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// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! MIR datatypes and passes. See [the README](README.md) for details.
use graphviz::IntoCow;
use middle::const_val::ConstVal;
use middle::region;
use rustc_const_math::{ConstUsize, ConstInt, ConstMathErr};
use rustc_data_structures::indexed_vec::{IndexVec, Idx};
use rustc_data_structures::control_flow_graph::dominators::{Dominators, dominators};
use rustc_data_structures::control_flow_graph::{GraphPredecessors, GraphSuccessors};
use rustc_data_structures::control_flow_graph::ControlFlowGraph;
use rustc_serialize as serialize;
use hir::def::CtorKind;
use hir::def_id::DefId;
use ty::subst::{Subst, Substs};
use ty::{self, AdtDef, ClosureSubsts, Region, Ty, TyCtxt, GeneratorInterior};
use ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
use util::ppaux;
use rustc_back::slice;
use hir::{self, InlineAsm};
use std::ascii;
use std::borrow::{Cow};
use std::cell::Ref;
use std::fmt::{self, Debug, Formatter, Write};
use std::{iter, u32};
use std::ops::{Index, IndexMut};
use std::vec::IntoIter;
use syntax::ast::{self, Name};
use syntax_pos::Span;
mod cache;
pub mod tcx;
pub mod visit;
pub mod transform;
pub mod traversal;
/// Types for locals
type LocalDecls<'tcx> = IndexVec<Local, LocalDecl<'tcx>>;
pub trait HasLocalDecls<'tcx> {
fn local_decls(&self) -> &LocalDecls<'tcx>;
}
impl<'tcx> HasLocalDecls<'tcx> for LocalDecls<'tcx> {
fn local_decls(&self) -> &LocalDecls<'tcx> {
self
}
}
impl<'tcx> HasLocalDecls<'tcx> for Mir<'tcx> {
fn local_decls(&self) -> &LocalDecls<'tcx> {
&self.local_decls
}
}
/// Lowered representation of a single function.
#[derive(Clone, RustcEncodable, RustcDecodable, Debug)]
pub struct Mir<'tcx> {
/// List of basic blocks. References to basic block use a newtyped index type `BasicBlock`
/// that indexes into this vector.
basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
/// List of visibility (lexical) scopes; these are referenced by statements
/// and used (eventually) for debuginfo. Indexed by a `VisibilityScope`.
pub visibility_scopes: IndexVec<VisibilityScope, VisibilityScopeData>,
/// Crate-local information for each visibility scope, that can't (and
/// needn't) be tracked across crates.
pub visibility_scope_info: ClearOnDecode<IndexVec<VisibilityScope, VisibilityScopeInfo>>,
/// Rvalues promoted from this function, such as borrows of constants.
/// Each of them is the Mir of a constant with the fn's type parameters
/// in scope, but a separate set of locals.
pub promoted: IndexVec<Promoted, Mir<'tcx>>,
/// Return type of the function.
pub return_ty: Ty<'tcx>,
/// Yield type of the function, if it is a generator.
pub yield_ty: Option<Ty<'tcx>>,
/// Generator drop glue
pub generator_drop: Option<Box<Mir<'tcx>>>,
/// The layout of a generator. Produced by the state transformation.
pub generator_layout: Option<GeneratorLayout<'tcx>>,
/// Declarations of locals.
///
/// The first local is the return value pointer, followed by `arg_count`
/// locals for the function arguments, followed by any user-declared
/// variables and temporaries.
pub local_decls: LocalDecls<'tcx>,
/// Number of arguments this function takes.
///
/// Starting at local 1, `arg_count` locals will be provided by the caller
/// and can be assumed to be initialized.
///
/// If this MIR was built for a constant, this will be 0.
pub arg_count: usize,
/// Names and capture modes of all the closure upvars, assuming
/// the first argument is either the closure or a reference to it.
pub upvar_decls: Vec<UpvarDecl>,
/// Mark an argument local (which must be a tuple) as getting passed as
/// its individual components at the LLVM level.
///
/// This is used for the "rust-call" ABI.
pub spread_arg: Option<Local>,
/// A span representing this MIR, for error reporting
pub span: Span,
/// A cache for various calculations
cache: cache::Cache
}
/// where execution begins
pub const START_BLOCK: BasicBlock = BasicBlock(0);
impl<'tcx> Mir<'tcx> {
pub fn new(basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
visibility_scopes: IndexVec<VisibilityScope, VisibilityScopeData>,
visibility_scope_info: ClearOnDecode<IndexVec<VisibilityScope,
VisibilityScopeInfo>>,
promoted: IndexVec<Promoted, Mir<'tcx>>,
return_ty: Ty<'tcx>,
yield_ty: Option<Ty<'tcx>>,
local_decls: IndexVec<Local, LocalDecl<'tcx>>,
arg_count: usize,
upvar_decls: Vec<UpvarDecl>,
span: Span) -> Self
{
// We need `arg_count` locals, and one for the return pointer
assert!(local_decls.len() >= arg_count + 1,
"expected at least {} locals, got {}", arg_count + 1, local_decls.len());
assert_eq!(local_decls[RETURN_POINTER].ty, return_ty);
Mir {
basic_blocks,
visibility_scopes,
visibility_scope_info,
promoted,
return_ty,
yield_ty,
generator_drop: None,
generator_layout: None,
local_decls,
arg_count,
upvar_decls,
spread_arg: None,
span,
cache: cache::Cache::new()
}
}
#[inline]
pub fn basic_blocks(&self) -> &IndexVec<BasicBlock, BasicBlockData<'tcx>> {
&self.basic_blocks
}
#[inline]
pub fn basic_blocks_mut(&mut self) -> &mut IndexVec<BasicBlock, BasicBlockData<'tcx>> {
self.cache.invalidate();
&mut self.basic_blocks
}
#[inline]
pub fn predecessors(&self) -> Ref<IndexVec<BasicBlock, Vec<BasicBlock>>> {
self.cache.predecessors(self)
}
#[inline]
pub fn predecessors_for(&self, bb: BasicBlock) -> Ref<Vec<BasicBlock>> {
Ref::map(self.predecessors(), |p| &p[bb])
}
#[inline]
pub fn dominators(&self) -> Dominators<BasicBlock> {
dominators(self)
}
#[inline]
pub fn local_kind(&self, local: Local) -> LocalKind {
let index = local.0 as usize;
if index == 0 {
debug_assert!(self.local_decls[local].mutability == Mutability::Mut,
"return pointer should be mutable");
LocalKind::ReturnPointer
} else if index < self.arg_count + 1 {
LocalKind::Arg
} else if self.local_decls[local].name.is_some() {
LocalKind::Var
} else {
debug_assert!(self.local_decls[local].mutability == Mutability::Mut,
"temp should be mutable");
LocalKind::Temp
}
}
/// Returns an iterator over all temporaries.
