[Bug ld/15904] New: ia64, ELF, 'Can't relax br (PCREL21B)' error message on --no-keep-memory

[address@hidden]

http://sourceware.org/bugzilla/show_bug.cgi?id=15904



            Bug ID: 15904

           Summary: ia64, ELF, 'Can't relax br (PCREL21B)' error message

                    on --no-keep-memory

           Product: binutils

           Version: 2.23

            Status: NEW

          Severity: normal

          Priority: P2

         Component: ld

          Assignee: unassigned at sourceware dot org

          Reporter: address@hidden



Created attachment 7174

  --> http://sourceware.org/bugzilla/attachment.cgi?id=7174&action=edit

A patch proposal for the bug.



Debian Linux on ia64 (Itanium), sid (unstable).



The binutils build is the Debian package binutils 2.23.52.20130727-1.



The build of the Iceweasel 17.0.8esr-1 package (a renamed Firefox) fails:



/«PKGBUILDDIR»/build-xulrunner/_virtualenv/bin/python

../../../config/pythonpath.py -I../../config ../../../config/expandlibs_exe
c.py

--depend .deps/libxul.so.pp --target libxul.so --uselist --  g++

-D_FORTIFY_SOURCE=2 -Wall -Wpointer-arith -Woverloaded-virtual

-Werror=return-type -Wtype-limits -Wempty-body -Wno-ctor-dtor-privacy

-Wno-overlength-strings -Wno-invalid-offsetof -Wno-variadic-macros -Wformat

-Werror=format-security -fno-exceptions -fno-strict-aliasing -fno-rtti

-ffunction-sections -fdata-sections -fno-exceptions -std=gnu++0x -pthread
 -pipe

 -DNDEBUG -DTRIMMED -g -O2 -fomit-frame-pointer -fPIC -shared -Wl,-z,defs

-Wl,--gc-sections -Wl,-h,libxul.so -o libxul.so  nsStaticXULComponents.o

nsUnicharUtils.o nsBidiUtils.o nsSpecialCasingData.o nsUnicodeProperties.o

nsRDFResource.o    -Wl,--as-needed -Wl,--no-keep-memory

-Wl,--reduce-memory-overheads -Wl,--stats -lpthread  -Wl,-z,noexecstack 
 

-Wl,-rpath-link,/«PKGBUILDDIR»/build-xulrunner/dist/bin

-Wl,-rpath-link,/usr/lib   ../../toolkit/components/osfile/libosfile_s.a

../../toolkit/xre/libxulapp_s.a  ../../staticlib/components/libnecko.a

../../staticlib/components/libuconv.a ../../staticlib/components/libi18n.a

../../staticlib/components/libchardet.a ../../staticlib/components/libjar50
.a

../../staticlib/components/libstartupcache.a

../../staticlib/components/libpref.a ../../staticlib/components/libhtmlpars
.a

../../staticlib/components/libidentity.a

../../staticlib/components/libimglib2.a ../../staticlib/components/libgkgfx
.a

../../staticlib/components/libgklayout.a

../../staticlib/components/libdocshell.a

../../staticlib/components/libembedcomponents.a

../../staticlib/components/libwebbrwsr.a

../../staticlib/components/libnsappshell.a

../../staticlib/components/libtxmgr.a

../../staticlib/components/libcommandlines.a

../../staticlib/components/libtoolkitcomps.a

../../staticlib/components/libpipboot.a ../../staticlib/components/libpipns
s.a

../../staticlib/components/libappcomps.a

../../staticlib/components/libjsreflect.a

../../staticlib/components/libcomposer.a

../../staticlib/components/libtelemetry.a

../../staticlib/components/libjsinspector.a

../../staticlib/components/libjsdebugger.a

../../staticlib/components/libstoragecomps.a

../../staticlib/components/librdf.a ../../staticlib/components/libwindowds.a

../../staticlib/components/libjsctypes.a ../../staticlib/components/libjspe
rf.a

../../staticlib/components/libgkplugin.a

../../staticlib/components/libunixproxy.a ../../staticlib/components/libjsd
.a

../../staticlib/components/libautoconfig.a ../../staticlib/components/libau
