Add parameter to allow enabling/disabling selftests via configure

This is a follow-up of:

  https://sourceware.org/ml/gdb-patches/2018-08/msg00347.html

Instead of going throttle and always enabling our selftests (even in
non-development builds), this patch is a bit more conservative and
introduces a configure option ("--enable-unit-tests") that allows the
user to choose whether she wants unit tests in the build or not.  Note
that the current behaviour is retained: if no option is provided, GDB
will have selftests included in a development build, and will *not*
have selftests included in a non-development build.

The rationale for having this option is still the same: due to the
many racy testcases and random failures we see when running the GDB
testsuite, it is unfortunately not possible to perform a full test
when one is building a downstream package.  As the Fedora GDB
maintainer and one of the Debian GDB uploaders, I feel like this
situation could be improved by, at least, executing our selftests
after the package has been built.

This patch introduces no regressions to our build.

OK?

gdb/ChangeLog:
2018-10-10  Sergio Durigan Junior  <sergiodj@redhat.com>
	    Simon Marchi <simark@simark.ca>

	* README (`configure' options): Add documentation for new
	"--enable-unit-tests" option.
	* acinclude.m4: Include "selftest.m4".
	* configure: Regenerate.
	* configure.ac: Use "GDB_AC_SELFTEST".
	* maint.c (maintenance_selftest): Update message informing
	that selftests have been disabled.
	(maintenance_info_selftests): Likewise.
	* selftest.m4: New file.

gdb/gdbserver/ChangeLog:
2018-10-10  Sergio Durigan Junior  <sergiodj@redhat.com>
	    Simon Marchi <simark@simark.ca>

	* acinclude.m4: Include "../selftest.m4".
	* configure: Regenerate.
	* configure.ac: Use "GDB_AC_SELFTEST".
	* configure.srv: Use "$enable_unittests" instead of
	"$development" when checking whether unit tests have been
	enabled.
	* server.c (captured_main): Update message informing that
	selftests have been disabled.

gdb/testsuite/ChangeLog:
2018-10-10  Sergio Durigan Junior  <sergiodj@redhat.com>

	* gdb.gdb/unittest.exp: Update expected message informing that
	selftests have been disabled.
	* gdb.server/unittest.exp: Likewise.

squash! Add parameter to allow enabling/disabling selftests via configure

6 files changed, 46 insertions, 8 deletions

diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index da4c24f..27f7ab5 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,3 +1,15 @@
+2018-10-10  Sergio Durigan Junior  <sergiodj@redhat.com>
+	    Simon Marchi <simark@simark.ca>
+
+	* acinclude.m4: Include "../selftest.m4".
+	* configure: Regenerate.
+	* configure.ac: Use "GDB_AC_SELFTEST".
+	* configure.srv: Use "$enable_unittests" instead of
+	"$development" when checking whether unit tests have been
+	enabled.
+	* server.c (captured_main): Update message informing that
+	selftests have been disabled.
+
 2018-10-04  Tom Tromey  <tom@tromey.com>
 
 	* configure: Rebuild.
diff --git a/gdb/gdbserver/acinclude.m4 b/gdb/gdbserver/acinclude.m4
index c75d783..fc3e344 100644
--- a/gdb/gdbserver/acinclude.m4
+++ b/gdb/gdbserver/acinclude.m4
@@ -31,6 +31,9 @@ m4_include(../ptrace.m4)
 
 m4_include(../ax_cxx_compile_stdcxx.m4)
 
+dnl For GDB_AC_SELFTEST.
+m4_include(../selftest.m4)
+
 dnl Check for existence of a type $1 in libthread_db.h
 dnl Based on BFD_HAVE_SYS_PROCFS_TYPE in bfd/bfd.m4.
 
