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/LocateSymbolFile.h"
20 #include "lldb/Symbol/ObjectFile.h"
21 #include "lldb/Target/Target.h"
22 #include "lldb/Utility/StreamString.h"
23 #include "lldb/Utility/Timer.h"
24 
25 using namespace lldb;
26 using namespace lldb_private;
27 
28 LLDB_PLUGIN_DEFINE(SymbolVendorELF)
29 
30 // SymbolVendorELF constructor
31 SymbolVendorELF::SymbolVendorELF(const lldb::ModuleSP &module_sp)
32     : SymbolVendor(module_sp) {}
33 
34 void SymbolVendorELF::Initialize() {
35   PluginManager::RegisterPlugin(GetPluginNameStatic(),
36                                 GetPluginDescriptionStatic(), CreateInstance);
37 }
38 
39 void SymbolVendorELF::Terminate() {
40   PluginManager::UnregisterPlugin(CreateInstance);
41 }
42 
43 llvm::StringRef SymbolVendorELF::GetPluginDescriptionStatic() {
44   return "Symbol vendor for ELF that looks for dSYM files that match "
45          "executables.";
46 }
47 
48 // CreateInstance
49 //
50 // Platforms can register a callback to use when creating symbol vendors to
51 // allow for complex debug information file setups, and to also allow for
52 // finding separate debug information files.
53 SymbolVendor *
54 SymbolVendorELF::CreateInstance(const lldb::ModuleSP &module_sp,
55                                 lldb_private::Stream *feedback_strm) {
56   if (!module_sp)
57     return nullptr;
58 
59   ObjectFileELF *obj_file =
60       llvm::dyn_cast_or_null<ObjectFileELF>(module_sp->GetObjectFile());
61   if (!obj_file)
62     return nullptr;
63 
64   lldb_private::UUID uuid = obj_file->GetUUID();
65   if (!uuid)
66     return nullptr;
67 
68   // If the main object file already contains debug info, then we are done.
69   if (obj_file->GetSectionList()->FindSectionByType(
70           lldb::eSectionTypeDWARFDebugInfo, true))
71     return nullptr;
72 
73   // If the module specified a filespec, use that.
74   FileSpec fspec = module_sp->GetSymbolFileFileSpec();
75   // Otherwise, try gnu_debuglink, if one exists.
76   if (!fspec)
77     fspec = obj_file->GetDebugLink().value_or(FileSpec());
78 
79   LLDB_SCOPED_TIMERF("SymbolVendorELF::CreateInstance (module = %s)",
80                      module_sp->GetFileSpec().GetPath().c_str());
81 
82   ModuleSpec module_spec;
83 
84   module_spec.GetFileSpec() = obj_file->GetFileSpec();
85   FileSystem::Instance().Resolve(module_spec.GetFileSpec());
86   module_spec.GetSymbolFileSpec() = fspec;
87   module_spec.GetUUID() = uuid;
88   FileSpecList search_paths = Target::GetDefaultDebugFileSearchPaths();
89   FileSpec dsym_fspec =
90       Symbols::LocateExecutableSymbolFile(module_spec, search_paths);
91   if (!dsym_fspec)
92     return nullptr;
93 
94   DataBufferSP dsym_file_data_sp;
95   lldb::offset_t dsym_file_data_offset = 0;
96   ObjectFileSP dsym_objfile_sp = ObjectFile::FindPlugin(
97       module_sp, &dsym_fspec, 0, FileSystem::Instance().GetByteSize(dsym_fspec),
98       dsym_file_data_sp, dsym_file_data_offset);
99   if (!dsym_objfile_sp)
100     return nullptr;
101 
102   // This objfile is for debugging purposes. Sadly, ObjectFileELF won't
103   // be able to figure this out consistently as the symbol file may not
104   // have stripped the code sections, etc.
105   dsym_objfile_sp->SetType(ObjectFile::eTypeDebugInfo);
106 
107   SymbolVendorELF *symbol_vendor = new SymbolVendorELF(module_sp);
108 
109   // Get the module unified section list and add our debug sections to
110   // that.
111   SectionList *module_section_list = module_sp->GetSectionList();
112   SectionList *objfile_section_list = dsym_objfile_sp->GetSectionList();
113 
114   static const SectionType g_sections[] = {
115       eSectionTypeDWARFDebugAbbrev,     eSectionTypeDWARFDebugAddr,
116       eSectionTypeDWARFDebugAranges,    eSectionTypeDWARFDebugCuIndex,
117       eSectionTypeDWARFDebugFrame,      eSectionTypeDWARFDebugInfo,
118       eSectionTypeDWARFDebugLine,       eSectionTypeDWARFDebugLineStr,
119       eSectionTypeDWARFDebugLoc,        eSectionTypeDWARFDebugLocLists,
120       eSectionTypeDWARFDebugMacInfo,    eSectionTypeDWARFDebugMacro,
121       eSectionTypeDWARFDebugNames,      eSectionTypeDWARFDebugPubNames,
122       eSectionTypeDWARFDebugPubTypes,   eSectionTypeDWARFDebugRanges,
123       eSectionTypeDWARFDebugRngLists,   eSectionTypeDWARFDebugStr,
124       eSectionTypeDWARFDebugStrOffsets, eSectionTypeDWARFDebugTypes,
125       eSectionTypeELFSymbolTable,       eSectionTypeDWARFGNUDebugAltLink,
126   };
127   for (SectionType section_type : g_sections) {
128     if (SectionSP section_sp =
129             objfile_section_list->FindSectionByType(section_type, true)) {
130       if (SectionSP module_section_sp =
131               module_section_list->FindSectionByType(section_type, true))
132         module_section_list->ReplaceSection(module_section_sp->GetID(),
133                                             section_sp);
134       else
135         module_section_list->AddSection(section_sp);
136     }
137   }
138 
139   symbol_vendor->AddSymbolFileRepresentation(dsym_objfile_sp);
140   return symbol_vendor;
141 }
142