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Re: [PATCH] PR gas/21661: Check unsupported .symver with common symbol

From: Renlin Li <renlin dot li at foss dot arm dot com>
To: "H.J. Lu" <hjl dot tools at gmail dot com>, binutils at sourceware dot org
Date: Tue, 27 Jun 2017 17:03:02 +0100
Subject: Re: [PATCH] PR gas/21661: Check unsupported .symver with common symbol
Authentication-results: sourceware.org; auth=none
References: <20170623135201.GA2302@gmail.com> <20170626120915.GA23351@gmail.com>

Hi H.J.,

This patch breaks aarch64/arm linux toolchain in cross build environment.

I have got the following error message:

/tmpdir/ccQfHyoF.s: Assembler messages:
/tmpdir/ccQfHyoF.s: Error: `loc1@GLIBC_2.4' can't be versioned to common symbol 'loc1'
/tmpdir/ccQfHyoF.s: Error: `loc2@GLIBC_2.4' can't be versioned to common symbol 'loc2'
/tmpdir/ccQfHyoF.s: Error: `locs@GLIBC_2.4' can't be versioned to common symbol 'locs'
make[2]: *** [/tmpdir/build-arm-none-linux-gnueabi/obj/glibc/misc/regexp.os] Error 1

in glibc, I saw the following code in glibc/misc/regexp.c which generate .symver directivefor each variable.


compat_symbol (libc, loc1, loc1, GLIBC_2_0);
compat_symbol (libc, loc2, loc2, GLIBC_2_0);
compat_symbol (libc, locs, locs, GLIBC_2_0);


Regards,
Renlin


On 26/06/17 13:09, H.J. Lu wrote:

On Fri, Jun 23, 2017 at 06:52:01AM -0700, H.J. Lu wrote:

The .symver directive on common symbol creates a new common symbol,
which shouldn't be allowed, similar to alias on common symbol:

$ cat y.S
	.comm	bar,8,8
	 .set bar1,bar
$ as -o y.o y.S
y.S: Assembler messages:
y.S:2: Error: `bar1' can't be equated to common symbol 'bar'
$

OK for master?

H.J.
---
	PR gas/21661
	* config/obj-elf.c (obj_elf_symver): Don't allow .symver with
	common symbol.
	(elf_frob_symbol): Likewise.
	* testsuite/gas/elf/elf.exp: Run pr21661.
	* testsuite/gas/elf/pr21661.d: New file.
	* testsuite/gas/elf/pr21661.s: Likewise.


This is what I checked in.


H.J.
---
The .symver directive on common symbol creates a new common symbol,
which shouldn't be allowed, similar to alias on common symbol:

$ cat y.S
	.comm	bar,8,8
	 .set bar1,bar
$ as -o y.o y.S
y.S: Assembler messages:
y.S:2: Error: `bar1' can't be equated to common symbol 'bar'
$

	PR gas/21661
	* config/obj-elf.c (obj_elf_symver): Don't allow .symver with
	common symbol.
	(elf_frob_symbol): Likewise.
	* testsuite/gas/elf/elf.exp: Run pr21661.
	* testsuite/gas/elf/pr21661.d: New file.
	* testsuite/gas/elf/pr21661.s: Likewise.
---
  gas/config/obj-elf.c            | 15 +++++++++++++++
  gas/testsuite/gas/elf/elf.exp   |  1 +
  gas/testsuite/gas/elf/pr21661.d |  2 ++
  gas/testsuite/gas/elf/pr21661.l |  3 +++
  gas/testsuite/gas/elf/pr21661.s |  4 ++++
  5 files changed, 25 insertions(+)
  create mode 100644 gas/testsuite/gas/elf/pr21661.d
  create mode 100644 gas/testsuite/gas/elf/pr21661.l
  create mode 100644 gas/testsuite/gas/elf/pr21661.s

diff --git a/gas/config/obj-elf.c b/gas/config/obj-elf.c
index 3696d5e..49d99a4 100644
--- a/gas/config/obj-elf.c
+++ b/gas/config/obj-elf.c
@@ -1414,6 +1414,14 @@ obj_elf_symver (int ignore ATTRIBUTE_UNUSED)
    c = get_symbol_name (& name);
    lex_type[(unsigned char) '@'] = old_lexat;

+  if (S_IS_COMMON (sym))
+    {
+      as_bad (_("`%s' can't be versioned to common symbol '%s'"),
+	      name, S_GET_NAME (sym));
+      ignore_rest_of_line ();
+      return;
+    }
+
    if (symbol_get_obj (sym)->versioned_name == NULL)
      {
        symbol_get_obj (sym)->versioned_name = xstrdup (name);
@@ -2277,6 +2285,13 @@ elf_frob_symbol (symbolS *symp, int *puntp)
  	      symp2 = symbol_find_or_make (sy_obj->versioned_name);

  	      /* Now we act as though we saw symp2 = sym.  */
+	      if (S_IS_COMMON (symp))
+		{
+		  as_bad (_("`%s' can't be versioned to common symbol '%s'"),
+			  sy_obj->versioned_name, S_GET_NAME (symp));
+		  *puntp = TRUE;
+		  return;
+		}

  	      S_SET_SEGMENT (symp2, S_GET_SEGMENT (symp));

diff --git a/gas/testsuite/gas/elf/elf.exp b/gas/testsuite/gas/elf/elf.exp
index ad38d66..6b2b31a 100644
--- a/gas/testsuite/gas/elf/elf.exp
+++ b/gas/testsuite/gas/elf/elf.exp
@@ -184,6 +184,7 @@ if { [is_elf_format] } then {
  	run_dump_test "symtab"
      }
      run_dump_test "symver"
+    run_dump_test "pr21661"

      # No indirect functions on non-GNU targets.
      # The Visium and MSP set the ELF header's OSABI field to ELFOSABI_STANDALONE.
diff --git a/gas/testsuite/gas/elf/pr21661.d b/gas/testsuite/gas/elf/pr21661.d
new file mode 100644
index 0000000..a16e410
--- /dev/null
+++ b/gas/testsuite/gas/elf/pr21661.d
@@ -0,0 +1,2 @@
+#name: unsupported .symver with common symbol
+#error-output: pr21661.l
diff --git a/gas/testsuite/gas/elf/pr21661.l b/gas/testsuite/gas/elf/pr21661.l
new file mode 100644
index 0000000..0565faa
--- /dev/null
+++ b/gas/testsuite/gas/elf/pr21661.l
@@ -0,0 +1,3 @@
+[^:]*: Assembler messages:
+[^:]*:2: Error: `foo@VERS.1' can't be versioned to common symbol 'foo'
+[^:]*: Error: `bar@VERS.1' can't be versioned to common symbol 'bar'
diff --git a/gas/testsuite/gas/elf/pr21661.s b/gas/testsuite/gas/elf/pr21661.s
new file mode 100644
index 0000000..5586bfd
--- /dev/null
+++ b/gas/testsuite/gas/elf/pr21661.s
@@ -0,0 +1,4 @@
+	.comm	foo,8,8
+	 .symver foo,foo@VERS.1
+	 .symver bar,bar@VERS.1
+	.comm	bar,8,8

Follow-Ups:
- Re: [PATCH] PR gas/21661: Check unsupported .symver with common symbol
  - From: H.J. Lu

References:
- [PATCH] PR gas/21661: Check unsupported .symver with common symbol
  - From: H.J. Lu
- Re: [PATCH] PR gas/21661: Check unsupported .symver with common symbol
  - From: H.J. Lu

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