Re: [ping] [PATCH v3] Replace solib_global_lookup with gdbarch_iterate_over_objfiles_in_search_order

["Christian Biesinger via gdb-patches" <gdb-patches@sourceware.org>]

ping

On Tue, Sep 10, 2019 at 11:35 PM Christian Biesinger
<cbiesinger@google.com> wrote:
>
> ping
>
> On Tue, Aug 27, 2019 at 6:03 PM Christian Biesinger
> <cbiesinger@google.com> wrote:
> >
> > [Test solib-corrupted.exp is now fixed]
> >
> > All implementations of either function use it for the same purpose (except
> > Darwin, which is a no-op): to prefer a symbol in the current objfile over
> > symbols with the same name in other objfiles. There does not seem to be a
> > reason to have both mechanisms for that purpose.
> >
> > gdb/ChangeLog:
> >
> > 2019-08-27  Christian Biesinger  <cbiesinger@google.com>
> >
> >         * solib-darwin.c (darwin_lookup_lib_symbol): Remove.
> >         (_initialize_darwin_solib): Don't set
> >         darwin_so_ops.lookup_lib_global_symbol.
> >         * solib-spu.c (spu_lookup_lib_symbol): Rename to...
> >         (spu_iterate_over_objfiles_in_search_order): ...this,
> >         and update to the iterate semantics.
> >         (set_spu_solib_ops): Instead of setting lookup_lib_global_symbol,
> >         call set_gdbarch_iterate_over_objfiles_in_search_order.
> >         * solib-svr4.c (set_solib_svr4_fetch_link_map_offsets): Call
> >         set_gdbarch_iterate_over_objfiles_in_search_order.
> >         (elf_lookup_lib_symbol): Rename to...
> >         (svr4_iterate_over_objfiles_in_search_order): this, and update
> >         to iterate semantics.
> >         (_initialize_svr4_solib): Don't set lookup_lib_global_symbol.
> >         * solib-svr4.h: Declare svr4_iterate_over_objfiles_in_search_order.
> >         * solib.c (solib_global_lookup): Remove.
> >         * solist.h (struct target_so_ops): Remove lookup_lib_global_symbol.
> >         (solib_global_lookup): Remove.
> >         * symtab.c (lookup_global_or_static_symbol): Remove call to
> >         solib_global_lookup.
> > ---
> >  gdb/solib-darwin.c |  9 ---------
> >  gdb/solib-spu.c    | 27 ++++++++++++++------------
> >  gdb/solib-svr4.c   | 48 ++++++++++++++++++++++++++++------------------
> >  gdb/solib-svr4.h   |  5 +++++
> >  gdb/solib.c        | 15 ---------------
> >  gdb/solist.h       | 11 -----------
> >  gdb/symtab.c       |  6 +-----
> >  7 files changed, 50 insertions(+), 71 deletions(-)
> >
> > diff --git a/gdb/solib-darwin.c b/gdb/solib-darwin.c
> > index 443ebb64a4..b386cd35ed 100644
> > --- a/gdb/solib-darwin.c
> > +++ b/gdb/solib-darwin.c
> > @@ -638,14 +638,6 @@ darwin_relocate_section_addresses (struct so_list *so,
> >      so->addr_low = sec->addr;
> >  }
> >
> > -static struct block_symbol
> > -darwin_lookup_lib_symbol (struct objfile *objfile,
> > -                         const char *name,
> > -                         const domain_enum domain)
> > -{
> > -  return {};
> > -}
> > -
> >  static gdb_bfd_ref_ptr
> >  darwin_bfd_open (const char *pathname)
> >  {
> > @@ -688,6 +680,5 @@ _initialize_darwin_solib (void)
> >    darwin_so_ops.current_sos = darwin_current_sos;
> >    darwin_so_ops.open_symbol_file_object = open_symbol_file_object;
> >    darwin_so_ops.in_dynsym_resolve_code = darwin_in_dynsym_resolve_code;
> > -  darwin_so_ops.lookup_lib_global_symbol = darwin_lookup_lib_symbol;
> >    darwin_so_ops.bfd_open = darwin_bfd_open;
> >  }
> > diff --git a/gdb/solib-spu.c b/gdb/solib-spu.c
> > index 5b97b9bcf6..ed33a0adf2 100644
> > --- a/gdb/solib-spu.c
> > +++ b/gdb/solib-spu.c
> > @@ -385,19 +385,21 @@ spu_bfd_open (const char *pathname)
> >    return abfd;
> >  }
> >
> > -/* Lookup global symbol in a SPE executable.  */
> > -static struct block_symbol
> > -spu_lookup_lib_symbol (struct objfile *objfile,
> > -                      const char *name,
> > -                      const domain_enum domain)
> > +/* Search order prefers the current objfile for SPE executables.  */
> > +static void
> > +spu_iterate_over_objfiles_in_search_order
> > +  (struct gdbarch *gdbarch,
