive(_2);                 // scope 0 at $DIR/bool_compare.rs:13:8: 13:18
           StorageLive(_3);                 // scope 0 at $DIR/bool_compare.rs:13:8: 13:9
           _3 = _1;                         // scope 0 at $DIR/bool_compare.rs:13:8: 13:9
@@ -17,17 +17,17 @@
           switchInt(move _2) -> [false: bb2, otherwise: bb1]; // scope 0 at $DIR/bool_compare.rs:13:8: 13:18
       }
 
-      bb1: {
+      bb1: {                               // preds: [bb0]
           _0 = const 0_u32;                // scope 0 at $DIR/bool_compare.rs:13:21: 13:22
           goto -> bb3;                     // scope 0 at $DIR/bool_compare.rs:13:5: 13:35
       }
 
-      bb2: {
+      bb2: {                               // preds: [bb0]
           _0 = const 1_u32;                // scope 0 at $DIR/bool_compare.rs:13:32: 13:33
           goto -> bb3;                     // scope 0 at $DIR/bool_compare.rs:13:5: 13:35
       }
 
-      bb3: {
+      bb3: {                               // preds: [bb1, bb2]
           StorageDead(_2);                 // scope 0 at $DIR/bool_compare.rs:13:34: 13:35
           return;                          // scope 0 at $DIR/bool_compare.rs:14:2: 14:2
       }

diff --git a/src/test/mir-opt/bool_compare.opt4.InstCombine.diff b/src/test/mir-opt/bool_compare.opt4.InstCombine.diff
@@ -7,7 +7,7 @@
       let mut _2: bool;                    // in scope 0 at $DIR/bool_compare.rs:18:8: 18:18
       let mut _3: bool;                    // in scope 0 at $DIR/bool_compare.rs:18:17: 18:18
 
-      bb0: {
+      bb0: {                               // preds: []
           StorageLive(_2);                 // scope 0 at $DIR/bool_compare.rs:18:8: 18:18
           StorageLive(_3);                 // scope 0 at $DIR/bool_compare.rs:18:17: 18:18
           _3 = _1;                         // scope 0 at $DIR/bool_compare.rs:18:17: 18:18
@@ -17,17 +17,17 @@
           switchInt(move _2) -> [false: bb2, otherwise: bb1]; // scope 0 at $DIR/bool_compare.rs:18:8: 18:18
       }
 
-      bb1: {
+      bb1: {                               // preds: [bb0]
           _0 = const 0_u32;                // scope 0 at $DIR/bool_compare.rs:18:21: 18:22
           goto -> bb3;                     // scope 0 at $DIR/bool_compare.rs:18:5: 18:35
       }
 
-      bb2: {
+      bb2: {                               // preds: [bb0]
           _0 = const 1_u32;                // scope 0 at $DIR/bool_compare.rs:18:32: 18:33
           goto -> bb3;                     // scope 0 at $DIR/bool_compare.rs:18:5: 18:35
       }
 
-      bb3: {
+      bb3: {                               // preds: [bb1, bb2]
           StorageDead(_2);                 // scope 0 at $DIR/bool_compare.rs:18:34: 18:35
           return;                          // scope 0 at $DIR/bool_compare.rs:19:2: 19:2
       }

diff --git a/src/test/mir-opt/box_expr.main.ElaborateDrops.before.mir b/src/test/mir-opt/box_expr.main.ElaborateDrops.before.mir
@@ -15,7 +15,7 @@ fn main() -> () {
     scope 2 {
     }
 
-    bb0: {
+    bb0: {                               // preds: []
         StorageLive(_1);                 // scope 0 at $DIR/box_expr.rs:7:9: 7:10
         _2 = SizeOf(S);                  // scope 2 at $DIR/box_expr.rs:7:13: 7:25
         _3 = AlignOf(S);                 // scope 2 at $DIR/box_expr.rs:7:13: 7:25
@@ -25,7 +25,7 @@ fn main() -> () {
                                          // + literal: Const { ty: unsafe fn(usize, usize) -> *mut u8 {alloc::alloc::exchange_malloc}, val: Value(Scalar(<ZST>)) }
     }
 
-    bb1: {
+    bb1: {                               // preds: [bb0]
         StorageLive(_5);                 // scope 0 at $DIR/box_expr.rs:7:13: 7:25
         _5 = ShallowInitBox(move _4, S); // scope 0 at $DIR/box_expr.rs:7:13: 7:25
         (*_5) = S::new() -> [return: bb2, unwind: bb8]; // scope 0 at $DIR/box_expr.rs:7:17: 7:25
@@ -34,12 +34,12 @@ fn main() -> () {
                                          // + literal: Const { ty: fn() -> S {S::new}, val: Value(Scalar(<ZST>)) }
     }
 
