runtime: tidy _Stack* constant naming

For #59670.

Change-Id: I0efa743edc08e48dc8d906803ba45e9f641369db
Reviewed-on: https://go-review.googlesource.com/c/go/+/486977
Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>

src/runtime/asm_386.s

@@ -186,7 +186,7 @@ nocpuinfo:
 	// update stackguard after _cgo_init
 	MOVL	$runtime·g0(SB), CX
 	MOVL	(g_stack+stack_lo)(CX), AX
-	ADDL	$const__StackGuard, AX
+	ADDL	$const_stackGuard, AX
 	MOVL	AX, g_stackguard0(CX)
 	MOVL	AX, g_stackguard1(CX)
 

src/runtime/asm_amd64.s

@@ -222,7 +222,7 @@ nocpuinfo:
 	// update stackguard after _cgo_init
 	MOVQ	$runtime·g0(SB), CX
 	MOVQ	(g_stack+stack_lo)(CX), AX
-	ADDQ	$const__StackGuard, AX
+	ADDQ	$const_stackGuard, AX
 	MOVQ	AX, g_stackguard0(CX)
 	MOVQ	AX, g_stackguard1(CX)
 

src/runtime/asm_arm.s

@@ -151,7 +151,7 @@ TEXT runtime·rt0_go(SB),NOSPLIT|NOFRAME|TOPFRAME,$0
 
 	// update stackguard after _cgo_init
 	MOVW	(g_stack+stack_lo)(g), R0
-	ADD	$const__StackGuard, R0
+	ADD	$const_stackGuard, R0
 	MOVW	R0, g_stackguard0(g)
 	MOVW	R0, g_stackguard1(g)
 

src/runtime/asm_arm64.s

@@ -59,7 +59,7 @@ nocgo:
 	BL	runtime·save_g(SB)
 	// update stackguard after _cgo_init
 	MOVD	(g_stack+stack_lo)(g), R0
-	ADD	$const__StackGuard, R0
+	ADD	$const_stackGuard, R0
 	MOVD	R0, g_stackguard0(g)
 	MOVD	R0, g_stackguard1(g)
 

src/runtime/asm_loong64.s

@@ -39,7 +39,7 @@ TEXT runtime·rt0_go(SB),NOSPLIT|TOPFRAME,$0
 nocgo:
 	// update stackguard after _cgo_init
 	MOVV	(g_stack+stack_lo)(g), R19
-	ADDV	$const__StackGuard, R19
+	ADDV	$const_stackGuard, R19
 	MOVV	R19, g_stackguard0(g)
 	MOVV	R19, g_stackguard1(g)
 

src/runtime/asm_mips64x.s

@@ -41,7 +41,7 @@ TEXT runtime·rt0_go(SB),NOSPLIT|TOPFRAME,$0
 nocgo:
 	// update stackguard after _cgo_init
 	MOVV	(g_stack+stack_lo)(g), R1
-	ADDV	$const__StackGuard, R1
+	ADDV	$const_stackGuard, R1
 	MOVV	R1, g_stackguard0(g)
 	MOVV	R1, g_stackguard1(g)
 

src/runtime/asm_mipsx.s

@@ -42,7 +42,7 @@ TEXT runtime·rt0_go(SB),NOSPLIT|TOPFRAME,$0
 nocgo:
 	// update stackguard after _cgo_init
 	MOVW	(g_stack+stack_lo)(g), R1
-	ADD	$const__StackGuard, R1
+	ADD	$const_stackGuard, R1
 	MOVW	R1, g_stackguard0(g)
 	MOVW	R1, g_stackguard1(g)
 

src/runtime/asm_ppc64x.s

@@ -67,7 +67,7 @@ TEXT runtime·rt0_go(SB),NOSPLIT|TOPFRAME,$0
 nocgo:
 	// update stackguard after _cgo_init
 	MOVD	(g_stack+stack_lo)(g), R3
-	ADD	$const__StackGuard, R3
+	ADD	$const_stackGuard, R3
 	MOVD	R3, g_stackguard0(g)
 	MOVD	R3, g_stackguard1(g)
 

src/runtime/asm_riscv64.s

@@ -36,7 +36,7 @@ TEXT runtime·rt0_go(SB),NOSPLIT|TOPFRAME,$0
 nocgo:
 	// update stackguard after _cgo_init
 	MOV	(g_stack+stack_lo)(g), T0
-	ADD	$const__StackGuard, T0
+	ADD	$const_stackGuard, T0
 	MOV	T0, g_stackguard0(g)
 	MOV	T0, g_stackguard1(g)
 

