New --enable-threading configure option to control use of threads in GDB/GDBserver

Add the --enable-threading configure option so multithreading can be disabled at configure time. This is useful for statically-linked builds of GDB/GDBserver, since the thread library doesn't play well with that setup. If you try to run a statically-linked GDB built with threading, it will crash when setting up the number of worker threads. This new option is also convenient when debugging GDB in a system with lots of threads, where the thread discovery code in GDB will emit too many messages, like so: [New Thread 0xfffff74d3a50 (LWP 2625599)] If you have X threads, that message will be repeated X times. The default for --enable-threading is "yes".
4 years ago · 261b07488b
5 changed files with 99 additions and 6 deletions
--- a/gdb/NEWS
+++ b/gdb/NEWS
@ -3,6 +3,17 @@

 *** Changes since GDB 11

+* Configure changes
+
+--enable-threading
+
+  Enable or disable multithreaded symbol loading.  This is enabled
+  by default, but passing --disable-threading or --enable-threading=no
+  to configure will disable it.
+
+  Disabling this can cause a performance penalty when there are a lot of
+  symbols to load, but is useful for debugging purposes.
+
 * New commands

 maint set backtrace-on-fatal-signal on|off
--- a/gdb/configure
+++ b/gdb/configure
@ -910,6 +910,7 @@ with_python
 with_python_libdir
 with_guile
 enable_source_highlight
+enable_threading
 with_intel_pt
 with_libipt_prefix
 with_libipt_type
@ -1597,6 +1598,8 @@ Optional Features:
  --disable-rpath         do not hardcode runtime library paths
  --enable-source-highlight
                          enable source-highlight for source listings
+  --enable-threading      include support for parallel processing of data
+                          (yes/no)
  --enable-werror         treat compile warnings as errors
  --enable-build-warnings enable build-time compiler warnings if gcc is used
  --enable-gdb-build-warnings
@ -14065,6 +14068,22 @@ fi
 done


+  # ----------------------- #
+  # Check for threading.    #
+  # ----------------------- #
+
+  # Check whether --enable-threading was given.
+if test "${enable_threading+set}" = set; then :
+  enableval=$enable_threading; case "$enableval" in
+    yes) want_threading=yes ;;
+    no) want_threading=no ;;
+    *) as_fn_error $? "bad value $enableval for threading" "$LINENO" 5 ;;
+    esac
+else
+  want_threading=yes
+fi
+
+
  # Check for std::thread.  This does not work on some platforms, like
  # mingw and DJGPP.
  ac_ext=cpp
@ -14762,10 +14781,13 @@ done
    LIBS="$save_LIBS"
    CXXFLAGS="$save_CXXFLAGS"
  fi
-  if test "$gdb_cv_cxx_std_thread" = "yes"; then
+
+  if test "$want_threading" = "yes"; then
+    if test "$gdb_cv_cxx_std_thread" = "yes"; then

 $as_echo "#define CXX_STD_THREAD 1" >>confdefs.h

+    fi
  fi
  ac_ext=c
 ac_cpp='$CPP $CPPFLAGS'
--- a/gdbserver/configure
+++ b/gdbserver/configure
@ -746,6 +746,7 @@ ac_user_opts='
 enable_option_checking
 enable_maintainer_mode
 enable_largefile
+enable_threading
 with_intel_pt
 with_gnu_ld
 enable_rpath
@ -1396,6 +1397,8 @@ Optional Features:
                          enable make rules and dependencies not useful (and
                          sometimes confusing) to the casual installer
  --disable-largefile     omit support for large files
+  --enable-threading      include support for parallel processing of data
+                          (yes/no)
  --disable-rpath         do not hardcode runtime library paths
  --enable-unit-tests     Enable the inclusion of unit tests when compiling
                          GDB
@ -7264,6 +7267,22 @@ fi
 done


