| Message ID | 20161202013354.GA42106@troutmask.apl.washington.edu |
|---|---|
| State | New |
| Headers | show |
Hi Steve, 2016-12-02 2:33 GMT+01:00 Steve Kargl <sgk@troutmask.apl.washington.edu>: > The attached patch fixes an ICE, a nearby whitespace issue, and > removed the ATTRIBUTE_UNUSED tag. THe change has passed regression > testing on x86_64-*-freebsd. Ok to commit? huh, I don't really understand why the argument of RANK is detected to be an EXPR_FUNCTION for the test case at hand. Shouldn't it rather be an EXPR_CONSTANT? Some debugging in gfc_check_rank shows that a->symtree->n.sym indeed is the symbol "c" (as expected), but that clearly is not a function, so it seems to me that the actual bug here is that a->expr_type is set incorrectly ...? Cheers, Janus > 2016-12-01 Steven G. Kargl <kargl@gcc.gnu.org> > > PR fortran/78618 > * check.c (gfc_check_rank): Remove ATTRIBUTE_UNUSED. Fix whitespace. > Fix ICE where a NULL pointer is dereferenced. > * simplify.c (gfc_convert_char_constant): Do not buffer error. > > 2016-12-01 Steven G. Kargl <kargl@gcc.gnu.org> > > PR fortran/78618 > * gfortran.dg/char_conversion.f90: New test. > > -- > Steve
On Fri, Dec 02, 2016 at 04:47:19PM +0100, Janus Weil wrote: > Hi Steve, > > 2016-12-02 2:33 GMT+01:00 Steve Kargl <sgk@troutmask.apl.washington.edu>: > > The attached patch fixes an ICE, a nearby whitespace issue, and > > removed the ATTRIBUTE_UNUSED tag. THe change has passed regression > > testing on x86_64-*-freebsd. Ok to commit? > > huh, I don't really understand why the argument of RANK is detected to > be an EXPR_FUNCTION for the test case at hand. Shouldn't it rather be > an EXPR_CONSTANT? > > Some debugging in gfc_check_rank shows that a->symtree->n.sym indeed > is the symbol "c" (as expected), but that clearly is not a function, > so it seems to me that the actual bug here is that a->expr_type is set > incorrectly ...? > I found that it is the function __convert_s4_s1. Namely, we have character, parameter :: c = char(256,4) print *, rank(c) c is kind=1 and char(256,4) is kind 4. so, we end up with print *, rank(__convert_s4_s1(...)) As __convert_s4_s1() has neither isym nor esym set, you get a problem. -- Steve
On Fri, Dec 02, 2016 at 06:00:48PM +0100, Janus Weil wrote: > 2016-12-02 17:30 GMT+01:00 Steve Kargl <sgk@troutmask.apl.washington.edu>: > > On Fri, Dec 02, 2016 at 04:47:19PM +0100, Janus Weil wrote: > >> Hi Steve, > >> > >> 2016-12-02 2:33 GMT+01:00 Steve Kargl <sgk@troutmask.apl.washington.edu>: > >> > The attached patch fixes an ICE, a nearby whitespace issue, and > >> > removed the ATTRIBUTE_UNUSED tag. THe change has passed regression > >> > testing on x86_64-*-freebsd. Ok to commit? > >> > >> huh, I don't really understand why the argument of RANK is detected to > >> be an EXPR_FUNCTION for the test case at hand. Shouldn't it rather be > >> an EXPR_CONSTANT? > >> > >> Some debugging in gfc_check_rank shows that a->symtree->n.sym indeed > >> is the symbol "c" (as expected), but that clearly is not a function, > >> so it seems to me that the actual bug here is that a->expr_type is set > >> incorrectly ...? > > > > I found that it is the function __convert_s4_s1. > > That's strange. If we see different things here, maybe we are running > into some kind of undefined behavior (possibly related to > gfc_bad_expr?). Anyway, after some more debugging I came to the > conclusion that what actually fails is the error propagation, which > seems to be broken in gfc_check_assign and can be fixed like this: > > > Index: gcc/fortran/expr.c > =================================================================== > --- gcc/fortran/expr.c (revision 243194) > +++ gcc/fortran/expr.c (working copy) > @@ -3314,9 +3314,9 @@ gfc_check_assign (gfc_expr *lvalue, gfc_expr *rval > if (lvalue->ts.type == BT_CHARACTER && rvalue->ts.type == BT_CHARACTER) > { > if (lvalue->ts.kind != rvalue->ts.kind && allow_convert) > - gfc_convert_chartype (rvalue, &lvalue->ts); > - > - return true; > + return gfc_convert_chartype (rvalue, &lvalue->ts); > + else > + return true; > } > > if (!allow_convert) > > > This also avoids the ICE and I think is the proper way to fix this ... > When developing the patch, I fixed/avoided the ICE, first. Then, I tried Gerhard's second testcase without the PARAMETER attribute. An error message is emitted, so I went hunting for why PARAMETER suppressed the error message. This led to the second part of the patch of changing gfc_error to gfc_error_now. Perhaps, forcing the gfc_error_now prevents gfortran from inserting the __convert_s4_s1 call. In any event, if your patch causes an error message to be emitted, then I think that your patch is better than the one I proposed. Feel free to commit your patch. -- Steve
