* PIC codegen for X86/Linux has been implemented

* PIC-aware internal structures in X86 Codegen have been refactored
* Visibility (default/weak) has been added
* Docs fixes (external weak linkage, visibility, formatting)


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33136 91177308-0d34-0410-b5e6-96231b3b80d8

19 files changed, 358 insertions, 143 deletions

diff --git a/lib/AsmParser/Lexer.l b/lib/AsmParser/Lexer.l
index 5300b3dabe..22fe64bf0d 100644
--- a/lib/AsmParser/Lexer.l
+++ b/lib/AsmParser/Lexer.l
@@ -203,6 +203,7 @@ weak            { return WEAK; }
 appending       { return APPENDING; }
 dllimport       { return DLLIMPORT; }
 dllexport       { return DLLEXPORT; }
+hidden          { return HIDDEN; }
 extern_weak     { return EXTERN_WEAK; }
 external        { return EXTERNAL; }
 implementation  { return IMPLEMENTATION; }
diff --git a/lib/AsmParser/Lexer.l.cvs b/lib/AsmParser/Lexer.l.cvs
index 5300b3dabe..22fe64bf0d 100644
--- a/lib/AsmParser/Lexer.l.cvs
+++ b/lib/AsmParser/Lexer.l.cvs
@@ -203,6 +203,7 @@ weak            { return WEAK; }
 appending       { return APPENDING; }
 dllimport       { return DLLIMPORT; }
 dllexport       { return DLLEXPORT; }
+hidden          { return HIDDEN; }
 extern_weak     { return EXTERN_WEAK; }
 external        { return EXTERNAL; }
 implementation  { return IMPLEMENTATION; }
diff --git a/lib/AsmParser/llvmAsmParser.y b/lib/AsmParser/llvmAsmParser.y
index b84cf25150..52d8847d32 100644
--- a/lib/AsmParser/llvmAsmParser.y
+++ b/lib/AsmParser/llvmAsmParser.y
@@ -210,6 +210,7 @@ static struct PerFunctionInfo {
   std::map<const Type*, ValueList> LateResolveValues;
   bool isDeclare;                    // Is this function a forward declararation?
   GlobalValue::LinkageTypes Linkage; // Linkage for forward declaration.
+  GlobalValue::VisibilityTypes Visibility;
 
   /// BBForwardRefs - When we see forward references to basic blocks, keep
   /// track of them here.
@@ -220,7 +221,8 @@ static struct PerFunctionInfo {
   inline PerFunctionInfo() {
     CurrentFunction = 0;
     isDeclare = false;
-    Linkage = GlobalValue::ExternalLinkage;    
+    Linkage = GlobalValue::ExternalLinkage;
+    Visibility = GlobalValue::DefaultVisibility;
   }
 
   inline void FunctionStart(Function *M) {
@@ -245,6 +247,7 @@ static struct PerFunctionInfo {
     CurrentFunction = 0;
     isDeclare = false;
     Linkage = GlobalValue::ExternalLinkage;
+    Visibility = GlobalValue::DefaultVisibility;
   }
 } CurFun;  // Info for the current function...
 
@@ -648,7 +651,9 @@ static void setValueName(Value *V, char *NameStr) {
 /// ParseGlobalVariable - Handle parsing of a global.  If Initializer is null,
 /// this is a declaration, otherwise it is a definition.
 static GlobalVariable *
-ParseGlobalVariable(char *NameStr,GlobalValue::LinkageTypes Linkage,
+ParseGlobalVariable(char *NameStr,
+                    GlobalValue::LinkageTypes Linkage,
+                    GlobalValue::VisibilityTypes Visibility,
                     bool isConstantGlobal, const Type *Ty,
                     Constant *Initializer) {
   if (isa<FunctionType>(Ty)) {
@@ -681,6 +686,7 @@ ParseGlobalVariable(char *NameStr,GlobalValue::LinkageTypes Linkage,
     CurModule.CurrentModule->getGlobalList().push_back(GV);
     GV->setInitializer(Initializer);
     GV->setLinkage(Linkage);
+    GV->setVisibility(Visibility);
     GV->setConstant(isConstantGlobal);
     InsertValue(GV, CurModule.Values);
     return GV;
@@ -702,6 +708,7 @@ ParseGlobalVariable(char *NameStr,GlobalValue::LinkageTypes Linkage,
   GlobalVariable *GV =
     new GlobalVariable(Ty, isConstantGlobal, Linkage, Initializer, Name,
                        CurModule.CurrentModule);
+  GV->setVisibility(Visibility);
   InsertValue(GV, CurModule.Values);
   return GV;
 }
@@ -898,6 +905,7 @@ Module *llvm::RunVMAsmParser(const char * AsmString, Module * M) {
   std::vector<llvm::Constant*>           *ConstVector;
 
   llvm::GlobalValue::LinkageTypes         Linkage;
+  llvm::GlobalValue::VisibilityTypes      Visibility;
   llvm::FunctionType::ParameterAttributes ParamAttrs;
   int64_t                           SInt64Val;
   uint64_t                          UInt64Val;
@@ -940,6 +948,7 @@ Module *llvm::RunVMAsmParser(const char * AsmString, Module * M) {
 %type <BoolVal>       OptSideEffect               // 'sideeffect' or not.
 %type <Linkage>       GVInternalLinkage GVExternalLinkage
 %type <Linkage>       FunctionDefineLinkage FunctionDeclareLinkage
+%type <Visibility>    GVVisibilityStyle
 %type <Endianness>    BigOrLittle
 
