Avoid seg fault in the case where ensureModel is called in cds_func_entry and then...
[c11tester.git] / datarace.cc
index 1cc407bb991889545210f54ec313ae84c49cf412..dd88c2fe98f095d678e55c3dbf1162d98298b9d7 100644 (file)
 #include "datarace.h"
 #include "model.h"
-#include "threads.h"
+#include "threads-model.h"
 #include <stdio.h>
 #include <cstring>
-
-struct ShadowTable *root;
-std::vector<struct DataRace *> unrealizedraces;
+#include "mymemory.h"
+#include "clockvector.h"
+#include "config.h"
+#include "action.h"
+#include "execution.h"
+#include "stl-model.h"
+#include <execinfo.h>
+
+static struct ShadowTable *root;
+static void *memory_base;
+static void *memory_top;
+static RaceSet * raceset;
+
+static const ModelExecution * get_execution()
+{
+       return model->get_execution();
+}
 
 /** This function initialized the data race detector. */
-void initRaceDetector() {
-       root=(struct ShadowTable *) calloc(sizeof(struct ShadowTable),1);
+void initRaceDetector()
+{
+       root = (struct ShadowTable *)snapshot_calloc(sizeof(struct ShadowTable), 1);
+       memory_base = snapshot_calloc(sizeof(struct ShadowBaseTable) * SHADOWBASETABLES, 1);
+       memory_top = ((char *)memory_base) + sizeof(struct ShadowBaseTable) * SHADOWBASETABLES;
+       raceset = new RaceSet();
+}
+
+void * table_calloc(size_t size)
+{
+       if ((((char *)memory_base) + size) > memory_top) {
+               return snapshot_calloc(size, 1);
+       } else {
+               void *tmp = memory_base;
+               memory_base = ((char *)memory_base) + size;
+               return tmp;
+       }
 }
 
 /** This function looks up the entry in the shadow table corresponding to a
  * given address.*/
-static uint64_t * lookupAddressEntry(void * address) {
-       struct ShadowTable *currtable=root;
+static uint64_t * lookupAddressEntry(const void *address)
+{
+       struct ShadowTable *currtable = root;
 #if BIT48
-       currtable=(struct ShadowTable *) currtable->array[(((uintptr_t)address)>>32)&MASK16BIT];
-       if (currtable==NULL) {
-               currtable=(struct ShadowTable *) (root->array[(((uintptr_t)address)>>32)&MASK16BIT]=calloc(sizeof(struct ShadowTable),1));
+       currtable = (struct ShadowTable *) currtable->array[(((uintptr_t)address) >> 32) & MASK16BIT];
+       if (currtable == NULL) {
+               currtable = (struct ShadowTable *)(root->array[(((uintptr_t)address) >> 32) & MASK16BIT] = table_calloc(sizeof(struct ShadowTable)));
        }
 #endif
 
