Clean up handling of visibility.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@69027 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 59 insertions, 115 deletions

diff --git a/lib/CodeGen/CGObjCMac.cpp b/lib/CodeGen/CGObjCMac.cpp
index c69f5937d0..153c8681a0 100644
--- a/lib/CodeGen/CGObjCMac.cpp
+++ b/lib/CodeGen/CGObjCMac.cpp
@@ -440,8 +440,6 @@ protected:
   llvm::Constant *BuildIvarLayout(const ObjCImplementationDecl *OI,
                                   bool ForStrongLayout);
   
-  bool IsClassHidden(const ObjCInterfaceDecl *ID);
-  
   void BuildAggrIvarLayout(const ObjCInterfaceDecl *OI,
                            const llvm::StructLayout *Layout,
                            const RecordDecl *RD,
@@ -1441,23 +1439,6 @@ enum ClassFlags {
   eClassFlags_ABI2_HasCXXStructors = 0x00004   // <rdr://4923634>
 };
 
-bool CGObjCCommonMac::IsClassHidden(const ObjCInterfaceDecl *ID) {
-  if (const VisibilityAttr *attr = ID->getAttr<VisibilityAttr>()) {
-    switch (attr->getVisibility()) {
-    default: 
-      assert(0 && "Unknown visibility");
-      return false;
-    case VisibilityAttr::DefaultVisibility:
-    case VisibilityAttr::ProtectedVisibility:  // FIXME: What do we do here?
-      return false;
-    case VisibilityAttr::HiddenVisibility:
-      return true;
-    }
-  } else
-      return (CGM.getLangOptions().getVisibilityMode() ==
-              LangOptions::HiddenVisibility);
-}
-
 /*
   struct _objc_class {
     Class isa;
@@ -1494,7 +1475,7 @@ void CGObjCMac::GenerateClass(const ObjCImplementationDecl *ID) {
   unsigned Size = CGM.getTargetData().getTypePaddedSize(InterfaceTy);
 
   // FIXME: Set CXX-structors flag.
-  if (IsClassHidden(ID->getClassInterface()))
+  if (CGM.getDeclVisibilityMode(ID->getClassInterface()) == LangOptions::Hidden)
     Flags |= eClassFlags_Hidden;
 
   std::vector<llvm::Constant*> InstanceMethods, ClassMethods;
@@ -1571,7 +1552,7 @@ llvm::Constant *CGObjCMac::EmitMetaClass(const ObjCImplementationDecl *ID,
   unsigned Flags = eClassFlags_Meta;
   unsigned Size = CGM.getTargetData().getTypePaddedSize(ObjCTypes.ClassTy);
 
-  if (IsClassHidden(ID->getClassInterface()))
+  if (CGM.getDeclVisibilityMode(ID->getClassInterface()) == LangOptions::Hidden)
     Flags |= eClassFlags_Hidden;
  
   std::vector<llvm::Constant*> Values(12);
@@ -4226,7 +4207,8 @@ void CGObjCNonFragileABIMac::GenerateClass(const ObjCImplementationDecl *ID) {
   
   llvm::GlobalVariable *SuperClassGV, *IsAGV;
   
-  bool classIsHidden = IsClassHidden(ID->getClassInterface());
+  bool classIsHidden = 
+    CGM.getDeclVisibilityMode(ID->getClassInterface()) == LangOptions::Hidden;
   if (classIsHidden)
     flags |= OBJC2_CLS_HIDDEN;
   if (!ID->getClassInterface()->getSuperClass()) {
@@ -4547,13 +4529,10 @@ llvm::Constant * CGObjCNonFragileABIMac::EmitIvarOffsetVar(
     CGM.getTargetData().getPrefTypeAlignment(ObjCTypes.LongTy));
   // @private and @package have hidden visibility.
   bool globalVisibility = (Ivar->getAccessControl() == ObjCIvarDecl::Public ||
-                           Ivar->getAccessControl() == ObjCIvarDecl::Protected);  
-  if (!globalVisibility)
+                           Ivar->getAccessControl() == ObjCIvarDecl::Protected);
+  if (!globalVisibility || CGM.getDeclVisibilityMode(ID) == LangOptions::Hidden)
     IvarOffsetGV->setVisibility(llvm::GlobalValue::HiddenVisibility);
-  else if (IsClassHidden(ID))
-      IvarOffsetGV->setVisibility(llvm::GlobalValue::HiddenVisibility);
-  else if (CGM.getLangOptions().getVisibilityMode() == 
-           LangOptions::DefaultVisibility)
+  else
     IvarOffsetGV->setVisibility(llvm::GlobalValue::DefaultVisibility);
   IvarOffsetGV->setSection("__DATA, __objc_const");
   UsedGlobals.push_back(IvarOffsetGV);
@@ -5633,8 +5612,7 @@ CGObjCNonFragileABIMac::GetInterfaceEHType(const ObjCInterfaceDecl *ID,
                                      &CGM.getModule());
   }
 
