[PATCH] nm: Remove --with-symbol-versions

Fangrui Song i@maskray.me
Thu Aug 13 02:42:02 GMT 2020


"bfd: Display symbol version for nm -D" has a minor problem: an
undefined symbol (e.g. strlen@GLIBC_2.2.5 in cat) should use one @,
instead of two @@. nm -D output is currently inconsistent with readelf -Ws's
output and ld -y's behavior.

On 2020-08-07, H.J. Lu via Binutils wrote:
>Since
>
>commit 7e6e972f74aeac0ebdbd95a7f905d871cd2581de
>Author: H.J. Lu <hjl.tools@gmail.com>
>Date:   Tue Mar 24 04:23:11 2020 -0700
>
>    bfd: Display symbol version for nm -D
>
>always displays symbol version for nm, remove --with-symbol-versions and
>silently accept it for backward compatibility.
>
>binutils/
>
>	PR binutils/26302
>	* nm.c (with_symbol_versions): Removed.
>	(long_option_values): Add OPTION_WITH_SYMBOL_VERSIONS.
>	(long_options): Update --with-symbol-versions entry.
>	(print_symbol): Remove the with_symbol_versions check.
>	(main): Add OPTION_WITH_SYMBOL_VERSIONS for backward
>	compatibility.
>	* doc/binutils.texi: Remove --with-symbol-versions.
>
>ld/
>
>	PR binutils/26302
>	* testsuite/ld-elf/pr26302.nd: New file.
>	* testsuite/ld-elf/pr26302.ver: Likewise.
>	* testsuite/ld-elf/pr26302a.c: Likewise.
>	* testsuite/ld-elf/pr26302b.c: Likewise.
>	* testsuite/ld-elf/shared.exp: Run binutils/26302 tests.
>---
> binutils/doc/binutils.texi      | 10 +---------
> binutils/nm.c                   | 26 +++++++-------------------
> ld/testsuite/ld-elf/pr26302.nd  |  3 +++
> ld/testsuite/ld-elf/pr26302.ver |  5 +++++
> ld/testsuite/ld-elf/pr26302a.c  |  4 ++++
> ld/testsuite/ld-elf/pr26302b.c  |  7 +++++++
> ld/testsuite/ld-elf/shared.exp  | 18 ++++++++++++++++++
> 7 files changed, 45 insertions(+), 28 deletions(-)
> create mode 100644 ld/testsuite/ld-elf/pr26302.nd
> create mode 100644 ld/testsuite/ld-elf/pr26302.ver
> create mode 100644 ld/testsuite/ld-elf/pr26302a.c
> create mode 100644 ld/testsuite/ld-elf/pr26302b.c
>
>diff --git a/binutils/doc/binutils.texi b/binutils/doc/binutils.texi
>index 4a11bf1f1a..0822b5c8b3 100644
>--- a/binutils/doc/binutils.texi
>+++ b/binutils/doc/binutils.texi
>@@ -796,7 +796,7 @@ nm [@option{-A}|@option{-o}|@option{--print-file-name}] [@option{-a}|@option{--d
>    [@option{--plugin} @var{name}]
>    [@option{--no-recurse-limit}|@option{--recurse-limit}]]
>    [@option{--size-sort}] [@option{--special-syms}]
>-   [@option{--synthetic}] [@option{--with-symbol-versions}] [@option{--target=}@var{bfdname}]
>+   [@option{--synthetic}] [@option{--target=}@var{bfdname}]
>    [@var{objfile}@dots{}]
> @c man end
> @end smallexample
>@@ -1130,14 +1130,6 @@ Include synthetic symbols in the output.  These are special symbols
> created by the linker for various purposes.  They are not shown by
> default since they are not part of the binary's original source code.
>
>-@item --with-symbol-versions
>-Enables the display of symbol version information if any exists.  The
>-version string is displayed as a suffix to the symbol name, preceded by
>-an @@ character.  For example @samp{foo@@VER_1}.  If the version is
>-the default version to be used when resolving unversioned references
>-to the symbol then it is displayed as a suffix preceded by two @@
>-characters.  For example @samp{foo@@@@VER_2}.
>-
> @item --target=@var{bfdname}
> @cindex object code format
> Specify an object code format other than your system's default format.
>diff --git a/binutils/nm.c b/binutils/nm.c
>index 1b5122d56a..69e697ae92 100644
>--- a/binutils/nm.c
>+++ b/binutils/nm.c
>@@ -161,7 +161,6 @@ static int show_version = 0;	/* Show the version number.  */
> static int show_synthetic = 0;	/* Display synthesized symbols too.  */
