rust/src/librustc_trans/trans/monomorphize.rs
2016-03-09 16:45:28 +02:00

311 lines
11 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.
use back::link::exported_name;
use llvm::ValueRef;
use llvm;
use middle::def_id::DefId;
use middle::infer::normalize_associated_type;
use middle::subst;
use middle::subst::{Subst, Substs};
use middle::ty::fold::{TypeFolder, TypeFoldable};
use trans::attributes;
use trans::base::{trans_enum_variant, push_ctxt, get_item_val};
use trans::base::trans_fn;
use trans::base;
use trans::common::*;
use trans::declare;
use trans::foreign;
use middle::ty::{self, Ty, TyCtxt};
use trans::Disr;
use rustc::front::map as hir_map;
use rustc_front::hir;
use syntax::abi::Abi;
use syntax::ast;
use syntax::attr;
use syntax::errors;
use std::hash::{Hasher, Hash, SipHasher};
pub fn monomorphic_fn<'a, 'tcx>(ccx: &CrateContext<'a, 'tcx>,
fn_id: DefId,
psubsts: &'tcx subst::Substs<'tcx>)
-> (ValueRef, Ty<'tcx>, bool) {
debug!("monomorphic_fn(fn_id={:?}, real_substs={:?})", fn_id, psubsts);
assert!(!psubsts.types.needs_infer() && !psubsts.types.has_param_types());
// we can only monomorphize things in this crate (or inlined into it)
let fn_node_id = ccx.tcx().map.as_local_node_id(fn_id).unwrap();
let _icx = push_ctxt("monomorphic_fn");
let hash_id = MonoId {
def: fn_id,
params: &psubsts.types
};
let item_ty = ccx.tcx().lookup_item_type(fn_id).ty;
debug!("monomorphic_fn about to subst into {:?}", item_ty);
let mono_ty = apply_param_substs(ccx.tcx(), psubsts, &item_ty);
debug!("mono_ty = {:?} (post-substitution)", mono_ty);
match ccx.monomorphized().borrow().get(&hash_id) {
Some(&val) => {
debug!("leaving monomorphic fn {}",
ccx.tcx().item_path_str(fn_id));
return (val, mono_ty, false);
}
None => ()
}
debug!("monomorphic_fn(\
fn_id={:?}, \
psubsts={:?}, \
hash_id={:?})",
fn_id,
psubsts,
hash_id);
let map_node = errors::expect(
ccx.sess().diagnostic(),
ccx.tcx().map.find(fn_node_id),
|| {
format!("while monomorphizing {:?}, couldn't find it in \
the item map (may have attempted to monomorphize \
an item defined in a different crate?)",
fn_id)
});
if let hir_map::NodeForeignItem(_) = map_node {
let abi = ccx.tcx().map.get_foreign_abi(fn_node_id);
if abi != Abi::RustIntrinsic && abi != Abi::PlatformIntrinsic {
// Foreign externs don't have to be monomorphized.
return (get_item_val(ccx, fn_node_id), mono_ty, true);
}
}
ccx.stats().n_monos.set(ccx.stats().n_monos.get() + 1);
let depth;
{
let mut monomorphizing = ccx.monomorphizing().borrow_mut();
depth = match monomorphizing.get(&fn_id) {
Some(&d) => d, None => 0
};
debug!("monomorphic_fn: depth for fn_id={:?} is {:?}", fn_id, depth+1);
// Random cut-off -- code that needs to instantiate the same function
// recursively more than thirty times can probably safely be assumed
// to be causing an infinite expansion.
if depth > ccx.sess().recursion_limit.get() {
ccx.sess().span_fatal(ccx.tcx().map.span(fn_node_id),
"reached the recursion limit during monomorphization");
}
monomorphizing.insert(fn_id, depth + 1);
}
let hash;
let s = {
let mut state = SipHasher::new();
hash_id.hash(&mut state);
mono_ty.hash(&mut state);
hash = format!("h{}", state.finish());
let path = ccx.tcx().map.def_path_from_id(fn_node_id);
exported_name(path, &hash[..])
};
debug!("monomorphize_fn mangled to {}", s);
// This shouldn't need to option dance.
let mut hash_id = Some(hash_id);
let mut mk_lldecl = |abi: Abi| {
let lldecl = if abi != Abi::Rust {
foreign::decl_rust_fn_with_foreign_abi(ccx, mono_ty, &s)
} else {
// FIXME(nagisa): perhaps needs a more fine grained selection? See
// setup_lldecl below.
declare::define_internal_rust_fn(ccx, &s, mono_ty)
};
ccx.monomorphized().borrow_mut().insert(hash_id.take().unwrap(), lldecl);
lldecl
};
let setup_lldecl = |lldecl, attrs: &[ast::Attribute]| {
base::update_linkage(ccx, lldecl, None, base::OriginalTranslation);
attributes::from_fn_attrs(ccx, attrs, lldecl);
let is_first = !ccx.available_monomorphizations().borrow().contains(&s);
if is_first {
ccx.available_monomorphizations().borrow_mut().insert(s.clone());
}
let trans_everywhere = attr::requests_inline(attrs);
if trans_everywhere && !is_first {
llvm::SetLinkage(lldecl, llvm::AvailableExternallyLinkage);
}
// If `true`, then `lldecl` should be given a function body.
