[conf] Add config variable to disable crash related overrides.

 - We do some nasty things w.r.t. installing or overriding signal handlers in
   order to improve our crash recovery support or interaction with crash
   reporting software, and those things are not necessarily appropriate when
   LLVM is being linked into a client application that has its own ideas about
   how to do things. This gives those clients a way to disable that handling at
   build time.

 - Currently, the code this guards is all Apple specific, but other platforms
   might have the same concerns so I went for a more generic configure
   name. Someone who is more familiar with library embedding on Windows can
   handle choosing which of the Windows/Signals.inc behaviors might make sense
   to go under this flag.

 - This also fixes the proper autoconf'ing of ENABLE_BACKTRACES. The code
   expects it to be undefined when disabled, but the autoconf check was just
   defining it to 0.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189694 91177308-0d34-0410-b5e6-96231b3b80d8

CMakeLists.txt

@@ -139,6 +139,11 @@ if(LLVM_ENABLE_BACKTRACES)
   set(ENABLE_BACKTRACES 1)
 endif()
 
+option(LLVM_ENABLE_CRASH_OVERRIDES "Enable crash overrides." ON)
+if(LLVM_ENABLE_CRASH_OVERRIDES)
+  set(ENABLE_CRASH_OVERRIDES 1)
+endif()
+
 option(LLVM_ENABLE_FFI "Use libffi to call external functions from the interpreter" OFF)
 set(FFI_LIBRARY_DIR "" CACHE PATH "Additional directory, where CMake should search for libffi.so")
 set(FFI_INCLUDE_DIR "" CACHE PATH "Additional directory, where CMake should search for ffi.h or ffi/ffi.h")

autoconf/configure.ac

@@ -800,20 +800,37 @@ esac
 AC_DEFINE_UNQUOTED([ENABLE_TIMESTAMPS],$ENABLE_TIMESTAMPS,
                    [Define if timestamp information (e.g., __DATE__) is allowed])
 
-dnl Enable embedding timestamp information into build.
+dnl Enable support for showing backtraces.
+AC_ARG_ENABLE(backtraces, AS_HELP_STRING(
+  [--enable-backtraces],
+  [Enable embedding backtraces on crash (default is YES)]),
+  [case "$enableval" in
+    yes) llvm_cv_enable_backtraces="yes" ;;
+    no)  llvm_cv_enable_backtraces="no"  ;;
+    *) AC_MSG_ERROR([Invalid setting for --enable-backtraces. Use "yes" or "no"]) ;;
+  esac],
+  llvm_cv_enable_backtraces="yes")
+if test "$llvm_cv_enable_backtraces" = "yes" ; then
+  AC_DEFINE([ENABLE_BACKTRACES],[1],
+            [Define if you want backtraces on crash])
+fi
 
-AC_ARG_ENABLE(backtraces,
-  AS_HELP_STRING([--enable-backtraces],
-                 [Enable embedding backtraces on crash (default is YES)]),,
-                 enableval=default)
-case "$enableval" in
-  yes) AC_SUBST(ENABLE_BACKTRACES,[1]) ;;
-  no)  AC_SUBST(ENABLE_BACKTRACES,[0]) ;;
-  default) AC_SUBST(ENABLE_BACKTRACES,[1]) ;;
-  *) AC_MSG_ERROR([Invalid setting for --enable-backtraces. Use "yes" or "no"]) ;;
-esac
-AC_DEFINE_UNQUOTED([ENABLE_BACKTRACES],$ENABLE_BACKTRACES,
-                   [Define if you want backtraces on crash])
+dnl Enable installing platform specific signal handling overrides, for improved
+dnl CrashRecovery support or interaction with crash reporting software. This
+dnl support may be inappropriate for some clients embedding LLVM as a library.
+AC_ARG_ENABLE(crash-overrides, AS_HELP_STRING(
+  [--enable-crash-overrides],
+  [Enable crash handling overrides (default is YES)]),
+  [case "$enableval" in
+    yes) llvm_cv_enable_crash_overrides="yes" ;;
+    no)  llvm_cv_enable_crash_overrides="no"  ;;
+    *) AC_MSG_ERROR([Invalid setting for --enable-crash-overrides. Use "yes" or "no"]) ;;
+  esac],
+  llvm_cv_enable_crash_overrides="yes")
+if test "$llvm_cv_enable_crash_overrides" = "yes" ; then
+  AC_DEFINE([ENABLE_CRASH_OVERRIDES],[1],
+            [Define to enable crash handling overrides])
+fi
 
