Auto merge of rust-lang#2195 - RalfJung:vtable-validation, r=RalfJung

test for Stacked Borrows error during vtable validation

Fixes rust-lang/miri#2123
Needs rust-lang#97761

rust-version

@@ -1 +1 @@
-09d52bc5d4260bac8b9a2ea8ac7a07c5c72906f1
+99930ac7f8cbb5d9b319b2e2e92794fd6f24f556

src/diagnostics.rs

@@ -16,10 +16,9 @@ pub enum TerminationInfo {
     Exit(i64),
     Abort(String),
     UnsupportedInIsolation(String),
-    ExperimentalUb {
+    StackedBorrowsUb {
         msg: String,
         help: Option<String>,
-        url: String,
         history: Option<TagHistory>,
     },
     Deadlock,
@@ -43,7 +42,7 @@ impl fmt::Display for TerminationInfo {
             Exit(code) => write!(f, "the evaluated program completed with exit code {}", code),
             Abort(msg) => write!(f, "{}", msg),
             UnsupportedInIsolation(msg) => write!(f, "{}", msg),
-            ExperimentalUb { msg, .. } => write!(f, "{}", msg),
+            StackedBorrowsUb { msg, .. } => write!(f, "{}", msg),
             Deadlock => write!(f, "the evaluated program deadlocked"),
             MultipleSymbolDefinitions { link_name, .. } =>
                 write!(f, "multiple definitions of symbol `{}`", link_name),
@@ -146,7 +145,7 @@ pub fn report_error<'tcx, 'mir>(
                 Exit(code) => return Some(*code),
                 Abort(_) => Some("abnormal termination"),
                 UnsupportedInIsolation(_) => Some("unsupported operation"),
-                ExperimentalUb { .. } => Some("Undefined Behavior"),
+                StackedBorrowsUb { .. } => Some("Undefined Behavior"),
                 Deadlock => Some("deadlock"),
                 MultipleSymbolDefinitions { .. } | SymbolShimClashing { .. } => None,
             };
@@ -157,11 +156,12 @@ pub fn report_error<'tcx, 'mir>(
                         (None, format!("pass the flag `-Zmiri-disable-isolation` to disable isolation;")),
                         (None, format!("or pass `-Zmiri-isolation-error=warn` to configure Miri to return an error code from isolated operations (if supported for that operation) and continue with a warning")),
                     ],
-                ExperimentalUb { url, help, history, .. } => {
+                StackedBorrowsUb { help, history, .. } => {
+                    let url = "https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md";
                     msg.extend(help.clone());
                     let mut helps = vec![
-                        (None, format!("this indicates a potential bug in the program: it performed an invalid operation, but the rules it violated are still experimental")),
-                        (None, format!("see {} for further information", url)),
+                        (None, format!("this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental")),
+                        (None, format!("see {url} for further information")),
                     ];
                     match history {
                         Some(TagHistory::Tagged {tag, created: (created_range, created_span), invalidated, protected }) => {

src/stacked_borrows.rs

@@ -250,14 +250,7 @@ pub fn err_sb_ub<'tcx>(
     help: Option<String>,
     history: Option<TagHistory>,
 ) -> InterpError<'tcx> {
-    err_machine_stop!(TerminationInfo::ExperimentalUb {
-        msg,
-        help,
-        url: format!(
-            "https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md"
-        ),
-        history
-    })
+    err_machine_stop!(TerminationInfo::StackedBorrowsUb { msg, help, history })
 }
 
 // # Stacked Borrows Core Begin

tests/fail/box-cell-alias.stderr

@@ -7,7 +7,7 @@ LL |     unsafe { (*ptr).set(20); }
    |              trying to reborrow <TAG> for SharedReadWrite permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
    |              this error occurs as part of a reborrow at ALLOC[0x0..0x1]
    |
-   = help: this indicates a potential bug in the program: it performed an invalid operation, but the rules it violated are still experimental
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
 help: <TAG> was created by a retag at offsets [0x0..0x1]
   --> $DIR/box-cell-alias.rs:LL:CC

tests/fail/stacked_borrows/alias_through_mutation.stderr

@@ -7,7 +7,7 @@ LL |     let _val = *target_alias;
    |                attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
    |                this error occurs as part of an access at ALLOC[0x0..0x4]
    |
-   = help: this indicates a potential bug in the program: it performed an invalid operation, but the rules it violated are still experimental
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
 help: <TAG> was created by a retag at offsets [0x0..0x4]
   --> $DIR/alias_through_mutation.rs:LL:CC

