From b3c8997829ed986c948d195bc1e7c8f66c42755e Mon Sep 17 00:00:00 2001
From: Lioncash <mathew1800@gmail.com>
Date: Tue, 17 Nov 2020 19:58:41 -0500
Subject: page_table: Allow page tables to be moved

Makes page tables and virtual buffers able to be moved, but not copied,
making the interface more flexible.

Previously, with the destructor specified, but no move assignment or
constructor specified, they wouldn't be implicitly generated.
---
 src/common/virtual_buffer.h | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

(limited to 'src/common/virtual_buffer.h')

diff --git a/src/common/virtual_buffer.h b/src/common/virtual_buffer.h
index 125cb42f0..363913d45 100644
--- a/src/common/virtual_buffer.h
+++ b/src/common/virtual_buffer.h
@@ -4,25 +4,38 @@
 
 #pragma once
 
-#include "common/common_funcs.h"
+#include <utility>
 
 namespace Common {
 
-void* AllocateMemoryPages(std::size_t size);
-void FreeMemoryPages(void* base, std::size_t size);
+void* AllocateMemoryPages(std::size_t size) noexcept;
+void FreeMemoryPages(void* base, std::size_t size) noexcept;
 
 template <typename T>
-class VirtualBuffer final : NonCopyable {
+class VirtualBuffer final {
 public:
     constexpr VirtualBuffer() = default;
     explicit VirtualBuffer(std::size_t count) : alloc_size{count * sizeof(T)} {
         base_ptr = reinterpret_cast<T*>(AllocateMemoryPages(alloc_size));
     }
 
-    ~VirtualBuffer() {
+    ~VirtualBuffer() noexcept {
         FreeMemoryPages(base_ptr, alloc_size);
     }
 
+    VirtualBuffer(const VirtualBuffer&) = delete;
+    VirtualBuffer& operator=(const VirtualBuffer&) = delete;
+
+    VirtualBuffer(VirtualBuffer&& other) noexcept
+        : alloc_size{std::exchange(other.alloc_size, 0)}, base_ptr{std::exchange(other.base_ptr),
+                                                                   nullptr} {}
+
+    VirtualBuffer& operator=(VirtualBuffer&& other) noexcept {
+        alloc_size = std::exchange(other.alloc_size, 0);
+        base_ptr = std::exchange(other.base_ptr, nullptr);
+        return *this;
+    }
+
     void resize(std::size_t count) {
         FreeMemoryPages(base_ptr, alloc_size);
 
-- 
cgit v1.2.3


From 0ca91ced2dab3654e78e4c465506d7baad3cbeeb Mon Sep 17 00:00:00 2001
From: Lioncash <mathew1800@gmail.com>
Date: Tue, 17 Nov 2020 20:09:55 -0500
Subject: virtual_buffer: Add compile-time type-safety guarantees with
 VirtualBuffer

VirtualBuffer makes use of VirtualAlloc (on Windows) and mmap() (on
other platforms). Neither of these ensure that non-trivial objects are
properly constructed in the allocated memory.

To prevent potential undefined behavior occurring due to that, we can
add a static assert to loudly complain about cases where that is done.
---
 src/common/virtual_buffer.h | 6 ++++++
 1 file changed, 6 insertions(+)

(limited to 'src/common/virtual_buffer.h')

diff --git a/src/common/virtual_buffer.h b/src/common/virtual_buffer.h
index 363913d45..078e61c77 100644
--- a/src/common/virtual_buffer.h
+++ b/src/common/virtual_buffer.h
@@ -4,6 +4,7 @@
 
 #pragma once
 
+#include <type_traits>
 #include <utility>
 
 namespace Common {
@@ -14,6 +15,11 @@ void FreeMemoryPages(void* base, std::size_t size) noexcept;
 template <typename T>
 class VirtualBuffer final {
 public:
+    static_assert(
+        std::is_trivially_constructible_v<T>,
+        "T must be trivially constructible, as non-trivial constructors will not be executed "
+        "with the current allocator");
+
     constexpr VirtualBuffer() = default;
     explicit VirtualBuffer(std::size_t count) : alloc_size{count * sizeof(T)} {
         base_ptr = reinterpret_cast<T*>(AllocateMemoryPages(alloc_size));
-- 
cgit v1.2.3