Bug Summary

File:build/source/lldb/source/Plugins/Language/CPlusPlus/BlockPointer.cpp
Warning:line 184, column 3
Potential leak of memory pointed to by 'synthetic_children'

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name BlockPointer.cpp -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mframe-pointer=none -fmath-errno -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -ffunction-sections -fdata-sections -fcoverage-compilation-dir=/build/source/build-llvm/tools/clang/stage2-bins -resource-dir /usr/lib/llvm-17/lib/clang/17 -isystem /usr/include/libxml2 -D HAVE_ROUND -D _DEBUG -D _GLIBCXX_ASSERTIONS -D _GNU_SOURCE -D _LIBCPP_ENABLE_ASSERTIONS -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I tools/lldb/source/Plugins/Language/CPlusPlus -I /build/source/lldb/source/Plugins/Language/CPlusPlus -I /build/source/lldb/include -I tools/lldb/include -I include -I /build/source/llvm/include -I /usr/include/python3.9 -I /build/source/clang/include -I tools/lldb/../clang/include -I /build/source/lldb/source -I tools/lldb/source -D _FORTIFY_SOURCE=2 -D NDEBUG -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/x86_64-linux-gnu/c++/10 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../include/c++/10/backward -internal-isystem /usr/lib/llvm-17/lib/clang/17/include -internal-isystem /usr/local/include -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/10/../../../../x86_64-linux-gnu/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -fmacro-prefix-map=/build/source/build-llvm/tools/clang/stage2-bins=build-llvm/tools/clang/stage2-bins -fmacro-prefix-map=/build/source/= -fcoverage-prefix-map=/build/source/build-llvm/tools/clang/stage2-bins=build-llvm/tools/clang/stage2-bins -fcoverage-prefix-map=/build/source/= -source-date-epoch 1683717183 -O2 -Wno-unused-command-line-argument -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wno-comment -Wno-misleading-indentation -Wno-deprecated-declarations -Wno-unknown-pragmas -Wno-strict-aliasing -Wno-stringop-truncation -std=c++17 -fdeprecated-macro -fdebug-compilation-dir=/build/source/build-llvm/tools/clang/stage2-bins -fdebug-prefix-map=/build/source/build-llvm/tools/clang/stage2-bins=build-llvm/tools/clang/stage2-bins -fdebug-prefix-map=/build/source/= -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -fcolor-diagnostics -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /tmp/scan-build-2023-05-10-133810-16478-1 -x c++ /build/source/lldb/source/Plugins/Language/CPlusPlus/BlockPointer.cpp
1//===-- BlockPointer.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 "BlockPointer.h"
10
11#include "Plugins/ExpressionParser/Clang/ClangASTImporter.h"
12#include "Plugins/ExpressionParser/Clang/ClangPersistentVariables.h"
13#include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
14#include "lldb/Core/ValueObject.h"
15#include "lldb/DataFormatters/FormattersHelpers.h"
16#include "lldb/Symbol/CompilerType.h"
17#include "lldb/Symbol/TypeSystem.h"
18#include "lldb/Target/Target.h"
19#include "lldb/Utility/LLDBAssert.h"
20#include "lldb/Utility/LLDBLog.h"
21#include "lldb/Utility/Log.h"
22
23using namespace lldb;
24using namespace lldb_private;
25using namespace lldb_private::formatters;
26
27namespace lldb_private {
28namespace formatters {
29
30class BlockPointerSyntheticFrontEnd : public SyntheticChildrenFrontEnd {
31public:
32 BlockPointerSyntheticFrontEnd(lldb::ValueObjectSP valobj_sp)
