github.com/cloudwego/frugal@v0.1.15/internal/rt/stackmap.go (about)

     1  /*
     2   * Copyright 2022 ByteDance Inc.
     3   *
     4   * Licensed under the Apache License, Version 2.0 (the "License");
     5   * you may not use this file except in compliance with the License.
     6   * You may obtain a copy of the License at
     7   *
     8   *     http://www.apache.org/licenses/LICENSE-2.0
     9   *
    10   * Unless required by applicable law or agreed to in writing, software
    11   * distributed under the License is distributed on an "AS IS" BASIS,
    12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13   * See the License for the specific language governing permissions and
    14   * limitations under the License.
    15   */
    16  
    17  package rt
    18  
    19  import (
    20      `fmt`
    21      `strings`
    22      `sync`
    23      `unsafe`
    24  )
    25  
    26  type Bitmap struct {
    27      N int
    28      B []byte
    29  }
    30  
    31  func (self *Bitmap) grow() {
    32      if self.N >= len(self.B) * 8 {
    33          self.B = append(self.B, 0)
    34      }
    35  }
    36  
    37  func (self *Bitmap) mark(i int, bv int) {
    38      if bv != 0 {
    39          self.B[i / 8] |= 1 << (i % 8)
    40      } else {
    41          self.B[i / 8] &^= 1 << (i % 8)
    42      }
    43  }
    44  
    45  func (self *Bitmap) Set(i int, bv int) {
    46      if i >= self.N {
    47          panic("bitmap: invalid bit position")
    48      } else {
    49          self.mark(i, bv)
    50      }
    51  }
    52  
    53  func (self *Bitmap) Append(bv int) {
    54      self.grow()
    55      self.mark(self.N, bv)
    56      self.N++
    57  }
    58  
    59  func (self *Bitmap) AppendMany(n int, bv int) {
    60      for i := 0; i < n; i++ {
    61          self.Append(bv)
    62      }
    63  }
    64  
    65  var (
    66      _stackMapLock  = sync.Mutex{}
    67      _stackMapCache = make(map[*StackMap]struct{})
    68  )
    69  
    70  type BitVec struct {
    71      N uintptr
    72      B unsafe.Pointer
    73  }
    74  
    75  func (self BitVec) Bit(i uintptr) byte {
    76      return (*(*byte)(unsafe.Pointer(uintptr(self.B) + i / 8)) >> (i % 8)) & 1
    77  }
    78  
    79  func (self BitVec) String() string {
    80      var i uintptr
    81      var v []string
    82  
    83      /* add each bit */
    84      for i = 0; i < self.N; i++ {
    85          v = append(v, fmt.Sprintf("%d", self.Bit(i)))
    86      }
    87  
    88      /* join them together */
    89      return fmt.Sprintf(
    90          "BitVec { %s }",
    91          strings.Join(v, ", "),
    92      )
    93  }
    94  
    95  type StackMap struct {
    96      N int32
    97      L int32
    98      B [1]byte
    99  }
   100  
   101  func (self *StackMap) add() {
   102      _stackMapLock.Lock()
   103      _stackMapCache[self] = struct{}{}
   104      _stackMapLock.Unlock()
   105  }
   106  
   107  func (self *StackMap) Pin() uintptr {
   108      self.add()
   109      return uintptr(unsafe.Pointer(self))
   110  }
   111  
   112  func (self *StackMap) Get(i int32) BitVec {
   113      return BitVec {
   114          N: uintptr(self.L),
   115          B: unsafe.Pointer(uintptr(unsafe.Pointer(&self.B)) + uintptr(i * ((self.L + 7) >> 3))),
   116      }
   117  }
   118  
   119  func (self *StackMap) String() string {
   120      sb := strings.Builder{}
   121      sb.WriteString("StackMap {")
   122  
   123      /* dump every stack map */
   124      for i := int32(0); i < self.N; i++ {
   125          sb.WriteRune('\n')
   126          sb.WriteString("    " + self.Get(i).String())
   127      }
   128  
   129      /* close the stackmap */
   130      sb.WriteString("\n}")
   131      return sb.String()
   132  }
   133  
   134  var (
   135      byteType = UnpackEface(byte(0)).Type
   136  )
   137  
   138  const (
   139      _StackMapSize = unsafe.Sizeof(StackMap{})
   140  )
   141  
   142  //go:linkname mallocgc runtime.mallocgc
   143  //goland:noinspection GoUnusedParameter
   144  func mallocgc(nb uintptr, vt *GoType, zero bool) unsafe.Pointer
   145  
   146  type StackMapBuilder struct {
   147      b Bitmap
   148  }
   149  
   150  func (self *StackMapBuilder) Build() (p *StackMap) {
   151      nb := len(self.b.B)
   152      bm := mallocgc(_StackMapSize + uintptr(nb) - 1, byteType, false)
   153  
   154      /* initialize as 1 bitmap of N bits */
   155      p = (*StackMap)(bm)
   156      p.N, p.L = 1, int32(self.b.N)
   157      copy(BytesFrom(unsafe.Pointer(&p.B), nb, nb), self.b.B)
   158      return
   159  }
   160  
   161  func (self *StackMapBuilder) AddField(ptr bool) {
   162      if ptr {
   163          self.b.Append(1)
   164      } else {
   165          self.b.Append(0)
   166      }
   167  }
   168  
   169  func (self *StackMapBuilder) AddFields(n int, ptr bool) {
   170      if ptr {
   171          self.b.AppendMany(n, 1)
   172      } else {
   173          self.b.AppendMany(n, 0)
   174      }
   175  }