Bug 674843 - Censor pushed-but-not-active InvokeSessionGuard frames from the debugger's view (r=waldo)

--HG--
extra : rebase_source : 1003735f0bce7b0de41c794702e0840cc6452edf

js/src/jit-test/tests/basic/testBug663789-2.js

@@ -1,11 +1,6 @@
 // |jit-test| debug;mjit
 
-/*
- * NOTE: this evalInFrame is explicitly exposing an optimization artifact that
- * InvokeSessionGuard leaves the callee frame on the stack between invocations.
- * If this ever gets fixed or InvokeSessionGuard gets removed, this test will
- * fail and it can be removed.
- */
-o = { toString:function() { return evalInFrame(1, "arguments; x") } }
+o = { toString:function() { return evalInFrame(1, "x") } }
+var x = 'C';
 var s = "aaaaaaaaaa".replace(/a/g, function() { var x = 'B'; return o });
-assertEq(s, "BBBBBBBBBB");
+assertEq(s, "CCCCCCCCCC");

js/src/jsinterp.cpp

@@ -709,6 +709,9 @@ InvokeSessionGuard::start(JSContext *cx, const Value &calleev, const Value &this
     savedCallee_ = args_.calleev() = calleev;
     savedThis_ = args_.thisv() = thisv;
 
+    /* If anyone (through jsdbgapi) finds this frame, make it safe. */
+    MakeRangeGCSafe(args_.argv(), args_.argc());
+
     do {
         /* Hoist dynamic checks from scripted Invoke. */
         if (!calleev.isObject())

js/src/vm/Stack.cpp

@@ -963,6 +963,12 @@ StackIter::settleOnNewState()
                 continue;
             }
 
+            /* Censor pushed-but-not-active frames from InvokeSessionGuard. */
+            if (containsCall && !calls_->active() && calls_->argv() == fp_->actualArgs()) {
+                popFrame();
+                continue;
+            }
+
             /*
              * As an optimization, there is no CallArgsList element pushed for
              * natives called directly by a script (compiled or interpreted).