runtime: merge slice and sliceStruct

By removing type slice, renaming type sliceStruct to type slice and
whacking until it compiles.

Has a pleasing net reduction of conversions.

Fixes #10188

Change-Id: I77202b8df637185b632fd7875a1fdd8d52c7a83c
Reviewed-on: https://go-review.googlesource.com/8770
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

10 files changed, 36 insertions, 46 deletions

diff --git a/src/runtime/alg.go b/src/runtime/alg.go
index 659c8d7d79..f24ebd1fb2 100644
--- a/src/runtime/alg.go
+++ b/src/runtime/alg.go
@@ -281,7 +281,7 @@ func stringHash(s string, seed uintptr) uintptr {
 }
 
 func bytesHash(b []byte, seed uintptr) uintptr {
-	s := (*sliceStruct)(unsafe.Pointer(&b))
+	s := (*slice)(unsafe.Pointer(&b))
 	return memhash(s.array, seed, uintptr(s.len))
 }
 
@@ -305,7 +305,7 @@ func ifaceHash(i interface {
 
 // Testing adapter for memclr
 func memclrBytes(b []byte) {
-	s := (*sliceStruct)(unsafe.Pointer(&b))
+	s := (*slice)(unsafe.Pointer(&b))
 	memclr(s.array, uintptr(s.len))
 }
 
diff --git a/src/runtime/cpuprof.go b/src/runtime/cpuprof.go
index 055b2af018..0790852d97 100644
--- a/src/runtime/cpuprof.go
+++ b/src/runtime/cpuprof.go
@@ -396,8 +396,8 @@ Flush:
 }
 
 func uintptrBytes(p []uintptr) (ret []byte) {
-	pp := (*sliceStruct)(unsafe.Pointer(&p))
-	rp := (*sliceStruct)(unsafe.Pointer(&ret))
+	pp := (*slice)(unsafe.Pointer(&p))
+	rp := (*slice)(unsafe.Pointer(&ret))
 
 	rp.array = pp.array
 	rp.len = pp.len * int(unsafe.Sizeof(p[0]))
diff --git a/src/runtime/export_test.go b/src/runtime/export_test.go
index 58ac34283f..905218b22b 100644
--- a/src/runtime/export_test.go
+++ b/src/runtime/export_test.go
@@ -76,8 +76,10 @@ func GCMask(x interface{}) (ret []byte) {
 	s := (*slice)(unsafe.Pointer(&ret))
 	systemstack(func() {
 		var len uintptr
-		getgcmask(e.data, e._type, &s.array, &len)
-		s.len = uint(len)
+		var a *byte
+		getgcmask(e.data, e._type, &a, &len)
+		s.array = unsafe.Pointer(a)
+		s.len = int(len)
 		s.cap = s.len
 	})
 	return
diff --git a/src/runtime/mbarrier.go b/src/runtime/mbarrier.go
index 4233f01a99..2e3e4d8041 100644
--- a/src/runtime/mbarrier.go
+++ b/src/runtime/mbarrier.go
@@ -355,7 +355,7 @@ func typedslicecopy(typ *_type, dst, src slice) int {
 
 	if !needwb() {
 		memmove(dstp, srcp, uintptr(n)*typ.size)
-		return int(n)
+		return n
 	}
 
 	systemstack(func() {
@@ -365,7 +365,7 @@ func typedslicecopy(typ *_type, dst, src slice) int {
 			// out of the array they point into.
 			dstp = add(dstp, uintptr(n-1)*typ.size)
 			srcp = add(srcp, uintptr(n-1)*typ.size)
-			i := uint(0)
+			i := 0
 			for {
 				typedmemmove(typ, dstp, srcp)
 				if i++; i >= n {
@@ -377,7 +377,7 @@ func typedslicecopy(typ *_type, dst, src slice) int {
 		} else {
 			// Copy forward, being careful not to move dstp/srcp
 			// out of the array they point into.
-			i := uint(0)
+			i := 0
 			for {
 				typedmemmove(typ, dstp, srcp)
 				if i++; i >= n {
diff --git a/src/runtime/mheap.go b/src/runtime/mheap.go
index c78005c9af..c5de8218c2 100644
--- a/src/runtime/mheap.go
+++ b/src/runtime/mheap.go
@@ -148,12 +148,12 @@ func recordspan(vh unsafe.Pointer, p unsafe.Pointer) {
 		}
 		var new []*mspan
 		sp := (*slice)(unsafe.Pointer(&new))
-		sp.array = (*byte)(sysAlloc(uintptr(n)*ptrSize, &memstats.other_sys))
+		sp.array = sysAlloc(uintptr(n)*ptrSize, &memstats.other_sys)
 		if sp.array == nil {
 			throw("runtime: cannot allocate memory")
 		}
-		sp.len = uint(len(h_allspans))
-		sp.cap = uint(n)
+		sp.len = len(h_allspans)
+		sp.cap = n
 		if len(h_allspans) > 0 {
 			copy(new, h_allspans)
 			// Don't free the old array if it's referenced by sweep.
@@ -256,9 +256,9 @@ func mHeap_Init(h *mheap, spans_size uintptr) {
 	}
 
