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mirror of https://github.com/yse/easy_profiler.git synced 2024-12-27 08:41:02 +08:00

Scrapped the alignment macros and replaced them with force-inline template functions; still need to test thoroughly.

This commit is contained in:
rationalcoder 2017-08-19 22:10:51 -05:00
parent 75e4f35abe
commit 283b835dd8

View File

@ -56,6 +56,7 @@ The Apache License, Version 2.0 (the "License");
#include <thread>
#include <atomic>
#include <list>
#include <type_traits>
#include <cstring>
#include <cstddef>
@ -145,50 +146,227 @@ namespace profiler {
# endif
#endif
// Useful on architectures that don't allow unaligned access (e.g. ARMv5).
// If this isn't defined, expressions like: *(uint16_t*)data = 0, will be used
// as usual, which is what you want on something like x86.
#ifdef EASY_ENABLE_STRICT_ALIGNMENT
# define EASY_UA_ZERO16(dst)\
do {\
((char*)dst)[0] = 0;\
((char*)dst)[1] = 0;\
} while(false)
# define EASY_UA_ZERO32(dst)\
do {\
((char*)dst)[0] = 0;\
((char*)dst)[1] = 0;\
((char*)dst)[2] = 0;\
((char*)dst)[3] = 0;\
} while(false)
template <typename T>
struct False : std::false_type {};
// Assumes that unaligned access is more common.
# define EASY_UA_ZERO64(dst)\
do {\
if (((unsigned long)dst & 7) != 0) {\
((char*)dst)[0] = 0;\
((char*)dst)[1] = 0;\
((char*)dst)[2] = 0;\
((char*)dst)[3] = 0;\
((char*)dst)[4] = 0;\
((char*)dst)[5] = 0;\
((char*)dst)[6] = 0;\
((char*)dst)[7] = 0;\
}\
else {\
*(uint64_t*)dst = 0;\
}\
} while(false)
//! Checks if a pointer is aligned.
//! \param ptr The pointer to check.
//! \param alignment The alignement (must be a power of 2)
//! \returns true if the memory is aligned.
//!
template <uint32_t ALIGNMENT>
EASY_FORCE_INLINE bool is_aligned(void* ptr)
{
static_assert(ALIGNMENT % 2 == 0, "Alignment must be a power of two.");
return (uintptr_t)ptr & (ALIGNMENT-1) == 0;
}
# define EASY_UA_SET16(dst, val, type)
# define EASY_UA_SET32(dst, val, type)
# define EASY_UA_SET64(dst, val, type)
# define EASY_UA_LOAD16(dst)
# define EASY_UA_LOAD32(dst)
# define EASY_UA_LOAD64(dst)
EASY_FORCE_INLINE void unaligned_zero16(void* ptr)
{
#ifndef EASY_ENABLE_STRICT_ALIGNMENT
*(uint16_t*)ptr = 0;
#else
((char*)ptr)[0] = 0;
((char*)ptr)[1] = 0;
#endif
}
EASY_FORCE_INLINE void unaligned_zero32(void* ptr)
{
#ifndef EASY_ENABLE_STRICT_ALIGNMENT
*(uint32_t*)ptr = 0;
#else
((char*)ptr)[0] = 0;
((char*)ptr)[1] = 0;
((char*)ptr)[2] = 0;
((char*)ptr)[3] = 0;
#endif
}
EASY_FORCE_INLINE void unaligned_zero64(void* ptr)
{
#ifndef EASY_ENABLE_STRICT_ALIGNMENT
*(uint64_t*)ptr = 0;
#else
// Assume unaligned is more common.
