[lldb] [llvm] [Obj2Yaml] Add support for minidump generation with 64b memory ranges. (PR #101272)

[Pavel Labath via llvm-commits]

================
@@ -132,6 +140,92 @@ class MinidumpFile : public Binary {
     size_t Stride;
   };
 
+  /// Class the provides an iterator over the memory64 memory ranges. Only the
+  /// the first descriptor is validated as readable beforehand.
+  class Memory64Iterator {
+  public:
+    static Memory64Iterator
+    begin(ArrayRef<uint8_t> Storage,
+          ArrayRef<minidump::MemoryDescriptor_64> Descriptors) {
+      return Memory64Iterator(Storage, Descriptors);
+    }
+
+    static Memory64Iterator end() { return Memory64Iterator(); }
+
+    bool operator==(const Memory64Iterator &R) const {
+      return IsEnd == R.IsEnd;
+    }
+
+    bool operator!=(const Memory64Iterator &R) const { return !(*this == R); }
+
+    const std::pair<minidump::MemoryDescriptor_64, ArrayRef<uint8_t>> &
+    operator*() {
+      return Current;
+    }
+
+    const std::pair<minidump::MemoryDescriptor_64, ArrayRef<uint8_t>> *
+    operator->() {
+      return &Current;
+    }
+
+    Error inc() {
+      if (Storage.size() == 0 || Descriptors.size() == 0) {
+        IsEnd = true;
+        return Error::success();
+      }
+
+      // Drop front gives us an array ref, so we need to call .front() as well.
+      const minidump::MemoryDescriptor_64 &Descriptor = Descriptors.front();
+      if (Descriptor.DataSize > Storage.size()) {
+        IsEnd = true;
+        return make_error<GenericBinaryError>(
+            "Memory64 Descriptor exceeds end of file.",
+            object_error::unexpected_eof);
+      }
+
+      ArrayRef<uint8_t> Content = Storage.take_front(Descriptor.DataSize);
+      Current = std::make_pair(Descriptor, Content);
+
+      Storage = Storage.drop_front(Descriptor.DataSize);
+      Descriptors = Descriptors.drop_front();
+
+      if (Descriptors.empty())
+        IsEnd = true;
----------------
labath wrote:

This doesn't look correct. Since you're holding the "current" object in a separate member, the emptyness of this does not indicate that you've reached the end (well, you sort of did, but the end iterator should point **past** the end of the array). I would expect that this should be caught the next time someone calls this function (attempts to increment the iterator).

https://github.com/llvm/llvm-project/pull/101272