benchmark/chase-lev-deque-bugfix/deque.c

   1 #include <stdatomic.h>
   2 #include <inttypes.h>
   3 #include "deque.h"
   4 #include <stdlib.h>
   5 #include <stdio.h>
   6
   7 inline bool fail(int ret) {
   8         return ret == ABORT || ret == EMPTY;
   9 }
  10
  11 Deque * create() {
  12         Deque * q = (Deque *) calloc(1, sizeof(Deque));
  13         Array * a = (Array *) calloc(1, sizeof(Array)+2*sizeof(atomic_int));
  14         atomic_store_explicit(&q->array, a, memory_order_relaxed);
  15         atomic_store_explicit(&q->top, 0, memory_order_relaxed);
  16         atomic_store_explicit(&q->bottom, 0, memory_order_relaxed);
  17         atomic_store_explicit(&a->size, 2, memory_order_relaxed);
  18         return q;
  19 }
  20
  21
  22 /**
  23         @Begin
  24         @Interface_define: Take
  25         @End
  26 */
  27 int take(Deque *q) {
  28         size_t b = atomic_load_explicit(&q->bottom, memory_order_relaxed) - 1;
  29         /**
  30                 @Begin
  31                 @Commit_point_define_check: true
  32                 @Label: TakeReadBottom
  33                 @End
  34         */
  35         Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
  36         atomic_store_explicit(&q->bottom, b, memory_order_relaxed);
  37         /**** SPEC (sequential) (testcase1.c) ****/
  38         atomic_thread_fence(memory_order_seq_cst);
  39         size_t t = atomic_load_explicit(&q->top, memory_order_relaxed);
  40         int x;
  41         if (t <= b) {
  42                 /**
  43                         @Begin
  44                         @Commit_point_clear: true
  45                         @Label: TakeClear1
  46                         @End
  47                 */
  48
  49                 /* Non-empty queue. */
  50                 int size = atomic_load_explicit(&a->size,memory_order_relaxed);
  51                 x = atomic_load_explicit(&a->buffer[b % size], memory_order_relaxed);
  52                 /**
  53                         @Begin
  54                         @Commit_point_define_check: true
  55                         @Label: TakeReadBuffer
  56                         @End
  57                 */
  58                 if (t == b) {
  59                         /* Single last element in queue. */
  60                         //FIXME: weaken the following seq_cst causes no spec problem
  61                         bool succ = atomic_compare_exchange_strong_explicit(&q->top, &t, t +
  62                                 1, memory_order_seq_cst, memory_order_relaxed);
  63                         if (!succ) {
  64                                 /**
  65                                         @Begin
  66                                         @Commit_point_clear: true
  67                                         @Label: TakeClear2
  68                                         @End
  69                                 */
  70
  71                                 /**
  72                                         @Begin
  73                                         @Commit_point_define_check: true
  74                                         @Label: TakeReadTop
  75                                         @End
  76                                 */
  77
  78                                 /* Failed race. */
  79                                 x = EMPTY;
  80                         }
  81                         atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
  82                 }
  83         } else { /* Empty queue. */
  84                 x = EMPTY;
  85                 atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
  86         }
  87         return x;
  88 }
  89
  90 void resize(Deque *q) {
  91         Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
  92         size_t size=atomic_load_explicit(&a->size, memory_order_relaxed);
  93         size_t new_size=size << 1;
  94         Array *new_a = (Array *) calloc(1, new_size * sizeof(atomic_int) + sizeof(Array));
  95         size_t top=atomic_load_explicit(&q->top, memory_order_relaxed);
  96         size_t bottom=atomic_load_explicit(&q->bottom, memory_order_relaxed);
  97         atomic_store_explicit(&new_a->size, new_size, memory_order_relaxed);
  98         size_t i;
  99
 100         // Initialize the whole new array to turn off the CDSChecker UL error
 101         // Check if CDSSpec checker can catch this bug
 102         /*
 103         for(i=0; i < new_size; i++) {
 104                 atomic_store_explicit(&new_a->buffer[i % new_size], atomic_load_explicit(&a->buffer[i % size], memory_order_relaxed), memory_order_relaxed);
 105         }
 106         */
 107         for(i=top; i < bottom; i++) {
 108                 atomic_store_explicit(&new_a->buffer[i % new_size], atomic_load_explicit(&a->buffer[i % size], memory_order_relaxed), memory_order_relaxed);
 109         }
 110         /**** detected UL ****/
 111         atomic_store_explicit(&q->array, new_a, memory_order_release);
 112         //printf("resize\n");
 113 }
 114
 115 /**
 116         @Begin
 117         @Interface_define: Push
 118         @End
 119 */
 120 void push(Deque *q, int x) {
 121         size_t b = atomic_load_explicit(&q->bottom, memory_order_relaxed);
 122         /**** SPEC (sequential) ****/
 123         size_t t = atomic_load_explicit(&q->top, memory_order_acquire);
 124         Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
 125         if (b - t > atomic_load_explicit(&a->size, memory_order_relaxed) - 1) /* Full queue. */ {
 126                 resize(q);
 127                 // CDSSpec can actually detect the same bug if we avoid the UL error
 128                 //Bug in paper...should have next line...
