runtime: finish converting iface.goc to iface.go

LGTM=bradfitz, dvyukov
R=golang-codereviews, bradfitz, dvyukov
CC=golang-codereviews, iant, khr
https://golang.org/cl/131510043

src/pkg/runtime/heapdump.c

@@ -584,7 +584,10 @@ itab_callback(Itab *tab)
 static void
 dumpitabs(void)
 {
-	runtime·iterate_itabs(itab_callback);
+	void (*fn)(Itab*);
+	
+	fn = itab_callback;
+	runtime·iterate_itabs(&fn);
 }
 
 static void

src/pkg/runtime/iface.go

@@ -425,3 +425,16 @@ func efacethash(e interface{}) uint32 {
 	}
 	return t.hash
 }
+
+func iterate_itabs(fn func(*itab)) {
+	for _, h := range hash {
+		for ; h != nil; h = h.link {
+			fn(h)
+		}
+	}
+}
+
+func ifaceE2I2(inter *interfacetype, e interface{}, r *fInterface) (ok bool) {
+	*r, ok = assertE2I2(inter, e)
+	return
+}

src/pkg/runtime/iface.goc

-// Copyright 2009 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
-#include "runtime.h"
-#include "arch_GOARCH.h"
-#include "type.h"
-#include "typekind.h"
-#include "malloc.h"
-#include "../../cmd/ld/textflag.h"
-
-extern	Itab*	runtime·hash[1009];
-extern	Mutex	runtime·ifaceLock;
-
-// TODO: delete this when no longer used (ifaceE2I2 is all that's left)
-static Itab*
-itab(InterfaceType *inter, Type *type, int32 canfail)
-{
-	int32 locked;
-	int32 ni;
-	Method *t, *et;
-	IMethod *i, *ei;
-	uint32 h;
-	String *iname, *ipkgPath;
-	Itab *m;
-	UncommonType *x;
-	Type *itype;
-	Eface err;
-
-	if(inter->mhdr.len == 0)
-		runtime·throw("internal error - misuse of itab");
-
-	locked = 0;
-
-	// easy case
-	x = type->x;
-	if(x == nil) {
-		if(canfail)
-			return nil;
-		iname = inter->m[0].name;
-		goto throw;
-	}
-
-	// compiler has provided some good hash codes for us.
-	h = inter->typ.hash;
-	h += 17 * type->hash;
-	// TODO(rsc): h += 23 * x->mhash ?
-	h %= nelem(runtime·hash);
-
-	// look twice - once without lock, once with.
-	// common case will be no lock contention.
-	for(locked=0; locked<2; locked++) {
-		if(locked)
-			runtime·lock(&runtime·ifaceLock);
-		for(m=runtime·atomicloadp(&runtime·hash[h]); m!=nil; m=m->link) {
-			if(m->inter == inter && m->type == type) {
-				if(m->bad) {
-					m = nil;
-					if(!canfail) {
-						// this can only happen if the conversion
-						// was already done once using the , ok form
-						// and we have a cached negative result.
-						// the cached result doesn't record which
-						// interface function was missing, so jump
-						// down to the interface check, which will
-						// do more work but give a better error.
-						goto search;
-					}
-				}
-				if(locked)
-					runtime·unlock(&runtime·ifaceLock);
-				return m;
-			}
-		}
-	}
-
-	ni = inter->mhdr.len;
-	m = runtime·persistentalloc(sizeof(*m) + ni*sizeof m->fun[0], 0, &mstats.other_sys);
-	m->inter = inter;
-	m->type = type;
-
-search:
-	// both inter and type have method sorted by name,
-	// and interface names are unique,
-	// so can iterate over both in lock step;
-	// the loop is O(ni+nt) not O(ni*nt).
-	i = inter->m;
-	ei = i + inter->mhdr.len;
-	t = x->m;
-	et = t + x->mhdr.len;
-	for(; i < ei; i++) {
-		itype = i->type;
-		iname = i->name;
-		ipkgPath = i->pkgPath;
-		for(;; t++) {
-			if(t >= et) {
-				if(!canfail) {
-				throw:
-					// didn't find method
-					runtime·newTypeAssertionError(
-						nil, type->string, inter->typ.string,
-						iname, &err);
-					if(locked)
-						runtime·unlock(&runtime·ifaceLock);
-					runtime·panic(err);
-					return nil;	// not reached
-				}
-				m->bad = 1;
-				goto out;
-			}
-			if(t->mtyp == itype && t->name == iname && t->pkgPath == ipkgPath)
-				break;
-		}
-		if(m)
-			m->fun[i - inter->m] = t->ifn;
-	}
-
-out:
-	if(!locked)
-		runtime·panicstring("invalid itab locking");
-	m->link = runtime·hash[h];
-	runtime·atomicstorep(&runtime·hash[h], m);
-	runtime·unlock(&runtime·ifaceLock);
-	if(m->bad)
-		return nil;
-	return m;
-}
-
-// call the callback for every itab that is currently allocated.
-void
-runtime·iterate_itabs(void (*callback)(Itab*))
-{
-	int32 i;
-	Itab *tab;
-
-	for(i = 0; i < nelem(runtime·hash); i++) {
-		for(tab = runtime·hash[i]; tab != nil; tab = tab->link) {
-			callback(tab);
-		}
-	}
-}
-
-// Still in C because it is called from C for finalizers.  This will
-// get converted to Go in a separate CL.  This is the last user of
-// the C version of itab().
-bool
-runtime·ifaceE2I2(InterfaceType *inter, Eface e, Iface *ret)
-{
-	ret->tab = itab(inter, e.type, 1);
-	if(ret->tab == nil)
-		return false;
-	ret->data = e.data;
-	return true;
-}

src/pkg/runtime/runtime.h

@@ -959,7 +959,7 @@ void	_rt0_go(void);
 void*	runtime·funcdata(Func*, int32);
 void	runtime·setmaxthreads_m(void);
 G*	runtime·timejump(void);
-void	runtime·iterate_itabs(void (*callback)(Itab*));
+void	runtime·iterate_itabs(void (**callback)(Itab*));
 void	runtime·iterate_finq(void (*callback)(FuncVal*, byte*, uintptr, Type*, PtrType*));
 
 #pragma	varargck	argpos	runtime·printf	1