-       struct ShadowBaseTable * basetable=(struct ShadowBaseTable *) currtable->array[(((uintptr_t)address)>>16)&MASK16BIT];
-       if (basetable==NULL) {
-               basetable=(struct ShadowBaseTable *) (currtable->array[(((uintptr_t)address)>>16)&MASK16BIT]=calloc(sizeof(struct ShadowBaseTable),1));
+       struct ShadowBaseTable *basetable = (struct ShadowBaseTable *)currtable->array[(((uintptr_t)address) >> 16) & MASK16BIT];
+       if (basetable == NULL) {
+               basetable = (struct ShadowBaseTable *)(currtable->array[(((uintptr_t)address) >> 16) & MASK16BIT] = table_calloc(sizeof(struct ShadowBaseTable)));
+       }
+       return &basetable->array[((uintptr_t)address) & MASK16BIT];
+}
+
+
+bool hasNonAtomicStore(const void *address) {
+       uint64_t * shadow = lookupAddressEntry(address);
+       uint64_t shadowval = *shadow;
+       if (ISSHORTRECORD(shadowval)) {
+               //Do we have a non atomic write with a non-zero clock
+               return ((WRITEVECTOR(shadowval) != 0) && !(ATOMICMASK & shadowval));
+       } else {
+               if (shadowval == 0)
+                       return false;
+               struct RaceRecord *record = (struct RaceRecord *)shadowval;
+               return !record->isAtomic && record->writeClock != 0;
+       }
+}
+
+void setAtomicStoreFlag(const void *address) {
+       uint64_t * shadow = lookupAddressEntry(address);
+       uint64_t shadowval = *shadow;
+       if (ISSHORTRECORD(shadowval)) {
+               *shadow = shadowval | ATOMICMASK;
+       } else {
+               if (shadowval == 0)
+                       return;
+               struct RaceRecord *record = (struct RaceRecord *)shadowval;
+               record->isAtomic = 1;
+       }
+}
+
+void getStoreThreadAndClock(const void *address, thread_id_t * thread, modelclock_t * clock) {
+       uint64_t * shadow = lookupAddressEntry(address);
+       uint64_t shadowval = *shadow;
+       if (ISSHORTRECORD(shadowval)) {
+               //Do we have a non atomic write with a non-zero clock
+               *thread = WRTHREADID(shadowval);
+               *clock = WRITEVECTOR(shadowval);
+       } else {
+               struct RaceRecord *record = (struct RaceRecord *)shadowval;
+               *thread = record->writeThread;
+               *clock = record->writeClock;
        }
-       return &basetable->array[((uintptr_t)address)&MASK16BIT];
 }
 
 /**
@@ -40,7 +112,7 @@ static uint64_t * lookupAddressEntry(void * address) {
  * @return true if the current clock allows a race with the event at clock2/tid2
  */
 static bool clock_may_race(ClockVector *clock1, thread_id_t tid1,
-                           modelclock_t clock2, thread_id_t tid2)
+                                                                                                        modelclock_t clock2, thread_id_t tid2)
 {
        return tid1 != tid2 && clock2 != 0 && clock1->getClock(tid2) <= clock2;
 }
@@ -49,125 +121,221 @@ static bool clock_may_race(ClockVector *clock1, thread_id_t tid1,
  * Expands a record from the compact form to the full form.  This is
  * necessary for multiple readers or for very large thread ids or time
  * stamps. */
-static void expandRecord(uint64_t * shadow) {
-       uint64_t shadowval=*shadow;
+static void expandRecord(uint64_t *shadow)
+{
+       uint64_t shadowval = *shadow;
 
        modelclock_t readClock = READVECTOR(shadowval);
        thread_id_t readThread = int_to_id(RDTHREADID(shadowval));
        modelclock_t writeClock = WRITEVECTOR(shadowval);
        thread_id_t writeThread = int_to_id(WRTHREADID(shadowval));
 
-       struct RaceRecord * record=(struct RaceRecord *)calloc(1,sizeof(struct RaceRecord));
-       record->writeThread=writeThread;
-       record->writeClock=writeClock;
-
-       if (readClock!=0) {
-               record->capacity=INITCAPACITY;
-               record->thread=(thread_id_t *) malloc(sizeof(thread_id_t)*record->capacity);
-               record->readClock=(modelclock_t *) malloc(sizeof(modelclock_t)*record->capacity);
-               record->numReads=1;
-               record->thread[0]=readThread;
-               record->readClock[0]=readClock;
+       struct RaceRecord *record = (struct RaceRecord *)snapshot_calloc(1, sizeof(struct RaceRecord));
+       record->writeThread = writeThread;
+       record->writeClock = writeClock;
+
+       if (readClock != 0) {
+               record->thread = (thread_id_t *)snapshot_malloc(sizeof(thread_id_t) * INITCAPACITY);
+               record->readClock = (modelclock_t *)snapshot_malloc(sizeof(modelclock_t) * INITCAPACITY);
+               record->numReads = 1;
+               ASSERT(readThread >= 0);
+               record->thread[0] = readThread;
+               record->readClock[0] = readClock;
        }
-       *shadow=(uint64_t) record;
+       if (shadowval & ATOMICMASK)
+               record->isAtomic = 1;
+       *shadow = (uint64_t) record;
 }
 