#[inline]
pub fn temps_iter<'a>(&'a self) -> impl Iterator<Item=Local> + 'a {
(self.arg_count+1..self.local_decls.len()).filter_map(move |index| {
let local = Local::new(index);
if self.local_decls[local].is_user_variable {
None
} else {
Some(local)
}
})
}
/// Returns an iterator over all user-declared locals.
#[inline]
pub fn vars_iter<'a>(&'a self) -> impl Iterator<Item=Local> + 'a {
(self.arg_count+1..self.local_decls.len()).filter_map(move |index| {
let local = Local::new(index);
if self.local_decls[local].is_user_variable {
Some(local)
} else {
None
}
})
}
/// Returns an iterator over all function arguments.
#[inline]
pub fn args_iter(&self) -> impl Iterator<Item=Local> {
let arg_count = self.arg_count;
(1..arg_count+1).map(Local::new)
}
/// Returns an iterator over all user-defined variables and compiler-generated temporaries (all
/// locals that are neither arguments nor the return pointer).
#[inline]
pub fn vars_and_temps_iter(&self) -> impl Iterator<Item=Local> {
let arg_count = self.arg_count;
let local_count = self.local_decls.len();
(arg_count+1..local_count).map(Local::new)
}
/// Changes a statement to a nop. This is both faster than deleting instructions and avoids
/// invalidating statement indices in `Location`s.
pub fn make_statement_nop(&mut self, location: Location) {
let block = &mut self[location.block];
debug_assert!(location.statement_index < block.statements.len());
block.statements[location.statement_index].make_nop()
}
/// Returns the source info associated with `location`.
pub fn source_info(&self, location: Location) -> &SourceInfo {
let block = &self[location.block];
let stmts = &block.statements;
let idx = location.statement_index;
if location.statement_index < stmts.len() {
&stmts[idx].source_info
} else {
assert!(location.statement_index == stmts.len());
&block.terminator().source_info
}
}
}
#[derive(Clone, Debug)]
pub struct VisibilityScopeInfo {
/// A NodeId with lint levels equivalent to this scope's lint levels.
pub lint_root: ast::NodeId,
/// The unsafe block that contains this node.
pub safety: Safety,
}
#[derive(Copy, Clone, Debug)]
pub enum Safety {
Safe,
/// Unsafe because of a PushUnsafeBlock
BuiltinUnsafe,
/// Unsafe because of an unsafe fn
FnUnsafe,
/// Unsafe because of an `unsafe` block
ExplicitUnsafe(ast::NodeId)
}
impl_stable_hash_for!(struct Mir<'tcx> {
basic_blocks,
visibility_scopes,
visibility_scope_info,
promoted,
return_ty,
yield_ty,
generator_drop,
generator_layout,
local_decls,
arg_count,
upvar_decls,
spread_arg,
span,
cache
});
impl<'tcx> Index<BasicBlock> for Mir<'tcx> {
type Output = BasicBlockData<'tcx>;
#[inline]
fn index(&self, index: BasicBlock) -> &BasicBlockData<'tcx> {
&self.basic_blocks()[index]
}
}
impl<'tcx> IndexMut<BasicBlock> for Mir<'tcx> {
#[inline]
fn index_mut(&mut self, index: BasicBlock) -> &mut BasicBlockData<'tcx> {
&mut self.basic_blocks_mut()[index]
}
}
#[derive(Clone, Debug)]
pub enum ClearOnDecode<T> {
Clear,
Set(T)
}
impl<T> serialize::Encodable for ClearOnDecode<T> {
fn encode<S: serialize::Encoder>(&self, s: &mut S) -> Result<(), S::Error> {
serialize::Encodable::encode(&(), s)
}
}
impl<T> serialize::Decodable for ClearOnDecode<T> {
fn decode<D: serialize::Decoder>(d: &mut D) -> Result<Self, D::Error> {
serialize::Decodable::decode(d).map(|()| ClearOnDecode::Clear)
}
}
/// 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)]
pub struct SourceInfo {
/// Source span for the AST pertaining to this MIR entity.
pub span: Span,
/// The lexical visibility scope, i.e. which bindings can be seen.
pub scope: VisibilityScope
}
///////////////////////////////////////////////////////////////////////////
// Mutability and borrow kinds
#[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
pub enum Mutability {
Mut,
Not,
}
#[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
pub enum BorrowKind {
/// Data must be immutable and is aliasable.
Shared,
/// 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 you 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 a `&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,
}
///////////////////////////////////////////////////////////////////////////
// Variables and temps
newtype_index!(Local
{
DEBUG_NAME = "_",
const RETURN_POINTER = 0,
});
/// Classifies locals into categories. See `Mir::local_kind`.
#[derive(PartialEq, Eq, Debug)]
pub enum LocalKind {
/// User-declared variable binding
Var,
/// Compiler-introduced temporary
Temp,
/// Function argument
Arg,
/// Location of function's return value
ReturnPointer,
}
/// A MIR local.
///
/// This can be a binding declared by the user, a temporary inserted by the compiler, a function
/// argument, or the return pointer.
#[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
pub struct LocalDecl<'tcx> {
/// `let mut x` vs `let x`.
