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auto merge of #10217 : alexcrichton/rust/less-reachable, r=pcwalton

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Previously, all functions called by a reachable function were considered
reachable, but this is only the case if the original function was possibly
inlineable (if it's type generic or #[inline]-flagged).
This commit is contained in:
bors 2013-11-02 11:01:16 -07:00
commit 3899f8da6b
4 changed files with 130 additions and 54 deletions
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46
src/librustc/middle/reachable.rs
View file

@ -50,6 +50,7 @@ fn item_might_be_inlined(item: @ast::item) -> bool {
}
match item.node {
ast::item_impl(ref generics, _, _, _) |
ast::item_fn(_, _, _, ref generics, _) => {
generics_require_inlining(generics)
}
@ -64,6 +65,25 @@ fn ty_method_might_be_inlined(ty_method: &ast::TypeMethod) -> bool {
generics_require_inlining(&ty_method.generics)
}
fn method_might_be_inlined(tcx: ty::ctxt, method: &ast::method,
impl_src: ast::DefId) -> bool {
if attributes_specify_inlining(method.attrs) ||
generics_require_inlining(&method.generics) {
return true
}
if is_local(impl_src) {
match tcx.items.find(&impl_src.node) {
Some(&ast_map::node_item(item, _)) => item_might_be_inlined(item),
Some(*) | None => {
tcx.sess.span_bug(method.span, "impl did is not an item")
}
}
} else {
tcx.sess.span_bug(method.span, "found a foreign impl as a parent of a \
local method")
}
}
// Returns true if the given trait method must be inlined because it may be
// monomorphized or it was marked with `#[inline]`.
fn trait_method_might_be_inlined(trait_method: &ast::trait_method) -> bool {
@ -112,8 +132,7 @@ impl Visitor<()> for MarkSymbolVisitor {
let def_id = def_id_of_def(def);
if ReachableContext::
def_id_represents_local_inlined_item(self.tcx,
def_id) {
def_id_represents_local_inlined_item(self.tcx, def_id) {
self.worklist.push(def_id.node)
}
self.reachable_symbols.insert(def_id.node);
@ -145,6 +164,11 @@ impl Visitor<()> for MarkSymbolVisitor {
visit::walk_expr(self, expr, ())
}
fn visit_item(&mut self, _item: @ast::item, _: ()) {
// Do not recurse into items. These items will be added to the worklist
// and recursed into manually if necessary.
}
}
impl ReachableContext {
@ -263,8 +287,11 @@ impl ReachableContext {
Some(&ast_map::node_item(item, _)) => {
match item.node {
ast::item_fn(_, _, _, _, ref search_block) => {
if item_might_be_inlined(item) {
visit::walk_block(&mut visitor, search_block, ())
}
}
// Our recursion into modules involves looking up their
// public reexports and the destinations of those
// exports. Privacy will put them in the worklist, but
@ -331,9 +358,11 @@ impl ReachableContext {
}
}
}
Some(&ast_map::node_method(ref method, _, _)) => {
Some(&ast_map::node_method(method, did, _)) => {
if method_might_be_inlined(self.tcx, method, did) {
visit::walk_block(&mut visitor, &method.body, ())
}
}
// Nothing to recurse on for these
Some(&ast_map::node_foreign_item(*)) |
Some(&ast_map::node_variant(*)) |
@ -378,17 +407,6 @@ pub fn find_reachable(tcx: ty::ctxt,
exp_map2: resolve::ExportMap2,
exported_items: &privacy::ExportedItems)
-> @mut HashSet<ast::NodeId> {
// XXX(pcwalton): We only need to mark symbols that are exported. But this
// is more complicated than just looking at whether the symbol is `pub`,
// because it might be the target of a `pub use` somewhere. For now, I
// think we are fine, because you can't `pub use` something that wasn't
// exported due to the bug whereby `use` only looks through public
// modules even if you're inside the module the `use` appears in. When
// this bug is fixed, however, this code will need to be updated. Probably
// the easiest way to fix this (although a conservative overapproximation)
// is to have the name resolution pass mark all targets of a `pub use` as
// "must be reachable".
let reachable_context = ReachableContext::new(tcx, method_map, exp_map2);
// Step 1: Seed the worklist with all nodes which were found to be public as

10
src/librustc/middle/trans/base.rs
View file

@ -2471,7 +2471,7 @@ pub fn get_item_val(ccx: @mut CrateContext, id: ast::NodeId) -> ValueRef {
match val {
Some(v) => v,
None => {
let mut exprt = false;
let mut foreign = false;
let item = ccx.tcx.items.get_copy(&id);
let val = match item {
ast_map::node_item(i, pth) => {
@ -2584,7 +2584,6 @@ pub fn get_item_val(ccx: @mut CrateContext, id: ast::NodeId) -> ValueRef {
get_item_val()");
}
ast::provided(m) => {
exprt = true;
register_method(ccx, id, pth, m)
}
}
@ -2596,7 +2595,7 @@ pub fn get_item_val(ccx: @mut CrateContext, id: ast::NodeId) -> ValueRef {
ast_map::node_foreign_item(ni, abis, _, pth) => {
let ty = ty::node_id_to_type(ccx.tcx, ni.id);
exprt = true;
foreign = true;
match ni.node {
ast::foreign_item_fn(*) => {
@ -2690,7 +2689,10 @@ pub fn get_item_val(ccx: @mut CrateContext, id: ast::NodeId) -> ValueRef {
}
};
if !exprt && !ccx.reachable.contains(&id) {
// foreign items (extern fns and extern statics) don't have internal
// linkage b/c that doesn't quite make sense. Otherwise items can
// have internal linkage if they're not reachable.
if !foreign && !ccx.reachable.contains(&id) {
lib::llvm::SetLinkage(val, lib::llvm::InternalLinkage);
}

36
src/test/auxiliary/linkage-visibility.rs Normal file
View file

@ -0,0 +1,36 @@
// Copyright 2013 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 std::unstable::dynamic_lib::DynamicLibrary;
#[no_mangle]
pub fn foo() { bar(); }
pub fn foo2<T>() {
fn bar2() {
bar();
}
bar2();
}
#[no_mangle]
fn bar() { }
#[no_mangle]
fn baz() { }
pub fn test() {
let lib = DynamicLibrary::open(None).unwrap();
unsafe {
assert!(lib.symbol::<int>("foo").is_ok());
assert!(lib.symbol::<int>("baz").is_err());
assert!(lib.symbol::<int>("bar").is_err());
}
}

20
src/test/run-pass/linkage-visibility.rs Normal file
View file

@ -0,0 +1,20 @@
// Copyright 2013 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.
// aux-build:linkage-visibility.rs
// xfail-fast windows doesn't like aux-build
extern mod foo(name = "linkage-visibility");
fn main() {
foo::test();
foo::foo2::<int>();
foo::foo();
}