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