 // ValueRef - Unresolved reference to a definition or BB
@@ -1011,6 +1020,9 @@ Module *llvm::RunVMAsmParser(const char * AsmString, Module * M) {
 // Function Attributes
 %token NORETURN
 
+// Visibility Styles
+%token DEFAULT HIDDEN
+
 %start Module
 %%
 
@@ -1081,6 +1093,11 @@ GVExternalLinkage
   | EXTERNAL    { $$ = GlobalValue::ExternalLinkage; }
   ;
 
+GVVisibilityStyle
+  : /*empty*/ { $$ = GlobalValue::DefaultVisibility; }
+  | HIDDEN    { $$ = GlobalValue::HiddenVisibility;  }
+  ;
+
 FunctionDeclareLinkage
   : /*empty*/   { $$ = GlobalValue::ExternalLinkage; }
   | DLLIMPORT   { $$ = GlobalValue::DLLImportLinkage; } 
@@ -1225,7 +1242,7 @@ Types
     if (isVarArg) Params.pop_back();
 
     FunctionType *FT = FunctionType::get(*$1, Params, isVarArg, Attrs);
-    delete $3;      // Delete the argument list
+    delete $3;   // Delete the argument list
     delete $1;   // Delete the return type handle
     $$ = new PATypeHolder(HandleUpRefs(FT)); 
     CHECK_FOR_ERROR
@@ -1883,29 +1900,29 @@ Definition
     }
     CHECK_FOR_ERROR
   }
-  | OptAssign GlobalType ConstVal { /* "Externally Visible" Linkage */
-    if ($3 == 0) 
+  | OptAssign GVVisibilityStyle GlobalType ConstVal { /* "Externally Visible" Linkage */
+    if ($4 == 0) 
       GEN_ERROR("Global value initializer is not a constant!");
-    CurGV = ParseGlobalVariable($1, GlobalValue::ExternalLinkage, $2, 
-                                $3->getType(), $3);
+    CurGV = ParseGlobalVariable($1, GlobalValue::ExternalLinkage,
+                                $2, $3, $4->getType(), $4);
     CHECK_FOR_ERROR
   } GlobalVarAttributes {
     CurGV = 0;
   }
-  | OptAssign GVInternalLinkage GlobalType ConstVal {
-    if ($4 == 0) 
+  | OptAssign GVInternalLinkage GVVisibilityStyle GlobalType ConstVal {
+    if ($5 == 0) 
       GEN_ERROR("Global value initializer is not a constant!");
-    CurGV = ParseGlobalVariable($1, $2, $3, $4->getType(), $4);
+    CurGV = ParseGlobalVariable($1, $2, $3, $4, $5->getType(), $5);
     CHECK_FOR_ERROR
   } GlobalVarAttributes {
     CurGV = 0;
   }
-  | OptAssign GVExternalLinkage GlobalType Types {
+  | OptAssign GVExternalLinkage GVVisibilityStyle GlobalType Types {
     if (!UpRefs.empty())
-      GEN_ERROR("Invalid upreference in type: " + (*$4)->getDescription());
-    CurGV = ParseGlobalVariable($1, $2, $3, *$4, 0);
+      GEN_ERROR("Invalid upreference in type: " + (*$5)->getDescription());
+    CurGV = ParseGlobalVariable($1, $2, $3, $4, *$5, 0);
     CHECK_FOR_ERROR
-    delete $4;
+    delete $5;
   } GlobalVarAttributes {
     CurGV = 0;
     CHECK_FOR_ERROR
@@ -2103,6 +2120,7 @@ FunctionHeaderH : OptCallingConv ResultTypes Name '(' ArgList ')'
     // correctly handle cases, when pointer to function is passed as argument to
     // another function.
     Fn->setLinkage(CurFun.Linkage);
+    Fn->setVisibility(CurFun.Visibility);
   }
   Fn->setCallingConv($1);
   Fn->setAlignment($9);
@@ -2136,12 +2154,13 @@ FunctionHeaderH : OptCallingConv ResultTypes Name '(' ArgList ')'
 