///
/// Temporaries and the return pointer are always mutable.
pub mutability: Mutability,
/// True if this corresponds to a user-declared local variable.
pub is_user_variable: bool,
/// 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,
/// Type of this local.
pub ty: Ty<'tcx>,
/// 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>,
/// Source info of the local.
pub source_info: SourceInfo,
/// The *lexical* visibility 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.
pub lexical_scope: VisibilityScope,
}
impl<'tcx> LocalDecl<'tcx> {
/// Create a new `LocalDecl` for a temporary.
#[inline]
pub fn new_temp(ty: Ty<'tcx>, span: Span) -> Self {
LocalDecl {
mutability: Mutability::Mut,
ty,
name: None,
source_info: SourceInfo {
span,
scope: ARGUMENT_VISIBILITY_SCOPE
},
lexical_scope: ARGUMENT_VISIBILITY_SCOPE,
internal: false,
is_user_variable: false
}
}
/// Create a new `LocalDecl` for a internal temporary.
#[inline]
pub fn new_internal(ty: Ty<'tcx>, span: Span) -> Self {
LocalDecl {
mutability: Mutability::Mut,
ty,
name: None,
source_info: SourceInfo {
span,
scope: ARGUMENT_VISIBILITY_SCOPE
},
lexical_scope: ARGUMENT_VISIBILITY_SCOPE,
internal: true,
is_user_variable: false
}
}
/// Builds a `LocalDecl` for the return pointer.
///
/// This must be inserted into the `local_decls` list as the first local.
#[inline]
pub fn new_return_pointer(return_ty: Ty, span: Span) -> LocalDecl {
LocalDecl {
mutability: Mutability::Mut,
ty: return_ty,
source_info: SourceInfo {
span,
scope: ARGUMENT_VISIBILITY_SCOPE
},
lexical_scope: ARGUMENT_VISIBILITY_SCOPE,
internal: false,
name: None, // FIXME maybe we do want some name here?
is_user_variable: false
}
}
}
/// A closure capture, with its name and mode.
#[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
pub struct UpvarDecl {
pub debug_name: Name,
/// If true, the capture is behind a reference.
pub by_ref: bool
}
///////////////////////////////////////////////////////////////////////////
// BasicBlock
newtype_index!(BasicBlock { DEBUG_NAME = "bb" });
///////////////////////////////////////////////////////////////////////////
// BasicBlockData and Terminator
#[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
pub struct BasicBlockData<'tcx> {
/// List of statements in this block.
pub statements: Vec<Statement<'tcx>>,
/// Terminator for this block.
///
/// NB. 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 trans 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)]
pub struct Terminator<'tcx> {
pub source_info: SourceInfo,
pub kind: TerminatorKind<'tcx>
}
#[derive(Clone, RustcEncodable, RustcDecodable)]
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, [ConstInt]>,
/// 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 a normal return. The return pointer lvalue 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 Lvalue
Drop {
location: Lvalue<'tcx>,
target: BasicBlock,
unwind: Option<BasicBlock>
},
/// Drop the Lvalue and assign the new value over it
DropAndReplace {
location: Lvalue<'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
args: Vec<Operand<'tcx>>,
/// Destination for the return value. If some, the call is converging.
destination: Option<(Lvalue<'tcx>, BasicBlock)>,
/// Cleanups to be done if the call unwinds.
cleanup: Option<BasicBlock>
},
/// 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,
}
impl<'tcx> Terminator<'tcx> {
pub fn successors(&self) -> Cow<[BasicBlock]> {
self.kind.successors()
}
pub fn successors_mut(&mut self) -> Vec<&mut BasicBlock> {
self.kind.successors_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 [ConstInt] = &[ConstInt::U8(0)];
TerminatorKind::SwitchInt {
discr: cond,
switch_ty: tcx.types.bool,
values: From::from(BOOL_SWITCH_FALSE),
targets: vec![f, t],
}
}
pub fn successors(&self) -> Cow<[BasicBlock]> {
use self::TerminatorKind::*;
match *self {
Goto { target: ref b } => slice::ref_slice(b).into_cow(),
SwitchInt { targets: ref b, .. } => b[..].into_cow(),
Resume | GeneratorDrop => (&[]).into_cow(),
Return => (&[]).into_cow(),
Unreachable => (&[]).into_cow(),
Call { destination: Some((_, t)), cleanup: Some(c), .. } => vec![t, c].into_cow(),
Call { destination: Some((_, ref t)), cleanup: None, .. } =>
slice::ref_slice(t).into_cow(),
Call { destination: None, cleanup: Some(ref c), .. } => slice::ref_slice(c).into_cow(),
Call { destination: None, cleanup: None, .. } => (&[]).into_cow(),
Yield { resume: t, drop: Some(c), .. } => vec![t, c].into_cow(),
Yield { resume: ref t, drop: None, .. } => slice::ref_slice(t).into_cow(),
DropAndReplace { target, unwind: Some(unwind), .. } |
Drop { target, unwind: Some(unwind), .. } => {
vec![target, unwind].into_cow()
}
DropAndReplace { ref target, unwind: None, .. } |
Drop { ref target, unwind: None, .. } => {
slice::ref_slice(target).into_cow()
}
Assert { target, cleanup: Some(unwind), .. } => vec![target, unwind].into_cow(),
Assert { ref target, .. } => slice::ref_slice(target).into_cow(),
}
}
// FIXME: no mootable cow. I’m honestly not sure what a “cow” between `&mut [BasicBlock]` and
// `Vec<&mut BasicBlock>` would look like in the first place.
