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

   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
  24 using namespace lldb;
  25 using namespace lldb_private;
  26
  27 LLDB_PLUGIN_DEFINE(SymbolVendorELF)
  28
  29 // SymbolVendorELF constructor
  30 SymbolVendorELF::SymbolVendorELF(const lldb::ModuleSP &module_sp)
  31     : SymbolVendor(module_sp) {}
  32
  33 void SymbolVendorELF::Initialize() {
  34   PluginManager::RegisterPlugin(GetPluginNameStatic(),
  35                                 GetPluginDescriptionStatic(), CreateInstance);
  36 }
  37
  38 void SymbolVendorELF::Terminate() {
  39   PluginManager::UnregisterPlugin(CreateInstance);
  40 }
  41
  42 llvm::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.
  48 static 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, 0, FileSystem::Instance().GetByteSize(file_spec),
  55       dwp_file_data_sp, 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(dwp_obj_file.get()) &&
  61          dwp_obj_file->GetSectionList(false)->FindSectionByType(
  62              eSectionTypeDWARFDebugCuIndex, 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.
  70 SymbolVendor *
  71 SymbolVendorELF::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>(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           lldb::eSectionTypeDWARFDebugInfo, 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(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(module_spec.GetFileSpec());
 103   module_spec.GetSymbolFileSpec() = fspec;
 104   module_spec.GetUUID() = uuid;
 105   FileSpecList search_paths = Target::GetDefaultDebugFileSearchPaths();
 106   FileSpec dsym_fspec =
 107       PluginManager::LocateExecutableSymbolFile(module_spec, search_paths);
 108   if (!dsym_fspec || IsDwpSymbolFile(module_sp, 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 =
 113         PluginManager::LocateExecutableObjectFile(module_spec);
 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, &dsym_fspec, 0, FileSystem::Instance().GetByteSize(dsym_fspec),
 127       dsym_file_data_sp, dsym_file_data_offset);
 128   if (!dsym_objfile_sp)
 129     return nullptr;
 130
 131   // This objfile is for debugging purposes. Sadly, ObjectFileELF won't
 132   // be able to figure this out consistently as the symbol file may not
 133   // have stripped the code sections, etc.
 134   dsym_objfile_sp->SetType(ObjectFile::eTypeDebugInfo);
 135
 136   SymbolVendorELF *symbol_vendor = new SymbolVendorELF(module_sp);
 137
 138   // Get the module unified section list and add our debug sections to
 139   // that.
 140   SectionList *module_section_list = module_sp->GetSectionList();
 141   SectionList *objfile_section_list = dsym_objfile_sp->GetSectionList();
 142
 143   if (!module_section_list || !objfile_section_list)
 144     return nullptr;
 145
 146   static const SectionType g_sections[] = {
 147       eSectionTypeDWARFDebugAbbrev,     eSectionTypeDWARFDebugAddr,
 148       eSectionTypeDWARFDebugAranges,    eSectionTypeDWARFDebugCuIndex,
 149       eSectionTypeDWARFDebugFrame,      eSectionTypeDWARFDebugInfo,
 150       eSectionTypeDWARFDebugLine,       eSectionTypeDWARFDebugLineStr,
 151       eSectionTypeDWARFDebugLoc,        eSectionTypeDWARFDebugLocLists,
 152       eSectionTypeDWARFDebugMacInfo,    eSectionTypeDWARFDebugMacro,
 153       eSectionTypeDWARFDebugNames,      eSectionTypeDWARFDebugPubNames,
 154       eSectionTypeDWARFDebugPubTypes,   eSectionTypeDWARFDebugRanges,
 155       eSectionTypeDWARFDebugRngLists,   eSectionTypeDWARFDebugStr,
 156       eSectionTypeDWARFDebugStrOffsets, eSectionTypeDWARFDebugTypes,
 157       eSectionTypeELFSymbolTable,       eSectionTypeDWARFGNUDebugAltLink,
 158   };
 159   for (SectionType section_type : g_sections) {
 160     if (SectionSP section_sp =
 161             objfile_section_list->FindSectionByType(section_type, true)) {
 162       if (SectionSP module_section_sp =
 163               module_section_list->FindSectionByType(section_type, true))
 164         module_section_list->ReplaceSection(module_section_sp->GetID(),
 165                                             section_sp);
 166       else
 167         module_section_list->AddSection(section_sp);
 168     }
 169   }
 170
 171   symbol_vendor->AddSymbolFileRepresentation(dsym_objfile_sp);
 172   return symbol_vendor;
 173 }