-/** This function is called when we detect a data race.*/
-static void reportDataRace(thread_id_t oldthread, modelclock_t oldclock, bool isoldwrite, ModelAction *newaction, bool isnewwrite, void *address) {
-       struct DataRace * race=(struct DataRace *)malloc(sizeof(struct DataRace));
-       race->oldthread=oldthread;
-       race->oldclock=oldclock;
-       race->isoldwrite=isoldwrite;
-       race->newaction=newaction;
-       race->isnewwrite=isnewwrite;
-       race->address=address;
-       unrealizedraces.push_back(race);
-
-       /* If the race is realized, bail out now. */
-       if (checkDataRaces()) {
-               model->set_assert();
-               model->switch_to_master(NULL);
+#define FIRST_STACK_FRAME 2
+
+unsigned int race_hash(struct DataRace *race) {
+       unsigned int hash = 0;
+       for(int i=FIRST_STACK_FRAME;i < race->numframes;i++) {
+               hash ^= ((uintptr_t)race->backtrace[i]);
+               hash = (hash >> 3) | (hash << 29);
        }
+       return hash;
 }
 
-/** This function goes through the list of unrealized data races,
- *     removes the impossible ones, and print the realized ones. */
-
-bool checkDataRaces() {
-       if (model->isfeasibleprefix()) {
-               /* Prune the non-racing unrealized dataraces */
-               unsigned int i,newloc=0;
-               for(i=0;i<unrealizedraces.size();i++) {
-                       struct DataRace * race=unrealizedraces[i];
-                       if (clock_may_race(race->newaction->get_cv(), race->newaction->get_tid(), race->oldclock, race->oldthread)) {
-                               unrealizedraces[newloc++]=race;
-                       }
-               }
-               if (newloc!=i)
-                       unrealizedraces.resize(newloc);
-
-               if (unrealizedraces.size()!=0) {
-                       /* We have an actual realized race. */
-                       for(i=0;i<unrealizedraces.size();i++) {
-                               struct DataRace * race=unrealizedraces[i];
-                               printRace(race);
-                       }
-                       return true;
-               }
+
+bool race_equals(struct DataRace *r1, struct DataRace *r2) {
+       if (r1->numframes != r2->numframes)
+               return false;
+       for(int i=FIRST_STACK_FRAME;i < r1->numframes;i++) {
+               if (r1->backtrace[i] != r2->backtrace[i])
+                       return false;
        }
-       return false;
+       return true;
+}
+
+/** This function is called when we detect a data race.*/
+static struct DataRace * reportDataRace(thread_id_t oldthread, modelclock_t oldclock, bool isoldwrite, ModelAction *newaction, bool isnewwrite, const void *address)
+{
+       struct DataRace *race = (struct DataRace *)model_malloc(sizeof(struct DataRace));
+       race->oldthread = oldthread;
+       race->oldclock = oldclock;
+       race->isoldwrite = isoldwrite;
+       race->newaction = newaction;
+       race->isnewwrite = isnewwrite;
+       race->address = address;
+       return race;
 }
 
-void printRace(struct DataRace * race) {
-       printf("Datarace detected\n");
-       printf("Location %p\n", race->address);
-       printf("Initial access: thread %u clock %u, iswrite %u\n",race->oldthread,race->oldclock, race->isoldwrite);
-       printf("Second access: thread %u clock %u, iswrite %u\n", race->newaction->get_tid(), race->newaction->get_seq_number() , race->isnewwrite);
+/**
+ * @brief Assert a data race
+ *
+ * Asserts a data race which is currently realized, causing the execution to
+ * end and stashing a message in the model-checker's bug list
+ *
+ * @param race The race to report
+ */
+void assert_race(struct DataRace *race)
+{
+       model_print("Race detected at location: \n");
+       backtrace_symbols_fd(race->backtrace, race->numframes, model_out);
+       model_print("\nData race detected @ address %p:\n"
+                                                       "    Access 1: %5s in thread %2d @ clock %3u\n"
+                                                       "    Access 2: %5s in thread %2d @ clock %3u\n\n",
+                                                       race->address,
+                                                       race->isoldwrite ? "write" : "read",
+                                                       id_to_int(race->oldthread),
+                                                       race->oldclock,
+                                                       race->isnewwrite ? "write" : "read",
+                                                       id_to_int(race->newaction->get_tid()),
+                                                       race->newaction->get_seq_number()
+                                                       );
 }
 
