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//===-- GenericOptional.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 "Generic.h"
#include "LibCxx.h"
#include "LibStdcpp.h"
#include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
#include "lldb/DataFormatters/FormattersHelpers.h"
#include "lldb/Target/Target.h"
using namespace lldb;
using namespace lldb_private;
bool lldb_private::formatters::GenericOptionalSummaryProvider(
ValueObject &valobj, Stream &stream, const TypeSummaryOptions &options) {
stream.Printf(" Has Value=%s ",
valobj.GetNumChildren() == 0 ? "false" : "true");
return true;
}
// Synthetic Children Provider
namespace {
class GenericOptionalFrontend : public SyntheticChildrenFrontEnd {
public:
enum class StdLib {
LibCxx,
LibStdcpp,
};
GenericOptionalFrontend(ValueObject &valobj, StdLib stdlib);
size_t GetIndexOfChildWithName(ConstString name) override {
return formatters::ExtractIndexFromString(name.GetCString());
}
bool MightHaveChildren() override { return true; }
size_t CalculateNumChildren() override { return m_has_value ? 1U : 0U; }
ValueObjectSP GetChildAtIndex(size_t idx) override;
bool Update() override;
private:
bool m_has_value = false;
StdLib m_stdlib;
};
} // namespace
GenericOptionalFrontend::GenericOptionalFrontend(ValueObject &valobj,
StdLib stdlib)
: SyntheticChildrenFrontEnd(valobj), m_stdlib(stdlib) {
if (auto target_sp = m_backend.GetTargetSP()) {
Update();
}
}
bool GenericOptionalFrontend::Update() {
ValueObjectSP engaged_sp;
if (m_stdlib == StdLib::LibCxx)
engaged_sp = m_backend.GetChildMemberWithName("__engaged_");
else if (m_stdlib == StdLib::LibStdcpp)
engaged_sp = m_backend.GetChildMemberWithName("_M_payload")
->GetChildMemberWithName("_M_engaged");
if (!engaged_sp)
return false;
// _M_engaged/__engaged is a bool flag and is true if the optional contains a
// value. Converting it to unsigned gives us a size of 1 if it contains a
// value and 0 if not.
m_has_value = engaged_sp->GetValueAsUnsigned(0) != 0;
return false;
}
ValueObjectSP GenericOptionalFrontend::GetChildAtIndex(size_t _idx) {
if (!m_has_value)
return ValueObjectSP();
ValueObjectSP val_sp;
if (m_stdlib == StdLib::LibCxx)
// __val_ contains the underlying value of an optional if it has one.
// Currently because it is part of an anonymous union
// GetChildMemberWithName() does not peer through and find it unless we are
// at the parent itself. We can obtain the parent through __engaged_.
val_sp = m_backend.GetChildMemberWithName("__engaged_")
->GetParent()
->GetChildAtIndex(0)
->GetChildMemberWithName("__val_");
else if (m_stdlib == StdLib::LibStdcpp) {
val_sp = m_backend.GetChildMemberWithName("_M_payload")
->GetChildMemberWithName("_M_payload");
// In some implementations, _M_value contains the underlying value of an
// optional, and in other versions, it's in the payload member.
ValueObjectSP candidate = val_sp->GetChildMemberWithName("_M_value");
if (candidate)
val_sp = candidate;
}
if (!val_sp)
return ValueObjectSP();
CompilerType holder_type = val_sp->GetCompilerType();
if (!holder_type)
return ValueObjectSP();
return val_sp->Clone(ConstString("Value"));
}
SyntheticChildrenFrontEnd *
formatters::LibStdcppOptionalSyntheticFrontEndCreator(
CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
if (valobj_sp)
return new GenericOptionalFrontend(
*valobj_sp, GenericOptionalFrontend::StdLib::LibStdcpp);
return nullptr;
}
SyntheticChildrenFrontEnd *formatters::LibcxxOptionalSyntheticFrontEndCreator(
CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
if (valobj_sp)
return new GenericOptionalFrontend(*valobj_sp,
GenericOptionalFrontend::StdLib::LibCxx);
return nullptr;
}
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