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Bug 761864 - add write barrier on generator close (r=terrence)

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This commit is contained in:
Luke Wagner
2012-06-08 21:14:20 -07:00
parent 90be22291b
commit 0296d574f8
4 changed files with 111 additions and 33 deletions
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43
js/src/jsiter.cpp
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@@ -1331,7 +1331,7 @@ generator_finalize(FreeOp *fop, JSObject *obj)
}
static void
MarkGenerator(JSTracer *trc, JSGenerator *gen)
MarkGeneratorFrame(JSTracer *trc, JSGenerator *gen)
{
MarkValueRange(trc,
HeapValueify(gen->fp->generatorArgsSnapshotBegin()),
@@ -1349,7 +1349,31 @@ GeneratorWriteBarrierPre(JSContext *cx, JSGenerator *gen)
{
JSCompartment *comp = cx->compartment;
if (comp->needsBarrier())
MarkGenerator(comp->barrierTracer(), gen);
MarkGeneratorFrame(comp->barrierTracer(), gen);
}
/*
* Only mark generator frames/slots when the generator is not active on the
* stack or closed. Barriers when copying onto the stack or closing preserve
* gc invariants.
*/
static bool
GeneratorHasMarkableFrame(JSGenerator *gen)
{
return gen->state == JSGEN_NEWBORN || gen->state == JSGEN_OPEN;
}
/*
* When a generator is closed, the GC things reachable from the contained frame
* and slots become unreachable and thus require a write barrier.
*/
static void
SetGeneratorClosed(JSContext *cx, JSGenerator *gen)
{
JS_ASSERT(gen->state != JSGEN_CLOSED);
if (GeneratorHasMarkableFrame(gen))
GeneratorWriteBarrierPre(cx, gen);
gen->state = JSGEN_CLOSED;
}
static void
@@ -1359,8 +1383,8 @@ generator_trace(JSTracer *trc, JSObject *obj)
if (!gen)
return;
if (gen->state == JSGEN_NEWBORN || gen->state == JSGEN_OPEN)
MarkGenerator(trc, gen);
if (GeneratorHasMarkableFrame(gen))
MarkGeneratorFrame(trc, gen);
}
Class js::GeneratorClass = {
@@ -1444,12 +1468,15 @@ js_NewGenerator(JSContext *cx)
/* Copy from the stack to the generator's floating frame. */
gen->regs.rebaseFromTo(stackRegs, *genfp);
genfp->copyFrameAndValues<HeapValue, Value, StackFrame::DoPostBarrier>(
cx, genfp, genvp, stackfp, stackvp, stackRegs.sp);
cx, genvp, stackfp, stackvp, stackRegs.sp);
obj->setPrivate(gen);
return obj;
}
static void
SetGeneratorClosed(JSContext *cx, JSGenerator *gen);
typedef enum JSGeneratorOp {
JSGENOP_NEXT,
JSGENOP_SEND,
@@ -1513,7 +1540,7 @@ SendToGenerator(JSContext *cx, JSGeneratorOp op, JSObject *obj,
{
GeneratorFrameGuard gfg;
if (!cx->stack.pushGeneratorFrame(cx, gen, &gfg)) {
gen->state = JSGEN_CLOSED;
SetGeneratorClosed(cx, gen);
return JS_FALSE;
}
@@ -1543,7 +1570,7 @@ SendToGenerator(JSContext *cx, JSGeneratorOp op, JSObject *obj,
}
gen->fp->clearReturnValue();
gen->state = JSGEN_CLOSED;
SetGeneratorClosed(cx, gen);
if (ok) {
/* Returned, explicitly or by falling off the end. */
if (op == JSGENOP_CLOSE)
@@ -1611,7 +1638,7 @@ generator_op(JSContext *cx, Native native, JSGeneratorOp op, Value *vp, unsigned
default:
JS_ASSERT(op == JSGENOP_CLOSE);
gen->state = JSGEN_CLOSED;
SetGeneratorClosed(cx, gen);
args.rval().setUndefined();
return true;
}