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runtime: shade stack-to-stack copy when starting a goroutine

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The hybrid barrier requires barriers on stack-to-stack copies if
either stack is grey. There are only two instances of this in the
runtime: channel sends and starting a goroutine. Channel sends already
use typedmemmove and hence have the necessary barriers. This commits
adds barriers for the stack-to-stack copy when starting a goroutine.

Updates #17503.

Change-Id: Ibb55e08127ca4d021ac54be61cb96732efa5df5b
Reviewed-on: https://go-review.googlesource.com/31455
Reviewed-by: Rick Hudson <rlh@golang.org>
This commit is contained in:
Austin Clements 2016-10-13 15:34:56 -04:00
parent 0c0960a234
commit ee785f03a2
1 changed files with 14 additions and 1 deletions
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15
src/runtime/proc.go
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@ -2810,7 +2810,20 @@ func newproc1(fn *funcval, argp *uint8, narg int32, nret int32, callerpc uintptr
prepGoExitFrame(sp)
spArg += sys.MinFrameSize
}
memmove(unsafe.Pointer(spArg), unsafe.Pointer(argp), uintptr(narg))
if narg > 0 {
memmove(unsafe.Pointer(spArg), unsafe.Pointer(argp), uintptr(narg))
// This is a stack-to-stack copy. If write barriers
// are enabled and the source stack is grey (the
// destination is always black), then perform a
// barrier copy.
if writeBarrier.needed && !_g_.m.curg.gcscandone {
f := findfunc(fn.fn)
stkmap := (*stackmap)(funcdata(f, _FUNCDATA_ArgsPointerMaps))
// We're in the prologue, so it's always stack map index 0.
bv := stackmapdata(stkmap, 0)
bulkBarrierBitmap(spArg, uintptr(narg), 0, bv.bytedata)
}
}
memclrNoHeapPointers(unsafe.Pointer(&newg.sched), unsafe.Sizeof(newg.sched))
newg.sched.sp = sp