You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
Theodosius/dependencies/asmjit/core/zone.h

650 lines
21 KiB

// AsmJit - Machine code generation for C++
//
// * Official AsmJit Home Page: https://asmjit.com
// * Official Github Repository: https://github.com/asmjit/asmjit
//
// Copyright (c) 2008-2020 The AsmJit Authors
//
// This software is provided 'as-is', without any express or implied
// warranty. In no event will the authors be held liable for any damages
// arising from the use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it
// freely, subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented; you must not
// claim that you wrote the original software. If you use this software
// in a product, an acknowledgment in the product documentation would be
// appreciated but is not required.
// 2. Altered source versions must be plainly marked as such, and must not be
// misrepresented as being the original software.
// 3. This notice may not be removed or altered from any source distribution.
#ifndef ASMJIT_CORE_ZONE_H_INCLUDED
#define ASMJIT_CORE_ZONE_H_INCLUDED
#include "../core/support.h"
ASMJIT_BEGIN_NAMESPACE
//! \addtogroup asmjit_zone
//! \{
// ============================================================================
// [asmjit::Zone]
// ============================================================================
//! Zone memory.
//!
//! Zone is an incremental memory allocator that allocates memory by simply
//! incrementing a pointer. It allocates blocks of memory by using C's `malloc()`,
//! but divides these blocks into smaller segments requested by calling
//! `Zone::alloc()` and friends.
//!
//! Zone has no function to release the allocated memory. It has to be released
//! all at once by calling `reset()`. If you need a more friendly allocator that
//! also supports `release()`, consider using `Zone` with `ZoneAllocator`.
class Zone {
public:
ASMJIT_NONCOPYABLE(Zone)
//! \cond INTERNAL
//! A single block of memory managed by `Zone`.
struct Block {
inline uint8_t* data() const noexcept {
return const_cast<uint8_t*>(reinterpret_cast<const uint8_t*>(this) + sizeof(*this));
}
//! Link to the previous block.
Block* prev;
//! Link to the next block.
Block* next;
//! Size of the block.
size_t size;
};
enum Limits : size_t {
kBlockSize = sizeof(Block),
kBlockOverhead = Globals::kAllocOverhead + kBlockSize,
kMinBlockSize = 64, // The number is ridiculously small, but still possible.
kMaxBlockSize = size_t(1) << (sizeof(size_t) * 8 - 4 - 1),
kMinAlignment = 1,
kMaxAlignment = 64
};
//! Pointer in the current block.
uint8_t* _ptr;
//! End of the current block.
uint8_t* _end;
//! Current block.
Block* _block;
union {
struct {
//! Default block size.
size_t _blockSize : Support::bitSizeOf<size_t>() - 4;
//! First block is temporary (ZoneTmp).
size_t _isTemporary : 1;
//! Block alignment (1 << alignment).
size_t _blockAlignmentShift : 3;
};
size_t _packedData;
};
static ASMJIT_API const Block _zeroBlock;
//! \endcond
//! \name Construction & Destruction
//! \{
//! Creates a new Zone.
//!
//! The `blockSize` parameter describes the default size of the block. If the
//! `size` parameter passed to `alloc()` is greater than the default size
//! `Zone` will allocate and use a larger block, but it will not change the
//! default `blockSize`.
//!
//! It's not required, but it's good practice to set `blockSize` to a
//! reasonable value that depends on the usage of `Zone`. Greater block sizes
//! are generally safer and perform better than unreasonably low block sizes.
ASMJIT_INLINE explicit Zone(size_t blockSize, size_t blockAlignment = 1) noexcept {
_init(blockSize, blockAlignment, nullptr);
}
ASMJIT_INLINE Zone(size_t blockSize, size_t blockAlignment, const Support::Temporary& temporary) noexcept {
_init(blockSize, blockAlignment, &temporary);
}
//! Moves an existing `Zone`.
//!
//! \note You cannot move an existing `ZoneTmp` as it uses embedded storage.
//! Attempting to move `ZoneTmp` would result in assertion failure in debug
//! mode and undefined behavior in release mode.
ASMJIT_INLINE Zone(Zone&& other) noexcept
: _ptr(other._ptr),
_end(other._end),
_block(other._block),
_packedData(other._packedData) {
ASMJIT_ASSERT(!other.isTemporary());
other._block = const_cast<Block*>(&_zeroBlock);
other._ptr = other._block->data();
other._end = other._block->data();
}
//! Destroys the `Zone` instance.
//!
//! This will destroy the `Zone` instance and release all blocks of memory
//! allocated by it. It performs implicit `reset(Globals::kResetHard)`.
