cmake: Enable 64bit off_t on 32bit glibc systems

[MaskRay]

Summary

Pass -D_FILE_OFFSET_BITS=64 to compiler flags on 32bit glibc based
systems. This will make sure that 64bit versions of LFS functions are
used e.g. seek will behave same as lseek64. Also revert [1] partially
because this added a cmake test to detect lseek64 but then forgot to
pass the needed macro to actual compile, this test was incomplete too
since libc implementations like musl has 64bit off_t by default on 32bit
systems and does not bundle[2] -D_LARGEFILE64_SOURCE under -D_GNU_SOURCE
like glibc, which means the compile now fails on musl because the cmake
check passes but we do not have _LARGEFILE64_SOURCE defined. Using the
*64 function was transitional anyways so use -D_FILE_OFFSET_BITS=64
instead

[1] https://github.com/llvm/llvm-project/commit/8db7e5e4eed4c4e697dc3164f2c9351d8c3e942b
[2] https://git.musl-libc.org/cgit/musl/commit/?id=25e6fee27f4a293728dd15b659170e7b9c7db9bc

[MaskRay]

include gn and bazel changes

[MaskRay]

Obsoleted by 5cd554303ead0f8891eee3cd6d25cb07f5a7bf67

llvm/cmake/config-ix.cmake

 check_symbol_exists(futimes sys/time.h HAVE_FUTIMES)
 # AddressSanitizer conflicts with lib/Support/Unix/Signals.inc
 # Avoid sigaltstack on Apple platforms, where backtrace() cannot handle it
 # (rdar://7089625) and _Unwind_Backtrace is unusable because it cannot unwind
 # past the signal handler after an assertion failure (rdar://29866587).
 if( HAVE_SIGNAL_H AND NOT LLVM_USE_SANITIZER MATCHES ".*Address.*" AND NOT APPLE )
   check_symbol_exists(sigaltstack signal.h HAVE_SIGALTSTACK)
 endif()
-set(CMAKE_REQUIRED_DEFINITIONS "-D_LARGEFILE64_SOURCE")
-check_symbol_exists(lseek64 "sys/types.h;unistd.h" HAVE_LSEEK64)
-set(CMAKE_REQUIRED_DEFINITIONS "")
 check_symbol_exists(mallctl malloc_np.h HAVE_MALLCTL)
 check_symbol_exists(mallinfo malloc.h HAVE_MALLINFO)
 check_symbol_exists(mallinfo2 malloc.h HAVE_MALLINFO2)
 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)
else()
   CHECK_STRUCT_HAS_MEMBER("struct stat" st_mtim.tv_nsec
       "sys/types.h;sys/stat.h" HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC)
 endif()
 
 check_symbol_exists(__GLIBC__ stdio.h LLVM_USING_GLIBC)
 if( LLVM_USING_GLIBC )
   add_compile_definitions(_GNU_SOURCE)
   list(APPEND CMAKE_REQUIRED_DEFINITIONS "-D_GNU_SOURCE")
+# enable 64bit off_t on 32bit systems using glibc
+  if (CMAKE_SIZEOF_VOID_P EQUAL 4)
+    add_compile_definitions(_FILE_OFFSET_BITS=64)
+    list(APPEND CMAKE_REQUIRED_DEFINITIONS "-D_FILE_OFFSET_BITS=64")
+  endif()
 endif()
 
 # This check requires _GNU_SOURCE.
 if (NOT PURE_WINDOWS)
   if (LLVM_PTHREAD_LIB)
     list(APPEND CMAKE_REQUIRED_LIBRARIES ${LLVM_PTHREAD_LIB})
   endif()
   check_symbol_exists(pthread_getname_np pthread.h HAVE_PTHREAD_GETNAME_NP)

llvm/include/llvm/Config/config.h.cmake

 #cmakedefine HAVE_PTHREAD_GETNAME_NP ${HAVE_PTHREAD_GETNAME_NP}
 
 /* Define to 1 if you have the `pthread_setname_np' function. */
 #cmakedefine HAVE_PTHREAD_SETNAME_NP ${HAVE_PTHREAD_SETNAME_NP}
 
 /* Define to 1 if you have the <link.h> header file. */
 #cmakedefine HAVE_LINK_H ${HAVE_LINK_H}
 
-/* Define to 1 if you have the `lseek64' function. */
-#cmakedefine HAVE_LSEEK64 ${HAVE_LSEEK64}
-
 /* Define to 1 if you have the <mach/mach.h> header file. */
 #cmakedefine HAVE_MACH_MACH_H ${HAVE_MACH_MACH_H}
 
 /* Define to 1 if you have the `mallctl' function. */
 #cmakedefine HAVE_MALLCTL ${HAVE_MALLCTL}
 
 /* Define to 1 if you have the `mallinfo' function. */
 #cmakedefine HAVE_MALLINFO ${HAVE_MALLINFO}

llvm/lib/Support/raw_ostream.cpp

void raw_fd_ostream::close() {
   FD = -1;
 }
 
 uint64_t raw_fd_ostream::seek(uint64_t off) {
   assert(SupportsSeeking && "Stream does not support seeking!");
   flush();
 #ifdef _WIN32
   pos = ::_lseeki64(FD, off, SEEK_SET);
-#elif defined(HAVE_LSEEK64)
-  pos = ::lseek64(FD, off, SEEK_SET);
 #else
   pos = ::lseek(FD, off, SEEK_SET);
 #endif
   if (pos == (uint64_t)-1)
     error_detected(std::error_code(errno, std::generic_category()));
   return pos;
 }
 

llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn

values = [
     # FIXME: Set to 1 on mac once the 10.14 SDK is in common use.
     "LLVM_SUPPORT_XCODE_SIGNPOSTS=",
   ]
 
   if (current_os == "linux" || current_os == "android") {
     values += [
       "HAVE_FUTIMENS=1",
       "HAVE_LINK_H=1",
-      "HAVE_LSEEK64=1",
       "HAVE_MALLINFO=1",
       "HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC=1",
     ]
   } else {
     values += [
       "HAVE_FUTIMENS=",
       "HAVE_LINK_H=",
-      "HAVE_LSEEK64=",
       "HAVE_MALLINFO=",
       "HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC=",
     ]
   }
 
   if (current_os == "mac") {
     values += [
       "HAVE_CRASHREPORTER_INFO=1",

utils/bazel/llvm_configs/config.h.cmake

 #cmakedefine HAVE_PTHREAD_GETNAME_NP ${HAVE_PTHREAD_GETNAME_NP}
 
 /* Define to 1 if you have the `pthread_setname_np' function. */
 #cmakedefine HAVE_PTHREAD_SETNAME_NP ${HAVE_PTHREAD_SETNAME_NP}
 
 /* Define to 1 if you have the <link.h> header file. */
 #cmakedefine HAVE_LINK_H ${HAVE_LINK_H}
 
-/* Define to 1 if you have the `lseek64' function. */
-#cmakedefine HAVE_LSEEK64 ${HAVE_LSEEK64}
-
 /* Define to 1 if you have the <mach/mach.h> header file. */
 #cmakedefine HAVE_MACH_MACH_H ${HAVE_MACH_MACH_H}
 
 /* Define to 1 if you have the `mallctl' function. */
 #cmakedefine HAVE_MALLCTL ${HAVE_MALLCTL}
 
 /* Define to 1 if you have the `mallinfo' function. */
 #cmakedefine HAVE_MALLINFO ${HAVE_MALLINFO}