diff options
Diffstat (limited to 'compiler/rustc_middle/src')
| -rw-r--r-- | compiler/rustc_middle/src/mir/syntax.rs | 41 | ||||
| -rw-r--r-- | compiler/rustc_middle/src/mir/terminator.rs | 144 | ||||
| -rw-r--r-- | compiler/rustc_middle/src/mir/visit.rs | 6 |
3 files changed, 103 insertions, 88 deletions
diff --git a/compiler/rustc_middle/src/mir/syntax.rs b/compiler/rustc_middle/src/mir/syntax.rs index cc35e6106e2..c2a12bb3b66 100644 --- a/compiler/rustc_middle/src/mir/syntax.rs +++ b/compiler/rustc_middle/src/mir/syntax.rs @@ -515,14 +515,14 @@ pub struct CopyNonOverlapping<'tcx> { /// /// A note on unwinding: Panics may occur during the execution of some terminators. Depending on the /// `-C panic` flag, this may either cause the program to abort or the call stack to unwind. Such -/// terminators have a `cleanup: Option<BasicBlock>` field on them. If stack unwinding occurs, then -/// once the current function is reached, execution continues at the given basic block, if any. If -/// `cleanup` is `None` then no cleanup is performed, and the stack continues unwinding. This is -/// equivalent to the execution of a `Resume` terminator. +/// terminators have a `unwind: UnwindAction` field on them. If stack unwinding occurs, then +/// once the current function is reached, an action will be taken based on the `unwind` field. +/// If the action is `Cleanup`, then the execution continues at the given basic block. If the +/// action is `Continue` then no cleanup is performed, and the stack continues unwinding. /// -/// The basic block pointed to by a `cleanup` field must have its `cleanup` flag set. `cleanup` -/// basic blocks have a couple restrictions: -/// 1. All `cleanup` fields in them must be `None`. +/// The basic block pointed to by a `Cleanup` unwind action must have its `cleanup` flag set. +/// `cleanup` basic blocks have a couple restrictions: +/// 1. All `unwind` fields in them must be `UnwindAction::Continue`. /// 2. `Return` terminators are not allowed in them. `Abort` and `Unwind` terminators are. /// 3. All other basic blocks (in the current body) that are reachable from `cleanup` basic blocks /// must also be `cleanup`. This is a part of the type system and checked statically, so it is @@ -604,7 +604,7 @@ pub enum TerminatorKind<'tcx> { /// > The drop glue is executed if, among all statements executed within this `Body`, an assignment to /// > the place or one of its "parents" occurred more recently than a move out of it. This does not /// > consider indirect assignments. - Drop { place: Place<'tcx>, target: BasicBlock, unwind: Option<BasicBlock> }, + Drop { place: Place<'tcx>, target: BasicBlock, unwind: UnwindAction }, /// Roughly speaking, evaluates the `func` operand and the arguments, and starts execution of /// the referred to function. The operand types must match the argument types of the function. @@ -628,8 +628,8 @@ pub enum TerminatorKind<'tcx> { destination: Place<'tcx>, /// Where to go after this call returns. If none, the call necessarily diverges. target: Option<BasicBlock>, - /// Cleanups to be done if the call unwinds. - cleanup: Option<BasicBlock>, + /// Action to be taken if the call unwinds. + unwind: UnwindAction, /// `true` if this is from a call in HIR rather than from an overloaded /// operator. True for overloaded function call. from_hir_call: bool, @@ -654,7 +654,7 @@ pub enum TerminatorKind<'tcx> { expected: bool, msg: AssertMessage<'tcx>, target: BasicBlock, - cleanup: Option<BasicBlock>, + unwind: UnwindAction, }, /// Marks a suspend point. @@ -720,9 +720,10 @@ pub enum TerminatorKind<'tcx> { /// in practice, but in order to avoid fragility we want to always /// consider it in borrowck. We don't want to accept programs which /// pass borrowck only when `panic=abort` or some assertions are disabled - /// due to release vs. debug mode builds. This needs to be an `Option` because + /// due to release vs. debug mode builds. + /// This field does not necessary have to be `UnwindAction::Cleanup` because /// of the `remove_noop_landing_pads` and `abort_unwinding_calls` passes. - unwind: Option<BasicBlock>, + unwind: UnwindAction, }, /// Block ends with an inline assembly block. This is a terminator since @@ -745,12 +746,22 @@ pub enum TerminatorKind<'tcx> { /// diverging (InlineAsmOptions::NORETURN). destination: Option<BasicBlock>, - /// Cleanup to be done if the inline assembly unwinds. This is present + /// Action to be taken if the inline assembly unwinds. This is present /// if and only if InlineAsmOptions::MAY_UNWIND is set. - cleanup: Option<BasicBlock>, + unwind: UnwindAction, }, } +/// Action to be taken when a stack unwind happens. +#[derive(Copy, Clone, Debug, PartialEq, TyEncodable, TyDecodable, Hash, HashStable)] +#[derive(TypeFoldable, TypeVisitable)] +pub enum UnwindAction { + // No action is to be taken. Continue unwinding. + Continue, + // Cleanups to be done. + Cleanup(BasicBlock), +} + /// Information about an assertion failure. #[derive(Clone, TyEncodable, TyDecodable, Hash, HashStable, PartialEq, TypeFoldable, TypeVisitable)] pub enum AssertKind<O> { diff --git a/compiler/rustc_middle/src/mir/terminator.rs b/compiler/rustc_middle/src/mir/terminator.rs index cd970270727..19aa01c12bd 100644 --- a/compiler/rustc_middle/src/mir/terminator.rs +++ b/compiler/rustc_middle/src/mir/terminator.rs @@ -1,6 +1,6 @@ use smallvec::SmallVec; -use super::{BasicBlock, InlineAsmOperand, Operand, SourceInfo, TerminatorKind}; +use super::{BasicBlock, InlineAsmOperand, Operand, SourceInfo, TerminatorKind, UnwindAction}; use rustc_ast::InlineAsmTemplatePiece; pub use rustc_ast::Mutability; use rustc_macros::HashStable; @@ -118,11 +118,11 @@ impl<'tcx> Terminator<'tcx> { self.kind.successors_mut() } - pub fn unwind(&self) -> Option<&Option<BasicBlock>> { + pub fn unwind(&self) -> Option<&UnwindAction> { self.kind.unwind() } - pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> { + pub fn unwind_mut(&mut self) -> Option<&mut UnwindAction> { self.kind.unwind_mut() } } @@ -135,34 +135,34 @@ impl<'tcx> TerminatorKind<'tcx> { pub fn successors(&self) -> Successors<'_> { use self::TerminatorKind::*; match *self { + Call { target: Some(t), unwind: UnwindAction::Cleanup(ref u), .. } + | Yield { resume: t, drop: Some(ref u), .. } + | Drop { target: t, unwind: UnwindAction::Cleanup(ref u), .. } + | Assert { target: t, unwind: UnwindAction::Cleanup(ref u), .. } + | FalseUnwind { real_target: t, unwind: UnwindAction::Cleanup(ref u) } + | InlineAsm { destination: Some(t), unwind: UnwindAction::Cleanup(ref u), .. } => { + Some(t).into_iter().chain(slice::from_ref(u).into_iter().copied()) + } + Goto { target: t } + | Call { target: None, unwind: UnwindAction::Cleanup(t), .. } + | Call { target: Some(t), unwind: _, .. } + | Yield { resume: t, drop: None, .. } + | Drop { target: t, unwind: _, .. } + | Assert { target: t, unwind: _, .. } + | FalseUnwind { real_target: t, unwind: _ } + | InlineAsm { destination: None, unwind: UnwindAction::Cleanup(t), .. } + | InlineAsm { destination: Some(t), unwind: _, .. } => { + Some(t).into_iter().chain((&[]).into_iter().copied()) + } Resume | Abort | GeneratorDrop | Return | Unreachable - | Call { target: None, cleanup: None, .. } - | InlineAsm { destination: None, cleanup: None, .. } => { + | Call { target: None, unwind: _, .. } + | InlineAsm { destination: None, unwind: _, .. } => { None.into_iter().chain((&[]).into_iter().copied()) } - Goto { target: t } - | Call { target: None, cleanup: Some(t), .. } - | Call { target: Some(t), cleanup: None, .. } - | Yield { resume: t, drop: None, .. } - | Drop { target: t, unwind: None, .. } - | Assert { target: t, cleanup: None, .. } - | FalseUnwind { real_target: t, unwind: None } - | InlineAsm { destination: Some(t), cleanup: None, .. } - | InlineAsm { destination: None, cleanup: Some(t), .. } => { - Some(t).into_iter().chain((&[]).into_iter().copied()) - } - Call { target: Some(t), cleanup: Some(ref u), .. } - | Yield { resume: t, drop: Some(ref u), .. } - | Drop { target: t, unwind: Some(ref u), .. } - | Assert { target: t, cleanup: Some(ref u), .. } - | FalseUnwind { real_target: t, unwind: Some(ref u) } - | InlineAsm { destination: Some(t), cleanup: Some(ref u), .. } => { - Some(t).into_iter().chain(slice::from_ref(u).into_iter().copied()) - } SwitchInt { ref targets, .. } => { None.into_iter().chain(targets.targets.iter().copied()) } @@ -175,32 +175,34 @@ impl<'tcx> TerminatorKind<'tcx> { pub fn successors_mut(&mut self) -> SuccessorsMut<'_> { use self::TerminatorKind::*; match *self { + Call { target: Some(ref mut t), unwind: UnwindAction::Cleanup(ref mut u), .. } + | Yield { resume: ref mut t, drop: Some(ref mut u), .. } + | Drop { target: ref mut t, unwind: UnwindAction::Cleanup(ref mut u), .. } + | Assert { target: ref mut t, unwind: UnwindAction::Cleanup(ref mut u), .. } + | FalseUnwind { real_target: ref mut t, unwind: UnwindAction::Cleanup(ref mut u) } + | InlineAsm { + destination: Some(ref mut t), + unwind: UnwindAction::Cleanup(ref mut u), + .. + } => Some(t).into_iter().chain(slice::from_mut(u)), + Goto { target: ref mut t } + | Call { target: None, unwind: UnwindAction::Cleanup(ref mut t), .. } + | Call { target: Some(ref mut t), unwind: _, .. } + | Yield { resume: ref mut t, drop: None, .. } + | Drop { target: ref mut t, unwind: _, .. } + | Assert { target: ref mut t, unwind: _, .. } + | FalseUnwind { real_target: ref mut t, unwind: _ } + | InlineAsm { destination: None, unwind: UnwindAction::Cleanup(ref mut t), .. } + | InlineAsm { destination: Some(ref mut t), unwind: _, .. } => { + Some(t).into_iter().chain(&mut []) + } Resume | Abort | GeneratorDrop | Return | Unreachable - | Call { target: None, cleanup: None, .. } - | InlineAsm { destination: None, cleanup: None, .. } => None.into_iter().chain(&mut []), - Goto { target: ref mut t } - | Call { target: None, cleanup: Some(ref mut t), .. } - | Call { target: Some(ref mut t), cleanup: None, .. } - | Yield { resume: ref mut t, drop: None, .. } - | Drop { target: ref mut t, unwind: None, .. } - | Assert { target: ref mut t, cleanup: None, .. } - | FalseUnwind { real_target: ref mut t, unwind: None } - | InlineAsm { destination: Some(ref mut t), cleanup: None, .. } - | InlineAsm { destination: None, cleanup: Some(ref mut t), .. } => { - Some(t).into_iter().chain(&mut []) - } - Call { target: Some(ref mut t), cleanup: Some(ref mut u), .. } - | Yield { resume: ref mut t, drop: Some(ref mut u), .. } - | Drop { target: ref mut t, unwind: Some(ref mut u), .. } - | Assert { target: ref mut t, cleanup: Some(ref mut u), .. } - | FalseUnwind { real_target: ref mut t, unwind: Some(ref mut u) } - | InlineAsm { destination: Some(ref mut t), cleanup: Some(ref mut u), .. } => { - Some(t).into_iter().chain(slice::from_mut(u)) - } + | Call { target: None, unwind: _, .. } + | InlineAsm { destination: None, unwind: _, .. } => None.into_iter().chain(&mut []), SwitchInt { ref mut targets, .. } => None.into_iter().chain(&mut targets.targets), FalseEdge { ref mut real_target, ref mut imaginary_target } => { Some(real_target).into_iter().chain(slice::from_mut(imaginary_target)) @@ -208,7 +210,7 @@ impl<'tcx> TerminatorKind<'tcx> { } } - pub fn unwind(&self) -> Option<&Option<BasicBlock>> { + pub fn unwind(&self) -> Option<&UnwindAction> { match *self { TerminatorKind::Goto { .. } | TerminatorKind::Resume @@ -219,15 +221,15 @@ impl<'tcx> TerminatorKind<'tcx> { | TerminatorKind::Yield { .. } | TerminatorKind::SwitchInt { .. } | TerminatorKind::FalseEdge { .. } => None, - TerminatorKind::Call { cleanup: ref unwind, .. } - | TerminatorKind::Assert { cleanup: ref unwind, .. } + TerminatorKind::Call { ref unwind, .. } + | TerminatorKind::Assert { ref unwind, .. } | TerminatorKind::Drop { ref unwind, .. } | TerminatorKind::FalseUnwind { ref unwind, .. } - | TerminatorKind::InlineAsm { cleanup: ref unwind, .. } => Some(unwind), + | TerminatorKind::InlineAsm { ref