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go/misc
Russ Cox 01f05d8ff1 runtime: unify asmcgocall and systemstack traceback setup
Both asmcgocall and systemstack need to save the calling Go code's
context for use by traceback, but they do it differently.
Systemstack's appraoch is better, because it doesn't require a
special case in traceback.
So make them both use that.

While we are here, the fake mstart caller in systemstack is
no longer needed and can be removed.
(traceback knows to stop in systemstack because of the writes to SP.)

Also remove the fake mstarts in sys_windows_*.s.

And while we are there, fix the control flow guard code in sys_windows_arm.s.
The current code is using pointers to a stack frame that technically is gone
once we hit the RET instruction. Clearly it's working OK, but better not to depend
on data below SP being preserved, even for just a few instructions.
Store the value we need in other registers instead.
(This code is only used for pushing a sigpanic call, which does not
actually return to the site of the fault and therefore doesn't need to
preserve any of the registers.)

This CL is part of a stack adding windows/arm64
support (#36439), intended to land in the Go 1.17 cycle.
This CL is, however, not windows/arm64-specific.
It is cleanup meant to make the port (and future ports) easier.

Change-Id: Id1e3ef5e54f7ad786e4b87043f2626eba7c3bbd9
Reviewed-on: https://go-review.googlesource.com/c/go/+/288799
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2021-02-19 00:02:06 +00:00
..
android misc/android: fix a typo in README 2019-05-17 06:01:17 +00:00
arm
cgo runtime: unify asmcgocall and systemstack traceback setup 2021-02-19 00:02:06 +00:00
chrome/gophertool misc/chrome/gophertool: replace deprecated tabs.getSelected method 2019-11-18 18:14:37 +00:00
ios misc/ios: fix wording for command line instructions 2020-12-29 21:49:26 +00:00
linkcheck
reboot misc: remove use of relative directories in overlayDir functions 2019-11-25 16:26:15 +00:00
swig
trace cmd/trace: update to use WebComponents V0 polyfill 2020-02-20 19:12:11 +00:00
wasm misc/wasm: check type of argument to Go.run 2020-11-02 13:02:40 +00:00
editors
go.mod misc: add go.mod file 2019-02-27 17:47:31 +00:00