Re: [PATCH] c++tools, configury: Configure with C++; test checking status [PR98821].

Jason Merrill via Gcc-patches Wed, 28 Jul 2021 20:00:15 -0700

On 7/20/21 11:21 AM, Iain Sandoe wrote:

Hi Folks,


Following Jakub’s suggestions (on irc) here is a patch that works around
misconfiguration of the c++tools directory present for at least Linux and Darwin
(probably on any platform that does not have typedefs for the inet structs in 
its
  system headers).

This also pulls in tests for the checking configure flags (copied from libcpp) 
and the
implementations of gcc_assert (copied from gcc).  Actually, there’s not much 
original
code here - but the combination is new, of course.

Tested lightly on Linux and Darwin for master w/wout —disable-checking and on
gcc-11 with default (release).  At least the configures now seem to DTRT for 
those.

OK for master and GCC-11.2?
  (if a complete regtest for passes for both)

OK.

thanks
Iain


====

The c++tools configure fragments need to be built with a C++ compiler.

In addition, the stand-alone server uses diagnostic mechanisms in common
with GCC, but needs to define implementations of the asserts and
supporting output functions.

Signed-off-by: Iain Sandoe <i...@sandoe.co.uk>

PR c++/98821 - modules : c++tools configures with CC but code fragments assume 
CXX.

        PR c++/98821

c++tools/ChangeLog:

        * config.h.in: Regenerate.
        * configure: Regenerate.
        * configure.ac: Configure using C++.  Pull logic to
        detect enabled checking modes.
        * server.cc (AI_NUMERICSERV): Define a fallback value.
        (gcc_assert): New.
        (gcc_checking_assert): New.
        (gcc_unreachable): New.
        (fancy_abort): Only build when checking is enabled.

Co-authored-by: Jakub Jelinek <ja...@redhat.com>
---
  c++tools/config.h.in  |  10 +
  c++tools/configure    | 766 +++++++-----------------------------------
  c++tools/configure.ac |  58 ++++
  c++tools/server.cc    |  35 ++
  4 files changed, 228 insertions(+), 641 deletions(-)

diff --git a/c++tools/configure.ac b/c++tools/configure.ac
index 70fcb641db9..cb67dabf191 100644
--- a/c++tools/configure.ac
+++ b/c++tools/configure.ac
@@ -41,6 +41,8 @@ MISSING=`cd $ac_aux_dir && ${PWDCMD-pwd}`/missing
  AC_CHECK_PROGS([AUTOCONF], [autoconf], [$MISSING autoconf])
  AC_CHECK_PROGS([AUTOHEADER], [autoheader], [$MISSING autoheader])

+AC_LANG(C++)

+
  dnl Enabled by default
  AC_MSG_CHECKING([whether to build C++ tools])
    AC_ARG_ENABLE(c++-tools,
@@ -67,6 +69,62 @@ AC_MSG_RESULT([$maintainer_mode])
  test "$maintainer_mode" = yes && MAINTAINER=yes
  AC_SUBST(MAINTAINER)

