rsc.io/go@v0.0.0-20150416155037-e040fd465409/src/runtime/race.go (about)

     1  // Copyright 2012 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  // +build race
     6  
     7  // Public race detection API, present iff build with -race.
     8  
     9  package runtime
    10  
    11  import (
    12  	"unsafe"
    13  )
    14  
    15  func RaceRead(addr unsafe.Pointer)
    16  func RaceWrite(addr unsafe.Pointer)
    17  func RaceReadRange(addr unsafe.Pointer, len int)
    18  func RaceWriteRange(addr unsafe.Pointer, len int)
    19  
    20  func RaceSemacquire(s *uint32)
    21  func RaceSemrelease(s *uint32)
    22  
    23  // private interface for the runtime
    24  const raceenabled = true
    25  
    26  // For all functions accepting callerpc and pc,
    27  // callerpc is a return PC of the function that calls this function,
    28  // pc is start PC of the function that calls this function.
    29  func raceReadObjectPC(t *_type, addr unsafe.Pointer, callerpc, pc uintptr) {
    30  	kind := t.kind & kindMask
    31  	if kind == kindArray || kind == kindStruct {
    32  		// for composite objects we have to read every address
    33  		// because a write might happen to any subobject.
    34  		racereadrangepc(addr, t.size, callerpc, pc)
    35  	} else {
    36  		// for non-composite objects we can read just the start
    37  		// address, as any write must write the first byte.
    38  		racereadpc(addr, callerpc, pc)
    39  	}
    40  }
    41  
    42  func raceWriteObjectPC(t *_type, addr unsafe.Pointer, callerpc, pc uintptr) {
    43  	kind := t.kind & kindMask
    44  	if kind == kindArray || kind == kindStruct {
    45  		// for composite objects we have to write every address
    46  		// because a write might happen to any subobject.
    47  		racewriterangepc(addr, t.size, callerpc, pc)
    48  	} else {
    49  		// for non-composite objects we can write just the start
    50  		// address, as any write must write the first byte.
    51  		racewritepc(addr, callerpc, pc)
    52  	}
    53  }
    54  
    55  //go:noescape
    56  func racereadpc(addr unsafe.Pointer, callpc, pc uintptr)
    57  
    58  //go:noescape
    59  func racewritepc(addr unsafe.Pointer, callpc, pc uintptr)
    60  
    61  type symbolizeContext struct {
    62  	pc   uintptr
    63  	fn   *byte
    64  	file *byte
    65  	line uintptr
    66  	off  uintptr
    67  	res  uintptr
    68  }
    69  
    70  var qq = [...]byte{'?', '?', 0}
    71  var dash = [...]byte{'-', 0}
    72  
    73  // Callback from C into Go, runs on g0.
    74  func racesymbolize(ctx *symbolizeContext) {
    75  	f := findfunc(ctx.pc)
    76  	if f == nil {
    77  		ctx.fn = &qq[0]
    78  		ctx.file = &dash[0]
    79  		ctx.line = 0
    80  		ctx.off = ctx.pc
    81  		ctx.res = 1
    82  		return
    83  	}
    84  
    85  	ctx.fn = cfuncname(f)
    86  	file, line := funcline(f, ctx.pc)
    87  	ctx.line = uintptr(line)
    88  	ctx.file = &bytes(file)[0] // assume NUL-terminated
    89  	ctx.off = ctx.pc - f.entry
    90  	ctx.res = 1
    91  	return
    92  }