// Copyright 2015 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.
#ifndef SRC_TRACING_TRACE_EVENT_H_
#define SRC_TRACING_TRACE_EVENT_H_
#include <stddef.h>
#include "base/trace_event/common/trace_event_common.h"
#include "include/v8-platform.h"
#include "src/base/atomicops.h"
// This header file defines implementation details of how the trace macros in
// trace_event_common.h collect and store trace events. Anything not
// implementation-specific should go in trace_macros_common.h instead of here.
// The pointer returned from GetCategoryGroupEnabled() points to a
// value with zero or more of the following bits. Used in this class only.
// The TRACE_EVENT macros should only use the value as a bool.
// These values must be in sync with macro values in trace_log.h in
// chromium.
enum CategoryGroupEnabledFlags {
// Category group enabled for the recording mode.
kEnabledForRecording_CategoryGroupEnabledFlags = 1 << 0,
// Category group enabled for the monitoring mode.
kEnabledForMonitoring_CategoryGroupEnabledFlags = 1 << 1,
// Category group enabled by SetEventCallbackEnabled().
kEnabledForEventCallback_CategoryGroupEnabledFlags = 1 << 2,
// Category group enabled to export events to ETW.
kEnabledForETWExport_CategoryGroupEnabledFlags = 1 << 3,
};
// By default, const char* asrgument values are assumed to have long-lived scope
// and will not be copied. Use this macro to force a const char* to be copied.
#define TRACE_STR_COPY(str) v8::internal::tracing::TraceStringWithCopy(str)
// By default, uint64 ID argument values are not mangled with the Process ID in
// TRACE_EVENT_ASYNC macros. Use this macro to force Process ID mangling.
#define TRACE_ID_MANGLE(id) v8::internal::tracing::TraceID::ForceMangle(id)
// By default, pointers are mangled with the Process ID in TRACE_EVENT_ASYNC
// macros. Use this macro to prevent Process ID mangling.
#define TRACE_ID_DONT_MANGLE(id) v8::internal::tracing::TraceID::DontMangle(id)
// Sets the current sample state to the given category and name (both must be
// constant strings). These states are intended for a sampling profiler.
// Implementation note: we store category and name together because we don't
// want the inconsistency/expense of storing two pointers.
// |thread_bucket| is [0..2] and is used to statically isolate samples in one
// thread from others.
#define TRACE_EVENT_SET_SAMPLING_STATE_FOR_BUCKET(bucket_number, category, \
name) \
v8::internal::tracing::TraceEventSamplingStateScope<bucket_number>::Set( \
category "\0" name)
// Returns a current sampling state of the given bucket.
#define TRACE_EVENT_GET_SAMPLING_STATE_FOR_BUCKET(bucket_number) \
v8::internal::tracing::TraceEventSamplingStateScope<bucket_number>::Current()
// Creates a scope of a sampling state of the given bucket.
//
// { // The sampling state is set within this scope.
// TRACE_EVENT_SAMPLING_STATE_SCOPE_FOR_BUCKET(0, "category", "name");
// ...;
// }
#define TRACE_EVENT_SCOPED_SAMPLING_STATE_FOR_BUCKET(bucket_number, category, \
name) \
v8::internal::TraceEventSamplingStateScope<bucket_number> \
traceEventSamplingScope(category "\0" name);
#define INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE() \
*INTERNAL_TRACE_EVENT_UID(category_group_enabled) & \
(kEnabledForRecording_CategoryGroupEnabledFlags | \
kEnabledForEventCallback_CategoryGroupEnabledFlags)
// The following macro has no implementation, but it needs to exist since
// it gets called from scoped trace events. It cannot call UNIMPLEMENTED()
// since an empty implementation is a valid one.
#define INTERNAL_TRACE_MEMORY(category, name)
////////////////////////////////////////////////////////////////////////////////
// Implementation specific tracing API definitions.