33 : SyntheticChildrenFrontEnd(*valobj_sp), m_block_struct_type() {
34 CompilerType block_pointer_type(m_backend.GetCompilerType());
35 CompilerType function_pointer_type;
36 block_pointer_type.IsBlockPointerType(&function_pointer_type);
37
38 TargetSP target_sp(m_backend.GetTargetSP());
39
40 if (!target_sp) {
41 return;
42 }
43
44 auto type_system_or_err = target_sp->GetScratchTypeSystemForLanguage(
45 lldb::eLanguageTypeC_plus_plus);
46 if (auto err = type_system_or_err.takeError()) {
47 LLDB_LOG_ERROR(GetLog(LLDBLog::DataFormatters), std::move(err),do { ::lldb_private::Log *log_private = (GetLog(LLDBLog::DataFormatters
)); ::llvm::Error error_private = (std::move(err)); if (log_private
&& error_private) { log_private->FormatError(::std
::move(error_private), "lldb/source/Plugins/Language/CPlusPlus/BlockPointer.cpp"
, __func__, "Failed to get scratch TypeSystemClang"); } else ::
llvm::consumeError(::std::move(error_private)); } while (0)
48 "Failed to get scratch TypeSystemClang")do { ::lldb_private::Log *log_private = (GetLog(LLDBLog::DataFormatters
)); ::llvm::Error error_private = (std::move(err)); if (log_private
&& error_private) { log_private->FormatError(::std
::move(error_private), "lldb/source/Plugins/Language/CPlusPlus/BlockPointer.cpp"
, __func__, "Failed to get scratch TypeSystemClang"); } else ::
llvm::consumeError(::std::move(error_private)); } while (0)
;
49 return;
50 }
51
52 auto ts = block_pointer_type.GetTypeSystem();
53 auto clang_ast_context = ts.dyn_cast_or_null<TypeSystemClang>();
54 if (!clang_ast_context)
55 return;
56
57 std::shared_ptr<ClangASTImporter> clang_ast_importer;
58 auto *state = target_sp->GetPersistentExpressionStateForLanguage(
59 lldb::eLanguageTypeC_plus_plus);
60 if (state) {
61 auto *persistent_vars = llvm::cast<ClangPersistentVariables>(state);
62 clang_ast_importer = persistent_vars->GetClangASTImporter();
63 }
64
65 if (!clang_ast_importer) {
66 return;
67 }
68
69 const char *const isa_name("__isa");
70 const CompilerType isa_type =
71 clang_ast_context->GetBasicType(lldb::eBasicTypeObjCClass);
72 const char *const flags_name("__flags");
73 const CompilerType flags_type =
74 clang_ast_context->GetBasicType(lldb::eBasicTypeInt);
75 const char *const reserved_name("__reserved");
76 const CompilerType reserved_type =
77 clang_ast_context->GetBasicType(lldb::eBasicTypeInt);
78 const char *const FuncPtr_name("__FuncPtr");
79
80 m_block_struct_type = clang_ast_context->CreateStructForIdentifier(
81 ConstString(), {{isa_name, isa_type},
82 {flags_name, flags_type},
83 {reserved_name, reserved_type},
84 {FuncPtr_name, function_pointer_type}});
85 }
86
87 ~BlockPointerSyntheticFrontEnd() override = default;
88
89 size_t CalculateNumChildren() override {
90 const bool omit_empty_base_classes = false;
91 return m_block_struct_type.GetNumChildren(omit_empty_base_classes, nullptr);
92 }
93
94 lldb::ValueObjectSP GetChildAtIndex(size_t idx) override {
95 if (!m_block_struct_type.IsValid()) {
96 return lldb::ValueObjectSP();
97 }
98
99 if (idx >= CalculateNumChildren()) {
100 return lldb::ValueObjectSP();
101 }
102
103 const bool thread_and_frame_only_if_stopped = true;
104 ExecutionContext exe_ctx = m_backend.GetExecutionContextRef().Lock(
105 thread_and_frame_only_if_stopped);
106 const bool transparent_pointers = false;
107 const bool omit_empty_base_classes = false;
108 const bool ignore_array_bounds = false;
109 ValueObject *value_object = nullptr;
