Compilation Unit name

Fri Mar 17 17:18:00 GMT 2017

I did not find the reference about the argument named next_cu_header_offset (below I pasted the respective functions signatures). 
Anyway, name orthography apart, what is being used in Dyninst with libdwarf is exactly the value of what we called next_cu_off, which corresponds to the third parameter of dwarf_nextcu(), named in libdw as next_off.

Do you have any other thoughts why the sequence of function calls is not working, instead it is giving invalid dwarf?

// libdw
/* Read the header for the DWARF CU. */    
extern int dwarf_nextcu (Dwarf *dwarf, Dwarf_Off off, Dwarf_Off *next_off, 
         size_t *header_sizep, Dwarf_Off *abbrev_offsetp,
         uint8_t *address_sizep, uint8_t *offset_sizep)      __nonnull_attribute__ (3); 

// libdwarf
     dwarf_next_cu_header_c(Dwarf_Debug dbg, Dwarf_Bool is_info, Dwarf_Unsigned *cu_length,
	 Dwarf_Half *cu_version, Dwarf_Off *cu_abbrev_offset, Dwarf_Half *cu_pointer_size,
	 Dwarf_Half *cu_offset_size, Dwarf_Half *cu_extension_size, Dwarf_Sig8 *type_signature,
	 Dwarf_Unsigned *type_offset, Dwarf_Unsigned *cu_next_offset, Dwarf_Error *err);

De: Josh Stone <>
Enviado: quinta-feira, 16 de março de 2017 19:29:12
Assunto: Re: Compilation Unit name
Stick to plain text, not HTML, if you want to reach the list.

On 03/16/2017 03:44 PM, SASHA NICOLAS DA ROCHA PINHEIRO wrote:
> I had that before, and it didn't work, then I empirically changed to
> next_cu_off because it contained the same offset I was supposed to get
> when I compared to the libdwarf execution. 

What you have called cu_die_off is *not* a die offset!  In libdwarf.h
that argument is called next_cu_header_offset, which is why it has the
same value as the next_cu_off you're getting from libdw.

> We already discarded the option of using dwarf_offdie_types since
> previously, with libdwarf, it was passed true to:

That's fine and correct.  You shouldn't use dwarf_offdie_types now, I
was trying to preempt a future problem.  Sorry for adding confusion.


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