/*===-- PathProfiling.c - Support library for path profiling --------------===*\
|*
|* The LLVM Compiler Infrastructure
|*
|* This file is distributed under the University of Illinois Open Source
|* License. See LICENSE.TXT for details.
|*
|*===----------------------------------------------------------------------===*|
|*
|* This file implements the call back routines for the path profiling
|* instrumentation pass. This should be used with the -insert-path-profiling
|* LLVM pass.
|*
\*===----------------------------------------------------------------------===*/
#include "Profiling.h"
#include "llvm/Analysis/ProfileInfoTypes.h"
#include "llvm/Support/DataTypes.h"
#include <sys/types.h>
#if !defined(_MSC_VER) && !defined(__MINGW32__)
#include <unistd.h>
#else
#include <io.h>
#endif
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
/* note that this is used for functions with large path counts,
but it is unlikely those paths will ALL be executed */
#define ARBITRARY_HASH_BIN_COUNT 100
typedef struct pathHashEntry_s {
uint32_t pathNumber;
uint32_t pathCount;
struct pathHashEntry_s* next;
} pathHashEntry_t;
typedef struct pathHashTable_s {
pathHashEntry_t* hashBins[ARBITRARY_HASH_BIN_COUNT];
uint32_t pathCounts;
} pathHashTable_t;
typedef struct {
enum ProfilingStorageType type;
uint32_t size;
void* array;
} ftEntry_t;
/* pointer to the function table allocated in the instrumented program */
ftEntry_t* ft;
uint32_t ftSize;
/* write an array table to file */
void writeArrayTable(uint32_t fNumber, ftEntry_t* ft, uint32_t* funcCount) {
int outFile = getOutFile();
uint32_t arrayHeaderLocation = 0;
uint32_t arrayCurrentLocation = 0;
uint32_t arrayIterator = 0;
uint32_t functionUsed = 0;
uint32_t pathCounts = 0;
/* look through each entry in the array to determine whether the function
was executed at all */
for( arrayIterator = 0; arrayIterator < ft->size; arrayIterator++ ) {
uint32_t pc = ((uint32_t*)ft->array)[arrayIterator];
/* was this path executed? */
if( pc ) {
PathProfileTableEntry pte;
pte.pathNumber = arrayIterator;
pte.pathCounter = pc;
pathCounts++;
/* one-time initialization stuff */
if(!functionUsed) {
arrayHeaderLocation = lseek(outFile, 0, SEEK_CUR);
lseek(outFile, sizeof(PathProfileHeader), SEEK_CUR);
functionUsed = 1;
(*funcCount)++;
}
/* write path data */
if (write(outFile, &pte, sizeof(PathProfileTableEntry)) < 0) {
fprintf(stderr, "error: unable to write path entry to output file.\n");
return;
}
}
}
/* If this function was executed, write the header */
if( functionUsed ) {
PathProfileHeader fHeader;
fHeader.fnNumber = fNumber;
fHeader.numEntries = pathCounts;
arrayCurrentLocation = lseek(outFile, 0, SEEK_CUR);
lseek(outFile, arrayHeaderLocation, SEEK_SET);
if (write(outFile, &fHeader, sizeof(PathProfileHeader)) < 0) {
fprintf(stderr,
"error: unable to write function header to output file.\n");
return;
}
lseek(outFile, arrayCurrentLocation, SEEK_SET);
}
}
static uint32_t hash (uint32_t key) {
/* this may benefit from a proper hash function */
return key%ARBITRARY_HASH_BIN_COUNT;
}
/* output a specific function's hash table to the profile file */
void writeHashTable(uint32_t functionNumber, pathHashTable_t* hashTable) {
int outFile = getOutFile();
PathProfileHeader header;
uint32_t i;
header.fnNumber = functionNumber;
header.numEntries = hashTable->pathCounts;
if (write(outFile, &header, sizeof(PathProfileHeader)) < 0) {
fprintf(stderr, "error: unable to write function header to output file.\n");
return;
}
for (i = 0; i < ARBITRARY_HASH_BIN_COUNT; i++) {
pathHashEntry_t* hashEntry = hashTable->hashBins[i];
while (hashEntry) {
pathHashEntry_t* temp;
PathProfileTableEntry pte;
pte.pathNumber = hashEntry->pathNumber;
pte.pathCounter = hashEntry->pathCount;
