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dart / sdk.git / 83735546dbc6ee32909fbb2e86e20365c114822e / . / runtime / vm / profiler.cc
blob: c41f051ef4b20c68e5bc78617928f70e3694237f [file] [log] [blame]
// Copyright (c) 2013, 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 "platform/address_sanitizer.h"
#include "platform/memory_sanitizer.h"
#include "platform/utils.h"
#include "vm/allocation.h"
#include "vm/atomic.h"
#include "vm/code_patcher.h"
#include "vm/debugger.h"
#include "vm/instructions.h"
#include "vm/isolate.h"
#include "vm/json_stream.h"
#include "vm/lockers.h"
#include "vm/message_handler.h"
#include "vm/native_symbol.h"
#include "vm/object.h"
#include "vm/os.h"
#include "vm/profiler.h"
#include "vm/reusable_handles.h"
#include "vm/signal_handler.h"
#include "vm/simulator.h"
#include "vm/stack_frame.h"
namespace dart {
static const intptr_t kSampleSize = 8;
static const intptr_t kMaxSamplesPerTick = 4;
DEFINE_FLAG(bool, trace_profiled_isolates, false, "Trace profiled isolates.");
#if defined(HOST_OS_ANDROID) || defined(TARGET_ARCH_ARM64) || \
defined(TARGET_ARCH_ARM) || defined(TARGET_ARCH_MIPS)
DEFINE_FLAG(int,
profile_period,
10000,
"Time between profiler samples in microseconds. Minimum 50.");
#else
DEFINE_FLAG(int,
profile_period,
1000,
"Time between profiler samples in microseconds. Minimum 50.");
#endif
DEFINE_FLAG(int,
max_profile_depth,
kSampleSize* kMaxSamplesPerTick,
"Maximum number stack frames walked. Minimum 1. Maximum 255.");
#if defined(USING_SIMULATOR)
DEFINE_FLAG(bool, profile_vm, true, "Always collect native stack traces.");
#else
DEFINE_FLAG(bool, profile_vm, false, "Always collect native stack traces.");
#endif
#ifndef PRODUCT
bool Profiler::initialized_ = false;
SampleBuffer* Profiler::sample_buffer_ = NULL;
ProfilerCounters Profiler::counters_;
void Profiler::InitOnce() {
// Place some sane restrictions on user controlled flags.
SetSamplePeriod(FLAG_profile_period);
SetSampleDepth(FLAG_max_profile_depth);
Sample::InitOnce();
if (!FLAG_profiler) {
return;
}
ASSERT(!initialized_);
sample_buffer_ = new SampleBuffer();
// Zero counters.
memset(&counters_, 0, sizeof(counters_));
NativeSymbolResolver::InitOnce();
ThreadInterrupter::SetInterruptPeriod(FLAG_profile_period);
ThreadInterrupter::Startup();
initialized_ = true;
}
void Profiler::Shutdown() {
if (!FLAG_profiler) {
return;
}
ASSERT(initialized_);
ThreadInterrupter::Shutdown();
NativeSymbolResolver::ShutdownOnce();
}
void Profiler::SetSampleDepth(intptr_t depth) {
const int kMinimumDepth = 2;
const int kMaximumDepth = 255;
if (depth < kMinimumDepth) {
FLAG_max_profile_depth = kMinimumDepth;
} else if (depth > kMaximumDepth) {
FLAG_max_profile_depth = kMaximumDepth;
} else {
FLAG_max_profile_depth = depth;
}
}
void Profiler::SetSamplePeriod(intptr_t period) {
const int kMinimumProfilePeriod = 50;
if (period < kMinimumProfilePeriod) {
FLAG_profile_period = kMinimumProfilePeriod;
} else {
FLAG_profile_period = period;
}
}
intptr_t Sample::pcs_length_ = 0;
intptr_t Sample::instance_size_ = 0;
void Sample::InitOnce() {
pcs_length_ = kSampleSize;
instance_size_ = sizeof(Sample) + (sizeof(uword) * pcs_length_); // NOLINT.
}
uword* Sample::GetPCArray() const {
return reinterpret_cast<uword*>(reinterpret_cast<uintptr_t>(this) +
sizeof(*this));
}
SampleBuffer::SampleBuffer(intptr_t capacity) {
ASSERT(Sample::instance_size() > 0);
samples_ =
reinterpret_cast<Sample*>(calloc(capacity, Sample::instance_size()));
if (FLAG_trace_profiler) {
OS::Print("Profiler holds %" Pd " samples\n", capacity);
OS::Print("Profiler sample is %" Pd " bytes\n", Sample::instance_size());
OS::Print("Profiler memory usage = %" Pd " bytes\n",
capacity * Sample::instance_size());
}
capacity_ = capacity;
cursor_ = 0;
}
Sample* SampleBuffer::At(intptr_t idx) const {
ASSERT(idx >= 0);
ASSERT(idx < capacity_);
intptr_t offset = idx * Sample::instance_size();
uint8_t* samples = reinterpret_cast<uint8_t*>(samples_);
return reinterpret_cast<Sample*>(samples + offset);
}
intptr_t SampleBuffer::ReserveSampleSlot() {
ASSERT(samples_ != NULL);
uintptr_t cursor = AtomicOperations::FetchAndIncrement(&cursor_);
// Map back into sample buffer range.
cursor = cursor % capacity_;
return cursor;
}
Sample* SampleBuffer::ReserveSample() {
return At(ReserveSampleSlot());
}
Sample* SampleBuffer::ReserveSampleAndLink(Sample* previous) {
ASSERT(previous != NULL);
intptr_t next_index = ReserveSampleSlot();
Sample* next = At(next_index);
next->Init(previous->port(), previous->timestamp(), previous->tid());
next->set_head_sample(false);
// Mark that previous continues at next.
previous->SetContinuationIndex(next_index);
return next;
}
// Attempts to find the true return address when a Dart frame is being setup
// or torn down.
