all: merge default branch into dev.garbage

hg was unable to create a CL on the code review server for this,
so I am submitting the merge by hand.
The only manual edits are in mgc0.c, to reapply the
removal of cached/ncached to the new code.

104 files changed, 1810 insertions, 831 deletions

diff --git a/src/cmd/5a/lex.c b/src/cmd/5a/lex.c
index 84a17d155..9c6970947 100644
--- a/src/cmd/5a/lex.c
+++ b/src/cmd/5a/lex.c
@@ -85,6 +85,7 @@ main(int argc, char *argv[])
 	ctxt = linknew(&linkarm);
 	ctxt->diag = yyerror;
 	ctxt->bso = &bstdout;
+	ctxt->enforce_data_order = 1;
 	Binit(&bstdout, 1, OWRITE);
 	listinit5();
 	fmtinstall('L', Lconv);
diff --git a/src/cmd/5c/reg.c b/src/cmd/5c/reg.c
index 2fbe031f4..9024d5f49 100644
--- a/src/cmd/5c/reg.c
+++ b/src/cmd/5c/reg.c
@@ -406,7 +406,7 @@ loop2:
 			rgp->cost = change;
 			nregion++;
 			if(nregion >= NRGN) {
-				warn(Z, "too many regions");
+				fatal(Z, "too many regions");
 				goto brk;
 			}
 			rgp++;
@@ -642,11 +642,8 @@ mkvar(Addr *a, int docon)
 	if(s)
 		if(s->name[0] == '.')
 			goto none;
-	if(nvar >= NVAR) {
-		if(debug['w'] > 1 && s)
-			warn(Z, "variable not optimized: %s", s->name);
-		goto none;
-	}
+	if(nvar >= NVAR)
+		fatal(Z, "variable not optimized: %s", s->name);
 	i = nvar;
 	nvar++;
 	v = &var[i];
diff --git a/src/cmd/6a/lex.c b/src/cmd/6a/lex.c
index b50e1622e..8973d6974 100644
--- a/src/cmd/6a/lex.c
+++ b/src/cmd/6a/lex.c
@@ -101,6 +101,7 @@ main(int argc, char *argv[])
 	ctxt = linknew(thelinkarch);
 	ctxt->diag = yyerror;
 	ctxt->bso = &bstdout;
+	ctxt->enforce_data_order = 1;
 	Binit(&bstdout, 1, OWRITE);
 	listinit6();
 	fmtinstall('L', Lconv);
diff --git a/src/cmd/6c/reg.c b/src/cmd/6c/reg.c
index 348d747b7..6f8d3ce14 100644
--- a/src/cmd/6c/reg.c
+++ b/src/cmd/6c/reg.c
@@ -585,14 +585,11 @@ loop2:
 			}
 			rgp->cost = change;
 			nregion++;
-			if(nregion >= NRGN) {
-				warn(Z, "too many regions");
-				goto brk;
-			}
+			if(nregion >= NRGN)
+				fatal(Z, "too many regions");
 			rgp++;
 		}
 	}
-brk:
 	qsort(region, nregion, sizeof(region[0]), rcmp);
 
 	/*
@@ -808,11 +805,8 @@ mkvar(Reg *r, Addr *a)
 			goto out;
 		v++;
 	}
-	if(nvar >= NVAR) {
-		if(debug['w'] > 1 && s)
-			warn(Z, "variable not optimized: %s", s->name);
-		goto none;
-	}
+	if(nvar >= NVAR)
+		fatal(Z, "variable not optimized: %s", s->name);
 	i = nvar;
 	nvar++;
 	v = &var[i];
diff --git a/src/cmd/8a/lex.c b/src/cmd/8a/lex.c
index 807e48cb5..6ce6a18ab 100644
--- a/src/cmd/8a/lex.c
+++ b/src/cmd/8a/lex.c
@@ -90,6 +90,7 @@ main(int argc, char *argv[])
 	ctxt = linknew(&link386);
 	ctxt->diag = yyerror;
 	ctxt->bso = &bstdout;
+	ctxt->enforce_data_order = 1;
 	Binit(&bstdout, 1, OWRITE);
 	listinit8();
 	fmtinstall('L', Lconv);
diff --git a/src/cmd/8c/reg.c b/src/cmd/8c/reg.c
index e6ba8bcb3..ea862f388 100644
--- a/src/cmd/8c/reg.c
+++ b/src/cmd/8c/reg.c
@@ -518,7 +518,7 @@ loop2:
 			rgp->cost = change;
 			nregion++;
 			if(nregion >= NRGN) {
-				warn(Z, "too many regions");
+				fatal(Z, "too many regions");
 				goto brk;
 			}
 			rgp++;
@@ -746,11 +746,8 @@ mkvar(Reg *r, Addr *a)
 			goto out;
 		v++;
 	}
-	if(nvar >= NVAR) {
-		if(debug['w'] > 1 && s)
-			warn(Z, "variable not optimized: %s", s->name);
-		goto none;
-	}
+	if(nvar >= NVAR)
+		fatal(Z, "variable not optimized: %s", s->name);
 	i = nvar;
 	nvar++;
 	v = &var[i];
diff --git a/src/cmd/cc/godefs.c b/src/cmd/cc/godefs.c
index d3ab52fde..d9f67f0ae 100644
--- a/src/cmd/cc/godefs.c
+++ b/src/cmd/cc/godefs.c
@@ -353,8 +353,10 @@ godefvar(Sym *s)
 		case CSTATIC:
 		case CEXTERN:
 		case CGLOBL:
-			if(strchr(s->name, '$') != nil)	 // TODO(lvd)
-			    break;
+			if(strchr(s->name, '$') != nil)
+				break;
+			if(strncmp(s->name, "go.weak.", 8) == 0)
+				break;
 			Bprint(&outbuf, "var %U\t", s->name);
 			printtypename(t);
 			Bprint(&outbuf, "\n");
diff --git a/src/cmd/gc/builtin.c b/src/cmd/gc/builtin.c
index ee1ac1da4..5fbb4f0cf 100644
--- a/src/cmd/gc/builtin.c
+++ b/src/cmd/gc/builtin.c
@@ -84,9 +84,12 @@ char *runtimeimport =
 	"func @\"\".chansend1 (@\"\".chanType·1 *byte, @\"\".hchan·2 chan<- any, @\"\".elem·3 *any)\n"
 	"func @\"\".closechan (@\"\".hchan·1 any)\n"
 	"func @\"\".writebarrierptr (@\"\".dst·1 *any, @\"\".src·2 any)\n"
-	"func @\"\".writebarrieriface (@\"\".dst·1 *any, @\"\".src·2 any)\n"
 	"func @\"\".writebarrierstring (@\"\".dst·1 *any, @\"\".src·2 any)\n"
 	"func @\"\".writebarrierslice (@\"\".dst·1 *any, @\"\".src·2 any)\n"
+	"func @\"\".writebarrieriface (@\"\".dst·1 *any, @\"\".src·2 any)\n"
+	"func @\"\".writebarrierfat2 (@\"\".dst·1 *any, _ *byte, @\"\".src·3 any)\n"
+	"func @\"\".writebarrierfat3 (@\"\".dst·1 *any, _ *byte, @\"\".src·3 any)\n"
+	"func @\"\".writebarrierfat4 (@\"\".dst·1 *any, _ *byte, @\"\".src·3 any)\n"
 	"func @\"\".writebarrierfat (@\"\".typ·1 *byte, @\"\".dst·2 *any, @\"\".src·3 *any)\n"
 	"func @\"\".selectnbsend (@\"\".chanType·2 *byte, @\"\".hchan·3 chan<- any, @\"\".elem·4 *any) (? bool)\n"
 	"func @\"\".selectnbrecv (@\"\".chanType·2 *byte, @\"\".elem·3 *any, @\"\".hchan·4 <-chan any) (? bool)\n"
diff --git a/src/cmd/gc/dcl.c b/src/cmd/gc/dcl.c
index 73c2581be..dfcf47520 100644
--- a/src/cmd/gc/dcl.c
+++ b/src/cmd/gc/dcl.c
@@ -488,6 +488,10 @@ colasdefn(NodeList *left, Node *defn)
 	NodeList *l;
 	Node *n;
 
+	for(l=left; l; l=l->next)
+		if(l->n->sym != S)
+			l->n->sym->flags |= SymUniq;
+
 	nnew = 0;
 	nerr = 0;
 	for(l=left; l; l=l->next) {
@@ -499,6 +503,13 @@ colasdefn(NodeList *left, Node *defn)
 			nerr++;
 			continue;
 		}
+		if((n->sym->flags & SymUniq) == 0) {
+			yyerrorl(defn->lineno, "%S repeated on left side of :=", n->sym);
+			n->diag++;
+			nerr++;
+			continue;
+		}
+		n->sym->flags &= ~SymUniq;
 		if(n->sym->block == block)
 			continue;
 
@@ -547,6 +558,9 @@ ifacedcl(Node *n)
 	if(n->op != ODCLFIELD || n->right == N)
 		fatal("ifacedcl");
 
+	if(isblank(n->left))
+		yyerror("methods must have a unique non-blank name");
+
 	dclcontext = PPARAM;
 	markdcl();
 	funcdepth++;
diff --git a/src/cmd/gc/order.c b/src/cmd/gc/order.c
index 3027ed27d..76820fde7 100644
--- a/src/cmd/gc/order.c
+++ b/src/cmd/gc/order.c
@@ -438,6 +438,9 @@ ordercall(Node *n, Order *order)
 // cases they are also typically registerizable, so not much harm done.
 // And this only applies to the multiple-assignment form.
 // We could do a more precise analysis if needed, like in walk.c.
+//
+// Ordermapassign also inserts these temporaries if needed for
+// calling writebarrierfat with a pointer to n->right.
 static void
 ordermapassign(Node *n, Order *order)
 {
@@ -451,7 +454,8 @@ ordermapassign(Node *n, Order *order)
 
 	case OAS:
 		order->out = list(order->out, n);
-		if((n->left->op == OINDEXMAP || (needwritebarrier(n->left, n->right) && n->left->type->width > widthptr)) && !isaddrokay(n->right)) {
+		// We call writebarrierfat only for values > 4 pointers long. See walk.c.
+		if((n->left->op == OINDEXMAP || (needwritebarrier(n->left, n->right) && n->left->type->width > 4*widthptr)) && !isaddrokay(n->right)) {
 			m = n->left;
 			n->left = ordertemp(m->type, order, 0);
 			a = nod(OAS, m, n->left);
diff --git a/src/cmd/gc/pgen.c b/src/cmd/gc/pgen.c
index 50c03788e..39028e3f8 100644
--- a/src/cmd/gc/pgen.c
+++ b/src/cmd/gc/pgen.c
@@ -182,6 +182,8 @@ compile(Node *fn)
 			yyerror("missing function body", fn);
 			goto ret;
 		}
+		if(debug['A'])
+			goto ret;
 		emitptrargsmap();
 		goto ret;
 	}
diff --git a/src/cmd/gc/racewalk.c b/src/cmd/gc/racewalk.c
index cb98ca247..c9e27fe56 100644
--- a/src/cmd/gc/racewalk.c
+++ b/src/cmd/gc/racewalk.c
@@ -210,12 +210,7 @@ racewalknode(Node **np, NodeList **init, int wr, int skip)
 	case OCALLFUNC:
 		// Instrument dst argument of runtime.writebarrier* calls
 		// as we do not instrument runtime code.
-		if(n->left->sym != S && n->left->sym->pkg == runtimepkg &&
-			(strcmp(n->left->sym->name, "writebarrierptr") == 0 ||
-			strcmp(n->left->sym->name, "writebarrierstring") == 0 ||
-			strcmp(n->left->sym->name, "writebarrierslice") == 0 ||
-			strcmp(n->left->sym->name, "writebarrieriface") == 0 ||
-			strcmp(n->left->sym->name, "writebarrierfat") == 0)) {
+		if(n->left->sym != S && n->left->sym->pkg == runtimepkg && strncmp(n->left->sym->name, "writebarrier", 12) == 0) {
 			// Find the dst argument.
 			// The list can be reordered, so it's not necessary just the first or the second element.
 			for(l = n->list; l; l = l->next) {
diff --git a/src/cmd/gc/reflect.c b/src/cmd/gc/reflect.c
index e229b3075..0f8802abc 100644
--- a/src/cmd/gc/reflect.c
+++ b/src/cmd/gc/reflect.c
@@ -716,9 +716,10 @@ static int
 dcommontype(Sym *s, int ot, Type *t)
 {
 	int i, alg, sizeofAlg, gcprog;
-	Sym *sptr, *algsym, *zero, *gcprog0, *gcprog1;
+	Sym *sptr, *algsym, *zero, *gcprog0, *gcprog1, *sbits;
 	uint8 gcmask[16];
 	static Sym *algarray;
+	uint64 x1, x2;
 	char *p;
 	
 	if(ot != 0)
@@ -804,8 +805,26 @@ dcommontype(Sym *s, int ot, Type *t)
 		ot = dsymptr(s, ot, gcprog1, 0);
 	} else {
 		gengcmask(t, gcmask);
-		for(i = 0; i < 2*widthptr; i++)
-			ot = duint8(s, ot, gcmask[i]);
+		x1 = 0;
+		for(i=0; i<8; i++)
+			x1 = x1<<8 | gcmask[i];
+		if(widthptr == 4) {
+			p = smprint("gcbits.%#016llux", x1);
+		} else {
+			x2 = 0;
+			for(i=0; i<8; i++)
+				x2 = x2<<8 | gcmask[i+8];
+			p = smprint("gcbits.%#016llux%016llux", x1, x2);
+		}
+		sbits = pkglookup(p, runtimepkg);
+		if((sbits->flags & SymUniq) == 0) {
+			sbits->flags |= SymUniq;
+			for(i = 0; i < 2*widthptr; i++)
+				duint8(sbits, i, gcmask[i]);
+			ggloblsym(sbits, 2*widthptr, DUPOK|RODATA);
+		}
+		ot = dsymptr(s, ot, sbits, 0);
+		ot = duintptr(s, ot, 0);
 	}
 	p = smprint("%-uT", t);
 	//print("dcommontype: %s\n", p);
diff --git a/src/cmd/gc/runtime.go b/src/cmd/gc/runtime.go
index fa927a58a..86afe67f1 100644
--- a/src/cmd/gc/runtime.go
+++ b/src/cmd/gc/runtime.go
@@ -112,6 +112,13 @@ func writebarrierptr(dst *any, src any)
 func writebarrierstring(dst *any, src any)
 func writebarrierslice(dst *any, src any)
 func writebarrieriface(dst *any, src any)
+
+// The unused *byte argument makes sure that src is 2-pointer-aligned,
+// which is the maximum alignment on NaCl amd64p32
+// (and possibly on 32-bit systems if we start 64-bit aligning uint64s).
+func writebarrierfat2(dst *any, _ *byte, src any)
+func writebarrierfat3(dst *any, _ *byte, src any)
+func writebarrierfat4(dst *any, _ *byte, src any)
 func writebarrierfat(typ *byte, dst *any, src *any)
 
 func selectnbsend(chanType *byte, hchan chan<- any, elem *any) bool
diff --git a/src/cmd/gc/sinit.c b/src/cmd/gc/sinit.c
index 508747e5a..f050026d9 100644
--- a/src/cmd/gc/sinit.c
+++ b/src/cmd/gc/sinit.c
@@ -207,7 +207,7 @@ init2(Node *n, NodeList **out)
 	
 	if(n->op == OCLOSURE)
 		init2list(n->closure->nbody, out);
-	if(n->op == ODOTMETH)
+	if(n->op == ODOTMETH || n->op == OCALLPART)
 		init2(n->type->nname, out);
 }
 
diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index 713348c0c..241d7d74a 100644
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -2040,30 +2040,42 @@ static Node*
 applywritebarrier(Node *n, NodeList **init)
 {
 	Node *l, *r;
+	Type *t;
 
 	if(n->left && n->right && needwritebarrier(n->left, n->right)) {
+		t = n->left->type;
 		l = nod(OADDR, n->left, N);
 		l->etype = 1; // addr does not escape
-		if(n->left->type->width == widthptr) {
-			n = mkcall1(writebarrierfn("writebarrierptr", n->left->type, n->right->type), T, init,
+		if(t->width == widthptr) {
+			n = mkcall1(writebarrierfn("writebarrierptr", t, n->right->type), T, init,
 				l, n->right);
-		} else if(n->left->type->etype == TSTRING) {
-			n = mkcall1(writebarrierfn("writebarrierstring", n->left->type, n->right->type), T, init,
+		} else if(t->etype == TSTRING) {
+			n = mkcall1(writebarrierfn("writebarrierstring", t, n->right->type), T, init,
 				l, n->right);
-		} else if(isslice(n->left->type)) {
-			n = mkcall1(writebarrierfn("writebarrierslice", n->left->type, n->right->type), T, init,
+		} else if(isslice(t)) {
+			n = mkcall1(writebarrierfn("writebarrierslice", t, n->right->type), T, init,
 				l, n->right);
-		} else if(isinter(n->left->type)) {
-			n = mkcall1(writebarrierfn("writebarrieriface", n->left->type, n->right->type), T, init,
+		} else if(isinter(t)) {
+			n = mkcall1(writebarrierfn("writebarrieriface", t, n->right->type), T, init,
 				l, n->right);
+		} else if(t->width == 2*widthptr) {
+			n = mkcall1(writebarrierfn("writebarrierfat2", t, n->right->type), T, init,
+				l, nodnil(), n->right);
+		} else if(t->width == 3*widthptr) {
+			n = mkcall1(writebarrierfn("writebarrierfat3", t, n->right->type), T, init,
+				l, nodnil(), n->right);
+		} else if(t->width == 4*widthptr) {
+			n = mkcall1(writebarrierfn("writebarrierfat4", t, n->right->type), T, init,
+				l, nodnil(), n->right);
 		} else {
 			r = n->right;
 			while(r->op == OCONVNOP)
 				r = r->left;
 			r = nod(OADDR, r, N);
 			r->etype = 1; // addr does not escape
-			n = mkcall1(writebarrierfn("writebarrierfat", n->left->type, r->left->type), T, init,
-				typename(n->left->type), l, r);
+			//warnl(n->lineno, "writebarrierfat %T %N", t, r);
+			n = mkcall1(writebarrierfn("writebarrierfat", t, r->left->type), T, init,
+				typename(t), l, r);
 		}
 	}
 	return n;
diff --git a/src/cmd/go/build.go b/src/cmd/go/build.go
index 9c7b42650..49b84709e 100644
--- a/src/cmd/go/build.go
+++ b/src/cmd/go/build.go
@@ -1852,7 +1852,7 @@ func (gccgoToolchain) linker() string {
 }
 
 func (gccgoToolchain) gc(b *builder, p *Package, archive, obj string, importArgs []string, gofiles []string) (ofile string, output []byte, err error) {
-	out := p.Name + ".o"
+	out := "_go_.o"
 	ofile = obj + out
 	gcargs := []string{"-g"}
 	gcargs = append(gcargs, b.gccArchArgs()...)
diff --git a/src/cmd/go/doc.go b/src/cmd/go/doc.go
index 8e2facd04..314c69bd8 100644
--- a/src/cmd/go/doc.go
+++ b/src/cmd/go/doc.go
@@ -385,28 +385,29 @@ syntax of package template.  The default output is equivalent to -f
 '{{.ImportPath}}'. The struct being passed to the template is:
 
     type Package struct {
-        Dir        string // directory containing package sources
-        ImportPath string // import path of package in dir
-        Name       string // package name
-        Doc        string // package documentation string
-        Target     string // install path
-        Goroot     bool   // is this package in the Go root?
-        Standard   bool   // is this package part of the standard Go library?
-        Stale      bool   // would 'go install' do anything for this package?
-        Root       string // Go root or Go path dir containing this package
+        Dir           string // directory containing package sources
+        ImportPath    string // import path of package in dir
+        ImportComment string // path in import comment on package statement
+        Name          string // package name
+        Doc           string // package documentation string
+        Target        string // install path
+        Goroot        bool   // is this package in the Go root?
+        Standard      bool   // is this package part of the standard Go library?
+        Stale         bool   // would 'go install' do anything for this package?
+        Root          string // Go root or Go path dir containing this package
 
         // Source files
-        GoFiles  []string       // .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles)
-        CgoFiles []string       // .go sources files that import "C"
+        GoFiles        []string // .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles)
+        CgoFiles       []string // .go sources files that import "C"
         IgnoredGoFiles []string // .go sources ignored due to build constraints
-        CFiles   []string       // .c source files
-        CXXFiles []string       // .cc, .cxx and .cpp source files
-        MFiles   []string       // .m source files
-        HFiles   []string       // .h, .hh, .hpp and .hxx source files
-        SFiles   []string       // .s source files
-        SwigFiles []string      // .swig files
-        SwigCXXFiles []string   // .swigcxx files
-        SysoFiles []string      // .syso object files to add to archive
+        CFiles         []string // .c source files
+        CXXFiles       []string // .cc, .cxx and .cpp source files
+        MFiles         []string // .m source files
+        HFiles         []string // .h, .hh, .hpp and .hxx source files
+        SFiles         []string // .s source files
+        SwigFiles      []string // .swig files
+        SwigCXXFiles   []string // .swigcxx files
+        SysoFiles      []string // .syso object files to add to archive
 
         // Cgo directives
         CgoCFLAGS    []string // cgo: flags for C compiler
diff --git a/src/cmd/go/list.go b/src/cmd/go/list.go
index 0ead43502..fbf96167f 100644
--- a/src/cmd/go/list.go
+++ b/src/cmd/go/list.go
@@ -30,28 +30,29 @@ syntax of package template.  The default output is equivalent to -f
 '{{.ImportPath}}'. The struct being passed to the template is:
 
     type Package struct {
-        Dir        string // directory containing package sources
-        ImportPath string // import path of package in dir
-        Name       string // package name
-        Doc        string // package documentation string
-        Target     string // install path
-        Goroot     bool   // is this package in the Go root?
-        Standard   bool   // is this package part of the standard Go library?
-        Stale      bool   // would 'go install' do anything for this package?
-        Root       string // Go root or Go path dir containing this package
+        Dir           string // directory containing package sources
+        ImportPath    string // import path of package in dir
+        ImportComment string // path in import comment on package statement
+        Name          string // package name
+        Doc           string // package documentation string
+        Target        string // install path
+        Goroot        bool   // is this package in the Go root?
+        Standard      bool   // is this package part of the standard Go library?
+        Stale         bool   // would 'go install' do anything for this package?
+        Root          string // Go root or Go path dir containing this package
 
         // Source files
-        GoFiles  []string       // .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles)
-        CgoFiles []string       // .go sources files that import "C"
+        GoFiles        []string // .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles)
+        CgoFiles       []string // .go sources files that import "C"
         IgnoredGoFiles []string // .go sources ignored due to build constraints
-        CFiles   []string       // .c source files
-        CXXFiles []string       // .cc, .cxx and .cpp source files
-        MFiles   []string       // .m source files
-        HFiles   []string       // .h, .hh, .hpp and .hxx source files
-        SFiles   []string       // .s source files
-        SwigFiles []string      // .swig files
-        SwigCXXFiles []string   // .swigcxx files
-        SysoFiles []string      // .syso object files to add to archive
+        CFiles         []string // .c source files
+        CXXFiles       []string // .cc, .cxx and .cpp source files
+        MFiles         []string // .m source files
+        HFiles         []string // .h, .hh, .hpp and .hxx source files
+        SFiles         []string // .s source files
+        SwigFiles      []string // .swig files
+        SwigCXXFiles   []string // .swigcxx files
+        SysoFiles      []string // .syso object files to add to archive
 
         // Cgo directives
         CgoCFLAGS    []string // cgo: flags for C compiler
diff --git a/src/cmd/go/pkg.go b/src/cmd/go/pkg.go
index 7f7a3b04f..e17326442 100644
--- a/src/cmd/go/pkg.go
+++ b/src/cmd/go/pkg.go
@@ -26,16 +26,17 @@ type Package struct {
 	// Note: These fields are part of the go command's public API.
 	// See list.go.  It is okay to add fields, but not to change or
 	// remove existing ones.  Keep in sync with list.go
-	Dir         string `json:",omitempty"` // directory containing package sources
-	ImportPath  string `json:",omitempty"` // import path of package in dir
-	Name        string `json:",omitempty"` // package name
-	Doc         string `json:",omitempty"` // package documentation string
-	Target      string `json:",omitempty"` // install path
-	Goroot      bool   `json:",omitempty"` // is this package found in the Go root?
-	Standard    bool   `json:",omitempty"` // is this package part of the standard Go library?
-	Stale       bool   `json:",omitempty"` // would 'go install' do anything for this package?
-	Root        string `json:",omitempty"` // Go root or Go path dir containing this package
-	ConflictDir string `json:",omitempty"` // Dir is hidden by this other directory
+	Dir           string `json:",omitempty"` // directory containing package sources
+	ImportPath    string `json:",omitempty"` // import path of package in dir
+	ImportComment string `json:",omitempty"` // path in import comment on package statement
+	Name          string `json:",omitempty"` // package name
+	Doc           string `json:",omitempty"` // package documentation string
+	Target        string `json:",omitempty"` // install path
+	Goroot        bool   `json:",omitempty"` // is this package found in the Go root?
+	Standard      bool   `json:",omitempty"` // is this package part of the standard Go library?
+	Stale         bool   `json:",omitempty"` // would 'go install' do anything for this package?
+	Root          string `json:",omitempty"` // Go root or Go path dir containing this package
+	ConflictDir   string `json:",omitempty"` // Dir is hidden by this other directory
 
 	// Source files
 	GoFiles        []string `json:",omitempty"` // .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles)
@@ -104,6 +105,7 @@ func (p *Package) copyBuild(pp *build.Package) {
 
 	p.Dir = pp.Dir
 	p.ImportPath = pp.ImportPath
+	p.ImportComment = pp.ImportComment
 	p.Name = pp.Name
 	p.Doc = pp.Doc
 	p.Root = pp.Root
diff --git a/src/cmd/go/test.bash b/src/cmd/go/test.bash
index 6a72bcde0..652ef3b5b 100755
--- a/src/cmd/go/test.bash
+++ b/src/cmd/go/test.bash
@@ -1085,6 +1085,20 @@ fi
 unset GOPATH
 rm -rf $d
 