ASMJIT_INLINE ~Zone() noexcept { reset(Globals::kResetHard); }
ASMJIT_API void _init(size_t blockSize, size_t blockAlignment, const Support::Temporary* temporary) noexcept;
//! Resets the `Zone` invalidating all blocks allocated.
//!
//! See `Globals::ResetPolicy` for more details.
ASMJIT_API void reset(uint32_t resetPolicy = Globals::kResetSoft) noexcept;
//! \}
//! \name Accessors
//! \{
//! Tests whether this `Zone` is actually a `ZoneTmp` that uses temporary memory.
ASMJIT_INLINE bool isTemporary() const noexcept { return _isTemporary != 0; }
//! Returns the default block size.
ASMJIT_INLINE size_t blockSize() const noexcept { return _blockSize; }
//! Returns the default block alignment.
ASMJIT_INLINE size_t blockAlignment() const noexcept { return size_t(1) << _blockAlignmentShift; }
//! Returns remaining size of the current block.
ASMJIT_INLINE size_t remainingSize() const noexcept { return (size_t)(_end - _ptr); }
//! Returns the current zone cursor (dangerous).
//!
//! This is a function that can be used to get exclusive access to the current
//! block's memory buffer.
template<typename T = uint8_t>
ASMJIT_INLINE T* ptr() noexcept { return reinterpret_cast<T*>(_ptr); }
//! Returns the end of the current zone block, only useful if you use `ptr()`.
template<typename T = uint8_t>
ASMJIT_INLINE T* end() noexcept { return reinterpret_cast<T*>(_end); }
//! Sets the current zone pointer to `ptr` (must be within the current block).
template<typename T>
ASMJIT_INLINE void setPtr(T* ptr) noexcept {
uint8_t* p = reinterpret_cast<uint8_t*>(ptr);
ASMJIT_ASSERT(p >= _ptr && p <= _end);
_ptr = p;
}
//! Sets the end zone pointer to `end` (must be within the current block).
template<typename T>
ASMJIT_INLINE void setEnd(T* end) noexcept {
uint8_t* p = reinterpret_cast<uint8_t*>(end);
ASMJIT_ASSERT(p >= _ptr && p <= _end);
_end = p;
}
//! \}
//! \name Utilities
//! \{
ASMJIT_INLINE void swap(Zone& other) noexcept {
// This could lead to a disaster.
ASMJIT_ASSERT(!this->isTemporary());
ASMJIT_ASSERT(!other.isTemporary());
std::swap(_ptr, other._ptr);
std::swap(_end, other._end);
std::swap(_block, other._block);
std::swap(_packedData, other._packedData);
}
//! Aligns the current pointer to `alignment`.
ASMJIT_INLINE void align(size_t alignment) noexcept {
_ptr = Support::min(Support::alignUp(_ptr, alignment), _end);
}
//! Ensures the remaining size is at least equal or greater than `size`.
//!
//! \note This function doesn't respect any alignment. If you need to ensure
//! there is enough room for an aligned allocation you need to call `align()`
//! before calling `ensure()`.
ASMJIT_INLINE Error ensure(size_t size) noexcept {
if (size <= remainingSize())
return kErrorOk;
else
return _alloc(0, 1) ? kErrorOk : DebugUtils::errored(kErrorOutOfMemory);
}
ASMJIT_INLINE void _assignBlock(Block* block) noexcept {
size_t alignment = blockAlignment();
_ptr = Support::alignUp(block->data(), alignment);
_end = Support::alignDown(block->data() + block->size, alignment);
_block = block;
}
ASMJIT_INLINE void _assignZeroBlock() noexcept {
Block* block = const_cast<Block*>(&_zeroBlock);
_ptr = block->data();
_end = block->data();
_block = block;
}
//! \}
//! \name Allocation
//! \{
//! Allocates the requested memory specified by `size`.
//!
//! Pointer returned is valid until the `Zone` instance is destroyed or reset
//! by calling `reset()`. If you plan to make an instance of C++ from the
//! given pointer use placement `new` and `delete` operators:
//!
//! ```
//! using namespace asmjit;
//!
//! class Object { ... };
//!
//! // Create Zone with default block size of approximately 65536 bytes.
//! Zone zone(65536 - Zone::kBlockOverhead);
//!
//! // Create your objects using zone object allocating, for example:
//! Object* obj = static_cast<Object*>( zone.alloc(sizeof(Object)) );
//!
//! if (!obj) {
//! // Handle out of memory error.
//! }
//!
//! // Placement `new` and `delete` operators can be used to instantiate it.
