[ELF] - Linkerscript: remove getSectionMap()

[grimar]

Summary

I think recent patches shows that getSectionMap() is a bit excessive,
since anyways we need to have access to base command somehow in createSections().
At the same time one of pending patches moves "Add" lambda out from this method,
what will make it a bit shorter.
So I suggest to remove getSectionMap() for simplification.

[grimar]

We can live without this for now.

ELF/LinkerScript.h

public:
   ArrayRef<uint8_t> getFiller(StringRef Name);
   bool shouldKeep(InputSectionBase<ELFT> *S);
   void assignAddresses(ArrayRef<OutputSectionBase<ELFT> *> S);
   int compareSections(StringRef A, StringRef B);
   void addScriptedSymbols();
   bool hasPhdrsCommands();
 
 private:
-  std::vector<std::pair<StringRef, const InputSectionDescription *>>
-  getSectionMap();
-
   std::vector<InputSectionBase<ELFT> *>
   getInputSections(const InputSectionDescription *);
 
   // "ScriptConfig" is a bit too long, so define a short name for it.
   ScriptConfiguration &Opt = *ScriptConfig;
 
   std::vector<OutputSectionBase<ELFT> *>
   filter(std::vector<OutputSectionBase<ELFT> *> &Sections);

ELF/LinkerScript.cpp

 
 static bool match(ArrayRef<StringRef> Patterns, StringRef S) {
   for (StringRef Pat : Patterns)
     if (globMatch(Pat, S))
       return true;
   return false;
 }
 
-// Create a vector of (<output section name>, <input section name patterns>).
-// For example, if a returned vector contains (".text" (".foo.*" ".bar.*")),
-// input sections start with ".foo." or ".bar." should be added to
-// ".text" section.
-template <class ELFT>
-std::vector<std::pair<StringRef, const InputSectionDescription *>>
-LinkerScript<ELFT>::getSectionMap() {
-  std::vector<std::pair<StringRef, const InputSectionDescription *>> Ret;
-
-  for (const std::unique_ptr<BaseCommand> &Base1 : Opt.Commands)
-    if (auto *Cmd1 = dyn_cast<OutputSectionCommand>(Base1.get()))
-      for (const std::unique_ptr<BaseCommand> &Base2 : Cmd1->Commands)
-        if (auto *Cmd2 = dyn_cast<InputSectionDescription>(Base2.get()))
-          Ret.emplace_back(Cmd1->Name, Cmd2);
-
-  return Ret;
-}
-
 // Returns input sections filtered by given glob patterns.
 template <class ELFT>
 std::vector<InputSectionBase<ELFT> *>
 LinkerScript<ELFT>::getInputSections(const InputSectionDescription *I) {
   ArrayRef<StringRef> Patterns = I->Patterns;
   ArrayRef<StringRef> ExcludedFiles = I->ExcludedFiles;
   std::vector<InputSectionBase<ELFT> *> Ret;
   for (const std::unique_ptr<ObjectFile<ELFT>> &F :
auto Add = [&](InputSectionBase<ELFT> *C, StringRef Name) {
     OutputSectionBase<ELFT> *Sec;
     bool IsNew;
     std::tie(Sec, IsNew) = Factory.create(C, Name);
     if (IsNew)
       Ret.push_back(Sec);
     Sec->addSection(C);
   };
 
-  for (auto &P : getSectionMap()) {
-    StringRef OutputName = P.first;
-    const InputSectionDescription *I = P.second;
-    for (InputSectionBase<ELFT> *S : getInputSections(I)) {
-      if (OutputName == "/DISCARD/") {
+  for (const std::unique_ptr<BaseCommand> &Base1 : Opt.Commands) {
+    if (auto *OutCmd = dyn_cast<OutputSectionCommand>(Base1.get())) {
+      for (const std::unique_ptr<BaseCommand> &Base2 : OutCmd->Commands) {
+        auto *InCmd = dyn_cast<InputSectionDescription>(Base2.get());
+        if (!InCmd)
+          continue;
+
+        for (InputSectionBase<ELFT> *S : getInputSections(InCmd)) {
+          if (OutCmd->Name == "/DISCARD/") {
             S->Live = false;
             reportDiscarded(S);
             continue;
           }
-      Add(S, OutputName);
+          Add(S, OutCmd->Name);
+        }
+      }
     }
   }
 
   // Add all other input sections, which are not listed in script.
   for (const std::unique_ptr<ObjectFile<ELFT>> &F :
        Symtab<ELFT>::X->getObjectFiles())
     for (InputSectionBase<ELFT> *S : F->getSections())
       if (!isDiscarded(S) && !S->OutSec)