X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FSupport%2FErrorOr.h;h=ca6ede73e8df1315d6eb7da25569123127e208ff;hb=b9f514b1bf24a7b370f03868189ed6946ead2ed7;hp=625574b88b277dff0d4fd24229a838b1e607aa2d;hpb=1bab2d53996ca082150f34d8dafc1968fb5ecba9;p=oota-llvm.git

diff --git a/include/llvm/Support/ErrorOr.h b/include/llvm/Support/ErrorOr.h
index 625574b88b2..ca6ede73e8d 100644
--- a/include/llvm/Support/ErrorOr.h
+++ b/include/llvm/Support/ErrorOr.h
@@ -1,4 +1,4 @@
-//===- llvm/Support/ErrorOr.h - Error Smart Pointer -----------------------===//
+//===- llvm/Support/ErrorOr.h - Error Smart Pointer -------------*- C++ -*-===//
 //
 //                             The LLVM Linker
 //
@@ -13,13 +13,13 @@
 ///
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_SUPPORT_ERROR_OR_H
-#define LLVM_SUPPORT_ERROR_OR_H
+#ifndef LLVM_SUPPORT_ERROROR_H
+#define LLVM_SUPPORT_ERROROR_H
 
 #include "llvm/ADT/PointerIntPair.h"
 #include "llvm/Support/AlignOf.h"
-#include "llvm/Support/system_error.h"
 #include <cassert>
+#include <system_error>
 #include <type_traits>
 
 namespace llvm {
@@ -68,9 +68,9 @@ public:
 /// \endcode
 ///
 ///
-/// An implicit conversion to bool provides a way to check if there was an
-/// error. The unary * and -> operators provide pointer like access to the
-/// value. Accessing the value when there is an error has undefined behavior.
+/// Implicit conversion to bool returns true if there is a usable value. The
+/// unary * and -> operators provide pointer like access to the value. Accessing
+/// the value when there is an error has undefined behavior.
 ///
 /// When T is a reference type the behaivor is slightly different. The reference
 /// is held in a std::reference_wrapper<std::remove_reference<T>::type>, and
@@ -91,18 +91,20 @@ private:
   typedef typename std::remove_reference<T>::type &reference;
   typedef const typename std::remove_reference<T>::type &const_reference;
   typedef typename std::remove_reference<T>::type *pointer;
+  typedef const typename std::remove_reference<T>::type *const_pointer;
 
 public:
   template <class E>
-  ErrorOr(E ErrorCode, typename std::enable_if<is_error_code_enum<E>::value ||
-                                               is_error_condition_enum<E>::value,
-                                               void *>::type = 0)
+  ErrorOr(E ErrorCode,
+          typename std::enable_if<std::is_error_code_enum<E>::value ||
+                                      std::is_error_condition_enum<E>::value,
+                                  void *>::type = 0)
       : HasError(true) {
-    new (getErrorStorage()) error_code(make_error_code(ErrorCode));
+    new (getErrorStorage()) std::error_code(make_error_code(ErrorCode));
   }
 
-  ErrorOr(llvm::error_code EC) : HasError(true) {
-    new (getErrorStorage()) error_code(EC);
+  ErrorOr(std::error_code EC) : HasError(true) {
+    new (getErrorStorage()) std::error_code(EC);
   }
 
   ErrorOr(T Val) : HasError(false) {
@@ -114,19 +116,19 @@ public:
   }
 
   template <class OtherT>
-  ErrorOr(const ErrorOr<OtherT> &Other) {
+  ErrorOr(
+      const ErrorOr<OtherT> &Other,
+      typename std::enable_if<std::is_convertible<OtherT, T>::value>::type * =
+          nullptr) {
     copyConstruct(Other);
   }
 
-  ErrorOr &operator =(const ErrorOr &Other) {
-    copyAssign(Other);
-    return *this;
-  }
-
   template <class OtherT>
-  ErrorOr &operator =(const ErrorOr<OtherT> &Other) {
-    copyAssign(Other);
-    return *this;
+  explicit ErrorOr(
+      const ErrorOr<OtherT> &Other,
+      typename std::enable_if<
+          !std::is_convertible<OtherT, const T &>::value>::type * = nullptr) {
+    copyConstruct(Other);
   }
 
   ErrorOr(ErrorOr &&Other) {
@@ -134,17 +136,29 @@ public:
   }
 
   template <class OtherT>
-  ErrorOr(ErrorOr<OtherT> &&Other) {
+  ErrorOr(
+      ErrorOr<OtherT> &&Other,
+      typename std::enable_if<std::is_convertible<OtherT, T>::value>::type * =
+          nullptr) {
     moveConstruct(std::move(Other));
   }
 
