1 //===-- SymbolVendorWasm.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 "SymbolVendorWasm.h"
10 
11 #include <cstring>
12 #include <optional>
13 
14 #include "Plugins/ObjectFile/wasm/ObjectFileWasm.h"
15 #include "lldb/Core/Module.h"
16 #include "lldb/Core/ModuleSpec.h"
17 #include "lldb/Core/PluginManager.h"
18 #include "lldb/Core/Section.h"
19 #include "lldb/Host/Host.h"
20 #include "lldb/Symbol/LocateSymbolFile.h"
21 #include "lldb/Symbol/ObjectFile.h"
22 #include "lldb/Target/Target.h"
23 #include "lldb/Utility/StreamString.h"
24 #include "lldb/Utility/Timer.h"
25 
26 using namespace lldb;
27 using namespace lldb_private;
28 using namespace lldb_private::wasm;
29 
30 LLDB_PLUGIN_DEFINE(SymbolVendorWasm)
31 
32 // SymbolVendorWasm constructor
33 SymbolVendorWasm::SymbolVendorWasm(const lldb::ModuleSP &module_sp)
34     : SymbolVendor(module_sp) {}
35 
36 void SymbolVendorWasm::Initialize() {
37   PluginManager::RegisterPlugin(GetPluginNameStatic(),
38                                 GetPluginDescriptionStatic(), CreateInstance);
39 }
40 
41 void SymbolVendorWasm::Terminate() {
42   PluginManager::UnregisterPlugin(CreateInstance);
43 }
44 
45 llvm::StringRef SymbolVendorWasm::GetPluginDescriptionStatic() {
46   return "Symbol vendor for WASM that looks for dwo files that match "
47          "executables.";
48 }
49 
50 // CreateInstance
51 //
52 // Platforms can register a callback to use when creating symbol vendors to
53 // allow for complex debug information file setups, and to also allow for
54 // finding separate debug information files.
55 SymbolVendor *
56 SymbolVendorWasm::CreateInstance(const lldb::ModuleSP &module_sp,
57                                  lldb_private::Stream *feedback_strm) {
58   if (!module_sp)
59     return nullptr;
60 
61   ObjectFileWasm *obj_file =
62       llvm::dyn_cast_or_null<ObjectFileWasm>(module_sp->GetObjectFile());
63   if (!obj_file)
64     return nullptr;
65 
66   // If the main object file already contains debug info, then we are done.
67   if (obj_file->GetSectionList()->FindSectionByType(
68           lldb::eSectionTypeDWARFDebugInfo, true))
69     return nullptr;
70 
71   LLDB_SCOPED_TIMERF("SymbolVendorWasm::CreateInstance (module = %s)",
72                      module_sp->GetFileSpec().GetPath().c_str());
73 
74   ModuleSpec module_spec;
75   module_spec.GetFileSpec() = obj_file->GetFileSpec();
76   FileSystem::Instance().Resolve(module_spec.GetFileSpec());
77   module_spec.GetUUID() = obj_file->GetUUID();
78 
79   // A Wasm module may have a custom section named "external_debug_info" whose
80   // content is the absolute or relative path of the Wasm module that contains
81   // debug symbols for this module.
82   std::optional<FileSpec> symbol_file_spec =
83       obj_file->GetExternalDebugInfoFileSpec();
84   if (!symbol_file_spec)
85     return nullptr;
86   module_spec.GetSymbolFileSpec() = *symbol_file_spec;
87 
88   FileSpecList search_paths = Target::GetDefaultDebugFileSearchPaths();
89   FileSpec sym_fspec =
90       Symbols::LocateExecutableSymbolFile(module_spec, search_paths);
91   if (!sym_fspec)
92     return nullptr;
93 
94   DataBufferSP sym_file_data_sp;
95   lldb::offset_t sym_file_data_offset = 0;
96   ObjectFileSP sym_objfile_sp = ObjectFile::FindPlugin(
97       module_sp, &sym_fspec, 0, FileSystem::Instance().GetByteSize(sym_fspec),
98       sym_file_data_sp, sym_file_data_offset);
99   if (!sym_objfile_sp)
100     return nullptr;
101 
102   // This objfile is for debugging purposes.
103   sym_objfile_sp->SetType(ObjectFile::eTypeDebugInfo);
104 
105   SymbolVendorWasm *symbol_vendor = new SymbolVendorWasm(module_sp);
106 
107   // Get the module unified section list and add our debug sections to
108   // that.
109   SectionList *module_section_list = module_sp->GetSectionList();
110   SectionList *objfile_section_list = sym_objfile_sp->GetSectionList();
111 
112   if (!module_section_list || !objfile_section_list)
113     return nullptr;
114 
115   static const SectionType g_sections[] = {
116       eSectionTypeDWARFDebugAbbrev,   eSectionTypeDWARFDebugAddr,
117       eSectionTypeDWARFDebugAranges,  eSectionTypeDWARFDebugCuIndex,
118       eSectionTypeDWARFDebugFrame,    eSectionTypeDWARFDebugInfo,
119       eSectionTypeDWARFDebugLine,     eSectionTypeDWARFDebugLineStr,
120       eSectionTypeDWARFDebugLoc,      eSectionTypeDWARFDebugLocLists,
121       eSectionTypeDWARFDebugMacInfo,  eSectionTypeDWARFDebugMacro,
122       eSectionTypeDWARFDebugPubNames, eSectionTypeDWARFDebugPubTypes,
123       eSectionTypeDWARFDebugRanges,   eSectionTypeDWARFDebugRngLists,
124       eSectionTypeDWARFDebugStr,      eSectionTypeDWARFDebugStrOffsets,
125       eSectionTypeDWARFDebugTypes};
126   for (SectionType section_type : g_sections) {
127     if (SectionSP section_sp =
128             objfile_section_list->FindSectionByType(section_type, true)) {
129       if (SectionSP module_section_sp =
130               module_section_list->FindSectionByType(section_type, true))
131         module_section_list->ReplaceSection(module_section_sp->GetID(),
132                                             section_sp);
133       else
134         module_section_list->AddSection(section_sp);
135     }
136   }
137 
138   symbol_vendor->AddSymbolFileRepresentation(sym_objfile_sp);
139   return symbol_vendor;
140 }
141