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// Copyright 2016 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "include/libplatform/v8-tracing.h"
#include "src/base/atomicops.h"
#include "src/base/platform/mutex.h"
#include "src/base/platform/time.h"
namespace v8 {
namespace platform {
namespace tracing {
#define MAX_CATEGORY_GROUPS 200
// Parallel arrays g_category_groups and g_category_group_enabled are separate
// so that a pointer to a member of g_category_group_enabled can be easily
// converted to an index into g_category_groups. This allows macros to deal
// only with char enabled pointers from g_category_group_enabled, and we can
// convert internally to determine the category name from the char enabled
// pointer.
const char* g_category_groups[MAX_CATEGORY_GROUPS] = {
"toplevel",
"tracing categories exhausted; must increase MAX_CATEGORY_GROUPS",
"__metadata"};
// The enabled flag is char instead of bool so that the API can be used from C.
unsigned char g_category_group_enabled[MAX_CATEGORY_GROUPS] = {0};
// Indexes here have to match the g_category_groups array indexes above.
const int g_category_categories_exhausted = 1;
// Metadata category not used in V8.
// const int g_category_metadata = 2;
const int g_num_builtin_categories = 3;
// Skip default categories.
v8::base::AtomicWord g_category_index = g_num_builtin_categories;
TracingController::TracingController() {}
TracingController::~TracingController() {
StopTracing();
{
// Free memory for category group names allocated via strdup.
base::LockGuard<base::Mutex> lock(mutex_.get());
for (size_t i = g_category_index - 1; i >= g_num_builtin_categories; --i) {
const char* group = g_category_groups[i];
g_category_groups[i] = nullptr;
free(const_cast<char*>(group));
}
g_category_index = g_num_builtin_categories;
}
}
void TracingController::Initialize(TraceBuffer* trace_buffer) {
trace_buffer_.reset(trace_buffer);
mutex_.reset(new base::Mutex());
}
int64_t TracingController::CurrentTimestampMicroseconds() {
return base::TimeTicks::HighResolutionNow().ToInternalValue();
}
int64_t TracingController::CurrentCpuTimestampMicroseconds() {
return base::ThreadTicks::Now().ToInternalValue();
}
uint64_t TracingController::AddTraceEvent(
char phase, const uint8_t* category_enabled_flag, const char* name,
const char* scope, uint64_t id, uint64_t bind_id, int num_args,
const char** arg_names, const uint8_t* arg_types,
const uint64_t* arg_values,
std::unique_ptr<v8::ConvertableToTraceFormat>* arg_convertables,
unsigned int flags) {
uint64_t handle = 0;
if (mode_ != DISABLED) {
TraceObject* trace_object = trace_buffer_->AddTraceEvent(&handle);
if (trace_object) {
trace_object->Initialize(
phase, category_enabled_flag, name, scope, id, bind_id, num_args,
arg_names, arg_types, arg_values, arg_convertables, flags,
CurrentTimestampMicroseconds(), CurrentCpuTimestampMicroseconds());
}
}
return handle;
}
uint64_t TracingController::AddTraceEventWithTimestamp(
char phase, const uint8_t* category_enabled_flag, const char* name,
const char* scope, uint64_t id, uint64_t bind_id, int num_args,
const char** arg_names, const uint8_t* arg_types,
const uint64_t* arg_values,
std::unique_ptr<v8::ConvertableToTraceFormat>* arg_convertables,
unsigned int flags, int64_t timestamp) {
uint64_t handle = 0;
if (mode_ != DISABLED) {
TraceObject* trace_object = trace_buffer_->AddTraceEvent(&handle);
if (trace_object) {
trace_object->Initialize(phase, category_enabled_flag, name, scope, id,
bind_id, num_args, arg_names, arg_types,
arg_values, arg_convertables, flags, timestamp,
CurrentCpuTimestampMicroseconds());
}
}
return handle;
}
void TracingController::UpdateTraceEventDuration(
const uint8_t* category_enabled_flag, const char* name, uint64_t handle) {
TraceObject* trace_object = trace_buffer_->GetEventByHandle(handle);
if (!trace_object) return;
trace_object->UpdateDuration(CurrentTimestampMicroseconds(),
CurrentCpuTimestampMicroseconds());
}
const uint8_t* TracingController::GetCategoryGroupEnabled(
const char* category_group) {
return GetCategoryGroupEnabledInternal(category_group);
}
const char* TracingController::GetCategoryGroupName(
const uint8_t* category_group_enabled) {
// Calculate the index of the category group by finding
// category_group_enabled in g_category_group_enabled array.
uintptr_t category_begin =
reinterpret_cast<uintptr_t>(g_category_group_enabled);
uintptr_t category_ptr = reinterpret_cast<uintptr_t>(category_group_enabled);
// Check for out of bounds category pointers.
