ELF: Change FileSize back to a uint64_t.

[pcc]

Summary

This lets us detect file size overflows when creating a 64-bit binary on
a 32-bit machine.

[ruiu]

LGTM

lld/ELF/Writer.cpp

private:
   std::unique_ptr<FileOutputBuffer> &Buffer;
 
   void addRelIpltSymbols();
   void addStartEndSymbols();
   void addStartStopSymbols(OutputSection *Sec);
 
   std::vector<PhdrEntry *> Phdrs;
 
-  size_t FileSize;
+  uint64_t FileSize;
   uint64_t SectionHeaderOff;
 };
 } // anonymous namespace
 
 static bool isSectionPrefix(StringRef Prefix, StringRef Name) {
   return Name.startswith(Prefix) || Name == Prefix.drop_back();
 }
 
template <class ELFT> void Writer<ELFT>::writeHeader() {
 
   for (OutputSection *Sec : OutputSections)
     Sec->writeHeaderTo<ELFT>(++SHdrs);
 }
 
 // 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;
   }
 
   unlinkAsync(Config->OutputFile);
   unsigned Flags = 0;
   if (!Config->Relocatable)
     Flags = FileOutputBuffer::F_executable;
if (Sec->Type != SHT_REL && Sec->Type != SHT_RELA)
       Sec->writeTo<ELFT>(Out::BufferStart + Sec->Offset);
 }
 
 template <class ELFT> void Writer<ELFT>::writeBuildId() {
   if (!In.BuildId || !In.BuildId->getParent())
     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>();
 template void elf::writeResult<ELF32BE>();
 template void elf::writeResult<ELF64LE>();
 template void elf::writeResult<ELF64BE>();

lld/test/ELF/linkerscript/output-too-large-32bit.s

+# 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

lld/test/lit.cfg.py

if (lit.util.which('cvtres', config.environment['PATH']) or
     config.available_features.add('manifest_tool')
 
 if config.llvm_libxml2_enabled:
     config.available_features.add('libxml2')
 
 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(
         [tar_executable, '--version'],
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
         env={'LANG': 'C'})
     sout, _ = tar_version.communicate()
     if 'GNU tar' in sout.decode():
         config.available_features.add('gnutar')

lld/test/lit.site.cfg.py.in

 config.llvm_libxml2_enabled = @LLVM_LIBXML2_ENABLED@
 config.lit_tools_dir = "@LLVM_LIT_TOOLS_DIR@"
 config.lld_obj_root = "@LLD_BINARY_DIR@"
 config.lld_libs_dir = "@LLVM_LIBRARY_OUTPUT_INTDIR@"
 config.lld_tools_dir = "@LLVM_RUNTIME_OUTPUT_INTDIR@"
 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.
 try:
     config.llvm_tools_dir = config.llvm_tools_dir % lit_config.params
     config.llvm_libs_dir = config.llvm_libs_dir % lit_config.params
 except KeyError as e:
     key, = e.args
     lit_config.fatal("unable to find %r parameter, use '--param=%s=VALUE'" % (key,key))
 
 import lit.llvm
 lit.llvm.initialize(lit_config, config)
 
 # Let the main config do the real work.
 lit_config.load_config(config, "@LLD_SOURCE_DIR@/test/lit.cfg.py")

llvm/utils/gn/secondary/lld/test/BUILD.gn

if (llvm_enable_libxml2) {
     extra_values += [ "LLVM_LIBXML2_ENABLED=0" ]  # Must be 0.
   }
 
   if (llvm_enable_zlib) {
     extra_values += [ "HAVE_LIBZ=1" ]
   } 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") {
   # Fully-qualified instead of relative for LIT_SITE_CFG_IN_HEADER.
   input = "//lld/test/Unit/lit.site.cfg.py.in"
   output = lld_lit_unit_site_cfg_file
   extra_values = [ "LLVM_BUILD_MODE=." ]
 }