3578 lines
120 KiB
Rust
3578 lines
120 KiB
Rust
// ignore-tidy-filelength
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//! MIR datatypes and passes. See the [rustc guide] for more info.
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//!
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//! [rustc guide]: https://rust-lang.github.io/rustc-guide/mir/index.html
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use crate::hir::def::{CtorKind, Namespace};
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use crate::hir::def_id::DefId;
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use crate::hir::{self, InlineAsm as HirInlineAsm};
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use crate::mir::interpret::{ConstValue, InterpError, Scalar};
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use crate::mir::visit::MirVisitable;
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use rustc_data_structures::fx::FxHashSet;
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use rustc_data_structures::graph::dominators::{dominators, Dominators};
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use rustc_data_structures::graph::{self, GraphPredecessors, GraphSuccessors};
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use rustc_data_structures::indexed_vec::{Idx, IndexVec};
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use rustc_data_structures::sync::Lrc;
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use rustc_data_structures::sync::MappedReadGuard;
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use rustc_macros::HashStable;
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use crate::rustc_serialize::{self as serialize};
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use smallvec::SmallVec;
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use std::borrow::Cow;
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use std::fmt::{self, Debug, Formatter, Write, Display};
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use std::iter::FusedIterator;
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use std::ops::{Index, IndexMut};
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use std::slice;
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use std::vec::IntoIter;
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use std::{iter, mem, option, u32};
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use syntax::ast::Name;
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use syntax::symbol::{InternedString, Symbol};
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use syntax_pos::{Span, DUMMY_SP};
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use crate::ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
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use crate::ty::subst::{Subst, SubstsRef};
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use crate::ty::layout::VariantIdx;
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use crate::ty::{
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self, AdtDef, CanonicalUserTypeAnnotations, ClosureSubsts, GeneratorSubsts, Region, Ty, TyCtxt,
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UserTypeAnnotationIndex,
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};
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use crate::ty::print::{FmtPrinter, Printer};
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use crate::ty::adjustment::{PointerCast};
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pub use crate::mir::interpret::AssertMessage;
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mod cache;
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pub mod interpret;
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pub mod mono;
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pub mod tcx;
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pub mod traversal;
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pub mod visit;
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/// Types for locals
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type LocalDecls<'tcx> = IndexVec<Local, LocalDecl<'tcx>>;
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pub trait HasLocalDecls<'tcx> {
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fn local_decls(&self) -> &LocalDecls<'tcx>;
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}
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impl<'tcx> HasLocalDecls<'tcx> for LocalDecls<'tcx> {
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fn local_decls(&self) -> &LocalDecls<'tcx> {
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self
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}
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}
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impl<'tcx> HasLocalDecls<'tcx> for Body<'tcx> {
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fn local_decls(&self) -> &LocalDecls<'tcx> {
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&self.local_decls
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}
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}
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/// The various "big phases" that MIR goes through.
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///
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/// Warning: ordering of variants is significant
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#[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, PartialEq, Eq, PartialOrd, Ord)]
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pub enum MirPhase {
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Build = 0,
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Const = 1,
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Validated = 2,
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Optimized = 3,
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}
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impl MirPhase {
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/// Gets the index of the current MirPhase within the set of all MirPhases.
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pub fn phase_index(&self) -> usize {
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*self as usize
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}
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}
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/// Lowered representation of a single function.
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#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
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pub struct Body<'tcx> {
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/// List of basic blocks. References to basic block use a newtyped index type `BasicBlock`
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/// that indexes into this vector.
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basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
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/// Records how far through the "desugaring and optimization" process this particular
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/// MIR has traversed. This is particularly useful when inlining, since in that context
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/// we instantiate the promoted constants and add them to our promoted vector -- but those
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/// promoted items have already been optimized, whereas ours have not. This field allows
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/// us to see the difference and forego optimization on the inlined promoted items.
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pub phase: MirPhase,
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/// List of source scopes; these are referenced by statements
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/// and used for debuginfo. Indexed by a `SourceScope`.
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pub source_scopes: IndexVec<SourceScope, SourceScopeData>,
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/// Crate-local information for each source scope, that can't (and
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/// needn't) be tracked across crates.
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pub source_scope_local_data: ClearCrossCrate<IndexVec<SourceScope, SourceScopeLocalData>>,
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/// Rvalues promoted from this function, such as borrows of constants.
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/// Each of them is the Body of a constant with the fn's type parameters
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/// in scope, but a separate set of locals.
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pub promoted: IndexVec<Promoted, Body<'tcx>>,
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/// Yields type of the function, if it is a generator.
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pub yield_ty: Option<Ty<'tcx>>,
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/// Generator drop glue
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pub generator_drop: Option<Box<Body<'tcx>>>,
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/// The layout of a generator. Produced by the state transformation.
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pub generator_layout: Option<GeneratorLayout<'tcx>>,
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/// Declarations of locals.
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///
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/// The first local is the return value pointer, followed by `arg_count`
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/// locals for the function arguments, followed by any user-declared
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/// variables and temporaries.
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pub local_decls: LocalDecls<'tcx>,
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/// User type annotations
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pub user_type_annotations: CanonicalUserTypeAnnotations<'tcx>,
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/// Number of arguments this function takes.
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///
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/// Starting at local 1, `arg_count` locals will be provided by the caller
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/// and can be assumed to be initialized.
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///
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/// If this MIR was built for a constant, this will be 0.
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pub arg_count: usize,
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/// Mark an argument local (which must be a tuple) as getting passed as
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/// its individual components at the LLVM level.
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///
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/// This is used for the "rust-call" ABI.
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pub spread_arg: Option<Local>,
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/// Names and capture modes of all the closure upvars, assuming
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/// the first argument is either the closure or a reference to it.
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// NOTE(eddyb) This is *strictly* a temporary hack for codegen
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// debuginfo generation, and will be removed at some point.
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// Do **NOT** use it for anything else, upvar information should not be
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// in the MIR, please rely on local crate HIR or other side-channels.
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pub __upvar_debuginfo_codegen_only_do_not_use: Vec<UpvarDebuginfo>,
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/// Mark this MIR of a const context other than const functions as having converted a `&&` or
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/// `||` expression into `&` or `|` respectively. This is problematic because if we ever stop
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/// this conversion from happening and use short circuiting, we will cause the following code
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/// to change the value of `x`: `let mut x = 42; false && { x = 55; true };`
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///
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/// List of places where control flow was destroyed. Used for error reporting.
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pub control_flow_destroyed: Vec<(Span, String)>,
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/// A span representing this MIR, for error reporting
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pub span: Span,
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/// A cache for various calculations
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cache: cache::Cache,
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}
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impl<'tcx> Body<'tcx> {
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pub fn new(
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basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
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source_scopes: IndexVec<SourceScope, SourceScopeData>,
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source_scope_local_data: ClearCrossCrate<IndexVec<SourceScope, SourceScopeLocalData>>,
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promoted: IndexVec<Promoted, Body<'tcx>>,
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yield_ty: Option<Ty<'tcx>>,
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local_decls: LocalDecls<'tcx>,
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user_type_annotations: CanonicalUserTypeAnnotations<'tcx>,
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arg_count: usize,
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__upvar_debuginfo_codegen_only_do_not_use: Vec<UpvarDebuginfo>,
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span: Span,
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control_flow_destroyed: Vec<(Span, String)>,
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) -> Self {
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// We need `arg_count` locals, and one for the return place
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assert!(
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local_decls.len() >= arg_count + 1,
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"expected at least {} locals, got {}",
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arg_count + 1,
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local_decls.len()
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);
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Body {
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phase: MirPhase::Build,
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basic_blocks,
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source_scopes,
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source_scope_local_data,
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promoted,
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yield_ty,
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generator_drop: None,
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generator_layout: None,
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local_decls,
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user_type_annotations,
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arg_count,
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__upvar_debuginfo_codegen_only_do_not_use,
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spread_arg: None,
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span,
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cache: cache::Cache::new(),
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control_flow_destroyed,
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}
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}
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#[inline]
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pub fn basic_blocks(&self) -> &IndexVec<BasicBlock, BasicBlockData<'tcx>> {
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&self.basic_blocks
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}
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#[inline]
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pub fn basic_blocks_mut(&mut self) -> &mut IndexVec<BasicBlock, BasicBlockData<'tcx>> {
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self.cache.invalidate();
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&mut self.basic_blocks
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}
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#[inline]
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pub fn basic_blocks_and_local_decls_mut(
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&mut self,
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) -> (
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&mut IndexVec<BasicBlock, BasicBlockData<'tcx>>,
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&mut LocalDecls<'tcx>,
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) {
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self.cache.invalidate();
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(&mut self.basic_blocks, &mut self.local_decls)
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}
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#[inline]
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pub fn predecessors(&self) -> MappedReadGuard<'_, IndexVec<BasicBlock, Vec<BasicBlock>>> {
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self.cache.predecessors(self)
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}
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#[inline]
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pub fn predecessors_for(&self, bb: BasicBlock) -> MappedReadGuard<'_, Vec<BasicBlock>> {
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MappedReadGuard::map(self.predecessors(), |p| &p[bb])
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}
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#[inline]
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pub fn predecessor_locations(&self, loc: Location) -> impl Iterator<Item = Location> + '_ {
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let if_zero_locations = if loc.statement_index == 0 {
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let predecessor_blocks = self.predecessors_for(loc.block);
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let num_predecessor_blocks = predecessor_blocks.len();
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Some(
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(0..num_predecessor_blocks)
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.map(move |i| predecessor_blocks[i])
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.map(move |bb| self.terminator_loc(bb)),
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)
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} else {
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None
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};
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let if_not_zero_locations = if loc.statement_index == 0 {
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None
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} else {
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Some(Location {
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block: loc.block,
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statement_index: loc.statement_index - 1,
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})
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};
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if_zero_locations
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.into_iter()
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.flatten()
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.chain(if_not_zero_locations)
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}
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#[inline]
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pub fn dominators(&self) -> Dominators<BasicBlock> {
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dominators(self)
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}
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#[inline]
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pub fn local_kind(&self, local: Local) -> LocalKind {
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let index = local.as_usize();
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if index == 0 {
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debug_assert!(
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self.local_decls[local].mutability == Mutability::Mut,
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"return place should be mutable"
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);
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LocalKind::ReturnPointer
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} else if index < self.arg_count + 1 {
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LocalKind::Arg
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} else if self.local_decls[local].name.is_some() {
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LocalKind::Var
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} else {
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LocalKind::Temp
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}
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}
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/// Returns an iterator over all temporaries.
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#[inline]
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pub fn temps_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
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(self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
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let local = Local::new(index);
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if self.local_decls[local].is_user_variable.is_some() {
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None
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} else {
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Some(local)
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}
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})
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}
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/// Returns an iterator over all user-declared locals.
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#[inline]
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pub fn vars_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
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(self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
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let local = Local::new(index);
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if self.local_decls[local].is_user_variable.is_some() {
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Some(local)
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} else {
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None
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}
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})
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}
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/// Returns an iterator over all user-declared mutable locals.
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#[inline]
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pub fn mut_vars_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
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(self.arg_count + 1..self.local_decls.len()).filter_map(move |index| {
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let local = Local::new(index);
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let decl = &self.local_decls[local];
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if decl.is_user_variable.is_some() && decl.mutability == Mutability::Mut {
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Some(local)
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} else {
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None
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}
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})
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}
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/// Returns an iterator over all user-declared mutable arguments and locals.
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#[inline]
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pub fn mut_vars_and_args_iter<'a>(&'a self) -> impl Iterator<Item = Local> + 'a {
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(1..self.local_decls.len()).filter_map(move |index| {
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let local = Local::new(index);
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let decl = &self.local_decls[local];
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if (decl.is_user_variable.is_some() || index < self.arg_count + 1)
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&& decl.mutability == Mutability::Mut
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{
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Some(local)
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} else {
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None
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}
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})
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}
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/// Returns an iterator over all function arguments.
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#[inline]
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pub fn args_iter(&self) -> impl Iterator<Item = Local> {
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let arg_count = self.arg_count;
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(1..=arg_count).map(Local::new)
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}
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/// Returns an iterator over all user-defined variables and compiler-generated temporaries (all
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/// locals that are neither arguments nor the return place).
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#[inline]
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pub fn vars_and_temps_iter(&self) -> impl Iterator<Item = Local> {
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let arg_count = self.arg_count;
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let local_count = self.local_decls.len();
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(arg_count + 1..local_count).map(Local::new)
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}
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|
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/// Changes a statement to a nop. This is both faster than deleting instructions and avoids
|
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/// invalidating statement indices in `Location`s.
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pub fn make_statement_nop(&mut self, location: Location) {
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let block = &mut self[location.block];
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debug_assert!(location.statement_index < block.statements.len());
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block.statements[location.statement_index].make_nop()
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}
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|
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/// Returns the source info associated with `location`.
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pub fn source_info(&self, location: Location) -> &SourceInfo {
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let block = &self[location.block];
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let stmts = &block.statements;
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let idx = location.statement_index;
|
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if idx < stmts.len() {
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&stmts[idx].source_info
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} else {
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assert_eq!(idx, stmts.len());
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&block.terminator().source_info
|
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}
|
||
}
|
||
|
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/// Checks if `sub` is a sub scope of `sup`
|
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pub fn is_sub_scope(&self, mut sub: SourceScope, sup: SourceScope) -> bool {
|
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while sub != sup {
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match self.source_scopes[sub].parent_scope {
|
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None => return false,
|
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Some(p) => sub = p,
|
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}
|
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}
|
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true
|
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}
|
||
|
||
/// Returns the return type, it always return first element from `local_decls` array
|
||
pub fn return_ty(&self) -> Ty<'tcx> {
|
||
self.local_decls[RETURN_PLACE].ty
|
||
}
|
||
|
||
/// Gets the location of the terminator for the given block
|
||
pub fn terminator_loc(&self, bb: BasicBlock) -> Location {
|
||
Location {
|
||
block: bb,
|
||
statement_index: self[bb].statements.len(),
|
||
}
|
||
}
|
||
}
|
||
|
||
#[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub enum Safety {
|
||
Safe,
|
||
/// Unsafe because of a PushUnsafeBlock
|
||
BuiltinUnsafe,
|
||
/// Unsafe because of an unsafe fn
|
||
FnUnsafe,
|
||
/// Unsafe because of an `unsafe` block
|
||
ExplicitUnsafe(hir::HirId),
|
||
}
|
||
|
||
impl_stable_hash_for!(struct Body<'tcx> {
|
||
phase,
|
||
basic_blocks,
|
||
source_scopes,
|
||
source_scope_local_data,
|
||
promoted,
|
||
yield_ty,
|
||
generator_drop,
|
||
generator_layout,
|
||
local_decls,
|
||
user_type_annotations,
|
||
arg_count,
|
||
__upvar_debuginfo_codegen_only_do_not_use,
|
||
spread_arg,
|
||
control_flow_destroyed,
|
||
span,
|
||
cache
|
||
});
|
||
|
||
impl<'tcx> Index<BasicBlock> for Body<'tcx> {
|
||
type Output = BasicBlockData<'tcx>;
|
||
|
||
#[inline]
|
||
fn index(&self, index: BasicBlock) -> &BasicBlockData<'tcx> {
|
||
&self.basic_blocks()[index]
|
||
}
|
||
}
|
||
|
||
impl<'tcx> IndexMut<BasicBlock> for Body<'tcx> {
|
||
#[inline]
|
||
fn index_mut(&mut self, index: BasicBlock) -> &mut BasicBlockData<'tcx> {
|
||
&mut self.basic_blocks_mut()[index]
|
||
}
|
||
}
|
||
|
||
#[derive(Copy, Clone, Debug, HashStable)]
|
||
pub enum ClearCrossCrate<T> {
|
||
Clear,
|
||
Set(T),
|
||
}
|
||
|
||
impl<T> ClearCrossCrate<T> {
|
||
pub fn assert_crate_local(self) -> T {
|
||
match self {
|
||
ClearCrossCrate::Clear => bug!("unwrapping cross-crate data"),
|
||
ClearCrossCrate::Set(v) => v,
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<T: serialize::Encodable> serialize::UseSpecializedEncodable for ClearCrossCrate<T> {}
|
||
impl<T: serialize::Decodable> serialize::UseSpecializedDecodable for ClearCrossCrate<T> {}
|
||
|
||
/// Grouped information about the source code origin of a MIR entity.
