rust/src/librustc_metadata/tydecode.rs
2016-05-11 04:14:58 +03:00

729 lines
25 KiB
Rust

// Copyright 2012-2014 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.
// Type decoding
// tjc note: Would be great to have a `match check` macro equivalent
// for some of these
#![allow(non_camel_case_types)]
use rustc::hir;
use rustc::hir::def_id::{DefId, DefIndex};
use middle::region;
use rustc::ty::subst;
use rustc::ty::subst::VecPerParamSpace;
use rustc::ty::{self, ToPredicate, Ty, TyCtxt, TypeFoldable};
use rbml;
use rbml::leb128;
use std::str;
use syntax::abi;
use syntax::ast;
use syntax::parse::token;
// Compact string representation for Ty values. API TyStr &
// parse_from_str. Extra parameters are for converting to/from def_ids in the
// data buffer. Whatever format you choose should not contain pipe characters.
pub type DefIdConvert<'a> = &'a mut FnMut(DefId) -> DefId;
pub struct TyDecoder<'a, 'tcx: 'a> {
data: &'a [u8],
krate: ast::CrateNum,
pos: usize,
tcx: TyCtxt<'a, 'tcx, 'tcx>,
conv_def_id: DefIdConvert<'a>,
}
impl<'a,'tcx> TyDecoder<'a,'tcx> {
pub fn with_doc(tcx: TyCtxt<'a, 'tcx, 'tcx>,
crate_num: ast::CrateNum,
doc: rbml::Doc<'a>,
conv: DefIdConvert<'a>)
-> TyDecoder<'a,'tcx> {
TyDecoder::new(doc.data, crate_num, doc.start, tcx, conv)
}
pub fn new(data: &'a [u8],
crate_num: ast::CrateNum,
pos: usize,
tcx: TyCtxt<'a, 'tcx, 'tcx>,
conv: DefIdConvert<'a>)
-> TyDecoder<'a, 'tcx> {
TyDecoder {
data: data,
krate: crate_num,
pos: pos,
tcx: tcx,
conv_def_id: conv,
}
}
pub fn position(&self) -> usize {
self.pos
}
fn peek(&self) -> char {
self.data[self.pos] as char
}
fn next(&mut self) -> char {
let ch = self.data[self.pos] as char;
self.pos = self.pos + 1;
return ch;
}
fn next_byte(&mut self) -> u8 {
let b = self.data[self.pos];
self.pos = self.pos + 1;
return b;
}
fn scan<F>(&mut self, mut is_last: F) -> &'a [u8]
where F: FnMut(char) -> bool,
{
let start_pos = self.pos;
debug!("scan: '{}' (start)", self.data[self.pos] as char);
while !is_last(self.data[self.pos] as char) {
self.pos += 1;
debug!("scan: '{}'", self.data[self.pos] as char);
}
let end_pos = self.pos;
self.pos += 1;
return &self.data[start_pos..end_pos];
}
fn parse_vuint(&mut self) -> usize {
let (value, bytes_read) = leb128::read_unsigned_leb128(self.data,
self.pos);
self.pos += bytes_read;
value as usize
}
fn parse_name(&mut self, last: char) -> ast::Name {
fn is_last(b: char, c: char) -> bool { return c == b; }
let bytes = self.scan(|a| is_last(last, a));
token::intern(str::from_utf8(bytes).unwrap())
}
fn parse_size(&mut self) -> Option<usize> {
assert_eq!(self.next(), '/');
if self.peek() == '|' {
assert_eq!(self.next(), '|');
None
} else {
let n = self.parse_uint();
assert_eq!(self.next(), '|');
Some(n)
}
}
fn parse_vec_per_param_space<T, F>(&mut self, mut f: F) -> VecPerParamSpace<T> where
F: FnMut(&mut TyDecoder<'a, 'tcx>) -> T,
{
let mut r = VecPerParamSpace::empty();
for &space in &subst::ParamSpace::all() {
assert_eq!(self.next(), '[');
while self.peek() != ']' {
r.push(space, f(self));
}
assert_eq!(self.next(), ']');
}
r
}
pub fn parse_substs(&mut self) -> subst::Substs<'tcx> {
let regions = self.parse_vec_per_param_space(|this| this.parse_region());
let types = self.parse_vec_per_param_space(|this| this.parse_ty());
