1 files changed, 25 insertions, 1 deletions
diff --git a/source/Core/ValueObjectChild.cpp b/source/Core/ValueObjectChild.cpp
index 01f2e20dd0bc..6b4ada154d68 100644
--- a/source/Core/ValueObjectChild.cpp
+++ b/source/Core/ValueObjectChild.cpp
@@ -175,6 +175,30 @@ bool ValueObjectChild::UpdateValue() {
             // Set this object's scalar value to the address of its value by
             // adding its byte offset to the parent address
             m_value.GetScalar() += GetByteOffset();
+
+            // If a bitfield doesn't fit into the child_byte_size'd
+            // window at child_byte_offset, move the window forward
+            // until it fits.  The problem here is that Value has no
+            // notion of bitfields and thus the Value's DataExtractor
+            // is sized like the bitfields CompilerType; a sequence of
+            // bitfields, however, can be larger than their underlying
+            // type.
+            if (m_bitfield_bit_offset) {
+              const bool thread_and_frame_only_if_stopped = true;
+              ExecutionContext exe_ctx(GetExecutionContextRef().Lock(
+                  thread_and_frame_only_if_stopped));
+              if (auto type_bit_size = GetCompilerType().GetBitSize(
+                      exe_ctx.GetBestExecutionContextScope())) {
+                uint64_t bitfield_end =
+                    m_bitfield_bit_size + m_bitfield_bit_offset;
+                if (bitfield_end > *type_bit_size) {
+                  uint64_t overhang_bytes =
+                      (bitfield_end - *type_bit_size + 7) / 8;
+                  m_value.GetScalar() += overhang_bytes;
+                  m_bitfield_bit_offset -= overhang_bytes * 8;
+                }
+              }
+            }
           }
         } break;
 
@@ -203,7 +227,7 @@ bool ValueObjectChild::UpdateValue() {
         if (GetCompilerType().GetTypeInfo() & lldb::eTypeHasValue) {
           Value &value = is_instance_ptr_base ? m_parent->GetValue() : m_value;
           m_error =
-              value.GetValueAsData(&exe_ctx, m_data, 0, GetModule().get());
+              value.GetValueAsData(&exe_ctx, m_data, GetModule().get());
         } else {
           m_error.Clear(); // No value so nothing to read...
         }