Avoid instrumentation stack corruption.
While debugging a throwing exception, we may end up updating instrumentation
stack frame after having already walked the native stack. This leads to not pop
instrumentation frames prior to catch handler (or upcall if exception is not
caught) and get it desynchronized with the native stack.
To solve this issue, we need to walk the stack again after having reporting the
exception to the instrumentation listener (for example: the debugger) which
may push new instrumentation stack frames. However we do it only when we know
instrumentation is enabled to not slow down exception delivery when executing
code without instrumentation.
Here are the main changes:
- Creates InstrumentationStackVisitor to compute the number of instrumentation
frames to pop (previously done in CatchBlockStackVisitor). We only count frames
prior to catch handler (or upcall). Popping instrumentation frames is done
after having reported the exception to the instrumentation listener.
- Updates the CatchBlockStackVisitor to remove instrumentation frame handling
and focus only on finding the catch handler and prepare deoptimization.
- Creates CatchFinder class to control both visitors and do the long jump.
Change-Id: I29b3871403f297bfb8c087e27f1330b002f5d56d
diff --git a/runtime/catch_block_stack_visitor.h b/runtime/catch_block_stack_visitor.h
new file mode 100644
index 0000000..175ad7d
--- /dev/null
+++ b/runtime/catch_block_stack_visitor.h
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ART_RUNTIME_CATCH_BLOCK_STACK_VISITOR_H_
+#define ART_RUNTIME_CATCH_BLOCK_STACK_VISITOR_H_
+
+#include "mirror/throwable.h"
+#include "thread.h"
+
+namespace art {
+class CatchFinder;
+class ThrowLocation;
+
+// Finds catch handler or prepares deoptimization.
+class CatchBlockStackVisitor : public StackVisitor {
+ public:
+ CatchBlockStackVisitor(Thread* self, Context* context, mirror::Throwable* exception,
+ bool is_deoptimization, CatchFinder* catch_finder)
+ SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
+ : StackVisitor(self, context),
+ self_(self), is_deoptimization_(is_deoptimization),
+ to_find_(is_deoptimization ? nullptr : exception->GetClass()),
+ catch_finder_(catch_finder), native_method_count_(0), prev_shadow_frame_(nullptr) {
+ }
+
+ bool VisitFrame() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
+ private:
+ bool HandleTryItems(mirror::ArtMethod* method) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+ bool HandleDeoptimization(mirror::ArtMethod* m) SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
+
+ Thread* const self_;
+ const bool is_deoptimization_;
+ // The type of the exception catch block to find.
+ mirror::Class* const to_find_;
+ CatchFinder* const catch_finder_;
+ // Number of native methods passed in crawl (equates to number of SIRTs to pop)
+ uint32_t native_method_count_;
+ ShadowFrame* prev_shadow_frame_;
+
+ DISALLOW_COPY_AND_ASSIGN(CatchBlockStackVisitor);
+};
+
+} // namespace art
+#endif // ART_RUNTIME_CATCH_BLOCK_STACK_VISITOR_H_