GCDAProfiling.c revision 8c88119d6334a470e3ad638c5a1f1b42c4258ac9 
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 <stdio.h>
24#include <stdlib.h>
25#include <string.h>
26#include <sys/stat.h>
27#include <sys/types.h>
28#ifdef _WIN32
29#include <direct.h>
30#endif
31
32#ifndef _MSC_VER
33#include <stdint.h>
34#else
35typedef unsigned int uint32_t;
36typedef unsigned int uint64_t;
37#endif
38
39/* #define DEBUG_GCDAPROFILING */
40
41/*
42 * --- GCOV file format I/O primitives ---
43 */
44
45static FILE *output_file = NULL;
46
47static void write_int32(uint32_t i) {
48  fwrite(&i, 4, 1, output_file);
49}
50
51static void write_int64(uint64_t i) {
52  uint32_t lo, hi;
53  lo = i >>  0;
54  hi = i >> 32;
55
56  write_int32(lo);
57  write_int32(hi);
58}
59
60static uint32_t length_of_string(const char *s) {
61  return (strlen(s) / 4) + 1;
62}
63
64static void write_string(const char *s) {
65  uint32_t len = length_of_string(s);
66  write_int32(len);
67  fwrite(s, strlen(s), 1, output_file);
68  fwrite("\0\0\0\0", 4 - (strlen(s) % 4), 1, output_file);
69}
70
71static char *mangle_filename(const char *orig_filename) {
72  /* TODO: handle GCOV_PREFIX_STRIP */
73  const char *prefix;
74  char *filename = 0;
75
76  prefix = getenv("GCOV_PREFIX");
77
78  if (!prefix)
79    return strdup(orig_filename);
80
81  filename = malloc(strlen(prefix) + 1 + strlen(orig_filename) + 1);
82  strcpy(filename, prefix);
83  strcat(filename, "/");
84  strcat(filename, orig_filename);
85
86  return filename;
87}
88
89static void recursive_mkdir(const char *filename) {
90  char *pathname;
91  int i, e;
92
93  for (i = 1, e = strlen(filename); i != e; ++i) {
94    if (filename[i] == '/') {
95      pathname = malloc(i + 1);
96      strncpy(pathname, filename, i);
97      pathname[i] = '\0';
98#ifdef _WIN32
99      _mkdir(pathname);
100#else
101      mkdir(pathname, 0750);  /* some of these will fail, ignore it. */
102#endif
103      free(pathname);
104    }
105  }
106}
107
108/*
109 * --- LLVM line counter API ---
110 */
111
112/* A file in this case is a translation unit. Each .o file built with line
113 * profiling enabled will emit to a different file. Only one file may be
114 * started at a time.
115 */
116void llvm_gcda_start_file(const char *orig_filename) {
117  char *filename;
118  filename = mangle_filename(orig_filename);
119  recursive_mkdir(filename);
120  output_file = fopen(filename, "wb");
121
122  /* gcda file, version 404*, stamp LLVM. */
123#ifdef __APPLE__
124  fwrite("adcg*204MVLL", 12, 1, output_file);
125#else
126  fwrite("adcg*404MVLL", 12, 1, output_file);
127#endif
128
129#ifdef DEBUG_GCDAPROFILING
130  printf("llvmgcda: [%s]\n", orig_filename);
131#endif
132
133  free(filename);
134}
135
136/* Given an array of pointers to counters (counters), increment the n-th one,
137 * where we're also given a pointer to n (predecessor).
138 */
139void llvm_gcda_increment_indirect_counter(uint32_t *predecessor,
140                                          uint64_t **counters) {
141  uint64_t *counter;
142  uint32_t pred;
143
144  pred = *predecessor;
145  if (pred == 0xffffffff)
146    return;
147  counter = counters[pred];
148
149  /* Don't crash if the pred# is out of sync. This can happen due to threads,
150     or because of a TODO in GCOVProfiling.cpp buildEdgeLookupTable(). */
151  if (counter)
152    ++*counter;
153#ifdef DEBUG_GCDAPROFILING
154  else
155    printf("llvmgcda: increment_indirect_counter counters=%x, pred=%u\n",
156           state_table_row, *predecessor);
157#endif
158}
159
160void llvm_gcda_emit_function(uint32_t ident, const char *function_name) {
161#ifdef DEBUG_GCDAPROFILING
162  printf("llvmgcda: function id=%x\n", ident);
163#endif
164
165  /* function tag */
166  fwrite("\0\0\0\1", 4, 1, output_file);
167  write_int32(3 + 1 + length_of_string(function_name));
168  write_int32(ident);
169  write_int32(0);
170  write_int32(0);
171  write_string(function_name);
172}
173
174void llvm_gcda_emit_arcs(uint32_t num_counters, uint64_t *counters) {
175  uint32_t i;
176  /* counter #1 (arcs) tag */
177  fwrite("\0\0\xa1\1", 4, 1, output_file);
178  write_int32(num_counters * 2);
179  for (i = 0; i < num_counters; ++i) {
180    write_int64(counters[i]);
181  }
182
183#ifdef DEBUG_GCDAPROFILING
184  printf("llvmgcda:   %u arcs\n", num_counters);
185  for (i = 0; i < num_counters; ++i) {
186    printf("llvmgcda:   %llu\n", (unsigned long long)counters[i]);
187  }
188#endif
189}
190
191void llvm_gcda_end_file() {
192  /* Write out EOF record. */
193  fwrite("\0\0\0\0\0\0\0\0", 8, 1, output_file);
194  fclose(output_file);
195  output_file = NULL;
196
197#ifdef DEBUG_GCDAPROFILING
198  printf("llvmgcda: -----\n");
199#endif
200}
201