Only instantiate inline- and const-fns if they are referenced (again).

src/librustc/dep_graph/graph.rs

@@ -328,7 +328,12 @@ impl DepGraph {
     }
 
     pub fn fingerprint_of(&self, dep_node: &DepNode) -> Fingerprint {
-        self.fingerprints.borrow()[dep_node]
+        match self.fingerprints.borrow().get(dep_node) {
+            Some(&fingerprint) => fingerprint,
+            None => {
+                bug!("Could not find current fingerprint for {:?}", dep_node)
+            }
+        }
     }
 
     pub fn prev_fingerprint_of(&self, dep_node: &DepNode) -> Option<Fingerprint> {

src/librustc_trans_utils/collector.rs

@@ -211,6 +211,8 @@ use trans_item::{TransItemExt, DefPathBasedNames, InstantiationMode};
 
 use rustc_data_structures::bitvec::BitVector;
 
+use syntax::attr;
+
 #[derive(PartialEq, Eq, Hash, Clone, Copy, Debug)]
 pub enum TransItemCollectionMode {
     Eager,
@@ -324,9 +326,14 @@ fn collect_roots<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
     let mut roots = Vec::new();
 
     {
+        let entry_fn = tcx.sess.entry_fn.borrow().map(|(node_id, _)| {
+            tcx.hir.local_def_id(node_id)
+        });
+
         let mut visitor = RootCollector {
             tcx,
             mode,
+            entry_fn,
             output: &mut roots,
         };
 
@@ -875,6 +882,7 @@ struct RootCollector<'b, 'a: 'b, 'tcx: 'a + 'b> {
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
     mode: TransItemCollectionMode,
     output: &'b mut Vec<TransItem<'tcx>>,
+    entry_fn: Option<DefId>,
 }
 
 impl<'b, 'a, 'v> ItemLikeVisitor<'v> for RootCollector<'b, 'a, 'v> {
@@ -932,10 +940,7 @@ impl<'b, 'a, 'v> ItemLikeVisitor<'v> for RootCollector<'b, 'a, 'v> {
                 let tcx = self.tcx;
                 let def_id = tcx.hir.local_def_id(item.id);
 
-                if (self.mode == TransItemCollectionMode::Eager ||
-                    !tcx.is_const_fn(def_id) || tcx.is_exported_symbol(def_id)) &&
-                   !item_has_type_parameters(tcx, def_id) {
-
+                if self.is_root(def_id) {
                     debug!("RootCollector: ItemFn({})",
                            def_id_to_string(tcx, def_id));
 
@@ -957,10 +962,7 @@ impl<'b, 'a, 'v> ItemLikeVisitor<'v> for RootCollector<'b, 'a, 'v> {
                 let tcx = self.tcx;
                 let def_id = tcx.hir.local_def_id(ii.id);
 
-                if (self.mode == TransItemCollectionMode::Eager ||
-                    !tcx.is_const_fn(def_id) ||
-                    tcx.is_exported_symbol(def_id)) &&
-                   !item_has_type_parameters(tcx, def_id) {
+                if self.is_root(def_id) {
                     debug!("RootCollector: MethodImplItem({})",
                            def_id_to_string(tcx, def_id));
 
@@ -973,6 +975,22 @@ impl<'b, 'a, 'v> ItemLikeVisitor<'v> for RootCollector<'b, 'a, 'v> {
     }
 }
 
+impl<'b, 'a, 'v> RootCollector<'b, 'a, 'v> {
+    fn is_root(&self, def_id: DefId) -> bool {
+        !item_has_type_parameters(self.tcx, def_id) && match self.mode {
+            TransItemCollectionMode::Eager => {
+                true
+            }
+            TransItemCollectionMode::Lazy => {
+                self.entry_fn == Some(def_id) ||
+                self.tcx.is_exported_symbol(def_id) ||
+                attr::contains_name(&self.tcx.get_attrs(def_id),
+                                    "rustc_std_internal_symbol")
+            }
+        }
+    }
+}
+
 fn item_has_type_parameters<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) -> bool {
     let generics = tcx.generics_of(def_id);
     generics.parent_types as usize + generics.types.len() > 0

