From 1bc329af144f602e655e0430d1ec973aedb7d7a6 Mon Sep 17 00:00:00 2001
From: Nicholas Bishop <nicholasbishop@google.com>
Date: Mon, 4 May 2026 16:28:58 -0400
Subject: [PATCH] Support calling Carbon destructors from C++ (#7143)

A destructor is added to the C++ class definition in
`CarbonExternalASTSource::CompleteType`. The destructor calls a Carbon
function that calls the `Destroy` operator.
---
 toolchain/check/cpp/export.cpp                |  72 +++-
 toolchain/check/cpp/export.h                  |   7 +
 toolchain/check/cpp/generate_ast.cpp          |   2 +
 toolchain/check/thunk.cpp                     |  35 ++
 toolchain/check/thunk.h                       |   4 +
 .../testdata/interop/cpp/reverse/class.carbon | 308 ++++++++++++++----
 .../interop/cpp/reverse/method.carbon         | 202 +++++++++---
 7 files changed, 498 insertions(+), 132 deletions(-)

diff --git a/toolchain/check/cpp/export.cpp b/toolchain/check/cpp/export.cpp
index e0fdec4e3a66..87dc23085f66 100644
--- a/toolchain/check/cpp/export.cpp
+++ b/toolchain/check/cpp/export.cpp
@@ -555,6 +555,20 @@ static auto BuildCppToCarbonThunkDecl(
   return thunk_function_decl;
 }
 
+// Get an expr for accessing `this` in a method.
+static auto GetThisArg(clang::Sema& sema, clang::SourceLocation clang_loc,
+                       clang::CXXRecordDecl* record_decl) -> clang::Expr* {
+  clang::QualType class_type =
+      sema.getASTContext().getCanonicalTagType(record_decl);
+  auto class_ptr_type = sema.getASTContext().getPointerType(class_type);
+  auto* this_expr = sema.BuildCXXThisExpr(clang_loc, class_ptr_type,
+                                          /*IsImplicit=*/true);
+  return clang::UnaryOperator::Create(
+      sema.getASTContext(), this_expr, clang::UO_Deref, class_type,
+      clang::ExprValueKind::VK_LValue, clang::ExprObjectKind::OK_Ordinary,
+      clang_loc, /*CanOverflow=*/false, clang::FPOptionsOverride());
+}
+
 // Create the body of a C++ thunk that calls a Carbon thunk. The
 // arguments are passed by reference to the callee.
 static auto BuildCppToCarbonThunkBody(clang::Sema& sema,
@@ -599,16 +613,7 @@ static auto BuildCppToCarbonThunkBody(clang::Sema& sema,
   // For methods, pass the `this` pointer as the first argument to the callee.
   if (target.self_param) {
     auto* parent_class = cast<clang::CXXRecordDecl>(target.decl_context);
-    clang::QualType class_type =
-        sema.getASTContext().getCanonicalTagType(parent_class);
-    auto class_ptr_type = sema.getASTContext().getPointerType(class_type);
-    auto* this_expr = sema.BuildCXXThisExpr(clang_loc, class_ptr_type,
-                                            /*IsImplicit=*/true);
-    this_expr = clang::UnaryOperator::Create(
-        sema.getASTContext(), this_expr, clang::UO_Deref, class_type,
-        clang::ExprValueKind::VK_LValue, clang::ExprObjectKind::OK_Ordinary,
-        clang_loc, /*CanOverflow=*/false, clang::FPOptionsOverride());
-    call_args.push_back(this_expr);
+    call_args.push_back(GetThisArg(sema, clang_loc, parent_class));
   }
   for (auto* param : function_decl->parameters()) {
     clang::Expr* call_arg =
@@ -765,4 +770,51 @@ auto ExportFunctionToCpp(Context& context, SemIR::LocId loc_id,
                                carbon_function_decl);
 }
 
+auto ExportDestructorToCpp(Context& context, const SemIR::Class& class_info,
+                           clang::CXXRecordDecl* record_decl)
+    -> clang::CXXDestructorDecl* {
+  SemIR::LocId loc_id(class_info.first_decl_id());
+  auto clang_loc = record_decl->getLocation();
+
+  // Create C++ destructor decl.
+  auto class_type = context.ast_context().getCanonicalTagType(record_decl);
+  auto name =
+      context.ast_context().DeclarationNames.getCXXDestructorName(class_type);
+  clang::DeclarationNameInfo name_info(name, clang_loc);
+  clang::QualType type = context.ast_context().getFunctionType(
+      context.ast_context().VoidTy, llvm::ArrayRef<clang::QualType>(),
+      clang::FunctionProtoType::ExtProtoInfo());
+  auto* cpp_destructor_decl = clang::CXXDestructorDecl::Create(
+      context.ast_context(), record_decl,
+      /*StartLoc=*/clang_loc, name_info, type, /*TInfo=*/nullptr,
+      /*UsesFPIntrin=*/false, /*isInline=*/true, /*isImplicitlyDeclared=*/true,
+      clang::ConstexprSpecKind::Unspecified);
+  cpp_destructor_decl->setAccess(clang::AS_public);
+
+  // Create Carbon thunk that destroys the object, and get a C++
+  // function decl for calling it.
+  auto thunk_function_id = BuildDestroyThunk(context, loc_id, class_info);
+  auto* cpp_function_decl =
+      BuildCppFunctionDeclForCarbonFn(context, loc_id, thunk_function_id);
+
+  clang::Sema& sema = context.clang_sema();
+
+  // Build the destructor body.
+  clang::Sema::ContextRAII context_raii(sema, cpp_destructor_decl);
+  sema.ActOnStartOfFunctionDef(nullptr, cpp_destructor_decl);
+
+  // Create a clang call expr to call the Carbon thunk.
+  clang::ExprResult callee =
+      sema.BuildDeclRefExpr(cpp_function_decl, cpp_function_decl->getType(),
+                            clang::VK_PRValue, clang_loc);
+  llvm::SmallVector<clang::Expr*> call_args;
+  call_args.push_back(GetThisArg(sema, clang_loc, record_decl));
+  clang::ExprResult call = sema.BuildCallExpr(nullptr, callee.get(), clang_loc,
+                                              call_args, clang_loc);
+
+  sema.ActOnFinishFunctionBody(cpp_destructor_decl, call.get());
+
+  return cpp_destructor_decl;
+}
+
 }  // namespace Carbon::Check
diff --git a/toolchain/check/cpp/export.h b/toolchain/check/cpp/export.h
index ae690661c802..cb29a4745960 100644
--- a/toolchain/check/cpp/export.h
+++ b/toolchain/check/cpp/export.h
@@ -58,6 +58,13 @@ auto CalculateCppFieldOffsets(
 auto ExportFunctionToCpp(Context& context, SemIR::LocId loc_id,
                          SemIR::FunctionId function_id) -> clang::FunctionDecl*;
 
+// Export a Carbon destructor into C++.
+//
+// The destructor calls the `Destroy` operator.
