"error: thread-local storage not supported for this target"

Question

I have a program that uses the __thread specifier, to be run on a Solaris 9/UltraSprac.
I am not able to compile it using gcc 3.4.4 or 4.0.4, it emits the msg "error: thread-local storage not supported for this target".
xz@gamera% gcc -v -Wall -D_REENTRANT -c -o func_stack.o func_stack.c
Reading specs from /opt/gcc/3.4.4/lib/gcc/sparc-sun-solaris2.8/3.4.4/specs
Configured with: ../srcdir/configure --prefix=/opt/gcc/3.4.4 --disable-nls
Thread model: posix
gcc version 3.4.4
/opt/gcc/3.4.4/libexec/gcc/sparc-sun-solaris2.8/3.4.4/cc1 -quiet -v -D_REENTRANT -DMESS func_stack.c -quiet -dumpbase func_stack.c -mcpu=v7 -auxbase-strip func_stack.o -Wall -version -o /var/tmp//cc0poHSN.s
ignoring nonexistent directory "/usr/local/include"
ignoring nonexistent directory "/opt/gcc/3.4.4/lib/gcc/sparc-sun-solaris2.8/3.4.4/../../../../sparc-sun-solaris2.8/include"
#include "..." search starts here:
#include <...> search starts here:
/opt/gcc/3.4.4/include
/opt/gcc/3.4.4/lib/gcc/sparc-sun-solaris2.8/3.4.4/include
/usr/include
End of search list.
GNU C version 3.4.4 (sparc-sun-solaris2.8)
        compiled by GNU C version 3.4.4.
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
func_stack.c:16: error: thread-local storage not supported for this target
func_stack.c:17: error: thread-local storage not supported for this target
func_stack.c:19: error: thread-local storage not supported for this target
xs@gamera% gcc -v -D_REENTRANT  -c -o func_stack.o func_stack.c
Using built-in specs.
Target: sparc-sun-solaris2.9
Configured with: /net/clpt-v490-0/export/data/bldmstr/20070711_mars_gcc/src/configure --prefix=/usr/sfw --enable-shared --with-system-zlib --enable-checking=release --disable-libmudflap --enable-languages=c,c++ --enable-version-specific-runtime-libs --with-cpu=v9 --with-ld=/usr/ccs/bin/ld --without-gnu-ld
Thread model: posix
gcc version 4.0.4 (gccfss)
/pkg/gcc/4.0.4/bin/../libexec/gcc/sparc-sun-solaris2.9/4.0.4/cc1 -quiet -v -I. -iprefix /pkg/gcc/4.0.4/bin/../lib/gcc/sparc-sun-solaris2.9/4.0.4/ -D__sparcv8 -D_REENTRANT -DMESS func_stack.c -quiet -dumpbase func_stack.c -mcpu=v9 -auxbase-strip func_stack.o -version -m32 -o /tmp/ccjsdswh.s -r /tmp/cc2w4ZRo.ir
ignoring nonexistent directory "/pkg/gcc/4.0.4/bin/../lib/gcc/sparc-sun-solaris2.9/4.0.4/../../../../sparc-sun-solaris2.9/include"
ignoring nonexistent directory "/usr/local/include"
ignoring nonexistent directory "/usr/sfw/lib/gcc/sparc-sun-solaris2.9/4.0.4/include"
ignoring nonexistent directory "/usr/sfw/lib/../sparc-sun-solaris2.9/include"
#include "..." search starts here:
#include <...> search starts here:
/pkg/gcc/4.0.4/bin/../lib/gcc/sparc-sun-solaris2.9/4.0.4/include
/usr/sfw/include
/usr/include
End of search list.
GNU C version 4.0.4 (gccfss) (sparc-sun-solaris2.9)
        compiled by GNU C version 4.0.4 (gccfss).
