December 8, 2007

  Had to add an ugly configure conditional as libelf has

  unconditional use of off64_t in recent libelf.h

July 3, 2007

  A new interface function, dwarf_loclist_from_expr(),

  allows easy extraction of dwarf expression bytes from

  expressions in frame data.

May 8, 2007

  Now documents released as .mm and .pdf (no longer as .ps).

May 7, 2007

  Incorporates Sun Microsystems  extensions to dwarf.h and

  to the consumer and producer libraries.   The changes

  include corrections so the producer library  cleans up it's memory

  use on a call to dwarf_producer_finish(dbg).

  Thanks to Chris Quenelle of Sun for these contributions.

March 20, 2007

  nroff/troff and the AT&T -mm package are not widely available,

  so now the Makefile refers to groff, which works quite nicely.

February 20, 2007

  Documented libdwarf thread safety in README.

  Fixed memory leak in  dwarf macro reading code.

  Removed use of static data in dwarf macro

  reading code: now uses stack/heap (for

  thread safety).

February 9, 2007

  Maintenance of libdwarf is now outside SGI

  as David Anderson has left SGI.

March 29, 2006

  The March  27, 2006 version accomodates DWARF3.

  Some people have been using the library without

  altering dwarf.h, libdwarf.h to accomodate

  large numbers of registers.  This exposed a bug

  (an off-by-one error) but also makes it clear

  additional documentation is needed.  So 

  in libdwarf large new comments near 'TARGET DEPENDENCY'

  attempt to explain better.

Oct 03, 2005

  The July version had an incompatible interface: old

  dealloc code did not always work right. The incompatibility

  is now fixed and the new features remain.

July 15, 2005

  New optional alloc-check code optionally checks all

  allocated memory is freed (malloc_check.h malloc_check.c)

  Various new dealloc routines written as the previous approach

  of letting client code do detailed dealloc turned out not

  to dealloc all memory.

  To get the new checking you must manually change a line

  in malloc_check.h and rebuild libdwarf.

Mar 31, 2005

  Documented  the libexc.so/.debug_funcnames

  dependency and the 64bit-offset DWARF extension in

  mips_extentions.{mm,ps}.

Mar 21, 2005

  gcc 3.3 and 3.4 .eh_frame 'z' augmentations are not handled

  correctly, so libdwarf gives an error when attempting to

  print such. gcc 2 'eh' augmentation is simpler and

  prints correctly.  (.eh_frame is a GNU section,

  not DWARF2/3, and what is recorded in .eh_frame is not

  specified by DWARF2/3, though .eh_frame does resemble

  DWARF2/3 .debug_frame).

Oct 28, 2004

  Updated contact address in copyright: SGI moved 1/4 mile

  in 2003 to a new address: 1500 Crittenden Lane.

  Documented additional vendor extensions.

Oct 27, 2004

  Added known vendor extensions to dwarf2/3 to dwarf.h

  HP, GNU, PGI and UPC extensions are now recorded.

  Recorded vendor extensions from Concurrent.

Feb 3, 2004

  If 'Dwarf_Word' is 64 bits, two macros reading leb numbers

  fail to initialize upper bits of the values read.

  First noticed with bogus line numbers printing from dwarfdump.

  Now we use already-existing functions, avoiding the problem.

Oct 02, 2003

  Support .debug_loc section fully.

Sept 29, 2003

  Support DW_FORM_indirect properly.

  Supports loclists in part (but not multiple loclist entries yet).

  Support 'padding bytes' at end of .debug_arange and

  .debug_pubnames and .debug_pubtypes per CU

  (recent dwarf committee email made it clear this is appropriate).

May 23, 2002

  Libdwarf now asks for sections only when they are

  used, so that unneeded sections aren't loaded.

  Support for using SGI's ELF library as an alternative to

  using AT&T libelf-style has been added (the SGI ELF

  library is presently only available internally to SGI).

Jan 10, 2002

  Fixed memory leak in dwarf_finish().

Aug 21, 2001

  If one called dwarf_add_file_decl()

  or dwarf_add_directory_decl() but never added a line,

  .debug_line was not produced.  This was a mistake,

  as if any file or directory was provided .debug_line

  should be produced. Now it is produced.

June 14, 2001

  Given a cu header offset, it was not easy to derive the

  CU header DIE offset. Created the new

  function dwarf_get_cu_die_offset_given_cu_header_offset()

  do get the CU header DIE offset.