tests/fail/stacked_borrows/aliasing_mut1.stderr

@@ -4,7 +4,7 @@ error: Undefined Behavior: not granting access to tag <TAG> because incompatible
 LL | pub fn safe(_x: &mut i32, _y: &mut i32) {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ not granting access to tag <TAG> because incompatible item is protected: [Unique for <TAG> (call ID)]
    |
-   = help: this indicates a potential bug in the program: it performed an invalid operation, but the rules it violated are still experimental
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
 help: <TAG> was created by a retag at offsets [0x0..0x4]
   --> $DIR/aliasing_mut1.rs:LL:CC

tests/fail/stacked_borrows/aliasing_mut2.stderr

@@ -4,7 +4,7 @@ error: Undefined Behavior: not granting access to tag <TAG> because incompatible
 LL | pub fn safe(_x: &i32, _y: &mut i32) {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ not granting access to tag <TAG> because incompatible item is protected: [SharedReadOnly for <TAG> (call ID)]
    |
-   = help: this indicates a potential bug in the program: it performed an invalid operation, but the rules it violated are still experimental
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
 help: <TAG> was created by a retag at offsets [0x0..0x4]
   --> $DIR/aliasing_mut2.rs:LL:CC

tests/fail/stacked_borrows/aliasing_mut3.stderr

@@ -7,7 +7,7 @@ LL | pub fn safe(_x: &mut i32, _y: &i32) {}
    | trying to reborrow <untagged> for SharedReadOnly permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
    | this error occurs as part of a reborrow at ALLOC[0x0..0x4]
    |
-   = help: this indicates a potential bug in the program: it performed an invalid operation, but the rules it violated are still experimental
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
 help: tag was most recently created at offsets [0x0..0x4]
   --> $DIR/aliasing_mut3.rs:LL:CC

tests/fail/stacked_borrows/aliasing_mut4.stderr

@@ -4,7 +4,7 @@ error: Undefined Behavior: not granting access to tag <TAG> because incompatible
 LL | pub fn safe(_x: &i32, _y: &mut Cell<i32>) {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ not granting access to tag <TAG> because incompatible item is protected: [SharedReadOnly for <TAG> (call ID)]
    |
-   = help: this indicates a potential bug in the program: it performed an invalid operation, but the rules it violated are still experimental
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
 help: <TAG> was created by a retag at offsets [0x0..0x4]
   --> $DIR/aliasing_mut4.rs:LL:CC

tests/fail/stacked_borrows/box_exclusive_violation1.stderr

@@ -7,7 +7,7 @@ LL |   *our
    |   attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
    |   this error occurs as part of an access at ALLOC[0x0..0x4]
    |
-   = help: this indicates a potential bug in the program: it performed an invalid operation, but the rules it violated are still experimental
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
 help: <TAG> was created by a retag at offsets [0x0..0x4]
   --> $DIR/box_exclusive_violation1.rs:LL:CC

tests/fail/stacked_borrows/buggy_as_mut_slice.stderr

@@ -7,7 +7,7 @@ LL |     v1[1] = 5;
    |     attempting a write access using <TAG> at ALLOC[0x4], but that tag does not exist in the borrow stack for this location
    |     this error occurs as part of an access at ALLOC[0x4..0x8]
    |
-   = help: this indicates a potential bug in the program: it performed an invalid operation, but the rules it violated are still experimental
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
 help: <TAG> was created by a retag at offsets [0x0..0xc]
   --> $DIR/buggy_as_mut_slice.rs:LL:CC

tests/fail/stacked_borrows/buggy_split_at_mut.stderr

@@ -7,7 +7,7 @@ LL |     let (a, b) = safe::split_at_mut(&mut array, 0);
    |          trying to reborrow <TAG> for Unique permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
    |          this error occurs as part of a reborrow at ALLOC[0x0..0x10]
    |
-   = help: this indicates a potential bug in the program: it performed an invalid operation, but the rules it violated are still experimental
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
 help: <TAG> was created by a retag at offsets [0x0..0x10]
   --> $DIR/buggy_split_at_mut.rs:LL:CC

tests/fail/stacked_borrows/deallocate_against_barrier1.stderr

@@ -4,7 +4,7 @@ error: Undefined Behavior: deallocating while item is protected: [Unique for <TA
 LL |     unsafe { __rust_dealloc(ptr, layout.size(), layout.align()) }
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ deallocating while item is protected: [Unique for <TAG> (call ID)]
    |
-   = help: this indicates a potential bug in the program: it performed an invalid operation, but the rules it violated are still experimental
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
 
    = note: inside `std::alloc::dealloc` at RUSTLIB/alloc/src/alloc.rs:LL:CC

tests/fail/stacked_borrows/deallocate_against_barrier2.stderr

@@ -4,7 +4,7 @@ error: Undefined Behavior: deallocating while item is protected: [SharedReadWrit
 LL |     unsafe { __rust_dealloc(ptr, layout.size(), layout.align()) }
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ deallocating while item is protected: [SharedReadWrite for <TAG> (call ID)]
    |
-   = help: this indicates a potential bug in the program: it performed an invalid operation, but the rules it violated are still experimental
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
 