 dnl Allow specific targets to be specified for building (or not)
 TARGETS_TO_BUILD=""

configure

@@ -709,7 +709,6 @@ ENABLE_PIC
 ENABLE_SHARED
 ENABLE_EMBED_STDCXX
 ENABLE_TIMESTAMPS
-ENABLE_BACKTRACES
 TARGETS_TO_BUILD
 LLVM_ENUM_TARGETS
 LLVM_ENUM_ASM_PRINTERS
@@ -1443,6 +1442,8 @@ Optional Features:
                           (default is YES)
   --enable-backtraces     Enable embedding backtraces on crash (default is
                           YES)
+  --enable-crash-overrides
+                          Enable crash handling overrides (default is YES)
   --enable-targets        Build specific host targets: all or
                           target1,target2,... Valid targets are: host, x86,
                           x86_64, sparc, powerpc, arm, aarch64, mips, hexagon,
@@ -5632,30 +5633,47 @@ cat >>confdefs.h <<_ACEOF
 _ACEOF
 
 
-
 # Check whether --enable-backtraces was given.
 if test "${enable_backtraces+set}" = set; then
-  enableval=$enable_backtraces;
+  enableval=$enable_backtraces; case "$enableval" in
+    yes) llvm_cv_enable_backtraces="yes" ;;
+    no)  llvm_cv_enable_backtraces="no"  ;;
+    *) { { 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
 else
-  enableval=default
+  llvm_cv_enable_backtraces="yes"
 fi
 
-case "$enableval" in
-  yes) ENABLE_BACKTRACES=1
- ;;
-  no)  ENABLE_BACKTRACES=0
- ;;
-  default) ENABLE_BACKTRACES=1
- ;;
-  *) { { echo "$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;}
+if test "$llvm_cv_enable_backtraces" = "yes" ; then
+
+cat >>confdefs.h <<\_ACEOF
+#define ENABLE_BACKTRACES 1
+_ACEOF
+
+fi
+
+# Check whether --enable-crash-overrides was given.
+if test "${enable_crash_overrides+set}" = set; then
+  enableval=$enable_crash_overrides; case "$enableval" in
+    yes) llvm_cv_enable_crash_overrides="yes" ;;
+    no)  llvm_cv_enable_crash_overrides="no"  ;;
+    *) { { echo "$as_me:$LINENO: error: Invalid setting for --enable-crash-overrides. Use \"yes\" or \"no\"" >&5
+echo "$as_me: error: Invalid setting for --enable-crash-overrides. Use \"yes\" or \"no\"" >&2;}
    { (exit 1); exit 1; }; } ;;
-esac
+  esac
+else
+  llvm_cv_enable_crash_overrides="yes"
+fi
 
-cat >>confdefs.h <<_ACEOF
-#define ENABLE_BACKTRACES $ENABLE_BACKTRACES
+if test "$llvm_cv_enable_crash_overrides" = "yes" ; then
+
+cat >>confdefs.h <<\_ACEOF
+#define ENABLE_CRASH_OVERRIDES 1
 _ACEOF
 
