blob: db937ad536036cd9acbb028548cca7321106abbc [file] [log] [blame]
// Copyright (c) 2011, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#include "vm/exceptions.h"
#include "platform/address_sanitizer.h"
#include "lib/stacktrace.h"
#include "vm/dart_api_impl.h"
#include "vm/dart_entry.h"
#include "vm/datastream.h"
#include "vm/debugger.h"
#include "vm/deopt_instructions.h"
#include "vm/flags.h"
#include "vm/log.h"
#include "vm/longjump.h"
#include "vm/object.h"
#include "vm/object_store.h"
#include "vm/stack_frame.h"
#include "vm/stub_code.h"
#include "vm/symbols.h"
namespace dart {
DECLARE_FLAG(bool, trace_deoptimization);
DEFINE_FLAG(bool,
print_stacktrace_at_throw,
false,
"Prints a stack trace everytime a throw occurs.");
class StackTraceBuilder : public ValueObject {
public:
StackTraceBuilder() {}
virtual ~StackTraceBuilder() {}
virtual void AddFrame(const Object& code, uword pc_offset) = 0;
};
class PreallocatedStackTraceBuilder : public StackTraceBuilder {
public:
explicit PreallocatedStackTraceBuilder(const Instance& stacktrace)
: stacktrace_(StackTrace::Cast(stacktrace)),
cur_index_(0),
dropped_frames_(0) {
ASSERT(
stacktrace_.ptr() ==
Isolate::Current()->isolate_object_store()->preallocated_stack_trace());
}
~PreallocatedStackTraceBuilder() {}
void AddFrame(const Object& code, uword pc_offset) override;
private:
static const int kNumTopframes = StackTrace::kPreallocatedStackdepth / 2;
const StackTrace& stacktrace_;
intptr_t cur_index_;
intptr_t dropped_frames_;
DISALLOW_COPY_AND_ASSIGN(PreallocatedStackTraceBuilder);
};
void PreallocatedStackTraceBuilder::AddFrame(const Object& code,
uword pc_offset) {
if (cur_index_ >= StackTrace::kPreallocatedStackdepth) {
// The number of frames is overflowing the preallocated stack trace object.
Object& frame_code = Object::Handle();
intptr_t start = StackTrace::kPreallocatedStackdepth - (kNumTopframes - 1);
intptr_t null_slot = start - 2;
// We are going to drop one frame.
dropped_frames_++;
// Add an empty slot to indicate the overflow so that the toString
// method can account for the overflow.
if (stacktrace_.CodeAtFrame(null_slot) != Code::null()) {
stacktrace_.SetCodeAtFrame(null_slot, frame_code);
// We drop an extra frame here too.
dropped_frames_++;
}
// Encode the number of dropped frames into the pc offset.
stacktrace_.SetPcOffsetAtFrame(null_slot, dropped_frames_);
// Move frames one slot down so that we can accommodate the new frame.
for (intptr_t i = start; i < StackTrace::kPreallocatedStackdepth; i++) {
intptr_t prev = (i - 1);
frame_code = stacktrace_.CodeAtFrame(i);
const uword frame_offset = stacktrace_.PcOffsetAtFrame(i);
stacktrace_.SetCodeAtFrame(prev, frame_code);
stacktrace_.SetPcOffsetAtFrame(prev, frame_offset);
}
cur_index_ = (StackTrace::kPreallocatedStackdepth - 1);
}
stacktrace_.SetCodeAtFrame(cur_index_, code);
stacktrace_.SetPcOffsetAtFrame(cur_index_, pc_offset);
cur_index_ += 1;
}
static void BuildStackTrace(StackTraceBuilder* builder) {
StackFrameIterator frames(ValidationPolicy::kDontValidateFrames,
Thread::Current(),
StackFrameIterator::kNoCrossThreadIteration);
StackFrame* frame = frames.NextFrame();
ASSERT(frame != NULL); // We expect to find a dart invocation frame.
Code& code = Code::Handle();
for (; frame != NULL; frame = frames.NextFrame()) {
if (!frame->IsDartFrame()) {
continue;
}
code = frame->LookupDartCode();
ASSERT(code.ContainsInstructionAt(frame->pc()));
const uword pc_offset = frame->pc() - code.PayloadStart();
builder->AddFrame(code, pc_offset);
}
}
class ExceptionHandlerFinder : public StackResource {
public:
explicit ExceptionHandlerFinder(Thread* thread)
: StackResource(thread), thread_(thread) {}
// Iterate through the stack frames and try to find a frame with an
// exception handler. Once found, set the pc, sp and fp so that execution
// can continue in that frame. Sets 'needs_stacktrace' if there is no
// catch-all handler or if a stack-trace is specified in the catch.
bool Find() {
StackFrameIterator frames(ValidationPolicy::kDontValidateFrames,
Thread::Current(),
StackFrameIterator::kNoCrossThreadIteration);
StackFrame* frame = frames.NextFrame();
if (frame == NULL) return false; // No Dart frame.
handler_pc_set_ = false;
needs_stacktrace = false;
bool is_catch_all = false;
uword temp_handler_pc = kUwordMax;
bool is_optimized = false;
code_ = NULL;
catch_entry_moves_cache_ = thread_->isolate()->catch_entry_moves_cache();
while (!frame->IsEntryFrame()) {
if (frame->IsDartFrame()) {
if (frame->FindExceptionHandler(thread_, &temp_handler_pc,
&needs_stacktrace, &is_catch_all,
&is_optimized)) {
if (!handler_pc_set_) {
handler_pc_set_ = true;
handler_pc = temp_handler_pc;
handler_sp = frame->sp();
handler_fp = frame->fp();
if (is_optimized) {
pc_ = frame->pc();
code_ = &Code::Handle(frame->LookupDartCode());
CatchEntryMovesRefPtr* cached_catch_entry_moves =
catch_entry_moves_cache_->Lookup(pc_);
if (cached_catch_entry_moves != NULL) {
cached_catch_entry_moves_ = *cached_catch_entry_moves;
}
if (cached_catch_entry_moves_.IsEmpty()) {
#if defined(DART_PRECOMPILED_RUNTIME)
// Only AOT mode is supported.