 BEGIN : BEGINTOK | '{';                // Allow BEGIN or '{' to start a function
 
-FunctionHeader : FunctionDefineLinkage FunctionHeaderH BEGIN {
+FunctionHeader : FunctionDefineLinkage GVVisibilityStyle FunctionHeaderH BEGIN {
   $$ = CurFun.CurrentFunction;
 
   // Make sure that we keep track of the linkage type even if there was a
   // previous "declare".
   $$->setLinkage($1);
+  $$->setVisibility($2);
 };
 
 END : ENDTOK | '}';                    // Allow end of '}' to end a function
@@ -2151,8 +2170,9 @@ Function : BasicBlockList END {
   CHECK_FOR_ERROR
 };
 
-FunctionProto : FunctionDeclareLinkage FunctionHeaderH {
+FunctionProto : FunctionDeclareLinkage GVVisibilityStyle FunctionHeaderH {
     CurFun.CurrentFunction->setLinkage($1);
+    CurFun.CurrentFunction->setVisibility($2);
     $$ = CurFun.CurrentFunction;
     CurFun.FunctionDone();
     CHECK_FOR_ERROR
diff --git a/lib/AsmParser/llvmAsmParser.y.cvs b/lib/AsmParser/llvmAsmParser.y.cvs
index b84cf25150..52d8847d32 100644
--- a/lib/AsmParser/llvmAsmParser.y.cvs
+++ b/lib/AsmParser/llvmAsmParser.y.cvs
@@ -210,6 +210,7 @@ static struct PerFunctionInfo {
   std::map<const Type*, ValueList> LateResolveValues;
   bool isDeclare;                    // Is this function a forward declararation?
   GlobalValue::LinkageTypes Linkage; // Linkage for forward declaration.
+  GlobalValue::VisibilityTypes Visibility;
 
   /// BBForwardRefs - When we see forward references to basic blocks, keep
   /// track of them here.
@@ -220,7 +221,8 @@ static struct PerFunctionInfo {
   inline PerFunctionInfo() {
     CurrentFunction = 0;
     isDeclare = false;
-    Linkage = GlobalValue::ExternalLinkage;    
+    Linkage = GlobalValue::ExternalLinkage;
+    Visibility = GlobalValue::DefaultVisibility;
   }
 
   inline void FunctionStart(Function *M) {
@@ -245,6 +247,7 @@ static struct PerFunctionInfo {
     CurrentFunction = 0;
     isDeclare = false;
     Linkage = GlobalValue::ExternalLinkage;
+    Visibility = GlobalValue::DefaultVisibility;
   }
 } CurFun;  // Info for the current function...
 
@@ -648,7 +651,9 @@ static void setValueName(Value *V, char *NameStr) {
 /// ParseGlobalVariable - Handle parsing of a global.  If Initializer is null,
 /// this is a declaration, otherwise it is a definition.
 static GlobalVariable *
-ParseGlobalVariable(char *NameStr,GlobalValue::LinkageTypes Linkage,
+ParseGlobalVariable(char *NameStr,
+                    GlobalValue::LinkageTypes Linkage,
+                    GlobalValue::VisibilityTypes Visibility,
                     bool isConstantGlobal, const Type *Ty,
                     Constant *Initializer) {
   if (isa<FunctionType>(Ty)) {
@@ -681,6 +686,7 @@ ParseGlobalVariable(char *NameStr,GlobalValue::LinkageTypes Linkage,
     CurModule.CurrentModule->getGlobalList().push_back(GV);
     GV->setInitializer(Initializer);
     GV->setLinkage(Linkage);
+    GV->setVisibility(Visibility);
     GV->setConstant(isConstantGlobal);
     InsertValue(GV, CurModule.Values);
     return GV;
@@ -702,6 +708,7 @@ ParseGlobalVariable(char *NameStr,GlobalValue::LinkageTypes Linkage,
   GlobalVariable *GV =
     new GlobalVariable(Ty, isConstantGlobal, Linkage, Initializer, Name,
                        CurModule.CurrentModule);
+  GV->setVisibility(Visibility);
   InsertValue(GV, CurModule.Values);
   return GV;
 }
@@ -898,6 +905,7 @@ Module *llvm::RunVMAsmParser(const char * AsmString, Module * M) {
   std::vector<llvm::Constant*>           *ConstVector;
 
   llvm::GlobalValue::LinkageTypes         Linkage;
+  llvm::GlobalValue::VisibilityTypes      Visibility;
   llvm::FunctionType::ParameterAttributes ParamAttrs;
   int64_t                           SInt64Val;
   uint64_t                          UInt64Val;
@@ -940,6 +948,7 @@ Module *llvm::RunVMAsmParser(const char * AsmString, Module * M) {
 %type <BoolVal>       OptSideEffect               // 'sideeffect' or not.
 %type <Linkage>       GVInternalLinkage GVExternalLinkage
 %type <Linkage>       FunctionDefineLinkage FunctionDeclareLinkage
+%type <Visibility>    GVVisibilityStyle
 %type <Endianness>    BigOrLittle
 
