clang-p2996/lldb/source/Plugins/Language/ObjC/NSException.cpp

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

// C Includes
// C++ Includes
// Other libraries and framework includes
#include "clang/AST/DeclCXX.h"

// Project includes
#include "Cocoa.h"

#include "lldb/Core/DataBufferHeap.h"
#include "lldb/Core/Error.h"
#include "lldb/Core/Stream.h"
#include "lldb/Core/ValueObject.h"
#include "lldb/Core/ValueObjectConstResult.h"
#include "lldb/DataFormatters/FormattersHelpers.h"
#include "lldb/Host/Endian.h"
#include "lldb/Symbol/ClangASTContext.h"
#include "lldb/Target/ObjCLanguageRuntime.h"
#include "lldb/Target/Target.h"

#include "lldb/Utility/ProcessStructReader.h"

#include "Plugins/Language/ObjC/NSString.h"

using namespace lldb;
using namespace lldb_private;
using namespace lldb_private::formatters;

bool
lldb_private::formatters::NSException_SummaryProvider (ValueObject& valobj, Stream& stream, const TypeSummaryOptions& options)
{
    ProcessSP process_sp(valobj.GetProcessSP());
    if (!process_sp)
        return false;
    
    lldb::addr_t ptr_value = LLDB_INVALID_ADDRESS;
    
    CompilerType valobj_type(valobj.GetCompilerType());
    Flags type_flags(valobj_type.GetTypeInfo());
    if (type_flags.AllClear(eTypeHasValue))
    {
        if (valobj.IsBaseClass() && valobj.GetParent())
            ptr_value = valobj.GetParent()->GetValueAsUnsigned(LLDB_INVALID_ADDRESS);
    }
    else
        ptr_value = valobj.GetValueAsUnsigned(LLDB_INVALID_ADDRESS);
    
    if (ptr_value == LLDB_INVALID_ADDRESS)
        return false;
    size_t ptr_size = process_sp->GetAddressByteSize();
    lldb::addr_t name_location = ptr_value + 1 * ptr_size;
    lldb::addr_t reason_location = ptr_value + 2 * ptr_size;
    
    Error error;
    lldb::addr_t name = process_sp->ReadPointerFromMemory(name_location, error);
    if (error.Fail() || name == LLDB_INVALID_ADDRESS)
        return false;
    
    lldb::addr_t reason = process_sp->ReadPointerFromMemory(reason_location, error);
    if (error.Fail() || reason == LLDB_INVALID_ADDRESS)
        return false;
    
    InferiorSizedWord name_isw(name, *process_sp);
    InferiorSizedWord reason_isw(reason, *process_sp);
    
    CompilerType voidstar = process_sp->GetTarget().GetScratchClangASTContext()->GetBasicType(lldb::eBasicTypeVoid).GetPointerType();
    
    ValueObjectSP name_sp = ValueObject::CreateValueObjectFromData("name_str", name_isw.GetAsData(process_sp->GetByteOrder()), valobj.GetExecutionContextRef(), voidstar);
    ValueObjectSP reason_sp = ValueObject::CreateValueObjectFromData("reason_str", reason_isw.GetAsData(process_sp->GetByteOrder()), valobj.GetExecutionContextRef(), voidstar);
    
    if (!name_sp || !reason_sp)
        return false;
    
    StreamString name_str_summary;
    StreamString reason_str_summary;
    if (NSStringSummaryProvider(*name_sp, name_str_summary, options) &&
        NSStringSummaryProvider(*reason_sp, reason_str_summary, options) &&
        !name_str_summary.Empty() &&
        !reason_str_summary.Empty())
    {
        stream.Printf("name: %s - reason: %s", name_str_summary.GetData(), reason_str_summary.GetData());
        return true;
    }
    else
        return false;
}

class NSExceptionSyntheticFrontEnd : public SyntheticChildrenFrontEnd
{
public:
    NSExceptionSyntheticFrontEnd (lldb::ValueObjectSP valobj_sp) :
    SyntheticChildrenFrontEnd(*valobj_sp)
    {}

