1 files changed, 252 insertions, 0 deletions
diff --git a/lldb/source/Core/ValueObjectChild.cpp b/lldb/source/Core/ValueObjectChild.cpp
new file mode 100644
index 0000000000000..6b4ada154d68b
--- /dev/null
+++ b/lldb/source/Core/ValueObjectChild.cpp
@@ -0,0 +1,252 @@
+//===-- ValueObjectChild.cpp ------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "lldb/Core/ValueObjectChild.h"
+
+#include "lldb/Core/Value.h"
+#include "lldb/Symbol/CompilerType.h"
+#include "lldb/Target/ExecutionContext.h"
+#include "lldb/Target/Process.h"
+#include "lldb/Utility/Flags.h"
+#include "lldb/Utility/Scalar.h"
+#include "lldb/Utility/Status.h"
+#include "lldb/lldb-forward.h"
+
+#include <functional>
+#include <memory>
+#include <vector>
+
+#include <stdio.h>
+#include <string.h>
+
+using namespace lldb_private;
+
+ValueObjectChild::ValueObjectChild(
+    ValueObject &parent, const CompilerType &compiler_type,
+    ConstString name, uint64_t byte_size, int32_t byte_offset,
+    uint32_t bitfield_bit_size, uint32_t bitfield_bit_offset,
+    bool is_base_class, bool is_deref_of_parent,
+    AddressType child_ptr_or_ref_addr_type, uint64_t language_flags)
+    : ValueObject(parent), m_compiler_type(compiler_type),
+      m_byte_size(byte_size), m_byte_offset(byte_offset),
+      m_bitfield_bit_size(bitfield_bit_size),
+      m_bitfield_bit_offset(bitfield_bit_offset),
+      m_is_base_class(is_base_class), m_is_deref_of_parent(is_deref_of_parent),
+      m_can_update_with_invalid_exe_ctx() {
+  m_name = name;
+  SetAddressTypeOfChildren(child_ptr_or_ref_addr_type);
+  SetLanguageFlags(language_flags);
+}
+
+ValueObjectChild::~ValueObjectChild() {}
+
+lldb::ValueType ValueObjectChild::GetValueType() const {
+  return m_parent->GetValueType();
+}
+
+size_t ValueObjectChild::CalculateNumChildren(uint32_t max) {
+  ExecutionContext exe_ctx(GetExecutionContextRef());
+  auto children_count = GetCompilerType().GetNumChildren(true, &exe_ctx);
+  return children_count <= max ? children_count : max;
+}
+
+static void AdjustForBitfieldness(ConstString &name,
+                                  uint8_t bitfield_bit_size) {
+  if (name && bitfield_bit_size) {
+    const char *compiler_type_name = name.AsCString();
+    if (compiler_type_name) {
+      std::vector<char> bitfield_type_name(strlen(compiler_type_name) + 32, 0);
+      ::snprintf(&bitfield_type_name.front(), bitfield_type_name.size(),
+                 "%s:%u", compiler_type_name, bitfield_bit_size);
+      name.SetCString(&bitfield_type_name.front());
+    }
+  }
+}
+
+ConstString ValueObjectChild::GetTypeName() {
+  if (m_type_name.IsEmpty()) {
+    m_type_name = GetCompilerType().GetConstTypeName();
+    AdjustForBitfieldness(m_type_name, m_bitfield_bit_size);
+  }
+  return m_type_name;
+}
+
+ConstString ValueObjectChild::GetQualifiedTypeName() {
+  ConstString qualified_name = GetCompilerType().GetConstTypeName();
+  AdjustForBitfieldness(qualified_name, m_bitfield_bit_size);
+  return qualified_name;
+}
+
+ConstString ValueObjectChild::GetDisplayTypeName() {
+  ConstString display_name = GetCompilerType().GetDisplayTypeName();
+  AdjustForBitfieldness(display_name, m_bitfield_bit_size);
+  return display_name;
+}
+
+LazyBool ValueObjectChild::CanUpdateWithInvalidExecutionContext() {
+  if (m_can_update_with_invalid_exe_ctx.hasValue())
+    return m_can_update_with_invalid_exe_ctx.getValue();
+  if (m_parent) {
+    ValueObject *opinionated_parent =
+        m_parent->FollowParentChain([](ValueObject *valobj) -> bool {
+          return (valobj->CanUpdateWithInvalidExecutionContext() ==
+                  eLazyBoolCalculate);
+        });
+    if (opinionated_parent)
+      return (m_can_update_with_invalid_exe_ctx =
+                  opinionated_parent->CanUpdateWithInvalidExecutionContext())
+          .getValue();
+  }
+  return (m_can_update_with_invalid_exe_ctx =
+              this->ValueObject::CanUpdateWithInvalidExecutionContext())
+      .getValue();
+}
+
+bool ValueObjectChild::UpdateValue() {
+  m_error.Clear();
+  SetValueIsValid(false);
+  ValueObject *parent = m_parent;
+  if (parent) {
+    if (parent->UpdateValueIfNeeded(false)) {