subst::Substs { types: types, regions: regions }
}
fn parse_bound_region(&mut self) -> ty::BoundRegion {
match self.next() {
'a' => {
let id = self.parse_u32();
assert_eq!(self.next(), '|');
ty::BrAnon(id)
}
'[' => {
let def = self.parse_def();
let name = token::intern(&self.parse_str(']'));
ty::BrNamed(def, name)
}
'f' => {
let id = self.parse_u32();
assert_eq!(self.next(), '|');
ty::BrFresh(id)
}
'e' => ty::BrEnv,
_ => bug!("parse_bound_region: bad input")
}
}
pub fn parse_region(&mut self) -> ty::Region {
match self.next() {
'b' => {
assert_eq!(self.next(), '[');
let id = ty::DebruijnIndex::new(self.parse_u32());
assert_eq!(self.next(), '|');
let br = self.parse_bound_region();
assert_eq!(self.next(), ']');
ty::ReLateBound(id, br)
}
'B' => {
assert_eq!(self.next(), '[');
let space = self.parse_param_space();
assert_eq!(self.next(), '|');
let index = self.parse_u32();
assert_eq!(self.next(), '|');
let name = token::intern(&self.parse_str(']'));
ty::ReEarlyBound(ty::EarlyBoundRegion {
space: space,
index: index,
name: name
})
}
'f' => {
assert_eq!(self.next(), '[');
let scope = self.parse_scope();
assert_eq!(self.next(), '|');
let br = self.parse_bound_region();
assert_eq!(self.next(), ']');
ty::ReFree(ty::FreeRegion { scope: scope,
bound_region: br})
}
's' => {
let scope = self.parse_scope();
assert_eq!(self.next(), '|');
ty::ReScope(scope)
}
't' => {
ty::ReStatic
}
'e' => {
ty::ReStatic
}
_ => bug!("parse_region: bad input")
}
}
fn parse_scope(&mut self) -> region::CodeExtent {
self.tcx.region_maps.bogus_code_extent(match self.next() {
// This creates scopes with the wrong NodeId. This isn't
// actually a problem because scopes only exist *within*
// functions, and functions aren't loaded until trans which
// doesn't care about regions.
//
// May still be worth fixing though.
'C' => {
assert_eq!(self.next(), '[');
let fn_id = self.parse_uint() as ast::NodeId;
assert_eq!(self.next(), '|');
let body_id = self.parse_uint() as ast::NodeId;
assert_eq!(self.next(), ']');
region::CodeExtentData::CallSiteScope {
fn_id: fn_id, body_id: body_id
}
}
// This creates scopes with the wrong NodeId. (See note above.)
'P' => {
assert_eq!(self.next(), '[');
let fn_id = self.parse_uint() as ast::NodeId;
assert_eq!(self.next(), '|');
let body_id = self.parse_uint() as ast::NodeId;
assert_eq!(self.next(), ']');
region::CodeExtentData::ParameterScope {
fn_id: fn_id, body_id: body_id
}
}
'M' => {
let node_id = self.parse_uint() as ast::NodeId;
region::CodeExtentData::Misc(node_id)
}
'D' => {
let node_id = self.parse_uint() as ast::NodeId;
region::CodeExtentData::DestructionScope(node_id)
}
'B' => {
assert_eq!(self.next(), '[');
let node_id = self.parse_uint() as ast::NodeId;
assert_eq!(self.next(), '|');
let first_stmt_index = self.parse_u32();
assert_eq!(self.next(), ']');
let block_remainder = region::BlockRemainder {
block: node_id, first_statement_index: first_stmt_index,
};
region::CodeExtentData::Remainder(block_remainder)
}
_ => bug!("parse_scope: bad input")
})
}
fn parse_opt<T, F>(&mut self, f: F) -> Option<T>
where F: FnOnce(&mut TyDecoder<'a, 'tcx>) -> T,
{
match self.next() {
'n' => None,
's' => Some(f(self)),
_ => bug!("parse_opt: bad input")
}
}
fn parse_str(&mut self, term: char) -> String {
