rust/src/librustc/middle/trans/monomorphize.rs
bors e9d0018abf auto merge of #6356 : dotdash/rust/strinterner, r=pcwalton
&str can be turned into @~str on demand, using to_owned(), so for
strings, we can create a specialized interner that accepts &str for
intern() and find() but stores and returns @~str.
2013-05-10 01:55:54 -07:00

409 lines
14 KiB
Rust

// Copyright 2012 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::mangle_exported_name;
use driver::session;
use lib::llvm::ValueRef;
use middle::trans::base::{get_insn_ctxt};
use middle::trans::base::{set_inline_hint_if_appr, set_inline_hint};
use middle::trans::base::{trans_enum_variant};
use middle::trans::base::{trans_fn, decl_internal_cdecl_fn};
use middle::trans::base::{get_item_val, no_self};
use middle::trans::base;
use middle::trans::common::*;
use middle::trans::datum;
use middle::trans::foreign;
use middle::trans::machine;
use middle::trans::meth;
use middle::trans::type_of::type_of_fn_from_ty;
use middle::trans::type_of;
use middle::trans::type_use;
use middle::ty;
use middle::ty::{FnSig};
use middle::typeck;
use util::ppaux::Repr;
use syntax::ast;
use syntax::ast_map;
use syntax::ast_map::path_name;
use syntax::ast_util::local_def;
use syntax::opt_vec;
use syntax::abi::AbiSet;
pub fn monomorphic_fn(ccx: @CrateContext,
fn_id: ast::def_id,
real_substs: &[ty::t],
vtables: Option<typeck::vtable_res>,
impl_did_opt: Option<ast::def_id>,
ref_id: Option<ast::node_id>)
-> (ValueRef, bool)
{
debug!("monomorphic_fn(\
fn_id=%s, \
real_substs=%s, \
vtables=%s, \
impl_did_opt=%s, \
ref_id=%?)",
fn_id.repr(ccx.tcx),
real_substs.repr(ccx.tcx),
vtables.repr(ccx.tcx),
impl_did_opt.repr(ccx.tcx),
ref_id);
assert!(real_substs.all(|t| !ty::type_needs_infer(*t)));
let _icx = ccx.insn_ctxt("monomorphic_fn");
let mut must_cast = false;
let substs = vec::map(real_substs, |t| {
match normalize_for_monomorphization(ccx.tcx, *t) {
Some(t) => { must_cast = true; t }
None => *t
}
});
for real_substs.each() |s| { assert!(!ty::type_has_params(*s)); }
for substs.each() |s| { assert!(!ty::type_has_params(*s)); }
let param_uses = type_use::type_uses_for(ccx, fn_id, substs.len());
// XXX: Bad copy.
let hash_id = make_mono_id(ccx, fn_id, copy substs, vtables, impl_did_opt,
Some(param_uses));
if vec::any(hash_id.params,
|p| match *p { mono_precise(_, _) => false, _ => true }) {
must_cast = true;
}
debug!("monomorphic_fn(\
fn_id=%s, \
vtables=%s, \
substs=%s, \
hash_id=%?)",
fn_id.repr(ccx.tcx),
vtables.repr(ccx.tcx),
substs.repr(ccx.tcx),
hash_id);
match ccx.monomorphized.find(&hash_id) {
Some(&val) => {
debug!("leaving monomorphic fn %s",
ty::item_path_str(ccx.tcx, fn_id));
return (val, must_cast);
}
None => ()
}
let tpt = ty::lookup_item_type(ccx.tcx, fn_id);
let llitem_ty = tpt.ty;
let map_node = session::expect(
ccx.sess,
ccx.tcx.items.find_copy(&fn_id.node),
|| fmt!("While monomorphizing %?, couldn't find it in the item map \
(may have attempted to monomorphize an item \
defined in a different crate?)", fn_id));
// Get the path so that we can create a symbol
let (pt, name, span) = match map_node {
ast_map::node_item(i, pt) => (pt, i.ident, i.span),
ast_map::node_variant(ref v, enm, pt) => (pt, (*v).node.name, enm.span),
ast_map::node_method(m, _, pt) => (pt, m.ident, m.span),
ast_map::node_foreign_item(i, abis, _, pt) if abis.is_intrinsic()
=> (pt, i.ident, i.span),
ast_map::node_foreign_item(*) => {
// Foreign externs don't have to be monomorphized.
