1 /*===-- PathProfiling.c - Support library for path profiling --------------===*\
2 |*
3 |* The LLVM Compiler Infrastructure
4 |*
5 |* This file is distributed under the University of Illinois Open Source
6 |* License. See LICENSE.TXT for details.
7 |*
8 |*===----------------------------------------------------------------------===*|
9 |*
10 |* This file implements the call back routines for the path profiling
11 |* instrumentation pass. This should be used with the -insert-path-profiling
12 |* LLVM pass.
13 |*
14 \*===----------------------------------------------------------------------===*/
15
16 #include "Profiling.h"
17 #include "llvm/Analysis/ProfileInfoTypes.h"
18 #include "llvm/Support/DataTypes.h"
19 #include <sys/types.h>
20 #if !defined(_MSC_VER) && !defined(__MINGW32__)
21 #include <unistd.h>
22 #else
23 #include <io.h>
24 #endif
25 #include <string.h>
26 #include <stdlib.h>
27 #include <stdio.h>
28
29 /* note that this is used for functions with large path counts,
30 but it is unlikely those paths will ALL be executed */
31 #define ARBITRARY_HASH_BIN_COUNT 100
32
33 typedef struct pathHashEntry_s {
34 uint32_t pathNumber;
35 uint32_t pathCount;
36 struct pathHashEntry_s* next;
37 } pathHashEntry_t;
38
39 typedef struct pathHashTable_s {
40 pathHashEntry_t* hashBins[ARBITRARY_HASH_BIN_COUNT];
41 uint32_t pathCounts;
42 } pathHashTable_t;
43
44 typedef struct {
45 enum ProfilingStorageType type;
46 uint32_t size;
47 void* array;
48 } ftEntry_t;
49
50 /* pointer to the function table allocated in the instrumented program */
51 ftEntry_t* ft;
52 uint32_t ftSize;
53
54 /* write an array table to file */
writeArrayTable(uint32_t fNumber,ftEntry_t * ft,uint32_t * funcCount)55 void writeArrayTable(uint32_t fNumber, ftEntry_t* ft, uint32_t* funcCount) {
56 int outFile = getOutFile();
57 uint32_t arrayHeaderLocation = 0;
58 uint32_t arrayCurrentLocation = 0;
59 uint32_t arrayIterator = 0;
60 uint32_t functionUsed = 0;
61 uint32_t pathCounts = 0;
62
63 /* look through each entry in the array to determine whether the function
64 was executed at all */
65 for( arrayIterator = 0; arrayIterator < ft->size; arrayIterator++ ) {
66 uint32_t pc = ((uint32_t*)ft->array)[arrayIterator];
67
68 /* was this path executed? */
69 if( pc ) {
70 PathProfileTableEntry pte;
71 pte.pathNumber = arrayIterator;
72 pte.pathCounter = pc;
73 pathCounts++;
74
75 /* one-time initialization stuff */
76 if(!functionUsed) {
77 arrayHeaderLocation = lseek(outFile, 0, SEEK_CUR);
78 lseek(outFile, sizeof(PathProfileHeader), SEEK_CUR);
79 functionUsed = 1;
80 (*funcCount)++;
81 }
82
83 /* write path data */
84 if (write(outFile, &pte, sizeof(PathProfileTableEntry)) < 0) {
85 fprintf(stderr, "error: unable to write path entry to output file.\n");
86 return;
87 }
88 }
89 }
90
91 /* If this function was executed, write the header */
92 if( functionUsed ) {
93 PathProfileHeader fHeader;
94 fHeader.fnNumber = fNumber;
95 fHeader.numEntries = pathCounts;
96
97 arrayCurrentLocation = lseek(outFile, 0, SEEK_CUR);
98 lseek(outFile, arrayHeaderLocation, SEEK_SET);
99
100 if (write(outFile, &fHeader, sizeof(PathProfileHeader)) < 0) {
101 fprintf(stderr,
102 "error: unable to write function header to output file.\n");
103 return;
104 }
105
106 lseek(outFile, arrayCurrentLocation, SEEK_SET);
107 }
108 }
109
hash(uint32_t key)110 static uint32_t hash (uint32_t key) {
111 /* this may benefit from a proper hash function */
112 return key%ARBITRARY_HASH_BIN_COUNT;
113 }
114
115 /* output a specific function's hash table to the profile file */
writeHashTable(uint32_t functionNumber,pathHashTable_t * hashTable)116 void writeHashTable(uint32_t functionNumber, pathHashTable_t* hashTable) {
117 int outFile = getOutFile();
118 PathProfileHeader header;
119 uint32_t i;
120
121 header.fnNumber = functionNumber;
122 header.numEntries = hashTable->pathCounts;
123
124 if (write(outFile, &header, sizeof(PathProfileHeader)) < 0) {
125 fprintf(stderr, "error: unable to write function header to output file.\n");
126 return;
127 }
128
129 for (i = 0; i < ARBITRARY_HASH_BIN_COUNT; i++) {
130 pathHashEntry_t* hashEntry = hashTable->hashBins[i];
131
132 while (hashEntry) {
133 pathHashEntry_t* temp;
134
135 PathProfileTableEntry pte;
136 pte.pathNumber = hashEntry->pathNumber;
137 pte.pathCounter = hashEntry->pathCount;
138
139 if (write(outFile, &pte, sizeof(PathProfileTableEntry)) < 0) {
140 fprintf(stderr, "error: unable to write path entry to output file.\n");
