Added type_hash<T>(): Creates a (mostly) unique SHA256 hash at compile time for a given type. The hash is given static storage duration, no other executable bloat is kept.

XXX: Added new dependency: `sha256_literal`. (TODO: Grab this, manage dependencies somehow..)

Added id.hh: `uuid` and related types & helpers.

Fortune for readpass's current commit: Future small blessing − 末小吉

include/alloc.h

@@ -4,6 +4,7 @@
 
 #ifdef __cplusplus
 #include <memory>
+#include <pair>
 #endif
 
 #include "constraints.hh"
@@ -38,80 +39,82 @@ namespace alloc {
 			constexpr deleter(deleter&&) noexcept = default;
 			constexpr deleter& operator=(deleter&&) noexcept = default;
 
-			constexpr void operator()(void* restrict p) const noexcept { return apply_delete(p); }
+			[[gnu::nonnull(2)]]
+			constexpr void operator()(void* restrict p) const noexcept { apply_delete(p); }
 
 			virtual ~deleter();
 		protected:
 			explicit deleter(std::shared_ptr<anon_raw_secmem>&& p);
 
-			template<where::is_polymorphic T>
-			constexpr static void* erase_type(T* ptr) noexcept { return dynamic_cast<void*>(ptr); }
-			template<where::is_polymorphic T>
-			constexpr static void const* erase_type(T const* ptr) noexcept { return dynamic_cast<void const*>(ptr); }
-			template<typename T>
-			constexpr static void* erase_type_unsafe(T* ptr) noexcept { return static_cast<void*>(ptr); }
-			template<typename T>
-			constexpr static T* add_type_unsafe(void* ptr) noexcept { return static_cast<T*>(ptr); }
-			template<typename T>
-			constexpr static void const* erase_type_unsafe(T const* ptr) noexcept { return static_cast<void const*>(ptr); }
-			template<typename T>
-			constexpr static T const* add_type_unsafe(void const* ptr) noexcept { return static_cast<T const*>(ptr); }
+			[[gnu::nonnull(2)]]
+			virtual std::pair<void*> apply_delete(void* restrict, bool = true) const noexcept;
+			virtual void scramble_memory(std::initializer_list<std::pair<void*>> ptrs) const noexcept;
+			inline void scramble_memory(std::pair<void*> ptr) const noexcept { return scramble_memory({ ptr }); }
 
-			virtual void apply_delete(void* restrict, bool = true) const noexcept;
-
-			inline deleter* finalizer_group_id() const noexcept {
-				return m_group_ptr ?: static_cast<deleter*>(this);
-			}
-			// See dtor impl
-			void apply_finalizer_group(std::initializer_list<void*> = {}) noexcept;
-			void apply_finalizer_now(std::initializer_list<void*> = {}) noexcept;
 
 			// To prevent anon_raw_secmem being destroyed while there are still allocated values, the base class for the deleter for those values contains a refcount. e.g: `std::unique_ptr<T, deleter_for<T>>` where: `deleter_for<T> final : public deleter { virtual ~deleter_for(); ... };`, or `std::shared_ptr<T>`, where: `std::shared_ptr<value_with_deleter<T>>` aliases-ctor(`old, old->value_ptr()`) -> `std::shared_ptr<T>`
 			std::shared_ptr<anon_raw_secmem> m_manager_ref;
-		private:
-			// Used to sync `this`'s group across copies.
-			deleter*  m_group_ptr;
 		};
+		struct alloc_vt;
 		struct alloc_info;
 		struct alloc_value;
 
