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/*
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/
import java.util.ArrayList;
import java.util.Iterator;
class Localities {
// @pure
boolean contains_pure(Integer i, ArrayList<Integer> list) {
Iterator<Integer> listIterator = list.iterator();
while (listIterator.hasNext()) {
Integer el = listIterator.next();
if (i.equals(el)) {
return true;
}
}
return false;
}
// @mod:{list}
void makeAllZero_impure(ArrayList<Foo> list) {
Iterator<Foo> listIterator = list.iterator();
while (listIterator.hasNext()) {
Foo foo = listIterator.next();
foo.x = 0;
}
}
// @mod:{list}
void incrementAll_impure(ArrayList<Foo> list) {
Iterator<Foo> listIterator = list.iterator();
while (listIterator.hasNext()) {
Foo foo = listIterator.next();
foo.inc_impure();
}
}
// @pure
void call_impure_with_fresh_args_pure() {
ArrayList<Foo> list = new ArrayList<Foo>();
makeAllZero_impure(list);
}
class Bar {
int p;
}
class Foo {
int x;
Bar bar;
// @mod:{this}
void inc_impure() {
x++;
}
}
class Counter {
int i = 0;
// @mod:{this}
// only modifies fields of its receiver object
void inc_impure() {
i++;
}
// @pure, @loc:{}
int get_i_pure() {
return i;
}
}
// @pure, @loc:{}
int length_pure(ArrayList<Integer> list) {
Counter c = new Counter();
for (Integer i : list) {
c.inc_impure();
}
return c.i;
}
class HasCounter {
Counter counter = new Counter();
// @loc:{this}
Counter getCounter_pure() {
return counter;
}
}
// @loc:{}
public static int[] setFreshArrayEntry_pure(int index, int value) {
int[] arr = new int[] {1, 2, 3};
if (index > 0) {
arr[index % 3] = value;
}
return arr;
}
// @loc: T
private int newHashCode_impure() {
return new Object().hashCode();
}
// @loc:{c}
HasCounter mkHC_pure(Counter c) {
HasCounter hc = new HasCounter();
hc.counter = c;
return hc;
}
// @mod:{array}, @loc:{array,f}
Foo get_f_impure(Foo[] array, int i, Foo f) {
Foo tmp = array[i];
tmp.x = f.x;
return tmp;
}
// @mod:{array}, @loc:{array,f}
Foo[] get_array_impure(Foo[] array, int i, Foo f) {
Foo tmp = array[i];
tmp.x = f.x;
return array;
}
// @mod:{array}, @loc:{p}
Bar get_foo_via_tmp_impure(Foo[] array, int i, Foo f, Foo p) {
Foo tmp = array[i];
tmp.bar = f.bar;
Foo tmp2 = tmp;
tmp2.bar = p.bar;
return tmp.bar;
}
// @pure, @loc:{}
boolean copy_ref_pure(int[] a, int b) {
int[] local = a; // copy reference
a = new int[1]; // a becomes fresh
a[0] = local[0]; // not modification
return true;
}
// @mod:{a}, @loc:{}
boolean copy_ref_impure(int[] a, int b) {
int[] local = a; // copy reference
a = new int[1]; // overwrite reference
a[0] = local[0]; // not modification
local[0] = b; // modify arg a
b = a[0]; // not modification
return true;
}
void swap_pure(Object s1, Object s2) {
Object temp = s2;
s2 = s1;
s1 = temp;
}
// @mod:{list}
void modify_first_el_impure(ArrayList<Foo> list) {
Foo first = list.get(0);
first.x = 0;
}
Foo get_first_pure(ArrayList<Foo> list) {
return list.get(0);
}
// @mod:{list}
void modify_via_call_impure(ArrayList<Foo> list) {
Foo first = get_first_pure(list);
first.inc_impure();
}
[pulse] Only propagate existing WrittenTo attributes at function calls Summary: Previously, at each function call, we added a `WrittenTo` attribute for applying the address of the actuals. However, this results in mistakenly considering each function application that inspects its argument as impure. Instead, we should only propagate `WrittenTo` if the actuals have already `WrittenTo` attributes. For instance, for the following functions ``` public static boolean is_null(Byte a) { return a == null; } public static boolean call_is_null(Byte a) { return is_null(a); } ``` We used to get the following pulse summary for `call_is_null` (showing only one of the disjuncts): ``` #0: PRE: { roots={ &a=v1 }; mem ={ v1 -> { * -> v2 } }; attrs={ v1 -> { MustBeValid }, v2 -> { Arith =null, BoItv ([max(0, v2), min(0, v2)]) } };} POST: { roots={ &a=v1, &return=v8 }; mem ={ v1 -> { * -> v2 }, v8 -> { * -> v4 } }; attrs={ v2 -> { Arith =null, BoItv ([max(0, v2), min(0, v2)]), WrittenTo-----------WRONG }, v4 -> { Arith =1, BoItv (1), Invalid ConstantDereference(is the constant 1), WrittenTo-----------WRONG }, v8 -> { WrittenTo } };} SKIPPED_CALLS: { } ``` where we mistakenly recorded a `WrittenTo` for `v2` (what `a` points to). As a result, we considered `call_is_null` as impure :( This diff fixes that since the callee `is_null` doesn't have any `WrittenTo` attributes for its parameter `a`. So, we don't propagate `WrittenTo` and get the following summary ``` #0: PRE: { roots={ &a=v1 }; mem ={ v1 -> { * -> v2 } }; attrs={ v1 -> { MustBeValid }, v2 -> { Arith =null, BoItv ([max(0, v2), min(0, v2)]) } };} POST: { roots={ &a=v1, &return=v8 }; mem ={ v1 -> { * -> v2 }, v8 -> { * -> v4 } }; attrs={ v2 -> { Arith =null, BoItv ([max(0, v2), min(0, v2)]) }, v4 -> { Arith =1, BoItv (1), Invalid ConstantDereference(is the constant 1) }, v8 -> { WrittenTo } };} SKIPPED_CALLS: { } ``` Reviewed By: skcho Differential Revision: D20490102 fbshipit-source-id: 253d8ef64
5 years ago
public static boolean is_null_pure(Byte a) {
return a == null;
}
public static boolean call_is_null_pure(Byte a) {
return is_null_pure(a);
}
}