Test binaries created with the following commands:

$ cat container.cpp
#include "container.h"
#include <stdlib.h>

struct Container_ivars {
  // real definition here
};

ContainerPtr allocateContainer() {
  Container *c = (Container *)malloc(sizeof(Container));
  c->ivars = (Container_ivars *)malloc(sizeof(Container_ivars));
  return c;
}

extern void doSomething(ContainerPtr);

int main() {
  ContainerPtr c = allocateContainer();
  doSomething(c);
  return 0;
}

$ cat container.h
struct Container_ivars;

struct Container {
  union {
    struct Container_ivars *ivars;
  };
};

typedef Container *ContainerPtr;

$ cat use.cpp
#include "container.h"

void doSomething(ContainerPtr c) {}


$ clang++ -O0 -g container.cpp -c -o container.o
$ clang++ -O0 -g use.cpp -c -o use.o
$ clang++ use.o container.o -o a.out

Note that the link order in the last command matters for this test.

RUN: dsymutil -oso-prepend-path %p/../Inputs %p/../Inputs/private/tmp/union/a.out -o %t.dSYM
RUN: llvm-dwarfdump %t.dSYM | FileCheck %s

CHECK: DW_TAG_compile_unit

CHECK:          DW_AT_name      ("Container_ivars")
CHECK-NEXT:     DW_AT_declaration       (true)

CHECK: DW_TAG_compile_unit

CHECK:          DW_AT_name      ("Container_ivars")
CHECK-NEXT:     DW_AT_byte_size (0x01)
CHECK-NEXT:     DW_AT_decl_file ("{{.*}}container.cpp")
CHECK-NEXT:     DW_AT_decl_line (4)