// Get a pointer to the enabled state of the given trace category. Only
// long-lived literal strings should be given as the category group. The
// returned pointer can be held permanently in a local static for example. If
// the unsigned char is non-zero, tracing is enabled. If tracing is enabled,
// TRACE_EVENT_API_ADD_TRACE_EVENT can be called. It's OK if tracing is disabled
// between the load of the tracing state and the call to
// TRACE_EVENT_API_ADD_TRACE_EVENT, because this flag only provides an early out
// for best performance when tracing is disabled.
// const uint8_t*
// TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED(const char* category_group)
#define TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED \
v8::internal::tracing::TraceEventHelper::GetCurrentPlatform() \
->GetCategoryGroupEnabled
// Get the number of times traces have been recorded. This is used to implement
// the TRACE_EVENT_IS_NEW_TRACE facility.
// unsigned int TRACE_EVENT_API_GET_NUM_TRACES_RECORDED()
#define TRACE_EVENT_API_GET_NUM_TRACES_RECORDED \
v8::internal::tracing::TraceEventHelper::GetCurrentPlatform() \
->getNumTracesRecorded
// Add a trace event to the platform tracing system.
// uint64_t TRACE_EVENT_API_ADD_TRACE_EVENT(
// char phase,
// const uint8_t* category_group_enabled,
// const char* name,
// uint64_t id,
// uint64_t bind_id,
// int num_args,
// const char** arg_names,
// const uint8_t* arg_types,
// const uint64_t* arg_values,
// unsigned int flags)
#define TRACE_EVENT_API_ADD_TRACE_EVENT \
v8::internal::tracing::TraceEventHelper::GetCurrentPlatform()->AddTraceEvent
// Set the duration field of a COMPLETE trace event.
// void TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION(
// const uint8_t* category_group_enabled,
// const char* name,
// uint64_t id)
#define TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION \
v8::internal::tracing::TraceEventHelper::GetCurrentPlatform() \
->UpdateTraceEventDuration
// Defines atomic operations used internally by the tracing system.
#define TRACE_EVENT_API_ATOMIC_WORD v8::base::AtomicWord
#define TRACE_EVENT_API_ATOMIC_LOAD(var) v8::base::NoBarrier_Load(&(var))
#define TRACE_EVENT_API_ATOMIC_STORE(var, value) \
v8::base::NoBarrier_Store(&(var), (value))
// The thread buckets for the sampling profiler.
extern TRACE_EVENT_API_ATOMIC_WORD g_trace_state[3];
#define TRACE_EVENT_API_THREAD_BUCKET(thread_bucket) \
g_trace_state[thread_bucket]
////////////////////////////////////////////////////////////////////////////////
// Implementation detail: trace event macros create temporary variables
// to keep instrumentation overhead low. These macros give each temporary
// variable a unique name based on the line number to prevent name collisions.
#define INTERNAL_TRACE_EVENT_UID3(a, b) trace_event_unique_##a##b
#define INTERNAL_TRACE_EVENT_UID2(a, b) INTERNAL_TRACE_EVENT_UID3(a, b)
#define INTERNAL_TRACE_EVENT_UID(name_prefix) \
INTERNAL_TRACE_EVENT_UID2(name_prefix, __LINE__)
// Implementation detail: internal macro to create static category.
// No barriers are needed, because this code is designed to operate safely
// even when the unsigned char* points to garbage data (which may be the case
// on processors without cache coherency).
// TODO(fmeawad): This implementation contradicts that we can have a different
// configuration for each isolate,
// https://code.google.com/p/v8/issues/detail?id=4563
#define INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO_CUSTOM_VARIABLES( \
category_group, atomic, category_group_enabled) \
category_group_enabled = \
reinterpret_cast<const uint8_t*>(TRACE_EVENT_API_ATOMIC_LOAD(atomic)); \
if (!category_group_enabled) { \
category_group_enabled = \
TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED(category_group); \
TRACE_EVENT_API_ATOMIC_STORE( \
atomic, reinterpret_cast<TRACE_EVENT_API_ATOMIC_WORD>( \
category_group_enabled)); \
}
#define INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category_group) \
static TRACE_EVENT_API_ATOMIC_WORD INTERNAL_TRACE_EVENT_UID(atomic) = 0; \
const uint8_t* INTERNAL_TRACE_EVENT_UID(category_group_enabled); \
INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO_CUSTOM_VARIABLES( \
category_group, INTERNAL_TRACE_EVENT_UID(atomic), \
INTERNAL_TRACE_EVENT_UID(category_group_enabled));
// Implementation detail: internal macro to create static category and add
// event if the category is enabled.
