runtime: use efaceOf where applicable

Prepared with gofmt -r.

Change-Id: Ifea325c209d800b5692d318955930b10debb548b
Reviewed-on: https://go-review.googlesource.com/c/go/+/198494
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/runtime/cgocall.go

@@ -411,7 +411,7 @@ func cgoCheckPointer(ptr interface{}, arg interface{}) {
 		return
 	}
 
-	ep := (*eface)(unsafe.Pointer(&ptr))
+	ep := efaceOf(&ptr)
 	t := ep._type
 
 	top := true
@@ -423,7 +423,7 @@ func cgoCheckPointer(ptr interface{}, arg interface{}) {
 		if p == nil || !cgoIsGoPointer(p) {
 			return
 		}
-		aep := (*eface)(unsafe.Pointer(&arg))
+		aep := efaceOf(&arg)
 		switch aep._type.kind & kindMask {
 		case kindBool:
 			if t.kind&kindMask == kindUnsafePointer {
@@ -650,7 +650,7 @@ func cgoCheckResult(val interface{}) {
 		return
 	}
 
-	ep := (*eface)(unsafe.Pointer(&val))
+	ep := efaceOf(&val)
 	t := ep._type
 	cgoCheckArg(t, ep.data, t.kind&kindDirectIface == 0, false, cgoResultFail)
 }

src/runtime/iface.go

@@ -295,11 +295,11 @@ var (
 	stringEface interface{} = stringInterfacePtr("")
 	sliceEface  interface{} = sliceInterfacePtr(nil)
 
-	uint16Type *_type = (*eface)(unsafe.Pointer(&uint16Eface))._type
-	uint32Type *_type = (*eface)(unsafe.Pointer(&uint32Eface))._type
-	uint64Type *_type = (*eface)(unsafe.Pointer(&uint64Eface))._type
-	stringType *_type = (*eface)(unsafe.Pointer(&stringEface))._type
-	sliceType  *_type = (*eface)(unsafe.Pointer(&sliceEface))._type
+	uint16Type *_type = efaceOf(&uint16Eface)._type
+	uint32Type *_type = efaceOf(&uint32Eface)._type
+	uint64Type *_type = efaceOf(&uint64Eface)._type
+	stringType *_type = efaceOf(&stringEface)._type
+	sliceType  *_type = efaceOf(&sliceEface)._type
 )
 
 // The conv and assert functions below do very similar things.