counters_supported.go

     1  // Copyright 2021 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build (darwin || linux || windows || freebsd) && (amd64 || arm64)
     6  
     7  package fuzz
     8  
     9  import (
    10  	"internal/unsafeheader"
    11  	"unsafe"
    12  )
    13  
    14  // coverage returns a []byte containing unique 8-bit counters for each edge of
    15  // the instrumented source code. This coverage data will only be generated if
    16  // `-d=libfuzzer` is set at build time. This can be used to understand the code
    17  // coverage of a test execution.
    18  func coverage() []byte {
    19  	addr := unsafe.Pointer(&_counters)
    20  	size := uintptr(unsafe.Pointer(&_ecounters)) - uintptr(addr)
    21  
    22  	var res []byte
    23  	*(*unsafeheader.Slice)(unsafe.Pointer(&res)) = unsafeheader.Slice{
    24  		Data: addr,
    25  		Len:  int(size),
    26  		Cap:  int(size),
    27  	}
    28  	return res
    29  }
    30
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