> > +   iterate_over_objfiles_in_search_order_cb_ftype *cb,
> > +   void *cb_data, struct objfile *objfile)
> >  {
> > -  if (bfd_get_arch (objfile->obfd) == bfd_arch_spu)
> > -    return lookup_global_symbol_from_objfile (objfile, GLOBAL_BLOCK, name,
> > -                                             domain);
> > +  if (objfile != nullptr && bfd_get_arch (objfile->obfd) == bfd_arch_spu)
> > +    {
> > +      if (cb (objfile, cb_data) != 0)
> > +       return;
> > +    }
> >
> > -  if (svr4_so_ops.lookup_lib_global_symbol != NULL)
> > -    return svr4_so_ops.lookup_lib_global_symbol (objfile, name, domain);
> > -  return {};
> > +  return svr4_iterate_over_objfiles_in_search_order(
> > +    gdbarch, cb, cb_data, objfile);
> >  }
> >
> >  /* Enable shared library breakpoint.  */
> > @@ -515,9 +517,10 @@ set_spu_solib_ops (struct gdbarch *gdbarch)
> >        spu_so_ops.free_so = spu_free_so;
> >        spu_so_ops.current_sos = spu_current_sos;
> >        spu_so_ops.bfd_open = spu_bfd_open;
> > -      spu_so_ops.lookup_lib_global_symbol = spu_lookup_lib_symbol;
> >      }
> >
> > +  set_gdbarch_iterate_over_objfiles_in_search_order
> > +    (gdbarch, spu_iterate_over_objfiles_in_search_order);
> >    set_solib_ops (gdbarch, &spu_so_ops);
> >  }
> >
> > diff --git a/gdb/solib-svr4.c b/gdb/solib-svr4.c
> > index c0c505acaa..e595a3572b 100644
> > --- a/gdb/solib-svr4.c
> > +++ b/gdb/solib-svr4.c
> > @@ -3104,6 +3104,8 @@ set_solib_svr4_fetch_link_map_offsets (struct gdbarch *gdbarch,
> >    ops->fetch_link_map_offsets = flmo;
> >
> >    set_solib_ops (gdbarch, &svr4_so_ops);
> > +  set_gdbarch_iterate_over_objfiles_in_search_order
> > +    (gdbarch, svr4_iterate_over_objfiles_in_search_order);
> >  }
> >
> >  /* Fetch a link_map_offsets structure using the architecture-specific
> > @@ -3202,32 +3204,41 @@ svr4_lp64_fetch_link_map_offsets (void)
> >
> >  struct target_so_ops svr4_so_ops;
> >
> > -/* Lookup global symbol for ELF DSOs linked with -Bsymbolic.  Those DSOs have a
> > +/* Search order for ELF DSOs linked with -Bsymbolic.  Those DSOs have a
> >     different rule for symbol lookup.  The lookup begins here in the DSO, not in
> >     the main executable.  */
> >
> > -static struct block_symbol
> > -elf_lookup_lib_symbol (struct objfile *objfile,
> > -                      const char *name,
> > -                      const domain_enum domain)
> > +void
> > +svr4_iterate_over_objfiles_in_search_order
> > +  (struct gdbarch *gdbarch,
> > +   iterate_over_objfiles_in_search_order_cb_ftype *cb,
> > +   void *cb_data, struct objfile *current_objfile)
> >  {
> > -  bfd *abfd;
> > -
> > -  if (objfile == symfile_objfile)
> > -    abfd = exec_bfd;
> > -  else
> > +  if (current_objfile != nullptr)
> >      {
> > -      /* OBJFILE should have been passed as the non-debug one.  */
> > -      gdb_assert (objfile->separate_debug_objfile_backlink == NULL);
> > +      bfd *abfd;
> >
> > -      abfd = objfile->obfd;
> > -    }
> > +      if (current_objfile->separate_debug_objfile_backlink != nullptr)
> > +        current_objfile = current_objfile->separate_debug_objfile_backlink;
> >
> > -  if (abfd == NULL || scan_dyntag (DT_SYMBOLIC, abfd, NULL, NULL) != 1)
> > -    return {};
> > +      if (current_objfile == symfile_objfile)
> > +       abfd = exec_bfd;
> > +      else
> > +       abfd = current_objfile->obfd;
> > +
> > +      if (abfd != nullptr &&
> > +         scan_dyntag (DT_SYMBOLIC, abfd, nullptr, nullptr) == 1)
> > +       {
> > +         if (cb (current_objfile, cb_data) != 0)
> > +           return;
> > +       }
> > +    }
> >
> > -  return lookup_global_symbol_from_objfile (objfile, GLOBAL_BLOCK, name,
> > -                                           domain);
> > +  for (objfile *objfile : current_program_space->objfiles ())
> > +    {
> > +      if (cb (objfile, cb_data) != 0)
> > +       return;
> > +    }
> >  }
> >
> >  void
> > @@ -3244,7 +3255,6 @@ _initialize_svr4_solib (void)
> >    svr4_so_ops.open_symbol_file_object = open_symbol_file_object;