|
||
/// Intended to be inspected by diagnostics and debuginfo.
|
||
/// Most passes can work with it as a whole, within a single function.
|
||
#[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, HashStable)]
|
||
pub struct SourceInfo {
|
||
/// Source span for the AST pertaining to this MIR entity.
|
||
pub span: Span,
|
||
|
||
/// The source scope, keeping track of which bindings can be
|
||
/// seen by debuginfo, active lint levels, `unsafe {...}`, etc.
|
||
pub scope: SourceScope,
|
||
}
|
||
|
||
///////////////////////////////////////////////////////////////////////////
|
||
// Mutability and borrow kinds
|
||
|
||
#[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub enum Mutability {
|
||
Mut,
|
||
Not,
|
||
}
|
||
|
||
impl From<Mutability> for hir::Mutability {
|
||
fn from(m: Mutability) -> Self {
|
||
match m {
|
||
Mutability::Mut => hir::MutMutable,
|
||
Mutability::Not => hir::MutImmutable,
|
||
}
|
||
}
|
||
}
|
||
|
||
#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd,
|
||
Ord, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub enum BorrowKind {
|
||
/// Data must be immutable and is aliasable.
|
||
Shared,
|
||
|
||
/// The immediately borrowed place must be immutable, but projections from
|
||
/// it don't need to be. For example, a shallow borrow of `a.b` doesn't
|
||
/// conflict with a mutable borrow of `a.b.c`.
|
||
///
|
||
/// This is used when lowering matches: when matching on a place we want to
|
||
/// ensure that place have the same value from the start of the match until
|
||
/// an arm is selected. This prevents this code from compiling:
|
||
///
|
||
/// let mut x = &Some(0);
|
||
/// match *x {
|
||
/// None => (),
|
||
/// Some(_) if { x = &None; false } => (),
|
||
/// Some(_) => (),
|
||
/// }
|
||
///
|
||
/// This can't be a shared borrow because mutably borrowing (*x as Some).0
|
||
/// should not prevent `if let None = x { ... }`, for example, because the
|
||
/// mutating `(*x as Some).0` can't affect the discriminant of `x`.
|
||
/// We can also report errors with this kind of borrow differently.
|
||
Shallow,
|
||
|
||
/// Data must be immutable but not aliasable. This kind of borrow
|
||
/// cannot currently be expressed by the user and is used only in
|
||
/// implicit closure bindings. It is needed when the closure is
|
||
/// borrowing or mutating a mutable referent, e.g.:
|
||
///
|
||
/// let x: &mut isize = ...;
|
||
/// let y = || *x += 5;
|
||
///
|
||
/// If we were to try to translate this closure into a more explicit
|
||
/// form, we'd encounter an error with the code as written:
|
||
///
|
||
/// struct Env { x: & &mut isize }
|
||
/// let x: &mut isize = ...;
|
||
/// let y = (&mut Env { &x }, fn_ptr); // Closure is pair of env and fn
|
||
/// fn fn_ptr(env: &mut Env) { **env.x += 5; }
|
||
///
|
||
/// This is then illegal because you cannot mutate an `&mut` found
|
||
/// in an aliasable location. To solve, you'd have to translate with
|
||
/// an `&mut` borrow:
|
||
///
|
||
/// struct Env { x: & &mut isize }
|
||
/// let x: &mut isize = ...;
|
||
/// let y = (&mut Env { &mut x }, fn_ptr); // changed from &x to &mut x
|
||
/// fn fn_ptr(env: &mut Env) { **env.x += 5; }
|
||
///
|
||
/// Now the assignment to `**env.x` is legal, but creating a
|
||
/// mutable pointer to `x` is not because `x` is not mutable. We
|
||
/// could fix this by declaring `x` as `let mut x`. This is ok in
|
||
/// user code, if awkward, but extra weird for closures, since the
|
||
/// borrow is hidden.
|
||
///
|
||
/// So we introduce a "unique imm" borrow -- the referent is
|
||
/// immutable, but not aliasable. This solves the problem. For
|
||
/// simplicity, we don't give users the way to express this
|
||
/// borrow, it's just used when translating closures.
|
||
Unique,
|
||
|
||
/// Data is mutable and not aliasable.
|
||
Mut {
|
||
/// `true` if this borrow arose from method-call auto-ref
|
||
/// (i.e., `adjustment::Adjust::Borrow`).
|
||
allow_two_phase_borrow: bool,
|
||
},
|
||
}
|
||
|
||
impl BorrowKind {
|
||
pub fn allows_two_phase_borrow(&self) -> bool {
|
||
match *self {
|
||
BorrowKind::Shared | BorrowKind::Shallow | BorrowKind::Unique => false,
|
||
BorrowKind::Mut { allow_two_phase_borrow } => allow_two_phase_borrow,
|
||
}
|
||
}
|
||
}
|
||
|
||
///////////////////////////////////////////////////////////////////////////
|
||
// Variables and temps
|
||
|
||
newtype_index! {
|
||
pub struct Local {
|
||
derive [HashStable]
|
||
DEBUG_FORMAT = "_{}",
|
||
const RETURN_PLACE = 0,
|
||
}
|
||
}
|
||
|
||
/// Classifies locals into categories. See `Body::local_kind`.
|
||
#[derive(PartialEq, Eq, Debug, HashStable)]
|
||
pub enum LocalKind {
|
||
/// User-declared variable binding
|
||
Var,
|
||
/// Compiler-introduced temporary
|
||
Temp,
|
||
/// Function argument
|
||
Arg,
|
||
/// Location of function's return value
|
||
ReturnPointer,
|
||
}
|
||
|
||
#[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
|
||
pub struct VarBindingForm<'tcx> {
|
||
/// Is variable bound via `x`, `mut x`, `ref x`, or `ref mut x`?
|
||
pub binding_mode: ty::BindingMode,
|
||
/// If an explicit type was provided for this variable binding,
|
||
/// this holds the source Span of that type.
|
||
///
|
||
/// NOTE: if you want to change this to a `HirId`, be wary that
|
||
/// doing so breaks incremental compilation (as of this writing),
|
||
/// while a `Span` does not cause our tests to fail.
|
||
pub opt_ty_info: Option<Span>,
|
||
/// Place of the RHS of the =, or the subject of the `match` where this
|
||
/// variable is initialized. None in the case of `let PATTERN;`.
|
||
/// Some((None, ..)) in the case of and `let [mut] x = ...` because
|
||
/// (a) the right-hand side isn't evaluated as a place expression.
|
||
/// (b) it gives a way to separate this case from the remaining cases
|
||
/// for diagnostics.
|
||
pub opt_match_place: Option<(Option<Place<'tcx>>, Span)>,
|
||
/// Span of the pattern in which this variable was bound.
|
||
pub pat_span: Span,
|
||
}
|
||
|
||
#[derive(Clone, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
|
||
pub enum BindingForm<'tcx> {
|
||
/// This is a binding for a non-`self` binding, or a `self` that has an explicit type.
|
||
Var(VarBindingForm<'tcx>),
|
||
/// Binding for a `self`/`&self`/`&mut self` binding where the type is implicit.
|
||
ImplicitSelf(ImplicitSelfKind),
|
||
/// Reference used in a guard expression to ensure immutability.
|
||
RefForGuard,
|
||
}
|
||
|
||
/// Represents what type of implicit self a function has, if any.
|
||
#[derive(Clone, Copy, PartialEq, Eq, Hash, Debug, RustcEncodable, RustcDecodable)]
|
||
pub enum ImplicitSelfKind {
|
||
/// Represents a `fn x(self);`.
|
||
Imm,
|
||
/// Represents a `fn x(mut self);`.
|
||
Mut,
|
||
/// Represents a `fn x(&self);`.
|
||
ImmRef,
|
||
/// Represents a `fn x(&mut self);`.
|
||
MutRef,
|
||
/// Represents when a function does not have a self argument or
|
||
/// when a function has a `self: X` argument.
|
||
None
|
||
}
|
||
|
||
CloneTypeFoldableAndLiftImpls! { BindingForm<'tcx>, }
|
||
|
||
impl_stable_hash_for!(struct self::VarBindingForm<'tcx> {
|
||
binding_mode,
|
||
opt_ty_info,
|
||
opt_match_place,
|
||
pat_span
|
||
});
|
||
|
||
impl_stable_hash_for!(enum self::ImplicitSelfKind {
|
||
Imm,
|
||
Mut,
|
||
ImmRef,
|
||
MutRef,
|
||
None
|
||
});
|
||
|
||
impl_stable_hash_for!(enum self::MirPhase {
|
||
Build,
|
||
Const,
|
||
Validated,
|
||
Optimized,
|
||
});
|
||
|
||
mod binding_form_impl {
|
||
use crate::ich::StableHashingContext;
|
||
use rustc_data_structures::stable_hasher::{HashStable, StableHasher, StableHasherResult};
|
||
|
||
impl<'a, 'tcx> HashStable<StableHashingContext<'a>> for super::BindingForm<'tcx> {
|
||
fn hash_stable<W: StableHasherResult>(
|
||
&self,
|
||
hcx: &mut StableHashingContext<'a>,
|
||
hasher: &mut StableHasher<W>,
|
||
) {
|
||
use super::BindingForm::*;
|
||
::std::mem::discriminant(self).hash_stable(hcx, hasher);
|
||
|
||
match self {
|
||
Var(binding) => binding.hash_stable(hcx, hasher),
|
||
ImplicitSelf(kind) => kind.hash_stable(hcx, hasher),
|
||
RefForGuard => (),
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
/// `BlockTailInfo` is attached to the `LocalDecl` for temporaries
|
||
/// created during evaluation of expressions in a block tail
|
||
/// expression; that is, a block like `{ STMT_1; STMT_2; EXPR }`.
|
||
///
|
||
/// It is used to improve diagnostics when such temporaries are
|
||
/// involved in borrow_check errors, e.g., explanations of where the
|
||
/// temporaries come from, when their destructors are run, and/or how
|
||
/// one might revise the code to satisfy the borrow checker's rules.
|
||
#[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
|
||
pub struct BlockTailInfo {
|
||
/// If `true`, then the value resulting from evaluating this tail
|
||
/// expression is ignored by the block's expression context.
|
||
///
|
||
/// Examples include `{ ...; tail };` and `let _ = { ...; tail };`
|
||
/// but not e.g., `let _x = { ...; tail };`
|
||
pub tail_result_is_ignored: bool,
|
||
}
|
||
|
||
impl_stable_hash_for!(struct BlockTailInfo { tail_result_is_ignored });
|
||
|
||
/// A MIR local.
|
||
///
|
||
/// This can be a binding declared by the user, a temporary inserted by the compiler, a function
|
||
/// argument, or the return place.
|
||
#[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub struct LocalDecl<'tcx> {
|
||
/// `let mut x` vs `let x`.
|
||
///
|
||
/// Temporaries and the return place are always mutable.
|
||
pub mutability: Mutability,
|
||
|
||
/// Some(binding_mode) if this corresponds to a user-declared local variable.
|
||
///
|
||
/// This is solely used for local diagnostics when generating
|
||
/// warnings/errors when compiling the current crate, and
|
||
/// therefore it need not be visible across crates. pnkfelix
|
||
/// currently hypothesized we *need* to wrap this in a
|
||
/// `ClearCrossCrate` as long as it carries as `HirId`.
|
||
pub is_user_variable: Option<ClearCrossCrate<BindingForm<'tcx>>>,
|
||
|
||
/// `true` if this is an internal local.
|
||
///
|
||
/// These locals are not based on types in the source code and are only used
|
||
/// for a few desugarings at the moment.
|
||
///
|
||
/// The generator transformation will sanity check the locals which are live
|
||
/// across a suspension point against the type components of the generator
|
||
/// which type checking knows are live across a suspension point. We need to
|
||
/// flag drop flags to avoid triggering this check as they are introduced
|
||
/// after typeck.
|
||
///
|
||
/// Unsafety checking will also ignore dereferences of these locals,
|
||
/// so they can be used for raw pointers only used in a desugaring.
|
||
///
|
||
/// This should be sound because the drop flags are fully algebraic, and
|
||
/// therefore don't affect the OIBIT or outlives properties of the
|
||
/// generator.
|
||
pub internal: bool,
|
||
|
||
/// If this local is a temporary and `is_block_tail` is `Some`,
|
||
/// then it is a temporary created for evaluation of some
|
||
/// subexpression of some block's tail expression (with no
|
||
/// intervening statement context).
|
||
pub is_block_tail: Option<BlockTailInfo>,
|
||
|
||
/// Type of this local.
|
||
pub ty: Ty<'tcx>,
|
||
|
||
/// If the user manually ascribed a type to this variable,
|
||
/// e.g., via `let x: T`, then we carry that type here. The MIR
|
||
/// borrow checker needs this information since it can affect
|
||
/// region inference.
|
||
pub user_ty: UserTypeProjections,
|
||
|
||
/// Name of the local, used in debuginfo and pretty-printing.
|
||
///
|
||
/// Note that function arguments can also have this set to `Some(_)`
|
||
/// to generate better debuginfo.
|
||
pub name: Option<Name>,
|
||
|
||
/// The *syntactic* (i.e., not visibility) source scope the local is defined
|
||
/// in. If the local was defined in a let-statement, this
|
||
/// is *within* the let-statement, rather than outside
|
||
/// of it.
|
||
///
|
||
/// This is needed because the visibility source scope of locals within
|
||
/// a let-statement is weird.
|
||
///
|
||
/// The reason is that we want the local to be *within* the let-statement
|
||
/// for lint purposes, but we want the local to be *after* the let-statement
|
||
/// for names-in-scope purposes.
|
||
///
|
||
/// That's it, if we have a let-statement like the one in this
|
||
/// function:
|
||
///
|
||
/// ```
|
||
/// fn foo(x: &str) {
|
||
/// #[allow(unused_mut)]
|
||
/// let mut x: u32 = { // <- one unused mut
|
||
/// let mut y: u32 = x.parse().unwrap();
|
||
/// y + 2
|
||
/// };
|
||
/// drop(x);
|
||
/// }
|
||
/// ```
|
||
///
|
||
/// Then, from a lint point of view, the declaration of `x: u32`
|
||
/// (and `y: u32`) are within the `#[allow(unused_mut)]` scope - the
|
||
/// lint scopes are the same as the AST/HIR nesting.