    = note: inside `std::alloc::dealloc` at RUSTLIB/alloc/src/alloc.rs:LL:CC

tests/fail/stacked_borrows/illegal_read1.stderr

@@ -7,7 +7,7 @@ LL |     let _val = *xref; // ...but any use of raw will invalidate our ref.
    |                attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
    |                this error occurs as part of an access at ALLOC[0x0..0x4]
    |
-   = help: this indicates a potential bug in the program: it performed an invalid operation, but the rules it violated are still experimental
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
 help: <TAG> was created by a retag at offsets [0x0..0x4]
   --> $DIR/illegal_read1.rs:LL:CC

tests/fail/stacked_borrows/illegal_read2.stderr

@@ -7,7 +7,7 @@ LL |     let _val = *xref; // ...but any use of raw will invalidate our ref.
    |                attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
    |                this error occurs as part of an access at ALLOC[0x0..0x4]
    |
-   = help: this indicates a potential bug in the program: it performed an invalid operation, but the rules it violated are still experimental
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
 help: <TAG> was created by a retag at offsets [0x0..0x4]
   --> $DIR/illegal_read2.rs:LL:CC

tests/fail/stacked_borrows/illegal_read3.stderr

@@ -7,7 +7,7 @@ LL |     let _val = *xref2;
    |                attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
    |                this error occurs as part of an access at ALLOC[0x0..0x4]
    |
-   = help: this indicates a potential bug in the program: it performed an invalid operation, but the rules it violated are still experimental
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
 help: <TAG> was created by a retag at offsets [0x0..0x4]
   --> $DIR/illegal_read3.rs:LL:CC

tests/fail/stacked_borrows/illegal_read4.stderr

@@ -7,7 +7,7 @@ LL |     let _illegal = *xref2;
    |                    attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
    |                    this error occurs as part of an access at ALLOC[0x0..0x4]
    |
-   = help: this indicates a potential bug in the program: it performed an invalid operation, but the rules it violated are still experimental
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
 help: <TAG> was created by a retag at offsets [0x0..0x4]
   --> $DIR/illegal_read4.rs:LL:CC

tests/fail/stacked_borrows/illegal_read5.stderr

@@ -7,7 +7,7 @@ LL |     let _val = *xref; // the mutable one is dead and gone
    |                attempting a read access using <TAG> at ALLOC[$HEX], but that tag does not exist in the borrow stack for this location
    |                this error occurs as part of an access at ALLOC[$HEX..$HEX]
    |
-   = help: this indicates a potential bug in the program: it performed an invalid operation, but the rules it violated are still experimental
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
 help: <TAG> was created by a retag at offsets [$HEX..$HEX]
   --> $DIR/illegal_read5.rs:LL:CC

tests/fail/stacked_borrows/illegal_read6.stderr

@@ -7,7 +7,7 @@ LL |     let _val = *raw;
    |                attempting a read access using <untagged> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
    |                this error occurs as part of an access at ALLOC[0x0..0x4]
    |
-   = help: this indicates a potential bug in the program: it performed an invalid operation, but the rules it violated are still experimental
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
 help: tag was most recently created at offsets [0x0..0x4]
   --> $DIR/illegal_read6.rs:LL:CC

tests/fail/stacked_borrows/illegal_read7.stderr

@@ -7,7 +7,7 @@ LL |     let _val = *x.get_mut();
    |                 trying to reborrow <TAG> for SharedReadWrite permission at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
    |                 this error occurs as part of a reborrow at ALLOC[0x0..0x4]
    |
-   = help: this indicates a potential bug in the program: it performed an invalid operation, but the rules it violated are still experimental
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
 help: <TAG> was created by a retag at offsets [0x0..0x4]
   --> $DIR/illegal_read7.rs:LL:CC

tests/fail/stacked_borrows/illegal_read8.stderr

@@ -7,7 +7,7 @@ LL |     let _fail = *y1;
    |                 attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
    |                 this error occurs as part of an access at ALLOC[0x0..0x4]
    |
-   = help: this indicates a potential bug in the program: it performed an invalid operation, but the rules it violated are still experimental
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
 help: <TAG> was created by a retag at offsets [0x0..0x4]
   --> $DIR/illegal_read8.rs:LL:CC

tests/fail/stacked_borrows/illegal_write1.stderr

@@ -7,7 +7,7 @@ LL |     let _x = *xref;
    |              attempting a read access using <TAG> at ALLOC[0x0], but that tag does not exist in the borrow stack for this location
    |              this error occurs as part of an access at ALLOC[0x0..0x4]
    |
-   = help: this indicates a potential bug in the program: it performed an invalid operation, but the rules it violated are still experimental
+   = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
 help: <TAG> was created by a retag at offsets [0x0..0x4]
   --> $DIR/illegal_write1.rs:LL:CC