diff options
7 files changed, 83 insertions, 27 deletions
diff --git a/src/tools/miri/src/borrow_tracker/stacked_borrows/mod.rs b/src/tools/miri/src/borrow_tracker/stacked_borrows/mod.rs index 603733f9dc0..1d75486a781 100644 --- a/src/tools/miri/src/borrow_tracker/stacked_borrows/mod.rs +++ b/src/tools/miri/src/borrow_tracker/stacked_borrows/mod.rs @@ -5,6 +5,7 @@ pub mod diagnostics; mod item; mod stack; +use std::cell::RefCell; use std::cmp; use std::fmt::Write; use std::mem; @@ -820,7 +821,19 @@ trait EvalContextPrivExt<'tcx, 'ecx>: crate::MiriInterpCxExt<'tcx> { // See https://github.com/rust-lang/unsafe-code-guidelines/issues/276. let size = match size { Some(size) => size, - None => return Ok(place.clone()), + None => { + // The first time this happens, show a warning. + thread_local! { static WARNING_SHOWN: RefCell<bool> = const { RefCell::new(false) }; } + WARNING_SHOWN.with_borrow_mut(|shown| { + if *shown { + return; + } + // Not yet shown. Show it! + *shown = true; + this.emit_diagnostic(NonHaltingDiagnostic::ExternTypeReborrow); + }); + return Ok(place.clone()); + } }; // Compute new borrow. diff --git a/src/tools/miri/src/diagnostics.rs b/src/tools/miri/src/diagnostics.rs index 647d7d44bb1..45a8a54bc29 100644 --- a/src/tools/miri/src/diagnostics.rs +++ b/src/tools/miri/src/diagnostics.rs @@ -130,6 +130,7 @@ pub enum NonHaltingDiagnostic { WeakMemoryOutdatedLoad { ptr: Pointer, }, + ExternTypeReborrow, } /// Level of Miri specific diagnostics @@ -593,6 +594,8 @@ impl<'tcx> MiriMachine<'tcx> { RejectedIsolatedOp(_) => ("operation rejected by isolation".to_string(), DiagLevel::Warning), Int2Ptr { .. } => ("integer-to-pointer cast".to_string(), DiagLevel::Warning), + ExternTypeReborrow => + ("reborrow of reference to `extern type`".to_string(), DiagLevel::Warning), CreatedPointerTag(..) | PoppedPointerTag(..) | CreatedCallId(..) @@ -630,6 +633,8 @@ impl<'tcx> MiriMachine<'tcx> { Int2Ptr { .. } => format!("integer-to-pointer cast"), WeakMemoryOutdatedLoad { ptr } => format!("weak memory emulation: outdated value returned from load at {ptr}"), + ExternTypeReborrow => + format!("reborrow of a reference to `extern type` is not properly supported"), }; let notes = match &e { @@ -647,34 +652,50 @@ impl<'tcx> MiriMachine<'tcx> { ( None, format!( - "This program is using integer-to-pointer casts or (equivalently) `ptr::with_exposed_provenance`, which means that Miri might miss pointer bugs in this program." + "this program is using integer-to-pointer casts or (equivalently) `ptr::with_exposed_provenance`, which means that Miri might miss pointer bugs in this program" ), ), ( None, format!( - "See https://doc.rust-lang.org/nightly/std/ptr/fn.with_exposed_provenance.html for more details on that operation." + "see https://doc.rust-lang.org/nightly/std/ptr/fn.with_exposed_provenance.html for more details on that operation" ), ), ( None, format!( - "To ensure that Miri does not miss bugs in your program, use Strict Provenance APIs (https://doc.rust-lang.org/nightly/std/ptr/index.html#strict-provenance, https://crates.io/crates/sptr) instead." + "to ensure that Miri does not miss bugs in your program, use Strict Provenance APIs (https://doc.rust-lang.org/nightly/std/ptr/index.html#strict-provenance, https://crates.io/crates/sptr) instead" ), ), ( None, format!( - "You can then set `MIRIFLAGS=-Zmiri-strict-provenance` to ensure you are not relying on `with_exposed_provenance` semantics." + "you can then set `MIRIFLAGS=-Zmiri-strict-provenance` to ensure you are not relying on `with_exposed_provenance` semantics" ), ), ( None, format!