From ba422a8ad8afb3852d25fe859f7c820458915e1e Mon Sep 17 00:00:00 2001
From: Dino Distefano <ddino@fb.com>
Date: Mon, 20 Nov 2017 05:51:18 -0800
Subject: [PATCH] Remove FPs for struct in ObjC

Reviewed By: jvillard

Differential Revision: D6368109

fbshipit-source-id: 9794427
---
 infer/src/checkers/uninit.ml                  | 13 ++++++--
 .../tests/codetoanalyze/objc/uninit/uninit.m  | 33 +++++++++++++++++++
 2 files changed, 43 insertions(+), 3 deletions(-)
 create mode 100644 infer/tests/codetoanalyze/objc/uninit/uninit.m

diff --git a/infer/src/checkers/uninit.ml b/infer/src/checkers/uninit.ml
index 3aeb08dc9..f85dad73a 100644
--- a/infer/src/checkers/uninit.ml
+++ b/infer/src/checkers/uninit.ml
@@ -86,7 +86,8 @@ module TransferFunctions (CFG : ProcCfg.S) = struct
 
   let remove_fields tenv base uninit_vars =
     match base with
-    | _, {Typ.desc= Tptr ({Typ.desc= Tstruct name_struct}, _)} -> (
+    | _, {Typ.desc= Tptr ({Typ.desc= Tstruct name_struct}, _)} | _, {Typ.desc= Tstruct name_struct}
+          -> (
       match Tenv.lookup tenv name_struct with
       | Some {fields} ->
           List.fold
@@ -106,10 +107,16 @@ module TransferFunctions (CFG : ProcCfg.S) = struct
       (instr: HilInstr.t) =
     match instr with
     | Assign
-        ( (((_, lhs_typ), _) as lhs_ap)
+        ( (((lhs_var, lhs_typ), apl) as lhs_ap)
         , HilExp.AccessPath (((rhs_var, rhs_typ) as rhs_base), al)
         , loc ) ->
-        let uninit_vars = D.remove lhs_ap astate.uninit_vars in
+        let uninit_vars' = D.remove lhs_ap astate.uninit_vars in
+        let uninit_vars =
+          if Int.equal (List.length apl) 0 then
+            (* if we assign to the root of a struct then we need to remove all the fields *)
+            remove_fields tenv (lhs_var, lhs_typ) uninit_vars'
+          else uninit_vars'
+        in
         let prepost =
           if FormalMap.is_formal rhs_base (fst extras)
              && match rhs_typ.desc with Typ.Tptr _ -> true | _ -> false
diff --git a/infer/tests/codetoanalyze/objc/uninit/uninit.m b/infer/tests/codetoanalyze/objc/uninit/uninit.m
new file mode 100644
index 000000000..17404fa8c
--- /dev/null
+++ b/infer/tests/codetoanalyze/objc/uninit/uninit.m
@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2017 - present Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+#include <Foundation/Foundation.h>
+
+@interface A : NSObject
+
+- (CGSize)sizeThatFits:(int)x;
+- (int)init_var_ok;
+
+@end
+
+@implementation A
+
+- (CGSize)sizeThatFits:(int)x {
+
+  CGSize s = CGSizeMake(x, x);
+
+  return s;
+}
+
+- (int)init_var_ok {
+  const CGSize labelSize = [self sizeThatFits:10];
+
+  return labelSize.height; // Here we should not report uninit
+}
+
+@end