From aca39195f8889c7a0c60a8b4ede1a1a2c47e2296 Mon Sep 17 00:00:00 2001
From: Dulma Churchill <dulmarod@fb.com>
Date: Mon, 19 Mar 2018 04:30:31 -0700
Subject: [PATCH] [retain cycles] Use decompiled expressions in the retain
 cycle message

Reviewed By: mbouaziz

Differential Revision: D7292599

fbshipit-source-id: 8e6b0ed
---
 infer/src/IR/DecompiledExp.ml     | 26 +++++++++++++++++---------
 infer/src/backend/RetainCycles.ml | 24 ++++++++++++++++--------
 2 files changed, 33 insertions(+), 17 deletions(-)

diff --git a/infer/src/IR/DecompiledExp.ml b/infer/src/IR/DecompiledExp.ml
index 298bd1559..583a99ef2 100644
--- a/infer/src/IR/DecompiledExp.ml
+++ b/infer/src/IR/DecompiledExp.ml
@@ -40,6 +40,10 @@ let split_var_clang var_name =
   match String.rsplit2 ~on:'.' var_name with Some (_, name) -> name | _ -> var_name
 
 
+let builtin_functions_to_string pn =
+  if Typ.Procname.equal pn BuiltinDecl.__objc_alloc_no_fail then Some "alloc" else None
+
+
 (** convert a dexp to a string *)
 let rec to_string = function
   | Darray (de1, de2) ->
@@ -49,16 +53,20 @@ let rec to_string = function
   | Dconst Cfun pn
     -> (
       let procname_str = Typ.Procname.to_simplified_string pn in
-      match pn with
-      | Typ.Procname.ObjC_Cpp {kind= ObjCInstanceMethod}
-      | Typ.Procname.ObjC_Cpp {kind= ObjCClassMethod} -> (
-        match String.lsplit2 ~on:':' procname_str with
-        | Some (base_name, _) ->
-            base_name
-        | None ->
+      match builtin_functions_to_string pn with
+      | Some str ->
+          str
+      | None ->
+        match pn with
+        | Typ.Procname.ObjC_Cpp {kind= ObjCInstanceMethod}
+        | Typ.Procname.ObjC_Cpp {kind= ObjCClassMethod} -> (
+          match String.lsplit2 ~on:':' procname_str with
+          | Some (base_name, _) ->
+              base_name
+          | None ->
+              procname_str )
+        | _ ->
             procname_str )
-      | _ ->
-          procname_str )
   | Dconst c ->
       Const.to_string c
   | Dderef de ->
diff --git a/infer/src/backend/RetainCycles.ml b/infer/src/backend/RetainCycles.ml
index 87e51a3aa..c92abf01b 100644
--- a/infer/src/backend/RetainCycles.ml
+++ b/infer/src/backend/RetainCycles.ml
@@ -18,11 +18,20 @@ let desc_retain_cycle tenv (cycle: RetainCyclesType.t) =
     let index = index_ + 1 in
     let node = State.get_node () in
     let from_exp_str edge_obj =
-      ignore (Errdesc.find_outermost_dereference tenv node edge_obj.rc_from.rc_node_exp) ;
-      (* | Some de ->
-          DecompiledExp.to_string de
-      | None -> TODO (T26707784): fix issues with DecompiledExp.to_string *)
-      Format.sprintf "(object of type %s)" (Typ.to_string edge_obj.rc_from.rc_node_typ)
+      let type_str =
+        MF.monospaced_to_string (Format.sprintf "%s*" (Typ.to_string edge_obj.rc_from.rc_node_typ))
+      in
+      match Errdesc.find_outermost_dereference tenv node edge_obj.rc_from.rc_node_exp with
+      | Some de
+        -> (
+          let decomp = DecompiledExp.to_string de in
+          match de with
+          | DecompiledExp.Dretcall _ ->
+              Format.sprintf "object %s of type %s" decomp type_str
+          | _ ->
+              Format.sprintf "%s of type %s" (MF.monospaced_to_string decomp) type_str )
+      | None ->
+          Format.sprintf "object of type %s" type_str
     in
     let location_str =
       match edge with
@@ -38,9 +47,8 @@ let desc_retain_cycle tenv (cycle: RetainCyclesType.t) =
     let cycle_item_str =
       match edge with
       | Object obj ->
-          MF.monospaced_to_string
-            (Format.sprintf "%s->%s" (from_exp_str obj)
-               (Typ.Fieldname.to_string obj.rc_field.rc_field_name))
+          Format.sprintf "%s --> %s" (from_exp_str obj)
+            (MF.monospaced_to_string (Typ.Fieldname.to_string obj.rc_field.rc_field_name))
       | Block (_, var) ->
           Format.sprintf "a block that captures %s" (MF.monospaced_to_string (Pvar.to_string var))
     in