Re: [PATCH v2 0/4] elfutils: DWARF package (.dwp) file support

[Omar Sandoval <osandov@osandov.com>]

On Wed, Dec 06, 2023 at 01:22:15AM -0800, Omar Sandoval wrote:
> From: Omar Sandoval <osandov@fb.com>
> 
> Hi,
> 
> This is version 2 of my patch series adding support for DWARF package
> files to libdw and the elfutils tools. Version 1 is here [1].
> 
> Patches 1-3 add the main implementation and tests for dwp files.
> 
> Most of this support is internal to libdw, but patch 1 adds a new public
> function, dwarf_cu_dwp_section_info. drgn's dwp branch [2] demonstrates
> how that function will be used. Also see [3] for more context on why
> drgn needs this.
> 
> Patch 4 adds support and tests for an LLVM extension to the dwp format.
> The "extension" is ugly because of an oversight in the design of the
> format that LLVM had to make the best of, but unfortunately it's
> necessary for a lot of our use cases.
> 
> With this patch series, drgn's test suite passes against a Linux kernel
> build using .dwp.
> 
> Changes from v1:
> 
> * Rebased on main and dropped patches that were already merged.
> * Moved ChangeLog entries to commit messages.
> * Updated version in libdw.map to 0.191.
> * Moved DW_SECT_TYPES definition to dwarf.h.
> * Added copyright years.
> * Added error handling for dwarf_cu_dwp_section_info calls in
>   str_offsets_base_off, __libdw_cu_ranges_base, and __libdw_cu_locs_base
> * Changed memset initialization of index->sections to an explicit
>   loop.
> * Added comment explaining __libdw_link_skel_split change.
> 
> There were a couple of things that were mentioned in review that I
> didn't change:
> 
> * I kept dwarf_cu_dwp_section_info in patch 1 instead of separating it
>   into its own patch so that I could test the dwp index implementation
>   in the same commit that I introduced it in.
> * I didn't make try_dwp_file return an error since try_split_file that
>   it's based on doesn't either.
> 
> Thanks!
> Omar
> 
> 1: https://sourceware.org/pipermail/elfutils-devel/2023q3/006410.html
> 2: https://github.com/osandov/drgn/tree/dwp
> 3: https://sourceware.org/pipermail/elfutils-devel/2023q4/006630.html
> 
> Omar Sandoval (4):
>   libdw: Parse DWARF package file index sections
>   libdw: Try .dwp file in __libdw_find_split_unit()
>   libdw: Apply DWARF package file section offsets where appropriate
>   libdw: Handle overflowed DW_SECT_INFO offsets in DWARF package file
>     indexes

Ping, and happy new year :)