src/runtime/asm_s390x.s

@@ -126,7 +126,7 @@ TEXT runtime·rt0_go(SB),NOSPLIT|TOPFRAME,$0
 nocgo:
 	// update stackguard after _cgo_init
 	MOVD	(g_stack+stack_lo)(g), R2
-	ADD	$const__StackGuard, R2
+	ADD	$const_stackGuard, R2
 	MOVD	R2, g_stackguard0(g)
 	MOVD	R2, g_stackguard1(g)
 

src/runtime/os_windows.go

@@ -993,7 +993,7 @@ func minit() {
 		throw("bad g0 stack")
 	}
 	g0.stack.lo = base
-	g0.stackguard0 = g0.stack.lo + _StackGuard
+	g0.stackguard0 = g0.stack.lo + stackGuard
 	g0.stackguard1 = g0.stackguard0
 	// Sanity check the SP.
 	stackcheck()

src/runtime/preempt.go

@@ -172,7 +172,7 @@ func suspendG(gp *g) suspendGState {
 			// _Gscan bit and thus own the stack.
 			gp.preemptStop = false
 			gp.preempt = false
-			gp.stackguard0 = gp.stack.lo + _StackGuard
+			gp.stackguard0 = gp.stack.lo + stackGuard
 
 			// The goroutine was already at a safe-point
 			// and we've now locked that in.

src/runtime/proc.go

@@ -832,7 +832,7 @@ func mcommoninit(mp *m, id int64) {
 
 	mpreinit(mp)
 	if mp.gsignal != nil {
-		mp.gsignal.stackguard1 = mp.gsignal.stack.lo + _StackGuard
+		mp.gsignal.stackguard1 = mp.gsignal.stack.lo + stackGuard
 	}
 
 	// Add to allm so garbage collector doesn't free g->m
@@ -1446,7 +1446,7 @@ func mstart0() {
 	}
 	// Initialize stack guard so that we can start calling regular
 	// Go code.
-	gp.stackguard0 = gp.stack.lo + _StackGuard
+	gp.stackguard0 = gp.stack.lo + stackGuard
 	// This is the g0, so we can also call go:systemstack
 	// functions, which check stackguard1.
 	gp.stackguard1 = gp.stackguard0
@@ -1940,7 +1940,7 @@ func needm() {
 	gp := getg()
 	gp.stack.hi = getcallersp() + 1024
 	gp.stack.lo = getcallersp() - 32*1024
-	gp.stackguard0 = gp.stack.lo + _StackGuard
+	gp.stackguard0 = gp.stack.lo + stackGuard
 
 	// Initialize this thread to use the m.
 	asminit()
@@ -2640,7 +2640,7 @@ func execute(gp *g, inheritTime bool) {
 	casgstatus(gp, _Grunnable, _Grunning)
 	gp.waitsince = 0
 	gp.preempt = false
-	gp.stackguard0 = gp.stack.lo + _StackGuard
+	gp.stackguard0 = gp.stack.lo + stackGuard
 	if !inheritTime {
 		mp.p.ptr().schedtick++
 	}
@@ -3955,8 +3955,8 @@ func exitsyscall() {
 			// restore the preemption request in case we've cleared it in newstack
 			gp.stackguard0 = stackPreempt
 		} else {
-			// otherwise restore the real _StackGuard, we've spoiled it in entersyscall/entersyscallblock
-			gp.stackguard0 = gp.stack.lo + _StackGuard
+			// otherwise restore the real stackGuard, we've spoiled it in entersyscall/entersyscallblock
+			gp.stackguard0 = gp.stack.lo + stackGuard
 		}
 		gp.throwsplit = false
 
@@ -4137,7 +4137,7 @@ func syscall_runtime_BeforeFork() {
 
 	// This function is called before fork in syscall package.
 	// Code between fork and exec must not allocate memory nor even try to grow stack.
-	// Here we spoil g->_StackGuard to reliably detect any attempts to grow stack.
+	// Here we spoil g.stackguard0 to reliably detect any attempts to grow stack.
 	// runtime_AfterFork will undo this in parent process, but not in child.
 	gp.stackguard0 = stackFork
 }
@@ -4150,7 +4150,7 @@ func syscall_runtime_AfterFork() {
 	gp := getg().m.curg
 
 	// See the comments in beforefork.
-	gp.stackguard0 = gp.stack.lo + _StackGuard
+	gp.stackguard0 = gp.stack.lo + stackGuard
 
 	msigrestore(gp.m.sigmask)
 