+		template<typename>
+		struct deleter_for; 	
+		template<typename>
+		struct deleter_for_value;
+	public:
+		FrozenAllocator(FrozenAllocator &&) noexcept;
+		FrozenAllocator& operator=(FrozenAllocator &&);
+
+		FrozenAllocator(const FrozenAllocator&) = delete;
+		FrozenAllocator& operator=(const FrozenAllocator&) = delete;
+		virtual ~FrozenAllocator();
+	private:
+		std::unique_ptr<_impl> inner_;
+
+		/// Manages everything about the actual allocations
+		//std::shared_ptr<anon_raw_secmem> m_manager;
+		/// A map of values inside the allocator. This is destroyed in reverse order, meaning all the living values are destroyed *before* `m_manager`'d destruction deallocates them.
+		//std::map<alloc_info, std::unique_ptr<alloc_value, deleter>> m_values;
+	};
 	template<typename T>
-		struct deleter_for : virtual deleter {
+	struct FrozenAllocator::deleter_for 
+		: virtual deleter 
+	{
 		inline deleter_for(std::shared_ptr<anon_raw_secmem>&& m)
 			: deleter(std::move(m)) {}
 		virtual ~deleter_for() = default; // This will use deleter's dtor to remove allocations.
 
-			inline void operator()(T* ptr) const noexcept { return apply_delete(deleter::erase_type_unsafe(ptr)); }
+		[[gnu::nonnull(2)]]
+		inline void operator()(T* ptr) const noexcept { apply_delete(deleter::erase_type_unsafe(ptr)); }
 
 	protected:
 		inline virtual void apply_delete_typed(T* ptr) const noexcept {
 			ptr->~T();
 		}
 	private:
-			inline void apply_delete(void* restrict up) const noexcept override final {
+		[[gnu::nonnull(2)]]
+		inline std::pair<void*> apply_delete(void* restrict up) const noexcept override final {
 			if constexpr(std::is_trivially_destructible_v<T>) {
-					deleter::apply_delete(up); // If the dtor is trivial, ignore it and use default behaviour.
+				return deleter::apply_delete(up); // If the dtor is trivial, ignore it and use default behaviour.
 			} else {
-					deleter::apply_delete(up, false); // Unlock the memory, but do *not* add it to this deleter's finalizer group.
-					apply_delete_typed(static_cast<T*>(up)); // Apply the destructor for `T`
-					deleter::apply_finalizer_now({up}); // Get `anon_raw_secmem` to deallocate the memory *now*, instead of at destruction.
+				auto pair = deleter::apply_delete(up, false); // Unlock the memory and remove the allocation from `anon_raw_secmem`, but do *not* bzero it.
+				apply_delete_typed(static_cast<T*>(up)); // Apply the destructor for `T` to the alligned pointer `up`.
+				deleter::scramble_memory(pair); // *now* bzero the unaligned pointer (full range, including alignment padding.)
+				return pair;
 			}
 		}
 	};
-	public:
-		FrozenAllocator(FrozenAllocator &&) noexcept;
-		FrozenAllocator& operator=(FrozenAllocator &&);
+	template<typename T>
+	struct FrozenAllocator::deleter_for_value final : deleter_for<T> {
+		//TODO: Re-work this? Is it useful? Is it needed?
 
-		FrozenAllocator(const FrozenAllocator&) = delete;
-		FrozenAllocator& operator=(const FrozenAllocator&) = delete;
-		virtual ~FrozenAllocator();
+		inline virtual ~deleter_for_value() {
+			deleter_for<T>::apply_delete(m_value_ptr);
+		}
 	private:
-		std::unique_ptr<_impl> inner_;
-
-		/// Manages everything about the actual allocations
-		//std::shared_ptr<anon_raw_secmem> m_manager;
-		/// A map of values inside the allocator. This is destroyed in reverse order, meaning all the living values are destroyed *before* `m_manager`'d destruction deallocates them.
-		//std::map<alloc_info, std::unique_ptr<alloc_value, deleter>> m_values;
+		T* m_value_ptr;
 	};
 }
 #endif

