0e4c482124
My apologies for the large patch. With the exception of ConstString.h itself it was entirely produced by sed. ConstString has exactly one const char * data member, so passing a ConstString by reference is not any more efficient than copying it by value. In both cases a single pointer is passed. But passing it by value makes it harder to accidentally return the address of a local object. (This fixes rdar://problem/48640859 for the Apple folks) Differential Revision: https://reviews.llvm.org/D59030 llvm-svn: 355553
85 lines
2.5 KiB
C++
85 lines
2.5 KiB
C++
//===-- LibCxxOptional.cpp --------------------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "LibCxx.h"
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#include "lldb/DataFormatters/FormattersHelpers.h"
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using namespace lldb;
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using namespace lldb_private;
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namespace {
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class OptionalFrontEnd : public SyntheticChildrenFrontEnd {
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public:
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OptionalFrontEnd(ValueObject &valobj) : SyntheticChildrenFrontEnd(valobj) {
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Update();
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}
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size_t GetIndexOfChildWithName(ConstString name) override {
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return formatters::ExtractIndexFromString(name.GetCString());
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}
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bool MightHaveChildren() override { return true; }
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bool Update() override;
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size_t CalculateNumChildren() override { return m_size; }
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ValueObjectSP GetChildAtIndex(size_t idx) override;
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private:
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size_t m_size = 0;
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ValueObjectSP m_base_sp;
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};
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} // namespace
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bool OptionalFrontEnd::Update() {
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ValueObjectSP engaged_sp(
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m_backend.GetChildMemberWithName(ConstString("__engaged_"), true));
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if (!engaged_sp)
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return false;
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// __engaged_ is a bool flag and is true if the optional contains a value.
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// Converting it to unsigned gives us a size of 1 if it contains a value
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// and 0 if not.
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m_size = engaged_sp->GetValueAsUnsigned(0);
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return false;
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}
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ValueObjectSP OptionalFrontEnd::GetChildAtIndex(size_t idx) {
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if (idx >= m_size)
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return ValueObjectSP();
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// __val_ contains the underlying value of an optional if it has one.
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// Currently because it is part of an anonymous union GetChildMemberWithName()
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// does not peer through and find it unless we are at the parent itself.
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// We can obtain the parent through __engaged_.
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ValueObjectSP val_sp(
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m_backend.GetChildMemberWithName(ConstString("__engaged_"), true)
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->GetParent()
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->GetChildAtIndex(0, true)
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->GetChildMemberWithName(ConstString("__val_"), true));
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if (!val_sp)
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return ValueObjectSP();
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CompilerType holder_type = val_sp->GetCompilerType();
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if (!holder_type)
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return ValueObjectSP();
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return val_sp->Clone(ConstString(llvm::formatv("Value").str()));
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}
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SyntheticChildrenFrontEnd *
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formatters::LibcxxOptionalFrontEndCreator(CXXSyntheticChildren *,
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lldb::ValueObjectSP valobj_sp) {
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if (valobj_sp)
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return new OptionalFrontEnd(*valobj_sp);
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return nullptr;
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}
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