src/base/atomicops_unittest.cc

   1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/atomicops.h"
   6
   7 #include <stdint.h>
   8 #include <string.h>
   9
  10 #include "testing/gtest/include/gtest/gtest.h"
  11
  12 template <class AtomicType>
  13 static void TestAtomicIncrement() {
  14   // For now, we just test single threaded execution
  15
  16   // use a guard value to make sure the NoBarrier_AtomicIncrement doesn't go
  17   // outside the expected address bounds.  This is in particular to
  18   // test that some future change to the asm code doesn't cause the
  19   // 32-bit NoBarrier_AtomicIncrement doesn't do the wrong thing on 64-bit
  20   // machines.
  21   struct {
  22     AtomicType prev_word;
  23     AtomicType count;
  24     AtomicType next_word;
  25   } s;
  26
  27   AtomicType prev_word_value, next_word_value;
  28   memset(&prev_word_value, 0xFF, sizeof(AtomicType));
  29   memset(&next_word_value, 0xEE, sizeof(AtomicType));
  30
  31   s.prev_word = prev_word_value;
  32   s.count = 0;
  33   s.next_word = next_word_value;
  34
  35   EXPECT_EQ(base::subtle::NoBarrier_AtomicIncrement(&s.count, 1), 1);
  36   EXPECT_EQ(s.count, 1);
  37   EXPECT_EQ(s.prev_word, prev_word_value);
  38   EXPECT_EQ(s.next_word, next_word_value);
  39
  40   EXPECT_EQ(base::subtle::NoBarrier_AtomicIncrement(&s.count, 2), 3);
  41   EXPECT_EQ(s.count, 3);
  42   EXPECT_EQ(s.prev_word, prev_word_value);
  43   EXPECT_EQ(s.next_word, next_word_value);
  44
  45   EXPECT_EQ(base::subtle::NoBarrier_AtomicIncrement(&s.count, 3), 6);
  46   EXPECT_EQ(s.count, 6);
  47   EXPECT_EQ(s.prev_word, prev_word_value);
  48   EXPECT_EQ(s.next_word, next_word_value);
  49
  50   EXPECT_EQ(base::subtle::NoBarrier_AtomicIncrement(&s.count, -3), 3);
  51   EXPECT_EQ(s.count, 3);
  52   EXPECT_EQ(s.prev_word, prev_word_value);
  53   EXPECT_EQ(s.next_word, next_word_value);
  54
  55   EXPECT_EQ(base::subtle::NoBarrier_AtomicIncrement(&s.count, -2), 1);
  56   EXPECT_EQ(s.count, 1);
  57   EXPECT_EQ(s.prev_word, prev_word_value);
  58   EXPECT_EQ(s.next_word, next_word_value);
  59
  60   EXPECT_EQ(base::subtle::NoBarrier_AtomicIncrement(&s.count, -1), 0);
  61   EXPECT_EQ(s.count, 0);
  62   EXPECT_EQ(s.prev_word, prev_word_value);
  63   EXPECT_EQ(s.next_word, next_word_value);
  64
  65   EXPECT_EQ(base::subtle::NoBarrier_AtomicIncrement(&s.count, -1), -1);
  66   EXPECT_EQ(s.count, -1);
  67   EXPECT_EQ(s.prev_word, prev_word_value);
  68   EXPECT_EQ(s.next_word, next_word_value);
  69
  70   EXPECT_EQ(base::subtle::NoBarrier_AtomicIncrement(&s.count, -4), -5);
  71   EXPECT_EQ(s.count, -5);
  72   EXPECT_EQ(s.prev_word, prev_word_value);
  73   EXPECT_EQ(s.next_word, next_word_value);
  74
  75   EXPECT_EQ(base::subtle::NoBarrier_AtomicIncrement(&s.count, 5), 0);
  76   EXPECT_EQ(s.count, 0);
  77   EXPECT_EQ(s.prev_word, prev_word_value);
  78   EXPECT_EQ(s.next_word, next_word_value);
  79 }
  80
  81
  82 #define NUM_BITS(T) (sizeof(T) * 8)
  83
  84
  85 template <class AtomicType>
  86 static void TestCompareAndSwap() {
  87   AtomicType value = 0;
  88   AtomicType prev = base::subtle::NoBarrier_CompareAndSwap(&value, 0, 1);
  89   EXPECT_EQ(1, value);
  90   EXPECT_EQ(0, prev);
  91
  92   // Use test value that has non-zero bits in both halves, more for testing
  93   // 64-bit implementation on 32-bit platforms.
  94   const AtomicType k_test_val = (static_cast<uint64_t>(1) <<
  95                                  (NUM_BITS(AtomicType) - 2)) + 11;
  96   value = k_test_val;
  97   prev = base::subtle::NoBarrier_CompareAndSwap(&value, 0, 5);
  98   EXPECT_EQ(k_test_val, value);
  99   EXPECT_EQ(k_test_val, prev);
 100
 101   value = k_test_val;
 102   prev = base::subtle::NoBarrier_CompareAndSwap(&value, k_test_val, 5);
 103   EXPECT_EQ(5, value);
 104   EXPECT_EQ(k_test_val, prev);
 105 }
 106
 107
 108 template <class AtomicType>
 109 static void TestAtomicExchange() {
 110   AtomicType value = 0;
 111   AtomicType new_value = base::subtle::NoBarrier_AtomicExchange(&value, 1);
 112   EXPECT_EQ(1, value);
 113   EXPECT_EQ(0, new_value);
 114
 115   // Use test value that has non-zero bits in both halves, more for testing
 116   // 64-bit implementation on 32-bit platforms.