diff --git a/gdb/gdbserver/configure b/gdb/gdbserver/configure
index a46b865..1ddbd6b 100755
--- a/gdb/gdbserver/configure
+++ b/gdb/gdbserver/configure
@@ -722,6 +722,7 @@ enable_option_checking
 enable_maintainer_mode
 enable_largefile
 enable_libmcheck
+enable_unit_tests
 with_ust
 with_ust_include
 with_ust_lib
@@ -1367,6 +1368,8 @@ Optional Features:
                           sometimes confusing) to the casual installer
   --disable-largefile     omit support for large files
   --enable-libmcheck      Try linking with -lmcheck if available
+  --enable-unit-tests     Enable the inclusion of unit tests when compiling
+                          GDB
   --enable-werror         treat compile warnings as errors
   --enable-build-warnings enable build-time compiler warnings if gcc is used
   --enable-gdb-build-warnings
@@ -5889,13 +5892,35 @@ fi
   fi
 
 
-if $development; then
-  srv_selftest_objs="common/selftest.o"
+
+# Check whether we will enable the inclusion of unit tests when
+# compiling GDB.
+#
+# The default value of this option changes depending whether we're on
+# development mode (in which case it's "true") or not (in which case
+# it's "false").
+# Check whether --enable-unit-tests was given.
+if test "${enable_unit_tests+set}" = set; then :
+  enableval=$enable_unit_tests; case "${enableval}" in
+  yes)  enable_unittests=true  ;;
+  no)   enable_unittests=false ;;
+  *)    as_fn_error $? "bad value ${enableval} for --{enable,disable}-unit-tests option" "$LINENO" 5 ;;
+esac
+else
+  enable_unittests=$development
+fi
+
+
+if $enable_unittests; then
 
 $as_echo "#define GDB_SELF_TEST 1" >>confdefs.h
 
+
+  srv_selftest_objs="common/selftest.o"
+
 fi
 
+
  case ${build_alias} in
   "") build_noncanonical=${build} ;;
   *) build_noncanonical=${build_alias} ;;
diff --git a/gdb/gdbserver/configure.ac b/gdb/gdbserver/configure.ac
index fa3ca53..f1dfa45 100644
--- a/gdb/gdbserver/configure.ac
+++ b/gdb/gdbserver/configure.ac
@@ -54,11 +54,9 @@ else
 fi
 GDB_AC_LIBMCHECK(${libmcheck_default})
 
-if $development; then
+GDB_AC_SELFTEST([
   srv_selftest_objs="common/selftest.o"
-  AC_DEFINE(GDB_SELF_TEST, 1,
-            [Define if self-testing features should be enabled])
-fi
+])
 
 ACX_NONCANONICAL_TARGET
 ACX_NONCANONICAL_HOST
diff --git a/gdb/gdbserver/configure.srv b/gdb/gdbserver/configure.srv
index 72e6a0d..636d830 100644
--- a/gdb/gdbserver/configure.srv
+++ b/gdb/gdbserver/configure.srv
@@ -24,7 +24,7 @@
 # Default hostio_last_error implementation
 srv_hostio_err_objs="hostio-errno.o"
 
-if $development; then
+if $enable_unittests; then
    srv_i386_linux_regobj="i386-linux.o i386-avx-linux.o i386-avx-avx512-linux.o i386-avx-mpx-avx512-pku-linux.o i386-mpx-linux.o i386-avx-mpx-linux.o i386-mmx-linux.o linux-x86-tdesc-selftest.o"
    srv_amd64_linux_regobj="amd64-linux.o amd64-avx-linux.o amd64-avx-avx512-linux.o amd64-avx-mpx-avx512-pku-linux.o amd64-mpx-linux.o amd64-avx-mpx-linux.o x32-linux.o x32-avx-linux.o x32-avx-avx512-linux.o"
 else
diff --git a/gdb/gdbserver/server.c b/gdb/gdbserver/server.c
index d711c53..4ec3548 100644
--- a/gdb/gdbserver/server.c
+++ b/gdb/gdbserver/server.c
@@ -3790,7 +3790,7 @@ captured_main (int argc, char *argv[])
 #if GDB_SELF_TEST
       selftests::run_tests (selftest_filter);
 #else
-      printf (_("Selftests are not available in a non-development build.\n"));
+      printf (_("Selftests have been disabled for this build.\n"));
 #endif
       throw_quit ("Quit");
     }