runtime: more cleanups

Move timenow thunk into time.s
Move declarations for generic c/asm services into stubs.go

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/137360043

src/runtime/asm_386.s

@@ -2241,9 +2241,6 @@ TEXT runtime·duffcopy(SB), NOSPLIT, $0-0
 	
 	RET
 
-TEXT runtime·timenow(SB), NOSPLIT, $0-0
-	JMP	time·now(SB)
-
 TEXT runtime·fastrand1(SB), NOSPLIT, $0-4
 	get_tls(CX)
 	MOVL	g(CX), AX

src/runtime/asm_amd64.s

@@ -2186,9 +2186,6 @@ TEXT runtime·duffcopy(SB), NOSPLIT, $0-0
 
 	RET
 
-TEXT runtime·timenow(SB), NOSPLIT, $0-0
-	JMP	time·now(SB)
-
 TEXT runtime·fastrand1(SB), NOSPLIT, $0-4
 	get_tls(CX)
 	MOVQ	g(CX), AX

src/runtime/asm_amd64p32.s

@@ -1069,9 +1069,6 @@ eqret:
 	MOVB	AX, ret+24(FP)
 	RET
 
-TEXT runtime·timenow(SB), NOSPLIT, $0-0
-	JMP	time·now(SB)
-
 TEXT runtime·fastrand1(SB), NOSPLIT, $0-4
 	get_tls(CX)
 	MOVL	g(CX), AX

src/runtime/asm_arm.s

@@ -848,9 +848,6 @@ _sib_notfound:
 	MOVW	R0, ret+12(FP)
 	RET
 
-TEXT runtime·timenow(SB),NOSPLIT,$0-0
-	B	time·now(SB)
-
 // A Duff's device for zeroing memory.
 // The compiler jumps to computed addresses within
 // this routine to zero chunks of memory.  Do not

src/runtime/extern.go

@@ -126,8 +126,6 @@ func Callers(skip int, pc []uintptr) int {
 	return callers(skip, &pc[0], len(pc))
 }
 
-func getgoroot() string
-
 // GOROOT returns the root of the Go tree.
 // It uses the GOROOT environment variable, if set,
 // or else the root used during the Go build.

src/runtime/mgc0.go

@@ -28,8 +28,6 @@ func gc_notype_ptr(ret *interface{}) {
 	*ret = x
 }
 
-func timenow() (sec int64, nsec int32)
-
 func gc_unixnanotime(now *int64) {
 	sec, nsec := timenow()
 	*now = sec*1e9 + int64(nsec)

src/runtime/mprof.go

@@ -295,9 +295,6 @@ func SetBlockProfileRate(rate int) {
 	atomicstore64(&blockprofilerate, uint64(r))
 }
 
-func fastrand1() uint32     // assembly
-func readgstatus(*g) uint32 // proc.c
-
 func blockevent(cycles int64, skip int) {
 	if cycles <= 0 {
 		return

src/runtime/stubs.go

@@ -28,6 +28,7 @@ func getg() *g
 func acquirem() *m
 func releasem(mp *m)
 func gomcache() *mcache
+func readgstatus(*g) uint32 // proc.c
 
 // mcall switches from the g to the g0 stack and invokes fn(g),
 // where g is the goroutine that made the call.
@@ -121,6 +122,9 @@ func unlockOSThread()
 // exported value for testing
 var hashLoad = loadFactor
 
+// in asm_*.s
+func fastrand1() uint32
+
 // in asm_*.s
 //go:noescape
 func memeq(a, b unsafe.Pointer, size uintptr) bool
@@ -229,3 +233,6 @@ func rt0_go()
 // to deferreturn.
 // in asm_*.s
 func return0()
+
+// thunk to call time.now.
+func timenow() (sec int64, nsec int32)

src/runtime/thunk.s

@@ -157,3 +157,6 @@ TEXT runtime·main_init(SB),NOSPLIT,$0-0
 
 TEXT runtime·main_main(SB),NOSPLIT,$0-0
 	JMP	main·main(SB)
+
+TEXT runtime·timenow(SB), NOSPLIT, $0-0
+	JMP	time·now(SB)