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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 "InstrProfilingInternal.h"
12 #include "InstrProfilingUtil.h"
13 #include <errno.h>
14 #include <stdio.h>
15 #include <stdlib.h>
16 #include <string.h>
17 #ifdef _MSC_VER
18 /* For _alloca. */
19 #include <malloc.h>
20 #endif
21 #if defined(_WIN32)
22 #include "WindowsMMap.h"
23 /* For _chsize_s */
24 #include <io.h>
25 #else
26 #include <sys/file.h>
27 #include <sys/mman.h>
28 #include <unistd.h>
29 #if defined(__linux__)
30 #include <sys/types.h>
31 #endif
32 #endif
33 
34 /* From where is profile name specified.
35  * The order the enumerators define their
36  * precedence. Re-order them may lead to
37  * runtime behavior change. */
38 typedef enum ProfileNameSpecifier {
39   PNS_unknown = 0,
40   PNS_default,
41   PNS_command_line,
42   PNS_environment,
43   PNS_runtime_api
44 } ProfileNameSpecifier;
45 
getPNSStr(ProfileNameSpecifier PNS)46 static const char *getPNSStr(ProfileNameSpecifier PNS) {
47   switch (PNS) {
48   case PNS_default:
49     return "default setting";
50   case PNS_command_line:
51     return "command line";
52   case PNS_environment:
53     return "environment variable";
54   case PNS_runtime_api:
55     return "runtime API";
56   default:
57     return "Unknown";
58   }
59 }
60 
61 #define MAX_PID_SIZE 16
62 /* Data structure holding the result of parsed filename pattern.  */
63 typedef struct lprofFilename {
64   /* File name string possibly with %p or %h specifiers. */
65   const char *FilenamePat;
66   char PidChars[MAX_PID_SIZE];
67   char Hostname[COMPILER_RT_MAX_HOSTLEN];
68   unsigned NumPids;
69   unsigned NumHosts;
70   /* When in-process merging is enabled, this parameter specifies
71    * the total number of profile data files shared by all the processes
72    * spawned from the same binary. By default the value is 1. If merging
73    * is not enabled, its value should be 0. This parameter is specified
74    * by the %[0-9]m specifier. For instance %2m enables merging using
75    * 2 profile data files. %1m is equivalent to %m. Also %m specifier
76    * can only appear once at the end of the name pattern. */
77   unsigned MergePoolSize;
78   ProfileNameSpecifier PNS;
79 } lprofFilename;
80 
81 lprofFilename lprofCurFilename = {0, {0}, {0}, 0, 0, 0, PNS_unknown};
82 
83 int getpid(void);
84 static int getCurFilenameLength();
85 static const char *getCurFilename(char *FilenameBuf);
doMerging()86 static unsigned doMerging() { return lprofCurFilename.MergePoolSize; }
87 
88 /* Return 1 if there is an error, otherwise return  0.  */
fileWriter(ProfDataIOVec * IOVecs,uint32_t NumIOVecs,void ** WriterCtx)89 static uint32_t fileWriter(ProfDataIOVec *IOVecs, uint32_t NumIOVecs,
90                            void **WriterCtx) {
91   uint32_t I;
92   FILE *File = (FILE *)*WriterCtx;
93   for (I = 0; I < NumIOVecs; I++) {
94     if (fwrite(IOVecs[I].Data, IOVecs[I].ElmSize, IOVecs[I].NumElm, File) !=
95         IOVecs[I].NumElm)
96       return 1;
97   }
98   return 0;
99 }
100 
101 COMPILER_RT_VISIBILITY ProfBufferIO *
lprofCreateBufferIOInternal(void * File,uint32_t BufferSz)102 lprofCreateBufferIOInternal(void *File, uint32_t BufferSz) {
103   FreeHook = &free;
104   DynamicBufferIOBuffer = (uint8_t *)calloc(BufferSz, 1);
105   VPBufferSize = BufferSz;
106   return lprofCreateBufferIO(fileWriter, File);
107 }
108 
setupIOBuffer()109 static void setupIOBuffer() {
110   const char *BufferSzStr = 0;
111   BufferSzStr = getenv("LLVM_VP_BUFFER_SIZE");
112   if (BufferSzStr && BufferSzStr[0]) {
113     VPBufferSize = atoi(BufferSzStr);
114     DynamicBufferIOBuffer = (uint8_t *)calloc(VPBufferSize, 1);
115   }
116 }
117 
118 /* Read profile data in \c ProfileFile and merge with in-memory
119    profile counters. Returns -1 if there is fatal error, otheriwse
120    0 is returned.
