gc: generalize dst = append(src,...) inlining to arbitrary src and dst arguments.

R=rsc
CC=golang-dev
https://golang.org/cl/4517057

diff --git a/src/cmd/gc/builtin.c.boot b/src/cmd/gc/builtin.c.boot
index 66b5c205ed3ad5d1125506cf3d6f648fbf6fd775..c9bf501d1bcbea460e1f862248599901a6c36971 100644 (file)
--- a/src/cmd/gc/builtin.c.boot
+++ b/src/cmd/gc/builtin.c.boot
@@ -22,7 +22,6 @@ char *runtimeimport =
        "func \"\".printsp ()\n"
        "func \"\".goprintf ()\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"

diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index 569f16cf0a63e3889387bb62d640c72f9dc0cc68..b3b400556c1f9d3310034dcf5d8d74dd45f1ec44 100644 (file)
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -20,7 +20,6 @@ static        NodeList*       reorder3(NodeList*);
 static Node*   addstr(Node*, NodeList**);
 static Node*   appendslice(Node*, NodeList**);
 static Node*   append(Node*, NodeList**);
-static int     oasappend(Node**, NodeList**);
 
 static NodeList*       walkdefstack;
 
@@ -811,9 +810,6 @@ walkexpr(Node **np, NodeList **init)
                if(oaslit(n, init))
                        goto ret;
 
-               if (oasappend(&n, init))
-                       goto ret;
-
                walkexpr(&n->right, init);
                if(n->left != N && n->right != N) {
                        r = convas(nod(OAS, n->left, n->right), init);
@@ -2381,77 +2377,44 @@ appendslice(Node *n, NodeList **init)
        return mkcall1(f, n->type, init, typename(n->type), n->list->n, n->list->next->n);
 }
 
+// expand append(src, a [, b]* ) to
+//
+//   init {
+//     s := src
+//     const argc = len(args) - 1
+//     if cap(s) - len(s) < argc {
+//          s = growslice(s, argc) 
+//     }
+//     n := len(s)
+//     s = s[:n+argc]
+//     s[n] = a
+//     s[n+1] = b
+//     ...
+//   }
+//   s
 static Node*
 append(Node *n, NodeList **init)
-{
-       int i, j;
-       Node *f, *r;
-       NodeList *in, *args;
-
-       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;
-}
-
-
-// expand s = append(s, a [, b]* ) to
-// 
-//   const argc = len(args) - 1
-//   if cap(s) - len(s) < argc {
-//        s = growslice(s, argc) 
-//   }
-//   n := len(s)
-//   s = s[:n+argc]
-//   s[n] = a
-//   s[n+1] = b
-// ...
-//
-static int
-oasappend(Node **np, NodeList **init)
 {
        NodeList *l, *a;
-       Node *n, *ns, *nn, *na, *nx, *fn;
+       Node *nsrc, *ns, *nn, *na, *nx, *fn;
        int argc;
 
-       n = *np;
+       walkexprlistsafe(n->list, init);
 
-       // Check that it's an assignment of the form s = append(s, elem), where s is ONAME.
-       if (n->right == N || n->right->op != OAPPEND || n->right->isddd || 
-           n->left == N || n->left->op != ONAME || n->left != n->right->list->n)
-               return 0;
-
-       ns = cheapexpr(n->left, init);
-       walkexprlistsafe(n->right->list, init);
-       argc = count(n->right->list) - 1;
+       nsrc = n->list->n;
+       argc = count(n->list) - 1;
        if (argc < 1) {
-               n->op = OEMPTY;
-               return 1;
+               return nsrc;
        }
 
-       na = nodintconst(argc);         // const argc
+       l = nil;
+
+       ns = nod(OXXX, N, N);             // var s
+       tempname(ns, nsrc->type);
+       l = list(l, nod(OAS, ns, nsrc));  // s = src
 
+       na = nodintconst(argc);         // const argc
        nx = nod(OIF, N, N);            // if cap(s) - len(s) < argc
-       nx->lineno = n->lineno;
        nx->ntest = nod(OLT, nod(OSUB, nod(OCAP, ns, N), nod(OLEN, ns, N)), na);
 
        fn = syslook("growslice", 1);   //   growslice(<type>, old []T, n int64) (ret []T)
@@ -2462,7 +2425,7 @@ oasappend(Node **np, NodeList **init)
                                               typename(ns->type),
                                               ns,
                                               conv(na, types[TINT64]))));
-       l = list1(nx);
+       l = list(l, nx);
 
        nn = nod(OXXX, N, N);                            // var n
        tempname(nn, types[TINT]);
@@ -2472,7 +2435,7 @@ oasappend(Node **np, NodeList **init)
        nx->etype = 1;  // disable bounds check
        l = list(l, nod(OAS, ns, nx));                  // s = s[:n+argc]
 
-       for (a = n->right->list->next;  a != nil; a = a->next) {
+       for (a = n->list->next;  a != nil; a = a->next) {
                nx = nod(OINDEX, ns, nn);               // s[n] ...
                nx->etype = 1;  // disable bounds check
                l = list(l, nod(OAS, nx, a->n));        // s[n] = arg
@@ -2481,8 +2444,7 @@ oasappend(Node **np, NodeList **init)
        }
 
        typechecklist(l, Etop);
-       *np = liststmt(l);
-
-       walkstmt(np);
-       return 1;
+       walkstmtlist(l);
+       *init = concat(*init, l);
+       return ns;
 }

diff --git a/src/pkg/runtime/slice.c b/src/pkg/runtime/slice.c
index 0e7f8e080e8a1a3b9b2b9561acd70b401ba3cc45..9146c177f2c2851ae662bb56d44c1e62674a0ba5 100644 (file)
--- a/src/pkg/runtime/slice.c
+++ b/src/pkg/runtime/slice.c
@@ -48,20 +48,6 @@ makeslice1(SliceType *t, int32 len, int32 cap, Slice *ret)
                ret->array = runtime·mal(size);
 }
 
-// append(type *Type, n int, old []T, ...,) []T
-#pragma textflag 7
-void
-runtime·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)));
-       appendslice1(t, old, sl, ret);
-}
-
 // appendslice(type *Type, x, y, []T) []T
 void
 runtime·appendslice(SliceType *t, Slice x, Slice y, Slice ret)