Create the new linker type "linker_private_weak_def_auto".

It's similar to "linker_private_weak", but it's known that the address of the
object is not taken. For instance, functions that had an inline definition, but
the compiler decided not to inline it. Note, unlike linker_private and
linker_private_weak, linker_private_weak_def_auto may have only default
visibility.  The symbols are removed by the linker from the final linked image
(executable or dynamic library).

llvm-svn: 111684

11 files changed, 52 insertions, 20 deletions

diff --git a/llvm/lib/AsmParser/LLLexer.cpp b/llvm/lib/AsmParser/LLLexer.cpp
index f4c0e50fd94..90696b950fe 100644
--- a/llvm/lib/AsmParser/LLLexer.cpp
+++ b/llvm/lib/AsmParser/LLLexer.cpp
@@ -493,6 +493,7 @@ lltok::Kind LLLexer::LexIdentifier() {
   KEYWORD(private);
   KEYWORD(linker_private);
   KEYWORD(linker_private_weak);
+  KEYWORD(linker_private_weak_def_auto);
   KEYWORD(internal);
   KEYWORD(available_externally);
   KEYWORD(linkonce);
diff --git a/llvm/lib/AsmParser/LLParser.cpp b/llvm/lib/AsmParser/LLParser.cpp
index dc545fff2da..0c5e04992f0 100644
--- a/llvm/lib/AsmParser/LLParser.cpp
+++ b/llvm/lib/AsmParser/LLParser.cpp
@@ -199,6 +199,7 @@ bool LLParser::ParseTopLevelEntities() {
     case lltok::kw_private:             // OptionalLinkage
     case lltok::kw_linker_private:      // OptionalLinkage
     case lltok::kw_linker_private_weak: // OptionalLinkage
+    case lltok::kw_linker_private_weak_def_auto: // OptionalLinkage
     case lltok::kw_internal:            // OptionalLinkage
     case lltok::kw_weak:                // OptionalLinkage
     case lltok::kw_weak_odr:            // OptionalLinkage
@@ -623,7 +624,8 @@ bool LLParser::ParseAlias(const std::string &Name, LocTy NameLoc,
       Linkage != GlobalValue::InternalLinkage &&
       Linkage != GlobalValue::PrivateLinkage &&
       Linkage != GlobalValue::LinkerPrivateLinkage &&
-      Linkage != GlobalValue::LinkerPrivateWeakLinkage)
+      Linkage != GlobalValue::LinkerPrivateWeakLinkage &&
+      Linkage != GlobalValue::LinkerPrivateWeakDefAutoLinkage)
     return Error(LinkageLoc, "invalid linkage type for alias");
 
   Constant *Aliasee;
@@ -1008,6 +1010,7 @@ bool LLParser::ParseOptionalAttrs(unsigned &Attrs, unsigned AttrKind) {
 ///   ::= 'private'
 ///   ::= 'linker_private'
 ///   ::= 'linker_private_weak'
+///   ::= 'linker_private_weak_def_auto'
 ///   ::= 'internal'
 ///   ::= 'weak'
 ///   ::= 'weak_odr'
@@ -1029,6 +1032,9 @@ bool LLParser::ParseOptionalLinkage(unsigned &Res, bool &HasLinkage) {
   case lltok::kw_linker_private_weak:
     Res = GlobalValue::LinkerPrivateWeakLinkage;
     break;
+  case lltok::kw_linker_private_weak_def_auto:
+    Res = GlobalValue::LinkerPrivateWeakDefAutoLinkage;
+    break;
   case lltok::kw_internal:       Res = GlobalValue::InternalLinkage;      break;
   case lltok::kw_weak:           Res = GlobalValue::WeakAnyLinkage;       break;
   case lltok::kw_weak_odr:       Res = GlobalValue::WeakODRLinkage;       break;
@@ -2718,6 +2724,7 @@ bool LLParser::ParseFunctionHeader(Function *&Fn, bool isDefine) {
   case GlobalValue::PrivateLinkage:
   case GlobalValue::LinkerPrivateLinkage:
   case GlobalValue::LinkerPrivateWeakLinkage:
+  case GlobalValue::LinkerPrivateWeakDefAutoLinkage:
   case GlobalValue::InternalLinkage:
   case GlobalValue::AvailableExternallyLinkage:
   case GlobalValue::LinkOnceAnyLinkage:
diff --git a/llvm/lib/AsmParser/LLToken.h b/llvm/lib/AsmParser/LLToken.h
index 2703134ec1a..e266db994e9 100644
--- a/llvm/lib/AsmParser/LLToken.h
+++ b/llvm/lib/AsmParser/LLToken.h
@@ -37,7 +37,8 @@ namespace lltok {
     kw_declare, kw_define,
     kw_global,  kw_constant,
 
