[ORC][JITLink][ELF] Treat STB_GNU_UNIQUE as Weak in the JIT.

This should fix the bot error in
https://lab.llvm.org/buildbot/#/builders/112/builds/8599
which forced reversion of the ELFNixPlatform in 45ac5f5.

This should allow us to re-enable the ELFNixPlatform in a follow-up patch.

Author: lhames

llvm/lib/ExecutionEngine/JITLink/ELFLinkGraphBuilder.h

@@ -170,6 +170,7 @@ ELFLinkGraphBuilder<ELFT>::getSymbolLinkageAndScope(
     // Nothing to do here.
     break;
   case ELF::STB_WEAK:
+  case ELF::STB_GNU_UNIQUE:
     L = Linkage::Weak;
     break;
   default:

llvm/lib/ExecutionEngine/Orc/Mangling.cpp

@@ -10,6 +10,7 @@
 #include "llvm/ExecutionEngine/Orc/MachOPlatform.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/Mangler.h"
+#include "llvm/Object/ELFObjectFile.h"
 #include "llvm/Object/MachO.h"
 #include "llvm/Object/ObjectFile.h"
 #include "llvm/Support/Debug.h"
@@ -83,17 +84,12 @@ void IRSymbolMapper::add(ExecutionSession &ES, const ManglingOptions &MO,
   }
 }
 
-Expected<std::pair<SymbolFlagsMap, SymbolStringPtr>>
-getObjectSymbolInfo(ExecutionSession &ES, MemoryBufferRef ObjBuffer) {
-  auto Obj = object::ObjectFile::createObjectFile(ObjBuffer);
-
-  if (!Obj)
-    return Obj.takeError();
-
-  bool IsMachO = isa<object::MachOObjectFile>(Obj->get());
-
+static Expected<std::pair<SymbolFlagsMap, SymbolStringPtr>>
+getMachOObjectFileSymbolInfo(ExecutionSession &ES,
+                             const object::MachOObjectFile &Obj) {
   SymbolFlagsMap SymbolFlags;
-  for (auto &Sym : (*Obj)->symbols()) {
+
+  for (auto &Sym : Obj.symbols()) {
     Expected<uint32_t> SymFlagsOrErr = Sym.getFlags();
     if (!SymFlagsOrErr)
       // TODO: Test this error.
@@ -123,21 +119,19 @@ getObjectSymbolInfo(ExecutionSession &ES, MemoryBufferRef ObjBuffer) {
       return SymFlags.takeError();
 
     // Strip the 'exported' flag from MachO linker-private symbols.
-    if (IsMachO && Name->startswith("l"))
+    if (Name->startswith("l"))
       *SymFlags &= ~JITSymbolFlags::Exported;
 
     SymbolFlags[InternedName] = std::move(*SymFlags);
   }
 
   SymbolStringPtr InitSymbol;
-
   size_t Counter = 0;
   auto AddInitSymbol = [&]() {
     while (true) {
       std::string InitSymString;
       raw_string_ostream(InitSymString)
-          << "$." << ObjBuffer.getBufferIdentifier() << ".__inits."
-          << Counter++;
+          << "$." << Obj.getFileName() << ".__inits." << Counter++;
       InitSymbol = ES.intern(InitSymString);
       if (SymbolFlags.count(InitSymbol))
         continue;
@@ -146,26 +140,119 @@ getObjectSymbolInfo(ExecutionSession &ES, MemoryBufferRef ObjBuffer) {
     }
   };
 
-  if (IsMachO) {
-    auto &MachOObj = cast<object::MachOObjectFile>(*Obj->get());
-    for (auto &Sec : MachOObj.sections()) {
-      auto SecType = MachOObj.getSectionType(Sec);
-      if ((SecType & MachO::SECTION_TYPE) == MachO::S_MOD_INIT_FUNC_POINTERS) {
-        AddInitSymbol();
-        break;
-      }
-      auto SegName =
-          MachOObj.getSectionFinalSegmentName(Sec.getRawDataRefImpl());
-      auto SecName = cantFail(MachOObj.getSectionName(Sec.getRawDataRefImpl()));
-      if (MachOPlatform::isInitializerSection(SegName, SecName)) {
-        AddInitSymbol();
-        break;
-      }
+  for (auto &Sec : Obj.sections()) {
+    auto SecType = Obj.getSectionType(Sec);
+    if ((SecType & MachO::SECTION_TYPE) == MachO::S_MOD_INIT_FUNC_POINTERS) {
+      AddInitSymbol();
+      break;
+    }
+    auto SegName = Obj.getSectionFinalSegmentName(Sec.getRawDataRefImpl());
+    auto SecName = cantFail(Obj.getSectionName(Sec.getRawDataRefImpl()));
+    if (MachOPlatform::isInitializerSection(SegName, SecName)) {
+      AddInitSymbol();
+      break;
     }
   }
 