//! new(obj) Object();
//!
//! // ... lifetime of your objects ...
//!
//! // To destroy the instance (if required).
//! obj->~Object();
//!
//! // Reset or destroy `Zone`.
//! zone.reset();
//! ```
ASMJIT_INLINE void* alloc(size_t size) noexcept {
if (ASMJIT_UNLIKELY(size > remainingSize()))
return _alloc(size, 1);
uint8_t* ptr = _ptr;
_ptr += size;
return static_cast<void*>(ptr);
}
//! Allocates the requested memory specified by `size` and `alignment`.
ASMJIT_INLINE void* alloc(size_t size, size_t alignment) noexcept {
ASMJIT_ASSERT(Support::isPowerOf2(alignment));
uint8_t* ptr = Support::alignUp(_ptr, alignment);
if (ptr >= _end || size > (size_t)(_end - ptr))
return _alloc(size, alignment);
_ptr = ptr + size;
return static_cast<void*>(ptr);
}
//! Allocates the requested memory specified by `size` without doing any checks.
//!
//! Can only be called if `remainingSize()` returns size at least equal to `size`.
ASMJIT_INLINE void* allocNoCheck(size_t size) noexcept {
ASMJIT_ASSERT(remainingSize() >= size);
uint8_t* ptr = _ptr;
_ptr += size;
return static_cast<void*>(ptr);
}
//! Allocates the requested memory specified by `size` and `alignment` without doing any checks.
//!
//! Performs the same operation as `Zone::allocNoCheck(size)` with `alignment` applied.
ASMJIT_INLINE void* allocNoCheck(size_t size, size_t alignment) noexcept {
ASMJIT_ASSERT(Support::isPowerOf2(alignment));
uint8_t* ptr = Support::alignUp(_ptr, alignment);
ASMJIT_ASSERT(size <= (size_t)(_end - ptr));
_ptr = ptr + size;
return static_cast<void*>(ptr);
}
//! Allocates `size` bytes of zeroed memory. See `alloc()` for more details.
ASMJIT_API void* allocZeroed(size_t size, size_t alignment = 1) noexcept;
//! Like `alloc()`, but the return pointer is casted to `T*`.
template<typename T>
ASMJIT_INLINE T* allocT(size_t size = sizeof(T), size_t alignment = alignof(T)) noexcept {
return static_cast<T*>(alloc(size, alignment));
}
//! Like `allocNoCheck()`, but the return pointer is casted to `T*`.
template<typename T>
ASMJIT_INLINE T* allocNoCheckT(size_t size = sizeof(T), size_t alignment = alignof(T)) noexcept {
return static_cast<T*>(allocNoCheck(size, alignment));
}
//! Like `allocZeroed()`, but the return pointer is casted to `T*`.
template<typename T>
ASMJIT_INLINE T* allocZeroedT(size_t size = sizeof(T), size_t alignment = alignof(T)) noexcept {
return static_cast<T*>(allocZeroed(size, alignment));
}
//! Like `new(std::nothrow) T(...)`, but allocated by `Zone`.
template<typename T>
ASMJIT_INLINE T* newT() noexcept {
void* p = alloc(sizeof(T), alignof(T));
if (ASMJIT_UNLIKELY(!p))
return nullptr;
return new(p) T();
}
//! Like `new(std::nothrow) T(...)`, but allocated by `Zone`.
template<typename T, typename... Args>
ASMJIT_INLINE T* newT(Args&&... args) noexcept {
void* p = alloc(sizeof(T), alignof(T));
if (ASMJIT_UNLIKELY(!p))
return nullptr;
return new(p) T(std::forward<Args>(args)...);
}
//! \cond INTERNAL
//!
//! Internal alloc function used by other inlines.
ASMJIT_API void* _alloc(size_t size, size_t alignment) noexcept;
//! \endcond
//! Helper to duplicate data.
ASMJIT_API void* dup(const void* data, size_t size, bool nullTerminate = false) noexcept;
//! Helper to duplicate data.
ASMJIT_INLINE void* dupAligned(const void* data, size_t size, size_t alignment, bool nullTerminate = false) noexcept {
align(alignment);
return dup(data, size, nullTerminate);
}
//! Helper to duplicate a formatted string, maximum size is 256 bytes.
ASMJIT_API char* sformat(const char* str, ...) noexcept;
//! \}
};
// ============================================================================
// [b2d::ZoneTmp]
// ============================================================================
//! \ref Zone with `N` bytes of a static storage, used for the initial block.
//!