( - "Alternatively, `MIRIFLAGS=-Zmiri-permissive-provenance` disables this warning." + "alternatively, `MIRIFLAGS=-Zmiri-permissive-provenance` disables this warning" ), ), ], + ExternTypeReborrow => { + vec![ + ( + None, + format!( + "`extern type` are not compatible with the Stacked Borrows aliasing model implemented by Miri; Miri may miss bugs in this code" + ), + ), + ( + None, + format!( + "try running with `MIRIFLAGS=-Zmiri-tree-borrows` to use the more permissive but also even more experimental Tree Borrows aliasing checks instead" + ), + ), + ] + } _ => vec![], }; diff --git a/src/tools/miri/tests/fail/extern-type-field-offset.stderr b/src/tools/miri/tests/fail/extern-type-field-offset.stderr index 3ed5732b4eb..c07b63e0c03 100644 --- a/src/tools/miri/tests/fail/extern-type-field-offset.stderr +++ b/src/tools/miri/tests/fail/extern-type-field-offset.stderr @@ -1,3 +1,14 @@ +warning: reborrow of reference to `extern type` + --> $DIR/extern-type-field-offset.rs:LL:CC + | +LL | let x: &Newtype = unsafe { &*(&buf as *const _ as *const Newtype) }; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ reborrow of a reference to `extern type` is not properly supported + | + = help: `extern type` are not compatible with the Stacked Borrows aliasing model implemented by Miri; Miri may miss bugs in this code + = help: try running with `MIRIFLAGS=-Zmiri-tree-borrows` to use the more permissive but also even more experimental Tree Borrows aliasing checks instead + = note: BACKTRACE: + = note: inside `main` at $DIR/extern-type-field-offset.rs:LL:CC + error: unsupported operation: `extern type` field does not have a known offset --> $DIR/extern-type-field-offset.rs:LL:CC | @@ -10,5 +21,5 @@ LL | let _field = &x.a; note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace -error: aborting due to 1 previous error +error: aborting due to 1 previous error; 1 warning emitted diff --git a/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_slice_len.stderr b/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_slice_len.stderr index 217bc82010d..84023cf7937 100644 --- a/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_slice_len.stderr +++ b/src/tools/miri/tests/fail/intrinsics/ptr_metadata_uninit_slice_len.stderr @@ -4,11 +4,11 @@ warning: integer-to-pointer cast LL | (*p.as_mut_ptr().cast::<[*const i32; 2]>())[0] = 4 as *const i32; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ integer-to-pointer cast | - = help: This program is using integer-to-pointer casts or (equivalently) `ptr::with_exposed_provenance`, which means that Miri might miss pointer bugs in this program. - = help: See https://doc.rust-lang.org/nightly/std/ptr/fn.with_exposed_provenance.html for more details on that operation. - = help: To ensure that Miri does not miss bugs in your program, use Strict Provenance APIs (https://doc.rust-lang.org/nightly/std/ptr/index.html#strict-provenance, https://crates.io/crates/sptr) instead. - = help: You can then set `MIRIFLAGS=-Zmiri-strict-provenance` to ensure you are not relying on `with_exposed_provenance` semantics. - = help: Alternatively, `MIRIFLAGS=-Zmiri-permissive-provenance` disables this warning. + = help: this program is using integer-to-pointer casts or (equivalently) `ptr::with_exposed_provenance`, which means that Miri might miss pointer bugs in this program + = help: see https://doc.rust-lang.org/nightly/std/ptr/fn.with_exposed_provenance.html for more details on that