 /** This function does race detection for a write on an expanded record. */
-void fullRaceCheckWrite(thread_id_t thread, void *location, uint64_t * shadow, ClockVector *currClock) {
-       struct RaceRecord * record=(struct RaceRecord *) (*shadow);
+struct DataRace * fullRaceCheckWrite(thread_id_t thread, void *location, uint64_t *shadow, ClockVector *currClock)
+{
+       struct RaceRecord *record = (struct RaceRecord *)(*shadow);
+       struct DataRace * race = NULL;
 
        /* Check for datarace against last read. */
 
-       for(int i=0;i<record->numReads;i++) {
+       for (int i = 0;i < record->numReads;i++) {
                modelclock_t readClock = record->readClock[i];
                thread_id_t readThread = record->thread[i];
 
                /* Note that readClock can't actuall be zero here, so it could be
-                        optimized. */
+                        optimized. */
 
                if (clock_may_race(currClock, thread, readClock, readThread)) {
                        /* We have a datarace */
-                       reportDataRace(readThread, readClock, false, model->get_parent_action(thread), true, location);
+                       race = reportDataRace(readThread, readClock, false, get_execution()->get_parent_action(thread), true, location);
+                       goto Exit;
                }
        }
 
        /* Check for datarace against last write. */
 
-       modelclock_t writeClock = record->writeClock;
-       thread_id_t writeThread = record->writeThread;
+       {
+               modelclock_t writeClock = record->writeClock;
+               thread_id_t writeThread = record->writeThread;
 
-       if (clock_may_race(currClock, thread, writeClock, writeThread)) {
-               /* We have a datarace */
-               reportDataRace(writeThread, writeClock, true, model->get_parent_action(thread), true, location);
+               if (clock_may_race(currClock, thread, writeClock, writeThread)) {
+                       /* We have a datarace */
+                       race = reportDataRace(writeThread, writeClock, true, get_execution()->get_parent_action(thread), true, location);
+                       goto Exit;
+               }
        }
-
-       record->numReads=0;
-       record->writeThread=thread;
+Exit:
+       record->numReads = 0;
+       record->writeThread = thread;
+       record->isAtomic = 0;
        modelclock_t ourClock = currClock->getClock(thread);
-       record->writeClock=ourClock;
+       record->writeClock = ourClock;
+       return race;
 }
 
 /** This function does race detection on a write. */
-void raceCheckWrite(thread_id_t thread, void *location, ClockVector *currClock) {
-       uint64_t * shadow=lookupAddressEntry(location);
-       uint64_t shadowval=*shadow;
+void raceCheckWrite(thread_id_t thread, void *location)
+{
+       uint64_t *shadow = lookupAddressEntry(location);
+       uint64_t shadowval = *shadow;
+       ClockVector *currClock = get_execution()->get_cv(thread);
+       if (currClock == NULL)
+               return;
 