+auto ExportDestructorToCpp(Context& context, const SemIR::Class& class_info,
+                           clang::CXXRecordDecl* record_decl)
+    -> clang::CXXDestructorDecl*;
+
 }  // namespace Carbon::Check
 
 #endif  // CARBON_TOOLCHAIN_CHECK_CPP_EXPORT_H_
diff --git a/toolchain/check/cpp/generate_ast.cpp b/toolchain/check/cpp/generate_ast.cpp
index 43b2c29ba475..12c17734f692 100644
--- a/toolchain/check/cpp/generate_ast.cpp
+++ b/toolchain/check/cpp/generate_ast.cpp
@@ -641,6 +641,8 @@ auto CarbonExternalASTSource::CompleteType(clang::TagDecl* tag_decl) -> void {
 
   ExportAllFieldsToCpp(*context_, class_info);
 
+  class_decl->addDecl(ExportDestructorToCpp(*context_, class_info, class_decl));
+
   // TODO: Import any special member functions that affect class properties.
   class_decl->completeDefinition();
 }
diff --git a/toolchain/check/thunk.cpp b/toolchain/check/thunk.cpp
index 46dcce5dd610..2eaf74e0fdef 100644
--- a/toolchain/check/thunk.cpp
+++ b/toolchain/check/thunk.cpp
@@ -17,6 +17,7 @@
 #include "toolchain/check/inst.h"
 #include "toolchain/check/member_access.h"
 #include "toolchain/check/name_ref.h"
+#include "toolchain/check/operator.h"
 #include "toolchain/check/pattern.h"
 #include "toolchain/check/pattern_match.h"
 #include "toolchain/check/pointer_dereference.h"
@@ -515,4 +516,38 @@ auto BuildThunk(Context& context, SemIR::FunctionId signature_id,
   return thunk_id;
 }
 
+auto BuildDestroyThunk(Context& context, SemIR::LocId loc_id,
+                       const SemIR::Class& class_info) -> SemIR::FunctionId {
+  // Create a new function declaration.
+  auto thunk_name_id = SemIR::NameId::ForIdentifier(
+      context.identifiers().Add("__destroy_thunk"));
+  auto [thunk_inst_id, thunk_function_id] =
+      MakeGeneratedFunctionDecl(context, loc_id,
+                                {.parent_scope_id = class_info.scope_id,
+                                 .name_id = thunk_name_id,
+                                 .self_type_id = class_info.self_type_id});
+
+  auto& thunk_function = context.functions().Get(thunk_function_id);
+  thunk_function.SetThunk(SemIR::InstId::None);
+
+  context.scope_stack().PushForDeclName();
+  StartFunctionDefinition(context, thunk_inst_id, thunk_function_id);
+
+  // Get `self` arg.
+  auto params = context.inst_blocks().Get(thunk_function.call_params_id);
+  auto self_inst_id = params[0];
+
+  // Build the function body. This calls the `Destroy` operator on `self`.
+  auto destroy_inst_id = BuildUnaryOperator(
+      context, loc_id, {.interface_name = CoreIdentifier::Destroy},
+      self_inst_id);
+  DiscardExpr(context, destroy_inst_id);
+  BuildReturnWithNoExpr(context, loc_id);
+
+  FinishFunctionDefinition(context, thunk_function_id);
+  context.scope_stack().Pop();
+
+  return thunk_function_id;
+}
+
 }  // namespace Carbon::Check
diff --git a/toolchain/check/thunk.h b/toolchain/check/thunk.h
index e1589987b545..9805e901dc70 100644
--- a/toolchain/check/thunk.h
+++ b/toolchain/check/thunk.h
@@ -46,6 +46,10 @@ auto BuildThunkDefinitionForExport(Context& context,
                                    SemIR::InstId thunk_id,
                                    SemIR::InstId callee_id) -> void;
 
+// Build a function that destroys an object of the given class.
+auto BuildDestroyThunk(Context& context, SemIR::LocId loc_id,
+                       const SemIR::Class& class_info) -> SemIR::FunctionId;
+
 }  // namespace Carbon::Check
 
 #endif  // CARBON_TOOLCHAIN_CHECK_THUNK_H_
diff --git a/toolchain/lower/testdata/interop/cpp/reverse/class.carbon b/toolchain/lower/testdata/interop/cpp/reverse/class.carbon
index 719a20274299..790523600207 100644
--- a/toolchain/lower/testdata/interop/cpp/reverse/class.carbon
+++ b/toolchain/lower/testdata/interop/cpp/reverse/class.carbon
@@ -3,6 +3,7 @@
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 // INCLUDE-FILE: toolchain/testing/testdata/min_prelude/int.carbon
+// EXTRA-ARGS: --clang-arg=-fno-exceptions
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
@@ -156,13 +157,20 @@ fn G() {
 // CHECK:STDOUT: %"class.Carbon::B" = type { %"class.Carbon::A", i32 }
 // CHECK:STDOUT: %"class.Carbon::C" = type { %"class.Carbon::A", i32 }
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: mustprogress uwtable
+// CHECK:STDOUT: $_ZN6Carbon1AD2Ev = comdat any
+// CHECK:STDOUT:
+// CHECK:STDOUT: $_ZN6Carbon1BD2Ev = comdat any
+// CHECK:STDOUT:
+// CHECK:STDOUT: $_ZN6Carbon1CD2Ev = comdat any
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: mustprogress nounwind uwtable
 // CHECK:STDOUT: define dso_local void @_Z1fv() #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %a = alloca %"class.Carbon::A", align 8
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %a) #3
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %a) #5
 // CHECK:STDOUT:   call void @_ZN6CarbonL5CallAEPNS_1AE(ptr noundef %a)
-// CHECK:STDOUT:   call void @llvm.lifetime.end.p0(ptr %a) #3
+// CHECK:STDOUT:   call void @_ZN6Carbon1AD2Ev(ptr noundef nonnull align 8 dead_on_return(12) dereferenceable(12) %a)
+// CHECK:STDOUT:   call void @llvm.lifetime.end.p0(ptr %a) #5
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -178,16 +186,27 @@ fn G() {
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: inlinehint mustprogress nounwind uwtable
+// CHECK:STDOUT: define linkonce_odr dso_local void @_ZN6Carbon1AD2Ev(ptr noundef nonnull align 8 dead_on_return(12) dereferenceable(12) %this) unnamed_addr #3 comdat align 2 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %this.addr = alloca ptr, align 8
+// CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !11
+// CHECK:STDOUT:   %this1 = load ptr, ptr %this.addr, align 8
+// CHECK:STDOUT:   call void @"_C__destroy_thunk:thunk.A.Main"(ptr noundef nonnull align 8 dereferenceable(12) %this1)
+// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
 // CHECK:STDOUT: declare void @llvm.lifetime.end.p0(ptr captures(none)) #1
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: mustprogress uwtable
+// CHECK:STDOUT: ; Function Attrs: mustprogress nounwind uwtable
 // CHECK:STDOUT: define dso_local void @_Z1gv() #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %b = alloca %"class.Carbon::B", align 8
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %b) #3
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %b) #5
 // CHECK:STDOUT:   call void @_ZN6CarbonL5CallBEPNS_1BE(ptr noundef %b)
-// CHECK:STDOUT:   call void @llvm.lifetime.end.p0(ptr %b) #3
+// CHECK:STDOUT:   call void @_ZN6Carbon1BD2Ev(ptr noundef nonnull align 8 dead_on_return(16) dereferenceable(16) %b)
+// CHECK:STDOUT:   call void @llvm.lifetime.end.p0(ptr %b) #5
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -200,14 +219,27 @@ fn G() {
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: mustprogress uwtable
