src/compiler-rt/lib/profile/InstrProfilingFile.c

   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 "InstrProfilingUtil.h"
  12 #include <errno.h>
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <string.h>
  16
  17 #define UNCONST(ptr) ((void *)(uintptr_t)(ptr))
  18
  19 static int writeFile(FILE *File) {
  20   /* Match logic in __llvm_profile_write_buffer(). */
  21   const __llvm_profile_data *DataBegin = __llvm_profile_begin_data();
  22   const __llvm_profile_data *DataEnd = __llvm_profile_end_data();
  23   const uint64_t *CountersBegin = __llvm_profile_begin_counters();
  24   const uint64_t *CountersEnd   = __llvm_profile_end_counters();
  25   const char *NamesBegin = __llvm_profile_begin_names();
  26   const char *NamesEnd   = __llvm_profile_end_names();
  27
  28   /* Calculate size of sections. */
  29   const uint64_t DataSize = DataEnd - DataBegin;
  30   const uint64_t CountersSize = CountersEnd - CountersBegin;
  31   const uint64_t NamesSize = NamesEnd - NamesBegin;
  32   const uint64_t Padding = sizeof(uint64_t) - NamesSize % sizeof(uint64_t);
  33
  34   /* Enough zeroes for padding. */
  35   const char Zeroes[sizeof(uint64_t)] = {0};
  36
  37   /* Create the header. */
  38   __llvm_profile_header Header;
  39   Header.Magic = __llvm_profile_get_magic();
  40   Header.Version = __llvm_profile_get_version();
  41   Header.DataSize = DataSize;
  42   Header.CountersSize = CountersSize;
  43   Header.NamesSize = NamesSize;
  44   Header.CountersDelta = (uintptr_t)CountersBegin;
  45   Header.NamesDelta = (uintptr_t)NamesBegin;
  46
  47   /* Write the data. */
  48 #define CHECK_fwrite(Data, Size, Length, File) \
  49   do { if (fwrite(Data, Size, Length, File) != Length) return -1; } while (0)
  50   CHECK_fwrite(&Header,        sizeof(__llvm_profile_header), 1, File);
  51   CHECK_fwrite(DataBegin,     sizeof(__llvm_profile_data), DataSize, File);
  52   CHECK_fwrite(CountersBegin, sizeof(uint64_t), CountersSize, File);
  53   CHECK_fwrite(NamesBegin,    sizeof(char), NamesSize, File);
  54   CHECK_fwrite(Zeroes,        sizeof(char), Padding, File);
  55 #undef CHECK_fwrite
  56
  57   return 0;
  58 }
  59
  60 static int writeFileWithName(const char *OutputName) {
  61   int RetVal;
  62   FILE *OutputFile;
  63   if (!OutputName || !OutputName[0])
  64     return -1;
  65
  66   /* Append to the file to support profiling multiple shared objects. */
  67   OutputFile = fopen(OutputName, "a");
  68   if (!OutputFile)
  69     return -1;
  70
  71   RetVal = writeFile(OutputFile);
  72
  73   fclose(OutputFile);
  74   return RetVal;
  75 }
  76
  77 __attribute__((weak)) int __llvm_profile_OwnsFilename = 0;
  78 __attribute__((weak)) const char *__llvm_profile_CurrentFilename = NULL;
  79
  80 static void truncateCurrentFile(void) {
  81   const char *Filename;
  82   FILE *File;
  83
  84   Filename = __llvm_profile_CurrentFilename;
  85   if (!Filename || !Filename[0])
  86     return;
  87
  88   /* Create the directory holding the file, if needed. */
  89   if (strchr(Filename, '/')) {
  90     char *Copy = malloc(strlen(Filename) + 1);
  91     strcpy(Copy, Filename);
  92     __llvm_profile_recursive_mkdir(Copy);
  93     free(Copy);
  94   }
  95
  96   /* Truncate the file.  Later we'll reopen and append. */
  97   File = fopen(Filename, "w");
  98   if (!File)
  99     return;
 100   fclose(File);
 101 }
 102
 103 static void setFilename(const char *Filename, int OwnsFilename) {
 104   /* Check if this is a new filename and therefore needs truncation. */
 105   int NewFile = !__llvm_profile_CurrentFilename ||
 106       (Filename && strcmp(Filename, __llvm_profile_CurrentFilename));
 107   if (__llvm_profile_OwnsFilename)
 108     free(UNCONST(__llvm_profile_CurrentFilename));
 109
 110   __llvm_profile_CurrentFilename = Filename;
 111   __llvm_profile_OwnsFilename = OwnsFilename;
 112