ReadCompressedCatchEntryMoves();
#elif defined(DART_PRECOMPILER)
// Both AOT and JIT modes are supported.
if (FLAG_precompiled_mode) {
ReadCompressedCatchEntryMoves();
} else {
GetCatchEntryMovesFromDeopt(code_->num_variables(), frame);
}
#else
// Only JIT mode is supported.
ASSERT(!FLAG_precompiled_mode);
GetCatchEntryMovesFromDeopt(code_->num_variables(), frame);
#endif
}
}
}
if (needs_stacktrace || is_catch_all) {
return true;
}
}
} // if frame->IsDartFrame
frame = frames.NextFrame();
ASSERT(frame != NULL);
} // while !frame->IsEntryFrame
ASSERT(frame->IsEntryFrame());
if (!handler_pc_set_) {
handler_pc = frame->pc();
handler_sp = frame->sp();
handler_fp = frame->fp();
}
// No catch-all encountered, needs stacktrace.
needs_stacktrace = true;
return handler_pc_set_;
}
// When entering catch block in the optimized code we need to execute
// catch entry moves that would morph the state of the frame into
// what catch entry expects.
void PrepareFrameForCatchEntry() {
if (code_ == nullptr || !code_->is_optimized()) {
return;
}
if (cached_catch_entry_moves_.IsEmpty()) {
catch_entry_moves_cache_->Insert(
pc_, CatchEntryMovesRefPtr(catch_entry_moves_));
} else {
catch_entry_moves_ = &cached_catch_entry_moves_.moves();
}
ExecuteCatchEntryMoves(*catch_entry_moves_);
}
void ExecuteCatchEntryMoves(const CatchEntryMoves& moves) {
Zone* zone = Thread::Current()->zone();
auto& value = Object::Handle(zone);
GrowableArray<Object*> dst_values;
uword fp = handler_fp;
ObjectPool* pool = nullptr;
for (int j = 0; j < moves.count(); j++) {
const CatchEntryMove& move = moves.At(j);
switch (move.source_kind()) {
case CatchEntryMove::SourceKind::kConstant:
if (pool == nullptr) {
pool = &ObjectPool::Handle(code_->GetObjectPool());
}
value = pool->ObjectAt(move.src_slot());
break;
case CatchEntryMove::SourceKind::kTaggedSlot:
value = *TaggedSlotAt(fp, move.src_slot());
break;
case CatchEntryMove::SourceKind::kDoubleSlot:
value = Double::New(*SlotAt<double>(fp, move.src_slot()));
break;
case CatchEntryMove::SourceKind::kFloat32x4Slot:
value = Float32x4::New(*SlotAt<simd128_value_t>(fp, move.src_slot()));
break;
case CatchEntryMove::SourceKind::kFloat64x2Slot:
value = Float64x2::New(*SlotAt<simd128_value_t>(fp, move.src_slot()));
break;
case CatchEntryMove::SourceKind::kInt32x4Slot:
value = Int32x4::New(*SlotAt<simd128_value_t>(fp, move.src_slot()));
break;
case CatchEntryMove::SourceKind::kInt64PairSlot:
value = Integer::New(
Utils::LowHighTo64Bits(*SlotAt<uint32_t>(fp, move.src_lo_slot()),
*SlotAt<int32_t>(fp, move.src_hi_slot())));
break;
case CatchEntryMove::SourceKind::kInt64Slot:
value = Integer::New(*SlotAt<int64_t>(fp, move.src_slot()));
break;
case CatchEntryMove::SourceKind::kInt32Slot:
value = Integer::New(*SlotAt<int32_t>(fp, move.src_slot()));
break;
case CatchEntryMove::SourceKind::kUint32Slot:
value = Integer::New(*SlotAt<uint32_t>(fp, move.src_slot()));
break;
default:
UNREACHABLE();
}
dst_values.Add(&Object::Handle(zone, value.ptr()));
}
{
NoSafepointScope no_safepoint_scope;
for (int j = 0; j < moves.count(); j++) {
const CatchEntryMove& move = moves.At(j);
*TaggedSlotAt(fp, move.dest_slot()) = dst_values[j]->ptr();
}
}
}
#if defined(DART_PRECOMPILED_RUNTIME) || defined(DART_PRECOMPILER)
void ReadCompressedCatchEntryMoves() {
const intptr_t pc_offset = pc_ - code_->PayloadStart();
const auto& td = TypedData::Handle(code_->catch_entry_moves_maps());
CatchEntryMovesMapReader reader(td);
catch_entry_moves_ = reader.ReadMovesForPcOffset(pc_offset);
}
#endif // defined(DART_PRECOMPILED_RUNTIME) || defined(DART_PRECOMPILER)
#if !defined(DART_PRECOMPILED_RUNTIME)
void GetCatchEntryMovesFromDeopt(intptr_t num_vars, StackFrame* frame) {
Isolate* isolate = thread_->isolate();
DeoptContext* deopt_context =
new DeoptContext(frame, *code_, DeoptContext::kDestIsAllocated, NULL,
NULL, true, false /* deoptimizing_code */);
isolate->set_deopt_context(deopt_context);
catch_entry_moves_ = deopt_context->ToCatchEntryMoves(num_vars);
isolate->set_deopt_context(NULL);
delete deopt_context;
}
#endif // !defined(DART_PRECOMPILED_RUNTIME)
bool needs_stacktrace;
uword handler_pc;
uword handler_sp;
uword handler_fp;
private:
template <typename T>
static T* SlotAt(uword fp, int stack_slot) {
const intptr_t frame_slot =
runtime_frame_layout.FrameSlotForVariableIndex(-stack_slot);
return reinterpret_cast<T*>(fp + frame_slot * kWordSize);
}
static ObjectPtr* TaggedSlotAt(uword fp, int stack_slot) {
return SlotAt<ObjectPtr>(fp, stack_slot);
}
typedef ReadStream::Raw<sizeof(intptr_t), intptr_t> Reader;
Thread* thread_;
Code* code_;
bool handler_pc_set_;
intptr_t pc_; // Current pc in the handler frame.
