------- Comment #6 from hp at gcc dot gnu dot org 2008-12-07 21:42 -------
I noticed something odd while looking at simulator traces: running the
test-case streamio_1 at -O1 (passing) yielded a different execution path than
at -O0 (failing) *in the library*. At -O0, no write system calls were done for
that file but at -O1, I see libgfortran flushes and write calls. So, it looks
like internal inconsistency rather than target system oddness.
Anyway, I've been somewhat blind.
This gfortran.dg is a "torture-testsuite"; it iterates over -O0, -O1 etc. and
most failures happen at -O0 *only* so it should not have take more than a
glance to see that it cannot (for sane bugs) be a fault of the target system
(e.g. the lseek implementation). Instead, I believe the observed internal
inconsistency is due to a missing initialization on part of libgfortran, which
should explain why this isn't visible on all systems. Running streamio_1 from
r142537 at -O1 using valgrind on a native i686-unknown-linux-gnu (where FWIW no
gfortran test FAILs) seems to support this theory:
"env LD_LIBRARY_PATH=<copy this from your gfortran.log> valgrind -q
./streamio_1.exe" yields:
--9635-- Warning: DWARF2 CFI reader: unhandled DW_OP_ opcode 0x55
==9635== Conditional jump or move depends on uninitialised value(s)
==9635== at 0x40ABF47: finalize_transfer (transfer.c:2962)
==9635== by 0x40ABFE0: _gfortran_st_write_done (transfer.c:3130)
==9635== by 0x8048863: MAIN__ (in
/home/hp/gcc/o/gcc/testsuite/gfortran/streamio_1.exe)
==9635== by 0x8048ABA: main (fmain.c:21)
==9635==
==9635== Conditional jump or move depends on uninitialised value(s)
==9635== at 0x40ABF47: finalize_transfer (transfer.c:2962)
==9635== by 0x40ABFE0: _gfortran_st_write_done (transfer.c:3130)
==9635== by 0x80488B9: MAIN__ (in
/home/hp/gcc/o/gcc/testsuite/gfortran/streamio_1.exe)
==9635== by 0x8048ABA: main (fmain.c:21)
==9635==
==9635== Conditional jump or move depends on uninitialised value(s)
==9635== at 0x40ABF4D: finalize_transfer (transfer.c:2962)
==9635== by 0x40ABFE0: _gfortran_st_write_done (transfer.c:3130)
==9635== by 0x80488B9: MAIN__ (in
/home/hp/gcc/o/gcc/testsuite/gfortran/streamio_1.exe)
==9635== by 0x8048ABA: main (fmain.c:21)
==9635==
==9635== Conditional jump or move depends on uninitialised value(s)
==9635== at 0x40ABF58: finalize_transfer (transfer.c:2962)
==9635== by 0x40ABFE0: _gfortran_st_write_done (transfer.c:3130)
==9635== by 0x80488B9: MAIN__ (in
/home/hp/gcc/o/gcc/testsuite/gfortran/streamio_1.exe)
==9635== by 0x8048ABA: main (fmain.c:21)
==9635==
==9635== Conditional jump or move depends on uninitialised value(s)
==9635== at 0x40ABF47: finalize_transfer (transfer.c:2962)
==9635== by 0x40ABFE0: _gfortran_st_write_done (transfer.c:3130)
==9635== by 0x804890F: MAIN__ (in
/home/hp/gcc/o/gcc/testsuite/gfortran/streamio_1.exe)
==9635== by 0x8048ABA: main (fmain.c:21)
==9635==
==9635== Conditional jump or move depends on uninitialised value(s)
==9635== at 0x40ABF4D: finalize_transfer (transfer.c:2962)
==9635== by 0x40ABFE0: _gfortran_st_write_done (transfer.c:3130)
==9635== by 0x804890F: MAIN__ (in
/home/hp/gcc/o/gcc/testsuite/gfortran/streamio_1.exe)