include/id.hh

@@ -0,0 +1,45 @@
+#pragma once
+
+namespace id {
+	struct uuid {
+		//TODO: constexpr uuid_v4 impl
+
+		constexpr uuid v4() noexcept {
+			//TODO: Generate new UUID at compile time?
+		}
+	};
+	struct unique_ref {
+		uuid id;
+
+		constexpr friend auto operator<=>(unique_ref const& a, unique_ref const& b) noexcept = default;
+	};
+	struct unique {
+		constexpr unique() noexcept
+			: m_id(uuid::v4()) {}
+		constexpr unique(const unique&) noexcept
+			: unique() {}
+		constexpr unique(unique&&) noexcept = default;
+		constexpr unique& operator=(unique&&) noexcept = default;
+		constexpr unique& operator=(unique const& b) noexcept
+		{ if(this != std::addressof(b)) m_id = uuid::v4(); return *this; }
+		constexpr virtual ~unique() = default;
+
+		template<std::derived_from<unique> T, std::derived_from<unique> U>
+		constexpr friend bool operator==(T const& a, U const& b) noexcept { return static_cast<unique const&>(a) == static_cast<unique const&>(b); }
+		template<std::derived_from<unique> T, std::derived_from<unique> U>
+		constexpr friend bool operator!=(T const& a, U const& b) noexcept { return !(a == b); }
+
+		constexpr friend bool operator==(unique const& a, unique const& b) noexcept { return a.unique_id() == b.unique_id(); }
+		constexpr friend bool operator!=(unique const& a, unique const& b) noexcept { return a.unique_id() != b.unique_id(); }
+
+		constexpr unique_ref unique_id() const noexcept { return { m_id }; }
+	protected:
+		constexpr uuid& raw_id() noexcept { return m_id; }
+		constexpr uuid const& raw_id() const noexcept { return m_id; }
+
+		constexpr explicit unique(std::convertible_to<uuid> auto&& id)
+			: m_id(std::move(id)) {}
+	private:
+		uuid m_id;
+	};
+}

include/macros.h

@@ -41,6 +41,8 @@
 
 #define unrestrict __attribute__((__may_alias__))
 
+#define ASSUME(X) ({ if(!(X)) __builtin_unreachable(); (void)0; })
+
 #if $CXX
 #define $READ_ONCE_FROM(...) [&] () noexcept -> auto { using cvx_t = ::std::add_pointer_t<::std::add_const_t<::std::add_volatile_t<decltype(__VA_ARGS__)>>>; \
 					return *static_cast<cvx_t>(::std::addressof(__VA_ARGS__)); \

include/types.hh

@@ -1,3 +1,29 @@
 #pragma once
 
-//TODO: A very basic typeid: Using the constexpr __PRETTY_FUNCTION__ array slicing trick we used for `exopt::util::type_name<T>()`, we can extract the unmangled, de-aliased type name T, we can then hash that at comptime, and give it static storage: Therefore __PRETTY_FUNCTION__ will not be given storage, but the resulting (far smaller, but still *almost* unique to each type name) hash, will be.
+#include <sha256_literal.h>
+
+#include "util.hh"
+
+namespace types {
+	// A very basic typeid: Using the constexpr __PRETTY_FUNCTION__ array slicing trick we used for `exopt::util::type_name<T>()`, we can extract the unmangled, de-aliased type name T, we can then hash that at comptime, and give it static storage: Therefore __PRETTY_FUNCTION__ will not be given storage, but the resulting (far smaller, but still *almost* unique to each type name) hash, will be.
+
+	using util::type_name;
+
+	template<typename T>
+	struct type_hash_of {
+		// Give *only* the computed hash static storage duration, not the type name.
+		constexpr static inline auto value = sha256::compute(util::type_name_literal<T>());
+	};
+
+	/// Returns a (semi) unique SHA256 hash representing the type `T`.
+	/// 
+	/// NOTE: This hash is given static storage duration, but nothing else used to calculate it is. Therefore executable bloat is not a concern for values obtained from this function.
+	template<typename T>
+	constexpr const auto& type_hash() noexcept {
+		constexpr const auto& value = type_hash_of<T>::value;
+		return value;
+	}
+
+	template<typename T>
+	constexpr inline auto& type_hash_v = type_hash_of<T>::value;
+}

