X-Git-Url: http://plrg.eecs.uci.edu/git/?p=oota-llvm.git;a=blobdiff_plain;f=include%2Fllvm%2FSupport%2FCasting.h;h=beed31a4084f60f2383586bf05382ba2fed1923a;hp=e0d50fe5d552c327d19a505ab69d160d9868b91a;hb=ec0f0bc6afa8d2c1f427ec55264fc78738b83ef6;hpb=5a6d63ae29512d654c8c697f42f32f97b9dc010b

diff --git a/include/llvm/Support/Casting.h b/include/llvm/Support/Casting.h
index e0d50fe5d55..beed31a4084 100644
--- a/include/llvm/Support/Casting.h
+++ b/include/llvm/Support/Casting.h
@@ -1,21 +1,30 @@
-//===-- Support/Casting.h - Allow flexible, checked, casts -------*- C++ -*--=//
+//===-- llvm/Support/Casting.h - Allow flexible, checked, casts -*- 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 isa<X>(), cast<X>(), dyn_cast<X>(), cast_or_null<X>(),
 // and dyn_cast_or_null<X>() templates.
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef SUPPORT_CASTING_H
-#define SUPPORT_CASTING_H
+#ifndef LLVM_SUPPORT_CASTING_H
+#define LLVM_SUPPORT_CASTING_H
+
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/type_traits.h"
+#include <cassert>
 
-#include <assert.h>
+namespace llvm {
 
 //===----------------------------------------------------------------------===//
 //                          isa<x> Support Templates
 //===----------------------------------------------------------------------===//
 
-template<typename FromCl> struct isa_impl_cl;
-
 // Define a template that can be specialized by smart pointers to reflect the
 // fact that they are automatically dereferenced, and are not involved with the
 // template selection process...  the default implementation is a noop.
@@ -28,83 +37,101 @@ template<typename From> struct simplify_type {
 };
 
 template<typename From> struct simplify_type<const From> {
-  typedef const From SimpleType;
-  static SimpleType &getSimplifiedValue(const From &Val) {
-    return simplify_type<From>::getSimplifiedValue((From&)Val);
+  typedef typename simplify_type<From>::SimpleType NonConstSimpleType;
+  typedef typename add_const_past_pointer<NonConstSimpleType>::type
+    SimpleType;
+  typedef typename add_lvalue_reference_if_not_pointer<SimpleType>::type
+    RetType;
+  static RetType getSimplifiedValue(const From& Val) {
+    return simplify_type<From>::getSimplifiedValue(const_cast<From&>(Val));
   }
 };
 
+// The core of the implementation of isa<X> is here; To and From should be
+// the names of classes.  This template can be specialized to customize the
+// implementation of isa<> without rewriting it from scratch.
+template <typename To, typename From, typename Enabler = void>
+struct isa_impl {
+  static inline bool doit(const From &Val) {
+    return To::classof(&Val);
+  }
+};
 
-// isa<X> - Return true if the parameter to the template is an instance of the
-// template type argument.  Used like this:
-//
-//  if (isa<Type*>(myVal)) { ... }
-//
+/// \brief Always allow upcasts, and perform no dynamic check for them.
 template <typename To, typename From>
-inline bool isa_impl(const From &Val) { 
-  return To::classof(&Val);
-}
+struct isa_impl<
+    To, From, typename std::enable_if<std::is_base_of<To, From>::value>::type> {
+  static inline bool doit(const From &) { return true; }
+};
 
-template<typename To, typename From, typename SimpleType>
-struct isa_impl_wrap {
-  // When From != SimplifiedType, we can simplify the type some more by using
-  // the simplify_type template.
-  static bool doit(const From &Val) {
-    return isa_impl_cl<const SimpleType>::template 
-                    isa<To>(simplify_type<const From>::getSimplifiedValue(Val));
+template <typename To, typename From> struct isa_impl_cl {
+  static inline bool doit(const From &Val) {
+    return isa_impl<To, From>::doit(Val);
   }
 };
 