 // ValueRef - Unresolved reference to a definition or BB
@@ -1011,6 +1020,9 @@ Module *llvm::RunVMAsmParser(const char * AsmString, Module * M) {
 // Function Attributes
 %token NORETURN
 
+// Visibility Styles
+%token DEFAULT HIDDEN
+
 %start Module
 %%
 
@@ -1081,6 +1093,11 @@ GVExternalLinkage
   | EXTERNAL    { $$ = GlobalValue::ExternalLinkage; }
   ;
 
+GVVisibilityStyle
+  : /*empty*/ { $$ = GlobalValue::DefaultVisibility; }
+  | HIDDEN    { $$ = GlobalValue::HiddenVisibility;  }
+  ;
+
 FunctionDeclareLinkage
   : /*empty*/   { $$ = GlobalValue::ExternalLinkage; }
   | DLLIMPORT   { $$ = GlobalValue::DLLImportLinkage; } 
@@ -1225,7 +1242,7 @@ Types
     if (isVarArg) Params.pop_back();
 
     FunctionType *FT = FunctionType::get(*$1, Params, isVarArg, Attrs);
-    delete $3;      // Delete the argument list
+    delete $3;   // Delete the argument list
     delete $1;   // Delete the return type handle
     $$ = new PATypeHolder(HandleUpRefs(FT)); 
     CHECK_FOR_ERROR
@@ -1883,29 +1900,29 @@ Definition
     }
     CHECK_FOR_ERROR
   }
-  | OptAssign GlobalType ConstVal { /* "Externally Visible" Linkage */
-    if ($3 == 0) 
+  | OptAssign GVVisibilityStyle GlobalType ConstVal { /* "Externally Visible" Linkage */
+    if ($4 == 0) 
       GEN_ERROR("Global value initializer is not a constant!");
-    CurGV = ParseGlobalVariable($1, GlobalValue::ExternalLinkage, $2, 
-                                $3->getType(), $3);
+    CurGV = ParseGlobalVariable($1, GlobalValue::ExternalLinkage,
+                                $2, $3, $4->getType(), $4);
     CHECK_FOR_ERROR
   } GlobalVarAttributes {
     CurGV = 0;
   }
-  | OptAssign GVInternalLinkage GlobalType ConstVal {
-    if ($4 == 0) 
+  | OptAssign GVInternalLinkage GVVisibilityStyle GlobalType ConstVal {
+    if ($5 == 0) 
       GEN_ERROR("Global value initializer is not a constant!");
-    CurGV = ParseGlobalVariable($1, $2, $3, $4->getType(), $4);
+    CurGV = ParseGlobalVariable($1, $2, $3, $4, $5->getType(), $5);
     CHECK_FOR_ERROR
   } GlobalVarAttributes {
     CurGV = 0;
   }
-  | OptAssign GVExternalLinkage GlobalType Types {
+  | OptAssign GVExternalLinkage GVVisibilityStyle GlobalType Types {
     if (!UpRefs.empty())
-      GEN_ERROR("Invalid upreference in type: " + (*$4)->getDescription());
-    CurGV = ParseGlobalVariable($1, $2, $3, *$4, 0);
+      GEN_ERROR("Invalid upreference in type: " + (*$5)->getDescription());
+    CurGV = ParseGlobalVariable($1, $2, $3, $4, *$5, 0);
     CHECK_FOR_ERROR
-    delete $4;
+    delete $5;
   } GlobalVarAttributes {
     CurGV = 0;
     CHECK_FOR_ERROR
@@ -2103,6 +2120,7 @@ FunctionHeaderH : OptCallingConv ResultTypes Name '(' ArgList ')'
     // correctly handle cases, when pointer to function is passed as argument to
     // another function.
     Fn->setLinkage(CurFun.Linkage);
+    Fn->setVisibility(CurFun.Visibility);
   }
   Fn->setCallingConv($1);
   Fn->setAlignment($9);
@@ -2136,12 +2154,13 @@ FunctionHeaderH : OptCallingConv ResultTypes Name '(' ArgList ')'
 
 BEGIN : BEGINTOK | '{';                // Allow BEGIN or '{' to start a function
 
-FunctionHeader : FunctionDefineLinkage FunctionHeaderH BEGIN {
+FunctionHeader : FunctionDefineLinkage GVVisibilityStyle FunctionHeaderH BEGIN {
   $$ = CurFun.CurrentFunction;
 
   // Make sure that we keep track of the linkage type even if there was a
   // previous "declare".
   $$->setLinkage($1);
+  $$->setVisibility($2);
 };
 
 END : ENDTOK | '}';                    // Allow end of '}' to end a function
@@ -2151,8 +2170,9 @@ Function : BasicBlockList END {
   CHECK_FOR_ERROR
 };
 