121 */
doProfileMerging(FILE * ProfileFile)122 static int doProfileMerging(FILE *ProfileFile) {
123   uint64_t ProfileFileSize;
124   char *ProfileBuffer;
125 
126   if (fseek(ProfileFile, 0L, SEEK_END) == -1) {
127     PROF_ERR("Unable to merge profile data, unable to get size: %s\n",
128              strerror(errno));
129     return -1;
130   }
131   ProfileFileSize = ftell(ProfileFile);
132 
133   /* Restore file offset.  */
134   if (fseek(ProfileFile, 0L, SEEK_SET) == -1) {
135     PROF_ERR("Unable to merge profile data, unable to rewind: %s\n",
136              strerror(errno));
137     return -1;
138   }
139 
140   /* Nothing to merge.  */
141   if (ProfileFileSize < sizeof(__llvm_profile_header)) {
142     if (ProfileFileSize)
143       PROF_WARN("Unable to merge profile data: %s\n",
144                 "source profile file is too small.");
145     return 0;
146   }
147 
148   ProfileBuffer = mmap(NULL, ProfileFileSize, PROT_READ, MAP_SHARED | MAP_FILE,
149                        fileno(ProfileFile), 0);
150   if (ProfileBuffer == MAP_FAILED) {
151     PROF_ERR("Unable to merge profile data, mmap failed: %s\n",
152              strerror(errno));
153     return -1;
154   }
155 
156   if (__llvm_profile_check_compatibility(ProfileBuffer, ProfileFileSize)) {
157     (void)munmap(ProfileBuffer, ProfileFileSize);
158     PROF_WARN("Unable to merge profile data: %s\n",
159               "source profile file is not compatible.");
160     return 0;
161   }
162 
163   /* Now start merging */
164   __llvm_profile_merge_from_buffer(ProfileBuffer, ProfileFileSize);
165   (void)munmap(ProfileBuffer, ProfileFileSize);
166 
167   return 0;
168 }
169 
170 /* Open the profile data for merging. It opens the file in r+b mode with
171  * file locking.  If the file has content which is compatible with the
172  * current process, it also reads in the profile data in the file and merge
173  * it with in-memory counters. After the profile data is merged in memory,
174  * the original profile data is truncated and gets ready for the profile
175  * dumper. With profile merging enabled, each executable as well as any of
176  * its instrumented shared libraries dump profile data into their own data file.
177 */
openFileForMerging(const char * ProfileFileName)178 static FILE *openFileForMerging(const char *ProfileFileName) {
179   FILE *ProfileFile;
180   int rc;
181 
182   ProfileFile = lprofOpenFileEx(ProfileFileName);
183   if (!ProfileFile)
184     return NULL;
185 
186   rc = doProfileMerging(ProfileFile);
187   if (rc || COMPILER_RT_FTRUNCATE(ProfileFile, 0L) ||
188       fseek(ProfileFile, 0L, SEEK_SET) == -1) {
189     PROF_ERR("Profile Merging of file %s failed: %s\n", ProfileFileName,
190              strerror(errno));
191     fclose(ProfileFile);
192     return NULL;
193   }
194   fseek(ProfileFile, 0L, SEEK_SET);
195   return ProfileFile;
196 }
197 
198 /* Write profile data to file \c OutputName.  */
writeFile(const char * OutputName)199 static int writeFile(const char *OutputName) {
200   int RetVal;
201   FILE *OutputFile;
202 
203   if (!doMerging())
204     OutputFile = fopen(OutputName, "ab");
205   else
206     OutputFile = openFileForMerging(OutputName);
207 
208   if (!OutputFile)
209     return -1;
210 
211   FreeHook = &free;
212   setupIOBuffer();
213   RetVal = lprofWriteData(fileWriter, OutputFile, lprofGetVPDataReader());
214 
215   fclose(OutputFile);
216   return RetVal;
217 }
218 
truncateCurrentFile(void)219 static void truncateCurrentFile(void) {
220   const char *Filename;
221   char *FilenameBuf;
222   FILE *File;
223   int Length;
224 
225   Length = getCurFilenameLength();
226   FilenameBuf = (char *)COMPILER_RT_ALLOCA(Length + 1);
227   Filename = getCurFilename(FilenameBuf);
228   if (!Filename)
229     return;
230 
231   /* Create the directory holding the file, if needed. */
