Fix unsafe memory access.

[ruiu]

Summary

Fix unsafe memory access.

[ruiu]

• update

[filcab]

This does fix PR26908.
Please mention the bug in the commit message (you might want to mention it was a use-after-free problem too).

[ruiu]

This patch was just to demonstrate what I want to see so it lacked a commit
message. However, if you are okay with this, I'll write a description for
it and submit.

[filcab]

LGTM. Thanks for improving it!

ELF/Driver.h

private:
 
   llvm::BumpPtrAllocator Alloc;
   bool WholeArchive = false;
   std::vector<std::unique_ptr<InputFile>> Files;
   std::vector<std::unique_ptr<MemoryBuffer>> OwningMBs;
 };
 
 // Parses command line options.
-llvm::opt::InputArgList parseArgs(llvm::BumpPtrAllocator *A,
-                                  ArrayRef<const char *> Args);
+class ELFOptTable : public llvm::opt::OptTable {
+public:
+  ELFOptTable();
+  llvm::opt::InputArgList parse(ArrayRef<const char *> Argv);
+
+private:
+  llvm::BumpPtrAllocator Alloc;
+};
 
 // 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) OPT_##ID,
 #include "Options.inc"
 #undef OPTION
 };

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) {
-  opt::InputArgList Args = parseArgs(&Alloc, ArgsArr.slice(1));
+  ELFOptTable Parser;
+  opt::InputArgList Args = Parser.parse(ArgsArr.slice(1));
   if (Args.hasArg(OPT_help)) {
     printHelp(ArgsArr[0]);
     return;
   }
   if (Args.hasArg(OPT_version)) {
     printVersion();
     return;
   }

ELF/DriverUtils.cpp

#define OPTION(X1, X2, ID, KIND, GROUP, ALIAS, X6, X7, X8, X9, X10)            \
     X1, X2, X9, X10, OPT_##ID, opt::Option::KIND##Class, X8, X7, OPT_##GROUP,  \
         OPT_##ALIAS, X6                                                        \
   }                                                                            \
   ,
 #include "Options.inc"
 #undef OPTION
 };
 
-class ELFOptTable : public opt::OptTable {
-public:
-  ELFOptTable() : OptTable(infoTable) {}
-};
+ELFOptTable::ELFOptTable() : OptTable(infoTable) {}
 
 // Parses a given list of options.
-opt::InputArgList elf::parseArgs(llvm::BumpPtrAllocator *A,
-                                 ArrayRef<const char *> Argv) {
+opt::InputArgList ELFOptTable::parse(ArrayRef<const char *> Argv) {
   // Make InputArgList from string vectors.
-  ELFOptTable Table;
   unsigned MissingIndex;
   unsigned MissingCount;
 
   // Expand response files. '@<filename>' is replaced by the file's contents.
   SmallVector<const char *, 256> Vec(Argv.data(), Argv.data() + Argv.size());
-  StringSaver Saver(*A);
+  StringSaver Saver(Alloc);
   llvm::cl::ExpandResponseFiles(Saver, llvm::cl::TokenizeGNUCommandLine, Vec);
 
   // Parse options and then do error checking.
-  opt::InputArgList Args = Table.ParseArgs(Vec, MissingIndex, MissingCount);
+  opt::InputArgList Args = this->ParseArgs(Vec, MissingIndex, MissingCount);
   if (MissingCount)
     error(Twine("missing arg value for \"") + Args.getArgString(MissingIndex) +
           "\", expected " + Twine(MissingCount) +
           (MissingCount == 1 ? " argument.\n" : " arguments"));
 
   iterator_range<opt::arg_iterator> Unknowns = Args.filtered(OPT_UNKNOWN);
   for (auto *Arg : Unknowns)
     warning("warning: unknown argument: " + Arg->getSpelling());