+TEST go vet with external tests
+d=$(mktemp -d -t testgoXXX)
+export GOPATH=$(pwd)/testdata
+if ./testgo vet vetpkg >$d/err 2>&1; then
+	echo "go vet vetpkg passes incorrectly"
+	ok=false
+elif ! grep -q 'missing argument for Printf' $d/err; then
+	echo "go vet vetpkg did not find missing argument for Printf"
+	cat $d/err
+	ok=false
+fi
+unset GOPATH
+rm -rf $d
+
 # clean up
 if $started; then stop; fi
 rm -rf testdata/bin testdata/bin1
diff --git a/src/cmd/go/testdata/src/vetpkg/a_test.go b/src/cmd/go/testdata/src/vetpkg/a_test.go
new file mode 100644
index 000000000..9b64e8e1a
--- /dev/null
+++ b/src/cmd/go/testdata/src/vetpkg/a_test.go
@@ -0,0 +1 @@
+package p_test
diff --git a/src/cmd/go/testdata/src/vetpkg/b.go b/src/cmd/go/testdata/src/vetpkg/b.go
new file mode 100644
index 000000000..99e18f63d
--- /dev/null
+++ b/src/cmd/go/testdata/src/vetpkg/b.go
@@ -0,0 +1,7 @@
+package p
+
+import "fmt"
+
+func f() {
+	fmt.Printf("%d")
+}
diff --git a/src/cmd/go/vet.go b/src/cmd/go/vet.go
index ffb431837..de7befc61 100644
--- a/src/cmd/go/vet.go
+++ b/src/cmd/go/vet.go
@@ -4,6 +4,8 @@
 
 package main
 
+import "path/filepath"
+
 func init() {
 	addBuildFlagsNX(cmdVet)
 }
@@ -28,10 +30,21 @@ See also: go fmt, go fix.
 }
 
 func runVet(cmd *Command, args []string) {
-	for _, pkg := range packages(args) {
-		// Use pkg.gofiles instead of pkg.Dir so that
-		// the command only applies to this package,
-		// not to packages in subdirectories.
-		run(tool("vet"), relPaths(stringList(pkg.gofiles, pkg.sfiles)))
+	for _, p := range packages(args) {
+		// Vet expects to be given a set of files all from the same package.
+		// Run once for package p and once for package p_test.
+		if len(p.GoFiles)+len(p.CgoFiles)+len(p.TestGoFiles) > 0 {
+			runVetFiles(p, stringList(p.GoFiles, p.CgoFiles, p.TestGoFiles, p.SFiles))
+		}
+		if len(p.XTestGoFiles) > 0 {
+			runVetFiles(p, stringList(p.XTestGoFiles))
+		}
+	}
+}
+
+func runVetFiles(p *Package, files []string) {
+	for i := range files {
+		files[i] = filepath.Join(p.Dir, files[i])
 	}
+	run(tool("vet"), relPaths(files))
 }
diff --git a/src/cmd/ld/decodesym.c b/src/cmd/ld/decodesym.c
index c53066942..037263dce 100644
--- a/src/cmd/ld/decodesym.c
+++ b/src/cmd/ld/decodesym.c
@@ -111,7 +111,10 @@ decodetype_gcprog(LSym *s)
 uint8*
 decodetype_gcmask(LSym *s)
 {
-	return (uint8*)(s->p + 1*PtrSize + 8 + 1*PtrSize);
+	LSym *mask;
+	
+	mask = decode_reloc_sym(s, 1*PtrSize + 8 + 1*PtrSize);
+	return mask->p;
 }
 
 // Type.ArrayType.elem and Type.SliceType.Elem
diff --git a/src/cmd/ld/dwarf.c b/src/cmd/ld/dwarf.c
index 4efb0ed53..a3ba52325 100644
--- a/src/cmd/ld/dwarf.c
+++ b/src/cmd/ld/dwarf.c
@@ -1733,6 +1733,7 @@ writeframes(void)
 	LSym *s;
 	vlong fdeo, fdesize, pad;
 	Pciter pcsp;
+	uint32 nextpc;
 
 	if(framesec == S)
 		framesec = linklookup(ctxt, ".dwarfframe", 0);
@@ -1775,8 +1776,17 @@ writeframes(void)
 		addrput(0);	// initial location
 		addrput(0);	// address range
 
-		for(pciterinit(ctxt, &pcsp, &s->pcln->pcsp); !pcsp.done; pciternext(&pcsp))
-			putpccfadelta(pcsp.nextpc - pcsp.pc, PtrSize + pcsp.value);
+		for(pciterinit(ctxt, &pcsp, &s->pcln->pcsp); !pcsp.done; pciternext(&pcsp)) {
+			nextpc = pcsp.nextpc;
+			// pciterinit goes up to the end of the function,
+			// but DWARF expects us to stop just before the end.
+			if(nextpc == s->size) {
+				nextpc--;
+				if(nextpc < pcsp.pc)
+					continue;
+			}
+			putpccfadelta(nextpc - pcsp.pc, PtrSize + pcsp.value);
+		}
 
 		fdesize = cpos() - fdeo - 4;	// exclude the length field.
 		pad = rnd(fdesize, PtrSize) - fdesize;
diff --git a/src/cmd/ld/ldelf.c b/src/cmd/ld/ldelf.c
index 38e414755..35f8b4985 100644
--- a/src/cmd/ld/ldelf.c
+++ b/src/cmd/ld/ldelf.c
@@ -582,6 +582,8 @@ ldelf(Biobuf *f, char *pkg, int64 len, char *pn)
 			continue;
 		sect = obj->sect+sym.shndx;
 		if(sect->sym == nil) {
+			if(strncmp(sym.name, ".Linfo_string", 13) == 0) // clang does this
+				continue;
 			diag("%s: sym#%d: ignoring %s in section %d (type %d)", pn, i, sym.name, sym.shndx, sym.type);
 			continue;
 		}
diff --git a/src/cmd/ld/ldpe.c b/src/cmd/ld/ldpe.c
index 1b0591614..4f5e51f2f 100644
--- a/src/cmd/ld/ldpe.c
+++ b/src/cmd/ld/ldpe.c
@@ -128,6 +128,7 @@ struct PeObj {
 };
 
 static int map(PeObj *obj, PeSect *sect);
+static int issect(PeSym *s);
 static int readsym(PeObj *obj, int i, PeSym **sym);
 
 void
@@ -179,6 +180,15 @@ ldpe(Biobuf *f, char *pkg, int64 len, char *pn)
 	Bseek(f, base+obj->fh.PointerToSymbolTable+sizeof(symbuf)*obj->fh.NumberOfSymbols, 0);
 	if(Bread(f, obj->snames, l) != l)
 		goto bad;
+	// rewrite section names if they start with /
+	for(i=0; i < obj->fh.NumberOfSections; i++) {
+		if(obj->sect[i].name == nil)
+			continue;
+		if(obj->sect[i].name[0] != '/')
+			continue;
+		l = atoi(obj->sect[i].name + 1);
+		obj->sect[i].name = (char*)&obj->snames[l];
+	}
 	// read symbols
 	obj->pesym = mal(obj->fh.NumberOfSymbols*sizeof obj->pesym[0]);
 	obj->npesym = obj->fh.NumberOfSymbols;
@@ -309,8 +319,8 @@ ldpe(Biobuf *f, char *pkg, int64 len, char *pn)
 			// ld -r could generate multiple section symbols for the
 			// same section but with different values, we have to take
 			// that into account
-			if (obj->pesym[symindex].name[0] == '.')
-					rp->add += obj->pesym[symindex].value;
+			if(issect(&obj->pesym[symindex]))
+				rp->add += obj->pesym[symindex].value;
 		}
 		qsort(r, rsect->sh.NumberOfRelocations, sizeof r[0], rbyoff);
 		
@@ -318,12 +328,12 @@ ldpe(Biobuf *f, char *pkg, int64 len, char *pn)
 		s->r = r;
 		s->nr = rsect->sh.NumberOfRelocations;
 	}
-	
+
 	// enter sub-symbols into symbol table.
 	for(i=0; i<obj->npesym; i++) {
 		if(obj->pesym[i].name == 0)
 			continue;
-		if(obj->pesym[i].name[0] == '.') //skip section
+		if(issect(&obj->pesym[i]))
 			continue;
 		if(obj->pesym[i].sectnum > 0) {
 			sect = &obj->sect[obj->pesym[i].sectnum-1];
@@ -422,6 +432,12 @@ map(PeObj *obj, PeSect *sect)
 }
 
 static int
+issect(PeSym *s)
+{
+	return s->sclass == IMAGE_SYM_CLASS_STATIC && s->type == 0 && s->name[0] == '.';
+}
+
+static int
 readsym(PeObj *obj, int i, PeSym **y)
 {
 	LSym *s;
@@ -436,7 +452,7 @@ readsym(PeObj *obj, int i, PeSym **y)
 	sym = &obj->pesym[i];
 	*y = sym;
 	
-	if(sym->name[0] == '.') // .section
+	if(issect(sym))
 		name = obj->sect[sym->sectnum-1].sym->name;
 	else {
 		name = sym->name;
diff --git a/src/cmd/ld/macho.c b/src/cmd/ld/macho.c
index 61306bb7c..fe7e10e46 100644
--- a/src/cmd/ld/macho.c
+++ b/src/cmd/ld/macho.c
@@ -590,8 +590,7 @@ machosymtab(void)
 		if(strstr(s->extname, "·") == nil) {
 			addstring(symstr, s->extname);
 		} else {
-			p = s->extname;
-			while (*p++ != '\0') {
+			for(p = s->extname; *p; p++) {
 				if((uchar)*p == 0xc2 && (uchar)*(p+1) == 0xb7) {
 					adduint8(ctxt, symstr, '.');
 					p++;
diff --git a/src/crypto/x509/x509.go b/src/crypto/x509/x509.go
index 6e57e913a..7a37b98e3 100644
--- a/src/crypto/x509/x509.go
+++ b/src/crypto/x509/x509.go
@@ -494,6 +494,11 @@ type Certificate struct {
 	BasicConstraintsValid bool // if true then the next two fields are valid.
 	IsCA                  bool
 	MaxPathLen            int
+	// MaxPathLenZero indicates that BasicConstraintsValid==true and
+	// MaxPathLen==0 should be interpreted as an actual maximum path length
+	// of zero. Otherwise, that combination is interpreted as MaxPathLen
+	// not being set.
+	MaxPathLenZero bool
 
 	SubjectKeyId   []byte
 	AuthorityKeyId []byte
@@ -913,6 +918,7 @@ func parseCertificate(in *certificate) (*Certificate, error) {
 					out.BasicConstraintsValid = true
 					out.IsCA = constraints.IsCA
 					out.MaxPathLen = constraints.MaxPathLen
+					out.MaxPathLenZero = out.MaxPathLen == 0
 					continue
 				}
 			case 17:
@@ -1227,8 +1233,15 @@ func buildExtensions(template *Certificate) (ret []pkix.Extension, err error) {
 	}
 
 	if template.BasicConstraintsValid && !oidInExtensions(oidExtensionBasicConstraints, template.ExtraExtensions) {
+		// Leaving MaxPathLen as zero indicates that no maximum path
+		// length is desired, unless MaxPathLenZero is set. A value of
+		// -1 causes encoding/asn1 to omit the value as desired.
+		maxPathLen := template.MaxPathLen
+		if maxPathLen == 0 && !template.MaxPathLenZero {
+			maxPathLen = -1
+		}
 		ret[n].Id = oidExtensionBasicConstraints
-		ret[n].Value, err = asn1.Marshal(basicConstraints{template.IsCA, template.MaxPathLen})
+		ret[n].Value, err = asn1.Marshal(basicConstraints{template.IsCA, maxPathLen})
 		ret[n].Critical = true
 		if err != nil {
 			return
@@ -1657,7 +1670,7 @@ var oidExtensionRequest = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 9, 14}
 
 // CreateCertificateRequest creates a new certificate based on a template. The
 // following members of template are used: Subject, Attributes,
-// SignatureAlgorithm, Extension, DNSNames, EmailAddresses, and IPAddresses.
+// SignatureAlgorithm, Extensions, DNSNames, EmailAddresses, and IPAddresses.
 // The private key is the private key of the signer.
 //
 // The returned slice is the certificate request in DER encoding.
diff --git a/src/crypto/x509/x509_test.go b/src/crypto/x509/x509_test.go
index abe86216f..4f5173fb5 100644
--- a/src/crypto/x509/x509_test.go
+++ b/src/crypto/x509/x509_test.go
@@ -953,6 +953,69 @@ func TestParseCertificateRequest(t *testing.T) {
 	}
 }
 
+func TestMaxPathLen(t *testing.T) {
+	block, _ := pem.Decode([]byte(pemPrivateKey))
+	rsaPriv, err := ParsePKCS1PrivateKey(block.Bytes)
+	if err != nil {
+		t.Fatalf("Failed to parse private key: %s", err)
+	}
+
+	template := &Certificate{
+		SerialNumber: big.NewInt(1),
+		Subject: pkix.Name{
+			CommonName: "Σ Acme Co",
+		},
+		NotBefore: time.Unix(1000, 0),
+		NotAfter:  time.Unix(100000, 0),
+
+		BasicConstraintsValid: true,
+		IsCA: true,
+	}
+
+	serialiseAndParse := func(template *Certificate) *Certificate {
+		derBytes, err := CreateCertificate(rand.Reader, template, template, &rsaPriv.PublicKey, rsaPriv)
+		if err != nil {
+			t.Fatalf("failed to create certificate: %s", err)
+			return nil
+		}
+
+		cert, err := ParseCertificate(derBytes)
+		if err != nil {
+			t.Fatalf("failed to parse certificate: %s", err)
+			return nil
+		}
+
+		return cert
+	}
+
+	cert1 := serialiseAndParse(template)
+	if m := cert1.MaxPathLen; m != -1 {
+		t.Errorf("Omitting MaxPathLen didn't turn into -1, got %d", m)
+	}
+	if cert1.MaxPathLenZero {
+		t.Errorf("Omitting MaxPathLen resulted in MaxPathLenZero")
+	}
+
+	template.MaxPathLen = 1
+	cert2 := serialiseAndParse(template)
+	if m := cert2.MaxPathLen; m != 1 {
+		t.Errorf("Setting MaxPathLen didn't work. Got %d but set 1", m)
+	}
+	if cert2.MaxPathLenZero {
+		t.Errorf("Setting MaxPathLen resulted in MaxPathLenZero")
+	}
+
+	template.MaxPathLen = 0
+	template.MaxPathLenZero = true
+	cert3 := serialiseAndParse(template)
+	if m := cert3.MaxPathLen; m != 0 {
+		t.Errorf("Setting MaxPathLenZero didn't work, got %d", m)
+	}
+	if !cert3.MaxPathLenZero {
+		t.Errorf("Setting MaxPathLen to zero didn't result in MaxPathLenZero")
+	}
+}
+
 // This CSR was generated with OpenSSL:
 //  openssl req -out CSR.csr -new -newkey rsa:2048 -nodes -keyout privateKey.key -config openssl.cnf
 //
diff --git a/src/database/sql/fakedb_test.go b/src/database/sql/fakedb_test.go
index c7db0dd77..171c322d4 100644
--- a/src/database/sql/fakedb_test.go
+++ b/src/database/sql/fakedb_test.go
@@ -10,6 +10,7 @@ import (
 	"fmt"
 	"io"
 	"log"
+	"sort"
 	"strconv"
 	"strings"
 	"sync"
@@ -126,6 +127,27 @@ func init() {
 	Register("test", fdriver)
 }
 
+func contains(list []string, y string) bool {
+	for _, x := range list {
+		if x == y {
+			return true
+		}
+	}
+	return false
+}
+
+type Dummy struct {
+	driver.Driver
+}
+
+func TestDrivers(t *testing.T) {
+	Register("invalid", Dummy{})
+	all := Drivers()
+	if len(all) < 2 || !sort.StringsAreSorted(all) || !contains(all, "test") || !contains(all, "invalid") {
+		t.Fatalf("Drivers = %v, want sorted list with at least [invalid, test]", all)
+	}
+}
+
 // Supports dsn forms:
 //    <dbname>
 //    <dbname>;<opts>  (only currently supported option is `badConn`,
diff --git a/src/database/sql/sql.go b/src/database/sql/sql.go
index 731b7a7f7..ad9179cf7 100644
--- a/src/database/sql/sql.go
+++ b/src/database/sql/sql.go
@@ -18,6 +18,7 @@ import (
 	"fmt"
 	"io"
 	"runtime"
+	"sort"
 	"sync"
 )
 
@@ -36,6 +37,16 @@ func Register(name string, driver driver.Driver) {
 	drivers[name] = driver
 }
 
+// Drivers returns a sorted list of the names of the registered drivers.
+func Drivers() []string {
+	var list []string
+	for name := range drivers {
+		list = append(list, name)
+	}
+	sort.Strings(list)
+	return list
+}
+
 // RawBytes is a byte slice that holds a reference to memory owned by
 // the database itself. After a Scan into a RawBytes, the slice is only
 // valid until the next call to Next, Scan, or Close.
diff --git a/src/debug/elf/file.go b/src/debug/elf/file.go
index c908e7a88..de8a3a24f 100644
--- a/src/debug/elf/file.go
+++ b/src/debug/elf/file.go
@@ -564,6 +564,10 @@ func (f *File) applyRelocationsAMD64(dst []byte, rels []byte) error {
 			continue
 		}
 
+		// There are relocations, so this must be a normal
+		// object file, and we only look at section symbols,
+		// so we assume that the symbol value is 0.
+
 		switch t {
 		case R_X86_64_64:
 			if rela.Off+8 >= uint64(len(dst)) || rela.Addend < 0 {
@@ -646,6 +650,10 @@ func (f *File) applyRelocationsARM64(dst []byte, rels []byte) error {
 			continue
 		}
 
+		// There are relocations, so this must be a normal
+		// object file, and we only look at section symbols,
+		// so we assume that the symbol value is 0.
+
 		switch t {
 		case R_AARCH64_ABS64:
 			if rela.Off+8 >= uint64(len(dst)) || rela.Addend < 0 {
diff --git a/src/encoding/asn1/asn1.go b/src/encoding/asn1/asn1.go
index 3aeb3dcc4..8b3d1b341 100644
--- a/src/encoding/asn1/asn1.go
+++ b/src/encoding/asn1/asn1.go
@@ -640,7 +640,7 @@ func parseField(v reflect.Value, bytes []byte, initOffset int, params fieldParam
 	// when it sees a string, so if we see a different string type on the
 	// wire, we change the universal type to match.
 	if universalTag == tagPrintableString {
-		if params.tag == nil {
+		if t.class == classUniversal {
 			switch t.tag {
 			case tagIA5String, tagGeneralString, tagT61String, tagUTF8String:
 				universalTag = t.tag
@@ -652,7 +652,7 @@ func parseField(v reflect.Value, bytes []byte, initOffset int, params fieldParam
 
 	// Special case for time: UTCTime and GeneralizedTime both map to the
 	// Go type time.Time.
-	if universalTag == tagUTCTime && params.tag == nil && t.tag == tagGeneralizedTime {
+	if universalTag == tagUTCTime && t.tag == tagGeneralizedTime && t.class == classUniversal {
 		universalTag = tagGeneralizedTime
 	}
 
diff --git a/src/encoding/asn1/asn1_test.go b/src/encoding/asn1/asn1_test.go
index b94d59d36..4e864d08a 100644
--- a/src/encoding/asn1/asn1_test.go
+++ b/src/encoding/asn1/asn1_test.go
@@ -817,3 +817,51 @@ func TestStringSlice(t *testing.T) {
 		}
 	}
 }
+
+type explicitTaggedTimeTest struct {
+	Time time.Time `asn1:"explicit,tag:0"`
+}
+
+var explicitTaggedTimeTestData = []struct {
+	in  []byte
+	out explicitTaggedTimeTest
+}{
+	{[]byte{0x30, 0x11, 0xa0, 0xf, 0x17, 0xd, '9', '1', '0', '5', '0', '6', '1', '6', '4', '5', '4', '0', 'Z'},
+		explicitTaggedTimeTest{time.Date(1991, 05, 06, 16, 45, 40, 0, time.UTC)}},
+	{[]byte{0x30, 0x17, 0xa0, 0xf, 0x18, 0x13, '2', '0', '1', '0', '0', '1', '0', '2', '0', '3', '0', '4', '0', '5', '+', '0', '6', '0', '7'},
+		explicitTaggedTimeTest{time.Date(2010, 01, 02, 03, 04, 05, 0, time.FixedZone("", 6*60*60+7*60))}},
+}
+
+func TestExplicitTaggedTime(t *testing.T) {
+	// Test that a time.Time will match either tagUTCTime or
+	// tagGeneralizedTime.
+	for i, test := range explicitTaggedTimeTestData {
+		var got explicitTaggedTimeTest
+		_, err := Unmarshal(test.in, &got)
+		if err != nil {
+			t.Errorf("Unmarshal failed at index %d %v", i, err)
+		}
+		if !got.Time.Equal(test.out.Time) {
+			t.Errorf("#%d: got %v, want %v", i, got.Time, test.out.Time)
+		}
+	}
+}
+
+type implicitTaggedTimeTest struct {
+	Time time.Time `asn1:"tag:24"`
+}
+
+func TestImplicitTaggedTime(t *testing.T) {
+	// An implicitly tagged time value, that happens to have an implicit
+	// tag equal to a GENERALIZEDTIME, should still be parsed as a UTCTime.
+	// (There's no "timeType" in fieldParameters to determine what type of
+	// time should be expected when implicitly tagged.)
+	der := []byte{0x30, 0x0f, 0x80 | 24, 0xd, '9', '1', '0', '5', '0', '6', '1', '6', '4', '5', '4', '0', 'Z'}
+	var result implicitTaggedTimeTest
+	if _, err := Unmarshal(der, &result); err != nil {
+		t.Fatalf("Error while parsing: %s", err)
+	}
+	if expected := time.Date(1991, 05, 06, 16, 45, 40, 0, time.UTC); !result.Time.Equal(expected) {
+		t.Errorf("Wrong result. Got %v, want %v", result.Time, expected)
+	}
+}
diff --git a/src/encoding/gob/encode.go b/src/encoding/gob/encode.go
index b7bf8b002..04a85410c 100644
--- a/src/encoding/gob/encode.go
+++ b/src/encoding/gob/encode.go
@@ -281,15 +281,16 @@ func (enc *Encoder) encodeStruct(b *bytes.Buffer, engine *encEngine, value refle
 		field := value.FieldByIndex(instr.index)
 		if instr.indir > 0 {
 			field = encIndirect(field, instr.indir)
-		}
-		if !valid(field) {
-			continue
+			// TODO: Is field guaranteed valid? If so we could avoid this check.
+			if !valid(field) {
+				continue
+			}
 		}
 		instr.op(instr, state, field)
 	}
 }
 
-// encodeArray encodes the array whose 0th element is at p.
+// encodeArray encodes an array.
 func (enc *Encoder) encodeArray(b *bytes.Buffer, value reflect.Value, op encOp, elemIndir int, length int) {
 	state := enc.newEncoderState(b)
 	defer enc.freeEncoderState(state)
@@ -300,6 +301,7 @@ func (enc *Encoder) encodeArray(b *bytes.Buffer, value reflect.Value, op encOp,
 		elem := value.Index(i)
 		if elemIndir > 0 {
 			elem = encIndirect(elem, elemIndir)
+			// TODO: Is elem guaranteed valid? If so we could avoid this check.
 			if !valid(elem) {
 				errorf("encodeArray: nil element")
 			}
diff --git a/src/encoding/json/decode.go b/src/encoding/json/decode.go
index 67ec37388..705bc2e17 100644
--- a/src/encoding/json/decode.go
+++ b/src/encoding/json/decode.go
@@ -173,7 +173,6 @@ type decodeState struct {
 	scan       scanner
 	nextscan   scanner // for calls to nextValue
 	savedError error
-	tempstr    string // scratch space to avoid some allocations
 	useNumber  bool
 }
 
@@ -293,6 +292,32 @@ func (d *decodeState) value(v reflect.Value) {
 	}
 }
 
+type unquotedValue struct{}
+
+// valueQuoted is like value but decodes a
+// quoted string literal or literal null into an interface value.
+// If it finds anything other than a quoted string literal or null,
+// valueQuoted returns unquotedValue{}.
+func (d *decodeState) valueQuoted() interface{} {
+	switch op := d.scanWhile(scanSkipSpace); op {
+	default:
+		d.error(errPhase)
+
+	case scanBeginArray:
+		d.array(reflect.Value{})
+
+	case scanBeginObject:
+		d.object(reflect.Value{})
+
+	case scanBeginLiteral:
+		switch v := d.literalInterface().(type) {
+		case nil, string:
+			return v
+		}
+	}
+	return unquotedValue{}
+}
+
 // indirect walks down v allocating pointers as needed,
 // until it gets to a non-pointer.
 // if it encounters an Unmarshaler, indirect stops and returns that.
@@ -444,6 +469,8 @@ func (d *decodeState) array(v reflect.Value) {
 	}
 }
 
+var nullLiteral = []byte("null")
+
 // object consumes an object from d.data[d.off-1:], decoding into the value v.
 // the first byte ('{') of the object has been read already.
 func (d *decodeState) object(v reflect.Value) {
@@ -566,9 +593,14 @@ func (d *decodeState) object(v reflect.Value) {
 
 		// Read value.
 		if destring {
-			d.value(reflect.ValueOf(&d.tempstr))
-			d.literalStore([]byte(d.tempstr), subv, true)
-			d.tempstr = "" // Zero scratch space for successive values.
+			switch qv := d.valueQuoted().(type) {
+			case nil:
+				d.literalStore(nullLiteral, subv, false)
+			case string:
+				d.literalStore([]byte(qv), subv, true)
+			default:
+				d.saveError(fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal unquoted value into %v", item, v.Type()))
+			}
 		} else {
 			d.value(subv)
 		}
diff --git a/src/encoding/json/decode_test.go b/src/encoding/json/decode_test.go
index d95657d72..7235969b9 100644
--- a/src/encoding/json/decode_test.go
+++ b/src/encoding/json/decode_test.go
@@ -1070,18 +1070,25 @@ func TestEmptyString(t *testing.T) {
 	}
 }
 
-// Test that the returned error is non-nil when trying to unmarshal null string into int, for successive ,string option
-// Issue 7046
+// Test that a null for ,string is not replaced with the previous quoted string (issue 7046).
+// It should also not be an error (issue 2540, issue 8587).
 func TestNullString(t *testing.T) {
 	type T struct {
-		A int `json:",string"`
-		B int `json:",string"`
+		A int  `json:",string"`
+		B int  `json:",string"`
+		C *int `json:",string"`
 	}
-	data := []byte(`{"A": "1", "B": null}`)
+	data := []byte(`{"A": "1", "B": null, "C": null}`)
 	var s T
+	s.B = 1
+	s.C = new(int)
+	*s.C = 2
 	err := Unmarshal(data, &s)
-	if err == nil {
-		t.Fatalf("expected error; got %v", s)
+	if err != nil {
+		t.Fatalf("Unmarshal: %v")
+	}
+	if s.B != 1 || s.C != nil {
+		t.Fatalf("after Unmarshal, s.B=%d, s.C=%p, want 1, nil", s.B, s.C)
 	}
 }
 
diff --git a/src/encoding/json/encode.go b/src/encoding/json/encode.go
index b63538c92..9b7b9d5fd 100644
--- a/src/encoding/json/encode.go
+++ b/src/encoding/json/encode.go
@@ -93,6 +93,8 @@ import (
 // as described in the next paragraph.
 // An anonymous struct field with a name given in its JSON tag is treated as
 // having that name, rather than being anonymous.
+// An anonymous struct field of interface type is treated the same as having
+// that type as its name, rather than being anonymous.
 //
 // The Go visibility rules for struct fields are amended for JSON when
 // deciding which field to marshal or unmarshal. If there are
diff --git a/src/go/build/build.go b/src/go/build/build.go
index 5e11c9b9c..7a51cf3c0 100644
--- a/src/go/build/build.go
+++ b/src/go/build/build.go
@@ -417,6 +417,19 @@ func (e *NoGoError) Error() string {
 	return "no buildable Go source files in " + e.Dir
 }
 