const CatchEntryMoves* catch_entry_moves_ = nullptr;
CatchEntryMovesCache* catch_entry_moves_cache_ = nullptr;
CatchEntryMovesRefPtr cached_catch_entry_moves_;
};
CatchEntryMove CatchEntryMove::ReadFrom(ReadStream* stream) {
using Reader = ReadStream::Raw<sizeof(int32_t), int32_t>;
const int32_t src = Reader::Read(stream);
const int32_t dest_and_kind = Reader::Read(stream);
return CatchEntryMove(src, dest_and_kind);
}
#if !defined(DART_PRECOMPILED_RUNTIME)
void CatchEntryMove::WriteTo(BaseWriteStream* stream) {
using Writer = BaseWriteStream::Raw<sizeof(int32_t), int32_t>;
Writer::Write(stream, src_);
Writer::Write(stream, dest_and_kind_);
}
#endif
#if !defined(PRODUCT) || defined(FORCE_INCLUDE_DISASSEMBLER)
const char* CatchEntryMove::ToCString() const {
char from[256];
switch (source_kind()) {
case SourceKind::kConstant:
Utils::SNPrint(from, ARRAY_SIZE(from), "pp[%" Pd "]", src_slot());
break;
case SourceKind::kTaggedSlot:
Utils::SNPrint(from, ARRAY_SIZE(from), "fp[%" Pd "]", src_slot());
break;
case SourceKind::kDoubleSlot:
Utils::SNPrint(from, ARRAY_SIZE(from), "f64 [fp + %" Pd "]",
src_slot() * compiler::target::kWordSize);
break;
case SourceKind::kFloat32x4Slot:
Utils::SNPrint(from, ARRAY_SIZE(from), "f32x4 [fp + %" Pd "]",
src_slot() * compiler::target::kWordSize);
break;
case SourceKind::kFloat64x2Slot:
Utils::SNPrint(from, ARRAY_SIZE(from), "f64x2 [fp + %" Pd "]",
src_slot() * compiler::target::kWordSize);
break;
case SourceKind::kInt32x4Slot:
Utils::SNPrint(from, ARRAY_SIZE(from), "i32x4 [fp + %" Pd "]",
src_slot() * compiler::target::kWordSize);
break;
case SourceKind::kInt64PairSlot:
Utils::SNPrint(from, ARRAY_SIZE(from),
"i64 ([fp + %" Pd "], [fp + %" Pd "])",
src_lo_slot() * compiler::target::kWordSize,
src_hi_slot() * compiler::target::kWordSize);
break;
case SourceKind::kInt64Slot:
Utils::SNPrint(from, ARRAY_SIZE(from), "i64 [fp + %" Pd "]",
src_slot() * compiler::target::kWordSize);
break;
case SourceKind::kInt32Slot:
Utils::SNPrint(from, ARRAY_SIZE(from), "i32 [fp + %" Pd "]",
src_slot() * compiler::target::kWordSize);
break;
case SourceKind::kUint32Slot:
Utils::SNPrint(from, ARRAY_SIZE(from), "u32 [fp + %" Pd "]",
src_slot() * compiler::target::kWordSize);
break;
default:
UNREACHABLE();
}
return Thread::Current()->zone()->PrintToString("fp[%" Pd "] <- %s",
dest_slot(), from);
}
void CatchEntryMovesMapReader::PrintEntries() {
NoSafepointScope no_safepoint;
using Reader = ReadStream::Raw<sizeof(intptr_t), intptr_t>;
ReadStream stream(static_cast<uint8_t*>(bytes_.DataAddr(0)), bytes_.Length());
while (stream.PendingBytes() > 0) {
const intptr_t stream_position = stream.Position();
const intptr_t target_pc_offset = Reader::Read(&stream);
const intptr_t prefix_length = Reader::Read(&stream);
const intptr_t suffix_length = Reader::Read(&stream);
const intptr_t length = prefix_length + suffix_length;
Reader::Read(&stream); // Skip suffix_offset
for (intptr_t j = 0; j < prefix_length; j++) {
CatchEntryMove::ReadFrom(&stream);
}
ReadStream inner_stream(static_cast<uint8_t*>(bytes_.DataAddr(0)),
bytes_.Length());
CatchEntryMoves* moves = ReadCompressedCatchEntryMovesSuffix(
&inner_stream, stream_position, length);
THR_Print(" [code+0x%08" Px "]: (% " Pd " moves)\n", target_pc_offset,
moves->count());
for (intptr_t i = 0; i < moves->count(); i++) {
THR_Print(" %s\n", moves->At(i).ToCString());
}
CatchEntryMoves::Free(moves);
}
}
#endif // !defined(PRODUCT) || defined(FORCE_INCLUDE_DISASSEMBLER)
CatchEntryMoves* CatchEntryMovesMapReader::ReadMovesForPcOffset(
intptr_t pc_offset) {
NoSafepointScope no_safepoint;
ReadStream stream(static_cast<uint8_t*>(bytes_.DataAddr(0)), bytes_.Length());
intptr_t position = 0;
intptr_t length = 0;
FindEntryForPc(&stream, pc_offset, &position, &length);
return ReadCompressedCatchEntryMovesSuffix(&stream, position, length);
}
void CatchEntryMovesMapReader::FindEntryForPc(ReadStream* stream,
intptr_t pc_offset,
intptr_t* position,
intptr_t* length) {
