diff options
Diffstat (limited to 'compiler/rustc_middle')
| -rw-r--r-- | compiler/rustc_middle/src/mir/mod.rs | 19 | ||||
| -rw-r--r-- | compiler/rustc_middle/src/mir/patch.rs | 25 | ||||
| -rw-r--r-- | compiler/rustc_middle/src/mir/syntax.rs | 17 | ||||
| -rw-r--r-- | compiler/rustc_middle/src/mir/terminator.rs | 97 | ||||
| -rw-r--r-- | compiler/rustc_middle/src/mir/visit.rs | 2 |
5 files changed, 119 insertions, 41 deletions
diff --git a/compiler/rustc_middle/src/mir/mod.rs b/compiler/rustc_middle/src/mir/mod.rs index 9ef3a1b30e4..6484c30167c 100644 --- a/compiler/rustc_middle/src/mir/mod.rs +++ b/compiler/rustc_middle/src/mir/mod.rs @@ -1275,9 +1275,11 @@ impl<O> AssertKind<O> { matches!(self, OverflowNeg(..) | Overflow(Add | Sub | Mul | Shl | Shr, ..)) } - /// Getting a description does not require `O` to be printable, and does not - /// require allocation. - /// The caller is expected to handle `BoundsCheck` and `MisalignedPointerDereference` separately. + /// Get the message that is printed at runtime when this assertion fails. + /// + /// The caller is expected to handle `BoundsCheck` and `MisalignedPointerDereference` by + /// invoking the appropriate lang item (panic_bounds_check/panic_misaligned_pointer_dereference) + /// instead of printing a static message. pub fn description(&self) -> &'static str { use AssertKind::*; match self { @@ -1303,6 +1305,11 @@ impl<O> AssertKind<O> { } /// Format the message arguments for the `assert(cond, msg..)` terminator in MIR printing. + /// + /// Needs to be kept in sync with the run-time behavior (which is defined by + /// `AssertKind::description` and the lang items mentioned in its docs). + /// Note that we deliberately show more details here than we do at runtime, such as the actual + /// numbers that overflowed -- it is much easier to do so here than at runtime. pub fn fmt_assert_args<W: Write>(&self, f: &mut W) -> fmt::Result where O: Debug, @@ -1358,6 +1365,12 @@ impl<O> AssertKind<O> { } } + /// Format the diagnostic message for use in a lint (e.g. when the assertion fails during const-eval). + /// + /// Needs to be kept in sync with the run-time behavior (which is defined by + /// `AssertKind::description` and the lang items mentioned in its docs). + /// Note that we deliberately show more details here than we do at runtime, such as the actual + /// numbers that overflowed -- it is much easier to do so here than at runtime. pub fn diagnostic_message(&self) -> DiagnosticMessage { use crate::fluent_generated::*; use AssertKind::*; diff --git a/compiler/rustc_middle/src/mir/patch.rs b/compiler/rustc_middle/src/mir/patch.rs index cd74a403ff6..da486c3465a 100644 --- a/compiler/rustc_middle/src/mir/patch.rs +++ b/compiler/rustc_middle/src/mir/patch.rs @@ -14,7 +14,8 @@ pub struct MirPatch<'tcx> { resume_block: Option<BasicBlock>, // Only for unreachable in cleanup path. unreachable_cleanup_block: Option<BasicBlock>, - terminate_block: Option<BasicBlock>, + // Cached block for UnwindTerminate (with reason) + terminate_block: Option<(BasicBlock, UnwindTerminateReason)>, body_span: Span, next_local: usize, } @@ -35,13 +36,15 @@ impl<'tcx> MirPatch<'tcx> { for (bb, block) in body.basic_blocks.iter_enumerated() { // Check if we already have a resume block - if let TerminatorKind::UnwindResume = block.terminator().kind && block.statements.is_empty() { + if matches!(block.terminator().kind, TerminatorKind::UnwindResume) + && block.statements.is_empty() + { result.resume_block = Some(bb); continue; } // Check if we already have an unreachable block - if let TerminatorKind::Unreachable = block.terminator().kind + if matches!