code review 119360043: runtime: convert hash functions to Go calling convention.

src/pkg/runtime/stubs.go

 // Copyright 2014 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 package runtime
 
 import "unsafe"
 
 // Declarations for runtime services implemented in C or assembly.
 // C implementations of these functions are in stubs.goc.
@@ skipping 102 matching lines @@
 var nohashcode uintptr
 
 // Go version of runtime.throw.
 // in panic.c
 func gothrow(s string)
 
 func golock(x *lock)
 func gounlock(x *lock)
 func semacquire(*uint32, bool)
 func semrelease(*uint32)
+
+// Return the Go equivalent of the C Alg structure.
+// TODO: at some point Go will hold the truth for the layout
+// of runtime structures and C will be derived from it (if
+// needed at all).  At that point this function can go away.
+type goalgtype struct {
+        // function for hashing objects of this type
+        // (ptr to object, size, seed) -> hash
+        hash func(unsafe.Pointer, uintptr, uintptr) uintptr
+}
+
+func goalg(a *alg) *goalgtype {
+        return (*goalgtype)(unsafe.Pointer(a))
+}
+
+// noescape hides a pointer from escape analysis.  noescape is
+// the identity function but escape analysis doesn't think the
+// output depends on the input.  noescape is inlined and currently
+// compiles down to a single xor instruction.
+// USE CAREFULLY!
+func noescape(p unsafe.Pointer) unsafe.Pointer {
+        x := uintptr(p)
+        return unsafe.Pointer(x ^ 0)
+}