232   if (strchr(Filename, '/') || strchr(Filename, '\\')) {
233     char *Copy = (char *)COMPILER_RT_ALLOCA(Length + 1);
234     strncpy(Copy, Filename, Length + 1);
235     __llvm_profile_recursive_mkdir(Copy);
236   }
237 
238   /* Truncate the file.  Later we'll reopen and append. */
239   File = fopen(Filename, "w");
240   if (!File)
241     return;
242   fclose(File);
243 }
244 
245 static const char *DefaultProfileName = "default.profraw";
resetFilenameToDefault(void)246 static void resetFilenameToDefault(void) {
247   memset(&lprofCurFilename, 0, sizeof(lprofCurFilename));
248   lprofCurFilename.FilenamePat = DefaultProfileName;
249   lprofCurFilename.PNS = PNS_default;
250 }
251 
containsMergeSpecifier(const char * FilenamePat,int I)252 static int containsMergeSpecifier(const char *FilenamePat, int I) {
253   return (FilenamePat[I] == 'm' ||
254           (FilenamePat[I] >= '1' && FilenamePat[I] <= '9' &&
255            /* If FilenamePat[I] is not '\0', the next byte is guaranteed
256             * to be in-bound as the string is null terminated. */
257            FilenamePat[I + 1] == 'm'));
258 }
259 
260 /* Parses the pattern string \p FilenamePat and stores the result to
261  * lprofcurFilename structure. */
parseFilenamePattern(const char * FilenamePat)262 static int parseFilenamePattern(const char *FilenamePat) {
263   int NumPids = 0, NumHosts = 0, I;
264   char *PidChars = &lprofCurFilename.PidChars[0];
265   char *Hostname = &lprofCurFilename.Hostname[0];
266   int MergingEnabled = 0;
267 
268   lprofCurFilename.FilenamePat = FilenamePat;
269   /* Check the filename for "%p", which indicates a pid-substitution. */
270   for (I = 0; FilenamePat[I]; ++I)
271     if (FilenamePat[I] == '%') {
272       if (FilenamePat[++I] == 'p') {
273         if (!NumPids++) {
274           if (snprintf(PidChars, MAX_PID_SIZE, "%d", getpid()) <= 0) {
275             PROF_WARN(
276                 "Unable to parse filename pattern %s. Using the default name.",
277                 FilenamePat);
278             return -1;
279           }
280         }
281       } else if (FilenamePat[I] == 'h') {
282         if (!NumHosts++)
283           if (COMPILER_RT_GETHOSTNAME(Hostname, COMPILER_RT_MAX_HOSTLEN)) {
284             PROF_WARN(
285                 "Unable to parse filename pattern %s. Using the default name.",
286                 FilenamePat);
287             return -1;
288           }
289       } else if (containsMergeSpecifier(FilenamePat, I)) {
290         if (MergingEnabled) {
291           PROF_WARN("%%m specifier can only be specified once in %s.\n",
292                     FilenamePat);
293           return -1;
294         }
295         MergingEnabled = 1;
296         if (FilenamePat[I] == 'm')
297           lprofCurFilename.MergePoolSize = 1;
298         else {
299           lprofCurFilename.MergePoolSize = FilenamePat[I] - '0';
300           I++; /* advance to 'm' */
301         }
302       }
303     }
304 
305   lprofCurFilename.NumPids = NumPids;
306   lprofCurFilename.NumHosts = NumHosts;
307   return 0;
308 }
309 
parseAndSetFilename(const char * FilenamePat,ProfileNameSpecifier PNS)310 static void parseAndSetFilename(const char *FilenamePat,
311                                 ProfileNameSpecifier PNS) {
312 
313   const char *OldFilenamePat = lprofCurFilename.FilenamePat;
314   ProfileNameSpecifier OldPNS = lprofCurFilename.PNS;
315 
316   if (PNS < OldPNS)
317     return;
318 
319   if (!FilenamePat)
320     FilenamePat = DefaultProfileName;
321 
322   /* When -fprofile-instr-generate=<path> is specified on the
323    * command line, each module will be instrumented with runtime
324    * init call to __llvm_profile_init function which calls
325    * __llvm_profile_override_default_filename. In most of the cases,
326    * the path will be identical, so bypass the parsing completely.