+       struct DataRace * race = NULL;
        /* Do full record */
-       if (shadowval!=0&&!ISSHORTRECORD(shadowval)) {
-               fullRaceCheckWrite(thread, location, shadow, currClock);
+       if (shadowval != 0 && !ISSHORTRECORD(shadowval)) {
+               race = fullRaceCheckWrite(thread, location, shadow, currClock);
+               goto Exit;
+       }
+
+       {
+               int threadid = id_to_int(thread);
+               modelclock_t ourClock = currClock->getClock(thread);
+
+               /* Thread ID is too large or clock is too large. */
+               if (threadid > MAXTHREADID || ourClock > MAXWRITEVECTOR) {
+                       expandRecord(shadow);
+                       race = fullRaceCheckWrite(thread, location, shadow, currClock);
+                       goto Exit;
+               }
+
+
+
+               {
+                       /* Check for datarace against last read. */
+
+                       modelclock_t readClock = READVECTOR(shadowval);
+                       thread_id_t readThread = int_to_id(RDTHREADID(shadowval));
+
+                       if (clock_may_race(currClock, thread, readClock, readThread)) {
+                               /* We have a datarace */
+                               race = reportDataRace(readThread, readClock, false, get_execution()->get_parent_action(thread), true, location);
+                               goto ShadowExit;
+                       }
+               }
+
+               {
+                       /* Check for datarace against last write. */
+
+                       modelclock_t writeClock = WRITEVECTOR(shadowval);
+                       thread_id_t writeThread = int_to_id(WRTHREADID(shadowval));
+
+                       if (clock_may_race(currClock, thread, writeClock, writeThread)) {
+                               /* We have a datarace */
+                               race = reportDataRace(writeThread, writeClock, true, get_execution()->get_parent_action(thread), true, location);
+                               goto ShadowExit;
+                       }
+               }
+
+ShadowExit:
+               *shadow = ENCODEOP(0, 0, threadid, ourClock);
+       }
+
+Exit:
+       if (race) {
+               race->numframes=backtrace(race->backtrace, sizeof(race->backtrace)/sizeof(void*));
+               if (raceset->add(race))
+                       assert_race(race);
+               else model_free(race);
+       }
+}
+
+/** This function does race detection for a write on an expanded record. */
+void fullRecordWrite(thread_id_t thread, void *location, uint64_t *shadow, ClockVector *currClock) {
+       struct RaceRecord *record = (struct RaceRecord *)(*shadow);
+       record->numReads = 0;
+       record->writeThread = thread;
+       modelclock_t ourClock = currClock->getClock(thread);
+       record->writeClock = ourClock;
+       record->isAtomic = 1;
+}
+
+/** This function just updates metadata on atomic write. */
+void recordWrite(thread_id_t thread, void *location) {
+       uint64_t *shadow = lookupAddressEntry(location);
+       uint64_t shadowval = *shadow;
+       ClockVector *currClock = get_execution()->get_cv(thread);
+       /* Do full record */
+       if (shadowval != 0 && !ISSHORTRECORD(shadowval)) {
+               fullRecordWrite(thread, location, shadow, currClock);
                return;
        }
 
@@ -177,36 +345,20 @@ void raceCheckWrite(thread_id_t thread, void *location, ClockVector *currClock)
        /* Thread ID is too large or clock is too large. */
        if (threadid > MAXTHREADID || ourClock > MAXWRITEVECTOR) {
                expandRecord(shadow);
-               fullRaceCheckWrite(thread, location, shadow, currClock);
+               fullRecordWrite(thread, location, shadow, currClock);
                return;
        }
 
-       /* Check for datarace against last read. */
-
-       modelclock_t readClock = READVECTOR(shadowval);
-       thread_id_t readThread = int_to_id(RDTHREADID(shadowval));
-
-       if (clock_may_race(currClock, thread, readClock, readThread)) {
-               /* We have a datarace */
-               reportDataRace(readThread, readClock, false, model->get_parent_action(thread), true, location);
-       }
-
-       /* Check for datarace against last write. */
+       *shadow = ENCODEOP(0, 0, threadid, ourClock) | ATOMICMASK;
+}
 
-       modelclock_t writeClock = WRITEVECTOR(shadowval);
-       thread_id_t writeThread = int_to_id(WRTHREADID(shadowval));
 
-       if (clock_may_race(currClock, thread, writeClock, writeThread)) {
-               /* We have a datarace */
-               reportDataRace(writeThread, writeClock, true, model->get_parent_action(thread), true, location);
-       }
-       *shadow = ENCODEOP(0, 0, threadid, ourClock);
-}
 