-FunctionProto : FunctionDeclareLinkage FunctionHeaderH {
+FunctionProto : FunctionDeclareLinkage GVVisibilityStyle FunctionHeaderH {
     CurFun.CurrentFunction->setLinkage($1);
+    CurFun.CurrentFunction->setVisibility($2);
     $$ = CurFun.CurrentFunction;
     CurFun.FunctionDone();
     CHECK_FOR_ERROR
diff --git a/lib/Bytecode/Reader/Analyzer.cpp b/lib/Bytecode/Reader/Analyzer.cpp
index 899a534272..465e3b053e 100644
--- a/lib/Bytecode/Reader/Analyzer.cpp
+++ b/lib/Bytecode/Reader/Analyzer.cpp
@@ -162,6 +162,7 @@ public:
     const Type* ElemType,
     bool isConstant,
     GlobalValue::LinkageTypes Linkage,
+    GlobalValue::VisibilityTypes Visibility,
     unsigned SlotNum,
     unsigned initSlot
   ) {
@@ -169,7 +170,9 @@ public:
       *os << "      GV: "
           << ( initSlot == 0 ? "Uni" : "I" ) << "nitialized, "
           << ( isConstant? "Constant, " : "Variable, ")
-          << " Linkage=" << Linkage << " Type=";
+          << " Linkage=" << Linkage
+          << " Visibility="<< Visibility
+          << " Type=";
       WriteTypeSymbolic(*os, ElemType, M);
       *os << " Slot=" << SlotNum << " InitSlot=" << initSlot
           << "\n";
@@ -206,6 +209,7 @@ public:
       *os << "      Function Decl: ";
       WriteTypeSymbolic(*os,Func->getType(),M);
       *os <<", Linkage=" << Func->getLinkage();
+      *os <<", Visibility=" << Func->getVisibility();
       *os << "\n";
     }
   }
@@ -311,6 +315,7 @@ public:
     if (os) {
       *os << "    BLOCK: Function {\n"
           << "      Linkage: " << Func->getLinkage() << "\n"
+          << "      Visibility: " << Func->getVisibility() << "\n"
           << "      Type: ";
       WriteTypeSymbolic(*os,Func->getType(),M);
       *os << "\n";
diff --git a/lib/Bytecode/Reader/Reader.cpp b/lib/Bytecode/Reader/Reader.cpp
index ce3826cb24..b91604acd7 100644
--- a/lib/Bytecode/Reader/Reader.cpp
+++ b/lib/Bytecode/Reader/Reader.cpp
@@ -1628,9 +1628,12 @@ void BytecodeReader::ParseFunctionBody(Function* F) {
 
   unsigned FuncSize = BlockEnd - At;
   GlobalValue::LinkageTypes Linkage = GlobalValue::ExternalLinkage;
+  GlobalValue::VisibilityTypes Visibility = GlobalValue::DefaultVisibility;
 
-  unsigned LinkageType = read_vbr_uint();
-  switch (LinkageType) {
+  unsigned rWord = read_vbr_uint();
+  unsigned LinkageID =  rWord & 65535;
+  unsigned VisibilityID = rWord >> 16;
+  switch (LinkageID) {
   case 0: Linkage = GlobalValue::ExternalLinkage; break;
   case 1: Linkage = GlobalValue::WeakLinkage; break;
   case 2: Linkage = GlobalValue::AppendingLinkage; break;
@@ -1644,8 +1647,17 @@ void BytecodeReader::ParseFunctionBody(Function* F) {
     Linkage = GlobalValue::InternalLinkage;
     break;
   }
+  switch (VisibilityID) {
+  case 0: Visibility = GlobalValue::DefaultVisibility; break;
+  case 1: Visibility = GlobalValue::HiddenVisibility; break;
+  default:
+   error("Unknown visibility type: " + utostr(VisibilityID));
+   Visibility = GlobalValue::DefaultVisibility;
+   break;
+  }
 
   F->setLinkage(Linkage);
+  F->setVisibility(Visibility);
   if (Handler) Handler->handleFunctionBegin(F,FuncSize);
 
   // Keep track of how many basic blocks we have read in...
@@ -1844,6 +1856,7 @@ void BytecodeReader::ParseModuleGlobalInfo() {
     // Linkage, bit4+ = slot#
     unsigned SlotNo = VarType >> 5;
     unsigned LinkageID = (VarType >> 2) & 7;
+    unsigned VisibilityID = 0;
     bool isConstant = VarType & 1;
     bool hasInitializer = (VarType & 2) != 0;
     unsigned Alignment = 0;
@@ -1853,10 +1866,12 @@ void BytecodeReader::ParseModuleGlobalInfo() {
     if (LinkageID == 3 && !hasInitializer) {
       unsigned ExtWord = read_vbr_uint();
       // The extension word has this format: bit 0 = has initializer, bit 1-3 =
-      // linkage, bit 4-8 = alignment (log2), bits 10+ = future use.
+      // linkage, bit 4-8 = alignment (log2), bit 9 = has section,
+      // bits 10-12 = visibility, bits 13+ = future use.
       hasInitializer = ExtWord & 1;
       LinkageID = (ExtWord >> 1) & 7;
       Alignment = (1 << ((ExtWord >> 4) & 31)) >> 1;
+      VisibilityID = (ExtWord >> 10) & 7;
       
