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 
15 using namespace lldb;
16 using namespace lldb_private;
17 using namespace lldb_private::formatters;
18 
19 namespace lldb_private {
20 namespace formatters {
21 class LibcxxInitializerListSyntheticFrontEnd
22     : public SyntheticChildrenFrontEnd {
23 public:
24   LibcxxInitializerListSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp);
25 
26   ~LibcxxInitializerListSyntheticFrontEnd() override;
27 
28   size_t CalculateNumChildren() override;
29 
30   lldb::ValueObjectSP GetChildAtIndex(size_t idx) override;
31 
32   bool Update() override;
33 
34   bool MightHaveChildren() override;
35 
36   size_t GetIndexOfChildWithName(ConstString name) override;
37 
38 private:
39   ValueObject *m_start;
40   CompilerType m_element_type;
41   uint32_t m_element_size;
42   size_t m_num_elements;
43 };
44 } // namespace formatters
45 } // namespace lldb_private
46 
47 lldb_private::formatters::LibcxxInitializerListSyntheticFrontEnd::
48     LibcxxInitializerListSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
49     : SyntheticChildrenFrontEnd(*valobj_sp), m_start(nullptr), m_element_type(),
50       m_element_size(0), m_num_elements(0) {
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   static ConstString g___size_("__size_");
65   m_num_elements = 0;
66   ValueObjectSP size_sp(m_backend.GetChildMemberWithName(g___size_, true));
67   if (size_sp)
68     m_num_elements = size_sp->GetValueAsUnsigned(0);
69   return m_num_elements;
70 }
71 
72 lldb::ValueObjectSP lldb_private::formatters::
73     LibcxxInitializerListSyntheticFrontEnd::GetChildAtIndex(size_t idx) {
74   if (!m_start)
75     return lldb::ValueObjectSP();
76 
77   uint64_t offset = idx * m_element_size;
78   offset = offset + m_start->GetValueAsUnsigned(0);
79   StreamString name;
80   name.Printf("[%" PRIu64 "]", (uint64_t)idx);
81   return CreateValueObjectFromAddress(name.GetString(), offset,
82                                       m_backend.GetExecutionContextRef(),
83                                       m_element_type);
84 }
85 
86 bool lldb_private::formatters::LibcxxInitializerListSyntheticFrontEnd::
87     Update() {
88   static ConstString g___begin_("__begin_");
89 
90   m_start = nullptr;
91   m_num_elements = 0;
92   m_element_type = m_backend.GetCompilerType().GetTypeTemplateArgument(0);
93   if (!m_element_type.IsValid())
94     return false;
95 
96   if (llvm::Optional<uint64_t> size = m_element_type.GetByteSize(nullptr)) {
97     m_element_size = *size;
98     // Store raw pointers or end up with a circular dependency.
99     m_start = m_backend.GetChildMemberWithName(g___begin_, true).get();
100   }
101 
102   return false;
103 }
104 
105 bool lldb_private::formatters::LibcxxInitializerListSyntheticFrontEnd::
106     MightHaveChildren() {
107   return true;
108 }
109 
110 size_t lldb_private::formatters::LibcxxInitializerListSyntheticFrontEnd::
111     GetIndexOfChildWithName(ConstString name) {
112   if (!m_start)
113     return UINT32_MAX;
114   return ExtractIndexFromString(name.GetCString());
115 }
116 
117 lldb_private::SyntheticChildrenFrontEnd *
118 lldb_private::formatters::LibcxxInitializerListSyntheticFrontEndCreator(
119     CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
120   return (valobj_sp ? new LibcxxInitializerListSyntheticFrontEnd(valobj_sp)
121                     : nullptr);
122 }
123