[RFC][PATCH v2 0/2] objdump, libiberty: Implement short name search

[RFC][PATCH v2 0/2] objdump, libiberty: Implement short name search

[Mikołaj Piróg]

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This patch refines my previous attempt of implementing short name search (
https://sourceware.org/pipermail/binutils/2024-February/132713.html). The
idea is to enable such usage:

objdump --disassemble=ns::foo -C file

The objdump will then output all symbols matching the name "ns::foo".
I introduced new demangling option to remove template qualification, so for
example, "--dissassemble=std::vector::push_back" will match all instances
of push_back in the file.

The motivation behind this usage is to ease a process of a quick
disassembly of a binary in search for a particular function. Providing a
function signature isn't comfortable.

[RFC][PATCH v2 1/2] libiberty: implement option to drop templates during demangling

[Mikołaj Piróg]

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This patch introduces option that when given to cplus_demangle, drops
template from a symbol during demangling (in printing stage)

diff --git a/include/demangle.h b/include/demangle.h
index 49b84d4de88..89a3b64e436 100644
--- a/include/demangle.h
+++ b/include/demangle.h
@@ -51,6 +51,8 @@ extern "C" {
    types, even if present.  It applies
    only to the toplevel function type.
    */
+#define DMGL_TMPL_DROP   (1 << 7)       /* Supress printing of templates,
even
+   if present. */

 #define DMGL_AUTO (1 << 8)
 #define DMGL_GNU_V3 (1 << 14)
diff --git a/libiberty/cp-demangle.c b/libiberty/cp-demangle.c
index fc2cf64e6e0..ad873ed6177 100644
--- a/libiberty/cp-demangle.c
+++ b/libiberty/cp-demangle.c
@@ -5315,6 +5315,9 @@ d_print_comp_inner (struct d_print_info *dpi, int
options,
         else
           {
     d_print_comp (dpi, options, dcl);
+    if ((options & DMGL_TMPL_DROP) != 0)
+      return;
+
     if (d_last_char (dpi) == '<')
       d_append_char (dpi, ' ');
     d_append_char (dpi, '<');
@@ -5333,6 +5336,9 @@ d_print_comp_inner (struct d_print_info *dpi, int
options,
       }

     case DEMANGLE_COMPONENT_TEMPLATE_PARAM:
+      if ((options & DMGL_TMPL_DROP) != 0)
+ break;
+
       if (dpi->lambda_tpl_parms > dc->u.s_number.number + 1)
  {
   const struct demangle_component *a
@@ -5492,6 +5498,23 @@ d_print_comp_inner (struct d_print_info *dpi, int
options,
       return;

     case DEMANGLE_COMPONENT_SUB_STD:
+      /* Special-case substitions are stored wholly as a string. They need
+ to be stripped of templates manually */
+      if ((options & DMGL_TMPL_DROP) != 0)
+      {
+ char *template_begin = strchr(dc->u.s_string.string, '<');
+ if (template_begin != NULL)
+ {
+  d_append_buffer(dpi, dc->u.s_string.string, (template_begin -
dc->u.s_string.string));
+
+  char *template_end= strrchr(dc->u.s_string.string, '>');
+  if (template_end == NULL)
+    return;
+
+  d_append_buffer(dpi, template_end, dc->u.s_string.len - (template_end -
dc->u.s_string.string) - 1);
+  return;
+ }
+      }
       d_append_buffer (dpi, dc->u.s_string.string, dc->u.s_string.len);
       return;



pt., 8 mar 2024 o 19:04 Mikołaj Piróg <mikolajpirog@gmail.com> napisał(a):

> This patch refines my previous attempt of implementing short name search (
> https://sourceware.org/pipermail/binutils/2024-February/132713.html). The
> idea is to enable such usage:
>
> objdump --disassemble=ns::foo -C file
>
> The objdump will then output all symbols matching the name "ns::foo".
> I introduced new demangling option to remove template qualification, so for
> example, "--dissassemble=std::vector::push_back" will match all instances
> of push_back in the file.
>
> The motivation behind this usage is to ease a process of a quick
> disassembly of a binary in search for a particular function. Providing a
> function signature isn't comfortable.
>
>
>
>
>
>
>

