Never call destructor on delete expression

Summary:
This call was producing confusing false positives when deleted object was possible to be null.
Changing frontend to add that check is not trivial so I turned it off for now (we don't handle
destructors in other cases anyway)

Reviewed By: dulmarod

Differential Revision: D3509354

fbshipit-source-id: c23dc81

infer/src/clang/cTrans.ml

@@ -2134,19 +2134,25 @@ struct
     let result_trans_param = exec_with_self_exception instruction trans_state_param param in
     let exp = extract_exp_from_list result_trans_param.exps
         "WARNING: There should be one expression to delete. \n" in
-    let deleted_type = delete_expr_info.Clang_ast_t.xdei_destroyed_type in
-    (* create stmt_info with new pointer so that destructor call doesn't create a node *)
-    let destruct_stmt_info = { stmt_info with
-                               Clang_ast_t.si_pointer = Ast_utils.get_fresh_pointer () } in
-    (* use empty_res_trans to avoid ending up with same instruction twice *)
-    (* otherwise it would happen due to structutre of all_res_trans *)
-    let this_res_trans_destruct = { empty_res_trans with exps = result_trans_param.exps } in
-    let destruct_res_trans = cxx_destructor_call_trans trans_state_pri destruct_stmt_info
-        this_res_trans_destruct deleted_type in
-    (* function is void *)
     let call_instr = Sil.Call ([], (Sil.Const (Sil.Cfun fname)), [exp], sil_loc, Sil.cf_default) in
     let call_res_trans = { empty_res_trans with instrs = [call_instr] } in
-    let all_res_trans = [ result_trans_param; destruct_res_trans; call_res_trans] in
+    let all_res_trans = if false then
+        (* FIXME (t10135167): call destructor on deleted pointer if it's not null *)
+        (* Right now it's dead code hidden by the 'false' flag *)
+        let deleted_type = delete_expr_info.Clang_ast_t.xdei_destroyed_type in
+        (* create stmt_info with new pointer so that destructor call doesn't create a node *)
+        let destruct_stmt_info = { stmt_info with
+                                   Clang_ast_t.si_pointer = Ast_utils.get_fresh_pointer () } in
+        (* use empty_res_trans to avoid ending up with same instruction twice *)
+        (* otherwise it would happen due to structutre of all_res_trans *)
+        let this_res_trans_destruct = { empty_res_trans with exps = result_trans_param.exps } in
+        let destruct_res_trans = cxx_destructor_call_trans trans_state_pri destruct_stmt_info
+            this_res_trans_destruct deleted_type in
+        [ result_trans_param; destruct_res_trans; call_res_trans]
+        (* --- END OF DEAD CODE --- *)
+      else
+        [ result_trans_param; call_res_trans] in
+
     let res_trans = PriorityNode.compute_results_to_parent trans_state_pri sil_loc
         "Call delete" stmt_info all_res_trans in
     { res_trans with exps = [] }

infer/tests/codetoanalyze/cpp/frontend/destructors/call_on_delete.cpp.dot

@@ -11,7 +11,7 @@ digraph iCFG {
 	
 
 	 6 -> 8 ;
-5 [label="5:  Call delete \n   n$0=*&x:class X * [line 14]\n  n$1=*n$0:class X  [line 14]\n  _fun_X_~X(n$0:class X *) [line 14]\n  _fun___delete(n$0:class X *) [line 14]\n " shape="box"]
+5 [label="5:  Call delete \n   n$0=*&x:class X * [line 14]\n  _fun___delete(n$0:class X *) [line 14]\n " shape="box"]
 	
 
 	 5 -> 4 ;

infer/tests/codetoanalyze/cpp/frontend/methods/virtual_methods.cpp.dot

@@ -1,10 +1,10 @@
 /* @generated */
 digraph iCFG {
-53 [label="53:  DeclStmt \n   n$2=_fun___new(sizeof(class Triangle ):unsigned long ) [line 71]\n  _fun_Triangle_Triangle(n$2:class Triangle *) [line 71]\n  *&trgl:class Triangle *=n$2 [line 71]\n " shape="box"]
+53 [label="53:  DeclStmt \n   n$1=_fun___new(sizeof(class Triangle ):unsigned long ) [line 71]\n  _fun_Triangle_Triangle(n$1:class Triangle *) [line 71]\n  *&trgl:class Triangle *=n$1 [line 71]\n " shape="box"]
 	
 
 	 53 -> 52 ;
-52 [label="52:  Call delete \n   n$0=*&trgl:class Polygon * [line 72]\n  n$1=*n$0:class Polygon  [line 72]\n  _fun_Polygon_~Polygon(n$0:class Polygon *) virtual [line 72]\n  _fun___delete(n$0:class Polygon *) [line 72]\n " shape="box"]
+52 [label="52:  Call delete \n   n$0=*&trgl:class Polygon * [line 72]\n  _fun___delete(n$0:class Polygon *) [line 72]\n " shape="box"]
 	
 
 	 52 -> 51 ;