//! Temporary zones are used in cases where it's known that some memory will be
//! required, but in many cases it won't exceed N bytes, so the whole operation
//! can be performed without a dynamic memory allocation.
template<size_t N>
class ZoneTmp : public Zone {
public:
ASMJIT_NONCOPYABLE(ZoneTmp<N>)
//! Temporary storage, embedded after \ref Zone.
struct Storage {
char data[N];
} _storage;
//! Creates a temporary zone. Dynamic block size is specified by `blockSize`.
ASMJIT_INLINE explicit ZoneTmp(size_t blockSize, size_t blockAlignment = 1) noexcept
: Zone(blockSize, blockAlignment, Support::Temporary(_storage.data, N)) {}
};
// ============================================================================
// [asmjit::ZoneAllocator]
// ============================================================================
//! Zone-based memory allocator that uses an existing `Zone` and provides a
//! `release()` functionality on top of it. It uses `Zone` only for chunks
//! that can be pooled, and uses libc `malloc()` for chunks that are large.
//!
//! The advantage of ZoneAllocator is that it can allocate small chunks of memory
//! really fast, and these chunks, when released, will be reused by consecutive
//! calls to `alloc()`. Also, since ZoneAllocator uses `Zone`, you can turn any
//! `Zone` into a `ZoneAllocator`, and use it in your `Pass` when necessary.
//!
//! ZoneAllocator is used by AsmJit containers to make containers having only
//! few elements fast (and lightweight) and to allow them to grow and use
//! dynamic blocks when require more storage.
class ZoneAllocator {
public:
ASMJIT_NONCOPYABLE(ZoneAllocator)
//! \cond INTERNAL
enum {
// In short, we pool chunks of these sizes:
// [32, 64, 96, 128, 192, 256, 320, 384, 448, 512]
//! How many bytes per a low granularity pool (has to be at least 16).
kLoGranularity = 32,
//! Number of slots of a low granularity pool.
kLoCount = 4,
//! Maximum size of a block that can be allocated in a low granularity pool.
kLoMaxSize = kLoGranularity * kLoCount,
//! How many bytes per a high granularity pool.
kHiGranularity = 64,
//! Number of slots of a high granularity pool.
kHiCount = 6,
//! Maximum size of a block that can be allocated in a high granularity pool.
kHiMaxSize = kLoMaxSize + kHiGranularity * kHiCount,
//! Alignment of every pointer returned by `alloc()`.
kBlockAlignment = kLoGranularity
};
//! Single-linked list used to store unused chunks.
struct Slot {
//! Link to a next slot in a single-linked list.
Slot* next;
};
//! A block of memory that has been allocated dynamically and is not part of
//! block-list used by the allocator. This is used to keep track of all these
//! blocks so they can be freed by `reset()` if not freed explicitly.
struct DynamicBlock {
DynamicBlock* prev;
DynamicBlock* next;
};
//! \endcond
//! Zone used to allocate memory that fits into slots.
Zone* _zone;
//! Indexed slots containing released memory.
Slot* _slots[kLoCount + kHiCount];
//! Dynamic blocks for larger allocations (no slots).
DynamicBlock* _dynamicBlocks;
//! \name Construction & Destruction
//! \{
//! Creates a new `ZoneAllocator`.
//!
//! \note To use it, you must first `init()` it.
inline ZoneAllocator() noexcept {
memset(this, 0, sizeof(*this));
}
//! Creates a new `ZoneAllocator` initialized to use `zone`.
inline explicit ZoneAllocator(Zone* zone) noexcept {
memset(this, 0, sizeof(*this));
_zone = zone;
}
//! Destroys the `ZoneAllocator`.
inline ~ZoneAllocator() noexcept { reset(); }
//! Tests whether the `ZoneAllocator` is initialized (i.e. has `Zone`).
inline bool isInitialized() const noexcept { return _zone != nullptr; }
//! Convenience function to initialize the `ZoneAllocator` with `zone`.
//!
//! It's the same as calling `reset(zone)`.
inline void init(Zone* zone) noexcept { reset(zone); }
//! Resets this `ZoneAllocator` and also forget about the current `Zone` which
//! is attached (if any). Reset optionally attaches a new `zone` passed, or
//! keeps the `ZoneAllocator` in an uninitialized state, if `zone` is null.