+      m_value.SetCompilerType(GetCompilerType());
+
+      CompilerType parent_type(parent->GetCompilerType());
+      // Copy the parent scalar value and the scalar value type
+      m_value.GetScalar() = parent->GetValue().GetScalar();
+      Value::ValueType value_type = parent->GetValue().GetValueType();
+      m_value.SetValueType(value_type);
+
+      Flags parent_type_flags(parent_type.GetTypeInfo());
+      const bool is_instance_ptr_base =
+          ((m_is_base_class) &&
+           (parent_type_flags.AnySet(lldb::eTypeInstanceIsPointer)));
+
+      if (parent->GetCompilerType().ShouldTreatScalarValueAsAddress()) {
+        lldb::addr_t addr = parent->GetPointerValue();
+        m_value.GetScalar() = addr;
+
+        if (addr == LLDB_INVALID_ADDRESS) {
+          m_error.SetErrorString("parent address is invalid.");
+        } else if (addr == 0) {
+          m_error.SetErrorString("parent is NULL");
+        } else {
+          m_value.GetScalar() += m_byte_offset;
+          AddressType addr_type = parent->GetAddressTypeOfChildren();
+
+          switch (addr_type) {
+          case eAddressTypeFile: {
+            lldb::ProcessSP process_sp(GetProcessSP());
+            if (process_sp && process_sp->IsAlive())
+              m_value.SetValueType(Value::eValueTypeLoadAddress);
+            else
+              m_value.SetValueType(Value::eValueTypeFileAddress);
+          } break;
+          case eAddressTypeLoad:
+            m_value.SetValueType(is_instance_ptr_base
+                                     ? Value::eValueTypeScalar
+                                     : Value::eValueTypeLoadAddress);
+            break;
+          case eAddressTypeHost:
+            m_value.SetValueType(Value::eValueTypeHostAddress);
+            break;
+          case eAddressTypeInvalid:
+            // TODO: does this make sense?
+            m_value.SetValueType(Value::eValueTypeScalar);
+            break;
+          }
+        }
+      } else {
+        switch (value_type) {
+        case Value::eValueTypeLoadAddress:
+        case Value::eValueTypeFileAddress:
+        case Value::eValueTypeHostAddress: {
+          lldb::addr_t addr =
+              m_value.GetScalar().ULongLong(LLDB_INVALID_ADDRESS);
+          if (addr == LLDB_INVALID_ADDRESS) {
+            m_error.SetErrorString("parent address is invalid.");
+          } else if (addr == 0) {
+            m_error.SetErrorString("parent is NULL");
+          } else {
+            // 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;
+
+        case Value::eValueTypeScalar:
+          // try to extract the child value from the parent's scalar value
+          {
+            Scalar scalar(m_value.GetScalar());
+            if (m_bitfield_bit_size)
+              scalar.ExtractBitfield(m_bitfield_bit_size,
+                                     m_bitfield_bit_offset);
+            else
+              scalar.ExtractBitfield(8 * m_byte_size, 8 * m_byte_offset);
+            m_value.GetScalar() = scalar;
+          }
+          break;
+        default:
+          m_error.SetErrorString("parent has invalid value.");
+          break;
+        }
+      }
+
+      if (m_error.Success()) {
+        const bool thread_and_frame_only_if_stopped = true;
+        ExecutionContext exe_ctx(
+            GetExecutionContextRef().Lock(thread_and_frame_only_if_stopped));
+        if (GetCompilerType().GetTypeInfo() & lldb::eTypeHasValue) {
+          Value &value = is_instance_ptr_base ? m_parent->GetValue() : m_value;
+          m_error =
+              value.GetValueAsData(&exe_ctx, m_data, GetModule().get());
+        } else {
+          m_error.Clear(); // No value so nothing to read...
+        }
+      }
+
+    } else {
+      m_error.SetErrorStringWithFormat("parent failed to evaluate: %s",
+                                       parent->GetError().AsCString());
+    }
+  } else {
+    m_error.SetErrorString("ValueObjectChild has a NULL parent ValueObject.");
+  }
+
+  return m_error.Success();
+}
+
+bool ValueObjectChild::IsInScope() {
+  ValueObject *root(GetRoot());
+  if (root)
+    return root->IsInScope();
+  return false;
+}