using Reader = ReadStream::Raw<sizeof(intptr_t), intptr_t>;
while (stream->PendingBytes() > 0) {
const intptr_t stream_position = stream->Position();
const intptr_t target_pc_offset = Reader::Read(stream);
const intptr_t prefix_length = Reader::Read(stream);
const intptr_t suffix_length = Reader::Read(stream);
Reader::Read(stream); // Skip suffix_offset
if (pc_offset == target_pc_offset) {
*position = stream_position;
*length = prefix_length + suffix_length;
return;
}
// Skip the prefix moves.
for (intptr_t j = 0; j < prefix_length; j++) {
CatchEntryMove::ReadFrom(stream);
}
}
UNREACHABLE();
}
CatchEntryMoves* CatchEntryMovesMapReader::ReadCompressedCatchEntryMovesSuffix(
ReadStream* stream,
intptr_t offset,
intptr_t length) {
using Reader = ReadStream::Raw<sizeof(intptr_t), intptr_t>;
CatchEntryMoves* moves = CatchEntryMoves::Allocate(length);
intptr_t remaining_length = length;
intptr_t moves_offset = 0;
while (remaining_length > 0) {
stream->SetPosition(offset);
Reader::Read(stream); // skip pc_offset
Reader::Read(stream); // skip prefix length
const intptr_t suffix_length = Reader::Read(stream);
const intptr_t suffix_offset = Reader::Read(stream);
const intptr_t to_read = remaining_length - suffix_length;
if (to_read > 0) {
for (int j = 0; j < to_read; j++) {
// The prefix is written from the back.
moves->At(moves_offset + to_read - j - 1) =
CatchEntryMove::ReadFrom(stream);
}
remaining_length -= to_read;
moves_offset += to_read;
}
offset = suffix_offset;
}
return moves;
}
static void FindErrorHandler(uword* handler_pc,
uword* handler_sp,
uword* handler_fp) {
StackFrameIterator frames(ValidationPolicy::kDontValidateFrames,
Thread::Current(),
StackFrameIterator::kNoCrossThreadIteration);
StackFrame* frame = frames.NextFrame();
ASSERT(frame != NULL);
while (!frame->IsEntryFrame()) {
frame = frames.NextFrame();
ASSERT(frame != NULL);
}
ASSERT(frame->IsEntryFrame());
*handler_pc = frame->pc();
*handler_sp = frame->sp();
*handler_fp = frame->fp();
}
static void ClearLazyDeopts(Thread* thread, uword frame_pointer) {
if (thread->pending_deopts().HasPendingDeopts()) {
// We may be jumping over frames scheduled for lazy deopt. Remove these
// frames from the pending deopt table, but only after unmarking them so
// any stack walk that happens before the stack is unwound will still work.
{
DartFrameIterator frames(thread,
StackFrameIterator::kNoCrossThreadIteration);
for (StackFrame* frame = frames.NextFrame(); frame != nullptr;
frame = frames.NextFrame()) {
if (frame->fp() >= frame_pointer) {
break;
}
if (frame->IsMarkedForLazyDeopt()) {
frame->UnmarkForLazyDeopt();
}
}
}
#if defined(DEBUG)
ValidateFrames();
#endif
thread->pending_deopts().ClearPendingDeoptsBelow(
frame_pointer, PendingDeopts::kClearDueToThrow);
#if defined(DEBUG)
ValidateFrames();
#endif
}
}
static void JumpToExceptionHandler(Thread* thread,
uword program_counter,
uword stack_pointer,
uword frame_pointer,
const Object& exception_object,
const Object& stacktrace_object) {
uword remapped_pc = thread->pending_deopts().RemapExceptionPCForDeopt(
program_counter, frame_pointer);
thread->set_active_exception(exception_object);
thread->set_active_stacktrace(stacktrace_object);
thread->set_resume_pc(remapped_pc);
uword run_exception_pc = StubCode::RunExceptionHandler().EntryPoint();
Exceptions::JumpToFrame(thread, run_exception_pc, stack_pointer,
frame_pointer, false /* do not clear deopt */);
}
NO_SANITIZE_SAFE_STACK // This function manipulates the safestack pointer.
void Exceptions::JumpToFrame(Thread* thread,
uword program_counter,
uword stack_pointer,
uword frame_pointer,
bool clear_deopt_at_target) {
const uword fp_for_clearing =
(clear_deopt_at_target ? frame_pointer + 1 : frame_pointer);
ClearLazyDeopts(thread, fp_for_clearing);
#if defined(USING_SIMULATOR)
// Unwinding of the C++ frames and destroying of their stack resources is done
// by the simulator, because the target stack_pointer is a simulated stack
// pointer and not the C++ stack pointer.
