[RFC,SCHEME_B,2/7] objdump, readelf: sframe: apply relocations before textual dump

Message ID 20250407002559.6593-3-indu.bhagat@oracle.com
State New
Headers
Series Fix relocatable links with SFrame section |

Checks

Context Check Description
linaro-tcwg-bot/tcwg_binutils_build--master-aarch64 warning Skipped upon request
linaro-tcwg-bot/tcwg_binutils_build--master-arm warning Skipped upon request

Commit Message

Indu Bhagat April 7, 2025, 12:25 a.m. UTC
  PR libsframe/32589 - function start address is zero in SFrame section dump

Currently, readelf and objdump display SFrame section in object file
with function start addresses of each function as 0.  This makes it
difficult to correlate SFrame stack trace information with the
individual functions in the object file.

For objdump, use the dump_dwarf () interface to dump SFrame section.
Similarly, for readelf, use the display_debug_section () interface to
dump SFrame section.  These current interfaces (for DWARF debug
sections) already supports relocating the section contents before
dumping, so lets use that for SFrame sections as well.

When adding a new entry for SFrame in debug_option_table[], use char
'nil' and the option name of "sframe-internal-only".  This is done so
that there is no additional (unnecessary) user-exposed ways of dumping
SFrame sections.  Additionally, we explicitly disallow the
"sframe-internal-only" from external/user input in --dwarf (objdump).
Similarly, "sframe-internal-only" is explicitly matched and disallowed
from --debug-dump (readelf).

For objdump and readelf, we continue to keep the same error messaging as
earlier:

$ objdump --sframe=sframe bubble_sort.o
...
No sframe section present

$ objdump --sframe=.sfram bubble_sort.o
...
No .sfram section present

$ objdump --sframe=sframe-internal-only sort
...
No sframe-internal-only section present

Similarly for readelf:

$ readelf --sframe= bubble_sort.o
readelf: Error: Section name must be provided
$ readelf --sframe=.sfram bubble_sort.o
readelf: Warning: Section '.sfram' was not dumped because it does not exist
$ readelf --sframe=sframe bubble_sort.o
readelf: Warning: Section 'sframe' was not dumped because it does not exist

binutils/
        * dwarf.c (display_sframe): New definition.
        (dwarf_select_sections_all): Enable SFrame section too.
        (struct dwarf_section_display): Add entry for SFrame section.
        * dwarf.h (enum dwarf_section_display_enum): Add enumerator for
	SFrame.
        * objdump.c (dump_section_sframe): Remove.
        (dump_sframe_section): Add new definition.
        (dump_bfd): Use dump_sframe_section.
        * binutils/readelf.c (dump_section_as_sframe): Remove.

gas/testsuite/
        * gas/cfi-sframe/cfi-sframe-aarch64-pac-ab-key-1.d: Adjust for
	new output.

----
Notes:

This patch is the same as that for Scheme#A RFC
https://inbox.sourceware.org/binutils/20250331185205.3755087-1-indu.bhagat@oracle.com/.

The next patch in sequence ("[RFC,SCHEME#B 3/7] libsframe: process FDE
function start addr before dumping") shows the diff necessary for
adopting Scheme#B in the current patch.
---
 binutils/dwarf.c                              | 35 +++++++++++
 binutils/dwarf.h                              |  1 +
 binutils/objdump.c                            | 59 +++++++------------
 binutils/readelf.c                            | 50 ++++------------
 .../cfi-sframe-aarch64-pac-ab-key-1.d         |  8 +--
 5 files changed, 72 insertions(+), 81 deletions(-)
  

Patch

diff --git a/binutils/dwarf.c b/binutils/dwarf.c
index 08bb623e405..50e8d480716 100644
--- a/binutils/dwarf.c
+++ b/binutils/dwarf.c
@@ -30,6 +30,7 @@ 
 #include "gdb/gdb-index.h"
 #include "filenames.h"
 #include "safe-ctype.h"
+#include "sframe-api.h"
 #include <assert.h>
 
