[lldb-dev] Acceptance of dwarf2/3 suggested form of DW_AT_comp_dir
mg11 at csr.com
Thu Aug 21 02:25:23 PDT 2014
The DWARF2/3 standard specifies DW_AT_comp_dir as follows:
A DW_AT_comp_dir attribute whose value is a null-terminated string
current working directory of the compilation command that produced this
in whatever form makes sense for the host system.
/The suggested form for the value of the DW_AT_comp_dir attribute on U
NIX systems is//
//‘‘hostname:pathname’’. If no hostname is available, the suggested form
The section in italics (see the spec. for yourselves) is unfortunate,
since in the Introduction we are told that italicised text are "not part
of the format definition itself", but by using the word "suggested" in
the definition the implies compliance with the definition.
Consulting the DWARF4 standard's definition I see that the errant
italicised text has been removed. (I say errant because in my opinion,
the suggested form, contradicts the earlier requirement "makes sense for
the host system", as the hostname:pathname or :pathname forms are not
acceptable to the UNIXs stat or open functions).
I note that the earlier versions of gcc ignored this "suggested form".
Unfortunately the toolchain which I'm using follows the suggested form
for UNIX systems, e.g.:
This isn't currently acceptable to lldb, since when I am stepping an
inferior, the DisplaySourceLinesXXX functions fail to perform, due to
GetFileStats predictably failing when ::stat is passed a
hostname:pathname style of string.
Now I could get our toolchain fixed (so that it ignores DWARF2's
suggestion, and encodes only the pathname), but I wondered whether it
was worth seeing how the rest of the lldb community feels regarding
supporting the suggested DWARF2/3 form.
Member of the CSR plc group of companies. CSR plc registered in England and Wales, registered number 4187346, registered office Churchill House, Cambridge Business Park, Cowley Road, Cambridge, CB4 0WZ, United Kingdom
More information can be found at www.csr.com. Keep up to date with CSR on our technical blog, www.csr.com/blog, CSR people blog, www.csr.com/people, YouTube, www.youtube.com/user/CSRplc, Facebook, www.facebook.com/pages/CSR/191038434253534, or follow us on Twitter at www.twitter.com/CSR_plc.
New for 2014, you can now access the wide range of products powered by aptX at www.aptx.com.
More information about the lldb-dev