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
func_stack.c:16: error: thread-local storage not supported for this target
func_stack.c:17: error: thread-local storage not supported for this target
func_stack.c:19: error: thread-local storage not supported for this targetJust as comparison, the corresponding output of compiling another file which does not have __thread declaration is as follows:
xz@gamera% gcc -v -Wall -D_REENTRANT -c -o common.o common.c
Reading specs from /opt/gcc/3.4.4/lib/gcc/sparc-sun-solaris2.8/3.4.4/specs
Configured with: ../srcdir/configure --prefix=/opt/gcc/3.4.4 --disable-nls
Thread model: posix
gcc version 3.4.4
/opt/gcc/3.4.4/libexec/gcc/sparc-sun-solaris2.8/3.4.4/cc1 -quiet -v -D_REENTRANT -DMESS common.c -quiet -dumpbase common.c -mcpu=v7 -auxbase-strip common.o -Wall -version -o /var/tmp//cc4VxrLz.s
ignoring nonexistent directory "/usr/local/include"
ignoring nonexistent directory "/opt/gcc/3.4.4/lib/gcc/sparc-sun-solaris2.8/3.4.4/../../../../sparc-sun-solaris2.8/include"
#include "..." search starts here:
#include <...> search starts here:
/opt/gcc/3.4.4/include
/opt/gcc/3.4.4/lib/gcc/sparc-sun-solaris2.8/3.4.4/include
/usr/include
End of search list.
GNU C version 3.4.4 (sparc-sun-solaris2.8)
        compiled by GNU C version 3.4.4.
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
/usr/ccs/bin/as -V -Qy -s -xarch=v8 -o common.o /var/tmp//cc4VxrLz.s
/usr/ccs/bin/as: Sun WorkShop 6 update 2 Compiler Common 6.2 Solaris_9_CBE 2001/04/02Note that the last 2 lines seem to suggest that a Sun assembler is used as the back-end of gcc. I am not sure whether the failure to compile the first file (with __thread) was due to the incompatibility of this Sun assembler. In the first case, the error msg was emitted before these 2 lines are printed.
I further read a post about gcc 3.3.3's inability to compile code that has __thread in it, on a HP-UX 11.11: http://forums12.itrc.hp.com/service/forums/questionanswer.do?admit=109447627+1216595175060+28353475&threadId=1148976 The conclusion seems to suggest that "the 2.17 GNU assembler did not support thread local storage" and gcc sees that and thus disallows TLS.
If the assembler is the culprit, then does anyone know whether this "Sun WorkShop 6 update 2" assembler in my installation can work with TLS? And how come a Sun assembler becomes the back-end of gcc? I read that gas (the GNU assembler) is the default backend of gcc. (How) can one specify the assembler to be used for gcc?
As an aside, I am able to compile my file on this same Solaris 9/UltraSparc platform using the Sun Studio 12 C Compiler:
xz@gamera% cc -V -# -D_REENTRANT  -c -o func_stack.o func_stack.c
cc: Sun C 5.9 SunOS_sparc Patch 124867-01 2007/07/12
### Note: NLSPATH = /pkg/SUNWspro/12/prod/bin/../lib/locale/%L/LC_MESSAGES/%N.cat:/pkg/SUNWspro/12/prod/bin/../../lib/locale/%L/LC_MESSAGES/%N.cat
###     command line files and options (expanded):
### -c -D_REENTRANT  -V func_stack.c -o func_stack.o
/pkg/SUNWspro/12/prod/bin/acomp -xldscope=global -i func_stack.c -y-fbe -y/pkg/SUNWspro/12/prod/bin/fbe -y-xarch=generic -y-xmemalign=8i -y-o -yfunc_stack.o -y-verbose -y-xthreadvar=no%dynamic -y-comdat -xdbggen=no%stabs+dwarf2+usedonly -V -D_REENTRANT  -m32 -fparam_ir -Qy -D__SunOS_5_9 -D__SUNPRO_C=0x590 -D__SVR4 -D__sun -D__SunOS -D__unix -D__sparc -D__BUILTIN_VA_ARG_INCR -D__C99FEATURES__ -Xa -D__PRAGMA_REDEFINE_EXTNAME -Dunix -Dsun -Dsparc -D__RESTRICT -xc99=%all,no%lib -D__FLT_EVAL_METHOD__=0 -I/pkg/SUNWspro/12/prod/include/cc "-g/pkg/SUNWspro/12/prod/bin/cc -V -D_REENTRANT  -c -o func_stack.o " -fsimple=0 -D__SUN_PREFETCH -destination_ir=yabe
acomp: Sun C 5.9 SunOS_sparc Patch 124867-01 2007/07/12Interestingly, the output no longer mentions the "/usr/ccs/bin/as: Sun WorkShop 6 update 2" assembler.

