Re: [PATCH] Replace sort_tu_by_abbrev_offset with operator<

[Vaseeharan Vinayagamoorthy <Vaseeharan.Vinayagamoorthy@arm.com>]

I am seeing this error: passing ‘const tu_abbrev_offset’ as ‘this’ argument of ‘bool tu_abbrev_offset::operator<(const tu_abbrev_offset&)’ discards qualifiers [-fpermissive]
  

In file included from /usr/include/c++/4.8.2/algorithm:62:0,
                 from /src/binutils-gdb--gdb/gdb/dwarf2/read.c:85:
/usr/include/c++/4.8.2/bits/stl_algo.h: In instantiation of ‘_RandomAccessIterator std::__unguarded_partition(_RandomAccessIterator, _RandomAccessIterator, const _Tp&) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<tu_abbrev_offset*, std::vector<tu_abbrev_offset> >; _Tp = tu_abbrev_offset]’:
/usr/include/c++/4.8.2/bits/stl_algo.h:2283:70:   required from ‘_RandomAccessIterator std::__unguarded_partition_pivot(_RandomAccessIterator, _RandomAccessIterator) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<tu_abbrev_offset*, std::vector<tu_abbrev_offset> >]’
/usr/include/c++/4.8.2/bits/stl_algo.h:2315:54:   required from ‘void std::__introsort_loop(_RandomAccessIterator, _RandomAccessIterator, _Size) [with _RandomAccessIterator = __gnu_cxx::__normal_iterator<tu_abbrev_offset*, std::vector<tu_abbrev_offset> >; _Size = long int]’
/usr/include/c++/4.8.2/bits/stl_algo.h:5461:36:   required from ‘void std::sort(_RAIter, _RAIter) [with _RAIter = __gnu_cxx::__normal_iterator<tu_abbrev_offset*, std::vector<tu_abbrev_offset> >]’
/src/binutils-gdb--gdb/gdb/dwarf2/read.c:7195:64:   required from here
/usr/include/c++/4.8.2/bits/stl_algo.h:2245:19: error: passing ‘const tu_abbrev_offset’ as ‘this’ argument of ‘bool tu_abbrev_offset::operator<(const tu_abbrev_offset&)’ discards qualifiers [-fpermissive]
    while (__pivot < *__last)


The build/host/target setup is:
Build: x86_64 (Linux)
Host: : x86_64 (Linux)
Target: arm-none-eabi / arm-none-linux-gnueabi  / aarch64-none-elf / aarch64-none-linux-gnu


Kind regards
Vasee


On 15/05/2021, 16:19, "Gdb-patches on behalf of Tom Tromey" <gdb-patches-bounces@sourceware.org on behalf of tom@tromey.com> wrote:

    I noticed that sort_tu_by_abbrev_offset only has a single caller.  It
    seemed simpler to replace it with an implementation of operator<
    instead.

    gdb/ChangeLog
    2021-05-15  Tom Tromey  <tom@tromey.com>

    	* dwarf2/read.c (tu_abbrev_offset::operator<): New method.
    	(sort_tu_by_abbrev_offset): Remove.
    	(build_type_psymtabs): Update.
    ---
     gdb/ChangeLog     |  6 ++++++
     gdb/dwarf2/read.c | 18 +++++++-----------
     2 files changed, 13 insertions(+), 11 deletions(-)

    diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
    index ac786abf6d2..f1bb9b2f3df 100644
    --- a/gdb/dwarf2/read.c
    +++ b/gdb/dwarf2/read.c
    @@ -7351,19 +7351,16 @@ struct tu_abbrev_offset
       : sig_type (sig_type_), abbrev_offset (abbrev_offset_)
       {}

    +  /* This is used when sorting.  */
    +  bool operator< (const tu_abbrev_offset &other)
    +  {
    +    return abbrev_offset < other.abbrev_offset;
    +  }
    +
       signatured_type *sig_type;
       sect_offset abbrev_offset;
     };

    -/* Helper routine for build_type_psymtabs, passed to std::sort.  */
    -
    -static bool
    -sort_tu_by_abbrev_offset (const struct tu_abbrev_offset &a,
    -			  const struct tu_abbrev_offset &b)
    -{
    -  return a.abbrev_offset < b.abbrev_offset;
    -}
    -
     /* Efficiently read all the type units.

        The efficiency is because we sort TUs by the abbrev table they use and
    @@ -7431,8 +7428,7 @@ build_type_psymtabs (dwarf2_per_objfile *per_objfile)
     	}
         }

    -  std::sort (sorted_by_abbrev.begin (), sorted_by_abbrev.end (),
    -	     sort_tu_by_abbrev_offset);
    +  std::sort (sorted_by_abbrev.begin (), sorted_by_abbrev.end ());

       abbrev_offset = (sect_offset) ~(unsigned) 0;

    -- 
    2.26.3