[PATCH 1/2] analyzer: gfortran testsuite support

[David Malcolm <dmalcolm@redhat.com>]

PR analyzer/93405 reports an ICE when attempting to use -fanalyzer on
certain gfortran code.  The second patch in this kit fixes that, but
in the meantime I need somewhere to put regression tests for -fanalyzer
with gfortran.

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.  These work, though there are some issues
with the output:
(a) the double-free is reported as:
	Warning: double-‘free’ of ‘_1’
 rather than:
	Warning: double-‘free’ of ‘ptr_x’

(b) the default output format for diagnostic paths is
	-fdiagnostics-path-format=inline-events
but the various events in the path all have column == 0, and
the path-printing doesn't do a good job of that (the event descriptions
don't show up)
With -fdiagnostics-path-format=separate-events, the output looks like:

../../src/gcc/testsuite/gfortran.dg/analyzer/malloc.f90:18:0:

   18 |   call free(ptr_x) ! { dg-warning "double-'free'" }
      |
Warning: double-‘free’ of ‘_1’ [CWE-415] [-Wanalyzer-double-free]
../../src/gcc/testsuite/gfortran.dg/analyzer/malloc.f90:16:0:

   16 |   ptr_x = malloc(20*8)
      |
note: (1) allocated here
../../src/gcc/testsuite/gfortran.dg/analyzer/malloc.f90:17:0:

   17 |   call free(ptr_x)
      |
note: (2) first ‘free’ here
../../src/gcc/testsuite/gfortran.dg/analyzer/malloc.f90:18:0:

   18 |   call free(ptr_x) ! { dg-warning "double-'free'" }
      |
note: (3) second ‘free’ here; first ‘free’ was at (2)

In any case, is this OK for master? (as a place to put such tests, and
do the tests look sane?  I'm not an expert at Fortran, sorry).

Successfully tested on x86_64-pc-linux-gnu; the combination of the
two patches add 6 PASS results to gfortran.sum

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.
---
 .../gfortran.dg/analyzer/analyzer.exp         | 55 +++++++++++++++++++
 .../gfortran.dg/analyzer/malloc-example.f90   | 21 +++++++
 gcc/testsuite/gfortran.dg/analyzer/malloc.f90 | 19 +++++++
 3 files changed, 95 insertions(+)
 create mode 100644 gcc/testsuite/gfortran.dg/analyzer/analyzer.exp
 create mode 100644 gcc/testsuite/gfortran.dg/analyzer/malloc-example.f90
 create mode 100644 gcc/testsuite/gfortran.dg/analyzer/malloc.f90

diff --git a/gcc/testsuite/gfortran.dg/analyzer/analyzer.exp b/gcc/testsuite/gfortran.dg/analyzer/analyzer.exp
new file mode 100644
index 00000000000..00edfa54dce
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/analyzer/analyzer.exp
@@ -0,0 +1,55 @@
+#  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
+}
diff --git a/gcc/testsuite/gfortran.dg/analyzer/malloc-example.f90 b/gcc/testsuite/gfortran.dg/analyzer/malloc-example.f90
new file mode 100644
index 00000000000..4c48d415e05
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/analyzer/malloc-example.f90
@@ -0,0 +1,21 @@
+! 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
diff --git a/gcc/testsuite/gfortran.dg/analyzer/malloc.f90 b/gcc/testsuite/gfortran.dg/analyzer/malloc.f90
new file mode 100644
index 00000000000..05a0bcc3a53
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/analyzer/malloc.f90
@@ -0,0 +1,19 @@
+! { 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" }
-- 
2.21.0