+  # ----------------------- #
+  # Check for threading.    #
+  # ----------------------- #
+
+  # Check whether --enable-threading was given.
+if test "${enable_threading+set}" = set; then :
+  enableval=$enable_threading; case "$enableval" in
+    yes) want_threading=yes ;;
+    no) want_threading=no ;;
+    *) as_fn_error $? "bad value $enableval for threading" "$LINENO" 5 ;;
+    esac
+else
+  want_threading=yes
+fi
+
+
  # Check for std::thread.  This does not work on some platforms, like
  # mingw and DJGPP.
  ac_ext=cpp
@ -7961,10 +7980,13 @@ done
    LIBS="$save_LIBS"
    CXXFLAGS="$save_CXXFLAGS"
  fi
-  if test "$gdb_cv_cxx_std_thread" = "yes"; then
+
+  if test "$want_threading" = "yes"; then
+    if test "$gdb_cv_cxx_std_thread" = "yes"; then

 $as_echo "#define CXX_STD_THREAD 1" >>confdefs.h

+    fi
  fi
  ac_ext=c
 ac_cpp='$CPP $CPPFLAGS'
--- a/gdbsupport/common.m4
+++ b/gdbsupport/common.m4
@ -76,6 +76,19 @@ AC_DEFUN([GDB_AC_COMMON], [
  # Define HAVE_KINFO_GETFILE if kinfo_getfile is available.
  AC_CHECK_FUNCS(kinfo_getfile)

+  # ----------------------- #
+  # Check for threading.    #
+  # ----------------------- #
+
+  AC_ARG_ENABLE(threading,
+    AS_HELP_STRING([--enable-threading], [include support for parallel processing of data (yes/no)]),
+    [case "$enableval" in
+    yes) want_threading=yes ;;
+    no) want_threading=no ;;
+    *) AC_MSG_ERROR([bad value $enableval for threading]) ;;
+    esac],
+    [want_threading=yes])
+
  # Check for std::thread.  This does not work on some platforms, like
  # mingw and DJGPP.
  AC_LANG_PUSH([C++])
@ -101,9 +114,12 @@ AC_DEFUN([GDB_AC_COMMON], [
    LIBS="$save_LIBS"
    CXXFLAGS="$save_CXXFLAGS"
  fi
-  if test "$gdb_cv_cxx_std_thread" = "yes"; then
-    AC_DEFINE(CXX_STD_THREAD, 1,
-	      [Define to 1 if std::thread works.])
+
+  if test "$want_threading" = "yes"; then
+    if test "$gdb_cv_cxx_std_thread" = "yes"; then
+      AC_DEFINE(CXX_STD_THREAD, 1,
+		[Define to 1 if std::thread works.])
+    fi
  fi
  AC_LANG_POP

--- a/gdbsupport/configure
+++ b/gdbsupport/configure
@ -767,6 +767,7 @@ enable_silent_rules
 enable_dependency_tracking
 enable_plugins
 enable_largefile
+enable_threading
 with_intel_pt
 with_gnu_ld
 enable_rpath
@ -1419,6 +1420,8 @@ Optional Features:
                          speeds up one-time build
  --enable-plugins        Enable support for plugins
  --disable-largefile     omit support for large files
+  --enable-threading      include support for parallel processing of data
+                          (yes/no)
  --disable-rpath         do not hardcode runtime library paths
  --enable-unit-tests     Enable the inclusion of unit tests when compiling
                          GDB
@ -8277,6 +8280,22 @@ fi
 done


+  # ----------------------- #
+  # Check for threading.    #
+  # ----------------------- #
+
+  # Check whether --enable-threading was given.
+if test "${enable_threading+set}" = set; then :
+  enableval=$enable_threading; case "$enableval" in
+    yes) want_threading=yes ;;
+    no) want_threading=no ;;
+    *) as_fn_error $? "bad value $enableval for threading" "$LINENO" 5 ;;
+    esac
+else
+  want_threading=yes
+fi
+
+
  # Check for std::thread.  This does not work on some platforms, like
  # mingw and DJGPP.
  ac_ext=cpp
@ -8974,10 +8993,13 @@ done
    LIBS="$save_LIBS"
    CXXFLAGS="$save_CXXFLAGS"
  fi
-  if test "$gdb_cv_cxx_std_thread" = "yes"; then
+
+  if test "$want_threading" = "yes"; then
+    if test "$gdb_cv_cxx_std_thread" = "yes"; then

 $as_echo "#define CXX_STD_THREAD 1" >>confdefs.h

+    fi
  fi
  ac_ext=c
 ac_cpp='$CPP $CPPFLAGS'