runtime: rename _m_ to mp [generated]

_g_, _p_, and _m_ are primarily vestiges of the C version of the
runtime, while today we prefer Go-style variable names (generally gp,
pp, and mp).

This change replaces all remaining uses of _m_ with mp. There are very
few remaining and all replacements are trivial.

[git-generate]
cd src/runtime

rf 'mv canpanic._m_ canpanic.mp'
GOOS=solaris \
  rf 'mv semasleep._m_ semasleep.mp'
GOOS=aix GOARCH=ppc64 \
  rf 'mv semasleep._m_ semasleep.mp'

Change-Id: I83690f7b4d4dc57557963100e9a2560ff343f3e8
Reviewed-on: https://go-review.googlesource.com/c/go/+/307813
Trust: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
diff --git a/src/runtime/os3_solaris.go b/src/runtime/os3_solaris.go
index 3149d13..2e94665 100644
--- a/src/runtime/os3_solaris.go
+++ b/src/runtime/os3_solaris.go
@@ -329,20 +329,20 @@
 
 //go:nosplit
 func semasleep(ns int64) int32 {
-	_m_ := getg().m
+	mp := getg().m
 	if ns >= 0 {
-		_m_.ts.tv_sec = ns / 1000000000
-		_m_.ts.tv_nsec = ns % 1000000000
+		mp.ts.tv_sec = ns / 1000000000
+		mp.ts.tv_nsec = ns % 1000000000
 
-		_m_.libcall.fn = uintptr(unsafe.Pointer(&libc_sem_reltimedwait_np))
-		_m_.libcall.n = 2
-		_m_.scratch = mscratch{}
-		_m_.scratch.v[0] = _m_.waitsema
-		_m_.scratch.v[1] = uintptr(unsafe.Pointer(&_m_.ts))
-		_m_.libcall.args = uintptr(unsafe.Pointer(&_m_.scratch))
-		asmcgocall(unsafe.Pointer(&asmsysvicall6x), unsafe.Pointer(&_m_.libcall))
-		if *_m_.perrno != 0 {
-			if *_m_.perrno == _ETIMEDOUT || *_m_.perrno == _EAGAIN || *_m_.perrno == _EINTR {
+		mp.libcall.fn = uintptr(unsafe.Pointer(&libc_sem_reltimedwait_np))
+		mp.libcall.n = 2
+		mp.scratch = mscratch{}
+		mp.scratch.v[0] = mp.waitsema
+		mp.scratch.v[1] = uintptr(unsafe.Pointer(&mp.ts))
+		mp.libcall.args = uintptr(unsafe.Pointer(&mp.scratch))
+		asmcgocall(unsafe.Pointer(&asmsysvicall6x), unsafe.Pointer(&mp.libcall))
+		if *mp.perrno != 0 {
+			if *mp.perrno == _ETIMEDOUT || *mp.perrno == _EAGAIN || *mp.perrno == _EINTR {
 				return -1
 			}
 			throw("sem_reltimedwait_np")
@@ -350,16 +350,16 @@
 		return 0
 	}
 	for {
-		_m_.libcall.fn = uintptr(unsafe.Pointer(&libc_sem_wait))
-		_m_.libcall.n = 1
-		_m_.scratch = mscratch{}
-		_m_.scratch.v[0] = _m_.waitsema
-		_m_.libcall.args = uintptr(unsafe.Pointer(&_m_.scratch))
-		asmcgocall(unsafe.Pointer(&asmsysvicall6x), unsafe.Pointer(&_m_.libcall))
-		if _m_.libcall.r1 == 0 {
+		mp.libcall.fn = uintptr(unsafe.Pointer(&libc_sem_wait))
+		mp.libcall.n = 1
+		mp.scratch = mscratch{}
+		mp.scratch.v[0] = mp.waitsema
+		mp.libcall.args = uintptr(unsafe.Pointer(&mp.scratch))
+		asmcgocall(unsafe.Pointer(&asmsysvicall6x), unsafe.Pointer(&mp.libcall))
+		if mp.libcall.r1 == 0 {
 			break
 		}
-		if *_m_.perrno == _EINTR {
+		if *mp.perrno == _EINTR {
 			continue
 		}
 		throw("sem_wait")
diff --git a/src/runtime/os_aix.go b/src/runtime/os_aix.go
index 54e0cfb..c21da4d 100644
--- a/src/runtime/os_aix.go
+++ b/src/runtime/os_aix.go
@@ -49,7 +49,7 @@
 
 //go:nosplit
 func semasleep(ns int64) int32 {
-	_m_ := getg().m
+	mp := getg().m
 	if ns >= 0 {
 		var ts timespec
 
@@ -63,17 +63,17 @@
 			ts.tv_nsec -= 1e9
 		}
 
-		if r, err := sem_timedwait((*semt)(unsafe.Pointer(_m_.waitsema)), &ts); r != 0 {
+		if r, err := sem_timedwait((*semt)(unsafe.Pointer(mp.waitsema)), &ts); r != 0 {
 			if err == _ETIMEDOUT || err == _EAGAIN || err == _EINTR {
 				return -1
 			}
-			println("sem_timedwait err ", err, " ts.tv_sec ", ts.tv_sec, " ts.tv_nsec ", ts.tv_nsec, " ns ", ns, " id ", _m_.id)
+			println("sem_timedwait err ", err, " ts.tv_sec ", ts.tv_sec, " ts.tv_nsec ", ts.tv_nsec, " ns ", ns, " id ", mp.id)
 			throw("sem_timedwait")
 		}
 		return 0
 	}
 	for {
-		r1, err := sem_wait((*semt)(unsafe.Pointer(_m_.waitsema)))
+		r1, err := sem_wait((*semt)(unsafe.Pointer(mp.waitsema)))
 		if r1 == 0 {
 			break
 		}
diff --git a/src/runtime/panic.go b/src/runtime/panic.go
index 94289871..c4f3f41 100644
--- a/src/runtime/panic.go
+++ b/src/runtime/panic.go
@@ -1190,22 +1190,22 @@
 	// Note also that g->m can change at preemption, so m can go stale
 	// if this function ever makes a function call.
 	_g_ := getg()
-	_m_ := _g_.m
+	mp := _g_.m
 
 	// Is it okay for gp to panic instead of crashing the program?
 	// Yes, as long as it is running Go code, not runtime code,
 	// and not stuck in a system call.
-	if gp == nil || gp != _m_.curg {
+	if gp == nil || gp != mp.curg {
 		return false
 	}
-	if _m_.locks != 0 || _m_.mallocing != 0 || _m_.throwing != 0 || _m_.preemptoff != "" || _m_.dying != 0 {
+	if mp.locks != 0 || mp.mallocing != 0 || mp.throwing != 0 || mp.preemptoff != "" || mp.dying != 0 {
 		return false
 	}
 	status := readgstatus(gp)
 	if status&^_Gscan != _Grunning || gp.syscallsp != 0 {
 		return false
 	}
-	if GOOS == "windows" && _m_.libcallsp != 0 {
+	if GOOS == "windows" && mp.libcallsp != 0 {
 		return false
 	}
 	return true