unwind, .. } => Some(unwind), } } - pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> { + pub fn unwind_mut(&mut self) -> Option<&mut UnwindAction> { match *self { TerminatorKind::Goto { .. } | TerminatorKind::Resume @@ -238,11 +240,11 @@ impl<'tcx> TerminatorKind<'tcx> { | TerminatorKind::Yield { .. } | TerminatorKind::SwitchInt { .. } | TerminatorKind::FalseEdge { .. } => None, - TerminatorKind::Call { cleanup: ref mut unwind, .. } - | TerminatorKind::Assert { cleanup: ref mut unwind, .. } + TerminatorKind::Call { ref mut unwind, .. } + | TerminatorKind::Assert { ref mut unwind, .. } | TerminatorKind::Drop { ref mut unwind, .. } | TerminatorKind::FalseUnwind { ref mut unwind, .. } - | TerminatorKind::InlineAsm { cleanup: ref mut unwind, .. } => Some(unwind), + | TerminatorKind::InlineAsm { ref mut unwind, .. } => Some(unwind), } } @@ -386,31 +388,33 @@ impl<'tcx> TerminatorKind<'tcx> { .map(|&u| Cow::Owned(u.to_string())) .chain(iter::once("otherwise".into())) .collect(), - Call { target: Some(_), cleanup: Some(_), .. } => { + Call { target: Some(_), unwind: UnwindAction::Cleanup(_), .. } => { vec!["return".into(), "unwind".into()] } - Call { target: Some(_), cleanup: None, .. } => vec!["return".into()], - Call { target: None, cleanup: Some(_), .. } => vec!["unwind".into()], - Call { target: None, cleanup: None, .. } => vec![], + Call { target: Some(_), unwind: UnwindAction::Continue, .. } => vec!["return".into()], + Call { target: None, unwind: UnwindAction::Cleanup(_), .. } => vec!["unwind".into()], + Call { target: None, unwind: UnwindAction::Continue, .. } => vec![], Yield { drop: Some(_), .. } => vec!["resume".into(), "drop".into()], Yield { drop: None, .. } => vec!["resume".into()], - Drop { unwind: None, .. } => { - vec!["return".into()] - } - Drop { unwind: Some(_), .. } => { - vec!["return".into(), "unwind".into()] - } - Assert { cleanup: None, .. } => vec!["".into()], + Drop { unwind: UnwindAction::Continue, .. } => vec!["return".into()], + Drop { unwind: UnwindAction::Cleanup(_), .. } => vec!["return".into(), "unwind".into()], + Assert { unwind: UnwindAction::Continue, .. } => vec!["".into()], Assert { .. } => vec!["success".into(), "unwind".into()], FalseEdge { .. } => vec!["real".into(), "imaginary".into()], - FalseUnwind { unwind: Some(_), .. } => vec!["real".into(), "cleanup".into()], - FalseUnwind { unwind: None, .. } => vec!["real".into()], - InlineAsm { destination: Some(_), cleanup: Some(_), .. } => { + FalseUnwind { unwind: UnwindAction::Cleanup(_), .. } => { + vec!["real".into(), "cleanup".into()] + } + FalseUnwind { unwind: UnwindAction::Continue, .. } => vec!["real".into()], + InlineAsm { destination: Some(_), unwind: UnwindAction::Cleanup(_), .. } => { vec!["return".into(), "unwind".into()] } - InlineAsm { destination: Some(_), cleanup: None, .. } => vec!["return".into()], - InlineAsm { destination: None, cleanup: Some(_), .. } => vec!["unwind".into()], - InlineAsm { destination: None, cleanup: None, .. } => vec![], + InlineAsm { destination: Some(_), unwind: UnwindAction::Continue, .. } => { + vec!["return".into()] + } + InlineAsm { destination: None, unwind: UnwindAction::Cleanup(_), .. } => { + vec!["unwind".into()] + } + InlineAsm { destination: None, unwind: UnwindAction::Continue, .. } => vec![], } } } diff --git a/compiler/rustc_middle/src/mir/visit.rs b/compiler/rustc_middle/src/mir/visit.rs index 7aa446ae966..243c62f4a9c 100644 --- a/compiler/rustc_middle/src/mir/visit.rs +++ b/compiler/rustc_middle/src/mir/visit.rs @@ -509,7 +509,7 @@ macro_rules! make_mir_visitor { args, destination, target: _, - cleanup: _, + unwind: _, from_hir_call: _, fn_span: _ } => { @@ -529,7 +529,7 @@ macro_rules! make_mir_visitor { expected: _, msg, target: _, - cleanup: _, + unwind: _, } => { self.visit_operand(cond, location); self.visit_assert_message(msg, location); @@ -555,7 +555,7 @@ macro_rules! make_mir_visitor { options: _, line_spans: _, destination: _, - cleanup: _, + unwind: _, } => { for op in operands { match op { |