Bug Summary

File:tools/lldb/source/Plugins/Language/CPlusPlus/BlockPointer.cpp
Warning:line 186, column 34
Potential leak of memory pointed to by 'synthetic_children'

Annotated Source Code

1//===-- BlockPointer.cpp ----------------------------------------*- C++ -*-===//
2//
3// The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10// C Includes
11// C++ Includes
12// Other libraries and framework includes
13// Project includes
14#include "BlockPointer.h"
15
16#include "lldb/Core/ValueObject.h"
17#include "lldb/DataFormatters/FormattersHelpers.h"
18#include "lldb/Symbol/ClangASTContext.h"
19#include "lldb/Symbol/ClangASTImporter.h"
20#include "lldb/Symbol/CompilerType.h"
21#include "lldb/Symbol/TypeSystem.h"
22#include "lldb/Target/Target.h"
23
24#include "lldb/Utility/LLDBAssert.h"
25
26using namespace lldb;
27using namespace lldb_private;
28using namespace lldb_private::formatters;
29
30namespace lldb_private {
31namespace formatters {
32
33class BlockPointerSyntheticFrontEnd : public SyntheticChildrenFrontEnd {
34public:
35 BlockPointerSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
36 : SyntheticChildrenFrontEnd(*valobj_sp), m_block_struct_type() {
37 CompilerType block_pointer_type(m_backend.GetCompilerType());
38 CompilerType function_pointer_type;
39 block_pointer_type.IsBlockPointerType(&function_pointer_type);
40
41 TargetSP target_sp(m_backend.GetTargetSP());
42
43 if (!target_sp) {
44 return;
45 }
46
47 Error err;
48 TypeSystem *type_system = target_sp->GetScratchTypeSystemForLanguage(
49 &err, lldb::eLanguageTypeC_plus_plus);
50
51 if (!err.Success() || !type_system) {
52 return;
53 }
54
55 ClangASTContext *clang_ast_context =
56 llvm::dyn_cast<ClangASTContext>(type_system);
57
58 if (!clang_ast_context) {
59 return;
60 }
61
62 ClangASTImporterSP clang_ast_importer = target_sp->GetClangASTImporter();
63
64 if (!clang_ast_importer) {
65 return;
66 }
67
68 const char *const isa_name("__isa");
69 const CompilerType isa_type =
70 clang_ast_context->GetBasicType(lldb::eBasicTypeObjCClass);
71 const char *const flags_name("__flags");
72 const CompilerType flags_type =
73 clang_ast_context->GetBasicType(lldb::eBasicTypeInt);
74 const char *const reserved_name("__reserved");
75 const CompilerType reserved_type =
76 clang_ast_context->GetBasicType(lldb::eBasicTypeInt);
77 const char *const FuncPtr_name("__FuncPtr");
78 const CompilerType FuncPtr_type =
79 clang_ast_importer->CopyType(*clang_ast_context, function_pointer_type);
80
81 m_block_struct_type = clang_ast_context->CreateStructForIdentifier(
82 ConstString(), {{isa_name, isa_type},
83 {flags_name, flags_type},
84 {reserved_name, reserved_type},
85 {FuncPtr_name, FuncPtr_type}});
86 }
87
88 ~BlockPointerSyntheticFrontEnd() override = default;
89
90 size_t CalculateNumChildren() override {
91 const bool omit_empty_base_classes = false;
92 return m_block_struct_type.GetNumChildren(omit_empty_base_classes);
93 }
94
95 lldb::ValueObjectSP GetChildAtIndex(size_t idx) override {
96 if (!m_block_struct_type.IsValid()) {
97 return lldb::ValueObjectSP();
98 }
99
100 if (idx >= CalculateNumChildren()) {
101 return lldb::ValueObjectSP();
102 }
103
104 const bool thread_and_frame_only_if_stopped = true;
105 ExecutionContext exe_ctx = m_backend.GetExecutionContextRef().Lock(
106 thread_and_frame_only_if_stopped);
107 const bool transparent_pointers = false;
108 const bool omit_empty_base_classes = false;
109 const bool ignore_array_bounds = false;