 	sp := (*slice)(unsafe.Pointer(&h_spans))
-	sp.array = (*byte)(unsafe.Pointer(h.spans))
-	sp.len = uint(spans_size / ptrSize)
-	sp.cap = uint(spans_size / ptrSize)
+	sp.array = unsafe.Pointer(h.spans)
+	sp.len = int(spans_size / ptrSize)
+	sp.cap = int(spans_size / ptrSize)
 }
 
 func mHeap_MapSpans(h *mheap) {
diff --git a/src/runtime/print1.go b/src/runtime/print1.go
index ba5799182a..6eff38168d 100644
--- a/src/runtime/print1.go
+++ b/src/runtime/print1.go
@@ -13,9 +13,9 @@ type hex uint64
 func bytes(s string) (ret []byte) {
 	rp := (*slice)(unsafe.Pointer(&ret))
 	sp := (*_string)(noescape(unsafe.Pointer(&s)))
-	rp.array = sp.str
-	rp.len = uint(sp.len)
-	rp.cap = uint(sp.len)
+	rp.array = unsafe.Pointer(sp.str)
+	rp.len = sp.len
+	rp.cap = sp.len
 	return
 }
 
diff --git a/src/runtime/runtime2.go b/src/runtime/runtime2.go
index 1f4f0daec4..cdbaebcc09 100644
--- a/src/runtime/runtime2.go
+++ b/src/runtime/runtime2.go
@@ -87,12 +87,6 @@ type eface struct {
 	data  unsafe.Pointer
 }
 
-type slice struct {
-	array *byte // actual data
-	len   uint  // number of elements
-	cap   uint  // allocated number of elements
-}
-
 // A guintptr holds a goroutine pointer, but typed as a uintptr
 // to bypass write barriers. It is used in the Gobuf goroutine state.
 //
diff --git a/src/runtime/select.go b/src/runtime/select.go
index 98ac5a3d61..2dd541b530 100644
--- a/src/runtime/select.go
+++ b/src/runtime/select.go
@@ -159,7 +159,7 @@ func selectdefaultImpl(sel *hselect, callerpc uintptr, so uintptr) {
 }
 
 func sellock(sel *hselect) {
-	lockslice := sliceStruct{unsafe.Pointer(sel.lockorder), int(sel.ncase), int(sel.ncase)}
+	lockslice := slice{unsafe.Pointer(sel.lockorder), int(sel.ncase), int(sel.ncase)}
 	lockorder := *(*[]*hchan)(unsafe.Pointer(&lockslice))
 	var c *hchan
 	for _, c0 := range lockorder {
@@ -181,7 +181,7 @@ func selunlock(sel *hselect) {
 	// Now if the first M touches sel, it will access freed memory.
 	n := int(sel.ncase)
 	r := 0
-	lockslice := sliceStruct{unsafe.Pointer(sel.lockorder), n, n}
+	lockslice := slice{unsafe.Pointer(sel.lockorder), n, n}
 	lockorder := *(*[]*hchan)(unsafe.Pointer(&lockslice))
 	// skip the default case
 	if n > 0 && lockorder[0] == nil {
@@ -221,7 +221,7 @@ func selectgoImpl(sel *hselect) (uintptr, uint16) {
 		print("select: sel=", sel, "\n")
 	}
 
-	scaseslice := sliceStruct{unsafe.Pointer(&sel.scase), int(sel.ncase), int(sel.ncase)}
+	scaseslice := slice{unsafe.Pointer(&sel.scase), int(sel.ncase), int(sel.ncase)}
 	scases := *(*[]scase)(unsafe.Pointer(&scaseslice))
 
 	var t0 int64
@@ -241,7 +241,7 @@ func selectgoImpl(sel *hselect) (uintptr, uint16) {
 	// optimizing (and needing to test).
 
 	// generate permuted order
-	pollslice := sliceStruct{unsafe.Pointer(sel.pollorder), int(sel.ncase), int(sel.ncase)}
+	pollslice := slice{unsafe.Pointer(sel.pollorder), int(sel.ncase), int(sel.ncase)}
 	pollorder := *(*[]uint16)(unsafe.Pointer(&pollslice))
 	for i := 0; i < int(sel.ncase); i++ {
 		pollorder[i] = uint16(i)
@@ -255,7 +255,7 @@ func selectgoImpl(sel *hselect) (uintptr, uint16) {
 
