[objc] Consolidate ObjC name mangle code to AST

[ellis]

Summary

This reduces code duplication between CGObjCMac.cpp and Mangle.cpp for generating the mangled name of an Objective-C method.

This has no intended functionality change.

[ellis]

Fix variable name

[rjmccall]

clang/include/clang/AST/Mangle.h

130

Could you switch the polarity on the method names here, so that mangleObjCMethodName just mangles the method name like ObjC would and there's a mangleObjCMethodNameAsSourceName that appends something that obeys the Itanium source-name production? You'll need to switch the existing call sites, of course.

clang/lib/AST/Mangle.cpp

323

Prefer llvm_unreachable.

[ellis]

Rename mangleObjCMethodName

[rjmccall]

Thanks, LGTM.

[ellis]

Update call sites

[ellis]

Thanks for accepting @rjmccall. Could you land this? I don't have commit access yet.

[rjmccall]

Done as 98ef7e29b0fe03da77fa6ef5c86bea9e31c178d0

[ellis]

[objc] Fix memory leak in CGObjCMac.cpp

CGObjCMac.cpp was leaking a MangleContext everytime it mangled an ObjC method. We now have an instance variable that allocates and deallocates the context.

[ellis]

Oops, I meant to create a new commit rather than amend to this one

[ellis]

https://reviews.llvm.org/D88497 will fix the leak

[vsapsai]

clang/lib/CodeGen/CGObjCMac.cpp

929

Note that the removed method is mentioned in comment docs at https://github.com/llvm/llvm-project/blob/3681be876fea9b270c7a1d2dc41679a399610e06/llvm/tools/dsymutil/SymbolMap.cpp#L50

clang/include/clang/AST/Mangle.h

void mangleGlobalBlock(const BlockDecl *BD,
                          raw_ostream &Out);
   void mangleCtorBlock(const CXXConstructorDecl *CD, CXXCtorType CT,
                        const BlockDecl *BD, raw_ostream &Out);
   void mangleDtorBlock(const CXXDestructorDecl *CD, CXXDtorType DT,
                        const BlockDecl *BD, raw_ostream &Out);
   void mangleBlock(const DeclContext *DC, const BlockDecl *BD,
                    raw_ostream &Out);
 
-  void mangleObjCMethodNameWithoutSize(const ObjCMethodDecl *MD, raw_ostream &);
+  void mangleObjCMethodNameWithoutSize(const ObjCMethodDecl *MD,
+                                       raw_ostream &OS,
+                                       bool includePrefixByte = true,
+                                       bool includeCategoryNamespace = true);
   void mangleObjCMethodName(const ObjCMethodDecl *MD, raw_ostream &);
 
   virtual void mangleStaticGuardVariable(const VarDecl *D, raw_ostream &) = 0;
 
   virtual void mangleDynamicInitializer(const VarDecl *D, raw_ostream &) = 0;
 
   virtual void mangleDynamicAtExitDestructor(const VarDecl *D,
                                              raw_ostream &) = 0;
 

clang/lib/AST/Mangle.cpp

else if (auto ND = dyn_cast<NamedDecl>(DC)) {
         // better way?
         mangleName(ND, Stream);
       }
     }
   }
   mangleFunctionBlock(*this, Buffer, BD, Out);
 }
 