// NOTE: Architecture specific implementations below.
class ReturnAddressLocator : public ValueObject {
public:
ReturnAddressLocator(Sample* sample, const Code& code)
: stack_buffer_(sample->GetStackBuffer()),
pc_(sample->pc()),
code_(Code::ZoneHandle(code.raw())) {
ASSERT(!code_.IsNull());
ASSERT(code_.ContainsInstructionAt(pc()));
}
ReturnAddressLocator(uword pc, uword* stack_buffer, const Code& code)
: stack_buffer_(stack_buffer),
pc_(pc),
code_(Code::ZoneHandle(code.raw())) {
ASSERT(!code_.IsNull());
ASSERT(code_.ContainsInstructionAt(pc_));
}
uword pc() { return pc_; }
// Returns false on failure.
bool LocateReturnAddress(uword* return_address);
// Returns offset into code object.
intptr_t RelativePC() {
ASSERT(pc() >= code_.PayloadStart());
return static_cast<intptr_t>(pc() - code_.PayloadStart());
}
uint8_t* CodePointer(intptr_t offset) {
const intptr_t size = code_.Size();
ASSERT(offset < size);
uint8_t* code_pointer = reinterpret_cast<uint8_t*>(code_.PayloadStart());
code_pointer += offset;
return code_pointer;
}
uword StackAt(intptr_t i) {
ASSERT(i >= 0);
ASSERT(i < Sample::kStackBufferSizeInWords);
return stack_buffer_[i];
}
private:
uword* stack_buffer_;
uword pc_;
const Code& code_;
};
#if defined(TARGET_ARCH_IA32) || defined(TARGET_ARCH_X64)
bool ReturnAddressLocator::LocateReturnAddress(uword* return_address) {
ASSERT(return_address != NULL);
const intptr_t offset = RelativePC();
ASSERT(offset >= 0);
const intptr_t size = code_.Size();
ASSERT(offset < size);
const intptr_t prologue_offset = code_.GetPrologueOffset();
if (offset < prologue_offset) {
// Before the prologue, return address is at the top of the stack.
// TODO(johnmccutchan): Some intrinsics and stubs do not conform to the
// expected stack layout. Use a more robust solution for those code objects.
*return_address = StackAt(0);
return true;
}
// Detect if we are:
// push ebp <--- here
// mov ebp, esp
// on X64 the register names are different but the sequence is the same.
ProloguePattern pp(pc());
if (pp.IsValid()) {
// Stack layout:
// 0 RETURN ADDRESS.
*return_address = StackAt(0);
return true;
}
// Detect if we are:
// push ebp
// mov ebp, esp <--- here
// on X64 the register names are different but the sequence is the same.
SetFramePointerPattern sfpp(pc());
if (sfpp.IsValid()) {
// Stack layout:
// 0 CALLER FRAME POINTER
// 1 RETURN ADDRESS
*return_address = StackAt(1);
return true;
}
// Detect if we are:
// ret <--- here
ReturnPattern rp(pc());
if (rp.IsValid()) {
// Stack layout:
// 0 RETURN ADDRESS.
*return_address = StackAt(0);
return true;
}
return false;
}
#elif defined(TARGET_ARCH_ARM)
bool ReturnAddressLocator::LocateReturnAddress(uword* return_address) {
ASSERT(return_address != NULL);
return false;
}
#elif defined(TARGET_ARCH_ARM64)
bool ReturnAddressLocator::LocateReturnAddress(uword* return_address) {
ASSERT(return_address != NULL);
return false;
}
#elif defined(TARGET_ARCH_MIPS)
bool ReturnAddressLocator::LocateReturnAddress(uword* return_address) {
ASSERT(return_address != NULL);
return false;
}
#elif defined(TARGET_ARCH_DBC)
bool ReturnAddressLocator::LocateReturnAddress(uword* return_address) {
ASSERT(return_address != NULL);
return false;
}
#else
#error ReturnAddressLocator implementation missing for this architecture.
#endif
bool SampleFilter::TimeFilterSample(Sample* sample) {
if ((time_origin_micros_ == -1) || (time_extent_micros_ == -1)) {
// No time filter passed in, always pass.
return true;
}
const int64_t timestamp = sample->timestamp();
int64_t delta = timestamp - time_origin_micros_;
return (delta >= 0) && (delta <= time_extent_micros_);
}
bool SampleFilter::TaskFilterSample(Sample* sample) {
const intptr_t task = static_cast<intptr_t>(sample->thread_task());
if (thread_task_mask_ == kNoTaskFilter) {
return true;
}
return (task & thread_task_mask_) != 0;
}
ClearProfileVisitor::ClearProfileVisitor(Isolate* isolate)
: SampleVisitor(isolate->main_port()) {}
void ClearProfileVisitor::VisitSample(Sample* sample) {
sample->Clear();
}
static void DumpStackFrame(intptr_t frame_index, uword pc) {
Isolate* isolate = Isolate::Current();
if ((isolate != NULL) && isolate->is_runnable()) {
Code& code = Code::Handle(Code::LookupCodeInVmIsolate(pc));
if (!code.IsNull()) {
OS::PrintErr(" [0x%" Pp "] %s\n", pc, code.QualifiedName());
return;
}
code = Code::LookupCode(pc);
if (!code.IsNull()) {
OS::PrintErr(" [0x%" Pp "] %s\n", pc, code.QualifiedName());
return;
}
}
uintptr_t start = 0;
char* native_symbol_name = NativeSymbolResolver::LookupSymbolName(pc, &start);
if (native_symbol_name == NULL) {
OS::PrintErr(" [0x%" Pp "] Unknown symbol\n", pc);
} else {
OS::PrintErr(" [0x%" Pp "] %s\n", pc, native_symbol_name);
NativeSymbolResolver::FreeSymbolName(native_symbol_name);
}
}
class ProfilerStackWalker : public ValueObject {
public:
ProfilerStackWalker(Dart_Port port_id,
Sample* head_sample,
SampleBuffer* sample_buffer,
intptr_t skip_count = 0)
: port_id_(port_id),
sample_(head_sample),
sample_buffer_(sample_buffer),
skip_count_(skip_count),
frames_skipped_(0),
frame_index_(0),
total_frames_(0) {
if (sample_ == NULL) {
ASSERT(sample_buffer_ == NULL);
} else {
ASSERT(sample_buffer_ != NULL);
ASSERT(sample_->head_sample());
}
}
bool Append(uword pc) {
if (frames_skipped_ < skip_count_) {
frames_skipped_++;
return true;
}
if (sample_ == NULL) {
DumpStackFrame(frame_index_, pc);
frame_index_++;
total_frames_++;
return true;
}
if (total_frames_ >= FLAG_max_profile_depth) {
sample_->set_truncated_trace(true);
return false;
}
ASSERT(sample_ != NULL);
if (frame_index_ == kSampleSize) {
Sample* new_sample = sample_buffer_->ReserveSampleAndLink(sample_);
if (new_sample == NULL) {
// Could not reserve new sample- mark this as truncated.