[RFC][PATCH v2 2/2] objdump: Implement short name search

[Mikołaj Piróg]

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Implement short name search. When objdump is used like so:

objdump --disassemble=sym -C file

It will attempt to decide if "sym" is a short name or a regular name. If it
is a short name, it will search for symbols matching given name.

diff --git a/binutils/objdump.c b/binutils/objdump.c
index 7beb221cb2f..21c4b86bf3d 100644
--- a/binutils/objdump.c
+++ b/binutils/objdump.c
@@ -138,6 +138,9 @@ static bool extended_color_output = false; /*
--visualize-jumps=extended-color.
 static int process_links = false;       /* --process-links.  */
 static int show_all_symbols;            /* --show-all-symbols.  */
 static bool decompressed_dumps = false; /* -Z, --decompress.  */
+static bool short_name_search = false;  /* True when demangling is used,
disasm_sym
+   is given and appears to be
+   a short name */

 static enum color_selection
   {
@@ -3905,7 +3908,10 @@ disassemble_section (bfd *abfd, asection *section,
void *inf)
       if (do_demangle && name[0] != '\0')
  {
   /* Demangle the name.  */
-  alloc = bfd_demangle (abfd, name, demangle_flags);
+  if (short_name_search)
+    alloc = bfd_demangle (abfd, name, DMGL_TMPL_DROP);
+  else
+    alloc = bfd_demangle (abfd, name, demangle_flags);
   if (alloc != NULL)
     name = alloc;
  }
@@ -3923,7 +3929,7 @@ disassemble_section (bfd *abfd, asection *section,
void *inf)
    (*rel_pp)->address - rel_offset < sym_offset)
   ++rel_pp;

-  if (sym->flags & BSF_FUNCTION)
+  if (sym->flags & BSF_FUNCTION && !(short_name_search && do_demangle))
     {
       if (bfd_get_flavour (abfd) == bfd_target_elf_flavour
   && ((elf_symbol_type *) sym)->internal_elf_sym.st_size > 0)
@@ -5879,7 +5885,18 @@ display_file (char *filename, char *target, bool
last_file)
   else
     bfd_close_all_done (file);
 }
-
+
+/* Attempts to determine if a given name represents a short name of a
symbol.
+   Short name of a symbol is name without a signature and template
qualification. */
+static bool is_short_name(const char *name) {
+  char *begin = strchr(name, '(');
+  char *end = strchr(name, ')');
+  if (end - begin <= 1)
+    return true;
+
+  return false;
+}
+
 int
 main (int argc, char **argv)
 {
@@ -6255,6 +6272,9 @@ main (int argc, char **argv)
  }
     }

+  if (disasm_sym != NULL && do_demangle)
+    short_name_search = is_short_name(disasm_sym);
+
   if (disassembler_color == on_if_terminal_output)
     disassembler_color = isatty (1) ? on : off;



pt., 8 mar 2024 o 19:04 Mikołaj Piróg <mikolajpirog@gmail.com> napisał(a):

> This patch refines my previous attempt of implementing short name search (
> https://sourceware.org/pipermail/binutils/2024-February/132713.html). The
> idea is to enable such usage:
>
> objdump --disassemble=ns::foo -C file
>
> The objdump will then output all symbols matching the name "ns::foo".
> I introduced new demangling option to remove template qualification, so for
> example, "--dissassemble=std::vector::push_back" will match all instances
> of push_back in the file.
>
> The motivation behind this usage is to ease a process of a quick
> disassembly of a binary in search for a particular function. Providing a
> function signature isn't comfortable.
>
>
>
>
>
>
>

Re: [RFC][PATCH v2 1/2] libiberty: implement option to drop templates during demangling

[Nick Clifton]

Hi Mikołaj,

> This patch introduces option that when given to cplus_demangle, drops template from a symbol during demangling (in printing stage)

I am not sure if I have mentioned this already but the libiberty sources
are maintained by the GCC folks, not us.  So in order to get this patch
in you will need to submit it to them...

Cheers
   Nick