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

[Pavel Skripkin 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);
+
+  ProgramStateRef State = C.getState();
+  SValBuilder &SVB = C.getSValBuilder();
+  const Expr *CE = Call.getOriginExpr();
+
+  SVal Arg1 = Call.getArgSVal(0);
+  SVal Arg2 = Call.getArgSVal(1);
+
+  SVal RetVal = SVB.evalBinOp(State, Op, Arg1, Arg2, ResultType);
+
+  // TODO: Handle overflows with values that known to overflow. Like INT_MAX + 1
+  // should not produce state for non-overflow case and threat it as
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pskrgag wrote:

> Assuming that a and b are signed integers

Oh, sorry, I forgot to mention that `a` and `b` are unsigned. I've showed this in `test_uadd_overflow_contraints` test in this pr

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