-  if (CGM.getLangOptions().getVisibilityMode() ==
-      LangOptions::HiddenVisibility)
+  if (CGM.getLangOptions().getVisibilityMode() == LangOptions::Hidden)
     Entry->setVisibility(llvm::GlobalValue::HiddenVisibility);
   Entry->setAlignment(8);
 
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index 7dacc3bfce..855791a5d3 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -95,54 +95,45 @@ void CodeGenModule::ErrorUnsupported(const Decl *D, const char *Type,
   getDiags().Report(Context.getFullLoc(D->getLocation()), DiagID) << Msg;
 }
 
-/// setGlobalVisibility - Set the visibility for the given LLVM
-/// GlobalValue according to the given clang AST visibility value.
-static void setGlobalVisibility(llvm::GlobalValue *GV,
-                                VisibilityAttr::VisibilityTypes Vis) {
-  // Internal definitions should always have default visibility.
-  if (GV->hasLocalLinkage()) {
-    GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
-    return;
+LangOptions::VisibilityMode 
+CodeGenModule::getDeclVisibilityMode(const Decl *D) const {
+  if (const VarDecl *VD = dyn_cast<VarDecl>(D))
+    if (VD->getStorageClass() == VarDecl::PrivateExtern)
+      return LangOptions::Hidden;
+
+  if (const VisibilityAttr *attr = D->getAttr<VisibilityAttr>()) {
+    switch (attr->getVisibility()) {
+    default: assert(0 && "Unknown visibility!");
+    case VisibilityAttr::DefaultVisibility: 
+      return LangOptions::Default;
+    case VisibilityAttr::HiddenVisibility:
+      return LangOptions::Hidden;
+    case VisibilityAttr::ProtectedVisibility:
+      return LangOptions::Protected;
+    }
   }
 
-  switch (Vis) {
-  default: assert(0 && "Unknown visibility!");
-  case VisibilityAttr::DefaultVisibility:
-    GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
-    break;
-  case VisibilityAttr::HiddenVisibility:
-    GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
-    break;
-  case VisibilityAttr::ProtectedVisibility:
-    GV->setVisibility(llvm::GlobalValue::ProtectedVisibility);
-    break;
-  }
+  return getLangOptions().getVisibilityMode();
 }
 
-static void setGlobalOptionVisibility(llvm::GlobalValue *GV,
-                                      LangOptions::VisibilityMode Vis) {
-  // Internal definitions should always have default visibility.
+void CodeGenModule::setGlobalVisibility(llvm::GlobalValue *GV, 
+                                        const Decl *D) const {
+  // Internal definitions always have default visibility.
   if (GV->hasLocalLinkage()) {
     GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
     return;
   }
 
-  switch (Vis) {
+  switch (getDeclVisibilityMode(D)) {
   default: assert(0 && "Unknown visibility!");
-  case LangOptions::NonVisibility:
-    break;
-  case LangOptions::DefaultVisibility:
-    GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
-    break;
-  case LangOptions::HiddenVisibility:
-    GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
-    break;
-  case LangOptions::ProtectedVisibility:
-    GV->setVisibility(llvm::GlobalValue::ProtectedVisibility);
-    break;
+  case LangOptions::Default:
+    return GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
+  case LangOptions::Hidden:
+    return GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
+  case LangOptions::Protected:
+    return GV->setVisibility(llvm::GlobalValue::ProtectedVisibility);
   }
 }
-                                      
 
 /// \brief Retrieves the mangled name for the given declaration.
 ///
@@ -270,25 +261,18 @@ void CodeGenModule::SetGlobalValueAttributes(const Decl *D,
     GV->setLinkage(llvm::Function::WeakAnyLinkage);
   }
 
-  // FIXME: Figure out the relative priority of the attribute,
-  // -fvisibility, and private_extern.
   if (ForDefinition) {
-    if (const VisibilityAttr *attr = D->getAttr<VisibilityAttr>())
-      setGlobalVisibility(GV, attr->getVisibility());
-    else
-      setGlobalOptionVisibility(GV, getLangOptions().getVisibilityMode());
-  }
+    setGlobalVisibility(GV, D);
 
-  if (const SectionAttr *SA = D->getAttr<SectionAttr>())
-    GV->setSection(SA->getName());
-
-  // Only add to llvm.used when we see a definition, otherwise we
-  // might add multiple times or risk the value being replaced by a
-  // subsequent RAUW.
-  if (ForDefinition) {
+    // Only add to llvm.used when we see a definition, otherwise we
+    // might add multiple times or risk the value being replaced by a
+    // subsequent RAUW.
     if (D->hasAttr<UsedAttr>())
       AddUsedGlobal(GV);
   }
+
+  if (const SectionAttr *SA = D->getAttr<SectionAttr>())
+    GV->setSection(SA->getName());
 }
 
 void CodeGenModule::SetFunctionAttributes(const Decl *D,
@@ -645,7 +629,7 @@ llvm::Constant *CodeGenModule::GetOrCreateLLVMGlobal(const char *MangledName,
 