 /** This function does race detection on a read for an expanded record. */
-void fullRaceCheckRead(thread_id_t thread, void *location, uint64_t * shadow, ClockVector *currClock) {
-       struct RaceRecord * record=(struct RaceRecord *) (*shadow);
-
+struct DataRace * fullRaceCheckRead(thread_id_t thread, const void *location, uint64_t *shadow, ClockVector *currClock)
+{
+       struct RaceRecord *record = (struct RaceRecord *) (*shadow);
+       struct DataRace * race = NULL;
        /* Check for datarace against last write. */
 
        modelclock_t writeClock = record->writeClock;
@@ -214,93 +366,120 @@ void fullRaceCheckRead(thread_id_t thread, void *location, uint64_t * shadow, Cl
 
        if (clock_may_race(currClock, thread, writeClock, writeThread)) {
                /* We have a datarace */
-               reportDataRace(writeThread, writeClock, true, model->get_parent_action(thread), false, location);
+               race = reportDataRace(writeThread, writeClock, true, get_execution()->get_parent_action(thread), false, location);
        }
 
        /* Shorten vector when possible */
 
-       int copytoindex=0;
+       int copytoindex = 0;
 
-       for(int i=0;i<record->numReads;i++) {
+       for (int i = 0;i < record->numReads;i++) {
                modelclock_t readClock = record->readClock[i];
                thread_id_t readThread = record->thread[i];
 
-               /*  Note that is not really a datarace check as reads cannott
-                               actually race.  It is just determining that this read subsumes
-                               another in the sense that either this read races or neither
-                               read races. Note that readClock can't actually be zero, so it
-                               could be optimized.  */
+               /*  Note that is not really a datarace check as reads cannot
+                               actually race.  It is just determining that this read subsumes
+                               another in the sense that either this read races or neither
+                               read races. Note that readClock can't actually be zero, so it
+                               could be optimized.  */
 
                if (clock_may_race(currClock, thread, readClock, readThread)) {
                        /* Still need this read in vector */
-                       if (copytoindex!=i) {
-                               record->readClock[copytoindex]=record->readClock[i];
-                               record->thread[copytoindex]=record->thread[i];
+                       if (copytoindex != i) {
+                               ASSERT(record->thread[i] >= 0);
+                               record->readClock[copytoindex] = record->readClock[i];
+                               record->thread[copytoindex] = record->thread[i];
                        }
                        copytoindex++;
                }
        }
 
-       if (copytoindex>=record->capacity) {
-               int newCapacity=record->capacity*2;
-               thread_id_t *newthread=(thread_id_t *) malloc(sizeof(thread_id_t)*newCapacity);
-               modelclock_t * newreadClock=(modelclock_t *) malloc(sizeof(modelclock_t)*newCapacity);
-               std::memcpy(newthread, record->thread, record->capacity*sizeof(thread_id_t));
-               std::memcpy(newreadClock, record->readClock, record->capacity*sizeof(modelclock_t));
-               free(record->readClock);
-               free(record->thread);
-               record->readClock=newreadClock;
-               record->thread=newthread;
-               record->capacity=newCapacity;
+       if (__builtin_popcount(copytoindex) <= 1) {
+               if (copytoindex == 0) {
+                       int newCapacity = INITCAPACITY;
+                       record->thread = (thread_id_t *)snapshot_malloc(sizeof(thread_id_t) * newCapacity);
+                       record->readClock = (modelclock_t *)snapshot_malloc(sizeof(modelclock_t) * newCapacity);
+               } else if (copytoindex>=INITCAPACITY) {
+                       int newCapacity = copytoindex * 2;
+                       thread_id_t *newthread = (thread_id_t *)snapshot_malloc(sizeof(thread_id_t) * newCapacity);
+                       modelclock_t *newreadClock = (modelclock_t *)snapshot_malloc(sizeof(modelclock_t) * newCapacity);
+                       std::memcpy(newthread, record->thread, copytoindex * sizeof(thread_id_t));
+                       std::memcpy(newreadClock, record->readClock, copytoindex * sizeof(modelclock_t));
+                       snapshot_free(record->readClock);
+                       snapshot_free(record->thread);
+                       record->readClock = newreadClock;
+                       record->thread = newthread;
+               }
        }
 
        modelclock_t ourClock = currClock->getClock(thread);
 
-       record->thread[copytoindex]=thread;
-       record->readClock[copytoindex]=ourClock;
-       record->numReads=copytoindex+1;
+       ASSERT(thread >= 0);
+       record->thread[copytoindex] = thread;
+       record->readClock[copytoindex] = ourClock;
+       record->numReads = copytoindex + 1;
+       return race;
 }
 
