Bug 877473 - Expose tools to help fuzz generational GC; r=billm

--HG--
extra : rebase_source : 46dd430429e31ab380b61ef8b0019fc20a411961

js/src/builtin/TestingFunctions.cpp

@@ -224,6 +224,20 @@ GC(JSContext *cx, unsigned argc, jsval *vp)
     return true;
 }
 
+static JSBool
+MinorGC(JSContext *cx, unsigned argc, jsval *vp)
+{
+#ifdef JSGC_GENERATIONAL
+    CallArgs args = CallArgsFromVp(argc, vp);
+
+    if (args.get(0) == BooleanValue(true))
+        cx->runtime()->gcStoreBuffer.setOverflowed();
+
+    MinorGC(cx->runtime(), gcreason::API);
+#endif
+    return true;
+}
+
 static const struct ParamPair {
     const char      *name;
     JSGCParamKey    param;
@@ -993,6 +1007,11 @@ static JSFunctionSpecWithHelp TestingFunctions[] = {
 "  If 'compartment' is given, GC any compartments that were scheduled for\n"
 "  GC via schedulegc."),
 
+    JS_FN_HELP("minorgc", ::MinorGC, 0, 0,
+"minorgc([overflow])",
+"  Run a minor collector on the Nursery. When overflow is true, marks the\n"
+"  store buffer as overflowed before collecting."),
+
     JS_FN_HELP("gcparam", GCParameter, 2, 0,
 "gcparam(name [, value])",
 "  Wrapper for JS_[GS]etGCParameter. The name is either maxBytes,\n"

js/src/gc/StoreBuffer.h

@@ -433,10 +433,6 @@ class StoreBuffer
                                     RelocValueBufferSize + RelocCellBufferSize +
                                     GenericBufferSize;
 
-    /* For use by our owned buffers. */
-    void setAboutToOverflow();
-    void setOverflowed();
-
   public:
     explicit StoreBuffer(JSRuntime *rt)
       : bufferVal(this), bufferCell(this), bufferSlot(this), bufferWholeObject(this),
@@ -496,6 +492,10 @@ class StoreBuffer
     bool coalesceForVerification();
     void releaseVerificationData();
     bool containsEdgeAt(void *loc) const;
+
+    /* For use by our owned buffers and for testing. */
+    void setAboutToOverflow();
+    void setOverflowed();
 };
 
 } /* namespace gc */