Commit fdde7ba2 authored by Bryan C. Mills's avatar Bryan C. Mills Committed by Ian Lance Taylor

runtime: avoid clobbering C callee-save register in cgoSigtramp

Use R11 (a caller-saved temp register) instead of RBX (a callee-saved
register).

I believe this only affects linux/amd64, since it is the only platform
with a non-trivial cgoSigtramp implementation.

Updates #18328.

Change-Id: I3d35c4512624184d5a8ece653fa09ddf50e079a2
Reviewed-on: https://go-review.googlesource.com/35068Reviewed-by: 's avatarIan Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
parent f65abf6d
......@@ -330,9 +330,9 @@ sigtrampnog:
// Lock sigprofCallersUse.
MOVL $0, AX
MOVL $1, CX
MOVQ $runtime·sigprofCallersUse(SB), BX
MOVQ $runtime·sigprofCallersUse(SB), R11
LOCK
CMPXCHGL CX, 0(BX)
CMPXCHGL CX, 0(R11)
JNZ sigtramp // Skip stack trace if already locked.
// Jump to the traceback function in runtime/cgo.
......
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