1//===-- SymbolVendorELF.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 "SymbolVendorELF.h"
10
11#include <cstring>
12
13#include "Plugins/ObjectFile/ELF/ObjectFileELF.h"
14#include "lldb/Core/Module.h"
15#include "lldb/Core/ModuleSpec.h"
16#include "lldb/Core/PluginManager.h"
17#include "lldb/Core/Section.h"
18#include "lldb/Host/Host.h"
19#include "lldb/Symbol/ObjectFile.h"
20#include "lldb/Target/Target.h"
21#include "lldb/Utility/StreamString.h"
22#include "lldb/Utility/Timer.h"
23
24using namespace lldb;
25using namespace lldb_private;
26
27LLDB_PLUGIN_DEFINE(SymbolVendorELF)
28
29// SymbolVendorELF constructor
30SymbolVendorELF::SymbolVendorELF(const lldb::ModuleSP &module_sp)
31 : SymbolVendor(module_sp) {}
32
33void SymbolVendorELF::Initialize() {
34 PluginManager::RegisterPlugin(name: GetPluginNameStatic(),
35 description: GetPluginDescriptionStatic(), create_callback: CreateInstance);
36}
37
38void SymbolVendorELF::Terminate() {
39 PluginManager::UnregisterPlugin(create_callback: CreateInstance);
40}
41
42llvm::StringRef SymbolVendorELF::GetPluginDescriptionStatic() {
43 return "Symbol vendor for ELF that looks for dSYM files that match "
44 "executables.";
45}
46
47// If this is needed elsewhere, it can be exported/moved.
48static bool IsDwpSymbolFile(const lldb::ModuleSP &module_sp,
49 const FileSpec &file_spec) {
50 DataBufferSP dwp_file_data_sp;
51 lldb::offset_t dwp_file_data_offset = 0;
52 // Try to create an ObjectFile from the file_spec.
53 ObjectFileSP dwp_obj_file = ObjectFile::FindPlugin(
54 module_sp, file_spec: &file_spec, file_offset: 0, file_size: FileSystem::Instance().GetByteSize(file_spec),
55 data_sp&: dwp_file_data_sp, data_offset&: dwp_file_data_offset);
56 // The presence of a debug_cu_index section is the key identifying feature of
57 // a DWP file. Make sure we don't fill in the section list on dwp_obj_file
58 // (by calling GetSectionList(false)) as this function could be called before
59 // we may have all the symbol files collected and available.
60 return dwp_obj_file && ObjectFileELF::classof(obj: dwp_obj_file.get()) &&
61 dwp_obj_file->GetSectionList(update_module_section_list: false)->FindSectionByType(
62 sect_type: eSectionTypeDWARFDebugCuIndex, check_children: false);
63}
64
65// CreateInstance
66//
67// Platforms can register a callback to use when creating symbol vendors to
68// allow for complex debug information file setups, and to also allow for
69// finding separate debug information files.
70SymbolVendor *
71SymbolVendorELF::CreateInstance(const lldb::ModuleSP &module_sp,
72 lldb_private::Stream *feedback_strm) {
73 if (!module_sp)
74 return nullptr;
75
76 ObjectFileELF *obj_file =
77 llvm::dyn_cast_or_null<ObjectFileELF>(Val: module_sp->GetObjectFile());
78 if (!obj_file)
79 return nullptr;
80
81 lldb_private::UUID uuid = obj_file->GetUUID();
82 if (!uuid)
83 return nullptr;
84
85 // If the main object file already contains debug info, then we are done.
86 if (obj_file->GetSectionList()->FindSectionByType(
87 sect_type: lldb::eSectionTypeDWARFDebugInfo, check_children: true))
88 return nullptr;
89
90 // If the module specified a filespec, use that.
91 FileSpec fspec = module_sp->GetSymbolFileFileSpec();
92 // Otherwise, try gnu_debuglink, if one exists.
