// Copyright 2012 the V8 project authors. All rights reserved. // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions are // met: // // * Redistributions of source code must retain the above copyright // notice, this list of conditions and the following disclaimer. // * Redistributions in binary form must reproduce the above // copyright notice, this list of conditions and the following // disclaimer in the documentation and/or other materials provided // with the distribution. // * Neither the name of Google Inc. nor the names of its // contributors may be used to endorse or promote products derived // from this software without specific prior written permission. // // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. #include "v8.h" #include "ast.h" #include "deoptimizer.h" #include "frames-inl.h" #include "full-codegen.h" #include "lazy-instance.h" #include "mark-compact.h" #include "safepoint-table.h" #include "scopeinfo.h" #include "string-stream.h" #include "allocation-inl.h" namespace v8 { namespace internal { static ReturnAddressLocationResolver return_address_location_resolver = NULL; // Resolves pc_address through the resolution address function if one is set. static inline Address* ResolveReturnAddressLocation(Address* pc_address) { if (return_address_location_resolver == NULL) { return pc_address; } else { return reinterpret_cast( return_address_location_resolver( reinterpret_cast(pc_address))); } } // Iterator that supports traversing the stack handlers of a // particular frame. Needs to know the top of the handler chain. class StackHandlerIterator BASE_EMBEDDED { public: StackHandlerIterator(const StackFrame* frame, StackHandler* handler) : limit_(frame->fp()), handler_(handler) { // Make sure the handler has already been unwound to this frame. ASSERT(frame->sp() <= handler->address()); } StackHandler* handler() const { return handler_; } bool done() { return handler_ == NULL || handler_->address() > limit_; } void Advance() { ASSERT(!done()); handler_ = handler_->next(); } private: const Address limit_; StackHandler* handler_; }; // ------------------------------------------------------------------------- #define INITIALIZE_SINGLETON(type, field) field##_(this), StackFrameIterator::StackFrameIterator() : isolate_(Isolate::Current()), STACK_FRAME_TYPE_LIST(INITIALIZE_SINGLETON) frame_(NULL), handler_(NULL), thread_(isolate_->thread_local_top()), fp_(NULL), sp_(NULL), advance_(&StackFrameIterator::AdvanceWithHandler) { Reset(); } StackFrameIterator::StackFrameIterator(Isolate* isolate) : isolate_(isolate), STACK_FRAME_TYPE_LIST(INITIALIZE_SINGLETON) frame_(NULL), handler_(NULL), thread_(isolate_->thread_local_top()), fp_(NULL), sp_(NULL), advance_(&StackFrameIterator::AdvanceWithHandler) { Reset(); } StackFrameIterator::StackFrameIterator(Isolate* isolate, ThreadLocalTop* t) : isolate_(isolate), STACK_FRAME_TYPE_LIST(INITIALIZE_SINGLETON) frame_(NULL), handler_(NULL), thread_(t), fp_(NULL), sp_(NULL), advance_(&StackFrameIterator::AdvanceWithHandler) { Reset(); } StackFrameIterator::StackFrameIterator(Isolate* isolate, bool use_top, Address fp, Address sp) : isolate_(isolate), STACK_FRAME_TYPE_LIST(INITIALIZE_SINGLETON) frame_(NULL), handler_(NULL), thread_(use_top ? isolate_->thread_local_top() : NULL), fp_(use_top ? NULL : fp), sp_(sp), advance_(use_top ? &StackFrameIterator::AdvanceWithHandler : &StackFrameIterator::AdvanceWithoutHandler) { if (use_top || fp != NULL) { Reset(); } } #undef INITIALIZE_SINGLETON void StackFrameIterator::AdvanceWithHandler() { ASSERT(!done()); // Compute the state of the calling frame before restoring // callee-saved registers and unwinding handlers. This allows the // frame code that computes the caller state to access the top // handler and the value of any callee-saved register if needed. StackFrame::State