       if (ExtWord & (1 << 9))  // Has a section ID.
         GlobalSectionID = read_vbr_uint();
@@ -1877,7 +1892,16 @@ void BytecodeReader::ParseModuleGlobalInfo() {
       Linkage = GlobalValue::InternalLinkage;
       break;
     }
-
+    GlobalValue::VisibilityTypes Visibility;
+    switch (VisibilityID) {
+    case 0: Visibility = GlobalValue::DefaultVisibility; break;
+    case 1: Visibility = GlobalValue::HiddenVisibility; break;
+    default:
+      error("Unknown visibility type: " + utostr(VisibilityID));
+      Visibility = GlobalValue::DefaultVisibility;
+      break;
+    }
+    
     const Type *Ty = getType(SlotNo);
     if (!Ty)
       error("Global has no type! SlotNo=" + utostr(SlotNo));
@@ -1891,6 +1915,7 @@ void BytecodeReader::ParseModuleGlobalInfo() {
     GlobalVariable *GV = new GlobalVariable(ElTy, isConstant, Linkage,
                                             0, "", TheModule);
     GV->setAlignment(Alignment);
+    GV->setVisibility(Visibility);
     insertValue(GV, SlotNo, ModuleValues);
 
     if (GlobalSectionID != 0)
@@ -1904,7 +1929,8 @@ void BytecodeReader::ParseModuleGlobalInfo() {
 
     // Notify handler about the global value.
     if (Handler)
-      Handler->handleGlobalVariable(ElTy, isConstant, Linkage, SlotNo,initSlot);
+      Handler->handleGlobalVariable(ElTy, isConstant, Linkage, Visibility,
+                                    SlotNo, initSlot);
 
     // Get next item
     VarType = read_vbr_uint();
diff --git a/lib/Bytecode/Writer/Writer.cpp b/lib/Bytecode/Writer/Writer.cpp
index c7003cdd7f..10a151d19c 100644
--- a/lib/Bytecode/Writer/Writer.cpp
+++ b/lib/Bytecode/Writer/Writer.cpp
@@ -960,6 +960,14 @@ static unsigned getEncodedLinkage(const GlobalValue *GV) {
   }
 }
 
+static unsigned getEncodedVisibility(const GlobalValue *GV) {
+  switch (GV->getVisibility()) {
+  default: assert(0 && "Invalid visibility!");
+  case GlobalValue::DefaultVisibility: return 0;
+  case GlobalValue::HiddenVisibility:  return 1;
+  }
+}
+
 void BytecodeWriter::outputModuleInfoBlock(const Module *M) {
   BytecodeBlock ModuleInfoBlock(BytecodeFormat::ModuleGlobalInfoBlockID, *this);
 
@@ -979,7 +987,9 @@ void BytecodeWriter::outputModuleInfoBlock(const Module *M) {
     
     // Fields: bit0 = isConstant, bit1 = hasInitializer, bit2-4=Linkage,
     // bit5+ = Slot # for type.
-    bool HasExtensionWord = (I->getAlignment() != 0) || I->hasSection();
+    bool HasExtensionWord = (I->getAlignment() != 0) ||
+                            I->hasSection() ||
+      (I->getVisibility() != GlobalValue::DefaultVisibility);
     
     // If we need to use the extension byte, set linkage=3(internal) and
     // initializer = 0 (impossible!).
@@ -993,12 +1003,13 @@ void BytecodeWriter::outputModuleInfoBlock(const Module *M) {
       output_vbr(oSlot);
       
       // The extension word has this format: bit 0 = has initializer, bit 1-3 =
-      // linkage, bit 4-8 = alignment (log2), bit 9 = has SectionID, 
-      // bits 10+ = future use.
+      // linkage, bit 4-8 = alignment (log2), bit 9 = has SectionID,
+      // bits 10-12 = visibility, bits 13+ = future use.
       unsigned ExtWord = (unsigned)I->hasInitializer() |
                          (getEncodedLinkage(I) << 1) |
                          ((Log2_32(I->getAlignment())+1) << 4) |
-                         ((unsigned)I->hasSection() << 9);
+                         ((unsigned)I->hasSection() << 9) |
+                         (getEncodedVisibility(I) << 10);
       output_vbr(ExtWord);
       if (I->hasSection()) {
         // Give section names unique ID's.
@@ -1102,7 +1113,8 @@ void BytecodeWriter::outputFunction(const Function *F) {
   if (F->isExternal()) return;
 
