[cxx-interop] ensure destructors referenced only by the exception cle…

lib/IRGen/GenClangDecl.cpp

@@ -85,8 +85,19 @@ class ClangDeclFinder
   bool VisitCXXConstructorDecl(clang::CXXConstructorDecl *CXXCD) {
     callback(CXXCD);
     for (clang::CXXCtorInitializer *CXXCI : CXXCD->inits()) {
-      if (clang::FieldDecl *FD = CXXCI->getMember())
+      if (clang::FieldDecl *FD = CXXCI->getMember()) {
         callback(FD);
+        // A throwing constructor might throw after the field is initialized,
+        // emitting additional cleanup code that destroys the field. Make sure
+        // we record the destructor of the field in that case as it might need
+        // to be potentially emitted.
+        if (auto *recordType = FD->getType()->getAsCXXRecordDecl()) {
+          if (auto *destructor = recordType->getDestructor()) {
+            if (!destructor->isDeleted())
+              callback(destructor);
+          }
+        }
+      }
     }
     return true;
   }

test/Interop/Cxx/class/throwing-constructor-destructor-cleanup-ref-irgen.swift

@@ -0,0 +1,53 @@
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+// RUN: %target-swiftxx-frontend -emit-ir -I %t/Inputs -validate-tbd-against-ir=none %t/test.swift | %FileCheck %s
+
+//--- Inputs/module.modulemap
+module ThrowingConstructorDestructorCleanupRef {
+  header "test.h"
+  requires cplusplus
+}
+//--- Inputs/test.h
+
+void testFunc(int x);
+
+template<class T>
+class HasDestructor {
+    T x = 0;
+public:
+
+    HasDestructor() { }
+    HasDestructor(const HasDestructor &other) : x(other.x) {}
+    inline ~HasDestructor() { testFunc(42); }
+};
+
+template<class T>
+class HasThrowingConstructor {
+    HasDestructor<T> m;
+public:
+    HasThrowingConstructor();
+    ~HasThrowingConstructor();
+    inline HasThrowingConstructor(const HasThrowingConstructor &f) : m(f.m) {
+        doSomethingThatMightThrow();
+    }
+
+    void doSomethingThatMightThrow();
+};
+
+inline void test33(const HasThrowingConstructor<int> x) {
+
+}
+
+using HasThrowingConstructorInt = HasThrowingConstructor<int>;
+
+//--- test.swift
+
+import ThrowingConstructorDestructorCleanupRef
+
+public func test() {
+  let x = HasThrowingConstructorInt()
+  test33(x)
+}
+
+// Make sure we reach the destructor of 'HasDestructor'
+// CHECK: define linkonce_odr {{.*}} @{{_ZN13HasDestructorIiED2Ev|"\?\?1\?\$HasDestructor@H@@QEAA@XZ"}}