+# Enable expensive internal checks

+is_release=
+if test -f $srcdir/../gcc/DEV-PHASE \
+   && test x"`cat $srcdir/../gcc/DEV-PHASE`" != xexperimental; then
+  is_release=yes
+fi
+
+AC_ARG_ENABLE(checking,
+[AS_HELP_STRING([[--enable-checking[=LIST]]],
+               [enable expensive run-time checks.  With LIST,
+                enable only specific categories of checks.
+                Categories are: yes,no,all,none,release.
+                Flags are: misc,valgrind or other strings])],
+[ac_checking_flags="${enableval}"],[
+# Determine the default checks.
+if test x$is_release = x ; then
+  ac_checking_flags=yes
+else
+  ac_checking_flags=release
+fi])
+IFS="${IFS=       }"; ac_save_IFS="$IFS"; IFS="$IFS,"
+for check in release $ac_checking_flags
+do
+       case $check in
+       # these set all the flags to specific states
+       yes|all) ac_checking=1 ; ac_assert_checking=1 ; ac_valgrind_checking= ;;
+       no|none) ac_checking= ; ac_assert_checking= ; ac_valgrind_checking= ;;
+       release) ac_checking= ; ac_assert_checking=1 ; ac_valgrind_checking= ;;
+       # these enable particular checks
+       assert) ac_assert_checking=1 ;;
+       misc) ac_checking=1 ;;
+       valgrind) ac_valgrind_checking=1 ;;
+       # accept
+       *) ;;
+       esac
+done
+IFS="$ac_save_IFS"
+
+if test x$ac_checking != x ; then
+  AC_DEFINE(CHECKING_P, 1,
+[Define to 1 if you want more run-time sanity checks.])
+else
+  AC_DEFINE(CHECKING_P, 0)
+fi
+
+if test x$ac_assert_checking != x ; then
+  AC_DEFINE(ENABLE_ASSERT_CHECKING, 1,
+[Define if you want assertions enabled.  This is a cheap check.])
+fi
+
+if test x$ac_valgrind_checking != x ; then
+  AC_DEFINE(ENABLE_VALGRIND_CHECKING, 1,
+[Define if you want to workaround valgrind (a memory checker) warnings about
+ possible memory leaks because of libcpp use of interior pointers.])
+fi
+
  # Check whether --enable-default-pie was given.
  AC_ARG_ENABLE(default-pie,
  [AS_HELP_STRING([--enable-default-pie],
diff --git a/c++tools/server.cc b/c++tools/server.cc
index fae3e78dc5d..3056352e24b 100644
--- a/c++tools/server.cc
+++ b/c++tools/server.cc
@@ -61,6 +61,10 @@ along with GCC; see the file COPYING3.  If not see
  # define gai_strerror(X) ""
  #endif

+#ifndef AI_NUMERICSERV

+#define AI_NUMERICSERV 0
+#endif
+
  #include <getopt.h>

// Select or epoll

@@ -92,6 +96,35 @@ along with GCC; see the file COPYING3.  If not see
  #define DIR_SEPARATOR '/'
  #endif

+/* Imported from libcpp/system.h

+   Use gcc_assert(EXPR) to test invariants.  */
+#if ENABLE_ASSERT_CHECKING || CHECKING_P
+#define gcc_assert(EXPR)                                                \
+   ((void)(!(EXPR) ? fancy_abort (__FILE__, __LINE__, __FUNCTION__), 0 : 0))
+#elif (GCC_VERSION >= 4005)
+#define gcc_assert(EXPR)                                                \
+  ((void)(__builtin_expect (!(EXPR), 0) ? __builtin_unreachable (), 0 : 0))
+#else
+/* Include EXPR, so that unused variable warnings do not occur.  */
+#define gcc_assert(EXPR) ((void)(0 && (EXPR)))
+#endif
+
+#if CHECKING_P
+#define gcc_checking_assert(EXPR) gcc_assert (EXPR)
+#else
+/* N.B.: in release build EXPR is not evaluated.  */
+#define gcc_checking_assert(EXPR) ((void)(0 && (EXPR)))
+#endif
+
+/* Use gcc_unreachable() to mark unreachable locations (like an
+   unreachable default case of a switch.  Do not use gcc_assert(0).  */
+#if (GCC_VERSION >= 4005) && !ENABLE_ASSERT_CHECKING
+#define gcc_unreachable() __builtin_unreachable ()
+#else
+#define gcc_unreachable() (fancy_abort (__FILE__, __LINE__, __FUNCTION__))
+#endif
+
+
  #if NETWORKING
  struct netmask {
    in6_addr addr;
@@ -202,11 +235,13 @@ internal_error (const char *fmt, ...)

/* Hooked to from gcc_assert & gcc_unreachable. */+#if ENABLE_ASSERT_CHECKING || CHECKING_P

  void ATTRIBUTE_NORETURN ATTRIBUTE_COLD
  fancy_abort (const char *file, int line, const char *func)
  {
    internal_error ("in %s, at %s:%d", func, trim_src_file (file), line);
  }
+#endif

/* Exploded on a signal. */

Re: [PATCH] c++tools, configury: Configure with C++; test checking status [PR98821].

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