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

//===-- ValueObjectDynamicValue.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/ValueObjectDynamicValue.h"

// C Includes
// C++ Includes
// Other libraries and framework includes
// Project includes
#include "lldb/Core/Log.h"
#include "lldb/Core/Module.h"
#include "lldb/Core/ValueObjectList.h"
#include "lldb/Core/Value.h"
#include "lldb/Core/ValueObject.h"

#include "lldb/Symbol/ClangASTType.h"
#include "lldb/Symbol/ObjectFile.h"
#include "lldb/Symbol/SymbolContext.h"
#include "lldb/Symbol/Type.h"
#include "lldb/Symbol/Variable.h"

#include "lldb/Target/ExecutionContext.h"
#include "lldb/Target/LanguageRuntime.h"
#include "lldb/Target/Process.h"
#include "lldb/Target/RegisterContext.h"
#include "lldb/Target/Target.h"
#include "lldb/Target/Thread.h"

using namespace lldb_private;

ValueObjectDynamicValue::ValueObjectDynamicValue (ValueObject &parent, lldb::DynamicValueType use_dynamic) :
    ValueObject(parent),
    m_address (),
    m_type_sp(),
    m_use_dynamic (use_dynamic)
{
    m_last_format_mgr_dynamic = use_dynamic;
    SetName (parent.GetName());
}

ValueObjectDynamicValue::~ValueObjectDynamicValue()
{
    m_owning_valobj_sp.reset();
}

lldb::clang_type_t
ValueObjectDynamicValue::GetClangTypeImpl ()
{
    if (m_type_sp)
        return m_value.GetClangType();
    else
        return m_parent->GetClangType();
}

ConstString
ValueObjectDynamicValue::GetTypeName()
{
    const bool success = UpdateValueIfNeeded(false);
    if (success && m_type_sp)
        return ClangASTType::GetConstTypeName (GetClangAST(), GetClangType());
    else
        return m_parent->GetTypeName();
}

uint32_t
ValueObjectDynamicValue::CalculateNumChildren()
{
    const bool success = UpdateValueIfNeeded(false);
    if (success && m_type_sp)
        return ClangASTContext::GetNumChildren (GetClangAST (), GetClangType(), true);
    else
        return m_parent->GetNumChildren();
}

clang::ASTContext *
ValueObjectDynamicValue::GetClangASTImpl ()
{
    const bool success = UpdateValueIfNeeded(false);
    if (success && m_type_sp)
        return m_type_sp->GetClangAST();
    else
        return m_parent->GetClangAST ();
}

size_t
ValueObjectDynamicValue::GetByteSize()
{
    const bool success = UpdateValueIfNeeded(false);
    if (success && m_type_sp)
        return m_value.GetValueByteSize(GetClangAST(), NULL);
    else
        return m_parent->GetByteSize();
}

lldb::ValueType
ValueObjectDynamicValue::GetValueType() const
{
    return m_parent->GetValueType();
}

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

    if (!m_parent->UpdateValueIfNeeded(false))
    {
        // The dynamic value failed to get an error, pass the error along
        if (m_error.Success() && m_parent->GetError().Fail())
            m_error = m_parent->GetError();
        return false;
    }
    
    // Setting our type_sp to NULL will route everything back through our
    // parent which is equivalent to not using dynamic values.
    if (m_use_dynamic == lldb::eNoDynamicValues)
    {
        m_type_sp.reset();
        return true;
    }
    
    ExecutionContext exe_ctx (GetExecutionContextRef());
    Target *target = exe_ctx.GetTargetPtr();
    if (target)
    {
        m_data.SetByteOrder(target->GetArchitecture().GetByteOrder());
        m_data.SetAddressByteSize(target->GetArchitecture().GetAddressByteSize());
    }
    
    // First make sure our Type and/or Address haven't changed:
    Process *process = exe_ctx.GetProcessPtr();
    if (!process)
        return false;
    
    TypeAndOrName class_type_or_name;
    Address dynamic_address;
    bool found_dynamic_type = false;
    
    lldb::LanguageType known_type = m_parent->GetObjectRuntimeLanguage();
    if (known_type != lldb::eLanguageTypeUnknown && known_type != lldb::eLanguageTypeC)
    {
        LanguageRuntime *runtime = process->GetLanguageRuntime (known_type);
        if (runtime)
            found_dynamic_type = runtime->GetDynamicTypeAndAddress (*m_parent, m_use_dynamic, class_type_or_name, dynamic_address);
    }
    else
    {
        LanguageRuntime *cpp_runtime = process->GetLanguageRuntime (lldb::eLanguageTypeC_plus_plus);
        if (cpp_runtime)
            found_dynamic_type = cpp_runtime->GetDynamicTypeAndAddress (*m_parent, m_use_dynamic, class_type_or_name, dynamic_address);
        
        if (!found_dynamic_type)
        {
            LanguageRuntime *objc_runtime = process->GetLanguageRuntime (lldb::eLanguageTypeObjC);
            if (objc_runtime)
                found_dynamic_type = objc_runtime->GetDynamicTypeAndAddress (*m_parent, m_use_dynamic, class_type_or_name, dynamic_address);
        }
    }
    
    lldb::TypeSP dynamic_type_sp = class_type_or_name.GetTypeSP();
    