DCHECK(category_ptr >= category_begin &&
category_ptr < reinterpret_cast<uintptr_t>(g_category_group_enabled +
MAX_CATEGORY_GROUPS));
uintptr_t category_index =
(category_ptr - category_begin) / sizeof(g_category_group_enabled[0]);
return g_category_groups[category_index];
}
void TracingController::StartTracing(TraceConfig* trace_config) {
trace_config_.reset(trace_config);
std::unordered_set<v8::TracingController::TraceStateObserver*> observers_copy;
{
base::LockGuard<base::Mutex> lock(mutex_.get());
mode_ = RECORDING_MODE;
UpdateCategoryGroupEnabledFlags();
observers_copy = observers_;
}
for (auto o : observers_copy) {
o->OnTraceEnabled();
}
}
void TracingController::StopTracing() {
if (mode_ == DISABLED) {
return;
}
DCHECK(trace_buffer_);
mode_ = DISABLED;
UpdateCategoryGroupEnabledFlags();
std::unordered_set<v8::TracingController::TraceStateObserver*> observers_copy;
{
base::LockGuard<base::Mutex> lock(mutex_.get());
observers_copy = observers_;
}
for (auto o : observers_copy) {
o->OnTraceDisabled();
}
trace_buffer_->Flush();
}
void TracingController::UpdateCategoryGroupEnabledFlag(size_t category_index) {
unsigned char enabled_flag = 0;
const char* category_group = g_category_groups[category_index];
if (mode_ == RECORDING_MODE &&
trace_config_->IsCategoryGroupEnabled(category_group)) {
enabled_flag |= ENABLED_FOR_RECORDING;
}
// TODO(fmeawad): EventCallback and ETW modes are not yet supported in V8.
// TODO(primiano): this is a temporary workaround for catapult:#2341,
// to guarantee that metadata events are always added even if the category
// filter is "-*". See crbug.com/618054 for more details and long-term fix.
if (mode_ == RECORDING_MODE && !strcmp(category_group, "__metadata")) {
enabled_flag |= ENABLED_FOR_RECORDING;
}
base::Relaxed_Store(reinterpret_cast<base::Atomic8*>(
g_category_group_enabled + category_index),
enabled_flag);
}
void TracingController::UpdateCategoryGroupEnabledFlags() {
size_t category_index = base::Relaxed_Load(&g_category_index);
for (size_t i = 0; i < category_index; i++) UpdateCategoryGroupEnabledFlag(i);
}
const uint8_t* TracingController::GetCategoryGroupEnabledInternal(
const char* category_group) {
// Check that category groups does not contain double quote
DCHECK(!strchr(category_group, '"'));
// The g_category_groups is append only, avoid using a lock for the fast path.
size_t category_index = base::Acquire_Load(&g_category_index);
// Search for pre-existing category group.
for (size_t i = 0; i < category_index; ++i) {
if (strcmp(g_category_groups[i], category_group) == 0) {
return &g_category_group_enabled[i];
}
}
// Slow path. Grab the lock.
base::LockGuard<base::Mutex> lock(mutex_.get());
// Check the list again with lock in hand.
unsigned char* category_group_enabled = nullptr;
category_index = base::Acquire_Load(&g_category_index);
for (size_t i = 0; i < category_index; ++i) {
if (strcmp(g_category_groups[i], category_group) == 0) {
return &g_category_group_enabled[i];
}
}
// Create a new category group.
// Check that there is a slot for the new category_group.
DCHECK(category_index < MAX_CATEGORY_GROUPS);
if (category_index < MAX_CATEGORY_GROUPS) {
// Don't hold on to the category_group pointer, so that we can create
// category groups with strings not known at compile time (this is
// required by SetWatchEvent).
const char* new_group = strdup(category_group);
g_category_groups[category_index] = new_group;
DCHECK(!g_category_group_enabled[category_index]);
// Note that if both included and excluded patterns in the
// TraceConfig are empty, we exclude nothing,
// thereby enabling this category group.
UpdateCategoryGroupEnabledFlag(category_index);
category_group_enabled = &g_category_group_enabled[category_index];
// Update the max index now.
base::Release_Store(&g_category_index, category_index + 1);
} else {
category_group_enabled =
&g_category_group_enabled[g_category_categories_exhausted];
}
return category_group_enabled;
}
void TracingController::AddTraceStateObserver(
v8::TracingController::TraceStateObserver* observer) {
{
base::LockGuard<base::Mutex> lock(mutex_.get());
observers_.insert(observer);
if (mode_ != RECORDING_MODE) return;
}
// Fire the observer if recording is already in progress.
observer->OnTraceEnabled();
}
void TracingController::RemoveTraceStateObserver(
v8::TracingController::TraceStateObserver* observer) {
base::LockGuard<base::Mutex> lock(mutex_.get());
DCHECK(observers_.find(observer) != observers_.end());
observers_.erase(observer);
}
} // namespace tracing
} // namespace platform
} // namespace v8
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