-void MangleContext::mangleObjCMethodNameWithoutSize(const ObjCMethodDecl *MD,
-                                                    raw_ostream &OS) {
-  const ObjCContainerDecl *CD =
-  dyn_cast<ObjCContainerDecl>(MD->getDeclContext());
-  assert (CD && "Missing container decl in GetNameForMethod");
+void MangleContext::mangleObjCMethodNameWithoutSize(
+    const ObjCMethodDecl *MD, raw_ostream &OS, bool includePrefixByte,
+    bool includeCategoryNamespace) {
+  // \01+[ContainerName(CategoryName) SelectorName]
+  if (includePrefixByte) {
+    OS << '\01';
+  }
   OS << (MD->isInstanceMethod() ? '-' : '+') << '[';
-  if (const ObjCCategoryImplDecl *CID = dyn_cast<ObjCCategoryImplDecl>(CD)) {
+  if (auto *CID = dyn_cast<ObjCCategoryImplDecl>(MD->getDeclContext())) {
     OS << CID->getClassInterface()->getName();
+    if (includeCategoryNamespace) {
       OS << '(' << *CID << ')';
-  } else {
+    }
+  } else if (auto *CD = dyn_cast<ObjCContainerDecl>(MD->getDeclContext())) {
     OS << CD->getName();
+  } else {
+    assert(false && "Unexpected ObjC method decl context");
   }
   OS << ' ';
   MD->getSelector().print(OS);
   OS << ']';
 }
 
 void MangleContext::mangleObjCMethodName(const ObjCMethodDecl *MD,
                                          raw_ostream &Out) {
   SmallString<64> Name;
   llvm::raw_svector_ostream OS(Name);
 
-  mangleObjCMethodNameWithoutSize(MD, OS);
+  mangleObjCMethodNameWithoutSize(MD, OS, /*includePrefixByte=*/false,
+                                  /*includeCategoryNamespace=*/true);
   Out << OS.str().size() << OS.str();
 }
 
 class ASTNameGenerator::Implementation {
   std::unique_ptr<MangleContext> MC;
   llvm::DataLayout DL;
 
 public:
if (auto *FD = dyn_cast<FunctionDecl>(D)) {
       if (FD->isDependentContext())
         return true;
       if (writeFuncOrVarName(FD, FrontendBufOS))
         return true;
     } else if (auto *VD = dyn_cast<VarDecl>(D)) {
       if (writeFuncOrVarName(VD, FrontendBufOS))
         return true;
     } else if (auto *MD = dyn_cast<ObjCMethodDecl>(D)) {
-      MC->mangleObjCMethodNameWithoutSize(MD, OS);
+      MC->mangleObjCMethodNameWithoutSize(MD, OS, /*includePrefixByte=*/false,
+                                          /*includeCategoryNamespace=*/true);
       return false;
     } else if (auto *ID = dyn_cast<ObjCInterfaceDecl>(D)) {
       writeObjCClassName(ID, FrontendBufOS);
     } else {
       return true;
     }
 
     // Now apply backend mangling.

clang/lib/CodeGen/CGObjCMac.cpp

 #include "CGObjCRuntime.h"
 #include "CGRecordLayout.h"
 #include "CodeGenFunction.h"
 #include "CodeGenModule.h"
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/Attr.h"
 #include "clang/AST/Decl.h"
 #include "clang/AST/DeclObjC.h"
+#include "clang/AST/Mangle.h"
 #include "clang/AST/RecordLayout.h"
 #include "clang/AST/StmtObjC.h"
 #include "clang/Basic/CodeGenOptions.h"
 #include "clang/Basic/LangOptions.h"
 #include "clang/CodeGen/CGFunctionInfo.h"
 #include "clang/CodeGen/ConstantInitBuilder.h"
 #include "llvm/ADT/CachedHashString.h"
 #include "llvm/ADT/DenseSet.h"
protected:
   /// int * but is actually an Obj-C class pointer.
   llvm::WeakTrackingVH ConstantStringClassRef;
 
   /// The LLVM type corresponding to NSConstantString.
   llvm::StructType *NSConstantStringType = nullptr;
 
   llvm::StringMap<llvm::GlobalVariable *> NSConstantStringMap;
 