+// MultiplePackageError describes a directory containing
+// multiple buildable Go source files for multiple packages.
+type MultiplePackageError struct {
+	Dir      string   // directory containing files
+	Packages []string // package names found
+	Files    []string // corresponding files: Files[i] declares package Packages[i]
+}
+
+func (e *MultiplePackageError) Error() string {
+	// Error string limited to two entries for compatibility.
+	return fmt.Sprintf("found packages %s (%s) and %s (%s) in %s", e.Packages[0], e.Files[0], e.Packages[1], e.Files[1], e.Dir)
+}
+
 func nameExt(name string) string {
 	i := strings.LastIndex(name, ".")
 	if i < 0 {
@@ -675,7 +688,7 @@ Found:
 			p.Name = pkg
 			firstFile = name
 		} else if pkg != p.Name {
-			return p, fmt.Errorf("found packages %s (%s) and %s (%s) in %s", p.Name, firstFile, pkg, name, p.Dir)
+			return p, &MultiplePackageError{p.Dir, []string{firstFile, name}, []string{p.Name, pkg}}
 		}
 		if pf.Doc != nil && p.Doc == "" {
 			p.Doc = doc.Synopsis(pf.Doc.Text())
@@ -1291,6 +1304,18 @@ func (ctxt *Context) goodOSArchFile(name string, allTags map[string]bool) bool {
 	if dot := strings.Index(name, "."); dot != -1 {
 		name = name[:dot]
 	}
+
+	// Before Go 1.4, a file called "linux.go" would be equivalent to having a
+	// build tag "linux" in that file. For Go 1.4 and beyond, we require this
+	// auto-tagging to apply only to files with a non-empty prefix, so
+	// "foo_linux.go" is tagged but "linux.go" is not. This allows new operating
+	// sytems, such as android, to arrive without breaking existing code with
+	// innocuous source code in "android.go". The easiest fix: files without
+	// underscores are always included.
+	if !strings.ContainsRune(name, '_') {
+		return true
+	}
+
 	l := strings.Split(name, "_")
 	if n := len(l); n > 0 && l[n-1] == "test" {
 		l = l[:n-1]
diff --git a/src/go/build/build_test.go b/src/go/build/build_test.go
index 004010113..43d09cbd1 100644
--- a/src/go/build/build_test.go
+++ b/src/go/build/build_test.go
@@ -85,6 +85,20 @@ func TestEmptyImport(t *testing.T) {
 	}
 }
 
+func TestEmptyFolderImport(t *testing.T) {
+	_, err := Import(".", "testdata/empty", 0)
+	if _, ok := err.(*NoGoError); !ok {
+		t.Fatal(`Import("testdata/empty") did not return NoGoError.`)
+	}
+}
+
+func TestMultiplePackageImport(t *testing.T) {
+	_, err := Import(".", "testdata/multi", 0)
+	if _, ok := err.(*MultiplePackageError); !ok {
+		t.Fatal(`Import("testdata/multi") did not return MultiplePackageError.`)
+	}
+}
+
 func TestLocalDirectory(t *testing.T) {
 	cwd, err := os.Getwd()
 	if err != nil {
@@ -173,6 +187,10 @@ var matchFileTests = []struct {
 	{ctxtAndroid, "foo_linux.go", "", true},
 	{ctxtAndroid, "foo_android.go", "", true},
 	{ctxtAndroid, "foo_plan9.go", "", false},
+	{ctxtAndroid, "android.go", "", true},
+	{ctxtAndroid, "plan9.go", "", true},
+	{ctxtAndroid, "arm.s", "", true},
+	{ctxtAndroid, "amd64.s", "", true},
 }
 
 func TestMatchFile(t *testing.T) {
diff --git a/src/go/build/doc.go b/src/go/build/doc.go
index 56878f2b4..75a827bb9 100644
--- a/src/go/build/doc.go
+++ b/src/go/build/doc.go
@@ -108,12 +108,10 @@
 //	*_GOOS
 // 	*_GOARCH
 // 	*_GOOS_GOARCH
-// (example: source_windows_amd64.go) or the literals:
-//	GOOS
-// 	GOARCH
-// (example: windows.go) where GOOS and GOARCH represent any known operating
-// system and architecture values respectively, then the file is considered to
-// have an implicit build constraint requiring those terms.
+// (example: source_windows_amd64.go) where GOOS and GOARCH represent
+// any known operating system and architecture values respectively, then
+// the file is considered to have an implicit build constraint requiring
+// those terms.
 //
 // To keep a file from being considered for the build:
 //
diff --git a/src/go/build/testdata/empty/dummy b/src/go/build/testdata/empty/dummy
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/src/go/build/testdata/empty/dummy
diff --git a/src/go/build/testdata/multi/file.go b/src/go/build/testdata/multi/file.go
new file mode 100644
index 000000000..ee946eb2a
--- /dev/null
+++ b/src/go/build/testdata/multi/file.go
@@ -0,0 +1,5 @@
+// Test data - not compiled.
+
+package main
+
+func main() {}
diff --git a/src/go/build/testdata/multi/file_appengine.go b/src/go/build/testdata/multi/file_appengine.go
new file mode 100644
index 000000000..4ea31e703
--- /dev/null
+++ b/src/go/build/testdata/multi/file_appengine.go
@@ -0,0 +1,5 @@
+// Test data - not compiled.
+
+package test_package
+
+func init() {}
diff --git a/src/liblink/data.c b/src/liblink/data.c
index 4504f4171..e5efa2eb2 100644
--- a/src/liblink/data.c
+++ b/src/liblink/data.c
@@ -83,6 +83,8 @@ savedata(Link *ctxt, LSym *s, Prog *p, char *pn)
 	siz = ctxt->arch->datasize(p);
 	if(off < 0 || siz < 0 || off >= 1<<30 || siz >= 100)
 		mangle(pn);
+	if(ctxt->enforce_data_order && off < s->np)
+		ctxt->diag("data out of order (already have %d)\n%P", p);
 	symgrow(ctxt, s, off+siz);
 
 	if(p->to.type == ctxt->arch->D_FCONST) {
diff --git a/src/math/big/int.go b/src/math/big/int.go
index 3998652e9..d22e39e7c 100644
--- a/src/math/big/int.go
+++ b/src/math/big/int.go
@@ -752,15 +752,16 @@ func (z *Int) Rand(rnd *rand.Rand, n *Int) *Int {
 	return z
 }
 
-// ModInverse sets z to the multiplicative inverse of g in the group ℤ/pℤ (where
-// p is a prime) and returns z.
-func (z *Int) ModInverse(g, p *Int) *Int {
+// ModInverse sets z to the multiplicative inverse of g in the ring ℤ/nℤ
+// and returns z. If g and n are not relatively prime, the result is undefined.
+func (z *Int) ModInverse(g, n *Int) *Int {
 	var d Int
-	d.GCD(z, nil, g, p)
-	// x and y are such that g*x + p*y = d. Since p is prime, d = 1. Taking
-	// that modulo p results in g*x = 1, therefore x is the inverse element.
+	d.GCD(z, nil, g, n)
+	// x and y are such that g*x + n*y = d. Since g and n are
+	// relatively prime, d = 1. Taking that modulo n results in
+	// g*x = 1, therefore x is the inverse element.
 	if z.neg {
-		z.Add(z, p)
+		z.Add(z, n)
 	}
 	return z
 }
@@ -1016,12 +1017,12 @@ func (z *Int) UnmarshalJSON(text []byte) error {
 	return nil
 }
 
-// MarshalText implements the encoding.TextMarshaler interface
+// MarshalText implements the encoding.TextMarshaler interface.
 func (z *Int) MarshalText() (text []byte, err error) {
 	return []byte(z.String()), nil
 }
 
-// UnmarshalText implements the encoding.TextUnmarshaler interface
+// UnmarshalText implements the encoding.TextUnmarshaler interface.
 func (z *Int) UnmarshalText(text []byte) error {
 	if _, ok := z.SetString(string(text), 0); !ok {
 		return fmt.Errorf("math/big: cannot unmarshal %q into a *big.Int", text)
diff --git a/src/math/big/int_test.go b/src/math/big/int_test.go
index ec05fbb1c..6070cf325 100644
--- a/src/math/big/int_test.go
+++ b/src/math/big/int_test.go
@@ -1448,24 +1448,40 @@ func TestNot(t *testing.T) {
 
 var modInverseTests = []struct {
 	element string
-	prime   string
+	modulus string
 }{
-	{"1", "7"},
-	{"1", "13"},
+	{"1234567", "458948883992"},
 	{"239487239847", "2410312426921032588552076022197566074856950548502459942654116941958108831682612228890093858261341614673227141477904012196503648957050582631942730706805009223062734745341073406696246014589361659774041027169249453200378729434170325843778659198143763193776859869524088940195577346119843545301547043747207749969763750084308926339295559968882457872412993810129130294592999947926365264059284647209730384947211681434464714438488520940127459844288859336526896320919633919"},
 }
 
 func TestModInverse(t *testing.T) {
-	var element, prime Int
+	var element, modulus, gcd, inverse Int
 	one := NewInt(1)
 	for i, test := range modInverseTests {
 		(&element).SetString(test.element, 10)
-		(&prime).SetString(test.prime, 10)
-		inverse := new(Int).ModInverse(&element, &prime)
-		inverse.Mul(inverse, &element)
-		inverse.Mod(inverse, &prime)
-		if inverse.Cmp(one) != 0 {
-			t.Errorf("#%d: failed (e·e^(-1)=%s)", i, inverse)
+		(&modulus).SetString(test.modulus, 10)
+		(&inverse).ModInverse(&element, &modulus)
+		(&inverse).Mul(&inverse, &element)
+		(&inverse).Mod(&inverse, &modulus)
+		if (&inverse).Cmp(one) != 0 {
+			t.Errorf("#%d: failed (e·e^(-1)=%s)", i, &inverse)
+		}
+	}
+	// exhaustive test for small values
+	for n := 2; n < 100; n++ {
+		(&modulus).SetInt64(int64(n))
+		for x := 1; x < n; x++ {
+			(&element).SetInt64(int64(x))
+			(&gcd).GCD(nil, nil, &element, &modulus)
+			if (&gcd).Cmp(one) != 0 {
+				continue
+			}
+			(&inverse).ModInverse(&element, &modulus)
+			(&inverse).Mul(&inverse, &element)
+			(&inverse).Mod(&inverse, &modulus)
+			if (&inverse).Cmp(one) != 0 {
+				t.Errorf("ModInverse(%d,%d)*%d%%%d=%d, not 1", &element, &modulus, &element, &modulus, &inverse)
+			}
 		}
 	}
 }
diff --git a/src/math/big/rat.go b/src/math/big/rat.go
index e6ab0bb48..c5339fe44 100644
--- a/src/math/big/rat.go
+++ b/src/math/big/rat.go
@@ -552,6 +552,9 @@ func (z *Rat) SetString(s string) (*Rat, bool) {
 		if z.b.abs, _, err = z.b.abs.scan(strings.NewReader(s), 10); err != nil {
 			return nil, false
 		}
+		if len(z.b.abs) == 0 {
+			return nil, false
+		}
 		return z.norm(), true
 	}
 
@@ -699,12 +702,12 @@ func (z *Rat) GobDecode(buf []byte) error {
 	return nil
 }
 
-// MarshalText implements the encoding.TextMarshaler interface
+// MarshalText implements the encoding.TextMarshaler interface.
 func (r *Rat) MarshalText() (text []byte, err error) {
 	return []byte(r.RatString()), nil
 }
 
-// UnmarshalText implements the encoding.TextUnmarshaler interface
+// UnmarshalText implements the encoding.TextUnmarshaler interface.
 func (r *Rat) UnmarshalText(text []byte) error {
 	if _, ok := r.SetString(string(text)); !ok {
 		return fmt.Errorf("math/big: cannot unmarshal %q into a *big.Rat", text)
diff --git a/src/math/big/rat_test.go b/src/math/big/rat_test.go
index 598eac8cc..5dbbb3510 100644
--- a/src/math/big/rat_test.go
+++ b/src/math/big/rat_test.go
@@ -89,6 +89,7 @@ var setStringTests = []struct {
 	{"53/70893980658822810696", "53/70893980658822810696", true},
 	{"106/141787961317645621392", "53/70893980658822810696", true},
 	{"204211327800791583.81095", "4084226556015831676219/20000", true},
+	{in: "1/0", ok: false},
 }
 
 func TestRatSetString(t *testing.T) {
diff --git a/src/net/fd_windows.go b/src/net/fd_windows.go
index 6d69e0624..f3a534a1d 100644
--- a/src/net/fd_windows.go
+++ b/src/net/fd_windows.go
@@ -294,6 +294,18 @@ func (fd *netFD) init() error {
 			fd.skipSyncNotif = true
 		}
 	}
+	// Disable SIO_UDP_CONNRESET behavior.
+	// http://support.microsoft.com/kb/263823
+	switch fd.net {
+	case "udp", "udp4", "udp6":
+		ret := uint32(0)
+		flag := uint32(0)
+		size := uint32(unsafe.Sizeof(flag))
+		err := syscall.WSAIoctl(fd.sysfd, syscall.SIO_UDP_CONNRESET, (*byte)(unsafe.Pointer(&flag)), size, nil, 0, &ret, nil, 0)
+		if err != nil {
+			return os.NewSyscallError("WSAIoctl", err)
+		}
+	}
 	fd.rop.mode = 'r'
 	fd.wop.mode = 'w'
 	fd.rop.fd = fd
diff --git a/src/net/http/client.go b/src/net/http/client.go
index a5a3abe61..ce884d1f0 100644
--- a/src/net/http/client.go
+++ b/src/net/http/client.go
@@ -101,6 +101,30 @@ type RoundTripper interface {
 // return true if the string includes a port.
 func hasPort(s string) bool { return strings.LastIndex(s, ":") > strings.LastIndex(s, "]") }
 
+// refererForURL returns a referer without any authentication info or
+// an empty string if lastReq scheme is https and newReq scheme is http.
+func refererForURL(lastReq, newReq *url.URL) string {
+	// https://tools.ietf.org/html/rfc7231#section-5.5.2
+	//   "Clients SHOULD NOT include a Referer header field in a
+	//    (non-secure) HTTP request if the referring page was
+	//    transferred with a secure protocol."
+	if lastReq.Scheme == "https" && newReq.Scheme == "http" {
+		return ""
+	}
+	referer := lastReq.String()
+	if lastReq.User != nil {
+		// This is not very efficient, but is the best we can
+		// do without:
+		// - introducing a new method on URL
+		// - creating a race condition
+		// - copying the URL struct manually, which would cause
+		//   maintenance problems down the line
+		auth := lastReq.User.String() + "@"
+		referer = strings.Replace(referer, auth, "", 1)
+	}
+	return referer
+}
+
 // Used in Send to implement io.ReadCloser by bundling together the
 // bufio.Reader through which we read the response, and the underlying
 // network connection.
@@ -324,8 +348,8 @@ func (c *Client) doFollowingRedirects(ireq *Request, shouldRedirect func(int) bo
 			if len(via) > 0 {
 				// Add the Referer header.
 				lastReq := via[len(via)-1]
-				if lastReq.URL.Scheme != "https" {
-					nreq.Header.Set("Referer", lastReq.URL.String())
+				if ref := refererForURL(lastReq.URL, nreq.URL); ref != "" {
+					nreq.Header.Set("Referer", ref)
 				}
 
 				err = redirectChecker(nreq, via)
diff --git a/src/net/http/client_test.go b/src/net/http/client_test.go
index 6392c1baf..56b6563c4 100644
--- a/src/net/http/client_test.go
+++ b/src/net/http/client_test.go
@@ -1036,3 +1036,40 @@ func TestClientTrailers(t *testing.T) {
 		t.Errorf("Response trailers = %#v; want %#v", res.Trailer, want)
 	}
 }
+
+func TestReferer(t *testing.T) {
+	tests := []struct {
+		lastReq, newReq string // from -> to URLs
+		want            string
+	}{
+		// don't send user:
+		{"http://gopher@test.com", "http://link.com", "http://test.com"},
+		{"https://gopher@test.com", "https://link.com", "https://test.com"},
+
+		// don't send a user and password:
+		{"http://gopher:go@test.com", "http://link.com", "http://test.com"},
+		{"https://gopher:go@test.com", "https://link.com", "https://test.com"},
+
+		// nothing to do:
+		{"http://test.com", "http://link.com", "http://test.com"},
+		{"https://test.com", "https://link.com", "https://test.com"},
+
+		// https to http doesn't send a referer:
+		{"https://test.com", "http://link.com", ""},
+		{"https://gopher:go@test.com", "http://link.com", ""},
+	}
+	for _, tt := range tests {
+		l, err := url.Parse(tt.lastReq)
+		if err != nil {
+			t.Fatal(err)
+		}
+		n, err := url.Parse(tt.newReq)
+		if err != nil {
+			t.Fatal(err)
+		}
+		r := ExportRefererForURL(l, n)
+		if r != tt.want {
+			t.Errorf("refererForURL(%q, %q) = %q; want %q", tt.lastReq, tt.newReq, r, tt.want)
+		}
+	}
+}
diff --git a/src/net/http/export_test.go b/src/net/http/export_test.go
index a6980b538..87b6c0773 100644
--- a/src/net/http/export_test.go
+++ b/src/net/http/export_test.go
@@ -9,6 +9,7 @@ package http
 
 import (
 	"net"
+	"net/url"
 	"time"
 )
 
@@ -92,6 +93,10 @@ func ResetCachedEnvironment() {
 
 var DefaultUserAgent = defaultUserAgent
 
+func ExportRefererForURL(lastReq, newReq *url.URL) string {
+	return refererForURL(lastReq, newReq)
+}
+
 // SetPendingDialHooks sets the hooks that run before and after handling
 // pending dials.
 func SetPendingDialHooks(before, after func()) {
diff --git a/src/net/http/response_test.go b/src/net/http/response_test.go
index 2dd0fad11..06e940d9a 100644
--- a/src/net/http/response_test.go
+++ b/src/net/http/response_test.go
@@ -377,6 +377,34 @@ some body`,
 
 		"Body here\n",
 	},
+
+	// 206 Partial Content. golang.org/issue/8923
+	{
+		"HTTP/1.1 206 Partial Content\r\n" +
+			"Content-Type: text/plain; charset=utf-8\r\n" +
+			"Accept-Ranges: bytes\r\n" +
+			"Content-Range: bytes 0-5/1862\r\n" +
+			"Content-Length: 6\r\n\r\n" +
+			"foobar",
+
+		Response{
+			Status:     "206 Partial Content",
+			StatusCode: 206,
+			Proto:      "HTTP/1.1",
+			ProtoMajor: 1,
+			ProtoMinor: 1,
+			Request:    dummyReq("GET"),
+			Header: Header{
+				"Accept-Ranges":  []string{"bytes"},
+				"Content-Length": []string{"6"},
+				"Content-Type":   []string{"text/plain; charset=utf-8"},
+				"Content-Range":  []string{"bytes 0-5/1862"},
+			},
+			ContentLength: 6,
+		},
+
+		"foobar",
+	},
 }
 
 func TestReadResponse(t *testing.T) {
diff --git a/src/net/http/serve_test.go b/src/net/http/serve_test.go
index 702bffdc1..bb44ac853 100644
--- a/src/net/http/serve_test.go
+++ b/src/net/http/serve_test.go
@@ -2659,6 +2659,103 @@ func TestCloseWrite(t *testing.T) {
 	}
 }
 
+// This verifies that a handler can Flush and then Hijack.
+//
+// An similar test crashed once during development, but it was only
+// testing this tangentially and temporarily until another TODO was
+// fixed.
+//
+// So add an explicit test for this.
+func TestServerFlushAndHijack(t *testing.T) {
+	defer afterTest(t)
+	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
+		io.WriteString(w, "Hello, ")
+		w.(Flusher).Flush()
+		conn, buf, _ := w.(Hijacker).Hijack()
+		buf.WriteString("6\r\nworld!\r\n0\r\n\r\n")
+		if err := buf.Flush(); err != nil {
+			t.Error(err)
+		}
+		if err := conn.Close(); err != nil {
+			t.Error(err)
+		}
+	}))
+	defer ts.Close()
+	res, err := Get(ts.URL)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer res.Body.Close()
+	all, err := ioutil.ReadAll(res.Body)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if want := "Hello, world!"; string(all) != want {
+		t.Errorf("Got %q; want %q", all, want)
+	}
+}
+
+// golang.org/issue/8534 -- the Server shouldn't reuse a connection
+// for keep-alive after it's seen any Write error (e.g. a timeout) on
+// that net.Conn.
+//
+// To test, verify we don't timeout or see fewer unique client
+// addresses (== unique connections) than requests.
+func TestServerKeepAliveAfterWriteError(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping in -short mode")
+	}
+	defer afterTest(t)
+	const numReq = 3
+	addrc := make(chan string, numReq)
+	ts := httptest.NewUnstartedServer(HandlerFunc(func(w ResponseWriter, r *Request) {
+		addrc <- r.RemoteAddr
+		time.Sleep(500 * time.Millisecond)
+		w.(Flusher).Flush()
+	}))
+	ts.Config.WriteTimeout = 250 * time.Millisecond
+	ts.Start()
+	defer ts.Close()
+
+	errc := make(chan error, numReq)
+	go func() {
+		defer close(errc)
+		for i := 0; i < numReq; i++ {
+			res, err := Get(ts.URL)
+			if res != nil {
+				res.Body.Close()
+			}
+			errc <- err
+		}
+	}()
+
+	timeout := time.NewTimer(numReq * 2 * time.Second) // 4x overkill
+	defer timeout.Stop()
+	addrSeen := map[string]bool{}
+	numOkay := 0
+	for {
+		select {
+		case v := <-addrc:
+			addrSeen[v] = true
+		case err, ok := <-errc:
+			if !ok {
+				if len(addrSeen) != numReq {
+					t.Errorf("saw %d unique client addresses; want %d", len(addrSeen), numReq)
+				}
+				if numOkay != 0 {
+					t.Errorf("got %d successful client requests; want 0", numOkay)
+				}
+				return
+			}
+			if err == nil {
+				numOkay++
+			}
+		case <-timeout.C:
+			t.Fatal("timeout waiting for requests to complete")
+		}
+	}
+}
+
 func BenchmarkClientServer(b *testing.B) {
 	b.ReportAllocs()
 	b.StopTimer()
diff --git a/src/net/http/server.go b/src/net/http/server.go
index b5959f732..008d5aa7a 100644
--- a/src/net/http/server.go
+++ b/src/net/http/server.go
@@ -114,6 +114,8 @@ type conn struct {
 	remoteAddr string               // network address of remote side
 	server     *Server              // the Server on which the connection arrived
 	rwc        net.Conn             // i/o connection
+	w          io.Writer            // checkConnErrorWriter's copy of wrc, not zeroed on Hijack
+	werr       error                // any errors writing to w
 	sr         liveSwitchReader     // where the LimitReader reads from; usually the rwc
 	lr         *io.LimitedReader    // io.LimitReader(sr)
 	buf        *bufio.ReadWriter    // buffered(lr,rwc), reading from bufio->limitReader->sr->rwc
@@ -432,13 +434,14 @@ func (srv *Server) newConn(rwc net.Conn) (c *conn, err error) {
 	c.remoteAddr = rwc.RemoteAddr().String()
 	c.server = srv
 	c.rwc = rwc
+	c.w = rwc
 	if debugServerConnections {
 		c.rwc = newLoggingConn("server", c.rwc)
 	}
 	c.sr = liveSwitchReader{r: c.rwc}
 	c.lr = io.LimitReader(&c.sr, noLimit).(*io.LimitedReader)
 	br := newBufioReader(c.lr)
-	bw := newBufioWriterSize(c.rwc, 4<<10)
+	bw := newBufioWriterSize(checkConnErrorWriter{c}, 4<<10)
 	c.buf = bufio.NewReadWriter(br, bw)
 	return c, nil
 }
@@ -956,8 +959,10 @@ func (w *response) bodyAllowed() bool {
 // 2. (*response).w, a *bufio.Writer of bufferBeforeChunkingSize bytes
 // 3. chunkWriter.Writer (whose writeHeader finalizes Content-Length/Type)
 //    and which writes the chunk headers, if needed.
-// 4. conn.buf, a bufio.Writer of default (4kB) bytes
-// 5. the rwc, the net.Conn.
+// 4. conn.buf, a bufio.Writer of default (4kB) bytes, writing to ->
+// 5. checkConnErrorWriter{c}, which notes any non-nil error on Write
+//    and populates c.werr with it if so. but otherwise writes to:
+// 6. the rwc, the net.Conn.
 //
 // TODO(bradfitz): short-circuit some of the buffering when the
 // initial header contains both a Content-Type and Content-Length.
@@ -1027,6 +1032,12 @@ func (w *response) finishRequest() {
 		// Did not write enough. Avoid getting out of sync.
 		w.closeAfterReply = true
 	}
+
+	// There was some error writing to the underlying connection
+	// during the request, so don't re-use this conn.
+	if w.conn.werr != nil {
+		w.closeAfterReply = true
+	}
 }
 
 func (w *response) Flush() {
@@ -2068,3 +2079,18 @@ func (c *loggingConn) Close() (err error) {
 	log.Printf("%s.Close() = %v", c.name, err)
 	return
 }
+
+// checkConnErrorWriter writes to c.rwc and records any write errors to c.werr.
+// It only contains one field (and a pointer field at that), so it
+// fits in an interface value without an extra allocation.
+type checkConnErrorWriter struct {
+	c *conn
+}
+
+func (w checkConnErrorWriter) Write(p []byte) (n int, err error) {
+	n, err = w.c.w.Write(p) // c.w == c.rwc, except after a hijack, when rwc is nil.
+	if err != nil && w.c.werr == nil {
+		w.c.werr = err
+	}
+	return
+}
diff --git a/src/net/http/transport.go b/src/net/http/transport.go
index 70e574fc8..782f7cd39 100644
--- a/src/net/http/transport.go
+++ b/src/net/http/transport.go
@@ -1040,11 +1040,14 @@ func (pc *persistConn) roundTrip(req *transportRequest) (resp *Response, err err
 	}
 
 	// Ask for a compressed version if the caller didn't set their
-	// own value for Accept-Encoding. We only attempted to
+	// own value for Accept-Encoding. We only attempt to
 	// uncompress the gzip stream if we were the layer that
 	// requested it.
 	requestedGzip := false
-	if !pc.t.DisableCompression && req.Header.Get("Accept-Encoding") == "" && req.Method != "HEAD" {
+	if !pc.t.DisableCompression &&
+		req.Header.Get("Accept-Encoding") == "" &&
+		req.Header.Get("Range") == "" &&
+		req.Method != "HEAD" {
 		// Request gzip only, not deflate. Deflate is ambiguous and
 		// not as universally supported anyway.
 		// See: http://www.gzip.org/zlib/zlib_faq.html#faq38
@@ -1053,6 +1056,10 @@ func (pc *persistConn) roundTrip(req *transportRequest) (resp *Response, err err
 		// due to a bug in nginx:
 		//   http://trac.nginx.org/nginx/ticket/358
 		//   http://golang.org/issue/5522
+		//
+		// We don't request gzip if the request is for a range, since
+		// auto-decoding a portion of a gzipped document will just fail
+		// anyway. See http://golang.org/issue/8923
 		requestedGzip = true
 		req.extraHeaders().Set("Accept-Encoding", "gzip")
 	}
diff --git a/src/net/http/transport_test.go b/src/net/http/transport_test.go
index 66fcc3c7d..defa63370 100644
--- a/src/net/http/transport_test.go
+++ b/src/net/http/transport_test.go
@@ -2216,6 +2216,39 @@ func TestTransportCloseIdleConnsThenReturn(t *testing.T) {
 	wantIdle("after final put", 1)
 }
 
+// This tests that an client requesting a content range won't also
+// implicitly ask for gzip support. If they want that, they need to do it
+// on their own.
+// golang.org/issue/8923
+func TestTransportRangeAndGzip(t *testing.T) {
+	defer afterTest(t)
+	reqc := make(chan *Request, 1)
+	ts := httptest.NewServer(HandlerFunc(func(w ResponseWriter, r *Request) {
+		reqc <- r
+	}))
+	defer ts.Close()
+
+	req, _ := NewRequest("GET", ts.URL, nil)
+	req.Header.Set("Range", "bytes=7-11")
+	res, err := DefaultClient.Do(req)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	select {
+	case r := <-reqc:
+		if strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
+			t.Error("Transport advertised gzip support in the Accept header")
+		}
+		if r.Header.Get("Range") == "" {
+			t.Error("no Range in request")
+		}
+	case <-time.After(10 * time.Second):
+		t.Fatal("timeout")
+	}
+	res.Body.Close()
+}
+
 func wantBody(res *http.Response, err error, want string) error {
 	if err != nil {
 		return err
diff --git a/src/net/rpc/client.go b/src/net/rpc/client.go
index 21f79b068..d0c4a6921 100644
--- a/src/net/rpc/client.go
+++ b/src/net/rpc/client.go
@@ -41,10 +41,10 @@ type Call struct {
 type Client struct {
 	codec ClientCodec
 
