xref: /llvm-project/libc/test/src/__support/HashTable/group_test.cpp (revision e59582b6f8f1be3e675866f6a5d661eb4c8ed448)
1 //===-- Unittests for control group ---------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "src/__support/HashTable/bitmask.h"
10 
11 #include "src/__support/CPP/bit.h"
12 #include "src/__support/macros/config.h"
13 #include "src/stdlib/rand.h"
14 #include "test/UnitTest/Test.h"
15 #include <stdint.h>
16 
17 namespace LIBC_NAMESPACE_DECL {
18 namespace internal {
19 
20 struct ByteArray {
21   alignas(Group) uint8_t data[sizeof(Group) + 1]{};
22 };
23 
24 TEST(LlvmLibcHashTableBitMaskTest, Match) {
25   // Any pair of targets have bit differences not only at the lowest bit.
26   // No False positive.
27   uint8_t targets[4] = {0x00, 0x11, 0xFF, 0x0F};
28   size_t count[4] = {0, 0, 0, 0};
29   size_t appearance[4][sizeof(Group)];
30   ByteArray array{};
31 
32   int data[sizeof(uintptr_t) / sizeof(int)];
33 
34   for (int &i : data)
35     i = rand();
36 
37   uintptr_t random = cpp::bit_cast<uintptr_t>(data);
38 
39   for (size_t i = 0; i < sizeof(Group); ++i) {
40     size_t choice = random % 4;
41     random /= 4;
42     array.data[i] = targets[choice];
43     appearance[choice][count[choice]++] = i;
44   }
45 
46   for (size_t t = 0; t < sizeof(targets); ++t) {
47     auto bitmask = Group::load(array.data).match_byte(targets[t]);
48     for (size_t i = 0; i < count[t]; ++i) {
49       size_t iterated = 0;
50       for (size_t position : bitmask) {
51         ASSERT_EQ(appearance[t][iterated], position);
52         iterated++;
53       }
54       ASSERT_EQ(count[t], iterated);
55     }
56   }
57 }
58 
59 TEST(LlvmLibcHashTableBitMaskTest, MaskAvailable) {
60   uint8_t values[3] = {0x00, 0x0F, 0x80};
61 
62   for (size_t i = 0; i < sizeof(Group); ++i) {
63     ByteArray array{};
64 
65     int data[sizeof(uintptr_t) / sizeof(int)];
66 
67     for (int &j : data)
68       j = rand();
69 
70     uintptr_t random = cpp::bit_cast<uintptr_t>(data);
71 
72     ASSERT_FALSE(Group::load(array.data).mask_available().any_bit_set());
73 
74     array.data[i] = 0x80;
75     for (size_t j = 0; j < sizeof(Group); ++j) {
76       if (i == j)
77         continue;
78       size_t sample_space = 2 + (j > i);
79       size_t choice = random % sample_space;
80       random /= sizeof(values);
81       array.data[j] = values[choice];
82     }
83 
84     auto mask = Group::load(array.data).mask_available();
85     ASSERT_TRUE(mask.any_bit_set());
86     ASSERT_EQ(mask.lowest_set_bit_nonzero(), i);
87   }
88 }
89 } // namespace internal
90 } // namespace LIBC_NAMESPACE_DECL
91