==9635== by 0x8048ABA: main (fmain.c:21)
==9635==
==9635== Conditional jump or move depends on uninitialised value(s)
==9635== at 0x40ABF58: finalize_transfer (transfer.c:2962)
==9635== by 0x40ABFE0: _gfortran_st_write_done (transfer.c:3130)
==9635== by 0x804890F: MAIN__ (in
/home/hp/gcc/o/gcc/testsuite/gfortran/streamio_1.exe)
==9635== by 0x8048ABA: main (fmain.c:21)
==9635==
==9635== Conditional jump or move depends on uninitialised value(s)
==9635== at 0x40ABF47: finalize_transfer (transfer.c:2962)
==9635== by 0x40ABFE0: _gfortran_st_write_done (transfer.c:3130)
==9635== by 0x8048965: MAIN__ (in
/home/hp/gcc/o/gcc/testsuite/gfortran/streamio_1.exe)
==9635== by 0x8048ABA: main (fmain.c:21)
==9635==
==9635== Conditional jump or move depends on uninitialised value(s)
==9635== at 0x40ABF4D: finalize_transfer (transfer.c:2962)
==9635== by 0x40ABFE0: _gfortran_st_write_done (transfer.c:3130)
==9635== by 0x8048965: MAIN__ (in
/home/hp/gcc/o/gcc/testsuite/gfortran/streamio_1.exe)
==9635== by 0x8048ABA: main (fmain.c:21)
==9635==
==9635== Conditional jump or move depends on uninitialised value(s)
==9635== at 0x40ABF58: finalize_transfer (transfer.c:2962)
==9635== by 0x40ABFE0: _gfortran_st_write_done (transfer.c:3130)
==9635== by 0x8048965: MAIN__ (in
/home/hp/gcc/o/gcc/testsuite/gfortran/streamio_1.exe)
==9635== by 0x8048ABA: main (fmain.c:21)
==9635==
==9635== Conditional jump or move depends on uninitialised value(s)
==9635== at 0x40AD378: data_transfer_init (transfer.c:2144)
==9635== by 0x40AE09D: _gfortran_st_read (transfer.c:3069)
==9635== by 0x80489A9: MAIN__ (in
/home/hp/gcc/o/gcc/testsuite/gfortran/streamio_1.exe)
==9635== by 0x8048ABA: main (fmain.c:21)
==9635==
==9635== Conditional jump or move depends on uninitialised value(s)
==9635== at 0x40ABF47: finalize_transfer (transfer.c:2962)
==9635== by 0x40AC0C0: _gfortran_st_read_done (transfer.c:3101)
==9635== by 0x8048A2A: MAIN__ (in
/home/hp/gcc/o/gcc/testsuite/gfortran/streamio_1.exe)
==9635== by 0x8048ABA: main (fmain.c:21)
==9635==
==9635== Conditional jump or move depends on uninitialised value(s)
==9635== at 0x40ABF4D: finalize_transfer (transfer.c:2962)
==9635== by 0x40AC0C0: _gfortran_st_read_done (transfer.c:3101)
==9635== by 0x8048A2A: MAIN__ (in
/home/hp/gcc/o/gcc/testsuite/gfortran/streamio_1.exe)
==9635== by 0x8048ABA: main (fmain.c:21)
==9635==
==9635== Conditional jump or move depends on uninitialised value(s)
==9635== at 0x40ABF58: finalize_transfer (transfer.c:2962)
==9635== by 0x40AC0C0: _gfortran_st_read_done (transfer.c:3101)
==9635== by 0x8048A2A: MAIN__ (in
/home/hp/gcc/o/gcc/testsuite/gfortran/streamio_1.exe)
==9635== by 0x8048ABA: main (fmain.c:21)
(-v doesn't yield further details, but I'll attach -v output from valgrind when
streamio_1 is linked static. Lots of interesting libgfortran-related
information. :)
So, I'll unassign myself from this PR, but will stand by for assistance.
Jerry?
--
hp at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
AssignedTo|hp at gcc dot gnu dot org |unassigned at gcc dot gnu
| |dot org
Status|ASSIGNED |NEW
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38430
