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