Store only argv[0] in Config

[• espindola]

Summary

Having it there seems in conflict with the desire to part all command
line options in the Driver.

[ruiu]

Actually I prefer making argv accessible globally just like the environment variable, perhaps due to the influence of Go in which command line arguments are accessible from anywhere as os.args. At least I think we want to keep Argv[0] globally accessible to produce error messages containing the command name.

[• espindola]

Having just the program name in Config might be the sweet spot. It is easy to access and we are sure that the rest of argv cannot be used outside of the driver.

[ruiu]

LGTM

ELF/Driver.cpp

88–93

Could you keep this at the beginning of the function? make shouldn't report an error, but it is easy to add more code before this code if we don't have this at the beginning.

[• espindola]

r324418

ELF/Config.h

struct Configuration {
   llvm::StringRef Emulation;
   llvm::StringRef Fini;
   llvm::StringRef Init;
   llvm::StringRef LTOAAPipeline;
   llvm::StringRef LTONewPmPasses;
   llvm::StringRef MapFile;
   llvm::StringRef OutputFile;
   llvm::StringRef OptRemarksFilename;
+  llvm::StringRef ProgName;
   llvm::StringRef SoName;
   llvm::StringRef Sysroot;
   llvm::StringRef ThinLTOCacheDir;
   std::string Rpath;
   std::vector<VersionDefinition> VersionDefinitions;
-  std::vector<llvm::StringRef> Argv;
   std::vector<llvm::StringRef> AuxiliaryList;
   std::vector<llvm::StringRef> FilterList;
   std::vector<llvm::StringRef> SearchPaths;
   std::vector<llvm::StringRef> SymbolOrderingFile;
   std::vector<llvm::StringRef> Undefined;
   std::vector<SymbolVersion> DynamicList;
   std::vector<SymbolVersion> VersionScriptGlobals;
   std::vector<SymbolVersion> VersionScriptLocals;

ELF/Driver.h

 // Create enum with OPT_xxx values for each option in Options.td
 enum {
   OPT_INVALID = 0,
 #define OPTION(_1, _2, ID, _4, _5, _6, _7, _8, _9, _10, _11, _12) OPT_##ID,
 #include "Options.inc"
 #undef OPTION
 };
 
-void printHelp(const char *Argv0);
+void printHelp();
 std::string createResponseFile(const llvm::opt::InputArgList &Args);
 
 llvm::Optional<std::string> findFromSearchPaths(StringRef Path);
 llvm::Optional<std::string> searchLinkerScript(StringRef Path);
 llvm::Optional<std::string> searchLibrary(StringRef Path);
 
 } // namespace elf
 } // namespace lld
 
 #endif

ELF/Driver.cpp

 
 Configuration *elf::Config;
 LinkerDriver *elf::Driver;
 
 static void setConfigs(opt::InputArgList &Args);
 
 bool elf::link(ArrayRef<const char *> Args, bool CanExitEarly,
                raw_ostream &Error) {
-  errorHandler().LogName = Args[0];
-  errorHandler().ErrorLimitExceededMsg =
-      "too many errors emitted, stopping now (use "
-      "-error-limit=0 to see all errors)";
-  errorHandler().ErrorOS = &Error;
-  errorHandler().ColorDiagnostics = Error.has_colors();
   InputSections.clear();
   OutputSections.clear();
   Tar = nullptr;
   BinaryFiles.clear();
   BitcodeFiles.clear();
   ObjectFiles.clear();
   SharedFiles.clear();
 
   Config = make<Configuration>();
   Driver = make<LinkerDriver>();
   Script = make<LinkerScript>();
   Symtab = make<SymbolTable>();
-  Config->Argv = {Args.begin(), Args.end()};
+  Config->ProgName = Args[0];
 
+  errorHandler().LogName = Config->ProgName;
+  errorHandler().ErrorLimitExceededMsg =
+      "too many errors emitted, stopping now (use "
+      "-error-limit=0 to see all errors)";
+  errorHandler().ErrorOS = &Error;
+  errorHandler().ColorDiagnostics = Error.has_colors();
   Driver->main(Args, CanExitEarly);
 
