rust/src/librustc/middle/trans/monomorphize.rs
Daniel Micay 180e235d3d fix performance regression from invalid IR
Monomorphize's normalization results in a 2% decrease in non-optimized
code size for libstd, so there's a negligible cost to removing it. This
also fixes several visit glue bugs because normalize wasn't considering
the differences in visit glue between types.

Closes #8720
2013-08-23 19:23:54 -04:00

375 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::{set_llvm_fn_attrs, set_inline_hint};
use middle::trans::base::{trans_enum_variant,push_ctxt};
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::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::trans::intrinsic;
use middle::ty;
use middle::typeck;
use util::ppaux::{Repr,ty_to_str};
use syntax::ast;
use syntax::ast_map;
use syntax::ast_map::path_name;
use syntax::ast_util::local_def;
pub fn monomorphic_fn(ccx: @mut CrateContext,
fn_id: ast::def_id,
real_substs: &ty::substs,
vtables: Option<typeck::vtable_res>,
self_vtables: Option<typeck::vtable_param_res>,
ref_id: Option<ast::NodeId>)
-> (ValueRef, bool)
{
debug!("monomorphic_fn(\
fn_id=%s, \
real_substs=%s, \
vtables=%s, \
self_vtable=%s, \
ref_id=%?)",
fn_id.repr(ccx.tcx),
real_substs.repr(ccx.tcx),
vtables.repr(ccx.tcx),
self_vtables.repr(ccx.tcx),
ref_id);
assert!(real_substs.tps.iter().all(|t| !ty::type_needs_infer(*t)));
let _icx = push_ctxt("monomorphic_fn");
let mut must_cast = false;
let psubsts = @param_substs {
tys: real_substs.tps.to_owned(),
vtables: vtables,
self_ty: real_substs.self_ty.clone(),
self_vtables: self_vtables
};
for s in real_substs.tps.iter() { assert!(!ty::type_has_params(*s)); }
for s in psubsts.tys.iter() { assert!(!ty::type_has_params(*s)); }
let param_uses = type_use::type_uses_for(ccx, fn_id, psubsts.tys.len());
let hash_id = make_mono_id(ccx, fn_id, &*psubsts, Some(param_uses));
if hash_id.params.iter().any(
|p| match *p { mono_precise(_, _) => false, _ => true }) {
must_cast = true;
}
debug!("monomorphic_fn(\
fn_id=%s, \
psubsts=%s, \
hash_id=%?)",
fn_id.repr(ccx.tcx),
psubsts.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;
// We need to do special handling of the substitutions if we are
// calling a static provided method. This is sort of unfortunate.
let mut is_static_provided = None;
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) => {
// If this is a static provided method, indicate that
// and stash the number of params on the method.
if m.explicit_self.node == ast::sty_static {
is_static_provided = Some(m.generics.ty_params.len());
}
(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)
};
debug!("monomorphic_fn about to subst into %s", llitem_ty.repr(ccx.tcx));
let mono_ty = match is_static_provided {
None => ty::subst_tps(ccx.tcx, psubsts.tys,
psubsts.self_ty, llitem_ty),
Some(num_method_ty_params) => {
// Static default methods are a little unfortunate, in
// that the "internal" and "external" type of them differ.
// Internally, the method body can refer to Self, but the
// externally visable type of the method has a type param
// inserted in between the trait type params and the
// method type params. The substs that we are given are
// the proper substs *internally* to the method body, so
// we have to use those when compiling it.
//
// In order to get the proper substitution to use on the
// type of the method, we pull apart the substitution and
// stick a substitution for the self type in.
