[ELF] - Implemented -z combrelocs/nocombreloc.

This is the option which sorts relocs to optimize dynamic linker performance.
-z combelocs is the default in gold, also it ignores -z nocombreloc,
this patch do the same.

Patch sorts relocations by symbols only and do not create any
DT_REL[A]COUNT entries. That is different with what gold/bfd do.

More information about option is here:
http://www.airs.com/blog/archives/186
http://people.redhat.com/jakub/prelink.pdf, p.2

Differential revision: http://reviews.llvm.org/D19528

llvm-svn: 269066

1 files changed, 2 insertions, 1 deletions

diff --git a/lld/ELF/OutputSections.h b/lld/ELF/OutputSections.h
index d8c0e5b7484..b94f76588e6 100644
--- a/lld/ELF/OutputSections.h
+++ b/lld/ELF/OutputSections.h
@@ -274,7 +274,7 @@ class RelocationSection final : public OutputSectionBase<ELFT> {
   typedef typename ELFT::uint uintX_t;
 
 public:
-  RelocationSection(StringRef Name);
+  RelocationSection(StringRef Name, bool Sort);
   void addReloc(const DynamicReloc<ELFT> &Reloc);
   unsigned getRelocOffset();
   void finalize() override;
@@ -284,6 +284,7 @@ public:
   bool Static = false;
 
 private:
+  bool Sort;
   std::vector<DynamicReloc<ELFT>> Relocs;
 };