Take the following program:

::::::::::::::
header.hxx
::::::::::::::
#include <malloc.h>

class Heap
{
  private:
    char *_memory;
    size_t _size;
  public:
    Heap();
    void* allocate  (size_t size);
    static size_t header_size();
};
::::::::::::::
heap.cxx
::::::::::::::
#include "header.hxx"

size_t
Heap::header_size ()
{
  return 42;
}

Heap::Heap()
{
  _size = header_size () + 32;
  _memory = (char *) malloc (_size);
}

void*
Heap::allocate(size_t size)
{
  _size += size;
  return _memory + header_size();
}
::::::::::::::
main.cxx
::::::::::::::
#include "header.hxx"

int size (int resize)
{
  return (int)Heap::header_size() - resize;
}

int
main (int argc, char **argv)
{
  return size (argc);
}

Compile it with g++ 4.7.1:

$ g++ -g -O2 -c main.cxx
$ g++ -g -O2 -c heap.cxx
$ g++ -g main.o heap.o -o prog

Inspect it with:
$ eu-readelf --debug-dump=info prog
[...]
 [     b]  compile_unit
           producer             (strp) "GNU C++ 4.7.1 20120629 (Red Hat 4.7.1-1) -fpreprocessed -mtune=generic -march=x86-64 -g -O2"
           language             (data1) C++ (4)
           name                 (strp) "main.cxx"
           comp_dir             (strp) "/home/mark/src/tests/cxx-decl"
           ranges               (sec_offset) range list [     0]
           low_pc               (addr) 000000000000000000
           stmt_list            (sec_offset) 0
[...]
 [   289]    class_type
             name                 (strp) "Heap"
             byte_size            (data1) 16
             decl_file            (data1) 6
             decl_line            (data1) 3
             sibling              (ref4) [   2a6]
 [   295]      subprogram
               external             (flag_present) Yes
               name                 (strp) "header_size"
               decl_file            (data1) 6
               decl_line            (data1) 11
               linkage_name         (strp) "_ZN4Heap11header_sizeEv"
               type                 (ref4) [    30]
               accessibility        (data1) public (1)
               declaration          (flag_present) Yes
 [   38e]  compile_unit
           producer             (strp) "GNU C++ 4.7.1 20120629 (Red Hat 4.7.1-1) -fpreprocessed -mtune=generic -march=x86-64 -g -O2"
           language             (data1) C++ (4)
           name                 (strp) "heap.cxx"
           comp_dir             (strp) "/home/mark/src/tests/cxx-decl"
           low_pc               (addr) 0x00000000004005b0 <_ZN4Heap11header_sizeEv>
           high_pc              (addr) 0x00000000004005ec
           stmt_list            (sec_offset) 220
[...]
 [   610]    class_type
             name                 (strp) "Heap"
             byte_size            (data1) 16
             decl_file            (data1) 5
             decl_line            (data1) 3
             sibling              (ref4) [   67e]
 [   61c]      member
               name                 (strp) "_memory"
               decl_file            (data1) 5
               decl_line            (data1) 6
               type                 (ref4) [   412]
               data_member_location (data1) 0
 [   628]      member
               name                 (strp) "_size"
               decl_file            (data1) 5
               decl_line            (data1) 7
               type                 (ref4) [   3b7]
               data_member_location (data1) 8
 [   634]      subprogram
               external             (flag_present) Yes
               name                 (strp) "Heap"
               decl_file            (data1) 5
               decl_line            (data1) 9
               accessibility        (data1) public (1)
               declaration          (flag_present) Yes
               object_pointer       (ref4) [   644]
               sibling              (ref4) [   64a]
 [   644]        formal_parameter
                 type                 (ref4) [   67e]
                 artificial           (flag_present) Yes
 [   64a]      subprogram
               external             (flag_present) Yes
               name                 (strp) "allocate"
               decl_file            (data1) 5
               decl_line            (data1) 10
               linkage_name         (strp) "_ZN4Heap8allocateEm"
               type                 (ref4) [   410]
               accessibility        (data1) public (1)
               declaration          (flag_present) Yes
               object_pointer       (ref4) [   662]
               sibling              (ref4) [   66d]
 [   662]        formal_parameter
                 type                 (ref4) [   67e]
                 artificial           (flag_present) Yes
 [   667]        formal_parameter
                 type                 (ref4) [   3b7]
 [   66d]      subprogram
               external             (flag_present) Yes
               name                 (strp) "header_size"
               decl_file            (data1) 5
               decl_line            (data1) 11
               linkage_name         (strp) "_ZN4Heap11header_sizeEv"
               type                 (ref4) [   3b7]
               accessibility        (data1) public (1)
               declaration          (flag_present) Yes

Note how the first one in the main.cxx compile_unit is incomplete.
It only contains the header_size subprogram member (since that is the only member used in main.cxx).

By just looking at the class_type DIE we cannot tell which one we need, since both [   289] and [   610] look identical, both have a byte_size attribute and neither is marked as declaration.

Shouldn't DIE [   289] somehow be marked as partial? Either by not setting DW_AT_byte_size and/or adding DW_AT_declaration?

This causes systemtap bug http://sourceware.org/bugzilla/show_bug.cgi?id=14434 "dwflpp sometimes caches incomplete class_type".