> static int line_numbers = 0;	/* Print line numbers for symbols.  */
> static int allow_special_symbols = 0;  /* Allow special symbols.  */
>-static int with_symbol_versions = 0; /* Include symbol version information in the output.  */
>
> static int demangle_flags = DMGL_ANSI | DMGL_PARAMS;
>
>@@ -192,7 +191,8 @@ enum long_option_values
>   OPTION_PLUGIN,
>   OPTION_SIZE_SORT,
>   OPTION_RECURSE_LIMIT,
>-  OPTION_NO_RECURSE_LIMIT
>+  OPTION_NO_RECURSE_LIMIT,
>+  OPTION_WITH_SYMBOL_VERSIONS
> };
>
> static struct option long_options[] =
>@@ -226,7 +226,8 @@ static struct option long_options[] =
>   {"defined-only", no_argument, &defined_only, 1},
>   {"undefined-only", no_argument, &undefined_only, 1},
>   {"version", no_argument, &show_version, 1},
>-  {"with-symbol-versions", no_argument, &with_symbol_versions, 1},
>+  {"with-symbol-versions", no_argument, NULL,
>+   OPTION_WITH_SYMBOL_VERSIONS},
>   {0, no_argument, 0, 0}
> };
> 
>@@ -901,22 +902,6 @@ print_symbol (bfd *        abfd,
>
>   format->print_symbol_info (&info, abfd);
>
>-  if (with_symbol_versions)
>-    {
>-      const char *  version_string = NULL;
>-      bfd_boolean   hidden = FALSE;
>-
>-      if ((sym->flags & (BSF_SECTION_SYM | BSF_SYNTHETIC)) == 0)
>-	version_string = bfd_get_symbol_version_string (abfd, sym,
>-							TRUE, &hidden);
>-
>-      if (bfd_is_und_section (bfd_asymbol_section (sym)))
>-	hidden = TRUE;
>-
>-      if (version_string && *version_string != '\0')
>-	printf (hidden ? "@%s" : "@@%s", version_string);
>-    }
>-
>   if (line_numbers)
>     {
>       static asymbol **syms;
>@@ -1761,6 +1746,9 @@ main (int argc, char **argv)
> 	case OPTION_NO_RECURSE_LIMIT:
> 	  demangle_flags |= DMGL_NO_RECURSE_LIMIT;
> 	  break;
>+	case OPTION_WITH_SYMBOL_VERSIONS:
>+	  /* Ignored for backward compatibility.  */
>+	  break;
> 	case 'D':
> 	  dynamic = 1;
> 	  break;
>diff --git a/ld/testsuite/ld-elf/pr26302.nd b/ld/testsuite/ld-elf/pr26302.nd
>new file mode 100644
>index 0000000000..1f2fbdf9a3
>--- /dev/null
>+++ b/ld/testsuite/ld-elf/pr26302.nd
>@@ -0,0 +1,3 @@
>+#...
>+ +U foo@@FOO
>+#pass
>diff --git a/ld/testsuite/ld-elf/pr26302.ver b/ld/testsuite/ld-elf/pr26302.ver
>new file mode 100644
>index 0000000000..f2c03ac7a1
>--- /dev/null
>+++ b/ld/testsuite/ld-elf/pr26302.ver
>@@ -0,0 +1,5 @@
>+FOO
>+{
>+global:
>+  foo;
>+};
>diff --git a/ld/testsuite/ld-elf/pr26302a.c b/ld/testsuite/ld-elf/pr26302a.c
>new file mode 100644
>index 0000000000..cd0130cacd
>--- /dev/null
>+++ b/ld/testsuite/ld-elf/pr26302a.c
>@@ -0,0 +1,4 @@
>+void
>+foo (void)
>+{
>+}
>diff --git a/ld/testsuite/ld-elf/pr26302b.c b/ld/testsuite/ld-elf/pr26302b.c
>new file mode 100644
>index 0000000000..eae278df96
>--- /dev/null
>+++ b/ld/testsuite/ld-elf/pr26302b.c
>@@ -0,0 +1,7 @@
>+extern void foo (void);
>+
>+void
>+bar (void)
>+{
>+  foo ();
>+}
>diff --git a/ld/testsuite/ld-elf/shared.exp b/ld/testsuite/ld-elf/shared.exp
>index e9e9012058..014937175f 100644
>--- a/ld/testsuite/ld-elf/shared.exp
>+++ b/ld/testsuite/ld-elf/shared.exp
>@@ -843,6 +843,24 @@ run_cc_link_tests [list \
> 	{{readelf {--dyn-syms --wide} pr26094-1b.rd}} \
> 	"pr26094-1" \
>     ] \
>+    [list \
>+	"Build pr26302a.so" \
>+	"-shared -Wl,--version-script=pr26302.ver" \
>+	"-fPIC" \
>+	{pr26302a.c} \
>+	{} \
>+	"pr26302a.so"
>+    ] \
>+    [list \
>+	"Build pr26302b.so" \
>+	"-shared -Wl,--no-as-needed tmpdir/pr26302a.so" \
>+	"-fPIC" \
>+	{pr26302b.c} \
>+	{{nm {-u} pr26302.nd} \
>+	 {nm {-u -D} pr26302.nd} \
>+	 {nm {-u -D --with-symbol-versions} pr26302.nd}} \
>+	"pr26302b.so" \
>+    ] \
> ]
>
> run_ld_link_tests [list \
>-- 
>2.26.2
>


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