[ELF] - Basic versioned symbols support implemented.

Patch implements basic support of versioned symbols.
There is no wildcards patterns matching except local: *;
There is no support for hierarchies.
There is no support for symbols overrides (@ vs @@ not handled).

This patch allows programs that using simple scripts to link and run.

Differential revision: http://reviews.llvm.org/D21018

llvm-svn: 273143

1 files changed, 11 insertions, 2 deletions

diff --git a/lld/ELF/Writer.cpp b/lld/ELF/Writer.cpp
index 65ddb2010db..d5761e79292 100644
--- a/lld/ELF/Writer.cpp
+++ b/lld/ELF/Writer.cpp
@@ -136,6 +136,7 @@ template <class ELFT> void elf::writeResult(SymbolTable<ELFT> *Symtab) {
   std::unique_ptr<StringTableSection<ELFT>> StrTab;
   std::unique_ptr<SymbolTableSection<ELFT>> SymTabSec;
   std::unique_ptr<OutputSection<ELFT>> MipsRldMap;
+  std::unique_ptr<VersionDefinitionSection<ELFT>> VerDef;
 
   if (Config->BuildId == BuildIdKind::Fnv1)
     BuildId.reset(new BuildIdFnv1<ELFT>);
@@ -170,6 +171,8 @@ template <class ELFT> void elf::writeResult(SymbolTable<ELFT> *Symtab) {
     MipsRldMap->setSize(sizeof(uintX_t));
     MipsRldMap->updateAlignment(sizeof(uintX_t));
   }
+  if (!Config->SymbolVersions.empty())
+    VerDef.reset(new VersionDefinitionSection<ELFT>());
 
   Out<ELFT>::Bss = &Bss;
   Out<ELFT>::BuildId = BuildId.get();
@@ -189,6 +192,7 @@ template <class ELFT> void elf::writeResult(SymbolTable<ELFT> *Symtab) {
   Out<ELFT>::ShStrTab = &ShStrTab;
   Out<ELFT>::StrTab = StrTab.get();
   Out<ELFT>::SymTab = SymTabSec.get();
+  Out<ELFT>::VerDef = VerDef.get();
   Out<ELFT>::VerSym = &VerSym;
   Out<ELFT>::VerNeed = &VerNeed;
   Out<ELFT>::MipsRldMap = MipsRldMap.get();
@@ -904,10 +908,15 @@ template <class ELFT> void Writer<ELFT>::addPredefinedSections() {
   Add(Out<ELFT>::StrTab);
   if (isOutputDynamic()) {
     Add(Out<ELFT>::DynSymTab);
-    if (Out<ELFT>::VerNeed->getNeedNum() != 0) {
+
+    bool HasVerNeed = Out<ELFT>::VerNeed->getNeedNum() != 0;
+    if (Out<ELFT>::VerDef || HasVerNeed)
       Add(Out<ELFT>::VerSym);
+    if (Out<ELFT>::VerDef)
+      Add(Out<ELFT>::VerDef);
+    if (HasVerNeed)
       Add(Out<ELFT>::VerNeed);
-    }
+
     Add(Out<ELFT>::GnuHashTab);
     Add(Out<ELFT>::HashTab);
     Add(Out<ELFT>::Dynamic);