+// CHECK:STDOUT: ; Function Attrs: inlinehint mustprogress nounwind uwtable
+// CHECK:STDOUT: define linkonce_odr dso_local void @_ZN6Carbon1BD2Ev(ptr noundef nonnull align 8 dead_on_return(16) dereferenceable(16) %this) unnamed_addr #3 comdat align 2 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %this.addr = alloca ptr, align 8
+// CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !14
+// CHECK:STDOUT:   %this1 = load ptr, ptr %this.addr, align 8
+// CHECK:STDOUT:   call void @"_C__destroy_thunk:thunk.B.Main"(ptr noundef nonnull align 8 dereferenceable(16) %this1)
+// CHECK:STDOUT:   %a = getelementptr inbounds nuw %"class.Carbon::B", ptr %this1, i32 0, i32 0
+// CHECK:STDOUT:   call void @_ZN6Carbon1AD2Ev(ptr noundef nonnull align 8 dead_on_return(12) dereferenceable(12) %a)
+// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: mustprogress nounwind uwtable
 // CHECK:STDOUT: define dso_local void @_Z1hv() #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %c = alloca %"class.Carbon::C", align 8
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %c) #3
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %c) #5
 // CHECK:STDOUT:   call void @_ZN6CarbonL5CallCEPNS_1CE(ptr noundef %c)
 // CHECK:STDOUT:   call void @_ZN6CarbonL5CallAEPNS_1AE(ptr noundef %c)
-// CHECK:STDOUT:   call void @llvm.lifetime.end.p0(ptr %c) #3
+// CHECK:STDOUT:   call void @_ZN6Carbon1CD2Ev(ptr noundef nonnull align 8 dead_on_return(16) dereferenceable(16) %c)
+// CHECK:STDOUT:   call void @llvm.lifetime.end.p0(ptr %c) #5
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -220,40 +252,119 @@ fn G() {
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: inlinehint mustprogress nounwind uwtable
+// CHECK:STDOUT: define linkonce_odr dso_local void @_ZN6Carbon1CD2Ev(ptr noundef nonnull align 8 dead_on_return(16) dereferenceable(16) %this) unnamed_addr #3 comdat align 2 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %this.addr = alloca ptr, align 8
+// CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !16
+// CHECK:STDOUT:   %this1 = load ptr, ptr %this.addr, align 8
+// CHECK:STDOUT:   call void @"_C__destroy_thunk:thunk.C.Main"(ptr noundef nonnull align 8 dereferenceable(16) %this1)
+// CHECK:STDOUT:   call void @_ZN6Carbon1AD2Ev(ptr noundef nonnull align 8 dead_on_return(12) dereferenceable(12) %this1)
+// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: declare void @_CCallA.Main(ptr)
 // CHECK:STDOUT:
 // CHECK:STDOUT: declare void @_CCallB.Main(ptr)
 // CHECK:STDOUT:
 // CHECK:STDOUT: declare void @_CCallC.Main(ptr)
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CCallA__carbon_thunk.Main(ptr %_) #3 !dbg !18 {
+// CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
+// CHECK:STDOUT: define void @"_C__destroy_thunk:thunk.A.Main"(ptr %self) #4 !dbg !18 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc21 = load ptr, ptr %_, align 8, !dbg !24
-// CHECK:STDOUT:   call void @_CCallA.Main(ptr %.loc21), !dbg !24
+// CHECK:STDOUT:   call void @"_COp.1afa5e4ee26f3f8f:core.Destroy.Core"(ptr %self), !dbg !24
 // CHECK:STDOUT:   ret void, !dbg !24
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CCallB__carbon_thunk.Main(ptr %_) #3 !dbg !25 {
+// CHECK:STDOUT: define weak_odr void @"_COp.7e389eab4a7e5487:core.Destroy.Core"(ptr %self) #5 !dbg !25 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc22 = load ptr, ptr %_, align 8, !dbg !28
-// CHECK:STDOUT:   call void @_CCallB.Main(ptr %.loc22), !dbg !28
-// CHECK:STDOUT:   ret void, !dbg !28
+// CHECK:STDOUT:   ret void, !dbg !31
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CCallC__carbon_thunk.Main(ptr %_) #3 !dbg !29 {
+// CHECK:STDOUT: define weak_odr void @"_COp.ce21b459230035a4:core.Destroy.Core"(ptr %self) #5 !dbg !32 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc23 = load ptr, ptr %_, align 8, !dbg !32
-// CHECK:STDOUT:   call void @_CCallC.Main(ptr %.loc23), !dbg !32
-// CHECK:STDOUT:   ret void, !dbg !32
+// CHECK:STDOUT:   ret void, !dbg !35
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define weak_odr void @"_COp.1afa5e4ee26f3f8f:core.Destroy.Core"(ptr %self) #5 !dbg !36 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   ret void, !dbg !39
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CCallA__carbon_thunk.Main(ptr %_) #5 !dbg !40 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.loc21 = load ptr, ptr %_, align 8, !dbg !43
+// CHECK:STDOUT:   call void @_CCallA.Main(ptr %.loc21), !dbg !43
+// CHECK:STDOUT:   ret void, !dbg !43
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
+// CHECK:STDOUT: define void @"_C__destroy_thunk:thunk.B.Main"(ptr %self) #4 !dbg !44 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @"_COp.301c2cde953858ec:core.Destroy.Core"(ptr %self), !dbg !47
+// CHECK:STDOUT:   ret void, !dbg !47
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define weak_odr void @"_COp.1a8ac7d7e1ca560e:core.Destroy.Core"(ptr %self) #5 !dbg !48 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   ret void, !dbg !51
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define weak_odr void @"_COp.301c2cde953858ec:core.Destroy.Core"(ptr %self) #5 !dbg !52 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   ret void, !dbg !55
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CCallB__carbon_thunk.Main(ptr %_) #5 !dbg !56 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.loc22 = load ptr, ptr %_, align 8, !dbg !59
+// CHECK:STDOUT:   call void @_CCallB.Main(ptr %.loc22), !dbg !59
+// CHECK:STDOUT:   ret void, !dbg !59
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
+// CHECK:STDOUT: define void @"_C__destroy_thunk:thunk.C.Main"(ptr %self) #4 !dbg !60 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @"_COp.71e25083d63c4d6c:core.Destroy.Core"(ptr %self), !dbg !63
+// CHECK:STDOUT:   ret void, !dbg !63
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define weak_odr void @"_COp.e9c7e36fd2e174ea:core.Destroy.Core"(ptr %self) #5 !dbg !64 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   ret void, !dbg !67
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define weak_odr void @"_COp.71e25083d63c4d6c:core.Destroy.Core"(ptr %self) #5 !dbg !68 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   ret void, !dbg !71
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CCallC__carbon_thunk.Main(ptr %_) #5 !dbg !72 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.loc23 = load ptr, ptr %_, align 8, !dbg !75
+// CHECK:STDOUT:   call void @_CCallC.Main(ptr %.loc23), !dbg !75
+// CHECK:STDOUT:   ret void, !dbg !75
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; uselistorder directives
+// CHECK:STDOUT: uselistorder ptr @_ZN6Carbon1AD2Ev, { 2, 1, 0 }
+// CHECK:STDOUT:
+// CHECK:STDOUT: attributes #0 = { mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
 // CHECK:STDOUT: attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT: attributes #2 = { alwaysinline mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #3 = { nounwind }
+// CHECK:STDOUT: attributes #3 = { inlinehint mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #4 = { alwaysinline nounwind }
+// CHECK:STDOUT: attributes #5 = { nounwind }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!5}
@@ -277,21 +388,64 @@ fn G() {
 // CHECK:STDOUT: !15 = !{!"p1 _ZTSN6Carbon1BE", !13, i64 0}
 // CHECK:STDOUT: !16 = !{!17, !17, i64 0}
 // CHECK:STDOUT: !17 = !{!"p1 _ZTSN6Carbon1CE", !13, i64 0}
-// CHECK:STDOUT: !18 = distinct !DISubprogram(name: "CallA__carbon_thunk", linkageName: "_CCallA__carbon_thunk.Main", scope: null, file: !6, line: 21, type: !19, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !22)
+// CHECK:STDOUT: !18 = distinct !DISubprogram(name: "__destroy_thunk", linkageName: "_C__destroy_thunk:thunk.A.Main", scope: null, file: !6, line: 6, type: !19, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !22)
 // CHECK:STDOUT: !19 = !DISubroutineType(types: !20)
 // CHECK:STDOUT: !20 = !{null, !21}
 // CHECK:STDOUT: !21 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 64)
 // CHECK:STDOUT: !22 = !{!23}
 // CHECK:STDOUT: !23 = !DILocalVariable(arg: 1, scope: !18, type: !21)
-// CHECK:STDOUT: !24 = !DILocation(line: 21, column: 1, scope: !18)
-// CHECK:STDOUT: !25 = distinct !DISubprogram(name: "CallB__carbon_thunk", linkageName: "_CCallB__carbon_thunk.Main", scope: null, file: !6, line: 22, type: !19, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !26)
-// CHECK:STDOUT: !26 = !{!27}
-// CHECK:STDOUT: !27 = !DILocalVariable(arg: 1, scope: !25, type: !21)
-// CHECK:STDOUT: !28 = !DILocation(line: 22, column: 1, scope: !25)
-// CHECK:STDOUT: !29 = distinct !DISubprogram(name: "CallC__carbon_thunk", linkageName: "_CCallC__carbon_thunk.Main", scope: null, file: !6, line: 23, type: !19, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !30)
-// CHECK:STDOUT: !30 = !{!31}
-// CHECK:STDOUT: !31 = !DILocalVariable(arg: 1, scope: !29, type: !21)
-// CHECK:STDOUT: !32 = !DILocation(line: 23, column: 1, scope: !29)
+// CHECK:STDOUT: !24 = !DILocation(line: 6, column: 1, scope: !18)
+// CHECK:STDOUT: !25 = distinct !DISubprogram(name: "Op", linkageName: "_COp.7e389eab4a7e5487:core.Destroy.Core", scope: null, file: !6, line: 6, type: !26, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !29)
+// CHECK:STDOUT: !26 = !DISubroutineType(types: !27)
+// CHECK:STDOUT: !27 = !{null, !28}
+// CHECK:STDOUT: !28 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+// CHECK:STDOUT: !29 = !{!30}
+// CHECK:STDOUT: !30 = !DILocalVariable(arg: 1, scope: !25, type: !28)
+// CHECK:STDOUT: !31 = !DILocation(line: 6, column: 1, scope: !25)
+// CHECK:STDOUT: !32 = distinct !DISubprogram(name: "Op", linkageName: "_COp.ce21b459230035a4:core.Destroy.Core", scope: null, file: !6, line: 6, type: !19, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !33)
+// CHECK:STDOUT: !33 = !{!34}
+// CHECK:STDOUT: !34 = !DILocalVariable(arg: 1, scope: !32, type: !21)
+// CHECK:STDOUT: !35 = !DILocation(line: 6, column: 1, scope: !32)
+// CHECK:STDOUT: !36 = distinct !DISubprogram(name: "Op", linkageName: "_COp.1afa5e4ee26f3f8f:core.Destroy.Core", scope: null, file: !6, line: 6, type: !19, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !37)
+// CHECK:STDOUT: !37 = !{!38}
+// CHECK:STDOUT: !38 = !DILocalVariable(arg: 1, scope: !36, type: !21)
+// CHECK:STDOUT: !39 = !DILocation(line: 6, column: 1, scope: !36)
+// CHECK:STDOUT: !40 = distinct !DISubprogram(name: "CallA__carbon_thunk", linkageName: "_CCallA__carbon_thunk.Main", scope: null, file: !6, line: 21, type: !19, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !41)
+// CHECK:STDOUT: !41 = !{!42}
+// CHECK:STDOUT: !42 = !DILocalVariable(arg: 1, scope: !40, type: !21)
+// CHECK:STDOUT: !43 = !DILocation(line: 21, column: 1, scope: !40)
+// CHECK:STDOUT: !44 = distinct !DISubprogram(name: "__destroy_thunk", linkageName: "_C__destroy_thunk:thunk.B.Main", scope: null, file: !6, line: 11, type: !19, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !45)
+// CHECK:STDOUT: !45 = !{!46}
+// CHECK:STDOUT: !46 = !DILocalVariable(arg: 1, scope: !44, type: !21)
+// CHECK:STDOUT: !47 = !DILocation(line: 11, column: 1, scope: !44)
+// CHECK:STDOUT: !48 = distinct !DISubprogram(name: "Op", linkageName: "_COp.1a8ac7d7e1ca560e:core.Destroy.Core", scope: null, file: !6, line: 11, type: !19, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !49)
+// CHECK:STDOUT: !49 = !{!50}
+// CHECK:STDOUT: !50 = !DILocalVariable(arg: 1, scope: !48, type: !21)
+// CHECK:STDOUT: !51 = !DILocation(line: 11, column: 1, scope: !48)
+// CHECK:STDOUT: !52 = distinct !DISubprogram(name: "Op", linkageName: "_COp.301c2cde953858ec:core.Destroy.Core", scope: null, file: !6, line: 11, type: !19, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !53)
+// CHECK:STDOUT: !53 = !{!54}
+// CHECK:STDOUT: !54 = !DILocalVariable(arg: 1, scope: !52, type: !21)
+// CHECK:STDOUT: !55 = !DILocation(line: 11, column: 1, scope: !52)
+// CHECK:STDOUT: !56 = distinct !DISubprogram(name: "CallB__carbon_thunk", linkageName: "_CCallB__carbon_thunk.Main", scope: null, file: !6, line: 22, type: !19, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !57)
+// CHECK:STDOUT: !57 = !{!58}
+// CHECK:STDOUT: !58 = !DILocalVariable(arg: 1, scope: !56, type: !21)
+// CHECK:STDOUT: !59 = !DILocation(line: 22, column: 1, scope: !56)
+// CHECK:STDOUT: !60 = distinct !DISubprogram(name: "__destroy_thunk", linkageName: "_C__destroy_thunk:thunk.C.Main", scope: null, file: !6, line: 16, type: !19, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !61)
+// CHECK:STDOUT: !61 = !{!62}
+// CHECK:STDOUT: !62 = !DILocalVariable(arg: 1, scope: !60, type: !21)
+// CHECK:STDOUT: !63 = !DILocation(line: 16, column: 1, scope: !60)
+// CHECK:STDOUT: !64 = distinct !DISubprogram(name: "Op", linkageName: "_COp.e9c7e36fd2e174ea:core.Destroy.Core", scope: null, file: !6, line: 16, type: !19, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !65)
+// CHECK:STDOUT: !65 = !{!66}
+// CHECK:STDOUT: !66 = !DILocalVariable(arg: 1, scope: !64, type: !21)
+// CHECK:STDOUT: !67 = !DILocation(line: 16, column: 1, scope: !64)
+// CHECK:STDOUT: !68 = distinct !DISubprogram(name: "Op", linkageName: "_COp.71e25083d63c4d6c:core.Destroy.Core", scope: null, file: !6, line: 16, type: !19, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !69)
+// CHECK:STDOUT: !69 = !{!70}
+// CHECK:STDOUT: !70 = !DILocalVariable(arg: 1, scope: !68, type: !21)
+// CHECK:STDOUT: !71 = !DILocation(line: 16, column: 1, scope: !68)
