1 files changed, 135 insertions, 0 deletions
diff --git a/include/clang/AST/DeclContextInternals.h b/include/clang/AST/DeclContextInternals.h
new file mode 100644
index 0000000000..0aa50a1f98
--- /dev/null
+++ b/include/clang/AST/DeclContextInternals.h
@@ -0,0 +1,135 @@
+//===-- DeclContextInternals.h - DeclContext Representation -----*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file defines the data structures used in the implementation
+//  of DeclContext.
+//
+//===----------------------------------------------------------------------===//
+#ifndef LLVM_CLANG_AST_DECLCONTEXTINTERNALS_H
+#define LLVM_CLANG_AST_DECLCONTEXTINTERNALS_H
+
+#include "clang/AST/DeclBase.h"
+#include "clang/AST/DeclarationName.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/PointerUnion.h"
+#include "llvm/ADT/SmallVector.h"
+
+namespace clang {
+
+/// StoredDeclsList - This is an array of decls optimized a common case of only
+/// containing one entry.
+struct StoredDeclsList {
+  /// VectorTy - When in vector form, this is what the Data pointer points to.
+  typedef llvm::SmallVector<NamedDecl*, 4> VectorTy;
+
+  /// Data - Union of NamedDecl*/VectorTy*.
+  llvm::PointerUnion<NamedDecl*, VectorTy*> Data;
+public:
+  StoredDeclsList() {}
+  StoredDeclsList(const StoredDeclsList &RHS) : Data(RHS.Data) {
+    if (isVector())
+      Data = new VectorTy(*Data.get<VectorTy*>());
+  }
+  
+  ~StoredDeclsList() {
+    // If this is a vector-form, free the vector.
+    if (isVector())
+      delete Data.get<VectorTy*>();
+  }
+  
+  StoredDeclsList &operator=(const StoredDeclsList &RHS) {
+    if (isVector())
+      delete Data.get<VectorTy*>();
+    Data = RHS.Data;
+    if (isVector())
+      Data = new VectorTy(*Data.get<VectorTy*>());
+    return *this;
+  }
+  
+  bool isVector() const { return Data.is<VectorTy*>(); }
+  bool isInline() const { return Data.is<NamedDecl*>(); }
+  bool isNull() const { return Data.isNull(); }
+  
+  void setOnlyValue(NamedDecl *ND) {
+    assert(isInline() && "Not inline");
+    Data = ND;
+  }
+
+  /// getLookupResult - Return an array of all the decls that this list
+  /// represents.
+  DeclContext::lookup_result getLookupResult() {
+    // If we have a single inline unit, return it.
+    if (isInline()) {
+      assert(!isNull() && "Empty list isn't allowed");
+      
+      // Data is a raw pointer to a NamedDecl*, return it.
+      void *Ptr = &Data;
+      return DeclContext::lookup_result((NamedDecl**)Ptr, (NamedDecl**)Ptr+1);
+    }
+    
+    // Otherwise, we have a range result.
+    VectorTy &V = *Data.get<VectorTy*>();
+    return DeclContext::lookup_result(&V[0], &V[0]+V.size());
+  }
+  
+  /// HandleRedeclaration - If this is a redeclaration of an existing decl,
+  /// replace the old one with D and return true.  Otherwise return false.
+  bool HandleRedeclaration(NamedDecl *D) {
+    // Most decls only have one entry in their list, special case it.
+    if (isInline()) {
+      if (!D->declarationReplaces(Data.get<NamedDecl*>()))
+        return false;
+      setOnlyValue(D);
+      return true;
+    }
+    
+    // Determine if this declaration is actually a redeclaration.
+    VectorTy &Vec = *Data.get<VectorTy*>();
+    VectorTy::iterator RDI
+      = std::find_if(Vec.begin(), Vec.end(),
+                     std::bind1st(std::mem_fun(&NamedDecl::declarationReplaces),
+                                  D));
+    if (RDI == Vec.end())
+      return false;
+    *RDI = D;
+    return true;
+  }
+  
+  /// AddSubsequentDecl - This is called on the second and later decl when it is
+  /// not a redeclaration to merge it into the appropriate place in our list.
+  /// 
+  void AddSubsequentDecl(NamedDecl *D) {
+    // If this is the second decl added to the list, convert this to vector
+    // form.
+    if (isInline()) {
+      NamedDecl *OldD = Data.get<NamedDecl*>();
+      VectorTy *VT = new VectorTy();
+      VT->push_back(OldD);
+      Data = VT;
+    }
+    
+    VectorTy &Vec = *Data.get<VectorTy*>();
+    if (isa<UsingDirectiveDecl>(D) ||
+        D->getIdentifierNamespace() == Decl::IDNS_Tag)
+      Vec.push_back(D);
+    else if (Vec.back()->getIdentifierNamespace() == Decl::IDNS_Tag) {
+      NamedDecl *TagD = Vec.back();
+      Vec.back() = D;
+      Vec.push_back(TagD);
+    } else
+      Vec.push_back(D);
+  }
+};
+
+typedef llvm::DenseMap<DeclarationName, StoredDeclsList> StoredDeclsMap;
+
+
+} // end namespace clang
+
+#endif