Make syzyasan_rtl compile in 64 bit

syzygy/agent/asan/shadow.cc

Index: syzygy/agent/asan/shadow.cc
diff --git a/syzygy/agent/asan/shadow.cc b/syzygy/agent/asan/shadow.cc
index de8452cc53c35745a564d6997cd3227c68fe609f..0f7fe599370aac2ab9f4d3537e42290fe5e9dfe4 100644
--- a/syzygy/agent/asan/shadow.cc
+++ b/syzygy/agent/asan/shadow.cc
@@ -33,7 +33,7 @@ base::Lock shadow_instance_lock;
 // The pointer for the exception handler to know what shadow object is
 // currently used. Under shadow_instance_lock.
 // TODO(loskutov): eliminate this by enforcing Shadow to be a singleton.
-const Shadow* shadow_instance;
+const Shadow* shadow_instance = nullptr;
 
 // The exception handler, intended to map the pages for shadow and page_bits
 // on demand. When a page fault happens, the operating systems calls
@@ -41,6 +41,7 @@ const Shadow* shadow_instance;
 // commited seamlessly for the caller, and then execution continues.
 // Otherwise, the OS keeps searching for an appropriate handler.
 LONG NTAPI ShadowExceptionHandler(PEXCEPTION_POINTERS exception_pointers) {
+  DCHECK_NE(static_cast<const Shadow*>(nullptr), shadow_instance);
   // Only handle access violations.
   if (exception_pointers->ExceptionRecord->ExceptionCode !=
       EXCEPTION_ACCESS_VIOLATION) {
@@ -92,6 +93,16 @@ inline void AddressToPageMask(const void* address,
   *mask = 1 << (i % 8);
 }
 
+// Check if |addr| is in a memory region that has been committed.
+bool AddressIsInCommittedMemory(const void* addr) {
+  MEMORY_BASIC_INFORMATION memory_info = {};
+  SIZE_T mem_status = ::VirtualQuery(addr, &memory_info, sizeof(memory_info));
+  DCHECK_GT(mem_status, 0u);
+  if (memory_info.State != MEM_COMMIT)
+    return false;
+  return true;
+}
+
 }  // namespace
 
 Shadow::Shadow() : own_memory_(false), shadow_(nullptr), length_(0) {
@@ -215,7 +226,7 @@ bool Shadow::IsClean() const {
       auto ret = ::VirtualQuery(cursor, &info, sizeof(info));
       DCHECK_GT(ret, 0u);
       next_cursor = static_cast<uint8_t*>(info.BaseAddress) + info.RegionSize;
-      if (info.Type == MEM_COMMIT)
+      if (info.State == MEM_COMMIT)
         break;
       cursor = next_cursor;
     }
@@ -884,9 +895,13 @@ bool Shadow::ScanLeftForBracketingBlockStart(
 
   size_t left = cursor;
   int nesting_depth = static_cast<int>(initial_nesting_depth);
+  if (!AddressIsInCommittedMemory((&shadow_[left])))
+    return false;
   if (ShadowMarkerHelper::IsBlockEnd(shadow_[left]))
     --nesting_depth;
   while (true) {
+    if (!AddressIsInCommittedMemory((&shadow_[left])))
+      return false;
     if (ShadowMarkerHelper::IsBlockStart(shadow_[left])) {
       if (nesting_depth == 0) {
         *location = left;
@@ -1049,6 +1064,9 @@ bool Shadow::BlockInfoFromShadowImpl(
   size_t left = reinterpret_cast<uintptr_t>(addr) / kShadowRatio;
   size_t right = left;
 
+  if (!AddressIsInCommittedMemory(&shadow_[left]))
+    return false;
+
   if (!ScanLeftForBracketingBlockStart(initial_nesting_depth, left, &left))
     return false;
   if (!ScanRightForBracketingBlockEnd(initial_nesting_depth, right, &right))