// Copyright (c) 2014 Google Inc.
//
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
// This header file defines implementation details of how the trace macros in
// SkTraceEventCommon.h collect and store trace events. Anything not
// implementation-specific should go in SkTraceEventCommon.h instead of here.
#ifndef SkTraceEvent_DEFINED
#define SkTraceEvent_DEFINED
#include "SkEventTracer.h"
#include "SkTraceEventCommon.h"
#include <atomic>
////////////////////////////////////////////////////////////////////////////////
// Implementation specific tracing API definitions.
// Makes it easier to add traces with a simple TRACE_EVENT0("skia", TRACE_FUNC).
#if defined(_MSC_VER)
#define TRACE_FUNC __FUNCSIG__
#else
#define TRACE_FUNC __PRETTY_FUNCTION__
#endif
// By default, const char* argument 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) \
skia::tracing_internals::TraceStringWithCopy(str)
#define INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE() \
*INTERNAL_TRACE_EVENT_UID(category_group_enabled) & \
(SkEventTracer::kEnabledForRecording_CategoryGroupEnabledFlags | \
SkEventTracer::kEnabledForEventCallback_CategoryGroupEnabledFlags)
// 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 \
SkEventTracer::GetInstance()->getCategoryGroupEnabled
// Add a trace event to the platform tracing system.
// SkEventTracer::Handle TRACE_EVENT_API_ADD_TRACE_EVENT(
// char phase,
// const uint8_t* category_group_enabled,
// const char* name,
// uint64_t id,
// int num_args,
// const char** arg_names,
// const uint8_t* arg_types,
// const uint64_t* arg_values,
// unsigned char flags)
#define TRACE_EVENT_API_ADD_TRACE_EVENT \
SkEventTracer::GetInstance()->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,
// SkEventTracer::Handle id)
#define TRACE_EVENT_API_UPDATE_TRACE_EVENT_DURATION \
SkEventTracer::GetInstance()->updateTraceEventDuration
// Defines visibility for classes in trace_event.h
#define TRACE_EVENT_API_CLASS_EXPORT SK_API
// We prepend this string to all category names, so that ALL Skia trace events are
// disabled by default when tracing in Chrome.
#define TRACE_CATEGORY_PREFIX "disabled-by-default-"
////////////////////////////////////////////////////////////////////////////////
// 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).
#define INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO_CUSTOM_VARIABLES( \
category_group, atomic, category_group_enabled) \
category_group_enabled = \
reinterpret_cast<const uint8_t*>(atomic.load(std::memory_order_relaxed)); \
if (!category_group_enabled) { \
category_group_enabled = TRACE_EVENT_API_GET_CATEGORY_GROUP_ENABLED(category_group); \
atomic.store(reinterpret_cast<intptr_t>(category_group_enabled), \
std::memory_order_relaxed); \
}
#define INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(category_group) \
static std::atomic<intptr_t> INTERNAL_TRACE_EVENT_UID(atomic){0}; \
const uint8_t* INTERNAL_TRACE_EVENT_UID(category_group_enabled); \
INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO_CUSTOM_VARIABLES( \
TRACE_CATEGORY_PREFIX 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()) { \
skia::tracing_internals::AddTraceEvent( \
phase, INTERNAL_TRACE_EVENT_UID(category_group_enabled), name, \
skia::tracing_internals::kNoEventId, flags, ##__VA_ARGS__); \
} \
} while (0)
// 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 char trace_event_flags = flags | TRACE_EVENT_FLAG_HAS_ID; \
skia::tracing_internals::TraceID trace_event_trace_id( \
id, &trace_event_flags); \
skia::tracing_internals::AddTraceEvent( \
phase, INTERNAL_TRACE_EVENT_UID(category_group_enabled), \
name, trace_event_trace_id.data(), trace_event_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); \
skia::tracing_internals::ScopedTracer INTERNAL_TRACE_EVENT_UID(tracer); \
do { \
if (INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE()) { \
SkEventTracer::Handle h = skia::tracing_internals::AddTraceEvent( \
TRACE_EVENT_PHASE_COMPLETE, \
INTERNAL_TRACE_EVENT_UID(category_group_enabled), \
name, skia::tracing_internals::kNoEventId, \
TRACE_EVENT_FLAG_NONE, ##__VA_ARGS__); \
INTERNAL_TRACE_EVENT_UID(tracer).Initialize( \
INTERNAL_TRACE_EVENT_UID(category_group_enabled), name, h); \
} \
} while (0)
namespace skia {
namespace tracing_internals {
// Specify these values when the corresponding argument of AddTraceEvent is not
// used.