return (get_item_val(ccx, fn_id.node), true);
}
ast_map::node_trait_method(@ast::provided(m), _, pt) => {
(pt, m.ident, m.span)
}
ast_map::node_trait_method(@ast::required(_), _, _) => {
ccx.tcx.sess.bug(~"Can't monomorphize a required trait method")
}
ast_map::node_expr(*) => {
ccx.tcx.sess.bug(~"Can't monomorphize an expr")
}
ast_map::node_stmt(*) => {
ccx.tcx.sess.bug(~"Can't monomorphize a stmt")
}
ast_map::node_arg(*) => ccx.tcx.sess.bug(~"Can't monomorphize an arg"),
ast_map::node_block(*) => {
ccx.tcx.sess.bug(~"Can't monomorphize a block")
}
ast_map::node_local(*) => {
ccx.tcx.sess.bug(~"Can't monomorphize a local")
}
ast_map::node_callee_scope(*) => {
ccx.tcx.sess.bug(~"Can't monomorphize a callee-scope")
}
ast_map::node_struct_ctor(_, i, pt) => (pt, i.ident, i.span)
};
// Look up the impl type if we're translating a default method.
// XXX: Generics.
let impl_ty_opt;
match impl_did_opt {
None => impl_ty_opt = None,
Some(impl_did) => {
impl_ty_opt = Some(ty::lookup_item_type(ccx.tcx, impl_did).ty);
}
}
let mono_ty = ty::subst_tps(ccx.tcx, substs, impl_ty_opt, llitem_ty);
let llfty = type_of_fn_from_ty(ccx, mono_ty);
ccx.stats.n_monos += 1;
let depth = match ccx.monomorphizing.find(&fn_id) {
Some(&d) => d, None => 0
};
// 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 > 30 {
ccx.sess.span_fatal(
span, "overly deep expansion of inlined function");
}
ccx.monomorphizing.insert(fn_id, depth + 1);
let pt = vec::append(/*bad*/copy *pt,
~[path_name((ccx.names)(
*ccx.sess.str_of(name)))]);
let s = mangle_exported_name(ccx, /*bad*/copy pt, mono_ty);
let mk_lldecl = || {
let lldecl = decl_internal_cdecl_fn(ccx.llmod, /*bad*/copy s, llfty);
ccx.monomorphized.insert(hash_id, lldecl);
lldecl
};
let psubsts = Some(@param_substs {
tys: substs,
vtables: vtables,
type_param_defs: tpt.generics.type_param_defs,
self_ty: impl_ty_opt
});
let lldecl = match map_node {
ast_map::node_item(i@@ast::item {
node: ast::item_fn(ref decl, _, _, _, ref body),
_
}, _) => {
let d = mk_lldecl();
set_inline_hint_if_appr(/*bad*/copy i.attrs, d);
trans_fn(ccx,
pt,
decl,
body,
d,
no_self,
psubsts,
fn_id.node,
None,
[]);
d
}
ast_map::node_item(*) => {
ccx.tcx.sess.bug(~"Can't monomorphize this kind of item")
}
ast_map::node_foreign_item(i, _, _, _) => {
let d = mk_lldecl();
foreign::trans_intrinsic(ccx, d, i, pt, psubsts.get(), i.attrs,
ref_id);
d
}
ast_map::node_variant(ref v, enum_item, _) => {
let tvs = ty::enum_variants(ccx.tcx, local_def(enum_item.id));
let this_tv = vec::find(*tvs, |tv| { tv.id.node == fn_id.node}).get();
let d = mk_lldecl();
set_inline_hint(d);
match v.node.kind {
ast::tuple_variant_kind(ref args) => {
trans_enum_variant(ccx, enum_item.id, v, /*bad*/copy *args,
this_tv.disr_val, psubsts, d);
}
ast::struct_variant_kind(_) =>
ccx.tcx.sess.bug(~"can't monomorphize struct variants"),
}
d
}
ast_map::node_method(mth, supplied_impl_did, _) => {
// XXX: What should the self type be here?
let d = mk_lldecl();
set_inline_hint_if_appr(/*bad*/copy mth.attrs, d);
// Override the impl def ID if necessary.
