From 50252d31523bc6411572f290b688aa5b25476d3e Mon Sep 17 00:00:00 2001
From: Sungkeun Cho <scho@fb.com>
Date: Fri, 15 Nov 2019 04:51:13 -0800
Subject: [PATCH] [cost] Exclude bin-op-generated integers from control
 variables

Summary:
This diff excludes integer variables from control variables when their values are calculated by
binary operators.

Reviewed By: ezgicicek

Differential Revision: D18505826

fbshipit-source-id: 710533d4c
---
 .../bufferoverrun/bufferOverrunSemantics.ml   |  4 +--
 .../java/performance/IntTest.java             | 30 +++++++++++++++++++
 .../codetoanalyze/java/performance/issues.exp |  3 ++
 3 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/infer/src/bufferoverrun/bufferOverrunSemantics.ml b/infer/src/bufferoverrun/bufferOverrunSemantics.ml
index e93f93604..77519e442 100644
--- a/infer/src/bufferoverrun/bufferOverrunSemantics.ml
+++ b/infer/src/bufferoverrun/bufferOverrunSemantics.ml
@@ -159,9 +159,9 @@ let rec eval : Typ.IntegerWidths.t -> Exp.t -> Mem.t -> Val.t =
         match bop with
         | Binop.(PlusA _ | MinusA _ | MinusPP) ->
             Val.set_itv_updated_by_addition v
-        | Binop.(Mult _ | Div | Mod | Shiftlt | Shiftrt | BAnd | BXor | BOr) ->
+        | Binop.(Mult _ | Div | Mod | Shiftlt | Shiftrt) ->
             Val.set_itv_updated_by_multiplication v
-        | Binop.(PlusPI | MinusPI | Lt | Gt | Le | Ge | Eq | Ne | LAnd | LOr) ->
+        | Binop.(PlusPI | MinusPI | Lt | Gt | Le | Ge | Eq | Ne | LAnd | LOr | BAnd | BXor | BOr) ->
             Val.set_itv_updated_by_unknown v )
     | Exp.Const c ->
         eval_const integer_type_widths c
diff --git a/infer/tests/codetoanalyze/java/performance/IntTest.java b/infer/tests/codetoanalyze/java/performance/IntTest.java
index 2e4f6531f..9d344ce0e 100644
--- a/infer/tests/codetoanalyze/java/performance/IntTest.java
+++ b/infer/tests/codetoanalyze/java/performance/IntTest.java
@@ -19,4 +19,34 @@ class IntTest {
     Integer x = p; // call to valueOf
     for (int count = 0; count < x; count++) {}
   }
+
+  boolean unknown_bool;
+
+  void control_var_band_constant(int x, int y) {
+    int z;
+    for (int i = 0; i < 10; i++) {
+      if (unknown_bool) {
+        z = x & y;
+      } else {
+        z = x | y;
+      }
+      if (z == 0) {
+        break;
+      }
+    }
+  }
+
+  void control_var_band_add_constant_FP(int x, int y) {
+    int z;
+    for (int i = 0; i < 10; i++) {
+      if (unknown_bool) {
+        z = (x & y) + 1;
+      } else {
+        z = (x | y) + 1;
+      }
+      if (z == 0) {
+        break;
+      }
+    }
+  }
 }
diff --git a/infer/tests/codetoanalyze/java/performance/issues.exp b/infer/tests/codetoanalyze/java/performance/issues.exp
index 82ca3ebfe..2ef28afb0 100644
--- a/infer/tests/codetoanalyze/java/performance/issues.exp
+++ b/infer/tests/codetoanalyze/java/performance/issues.exp
@@ -116,6 +116,9 @@ codetoanalyze/java/performance/Cost_test_deps.java, codetoanalyze.java.performan
 codetoanalyze/java/performance/Cost_test_deps.java, codetoanalyze.java.performance.Cost_test_deps.two_loops():int, 7, EXPENSIVE_EXECUTION_TIME, no_bucket, ERROR, [with estimated cost 545, O(1), degree = 0]
 codetoanalyze/java/performance/EvilCfg.java, EvilCfg.foo(int,int,boolean):void, 0, INFINITE_EXECUTION_TIME, no_bucket, ERROR, [Unbounded loop,Loop at line 15]
 codetoanalyze/java/performance/FieldAccess.java, codetoanalyze.java.performance.FieldAccess.iterate_upto_field_size(codetoanalyze.java.performance.FieldAccess$Test):void, 1, EXPENSIVE_EXECUTION_TIME, no_bucket, ERROR, [with estimated cost 2 + 6 ⋅ test.a, O(test.a), degree = 1,{test.a},Loop at line 16]
+codetoanalyze/java/performance/IntTest.java, IntTest.control_var_band_add_constant_FP(int,int):void, 0, INFINITE_EXECUTION_TIME, no_bucket, ERROR, [Unbounded loop,Loop at line 41]
+codetoanalyze/java/performance/IntTest.java, IntTest.control_var_band_add_constant_FP(int,int):void, 4, INTEGER_OVERFLOW_L5, no_bucket, ERROR, [<LHS trace>,Parameter `x`,Binary operation: ([-oo, +oo] + 1):signed32]
+codetoanalyze/java/performance/IntTest.java, IntTest.control_var_band_add_constant_FP(int,int):void, 6, INTEGER_OVERFLOW_L5, no_bucket, ERROR, [<LHS trace>,Parameter `x`,Binary operation: ([-oo, +oo] + 1):signed32]
 codetoanalyze/java/performance/IntTest.java, IntTest.intValue_linear(java.lang.Integer):void, 1, EXPENSIVE_EXECUTION_TIME, no_bucket, ERROR, [with estimated cost 2 + 5 ⋅ mKBytesToSend + 3 ⋅ (1+max(0, mKBytesToSend)), O(mKBytesToSend), degree = 1,{1+max(0, mKBytesToSend)},Loop at line 9,{mKBytesToSend},Loop at line 9]
 codetoanalyze/java/performance/IntTest.java, IntTest.static_Integer_top():void, 0, INFINITE_EXECUTION_TIME, no_bucket, ERROR, [Unbounded loop,Loop at line 15]
 codetoanalyze/java/performance/IntTest.java, IntTest.static_Integer_top():void, 1, INTEGER_OVERFLOW_L5, no_bucket, ERROR, [<LHS trace>,Assignment,Binary operation: ([0, +oo] + 1):signed32]