Re: RFC: Objcopy --only-keep-debug update

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Fri, Aug 7, 2015 at 8:56 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Tue, Aug 4, 2015 at 3:48 AM, Nick Clifton <nickc@redhat.com> wrote:
>> Hi Guys,
>>
>>   Thanks for the comments on the previous patch.  I am attaching a third
>>   iteration of this patch, which I hope will satisfy everyone.  In this
>>   version I have followed Alan's suggestion of detecting the change in
>>   the _bfd_elf_copy_private_bfd_data function, and I have fixed the text
>>   in binutils.texi describing how --only-keep-debug operates.
>>
>>   Any more comments or suggestions ?
>>
>> Cheers
>>   Nick
>>
>> bfd/ChangeLog
>> 2015-08-04  Nick Clifton  <nickc@redhat.com>
>>
>>         * elf.c (_bfd_elf_copy_private_bfd_data): Copy the sh_link and
>>         sh_info fields of sections whose type has been changed to
>>         SHT_NOBITS.
>>
>> binutils/ChangeLog
>> 2015-08-04  Nick Clifton  <nickc@redhat.com>
>>
>>         * doc/binutils.texi: Document that the --only-keep-debug option
>>         to strip and objcopy preserves the section headers of stripped
>>         sections.
>>
>> binutils/testsuite/ChangeLog
>> 2015-08-04  Nick Clifton  <nickc@redhat.com>
>>
>>         * binutils-all/objcopy.exp (keep_debug_symbols_and_check_links):
>>         New proc.  Checks that debug-info-only binaries retain the
>>         sh_link field in stripped sections.
>>
>
> This breaks binutils:
>
> https://sourceware.org/bugzilla/show_bug.cgi?id=18785
>

I checked in this patch to fix it.

-- 
H.J.
---
When copying the sh_link and sh_info fields in stripped section headers,
we also check if the sh_type, sh_flags, /sh_addralign and sh_entsize
fields of the output section match the output.  Since --only-keep-debug
turns all non-debug sections into SHT_NOBITS sections, the output
SHT_NOBITS type matches any input type.

bfd/

PR binutils/18785
* elf.c (_bfd_elf_copy_private_bfd_data): When copying the
sh_link and sh_info fields in stripped section headers, we also
check if the sh_type, sh_flags, /sh_addralign and sh_entsize
fields of the output section match the output.  Since
--only-keep-debug turns all non-debug sections into SHT_NOBITS
sections, the output SHT_NOBITS type matches any input type.

binutils/testsuite/

PR binutils/18785
* binutils-all/objcopy.exp: Run strip-12.
* binutils-all/strip-12.d: New file.
* binutils-all/strip-12.s: Likewise.
-

From 115b1941bf2bd062e3f2372a475639a12a3da1a1 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Fri, 7 Aug 2015 10:28:42 -0700
Subject: [PATCH] Check sh_type/sh_flags/sh_addralign/sh_entsize when copying
 sh_link/sh_info

When copying the sh_link and sh_info fields in stripped section headers,
we also check if the sh_type, sh_flags, /sh_addralign and sh_entsize
fields of the output section match the output.  Since --only-keep-debug
turns all non-debug sections into SHT_NOBITS sections, the output
SHT_NOBITS type matches any input type.

bfd/

	PR binutils/18785
	* elf.c (_bfd_elf_copy_private_bfd_data): When copying the
	sh_link and sh_info fields in stripped section headers, we also
	check if the sh_type, sh_flags, /sh_addralign and sh_entsize
	fields of the output section match the output.  Since
	--only-keep-debug turns all non-debug sections into SHT_NOBITS
	sections, the output SHT_NOBITS type matches any input type.

binutils/testsuite/

	PR binutils/18785
	* binutils-all/objcopy.exp: Run strip-12.
	* binutils-all/strip-12.d: New file.
	* binutils-all/strip-12.s: Likewise.
---
 bfd/elf.c                                   | 9 ++++++++-
 binutils/testsuite/binutils-all/objcopy.exp | 1 +
 binutils/testsuite/binutils-all/strip-12.d  | 7 +++++++
 binutils/testsuite/binutils-all/strip-12.s  | 6 ++++++
 4 files changed, 22 insertions(+), 1 deletion(-)
 create mode 100644 binutils/testsuite/binutils-all/strip-12.d
 create mode 100644 binutils/testsuite/binutils-all/strip-12.s

diff --git a/bfd/elf.c b/bfd/elf.c
index 67e4240..9e401c8 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -1233,7 +1233,14 @@ _bfd_elf_copy_private_bfd_data (bfd *ibfd, bfd *obfd)
 	    {
 	      Elf_Internal_Shdr * iheader = iheaders[j];
 	      
-	      if (iheader->sh_type != SHT_NOBITS
+	      /* Since --only-keep-debug turns all non-debug sections
+		 into SHT_NOBITS sections, the output SHT_NOBITS type
+		 matches any input type.  */
+	      if ((oheader->sh_type == SHT_NOBITS
+		   || oheader->sh_type == oheader->sh_type)
+		  && iheader->sh_flags == oheader->sh_flags
+		  && iheader->sh_addralign == oheader->sh_addralign
+		  && iheader->sh_entsize == oheader->sh_entsize
 		  && iheader->sh_size == oheader->sh_size
 		  && iheader->sh_addr == oheader->sh_addr
 		  && (iheader->sh_info != oheader->sh_info
diff --git a/binutils/testsuite/binutils-all/objcopy.exp b/binutils/testsuite/binutils-all/objcopy.exp
index 75514e4..cb8e33b 100644
--- a/binutils/testsuite/binutils-all/objcopy.exp
+++ b/binutils/testsuite/binutils-all/objcopy.exp
@@ -1033,6 +1033,7 @@ if [is_elf_format] {
     run_dump_test "strip-7"
     run_dump_test "strip-8"
     run_dump_test "strip-9"
+    run_dump_test "strip-12"
     # Non-EABI ARM targets will set OSABI to ARM
     # The V850 sets the OSABI to UNIX - System V
     if { ![istarget "*-*-hpux*"]
diff --git a/binutils/testsuite/binutils-all/strip-12.d b/binutils/testsuite/binutils-all/strip-12.d
new file mode 100644
index 0000000..a33faab
--- /dev/null
+++ b/binutils/testsuite/binutils-all/strip-12.d
@@ -0,0 +1,7 @@
+#PROG: strip
+#strip:
+#readelf: -S --wide
+
+#...
+  \[[ 0-9]+\] \.bss[ \t]+NOBITS[ \t0-9a-f]+WA[ \t]+0[ \t]+0[ \t]+1
+#pass
diff --git a/binutils/testsuite/binutils-all/strip-12.s b/binutils/testsuite/binutils-all/strip-12.s
new file mode 100644
index 0000000..46b729f
--- /dev/null
+++ b/binutils/testsuite/binutils-all/strip-12.s
@@ -0,0 +1,6 @@
+	.bss
+	.space 8
+	.section	.debug_str,"MS",%progbits,1
+	.string	""
+	.section        .text.foo,"axG",%progbits,foo,comdat
+	.byte 0
-- 
2.4.3