141 return;
142 }
143
144 temp = hashEntry;
145 hashEntry = hashEntry->next;
146 free (temp);
147
148 }
149 }
150 }
151
152 /* Return a pointer to this path's specific path counter */
getPathCounter(uint32_t functionNumber,uint32_t pathNumber)153 static uint32_t* getPathCounter(uint32_t functionNumber,
154 uint32_t pathNumber) {
155 pathHashTable_t* hashTable;
156 pathHashEntry_t* hashEntry;
157 uint32_t index = hash(pathNumber);
158
159 if( ft[functionNumber-1].array == 0)
160 ft[functionNumber-1].array = calloc(sizeof(pathHashTable_t), 1);
161
162 hashTable = (pathHashTable_t*)((ftEntry_t*)ft)[functionNumber-1].array;
163 hashEntry = hashTable->hashBins[index];
164
165 while (hashEntry) {
166 if (hashEntry->pathNumber == pathNumber) {
167 return &hashEntry->pathCount;
168 }
169
170 hashEntry = hashEntry->next;
171 }
172
173 hashEntry = malloc(sizeof(pathHashEntry_t));
174 hashEntry->pathNumber = pathNumber;
175 hashEntry->pathCount = 0;
176 hashEntry->next = hashTable->hashBins[index];
177 hashTable->hashBins[index] = hashEntry;
178 hashTable->pathCounts++;
179 return &hashEntry->pathCount;
180 }
181
182 /* Increment a specific path's count */
llvm_increment_path_count(uint32_t functionNumber,uint32_t pathNumber)183 void llvm_increment_path_count (uint32_t functionNumber, uint32_t pathNumber) {
184 uint32_t* pathCounter = getPathCounter(functionNumber, pathNumber);
185 if( *pathCounter < 0xffffffff )
186 (*pathCounter)++;
187 }
188
189 /* Increment a specific path's count */
llvm_decrement_path_count(uint32_t functionNumber,uint32_t pathNumber)190 void llvm_decrement_path_count (uint32_t functionNumber, uint32_t pathNumber) {
191 uint32_t* pathCounter = getPathCounter(functionNumber, pathNumber);
192 (*pathCounter)--;
193 }
194
195 /*
196 * Writes out a path profile given a function table, in the following format.
197 *
198 *
199 * | <-- 32 bits --> |
200 * +-----------------+-----------------+
201 * 0x00 | profileType | functionCount |
202 * +-----------------+-----------------+
203 * 0x08 | functionNum | profileEntries | // function 1
204 * +-----------------+-----------------+
205 * 0x10 | pathNumber | pathCounter | // entry 1.1
206 * +-----------------+-----------------+
207 * 0x18 | pathNumber | pathCounter | // entry 1.2
208 * +-----------------+-----------------+
209 * ... | ... | ... | // entry 1.n
210 * +-----------------+-----------------+
211 * ... | functionNum | profileEntries | // function 2
212 * +-----------------+-----------------+
213 * ... | pathNumber | pathCounter | // entry 2.1
214 * +-----------------+-----------------+
215 * ... | pathNumber | pathCounter | // entry 2.2
216 * +-----------------+-----------------+
217 * ... | ... | ... | // entry 2.n
218 * +-----------------+-----------------+
219 *
220 */
pathProfAtExitHandler(void)221 static void pathProfAtExitHandler(void) {
222 int outFile = getOutFile();
223 uint32_t i;
224 uint32_t header[2] = { PathInfo, 0 };
225 uint32_t headerLocation;
226 uint32_t currentLocation;
227
228 /* skip over the header for now */
229 headerLocation = lseek(outFile, 0, SEEK_CUR);
230 lseek(outFile, 2*sizeof(uint32_t), SEEK_CUR);
231
232 /* Iterate through each function */
233 for( i = 0; i < ftSize; i++ ) {
234 if( ft[i].type == ProfilingArray ) {
235 writeArrayTable(i+1,&ft[i],header + 1);
236
237 } else if( ft[i].type == ProfilingHash ) {
238 /* If the hash exists, write it to file */
239 if( ft[i].array ) {
240 writeHashTable(i+1,ft[i].array);
241 header[1]++;
242 free(ft[i].array);
243 }
244 }
245 }
246
247 /* Setup and write the path profile header */
248 currentLocation = lseek(outFile, 0, SEEK_CUR);
249 lseek(outFile, headerLocation, SEEK_SET);
250
251 if (write(outFile, header, sizeof(header)) < 0) {
252 fprintf(stderr,
253 "error: unable to write path profile header to output file.\n");
254 return;
255 }
256
257 lseek(outFile, currentLocation, SEEK_SET);
258 }
259 /* llvm_start_path_profiling - This is the main entry point of the path
260 * profiling library. It is responsible for setting up the atexit handler.
261 */
llvm_start_path_profiling(int argc,const char ** argv,void * functionTable,uint32_t numElements)262 int llvm_start_path_profiling(int argc, const char** argv,
263 void* functionTable, uint32_t numElements) {
264 int Ret = save_arguments(argc, argv);
265 ft = functionTable;
266 ftSize = numElements;
267 atexit(pathProfAtExitHandler);
268
269 return Ret;
270 }
271