pub fn successors_mut(&mut self) -> Vec<&mut BasicBlock> {
use self::TerminatorKind::*;
match *self {
Goto { target: ref mut b } => vec![b],
SwitchInt { targets: ref mut b, .. } => b.iter_mut().collect(),
Resume | GeneratorDrop => Vec::new(),
Return => Vec::new(),
Unreachable => Vec::new(),
Call { destination: Some((_, ref mut t)), cleanup: Some(ref mut c), .. } => vec![t, c],
Call { destination: Some((_, ref mut t)), cleanup: None, .. } => vec![t],
Call { destination: None, cleanup: Some(ref mut c), .. } => vec![c],
Call { destination: None, cleanup: None, .. } => vec![],
Yield { resume: ref mut t, drop: Some(ref mut c), .. } => vec![t, c],
Yield { resume: ref mut t, drop: None, .. } => vec![t],
DropAndReplace { ref mut target, unwind: Some(ref mut unwind), .. } |
Drop { ref mut target, unwind: Some(ref mut unwind), .. } => vec![target, unwind],
DropAndReplace { ref mut target, unwind: None, .. } |
Drop { ref mut target, unwind: None, .. } => {
vec![target]
}
Assert { ref mut target, cleanup: Some(ref mut unwind), .. } => vec![target, unwind],
Assert { ref mut target, .. } => vec![target]
}
}
}
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.kind = StatementKind::Nop;
}
}
}
}
impl<'tcx> Debug for TerminatorKind<'tcx> {
fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
self.fmt_head(fmt)?;
let successors = self.successors();
let labels = self.fmt_successor_labels();
assert_eq!(successors.len(), labels.len());
match successors.len() {
0 => Ok(()),
1 => write!(fmt, " -> {:?}", successors[0]),
_ => {
write!(fmt, " -> [")?;
for (i, target) in successors.iter().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 lv, .. } => write!(fmt, "switchInt({:?})", lv),
Return => write!(fmt, "return"),
GeneratorDrop => write!(fmt, "generator_drop"),
Resume => write!(fmt, "resume"),
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)?;
match *msg {
AssertMessage::BoundsCheck { ref len, ref index } => {
write!(fmt, "{:?}, {:?}, {:?}",
"index out of bounds: the len is {} but the index is {}",
len, index)?;
}
AssertMessage::Math(ref err) => {
write!(fmt, "{:?}", err.description())?;
}
AssertMessage::GeneratorResumedAfterReturn => {
write!(fmt, "{:?}", "generator resumed after completion")?;
}
AssertMessage::GeneratorResumedAfterPanic => {
write!(fmt, "{:?}", "generator resumed after panicking")?;
}
}
write!(fmt, ")")
}
}
}
/// Return 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 | Unreachable | GeneratorDrop => vec![],
Goto { .. } => vec!["".into()],
SwitchInt { ref values, .. } => {
values.iter()
.map(|const_val| {
let mut buf = String::new();
fmt_const_val(&mut buf, &ConstVal::Integral(*const_val)).unwrap();
buf.into()
})
.chain(iter::once(String::from("otherwise").into()))
.collect()
}
Call { destination: Some(_), cleanup: Some(_), .. } =>
vec!["return".into_cow(), "unwind".into_cow()],
Call { destination: Some(_), cleanup: None, .. } => vec!["return".into_cow()],
Call { destination: None, cleanup: Some(_), .. } => vec!["unwind".into_cow()],
Call { destination: None, cleanup: None, .. } => vec![],
Yield { drop: Some(_), .. } =>
vec!["resume".into_cow(), "drop".into_cow()],
Yield { drop: None, .. } => vec!["resume".into_cow()],
DropAndReplace { unwind: None, .. } |
Drop { unwind: None, .. } => vec!["return".into_cow()],
DropAndReplace { unwind: Some(_), .. } |
Drop { unwind: Some(_), .. } => {
vec!["return".into_cow(), "unwind".into_cow()]
}
Assert { cleanup: None, .. } => vec!["".into()],
Assert { .. } =>
vec!["success".into_cow(), "unwind".into_cow()]
}
}
}
#[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
pub enum AssertMessage<'tcx> {
BoundsCheck {
len: Operand<'tcx>,
index: Operand<'tcx>
},
Math(ConstMathErr),
GeneratorResumedAfterReturn,
GeneratorResumedAfterPanic,
}
///////////////////////////////////////////////////////////////////////////
// Statements
#[derive(Clone, RustcEncodable, RustcDecodable)]
pub struct Statement<'tcx> {
pub source_info: SourceInfo,
pub kind: StatementKind<'tcx>,
}
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
}
}
#[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
pub enum StatementKind<'tcx> {
/// Write the RHS Rvalue to the LHS Lvalue.
Assign(Lvalue<'tcx>, Rvalue<'tcx>),
/// Write the discriminant for a variant to the enum Lvalue.
SetDiscriminant { lvalue: Lvalue<'tcx>, variant_index: usize },
/// 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),
/// Execute a piece of inline Assembly.
InlineAsm {
asm: Box<InlineAsm>,
outputs: Vec<Lvalue<'tcx>>,
inputs: Vec<Operand<'tcx>>
},
/// Assert the given lvalues to be valid inhabitants of their type. These statements are
/// currently only interpreted by miri and only generated when "-Z mir-emit-validate" is passed.
/// See <https://internals.rust-lang.org/t/types-as-contracts/5562/73> for more details.
Validate(ValidationOp, Vec<ValidationOperand<'tcx, Lvalue<'tcx>>>),
/// Mark one terminating point of a region scope (i.e. static region).
/// (The starting point(s) arise implicitly from borrows.)
EndRegion(region::Scope),
/// No-op. Useful for deleting instructions without affecting statement indices.
Nop,
}
/// The `ValidationOp` describes what happens with each of the operands of a
/// `Validate` statement.
#[derive(Copy, Clone, RustcEncodable, RustcDecodable, PartialEq, Eq)]
pub enum ValidationOp {
/// Recursively traverse the lvalue following the type and validate that all type
/// invariants are maintained. Furthermore, acquire exclusive/read-only access to the
/// memory reachable from the lvalue.
Acquire,
/// Recursive traverse the *mutable* part of the type and relinquish all exclusive
/// access.
Release,
/// Recursive traverse the *mutable* part of the type and relinquish all exclusive
/// access *until* the given region ends. Then, access will be recovered.
Suspend(region::Scope),
}
impl Debug for ValidationOp {
fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
use self::ValidationOp::*;
match *self {
Acquire => write!(fmt, "Acquire"),
Release => write!(fmt, "Release"),
// (reuse lifetime rendering policy from ppaux.)
