[ELF] - Linkerscript cleanup of LinkerScript<ELFT>::createSections()

[grimar]

Summary

Change extracted from D22749.

[• rafael]

LGTM with one change.

ELF/LinkerScript.cpp

139

Please keep the filter in getSectionMap for now.

[grimar]

In D22962#500640, @rafael wrote:

LGTM with one change.

With this change it transforms almost to the same code. Actually comment of LinkerScript<ELFT>::getSectionMap() was depricated and I did not notice it returns InputSectionDescription already.

So my patch can live without that change I think. Do you still think it is useful ?

[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 *>>
+  std::vector<std::pair<StringRef, std::vector<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;
 

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.
+// Create a vector of (<name>, list of <InputSectionDescription *>).
 template <class ELFT>
-std::vector<std::pair<StringRef, const InputSectionDescription *>>
+std::vector<std::pair<StringRef, std::vector<InputSectionDescription *>>>
 LinkerScript<ELFT>::getSectionMap() {
-  std::vector<std::pair<StringRef, const InputSectionDescription *>> Ret;
-
+  std::vector<std::pair<StringRef, std::vector<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);
-
+    if (auto *Cmd1 = dyn_cast<OutputSectionCommand>(Base1.get())) {
+      std::vector<InputSectionDescription *> Commands;
+      for (const std::unique_ptr<BaseCommand> &Cmd : Cmd1->Commands)
+        if (auto *InCmd = dyn_cast<InputSectionDescription>(Cmd.get()))
+          Commands.push_back(InCmd);
+      Ret.emplace_back(Cmd1->Name, std::move(Commands));
+    }
   return Ret;
 }
 
 static bool fileMatches(const InputSectionDescription *Desc,
                         StringRef Filename) {
   if (!globMatch(Desc->FilePattern, Filename))
     return false;
   return Desc->ExcludedFiles.empty() || !match(Desc->ExcludedFiles, Filename);
auto Add = [&](InputSectionBase<ELFT> *C, StringRef Name) {
     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)) {
+    for (InputSectionDescription *InCmd : P.second) {
+      for (InputSectionBase<ELFT> *S : getInputSections(InCmd)) {
         if (OutputName == "/DISCARD/") {
           S->Live = false;
           reportDiscarded(S);
           continue;
         }
         Add(S, OutputName);
       }
     }
+  }
 
   // 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)
         Add(S, getOutputSectionName(S));