[clang] [clang][dataflow] Make cap on block visits configurable by caller. (PR #77481)

[Yitzhak Mandelbaum via cfe-commits]

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@@ -138,13 +138,20 @@ struct TypeErasedDataflowAnalysisState {
 /// dataflow analysis cannot be performed successfully. Otherwise, calls
 /// `PostVisitCFG` on each CFG element with the final analysis results at that
 /// program point.
+///
+/// `MaxBlockVisits` caps the number of block visits during analysis. It doesn't
+/// distinguish between repeat visits to the same block and visits to distinct
+/// blocks. This parameter is a backstop to prevent infintite loops, in the case
+/// of bugs in the lattice and/or transfer functions that prevent the analysis
+/// from converging.
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ymand wrote:

See the FIXME -- I'm planning to followup (quickly) with a patch that removes that restriction, once callers have a chance to set their own limits. So, i don't think its worth documenting a feature that we're about to remove.

https://github.com/llvm/llvm-project/pull/77481