include/util.hh

@@ -0,0 +1,80 @@
+#pragma once
+
+#include <utility>
+#include <pointer_traits>
+#include <array>
+
+#include <cstddef>
+
+namespace util {
+	[[gnu::const, gnu::always_inline]]
+	constexpr ptrdiff_t ptr_diff(const auto *p1, const auto *p2) noexcept
+	{
+		auto a1 = std::to_address(p1);
+		auto a2 = std::to_address(p2);
+		return ptrdiff_t(a1 < a2 ? a2 - a1 : a1 - a2);
+	}
+	[[gnu::const, gnu::always_inline]]
+	constexpr ptrdiff_t ptr_diff(intptr_t p1, intptr_t p2) noexcept
+	{
+		return ptrdiff_t(p1 < p2 ? p2 - p1 : p1 - p2);
+	}
+
+
+	template<size_t... Idx>
+	constexpr auto substring_literal(const auto& str, std::index_sequence<Idx...>) noexcept
+		requires(requires(size_t n) { 
+			{ str[n] } noexcept -> std::convertible_to<char>;
+		})
+	{
+		return std::array{ str[Idx]..., '\n' };
+	}
+
+	template<typename T>
+	constexpr auto type_name_literal() noexcept 
+	{
+		constexpr std::string_view prefix	{
+#if defined(__clang__)
+			"[T = "
+#elif defined(__GNUC__)
+			"with T = "
+#else
+// Fuck MSVC, don't care.
+#error Unsupported compiler
+#endif
+		};
+		constexpr std::string_view suffix	{"]"};
+		constexpr std::string_view function	{__PRETTY_FUNCTION__};
+
+		constexpr auto start = function.find(prefix) + prefix.size();
+		constexpr auto end = function.rfind(suffix);
+
+		static_assert(start < end);
+
+		constexpr std::string_view name = function.substr(start, (end - start));
+		return substring_literal(name, std::make_index_sequence<name.size()>{});
+	}
+
+	template<typename T>
+	struct [[gnu::visibility("internal")]] type_name_of {
+		constexpr static inline auto value = type_name_literal<T>();
+
+		[[gnu::const]]
+		consteval operator std::string_view() const noexcept {
+			constexpr auto& v = value;
+			return std::string_view { v.data(), v.size() };
+		}
+	};
+
+	template<typename T>
+	constexpr auto type_name() noexcept -> std::string_view
+	{
+		constexpr auto& value = type_name_of<T>::value;
+		return std::string_view { value.data(), value.size() };
+	}
+
+	template<typename T>
+	constexpr inline auto type_name_v = type_name<T>();
+
+
+}

src/alloc.cpp

@@ -2,8 +2,24 @@
 
 #include <map>
 
+#include <cstring>
+
+
 #include <alloc.h>
 
+#include <util.hh>
+#include <types.hh>
+#include <macros.h>
+
+template<typename T = int>
+using type_hash_t = decltype(types::type_hash<int>());
+
+template<typename T = int>
+using type_hash_ref = std::remove_reference_t<type_hash_t<T>> const&;
+
+template<typename T = int>
+using type_hash_ptr = std::remove_reference_t<type_hash_t<T>> const*;
+
 extern "C" {
 	base_allocator::~base_allocator() {}
 }
@@ -12,59 +28,120 @@ namespace alloc {
 
 	// Base class for all deallocations that happen within an `anon_raw_secmem` (managed, static, polymorphic, unmanaged, etc.) (TODO: See below, the base should be moved into the header so typed children can be templated...)
 	FrozenAllocator::deleter::~deleter() {
-		apply_finalizer_group();
-	}
-	FrozenAllocator::deleter::deleter(std::shared_ptr<anon_raw_secmem>&& p)
-		: m_manager_ref(std::move(p))
-		, m_gorup_ptr(static_cast<deleter*>(this)) {} //TODO:XXX: Do we actually need finalizer groups now? (see note below about `m_values`.
-
-	void FrozenAllocator::deleter::apply_finalizer_group(std::initializer_list<void*> ptrs) noexcept {
-		if(ptrs.empty()) {
+		//apply_finalizer_group(); // XXX: Do we actually need finalizer groups now? (see note below about `m_values`.
 
