PATCH: PR ld/12356: [Regression] x86_64 kernel failed to link

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

On Mon, Dec 27, 2010 at 8:17 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Mon, Dec 20, 2010 at 4:59 AM, Alan Modra <amodra@gmail.com> wrote:
>> On Fri, Dec 17, 2010 at 11:41:40AM -0800, H.J. Lu wrote:
>>> The updated patch with a new testcase.
>>
>> I think this is a better solution, works on current binutils testsuite,
>> the testcases in PR12066, and on kernel builds I tried. ?You can
>> even describe linker behaviour without too much embarassment.
>>
>> I added an option to allow people to experiment with a consistent
>> linker expression resolver by setting
>> ?__ld_compatibility = 221 ;
>> somewhere in their linker scripts. ?This treats numbers and absolute
>> symbols as numbers everywhere, the most flexible arrangement since
>> you can force a number to be an absolute address by using ABSOLUTE(),
>> but you can't do the reverse.
>>
>> ? ? ? ?* ld.texinfo (Expression Section): Describe treatment of numbers
>> ? ? ? ?and absolute symbols.
>> ? ? ? ?* ldemul.c (after_open_default): Look up __ld_compatibility.
>> ? ? ? ?* ldexp.c (fold_name): Convert absolute symbols to numbers when
>> ? ? ? ?inside output section definitions, or when __ld_compatibility >= 221.
>> ? ? ? ?(exp_fold_tree_1): Convert numbers to absolute when not in output
>> ? ? ? ?section definition and __ld_compatibility < 221. ?Don't always
>> ? ? ? ?convert values outside an output section definition to absolute.
>> ? ? ? ?* ldexp.h (uses_defined): Comment.
>> ? ? ? ?* ldlang.c (ld_compatibility): New variable.
>> ? ? ? ?* ldlang.h (ld_compatibility): Declare.
>> ? ? ? ?* emultempl/aix.em, * emultempl/armcoff.em, * emultempl/beos.em,
>> ? ? ? ?* emultempl/elf32.em, * emultempl/genelf.em, * emultempl/lnk960.em,
>> ? ? ? ?* emultempl/m68kcoff.em, * emultempl/mmo.em, * emultempl/pe.em,
>> ? ? ? ?* emultempl/pep.em, * emultempl/sunos.em, * emultempl/z80.em: Call
>> ? ? ? ?after_open_default from after_open function.
>>
>
> I am not sure how useful "__ld_compatibility" will be. I don't think we
> should change the behaviors of known linker scripts. Those failure
> caused by changing behaviors of linker scripts may be hard to debug.
> In some cases, changing linker scripts, which have been used for
> years, may not be a viable option.
>
>

__ld_compatibility was added without any testcases and its prerequisite
caused PR ld/12356. I am checking this patch into the next Linux binutils
to fix PR ld/12356.

-- 
H.J.
---
ld/

2011-01-01  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/12356
	Revert 2011-12-20 by Alan Modra <amodra@gmail.com>.
	* ld.texinfo (Expression Section): Remove __ld_compatibility.

	* ldemul.c (after_open_default): Don't check  __ld_compatibility.
	* ldexp.c (fold_name): Likewise.
	(exp_fold_tree_1): Likewise.

	* ldlang.c (ld_compatibility): Removed.
	* ldlang.h (ld_compatibility): Likewise.

	* emultempl/aix.em (gld${EMULATION_NAME}_after_open): Don't call
	after_open_default.
	* emultempl/armcoff.em (gld${EMULATION_NAME}_after_open): Likewise.
	* emultempl/beos.em (gld${EMULATION_NAME}_after_open): Likewise.
	* emultempl/elf32.em (gld${EMULATION_NAME}_after_open): Likewise.
	* emultempl/genelf.em (gld${EMULATION_NAME}_after_open): Likewise.
	* emultempl/lnk960.em (gld${EMULATION_NAME}_after_open): Likewise.
	* emultempl/m68kcoff.em (gld${EMULATION_NAME}_after_open): Likewise.
	* emultempl/mmo.em (gld${EMULATION_NAME}_after_open): Likewise.
	* emultempl/pe.em (gld${EMULATION_NAME}_after_open): Likewise.
	* emultempl/pep.em (gld${EMULATION_NAME}_after_open): Likewise.
	* emultempl/sunos.em (gld${EMULATION_NAME}_after_open): Likewise.
	* emultempl/z80.em (gld${EMULATION_NAME}_after_open): Likewise.

2011-01-01  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/12356
	* ldlang.c: Revert 2011-12-20 by Alan Modra <amodra@gmail.com>.
	* ldexp.h: Likewise.
	* ldexp.c: Likewise.
	* ldlang.c: Likewise.

ld/testsuite/

2011-01-01  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/12356
	* ld-scripts/default-script2.d: Revert 2011-12-20 by Alan
	Modra <amodra@gmail.com>.

	* ld-scripts/defined5.d: New.
	* ld-scripts/defined5.s: Likewise.
	* ld-scripts/defined5.t: Likewise.

	* ld-scripts/defined.exp: Run defined5.

Attachment: binutils-pr12356-1.patch
Description: Text document