Help required with strange linking bug

[charles.gauthier at iit.nrc.ca (Charles-Antoine Gauthier)]

Here is a strange problem with m68k-rtemself:

cdtest crashes when throwing the C++ exception. I have traced the
problem to a linking problem:

[gauthier at c55 cdtest]$ m68k-rtemself-nm o-mvme167-debug/cdtest.exe |
grep pthread_once
         U pthread_once

There is still one (and only one) undefined symbol in the executable
image, but the link was successful! The link command issued by 'make
RTEMS_BSP=mvme167 debug' was:

collect2 version 2.95 19990728 (release) (68k, Motorola syntax)
/usr/local/bin/m68k-rtemself-ld -v -dc -dp -N -e start -o
o-mvme167-debug/cdtest.exe
/home/gauthier/build-rtems/./mvme167/lib/start_g.o
/usr/local/lib/gcc-lib/m68k-rtemself/2.95/crti.o
/usr/local/lib/gcc-lib/m68k-rtemself/2.95/crtbegin.o
-L/home/gauthier/build-rtems/./mvme167/lib
-L/usr/local/lib/gcc-lib/m68k-rtemself/2.95
-L/usr/local/m68k-rtemself/lib o-mvme167-debug/init.o
o-mvme167-debug/main.o
/home/gauthier/build-rtems/./mvme167/lib/libtest_g.a -lgcc --start-group
-lrtemsall_g -lc -lgcc --end-group -T
/home/gauthier/build-rtems/./mvme167/lib/elflinkcmds -lgcc -lrtemsall_g
/usr/local/lib/gcc-lib/m68k-rtemself/2.95/crtend.o
/usr/local/lib/gcc-lib/m68k-rtemself/2.95/crtn.o
GNU ld version 2.9.1 (with BFD 2.9.1)

I checked librtemsall_g.a. A section of the output of
m68k-rtemself-objdump -j .text -d librtemsall_g.a appears below:


pthreadonce.o:     file format elf32-m68k

Disassembly of section .text:

00000000 <pthread_once>:
   0:	4856           	pea %fp@
   2:	2c4f           	moveal %sp,%fp
   4:	2f0a           	movel %a2,%sp at -
   6:	4aae 0008      	tstl %fp@(8)
   a:	670a           	beqs 16 <pthread_once+0x16>
   c:	4aae 000c      	tstl %fp@(12)
  10:	6608           	bnes 1a <pthread_once+0x1a>
  12:	6000 0002      	braw 16 <pthread_once+0x16>
  16:	7016           	moveq #22,%d0
  18:	6034           	bras 4e <pthread_once+0x4e>
  1a:	4eb9 0000 0000 	jsr 0 <pthread_once>
  20:	206e 0008      	moveal %fp@(8),%a0
  24:	4aa8 0004      	tstl %a0@(4)
  28:	6618           	bnes 42 <pthread_once+0x42>
  2a:	206e 0008      	moveal %fp@(8),%a0
  2e:	7001           	moveq #1,%d0
  30:	2080           	movel %d0,%a0@
  32:	206e 0008      	moveal %fp@(8),%a0
  36:	7001           	moveq #1,%d0
  38:	2140 0004      	movel %d0,%a0@(4)
  3c:	246e 000c      	moveal %fp@(12),%a2
  40:	4e92           	jsr %a2@
  42:	4eb9 0000 0000 	jsr 0 <pthread_once>
  48:	4280           	clrl %d0
  4a:	6000 0002      	braw 4e <pthread_once+0x4e>
  4e:	246e fffc      	moveal %fp@(-4),%a2
  52:	4e5e           	unlk %fp
  54:	4e75           	rts

00000056 <_Thread_Disable_dispatch>:
  56:	4856           	pea %fp@
  58:	2c4f           	moveal %sp,%fp
  5a:	2039 0000 0000 	movel 0 <pthread_once>,%d0
  60:	2200           	movel %d0,%d1
  62:	5281           	addql #1,%d1
  64:	23c1 0000 0000 	movel %d1,0 <pthread_once>
  6a:	4e5e           	unlk %fp
  6c:	4e75           	rts

0000006e <_Thread_Enable_dispatch>:
  6e:	4856           	pea %fp@
  70:	2c4f           	moveal %sp,%fp
  72:	2039 0000 0000 	movel 0 <pthread_once>,%d0
  78:	2200           	movel %d0,%d1
  7a:	5381           	subql #1,%d1
  7c:	23c1 0000 0000 	movel %d1,0 <pthread_once>
  82:	2039 0000 0000 	movel 0 <pthread_once>,%d0
  88:	4a80           	tstl %d0
  8a:	6606           	bnes 92 <_Thread_Enable_dispatch+0x24>
  8c:	4eb9 0000 0000 	jsr 0 <pthread_once>
  92:	4e5e           	unlk %fp
  94:	4e75           	rts


The crash occurs because ld generated jsr 0 for a call to pthread_once()
in throw().

Any idea what the problem might be?

BTW, cdtest works fine if I link against pthreadonce.o to force
pthread_once into the image!



Environment:

rtems-19990709
binutils-2.9.1 with binutils-2.9.1-rtems-diff-19990804 patch
gcc-2.95 with gcc-2.95-rtems-diff-19990804 patch
newlib-1.8.1 with newlib-1.8.1-rtems-diff-19990708 patch
Pentium II with RedHat Linux 6.0 host

-- 
Charles-Antoine Gauthier
Research Officer
Software Engineering Group
Institute for Information Technology
National Research Council of Canada
Ottawa, ON, Canada
K1A 0R6