|
||
///
|
||
/// However, from a name lookup point of view, the scopes look more like
|
||
/// as if the let-statements were `match` expressions:
|
||
///
|
||
/// ```
|
||
/// fn foo(x: &str) {
|
||
/// match {
|
||
/// match x.parse().unwrap() {
|
||
/// y => y + 2
|
||
/// }
|
||
/// } {
|
||
/// x => drop(x)
|
||
/// };
|
||
/// }
|
||
/// ```
|
||
///
|
||
/// We care about the name-lookup scopes for debuginfo - if the
|
||
/// debuginfo instruction pointer is at the call to `x.parse()`, we
|
||
/// want `x` to refer to `x: &str`, but if it is at the call to
|
||
/// `drop(x)`, we want it to refer to `x: u32`.
|
||
///
|
||
/// To allow both uses to work, we need to have more than a single scope
|
||
/// for a local. We have the `source_info.scope` represent the
|
||
/// "syntactic" lint scope (with a variable being under its let
|
||
/// block) while the `visibility_scope` represents the "local variable"
|
||
/// scope (where the "rest" of a block is under all prior let-statements).
|
||
///
|
||
/// The end result looks like this:
|
||
///
|
||
/// ```text
|
||
/// ROOT SCOPE
|
||
/// │{ argument x: &str }
|
||
/// │
|
||
/// │ │{ #[allow(unused_mut)] } // this is actually split into 2 scopes
|
||
/// │ │ // in practice because I'm lazy.
|
||
/// │ │
|
||
/// │ │← x.source_info.scope
|
||
/// │ │← `x.parse().unwrap()`
|
||
/// │ │
|
||
/// │ │ │← y.source_info.scope
|
||
/// │ │
|
||
/// │ │ │{ let y: u32 }
|
||
/// │ │ │
|
||
/// │ │ │← y.visibility_scope
|
||
/// │ │ │← `y + 2`
|
||
/// │
|
||
/// │ │{ let x: u32 }
|
||
/// │ │← x.visibility_scope
|
||
/// │ │← `drop(x)` // this accesses `x: u32`
|
||
/// ```
|
||
pub source_info: SourceInfo,
|
||
|
||
/// Source scope within which the local is visible (for debuginfo)
|
||
/// (see `source_info` for more details).
|
||
pub visibility_scope: SourceScope,
|
||
}
|
||
|
||
impl<'tcx> LocalDecl<'tcx> {
|
||
/// Returns `true` only if local is a binding that can itself be
|
||
/// made mutable via the addition of the `mut` keyword, namely
|
||
/// something like the occurrences of `x` in:
|
||
/// - `fn foo(x: Type) { ... }`,
|
||
/// - `let x = ...`,
|
||
/// - or `match ... { C(x) => ... }`
|
||
pub fn can_be_made_mutable(&self) -> bool {
|
||
match self.is_user_variable {
|
||
Some(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
|
||
binding_mode: ty::BindingMode::BindByValue(_),
|
||
opt_ty_info: _,
|
||
opt_match_place: _,
|
||
pat_span: _,
|
||
}))) => true,
|
||
|
||
Some(ClearCrossCrate::Set(BindingForm::ImplicitSelf(ImplicitSelfKind::Imm)))
|
||
=> true,
|
||
|
||
_ => false,
|
||
}
|
||
}
|
||
|
||
/// Returns `true` if local is definitely not a `ref ident` or
|
||
/// `ref mut ident` binding. (Such bindings cannot be made into
|
||
/// mutable bindings, but the inverse does not necessarily hold).
|
||
pub fn is_nonref_binding(&self) -> bool {
|
||
match self.is_user_variable {
|
||
Some(ClearCrossCrate::Set(BindingForm::Var(VarBindingForm {
|
||
binding_mode: ty::BindingMode::BindByValue(_),
|
||
opt_ty_info: _,
|
||
opt_match_place: _,
|
||
pat_span: _,
|
||
}))) => true,
|
||
|
||
Some(ClearCrossCrate::Set(BindingForm::ImplicitSelf(_))) => true,
|
||
|
||
_ => false,
|
||
}
|
||
}
|
||
|
||
/// Returns `true` is the local is from a compiler desugaring, e.g.,
|
||
/// `__next` from a `for` loop.
|
||
#[inline]
|
||
pub fn from_compiler_desugaring(&self) -> bool {
|
||
self.source_info.span.compiler_desugaring_kind().is_some()
|
||
}
|
||
|
||
/// Creates a new `LocalDecl` for a temporary.
|
||
#[inline]
|
||
pub fn new_temp(ty: Ty<'tcx>, span: Span) -> Self {
|
||
Self::new_local(ty, Mutability::Mut, false, span)
|
||
}
|
||
|
||
/// Converts `self` into same `LocalDecl` except tagged as immutable.
|
||
#[inline]
|
||
pub fn immutable(mut self) -> Self {
|
||
self.mutability = Mutability::Not;
|
||
self
|
||
}
|
||
|
||
/// Converts `self` into same `LocalDecl` except tagged as internal temporary.
|
||
#[inline]
|
||
pub fn block_tail(mut self, info: BlockTailInfo) -> Self {
|
||
assert!(self.is_block_tail.is_none());
|
||
self.is_block_tail = Some(info);
|
||
self
|
||
}
|
||
|
||
/// Creates a new `LocalDecl` for a internal temporary.
|
||
#[inline]
|
||
pub fn new_internal(ty: Ty<'tcx>, span: Span) -> Self {
|
||
Self::new_local(ty, Mutability::Mut, true, span)
|
||
}
|
||
|
||
#[inline]
|
||
fn new_local(
|
||
ty: Ty<'tcx>,
|
||
mutability: Mutability,
|
||
internal: bool,
|
||
span: Span,
|
||
) -> Self {
|
||
LocalDecl {
|
||
mutability,
|
||
ty,
|
||
user_ty: UserTypeProjections::none(),
|
||
name: None,
|
||
source_info: SourceInfo {
|
||
span,
|
||
scope: OUTERMOST_SOURCE_SCOPE,
|
||
},
|
||
visibility_scope: OUTERMOST_SOURCE_SCOPE,
|
||
internal,
|
||
is_user_variable: None,
|
||
is_block_tail: None,
|
||
}
|
||
}
|
||
|
||
/// Builds a `LocalDecl` for the return place.
|
||
///
|
||
/// This must be inserted into the `local_decls` list as the first local.
|
||
#[inline]
|
||
pub fn new_return_place(return_ty: Ty<'_>, span: Span) -> LocalDecl<'_> {
|
||
LocalDecl {
|
||
mutability: Mutability::Mut,
|
||
ty: return_ty,
|
||
user_ty: UserTypeProjections::none(),
|
||
source_info: SourceInfo {
|
||
span,
|
||
scope: OUTERMOST_SOURCE_SCOPE,
|
||
},
|
||
visibility_scope: OUTERMOST_SOURCE_SCOPE,
|
||
internal: false,
|
||
is_block_tail: None,
|
||
name: None, // FIXME maybe we do want some name here?
|
||
is_user_variable: None,
|
||
}
|
||
}
|
||
}
|
||
|
||
/// A closure capture, with its name and mode.
|
||
#[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub struct UpvarDebuginfo {
|
||
pub debug_name: Name,
|
||
|
||
/// If true, the capture is behind a reference.
|
||
pub by_ref: bool,
|
||
}
|
||
|
||
///////////////////////////////////////////////////////////////////////////
|
||
// BasicBlock
|
||
|
||
newtype_index! {
|
||
pub struct BasicBlock {
|
||
derive [HashStable]
|
||
DEBUG_FORMAT = "bb{}",
|
||
const START_BLOCK = 0,
|
||
}
|
||
}
|
||
|
||
impl BasicBlock {
|
||
pub fn start_location(self) -> Location {
|
||
Location {
|
||
block: self,
|
||
statement_index: 0,
|
||
}
|
||
}
|
||
}
|
||
|
||
///////////////////////////////////////////////////////////////////////////
|
||
// BasicBlockData and Terminator
|
||
|
||
#[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub struct BasicBlockData<'tcx> {
|
||
/// List of statements in this block.
|
||
pub statements: Vec<Statement<'tcx>>,
|
||
|
||
/// Terminator for this block.
|
||
///
|
||
/// N.B., this should generally ONLY be `None` during construction.
|
||
/// Therefore, you should generally access it via the
|
||
/// `terminator()` or `terminator_mut()` methods. The only
|
||
/// exception is that certain passes, such as `simplify_cfg`, swap
|
||
/// out the terminator temporarily with `None` while they continue
|
||
/// to recurse over the set of basic blocks.
|
||
pub terminator: Option<Terminator<'tcx>>,
|
||
|
||
/// If true, this block lies on an unwind path. This is used
|
||
/// during codegen where distinct kinds of basic blocks may be
|
||
/// generated (particularly for MSVC cleanup). Unwind blocks must
|
||
/// only branch to other unwind blocks.
|
||
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)]
|
||
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 {
|
||
/// discriminant value being tested
|
||
discr: Operand<'tcx>,
|
||
|
||
/// type of value being tested
|
||
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<BasicBlock> // 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<BasicBlock>,
|
||
},
|
||
|
||
/// 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 by now. This should occur at most once.
|
||
Return,
|
||
|
||
/// Indicates a terminator that can never be reached.
|
||
Unreachable,
|
||
|
||
/// Drop the Place
|
||
Drop {
|
||
location: Place<'tcx>,
|
||
target: BasicBlock,
|
||
unwind: Option<BasicBlock>,
|
||
},
|
||
|
||
/// 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 {
|
||
location: Place<'tcx>,
|
||
value: Operand<'tcx>,
|
||
target: BasicBlock,
|
||
unwind: Option<BasicBlock>,
|
||
},
|
||
|
||
/// 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<Operand<'tcx>>,
|
||
/// 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<BasicBlock>,
|
||
/// Whether this is from a call in HIR, rather than from an overloaded
|
||
/// operator. True for overloaded function call.
|
||
from_hir_call: bool,
|
||
},
|
||
|
||
/// 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<BasicBlock>,
|
||
},
|
||
|
||
/// A suspend point
|
||
Yield {
|
||
/// The value to return
|
||
value: Operand<'tcx>,
|
||
/// Where to resume to
|
||
resume: BasicBlock,
|
||
/// Cleanup to be done if the generator is dropped at this suspend point
|
||
drop: Option<BasicBlock>,
|
||
},
|
||
|
||
/// 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.
|
||
FalseEdges {
|
||
/// The target normal control flow will take
|
||
real_target: BasicBlock,
|
||
/// The list of blocks control flow could conceptually take, but won't
|
||
/// in practice
|
||
imaginary_targets: Vec<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<BasicBlock>,
|
||
},
|
||
}
|
||
|
||
pub type Successors<'a> =
|
||
iter::Chain<option::IntoIter<&'a BasicBlock>, slice::Iter<'a, BasicBlock>>;
|
||
pub type SuccessorsMut<'a> =
|
||
iter::Chain<option::IntoIter<&'a mut BasicBlock>, 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<BasicBlock>> {
|
||
self.kind.unwind()
|
||
}
|
||
|
||
pub fn unwind_mut(&mut self) -> Option<&mut Option<BasicBlock>> {
|
||
self.kind.unwind_mut()
|
||
}
|
||
}
|
||
|
||
impl<'tcx> TerminatorKind<'tcx> {
|
||
pub fn if_<'a, 'gcx>(
|
||
tcx: TyCtxt<'a, 'gcx, 'tcx>,
|
||
cond: Operand<'tcx>,
|
||
t: BasicBlock,
|
||
f: BasicBlock,
|
||
) -> TerminatorKind<'tcx> {
|
||
static BOOL_SWITCH_FALSE: &'static [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,
|
||
..
|
||
} => 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,
|
||
} => 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[..]),
|
||
FalseEdges {
|
||
ref real_target,
|
||
ref imaginary_targets,
|
||
} => Some(real_target).into_iter().chain(&imaginary_targets[..]),
|
||
}
|
||
}
|
||
|
||
pub fn successors_mut(&mut self) -> SuccessorsMut<'_> {
|
||
use self::TerminatorKind::*;
|
||
match *self {
|
||
Resume
|
||
| Abort
|
||
| GeneratorDrop
|
||
| Return
|
||
| Unreachable
|
||
| Call {
|
||
destination: None,
|
||
cleanup: 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,
|
||
} => 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[..]),
|
||
FalseEdges {
|
||
ref mut real_target,
|
||
ref mut imaginary_targets,
|
||
} => Some(real_target)
|
||
.into_iter()
|
||
.chain(&mut imaginary_targets[..]),
|
||
}
|
||
}
|
||
|
||
pub fn unwind(&self) -> Option<&Option<BasicBlock>> {
|
||
match *self {
|
||
TerminatorKind::Goto { .. }
|
||
| TerminatorKind::Resume
|
||
| TerminatorKind::Abort
|
||
| TerminatorKind::Return
|
||
| TerminatorKind::Unreachable
|
||
| TerminatorKind::GeneratorDrop
|
||
| TerminatorKind::Yield { .. }
|
||
| TerminatorKind::SwitchInt { .. }
|
||
| TerminatorKind::FalseEdges { .. } => 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<BasicBlock>> {
|
||
match *self {
|
||
TerminatorKind::Goto { .. }
|
||
| TerminatorKind::Resume
|
||
| TerminatorKind::Abort
|
||
| TerminatorKind::Return
|
||
| TerminatorKind::Unreachable
|
||
| TerminatorKind::GeneratorDrop
|
||
| TerminatorKind::Yield { .. }
|
||
| TerminatorKind::SwitchInt { .. }
|
||
| TerminatorKind::FalseEdges { .. } => 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<Terminator<'tcx>>) -> BasicBlockData<'tcx> {
|
||
BasicBlockData {
|
||
statements: vec![],
|
||
terminator,
|
||
is_cleanup: false,
|
||
}
|
||
}
|
||
|
||
/// Accessor for terminator.
|
||
///
|
||
/// Terminator may not be None after construction of the basic block is complete. This accessor
|
||
/// provides a convenience way to reach the terminator.
|
||
pub fn terminator(&self) -> &Terminator<'tcx> {
|
||
self.terminator.as_ref().expect("invalid terminator state")
|
||
}
|
||
|
||
pub fn terminator_mut(&mut self) -> &mut Terminator<'tcx> {
|
||
self.terminator.as_mut().expect("invalid terminator state")
|
||
}
|
||
|
||
pub fn retain_statements<F>(&mut self, mut f: F)
|
||
where
|
||
F: FnMut(&mut Statement<'_>) -> bool,
|
||
{
|
||
for s in &mut self.statements {
|
||
if !f(s) {
|
||
s.make_nop();
|
||
}
|
||
}
|
||
}
|
||
|
||
pub fn expand_statements<F, I>(&mut self, mut f: F)
|
||
where
|
||
F: FnMut(&mut Statement<'tcx>) -> Option<I>,
|
||
I: iter::TrustedLen<Item = Statement<'tcx>>,
|
||
{
|
||
// Gather all the iterators we'll need to splice in, and their positions.