th.a

../../staticlib/components/libcookie.a

../../staticlib/components/libpermissions.a

../../staticlib/components/libuniversalchardet.a

../../staticlib/components/libfileview.a ../../staticlib/components/libplac
es.a

../../staticlib/components/libtkautocomplete.a

../../staticlib/components/libsatchel.a ../../staticlib/components/libpippk
i.a

../../staticlib/components/libwidget_gtk2.a

../../staticlib/components/libimgicon.a

../../staticlib/components/libaccessibility.a

../../staticlib/components/libremoteservice.a

../../staticlib/components/libspellchecker.a

../../staticlib/components/libzipwriter.a

../../staticlib/components/libservices-crypto.a

../../staticlib/components/libnkgio.a ../../staticlib/libjsipc_s.a

../../staticlib/libdomipc_s.a ../../staticlib/libdomplugins_s.a

../../staticlib/libmozipc_s.a ../../staticlib/libmozipdlgen_s.a

../../staticlib/libipcshell_s.a ../../staticlib/libgfxipc_s.a

../../staticlib/libhal_s.a ../../staticlib/libdombindings_s.a

../../staticlib/libxpcom_core.a ../../staticlib/libucvutil_s.a

../../staticlib/libchromium_s.a ../../staticlib/libsnappy_s.a

../../staticlib/libgtkxtbin.a ../../staticlib/libthebes.a

../../staticlib/libgl.a ../../staticlib/libycbcr.a  -L../../dist/bin

-L../../dist/lib /«PKGBUILDDIR»/build-xulrunner/dist/lib/libmozjs
.a

-L/usr/lib/ia64-linux-gnu -lssl3 -lsmime3 -lnss3 -lnssutil3 -lcrmf -lcairo
   

-lXrender -lcairo -lXext -lX11    -lsqlite3    -ljpeg -lz -lhunspell-1.3 
 

-L/usr/lib -levent -lvpx   -lpixman-1   ../../dist/lib/libgkmedias.a  -laso
und 

  -L../../dist/bin -L../../dist/lib  -L/usr/lib/ia64-linux-gnu -lplds4 -lpl
c4

-lnspr4 -lpthread -ldl ../../dist/lib/libmozalloc.a -ldbus-glib-1 -ldbus-1

-lgobject-2.0 -lglib-2.0    -lX11  -lXext  -lpangoft2-1.0 -lfreetype

-lfontconfig -lpangocairo-1.0 -lpango-1.0 -lcairo -lgobject-2.0 -lglib-2.0
  

-lfontconfig   -lgtk-x11-2.0 -latk-1.0 -lgio-2.0 -lpangoft2-1.0 -lfreetype

-lfontconfig -lgdk-x11-2.0 -lpangocairo-1.0 -lgdk_pixbuf-2.0 -lpango-1.0

-lcairo -lgobject-2.0 -lglib-2.0   -lXt -lgthread-2.0 -lfreetype  

-lstartup-notification-1    -ldl  -lrt    

/usr/bin/ld: Warning: gc-sections option ignored

/usr/bin/ld: ../xre/nsAppRunner.o: Can't relax br (PCREL21B) to

`nsCOMPtr_base::begin_assignment()' at 0x32 in section

`.text._ZL32ProfileServiceFactoryConstructorRKN7mozilla6ModuleERKNS0_8CIDEn
tryE'

with size 0x80 (> 0x1000000).

/usr/bin/ld: final link failed: Nonrepresentable section on output

collect2: ld returned 1 exit status

make[5]: *** [libxul.so] Error 1

make[5]: Leaving directory `/«PKGBUILDDIR»/build-xulrunner/toolki
t/library'

make[4]: *** [libs_tier_platform] Error 2

make[3]: *** [tier_platform] Error 2

make[2]: *** [default] Error 2

make[4]: Leaving directory `/«PKGBUILDDIR»/build-xulrunner'

make[3]: Leaving directory `/«PKGBUILDDIR»/build-xulrunner'

make[2]: Leaving directory `/«PKGBUILDDIR»/build-xulrunner'

dh_auto_build: make -j2 JS_READLINE=1 returned exit code 2

make[1]: *** [stamps/build-xulrunner] Error 2

make[1]: Leaving directory `/«PKGBUILDDIR»'

make: *** [build] Error 2







In toolkit/xre/nsAppRunner.cpp you can read:



static already_AddRefed<nsIFactory>

ProfileServiceFactoryConstructor(const mozilla::Module& module, const

mozilla::Module::CIDEntry& entry)

{

  nsCOMPtr<nsIFactory> factory;

  NS_NewToolkitProfileFactory(getter_AddRefs(factory));

  return factory.forget();

}





objdump -d build-xulrunner/toolkit/xre/nsAppRunner.o

reports:



...

