Fuchsia: Platform specific calls needed to Initialize and Cleanup VM.

runtime/vm/virtual_memory_fuchsia.cc

Index: runtime/vm/virtual_memory_fuchsia.cc
diff --git a/runtime/vm/virtual_memory_fuchsia.cc b/runtime/vm/virtual_memory_fuchsia.cc
index da32045f4c799618b4e75fe8f858cf12f28d1025..e694dca0e0e9710f064b2b499b0010bcea8b22a7 100644
--- a/runtime/vm/virtual_memory_fuchsia.cc
+++ b/runtime/vm/virtual_memory_fuchsia.cc
@@ -7,9 +7,11 @@
 
 #include "vm/virtual_memory.h"
 
+#include <magenta/syscalls.h>
 #include <unistd.h>  // NOLINT
 
 #include "platform/assert.h"
+#include "vm/memory_region.h"
 #include "vm/os.h"
 
 namespace dart {
@@ -23,13 +25,45 @@ void VirtualMemory::InitOnce() {
 
 
 VirtualMemory* VirtualMemory::ReserveInternal(intptr_t size) {
-  UNIMPLEMENTED();
-  return NULL;
+  mx_handle_t vmo = _magenta_vm_object_create(size);
+  if (vmo <= 0) {
+    return NULL;
+  }
+
+  // TODO(zra): map with PERM_NONE, when that works, and relax with
+  // Commit and Protect when they are implemented.
+  // Issue MG-161.
+  const int prot = MX_VM_FLAG_PERM_READ |
+                   MX_VM_FLAG_PERM_WRITE |
+                   MX_VM_FLAG_PERM_EXECUTE;
+  uintptr_t addr;
+  mx_status_t status = _magenta_process_vm_map(0, vmo, 0, size, &addr, prot);
+  if (status != NO_ERROR) {
+    _magenta_handle_close(vmo);
+    FATAL("VirtualMemory::ReserveInternal FAILED");
+    return NULL;
+  }
+
+  MemoryRegion region(reinterpret_cast<void*>(addr), size);
+  return new VirtualMemory(region, vmo);
 }
 
 
 VirtualMemory::~VirtualMemory() {
-  UNIMPLEMENTED();
+  if (!embedder_allocated()) {
+    // TODO(zra): Use reserved_size_.
+    // Issue MG-162.
+    mx_status_t status = _magenta_process_vm_unmap(
+        0, reinterpret_cast<uintptr_t>(address()), 0 /*reserved_size_*/);
+    if (status != NO_ERROR) {
+      FATAL("VirtualMemory::~VirtualMemory: unamp FAILED");
+    }
+
+    status = _magenta_handle_close(handle());
+    if (status != NO_ERROR) {
+      FATAL("VirtualMemory::~VirtualMemory: handle_close FAILED");
+    }
+  }
 }
 
 
@@ -40,14 +74,15 @@ bool VirtualMemory::FreeSubSegment(void* address, intptr_t size) {
 
 
 bool VirtualMemory::Commit(uword addr, intptr_t size, bool executable) {
-  UNIMPLEMENTED();
-  return false;
+  // TODO(zra): Implement when the protections for a mapping can be changed.
+  // Issue MG-133.
+  return true;
 }
 
 
 bool VirtualMemory::Protect(void* address, intptr_t size, Protection mode) {
-  UNIMPLEMENTED();
-  return false;
+  // TODO(zra): Implement when Fuchsia has an mprotect-like call.
+  return true;
 }
 
 }  // namespace dart