> >    svr4_so_ops.in_dynsym_resolve_code = svr4_in_dynsym_resolve_code;
> >    svr4_so_ops.bfd_open = solib_bfd_open;
> > -  svr4_so_ops.lookup_lib_global_symbol = elf_lookup_lib_symbol;
> >    svr4_so_ops.same = svr4_same;
> >    svr4_so_ops.keep_data_in_core = svr4_keep_data_in_core;
> >    svr4_so_ops.update_breakpoints = svr4_update_solib_event_breakpoints;
> > diff --git a/gdb/solib-svr4.h b/gdb/solib-svr4.h
> > index a051e70b79..b99b8e2e3a 100644
> > --- a/gdb/solib-svr4.h
> > +++ b/gdb/solib-svr4.h
> > @@ -21,6 +21,7 @@
> >  #define SOLIB_SVR4_H
> >
> >  #include "solist.h"
> > +#include "gdbarch.h"
> >
> >  struct objfile;
> >  struct target_so_ops;
> > @@ -107,4 +108,8 @@ extern struct link_map_offsets *svr4_lp64_fetch_link_map_offsets (void);
> >     SVR4 run time loader.  */
> >  int svr4_in_dynsym_resolve_code (CORE_ADDR pc);
> >
> > +extern void svr4_iterate_over_objfiles_in_search_order (
> > +  struct gdbarch *gdbarch, iterate_over_objfiles_in_search_order_cb_ftype *cb,
> > +  void *cb_data, struct objfile *objfile);
> > +
> >  #endif /* solib-svr4.h */
> > diff --git a/gdb/solib.c b/gdb/solib.c
> > index 29a17ad5d4..ec3bf06c50 100644
> > --- a/gdb/solib.c
> > +++ b/gdb/solib.c
> > @@ -1441,21 +1441,6 @@ show_auto_solib_add (struct ui_file *file, int from_tty,
> >  }
> >
> >
> > -/* Handler for library-specific lookup of global symbol NAME in OBJFILE.  Call
> > -   the library-specific handler if it is installed for the current target.  */
> > -
> > -struct block_symbol
> > -solib_global_lookup (struct objfile *objfile,
> > -                    const char *name,
> > -                    const domain_enum domain)
> > -{
> > -  const struct target_so_ops *ops = solib_ops (target_gdbarch ());
> > -
> > -  if (ops->lookup_lib_global_symbol != NULL)
> > -    return ops->lookup_lib_global_symbol (objfile, name, domain);
> > -  return {};
> > -}
> > -
> >  /* Lookup the value for a specific symbol from dynamic symbol table.  Look
> >     up symbol from ABFD.  MATCH_SYM is a callback function to determine
> >     whether to pick up a symbol.  DATA is the input of this callback
> > diff --git a/gdb/solist.h b/gdb/solist.h
> > index e1410c2b79..ee99fc815b 100644
> > --- a/gdb/solist.h
> > +++ b/gdb/solist.h
> > @@ -139,12 +139,6 @@ struct target_so_ops
> >                               unsigned o_flags,
> >                               gdb::unique_xmalloc_ptr<char> *temp_pathname);
> >
> > -  /* Hook for looking up global symbols in a library-specific way.  */
> > -  struct block_symbol (*lookup_lib_global_symbol)
> > -    (struct objfile *objfile,
> > -     const char *name,
> > -     const domain_enum domain);
> > -
> >    /* Given two so_list objects, one from the GDB thread list
> >       and another from the list returned by current_sos, return 1
> >       if they represent the same library.
> > @@ -209,9 +203,4 @@ extern gdb_bfd_ref_ptr solib_bfd_open (const char *in_pathname);
> >  /* FIXME: gdbarch needs to control this variable.  */
> >  extern struct target_so_ops *current_target_so_ops;
> >
> > -/* Handler for library-specific global symbol lookup in solib.c.  */
> > -struct block_symbol solib_global_lookup (struct objfile *objfile,
> > -                                           const char *name,
> > -                                           const domain_enum domain);
> > -
> >  #endif
> > diff --git a/gdb/symtab.c b/gdb/symtab.c
> > index 7762c85708..c74f39c3cd 100644
> > --- a/gdb/symtab.c
> > +++ b/gdb/symtab.c
> > @@ -2637,11 +2637,7 @@ lookup_global_or_static_symbol (const char *name,
> >        return result;
> >      }
> >
> > -  /* Call library-specific lookup procedure.  */
> > -  if (objfile != NULL)
> > -    result = solib_global_lookup (objfile, name, domain);
> > -
> > -  /* If that didn't work go a global search (of global blocks, heh).  */
> > +  /* Do a global search (of global blocks, heh).  */
> >    if (result.symbol == NULL)
> >      {
> >        memset (&lookup_data, 0, sizeof (lookup_data));
> > --
> > 2.23.0.187.g17f5b7556c-goog
> >