1 //===-- GenericBitset.cpp //-----------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "LibCxx.h" 10 #include "LibStdcpp.h" 11 #include "Plugins/TypeSystem/Clang/TypeSystemClang.h" 12 #include "lldb/DataFormatters/FormattersHelpers.h" 13 #include "lldb/Target/Target.h" 14 15 using namespace lldb; 16 using namespace lldb_private; 17 18 namespace { 19 20 /// This class can be used for handling bitsets from both libcxx and libstdcpp. 21 class GenericBitsetFrontEnd : public SyntheticChildrenFrontEnd { 22 public: 23 enum class StdLib { 24 LibCxx, 25 LibStdcpp, 26 }; 27 28 GenericBitsetFrontEnd(ValueObject &valobj, StdLib stdlib); 29 30 size_t GetIndexOfChildWithName(ConstString name) override { 31 return formatters::ExtractIndexFromString(name.GetCString()); 32 } 33 34 bool MightHaveChildren() override { return true; } 35 bool Update() override; 36 size_t CalculateNumChildren() override { return m_elements.size(); } 37 ValueObjectSP GetChildAtIndex(size_t idx) override; 38 39 private: 40 ConstString GetDataContainerMemberName(); 41 42 // The lifetime of a ValueObject and all its derivative ValueObjects 43 // (children, clones, etc.) is managed by a ClusterManager. These 44 // objects are only destroyed when every shared pointer to any of them 45 // is destroyed, so we must not store a shared pointer to any ValueObject 46 // derived from our backend ValueObject (since we're in the same cluster). 47 // Value objects created from raw data (i.e. in a different cluster) must 48 // be referenced via shared pointer to keep them alive, however. 49 std::vector<ValueObjectSP> m_elements; 50 ValueObject *m_first = nullptr; 51 CompilerType m_bool_type; 52 ByteOrder m_byte_order = eByteOrderInvalid; 53 uint8_t m_byte_size = 0; 54 StdLib m_stdlib; 55 }; 56 } // namespace 57 58 GenericBitsetFrontEnd::GenericBitsetFrontEnd(ValueObject &valobj, StdLib stdlib) 59 : SyntheticChildrenFrontEnd(valobj), m_stdlib(stdlib) { 60 m_bool_type = valobj.GetCompilerType().GetBasicTypeFromAST(eBasicTypeBool); 61 if (auto target_sp = m_backend.GetTargetSP()) { 62 m_byte_order = target_sp->GetArchitecture().GetByteOrder(); 63 m_byte_size = target_sp->GetArchitecture().GetAddressByteSize(); 64 Update(); 65 } 66 } 67 68 ConstString GenericBitsetFrontEnd::GetDataContainerMemberName() { 69 switch (m_stdlib) { 70 case StdLib::LibCxx: 71 return ConstString("__first_"); 72 case StdLib::LibStdcpp: 73 return ConstString("_M_w"); 74 } 75 } 76 77 bool GenericBitsetFrontEnd::Update() { 78 m_elements.clear(); 79 m_first = nullptr; 80 81 TargetSP target_sp = m_backend.GetTargetSP(); 82 if (!target_sp) 83 return false; 84 85 size_t size = 0; 86 87 if (auto arg = m_backend.GetCompilerType().GetIntegralTemplateArgument(0)) 88 size = arg->value.getLimitedValue(); 89 90 m_elements.assign(size, ValueObjectSP()); 91 m_first = m_backend.GetChildMemberWithName(GetDataContainerMemberName(), true) 92 .get(); 93 return false; 94 } 95 96 ValueObjectSP GenericBitsetFrontEnd::GetChildAtIndex(size_t idx) { 97 if (idx >= m_elements.size() || !m_first) 98 return ValueObjectSP(); 99 100 if (m_elements[idx]) 101 return m_elements[idx]; 102 103 ExecutionContext ctx = m_backend.GetExecutionContextRef().Lock(false); 104 CompilerType type; 105 ValueObjectSP chunk; 106 // For small bitsets __first_ is not an array, but a plain size_t. 107 if (m_first->GetCompilerType().IsArrayType(&type)) { 108 llvm::Optional<uint64_t> bit_size = 109 type.GetBitSize(ctx.GetBestExecutionContextScope()); 110 if (!bit_size || *bit_size == 0) 111 return {}; 112 chunk = m_first->GetChildAtIndex(idx / *bit_size, true); 113 } else { 114 type = m_first->GetCompilerType(); 115 chunk = m_first->GetSP(); 116 } 117 if (!type || !chunk) 118 return {}; 119 120 llvm::Optional<uint64_t> bit_size = 121 type.GetBitSize(ctx.GetBestExecutionContextScope()); 122 if (!bit_size || *bit_size == 0) 123 return {}; 124 size_t chunk_idx = idx % *bit_size; 125 uint8_t value = !!(chunk->GetValueAsUnsigned(0) & (uint64_t(1) << chunk_idx)); 126 DataExtractor data(&value, sizeof(value), m_byte_order, m_byte_size); 127 128 m_elements[idx] = CreateValueObjectFromData(llvm::formatv("[{0}]", idx).str(), 129 data, ctx, m_bool_type); 130 131 return m_elements[idx]; 132 } 133 134 SyntheticChildrenFrontEnd *formatters::LibStdcppBitsetSyntheticFrontEndCreator( 135 CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) { 136 if (valobj_sp) 137 return new GenericBitsetFrontEnd(*valobj_sp, 138 GenericBitsetFrontEnd::StdLib::LibStdcpp); 139 return nullptr; 140 } 141 142 SyntheticChildrenFrontEnd *formatters::LibcxxBitsetSyntheticFrontEndCreator( 143 CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) { 144 if (valobj_sp) 145 return new GenericBitsetFrontEnd(*valobj_sp, 146 GenericBitsetFrontEnd::StdLib::LibCxx); 147 return nullptr; 148 } 149