[PATCH] nm: fix treating an ifunc symbol as a stab if '--ifunc-chars=--' is given

[Dmitry Klochkov]

If an ifunc symbol is processed in print_symbol(), a 'type' field of a
'syminfo' structure is set to any character specified by a user with an
'--ifunc-chars' option.  But afterwards the 'type' field is used to
check whether a symbol is a stab in print_symbol_info_{bsd,sysv}()
functions in order to print additional stab related data.  If the 'type'
field equals '-', a symbol is treated as a stab.  If '--ifunc-chars=--'
is given, all ifunc symbols will be treated as stab symbols and
uninitialized stab related fields of the 'syminfo' structure will be
printed which can lead to segmentation fault.

To fix this, check if a symbol is a stab before override the 'type'
field.  Also, add a test case for this fix.

	PR binutils/32556
	* nm.c (extended_symbol_info): Add is_stab.
	(print_symbol): Check if a symbol is a stab.
	(print_symbol_info_bsd): Use info->is_stab.
	(print_symbol_info_sysv): Use info->is_stab.
	* testsuite/binutils-all/nm.exp: Test nm --ifunc-chars=--.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=32556
Fixes: e6f6aa8d184 ("Add option to nm to change the characters displayed for ifunc symbols")
Signed-off-by: Dmitry Klochkov <dmitry.klochkov@bell-sw.com>
---
 binutils/nm.c                          | 10 +++++++---
 binutils/testsuite/binutils-all/nm.exp |  9 +++++++++
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/binutils/nm.c b/binutils/nm.c
index dce9207f44f..c3d118a93c3 100644
--- a/binutils/nm.c
+++ b/binutils/nm.c
@@ -70,6 +70,7 @@ struct extended_symbol_info
   bfd_vma ssize;
   elf_symbol_type *elfinfo;
   coff_symbol_type *coffinfo;
+  bool is_stab;
   /* FIXME: We should add more fields for Type, Line, Section.  */
 };
 #define SYM_VALUE(sym)       (sym->sinfo->value)
@@ -1208,8 +1209,11 @@ print_symbol (bfd *        abfd,
 
   bfd_get_symbol_info (abfd, sym, &syminfo);
 
+  info.is_stab = false;
+  if (syminfo.type == '-')
+    info.is_stab = true;
   /* PR 22967 - Distinguish between local and global ifunc symbols.  */
-  if (syminfo.type == 'i'
+  else if (syminfo.type == 'i'
       && sym->flags & BSF_GNU_INDIRECT_FUNCTION)
     {
       if (ifunc_type_chars == NULL || ifunc_type_chars[0] == 0)
@@ -1873,7 +1877,7 @@ print_symbol_info_bsd (struct extended_symbol_info *info, bfd *abfd)
 
   printf (" %c", SYM_TYPE (info));
 
-  if (SYM_TYPE (info) == '-')
+  if (info->is_stab)
     {
       /* A stab.  */
       printf (" ");
@@ -1902,7 +1906,7 @@ print_symbol_info_sysv (struct extended_symbol_info *info, bfd *abfd)
 
   printf ("|   %c  |", SYM_TYPE (info));
 
-  if (SYM_TYPE (info) == '-')
+  if (info->is_stab)
     {
       /* A stab.  */
       printf ("%18s|  ", SYM_STAB_NAME (info));		/* (C) Type.  */
diff --git a/binutils/testsuite/binutils-all/nm.exp b/binutils/testsuite/binutils-all/nm.exp
index fea68bf76bc..5a7c5d614d3 100644
--- a/binutils/testsuite/binutils-all/nm.exp
+++ b/binutils/testsuite/binutils-all/nm.exp
@@ -329,6 +329,15 @@ if [is_elf_format] {
 	    fail "$testname (local ifunc)"
 	}
 
+	# PR 32556
+	# Test nm --ifunc-chars=--
+	set got [binutils_run $NM "$NMFLAGS --ifunc-chars=-- $tmpfile"]
+	if [regexp -- "- global_foo\n\[^-\]+- local_foo" $got] then {
+	    pass "$testname=--"
+	} else {
+	    fail "$testname=--"
+	}
+
 	if { $verbose < 1 } {
 	    remote_file host delete "tmpdir/ifunc.o"
 	}
-- 
2.49.0