From 8172c323183ec161364a854cb803bec1e2c82844 Mon Sep 17 00:00:00 2001
From: Eric Christopher <echristo@apple.com>
Date: Fri, 21 Sep 2012 23:03:29 +0000
Subject: [PATCH] Add an --enable-backtraces option to configure to determine
 whether or not we want to print out backtrace information. Useful for
 libraries that don't need backtrace information on a crash.

rdar://11844710

llvm-svn: 164426
---
 autoconf/configure.ac           | 15 +++++++++++++++
 configure                       | 29 ++++++++++++++++++++++++++++-
 include/llvm/Config/config.h.in |  3 +++
 lib/Support/Unix/Signals.inc    |  2 +-
 4 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/autoconf/configure.ac b/autoconf/configure.ac
index 7fa883e9cc5..2f381fec7fd 100644
--- a/autoconf/configure.ac
+++ b/autoconf/configure.ac
@@ -678,6 +678,21 @@ esac
 AC_DEFINE_UNQUOTED([ENABLE_TIMESTAMPS],$ENABLE_TIMESTAMPS,
                    [Define if timestamp information (e.g., __DATE__) is allowed])
 
+dnl Enable embedding timestamp information into build.
+
+AC_ARG_ENABLE(backtraces,
+  AS_HELP_STRING([--enable-backtraces],
+                 [Enable embedding backtraces on crash (default is YES)]),,
+                 enableval=default)
+case "$enableval" in
+  yes) AC_SUBST(ENABLE_TIMESTAMPS,[1]) ;;
+  no)  AC_SUBST(ENABLE_TIMESTAMPS,[0]) ;;
+  default) AC_SUBST(ENABLE_TIMESTAMPS,[1]) ;;
+  *) AC_MSG_ERROR([Invalid setting for --enable-backtraces. Use "yes" or "no"]) ;;
+esac
+AC_DEFINE_UNQUOTED([ENABLE_BACKTRACES],$ENABLE_BACKTRACES,
+                   [Define if you want backtraces on crash])
+
 dnl Allow specific targets to be specified for building (or not)
 TARGETS_TO_BUILD=""
 AC_ARG_ENABLE([targets],AS_HELP_STRING([--enable-targets],
diff --git a/configure b/configure
index 6fbc47c72a7..2bbfe59108b 100755
--- a/configure
+++ b/configure
@@ -1423,6 +1423,8 @@ Optional Features:
                           Win32 DLL (default is NO)
   --enable-timestamps     Enable embedding timestamp information in build
                           (default is YES)
+  --enable-backtraces     Enable embedding backtraces on crash (default is
+                          YES)
   --enable-targets        Build specific host targets: all or
                           target1,target2,... Valid targets are: host, x86,
                           x86_64, sparc, powerpc, arm, mips, spu, hexagon,
@@ -5382,6 +5384,31 @@ cat >>confdefs.h <<_ACEOF
 _ACEOF
 
 
+
+# Check whether --enable-backtraces was given.
+if test "${enable_backtraces+set}" = set; then
+  enableval=$enable_backtraces;
+else
+  enableval=default
+fi
+
+case "$enableval" in
+  yes) ENABLE_TIMESTAMPS=1
+ ;;
+  no)  ENABLE_TIMESTAMPS=0
+ ;;
+  default) ENABLE_TIMESTAMPS=1
+ ;;
+  *) { { echo "$as_me:$LINENO: error: Invalid setting for --enable-backtraces. Use \"yes\" or \"no\"" >&5
+echo "$as_me: error: Invalid setting for --enable-backtraces. Use \"yes\" or \"no\"" >&2;}
+   { (exit 1); exit 1; }; } ;;
+esac
+
+cat >>confdefs.h <<_ACEOF
+#define ENABLE_BACKTRACES $ENABLE_BACKTRACES
+_ACEOF
+
+
 TARGETS_TO_BUILD=""
 # Check whether --enable-targets was given.
 if test "${enable_targets+set}" = set; then
@@ -10289,7 +10316,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<EOF
-#line 10292 "configure"
+#line 10319 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
diff --git a/include/llvm/Config/config.h.in b/include/llvm/Config/config.h.in
index 5a60ba565f0..a4f8af4db02 100644
--- a/include/llvm/Config/config.h.in
+++ b/include/llvm/Config/config.h.in
@@ -18,6 +18,9 @@
 /* Default <path> to all compiler invocations for --sysroot=<path>. */
 #undef DEFAULT_SYSROOT
 
+/* Define if you want backtraces on crash */
+#undef ENABLE_BACKTRACES
+
 /* Define if position independent code is enabled */
 #undef ENABLE_PIC
 
diff --git a/lib/Support/Unix/Signals.inc b/lib/Support/Unix/Signals.inc
index b7f83b6ff73..7d161a6a056 100644
--- a/lib/Support/Unix/Signals.inc
+++ b/lib/Support/Unix/Signals.inc
@@ -243,7 +243,7 @@ void llvm::sys::AddSignalHandler(void (*FnPtr)(void *), void *Cookie) {
 // On glibc systems we have the 'backtrace' function, which works nicely, but
 // doesn't demangle symbols.
 static void PrintStackTrace(void *) {
-#ifdef HAVE_BACKTRACE
+#if defined(HAVE_BACKTRACE) && defined(ENABLE_BACKTRACE)
   static void* StackTrace[256];
   // Use backtrace() to output a backtrace on Linux systems with glibc.
   int depth = backtrace(StackTrace,