 #ifdef HAVE_LIBDEBUGINFOD
@@ -102,6 +103,7 @@  int do_debug_str;
 int do_debug_str_offsets;
 int do_debug_loc;
 int do_gdb_index;
+int do_sframe;
 int do_trace_info;
 int do_trace_abbrevs;
 int do_trace_aranges;
@@ -7678,6 +7680,37 @@  display_trace_info (struct dwarf_section *section, void *file)
   return process_debug_info (section, file, section->abbrev_sec, false, true);
 }
 
+static int
+display_sframe (struct dwarf_section *section, void *file ATTRIBUTE_UNUSED)
+{
+  sframe_decoder_ctx *sfd_ctx = NULL;
+  unsigned char *data = section->start;
+  size_t sf_size = section->size;
+  int err = 0;
+
+  if (strcmp (section->name, "") == 0)
+    {
+      error (_("Section name must be provided \n"));
+      return false;
+    }
+
+  /* Decode the contents of the section.  */
+  sfd_ctx = sframe_decode ((const char*)data, sf_size, &err);
+  if (!sfd_ctx || err)
+    {
+      error (_("SFrame decode failure: %s\n"), sframe_errmsg (err));
+      return false;
+    }
+
+  printf (_("Contents of the SFrame section %s:"), section->name);
+  /* Dump the contents as text.  */
+  dump_sframe (sfd_ctx, section->address);
+
+  sframe_decoder_free (&sfd_ctx);
+
+  return true;
+}
+
 static int
 display_debug_aranges (struct dwarf_section *section,
 		       void *file ATTRIBUTE_UNUSED)
@@ -12648,6 +12681,7 @@  static const debug_dump_long_opts debug_option_table[] =
   /* For compatibility with earlier versions of readelf.  */
   { 'r', "ranges", &do_debug_aranges, 1 },
   { 's', "str", &do_debug_str, 1 },
+  { '\0', "sframe-internal-only", &do_sframe, 1 },
   { 'T', "trace_aranges", &do_trace_aranges, 1 },
   { 't', "pubtypes", &do_debug_pubtypes, 1 },
   { 'U', "trace_info", &do_trace_info, 1 },
@@ -12806,6 +12840,7 @@  struct dwarf_section_display debug_displays[] =
   { { ".debug_weaknames",   ".zdebug_weaknames",     "",	 NO_ABBREVS },	    display_debug_not_supported, NULL,		false },
   { { ".gdb_index",	    "",			     "",	 NO_ABBREVS },	    display_gdb_index,	    &do_gdb_index,	false },
   { { ".debug_names",	    "",			     "",	 NO_ABBREVS },	    display_debug_names,    &do_gdb_index,	false },
+  { { ".sframe",	    "",			     "",	 NO_ABBREVS },	    display_sframe,	    &do_sframe,		true },
   { { ".trace_info",	    "",			     "",	 ABBREV (trace_abbrev) }, display_trace_info, &do_trace_info,	true },
   { { ".trace_abbrev",	    "",			     "",	 NO_ABBREVS },	    display_debug_abbrev,   &do_trace_abbrevs,	false },
   { { ".trace_aranges",	    "",			     "",	 NO_ABBREVS },	    display_debug_aranges,  &do_trace_aranges,	false },
diff --git a/binutils/dwarf.h b/binutils/dwarf.h
index 3419027ac1e..6f693b1eac2 100644
--- a/binutils/dwarf.h
+++ b/binutils/dwarf.h
@@ -102,6 +102,7 @@  enum dwarf_section_display_enum
   weaknames,
   gdb_index,
   debug_names,
+  sframe,
   trace_info,
   trace_abbrev,
   trace_aranges,
diff --git a/binutils/objdump.c b/binutils/objdump.c
index 8fdbe03c4fb..343c5530c1e 100644
--- a/binutils/objdump.c
+++ b/binutils/objdump.c
@@ -4981,44 +4981,20 @@  dump_ctf (bfd *abfd ATTRIBUTE_UNUSED, const char *sect_name ATTRIBUTE_UNUSED,
 #endif
 
