tree f3353ac6f31405b7a43be51cc018623c70c91aa4
parent 9d062e8ba05951d44602fc97cc55e3cd4084dcc9
author Than McIntosh <thanm@google.com> 1656595877 -0400
committer Copybara-Service <copybara-worker@google.com> 1658844630 -0700

tsan: capture shadow map start/end on init and reuse in reset

Capture the computed shadow begin/end values at the point where the
shadow is first created and reuse those values on reset. Introduce new
windows-specific function "ZeroMmapFixedRegion" for zeroing out an
address space region previously returned by one of the MmapFixed*
routines; call this function (on windows) from DoResetImpl
tsan_rtl.cpp instead of MmapFixedSuperNoReserve.

See https://github.com/golang/go/issues/53539#issuecomment-1168778740
for context; intended to help with updating the syso for Go's
windows/amd64 race detector.

Differential Revision: https://reviews.llvm.org/D128909

GitOrigin-RevId: b6374437af39af66896da74a1dc1b8a0ece26bee