-			//TODO: auto&& fgroup = std::move(m_manager_ref->get_finalizer_group_for(finalizer_group_id())); // The *whole* finalizer group, *moved* from `m_manager_ref`. (which leaves finalizer_group for `this` empty now.)
-			//TODO: `bzero_explicit()` the memory from the allocations, then tell `anon_raw_secmem` to mark is as free.
-		} else {
-	
-			//TODO: auto& fgroup = m_manager_ref->get_finalizer_group_ref_for(finalizer_group_id()); // The whole finalizer group, *referenced* from `m_manager_ref`. (which leaves finalizer_group for `this` intact, removal of pointers from the group will have to happen below manually.)
-			for(void* p : ptrs) {
-				//TODO: Do the same as above, but only for pointers registered for finalizing in `ptrs`.
-			}
 	}
+	FrozenAllocator::deleter::deleter(std::shared_ptr<anon_raw_secmem>&& p)
+		: m_manager_ref(std::move(p)) {}
+		// , m_gorup_ptr(static_cast<deleter*>(this)) {}
+
+
+	void scramble_memory(std::initializer_list<std::pair<void*>> ptrs) const noexcept
+	{
+		for(auto [ps, pe] : ptrs) {
+			// ps: start of range, pe: end of range (or nullptr, if range must be looked up in `m_manager_ref`.)
+			if(UNLIKELY(!pe)) {
+				if(const auto& alloc = m_manager_ref->lookup_alloc(ps))
+					pe = alloc.range().second;
+				else	continue;
 			}
+			else if(UNLIKELY(ps == pe)) continue;
 
-	/// Instead of acting on pointers in `this`'s finalizer group, immediately get `anon_raw_secmem` to perform the deallocation and map-removal on these `ptrs`.
-	void apply_finalizer_now(std::initializer_list<void*> ptrs) noexcept {
-		for(void* p : ptrs) {
-			//TODO: `m_manager_ref->immediate_dealloc(p)`
+			intptr_t psa = std::to_address(ps),
+				pea = std::to_address(pe);
+			ASSUME(pea > psa);
+			explicit_bzero(ps, util::ptr_diff(psa, pea));	
 		}
 	}
-	void FrozenAllocator::deleter::apply_delete(void* restrict p, bool add_group) const noexcept {
-		// TODO: allow the allocation (the memory corresponding to `p` from `m_manager_ref`) to be mutable (`munlock()` it.)
-		// TODO: Then, again through `m_manager_ref`, add to sequence `->register_finalizer_grouped(this, p)`.
-		/// TODO: Unless `add_group` is `false`, in which case, `p` is left to dangle.
 
+	[[gnu::nonnull(2)]]
+	std::pair<void*> FrozenAllocator::deleter::apply_delete(void* restrict p, bool clean) const noexcept {
 		//(XXX: NOTE: `m_values` map removal *causes* this to be invoked, i.e: A value removed from the map calls `deleter::operator()(uniq_p)`, which then calls `apply_delete(uniq_p, true)`
+
+		// Lookup the allocation info for pointer `p`.
+		const auto& alloc = m_manager_ref->lookup_alloc(p);
+		if(UNLIKELY(!alloc)) return {p, p};
+
+		// TODO: allow the allocation (the memory corresponding to `p` from `m_manager_ref`) to be mutable (`munlock()` it.)
+		
+		// Get the full range (including alignment padding) 
+		auto al_range = alloc.range();
+		// Then, if `clean == true` (default), `bzero_explicit()` the memory (range for `p` obtained from `m_manager_ref`.)
+		if(LIKELY(clean)) scramble_memory(al_range);
+
+		// Return the range (or the end pointer of `p`'s range for use in / as an iterator.)
+		return al_range;
 	}
 	// This is the *true manager* of the allocation arena, when it is destroyed, the memory is cleared
-	struct FrozenAllocator::anon_raw_secmem {
-		typedef FrozenAllocator::deleter deleter;
+	struct FrozenAllocator::anon_raw_secmem final
+			: virtual id::unique
+	{
+		// Deleter that works on `alloc_value`s directly
+		struct deleter final : public deleter_for<alloc_value> {
+			//TODO: This ^
+		private:
+			void apply_delete_typed(alloc_value* ptr) const noexcept override {
+				//TODO: Destroy the typed object inside `ptr`. (XXX: Where should destructor info be kept? In `alloc_value` or `alloc_info`? I think `alloc_value`.
+	
+				// Run `alloc_value` itself's dtor now.	
+				deleter_for<alloc_value>::apply_delete_typed(ptr);
+			}
+		};
 