// This is a bit unfortunate.
let idx = psubsts.tys.len() - num_method_ty_params;
let substs =
(psubsts.tys.slice(0, idx) +
&[psubsts.self_ty.unwrap()] +
psubsts.tys.tailn(idx));
debug!("static default: changed substitution to %s",
substs.repr(ccx.tcx));
ty::subst_tps(ccx.tcx, substs, None, 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 elt = path_name(gensym_name(ccx.sess.str_of(name)));
let mut pt = (*pt).clone();
pt.push(elt);
let s = mangle_exported_name(ccx, pt.clone(), mono_ty);
debug!("monomorphize_fn mangled to %s", s);
let mk_lldecl = || {
let lldecl = decl_internal_cdecl_fn(ccx.llmod, s, llfty);
ccx.monomorphized.insert(hash_id, lldecl);
lldecl
};
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_llvm_fn_attrs(i.attrs, d);
trans_fn(ccx,
pt,
decl,
body,
d,
no_self,
Some(psubsts),
fn_id.node,
[]);
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();
intrinsic::trans_intrinsic(ccx, d, i, pt, psubsts, 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 = *tvs.iter().find(|tv| { tv.id.node == fn_id.node}).unwrap();
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,
(*args).clone(),
this_tv.disr_val,
Some(psubsts),
d);
}
ast::struct_variant_kind(_) =>
ccx.tcx.sess.bug("can't monomorphize struct variants"),
}
d
}
ast_map::node_method(mth, _, _) => {
// XXX: What should the self type be here?
let d = mk_lldecl();
set_llvm_fn_attrs(mth.attrs, d);
meth::trans_method(ccx, pt, mth, Some(psubsts), d);
d
}
ast_map::node_trait_method(@ast::provided(mth), _, pt) => {
let d = mk_lldecl();
set_llvm_fn_attrs(mth.attrs, d);
meth::trans_method(ccx, (*pt).clone(), mth, Some(psubsts), d);
d
}
ast_map::node_struct_ctor(struct_def, _, _) => {
let d = mk_lldecl();
set_inline_hint(d);
base::trans_tuple_struct(ccx,
struct_def.fields,
struct_def.ctor_id.expect("ast-mapped tuple struct \
didn't have a ctor id"),
Some(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 make_mono_id(ccx: @mut CrateContext,
item: ast::def_id,
substs: &param_substs,
param_uses: Option<@~[type_use::type_uses]>) -> mono_id {
// FIXME (possibly #5801): Need a lot of type hints to get
// .collect() to work.
let substs_iter = substs.self_ty.iter().chain(substs.tys.iter());
let precise_param_ids: ~[(ty::t, Option<@~[mono_id]>)] = match substs.vtables {
Some(vts) => {
debug!("make_mono_id vtables=%s substs=%s",
vts.repr(ccx.tcx), substs.tys.repr(ccx.tcx));
let vts_iter = substs.self_vtables.iter().chain(vts.iter());
vts_iter.zip(substs_iter).map(|(vtable, subst)| {
let v = vtable.map(|vt| meth::vtable_id(ccx, vt));
(*subst, if !v.is_empty() { Some(@v) } else { None })
}).collect()
}
None => substs_iter.map(|subst| (*subst, None::<@~[mono_id]>)).collect()
};
let param_ids = match param_uses {
Some(ref uses) => {
// param_uses doesn't include a use for the self type.
// We just say it is fully used.
let self_use =
substs.self_ty.map(|_| type_use::use_repr|type_use::use_tydesc);
let uses_iter = self_use.iter().chain(uses.iter());
precise_param_ids.iter().zip(uses_iter).map(|(id, uses)| {
if ccx.sess.no_monomorphic_collapse() {
match *id {
(a, b) => mono_precise(a, b)
}
} else {
match *id {
(a, 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_min(ccx, llty);
let mode = datum::appropriate_mode(ccx.tcx, subst);
let data_class = mono_data_classify(subst);
debug!("make_mono_id: type %s -> size %u align %u mode %? class %?",
ty_to_str(ccx.tcx, subst),
size, align, mode, data_class);
// 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)
}
}
}
}
}).collect()
}
None => {
precise_param_ids.iter().map(|x| {
let (a, b) = *x;
mono_precise(a, b)
}).collect()
}
};
@mono_id_ {def: item, params: param_ids}
}