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Select upstream monomorphizations in a stable way.

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This commit is contained in:
Michael Woerister 2018-03-12 18:28:53 +01:00
parent 5316a458b2
commit 213ef111cf
1 changed files with 35 additions and 5 deletions
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40
src/librustc_trans/back/symbol_export.rs
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@ -14,8 +14,8 @@ use std::sync::Arc;
use monomorphize::Instance;
use rustc::hir;
use rustc::hir::TransFnAttrFlags;
use rustc::hir::def_id::CrateNum;
use rustc::hir::def_id::{DefId, LOCAL_CRATE};
use rustc::hir::def_id::{CrateNum, DefId, LOCAL_CRATE, CRATE_DEF_INDEX};
use rustc::ich::Fingerprint;
use rustc::middle::exported_symbols::{SymbolExportLevel, ExportedSymbol, metadata_symbol_name};
use rustc::session::config;
use rustc::ty::{TyCtxt, SymbolName};
@ -23,6 +23,9 @@ use rustc::ty::maps::Providers;
use rustc::ty::subst::Substs;
use rustc::util::nodemap::{FxHashMap, DefIdMap};
use rustc_allocator::ALLOCATOR_METHODS;
use rustc_data_structures::indexed_vec::IndexVec;
use syntax::attr;
use std::collections::hash_map::Entry::*;
pub type ExportedSymbols = FxHashMap<
CrateNum,
@ -282,12 +285,39 @@ fn upstream_monomorphizations_provider<'a, 'tcx>(
let mut instances = DefIdMap();
let cnum_stable_ids: IndexVec<CrateNum, Fingerprint> = {
let mut cnum_stable_ids = IndexVec::from_elem_n(Fingerprint::ZERO,
cnums.len() + 1);
for &cnum in cnums.iter() {
cnum_stable_ids[cnum] = tcx.def_path_hash(DefId {
krate: cnum,
index: CRATE_DEF_INDEX,
}).0;
}
cnum_stable_ids
};
for &cnum in cnums.iter() {
for &(ref exported_symbol, _) in tcx.exported_symbols(cnum).iter() {
if let &ExportedSymbol::Generic(def_id, substs) = exported_symbol {
instances.entry(def_id)
.or_insert_with(|| FxHashMap())
.insert(substs, cnum);
let substs_map = instances.entry(def_id)
.or_insert_with(|| FxHashMap());
match substs_map.entry(substs) {
Occupied(mut e) => {
// If there are multiple monomorphizations available,
// we select one deterministically.
let other_cnum = *e.get();
if cnum_stable_ids[other_cnum] > cnum_stable_ids[cnum] {
e.insert(cnum);
}
}
Vacant(e) => {
e.insert(cnum);
}
}
}
}
}