-template<typename To, typename FromTy>
-struct isa_impl_wrap<To, const FromTy, const FromTy> {
-  // When From == SimpleType, we are as simple as we are going to get.
-  static bool doit(const FromTy &Val) {
-    return isa_impl<To,FromTy>(Val);
+template <typename To, typename From> struct isa_impl_cl<To, const From> {
+  static inline bool doit(const From &Val) {
+    return isa_impl<To, From>::doit(Val);
   }
 };
 
-// isa_impl_cl - Use class partial specialization to transform types to a single
-// cannonical form for isa_impl.
-//
-template<typename FromCl>
-struct isa_impl_cl {
-  template<class ToCl>
-  static bool isa(const FromCl &Val) {
-    return isa_impl_wrap<ToCl,const FromCl,
-                   typename simplify_type<const FromCl>::SimpleType>::doit(Val);
+template <typename To, typename From> struct isa_impl_cl<To, From*> {
+  static inline bool doit(const From *Val) {
+    assert(Val && "isa<> used on a null pointer");
+    return isa_impl<To, From>::doit(*Val);
+  }
+};
+
+template <typename To, typename From> struct isa_impl_cl<To, From*const> {
+  static inline bool doit(const From *Val) {
+    assert(Val && "isa<> used on a null pointer");
+    return isa_impl<To, From>::doit(*Val);
   }
 };
 
-// Specialization used to strip const qualifiers off of the FromCl type...
-template<typename FromCl>
-struct isa_impl_cl<const FromCl> {
-  template<class ToCl>
-  static bool isa(const FromCl &Val) {
-    return isa_impl_cl<FromCl>::template isa<ToCl>(Val);
+template <typename To, typename From> struct isa_impl_cl<To, const From*> {
+  static inline bool doit(const From *Val) {
+    assert(Val && "isa<> used on a null pointer");
+    return isa_impl<To, From>::doit(*Val);
   }
 };
 
-// Define pointer traits in terms of base traits...
-template<class FromCl>
-struct isa_impl_cl<FromCl*> {
-  template<class ToCl>
-  static bool isa(FromCl *Val) {
-    return isa_impl_cl<FromCl>::template isa<ToCl>(*Val);
+template <typename To, typename From> struct isa_impl_cl<To, const From*const> {
+  static inline bool doit(const From *Val) {
+    assert(Val && "isa<> used on a null pointer");
+    return isa_impl<To, From>::doit(*Val);
   }
 };
 
-// Define reference traits in terms of base traits...
-template<class FromCl>
-struct isa_impl_cl<FromCl&> {
-  template<class ToCl>
-  static bool isa(FromCl &Val) {
-    return isa_impl_cl<FromCl>::template isa<ToCl>(&Val);
+template<typename To, typename From, typename SimpleFrom>
+struct isa_impl_wrap {
+  // When From != SimplifiedType, we can simplify the type some more by using
+  // the simplify_type template.
+  static bool doit(const From &Val) {
+    return isa_impl_wrap<To, SimpleFrom,
+      typename simplify_type<SimpleFrom>::SimpleType>::doit(
+                          simplify_type<const From>::getSimplifiedValue(Val));
   }
 };
 
+template<typename To, typename FromTy>
+struct isa_impl_wrap<To, FromTy, FromTy> {
+  // When From == SimpleType, we are as simple as we are going to get.
+  static bool doit(const FromTy &Val) {
+    return isa_impl_cl<To,FromTy>::doit(Val);
+  }
+};
+
+// isa<X> - Return true if the parameter to the template is an instance of the
+// template type argument.  Used like this:
+//
+//  if (isa<Type>(myVal)) { ... }
+//
 template <class X, class Y>
-inline bool isa(const Y &Val) {
-  return isa_impl_cl<Y>::template isa<X>(Val);
+LLVM_ATTRIBUTE_UNUSED_RESULT inline bool isa(const Y &Val) {
+  return isa_impl_wrap<X, const Y,
+                       typename simplify_type<const Y>::SimpleType>::doit(Val);
 }
 