state; StackFrame::Type type = frame_->GetCallerState(&state); // Unwind handlers corresponding to the current frame. StackHandlerIterator it(frame_, handler_); while (!it.done()) it.Advance(); handler_ = it.handler(); // Advance to the calling frame. frame_ = SingletonFor(type, &state); // When we're done iterating over the stack frames, the handler // chain must have been completely unwound. ASSERT(!done() || handler_ == NULL); } void StackFrameIterator::AdvanceWithoutHandler() { // A simpler version of Advance which doesn't care about handler. ASSERT(!done()); StackFrame::State state; StackFrame::Type type = frame_->GetCallerState(&state); frame_ = SingletonFor(type, &state); } void StackFrameIterator::Reset() { StackFrame::State state; StackFrame::Type type; if (thread_ != NULL) { type = ExitFrame::GetStateForFramePointer( Isolate::c_entry_fp(thread_), &state); handler_ = StackHandler::FromAddress( Isolate::handler(thread_)); } else { ASSERT(fp_ != NULL); state.fp = fp_; state.sp = sp_; state.pc_address = ResolveReturnAddressLocation( reinterpret_cast(StandardFrame::ComputePCAddress(fp_))); type = StackFrame::ComputeType(isolate(), &state); } if (SingletonFor(type) == NULL) return; frame_ = SingletonFor(type, &state); } StackFrame* StackFrameIterator::SingletonFor(StackFrame::Type type, StackFrame::State* state) { if (type == StackFrame::NONE) return NULL; StackFrame* result = SingletonFor(type); ASSERT(result != NULL); result->state_ = *state; return result; } StackFrame* StackFrameIterator::SingletonFor(StackFrame::Type type) { #define FRAME_TYPE_CASE(type, field) \ case StackFrame::type: result = &field##_; break; StackFrame* result = NULL; switch (type) { case StackFrame::NONE: return NULL; STACK_FRAME_TYPE_LIST(FRAME_TYPE_CASE) default: break; } return result; #undef FRAME_TYPE_CASE } // ------------------------------------------------------------------------- StackTraceFrameIterator::StackTraceFrameIterator() { if (!done() && !IsValidFrame()) Advance(); } StackTraceFrameIterator::StackTraceFrameIterator(Isolate* isolate) : JavaScriptFrameIterator(isolate) { if (!done() && !IsValidFrame()) Advance(); } void StackTraceFrameIterator::Advance() { while (true) { JavaScriptFrameIterator::Advance(); if (done()) return; if (IsValidFrame()) return; } } bool StackTraceFrameIterator::IsValidFrame() { if (!frame()->function()->IsJSFunction()) return false; Object* script = JSFunction::cast(frame()->function())->shared()->script(); // Don't show functions from native scripts to user. return (script->IsScript() && Script::TYPE_NATIVE != Script::cast(script)->type()->value()); } // ------------------------------------------------------------------------- bool SafeStackFrameIterator::ExitFrameValidator::IsValidFP(Address fp) { if (!validator_.IsValid(fp)) return false; Address sp = ExitFrame::ComputeStackPointer(fp); if (!validator_.IsValid(sp)) return false; StackFrame::State state; ExitFrame::FillState(fp, sp, &state); if (!validator_.IsValid(reinterpret_cast
(state.pc_address))) { return false; } return *state.pc_address != NULL; } SafeStackFrameIterator::ActiveCountMaintainer::ActiveCountMaintainer( Isolate* isolate) : isolate_(isolate) { isolate_->set_safe_stack_iterator_counter( isolate_->safe_stack_iterator_counter() + 1); } SafeStackFrameIterator::ActiveCountMaintainer::~ActiveCountMaintainer() { isolate_->set_safe_stack_iterator_counter( isolate_->safe_stack_iterator_counter() - 1); } SafeStackFrameIterator::SafeStackFrameIterator( Isolate* isolate, Address fp, Address sp, Address low_bound, Address high_bound) : maintainer_(isolate), stack_validator_(low_bound, high_bound), is_valid_top_(IsValidTop(isolate, low_bound, high_bound)), is_valid_fp_(IsWithinBounds(low_bound, high_bound, fp)), is_working_iterator_(is_valid_top_ || is_valid_fp_), iteration_done_(!is_working_iterator_), iterator_(isolate, is_valid_top_, is_valid_fp_ ? fp : NULL, sp) { } bool SafeStackFrameIterator::is_active(Isolate* isolate) { return isolate->safe_stack_iterator_counter() > 0; } bool SafeStackFrameIterator::IsValidTop(Isolate* isolate, Address low_bound, Address high_bound) { ThreadLocalTop* top = isolate->thread_local_top(); Address fp = Isolate::c_entry_fp(top); ExitFrameValidator validator(low_bound, high_bound); if (!validator.IsValidFP(fp)) return false; return Isolate::handler(top) != NULL; } void SafeStackFrameIterator::Advance() { ASSERT(is_working_iterator_); ASSERT(!done()); StackFrame* last_frame = iterator_.frame(); Address last_sp = last_frame->sp(), last_fp = last_frame->fp(); // Before advancing to the next stack frame, perform pointer validity tests iteration_done_ = !IsValidFrame(last_frame) || !CanIterateHandles(last_frame, iterator_.handler()) || !IsValidCaller(last_frame); if (iteration_done_) return; iterator_.Advance(); if (iterator_.done()) return; // Check that we have actually moved to the previous frame in the stack StackFrame* prev_frame = iterator_.frame(); iteration_done_ = prev_frame->sp() < last_sp || prev_frame->fp() < last_fp; } bool SafeStackFrameIterator::CanIterateHandles(StackFrame* frame, StackHandler* handler) { // If StackIterator iterates over StackHandles, verify that // StackHandlerIterator can be instantiated (see StackHandlerIterator // constructor.) return !is_valid_top_ || (frame->sp() <= handler->address()); } bool SafeStackFrameIterator::IsValidFrame(StackFrame* frame) const { return IsValidStackAddress(frame->sp()) && IsValidStackAddress(frame->fp()); } bool SafeStackFrameIterator::IsValidCaller(StackFrame* frame) { StackFrame::State state; if (frame->is_entry() || frame->is_entry_construct()) { // See EntryFrame::GetCallerState. It computes the caller FP address // and calls ExitFrame::GetStateForFramePointer on it. We need to be // sure that caller FP address is valid. Address caller_fp = Memory::Address_at( frame->fp() + EntryFrameConstants::kCallerFPOffset); ExitFrameValidator validator(stack_validator_); if (!validator.IsValidFP(caller_fp)) return false; } else if (frame->is_arguments_adaptor()) { // See ArgumentsAdaptorFrame::GetCallerStackPointer. It assumes that // the number of arguments is stored on stack as Smi. We need to check // that it really an Smi. Object* number_of_args = reinterpret_cast(frame)-> GetExpression(0); if (!number_of_args->IsSmi()) { return false; } } frame->ComputeCallerState(&state); return IsValidStackAddress(state.sp) && IsValidStackAddress(state.fp) && iterator_.SingletonFor(frame->GetCallerState(&state)) != NULL; } void SafeStackFrameIterator::Reset() { if (is_working_iterator_) { iterator_.Reset(); iteration_done_ = false; } } // ------------------------------------------------------------------------- SafeStackTraceFrameIterator::SafeStackTraceFrameIterator( Isolate* isolate, Address fp, Address sp, Address low_bound, Address high_bound) : SafeJavaScriptFrameIterator(isolate, fp, sp, low_bound, high_bound) { if (!done() && !frame()->is_java_script()) Advance(); } void SafeStackTraceFrameIterator::Advance() { while (true) { SafeJavaScriptFrameIterator::Advance(); if (done()) return; if (frame()->is_java_script()) return; } } Code* StackFrame::GetSafepointData(Isolate* isolate, Address inner_pointer, SafepointEntry* safepoint_entry, unsigned* stack_slots) { InnerPointerToCodeCache::InnerPointerToCodeCacheEntry* entry = isolate->inner_pointer_to_code_cache()->GetCacheEntry(inner_pointer); if (!entry->safepoint_entry.is_valid()) { entry->safepoint_entry = entry->code->GetSafepointEntry(inner_pointer); ASSERT(entry->safepoint_entry.is_valid()); } else { ASSERT(entry->safepoint_entry.Equals( entry->code->GetSafepointEntry(inner_pointer))); } // Fill