runtime: delete dead code called from C.

printf, vprintf, snprintf, gc_m_ptr, gc_g_ptr, gc_itab_ptr, gc_unixnanotime.

These were called from C.
There is no more C.

Now that vprintf is gone, delete roundup, which is unsafe (see CL 2814).

Change-Id: If8a7b727d497ffa13165c0d3a1ed62abc18f008c
Reviewed-on: https://go-review.googlesource.com/2824Reviewed-by: Austin Clements <austin@google.com>

src/runtime/mgc.go

@@ -2551,7 +2551,6 @@ func getgcmask(p unsafe.Pointer, t *_type, mask **byte, len *uintptr) {
 }
 
 func unixnanotime() int64 {
-	var now int64
-	gc_unixnanotime(&now)
-	return now
+	sec, nsec := time_now()
+	return sec*1e9 + int64(nsec)
 }

src/runtime/mgc0.go

@@ -6,26 +6,6 @@ package runtime
 
 import "unsafe"
 
-// Called from C. Returns the Go type *m.
-func gc_m_ptr(ret *interface{}) {
-	*ret = (*m)(nil)
-}
-
-// Called from C. Returns the Go type *g.
-func gc_g_ptr(ret *interface{}) {
-	*ret = (*g)(nil)
-}
-
-// Called from C. Returns the Go type *itab.
-func gc_itab_ptr(ret *interface{}) {
-	*ret = (*itab)(nil)
-}
-
-func gc_unixnanotime(now *int64) {
-	sec, nsec := time_now()
-	*now = sec*1e9 + int64(nsec)
-}
-
 //go:linkname runtime_debug_freeOSMemory runtime/debug.freeOSMemory
 func runtime_debug_freeOSMemory() {
 	gogc(2) // force GC and do eager sweep

src/runtime/print1.go

@@ -19,28 +19,6 @@ func bytes(s string) (ret []byte) {
 	return
 }
 
-// printf is only called from C code. It has no type information for the args,
-// but C stacks are ignored by the garbage collector anyway, so having
-// type information would not add anything.
-//go:nosplit
-func printf(s *byte) {
-	vprintf(gostringnocopy(s), add(unsafe.Pointer(&s), unsafe.Sizeof(s)))
-}
-
-// sprintf is only called from C code. It has no type information for the args,
-// but C stacks are ignored by the garbage collector anyway, so having
-// type information would not add anything.
-//go:nosplit
-func snprintf(dst *byte, n int32, s *byte) {
-	buf := (*[1 << 30]byte)(unsafe.Pointer(dst))[0:n:n]
-
-	gp := getg()
-	gp.writebuf = buf[0:0 : n-1] // leave room for NUL, this is called from C
-	vprintf(gostringnocopy(s), add(unsafe.Pointer(&s), unsafe.Sizeof(s)))
-	buf[len(gp.writebuf)] = '\x00'
-	gp.writebuf = nil
-}
-
 var debuglock mutex
 
 // The compiler emits calls to printlock and printunlock around
@@ -85,16 +63,6 @@ func gwrite(b []byte) {
 	gp.writebuf = gp.writebuf[:len(gp.writebuf)+n]
 }
 
-func prints(s *byte) {
-	b := (*[1 << 30]byte)(unsafe.Pointer(s))
-	for i := 0; ; i++ {
-		if b[i] == 0 {
-			gwrite(b[:i])
-			return
-		}
-	}
-}
-
 func printsp() {
 	print(" ")
 }
@@ -103,92 +71,6 @@ func printnl() {
 	print("\n")
 }
 
-// Very simple printf.  Only for debugging prints.
-// Do not add to this without checking with Rob.
-func vprintf(str string, arg unsafe.Pointer) {
-	printlock()
-
-	s := bytes(str)
-	start := 0
-	i := 0
-	for ; i < len(s); i++ {
-		if s[i] != '%' {
-			continue
-		}
-		if i > start {
-			gwrite(s[start:i])
-		}
-		if i++; i >= len(s) {
-			break
-		}
-		var siz uintptr
-		switch s[i] {
-		case 't', 'c':
-			siz = 1
-		case 'd', 'x': // 32-bit
-			arg = roundup(arg, 4)
-			siz = 4
-		case 'D', 'U', 'X', 'f': // 64-bit
-			arg = roundup(arg, unsafe.Sizeof(uintreg(0)))
-			siz = 8
-		case 'C':
-			arg = roundup(arg, unsafe.Sizeof(uintreg(0)))
-			siz = 16
-		case 'p', 's': // pointer-sized
-			arg = roundup(arg, unsafe.Sizeof(uintptr(0)))
-			siz = unsafe.Sizeof(uintptr(0))
-		case 'S': // pointer-aligned but bigger
-			arg = roundup(arg, unsafe.Sizeof(uintptr(0)))
-			siz = unsafe.Sizeof(string(""))
-		case 'a': // pointer-aligned but bigger
-			arg = roundup(arg, unsafe.Sizeof(uintptr(0)))
-			siz = unsafe.Sizeof([]byte{})
-		case 'i', 'e': // pointer-aligned but bigger
-			arg = roundup(arg, unsafe.Sizeof(uintptr(0)))
-			siz = unsafe.Sizeof(interface{}(nil))
-		}
-		switch s[i] {
-		case 'a':
-			printslice(*(*[]byte)(arg))
-		case 'c':
-			printbyte(*(*byte)(arg))
-		case 'd':
-			printint(int64(*(*int32)(arg)))
-		case 'D':
-			printint(int64(*(*int64)(arg)))
-		case 'e':
-			printeface(*(*interface{})(arg))
-		case 'f':
-			printfloat(*(*float64)(arg))
-		case 'C':
-			printcomplex(*(*complex128)(arg))
-		case 'i':
-			printiface(*(*fInterface)(arg))
-		case 'p':
-			printpointer(*(*unsafe.Pointer)(arg))
-		case 's':
-			prints(*(**byte)(arg))
-		case 'S':
-			printstring(*(*string)(arg))
-		case 't':
-			printbool(*(*bool)(arg))
-		case 'U':
-			printuint(*(*uint64)(arg))
-		case 'x':
-			printhex(uint64(*(*uint32)(arg)))
-		case 'X':
-			printhex(*(*uint64)(arg))
-		}
-		arg = add(arg, siz)
-		start = i + 1
-	}
-	if start < i {
-		gwrite(s[start:i])
-	}
-
-	printunlock()
-}
-
 func printpc(p unsafe.Pointer) {
 	print("PC=", hex(uintptr(p)))
 }

src/runtime/stubs.go

@@ -17,12 +17,6 @@ func add(p unsafe.Pointer, x uintptr) unsafe.Pointer {
 	return unsafe.Pointer(uintptr(p) + x)
 }
 
-// n must be a power of 2
-func roundup(p unsafe.Pointer, n uintptr) unsafe.Pointer {
-	delta := -uintptr(p) & (n - 1)
-	return unsafe.Pointer(uintptr(p) + delta)
-}
-
 func getg() *g
 
 // mcall switches from the g to the g0 stack and invokes fn(g),