 //===----------------------------------------------------------------------===//
@@ -152,7 +179,7 @@ struct cast_retty_wrap<To, FromTy, FromTy> {
 
 template<class To, class From>
 struct cast_retty {
-  typedef typename cast_retty_wrap<To, From, 
+  typedef typename cast_retty_wrap<To, From,
                    typename simplify_type<From>::SimpleType>::ret_type ret_type;
 };
 
@@ -161,7 +188,7 @@ struct cast_retty {
 //
 template<class To, class From, class SimpleFrom> struct cast_convert_val {
   // This is not a simple type, use the template to simplify it...
-  static typename cast_retty<To, From>::ret_type doit(const From &Val) {
+  static typename cast_retty<To, From>::ret_type doit(From &Val) {
     return cast_convert_val<To, SimpleFrom,
       typename simplify_type<SimpleFrom>::SimpleType>::doit(
                           simplify_type<From>::getSimplifiedValue(Val));
@@ -171,33 +198,55 @@ template<class To, class From, class SimpleFrom> struct cast_convert_val {
 template<class To, class FromTy> struct cast_convert_val<To,FromTy,FromTy> {
   // This _is_ a simple type, just cast it.
   static typename cast_retty<To, FromTy>::ret_type doit(const FromTy &Val) {
-    return (typename cast_retty<To, FromTy>::ret_type)Val;
+    typename cast_retty<To, FromTy>::ret_type Res2
+     = (typename cast_retty<To, FromTy>::ret_type)const_cast<FromTy&>(Val);
+    return Res2;
   }
 };
 
-
+template <class X> struct is_simple_type {
+  static const bool value =
+      std::is_same<X, typename simplify_type<X>::SimpleType>::value;
+};
 
 // cast<X> - Return the argument parameter cast to the specified type.  This
 // casting operator asserts that the type is correct, so it does not return null
-// on failure.  But it will correctly return NULL when the input is NULL.
-// Used Like this:
+// on failure.  It does not allow a null argument (use cast_or_null for that).
+// It is typically used like this:
 //
 //  cast<Instruction>(myVal)->getParent()
 //
 template <class X, class Y>
-inline typename cast_retty<X, Y>::ret_type cast(const Y &Val) {
-  assert(isa<X>(Val) && "cast<Ty>() argument of uncompatible type!");
+inline typename std::enable_if<!is_simple_type<Y>::value,
+                               typename cast_retty<X, const Y>::ret_type>::type
+cast(const Y &Val) {
+  assert(isa<X>(Val) && "cast<Ty>() argument of incompatible type!");
+  return cast_convert_val<
+      X, const Y, typename simplify_type<const Y>::SimpleType>::doit(Val);
+}
+
+template <class X, class Y>
+inline typename cast_retty<X, Y>::ret_type cast(Y &Val) {
+  assert(isa<X>(Val) && "cast<Ty>() argument of incompatible type!");
   return cast_convert_val<X, Y,
                           typename simplify_type<Y>::SimpleType>::doit(Val);
 }
 
+template <class X, class Y>
+inline typename cast_retty<X, Y *>::ret_type cast(Y *Val) {
+  assert(isa<X>(Val) && "cast<Ty>() argument of incompatible type!");
+  return cast_convert_val<X, Y*,
+                          typename simplify_type<Y*>::SimpleType>::doit(Val);
+}
+
 // cast_or_null<X> - Functionally identical to cast, except that a null value is
 // accepted.
 //
 template <class X, class Y>
-inline typename cast_retty<X, Y*>::ret_type cast_or_null(Y *Val) {
-  if (Val == 0) return 0;
-  assert(isa<X>(Val) && "cast_or_null<Ty>() argument of uncompatible type!");
+LLVM_ATTRIBUTE_UNUSED_RESULT inline typename cast_retty<X, Y *>::ret_type
+cast_or_null(Y *Val) {
+  if (!Val) return nullptr;
+  assert(isa<X>(Val) && "cast_or_null<Ty>() argument of incompatible type!");
   return cast<X>(Val);
 }
 