-		~anon_raw_secmem() {
+		virtual ~anon_raw_secmem() {
 			//TODO: Clear and `munmap()` the used page(s)
 			//XXX: Due to how this is managed via `shared_ptr<>`, it is UB for this to be called *before* all actual allocation of the memory are unallocated (via `deleter`, which they must *all* be managed by.
 		}
 	};
 
 	struct FrozenAllocator::alloc_info {
+		id::uuid alloc_id; // ID of this allocation 
+		id::unique_ref owner; // Reference to the unique ID of the `anon_raw_secmem` that manages this allocation.
+
+		type_hash_ptr type; // Static pointer to the `types::type_hash<T>()` result of the `T` that this allocation is. (Basic RTTI: `type_hash_t` should only exist in static storage, otherwise we use `type_hash_ref` or `type_hash_ptr`.)
 
+		struct {
+			size_t size, align;
+		} meta;
+
+		void* area_start;
+		void* area;
 	};
 	struct FrozenAllocator::alloc_value {
-
+		typedef bool (*vt_ctor)(alloc_value* to, ...);
+		typedef bool (*vt_copy)(const alloc_value& from, alloc_value* to);
+		typedef bool (*vt_move)(alloc_value&& from, alloc_value* to);
+		typedef bool (*vt_assign_copy)(const alloc_value& from, alloc_value* to);
+		typedef bool (*vt_assign_move)(alloc_value&& from, alloc_value* to);
+		typedef bool (*vt_destroy)(alloc_value* obj);
+		typedef void* (*vt_this)(const alloc_value& from);
+		typedef bool (*vt_cast_into)(const alloc_value& a, alloc_value* b);
+		/// vt_type_info: if info not null: return if `a` is type referred to in `info`, else if `type` not null: set `*type` to be type of `a`, return false if that is not possible with the other arguments given.
+		typedef bool (*vt_type_info)(const alloc_value& a, const alloc_info* info, type_hash_ptr *restrict type);
+
+		//TODO: How to create? Overloaded operator placement new, inside `alloc_info` or `anon_raw_secmem`? Since the storage for these are allocated and managed *by* `anon_raw_secmem`, that would make the most sense I think... `alloc_info` holds the pointer to the specific allocation, its ID, etc; stuff for ordered allocation lookup. This is managed (entirely) by `anon_raw_secmem`, and `std::unique_ptr<alloc_value, anon_raw_secmem::deleter>` ensures it is not deleted naturally, but only removed from `anon_raw_secmem`.
+
+		//! Basic RTTI impl that holds type-erased, alignment padded values and gives out aligned void* pointers to it.
+		//! NOTE: This class does *not* apply any destructor when destroyed, `anon_raw_secmem::deleter` should be used for that.
+		struct {
+			struct {
+				vt_ctor		_create;
+				vt_copy		_copy;
+				vt_move		_move;
+				vt_destroy	_destroy;
+				vt_this 	_this;
+				vt_type_info	_typeinfo;
+				// We don't need the others, they can be constructed by combining calls to these. (e.g.: assign_copy(new, old) =  `destroy(old), copy(new, old)`.)
+			} vt;
+			size_t size, align;
+		} meta;
+
+		unsigned char data[];
 	};
 
 	struct FrozenAllocator::_impl {
 		std::shared_ptr<anon_raw_secmem> m_manager;
-		std::map<alloc_info, std::unique_ptr<alloc_value, deleter>> m_values;
+		std::map<alloc_info, std::unique_ptr<alloc_value, anon_raw_secmem::deleter>> m_values;
 	};
 
 #define $CLASS FrozenAllocator