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cmd/link: recompute heapPos after copyHeap

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Immediately after a forward Seek, the offset we're writing to is
beyond len(buf)+len(heap):

|<--- buf --->|<--- heap --->|
                                    ^
                                    off

If we do a copyHeap at this point, the new heapPos should not be
0:

|<---------- buf ----------->|<-heap->|
                                    ^
                                    off

Recompute it.

For #42082.

Change-Id: Icb3e4e1c7bf7d1fd3d76a2e0d7dfcb319c661534
Reviewed-on: https://go-review.googlesource.com/c/go/+/270941
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
This commit is contained in:
Cherry Zhang 2020-11-17 19:10:51 -05:00
parent 64ef84881f
commit b194b5151f
1 changed files with 3 additions and 1 deletions
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4
src/cmd/link/internal/ld/outbuf.go
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@ -183,7 +183,9 @@ func (out *OutBuf) writeLoc(lenToWrite int64) (int64, []byte) {
// See if our heap would grow to be too large, and if so, copy it to the end // See if our heap would grow to be too large, and if so, copy it to the end
// of the mmapped area. // of the mmapped area.
if heapLen > maxOutBufHeapLen && out.copyHeap() { if heapLen > maxOutBufHeapLen && out.copyHeap() {
heapPos, heapLen, lenNeeded = 0, 0, lenToWrite heapPos -= heapLen
lenNeeded = heapPos + lenToWrite
heapLen = 0
} }
out.heap = append(out.heap, make([]byte, lenNeeded-heapLen)...) out.heap = append(out.heap, make([]byte, lenNeeded-heapLen)...)
} }