X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=src%2Flibrustc_middle%2Fmir%2Fmod.rs;h=ae59f8c542d8c5ece510ba471023358990abe0ab;hb=d6bee55855093d86c7e110116beebb369cd89654;hp=0ed0d9050078c04e34e61a6139e948f71833d343;hpb=3951a98ec5a53e527f0b2d1791b3db31738a107a;p=rust.git diff --git a/src/librustc_middle/mir/mod.rs b/src/librustc_middle/mir/mod.rs index 0ed0d905007..ae59f8c542d 100644 --- a/src/librustc_middle/mir/mod.rs +++ b/src/librustc_middle/mir/mod.rs @@ -19,7 +19,6 @@ use polonius_engine::Atom; pub use rustc_ast::ast::Mutability; -use rustc_ast::ast::{InlineAsmOptions, InlineAsmTemplatePiece}; use rustc_data_structures::fx::FxHashSet; use rustc_data_structures::graph::dominators::{dominators, Dominators}; use rustc_data_structures::graph::{self, GraphSuccessors}; @@ -45,6 +44,8 @@ mod predecessors; mod query; pub mod tcx; +pub mod terminator; +pub use terminator::*; pub mod traversal; mod type_foldable; pub mod visit; @@ -1046,191 +1047,6 @@ pub struct BasicBlockData<'tcx> { pub is_cleanup: bool, } -#[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)] -pub struct Terminator<'tcx> { - pub source_info: SourceInfo, - pub kind: TerminatorKind<'tcx>, -} - -#[derive(Clone, RustcEncodable, RustcDecodable, HashStable, PartialEq)] -pub enum TerminatorKind<'tcx> { - /// Block should have one successor in the graph; we jump there. - Goto { target: BasicBlock }, - - /// Operand evaluates to an integer; jump depending on its value - /// to one of the targets, and otherwise fallback to `otherwise`. - SwitchInt { - /// The discriminant value being tested. - discr: Operand<'tcx>, - - /// The type of value being tested. - /// This is always the same as the type of `discr`. - /// FIXME: remove this redundant information. Currently, it is relied on by pretty-printing. - switch_ty: Ty<'tcx>, - - /// Possible values. The locations to branch to in each case - /// are found in the corresponding indices from the `targets` vector. - values: Cow<'tcx, [u128]>, - - /// Possible branch sites. The last element of this vector is used - /// for the otherwise branch, so targets.len() == values.len() + 1 - /// should hold. - // - // This invariant is quite non-obvious and also could be improved. - // One way to make this invariant is to have something like this instead: - // - // branches: Vec<(ConstInt, BasicBlock)>, - // otherwise: Option // exhaustive if None - // - // However we’ve decided to keep this as-is until we figure a case - // where some other approach seems to be strictly better than other. - targets: Vec, - }, - - /// Indicates that the landing pad is finished and unwinding should - /// continue. Emitted by `build::scope::diverge_cleanup`. - Resume, - - /// Indicates that the landing pad is finished and that the process - /// should abort. Used to prevent unwinding for foreign items. - Abort, - - /// Indicates a normal return. The return place should have - /// been filled in before this executes. This can occur multiple times - /// in different basic blocks. - Return, - - /// Indicates a terminator that can never be reached. - Unreachable, - - /// Drop the `Place`. - Drop { place: Place<'tcx>, target: BasicBlock, unwind: Option }, - - /// Drop the `Place` and assign the new value over it. This ensures - /// that the assignment to `P` occurs *even if* the destructor for - /// place unwinds. Its semantics are best explained by the - /// elaboration: - /// - /// ``` - /// BB0 { - /// DropAndReplace(P <- V, goto BB1, unwind BB2) - /// } - /// ``` - /// - /// becomes - /// - /// ``` - /// BB0 { - /// Drop(P, goto BB1, unwind BB2) - /// } - /// BB1 { - /// // P is now uninitialized - /// P <- V - /// } - /// BB2 { - /// // P is now uninitialized -- its dtor panicked - /// P <- V - /// } - /// ``` - DropAndReplace { - place: Place<'tcx>, - value: Operand<'tcx>, - target: BasicBlock, - unwind: Option, - }, - - /// Block ends with a call of a converging function. - Call { - /// The function that’s being called. - func: Operand<'tcx>, - /// Arguments the function is called with. - /// These are owned by the callee, which is free to modify them. - /// This allows the memory occupied by "by-value" arguments to be - /// reused across function calls without duplicating the contents. - args: Vec>, - /// Destination for the return value. If