// Continue simulating at the given pc in the given frame after setting up the
// exception object in the kExceptionObjectReg register and the stacktrace
// object (may be raw null) in the kStackTraceObjectReg register.
Simulator::Current()->JumpToFrame(program_counter, stack_pointer,
frame_pointer, thread);
#else
// Prepare for unwinding frames by destroying all the stack resources
// in the previous frames.
StackResource::Unwind(thread);
// Call a stub to set up the exception object in kExceptionObjectReg,
// to set up the stacktrace object in kStackTraceObjectReg, and to
// continue execution at the given pc in the given frame.
typedef void (*ExcpHandler)(uword, uword, uword, Thread*);
ExcpHandler func =
reinterpret_cast<ExcpHandler>(StubCode::JumpToFrame().EntryPoint());
// Unpoison the stack before we tear it down in the generated stub code.
uword current_sp = OSThread::GetCurrentStackPointer() - 1024;
ASAN_UNPOISON(reinterpret_cast<void*>(current_sp),
stack_pointer - current_sp);
// We are jumping over C++ frames, so we have to set the safestack pointer
// back to what it was when we entered the runtime from Dart code.
#if defined(USING_SAFE_STACK)
const uword saved_ssp = thread->saved_safestack_limit();
OSThread::SetCurrentSafestackPointer(saved_ssp);
#endif
#if defined(USING_SHADOW_CALL_STACK)
// The shadow call stack register will be restored by the JumpToFrame stub.
#endif
func(program_counter, stack_pointer, frame_pointer, thread);
#endif
UNREACHABLE();
}
static FieldPtr LookupStackTraceField(const Instance& instance) {
if (instance.GetClassId() < kNumPredefinedCids) {
// 'class Error' is not a predefined class.
return Field::null();
}
Thread* thread = Thread::Current();
Zone* zone = thread->zone();
auto isolate_group = thread->isolate_group();
const auto& error_class =
Class::Handle(zone, isolate_group->object_store()->error_class());
// If instance class extends 'class Error' return '_stackTrace' field.
Class& test_class = Class::Handle(zone, instance.clazz());
AbstractType& type = AbstractType::Handle(zone, AbstractType::null());
while (true) {
if (test_class.ptr() == error_class.ptr()) {
return error_class.LookupInstanceFieldAllowPrivate(
Symbols::_stackTrace());
}
type = test_class.super_type();
if (type.IsNull()) return Field::null();
test_class = type.type_class();
}
UNREACHABLE();
return Field::null();
}
StackTracePtr Exceptions::CurrentStackTrace() {
return GetStackTraceForException();
}
DART_NORETURN
static void ThrowExceptionHelper(Thread* thread,
const Instance& incoming_exception,
const Instance& existing_stacktrace,
const bool is_rethrow) {
// SuspendLongJumpScope during Dart entry ensures that if a longjmp base is
// available, it is the innermost error handler. If one is available, so
// should jump there instead.
RELEASE_ASSERT(thread->long_jump_base() == nullptr);
Zone* zone = thread->zone();
auto object_store = thread->isolate_group()->object_store();
Isolate* isolate = thread->isolate();
#if !defined(PRODUCT)
// Do not notify debugger on stack overflow and out of memory exceptions.
// The VM would crash when the debugger calls back into the VM to
// get values of variables.
if (incoming_exception.ptr() != object_store->out_of_memory() &&
incoming_exception.ptr() != object_store->stack_overflow()) {
isolate->debugger()->PauseException(incoming_exception);
}
#endif
bool use_preallocated_stacktrace = false;
Instance& exception = Instance::Handle(zone, incoming_exception.ptr());
if (exception.IsNull()) {
exception ^=
Exceptions::Create(Exceptions::kNullThrown, Object::empty_array());
} else if (exception.ptr() == object_store->out_of_memory() ||
exception.ptr() == object_store->stack_overflow()) {
use_preallocated_stacktrace = true;
}
// Find the exception handler and determine if the handler needs a
// stacktrace.
ExceptionHandlerFinder finder(thread);
bool handler_exists = finder.Find();
uword handler_pc = finder.handler_pc;
uword handler_sp = finder.handler_sp;
uword handler_fp = finder.handler_fp;
bool handler_needs_stacktrace = finder.needs_stacktrace;
Instance& stacktrace = Instance::Handle(zone);
if (use_preallocated_stacktrace) {
if (handler_pc == 0) {
// No Dart frame.
ASSERT(incoming_exception.ptr() == object_store->out_of_memory());
const UnhandledException& error = UnhandledException::Handle(
zone,
isolate->isolate_object_store()->preallocated_unhandled_exception());
thread->long_jump_base()->Jump(1, error);
UNREACHABLE();
}
stacktrace = isolate->isolate_object_store()->preallocated_stack_trace();
PreallocatedStackTraceBuilder frame_builder(stacktrace);
ASSERT(existing_stacktrace.IsNull() ||
(existing_stacktrace.ptr() == stacktrace.ptr()));
ASSERT(existing_stacktrace.IsNull() || is_rethrow);
if (handler_needs_stacktrace && existing_stacktrace.IsNull()) {
BuildStackTrace(&frame_builder);
}
} else {
if (!existing_stacktrace.IsNull()) {
// If we have an existing stack trace then this better be a rethrow. The
// reverse is not necessarily true (e.g. Dart_PropagateError can cause
// a rethrow being called without an existing stacktrace.)
