Add the annotation @IgnoreAllocations to stop tracking allocations whenever useless

Summary:public
Add support for stopping allocation tracking on methods annotated with IgnoreAllocations

Reviewed By: cristianoc

Differential Revision: D2979563

fb-gh-sync-id: 2699375
shipit-source-id: 2699375

infer/annotations/com/facebook/infer/annotation/IgnoreAllocations.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright (c) 2015 - 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.
+ */
+
+package com.facebook.infer.annotation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Retention(RetentionPolicy.CLASS)
+@Target(ElementType.METHOD)
+public @interface IgnoreAllocations {}

infer/src/checkers/annotations.ml

@@ -111,6 +111,7 @@ let verify_annotation = "com.facebook.infer.annotation.Verify"
 let expensive = "Expensive"
 let performance_critical = "PerformanceCritical"
 let no_allocation = "NoAllocation"
+let ignore_allocations = "IgnoreAllocations"
 
 let ia_is_nullable ia =
   ia_ends_with ia nullable
@@ -158,6 +159,9 @@ let ia_is_performance_critical ia =
 let ia_is_no_allocation ia =
   ia_ends_with ia no_allocation
 
+let ia_is_ignore_allocations ia =
+  ia_ends_with ia ignore_allocations
+
 type annotation =
   | Nullable
   | Present

infer/src/checkers/annotations.mli

@@ -74,6 +74,7 @@ val ia_is_verify : Sil.item_annotation -> bool
 val ia_is_expensive : Sil.item_annotation -> bool
 val ia_is_performance_critical : Sil.item_annotation -> bool
 val ia_is_no_allocation : Sil.item_annotation -> bool
+val ia_is_ignore_allocations : Sil.item_annotation -> bool
 
 val ia_iter : (Sil.annotation -> unit) -> Sil.item_annotation -> unit
 

infer/src/checkers/performanceCritical.ml

@@ -141,8 +141,9 @@ let method_allocates tenv pname =
     | Some { Specs.allocations } ->
         allocations <> []
     | None -> false in
-  is_allocator tenv pname
-  || allocates ()
+  not (check_method Annotations.ia_is_ignore_allocations pname)
+  && (is_allocator tenv pname
+      || allocates ())
 
 
 let lookup_location pname =

infer/tests/codetoanalyze/java/checkers/NoAllocationExample.java

@@ -10,6 +10,7 @@
 package codetoanalyze.java.checkers;
 
 import com.facebook.infer.annotation.NoAllocation;
+import com.facebook.infer.annotation.IgnoreAllocations;
 
 public class NoAllocationExample {
 
@@ -50,4 +51,14 @@ public class NoAllocationExample {
     throwsException();
   }
 
+  @IgnoreAllocations
+  void acceptableAllocation() {
+    new Object();
+  }
+
+  @NoAllocation
+  void onlyAllocatesInAcceptableWay() {
+    acceptableAllocation();
+  }
+
 }