base/atomicops_unittest.cc

   1 // Copyright 2011 The Chromium Authors
   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   // Verify that CAS will *not* change "value" if it doesn't match the
  93   // expected  number. CAS will always return the actual value of the
  94   // variable from before any change.
  95   AtomicType fail = base::subtle::NoBarrier_CompareAndSwap(&value, 0, 2);
  96   EXPECT_EQ(1, value);
  97   EXPECT_EQ(1, fail);
  98
  99   // Use test value that has non-zero bits in both halves, more for testing
 100   // 64-bit implementation on 32-bit platforms.
 101   const AtomicType k_test_val = (static_cast<uint64_t>(1) <<
 102                                  (NUM_BITS(AtomicType) - 2)) + 11;
 103   value = k_test_val;
 104   prev = base::subtle::NoBarrier_CompareAndSwap(&value, 0, 5);
 105   EXPECT_EQ(k_test_val, value);
 106   EXPECT_EQ(k_test_val, prev);
 107
 108   value = k_test_val;
 109   prev = base::subtle::NoBarrier_CompareAndSwap(&value, k_test_val, 5);
 110   EXPECT_EQ(5, value);
 111   EXPECT_EQ(k_test_val, prev);
 112 }
 113
 114
 115 template <class AtomicType>
 116 static void TestAtomicExchange() {
 117   AtomicType value = 0;
 118   AtomicType new_value = base::subtle::NoBarrier_AtomicExchange(&value, 1);
 119   EXPECT_EQ(1, value);
 120   EXPECT_EQ(0, new_value);
 121
 122   // Use test value that has non-zero bits in both halves, more for testing
 123   // 64-bit implementation on 32-bit platforms.
 124   const AtomicType k_test_val = (static_cast<uint64_t>(1) <<
 125                                  (NUM_BITS(AtomicType) - 2)) + 11;
 126   value = k_test_val;
 127   new_value = base::subtle::NoBarrier_AtomicExchange(&value, k_test_val);
 128   EXPECT_EQ(k_test_val, value);
 129   EXPECT_EQ(k_test_val, new_value);
 130
 131   value = k_test_val;
 132   new_value = base::subtle::NoBarrier_AtomicExchange(&value, 5);
 133   EXPECT_EQ(5, value);
 134   EXPECT_EQ(k_test_val, new_value);
 135 }
 136
 137
 138 template <class AtomicType>
 139 static void TestAtomicIncrementBounds() {
 140   // Test at rollover boundary between int_max and int_min
 141   AtomicType test_val = (static_cast<uint64_t>(1) <<
 142                          (NUM_BITS(AtomicType) - 1));
 143   AtomicType value = -1 ^ test_val;
 144   AtomicType new_value = base::subtle::NoBarrier_AtomicIncrement(&value, 1);
 145   EXPECT_EQ(test_val, value);
 146   EXPECT_EQ(value, new_value);
 147
 148   base::subtle::NoBarrier_AtomicIncrement(&value, -1);
 149   EXPECT_EQ(-1 ^ test_val, value);
 150
 151   // Test at 32-bit boundary for 64-bit atomic type.
 152   test_val = static_cast<uint64_t>(1) << (NUM_BITS(AtomicType) / 2);
 153   value = test_val - 1;
 154   new_value = base::subtle::NoBarrier_AtomicIncrement(&value, 1);
 155   EXPECT_EQ(test_val, value);
 156   EXPECT_EQ(value, new_value);
 157
 158   base::subtle::NoBarrier_AtomicIncrement(&value, -1);
 159   EXPECT_EQ(test_val - 1, value);
 160 }
 161
 162 // Return an AtomicType with the value 0xa5a5a5..
 163 template <class AtomicType>
 164 static AtomicType TestFillValue() {
 165   AtomicType val = 0;
 166   memset(&val, 0xa5, sizeof(AtomicType));
 167   return val;
 168 }
 169
 170 // This is a simple sanity check that values are correct. Not testing
 171 // atomicity
 172 template <class AtomicType>
 173 static void TestStore() {
 174   const AtomicType kVal1 = TestFillValue<AtomicType>();
 175   const AtomicType kVal2 = static_cast<AtomicType>(-1);
 176
 177   AtomicType value;
 178
 179   base::subtle::NoBarrier_Store(&value, kVal1);
 180   EXPECT_EQ(kVal1, value);
 181   base::subtle::NoBarrier_Store(&value, kVal2);
 182   EXPECT_EQ(kVal2, value);
 183
 184   base::subtle::Release_Store(&value, kVal1);
 185   EXPECT_EQ(kVal1, value);
 186   base::subtle::Release_Store(&value, kVal2);
 187   EXPECT_EQ(kVal2, value);
 188 }
 189
 190 // This is a simple sanity check that values are correct. Not testing
 191 // atomicity
 192 template <class AtomicType>
 193 static void TestLoad() {
 194   const AtomicType kVal1 = TestFillValue<AtomicType>();
 195   const AtomicType kVal2 = static_cast<AtomicType>(-1);
 196
 197   AtomicType value;
 198
 199   value = kVal1;
 200   EXPECT_EQ(kVal1, base::subtle::NoBarrier_Load(&value));
 201   value = kVal2;
 202   EXPECT_EQ(kVal2, base::subtle::NoBarrier_Load(&value));
 203
 204   value = kVal1;
 205   EXPECT_EQ(kVal1, base::subtle::Acquire_Load(&value));
 206   value = kVal2;
 207   EXPECT_EQ(kVal2, base::subtle::Acquire_Load(&value));
 208 }
 209
 210 TEST(AtomicOpsTest, Inc) {
 211   TestAtomicIncrement<base::subtle::Atomic32>();
 212   TestAtomicIncrement<base::subtle::AtomicWord>();
 213 }
 214
 215 TEST(AtomicOpsTest, CompareAndSwap) {
 216   TestCompareAndSwap<base::subtle::Atomic32>();
 217   TestCompareAndSwap<base::subtle::AtomicWord>();
 218 }
 219
 220 TEST(AtomicOpsTest, Exchange) {
 221   TestAtomicExchange<base::subtle::Atomic32>();
 222   TestAtomicExchange<base::subtle::AtomicWord>();
 223 }
 224
 225 TEST(AtomicOpsTest, IncrementBounds) {
 226   TestAtomicIncrementBounds<base::subtle::Atomic32>();
 227   TestAtomicIncrementBounds<base::subtle::AtomicWord>();
 228 }
 229
 230 TEST(AtomicOpsTest, Store) {
 231   TestStore<base::subtle::Atomic32>();
 232   TestStore<base::subtle::AtomicWord>();
 233 }
 234
 235 TEST(AtomicOpsTest, Load) {
 236   TestLoad<base::subtle::Atomic32>();
 237   TestLoad<base::subtle::AtomicWord>();
 238 }