================ @@ -0,0 +1,325 @@ +//===-- ValueObjectVTable.cpp ---------------------------------------------===// +// +// 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/ValueObjectVTable.h" +#include "lldb/Core/Module.h" +#include "lldb/Core/ValueObjectChild.h" +#include "lldb/Symbol/Function.h" +#include "lldb/lldb-defines.h" +#include "lldb/lldb-enumerations.h" +#include "lldb/lldb-forward.h" +#include "lldb/lldb-private-enumerations.h" +#include "clang/Tooling/Transformer/RangeSelector.h" +#include "llvm/Support/MathExtras.h" +#include <cstdint> + +using namespace lldb; +using namespace lldb_private; + +class ValueObjectVTableChild : public ValueObject { +public: + ValueObjectVTableChild(ValueObject &parent, uint32_t func_idx, + uint64_t addr_size) + : ValueObject(parent), m_func_idx(func_idx), m_addr_size(addr_size) { + SetFormat(eFormatPointer); + SetName(ConstString(llvm::formatv("[{0}]", func_idx).str())); + } + + ~ValueObjectVTableChild() override = default; + + std::optional<uint64_t> GetByteSize() override { return m_addr_size; }; + + size_t CalculateNumChildren(uint32_t max) override { return 0; }; + + ValueType GetValueType() const override { return eValueTypeVTableEntry; }; + + bool IsInScope() override { + ValueObject *parent = GetParent(); + if (parent) + return parent->IsInScope(); + return false; + }; + +protected: + bool UpdateValue() override { + SetValueIsValid(false); + m_value.Clear(); + ValueObject *parent = GetParent(); + if (!parent) { + m_error.SetErrorString("no parent object"); + return false; + } + + addr_t parent_addr = parent->GetValueAsUnsigned(LLDB_INVALID_ADDRESS); + if (parent_addr == LLDB_INVALID_ADDRESS) { + m_error.SetErrorString("parent has invalid address"); + return false; + } + + ProcessSP process_sp = GetProcessSP(); + if (!process_sp) { + m_error.SetErrorString("no process"); + return false; + } + + TargetSP target_sp = GetTargetSP(); + if (!target_sp) { + m_error.SetErrorString("no target"); + return false; + } + + // Each `vtable_entry_addr` points to the function pointer. + addr_t vtable_entry_addr = parent_addr + m_func_idx * m_addr_size; + addr_t vfunc_ptr = + process_sp->ReadPointerFromMemory(vtable_entry_addr, m_error); + if (m_error.Fail()) { + m_error.SetErrorStringWithFormat( + "failed to read virtual function entry 0x%16.16" PRIx64, + vtable_entry_addr); + return false; + } + + Address resolved_vfunc_ptr_address; + target_sp->ResolveLoadAddress(vfunc_ptr, resolved_vfunc_ptr_address); + if (!resolved_vfunc_ptr_address.IsValid()) { + m_error.SetErrorStringWithFormat( + "unable to resolve func ptr address: 0x%16.16" PRIx64, vfunc_ptr); + return false; + } + + // Set our value to be the load address of the function pointer in memory + // and our type to be the function pointer type. + m_value.SetValueType(Value::ValueType::LoadAddress); + m_value.GetScalar() = vtable_entry_addr; + + // See if our resolved address points to a function in the debug info. If + // it does, then we can report the type as a function prototype for this + // function. + Function *function = + resolved_vfunc_ptr_address.CalculateSymbolContextFunction(); + if (function) { + m_value.SetCompilerType(function->GetCompilerType()); + } else { + // Set our value's compiler type to a generic function protoype so that + // it displays as a hex function pointer for the value and the summary + // will display the address description. + auto type_system_or_err = ---------------- bulbazord wrote:
One interesting use case this could work for is swift's value witness tables. Although not the exact same as a vtable, it is a similar concept that I think is worth making this more generic for. https://github.com/llvm/llvm-project/pull/67599 _______________________________________________ lldb-commits mailing list lldb-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-commits