 /** This function does race detection on a read. */
-void raceCheckRead(thread_id_t thread, void *location, ClockVector *currClock) {
-       uint64_t * shadow=lookupAddressEntry(location);
-       uint64_t shadowval=*shadow;
+void raceCheckRead(thread_id_t thread, const void *location)
+{
+       uint64_t *shadow = lookupAddressEntry(location);
+       uint64_t shadowval = *shadow;
+       ClockVector *currClock = get_execution()->get_cv(thread);
+       if (currClock == NULL)
+               return;
+
+       struct DataRace * race = NULL;
 
        /* Do full record */
-       if (shadowval!=0&&!ISSHORTRECORD(shadowval)) {
-               fullRaceCheckRead(thread, location, shadow, currClock);
-               return;
+       if (shadowval != 0 && !ISSHORTRECORD(shadowval)) {
+               race = fullRaceCheckRead(thread, location, shadow, currClock);
+               goto Exit;
        }
 
-       int threadid = id_to_int(thread);
-       modelclock_t ourClock = currClock->getClock(thread);
+       {
+               int threadid = id_to_int(thread);
+               modelclock_t ourClock = currClock->getClock(thread);
 
-       /* Thread ID is too large or clock is too large. */
-       if (threadid > MAXTHREADID || ourClock > MAXWRITEVECTOR) {
-               expandRecord(shadow);
-               fullRaceCheckRead(thread, location, shadow, currClock);
-               return;
-       }
+               /* Thread ID is too large or clock is too large. */
+               if (threadid > MAXTHREADID || ourClock > MAXWRITEVECTOR) {
+                       expandRecord(shadow);
+                       race = fullRaceCheckRead(thread, location, shadow, currClock);
+                       goto Exit;
+               }
 
-       /* Check for datarace against last write. */
+               /* Check for datarace against last write. */
 
-       modelclock_t writeClock = WRITEVECTOR(shadowval);
-       thread_id_t writeThread = int_to_id(WRTHREADID(shadowval));
+               modelclock_t writeClock = WRITEVECTOR(shadowval);
+               thread_id_t writeThread = int_to_id(WRTHREADID(shadowval));
 
-       if (clock_may_race(currClock, thread, writeClock, writeThread)) {
-               /* We have a datarace */
-               reportDataRace(writeThread, writeClock, true, model->get_parent_action(thread), false, location);
-       }
+               if (clock_may_race(currClock, thread, writeClock, writeThread)) {
+                       /* We have a datarace */
+                       race = reportDataRace(writeThread, writeClock, true, get_execution()->get_parent_action(thread), false, location);
+                       goto ShadowExit;
+               }
 
-       modelclock_t readClock = READVECTOR(shadowval);
-       thread_id_t readThread = int_to_id(RDTHREADID(shadowval));
+ShadowExit:
+               {
+                       modelclock_t readClock = READVECTOR(shadowval);
+                       thread_id_t readThread = int_to_id(RDTHREADID(shadowval));
 
-       if (clock_may_race(currClock, thread, readClock, readThread)) {
-               /* We don't subsume this read... Have to expand record. */
-               expandRecord(shadow);
-               fullRaceCheckRead(thread, location, shadow, currClock);
-               return;
-       }
+                       if (clock_may_race(currClock, thread, readClock, readThread)) {
+                               /* We don't subsume this read... Have to expand record. */
+                               expandRecord(shadow);
+                               fullRaceCheckRead(thread, location, shadow, currClock);
+                               goto Exit;
+                       }
+               }
 
-       *shadow = ENCODEOP(threadid, ourClock, id_to_int(writeThread), writeClock);
+               *shadow = ENCODEOP(threadid, ourClock, id_to_int(writeThread), writeClock) | (shadowval & ATOMICMASK);
+       }
+Exit:
+       if (race) {
+               race->numframes=backtrace(race->backtrace, sizeof(race->backtrace)/sizeof(void*));
+               if (raceset->add(race))
+                       assert_race(race);
+               else model_free(race);
+       }
 }