src/librustc/hir/def_id.rs - third_party/rust - Git at Google

 // Copyright 2012-2015 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.

 use ty;
 use hir::map::definitions::FIRST_FREE_HIGH_DEF_INDEX;
 use rustc_data_structures::indexed_vec::Idx;
 use serialize;
 use std::fmt;
 use std::u32;

 newtype_index! {
     pub struct CrateId {
         ENCODABLE = custom
     }
 }

 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub enum CrateNum {
     /// Virtual crate for builtin macros
     // FIXME(jseyfried): this is also used for custom derives until proc-macro crates get
     // `CrateNum`s.
     BuiltinMacros,
     /// A CrateNum value that indicates that something is wrong.
     Invalid,
     /// A special CrateNum that we use for the tcx.rcache when decoding from
     /// the incr. comp. cache.
     ReservedForIncrCompCache,
     Index(CrateId),
 }

 impl ::std::fmt::Debug for CrateNum {
     fn fmt(&self, fmt: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
         match self {
             CrateNum::Index(id) => write!(fmt, "crate{}", id.private),
             CrateNum::Invalid => write!(fmt, "invalid crate"),
             CrateNum::BuiltinMacros => write!(fmt, "builtin macros crate"),
             CrateNum::ReservedForIncrCompCache => write!(fmt, "crate for decoding incr comp cache"),
         }
     }
 }

 /// Item definitions in the currently-compiled crate would have the CrateNum
 /// LOCAL_CRATE in their DefId.
 pub const LOCAL_CRATE: CrateNum = CrateNum::Index(CrateId::from_u32_const(0));


 impl Idx for CrateNum {
     #[inline]
     fn new(value: usize) -> Self {
         CrateNum::Index(Idx::new(value))
     }

     #[inline]
     fn index(self) -> usize {
         match self {
             CrateNum::Index(idx) => Idx::index(idx),
             _ => bug!("Tried to get crate index of {:?}", self),
         }
     }
 }

 impl CrateNum {
     pub fn new(x: usize) -> CrateNum {
         CrateNum::from_usize(x)
     }

     pub fn from_usize(x: usize) -> CrateNum {
         CrateNum::Index(CrateId::from_usize(x))
     }

     pub fn from_u32(x: u32) -> CrateNum {
         CrateNum::Index(CrateId::from_u32(x))
     }

     pub fn as_usize(self) -> usize {
         match self {
             CrateNum::Index(id) => id.as_usize(),
             _ => bug!("tried to get index of nonstandard crate {:?}", self),
         }
     }

     pub fn as_u32(self) -> u32 {
         match self {
             CrateNum::Index(id) => id.as_u32(),
             _ => bug!("tried to get index of nonstandard crate {:?}", self),
         }
     }

     pub fn as_def_id(&self) -> DefId { DefId { krate: *self, index: CRATE_DEF_INDEX } }
 }

 impl fmt::Display for CrateNum {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             CrateNum::Index(id) => fmt::Display::fmt(&id.private, f),
             CrateNum::Invalid => write!(f, "invalid crate"),
             CrateNum::BuiltinMacros => write!(f, "builtin macros crate"),
             CrateNum::ReservedForIncrCompCache => write!(f, "crate for decoding incr comp cache"),
         }
     }
 }

 impl serialize::UseSpecializedEncodable for CrateNum {}
 impl serialize::UseSpecializedDecodable for CrateNum {}

 /// A DefIndex is an index into the hir-map for a crate, identifying a
 /// particular definition. It should really be considered an interned
 /// shorthand for a particular DefPath.
 ///
 /// At the moment we are allocating the numerical values of DefIndexes from two
 /// address spaces: DefIndexAddressSpace::Low and DefIndexAddressSpace::High.
 /// This allows us to allocate the DefIndexes of all item-likes
 /// (Items, TraitItems, and ImplItems) into one of these spaces and
 /// consequently use a simple array for lookup tables keyed by DefIndex and
 /// known to be densely populated. This is especially important for the HIR map.
 ///
 /// Since the DefIndex is mostly treated as an opaque ID, you probably
 /// don't have to care about these address spaces.

