Disable 64bit file position on old 32 bit Androids.

This is needed for building LLVM on Android with new NDK (newer
than r15c) and API level < 24. Android C library (Bionic) didn't have
support for 64 bit file position until Android N.

Differential Revision: https://reviews.llvm.org/D37314

llvm-svn: 312389

llvm/cmake/modules/HandleLLVMOptions.cmake

@@ -233,8 +233,12 @@ if( CMAKE_SIZEOF_VOID_P EQUAL 8 AND NOT WIN32 )
 endif( CMAKE_SIZEOF_VOID_P EQUAL 8 AND NOT WIN32 )
 
 # If building on a GNU specific 32-bit system, make sure off_t is 64 bits
-# so that off_t can stored offset > 2GB
-if( CMAKE_SIZEOF_VOID_P EQUAL 4 )
+# so that off_t can stored offset > 2GB.
+# Android until version N (API 24) doesn't support it.
+if (ANDROID AND (ANDROID_NATIVE_API_LEVEL LESS 24))
+  set(LLVM_FORCE_SMALLFILE_FOR_ANDROID TRUE)
+endif()
+if( CMAKE_SIZEOF_VOID_P EQUAL 4 AND NOT LLVM_FORCE_SMALLFILE_FOR_ANDROID)
   add_definitions( -D_LARGEFILE_SOURCE )
   add_definitions( -D_FILE_OFFSET_BITS=64 )
 endif()
@@ -303,13 +307,13 @@ if( MSVC )
     # especially so std::equal(nullptr, nullptr, nullptr) will not assert.
     add_definitions("-D_DEBUG_POINTER_IMPL=")
   endif()
-  
+
   include(ChooseMSVCCRT)
 
   if( MSVC11 )
     add_definitions(-D_VARIADIC_MAX=10)
   endif()
-  
+
   # Add definitions that make MSVC much less annoying.
   add_definitions(
     # For some reason MS wants to deprecate a bunch of standard functions...
@@ -370,7 +374,7 @@ if( MSVC )
 
       string(FIND "${upper_exe_flags} ${upper_module_flags} ${upper_shared_flags}"
         "/INCREMENTAL" linker_flag_idx)
-      
+
       if (${linker_flag_idx} GREATER -1)
         message(WARNING "/Brepro not compatible with /INCREMENTAL linking - builds will be non-deterministic")
       else()