#define INTERNAL_TRACE_EVENT_ADD(phase, category_group, name, flags, ...) \
do { \
INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category_group); \
if (INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE()) { \
v8::internal::tracing::AddTraceEvent( \
phase, INTERNAL_TRACE_EVENT_UID(category_group_enabled), name, \
v8::internal::tracing::kNoId, v8::internal::tracing::kNoId, flags, \
##__VA_ARGS__); \
} \
} while (0)
// Implementation detail: internal macro to create static category and add begin
// event if the category is enabled. Also adds the end event when the scope
// ends.
#define INTERNAL_TRACE_EVENT_ADD_SCOPED(category_group, name, ...) \
INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category_group); \
v8::internal::tracing::ScopedTracer INTERNAL_TRACE_EVENT_UID(tracer); \
if (INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE()) { \
uint64_t h = v8::internal::tracing::AddTraceEvent( \
TRACE_EVENT_PHASE_COMPLETE, \
INTERNAL_TRACE_EVENT_UID(category_group_enabled), name, \
v8::internal::tracing::kNoId, v8::internal::tracing::kNoId, \
TRACE_EVENT_FLAG_NONE, ##__VA_ARGS__); \
INTERNAL_TRACE_EVENT_UID(tracer) \
.Initialize(INTERNAL_TRACE_EVENT_UID(category_group_enabled), name, \
h); \
}
#define INTERNAL_TRACE_EVENT_ADD_SCOPED_WITH_FLOW(category_group, name, \
bind_id, flow_flags, ...) \
INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category_group); \
v8::internal::tracing::ScopedTracer INTERNAL_TRACE_EVENT_UID(tracer); \
if (INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE()) { \
unsigned int trace_event_flags = flow_flags; \
v8::internal::tracing::TraceID trace_event_bind_id(bind_id, \
&trace_event_flags); \
uint64_t h = v8::internal::tracing::AddTraceEvent( \
TRACE_EVENT_PHASE_COMPLETE, \
INTERNAL_TRACE_EVENT_UID(category_group_enabled), name, \
v8::internal::tracing::kNoId, trace_event_bind_id.data(), \
trace_event_flags, ##__VA_ARGS__); \
INTERNAL_TRACE_EVENT_UID(tracer) \
.Initialize(INTERNAL_TRACE_EVENT_UID(category_group_enabled), name, \
h); \
}
// Implementation detail: internal macro to create static category and add
// event if the category is enabled.
#define INTERNAL_TRACE_EVENT_ADD_WITH_ID(phase, category_group, name, id, \
flags, ...) \
do { \
INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category_group); \
if (INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE()) { \
unsigned int trace_event_flags = flags | TRACE_EVENT_FLAG_HAS_ID; \
v8::internal::tracing::TraceID trace_event_trace_id(id, \
&trace_event_flags); \
v8::internal::tracing::AddTraceEvent( \
phase, INTERNAL_TRACE_EVENT_UID(category_group_enabled), name, \
trace_event_trace_id.data(), v8::internal::tracing::kNoId, \
trace_event_flags, ##__VA_ARGS__); \
} \
} while (0)
// Adds a trace event with a given timestamp. Not Implemented.
#define INTERNAL_TRACE_EVENT_ADD_WITH_TIMESTAMP(phase, category_group, name, \
timestamp, flags, ...) \
UNIMPLEMENTED()
// Adds a trace event with a given id and timestamp. Not Implemented.