let mut result = String::new();
while self.peek() != term {
unsafe {
result.as_mut_vec().extend_from_slice(&[self.next_byte()])
}
}
self.next();
result
}
pub fn parse_trait_ref(&mut self) -> ty::TraitRef<'tcx> {
let def = self.parse_def();
let substs = self.tcx.mk_substs(self.parse_substs());
ty::TraitRef {def_id: def, substs: substs}
}
pub fn parse_ty(&mut self) -> Ty<'tcx> {
let tcx = self.tcx;
match self.next() {
'b' => return tcx.types.bool,
'i' => { /* eat the s of is */ self.next(); return tcx.types.isize },
'u' => { /* eat the s of us */ self.next(); return tcx.types.usize },
'M' => {
match self.next() {
'b' => return tcx.types.u8,
'w' => return tcx.types.u16,
'l' => return tcx.types.u32,
'd' => return tcx.types.u64,
'B' => return tcx.types.i8,
'W' => return tcx.types.i16,
'L' => return tcx.types.i32,
'D' => return tcx.types.i64,
'f' => return tcx.types.f32,
'F' => return tcx.types.f64,
_ => bug!("parse_ty: bad numeric type")
}
}
'c' => return tcx.types.char,
't' => {
assert_eq!(self.next(), '[');
let did = self.parse_def();
let substs = self.parse_substs();
assert_eq!(self.next(), ']');
let def = self.tcx.lookup_adt_def(did);
return tcx.mk_enum(def, self.tcx.mk_substs(substs));
}
'x' => {
assert_eq!(self.next(), '[');
let trait_ref = ty::Binder(self.parse_trait_ref());
let bounds = self.parse_existential_bounds();
assert_eq!(self.next(), ']');
return tcx.mk_trait(trait_ref, bounds);
}
'p' => {
assert_eq!(self.next(), '[');
let index = self.parse_u32();
assert_eq!(self.next(), '|');
let space = self.parse_param_space();
assert_eq!(self.next(), '|');
let name = token::intern(&self.parse_str(']'));
return tcx.mk_param(space, index, name);
}
'~' => return tcx.mk_box(self.parse_ty()),
'*' => return tcx.mk_ptr(self.parse_mt()),
'&' => {
let r = self.parse_region();
let mt = self.parse_mt();
return tcx.mk_ref(tcx.mk_region(r), mt);
}
'V' => {
let t = self.parse_ty();
return match self.parse_size() {
Some(n) => tcx.mk_array(t, n),
None => tcx.mk_slice(t)
};
}
'v' => {
return tcx.mk_str();
}
'T' => {
assert_eq!(self.next(), '[');
let mut params = Vec::new();
while self.peek() != ']' { params.push(self.parse_ty()); }
self.pos = self.pos + 1;
return tcx.mk_tup(params);
}
'F' => {
let def_id = self.parse_def();
let substs = self.tcx.mk_substs(self.parse_substs());
return tcx.mk_fn_def(def_id, substs, self.parse_bare_fn_ty());
}
'G' => {
return tcx.mk_fn_ptr(self.parse_bare_fn_ty());
}
'#' => {
// This is a hacky little caching scheme. The idea is that if we encode
// the same type twice, the second (and third, and fourth...) time we will
// just write `#123`, where `123` is the offset in the metadata of the
// first appearance. Now when we are *decoding*, if we see a `#123`, we
// can first check a cache (`tcx.rcache`) for that offset. If we find something,
// we return it (modulo closure types, see below). But if not, then we
// jump to offset 123 and read the type from there.
let pos = self.parse_vuint();
let key = ty::CReaderCacheKey { cnum: self.krate, pos: pos };
match tcx.rcache.borrow().get(&key).cloned() {
Some(tt) => {
// If there is a closure buried in the type some where, then we
// need to re-convert any def ids (see case 'k', below). That means
// we can't reuse the cached version.
