Index: lld/trunk/ELF/Writer.cpp
===================================================================
--- lld/trunk/ELF/Writer.cpp
+++ lld/trunk/ELF/Writer.cpp
@@ -82,7 +82,7 @@
 
   std::vector<PhdrEntry *> Phdrs;
 
-  size_t FileSize;
+  uint64_t FileSize;
   uint64_t SectionHeaderOff;
 };
 } // anonymous namespace
@@ -2480,7 +2480,7 @@
 // Open a result file.
 template <class ELFT> void Writer<ELFT>::openFile() {
   uint64_t MaxSize = Config->Is64 ? INT64_MAX : UINT32_MAX;
-  if (MaxSize < FileSize) {
+  if (FileSize != size_t(FileSize) || MaxSize < FileSize) {
     error("output file too large: " + Twine(FileSize) + " bytes");
     return;
   }
@@ -2561,7 +2561,7 @@
     return;
 
   // Compute a hash of all sections of the output file.
-  In.BuildId->writeBuildId({Out::BufferStart, FileSize});
+  In.BuildId->writeBuildId({Out::BufferStart, size_t(FileSize)});
 }
 
 template void elf::writeResult<ELF32LE>();
Index: lld/trunk/test/ELF/linkerscript/output-too-large-32bit.s
===================================================================
--- lld/trunk/test/ELF/linkerscript/output-too-large-32bit.s
+++ lld/trunk/test/ELF/linkerscript/output-too-large-32bit.s
@@ -0,0 +1,11 @@
+# REQUIRES: x86 && !llvm-64-bits
+
+# RUN: llvm-mc -filetype=obj -triple=x86_64-unknown-linux %s -o %t.o
+# RUN: echo "SECTIONS { .text : { . = 0x6fffffffffffffff; *(.text*); } }" > %t.script
+# RUN: not ld.lld --no-check-sections --script %t.script %t.o -o /dev/null 2>&1 | FileCheck %s
+
+# CHECK: output file too large
+
+.global _start
+_start:
+  nop
Index: lld/trunk/test/lit.cfg.py
===================================================================
--- lld/trunk/test/lit.cfg.py
+++ lld/trunk/test/lit.cfg.py
@@ -97,6 +97,9 @@
 if config.have_dia_sdk:
     config.available_features.add("diasdk")
 
+if config.sizeof_void_p == 8:
+    config.available_features.add("llvm-64-bits")
+
 tar_executable = lit.util.which('tar', config.environment['PATH'])
 if tar_executable:
     tar_version = subprocess.Popen(
Index: lld/trunk/test/lit.site.cfg.py.in
===================================================================
--- lld/trunk/test/lit.site.cfg.py.in
+++ lld/trunk/test/lit.site.cfg.py.in
@@ -15,6 +15,7 @@
 config.target_triple = "@TARGET_TRIPLE@"
 config.python_executable = "@PYTHON_EXECUTABLE@"
 config.have_zlib = @HAVE_LIBZ@
+config.sizeof_void_p = @CMAKE_SIZEOF_VOID_P@
 
 # Support substitution of the tools and libs dirs with user parameters. This is
 # used when we can't determine the tool dir at configuration time.
Index: llvm/trunk/utils/gn/secondary/lld/test/BUILD.gn
===================================================================
--- llvm/trunk/utils/gn/secondary/lld/test/BUILD.gn
+++ llvm/trunk/utils/gn/secondary/lld/test/BUILD.gn
@@ -53,6 +53,12 @@
   } else {
     extra_values += [ "HAVE_LIBZ=0" ]  # Must be 0.
   }
+
+  if (current_cpu == "x64" || current_cpu == "arm64") {
+    extra_values += [ "CMAKE_SIZEOF_VOID_P=8" ]
+  } else {
+    extra_values += [ "CMAKE_SIZEOF_VOID_P=4" ]
+  }
 }
 
 write_lit_cfg("lit_unit_site_cfg") {