Answer 1

Just as another comparison, I compiled a file without __thread on the Solaris 9/UltraSparc platform using gcc 4.0.4. Not surprisingly it worked. But I no longer see the mention of the Sun assembler as in the case of gcc 3.4.4. Nor did I see the mention of "GNU assembler" as in the case of gcc 4.0.4/Solaris 10/x86. Instead, I saw something called "iropt" and "cg". Does anyone know what they are?
xz@gamera% gcc -v -Wall -D_REENTRANT -c -o common.o common.c
Using built-in specs.
Target: sparc-sun-solaris2.9
Configured with: /net/clpt-v490-0/export/data/bldmstr/20070711_mars_gcc/src/configure --prefix=/usr/sfw --enable-shared --with-system-zlib --enable-checking=release --disable-libmudflap --enable-languages=c,c++ --enable-version-specific-runtime-libs --with-cpu=v9 --with-ld=/usr/ccs/bin/ld --without-gnu-ld
Thread model: posix
gcc version 4.0.4 (gccfss)
/pkg/gcc/4.0.4/bin/../libexec/gcc/sparc-sun-solaris2.9/4.0.4/cc1 -quiet -v -iprefix /pkg/gcc/4.0.4/bin/../lib/gcc/sparc-sun-solaris2.9/4.0.4/ -D__sparcv8 -D_REENTRANT -DMESS common.c -quiet -dumpbase common.c -mcpu=v9 -auxbase-strip common.o -Wall -version -m32 -o /tmp/ccSGJIDD.s -r /tmp/ccKuJz76.ir
ignoring nonexistent directory "/pkg/gcc/4.0.4/bin/../lib/gcc/sparc-sun-solaris2.9/4.0.4/../../../../sparc-sun-solaris2.9/include"
ignoring nonexistent directory "/usr/local/include"
ignoring nonexistent directory "/usr/sfw/lib/gcc/sparc-sun-solaris2.9/4.0.4/include"
ignoring nonexistent directory "/usr/sfw/lib/../sparc-sun-solaris2.9/include"
#include "..." search starts here:
#include <...> search starts here:
/pkg/gcc/4.0.4/bin/../lib/gcc/sparc-sun-solaris2.9/4.0.4/include
/usr/sfw/include
/usr/include
End of search list.
GNU C version 4.0.4 (gccfss) (sparc-sun-solaris2.9)
        compiled by GNU C version 4.0.4 (gccfss).
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
/pkg/gcc/4.0.4/SUNW0scgfss/4.0.4/prod/bin/iropt -F -xarch=v8plus -xchip=generic -O1 -xvector=no -xbuiltin=%none -xcache=generic -Qy -h_gcc -o /tmp/ccUl4mVM.ircg /tmp/ccKuJz76.ir -N/dev/null -is /tmp/ccSGJIDD.s
/pkg/gcc/4.0.4/SUNW0scgfss/4.0.4/prod/bin/cg -Qy -xarch=v8plus -xchip=generic -OO0 -T3 -Qiselect-C0 -Qrm:newregman:coalescing=0 -xcode=abs32 -xcache=generic -xmemalign=8i -il /pkg/gcc/4.0.4/bin/../lib/gcc/sparc-sun-solaris2.9/4.0.4//gccbuiltins.il -xvector=no -xthreadvar=no%dynamic -xbuiltin=%none -Qassembler-ounrefsym=0 -Qiselect-T0 -Qassembler-I -Qassembler-U -comdat -h_gcc -is /tmp/ccSGJIDD.s -ir /tmp/ccUl4mVM.ircg -oo common.o