Fix initialization of imported ObjC block types.

lib/SIL/IR/ValueOwnership.cpp

@@ -652,9 +652,22 @@ UNOWNED_OR_NONE_DEPENDING_ON_RESULT(AtomicLoad)
 UNOWNED_OR_NONE_DEPENDING_ON_RESULT(ExtractElement)
 UNOWNED_OR_NONE_DEPENDING_ON_RESULT(InsertElement)
 UNOWNED_OR_NONE_DEPENDING_ON_RESULT(ShuffleVector)
-UNOWNED_OR_NONE_DEPENDING_ON_RESULT(ZeroInitializer)
 #undef UNOWNED_OR_NONE_DEPENDING_ON_RESULT
 
+#define OWNED_OR_NONE_DEPENDING_ON_RESULT(ID)                                  \
+  ValueOwnershipKind ValueOwnershipKindBuiltinVisitor::visit##ID(              \
+      BuiltinInst *BI, StringRef Attr) {                                       \
+    if (BI->getType().isTrivial(*BI->getFunction())) {                         \
+      return OwnershipKind::None;                                              \
+    }                                                                          \
+    return OwnershipKind::Owned;                                               \
+  }
+// A zeroInitializer may initialize an imported struct with __unsafe_unretained
+// fields. The initialized value is immediately consumed by an assignment, so it
+// must be owned.
+OWNED_OR_NONE_DEPENDING_ON_RESULT(ZeroInitializer)
+#undef OWNED_OR_NONE_DEPENDING_ON_RESULT
+
 #define BUILTIN(X,Y,Z)
 #define BUILTIN_SIL_OPERATION(ID, NAME, CATEGORY) \
   ValueOwnershipKind ValueOwnershipKindBuiltinVisitor::visit##ID( \

test/ClangImporter/Inputs/objc_init_blocks.h

@@ -0,0 +1,7 @@
+#import <CoreFoundation/CoreFoundation.h>
+
+typedef bool (^boolBlock)(void);
+
+struct objc_bool_block {
+  __unsafe_unretained boolBlock block;
+};

test/ClangImporter/objc_init_blocks.swift

@@ -0,0 +1,18 @@
+// RUN: %target-swift-frontend -import-objc-header %S/Inputs/objc_init_blocks.h %s -emit-sil -sil-verify-all
+
+// REQUIRES: objc_interop
+
+// rdar://126142109: import an __unsafe_unretained block as zero-initialized.
+//
+// Make sure that the SIL ownership verifier passes.
+// UnsafeUnretainedBlockClass.init()
+// CHECK-LABEL: sil hidden @$s16objc_init_blocks26UnsafeUnretainedBlockClassCACycfc : $@convention(method) (@owned UnsafeUnretainedBlockClass) -> @owned UnsafeUnretainedBlockClass {
+// CHECK: [[ZI:%.*]] = builtin "zeroInitializer"<objc_bool_block>() : $objc_bool_block
+// CHECK:   store [[ZI]] to %{{.*}} : $*objc_bool_block
+// CHECK-LABEL: } // end sil function '$s16objc_init_blocks26UnsafeUnretainedBlockClassCACycfc'
+open class UnsafeUnretainedBlockClass {
+  public internal(set) var sc: objc_bool_block
+  init() {
+    self.sc = objc_bool_block()
+  }
+}