some, the call is converging. - destination: Option<(Place<'tcx>, BasicBlock)>, - /// Cleanups to be done if the call unwinds. - cleanup: Option, - /// `true` if this is from a call in HIR rather than from an overloaded - /// operator. True for overloaded function call. - from_hir_call: bool, - /// This `Span` is the span of the function, without the dot and receiver - /// (e.g. `foo(a, b)` in `x.foo(a, b)` - fn_span: Span, - }, - - /// Jump to the target if the condition has the expected value, - /// otherwise panic with a message and a cleanup target. - Assert { - cond: Operand<'tcx>, - expected: bool, - msg: AssertMessage<'tcx>, - target: BasicBlock, - cleanup: Option, - }, - - /// A suspend point. - Yield { - /// The value to return. - value: Operand<'tcx>, - /// Where to resume to. - resume: BasicBlock, - /// The place to store the resume argument in. - resume_arg: Place<'tcx>, - /// Cleanup to be done if the generator is dropped at this suspend point. - drop: Option, - }, - - /// Indicates the end of the dropping of a generator. - GeneratorDrop, - - /// A block where control flow only ever takes one real path, but borrowck - /// needs to be more conservative. - FalseEdge { - /// The target normal control flow will take. - real_target: BasicBlock, - /// A block control flow could conceptually jump to, but won't in - /// practice. - imaginary_target: BasicBlock, - }, - /// A terminator for blocks that only take one path in reality, but where we - /// reserve the right to unwind in borrowck, even if it won't happen in practice. - /// This can arise in infinite loops with no function calls for example. - FalseUnwind { - /// The target normal control flow will take. - real_target: BasicBlock, - /// The imaginary cleanup block link. This particular path will never be taken - /// 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 - /// of the `remove_noop_landing_pads` and `no_landing_pads` passes. - unwind: Option, - }, - - /// Block ends with an inline assembly block. This is a terminator since - /// inline assembly is allowed to diverge. - InlineAsm { - /// The template for the inline assembly, with placeholders. - template: &'tcx [InlineAsmTemplatePiece], - - /// The operands for the inline assembly, as `Operand`s or `Place`s. - operands: Vec>, - - /// Miscellaneous options for the inline assembly. - options: InlineAsmOptions, - - /// Source spans for each line of the inline assembly code. These are - /// used to map assembler errors back to the line in the source code. - line_spans: &'tcx [Span], - - /// Destination block after the inline assembly returns, unless it is - /// diverging (InlineAsmOptions::NORETURN). - destination: Option, - }, -} - /// Information about an assertion failure. #[derive(Clone, RustcEncodable, RustcDecodable, HashStable, PartialEq)] pub enum AssertKind { @@ -1279,149 +1095,6 @@ pub enum InlineAsmOperand<'tcx> { pub type SuccessorsMut<'a> = iter::Chain, slice::IterMut<'a, BasicBlock>>; -impl<'tcx> Terminator<'tcx> { - pub fn successors(&self) -> Successors<'_> { - self.kind.successors() - } - - pub fn successors_mut(&mut self) -> SuccessorsMut<'_> { - self.kind.successors_mut() - } - - pub fn unwind(&self) -> Option<&Option> { - self.kind.unwind() - } - - pub fn unwind_mut(&mut self) -> Option<&mut Option> { - self.kind.unwind_mut() - } -} - -impl<'tcx> TerminatorKind<'tcx> { - pub fn if_( - tcx: TyCtxt<'tcx>, - cond: Operand<'tcx>, - t: BasicBlock, - f: BasicBlock, - ) -> TerminatorKind<'tcx> { - static BOOL_SWITCH_FALSE: &[u128] = &[0]; - TerminatorKind::SwitchInt { - discr: cond, - switch_ty: tcx.types.bool, - values: From::from(BOOL_SWITCH_FALSE), - targets: vec![f, t], - } - } - - pub fn successors(&self) -> Successors<'_> { - use self::TerminatorKind::*; - match *self { - Resume - | Abort - | GeneratorDrop - | Return - | Unreachable - | Call { destination: None, cleanup: None, .. } - | InlineAsm { destination: None, .. } => None.into_iter().chain(&[]), - Goto { target: ref t } - | Call { destination: None, cleanup: Some(ref t), .. } - | Call { destination: Some((_, ref t)), cleanup: None, .. } - | Yield { resume: ref t, drop: None, .. } - | DropAndReplace { target: ref t, unwind: None, .. } - | Drop { target: ref t, unwind: None, .. } - | Assert { target: ref t, cleanup: None, .. } - | FalseUnwind { real_target: ref t, unwind: None } - | InlineAsm { destination: Some(ref t), .. } => Some(t).into_iter().chain(&[]), - Call { destination: Some((_, ref t)), cleanup: Some(ref u), .. } - | Yield { resume: ref t, drop: Some(ref u), .. } - | DropAndReplace { target: ref t, unwind: Some(ref u), .. } - | Drop { target: ref t, unwind: Some(ref u), .. } - | Assert { target: ref t, cleanup: Some(ref u), .. } - | FalseUnwind { real_target: ref t, unwind: Some(ref u) } => { - Some(t).into_iter().chain(slice::from_ref(u)) - } - SwitchInt { ref targets, .. } => None.into_iter().chain(&targets[..]), - FalseEdge { ref real_target, ref imaginary_target } => { - Some(real_target).into_iter().chain(slice::from_ref(imaginary_target)) - } - } - } - - pub fn successors_mut(&mut self) -> SuccessorsMut<'_> { - use self::TerminatorKind::*; - match *self { - Resume - | Abort - | GeneratorDrop - | Return - | Unreachable - | Call { destination: None, cleanup: None, .. } - | InlineAsm { destination: None, .. } => None.into_iter().chain(&mut []), - Goto { target: ref mut t } - | Call { destination: None, cleanup: Some(ref mut t), .. } - | Call { destination: Some((_, ref mut t)), cleanup: None, .. } - | Yield { resume: ref mut t, drop: None, .. } - | DropAndReplace { target: ref mut t, unwind: 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), .. } => Some(t).into_iter().chain(&mut []), - Call { destination: Some((_, ref mut t)), cleanup: Some(ref mut u), .. } - | Yield { resume: ref mut t, drop: Some(ref mut u), .. } - | DropAndReplace { target: ref mut t, unwind: 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) } => { - Some(t).into_iter().chain(slice::from_mut(u)) - } - SwitchInt { ref mut targets, .. } => None.into_iter().chain(&mut targets[..]), - FalseEdge { ref mut real_target, ref mut imaginary_target } => { - Some(real_target).into_iter().chain(slice::from_mut(imaginary_target)) - } - } - } - - pub fn unwind(&self) -> Option<&Option> { - match *self { - TerminatorKind::Goto { .. } - | TerminatorKind::Resume - | TerminatorKind::Abort - | TerminatorKind::Return - | TerminatorKind::Unreachable - | TerminatorKind::GeneratorDrop - | TerminatorKind::Yield { .. } - | TerminatorKind::SwitchInt { .. } - | TerminatorKind::FalseEdge { .. } - | TerminatorKind::InlineAsm { .. } => None, - TerminatorKind::Call { cleanup: ref unwind, .. } - | TerminatorKind::Assert { cleanup: ref unwind, .. } - | TerminatorKind::DropAndReplace { ref unwind, .. } - | TerminatorKind::Drop { ref unwind, .. } - | TerminatorKind::FalseUnwind { ref unwind, .. } => Some(unwind), - } - } - - pub fn unwind_mut(&mut self) -> Option<&mut Option> { - match *self { - TerminatorKind::Goto { .. } - | TerminatorKind::Resume - | TerminatorKind::Abort - | TerminatorKind::Return - | TerminatorKind::Unreachable - | TerminatorKind::GeneratorDrop - | TerminatorKind::Yield { .. } - | TerminatorKind::SwitchInt { .. } - | TerminatorKind::FalseEdge { .. } - | TerminatorKind::InlineAsm { .. } => None, - TerminatorKind::Call { cleanup: ref mut unwind, .. } - | TerminatorKind::Assert { cleanup: ref mut unwind, .. } - | TerminatorKind::DropAndReplace { ref mut unwind, .. } - | TerminatorKind::Drop { ref mut unwind, .. } - | TerminatorKind::FalseUnwind { ref mut unwind, .. } => Some(unwind), - } - } -} - impl<'tcx> BasicBlockData<'tcx> { pub fn new(terminator: Option>) -> BasicBlockData<'tcx> { BasicBlockData { statements: vec![], terminator, is_cleanup: false } @@ -1628,169 +1301,6 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { } } -impl<'tcx> Debug for TerminatorKind<'tcx> { - fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result { - self.fmt_head(fmt)?; - let successor_count = self.successors().count(); - let labels = self.fmt_successor_labels(); - assert_eq!(successor_count, labels.len()); - - match successor_count { - 0 => Ok(()), - - 1 => write!(fmt, " -> {:?}", self.successors().next().unwrap()), - - _ => { - write!(fmt, " -> [")?; - for (i, target) in self.successors().enumerate() { - if i > 0 { - write!(fmt, ", ")?; - } - write!(fmt, "{}: {:?}", labels[i], target)?; - } - write!