Import dynamic-ness of a C++ class (#7141)

toolchain/check/cpp/import.cpp

@@ -848,6 +848,8 @@ static auto BuildClassDefinition(Context& context,
 
   class_info.inheritance_kind = GetInheritanceKind(clang_def);
 
+  class_info.is_dynamic = clang_def->isDynamicClass();
+
   // Compute the class's object representation.
   auto object_repr_id = ImportClassObjectRepr(
       context, class_id, import_ir_inst_id, class_inst_id, clang_def);

toolchain/lower/testdata/interop/cpp/class/import/dynamic.carbon

@@ -0,0 +1,89 @@
+// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+// Exceptions. See /LICENSE for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+// INCLUDE-FILE: toolchain/testing/testdata/min_prelude/primitives.carbon
+//
+// AUTOUPDATE
+// TIP: To test this file alone, run:
+// TIP:   bazel test //toolchain/testing:file_test --test_arg=--file_tests=toolchain/lower/testdata/interop/cpp/class/import/dynamic.carbon
+// TIP: To dump output, run:
+// TIP:   bazel run //toolchain/testing:file_test -- --dump_output --file_tests=toolchain/lower/testdata/interop/cpp/class/import/dynamic.carbon
+
+// --- dynamic_base_from_cpp.carbon
+
+library "[[@TEST_NAME]]";
+
+import Cpp;
+
+inline Cpp '''
+
+struct Base {
+  int i;
+  virtual void func();
+};
+
+''';
+
+base class Derived {
+  extend base: Cpp.Base;
+  virtual fn other_func[self: Self]();
+}
+
+fn Use(d: Derived) -> i32 {
+  d.other_func();
+  return d.i;
+}
+
+// CHECK:STDOUT: ; ModuleID = 'dynamic_base_from_cpp.carbon'
+// CHECK:STDOUT: source_filename = "dynamic_base_from_cpp.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: @"_CDerived.Main.$vtable" = unnamed_addr constant [1 x i32] [i32 trunc (i64 sub (i64 ptrtoint (ptr @_Cother_func.Derived.Main to i64), i64 ptrtoint (ptr @"_CDerived.Main.$vtable" to i64)) to i32)]
+// CHECK:STDOUT:
+// CHECK:STDOUT: declare void @_Cother_func.Derived.Main(ptr)
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nounwind
+// CHECK:STDOUT: define i32 @_CUse.Main(ptr %d) #0 !dbg !11 {
+// CHECK:STDOUT: entry:
+// CHECK:STDOUT:   %Derived.other_func.call.vtable = load ptr, ptr %d, align 8, !dbg !18
+// CHECK:STDOUT:   %Derived.other_func.call = call ptr @llvm.load.relative.i32(ptr %Derived.other_func.call.vtable, i32 0), !dbg !18
+// CHECK:STDOUT:   call void %Derived.other_func.call(ptr %d), !dbg !18
+// CHECK:STDOUT:   %.loc22_11.1.base = getelementptr inbounds nuw { [16 x i8] }, ptr %d, i32 0, i32 0, !dbg !19
+// CHECK:STDOUT:   %.loc22_11.3.i = getelementptr inbounds nuw [16 x i8], ptr %.loc22_11.1.base, i32 0, i32 8, !dbg !19
+// CHECK:STDOUT:   %.loc22_11.4 = load i32, ptr %.loc22_11.3.i, align 4, !dbg !19
+// CHECK:STDOUT:   ret i32 %.loc22_11.4, !dbg !20
+// CHECK:STDOUT: }
+// CHECK:STDOUT:
+// CHECK:STDOUT: ; Function Attrs: nocallback nofree nosync nounwind willreturn memory(argmem: read)
+// CHECK:STDOUT: declare ptr @llvm.load.relative.i32(ptr, i32) #1
+// CHECK:STDOUT:
+// CHECK:STDOUT: attributes #0 = { nounwind }
+// CHECK:STDOUT: attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: read) }
+// CHECK:STDOUT:
+// CHECK:STDOUT: !llvm.module.flags = !{!0, !1, !2, !3, !4}
+// CHECK:STDOUT: !llvm.dbg.cu = !{!5}
+// CHECK:STDOUT: !llvm.errno.tbaa = !{!7}
+// CHECK:STDOUT:
+// CHECK:STDOUT: !0 = !{i32 7, !"Dwarf Version", i32 5}
+// CHECK:STDOUT: !1 = !{i32 2, !"Debug Info Version", i32 3}
+// CHECK:STDOUT: !2 = !{i32 8, !"PIC Level", i32 2}
+// CHECK:STDOUT: !3 = !{i32 7, !"PIE Level", i32 2}
+// CHECK:STDOUT: !4 = !{i32 7, !"uwtable", i32 2}
+// CHECK:STDOUT: !5 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !6, producer: "carbon", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug)
+// CHECK:STDOUT: !6 = !DIFile(filename: "dynamic_base_from_cpp.carbon", directory: "")
+// CHECK:STDOUT: !7 = !{!8, !8, i64 0}
+// CHECK:STDOUT: !8 = !{!"int", !9, i64 0}
+// CHECK:STDOUT: !9 = !{!"omnipotent char", !10, i64 0}
+// CHECK:STDOUT: !10 = !{!"Simple C++ TBAA"}
+// CHECK:STDOUT: !11 = distinct !DISubprogram(name: "Use", linkageName: "_CUse.Main", scope: null, file: !6, line: 20, type: !12, spFlags: DISPFlagDefinition, unit: !5, retainedNodes: !16)
+// CHECK:STDOUT: !12 = !DISubroutineType(types: !13)
+// CHECK:STDOUT: !13 = !{!14, !15}
+// CHECK:STDOUT: !14 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+// CHECK:STDOUT: !15 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: null, size: 64)
+// CHECK:STDOUT: !16 = !{!17}
+// CHECK:STDOUT: !17 = !DILocalVariable(arg: 1, scope: !11, type: !15)
+// CHECK:STDOUT: !18 = !DILocation(line: 21, column: 3, scope: !11)
+// CHECK:STDOUT: !19 = !DILocation(line: 22, column: 10, scope: !11)
+// CHECK:STDOUT: !20 = !DILocation(line: 22, column: 3, scope: !11)