+// CHECK:STDOUT: !72 = distinct !DISubprogram(name: "CallC__carbon_thunk", linkageName: "_CCallC__carbon_thunk.Main", scope: null, file: !6, line: 23, type: !19, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !73)
+// CHECK:STDOUT: !73 = !{!74}
+// CHECK:STDOUT: !74 = !DILocalVariable(arg: 1, scope: !72, type: !21)
+// CHECK:STDOUT: !75 = !DILocation(line: 23, column: 1, scope: !72)
 // CHECK:STDOUT: ; ModuleID = 'field.carbon'
 // CHECK:STDOUT: source_filename = "field.carbon"
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
@@ -315,47 +469,55 @@ fn G() {
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CG.Main() #1 !dbg !19 {
+// CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
+// CHECK:STDOUT: define void @"_C__destroy_thunk:thunk.C.Main"(ptr %self) #1 !dbg !19 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %c.var = alloca { i32, i32 }, align 8, !dbg !22
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %c.var), !dbg !22
-// CHECK:STDOUT:   %.loc19_29.3.a = getelementptr inbounds nuw { i32, i32 }, ptr %c.var, i32 0, i32 0, !dbg !23
-// CHECK:STDOUT:   %.loc19_29.6.b = getelementptr inbounds nuw { i32, i32 }, ptr %c.var, i32 0, i32 1, !dbg !23
-// CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 4 %c.var, ptr align 4 @C.val.loc19_3, i64 8, i1 false), !dbg !22
-// CHECK:STDOUT:   call void @_Z1FRN6Carbon1CE(ptr %c.var), !dbg !24
-// CHECK:STDOUT:   call void @"_COp.71e25083d63c4d6c:core.Destroy.Core"(ptr %c.var), !dbg !22
+// CHECK:STDOUT:   call void @"_COp.71e25083d63c4d6c:core.Destroy.Core"(ptr %self), !dbg !25
 // CHECK:STDOUT:   ret void, !dbg !25
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define weak_odr void @"_COp.7e389eab4a7e5487:core.Destroy.Core"(ptr %self) #1 !dbg !26 {
+// CHECK:STDOUT: define weak_odr void @"_COp.7e389eab4a7e5487:core.Destroy.Core"(ptr %self) #2 !dbg !26 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret void, !dbg !32
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define weak_odr void @"_COp.fb32c4dfca65e378:core.Destroy.Core"(ptr %self) #1 !dbg !33 {
+// CHECK:STDOUT: define weak_odr void @"_COp.fb32c4dfca65e378:core.Destroy.Core"(ptr %self) #2 !dbg !33 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   ret void, !dbg !39
+// CHECK:STDOUT:   ret void, !dbg !36
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define weak_odr void @"_COp.71e25083d63c4d6c:core.Destroy.Core"(ptr %self) #1 !dbg !40 {
+// CHECK:STDOUT: define weak_odr void @"_COp.71e25083d63c4d6c:core.Destroy.Core"(ptr %self) #2 !dbg !37 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   ret void, !dbg !43
+// CHECK:STDOUT:   ret void, !dbg !40
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CG.Main() #2 !dbg !41 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %c.var = alloca { i32, i32 }, align 8, !dbg !44
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %c.var), !dbg !44
+// CHECK:STDOUT:   %.loc19_29.3.a = getelementptr inbounds nuw { i32, i32 }, ptr %c.var, i32 0, i32 0, !dbg !45
+// CHECK:STDOUT:   %.loc19_29.6.b = getelementptr inbounds nuw { i32, i32 }, ptr %c.var, i32 0, i32 1, !dbg !45
+// CHECK:STDOUT:   call void @llvm.memcpy.p0.p0.i64(ptr align 4 %c.var, ptr align 4 @C.val.loc19_3, i64 8, i1 false), !dbg !44
+// CHECK:STDOUT:   call void @_Z1FRN6Carbon1CE(ptr %c.var), !dbg !46
+// CHECK:STDOUT:   call void @"_COp.71e25083d63c4d6c:core.Destroy.Core"(ptr %c.var), !dbg !44
+// CHECK:STDOUT:   ret void, !dbg !47
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #2
+// CHECK:STDOUT: declare void @llvm.lifetime.start.p0(ptr captures(none)) #3
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nocallback nofree nounwind willreturn memory(argmem: readwrite)
-// CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias writeonly captures(none), ptr noalias readonly captures(none), i64, i1 immarg) #3
+// CHECK:STDOUT: declare void @llvm.memcpy.p0.p0.i64(ptr noalias writeonly captures(none), ptr noalias readonly captures(none), i64, i1 immarg) #4
 // CHECK:STDOUT:
 // CHECK:STDOUT: attributes #0 = { mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #1 = { nounwind }
-// CHECK:STDOUT: attributes #2 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
-// CHECK:STDOUT: attributes #3 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT: attributes #1 = { alwaysinline nounwind }
+// CHECK:STDOUT: attributes #2 = { nounwind }
+// CHECK:STDOUT: attributes #3 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
+// CHECK:STDOUT: attributes #4 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!5}
@@ -380,28 +542,32 @@ fn G() {
 // CHECK:STDOUT: !16 = !{!17, !8, i64 0}
 // CHECK:STDOUT: !17 = !{!"_ZTSN6Carbon1CE", !8, i64 0, !8, i64 4}
 // CHECK:STDOUT: !18 = !{!17, !8, i64 4}
-// CHECK:STDOUT: !19 = distinct !DISubprogram(name: "G", linkageName: "_CG.Main", scope: null, file: !6, line: 18, type: !20, spFlags: DISPFlagDefinition, unit: !5)
+// CHECK:STDOUT: !19 = distinct !DISubprogram(name: "__destroy_thunk", linkageName: "_C__destroy_thunk:thunk.C.Main", scope: null, file: !6, line: 6, type: !20, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !23)
 // CHECK:STDOUT: !20 = !DISubroutineType(types: !21)
-// CHECK:STDOUT: !21 = !{null}
-// CHECK:STDOUT: !22 = !DILocation(line: 19, column: 3, scope: !19)
-// CHECK:STDOUT: !23 = !DILocation(line: 19, column: 14, scope: !19)
-// CHECK:STDOUT: !24 = !DILocation(line: 20, column: 3, scope: !19)
-// CHECK:STDOUT: !25 = !DILocation(line: 18, column: 1, scope: !19)
-// CHECK:STDOUT: !26 = distinct !DISubprogram(name: "Op", linkageName: "_COp.7e389eab4a7e5487:core.Destroy.Core", scope: null, file: !6, line: 19, type: !27, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !30)
+// CHECK:STDOUT: !21 = !{null, !22}
+// CHECK:STDOUT: !22 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 64)
+// CHECK:STDOUT: !23 = !{!24}
+// CHECK:STDOUT: !24 = !DILocalVariable(arg: 1, scope: !19, type: !22)
+// CHECK:STDOUT: !25 = !DILocation(line: 6, column: 1, scope: !19)
+// CHECK:STDOUT: !26 = distinct !DISubprogram(name: "Op", linkageName: "_COp.7e389eab4a7e5487:core.Destroy.Core", scope: null, file: !6, line: 6, type: !27, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !30)
 // CHECK:STDOUT: !27 = !DISubroutineType(types: !28)
 // CHECK:STDOUT: !28 = !{null, !29}
 // CHECK:STDOUT: !29 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
 // CHECK:STDOUT: !30 = !{!31}
 // CHECK:STDOUT: !31 = !DILocalVariable(arg: 1, scope: !26, type: !29)
-// CHECK:STDOUT: !32 = !DILocation(line: 19, column: 3, scope: !26)
-// CHECK:STDOUT: !33 = distinct !DISubprogram(name: "Op", linkageName: "_COp.fb32c4dfca65e378:core.Destroy.Core", scope: null, file: !6, line: 19, type: !34, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !37)
-// CHECK:STDOUT: !34 = !DISubroutineType(types: !35)
-// CHECK:STDOUT: !35 = !{null, !36}