-	sending sync.Mutex
+	reqMutex sync.Mutex // protects following
+	request  Request
 
 	mutex    sync.Mutex // protects following
-	request  Request
 	seq      uint64
 	pending  map[uint64]*Call
 	closing  bool // user has called Close
@@ -69,8 +69,8 @@ type ClientCodec interface {
 }
 
 func (client *Client) send(call *Call) {
-	client.sending.Lock()
-	defer client.sending.Unlock()
+	client.reqMutex.Lock()
+	defer client.reqMutex.Unlock()
 
 	// Register this call.
 	client.mutex.Lock()
@@ -146,7 +146,7 @@ func (client *Client) input() {
 		}
 	}
 	// Terminate pending calls.
-	client.sending.Lock()
+	client.reqMutex.Lock()
 	client.mutex.Lock()
 	client.shutdown = true
 	closing := client.closing
@@ -162,7 +162,7 @@ func (client *Client) input() {
 		call.done()
 	}
 	client.mutex.Unlock()
-	client.sending.Unlock()
+	client.reqMutex.Unlock()
 	if debugLog && err != io.EOF && !closing {
 		log.Println("rpc: client protocol error:", err)
 	}
diff --git a/src/net/rpc/client_test.go b/src/net/rpc/client_test.go
index bbfc1ec3a..5dd111b29 100644
--- a/src/net/rpc/client_test.go
+++ b/src/net/rpc/client_test.go
@@ -6,6 +6,10 @@ package rpc
 
 import (
 	"errors"
+	"fmt"
+	"net"
+	"runtime"
+	"strings"
 	"testing"
 )
 
@@ -34,3 +38,54 @@ func TestCloseCodec(t *testing.T) {
 		t.Error("client.Close did not close codec")
 	}
 }
+
+// Test that errors in gob shut down the connection. Issue 7689.
+
+type R struct {
+	msg []byte // Not exported, so R does not work with gob.
+}
+
+type S struct{}
+
+func (s *S) Recv(nul *struct{}, reply *R) error {
+	*reply = R{[]byte("foo")}
+	return nil
+}
+
+func TestGobError(t *testing.T) {
+	if runtime.GOOS == "plan9" {
+		t.Skip("skipping test; see http://golang.org/issue/8908")
+	}
+	defer func() {
+		err := recover()
+		if err == nil {
+			t.Fatal("no error")
+		}
+		if !strings.Contains("reading body EOF", err.(error).Error()) {
+			t.Fatal("expected `reading body EOF', got", err)
+		}
+	}()
+	Register(new(S))
+
+	listen, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		panic(err)
+	}
+	go Accept(listen)
+
+	client, err := Dial("tcp", listen.Addr().String())
+	if err != nil {
+		panic(err)
+	}
+
+	var reply Reply
+	err = client.Call("S.Recv", &struct{}{}, &reply)
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Printf("%#v\n", reply)
+	client.Close()
+
+	listen.Close()
+}
diff --git a/src/net/udp_test.go b/src/net/udp_test.go
index e1778779c..125bbca6c 100644
--- a/src/net/udp_test.go
+++ b/src/net/udp_test.go
@@ -9,6 +9,7 @@ import (
 	"runtime"
 	"strings"
 	"testing"
+	"time"
 )
 
 func TestResolveUDPAddr(t *testing.T) {
@@ -34,6 +35,46 @@ func TestResolveUDPAddr(t *testing.T) {
 	}
 }
 
+func TestReadFromUDP(t *testing.T) {
+	switch runtime.GOOS {
+	case "nacl", "plan9":
+		t.Skipf("skipping test on %q, see issue 8916", runtime.GOOS)
+	}
+
+	ra, err := ResolveUDPAddr("udp", "127.0.0.1:7")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	la, err := ResolveUDPAddr("udp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	c, err := ListenUDP("udp", la)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer c.Close()
+
+	_, err = c.WriteToUDP([]byte("a"), ra)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = c.SetDeadline(time.Now().Add(100 * time.Millisecond))
+	if err != nil {
+		t.Fatal(err)
+	}
+	b := make([]byte, 1)
+	_, _, err = c.ReadFromUDP(b)
+	if err == nil {
+		t.Fatal("ReadFromUDP should fail")
+	} else if !isTimeout(err) {
+		t.Fatal(err)
+	}
+}
+
 func TestWriteToUDP(t *testing.T) {
 	switch runtime.GOOS {
 	case "plan9":
diff --git a/src/net/url/url.go b/src/net/url/url.go
index 0b32cd7c8..f167408fa 100644
--- a/src/net/url/url.go
+++ b/src/net/url/url.go
@@ -441,6 +441,24 @@ func parseAuthority(authority string) (user *Userinfo, host string, err error) {
 }
 
 // String reassembles the URL into a valid URL string.
+// The general form of the result is one of:
+//
+//	scheme:opaque
+//	scheme://userinfo@host/path?query#fragment
+//
+// If u.Opaque is non-empty, String uses the first form;
+// otherwise it uses the second form.
+//
+// In the second form, the following rules apply:
+//	- if u.Scheme is empty, scheme: is omitted.
+//	- if u.User is nil, userinfo@ is omitted.
+//	- if u.Host is empty, host/ is omitted.
+//	- if u.Scheme and u.Host are empty and u.User is nil,
+//	   the entire scheme://userinfo@host/ is omitted.
+//	- if u.Host is non-empty and u.Path begins with a /,
+//	   the form host/path does not add its own /.
+//	- if u.RawQuery is empty, ?query is omitted.
+//	- if u.Fragment is empty, #fragment is omitted.
 func (u *URL) String() string {
 	var buf bytes.Buffer
 	if u.Scheme != "" {
diff --git a/src/os/error_plan9.go b/src/os/error_plan9.go
index 45cd74792..001cdfcf2 100644
--- a/src/os/error_plan9.go
+++ b/src/os/error_plan9.go
@@ -25,7 +25,8 @@ func isNotExist(err error) bool {
 	case *LinkError:
 		err = pe.Err
 	}
-	return contains(err.Error(), "does not exist") || contains(err.Error(), "not found") || contains(err.Error(), "has been removed")
+	return contains(err.Error(), "does not exist") || contains(err.Error(), "not found") ||
+		contains(err.Error(), "has been removed") || contains(err.Error(), "no parent")
 }
 
 func isPermission(err error) bool {
diff --git a/src/os/exec/exec.go b/src/os/exec/exec.go
index 4aded4171..72b4905d5 100644
--- a/src/os/exec/exec.go
+++ b/src/os/exec/exec.go
@@ -55,8 +55,15 @@ type Cmd struct {
 	// calling process's current directory.
 	Dir string
 
-	// Stdin specifies the process's standard input. If Stdin is
-	// nil, the process reads from the null device (os.DevNull).
+	// Stdin specifies the process's standard input.
+	// If Stdin is nil, the process reads from the null device (os.DevNull).
+	// If Stdin is an *os.File, the process's standard input is connected
+	// directly to that file.
+	// Otherwise, during the execution of the command a separate
+	// goroutine reads from Stdin and delivers that data to the command
+	// over a pipe. In this case, Wait does not complete until the goroutine
+	// stops copying, either because it has reached the end of Stdin
+	// (EOF or a read error) or because writing to the pipe returned an error.
 	Stdin io.Reader
 
 	// Stdout and Stderr specify the process's standard output and error.
diff --git a/src/os/exec_unix.go b/src/os/exec_unix.go
index 1b1e3350b..ed97f85e2 100644
--- a/src/os/exec_unix.go
+++ b/src/os/exec_unix.go
@@ -34,18 +34,26 @@ func (p *Process) wait() (ps *ProcessState, err error) {
 	return ps, nil
 }
 
+var errFinished = errors.New("os: process already finished")
+
 func (p *Process) signal(sig Signal) error {
-	if p.done() {
-		return errors.New("os: process already finished")
-	}
 	if p.Pid == -1 {
 		return errors.New("os: process already released")
 	}
+	if p.Pid == 0 {
+		return errors.New("os: process not initialized")
+	}
+	if p.done() {
+		return errFinished
+	}
 	s, ok := sig.(syscall.Signal)
 	if !ok {
 		return errors.New("os: unsupported signal type")
 	}
 	if e := syscall.Kill(p.Pid, s); e != nil {
+		if e == syscall.ESRCH {
+			return errFinished
+		}
 		return e
 	}
 	return nil
diff --git a/src/os/exec_windows.go b/src/os/exec_windows.go
index c4f3d4f85..393393b23 100644
--- a/src/os/exec_windows.go
+++ b/src/os/exec_windows.go
@@ -53,6 +53,9 @@ func terminateProcess(pid, exitcode int) error {
 }
 
 func (p *Process) signal(sig Signal) error {
+	if p.handle == uintptr(syscall.InvalidHandle) {
+		return syscall.EINVAL
+	}
 	if p.done() {
 		return errors.New("os: process already finished")
 	}
diff --git a/src/os/os_test.go b/src/os/os_test.go
index 973cc3a7b..a30a2b031 100644
--- a/src/os/os_test.go
+++ b/src/os/os_test.go
@@ -124,7 +124,22 @@ func newFile(testName string, t *testing.T) (f *File) {
 	}
 	f, err := ioutil.TempFile(dir, "_Go_"+testName)
 	if err != nil {
-		t.Fatalf("open %s: %s", testName, err)
+		t.Fatalf("TempFile %s: %s", testName, err)
+	}
+	return
+}
+
+func newDir(testName string, t *testing.T) (name string) {
+	// Use a local file system, not NFS.
+	// On Unix, override $TMPDIR in case the user
+	// has it set to an NFS-mounted directory.
+	dir := ""
+	if runtime.GOOS != "android" && runtime.GOOS != "windows" {
+		dir = "/tmp"
+	}
+	name, err := ioutil.TempDir(dir, "_Go_"+testName)
+	if err != nil {
+		t.Fatalf("TempDir %s: %s", testName, err)
 	}
 	return
 }
@@ -755,35 +770,49 @@ func TestTruncate(t *testing.T) {
 	}
 }
 
-// Use TempDir() to make sure we're on a local file system,
+// Use TempDir (via newFile) to make sure we're on a local file system,
 // so that timings are not distorted by latency and caching.
 // On NFS, timings can be off due to caching of meta-data on
 // NFS servers (Issue 848).
 func TestChtimes(t *testing.T) {
 	f := newFile("TestChtimes", t)
 	defer Remove(f.Name())
-	defer f.Close()
 
 	f.Write([]byte("hello, world\n"))
 	f.Close()
 
-	st, err := Stat(f.Name())
+	testChtimes(t, f.Name())
+}
+
+// Use TempDir (via newDir) to make sure we're on a local file system,
+// so that timings are not distorted by latency and caching.
+// On NFS, timings can be off due to caching of meta-data on
+// NFS servers (Issue 848).
+func TestChtimesDir(t *testing.T) {
+	name := newDir("TestChtimes", t)
+	defer RemoveAll(name)
+
+	testChtimes(t, name)
+}
+
+func testChtimes(t *testing.T, name string) {
+	st, err := Stat(name)
 	if err != nil {
-		t.Fatalf("Stat %s: %s", f.Name(), err)
+		t.Fatalf("Stat %s: %s", name, err)
 	}
 	preStat := st
 
 	// Move access and modification time back a second
 	at := Atime(preStat)
 	mt := preStat.ModTime()
-	err = Chtimes(f.Name(), at.Add(-time.Second), mt.Add(-time.Second))
+	err = Chtimes(name, at.Add(-time.Second), mt.Add(-time.Second))
 	if err != nil {
-		t.Fatalf("Chtimes %s: %s", f.Name(), err)
+		t.Fatalf("Chtimes %s: %s", name, err)
 	}
 
-	st, err = Stat(f.Name())
+	st, err = Stat(name)
 	if err != nil {
-		t.Fatalf("second Stat %s: %s", f.Name(), err)
+		t.Fatalf("second Stat %s: %s", name, err)
 	}
 	postStat := st
 
diff --git a/src/os/path.go b/src/os/path.go
index 24a3415b4..84a3be334 100644
--- a/src/os/path.go
+++ b/src/os/path.go
@@ -17,7 +17,7 @@ import (
 // If path is already a directory, MkdirAll does nothing
 // and returns nil.
 func MkdirAll(path string, perm FileMode) error {
-	// If path exists, stop with success or error.
+	// Fast path: if we can tell whether path is a directory or file, stop with success or error.
 	dir, err := Stat(path)
 	if err == nil {
 		if dir.IsDir() {
@@ -26,7 +26,7 @@ func MkdirAll(path string, perm FileMode) error {
 		return &PathError{"mkdir", path, syscall.ENOTDIR}
 	}
 
-	// Doesn't already exist; make sure parent does.
+	// Slow path: make sure parent exists and then call Mkdir for path.
 	i := len(path)
 	for i > 0 && IsPathSeparator(path[i-1]) { // Skip trailing path separator.
 		i--
@@ -45,7 +45,7 @@ func MkdirAll(path string, perm FileMode) error {
 		}
 	}
 
-	// Now parent exists, try to create.
+	// Parent now exists; invoke Mkdir and use its result.
 	err = Mkdir(path, perm)
 	if err != nil {
 		// Handle arguments like "foo/." by
diff --git a/src/reflect/all_test.go b/src/reflect/all_test.go
index d17ef5c5e..6bdc9be9d 100644
--- a/src/reflect/all_test.go
+++ b/src/reflect/all_test.go
@@ -1543,7 +1543,17 @@ func TestMakeFuncVariadic(t *testing.T) {
 	fv := MakeFunc(TypeOf(fn), func(in []Value) []Value { return in[1:2] })
 	ValueOf(&fn).Elem().Set(fv)
 
-	r := fv.Call([]Value{ValueOf(1), ValueOf(2), ValueOf(3)})[0].Interface().([]int)
+	r := fn(1, 2, 3)
+	if r[0] != 2 || r[1] != 3 {
+		t.Errorf("Call returned [%v, %v]; want 2, 3", r[0], r[1])
+	}
+
+	r = fn(1, []int{2, 3}...)
+	if r[0] != 2 || r[1] != 3 {
+		t.Errorf("Call returned [%v, %v]; want 2, 3", r[0], r[1])
+	}
+
+	r = fv.Call([]Value{ValueOf(1), ValueOf(2), ValueOf(3)})[0].Interface().([]int)
 	if r[0] != 2 || r[1] != 3 {
 		t.Errorf("Call returned [%v, %v]; want 2, 3", r[0], r[1])
 	}
@@ -1552,6 +1562,17 @@ func TestMakeFuncVariadic(t *testing.T) {
 	if r[0] != 2 || r[1] != 3 {
 		t.Errorf("Call returned [%v, %v]; want 2, 3", r[0], r[1])
 	}
+
+	f := fv.Interface().(func(int, ...int) []int)
+
+	r = f(1, 2, 3)
+	if r[0] != 2 || r[1] != 3 {
+		t.Errorf("Call returned [%v, %v]; want 2, 3", r[0], r[1])
+	}
+	r = f(1, []int{2, 3}...)
+	if r[0] != 2 || r[1] != 3 {
+		t.Errorf("Call returned [%v, %v]; want 2, 3", r[0], r[1])
+	}
 }
 
 type Point struct {
@@ -1569,6 +1590,24 @@ func (p Point) Dist(scale int) int {
 	return p.x*p.x*scale + p.y*p.y*scale
 }
 
+// This will be index 2.
+func (p Point) GCMethod(k int) int {
+	runtime.GC()
+	return k + p.x
+}
+
+// This will be index 3.
+func (p Point) TotalDist(points ...Point) int {
+	tot := 0
+	for _, q := range points {
+		dx := q.x - p.x
+		dy := q.y - p.y
+		tot += dx*dx + dy*dy // Should call Sqrt, but it's just a test.
+
+	}
+	return tot
+}
+
 func TestMethod(t *testing.T) {
 	// Non-curried method of type.
 	p := Point{3, 4}
@@ -1751,6 +1790,37 @@ func TestMethodValue(t *testing.T) {
 	}
 }
 
+func TestVariadicMethodValue(t *testing.T) {
+	p := Point{3, 4}
+	points := []Point{{20, 21}, {22, 23}, {24, 25}}
+	want := int64(p.TotalDist(points[0], points[1], points[2]))
+
+	// Curried method of value.
+	tfunc := TypeOf((func(...Point) int)(nil))
+	v := ValueOf(p).Method(3)
+	if tt := v.Type(); tt != tfunc {
+		t.Errorf("Variadic Method Type is %s; want %s", tt, tfunc)
+	}
+	i := ValueOf(v.Interface()).Call([]Value{ValueOf(points[0]), ValueOf(points[1]), ValueOf(points[2])})[0].Int()
+	if i != want {
+		t.Errorf("Variadic Method returned %d; want %d", i, want)
+	}
+	i = ValueOf(v.Interface()).CallSlice([]Value{ValueOf(points)})[0].Int()
+	if i != want {
+		t.Errorf("Variadic Method CallSlice returned %d; want %d", i, want)
+	}
+
+	f := v.Interface().(func(...Point) int)
+	i = int64(f(points[0], points[1], points[2]))
+	if i != want {
+		t.Errorf("Variadic Method Interface returned %d; want %d", i, want)
+	}
+	i = int64(f(points...))
+	if i != want {
+		t.Errorf("Variadic Method Interface Slice returned %d; want %d", i, want)
+	}
+}
+
 // Reflect version of $GOROOT/test/method5.go
 
 // Concrete types implementing M method.
@@ -3770,11 +3840,6 @@ func TestReflectFuncTraceback(t *testing.T) {
 	f.Call([]Value{})
 }
 
-func (p Point) GCMethod(k int) int {
-	runtime.GC()
-	return k + p.x
-}
-
 func TestReflectMethodTraceback(t *testing.T) {
 	p := Point{3, 4}
 	m := ValueOf(p).MethodByName("GCMethod")
@@ -3953,3 +4018,9 @@ func TestInvalid(t *testing.T) {
 		t.Errorf("field elem: IsValid=%v, Kind=%v, want false, Invalid", v.IsValid(), v.Kind())
 	}
 }
+
+// Issue 8917.
+func TestLargeGCProg(t *testing.T) {
+	fv := ValueOf(func([256]*byte) {})
+	fv.Call([]Value{ValueOf([256]*byte{})})
+}
diff --git a/src/reflect/makefunc.go b/src/reflect/makefunc.go
index bdb8c21d7..1072c7fab 100644
--- a/src/reflect/makefunc.go
+++ b/src/reflect/makefunc.go
@@ -60,7 +60,7 @@ func MakeFunc(typ Type, fn func(args []Value) (results []Value)) Value {
 
 	impl := &makeFuncImpl{code: code, stack: stack, typ: ftyp, fn: fn}
 
-	return Value{t, unsafe.Pointer(impl), 0, flag(Func) << flagKindShift}
+	return Value{t, unsafe.Pointer(impl), flag(Func) << flagKindShift}
 }
 
 // makeFuncStub is an assembly function that is the code half of
@@ -92,7 +92,7 @@ func makeMethodValue(op string, v Value) Value {
 	// Ignoring the flagMethod bit, v describes the receiver, not the method type.
 	fl := v.flag & (flagRO | flagAddr | flagIndir)
 	fl |= flag(v.typ.Kind()) << flagKindShift
-	rcvr := Value{v.typ, v.ptr, v.scalar, fl}
+	rcvr := Value{v.typ, v.ptr, fl}
 
 	// v.Type returns the actual type of the method value.
 	funcType := v.Type().(*rtype)
@@ -118,7 +118,7 @@ func makeMethodValue(op string, v Value) Value {
 	// but we want Interface() and other operations to fail early.
 	methodReceiver(op, fv.rcvr, fv.method)
 
-	return Value{funcType, unsafe.Pointer(fv), 0, v.flag&flagRO | flag(Func)<<flagKindShift}
+	return Value{funcType, unsafe.Pointer(fv), v.flag&flagRO | flag(Func)<<flagKindShift}
 }
 
 // methodValueCall is an assembly function that is the code half of
diff --git a/src/reflect/type.go b/src/reflect/type.go
index f099546d2..26328e74b 100644
--- a/src/reflect/type.go
+++ b/src/reflect/type.go
@@ -498,7 +498,7 @@ func (t *uncommonType) Method(i int) (m Method) {
 	mt := p.typ
 	m.Type = mt
 	fn := unsafe.Pointer(&p.tfn)
-	m.Func = Value{mt, fn, 0, fl}
+	m.Func = Value{mt, fn, fl}
 	m.Index = i
 	return
 }
@@ -1514,20 +1514,32 @@ func (gc *gcProg) appendProg(t *rtype) {
 		gc.size += t.size
 		return
 	}
-	nptr := t.size / unsafe.Sizeof(uintptr(0))
-	var prog []byte
-	if t.kind&kindGCProg != 0 {
-		// Ensure that the runtime has unrolled GC program.
-		// TODO(rsc): Do not allocate.
-		unsafe_New(t)
-		// The program is stored in t.gc[0], skip unroll flag.
-		prog = (*[1 << 30]byte)(unsafe.Pointer(t.gc[0]))[1:]
-	} else {
-		// The mask is embed directly in t.gc.
-		prog = (*[1 << 30]byte)(unsafe.Pointer(&t.gc[0]))[:]
-	}
-	for i := uintptr(0); i < nptr; i++ {
-		gc.appendWord(extractGCWord(prog, i))
+	switch t.Kind() {
+	default:
+		panic("reflect: non-pointer type marked as having pointers")
+	case Ptr, UnsafePointer, Chan, Func, Map:
+		gc.appendWord(bitsPointer)
+	case Slice:
+		gc.appendWord(bitsPointer)
+		gc.appendWord(bitsScalar)
+		gc.appendWord(bitsScalar)
+	case String:
+		gc.appendWord(bitsPointer)
+		gc.appendWord(bitsScalar)
+	case Array:
+		c := t.Len()
+		e := t.Elem().common()
+		for i := 0; i < c; i++ {
+			gc.appendProg(e)
+		}
+	case Interface:
+		gc.appendWord(bitsPointer)
+		gc.appendWord(bitsPointer)
+	case Struct:
+		c := t.NumField()
+		for i := 0; i < c; i++ {
+			gc.appendProg(t.Field(i).Type.common())
+		}
 	}
 }
 
@@ -1562,7 +1574,6 @@ func (gc *gcProg) finalize() unsafe.Pointer {
 			gc.appendWord(extractGCWord(gc.gc, i))
 		}
 	}
-	gc.gc = append([]byte{1}, gc.gc...) // prepend unroll flag
 	return unsafe.Pointer(&gc.gc[0])
 }
 
@@ -1574,9 +1585,14 @@ func (gc *gcProg) align(a uintptr) {
 	gc.size = align(gc.size, a)
 }
 
+// These constants must stay in sync with ../runtime/mgc0.h.
 const (
-	bitsScalar  = 1
-	bitsPointer = 2
+	bitsScalar    = 1
+	bitsPointer   = 2
+	bitsMultiWord = 3
+
+	bitsIface = 2
+	bitsEface = 3
 )
 
 // Make sure these routines stay in sync with ../../runtime/hashmap.go!
@@ -1619,7 +1635,6 @@ func bucketOf(ktyp, etyp *rtype) *rtype {
 	b := new(rtype)
 	b.size = gc.size
 	b.gc[0] = gc.finalize()
-	b.kind |= kindGCProg
 	s := "bucket(" + *ktyp.string + "," + *etyp.string + ")"
 	b.string = &s
 	return b
@@ -1786,7 +1801,7 @@ func funcLayout(t *rtype, rcvr *rtype) (frametype *rtype, argSize, retOffset uin
 		// Reflect uses the "interface" calling convention for
 		// methods, where receivers take one word of argument
 		// space no matter how big they actually are.
-		if !isDirectIface(rcvr) {
+		if ifaceIndir(rcvr) {
 			// we pass a pointer to the receiver.
 			gc.append(bitsPointer)
 			stack.append2(bitsPointer)
@@ -1821,7 +1836,6 @@ func funcLayout(t *rtype, rcvr *rtype) (frametype *rtype, argSize, retOffset uin
 	x := new(rtype)
 	x.size = gc.size
 	x.gc[0] = gc.finalize()
-	x.kind |= kindGCProg
 	var s string
 	if rcvr != nil {
 		s = "methodargs(" + *rcvr.string + ")(" + *t.string + ")"
@@ -1844,9 +1858,9 @@ func funcLayout(t *rtype, rcvr *rtype) (frametype *rtype, argSize, retOffset uin
 	return x, argSize, retOffset, stack
 }
 
-// isDirectIface reports whether t is stored directly in an interface value.
-func isDirectIface(t *rtype) bool {
-	return t.kind&kindDirectIface != 0
+// ifaceIndir reports whether t is stored indirectly in an interface value.
+func ifaceIndir(t *rtype) bool {
+	return t.kind&kindDirectIface == 0
 }
 
 // Layout matches runtime.BitVector (well enough).
diff --git a/src/reflect/value.go b/src/reflect/value.go
index 9c65ee270..c6e8038eb 100644
--- a/src/reflect/value.go
+++ b/src/reflect/value.go
@@ -7,11 +7,9 @@ package reflect
 import (
 	"math"
 	"runtime"
-	"strconv"
 	"unsafe"
 )
 
-const bigEndian = false // can be smarter if we find a big-endian machine
 const ptrSize = unsafe.Sizeof((*byte)(nil))
 const cannotSet = "cannot set value obtained from unexported struct field"
 
@@ -40,12 +38,6 @@ type Value struct {
 	// Valid when either flagIndir is set or typ.pointers() is true.
 	ptr unsafe.Pointer
 
-	// Non-pointer-valued data.  When the data is smaller
-	// than a word, it begins at the first byte (in the memory
-	// address sense) of this field.
-	// Valid when flagIndir is not set and typ.pointers() is false.
-	scalar uintptr
-
 	// flag holds metadata about the value.
 	// The lowest bits are flag bits:
 	//	- flagRO: obtained via unexported field, so read-only
@@ -56,7 +48,7 @@ type Value struct {
 	// This repeats typ.Kind() except for method values.
 	// The remaining 23+ bits give a method number for method values.
 	// If flag.kind() != Func, code can assume that flagMethod is unset.
-	// If !isDirectIface(typ), code can assume that flagIndir is set.
+	// If ifaceIndir(typ), code can assume that flagIndir is set.
 	flag
 
 	// A method value represents a curried method invocation
@@ -102,7 +94,7 @@ func packEface(v Value) interface{} {
 	e := (*emptyInterface)(unsafe.Pointer(&i))
 	// First, fill in the data portion of the interface.
 	switch {
-	case !isDirectIface(t):
+	case ifaceIndir(t):
 		if v.flag&flagIndir == 0 {
 			panic("bad indir")
 		}
@@ -119,18 +111,10 @@ func packEface(v Value) interface{} {
 	case v.flag&flagIndir != 0:
 		// Value is indirect, but interface is direct.  We need
 		// to load the data at v.ptr into the interface data word.
-		if t.pointers() {
-			e.word = iword(*(*unsafe.Pointer)(v.ptr))
-		} else {
-			e.word = iword(loadScalar(v.ptr, t.size))
-		}
+		e.word = iword(*(*unsafe.Pointer)(v.ptr))
 	default:
 		// Value is direct, and so is the interface.
-		if t.pointers() {
-			e.word = iword(v.ptr)
-		} else {
-			e.word = iword(v.scalar)
-		}
+		e.word = iword(v.ptr)
 	}
 	// Now, fill in the type portion.  We're very careful here not
 	// to have any operation between the e.word and e.typ assignments
@@ -149,13 +133,10 @@ func unpackEface(i interface{}) Value {
 		return Value{}
 	}
 	f := flag(t.Kind()) << flagKindShift
-	if !isDirectIface(t) {
-		return Value{t, unsafe.Pointer(e.word), 0, f | flagIndir}
-	}
-	if t.pointers() {
-		return Value{t, unsafe.Pointer(e.word), 0, f}
+	if ifaceIndir(t) {
+		f |= flagIndir
 	}
-	return Value{t, nil, uintptr(e.word), f}
+	return Value{t, unsafe.Pointer(e.word), f}
 }
 