sample_->set_truncated_trace(true);
return false;
}
frame_index_ = 0;
sample_ = new_sample;
}
ASSERT(frame_index_ < kSampleSize);
sample_->SetAt(frame_index_, pc);
frame_index_++;
total_frames_++;
return true;
}
protected:
Dart_Port port_id_;
Sample* sample_;
SampleBuffer* sample_buffer_;
intptr_t skip_count_;
intptr_t frames_skipped_;
intptr_t frame_index_;
intptr_t total_frames_;
};
// Executing Dart code, walk the stack.
class ProfilerDartStackWalker : public ProfilerStackWalker {
public:
ProfilerDartStackWalker(Thread* thread,
Sample* sample,
SampleBuffer* sample_buffer,
uword stack_lower,
uword stack_upper,
uword pc,
uword fp,
uword sp,
bool exited_dart_code,
bool allocation_sample,
intptr_t skip_count = 0)
: ProfilerStackWalker((thread->isolate() != NULL)
? thread->isolate()->main_port()
: ILLEGAL_PORT,
sample,
sample_buffer,
skip_count),
pc_(reinterpret_cast<uword*>(pc)),
fp_(reinterpret_cast<uword*>(fp)),
sp_(reinterpret_cast<uword*>(sp)),
stack_upper_(stack_upper),
stack_lower_(stack_lower),
has_exit_frame_(exited_dart_code) {
if (exited_dart_code) {
StackFrameIterator iterator(StackFrameIterator::kDontValidateFrames,
thread);
pc_ = NULL;
fp_ = NULL;
sp_ = NULL;
if (!iterator.HasNextFrame()) {
return;
}
// Ensure we are able to get to the exit frame.
StackFrame* frame = iterator.NextFrame();
if (!frame->IsExitFrame()) {
return;
}
// Skip the exit frame.
if (!iterator.HasNextFrame()) {
return;
}
frame = iterator.NextFrame();
// Record frame details of the first frame from which we start walking.
pc_ = reinterpret_cast<uword*>(frame->pc());
fp_ = reinterpret_cast<uword*>(frame->fp());
sp_ = reinterpret_cast<uword*>(frame->sp());
}
}
void walk() {
sample_->set_exit_frame_sample(has_exit_frame_);
if (!ValidFramePointer()) {
sample_->set_ignore_sample(true);
return;
}
ASSERT(ValidFramePointer());
uword return_pc = InitialReturnAddress();
if (StubCode::InInvocationStub(return_pc)) {
// Edge case- we have called out from the Invocation Stub but have not
// created the stack frame of the callee. Attempt to locate the exit
// frame before walking the stack.
if (!NextExit() || !ValidFramePointer()) {
// Nothing to sample.
sample_->set_ignore_sample(true);
return;
}
}
while (true) {
if (!Append(reinterpret_cast<uword>(pc_))) {
return;
}
if (!Next()) {
return;
}
}
}
private:
bool Next() {
if (!ValidFramePointer()) {
return false;
}
if (StubCode::InInvocationStub(reinterpret_cast<uword>(pc_))) {
// In invocation stub.
return NextExit();
}
// In regular Dart frame.
uword* new_pc = CallerPC();
// Check if we've moved into the invocation stub.
if (StubCode::InInvocationStub(reinterpret_cast<uword>(new_pc))) {
// New PC is inside invocation stub, skip.
return NextExit();
}
uword* new_fp = CallerFP();
if (!IsCalleeFrameOf(reinterpret_cast<uword>(new_fp),
reinterpret_cast<uword>(fp_))) {
// FP didn't move to a caller (higher address on most architectures).
return false;
}
// Success, update fp and pc.
fp_ = new_fp;
pc_ = new_pc;
return true;
}
bool NextExit() {
if (!ValidFramePointer()) {
return false;
}
uword* new_fp = ExitLink();
if (new_fp == NULL) {
// No exit link.
return false;
}
if (new_fp <= fp_) {
// FP didn't move to a higher address.
return false;
}
if (!ValidFramePointer(new_fp)) {
return false;
}
// Success, update fp and pc.
fp_ = new_fp;
pc_ = CallerPC();
return true;
}
uword InitialReturnAddress() const {
ASSERT(sp_ != NULL);
// MSan/ASan are unaware of frames initialized by generated code.
MSAN_UNPOISON(sp_, kWordSize);
ASAN_UNPOISON(sp_, kWordSize);
return *(sp_);
}
uword* CallerPC() const {
ASSERT(fp_ != NULL);
uword* caller_pc_ptr = fp_ + kSavedCallerPcSlotFromFp;
// MSan/ASan are unaware of frames initialized by generated code.
MSAN_UNPOISON(caller_pc_ptr, kWordSize);
ASAN_UNPOISON(caller_pc_ptr, kWordSize);
return reinterpret_cast<uword*>(*caller_pc_ptr);
}
uword* CallerFP() const {
ASSERT(fp_ != NULL);
uword* caller_fp_ptr = fp_ + kSavedCallerFpSlotFromFp;
// MSan/ASan are unaware of frames initialized by generated code.
MSAN_UNPOISON(caller_fp_ptr, kWordSize);
ASAN_UNPOISON(caller_fp_ptr, kWordSize);
return reinterpret_cast<uword*>(*caller_fp_ptr);
}
uword* ExitLink() const {
ASSERT(fp_ != NULL);
uword* exit_link_ptr = fp_ + kExitLinkSlotFromEntryFp;
// MSan/ASan are unaware of frames initialized by generated code.
MSAN_UNPOISON(exit_link_ptr, kWordSize);
ASAN_UNPOISON(exit_link_ptr, kWordSize);
return reinterpret_cast<uword*>(*exit_link_ptr);
}
bool ValidFramePointer() const { return ValidFramePointer(fp_); }
bool ValidFramePointer(uword* fp) const {
if (fp == NULL) {
return false;
}
uword cursor = reinterpret_cast<uword>(fp);
cursor += sizeof(fp);
return (cursor >= stack_lower_) && (cursor < stack_upper_);
}
uword* pc_;
uword* fp_;
uword* sp_;
const uword stack_upper_;
const uword stack_lower_;
bool has_exit_frame_;
};
// If the VM is compiled without frame pointers (which is the default on
// recent GCC versions with optimizing enabled) the stack walking code may
// fail.
