analyzer: gfortran testsuite support

This patch adds a gfortran.dg/analyzer subdirectory with an analyzer.exp,
setting DEFAULT_FFLAGS on the tests run within it.

It also adds a couple of simple proof-of-concept tests of e.g. detecting
double-frees from gfortran.

gcc/testsuite/ChangeLog:
	* gfortran.dg/analyzer/analyzer.exp: New subdirectory and .exp
	suite.
	* gfortran.dg/analyzer/malloc-example.f90: New test.
	* gfortran.dg/analyzer/malloc.f90: New test.

gcc/testsuite/ChangeLog

+2020-02-10  David Malcolm  <dmalcolm@redhat.com>
+
+	* gfortran.dg/analyzer/analyzer.exp: New subdirectory and .exp
+	suite.
+	* gfortran.dg/analyzer/malloc-example.f90: New test.
+	* gfortran.dg/analyzer/malloc.f90: New test.
+
 2020-02-10  Martin Sebor  <msebor@redhat.com>
 
 	PR c/93640

gcc/testsuite/gfortran.dg/analyzer/analyzer.exp

+#  Copyright (C) 2020 Free Software Foundation, Inc.
+
+#  This file is part of GCC.
+#
+#  GCC is free software; you can redistribute it and/or modify it under
+#  the terms of the GNU General Public License as published by the Free
+#  Software Foundation; either version 3, or (at your option) any later
+#  version.
+#
+#  GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+#  WARRANTY; without even the implied warranty of MERCHANTABILITY or
+#  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+#  for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with GCC; see the file COPYING3.  If not see
+#  <http://www.gnu.org/licenses/>.
+
+# GCC testsuite that uses the `dg.exp' driver.
+
+# Load support procs.
+load_lib gfortran-dg.exp
+load_lib gfortran.exp
+
+# If the analyzer has not been enabled, bail.
+if { ![check_effective_target_analyzer] } {
+    return
+}
+
+global DEFAULT_FFLAGS
+if [info exists DEFAULT_FFLAGS] then {
+  set save_default_fflags $DEFAULT_FFLAGS
+}
+
+# If a testcase doesn't have special options, use these.
+set DEFAULT_FFLAGS "-fanalyzer -fdiagnostics-path-format=separate-events -Wanalyzer-too-complex -fanalyzer-call-summaries"
+
+# Initialize `dg'.
+dg-init
+
+# Main loop.
+
+gfortran_init
+
+gfortran-dg-runtest [lsort \
+       [glob -nocomplain $srcdir/$subdir/*.\[fF\]{,90,95,03,08} ] ] "" $DEFAULT_FFLAGS
+
+# All done.
+dg-finish
+
+if [info exists save_default_fflags] {
+  set DEFAULT_FFLAGS $save_default_fflags
+} else {
+  unset DEFAULT_FFLAGS
+}

gcc/testsuite/gfortran.dg/analyzer/malloc-example.f90

+! Example from GCC documentation
+! { dg-do compile }
+! { dg-additional-options "-fcray-pointer" }
+
+program test_malloc
+  implicit none
+  integer i
+  real*8 x(*), z
+  pointer(ptr_x,x)
+
+  ptr_x = malloc(20*8)
+  do i = 1, 20
+    x(i) = sqrt(1.0d0 / i)
+  end do
+  z = 0
+  do i = 1, 20
+    z = z + x(i)
+    print *, z
+  end do
+  call free(ptr_x)
+end program test_malloc

gcc/testsuite/gfortran.dg/analyzer/malloc.f90

+! { dg-do compile }
+! { dg-additional-options "-fcray-pointer -O0" }
+
+subroutine test_ok
+  real*8 x(*)
+  pointer(ptr_x,x)
+
+  ptr_x = malloc(20*8)
+  call free(ptr_x)
+end subroutine test_ok ! { dg-bogus "leak" }
+
+subroutine test_double_free
+  real*8 x(*)
+  pointer(ptr_x,x)
+
+  ptr_x = malloc(20*8)
+  call free(ptr_x)
+  call free(ptr_x) ! { dg-warning "double-'free'" }
+end subroutine test_double_free ! { dg-bogus "leak" }