[clang] [analyzer] Model overflow builtins (PR #102602)

[Donát Nagy via cfe-commits]

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@@ -50,6 +101,44 @@ class BuiltinFunctionChecker : public Checker<eval::Call> {
 
 } // namespace
 
+void BuiltinFunctionChecker::HandleOverflowBuiltin(const CallEvent &Call,
+                                                   CheckerContext &C,
+                                                   BinaryOperator::Opcode Op,
+                                                   QualType ResultType) const {
+  // All __builtin_*_overflow functions take 3 argumets.
+  assert(Call.getNumArgs() == 3);
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NagyDonat wrote:

> I've tried to catch this assert locally by calling __builtin_*_overflow with 2 arguments, but clang just rejects it.

Oh, I see. Perhaps add a comment saying that "Calling a builtin with an incorrect argument count produces compiler error (...)", because e.g. I didn't know that this is the case.

https://github.com/llvm/llvm-project/pull/102602