This PR is motivated by the thread at https://groups.google.com/forum/#!topic/comp.lang.fortran/lH-Pi0MbZZ4 Before revision r237735 the output of the following test print "(f0.0)", huge(1.0) print "(f0.0)", huge(1.0_8) print "(f0.0)", huge(1.0_10) print "(f0.0)", huge(1.0_16) end was 340282346638528859811704183484516925440. 179769313486231570814527423731704356798070567525844996598917476803157260780028538760589558632766878171540458953514382464234321326889464182768467546703537516986049910576551282076245490090389328944075868508455133942304583236903222948165808559332123348274797826204144723168738177180919299881250404026184124858368. 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Starting at that revision the output became 340282346638528859811704183484516925440. a.out(42020,0x7fff78eb2000) malloc: *** error for object 0x7fff5f902ed0: pointer being freed was not allocated *** set a breakpoint in malloc_error_break to debug Program received signal SIGABRT: Process abort signal. The only relevant part of the standard I have found is > 10.7.2.3.2 F editing > 1 The Fw.d edit descriptor indicates that the field occupies w positions, > except when w is zero in which case the processor selects the field width. > The fractional part of the field consists of d digits. > On input, w shall not be zero. I am not 100% sure about the interpretation of "the processor selects the field width", but I understand it as "the minimal width to output the number without *". If I am correct, the expected behavior is the one before r237735. Note that the following code print "(f8.0)", huge(1.0) print "(f18.0)", huge(1.0_8) print "(f20.0)", huge(1.0_10) print "(f40.0)", huge(1.0_16) end gives ******** ****************** ******************** **************************************** before r237735 and ******** ****************** Program received signal SIGSEGV: Segmentation fault - invalid memory reference. after it.
Author: jvdelisle Date: Wed Aug 31 17:45:26 2016 New Revision: 239900 URL: https://gcc.gnu.org/viewcvs?rev=239900&root=gcc&view=rev Log: 2016-08-31 Jerry DeLisle <jvdelisle@gcc.gnu.org> PR libgfortran/77393 * io/write.c (kind_from_size): New function to calculate required buffer size based on kind type. (select_buffer, select_string): Use new function. (write_float_0, write_real, write_real_g0, write_complex): Adjust calls to pass parameters needed by new function. Modified: trunk/libgfortran/ChangeLog trunk/libgfortran/io/write.c
Author: jvdelisle Date: Wed Aug 31 17:54:32 2016 New Revision: 239901 URL: https://gcc.gnu.org/viewcvs?rev=239901&root=gcc&view=rev Log: 2016-08-31 Jerry DeLisle <jvdelisle@gcc.gnu.org> PR libgfortran/77393 * gfortran.dg/fmt_f0_2.f90: New test. Added: trunk/gcc/testsuite/gfortran.dg/fmt_f0_2.f90 Modified: trunk/gcc/testsuite/ChangeLog
At revision r239908 the second test in comment 0 still gives ******** ****************** Program received signal SIGSEGV: Segmentation fault - invalid memory reference. at run time.
(In reply to Dominique d'Humieres from comment #3) > At revision r239908 the second test in comment 0 still gives > > ******** > ****************** > > Program received signal SIGSEGV: Segmentation fault - invalid memory > reference. > > at run time. Works for me here!
Author: jvdelisle Date: Thu Sep 1 21:17:42 2016 New Revision: 239945 URL: https://gcc.gnu.org/viewcvs?rev=239945&root=gcc&view=rev Log: 2016-09-01 Jerry DeLisle <jvdelisle@gcc.gnu.org> PR libgfortran/77393 * gfortran.dg/fmt_f0_2.f90: Update tests for available kinds. Modified: trunk/gcc/testsuite/ChangeLog trunk/gcc/testsuite/gfortran.dg/fmt_f0_2.f90
The update to the test case should correct any platform specific KIND issues. May need to upsize the bufers a little for Dominique's issue. I set the buffers tight so we could catch different behaviors on platforms I do not have access for testing.
> Works for me here! Are you sure that you have tested print "(f8.0)", huge(1.0) print "(f18.0)", huge(1.0_8) print "(f20.0)", huge(1.0_10) print "(f40.0)", huge(1.0_16) end ?
(In reply to Dominique d'Humieres from comment #7) > > Works for me here! > > Are you sure that you have tested > > print "(f8.0)", huge(1.0) > print "(f18.0)", huge(1.0_8) > print "(f20.0)", huge(1.0_10) > print "(f40.0)", huge(1.0_16) > end > > ? $ cat pr77393-b.f90 print "(f8.0)", huge(1.0) print "(f18.0)", huge(1.0_8) print "(f20.0)", huge(1.0_10) print "(f40.0)", huge(1.0_16) end $ gfc pr77393-b.f90 $ ./a.out ******** ****************** ******************** **************************************** $ gfc -v Using built-in specs. COLLECT_GCC=gfc COLLECT_LTO_WRAPPER=/home/jerry/dev/usr/libexec/gcc/x86_64-pc-linux-gnu/7.0.0/lto-wrapper Target: x86_64-pc-linux-gnu Configured with: ../trunk/configure --prefix=/home/jerry/dev/usr --enable-languages=c,c++,fortran --disable-libmudflap --enable-libgomp --disable-bootstrap Thread model: posix gcc version 7.0.0 20160831 (experimental) (GCC) Yes, as posted. I suspect, assuming you are on Darwin, that the implementation of snprintf emits a larger number of bytes. I found on the system here that it emits the number of characters I used in the routine with the adders. Can you test by changing the define in write.c line 1349: #define BUF_STACK_SZ 256 to something absurd like 6000. Then run this and see how large the strings are: program testbigf0 ! Can enormous numbers be printed with F0.0 format? implicit none character(10000) :: str write(str,"(f0.0)") -huge(1.0) print *, len(trim(str)) write(str,"(f0.0)") -huge(1.0_8) print *, len(trim(str)) write(str,"(f0.0)") -huge(1.0_10) print *, len(trim(str)) write(str,"(f0.0)") -huge(1.0_16) print *, len(trim(str)) end program testbigf0 Also using gdb can you see where the segfault occurs with the pr77393-b.f90 version above.
