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llvm-mirror/runtime/libtrace/tracelib.c
Vikram S. Adve 4761eb23fd 1. Make table size prime -- improves hashing performance vastly.
2. Reduce #hashes from 2 to 1 for initial inserts.
3. Fix incorrect assertion from last checkin.

llvm-svn: 7417
2003-07-30 12:49:25 +00:00

393 lines
12 KiB
C

/*===-- tracelib.c - Runtime routines for tracing ---------------*- C++ -*-===*
*
* Runtime routines for supporting tracing of execution for code generated by
* LLVM.
*
*===----------------------------------------------------------------------===*/
#include "tracelib.h"
#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "Support/DataTypes.h"
/*===---------------------------------------------------------------------=====
* HASH FUNCTIONS
*===---------------------------------------------------------------------===*/
/* use #defines until we have inlining */
typedef uintptr_t Index; /* type of keys, size for hash table */
typedef uint32_t Generic; /* type of values stored in table */
/* Index IntegerHashFunc(const Generic value, const Index size) */
#define IntegerHashFunc(value, size) \
( ((((Index) value) << 3) ^ (((Index) value) >> 3)) % size )
/* Index IntegerRehashFunc(const Generic oldHashValue, const Index size) */
#define IntegerRehashFunc(oldHashValue, size) \
((Index) ((oldHashValue+16) % size)) /* 16 is relatively prime to a Mersenne prime! */
/* Index PointerHashFunc(const void* value, const Index size) */
#define PointerHashFunc(value, size) \
IntegerHashFunc((Index) value, size)
/* Index PointerRehashFunc(const void* value, const Index size) */
#define PointerRehashFunc(value, size) \
IntegerRehashFunc((Index) value, size)
/*===---------------------------------------------------------------------=====
* POINTER-TO-GENERIC HASH TABLE.
* These should be moved to a separate location: HashTable.[ch]
*===---------------------------------------------------------------------===*/
typedef enum { FIND, ENTER } ACTION;
typedef char FULLEMPTY;
const FULLEMPTY EMPTY = '\0';
const FULLEMPTY FULL = '\1';
// List of primes closest to powers of 2 in [2^20 -- 2^30], obtained from
// http://www.utm.edu/research/primes/lists/2small/0bit.html.
// Use these as the successive sizes of the hash table.
#define NUMPRIMES 11
#define FIRSTENTRY 2
const uint PRIMES[NUMPRIMES] = { (1<<20)-3, (1<<21)-9, (1<<22)-3, (1<<23)-15,
(1<<24)-3, (1<<25)-39, (1<<26)-5, (1<<27)-39,
(1<<28)-57, (1<<29)-3, (1<<30)-35 };
uint CurrentSizeEntry = FIRSTENTRY;
const uint MAX_NUM_PROBES = 4;
typedef struct PtrValueHashEntry_struct {
void* key;
Generic value;
} PtrValueHashEntry;
typedef struct PtrValueHashTable_struct {
PtrValueHashEntry* table;
FULLEMPTY* fullEmptyFlags;
Index capacity;
Index size;
} PtrValueHashTable;
static Generic LookupOrInsertPtr(PtrValueHashTable* ptrTable, void* ptr,
ACTION action, Generic value);
static void Insert(PtrValueHashTable* ptrTable, void* ptr, Generic value);
static void Delete(PtrValueHashTable* ptrTable, void* ptr);
/* Returns 0 if the item is not found. */
/* void* LookupPtr(PtrValueHashTable* ptrTable, void* ptr) */
#define LookupPtr(ptrTable, ptr) \
LookupOrInsertPtr(ptrTable, ptr, FIND, (Generic) 0)
void
InitializeTable(PtrValueHashTable* ptrTable, Index newSize)
{
ptrTable->table = (PtrValueHashEntry*) calloc(newSize,