(block.terminator().kind, TerminatorKind::Unreachable) && block.statements.is_empty() && block.is_cleanup { @@ -50,8 +53,10 @@ impl<'tcx> MirPatch<'tcx> { } // Check if we already have a terminate block - if let TerminatorKind::UnwindTerminate = block.terminator().kind && block.statements.is_empty() { - result.terminate_block = Some(bb); + if let TerminatorKind::UnwindTerminate(reason) = block.terminator().kind + && block.statements.is_empty() + { + result.terminate_block = Some((bb, reason)); continue; } } @@ -93,20 +98,20 @@ impl<'tcx> MirPatch<'tcx> { bb } - pub fn terminate_block(&mut self) -> BasicBlock { - if let Some(bb) = self.terminate_block { - return bb; + pub fn terminate_block(&mut self, reason: UnwindTerminateReason) -> BasicBlock { + if let Some((cached_bb, cached_reason)) = self.terminate_block && reason == cached_reason { + return cached_bb; } let bb = self.new_block(BasicBlockData { statements: vec![], terminator: Some(Terminator { source_info: SourceInfo::outermost(self.body_span), - kind: TerminatorKind::UnwindTerminate, + kind: TerminatorKind::UnwindTerminate(reason), }), is_cleanup: true, }); - self.terminate_block = Some(bb); + self.terminate_block = Some((bb, reason)); bb } diff --git a/compiler/rustc_middle/src/mir/syntax.rs b/compiler/rustc_middle/src/mir/syntax.rs index e91e822f915..79b64a491f4 100644 --- a/compiler/rustc_middle/src/mir/syntax.rs +++ b/compiler/rustc_middle/src/mir/syntax.rs @@ -621,7 +621,7 @@ pub enum TerminatorKind<'tcx> { /// /// Used to prevent unwinding for foreign items or with `-C unwind=abort`. Only permitted in /// cleanup blocks. - UnwindTerminate, + UnwindTerminate(UnwindTerminateReason), /// Returns from the function. /// @@ -813,7 +813,7 @@ impl TerminatorKind<'_> { TerminatorKind::Goto { .. } => "Goto", TerminatorKind::SwitchInt { .. } => "SwitchInt", TerminatorKind::UnwindResume => "UnwindResume", - TerminatorKind::UnwindTerminate => "UnwindTerminate", + TerminatorKind::UnwindTerminate(_) => "UnwindTerminate", TerminatorKind::Return => "Return", TerminatorKind::Unreachable => "Unreachable", TerminatorKind::Drop { .. } => "Drop", @@ -842,11 +842,22 @@ pub enum UnwindAction { /// Terminates the execution if unwind happens. /// /// Depending on the platform and situation this may cause a non-unwindable panic or abort. - Terminate, + Terminate(UnwindTerminateReason), /// Cleanups to be done. Cleanup(BasicBlock), } +/// The reason we are terminating the process during unwinding. +#[derive(Copy, Clone, Debug, PartialEq, Eq, TyEncodable, TyDecodable, Hash, HashStable)] +#[derive(TypeFoldable, TypeVisitable)] +pub enum UnwindTerminateReason { + /// Unwinding is just not possible given the ABI of this function. + Abi, + /// We were already cleaning up for an ongoing unwind, and a *second*, *nested* unwind was + /// triggered by the drop glue. + InCleanup, +} + /// Information about an assertion failure. #[derive(Clone, Hash, HashStable, PartialEq, Debug)] #[derive(TyEncodable, TyDecodable, TypeFoldable, TypeVisitable)] diff --git a/compiler/rustc_middle/src/mir/terminator.rs b/compiler/rustc_middle/src/mir/terminator.rs index bd87563e2bb..7eddf13b3fb 100644 --- a/compiler/rustc_middle/src/mir/terminator.rs +++ b/compiler/rustc_middle/src/mir/terminator.rs @@ -1,3 +1,4 @@ +use rustc_hir::LangItem; use smallvec::SmallVec; use super::{BasicBlock, InlineAsmOperand, Operand, SourceInfo, TerminatorKind, UnwindAction}; @@ -100,6 +101,40 @@ impl<'a> Iterator for SwitchTargetsIter<'a> { impl<'a> ExactSizeIterator for SwitchTargetsIter<'a> {} +impl