cmd/gc: fix addresses escaping through closures called in-place.
Fixes #3545.
R=rsc
CC=golang-dev
https://golang.org/cl/6061043
diff --git a/src/cmd/gc/esc.c b/src/cmd/gc/esc.c
index 2614b5f..8a265ce 100644
--- a/src/cmd/gc/esc.c
+++ b/src/cmd/gc/esc.c
@@ -131,7 +131,12 @@
}
// walk will take the address of cvar->closure later and assign it to cvar.
- // handle that here by linking a fake oaddr node directly to the closure.
+ // linking a fake oaddr node directly to the closure handles the case
+ // of the closure itself leaking. Following the flow of the value to th
+ // paramref is done in escflow, because if we did that here, it would look
+ // like the original is assigned out of its loop depth, whereas it's just
+ // assigned to something in an inner function. A paramref itself is never
+ // moved to the heap, only its original.
for(ll=curfn->cvars; ll; ll=ll->next) {
if(ll->n->op == OXXX) // see dcl.c:398
continue;
@@ -221,16 +226,19 @@
if(n->op == OFOR || n->op == ORANGE)
loopdepth++;
- esc(n->left);
- esc(n->right);
- esc(n->ntest);
- esc(n->nincr);
- esclist(n->ninit);
- esclist(n->nbody);
- esclist(n->nelse);
- esclist(n->list);
- esclist(n->rlist);
-
+ if(n->op == OCLOSURE) {
+ escfunc(n);
+ } else {
+ esc(n->left);
+ esc(n->right);
+ esc(n->ntest);
+ esc(n->nincr);
+ esclist(n->ninit);
+ esclist(n->nbody);
+ esclist(n->nelse);
+ esclist(n->list);
+ esclist(n->rlist);
+ }
if(n->op == OFOR || n->op == ORANGE)
loopdepth--;
@@ -379,8 +387,8 @@
}
break;
- case OADDR:
case OCLOSURE:
+ case OADDR:
case OMAKECHAN:
case OMAKEMAP:
case OMAKESLICE:
@@ -407,8 +415,8 @@
return;
if(debug['m'] > 1)
- print("%L:[%d] %S escassign: %hN = %hN\n", lineno, loopdepth,
- (curfn && curfn->nname) ? curfn->nname->sym : S, dst, src);
+ print("%L:[%d] %S escassign: %hN(%hJ) = %hN(%hJ)\n", lineno, loopdepth,
+ (curfn && curfn->nname) ? curfn->nname->sym : S, dst, dst, src, src);
setlineno(dst);
@@ -467,7 +475,11 @@
case OARRAYLIT:
case OMAPLIT:
case OSTRUCTLIT:
- // loopdepth was set in the defining statement or function header
+ case OMAKECHAN:
+ case OMAKEMAP:
+ case OMAKESLICE:
+ case ONEW:
+ case OCLOSURE:
escflows(dst, src);
break;
@@ -500,18 +512,6 @@
escassign(dst, src->left);
break;
- case OMAKECHAN:
- case OMAKEMAP:
- case OMAKESLICE:
- case ONEW:
- escflows(dst, src);
- break;
-
- case OCLOSURE:
- escflows(dst, src);
- escfunc(src);
- break;
-
case OADD:
case OSUB:
case OOR:
@@ -543,7 +543,7 @@
// This is a bit messier than fortunate, pulled out of escassign's big
// switch for clarity. We either have the paramnodes, which may be
// connected to other things throug flows or we have the parameter type
-// nodes, which may be marked 'n(ofloworescape)'. Navigating the ast is slightly
+// nodes, which may be marked "noescape". Navigating the ast is slightly
// different for methods vs plain functions and for imported vs
// this-package
static void
@@ -711,8 +711,8 @@
src->walkgen = walkgen;
if(debug['m']>1)
- print("escwalk: level:%d depth:%d %.*s %hN scope:%S[%d]\n",
- level, pdepth, pdepth, "\t\t\t\t\t\t\t\t\t\t", src,
+ print("escwalk: level:%d depth:%d %.*s %hN(%hJ) scope:%S[%d]\n",
+ level, pdepth, pdepth, "\t\t\t\t\t\t\t\t\t\t", src, src,
(src->curfn && src->curfn->nname) ? src->curfn->nname->sym : S, src->escloopdepth);
pdepth++;
@@ -726,6 +726,16 @@
if(debug['m'])
warnl(src->lineno, "leaking param: %hN", src);
}
+ // handle the missing flow ref <- orig
+ // a paramref is automagically dereferenced, and taking its
+ // address produces the address of the original, so all we have to do here
+ // is keep track of the value flow, so level is unchanged.