   BytecodeBlock FunctionBlock(BytecodeFormat::FunctionBlockID, *this);
-  output_vbr(getEncodedLinkage(F));
+  unsigned rWord = (getEncodedVisibility(F) << 16) | getEncodedLinkage(F);
+  output_vbr(rWord);
 
   // Get slot information about the function...
   Table.incorporateFunction(F);
diff --git a/lib/Target/CBackend/CBackend.cpp b/lib/Target/CBackend/CBackend.cpp
index a0b4ceb7f1..1346acbb04 100644
--- a/lib/Target/CBackend/CBackend.cpp
+++ b/lib/Target/CBackend/CBackend.cpp
@@ -1290,6 +1290,11 @@ static void generateCompilerSpecificCode(std::ostream& Out) {
       << "#define __ATTRIBUTE_WEAK__\n"
       << "#endif\n\n";
 
+  // Add hidden visibility support. FIXME: APPLE_CC?
+  Out << "#if defined(__GNUC__)\n"
+      << "#define __HIDDEN__ __attribute__((visibility(\"hidden\")))\n"
+      << "#endif\n\n";
+    
   // Define NaN and Inf as GCC builtins if using GCC, as 0 otherwise
   // From the GCC documentation:
   //
@@ -1500,6 +1505,8 @@ bool CWriter::doInitialization(Module &M) {
         Out << " __ATTRIBUTE_CTOR__";
       if (StaticDtors.count(I))
         Out << " __ATTRIBUTE_DTOR__";
+      if (I->hasHiddenVisibility())
+        Out << " __HIDDEN__";
       
       if (I->hasName() && I->getName()[0] == 1)
         Out << " LLVM_ASM(\"" << I->getName().c_str()+1 << "\")";
@@ -1531,6 +1538,8 @@ bool CWriter::doInitialization(Module &M) {
           Out << " __ATTRIBUTE_WEAK__";
         else if (I->hasExternalWeakLinkage())
           Out << " __EXTERNAL_WEAK__";
+        if (I->hasHiddenVisibility())
+          Out << " __HIDDEN__";
         Out << ";\n";
       }
   }
@@ -1559,6 +1568,9 @@ bool CWriter::doInitialization(Module &M) {
         else if (I->hasWeakLinkage())
           Out << " __ATTRIBUTE_WEAK__";
 
+        if (I->hasHiddenVisibility())
+          Out << " __HIDDEN__";
+        
         // If the initializer is not null, emit the initializer.  If it is null,
         // we try to avoid emitting large amounts of zeros.  The problem with
         // this, however, occurs when the variable has weak linkage.  In this
diff --git a/lib/Target/X86/README.txt b/lib/Target/X86/README.txt
index c871a76486..7e365203a8 100644
--- a/lib/Target/X86/README.txt
+++ b/lib/Target/X86/README.txt
@@ -534,10 +534,6 @@ do not make use of.
 
 //===---------------------------------------------------------------------===//
 
-We should handle __attribute__ ((__visibility__ ("hidden"))).
-
-//===---------------------------------------------------------------------===//
-
 int %foo(int* %a, int %t) {
 entry:
         br label %cond_true
diff --git a/lib/Target/X86/X86ATTAsmPrinter.cpp b/lib/Target/X86/X86ATTAsmPrinter.cpp
index ccc2965064..7edea6f074 100755
--- a/lib/Target/X86/X86ATTAsmPrinter.cpp
+++ b/lib/Target/X86/X86ATTAsmPrinter.cpp
@@ -19,6 +19,7 @@
 #include "X86MachineFunctionInfo.h"
 #include "X86TargetMachine.h"
 #include "X86TargetAsmInfo.h"
+#include "llvm/ADT/StringExtras.h"
 #include "llvm/CallingConv.h"
 #include "llvm/Module.h"
 #include "llvm/Support/Mangler.h"
@@ -29,6 +30,21 @@ using namespace llvm;
 
 STATISTIC(EmittedInsts, "Number of machine instrs printed");
 
+static std::string computePICLabel(unsigned fnNumber,
+                                   const X86Subtarget* Subtarget) 
+{
+  std::string label;
+
+  if (Subtarget->isTargetDarwin()) {
+    label =  "\"L" + utostr_32(fnNumber) + "$pb\"";
+  } else if (Subtarget->isTargetELF()) {
+    label = ".Lllvm$" + utostr_32(fnNumber) + "$piclabel";
+  } else
+    assert(0 && "Don't know how to print PIC label!\n");
+
+  return label;
+}
+
 /// getSectionForFunction - Return the section that we should emit the
 /// specified function body into.
 std::string X86ATTAsmPrinter::getSectionForFunction(const Function &F) const {
@@ -109,12 +125,15 @@ bool X86ATTAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
     }
     break;
   }
+  if (F->hasHiddenVisibility())
+    O << "\t.hidden " << CurrentFnName << "\n";
+  
   O << CurrentFnName << ":\n";
   // Add some workaround for linkonce linkage on Cygwin\MinGW
   if (Subtarget->isTargetCygMing() &&
       (F->getLinkage() == Function::LinkOnceLinkage ||
        F->getLinkage() == Function::WeakLinkage))
-    O << "_llvm$workaround$fake$stub_" << CurrentFnName << ":\n";
+    O << "Lllvm$workaround$fake$stub$" << CurrentFnName << ":\n";
 
