[release-branch.go1.15] cmd/link: recompute heapPos after copyHeap
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.
Updates #42082
Fixes #42948
Change-Id: Icb3e4e1c7bf7d1fd3d76a2e0d7dfcb319c661534
Reviewed-on: https://go-review.googlesource.com/c/go/+/270942
Run-TryBot: Carlos Amedee <carlos@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Trust: Cherry Zhang <cherryyz@google.com>
diff --git a/src/cmd/link/internal/ld/outbuf.go b/src/cmd/link/internal/ld/outbuf.go
index 09162ae..7bc8954 100644
--- a/src/cmd/link/internal/ld/outbuf.go
+++ b/src/cmd/link/internal/ld/outbuf.go
@@ -187,7 +187,9 @@
// See if our heap would grow to be too large, and if so, copy it to the end
// of the mmapped area.
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)...)
}
