Status 2008-12-15

[Petr Machata <pmachata at redhat dot com>]

= Work done last week:

  * I spent around 80% of time on elfutils work this week.

  * Read roadmap and a write-up about dwarflint.

  * Merge monotone trunk into my sharing & threads branches.  Fix what 
got broken, commit.

  * Initial work on dwarflint.  Current status is as follows:

     - It loads .debug_abbrev, doing checks for validity of various 
fields along the way.  LEB128s are checked for overflow.  All reads are 
checked that they don't pass outside the section data.

     - It uses this abbrev table to load .debug_info.  Again, if a range 
of allowed values is given, fields are validated.  Invalid and unused 
abbrev codes are detected.  DIE references are checked to point to 
actual DIE beginnings, as opposed to a bunch of bytes that happens to be 
interpretable as a DIE.  DIEs whose abbreviation has_children are 
checked to actually have non-zero children.

     - String references are marked and holes of unused bytes in 
.dwarf_str are reported.

     - Most of that can't be considered tested.  I tried a couple 
debuginfo files (emacs, libX11, libsc680lx from OpenOffice).  debuginfo 
files often seem to contain unused .debug_str bytes.  Non-zero DIEs 
followed by zero DIEs are reported for libsc680lx, which is suspicious 
and likely a bug in lint.  False positives of this type will have to be 
fixed as the producer development proceeds.

     - The implementation should be reasonably snappy for normal-sized 
files.  I tried to lint OpenOffice's libsc680lx, a 130MB debuginfo file, 
and it takes a bit under six seconds on my 2G core2 machine; so there 
may be a room for improvement, but I don't think it's pressing.

     - The code sits on pmachata/dwarflint branch.  My thinking is that 
when the producer branch is created, this branch gets merged in and 
deleted, and further development will take place on producer branch.

= Work scheduled for next week:

  * My plan for this week doesn't leave room for any serious elfutils 
work at all.  If something changes, I'll work on:

   - dwarflint fixes
   - correct DW_AT_sibling attribute value
   - checks of other sections (aranges, ranges, locs)

= Holidays:

  * My plan is to have the last day this Friday (19th), and come back 
5th January.  But odds are good that I'll grow bored and work on 
something anyway.

PM

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