 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Copy)]
 pub struct DefIndex(u32);

 /// The crate root is always assigned index 0 by the AST Map code,
 /// thanks to `NodeCollector::new`.
 pub const CRATE_DEF_INDEX: DefIndex = DefIndex(0);

 impl fmt::Debug for DefIndex {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f,
                "DefIndex({}:{})",
                self.address_space().index(),
                self.as_array_index())
     }
 }

 impl DefIndex {
     #[inline]
     pub fn address_space(&self) -> DefIndexAddressSpace {
         match self.0 & 1 {
             0 => DefIndexAddressSpace::Low,
             1 => DefIndexAddressSpace::High,
             _ => unreachable!()
         }
     }

     /// Converts this DefIndex into a zero-based array index.
     /// This index is the offset within the given DefIndexAddressSpace.
     #[inline]
     pub fn as_array_index(&self) -> usize {
         (self.0 >> 1) as usize
     }

     #[inline]
     pub fn from_array_index(i: usize, address_space: DefIndexAddressSpace) -> DefIndex {
         DefIndex::from_raw_u32(((i << 1) | (address_space as usize)) as u32)
     }

     // Proc macros from a proc-macro crate have a kind of virtual DefIndex. This
     // function maps the index of the macro within the crate (which is also the
     // index of the macro in the CrateMetadata::proc_macros array) to the
     // corresponding DefIndex.
     pub fn from_proc_macro_index(proc_macro_index: usize) -> DefIndex {
         // DefIndex for proc macros start from FIRST_FREE_HIGH_DEF_INDEX,
         // because the first FIRST_FREE_HIGH_DEF_INDEX indexes are reserved
         // for internal use.
         let def_index = DefIndex::from_array_index(
             proc_macro_index.checked_add(FIRST_FREE_HIGH_DEF_INDEX)
                 .expect("integer overflow adding `proc_macro_index`"),
             DefIndexAddressSpace::High);
         assert!(def_index != CRATE_DEF_INDEX);
         def_index
     }

     // This function is the reverse of from_proc_macro_index() above.
     pub fn to_proc_macro_index(self: DefIndex) -> usize {
         assert_eq!(self.address_space(), DefIndexAddressSpace::High);

         self.as_array_index().checked_sub(FIRST_FREE_HIGH_DEF_INDEX)
             .unwrap_or_else(|| {
                 bug!("using local index {:?} as proc-macro index", self)
             })
     }

     // Don't use this if you don't know about the DefIndex encoding.
     pub fn from_raw_u32(x: u32) -> DefIndex {
         DefIndex(x)
     }

     // Don't use this if you don't know about the DefIndex encoding.
     pub fn as_raw_u32(&self) -> u32 {
         self.0
     }
 }

 impl serialize::UseSpecializedEncodable for DefIndex {}
 impl serialize::UseSpecializedDecodable for DefIndex {}

 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
 pub enum DefIndexAddressSpace {
     Low = 0,
     High = 1,
 }

 impl DefIndexAddressSpace {
     #[inline]
     pub fn index(&self) -> usize {
         *self as usize
     }
 }

 /// A `DefId` identifies a particular *definition*, by combining a crate
 /// index and a def index.
 #[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Copy)]
 pub struct DefId {
     pub krate: CrateNum,
     pub index: DefIndex,
 }

 impl fmt::Debug for DefId {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "DefId({}/{}:{}",
                self.krate,
                self.index.address_space().index(),
                self.index.as_array_index())?;

         ty::tls::with_opt(|opt_tcx| {
             if let Some(tcx) = opt_tcx {
                 write!(f, " ~ {}", tcx.def_path_debug_str(*self))?;
             }
             Ok(())
         })?;

         write!(f, ")")
     }
 }

 impl DefId {
     /// Make a local `DefId` with the given index.
     #[inline]
     pub fn local(index: DefIndex) -> DefId {
         DefId { krate: LOCAL_CRATE, index: index }
     }

     #[inline]
     pub fn is_local(self) -> bool {
         self.krate == LOCAL_CRATE
     }

     #[inline]
     pub fn to_local(self) -> LocalDefId {
         LocalDefId::from_def_id(self)
     }
 }

 impl serialize::UseSpecializedEncodable for DefId {}
 impl serialize::UseSpecializedDecodable for DefId {}

 /// A LocalDefId is equivalent to a DefId with `krate == LOCAL_CRATE`. Since
 /// we encode this information in the type, we can ensure at compile time that
 /// no DefIds from upstream crates get thrown into the mix. There are quite a
 /// few cases where we know that only DefIds from the local crate are expected
 /// and a DefId from a different crate would signify a bug somewhere. This
 /// is when LocalDefId comes in handy.
 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
 pub struct LocalDefId(DefIndex);

 impl LocalDefId {
     #[inline]
     pub fn from_def_id(def_id: DefId) -> LocalDefId {
         assert!(def_id.is_local());
         LocalDefId(def_id.index)
     }

     #[inline]
     pub fn to_def_id(self) -> DefId {
         DefId {
             krate: LOCAL_CRATE,
             index: self.0
         }
     }
 }

 impl fmt::Debug for LocalDefId {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         self.to_def_id().fmt(f)
     }
 }

 impl serialize::UseSpecializedEncodable for LocalDefId {}
 impl serialize::UseSpecializedDecodable for LocalDefId {}
	// Copyright 2012-2015 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.