|
||
let mut splices: Vec<(usize, I)> = vec![];
|
||
let mut extra_stmts = 0;
|
||
for (i, s) in self.statements.iter_mut().enumerate() {
|
||
if let Some(mut new_stmts) = f(s) {
|
||
if let Some(first) = new_stmts.next() {
|
||
// We can already store the first new statement.
|
||
*s = first;
|
||
|
||
// Save the other statements for optimized splicing.
|
||
let remaining = new_stmts.size_hint().0;
|
||
if remaining > 0 {
|
||
splices.push((i + 1 + extra_stmts, new_stmts));
|
||
extra_stmts += remaining;
|
||
}
|
||
} else {
|
||
s.make_nop();
|
||
}
|
||
}
|
||
}
|
||
|
||
// Splice in the new statements, from the end of the block.
|
||
// FIXME(eddyb) This could be more efficient with a "gap buffer"
|
||
// where a range of elements ("gap") is left uninitialized, with
|
||
// splicing adding new elements to the end of that gap and moving
|
||
// existing elements from before the gap to the end of the gap.
|
||
// For now, this is safe code, emulating a gap but initializing it.
|
||
let mut gap = self.statements.len()..self.statements.len() + extra_stmts;
|
||
self.statements.resize(
|
||
gap.end,
|
||
Statement {
|
||
source_info: SourceInfo {
|
||
span: DUMMY_SP,
|
||
scope: OUTERMOST_SOURCE_SCOPE,
|
||
},
|
||
kind: StatementKind::Nop,
|
||
},
|
||
);
|
||
for (splice_start, new_stmts) in splices.into_iter().rev() {
|
||
let splice_end = splice_start + new_stmts.size_hint().0;
|
||
while gap.end > splice_end {
|
||
gap.start -= 1;
|
||
gap.end -= 1;
|
||
self.statements.swap(gap.start, gap.end);
|
||
}
|
||
self.statements.splice(splice_start..splice_end, new_stmts);
|
||
gap.end = splice_start;
|
||
}
|
||
}
|
||
|
||
pub fn visitable(&self, index: usize) -> &dyn MirVisitable<'tcx> {
|
||
if index < self.statements.len() {
|
||
&self.statements[index]
|
||
} else {
|
||
&self.terminator
|
||
}
|
||
}
|
||
}
|
||
|
||
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().nth(0).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> {
|
||
/// Write 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<W: Write>(&self, fmt: &mut W) -> fmt::Result {
|
||
use self::TerminatorKind::*;
|
||
match *self {
|
||
Goto { .. } => write!(fmt, "goto"),
|
||
SwitchInt {
|
||
discr: ref place, ..
|
||
} => write!(fmt, "switchInt({:?})", place),
|
||
Return => write!(fmt, "return"),
|
||
GeneratorDrop => write!(fmt, "generator_drop"),
|
||
Resume => write!(fmt, "resume"),
|
||
Abort => write!(fmt, "abort"),
|
||
Yield { ref value, .. } => write!(fmt, "_1 = suspend({:?})", value),
|
||
Unreachable => write!(fmt, "unreachable"),
|
||
Drop { ref location, .. } => write!(fmt, "drop({:?})", location),
|
||
DropAndReplace {
|
||
ref location,
|
||
ref value,
|
||
..
|
||
} => write!(fmt, "replace({:?} <- {:?})", location, value),
|
||
Call {
|
||
ref func,
|
||
ref args,
|
||
ref destination,
|
||
..
|
||
} => {
|
||
if let Some((ref 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 {
|
||
ref cond,
|
||
expected,
|
||
ref msg,
|
||
..
|
||
} => {
|
||
write!(fmt, "assert(")?;
|
||
if !expected {
|
||
write!(fmt, "!")?;
|
||
}
|
||
write!(fmt, "{:?}, \"{:?}\")", cond, msg)
|
||
}
|
||
FalseEdges { .. } => write!(fmt, "falseEdges"),
|
||
FalseUnwind { .. } => write!(fmt, "falseUnwind"),
|
||
}
|
||
}
|
||
|
||
/// Returns the list of labels for the edges to the successor basic blocks.
|
||
pub fn fmt_successor_labels(&self) -> Vec<Cow<'static, str>> {
|
||
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_to_global(&switch_ty).unwrap();
|
||
let size = tcx.layout_of(param_env.and(switch_ty)).unwrap().size;
|
||
values
|
||
.iter()
|
||
.map(|&u| {
|
||
tcx.mk_const(ty::Const {
|
||
val: ConstValue::Scalar(
|
||
Scalar::from_uint(u, size).into(),
|
||
),
|
||
ty: 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()],
|
||
FalseEdges {
|
||
ref imaginary_targets,
|
||
..
|
||
} => {
|
||
let mut l = vec!["real".into()];
|
||
l.resize(imaginary_targets.len() + 1, "imaginary".into());
|
||
l
|
||
}
|
||
FalseUnwind {
|
||
unwind: Some(_), ..
|
||
} => vec!["real".into(), "cleanup".into()],
|
||
FalseUnwind { unwind: None, .. } => vec!["real".into()],
|
||
}
|
||
}
|
||
}
|
||
|
||
///////////////////////////////////////////////////////////////////////////
|
||
// Statements
|
||
|
||
#[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub struct Statement<'tcx> {
|
||
pub source_info: SourceInfo,
|
||
pub kind: StatementKind<'tcx>,
|
||
}
|
||
|
||
// `Statement` is used a lot. Make sure it doesn't unintentionally get bigger.
|
||
#[cfg(target_arch = "x86_64")]
|
||
static_assert_size!(Statement<'_>, 56);
|
||
|
||
impl<'tcx> Statement<'tcx> {
|
||
/// Changes a statement to a nop. This is both faster than deleting instructions and avoids
|
||
/// invalidating statement indices in `Location`s.
|
||
pub fn make_nop(&mut self) {
|
||
self.kind = StatementKind::Nop
|
||
}
|
||
|
||
/// Changes a statement to a nop and returns the original statement.
|
||
pub fn replace_nop(&mut self) -> Self {
|
||
Statement {
|
||
source_info: self.source_info,
|
||
kind: mem::replace(&mut self.kind, StatementKind::Nop),
|
||
}
|
||
}
|
||
}
|
||
|
||
#[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub enum StatementKind<'tcx> {
|
||
/// Write the RHS Rvalue to the LHS Place.
|
||
Assign(Place<'tcx>, Box<Rvalue<'tcx>>),
|
||
|
||
/// This represents all the reading that a pattern match may do
|
||
/// (e.g., inspecting constants and discriminant values), and the
|
||
/// kind of pattern it comes from. This is in order to adapt potential
|
||
/// error messages to these specific patterns.
|
||
///
|
||
/// Note that this also is emitted for regular `let` bindings to ensure that locals that are
|
||
/// never accessed still get some sanity checks for, e.g., `let x: ! = ..;`
|
||
FakeRead(FakeReadCause, Place<'tcx>),
|
||
|
||
/// Write the discriminant for a variant to the enum Place.
|
||
SetDiscriminant {
|
||
place: Place<'tcx>,
|
||
variant_index: VariantIdx,
|
||
},
|
||
|
||
/// Start a live range for the storage of the local.
|
||
StorageLive(Local),
|
||
|
||
/// End the current live range for the storage of the local.
|
||
StorageDead(Local),
|
||
|
||
/// Executes a piece of inline Assembly. Stored in a Box to keep the size
|
||
/// of `StatementKind` low.
|
||
InlineAsm(Box<InlineAsm<'tcx>>),
|
||
|
||
/// Retag references in the given place, ensuring they got fresh tags. This is
|
||
/// part of the Stacked Borrows model. These statements are currently only interpreted
|
||
/// by miri and only generated when "-Z mir-emit-retag" is passed.
|
||
/// See <https://internals.rust-lang.org/t/stacked-borrows-an-aliasing-model-for-rust/8153/>
|
||
/// for more details.
|
||
Retag(RetagKind, Place<'tcx>),
|
||
|
||
/// Encodes a user's type ascription. These need to be preserved
|
||
/// intact so that NLL can respect them. For example:
|
||
///
|
||
/// let a: T = y;
|
||
///
|
||
/// The effect of this annotation is to relate the type `T_y` of the place `y`
|
||
/// to the user-given type `T`. The effect depends on the specified variance:
|
||
///
|
||
/// - `Covariant` -- requires that `T_y <: T`
|
||
/// - `Contravariant` -- requires that `T_y :> T`
|
||
/// - `Invariant` -- requires that `T_y == T`
|
||
/// - `Bivariant` -- no effect
|
||
AscribeUserType(Place<'tcx>, ty::Variance, Box<UserTypeProjection>),
|
||
|
||
/// No-op. Useful for deleting instructions without affecting statement indices.
|
||
Nop,
|
||
}
|
||
|
||
/// `RetagKind` describes what kind of retag is to be performed.
|
||
#[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, PartialEq, Eq, HashStable)]
|
||
pub enum RetagKind {
|
||
/// The initial retag when entering a function
|
||
FnEntry,
|
||
/// Retag preparing for a two-phase borrow
|
||
TwoPhase,
|
||
/// Retagging raw pointers
|
||
Raw,
|
||
/// A "normal" retag
|
||
Default,
|
||
}
|
||
|
||
/// The `FakeReadCause` describes the type of pattern why a `FakeRead` statement exists.
|
||
#[derive(Copy, Clone, RustcEncodable, RustcDecodable, Debug, HashStable)]
|
||
pub enum FakeReadCause {
|
||
/// Inject a fake read of the borrowed input at the end of each guards
|
||
/// code.
|
||
///
|
||
/// This should ensure that you cannot change the variant for an enum while
|
||
/// you are in the midst of matching on it.
|
||
ForMatchGuard,
|
||
|
||
/// `let x: !; match x {}` doesn't generate any read of x so we need to
|
||
/// generate a read of x to check that it is initialized and safe.
|
||
ForMatchedPlace,
|
||
|
||
/// A fake read of the RefWithinGuard version of a bind-by-value variable
|
||
/// in a match guard to ensure that it's value hasn't change by the time
|
||
/// we create the OutsideGuard version.
|
||
ForGuardBinding,
|
||
|
||
/// Officially, the semantics of
|
||
///
|
||
/// `let pattern = <expr>;`
|
||
///
|
||
/// is that `<expr>` is evaluated into a temporary and then this temporary is
|
||
/// into the pattern.
|
||
///
|
||
/// However, if we see the simple pattern `let var = <expr>`, we optimize this to
|
||
/// evaluate `<expr>` directly into the variable `var`. This is mostly unobservable,
|
||
/// but in some cases it can affect the borrow checker, as in #53695.
|
||
/// Therefore, we insert a "fake read" here to ensure that we get
|
||
/// appropriate errors.
|
||
ForLet,
|
||
}
|
||
|
||
#[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub struct InlineAsm<'tcx> {
|
||
pub asm: HirInlineAsm,
|
||
pub outputs: Box<[Place<'tcx>]>,
|
||
pub inputs: Box<[(Span, Operand<'tcx>)]>,
|
||
}
|
||
|
||
impl<'tcx> Debug for Statement<'tcx> {
|
||
fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
|
||
use self::StatementKind::*;
|
||
match self.kind {
|
||
Assign(ref place, ref rv) => write!(fmt, "{:?} = {:?}", place, rv),
|
||
FakeRead(ref cause, ref place) => write!(fmt, "FakeRead({:?}, {:?})", cause, place),
|
||
Retag(ref kind, ref place) =>
|
||
write!(fmt, "Retag({}{:?})",
|
||
match kind {
|
||
RetagKind::FnEntry => "[fn entry] ",
|
||
RetagKind::TwoPhase => "[2phase] ",
|
||
RetagKind::Raw => "[raw] ",
|
||
RetagKind::Default => "",
|
||
},
|
||
place,
|
||
),
|
||
StorageLive(ref place) => write!(fmt, "StorageLive({:?})", place),
|
||
StorageDead(ref place) => write!(fmt, "StorageDead({:?})", place),
|
||
SetDiscriminant {
|
||
ref place,
|
||
variant_index,
|
||
} => write!(fmt, "discriminant({:?}) = {:?}", place, variant_index),
|
||
InlineAsm(ref asm) =>
|
||
write!(fmt, "asm!({:?} : {:?} : {:?})", asm.asm, asm.outputs, asm.inputs),
|
||
AscribeUserType(ref place, ref variance, ref c_ty) => {
|
||
write!(fmt, "AscribeUserType({:?}, {:?}, {:?})", place, variance, c_ty)
|
||
}
|
||
Nop => write!(fmt, "nop"),
|
||
}
|
||
}
|
||
}
|
||
|
||
///////////////////////////////////////////////////////////////////////////
|
||
// Places
|
||
|
||
/// A path to a value; something that can be evaluated without
|
||
/// changing or disturbing program state.
|
||
#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub enum Place<'tcx> {
|
||
Base(PlaceBase<'tcx>),
|
||
|
||
/// projection out of a place (access a field, deref a pointer, etc)
|
||
Projection(Box<Projection<'tcx>>),
|
||
}
|
||
|
||
#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub enum PlaceBase<'tcx> {
|
||
/// local variable
|
||
Local(Local),
|
||
|
||
/// static or static mut variable
|
||
Static(Box<Static<'tcx>>),
|
||
}
|
||
|
||
/// We store the normalized type to avoid requiring normalization when reading MIR
|
||
#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
|
||
pub struct Static<'tcx> {
|
||
pub ty: Ty<'tcx>,
|
||
pub kind: StaticKind,
|
||
}
|
||
|
||
#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, HashStable, RustcEncodable, RustcDecodable)]
|
||
pub enum StaticKind {
|
||
Promoted(Promoted),
|
||
Static(DefId),
|
||
}
|
||
|
||
impl_stable_hash_for!(struct Static<'tcx> {
|
||
ty,
|
||
kind
|
||
});
|
||
|
||
/// The `Projection` data structure defines things of the form `base.x`, `*b` or `b[index]`.
|
||
#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord,
|
||
Hash, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub struct Projection<'tcx> {
|
||
pub base: Place<'tcx>,
|
||
pub elem: PlaceElem<'tcx>,
|
||
}
|
||
|
||
#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord,
|
||
Hash, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub enum ProjectionElem<V, T> {
|
||
Deref,
|
||
Field(Field, T),
|
||
Index(V),
|
||
|
||
/// These indices are generated by slice patterns. Easiest to explain
|
||
/// by example:
|
||
///
|
||
/// ```
|
||
/// [X, _, .._, _, _] => { offset: 0, min_length: 4, from_end: false },
|
||
/// [_, X, .._, _, _] => { offset: 1, min_length: 4, from_end: false },
|
||
/// [_, _, .._, X, _] => { offset: 2, min_length: 4, from_end: true },
|
||
/// [_, _, .._, _, X] => { offset: 1, min_length: 4, from_end: true },
|
||
/// ```
|
||
ConstantIndex {
|
||
/// index or -index (in Python terms), depending on from_end
|
||
offset: u32,
|
||
/// thing being indexed must be at least this long
|
||
min_length: u32,
|
||
/// counting backwards from end?
|
||
from_end: bool,
|
||
},
|
||
|
||
/// These indices are generated by slice patterns.
|
||
///
|
||
/// slice[from:-to] in Python terms.