    ~NSExceptionSyntheticFrontEnd() override = default;
    // no need to delete m_child_ptr - it's kept alive by the cluster manager on our behalf

    size_t
    CalculateNumChildren() override
    {
        if (m_child_ptr)
            return 1;
        if (m_child_sp)
            return 1;
        return 0;
    }
    
    lldb::ValueObjectSP
    GetChildAtIndex(size_t idx) override
    {
        if (idx != 0)
            return lldb::ValueObjectSP();
        
        if (m_child_ptr)
            return m_child_ptr->GetSP();
        return m_child_sp;
    }
    
    bool
    Update() override
    {
        m_child_ptr = nullptr;
        m_child_sp.reset();
        
        ProcessSP process_sp(m_backend.GetProcessSP());
        if (!process_sp)
            return false;
        
        lldb::addr_t userinfo_location = LLDB_INVALID_ADDRESS;
        
        CompilerType valobj_type(m_backend.GetCompilerType());
        Flags type_flags(valobj_type.GetTypeInfo());
        if (type_flags.AllClear(eTypeHasValue))
        {
            if (m_backend.IsBaseClass() && m_backend.GetParent())
                userinfo_location = m_backend.GetParent()->GetValueAsUnsigned(LLDB_INVALID_ADDRESS);
        }
        else
            userinfo_location = m_backend.GetValueAsUnsigned(LLDB_INVALID_ADDRESS);
        
        if (userinfo_location == LLDB_INVALID_ADDRESS)
            return false;
        
        size_t ptr_size = process_sp->GetAddressByteSize();
        
        userinfo_location += 3 * ptr_size;
        Error error;
        lldb::addr_t userinfo = process_sp->ReadPointerFromMemory(userinfo_location, error);
        if (userinfo == LLDB_INVALID_ADDRESS || error.Fail())
            return false;
        InferiorSizedWord isw(userinfo,*process_sp);
        m_child_sp = CreateValueObjectFromData("userInfo",
                                               isw.GetAsData(process_sp->GetByteOrder()),
                                               m_backend.GetExecutionContextRef(),
                                               process_sp->GetTarget().GetScratchClangASTContext()->GetBasicType(lldb::eBasicTypeObjCID));
        return false;
    }
    
    bool
    MightHaveChildren() override
    {
        return true;
    }
    
    size_t
    GetIndexOfChildWithName(const ConstString &name) override
    {
        static ConstString g___userInfo("userInfo");
        if (name == g___userInfo)
            return 0;
        return UINT32_MAX;
    }

private:
    // the child here can be "real" (i.e. an actual child of the root) or synthetized from raw memory
    // if the former, I need to store a plain pointer to it - or else a loop of references will cause this entire hierarchy of values to leak
    // if the latter, then I need to store a SharedPointer to it - so that it only goes away when everyone else in the cluster goes away
    // oh joy!
    ValueObject* m_child_ptr;
    ValueObjectSP m_child_sp;
};

SyntheticChildrenFrontEnd*
lldb_private::formatters::NSExceptionSyntheticFrontEndCreator (CXXSyntheticChildren*, lldb::ValueObjectSP valobj_sp)
{
    lldb::ProcessSP process_sp (valobj_sp->GetProcessSP());
    if (!process_sp)
        return nullptr;
    ObjCLanguageRuntime *runtime = (ObjCLanguageRuntime*)process_sp->GetLanguageRuntime(lldb::eLanguageTypeObjC);
    if (!runtime)
        return nullptr;
    
    ObjCLanguageRuntime::ClassDescriptorSP descriptor(runtime->GetClassDescriptor(*valobj_sp.get()));
    
    if (!descriptor.get() || !descriptor->IsValid())
        return nullptr;
    
    const char* class_name = descriptor->GetClassName().GetCString();
    
    if (!class_name || !*class_name)
        return nullptr;
    
    if (!strcmp(class_name,"NSException"))
        return (new NSExceptionSyntheticFrontEnd(valobj_sp));
    else if (!strcmp(class_name,"NSCFException"))
        return (new NSExceptionSyntheticFrontEnd(valobj_sp));
    else if (!strcmp(class_name,"__NSCFException"))
        return (new NSExceptionSyntheticFrontEnd(valobj_sp));
    
    return nullptr;
}