1 /*===- GCDAProfiling.c - Support library for GCDA file emission -----------===*\
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 gcov profiling
11 |* instrumentation pass. Link against this library when running code through
12 |* the -insert-gcov-profiling LLVM pass.
13 |*
14 |* We emit files in a corrupt version of GCOV's "gcda" file format. These files
15 |* are only close enough that LCOV will happily parse them. Anything that lcov
16 |* ignores is missing.
17 |*
18 |* TODO: gcov is multi-process safe by having each exit open the existing file
19 |* and append to it. We'd like to achieve that and be thread-safe too.
20 |*
21 \*===----------------------------------------------------------------------===*/
22
23 #include "llvm/Support/DataTypes.h"
24 #include <stdio.h>
25 #include <stdlib.h>
26 #include <string.h>
27 #include <sys/stat.h>
28 #include <sys/types.h>
29 #ifdef _WIN32
30 #include <direct.h>
31 #endif
32
33 /* #define DEBUG_GCDAPROFILING */
34
35 /*
36 * --- GCOV file format I/O primitives ---
37 */
38
39 static FILE *output_file = NULL;
40
write_int32(uint32_t i)41 static void write_int32(uint32_t i) {
42 fwrite(&i, 4, 1, output_file);
43 }
44
write_int64(uint64_t i)45 static void write_int64(uint64_t i) {
46 uint32_t lo, hi;
47 lo = i >> 0;
48 hi = i >> 32;
49
50 write_int32(lo);
51 write_int32(hi);
52 }
53
length_of_string(const char * s)54 static uint32_t length_of_string(const char *s) {
55 return (strlen(s) / 4) + 1;
56 }
57
write_string(const char * s)58 static void write_string(const char *s) {
59 uint32_t len = length_of_string(s);
60 write_int32(len);
61 fwrite(s, strlen(s), 1, output_file);
62 fwrite("\0\0\0\0", 4 - (strlen(s) % 4), 1, output_file);
63 }
64
mangle_filename(const char * orig_filename)65 static char *mangle_filename(const char *orig_filename) {
66 /* TODO: handle GCOV_PREFIX_STRIP */
67 const char *prefix;
68 char *filename = 0;
69
70 prefix = getenv("GCOV_PREFIX");
71
72 if (!prefix)
73 return strdup(orig_filename);
74
75 filename = malloc(strlen(prefix) + 1 + strlen(orig_filename) + 1);
76 strcpy(filename, prefix);
77 strcat(filename, "/");
78 strcat(filename, orig_filename);
79
80 return filename;
81 }
82
recursive_mkdir(const char * filename)83 static void recursive_mkdir(const char *filename) {
84 char *pathname;
85 int i, e;
86
87 for (i = 1, e = strlen(filename); i != e; ++i) {
88 if (filename[i] == '/') {
89 pathname = malloc(i + 1);
90 strncpy(pathname, filename, i);
91 pathname[i] = '\0';
92 #ifdef _WIN32
93 _mkdir(pathname);
94 #else
95 mkdir(pathname, 0750); /* some of these will fail, ignore it. */
96 #endif
97 free(pathname);
98 }
99 }
100 }
101
102 /*
103 * --- LLVM line counter API ---
104 */
105
106 /* A file in this case is a translation unit. Each .o file built with line
107 * profiling enabled will emit to a different file. Only one file may be
108 * started at a time.
109 */
llvm_gcda_start_file(const char * orig_filename)110 void llvm_gcda_start_file(const char *orig_filename) {
111 char *filename;
112 filename = mangle_filename(orig_filename);
113 recursive_mkdir(filename);
114 output_file = fopen(filename, "wb");
115
116 /* gcda file, version 404*, stamp LLVM. */
117 #ifdef __APPLE__
118 fwrite("adcg*204MVLL", 12, 1, output_file);
119 #else
120 fwrite("adcg*404MVLL", 12, 1, output_file);
121 #endif
122
123 #ifdef DEBUG_GCDAPROFILING
124 printf("llvmgcda: [%s]\n", orig_filename);
125 #endif
126
127 free(filename);
128 }
129
130 /* Given an array of pointers to counters (counters), increment the n-th one,
131 * where we're also given a pointer to n (predecessor).
132 */
llvm_gcda_increment_indirect_counter(uint32_t * predecessor,uint64_t ** counters)133 void llvm_gcda_increment_indirect_counter(uint32_t *predecessor,
134 uint64_t **counters) {
135 uint64_t *counter;
136 uint32_t pred;
137
138 pred = *predecessor;
139 if (pred == 0xffffffff)
140 return;
141 counter = counters[pred];
142
143 /* Don't crash if the pred# is out of sync. This can happen due to threads,
144 or because of a TODO in GCOVProfiling.cpp buildEdgeLookupTable(). */
145 if (counter)
146 ++*counter;
147 #ifdef DEBUG_GCDAPROFILING
148 else
149 printf("llvmgcda: increment_indirect_counter counters=%x, pred=%u\n",
150 state_table_row, *predecessor);
151 #endif
152 }
153
llvm_gcda_emit_function(uint32_t ident,const char * function_name)154 void llvm_gcda_emit_function(uint32_t ident, const char *function_name) {
155 #ifdef DEBUG_GCDAPROFILING
156 printf("llvmgcda: function id=%x\n", ident);
157 #endif
158
159 /* function tag */
160 fwrite("\0\0\0\1", 4, 1, output_file);
161 write_int32(3 + 1 + length_of_string(function_name));
162 write_int32(ident);
163 write_int32(0);
164 write_int32(0);
165 write_string(function_name);
166 }
167
llvm_gcda_emit_arcs(uint32_t num_counters,uint64_t * counters)168 void llvm_gcda_emit_arcs(uint32_t num_counters, uint64_t *counters) {
169 uint32_t i;
170 /* counter #1 (arcs) tag */
171 fwrite("\0\0\xa1\1", 4, 1, output_file);
172 write_int32(num_counters * 2);
173 for (i = 0; i < num_counters; ++i) {
174 write_int64(counters[i]);
175 }
176
177 #ifdef DEBUG_GCDAPROFILING
178 printf("llvmgcda: %u arcs\n", num_counters);
179 for (i = 0; i < num_counters; ++i) {
180 printf("llvmgcda: %llu\n", (unsigned long long)counters[i]);
181 }
182 #endif
183 }
184
llvm_gcda_end_file()185 void llvm_gcda_end_file() {
186 /* Write out EOF record. */
187 fwrite("\0\0\0\0\0\0\0\0", 8, 1, output_file);
188 fclose(output_file);
189 output_file = NULL;
190
191 #ifdef DEBUG_GCDAPROFILING
192 printf("llvmgcda: -----\n");
193 #endif
194 }
195