From bb510ed7ea82093c924b027489db6f92250a85b3 Mon Sep 17 00:00:00 2001
From: Sergei Trofimovich <slyfox@gentoo.org>
Date: Sat, 12 May 2018 12:56:46 +0100
Subject: [PATCH] gcc/configure.ac: add --disable-systemtap switch

Before the change systemtap probes were enabled
if target headers had sys/sdt.h at ./configure time.

After the change explicitly ask to enable or disable
for probe support and not rely on automagic dependency
discovery.

Bug: https://bugs.gentoo.org/654748
Bug: https://gcc.gnu.org/bugzilla/PR61257
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
---
 gcc/configure    | 34 ++++++++++++++++++++++++++--------
 gcc/configure.ac | 30 ++++++++++++++++++++++--------
 2 files changed, 48 insertions(+), 16 deletions(-)
--- a/gcc/configure
+++ b/gcc/configure
@@ -947,6 +947,7 @@ enable_gnu_unique_object
 enable_linker_build_id
 enable_libssp
 enable_default_ssp
+enable_systemtap
 with_long_double_128
 with_long_double_format
 with_gc
@@ -1689,6 +1690,7 @@ Optional Features:
                           compiler will always pass --build-id to linker
   --enable-libssp         enable linking against libssp
   --enable-default-ssp    enable Stack Smashing Protection as default
+  --disable-systemtap     enable systemtap static probe points [default=auto]
   --enable-maintainer-mode
                           enable make rules and dependencies not useful (and
                           sometimes confusing) to the casual installer
@@ -18449,7 +18451,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 18452 "configure"
+#line 18454 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -18555,7 +18557,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 18558 "configure"
+#line 18560 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -29280,17 +29282,33 @@ fi
 
 # Test for <sys/sdt.h> on the target.
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking sys/sdt.h in the target C library" >&5
+
+# Check whether --enable-systemtap was given.
+if test "${enable_systemtap+set}" = set; then :
+  enableval=$enable_systemtap; enable_systemtap=$enableval
+else
+  enable_systemtap=auto
+fi
+
+
+if test x$enable_systemtap != xno; then
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking sys/sdt.h in the target C library" >&5
 $as_echo_n "checking sys/sdt.h in the target C library... " >&6; }
-have_sys_sdt_h=no
-if test -f $target_header_dir/sys/sdt.h; then
-  have_sys_sdt_h=yes
+  have_sys_sdt_h=no
+  if test -f $target_header_dir/sys/sdt.h ; then
+    have_sys_sdt_h=yes
 
 $as_echo "#define HAVE_SYS_SDT_H 1" >>confdefs.h
 
-fi
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $have_sys_sdt_h" >&5
+  fi
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $have_sys_sdt_h" >&5
 $as_echo "$have_sys_sdt_h" >&6; }
+  if test x$enable_systemtap = xyes ; then
+    if test x$have_sys_sdt_h = xno ; then
+      as_fn_error "sys/sdt.h was not found" "$LINENO" 5
+    fi
+  fi
+fi
 
 # Check if TFmode long double should be used by default or not.
 # Some glibc targets used DFmode long double, but with glibc 2.4
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -5947,14 +5947,28 @@ AC_SUBST([enable_default_ssp])
 
 # Test for <sys/sdt.h> on the target.
 GCC_TARGET_TEMPLATE([HAVE_SYS_SDT_H])
-AC_MSG_CHECKING(sys/sdt.h in the target C library)
-have_sys_sdt_h=no
-if test -f $target_header_dir/sys/sdt.h; then
-  have_sys_sdt_h=yes
-  AC_DEFINE(HAVE_SYS_SDT_H, 1,
-            [Define if your target C library provides sys/sdt.h])
-fi
-AC_MSG_RESULT($have_sys_sdt_h)
+
+AC_ARG_ENABLE(systemtap,
+[AS_HELP_STRING([--disable-systemtap],
+  [enable systemtap static probe points [default=auto]])],
+      enable_systemtap=$enableval,
+      enable_systemtap=auto)
+
+if test x$enable_systemtap != xno; then
+  AC_MSG_CHECKING(sys/sdt.h in the target C library)
+  have_sys_sdt_h=no
+  if test -f $target_header_dir/sys/sdt.h ; then
+    have_sys_sdt_h=yes
+    AC_DEFINE(HAVE_SYS_SDT_H, 1,
+              [Define if your target C library provides sys/sdt.h])
+  fi
+  AC_MSG_RESULT($have_sys_sdt_h)
+  if test x$enable_systemtap = xyes ; then
+    if test x$have_sys_sdt_h = xno ; then
+      AC_MSG_ERROR([sys/sdt.h was not found])
+    fi
+  fi
+fi
 
 # Check if TFmode long double should be used by default or not.
 # Some glibc targets used DFmode long double, but with glibc 2.4
-- 
2.17.0