-  /// GetNameForMethod - Return a name for the given method.
-  /// \param[out] NameOut - The return value.
-  void GetNameForMethod(const ObjCMethodDecl *OMD,
-                        const ObjCContainerDecl *CD,
-                        SmallVectorImpl<char> &NameOut,
-                        bool ignoreCategoryNamespace = false);
-
   /// GetMethodVarName - Return a unique constant for the given
   /// selector's name. The return value has type char *.
   llvm::Constant *GetMethodVarName(Selector Sel);
   llvm::Constant *GetMethodVarName(IdentifierInfo *Ident);
 
   /// GetMethodVarType - Return a unique constant for the given
   /// method's type encoding string. The return value has type char *.
 

 llvm::Function *CGObjCCommonMac::GenerateMethod(const ObjCMethodDecl *OMD,
                                                 const ObjCContainerDecl *CD) {
   llvm::Function *Method;
 
   if (OMD->isDirectMethod()) {
     Method = GenerateDirectMethod(OMD, CD);
   } else {
     SmallString<256> Name;
-    GetNameForMethod(OMD, CD, Name);
+    llvm::raw_svector_ostream OS(Name);
+    const auto &MC = CGM.getContext().createMangleContext();
+    MC->mangleObjCMethodNameWithoutSize(OMD, OS, /*includePrefixByte=*/true,
+                                        /*includeCategoryNamespace=*/true);
 
     CodeGenTypes &Types = CGM.getTypes();
     llvm::FunctionType *MethodTy =
         Types.GetFunctionType(Types.arrangeObjCMethodDeclaration(OMD));
     Method =
         llvm::Function::Create(MethodTy, llvm::GlobalValue::InternalLinkage,
                                Name.str(), &CGM.getModule());
   }
if (OldFn) {
     OldFn->replaceAllUsesWith(
         llvm::ConstantExpr::getBitCast(Fn, OldFn->getType()));
     OldFn->eraseFromParent();
 
     // Replace the cached function in the map.
     I->second = Fn;
   } else {
     SmallString<256> Name;
-    GetNameForMethod(OMD, CD, Name, /*ignoreCategoryNamespace*/ true);
+    llvm::raw_svector_ostream OS(Name);
+    const auto &MC = CGM.getContext().createMangleContext();
+    MC->mangleObjCMethodNameWithoutSize(OMD, OS, /*includePrefixByte=*/true,
+                                        /*includeCategoryNamespace=*/false);
 
     Fn = llvm::Function::Create(MethodTy, llvm::GlobalValue::ExternalLinkage,
                                 Name.str(), &CGM.getModule());
     DirectMethodDefinitions.insert(std::make_pair(COMD, Fn));
   }
 
   return Fn;
 }

 llvm::Constant *
 CGObjCCommonMac::GetPropertyTypeString(const ObjCPropertyDecl *PD,
                                        const Decl *Container) {
   std::string TypeStr =
     CGM.getContext().getObjCEncodingForPropertyDecl(PD, Container);
   return GetPropertyName(&CGM.getContext().Idents.get(TypeStr));
 }
 
-void CGObjCCommonMac::GetNameForMethod(const ObjCMethodDecl *D,
-                                       const ObjCContainerDecl *CD,
-                                       SmallVectorImpl<char> &Name,
-                                       bool ignoreCategoryNamespace) {
-  llvm::raw_svector_ostream OS(Name);
-  assert (CD && "Missing container decl in GetNameForMethod");
-  OS << '\01' << (D->isInstanceMethod() ? '-' : '+')
-     << '[' << CD->getName();
-  if (!ignoreCategoryNamespace)
-    if (const ObjCCategoryImplDecl *CID =
-        dyn_cast<ObjCCategoryImplDecl>(D->getDeclContext()))
-      OS << '(' << *CID << ')';
-  OS << ' ' << D->getSelector().getAsString() << ']';
-}
-
 void CGObjCMac::FinishModule() {
   EmitModuleInfo();
 
   // Emit the dummy bodies for any protocols which were referenced but
   // never defined.
   for (auto &entry : Protocols) {
     llvm::GlobalVariable *global = entry.second;
     if (global->hasInitializer())