X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FSupport%2FCasting.h;h=d35febbe6d80b979bcb119c2a0d993a83687d2f8;hb=2fa8af224ea026f9432e833fd6f42a216423a010;hp=6bb98064382e3f06a0cb219f9d124cd2d5830919;hpb=ce31f40295a0cd42f5df32f6295cf334a3a6df76;p=oota-llvm.git

diff --git a/include/llvm/Support/Casting.h b/include/llvm/Support/Casting.h
index 6bb98064382..d35febbe6d8 100644
--- a/include/llvm/Support/Casting.h
+++ b/include/llvm/Support/Casting.h
@@ -23,8 +23,6 @@ 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.
@@ -43,12 +41,9 @@ template<typename From> struct simplify_type<const From> {
   }
 };
 
-
-// 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)) { ... }
-//
+// 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>
 struct isa_impl {
   static inline bool doit(const From &Val) {
@@ -56,66 +51,66 @@ struct isa_impl {
   }
 };
 
-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>::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);
   }
 };
 
-// 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 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);
 }
 
 //===----------------------------------------------------------------------===//
@@ -192,8 +187,8 @@ 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()
 //