|
||
Subslice {
|
||
from: u32,
|
||
to: u32,
|
||
},
|
||
|
||
/// "Downcast" to a variant of an ADT. Currently, we only introduce
|
||
/// this for ADTs with more than one variant. It may be better to
|
||
/// just introduce it always, or always for enums.
|
||
///
|
||
/// The included Symbol is the name of the variant, used for printing MIR.
|
||
Downcast(Option<Symbol>, VariantIdx),
|
||
}
|
||
|
||
/// Alias for projections as they appear in places, where the base is a place
|
||
/// and the index is a local.
|
||
pub type PlaceElem<'tcx> = ProjectionElem<Local, Ty<'tcx>>;
|
||
|
||
// At least on 64 bit systems, `PlaceElem` should not be larger than two pointers.
|
||
#[cfg(target_arch = "x86_64")]
|
||
static_assert_size!(PlaceElem<'_>, 16);
|
||
|
||
/// Alias for projections as they appear in `UserTypeProjection`, where we
|
||
/// need neither the `V` parameter for `Index` nor the `T` for `Field`.
|
||
pub type ProjectionKind = ProjectionElem<(), ()>;
|
||
|
||
newtype_index! {
|
||
pub struct Field {
|
||
derive [HashStable]
|
||
DEBUG_FORMAT = "field[{}]"
|
||
}
|
||
}
|
||
|
||
impl<'tcx> Place<'tcx> {
|
||
pub const RETURN_PLACE: Place<'tcx> = Place::Base(PlaceBase::Local(RETURN_PLACE));
|
||
|
||
pub fn field(self, f: Field, ty: Ty<'tcx>) -> Place<'tcx> {
|
||
self.elem(ProjectionElem::Field(f, ty))
|
||
}
|
||
|
||
pub fn deref(self) -> Place<'tcx> {
|
||
self.elem(ProjectionElem::Deref)
|
||
}
|
||
|
||
pub fn downcast(self, adt_def: &'tcx AdtDef, variant_index: VariantIdx) -> Place<'tcx> {
|
||
self.elem(ProjectionElem::Downcast(
|
||
Some(adt_def.variants[variant_index].ident.name),
|
||
variant_index))
|
||
}
|
||
|
||
pub fn downcast_unnamed(self, variant_index: VariantIdx) -> Place<'tcx> {
|
||
self.elem(ProjectionElem::Downcast(None, variant_index))
|
||
}
|
||
|
||
pub fn index(self, index: Local) -> Place<'tcx> {
|
||
self.elem(ProjectionElem::Index(index))
|
||
}
|
||
|
||
pub fn elem(self, elem: PlaceElem<'tcx>) -> Place<'tcx> {
|
||
Place::Projection(Box::new(Projection { base: self, elem }))
|
||
}
|
||
|
||
/// Finds the innermost `Local` from this `Place`, *if* it is either a local itself or
|
||
/// a single deref of a local.
|
||
//
|
||
// FIXME: can we safely swap the semantics of `fn base_local` below in here instead?
|
||
pub fn local_or_deref_local(&self) -> Option<Local> {
|
||
match self {
|
||
Place::Base(PlaceBase::Local(local)) |
|
||
Place::Projection(box Projection {
|
||
base: Place::Base(PlaceBase::Local(local)),
|
||
elem: ProjectionElem::Deref,
|
||
}) => Some(*local),
|
||
_ => None,
|
||
}
|
||
}
|
||
|
||
/// Finds the innermost `Local` from this `Place`.
|
||
pub fn base_local(&self) -> Option<Local> {
|
||
let mut place = self;
|
||
loop {
|
||
match place {
|
||
Place::Projection(proj) => place = &proj.base,
|
||
Place::Base(PlaceBase::Static(_)) => return None,
|
||
Place::Base(PlaceBase::Local(local)) => return Some(*local),
|
||
}
|
||
}
|
||
}
|
||
|
||
/// Recursively "iterates" over place components, generating a `PlaceBase` and
|
||
/// `Projections` list and invoking `op` with a `ProjectionsIter`.
|
||
pub fn iterate<R>(
|
||
&self,
|
||
op: impl FnOnce(&PlaceBase<'tcx>, ProjectionsIter<'_, 'tcx>) -> R,
|
||
) -> R {
|
||
self.iterate2(&Projections::Empty, op)
|
||
}
|
||
|
||
fn iterate2<R>(
|
||
&self,
|
||
next: &Projections<'_, 'tcx>,
|
||
op: impl FnOnce(&PlaceBase<'tcx>, ProjectionsIter<'_, 'tcx>) -> R,
|
||
) -> R {
|
||
match self {
|
||
Place::Projection(interior) => interior.base.iterate2(
|
||
&Projections::List {
|
||
projection: interior,
|
||
next,
|
||
},
|
||
op,
|
||
),
|
||
|
||
Place::Base(base) => op(base, next.iter()),
|
||
}
|
||
}
|
||
}
|
||
|
||
/// A linked list of projections running up the stack; begins with the
|
||
/// innermost projection and extends to the outermost (e.g., `a.b.c`
|
||
/// would have the place `b` with a "next" pointer to `b.c`).
|
||
/// Created by `Place::iterate`.
|
||
///
|
||
/// N.B., this particular impl strategy is not the most obvious. It was
|
||
/// chosen because it makes a measurable difference to NLL
|
||
/// performance, as this code (`borrow_conflicts_with_place`) is somewhat hot.
|
||
pub enum Projections<'p, 'tcx: 'p> {
|
||
Empty,
|
||
|
||
List {
|
||
projection: &'p Projection<'tcx>,
|
||
next: &'p Projections<'p, 'tcx>,
|
||
}
|
||
}
|
||
|
||
impl<'p, 'tcx> Projections<'p, 'tcx> {
|
||
fn iter(&self) -> ProjectionsIter<'_, 'tcx> {
|
||
ProjectionsIter { value: self }
|
||
}
|
||
}
|
||
|
||
impl<'p, 'tcx> IntoIterator for &'p Projections<'p, 'tcx> {
|
||
type Item = &'p Projection<'tcx>;
|
||
type IntoIter = ProjectionsIter<'p, 'tcx>;
|
||
|
||
/// Converts a list of `Projection` components into an iterator;
|
||
/// this iterator yields up a never-ending stream of `Option<&Place>`.
|
||
/// These begin with the "innermost" projection and then with each
|
||
/// projection therefrom. So given a place like `a.b.c` it would
|
||
/// yield up:
|
||
///
|
||
/// ```notrust
|
||
/// Some(`a`), Some(`a.b`), Some(`a.b.c`), None, None, ...
|
||
/// ```
|
||
fn into_iter(self) -> Self::IntoIter {
|
||
self.iter()
|
||
}
|
||
}
|
||
|
||
/// Iterator over components; see `Projections::iter` for more
|
||
/// information.
|
||
///
|
||
/// N.B., this is not a *true* Rust iterator -- the code above just
|
||
/// manually invokes `next`. This is because we (sometimes) want to
|
||
/// keep executing even after `None` has been returned.
|
||
pub struct ProjectionsIter<'p, 'tcx: 'p> {
|
||
pub value: &'p Projections<'p, 'tcx>,
|
||
}
|
||
|
||
impl<'p, 'tcx> Iterator for ProjectionsIter<'p, 'tcx> {
|
||
type Item = &'p Projection<'tcx>;
|
||
|
||
fn next(&mut self) -> Option<Self::Item> {
|
||
if let &Projections::List { projection, next } = self.value {
|
||
self.value = next;
|
||
Some(projection)
|
||
} else {
|
||
None
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<'p, 'tcx> FusedIterator for ProjectionsIter<'p, 'tcx> {}
|
||
|
||
impl<'tcx> Debug for Place<'tcx> {
|
||
fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
|
||
self.iterate(|_place_base, place_projections| {
|
||
// FIXME: remove this collect once we have migrated to slices
|
||
let projs_vec: Vec<_> = place_projections.collect();
|
||
for projection in projs_vec.iter().rev() {
|
||
match projection.elem {
|
||
ProjectionElem::Downcast(_, _) |
|
||
ProjectionElem::Field(_, _) => {
|
||
write!(fmt, "(").unwrap();
|
||
}
|
||
ProjectionElem::Deref => {
|
||
write!(fmt, "(*").unwrap();
|
||
}
|
||
ProjectionElem::Index(_) |
|
||
ProjectionElem::ConstantIndex { .. } |
|
||
ProjectionElem::Subslice { .. } => {}
|
||
}
|
||
}
|
||
});
|
||
|
||
self.iterate(|place_base, place_projections| {
|
||
match place_base {
|
||
PlaceBase::Local(id) => {
|
||
write!(fmt, "{:?}", id)?;
|
||
}
|
||
PlaceBase::Static(box self::Static { ty, kind: StaticKind::Static(def_id) }) => {
|
||
write!(
|
||
fmt,
|
||
"({}: {:?})",
|
||
ty::tls::with(|tcx| tcx.def_path_str(*def_id)),
|
||
ty
|
||
)?;
|
||
},
|
||
PlaceBase::Static(
|
||
box self::Static { ty, kind: StaticKind::Promoted(promoted) }
|
||
) => {
|
||
write!(
|
||
fmt,
|
||
"({:?}: {:?})",
|
||
promoted,
|
||
ty
|
||
)?;
|
||
},
|
||
}
|
||
|
||
for projection in place_projections {
|
||
match projection.elem {
|
||
ProjectionElem::Downcast(Some(name), _index) => {
|
||
write!(fmt, " as {})", name)?;
|
||
}
|
||
ProjectionElem::Downcast(None, index) => {
|
||
write!(fmt, " as variant#{:?})", index)?;
|
||
}
|
||
ProjectionElem::Deref => {
|
||
write!(fmt, ")")?;
|
||
}
|
||
ProjectionElem::Field(field, ty) => {
|
||
write!(fmt, ".{:?}: {:?})", field.index(), ty)?;
|
||
}
|
||
ProjectionElem::Index(ref index) => {
|
||
write!(fmt, "[{:?}]", index)?;
|
||
}
|
||
ProjectionElem::ConstantIndex {
|
||
offset,
|
||
min_length,
|
||
from_end: false,
|
||
} => {
|
||
write!(fmt, "[{:?} of {:?}]", offset, min_length)?;
|
||
}
|
||
ProjectionElem::ConstantIndex {
|
||
offset,
|
||
min_length,
|
||
from_end: true,
|
||
} => {
|
||
write!(fmt, "[-{:?} of {:?}]", offset, min_length)?;
|
||
}
|
||
ProjectionElem::Subslice { from, to } if to == 0 => {
|
||
write!(fmt, "[{:?}:]", from)?;
|
||
}
|
||
ProjectionElem::Subslice { from, to } if from == 0 => {
|
||
write!(fmt, "[:-{:?}]", to)?;
|
||
}
|
||
ProjectionElem::Subslice { from, to } => {
|
||
write!(fmt, "[{:?}:-{:?}]", from, to)?;
|
||
}
|
||
}
|
||
}
|
||
|
||
Ok(())
|
||
})
|
||
}
|
||
}
|
||
|
||
///////////////////////////////////////////////////////////////////////////
|
||
// Scopes
|
||
|
||
newtype_index! {
|
||
pub struct SourceScope {
|
||
derive [HashStable]
|
||
DEBUG_FORMAT = "scope[{}]",
|
||
const OUTERMOST_SOURCE_SCOPE = 0,
|
||
}
|
||
}
|
||
|
||
#[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub struct SourceScopeData {
|
||
pub span: Span,
|
||
pub parent_scope: Option<SourceScope>,
|
||
}
|
||
|
||
#[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub struct SourceScopeLocalData {
|
||
/// A HirId with lint levels equivalent to this scope's lint levels.
|
||
pub lint_root: hir::HirId,
|
||
/// The unsafe block that contains this node.
|
||
pub safety: Safety,
|
||
}
|
||
|
||
///////////////////////////////////////////////////////////////////////////
|
||
// Operands
|
||
|
||
/// These are values that can appear inside an rvalue. They are intentionally
|
||
/// limited to prevent rvalues from being nested in one another.
|
||
#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub enum Operand<'tcx> {
|
||
/// Copy: The value must be available for use afterwards.
|
||
///
|
||
/// This implies that the type of the place must be `Copy`; this is true
|
||
/// by construction during build, but also checked by the MIR type checker.
|
||
Copy(Place<'tcx>),
|
||
|
||
/// Move: The value (including old borrows of it) will not be used again.
|
||
///
|
||
/// Safe for values of all types (modulo future developments towards `?Move`).
|
||
/// Correct usage patterns are enforced by the borrow checker for safe code.
|
||
/// `Copy` may be converted to `Move` to enable "last-use" optimizations.
|
||
Move(Place<'tcx>),
|
||
|
||
/// Synthesizes a constant value.
|
||
Constant(Box<Constant<'tcx>>),
|
||
}
|
||
|
||
impl<'tcx> Debug for Operand<'tcx> {
|
||
fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
|
||
use self::Operand::*;
|
||
match *self {
|
||
Constant(ref a) => write!(fmt, "{:?}", a),
|
||
Copy(ref place) => write!(fmt, "{:?}", place),
|
||
Move(ref place) => write!(fmt, "move {:?}", place),
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<'tcx> Operand<'tcx> {
|
||
/// Convenience helper to make a constant that refers to the fn
|
||
/// with given `DefId` and substs. Since this is used to synthesize
|
||
/// MIR, assumes `user_ty` is None.
|
||
pub fn function_handle<'a>(
|
||
tcx: TyCtxt<'a, 'tcx, 'tcx>,
|
||
def_id: DefId,
|
||
substs: SubstsRef<'tcx>,
|
||
span: Span,
|
||
) -> Self {
|
||
let ty = tcx.type_of(def_id).subst(tcx, substs);
|
||
Operand::Constant(box Constant {
|
||
span,
|
||
ty,
|
||
user_ty: None,
|
||
literal: ty::Const::zero_sized(tcx, ty),
|
||
})
|
||
}
|
||
|
||
pub fn to_copy(&self) -> Self {
|
||
match *self {
|
||
Operand::Copy(_) | Operand::Constant(_) => self.clone(),
|
||
Operand::Move(ref place) => Operand::Copy(place.clone()),
|
||
}
|
||
}
|
||
}
|
||
|
||
///////////////////////////////////////////////////////////////////////////
|
||
/// Rvalues
|
||
|
||
#[derive(Clone, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub enum Rvalue<'tcx> {
|
||
/// x (either a move or copy, depending on type of x)
|
||
Use(Operand<'tcx>),
|
||
|
||
/// [x; 32]
|
||
Repeat(Operand<'tcx>, u64),
|
||
|
||
/// &x or &mut x
|
||
Ref(Region<'tcx>, BorrowKind, Place<'tcx>),
|
||
|
||
/// length of a [X] or [X;n] value
|
||
Len(Place<'tcx>),
|
||
|
||
Cast(CastKind, Operand<'tcx>, Ty<'tcx>),
|
||
|
||
BinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
|
||
CheckedBinaryOp(BinOp, Operand<'tcx>, Operand<'tcx>),
|
||
|
||
NullaryOp(NullOp, Ty<'tcx>),
|
||
UnaryOp(UnOp, Operand<'tcx>),
|
||
|
||
/// Read the discriminant of an ADT.