(fmt, "]") - } - } - } -} - -impl<'tcx> TerminatorKind<'tcx> { - /// Writes the "head" part of the terminator; that is, its name and the data it uses to pick the - /// successor basic block, if any. The only information not included is the list of possible - /// successors, which may be rendered differently between the text and the graphviz format. - pub fn fmt_head(&self, fmt: &mut W) -> fmt::Result { - use self::TerminatorKind::*; - match self { - Goto { .. } => write!(fmt, "goto"), - SwitchInt { discr, .. } => write!(fmt, "switchInt({:?})", discr), - Return => write!(fmt, "return"), - GeneratorDrop => write!(fmt, "generator_drop"), - Resume => write!(fmt, "resume"), - Abort => write!(fmt, "abort"), - Yield { value, resume_arg, .. } => write!(fmt, "{:?} = yield({:?})", resume_arg, value), - Unreachable => write!(fmt, "unreachable"), - Drop { place, .. } => write!(fmt, "drop({:?})", place), - DropAndReplace { place, value, .. } => { - write!(fmt, "replace({:?} <- {:?})", place, value) - } - Call { func, args, destination, .. } => { - if let Some((destination, _)) = destination { - write!(fmt, "{:?} = ", destination)?; - } - write!(fmt, "{:?}(", func)?; - for (index, arg) in args.iter().enumerate() { - if index > 0 { - write!(fmt, ", ")?; - } - write!(fmt, "{:?}", arg)?; - } - write!(fmt, ")") - } - Assert { cond, expected, msg, .. } => { - write!(fmt, "assert(")?; - if !expected { - write!(fmt, "!")?; - } - write!(fmt, "{:?}, ", cond)?; - msg.fmt_assert_args(fmt)?; - write!(fmt, ")") - } - FalseEdge { .. } => write!(fmt, "falseEdge"), - FalseUnwind { .. } => write!(fmt, "falseUnwind"), - InlineAsm { template, ref operands, options, .. } => { - write!(fmt, "asm!(\"{}\"", InlineAsmTemplatePiece::to_string(template))?; - for op in operands { - write!(fmt, ", ")?; - let print_late = |&late| if late { "late" } else { "" }; - match op { - InlineAsmOperand::In { reg, value } => { - write!(fmt, "in({}) {:?}", reg, value)?; - } - InlineAsmOperand::Out { reg, late, place: Some(place) } => { - write!(fmt, "{}out({}) {:?}", print_late(late), reg, place)?; - } - InlineAsmOperand::Out { reg, late, place: None } => { - write!(fmt, "{}out({}) _", print_late(late), reg)?; - } - InlineAsmOperand::InOut { - reg, - late, - in_value, - out_place: Some(out_place), - } => { - write!( - fmt, - "in{}out({}) {:?} => {:?}", - print_late(late), - reg, - in_value, - out_place - )?; - } - InlineAsmOperand::InOut { reg, late, in_value, out_place: None } => { - write!(fmt, "in{}out({}) {:?} => _", print_late(late), reg, in_value)?; - } - InlineAsmOperand::Const { value } => { - write!(fmt, "const {:?}", value)?; - } - InlineAsmOperand::SymFn { value } => { - write!(fmt, "sym_fn {:?}", value)?; - } - InlineAsmOperand::SymStatic { def_id } => { - write!(fmt, "sym_static {:?}", def_id)?; - } - } - } - write!(fmt, ", options({:?}))", options) - } - } - } - - /// Returns the list of labels for the edges to the successor basic blocks. - pub fn fmt_successor_labels(&self) -> Vec> { - use self::TerminatorKind::*; - match *self { - Return | Resume | Abort | Unreachable | GeneratorDrop => vec![], - Goto { .. } => vec!["".into()], - SwitchInt { ref values, switch_ty, .. } => ty::tls::with(|tcx| { - let param_env = ty::ParamEnv::empty(); - let switch_ty = tcx.lift(&switch_ty).unwrap(); - let size = tcx.layout_of(param_env.and(switch_ty)).unwrap().size; - values - .iter() - .map(|&u| { - ty::Const::from_scalar(tcx, Scalar::from_uint(u, size), switch_ty) - .to_string() - .into() - }) - .chain(iter::once("otherwise".into())) - .collect() - }), - Call { destination: Some(_), cleanup: Some(_), .. } => { - vec!["return".into(), "unwind".into()] - } - Call { destination: Some(_), cleanup: None, .. } => vec!["return".into()], - Call { destination: None, cleanup: Some(_), .. } => vec!["unwind".into()], - Call { destination: None, cleanup: None, .. } => vec![], - Yield { drop: Some(_), .. } => vec!["resume".into(), "drop".into()], - Yield { drop: None, .. } => vec!["resume".into()], - DropAndReplace { unwind: None, .. } | Drop { unwind: None, .. } => { - vec!["return".into()] - } - DropAndReplace { unwind: Some(_), .. } | Drop { unwind: Some(_), .. } => { - vec!["return".into(), "unwind".into()] - } - Assert { cleanup: None, .. } => 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(_), .. } => vec!["".into()], - InlineAsm { destination: None, .. } => vec![], - } - } -} - /////////////////////////////////////////////////////////////////////////// // Statements