-  ErrorOr &operator =(ErrorOr &&Other) {
-    moveAssign(std::move(Other));
+  // This might eventually need SFINAE but it's more complex than is_convertible
+  // & I'm too lazy to write it right now.
+  template <class OtherT>
+  explicit ErrorOr(
+      ErrorOr<OtherT> &&Other,
+      typename std::enable_if<!std::is_convertible<OtherT, T>::value>::type * =
+          nullptr) {
+    moveConstruct(std::move(Other));
+  }
+
+  ErrorOr &operator=(const ErrorOr &Other) {
+    copyAssign(Other);
     return *this;
   }
 
-  template <class OtherT>
-  ErrorOr &operator =(ErrorOr<OtherT> &&Other) {
+  ErrorOr &operator=(ErrorOr &&Other) {
     moveAssign(std::move(Other));
     return *this;
   }
@@ -155,25 +169,29 @@ public:
   }
 
   /// \brief Return false if there is an error.
-  LLVM_EXPLICIT operator bool() const {
+  explicit operator bool() const {
     return !HasError;
   }
 
   reference get() { return *getStorage(); }
-  const_reference get() const { return const_cast<ErrorOr<T> >(this)->get(); }
+  const_reference get() const { return const_cast<ErrorOr<T> *>(this)->get(); }
 
-  error_code getError() const {
-    return HasError ? *getErrorStorage() : error_code();
+  std::error_code getError() const {
+    return HasError ? *getErrorStorage() : std::error_code();
   }
 
   pointer operator ->() {
     return toPointer(getStorage());
   }
 
+  const_pointer operator->() const { return toPointer(getStorage()); }
+
   reference operator *() {
     return *getStorage();
   }
 
+  const_reference operator*() const { return *getStorage(); }
+
 private:
   template <class OtherT>
   void copyConstruct(const ErrorOr<OtherT> &Other) {
@@ -184,7 +202,7 @@ private:
     } else {
       // Get other's error.
       HasError = true;
-      new (getErrorStorage()) error_code(Other.getError());
+      new (getErrorStorage()) std::error_code(Other.getError());
     }
   }
 
@@ -216,7 +234,7 @@ private:
     } else {
       // Get other's error.
       HasError = true;
-      new (getErrorStorage()) error_code(Other.getError());
+      new (getErrorStorage()) std::error_code(Other.getError());
     }
   }
 
@@ -233,10 +251,14 @@ private:
     return Val;
   }
 
+  const_pointer toPointer(const_pointer Val) const { return Val; }
+
   pointer toPointer(wrap *Val) {
     return &Val->get();
   }
 
+  const_pointer toPointer(const wrap *Val) const { return &Val->get(); }
+
   storage_type *getStorage() {
     assert(!HasError && "Cannot get value when an error exists!");
     return reinterpret_cast<storage_type*>(TStorage.buffer);
@@ -247,28 +269,29 @@ private:
     return reinterpret_cast<const storage_type*>(TStorage.buffer);
   }
 
-  error_code *getErrorStorage() {
+  std::error_code *getErrorStorage() {
     assert(HasError && "Cannot get error when a value exists!");
-    return reinterpret_cast<error_code*>(ErrorStorage.buffer);
+    return reinterpret_cast<std::error_code *>(ErrorStorage.buffer);
   }
 
-  const error_code *getErrorStorage() const {
+  const std::error_code *getErrorStorage() const {
     return const_cast<ErrorOr<T> *>(this)->getErrorStorage();
   }
 
 
   union {
     AlignedCharArrayUnion<storage_type> TStorage;
-    AlignedCharArrayUnion<error_code> ErrorStorage;
+    AlignedCharArrayUnion<std::error_code> ErrorStorage;
   };
   bool HasError : 1;
 };
 
-template<class T, class E>
-typename std::enable_if<is_error_code_enum<E>::value ||
-                        is_error_condition_enum<E>::value, bool>::type
-operator ==(ErrorOr<T> &Err, E Code) {
-  return error_code(Err) == Code;
+template <class T, class E>
+typename std::enable_if<std::is_error_code_enum<E>::value ||
+                            std::is_error_condition_enum<E>::value,
+                        bool>::type
+operator==(const ErrorOr<T> &Err, E Code) {
+  return Err.getError() == Code;
 }
 } // end namespace llvm