+fi
 
 TARGETS_TO_BUILD=""
 # Check whether --enable-targets was given.
@@ -10568,7 +10586,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<EOF
-#line 10571 "configure"
+#line 10589 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -23055,7 +23073,6 @@ ENABLE_PIC!$ENABLE_PIC$ac_delim
 ENABLE_SHARED!$ENABLE_SHARED$ac_delim
 ENABLE_EMBED_STDCXX!$ENABLE_EMBED_STDCXX$ac_delim
 ENABLE_TIMESTAMPS!$ENABLE_TIMESTAMPS$ac_delim
-ENABLE_BACKTRACES!$ENABLE_BACKTRACES$ac_delim
 TARGETS_TO_BUILD!$TARGETS_TO_BUILD$ac_delim
 LLVM_ENUM_TARGETS!$LLVM_ENUM_TARGETS$ac_delim
 LLVM_ENUM_ASM_PRINTERS!$LLVM_ENUM_ASM_PRINTERS$ac_delim
@@ -23142,6 +23159,7 @@ LLVM_MANDIR!$LLVM_MANDIR$ac_delim
 LLVM_CONFIGTIME!$LLVM_CONFIGTIME$ac_delim
 BINDINGS_TO_BUILD!$BINDINGS_TO_BUILD$ac_delim
 ALL_BINDINGS!$ALL_BINDINGS$ac_delim
+OCAML_LIBDIR!$OCAML_LIBDIR$ac_delim
 _ACEOF
 
   if test `sed -n "s/.*$ac_delim\$/X/p" conf$$subs.sed | grep -c X` = 97; then
@@ -23183,7 +23201,6 @@ _ACEOF
 ac_delim='%!_!# '
 for ac_last_try in false false false false false :; do
   cat >conf$$subs.sed <<_ACEOF
-OCAML_LIBDIR!$OCAML_LIBDIR$ac_delim
 ENABLE_VISIBILITY_INLINES_HIDDEN!$ENABLE_VISIBILITY_INLINES_HIDDEN$ac_delim
 RPATH!$RPATH$ac_delim
 RDYNAMIC!$RDYNAMIC$ac_delim
@@ -23192,7 +23209,7 @@ LIBOBJS!$LIBOBJS$ac_delim
 LTLIBOBJS!$LTLIBOBJS$ac_delim
 _ACEOF
 
-  if test `sed -n "s/.*$ac_delim\$/X/p" conf$$subs.sed | grep -c X` = 7; then
+  if test `sed -n "s/.*$ac_delim\$/X/p" conf$$subs.sed | grep -c X` = 6; then
     break
   elif $ac_last_try; then
     { { echo "$as_me:$LINENO: error: could not make $CONFIG_STATUS" >&5

include/llvm/Config/config.h.cmake

@@ -21,6 +21,9 @@
 /* Define if you want backtraces on crash */
 #cmakedefine ENABLE_BACKTRACES
 
+/* Define to enable crash overrides */
+#cmakedefine ENABLE_CRASH_OVERRIDES
+
 /* Define if position independent code is enabled */
 #cmakedefine ENABLE_PIC
 

include/llvm/Config/config.h.in

@@ -21,6 +21,9 @@
 /* Define if you want backtraces on crash */
 #undef ENABLE_BACKTRACES
 
+/* Define to enable crash handling overrides */
+#undef ENABLE_CRASH_OVERRIDES
+
 /* Define if position independent code is enabled */
 #undef ENABLE_PIC
 

lib/Support/Unix/Signals.inc

@@ -333,7 +333,7 @@ static void PrintStackTraceSignalHandler(void *) {
 void llvm::sys::PrintStackTraceOnErrorSignal() {
   AddSignalHandler(PrintStackTraceSignalHandler, 0);
 
-#if defined(__APPLE__)
+#if defined(__APPLE__) && defined(ENABLE_CRASH_OVERRIDES)
   // Environment variable to disable any kind of crash dialog.
   if (getenv("LLVM_DISABLE_CRASH_REPORT")) {
     mach_port_t self = mach_task_self();
@@ -359,7 +359,7 @@ void llvm::sys::PrintStackTraceOnErrorSignal() {
 // the same linkage unit by just defining our own versions of the assert handler
 // and abort.
 
-#ifdef __APPLE__
+#if defined(__APPLE__) && defined(ENABLE_CRASH_OVERRIDES)
 
 #include <signal.h>
 #include <pthread.h>