|
||
///
|
||
/// Undefined (i.e., no effort is made to make it defined, but there’s no reason why it cannot
|
||
/// be defined to return, say, a 0) if ADT is not an enum.
|
||
Discriminant(Place<'tcx>),
|
||
|
||
/// Creates an aggregate value, like a tuple or struct. This is
|
||
/// only needed because we want to distinguish `dest = Foo { x:
|
||
/// ..., y: ... }` from `dest.x = ...; dest.y = ...;` in the case
|
||
/// that `Foo` has a destructor. These rvalues can be optimized
|
||
/// away after type-checking and before lowering.
|
||
Aggregate(Box<AggregateKind<'tcx>>, Vec<Operand<'tcx>>),
|
||
}
|
||
|
||
|
||
#[derive(Clone, Copy, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub enum CastKind {
|
||
Misc,
|
||
Pointer(PointerCast),
|
||
}
|
||
|
||
#[derive(Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub enum AggregateKind<'tcx> {
|
||
/// The type is of the element
|
||
Array(Ty<'tcx>),
|
||
Tuple,
|
||
|
||
/// The second field is the variant index. It's equal to 0 for struct
|
||
/// and union expressions. The fourth field is
|
||
/// active field number and is present only for union expressions
|
||
/// -- e.g., for a union expression `SomeUnion { c: .. }`, the
|
||
/// active field index would identity the field `c`
|
||
Adt(
|
||
&'tcx AdtDef,
|
||
VariantIdx,
|
||
SubstsRef<'tcx>,
|
||
Option<UserTypeAnnotationIndex>,
|
||
Option<usize>,
|
||
),
|
||
|
||
Closure(DefId, ClosureSubsts<'tcx>),
|
||
Generator(DefId, GeneratorSubsts<'tcx>, hir::GeneratorMovability),
|
||
}
|
||
|
||
#[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub enum BinOp {
|
||
/// The `+` operator (addition)
|
||
Add,
|
||
/// The `-` operator (subtraction)
|
||
Sub,
|
||
/// The `*` operator (multiplication)
|
||
Mul,
|
||
/// The `/` operator (division)
|
||
Div,
|
||
/// The `%` operator (modulus)
|
||
Rem,
|
||
/// The `^` operator (bitwise xor)
|
||
BitXor,
|
||
/// The `&` operator (bitwise and)
|
||
BitAnd,
|
||
/// The `|` operator (bitwise or)
|
||
BitOr,
|
||
/// The `<<` operator (shift left)
|
||
Shl,
|
||
/// The `>>` operator (shift right)
|
||
Shr,
|
||
/// The `==` operator (equality)
|
||
Eq,
|
||
/// The `<` operator (less than)
|
||
Lt,
|
||
/// The `<=` operator (less than or equal to)
|
||
Le,
|
||
/// The `!=` operator (not equal to)
|
||
Ne,
|
||
/// The `>=` operator (greater than or equal to)
|
||
Ge,
|
||
/// The `>` operator (greater than)
|
||
Gt,
|
||
/// The `ptr.offset` operator
|
||
Offset,
|
||
}
|
||
|
||
impl BinOp {
|
||
pub fn is_checkable(self) -> bool {
|
||
use self::BinOp::*;
|
||
match self {
|
||
Add | Sub | Mul | Shl | Shr => true,
|
||
_ => false,
|
||
}
|
||
}
|
||
}
|
||
|
||
#[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub enum NullOp {
|
||
/// Returns the size of a value of that type
|
||
SizeOf,
|
||
/// Creates a new uninitialized box for a value of that type
|
||
Box,
|
||
}
|
||
|
||
#[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub enum UnOp {
|
||
/// The `!` operator for logical inversion
|
||
Not,
|
||
/// The `-` operator for negation
|
||
Neg,
|
||
}
|
||
|
||
impl<'tcx> Debug for Rvalue<'tcx> {
|
||
fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
|
||
use self::Rvalue::*;
|
||
|
||
match *self {
|
||
Use(ref place) => write!(fmt, "{:?}", place),
|
||
Repeat(ref a, ref b) => write!(fmt, "[{:?}; {:?}]", a, b),
|
||
Len(ref a) => write!(fmt, "Len({:?})", a),
|
||
Cast(ref kind, ref place, ref ty) => {
|
||
write!(fmt, "{:?} as {:?} ({:?})", place, ty, kind)
|
||
}
|
||
BinaryOp(ref op, ref a, ref b) => write!(fmt, "{:?}({:?}, {:?})", op, a, b),
|
||
CheckedBinaryOp(ref op, ref a, ref b) => {
|
||
write!(fmt, "Checked{:?}({:?}, {:?})", op, a, b)
|
||
}
|
||
UnaryOp(ref op, ref a) => write!(fmt, "{:?}({:?})", op, a),
|
||
Discriminant(ref place) => write!(fmt, "discriminant({:?})", place),
|
||
NullaryOp(ref op, ref t) => write!(fmt, "{:?}({:?})", op, t),
|
||
Ref(region, borrow_kind, ref place) => {
|
||
let kind_str = match borrow_kind {
|
||
BorrowKind::Shared => "",
|
||
BorrowKind::Shallow => "shallow ",
|
||
BorrowKind::Mut { .. } | BorrowKind::Unique => "mut ",
|
||
};
|
||
|
||
// When printing regions, add trailing space if necessary.
|
||
let print_region = ty::tls::with(|tcx| {
|
||
tcx.sess.verbose() || tcx.sess.opts.debugging_opts.identify_regions
|
||
});
|
||
let region = if print_region {
|
||
let mut region = region.to_string();
|
||
if region.len() > 0 {
|
||
region.push(' ');
|
||
}
|
||
region
|
||
} else {
|
||
// Do not even print 'static
|
||
String::new()
|
||
};
|
||
write!(fmt, "&{}{}{:?}", region, kind_str, place)
|
||
}
|
||
|
||
Aggregate(ref kind, ref places) => {
|
||
fn fmt_tuple(fmt: &mut Formatter<'_>, places: &[Operand<'_>]) -> fmt::Result {
|
||
let mut tuple_fmt = fmt.debug_tuple("");
|
||
for place in places {
|
||
tuple_fmt.field(place);
|
||
}
|
||
tuple_fmt.finish()
|
||
}
|
||
|
||
match **kind {
|
||
AggregateKind::Array(_) => write!(fmt, "{:?}", places),
|
||
|
||
AggregateKind::Tuple => match places.len() {
|
||
0 => write!(fmt, "()"),
|
||
1 => write!(fmt, "({:?},)", places[0]),
|
||
_ => fmt_tuple(fmt, places),
|
||
},
|
||
|
||
AggregateKind::Adt(adt_def, variant, substs, _user_ty, _) => {
|
||
let variant_def = &adt_def.variants[variant];
|
||
|
||
let f = &mut *fmt;
|
||
ty::tls::with(|tcx| {
|
||
let substs = tcx.lift(&substs).expect("could not lift for printing");
|
||
FmtPrinter::new(tcx, f, Namespace::ValueNS)
|
||
.print_def_path(variant_def.def_id, substs)?;
|
||
Ok(())
|
||
})?;
|
||
|
||
match variant_def.ctor_kind {
|
||
CtorKind::Const => Ok(()),
|
||
CtorKind::Fn => fmt_tuple(fmt, places),
|
||
CtorKind::Fictive => {
|
||
let mut struct_fmt = fmt.debug_struct("");
|
||
for (field, place) in variant_def.fields.iter().zip(places) {
|
||
struct_fmt.field(&field.ident.as_str(), place);
|
||
}
|
||
struct_fmt.finish()
|
||
}
|
||
}
|
||
}
|
||
|
||
AggregateKind::Closure(def_id, _) => ty::tls::with(|tcx| {
|
||
if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
|
||
let name = if tcx.sess.opts.debugging_opts.span_free_formats {
|
||
format!("[closure@{:?}]", hir_id)
|
||
} else {
|
||
format!("[closure@{:?}]", tcx.hir().span_by_hir_id(hir_id))
|
||
};
|
||
let mut struct_fmt = fmt.debug_struct(&name);
|
||
|
||
if let Some(upvars) = tcx.upvars(def_id) {
|
||
for (&var_id, place) in upvars.keys().zip(places) {
|
||
let var_name = tcx.hir().name_by_hir_id(var_id);
|
||
struct_fmt.field(&var_name.as_str(), place);
|
||
}
|
||
}
|
||
|
||
struct_fmt.finish()
|
||
} else {
|
||
write!(fmt, "[closure]")
|
||
}
|
||
}),
|
||
|
||
AggregateKind::Generator(def_id, _, _) => ty::tls::with(|tcx| {
|
||
if let Some(hir_id) = tcx.hir().as_local_hir_id(def_id) {
|
||
let name = format!("[generator@{:?}]",
|
||
tcx.hir().span_by_hir_id(hir_id));
|
||
let mut struct_fmt = fmt.debug_struct(&name);
|
||
|
||
if let Some(upvars) = tcx.upvars(def_id) {
|
||
for (&var_id, place) in upvars.keys().zip(places) {
|
||
let var_name = tcx.hir().name_by_hir_id(var_id);
|
||
struct_fmt.field(&var_name.as_str(), place);
|
||
}
|
||
}
|
||
|
||
struct_fmt.finish()
|
||
} else {
|
||
write!(fmt, "[generator]")
|
||
}
|
||
}),
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
///////////////////////////////////////////////////////////////////////////
|
||
/// Constants
|
||
///
|
||
/// Two constants are equal if they are the same constant. Note that
|
||
/// this does not necessarily mean that they are "==" in Rust -- in
|
||
/// particular one must be wary of `NaN`!
|
||
|
||
#[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub struct Constant<'tcx> {
|
||
pub span: Span,
|
||
pub ty: Ty<'tcx>,
|
||
|
||
/// Optional user-given type: for something like
|
||
/// `collect::<Vec<_>>`, this would be present and would
|
||
/// indicate that `Vec<_>` was explicitly specified.
|
||
///
|
||
/// Needed for NLL to impose user-given type constraints.
|
||
pub user_ty: Option<UserTypeAnnotationIndex>,
|
||
|
||
pub literal: &'tcx ty::Const<'tcx>,
|
||
}
|
||
|
||
/// A collection of projections into user types.
|
||
///
|
||
/// They are projections because a binding can occur a part of a
|
||
/// parent pattern that has been ascribed a type.
|
||
///
|
||
/// Its a collection because there can be multiple type ascriptions on
|
||
/// the path from the root of the pattern down to the binding itself.
|
||
///
|
||
/// An example:
|
||
///
|
||
/// ```rust
|
||
/// struct S<'a>((i32, &'a str), String);
|
||
/// let S((_, w): (i32, &'static str), _): S = ...;
|
||
/// // ------ ^^^^^^^^^^^^^^^^^^^ (1)
|
||
/// // --------------------------------- ^ (2)
|
||
/// ```
|
||
///
|
||
/// The highlights labelled `(1)` show the subpattern `(_, w)` being
|
||
/// ascribed the type `(i32, &'static str)`.
|
||
///
|
||
/// The highlights labelled `(2)` show the whole pattern being
|
||
/// ascribed the type `S`.
|
||
///
|
||
/// In this example, when we descend to `w`, we will have built up the
|
||
/// following two projected types:
|
||
///
|
||
/// * base: `S`, projection: `(base.0).1`
|
||
/// * base: `(i32, &'static str)`, projection: `base.1`
|
||
///
|
||
/// The first will lead to the constraint `w: &'1 str` (for some
|
||
/// inferred region `'1`). The second will lead to the constraint `w:
|
||
/// &'static str`.
|
||
#[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub struct UserTypeProjections {
|
||
pub(crate) contents: Vec<(UserTypeProjection, Span)>,
|
||
}
|
||
|
||
BraceStructTypeFoldableImpl! {
|
||
impl<'tcx> TypeFoldable<'tcx> for UserTypeProjections {
|
||
contents
|
||
}
|
||
}
|
||
|
||
impl<'tcx> UserTypeProjections {
|
||
pub fn none() -> Self {
|
||
UserTypeProjections { contents: vec![] }
|
||
}
|
||
|
||
pub fn from_projections(projs: impl Iterator<Item=(UserTypeProjection, Span)>) -> Self {
|
||
UserTypeProjections { contents: projs.collect() }
|
||
}
|
||
|
||
pub fn projections_and_spans(&self) -> impl Iterator<Item=&(UserTypeProjection, Span)> {
|
||
self.contents.iter()
|
||
}
|
||
|
||
pub fn projections(&self) -> impl Iterator<Item=&UserTypeProjection> {
|
||
self.contents.iter().map(|&(ref user_type, _span)| user_type)
|
||
}
|
||
|
||
pub fn push_projection(
|
||
mut self,
|
||
user_ty: &UserTypeProjection,
|
||
span: Span,
|
||
) -> Self {
|
||
self.contents.push((user_ty.clone(), span));
|
||
self
|
||
}
|
||
|
||
fn map_projections(
|
||
mut self,
|
||
mut f: impl FnMut(UserTypeProjection) -> UserTypeProjection
|
||
) -> Self {
|
||
self.contents = self.contents.drain(..).map(|(proj, span)| (f(proj), span)).collect();
|
||
self
|
||
}
|
||
|
||
pub fn index(self) -> Self {
|
||
self.map_projections(|pat_ty_proj| pat_ty_proj.index())
|
||
}
|
||
|
||
pub fn subslice(self, from: u32, to: u32) -> Self {
|
||
self.map_projections(|pat_ty_proj| pat_ty_proj.subslice(from, to))
|
||
}
|
||
|
||
pub fn deref(self) -> Self {
|
||
self.map_projections(|pat_ty_proj| pat_ty_proj.deref())
|
||
}
|
||
|
||
pub fn leaf(self, field: Field) -> Self {
|
||
self.map_projections(|pat_ty_proj| pat_ty_proj.leaf(field))
|
||
}
|
||
|
||
pub fn variant(
|
||
self,
|
||
adt_def: &'tcx AdtDef,
|
||
variant_index: VariantIdx,
|
||
field: Field,
|
||
) -> Self {
|
||
self.map_projections(|pat_ty_proj| pat_ty_proj.variant(adt_def, variant_index, field))
|
||
}
|
||
}
|
||
|
||
/// Encodes the effect of a user-supplied type annotation on the
|
||
/// subcomponents of a pattern. The effect is determined by applying the
|
||
/// given list of proejctions to some underlying base type. Often,
|
||
/// the projection element list `projs` is empty, in which case this
|
||
/// directly encodes a type in `base`. But in the case of complex patterns with
|
||
/// subpatterns and bindings, we want to apply only a *part* of the type to a variable,
|
||
/// in which case the `projs` vector is used.
|
||
///
|
||
/// Examples:
|
||
///
|
||
/// * `let x: T = ...` -- here, the `projs` vector is empty.
|
||
///
|
||
/// * `let (x, _): T = ...` -- here, the `projs` vector would contain
|
||
/// `field[0]` (aka `.0`), indicating that the type of `s` is
|
||
/// determined by finding the type of the `.0` field from `T`.