 113   /* If not a new file, append to support profiling multiple shared objects. */
 114   if (NewFile)
 115     truncateCurrentFile();
 116 }
 117
 118 static void resetFilenameToDefault(void) { setFilename("default.profraw", 0); }
 119
 120 int getpid(void);
 121 static int setFilenamePossiblyWithPid(const char *Filename) {
 122 #define MAX_PID_SIZE 16
 123   char PidChars[MAX_PID_SIZE] = {0};
 124   int NumPids = 0, PidLength = 0;
 125   char *Allocated;
 126   int I, J;
 127
 128   /* Reset filename on NULL, except with env var which is checked by caller. */
 129   if (!Filename) {
 130     resetFilenameToDefault();
 131     return 0;
 132   }
 133
 134   /* Check the filename for "%p", which indicates a pid-substitution. */
 135   for (I = 0; Filename[I]; ++I)
 136     if (Filename[I] == '%' && Filename[++I] == 'p')
 137       if (!NumPids++) {
 138         PidLength = snprintf(PidChars, MAX_PID_SIZE, "%d", getpid());
 139         if (PidLength <= 0)
 140           return -1;
 141       }
 142   if (!NumPids) {
 143     setFilename(Filename, 0);
 144     return 0;
 145   }
 146
 147   /* Allocate enough space for the substituted filename. */
 148   Allocated = malloc(I + NumPids*(PidLength - 2) + 1);
 149   if (!Allocated)
 150     return -1;
 151
 152   /* Construct the new filename. */
 153   for (I = 0, J = 0; Filename[I]; ++I)
 154     if (Filename[I] == '%') {
 155       if (Filename[++I] == 'p') {
 156         memcpy(Allocated + J, PidChars, PidLength);
 157         J += PidLength;
 158       }
 159       /* Drop any unknown substitutions. */
 160     } else
 161       Allocated[J++] = Filename[I];
 162   Allocated[J] = 0;
 163
 164   /* Use the computed name. */
 165   setFilename(Allocated, 1);
 166   return 0;
 167 }
 168
 169 static int setFilenameFromEnvironment(void) {
 170   const char *Filename = getenv("LLVM_PROFILE_FILE");
 171
 172   if (!Filename || !Filename[0])
 173     return -1;
 174
 175   return setFilenamePossiblyWithPid(Filename);
 176 }
 177
 178 static void setFilenameAutomatically(void) {
 179   if (!setFilenameFromEnvironment())
 180     return;
 181
 182   resetFilenameToDefault();
 183 }
 184
 185 __attribute__((visibility("hidden")))
 186 void __llvm_profile_initialize_file(void) {
 187   /* Check if the filename has been initialized. */
 188   if (__llvm_profile_CurrentFilename)
 189     return;
 190
 191   /* Detect the filename and truncate. */
 192   setFilenameAutomatically();
 193 }
 194
 195 __attribute__((visibility("hidden")))
 196 void __llvm_profile_set_filename(const char *Filename) {
 197   setFilenamePossiblyWithPid(Filename);
 198 }
 199
 200 __attribute__((visibility("hidden")))
 201 void __llvm_profile_override_default_filename(const char *Filename) {
 202   /* If the env var is set, skip setting filename from argument. */
 203   const char *Env_Filename = getenv("LLVM_PROFILE_FILE");
 204   if (Env_Filename && Env_Filename[0])
 205     return;
 206   setFilenamePossiblyWithPid(Filename);
 207 }
 208
 209 __attribute__((visibility("hidden")))
 210 int __llvm_profile_write_file(void) {
 211   int rc;
 212
 213   /* Check the filename. */
 214   if (!__llvm_profile_CurrentFilename)
 215     return -1;
 216
 217   /* Write the file. */
 218   rc = writeFileWithName(__llvm_profile_CurrentFilename);
 219   if (rc && getenv("LLVM_PROFILE_VERBOSE_ERRORS"))
 220     fprintf(stderr, "LLVM Profile: Failed to write file \"%s\": %s\n",
 221             __llvm_profile_CurrentFilename, strerror(errno));
 222   return rc;
 223 }
 224
 225 static void writeFileWithoutReturn(void) {
 226   __llvm_profile_write_file();
 227 }
 228
 229 __attribute__((visibility("hidden")))
 230 int __llvm_profile_register_write_file_atexit(void) {
 231   static int HasBeenRegistered = 0;
 232
 233   if (HasBeenRegistered)
 234     return 0;
 235
 236   HasBeenRegistered = 1;
 237   return atexit(writeFileWithoutReturn);
 238 }