ASSERT(is_rethrow);
stacktrace = existing_stacktrace.ptr();
} else {
// Get stacktrace field of class Error to determine whether we have a
// subclass of Error which carries around its stack trace.
const Field& stacktrace_field =
Field::Handle(zone, LookupStackTraceField(exception));
if (!stacktrace_field.IsNull() || handler_needs_stacktrace) {
// Collect the stacktrace if needed.
ASSERT(existing_stacktrace.IsNull());
stacktrace = Exceptions::CurrentStackTrace();
// If we have an Error object, then set its stackTrace field only if it
// not yet initialized.
if (!stacktrace_field.IsNull() &&
(exception.GetField(stacktrace_field) == Object::null())) {
exception.SetField(stacktrace_field, stacktrace);
}
}
}
}
// We expect to find a handler_pc, if the exception is unhandled
// then we expect to at least have the dart entry frame on the
// stack as Exceptions::Throw should happen only after a dart
// invocation has been done.
ASSERT(handler_pc != 0);
if (FLAG_print_stacktrace_at_throw) {
THR_Print("Exception '%s' thrown:\n", exception.ToCString());
THR_Print("%s\n", stacktrace.ToCString());
}
if (handler_exists) {
finder.PrepareFrameForCatchEntry();
// Found a dart handler for the exception, jump to it.
JumpToExceptionHandler(thread, handler_pc, handler_sp, handler_fp,
exception, stacktrace);
} else {
// No dart exception handler found in this invocation sequence,
// so we create an unhandled exception object and return to the
// invocation stub so that it returns this unhandled exception
// object. The C++ code which invoked this dart sequence can check
// and do the appropriate thing (rethrow the exception to the
// dart invocation sequence above it, print diagnostics and terminate
// the isolate etc.). This can happen in the compiler, which is not
// allowed to allocate in new space, so we pass the kOld argument.
const UnhandledException& unhandled_exception = UnhandledException::Handle(
zone, exception.ptr() == object_store->out_of_memory()
? isolate->isolate_object_store()
->preallocated_unhandled_exception()
: UnhandledException::New(exception, stacktrace, Heap::kOld));
stacktrace = StackTrace::null();
JumpToExceptionHandler(thread, handler_pc, handler_sp, handler_fp,
unhandled_exception, stacktrace);
}
UNREACHABLE();
}
// Static helpers for allocating, initializing, and throwing an error instance.
// Return the script of the Dart function that called the native entry or the
// runtime entry. The frame iterator points to the callee.
ScriptPtr Exceptions::GetCallerScript(DartFrameIterator* iterator) {
StackFrame* caller_frame = iterator->NextFrame();
ASSERT(caller_frame != NULL && caller_frame->IsDartFrame());
const Function& caller = Function::Handle(caller_frame->LookupDartFunction());
#if defined(DART_PRECOMPILED_RUNTIME)
if (caller.IsNull()) return Script::null();
#else
ASSERT(!caller.IsNull());
#endif
return caller.script();
}
// Allocate a new instance of the given class name.
// TODO(hausner): Rename this NewCoreInstance to call out the fact that
// the class name is resolved in the core library implicitly?
InstancePtr Exceptions::NewInstance(const char* class_name) {
Thread* thread = Thread::Current();
Zone* zone = thread->zone();
const String& cls_name =
String::Handle(zone, Symbols::New(thread, class_name));
const Library& core_lib = Library::Handle(Library::CoreLibrary());
// No ambiguity error expected: passing NULL.
Class& cls = Class::Handle(core_lib.LookupClass(cls_name));
ASSERT(!cls.IsNull());
// There are no parameterized error types, so no need to set type arguments.
return Instance::New(cls);
}
// Allocate, initialize, and throw a TypeError or CastError.
// If error_msg is not null, throw a TypeError, even for a type cast.
void Exceptions::CreateAndThrowTypeError(TokenPosition location,
const AbstractType& src_type,
const AbstractType& dst_type,
const String& dst_name) {
ASSERT(!dst_name.IsNull()); // Pass Symbols::Empty() instead.
Thread* thread = Thread::Current();
Zone* zone = thread->zone();
const Array& args = Array::Handle(zone, Array::New(4));
ExceptionType exception_type =
(dst_name.ptr() == Symbols::InTypeCast().ptr()) ? kCast : kType;
DartFrameIterator iterator(thread,
StackFrameIterator::kNoCrossThreadIteration);
const Script& script = Script::Handle(zone, GetCallerScript(&iterator));
const String& url = String::Handle(
zone, script.IsNull() ? Symbols::OptimizedOut().ptr() : script.url());
intptr_t line = -1;
intptr_t column = -1;
if (!script.IsNull()) {
script.GetTokenLocation(location, &line, &column);
}
// Initialize '_url', '_line', and '_column' arguments.
args.SetAt(0, url);
args.SetAt(1, Smi::Handle(zone, Smi::New(line)));
args.SetAt(2, Smi::Handle(zone, Smi::New(column)));
// Construct '_errorMsg'.
const GrowableObjectArray& pieces =
GrowableObjectArray::Handle(zone, GrowableObjectArray::New(20));
if (!dst_type.IsNull()) {
// Describe the type error.
if (!src_type.IsNull()) {
pieces.Add(Symbols::TypeQuote());
pieces.Add(String::Handle(zone, src_type.UserVisibleName()));
pieces.Add(Symbols::QuoteIsNotASubtypeOf());
}
pieces.Add(Symbols::TypeQuote());
pieces.Add(String::Handle(zone, dst_type.UserVisibleName()));
pieces.Add(Symbols::SingleQuote());
if (exception_type == kCast) {
pieces.Add(dst_name);
} else if (dst_name.Length() > 0) {
pieces.Add(Symbols::SpaceOfSpace());
pieces.Add(Symbols::SingleQuote());
pieces.Add(dst_name);
pieces.Add(Symbols::SingleQuote());
}
// Print ambiguous URIs of src and dst types.