|
||
#[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub struct UserTypeProjection {
|
||
pub base: UserTypeAnnotationIndex,
|
||
pub projs: Vec<ProjectionKind>,
|
||
}
|
||
|
||
impl Copy for ProjectionKind { }
|
||
|
||
impl UserTypeProjection {
|
||
pub(crate) fn index(mut self) -> Self {
|
||
self.projs.push(ProjectionElem::Index(()));
|
||
self
|
||
}
|
||
|
||
pub(crate) fn subslice(mut self, from: u32, to: u32) -> Self {
|
||
self.projs.push(ProjectionElem::Subslice { from, to });
|
||
self
|
||
}
|
||
|
||
pub(crate) fn deref(mut self) -> Self {
|
||
self.projs.push(ProjectionElem::Deref);
|
||
self
|
||
}
|
||
|
||
pub(crate) fn leaf(mut self, field: Field) -> Self {
|
||
self.projs.push(ProjectionElem::Field(field, ()));
|
||
self
|
||
}
|
||
|
||
pub(crate) fn variant(
|
||
mut self,
|
||
adt_def: &'tcx AdtDef,
|
||
variant_index: VariantIdx,
|
||
field: Field,
|
||
) -> Self {
|
||
self.projs.push(ProjectionElem::Downcast(
|
||
Some(adt_def.variants[variant_index].ident.name),
|
||
variant_index));
|
||
self.projs.push(ProjectionElem::Field(field, ()));
|
||
self
|
||
}
|
||
}
|
||
|
||
CloneTypeFoldableAndLiftImpls! { ProjectionKind, }
|
||
|
||
impl<'tcx> TypeFoldable<'tcx> for UserTypeProjection {
|
||
fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
|
||
use crate::mir::ProjectionElem::*;
|
||
|
||
let base = self.base.fold_with(folder);
|
||
let projs: Vec<_> = self.projs
|
||
.iter()
|
||
.map(|elem| {
|
||
match elem {
|
||
Deref => Deref,
|
||
Field(f, ()) => Field(f.clone(), ()),
|
||
Index(()) => Index(()),
|
||
elem => elem.clone(),
|
||
}})
|
||
.collect();
|
||
|
||
UserTypeProjection { base, projs }
|
||
}
|
||
|
||
fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
|
||
self.base.visit_with(visitor)
|
||
// Note: there's nothing in `self.proj` to visit.
|
||
}
|
||
}
|
||
|
||
newtype_index! {
|
||
pub struct Promoted {
|
||
derive [HashStable]
|
||
DEBUG_FORMAT = "promoted[{}]"
|
||
}
|
||
}
|
||
|
||
impl<'tcx> Debug for Constant<'tcx> {
|
||
fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
|
||
write!(fmt, "{}", self)
|
||
}
|
||
}
|
||
|
||
impl<'tcx> Display for Constant<'tcx> {
|
||
fn fmt(&self, fmt: &mut Formatter<'_>) -> fmt::Result {
|
||
write!(fmt, "const ")?;
|
||
write!(fmt, "{}", self.literal)
|
||
}
|
||
}
|
||
|
||
impl<'tcx> graph::DirectedGraph for Body<'tcx> {
|
||
type Node = BasicBlock;
|
||
}
|
||
|
||
impl<'tcx> graph::WithNumNodes for Body<'tcx> {
|
||
fn num_nodes(&self) -> usize {
|
||
self.basic_blocks.len()
|
||
}
|
||
}
|
||
|
||
impl<'tcx> graph::WithStartNode for Body<'tcx> {
|
||
fn start_node(&self) -> Self::Node {
|
||
START_BLOCK
|
||
}
|
||
}
|
||
|
||
impl<'tcx> graph::WithPredecessors for Body<'tcx> {
|
||
fn predecessors<'graph>(
|
||
&'graph self,
|
||
node: Self::Node,
|
||
) -> <Self as GraphPredecessors<'graph>>::Iter {
|
||
self.predecessors_for(node).clone().into_iter()
|
||
}
|
||
}
|
||
|
||
impl<'tcx> graph::WithSuccessors for Body<'tcx> {
|
||
fn successors<'graph>(
|
||
&'graph self,
|
||
node: Self::Node,
|
||
) -> <Self as GraphSuccessors<'graph>>::Iter {
|
||
self.basic_blocks[node].terminator().successors().cloned()
|
||
}
|
||
}
|
||
|
||
impl<'a, 'b> graph::GraphPredecessors<'b> for Body<'a> {
|
||
type Item = BasicBlock;
|
||
type Iter = IntoIter<BasicBlock>;
|
||
}
|
||
|
||
impl<'a, 'b> graph::GraphSuccessors<'b> for Body<'a> {
|
||
type Item = BasicBlock;
|
||
type Iter = iter::Cloned<Successors<'b>>;
|
||
}
|
||
|
||
#[derive(Copy, Clone, PartialEq, Eq, Hash, Ord, PartialOrd, HashStable)]
|
||
pub struct Location {
|
||
/// the location is within this block
|
||
pub block: BasicBlock,
|
||
|
||
/// the location is the start of the statement; or, if `statement_index`
|
||
/// == num-statements, then the start of the terminator.
|
||
pub statement_index: usize,
|
||
}
|
||
|
||
impl fmt::Debug for Location {
|
||
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
|
||
write!(fmt, "{:?}[{}]", self.block, self.statement_index)
|
||
}
|
||
}
|
||
|
||
impl Location {
|
||
pub const START: Location = Location {
|
||
block: START_BLOCK,
|
||
statement_index: 0,
|
||
};
|
||
|
||
/// Returns the location immediately after this one within the enclosing block.
|
||
///
|
||
/// Note that if this location represents a terminator, then the
|
||
/// resulting location would be out of bounds and invalid.
|
||
pub fn successor_within_block(&self) -> Location {
|
||
Location {
|
||
block: self.block,
|
||
statement_index: self.statement_index + 1,
|
||
}
|
||
}
|
||
|
||
/// Returns `true` if `other` is earlier in the control flow graph than `self`.
|
||
pub fn is_predecessor_of<'tcx>(&self, other: Location, mir: &Body<'tcx>) -> bool {
|
||
// If we are in the same block as the other location and are an earlier statement
|
||
// then we are a predecessor of `other`.
|
||
if self.block == other.block && self.statement_index < other.statement_index {
|
||
return true;
|
||
}
|
||
|
||
// If we're in another block, then we want to check that block is a predecessor of `other`.
|
||
let mut queue: Vec<BasicBlock> = mir.predecessors_for(other.block).clone();
|
||
let mut visited = FxHashSet::default();
|
||
|
||
while let Some(block) = queue.pop() {
|
||
// If we haven't visited this block before, then make sure we visit it's predecessors.
|
||
if visited.insert(block) {
|
||
queue.append(&mut mir.predecessors_for(block).clone());
|
||
} else {
|
||
continue;
|
||
}
|
||
|
||
// If we found the block that `self` is in, then we are a predecessor of `other` (since
|
||
// we found that block by looking at the predecessors of `other`).
|
||
if self.block == block {
|
||
return true;
|
||
}
|
||
}
|
||
|
||
false
|
||
}
|
||
|
||
pub fn dominates(&self, other: Location, dominators: &Dominators<BasicBlock>) -> bool {
|
||
if self.block == other.block {
|
||
self.statement_index <= other.statement_index
|
||
} else {
|
||
dominators.is_dominated_by(other.block, self.block)
|
||
}
|
||
}
|
||
}
|
||
|
||
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub enum UnsafetyViolationKind {
|
||
General,
|
||
/// Permitted in const fn and regular fns.
|
||
GeneralAndConstFn,
|
||
ExternStatic(hir::HirId),
|
||
BorrowPacked(hir::HirId),
|
||
}
|
||
|
||
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub struct UnsafetyViolation {
|
||
pub source_info: SourceInfo,
|
||
pub description: InternedString,
|
||
pub details: InternedString,
|
||
pub kind: UnsafetyViolationKind,
|
||
}
|
||
|
||
#[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub struct UnsafetyCheckResult {
|
||
/// Violations that are propagated *upwards* from this function
|
||
pub violations: Lrc<[UnsafetyViolation]>,
|
||
/// unsafe blocks in this function, along with whether they are used. This is
|
||
/// used for the "unused_unsafe" lint.
|
||
pub unsafe_blocks: Lrc<[(hir::HirId, bool)]>,
|
||
}
|
||
|
||
newtype_index! {
|
||
pub struct GeneratorSavedLocal {
|
||
derive [HashStable]
|
||
DEBUG_FORMAT = "_{}",
|
||
}
|
||
}
|
||
|
||
/// The layout of generator state
|
||
#[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub struct GeneratorLayout<'tcx> {
|
||
/// The type of every local stored inside the generator.
|
||
pub field_tys: IndexVec<GeneratorSavedLocal, Ty<'tcx>>,
|
||
|
||
/// Which of the above fields are in each variant. Note that one field may
|
||
/// be stored in multiple variants.
|
||
pub variant_fields: IndexVec<VariantIdx, IndexVec<Field, GeneratorSavedLocal>>,
|
||
|
||
/// Names and scopes of all the stored generator locals.
|
||
/// NOTE(tmandry) This is *strictly* a temporary hack for codegen
|
||
/// debuginfo generation, and will be removed at some point.
|
||
/// Do **NOT** use it for anything else, local information should not be
|
||
/// in the MIR, please rely on local crate HIR or other side-channels.
|
||
pub __local_debuginfo_codegen_only_do_not_use: IndexVec<GeneratorSavedLocal, LocalDecl<'tcx>>,
|
||
}
|
||
|
||
#[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub struct BorrowCheckResult<'gcx> {
|
||
pub closure_requirements: Option<ClosureRegionRequirements<'gcx>>,
|
||
pub used_mut_upvars: SmallVec<[Field; 8]>,
|
||
}
|
||
|
||
/// After we borrow check a closure, we are left with various
|
||
/// requirements that we have inferred between the free regions that
|
||
/// appear in the closure's signature or on its field types. These
|
||
/// requirements are then verified and proved by the closure's
|
||
/// creating function. This struct encodes those requirements.
|
||
///
|
||
/// The requirements are listed as being between various
|
||
/// `RegionVid`. The 0th region refers to `'static`; subsequent region
|
||
/// vids refer to the free regions that appear in the closure (or
|
||
/// generator's) type, in order of appearance. (This numbering is
|
||
/// actually defined by the `UniversalRegions` struct in the NLL
|
||
/// region checker. See for example
|
||
/// `UniversalRegions::closure_mapping`.) Note that we treat the free
|
||
/// regions in the closure's type "as if" they were erased, so their
|
||
/// precise identity is not important, only their position.
|
||
///
|
||
/// Example: If type check produces a closure with the closure substs:
|
||
///
|
||
/// ```text
|
||
/// ClosureSubsts = [
|
||
/// i8, // the "closure kind"
|
||
/// for<'x> fn(&'a &'x u32) -> &'x u32, // the "closure signature"
|
||
/// &'a String, // some upvar
|
||
/// ]
|
||
/// ```
|
||
///
|
||
/// here, there is one unique free region (`'a`) but it appears
|
||
/// twice. We would "renumber" each occurrence to a unique vid, as follows:
|
||
///
|
||
/// ```text
|
||
/// ClosureSubsts = [
|
||
/// i8, // the "closure kind"
|
||
/// for<'x> fn(&'1 &'x u32) -> &'x u32, // the "closure signature"
|
||
/// &'2 String, // some upvar
|
||
/// ]
|
||
/// ```
|
||
///
|
||
/// Now the code might impose a requirement like `'1: '2`. When an
|
||
/// instance of the closure is created, the corresponding free regions
|
||
/// can be extracted from its type and constrained to have the given
|
||
/// outlives relationship.
|
||
///
|
||
/// In some cases, we have to record outlives requirements between
|
||
/// types and regions as well. In that case, if those types include
|
||
/// any regions, those regions are recorded as `ReClosureBound`
|
||
/// instances assigned one of these same indices. Those regions will
|
||
/// be substituted away by the creator. We use `ReClosureBound` in
|
||
/// that case because the regions must be allocated in the global
|
||
/// TyCtxt, and hence we cannot use `ReVar` (which is what we use
|
||
/// internally within the rest of the NLL code).
|
||
#[derive(Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub struct ClosureRegionRequirements<'gcx> {
|
||
/// The number of external regions defined on the closure. In our
|
||
/// example above, it would be 3 -- one for `'static`, then `'1`
|
||
/// and `'2`. This is just used for a sanity check later on, to
|
||
/// make sure that the number of regions we see at the callsite
|
||
/// matches.
|
||
pub num_external_vids: usize,
|
||
|
||
/// Requirements between the various free regions defined in
|
||
/// indices.
|
||
pub outlives_requirements: Vec<ClosureOutlivesRequirement<'gcx>>,
|
||
}
|
||
|
||
/// Indicates an outlives constraint between a type or between two
|
||
/// free-regions declared on the closure.
|
||
#[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub struct ClosureOutlivesRequirement<'tcx> {
|
||
// This region or type ...
|
||
pub subject: ClosureOutlivesSubject<'tcx>,
|
||
|
||
// ... must outlive this one.
|
||
pub outlived_free_region: ty::RegionVid,
|
||
|
||
// If not, report an error here ...
|
||
pub blame_span: Span,
|
||
|
||
// ... due to this reason.
|
||
pub category: ConstraintCategory,
|
||
}
|
||
|
||
/// Outlives constraints can be categorized to determine whether and why they
|
||
/// are interesting (for error reporting). Order of variants indicates sort
|
||
/// order of the category, thereby influencing diagnostic output.
|
||
///
|
||
/// See also [rustc_mir::borrow_check::nll::constraints]
|
||
#[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord,
|
||
Hash, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub enum ConstraintCategory {
|
||
Return,
|
||
Yield,
|
||
UseAsConst,
|
||
UseAsStatic,
|
||
TypeAnnotation,
|
||
Cast,
|
||
|
||
/// A constraint that came from checking the body of a closure.
|
||
///
|
||
/// We try to get the category that the closure used when reporting this.
|
||
ClosureBounds,
|
||
CallArgument,
|
||
CopyBound,
|
||
SizedBound,
|
||
Assignment,
|
||
OpaqueType,
|
||
|
||
/// A "boring" constraint (caused by the given location) is one that
|
||
/// the user probably doesn't want to see described in diagnostics,
|
||
/// because it is kind of an artifact of the type system setup.
|
||
/// Example: `x = Foo { field: y }` technically creates
|
||
/// intermediate regions representing the "type of `Foo { field: y
|
||
/// }`", and data flows from `y` into those variables, but they
|
||
/// are not very interesting. The assignment into `x` on the other
|
||
/// hand might be.
|
||
Boring,
|
||
// Boring and applicable everywhere.
|
||
BoringNoLocation,
|
||
|
||
/// A constraint that doesn't correspond to anything the user sees.
|
||
Internal,
|
||
}
|
||
|
||
/// The subject of a ClosureOutlivesRequirement -- that is, the thing
|
||
/// that must outlive some region.
|
||
#[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable, HashStable)]
|
||
pub enum ClosureOutlivesSubject<'tcx> {
|
||
/// Subject is a type, typically a type parameter, but could also
|
||
/// be a projection. Indicates a requirement like `T: 'a` being
|
||
/// passed to the caller, where the type here is `T`.
|
||
///
|
||
/// The type here is guaranteed not to contain any free regions at
|
||
/// present.