if (!is_aligned<alignof(uint64_t)>(ptr)) {
((char*)ptr)[0] = 0;
((char*)ptr)[1] = 0;
((char*)ptr)[2] = 0;
((char*)ptr)[3] = 0;
((char*)ptr)[4] = 0;
((char*)ptr)[5] = 0;
((char*)ptr)[6] = 0;
((char*)ptr)[7] = 0;
}
else {
*(uint64_t*)ptr = 0;
}
#endif
}
template <typename T>
EASY_FORCE_INLINE void unaligned_store16(void* ptr, T val)
{
static_assert(sizeof(T) == 2, "16 bit type required.");
#ifndef EASY_ENABLE_STRICT_ALIGNMENT
*(T*)ptr = val;
#else
const char* const temp = &val;
((char*)ptr)[0] = temp[0];
((char*)ptr)[1] = temp[1];
#endif
}
template <typename T>
EASY_FORCE_INLINE void unaligned_store32(void* ptr, T val)
{
static_assert(sizeof(T) == 4, "32 bit type required.");
#ifndef EASY_ENABLE_STRICT_ALIGNMENT
*(T*)ptr = val;
#else
const char* const temp = &val;
((char*)ptr)[0] = temp[0];
((char*)ptr)[1] = temp[1];
((char*)ptr)[2] = temp[2];
((char*)ptr)[3] = temp[3];
#endif
}
template <typename T>
EASY_FORCE_INLINE void unaligned_store64(void* ptr, T val)
{
static_assert(sizeof(T) == 8, "64 bit type required.");
#ifndef EASY_ENABLE_STRICT_ALIGNMENT
*(T*)ptr = val;
#else
const char* const temp = &val;
// Assume unaligned is more common.
if (!is_aligned<alignof(T)>(ptr)) {
((char*)ptr)[0] = temp[0];
((char*)ptr)[1] = temp[1];
((char*)ptr)[2] = temp[2];
((char*)ptr)[3] = temp[3];
((char*)ptr)[4] = temp[4];
((char*)ptr)[5] = temp[5];
((char*)ptr)[6] = temp[6];
((char*)ptr)[7] = temp[7];
}
else {
*(T*)ptr = val;
}
#endif
}
template <typename T>
EASY_FORCE_INLINE T unaligned_load16(const void* ptr)
{
static_assert(sizeof(T) == 2, "16 bit type required.");
#ifndef EASY_ENABLE_STRICT_ALIGNMENT
return *(T*)ptr;
#else
T value;
((char*)&value)[0] = ((char*)ptr)[0];
((char*)&value)[1] = ((char*)ptr)[1];
return value;
#endif
}
template <typename T>
EASY_FORCE_INLINE T unaligned_load16(const void* ptr, T* val)
{
static_assert(sizeof(T) == 2, "16 bit type required.");
#ifndef EASY_ENABLE_STRICT_ALIGNMENT
*val = *(T*)ptr;
return *val;
#else
((char*)val)[0] = ((char*)ptr)[0];
((char*)val)[1] = ((char*)ptr)[1];
return *val;
#endif
}
template <typename T>
EASY_FORCE_INLINE T unaligned_load32(const void* ptr)
{
static_assert(sizeof(T) == 4, "32 bit type required.");
#ifndef EASY_ENABLE_STRICT_ALIGNMENT
return *(T*)ptr;
#else
T value;
((char*)&value)[0] = ((char*)ptr)[0];
((char*)&value)[1] = ((char*)ptr)[1];
((char*)&value)[2] = ((char*)ptr)[2];
((char*)&value)[3] = ((char*)ptr)[3];
return value;
#endif
}
template <typename T>
EASY_FORCE_INLINE T unaligned_load32(const void* ptr, T* val)
{
static_assert(sizeof(T) == 4, "32 bit type required.");
#ifndef EASY_ENABLE_STRICT_ALIGNMENT
*val = *(T*)ptr;
#else
((char*)&val)[0] = ((char*)ptr)[0];
((char*)&val)[1] = ((char*)ptr)[1];
((char*)&val)[2] = ((char*)ptr)[2];
((char*)&val)[3] = ((char*)ptr)[3];
return *val;
#endif
}
template <typename T>
EASY_FORCE_INLINE T unaligned_load64(const void* ptr)
{
static_assert(sizeof(T) == 8, "64 bit type required.");
#ifndef EASY_ENABLE_STRICT_ALIGNMENT
return *(T*)ptr;
#else
if (!is_aligned<alignof(T)>(ptr)) {