UnwindAction { + fn cleanup_block(self) -> Option<BasicBlock> { + match self { + UnwindAction::Cleanup(bb) => Some(bb), + UnwindAction::Continue | UnwindAction::Unreachable | UnwindAction::Terminate(_) => None, + } + } +} + +impl UnwindTerminateReason { + pub fn as_str(self) -> &'static str { + // Keep this in sync with the messages in `core/src/panicking.rs`. + match self { + UnwindTerminateReason::Abi => "panic in a function that cannot unwind", + UnwindTerminateReason::InCleanup => "panic in a destructor during cleanup", + } + } + + /// A short representation of this used for MIR printing. + pub fn as_short_str(self) -> &'static str { + match self { + UnwindTerminateReason::Abi => "abi", + UnwindTerminateReason::InCleanup => "cleanup", + } + } + + pub fn lang_item(self) -> LangItem { + match self { + UnwindTerminateReason::Abi => LangItem::PanicCannotUnwind, + UnwindTerminateReason::InCleanup => LangItem::PanicInCleanup, + } + } +} + #[derive(Clone, Debug, TyEncodable, TyDecodable, HashStable, TypeFoldable, TypeVisitable)] pub struct Terminator<'tcx> { pub source_info: SourceInfo, @@ -156,7 +191,7 @@ impl<'tcx> TerminatorKind<'tcx> { Some(t).into_iter().chain((&[]).into_iter().copied()) } UnwindResume - | UnwindTerminate + | UnwindTerminate(_) | GeneratorDrop | Return | Unreachable @@ -198,7 +233,7 @@ impl<'tcx> TerminatorKind<'tcx> { Some(t).into_iter().chain(&mut []) } UnwindResume - | UnwindTerminate + | UnwindTerminate(_) | GeneratorDrop | Return | Unreachable @@ -215,7 +250,7 @@ impl<'tcx> TerminatorKind<'tcx> { match *self { TerminatorKind::Goto { .. } | TerminatorKind::UnwindResume - | TerminatorKind::UnwindTerminate + | TerminatorKind::UnwindTerminate(_) | TerminatorKind::Return | TerminatorKind::Unreachable | TerminatorKind::GeneratorDrop @@ -234,7 +269,7 @@ impl<'tcx> TerminatorKind<'tcx> { match *self { TerminatorKind::Goto { .. } | TerminatorKind::UnwindResume - | TerminatorKind::UnwindTerminate + | TerminatorKind::UnwindTerminate(_) | TerminatorKind::Return | TerminatorKind::Unreachable | TerminatorKind::GeneratorDrop @@ -271,18 +306,28 @@ impl<'tcx> Debug for TerminatorKind<'tcx> { let labels = self.fmt_successor_labels(); assert_eq!(successor_count, labels.len()); - let unwind = match self.unwind() { - // Not needed or included in successors - None | Some(UnwindAction::Cleanup(_)) => None, - Some(UnwindAction::Continue) => Some("unwind continue"), - Some(UnwindAction::Unreachable) => Some("unwind unreachable"), - Some(UnwindAction::Terminate) => Some("unwind terminate"), + // `Cleanup` is already included in successors + let show_unwind = !matches!(self.unwind(), None | Some(UnwindAction::Cleanup(_))); + let fmt_unwind = |fmt: &mut Formatter<'_>| -> fmt::Result { + write!(fmt, "unwind ")?; + match self.unwind() { + // Not needed or included in successors + None | Some(UnwindAction::Cleanup(_)) => unreachable!(), + Some(UnwindAction::Continue) => write!(fmt, "continue"), + Some(UnwindAction::Unreachable) => write!(fmt, "unreachable"), + Some(UnwindAction::Terminate(reason)) => { + write!(fmt, "terminate({})", reason.as_short_str()) + } + } }; - match (successor_count, unwind) { - (0, None) => Ok(()), - (0, Some(unwind)) => write!(fmt, " -> {unwind}"), - (1, None) => write!(fmt, " -> {:?}", self.successors().next().unwrap()), + match (successor_count, show_unwind) { + (0, false) => Ok(()), + (0, true) => { + write!(fmt, " -> ")?; + fmt_unwind(fmt) + } + (1, false) => write!(fmt, " -> {:?}", self.successors().next().unwrap()), _ => { write!