[ELF] - Linkerscript: remove excessive ScriptConfiguration::Filler field

[grimar]

Summary

Previously OutputSectionCommand::Filler was introduced, but unused.
Patch fixes that.

[davide]

LGTM

LinkerScript.h

struct PhdrsCommand {
   bool HasPhdrs;
 };
 
 // ScriptConfiguration holds linker script parse results.
 struct ScriptConfiguration {
   // SECTIONS commands.
   std::vector<SectionRule> Sections;
 
-  // Section fill attribute for each section.
-  llvm::StringMap<std::vector<uint8_t>> Filler;
-
   // Used to assign addresses to sections.
   std::vector<std::unique_ptr<BaseCommand>> Commands;
 
   // Used to assign sections to headers.
   std::vector<PhdrsCommand> PhdrsCommands;
 
   bool DoLayout = false;
 

LinkerScript.cpp

for (OutputSectionBase<ELFT> *Sec : Sections) {
     if (NoteNum != -1 && Sec->getType() == SHT_NOTE)
       Phdrs[NoteNum].add(Sec);
   }
   return Phdrs;
 }
 
 template <class ELFT>
 ArrayRef<uint8_t> LinkerScript<ELFT>::getFiller(StringRef Name) {
-  auto I = Opt.Filler.find(Name);
-  if (I == Opt.Filler.end())
-    return {};
-  return I->second;
+  for (const std::unique_ptr<BaseCommand> &Base : Opt.Commands)
+    if (auto *Cmd = dyn_cast<OutputSectionCommand>(Base.get()))
+      if (Cmd->Name == Name)
+        return Cmd->Filler;
 }
 
 // Returns the index of the given section name in linker script
 // SECTIONS commands. Sections are laid out as the same order as they
 // were in the script. If a given name did not appear in the script,
 // it returns INT_MAX, so that it will be laid out at end of file.
 template <class ELFT> int LinkerScript<ELFT>::getSectionIndex(StringRef Name) {
   auto Begin = Opt.Commands.begin();
void ScriptParser::readOutputSectionDescription(StringRef OutSec) {
 
   StringRef Tok = peek();
   if (Tok.startswith("=")) {
     if (!Tok.startswith("=0x")) {
       setError("filler should be a hexadecimal value");
       return;
     }
     Tok = Tok.substr(3);
-    Opt.Filler[OutSec] = parseHex(Tok);
+    Cmd->Filler = parseHex(Tok);
     next();
   }
 }
 
 void ScriptParser::readSymbolAssignment(StringRef Name) {
   expect("=");
   std::vector<StringRef> Expr = readSectionsCommandExpr();
   if (Expr.empty())