Vendor import of clang r114020 (from the release_28 branch):

http://llvm.org/svn/llvm-project/cfe/branches/release_28@114020

Approved by:	rpaulo (mentor)

1 files changed, 462 insertions, 0 deletions

diff --git a/include/clang/Sema/Ownership.h b/include/clang/Sema/Ownership.h
new file mode 100644
index 0000000..7739f3a
--- /dev/null
+++ b/include/clang/Sema/Ownership.h
@@ -0,0 +1,462 @@
+//===--- Ownership.h - Parser ownership helpers -----------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This file contains classes for managing ownership of Stmt and Expr nodes.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_SEMA_OWNERSHIP_H
+#define LLVM_CLANG_SEMA_OWNERSHIP_H
+
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/PointerIntPair.h"
+
+//===----------------------------------------------------------------------===//
+// OpaquePtr
+//===----------------------------------------------------------------------===//
+
+namespace clang {
+  class Attr;
+  class CXXBaseOrMemberInitializer;
+  class CXXBaseSpecifier;
+  class Decl;
+  class DeclGroupRef;
+  class Expr;
+  class NestedNameSpecifier;
+  class QualType;
+  class Sema;
+  class Stmt;
+  class TemplateName;
+  class TemplateParameterList;
+
+  /// OpaquePtr - This is a very simple POD type that wraps a pointer that the
+  /// Parser doesn't know about but that Sema or another client does.  The UID
+  /// template argument is used to make sure that "Decl" pointers are not
+  /// compatible with "Type" pointers for example.
+  template <class PtrTy>
+  class OpaquePtr {
+    void *Ptr;
+    explicit OpaquePtr(void *Ptr) : Ptr(Ptr) {}
+
+    typedef llvm::PointerLikeTypeTraits<PtrTy> Traits;
+
+  public:
+    OpaquePtr() : Ptr(0) {}
+
+    static OpaquePtr make(PtrTy P) { OpaquePtr OP; OP.set(P); return OP; }
+
+    template <typename T> T* getAs() const {
+      return get();
+    }
+
+    template <typename T> T getAsVal() const {
+      return get();
+    }
+
+    PtrTy get() const {
+      return Traits::getFromVoidPointer(Ptr);
+    }
+
+    void set(PtrTy P) {
+      Ptr = Traits::getAsVoidPointer(P);
+    }
+
+    operator bool() const { return Ptr != 0; }
+
+    void *getAsOpaquePtr() const { return Ptr; }
+    static OpaquePtr getFromOpaquePtr(void *P) { return OpaquePtr(P); }
+  };
+
+  /// UnionOpaquePtr - A version of OpaquePtr suitable for membership
+  /// in a union.
+  template <class T> struct UnionOpaquePtr {
+    void *Ptr;
+
+    static UnionOpaquePtr make(OpaquePtr<T> P) {
+      UnionOpaquePtr OP = { P.getAsOpaquePtr() };
+      return OP;
+    }
+
+    OpaquePtr<T> get() const { return OpaquePtr<T>::getFromOpaquePtr(Ptr); }
+    operator OpaquePtr<T>() const { return get(); }
+
+    UnionOpaquePtr &operator=(OpaquePtr<T> P) {
+      Ptr = P.getAsOpaquePtr();
+      return *this;
+    }
+  };
+}
+
+namespace llvm {
+  template <class T>
+  class PointerLikeTypeTraits<clang::OpaquePtr<T> > {
+  public:
+    static inline void *getAsVoidPointer(clang::OpaquePtr<T> P) {
+      // FIXME: Doesn't work? return P.getAs< void >();
+      return P.getAsOpaquePtr();
+    }
+    static inline clang::OpaquePtr<T> getFromVoidPointer(void *P) {
+      return clang::OpaquePtr<T>::getFromOpaquePtr(P);
+    }
+    enum { NumLowBitsAvailable = 0 };
+  };
+}
+
+
+
+// -------------------------- About Move Emulation -------------------------- //
+// The smart pointer classes in this file attempt to emulate move semantics
+// as they appear in C++0x with rvalue references. Since C++03 doesn't have
+// rvalue references, some tricks are needed to get similar results.
+// Move semantics in C++0x have the following properties:
+// 1) "Moving" means transferring the value of an object to another object,
+//    similar to copying, but without caring what happens to the old object.
+//    In particular, this means that the new object can steal the old object's
+//    resources instead of creating a copy.
+// 2) Since moving can modify the source object, it must either be explicitly
+//    requested by the user, or the modifications must be unnoticeable.
+// 3) As such, C++0x moving is only allowed in three contexts:
+//    * By explicitly using std::move() to request it.
+//    * From a temporary object, since that object cannot be accessed
+//      afterwards anyway, thus making the state unobservable.