 // A ValueError occurs when a Value method is invoked on
@@ -194,64 +175,6 @@ func methodName() string {
 // to the GC here so that GC remains precise.
 type iword unsafe.Pointer
 
-// loadScalar loads n bytes at p from memory into a uintptr
-// that forms the second word of an interface.  The data
-// must be non-pointer in nature.
-func loadScalar(p unsafe.Pointer, n uintptr) uintptr {
-	// Run the copy ourselves instead of calling memmove
-	// to avoid moving w to the heap.
-	var w uintptr
-	switch n {
-	default:
-		panic("reflect: internal error: loadScalar of " + strconv.Itoa(int(n)) + "-byte value")
-	case 0:
-	case 1:
-		*(*uint8)(unsafe.Pointer(&w)) = *(*uint8)(p)
-	case 2:
-		*(*uint16)(unsafe.Pointer(&w)) = *(*uint16)(p)
-	case 3:
-		*(*[3]byte)(unsafe.Pointer(&w)) = *(*[3]byte)(p)
-	case 4:
-		*(*uint32)(unsafe.Pointer(&w)) = *(*uint32)(p)
-	case 5:
-		*(*[5]byte)(unsafe.Pointer(&w)) = *(*[5]byte)(p)
-	case 6:
-		*(*[6]byte)(unsafe.Pointer(&w)) = *(*[6]byte)(p)
-	case 7:
-		*(*[7]byte)(unsafe.Pointer(&w)) = *(*[7]byte)(p)
-	case 8:
-		*(*uint64)(unsafe.Pointer(&w)) = *(*uint64)(p)
-	}
-	return w
-}
-
-// storeScalar stores n bytes from w into p.
-func storeScalar(p unsafe.Pointer, w uintptr, n uintptr) {
-	// Run the copy ourselves instead of calling memmove
-	// to avoid moving w to the heap.
-	switch n {
-	default:
-		panic("reflect: internal error: storeScalar of " + strconv.Itoa(int(n)) + "-byte value")
-	case 0:
-	case 1:
-		*(*uint8)(p) = *(*uint8)(unsafe.Pointer(&w))
-	case 2:
-		*(*uint16)(p) = *(*uint16)(unsafe.Pointer(&w))
-	case 3:
-		*(*[3]byte)(p) = *(*[3]byte)(unsafe.Pointer(&w))
-	case 4:
-		*(*uint32)(p) = *(*uint32)(unsafe.Pointer(&w))
-	case 5:
-		*(*[5]byte)(p) = *(*[5]byte)(unsafe.Pointer(&w))
-	case 6:
-		*(*[6]byte)(p) = *(*[6]byte)(unsafe.Pointer(&w))
-	case 7:
-		*(*[7]byte)(p) = *(*[7]byte)(unsafe.Pointer(&w))
-	case 8:
-		*(*uint64)(p) = *(*uint64)(unsafe.Pointer(&w))
-	}
-}
-
 // emptyInterface is the header for an interface{} value.
 type emptyInterface struct {
 	typ  *rtype
@@ -321,17 +244,14 @@ func (v Value) Addr() Value {
 	if v.flag&flagAddr == 0 {
 		panic("reflect.Value.Addr of unaddressable value")
 	}
-	return Value{v.typ.ptrTo(), v.ptr, 0, (v.flag & flagRO) | flag(Ptr)<<flagKindShift}
+	return Value{v.typ.ptrTo(), v.ptr, (v.flag & flagRO) | flag(Ptr)<<flagKindShift}
 }
 
 // Bool returns v's underlying value.
 // It panics if v's kind is not Bool.
 func (v Value) Bool() bool {
 	v.mustBe(Bool)
-	if v.flag&flagIndir != 0 {
-		return *(*bool)(v.ptr)
-	}
-	return *(*bool)(unsafe.Pointer(&v.scalar))
+	return *(*bool)(v.ptr)
 }
 
 // Bytes returns v's underlying value.
@@ -501,10 +421,8 @@ func (v Value) call(op string, in []Value) []Value {
 		v = v.assignTo("reflect.Value.Call", targ, (*interface{})(addr))
 		if v.flag&flagIndir != 0 {
 			memmove(addr, v.ptr, n)
-		} else if targ.pointers() {
-			*(*unsafe.Pointer)(addr) = v.ptr
 		} else {
-			storeScalar(addr, v.scalar, n)
+			*(*unsafe.Pointer)(addr) = v.ptr
 		}
 		off += n
 	}
@@ -525,7 +443,7 @@ func (v Value) call(op string, in []Value) []Value {
 		a := uintptr(tv.Align())
 		off = (off + a - 1) &^ (a - 1)
 		fl := flagIndir | flag(tv.Kind())<<flagKindShift
-		ret[i] = Value{tv.common(), unsafe.Pointer(uintptr(args) + off), 0, fl}
+		ret[i] = Value{tv.common(), unsafe.Pointer(uintptr(args) + off), fl}
 		off += tv.Size()
 	}
 
@@ -556,8 +474,8 @@ func callReflect(ctxt *makeFuncImpl, frame unsafe.Pointer) {
 		typ := arg
 		off += -off & uintptr(typ.align-1)
 		addr := unsafe.Pointer(uintptr(ptr) + off)
-		v := Value{typ, nil, 0, flag(typ.Kind()) << flagKindShift}
-		if !isDirectIface(typ) {
+		v := Value{typ, nil, flag(typ.Kind()) << flagKindShift}
+		if ifaceIndir(typ) {
 			// value cannot be inlined in interface data.
 			// Must make a copy, because f might keep a reference to it,
 			// and we cannot let f keep a reference to the stack frame
@@ -565,10 +483,8 @@ func callReflect(ctxt *makeFuncImpl, frame unsafe.Pointer) {
 			v.ptr = unsafe_New(typ)
 			memmove(v.ptr, addr, typ.size)
 			v.flag |= flagIndir
-		} else if typ.pointers() {
-			v.ptr = *(*unsafe.Pointer)(addr)
 		} else {
-			v.scalar = loadScalar(addr, typ.size)
+			v.ptr = *(*unsafe.Pointer)(addr)
 		}
 		in = append(in, v)
 		off += typ.size
@@ -602,10 +518,8 @@ func callReflect(ctxt *makeFuncImpl, frame unsafe.Pointer) {
 			addr := unsafe.Pointer(uintptr(ptr) + off)
 			if v.flag&flagIndir != 0 {
 				memmove(addr, v.ptr, typ.size)
-			} else if typ.pointers() {
-				*(*unsafe.Pointer)(addr) = v.ptr
 			} else {
-				storeScalar(addr, v.scalar, typ.size)
+				*(*unsafe.Pointer)(addr) = v.ptr
 			}
 			off += typ.size
 		}
@@ -663,18 +577,10 @@ func storeRcvr(v Value, p unsafe.Pointer) {
 		// the interface data word becomes the receiver word
 		iface := (*nonEmptyInterface)(v.ptr)
 		*(*unsafe.Pointer)(p) = unsafe.Pointer(iface.word)
-	} else if v.flag&flagIndir != 0 {
-		if !isDirectIface(t) {
-			*(*unsafe.Pointer)(p) = v.ptr
-		} else if t.pointers() {
-			*(*unsafe.Pointer)(p) = *(*unsafe.Pointer)(v.ptr)
-		} else {
-			*(*uintptr)(p) = loadScalar(v.ptr, t.size)
-		}
-	} else if t.pointers() {
-		*(*unsafe.Pointer)(p) = v.ptr
+	} else if v.flag&flagIndir != 0 && !ifaceIndir(t) {
+		*(*unsafe.Pointer)(p) = *(*unsafe.Pointer)(v.ptr)
 	} else {
-		*(*uintptr)(p) = v.scalar
+		*(*unsafe.Pointer)(p) = v.ptr
 	}
 }
 
@@ -763,12 +669,8 @@ func (v Value) Complex() complex128 {
 	k := v.kind()
 	switch k {
 	case Complex64:
-		if v.flag&flagIndir != 0 {
-			return complex128(*(*complex64)(v.ptr))
-		}
-		return complex128(*(*complex64)(unsafe.Pointer(&v.scalar)))
+		return complex128(*(*complex64)(v.ptr))
 	case Complex128:
-		// complex128 is always bigger than a word; assume flagIndir.
 		return *(*complex128)(v.ptr)
 	}
 	panic(&ValueError{"reflect.Value.Complex", k})
@@ -808,7 +710,7 @@ func (v Value) Elem() Value {
 		typ := tt.elem
 		fl := v.flag&flagRO | flagIndir | flagAddr
 		fl |= flag(typ.Kind() << flagKindShift)
-		return Value{typ, ptr, 0, fl}
+		return Value{typ, ptr, fl}
 	}
 	panic(&ValueError{"reflect.Value.Elem", k})
 }
@@ -833,30 +735,25 @@ func (v Value) Field(i int) Value {
 	fl |= flag(typ.Kind()) << flagKindShift
 
 	var ptr unsafe.Pointer
-	var scalar uintptr
-	switch {
-	case fl&flagIndir != 0:
+	if fl&flagIndir != 0 {
 		// Indirect.  Just bump pointer.
 		ptr = unsafe.Pointer(uintptr(v.ptr) + field.offset)
-	case typ.pointers():
+	} else {
 		if field.offset != 0 {
 			panic("field access of ptr value isn't at offset 0")
 		}
 		ptr = v.ptr
-	case bigEndian:
-		// Must be scalar.  Discard leading bytes.
-		scalar = v.scalar << (field.offset * 8)
-	default:
-		// Must be scalar.  Discard leading bytes.
-		scalar = v.scalar >> (field.offset * 8)
 	}
 
-	return Value{typ, ptr, scalar, fl}
+	return Value{typ, ptr, fl}
 }
 
 // FieldByIndex returns the nested field corresponding to index.
 // It panics if v's Kind is not struct.
 func (v Value) FieldByIndex(index []int) Value {
+	if len(index) == 1 {
+		return v.Field(index[0])
+	}
 	v.mustBe(Struct)
 	for i, x := range index {
 		if i > 0 {
@@ -901,15 +798,9 @@ func (v Value) Float() float64 {
 	k := v.kind()
 	switch k {
 	case Float32:
-		if v.flag&flagIndir != 0 {
-			return float64(*(*float32)(v.ptr))
-		}
-		return float64(*(*float32)(unsafe.Pointer(&v.scalar)))
+		return float64(*(*float32)(v.ptr))
 	case Float64:
-		if v.flag&flagIndir != 0 {
-			return *(*float64)(v.ptr)
-		}
-		return *(*float64)(unsafe.Pointer(&v.scalar))
+		return *(*float64)(v.ptr)
 	}
 	panic(&ValueError{"reflect.Value.Float", k})
 }
@@ -932,12 +823,10 @@ func (v Value) Index(i int) Value {
 		offset := uintptr(i) * typ.size
 
 		var val unsafe.Pointer
-		var scalar uintptr
-		switch {
-		case fl&flagIndir != 0:
+		if fl&flagIndir != 0 {
 			// Indirect.  Just bump pointer.
 			val = unsafe.Pointer(uintptr(v.ptr) + offset)
-		case typ.pointers():
+		} else {
 			if offset != 0 {
 				// This is an array stored inline in an interface value.
 				// And the array element type has pointers.
@@ -948,14 +837,8 @@ func (v Value) Index(i int) Value {
 				panic("reflect: internal error: unexpected array index")
 			}
 			val = v.ptr
-		case bigEndian:
-			// Direct.  Discard leading bytes.
-			scalar = v.scalar << (offset * 8)
-		default:
-			// Direct.  Discard leading bytes.
-			scalar = v.scalar >> (offset * 8)
 		}
-		return Value{typ, val, scalar, fl}
+		return Value{typ, val, fl}
 
 	case Slice:
 		// Element flag same as Elem of Ptr.
@@ -969,7 +852,7 @@ func (v Value) Index(i int) Value {
 		typ := tt.elem
 		fl |= flag(typ.Kind()) << flagKindShift
 		val := unsafe.Pointer(uintptr(s.Data) + uintptr(i)*typ.size)
-		return Value{typ, val, 0, fl}
+		return Value{typ, val, fl}
 
 	case String:
 		fl := v.flag&flagRO | flag(Uint8<<flagKindShift) | flagIndir
@@ -978,7 +861,7 @@ func (v Value) Index(i int) Value {
 			panic("reflect: string index out of range")
 		}
 		p := unsafe.Pointer(uintptr(s.Data) + uintptr(i))
-		return Value{uint8Type, p, 0, fl}
+		return Value{uint8Type, p, fl}
 	}
 	panic(&ValueError{"reflect.Value.Index", k})
 }
@@ -987,14 +870,7 @@ func (v Value) Index(i int) Value {
 // It panics if v's Kind is not Int, Int8, Int16, Int32, or Int64.
 func (v Value) Int() int64 {
 	k := v.kind()
-	var p unsafe.Pointer
-	if v.flag&flagIndir != 0 {
-		p = v.ptr
-	} else {
-		// The escape analysis is good enough that &v.scalar
-		// does not trigger a heap allocation.
-		p = unsafe.Pointer(&v.scalar)
-	}
+	p := v.ptr
 	switch k {
 	case Int:
 		return int64(*(*int)(p))
@@ -1154,10 +1030,8 @@ func (v Value) MapIndex(key Value) Value {
 	var k unsafe.Pointer
 	if key.flag&flagIndir != 0 {
 		k = key.ptr
-	} else if key.typ.pointers() {
-		k = unsafe.Pointer(&key.ptr)
 	} else {
-		k = unsafe.Pointer(&key.scalar)
+		k = unsafe.Pointer(&key.ptr)
 	}
 	e := mapaccess(v.typ, v.pointer(), k)
 	if e == nil {
@@ -1166,16 +1040,14 @@ func (v Value) MapIndex(key Value) Value {
 	typ := tt.elem
 	fl := (v.flag | key.flag) & flagRO
 	fl |= flag(typ.Kind()) << flagKindShift
-	if !isDirectIface(typ) {
+	if ifaceIndir(typ) {
 		// Copy result so future changes to the map
 		// won't change the underlying value.
 		c := unsafe_New(typ)
 		memmove(c, e, typ.size)
-		return Value{typ, c, 0, fl | flagIndir}
-	} else if typ.pointers() {
-		return Value{typ, *(*unsafe.Pointer)(e), 0, fl}
+		return Value{typ, c, fl | flagIndir}
 	} else {
-		return Value{typ, nil, loadScalar(e, typ.size), fl}
+		return Value{typ, *(*unsafe.Pointer)(e), fl}
 	}
 }
 
@@ -1206,16 +1078,14 @@ func (v Value) MapKeys() []Value {
 			// we can do about it.
 			break
 		}
-		if !isDirectIface(keyType) {
+		if ifaceIndir(keyType) {
 			// Copy result so future changes to the map
 			// won't change the underlying value.
 			c := unsafe_New(keyType)
 			memmove(c, key, keyType.size)
-			a[i] = Value{keyType, c, 0, fl | flagIndir}
-		} else if keyType.pointers() {
-			a[i] = Value{keyType, *(*unsafe.Pointer)(key), 0, fl}
+			a[i] = Value{keyType, c, fl | flagIndir}
 		} else {
-			a[i] = Value{keyType, nil, loadScalar(key, keyType.size), fl}
+			a[i] = Value{keyType, *(*unsafe.Pointer)(key), fl}
 		}
 		mapiternext(it)
 	}
@@ -1239,7 +1109,7 @@ func (v Value) Method(i int) Value {
 	fl := v.flag & (flagRO | flagIndir)
 	fl |= flag(Func) << flagKindShift
 	fl |= flag(i)<<flagMethodShift | flagMethod
-	return Value{v.typ, v.ptr, v.scalar, fl}
+	return Value{v.typ, v.ptr, fl}
 }
 
 // NumMethod returns the number of methods in the value's method set.
@@ -1403,16 +1273,14 @@ func (v Value) recv(nb bool) (val Value, ok bool) {
 		panic("reflect: recv on send-only channel")
 	}
 	t := tt.elem
-	val = Value{t, nil, 0, flag(t.Kind()) << flagKindShift}
+	val = Value{t, nil, flag(t.Kind()) << flagKindShift}
 	var p unsafe.Pointer
-	if !isDirectIface(t) {
+	if ifaceIndir(t) {
 		p = unsafe_New(t)
 		val.ptr = p
 		val.flag |= flagIndir
-	} else if t.pointers() {
-		p = unsafe.Pointer(&val.ptr)
 	} else {
-		p = unsafe.Pointer(&val.scalar)
+		p = unsafe.Pointer(&val.ptr)
 	}
 	selected, ok := chanrecv(v.typ, v.pointer(), nb, p)
 	if !selected {
@@ -1442,10 +1310,8 @@ func (v Value) send(x Value, nb bool) (selected bool) {
 	var p unsafe.Pointer
 	if x.flag&flagIndir != 0 {
 		p = x.ptr
-	} else if x.typ.pointers() {
-		p = unsafe.Pointer(&x.ptr)
 	} else {
-		p = unsafe.Pointer(&x.scalar)
+		p = unsafe.Pointer(&x.ptr)
 	}
 	return chansend(v.typ, v.pointer(), p, nb)
 }
@@ -1463,10 +1329,8 @@ func (v Value) Set(x Value) {
 	x = x.assignTo("reflect.Set", v.typ, target)
 	if x.flag&flagIndir != 0 {
 		memmove(v.ptr, x.ptr, v.typ.size)
-	} else if x.typ.pointers() {
-		*(*unsafe.Pointer)(v.ptr) = x.ptr
 	} else {
-		memmove(v.ptr, unsafe.Pointer(&x.scalar), v.typ.size)
+		*(*unsafe.Pointer)(v.ptr) = x.ptr
 	}
 }
 
@@ -1589,10 +1453,8 @@ func (v Value) SetMapIndex(key, val Value) {
 	var k unsafe.Pointer
 	if key.flag&flagIndir != 0 {
 		k = key.ptr
-	} else if key.typ.pointers() {
-		k = unsafe.Pointer(&key.ptr)
 	} else {
-		k = unsafe.Pointer(&key.scalar)
+		k = unsafe.Pointer(&key.ptr)
 	}
 	if val.typ == nil {
 		mapdelete(v.typ, v.pointer(), k)
@@ -1603,10 +1465,8 @@ func (v Value) SetMapIndex(key, val Value) {
 	var e unsafe.Pointer
 	if val.flag&flagIndir != 0 {
 		e = val.ptr
-	} else if val.typ.pointers() {
-		e = unsafe.Pointer(&val.ptr)
 	} else {
-		e = unsafe.Pointer(&val.scalar)
+		e = unsafe.Pointer(&val.ptr)
 	}
 	mapassign(v.typ, v.pointer(), k, e)
 }
@@ -1683,7 +1543,7 @@ func (v Value) Slice(i, j int) Value {
 			panic("reflect.Value.Slice: string slice index out of bounds")
 		}
 		t := stringHeader{unsafe.Pointer(uintptr(s.Data) + uintptr(i)), j - i}
-		return Value{v.typ, unsafe.Pointer(&t), 0, v.flag}
+		return Value{v.typ, unsafe.Pointer(&t), v.flag}
 	}
 
 	if i < 0 || j < i || j > cap {
@@ -1705,7 +1565,7 @@ func (v Value) Slice(i, j int) Value {
 	}
 
 	fl := v.flag&flagRO | flagIndir | flag(Slice)<<flagKindShift
-	return Value{typ.common(), unsafe.Pointer(&x), 0, fl}
+	return Value{typ.common(), unsafe.Pointer(&x), fl}
 }
 
 // Slice3 is the 3-index form of the slice operation: it returns v[i:j:k].
@@ -1757,7 +1617,7 @@ func (v Value) Slice3(i, j, k int) Value {
 	}
 
 	fl := v.flag&flagRO | flagIndir | flag(Slice)<<flagKindShift
-	return Value{typ.common(), unsafe.Pointer(&x), 0, fl}
+	return Value{typ.common(), unsafe.Pointer(&x), fl}
 }
 
 // String returns the string v's underlying value, as a string.
@@ -1833,14 +1693,7 @@ func (v Value) Type() Type {
 // It panics if v's Kind is not Uint, Uintptr, Uint8, Uint16, Uint32, or Uint64.
 func (v Value) Uint() uint64 {
 	k := v.kind()
-	var p unsafe.Pointer
-	if v.flag&flagIndir != 0 {
-		p = v.ptr
-	} else {
-		// The escape analysis is good enough that &v.scalar
-		// does not trigger a heap allocation.
-		p = unsafe.Pointer(&v.scalar)
-	}
+	p := v.ptr
 	switch k {
 	case Uint:
 		return uint64(*(*uint)(p))
@@ -1994,17 +1847,6 @@ func Copy(dst, src Value) int {
 		n = sn
 	}
 
-	// If sk is an in-line array, cannot take its address.
-	// Instead, copy element by element.
-	// TODO: memmove would be ok for this (sa = unsafe.Pointer(&v.scalar))
-	// if we teach the compiler that ptrs don't escape from memmove.
-	if src.flag&flagIndir == 0 {
-		for i := 0; i < n; i++ {
-			dst.Index(i).Set(src.Index(i))
-		}
-		return n
-	}
-
 	// Copy via memmove.
 	var da, sa unsafe.Pointer
 	if dk == Array {
@@ -2012,7 +1854,9 @@ func Copy(dst, src Value) int {
 	} else {
 		da = (*sliceHeader)(dst.ptr).Data
 	}
-	if sk == Array {
+	if src.flag&flagIndir == 0 {
+		sa = unsafe.Pointer(&src.ptr)
+	} else if sk == Array {
 		sa = src.ptr
 	} else {
 		sa = (*sliceHeader)(src.ptr).Data
@@ -2125,10 +1969,8 @@ func Select(cases []SelectCase) (chosen int, recv Value, recvOK bool) {
 			v = v.assignTo("reflect.Select", tt.elem, nil)
 			if v.flag&flagIndir != 0 {
 				rc.val = v.ptr
-			} else if v.typ.pointers() {
-				rc.val = unsafe.Pointer(&v.ptr)
 			} else {
-				rc.val = unsafe.Pointer(&v.scalar)
+				rc.val = unsafe.Pointer(&v.ptr)
 			}
 
 		case SelectRecv:
@@ -2157,12 +1999,10 @@ func Select(cases []SelectCase) (chosen int, recv Value, recvOK bool) {
 		t := tt.elem
 		p := runcases[chosen].val
 		fl := flag(t.Kind()) << flagKindShift
-		if !isDirectIface(t) {
-			recv = Value{t, p, 0, fl | flagIndir}
-		} else if t.pointers() {
-			recv = Value{t, *(*unsafe.Pointer)(p), 0, fl}
+		if ifaceIndir(t) {
+			recv = Value{t, p, fl | flagIndir}
 		} else {
-			recv = Value{t, nil, loadScalar(p, t.size), fl}
+			recv = Value{t, *(*unsafe.Pointer)(p), fl}
 		}
 	}
 	return chosen, recv, recvOK
@@ -2193,7 +2033,7 @@ func MakeSlice(typ Type, len, cap int) Value {
 	}
 
 	s := sliceHeader{unsafe_NewArray(typ.Elem().(*rtype), cap), len, cap}
-	return Value{typ.common(), unsafe.Pointer(&s), 0, flagIndir | flag(Slice)<<flagKindShift}
+	return Value{typ.common(), unsafe.Pointer(&s), flagIndir | flag(Slice)<<flagKindShift}
 }
 
 // MakeChan creates a new channel with the specified type and buffer size.
@@ -2208,7 +2048,7 @@ func MakeChan(typ Type, buffer int) Value {
 		panic("reflect.MakeChan: unidirectional channel type")
 	}
 	ch := makechan(typ.(*rtype), uint64(buffer))
-	return Value{typ.common(), ch, 0, flag(Chan) << flagKindShift}
+	return Value{typ.common(), ch, flag(Chan) << flagKindShift}
 }
 
 // MakeMap creates a new map of the specified type.
@@ -2217,7 +2057,7 @@ func MakeMap(typ Type) Value {
 		panic("reflect.MakeMap of non-map type")
 	}
 	m := makemap(typ.(*rtype))
-	return Value{typ.common(), m, 0, flag(Map) << flagKindShift}
+	return Value{typ.common(), m, flag(Map) << flagKindShift}
 }
 
 // Indirect returns the value that v points to.
@@ -2258,10 +2098,10 @@ func Zero(typ Type) Value {
 	}
 	t := typ.common()
 	fl := flag(t.Kind()) << flagKindShift
-	if isDirectIface(t) {
-		return Value{t, nil, 0, fl}
+	if ifaceIndir(t) {
+		return Value{t, unsafe_New(typ.(*rtype)), fl | flagIndir}
 	}
-	return Value{t, unsafe_New(typ.(*rtype)), 0, fl | flagIndir}
+	return Value{t, nil, fl}
 }
 
 // New returns a Value representing a pointer to a new zero value
@@ -2272,14 +2112,14 @@ func New(typ Type) Value {
 	}
 	ptr := unsafe_New(typ.(*rtype))
 	fl := flag(Ptr) << flagKindShift
-	return Value{typ.common().ptrTo(), ptr, 0, fl}
+	return Value{typ.common().ptrTo(), ptr, fl}
 }
 
 // NewAt returns a Value representing a pointer to a value of the
 // specified type, using p as that pointer.
 func NewAt(typ Type, p unsafe.Pointer) Value {
 	fl := flag(Ptr) << flagKindShift
-	return Value{typ.common().ptrTo(), p, 0, fl}
+	return Value{typ.common().ptrTo(), p, fl}
 }
 
 // assignTo returns a value v that can be assigned directly to typ.
@@ -2297,7 +2137,7 @@ func (v Value) assignTo(context string, dst *rtype, target *interface{}) Value {
 		v.typ = dst
 		fl := v.flag & (flagRO | flagAddr | flagIndir)
 		fl |= flag(dst.Kind()) << flagKindShift
-		return Value{dst, v.ptr, v.scalar, fl}
+		return Value{dst, v.ptr, fl}
 
 	case implements(dst, v.typ):
 		if target == nil {
@@ -2309,7 +2149,7 @@ func (v Value) assignTo(context string, dst *rtype, target *interface{}) Value {
 		} else {
 			ifaceE2I(dst, x, unsafe.Pointer(target))
 		}
-		return Value{dst, unsafe.Pointer(target), 0, flagIndir | flag(Interface)<<flagKindShift}
+		return Value{dst, unsafe.Pointer(target), flagIndir | flag(Interface)<<flagKindShift}
 	}
 
 	// Failed.
@@ -2417,82 +2257,46 @@ func convertOp(dst, src *rtype) func(Value, Type) Value {
 // where t is a signed or unsigned int type.
 func makeInt(f flag, bits uint64, t Type) Value {
 	typ := t.common()
-	if !isDirectIface(typ) {
-		ptr := unsafe_New(typ)
-		switch typ.size {
-		case 1:
-			*(*uint8)(unsafe.Pointer(ptr)) = uint8(bits)
-		case 2:
-			*(*uint16)(unsafe.Pointer(ptr)) = uint16(bits)
-		case 4:
-			*(*uint32)(unsafe.Pointer(ptr)) = uint32(bits)
-		case 8:
-			*(*uint64)(unsafe.Pointer(ptr)) = bits
-		}
-		return Value{typ, ptr, 0, f | flagIndir | flag(typ.Kind())<<flagKindShift}
-	}
-	var s uintptr
+	ptr := unsafe_New(typ)
 	switch typ.size {
 	case 1:
-		*(*uint8)(unsafe.Pointer(&s)) = uint8(bits)
+		*(*uint8)(unsafe.Pointer(ptr)) = uint8(bits)
 	case 2:
-		*(*uint16)(unsafe.Pointer(&s)) = uint16(bits)
+		*(*uint16)(unsafe.Pointer(ptr)) = uint16(bits)
 	case 4:
-		*(*uint32)(unsafe.Pointer(&s)) = uint32(bits)
+		*(*uint32)(unsafe.Pointer(ptr)) = uint32(bits)
 	case 8:
-		*(*uint64)(unsafe.Pointer(&s)) = uint64(bits)
+		*(*uint64)(unsafe.Pointer(ptr)) = bits
 	}
-	return Value{typ, nil, s, f | flag(typ.Kind())<<flagKindShift}
+	return Value{typ, ptr, f | flagIndir | flag(typ.Kind())<<flagKindShift}
 }
 
