| // Copyright 2017, VIXL authors |
| // All rights reserved. |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are met: |
| // |
| // * Redistributions of source code must retain the above copyright notice, |
| // this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above copyright notice, |
| // this list of conditions and the following disclaimer in the documentation |
| // and/or other materials provided with the distribution. |
| // * Neither the name of ARM Limited nor the names of its contributors may be |
| // used to endorse or promote products derived from this software without |
| // specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS CONTRIBUTORS "AS IS" AND |
| // ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
| // WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE |
| // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR |
| // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER |
| // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
| // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| #ifndef VIXL_CODE_BUFFER_H |
| #define VIXL_CODE_BUFFER_H |
| |
| #include <cstring> |
| |
| #include "globals-vixl.h" |
| #include "utils-vixl.h" |
| |
| namespace vixl { |
| |
| class CodeBuffer { |
| public: |
| static const size_t kDefaultCapacity = 4 * KBytes; |
| |
| explicit CodeBuffer(size_t capacity = kDefaultCapacity); |
| CodeBuffer(byte* buffer, size_t capacity); |
| ~CodeBuffer(); |
| |
| void Reset(); |
| |
| #ifdef VIXL_CODE_BUFFER_MMAP |
| void SetExecutable(); |
| void SetWritable(); |
| #else |
| // These require page-aligned memory blocks, which we can only guarantee with |
| // mmap. |
| VIXL_NO_RETURN_IN_DEBUG_MODE void SetExecutable() { VIXL_UNIMPLEMENTED(); } |
| VIXL_NO_RETURN_IN_DEBUG_MODE void SetWritable() { VIXL_UNIMPLEMENTED(); } |
| #endif |
| |
| ptrdiff_t GetOffsetFrom(ptrdiff_t offset) const { |
| ptrdiff_t cursor_offset = cursor_ - buffer_; |
| VIXL_ASSERT((offset >= 0) && (offset <= cursor_offset)); |
| return cursor_offset - offset; |
| } |
| VIXL_DEPRECATED("GetOffsetFrom", |
| ptrdiff_t OffsetFrom(ptrdiff_t offset) const) { |
| return GetOffsetFrom(offset); |
| } |
| |
| ptrdiff_t GetCursorOffset() const { return GetOffsetFrom(0); } |
| VIXL_DEPRECATED("GetCursorOffset", ptrdiff_t CursorOffset() const) { |
| return GetCursorOffset(); |
| } |
| |
| void Rewind(ptrdiff_t offset) { |
| byte* rewound_cursor = buffer_ + offset; |
| VIXL_ASSERT((buffer_ <= rewound_cursor) && (rewound_cursor <= cursor_)); |
| cursor_ = rewound_cursor; |
| } |
| |
| template <typename T> |
| T GetOffsetAddress(ptrdiff_t offset) const { |
| VIXL_STATIC_ASSERT(sizeof(T) >= sizeof(uintptr_t)); |
| VIXL_ASSERT((offset >= 0) && (offset <= (cursor_ - buffer_))); |
| return reinterpret_cast<T>(buffer_ + offset); |
| } |
| |
| // Return the address of the start or end of the buffer. |
| template <typename T> |
| T GetStartAddress() const { |
| VIXL_STATIC_ASSERT(sizeof(T) >= sizeof(uintptr_t)); |
| return GetOffsetAddress<T>(0); |
| } |
| template <typename T> |
| T GetEndAddress() const { |
| VIXL_STATIC_ASSERT(sizeof(T) >= sizeof(uintptr_t)); |
| return GetOffsetAddress<T>(GetCapacity()); |
| } |
| |
| size_t GetRemainingBytes() const { |
| VIXL_ASSERT((cursor_ >= buffer_) && (cursor_ <= (buffer_ + capacity_))); |
| return (buffer_ + capacity_) - cursor_; |
| } |
| VIXL_DEPRECATED("GetRemainingBytes", size_t RemainingBytes() const) { |
| return GetRemainingBytes(); |
| } |
| |
| size_t GetSizeInBytes() const { |
| VIXL_ASSERT((cursor_ >= buffer_) && (cursor_ <= (buffer_ + capacity_))); |
| return cursor_ - buffer_; |
| } |
| |
| // A code buffer can emit: |
| // * 8, 16, 32 or 64-bit data: constant. |
| // * 16 or 32-bit data: instruction. |
| // * string: debug info. |
| void Emit8(uint8_t data) { Emit(data); } |
| |
| void Emit16(uint16_t data) { Emit(data); } |
| |
| void Emit32(uint32_t data) { Emit(data); } |
| |
| void Emit64(uint64_t data) { Emit(data); } |
| |
| void EmitString(const char* string); |
| |
| void EmitData(const void* data, size_t size); |
| |
| template <typename T> |
| void Emit(T value) { |
| VIXL_ASSERT(HasSpaceFor(sizeof(value))); |
| dirty_ = true; |
| memcpy(cursor_, &value, sizeof(value)); |
| cursor_ += sizeof(value); |
| } |
| |
| void UpdateData(size_t offset, const void* data, size_t size); |
| |
| // Align to 32bit. |
| void Align(); |
| |
| // Ensure there is enough space for and emit 'n' zero bytes. |
| void EmitZeroedBytes(int n); |
| |
| bool Is16bitAligned() const { return IsAligned<2>(cursor_); } |
| |
| bool Is32bitAligned() const { return IsAligned<4>(cursor_); } |
| |
| size_t GetCapacity() const { return capacity_; } |
| VIXL_DEPRECATED("GetCapacity", size_t capacity() const) { |
| return GetCapacity(); |
| } |
| |
| bool IsManaged() const { return managed_; } |
| |
| void Grow(size_t new_capacity); |
| |
| bool IsDirty() const { return dirty_; } |
| |
| void SetClean() { dirty_ = false; } |
| |
| bool HasSpaceFor(size_t amount) const { |
| return GetRemainingBytes() >= amount; |
| } |
| |
| void EnsureSpaceFor(size_t amount, bool* has_grown) { |
| bool is_full = !HasSpaceFor(amount); |
| if (is_full) Grow(capacity_ * 2 + amount); |
| VIXL_ASSERT(has_grown != NULL); |
| *has_grown = is_full; |
| } |
| void EnsureSpaceFor(size_t amount) { |
| bool dummy; |
| EnsureSpaceFor(amount, &dummy); |
| } |
| |
| private: |
| // Backing store of the buffer. |
| byte* buffer_; |
| // If true the backing store is allocated and deallocated by the buffer. The |
| // backing store can then grow on demand. If false the backing store is |
| // provided by the user and cannot be resized internally. |
| bool managed_; |
| // Pointer to the next location to be written. |
| byte* cursor_; |
| // True if there has been any write since the buffer was created or cleaned. |
| bool dirty_; |
| // Capacity in bytes of the backing store. |
| size_t capacity_; |
| }; |
| |
| } // namespace vixl |
| |
| #endif // VIXL_CODE_BUFFER_H |