   if (Subtarget->isTargetDarwin() ||
       Subtarget->isTargetELF() ||
@@ -193,9 +212,14 @@ void X86ATTAsmPrinter::printOperand(const MachineInstr *MI, unsigned OpNo,
     if (!isMemOp) O << '$';
     O << TAI->getPrivateGlobalPrefix() << "JTI" << getFunctionNumber() << "_"
       << MO.getJumpTableIndex();
-    if (X86PICStyle == PICStyle::Stub &&
-        TM.getRelocationModel() == Reloc::PIC_)
-      O << "-\"L" << getFunctionNumber() << "$pb\"";
+
+    if (TM.getRelocationModel() == Reloc::PIC_) {
+      if (Subtarget->isPICStyleStub())
+        O << "-\"L" << getFunctionNumber() << "$pb\"";
+      else if (Subtarget->isPICStyleGOT())
+        O << "@GOTOFF";
+    }
+    
     if (isMemOp && Subtarget->is64Bit() && !NotRIPRel)
       O << "(%rip)";
     return;
@@ -205,9 +229,14 @@ void X86ATTAsmPrinter::printOperand(const MachineInstr *MI, unsigned OpNo,
     if (!isMemOp) O << '$';
     O << TAI->getPrivateGlobalPrefix() << "CPI" << getFunctionNumber() << "_"
       << MO.getConstantPoolIndex();
-    if (X86PICStyle == PICStyle::Stub &&
-        TM.getRelocationModel() == Reloc::PIC_)
-      O << "-\"L" << getFunctionNumber() << "$pb\"";
+
+    if (TM.getRelocationModel() == Reloc::PIC_) {
+      if (Subtarget->isPICStyleStub())
+        O << "-\"L" << getFunctionNumber() << "$pb\"";
+      if (Subtarget->isPICStyleGOT())
+        O << "@GOTOFF";
+    }
+    
     int Offset = MO.getOffset();
     if (Offset > 0)
       O << "+" << Offset;
@@ -228,11 +257,11 @@ void X86ATTAsmPrinter::printOperand(const MachineInstr *MI, unsigned OpNo,
     
     bool isExt = (GV->isExternal() || GV->hasWeakLinkage() ||
                   GV->hasLinkOnceLinkage());
+    bool isHidden = GV->hasHiddenVisibility();
     
     X86SharedAsmPrinter::decorateName(Name, GV);
     
-    if (X86PICStyle == PICStyle::Stub &&
-        TM.getRelocationModel() != Reloc::Static) {
+    if (Subtarget->isPICStyleStub()) {
       // Link-once, External, or Weakly-linked global variables need
       // non-lazily-resolved stubs
       if (isExt) {
@@ -258,6 +287,12 @@ void X86ATTAsmPrinter::printOperand(const MachineInstr *MI, unsigned OpNo,
         O << "__imp_";          
       }       
       O << Name;
+
+      if (Subtarget->isPICStyleGOT() && isCallOp && isa<Function>(GV)) {
+        // Assemble call via PLT for non-local symbols
+        if (!isHidden || isExt)
+          O << "@PLT";
+      }
     }
 
     if (GV->hasExternalWeakLinkage())
@@ -269,31 +304,55 @@ void X86ATTAsmPrinter::printOperand(const MachineInstr *MI, unsigned OpNo,
     else if (Offset < 0)
       O << Offset;
 
-    if (isMemOp && Subtarget->is64Bit()) {
-      if (isExt && TM.getRelocationModel() != Reloc::Static)
-        O << "@GOTPCREL(%rip)";
-      else if (!NotRIPRel)
-        // Use rip when possible to reduce code size, except when index or
-        // base register are also part of the address. e.g.
-        // foo(%rip)(%rcx,%rax,4) is not legal
-        O << "(%rip)";        
+    if (isMemOp) {
+      if (isExt) {
+        if (Subtarget->isPICStyleGOT()) {
+          O << "@GOT";
+        } else if (Subtarget->isPICStyleRIPRel()) {
+          O << "@GOTPCREL(%rip)";
+        } if (Subtarget->is64Bit() && !NotRIPRel)
+            // Use rip when possible to reduce code size, except when
+            // index or base register are also part of the address. e.g.
+            // foo(%rip)(%rcx,%rax,4) is not legal
+            O << "(%rip)";