> Can you test by changing the define in write.c line 1349: > > #define BUF_STACK_SZ 256 On x86_64-apple-darwin15 the threshold (minimal value without SIGSEGV) is 385 with -m64 and 596 with -m32.
The test FAILs on Solaris (both sparc and x86, both 32 and 64-bit): FAIL: gfortran.dg/fmt_f0_2.f90 -O0 execution test FAIL: gfortran.dg/fmt_f0_2.f90 -O1 execution test FAIL: gfortran.dg/fmt_f0_2.f90 -O2 execution test FAIL: gfortran.dg/fmt_f0_2.f90 -O3 -fomit-frame-pointer -funroll-loops -fpeel-loops -ftracer -finline-functions execution test FAIL: gfortran.dg/fmt_f0_2.f90 -O3 -g execution test FAIL: gfortran.dg/fmt_f0_2.f90 -Os execution test Note: The following floating-point exceptions are signalling: IEEE_OVERFLOW_FLAG ERROR STOP FAILED AT LINE 23 Error termination. Backtrace: Rainer
(In reply to Rainer Orth from comment #10) > The test FAILs on Solaris (both sparc and x86, both 32 and 64-bit): > > FAIL: gfortran.dg/fmt_f0_2.f90 -O0 execution test > FAIL: gfortran.dg/fmt_f0_2.f90 -O1 execution test > FAIL: gfortran.dg/fmt_f0_2.f90 -O2 execution test > FAIL: gfortran.dg/fmt_f0_2.f90 -O3 -fomit-frame-pointer -funroll-loops > -fpeel-loops -ftracer -finline-functions execution test > FAIL: gfortran.dg/fmt_f0_2.f90 -O3 -g execution test > FAIL: gfortran.dg/fmt_f0_2.f90 -Os execution test > > Note: The following floating-point exceptions are signalling: > IEEE_OVERFLOW_FLAG > ERROR STOP FAILED AT LINE 23 > > Error termination. Backtrace: > > Rainer The test case also fails on PowerPC and other architectures because it makes assumptions about the number of digits being generated by the snprintf functions. I will be changing that shortly which will resolve the ERROR STOP. Can you confirm whether or not you get a segfault with the following from comment 2. print "(f8.0)", huge(1.0) print "(f18.0)", huge(1.0_8) print "(f20.0)", huge(1.0_10) print "(f40.0)", huge(1.0_16) end
Created attachment 39577 [details] Patch for testing, fixes comment #2? This patch for testing. I have tested on x86_64-unknown-freebsd12.0 which also exhibited the issue with an invalid memory reference.
Author: jvdelisle Date: Tue Sep 6 23:22:26 2016 New Revision: 240018 URL: https://gcc.gnu.org/viewcvs?rev=240018&root=gcc&view=rev Log: 2016-09-06 Jerry DeLisle <jvdelisle@gcc.gnu.org> PR libgfortran/77393 * io/write_float.def (build_float_string): Recognize when the result will not fit in the user provided, star fill, and exit early. * gfortran.dg/fmt_f0_2.f90: Update test. * gfortran.dg/fmt_f0_3.f90: New test. Added: trunk/gcc/testsuite/gfortran.dg/fmt_f0_3.f90 Modified: trunk/gcc/testsuite/ChangeLog trunk/gcc/testsuite/gfortran.dg/fmt_f0_2.f90 trunk/libgfortran/ChangeLog trunk/libgfortran/io/write_float.def
> --- Comment #13 from Jerry DeLisle <jvdelisle at gcc dot gnu.org> --- > Author: jvdelisle > Date: Tue Sep 6 23:22:26 2016 > New Revision: 240018 > > URL: https://gcc.gnu.org/viewcvs?rev=240018&root=gcc&view=rev > Log: > 2016-09-06 Jerry DeLisle <jvdelisle@gcc.gnu.org> > > PR libgfortran/77393 > * io/write_float.def (build_float_string): Recognize when the > result will not fit in the user provided, star fill, and exit > early. > > * gfortran.dg/fmt_f0_2.f90: Update test. > * gfortran.dg/fmt_f0_3.f90: New test. I've only now managed to test the patch: it passes on both i386-pc-solaris2.12 and sparc-sun-solaris2.12. Thanks. Rainer
Closing, Fixed