Use sys::fs::real_path() instead of realpath() in Symbolize and remove HAVE_REALPATH.

[thakis]

Summary

No intended behavior change.

[thakis]

kcc, if samsonov no longer does llvm reviews, who can review this?

[hans]

lib/DebugInfo/Symbolize/Symbolize.cpp

173

Yes, seems to be missing a not operator. I find std::error_code confusing.

[samsonov]

Looks like this code has been removed in https://reviews.llvm.org/D57609, but I'm not sure the removal is correct (added a comment in that thread).

[thakis]

Made obsolete by D57609

cmake/config-ix.cmake

 set(CMAKE_REQUIRED_DEFINITIONS "")
 check_symbol_exists(mallctl malloc_np.h HAVE_MALLCTL)
 check_symbol_exists(mallinfo malloc.h HAVE_MALLINFO)
 check_symbol_exists(malloc_zone_statistics malloc/malloc.h
                     HAVE_MALLOC_ZONE_STATISTICS)
 check_symbol_exists(getrlimit "sys/types.h;sys/time.h;sys/resource.h" HAVE_GETRLIMIT)
 check_symbol_exists(posix_spawn spawn.h HAVE_POSIX_SPAWN)
 check_symbol_exists(pread unistd.h HAVE_PREAD)
-check_symbol_exists(realpath stdlib.h HAVE_REALPATH)
 check_symbol_exists(sbrk unistd.h HAVE_SBRK)
 check_symbol_exists(strerror string.h HAVE_STRERROR)
 check_symbol_exists(strerror_r string.h HAVE_STRERROR_R)
 check_symbol_exists(strerror_s string.h HAVE_DECL_STRERROR_S)
 check_symbol_exists(setenv stdlib.h HAVE_SETENV)
 if( PURE_WINDOWS )
   check_symbol_exists(_chsize_s io.h HAVE__CHSIZE_S)
 

include/llvm/Config/config.h.cmake

 #cmakedefine HAVE_PTHREAD_H ${HAVE_PTHREAD_H}
 
 /* Have pthread_mutex_lock */
 #cmakedefine HAVE_PTHREAD_MUTEX_LOCK ${HAVE_PTHREAD_MUTEX_LOCK}
 
 /* Have pthread_rwlock_init */
 #cmakedefine HAVE_PTHREAD_RWLOCK_INIT ${HAVE_PTHREAD_RWLOCK_INIT}
 
-/* Define to 1 if you have the `realpath' function. */
-#cmakedefine HAVE_REALPATH ${HAVE_REALPATH}
-
 /* Define to 1 if you have the `sbrk' function. */
 #cmakedefine HAVE_SBRK ${HAVE_SBRK}
 
 /* Define to 1 if you have the `setenv' function. */
 #cmakedefine HAVE_SETENV ${HAVE_SETENV}
 
 /* Define to 1 if you have the `sched_getaffinity' function. */
 #cmakedefine HAVE_SCHED_GETAFFINITY ${HAVE_SCHED_GETAFFINITY}

lib/DebugInfo/Symbolize/Symbolize.cpp

bool checkFileCRC(StringRef Path, uint32_t CRCHash) {
   if (!MB)
     return false;
   return !zlib::isAvailable() || CRCHash == zlib::crc32(MB.get()->getBuffer());
 }
 
 bool findDebugBinary(const std::string &OrigPath,
                      const std::string &DebuglinkName, uint32_t CRCHash,
                      std::string &Result) {
-  std::string OrigRealPath = OrigPath;
-#if defined(HAVE_REALPATH)
-  if (char *RP = realpath(OrigPath.c_str(), nullptr)) {
-    OrigRealPath = RP;
-    free(RP);
-  }
-#endif
+  SmallString<256> OrigRealPath;
+  if (sys::fs::real_path(OrigPath, OrigRealPath))
+    OrigRealPath = OrigPath;
   SmallString<16> OrigDir(OrigRealPath);
   llvm::sys::path::remove_filename(OrigDir);
   SmallString<16> DebugPath = OrigDir;
   // Try /path/to/original_binary/debuglink_name
   llvm::sys::path::append(DebugPath, DebuglinkName);
   if (checkFileCRC(DebugPath, CRCHash)) {
     Result = DebugPath.str();
     return true;