From: Mikael Morin <mikael@gcc.gnu.org>
Date: Fri, 28 Jan 2022 21:00:57 +0000 (+0100)
Subject: fortran: Unshare associate var charlen [PR104228]
X-Git-Tag: releases/gcc-11.3.0~89
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3b0f715744d7919ee729d370155a68d5fa97cba9;p=thirdparty%2Fgcc.git

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.

	PR fortran/104228

gcc/fortran/ChangeLog:

	* resolve.c (resolve_assoc_var): Also create a new character
	length for non-dummy associate targets.
	* trans-stmt.c (trans_associate_var): Initialize character length
	even if no temporary is used for the associate variable.

gcc/testsuite/ChangeLog:

	* gfortran.dg/asan/associate_58.f90: New test.
	* gfortran.dg/asan/associate_59.f90: New test.

(cherry picked from commit 57da34939703a6e6d3267a0d25d1fb9369d3ac0e)
---

diff --git a/gcc/fortran/resolve.c b/gcc/fortran/resolve.c
index 4edc0b680e59..b45f0bb70f5b 100644
--- a/gcc/fortran/resolve.c
+++ b/gcc/fortran/resolve.c
@@ -9213,7 +9213,6 @@ 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);
diff --git a/gcc/fortran/trans-stmt.c b/gcc/fortran/trans-stmt.c
index d9562d797a9e..0e387bbb4e6d 100644
--- a/gcc/fortran/trans-stmt.c
+++ b/gcc/fortran/trans-stmt.c
@@ -1939,7 +1939,7 @@ 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)
diff --git a/gcc/testsuite/gfortran.dg/asan/associate_58.f90 b/gcc/testsuite/gfortran.dg/asan/associate_58.f90
new file mode 100644
index 000000000000..b5ea75498b7c
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/asan/associate_58.f90
@@ -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
+
diff --git a/gcc/testsuite/gfortran.dg/asan/associate_59.f90 b/gcc/testsuite/gfortran.dg/asan/associate_59.f90
new file mode 100644
index 000000000000..9bfb2bfbafb9
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/asan/associate_59.f90
@@ -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
+