MemArena: Use mach vm functions on iOS

Source/Core/Common/MemArena.cpp

@@ -60,6 +60,13 @@ void MemArena::GrabSHMSegment(size_t size)
   const std::string name = "dolphin-emu." + std::to_string(GetCurrentProcessId());
   hMemoryMapping = CreateFileMapping(INVALID_HANDLE_VALUE, nullptr, PAGE_READWRITE, 0,
                                      static_cast<DWORD>(size), UTF8ToTStr(name).c_str());
+#elif defined(IPHONEOS)
+  vm_size = size;
+  kern_return_t retval = vm_allocate(mach_task_self(), &vm_mem, size, VM_FLAGS_ANYWHERE);
+  if (retval != KERN_SUCCESS)
+  {
+    PanicAlert("Failed to grab a block of virtual memory: 0x%x", retval);
+  }
 #elif defined(ANDROID)
   fd = AshmemCreateFileMapping(("dolphin-emu." + std::to_string(getpid())).c_str(), size);
   if (fd < 0)
@@ -86,6 +93,10 @@ void MemArena::ReleaseSHMSegment()
 #ifdef _WIN32
   CloseHandle(hMemoryMapping);
   hMemoryMapping = 0;
+#elif defined(IPHONEOS)
+  vm_deallocate(mach_task_self(), vm_mem, vm_size);
+  vm_size = 0;
+  vm_mem = 0;
 #else
   close(fd);
 #endif
@@ -95,6 +106,25 @@ void* MemArena::CreateView(s64 offset, size_t size, void* base)
 {
 #ifdef _WIN32
   return MapViewOfFileEx(hMemoryMapping, FILE_MAP_ALL_ACCESS, 0, (DWORD)((u64)offset), size, base);
+#elif defined(IPHONEOS)
+    vm_address_t target = (vm_address_t)base;
+    uint64_t mask = 0;
+    bool anywhere = false;
+    vm_address_t source = vm_mem + offset;
+    vm_prot_t cur_protection = 0;
+    vm_prot_t max_protection = 0;
+
+    kern_return_t retval = vm_remap(mach_task_self(), &target, size, mask, anywhere,
+                                    mach_task_self(), source, false,
+                                    &cur_protection, &max_protection, VM_INHERIT_DEFAULT);
+    if (retval != KERN_SUCCESS)
+    {
+      PanicAlert("vm_remap failed (0x%x) - could not remap from %llx (offset %llx) of size %llx to %p",
+                (int)retval, (uint64_t)source, (uint64_t)offset, (uint64_t)size, base);
+      return nullptr;
+    }
+
+    return (void *)target;
 #else
   void* retval = mmap(base, size, PROT_READ | PROT_WRITE,
                       MAP_SHARED | ((base == nullptr) ? 0 : MAP_FIXED), fd, offset);
@@ -115,6 +145,8 @@ void MemArena::ReleaseView(void* view, size_t size)
 {
 #ifdef _WIN32
   UnmapViewOfFile(view);
+#elif defined(IPHONEOS)
+  vm_deallocate(mach_task_self(), (vm_address_t)view, size);
 #else
   munmap(view, size);
 #endif
@@ -137,6 +169,18 @@ u8* MemArena::FindMemoryBase()
   }
   VirtualFree(base, 0, MEM_RELEASE);
   return base;
+#elif defined(IPHONEOS)
+  vm_address_t addr = 0;
+  kern_return_t retval = vm_allocate(mach_task_self(), &addr, memory_size, VM_FLAGS_ANYWHERE);
+  if (retval != KERN_SUCCESS)
+  {
+    PanicAlert("Failed to map enough memory space: 0x%x", retval);
+    exit(0);
+  }
+
+  // Don't need the memory now, was just probing.
+  vm_deallocate(mach_task_self(), addr, memory_size);
+  return (u8*)addr;
 #else
 #ifdef ANDROID
   // Android 4.3 changed how mmap works.

Source/Core/Common/MemArena.h

@@ -8,6 +8,8 @@
 
 #ifdef _WIN32
 #include <windows.h>
+#elif defined(IPHONEOS)
+#include <mach/mach.h>
 #endif
 
 #include "Common/CommonTypes.h"
@@ -32,6 +34,9 @@ class MemArena
 private:
 #ifdef _WIN32
   HANDLE hMemoryMapping;
+#elif defined(IPHONEOS)
+  vm_size_t vm_size;
+  vm_address_t vm_mem;
 #else
   int fd;
 #endif