//
class ProfilerNativeStackWalker : public ProfilerStackWalker {
public:
ProfilerNativeStackWalker(Dart_Port port_id,
Sample* sample,
SampleBuffer* sample_buffer,
uword stack_lower,
uword stack_upper,
uword pc,
uword fp,
uword sp,
intptr_t skip_count = 0)
: ProfilerStackWalker(port_id, sample, sample_buffer, skip_count),
stack_upper_(stack_upper),
original_pc_(pc),
original_fp_(fp),
original_sp_(sp),
lower_bound_(stack_lower) {}
void walk() {
const uword kMaxStep = VirtualMemory::PageSize();
Append(original_pc_);
uword* pc = reinterpret_cast<uword*>(original_pc_);
uword* fp = reinterpret_cast<uword*>(original_fp_);
uword* previous_fp = fp;
uword gap = original_fp_ - original_sp_;
if (gap >= kMaxStep) {
// Gap between frame pointer and stack pointer is
// too large.
return;
}
if (!ValidFramePointer(fp)) {
return;
}
while (true) {
if (!Append(reinterpret_cast<uword>(pc))) {
return;
}
pc = CallerPC(fp);
previous_fp = fp;
fp = CallerFP(fp);
if (fp == NULL) {
return;
}
if (fp <= previous_fp) {
// Frame pointer did not move to a higher address.
return;
}
gap = fp - previous_fp;
if (gap >= kMaxStep) {
// Frame pointer step is too large.
return;
}
if (!ValidFramePointer(fp)) {
// Frame pointer is outside of isolate stack boundary.
return;
}
// Move the lower bound up.
lower_bound_ = reinterpret_cast<uword>(fp);
}
}
private:
uword* CallerPC(uword* fp) const {
ASSERT(fp != NULL);
uword* caller_pc_ptr = fp + kSavedCallerPcSlotFromFp;
// This may actually be uninitialized, by design (see class comment above).
MSAN_UNPOISON(caller_pc_ptr, kWordSize);
ASAN_UNPOISON(caller_pc_ptr, kWordSize);
return reinterpret_cast<uword*>(*caller_pc_ptr);
}
uword* CallerFP(uword* fp) const {
ASSERT(fp != NULL);
uword* caller_fp_ptr = fp + kSavedCallerFpSlotFromFp;
// This may actually be uninitialized, by design (see class comment above).
MSAN_UNPOISON(caller_fp_ptr, kWordSize);
ASAN_UNPOISON(caller_fp_ptr, kWordSize);
return reinterpret_cast<uword*>(*caller_fp_ptr);
}
bool ValidFramePointer(uword* fp) const {
if (fp == NULL) {
return false;
}
uword cursor = reinterpret_cast<uword>(fp);
cursor += sizeof(fp);
bool r = (cursor >= lower_bound_) && (cursor < stack_upper_);
return r;
}
const uword stack_upper_;
const uword original_pc_;
const uword original_fp_;
const uword original_sp_;
uword lower_bound_;
};
static void CopyStackBuffer(Sample* sample, uword sp_addr) {
ASSERT(sample != NULL);
uword* sp = reinterpret_cast<uword*>(sp_addr);
uword* buffer = sample->GetStackBuffer();
if (sp != NULL) {
for (intptr_t i = 0; i < Sample::kStackBufferSizeInWords; i++) {
MSAN_UNPOISON(sp, kWordSize);
ASAN_UNPOISON(sp, kWordSize);
buffer[i] = *sp;
sp++;
}
}
}
#if defined(HOST_OS_WINDOWS)
// On Windows this code is synchronously executed from the thread interrupter
// thread. This means we can safely have a static fault_address.
static uword fault_address = 0;
static LONG GuardPageExceptionFilter(EXCEPTION_POINTERS* ep) {
fault_address = 0;
if (ep->ExceptionRecord->ExceptionCode != STATUS_GUARD_PAGE_VIOLATION) {
return EXCEPTION_CONTINUE_SEARCH;
}
// https://goo.gl/p5Fe10
fault_address = ep->ExceptionRecord->ExceptionInformation[1];
// Read access.
ASSERT(ep->ExceptionRecord->ExceptionInformation[0] == 0);
return EXCEPTION_EXECUTE_HANDLER;
}
#endif
// All memory access done to collect the sample is performed in CollectSample.
static void CollectSample(Isolate* isolate,
bool exited_dart_code,
bool in_dart_code,
Sample* sample,
ProfilerNativeStackWalker* native_stack_walker,
ProfilerDartStackWalker* dart_stack_walker,
uword pc,
uword fp,
uword sp,
ProfilerCounters* counters) {
ASSERT(counters != NULL);
#if defined(HOST_OS_WINDOWS)
// Use structured exception handling to trap guard page access on Windows.
__try {
#endif
if (in_dart_code) {
// We can only trust the stack pointer if we are executing Dart code.
// See http://dartbug.com/20421 for details.
CopyStackBuffer(sample, sp);
}
if (FLAG_profile_vm) {
// Always walk the native stack collecting both native and Dart frames.
AtomicOperations::IncrementInt64By(&counters->stack_walker_native, 1);
native_stack_walker->walk();
} else if (StubCode::HasBeenInitialized() && exited_dart_code) {
AtomicOperations::IncrementInt64By(&counters->stack_walker_dart_exit, 1);
// We have a valid exit frame info, use the Dart stack walker.
dart_stack_walker->walk();
} else if (StubCode::HasBeenInitialized() && in_dart_code) {
AtomicOperations::IncrementInt64By(&counters->stack_walker_dart, 1);
// We are executing Dart code. We have frame pointers.
dart_stack_walker->walk();
} else {
AtomicOperations::IncrementInt64By(&counters->stack_walker_none, 1);
sample->SetAt(0, pc);
}
#if defined(HOST_OS_WINDOWS)
// Use structured exception handling to trap guard page access.