 129                 a = (Array *) atomic_load_explicit(&q->array, memory_order_relaxed);
 130         }
 131         int size = atomic_load_explicit(&a->size, memory_order_relaxed);
 132
 133         atomic_store_explicit(&a->buffer[b % size], x, memory_order_relaxed);
 134         /**
 135                 @Begin
 136                 @Commit_point_define_check: true
 137                 @Label: PushUpdateBuffer
 138                 @End
 139         */
 140         /**** UL & SPEC (Sync) (run with -u100 to avoid the uninitialized bug) ****/
 141         atomic_thread_fence(memory_order_release);
 142         atomic_store_explicit(&q->bottom, b + 1, memory_order_relaxed);
 143
 144 }
 145
 146 /**
 147         @Begin
 148         @Interface_define: Steal
 149         @End
 150 */
 151 int steal(Deque *q) {
 152         //Watch out: actually on need to be an acquire (don't count it)
 153         // An old bug
 154         size_t t = atomic_load_explicit(&q->top, memory_order_acquire);
 155         /**
 156                 @Begin
 157                 @Commit_point_define_check: true
 158                 @Label: StealReadTop1
 159                 @End
 160         */
 161         /********** SPEC error (testcase3.c) **********/
 162         atomic_thread_fence(memory_order_seq_cst);
 163         /**** SPEC & UL ****/
 164         size_t b = atomic_load_explicit(&q->bottom, memory_order_acquire);
 165
 166         int x = EMPTY;
 167         if (t < b) {
 168                 /**
 169                         @Begin
 170                         @Commit_point_clear: true
 171                         @Label: StealClear1
 172                         @End
 173                 */
 174
 175                 /* Non-empty queue. */
 176                 /**** detected UL ****/
 177                 Array *a = (Array *) atomic_load_explicit(&q->array, memory_order_acquire);
 178                 int size = atomic_load_explicit(&a->size, memory_order_relaxed);
 179                 x = atomic_load_explicit(&a->buffer[t % size], memory_order_relaxed);
 180                 /**
 181                         @Begin
 182                         @Commit_point_define_check: true
 183                         @Label: StealReadBuffer
 184                         @End
 185                 */
 186                 /**** SPEC (sequential) ****/
 187                 bool succ = atomic_compare_exchange_strong_explicit(&q->top, &t, t + 1,
 188                         memory_order_seq_cst, memory_order_relaxed);
 189                 if (!succ) {
 190                         /**
 191                                 @Begin
 192                                 @Commit_point_clear: true
 193                                 @Label: StealClear2
 194                                 @End
 195                         */
 196
 197                         /**
 198                                 @Begin
 199                                 @Commit_point_define_check: true
 200                                 @Label: StealReadTop2
 201                                 @End
 202                         */
 203
 204                         /* Failed race. */
 205                         return ABORT;
 206                 }
 207         }
 208         return x;
 209 }