github.com/bytedance/mockey@v1.2.10/internal/tool/check_gcflags_amd64.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 tool
    18  
    19  import (
    20  	"reflect"
    21  	"unsafe"
    22  
    23  	"golang.org/x/arch/x86/x86asm"
    24  )
    25  
    26  func fn() {
    27  }
    28  
    29  func fn2() {
    30  	fn()
    31  }
    32  
    33  func IsGCFlagsSet() bool {
    34  	var asm []byte
    35  	header := (*reflect.SliceHeader)(unsafe.Pointer(&asm))
    36  	header.Data = reflect.ValueOf(fn2).Pointer()
    37  	header.Len = 1000
    38  	header.Cap = 1000
    39  
    40  	flag := false
    41  	pos := 0
    42  	for pos < len(asm) {
    43  		inst, _ := x86asm.Decode(asm[pos:], 64)
    44  		if inst.Op == x86asm.RET {
    45  			break
    46  		}
    47  		if inst.Op == x86asm.CALL {
    48  			flag = true
    49  			break
    50  		}
    51  		pos += int(inst.Len)
    52  	}
    53  	return flag
    54  }