From bd22999950ace855f4c76cd878d7ee41c3275d0b Mon Sep 17 00:00:00 2001
From: Dulma Churchill <dulmarod@fb.com>
Date: Wed, 5 Oct 2016 05:48:34 -0700
Subject: [PATCH] [clang] Disable the condition always true or false check for
 clang as it is too noisy.

Reviewed By: jvillard

Differential Revision: D3967565

fbshipit-source-id: b81ea0c
---
 infer/src/backend/symExec.ml | 40 +++++++++++++++++++-----------------
 infer/src/base/Config.ml     |  2 ++
 infer/src/base/Config.mli    |  1 +
 3 files changed, 24 insertions(+), 19 deletions(-)

diff --git a/infer/src/backend/symExec.ml b/infer/src/backend/symExec.ml
index 8b6cf5f6b..16ef734ac 100644
--- a/infer/src/backend/symExec.ml
+++ b/infer/src/backend/symExec.ml
@@ -1039,25 +1039,27 @@ let rec sym_exec tenv current_pdesc _instr (prop_: Prop.normal Prop.t) path
   | Sil.Prune (cond, loc, true_branch, ik) ->
       let prop__ = Attribute.nullify_exp_with_objc_null tenv prop_ cond in
       let check_condition_always_true_false () =
-        let report_condition_always_true_false i =
-          let skip_loop = match ik with
-            | Sil.Ik_while | Sil.Ik_for ->
-                not (IntLit.iszero i) (* skip wile(1) and for (;1;) *)
-            | Sil.Ik_dowhile ->
-                true (* skip do..while *)
-            | Sil.Ik_land_lor ->
-                true (* skip subpart of a condition obtained from compilation of && and || *)
-            | _ -> false in
-          true_branch && not skip_loop in
-        match Prop.exp_normalize_prop tenv Prop.prop_emp cond with
-        | Exp.Const (Const.Cint i) when report_condition_always_true_false i ->
-            let node = State.get_node () in
-            let desc = Errdesc.explain_condition_always_true_false tenv i cond node loc in
-            let exn =
-              Exceptions.Condition_always_true_false (desc, not (IntLit.iszero i), __POS__) in
-            let pre_opt = State.get_normalized_pre (Abs.abstract_no_symop current_pname) in
-            Reporting.log_warning current_pname ?pre:pre_opt exn
-        | _ -> () in
+        if !Config.curr_language <> Config.Clang ||
+           Config.report_condition_always_true_in_clang then
+          let report_condition_always_true_false i =
+            let skip_loop = match ik with
+              | Sil.Ik_while | Sil.Ik_for ->
+                  not (IntLit.iszero i) (* skip wile(1) and for (;1;) *)
+              | Sil.Ik_dowhile ->
+                  true (* skip do..while *)
+              | Sil.Ik_land_lor ->
+                  true (* skip subpart of a condition obtained from compilation of && and || *)
+              | _ -> false in
+            true_branch && not skip_loop in
+          match Prop.exp_normalize_prop tenv Prop.prop_emp cond with
+          | Exp.Const (Const.Cint i) when report_condition_always_true_false i ->
+              let node = State.get_node () in
+              let desc = Errdesc.explain_condition_always_true_false tenv i cond node loc in
+              let exn =
+                Exceptions.Condition_always_true_false (desc, not (IntLit.iszero i), __POS__) in
+              let pre_opt = State.get_normalized_pre (Abs.abstract_no_symop current_pname) in
+              Reporting.log_warning current_pname ?pre:pre_opt exn
+          | _ -> () in
       if not Config.report_runtime_exceptions then
         check_already_dereferenced tenv current_pname cond prop__;
       check_condition_always_true_false ();
diff --git a/infer/src/base/Config.ml b/infer/src/base/Config.ml
index fb79740f4..824518f3c 100644
--- a/infer/src/base/Config.ml
+++ b/infer/src/base/Config.ml
@@ -107,6 +107,8 @@ let checks_disabled_by_default = [
 
 let clang_build_output_dir_name = "build_output"
 
+let report_condition_always_true_in_clang = false
+
 (** Experimental: if true do some specialized analysis of concurrent constructs. *)
 let csl_analysis = true
 
diff --git a/infer/src/base/Config.mli b/infer/src/base/Config.mli
index d34e4d2a2..2ca45db14 100644
--- a/infer/src/base/Config.mli
+++ b/infer/src/base/Config.mli
@@ -68,6 +68,7 @@ val buck_generated_folder : string
 val buck_infer_deps_file_name : string
 val captured_dir_name : string
 val checks_disabled_by_default : string list
+val report_condition_always_true_in_clang : bool
 val clang_build_output_dir_name : string
 val cpp_models_dir : string
 val csl_analysis : bool