T value;
((char*)&value)[0] = ((char*)ptr)[0];
((char*)&value)[1] = ((char*)ptr)[1];
((char*)&value)[2] = ((char*)ptr)[2];
((char*)&value)[3] = ((char*)ptr)[3];
((char*)&value)[4] = ((char*)ptr)[4];
((char*)&value)[5] = ((char*)ptr)[5];
((char*)&value)[6] = ((char*)ptr)[6];
((char*)&value)[7] = ((char*)ptr)[7];
return value;
}
else {
return *(T*)ptr;
}
#endif
}
template <typename T>
EASY_FORCE_INLINE T unaligned_load64(const void* ptr, T* val)
{
static_assert(sizeof(T) == 8, "64 bit type required.");
#ifndef EASY_ENABLE_STRICT_ALIGNMENT
*val = *(T*)ptr;
#else
if (!is_aligned<alignof(T)>(ptr)) {
((char*)&val)[0] = ((char*)ptr)[0];
((char*)&val)[1] = ((char*)ptr)[1];
((char*)&val)[2] = ((char*)ptr)[2];
((char*)&val)[3] = ((char*)ptr)[3];
((char*)&val)[4] = ((char*)ptr)[4];
((char*)&val)[5] = ((char*)ptr)[5];
((char*)&val)[6] = ((char*)ptr)[6];
((char*)&val)[7] = ((char*)ptr)[7];
return *val;
}
else {
*val = *(T*)ptr;
return *val;
}
#endif
}
template <uint16_t N>
@ -227,9 +405,9 @@ class chunk_allocator
// Although there is no need for unaligned access stuff b/c a new chunk will
// usually be at least 8 byte aligned (and we only need 2 byte alignment),
// this is the only way I have been able to get rid of the GCC strict-aliasing warning
// without using std::memset.
char* temp = (char*)&last->data[0];
*(uint16_t*)temp = 0;
// without using std::memset. It's an extra line, but is just as fast as *(uint16_t*)last->data = 0;
char* const data = (char*)&last->data;
*(uint16_t*)data = 0;
}
/** Invert current chunks list to enable to iterate over chunks list in direct order.
@ -280,9 +458,14 @@ public:
char* data = (char*)&m_chunks.back().data[0] + chunkOffset;
m_chunkOffset = chunkOffset + n + sizeof(uint16_t);
std::memcpy(data, &n, sizeof(uint16_t));
unaligned_store16(data, n);
data += sizeof(uint16_t);
std::memset(data + n, 0, sizeof(uint16_t));
// If there is enough space for at least another payload size,
// set it to zero.
if (chunkOffset < N-1)
unaligned_zero16(data + n);
return data;
}
@ -293,12 +476,13 @@ public:
char* data = (char*)&m_chunks.back().data[0];
std::memcpy(data, &n, sizeof(uint16_t));
unaligned_store16(data, n);
data += sizeof(uint16_t);
// If there is enough space for at least another payload size,
// set it to zero.
if (chunkOffset < N-1)
std::memset(data + n, 0, sizeof(uint16_t));
unaligned_zero16(data + n);
return data;
}
@ -353,15 +537,12 @@ public:
do {
const char* data = (char*)current->data;
int_fast32_t chunkOffset = 0; // signed int so overflow is not checked.
uint16_t payloadSize = 0;
std::memcpy(&payloadSize, data, sizeof(uint16_t));
while (chunkOffset < MAX_CHUNK_OFFSET && payloadSize != 0) {
uint16_t payloadSize = unaligned_load16<uint16_t>(data);
while (chunkOffset < MAX_CHUNK_OFFSET && unaligned_load16(data, &payloadSize) != 0) {
const uint16_t chunkSize = sizeof(uint16_t) + payloadSize;
_outputStream.write(data, chunkSize);
data += chunkSize;
chunkOffset += chunkSize;
std::memcpy(&payloadSize, data, sizeof(uint16_t));
}
current = current->prev;