2016-12-02 19:06 GMT+01:00 Janus Weil <janus@gcc.gnu.org>: > 2016-12-02 18:13 GMT+01:00 Steve Kargl <sgk@troutmask.apl.washington.edu>: >>> >> > The attached patch fixes an ICE, a nearby whitespace issue, and >>> >> > removed the ATTRIBUTE_UNUSED tag. THe change has passed regression >>> >> > testing on x86_64-*-freebsd. Ok to commit? >>> >> >>> >> huh, I don't really understand why the argument of RANK is detected to >>> >> be an EXPR_FUNCTION for the test case at hand. Shouldn't it rather be >>> >> an EXPR_CONSTANT? >>> >> >>> >> Some debugging in gfc_check_rank shows that a->symtree->n.sym indeed >>> >> is the symbol "c" (as expected), but that clearly is not a function, >>> >> so it seems to me that the actual bug here is that a->expr_type is set >>> >> incorrectly ...? >>> > >>> > I found that it is the function __convert_s4_s1. >>> >>> That's strange. If we see different things here, maybe we are running >>> into some kind of undefined behavior (possibly related to >>> gfc_bad_expr?). Anyway, after some more debugging I came to the >>> conclusion that what actually fails is the error propagation, which >>> seems to be broken in gfc_check_assign and can be fixed like this: >>> >>> >>> Index: gcc/fortran/expr.c >>> =================================================================== >>> --- gcc/fortran/expr.c (revision 243194) >>> +++ gcc/fortran/expr.c (working copy) >>> @@ -3314,9 +3314,9 @@ gfc_check_assign (gfc_expr *lvalue, gfc_expr *rval >>> if (lvalue->ts.type == BT_CHARACTER && rvalue->ts.type == BT_CHARACTER) >>> { >>> if (lvalue->ts.kind != rvalue->ts.kind && allow_convert) >>> - gfc_convert_chartype (rvalue, &lvalue->ts); >>> - >>> - return true; >>> + return gfc_convert_chartype (rvalue, &lvalue->ts); >>> + else >>> + return true; >>> } >>> >>> if (!allow_convert) >>> >>> >>> This also avoids the ICE and I think is the proper way to fix this ... >>> >> >> When developing the patch, I fixed/avoided the ICE, first. Then, >> I tried Gerhard's second testcase without the PARAMETER attribute. >> An error message is emitted, so I went hunting for why PARAMETER >> suppressed the error message. This led to the second part of the >> patch of changing gfc_error to gfc_error_now. > > I think the gfc_error_now should not be necessary with my fix, but > removing the ATTRIBUTE_UNUSED is certainly a good idea. > > >> In any event, if your patch causes an error message to be emitted, >> then I think that your patch is better than the one I proposed. >> Feel free to commit your patch. > > I am now regtesting the attached version and, if successful, will commit. Testing went well. Committed as r243201. Cheers, Janus
On Fri, Dec 02, 2016 at 07:39:33PM +0100, Janus Weil wrote: > > Testing went well. Committed as r243201. > Thanks for reviewing my patch, and more importantly thanks for your patch. -- Steve
On Dez 01 2016, Steve Kargl <sgk@troutmask.apl.washington.edu> wrote: > PR fortran/78618 > * gfortran.dg/char_conversion.f90: New test. That test still crashes the compiler on m68k: /daten/aranym/gcc/gcc-20161203/gcc/testsuite/gfortran.dg/char_conversion.f90:8:30: Error: Character '\u0100' in string at (1) cannot be converted into character kind 1 f951: internal compiler error: Segmentation fault 0xb40a7f crash_signal ../../gcc/toplev.c:333 0x58dd52 gfc_is_constant_expr(gfc_expr*) ../../gcc/fortran/expr.c:899 0x5feb90 resolve_fl_procedure ../../gcc/fortran/resolve.c:12013 0x5feb90 resolve_symbol ../../gcc/fortran/resolve.c:14721 0x616e73 do_traverse_symtree ../../gcc/fortran/symbol.c:3994 0x6007d4 resolve_types ../../gcc/fortran/resolve.c:15948 0x5fc3e4 gfc_resolve ../../gcc/fortran/resolve.c:16061 0x5e70b2 resolve_all_program_units ../../gcc/fortran/parse.c:5977 0x5e70b2 gfc_parse_file() ../../gcc/fortran/parse.c:6224 0x629da2 gfc_be_parse_file ../../gcc/fortran/f95-lang.c:202 Andreas. -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5 "And now for something completely different."
