r281798 - CodeGen: refactor the ObjC cstring literal creation

[Saleem Abdulrasool via cfe-commits]

Author: compnerd
Date: Fri Sep 16 18:41:13 2016
New Revision: 281798

URL: http://llvm.org/viewvc/llvm-project?rev=281798&view=rev
Log:
CodeGen: refactor the ObjC cstring literal creation

This refactors the cstring literal creation as mentioned in the couple of FIXMEs
littered in the various invocations to CreateMetadataVar.  This centralises the
definition of the literals, and will enable changing the literal creation to a
single site.  NFC.

Modified:
    cfe/trunk/lib/CodeGen/CGObjCMac.cpp

Modified: cfe/trunk/lib/CodeGen/CGObjCMac.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGObjCMac.cpp?rev=281798&r1=281797&r2=281798&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/CGObjCMac.cpp (original)
+++ cfe/trunk/lib/CodeGen/CGObjCMac.cpp Fri Sep 16 18:41:13 2016
@@ -733,6 +733,13 @@ public:
   ObjCNonFragileABITypesHelper(CodeGen::CodeGenModule &cgm);
 };
 
+enum class ObjCLabelType {
+  ClassName,
+  MethodVarName,
+  MethodVarType,
+  PropertyName,
+};
+
 class CGObjCCommonMac : public CodeGen::CGObjCRuntime {
 public:
   class SKIP_SCAN {
@@ -1018,6 +1025,9 @@ public:
                                           StringRef Section, CharUnits Align,
                                           bool AddToUsed);
 
+  llvm::GlobalVariable *CreateCStringLiteral(StringRef Name,
+                                             ObjCLabelType LabelType);
+
 protected:
   CodeGen::RValue EmitMessageSend(CodeGen::CodeGenFunction &CGF,
                                   ReturnValueSlot Return,
@@ -3650,6 +3660,46 @@ llvm::GlobalVariable *CGObjCCommonMac::C
   return GV;
 }
 
+llvm::GlobalVariable *
+CGObjCCommonMac::CreateCStringLiteral(StringRef Name, ObjCLabelType Type) {
+  StringRef Label;
+  switch (Type) {
+  case ObjCLabelType::ClassName:     Label = "OBJC_CLASS_NAME_"; break;
+  case ObjCLabelType::MethodVarName: Label = "OBJC_METH_VAR_NAME_"; break;
+  case ObjCLabelType::MethodVarType: Label = "OBJC_METH_VAR_TYPE_"; break;
+  case ObjCLabelType::PropertyName:  Label = "OBJC_PROP_NAME_ATTR_"; break;
+  }
+
+  StringRef Section;
+  switch (Type) {
+  case ObjCLabelType::ClassName:
+    Section = isNonFragileABI() ? "__TEXT,__objc_classname,cstring_literals"
+                                : "__TEXT,__cstring,cstring_literals";
+    break;
+  case ObjCLabelType::MethodVarName:
+    Section = isNonFragileABI() ? "__TEXT,__objc_methname,cstring_literals"
+                                : "__TEXT,__cstring,cstring_literals";
+    break;
+  case ObjCLabelType::MethodVarType:
+    Section = isNonFragileABI() ? "__TEXT,__objc_methtype,cstring_literals"
+                                : "__TEXT,__cstring,cstring_literals";
+    break;
+  case ObjCLabelType::PropertyName:
+    Section = "__TEXT,__cstring,cstring_literals";
+    break;
+  }
+
+  llvm::Constant *Value = llvm::ConstantDataArray::getString(VMContext, Name);
+  llvm::GlobalVariable *GV =
+      new llvm::GlobalVariable(CGM.getModule(), Value->getType(), false,
+                               llvm::GlobalValue::PrivateLinkage, Value, Label);
+  GV->setSection(Section);
+  GV->setAlignment(CharUnits::One().getQuantity());
+  CGM.addCompilerUsedGlobal(GV);
+
+  return GV;
+}
+
 llvm::Function *CGObjCMac::ModuleInitFunction() {
   // Abuse this interface function as a place to finalize.
   FinishModule();
@@ -4707,12 +4757,7 @@ Address CGObjCMac::EmitSelectorAddr(Code
 llvm::Constant *CGObjCCommonMac::GetClassName(StringRef RuntimeName) {
     llvm::GlobalVariable *&Entry = ClassNames[RuntimeName];
     if (!Entry)
-      Entry = CreateMetadataVar(
-          "OBJC_CLASS_NAME_",
-          llvm::ConstantDataArray::getString(VMContext, RuntimeName),
-          ((ObjCABI == 2) ? "__TEXT,__objc_classname,cstring_literals"
-                          : "__TEXT,__cstring,cstring_literals"),
-          CharUnits::One(), true);
+      Entry = CreateCStringLiteral(RuntimeName, ObjCLabelType::ClassName);
     return getConstantGEP(VMContext, Entry, 0, 0);
 }
 