+//    * On function return, since the object is not observable afterwards.
+//
+// To sum up: moving from a named object should only be possible with an
+// explicit std::move(), or on function return. Moving from a temporary should
+// be implicitly done. Moving from a const object is forbidden.
+//
+// The emulation is not perfect, and has the following shortcomings:
+// * move() is not in namespace std.
+// * move() is required on function return.
+// * There are difficulties with implicit conversions.
+// * Microsoft's compiler must be given the /Za switch to successfully compile.
+//
+// -------------------------- Implementation -------------------------------- //
+// The move emulation relies on the peculiar reference binding semantics of
+// C++03: as a rule, a non-const reference may not bind to a temporary object,
+// except for the implicit object parameter in a member function call, which
+// can refer to a temporary even when not being const.
+// The moveable object has five important functions to facilitate moving:
+// * A private, unimplemented constructor taking a non-const reference to its
+//   own class. This constructor serves a two-fold purpose.
+//   - It prevents the creation of a copy constructor that takes a const
+//     reference. Temporaries would be able to bind to the argument of such a
+//     constructor, and that would be bad.
+//   - Named objects will bind to the non-const reference, but since it's
+//     private, this will fail to compile. This prevents implicit moving from
+//     named objects.
+//   There's also a copy assignment operator for the same purpose.
+// * An implicit, non-const conversion operator to a special mover type. This
+//   type represents the rvalue reference of C++0x. Being a non-const member,
+//   its implicit this parameter can bind to temporaries.
+// * A constructor that takes an object of this mover type. This constructor
+//   performs the actual move operation. There is an equivalent assignment
+//   operator.
+// There is also a free move() function that takes a non-const reference to
+// an object and returns a temporary. Internally, this function uses explicit
+// constructor calls to move the value from the referenced object to the return
+// value.
+//
+// There are now three possible scenarios of use.
+// * Copying from a const object. Constructor overload resolution will find the
+//   non-const copy constructor, and the move constructor. The first is not
+//   viable because the const object cannot be bound to the non-const reference.
+//   The second fails because the conversion to the mover object is non-const.
+//   Moving from a const object fails as intended.
+// * Copying from a named object. Constructor overload resolution will select
+//   the non-const copy constructor, but fail as intended, because this
+//   constructor is private.
+// * Copying from a temporary. Constructor overload resolution cannot select
+//   the non-const copy constructor, because the temporary cannot be bound to
+//   the non-const reference. It thus selects the move constructor. The
+//   temporary can be bound to the implicit this parameter of the conversion
+//   operator, because of the special binding rule. Construction succeeds.
+//   Note that the Microsoft compiler, as an extension, allows binding
+//   temporaries against non-const references. The compiler thus selects the
+//   non-const copy constructor and fails, because the constructor is private.
+//   Passing /Za (disable extensions) disables this behaviour.
+// The free move() function is used to move from a named object.
+//
+// Note that when passing an object of a different type (the classes below
+// have OwningResult and OwningPtr, which should be mixable), you get a problem.
+// Argument passing and function return use copy initialization rules. The
+// effect of this is that, when the source object is not already of the target
+// type, the compiler will first seek a way to convert the source object to the
+// target type, and only then attempt to copy the resulting object. This means
+// that when passing an OwningResult where an OwningPtr is expected, the
+// compiler will first seek a conversion from OwningResult to OwningPtr, then
+// copy the OwningPtr. The resulting conversion sequence is:
+// OwningResult object -> ResultMover -> OwningResult argument to
+// OwningPtr(OwningResult) -> OwningPtr -> PtrMover -> final OwningPtr
+// This conversion sequence is too complex to be allowed. Thus the special
+// move_* functions, which help the compiler out with some explicit
+// conversions.
+
+namespace clang {
+  // Basic
+  class DiagnosticBuilder;
+
+  // Determines whether the low bit of the result pointer for the
+  // given UID is always zero. If so, ActionResult will use that bit
+  // for it's "invalid" flag.
+  template<class Ptr>
+  struct IsResultPtrLowBitFree {
+    static const bool value = false;
+  };
+
+  /// ActionResult - This structure is used while parsing/acting on
+  /// expressions, stmts, etc.  It encapsulates both the object returned by
+  /// the action, plus a sense of whether or not it is valid.
+  /// When CompressInvalid is true, the "invalid" flag will be
+  /// stored in the low bit of the Val pointer.
+  template<class PtrTy,
+           bool CompressInvalid = IsResultPtrLowBitFree<PtrTy>::value>
+  class ActionResult {
+    PtrTy Val;
+    bool Invalid;
+
+  public:
+    ActionResult(bool Invalid = false)
+      : Val(PtrTy()), Invalid(Invalid) {}
+    ActionResult(PtrTy val) : Val(val), Invalid(false) {}
+    ActionResult(const DiagnosticBuilder &) : Val(PtrTy()), Invalid(true) {}
+
+    // These two overloads prevent void* -> bool conversions.