-    kw_private, kw_linker_private, kw_linker_private_weak, kw_internal,
+    kw_private, kw_linker_private, kw_linker_private_weak,
+    kw_linker_private_weak_def_auto, kw_internal,
     kw_linkonce, kw_linkonce_odr, kw_weak, kw_weak_odr, kw_appending,
     kw_dllimport, kw_dllexport, kw_common, kw_available_externally,
     kw_default, kw_hidden, kw_protected,
diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index 2010468824c..2e86abfbc07 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -77,6 +77,7 @@ static GlobalValue::LinkageTypes GetDecodedLinkage(unsigned Val) {
   case 12: return GlobalValue::AvailableExternallyLinkage;
   case 13: return GlobalValue::LinkerPrivateLinkage;
   case 14: return GlobalValue::LinkerPrivateWeakLinkage;
+  case 15: return GlobalValue::LinkerPrivateWeakDefAutoLinkage;
   }
 }
 
diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
index 776c2d4495c..390e4827feb 100644
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -299,21 +299,22 @@ static void WriteTypeTable(const ValueEnumerator &VE, BitstreamWriter &Stream) {
 static unsigned getEncodedLinkage(const GlobalValue *GV) {
   switch (GV->getLinkage()) {
   default: llvm_unreachable("Invalid linkage!");
-  case GlobalValue::ExternalLinkage:            return 0;
-  case GlobalValue::WeakAnyLinkage:             return 1;
-  case GlobalValue::AppendingLinkage:           return 2;
-  case GlobalValue::InternalLinkage:            return 3;
-  case GlobalValue::LinkOnceAnyLinkage:         return 4;
-  case GlobalValue::DLLImportLinkage:           return 5;
-  case GlobalValue::DLLExportLinkage:           return 6;
-  case GlobalValue::ExternalWeakLinkage:        return 7;
-  case GlobalValue::CommonLinkage:              return 8;
-  case GlobalValue::PrivateLinkage:             return 9;
-  case GlobalValue::WeakODRLinkage:             return 10;
-  case GlobalValue::LinkOnceODRLinkage:         return 11;
-  case GlobalValue::AvailableExternallyLinkage: return 12;
-  case GlobalValue::LinkerPrivateLinkage:       return 13;
-  case GlobalValue::LinkerPrivateWeakLinkage:   return 14;
+  case GlobalValue::ExternalLinkage:                 return 0;
+  case GlobalValue::WeakAnyLinkage:                  return 1;
+  case GlobalValue::AppendingLinkage:                return 2;
+  case GlobalValue::InternalLinkage:                 return 3;
+  case GlobalValue::LinkOnceAnyLinkage:              return 4;
+  case GlobalValue::DLLImportLinkage:                return 5;
+  case GlobalValue::DLLExportLinkage:                return 6;
+  case GlobalValue::ExternalWeakLinkage:             return 7;
+  case GlobalValue::CommonLinkage:                   return 8;
+  case GlobalValue::PrivateLinkage:                  return 9;
+  case GlobalValue::WeakODRLinkage:                  return 10;
+  case GlobalValue::LinkOnceODRLinkage:              return 11;
+  case GlobalValue::AvailableExternallyLinkage:      return 12;
+  case GlobalValue::LinkerPrivateLinkage:            return 13;
+  case GlobalValue::LinkerPrivateWeakLinkage:        return 14;
+  case GlobalValue::LinkerPrivateWeakDefAutoLinkage: return 15;
   }
 }
 
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 25b8d990618..fa0b97fab63 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -200,11 +200,17 @@ void AsmPrinter::EmitLinkage(unsigned Linkage, MCSymbol *GVSym) const {
   case GlobalValue::WeakAnyLinkage:
   case GlobalValue::WeakODRLinkage:
   case GlobalValue::LinkerPrivateWeakLinkage:
+  case GlobalValue::LinkerPrivateWeakDefAutoLinkage:
     if (MAI->getWeakDefDirective() != 0) {
       // .globl _foo
       OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
-      // .weak_definition _foo
-      OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefinition);
+
+      if ((GlobalValue::LinkageTypes)Linkage !=
+          GlobalValue::LinkerPrivateWeakDefAutoLinkage)
+        // .weak_definition _foo
+        OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefinition);
+      else
+        OutStreamer.EmitSymbolAttribute(GVSym, MCSA_WeakDefAutoPrivate);
     } else if (MAI->getLinkOnceDirective() != 0) {
       // .globl _foo
       OutStreamer.EmitSymbolAttribute(GVSym, MCSA_Global);
diff --git a/llvm/lib/Target/CppBackend/CPPBackend.cpp b/llvm/lib/Target/CppBackend/CPPBackend.cpp
index 3e21cd1de44..f08559f6e9f 100644
--- a/llvm/lib/Target/CppBackend/CPPBackend.cpp
+++ b/llvm/lib/Target/CppBackend/CPPBackend.cpp
@@ -288,6 +288,8 @@ void CppWriter::printLinkageType(GlobalValue::LinkageTypes LT) {
     Out << "GlobalValue::LinkerPrivateLinkage"; break;
   case GlobalValue::LinkerPrivateWeakLinkage:
     Out << "GlobalValue::LinkerPrivateWeakLinkage"; break;
+  case GlobalValue::LinkerPrivateWeakDefAutoLinkage:
+    Out << "GlobalValue::LinkerPrivateWeakDefAutoLinkage"; break;
   case GlobalValue::AvailableExternallyLinkage:
     Out << "GlobalValue::AvailableExternallyLinkage "; break;
   case GlobalValue::LinkOnceAnyLinkage:
diff --git a/llvm/lib/Target/Mangler.cpp b/llvm/lib/Target/Mangler.cpp
index 2037a911455..49efe75d79d 100644
--- a/llvm/lib/Target/Mangler.cpp
+++ b/llvm/lib/Target/Mangler.cpp
@@ -180,7 +180,8 @@ void Mangler::getNameWithPrefix(SmallVectorImpl<char> &OutName,
   ManglerPrefixTy PrefixTy = Mangler::Default;
   if (GV->hasPrivateLinkage() || isImplicitlyPrivate)
     PrefixTy = Mangler::Private;
-  else if (GV->hasLinkerPrivateLinkage() || GV->hasLinkerPrivateWeakLinkage())
+  else if (GV->hasLinkerPrivateLinkage() || GV->hasLinkerPrivateWeakLinkage() ||
+           GV->hasLinkerPrivateWeakDefAutoLinkage())
     PrefixTy = Mangler::LinkerPrivate;
   