@@ -4220,11 +4220,11 @@ func syscall_runtime_AfterExec() {
 func malg(stacksize int32) *g {
 	newg := new(g)
 	if stacksize >= 0 {
-		stacksize = round2(_StackSystem + stacksize)
+		stacksize = round2(stackSystem + stacksize)
 		systemstack(func() {
 			newg.stack = stackalloc(uint32(stacksize))
 		})
-		newg.stackguard0 = newg.stack.lo + _StackGuard
+		newg.stackguard0 = newg.stack.lo + stackGuard
 		newg.stackguard1 = ^uintptr(0)
 		// Clear the bottom word of the stack. We record g
 		// there on gsignal stack during VDSO on ARM and ARM64.
@@ -4263,7 +4263,7 @@ func newproc1(fn *funcval, callergp *g, callerpc uintptr) *g {
 	pp := mp.p.ptr()
 	newg := gfget(pp)
 	if newg == nil {
-		newg = malg(_StackMin)
+		newg = malg(stackMin)
 		casgstatus(newg, _Gidle, _Gdead)
 		allgadd(newg) // publishes with a g->status of Gdead so GC scanner doesn't look at uninitialized stack.
 	}
@@ -4467,7 +4467,7 @@ retry:
 		systemstack(func() {
 			gp.stack = stackalloc(startingStackSize)
 		})
-		gp.stackguard0 = gp.stack.lo + _StackGuard
+		gp.stackguard0 = gp.stack.lo + stackGuard
 	} else {
 		if raceenabled {
 			racemalloc(unsafe.Pointer(gp.stack.lo), gp.stack.hi-gp.stack.lo)

src/runtime/runtime1.go

@@ -286,7 +286,7 @@ func check() {
 
 	testAtomic64()
 
-	if _FixedStack != round2(_FixedStack) {
+	if fixedStack != round2(fixedStack) {
 		throw("FixedStack is not power-of-2")
 	}
 

src/runtime/signal_unix.go

@@ -1307,8 +1307,8 @@ func setGsignalStack(st *stackt, old *gsignalStack) {
 	stsp := uintptr(unsafe.Pointer(st.ss_sp))
 	gp.m.gsignal.stack.lo = stsp
 	gp.m.gsignal.stack.hi = stsp + st.ss_size
-	gp.m.gsignal.stackguard0 = stsp + _StackGuard
-	gp.m.gsignal.stackguard1 = stsp + _StackGuard
+	gp.m.gsignal.stackguard0 = stsp + stackGuard
+	gp.m.gsignal.stackguard1 = stsp + stackGuard
 }
 
 // restoreGsignalStack restores the gsignal stack to the value it had

src/runtime/signal_windows.go

@@ -321,7 +321,7 @@ func winthrow(info *exceptionrecord, r *context, gp *g) {
 	// g0 stack bounds so we have room to print the traceback. If
 	// this somehow overflows the stack, the OS will trap it.
 	g0.stack.lo = 0
-	g0.stackguard0 = g0.stack.lo + _StackGuard
+	g0.stackguard0 = g0.stack.lo + stackGuard
 	g0.stackguard1 = g0.stackguard0
 
 	print("Exception ", hex(info.exceptioncode), " ", hex(info.exceptioninformation[0]), " ", hex(info.exceptioninformation[1]), " ", hex(r.ip()), "\n")

src/runtime/stack.go

@@ -65,25 +65,25 @@ functions to make sure that this limit cannot be violated.
 */
 
 const (
-	// StackSystem is a number of additional bytes to add
+	// stackSystem is a number of additional bytes to add
 	// to each stack below the usual guard area for OS-specific
 	// purposes like signal handling. Used on Windows, Plan 9,
 	// and iOS because they do not use a separate stack.
-	_StackSystem = goos.IsWindows*512*goarch.PtrSize + goos.IsPlan9*512 + goos.IsIos*goarch.IsArm64*1024
+	stackSystem = goos.IsWindows*512*goarch.PtrSize + goos.IsPlan9*512 + goos.IsIos*goarch.IsArm64*1024
 
 	// The minimum size of stack used by Go code
-	_StackMin = 2048
+	stackMin = 2048
 