} __except (GuardPageExceptionFilter(GetExceptionInformation())) { // NOLINT
// Sample collection triggered a guard page fault:
// 1) discard entire sample.
sample->set_ignore_sample(true);
// 2) Reenable guard bit on page that triggered the fault.
// https://goo.gl/5mCsXW
DWORD new_protect = PAGE_READWRITE | PAGE_GUARD;
DWORD old_protect = 0;
BOOL success =
VirtualProtect(reinterpret_cast<void*>(fault_address),
sizeof(fault_address), new_protect, &old_protect);
USE(success);
ASSERT(success);
ASSERT(old_protect == PAGE_READWRITE);
}
#endif
}
static bool ValidateThreadStackBounds(uintptr_t fp,
uintptr_t sp,
uword stack_lower,
uword stack_upper) {
if (stack_lower >= stack_upper) {
// Stack boundary is invalid.
return false;
}
if ((sp < stack_lower) || (sp >= stack_upper)) {
// Stack pointer is outside thread's stack boundary.
return false;
}
if ((fp < stack_lower) || (fp >= stack_upper)) {
// Frame pointer is outside threads's stack boundary.
return false;
}
return true;
}
// Get |isolate|'s stack boundary and verify that |sp| and |fp| are within
// it. If |get_os_thread_bounds| is true then if |isolate| stackbounds are
// not available we fallback to using underlying OS thread bounds. This only
// works for the current thread.
// Return |false| if anything looks suspicious.
static bool GetAndValidateThreadStackBounds(Thread* thread,
uintptr_t fp,
uintptr_t sp,
uword* stack_lower,
uword* stack_upper,
bool get_os_thread_bounds = false) {
OSThread* os_thread = NULL;
if (thread != NULL) {
os_thread = thread->os_thread();
} else {
os_thread = OSThread::Current();
}
ASSERT(os_thread != NULL);
ASSERT(stack_lower != NULL);
ASSERT(stack_upper != NULL);
ASSERT(!get_os_thread_bounds || (Thread::Current() == thread));
#if defined(USING_SIMULATOR)
const bool use_simulator_stack_bounds = thread->IsExecutingDartCode();
if (use_simulator_stack_bounds) {
Isolate* isolate = thread->isolate();
ASSERT(isolate != NULL);
Simulator* simulator = isolate->simulator();
*stack_lower = simulator->StackBase();
*stack_upper = simulator->StackTop();
}
#else
const bool use_simulator_stack_bounds = false;
#endif
if (!use_simulator_stack_bounds &&
!os_thread->GetProfilerStackBounds(stack_lower, stack_upper) &&
!(get_os_thread_bounds &&
OSThread::GetCurrentStackBounds(stack_lower, stack_upper))) {
// Could not get stack boundary.
return false;
}
if ((*stack_lower == 0) || (*stack_upper == 0)) {
return false;
}
if (!use_simulator_stack_bounds && (sp > *stack_lower)) {
// The stack pointer gives us a tighter lower bound.
*stack_lower = sp;
}
return ValidateThreadStackBounds(fp, sp, *stack_lower, *stack_upper);
}
// Some simple sanity checking of |pc|, |fp|, and |sp|.
static bool InitialRegisterCheck(uintptr_t pc, uintptr_t fp, uintptr_t sp) {
if ((sp == 0) || (fp == 0) || (pc == 0)) {
// None of these registers should be zero.
return false;
}
if (sp > fp) {
// Assuming the stack grows down, we should never have a stack pointer above
// the frame pointer.
return false;
}
return true;
}
static Sample* SetupSample(Thread* thread,
SampleBuffer* sample_buffer,
ThreadId tid) {
ASSERT(thread != NULL);
Isolate* isolate = thread->isolate();
ASSERT(sample_buffer != NULL);
Sample* sample = sample_buffer->ReserveSample();
sample->Init(isolate->main_port(), OS::GetCurrentMonotonicMicros(), tid);
uword vm_tag = thread->vm_tag();
#if defined(USING_SIMULATOR) && !defined(TARGET_ARCH_DBC)
// When running in the simulator, the runtime entry function address
// (stored as the vm tag) is the address of a redirect function.
// Attempt to find the real runtime entry function address and use that.
uword redirect_vm_tag = Simulator::FunctionForRedirect(vm_tag);
if (redirect_vm_tag != 0) {
vm_tag = redirect_vm_tag;
}
#endif
sample->set_vm_tag(vm_tag);
sample->set_user_tag(isolate->user_tag());
sample->set_thread_task(thread->task_kind());
return sample;
}
static Sample* SetupSampleNative(SampleBuffer* sample_buffer, ThreadId tid) {
Sample* sample = sample_buffer->ReserveSample();
sample->Init(ILLEGAL_PORT, OS::GetCurrentMonotonicMicros(), tid);
sample->set_is_native_allocation_sample(true);
Thread* thread = Thread::Current();
// Note: setting thread task in order to be consistent with other samples. The
// task kind is not used by NativeAllocationSampleFilter for filtering
// purposes as some samples may be collected when no thread exists.
if (thread != NULL) {
sample->set_thread_task(thread->task_kind());
}
return sample;
}
static bool CheckIsolate(Isolate* isolate) {
if ((isolate == NULL) || (Dart::vm_isolate() == NULL)) {
// No isolate.
return false;
}
return isolate != Dart::vm_isolate();
}
void Profiler::DumpStackTrace(void* context) {
#if defined(HOST_OS_LINUX) || defined(HOST_OS_MACOS)
ucontext_t* ucontext = reinterpret_cast<ucontext_t*>(context);
mcontext_t mcontext = ucontext->uc_mcontext;
uword pc = SignalHandler::GetProgramCounter(mcontext);
uword fp = SignalHandler::GetFramePointer(mcontext);
uword sp = SignalHandler::GetCStackPointer(mcontext);
DumpStackTrace(sp, fp, pc);
#else
// TODO(fschneider): Add support for more platforms.
// Do nothing on unsupported platforms.