   // If this global has a name, handle it simply.
diff --git a/llvm/lib/VMCore/AsmWriter.cpp b/llvm/lib/VMCore/AsmWriter.cpp
index c925a7e3391..c7f27c62639 100644
--- a/llvm/lib/VMCore/AsmWriter.cpp
+++ b/llvm/lib/VMCore/AsmWriter.cpp
@@ -1435,6 +1435,9 @@ static void PrintLinkage(GlobalValue::LinkageTypes LT,
   case GlobalValue::LinkerPrivateWeakLinkage:
     Out << "linker_private_weak ";
     break;
+  case GlobalValue::LinkerPrivateWeakDefAutoLinkage:
+    Out << "linker_private_weak_def_auto ";
+    break;
   case GlobalValue::InternalLinkage:      Out << "internal ";       break;
   case GlobalValue::LinkOnceAnyLinkage:   Out << "linkonce ";       break;
   case GlobalValue::LinkOnceODRLinkage:   Out << "linkonce_odr ";   break;
diff --git a/llvm/lib/VMCore/Core.cpp b/llvm/lib/VMCore/Core.cpp
index f458051c31c..e884404d8ac 100644
--- a/llvm/lib/VMCore/Core.cpp
+++ b/llvm/lib/VMCore/Core.cpp
@@ -1069,6 +1069,8 @@ LLVMLinkage LLVMGetLinkage(LLVMValueRef Global) {
     return LLVMLinkerPrivateLinkage;
   case GlobalValue::LinkerPrivateWeakLinkage:
     return LLVMLinkerPrivateWeakLinkage;
+  case GlobalValue::LinkerPrivateWeakDefAutoLinkage:
+    return LLVMLinkerPrivateWeakDefAutoLinkage;
   case GlobalValue::DLLImportLinkage:
     return LLVMDLLImportLinkage;
   case GlobalValue::DLLExportLinkage:
@@ -1122,6 +1124,9 @@ void LLVMSetLinkage(LLVMValueRef Global, LLVMLinkage Linkage) {
   case LLVMLinkerPrivateWeakLinkage:
     GV->setLinkage(GlobalValue::LinkerPrivateWeakLinkage);
     break;
+  case LLVMLinkerPrivateWeakDefAutoLinkage:
+    GV->setLinkage(GlobalValue::LinkerPrivateWeakDefAutoLinkage);
+    break;
   case LLVMDLLImportLinkage:
     GV->setLinkage(GlobalValue::DLLImportLinkage);
     break;
diff --git a/llvm/lib/VMCore/Verifier.cpp b/llvm/lib/VMCore/Verifier.cpp
index 8ff15514243..a3f1510887d 100644
--- a/llvm/lib/VMCore/Verifier.cpp
+++ b/llvm/lib/VMCore/Verifier.cpp
@@ -446,6 +446,10 @@ void Verifier::visitGlobalValue(GlobalValue &GV) {
     Assert1(GVar && GVar->getType()->getElementType()->isArrayTy(),
             "Only global arrays can have appending linkage!", GVar);
   }
+
+  Assert1(!GV.hasLinkerPrivateWeakDefAutoLinkage() || GV.hasDefaultVisibility(),
+          "linker_private_weak_def_auto can only have default visibility!",
+          &GV);
 }
 
 void Verifier::visitGlobalVariable(GlobalVariable &GV) {