Remove unneeded struct; NFC

[sanjoy]

Summary

Unless I'm missing something, the DeferredGlobal struct's GV field is
unused, removing which makes the struct itself trivial.

[chandlerc]

LGTM.

This seems trivially correct. Feel free to submit. If there is a use case, we can always add this back equally trivially when the code to use it is added...

cfe/trunk/lib/CodeGen/CodeGenModule.h

private:
   /// This contains all the decls which have definitions but/ which are deferred
   /// for emission and therefore should only be output if they are actually
   /// used. If a decl is in this, then it is known to have not been referenced
   /// yet.
   std::map<StringRef, GlobalDecl> DeferredDecls;
 
   /// This is a list of deferred decls which we have seen that *are* actually
   /// referenced. These get code generated when the module is done.
-  struct DeferredGlobal {
-    DeferredGlobal(llvm::GlobalValue *GV, GlobalDecl GD) : GV(GV), GD(GD) {}
-    llvm::TrackingVH<llvm::GlobalValue> GV;
-    GlobalDecl GD;
-  };
-  std::vector<DeferredGlobal> DeferredDeclsToEmit;
-  void addDeferredDeclToEmit(llvm::GlobalValue *GV, GlobalDecl GD) {
-    DeferredDeclsToEmit.emplace_back(GV, GD);
+  std::vector<GlobalDecl> DeferredDeclsToEmit;
+  void addDeferredDeclToEmit(GlobalDecl GD) {
+    DeferredDeclsToEmit.emplace_back(GD);
   }
 
   /// List of alias we have emitted. Used to make sure that what they point to
   /// is defined once we get to the end of the of the translation unit.
   std::vector<GlobalDecl> Aliases;
 
   typedef llvm::StringMap<llvm::TrackingVH<llvm::Constant> > ReplacementsTy;
   ReplacementsTy Replacements;

cfe/trunk/lib/CodeGen/CodeGenModule.cpp

void CodeGenModule::EmitDeferred() {
   }
 
   // Stop if we're out of both deferred vtables and deferred declarations.
   if (DeferredDeclsToEmit.empty())
     return;
 
   // Grab the list of decls to emit. If EmitGlobalDefinition schedules more
   // work, it will not interfere with this.
-  std::vector<DeferredGlobal> CurDeclsToEmit;
+  std::vector<GlobalDecl> CurDeclsToEmit;
   CurDeclsToEmit.swap(DeferredDeclsToEmit);
 
-  for (DeferredGlobal &G : CurDeclsToEmit) {
-    GlobalDecl D = G.GD;
-    G.GV = nullptr;
-
+  for (GlobalDecl &D : CurDeclsToEmit) {
     // We should call GetAddrOfGlobal with IsForDefinition set to true in order
     // to get GlobalValue with exactly the type we need, not something that
     // might had been created for another decl with the same mangled name but
     // different type.
     llvm::GlobalValue *GV = dyn_cast<llvm::GlobalValue>(
         GetAddrOfGlobal(D, ForDefinition));
 
     // In case of different address spaces, we may still get a cast, even with
void CodeGenModule::EmitGlobal(GlobalDecl GD) {
   // initializer, remember the order in which it appeared in the file.
   if (getLangOpts().CPlusPlus && isa<VarDecl>(Global) &&
       cast<VarDecl>(Global)->hasInit()) {
     DelayedCXXInitPosition[Global] = CXXGlobalInits.size();
     CXXGlobalInits.push_back(nullptr);
   }
 
   StringRef MangledName = getMangledName(GD);
-  if (llvm::GlobalValue *GV = GetGlobalValue(MangledName)) {
+  if (GetGlobalValue(MangledName) != nullptr) {
     // The value has already been used and should therefore be emitted.
-    addDeferredDeclToEmit(GV, GD);
+    addDeferredDeclToEmit(GD);
   } else if (MustBeEmitted(Global)) {
     // The value must be emitted, but cannot be emitted eagerly.
     assert(!MayBeEmittedEagerly(Global));
-    addDeferredDeclToEmit(/*GV=*/nullptr, GD);
+    addDeferredDeclToEmit(GD);
   } else {
     // Otherwise, remember that we saw a deferred decl with this name.  The
     // first use of the mangled name will cause it to move into
     // DeferredDeclsToEmit.
     DeferredDecls[MangledName] = GD;
   }
 }
 
llvm::Constant *CodeGenModule::GetOrCreateLLVMFunction(
 
   if (!DontDefer) {
     // All MSVC dtors other than the base dtor are linkonce_odr and delegate to
     // each other bottoming out with the base dtor.  Therefore we emit non-base
     // dtors on usage, even if there is no dtor definition in the TU.
     if (D && isa<CXXDestructorDecl>(D) &&
         getCXXABI().useThunkForDtorVariant(cast<CXXDestructorDecl>(D),
                                            GD.getDtorType()))
-      addDeferredDeclToEmit(F, GD);
+      addDeferredDeclToEmit(GD);
 
     // This is the first use or definition of a mangled name.  If there is a
     // deferred decl with this name, remember that we need to emit it at the end
     // of the file.
     auto DDI = DeferredDecls.find(MangledName);
     if (DDI != DeferredDecls.end()) {
       // Move the potentially referenced deferred decl to the
       // DeferredDeclsToEmit list, and remove it from DeferredDecls (since we
       // don't need it anymore).
-      addDeferredDeclToEmit(F, DDI->second);
+      addDeferredDeclToEmit(DDI->second);
       DeferredDecls.erase(DDI);
 
       // Otherwise, there are cases we have to worry about where we're
       // using a declaration for which we must emit a definition but where
       // we might not find a top-level definition:
       //   - member functions defined inline in their classes
       //   - friend functions defined inline in some class
       //   - special member functions with implicit definitions
       // If we ever change our AST traversal to walk into class methods,
       // this will be unnecessary.
       //
       // We also don't emit a definition for a function if it's going to be an
       // entry in a vtable, unless it's already marked as used.
     } else if (getLangOpts().CPlusPlus && D) {
       // Look for a declaration that's lexically in a record.
       for (const auto *FD = cast<FunctionDecl>(D)->getMostRecentDecl(); FD;
            FD = FD->getPreviousDecl()) {
         if (isa<CXXRecordDecl>(FD->getLexicalDeclContext())) {
           if (FD->doesThisDeclarationHaveABody()) {
-            addDeferredDeclToEmit(F, GD.getWithDecl(FD));
+            addDeferredDeclToEmit(GD.getWithDecl(FD));
             break;
           }
         }
       }
     }
   }
 
   // Make sure the result is of the requested type.
CodeGenModule::GetOrCreateLLVMGlobal(StringRef MangledName,
 
   // This is the first use or definition of a mangled name.  If there is a
   // deferred decl with this name, remember that we need to emit it at the end
   // of the file.
   auto DDI = DeferredDecls.find(MangledName);
   if (DDI != DeferredDecls.end()) {
     // Move the potentially referenced deferred decl to the DeferredDeclsToEmit
     // list, and remove it from DeferredDecls (since we don't need it anymore).
-    addDeferredDeclToEmit(GV, DDI->second);
+    addDeferredDeclToEmit(DDI->second);
     DeferredDecls.erase(DDI);
   }
 
   // Handle things which are present even on external declarations.
   if (D) {
     // FIXME: This code is overly simple and should be merged with other global
     // handling.
     GV->setConstant(isTypeConstant(D->getType(), false));