[PATCH] D124807: [clang][dataflow] Avoid assert for invalid cast to BoolValue

[Stanislav Gatev via Phabricator via cfe-commits]

sgatev added inline comments.


================
Comment at: clang/lib/Analysis/FlowSensitive/TypeErasedDataflowAnalysis.cpp:78
+/// and integers in the framework.
+static const Expr *ignoreParenImpCastsExceptToBool(const Expr *E) {
+  const Expr *LastE = nullptr;
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xazax.hun wrote:
> li.zhe.hua wrote:
> > sgatev wrote:
> > > I don't recall why we need to ignore implicit casts here. Can't we ignore parens and rely on the built-in transfer function, possibly adding handling of some missing casts there? https://github.com/llvm/llvm-project/blob/main/clang/lib/Analysis/FlowSensitive/Transfer.cpp#L192
> > If we only ignore parens, a test in the optional checker tests begins to fail, specifically `UncheckedOptionalAccessTest.ValueOrComparison`. The missing "cast" is an `ExprWithCleanups`. I didn't know how to deal with that, so this patch just working around the assert.
> In general, I prefer to handle as much as possible with transfer functions and skip as little as possible in the AST. We might skip `ExprWithCleanups` nodes today, but we will need them tomorrow to properly model where certain destructors are being invoked. 
We already have `skipExprWithCleanups` [1]. I wonder if it makes sense to replace that with a simple transfer function like the one for the `CK_NoOp` implicit cast. Would that solve the problem and remove the need for `ignoreParenImpCastsExceptToBool`? In the future we might replace that transfer function with a proper one, as Gábor suggested.

[1] https://github.com/llvm/llvm-project/blob/main/clang/lib/Analysis/FlowSensitive/Transfer.cpp#L36


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https://reviews.llvm.org/D124807