in the results and return the code. Code* code = entry->code; *safepoint_entry = entry->safepoint_entry; *stack_slots = code->stack_slots(); return code; } bool StackFrame::HasHandler() const { StackHandlerIterator it(this, top_handler()); return !it.done(); } #ifdef DEBUG static bool GcSafeCodeContains(HeapObject* object, Address addr); #endif void StackFrame::IteratePc(ObjectVisitor* v, Address* pc_address, Code* holder) { Address pc = *pc_address; ASSERT(GcSafeCodeContains(holder, pc)); unsigned pc_offset = static_cast(pc - holder->instruction_start()); Object* code = holder; v->VisitPointer(&code); if (code != holder) { holder = reinterpret_cast(code); pc = holder->instruction_start() + pc_offset; *pc_address = pc; } } void StackFrame::SetReturnAddressLocationResolver( ReturnAddressLocationResolver resolver) { ASSERT(return_address_location_resolver == NULL); return_address_location_resolver = resolver; } StackFrame::Type StackFrame::ComputeType(Isolate* isolate, State* state) { ASSERT(state->fp != NULL); if (StandardFrame::IsArgumentsAdaptorFrame(state->fp)) { return ARGUMENTS_ADAPTOR; } // The marker and function offsets overlap. If the marker isn't a // smi then the frame is a JavaScript frame -- and the marker is // really the function. const int offset = StandardFrameConstants::kMarkerOffset; Object* marker = Memory::Object_at(state->fp + offset); if (!marker->IsSmi()) { // If we're using a "safe" stack iterator, we treat optimized // frames as normal JavaScript frames to avoid having to look // into the heap to determine the state. This is safe as long // as nobody tries to GC... if (SafeStackFrameIterator::is_active(isolate)) return JAVA_SCRIPT; Code::Kind kind = GetContainingCode(isolate, *(state->pc_address))->kind(); ASSERT(kind == Code::FUNCTION || kind == Code::OPTIMIZED_FUNCTION); return (kind == Code::OPTIMIZED_FUNCTION) ? OPTIMIZED : JAVA_SCRIPT; } return static_cast(Smi::cast(marker)->value()); } StackFrame::Type StackFrame::GetCallerState(State* state) const { ComputeCallerState(state); return ComputeType(isolate(), state); } Address StackFrame::UnpaddedFP() const { #if defined(V8_TARGET_ARCH_IA32) if (!is_optimized()) return fp(); int32_t alignment_state = Memory::int32_at( fp() + JavaScriptFrameConstants::kDynamicAlignmentStateOffset); return (alignment_state == kAlignmentPaddingPushed) ? (fp() + kPointerSize) : fp(); #else return fp(); #endif } Code* EntryFrame::unchecked_code() const { return HEAP->js_entry_code(); } void EntryFrame::ComputeCallerState(State* state) const { GetCallerState(state); } void EntryFrame::SetCallerFp(Address caller_fp) { const int offset = EntryFrameConstants::kCallerFPOffset; Memory::Address_at(this->fp() + offset) = caller_fp; } StackFrame::Type EntryFrame::GetCallerState(State* state) const { const int offset = EntryFrameConstants::kCallerFPOffset; Address fp = Memory::Address_at(this->fp() + offset); return ExitFrame::GetStateForFramePointer(fp, state); } Code* EntryConstructFrame::unchecked_code() const { return HEAP->js_construct_entry_code(); } Object*& ExitFrame::code_slot() const { const int offset = ExitFrameConstants::kCodeOffset; return Memory::Object_at(fp() + offset); } Code* ExitFrame::unchecked_code() const { return reinterpret_cast(code_slot()); } void ExitFrame::ComputeCallerState(State* state) const { // Set up the caller state. state->sp = caller_sp(); state->fp = Memory::Address_at(fp() + ExitFrameConstants::kCallerFPOffset); state->pc_address = ResolveReturnAddressLocation( reinterpret_cast(fp() + ExitFrameConstants::kCallerPCOffset)); } void ExitFrame::SetCallerFp(Address caller_fp) { Memory::Address_at(fp() + ExitFrameConstants::kCallerFPOffset) = caller_fp; } void ExitFrame::Iterate(ObjectVisitor* v) const { // The arguments are traversed as part of the expression stack of // the calling frame. IteratePc(v, pc_address(), LookupCode()); v->VisitPointer(&code_slot()); } Address ExitFrame::GetCallerStackPointer() const { return fp() + ExitFrameConstants::kCallerSPDisplacement; } StackFrame::Type ExitFrame::GetStateForFramePointer(Address fp, State* state) { if (fp == 0) return NONE; Address sp = ComputeStackPointer(fp); FillState(fp, sp, state); ASSERT(*state->pc_address != NULL); return EXIT; } void ExitFrame::FillState(Address fp, Address sp, State* state) { state->sp = sp; state->fp = fp; state->pc_address = ResolveReturnAddressLocation( reinterpret_cast(sp - 1 * kPointerSize)); } Address StandardFrame::GetExpressionAddress(int n) const { const int offset = StandardFrameConstants::kExpressionsOffset; return fp() + offset - n * kPointerSize; } Object* StandardFrame::GetExpression(Address fp, int index) { return Memory::Object_at(GetExpressionAddress(fp, index)); } Address StandardFrame::GetExpressionAddress(Address fp, int n) { const int offset = StandardFrameConstants::kExpressionsOffset; return fp + offset - n * kPointerSize; } int StandardFrame::ComputeExpressionsCount() const { const int offset = StandardFrameConstants::kExpressionsOffset + kPointerSize; Address base = fp() + offset; Address limit = sp(); ASSERT(base >= limit); // stack grows downwards // Include register-allocated locals in number of expressions. return static_cast((base - limit) / kPointerSize); } void StandardFrame::ComputeCallerState(State* state) const { state->sp = caller_sp(); state->fp = caller_fp(); state->pc_address = ResolveReturnAddressLocation( reinterpret_cast(ComputePCAddress(fp()))); } void StandardFrame::SetCallerFp(Address caller_fp) { Memory::Address_at(fp() + StandardFrameConstants::kCallerFPOffset) = caller_fp; } bool StandardFrame::IsExpressionInsideHandler(int n) const { Address address = GetExpressionAddress(n); for (StackHandlerIterator it(this, top_handler()); !it.done(); it.Advance()) { if (it.handler()->includes(address)) return true; } return false; } void StandardFrame::IterateCompiledFrame(ObjectVisitor* v) const { // Make sure that we're not doing "safe" stack frame iteration. We cannot // possibly find pointers in optimized frames in that state. ASSERT(!SafeStackFrameIterator::is_active(isolate())); // Compute the safepoint information. unsigned stack_slots = 0; SafepointEntry safepoint_entry; Code* code = StackFrame::GetSafepointData( isolate(), pc(), &safepoint_entry, &stack_slots); unsigned slot_space = stack_slots * kPointerSize; // Visit the outgoing parameters. Object** parameters_base = &Memory::Object_at(sp()); Object** parameters_limit = &Memory::Object_at( fp() + JavaScriptFrameConstants::kFunctionOffset - slot_space); // Visit the parameters that may be on top of the saved registers. if (safepoint_entry.argument_count() > 0) { v->VisitPointers(parameters_base, parameters_base + safepoint_entry.argument_count()); parameters_base += safepoint_entry.argument_count(); } // Skip saved double registers. if (safepoint_entry.has_doubles()) { // Number of doubles not known at snapshot time. ASSERT(!Serializer::enabled()); parameters_base += DoubleRegister::NumAllocatableRegisters() * kDoubleSize / kPointerSize; } // Visit the registers that contain pointers if any. if (safepoint_entry.HasRegisters()) { for (int i = kNumSafepointRegisters - 1; i >=0; i--) { if (safepoint_entry.HasRegisterAt(i)) { int reg_stack_index = MacroAssembler::SafepointRegisterStackIndex(i); v->VisitPointer(parameters_base + reg_stack_index); } } // Skip the words containing the register values. parameters_base += kNumSafepointRegisters; } // We're done dealing with the register bits. uint8_t* safepoint_bits = safepoint_entry.bits(); safepoint_bits += kNumSafepointRegisters >> kBitsPerByteLog2; // Visit the rest of the