// Otherwise, it should be left as a declaration of an external
// function, with no definition in the current compilation unit.
trans_everywhere || is_first
};
let lldecl = match map_node {
hir_map::NodeItem(i) => {
match *i {
hir::Item {
node: hir::ItemFn(ref decl, _, _, abi, _, ref body),
..
} => {
let d = mk_lldecl(abi);
let needs_body = setup_lldecl(d, &i.attrs);
if needs_body {
if abi != Abi::Rust {
foreign::trans_rust_fn_with_foreign_abi(
ccx, &decl, &body, &[], d, psubsts, fn_node_id,
Some(&hash[..]));
} else {
trans_fn(ccx,
&decl,
&body,
d,
psubsts,
fn_node_id,
&i.attrs);
}
}
d
}
_ => {
ccx.sess().bug("Can't monomorphize this kind of item")
}
}
}
hir_map::NodeVariant(v) => {
let variant = inlined_variant_def(ccx, fn_node_id);
assert_eq!(v.node.name, variant.name);
let d = mk_lldecl(Abi::Rust);
attributes::inline(d, attributes::InlineAttr::Hint);
trans_enum_variant(ccx, fn_node_id, Disr::from(variant.disr_val), psubsts, d);
d
}
hir_map::NodeImplItem(impl_item) => {
match impl_item.node {
hir::ImplItemKind::Method(ref sig, ref body) => {
let d = mk_lldecl(Abi::Rust);
let needs_body = setup_lldecl(d, &impl_item.attrs);
if needs_body {
trans_fn(ccx,
&sig.decl,
body,
d,
psubsts,
impl_item.id,
&impl_item.attrs);
}
d
}
_ => {
ccx.sess().bug(&format!("can't monomorphize a {:?}",
map_node))
}
}
}
hir_map::NodeTraitItem(trait_item) => {
match trait_item.node {
hir::MethodTraitItem(ref sig, Some(ref body)) => {
let d = mk_lldecl(Abi::Rust);
let needs_body = setup_lldecl(d, &trait_item.attrs);
if needs_body {
trans_fn(ccx,
&sig.decl,
body,
d,
psubsts,
trait_item.id,
&trait_item.attrs);
}
d
}
_ => {
ccx.sess().bug(&format!("can't monomorphize a {:?}",
map_node))
}
}
}
hir_map::NodeStructCtor(struct_def) => {
let d = mk_lldecl(Abi::Rust);
attributes::inline(d, attributes::InlineAttr::Hint);
if struct_def.is_struct() {
panic!("ast-mapped struct didn't have a ctor id")
}
base::trans_tuple_struct(ccx,
struct_def.id(),
psubsts,
d);
d
}
// Ugh -- but this ensures any new variants won't be forgotten
hir_map::NodeForeignItem(..) |
hir_map::NodeLifetime(..) |
hir_map::NodeTyParam(..) |
hir_map::NodeExpr(..) |
hir_map::NodeStmt(..) |
hir_map::NodeBlock(..) |
hir_map::NodePat(..) |
hir_map::NodeLocal(..) => {
ccx.sess().bug(&format!("can't monomorphize a {:?}",
map_node))
}
};
ccx.monomorphizing().borrow_mut().insert(fn_id, depth);
debug!("leaving monomorphic fn {}", ccx.tcx().item_path_str(fn_id));
(lldecl, mono_ty, true)
}
#[derive(PartialEq, Eq, Hash, Debug)]
pub struct MonoId<'tcx> {
pub def: DefId,
pub params: &'tcx subst::VecPerParamSpace<Ty<'tcx>>
}
/// Monomorphizes a type from the AST by first applying the in-scope
/// substitutions and then normalizing any associated types.
pub fn apply_param_substs<'tcx,T>(tcx: &TyCtxt<'tcx>,
param_substs: &Substs<'tcx>,
value: &T)
-> T
where T : TypeFoldable<'tcx>
{
let substituted = value.subst(tcx, param_substs);
normalize_associated_type(tcx, &substituted)
}
/// Returns the normalized type of a struct field
pub fn field_ty<'tcx>(tcx: &TyCtxt<'tcx>,
param_substs: &Substs<'tcx>,
f: ty::FieldDef<'tcx>)
-> Ty<'tcx>
{
normalize_associated_type(tcx, &f.ty(tcx, param_substs))
}