llvm-project/lldb/source/Core/ValueObjectMemory.cpp

//===-- ValueObjectMemory.cpp ---------------------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "lldb/Core/ValueObjectMemory.h"
#include "lldb/Core/Scalar.h" // for Scalar, operator!=
#include "lldb/Core/Value.h"
#include "lldb/Core/ValueObject.h"
#include "lldb/Symbol/Type.h"
#include "lldb/Target/ExecutionContext.h"
#include "lldb/Target/Target.h"
#include "lldb/Utility/DataExtractor.h" // for DataExtractor
#include "lldb/Utility/Status.h"        // for Status
#include "lldb/lldb-types.h"            // for addr_t
#include "llvm/Support/ErrorHandling.h" // for llvm_unreachable

#include <assert.h> // for assert
#include <memory>   // for shared_ptr

namespace lldb_private {
class ExecutionContextScope;
}

using namespace lldb;
using namespace lldb_private;

ValueObjectSP ValueObjectMemory::Create(ExecutionContextScope *exe_scope,
                                        llvm::StringRef name,
                                        const Address &address,
                                        lldb::TypeSP &type_sp) {
  return (new ValueObjectMemory(exe_scope, name, address, type_sp))->GetSP();
}

ValueObjectSP ValueObjectMemory::Create(ExecutionContextScope *exe_scope,
                                        llvm::StringRef name,
                                        const Address &address,
                                        const CompilerType &ast_type) {
  return (new ValueObjectMemory(exe_scope, name, address, ast_type))->GetSP();
}

ValueObjectMemory::ValueObjectMemory(ExecutionContextScope *exe_scope,
                                     llvm::StringRef name,
                                     const Address &address,
                                     lldb::TypeSP &type_sp)
    : ValueObject(exe_scope), m_address(address), m_type_sp(type_sp),
      m_compiler_type() {
  // Do not attempt to construct one of these objects with no variable!
  assert(m_type_sp.get() != NULL);
  SetName(ConstString(name));
  m_value.SetContext(Value::eContextTypeLLDBType, m_type_sp.get());
  TargetSP target_sp(GetTargetSP());
  lldb::addr_t load_address = m_address.GetLoadAddress(target_sp.get());
  if (load_address != LLDB_INVALID_ADDRESS) {
    m_value.SetValueType(Value::eValueTypeLoadAddress);
    m_value.GetScalar() = load_address;
  } else {
    lldb::addr_t file_address = m_address.GetFileAddress();
    if (file_address != LLDB_INVALID_ADDRESS) {
      m_value.SetValueType(Value::eValueTypeFileAddress);
      m_value.GetScalar() = file_address;
    } else {
      m_value.GetScalar() = m_address.GetOffset();
      m_value.SetValueType(Value::eValueTypeScalar);
    }
  }
}

ValueObjectMemory::ValueObjectMemory(ExecutionContextScope *exe_scope,
                                     llvm::StringRef name,
                                     const Address &address,
                                     const CompilerType &ast_type)
    : ValueObject(exe_scope), m_address(address), m_type_sp(),
      m_compiler_type(ast_type) {
  // Do not attempt to construct one of these objects with no variable!
  assert(m_compiler_type.GetTypeSystem());
  assert(m_compiler_type.GetOpaqueQualType());

  TargetSP target_sp(GetTargetSP());

  SetName(ConstString(name));
  //    m_value.SetContext(Value::eContextTypeClangType,
  //    m_compiler_type.GetOpaqueQualType());
  m_value.SetCompilerType(m_compiler_type);
  lldb::addr_t load_address = m_address.GetLoadAddress(target_sp.get());
  if (load_address != LLDB_INVALID_ADDRESS) {
    m_value.SetValueType(Value::eValueTypeLoadAddress);
    m_value.GetScalar() = load_address;
  } else {
    lldb::addr_t file_address = m_address.GetFileAddress();
    if (file_address != LLDB_INVALID_ADDRESS) {
      m_value.SetValueType(Value::eValueTypeFileAddress);
      m_value.GetScalar() = file_address;
    } else {
      m_value.GetScalar() = m_address.GetOffset();
      m_value.SetValueType(Value::eValueTypeScalar);
    }
  }
}

