gc: implement append

R=ken2
CC=golang-dev
https://golang.org/cl/2757042

src/cmd/gc/builtin.c.boot

@@ -21,6 +21,8 @@ char *runtimeimport =
 	"func \"\".printsp ()\n"
 	"func \"\".printf ()\n"
 	"func \"\".concatstring ()\n"
+	"func \"\".append ()\n"
+	"func \"\".appendslice (typ *uint8, x any, y []any) any\n"
 	"func \"\".cmpstring (? string, ? string) int\n"
 	"func \"\".slicestring (? string, ? int, ? int) string\n"
 	"func \"\".slicestring1 (? string, ? int) string\n"

src/cmd/gc/go.h

@@ -6,6 +6,8 @@
 #include	<libc.h>
 #include	<bio.h>
 
+#undef OAPPEND
+
 // avoid <ctype.h>
 #undef isblank
 #define isblank goisblank
@@ -349,6 +351,7 @@ enum
 	OADD, OSUB, OOR, OXOR, OADDSTR,
 	OADDR,
 	OANDAND,
+	OAPPEND,
 	OARRAY,
 	OARRAYBYTESTR, OARRAYRUNESTR,
 	OSTRARRAYBYTE, OSTRARRAYRUNE,

src/cmd/gc/lex.c

@@ -1531,6 +1531,7 @@ static	struct
 	"type",		LTYPE,		Txxx,		OXXX,
 	"var",		LVAR,		Txxx,		OXXX,
 
+	"append",		LNAME,		Txxx,		OAPPEND,
 	"cap",		LNAME,		Txxx,		OCAP,
 	"close",	LNAME,		Txxx,		OCLOSE,
 	"closed",	LNAME,		Txxx,		OCLOSED,

src/cmd/gc/print.c

@@ -37,6 +37,7 @@ exprfmt(Fmt *f, Node *n, int prec)
 	}
 
 	switch(n->op) {
+	case OAPPEND:
 	case ONAME:
 	case ONONAME:
 	case OPACK:
@@ -400,6 +401,7 @@ exprfmt(Fmt *f, Node *n, int prec)
 		fmtprint(f, ")");
 		break;
 
+	case OAPPEND:
 	case OCAP:
 	case OCLOSE:
 	case OCLOSED:

src/cmd/gc/runtime.go

@@ -36,6 +36,10 @@ func printf()
 // filled in by compiler: int n, string, string, ...
 func concatstring()
 
+// filled in by compiler: Type*, int n, Slice, ...
+func append()
+func appendslice(typ *byte, x any, y []any) any
+
 func cmpstring(string, string) int
 func slicestring(string, int, int) string
 func slicestring1(string, int) string

src/cmd/gc/subr.c

@@ -810,6 +810,7 @@ goopnames[] =
 	[OANDAND]	= "&&",
 	[OANDNOT]	= "&^",
 	[OAND]		= "&",
+	[OAPPEND]	= "append",
 	[OAS]		= "=",
 	[OAS2]		= "=",
 	[OBREAK]	= "break",

src/cmd/gc/typecheck.c

@@ -730,7 +730,7 @@ reswitch:
 		typecheck(&n->left, Erv | Etype | Ecall);
 		l = n->left;
 		if(l->op == ONAME && l->etype != 0) {
-			if(n->isddd)
+			if(n->isddd && l->etype != OAPPEND)
 				yyerror("invalid use of ... with builtin %#N", l);
 			// builtin: OLEN, OCAP, etc.
 			n->op = l->etype;
@@ -905,6 +905,40 @@ reswitch:
 			ok |= Etop;
 		goto ret;
 
+	case OAPPEND:
+		ok |= Erv;
+		args = n->list;
+		if(args == nil) {
+			yyerror("missing arguments to append");
+			goto error;
+		}
+		typechecklist(args, Erv);
+		if((t = args->n->type) == T)
+			goto error;
+		n->type = t;
+		if(!isslice(t)) {
+			yyerror("first argument to append must be slice; have %lT", t);
+			goto error;
+		}
+		if(n->isddd) {
+			if(args->next == nil) {
+				yyerror("cannot use ... on first argument to append");
+				goto error;
+			}
+			if(args->next->next != nil) {
+				yyerror("too many arguments to append");
+				goto error;
+			}
+			args->next->n = assignconv(args->next->n, t->orig, "append");
+			goto ret;
+		}
+		for(args=args->next; args != nil; args=args->next) {
+			if(args->n->type == T)
+				continue;
+			args->n = assignconv(args->n, t->type, "append");
+		}
+		goto ret;
+
 	case OCOPY:
 		ok |= Etop|Erv;
 		args = n->list;

src/cmd/gc/walk.c

@@ -18,6 +18,7 @@ static	NodeList*	paramstoheap(Type **argin, int out);
 static	NodeList*	reorder1(NodeList*);
 static	NodeList*	reorder3(NodeList*);
 static	Node*	addstr(Node*, NodeList**);
+static	Node*	append(Node*, NodeList**);
 
 static	NodeList*	walkdefstack;
 
@@ -1265,6 +1266,10 @@ walkexpr(Node **np, NodeList **init)
 		}
 		goto ret;
 	