-// CHECK:STDOUT: !36 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 64)
-// CHECK:STDOUT: !37 = !{!38}
-// CHECK:STDOUT: !38 = !DILocalVariable(arg: 1, scope: !33, type: !36)
-// CHECK:STDOUT: !39 = !DILocation(line: 19, column: 3, scope: !33)
-// CHECK:STDOUT: !40 = distinct !DISubprogram(name: "Op", linkageName: "_COp.71e25083d63c4d6c:core.Destroy.Core", scope: null, file: !6, line: 19, type: !34, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !41)
-// CHECK:STDOUT: !41 = !{!42}
-// CHECK:STDOUT: !42 = !DILocalVariable(arg: 1, scope: !40, type: !36)
-// CHECK:STDOUT: !43 = !DILocation(line: 19, column: 3, scope: !40)
+// CHECK:STDOUT: !32 = !DILocation(line: 6, column: 1, scope: !26)
+// CHECK:STDOUT: !33 = distinct !DISubprogram(name: "Op", linkageName: "_COp.fb32c4dfca65e378:core.Destroy.Core", scope: null, file: !6, line: 6, type: !20, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !34)
+// CHECK:STDOUT: !34 = !{!35}
+// CHECK:STDOUT: !35 = !DILocalVariable(arg: 1, scope: !33, type: !22)
+// CHECK:STDOUT: !36 = !DILocation(line: 6, column: 1, scope: !33)
+// CHECK:STDOUT: !37 = distinct !DISubprogram(name: "Op", linkageName: "_COp.71e25083d63c4d6c:core.Destroy.Core", scope: null, file: !6, line: 6, type: !20, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !38)
+// CHECK:STDOUT: !38 = !{!39}
+// CHECK:STDOUT: !39 = !DILocalVariable(arg: 1, scope: !37, type: !22)
+// CHECK:STDOUT: !40 = !DILocation(line: 6, column: 1, scope: !37)
+// CHECK:STDOUT: !41 = distinct !DISubprogram(name: "G", linkageName: "_CG.Main", scope: null, file: !6, line: 18, type: !42, spFlags: DISPFlagDefinition, unit: !5)
+// CHECK:STDOUT: !42 = !DISubroutineType(types: !43)
+// CHECK:STDOUT: !43 = !{null}
+// CHECK:STDOUT: !44 = !DILocation(line: 19, column: 3, scope: !41)
+// CHECK:STDOUT: !45 = !DILocation(line: 19, column: 14, scope: !41)
+// CHECK:STDOUT: !46 = !DILocation(line: 20, column: 3, scope: !41)
+// CHECK:STDOUT: !47 = !DILocation(line: 18, column: 1, scope: !41)
diff --git a/toolchain/lower/testdata/interop/cpp/reverse/method.carbon b/toolchain/lower/testdata/interop/cpp/reverse/method.carbon
index 24972d4ad41f..cdeb9f401246 100644
--- a/toolchain/lower/testdata/interop/cpp/reverse/method.carbon
+++ b/toolchain/lower/testdata/interop/cpp/reverse/method.carbon
@@ -3,6 +3,7 @@
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 // INCLUDE-FILE: toolchain/testing/testdata/min_prelude/int.carbon
+// EXTRA-ARGS: --clang-arg=-fno-exceptions
 //
 // AUTOUPDATE
 // TIP: To test this file alone, run:
@@ -69,13 +70,16 @@ fn CallCallF() { Cpp.CallF(); }
 // CHECK:STDOUT:
 // CHECK:STDOUT: %"class.Carbon::A" = type {}
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: mustprogress uwtable
+// CHECK:STDOUT: $_ZN6Carbon1AD2Ev = comdat any
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: mustprogress nounwind uwtable
 // CHECK:STDOUT: define dso_local void @_Z5CallFv() #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %ref.tmp = alloca %"class.Carbon::A", align 1
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %ref.tmp) #3
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %ref.tmp) #4
 // CHECK:STDOUT:   call void @_ZN6Carbon1A1FEv(ptr noundef nonnull align 1 dereferenceable(1) %ref.tmp)
-// CHECK:STDOUT:   call void @llvm.lifetime.end.p0(ptr %ref.tmp) #3
+// CHECK:STDOUT:   call void @_ZN6Carbon1AD2Ev(ptr noundef nonnull align 1 dereferenceable(1) %ref.tmp)
+// CHECK:STDOUT:   call void @llvm.lifetime.end.p0(ptr %ref.tmp) #4
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -92,26 +96,51 @@ fn CallCallF() { Cpp.CallF(); }
 // CHECK:STDOUT:   ret void
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: inlinehint mustprogress nounwind uwtable
+// CHECK:STDOUT: define linkonce_odr dso_local void @_ZN6Carbon1AD2Ev(ptr noundef nonnull align 1 dereferenceable(1) %this) unnamed_addr #3 comdat align 2 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %this.addr = alloca ptr, align 8
+// CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !11
+// CHECK:STDOUT:   %this1 = load ptr, ptr %this.addr, align 8
+// CHECK:STDOUT:   call void @"_C__destroy_thunk:thunk.A.Main"(ptr noundef nonnull align 1 dereferenceable(1) %this1)
+// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
 // CHECK:STDOUT: declare void @llvm.lifetime.end.p0(ptr captures(none)) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CF.A.Main(ptr %self) #3 !dbg !14 {
+// CHECK:STDOUT: define void @_CF.A.Main(ptr %self) #4 !dbg !14 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret void, !dbg !20
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CF__carbon_thunk.A.Main(ptr %self) #3 !dbg !21 {
+// CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
+// CHECK:STDOUT: define void @"_C__destroy_thunk:thunk.A.Main"(ptr %self) #5 !dbg !21 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   call void @_CF.A.Main(ptr %self), !dbg !24
+// CHECK:STDOUT:   call void @"_COp.1afa5e4ee26f3f8f:core.Destroy.Core"(ptr %self), !dbg !24
 // CHECK:STDOUT:   ret void, !dbg !24
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define weak_odr void @"_COp.1afa5e4ee26f3f8f:core.Destroy.Core"(ptr %self) #4 !dbg !25 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   ret void, !dbg !28
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CF__carbon_thunk.A.Main(ptr %self) #4 !dbg !29 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @_CF.A.Main(ptr %self), !dbg !32
+// CHECK:STDOUT:   ret void, !dbg !32
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: attributes #0 = { mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
 // CHECK:STDOUT: attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT: attributes #2 = { alwaysinline mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #3 = { nounwind }
+// CHECK:STDOUT: attributes #3 = { inlinehint mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #4 = { nounwind }
+// CHECK:STDOUT: attributes #5 = { alwaysinline nounwind }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!5}
@@ -138,10 +167,18 @@ fn CallCallF() { Cpp.CallF(); }
 // CHECK:STDOUT: !18 = !{!19}
 // CHECK:STDOUT: !19 = !DILocalVariable(arg: 1, scope: !14, type: !17)
 // CHECK:STDOUT: !20 = !DILocation(line: 6, column: 3, scope: !14)
-// CHECK:STDOUT: !21 = distinct !DISubprogram(name: "F__carbon_thunk", linkageName: "_CF__carbon_thunk.A.Main", scope: null, file: !6, line: 6, type: !15, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !22)
+// CHECK:STDOUT: !21 = distinct !DISubprogram(name: "__destroy_thunk", linkageName: "_C__destroy_thunk:thunk.A.Main", scope: null, file: !6, line: 5, type: !15, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !22)
 // CHECK:STDOUT: !22 = !{!23}
 // CHECK:STDOUT: !23 = !DILocalVariable(arg: 1, scope: !21, type: !17)
