constpool.h

// [AsmJit]
// Complete x86/x64 JIT and Remote Assembler for C++.
//
// [License]
// Zlib - See LICENSE.md file in the package.

// [Guard]
#ifndef _ASMJIT_BASE_CONSTPOOL_H
#define _ASMJIT_BASE_CONSTPOOL_H

// [Dependencies - AsmJit]
#include "../base/error.h"
#include "../base/zone.h"

// [Api-Begin]
#include "../apibegin.h"

namespace asmjit {

//! \addtogroup asmjit_base_util
//! \{

// ============================================================================
// [asmjit::ConstPoolNode]
// ============================================================================

//! \internal
//!
//! Zone-allocated constant-pool node.
struct ConstPoolNode {
  // --------------------------------------------------------------------------
  // [Accessors]
  // --------------------------------------------------------------------------

  ASMJIT_INLINE void* getData() const {
    return static_cast<void*>(const_cast<ConstPoolNode*>(this) + 1);
  }

  // --------------------------------------------------------------------------
  // [Members]
  // --------------------------------------------------------------------------

  //! Left/Right nodes.
  ConstPoolNode* _link[2];
  //! Horizontal level for balance.
  uint32_t _level : 31;
  //! Whether this constant is shared with another.
  uint32_t _shared : 1;
  //! Data offset from the beginning of the pool.
  uint32_t _offset;
};

// ============================================================================
// [asmjit::ConstPoolTree]
// ============================================================================

//! \internal
//!
//! Zone-allocated constant-pool tree.
struct ConstPoolTree {
  enum {
    //! Maximum tree height == log2(1 << 64).
    kHeightLimit = 64
  };

  // --------------------------------------------------------------------------
  // [Construction / Destruction]
  // --------------------------------------------------------------------------

  ASMJIT_INLINE ConstPoolTree(size_t dataSize = 0) :
    _root(NULL),
    _length(0),
    _dataSize(dataSize) {}
  ASMJIT_INLINE ~ConstPoolTree() {}

  // --------------------------------------------------------------------------
  // [Reset]
  // --------------------------------------------------------------------------

  ASMJIT_INLINE void reset() {
    _root = NULL;
    _length = 0;
  }

  // --------------------------------------------------------------------------
  // [Accessors]
  // --------------------------------------------------------------------------

  ASMJIT_INLINE bool isEmpty() const {
    return _length == 0;
  }

  ASMJIT_INLINE size_t getLength() const {
    return _length;
  }

  ASMJIT_INLINE void setDataSize(size_t dataSize) {
    ASMJIT_ASSERT(isEmpty());
    _dataSize = dataSize;
  }

  // --------------------------------------------------------------------------
  // [Ops]
  // --------------------------------------------------------------------------

  ASMJIT_API ConstPoolNode* get(const void* data);
  ASMJIT_API void put(ConstPoolNode* node);

  // --------------------------------------------------------------------------
  // [Iterate]
  // --------------------------------------------------------------------------

  template<typename Visitor>
  ASMJIT_INLINE void iterate(Visitor& visitor) const {
    ConstPoolNode* node = const_cast<ConstPoolNode*>(_root);
    ConstPoolNode* link;

    ConstPoolNode* stack[kHeightLimit];

    if (node == NULL)
      return;

    size_t top = 0;

    for (;;) {
      link = node->_link[0];

      if (link != NULL) {
        ASMJIT_ASSERT(top != kHeightLimit);
        stack[top++] = node;

        node = link;
        continue;
      }

_Visit:
      visitor.visit(node);
      link = node->_link[1];

      if (link != NULL) {
        node = link;
        continue;
      }

      if (top == 0)
        break;

      node = stack[--top];
      goto _Visit;
    }
  }

  // --------------------------------------------------------------------------
  // [Helpers]
  // --------------------------------------------------------------------------

  static ASMJIT_INLINE ConstPoolNode* _newNode(Zone* zone, const void* data, size_t size, size_t offset, bool shared) {
    ConstPoolNode* node = zone->allocT<ConstPoolNode>(sizeof(ConstPoolNode) + size);
    if (node == NULL)
      return NULL;

    node->_link[0] = NULL;
    node->_link[1] = NULL;
    node->_level = 1;
    node->_shared = shared;
    node->_offset = static_cast<uint32_t>(offset);