operation + = help: to ensure that Miri does not miss bugs in your program, use Strict Provenance APIs (https://doc.rust-lang.org/nightly/std/ptr/index.html#strict-provenance, https://crates.io/crates/sptr) instead + = help: you can then set `MIRIFLAGS=-Zmiri-strict-provenance` to ensure you are not relying on `with_exposed_provenance` semantics + = help: alternatively, `MIRIFLAGS=-Zmiri-permissive-provenance` disables this warning = note: BACKTRACE: = note: inside `main` at $DIR/ptr_metadata_uninit_slice_len.rs:LL:CC diff --git a/src/tools/miri/tests/pass/box.stack.stderr b/src/tools/miri/tests/pass/box.stack.stderr index 341f84c8992..f2d01b518fc 100644 --- a/src/tools/miri/tests/pass/box.stack.stderr +++ b/src/tools/miri/tests/pass/box.stack.stderr @@ -4,11 +4,11 @@ warning: integer-to-pointer cast LL | let r2 = ((r as usize) + 0) as *mut i32; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ integer-to-pointer cast | - = help: This program is using integer-to-pointer casts or (equivalently) `ptr::with_exposed_provenance`, which means that Miri might miss pointer bugs in this program. - = help: See https://doc.rust-lang.org/nightly/std/ptr/fn.with_exposed_provenance.html for more details on that operation. - = help: To ensure that Miri does not miss bugs in your program, use Strict Provenance APIs (https://doc.rust-lang.org/nightly/std/ptr/index.html#strict-provenance, https://crates.io/crates/sptr) instead. - = help: You can then set `MIRIFLAGS=-Zmiri-strict-provenance` to ensure you are not relying on `with_exposed_provenance` semantics. - = help: Alternatively, `MIRIFLAGS=-Zmiri-permissive-provenance` disables this warning. + = help: this program is using integer-to-pointer casts or (equivalently) `ptr::with_exposed_provenance`, which means that Miri might miss pointer bugs in this program + = help: see https://doc.rust-lang.org/nightly/std/ptr/fn.with_exposed_provenance.html for more details on that operation + = help: to ensure that Miri does not miss bugs in your program, use Strict Provenance APIs (https://doc.rust-lang.org/nightly/std/ptr/index.html#strict-provenance, https://crates.io/crates/sptr) instead + = help: you can then set `MIRIFLAGS=-Zmiri-strict-provenance` to ensure you are not relying on `with_exposed_provenance` semantics + = help: alternatively, `MIRIFLAGS=-Zmiri-permissive-provenance` disables this warning = note: BACKTRACE: = note: inside `into_raw` at $DIR/box.rs:LL:CC note: inside `main` diff --git a/src/tools/miri/tests/pass/extern_types.stack.stderr b/src/tools/miri/tests/pass/extern_types.stack.stderr index 03a9167abbc..9b6f632eb5a 100644 --- a/src/tools/miri/tests/pass/extern_types.stack.stderr +++ b/src/tools/miri/tests/pass/extern_types.stack.stderr @@ -4,11 +4,22 @@ warning: integer-to-pointer cast LL | let x: &Foo = unsafe { &*(16 as *const Foo) }; | ^^^^^^^^^^^^^^^^^^ integer-to-pointer cast | - = help: This program is using integer-to-pointer casts or (equivalently) `ptr::with_exposed_provenance`, which means that Miri might miss pointer bugs in this program. - = help: See https://doc.rust-lang.org/nightly/std/ptr/fn.with_exposed_provenance.html for more details on that operation. - = help: To ensure that Miri does not miss bugs in your program, use Strict Provenance APIs (https://doc.rust-lang.org/nightly/std/ptr/index.html#strict-provenance, https://crates.io/crates/sptr) instead. - = help: You can then set `MIRIFLAGS=-Zmiri-strict-provenance` to ensure you are not relying on `with_exposed_provenance` semantics. - = help: Alternatively, `MIRIFLAGS=-Zmiri-permissive-provenance` disables this warning. + = help: this program is using integer-to-pointer casts or (equivalently) `ptr::with_exposed_provenance`, which means that Miri might miss pointer bugs in this program + = help: see https://doc.rust-lang.org/nightly/std/ptr/fn.with_exposed_provenance.html for more details on that operation + = help: to ensure that Miri does not miss bugs in your program, use Strict Provenance APIs (https://doc.rust-lang.org/nightly/std/ptr/index.html#strict-provenance, https://crates.io/crates/sptr) instead + = help: you can then set `MIRIFLAGS=-Zmiri-strict-provenance` to ensure you are not relying on `with_exposed_provenance` semantics + = help: alternatively, `MIRIFLAGS=-Zmiri-permissive-provenance` disables this warning + = note: BACKTRACE: + = note: inside `main` at $DIR/extern_types.rs:LL:CC + +warning: reborrow of reference to `extern type` + --> $DIR/extern_types.rs:LL:CC + | +LL | let x: &Foo = unsafe { &*(16 as *const Foo) }; + | ^^^^^^^^^^^^^^^^^^^^ reborrow of a reference to `extern type` is not properly supported + | + = help: `extern type` are not compatible with the Stacked Borrows aliasing model implemented by Miri; Miri may miss bugs in this code + = help: try running with `MIRIFLAGS=-Zmiri-tree-borrows` to use the more permissive but also even more experimental Tree Borrows aliasing checks instead = note: BACKTRACE: = note: inside `main` at $DIR/extern_types.rs:LL:CC diff --git a/src/tools/miri/tests/pass/stacked-borrows/issue-miri-2389.stderr b/src/tools/miri/tests/pass/stacked-borrows/issue-miri-2389.stderr index b0e1adf27d1..216bb6c76bc 100644 --- a/src/tools/miri/tests/pass/stacked-borrows/issue-miri-2389.stderr +++ b/src/tools/miri/tests/pass/stacked-borrows/issue-miri-2389.stderr @@ -4,11 +4,11 @@ warning: integer-to-pointer cast LL | let wildcard = &root0 as *const Cell<i32> as usize as *const Cell<i32>; | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ integer-to-pointer cast | - = help: This program is using integer-to-pointer casts or (equivalently) `ptr::with_exposed_provenance`, which means that Miri might miss pointer bugs in this program. - = help: See https://doc.rust-lang.org/nightly/std/ptr/fn.with_exposed_provenance.html for more details on that operation. - = help: To ensure that Miri does not miss bugs in your program, use Strict Provenance APIs (https://doc.rust-lang.org/nightly/std/ptr/index.html#strict-provenance, https://crates.io/crates/sptr) instead. - = help: You can then set `MIRIFLAGS=-Zmiri-strict-provenance` to ensure you are not relying on `with_exposed_provenance` semantics. - = help: Alternatively, `MIRIFLAGS=-Zmiri-permissive-provenance` disables this warning. + = help: this program is using integer-to-pointer casts or (equivalently) `ptr::with_exposed_provenance`, which means that Miri might miss pointer bugs in this program + = help: see https://doc.rust-lang.org/nightly/std/ptr/fn.with_exposed_provenance.html for more details on that operation + = help: to ensure that Miri does not miss bugs in your program, use Strict Provenance APIs (https://doc.rust-lang.org/nightly/std/ptr/index.html#strict-provenance, https://crates.io/crates/sptr) instead + = help: you can then set `MIRIFLAGS=-Zmiri-strict-provenance` to ensure you are not relying on `with_exposed_provenance` semantics + = help: alternatively, `MIRIFLAGS=-Zmiri-permissive-provenance` disables this warning = note: BACKTRACE: = note: inside `main` at $DIR/issue-miri-2389.rs:LL:CC |