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/*
* 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 "catch_finder.h"
#include "catch_block_stack_visitor.h"
namespace art {
CatchFinder::CatchFinder(Thread* self, const ThrowLocation& throw_location,
mirror::Throwable* exception, bool is_deoptimization)
: self_(self), context_(self->GetLongJumpContext()),
exception_(exception), is_deoptimization_(is_deoptimization), throw_location_(throw_location),
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) {
// Exception not in root sets, can't allow GC.
last_no_assert_suspension_cause_ = self->StartAssertNoThreadSuspension("Finding catch block");
}
void CatchFinder::FindCatch() {
// Walk the stack to find catch handler or prepare for deoptimization.
CatchBlockStackVisitor visitor(self_, context_, exception_, is_deoptimization_, this);
visitor.WalkStack(true);
mirror::ArtMethod* catch_method = *handler_quick_frame_;
if (catch_method == nullptr) {
if (kDebugExceptionDelivery) {
LOG(INFO) << "Handler is upcall";
}
} else {
CHECK(!is_deoptimization_);
if (kDebugExceptionDelivery) {
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_);
}
self_->EndAssertNoThreadSuspension(last_no_assert_suspension_cause_);
// Do instrumentation events after allowing thread suspension again.
if (!is_deoptimization_) {
// 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_);
}
}
// 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 CatchFinder::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 CatchFinder::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
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