Split addSection into two small functions. NFCI.

addSection function was hard to read because it behaves differently
depending on its arguments but what exactly it does is not clear.
Now it should be better. Still, it is not clear (not what but) why
it does what it does, but I'll take a look at it later.

llvm-svn: 315124

lld/ELF/LinkerScript.cpp

@@ -458,7 +458,7 @@ void LinkerScript::addOrphanSections(OutputSectionFactory &Factory) {
     });
     log(toString(S) + " is being placed in '" + Name + "'");
     if (I == End) {
-      Factory.addInputSec(S, Name);
+      Factory.addInputSec(S, Name, nullptr);
       assert(S->getOutputSection()->SectionIndex == INT_MAX);
     } else {
       OutputSection *Sec = cast<OutputSection>(*I);

lld/ELF/OutputSections.cpp

@@ -200,14 +200,25 @@ void elf::reportDiscarded(InputSectionBase *IS) {
           IS->File->getName() + "'");
 }
 
-static OutputSection *addSection(InputSectionBase *IS, StringRef OutsecName,
-                                 OutputSection *Sec) {
-  if (Sec && Sec->Live) {
+static OutputSection *createSection(InputSectionBase *IS, StringRef OutsecName) {
+  OutputSection *Sec = Script->createOutputSection(OutsecName, "<internal>");
+  Sec->Type = IS->Type;
+  Sec->Flags = IS->Flags;
+  Sec->addSection(cast<InputSection>(IS));
+
+  Script->Opt.Commands.push_back(Sec);
+
+  return Sec;
+}
+
+static void addSection(OutputSection *Sec, InputSectionBase *IS, StringRef OutsecName) {
+  if (Sec->Live) {
     if (getIncompatibleFlags(Sec->Flags) != getIncompatibleFlags(IS->Flags))
       error("incompatible section flags for " + Sec->Name + "\n>>> " +
             toString(IS) + ": 0x" + utohexstr(IS->Flags) +
             "\n>>> output section " + Sec->Name + ": 0x" +
             utohexstr(Sec->Flags));
+
     if (Sec->Type != IS->Type) {
       if (canMergeToProgbits(Sec->Type) && canMergeToProgbits(IS->Type))
         Sec->Type = SHT_PROGBITS;
@@ -218,18 +229,12 @@ static OutputSection *addSection(InputSectionBase *IS, StringRef OutsecName,
               "\n>>> output section " + Sec->Name + ": " +
               getELFSectionTypeName(Config->EMachine, Sec->Type));
     }
-    Sec->Flags |= IS->Flags;
   } else {
-    if (!Sec) {
-      Sec = Script->createOutputSection(OutsecName, "<internal>");
-      Script->Opt.Commands.push_back(Sec);
-    }
     Sec->Type = IS->Type;
-    Sec->Flags = IS->Flags;
   }
 
+  Sec->Flags |= IS->Flags;
   Sec->addSection(cast<InputSection>(IS));
-  return Sec;
 }
 
 void OutputSectionFactory::addInputSec(InputSectionBase *IS,
@@ -242,7 +247,7 @@ void OutputSectionFactory::addInputSec(InputSectionBase *IS,
 
   // If we have destination output section - use it directly.
   if (OS) {
-    addSection(IS, OutsecName, OS);
+    addSection(OS, IS, OutsecName);
     return;
   }
 
@@ -254,7 +259,7 @@ void OutputSectionFactory::addInputSec(InputSectionBase *IS,
   // as-is because adding/removing members or merging them with other groups
   // change their semantics.
   if (IS->Type == SHT_GROUP || (IS->Flags & SHF_GROUP)) {
-    addSection(IS, OutsecName, nullptr);
+    createSection(IS, OutsecName);
     return;
   }
 
@@ -268,13 +273,20 @@ void OutputSectionFactory::addInputSec(InputSectionBase *IS,
       (IS->Type == SHT_REL || IS->Type == SHT_RELA)) {
     auto *Sec = cast<InputSection>(IS);
     OutputSection *Out = Sec->getRelocatedSection()->getOutputSection();
-    Out->RelocationSection = addSection(IS, OutsecName, Out->RelocationSection);
+
+    if (Out->RelocationSection)
+      addSection(Out->RelocationSection, IS, OutsecName);
+    else
+      Out->RelocationSection = createSection(IS, OutsecName);
     return;
   }
 
   SectionKey Key = createKey(IS, OutsecName);
   OutputSection *&Sec = Map[Key];
-  Sec = addSection(IS, OutsecName, Sec);
+  if (Sec)
+    addSection(Sec, IS, OutsecName);
+  else
+    Sec = createSection(IS, OutsecName);
 }
 
 OutputSectionFactory::~OutputSectionFactory() {}

lld/ELF/OutputSections.h

@@ -165,7 +165,7 @@ public:
   ~OutputSectionFactory();
 
   void addInputSec(InputSectionBase *IS, StringRef OutsecName,
-                   OutputSection *OS = nullptr);
+                   OutputSection *OS);
 
 private:
   llvm::SmallDenseMap<SectionKey, OutputSection *> Map;

lld/ELF/Writer.cpp

@@ -880,7 +880,7 @@ template <class ELFT> void Writer<ELFT>::createSections() {
   Script->Opt.Commands.clear();
   for (InputSectionBase *IS : InputSections)
     if (IS)
-      Factory.addInputSec(IS, getOutputSectionName(IS->Name));
+      Factory.addInputSec(IS, getOutputSectionName(IS->Name), nullptr);
   Script->Opt.Commands.insert(Script->Opt.Commands.end(), Old.begin(),
                               Old.end());