cc1 segfaults during bootstrap on ARM...

[Scott Bambrough <scottb at netwinder dot org>]

The current mainline compiler segfaults during the bootstrap of the compiler.

[scottb@dirac gcc]$ ./xgcc -v
Using builtin specs.
gcc version 2.96 20000501 (experimental)

[scottb@dirac gcc]$ uname -a
Linux dirac 2.2.14-20000317 #1 Sat Mar 25 07:39:52 EST 2000 armv4l unknown

I configured with the following:

CFLAGS="-g -O0" ../gcc-2.96/configure --host=armv4l-unknown-linux-gnu 
  --with-cpu=strongarm --enable-shared

When I do a `make bootstrap-lean` it fails with the following error:

for name in _muldi3 _divdi3 _moddi3 _udivdi3 _umoddi3 _negdi2 _lshrdi3 
_ashldi3 _ashrdi3 _ffsdi2 _udiv_w_sdiv _udivmoddi4 _cmpdi2 _ucmpdi2 
_floatdidf _floatdisf _fixunsdfsi _fixunssfsi _fixunsdfdi _fixdfdi 
_fixunssfdi _fixsfdi _fixxfdi _fixunsxfdi _floatdixf _fixunsxfsi _fixtfdi 
_fixunstfdi _floatditf __gcc_bcmp _varargs __dummy _eprintf _bb _shtab
_clear_cache _trampoline __main _exit _ctors _pure; \
do \
  echo ${name}; \
  ./xgcc -B/usr/local/armv4l-unknown-linux-gnu/bin/ -B./ 
     -isystem /usr/local/armv4l-unknown-linux-gnu/include -O2
     -DIN_GCC -W -Wall -Wtraditional -O2 -g -O0 -isystem ./include  
     -fomit-frame-pointer -fPIC -g0 -DHAVE_GTHR_DEFAULT -DIN_LIBGCC2 
     -D__GCC_FLOAT_NOT_NEEDED   -I. -I../../gcc-2.96/gcc 
     -I../../gcc-2.96/gcc/config -I../../gcc-2.96/gcc/../include 
     -c -DL${name} \
         ../../gcc-2.96/gcc/libgcc2.c -o ${name}.o; \
  if [ $? -eq 0 ] ; then true; else exit 1; fi; \
  ar  rc tmplibgcc2.a ${name}.o; \
  rm -f ${name}.o; \
done
_muldi3
xgcc: Internal compiler error: program cc1 got fatal signal 11
make[4]: *** [libgcc2.a] Error 1
make[4]: Leaving directory `/home/scottb/cvstree/gcc-2.96-build/gcc'

cc1 fails running this command line:

./cc1 libgcc2.i -quiet -dumpbase libgcc2.c -g -g0 -O2 -O2 -O0 -W -Wall 
  -Wtraditional -version -fomit-frame-pointer -fPIC -o libgcc2.s

cc1: memory violation at pc=0x0227a10c, lr=0x022723b0 (bad
address=0x2f636377, code 0)

Running under GDB and looking at frame 0 on the stack:

(gdb) frame 0
#0  poplevel (keep=0, reverse=0, functionbody=0)
    at ../../gcc-2.96/gcc/c-decl.c:1052
1052      if (block_previously_created)
(gdb) l
1047         or if this level is a function body,
1048         create a BLOCK to record them for the life of this function. 
*/
1049
1050      block = 0;
1051      block_previously_created = (current_binding_level->this_block !=
0);
1052      if (block_previously_created)
1053        block = current_binding_level->this_block;
1054      else if (keep || functionbody
1055               || (current_binding_level->keep_if_subblocks && subblocks
!=
0))
1056        block = make_node (BLOCK);

(gdb) l
1057      if (block != 0)
1058        {
1059          BLOCK_VARS (block) = decls;
1060          BLOCK_SUBBLOCKS (block) = subblocks;
1061        }

The code segfaults on line 1059.

(gdb) p block
$6 = 0x2f636367
(gdb) p *block
Cannot access memory at address 0x2f636367

The address contained in block is invalid.  It is set on line 1053 based on
a value read from current_binding_level.

(gdb) p *current_binding_level
$4 = {names = 0x0, tags = 0x0, shadowed = 0x0, blocks = 0x0,
  this_block = 0x2f636367, level_chain = 0x23094f8, parm_flag = 1 '\001',
  tag_transparent = 0 '\000', subblocks_tag_transparent = 47 '/',
  keep = 0 '\000', keep_if_subblocks = 0 '\000', n_incomplete = 1768697197,
  parm_order = 0x0}

(gdb) p *current_binding_level->level_chain
$9 = {names = 0x40111b00, tags = 0x0, shadowed = 0x0, blocks = 0x0,
  this_block = 0x0, level_chain = 0x0, parm_flag = 0 '\000',
  tag_transparent = 0 '\000', subblocks_tag_transparent = 0 '\000',
  keep = 0 '\000', keep_if_subblocks = 0 '\000', n_incomplete = 1,
  parm_order = 0x0}

It looks to me like current_binding_level is incorrect here.  Am I on the
right track?

Scott

-- 
Scott Bambrough - Software Engineer
REBEL.COM    http://www.rebel.com
NetWinder    http://www.netwinder.org

libgcc2.i.gz