X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FSupport%2FCasting.h;h=720c34f7b4913103452da1414f0eaa3e0a2d2dea;hb=bef2236283c333f17613b2ea4904878228fedb6e;hp=e59b7c2d07681611d2138455c0423f8079a05032;hpb=589df88ba03a81b2b3dc9d084c191a3a74724ecd;p=oota-llvm.git

diff --git a/include/llvm/Support/Casting.h b/include/llvm/Support/Casting.h
index e59b7c2d076..720c34f7b49 100644
--- a/include/llvm/Support/Casting.h
+++ b/include/llvm/Support/Casting.h
@@ -1,58 +1,256 @@
-//===-- 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
 
-// real_type - Provide a macro to get the real type of a value that might be 
-// a use.  This provides a typedef 'Type' that is the argument type for all
-// non UseTy types, and is the contained pointer type of the use if it is a
-// UseTy.
-//
-template <class X> class real_type { typedef X Type; };
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/type_traits.h"
+#include <cassert>
+
+namespace llvm {
 
 //===----------------------------------------------------------------------===//
-//                          Type Checking Templates
+//                          isa<x> Support Templates
 //===----------------------------------------------------------------------===//
 
+// 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.
+//
+template<typename From> struct simplify_type {
+  typedef       From SimpleType;        // The real type this represents...
+
+  // An accessor to get the real value...
+  static SimpleType &getSimplifiedValue(From &Val) { return Val; }
+};
+
+template<typename From> struct simplify_type<const From> {
+  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);
+  }
+};
+
+/// \brief Always allow upcasts, and perform no dynamic check for them.
+template <typename To, typename From>
+struct isa_impl<To, From,
+                typename enable_if<
+                  llvm::is_base_of<To, From>
+                >::type
+               > {
+  static inline bool doit(const From &) { return true; }
+};
+
+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 From> struct isa_impl_cl<To, const From> {
+  static inline bool doit(const From &Val) {
+    return isa_impl<To, From>::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);
+  }
+};
+
+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);
+  }
+};
+
+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);
+  }
+};
+
+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(Y Val) {
-  assert(Val && "isa<Ty>(NULL) invoked!");
-  return X::classof(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);
 }
 
+//===----------------------------------------------------------------------===//
+//                          cast<x> Support Templates
+//===----------------------------------------------------------------------===//
+
+template<class To, class From> struct cast_retty;
+
+
+// Calculate what type the 'cast' function should return, based on a requested
+// type of To and a source type of From.
+template<class To, class From> struct cast_retty_impl {
+  typedef To& ret_type;         // Normal case, return Ty&
+};
+template<class To, class From> struct cast_retty_impl<To, const From> {
+  typedef const To &ret_type;   // Normal case, return Ty&
+};
+
+template<class To, class From> struct cast_retty_impl<To, From*> {
+  typedef To* ret_type;         // Pointer arg case, return Ty*
+};
+
+template<class To, class From> struct cast_retty_impl<To, const From*> {
+  typedef const To* ret_type;   // Constant pointer arg case, return const Ty*
+};
+
+template<class To, class From> struct cast_retty_impl<To, const From*const> {
+  typedef const To* ret_type;   // Constant pointer arg case, return const Ty*
+};
+
+
+template<class To, class From, class SimpleFrom>
+struct cast_retty_wrap {
+  // When the simplified type and the from type are not the same, use the type
+  // simplifier to reduce the type, then reuse cast_retty_impl to get the
+  // resultant type.
+  typedef typename cast_retty<To, SimpleFrom>::ret_type ret_type;
+};
+
+template<class To, class FromTy>
+struct cast_retty_wrap<To, FromTy, FromTy> {
+  // When the simplified type is equal to the from type, use it directly.
+  typedef typename cast_retty_impl<To,FromTy>::ret_type ret_type;
+};
+
+template<class To, class From>
+struct cast_retty {
+  typedef typename cast_retty_wrap<To, From,
+                   typename simplify_type<From>::SimpleType>::ret_type ret_type;
+};
+
+// Ensure the non-simple values are converted using the simplify_type template
+// that may be specialized by smart pointers...
+//
+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(From &Val) {
+    return cast_convert_val<To, SimpleFrom,
+      typename simplify_type<SimpleFrom>::SimpleType>::doit(
+                          simplify_type<From>::getSimplifiedValue(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) {
+    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 =
+      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()
-//  cast<const Instruction>(myVal)->getParent()
+//  cast<Instruction>(myVal)->getParent()
 //
 template <class X, class Y>
-inline X *cast(Y Val) {
-  assert(isa<X>(Val) && "cast<Ty>() argument of uncompatible type!");
-  return (X*)(real_type<Y>::Type)Val;
+inline typename enable_if_c<!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 X *cast_or_null(Y Val) {
-  assert((Val == 0 || isa<X>(Val)) &&
-         "cast_or_null<Ty>() argument of uncompatible type!");
-  return (X*)(real_type<Y>::Type)Val;
+LLVM_ATTRIBUTE_UNUSED_RESULT 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 incompatible type!");
+  return cast<X>(Val);
 }
 
 
@@ -61,11 +259,25 @@ inline X *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 X *dyn_cast(Y Val) {
+LLVM_ATTRIBUTE_UNUSED_RESULT inline typename enable_if_c<
+    !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) : 0;
+}
+
+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) : 0;
+}
+
+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) : 0;
 }
 
@@ -73,8 +285,11 @@ inline X *dyn_cast(Y Val) {
 // value is accepted.
 //
 template <class X, class Y>
-inline X *dyn_cast_or_null(Y Val) {
+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) : 0;
 }
 
+} // End llvm namespace
+
 #endif