cross crate polymorphization

compiler/rustc_codegen_ssa/src/back/symbol_export.rs

@@ -1,4 +1,5 @@
-use std::collections::hash_map::Entry::*;
+use std::collections::btree_map::Entry::*;
+use std::collections::BTreeMap;
 
 use rustc_ast::expand::allocator::ALLOCATOR_METHODS;
 use rustc_data_structures::fingerprint::Fingerprint;
@@ -14,7 +15,7 @@ use rustc_middle::middle::exported_symbols::{
 use rustc_middle::ty::query::{ExternProviders, Providers};
 use rustc_middle::ty::subst::{GenericArgKind, SubstsRef};
 use rustc_middle::ty::Instance;
-use rustc_middle::ty::{SymbolName, TyCtxt};
+use rustc_middle::ty::{self, SymbolName, TyCtxt};
 use rustc_session::config::CrateType;
 use rustc_target::spec::SanitizerSet;
 
@@ -272,10 +273,10 @@ fn exported_symbols_provider_local(
 fn upstream_monomorphizations_provider(
     tcx: TyCtxt<'_>,
     (): (),
-) -> DefIdMap<FxHashMap<SubstsRef<'_>, CrateNum>> {
+) -> DefIdMap<BTreeMap<SubstsRef<'_>, CrateNum>> {
     let cnums = tcx.crates(());
 
-    let mut instances: DefIdMap<FxHashMap<_, _>> = Default::default();
+    let mut instances: DefIdMap<BTreeMap<_, _>> = Default::default();
 
     let cnum_stable_ids: IndexVec<CrateNum, Fingerprint> = {
         let mut cnum_stable_ids = IndexVec::from_elem_n(Fingerprint::ZERO, cnums.len() + 1);
@@ -333,7 +334,7 @@ fn upstream_monomorphizations_provider(
 fn upstream_monomorphizations_for_provider(
     tcx: TyCtxt<'_>,
     def_id: DefId,
-) -> Option<&FxHashMap<SubstsRef<'_>, CrateNum>> {
+) -> Option<&BTreeMap<SubstsRef<'_>, CrateNum>> {
     debug_assert!(!def_id.is_local());
     tcx.upstream_monomorphizations(()).get(&def_id)
 }
@@ -343,7 +344,20 @@ fn upstream_drop_glue_for_provider<'tcx>(
     substs: SubstsRef<'tcx>,
 ) -> Option<CrateNum> {
     if let Some(def_id) = tcx.lang_items().drop_in_place_fn() {
-        tcx.upstream_monomorphizations_for(def_id).and_then(|monos| monos.get(&substs).cloned())
+        tcx.upstream_monomorphizations_for(def_id).and_then(|monos| {
+            monos.get(&substs).cloned().or_else(|| {
+                monos
+                    .iter()
+                    .find(|(k, _)| {
+                        tcx.is_polymorphic_parent((
+                            ty::InstanceDef::Item(ty::WithOptConstParam::unknown(def_id)),
+                            k,
+                            substs,
+                        ))
+                    })
+                    .map(|(_, &v)| v)
+            })
+        })
     } else {
         None
     }

compiler/rustc_middle/src/mir/mono.rs

@@ -288,7 +288,6 @@ impl MonoItemMap<'tcx> {
     ) -> Option<Instance<'tcx>> {
         if instance.substs.non_erasable_generics().next().is_some() {
             for substs in self.item_map.get(&instance.def).into_iter().flat_map(|v| v).copied() {
-                // FIXME(polymorphization): Deal with more complex polymorphized stuff.
                 if substs == instance.substs
                     || tcx.is_polymorphic_parent((instance.def, substs, instance.substs))
                 {

compiler/rustc_middle/src/query/mod.rs

@@ -1307,7 +1307,7 @@ rustc_queries! {
     /// added or removed in any upstream crate. Instead use the narrower
     /// `upstream_monomorphizations_for`, `upstream_drop_glue_for`, or, even
     /// better, `Instance::upstream_monomorphization()`.
-    query upstream_monomorphizations(_: ()) -> DefIdMap<FxHashMap<SubstsRef<'tcx>, CrateNum>> {
+    query upstream_monomorphizations(_: ()) -> DefIdMap<BTreeMap<SubstsRef<'tcx>, CrateNum>> {
         storage(ArenaCacheSelector<'tcx>)
         desc { "collecting available upstream monomorphizations" }
     }
@@ -1320,7 +1320,7 @@ rustc_queries! {
     /// You likely want to call `Instance::upstream_monomorphization()`
     /// instead of invoking this query directly.
     query upstream_monomorphizations_for(def_id: DefId)
-        -> Option<&'tcx FxHashMap<SubstsRef<'tcx>, CrateNum>> {
+        -> Option<&'tcx BTreeMap<SubstsRef<'tcx>, CrateNum>> {
             desc { |tcx|
                 "collecting available upstream monomorphizations for `{}`",
                 tcx.def_path_str(def_id),

compiler/rustc_middle/src/ty/instance.rs

@@ -127,11 +127,16 @@ impl<'tcx> Instance<'tcx> {
         self.substs.non_erasable_generics().next()?;
 
         match self.def {
-            // FIXME(polymorphization): Deal with this. Can't use
-            // `polymorphize` as that causes cycles.
-            InstanceDef::Item(def) => tcx
-                .upstream_monomorphizations_for(def.did)
-                .and_then(|monos| monos.get(&self.substs).cloned()),
+            InstanceDef::Item(def) => {
+                tcx.upstream_monomorphizations_for(def.did).and_then(|monos| {
+                    monos.get(&self.substs).cloned().or_else(|| {
+                        monos
+                            .iter()
+                            .find(|(k, _)| tcx.is_polymorphic_parent((self.def, k, self.substs)))
+                            .map(|(_, &v)| v)
+                    })
+                })
+            }
             InstanceDef::DropGlue(_, Some(_)) => tcx.upstream_drop_glue_for(self.substs),
             _ => None,
         }
@@ -594,7 +599,18 @@ impl<'tcx> Instance<'tcx> {
             // polymorphic instances from separate crates,
             // and assume that we just have a mono item for this
             // instance in some other crate.
-            None => self,
+            None => match self.def {
+                InstanceDef::Item(def) if !def.is_local() => tcx
+                    .upstream_monomorphizations_for(def.did)
+                    .and_then(|monos| {
+                        monos
+                            .iter()
+                            .find(|(k, _)| tcx.is_polymorphic_parent((self.def, k, self.substs)))
+                            .map(|(k, _)| Instance { def: self.def, substs: k })
+                    })
+                    .unwrap_or(self),
+                _ => self,
+            },
         }
     }
 }