Simplify output section ownership.

[ruiu]

Summary

This patch simplifies output section management by making
Factory class have ownership of sections that creates.

[evgeny777]

LGTM

lld/trunk/ELF/LinkerScript.h

 
 // This is a runner of the linker script.
 template <class ELFT> class LinkerScript {
   typedef typename ELFT::uint uintX_t;
 
 public:
   typedef PhdrEntry<ELFT> Phdr;
 
+  std::vector<OutputSectionBase<ELFT> *>
+  createSections(OutputSectionFactory<ELFT> &Factory);
+
   StringRef getOutputSection(InputSectionBase<ELFT> *S);
   ArrayRef<uint8_t> getFiller(StringRef Name);
   bool isDiscarded(InputSectionBase<ELFT> *S);
   bool shouldKeep(InputSectionBase<ELFT> *S);
-  std::vector<std::unique_ptr<OutputSectionBase<ELFT>>>
-  createSections(OutputSectionFactory<ELFT> &Factory);
   void assignAddresses(ArrayRef<OutputSectionBase<ELFT> *> S);
   int compareSections(StringRef A, StringRef B);
   void addScriptedSymbols();
   std::vector<Phdr> createPhdrs(ArrayRef<OutputSectionBase<ELFT> *> S);
   bool hasPhdrsCommands();
 
 private:
   // "ScriptConfig" is a bit too long, so define a short name for it.

lld/trunk/ELF/LinkerScript.cpp

 bool LinkerScript<ELFT>::shouldKeep(InputSectionBase<ELFT> *S) {
   for (StringRef Pat : Opt.KeptSections)
     if (globMatch(Pat, S->getSectionName()))
       return true;
   return false;
 }
 
 template <class ELFT>
-std::vector<std::unique_ptr<OutputSectionBase<ELFT>>>
+std::vector<OutputSectionBase<ELFT> *>
 LinkerScript<ELFT>::createSections(OutputSectionFactory<ELFT> &Factory) {
-  std::vector<std::unique_ptr<OutputSectionBase<ELFT>>> Result;
+  std::vector<OutputSectionBase<ELFT> *> Result;
+
   // Add input section to output section. If there is no output section yet,
   // then create it and add to output section list.
   auto AddInputSec = [&](InputSectionBase<ELFT> *C, StringRef Name) {
     OutputSectionBase<ELFT> *Sec;
     bool IsNew;
     std::tie(Sec, IsNew) = Factory.create(C, Name);
     if (IsNew)
-      Result.emplace_back(Sec);
+      Result.push_back(Sec);
     Sec->addSection(C);
   };
 
   // Select input sections matching rule and add them to corresponding
   // output section. Section rules are processed in order they're listed
   // in script, so correct input section order is maintained by design.
   for (SectionRule &R : Opt.Sections)
     for (const std::unique_ptr<ObjectFile<ELFT>> &F :

lld/trunk/ELF/OutputSections.h

std::pair<OutputSectionBase<ELFT> *, bool> create(InputSectionBase<ELFT> *C,
                                                     StringRef OutsecName);
 
   OutputSectionBase<ELFT> *lookup(StringRef Name, uint32_t Type, uintX_t Flags);
 
 private:
   Key createKey(InputSectionBase<ELFT> *C, StringRef OutsecName);
 
   llvm::SmallDenseMap<Key, OutputSectionBase<ELFT> *> Map;
+  std::vector<std::unique_ptr<OutputSectionBase<ELFT>>> OwningSections;
 };
 
 template <class ELFT> BuildIdSection<ELFT> *Out<ELFT>::BuildId;
 template <class ELFT> DynamicSection<ELFT> *Out<ELFT>::Dynamic;
 template <class ELFT> EhFrameHeader<ELFT> *Out<ELFT>::EhFrameHdr;
 template <class ELFT> EhOutputSection<ELFT> *Out<ELFT>::EhFrame;
 template <class ELFT> GnuHashTableSection<ELFT> *Out<ELFT>::GnuHashTab;
 template <class ELFT> GotPltSection<ELFT> *Out<ELFT>::GotPlt;