 117   const AtomicType k_test_val = (static_cast<uint64_t>(1) <<
 118                                  (NUM_BITS(AtomicType) - 2)) + 11;
 119   value = k_test_val;
 120   new_value = base::subtle::NoBarrier_AtomicExchange(&value, k_test_val);
 121   EXPECT_EQ(k_test_val, value);
 122   EXPECT_EQ(k_test_val, new_value);
 123
 124   value = k_test_val;
 125   new_value = base::subtle::NoBarrier_AtomicExchange(&value, 5);
 126   EXPECT_EQ(5, value);
 127   EXPECT_EQ(k_test_val, new_value);
 128 }
 129
 130
 131 template <class AtomicType>
 132 static void TestAtomicIncrementBounds() {
 133   // Test at rollover boundary between int_max and int_min
 134   AtomicType test_val = (static_cast<uint64_t>(1) <<
 135                          (NUM_BITS(AtomicType) - 1));
 136   AtomicType value = -1 ^ test_val;
 137   AtomicType new_value = base::subtle::NoBarrier_AtomicIncrement(&value, 1);
 138   EXPECT_EQ(test_val, value);
 139   EXPECT_EQ(value, new_value);
 140
 141   base::subtle::NoBarrier_AtomicIncrement(&value, -1);
 142   EXPECT_EQ(-1 ^ test_val, value);
 143
 144   // Test at 32-bit boundary for 64-bit atomic type.
 145   test_val = static_cast<uint64_t>(1) << (NUM_BITS(AtomicType) / 2);
 146   value = test_val - 1;
 147   new_value = base::subtle::NoBarrier_AtomicIncrement(&value, 1);
 148   EXPECT_EQ(test_val, value);
 149   EXPECT_EQ(value, new_value);
 150
 151   base::subtle::NoBarrier_AtomicIncrement(&value, -1);
 152   EXPECT_EQ(test_val - 1, value);
 153 }
 154
 155 // Return an AtomicType with the value 0xa5a5a5..
 156 template <class AtomicType>
 157 static AtomicType TestFillValue() {
 158   AtomicType val = 0;
 159   memset(&val, 0xa5, sizeof(AtomicType));
 160   return val;
 161 }
 162
 163 // This is a simple sanity check that values are correct. Not testing
 164 // atomicity
 165 template <class AtomicType>
 166 static void TestStore() {
 167   const AtomicType kVal1 = TestFillValue<AtomicType>();
 168   const AtomicType kVal2 = static_cast<AtomicType>(-1);
 169
 170   AtomicType value;
 171
 172   base::subtle::NoBarrier_Store(&value, kVal1);
 173   EXPECT_EQ(kVal1, value);
 174   base::subtle::NoBarrier_Store(&value, kVal2);
 175   EXPECT_EQ(kVal2, value);
 176
 177   base::subtle::Acquire_Store(&value, kVal1);
 178   EXPECT_EQ(kVal1, value);
 179   base::subtle::Acquire_Store(&value, kVal2);
 180   EXPECT_EQ(kVal2, value);
 181
 182   base::subtle::Release_Store(&value, kVal1);
 183   EXPECT_EQ(kVal1, value);
 184   base::subtle::Release_Store(&value, kVal2);
 185   EXPECT_EQ(kVal2, value);
 186 }
 187
 188 // This is a simple sanity check that values are correct. Not testing
 189 // atomicity
 190 template <class AtomicType>
 191 static void TestLoad() {
 192   const AtomicType kVal1 = TestFillValue<AtomicType>();
 193   const AtomicType kVal2 = static_cast<AtomicType>(-1);
 194
 195   AtomicType value;
 196
 197   value = kVal1;
 198   EXPECT_EQ(kVal1, base::subtle::NoBarrier_Load(&value));
 199   value = kVal2;
 200   EXPECT_EQ(kVal2, base::subtle::NoBarrier_Load(&value));
 201
 202   value = kVal1;
 203   EXPECT_EQ(kVal1, base::subtle::Acquire_Load(&value));
 204   value = kVal2;
 205   EXPECT_EQ(kVal2, base::subtle::Acquire_Load(&value));
 206
 207   value = kVal1;
 208   EXPECT_EQ(kVal1, base::subtle::Release_Load(&value));
 209   value = kVal2;
 210   EXPECT_EQ(kVal2, base::subtle::Release_Load(&value));
 211 }
 212
 213 TEST(AtomicOpsTest, Inc) {
 214   TestAtomicIncrement<base::subtle::Atomic32>();
 215   TestAtomicIncrement<base::subtle::AtomicWord>();
 216 }
 217
 218 TEST(AtomicOpsTest, CompareAndSwap) {
 219   TestCompareAndSwap<base::subtle::Atomic32>();
 220   TestCompareAndSwap<base::subtle::AtomicWord>();
 221 }
 222
 223 TEST(AtomicOpsTest, Exchange) {
 224   TestAtomicExchange<base::subtle::Atomic32>();
 225   TestAtomicExchange<base::subtle::AtomicWord>();
 226 }
 227
 228 TEST(AtomicOpsTest, IncrementBounds) {
 229   TestAtomicIncrementBounds<base::subtle::Atomic32>();
 230   TestAtomicIncrementBounds<base::subtle::AtomicWord>();
 231 }
 232
 233 TEST(AtomicOpsTest, Store) {
 234   TestStore<base::subtle::Atomic32>();
 235   TestStore<base::subtle::AtomicWord>();
 236 }
 237
 238 TEST(AtomicOpsTest, Load) {
 239   TestLoad<base::subtle::Atomic32>();
 240   TestLoad<base::subtle::AtomicWord>();
 241 }