src/librustc_trans_utils/common.rs

@@ -51,7 +51,8 @@ pub fn requests_inline<'a, 'tcx>(
         // available to normal end-users.
         return true
     }
-    attr::requests_inline(&instance.def.attrs(tcx)[..])
+    attr::requests_inline(&instance.def.attrs(tcx)[..]) ||
+        tcx.is_const_fn(instance.def.def_id())
 }
 
 pub fn is_inline_instance<'a, 'tcx>(

src/librustc_trans_utils/lib.rs

@@ -40,14 +40,12 @@ extern crate rustc_data_structures;
 extern crate syntax;
 extern crate syntax_pos;
 
-use rustc::ty::TyCtxt;
+use rustc::ty::{TyCtxt, Instance};
 use rustc::hir;
 use rustc::hir::def_id::LOCAL_CRATE;
 use rustc::hir::map as hir_map;
 use rustc::util::nodemap::NodeSet;
 
-use syntax::attr;
-
 pub mod common;
 pub mod link;
 pub mod collector;
@@ -77,7 +75,7 @@ pub fn check_for_rustc_errors_attr(tcx: TyCtxt) {
 ///
 /// This list is later used by linkers to determine the set of symbols needed to
 /// be exposed from a dynamic library and it's also encoded into the metadata.
-pub fn find_exported_symbols(tcx: TyCtxt) -> NodeSet {
+pub fn find_exported_symbols<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>) -> NodeSet {
     tcx.reachable_set(LOCAL_CRATE).0.iter().cloned().filter(|&id| {
         // Next, we want to ignore some FFI functions that are not exposed from
         // this crate. Reachable FFI functions can be lumped into two
@@ -107,11 +105,10 @@ pub fn find_exported_symbols(tcx: TyCtxt) -> NodeSet {
                 node: hir::ImplItemKind::Method(..), .. }) => {
                 let def_id = tcx.hir.local_def_id(id);
                 let generics = tcx.generics_of(def_id);
-                let attributes = tcx.get_attrs(def_id);
                 (generics.parent_types == 0 && generics.types.is_empty()) &&
                 // Functions marked with #[inline] are only ever translated
                 // with "internal" linkage and are never exported.
-                !attr::requests_inline(&attributes)
+                !common::requests_inline(tcx, &Instance::mono(tcx, def_id))
             }
 
             _ => false

src/test/codegen-units/item-collection/unreferenced-const-fn.rs

@@ -0,0 +1,22 @@
+// Copyright 2017 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.
+
+// ignore-tidy-linelength
+// compile-flags:-Zprint-trans-items=lazy
+
+// NB: We do not expect *any* translation item to be generated here.
+
+#![feature(const_fn)]
+#![deny(dead_code)]
+#![crate_type = "rlib"]
+
+pub const fn foo(x: u32) -> u32 {
+    x + 0xf00
+}

src/test/codegen-units/item-collection/unreferenced-inline-function.rs

@@ -0,0 +1,23 @@
+// Copyright 2017 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.
+
+// ignore-tidy-linelength
+// compile-flags:-Zprint-trans-items=lazy
+
+// NB: We do not expect *any* translation item to be generated here.
+
+#![deny(dead_code)]
+#![crate_type = "rlib"]
+
+#[inline]
+pub fn foo() -> bool {
+    [1, 2] == [3, 4]
+}
+

src/test/codegen-units/partitioning/extern-drop-glue.rs

@@ -16,7 +16,7 @@
 // compile-flags:-Zinline-in-all-cgus
 
 #![allow(dead_code)]
-#![crate_type="lib"]
+#![crate_type="rlib"]
 
 // aux-build:cgu_extern_drop_glue.rs
 extern crate cgu_extern_drop_glue;
@@ -25,20 +25,20 @@ extern crate cgu_extern_drop_glue;
 
 struct LocalStruct(cgu_extern_drop_glue::Struct);
 