parameters. v->VisitPointers(parameters_base, parameters_limit); // Visit pointer spill slots and locals. for (unsigned index = 0; index < stack_slots; index++) { int byte_index = index >> kBitsPerByteLog2; int bit_index = index & (kBitsPerByte - 1); if ((safepoint_bits[byte_index] & (1U << bit_index)) != 0) { v->VisitPointer(parameters_limit + index); } } // Visit the return address in the callee and incoming arguments. IteratePc(v, pc_address(), code); } void StubFrame::Iterate(ObjectVisitor* v) const { IterateCompiledFrame(v); } Code* StubFrame::unchecked_code() const { return static_cast(isolate()->heap()->FindCodeObject(pc())); } Address StubFrame::GetCallerStackPointer() const { return fp() + ExitFrameConstants::kCallerSPDisplacement; } int StubFrame::GetNumberOfIncomingArguments() const { return 0; } void OptimizedFrame::Iterate(ObjectVisitor* v) const { #ifdef DEBUG // Make sure that optimized frames do not contain any stack handlers. StackHandlerIterator it(this, top_handler()); ASSERT(it.done()); #endif IterateCompiledFrame(v); // Visit the context and the function. Object** fixed_base = &Memory::Object_at( fp() + JavaScriptFrameConstants::kFunctionOffset); Object** fixed_limit = &Memory::Object_at(fp()); v->VisitPointers(fixed_base, fixed_limit); } void JavaScriptFrame::SetParameterValue(int index, Object* value) const { Memory::Object_at(GetParameterSlot(index)) = value; } bool JavaScriptFrame::IsConstructor() const { Address fp = caller_fp(); if (has_adapted_arguments()) { // Skip the arguments adaptor frame and look at the real caller. fp = Memory::Address_at(fp + StandardFrameConstants::kCallerFPOffset); } return IsConstructFrame(fp); } int JavaScriptFrame::GetArgumentsLength() const { // If there is an arguments adaptor frame get the arguments length from it. if (has_adapted_arguments()) { return Smi::cast(GetExpression(caller_fp(), 0))->value(); } else { return GetNumberOfIncomingArguments(); } } Code* JavaScriptFrame::unchecked_code() const { JSFunction* function = JSFunction::cast(this->function()); return function->unchecked_code(); } int JavaScriptFrame::GetNumberOfIncomingArguments() const { ASSERT(!SafeStackFrameIterator::is_active(isolate()) && isolate()->heap()->gc_state() == Heap::NOT_IN_GC); JSFunction* function = JSFunction::cast(this->function()); return function->shared()->formal_parameter_count(); } Address JavaScriptFrame::GetCallerStackPointer() const { return fp() + StandardFrameConstants::kCallerSPOffset; } void JavaScriptFrame::GetFunctions(List* functions) { ASSERT(functions->length() == 0); functions->Add(JSFunction::cast(function())); } void JavaScriptFrame::Summarize(List* functions) { ASSERT(functions->length() == 0); Code* code_pointer = LookupCode(); int offset = static_cast(pc() - code_pointer->address()); FrameSummary summary(receiver(), JSFunction::cast(function()), code_pointer, offset, IsConstructor()); functions->Add(summary); } void JavaScriptFrame::PrintTop(FILE* file, bool print_args, bool print_line_number) { // constructor calls HandleScope scope; AssertNoAllocation no_allocation; JavaScriptFrameIterator it; while (!it.done()) { if (it.frame()->is_java_script()) { JavaScriptFrame* frame = it.frame(); if (frame->IsConstructor()) PrintF(file, "new "); // function name Object* maybe_fun = frame->function(); if (maybe_fun->IsJSFunction()) { JSFunction* fun = JSFunction::cast(maybe_fun); fun->PrintName(); Code* js_code = frame->unchecked_code(); Address pc = frame->pc(); int code_offset = static_cast(pc - js_code->instruction_start()); PrintF("+%d", code_offset); SharedFunctionInfo* shared = fun->shared(); if (print_line_number) { Code* code = Code::cast( v8::internal::Isolate::Current()->heap()->FindCodeObject(pc)); int source_pos = code->SourcePosition(pc); Object* maybe_script = shared->script(); if (maybe_script->IsScript()) { Handle