 // makeFloat returns a Value of type t equal to v (possibly truncated to float32),
 // where t is a float32 or float64 type.
 func makeFloat(f flag, v float64, t Type) Value {
 	typ := t.common()
-	if !isDirectIface(typ) {
-		ptr := unsafe_New(typ)
-		switch typ.size {
-		case 4:
-			*(*float32)(unsafe.Pointer(ptr)) = float32(v)
-		case 8:
-			*(*float64)(unsafe.Pointer(ptr)) = v
-		}
-		return Value{typ, ptr, 0, f | flagIndir | flag(typ.Kind())<<flagKindShift}
-	}
-
-	var s uintptr
+	ptr := unsafe_New(typ)
 	switch typ.size {
 	case 4:
-		*(*float32)(unsafe.Pointer(&s)) = float32(v)
+		*(*float32)(unsafe.Pointer(ptr)) = float32(v)
 	case 8:
-		*(*float64)(unsafe.Pointer(&s)) = v
+		*(*float64)(unsafe.Pointer(ptr)) = v
 	}
-	return Value{typ, nil, s, f | flag(typ.Kind())<<flagKindShift}
+	return Value{typ, ptr, f | flagIndir | flag(typ.Kind())<<flagKindShift}
 }
 
 // makeComplex returns a Value of type t equal to v (possibly truncated to complex64),
 // where t is a complex64 or complex128 type.
 func makeComplex(f flag, v complex128, t Type) Value {
 	typ := t.common()
-	if !isDirectIface(typ) {
-		ptr := unsafe_New(typ)
-		switch typ.size {
-		case 8:
-			*(*complex64)(unsafe.Pointer(ptr)) = complex64(v)
-		case 16:
-			*(*complex128)(unsafe.Pointer(ptr)) = v
-		}
-		return Value{typ, ptr, 0, f | flagIndir | flag(typ.Kind())<<flagKindShift}
-	}
-
-	var s uintptr
+	ptr := unsafe_New(typ)
 	switch typ.size {
 	case 8:
-		*(*complex64)(unsafe.Pointer(&s)) = complex64(v)
+		*(*complex64)(unsafe.Pointer(ptr)) = complex64(v)
 	case 16:
-		*(*complex128)(unsafe.Pointer(&s)) = v
+		*(*complex128)(unsafe.Pointer(ptr)) = v
 	}
-	return Value{typ, nil, s, f | flag(typ.Kind())<<flagKindShift}
+	return Value{typ, ptr, f | flagIndir | flag(typ.Kind())<<flagKindShift}
 }
 
 func makeString(f flag, v string, t Type) Value {
@@ -2603,7 +2407,7 @@ func cvtDirect(v Value, typ Type) Value {
 		ptr = c
 		f &^= flagAddr
 	}
-	return Value{t, ptr, v.scalar, v.flag&flagRO | f} // v.flag&flagRO|f == f?
+	return Value{t, ptr, v.flag&flagRO | f} // v.flag&flagRO|f == f?
 }
 
 // convertOp: concrete -> interface
@@ -2615,7 +2419,7 @@ func cvtT2I(v Value, typ Type) Value {
 	} else {
 		ifaceE2I(typ.(*rtype), x, unsafe.Pointer(target))
 	}
-	return Value{typ.common(), unsafe.Pointer(target), 0, v.flag&flagRO | flagIndir | flag(Interface)<<flagKindShift}
+	return Value{typ.common(), unsafe.Pointer(target), v.flag&flagRO | flagIndir | flag(Interface)<<flagKindShift}
 }
 
 // convertOp: interface -> interface
diff --git a/src/regexp/syntax/doc.go b/src/regexp/syntax/doc.go
index 8e72c90d3..e5e71f14f 100644
--- a/src/regexp/syntax/doc.go
+++ b/src/regexp/syntax/doc.go
@@ -21,8 +21,8 @@ Single characters:
   [^xyz]         negated character class
   \d             Perl character class
   \D             negated Perl character class
-  [:alpha:]      ASCII character class
-  [:^alpha:]     negated ASCII character class
+  [[:alpha:]]    ASCII character class
+  [[:^alpha:]]   negated ASCII character class
   \pN            Unicode character class (one-letter name)
   \p{Greek}      Unicode character class
   \PN            negated Unicode character class (one-letter name)
@@ -46,14 +46,14 @@ Repetitions:
   x{n,}?         n or more x, prefer fewer
   x{n}?          exactly n x
 
-Implementation restriction: The counting forms x{n} etc. (but not the other
-forms x* etc.) have an upper limit of n=1000. Negative or higher explicit
-counts yield the parse error ErrInvalidRepeatSize.
+Implementation restriction: The counting forms x{n,m}, x{n,}, and x{n}
+reject forms that create a minimum or maximum repetition count above 1000.
+Unlimited repetitions are not subject to this restriction.
 
 Grouping:
   (re)           numbered capturing group (submatch)
   (?P<name>re)   named & numbered capturing group (submatch)
-  (?:re)         non-capturing group (submatch)
+  (?:re)         non-capturing group
   (?flags)       set flags within current group; non-capturing
   (?flags:re)    set flags during re; non-capturing
 
@@ -69,7 +69,7 @@ Empty strings:
   $              at end of text (like \z not \Z) or line (flag m=true)
   \A             at beginning of text
   \b             at ASCII word boundary (\w on one side and \W, \A, or \z on the other)
-  \B             not an ASCII word boundary
+  \B             not at ASCII word boundary
   \z             at end of text
 
 Escape sequences:
@@ -103,29 +103,29 @@ Named character classes as character class elements:
   [\p{Name}]     named Unicode property inside character class (== \p{Name})
   [^\p{Name}]    named Unicode property inside negated character class (== \P{Name})
 
-Perl character classes:
+Perl character classes (all ASCII-only):
   \d             digits (== [0-9])
   \D             not digits (== [^0-9])
   \s             whitespace (== [\t\n\f\r ])
   \S             not whitespace (== [^\t\n\f\r ])
-  \w             ASCII word characters (== [0-9A-Za-z_])
-  \W             not ASCII word characters (== [^0-9A-Za-z_])
+  \w             word characters (== [0-9A-Za-z_])
+  \W             not word characters (== [^0-9A-Za-z_])
 
 ASCII character classes:
-  [:alnum:]      alphanumeric (== [0-9A-Za-z])
-  [:alpha:]      alphabetic (== [A-Za-z])
-  [:ascii:]      ASCII (== [\x00-\x7F])
-  [:blank:]      blank (== [\t ])
-  [:cntrl:]      control (== [\x00-\x1F\x7F])
-  [:digit:]      digits (== [0-9])
-  [:graph:]      graphical (== [!-~] == [A-Za-z0-9!"#$%&'()*+,\-./:;<=>?@[\\\]^_`{|}~])
-  [:lower:]      lower case (== [a-z])
-  [:print:]      printable (== [ -~] == [ [:graph:]])
-  [:punct:]      punctuation (== [!-/:-@[-`{-~])
-  [:space:]      whitespace (== [\t\n\v\f\r ])
-  [:upper:]      upper case (== [A-Z])
-  [:word:]       word characters (== [0-9A-Za-z_])
-  [:xdigit:]     hex digit (== [0-9A-Fa-f])
+  [[:alnum:]]    alphanumeric (== [0-9A-Za-z])
+  [[:alpha:]]    alphabetic (== [A-Za-z])
+  [[:ascii:]]    ASCII (== [\x00-\x7F])
+  [[:blank:]]    blank (== [\t ])
+  [[:cntrl:]]    control (== [\x00-\x1F\x7F])
+  [[:digit:]]    digits (== [0-9])
+  [[:graph:]]    graphical (== [!-~] == [A-Za-z0-9!"#$%&'()*+,\-./:;<=>?@[\\\]^_`{|}~])
+  [[:lower:]]    lower case (== [a-z])
+  [[:print:]]    printable (== [ -~] == [ [:graph:]])
+  [[:punct:]]    punctuation (== [!-/:-@[-`{-~])
+  [[:space:]]    whitespace (== [\t\n\v\f\r ])
+  [[:upper:]]    upper case (== [A-Z])
+  [[:word:]]     word characters (== [0-9A-Za-z_])
+  [[:xdigit:]]   hex digit (== [0-9A-Fa-f])
 
 */
 package syntax
diff --git a/src/runtime/asm_386.s b/src/runtime/asm_386.s
index 1495246a2..b0ed2d8ce 100644
--- a/src/runtime/asm_386.s
+++ b/src/runtime/asm_386.s
@@ -353,7 +353,7 @@ TEXT runtime·morestack_noctxt(SB),NOSPLIT,$0-0
 	JMP	AX
 // Note: can't just "JMP NAME(SB)" - bad inlining results.
 
-TEXT runtime·reflectcall(SB), NOSPLIT, $0-16
+TEXT ·reflectcall(SB), NOSPLIT, $0-16
 	MOVL	argsize+8(FP), CX
 	DISPATCH(runtime·call16, 16)
 	DISPATCH(runtime·call32, 32)
@@ -385,21 +385,9 @@ TEXT runtime·reflectcall(SB), NOSPLIT, $0-16
 	MOVL	$runtime·badreflectcall(SB), AX
 	JMP	AX
 
-// Argument map for the callXX frames.  Each has one stack map.
-DATA gcargs_reflectcall<>+0x00(SB)/4, $1  // 1 stackmap
-DATA gcargs_reflectcall<>+0x04(SB)/4, $8  // 4 words
-DATA gcargs_reflectcall<>+0x08(SB)/1, $(const_BitsPointer+(const_BitsPointer<<2)+(const_BitsScalar<<4)+(const_BitsScalar<<6))
-GLOBL gcargs_reflectcall<>(SB),RODATA,$12
-
-// callXX frames have no locals
-DATA gclocals_reflectcall<>+0x00(SB)/4, $1  // 1 stackmap
-DATA gclocals_reflectcall<>+0x04(SB)/4, $0  // 0 locals
-GLOBL gclocals_reflectcall<>(SB),RODATA,$8
-
 #define CALLFN(NAME,MAXSIZE)			\
-TEXT NAME(SB), WRAPPER, $MAXSIZE-16;	\
-	FUNCDATA $FUNCDATA_ArgsPointerMaps,gcargs_reflectcall<>(SB);	\
-	FUNCDATA $FUNCDATA_LocalsPointerMaps,gclocals_reflectcall<>(SB);\
+TEXT NAME(SB), WRAPPER, $MAXSIZE-16;		\
+	NO_LOCAL_POINTERS;			\
 	/* copy arguments to stack */		\
 	MOVL	argptr+4(FP), SI;		\
 	MOVL	argsize+8(FP), CX;		\
@@ -421,33 +409,33 @@ TEXT NAME(SB), WRAPPER, $MAXSIZE-16;	\
 	REP;MOVSB;				\
 	RET
 
-CALLFN(runtime·call16, 16)
-CALLFN(runtime·call32, 32)
-CALLFN(runtime·call64, 64)
-CALLFN(runtime·call128, 128)
-CALLFN(runtime·call256, 256)
-CALLFN(runtime·call512, 512)
-CALLFN(runtime·call1024, 1024)
-CALLFN(runtime·call2048, 2048)
-CALLFN(runtime·call4096, 4096)
-CALLFN(runtime·call8192, 8192)
-CALLFN(runtime·call16384, 16384)
-CALLFN(runtime·call32768, 32768)
-CALLFN(runtime·call65536, 65536)
-CALLFN(runtime·call131072, 131072)
-CALLFN(runtime·call262144, 262144)
-CALLFN(runtime·call524288, 524288)
-CALLFN(runtime·call1048576, 1048576)
-CALLFN(runtime·call2097152, 2097152)
-CALLFN(runtime·call4194304, 4194304)
-CALLFN(runtime·call8388608, 8388608)
-CALLFN(runtime·call16777216, 16777216)
-CALLFN(runtime·call33554432, 33554432)
-CALLFN(runtime·call67108864, 67108864)
-CALLFN(runtime·call134217728, 134217728)
-CALLFN(runtime·call268435456, 268435456)
-CALLFN(runtime·call536870912, 536870912)
-CALLFN(runtime·call1073741824, 1073741824)
+CALLFN(·call16, 16)
+CALLFN(·call32, 32)
+CALLFN(·call64, 64)
+CALLFN(·call128, 128)
+CALLFN(·call256, 256)
+CALLFN(·call512, 512)
+CALLFN(·call1024, 1024)
+CALLFN(·call2048, 2048)
+CALLFN(·call4096, 4096)
+CALLFN(·call8192, 8192)
+CALLFN(·call16384, 16384)
+CALLFN(·call32768, 32768)
+CALLFN(·call65536, 65536)
+CALLFN(·call131072, 131072)
+CALLFN(·call262144, 262144)
+CALLFN(·call524288, 524288)
+CALLFN(·call1048576, 1048576)
+CALLFN(·call2097152, 2097152)
+CALLFN(·call4194304, 4194304)
+CALLFN(·call8388608, 8388608)
+CALLFN(·call16777216, 16777216)
+CALLFN(·call33554432, 33554432)
+CALLFN(·call67108864, 67108864)
+CALLFN(·call134217728, 134217728)
+CALLFN(·call268435456, 268435456)
+CALLFN(·call536870912, 536870912)
+CALLFN(·call1073741824, 1073741824)
 
 // bool cas(int32 *val, int32 old, int32 new)
 // Atomically:
@@ -479,6 +467,9 @@ TEXT runtime·atomicloaduintptr(SB), NOSPLIT, $0-8
 TEXT runtime·atomicloaduint(SB), NOSPLIT, $0-8
 	JMP	runtime·atomicload(SB)
 
+TEXT runtime·atomicstoreuintptr(SB), NOSPLIT, $0-8
+	JMP	runtime·atomicstore(SB)
+
 // bool runtime·cas64(uint64 *val, uint64 old, uint64 new)
 // Atomically:
 //	if(*val == *old){
diff --git a/src/runtime/asm_amd64.s b/src/runtime/asm_amd64.s
index 3f7f60841..2ee331208 100644
--- a/src/runtime/asm_amd64.s
+++ b/src/runtime/asm_amd64.s
@@ -339,11 +339,11 @@ TEXT runtime·morestack_noctxt(SB),NOSPLIT,$0
 #define DISPATCH(NAME,MAXSIZE)		\
 	CMPQ	CX, $MAXSIZE;		\
 	JA	3(PC);			\
-	MOVQ	$NAME(SB), AX;	\
+	MOVQ	$NAME(SB), AX;		\
 	JMP	AX
 // Note: can't just "JMP NAME(SB)" - bad inlining results.
 
-TEXT runtime·reflectcall(SB), NOSPLIT, $0-24
+TEXT ·reflectcall(SB), NOSPLIT, $0-24
 	MOVLQZX argsize+16(FP), CX
 	DISPATCH(runtime·call16, 16)
 	DISPATCH(runtime·call32, 32)
@@ -375,21 +375,9 @@ TEXT runtime·reflectcall(SB), NOSPLIT, $0-24
 	MOVQ	$runtime·badreflectcall(SB), AX
 	JMP	AX
 
-// Argument map for the callXX frames.  Each has one stack map.
-DATA gcargs_reflectcall<>+0x00(SB)/4, $1  // 1 stackmap
-DATA gcargs_reflectcall<>+0x04(SB)/4, $6  // 3 words
-DATA gcargs_reflectcall<>+0x08(SB)/1, $(const_BitsPointer+(const_BitsPointer<<2)+(const_BitsScalar<<4))
-GLOBL gcargs_reflectcall<>(SB),RODATA,$12
-
-// callXX frames have no locals
-DATA gclocals_reflectcall<>+0x00(SB)/4, $1  // 1 stackmap
-DATA gclocals_reflectcall<>+0x04(SB)/4, $0  // 0 locals
-GLOBL gclocals_reflectcall<>(SB),RODATA,$8
-
 #define CALLFN(NAME,MAXSIZE)			\
 TEXT NAME(SB), WRAPPER, $MAXSIZE-24;		\
-	FUNCDATA $FUNCDATA_ArgsPointerMaps,gcargs_reflectcall<>(SB);	\
-	FUNCDATA $FUNCDATA_LocalsPointerMaps,gclocals_reflectcall<>(SB);\
+	NO_LOCAL_POINTERS;			\
 	/* copy arguments to stack */		\
 	MOVQ	argptr+8(FP), SI;		\
 	MOVLQZX argsize+16(FP), CX;		\
@@ -410,33 +398,33 @@ TEXT NAME(SB), WRAPPER, $MAXSIZE-24;		\
 	REP;MOVSB;				\
 	RET
 
-CALLFN(runtime·call16, 16)
-CALLFN(runtime·call32, 32)
-CALLFN(runtime·call64, 64)
-CALLFN(runtime·call128, 128)
-CALLFN(runtime·call256, 256)
-CALLFN(runtime·call512, 512)
-CALLFN(runtime·call1024, 1024)
-CALLFN(runtime·call2048, 2048)
-CALLFN(runtime·call4096, 4096)
-CALLFN(runtime·call8192, 8192)
-CALLFN(runtime·call16384, 16384)
-CALLFN(runtime·call32768, 32768)
-CALLFN(runtime·call65536, 65536)
-CALLFN(runtime·call131072, 131072)
-CALLFN(runtime·call262144, 262144)
-CALLFN(runtime·call524288, 524288)
-CALLFN(runtime·call1048576, 1048576)
-CALLFN(runtime·call2097152, 2097152)
-CALLFN(runtime·call4194304, 4194304)
-CALLFN(runtime·call8388608, 8388608)
-CALLFN(runtime·call16777216, 16777216)
-CALLFN(runtime·call33554432, 33554432)
-CALLFN(runtime·call67108864, 67108864)
-CALLFN(runtime·call134217728, 134217728)
-CALLFN(runtime·call268435456, 268435456)
-CALLFN(runtime·call536870912, 536870912)
-CALLFN(runtime·call1073741824, 1073741824)
+CALLFN(·call16, 16)
+CALLFN(·call32, 32)
+CALLFN(·call64, 64)
+CALLFN(·call128, 128)
+CALLFN(·call256, 256)
+CALLFN(·call512, 512)
+CALLFN(·call1024, 1024)
+CALLFN(·call2048, 2048)
+CALLFN(·call4096, 4096)
+CALLFN(·call8192, 8192)
+CALLFN(·call16384, 16384)
+CALLFN(·call32768, 32768)
+CALLFN(·call65536, 65536)
+CALLFN(·call131072, 131072)
+CALLFN(·call262144, 262144)
+CALLFN(·call524288, 524288)
+CALLFN(·call1048576, 1048576)
+CALLFN(·call2097152, 2097152)
+CALLFN(·call4194304, 4194304)
+CALLFN(·call8388608, 8388608)
+CALLFN(·call16777216, 16777216)
+CALLFN(·call33554432, 33554432)
+CALLFN(·call67108864, 67108864)
+CALLFN(·call134217728, 134217728)
+CALLFN(·call268435456, 268435456)
+CALLFN(·call536870912, 536870912)
+CALLFN(·call1073741824, 1073741824)
 
 // bool cas(int32 *val, int32 old, int32 new)
 // Atomically:
@@ -491,6 +479,9 @@ TEXT runtime·atomicloaduintptr(SB), NOSPLIT, $0-16
 TEXT runtime·atomicloaduint(SB), NOSPLIT, $0-16
 	JMP	runtime·atomicload64(SB)
 
+TEXT runtime·atomicstoreuintptr(SB), NOSPLIT, $0-16
+	JMP	runtime·atomicstore64(SB)
+
 // bool casp(void **val, void *old, void *new)
 // Atomically:
 //	if(*val == old){
diff --git a/src/runtime/asm_amd64p32.s b/src/runtime/asm_amd64p32.s
index 13a164256..e27f67e1e 100644
--- a/src/runtime/asm_amd64p32.s
+++ b/src/runtime/asm_amd64p32.s
@@ -310,11 +310,11 @@ TEXT runtime·morestack_noctxt(SB),NOSPLIT,$0
 #define DISPATCH(NAME,MAXSIZE)		\
 	CMPL	CX, $MAXSIZE;		\
 	JA	3(PC);			\
-	MOVL	$NAME(SB), AX;	\
+	MOVL	$NAME(SB), AX;		\
 	JMP	AX
 // Note: can't just "JMP NAME(SB)" - bad inlining results.
 
-TEXT runtime·reflectcall(SB), NOSPLIT, $0-16
+TEXT ·reflectcall(SB), NOSPLIT, $0-16
 	MOVLQZX argsize+8(FP), CX
 	DISPATCH(runtime·call16, 16)
 	DISPATCH(runtime·call32, 32)
@@ -346,22 +346,9 @@ TEXT runtime·reflectcall(SB), NOSPLIT, $0-16
 	MOVL	$runtime·badreflectcall(SB), AX
 	JMP	AX
 
-// Argument map for the callXX frames.  Each has one stack map.
-DATA gcargs_reflectcall<>+0x00(SB)/4, $1  // 1 stackmap
-DATA gcargs_reflectcall<>+0x04(SB)/4, $10  // 5 words
-DATA gcargs_reflectcall<>+0x08(SB)/1, $(const_BitsPointer+(const_BitsPointer<<2)+(const_BitsScalar<<4)+(const_BitsScalar<<6))
-DATA gcargs_reflectcall<>+0x09(SB)/1, $(const_BitsPointer)
-GLOBL gcargs_reflectcall<>(SB),RODATA,$12
-
-// callXX frames have no locals
-DATA gclocals_reflectcall<>+0x00(SB)/4, $1  // 1 stackmap
-DATA gclocals_reflectcall<>+0x04(SB)/4, $0  // 0 locals
-GLOBL gclocals_reflectcall<>(SB),RODATA,$8
-
 #define CALLFN(NAME,MAXSIZE)			\
 TEXT NAME(SB), WRAPPER, $MAXSIZE-16;		\
-	FUNCDATA $FUNCDATA_ArgsPointerMaps,gcargs_reflectcall<>(SB);	\
-	FUNCDATA $FUNCDATA_LocalsPointerMaps,gclocals_reflectcall<>(SB);\
+	NO_LOCAL_POINTERS;			\
 	/* copy arguments to stack */		\
 	MOVL	argptr+4(FP), SI;		\
 	MOVL	argsize+8(FP), CX;		\
@@ -369,8 +356,8 @@ TEXT NAME(SB), WRAPPER, $MAXSIZE-16;		\
 	REP;MOVSB;				\
 	/* call function */			\
 	MOVL	f+0(FP), DX;			\
-	MOVL	(DX), AX;				\
-	CALL	AX; \
+	MOVL	(DX), AX;			\
+	CALL	AX;				\
 	/* copy return values back */		\
 	MOVL	argptr+4(FP), DI;		\
 	MOVL	argsize+8(FP), CX;		\
@@ -382,33 +369,33 @@ TEXT NAME(SB), WRAPPER, $MAXSIZE-16;		\
 	REP;MOVSB;				\
 	RET
 
-CALLFN(runtime·call16, 16)
-CALLFN(runtime·call32, 32)
-CALLFN(runtime·call64, 64)
-CALLFN(runtime·call128, 128)
-CALLFN(runtime·call256, 256)
-CALLFN(runtime·call512, 512)
-CALLFN(runtime·call1024, 1024)
-CALLFN(runtime·call2048, 2048)
-CALLFN(runtime·call4096, 4096)
-CALLFN(runtime·call8192, 8192)
-CALLFN(runtime·call16384, 16384)
-CALLFN(runtime·call32768, 32768)
-CALLFN(runtime·call65536, 65536)
-CALLFN(runtime·call131072, 131072)
-CALLFN(runtime·call262144, 262144)
-CALLFN(runtime·call524288, 524288)
-CALLFN(runtime·call1048576, 1048576)
-CALLFN(runtime·call2097152, 2097152)
-CALLFN(runtime·call4194304, 4194304)
-CALLFN(runtime·call8388608, 8388608)
-CALLFN(runtime·call16777216, 16777216)
-CALLFN(runtime·call33554432, 33554432)
-CALLFN(runtime·call67108864, 67108864)
-CALLFN(runtime·call134217728, 134217728)
-CALLFN(runtime·call268435456, 268435456)
-CALLFN(runtime·call536870912, 536870912)
-CALLFN(runtime·call1073741824, 1073741824)
+CALLFN(·call16, 16)
+CALLFN(·call32, 32)
+CALLFN(·call64, 64)
+CALLFN(·call128, 128)
+CALLFN(·call256, 256)
+CALLFN(·call512, 512)
+CALLFN(·call1024, 1024)
+CALLFN(·call2048, 2048)
+CALLFN(·call4096, 4096)
+CALLFN(·call8192, 8192)
+CALLFN(·call16384, 16384)
+CALLFN(·call32768, 32768)
+CALLFN(·call65536, 65536)
+CALLFN(·call131072, 131072)
+CALLFN(·call262144, 262144)
+CALLFN(·call524288, 524288)
+CALLFN(·call1048576, 1048576)
+CALLFN(·call2097152, 2097152)
+CALLFN(·call4194304, 4194304)
+CALLFN(·call8388608, 8388608)
+CALLFN(·call16777216, 16777216)
+CALLFN(·call33554432, 33554432)
+CALLFN(·call67108864, 67108864)
+CALLFN(·call134217728, 134217728)
+CALLFN(·call268435456, 268435456)
+CALLFN(·call536870912, 536870912)
+CALLFN(·call1073741824, 1073741824)
 
 // bool cas(int32 *val, int32 old, int32 new)
 // Atomically:
@@ -440,6 +427,9 @@ TEXT runtime·atomicloaduintptr(SB), NOSPLIT, $0-12
 TEXT runtime·atomicloaduint(SB), NOSPLIT, $0-12
 	JMP	runtime·atomicload(SB)
 
+TEXT runtime·atomicstoreuintptr(SB), NOSPLIT, $0-12
+	JMP	runtime·atomicstore(SB)
+
 // bool	runtime·cas64(uint64 *val, uint64 old, uint64 new)
 // Atomically:
 //	if(*val == *old){
diff --git a/src/runtime/asm_arm.s b/src/runtime/asm_arm.s
index 36fb022f9..b21441488 100644
--- a/src/runtime/asm_arm.s
+++ b/src/runtime/asm_arm.s
@@ -343,7 +343,7 @@ TEXT runtime·morestack_noctxt(SB),NOSPLIT,$-4-0
 	MOVW	$NAME(SB), R1;		\
 	B	(R1)
 
-TEXT runtime·reflectcall(SB),NOSPLIT,$-4-16
+TEXT ·reflectcall(SB),NOSPLIT,$-4-16
 	MOVW	argsize+8(FP), R0
 	DISPATCH(runtime·call16, 16)
 	DISPATCH(runtime·call32, 32)
@@ -375,21 +375,9 @@ TEXT runtime·reflectcall(SB),NOSPLIT,$-4-16
 	MOVW	$runtime·badreflectcall(SB), R1
 	B	(R1)
 