    // Getting the dynamic value may have run the program a bit, and so marked us as needing updating, but we really
    // don't...
    
    m_update_point.SetUpdated();
    
    // If we don't have a dynamic type, then make ourselves just a echo of our parent.
    // Or we could return false, and make ourselves an echo of our parent?
    if (!found_dynamic_type)
    {
        if (m_type_sp)
            SetValueDidChange(true);
        ClearDynamicTypeInformation();
        m_type_sp.reset();
        m_value = m_parent->GetValue();
        m_error = m_value.GetValueAsData (&exe_ctx, GetClangAST(), m_data, 0, GetModule().get());
        return m_error.Success();
    }
    
    Value old_value(m_value);

    lldb::LogSP log(lldb_private::GetLogIfAllCategoriesSet (LIBLLDB_LOG_TYPES));
    
    bool has_changed_type = false;
    
    if (!m_type_sp)
    {
        m_type_sp = dynamic_type_sp;
        has_changed_type = true;
    }
    else if (dynamic_type_sp != m_type_sp)
    {
        // We are another type, we need to tear down our children...
        m_type_sp = dynamic_type_sp;
        SetValueDidChange (true);
        has_changed_type = true;
    }
    
    if (has_changed_type)
        ClearDynamicTypeInformation ();
    
    if (!m_address.IsValid() || m_address != dynamic_address)
    {
        if (m_address.IsValid())
            SetValueDidChange (true);
            
        // We've moved, so we should be fine...
        m_address = dynamic_address;
        lldb::TargetSP target_sp (GetTargetSP());
        lldb::addr_t load_address = m_address.GetLoadAddress(target_sp.get());
        m_value.GetScalar() = load_address;
    }
    
    // The type will always be the type of the dynamic object.  If our parent's type was a pointer,
    // then our type should be a pointer to the type of the dynamic object.  If a reference, then the original type
    // should be okay...
    lldb::clang_type_t orig_type = m_type_sp->GetClangForwardType();
    lldb::clang_type_t corrected_type = orig_type;
    if (m_parent->IsPointerType())
        corrected_type = ClangASTContext::CreatePointerType (m_type_sp->GetClangAST(), orig_type);
    else if (m_parent->IsPointerOrReferenceType())
        corrected_type = ClangASTContext::CreateLValueReferenceType (m_type_sp->GetClangAST(), orig_type);
        
    m_value.SetContext (Value::eContextTypeClangType, corrected_type);
    
    // Our address is the location of the dynamic type stored in memory.  It isn't a load address,
    // because we aren't pointing to the LOCATION that stores the pointer to us, we're pointing to us...
    m_value.SetValueType(Value::eValueTypeScalar);

    if (has_changed_type && log)
        log->Printf("[%s %p] has a new dynamic type %s",
                    GetName().GetCString(),
                    this,
                    GetTypeName().GetCString());
    
    if (m_address.IsValid() && m_type_sp)
    {
        // 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, GetClangAST(), m_data, 0, GetModule().get());
        if (m_error.Success())
        {
            if (ClangASTContext::IsAggregateType (GetClangType()))
            {
                // 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 (m_value.GetValueType() != old_value.GetValueType() || m_value.GetScalar() != old_value.GetScalar());
            }

            SetValueIsValid (true);
            return true;
        }
    }
    
    // We get here if we've failed above...
    SetValueIsValid (false);
    return false;
}



bool
ValueObjectDynamicValue::IsInScope ()
{
    return m_parent->IsInScope();
}

bool
ValueObjectDynamicValue::SetValueFromCString (const char *value_str, Error& error)
{
    if (!UpdateValueIfNeeded(false))
    {
        error.SetErrorString("unable to read value");
        return false;
    }
    
    uint64_t my_value = GetValueAsUnsigned(UINT64_MAX);
    uint64_t parent_value = m_parent->GetValueAsUnsigned(UINT64_MAX);
    
    if (my_value == UINT64_MAX || parent_value == UINT64_MAX)
    {
        error.SetErrorString("unable to read value");
        return false;
    }
    
    // if we are at an offset from our parent, in order to set ourselves correctly we would need
    // to change the new value so that it refers to the correct dynamic type. we choose not to deal
    // with that - if anything more than a value overwrite is required, you should be using the
    // expression parser instead of the value editing facility
    if (my_value != parent_value)
    {
        // but NULL'ing out a value should always be allowed
        if (strcmp(value_str,"0"))
        {
            error.SetErrorString("unable to modify dynamic value, use 'expression' command");
            return false;
        }
    }
    
    bool ret_val = m_parent->SetValueFromCString(value_str,error);
    SetNeedsUpdate();
    return ret_val;
}