0000000000000000

<_ZL32ProfileServiceFactoryConstructorRKN7mozilla6ModuleERKNS0_8CIDEntryE>:

   0:    18 08 11 06 80 05     [MMB]       alloc r33=ar.pfs,4,3,0

   6:    c0 80 33 7e 46 00                 adds r12=-16,r12

   c:    00 00 00 20                       nop.b 0x0

  10:    03 10 01 02 00 21     [MII]       mov r34=r1

  16:    00 02 00 62 00 c0                 mov r32=b0;;

  1c:    01 61 00 84                       adds r14=16,r12;;

  20:    08 00 00 00 01 00     [MMI]       nop.m 0x0

  26:    30 02 38 00 42 00                 mov r35=r14

  2c:    00 00 04 00                       nop.i 0x0

  30:    19 00 00 1c 98 11     [MMB]       st8 [r14]=r0

  36:    00 00 00 02 00 00                 nop.m 0x0

  3c:    08 00 00 50                       br.call.sptk.many b0=30

<_ZL32ProfileServiceFactoryConstructorRKN7mozilla6ModuleERKNS0_8CIDEntryE+0
x30>;;

  40:    11 08 00 44 00 21     [MIB]       mov r1=r34

  46:    30 02 20 00 42 00                 mov r35=r8

  4c:    08 00 00 50                       br.call.sptk.many b0=40

<_ZL32ProfileServiceFactoryConstructorRKN7mozilla6ModuleERKNS0_8CIDEntryE+0
x40>;;

  50:    09 70 40 18 00 21     [MMI]       adds r14=16,r12

  56:    00 00 00 02 00 20                 nop.m 0x0

  5c:    00 10 01 84                       mov r1=r34;;

  60:    02 40 00 1c 18 10     [MII]       ld8 r8=[r14]

  66:    00 08 01 55 00 00                 mov.i ar.pfs=r33;;

  6c:    00 0a 00 07                       mov b0=r32

  70:    19 00 00 00 01 00     [MMB]       nop.m 0x0

  76:    c0 80 30 00 42 80                 adds r12=16,r12

  7c:    08 00 84 00                       br.ret.sptk.many b0;;



...







There isn't any reference to a symbol `nsCOMPtr_base::begin_assignment()';

there is neither `nsCOMPtr_base' nor `begin_assignment()' in the entire out
put

of objdump.

The error message of ld is nonsense, it's a bug of ld.



It turned out that the --no-keep-memory makes the difference. The problem

doesn't occur when the --no-keep-memory switch is removed.







The error message "Can't relax br (PCREL21B) to .." just means that ld fail
ed

to calculate the 21-bits relocation of a br instruction because the target 
of

br was out of the address range of the relative 21-bits address mode.

It turned out that it occurs because ld took a wrong external symbol when it

attempted to relocate the mentioned section. It was caused by erroneous

dropping some modified relocation data due to the --no-keep-memory switch; 
ld

read the relocation data from the input file again after that and continued

working with stale relocation data.



The problem is in bfd/elfnn-ia64.c in the function elfNN_ia64_relax_section
():

It reads the relocs from a file if necessary:



  internal_relocs = (_bfd_elf_link_read_relocs

             (abfd, sec, NULL, (Elf_Internal_Rela *) NULL,

              link_info->keep_memory));



If keep_memory is true, _bfd_elf_link_read_relocs() allocates the memory for

internal_relocs once and stores the pointer at elf_section_data (sec)->relo
cs;

it returns that pointer as well.

If keep_memory is false, _bfd_elf_link_read_relocs() returns either existing

memory/data - if elf_section_data (sec)->relocs is *not* NULL. Otherwise it

allocates new memory and fills it out (by reading in a file); elf_section_d
ata

(sec)->relocs remains unchanged (is still NULL).



Some processing follows in elfNN_ia64_relax_section(), which may modify the

data in the internal_relocs[] array.

When it modifies anything, it sets a local variable changed_relocs to TRUE.



Finally the memory is freed if it is neither kept memory nor modified

(indicated by changed_relocs).



  if (elf_section_data (sec)->relocs != internal_relocs)

    {

      if (!changed_relocs)

    free (internal_relocs);

      else

    elf_section_data (sec)->relocs = internal_relocs;

    }





The bug is that changed_relocs was not set correctly to TRUE on some condit
ion

in elfNN_ia64_relax_section().



This is Debian bug#720404

(http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=720404).



A proposal for a patch is attached. Of course I have tested it; it fixes the

problem.



Stephan



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