93 if (!fspec)
94 fspec = obj_file->GetDebugLink().value_or(u: FileSpec());
95
96 LLDB_SCOPED_TIMERF("SymbolVendorELF::CreateInstance (module = %s)",
97 module_sp->GetFileSpec().GetPath().c_str());
98
99 ModuleSpec module_spec;
100
101 module_spec.GetFileSpec() = obj_file->GetFileSpec();
102 FileSystem::Instance().Resolve(file_spec&: module_spec.GetFileSpec());
103 module_spec.GetSymbolFileSpec() = fspec;
104 module_spec.GetUUID() = uuid;
105 FileSpecList search_paths = Target::GetDefaultDebugFileSearchPaths();
106 FileSpec dsym_fspec = PluginManager::LocateExecutableSymbolFile(
107 module_spec, default_search_paths: search_paths, map&: module_sp->GetSymbolLocatorStatistics());
108 if (!dsym_fspec || IsDwpSymbolFile(module_sp, file_spec: dsym_fspec)) {
109 // If we have a stripped binary or if we have a DWP file, SymbolLocator
110 // plugins may be able to give us an unstripped binary or an
111 // 'only-keep-debug' stripped file.
112 ModuleSpec unstripped_spec = PluginManager::LocateExecutableObjectFile(
113 module_spec, map&: module_sp->GetSymbolLocatorStatistics());
114 if (!unstripped_spec)
115 return nullptr;
116 // The default SymbolLocator plugin returns the original binary if no other
117 // plugin finds something better.
118 if (unstripped_spec.GetFileSpec() == module_spec.GetFileSpec())
119 return nullptr;
120 dsym_fspec = unstripped_spec.GetFileSpec();
121 }
122
123 DataBufferSP dsym_file_data_sp;
124 lldb::offset_t dsym_file_data_offset = 0;
125 ObjectFileSP dsym_objfile_sp = ObjectFile::FindPlugin(
126 module_sp, file_spec: &dsym_fspec, file_offset: 0, file_size: FileSystem::Instance().GetByteSize(file_spec: dsym_fspec),
127 data_sp&: dsym_file_data_sp, data_offset&: dsym_file_data_offset);
128 if (!dsym_objfile_sp)
129 return nullptr;
130 // This objfile is for debugging purposes. Sadly, ObjectFileELF won't
131 // be able to figure this out consistently as the symbol file may not
132 // have stripped the code sections, etc.
133 dsym_objfile_sp->SetType(ObjectFile::eTypeDebugInfo);
134
135 SymbolVendorELF *symbol_vendor = new SymbolVendorELF(module_sp);
136
137 // Get the module unified section list and add our debug sections to
138 // that.
139 SectionList *module_section_list = module_sp->GetSectionList();
140 SectionList *objfile_section_list = dsym_objfile_sp->GetSectionList();
141
142 if (!module_section_list || !objfile_section_list)
143 return nullptr;
144
145 static const SectionType g_sections[] = {
146 eSectionTypeDWARFDebugAbbrev, eSectionTypeDWARFDebugAddr,
147 eSectionTypeDWARFDebugAranges, eSectionTypeDWARFDebugCuIndex,
148 eSectionTypeDWARFDebugFrame, eSectionTypeDWARFDebugInfo,
149 eSectionTypeDWARFDebugLine, eSectionTypeDWARFDebugLineStr,
150 eSectionTypeDWARFDebugLoc, eSectionTypeDWARFDebugLocLists,
151 eSectionTypeDWARFDebugMacInfo, eSectionTypeDWARFDebugMacro,
152 eSectionTypeDWARFDebugNames, eSectionTypeDWARFDebugPubNames,
153 eSectionTypeDWARFDebugPubTypes, eSectionTypeDWARFDebugRanges,
154 eSectionTypeDWARFDebugRngLists, eSectionTypeDWARFDebugStr,
155 eSectionTypeDWARFDebugStrOffsets, eSectionTypeDWARFDebugTypes,
156 eSectionTypeELFSymbolTable, eSectionTypeDWARFGNUDebugAltLink,
157 };
158 for (SectionType section_type : g_sections) {
159 if (SectionSP section_sp =
160 objfile_section_list->FindSectionByType(sect_type: section_type, check_children: true)) {
161 if (SectionSP module_section_sp =
162 module_section_list->FindSectionByType(sect_type: section_type, check_children: true))
163 module_section_list->ReplaceSection(sect_id: module_section_sp->GetID(),
164 section_sp);
165 else
166 module_section_list->AddSection(section_sp);
167 }
168 }
169
170 symbol_vendor->AddSymbolFileRepresentation(objfile_sp: dsym_objfile_sp);
171 return symbol_vendor;
172}
173

source code of lldb/source/Plugins/SymbolVendor/ELF/SymbolVendorELF.cpp