-// CHECK:STDOUT: !24 = !DILocation(line: 6, column: 3, scope: !21)
+// CHECK:STDOUT: !24 = !DILocation(line: 5, column: 1, scope: !21)
+// CHECK:STDOUT: !25 = distinct !DISubprogram(name: "Op", linkageName: "_COp.1afa5e4ee26f3f8f:core.Destroy.Core", scope: null, file: !6, line: 5, type: !15, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !26)
+// CHECK:STDOUT: !26 = !{!27}
+// CHECK:STDOUT: !27 = !DILocalVariable(arg: 1, scope: !25, type: !17)
+// CHECK:STDOUT: !28 = !DILocation(line: 5, column: 1, scope: !25)
+// CHECK:STDOUT: !29 = distinct !DISubprogram(name: "F__carbon_thunk", linkageName: "_CF__carbon_thunk.A.Main", scope: null, file: !6, line: 6, type: !15, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !30)
+// CHECK:STDOUT: !30 = !{!31}
+// CHECK:STDOUT: !31 = !DILocalVariable(arg: 1, scope: !29, type: !17)
+// CHECK:STDOUT: !32 = !DILocation(line: 6, column: 3, scope: !29)
 // CHECK:STDOUT: ; ModuleID = 'method_with_args_and_return.carbon'
 // CHECK:STDOUT: source_filename = "method_with_args_and_return.carbon"
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
@@ -149,13 +186,16 @@ fn CallCallF() { Cpp.CallF(); }
 // CHECK:STDOUT:
 // CHECK:STDOUT: %"class.Carbon::A" = type {}
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: mustprogress uwtable
+// CHECK:STDOUT: $_ZN6Carbon1AD2Ev = comdat any
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: mustprogress nounwind uwtable
 // CHECK:STDOUT: define dso_local noundef i32 @_Z5CallFv() #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   %ref.tmp = alloca %"class.Carbon::A", align 1
-// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %ref.tmp) #3
+// CHECK:STDOUT:   call void @llvm.lifetime.start.p0(ptr %ref.tmp) #4
 // CHECK:STDOUT:   %call = call noundef i32 @_ZN6Carbon1A1FEi(ptr noundef nonnull align 1 dereferenceable(1) %ref.tmp, i32 noundef 123)
-// CHECK:STDOUT:   call void @llvm.lifetime.end.p0(ptr %ref.tmp) #3
+// CHECK:STDOUT:   call void @_ZN6Carbon1AD2Ev(ptr noundef nonnull align 1 dereferenceable(1) %ref.tmp)
+// CHECK:STDOUT:   call void @llvm.lifetime.end.p0(ptr %ref.tmp) #4
 // CHECK:STDOUT:   ret i32 %call
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
@@ -176,35 +216,60 @@ fn CallCallF() { Cpp.CallF(); }
 // CHECK:STDOUT:   ret i32 %1
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: inlinehint mustprogress nounwind uwtable
+// CHECK:STDOUT: define linkonce_odr dso_local void @_ZN6Carbon1AD2Ev(ptr noundef nonnull align 1 dereferenceable(1) %this) unnamed_addr #3 comdat align 2 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %this.addr = alloca ptr, align 8
+// CHECK:STDOUT:   store ptr %this, ptr %this.addr, align 8, !tbaa !11
+// CHECK:STDOUT:   %this1 = load ptr, ptr %this.addr, align 8
+// CHECK:STDOUT:   call void @"_C__destroy_thunk:thunk.A.Main"(ptr noundef nonnull align 1 dereferenceable(1) %this1)
+// CHECK:STDOUT:   ret void
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: readwrite)
 // CHECK:STDOUT: declare void @llvm.lifetime.end.p0(ptr captures(none)) #1
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define i32 @_CF.A.Main(ptr %self, i32 %a) #3 !dbg !14 {
+// CHECK:STDOUT: define i32 @_CF.A.Main(ptr %self, i32 %a) #4 !dbg !14 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   ret i32 %a, !dbg !22
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CF__carbon_thunk.A.Main(ptr %self, ptr %_, ptr %_1) #3 !dbg !23 {
+// CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
+// CHECK:STDOUT: define void @"_C__destroy_thunk:thunk.A.Main"(ptr %self) #5 !dbg !23 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %.loc6_35.2 = load i32, ptr %_, align 4, !dbg !30
-// CHECK:STDOUT:   %A.F.call = call i32 @_CF.A.Main(ptr %self, i32 %.loc6_35.2), !dbg !30
-// CHECK:STDOUT:   store i32 %A.F.call, ptr %_1, align 4, !dbg !30
-// CHECK:STDOUT:   ret void, !dbg !30
+// CHECK:STDOUT:   call void @"_COp.1afa5e4ee26f3f8f:core.Destroy.Core"(ptr %self), !dbg !28
+// CHECK:STDOUT:   ret void, !dbg !28
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define i32 @_CCallCallF.Main() #3 !dbg !31 {
+// CHECK:STDOUT: define weak_odr void @"_COp.1afa5e4ee26f3f8f:core.Destroy.Core"(ptr %self) #4 !dbg !29 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   %CallF.call = call i32 @_Z5CallFv(), !dbg !34
-// CHECK:STDOUT:   ret i32 %CallF.call, !dbg !35
+// CHECK:STDOUT:   ret void, !dbg !32
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CF__carbon_thunk.A.Main(ptr %self, ptr %_, ptr %_1) #4 !dbg !33 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %.loc6_35.2 = load i32, ptr %_, align 4, !dbg !40
+// CHECK:STDOUT:   %A.F.call = call i32 @_CF.A.Main(ptr %self, i32 %.loc6_35.2), !dbg !40
+// CHECK:STDOUT:   store i32 %A.F.call, ptr %_1, align 4, !dbg !40
+// CHECK:STDOUT:   ret void, !dbg !40
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define i32 @_CCallCallF.Main() #4 !dbg !41 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %CallF.call = call i32 @_Z5CallFv(), !dbg !44
+// CHECK:STDOUT:   ret i32 %CallF.call, !dbg !45
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: attributes #0 = { mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
 // CHECK:STDOUT: attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
 // CHECK:STDOUT: attributes #2 = { alwaysinline mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
-// CHECK:STDOUT: attributes #3 = { nounwind }
+// CHECK:STDOUT: attributes #3 = { inlinehint mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: attributes #4 = { nounwind }
+// CHECK:STDOUT: attributes #5 = { alwaysinline nounwind }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!5}
@@ -233,25 +298,35 @@ fn CallCallF() { Cpp.CallF(); }
 // CHECK:STDOUT: !20 = !DILocalVariable(arg: 1, scope: !14, type: !18)
 // CHECK:STDOUT: !21 = !DILocalVariable(arg: 2, scope: !14, type: !17)
 // CHECK:STDOUT: !22 = !DILocation(line: 8, column: 5, scope: !14)
-// CHECK:STDOUT: !23 = distinct !DISubprogram(name: "F__carbon_thunk", linkageName: "_CF__carbon_thunk.A.Main", scope: null, file: !6, line: 6, type: !24, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !26)
+// CHECK:STDOUT: !23 = distinct !DISubprogram(name: "__destroy_thunk", linkageName: "_C__destroy_thunk:thunk.A.Main", scope: null, file: !6, line: 5, type: !24, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !26)
 // CHECK:STDOUT: !24 = !DISubroutineType(types: !25)
-// CHECK:STDOUT: !25 = !{null, !18, !17, !17}
-// CHECK:STDOUT: !26 = !{!27, !28, !29}
+// CHECK:STDOUT: !25 = !{null, !18}
+// CHECK:STDOUT: !26 = !{!27}
 // CHECK:STDOUT: !27 = !DILocalVariable(arg: 1, scope: !23, type: !18)
-// CHECK:STDOUT: !28 = !DILocalVariable(arg: 2, scope: !23, type: !17)
-// CHECK:STDOUT: !29 = !DILocalVariable(arg: 3, scope: !23, type: !17)