|
||
Ty(Ty<'tcx>),
|
||
|
||
/// Subject is a free region from the closure. Indicates a requirement
|
||
/// like `'a: 'b` being passed to the caller; the region here is `'a`.
|
||
Region(ty::RegionVid),
|
||
}
|
||
|
||
/*
|
||
* TypeFoldable implementations for MIR types
|
||
*/
|
||
|
||
CloneTypeFoldableAndLiftImpls! {
|
||
BlockTailInfo,
|
||
MirPhase,
|
||
Mutability,
|
||
SourceInfo,
|
||
UpvarDebuginfo,
|
||
FakeReadCause,
|
||
RetagKind,
|
||
SourceScope,
|
||
SourceScopeData,
|
||
SourceScopeLocalData,
|
||
UserTypeAnnotationIndex,
|
||
}
|
||
|
||
BraceStructTypeFoldableImpl! {
|
||
impl<'tcx> TypeFoldable<'tcx> for Body<'tcx> {
|
||
phase,
|
||
basic_blocks,
|
||
source_scopes,
|
||
source_scope_local_data,
|
||
promoted,
|
||
yield_ty,
|
||
generator_drop,
|
||
generator_layout,
|
||
local_decls,
|
||
user_type_annotations,
|
||
arg_count,
|
||
__upvar_debuginfo_codegen_only_do_not_use,
|
||
spread_arg,
|
||
control_flow_destroyed,
|
||
span,
|
||
cache,
|
||
}
|
||
}
|
||
|
||
BraceStructTypeFoldableImpl! {
|
||
impl<'tcx> TypeFoldable<'tcx> for GeneratorLayout<'tcx> {
|
||
field_tys,
|
||
variant_fields,
|
||
__local_debuginfo_codegen_only_do_not_use,
|
||
}
|
||
}
|
||
|
||
BraceStructTypeFoldableImpl! {
|
||
impl<'tcx> TypeFoldable<'tcx> for LocalDecl<'tcx> {
|
||
mutability,
|
||
is_user_variable,
|
||
internal,
|
||
ty,
|
||
user_ty,
|
||
name,
|
||
source_info,
|
||
is_block_tail,
|
||
visibility_scope,
|
||
}
|
||
}
|
||
|
||
BraceStructTypeFoldableImpl! {
|
||
impl<'tcx> TypeFoldable<'tcx> for BasicBlockData<'tcx> {
|
||
statements,
|
||
terminator,
|
||
is_cleanup,
|
||
}
|
||
}
|
||
|
||
BraceStructTypeFoldableImpl! {
|
||
impl<'tcx> TypeFoldable<'tcx> for Statement<'tcx> {
|
||
source_info, kind
|
||
}
|
||
}
|
||
|
||
EnumTypeFoldableImpl! {
|
||
impl<'tcx> TypeFoldable<'tcx> for StatementKind<'tcx> {
|
||
(StatementKind::Assign)(a, b),
|
||
(StatementKind::FakeRead)(cause, place),
|
||
(StatementKind::SetDiscriminant) { place, variant_index },
|
||
(StatementKind::StorageLive)(a),
|
||
(StatementKind::StorageDead)(a),
|
||
(StatementKind::InlineAsm)(a),
|
||
(StatementKind::Retag)(kind, place),
|
||
(StatementKind::AscribeUserType)(a, v, b),
|
||
(StatementKind::Nop),
|
||
}
|
||
}
|
||
|
||
BraceStructTypeFoldableImpl! {
|
||
impl<'tcx> TypeFoldable<'tcx> for InlineAsm<'tcx> {
|
||
asm,
|
||
outputs,
|
||
inputs,
|
||
}
|
||
}
|
||
|
||
EnumTypeFoldableImpl! {
|
||
impl<'tcx, T> TypeFoldable<'tcx> for ClearCrossCrate<T> {
|
||
(ClearCrossCrate::Clear),
|
||
(ClearCrossCrate::Set)(a),
|
||
} where T: TypeFoldable<'tcx>
|
||
}
|
||
|
||
impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
|
||
fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
|
||
use crate::mir::TerminatorKind::*;
|
||
|
||
let kind = match self.kind {
|
||
Goto { target } => Goto { target },
|
||
SwitchInt {
|
||
ref discr,
|
||
switch_ty,
|
||
ref values,
|
||
ref targets,
|
||
} => SwitchInt {
|
||
discr: discr.fold_with(folder),
|
||
switch_ty: switch_ty.fold_with(folder),
|
||
values: values.clone(),
|
||
targets: targets.clone(),
|
||
},
|
||
Drop {
|
||
ref location,
|
||
target,
|
||
unwind,
|
||
} => Drop {
|
||
location: location.fold_with(folder),
|
||
target,
|
||
unwind,
|
||
},
|
||
DropAndReplace {
|
||
ref location,
|
||
ref value,
|
||
target,
|
||
unwind,
|
||
} => DropAndReplace {
|
||
location: location.fold_with(folder),
|
||
value: value.fold_with(folder),
|
||
target,
|
||
unwind,
|
||
},
|
||
Yield {
|
||
ref value,
|
||
resume,
|
||
drop,
|
||
} => Yield {
|
||
value: value.fold_with(folder),
|
||
resume: resume,
|
||
drop: drop,
|
||
},
|
||
Call {
|
||
ref func,
|
||
ref args,
|
||
ref destination,
|
||
cleanup,
|
||
from_hir_call,
|
||
} => {
|
||
let dest = destination
|
||
.as_ref()
|
||
.map(|&(ref loc, dest)| (loc.fold_with(folder), dest));
|
||
|
||
Call {
|
||
func: func.fold_with(folder),
|
||
args: args.fold_with(folder),
|
||
destination: dest,
|
||
cleanup,
|
||
from_hir_call,
|
||
}
|
||
}
|
||
Assert {
|
||
ref cond,
|
||
expected,
|
||
ref msg,
|
||
target,
|
||
cleanup,
|
||
} => {
|
||
let msg = if let InterpError::BoundsCheck { ref len, ref index } = *msg {
|
||
InterpError::BoundsCheck {
|
||
len: len.fold_with(folder),
|
||
index: index.fold_with(folder),
|
||
}
|
||
} else {
|
||
msg.clone()
|
||
};
|
||
Assert {
|
||
cond: cond.fold_with(folder),
|
||
expected,
|
||
msg,
|
||
target,
|
||
cleanup,
|
||
}
|
||
}
|
||
GeneratorDrop => GeneratorDrop,
|
||
Resume => Resume,
|
||
Abort => Abort,
|
||
Return => Return,
|
||
Unreachable => Unreachable,
|
||
FalseEdges {
|
||
real_target,
|
||
ref imaginary_targets,
|
||
} => FalseEdges {
|
||
real_target,
|
||
imaginary_targets: imaginary_targets.clone(),
|
||
},
|
||
FalseUnwind {
|
||
real_target,
|
||
unwind,
|
||
} => FalseUnwind {
|
||
real_target,
|
||
unwind,
|
||
},
|
||
};
|
||
Terminator {
|
||
source_info: self.source_info,
|
||
kind,
|
||
}
|
||
}
|
||
|
||
fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
|
||
use crate::mir::TerminatorKind::*;
|
||
|
||
match self.kind {
|
||
SwitchInt {
|
||
ref discr,
|
||
switch_ty,
|
||
..
|
||
} => discr.visit_with(visitor) || switch_ty.visit_with(visitor),
|
||
Drop { ref location, .. } => location.visit_with(visitor),
|
||
DropAndReplace {
|
||
ref location,
|
||
ref value,
|
||
..
|
||
} => location.visit_with(visitor) || value.visit_with(visitor),
|
||
Yield { ref value, .. } => value.visit_with(visitor),
|
||
Call {
|
||
ref func,
|
||
ref args,
|
||
ref destination,
|
||
..
|
||
} => {
|
||
let dest = if let Some((ref loc, _)) = *destination {
|
||
loc.visit_with(visitor)
|
||
} else {
|
||
false
|
||
};
|
||
dest || func.visit_with(visitor) || args.visit_with(visitor)
|
||
}
|
||
Assert {
|
||
ref cond, ref msg, ..
|
||
} => {
|
||
if cond.visit_with(visitor) {
|
||
if let InterpError::BoundsCheck { ref len, ref index } = *msg {
|
||
len.visit_with(visitor) || index.visit_with(visitor)
|
||
} else {
|
||
false
|
||
}
|
||
} else {
|
||
false
|
||
}
|
||
}
|
||
Goto { .. }
|
||
| Resume
|
||
| Abort
|
||
| Return
|
||
| GeneratorDrop
|
||
| Unreachable
|
||
| FalseEdges { .. }
|
||
| FalseUnwind { .. } => false,
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<'tcx> TypeFoldable<'tcx> for Place<'tcx> {
|
||
fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
|
||
match self {
|
||
&Place::Projection(ref p) => Place::Projection(p.fold_with(folder)),
|
||
_ => self.clone(),
|
||
}
|
||
}
|
||
|
||
fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
|
||
if let &Place::Projection(ref p) = self {
|
||
p.visit_with(visitor)
|
||
} else {
|
||
false
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<'tcx> TypeFoldable<'tcx> for Rvalue<'tcx> {
|
||
fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
|
||
use crate::mir::Rvalue::*;
|
||
match *self {
|
||
Use(ref op) => Use(op.fold_with(folder)),
|
||
Repeat(ref op, len) => Repeat(op.fold_with(folder), len),
|
||
Ref(region, bk, ref place) => {
|
||
Ref(region.fold_with(folder), bk, place.fold_with(folder))
|
||
}
|
||
Len(ref place) => Len(place.fold_with(folder)),
|
||
Cast(kind, ref op, ty) => Cast(kind, op.fold_with(folder), ty.fold_with(folder)),
|
||
BinaryOp(op, ref rhs, ref lhs) => {
|
||
BinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
|
||
}
|
||
CheckedBinaryOp(op, ref rhs, ref lhs) => {
|
||
CheckedBinaryOp(op, rhs.fold_with(folder), lhs.fold_with(folder))
|
||
}
|
||
UnaryOp(op, ref val) => UnaryOp(op, val.fold_with(folder)),
|
||
Discriminant(ref place) => Discriminant(place.fold_with(folder)),
|
||
NullaryOp(op, ty) => NullaryOp(op, ty.fold_with(folder)),
|
||
Aggregate(ref kind, ref fields) => {
|
||
let kind = box match **kind {
|
||
AggregateKind::Array(ty) => AggregateKind::Array(ty.fold_with(folder)),
|
||
AggregateKind::Tuple => AggregateKind::Tuple,
|
||
AggregateKind::Adt(def, v, substs, user_ty, n) => AggregateKind::Adt(
|
||
def,
|
||
v,
|
||
substs.fold_with(folder),
|
||
user_ty.fold_with(folder),
|
||
n,
|
||
),
|
||
AggregateKind::Closure(id, substs) => {
|
||
AggregateKind::Closure(id, substs.fold_with(folder))
|
||
}
|
||
AggregateKind::Generator(id, substs, movablity) => {
|
||
AggregateKind::Generator(id, substs.fold_with(folder), movablity)
|
||
}
|
||
};
|
||
Aggregate(kind, fields.fold_with(folder))
|
||
}
|
||
}
|
||
}
|
||
|
||
fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
|
||
use crate::mir::Rvalue::*;
|
||
match *self {
|
||
Use(ref op) => op.visit_with(visitor),
|
||
Repeat(ref op, _) => op.visit_with(visitor),
|
||
Ref(region, _, ref place) => region.visit_with(visitor) || place.visit_with(visitor),
|
||
Len(ref place) => place.visit_with(visitor),
|
||
Cast(_, ref op, ty) => op.visit_with(visitor) || ty.visit_with(visitor),
|
||
BinaryOp(_, ref rhs, ref lhs) | CheckedBinaryOp(_, ref rhs, ref lhs) => {
|
||
rhs.visit_with(visitor) || lhs.visit_with(visitor)
|
||
}
|
||
UnaryOp(_, ref val) => val.visit_with(visitor),
|
||
Discriminant(ref place) => place.visit_with(visitor),
|
||
NullaryOp(_, ty) => ty.visit_with(visitor),
|
||
Aggregate(ref kind, ref fields) => {
|
||
(match **kind {
|
||
AggregateKind::Array(ty) => ty.visit_with(visitor),
|
||
AggregateKind::Tuple => false,
|
||
AggregateKind::Adt(_, _, substs, user_ty, _) => {
|
||
substs.visit_with(visitor) || user_ty.visit_with(visitor)
|
||
}
|
||
AggregateKind::Closure(_, substs) => substs.visit_with(visitor),
|
||
AggregateKind::Generator(_, substs, _) => substs.visit_with(visitor),
|
||
}) || fields.visit_with(visitor)
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<'tcx> TypeFoldable<'tcx> for Operand<'tcx> {
|
||
fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
|
||
match *self {
|
||
Operand::Copy(ref place) => Operand::Copy(place.fold_with(folder)),
|
||
Operand::Move(ref place) => Operand::Move(place.fold_with(folder)),
|
||
Operand::Constant(ref c) => Operand::Constant(c.fold_with(folder)),
|
||
}
|
||
}
|
||
|
||
fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
|
||
match *self {
|
||
Operand::Copy(ref place) | Operand::Move(ref place) => place.visit_with(visitor),
|
||
Operand::Constant(ref c) => c.visit_with(visitor),
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<'tcx> TypeFoldable<'tcx> for Projection<'tcx> {
|
||
fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
|
||
use crate::mir::ProjectionElem::*;
|
||
|
||
let base = self.base.fold_with(folder);
|
||
let elem = match self.elem {
|
||
Deref => Deref,
|
||
Field(f, ref ty) => Field(f, ty.fold_with(folder)),
|
||
Index(ref v) => Index(v.fold_with(folder)),
|
||
ref elem => elem.clone(),
|
||
};
|
||
|
||
Projection { base, elem }
|
||
}
|
||
|
||
fn super_visit_with<Vs: TypeVisitor<'tcx>>(&self, visitor: &mut Vs) -> bool {
|
||
use crate::mir::ProjectionElem::*;
|
||
|
||
self.base.visit_with(visitor) || match self.elem {
|
||
Field(_, ref ty) => ty.visit_with(visitor),
|
||
Index(ref v) => v.visit_with(visitor),
|
||
_ => false,
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<'tcx> TypeFoldable<'tcx> for Field {
|
||
fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, _: &mut F) -> Self {
|
||
*self
|
||
}
|
||
fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
|
||
false
|
||
}
|
||
}
|
||
|
||
impl<'tcx> TypeFoldable<'tcx> for GeneratorSavedLocal {
|
||
fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, _: &mut F) -> Self {
|
||
*self
|
||
}
|
||
fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> bool {
|
||
false
|
||
}
|
||
}
|
||
|
||
impl<'tcx> TypeFoldable<'tcx> for Constant<'tcx> {
|
||
fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
|
||
Constant {
|
||
span: self.span.clone(),
|
||
ty: self.ty.fold_with(folder),
|
||
user_ty: self.user_ty.fold_with(folder),
|
||
literal: self.literal.fold_with(folder),
|
||
}
|
||
}
|
||
fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
|
||
self.ty.visit_with(visitor) || self.literal.visit_with(visitor)
|
||
}
|
||
}
|