-    bb2: {
+    bb2: {                               // preds: [bb1]
         _1 = move _5;                    // scope 0 at $DIR/box_expr.rs:7:13: 7:25
         drop(_5) -> bb3;                 // scope 0 at $DIR/box_expr.rs:7:24: 7:25
     }
 
-    bb3: {
+    bb3: {                               // preds: [bb2]
         StorageDead(_5);                 // scope 0 at $DIR/box_expr.rs:7:24: 7:25
         StorageLive(_6);                 // scope 1 at $DIR/box_expr.rs:8:5: 8:12
         StorageLive(_7);                 // scope 1 at $DIR/box_expr.rs:8:10: 8:11
@@ -50,31 +50,31 @@ fn main() -> () {
                                          // + literal: Const { ty: fn(std::boxed::Box<S>) {std::mem::drop::<std::boxed::Box<S>>}, val: Value(Scalar(<ZST>)) }
     }
 
-    bb4: {
+    bb4: {                               // preds: [bb3]
         StorageDead(_7);                 // scope 1 at $DIR/box_expr.rs:8:11: 8:12
         StorageDead(_6);                 // scope 1 at $DIR/box_expr.rs:8:12: 8:13
         _0 = const ();                   // scope 0 at $DIR/box_expr.rs:6:11: 9:2
         drop(_1) -> bb5;                 // scope 0 at $DIR/box_expr.rs:9:1: 9:2
     }
 
-    bb5: {
+    bb5: {                               // preds: [bb4]
         StorageDead(_1);                 // scope 0 at $DIR/box_expr.rs:9:1: 9:2
         return;                          // scope 0 at $DIR/box_expr.rs:9:2: 9:2
     }
 
-    bb6 (cleanup): {
+    bb6 (cleanup): {                     // preds: [bb3]
         drop(_7) -> bb7;                 // scope 1 at $DIR/box_expr.rs:8:11: 8:12
     }
 
-    bb7 (cleanup): {
+    bb7 (cleanup): {                     // preds: [bb6]
         drop(_1) -> bb9;                 // scope 0 at $DIR/box_expr.rs:9:1: 9:2
     }
 
-    bb8 (cleanup): {
+    bb8 (cleanup): {                     // preds: [bb1]
         drop(_5) -> bb9;                 // scope 0 at $DIR/box_expr.rs:7:24: 7:25
     }
 
-    bb9 (cleanup): {
+    bb9 (cleanup): {                     // preds: [bb7, bb8]
         resume;                          // scope 0 at $DIR/box_expr.rs:6:1: 9:2
     }
 }
diff --git a/src/test/mir-opt/byte_slice.main.SimplifyCfg-elaborate-drops.after.mir b/src/test/mir-opt/byte_slice.main.SimplifyCfg-elaborate-drops.after.mir
@@ -11,7 +11,7 @@ fn main() -> () {
         }
     }
 
-    bb0: {
+    bb0: {                               // preds: []
         StorageLive(_1);                 // scope 0 at $DIR/byte_slice.rs:5:9: 5:10
         _1 = const b"foo";               // scope 0 at $DIR/byte_slice.rs:5:13: 5:19
                                          // ty::Const

diff --git a/src/test/mir-opt/combine_array_len.norm2.InstCombine.32bit.diff b/src/test/mir-opt/combine_array_len.norm2.InstCombine.32bit.diff
@@ -25,7 +25,7 @@
           }
       }
 
-      bb0: {
+      bb0: {                               // preds: []
           StorageLive(_2);                 // scope 0 at $DIR/combine_array_len.rs:5:9: 5:10
           StorageLive(_3);                 // scope 0 at $DIR/combine_array_len.rs:5:15: 5:16
           _3 = const 0_usize;              // scope 0 at $DIR/combine_array_len.rs:5:15: 5:16
@@ -35,7 +35,7 @@
           assert(move _5, "index out of bounds: the length is {} but the index is {}", move _4, _3) -> bb1; // scope 0 at $DIR/combine_array_len.rs:5:13: 5:17
       }
 
-      bb1: {
+      bb1: {                               // preds: [bb0]
           _2 = _1[_3];                     // scope 0 at $DIR/combine_array_len.rs:5:13: 5:17
           StorageDead(_3);                 // scope 0 at $DIR/combine_array_len.rs:5:17: 5:18
           StorageLive(_6);                 // scope 1 at $DIR/combine_array_len.rs:6:9: 6:10
@@ -47,7 +47,7 @@
           assert(move _9, "index out of bounds: the length is {} but the index is {}", move _8, _7) -> bb2; // scope 1 at $DIR/combine_array_len.rs:6:13: 6:17
       }
 
-      bb2: {
+      bb2: {                               // preds: [bb1]
           _6 = _1[_7];                     // scope 1 at $DIR/combine_array_len.rs:6:13: 6:17
           StorageDead(_7);                 // scope 1 at $DIR/combine_array_len.rs:6:17: 6:18
           StorageLive(_10);                // scope 2 at $DIR/combine_array_len.rs:7:5: 7:8