gtsocial-umbx

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backend.go (2613B)

      1 /*
      2  * Copyright 2021 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 jit
     18 
     19 import (
     20     `fmt`
     21     `sync`
     22     _ `unsafe`
     23 
     24     `github.com/twitchyliquid64/golang-asm/asm/arch`
     25     `github.com/twitchyliquid64/golang-asm/obj`
     26     `github.com/twitchyliquid64/golang-asm/objabi`
     27 )
     28 
     29 type Backend struct {
     30     Ctxt *obj.Link
     31     Arch *arch.Arch
     32     Head *obj.Prog
     33     Tail *obj.Prog
     34     Prog []*obj.Prog
     35 }
     36 
     37 var (
     38     _progPool sync.Pool
     39 )
     40 
     41 //go:nosplit
     42 //go:linkname throw runtime.throw
     43 func throw(_ string)
     44 
     45 func newProg() *obj.Prog {
     46     if val := _progPool.Get(); val == nil {
     47         return new(obj.Prog)
     48     } else {
     49         return remProg(val.(*obj.Prog))
     50     }
     51 }
     52 
     53 func remProg(p *obj.Prog) *obj.Prog {
     54     *p = obj.Prog{}
     55     return p
     56 }
     57 
     58 func newBackend(name string) (ret *Backend) {
     59     ret      = new(Backend)
     60     ret.Arch = arch.Set(name)
     61     ret.Ctxt = newLinkContext(ret.Arch.LinkArch)
     62     ret.Arch.Init(ret.Ctxt)
     63     return
     64 }
     65 
     66 func newLinkContext(arch *obj.LinkArch) (ret *obj.Link) {
     67     ret          = obj.Linknew(arch)
     68     ret.Headtype = objabi.Hlinux
     69     ret.DiagFunc = diagLinkContext
     70     return
     71 }
     72 
     73 func diagLinkContext(str string, args ...interface{}) {
     74     throw(fmt.Sprintf(str, args...))
     75 }
     76 
     77 func (self *Backend) New() (ret *obj.Prog) {
     78     ret = newProg()
     79     ret.Ctxt = self.Ctxt
     80     self.Prog = append(self.Prog, ret)
     81     return
     82 }
     83 
     84 func (self *Backend) Append(p *obj.Prog) {
     85     if self.Head == nil {
     86         self.Head = p
     87         self.Tail = p
     88     } else {
     89         self.Tail.Link = p
     90         self.Tail = p
     91     }
     92 }
     93 
     94 func (self *Backend) Release() {
     95     self.Arch = nil
     96     self.Ctxt = nil
     97 
     98     /* return all the progs into pool */
     99     for _, p := range self.Prog {
    100         _progPool.Put(p)
    101     }
    102 
    103     /* clear all the references */
    104     self.Head = nil
    105     self.Tail = nil
    106     self.Prog = nil
    107 }
    108 
    109 func (self *Backend) Assemble() []byte {
    110     var sym obj.LSym
    111     var fnv obj.FuncInfo
    112 
    113     /* construct the function */
    114     sym.Func = &fnv
    115     fnv.Text = self.Head
    116 
    117     /* call the assembler */
    118     self.Arch.Assemble(self.Ctxt, &sym, self.New)
    119     return sym.P
    120 }