let impl_did;
match impl_did_opt {
None => impl_did = supplied_impl_did,
Some(override_impl_did) => impl_did = override_impl_did
}
meth::trans_method(ccx, pt, mth, psubsts, None, d, impl_did);
d
}
ast_map::node_trait_method(@ast::provided(mth), _, pt) => {
let d = mk_lldecl();
set_inline_hint_if_appr(/*bad*/copy mth.attrs, d);
debug!("monomorphic_fn impl_did_opt is %?", impl_did_opt);
meth::trans_method(ccx, /*bad*/copy *pt, mth, psubsts, None, d,
impl_did_opt.get());
d
}
ast_map::node_struct_ctor(struct_def, _, _) => {
let d = mk_lldecl();
set_inline_hint(d);
base::trans_tuple_struct(ccx,
/*bad*/copy struct_def.fields,
struct_def.ctor_id.expect(~"ast-mapped tuple struct \
didn't have a ctor id"),
psubsts,
d);
d
}
// Ugh -- but this ensures any new variants won't be forgotten
ast_map::node_expr(*) |
ast_map::node_stmt(*) |
ast_map::node_trait_method(*) |
ast_map::node_arg(*) |
ast_map::node_block(*) |
ast_map::node_callee_scope(*) |
ast_map::node_local(*) => {
ccx.tcx.sess.bug(fmt!("Can't monomorphize a %?", map_node))
}
};
ccx.monomorphizing.insert(fn_id, depth);
debug!("leaving monomorphic fn %s", ty::item_path_str(ccx.tcx, fn_id));
(lldecl, must_cast)
}
pub fn normalize_for_monomorphization(tcx: ty::ctxt,
ty: ty::t) -> Option<ty::t> {
// FIXME[mono] could do this recursively. is that worthwhile? (#2529)
return match ty::get(ty).sty {
ty::ty_box(*) => {
Some(ty::mk_opaque_box(tcx))
}
ty::ty_bare_fn(_) => {
Some(ty::mk_bare_fn(
tcx,
ty::BareFnTy {
purity: ast::impure_fn,
abis: AbiSet::Rust(),
sig: FnSig {bound_lifetime_names: opt_vec::Empty,
inputs: ~[],
output: ty::mk_nil()}}))
}
ty::ty_closure(ref fty) => {
Some(normalized_closure_ty(tcx, fty.sigil))
}
ty::ty_trait(_, _, ref store, _) => {
let sigil = match *store {
ty::UniqTraitStore => ast::OwnedSigil,
ty::BoxTraitStore => ast::ManagedSigil,
ty::RegionTraitStore(_) => ast::BorrowedSigil,
};
// Traits have the same runtime representation as closures.
Some(normalized_closure_ty(tcx, sigil))
}
ty::ty_ptr(_) => {
Some(ty::mk_uint())
}
_ => {
None
}
};
fn normalized_closure_ty(tcx: ty::ctxt,
sigil: ast::Sigil) -> ty::t
{
ty::mk_closure(
tcx,
ty::ClosureTy {
purity: ast::impure_fn,
sigil: sigil,
onceness: ast::Many,
region: ty::re_static,
sig: ty::FnSig {bound_lifetime_names: opt_vec::Empty,
inputs: ~[],
output: ty::mk_nil()}})
}
}
pub fn make_mono_id(ccx: @CrateContext,
item: ast::def_id,
substs: &[ty::t],
vtables: Option<typeck::vtable_res>,
impl_did_opt: Option<ast::def_id>,
param_uses: Option<@~[type_use::type_uses]>) -> mono_id {
let precise_param_ids = match vtables {
Some(vts) => {
let item_ty = ty::lookup_item_type(ccx.tcx, item);
let mut i = 0;
vec::map_zip(*item_ty.generics.type_param_defs, substs, |type_param_def, subst| {
let mut v = ~[];
for type_param_def.bounds.trait_bounds.each |_bound| {
v.push(meth::vtable_id(ccx, /*bad*/copy vts[i]));
i += 1;
}
(*subst, if !v.is_empty() { Some(v) } else { None })
})
}
None => {
vec::map(substs, |subst| (*subst, None))
}
};
let param_ids = match param_uses {
Some(ref uses) => {
vec::map_zip(precise_param_ids, **uses, |id, uses| {
if ccx.sess.no_monomorphic_collapse() {
match copy *id {
(a, b) => mono_precise(a, b)
}
} else {
match *id {
// XXX: Bad copy.
(a, copy b@Some(_)) => mono_precise(a, b),
(subst, None) => {
if *uses == 0 {
mono_any
} else if *uses == type_use::use_repr &&
!ty::type_needs_drop(ccx.tcx, subst)
{
let llty = type_of::type_of(ccx, subst);
let size = machine::llbitsize_of_real(ccx, llty);
let align = machine::llalign_of_pref(ccx, llty);
let mode = datum::appropriate_mode(subst);
let data_class = mono_data_classify(subst);
// Special value for nil to prevent problems
// with undef return pointers.
if size <= 8u && ty::type_is_nil(subst) {
mono_repr(0u, 0u, data_class, mode)
} else {
mono_repr(size, align, data_class, mode)
}
} else {
mono_precise(subst, None)
}
}
}
}
})
}
None => {
precise_param_ids.map(|x| {
let (a, b) = copy *x;
mono_precise(a, b)
})
}
};
@mono_id_ {def: item, params: param_ids, impl_did_opt: impl_did_opt}
}