(fmt, " -> [")?; for (i, target) in self.successors().enumerate() { @@ -291,8 +336,9 @@ impl<'tcx> Debug for TerminatorKind<'tcx> { } write!(fmt, "{}: {:?}", labels[i], target)?; } - if let Some(unwind) = unwind { - write!(fmt, ", {unwind}")?; + if show_unwind { + write!(fmt, ", ")?; + fmt_unwind(fmt)?; } write!(fmt, "]") } @@ -312,7 +358,9 @@ impl<'tcx> TerminatorKind<'tcx> { Return => write!(fmt, "return"), GeneratorDrop => write!(fmt, "generator_drop"), UnwindResume => write!(fmt, "resume"), - UnwindTerminate => write!(fmt, "abort"), + UnwindTerminate(reason) => { + write!(fmt, "abort({})", reason.as_short_str()) + } Yield { value, resume_arg, .. } => write!(fmt, "{resume_arg:?} = yield({value:?})"), Unreachable => write!(fmt, "unreachable"), Drop { place, .. } => write!(fmt, "drop({place:?})"), @@ -391,7 +439,7 @@ impl<'tcx> TerminatorKind<'tcx> { pub fn fmt_successor_labels(&self) -> Vec<Cow<'static, str>> { use self::TerminatorKind::*; match *self { - Return | UnwindResume | UnwindTerminate | Unreachable | GeneratorDrop => vec![], + Return | UnwindResume | UnwindTerminate(_) | Unreachable | GeneratorDrop => vec![], Goto { .. } => vec!["".into()], SwitchInt { ref targets, .. } => targets .values @@ -443,7 +491,8 @@ pub enum TerminatorEdges<'mir, 'tcx> { /// Special action for `Yield`, `Call` and `InlineAsm` terminators. AssignOnReturn { return_: Option<BasicBlock>, - unwind: UnwindAction, + /// The cleanup block, if it exists. + cleanup: Option<BasicBlock>, place: CallReturnPlaces<'mir, 'tcx>, }, /// Special edge for `SwitchInt`. @@ -486,7 +535,7 @@ impl<'tcx> TerminatorKind<'tcx> { pub fn edges(&self) -> TerminatorEdges<'_, 'tcx> { use TerminatorKind::*; match *self { - Return | UnwindResume | UnwindTerminate | GeneratorDrop | Unreachable => { + Return | UnwindResume | UnwindTerminate(_) | GeneratorDrop | Unreachable => { TerminatorEdges::None } @@ -496,7 +545,7 @@ impl<'tcx> TerminatorKind<'tcx> { | Drop { target, unwind, place: _, replace: _ } | FalseUnwind { real_target: target, unwind } => match unwind { UnwindAction::Cleanup(unwind) => TerminatorEdges::Double(target, unwind), - UnwindAction::Continue | UnwindAction::Terminate | UnwindAction::Unreachable => { + UnwindAction::Continue | UnwindAction::Terminate(_) | UnwindAction::Unreachable => { TerminatorEdges::Single(target) } }, @@ -508,7 +557,7 @@ impl<'tcx> TerminatorKind<'tcx> { Yield { resume: target, drop, resume_arg, value: _ } => { TerminatorEdges::AssignOnReturn { return_: Some(target), - unwind: drop.map_or(UnwindAction::Terminate, UnwindAction::Cleanup), + cleanup: drop, place: CallReturnPlaces::Yield(resume_arg), } } @@ -516,7 +565,7 @@ impl<'tcx> TerminatorKind<'tcx> { Call { unwind, destination, target, func: _, args: _, fn_span: _, call_source: _ } => { TerminatorEdges::AssignOnReturn { return_: target, - unwind, + cleanup: unwind.cleanup_block(), place: CallReturnPlaces::Call(destination), } } @@ -530,7 +579,7 @@ impl<'tcx> TerminatorKind<'tcx> { unwind, } => TerminatorEdges::AssignOnReturn { return_: destination, - unwind, + cleanup: unwind.cleanup_block(), place: CallReturnPlaces::InlineAsm(operands), }, diff --git a/compiler/rustc_middle/src/mir/visit.rs b/compiler/rustc_middle/src/mir/visit.rs index b3d3366ae10..87b04aabe6a 100644 --- a/compiler/rustc_middle/src/mir/visit.rs +++ b/compiler/rustc_middle/src/mir/visit.rs @@ -470,7 +470,7 @@ macro_rules! make_mir_visitor { match kind { TerminatorKind::Goto { .. } | TerminatorKind::UnwindResume | - TerminatorKind::UnwindTerminate | + TerminatorKind::UnwindTerminate(_) | TerminatorKind::GeneratorDrop | TerminatorKind::Unreachable | TerminatorKind::FalseEdge { .. } | |