@@ -207,85 +256,37 @@ inline typename cast_retty<X, Y*>::ret_type cast_or_null(Y *Val) {
 // be used to test for a type as well as cast if successful.  This should be
 // used in the context of an if statement like this:
 //
-//  if (const Instruction *I = dyn_cast<const Instruction>(myVal)) { ... }
+//  if (const Instruction *I = dyn_cast<Instruction>(myVal)) { ... }
 //
 
 template <class X, class Y>
-inline typename cast_retty<X, Y*>::ret_type dyn_cast(Y *Val) {
-  return isa<X>(Val) ? cast<X, Y*>(Val) : 0;
+LLVM_ATTRIBUTE_UNUSED_RESULT inline typename std::enable_if<
+    !is_simple_type<Y>::value, typename cast_retty<X, const Y>::ret_type>::type
+dyn_cast(const Y &Val) {
+  return isa<X>(Val) ? cast<X>(Val) : nullptr;
 }
 
-// dyn_cast_or_null<X> - Functionally identical to dyn_cast, except that a null
-// value is accepted.
-//
 template <class X, class Y>
-inline typename cast_retty<X, Y*>::ret_type dyn_cast_or_null(Y *Val) {
-  return (Val && isa<X>(Val)) ? cast<X, Y*>(Val) : 0;
-}
-
-
-#ifdef DEBUG_CAST_OPERATORS
-#include <iostream>
-
-struct bar {
-  bar() {}
-private:
-  bar(const bar &);
-};
-struct foo {
-  void ext() const;
-  /*  static bool classof(const bar *X) {
-    cerr << "Classof: " << X << "\n";
-    return true;
-    }*/
-};
-
-template <> inline bool isa_impl<foo,bar>(const bar &Val) { 
-  cerr << "Classof: " << &Val << "\n";
-  return true;
+LLVM_ATTRIBUTE_UNUSED_RESULT inline typename cast_retty<X, Y>::ret_type
+dyn_cast(Y &Val) {
+  return isa<X>(Val) ? cast<X>(Val) : nullptr;
 }
 
-
-bar *fub();
-void test(bar &B1, const bar *B2) {
-  // test various configurations of const
-  const bar &B3 = B1;
-  const bar *const B4 = B2;
-
-  // test isa
-  if (!isa<foo>(B1)) return;
-  if (!isa<foo>(B2)) return;
-  if (!isa<foo>(B3)) return;
-  if (!isa<foo>(B4)) return;
-
-  // test cast
-  foo &F1 = cast<foo>(B1);
-  const foo *F3 = cast<foo>(B2);
-  const foo *F4 = cast<foo>(B2);
-  const foo &F8 = cast<foo>(B3);
-  const foo *F9 = cast<foo>(B4);
-  foo *F10 = cast<foo>(fub());
-
-  // test cast_or_null
-  const foo *F11 = cast_or_null<foo>(B2);
-  const foo *F12 = cast_or_null<foo>(B2);
-  const foo *F13 = cast_or_null<foo>(B4);
-  const foo *F14 = cast_or_null<foo>(fub());  // Shouldn't print.
-  
-  // These lines are errors...
-  //foo *F20 = cast<foo>(B2);  // Yields const foo*
-  //foo &F21 = cast<foo>(B3);  // Yields const foo&
-  //foo *F22 = cast<foo>(B4);  // Yields const foo*
-  //foo &F23 = cast_or_null<foo>(B1);
-  //const foo &F24 = cast_or_null<foo>(B3);
+template <class X, class Y>
+LLVM_ATTRIBUTE_UNUSED_RESULT inline typename cast_retty<X, Y *>::ret_type
+dyn_cast(Y *Val) {
+  return isa<X>(Val) ? cast<X>(Val) : nullptr;
 }
 
-bar *fub() { return 0; }
-void main() {
-  bar B;
-  test(B, &B);
+// dyn_cast_or_null<X> - Functionally identical to dyn_cast, except that a null
+// value is accepted.
+//
+template <class X, class Y>
+LLVM_ATTRIBUTE_UNUSED_RESULT inline typename cast_retty<X, Y *>::ret_type
+dyn_cast_or_null(Y *Val) {
+  return (Val && isa<X>(Val)) ? cast<X>(Val) : nullptr;
 }
 
-#endif
+} // End llvm namespace
 
 #endif