1 //===-- LibCxxSliceArray.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
11 #include "lldb/Core/ValueObject.h"
12 #include "lldb/DataFormatters/FormattersHelpers.h"
13 #include <optional>
14
15 using namespace lldb;
16 using namespace lldb_private;
17 using namespace lldb_private::formatters;
18
19 namespace lldb_private {
20 namespace formatters {
21
LibcxxStdSliceArraySummaryProvider(ValueObject & valobj,Stream & stream,const TypeSummaryOptions & options)22 bool LibcxxStdSliceArraySummaryProvider(ValueObject &valobj, Stream &stream,
23 const TypeSummaryOptions &options) {
24 ValueObjectSP obj = valobj.GetNonSyntheticValue();
25 if (!obj)
26 return false;
27
28 ValueObjectSP ptr_sp = obj->GetChildMemberWithName("__size_");
29 if (!ptr_sp)
30 return false;
31 const size_t size = ptr_sp->GetValueAsUnsigned(0);
32
33 ptr_sp = obj->GetChildMemberWithName("__stride_");
34 if (!ptr_sp)
35 return false;
36 const size_t stride = ptr_sp->GetValueAsUnsigned(0);
37
38 stream.Printf("stride=%zu size=%zu", stride, size);
39
40 return true;
41 }
42
43 /// Data formatter for libc++'s std::slice_array.
44 ///
45 /// A slice_array is created by using:
46 /// operator[](std::slice slicearr);
47 /// and std::slice is created by:
48 /// slice(std::size_t start, std::size_t size, std::size_t stride);
49 /// The std::slice_array has the following members:
50 /// - __vp_ points to std::valarray::__begin_ + @a start
51 /// - __size_ is @a size
52 /// - __stride_is @a stride
53 class LibcxxStdSliceArraySyntheticFrontEnd : public SyntheticChildrenFrontEnd {
54 public:
55 LibcxxStdSliceArraySyntheticFrontEnd(lldb::ValueObjectSP valobj_sp);
56
57 ~LibcxxStdSliceArraySyntheticFrontEnd() override;
58
59 llvm::Expected<uint32_t> CalculateNumChildren() override;
60
61 lldb::ValueObjectSP GetChildAtIndex(uint32_t idx) override;
62
63 lldb::ChildCacheState Update() override;
64
65 bool MightHaveChildren() override;
66
67 size_t GetIndexOfChildWithName(ConstString name) override;
68
69 private:
70 /// A non-owning pointer to slice_array.__vp_.
71 ValueObject *m_start = nullptr;
72 /// slice_array.__size_.
73 size_t m_size = 0;
74 /// slice_array.__stride_.
75 size_t m_stride = 0;
76 /// The type of slice_array's template argument T.
77 CompilerType m_element_type;
78 /// The sizeof slice_array's template argument T.
79 uint32_t m_element_size = 0;
80 };
81
82 } // namespace formatters
83 } // namespace lldb_private
84
85 lldb_private::formatters::LibcxxStdSliceArraySyntheticFrontEnd::
LibcxxStdSliceArraySyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)86 LibcxxStdSliceArraySyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
87 : SyntheticChildrenFrontEnd(*valobj_sp), m_element_type() {
88 if (valobj_sp)
89 Update();
90 }
91
92 lldb_private::formatters::LibcxxStdSliceArraySyntheticFrontEnd::
~LibcxxStdSliceArraySyntheticFrontEnd()93 ~LibcxxStdSliceArraySyntheticFrontEnd() {
94 // these need to stay around because they are child objects who will follow
95 // their parent's life cycle
96 // delete m_start;
97 }
98
99 llvm::Expected<uint32_t> lldb_private::formatters::
CalculateNumChildren()100 LibcxxStdSliceArraySyntheticFrontEnd::CalculateNumChildren() {
101 return m_size;
102 }
103
104 lldb::ValueObjectSP
GetChildAtIndex(uint32_t idx)105 lldb_private::formatters::LibcxxStdSliceArraySyntheticFrontEnd::GetChildAtIndex(
106 uint32_t idx) {
107 if (!m_start)
108 return lldb::ValueObjectSP();
109
110 uint64_t offset = idx * m_stride * m_element_size;
111 offset = offset + m_start->GetValueAsUnsigned(0);
112 StreamString name;
113 name.Printf("[%" PRIu64 "]", (uint64_t)idx);
114 return CreateValueObjectFromAddress(name.GetString(), offset,
115 m_backend.GetExecutionContextRef(),
116 m_element_type);
117 }
118
119 lldb::ChildCacheState
Update()120 lldb_private::formatters::LibcxxStdSliceArraySyntheticFrontEnd::Update() {
121 m_start = nullptr;
122
123 CompilerType type = m_backend.GetCompilerType();
124 if (type.GetNumTemplateArguments() == 0)
125 return ChildCacheState::eRefetch;
126
127 m_element_type = type.GetTypeTemplateArgument(0);
128 if (std::optional<uint64_t> size = m_element_type.GetByteSize(nullptr))
129 m_element_size = *size;
130
131 if (m_element_size == 0)
132 return ChildCacheState::eRefetch;
133
134 ValueObjectSP start = m_backend.GetChildMemberWithName("__vp_");
135 ValueObjectSP size = m_backend.GetChildMemberWithName("__size_");
136 ValueObjectSP stride = m_backend.GetChildMemberWithName("__stride_");
137
138 if (!start || !size || !stride)
139 return ChildCacheState::eRefetch;
140
141 m_start = start.get();
142 m_size = size->GetValueAsUnsigned(0);
143 m_stride = stride->GetValueAsUnsigned(0);
144
145 return ChildCacheState::eRefetch;
146 }
147
148 bool lldb_private::formatters::LibcxxStdSliceArraySyntheticFrontEnd::
MightHaveChildren()149 MightHaveChildren() {
150 return true;
151 }
152
153 size_t lldb_private::formatters::LibcxxStdSliceArraySyntheticFrontEnd::
GetIndexOfChildWithName(ConstString name)154 GetIndexOfChildWithName(ConstString name) {
155 if (!m_start)
156 return std::numeric_limits<size_t>::max();
157 return ExtractIndexFromString(name.GetCString());
158 }
159
160 lldb_private::SyntheticChildrenFrontEnd *
LibcxxStdSliceArraySyntheticFrontEndCreator(CXXSyntheticChildren *,lldb::ValueObjectSP valobj_sp)161 lldb_private::formatters::LibcxxStdSliceArraySyntheticFrontEndCreator(
162 CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
163 if (!valobj_sp)
164 return nullptr;
165 return new LibcxxStdSliceArraySyntheticFrontEnd(valobj_sp);
166 }
167