1 //===-- LibCxxInitializerList.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 "lldb/Utility/ConstString.h"
14 #include <optional>
15 
16 using namespace lldb;
17 using namespace lldb_private;
18 using namespace lldb_private::formatters;
19 
20 namespace lldb_private {
21 namespace formatters {
22 class LibcxxInitializerListSyntheticFrontEnd
23     : public SyntheticChildrenFrontEnd {
24 public:
25   LibcxxInitializerListSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp);
26 
27   ~LibcxxInitializerListSyntheticFrontEnd() override;
28 
29   size_t CalculateNumChildren() override;
30 
31   lldb::ValueObjectSP GetChildAtIndex(size_t idx) override;
32 
33   bool Update() override;
34 
35   bool MightHaveChildren() override;
36 
37   size_t GetIndexOfChildWithName(ConstString name) override;
38 
39 private:
40   ValueObject *m_start = nullptr;
41   CompilerType m_element_type;
42   uint32_t m_element_size = 0;
43   size_t m_num_elements = 0;
44 };
45 } // namespace formatters
46 } // namespace lldb_private
47 
48 lldb_private::formatters::LibcxxInitializerListSyntheticFrontEnd::
49     LibcxxInitializerListSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
50     : SyntheticChildrenFrontEnd(*valobj_sp), m_element_type() {
51   if (valobj_sp)
52     Update();
53 }
54 
55 lldb_private::formatters::LibcxxInitializerListSyntheticFrontEnd::
56     ~LibcxxInitializerListSyntheticFrontEnd() {
57   // this needs to stay around because it's a child object who will follow its
58   // parent's life cycle
59   // delete m_start;
60 }
61 
62 size_t lldb_private::formatters::LibcxxInitializerListSyntheticFrontEnd::
63     CalculateNumChildren() {
64   m_num_elements = 0;
65   ValueObjectSP size_sp(m_backend.GetChildMemberWithName("__size_"));
66   if (size_sp)
67     m_num_elements = size_sp->GetValueAsUnsigned(0);
68   return m_num_elements;
69 }
70 
71 lldb::ValueObjectSP lldb_private::formatters::
72     LibcxxInitializerListSyntheticFrontEnd::GetChildAtIndex(size_t idx) {
73   if (!m_start)
74     return lldb::ValueObjectSP();
75 
76   uint64_t offset = idx * m_element_size;
77   offset = offset + m_start->GetValueAsUnsigned(0);
78   StreamString name;
79   name.Printf("[%" PRIu64 "]", (uint64_t)idx);
80   return CreateValueObjectFromAddress(name.GetString(), offset,
81                                       m_backend.GetExecutionContextRef(),
82                                       m_element_type);
83 }
84 
85 bool lldb_private::formatters::LibcxxInitializerListSyntheticFrontEnd::
86     Update() {
87   m_start = nullptr;
88   m_num_elements = 0;
89   m_element_type = m_backend.GetCompilerType().GetTypeTemplateArgument(0);
90   if (!m_element_type.IsValid())
91     return false;
92 
93   if (std::optional<uint64_t> size = m_element_type.GetByteSize(nullptr)) {
94     m_element_size = *size;
95     // Store raw pointers or end up with a circular dependency.
96     m_start = m_backend.GetChildMemberWithName("__begin_").get();
97   }
98 
99   return false;
100 }
101 
102 bool lldb_private::formatters::LibcxxInitializerListSyntheticFrontEnd::
103     MightHaveChildren() {
104   return true;
105 }
106 
107 size_t lldb_private::formatters::LibcxxInitializerListSyntheticFrontEnd::
108     GetIndexOfChildWithName(ConstString name) {
109   if (!m_start)
110     return UINT32_MAX;
111   return ExtractIndexFromString(name.GetCString());
112 }
113 
114 lldb_private::SyntheticChildrenFrontEnd *
115 lldb_private::formatters::LibcxxInitializerListSyntheticFrontEndCreator(
116     CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
117   return (valobj_sp ? new LibcxxInitializerListSyntheticFrontEnd(valobj_sp)
118                     : nullptr);
119 }
120