1 /*===- InstrProfilingFile.c - Write instrumentation to a file -------------===*\
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 #include "InstrProfiling.h"
11 #include <errno.h>
12 #include <stdio.h>
13 #include <stdlib.h>
14 #include <string.h>
15
16 #define UNCONST(ptr) ((void *)(uintptr_t)(ptr))
17
writeFile(FILE * File)18 static int writeFile(FILE *File) {
19 /* Match logic in __llvm_profile_write_buffer(). */
20 const __llvm_profile_data *DataBegin = __llvm_profile_begin_data();
21 const __llvm_profile_data *DataEnd = __llvm_profile_end_data();
22 const uint64_t *CountersBegin = __llvm_profile_begin_counters();
23 const uint64_t *CountersEnd = __llvm_profile_end_counters();
24 const char *NamesBegin = __llvm_profile_begin_names();
25 const char *NamesEnd = __llvm_profile_end_names();
26
27 /* Calculate size of sections. */
28 const uint64_t DataSize = DataEnd - DataBegin;
29 const uint64_t CountersSize = CountersEnd - CountersBegin;
30 const uint64_t NamesSize = NamesEnd - NamesBegin;
31 const uint64_t Padding = sizeof(uint64_t) - NamesSize % sizeof(uint64_t);
32
33 /* Enough zeroes for padding. */
34 const char Zeroes[sizeof(uint64_t)] = {0};
35
36 /* Create the header. */
37 uint64_t Header[PROFILE_HEADER_SIZE];
38 Header[0] = __llvm_profile_get_magic();
39 Header[1] = __llvm_profile_get_version();
40 Header[2] = DataSize;
41 Header[3] = CountersSize;
42 Header[4] = NamesSize;
43 Header[5] = (uintptr_t)CountersBegin;
44 Header[6] = (uintptr_t)NamesBegin;
45
46 /* Write the data. */
47 #define CHECK_fwrite(Data, Size, Length, File) \
48 do { if (fwrite(Data, Size, Length, File) != Length) return -1; } while (0)
49 CHECK_fwrite(Header, sizeof(uint64_t), PROFILE_HEADER_SIZE, File);
50 CHECK_fwrite(DataBegin, sizeof(__llvm_profile_data), DataSize, File);
51 CHECK_fwrite(CountersBegin, sizeof(uint64_t), CountersSize, File);
52 CHECK_fwrite(NamesBegin, sizeof(char), NamesSize, File);
53 CHECK_fwrite(Zeroes, sizeof(char), Padding, File);
54 #undef CHECK_fwrite
55
56 return 0;
57 }
58
writeFileWithName(const char * OutputName)59 static int writeFileWithName(const char *OutputName) {
60 int RetVal;
61 FILE *OutputFile;
62 if (!OutputName || !OutputName[0])
63 return -1;
64
65 /* Append to the file to support profiling multiple shared objects. */
66 OutputFile = fopen(OutputName, "a");
67 if (!OutputFile)
68 return -1;
69
70 RetVal = writeFile(OutputFile);
71
72 fclose(OutputFile);
73 return RetVal;
74 }
75
76 __attribute__((weak)) int __llvm_profile_OwnsFilename = 0;
77 __attribute__((weak)) const char *__llvm_profile_CurrentFilename = NULL;
78
setFilename(const char * Filename,int OwnsFilename)79 static void setFilename(const char *Filename, int OwnsFilename) {
80 if (__llvm_profile_OwnsFilename)
81 free(UNCONST(__llvm_profile_CurrentFilename));
82
83 __llvm_profile_CurrentFilename = Filename;
84 __llvm_profile_OwnsFilename = OwnsFilename;
85 }
86
truncateCurrentFile(void)87 static void truncateCurrentFile(void) {
88 const char *Filename;
89 FILE *File;
90
91 Filename = __llvm_profile_CurrentFilename;
92 if (!Filename || !Filename[0])
93 return;
94
95 /* Truncate the file. Later we'll reopen and append. */