-// Argument map for the callXX frames.  Each has one stack map.
-DATA gcargs_reflectcall<>+0x00(SB)/4, $1  // 1 stackmap
-DATA gcargs_reflectcall<>+0x04(SB)/4, $8  // 4 words
-DATA gcargs_reflectcall<>+0x08(SB)/1, $(const_BitsPointer+(const_BitsPointer<<2)+(const_BitsScalar<<4)+(const_BitsScalar<<6))
-GLOBL gcargs_reflectcall<>(SB),RODATA,$12
-
-// callXX frames have no locals
-DATA gclocals_reflectcall<>+0x00(SB)/4, $1  // 1 stackmap
-DATA gclocals_reflectcall<>+0x04(SB)/4, $0  // 0 locals
-GLOBL gclocals_reflectcall<>(SB),RODATA,$8
-
 #define CALLFN(NAME,MAXSIZE)			\
 TEXT NAME(SB), WRAPPER, $MAXSIZE-16;		\
-	FUNCDATA $FUNCDATA_ArgsPointerMaps,gcargs_reflectcall<>(SB);	\
-	FUNCDATA $FUNCDATA_LocalsPointerMaps,gclocals_reflectcall<>(SB);\
+	NO_LOCAL_POINTERS;			\
 	/* copy arguments to stack */		\
 	MOVW	argptr+4(FP), R0;		\
 	MOVW	argsize+8(FP), R2;		\
@@ -420,33 +408,33 @@ TEXT NAME(SB), WRAPPER, $MAXSIZE-16;		\
 	SUB	$1, R2, R2;			\
 	B	-5(PC)				\
 
-CALLFN(runtime·call16, 16)
-CALLFN(runtime·call32, 32)
-CALLFN(runtime·call64, 64)
-CALLFN(runtime·call128, 128)
-CALLFN(runtime·call256, 256)
-CALLFN(runtime·call512, 512)
-CALLFN(runtime·call1024, 1024)
-CALLFN(runtime·call2048, 2048)
-CALLFN(runtime·call4096, 4096)
-CALLFN(runtime·call8192, 8192)
-CALLFN(runtime·call16384, 16384)
-CALLFN(runtime·call32768, 32768)
-CALLFN(runtime·call65536, 65536)
-CALLFN(runtime·call131072, 131072)
-CALLFN(runtime·call262144, 262144)
-CALLFN(runtime·call524288, 524288)
-CALLFN(runtime·call1048576, 1048576)
-CALLFN(runtime·call2097152, 2097152)
-CALLFN(runtime·call4194304, 4194304)
-CALLFN(runtime·call8388608, 8388608)
-CALLFN(runtime·call16777216, 16777216)
-CALLFN(runtime·call33554432, 33554432)
-CALLFN(runtime·call67108864, 67108864)
-CALLFN(runtime·call134217728, 134217728)
-CALLFN(runtime·call268435456, 268435456)
-CALLFN(runtime·call536870912, 536870912)
-CALLFN(runtime·call1073741824, 1073741824)
+CALLFN(·call16, 16)
+CALLFN(·call32, 32)
+CALLFN(·call64, 64)
+CALLFN(·call128, 128)
+CALLFN(·call256, 256)
+CALLFN(·call512, 512)
+CALLFN(·call1024, 1024)
+CALLFN(·call2048, 2048)
+CALLFN(·call4096, 4096)
+CALLFN(·call8192, 8192)
+CALLFN(·call16384, 16384)
+CALLFN(·call32768, 32768)
+CALLFN(·call65536, 65536)
+CALLFN(·call131072, 131072)
+CALLFN(·call262144, 262144)
+CALLFN(·call524288, 524288)
+CALLFN(·call1048576, 1048576)
+CALLFN(·call2097152, 2097152)
+CALLFN(·call4194304, 4194304)
+CALLFN(·call8388608, 8388608)
+CALLFN(·call16777216, 16777216)
+CALLFN(·call33554432, 33554432)
+CALLFN(·call67108864, 67108864)
+CALLFN(·call134217728, 134217728)
+CALLFN(·call268435456, 268435456)
+CALLFN(·call536870912, 536870912)
+CALLFN(·call1073741824, 1073741824)
 
 // void jmpdefer(fn, sp);
 // called from deferreturn.
@@ -724,6 +712,9 @@ TEXT runtime·atomicloaduintptr(SB),NOSPLIT,$0-8
 TEXT runtime·atomicloaduint(SB),NOSPLIT,$0-8
 	B	runtime·atomicload(SB)
 
+TEXT runtime·atomicstoreuintptr(SB),NOSPLIT,$0-8
+	B	runtime·atomicstore(SB)
+
 // AES hashing not implemented for ARM
 TEXT runtime·aeshash(SB),NOSPLIT,$-4-0
 	MOVW	$0, R0
diff --git a/src/runtime/cgocallback.go b/src/runtime/cgocallback.go
index 1e1b57607..2c8914320 100644
--- a/src/runtime/cgocallback.go
+++ b/src/runtime/cgocallback.go
@@ -21,6 +21,9 @@ import "unsafe"
 // Either we need to add types or we need to stop using it.
 
 func _cgo_allocate_internal(len uintptr) unsafe.Pointer {
+	if len == 0 {
+		len = 1
+	}
 	ret := unsafe.Pointer(&make([]unsafe.Pointer, (len+ptrSize-1)/ptrSize)[0])
 	c := new(cgomal)
 	c.alloc = ret
diff --git a/src/runtime/chan.go b/src/runtime/chan.go
index 10503f4e1..004970182 100644
--- a/src/runtime/chan.go
+++ b/src/runtime/chan.go
@@ -174,6 +174,10 @@ func chansend(t *chantype, c *hchan, ep unsafe.Pointer, block bool, callerpc uin
 		goparkunlock(&c.lock, "chan send")
 
 		// someone woke us up.
+		if mysg != gp.waiting {
+			gothrow("G waiting list is corrupted!")
+		}
+		gp.waiting = nil
 		if gp.param == nil {
 			if c.closed == 0 {
 				gothrow("chansend: spurious wakeup")
@@ -184,10 +188,6 @@ func chansend(t *chantype, c *hchan, ep unsafe.Pointer, block bool, callerpc uin
 		if mysg.releasetime > 0 {
 			blockevent(int64(mysg.releasetime)-t0, 2)
 		}
-		if mysg != gp.waiting {
-			gothrow("G waiting list is corrupted!")
-		}
-		gp.waiting = nil
 		releaseSudog(mysg)
 		return true
 	}
@@ -410,6 +410,9 @@ func chanrecv(t *chantype, c *hchan, ep unsafe.Pointer, block bool) (selected, r
 		goparkunlock(&c.lock, "chan receive")
 
 		// someone woke us up
+		if mysg != gp.waiting {
+			gothrow("G waiting list is corrupted!")
+		}
 		gp.waiting = nil
 		if mysg.releasetime > 0 {
 			blockevent(mysg.releasetime-t0, 2)
diff --git a/src/runtime/defs_windows.go b/src/runtime/defs_windows.go
index cb0f54d8a..7ce679741 100644
--- a/src/runtime/defs_windows.go
+++ b/src/runtime/defs_windows.go
@@ -49,6 +49,7 @@ const (
 	CONTEXT_FULL    = C.CONTEXT_FULL
 
 	EXCEPTION_ACCESS_VIOLATION     = C.STATUS_ACCESS_VIOLATION
+	EXCEPTION_BREAKPOINT           = C.STATUS_BREAKPOINT
 	EXCEPTION_FLT_DENORMAL_OPERAND = C.STATUS_FLOAT_DENORMAL_OPERAND
 	EXCEPTION_FLT_DIVIDE_BY_ZERO   = C.STATUS_FLOAT_DIVIDE_BY_ZERO
 	EXCEPTION_FLT_INEXACT_RESULT   = C.STATUS_FLOAT_INEXACT_RESULT
@@ -59,6 +60,9 @@ const (
 
 	INFINITE     = C.INFINITE
 	WAIT_TIMEOUT = C.WAIT_TIMEOUT
+
+	EXCEPTION_CONTINUE_EXECUTION = C.EXCEPTION_CONTINUE_EXECUTION
+	EXCEPTION_CONTINUE_SEARCH    = C.EXCEPTION_CONTINUE_SEARCH
 )
 
 type SystemInfo C.SYSTEM_INFO
diff --git a/src/runtime/defs_windows_386.h b/src/runtime/defs_windows_386.h
index 295e422c6..2317c04f6 100644
--- a/src/runtime/defs_windows_386.h
+++ b/src/runtime/defs_windows_386.h
@@ -22,6 +22,7 @@ enum {
 	CONTEXT_FULL	= 0x10007,
 
 	EXCEPTION_ACCESS_VIOLATION	= 0xc0000005,
+	EXCEPTION_BREAKPOINT		= 0x80000003,
 	EXCEPTION_FLT_DENORMAL_OPERAND	= 0xc000008d,
 	EXCEPTION_FLT_DIVIDE_BY_ZERO	= 0xc000008e,
 	EXCEPTION_FLT_INEXACT_RESULT	= 0xc000008f,
@@ -32,6 +33,9 @@ enum {
 
 	INFINITE	= 0xffffffff,
 	WAIT_TIMEOUT	= 0x102,
+
+	EXCEPTION_CONTINUE_EXECUTION	= -0x1,
+	EXCEPTION_CONTINUE_SEARCH	= 0x0,
 };
 
 typedef struct SystemInfo SystemInfo;
diff --git a/src/runtime/defs_windows_amd64.h b/src/runtime/defs_windows_amd64.h
index 2516c8412..7f37a7a8c 100644
--- a/src/runtime/defs_windows_amd64.h
+++ b/src/runtime/defs_windows_amd64.h
@@ -22,6 +22,7 @@ enum {
 	CONTEXT_FULL	= 0x10000b,
 
 	EXCEPTION_ACCESS_VIOLATION	= 0xc0000005,
+	EXCEPTION_BREAKPOINT		= 0x80000003,
 	EXCEPTION_FLT_DENORMAL_OPERAND	= 0xc000008d,
 	EXCEPTION_FLT_DIVIDE_BY_ZERO	= 0xc000008e,
 	EXCEPTION_FLT_INEXACT_RESULT	= 0xc000008f,
@@ -32,6 +33,9 @@ enum {
 
 	INFINITE	= 0xffffffff,
 	WAIT_TIMEOUT	= 0x102,
+
+	EXCEPTION_CONTINUE_EXECUTION	= -0x1,
+	EXCEPTION_CONTINUE_SEARCH	= 0x0,
 };
 
 typedef struct SystemInfo SystemInfo;
diff --git a/src/runtime/heapdump.c b/src/runtime/heapdump.c
index 54b9666b5..71da419f1 100644
--- a/src/runtime/heapdump.c
+++ b/src/runtime/heapdump.c
@@ -7,7 +7,7 @@
 // finalizers, etc.) to a file.
 
 // The format of the dumped file is described at
-// http://code.google.com/p/go-wiki/wiki/heapdump13
+// http://code.google.com/p/go-wiki/wiki/heapdump14
 
 #include "runtime.h"
 #include "arch_GOARCH.h"
@@ -27,10 +27,8 @@ extern byte runtime·ebss[];
 enum {
 	FieldKindEol = 0,
 	FieldKindPtr = 1,
-	FieldKindString = 2,
-	FieldKindSlice = 3,
-	FieldKindIface = 4,
-	FieldKindEface = 5,
+	FieldKindIface = 2,
+	FieldKindEface = 3,
 
 	TagEOF = 0,
 	TagObject = 1,
@@ -200,7 +198,6 @@ dumptype(Type *t)
 		write(t->x->name->str, t->x->name->len);
 	}
 	dumpbool((t->kind & KindDirectIface) == 0 || (t->kind & KindNoPointers) == 0);
-	dumpfields((BitVector){0, nil});
 }
 
 // dump an object
@@ -210,9 +207,8 @@ dumpobj(byte *obj, uintptr size, BitVector bv)
 	dumpbvtypes(&bv, obj);
 	dumpint(TagObject);
 	dumpint((uintptr)obj);
-	dumpint(0); // Type*
-	dumpint(0); // kind
 	dumpmemrange(obj, size);
+	dumpfields(bv);
 }
 
 static void
@@ -255,6 +251,7 @@ dumpbv(BitVector *bv, uintptr offset)
 	for(i = 0; i < bv->n; i += BitsPerPointer) {
 		switch(bv->bytedata[i/8] >> i%8 & 3) {
 		case BitsDead:
+			return;
 		case BitsScalar:
 			break;
 		case BitsPointer:
@@ -489,16 +486,18 @@ dumproots(void)
 	byte *p;
 
 	// data segment
+	dumpbvtypes(&runtime·gcdatamask, runtime·data);
 	dumpint(TagData);
 	dumpint((uintptr)runtime·data);
 	dumpmemrange(runtime·data, runtime·edata - runtime·data);
 	dumpfields(runtime·gcdatamask);
 
 	// bss segment
+	dumpbvtypes(&runtime·gcbssmask, runtime·bss);
 	dumpint(TagBss);
 	dumpint((uintptr)runtime·bss);
 	dumpmemrange(runtime·bss, runtime·ebss - runtime·bss);
-	dumpfields(runtime·gcdatamask);
+	dumpfields(runtime·gcbssmask);
 
 	// MSpan.types
 	allspans = runtime·mheap.allspans;
@@ -578,10 +577,29 @@ itab_callback(Itab *tab)
 {
 	Type *t;
 
-	dumpint(TagItab);
-	dumpint((uintptr)tab);
 	t = tab->type;
-	dumpbool((t->kind & KindDirectIface) == 0 || (t->kind & KindNoPointers) == 0);
+	// Dump a map from itab* to the type of its data field.
+	// We want this map so we can deduce types of interface referents.
+	if((t->kind & KindDirectIface) == 0) {
+		// indirect - data slot is a pointer to t.
+		dumptype(t->ptrto);
+		dumpint(TagItab);
+		dumpint((uintptr)tab);
+		dumpint((uintptr)t->ptrto);
+	} else if((t->kind & KindNoPointers) == 0) {
+		// t is pointer-like - data slot is a t.
+		dumptype(t);
+		dumpint(TagItab);
+		dumpint((uintptr)tab);
+		dumpint((uintptr)t);
+	} else {
+		// Data slot is a scalar.  Dump type just for fun.
+		// With pointer-only interfaces, this shouldn't happen.
+		dumptype(t);
+		dumpint(TagItab);
+		dumpint((uintptr)tab);
+		dumpint((uintptr)t);
+	}
 }
 
 static void
@@ -726,7 +744,7 @@ mdump(void)
 	}
 
 	runtime·memclr((byte*)&typecache[0], sizeof(typecache));
-	hdr = (byte*)"go1.3 heap dump\n";
+	hdr = (byte*)"go1.4 heap dump\n";
 	write(hdr, runtime·findnull(hdr));
 	dumpparams();
 	dumpitabs();
diff --git a/src/runtime/malloc.go b/src/runtime/malloc.go
index 99d14e314..9b4264f2b 100644
--- a/src/runtime/malloc.go
+++ b/src/runtime/malloc.go
@@ -270,7 +270,7 @@ func mallocgc(size uintptr, typ *_type, flags int) unsafe.Pointer {
 			}
 			ptrmask = (*uint8)(add(unsafe.Pointer(ptrmask), 1)) // skip the unroll flag byte
 		} else {
-			ptrmask = (*uint8)(unsafe.Pointer(&typ.gc[0])) // embed mask
+			ptrmask = (*uint8)(unsafe.Pointer(typ.gc[0])) // pointer to unrolled mask
 		}
 		if size == 2*ptrSize {
 			*xbits = *ptrmask | bitBoundary
diff --git a/src/runtime/mgc0.c b/src/runtime/mgc0.c
index dabd38a60..8620f47af 100644
--- a/src/runtime/mgc0.c
+++ b/src/runtime/mgc0.c
@@ -383,25 +383,19 @@ greyobject(byte *obj, Markbits *mbits, Workbuf *wbuf)
 static Workbuf*
 scanobject(byte *b, uintptr n, byte *ptrmask, Workbuf *wbuf)
 {
-	byte *obj, *arena_start, *arena_used, *ptrbitp, bits, cshift, cached;
-	uintptr i;
-	intptr ncached;
+	byte *obj, *arena_start, *arena_used, *ptrbitp;
+	uintptr i, j;
+	int32 bits;
 	Markbits mbits;
 
 	arena_start = (byte*)runtime·mheap.arena_start;
 	arena_used = runtime·mheap.arena_used;
 	ptrbitp = nil;
-	cached = 0;
-	ncached = 0;
 
 	// Find bits of the beginning of the object.
 	if(ptrmask == nil) {
 		b = objectstart(b, &mbits);
 		ptrbitp = mbits.bitp; //arena_start - off/wordsPerBitmapByte - 1;
-		cshift = mbits.shift; //(off % wordsPerBitmapByte) * gcBits;
-		cached = *ptrbitp >> cshift;
-		cached &= ~bitBoundary;
-		ncached = (8 - cshift)/gcBits;
 	}
 	for(i = 0; i < n; i += PtrSize) {
 		// Find bits for this word.
@@ -414,26 +408,28 @@ scanobject(byte *b, uintptr n, byte *ptrmask, Workbuf *wbuf)
 				runtime·mheap.spans[(b-arena_start)>>PageShift] != runtime·mheap.spans[(b+i-arena_start)>>PageShift])
 				break;
 			// Consult GC bitmap.
-			if(ncached <= 0) {
-				// Refill cache.
-				cached = *--ptrbitp;
-				ncached = 2;
-			}
-			bits = cached;
-			cached >>= gcBits;
-			ncached--;
-			
-			if((bits&bitBoundary) != 0)
+			bits = *ptrbitp;
+			if(wordsPerBitmapByte != 2)
+				runtime·throw("alg doesn't work for wordsPerBitmapByte != 2");
+			j = ((uintptr)b+i)/PtrSize & 1;
+			bits >>= gcBits*j;
+			if(i == 0)
+				bits &= ~bitBoundary;
+			ptrbitp -= j;
+		
+			if((bits&bitBoundary) != 0 && i != 0)
 				break; // reached beginning of the next object
 			bits = (bits>>2)&BitsMask;
 			if(bits == BitsDead)
 				break; // reached no-scan part of the object
 		} 
 
-		if(bits == BitsScalar || bits == BitsDead)
+		if(bits <= BitsScalar) // Bits Scalar || BitsDead
 			continue;
-		if(bits != BitsPointer)
+		if(bits != BitsPointer) {
+			runtime·printf("gc bits=%x\n", bits);
 			runtime·throw("unexpected garbage collection bits");
+		}
 
 		obj = *(byte**)(b+i);
 		// At this point we have extracted the next potential pointer.
@@ -1608,6 +1604,8 @@ gc(struct gc_args *args)
 	if(runtime·work.nproc > 1)
 		runtime·notesleep(&runtime·work.alldone);
 
+	runtime·shrinkfinish();
+
 	cachestats();
 	// next_gc calculation is tricky with concurrent sweep since we don't know size of live heap
 	// estimate what was live heap size after previous GC (for tracing only)
diff --git a/src/runtime/mgc0.go b/src/runtime/mgc0.go
index 0e17599c2..3a7204b54 100644
--- a/src/runtime/mgc0.go
+++ b/src/runtime/mgc0.go
@@ -110,6 +110,27 @@ func writebarrieriface(dst *[2]uintptr, src [2]uintptr) {
 }
 
 //go:nosplit
+func writebarrierfat2(dst *[2]uintptr, _ *byte, src [2]uintptr) {
+	dst[0] = src[0]
+	dst[1] = src[1]
+}
+
+//go:nosplit
+func writebarrierfat3(dst *[3]uintptr, _ *byte, src [3]uintptr) {
+	dst[0] = src[0]
+	dst[1] = src[1]
+	dst[2] = src[2]
+}
+
+//go:nosplit
+func writebarrierfat4(dst *[4]uintptr, _ *byte, src [4]uintptr) {
+	dst[0] = src[0]
+	dst[1] = src[1]
+	dst[2] = src[2]
+	dst[3] = src[3]
+}
+
+//go:nosplit
 func writebarrierfat(typ *_type, dst, src unsafe.Pointer) {
 	memmove(dst, src, typ.size)
 }
diff --git a/src/runtime/mgc0.h b/src/runtime/mgc0.h
index 10f24d009..64f818914 100644
--- a/src/runtime/mgc0.h
+++ b/src/runtime/mgc0.h
@@ -42,6 +42,8 @@ enum {
 	BitsMask	= (1<<BitsPerPointer)-1,
 	PointersPerByte	= 8/BitsPerPointer,
 
+	// If you change these, also change scanblock.
+	// scanblock does "if(bits == BitsScalar || bits == BitsDead)" as "if(bits <= BitsScalar)".
 	BitsDead	= 0,
 	BitsScalar	= 1,
 	BitsPointer	= 2,
diff --git a/src/runtime/os_windows.c b/src/runtime/os_windows.c
index 77f99062c..b8b8eda5f 100644
--- a/src/runtime/os_windows.c
+++ b/src/runtime/os_windows.c
@@ -34,6 +34,7 @@
 #pragma dynimport runtime·SetEvent SetEvent "kernel32.dll"
 #pragma dynimport runtime·SetProcessPriorityBoost SetProcessPriorityBoost "kernel32.dll"
 #pragma dynimport runtime·SetThreadPriority SetThreadPriority "kernel32.dll"
+#pragma dynimport runtime·SetUnhandledExceptionFilter SetUnhandledExceptionFilter "kernel32.dll"
 #pragma dynimport runtime·SetWaitableTimer SetWaitableTimer "kernel32.dll"
 #pragma dynimport runtime·Sleep Sleep "kernel32.dll"
 #pragma dynimport runtime·SuspendThread SuspendThread "kernel32.dll"
@@ -65,6 +66,7 @@ extern void *runtime·SetConsoleCtrlHandler;
 extern void *runtime·SetEvent;
 extern void *runtime·SetProcessPriorityBoost;
 extern void *runtime·SetThreadPriority;
+extern void *runtime·SetUnhandledExceptionFilter;
 extern void *runtime·SetWaitableTimer;
 extern void *runtime·Sleep;
 extern void *runtime·SuspendThread;
@@ -77,7 +79,9 @@ void *runtime·GetQueuedCompletionStatusEx;
 
 extern uintptr runtime·externalthreadhandlerp;
 void runtime·externalthreadhandler(void);
-void runtime·sigtramp(void);
+void runtime·exceptiontramp(void);
+void runtime·firstcontinuetramp(void);
+void runtime·lastcontinuetramp(void);
 
 #pragma textflag NOSPLIT
 uintptr
@@ -106,12 +110,30 @@ void
 runtime·osinit(void)
 {
 	void *kernel32;
+	void *addVectoredContinueHandler;
+
+	kernel32 = runtime·stdcall1(runtime·LoadLibraryA, (uintptr)"kernel32.dll");
 
 	runtime·externalthreadhandlerp = (uintptr)runtime·externalthreadhandler;
 
-	runtime·stdcall2(runtime·AddVectoredExceptionHandler, 1, (uintptr)runtime·sigtramp);
+	runtime·stdcall2(runtime·AddVectoredExceptionHandler, 1, (uintptr)runtime·exceptiontramp);
+	addVectoredContinueHandler = nil;
+	if(kernel32 != nil)
+		addVectoredContinueHandler = runtime·stdcall2(runtime·GetProcAddress, (uintptr)kernel32, (uintptr)"AddVectoredContinueHandler");
+	if(addVectoredContinueHandler == nil || sizeof(void*) == 4) {
+		// use SetUnhandledExceptionFilter for windows-386 or
+		// if VectoredContinueHandler is unavailable.
+		// note: SetUnhandledExceptionFilter handler won't be called, if debugging.
+		runtime·stdcall1(runtime·SetUnhandledExceptionFilter, (uintptr)runtime·lastcontinuetramp);
+	} else {
+		runtime·stdcall2(addVectoredContinueHandler, 1, (uintptr)runtime·firstcontinuetramp);
+		runtime·stdcall2(addVectoredContinueHandler, 0, (uintptr)runtime·lastcontinuetramp);
+	}
+
 	runtime·stdcall2(runtime·SetConsoleCtrlHandler, (uintptr)runtime·ctrlhandler, 1);
+
 	runtime·stdcall1(runtime·timeBeginPeriod, 1);
+
 	runtime·ncpu = getproccount();
 	
 	// Windows dynamic priority boosting assumes that a process has different types
@@ -120,7 +142,6 @@ runtime·osinit(void)
 	// In such context dynamic priority boosting does nothing but harm, so we turn it off.
 	runtime·stdcall2(runtime·SetProcessPriorityBoost, -1, 1);
 
-	kernel32 = runtime·stdcall1(runtime·LoadLibraryA, (uintptr)"kernel32.dll");
 	if(kernel32 != nil) {
 		runtime·GetQueuedCompletionStatusEx = runtime·stdcall2(runtime·GetProcAddress, (uintptr)kernel32, (uintptr)"GetQueuedCompletionStatusEx");
 	}
@@ -268,19 +289,19 @@ runtime·mpreinit(M *mp)
 void
 runtime·minit(void)
 {
-	void *thandle;
+	uintptr thandle;
 
 	// -1 = current process, -2 = current thread
 	runtime·stdcall7(runtime·DuplicateHandle, -1, -2, -1, (uintptr)&thandle, 0, 0, DUPLICATE_SAME_ACCESS);
-	runtime·atomicstorep(&g->m->thread, thandle);
+	runtime·atomicstoreuintptr(&g->m->thread, thandle);
 }
 
 // Called from dropm to undo the effect of an minit.
 void
 runtime·unminit(void)
 {
-	runtime·stdcall1(runtime·CloseHandle, (uintptr)g->m->thread);
-	g->m->thread = nil;
+	runtime·stdcall1(runtime·CloseHandle, g->m->thread);
+	g->m->thread = 0;
 }
 
 // Described in http://www.dcl.hpi.uni-potsdam.de/research/WRK/2007/08/getting-os-information-the-kuser_shared_data-structure/
@@ -467,6 +488,7 @@ runtime·issigpanic(uint32 code)
 	case EXCEPTION_FLT_INEXACT_RESULT:
 	case EXCEPTION_FLT_OVERFLOW:
 	case EXCEPTION_FLT_UNDERFLOW:
+	case EXCEPTION_BREAKPOINT:
 		return 1;
 	}
 	return 0;
@@ -475,10 +497,14 @@ runtime·issigpanic(uint32 code)
 void
 runtime·initsig(void)
 {
-	// following line keeps sigtramp alive at link stage
+	// following line keeps these functions alive at link stage
 	// if there's a better way please write it here
-	void *p = runtime·sigtramp;
-	USED(p);
+	void *e = runtime·exceptiontramp;
+	void *f = runtime·firstcontinuetramp;
+	void *l = runtime·lastcontinuetramp;
+	USED(e);
+	USED(f);
+	USED(l);
 }
 
 uint32
@@ -532,7 +558,7 @@ void
 runtime·profileloop1(void)
 {
 	M *mp, *allm;
-	void *thread;
+	uintptr thread;
 
 	runtime·stdcall2(runtime·SetThreadPriority, -2, THREAD_PRIORITY_HIGHEST);
 
@@ -540,11 +566,11 @@ runtime·profileloop1(void)
 		runtime·stdcall2(runtime·WaitForSingleObject, (uintptr)profiletimer, -1);
 		allm = runtime·atomicloadp(&runtime·allm);
 		for(mp = allm; mp != nil; mp = mp->alllink) {
-			thread = runtime·atomicloadp(&mp->thread);
+			thread = runtime·atomicloaduintptr(&mp->thread);
 			// Do not profile threads blocked on Notes,
 			// this includes idle worker threads,
 			// idle timer thread, idle heap scavenger, etc.
-			if(thread == nil || mp->profilehz == 0 || mp->blocked)
+			if(thread == 0 || mp->profilehz == 0 || mp->blocked)
 				continue;
 			runtime·stdcall1(runtime·SuspendThread, (uintptr)thread);
 			if(mp->profilehz != 0 && !mp->blocked)
diff --git a/src/runtime/os_windows_386.c b/src/runtime/os_windows_386.c
index e2ae8db27..213582799 100644
--- a/src/runtime/os_windows_386.c
+++ b/src/runtime/os_windows_386.c
@@ -24,45 +24,63 @@ runtime·dumpregs(Context *r)
 	runtime·printf("gs      %x\n", r->SegGs);
 }
 