const int kZeroNumArgs = 0;
const uint64_t kNoEventId = 0;
// 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:
TraceID(const void* id, unsigned char* flags)
: data_(static_cast<uint64_t>(reinterpret_cast<uintptr_t>(id))) {
*flags |= TRACE_EVENT_FLAG_MANGLE_ID;
}
TraceID(uint64_t id, unsigned char* flags)
: data_(id) { (void)flags; }
TraceID(unsigned int id, unsigned char* flags)
: data_(id) { (void)flags; }
TraceID(unsigned short id, unsigned char* flags)
: data_(id) { (void)flags; }
TraceID(unsigned char id, unsigned char* flags)
: data_(id) { (void)flags; }
TraceID(long long id, unsigned char* flags)
: data_(static_cast<uint64_t>(id)) { (void)flags; }
TraceID(long id, unsigned char* flags)
: data_(static_cast<uint64_t>(id)) { (void)flags; }
TraceID(int id, unsigned char* flags)
: data_(static_cast<uint64_t>(id)) { (void)flags; }
TraceID(short id, unsigned char* flags)
: data_(static_cast<uint64_t>(id)) { (void)flags; }
TraceID(signed char id, unsigned char* 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;
long long 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 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 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(unsigned short, TRACE_VALUE_TYPE_UINT)
INTERNAL_DECLARE_SET_TRACE_VALUE_INT(unsigned char, TRACE_VALUE_TYPE_UINT)
INTERNAL_DECLARE_SET_TRACE_VALUE_INT(long long, TRACE_VALUE_TYPE_INT)
INTERNAL_DECLARE_SET_TRACE_VALUE_INT(long, TRACE_VALUE_TYPE_INT)
INTERNAL_DECLARE_SET_TRACE_VALUE_INT(int, TRACE_VALUE_TYPE_INT)
INTERNAL_DECLARE_SET_TRACE_VALUE_INT(short, 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 and AddTraceEvent template
// functions are 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 inline SkEventTracer::Handle
AddTraceEvent(
char phase,
const uint8_t* category_group_enabled,
const char* name,
uint64_t id,
unsigned char flags) {
return TRACE_EVENT_API_ADD_TRACE_EVENT(
phase, category_group_enabled, name, id,
kZeroNumArgs, nullptr, nullptr, nullptr, flags);
}
template<class ARG1_TYPE>
static inline SkEventTracer::Handle
AddTraceEvent(
char phase,
const uint8_t* category_group_enabled,
const char* name,
uint64_t id,
unsigned char 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,
num_args, &arg1_name, arg_types, arg_values, flags);
}
template<class ARG1_TYPE, class ARG2_TYPE>
static inline SkEventTracer::Handle
AddTraceEvent(
char phase,
const uint8_t* category_group_enabled,
const char* name,
uint64_t id,
unsigned char 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,
num_args, arg_names, arg_types, arg_values, flags);
}
// Used by TRACE_EVENTx macros. Do not use directly.
class TRACE_EVENT_API_CLASS_EXPORT ScopedTracer {
public:
// Note: members of data_ intentionally left uninitialized. See Initialize.
ScopedTracer() : p_data_(nullptr) {}
~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,
SkEventTracer::Handle 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;
SkEventTracer::Handle event_handle;
};
Data* p_data_;
Data data_;
};
} // namespace tracing_internals
} // namespace skia
#endif