+    ActionResult(const void *);
+    ActionResult(volatile void *);
+
+    bool isInvalid() const { return Invalid; }
+    bool isUsable() const { return !Invalid && Val; }
+
+    PtrTy get() const { return Val; }
+    PtrTy release() const { return Val; }
+    PtrTy take() const { return Val; }
+    template <typename T> T *takeAs() { return static_cast<T*>(get()); }
+
+    void set(PtrTy V) { Val = V; }
+
+    const ActionResult &operator=(PtrTy RHS) {
+      Val = RHS;
+      Invalid = false;
+      return *this;
+    }
+  };
+
+  // This ActionResult partial specialization places the "invalid"
+  // flag into the low bit of the pointer.
+  template<typename PtrTy>
+  class ActionResult<PtrTy, true> {
+    // A pointer whose low bit is 1 if this result is invalid, 0
+    // otherwise.
+    uintptr_t PtrWithInvalid;
+    typedef llvm::PointerLikeTypeTraits<PtrTy> PtrTraits;
+  public:
+    ActionResult(bool Invalid = false)
+      : PtrWithInvalid(static_cast<uintptr_t>(Invalid)) { }
+
+    ActionResult(PtrTy V) {
+      void *VP = PtrTraits::getAsVoidPointer(V);
+      PtrWithInvalid = reinterpret_cast<uintptr_t>(VP);
+      assert((PtrWithInvalid & 0x01) == 0 && "Badly aligned pointer");
+    }
+    ActionResult(const DiagnosticBuilder &) : PtrWithInvalid(0x01) { }
+
+    // These two overloads prevent void* -> bool conversions.
+    ActionResult(const void *);
+    ActionResult(volatile void *);
+
+    bool isInvalid() const { return PtrWithInvalid & 0x01; }
+    bool isUsable() const { return PtrWithInvalid > 0x01; }
+
+    PtrTy get() const {
+      void *VP = reinterpret_cast<void *>(PtrWithInvalid & ~0x01);
+      return PtrTraits::getFromVoidPointer(VP);
+    }
+    PtrTy take() const { return get(); }
+    PtrTy release() const { return get(); }
+    template <typename T> T *takeAs() { return static_cast<T*>(get()); }
+
+    void set(PtrTy V) {
+      void *VP = PtrTraits::getAsVoidPointer(V);
+      PtrWithInvalid = reinterpret_cast<uintptr_t>(VP);
+      assert((PtrWithInvalid & 0x01) == 0 && "Badly aligned pointer");
+    }
+
+    const ActionResult &operator=(PtrTy RHS) {
+      void *VP = PtrTraits::getAsVoidPointer(RHS);
+      PtrWithInvalid = reinterpret_cast<uintptr_t>(VP);
+      assert((PtrWithInvalid & 0x01) == 0 && "Badly aligned pointer");
+      return *this;
+    }
+  };
+
+  /// ASTMultiPtr - A moveable smart pointer to multiple AST nodes. Only owns
+  /// the individual pointers, not the array holding them.
+  template <typename PtrTy> class ASTMultiPtr;
+
+  template <class PtrTy>
+  class ASTMultiPtr {
+    PtrTy *Nodes;
+    unsigned Count;
+
+  public:
+    // Normal copying implicitly defined
+    ASTMultiPtr() : Nodes(0), Count(0) {}
+    explicit ASTMultiPtr(Sema &) : Nodes(0), Count(0) {}
+    ASTMultiPtr(Sema &, PtrTy *nodes, unsigned count)
+      : Nodes(nodes), Count(count) {}
+    // Fake mover in Parse/AstGuard.h needs this:
+    ASTMultiPtr(PtrTy *nodes, unsigned count) : Nodes(nodes), Count(count) {}
+
+    /// Access to the raw pointers.
+    PtrTy *get() const { return Nodes; }
+
+    /// Access to the count.
+    unsigned size() const { return Count; }
+
+    PtrTy *release() {
+      return Nodes;
+    }
+  };
+
+  class ParsedTemplateArgument;
+    
+  class ASTTemplateArgsPtr {
+    ParsedTemplateArgument *Args;
+    mutable unsigned Count;
+
+  public:
+    ASTTemplateArgsPtr(Sema &actions, ParsedTemplateArgument *args,
+                       unsigned count) :
+      Args(args), Count(count) { }
+
+    // FIXME: Lame, not-fully-type-safe emulation of 'move semantics'.
+    ASTTemplateArgsPtr(ASTTemplateArgsPtr &Other) :
+      Args(Other.Args), Count(Other.Count) {
+    }
+
+    // FIXME: Lame, not-fully-type-safe emulation of 'move semantics'.