 	// The minimum stack size to allocate.
-	// The hackery here rounds FixedStack0 up to a power of 2.
-	_FixedStack0 = _StackMin + _StackSystem
-	_FixedStack1 = _FixedStack0 - 1
-	_FixedStack2 = _FixedStack1 | (_FixedStack1 >> 1)
-	_FixedStack3 = _FixedStack2 | (_FixedStack2 >> 2)
-	_FixedStack4 = _FixedStack3 | (_FixedStack3 >> 4)
-	_FixedStack5 = _FixedStack4 | (_FixedStack4 >> 8)
-	_FixedStack6 = _FixedStack5 | (_FixedStack5 >> 16)
-	_FixedStack  = _FixedStack6 + 1
+	// The hackery here rounds fixedStack0 up to a power of 2.
+	fixedStack0 = stackMin + stackSystem
+	fixedStack1 = fixedStack0 - 1
+	fixedStack2 = fixedStack1 | (fixedStack1 >> 1)
+	fixedStack3 = fixedStack2 | (fixedStack2 >> 2)
+	fixedStack4 = fixedStack3 | (fixedStack3 >> 4)
+	fixedStack5 = fixedStack4 | (fixedStack4 >> 8)
+	fixedStack6 = fixedStack5 | (fixedStack5 >> 16)
+	fixedStack  = fixedStack6 + 1
 
 	// stackNosplit is the maximum number of bytes that a chain of NOSPLIT
 	// functions can use.
@@ -96,7 +96,7 @@ const (
 	// The guard leaves enough room for a stackNosplit chain of NOSPLIT calls
 	// plus one stackSmall frame plus stackSystem bytes for the OS.
 	// This arithmetic must match that in cmd/internal/objabi/stack.go:StackLimit.
-	_StackGuard = stackNosplit + _StackSystem + abi.StackSmall
+	stackGuard = stackNosplit + stackSystem + abi.StackSmall
 )
 
 const (
@@ -204,7 +204,7 @@ func stackpoolalloc(order uint8) gclinkptr {
 			throw("bad manualFreeList")
 		}
 		osStackAlloc(s)
-		s.elemsize = _FixedStack << order
+		s.elemsize = fixedStack << order
 		for i := uintptr(0); i < _StackCacheSize; i += s.elemsize {
 			x := gclinkptr(s.base() + i)
 			x.ptr().next = s.manualFreeList
@@ -279,7 +279,7 @@ func stackcacherefill(c *mcache, order uint8) {
 		x := stackpoolalloc(order)
 		x.ptr().next = list
 		list = x
-		size += _FixedStack << order
+		size += fixedStack << order
 	}
 	unlock(&stackpool[order].item.mu)
 	c.stackcache[order].list = list
@@ -298,7 +298,7 @@ func stackcacherelease(c *mcache, order uint8) {
 		y := x.ptr().next
 		stackpoolfree(x, order)
 		x = y
-		size -= _FixedStack << order
+		size -= fixedStack << order
 	}
 	unlock(&stackpool[order].item.mu)
 	c.stackcache[order].list = x
@@ -358,10 +358,10 @@ func stackalloc(n uint32) stack {
 	// If we need a stack of a bigger size, we fall back on allocating
 	// a dedicated span.
 	var v unsafe.Pointer
-	if n < _FixedStack<<_NumStackOrders && n < _StackCacheSize {
+	if n < fixedStack<<_NumStackOrders && n < _StackCacheSize {
 		order := uint8(0)
 		n2 := n
-		for n2 > _FixedStack {
+		for n2 > fixedStack {
 			order++
 			n2 >>= 1
 		}
@@ -461,10 +461,10 @@ func stackfree(stk stack) {
 	if asanenabled {
 		asanpoison(v, n)
 	}
-	if n < _FixedStack<<_NumStackOrders && n < _StackCacheSize {
+	if n < fixedStack<<_NumStackOrders && n < _StackCacheSize {
 		order := uint8(0)
 		n2 := n
-		for n2 > _FixedStack {
+		for n2 > fixedStack {
 			order++
 			n2 >>= 1
 		}
@@ -928,7 +928,7 @@ func copystack(gp *g, newsize uintptr) {
 
 	// Swap out old stack for new one
 	gp.stack = new
-	gp.stackguard0 = new.lo + _StackGuard // NOTE: might clobber a preempt request
+	gp.stackguard0 = new.lo + stackGuard // NOTE: might clobber a preempt request
 	gp.sched.sp = new.hi - used
 	gp.stktopsp += adjinfo.delta
 
