Add implicit null and stack checks for x86

This adds compiler and runtime changes for x86
implicit checks.  32 bit only.

Both host and target are supported.
By default, on the host, the implicit checks are null pointer and
stack overflow.  Suspend is implemented but not switched on.

Change-Id: I88a609e98d6bf32f283eaa4e6ec8bbf8dc1df78a

2 files changed, 29 insertions, 0 deletions

diff --git a/sigchainlib/Android.mk b/sigchainlib/Android.mk
index 8e25339..20c8cac 100644
--- a/sigchainlib/Android.mk
+++ b/sigchainlib/Android.mk
@@ -28,3 +28,16 @@ LOCAL_SHARED_LIBRARIES := liblog libdl
 LOCAL_ADDITIONAL_DEPENDENCIES := $(LOCAL_PATH)/Android.mk
 LOCAL_ADDITIONAL_DEPENDENCIES += art/build/Android.common_build.mk
 include $(BUILD_SHARED_LIBRARY)
+
+# Build host library.
+include $(CLEAR_VARS)
+LOCAL_CPP_EXTENSION := $(ART_CPP_EXTENSION)
+LOCAL_MODULE_TAGS := optional
+LOCAL_IS_HOST_MODULE := true
+LOCAL_CFLAGS += $(ART_HOST_CFLAGS)
+LOCAL_SRC_FILES := sigchain.cc
+LOCAL_MODULE:= libsigchain
+LOCAL_ADDITIONAL_DEPENDENCIES += $(LOCAL_PATH)/Android.mk
+LOCAL_LDLIBS = -ldl
+LOCAL_MULTILIB := both
+include $(BUILD_HOST_SHARED_LIBRARY)
diff --git a/sigchainlib/sigchain.cc b/sigchainlib/sigchain.cc
index 26e7d31..73cc9eb 100644
--- a/sigchainlib/sigchain.cc
+++ b/sigchainlib/sigchain.cc
@@ -14,7 +14,13 @@
  * limitations under the License.
  */
 
+#ifdef HAVE_ANDROID_OS
 #include <android/log.h>
+#else
+#include <stdarg.h>
+#include <iostream>
+#endif
+
 #include <dlfcn.h>
 #include <signal.h>
 #include <stdio.h>
@@ -67,7 +73,11 @@ static void log(const char* format, ...) {
   va_list ap;
   va_start(ap, format);
   vsnprintf(buf, sizeof(buf), format, ap);
+#ifdef HAVE_ANDROID_OS
   __android_log_write(ANDROID_LOG_ERROR, "libsigchain", buf);
+#else
+  std::cout << buf << "\n";
+#endif
   va_end(ap);
 }
 
@@ -109,10 +119,16 @@ void InvokeUserSignalHandler(int sig, siginfo_t* info, void* context) {
   if ((action.sa_flags & SA_SIGINFO) == 0) {
     if (action.sa_handler != NULL) {
       action.sa_handler(sig);
+    } else {
+       signal(sig, SIG_DFL);
+       raise(sig);
     }
   } else {
     if (action.sa_sigaction != NULL) {
       action.sa_sigaction(sig, info, context);
+    } else {
+       signal(sig, SIG_DFL);
+       raise(sig);
     }
   }
 }