Phase 3: Py_CHECKWRITE -> write barrier todo list

[xFrednet]

An extract of all Py_CHECKWRITE() calls which need to be adjusted for the write barrier. (From the phase3 branch)

Objects/abstract.c (owner @TobiasWrigstad)

• Line 224: if(!Py_CHECKWRITE(o)){
• Line 236: if(!Py_CHECKWRITE(o)){
• Line 268: if(!Py_CHECKWRITE(o)){
• Line 280: if(!Py_CHECKWRITE(o)){
• Line 395: if(!Py_CHECKWRITE(obj)){
• Line 429: if((flags & PyBUF_WRITABLE) && !Py_CHECKWRITE(obj)){
• Line 1224: if(!Py_CHECKWRITE(v)){
• Line 1270: if(!Py_CHECKWRITE(v)){
• Line 1861: if(!Py_CHECKWRITE(s)){
• Line 1894: if (!Py_CHECKWRITE(o)){
• Line 1985: if (!Py_CHECKWRITE(s)){
• Line 2023: if(!Py_CHECKWRITE(s)){
• Line 2061: if (!Py_CHECKWRITE(s)){
• Line 2089: if(!Py_CHECKWRITE(s)){

Python/generated_cases.c.h

• Line 1923: if (!Py_CHECKWRITE(cell)){
• Line 1999: if(!Py_CHECKWRITE(cell)){
• Line 2723: if (!Py_CHECKWRITE(owner))
• Line 2759: if (!Py_CHECKWRITE(owner))
• Line 2818: if (!Py_CHECKWRITE(owner))

Objects/setobject.c

• Line 637: if(!Py_CHECKWRITE(so)){
• Line 936: if(!Py_CHECKWRITE(so)){
• Line 1118: if(!Py_CHECKWRITE(so)){
• Line 1845: if(!Py_CHECKWRITE(so)){
• Line 1898: if(!Py_CHECKWRITE(so)){
• Line 1934: if(!Py_CHECKWRITE(so)){
• Line 2319: if(!Py_CHECKWRITE(set)){
• Line 2345: if(!Py_CHECKWRITE(set)){
• Line 2362: if(!Py_CHECKWRITE(anyset)){

Objects/listobject.c

• Line 270: if(!Py_CHECKWRITE(op)){
• Line 323: if (!Py_CHECKWRITE(op)){
• Line 348: if (!Py_CHECKWRITE(op)){
• Line 754: if(!Py_CHECKWRITE(a)){
• Line 821: if (!Py_CHECKWRITE(self)){
• Line 840: if (!Py_CHECKWRITE(self)){
• Line 874: if (!Py_CHECKWRITE(self)){
• Line 904: if(!Py_CHECKWRITE(self)){
• Line 1058: if(!Py_CHECKWRITE(self)){
• Line 2311: if (!Py_CHECKWRITE(self)){
• Line 2588: if (!Py_CHECKWRITE(self)){
• Line 2607: if (!Py_CHECKWRITE(v)){
• Line 2740: if (!Py_CHECKWRITE(self)){

Objects/dictobject.c (@mjp41 owner)

• Line 1241: if (!Py_CHECKWRITE(mp)){
• Line 1359: if (!Py_CHECKWRITE(mp)){
• Line 2088: if(!Py_CHECKWRITE(op)){
• Line 2156: if(!Py_CHECKWRITE(op)){
• Line 2799: if(!Py_CHECKWRITE(self)){
• Line 3399: if(!Py_CHECKWRITE(d)){
• Line 3510: if(!Py_CHECKWRITE(mp)){
• Line 3535: if(!Py_CHECKWRITE(self)){
• Line 3560: if(!Py_CHECKWRITE(self)){
• Line 5553: if(!Py_CHECKWRITE(obj)){

Objects/object.c (@TobiasWrigstad owner -- see #26)

• Line 1176: if(Py_CHECKWRITE(v)){
• Line 1193: if(Py_CHECKWRITE(v)){
• Line 1639: if(!Py_CHECKWRITE(obj)){

Objects/tupleobject.c (@TobiasWrigstad owner -- see #46)

• Line 121: if (!Py_CHECKWRITE(op)){

Objects/cellobject.c (@xFrednet owner)

• Line 71: (!Py_CHECKWRITE(op)){
• Line 131: if(!Py_CHECKWRITE(op)){
• Line 154: if(!Py_CHECKWRITE(op)){

Python/bytecodes.c (@xFrednet owner)

• Line 1414: if (!Py_CHECKWRITE(cell)){
• Line 1474: if(!Py_CHECKWRITE(cell)){
• Line 1969: if (!Py_CHECKWRITE(owner))
• Line 1996: if (!Py_CHECKWRITE(owner))
• Line 2046: if (!Py_CHECKWRITE(owner))

Include/cpython/listobject.h

• Line 43: if (_Py_IsImmutable(op)){ // _Py_CHECKWRITE(op) is not available

---

cc: @mjp41 @TobiasWrigstad

[mjp41]

Based on looking through I think we might want

PY_REGIONCHECKINSERT(src, newtgt);
PY_REGIONCHECKREMOVE(src, oldtgt);
PY_REGIONCHECKREPLACE(src, oldtgt, newtgt);
PY_REGIONCHECKREPLACEUNKNOWN(src, newtgt); // Used when we lose precision

There are places I have found that only add or remove, e.g. clearing the dictionary only performs remove.

[xFrednet]

Tiny nit: I think by convention the y in Py should be lower case.

I assume with // Used when we lose precision you mean we mark regions as dirty? So we lose our guarantees until we reestablish them?

[mjp41]

Yeah, I had changed to Py locally when I started typing, but good catch.

Yes, lose precision, is the region is dirty, and might not satisfy the invariant.

I also after trying to use these macros for a few minutes think they need to change. I think we need variandic macros:

With the macros above, if we want to support backing out a failure, then we would need to write something like:

    if (!Py_REGIONCHECKINSERT(mp, key)) {
        goto Fail;
    }

    if (!Py_REGIONCHECKINSERT(mp, value)) {
        Py_REGIONCHECKREMOVE(mp, key);
        goto Fail;
    }

If we had a variadic insert, we could write

    if (!Py_REGIONCHECKINSERT(mp, key, value)) {
        goto Fail;
    }

So, I am trying my changes with this kind of alternative now, which would internally do the back tracking (or at least could be made to).

[xFrednet]

Maybe relevant for the fail:

I'm currently creating a draft/dummy RegionException. I think later we want to distinguish between different types of Pyrona errors. Including an indicator if the system is in a valid state after the exception.

These checks should usually leave the system in a valid state, but cleaning might fail and have invalid references remain afterwards