#define INTERNAL_TRACE_EVENT_ADD_WITH_ID_AND_TIMESTAMP( \
phase, category_group, name, id, timestamp, flags, ...) \
UNIMPLEMENTED()
// Adds a trace event with a given id, thread_id, and timestamp. Not
// Implemented.
#define INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP( \
phase, category_group, name, id, thread_id, timestamp, flags, ...) \
UNIMPLEMENTED()
namespace v8 {
namespace internal {
namespace tracing {
// Specify these values when the corresponding argument of AddTraceEvent is not
// used.
const int kZeroNumArgs = 0;
const uint64_t kNoId = 0;
class TraceEventHelper {
public:
static v8::Platform* GetCurrentPlatform();
};
// TraceID encapsulates an ID that can either be an integer or pointer. Pointers
// are by default mangled with the Process ID so that they are unlikely to
// collide when the same pointer is used on different processes.
class TraceID {
public:
class DontMangle {
public:
explicit DontMangle(const void* id)
: data_(static_cast<uint64_t>(reinterpret_cast<uintptr_t>(id))) {}
explicit DontMangle(uint64_t id) : data_(id) {}
explicit DontMangle(unsigned int id) : data_(id) {}
explicit DontMangle(uint16_t id) : data_(id) {}
explicit DontMangle(unsigned char id) : data_(id) {}
explicit DontMangle(int64_t id) : data_(static_cast<uint64_t>(id)) {}
explicit DontMangle(int id) : data_(static_cast<uint64_t>(id)) {}
explicit DontMangle(int16_t id) : data_(static_cast<uint64_t>(id)) {}
explicit DontMangle(signed char id) : data_(static_cast<uint64_t>(id)) {}
uint64_t data() const { return data_; }
private:
uint64_t data_;
};
class ForceMangle {
public:
explicit ForceMangle(uint64_t id) : data_(id) {}
explicit ForceMangle(unsigned int id) : data_(id) {}
explicit ForceMangle(uint16_t id) : data_(id) {}
explicit ForceMangle(unsigned char id) : data_(id) {}
explicit ForceMangle(int64_t id) : data_(static_cast<uint64_t>(id)) {}
explicit ForceMangle(int id) : data_(static_cast<uint64_t>(id)) {}
explicit ForceMangle(int16_t id) : data_(static_cast<uint64_t>(id)) {}
explicit ForceMangle(signed char id) : data_(static_cast<uint64_t>(id)) {}
uint64_t data() const { return data_; }
private:
uint64_t data_;
};
TraceID(const void* id, unsigned int* flags)
: data_(static_cast<uint64_t>(reinterpret_cast<uintptr_t>(id))) {
*flags |= TRACE_EVENT_FLAG_MANGLE_ID;
}
TraceID(ForceMangle id, unsigned int* flags) : data_(id.data()) {
*flags |= TRACE_EVENT_FLAG_MANGLE_ID;
}
TraceID(DontMangle id, unsigned int* flags) : data_(id.data()) {}
TraceID(uint64_t id, unsigned int* flags) : data_(id) { (void)flags; }
TraceID(unsigned int id, unsigned int* flags) : data_(id) { (void)flags; }
TraceID(uint16_t id, unsigned int* flags) : data_(id) { (void)flags; }
TraceID(unsigned char id, unsigned int* flags) : data_(id) { (void)flags; }
TraceID(int64_t id, unsigned int* flags) : data_(static_cast<uint64_t>(id)) {
(void)flags;
}
TraceID(int id, unsigned int* flags) : data_(static_cast<uint64_t>(id)) {
(void)flags;
}
TraceID(int16_t id, unsigned int* flags) : data_(static_cast<uint64_t>(id)) {
(void)flags;
}
TraceID(signed char id, unsigned int* flags)
: data_(static_cast<uint64_t>(id)) {
(void)flags;
}
uint64_t data() const { return data_; }
private:
uint64_t data_;
};
// Simple union to store various types as uint64_t.
union TraceValueUnion {
bool as_bool;
uint64_t as_uint;
int64_t as_int;
double as_double;
const void* as_pointer;
const char* as_string;
};
// Simple container for const char* that should be copied instead of retained.
class TraceStringWithCopy {
public:
explicit TraceStringWithCopy(const char* str) : str_(str) {}
operator const char*() const { return str_; }
private:
const char* str_;
};
// Define SetTraceValue for each allowed type. It stores the type and
// value in the return arguments. This allows this API to avoid declaring any
// structures so that it is portable to third_party libraries.
