1 //===-- ObjectFileJIT.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 "llvm/ADT/StringRef.h"
10 
11 #include "lldb/Core/Module.h"
12 #include "lldb/Core/ModuleSpec.h"
13 #include "lldb/Core/PluginManager.h"
14 #include "lldb/Core/Section.h"
15 #include "lldb/Expression/ObjectFileJIT.h"
16 #include "lldb/Target/Process.h"
17 #include "lldb/Target/SectionLoadList.h"
18 #include "lldb/Target/Target.h"
19 #include "lldb/Utility/ArchSpec.h"
20 #include "lldb/Utility/DataBuffer.h"
21 #include "lldb/Utility/DataBufferHeap.h"
22 #include "lldb/Utility/FileSpec.h"
23 #include "lldb/Utility/FileSpecList.h"
24 #include "lldb/Utility/Log.h"
25 #include "lldb/Utility/Timer.h"
26 #include "lldb/Utility/UUID.h"
27 
28 using namespace lldb;
29 using namespace lldb_private;
30 
31 char ObjectFileJIT::ID;
32 
33 void ObjectFileJIT::Initialize() {
34   PluginManager::RegisterPlugin(GetPluginNameStatic(),
35                                 GetPluginDescriptionStatic(), CreateInstance,
36                                 CreateMemoryInstance, GetModuleSpecifications);
37 }
38 
39 void ObjectFileJIT::Terminate() {
40   PluginManager::UnregisterPlugin(CreateInstance);
41 }
42 
43 ObjectFile *ObjectFileJIT::CreateInstance(const lldb::ModuleSP &module_sp,
44                                           DataBufferSP data_sp,
45                                           lldb::offset_t data_offset,
46                                           const FileSpec *file,
47                                           lldb::offset_t file_offset,
48                                           lldb::offset_t length) {
49   // JIT'ed object file is backed by the ObjectFileJITDelegate, never read from
50   // a file
51   return nullptr;
52 }
53 
54 ObjectFile *ObjectFileJIT::CreateMemoryInstance(const lldb::ModuleSP &module_sp,
55                                                 WritableDataBufferSP data_sp,
56                                                 const ProcessSP &process_sp,
57                                                 lldb::addr_t header_addr) {
58   // JIT'ed object file is backed by the ObjectFileJITDelegate, never read from
59   // memory
60   return nullptr;
61 }
62 
63 size_t ObjectFileJIT::GetModuleSpecifications(
64     const lldb_private::FileSpec &file, lldb::DataBufferSP &data_sp,
65     lldb::offset_t data_offset, lldb::offset_t file_offset,
66     lldb::offset_t length, lldb_private::ModuleSpecList &specs) {
67   // JIT'ed object file can't be read from a file on disk
68   return 0;
69 }
70 
71 ObjectFileJIT::ObjectFileJIT(const lldb::ModuleSP &module_sp,
72                              const ObjectFileJITDelegateSP &delegate_sp)
73     : ObjectFile(module_sp, nullptr, 0, 0, DataBufferSP(), 0), m_delegate_wp() {
74   if (delegate_sp) {
75     m_delegate_wp = delegate_sp;
76     m_data.SetByteOrder(delegate_sp->GetByteOrder());
77     m_data.SetAddressByteSize(delegate_sp->GetAddressByteSize());
78   }
79 }
80 
81 ObjectFileJIT::~ObjectFileJIT() = default;
82 
83 bool ObjectFileJIT::ParseHeader() {
84   // JIT code is never in a file, nor is it required to have any header
85   return false;
86 }
87 
88 ByteOrder ObjectFileJIT::GetByteOrder() const { return m_data.GetByteOrder(); }
89 
90 bool ObjectFileJIT::IsExecutable() const { return false; }
91 
92 uint32_t ObjectFileJIT::GetAddressByteSize() const {
93   return m_data.GetAddressByteSize();
94 }
95 
96 void ObjectFileJIT::ParseSymtab(Symtab &symtab) {
97   ObjectFileJITDelegateSP delegate_sp(m_delegate_wp.lock());
98   if (delegate_sp)
99     delegate_sp->PopulateSymtab(this, symtab);
100 }
101 
102 bool ObjectFileJIT::IsStripped() {
103   return false; // JIT code that is in a module is never stripped
104 }
105 
106 void ObjectFileJIT::CreateSections(SectionList &unified_section_list) {
107   if (!m_sections_up) {
108     m_sections_up = std::make_unique<SectionList>();
109     ObjectFileJITDelegateSP delegate_sp(m_delegate_wp.lock());
110     if (delegate_sp) {
111       delegate_sp->PopulateSectionList(this, *m_sections_up);