lld/trunk/ELF/OutputSections.cpp

case InputSectionBase<ELFT>::Merge:
     break;
   case InputSectionBase<ELFT>::MipsReginfo:
     Sec = new MipsReginfoOutputSection<ELFT>();
     break;
   case InputSectionBase<ELFT>::MipsOptions:
     Sec = new MipsOptionsOutputSection<ELFT>();
     break;
   }
+  OwningSections.emplace_back(Sec);
   return {Sec, true};
 }
 
 template <class ELFT>
 OutputSectionBase<ELFT> *OutputSectionFactory<ELFT>::lookup(StringRef Name,
                                                             uint32_t Type,
                                                             uintX_t Flags) {
   return Map.lookup({Name, Type, Flags, 0});

lld/trunk/ELF/Writer.cpp

public:
   Writer(SymbolTable<ELFT> &S) : Symtab(S) {}
   void run();
 
 private:
   typedef PhdrEntry<ELFT> Phdr;
 
   void copyLocalSymbols();
   void addReservedSymbols();
-  std::vector<std::unique_ptr<OutputSectionBase<ELFT>>> createSections();
+  std::vector<OutputSectionBase<ELFT> *> createSections();
   void finalizeSections();
   void addPredefinedSections();
   bool needsGot();
 
   void createPhdrs();
   void assignAddresses();
   void assignFileOffsets();
   void setPhdrs();

 }
 
 // The main function of the writer.
 template <class ELFT> void Writer<ELFT>::run() {
   if (!Config->DiscardAll)
     copyLocalSymbols();
   addReservedSymbols();
 
-  std::vector<std::unique_ptr<OutputSectionBase<ELFT>>> Sections =
-      ScriptConfig->DoLayout ? Script<ELFT>::X->createSections(Factory)
-                             : createSections();
-
-  for (std::unique_ptr<OutputSectionBase<ELFT>> &S : Sections)
-    OutputSections.push_back(S.get());
-
+  OutputSections = ScriptConfig->DoLayout
+                       ? Script<ELFT>::X->createSections(Factory)
   finalizeSections();
   if (HasError)
     return;
 
   if (Config->Relocatable) {
     assignFileOffsets();
   } else {
     if (Script<ELFT>::X->hasPhdrsCommands())

 
 // Sort input sections by the special rule for .ctors and .dtors.
 template <class ELFT> static void sortCtorsDtors(OutputSectionBase<ELFT> *S) {
   if (S)
     reinterpret_cast<OutputSection<ELFT> *>(S)->sortCtorsDtors();
 }
 
 template <class ELFT>
-std::vector<std::unique_ptr<OutputSectionBase<ELFT>>>
-Writer<ELFT>::createSections() {
-  std::vector<std::unique_ptr<OutputSectionBase<ELFT>>> Result;
+std::vector<OutputSectionBase<ELFT> *> Writer<ELFT>::createSections() {
+  std::vector<OutputSectionBase<ELFT> *> Result;
 
   for (const std::unique_ptr<elf::ObjectFile<ELFT>> &F :
        Symtab.getObjectFiles()) {
     for (InputSectionBase<ELFT> *C : F->getSections()) {
       if (isDiscarded(C)) {
         reportDiscarded(C, F);
         continue;
       }
       OutputSectionBase<ELFT> *Sec;
       bool IsNew;
       std::tie(Sec, IsNew) = Factory.create(C, getOutputSectionName(C));
       if (IsNew)
-        Result.emplace_back(Sec);
-
+        Result.push_back(Sec);
       Sec->addSection(C);
     }
   }
   return Result;
 }
 
 // Create output section objects and add them to OutputSections.
 template <class ELFT> void Writer<ELFT>::finalizeSections() {