[ELF] - Add predefined sections to output sections list in one place.

Minor cleanup.
Currently it looks wierd that having method addPredefinedSections()
we still add 2 sections outside it without real reasons.
Patch fixes that.

Differential revision: http://reviews.llvm.org/D19981

llvm-svn: 275269

lld/ELF/Writer.cpp

@@ -604,17 +604,6 @@ template <class ELFT> static void sortCtorsDtors(OutputSectionBase<ELFT> *S) {
 
 // Create output section objects and add them to OutputSections.
 template <class ELFT> void Writer<ELFT>::createSections() {
-  // Add .interp first because some loaders want to see that section
-  // on the first page of the executable file when loaded into memory.
-  if (needsInterpSection())
-    OutputSections.push_back(Out<ELFT>::Interp);
-
-  // A core file does not usually contain unmodified segments except
-  // the first page of the executable. Add the build ID section now
-  // so that the section is included in the first page.
-  if (Out<ELFT>::BuildId)
-    OutputSections.push_back(Out<ELFT>::BuildId);
-
   // Create output sections for input object file sections.
   std::vector<OutputSectionBase<ELFT> *> RegularSections;
   OutputSectionFactory<ELFT> Factory;
@@ -793,6 +782,17 @@ template <class ELFT> void Writer<ELFT>::addPredefinedSections() {
       OutputSections.push_back(C);
   };
 
+  // A core file does not usually contain unmodified segments except
+  // the first page of the executable. Add the build ID section to beginning of
+  // the file so that the section is included in the first page.
+  if (Out<ELFT>::BuildId)
+    OutputSections.insert(OutputSections.begin(), Out<ELFT>::BuildId);
+
+  // Add .interp at first because some loaders want to see that section
+  // on the first page of the executable file when loaded into memory.
+  if (needsInterpSection())
+    OutputSections.insert(OutputSections.begin(), Out<ELFT>::Interp);
+
   // This order is not the same as the final output order
   // because we sort the sections using their attributes below.
   Add(Out<ELFT>::SymTab);