From 5599c404621b2d8ac021c1427aee6e8974572042 Mon Sep 17 00:00:00 2001
From: Markus Metzger <markus.t.metzger@intel.com>
Date: Tue, 28 Jul 2015 15:47:40 +0200
Subject: [PATCH] configure: check for perf_event.h version

Intel(R) Processor Trace support requires a recent linux/perf_event.h header.

When GDB is built on an older system, Intel(R) Processor Trace will not be
available and there is no indication in the configure and build log as to
what went wrong.

Check for a compatible linux/perf_event.h at configure-time.

gdb/
	* configure.ac: Check for PERF_ATTR_SIZE_VER5 in linux/perf_event.h
	* configure: Regenerate.
---
 gdb/ChangeLog    |  5 +++++
 gdb/configure    | 27 ++++++++++++++++++++++++++-
 gdb/configure.ac | 14 ++++++++++++++
 3 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 2f62edd..105ab5a 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2015-08-07  Markus Metzger  <markus.t.metzger@intel.com>
+
+	* configure.ac: Check for PERF_ATTR_SIZE_VER5 in linux/perf_event.h
+	* configure: Regenerate.
+
 2015-08-06  Yaakov Selkowitz  <yselkowi@redhat.com>
 
 	* Makefile.in (LIBICONV): Define.
diff --git a/gdb/configure b/gdb/configure
index 2949817..e420c03 100755
--- a/gdb/configure
+++ b/gdb/configure
@@ -1560,7 +1560,8 @@ Optional Packages:
                           (auto/yes/no/<python-program>)
   --with-guile[=GUILE]    include guile support
                           (auto/yes/no/<guile-version>/<pkg-config-program>)
-  --with-intel-pt         include Intel(R) Processor Trace support (auto/yes/no)
+  --with-intel-pt         include Intel(R) Processor Trace support
+                          (auto/yes/no)
   --with-libipt-prefix[=DIR]  search for libipt in DIR/include and DIR/lib
   --without-libipt-prefix     don't search for libipt in includedir and libdir
   --without-included-regex
@@ -10115,6 +10116,30 @@ if test "${with_intel_pt}" = no; then
 $as_echo "$as_me: WARNING: Intel(R) Processor Trace support disabled; some features may be unavailable." >&2;}
   HAVE_LIBIPT=no
 else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+#include <linux/perf_event.h>
+#ifndef PERF_ATTR_SIZE_VER5
+# error
+#endif
+
+_ACEOF
+if ac_fn_c_try_cpp "$LINENO"; then :
+  perf_event=yes
+else
+  perf_event=no
+fi
+rm -f conftest.err conftest.$ac_ext
+  if test "$perf_event" != yes; then
+    if test "$with_intel_pt" = yes; then
+      as_fn_error "linux/perf_event.h missing or too old" "$LINENO" 5
+    else
+      { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: linux/perf_event.h missing or too old; some features may be unavailable." >&5
+$as_echo "$as_me: WARNING: linux/perf_event.h missing or too old; some features may be unavailable." >&2;}
+    fi
+  fi
+
 
 
 
diff --git a/gdb/configure.ac b/gdb/configure.ac
index 905c27b..16bcd56 100644
--- a/gdb/configure.ac
+++ b/gdb/configure.ac
@@ -1252,6 +1252,20 @@ if test "${with_intel_pt}" = no; then
   AC_MSG_WARN([Intel(R) Processor Trace support disabled; some features may be unavailable.])
   HAVE_LIBIPT=no
 else
+  AC_PREPROC_IFELSE(AC_LANG_SOURCE([[
+#include <linux/perf_event.h>
+#ifndef PERF_ATTR_SIZE_VER5
+# error
+#endif
+  ]]), [perf_event=yes], [perf_event=no])
+  if test "$perf_event" != yes; then
+    if test "$with_intel_pt" = yes; then
+      AC_MSG_ERROR([linux/perf_event.h missing or too old])
+    else
+      AC_MSG_WARN([linux/perf_event.h missing or too old; some features may be unavailable.])
+    fi
+  fi
+
   AC_LIB_HAVE_LINKFLAGS([ipt], [], [#include "intel-pt.h"], [pt_insn_alloc_decoder (0);])
   if test "$HAVE_LIBIPT" != yes; then
     if test "$with_intel_pt" = yes; then
-- 
2.7.4