@@ -1030,7 +1030,7 @@ func newstack() {
 		if !canPreemptM(thisg.m) {
 			// Let the goroutine keep running for now.
 			// gp->preempt is set, so it will be preempted next time.
-			gp.stackguard0 = gp.stack.lo + _StackGuard
+			gp.stackguard0 = gp.stack.lo + stackGuard
 			gogo(&gp.sched) // never return
 		}
 	}
@@ -1086,7 +1086,7 @@ func newstack() {
 	// recheck the bounds on return.)
 	if f := findfunc(gp.sched.pc); f.valid() {
 		max := uintptr(funcMaxSPDelta(f))
-		needed := max + _StackGuard
+		needed := max + stackGuard
 		used := gp.stack.hi - gp.sched.sp
 		for newsize-used < needed {
 			newsize *= 2
@@ -1201,7 +1201,7 @@ func shrinkstack(gp *g) {
 	newsize := oldsize / 2
 	// Don't shrink the allocation below the minimum-sized stack
 	// allocation.
-	if newsize < _FixedStack {
+	if newsize < fixedStack {
 		return
 	}
 	// Compute how much of the stack is currently in use and only
@@ -1307,7 +1307,7 @@ func morestackc() {
 // It is a power of 2, and between _FixedStack and maxstacksize, inclusive.
 // startingStackSize is updated every GC by tracking the average size of
 // stacks scanned during the GC.
-var startingStackSize uint32 = _FixedStack
+var startingStackSize uint32 = fixedStack
 
 func gcComputeStartingStackSize() {
 	if debug.adaptivestackstart == 0 {
@@ -1333,17 +1333,17 @@ func gcComputeStartingStackSize() {
 		p.scannedStacks = 0
 	}
 	if scannedStacks == 0 {
-		startingStackSize = _FixedStack
+		startingStackSize = fixedStack
 		return
 	}
-	avg := scannedStackSize/scannedStacks + _StackGuard
-	// Note: we add _StackGuard to ensure that a goroutine that
+	avg := scannedStackSize/scannedStacks + stackGuard
+	// Note: we add stackGuard to ensure that a goroutine that
 	// uses the average space will not trigger a growth.
 	if avg > uint64(maxstacksize) {
 		avg = uint64(maxstacksize)
 	}
-	if avg < _FixedStack {
-		avg = _FixedStack
+	if avg < fixedStack {
+		avg = fixedStack
 	}
 	// Note: maxstacksize fits in 30 bits, so avg also does.
 	startingStackSize = uint32(round2(int32(avg)))

src/runtime/sys_aix_ppc64.s

@@ -210,7 +210,7 @@ TEXT tstart<>(SB),NOSPLIT,$0
 	MOVD	R3, (g_stack+stack_hi)(g)
 	SUB	$(const_threadStackSize), R3		// stack size
 	MOVD	R3, (g_stack+stack_lo)(g)
-	ADD	$const__StackGuard, R3
+	ADD	$const_stackGuard, R3
 	MOVD	R3, g_stackguard0(g)
 	MOVD	R3, g_stackguard1(g)
 

src/runtime/sys_solaris_amd64.s

@@ -105,7 +105,7 @@ TEXT runtime·tstart_sysvicall(SB),NOSPLIT,$0
 	MOVQ	AX, (g_stack+stack_hi)(DX)
 	SUBQ	$(0x100000), AX		// stack size
 	MOVQ	AX, (g_stack+stack_lo)(DX)
-	ADDQ	$const__StackGuard, AX
+	ADDQ	$const_stackGuard, AX
 	MOVQ	AX, g_stackguard0(DX)
 	MOVQ	AX, g_stackguard1(DX)
 

src/runtime/sys_windows_386.s

@@ -181,7 +181,7 @@ TEXT tstart<>(SB),NOSPLIT,$8-4
 	MOVL	AX, (g_stack+stack_hi)(DX)
 	SUBL	$(64*1024), AX		// initial stack size (adjusted later)
 	MOVL	AX, (g_stack+stack_lo)(DX)
-	ADDL	$const__StackGuard, AX
+	ADDL	$const_stackGuard, AX
 	MOVL	AX, g_stackguard0(DX)
 	MOVL	AX, g_stackguard1(DX)
 

src/runtime/sys_windows_amd64.s

@@ -208,7 +208,7 @@ TEXT runtime·tstart_stdcall(SB),NOSPLIT|NOFRAME,$0
 	MOVQ	AX, (g_stack+stack_hi)(DX)
 	SUBQ	$(64*1024), AX		// initial stack size (adjusted later)
 	MOVQ	AX, (g_stack+stack_lo)(DX)
-	ADDQ	$const__StackGuard, AX
+	ADDQ	$const_stackGuard, AX
 	MOVQ	AX, g_stackguard0(DX)
 	MOVQ	AX, g_stackguard1(DX)