110
111 std::string child_name;
112 uint32_t child_byte_size = 0;
113 int32_t child_byte_offset = 0;
114 uint32_t child_bitfield_bit_size = 0;
115 uint32_t child_bitfield_bit_offset = 0;
116 bool child_is_base_class = false;
117 bool child_is_deref_of_parent = false;
118 uint64_t language_flags = 0;
119
120 const CompilerType child_type =
121 m_block_struct_type.GetChildCompilerTypeAtIndex(
122 &exe_ctx, idx, transparent_pointers, omit_empty_base_classes,
123 ignore_array_bounds, child_name, child_byte_size, child_byte_offset,
124 child_bitfield_bit_size, child_bitfield_bit_offset,
125 child_is_base_class, child_is_deref_of_parent, value_object,
126 language_flags);
127
128 ValueObjectSP struct_pointer_sp =
129 m_backend.Cast(m_block_struct_type.GetPointerType());
130
131 if (!struct_pointer_sp) {
132 return lldb::ValueObjectSP();
133 }
134
135 Status err;
136 ValueObjectSP struct_sp = struct_pointer_sp->Dereference(err);
137
138 if (!struct_sp || !err.Success()) {
139 return lldb::ValueObjectSP();
140 }
141
142 ValueObjectSP child_sp(struct_sp->GetSyntheticChildAtOffset(
143 child_byte_offset, child_type, true,
144 ConstString(child_name.c_str(), child_name.size())));
145
146 return child_sp;
147 }
148
149 // return true if this object is now safe to use forever without ever
150 // updating again; the typical (and tested) answer here is 'false'
151 bool Update() override { return false; }
152
153 // maybe return false if the block pointer is, say, null
154 bool MightHaveChildren() override { return true; }
155
156 size_t GetIndexOfChildWithName(ConstString name) override {
157 if (!m_block_struct_type.IsValid())
158 return UINT32_MAX(4294967295U);
159
160 const bool omit_empty_base_classes = false;
161 return m_block_struct_type.GetIndexOfChildWithName(name.AsCString(),
162 omit_empty_base_classes);
163 }
164
165private:
166 CompilerType m_block_struct_type;
167};
168
169} // namespace formatters
170} // namespace lldb_private
171
172bool lldb_private::formatters::BlockPointerSummaryProvider(
173 ValueObject &valobj, Stream &s, const TypeSummaryOptions &) {
174 lldb_private::SyntheticChildrenFrontEnd *synthetic_children =
175 BlockPointerSyntheticFrontEndCreator(nullptr, valobj.GetSP());
1
Calling 'BlockPointerSyntheticFrontEndCreator'
4
Returned allocated memory
176 if (!synthetic_children
4.1
'synthetic_children' is non-null
) {
5
Taking false branch
177 return false;
178 }
179
180 synthetic_children->Update();
181
182 static const ConstString s_FuncPtr_name("__FuncPtr");
183
184 lldb::ValueObjectSP child_sp = synthetic_children->GetChildAtIndex(
6
Potential leak of memory pointed to by 'synthetic_children'
185 synthetic_children->GetIndexOfChildWithName(s_FuncPtr_name));
186
187 if (!child_sp) {
188 return false;
189 }
190
191 lldb::ValueObjectSP qualified_child_representation_sp =
192 child_sp->GetQualifiedRepresentationIfAvailable(
193 lldb::eDynamicDontRunTarget, true);
194
195 const char *child_value =
196 qualified_child_representation_sp->GetValueAsCString();
197
198 s.Printf("%s", child_value);
199
200 return true;
201}
202
203lldb_private::SyntheticChildrenFrontEnd *
204lldb_private::formatters::BlockPointerSyntheticFrontEndCreator(
205 CXXSyntheticChildren *, lldb::ValueObjectSP valobj_sp) {
206 if (!valobj_sp)
2
Taking false branch
207 return nullptr;
208 return new BlockPointerSyntheticFrontEnd(valobj_sp);
3
Memory is allocated
209}