110 ValueObject *value_object = nullptr;
111
112 std::string child_name;
113 uint32_t child_byte_size = 0;
114 int32_t child_byte_offset = 0;
115 uint32_t child_bitfield_bit_size = 0;
116 uint32_t child_bitfield_bit_offset = 0;
117 bool child_is_base_class = false;
118 bool child_is_deref_of_parent = false;
119 uint64_t language_flags = 0;
120
121 const CompilerType child_type =
122 m_block_struct_type.GetChildCompilerTypeAtIndex(
123 &exe_ctx, idx, transparent_pointers, omit_empty_base_classes,
124 ignore_array_bounds, child_name, child_byte_size, child_byte_offset,
125 child_bitfield_bit_size, child_bitfield_bit_offset,
126 child_is_base_class, child_is_deref_of_parent, value_object,
127 language_flags);
128
129 ValueObjectSP struct_pointer_sp =
130 m_backend.Cast(m_block_struct_type.GetPointerType());
131
132 if (!struct_pointer_sp) {
133 return lldb::ValueObjectSP();
134 }
135
136 Error err;
137 ValueObjectSP struct_sp = struct_pointer_sp->Dereference(err);
138
139 if (!struct_sp || !err.Success()) {
140 return lldb::ValueObjectSP();
141 }
142
143 ValueObjectSP child_sp(struct_sp->GetSyntheticChildAtOffset(
144 child_byte_offset, child_type, true,
145 ConstString(child_name.c_str(), child_name.size())));
146
147 return child_sp;
148 }
149
150 // return true if this object is now safe to use forever without
151 // ever updating again; the typical (and tested) answer here is
152 // 'false'
153 bool Update() override { return false; }
154
155 // maybe return false if the block pointer is, say, null
156 bool MightHaveChildren() override { return true; }
157
158 size_t GetIndexOfChildWithName(const ConstString &name) override {
159 if (!m_block_struct_type.IsValid())
160 return UINT32_MAX(4294967295U);
161
162 const bool omit_empty_base_classes = false;
163 return m_block_struct_type.GetIndexOfChildWithName(name.AsCString(),
164 omit_empty_base_classes);
165 }
166
167private:
168 CompilerType m_block_struct_type;
169};
170
171} // namespace formatters
172} // namespace lldb_private
173
174bool lldb_private::formatters::BlockPointerSummaryProvider(
175 ValueObject &valobj, Stream &s, const TypeSummaryOptions &) {
176 lldb_private::SyntheticChildrenFrontEnd *synthetic_children =
177 BlockPointerSyntheticFrontEndCreator(nullptr, valobj.GetSP());
1
Calling 'BlockPointerSyntheticFrontEndCreator'
5
Returned allocated memory
178 if (!synthetic_children) {
6
Taking false branch
179 return false;
180 }
181
182 synthetic_children->Update();
183
184 static const ConstString s_FuncPtr_name("__FuncPtr");
185
186 lldb::ValueObjectSP child_sp = synthetic_children->GetChildAtIndex(
7
Potential leak of memory pointed to by 'synthetic_children'
187 synthetic_children->GetIndexOfChildWithName(s_FuncPtr_name));
188
189 if (!child_sp) {
190 return false;
191 }
192
193 lldb::ValueObjectSP qualified_child_representation_sp =
194 child_sp->GetQualifiedRepresentationIfAvailable(
195 lldb::eDynamicDontRunTarget, true);
196
197 const char *child_value =
198 qualified_child_representation_sp->GetValueAsCString();
199
200 s.Printf("%s", child_value);
201
202 return true;
203}
204
205lldb_private::SyntheticChildrenFrontEnd *
206lldb_private::formatters::BlockPointerSyntheticFrontEndCreator(
207 CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
208 if (!valobj_sp)
2
Assuming the condition is false
3
Taking false branch
209 return nullptr;
210 return new BlockPointerSyntheticFrontEnd(valobj_sp);
4
Memory is allocated
211}