| Message ID | trinity-447b5aad-73a7-403c-9cb3-1dac18f13b6c-1645046402715@3c-app-gmx-bap59 |
|---|---|
| State | New |
| Headers | show |
| Series | PR fortran/104573 - ICE in resolve_structure_cons, at fortran/resolve.cc:1299 | expand |
Am 16.02.22 um 22:20 schrieb Harald Anlauf via Gcc-patches: > Dear Fortranners, > > while we detect invalid uses of type(*), we may run into other issues > later when the declared variable is used, leading to an ICE due to a > NULL pointer dereference. This is demonstrated by Gerhard's testcase. > > Steve and I came to rather similar fixes, see PR. Mine is attached. > > Regtested on x86_64-pc-linux-gnu. OK for mainline? > > Thanks, > Harald >
Le 16/02/2022 à 22:20, Harald Anlauf via Fortran a écrit : > Dear Fortranners, > > while we detect invalid uses of type(*), we may run into other issues > later when the declared variable is used, leading to an ICE due to a > NULL pointer dereference. This is demonstrated by Gerhard's testcase. > > Steve and I came to rather similar fixes, see PR. Mine is attached. > > Regtested on x86_64-pc-linux-gnu. OK for mainline? > > Thanks, > Harald > > diff --git a/gcc/fortran/resolve.cc b/gcc/fortran/resolve.cc > index 266e41e25b1..2fa1acdbd6d 100644 > --- a/gcc/fortran/resolve.cc > +++ b/gcc/fortran/resolve.cc > @@ -1288,15 +1288,17 @@ resolve_structure_cons (gfc_expr *expr, int init) > } > } > > - cons = gfc_constructor_first (expr->value.constructor); > - > /* A constructor may have references if it is the result of substituting a > parameter variable. In this case we just pull out the component we > want. */ > if (expr->ref) > comp = expr->ref->u.c.sym->components; > - else > + else if (expr->ts.u.derived) > comp = expr->ts.u.derived->components; These unprotected union accesses always make me nervous. I have tried (hard) to exhibit a case not fixed by your patch, and I have found the case below that almost qualifies, except that there is an ICE before anything can happen. With a minor tweak to prevent the ICE, the problem does appear. program p type t integer :: a end type character(3), parameter :: x = t(2) character(3), parameter :: y = x print *, y end In that case the character length information occupies the same space as a derived type symbol; the else-if condition evaluates to true, and everything breaks from there. So please use a condition on expr->ts.type instead. I think the relevant values associated with ts->u.derived are BT_DERIVED, BT_CLASS and BT_UNION. OK with that change. Thanks, and sorry for the time I took before looking at it.
Le 28/02/2022 à 22:32, Mikael Morin a écrit : > So please use a condition on expr->ts.type instead. >I said «instead», but «as well» is more appropriate; both expr.ts.type and expr.ts.u.derived conditions are probably necessary.
From 01d629506edca711f02912e2cc124f8894cfa389 Mon Sep 17 00:00:00 2001 From: Harald Anlauf <anlauf@gmx.de> Date: Wed, 16 Feb 2022 22:13:02 +0100 Subject: [PATCH] Fortran: error recovery after invalid assumed type declaration gcc/fortran/ChangeLog: PR fortran/104573 * resolve.cc (resolve_structure_cons): Avoid NULL pointer dereference when there is no valid component. gcc/testsuite/ChangeLog: PR fortran/104573 * gfortran.dg/assumed_type_14.f90: New test. --- gcc/fortran/resolve.cc | 8 +++++--- gcc/testsuite/gfortran.dg/assumed_type_14.f90 | 12 ++++++++++++ 2 files changed, 17 insertions(+), 3 deletions(-) create mode 100644 gcc/testsuite/gfortran.dg/assumed_type_14.f90 diff --git a/gcc/fortran/resolve.cc b/gcc/fortran/resolve.cc index 266e41e25b1..2fa1acdbd6d 100644 --- a/gcc/fortran/resolve.cc +++ b/gcc/fortran/resolve.cc @@ -1288,15 +1288,17 @@ resolve_structure_cons (gfc_expr *expr, int init) } } - cons = gfc_constructor_first (expr->value.constructor); - /* A constructor may have references if it is the result of substituting a parameter variable. In this case we just pull out the component we want. */ if (expr->ref) comp = expr->ref->u.c.sym->components; - else + else if (expr->ts.u.derived) comp = expr->ts.u.derived->components; + else + return false; + + cons = gfc_constructor_first (expr->value.constructor); for (; comp && cons; comp = comp->next, cons = gfc_constructor_next (cons)) { diff --git a/gcc/testsuite/gfortran.dg/assumed_type_14.f90 b/gcc/testsuite/gfortran.dg/assumed_type_14.f90 new file mode 100644 index 00000000000..6cfe2e4fb73 --- /dev/null +++ b/gcc/testsuite/gfortran.dg/assumed_type_14.f90 @@ -0,0 +1,12 @@ +! { dg-do compile } +! PR fortran/104573 - ICE in resolve_structure_cons +! Contributed by G.Steinmetz + +program p + type t + end type + type(*), parameter :: x = t() ! { dg-error "Assumed type of variable" } + print *, x +end + +! { dg-prune-output "Cannot convert" } -- 2.34.1