 static void
-dump_section_sframe (bfd *abfd ATTRIBUTE_UNUSED,
-		     const char * sect_name)
-{
-  asection *sec;
-  sframe_decoder_ctx *sfd_ctx = NULL;
-  bfd_size_type sf_size;
-  bfd_byte *sframe_data;
-  bfd_vma sf_vma;
-  int err = 0;
-
-  if (sect_name == NULL)
-    sect_name = ".sframe";
+dump_sframe_section (bfd *abfd, const char *sect_name, bool is_mainfile)
 
-  sec = read_section (abfd, sect_name, &sframe_data);
-  if (sec == NULL)
-    {
-      my_bfd_nonfatal (bfd_get_filename (abfd));
-      return;
-    }
-  sf_size = bfd_section_size (sec);
-  sf_vma = bfd_section_vma (sec);
-
-  /* Decode the contents of the section.  */
-  sfd_ctx = sframe_decode ((const char*)sframe_data, sf_size, &err);
-  if (!sfd_ctx)
+{
+  /* Error checking for user provided SFrame section name, if any.  */
+  if (sect_name)
     {
-      my_bfd_nonfatal (bfd_get_filename (abfd));
-      free (sframe_data);
-      return;
+      asection *sec = bfd_get_section_by_name (abfd, sect_name);
+      if (sec == NULL)
+	{
+	  printf (_("No %s section present\n\n"), sanitize_string (sect_name));
+	  return;
+	}
     }
-
-  printf (_("Contents of the SFrame section %s:"),
-	  sanitize_string (sect_name));
-  /* Dump the contents as text.  */
-  dump_sframe (sfd_ctx, sf_vma);
-
-  sframe_decoder_free (&sfd_ctx);
-  free (sframe_data);
+  dump_dwarf (abfd, is_mainfile);
 }
 
 
@@ -5840,7 +5816,7 @@  dump_bfd (bfd *abfd, bool is_mainfile)
 	dump_ctf (abfd, dump_ctf_section_name, dump_ctf_parent_name,
 		  dump_ctf_parent_section_name);
       if (dump_sframe_section_info)
-	dump_section_sframe (abfd, dump_sframe_section_name);
+	dump_sframe_section (abfd, dump_sframe_section_name, is_mainfile);
       if (dump_stab_section_info)
 	dump_stabs (abfd);
       if (dump_reloc_info && ! disassemble)
@@ -6304,7 +6280,9 @@  main (int argc, char **argv)
 	  seenflag = true;
 	  if (optarg)
 	    {
-	      if (dwarf_select_sections_by_names (optarg))
+	      if (strcmp (optarg, "sframe-internal-only") == 0)
+		warn (_("Unrecognized debug option 'sframe-internal-only'\n"));
+	      else if (dwarf_select_sections_by_names (optarg))
 		dump_dwarf_section_info = true;
 	    }
 	  else
@@ -6345,8 +6323,15 @@  main (int argc, char **argv)
 #endif
 	case OPTION_SFRAME:
 	  dump_sframe_section_info = true;
+
 	  if (optarg)
 	    dump_sframe_section_name = xstrdup (optarg);
+
+	  /* Error checking for user-provided section name is done in
+	     dump_sframe_section ().  Initialize for now with the default
+	     internal name: "sframe-internal-only".  */
+	  dwarf_select_sections_by_names ("sframe-internal-only");
+
 	  seenflag = true;
 	  break;
 	case 'G':
diff --git a/binutils/readelf.c b/binutils/readelf.c
index dd1871d8c75..e902c744177 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -6538,6 +6538,8 @@  parse_args (struct dump_data *dumpdata, int argc, char ** argv)
 	      dump_any_debugging = true;
 	      dwarf_select_sections_all ();
 	    }
+	  else if (strcmp (optarg, "sframe-internal-only") == 0)
+	    warn (_("Unrecognized debug option 'sframe-internal-only'\n"));
 	  else
 	    {
 	      do_debugging = false;
@@ -6583,9 +6585,15 @@  parse_args (struct dump_data *dumpdata, int argc, char ** argv)
 	  break;
 	case OPTION_SFRAME_DUMP:
 	  do_sframe = true;
+	  /* Fix PR/32589 but keep the error messaging same ?  */
+	  if (optarg != NULL && strcmp (optarg, "") == 0)
+	    {
+	      do_dump = true;
+	      error (_("Section name must be provided\n"));
+	    }
 	  /* Providing section name is optional.  request_dump (), however,
 	     thrives on non NULL optarg.  Handle it explicitly here.  */
-	  if (optarg != NULL)
+	  else if (optarg != NULL)
 	    request_dump (dumpdata, SFRAME_DUMP);
 	  else
 	    {
@@ -17101,44 +17109,6 @@  dump_section_as_ctf (Elf_Internal_Shdr * section, Filedata * filedata)
 }
 #endif
 