Suspend(ref ce) => write!(fmt, "Suspend({})", ty::ReScope(*ce)),
}
}
}
// This is generic so that it can be reused by miri
#[derive(Clone, RustcEncodable, RustcDecodable)]
pub struct ValidationOperand<'tcx, T> {
pub lval: T,
pub ty: Ty<'tcx>,
pub re: Option<region::Scope>,
pub mutbl: hir::Mutability,
}
impl<'tcx, T: Debug> Debug for ValidationOperand<'tcx, T> {
fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
write!(fmt, "{:?}: {:?}", self.lval, self.ty)?;
if let Some(ce) = self.re {
// (reuse lifetime rendering policy from ppaux.)
write!(fmt, "/{}", ty::ReScope(ce))?;
}
if let hir::MutImmutable = self.mutbl {
write!(fmt, " (imm)")?;
}
Ok(())
}
}
impl<'tcx> Debug for Statement<'tcx> {
fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
use self::StatementKind::*;
match self.kind {
Assign(ref lv, ref rv) => write!(fmt, "{:?} = {:?}", lv, rv),
// (reuse lifetime rendering policy from ppaux.)
EndRegion(ref ce) => write!(fmt, "EndRegion({})", ty::ReScope(*ce)),
Validate(ref op, ref lvalues) => write!(fmt, "Validate({:?}, {:?})", op, lvalues),
StorageLive(ref lv) => write!(fmt, "StorageLive({:?})", lv),
StorageDead(ref lv) => write!(fmt, "StorageDead({:?})", lv),
SetDiscriminant{lvalue: ref lv, variant_index: index} => {
write!(fmt, "discriminant({:?}) = {:?}", lv, index)
},
InlineAsm { ref asm, ref outputs, ref inputs } => {
write!(fmt, "asm!({:?} : {:?} : {:?})", asm, outputs, inputs)
},
Nop => write!(fmt, "nop"),
}
}
}
///////////////////////////////////////////////////////////////////////////
// Lvalues
/// A path to a value; something that can be evaluated without
/// changing or disturbing program state.
#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable)]
pub enum Lvalue<'tcx> {
/// local variable
Local(Local),
/// static or static mut variable
Static(Box<Static<'tcx>>),
/// projection out of an lvalue (access a field, deref a pointer, etc)
Projection(Box<LvalueProjection<'tcx>>),
}
/// The def-id of a static, along with its normalized type (which is
/// stored to avoid requiring normalization when reading MIR).
#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable)]
pub struct Static<'tcx> {
pub def_id: DefId,
pub ty: Ty<'tcx>,
}
impl_stable_hash_for!(struct Static<'tcx> {
def_id,
ty
});
/// The `Projection` data structure defines things of the form `B.x`
/// or `*B` or `B[index]`. Note that it is parameterized because it is
/// shared between `Constant` and `Lvalue`. See the aliases
/// `LvalueProjection` etc below.
#[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
pub struct Projection<'tcx, B, V, T> {
pub base: B,
pub elem: ProjectionElem<'tcx, V, T>,
}
#[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
pub enum ProjectionElem<'tcx, 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.
Downcast(&'tcx AdtDef, usize),
}
/// Alias for projections as they appear in lvalues, where the base is an lvalue
/// and the index is a local.
pub type LvalueProjection<'tcx> = Projection<'tcx, Lvalue<'tcx>, Local, Ty<'tcx>>;
/// Alias for projections as they appear in lvalues, where the base is an lvalue
/// and the index is a local.
pub type LvalueElem<'tcx> = ProjectionElem<'tcx, Local, Ty<'tcx>>;
newtype_index!(Field { DEBUG_NAME = "field" });
impl<'tcx> Lvalue<'tcx> {
pub fn field(self, f: Field, ty: Ty<'tcx>) -> Lvalue<'tcx> {
self.elem(ProjectionElem::Field(f, ty))
}
pub fn deref(self) -> Lvalue<'tcx> {
self.elem(ProjectionElem::Deref)
}
pub fn downcast(self, adt_def: &'tcx AdtDef, variant_index: usize) -> Lvalue<'tcx> {
self.elem(ProjectionElem::Downcast(adt_def, variant_index))
}
pub fn index(self, index: Local) -> Lvalue<'tcx> {
self.elem(ProjectionElem::Index(index))
}
pub fn elem(self, elem: LvalueElem<'tcx>) -> Lvalue<'tcx> {
Lvalue::Projection(Box::new(LvalueProjection {
base: self,
elem,
}))
}
}
impl<'tcx> Debug for Lvalue<'tcx> {
fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
use self::Lvalue::*;
match *self {
Local(id) => write!(fmt, "{:?}", id),
Static(box self::Static { def_id, ty }) =>
write!(fmt, "({}: {:?})", ty::tls::with(|tcx| tcx.item_path_str(def_id)), ty),
Projection(ref data) =>
match data.elem {
ProjectionElem::Downcast(ref adt_def, index) =>
write!(fmt, "({:?} as {})", data.base, adt_def.variants[index].name),
ProjectionElem::Deref =>
write!(fmt, "(*{:?})", data.base),
ProjectionElem::Field(field, ty) =>
write!(fmt, "({:?}.{:?}: {:?})", data.base, field.index(), ty),
ProjectionElem::Index(ref index) =>
write!(fmt, "{:?}[{:?}]", data.base, index),
ProjectionElem::ConstantIndex { offset, min_length, from_end: false } =>
write!(fmt, "{:?}[{:?} of {:?}]", data.base, offset, min_length),
ProjectionElem::ConstantIndex { offset, min_length, from_end: true } =>
write!(fmt, "{:?}[-{:?} of {:?}]", data.base, offset, min_length),
ProjectionElem::Subslice { from, to } if to == 0 =>
write!(fmt, "{:?}[{:?}:]", data.base, from),
ProjectionElem::Subslice { from, to } if from == 0 =>
write!(fmt, "{:?}[:-{:?}]", data.base, to),
ProjectionElem::Subslice { from, to } =>
write!(fmt, "{:?}[{:?}:-{:?}]", data.base,
from, to),
},
}
}
}
///////////////////////////////////////////////////////////////////////////
// Scopes
newtype_index!(VisibilityScope
{
DEBUG_NAME = "scope",
const ARGUMENT_VISIBILITY_SCOPE = 0,
});
#[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
pub struct VisibilityScopeData {
pub span: Span,
pub parent_scope: Option<VisibilityScope>,
}
///////////////////////////////////////////////////////////////////////////
// Operands
/// These are values that can appear inside an rvalue (or an index
/// lvalue). They are intentionally limited to prevent rvalues from
/// being nested in one another.