	use ty;
	use hir::map::definitions::FIRST_FREE_HIGH_DEF_INDEX;
	use rustc_data_structures::indexed_vec::Idx;
	use serialize;
	use std::fmt;
	use std::u32;

	newtype_index! {
	pub struct CrateId {
	ENCODABLE = custom
	}
	}

	#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
	pub enum CrateNum {
	/// Virtual crate for builtin macros
	// FIXME(jseyfried): this is also used for custom derives until proc-macro crates get
	// `CrateNum`s.
	BuiltinMacros,
	/// A CrateNum value that indicates that something is wrong.
	Invalid,
	/// A special CrateNum that we use for the tcx.rcache when decoding from
	/// the incr. comp. cache.
	ReservedForIncrCompCache,
	Index(CrateId),
	}

	impl ::std::fmt::Debug for CrateNum {
	fn fmt(&self, fmt: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result {
	match self {
	CrateNum::Index(id) => write!(fmt, "crate{}", id.private),
	CrateNum::Invalid => write!(fmt, "invalid crate"),
	CrateNum::BuiltinMacros => write!(fmt, "builtin macros crate"),
	CrateNum::ReservedForIncrCompCache => write!(fmt, "crate for decoding incr comp cache"),
	}
	}
	}

	/// Item definitions in the currently-compiled crate would have the CrateNum
	/// LOCAL_CRATE in their DefId.
	pub const LOCAL_CRATE: CrateNum = CrateNum::Index(CrateId::from_u32_const(0));


	impl Idx for CrateNum {
	#[inline]
	fn new(value: usize) -> Self {
	CrateNum::Index(Idx::new(value))
	}

	#[inline]
	fn index(self) -> usize {
	match self {
	CrateNum::Index(idx) => Idx::index(idx),
	_ => bug!("Tried to get crate index of {:?}", self),
	}
	}
	}

	impl CrateNum {
	pub fn new(x: usize) -> CrateNum {
	CrateNum::from_usize(x)
	}

	pub fn from_usize(x: usize) -> CrateNum {
	CrateNum::Index(CrateId::from_usize(x))
	}

	pub fn from_u32(x: u32) -> CrateNum {
	CrateNum::Index(CrateId::from_u32(x))
	}

	pub fn as_usize(self) -> usize {
	match self {
	CrateNum::Index(id) => id.as_usize(),
	_ => bug!("tried to get index of nonstandard crate {:?}", self),
	}
	}

	pub fn as_u32(self) -> u32 {
	match self {
	CrateNum::Index(id) => id.as_u32(),
	_ => bug!("tried to get index of nonstandard crate {:?}", self),
	}
	}

	pub fn as_def_id(&self) -> DefId { DefId { krate: *self, index: CRATE_DEF_INDEX } }
	}

	impl fmt::Display for CrateNum {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
	match self {
	CrateNum::Index(id) => fmt::Display::fmt(&id.private, f),
	CrateNum::Invalid => write!(f, "invalid crate"),
	CrateNum::BuiltinMacros => write!(f, "builtin macros crate"),
	CrateNum::ReservedForIncrCompCache => write!(f, "crate for decoding incr comp cache"),
	}
	}
	}

	impl serialize::UseSpecializedEncodable for CrateNum {}
	impl serialize::UseSpecializedDecodable for CrateNum {}

	/// A DefIndex is an index into the hir-map for a crate, identifying a
	/// particular definition. It should really be considered an interned
	/// shorthand for a particular DefPath.
	///
	/// At the moment we are allocating the numerical values of DefIndexes from two
	/// address spaces: DefIndexAddressSpace::Low and DefIndexAddressSpace::High.
	/// This allows us to allocate the DefIndexes of all item-likes
	/// (Items, TraitItems, and ImplItems) into one of these spaces and
	/// consequently use a simple array for lookup tables keyed by DefIndex and
	/// known to be densely populated. This is especially important for the HIR map.
	///
	/// Since the DefIndex is mostly treated as an opaque ID, you probably
	/// don't have to care about these address spaces.

	#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Copy)]
	pub struct DefIndex(u32);

	/// The crate root is always assigned index 0 by the AST Map code,
	/// thanks to `NodeCollector::new`.
	pub const CRATE_DEF_INDEX: DefIndex = DefIndex(0);

	impl fmt::Debug for DefIndex {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
	write!(f,
	"DefIndex({}:{})",
	self.address_space().index(),
	self.as_array_index())
	}
	}

	impl DefIndex {
	#[inline]
	pub fn address_space(&self) -> DefIndexAddressSpace {
	match self.0 & 1 {
	0 => DefIndexAddressSpace::Low,
	1 => DefIndexAddressSpace::High,
	_ => unreachable!()
	}
	}

