Merge "Refactor exception handling for deoptimization"

1 files changed, 141 insertions, 0 deletions

diff --git a/runtime/quick_exception_handler.cc b/runtime/quick_exception_handler.cc
new file mode 100644
index 0000000000..d5844b6e83
--- /dev/null
+++ b/runtime/quick_exception_handler.cc
@@ -0,0 +1,141 @@
+/*
+ * 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.
+ */
+
+#include "quick_exception_handler.h"
+
+#include "catch_block_stack_visitor.h"
+#include "deoptimize_stack_visitor.h"
+#include "entrypoints/entrypoint_utils.h"
+#include "sirt_ref-inl.h"
+
+namespace art {
+
+QuickExceptionHandler::QuickExceptionHandler(Thread* self, bool is_deoptimization)
+  : self_(self), context_(self->GetLongJumpContext()), is_deoptimization_(is_deoptimization),
+    method_tracing_active_(is_deoptimization ||
+                           Runtime::Current()->GetInstrumentation()->AreExitStubsInstalled()),
+    handler_quick_frame_(nullptr), handler_quick_frame_pc_(0), handler_dex_pc_(0),
+    clear_exception_(false), top_shadow_frame_(nullptr), handler_frame_id_(kInvalidFrameId) {
+}
+
+void QuickExceptionHandler::FindCatch(const ThrowLocation& throw_location,
+                                      mirror::Throwable* exception) {
+  DCHECK(!is_deoptimization_);
+  SirtRef<mirror::Throwable> exception_ref(self_, exception);
+
+  // Walk the stack to find catch handler or prepare for deoptimization.
+  CatchBlockStackVisitor visitor(self_, context_, exception_ref, this);
+  visitor.WalkStack(true);
+
+  mirror::ArtMethod* catch_method = *handler_quick_frame_;
+  if (kDebugExceptionDelivery) {
+    if (catch_method == nullptr) {
+      LOG(INFO) << "Handler is upcall";
+    } else {
+      const DexFile& dex_file = *catch_method->GetDeclaringClass()->GetDexCache()->GetDexFile();
+      int line_number = dex_file.GetLineNumFromPC(catch_method, handler_dex_pc_);
+      LOG(INFO) << "Handler: " << PrettyMethod(catch_method) << " (line: " << line_number << ")";
+    }
+  }
+  if (clear_exception_) {
+    // Exception was cleared as part of delivery.
+    DCHECK(!self_->IsExceptionPending());
+  } else {
+    // Put exception back in root set with clear throw location.
+    self_->SetException(ThrowLocation(), exception_ref.get());
+  }
+  // The debugger may suspend this thread and walk its stack. Let's do this before popping
+  // instrumentation frames.
+  instrumentation::Instrumentation* instrumentation = Runtime::Current()->GetInstrumentation();
+  instrumentation->ExceptionCaughtEvent(self_, throw_location, catch_method, handler_dex_pc_,
+                                        exception_ref.get());
+}
+
+void QuickExceptionHandler::DeoptimizeStack() {
+  DCHECK(is_deoptimization_);
+
+  DeoptimizeStackVisitor visitor(self_, context_, this);
+  visitor.WalkStack(true);
+
+  // Restore deoptimization exception
+  self_->SetException(ThrowLocation(), Thread::GetDeoptimizationException());
+}
+
+// Unwinds all instrumentation stack frame prior to catch handler or upcall.
+class InstrumentationStackVisitor : public StackVisitor {
+ public:
+  InstrumentationStackVisitor(Thread* self, bool is_deoptimization, size_t frame_id)
+      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
+      : StackVisitor(self, nullptr),
+        self_(self), frame_id_(frame_id),
+        instrumentation_frames_to_pop_(0) {
+    CHECK_NE(frame_id_, kInvalidFrameId);
+  }
+
+  bool VisitFrame() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
+    size_t current_frame_id = GetFrameId();
+    if (current_frame_id > frame_id_) {
+      CHECK(GetMethod() != nullptr);
+      if (UNLIKELY(GetQuickInstrumentationExitPc() == GetReturnPc())) {
+        ++instrumentation_frames_to_pop_;
+      }
+      return true;
+    } else {
+      // We reached the frame of the catch handler or the upcall.
+      return false;
+    }
+  }
+
+  size_t GetInstrumentationFramesToPop() const {
+    return instrumentation_frames_to_pop_;
+  }
+
+ private:
+  Thread* const self_;
+  const size_t frame_id_;
+  size_t instrumentation_frames_to_pop_;
+
+  DISALLOW_COPY_AND_ASSIGN(InstrumentationStackVisitor);
+};
+
+void QuickExceptionHandler::UpdateInstrumentationStack() {
+  if (method_tracing_active_) {
+    InstrumentationStackVisitor visitor(self_, is_deoptimization_, handler_frame_id_);
+    visitor.WalkStack(true);
+
+    size_t instrumentation_frames_to_pop = visitor.GetInstrumentationFramesToPop();
+    instrumentation::Instrumentation* instrumentation = Runtime::Current()->GetInstrumentation();
+    for (size_t i = 0; i < instrumentation_frames_to_pop; ++i) {
+      instrumentation->PopMethodForUnwind(self_, is_deoptimization_);
+    }
+  }
+}
+
+void QuickExceptionHandler::DoLongJump() {
+  if (is_deoptimization_) {
+    // TODO: proper return value.
+    self_->SetDeoptimizationShadowFrame(top_shadow_frame_);
+  }
+  // Place context back on thread so it will be available when we continue.
+  self_->ReleaseLongJumpContext(context_);
+  context_->SetSP(reinterpret_cast<uintptr_t>(handler_quick_frame_));
+  CHECK_NE(handler_quick_frame_pc_, 0u);
+  context_->SetPC(handler_quick_frame_pc_);
+  context_->SmashCallerSaves();
+  context_->DoLongJump();
+}
+
+}  // namespace art