[dead store objc] Whitelisting macro variables in dead stored checker for Objective-C

Reviewed By: sblackshear

Differential Revision: D6135723

fbshipit-source-id: e703345

Makefile

@@ -67,7 +67,7 @@ BUILD_SYSTEMS_TESTS += xcodebuild_no_xcpretty objc_getters_setters
 DIRECT_TESTS += \
   objc_frontend objc_errors objc_linters objc_ioslints \
 	objcpp_frontend objcpp_linters objc_linters-for-test-only objcpp_linters-for-test-only \
-	objc_linters-def-folder objc_checkers
+	objc_linters-def-folder objc_checkers objc_liveness
 ifneq ($(XCPRETTY),no)
 BUILD_SYSTEMS_TESTS += xcodebuild
 endif

infer/src/checkers/liveness.ml

@@ -61,6 +61,13 @@ end
 module CFG = ProcCfg.OneInstrPerNode (ProcCfg.Backward (ProcCfg.Exceptional))
 module Analyzer = AbstractInterpreter.Make (CFG) (TransferFunctions)
 
+let is_whitelisted_var var =
+  let whitelisted_vars = ["__assert_file__"; "__assert_fn__"] in
+  List.exists
+    ~f:(fun whitelisted_var -> String.equal whitelisted_var (Pvar.get_simplified_name var))
+    whitelisted_vars
+
+
 let checker {Callbacks.tenv; summary; proc_desc} : Specs.summary =
   let cfg = CFG.from_pdesc proc_desc in
   let invariant_map =
@@ -83,7 +90,8 @@ let checker {Callbacks.tenv; summary; proc_desc} : Specs.summary =
     | Sil.Store (Lvar pvar, _, _, loc)
       when not
              ( Pvar.is_frontend_tmp pvar || Pvar.is_return pvar || Pvar.is_global pvar
-             || Domain.mem (Var.of_pvar pvar) live_vars || is_captured_var pvar ) ->
+             || Domain.mem (Var.of_pvar pvar) live_vars || is_captured_var pvar
+             || is_whitelisted_var pvar ) ->
         let issue_id = IssueType.dead_store.unique_id in
         let message = F.asprintf "The value written to %a is never used" (Pvar.pp Pp.text) pvar in
         let ltr = [Errlog.make_trace_element 0 loc "Write of unused value" []] in
@@ -106,4 +114,3 @@ let checker {Callbacks.tenv; summary; proc_desc} : Specs.summary =
   in
   List.iter (CFG.nodes cfg) ~f:report_on_node ;
   summary
-

infer/tests/codetoanalyze/objc/liveness/Makefile

@@ -0,0 +1,19 @@
+# Copyright (c) 2016 - 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.
+
+TESTS_DIR = ../../..
+
+ANALYZER = checkers
+CLANG_OPTIONS = -x objective-c -c
+INFER_OPTIONS = --liveness-only --debug-exceptions --project-root $(TESTS_DIR)
+INFERPRINT_OPTIONS = --issues-tests
+
+SOURCES = $(wildcard *.m)
+
+include $(TESTS_DIR)/clang.make
+
+infer-out/report.json: $(MAKEFILE_LIST)

infer/tests/codetoanalyze/objc/liveness/NSParameterAssertExample.m

@@ -0,0 +1,47 @@
+/*
+ * 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.
+ */
+#import <Foundation/Foundation.h>
+
+@interface A : NSObject
+@end
+
+@implementation A
+
++ (void)foo {
+  if (!(1)) {
+    NSString* __assert_fn__ =
+        [NSString stringWithUTF8String:__PRETTY_FUNCTION__];
+    __assert_fn__ = __assert_fn__ ? __assert_fn__ : @"<Unknown Function>";
+    NSString* __assert_file__ = [NSString stringWithUTF8String:"A.m"];
+    __assert_file__ = __assert_file__ ? __assert_file__ : @"<Unknown File>";
+    [[NSAssertionHandler currentHandler]
+        handleFailureInFunction:__assert_fn__
+                           file:__assert_file__
+                     lineNumber:23
+                    description:(@"Hello")];
+  }
+}
+
++ (void)bar {
+  int phoneNumberError = 5;
+  int PhoneNumberNoError = 10;
+  if (!((phoneNumberError != PhoneNumberNoError))) {
+    NSString* __assert_file__ = [NSString stringWithUTF8String:"A.m"];
+    __assert_file__ = __assert_file__ ? __assert_file__ : @"<Unknown File>";
+    [[NSAssertionHandler currentHandler]
+        handleFailureInMethod:_cmd
+                       object:self
+                         file:__assert_file__
+                   lineNumber:12
+                  description:(@"Invalid parameter not satisfying: %@"),
+                              @"phoneNumberError != PhoneNumberNoError"];
+  }
+}
+
+@end