sizeof(PtrValueHashEntry));
ptrTable->fullEmptyFlags = (FULLEMPTY*) calloc(newSize, sizeof(FULLEMPTY));
ptrTable->capacity = newSize;
ptrTable->size = 0;
}
PtrValueHashTable*
CreateTable(Index initialSize)
{
PtrValueHashTable* ptrTable =
(PtrValueHashTable*) malloc(sizeof(PtrValueHashTable));
InitializeTable(ptrTable, initialSize);
return ptrTable;
}
void
ReallocTable(PtrValueHashTable* ptrTable, Index newSize)
{
if (newSize <= ptrTable->capacity)
return;
#ifndef NDEBUG
printf("\n***\n*** REALLOCATING SPACE FOR POINTER HASH TABLE.\n");
printf("*** oldSize = %ld, oldCapacity = %ld\n***\n\n",
(long) ptrTable->size, (long) ptrTable->capacity);
#endif
unsigned int i;
PtrValueHashEntry* oldTable = ptrTable->table;
FULLEMPTY* oldFlags = ptrTable->fullEmptyFlags;
Index oldSize = ptrTable->size;
Index oldCapacity = ptrTable->capacity;
/* allocate the new storage and flags and re-insert the old entries */
InitializeTable(ptrTable, newSize);
for (i=0; i < oldCapacity; ++i)
if (oldFlags[i] == FULL)
Insert(ptrTable, oldTable[i].key, oldTable[i].value);
assert(ptrTable->size == oldSize && "Incorrect number of entries copied?");
#ifndef NDEBUG
for (i=0; i < oldCapacity; ++i)
if (oldFlags[i] == FULL)
assert(LookupPtr(ptrTable, oldTable[i].key) == oldTable[i].value);
#endif
free(oldTable);
free(oldFlags);
}
void
DeleteTable(PtrValueHashTable* ptrTable)
{
free(ptrTable->table);
free(ptrTable->fullEmptyFlags);
memset(ptrTable, '\0', sizeof(PtrValueHashTable));
free(ptrTable);
}
void
InsertAtIndex(PtrValueHashTable* ptrTable, void* ptr, Generic value, Index index)
{
assert(ptrTable->fullEmptyFlags[index] == EMPTY && "Slot is in use!");
ptrTable->table[index].key = ptr;
ptrTable->table[index].value = value;
ptrTable->fullEmptyFlags[index] = FULL;
ptrTable->size++;
}
void
DeleteAtIndex(PtrValueHashTable* ptrTable, Index index)
{
assert(ptrTable->fullEmptyFlags[index] == FULL && "Deleting empty slot!");
ptrTable->table[index].key = 0;
ptrTable->table[index].value = (Generic) 0;
ptrTable->fullEmptyFlags[index] = EMPTY;
ptrTable->size--;
}
Index
FindIndex(PtrValueHashTable* ptrTable, void* ptr)
{
uint numProbes = 1;
Index index = PointerHashFunc(ptr, ptrTable->capacity);
if (ptrTable->fullEmptyFlags[index] == FULL)
{
if (ptrTable->table[index].key == ptr)
return index;
/* First lookup failed on non-empty slot: probe further */
while (numProbes < MAX_NUM_PROBES)
{
index = PointerRehashFunc(index, ptrTable->capacity);
if (ptrTable->fullEmptyFlags[index] == EMPTY)
break;
else if (ptrTable->table[index].key == ptr)
return index;
++numProbes;
}
}
/* Lookup failed: item is not in the table. */
/* If last slot is empty, use that slot. */
/* Otherwise, table must have been reallocated, so search again. */
if (numProbes == MAX_NUM_PROBES)
{ /* table is too full: reallocate and search again */
if (CurrentSizeEntry >= NUMPRIMES-1) {
fprintf(stderr, "Out of PRIME Numbers!!!");
abort();
}
ReallocTable(ptrTable, PRIMES[++CurrentSizeEntry]);
return FindIndex(ptrTable, ptr);
}
else
{
assert(ptrTable->fullEmptyFlags[index] == EMPTY &&
"Stopped before finding an empty slot and before MAX probes!");
return index;
}
}
/* Look up hash table using 'ptr' as the key. If an entry exists, return
* the value mapped to 'ptr'. If not, and if action==ENTER is specified,
* create a new entry with value 'value', but return 0 in any case.