   // Exit immediately if we don't need to return to the caller.
   // This saves time because the overhead of calling destructors
   // for all globally-allocated objects is not negligible.
   if (Config->ExitEarly)
     exitLld(errorCount() ? 1 : 0);
 
void LinkerDriver::main(ArrayRef<const char *> ArgsArr, bool CanExitEarly) {
   ELFOptTable Parser;
   opt::InputArgList Args = Parser.parse(ArgsArr.slice(1));
 
   // Interpret this flag early because error() depends on them.
   errorHandler().ErrorLimit = args::getInteger(Args, OPT_error_limit, 20);
 
   // Handle -help
   if (Args.hasArg(OPT_help)) {
-    printHelp(ArgsArr[0]);
+    printHelp();
     return;
   }
 
   // Handle -v or -version.
   //
   // A note about "compatible with GNU linkers" message: this is a hack for
   // scripts generated by GNU Libtool 2.4.6 (released in February 2014 and
   // still the newest version in March 2017) or earlier to recognize LLD as
void LinkerDriver::readConfigs(opt::InputArgList &Args) {
   Config->ZRelro = !hasZOption(Args, "norelro");
   Config->ZRetpolineplt = hasZOption(Args, "retpolineplt");
   Config->ZRodynamic = hasZOption(Args, "rodynamic");
   Config->ZStackSize = args::getZOptionValue(Args, OPT_z, "stack-size", 0);
   Config->ZText = !hasZOption(Args, "notext");
   Config->ZWxneeded = hasZOption(Args, "wxneeded");
 
   // Parse LTO plugin-related options for compatibility with gold.
-  std::vector<const char *> LTOOptions({Config->Argv[0].data()});
+  std::vector<const char *> LTOOptions({Config->ProgName.data()});
   for (auto *Arg : Args.filtered(OPT_plugin_opt)) {
     StringRef S = Arg->getValue();
     if (S == "disable-verify")
       Config->DisableVerify = true;
     else if (S == "save-temps")
       Config->SaveTemps = true;
     else if (S.startswith("O"))
       Config->LTOO = parseInt(S.substr(1), Arg);

ELF/DriverUtils.cpp

opt::InputArgList ELFOptTable::parse(ArrayRef<const char *> Argv) {
   if (MissingCount)
     error(Twine(Args.getArgString(MissingIndex)) + ": missing argument");
 
   for (auto *Arg : Args.filtered(OPT_UNKNOWN))
     error("unknown argument: " + Arg->getSpelling());
   return Args;
 }
 
-void elf::printHelp(const char *Argv0) {
-  ELFOptTable().PrintHelp(outs(), Argv0, "lld", false /*ShowHidden*/,
-                          true /*ShowAllAliases*/);
+void elf::printHelp() {
+  ELFOptTable().PrintHelp(outs(), Config->ProgName.data(), "lld",
+                          false /*ShowHidden*/, true /*ShowAllAliases*/);
   outs() << "\n";
 
   // Scripts generated by Libtool versions up to at least 2.4.6 (the most
   // recent version as of March 2017) expect /: supported targets:.* elf/
   // in a message for the -help option. If it doesn't match, the scripts
   // assume that the linker doesn't support very basic features such as
   // shared libraries. Therefore, we need to print out at least "elf".
   // Here, we print out all the targets that we support.
-  outs() << Argv0 << ": supported targets: "
+  outs() << Config->ProgName << ": supported targets: "
          << "elf32-i386 elf32-iamcu elf32-littlearm elf32-ntradbigmips "
          << "elf32-ntradlittlemips elf32-powerpc elf32-tradbigmips "
          << "elf32-tradlittlemips elf32-x86-64 "
          << "elf64-amdgpu elf64-littleaarch64 elf64-powerpc elf64-tradbigmips "
          << "elf64-tradlittlemips elf64-x86-64\n";
 }
 
 // Reconstructs command line arguments so that so that you can re-run