if !tt.has_closure_types() {
return tt;
}
}
None => {}
}
let mut substate = TyDecoder::new(self.data,
self.krate,
pos,
self.tcx,
self.conv_def_id);
let tt = substate.parse_ty();
tcx.rcache.borrow_mut().insert(key, tt);
return tt;
}
'\"' => {
let _ = self.parse_def();
let inner = self.parse_ty();
inner
}
'a' => {
assert_eq!(self.next(), '[');
let did = self.parse_def();
let substs = self.parse_substs();
assert_eq!(self.next(), ']');
let def = self.tcx.lookup_adt_def(did);
return self.tcx.mk_struct(def, self.tcx.mk_substs(substs));
}
'k' => {
assert_eq!(self.next(), '[');
let did = self.parse_def();
let substs = self.parse_substs();
let mut tys = vec![];
while self.peek() != '.' {
tys.push(self.parse_ty());
}
assert_eq!(self.next(), '.');
assert_eq!(self.next(), ']');
return self.tcx.mk_closure(did, self.tcx.mk_substs(substs), tys);
}
'P' => {
assert_eq!(self.next(), '[');
let trait_ref = self.parse_trait_ref();
let name = token::intern(&self.parse_str(']'));
return tcx.mk_projection(trait_ref, name);
}
'e' => {
return tcx.types.err;
}
c => { bug!("unexpected char in type string: {}", c);}
}
}
fn parse_mutability(&mut self) -> hir::Mutability {
match self.peek() {
'm' => { self.next(); hir::MutMutable }
_ => { hir::MutImmutable }
}
}
fn parse_mt(&mut self) -> ty::TypeAndMut<'tcx> {
let m = self.parse_mutability();
ty::TypeAndMut { ty: self.parse_ty(), mutbl: m }
}
fn parse_def(&mut self) -> DefId {
let def_id = parse_defid(self.scan(|c| c == '|'));
return (self.conv_def_id)(def_id);
}
fn parse_uint(&mut self) -> usize {
let mut n = 0;
loop {
let cur = self.peek();
if cur < '0' || cur > '9' { return n; }
self.pos = self.pos + 1;
n *= 10;
n += (cur as usize) - ('0' as usize);
};
}
fn parse_u32(&mut self) -> u32 {
let n = self.parse_uint();
let m = n as u32;
assert_eq!(m as usize, n);
m
}
fn parse_param_space(&mut self) -> subst::ParamSpace {
subst::ParamSpace::from_uint(self.parse_uint())
}
fn parse_abi_set(&mut self) -> abi::Abi {
assert_eq!(self.next(), '[');
let bytes = self.scan(|c| c == ']');
let abi_str = str::from_utf8(bytes).unwrap();
abi::lookup(&abi_str[..]).expect(abi_str)
}
pub fn parse_closure_ty(&mut self) -> ty::ClosureTy<'tcx> {
let unsafety = parse_unsafety(self.next());
let sig = self.parse_sig();
let abi = self.parse_abi_set();
ty::ClosureTy {
unsafety: unsafety,
sig: sig,
abi: abi,
}
}
pub fn parse_bare_fn_ty(&mut self) -> &'tcx ty::BareFnTy<'tcx> {
let unsafety = parse_unsafety(self.next());
let abi = self.parse_abi_set();
let sig = self.parse_sig();
self.tcx.mk_bare_fn(ty::BareFnTy {
unsafety: unsafety,
abi: abi,
sig: sig
})
}
fn parse_sig(&mut self) -> ty::PolyFnSig<'tcx> {
assert_eq!(self.next(), '[');
let mut inputs = Vec::new();
while self.peek() != ']' {
inputs.push(self.parse_ty());
}
self.pos += 1; // eat the ']'
let variadic = match self.next() {
'V' => true,
'N' => false,
r => bug!("bad variadic: {}", r),
};
let output = match self.peek() {
'z' => {
self.pos += 1;
ty::FnDiverging
}
_ => ty::FnConverging(self.parse_ty())
};
ty::Binder(ty::FnSig {inputs: inputs,
output: output,
variadic: variadic})
}
pub fn parse_predicate(&mut self) -> ty::Predicate<'tcx> {
match self.next() {
't' => ty::Binder(self.parse_trait_ref()).to_predicate(),
'e' => ty::Binder(ty::EquatePredicate(self.parse_ty(),
self.parse_ty())).to_predicate(),
'r' => ty::Binder(ty::OutlivesPredicate(self.parse_region(),
self.parse_region())).to_predicate(),
'o' => ty::Binder(ty::OutlivesPredicate(self.parse_ty(),
self.parse_region())).to_predicate(),
'p' => ty::Binder(self.parse_projection_predicate()).to_predicate(),
'w' => ty::Predicate::WellFormed(self.parse_ty()),
'O' => {
let def_id = self.parse_def();
assert_eq!(self.next(), '|');
ty::Predicate::ObjectSafe(def_id)
}
'c' => {
let def_id = self.parse_def();
assert_eq!(self.next(), '|');
let kind = match self.next() {
'f' => ty::ClosureKind::Fn,
'm' => ty::ClosureKind::FnMut,
