NonSFI NaCl: Plumb Exception IRT enough for breakpad.

components/nacl/loader/nonsfi/irt_thread.cc

Index: components/nacl/loader/nonsfi/irt_thread.cc
diff --git a/components/nacl/loader/nonsfi/irt_thread.cc b/components/nacl/loader/nonsfi/irt_thread.cc
index 3351bdc48b1dbbfee29eb063a668f6f1c7e102b6..e6303de7f8bc85aed6fef33709e3411784d92c50 100644
--- a/components/nacl/loader/nonsfi/irt_thread.cc
+++ b/components/nacl/loader/nonsfi/irt_thread.cc
@@ -9,6 +9,7 @@
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "components/nacl/loader/nonsfi/irt_interfaces.h"
+#include "native_client/src/trusted/service_runtime/nacl_signal.h"
 
 namespace nacl {
 namespace nonsfi {
@@ -33,6 +34,7 @@ class ScopedPthreadAttrPtr {
 struct ThreadContext {
   void (*start_func)();
   void* thread_ptr;
+  void* signal_stack;
 };
 
 // A thread local pointer to support nacl_irt_tls.
@@ -45,6 +47,10 @@ void* ThreadMain(void *arg) {
   ::scoped_ptr<ThreadContext> context(static_cast<ThreadContext*>(arg));
   g_thread_ptr = context->thread_ptr;
 
+  // NaClLog(4, "Registering alternate signal stack: %p\n",
+  //         context->signal_stack);
+  NaClSignalStackRegister(context->signal_stack);
+
   // Release the memory of context before running start_func.
   void (*start_func)() = context->start_func;
   context.reset();
@@ -72,6 +78,10 @@ int IrtThreadCreate(void (*start_func)(), void* stack, void* thread_ptr) {
   ::scoped_ptr<ThreadContext> context(new ThreadContext);
   context->start_func = start_func;
   context->thread_ptr = thread_ptr;
+  if (!NaClSignalStackAllocate(&context->signal_stack)) {
+    // NaClLog(4, "Failed to allocate alternate stack\n");
+    return error;
+  }
 
   pthread_t tid;
   error = pthread_create(&tid, &attr, ThreadMain, context.get());