1 files changed, 105 insertions, 0 deletions
diff --git a/xpcom/base/MemoryInfo.cpp b/xpcom/base/MemoryInfo.cpp
new file mode 100644
index 0000000000..6ce7f2b768
--- /dev/null
+++ b/xpcom/base/MemoryInfo.cpp
@@ -0,0 +1,105 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/MemoryInfo.h"
+
+#include "mozilla/DebugOnly.h"
+
+#include <algorithm>
+#include <windows.h>
+
+namespace mozilla {
+
+/* static */
+MemoryInfo MemoryInfo::Get(const void* aPtr, size_t aSize) {
+  MemoryInfo result;
+
+  result.mStart = uintptr_t(aPtr);
+  const char* ptr = reinterpret_cast<const char*>(aPtr);
+  const char* end = ptr + aSize;
+  DebugOnly<void*> base = nullptr;
+  while (ptr < end) {
+    MEMORY_BASIC_INFORMATION basicInfo;
+    if (!VirtualQuery(ptr, &basicInfo, sizeof(basicInfo))) {
+      break;
+    }
+
+    MOZ_ASSERT_IF(base, base == basicInfo.AllocationBase);
+    base = basicInfo.AllocationBase;
+
+    size_t regionSize =
+        std::min(size_t(basicInfo.RegionSize), size_t(end - ptr));
+
+    if (basicInfo.State == MEM_COMMIT) {
+      result.mCommitted += regionSize;
+    } else if (basicInfo.State == MEM_RESERVE) {
+      result.mReserved += regionSize;
+    } else if (basicInfo.State == MEM_FREE) {
+      result.mFree += regionSize;
+    } else {
+      MOZ_ASSERT_UNREACHABLE("Unexpected region state");
+    }
+    result.mSize += regionSize;
+    ptr += regionSize;
+
+    if (result.mType.isEmpty()) {
+      if (basicInfo.Type & MEM_IMAGE) {
+        result.mType += PageType::Image;
+      }
+      if (basicInfo.Type & MEM_MAPPED) {
+        result.mType += PageType::Mapped;
+      }
+      if (basicInfo.Type & MEM_PRIVATE) {
+        result.mType += PageType::Private;
+      }
+
+      // The first 8 bits of AllocationProtect are an enum. The remaining bits
+      // are flags.
+      switch (basicInfo.AllocationProtect & 0xff) {
+        case PAGE_EXECUTE_WRITECOPY:
+          result.mPerms += Perm::CopyOnWrite;
+          [[fallthrough]];
+        case PAGE_EXECUTE_READWRITE:
+          result.mPerms += Perm::Write;
+          [[fallthrough]];
+        case PAGE_EXECUTE_READ:
+          result.mPerms += Perm::Read;
+          [[fallthrough]];
+        case PAGE_EXECUTE:
+          result.mPerms += Perm::Execute;
+          break;
+
+        case PAGE_WRITECOPY:
+          result.mPerms += Perm::CopyOnWrite;
+          [[fallthrough]];
+        case PAGE_READWRITE:
+          result.mPerms += Perm::Write;
+          [[fallthrough]];
+        case PAGE_READONLY:
+          result.mPerms += Perm::Read;
+          break;
+
+        default:
+          break;
+      }
+
+      if (basicInfo.AllocationProtect & PAGE_GUARD) {
+        result.mPerms += Perm::Guard;
+      }
+      if (basicInfo.AllocationProtect & PAGE_NOCACHE) {
+        result.mPerms += Perm::NoCache;
+      }
+      if (basicInfo.AllocationProtect & PAGE_WRITECOMBINE) {
+        result.mPerms += Perm::WriteCombine;
+      }
+    }
+  }
+
+  result.mEnd = uintptr_t(ptr);
+  return result;
+}
+
+}  // namespace mozilla