X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FSupport%2FCasting.h;h=0c71882a77b1fc1952faf52c2e5c0420c035bc26;hb=b09c146b116359616f6cbd4c8b3328607e00ff42;hp=c441626216f16b92dccb57dcee66f7802a01ad2c;hpb=bab6436b1726a2db21ab1e024540e98c02a5a009;p=oota-llvm.git

diff --git a/include/llvm/Support/Casting.h b/include/llvm/Support/Casting.h
index c441626216f..0c71882a77b 100644
--- a/include/llvm/Support/Casting.h
+++ b/include/llvm/Support/Casting.h
@@ -15,6 +15,7 @@
 #ifndef LLVM_SUPPORT_CASTING_H
 #define LLVM_SUPPORT_CASTING_H
 
+#include "llvm/Support/type_traits.h"
 #include <cassert>
 
 namespace llvm {
@@ -23,8 +24,6 @@ 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.
@@ -43,77 +42,86 @@ template<typename From> struct simplify_type<const From> {
   }
 };
 
+// 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 llvm::enable_if_c<
+                  llvm::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
-// canonical 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);
   }
 };
 
-// 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 (Val != 0 && 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<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);
+  return isa_impl_wrap<X, Y, typename simplify_type<Y>::SimpleType>::doit(Val);
 }
 
 //===----------------------------------------------------------------------===//
@@ -180,8 +188,9 @@ 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 reinterpret_cast<typename cast_retty<To, FromTy>::ret_type>(
-                         const_cast<FromTy&>(Val));
+    typename cast_retty<To, FromTy>::ret_type Res2
+     = (typename cast_retty<To, FromTy>::ret_type)const_cast<FromTy&>(Val);
+    return Res2;
   }
 };
 
@@ -189,8 +198,8 @@ template<class To, class FromTy> struct cast_convert_val<To,FromTy,FromTy> {
 
 // 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()
 //
@@ -229,75 +238,10 @@ inline typename cast_retty<X, Y>::ret_type dyn_cast(const Y &Val) {
 // value is accepted.
 //
 template <class X, class Y>
-inline typename cast_retty<X, Y>::ret_type dyn_cast_or_null(const Y &Val) {
-  return (Val && isa<X>(Val)) ? cast<X, Y>(Val) : 0;
+inline typename cast_retty<X, Y*>::ret_type dyn_cast_or_null(Y *Val) {
+  return (Val && isa<X>(Val)) ? cast<X>(Val) : 0;
 }
 
-
-#ifdef DEBUG_CAST_OPERATORS
-#include "llvm/Support/Streams.h"
-
-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;
-}
-
-
-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);
-}
-
-bar *fub() { return 0; }
-void main() {
-  bar B;
-  test(B, &B);
-}
-
-#endif
-
 } // End llvm namespace
 
 #endif