core: Prepare various classes for memory read/write migration

Amends a few interfaces to be able to handle the migration over to the
new Memory class by passing the class by reference as a function
parameter where necessary.

Notably, within the filesystem services, this eliminates two ReadBlock()
calls by using the helper functions of HLERequestContext to do that for
us.

src/core/arm/arm_interface.cpp

@@ -13,7 +13,6 @@
 #include "core/memory.h"
 
 namespace Core {
-
 namespace {
 
 constexpr u64 ELF_DYNAMIC_TAG_NULL = 0;
@@ -156,7 +155,7 @@ std::vector<ARM_Interface::BacktraceEntry> ARM_Interface::GetBacktrace() const {
     }
 
     std::map<VAddr, std::string> modules;
-    auto& loader{System::GetInstance().GetAppLoader()};
+    auto& loader{system.GetAppLoader()};
     if (loader.ReadNSOModules(modules) != Loader::ResultStatus::Success) {
         return {};
     }

src/core/arm/arm_interface.h

@@ -17,11 +17,13 @@ enum class VMAPermission : u8;
 }
 
 namespace Core {
+class System;
 
 /// Generic ARMv8 CPU interface
 class ARM_Interface : NonCopyable {
 public:
-    virtual ~ARM_Interface() {}
+    explicit ARM_Interface(System& system_) : system{system_} {}
+    virtual ~ARM_Interface() = default;
 
     struct ThreadContext {
         std::array<u64, 31> cpu_registers;
@@ -163,6 +165,10 @@ public:
     /// fp+0 : pointer to previous frame record
     /// fp+8 : value of lr for frame
     void LogBacktrace() const;
+
+protected:
+    /// System context that this ARM interface is running under.
+    System& system;
 };
 
 } // namespace Core

src/core/arm/dynarmic/arm_dynarmic.cpp

@@ -28,6 +28,7 @@ public:
     explicit ARM_Dynarmic_Callbacks(ARM_Dynarmic& parent) : parent(parent) {}
 
     u8 MemoryRead8(u64 vaddr) override {
+        auto& s = parent.system;
         return Memory::Read8(vaddr);
     }
     u16 MemoryRead16(u64 vaddr) override {
@@ -171,9 +172,10 @@ void ARM_Dynarmic::Step() {
 
 ARM_Dynarmic::ARM_Dynarmic(System& system, ExclusiveMonitor& exclusive_monitor,
                            std::size_t core_index)
-    : cb(std::make_unique<ARM_Dynarmic_Callbacks>(*this)), inner_unicorn{system},
-      core_index{core_index}, system{system},
-      exclusive_monitor{dynamic_cast<DynarmicExclusiveMonitor&>(exclusive_monitor)} {}
+    : ARM_Interface{system},
+      cb(std::make_unique<ARM_Dynarmic_Callbacks>(*this)), inner_unicorn{system},
+      core_index{core_index}, exclusive_monitor{
+                                  dynamic_cast<DynarmicExclusiveMonitor&>(exclusive_monitor)} {}
 
 ARM_Dynarmic::~ARM_Dynarmic() = default;
 

src/core/arm/dynarmic/arm_dynarmic.h

@@ -58,7 +58,6 @@ private:
     ARM_Unicorn inner_unicorn;
 
     std::size_t core_index;
-    System& system;
     DynarmicExclusiveMonitor& exclusive_monitor;
 };
 

src/core/arm/unicorn/arm_unicorn.cpp

@@ -60,7 +60,7 @@ static bool UnmappedMemoryHook(uc_engine* uc, uc_mem_type type, u64 addr, int si
     return false;
 }
 
-ARM_Unicorn::ARM_Unicorn(System& system) : system{system} {
+ARM_Unicorn::ARM_Unicorn(System& system) : ARM_Interface{system} {
     CHECKED(uc_open(UC_ARCH_ARM64, UC_MODE_ARM, &uc));
 
     auto fpv = 3 << 20;

src/core/arm/unicorn/arm_unicorn.h

@@ -45,7 +45,6 @@ private:
     static void InterruptHook(uc_engine* uc, u32 int_no, void* user_data);
 
     uc_engine* uc{};
-    System& system;
     GDBStub::BreakpointAddress last_bkpt{};
     bool last_bkpt_hit = false;
 };