-static bool
-dump_section_as_sframe (Elf_Internal_Shdr * section, Filedata * filedata)
-{
-  void *		  data = NULL;
-  sframe_decoder_ctx	  *sfd_ctx = NULL;
-  const char *print_name = printable_section_name (filedata, section);
-
-  bool ret = true;
-  size_t sf_size;
-  int err = 0;
-
-  if (strcmp (print_name, "") == 0)
-    {
-      error (_("Section name must be provided \n"));
-      ret = false;
-      return ret;
-    }
-
-  data = get_section_contents (section, filedata);
-  sf_size = section->sh_size;
-  /* Decode the contents of the section.  */
-  sfd_ctx = sframe_decode ((const char*)data, sf_size, &err);
-  if (!sfd_ctx)
-    {
-      ret = false;
-      error (_("SFrame decode failure: %s\n"), sframe_errmsg (err));
-      goto fail;
-    }
-
-  printf (_("Contents of the SFrame section %s:"), print_name);
-  /* Dump the contents as text.  */
-  dump_sframe (sfd_ctx, section->sh_addr);
-
- fail:
-  free (data);
-  return ret;
-}
-
 static bool
 load_specific_debug_section (enum dwarf_section_display_enum  debug,
 			     const Elf_Internal_Shdr *        sec,
@@ -17706,7 +17676,7 @@  process_section_contents (Filedata * filedata)
 #endif
       if (dump & SFRAME_DUMP)
 	{
-	  if (! dump_section_as_sframe (section, filedata))
+	  if (! display_debug_section (i, section, filedata))
 	    res = false;
 	}
     }
diff --git a/gas/testsuite/gas/cfi-sframe/cfi-sframe-aarch64-pac-ab-key-1.d b/gas/testsuite/gas/cfi-sframe/cfi-sframe-aarch64-pac-ab-key-1.d
index 599d4c4e795..7e3fd8ab622 100644
--- a/gas/testsuite/gas/cfi-sframe/cfi-sframe-aarch64-pac-ab-key-1.d
+++ b/gas/testsuite/gas/cfi-sframe/cfi-sframe-aarch64-pac-ab-key-1.d
@@ -18,10 +18,10 @@  Contents of the SFrame section .sframe:
     0+0004 +sp\+0 +u +u\[s\] +
     0+0008 +sp\+16 +c-16 +c-8\[s\] +
 
-    func idx \[1\]: pc = 0x0, size = 20 bytes, pauth = B key
+    func idx \[1\]: pc = 0xc, size = 20 bytes, pauth = B key
     STARTPC + CFA + FP +  RA +
-    0+0000 +sp\+0 +u +u +
-    0+0004 +sp\+0 +u +u\[s\] +
-    0+0008 +sp\+16 +c-16 +c-8\[s\] +
+    0+000c +sp\+0 +u +u +
+    0+0010 +sp\+0 +u +u\[s\] +
+    0+0014 +sp\+16 +c-16 +c-8\[s\] +
 
 #pass