     // FIXME: Merge with other attribute handling code.
     if (D->getStorageClass() == VarDecl::PrivateExtern)
-      setGlobalVisibility(GV, VisibilityAttr::HiddenVisibility);
+      GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
 
     if (D->hasAttr<WeakAttr>() || D->hasAttr<WeakImportAttr>())
       GV->setLinkage(llvm::GlobalValue::ExternalWeakLinkage);
@@ -746,10 +730,6 @@ void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) {
   // "extern int x[];") and then a definition of a different type (e.g.
   // "int x[10];"). This also happens when an initializer has a different type
   // from the type of the global (this happens with unions).
-  //
-  // FIXME: This also ends up happening if there's a definition followed by
-  // a tentative definition!  (Although Sema rejects that construct
-  // at the moment.)
   if (GV == 0 ||
       GV->getType()->getElementType() != InitType ||
       GV->getType()->getAddressSpace() != ASTTy.getAddressSpace()) {
@@ -789,42 +769,20 @@ void CodeGenModule::EmitGlobalVarDefinition(const VarDecl *D) {
     GV->setLinkage(llvm::Function::DLLExportLinkage);
   else if (D->hasAttr<WeakAttr>() || D->hasAttr<WeakImportAttr>())
     GV->setLinkage(llvm::GlobalVariable::WeakAnyLinkage);
-  else {
-    // FIXME: This isn't right.  This should handle common linkage and other
-    // stuff.
-    switch (D->getStorageClass()) {
-    case VarDecl::Static: assert(0 && "This case handled above");
-    case VarDecl::Auto:
-    case VarDecl::Register:
-      assert(0 && "Can't have auto or register globals");
-    case VarDecl::None:
-      if (!D->getInit() && !CompileOpts.NoCommon)
-        GV->setLinkage(llvm::GlobalVariable::CommonLinkage);
-      else
-        GV->setLinkage(llvm::GlobalVariable::ExternalLinkage);
-      break;
-    case VarDecl::Extern:
-      // FIXME: common
-      break;
-      
-    case VarDecl::PrivateExtern:
-      GV->setVisibility(llvm::GlobalValue::HiddenVisibility);
-      // FIXME: common
-      break;
-    }
-  }
-
-  if (const VisibilityAttr *attr = D->getAttr<VisibilityAttr>())
-    setGlobalVisibility(GV, attr->getVisibility());
+  else if (!CompileOpts.NoCommon &&
+           (!D->hasExternalStorage() && !D->getInit()))
+    GV->setLinkage(llvm::GlobalVariable::CommonLinkage);
   else
-    setGlobalOptionVisibility(GV, getLangOptions().getVisibilityMode());
+    GV->setLinkage(llvm::GlobalVariable::ExternalLinkage);
 
-  if (const SectionAttr *SA = D->getAttr<SectionAttr>())
-    GV->setSection(SA->getName());
+  setGlobalVisibility(GV, D);
 
   if (D->hasAttr<UsedAttr>())
     AddUsedGlobal(GV);
 
+  if (const SectionAttr *SA = D->getAttr<SectionAttr>())
+    GV->setSection(SA->getName());
+
   // Emit global variable debug information.
   if (CGDebugInfo *DI = getDebugInfo()) {
     DI->setLocation(D->getLocation());
diff --git a/lib/CodeGen/CodeGenModule.h b/lib/CodeGen/CodeGenModule.h
index a1e2efc439..b2e6e228e0 100644
--- a/lib/CodeGen/CodeGenModule.h
+++ b/lib/CodeGen/CodeGenModule.h
@@ -14,6 +14,7 @@
 #ifndef CLANG_CODEGEN_CODEGENMODULE_H
 #define CLANG_CODEGEN_CODEGENMODULE_H
 
+#include "clang/Basic/LangOptions.h"
 #include "clang/AST/Attr.h"
 #include "CGBlocks.h"
 #include "CGCall.h"
@@ -167,6 +168,13 @@ public:
   Diagnostic &getDiags() const { return Diags; }
   const llvm::TargetData &getTargetData() const { return TheTargetData; }
 
+  /// getDeclVisibilityMode - Compute the visibility of the decl \arg D.
+  LangOptions::VisibilityMode getDeclVisibilityMode(const Decl *D) const;
+
+  /// setGlobalVisibility - Set the visibility for the given LLVM
+  /// GlobalValue.
+  void setGlobalVisibility(llvm::GlobalValue *GV, const Decl *D) const;
+
   /// GetAddrOfGlobalVar - Return the llvm::Constant for the address of the
   /// given global variable.  If Ty is non-null and if the global doesn't exist,
   /// then it will be greated with the specified type instead of whatever the