[ELF] - Do not call doInitSymbols for all ELFTs

[grimar]

Summary

It looks a bit wierd that we have to initialize symbols for all ELFT types when
we use only one ELFT for link. It is little but extra work. Do we really have reasons for that ?
I reviewed this symbols we are initializing and I think we can only init those
what we need at start of link() call.

[• rafael]

LGTM. As a followup patch, can you move doInitSymbols to Driver.cpp and make it static?

[grimar]

In D18047#371986, @rafael wrote:

LGTM. As a followup patch, can you move doInitSymbols to Driver.cpp and make it static?

Sure. Should this change also be reviewed or can I just commit it after this one ?

[grimar]

In D18047#371990, @grimar wrote:

In D18047#371986, @rafael wrote:

LGTM. As a followup patch, can you move doInitSymbols to Driver.cpp and make it static?

Sure. Should this change also be reviewed or can I just commit it after this one ?

I mean "followup" here is the same commit or separate one ?

[ruiu]

LGTM

ELF/Symbols.h

44

Rename doInitSymbols -> initSymbols. ("do" is a prefix I often add to file-local helper functions.)

[grimar]

In D18047#371986, @rafael wrote:

As a followup patch, can you move doInitSymbols to Driver.cpp and make it static?

Will do that tomorrow as well.

[ruiu]

Because that Symbol.cpp needs to initialize symbols for each ELF type is an internal detail of the file. initSymbol, or in general, init<filename> is the initializer function for a file.

ELF/Driver.cpp

 static bool hasZOption(opt::InputArgList &Args, StringRef Key) {
   for (auto *Arg : Args.filtered(OPT_z))
     if (Key == Arg->getValue())
       return true;
   return false;
 }
 
 void LinkerDriver::main(ArrayRef<const char *> ArgsArr) {
-  initSymbols();
-
   opt::InputArgList Args = parseArgs(&Alloc, ArgsArr.slice(1));
   if (Args.hasArg(OPT_help)) {
     printHelp(ArgsArr[0]);
     return;
   }
   if (Args.hasArg(OPT_version)) {
     printVersion();
     return;
for (auto *Arg : Args) {
     }
   }
 
   if (Files.empty() && !HasError)
     error("no input files.");
 }
 
 template <class ELFT> void LinkerDriver::link(opt::InputArgList &Args) {
+  doInitSymbols<ELFT>();
   // For LTO
   InitializeAllTargets();
   InitializeAllTargetMCs();
   InitializeAllAsmPrinters();
   InitializeAllAsmParsers();
 
   SymbolTable<ELFT> Symtab;
   std::unique_ptr<TargetInfo> TI(createTarget());

ELF/Symbols.h

 class InputFile;
 class SymbolBody;
 template <class ELFT> class ObjectFile;
 template <class ELFT> class OutputSection;
 template <class ELFT> class OutputSectionBase;
 template <class ELFT> class SharedFile;
 
 // Initializes global objects defined in this file.
-// Called at the beginning of main().
-void initSymbols();
+template <class ELFT> void doInitSymbols();
 
 // Returns a demangled C++ symbol name. If Name is not a mangled
 // name or the system does not provide __cxa_demangle function,
 // it returns the unmodified string.
 std::string demangle(StringRef Name);
 
 // A real symbol object, SymbolBody, is usually accessed indirectly
 // through a Symbol. There's always one Symbol for each symbol name.

ELF/Symbols.cpp

std::unique_ptr<InputFile> Lazy::getMember() {
 
   // getMember returns an empty buffer if the member was already
   // read from the library.
   if (MBRef.getBuffer().empty())
     return std::unique_ptr<InputFile>(nullptr);
   return createObjectFile(MBRef, File->getName());
 }
 
-template <class ELFT> static void doInitSymbols() {
+template <class ELFT> void elf::doInitSymbols() {
   ElfSym<ELFT>::Etext.setBinding(STB_GLOBAL);
   ElfSym<ELFT>::Edata.setBinding(STB_GLOBAL);
   ElfSym<ELFT>::End.setBinding(STB_GLOBAL);
   ElfSym<ELFT>::Ignored.setBinding(STB_WEAK);
   ElfSym<ELFT>::Ignored.setVisibility(STV_HIDDEN);
 }
 
-void elf::initSymbols() {
-  doInitSymbols<ELF32LE>();
-  doInitSymbols<ELF32BE>();
-  doInitSymbols<ELF64LE>();
-  doInitSymbols<ELF64BE>();
-}
-
 // Returns the demangled C++ symbol name for Name.
 std::string elf::demangle(StringRef Name) {
 #if !defined(HAVE_CXXABI_H)
   return Name;
 #else
   if (!Config->Demangle)
     return Name;
 

 template class elf::UndefinedElf<ELF32BE>;
 template class elf::UndefinedElf<ELF64LE>;
 template class elf::UndefinedElf<ELF64BE>;
 
 template class elf::DefinedSynthetic<ELF32LE>;
 template class elf::DefinedSynthetic<ELF32BE>;
 template class elf::DefinedSynthetic<ELF64LE>;
 template class elf::DefinedSynthetic<ELF64BE>;
+
+template void elf::doInitSymbols<ELF32LE>();
+template void elf::doInitSymbols<ELF32BE>();
+template void elf::doInitSymbols<ELF64LE>();
+template void elf::doInitSymbols<ELF64BE>();