327    */
328   if (OldFilenamePat && !strcmp(OldFilenamePat, FilenamePat)) {
329     lprofCurFilename.PNS = PNS;
330     return;
331   }
332 
333   /* When PNS >= OldPNS, the last one wins. */
334   if (!FilenamePat || parseFilenamePattern(FilenamePat))
335     resetFilenameToDefault();
336   lprofCurFilename.PNS = PNS;
337 
338   if (!OldFilenamePat) {
339     PROF_NOTE("Set profile file path to \"%s\" via %s.\n",
340               lprofCurFilename.FilenamePat, getPNSStr(PNS));
341   } else {
342     PROF_NOTE("Override old profile path \"%s\" via %s to \"%s\" via %s.\n",
343               OldFilenamePat, getPNSStr(OldPNS), lprofCurFilename.FilenamePat,
344               getPNSStr(PNS));
345   }
346 
347   if (!lprofCurFilename.MergePoolSize)
348     truncateCurrentFile();
349 }
350 
351 /* Return buffer length that is required to store the current profile
352  * filename with PID and hostname substitutions. */
353 /* The length to hold uint64_t followed by 2 digit pool id including '_' */
354 #define SIGLEN 24
getCurFilenameLength()355 static int getCurFilenameLength() {
356   int Len;
357   if (!lprofCurFilename.FilenamePat || !lprofCurFilename.FilenamePat[0])
358     return 0;
359 
360   if (!(lprofCurFilename.NumPids || lprofCurFilename.NumHosts ||
361         lprofCurFilename.MergePoolSize))
362     return strlen(lprofCurFilename.FilenamePat);
363 
364   Len = strlen(lprofCurFilename.FilenamePat) +
365         lprofCurFilename.NumPids * (strlen(lprofCurFilename.PidChars) - 2) +
366         lprofCurFilename.NumHosts * (strlen(lprofCurFilename.Hostname) - 2);
367   if (lprofCurFilename.MergePoolSize)
368     Len += SIGLEN;
369   return Len;
370 }
371 
372 /* Return the pointer to the current profile file name (after substituting
373  * PIDs and Hostnames in filename pattern. \p FilenameBuf is the buffer
374  * to store the resulting filename. If no substitution is needed, the
375  * current filename pattern string is directly returned. */
getCurFilename(char * FilenameBuf)376 static const char *getCurFilename(char *FilenameBuf) {
377   int I, J, PidLength, HostNameLength;
378   const char *FilenamePat = lprofCurFilename.FilenamePat;
379 
380   if (!lprofCurFilename.FilenamePat || !lprofCurFilename.FilenamePat[0])
381     return 0;
382 
383   if (!(lprofCurFilename.NumPids || lprofCurFilename.NumHosts ||
384         lprofCurFilename.MergePoolSize))
385     return lprofCurFilename.FilenamePat;
386 
387   PidLength = strlen(lprofCurFilename.PidChars);
388   HostNameLength = strlen(lprofCurFilename.Hostname);
389   /* Construct the new filename. */
390   for (I = 0, J = 0; FilenamePat[I]; ++I)
391     if (FilenamePat[I] == '%') {
392       if (FilenamePat[++I] == 'p') {
393         memcpy(FilenameBuf + J, lprofCurFilename.PidChars, PidLength);
394         J += PidLength;
395       } else if (FilenamePat[I] == 'h') {
396         memcpy(FilenameBuf + J, lprofCurFilename.Hostname, HostNameLength);
397         J += HostNameLength;
398       } else if (containsMergeSpecifier(FilenamePat, I)) {
399         char LoadModuleSignature[SIGLEN];
400         int S;
401         int ProfilePoolId = getpid() % lprofCurFilename.MergePoolSize;
402         S = snprintf(LoadModuleSignature, SIGLEN, "%" PRIu64 "_%d",
403                      lprofGetLoadModuleSignature(), ProfilePoolId);
404         if (S == -1 || S > SIGLEN)
405           S = SIGLEN;
406         memcpy(FilenameBuf + J, LoadModuleSignature, S);
407         J += S;
408         if (FilenamePat[I] != 'm')
409           I++;
410       }
411       /* Drop any unknown substitutions. */
412     } else
413       FilenameBuf[J++] = FilenamePat[I];
414   FilenameBuf[J] = 0;
415 