URIs uris(zone, 12);
if (!src_type.IsNull()) {
src_type.EnumerateURIs(&uris);
}
if (!dst_type.IsDynamicType() && !dst_type.IsVoidType() &&
!dst_type.IsNeverType()) {
dst_type.EnumerateURIs(&uris);
}
const String& formatted_uris =
String::Handle(zone, AbstractType::PrintURIs(&uris));
if (formatted_uris.Length() > 0) {
pieces.Add(Symbols::SpaceWhereNewLine());
pieces.Add(formatted_uris);
}
}
const Array& arr = Array::Handle(zone, Array::MakeFixedLength(pieces));
const String& error_msg = String::Handle(zone, String::ConcatAll(arr));
args.SetAt(3, error_msg);
// Type errors in the core library may be difficult to diagnose.
// Print type error information before throwing the error when debugging.
if (FLAG_print_stacktrace_at_throw) {
THR_Print("'%s': Failed type check: line %" Pd " pos %" Pd ": ",
String::Handle(zone, script.url()).ToCString(), line, column);
THR_Print("%s\n", error_msg.ToCString());
}
// Throw TypeError or CastError instance.
Exceptions::ThrowByType(exception_type, args);
UNREACHABLE();
}
void Exceptions::Throw(Thread* thread, const Instance& exception) {
// Null object is a valid exception object.
ThrowExceptionHelper(thread, exception, StackTrace::Handle(thread->zone()),
false);
}
void Exceptions::ReThrow(Thread* thread,
const Instance& exception,
const Instance& stacktrace) {
// Null object is a valid exception object.
ThrowExceptionHelper(thread, exception, stacktrace, true);
}
void Exceptions::PropagateError(const Error& error) {
ASSERT(!error.IsNull());
Thread* thread = Thread::Current();
// SuspendLongJumpScope during Dart entry ensures that if a longjmp base is
// available, it is the innermost error handler. If one is available, so
// should jump there instead.
RELEASE_ASSERT(thread->long_jump_base() == nullptr);
Zone* zone = thread->zone();
if (error.IsUnhandledException()) {
// If the error object represents an unhandled exception, then
// rethrow the exception in the normal fashion.
const UnhandledException& uhe = UnhandledException::Cast(error);
const Instance& exc = Instance::Handle(zone, uhe.exception());
const Instance& stk = Instance::Handle(zone, uhe.stacktrace());
Exceptions::ReThrow(thread, exc, stk);
} else {
// Return to the invocation stub and return this error object. The
// C++ code which invoked this dart sequence can check and do the
// appropriate thing.
uword handler_pc = 0;
uword handler_sp = 0;
uword handler_fp = 0;
FindErrorHandler(&handler_pc, &handler_sp, &handler_fp);
JumpToExceptionHandler(thread, handler_pc, handler_sp, handler_fp, error,
StackTrace::Handle(zone)); // Null stacktrace.
}
UNREACHABLE();
}
void Exceptions::PropagateToEntry(const Error& error) {
Thread* thread = Thread::Current();
Zone* zone = thread->zone();
ASSERT(thread->top_exit_frame_info() != 0);
Instance& stacktrace = Instance::Handle(zone);
if (error.IsUnhandledException()) {
const UnhandledException& uhe = UnhandledException::Cast(error);
stacktrace = uhe.stacktrace();
} else {
stacktrace = Exceptions::CurrentStackTrace();
}
uword handler_pc = 0;
uword handler_sp = 0;
uword handler_fp = 0;
FindErrorHandler(&handler_pc, &handler_sp, &handler_fp);
JumpToExceptionHandler(thread, handler_pc, handler_sp, handler_fp, error,
stacktrace);
UNREACHABLE();
}
void Exceptions::ThrowByType(ExceptionType type, const Array& arguments) {
Thread* thread = Thread::Current();
const Object& result =
Object::Handle(thread->zone(), Create(type, arguments));
if (result.IsError()) {
// We got an error while constructing the exception object.
// Propagate the error instead of throwing the exception.