96 File = fopen(Filename, "w");
97 if (!File)
98 return;
99 fclose(File);
100 }
101
setDefaultFilename(void)102 static void setDefaultFilename(void) { setFilename("default.profraw", 0); }
103
104 int getpid(void);
setFilenameFromEnvironment(void)105 static int setFilenameFromEnvironment(void) {
106 const char *Filename = getenv("LLVM_PROFILE_FILE");
107 #define MAX_PID_SIZE 16
108 char PidChars[MAX_PID_SIZE] = {0};
109 int NumPids = 0, PidLength = 0;
110 char *Allocated;
111 int I, J;
112
113 if (!Filename || !Filename[0])
114 return -1;
115
116 /* Check the filename for "%p", which indicates a pid-substitution. */
117 for (I = 0; Filename[I]; ++I)
118 if (Filename[I] == '%' && Filename[++I] == 'p')
119 if (!NumPids++) {
120 PidLength = snprintf(PidChars, MAX_PID_SIZE, "%d", getpid());
121 if (PidLength <= 0)
122 return -1;
123 }
124 if (!NumPids) {
125 setFilename(Filename, 0);
126 return 0;
127 }
128
129 /* Allocate enough space for the substituted filename. */
130 Allocated = malloc(I + NumPids*(PidLength - 2) + 1);
131 if (!Allocated)
132 return -1;
133
134 /* Construct the new filename. */
135 for (I = 0, J = 0; Filename[I]; ++I)
136 if (Filename[I] == '%') {
137 if (Filename[++I] == 'p') {
138 memcpy(Allocated + J, PidChars, PidLength);
139 J += PidLength;
140 }
141 /* Drop any unknown substitutions. */
142 } else
143 Allocated[J++] = Filename[I];
144 Allocated[J] = 0;
145
146 /* Use the computed name. */
147 setFilename(Allocated, 1);
148 return 0;
149 }
150
setFilenameAutomatically(void)151 static void setFilenameAutomatically(void) {
152 if (!setFilenameFromEnvironment())
153 return;
154
155 setDefaultFilename();
156 }
157
158 __attribute__((visibility("hidden")))
__llvm_profile_initialize_file(void)159 void __llvm_profile_initialize_file(void) {
160 /* Check if the filename has been initialized. */
161 if (__llvm_profile_CurrentFilename)
162 return;
163
164 /* Detect the filename and truncate. */
165 setFilenameAutomatically();
166 truncateCurrentFile();
167 }
168
169 __attribute__((visibility("hidden")))
__llvm_profile_set_filename(const char * Filename)170 void __llvm_profile_set_filename(const char *Filename) {
171 setFilename(Filename, 0);
172 truncateCurrentFile();
173 }
174
175 __attribute__((visibility("hidden")))
__llvm_profile_write_file(void)176 int __llvm_profile_write_file(void) {
177 int rc;
178
179 /* Check the filename. */
180 if (!__llvm_profile_CurrentFilename)
181 return -1;
182
183 /* Write the file. */
184 rc = writeFileWithName(__llvm_profile_CurrentFilename);
185 if (rc && getenv("LLVM_PROFILE_VERBOSE_ERRORS"))
186 fprintf(stderr, "LLVM Profile: Failed to write file \"%s\": %s\n",
187 __llvm_profile_CurrentFilename, strerror(errno));
188 return rc;
189 }
190
writeFileWithoutReturn(void)191 static void writeFileWithoutReturn(void) {
192 __llvm_profile_write_file();
193 }
194
195 __attribute__((visibility("hidden")))
__llvm_profile_register_write_file_atexit(void)196 int __llvm_profile_register_write_file_atexit(void) {
197 static int HasBeenRegistered = 0;
198
199 if (HasBeenRegistered)
200 return 0;
201
202 HasBeenRegistered = 1;
203 return atexit(writeFileWithoutReturn);
204 }
205