#[derive(Clone, PartialEq, RustcEncodable, RustcDecodable)]
pub enum Operand<'tcx> {
Consume(Lvalue<'tcx>),
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),
Consume(ref lv) => write!(fmt, "{:?}", lv),
}
}
}
impl<'tcx> Operand<'tcx> {
pub fn function_handle<'a>(
tcx: TyCtxt<'a, 'tcx, 'tcx>,
def_id: DefId,
substs: &'tcx Substs<'tcx>,
span: Span,
) -> Self {
let ty = tcx.type_of(def_id).subst(tcx, substs);
Operand::Constant(box Constant {
span,
ty,
literal: Literal::Value {
value: tcx.mk_const(ty::Const {
val: ConstVal::Function(def_id, substs),
ty
})
},
})
}
}
///////////////////////////////////////////////////////////////////////////
/// Rvalues
#[derive(Clone, RustcEncodable, RustcDecodable)]
pub enum Rvalue<'tcx> {
/// x (either a move or copy, depending on type of x)
Use(Operand<'tcx>),
/// [x; 32]
Repeat(Operand<'tcx>, ConstUsize),
/// &x or &mut x
Ref(Region<'tcx>, BorrowKind, Lvalue<'tcx>),
/// length of a [X] or [X;n] value
Len(Lvalue<'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(Lvalue<'tcx>),
/// Create 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)]
pub enum CastKind {
Misc,
/// Convert unique, zero-sized type for a fn to fn()
ReifyFnPointer,
/// Convert non capturing closure to fn()
ClosureFnPointer,
/// Convert safe fn() to unsafe fn()
UnsafeFnPointer,
/// "Unsize" -- convert a thin-or-fat pointer to a fat pointer.
/// trans must figure out the details once full monomorphization
/// is known. For example, this could be used to cast from a
/// `&[i32;N]` to a `&[i32]`, or a `Box<T>` to a `Box<Trait>`
/// (presuming `T: Trait`).
Unsize,
}
#[derive(Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
pub enum AggregateKind<'tcx> {
/// The type is of the element
Array(Ty<'tcx>),
Tuple,
/// The second field is variant number (discriminant), it's equal to 0
/// for struct and union expressions. The fourth field is active field
/// number and is present only for union expressions.
Adt(&'tcx AdtDef, usize, &'tcx Substs<'tcx>, Option<usize>),
Closure(DefId, ClosureSubsts<'tcx>),
Generator(DefId, ClosureSubsts<'tcx>, GeneratorInterior<'tcx>),
}
#[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
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)]
pub enum NullOp {
/// Return the size of a value of that type
SizeOf,
/// Create a new uninitialized box for a value of that type
Box,
}
#[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
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 lvalue) => write!(fmt, "{:?}", lvalue),
Repeat(ref a, ref b) => write!(fmt, "[{:?}; {:?}]", a, b),
Len(ref a) => write!(fmt, "Len({:?})", a),
Cast(ref kind, ref lv, ref ty) => write!(fmt, "{:?} as {:?} ({:?})", lv, 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 lval) => write!(fmt, "discriminant({:?})", lval),
NullaryOp(ref op, ref t) => write!(fmt, "{:?}({:?})", op, t),
Ref(region, borrow_kind, ref lv) => {
let kind_str = match borrow_kind {
BorrowKind::Shared => "",
BorrowKind::Mut | BorrowKind::Unique => "mut ",
};
// When printing regions, add trailing space if necessary.
let region = if ppaux::verbose() || ppaux::identify_regions() {
let mut region = format!("{}", region);
if region.len() > 0 { region.push(' '); }
region
} else {
// Do not even print 'static
"".to_owned()
};
write!(fmt, "&{}{}{:?}", region, kind_str, lv)
}
Aggregate(ref kind, ref lvs) => {
fn fmt_tuple(fmt: &mut Formatter, lvs: &[Operand]) -> fmt::Result {
let mut tuple_fmt = fmt.debug_tuple("");
for lv in lvs {
tuple_fmt.field(lv);
}
tuple_fmt.finish()
}
match **kind {
AggregateKind::Array(_) => write!(fmt, "{:?}", lvs),
AggregateKind::Tuple => {
match lvs.len() {
0 => write!(fmt, "()"),
1 => write!(fmt, "({:?},)", lvs[0]),
_ => fmt_tuple(fmt, lvs),
}
}
AggregateKind::Adt(adt_def, variant, substs, _) => {
let variant_def = &adt_def.variants[variant];
ppaux::parameterized(fmt, substs, variant_def.did, &[])?;
match variant_def.ctor_kind {
CtorKind::Const => Ok(()),
CtorKind::Fn => fmt_tuple(fmt, lvs),
CtorKind::Fictive => {
let mut struct_fmt = fmt.debug_struct("");
for (field, lv) in variant_def.fields.iter().zip(lvs) {
struct_fmt.field(&field.name.as_str(), lv);
}
struct_fmt.finish()
}
}
}
AggregateKind::Closure(def_id, _) => ty::tls::with(|tcx| {
if let Some(node_id) = tcx.hir.as_local_node_id(def_id) {
let name = if tcx.sess.opts.debugging_opts.span_free_formats {
format!("[closure@{:?}]", node_id)
} else {
format!("[closure@{:?}]", tcx.hir.span(node_id))
};
let mut struct_fmt = fmt.debug_struct(&name);
tcx.with_freevars(node_id, |freevars| {
for (freevar, lv) in freevars.iter().zip(lvs) {
let var_name = tcx.hir.name(freevar.var_id());
struct_fmt.field(&var_name.as_str(), lv);
}
});
struct_fmt.finish()
} else {
write!(fmt, "[closure]")
}
}),
AggregateKind::Generator(def_id, _, _) => ty::tls::with(|tcx| {
if let Some(node_id) = tcx.hir.as_local_node_id(def_id) {
let name = format!("[generator@{:?}]", tcx.hir.span(node_id));
let mut struct_fmt = fmt.debug_struct(&name);
tcx.with_freevars(node_id, |freevars| {
for (freevar, lv) in freevars.iter().zip(lvs) {
let var_name = tcx.hir.name(freevar.var_id());
struct_fmt.field(&var_name.as_str(), lv);
}
struct_fmt.field("$state", &lvs[freevars.len()]);
for i in (freevars.len() + 1)..lvs.len() {
struct_fmt.field(&format!("${}", i - freevars.len() - 1),
&lvs[i]);
}
});
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(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
pub struct Constant<'tcx> {
pub span: Span,
pub ty: Ty<'tcx>,
pub literal: Literal<'tcx>,
}
newtype_index!(Promoted { DEBUG_NAME = "promoted" });
#[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
pub enum Literal<'tcx> {
Value {
value: &'tcx ty::Const<'tcx>,
},
Promoted {
// Index into the `promoted` vector of `Mir`.