ValueObjectMemory::~ValueObjectMemory() {}

CompilerType ValueObjectMemory::GetCompilerTypeImpl() {
  if (m_type_sp)
    return m_type_sp->GetForwardCompilerType();
  return m_compiler_type;
}

ConstString ValueObjectMemory::GetTypeName() {
  if (m_type_sp)
    return m_type_sp->GetName();
  return m_compiler_type.GetConstTypeName();
}

ConstString ValueObjectMemory::GetDisplayTypeName() {
  if (m_type_sp)
    return m_type_sp->GetForwardCompilerType().GetDisplayTypeName();
  return m_compiler_type.GetDisplayTypeName();
}

size_t ValueObjectMemory::CalculateNumChildren(uint32_t max) {
  if (m_type_sp) {
    auto child_count = m_type_sp->GetNumChildren(true);
    return child_count <= max ? child_count : max;
  }

  const bool omit_empty_base_classes = true;
  auto child_count = m_compiler_type.GetNumChildren(omit_empty_base_classes);
  return child_count <= max ? child_count : max;
}

uint64_t ValueObjectMemory::GetByteSize() {
  if (m_type_sp)
    return m_type_sp->GetByteSize();
  return m_compiler_type.GetByteSize(nullptr);
}

lldb::ValueType ValueObjectMemory::GetValueType() const {
  // RETHINK: Should this be inherited from somewhere?
  return lldb::eValueTypeVariableGlobal;
}

bool ValueObjectMemory::UpdateValue() {
  SetValueIsValid(false);
  m_error.Clear();

  ExecutionContext exe_ctx(GetExecutionContextRef());

  Target *target = exe_ctx.GetTargetPtr();
  if (target) {
    m_data.SetByteOrder(target->GetArchitecture().GetByteOrder());
    m_data.SetAddressByteSize(target->GetArchitecture().GetAddressByteSize());
  }

  Value old_value(m_value);
  if (m_address.IsValid()) {
    Value::ValueType value_type = m_value.GetValueType();

    switch (value_type) {
    default:
      llvm_unreachable("Unhandled expression result value kind...");

    case Value::eValueTypeScalar:
      // The variable value is in the Scalar value inside the m_value.
      // We can point our m_data right to it.
      m_error = m_value.GetValueAsData(&exe_ctx, m_data, 0, GetModule().get());
      break;

    case Value::eValueTypeFileAddress:
    case Value::eValueTypeLoadAddress:
    case Value::eValueTypeHostAddress:
      // The DWARF expression result was an address in the inferior
      // process. If this variable is an aggregate type, we just need
      // the address as the main value as all child variable objects
      // will rely upon this location and add an offset and then read
      // their own values as needed. If this variable is a simple
      // type, we read all data for it into m_data.
      // Make sure this type has a value before we try and read it

      // If we have a file address, convert it to a load address if we can.
      if (value_type == Value::eValueTypeFileAddress &&
          exe_ctx.GetProcessPtr()) {
        lldb::addr_t load_addr = m_address.GetLoadAddress(target);
        if (load_addr != LLDB_INVALID_ADDRESS) {
          m_value.SetValueType(Value::eValueTypeLoadAddress);
          m_value.GetScalar() = load_addr;
        }
      }

      if (!CanProvideValue()) {
        // this value object represents an aggregate type whose
        // children have values, but this object does not. So we
        // say we are changed if our location has changed.
        SetValueDidChange(value_type != old_value.GetValueType() ||
                          m_value.GetScalar() != old_value.GetScalar());
      } else {
        // Copy the Value and set the context to use our Variable
        // so it can extract read its value into m_data appropriately
        Value value(m_value);
        if (m_type_sp)
          value.SetContext(Value::eContextTypeLLDBType, m_type_sp.get());
        else {
          // value.SetContext(Value::eContextTypeClangType,
          // m_compiler_type.GetOpaqueQualType());
          value.SetCompilerType(m_compiler_type);
        }

        m_error = value.GetValueAsData(&exe_ctx, m_data, 0, GetModule().get());
      }
      break;
    }

    SetValueIsValid(m_error.Success());
  }
  return m_error.Success();
}

bool ValueObjectMemory::IsInScope() {
  // FIXME: Maybe try to read the memory address, and if that works, then
  // we are in scope?
  return true;
}

lldb::ModuleSP ValueObjectMemory::GetModule() { return m_address.GetModule(); }