	/// Converts this DefIndex into a zero-based array index.
	/// This index is the offset within the given DefIndexAddressSpace.
	#[inline]
	pub fn as_array_index(&self) -> usize {
	(self.0 >> 1) as usize
	}

	#[inline]
	pub fn from_array_index(i: usize, address_space: DefIndexAddressSpace) -> DefIndex {
	DefIndex::from_raw_u32(((i << 1) \| (address_space as usize)) as u32)
	}

	// Proc macros from a proc-macro crate have a kind of virtual DefIndex. This
	// function maps the index of the macro within the crate (which is also the
	// index of the macro in the CrateMetadata::proc_macros array) to the
	// corresponding DefIndex.
	pub fn from_proc_macro_index(proc_macro_index: usize) -> DefIndex {
	// DefIndex for proc macros start from FIRST_FREE_HIGH_DEF_INDEX,
	// because the first FIRST_FREE_HIGH_DEF_INDEX indexes are reserved
	// for internal use.
	let def_index = DefIndex::from_array_index(
	proc_macro_index.checked_add(FIRST_FREE_HIGH_DEF_INDEX)
	.expect("integer overflow adding `proc_macro_index`"),
	DefIndexAddressSpace::High);
	assert!(def_index != CRATE_DEF_INDEX);
	def_index
	}

	// This function is the reverse of from_proc_macro_index() above.
	pub fn to_proc_macro_index(self: DefIndex) -> usize {
	assert_eq!(self.address_space(), DefIndexAddressSpace::High);

	self.as_array_index().checked_sub(FIRST_FREE_HIGH_DEF_INDEX)
	.unwrap_or_else(\|\| {
	bug!("using local index {:?} as proc-macro index", self)
	})
	}

	// Don't use this if you don't know about the DefIndex encoding.
	pub fn from_raw_u32(x: u32) -> DefIndex {
	DefIndex(x)
	}

	// Don't use this if you don't know about the DefIndex encoding.
	pub fn as_raw_u32(&self) -> u32 {
	self.0
	}
	}

	impl serialize::UseSpecializedEncodable for DefIndex {}
	impl serialize::UseSpecializedDecodable for DefIndex {}

	#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
	pub enum DefIndexAddressSpace {
	Low = 0,
	High = 1,
	}

	impl DefIndexAddressSpace {
	#[inline]
	pub fn index(&self) -> usize {
	*self as usize
	}
	}

	/// A `DefId` identifies a particular definition, by combining a crate
	/// index and a def index.
	#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Copy)]
	pub struct DefId {
	pub krate: CrateNum,
	pub index: DefIndex,
	}

	impl fmt::Debug for DefId {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
	write!(f, "DefId({}/{}:{}",
	self.krate,
	self.index.address_space().index(),
	self.index.as_array_index())?;

	ty::tls::with_opt(\|opt_tcx\| {
	if let Some(tcx) = opt_tcx {
	write!(f, " ~ {}", tcx.def_path_debug_str(*self))?;
	}
	Ok(())
	})?;

	write!(f, ")")
	}
	}

	impl DefId {
	/// Make a local `DefId` with the given index.
	#[inline]
	pub fn local(index: DefIndex) -> DefId {
	DefId { krate: LOCAL_CRATE, index: index }
	}

	#[inline]
	pub fn is_local(self) -> bool {
	self.krate == LOCAL_CRATE
	}

	#[inline]
	pub fn to_local(self) -> LocalDefId {
	LocalDefId::from_def_id(self)
	}
	}

	impl serialize::UseSpecializedEncodable for DefId {}
	impl serialize::UseSpecializedDecodable for DefId {}

	/// A LocalDefId is equivalent to a DefId with `krate == LOCAL_CRATE`. Since
	/// we encode this information in the type, we can ensure at compile time that
	/// no DefIds from upstream crates get thrown into the mix. There are quite a
	/// few cases where we know that only DefIds from the local crate are expected
	/// and a DefId from a different crate would signify a bug somewhere. This
	/// is when LocalDefId comes in handy.
	#[derive(Clone, Copy, PartialEq, Eq, Hash)]
	pub struct LocalDefId(DefIndex);

	impl LocalDefId {
	#[inline]
	pub fn from_def_id(def_id: DefId) -> LocalDefId {
	assert!(def_id.is_local());
	LocalDefId(def_id.index)
	}

	#[inline]
	pub fn to_def_id(self) -> DefId {
	DefId {
	krate: LOCAL_CRATE,
	index: self.0
	}
	}
	}

	impl fmt::Debug for LocalDefId {
	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
	self.to_def_id().fmt(f)
	}
	}

	impl serialize::UseSpecializedEncodable for LocalDefId {}
	impl serialize::UseSpecializedDecodable for LocalDefId {}