[infer][clang] fix unitialized value false positive for values not initialized in the throw branch

Summary: The checker should not report unitinialzed values on the throw branch.

Reviewed By: ddino

Differential Revision: D6267019

fbshipit-source-id: 05768f1

infer/src/checkers/uninit.ml

@@ -103,6 +103,9 @@ module TransferFunctions (CFG : ProcCfg.S) = struct
     | Assign (((lhs_var, _), _), _, _) ->
         let uninit_vars = D.remove lhs_var astate.uninit_vars in
         {astate with uninit_vars}
+    | Call (_, Direct callee_pname, _, _, _)
+      when Typ.Procname.equal callee_pname BuiltinDecl.objc_cpp_throw ->
+        {astate with uninit_vars= D.empty}
     | Call (_, call, actuals, _, loc) ->
         (* in case of intraprocedural only analysis we assume that parameters passed by reference
            to a function will be initialized inside that function *)

infer/tests/codetoanalyze/cpp/uninit/issues.exp

@@ -1,6 +1,8 @@
+codetoanalyze/cpp/uninit/uninit.cpp, FP_no_warning_noreturn_callee_ok, 7, UNINITIALIZED_VALUE, []
 codetoanalyze/cpp/uninit/uninit.cpp, bad1, 2, UNINITIALIZED_VALUE, []
 codetoanalyze/cpp/uninit/uninit.cpp, bad2, 2, UNINITIALIZED_VALUE, []
 codetoanalyze/cpp/uninit/uninit.cpp, branch1_FP, 11, UNINITIALIZED_VALUE, []
 codetoanalyze/cpp/uninit/uninit.cpp, loop1_FP, 10, UNINITIALIZED_VALUE, []
 codetoanalyze/cpp/uninit/uninit.cpp, no_init_return_bad, 2, UNINITIALIZED_VALUE, []
 codetoanalyze/cpp/uninit/uninit.cpp, ret_undef, 2, UNINITIALIZED_VALUE, []
+codetoanalyze/cpp/uninit/uninit.cpp, warning_when_throw_in_other_branch_bad, 9, UNINITIALIZED_VALUE, []

infer/tests/codetoanalyze/cpp/uninit/uninit.cpp

@@ -224,3 +224,37 @@ int capture_by_ref_init_ok() {
   [&x]() { x = 1; }();
   return x;
 }
+
+int no_warning_on_throw_ok(bool t) {
+  int x;
+  if (t) {
+    x = 2;
+  } else {
+    throw;
+  }
+  return x;
+}
+
+int warning_when_throw_in_other_branch_bad(int t) {
+  int x;
+  if (t > 0) {
+    x = 2;
+  } else if (t < 0) {
+    // reports because x is not initialized in this branch
+  } else {
+    throw;
+  }
+  return x;
+}
+
+[[noreturn]] void noreturn_function() {}
+
+int FP_no_warning_noreturn_callee_ok(bool t) {
+  int x;
+  if (t) {
+    x = 2;
+  } else {
+    noreturn_function();
+  }
+  return x;
+}