if (write(outFile, &pte, sizeof(PathProfileTableEntry)) < 0) {
fprintf(stderr, "error: unable to write path entry to output file.\n");
return;
}
temp = hashEntry;
hashEntry = hashEntry->next;
free (temp);
}
}
}
/* Return a pointer to this path's specific path counter */
static uint32_t* getPathCounter(uint32_t functionNumber,
uint32_t pathNumber) {
pathHashTable_t* hashTable;
pathHashEntry_t* hashEntry;
uint32_t index = hash(pathNumber);
if( ft[functionNumber-1].array == 0)
ft[functionNumber-1].array = calloc(sizeof(pathHashTable_t), 1);
hashTable = (pathHashTable_t*)((ftEntry_t*)ft)[functionNumber-1].array;
hashEntry = hashTable->hashBins[index];
while (hashEntry) {
if (hashEntry->pathNumber == pathNumber) {
return &hashEntry->pathCount;
}
hashEntry = hashEntry->next;
}
hashEntry = malloc(sizeof(pathHashEntry_t));
hashEntry->pathNumber = pathNumber;
hashEntry->pathCount = 0;
hashEntry->next = hashTable->hashBins[index];
hashTable->hashBins[index] = hashEntry;
hashTable->pathCounts++;
return &hashEntry->pathCount;
}
/* Increment a specific path's count */
void llvm_increment_path_count (uint32_t functionNumber, uint32_t pathNumber) {
uint32_t* pathCounter = getPathCounter(functionNumber, pathNumber);
if( *pathCounter < 0xffffffff )
(*pathCounter)++;
}
/* Increment a specific path's count */
void llvm_decrement_path_count (uint32_t functionNumber, uint32_t pathNumber) {
uint32_t* pathCounter = getPathCounter(functionNumber, pathNumber);
(*pathCounter)--;
}
/*
* Writes out a path profile given a function table, in the following format.
*
*
* | <-- 32 bits --> |
* +-----------------+-----------------+
* 0x00 | profileType | functionCount |
* +-----------------+-----------------+
* 0x08 | functionNum | profileEntries | // function 1
* +-----------------+-----------------+
* 0x10 | pathNumber | pathCounter | // entry 1.1
* +-----------------+-----------------+
* 0x18 | pathNumber | pathCounter | // entry 1.2
* +-----------------+-----------------+
* ... | ... | ... | // entry 1.n
* +-----------------+-----------------+
* ... | functionNum | profileEntries | // function 2
* +-----------------+-----------------+
* ... | pathNumber | pathCounter | // entry 2.1
* +-----------------+-----------------+
* ... | pathNumber | pathCounter | // entry 2.2
* +-----------------+-----------------+
* ... | ... | ... | // entry 2.n
* +-----------------+-----------------+
*
*/
static void pathProfAtExitHandler(void) {
int outFile = getOutFile();
uint32_t i;
uint32_t header[2] = { PathInfo, 0 };
uint32_t headerLocation;
uint32_t currentLocation;
/* skip over the header for now */
headerLocation = lseek(outFile, 0, SEEK_CUR);
lseek(outFile, 2*sizeof(uint32_t), SEEK_CUR);
/* Iterate through each function */
for( i = 0; i < ftSize; i++ ) {
if( ft[i].type == ProfilingArray ) {
writeArrayTable(i+1,&ft[i],header + 1);
} else if( ft[i].type == ProfilingHash ) {
/* If the hash exists, write it to file */
if( ft[i].array ) {
writeHashTable(i+1,ft[i].array);
header[1]++;
free(ft[i].array);
}
}
}
/* Setup and write the path profile header */
currentLocation = lseek(outFile, 0, SEEK_CUR);
lseek(outFile, headerLocation, SEEK_SET);
if (write(outFile, header, sizeof(header)) < 0) {
fprintf(stderr,
"error: unable to write path profile header to output file.\n");
return;
}
lseek(outFile, currentLocation, SEEK_SET);
}
/* llvm_start_path_profiling - This is the main entry point of the path
* profiling library. It is responsible for setting up the atexit handler.
*/
int llvm_start_path_profiling(int argc, const char** argv,
void* functionTable, uint32_t numElements) {
int Ret = save_arguments(argc, argv);
ft = functionTable;
ftSize = numElements;
atexit(pathProfAtExitHandler);
return Ret;
}