   return std::make_pair(std::move(SymbolFlags), std::move(InitSymbol));
 }
 
+static Expected<std::pair<SymbolFlagsMap, SymbolStringPtr>>
+getELFObjectFileSymbolInfo(ExecutionSession &ES,
+                           const object::ELFObjectFileBase &Obj) {
+  SymbolFlagsMap SymbolFlags;
+  for (auto &Sym : Obj.symbols()) {
+    Expected<uint32_t> SymFlagsOrErr = Sym.getFlags();
+    if (!SymFlagsOrErr)
+      // TODO: Test this error.
+      return SymFlagsOrErr.takeError();
+
+    // Skip symbols not defined in this object file.
+    if (*SymFlagsOrErr & object::BasicSymbolRef::SF_Undefined)
+      continue;
+
+    // Skip symbols that are not global.
+    if (!(*SymFlagsOrErr & object::BasicSymbolRef::SF_Global))
+      continue;
+
+    // Skip symbols that have type SF_File.
+    if (auto SymType = Sym.getType()) {
+      if (*SymType == object::SymbolRef::ST_File)
+        continue;
+    } else
+      return SymType.takeError();
+
+    auto Name = Sym.getName();
+    if (!Name)
+      return Name.takeError();
+    auto InternedName = ES.intern(*Name);
+    auto SymFlags = JITSymbolFlags::fromObjectSymbol(Sym);
+    if (!SymFlags)
+      return SymFlags.takeError();
+
+    // ELF STB_GNU_UNIQUE should map to Weak for ORC.
+    if (Sym.getBinding() == ELF::STB_GNU_UNIQUE)
+      *SymFlags |= JITSymbolFlags::Weak;
+
+    SymbolFlags[InternedName] = std::move(*SymFlags);
+  }
+
+  return std::make_pair(std::move(SymbolFlags), nullptr);
+}
+
+Expected<std::pair<SymbolFlagsMap, SymbolStringPtr>>
+getGenericObjectFileSymbolInfo(ExecutionSession &ES,
+                               const object::ObjectFile &Obj) {
+  SymbolFlagsMap SymbolFlags;
+  for (auto &Sym : Obj.symbols()) {
+    Expected<uint32_t> SymFlagsOrErr = Sym.getFlags();
+    if (!SymFlagsOrErr)
+      // TODO: Test this error.
+      return SymFlagsOrErr.takeError();
+
+    // Skip symbols not defined in this object file.
+    if (*SymFlagsOrErr & object::BasicSymbolRef::SF_Undefined)
+      continue;
+
+    // Skip symbols that are not global.
+    if (!(*SymFlagsOrErr & object::BasicSymbolRef::SF_Global))
+      continue;
+
+    // Skip symbols that have type SF_File.
+    if (auto SymType = Sym.getType()) {
+      if (*SymType == object::SymbolRef::ST_File)
+        continue;
+    } else
+      return SymType.takeError();
+
+    auto Name = Sym.getName();
+    if (!Name)
+      return Name.takeError();
+    auto InternedName = ES.intern(*Name);
+    auto SymFlags = JITSymbolFlags::fromObjectSymbol(Sym);
+    if (!SymFlags)
+      return SymFlags.takeError();
+
+    SymbolFlags[InternedName] = std::move(*SymFlags);
+  }
+
+  return std::make_pair(std::move(SymbolFlags), nullptr);
+}
+
+Expected<std::pair<SymbolFlagsMap, SymbolStringPtr>>
+getObjectSymbolInfo(ExecutionSession &ES, MemoryBufferRef ObjBuffer) {
+  auto Obj = object::ObjectFile::createObjectFile(ObjBuffer);
+
+  if (!Obj)
+    return Obj.takeError();
+
+  if (auto *MachOObj = dyn_cast<object::MachOObjectFile>(Obj->get()))
+    return getMachOObjectFileSymbolInfo(ES, *MachOObj);
+  else if (auto *ELFObj = dyn_cast<object::ELFObjectFileBase>(Obj->get()))
+    return getELFObjectFileSymbolInfo(ES, *ELFObj);
+
+  return getGenericObjectFileSymbolInfo(ES, **Obj);
+}
+
 } // End namespace orc.
 } // End namespace llvm.