+    ASTTemplateArgsPtr& operator=(ASTTemplateArgsPtr &Other)  {
+      Args = Other.Args;
+      Count = Other.Count;
+      return *this;
+    }
+
+    ParsedTemplateArgument *getArgs() const { return Args; }
+    unsigned size() const { return Count; }
+
+    void reset(ParsedTemplateArgument *args, unsigned count) {
+      Args = args;
+      Count = count;
+    }
+
+    const ParsedTemplateArgument &operator[](unsigned Arg) const;
+
+    ParsedTemplateArgument *release() const {
+      return Args;
+    }
+  };
+
+  /// \brief A small vector that owns a set of AST nodes.
+  template <class PtrTy, unsigned N = 8>
+  class ASTOwningVector : public llvm::SmallVector<PtrTy, N> {
+    ASTOwningVector(ASTOwningVector &); // do not implement
+    ASTOwningVector &operator=(ASTOwningVector &); // do not implement
+
+  public:
+    explicit ASTOwningVector(Sema &Actions)
+    { }
+
+    PtrTy *take() {
+      return &this->front();
+    }
+
+    template<typename T> T **takeAs() { return reinterpret_cast<T**>(take()); }
+  };
+
+  /// A SmallVector of statements, with stack size 32 (as that is the only one
+  /// used.)
+  typedef ASTOwningVector<Stmt*, 32> StmtVector;
+  /// A SmallVector of expressions, with stack size 12 (the maximum used.)
+  typedef ASTOwningVector<Expr*, 12> ExprVector;
+
+  template <class T, unsigned N> inline
+  ASTMultiPtr<T> move_arg(ASTOwningVector<T, N> &vec) {
+    return ASTMultiPtr<T>(vec.take(), vec.size());
+  }
+
+  // These versions are hopefully no-ops.
+  template <class T, bool C>
+  inline ActionResult<T,C> move(ActionResult<T,C> &ptr) {
+    return ptr;
+  }
+
+  template <class T> inline
+  ASTMultiPtr<T>& move(ASTMultiPtr<T> &ptr) {
+    return ptr;
+  }
+
+  // We can re-use the low bit of expression, statement, base, and
+  // member-initializer pointers for the "invalid" flag of
+  // ActionResult.
+  template<> struct IsResultPtrLowBitFree<Expr*> {
+    static const bool value = true;
+  };
+  template<> struct IsResultPtrLowBitFree<Stmt*> {
+    static const bool value = true;
+  };
+  template<> struct IsResultPtrLowBitFree<CXXBaseSpecifier*> {
+    static const bool value = true;
+  };
+  template<> struct IsResultPtrLowBitFree<CXXBaseOrMemberInitializer*> {
+    static const bool value = true;
+  };
+
+  /// An opaque type for threading parsed type information through the
+  /// parser.
+  typedef OpaquePtr<QualType> ParsedType;
+  typedef UnionOpaquePtr<QualType> UnionParsedType;
+
+  typedef ActionResult<Expr*> ExprResult;
+  typedef ActionResult<Stmt*> StmtResult;
+  typedef ActionResult<ParsedType> TypeResult;
+  typedef ActionResult<CXXBaseSpecifier*> BaseResult;
+  typedef ActionResult<CXXBaseOrMemberInitializer*> MemInitResult;
+
+  typedef ActionResult<Decl*> DeclResult;
+  typedef OpaquePtr<TemplateName> ParsedTemplateTy;
+
+  inline Expr *move(Expr *E) { return E; }
+  inline Stmt *move(Stmt *S) { return S; }
+
+  typedef ASTMultiPtr<Expr*> MultiExprArg;
+  typedef ASTMultiPtr<Stmt*> MultiStmtArg;
+  typedef ASTMultiPtr<TemplateParameterList*> MultiTemplateParamsArg;
+
+  inline ExprResult ExprError() { return ExprResult(true); }
+  inline StmtResult StmtError() { return StmtResult(true); }
+
+  inline ExprResult ExprError(const DiagnosticBuilder&) { return ExprError(); }
+  inline StmtResult StmtError(const DiagnosticBuilder&) { return StmtError(); }
+
+  inline ExprResult ExprEmpty() { return ExprResult(false); }
+  inline StmtResult StmtEmpty() { return StmtResult(false); }
+
+  inline Expr *AssertSuccess(ExprResult R) {
+    assert(!R.isInvalid() && "operation was asserted to never fail!");
+    return R.get();
+  }
+
+  inline Stmt *AssertSuccess(StmtResult R) {
+    assert(!R.isInvalid() && "operation was asserted to never fail!");
+    return R.get();
+  }
+}
+
+#endif