  Added the function dwarf_get_arange_cu_header_offset()

  so the cu header offset could be retrieved from .debug_aranges

  information.

June 07, 2001

  Major bug in dwarf_leb.c decoding large integers 

  (Dwarf_Signed 64 bit where library is compiled in ILP32) 

  found and fixed.

May 21, 2001

  Some small fixes have been found by various folks,

  so it seems time to prepare a new source release.

  See ChangeLog for details.

April 15, 2000

  The libdwarf copyright has changed to

     version 2.1 of the GNU Lesser General Public License.

  Anyone holding a version of libdwarf that was published

  before this new copyright is allowed to use

    the copyright published in that earlier libdwarf source

    on the earlier source

  or to use 

    this new copyright on the earlier source,

  at their option.

December 08, 1999

  The dwarf committee has adopted the offset-extension

  proposal. This allows compatibly emitting

  dwarf with 64bit offsets.

  The dwarf reader now automatically figures out which is in use.

  The dwarf writer configures itself at the time the

  writer initialization routine is called, though

  the writer is restricted, at libdwarf 

  compile time, to one of

		mips/sgi pure 32/pure 64 offsets/pointers.

		32bit offsets only (per dwarf 2.0.0 and cygnus)

		32bit offsets with extension to 64bit offsets

		allowed (the offset-extension newly passed).

  In addition, a great deal of duplicate code

  for the sgi  .debug_weaknames, .debug_funcnames, 

  .debug_varnames and .debug_typenames sections has

  been removed: a single set of functions does the real work now.

Sept 29, 1999

  Just found out that cygnus is, on 64bit targets, generating

  32bit offsets (as elf32 has, for example) with 64 bit

  pointers (in references to text and data).

  Whereas sgi has always generated 64bit dwarf with

  64 bit offsets (as in elf64) and 64bit pointers for

  64bit pointer objects.

  I'll call the sgi approach 64-bit and the cygnus approach

  32bit-offsets.

  Cygnus is following the DWARF2 spec as written, so they are

  right in doing only 32bit-offsets.

  Folks at sgi (including me) think that, as for elf64,

  the offsets in dwarf for 64bit pointer-apps should be

  64 bits.  We think it is only a matter of time

  before we really *need* 64bit offsets and when that happens

  it will be on an important app.  Disk space is cheap,

  so lets just go 64 bit on 64bit apps (such as ia64 apps)

  to avoid a future problem.

  I(davea@sgi.com) think the 'pointer-size' references in the dwarf

  spec were really written for 64-bit pointer apps.

  I don't recall serious consideration of 64bit pointer

  apps in the committee deliberations (I did miss

  a couple of meetings) and think 64bit offsets

  are consistent with dwarf2, even though the speci

  was not written for such. We think true full 64 bit

  dwarf2 is the right way to go (the spec changes

  are obvious: file and section offsets become 64bit

  with 64bit pointer objects.

  MIPS/SGI is definitely 64-bit offsets for 64 bit objects,

  cygnus is definitely 32bit-offsets for earlier 64bit pointer

  environments.

  At any rate, now the dwarf reader allows and accomodates

  both and the dwarf producer also accomodates both.

  Some tweaking of the pro_init.c or dwarf_init_finish.c

  files may be necessary in future: no other changes should

  be needed to accomodate the two 64bit approaches, as

  the library (and dwarfdump) now deal with both forms.

August 20, 1999

  Added some #ifndef/#define to pro_util.h to let libdwarf build

  on more hosts.  (since those hosts don't need the producer

  code, AFAIK, zero values suffice for missing #defines.)

July 21, 1999

  Now reader transparently reads either-endianness data

  from an either-endianness object.

  Updated dwarf.h and libdwarf.h to recognize

  GNU egcs dwarf extensions and to print the egcs eh_frame

  section.

June 10, 1999

  gnu configure version of libdwarf made available for the

  first time.  

  Still allows only same-endian-as-host in objects.

August, 1994

  libdwarf source made available for ftp on sgigate.sgi.com

	/ftp/pub

June, 1994

  Consumer interface changed completely, following

  "Candy Machine Interfaces" chapter from

   "Writing Solid Code" by Steve Maguire (Microsoft Press).

April,  1993

  Initial version of libdwarf  for dwarf version 2

  written at sgi.