#endif
}
void Profiler::DumpStackTrace() {
uintptr_t sp = Thread::GetCurrentStackPointer();
uintptr_t fp = 0;
uintptr_t pc = OS::GetProgramCounter();
COPY_FP_REGISTER(fp);
DumpStackTrace(sp, fp, pc);
}
void Profiler::DumpStackTrace(uword sp, uword fp, uword pc) {
// Allow only one stack trace to prevent recursively printing stack traces if
// we hit an assert while printing the stack.
static uintptr_t started_dump = 0;
if (AtomicOperations::FetchAndIncrement(&started_dump) != 0) {
OS::PrintErr("Aborting re-entrant request for stack trace.\n");
return;
}
Thread* thread = Thread::Current();
if (thread == NULL) {
return;
}
OSThread* os_thread = thread->os_thread();
ASSERT(os_thread != NULL);
Isolate* isolate = thread->isolate();
if (!CheckIsolate(isolate)) {
return;
}
OS::PrintErr("Dumping native stack trace for thread %" Px "\n",
OSThread::ThreadIdToIntPtr(os_thread->trace_id()));
uword stack_lower = 0;
uword stack_upper = 0;
if (!InitialRegisterCheck(pc, fp, sp)) {
OS::PrintErr("Stack dump aborted because InitialRegisterCheck.\n");
return;
}
if (!GetAndValidateThreadStackBounds(thread, fp, sp, &stack_lower,
&stack_upper,
/*get_os_thread_bounds=*/true)) {
OS::PrintErr(
"Stack dump aborted because GetAndValidateThreadStackBounds.\n");
return;
}
ProfilerNativeStackWalker native_stack_walker(
(isolate != NULL) ? isolate->main_port() : ILLEGAL_PORT, NULL, NULL,
stack_lower, stack_upper, pc, fp, sp);
native_stack_walker.walk();
OS::PrintErr("-- End of DumpStackTrace\n");
}
void Profiler::SampleAllocation(Thread* thread, intptr_t cid) {
ASSERT(thread != NULL);
OSThread* os_thread = thread->os_thread();
ASSERT(os_thread != NULL);
Isolate* isolate = thread->isolate();
if (!CheckIsolate(isolate)) {
return;
}
const bool exited_dart_code = thread->HasExitedDartCode();
SampleBuffer* sample_buffer = Profiler::sample_buffer();
if (sample_buffer == NULL) {
// Profiler not initialized.
return;
}
uintptr_t sp = Thread::GetCurrentStackPointer();
uintptr_t fp = 0;
uintptr_t pc = OS::GetProgramCounter();
COPY_FP_REGISTER(fp);
uword stack_lower = 0;
uword stack_upper = 0;
if (!InitialRegisterCheck(pc, fp, sp)) {
return;
}
if (!GetAndValidateThreadStackBounds(thread, fp, sp, &stack_lower,
&stack_upper)) {
// Could not get stack boundary.
return;
}
Sample* sample = SetupSample(thread, sample_buffer, os_thread->trace_id());
sample->SetAllocationCid(cid);
if (FLAG_profile_vm) {
ProfilerNativeStackWalker native_stack_walker(
(isolate != NULL) ? isolate->main_port() : ILLEGAL_PORT, sample,
sample_buffer, stack_lower, stack_upper, pc, fp, sp);
native_stack_walker.walk();
} else if (exited_dart_code) {
ProfilerDartStackWalker dart_exit_stack_walker(
thread, sample, sample_buffer, stack_lower, stack_upper, pc, fp, sp,
exited_dart_code, true);
dart_exit_stack_walker.walk();
} else {
// Fall back.
uintptr_t pc = OS::GetProgramCounter();
Sample* sample = SetupSample(thread, sample_buffer, os_thread->trace_id());
sample->SetAllocationCid(cid);
sample->SetAt(0, pc);
}
}
Sample* Profiler::SampleNativeAllocation(intptr_t skip_count,
uword address,
uintptr_t allocation_size) {
SampleBuffer* sample_buffer = Profiler::sample_buffer();
if (sample_buffer == NULL) {
return NULL;
}
uintptr_t sp = Thread::GetCurrentStackPointer();
uintptr_t fp = 0;
uintptr_t pc = OS::GetProgramCounter();
COPY_FP_REGISTER(fp);
uword stack_lower = 0;
uword stack_upper = 0;
if (!InitialRegisterCheck(pc, fp, sp)) {
AtomicOperations::IncrementInt64By(
&counters_.failure_native_allocation_sample, 1);
return NULL;
}
if (!(OSThread::GetCurrentStackBounds(&stack_lower, &stack_upper) &&
ValidateThreadStackBounds(fp, sp, stack_lower, stack_upper))) {
// Could not get stack boundary.
AtomicOperations::IncrementInt64By(
&counters_.failure_native_allocation_sample, 1);
return NULL;
}
OSThread* os_thread = OSThread::Current();
Sample* sample = SetupSampleNative(sample_buffer, os_thread->trace_id());
sample->set_native_allocation_address(address);
sample->set_native_allocation_size_bytes(allocation_size);
ProfilerNativeStackWalker native_stack_walker(
ILLEGAL_PORT, sample, sample_buffer, stack_lower, stack_upper, pc, fp, sp,
skip_count);
native_stack_walker.walk();
return sample;
}
void Profiler::SampleThreadSingleFrame(Thread* thread, uintptr_t pc) {
ASSERT(thread != NULL);
OSThread* os_thread = thread->os_thread();
ASSERT(os_thread != NULL);
Isolate* isolate = thread->isolate();
SampleBuffer* sample_buffer = Profiler::sample_buffer();
if (sample_buffer == NULL) {
// Profiler not initialized.
return;
}
// Setup sample.
Sample* sample = SetupSample(thread, sample_buffer, os_thread->trace_id());
// Increment counter for vm tag.
VMTagCounters* counters = isolate->vm_tag_counters();
ASSERT(counters != NULL);
if (thread->IsMutatorThread()) {
counters->Increment(sample->vm_tag());
}
// Write the single pc value.
sample->SetAt(0, pc);
}
void Profiler::SampleThread(Thread* thread,
const InterruptedThreadState& state) {
ASSERT(thread != NULL);
OSThread* os_thread = thread->os_thread();
ASSERT(os_thread != NULL);
Isolate* isolate = thread->isolate();
// Thread is not doing VM work.
if (thread->task_kind() == Thread::kUnknownTask) {
AtomicOperations::IncrementInt64By(&counters_.bail_out_unknown_task, 1);
return;
}
if (StubCode::HasBeenInitialized() && StubCode::InJumpToFrameStub(state.pc)) {
// The JumpToFrame stub manually adjusts the stack pointer, frame
// pointer, and some isolate state. It is not safe to walk the
// stack when executing this stub.
