cmd/gc: racewalk: fix instrumentation of structs

+ do not instrument go.itab.*

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/6819106

diff --git a/src/cmd/gc/racewalk.c b/src/cmd/gc/racewalk.c
index 93a3f92b0b568cc9c82623121ccb03356da13e77..d0579f9a5ab85f2cd67b32106a84283be0b67cee 100644 (file)
--- a/src/cmd/gc/racewalk.c
+++ b/src/cmd/gc/racewalk.c
@@ -382,6 +382,27 @@ ret:
        *np = n;
 }
 
+static int
+isartificial(Node *n)
+{
+       // compiler-emitted artificial things that we do not want to instrument,
+       // cant' possibly participate in a data race.
+       if(n->op == ONAME && n->sym != S && n->sym->name != nil) {
+               if(strcmp(n->sym->name, "_") == 0)
+                       return 1;
+               // autotmp's are always local
+               if(strncmp(n->sym->name, "autotmp_", sizeof("autotmp_")-1) == 0)
+                       return 1;
+               // statictmp's are read-only
+               if(strncmp(n->sym->name, "statictmp_", sizeof("statictmp_")-1) == 0)
+                       return 1;
+               // go.itab is accessed only by the compiler and runtime (assume safe)
+               if(n->sym->pkg && n->sym->pkg->name && strcmp(n->sym->pkg->name, "go.itab") == 0)
+                       return 1;
+       }
+       return 0;
+}
+
 static int
 callinstr(Node **np, NodeList **init, int wr, int skip)
 {
@@ -390,25 +411,18 @@ callinstr(Node **np, NodeList **init, int wr, int skip)
        int class, res, hascalls;
 
        n = *np;
-       //print("callinstr for %N [ %s ] etype=%d class=%d\n",
-       //        n, opnames[n->op], n->type ? n->type->etype : -1, n->class);
+       //print("callinstr for %+N [ %O ] etype=%d class=%d\n",
+       //        n, n->op, n->type ? n->type->etype : -1, n->class);
 
        if(skip || n->type == T || n->type->etype >= TIDEAL)
                return 0;
        t = n->type;
-       if(n->op == ONAME) {
-               if(n->sym != S) {
-                       if(n->sym->name != nil) {
-                               if(strcmp(n->sym->name, "_") == 0)
-                                       return 0;
-                               if(strncmp(n->sym->name, "autotmp_", sizeof("autotmp_")-1) == 0)
-                                       return 0;
-                               if(strncmp(n->sym->name, "statictmp_", sizeof("statictmp_")-1) == 0)
-                                       return 0;
-                       }
-               }
-       }
+       if(isartificial(n))
+               return 0;
        if(t->etype == TSTRUCT) {
+               // PARAMs w/o PHEAP are not interesting.
+               if(n->class == PPARAM || n->class == PPARAMOUT)
+                       return 0;
                res = 0;
                hascalls = 0;
                foreach(n, hascallspred, &hascalls);
@@ -420,6 +434,7 @@ callinstr(Node **np, NodeList **init, int wr, int skip)
                        if(t1->sym && strcmp(t1->sym->name, "_")) {
                                n = treecopy(n);
                                f = nod(OXDOT, n, newname(t1->sym));
+                               f->type = t1;
                                if(callinstr(&f, init, wr, 0)) {
                                        typecheck(&f, Erv);
                                        res = 1;
@@ -430,6 +445,9 @@ callinstr(Node **np, NodeList **init, int wr, int skip)
        }
 
        b = basenod(n);
+       // it skips e.g. stores to ... parameter array
+       if(isartificial(b))
+               return 0;
        class = b->class;
        // BUG: we _may_ want to instrument PAUTO sometimes
        // e.g. if we've got a local variable/method receiver
@@ -467,7 +485,7 @@ static Node*
 basenod(Node *n)
 {
        for(;;) {
-               if(n->op == ODOT || n->op == OPAREN) {
+               if(n->op == ODOT || n->op == OXDOT || n->op == OCONVNOP || n->op == OCONV || n->op == OPAREN) {
                        n = n->left;
                        continue;
                }