 	// sort the cases by Hchan address to get the locking order.
 	// simple heap sort, to guarantee n log n time and constant stack footprint.
-	lockslice := sliceStruct{unsafe.Pointer(sel.lockorder), int(sel.ncase), int(sel.ncase)}
+	lockslice := slice{unsafe.Pointer(sel.lockorder), int(sel.ncase), int(sel.ncase)}
 	lockorder := *(*[]*hchan)(unsafe.Pointer(&lockslice))
 	for i := 0; i < int(sel.ncase); i++ {
 		j := i
diff --git a/src/runtime/slice.go b/src/runtime/slice.go
index ae46d9c1ac..cf2510aeb2 100644
--- a/src/runtime/slice.go
+++ b/src/runtime/slice.go
@@ -8,14 +8,14 @@ import (
 	"unsafe"
 )
 
-type sliceStruct struct {
+type slice struct {
 	array unsafe.Pointer
 	len   int
 	cap   int
 }
 
 // TODO: take uintptrs instead of int64s?
-func makeslice(t *slicetype, len64 int64, cap64 int64) sliceStruct {
+func makeslice(t *slicetype, len64, cap64 int64) slice {
 	// NOTE: The len > MaxMem/elemsize check here is not strictly necessary,
 	// but it produces a 'len out of range' error instead of a 'cap out of range' error
 	// when someone does make([]T, bignumber). 'cap out of range' is true too,
@@ -30,10 +30,10 @@ func makeslice(t *slicetype, len64 int64, cap64 int64) sliceStruct {
 		panic(errorString("makeslice: cap out of range"))
 	}
 	p := newarray(t.elem, uintptr(cap))
-	return sliceStruct{p, len, cap}
+	return slice{p, len, cap}
 }
 
-func growslice(t *slicetype, old sliceStruct, n int) sliceStruct {
+func growslice(t *slicetype, old slice, n int) slice {
 	if n < 1 {
 		panic(errorString("growslice: invalid n"))
 	}
@@ -52,7 +52,7 @@ func growslice(t *slicetype, old sliceStruct, n int) sliceStruct {
 	if et.size == 0 {
 		// append should not create a slice with nil pointer but non-zero len.
 		// We assume that append doesn't need to preserve old.array in this case.
-		return sliceStruct{unsafe.Pointer(&zerobase), old.len, cap}
+		return slice{unsafe.Pointer(&zerobase), old.len, cap}
 	}
 
 	newcap := old.cap
@@ -91,10 +91,10 @@ func growslice(t *slicetype, old sliceStruct, n int) sliceStruct {
 		}
 	}
 
-	return sliceStruct{p, old.len, newcap}
+	return slice{p, old.len, newcap}
 }
 
-func slicecopy(to sliceStruct, fm sliceStruct, width uintptr) int {
+func slicecopy(to, fm slice, width uintptr) int {
 	if fm.len == 0 || to.len == 0 {
 		return 0
 	}
diff --git a/src/runtime/string.go b/src/runtime/string.go
index 0ba309cf02..a5851b7abc 100644
--- a/src/runtime/string.go
+++ b/src/runtime/string.go
@@ -148,7 +148,7 @@ func stringtoslicebytetmp(s string) []byte {
 	// for i, c := range []byte(str)
 
 	str := (*stringStruct)(unsafe.Pointer(&s))
-	ret := slice{array: (*byte)(str.str), len: uint(str.len), cap: uint(str.len)}
+	ret := slice{array: unsafe.Pointer(str.str), len: str.len, cap: str.len}
 	return *(*[]byte)(unsafe.Pointer(&ret))
 }
 
@@ -266,9 +266,7 @@ func rawstring(size int) (s string, b []byte) {
 	(*stringStruct)(unsafe.Pointer(&s)).str = p
 	(*stringStruct)(unsafe.Pointer(&s)).len = size
 
-	(*slice)(unsafe.Pointer(&b)).array = (*uint8)(p)
-	(*slice)(unsafe.Pointer(&b)).len = uint(size)
-	(*slice)(unsafe.Pointer(&b)).cap = uint(size)
+	*(*slice)(unsafe.Pointer(&b)) = slice{p, size, size}
 
 	for {
 		ms := maxstring
@@ -286,9 +284,7 @@ func rawbyteslice(size int) (b []byte) {
 		memclr(add(p, uintptr(size)), cap-uintptr(size))
 	}
 
-	(*slice)(unsafe.Pointer(&b)).array = (*uint8)(p)
-	(*slice)(unsafe.Pointer(&b)).len = uint(size)
-	(*slice)(unsafe.Pointer(&b)).cap = uint(cap)
+	*(*slice)(unsafe.Pointer(&b)) = slice{p, size, int(cap)}
 	return
 }
 
@@ -303,9 +299,7 @@ func rawruneslice(size int) (b []rune) {
 		memclr(add(p, uintptr(size)*4), mem-uintptr(size)*4)
 	}
 
-	(*slice)(unsafe.Pointer(&b)).array = (*uint8)(p)
-	(*slice)(unsafe.Pointer(&b)).len = uint(size)
-	(*slice)(unsafe.Pointer(&b)).cap = uint(mem / 4)
+	*(*slice)(unsafe.Pointer(&b)) = slice{p, size, int(mem / 4)}
 	return
 }