index: Promoted
},
}
impl<'tcx> Debug for Constant<'tcx> {
fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
write!(fmt, "{:?}", self.literal)
}
}
impl<'tcx> Debug for Literal<'tcx> {
fn fmt(&self, fmt: &mut Formatter) -> fmt::Result {
use self::Literal::*;
match *self {
Value { value } => {
write!(fmt, "const ")?;
fmt_const_val(fmt, &value.val)
}
Promoted { index } => {
write!(fmt, "{:?}", index)
}
}
}
}
/// Write a `ConstVal` in a way closer to the original source code than the `Debug` output.
fn fmt_const_val<W: Write>(fmt: &mut W, const_val: &ConstVal) -> fmt::Result {
use middle::const_val::ConstVal::*;
match *const_val {
Float(f) => write!(fmt, "{:?}", f),
Integral(n) => write!(fmt, "{}", n),
Str(s) => write!(fmt, "{:?}", s),
ByteStr(bytes) => {
let escaped: String = bytes.data
.iter()
.flat_map(|&ch| ascii::escape_default(ch).map(|c| c as char))
.collect();
write!(fmt, "b\"{}\"", escaped)
}
Bool(b) => write!(fmt, "{:?}", b),
Char(c) => write!(fmt, "{:?}", c),
Variant(def_id) |
Function(def_id, _) => write!(fmt, "{}", item_path_str(def_id)),
Aggregate(_) => bug!("`ConstVal::{:?}` should not be in MIR", const_val),
Unevaluated(..) => write!(fmt, "{:?}", const_val)
}
}
fn item_path_str(def_id: DefId) -> String {
ty::tls::with(|tcx| tcx.item_path_str(def_id))
}
impl<'tcx> ControlFlowGraph for Mir<'tcx> {
type Node = BasicBlock;
fn num_nodes(&self) -> usize { self.basic_blocks.len() }
fn start_node(&self) -> Self::Node { START_BLOCK }
fn predecessors<'graph>(&'graph self, node: Self::Node)
-> <Self as GraphPredecessors<'graph>>::Iter
{
self.predecessors_for(node).clone().into_iter()
}
fn successors<'graph>(&'graph self, node: Self::Node)
-> <Self as GraphSuccessors<'graph>>::Iter
{
self.basic_blocks[node].terminator().successors().into_owned().into_iter()
}
}
impl<'a, 'b> GraphPredecessors<'b> for Mir<'a> {
type Item = BasicBlock;
type Iter = IntoIter<BasicBlock>;
}
impl<'a, 'b> GraphSuccessors<'b> for Mir<'a> {
type Item = BasicBlock;
type Iter = IntoIter<BasicBlock>;
}
#[derive(Copy, Clone, PartialEq, Eq, Hash, Ord, PartialOrd)]
pub struct Location {
/// the location is within this block
pub block: BasicBlock,
/// the location is the start of the this 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 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)]
pub struct UnsafetyViolation {
pub source_info: SourceInfo,
pub description: &'static str,
pub lint_node_id: Option<ast::NodeId>,
}
/// The layout of generator state
#[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
pub struct GeneratorLayout<'tcx> {
pub fields: Vec<LocalDecl<'tcx>>,
}
/*
* TypeFoldable implementations for MIR types
*/
impl<'tcx> TypeFoldable<'tcx> for Mir<'tcx> {
fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
Mir {
basic_blocks: self.basic_blocks.fold_with(folder),
visibility_scopes: self.visibility_scopes.clone(),
visibility_scope_info: self.visibility_scope_info.clone(),
promoted: self.promoted.fold_with(folder),
return_ty: self.return_ty.fold_with(folder),
yield_ty: self.yield_ty.fold_with(folder),
generator_drop: self.generator_drop.fold_with(folder),
generator_layout: self.generator_layout.fold_with(folder),
local_decls: self.local_decls.fold_with(folder),
arg_count: self.arg_count,
upvar_decls: self.upvar_decls.clone(),
spread_arg: self.spread_arg,
span: self.span,
cache: cache::Cache::new()
}
}
fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
self.basic_blocks.visit_with(visitor) ||
self.generator_drop.visit_with(visitor) ||
self.generator_layout.visit_with(visitor) ||
self.yield_ty.visit_with(visitor) ||
self.promoted.visit_with(visitor) ||
self.return_ty.visit_with(visitor) ||
self.local_decls.visit_with(visitor)
}
}
impl<'tcx> TypeFoldable<'tcx> for GeneratorLayout<'tcx> {
fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
GeneratorLayout {
fields: self.fields.fold_with(folder),
}
}
fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
self.fields.visit_with(visitor)
}
}
impl<'tcx> TypeFoldable<'tcx> for LocalDecl<'tcx> {
fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
LocalDecl {
ty: self.ty.fold_with(folder),
..self.clone()
}
}
fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
self.ty.visit_with(visitor)
}
}
impl<'tcx> TypeFoldable<'tcx> for BasicBlockData<'tcx> {
fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
BasicBlockData {
statements: self.statements.fold_with(folder),
terminator: self.terminator.fold_with(folder),
is_cleanup: self.is_cleanup
}
}
fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
self.statements.visit_with(visitor) || self.terminator.visit_with(visitor)
}
}
impl<'tcx> TypeFoldable<'tcx> for ValidationOperand<'tcx, Lvalue<'tcx>> {
fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
ValidationOperand {
lval: self.lval.fold_with(folder),
ty: self.ty.fold_with(folder),
re: self.re,
mutbl: self.mutbl,
}
}
fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
self.lval.visit_with(visitor) || self.ty.visit_with(visitor)
}
}
impl<'tcx> TypeFoldable<'tcx> for Statement<'tcx> {
fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
use mir::StatementKind::*;
let kind = match self.kind {
Assign(ref lval, ref rval) => Assign(lval.fold_with(folder), rval.fold_with(folder)),
SetDiscriminant { ref lvalue, variant_index } => SetDiscriminant {
lvalue: lvalue.fold_with(folder),
variant_index,
},
StorageLive(ref local) => StorageLive(local.fold_with(folder)),
StorageDead(ref local) => StorageDead(local.fold_with(folder)),
InlineAsm { ref asm, ref outputs, ref inputs } => InlineAsm {
asm: asm.clone(),
outputs: outputs.fold_with(folder),
inputs: inputs.fold_with(folder)
},
// Note for future: If we want to expose the region scopes
// during the fold, we need to either generalize EndRegion
// to carry `[ty::Region]`, or extend the `TypeFolder`
// trait with a `fn fold_scope`.