-//~ TRANS_ITEM fn extern_drop_glue::user[0] @@ extern_drop_glue[Internal]
-fn user()
+//~ TRANS_ITEM fn extern_drop_glue::user[0] @@ extern_drop_glue[External]
+pub fn user()
 {
     //~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<extern_drop_glue::LocalStruct[0]> @@ extern_drop_glue[Internal]
     let _ = LocalStruct(cgu_extern_drop_glue::Struct(0));
 }
 
-mod mod1 {
+pub mod mod1 {
     use cgu_extern_drop_glue;
 
     struct LocalStruct(cgu_extern_drop_glue::Struct);
 
-    //~ TRANS_ITEM fn extern_drop_glue::mod1[0]::user[0] @@ extern_drop_glue-mod1[Internal]
-    fn user()
+    //~ TRANS_ITEM fn extern_drop_glue::mod1[0]::user[0] @@ extern_drop_glue-mod1[External]
+    pub fn user()
     {
         //~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<extern_drop_glue::mod1[0]::LocalStruct[0]> @@ extern_drop_glue-mod1[Internal]
         let _ = LocalStruct(cgu_extern_drop_glue::Struct(0));

src/test/codegen-units/partitioning/inlining-from-extern-crate.rs

@@ -35,10 +35,10 @@ pub fn user()
     cgu_explicit_inlining::never_inlined();
 }
 
-mod mod1 {
+pub mod mod1 {
     use cgu_explicit_inlining;
 
-    //~ TRANS_ITEM fn inlining_from_extern_crate::mod1[0]::user[0] @@ inlining_from_extern_crate-mod1[Internal]
+    //~ TRANS_ITEM fn inlining_from_extern_crate::mod1[0]::user[0] @@ inlining_from_extern_crate-mod1[External]
     pub fn user()
     {
         cgu_explicit_inlining::inlined();
@@ -48,10 +48,10 @@ mod mod1 {
     }
 }
 
-mod mod2 {
+pub mod mod2 {
     use cgu_explicit_inlining;
 
-    //~ TRANS_ITEM fn inlining_from_extern_crate::mod2[0]::user[0] @@ inlining_from_extern_crate-mod2[Internal]
+    //~ TRANS_ITEM fn inlining_from_extern_crate::mod2[0]::user[0] @@ inlining_from_extern_crate-mod2[External]
     pub fn user()
     {
         cgu_explicit_inlining::always_inlined();

src/test/codegen-units/partitioning/local-drop-glue.rs

@@ -15,7 +15,7 @@
 // compile-flags:-Zinline-in-all-cgus
 
 #![allow(dead_code)]
-#![crate_type="lib"]
+#![crate_type="rlib"]
 
 //~ TRANS_ITEM fn core::ptr[0]::drop_in_place[0]<local_drop_glue::Struct[0]> @@ local_drop_glue[Internal] local_drop_glue-mod1[Internal]
 struct Struct {
@@ -32,8 +32,8 @@ struct Outer {
     _a: Struct
 }
 
-//~ TRANS_ITEM fn local_drop_glue::user[0] @@ local_drop_glue[Internal]
-fn user()
+//~ TRANS_ITEM fn local_drop_glue::user[0] @@ local_drop_glue[External]
+pub fn user()
 {
     let _ = Outer {
         _a: Struct {
@@ -42,7 +42,7 @@ fn user()
     };
 }
 
-mod mod1
+pub mod mod1
 {
     use super::Struct;
 
@@ -53,8 +53,8 @@ mod mod1
         _b: (u32, Struct),
     }
 
-    //~ TRANS_ITEM fn local_drop_glue::mod1[0]::user[0] @@ local_drop_glue-mod1[Internal]
-    fn user()
+    //~ TRANS_ITEM fn local_drop_glue::mod1[0]::user[0] @@ local_drop_glue-mod1[External]
+    pub fn user()
     {
         let _ = Struct2 {
             _a: Struct { _a: 0 },

src/test/codegen-units/partitioning/local-inlining-but-not-all.rs

@@ -27,28 +27,28 @@ mod inline {
     }
 }
 
-mod user1 {
+pub mod user1 {
     use super::inline;
 
