rust/src/librustc_trans/trans/inline.rs

194 lines
7.6 KiB
Rust

// Copyright 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 llvm::{AvailableExternallyLinkage, InternalLinkage, SetLinkage};
use metadata::csearch;
use middle::astencode;
use middle::subst::Substs;
use trans::base::{push_ctxt, trans_item, get_item_val, trans_fn};
use trans::common::*;
use middle::ty;
use syntax::ast;
use syntax::ast_util::local_def;
fn instantiate_inline(ccx: &CrateContext, fn_id: ast::DefId)
-> Option<ast::DefId> {
let _icx = push_ctxt("maybe_instantiate_inline");
match ccx.external().borrow().get(&fn_id) {
Some(&Some(node_id)) => {
// Already inline
debug!("maybe_instantiate_inline({}): already inline as node id {}",
ty::item_path_str(ccx.tcx(), fn_id), node_id);
return Some(local_def(node_id));
}
Some(&None) => {
return None; // Not inlinable
}
None => {
// Not seen yet
}
}
let csearch_result =
csearch::maybe_get_item_ast(
ccx.tcx(), fn_id,
Box::new(|a,b,c,d| astencode::decode_inlined_item(a, b, c, d)));
let inline_id = match csearch_result {
csearch::FoundAst::NotFound => {
ccx.external().borrow_mut().insert(fn_id, None);
return None;
}
csearch::FoundAst::Found(&ast::IIItem(ref item)) => {
ccx.external().borrow_mut().insert(fn_id, Some(item.id));
ccx.external_srcs().borrow_mut().insert(item.id, fn_id);
ccx.stats().n_inlines.set(ccx.stats().n_inlines.get() + 1);
trans_item(ccx, &**item);
let linkage = match item.node {
ast::ItemFn(_, _, _, ref generics, _) => {
if generics.is_type_parameterized() {
// Generics have no symbol, so they can't be given any
// linkage.
None
} else {
if ccx.sess().opts.cg.codegen_units == 1 {
// We could use AvailableExternallyLinkage here,
// but InternalLinkage allows LLVM to optimize more
// aggressively (at the cost of sometimes
// duplicating code).
Some(InternalLinkage)
} else {
// With multiple compilation units, duplicated code
// is more of a problem. Also, `codegen_units > 1`
// means the user is okay with losing some
// performance.
Some(AvailableExternallyLinkage)
}
}
}
ast::ItemConst(..) => None,
_ => unreachable!(),
};
match linkage {
Some(linkage) => {
let g = get_item_val(ccx, item.id);
SetLinkage(g, linkage);
}
None => {}
}
item.id
}
csearch::FoundAst::Found(&ast::IIForeign(ref item)) => {
ccx.external().borrow_mut().insert(fn_id, Some(item.id));
ccx.external_srcs().borrow_mut().insert(item.id, fn_id);
item.id
}
csearch::FoundAst::FoundParent(parent_id, &ast::IIItem(ref item)) => {
ccx.external().borrow_mut().insert(parent_id, Some(item.id));
ccx.external_srcs().borrow_mut().insert(item.id, parent_id);
let mut my_id = 0;
match item.node {
ast::ItemEnum(_, _) => {
let vs_here = ty::enum_variants(ccx.tcx(), local_def(item.id));
let vs_there = ty::enum_variants(ccx.tcx(), parent_id);
for (here, there) in vs_here.iter().zip(vs_there.iter()) {
if there.id == fn_id { my_id = here.id.node; }
ccx.external().borrow_mut().insert(there.id, Some(here.id.node));
}
}
ast::ItemStruct(ref struct_def, _) => {
match struct_def.ctor_id {
None => {}
Some(ctor_id) => {
ccx.external().borrow_mut().insert(fn_id, Some(ctor_id));
my_id = ctor_id;
}
}
}
_ => ccx.sess().bug("maybe_instantiate_inline: item has a \
non-enum, non-struct parent")
}
trans_item(ccx, &**item);
my_id
}
csearch::FoundAst::FoundParent(_, _) => {
ccx.sess().bug("maybe_get_item_ast returned a FoundParent \
with a non-item parent");
}
csearch::FoundAst::Found(&ast::IITraitItem(_, ref trait_item)) => {
ccx.external().borrow_mut().insert(fn_id, Some(trait_item.id));
ccx.external_srcs().borrow_mut().insert(trait_item.id, fn_id);
ccx.stats().n_inlines.set(ccx.stats().n_inlines.get() + 1);
// Associated consts already have to be evaluated in `typeck`, so
// the logic to do that already exists in `middle`. In order to
// reuse that code, it needs to be able to look up the traits for
// inlined items.
let ty_trait_item = ty::impl_or_trait_item(ccx.tcx(), fn_id).clone();
ccx.tcx().impl_or_trait_items.borrow_mut()
.insert(local_def(trait_item.id), ty_trait_item);
// If this is a default method, we can't look up the
// impl type. But we aren't going to translate anyways, so
// don't.
trait_item.id
}
csearch::FoundAst::Found(&ast::IIImplItem(impl_did, ref impl_item)) => {
ccx.external().borrow_mut().insert(fn_id, Some(impl_item.id));
ccx.external_srcs().borrow_mut().insert(impl_item.id, fn_id);
ccx.stats().n_inlines.set(ccx.stats().n_inlines.get() + 1);
// Translate monomorphic impl methods immediately.
if let ast::MethodImplItem(ref sig, ref body) = impl_item.node {
let impl_tpt = ty::lookup_item_type(ccx.tcx(), impl_did);
if impl_tpt.generics.types.is_empty() &&
sig.generics.ty_params.is_empty() {
let empty_substs = ccx.tcx().mk_substs(Substs::trans_empty());
let llfn = get_item_val(ccx, impl_item.id);
trans_fn(ccx,
&sig.decl,
body,
llfn,
empty_substs,
impl_item.id,
&[]);
// Use InternalLinkage so LLVM can optimize more aggressively.
SetLinkage(llfn, InternalLinkage);
}
}
impl_item.id
}
};
Some(local_def(inline_id))
}
pub fn get_local_instance(ccx: &CrateContext, fn_id: ast::DefId)
-> Option<ast::DefId> {
if fn_id.krate == ast::LOCAL_CRATE {
Some(fn_id)
} else {
instantiate_inline(ccx, fn_id)
}
}
pub fn maybe_instantiate_inline(ccx: &CrateContext, fn_id: ast::DefId) -> ast::DefId {
get_local_instance(ccx, fn_id).unwrap_or(fn_id)
}