    ::memcpy(node->getData(), data, size);
    return node;
  }

  // --------------------------------------------------------------------------
  // [Members]
  // --------------------------------------------------------------------------

  //! Root of the tree
  ConstPoolNode* _root;
  //! Length of the tree (count of nodes).
  size_t _length;
  //! Size of the data.
  size_t _dataSize;
};

// ============================================================================
// [asmjit::ConstPoolGap]
// ============================================================================

//! \internal
//!
//! Zone-allocated constant-pool gap.
struct ConstPoolGap {
  //! Link to the next gap
  ConstPoolGap* _next;
  //! Offset of the gap.
  size_t _offset;
  //! Remaining bytes of the gap (basically a gap size).
  size_t _length;
};

// ============================================================================
// [asmjit::ConstPool]
// ============================================================================

//! Constant pool.
struct ConstPool {
  ASMJIT_NO_COPY(ConstPool)

  enum {
    kIndex1 = 0,
    kIndex2 = 1,
    kIndex4 = 2,
    kIndex8 = 3,
    kIndex16 = 4,
    kIndex32 = 5,
    kIndexCount = 6
  };

  // --------------------------------------------------------------------------
  // [Construction / Destruction]
  // --------------------------------------------------------------------------

  ASMJIT_API ConstPool(Zone* zone);
  ASMJIT_API ~ConstPool();

  // --------------------------------------------------------------------------
  // [Reset]
  // --------------------------------------------------------------------------

  ASMJIT_API void reset();

  // --------------------------------------------------------------------------
  // [Ops]
  // --------------------------------------------------------------------------

  //! Get whether the constant-pool is empty.
  ASMJIT_INLINE bool isEmpty() const {
    return _size == 0;
  }

  //! Get the size of the constant-pool in bytes.
  ASMJIT_INLINE size_t getSize() const {
    return _size;
  }

  //! Get minimum alignment.
  ASMJIT_INLINE size_t getAlignment() const {
    return _alignment;
  }

  //! Add a constant to the constant pool.
  //!
  //! The constant must have known size, which is 1, 2, 4, 8, 16 or 32 bytes.
  //! The constant is added to the pool only if it doesn't not exist, otherwise
  //! cached value is returned.
  //!
  //! AsmJit is able to subdivide added constants, so for example if you add
  //! 8-byte constant 0x1122334455667788 it will create the following slots:
  //!
  //!   8-byte: 0x1122334455667788
  //!   4-byte: 0x11223344, 0x55667788
  //!
  //! The reason is that when combining MMX/SSE/AVX code some patterns are used
  //! frequently. However, AsmJit is not able to reallocate a constant that has
  //! been already added. For example if you try to add 4-byte constant and then
  //! 8-byte constant having the same 4-byte pattern as the previous one, two
  //! independent slots will be generated by the pool.
  ASMJIT_API Error add(const void* data, size_t size, size_t& dstOffset);

  // --------------------------------------------------------------------------
  // [Fill]
  // --------------------------------------------------------------------------

  //! Fill the destination with the constants from the pool.
  ASMJIT_API void fill(void* dst);

  // --------------------------------------------------------------------------
  // [Members]
  // --------------------------------------------------------------------------

  //! Zone allocator.
  Zone* _zone;
  //! Tree per size.
  ConstPoolTree _tree[kIndexCount];
  //! Gaps per size.
  ConstPoolGap* _gaps[kIndexCount];
  //! Gaps pool
  ConstPoolGap* _gapPool;

  //! Size of the pool (in bytes).
  size_t _size;
  //! Alignemnt.
  size_t _alignment;
};

//! \}

} // asmjit namespace

// [Api-End]
#include "../apiend.h"

// [Guard]
#endif // _ASMJIT_BASE_CONSTPOOL_H