-    //~ TRANS_ITEM fn local_inlining_but_not_all::user1[0]::foo[0] @@ local_inlining_but_not_all-user1[Internal]
-    fn foo() {
+    //~ TRANS_ITEM fn local_inlining_but_not_all::user1[0]::foo[0] @@ local_inlining_but_not_all-user1[External]
+    pub fn foo() {
         inline::inlined_function();
     }
 }
 
-mod user2 {
+pub mod user2 {
     use super::inline;
 
-    //~ TRANS_ITEM fn local_inlining_but_not_all::user2[0]::bar[0] @@ local_inlining_but_not_all-user2[Internal]
-    fn bar() {
+    //~ TRANS_ITEM fn local_inlining_but_not_all::user2[0]::bar[0] @@ local_inlining_but_not_all-user2[External]
+    pub fn bar() {
         inline::inlined_function();
     }
 }
 
-mod non_user {
+pub mod non_user {
 
-    //~ TRANS_ITEM fn local_inlining_but_not_all::non_user[0]::baz[0] @@ local_inlining_but_not_all-non_user[Internal]
-    fn baz() {
+    //~ TRANS_ITEM fn local_inlining_but_not_all::non_user[0]::baz[0] @@ local_inlining_but_not_all-non_user[External]
+    pub fn baz() {
 
     }
 }

src/test/codegen-units/partitioning/local-inlining.rs

@@ -28,28 +28,28 @@ mod inline {
     }
 }
 
-mod user1 {
+pub mod user1 {
     use super::inline;
 
-    //~ TRANS_ITEM fn local_inlining::user1[0]::foo[0] @@ local_inlining-user1[Internal]
-    fn foo() {
+    //~ TRANS_ITEM fn local_inlining::user1[0]::foo[0] @@ local_inlining-user1[External]
+    pub fn foo() {
         inline::inlined_function();
     }
 }
 
-mod user2 {
+pub mod user2 {
     use super::inline;
 
-    //~ TRANS_ITEM fn local_inlining::user2[0]::bar[0] @@ local_inlining-user2[Internal]
-    fn bar() {
+    //~ TRANS_ITEM fn local_inlining::user2[0]::bar[0] @@ local_inlining-user2[External]
+    pub fn bar() {
         inline::inlined_function();
     }
 }
 
-mod non_user {
+pub mod non_user {
 
-    //~ TRANS_ITEM fn local_inlining::non_user[0]::baz[0] @@ local_inlining-non_user[Internal]
-    fn baz() {
+    //~ TRANS_ITEM fn local_inlining::non_user[0]::baz[0] @@ local_inlining-non_user[External]
+    pub fn baz() {
 
     }
 }

src/test/codegen-units/partitioning/local-transitive-inlining.rs

@@ -15,7 +15,7 @@
 // compile-flags:-Zinline-in-all-cgus
 
 #![allow(dead_code)]
-#![crate_type="lib"]
+#![crate_type="rlib"]
 
 mod inline {
 
@@ -37,19 +37,19 @@ mod direct_user {
     }
 }
 
-mod indirect_user {
+pub mod indirect_user {
     use super::direct_user;
 
-    //~ TRANS_ITEM fn local_transitive_inlining::indirect_user[0]::bar[0] @@ local_transitive_inlining-indirect_user[Internal]
-    fn bar() {
+    //~ TRANS_ITEM fn local_transitive_inlining::indirect_user[0]::bar[0] @@ local_transitive_inlining-indirect_user[External]
+    pub fn bar() {
         direct_user::foo();
     }
 }
 
-mod non_user {
+pub mod non_user {
 
-    //~ TRANS_ITEM fn local_transitive_inlining::non_user[0]::baz[0] @@ local_transitive_inlining-non_user[Internal]
-    fn baz() {
+    //~ TRANS_ITEM fn local_transitive_inlining::non_user[0]::baz[0] @@ local_transitive_inlining-non_user[External]
+    pub fn baz() {
 
     }
 }