IRGen: Force emission of lazy witness table when conformance descriptor is referenced
Otherwise with the new resilient witness table emission pattern, we might miss
conformances for refined protocols, since the witness table itself is never
referenced, only the conformance descriptor is.
Fixes <rdar://problem/46133018>.
diff --git a/lib/IRGen/GenDecl.cpp b/lib/IRGen/GenDecl.cpp
index 5feff4b..95a7a69 100644
--- a/lib/IRGen/GenDecl.cpp
+++ b/lib/IRGen/GenDecl.cpp
@@ -3539,6 +3539,8 @@
llvm::Constant *IRGenModule::getAddrOfProtocolConformanceDescriptor(
const RootProtocolConformance *conformance,
ConstantInit definition) {
+ IRGen.addLazyWitnessTable(conformance);
+
auto entity = LinkEntity::forProtocolConformanceDescriptor(conformance);
return getAddrOfLLVMVariable(entity, definition,
DebugTypeInfo());
diff --git a/test/IRGen/lazy_conformances.swift b/test/IRGen/lazy_conformances.swift
new file mode 100644
index 0000000..7f7889d
--- /dev/null
+++ b/test/IRGen/lazy_conformances.swift
@@ -0,0 +1,41 @@
+// RUN: %target-swift-frontend -parse-as-library -O %s -emit-ir | %FileCheck %s
+
+// CHECK: @"$s17lazy_conformances12MyCollectionVyxGSKAASKRzrlMc" = hidden constant {
+// CHECK: @"$s17lazy_conformances12MyCollectionVyxGSTAAMc" = hidden constant {
+
+struct MyCollection<Base : Collection> : Collection {
+ typealias Index = Base.Index
+ typealias Element = Base.Element
+
+ var startIndex: Index {
+ fatalError()
+ }
+
+ var endIndex: Index {
+ fatalError()
+ }
+
+ func index(after i: Index) -> Index {
+ fatalError()
+ }
+
+ func formIndex(after i: inout Index) {
+ fatalError()
+ }
+
+ subscript(position: Index) -> Element {
+ fatalError()
+ }
+}
+
+extension MyCollection : BidirectionalCollection
+ where Base : BidirectionalCollection
+{
+ func index(before i: Index) -> Index {
+ fatalError()
+ }
+
+ func formIndex(before i: inout Index) {
+ fatalError()
+ }
+}
