dep: Add vixl (AArch32/64 assembler)

dep/vixl/include/vixl/code-buffer-vixl.h

@@ -0,0 +1,191 @@
+// 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 emitted code.
+  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>(GetSizeInBytes());
+  }
+
+  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