From a5e23f6b789374b48b9831199e3562432afcf7f8 Mon Sep 17 00:00:00 2001
From: Ted Kremenek <kremenek@apple.com>
Date: Thu, 25 Sep 2008 17:13:40 +0000
Subject: [PATCH] Added prototype implementation of the DeclGroup,
 DeclGroupRef, and DeclGroupOwningRef classes. Documentation and testing are
 pending.

llvm-svn: 56611
---
 clang/include/clang/AST/DeclGroup.h | 96 +++++++++++++++++++++++++++++
 clang/lib/AST/DeclGroup.cpp         | 59 ++++++++++++++++++
 2 files changed, 155 insertions(+)
 create mode 100644 clang/include/clang/AST/DeclGroup.h
 create mode 100644 clang/lib/AST/DeclGroup.cpp

diff --git a/clang/include/clang/AST/DeclGroup.h b/clang/include/clang/AST/DeclGroup.h
new file mode 100644
index 000000000000..75095d6c0088
--- /dev/null
+++ b/clang/include/clang/AST/DeclGroup.h
@@ -0,0 +1,96 @@
+//===--- DeclGroup.h - Classes for representing groups of Decls -*- 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 DeclGroup, DeclGroupRef, and OwningDeclGroup classes.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_AST_DECLGROUP_H
+#define LLVM_CLANG_AST_DECLGROUP_H
+
+#include "llvm/Support/DataTypes.h"
+#include <cassert>
+
+namespace clang {
+  
+class ASTContext;
+class Decl;
+class DeclGroup;
+class DeclGroupIterator;
+
+class DeclGroup {
+  // FIXME: Include a TypeSpecifier object.
+  unsigned NumDecls;
+  
+private:
+  DeclGroup(unsigned numdecls, Decl** decls);
+
+public:
+  static DeclGroup* Create(ASTContext& C, unsigned numdecls, Decl** decls);
+  void Destroy(ASTContext& C);
+
+  unsigned size() const { return NumDecls; }
+  Decl*& operator[](unsigned i) { 
+    assert (i < NumDecls && "Out-of-bounds access.");
+    return *((Decl**) (this+1));
+  }
+};
+  
+class DeclGroupRef {
+protected:
+  enum Kind { DeclKind=0x0, DeclGroupKind=0x1, Mask=0x1 };
+  uintptr_t ThePtr;
+
+  Kind getKind() const { return (Kind) (ThePtr & Mask); }  
+  
+public:    
+  DeclGroupRef() : ThePtr(0) {}
+  
+  explicit DeclGroupRef(Decl* D)
+    : ThePtr(reinterpret_cast<uintptr_t>(D)) {}
+  
+  explicit DeclGroupRef(DeclGroup* D)
+    : ThePtr(reinterpret_cast<uintptr_t>(D) | DeclGroupKind) {}
+  
+  typedef Decl** iterator;
+
+  iterator begin() {
+    if (getKind() == DeclKind)
+      return ThePtr ? (Decl**) &ThePtr : 0;
+
+    DeclGroup* G = reinterpret_cast<DeclGroup*>(ThePtr & ~Mask);
+    return &(*G)[0];
+  }
+
+  iterator end() {
+    if (getKind() == DeclKind)
+      return ThePtr ? ((Decl**) &ThePtr) + 1 : 0;
+    
+    DeclGroup* G = reinterpret_cast<DeclGroup*>(ThePtr & ~Mask);
+    return &(*G)[0] + G->size();
+  }  
+};
+  
+class DeclGroupOwningRef : public DeclGroupRef {
+public:
+  ~DeclGroupOwningRef();  
+  void Destroy(ASTContext& C);
+  
+  explicit DeclGroupOwningRef(DeclGroupOwningRef& R)
+    : DeclGroupRef(R) { R.ThePtr = 0; }
+
+  DeclGroupOwningRef& operator=(DeclGroupOwningRef& R) {
+    ThePtr = R.ThePtr;
+    R.ThePtr = 0;
+    return *this;
+  }
+};
+
+} // end clang namespace
+#endif
diff --git a/clang/lib/AST/DeclGroup.cpp b/clang/lib/AST/DeclGroup.cpp
new file mode 100644
index 000000000000..5987d5a7012a
--- /dev/null
+++ b/clang/lib/AST/DeclGroup.cpp
@@ -0,0 +1,59 @@
+//===--- DeclGroup.cpp - Classes for representing groups of Decls -*- 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 DeclGroup, DeclGroupRef, and OwningDeclGroup classes.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/AST/DeclGroup.h"
+#include "clang/AST/Decl.h"
+#include "clang/AST/ASTContext.h"
+#include "llvm/Support/Allocator.h"
+
+using namespace clang;
+
+DeclGroup* DeclGroup::Create(ASTContext& C, unsigned numdecls, Decl** decls) {
+  unsigned size = sizeof(DeclGroup) + sizeof(Decl*) * numdecls;
+  unsigned alignment = llvm::AlignOf<DeclGroup>::Alignment;  
+  void* mem = C.getAllocator().Allocate(size, alignment);                                                   
+  new (mem) DeclGroup(numdecls, decls);
+  return static_cast<DeclGroup*>(mem);
+}
+
+DeclGroup::DeclGroup(unsigned numdecls, Decl** decls) {
+  assert (numdecls > 0);
+  assert (decls);
+  memcpy(this+1, decls, numdecls * sizeof(*decls));
+}
+
+void DeclGroup::Destroy(ASTContext& C) {
+  Decl** Decls = (Decl**) this + 1;
+  
+  for (unsigned i = 0; i < NumDecls; ++i)
+    Decls[i]->Destroy(C);
+  
+  this->~DeclGroup();
+  C.getAllocator().Deallocate((void*) this);
+}
+
+DeclGroupOwningRef::~DeclGroupOwningRef() {
+  assert (ThePtr == 0 && "Destroy method not called.");
+}
+
+void DeclGroupOwningRef::Destroy(ASTContext& C) {
+  if (!ThePtr)
+    return;
+  
+  if (getKind() == DeclKind)
+    reinterpret_cast<Decl*>(ThePtr)->Destroy(C);
+  else
+    reinterpret_cast<DeclGroup*>(ThePtr & ~Mask)->Destroy(C);
+  
+  ThePtr = 0;
+}