+ // alternatively, we could have substituted PPARAMREFs with their ->closure in esc/escassign/flow,
+ if(src->class == PPARAMREF) {
+ if(leaks && debug['m'])
+ warnl(src->lineno, "leaking closure reference %hN", src);
+ escwalk(level, dst, src->closure);
+ }
break;
case OPTRLIT:
diff --git a/test/escape2.go b/test/escape2.go
index 624ea80..0bf02c5 100644
--- a/test/escape2.go
+++ b/test/escape2.go
@@ -1051,7 +1051,7 @@
goto L1
L1:
- i = new(int) // ERROR "does not escape"
+ i = new(int) // ERROR "new.int. does not escape"
_ = i
}
@@ -1060,8 +1060,141 @@
var i *int
L1:
- i = new(int) // ERROR "escapes"
+ i = new(int) // ERROR "new.int. escapes to heap"
goto L1
_ = i
}
+
+func foo124(x **int) { // ERROR "x does not escape"
+ var i int // ERROR "moved to heap: i"
+ p := &i // ERROR "&i escapes"
+ func() { // ERROR "func literal does not escape"
+ *x = p // ERROR "leaking closure reference p"
+ }()
+}
+
+func foo125(ch chan *int) { // ERROR "does not escape"
+ var i int // ERROR "moved to heap"
+ p := &i // ERROR "&i escapes to heap"
+ func() { // ERROR "func literal does not escape"
+ ch <- p // ERROR "leaking closure reference p"
+ }()
+}
+
+func foo126() {
+ var px *int // loopdepth 0
+ for {
+ // loopdepth 1
+ var i int // ERROR "moved to heap"
+ func() { // ERROR "func literal does not escape"
+ px = &i // ERROR "&i escapes"
+ }()
+ }
+}
+
+var px *int
+
+func foo127() {
+ var i int // ERROR "moved to heap: i"
+ p := &i // ERROR "&i escapes to heap"
+ q := p
+ px = q
+}
+
+func foo128() {
+ var i int
+ p := &i // ERROR "&i does not escape"
+ q := p
+ _ = q
+}
+
+func foo129() {
+ var i int // ERROR "moved to heap: i"
+ p := &i // ERROR "&i escapes to heap"
+ func() { // ERROR "func literal does not escape"
+ q := p // ERROR "leaking closure reference p"
+ func() { // ERROR "func literal does not escape"
+ r := q // ERROR "leaking closure reference q"
+ px = r
+ }()
+ }()
+}
+
+func foo130() {
+ for {
+ var i int // ERROR "moved to heap"
+ func() { // ERROR "func literal does not escape"
+ px = &i // ERROR "&i escapes" "leaking closure reference i"
+ }()
+ }
+}
+
+func foo131() {
+ var i int // ERROR "moved to heap"
+ func() { // ERROR "func literal does not escape"
+ px = &i // ERROR "&i escapes" "leaking closure reference i"
+ }()
+}
+
+func foo132() {
+ var i int // ERROR "moved to heap"
+ go func() { // ERROR "func literal escapes to heap"
+ px = &i // ERROR "&i escapes" "leaking closure reference i"
+ }()
+}
+
+func foo133() {
+ var i int // ERROR "moved to heap"
+ defer func() { // ERROR "func literal does not escape"
+ px = &i // ERROR "&i escapes" "leaking closure reference i"
+ }()
+}
+
+func foo134() {
+ var i int
+ p := &i // ERROR "&i does not escape"
+ func() { // ERROR "func literal does not escape"
+ q := p
+ func() { // ERROR "func literal does not escape"
+ r := q
+ _ = r
+ }()
+ }()
+}
+
+func foo135() {
+ var i int // ERROR "moved to heap: i"
+ p := &i // ERROR "&i escapes to heap" "moved to heap: p"
+ go func() { // ERROR "func literal escapes to heap"
+ q := p // ERROR "&p escapes to heap"
+ func() { // ERROR "func literal does not escape"
+ r := q
+ _ = r
+ }()
+ }()
+}
+
+func foo136() {
+ var i int // ERROR "moved to heap: i"
+ p := &i // ERROR "&i escapes to heap" "moved to heap: p"
+ go func() { // ERROR "func literal escapes to heap"
+ q := p // ERROR "&p escapes to heap" "leaking closure reference p"
+ func() { // ERROR "func literal does not escape"
+ r := q // ERROR "leaking closure reference q"
+ px = r
+ }()
+ }()
+}
+
+func foo137() {
+ var i int // ERROR "moved to heap: i"
+ p := &i // ERROR "&i escapes to heap"
+ func() { // ERROR "func literal does not escape"
+ q := p // ERROR "leaking closure reference p" "moved to heap: q"
+ go func() { // ERROR "func literal escapes to heap"
+ r := q // ERROR "&q escapes to heap"
+ _ = r
+ }()
+ }()
+}
