Message ID | trinity-0b93b95f-1029-4d2f-96ce-d7b771002d9d-1631472014438@3c-app-gmx-bs61 |
---|---|
State | New |
Headers | show |
Series | PR fortran/85130 - Handling of substring range | expand |
Dear Harald, hi all, On 12.09.21 20:40, Harald Anlauf via Fortran wrote: > in find_substring_ref we erroneously handled given substring start and end > indices as unsigned integers. However, gives indices could be negative, > which is legal as long as end < start, leading to a string of length zero. > The current behavior could lead to a wrong length as well as an invalid read > from (compiler) memory. > > The fix allows to reintroduce code in testcase substr_6.f90 that was > erroneously considered as illegal. > > Regtested on x86_64-pc-linux-gnu. OK for mainline? > As this is invalid code, I'd like to backport this fix. OK to both – thanks for patch and all your recent patch work! Tobias > Fortran - fix handling of substring start and end indices > > gcc/fortran/ChangeLog: > > PR fortran/85130 > * expr.c (find_substring_ref): Handle given substring start and > end indices as signed integers, not unsigned. > > gcc/testsuite/ChangeLog: > > PR fortran/85130 > * gfortran.dg/substr_6.f90: Revert commit r8-7574, adding again > test that was erroneously considered as illegal. > ----------------- Siemens Electronic Design Automation GmbH; Anschrift: Arnulfstraße 201, 80634 München; Gesellschaft mit beschränkter Haftung; Geschäftsführer: Thomas Heurung, Frank Thürauf; Sitz der Gesellschaft: München; Registergericht München, HRB 106955
diff --git a/gcc/fortran/expr.c b/gcc/fortran/expr.c index dfecc3012e1..604e63e6164 100644 --- a/gcc/fortran/expr.c +++ b/gcc/fortran/expr.c @@ -1724,8 +1724,8 @@ find_substring_ref (gfc_expr *p, gfc_expr **newp) *newp = gfc_copy_expr (p); free ((*newp)->value.character.string); - end = (gfc_charlen_t) mpz_get_ui (p->ref->u.ss.end->value.integer); - start = (gfc_charlen_t) mpz_get_ui (p->ref->u.ss.start->value.integer); + end = (gfc_charlen_t) mpz_get_si (p->ref->u.ss.end->value.integer); + start = (gfc_charlen_t) mpz_get_si (p->ref->u.ss.start->value.integer); if (end >= start) length = end - start + 1; else diff --git a/gcc/testsuite/gfortran.dg/substr_6.f90 b/gcc/testsuite/gfortran.dg/substr_6.f90 index 0d5e3d75e88..83e788a55a6 100644 --- a/gcc/testsuite/gfortran.dg/substr_6.f90 +++ b/gcc/testsuite/gfortran.dg/substr_6.f90 @@ -6,6 +6,8 @@ CHARACTER(5), parameter :: c0(1) = (/ "123" // ACHAR(0) // "5" /) CHARACTER*5 c(1) CHARACTER(1), parameter :: c1(5) = (/ "1", "2", "3", ACHAR(0), "5" /) +c = c0(1)(-5:-8) +if (c(1) /= " ") STOP 1 c = (/ c0(1)(1:5) /) do i=1,5 if (c(1)(i:i) /= c1(i)) STOP 2