Strip @VER suffices from the LTO output

[• espindola]

Summary

This fixes pr36623.

The problem is that we have to parse versions out of names before LTO so that LTO can use that information.

When we get the LTO produced .o files, we replace the previous symbols with the LTO produced ones, but they still have @ in them.

We could just trim the name directly, but calling parseSymbolVersion to do it is simpler.

[ruiu]

LGTM

ELF/InputFiles.cpp

269

off-topic, but maybe we should rename this FirstGlobal. NonLocal is probably more technically correct, but colloquially Local <-> Global is much easier to digest.

[• espindola]

328738

ELF/InputFiles.cpp

269

LGTM. We already use global to mean non local in other parts of the linker.

ELF/InputFiles.h

template <class ELFT> class ObjFile : public ELFFileBase<ELFT> {
   StringRef getShtGroupSignature(ArrayRef<Elf_Shdr> Sections,
                                  const Elf_Shdr &Sec);
   ArrayRef<Elf_Word> getShtGroupEntries(const Elf_Shdr &Sec);
 
 public:
   static bool classof(const InputFile *F) { return F->kind() == Base::ObjKind; }
 
   ArrayRef<Symbol *> getLocalSymbols();
+  ArrayRef<Symbol *> getGlobalSymbols();
 
   ObjFile(MemoryBufferRef M, StringRef ArchiveName);
   void parse(llvm::DenseSet<llvm::CachedHashStringRef> &ComdatGroups);
 
   Symbol &getSymbol(uint32_t SymbolIndex) const {
     if (SymbolIndex >= this->Symbols.size())
       fatal(toString(this) + ": invalid symbol index");
     return *this->Symbols[SymbolIndex];

ELF/InputFiles.cpp

 }
 
 template <class ELFT> ArrayRef<Symbol *> ObjFile<ELFT>::getLocalSymbols() {
   if (this->Symbols.empty())
     return {};
   return makeArrayRef(this->Symbols).slice(1, this->FirstNonLocal - 1);
 }
 
+template <class ELFT> ArrayRef<Symbol *> ObjFile<ELFT>::getGlobalSymbols() {
+  return makeArrayRef(this->Symbols).slice(this->FirstNonLocal);
+}
+
 template <class ELFT>
 void ObjFile<ELFT>::parse(DenseSet<CachedHashStringRef> &ComdatGroups) {
   // Read section and symbol tables.
   initializeSections(ComdatGroups);
   initializeSymbols();
 }
 
 // Sections with SHT_GROUP and comdat bits define comdat section groups.

ELF/SymbolTable.cpp

template <class ELFT> void SymbolTable::addCombinedLTOObject() {
 
   // Compile bitcode files and replace bitcode symbols.
   LTO.reset(new BitcodeCompiler);
   for (BitcodeFile *F : BitcodeFiles)
     LTO->add(*F);
 
   for (InputFile *File : LTO->compile()) {
     DenseSet<CachedHashStringRef> DummyGroups;
-    cast<ObjFile<ELFT>>(File)->parse(DummyGroups);
+    auto *Obj = cast<ObjFile<ELFT>>(File);
+    Obj->parse(DummyGroups);
+    for (Symbol *Sym : Obj->getGlobalSymbols())
+      Sym->parseSymbolVersion();
     ObjectFiles.push_back(File);
   }
 }
 
 Defined *SymbolTable::addAbsolute(StringRef Name, uint8_t Visibility,
                                   uint8_t Binding) {
   Symbol *Sym =
       addRegular(Name, Visibility, STT_NOTYPE, 0, 0, Binding, nullptr, nullptr);

test/ELF/lto/version-script2.ll

+; REQUIRES: x86
+; RUN: llvm-as %s -o %t.o
+; RUN: echo "VER1 {};" > %t.script
+; RUN: ld.lld %t.o -o %t.so -shared --version-script %t.script
+; RUN: llvm-readobj -dyn-symbols %t.so | FileCheck %s
+
+; test that we have the correct version.
+; CHECK: Name: foo@@VER1 (
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+module asm ".global foo"
+module asm "foo:"
+module asm ".symver foo,foo@@@VER1"