PropagateError(Error::Cast(result));
} else {
ASSERT(result.IsInstance());
Throw(thread, Instance::Cast(result));
}
}
void Exceptions::ThrowOOM() {
auto thread = Thread::Current();
auto isolate_group = thread->isolate_group();
const Instance& oom = Instance::Handle(
thread->zone(), isolate_group->object_store()->out_of_memory());
Throw(thread, oom);
}
void Exceptions::ThrowStackOverflow() {
auto thread = Thread::Current();
auto isolate_group = thread->isolate_group();
const Instance& stack_overflow = Instance::Handle(
thread->zone(), isolate_group->object_store()->stack_overflow());
Throw(thread, stack_overflow);
}
void Exceptions::ThrowArgumentError(const Instance& arg) {
const Array& args = Array::Handle(Array::New(1));
args.SetAt(0, arg);
Exceptions::ThrowByType(Exceptions::kArgument, args);
}
void Exceptions::ThrowRangeError(const char* argument_name,
const Integer& argument_value,
intptr_t expected_from,
intptr_t expected_to) {
const Array& args = Array::Handle(Array::New(4));
args.SetAt(0, argument_value);
args.SetAt(1, Integer::Handle(Integer::New(expected_from)));
args.SetAt(2, Integer::Handle(Integer::New(expected_to)));
args.SetAt(3, String::Handle(String::New(argument_name)));
Exceptions::ThrowByType(Exceptions::kRange, args);
}
void Exceptions::ThrowUnsupportedError(const char* msg) {
const Array& args = Array::Handle(Array::New(1));
args.SetAt(0, String::Handle(String::New(msg)));
Exceptions::ThrowByType(Exceptions::kUnsupported, args);
}
void Exceptions::ThrowCompileTimeError(const LanguageError& error) {
const Array& args = Array::Handle(Array::New(1));
args.SetAt(0, String::Handle(error.FormatMessage()));
Exceptions::ThrowByType(Exceptions::kCompileTimeError, args);
}
void Exceptions::ThrowLateFieldNotInitialized(const String& name) {
const Array& args = Array::Handle(Array::New(1));
args.SetAt(0, name);
Exceptions::ThrowByType(Exceptions::kLateFieldNotInitialized, args);
}
void Exceptions::ThrowLateFieldAssignedDuringInitialization(
const String& name) {
const Array& args = Array::Handle(Array::New(1));
args.SetAt(0, name);
Exceptions::ThrowByType(Exceptions::kLateFieldAssignedDuringInitialization,
args);
}
ObjectPtr Exceptions::Create(ExceptionType type, const Array& arguments) {
Library& library = Library::Handle();
const String* class_name = NULL;
const String* constructor_name = &Symbols::Dot();
switch (type) {
case kNone:
case kStackOverflow:
case kOutOfMemory:
UNREACHABLE();
break;
case kRange:
library = Library::CoreLibrary();
class_name = &Symbols::RangeError();
constructor_name = &Symbols::DotRange();
break;
case kRangeMsg:
library = Library::CoreLibrary();
class_name = &Symbols::RangeError();
constructor_name = &Symbols::Dot();
break;
case kArgument:
library = Library::CoreLibrary();
class_name = &Symbols::ArgumentError();
break;
case kArgumentValue:
library = Library::CoreLibrary();
class_name = &Symbols::ArgumentError();
constructor_name = &Symbols::DotValue();
break;
case kIntegerDivisionByZeroException:
library = Library::CoreLibrary();
class_name = &Symbols::IntegerDivisionByZeroException();
break;
case kNoSuchMethod:
library = Library::CoreLibrary();
class_name = &Symbols::NoSuchMethodError();
constructor_name = &Symbols::DotWithType();
break;
case kFormat:
library = Library::CoreLibrary();
class_name = &Symbols::FormatException();
break;
case kUnsupported:
library = Library::CoreLibrary();
class_name = &Symbols::UnsupportedError();
break;
case kNullThrown:
library = Library::CoreLibrary();
class_name = &Symbols::NullThrownError();
break;
case kIsolateSpawn:
library = Library::IsolateLibrary();
class_name = &Symbols::IsolateSpawnException();
break;
case kAssertion:
library = Library::CoreLibrary();
class_name = &Symbols::AssertionError();
constructor_name = &Symbols::DotCreate();
break;
case kCast:
library = Library::CoreLibrary();
class_name = &Symbols::CastError();
constructor_name = &Symbols::DotCreate();
break;
case kType:
library = Library::CoreLibrary();
class_name = &Symbols::TypeError();
constructor_name = &Symbols::DotCreate();
break;
case kFallThrough:
library = Library::CoreLibrary();
class_name = &Symbols::FallThroughError();
constructor_name = &Symbols::DotCreate();
break;
case kAbstractClassInstantiation:
library = Library::CoreLibrary();
class_name = &Symbols::AbstractClassInstantiationError();
constructor_name = &Symbols::DotCreate();
break;
case kCyclicInitializationError:
library = Library::CoreLibrary();
class_name = &Symbols::CyclicInitializationError();
break;
case kCompileTimeError:
library = Library::CoreLibrary();
class_name = &Symbols::_CompileTimeError();
break;
case kLateFieldAssignedDuringInitialization:
library = Library::InternalLibrary();
class_name = &Symbols::LateError();
constructor_name = &Symbols::DotFieldADI();
break;
case kLateFieldNotInitialized:
library = Library::InternalLibrary();
class_name = &Symbols::LateError();
constructor_name = &Symbols::DotFieldNI();
break;
}
Thread* thread = Thread::Current();
NoReloadScope no_reload_scope(thread);
return DartLibraryCalls::InstanceCreate(library, *class_name,
*constructor_name, arguments);
}
UnhandledExceptionPtr Exceptions::CreateUnhandledException(Zone* zone,
ExceptionType type,
const char* msg) {
const String& error_str = String::Handle(zone, String::New(msg));
const Array& args = Array::Handle(zone, Array::New(1));
args.SetAt(0, error_str);
Object& result = Object::Handle(zone, Exceptions::Create(type, args));
const StackTrace& stacktrace = StackTrace::Handle(zone);
return UnhandledException::New(Instance::Cast(result), stacktrace);
}
} // namespace dart