*/
Generic
LookupOrInsertPtr(PtrValueHashTable* ptrTable, void* ptr, ACTION action,
Generic value)
{
Index index = FindIndex(ptrTable, ptr);
if (ptrTable->fullEmptyFlags[index] == FULL &&
ptrTable->table[index].key == ptr)
return ptrTable->table[index].value;
/* Lookup failed: item is not in the table */
/* If action is ENTER, insert item into the table. Return 0 in any case. */
if (action == ENTER)
InsertAtIndex(ptrTable, ptr, value, index);
return (Generic) 0;
}
void
Insert(PtrValueHashTable* ptrTable, void* ptr, Generic value)
{
Index index = FindIndex(ptrTable, ptr);
assert(ptrTable->fullEmptyFlags[index] == EMPTY &&
"ptr is already in the table: delete it first!");
InsertAtIndex(ptrTable, ptr, value, index);
}
void
Delete(PtrValueHashTable* ptrTable, void* ptr)
{
Index index = FindIndex(ptrTable, ptr);
if (ptrTable->fullEmptyFlags[index] == FULL &&
ptrTable->table[index].key == ptr)
{
DeleteAtIndex(ptrTable, index);
}
}
/*===---------------------------------------------------------------------=====
* RUNTIME ROUTINES TO MAP POINTERS TO SEQUENCE NUMBERS
*===---------------------------------------------------------------------===*/
PtrValueHashTable* SequenceNumberTable = NULL;
#define INITIAL_SIZE (PRIMES[FIRSTENTRY])
#define MAX_NUM_SAVED 1024
typedef struct PointerSet_struct {
char* savedPointers[MAX_NUM_SAVED]; /* 1024 alloca'd ptrs shd suffice */
unsigned int numSaved;
struct PointerSet_struct* nextOnStack; /* implement a cheap stack */
} PointerSet;
PointerSet* topOfStack = NULL;
SequenceNumber
HashPointerToSeqNum(char* ptr)
{
static SequenceNumber count = 0;
SequenceNumber seqnum;
if (SequenceNumberTable == NULL) {
assert(MAX_NUM_PROBES < INITIAL_SIZE+1 && "Initial size too small");
SequenceNumberTable = CreateTable(INITIAL_SIZE);
}
seqnum = (SequenceNumber)
LookupOrInsertPtr(SequenceNumberTable, ptr, ENTER, count+1);
if (seqnum == 0) /* new entry was created with value count+1 */
seqnum = ++count; /* so increment counter */
assert(seqnum <= count && "Invalid sequence number in table!");
return seqnum;
}
void
ReleasePointerSeqNum(char* ptr)
{ /* if a sequence number was assigned to this ptr, release it */
if (SequenceNumberTable != NULL)
Delete(SequenceNumberTable, ptr);
}
void
PushPointerSet()
{
PointerSet* newSet = (PointerSet*) malloc(sizeof(PointerSet));
newSet->numSaved = 0;
newSet->nextOnStack = topOfStack;
topOfStack = newSet;
}
void
PopPointerSet()
{
PointerSet* oldSet;
assert(topOfStack != NULL && "popping from empty stack!");
oldSet = topOfStack;
topOfStack = oldSet->nextOnStack;
assert(oldSet->numSaved == 0);
free(oldSet);
}
/* free the pointers! */
static void
ReleaseRecordedPointers(char* savedPointers[MAX_NUM_SAVED],
unsigned int numSaved)
{
unsigned int i;
for (i=0; i < topOfStack->numSaved; ++i)
ReleasePointerSeqNum(topOfStack->savedPointers[i]);
}
void
ReleasePointersPopSet()
{
ReleaseRecordedPointers(topOfStack->savedPointers, topOfStack->numSaved);
topOfStack->numSaved = 0;
PopPointerSet();
}
void
RecordPointer(char* ptr)
{ /* record pointers for release later */
if (topOfStack->numSaved == MAX_NUM_SAVED) {
printf("***\n*** WARNING: OUT OF ROOM FOR SAVED POINTERS."
" ALL POINTERS ARE BEING FREED.\n"
"*** THE SEQUENCE NUMBERS OF SAVED POINTERS WILL CHANGE!\n*** \n");
ReleaseRecordedPointers(topOfStack->savedPointers, topOfStack->numSaved);
topOfStack->numSaved = 0;
}
topOfStack->savedPointers[topOfStack->numSaved++] = ptr;
}
/*===---------------------------------------------------------------------=====
* TEST DRIVER FOR INSTRUMENTATION LIBRARY
*===---------------------------------------------------------------------===*/
#ifndef TEST_INSTRLIB
#undef TEST_INSTRLIB /* #define this to turn on by default */
#endif
#ifdef TEST_INSTRLIB
int
main(int argc, char** argv)
{
int i, j;
int doRelease = 0;
INITIAL_SIZE = 5; /* start with small table to test realloc's*/
if (argc > 1 && ! strcmp(argv[1], "-r"))
{
PushPointerSet();
doRelease = 1;
}
for (i=0; i < argc; ++i)
for (j=0; argv[i][j]; ++j)
{
printf("Sequence number for argc[%d][%d] (%c) = Hash(%p) = %d\n",
i, j, argv[i][j], argv[i]+j, HashPointerToSeqNum(argv[i]+j));
if (doRelease)
RecordPointer(argv[i]+j);
}
if (doRelease)
ReleasePointersPopSet();
/* print sequence numbers out again to compare with (-r) and w/o release */
for (i=argc-1; i >= 0; --i)
for (j=0; argv[i][j]; ++j)
printf("Sequence number for argc[%d][%d] (%c) = %d\n",
i, j, argv[i][j], argv[i]+j, HashPointerToSeqNum(argv[i]+j));
return 0;
}
#endif