ASMJIT_API void reset(Zone* zone = nullptr) noexcept;
//! \}
//! \name Accessors
//! \{
//! Returns the assigned `Zone` of this allocator or null if this `ZoneAllocator`
//! is not initialized.
inline Zone* zone() const noexcept { return _zone; }
//! \}
//! \cond
//! \name Internals
//! \{
//! Returns the slot index to be used for `size`. Returns `true` if a valid slot
//! has been written to `slot` and `allocatedSize` has been filled with slot
//! exact size (`allocatedSize` can be equal or slightly greater than `size`).
static ASMJIT_INLINE bool _getSlotIndex(size_t size, uint32_t& slot) noexcept {
ASMJIT_ASSERT(size > 0);
if (size > kHiMaxSize)
return false;
if (size <= kLoMaxSize)
slot = uint32_t((size - 1) / kLoGranularity);
else
slot = uint32_t((size - kLoMaxSize - 1) / kHiGranularity) + kLoCount;
return true;
}
//! \overload
static ASMJIT_INLINE bool _getSlotIndex(size_t size, uint32_t& slot, size_t& allocatedSize) noexcept {
ASMJIT_ASSERT(size > 0);
if (size > kHiMaxSize)
return false;
if (size <= kLoMaxSize) {
slot = uint32_t((size - 1) / kLoGranularity);
allocatedSize = Support::alignUp(size, kLoGranularity);
}
else {
slot = uint32_t((size - kLoMaxSize - 1) / kHiGranularity) + kLoCount;
allocatedSize = Support::alignUp(size, kHiGranularity);
}
return true;
}
//! \}
//! \endcond
//! \name Allocation
//! \{
//! \cond INTERNAL
ASMJIT_API void* _alloc(size_t size, size_t& allocatedSize) noexcept;
ASMJIT_API void* _allocZeroed(size_t size, size_t& allocatedSize) noexcept;
ASMJIT_API void _releaseDynamic(void* p, size_t size) noexcept;
//! \endcond
//! Allocates `size` bytes of memory, ideally from an available pool.
//!
//! \note `size` can't be zero, it will assert in debug mode in such case.
inline void* alloc(size_t size) noexcept {
ASMJIT_ASSERT(isInitialized());
size_t allocatedSize;
return _alloc(size, allocatedSize);
}
//! Like `alloc(size)`, but provides a second argument `allocatedSize` that
//! provides a way to know how big the block returned actually is. This is
//! useful for containers to prevent growing too early.
inline void* alloc(size_t size, size_t& allocatedSize) noexcept {
ASMJIT_ASSERT(isInitialized());
return _alloc(size, allocatedSize);
}
//! Like `alloc()`, but the return pointer is casted to `T*`.
template<typename T>
inline T* allocT(size_t size = sizeof(T)) noexcept {
return static_cast<T*>(alloc(size));
}
//! Like `alloc(size)`, but returns zeroed memory.
inline void* allocZeroed(size_t size) noexcept {
ASMJIT_ASSERT(isInitialized());
size_t allocatedSize;
return _allocZeroed(size, allocatedSize);
}
//! Like `alloc(size, allocatedSize)`, but returns zeroed memory.
inline void* allocZeroed(size_t size, size_t& allocatedSize) noexcept {
ASMJIT_ASSERT(isInitialized());
return _allocZeroed(size, allocatedSize);
}
//! Like `allocZeroed()`, but the return pointer is casted to `T*`.
template<typename T>
inline T* allocZeroedT(size_t size = sizeof(T)) noexcept {
return static_cast<T*>(allocZeroed(size));
}
//! Like `new(std::nothrow) T(...)`, but allocated by `Zone`.
template<typename T>
inline T* newT() noexcept {
void* p = allocT<T>();
if (ASMJIT_UNLIKELY(!p))
return nullptr;
return new(p) T();
}
//! Like `new(std::nothrow) T(...)`, but allocated by `Zone`.
template<typename T, typename... Args>
inline T* newT(Args&&... args) noexcept {
void* p = allocT<T>();
if (ASMJIT_UNLIKELY(!p))
return nullptr;
return new(p) T(std::forward<Args>(args)...);
}
//! Releases the memory previously allocated by `alloc()`. The `size` argument
//! has to be the same as used to call `alloc()` or `allocatedSize` returned
//! by `alloc()`.
inline void release(void* p, size_t size) noexcept {
ASMJIT_ASSERT(isInitialized());
ASMJIT_ASSERT(p != nullptr);
ASMJIT_ASSERT(size != 0);
uint32_t slot;
if (_getSlotIndex(size, slot)) {
static_cast<Slot*>(p)->next = static_cast<Slot*>(_slots[slot]);
_slots[slot] = static_cast<Slot*>(p);
}
else {
_releaseDynamic(p, size);
}
}
//! \}
};
//! \}
ASMJIT_END_NAMESPACE
#endif // ASMJIT_CORE_ZONE_H_INCLUDED