1 //===-- ObjectFileBreakpad.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 "Plugins/ObjectFile/Breakpad/ObjectFileBreakpad.h"
10 #include "Plugins/ObjectFile/Breakpad/BreakpadRecords.h"
11 #include "lldb/Core/ModuleSpec.h"
12 #include "lldb/Core/PluginManager.h"
13 #include "lldb/Core/Section.h"
14 
15 using namespace lldb;
16 using namespace lldb_private;
17 using namespace lldb_private::breakpad;
18 
19 LLDB_PLUGIN_DEFINE(ObjectFileBreakpad)
20 
21 namespace {
22 struct Header {
23   ArchSpec arch;
24   UUID uuid;
25   static llvm::Optional<Header> parse(llvm::StringRef text);
26 };
27 } // namespace
28 
29 llvm::Optional<Header> Header::parse(llvm::StringRef text) {
30   llvm::StringRef line;
31   std::tie(line, text) = text.split('\n');
32   auto Module = ModuleRecord::parse(line);
33   if (!Module)
34     return llvm::None;
35 
36   llvm::Triple triple;
37   triple.setArch(Module->Arch);
38   triple.setOS(Module->OS);
39 
40   std::tie(line, text) = text.split('\n');
41 
42   auto Info = InfoRecord::parse(line);
43   UUID uuid = Info && Info->ID ? Info->ID : Module->ID;
44   return Header{ArchSpec(triple), std::move(uuid)};
45 }
46 
47 char ObjectFileBreakpad::ID;
48 
49 void ObjectFileBreakpad::Initialize() {
50   PluginManager::RegisterPlugin(GetPluginNameStatic(),
51                                 GetPluginDescriptionStatic(), CreateInstance,
52                                 CreateMemoryInstance, GetModuleSpecifications);
53 }
54 
55 void ObjectFileBreakpad::Terminate() {
56   PluginManager::UnregisterPlugin(CreateInstance);
57 }
58 
59 ConstString ObjectFileBreakpad::GetPluginNameStatic() {
60   static ConstString g_name("breakpad");
61   return g_name;
62 }
63 
64 ObjectFile *ObjectFileBreakpad::CreateInstance(
65     const ModuleSP &module_sp, DataBufferSP &data_sp, offset_t data_offset,
66     const FileSpec *file, offset_t file_offset, offset_t length) {
67   if (!data_sp) {
68     data_sp = MapFileData(*file, length, file_offset);
69     if (!data_sp)
70       return nullptr;
71     data_offset = 0;
72   }
73   auto text = toStringRef(data_sp->GetData());
74   llvm::Optional<Header> header = Header::parse(text);
75   if (!header)
76     return nullptr;
77 
78   // Update the data to contain the entire file if it doesn't already
79   if (data_sp->GetByteSize() < length) {
80     data_sp = MapFileData(*file, length, file_offset);
81     if (!data_sp)
82       return nullptr;
83     data_offset = 0;
84   }
85 
86   return new ObjectFileBreakpad(module_sp, data_sp, data_offset, file,
87                                 file_offset, length, std::move(header->arch),
88                                 std::move(header->uuid));
89 }
90 
91 ObjectFile *ObjectFileBreakpad::CreateMemoryInstance(
92     const ModuleSP &module_sp, DataBufferSP &data_sp,
93     const ProcessSP &process_sp, addr_t header_addr) {
94   return nullptr;
95 }
96 
97 size_t ObjectFileBreakpad::GetModuleSpecifications(
98     const FileSpec &file, DataBufferSP &data_sp, offset_t data_offset,
99     offset_t file_offset, offset_t length, ModuleSpecList &specs) {
100   auto text = toStringRef(data_sp->GetData());
101   llvm::Optional<Header> header = Header::parse(text);
102   if (!header)
103     return 0;
104   ModuleSpec spec(file, std::move(header->arch));
105   spec.GetUUID() = std::move(header->uuid);
106   specs.Append(spec);
107   return 1;
108 }
109 
110 ObjectFileBreakpad::ObjectFileBreakpad(const ModuleSP &module_sp,
111                                        DataBufferSP &data_sp,
112                                        offset_t data_offset,
113                                        const FileSpec *file, offset_t offset,
114                                        offset_t length, ArchSpec arch,
115                                        UUID uuid)
116     : ObjectFile(module_sp, file, offset, length, data_sp, data_offset),
117       m_arch(std::move(arch)), m_uuid(std::move(uuid)) {}
118 
119 bool ObjectFileBreakpad::ParseHeader() {
120   // We already parsed the header during initialization.
121   return true;
122 }
123 
124 Symtab *ObjectFileBreakpad::GetSymtab() {
125   // TODO
126   return nullptr;
127 }
128 
129 void ObjectFileBreakpad::CreateSections(SectionList &unified_section_list) {
130   if (m_sections_up)
131     return;
132   m_sections_up = std::make_unique<SectionList>();
133 
134   llvm::Optional<Record::Kind> current_section;
135   offset_t section_start;
136   llvm::StringRef text = toStringRef(m_data.GetData());
137   uint32_t next_section_id = 1;
138   auto maybe_add_section = [&](const uint8_t *end_ptr) {
139     if (!current_section)
140       return; // We have been called before parsing the first line.
141 
142     offset_t end_offset = end_ptr - m_data.GetDataStart();
143     auto section_sp = std::make_shared<Section>(
144         GetModule(), this, next_section_id++,
145         ConstString(toString(*current_section)), eSectionTypeOther,
146         /*file_vm_addr*/ 0, /*vm_size*/ 0, section_start,
147         end_offset - section_start, /*log2align*/ 0, /*flags*/ 0);
148     m_sections_up->AddSection(section_sp);
149     unified_section_list.AddSection(section_sp);
150   };
151   while (!text.empty()) {
152     llvm::StringRef line;
153     std::tie(line, text) = text.split('\n');
154 
155     llvm::Optional<Record::Kind> next_section = Record::classify(line);
156     if (next_section == Record::Line) {
157       // Line records logically belong to the preceding Func record, so we put
158       // them in the same section.
159       next_section = Record::Func;
160     }
161     if (next_section == current_section)
162       continue;
163 
164     // Changing sections, finish off the previous one, if there was any.
165     maybe_add_section(line.bytes_begin());
166     // And start a new one.
167     current_section = next_section;
168     section_start = line.bytes_begin() - m_data.GetDataStart();
169   }
170   // Finally, add the last section.
171   maybe_add_section(m_data.GetDataEnd());
172 }
173