416   return FilenameBuf;
417 }
418 
419 /* Returns the pointer to the environment variable
420  * string. Returns null if the env var is not set. */
getFilenamePatFromEnv(void)421 static const char *getFilenamePatFromEnv(void) {
422   const char *Filename = getenv("LLVM_PROFILE_FILE");
423   if (!Filename || !Filename[0])
424     return 0;
425   return Filename;
426 }
427 
428 /* This method is invoked by the runtime initialization hook
429  * InstrProfilingRuntime.o if it is linked in. Both user specified
430  * profile path via -fprofile-instr-generate= and LLVM_PROFILE_FILE
431  * environment variable can override this default value. */
432 COMPILER_RT_VISIBILITY
__llvm_profile_initialize_file(void)433 void __llvm_profile_initialize_file(void) {
434   const char *FilenamePat;
435 
436   FilenamePat = getFilenamePatFromEnv();
437   parseAndSetFilename(FilenamePat, FilenamePat ? PNS_environment : PNS_default);
438 }
439 
440 /* This API is directly called by the user application code. It has the
441  * highest precedence compared with LLVM_PROFILE_FILE environment variable
442  * and command line option -fprofile-instr-generate=<profile_name>.
443  */
444 COMPILER_RT_VISIBILITY
__llvm_profile_set_filename(const char * FilenamePat)445 void __llvm_profile_set_filename(const char *FilenamePat) {
446   parseAndSetFilename(FilenamePat, PNS_runtime_api);
447 }
448 
449 /*
450  * This API is invoked by the global initializers emitted by Clang/LLVM when
451  * -fprofile-instr-generate=<..> is specified (vs -fprofile-instr-generate
452  *  without an argument). This option has lower precedence than the
453  *  LLVM_PROFILE_FILE environment variable.
454  */
455 COMPILER_RT_VISIBILITY
__llvm_profile_override_default_filename(const char * FilenamePat)456 void __llvm_profile_override_default_filename(const char *FilenamePat) {
457   parseAndSetFilename(FilenamePat, PNS_command_line);
458 }
459 
460 /* The public API for writing profile data into the file with name
461  * set by previous calls to __llvm_profile_set_filename or
462  * __llvm_profile_override_default_filename or
463  * __llvm_profile_initialize_file. */
464 COMPILER_RT_VISIBILITY
__llvm_profile_write_file(void)465 int __llvm_profile_write_file(void) {
466   int rc, Length;
467   const char *Filename;
468   char *FilenameBuf;
469 
470   Length = getCurFilenameLength();
471   FilenameBuf = (char *)COMPILER_RT_ALLOCA(Length + 1);
472   Filename = getCurFilename(FilenameBuf);
473 
474   /* Check the filename. */
475   if (!Filename) {
476     PROF_ERR("Failed to write file : %s\n", "Filename not set");
477     return -1;
478   }
479 
480   /* Check if there is llvm/runtime version mismatch.  */
481   if (GET_VERSION(__llvm_profile_get_version()) != INSTR_PROF_RAW_VERSION) {
482     PROF_ERR("Runtime and instrumentation version mismatch : "
483              "expected %d, but get %d\n",
484              INSTR_PROF_RAW_VERSION,
485              (int)GET_VERSION(__llvm_profile_get_version()));
486     return -1;
487   }
488 
489   /* Write profile data to the file. */
490   rc = writeFile(Filename);
491   if (rc)
492     PROF_ERR("Failed to write file \"%s\": %s\n", Filename, strerror(errno));
493   return rc;
494 }
495 
writeFileWithoutReturn(void)496 static void writeFileWithoutReturn(void) { __llvm_profile_write_file(); }
497 
498 COMPILER_RT_VISIBILITY
__llvm_profile_register_write_file_atexit(void)499 int __llvm_profile_register_write_file_atexit(void) {
500   static int HasBeenRegistered = 0;
501 
502   if (HasBeenRegistered)
503     return 0;
504 
505   lprofSetupValueProfiler();
506 
507   HasBeenRegistered = 1;
508   return atexit(writeFileWithoutReturn);
509 }
510