-// CHECK:STDOUT: !30 = !DILocation(line: 6, column: 3, scope: !23)
-// CHECK:STDOUT: !31 = distinct !DISubprogram(name: "CallCallF", linkageName: "_CCallCallF.Main", scope: null, file: !6, line: 18, type: !32, spFlags: DISPFlagDefinition, unit: !5)
-// CHECK:STDOUT: !32 = !DISubroutineType(types: !33)
-// CHECK:STDOUT: !33 = !{!17}
-// CHECK:STDOUT: !34 = !DILocation(line: 18, column: 32, scope: !31)
-// CHECK:STDOUT: !35 = !DILocation(line: 18, column: 25, scope: !31)
+// CHECK:STDOUT: !28 = !DILocation(line: 5, column: 1, scope: !23)
+// CHECK:STDOUT: !29 = distinct !DISubprogram(name: "Op", linkageName: "_COp.1afa5e4ee26f3f8f:core.Destroy.Core", scope: null, file: !6, line: 5, type: !24, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !30)
+// CHECK:STDOUT: !30 = !{!31}
+// CHECK:STDOUT: !31 = !DILocalVariable(arg: 1, scope: !29, type: !18)
+// CHECK:STDOUT: !32 = !DILocation(line: 5, column: 1, scope: !29)
+// CHECK:STDOUT: !33 = distinct !DISubprogram(name: "F__carbon_thunk", linkageName: "_CF__carbon_thunk.A.Main", scope: null, file: !6, line: 6, type: !34, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !36)
+// CHECK:STDOUT: !34 = !DISubroutineType(types: !35)
+// CHECK:STDOUT: !35 = !{null, !18, !17, !17}
+// CHECK:STDOUT: !36 = !{!37, !38, !39}
+// CHECK:STDOUT: !37 = !DILocalVariable(arg: 1, scope: !33, type: !18)
+// CHECK:STDOUT: !38 = !DILocalVariable(arg: 2, scope: !33, type: !17)
+// CHECK:STDOUT: !39 = !DILocalVariable(arg: 3, scope: !33, type: !17)
+// CHECK:STDOUT: !40 = !DILocation(line: 6, column: 3, scope: !33)
+// CHECK:STDOUT: !41 = distinct !DISubprogram(name: "CallCallF", linkageName: "_CCallCallF.Main", scope: null, file: !6, line: 18, type: !42, spFlags: DISPFlagDefinition, unit: !5)
+// CHECK:STDOUT: !42 = !DISubroutineType(types: !43)
+// CHECK:STDOUT: !43 = !{!17}
+// CHECK:STDOUT: !44 = !DILocation(line: 18, column: 32, scope: !41)
+// CHECK:STDOUT: !45 = !DILocation(line: 18, column: 25, scope: !41)
 // CHECK:STDOUT: ; ModuleID = 'static.carbon'
 // CHECK:STDOUT: source_filename = "static.carbon"
 // CHECK:STDOUT: target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
 // CHECK:STDOUT: target triple = "x86_64-unknown-linux-gnu"
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: mustprogress uwtable
+// CHECK:STDOUT: ; Function Attrs: mustprogress nounwind uwtable
 // CHECK:STDOUT: define dso_local void @_Z5CallFv() #0 {
 // CHECK:STDOUT: entry:
 // CHECK:STDOUT:   call void @_ZN6Carbon1A1FEv()
@@ -271,23 +346,37 @@ fn CallCallF() { Cpp.CallF(); }
 // CHECK:STDOUT:   ret void, !dbg !14
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CF__carbon_thunk.A.Main() #2 !dbg !15 {
+// CHECK:STDOUT: ; Function Attrs: alwaysinline nounwind
+// CHECK:STDOUT: define void @"_C__destroy_thunk:thunk.A.Main"(ptr %self) #3 !dbg !15 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   call void @_CF.A.Main(), !dbg !16
-// CHECK:STDOUT:   ret void, !dbg !16
+// CHECK:STDOUT:   call void @"_COp.1afa5e4ee26f3f8f:core.Destroy.Core"(ptr %self), !dbg !21
+// CHECK:STDOUT:   ret void, !dbg !21
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
 // CHECK:STDOUT: ; Function Attrs: nounwind
-// CHECK:STDOUT: define void @_CCallCallF.Main() #2 !dbg !17 {
+// CHECK:STDOUT: define weak_odr void @"_COp.1afa5e4ee26f3f8f:core.Destroy.Core"(ptr %self) #2 !dbg !22 {
 // CHECK:STDOUT: entry:
-// CHECK:STDOUT:   call void @_Z5CallFv(), !dbg !18
-// CHECK:STDOUT:   ret void, !dbg !19
+// CHECK:STDOUT:   ret void, !dbg !25
 // CHECK:STDOUT: }
 // CHECK:STDOUT:
-// CHECK:STDOUT: attributes #0 = { mustprogress uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CF__carbon_thunk.A.Main() #2 !dbg !26 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @_CF.A.Main(), !dbg !27
+// CHECK:STDOUT:   ret void, !dbg !27
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define void @_CCallCallF.Main() #2 !dbg !28 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   call void @_Z5CallFv(), !dbg !29
+// CHECK:STDOUT:   ret void, !dbg !30
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: attributes #0 = { mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
 // CHECK:STDOUT: attributes #1 = { alwaysinline mustprogress nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
 // CHECK:STDOUT: attributes #2 = { nounwind }
+// CHECK:STDOUT: attributes #3 = { alwaysinline nounwind }
 // CHECK:STDOUT:
 // CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4}
 // CHECK:STDOUT: !llvm.dbg.cu = !{!5}
@@ -308,8 +397,19 @@ fn CallCallF() { Cpp.CallF(); }
 // CHECK:STDOUT: !12 = !DISubroutineType(types: !13)
 // CHECK:STDOUT: !13 = !{null}
 // CHECK:STDOUT: !14 = !DILocation(line: 6, column: 3, scope: !11)
-// CHECK:STDOUT: !15 = distinct !DISubprogram(name: "F__carbon_thunk", linkageName: "_CF__carbon_thunk.A.Main", scope: null, file: !6, line: 6, type: !12, spFlags: DISPFlagDefinition, unit: !5)
-// CHECK:STDOUT: !16 = !DILocation(line: 6, column: 3, scope: !15)
-// CHECK:STDOUT: !17 = distinct !DISubprogram(name: "CallCallF", linkageName: "_CCallCallF.Main", scope: null, file: !6, line: 15, type: !12, spFlags: DISPFlagDefinition, unit: !5)
-// CHECK:STDOUT: !18 = !DILocation(line: 15, column: 18, scope: !17)
-// CHECK:STDOUT: !19 = !DILocation(line: 15, column: 1, scope: !17)
+// CHECK:STDOUT: !15 = distinct !DISubprogram(name: "__destroy_thunk", linkageName: "_C__destroy_thunk:thunk.A.Main", scope: null, file: !6, line: 5, type: !16, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !19)
+// CHECK:STDOUT: !16 = !DISubroutineType(types: !17)
+// CHECK:STDOUT: !17 = !{null, !18}
+// CHECK:STDOUT: !18 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 64)
+// CHECK:STDOUT: !19 = !{!20}
+// CHECK:STDOUT: !20 = !DILocalVariable(arg: 1, scope: !15, type: !18)
+// CHECK:STDOUT: !21 = !DILocation(line: 5, column: 1, scope: !15)
+// CHECK:STDOUT: !22 = distinct !DISubprogram(name: "Op", linkageName: "_COp.1afa5e4ee26f3f8f:core.Destroy.Core", scope: null, file: !6, line: 5, type: !16, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !23)
+// CHECK:STDOUT: !23 = !{!24}
+// CHECK:STDOUT: !24 = !DILocalVariable(arg: 1, scope: !22, type: !18)
+// CHECK:STDOUT: !25 = !DILocation(line: 5, column: 1, scope: !22)
+// CHECK:STDOUT: !26 = distinct !DISubprogram(name: "F__carbon_thunk", linkageName: "_CF__carbon_thunk.A.Main", scope: null, file: !6, line: 6, type: !12, spFlags: DISPFlagDefinition, unit: !5)
+// CHECK:STDOUT: !27 = !DILocation(line: 6, column: 3, scope: !26)
+// CHECK:STDOUT: !28 = distinct !DISubprogram(name: "CallCallF", linkageName: "_CCallCallF.Main", scope: null, file: !6, line: 15, type: !12, spFlags: DISPFlagDefinition, unit: !5)
+// CHECK:STDOUT: !29 = !DILocation(line: 15, column: 18, scope: !28)
+// CHECK:STDOUT: !30 = !DILocation(line: 15, column: 1, scope: !28)