#define INTERNAL_DECLARE_SET_TRACE_VALUE(actual_type, union_member, \
value_type_id) \
static V8_INLINE void SetTraceValue(actual_type arg, unsigned char* type, \
uint64_t* value) { \
TraceValueUnion type_value; \
type_value.union_member = arg; \
*type = value_type_id; \
*value = type_value.as_uint; \
}
// Simpler form for int types that can be safely casted.
#define INTERNAL_DECLARE_SET_TRACE_VALUE_INT(actual_type, value_type_id) \
static V8_INLINE void SetTraceValue(actual_type arg, unsigned char* type, \
uint64_t* value) { \
*type = value_type_id; \
*value = static_cast<uint64_t>(arg); \
}
INTERNAL_DECLARE_SET_TRACE_VALUE_INT(uint64_t, TRACE_VALUE_TYPE_UINT)
INTERNAL_DECLARE_SET_TRACE_VALUE_INT(unsigned int, TRACE_VALUE_TYPE_UINT)
INTERNAL_DECLARE_SET_TRACE_VALUE_INT(uint16_t, TRACE_VALUE_TYPE_UINT)
INTERNAL_DECLARE_SET_TRACE_VALUE_INT(unsigned char, TRACE_VALUE_TYPE_UINT)
INTERNAL_DECLARE_SET_TRACE_VALUE_INT(int64_t, TRACE_VALUE_TYPE_INT)
INTERNAL_DECLARE_SET_TRACE_VALUE_INT(int, TRACE_VALUE_TYPE_INT)
INTERNAL_DECLARE_SET_TRACE_VALUE_INT(int16_t, TRACE_VALUE_TYPE_INT)
INTERNAL_DECLARE_SET_TRACE_VALUE_INT(signed char, TRACE_VALUE_TYPE_INT)
INTERNAL_DECLARE_SET_TRACE_VALUE(bool, as_bool, TRACE_VALUE_TYPE_BOOL)
INTERNAL_DECLARE_SET_TRACE_VALUE(double, as_double, TRACE_VALUE_TYPE_DOUBLE)
INTERNAL_DECLARE_SET_TRACE_VALUE(const void*, as_pointer,
TRACE_VALUE_TYPE_POINTER)
INTERNAL_DECLARE_SET_TRACE_VALUE(const char*, as_string,
TRACE_VALUE_TYPE_STRING)
INTERNAL_DECLARE_SET_TRACE_VALUE(const TraceStringWithCopy&, as_string,
TRACE_VALUE_TYPE_COPY_STRING)
#undef INTERNAL_DECLARE_SET_TRACE_VALUE
#undef INTERNAL_DECLARE_SET_TRACE_VALUE_INT
// These AddTraceEvent template
// function is defined here instead of in the macro, because the arg_values
// could be temporary objects, such as std::string. In order to store
// pointers to the internal c_str and pass through to the tracing API,
// the arg_values must live throughout these procedures.
