[clang] [clang] [Static analyzer]: add initial support for builtin overflow (PR #102602)

[Balazs Benics 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
+  // unreachable.
+
+  // Handle non-overflow case.
+  {
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steakhal wrote:

Could you drop these curlies?
When I see something like this, I start looking for dtors that are bound by this scope - but there is nothing going on here.

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