AtomicOperations::IncrementInt64By(
&counters_.bail_out_jump_to_exception_handler, 1);
return;
}
const bool in_dart_code = thread->IsExecutingDartCode();
uintptr_t sp = 0;
uintptr_t fp = state.fp;
uintptr_t pc = state.pc;
#if defined(USING_SIMULATOR)
Simulator* simulator = NULL;
#endif
if (in_dart_code) {
// If we're in Dart code, use the Dart stack pointer.
#if defined(TARGET_ARCH_DBC)
simulator = isolate->simulator();
sp = simulator->get_sp();
fp = simulator->get_fp();
pc = simulator->get_pc();
#elif defined(USING_SIMULATOR)
simulator = isolate->simulator();
sp = simulator->get_register(SPREG);
fp = simulator->get_register(FPREG);
pc = simulator->get_pc();
#else
sp = state.dsp;
#endif
} else {
// If we're in runtime code, use the C stack pointer.
sp = state.csp;
}
if (!CheckIsolate(isolate)) {
AtomicOperations::IncrementInt64By(&counters_.bail_out_check_isolate, 1);
return;
}
if (thread->IsMutatorThread() && isolate->IsDeoptimizing()) {
AtomicOperations::IncrementInt64By(
&counters_.single_frame_sample_deoptimizing, 1);
SampleThreadSingleFrame(thread, pc);
return;
}
if (!InitialRegisterCheck(pc, fp, sp)) {
AtomicOperations::IncrementInt64By(
&counters_.single_frame_sample_register_check, 1);
SampleThreadSingleFrame(thread, pc);
return;
}
uword stack_lower = 0;
uword stack_upper = 0;
if (!GetAndValidateThreadStackBounds(thread, fp, sp, &stack_lower,
&stack_upper)) {
AtomicOperations::IncrementInt64By(
&counters_.single_frame_sample_get_and_validate_stack_bounds, 1);
// Could not get stack boundary.
SampleThreadSingleFrame(thread, pc);
return;
}
// At this point we have a valid stack boundary for this isolate and
// know that our initial stack and frame pointers are within the boundary.
SampleBuffer* sample_buffer = Profiler::sample_buffer();
if (sample_buffer == NULL) {
// Profiler not initialized.
return;
}
// Setup sample.
Sample* sample = SetupSample(thread, sample_buffer, os_thread->trace_id());
// Increment counter for vm tag.
VMTagCounters* counters = isolate->vm_tag_counters();
ASSERT(counters != NULL);
if (thread->IsMutatorThread()) {
counters->Increment(sample->vm_tag());
}
ProfilerNativeStackWalker native_stack_walker(
(isolate != NULL) ? isolate->main_port() : ILLEGAL_PORT, sample,
sample_buffer, stack_lower, stack_upper, pc, fp, sp);
const bool exited_dart_code = thread->HasExitedDartCode();
ProfilerDartStackWalker dart_stack_walker(thread, sample, sample_buffer,
stack_lower, stack_upper, pc, fp,
sp, exited_dart_code, false);
// All memory access is done inside CollectSample.
CollectSample(isolate, exited_dart_code, in_dart_code, sample,
&native_stack_walker, &dart_stack_walker, pc, fp, sp,
&counters_);
}
CodeDescriptor::CodeDescriptor(const Code& code) : code_(code) {
ASSERT(!code_.IsNull());
}
uword CodeDescriptor::Start() const {
return code_.PayloadStart();
}
uword CodeDescriptor::Size() const {
return code_.Size();
}
int64_t CodeDescriptor::CompileTimestamp() const {
return code_.compile_timestamp();
}
CodeLookupTable::CodeLookupTable(Thread* thread) {
Build(thread);
}
class CodeLookupTableBuilder : public ObjectVisitor {
public:
explicit CodeLookupTableBuilder(CodeLookupTable* table) : table_(table) {
ASSERT(table_ != NULL);
}
~CodeLookupTableBuilder() {}
void VisitObject(RawObject* raw_obj) {
uword tags = raw_obj->ptr()->tags_;
if (RawObject::ClassIdTag::decode(tags) == kCodeCid) {
RawCode* raw_code = reinterpret_cast<RawCode*>(raw_obj);
const Code& code = Code::Handle(raw_code);
ASSERT(!code.IsNull());
const Instructions& instructions =
Instructions::Handle(code.instructions());
ASSERT(!instructions.IsNull());
table_->Add(code);
}
}
private:
CodeLookupTable* table_;
};
void CodeLookupTable::Build(Thread* thread) {
ASSERT(thread != NULL);
Isolate* isolate = thread->isolate();
ASSERT(isolate != NULL);
Isolate* vm_isolate = Dart::vm_isolate();
ASSERT(vm_isolate != NULL);
// Clear.
code_objects_.Clear();
// Add all found Code objects.
CodeLookupTableBuilder cltb(this);
vm_isolate->heap()->IterateOldObjects(&cltb);
isolate->heap()->IterateOldObjects(&cltb);
// Sort by entry.
code_objects_.Sort(CodeDescriptor::Compare);
#if defined(DEBUG)
if (length() <= 1) {
return;
}
ASSERT(FindCode(0) == NULL);
ASSERT(FindCode(~0) == NULL);
// Sanity check that we don't have duplicate entries and that the entries
// are sorted.
for (intptr_t i = 0; i < length() - 1; i++) {
const CodeDescriptor* a = At(i);
const CodeDescriptor* b = At(i + 1);
ASSERT(a->Start() < b->Start());
ASSERT(FindCode(a->Start()) == a);
ASSERT(FindCode(b->Start()) == b);
ASSERT(FindCode(a->Start() + a->Size() - 1) == a);
ASSERT(FindCode(b->Start() + b->Size() - 1) == b);
}
#endif
}
void CodeLookupTable::Add(const Code& code) {
ASSERT(!code.IsNull());
CodeDescriptor* cd = new CodeDescriptor(code);
code_objects_.Add(cd);
}
const CodeDescriptor* CodeLookupTable::FindCode(uword pc) const {
intptr_t first = 0;
intptr_t count = length();
while (count > 0) {
intptr_t current = first;
intptr_t step = count / 2;
current += step;
const CodeDescriptor* cd = At(current);
if (pc >= cd->Start()) {
first = ++current;
count -= step + 1;
} else {
count = step;
}
}
// First points to the first code object whose entry is greater than PC.