-// Called by sigtramp from Windows VEH handler.
-// Return value signals whether the exception has been handled (-1)
-// or should be made available to other handlers in the chain (0).
-uint32
-runtime·sighandler(ExceptionRecord *info, Context *r, G *gp)
+bool
+runtime·isgoexception(ExceptionRecord *info, Context *r)
 {
-	bool crash;
-	uintptr *sp;
 	extern byte runtime·text[], runtime·etext[];
 
 	// Only handle exception if executing instructions in Go binary
 	// (not Windows library code). 
 	if(r->Eip < (uint32)runtime·text || (uint32)runtime·etext < r->Eip)
-		return 0;
-
-	if(gp != nil && runtime·issigpanic(info->ExceptionCode)) {
-		// Make it look like a call to the signal func.
-		// Have to pass arguments out of band since
-		// augmenting the stack frame would break
-		// the unwinding code.
-		gp->sig = info->ExceptionCode;
-		gp->sigcode0 = info->ExceptionInformation[0];
-		gp->sigcode1 = info->ExceptionInformation[1];
-		gp->sigpc = r->Eip;
-
-		// Only push runtime·sigpanic if r->eip != 0.
-		// If r->eip == 0, probably panicked because of a
-		// call to a nil func.  Not pushing that onto sp will
-		// make the trace look like a call to runtime·sigpanic instead.
-		// (Otherwise the trace will end at runtime·sigpanic and we
-		// won't get to see who faulted.)
-		if(r->Eip != 0) {
-			sp = (uintptr*)r->Esp;
-			*--sp = r->Eip;
-			r->Esp = (uintptr)sp;
-		}
-		r->Eip = (uintptr)runtime·sigpanic;
-		return -1;
+		return false;
+
+	if(!runtime·issigpanic(info->ExceptionCode))
+		return false;
+
+	return true;
+}
+
+// Called by sigtramp from Windows VEH handler.
+// Return value signals whether the exception has been handled (EXCEPTION_CONTINUE_EXECUTION)
+// or should be made available to other handlers in the chain (EXCEPTION_CONTINUE_SEARCH).
+uint32
+runtime·exceptionhandler(ExceptionRecord *info, Context *r, G *gp)
+{
+	uintptr *sp;
+
+	if(!runtime·isgoexception(info, r))
+		return EXCEPTION_CONTINUE_SEARCH;
+
+	// Make it look like a call to the signal func.
+	// Have to pass arguments out of band since
+	// augmenting the stack frame would break
+	// the unwinding code.
+	gp->sig = info->ExceptionCode;
+	gp->sigcode0 = info->ExceptionInformation[0];
+	gp->sigcode1 = info->ExceptionInformation[1];
+	gp->sigpc = r->Eip;
+
+	// Only push runtime·sigpanic if r->eip != 0.
+	// If r->eip == 0, probably panicked because of a
+	// call to a nil func.  Not pushing that onto sp will
+	// make the trace look like a call to runtime·sigpanic instead.
+	// (Otherwise the trace will end at runtime·sigpanic and we
+	// won't get to see who faulted.)
+	if(r->Eip != 0) {
+		sp = (uintptr*)r->Esp;
+		*--sp = r->Eip;
+		r->Esp = (uintptr)sp;
 	}
+	r->Eip = (uintptr)runtime·sigpanic;
+	return EXCEPTION_CONTINUE_EXECUTION;
+}
+
+// lastcontinuehandler is reached, because runtime cannot handle
+// current exception. lastcontinuehandler will print crash info and exit.
+uint32
+runtime·lastcontinuehandler(ExceptionRecord *info, Context *r, G *gp)
+{
+	bool crash;
 
 	if(runtime·panicking)	// traceback already printed
 		runtime·exit(2);
@@ -88,7 +106,7 @@ runtime·sighandler(ExceptionRecord *info, Context *r, G *gp)
 		runtime·crash();
 
 	runtime·exit(2);
-	return -1; // not reached
+	return 0; // not reached
 }
 
 void
diff --git a/src/runtime/os_windows_amd64.c b/src/runtime/os_windows_amd64.c
index 261880d45..b96cf70d1 100644
--- a/src/runtime/os_windows_amd64.c
+++ b/src/runtime/os_windows_amd64.c
@@ -32,45 +32,76 @@ runtime·dumpregs(Context *r)
 	runtime·printf("gs      %X\n", (uint64)r->SegGs);
 }
 
-// Called by sigtramp from Windows VEH handler.
-// Return value signals whether the exception has been handled (-1)
-// or should be made available to other handlers in the chain (0).
-uint32
-runtime·sighandler(ExceptionRecord *info, Context *r, G *gp)
+bool
+runtime·isgoexception(ExceptionRecord *info, Context *r)
 {
-	bool crash;
-	uintptr *sp;
 	extern byte runtime·text[], runtime·etext[];
 
 	// Only handle exception if executing instructions in Go binary
 	// (not Windows library code). 
 	if(r->Rip < (uint64)runtime·text || (uint64)runtime·etext < r->Rip)
-		return 0;
-
-	if(gp != nil && runtime·issigpanic(info->ExceptionCode)) {
-		// Make it look like a call to the signal func.
-		// Have to pass arguments out of band since
-		// augmenting the stack frame would break
-		// the unwinding code.
-		gp->sig = info->ExceptionCode;
-		gp->sigcode0 = info->ExceptionInformation[0];
-		gp->sigcode1 = info->ExceptionInformation[1];
-		gp->sigpc = r->Rip;
-
-		// Only push runtime·sigpanic if r->rip != 0.
-		// If r->rip == 0, probably panicked because of a
-		// call to a nil func.  Not pushing that onto sp will
-		// make the trace look like a call to runtime·sigpanic instead.
-		// (Otherwise the trace will end at runtime·sigpanic and we
-		// won't get to see who faulted.)
-		if(r->Rip != 0) {
-			sp = (uintptr*)r->Rsp;
-			*--sp = r->Rip;
-			r->Rsp = (uintptr)sp;
-		}
-		r->Rip = (uintptr)runtime·sigpanic;
-		return -1;
+		return false;
+
+	if(!runtime·issigpanic(info->ExceptionCode))
+		return false;
+
+	return true;
+}
+
+// Called by sigtramp from Windows VEH handler.
+// Return value signals whether the exception has been handled (EXCEPTION_CONTINUE_EXECUTION)
+// or should be made available to other handlers in the chain (EXCEPTION_CONTINUE_SEARCH).
+uint32
+runtime·exceptionhandler(ExceptionRecord *info, Context *r, G *gp)
+{
+	uintptr *sp;
+
+	if(!runtime·isgoexception(info, r))
+		return EXCEPTION_CONTINUE_SEARCH;
+
+	// Make it look like a call to the signal func.
+	// Have to pass arguments out of band since
+	// augmenting the stack frame would break
+	// the unwinding code.
+	gp->sig = info->ExceptionCode;
+	gp->sigcode0 = info->ExceptionInformation[0];
+	gp->sigcode1 = info->ExceptionInformation[1];
+	gp->sigpc = r->Rip;
+
+	// Only push runtime·sigpanic if r->rip != 0.
+	// If r->rip == 0, probably panicked because of a
+	// call to a nil func.  Not pushing that onto sp will
+	// make the trace look like a call to runtime·sigpanic instead.
+	// (Otherwise the trace will end at runtime·sigpanic and we
+	// won't get to see who faulted.)
+	if(r->Rip != 0) {
+		sp = (uintptr*)r->Rsp;
+		*--sp = r->Rip;
+		r->Rsp = (uintptr)sp;
 	}
+	r->Rip = (uintptr)runtime·sigpanic;
+	return EXCEPTION_CONTINUE_EXECUTION;
+}
+
+// It seems Windows searches ContinueHandler's list even
+// if ExceptionHandler returns EXCEPTION_CONTINUE_EXECUTION.
+// firstcontinuehandler will stop that search,
+// if exceptionhandler did the same earlier.
+uint32
+runtime·firstcontinuehandler(ExceptionRecord *info, Context *r, G *gp)
+{
+	USED(gp);
+	if(!runtime·isgoexception(info, r))
+		return EXCEPTION_CONTINUE_SEARCH;
+	return EXCEPTION_CONTINUE_EXECUTION;
+}
+
+// lastcontinuehandler is reached, because runtime cannot handle
+// current exception. lastcontinuehandler will print crash info and exit.
+uint32
+runtime·lastcontinuehandler(ExceptionRecord *info, Context *r, G *gp)
+{
+	bool crash;
 
 	if(runtime·panicking)	// traceback already printed
 		runtime·exit(2);
@@ -97,7 +128,7 @@ runtime·sighandler(ExceptionRecord *info, Context *r, G *gp)
 		runtime·crash();
 
 	runtime·exit(2);
-	return -1; // not reached
+	return 0; // not reached
 }
 
 void
diff --git a/src/runtime/panic.c b/src/runtime/panic.c
index 1cd0aa865..24eb6dbfe 100644
--- a/src/runtime/panic.c
+++ b/src/runtime/panic.c
@@ -31,8 +31,11 @@ runtime·deferproc_m(void)
 	argp = g->m->scalararg[1];
 	callerpc = g->m->scalararg[2];
 	g->m->ptrarg[0] = nil;
+	g->m->scalararg[1] = 0;
 
 	d = runtime·newdefer(siz);
+	if(d->panic != nil)
+		runtime·throw("deferproc: d->panic != nil after newdefer");
 	d->fn = fn;
 	d->pc = callerpc;
 	d->argp = argp;
@@ -131,6 +134,7 @@ runtime·dopanic_m(void)
 	g->m->ptrarg[0] = nil;
 	pc = g->m->scalararg[0];
 	sp = g->m->scalararg[1];
+	g->m->scalararg[1] = 0;
 	if(gp->sig != 0)
 		runtime·printf("[signal %x code=%p addr=%p pc=%p]\n",
 			gp->sig, gp->sigcode0, gp->sigcode1, gp->sigpc);
diff --git a/src/runtime/panic.go b/src/runtime/panic.go
index 7eb2d6055..685ff5ca0 100644
--- a/src/runtime/panic.go
+++ b/src/runtime/panic.go
@@ -188,6 +188,12 @@ func newdefer(siz int32) *_defer {
 // The defer cannot be used after this call.
 //go:nosplit
 func freedefer(d *_defer) {
+	if d._panic != nil {
+		freedeferpanic()
+	}
+	if d.fn != nil {
+		freedeferfn()
+	}
 	sc := deferclass(uintptr(d.siz))
 	if sc < uintptr(len(p{}.deferpool)) {
 		mp := acquirem()
@@ -199,6 +205,18 @@ func freedefer(d *_defer) {
 	}
 }
 
+// Separate function so that it can split stack.
+// Windows otherwise runs out of stack space.
+func freedeferpanic() {
+	// _panic must be cleared before d is unlinked from gp.
+	gothrow("freedefer with d._panic != nil")
+}
+
+func freedeferfn() {
+	// fn must be cleared before d is unlinked from gp.
+	gothrow("freedefer with d.fn != nil")
+}
+
 // Run a deferred function if there is one.
 // The compiler inserts a call to this at the end of any
 // function which calls defer.
@@ -231,6 +249,7 @@ func deferreturn(arg0 uintptr) {
 	mp := acquirem()
 	memmove(unsafe.Pointer(argp), deferArgs(d), uintptr(d.siz))
 	fn := d.fn
+	d.fn = nil
 	gp._defer = d.link
 	freedefer(d)
 	releasem(mp)
@@ -258,7 +277,9 @@ func Goexit() {
 		if d.started {
 			if d._panic != nil {
 				d._panic.aborted = true
+				d._panic = nil
 			}
+			d.fn = nil
 			gp._defer = d.link
 			freedefer(d)
 			continue
@@ -268,6 +289,8 @@ func Goexit() {
 		if gp._defer != d {
 			gothrow("bad defer entry in Goexit")
 		}
+		d._panic = nil
+		d.fn = nil
 		gp._defer = d.link
 		freedefer(d)
 		// Note: we ignore recovers here because Goexit isn't a panic
@@ -343,6 +366,8 @@ func gopanic(e interface{}) {
 			if d._panic != nil {
 				d._panic.aborted = true
 			}
+			d._panic = nil
+			d.fn = nil
 			gp._defer = d.link
 			freedefer(d)
 			continue
@@ -366,6 +391,8 @@ func gopanic(e interface{}) {
 		if gp._defer != d {
 			gothrow("bad defer entry in panic")
 		}
+		d._panic = nil
+		d.fn = nil
 		gp._defer = d.link
 
 		// trigger shrinkage to test stack copy.  See stack_test.go:TestStackPanic
diff --git a/src/runtime/runtime.h b/src/runtime/runtime.h
index 609ae9406..bea773799 100644
--- a/src/runtime/runtime.h
+++ b/src/runtime/runtime.h
@@ -372,7 +372,7 @@ struct	M
 	uintptr scalararg[4];	// scalar argument/return for mcall
 	void*   ptrarg[4];	// pointer argument/return for mcall
 #ifdef GOOS_windows
-	void*	thread;		// thread handle
+	uintptr	thread;		// thread handle
 	// these are here because they are too large to be on the stack
 	// of low-level NOSPLIT functions.
 	LibCall	libcall;
@@ -865,6 +865,7 @@ void	runtime·stackinit(void);
 Stack	runtime·stackalloc(uint32);
 void	runtime·stackfree(Stack);
 void	runtime·shrinkstack(G*);
+void	runtime·shrinkfinish(void);
 MCache*	runtime·allocmcache(void);
 void	runtime·freemcache(MCache*);
 void	runtime·mallocinit(void);
@@ -898,7 +899,9 @@ void	runtime·atomicstore(uint32 volatile*, uint32);
 void	runtime·atomicstore64(uint64 volatile*, uint64);
 uint64	runtime·atomicload64(uint64 volatile*);
 void*	runtime·atomicloadp(void* volatile*);
+uintptr	runtime·atomicloaduintptr(uintptr volatile*);
 void	runtime·atomicstorep(void* volatile*, void*);
+void	runtime·atomicstoreuintptr(uintptr volatile*, uintptr);
 void	runtime·atomicor8(byte volatile*, byte);
 
 void	runtime·setg(G*);
diff --git a/src/runtime/stack.c b/src/runtime/stack.c
index 8562b9407..e402691f4 100644
--- a/src/runtime/stack.c
+++ b/src/runtime/stack.c
@@ -36,6 +36,8 @@ MSpan runtime·stackpool[NumStackOrders];
 Mutex runtime·stackpoolmu;
 // TODO: one lock per order?
 
+static Stack stackfreequeue;
+
 void
 runtime·stackinit(void)
 {
@@ -656,7 +658,24 @@ copystack(G *gp, uintptr newsize)
 		while(p < ep)
 			*p++ = 0xfc;
 	}
-	runtime·stackfree(old);
+	if(newsize > old.hi-old.lo) {
+		// growing, free stack immediately
+		runtime·stackfree(old);
+	} else {
+		// shrinking, queue up free operation.  We can't actually free the stack
+		// just yet because we might run into the following situation:
+		// 1) GC starts, scans a SudoG but does not yet mark the SudoG.elem pointer
+		// 2) The stack that pointer points to is shrunk
+		// 3) The old stack is freed
+		// 4) The containing span is marked free
+		// 5) GC attempts to mark the SudoG.elem pointer.  The marking fails because
+		//    the pointer looks like a pointer into a free span.
+		// By not freeing, we prevent step #4 until GC is done.
+		runtime·lock(&runtime·stackpoolmu);
+		*(Stack*)old.lo = stackfreequeue;
+		stackfreequeue = old;
+		runtime·unlock(&runtime·stackpoolmu);
+	}
 }
 
 // round x up to a power of 2.
@@ -706,6 +725,7 @@ runtime·newstack(void)
 	g->m->morebuf.pc = (uintptr)nil;
 	g->m->morebuf.lr = (uintptr)nil;
 	g->m->morebuf.sp = (uintptr)nil;
+	g->m->morebuf.g = (G*)nil;
 
 	runtime·casgstatus(gp, Grunning, Gwaiting);
 	gp->waitreason = runtime·gostringnocopy((byte*)"stack growth");
@@ -841,6 +861,23 @@ runtime·shrinkstack(G *gp)
 	copystack(gp, newsize);
 }
 
+// Do any delayed stack freeing that was queued up during GC.
+void
+runtime·shrinkfinish(void)
+{
+	Stack s, t;
+
+	runtime·lock(&runtime·stackpoolmu);
+	s = stackfreequeue;
+	stackfreequeue = (Stack){0,0};
+	runtime·unlock(&runtime·stackpoolmu);
+	while(s.lo != 0) {
+		t = *(Stack*)s.lo;
+		runtime·stackfree(s);
+		s = t;
+	}
+}
+
 static void badc(void);
 
 #pragma textflag NOSPLIT
diff --git a/src/runtime/stubs.go b/src/runtime/stubs.go
index c6a9cf9f5..6561094ff 100644
--- a/src/runtime/stubs.go
+++ b/src/runtime/stubs.go
@@ -252,3 +252,33 @@ func return0()
 
 // thunk to call time.now.
 func timenow() (sec int64, nsec int32)
+
+// in asm_*.s
+// not called directly; definitions here supply type information for traceback.
+func call16(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call32(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call64(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call128(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call256(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call512(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call1024(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call2048(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call4096(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call8192(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call16384(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call32768(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call65536(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call131072(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call262144(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call524288(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call1048576(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call2097152(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call4194304(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call8388608(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call16777216(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call33554432(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call67108864(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call134217728(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call268435456(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call536870912(fn, arg unsafe.Pointer, n, retoffset uint32)
+func call1073741824(fn, arg unsafe.Pointer, n, retoffset uint32)
diff --git a/src/runtime/sys_windows_386.s b/src/runtime/sys_windows_386.s
index 1bf4d062a..932fe9dd2 100644
--- a/src/runtime/sys_windows_386.s
+++ b/src/runtime/sys_windows_386.s
@@ -73,6 +73,7 @@ TEXT runtime·setlasterror(SB),NOSPLIT,$0
 // Called by Windows as a Vectored Exception Handler (VEH).
 // First argument is pointer to struct containing
 // exception record and context pointers.
+// Handler function is stored in AX.
 // Return 0 for 'not handled', -1 for handled.
 TEXT runtime·sigtramp(SB),NOSPLIT,$0-0
 	MOVL	ptrs+0(FP), CX
@@ -84,6 +85,8 @@ TEXT runtime·sigtramp(SB),NOSPLIT,$0-0
 	MOVL	SI, 20(SP)
 	MOVL	DI, 24(SP)
 
+	MOVL	AX, SI	// save handler address
+
 	// find g
 	get_tls(DX)
 	CMPL	DX, $0
@@ -123,11 +126,10 @@ TEXT runtime·sigtramp(SB),NOSPLIT,$0-0
 sigtramp_g0:
 	MOVL	0(CX), BX // ExceptionRecord*
 	MOVL	4(CX), CX // Context*
-	// call sighandler(ExceptionRecord*, Context*, G*)
 	MOVL	BX, 0(SP)
 	MOVL	CX, 4(SP)
 	MOVL	DX, 8(SP)
-	CALL	runtime·sighandler(SB)
+	CALL	SI	// call handler
 	// AX is set to report result back to Windows
 	MOVL	12(SP), AX
 
@@ -149,6 +151,18 @@ done:
 	// RET 4 (return and pop 4 bytes parameters)
 	BYTE $0xC2; WORD $4
 	RET // unreached; make assembler happy
+ 
+TEXT runtime·exceptiontramp(SB),NOSPLIT,$0
+	MOVL	$runtime·exceptionhandler(SB), AX
+	JMP	runtime·sigtramp(SB)
+
+TEXT runtime·firstcontinuetramp(SB),NOSPLIT,$0-0
+	// is never called
+	INT	$3
+
+TEXT runtime·lastcontinuetramp(SB),NOSPLIT,$0-0
+	MOVL	$runtime·lastcontinuehandler(SB), AX
+	JMP	runtime·sigtramp(SB)
 
 TEXT runtime·ctrlhandler(SB),NOSPLIT,$0
 	PUSHL	$runtime·ctrlhandler1(SB)
diff --git a/src/runtime/sys_windows_amd64.s b/src/runtime/sys_windows_amd64.s
index 05750398e..e6190ce68 100644
--- a/src/runtime/sys_windows_amd64.s
+++ b/src/runtime/sys_windows_amd64.s
@@ -99,6 +99,7 @@ TEXT runtime·setlasterror(SB),NOSPLIT,$0
 // Called by Windows as a Vectored Exception Handler (VEH).
 // First argument is pointer to struct containing
 // exception record and context pointers.
+// Handler function is stored in AX.
 // Return 0 for 'not handled', -1 for handled.
 TEXT runtime·sigtramp(SB),NOSPLIT,$0-0
 	// CX: PEXCEPTION_POINTERS ExceptionInfo
@@ -116,6 +117,8 @@ TEXT runtime·sigtramp(SB),NOSPLIT,$0-0
 	MOVQ	R14, 32(SP)
 	MOVQ	R15, 88(SP)
 
+	MOVQ	AX, R15	// save handler address
+
 	// find g
 	get_tls(DX)
 	CMPQ	DX, $0
@@ -157,11 +160,10 @@ TEXT runtime·sigtramp(SB),NOSPLIT,$0-0
 sigtramp_g0:
 	MOVQ	0(CX), BX // ExceptionRecord*
 	MOVQ	8(CX), CX // Context*
-	// call sighandler(ExceptionRecord*, Context*, G*)
 	MOVQ	BX, 0(SP)
 	MOVQ	CX, 8(SP)
 	MOVQ	DX, 16(SP)
-	CALL	runtime·sighandler(SB)
+	CALL	R15	// call handler
 	// AX is set to report result back to Windows
 	MOVL	24(SP), AX
 
@@ -187,6 +189,18 @@ done:
 
 	RET
 
+TEXT runtime·exceptiontramp(SB),NOSPLIT,$0
+	MOVQ	$runtime·exceptionhandler(SB), AX
+	JMP	runtime·sigtramp(SB)
+
+TEXT runtime·firstcontinuetramp(SB),NOSPLIT,$0-0
+	MOVQ	$runtime·firstcontinuehandler(SB), AX
+	JMP	runtime·sigtramp(SB)
+
+TEXT runtime·lastcontinuetramp(SB),NOSPLIT,$0-0
+	MOVQ	$runtime·lastcontinuehandler(SB), AX
+	JMP	runtime·sigtramp(SB)
+
 TEXT runtime·ctrlhandler(SB),NOSPLIT,$8
 	MOVQ	CX, 16(SP)		// spill
 	MOVQ	$runtime·ctrlhandler1(SB), CX
diff --git a/src/runtime/syscall_windows_test.go b/src/runtime/syscall_windows_test.go
index 9ed016ccc..ce8a9ec1b 100644
--- a/src/runtime/syscall_windows_test.go
+++ b/src/runtime/syscall_windows_test.go
@@ -494,3 +494,42 @@ func TestOutputDebugString(t *testing.T) {
 	p := syscall.StringToUTF16Ptr("testing OutputDebugString")
 	d.Proc("OutputDebugStringW").Call(uintptr(unsafe.Pointer(p)))
 }
+
+func TestRaiseException(t *testing.T) {
+	o := executeTest(t, raiseExceptionSource, nil)
+	if strings.Contains(o, "RaiseException should not return") {
+		t.Fatalf("RaiseException did not crash program: %v", o)
+	}
+	if !strings.Contains(o, "Exception 0xbad") {
+		t.Fatalf("No stack trace: %v", o)
+	}
+}
+
+const raiseExceptionSource = `
+package main
+import "syscall"
+func main() {
+	const EXCEPTION_NONCONTINUABLE = 1
+	mod := syscall.MustLoadDLL("kernel32.dll")
+	proc := mod.MustFindProc("RaiseException")
+	proc.Call(0xbad, EXCEPTION_NONCONTINUABLE, 0, 0)
+	println("RaiseException should not return")
+}
+`
+
+func TestZeroDivisionException(t *testing.T) {
+	o := executeTest(t, zeroDivisionExceptionSource, nil)
+	if !strings.Contains(o, "panic: runtime error: integer divide by zero") {
+		t.Fatalf("No stack trace: %v", o)
+	}
+}
+
+const zeroDivisionExceptionSource = `
+package main
+func main() {
+	x := 1
+	y := 0
+	z := x / y
+	println(z)
+}
+`
diff --git a/src/runtime/type.h b/src/runtime/type.h
index de82e886f..f5b4f9d13 100644
--- a/src/runtime/type.h
+++ b/src/runtime/type.h
@@ -23,7 +23,7 @@ struct Type
 	uint8 kind;
 	void* alg;
 	// gc stores type info required for garbage collector.
-	// If (kind&KindGCProg)==0, then gc directly contains sparse GC bitmap
+	// If (kind&KindGCProg)==0, then gc[0] points at sparse GC bitmap
 	// (no indirection), 4 bits per word.
 	// If (kind&KindGCProg)!=0, then gc[1] points to a compiler-generated
 	// read-only GC program; and gc[0] points to BSS space for sparse GC bitmap.
diff --git a/src/strings/strings.go b/src/strings/strings.go
index 1b9df2e75..27d384983 100644
--- a/src/strings/strings.go
+++ b/src/strings/strings.go
@@ -225,13 +225,8 @@ func LastIndex(s, sep string) int {
 // r, or -1 if rune is not present in s.
 func IndexRune(s string, r rune) int {
 	switch {
-	case r < 0x80:
-		b := byte(r)
-		for i := 0; i < len(s); i++ {
-			if s[i] == b {
-				return i
-			}
-		}
+	case r < utf8.RuneSelf:
+		return IndexByte(s, byte(r))
 	default:
 		for i, c := range s {
 			if c == r {
diff --git a/src/syscall/syscall_windows.go b/src/syscall/syscall_windows.go
index bda8214c3..e89fd096a 100644
--- a/src/syscall/syscall_windows.go
+++ b/src/syscall/syscall_windows.go
@@ -468,7 +468,7 @@ func Utimes(path string, tv []Timeval) (err error) {
 	}
 	h, e := CreateFile(pathp,
 		FILE_WRITE_ATTRIBUTES, FILE_SHARE_WRITE, nil,
-		OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0)
+		OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, 0)
 	if e != nil {
 		return e
 	}
@@ -488,7 +488,7 @@ func UtimesNano(path string, ts []Timespec) (err error) {
 	}
 	h, e := CreateFile(pathp,
 		FILE_WRITE_ATTRIBUTES, FILE_SHARE_WRITE, nil,
-		OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0)
+		OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, 0)
 	if e != nil {
 		return e
 	}
diff --git a/src/syscall/ztypes_windows.go b/src/syscall/ztypes_windows.go
index 1363da01a..4c8a99ab9 100644
--- a/src/syscall/ztypes_windows.go
+++ b/src/syscall/ztypes_windows.go
@@ -547,6 +547,7 @@ const (
 	IOC_WS2                            = 0x08000000
 	SIO_GET_EXTENSION_FUNCTION_POINTER = IOC_INOUT | IOC_WS2 | 6
 	SIO_KEEPALIVE_VALS                 = IOC_IN | IOC_VENDOR | 4
+	SIO_UDP_CONNRESET                  = IOC_IN | IOC_VENDOR | 12
 
 	// cf. http://support.microsoft.com/default.aspx?scid=kb;en-us;257460