+	case OAPPEND:
+		n = append(n, init);
+		goto ret;
+
 	case OCOPY:
 		if(n->right->type->etype == TSTRING)
 			fn = syslook("slicestringcopy", 1);
@@ -2304,3 +2309,44 @@ addstr(Node *n, NodeList **init)
 	
 	return r;
 }
+
+static Node*
+append(Node *n, NodeList **init)
+{
+	int i, j;
+	Node *f, *r;
+	NodeList *in, *args;
+	
+	if(n->isddd) {
+		f = syslook("appendslice", 1);
+		argtype(f, n->type);
+		argtype(f, n->type->type);
+		argtype(f, n->type);
+		r = mkcall1(f, n->type, init, typename(n->type), n->list->n, n->list->next->n);
+		return r;
+	}
+
+	j = count(n->list) - 1;
+	f = syslook("append", 1);
+	f->type = T;
+	f->ntype = nod(OTFUNC, N, N);
+	in = list1(nod(ODCLFIELD, N, typenod(ptrto(types[TUINT8]))));	// type
+	in = list(in, nod(ODCLFIELD, N, typenod(types[TINT])));	// count
+	in = list(in, nod(ODCLFIELD, N, typenod(n->type)));	// slice
+	for(i=0; i<j; i++)
+		in = list(in, nod(ODCLFIELD, N, typenod(n->type->type)));
+	f->ntype->list = in;
+	f->ntype->rlist = list1(nod(ODCLFIELD, N, typenod(n->type)));
+	
+	args = list1(typename(n->type));
+	args = list(args, nodintconst(j));
+	args = concat(args, n->list);
+	
+	r = nod(OCALL, f, N);
+	r->list = args;
+	typecheck(&r, Erv);
+	walkexpr(&r, init);
+	r->type = n->type;
+
+	return r;
+}

src/pkg/runtime/slice.c

@@ -8,29 +8,20 @@
 
 static	int32	debug	= 0;
 
+static	void	makeslice(SliceType*, int32, int32, Slice*);
+	void	·slicecopy(Slice to, Slice fm, uintptr width, int32 ret);
+
 // see also unsafe·NewArray
 // makeslice(typ *Type, len, cap int64) (ary []any);
 void
 ·makeslice(SliceType *t, int64 len, int64 cap, Slice ret)
 {
-	uintptr size;
-
 	if(len < 0 || (int32)len != len)
 		panicstring("makeslice: len out of range");
 	if(cap < len || (int32)cap != cap || cap > ((uintptr)-1) / t->elem->size)
 		panicstring("makeslice: cap out of range");
 
-	size = cap*t->elem->size;
-
-	ret.len = len;
-	ret.cap = cap;
-
-	if((t->elem->kind&KindNoPointers))
-		ret.array = mallocgc(size, RefNoPointers, 1, 1);
-	else
-		ret.array = mal(size);
-
-	FLUSH(&ret);
+	makeslice(t, len, cap, &ret);
 
 	if(debug) {
 		printf("makeslice(%S, %D, %D); ret=",
@@ -39,6 +30,79 @@ void
 	}
 }
 
+static void
+makeslice(SliceType *t, int32 len, int32 cap, Slice *ret)
+{	
+	uintptr size;
+
+	size = cap*t->elem->size;
+
+	ret->len = len;
+	ret->cap = cap;
+
+	if((t->elem->kind&KindNoPointers))
+		ret->array = mallocgc(size, RefNoPointers, 1, 1);
+	else
+		ret->array = mal(size);
+}
+
+static void appendslice(SliceType*, Slice, Slice, Slice*);
+
+// append(type *Type, n int, old []T, ...,) []T
+#pragma textflag 7
+void
+·append(SliceType *t, int32 n, Slice old, ...)
+{
+	Slice sl;
+	Slice *ret;
+	
+	sl.len = n;
+	sl.array = (byte*)(&old+1);
+	ret = (Slice*)(sl.array + ((t->elem->size*n+sizeof(uintptr)-1) & ~(sizeof(uintptr)-1)));
+	appendslice(t, old, sl, ret);
+}
+
+// appendslice(type *Type, x, y, []T) []T
+void
+·appendslice(SliceType *t, Slice x, Slice y, Slice ret)
+{
+	appendslice(t, x, y, &ret);
+}
+
+static void
+appendslice(SliceType *t, Slice x, Slice y, Slice *ret)
+{
+	Slice newx;
+	int32 m;
+	uintptr w;
+
+	if(x.len+y.len < x.len)
+		throw("append: slice overflow");
+
+	w = t->elem->size;
+	if(x.len+y.len > x.cap) {
+		m = x.cap;
+		if(m == 0)
+			m = y.len;
+		else {
+			do {
+				if(x.len < 1024)
+					m += m;
+				else
+					m += m/4;
+			} while(m < x.len+y.len);
+		}
+		makeslice(t, x.len, m, &newx);
+		memmove(newx.array, x.array, x.len*w);
+		x = newx;
+	}
+	memmove(x.array+x.len*w, y.array, y.len*w);
+	x.len += y.len;
+	*ret = x;
+}
+
+
+
 // sliceslice(old []any, lb uint64, hb uint64, width uint64) (ary []any);
 void
 ·sliceslice(Slice old, uint64 lb, uint64 hb, uint64 width, Slice ret)