static V8_INLINE uint64_t AddTraceEvent(char phase,
const uint8_t* category_group_enabled,
const char* name, uint64_t id,
uint64_t bind_id, unsigned int flags) {
return TRACE_EVENT_API_ADD_TRACE_EVENT(phase, category_group_enabled, name,
id, bind_id, kZeroNumArgs, NULL, NULL,
NULL, flags);
}
template <class ARG1_TYPE>
static V8_INLINE uint64_t AddTraceEvent(char phase,
const uint8_t* category_group_enabled,
const char* name, uint64_t id,
uint64_t bind_id, unsigned int flags,
const char* arg1_name,
const ARG1_TYPE& arg1_val) {
const int num_args = 1;
uint8_t arg_types[1];
uint64_t arg_values[1];
SetTraceValue(arg1_val, &arg_types[0], &arg_values[0]);
return TRACE_EVENT_API_ADD_TRACE_EVENT(phase, category_group_enabled, name,
id, bind_id, num_args, &arg1_name,
arg_types, arg_values, flags);
}
template <class ARG1_TYPE, class ARG2_TYPE>
static V8_INLINE uint64_t AddTraceEvent(
char phase, const uint8_t* category_group_enabled, const char* name,
uint64_t id, uint64_t bind_id, unsigned int flags, const char* arg1_name,
const ARG1_TYPE& arg1_val, const char* arg2_name,
const ARG2_TYPE& arg2_val) {
const int num_args = 2;
const char* arg_names[2] = {arg1_name, arg2_name};
unsigned char arg_types[2];
uint64_t arg_values[2];
SetTraceValue(arg1_val, &arg_types[0], &arg_values[0]);
SetTraceValue(arg2_val, &arg_types[1], &arg_values[1]);
return TRACE_EVENT_API_ADD_TRACE_EVENT(phase, category_group_enabled, name,
id, bind_id, num_args, arg_names,
arg_types, arg_values, flags);
}
// Used by TRACE_EVENTx macros. Do not use directly.
class ScopedTracer {
public:
// Note: members of data_ intentionally left uninitialized. See Initialize.
ScopedTracer() : p_data_(NULL) {}
~ScopedTracer() {
if (p_data_ && *data_.category_group_enabled)
TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION(
data_.category_group_enabled, data_.name, data_.event_handle);
}
void Initialize(const uint8_t* category_group_enabled, const char* name,
uint64_t event_handle) {
data_.category_group_enabled = category_group_enabled;
data_.name = name;
data_.event_handle = event_handle;
p_data_ = &data_;
}
private:
// This Data struct workaround is to avoid initializing all the members
// in Data during construction of this object, since this object is always
// constructed, even when tracing is disabled. If the members of Data were
// members of this class instead, compiler warnings occur about potential
// uninitialized accesses.
struct Data {
const uint8_t* category_group_enabled;
const char* name;
uint64_t event_handle;
};
Data* p_data_;
Data data_;
};
// Used by TRACE_EVENT_BINARY_EFFICIENTx macro. Do not use directly.
class ScopedTraceBinaryEfficient {
public:
ScopedTraceBinaryEfficient(const char* category_group, const char* name);
~ScopedTraceBinaryEfficient();
private:
const uint8_t* category_group_enabled_;
const char* name_;
uint64_t event_handle_;
};
// TraceEventSamplingStateScope records the current sampling state
// and sets a new sampling state. When the scope exists, it restores
// the sampling state having recorded.
template <size_t BucketNumber>
class TraceEventSamplingStateScope {
public:
explicit TraceEventSamplingStateScope(const char* category_and_name) {
previous_state_ = TraceEventSamplingStateScope<BucketNumber>::Current();
TraceEventSamplingStateScope<BucketNumber>::Set(category_and_name);
}
~TraceEventSamplingStateScope() {
TraceEventSamplingStateScope<BucketNumber>::Set(previous_state_);
}
static V8_INLINE const char* Current() {
return reinterpret_cast<const char*>(
TRACE_EVENT_API_ATOMIC_LOAD(g_trace_state[BucketNumber]));
}
static V8_INLINE void Set(const char* category_and_name) {
TRACE_EVENT_API_ATOMIC_STORE(g_trace_state[BucketNumber],
reinterpret_cast<TRACE_EVENT_API_ATOMIC_WORD>(
const_cast<char*>(category_and_name)));
}
private:
const char* previous_state_;
};
} // namespace tracing
} // namespace internal
} // namespace v8
#endif // SRC_TRACING_TRACE_EVENT_H_