src: introduce upx::ptr_reinterpret_cast

src/util/cxxlib.h

@@ -31,6 +31,24 @@
 
 namespace upx {
 
+/*************************************************************************
+// misc
+**************************************************************************/
+
+// a reinterpret_cast that does not trigger -Wcast-align warnings
+template <class Result, class From>
+forceinline Result ptr_reinterpret_cast(From *ptr) {
+    static_assert(std::is_pointer_v<Result>);
+    static_assert(!std::is_const_v<std::remove_pointer_t<Result> >); // enforce same constness
+    return (Result) (void *) ptr;
+}
+template <class Result, class From>
+forceinline Result ptr_reinterpret_cast(const From *ptr) {
+    static_assert(std::is_pointer_v<Result>);
+    static_assert(std::is_const_v<std::remove_pointer_t<Result> >); // required
+    return (Result) (const void *) ptr;
+}
+
 /*************************************************************************
 // type_traits
 **************************************************************************/

src/util/xspan.h

@@ -158,7 +158,7 @@ inline R *xspan_make_helper__(R * /*dummy*/, MemBuffer &mb) noexcept {
 #define XSPAN_S_VAR(type, var, first, ...) type *var = XSPAN_S_MAKE(type, (first))
 
 // cast to a different type (creates a new value)
-#define XSPAN_TYPE_CAST(type, x)           (reinterpret_cast<type *>(x))
+#define XSPAN_TYPE_CAST(type, x)           (upx::ptr_reinterpret_cast<type *>(x))
 // poison a pointer: point to a non-null invalid address
 #define XSPAN_INVALIDATE(x)                ptr_invalidate_and_poison(x)
 

src/util/xspan_impl_common.h

@@ -284,8 +284,8 @@ public:
     inline CSelf<U> type_cast() const {
         typedef CSelf<U> R;
         typedef typename R::pointer rpointer;
-        return R(R::Unchecked, reinterpret_cast<rpointer>(ptr), size_in_bytes,
-                 reinterpret_cast<rpointer>(base));
+        return R(R::Unchecked, upx::ptr_reinterpret_cast<rpointer>(ptr), size_in_bytes,
+                 upx::ptr_reinterpret_cast<rpointer>(base));
     }
 
     bool operator==(pointer other) const noexcept { return ptr == other; }

src/util/xspan_impl_ptr.h

@@ -127,7 +127,7 @@ public:
     inline CSelf<U> type_cast() const {
         typedef CSelf<U> R;
         typedef typename R::pointer rpointer;
-        return R(reinterpret_cast<rpointer>(ptr));
+        return R(upx::ptr_reinterpret_cast<rpointer>(ptr));
     }
 
     // comparison