From 0819226560387b2953622ee3d5d051a35606d504 Mon Sep 17 00:00:00 2001
From: Mikael Morin <mikael@gcc.gnu.org>
Date: Fri, 28 Jan 2022 22:00:57 +0100
Subject: [PATCH] fortran: Unshare associate var charlen [PR104228]
PR104228 showed that character lengths were shared between associate
variable and associate targets. This is problematic when the associate
target is itself a variable and gets a variable to hold the length, as
the length variable is added (and all the variables following it in the chain)
to both the associate variable scope and the target variable scope.
This caused an ICE when compiling with -O0 -fsanitize=address.
This change forces the creation of a separate character length for the
associate variable. It also forces the initialization of the character
length variable to avoid regressing associate_32 and associate_47 tests.
gcc/fortran/ChangeLog:
* resolve.cc (resolve_assoc_var): Also create a new character
length for non-dummy associate targets.
* trans-stmt.cc (trans_associate_var): Initialize character length
even if no temporary is used for the associate variable.
gcc/testsuite/ChangeLog:
* gfortran.dg/asan/associate_1.f90: New test.
* gfortran.dg/asan/associate_2.f90: New test.
---
gcc/fortran/resolve.cc | 1 -
gcc/fortran/trans-stmt.cc | 2 +-
.../gfortran.dg/asan/associate_1.f90 | 19 +++++++++++++++++++
.../gfortran.dg/asan/associate_2.f90 | 19 +++++++++++++++++++
4 files changed, 39 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/gfortran.dg/asan/associate_1.f90
create mode 100644 gcc/testsuite/gfortran.dg/asan/associate_2.f90
@@ -9227,7 +9227,6 @@ resolve_assoc_var (gfc_symbol* sym, bool resolve_target)
sym->ts.u.cl = target->ts.u.cl;
if (sym->ts.deferred && target->expr_type == EXPR_VARIABLE
- && target->symtree->n.sym->attr.dummy
&& sym->ts.u.cl == target->ts.u.cl)
{
sym->ts.u.cl = gfc_new_charlen (sym->ns, NULL);
@@ -1918,7 +1918,7 @@ trans_associate_var (gfc_symbol *sym, gfc_wrapped_block *block)
gfc_conv_expr_descriptor (&se, e);
if (sym->ts.type == BT_CHARACTER
- && !se.direct_byref && sym->ts.deferred
+ && sym->ts.deferred
&& !sym->attr.select_type_temporary
&& VAR_P (sym->ts.u.cl->backend_decl)
&& se.string_length != sym->ts.u.cl->backend_decl)
new file mode 100644
@@ -0,0 +1,19 @@
+! { dg-do compile }
+! { dg-additional-options "-O0" }
+!
+! PR fortran/104228
+! The code generated code for the program below wrongly pushed the Y character
+! length variable to both P and S scope, which was leading to an ICE when
+! address sanitizer was in effect
+
+program p
+ character(:), save, allocatable :: x(:)
+ call s
+contains
+ subroutine s
+ associate (y => x)
+ y = [x]
+ end associate
+ end
+end
+
new file mode 100644
@@ -0,0 +1,19 @@
+! { dg-do compile }
+! { dg-additional-options "-O0" }
+!
+! PR fortran/104228
+! The code generated code for the program below wrongly pushed the Y character
+! length variable to both P and S scope, which was leading to an ICE when
+! address sanitizer was in effect
+
+program p
+ character(:), allocatable :: x(:)
+ call s
+contains
+ subroutine s
+ associate (y => x)
+ y = [x]
+ end associate
+ end
+end
+
--
2.34.1