Refactor exception handling for deoptimization

This CL refactors the exception handling (on the quick side) by isolating the
search of catch handler and the preparation of deoptimization.

We rename the CatchFinder class to QuickExceptionHandler so it's less specific
to catch handler search.

Finding catch handler happens in QuickExceptionHandler::FindCatch. Since the
CatchBlockStackVisitor resolves exception types, it may cause thread suspension
and breaks the assertion current thread can't be suspended. Therefore, we place
the exception in a SirtRef (while it is detached from the current thread) and
remove the thread suspension assertion.

Deoptimization now happens in QuickExceptionHandler::DeoptimizeStack. It uses
the new DeoptimizeStackVisitor class to create shadow frames.

We also add the Thread::GetDeoptimizationException method to get the definition
of the fake exception in only one place.

Change-Id: I01b19fa72af64329b5c3b6c7f0c3339d2d724978

1 files changed, 11 insertions, 7 deletions

diff --git a/runtime/thread.cc b/runtime/thread.cc
index 998579d..095404f 100644
--- a/runtime/thread.cc
+++ b/runtime/thread.cc
@@ -32,7 +32,6 @@
 
 #include "arch/context.h"
 #include "base/mutex.h"
-#include "catch_finder.h"
 #include "class_linker.h"
 #include "class_linker-inl.h"
 #include "cutils/atomic.h"
@@ -54,6 +53,7 @@
 #include "mirror/stack_trace_element.h"
 #include "monitor.h"
 #include "object_utils.h"
+#include "quick_exception_handler.h"
 #include "reflection.h"
 #include "runtime.h"
 #include "scoped_thread_state_change.h"
@@ -1841,7 +1841,7 @@ void Thread::QuickDeliverException() {
   // Don't leave exception visible while we try to find the handler, which may cause class
   // resolution.
   ClearException();
-  bool is_deoptimization = (exception == reinterpret_cast<mirror::Throwable*>(-1));
+  bool is_deoptimization = (exception == GetDeoptimizationException());
   if (kDebugExceptionDelivery) {
     if (!is_deoptimization) {
       mirror::String* msg = exception->GetDetailMessage();
@@ -1852,10 +1852,14 @@ void Thread::QuickDeliverException() {
       DumpStack(LOG(INFO) << "Deoptimizing: ");
     }
   }
-  CatchFinder catch_finder(this, throw_location, exception, is_deoptimization);
-  catch_finder.FindCatch();
-  catch_finder.UpdateInstrumentationStack();
-  catch_finder.DoLongJump();
+  QuickExceptionHandler exception_handler(this, is_deoptimization);
+  if (is_deoptimization) {
+    exception_handler.DeoptimizeStack();
+  } else {
+    exception_handler.FindCatch(throw_location, exception);
+  }
+  exception_handler.UpdateInstrumentationStack();
+  exception_handler.DoLongJump();
   LOG(FATAL) << "UNREACHABLE";
 }
 
@@ -2060,7 +2064,7 @@ void Thread::VisitRoots(RootCallback* visitor, void* arg) {
   if (tlsPtr_.opeer != nullptr) {
     visitor(&tlsPtr_.opeer, arg, thread_id, kRootThreadObject);
   }
-  if (tlsPtr_.exception != nullptr) {
+  if (tlsPtr_.exception != nullptr && tlsPtr_.exception != GetDeoptimizationException()) {
     visitor(reinterpret_cast<mirror::Object**>(&tlsPtr_.exception), arg, thread_id, kRootNativeStack);
   }
   tlsPtr_.throw_location.VisitRoots(visitor, arg);