cmd/gc: track parameter flow, step 0: synthesize name nodes for anonymous PPARAMOUTs...

further work on parameter flow tracking for escape analysis depends on this.

R=rsc
CC=golang-dev
https://golang.org/cl/6600044

diff --git a/src/cmd/gc/closure.c b/src/cmd/gc/closure.c
index cc44d7f6b0f861a532b97f5a03df53d920d7647f..2043ab0ed73552958458b7066e0af950b81668b3 100644 (file)
--- a/src/cmd/gc/closure.c
+++ b/src/cmd/gc/closure.c
@@ -13,7 +13,7 @@
 void
 closurehdr(Node *ntype)
 {
-       Node *n, *name, *a;
+       Node *n, *name, *a, *orig;
        NodeList *l;
 
        n = nod(OCLOSURE, N, N);
@@ -43,8 +43,11 @@ closurehdr(Node *ntype)
        }
        for(l=n->rlist; l; l=l->next) {
                name = l->n->left;
-               if(name)
+               if(name) {
+                       orig = name->orig;  // preserve the meaning of orig == N (anonymous PPARAMOUT)
                        name = newname(name->sym);
+                       name->orig = orig;
+               }
                ntype->rlist = list(ntype->rlist, nod(ODCLFIELD, name, l->n->right));
        }
 }

diff --git a/src/cmd/gc/dcl.c b/src/cmd/gc/dcl.c
index d090380d7eeadd62d25c2f6999cd15d4039c3001..2f4f5477617b2f139c6b6e1c409395c0dc536239 100644 (file)
--- a/src/cmd/gc/dcl.c
+++ b/src/cmd/gc/dcl.c
@@ -596,25 +596,38 @@ funcargs(Node *nt)
        }
 
        // declare the out arguments.
-       gen = 0;
+       gen = count(nt->list);
+       int i = 0;
        for(l=nt->rlist; l; l=l->next) {
                n = l->n;
+
                if(n->op != ODCLFIELD)
                        fatal("funcargs out %O", n->op);
-               if(n->left != N) {
-                       n->left->op = ONAME;
-                       n->left->ntype = n->right;
-                       if(isblank(n->left)) {
-                               // Give it a name so we can assign to it during return.
-                               // preserve the original in ->orig
-                               nn = nod(OXXX, N, N);
-                               *nn = *n->left;
-                               n->left = nn;
-                               snprint(namebuf, sizeof(namebuf), ".anon%d", gen++);
-                               n->left->sym = lookup(namebuf);
-                       }
-                       declare(n->left, PPARAMOUT);
+
+               if(n->left == N) {
+                       // give it a name so escape analysis has nodes to work with
+                       snprint(namebuf, sizeof(namebuf), ".anon%d", gen++);
+                       n->left = newname(lookup(namebuf));
+                       n->left->orig = N;  // signal that the original was absent
+
+               } 
+
+               n->left->op = ONAME;
+
+               if(isblank(n->left)) {
+                       // Give it a name so we can assign to it during return.
+                       // preserve the original in ->orig
+                       nn = nod(OXXX, N, N);
+                       *nn = *n->left;
+                       n->left = nn;
+                       
+                       snprint(namebuf, sizeof(namebuf), ".anon%d", gen++);
+                       n->left->sym = lookup(namebuf);
                }
+
+               n->left->ntype = n->right;
+               declare(n->left, PPARAMOUT);
+               n->left->vargen = i++;
        }
 }
 
@@ -769,7 +782,7 @@ structfield(Node *n)
                break;
        }
 
-       if(n->left && n->left->op == ONAME) {
+       if(n->left && n->left->op == ONAME && n->left->orig != N) {
                f->nname = n->left;
                f->embedded = n->embedded;
                f->sym = f->nname->sym;
@@ -1145,7 +1158,7 @@ functype(Node *this, NodeList *in, NodeList *out)
                t->thistuple = 1;
        t->outtuple = count(out);
        t->intuple = count(in);
-       t->outnamed = t->outtuple > 0 && out->n->left != N;
+       t->outnamed = t->outtuple > 0 && out->n->left != N && out->n->left->orig != N;
 
        return t;
 }

diff --git a/src/cmd/gc/fmt.c b/src/cmd/gc/fmt.c
index 6945e9c8e3d976bcadbe967a209562b28d75bf99..33a2176b93dc3e10a61391a4e4d456705559b951 100644 (file)
--- a/src/cmd/gc/fmt.c
+++ b/src/cmd/gc/fmt.c
@@ -518,6 +518,8 @@ symfmt(Fmt *fp, Sym *s)
                                return fmtprint(fp, "%s.%s", s->pkg->name, s->name);    // dcommontype, typehash
                        return fmtprint(fp, "%s.%s", s->pkg->prefix, s->name);  // (methodsym), typesym, weaksym
                case FExp:
+                       if(s->name && s->name[0] == '.')
+                               fatal("exporting synthetic symbol %s", s->name);
                        if(s->pkg != builtinpkg)
                                return fmtprint(fp, "@\"%Z\".%s", s->pkg->path, s->name);
                }
@@ -713,9 +715,13 @@ typefmt(Fmt *fp, Type *t)
        case TFIELD:
                if(!(fp->flags&FmtShort)) {
                        s = t->sym;
+
                        // Take the name from the original, lest we substituted it with .anon%d
-                       if (t->nname && (fmtmode == FErr || fmtmode == FExp))
-                               s = t->nname->orig->sym;
+                       if ((fmtmode == FErr || fmtmode == FExp) && t->nname != N)
+                               if(t->nname->orig != N)
+                                       s = t->nname->orig->sym;
+                               else 
+                                       s = S;
                        
                        if(s != S && !t->embedded) {
                                if(fp->flags&FmtLong)