112       unified_section_list = *m_sections_up;
113     }
114   }
115 }
116 
117 void ObjectFileJIT::Dump(Stream *s) {
118   ModuleSP module_sp(GetModule());
119   if (module_sp) {
120     std::lock_guard<std::recursive_mutex> guard(module_sp->GetMutex());
121     s->Printf("%p: ", static_cast<void *>(this));
122     s->Indent();
123     s->PutCString("ObjectFileJIT");
124 
125     if (ArchSpec arch = GetArchitecture())
126       *s << ", arch = " << arch.GetArchitectureName();
127 
128     s->EOL();
129 
130     SectionList *sections = GetSectionList();
131     if (sections)
132       sections->Dump(s->AsRawOstream(), s->GetIndentLevel(), nullptr, true,
133                      UINT32_MAX);
134 
135     if (m_symtab_up)
136       m_symtab_up->Dump(s, nullptr, eSortOrderNone);
137   }
138 }
139 
140 UUID ObjectFileJIT::GetUUID() {
141   // TODO: maybe get from delegate, not needed for first pass
142   return UUID();
143 }
144 
145 uint32_t ObjectFileJIT::GetDependentModules(FileSpecList &files) {
146   // JIT modules don't have dependencies, but they could
147   // if external functions are called and we know where they are
148   files.Clear();
149   return 0;
150 }
151 
152 lldb_private::Address ObjectFileJIT::GetEntryPointAddress() {
153   return Address();
154 }
155 
156 lldb_private::Address ObjectFileJIT::GetBaseAddress() { return Address(); }
157 
158 ObjectFile::Type ObjectFileJIT::CalculateType() { return eTypeJIT; }
159 
160 ObjectFile::Strata ObjectFileJIT::CalculateStrata() { return eStrataJIT; }
161 
162 ArchSpec ObjectFileJIT::GetArchitecture() {
163   if (ObjectFileJITDelegateSP delegate_sp = m_delegate_wp.lock())
164     return delegate_sp->GetArchitecture();
165   return ArchSpec();
166 }
167 
168 bool ObjectFileJIT::SetLoadAddress(Target &target, lldb::addr_t value,
169                                    bool value_is_offset) {
170   size_t num_loaded_sections = 0;
171   SectionList *section_list = GetSectionList();
172   if (section_list) {
173     const size_t num_sections = section_list->GetSize();
174     // "value" is an offset to apply to each top level segment
175     for (size_t sect_idx = 0; sect_idx < num_sections; ++sect_idx) {
176       // Iterate through the object file sections to find all of the sections
177       // that size on disk (to avoid __PAGEZERO) and load them
178       SectionSP section_sp(section_list->GetSectionAtIndex(sect_idx));
179       if (section_sp && section_sp->GetFileSize() > 0 &&
180           !section_sp->IsThreadSpecific()) {
181         if (target.GetSectionLoadList().SetSectionLoadAddress(
182                 section_sp, section_sp->GetFileAddress() + value))
183           ++num_loaded_sections;
184       }
185     }
186   }
187   return num_loaded_sections > 0;
188 }
189 
190 size_t ObjectFileJIT::ReadSectionData(lldb_private::Section *section,
191                                       lldb::offset_t section_offset, void *dst,
192                                       size_t dst_len) {
193   lldb::offset_t file_size = section->GetFileSize();
194   if (section_offset < file_size) {
195     size_t src_len = file_size - section_offset;
196     if (src_len > dst_len)
197       src_len = dst_len;
198     const uint8_t *src =
199         ((uint8_t *)(uintptr_t)section->GetFileOffset()) + section_offset;
200 
201     memcpy(dst, src, src_len);
202     return src_len;
203   }
204   return 0;
205 }
206 
207 size_t
208 ObjectFileJIT::ReadSectionData(lldb_private::Section *section,
209                                lldb_private::DataExtractor &section_data) {
210   if (section->GetFileSize()) {
211     const void *src = (void *)(uintptr_t)section->GetFileOffset();
212 
213     DataBufferSP data_sp =
214         std::make_shared<DataBufferHeap>(src, section->GetFileSize());
215     section_data.SetData(data_sp, 0, data_sp->GetByteSize());
216     section_data.SetByteOrder(GetByteOrder());
217     section_data.SetAddressByteSize(GetAddressByteSize());
218     return section_data.GetByteSize();
219   }
220   section_data.Clear();
221   return 0;
222 }
223