Merge pull request #4936 from lioncash/page

page_table: Allow page tables to be moved

src/common/page_table.cpp

@@ -8,7 +8,7 @@ namespace Common {
 
 PageTable::PageTable() = default;
 
-PageTable::~PageTable() = default;
+PageTable::~PageTable() noexcept = default;
 
 void PageTable::Resize(std::size_t address_space_width_in_bits, std::size_t page_size_in_bits,
                        bool has_attribute) {

src/common/page_table.h

@@ -4,9 +4,7 @@
 
 #pragma once
 
-#include <vector>
-
-#include <boost/icl/interval_map.hpp>
+#include <tuple>
 
 #include "common/common_types.h"
 #include "common/memory_hook.h"
@@ -51,13 +49,21 @@ struct SpecialRegion {
  */
 struct PageTable {
     PageTable();
-    ~PageTable();
+    ~PageTable() noexcept;
+
+    PageTable(const PageTable&) = delete;
+    PageTable& operator=(const PageTable&) = delete;
+
+    PageTable(PageTable&&) noexcept = default;
+    PageTable& operator=(PageTable&&) noexcept = default;
 
     /**
      * Resizes the page table to be able to accomodate enough pages within
      * a given address space.
      *
      * @param address_space_width_in_bits The address size width in bits.
+     * @param page_size_in_bits           The page size in bits.
+     * @param has_attribute               Whether or not this page has any backing attributes.
      */
     void Resize(std::size_t address_space_width_in_bits, std::size_t page_size_in_bits,
                 bool has_attribute);

src/common/virtual_buffer.cpp

@@ -13,7 +13,7 @@
 
 namespace Common {
 
-void* AllocateMemoryPages(std::size_t size) {
+void* AllocateMemoryPages(std::size_t size) noexcept {
 #ifdef _WIN32
     void* base{VirtualAlloc(nullptr, size, MEM_COMMIT, PAGE_READWRITE)};
 #else
@@ -29,7 +29,7 @@ void* AllocateMemoryPages(std::size_t size) {
     return base;
 }
 
-void FreeMemoryPages(void* base, [[maybe_unused]] std::size_t size) {
+void FreeMemoryPages(void* base, [[maybe_unused]] std::size_t size) noexcept {
     if (!base) {
         return;
     }

src/common/virtual_buffer.h

@@ -4,25 +4,44 @@
 
 #pragma once
 
-#include "common/common_funcs.h"
+#include <type_traits>
+#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:
+    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));
     }
 
-    ~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);