sgraenitz added a comment.
Thanks for your feedback @rnk! I hope some of the ObjCARCOpts authors will
share their opinions as well.
================
Comment at: llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp:767
+ const ColorVector &CV = BlockColors.find(BB)->second;
+ assert(CV.size() == 1 && "non-unique color for block!");
+ BasicBlock *EHPadBB = CV.front();
----------------
rnk wrote:
> I don't think the verifier changes you made guarantee this. I would consider
> strengthening this to `report_fatal_error`, since valid IR transforms can
> probably reach this code.
Right, I guess the Verifier change is correct and this should change to work
for multi-color BBs?
```
assert(CV.size() > 0 && "Uncolored block");
for (BasicBlock *EHPadBB : CV)
if (auto *EHPad =
dyn_cast<FuncletPadInst>(ColorFirstBB->getFirstNonPHI())) {
OpBundles.emplace_back("funclet", EHPad);
break;
}
```
There is no test that covers this case, but it appears that the unique color
invariant only holds **after** WinEHPrepare. [The assertion
here](https://github.com/llvm/llvm-project/blob/release/15.x/llvm/lib/CodeGen/WinEHPrepare.cpp#L185)
seems to imply it:
```
assert(BBColors.size() == 1 && "multi-color BB not removed by preparation");
```
Since it would be equivalent to the Verifier check, I'd stick with the
assertion and not report a fatal error.
================
Comment at: llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp:2040-2041
+ DenseMap<BasicBlock *, ColorVector> BlockColors;
+ if (F.hasPersonalityFn() &&
+ isScopedEHPersonality(classifyEHPersonality(F.getPersonalityFn())))
+ BlockColors = colorEHFunclets(F);
----------------
rnk wrote:
> I think this code snippet probably deserves a Function helper,
> `F->hasScopedEHPersonality()`. Another part of me thinks we should cache the
> personality enum similar to the way we cache intrinsic ids, but I wouldn't
> want to increase Function memory usage, so that seems premature. "No action
> required", I guess.
It doesn't really fit the the scope of this patch but I am happy to add the
helper function in a follow-up (for now without personality enum caching).
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D137944/new/
https://reviews.llvm.org/D137944
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