On Sat, Dec 03, 2016 at 05:58:02PM +0100, Andreas Schwab wrote: > On Dez 01 2016, Steve Kargl <sgk@troutmask.apl.washington.edu> wrote: > > > PR fortran/78618 > > * gfortran.dg/char_conversion.f90: New test. > > That test still crashes the compiler on m68k: > > 0xb40a7f crash_signal > ../../gcc/toplev.c:333 > 0x58dd52 gfc_is_constant_expr(gfc_expr*) > ../../gcc/fortran/expr.c:899 > 0x5feb90 resolve_fl_procedure > ../../gcc/fortran/resolve.c:12013 Yes, we know. I've reopen the PR; see audit trail. It seems to be a used-after-freed issue, but I've been unable to track down the issue. -- Steve
Index: gcc/fortran/check.c =================================================================== --- gcc/fortran/check.c (revision 243142) +++ gcc/fortran/check.c (working copy) @@ -3667,7 +3667,7 @@ gfc_check_range (gfc_expr *x) bool -gfc_check_rank (gfc_expr *a ATTRIBUTE_UNUSED) +gfc_check_rank (gfc_expr *a) { /* Any data object is allowed; a "data object" is a "constant (4.1.3), variable (6), or subobject of a constant (2.4.3.2.3)" (F2008, 1.3.45). */ @@ -3676,9 +3676,16 @@ gfc_check_rank (gfc_expr *a ATTRIBUTE_UN /* Functions returning pointers are regarded as variable, cf. F2008, R602. */ if (a->expr_type == EXPR_FUNCTION) - is_variable = a->value.function.esym - ? a->value.function.esym->result->attr.pointer - : a->symtree->n.sym->result->attr.pointer; + { + if (a->value.function.esym) + is_variable = a->value.function.esym->result->attr.pointer; + else if (a->symtree->n.sym->result) + is_variable = a->symtree->n.sym->result->attr.pointer; + else if (a->symtree->n.sym->value) + is_variable = true; + else + gfc_internal_error ("gfc_check_rank(): invalid function result"); + } if (a->expr_type == EXPR_OP || a->expr_type == EXPR_NULL || a->expr_type == EXPR_COMPCALL|| a->expr_type == EXPR_PPC Index: gcc/fortran/simplify.c =================================================================== --- gcc/fortran/simplify.c (revision 243142) +++ gcc/fortran/simplify.c (working copy) @@ -7148,7 +7148,7 @@ gfc_convert_char_constant (gfc_expr *e, if (!gfc_check_character_range (result->value.character.string[i], kind)) { - gfc_error ("Character %qs in string at %L cannot be converted " + gfc_error_now ("Character %qs in string at %L cannot be converted " "into character kind %d", gfc_print_wide_char (result->value.character.string[i]), &e->where, kind); Index: gcc/testsuite/gfortran.dg/char_conversion.f90 =================================================================== --- gcc/testsuite/gfortran.dg/char_conversion.f90 (nonexistent) +++ gcc/testsuite/gfortran.dg/char_conversion.f90 (working copy) @@ -0,0 +1,6 @@ +! { dg-do compile } +! PR fortran/78618 +program p + character, parameter :: c = char(256,4) ! { dg-error "cannot be converted" } + if (rank(c) /= 0) call abort +end