EndRegion(ref region_scope) => EndRegion(region_scope.clone()),
Validate(ref op, ref lvals) =>
Validate(op.clone(),
lvals.iter().map(|operand| operand.fold_with(folder)).collect()),
Nop => Nop,
};
Statement {
source_info: self.source_info,
kind,
}
}
fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
use mir::StatementKind::*;
match self.kind {
Assign(ref lval, ref rval) => { lval.visit_with(visitor) || rval.visit_with(visitor) }
SetDiscriminant { ref lvalue, .. } => lvalue.visit_with(visitor),
StorageLive(ref local) |
StorageDead(ref local) => local.visit_with(visitor),
InlineAsm { ref outputs, ref inputs, .. } =>
outputs.visit_with(visitor) || inputs.visit_with(visitor),
// Note for future: If we want to expose the region scopes
// during the visit, we need to either generalize EndRegion
// to carry `[ty::Region]`, or extend the `TypeVisitor`
// trait with a `fn visit_scope`.
EndRegion(ref _scope) => false,
Validate(ref _op, ref lvalues) =>
lvalues.iter().any(|ty_and_lvalue| ty_and_lvalue.visit_with(visitor)),
Nop => false,
}
}
}
impl<'tcx> TypeFoldable<'tcx> for Terminator<'tcx> {
fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
use mir::TerminatorKind::*;
let kind = match self.kind {
Goto { target } => Goto { target: 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 } => {
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,
}
},
Assert { ref cond, expected, ref msg, target, cleanup } => {
let msg = if let AssertMessage::BoundsCheck { ref len, ref index } = *msg {
AssertMessage::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,
Return => Return,
Unreachable => Unreachable,
};
Terminator {
source_info: self.source_info,
kind,
}
}
fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
use 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 AssertMessage::BoundsCheck { ref len, ref index } = *msg {
len.visit_with(visitor) || index.visit_with(visitor)
} else {
false
}
} else {
false
}
},
Goto { .. } |
Resume |
Return |
GeneratorDrop |
Unreachable => false
}
}
}
impl<'tcx> TypeFoldable<'tcx> for Lvalue<'tcx> {
fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
match self {
&Lvalue::Projection(ref p) => Lvalue::Projection(p.fold_with(folder)),
_ => self.clone()
}
}
fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
if let &Lvalue::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 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 lval) => Ref(region.fold_with(folder), bk, lval.fold_with(folder)),
Len(ref lval) => Len(lval.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 lval) => Discriminant(lval.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, n) =>
AggregateKind::Adt(def, v, substs.fold_with(folder), n),
AggregateKind::Closure(id, substs) =>
AggregateKind::Closure(id, substs.fold_with(folder)),
AggregateKind::Generator(id, substs, interior) =>
AggregateKind::Generator(id,
substs.fold_with(folder),
interior.fold_with(folder)),
};
Aggregate(kind, fields.fold_with(folder))
}
}
}
fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
use mir::Rvalue::*;
match *self {
Use(ref op) => op.visit_with(visitor),
Repeat(ref op, _) => op.visit_with(visitor),
Ref(region, _, ref lval) => region.visit_with(visitor) || lval.visit_with(visitor),
Len(ref lval) => lval.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 lval) => lval.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, _) => substs.visit_with(visitor),
AggregateKind::Closure(_, substs) => substs.visit_with(visitor),
AggregateKind::Generator(_, substs, interior) => substs.visit_with(visitor) ||
interior.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::Consume(ref lval) => Operand::Consume(lval.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::Consume(ref lval) => lval.visit_with(visitor),
Operand::Constant(ref c) => c.visit_with(visitor)
}
}
}
impl<'tcx, B, V, T> TypeFoldable<'tcx> for Projection<'tcx, B, V, T>
where B: TypeFoldable<'tcx>, V: TypeFoldable<'tcx>, T: TypeFoldable<'tcx>
{
fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
use 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 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 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),
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)
}
}
impl<'tcx> TypeFoldable<'tcx> for Literal<'tcx> {
fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
match *self {
Literal::Value { value } => Literal::Value {
value: value.fold_with(folder)
},
Literal::Promoted { index } => Literal::Promoted { index }
}
}
fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
match *self {
Literal::Value { value } => value.visit_with(visitor),
Literal::Promoted { .. } => false
}
}
}
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