'o' => ty::ClosureKind::FnOnce,
c => bug!("Encountered invalid character in metadata: {}", c)
};
assert_eq!(self.next(), '|');
ty::Predicate::ClosureKind(def_id, kind)
}
c => bug!("Encountered invalid character in metadata: {}", c)
}
}
fn parse_projection_predicate(&mut self) -> ty::ProjectionPredicate<'tcx> {
ty::ProjectionPredicate {
projection_ty: ty::ProjectionTy {
trait_ref: self.parse_trait_ref(),
item_name: token::intern(&self.parse_str('|')),
},
ty: self.parse_ty(),
}
}
pub fn parse_type_param_def(&mut self) -> ty::TypeParameterDef<'tcx> {
let name = self.parse_name(':');
let def_id = self.parse_def();
let space = self.parse_param_space();
assert_eq!(self.next(), '|');
let index = self.parse_u32();
assert_eq!(self.next(), '|');
let default_def_id = self.parse_def();
let default = self.parse_opt(|this| this.parse_ty());
let object_lifetime_default = self.parse_object_lifetime_default();
ty::TypeParameterDef {
name: name,
def_id: def_id,
space: space,
index: index,
default_def_id: default_def_id,
default: default,
object_lifetime_default: object_lifetime_default,
}
}
pub fn parse_region_param_def(&mut self) -> ty::RegionParameterDef {
let name = self.parse_name(':');
let def_id = self.parse_def();
let space = self.parse_param_space();
assert_eq!(self.next(), '|');
let index = self.parse_u32();
assert_eq!(self.next(), '|');
let mut bounds = vec![];
loop {
match self.next() {
'R' => bounds.push(self.parse_region()),
'.' => { break; }
c => {
bug!("parse_region_param_def: bad bounds ('{}')", c)
}
}
}
ty::RegionParameterDef {
name: name,
def_id: def_id,
space: space,
index: index,
bounds: bounds
}
}
fn parse_object_lifetime_default(&mut self) -> ty::ObjectLifetimeDefault {
match self.next() {
'a' => ty::ObjectLifetimeDefault::Ambiguous,
'b' => ty::ObjectLifetimeDefault::BaseDefault,
's' => {
let region = self.parse_region();
ty::ObjectLifetimeDefault::Specific(region)
}
_ => bug!("parse_object_lifetime_default: bad input")
}
}
pub fn parse_existential_bounds(&mut self) -> ty::ExistentialBounds<'tcx> {
let builtin_bounds = self.parse_builtin_bounds();
let region_bound = self.parse_region();
let mut projection_bounds = Vec::new();
loop {
match self.next() {
'P' => {
projection_bounds.push(ty::Binder(self.parse_projection_predicate()));
}
'.' => { break; }
c => {
bug!("parse_bounds: bad bounds ('{}')", c)
}
}
}
ty::ExistentialBounds::new(
region_bound, builtin_bounds, projection_bounds)
}
fn parse_builtin_bounds(&mut self) -> ty::BuiltinBounds {
let mut builtin_bounds = ty::BuiltinBounds::empty();
loop {
match self.next() {
'S' => {
builtin_bounds.insert(ty::BoundSend);
}
'Z' => {
builtin_bounds.insert(ty::BoundSized);
}
'P' => {
builtin_bounds.insert(ty::BoundCopy);
}
'T' => {
builtin_bounds.insert(ty::BoundSync);
}
'.' => {
return builtin_bounds;
}
c => {
bug!("parse_bounds: bad builtin bounds ('{}')", c)
}
}
}
}
}
// Rust metadata parsing
fn parse_defid(buf: &[u8]) -> DefId {
let mut colon_idx = 0;
let len = buf.len();
while colon_idx < len && buf[colon_idx] != ':' as u8 { colon_idx += 1; }
if colon_idx == len {
error!("didn't find ':' when parsing def id");
bug!();
}
let crate_part = &buf[0..colon_idx];
let def_part = &buf[colon_idx + 1..len];
let crate_num = match str::from_utf8(crate_part).ok().and_then(|s| {
s.parse::<usize>().ok()
}) {
Some(cn) => cn as ast::CrateNum,
None => bug!("internal error: parse_defid: crate number expected, found {:?}",
crate_part)
};
let def_num = match str::from_utf8(def_part).ok().and_then(|s| {
s.parse::<usize>().ok()
}) {
Some(dn) => dn,
None => bug!("internal error: parse_defid: id expected, found {:?}",
def_part)
};
let index = DefIndex::new(def_num);
DefId { krate: crate_num, index: index }
}
fn parse_unsafety(c: char) -> hir::Unsafety {
match c {
'u' => hir::Unsafety::Unsafe,
'n' => hir::Unsafety::Normal,
_ => bug!("parse_unsafety: bad unsafety {}", c)
}
}