// That means the code object we need to check is first - 1.
if (first == 0) {
return NULL;
}
first--;
ASSERT(first >= 0);
ASSERT(first < length());
const CodeDescriptor* cd = At(first);
if (cd->Contains(pc)) {
return cd;
}
return NULL;
}
ProcessedSampleBuffer* SampleBuffer::BuildProcessedSampleBuffer(
SampleFilter* filter) {
ASSERT(filter != NULL);
Thread* thread = Thread::Current();
Zone* zone = thread->zone();
ProcessedSampleBuffer* buffer = new (zone) ProcessedSampleBuffer();
const intptr_t length = capacity();
for (intptr_t i = 0; i < length; i++) {
Sample* sample = At(i);
if (sample->ignore_sample()) {
// Bad sample.
continue;
}
if (!sample->head_sample()) {
// An inner sample in a chain of samples.
continue;
}
// If we're requesting all the native allocation samples, we don't care
// whether or not we're in the same isolate as the sample.
if (sample->port() != filter->port()) {
// Another isolate.
continue;
}
if (sample->timestamp() == 0) {
// Empty.
continue;
}
if (sample->At(0) == 0) {
// No frames.
continue;
}
if (!filter->TimeFilterSample(sample)) {
// Did not pass time filter.
continue;
}
if (!filter->TaskFilterSample(sample)) {
// Did not pass task filter.
continue;
}
if (!filter->FilterSample(sample)) {
// Did not pass filter.
continue;
}
buffer->Add(BuildProcessedSample(sample, buffer->code_lookup_table()));
}
return buffer;
}
ProcessedSample* SampleBuffer::BuildProcessedSample(
Sample* sample,
const CodeLookupTable& clt) {
Thread* thread = Thread::Current();
Zone* zone = thread->zone();
ProcessedSample* processed_sample = new (zone) ProcessedSample();
// Copy state bits from sample.
processed_sample->set_native_allocation_size_bytes(
sample->native_allocation_size_bytes());
processed_sample->set_timestamp(sample->timestamp());
processed_sample->set_tid(sample->tid());
processed_sample->set_vm_tag(sample->vm_tag());
processed_sample->set_user_tag(sample->user_tag());
if (sample->is_allocation_sample()) {
processed_sample->set_allocation_cid(sample->allocation_cid());
}
processed_sample->set_first_frame_executing(!sample->exit_frame_sample());
// Copy stack trace from sample(s).
bool truncated = false;
Sample* current = sample;
while (current != NULL) {
for (intptr_t i = 0; i < kSampleSize; i++) {
if (current->At(i) == 0) {
break;
}
processed_sample->Add(current->At(i));
}
truncated = truncated || current->truncated_trace();
current = Next(current);
}
if (!sample->exit_frame_sample()) {
processed_sample->FixupCaller(clt, sample->pc_marker(),
sample->GetStackBuffer());
}
processed_sample->set_truncated(truncated);
return processed_sample;
}
Sample* SampleBuffer::Next(Sample* sample) {
if (!sample->is_continuation_sample()) return NULL;
Sample* next_sample = At(sample->continuation_index());
// Sanity check.
ASSERT(sample != next_sample);
// Detect invalid chaining.
if (sample->port() != next_sample->port()) {
return NULL;
}
if (sample->timestamp() != next_sample->timestamp()) {
return NULL;
}
if (sample->tid() != next_sample->tid()) {
return NULL;
}
return next_sample;
}
ProcessedSample::ProcessedSample()
: pcs_(kSampleSize),
timestamp_(0),
vm_tag_(0),
user_tag_(0),
allocation_cid_(-1),
truncated_(false),
timeline_trie_(NULL) {}
void ProcessedSample::FixupCaller(const CodeLookupTable& clt,
uword pc_marker,
uword* stack_buffer) {
const CodeDescriptor* cd = clt.FindCode(At(0));
if (cd == NULL) {
// No Dart code.
return;
}
if (cd->CompileTimestamp() > timestamp()) {
// Code compiled after sample. Ignore.
return;
}
CheckForMissingDartFrame(clt, cd, pc_marker, stack_buffer);
}
void ProcessedSample::CheckForMissingDartFrame(const CodeLookupTable& clt,
const CodeDescriptor* cd,
uword pc_marker,
uword* stack_buffer) {
ASSERT(cd != NULL);
const Code& code = Code::Handle(cd->code());
ASSERT(!code.IsNull());
// Some stubs (and intrinsics) do not push a frame onto the stack leaving
// the frame pointer in the caller.
//
// PC -> STUB
// FP -> DART3 <-+
// DART2 <-| <- TOP FRAME RETURN ADDRESS.
// DART1 <-|
// .....
//
// In this case, traversing the linked stack frames will not collect a PC
// inside DART3. The stack will incorrectly be: STUB, DART2, DART1.
// In Dart code, after pushing the FP onto the stack, an IP in the current
// function is pushed onto the stack as well. This stack slot is called
// the PC marker. We can use the PC marker to insert DART3 into the stack
// so that it will correctly be: STUB, DART3, DART2, DART1. Note the
// inserted PC may not accurately reflect the true return address into DART3.
// The pc marker is our current best guess of a return address.
uword return_address = pc_marker;
// Attempt to find a better return address.
ReturnAddressLocator ral(At(0), stack_buffer, code);
if (!ral.LocateReturnAddress(&return_address)) {
ASSERT(return_address == pc_marker);
if (code.GetPrologueOffset() == 0) {
// Code has the prologue at offset 0. The frame is already setup and
// can be trusted.
return;
}
// Could not find a better return address than the pc_marker.
if (code.ContainsInstructionAt(return_address)) {
// PC marker is in the same code as pc, no missing frame.
return;
}
}
if (clt.FindCode(return_address) == NULL) {
// Return address is not from a Dart code object. Do not insert.
return;
}
if (return_address != 0) {
InsertAt(1, return_address);
}
}
ProcessedSampleBuffer::ProcessedSampleBuffer()
: code_lookup_table_(new CodeLookupTable(Thread::Current())) {
ASSERT(code_lookup_table_ != NULL);
}
#endif // !PRODUCT
} // namespace dart