@@ -4960,14 +5005,8 @@ llvm::Constant *IvarLayoutBuilder::build
   // Null terminate the string.
   buffer.push_back(0);
 
-  bool isNonFragileABI = CGObjC.isNonFragileABI();
-
-  llvm::GlobalVariable *Entry = CGObjC.CreateMetadataVar(
-      "OBJC_CLASS_NAME_",
-      llvm::ConstantDataArray::get(CGM.getLLVMContext(), buffer),
-      (isNonFragileABI ? "__TEXT,__objc_classname,cstring_literals"
-                       : "__TEXT,__cstring,cstring_literals"),
-      CharUnits::One(), true);
+  auto *Entry = CGObjC.CreateCStringLiteral(
+      reinterpret_cast<char *>(buffer.data()), ObjCLabelType::ClassName);
   return getConstantGEP(CGM.getLLVMContext(), Entry, 0, 0);
 }
 
@@ -5062,16 +5101,9 @@ CGObjCCommonMac::BuildIvarLayout(const O
 
 llvm::Constant *CGObjCCommonMac::GetMethodVarName(Selector Sel) {
   llvm::GlobalVariable *&Entry = MethodVarNames[Sel];
-
   // FIXME: Avoid std::string in "Sel.getAsString()"
   if (!Entry)
-    Entry = CreateMetadataVar(
-        "OBJC_METH_VAR_NAME_",
-        llvm::ConstantDataArray::getString(VMContext, Sel.getAsString()),
-        ((ObjCABI == 2) ? "__TEXT,__objc_methname,cstring_literals"
-                        : "__TEXT,__cstring,cstring_literals"),
-        CharUnits::One(), true);
-
+    Entry = CreateCStringLiteral(Sel.getAsString(), ObjCLabelType::MethodVarName);
   return getConstantGEP(VMContext, Entry, 0, 0);
 }
 
@@ -5085,15 +5117,8 @@ llvm::Constant *CGObjCCommonMac::GetMeth
   CGM.getContext().getObjCEncodingForType(Field->getType(), TypeStr, Field);
 
   llvm::GlobalVariable *&Entry = MethodVarTypes[TypeStr];
-
   if (!Entry)
-    Entry = CreateMetadataVar(
-        "OBJC_METH_VAR_TYPE_",
-        llvm::ConstantDataArray::getString(VMContext, TypeStr),
-        ((ObjCABI == 2) ? "__TEXT,__objc_methtype,cstring_literals"
-                        : "__TEXT,__cstring,cstring_literals"),
-        CharUnits::One(), true);
-
+    Entry = CreateCStringLiteral(TypeStr, ObjCLabelType::MethodVarType);
   return getConstantGEP(VMContext, Entry, 0, 0);
 }
 
@@ -5104,28 +5129,16 @@ llvm::Constant *CGObjCCommonMac::GetMeth
     return nullptr;
 
   llvm::GlobalVariable *&Entry = MethodVarTypes[TypeStr];
-
   if (!Entry)
-    Entry = CreateMetadataVar(
-        "OBJC_METH_VAR_TYPE_",
-        llvm::ConstantDataArray::getString(VMContext, TypeStr),
-        ((ObjCABI == 2) ? "__TEXT,__objc_methtype,cstring_literals"
-                        : "__TEXT,__cstring,cstring_literals"),
-        CharUnits::One(), true);
-
+    Entry = CreateCStringLiteral(TypeStr, ObjCLabelType::MethodVarType);
   return getConstantGEP(VMContext, Entry, 0, 0);
 }
 
 // FIXME: Merge into a single cstring creation function.
 llvm::Constant *CGObjCCommonMac::GetPropertyName(IdentifierInfo *Ident) {
   llvm::GlobalVariable *&Entry = PropertyNames[Ident];
-
   if (!Entry)
-    Entry = CreateMetadataVar(
-        "OBJC_PROP_NAME_ATTR_",
-        llvm::ConstantDataArray::getString(VMContext, Ident->getName()),
-        "__TEXT,__cstring,cstring_literals", CharUnits::One(), true);
-
+    Entry = CreateCStringLiteral(Ident->getName(), ObjCLabelType::PropertyName);
   return getConstantGEP(VMContext, Entry, 0, 0);
 }