1 //===-- llvm-dwp.cpp - Split DWARF merging tool for llvm ------------------===//
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 // A utility for merging DWARF 5 Split DWARF .dwo files into .dwp (DWARF
10 // package files).
11 //
12 //===----------------------------------------------------------------------===//
13 #include "llvm/DWP/DWP.h"
14 #include "llvm/DWP/DWPError.h"
15 #include "llvm/DWP/DWPStringPool.h"
16 #include "llvm/MC/MCAsmBackend.h"
17 #include "llvm/MC/MCAsmInfo.h"
18 #include "llvm/MC/MCCodeEmitter.h"
19 #include "llvm/MC/MCContext.h"
20 #include "llvm/MC/MCInstrInfo.h"
21 #include "llvm/MC/MCObjectWriter.h"
22 #include "llvm/MC/MCTargetOptionsCommandFlags.h"
23 #include "llvm/Support/CommandLine.h"
24 #include "llvm/Support/FileSystem.h"
25 #include "llvm/Support/InitLLVM.h"
26 #include "llvm/Support/TargetRegistry.h"
27 #include "llvm/Support/TargetSelect.h"
28 #include "llvm/Support/ToolOutputFile.h"
29 
30 using namespace llvm;
31 using namespace llvm::object;
32 
33 static mc::RegisterMCTargetOptionsFlags MCTargetOptionsFlags;
34 
35 cl::OptionCategory DwpCategory("Specific Options");
36 static cl::list<std::string> InputFiles(cl::Positional, cl::ZeroOrMore,
37                                         cl::desc("<input files>"),
38                                         cl::cat(DwpCategory));
39 
40 static cl::list<std::string> ExecFilenames(
41     "e", cl::ZeroOrMore,
42     cl::desc("Specify the executable/library files to get the list of *.dwo from"),
43     cl::value_desc("filename"), cl::cat(DwpCategory));
44 
45 static cl::opt<std::string> OutputFilename(cl::Required, "o",
46                                            cl::desc("Specify the output file."),
47                                            cl::value_desc("filename"),
48                                            cl::cat(DwpCategory));
49 
50 static Expected<SmallVector<std::string, 16>>
getDWOFilenames(StringRef ExecFilename)51 getDWOFilenames(StringRef ExecFilename) {
52   auto ErrOrObj = object::ObjectFile::createObjectFile(ExecFilename);
53   if (!ErrOrObj)
54     return ErrOrObj.takeError();
55 
56   const ObjectFile &Obj = *ErrOrObj.get().getBinary();
57   std::unique_ptr<DWARFContext> DWARFCtx = DWARFContext::create(Obj);
58 
59   SmallVector<std::string, 16> DWOPaths;
60   for (const auto &CU : DWARFCtx->compile_units()) {
61     const DWARFDie &Die = CU->getUnitDIE();
62     std::string DWOName = dwarf::toString(
63         Die.find({dwarf::DW_AT_dwo_name, dwarf::DW_AT_GNU_dwo_name}), "");
64     if (DWOName.empty())
65       continue;
66     std::string DWOCompDir =
67         dwarf::toString(Die.find(dwarf::DW_AT_comp_dir), "");
68     if (!DWOCompDir.empty()) {
69       SmallString<16> DWOPath(std::move(DWOName));
70       sys::fs::make_absolute(DWOCompDir, DWOPath);
71       DWOPaths.emplace_back(DWOPath.data(), DWOPath.size());
72     } else {
73       DWOPaths.push_back(std::move(DWOName));
74     }
75   }
76   return std::move(DWOPaths);
77 }
78 
error(const Twine & Error,const Twine & Context)79 static int error(const Twine &Error, const Twine &Context) {
80   errs() << Twine("while processing ") + Context + ":\n";
81   errs() << Twine("error: ") + Error + "\n";
82   return 1;
83 }
84 
readTargetTriple(StringRef FileName)85 static Expected<Triple> readTargetTriple(StringRef FileName) {
86   auto ErrOrObj = object::ObjectFile::createObjectFile(FileName);
87   if (!ErrOrObj)
88     return ErrOrObj.takeError();
89 
90   return ErrOrObj->getBinary()->makeTriple();
91 }
92 
main(int argc,char ** argv)93 int main(int argc, char **argv) {
94   InitLLVM X(argc, argv);
95 
96   cl::HideUnrelatedOptions({&DwpCategory, &getColorCategory()});
97   cl::ParseCommandLineOptions(argc, argv, "merge split dwarf (.dwo) files\n");
98 
99   llvm::InitializeAllTargetInfos();
100   llvm::InitializeAllTargetMCs();
101   llvm::InitializeAllTargets();
102   llvm::InitializeAllAsmPrinters();
103 
104   std::vector<std::string> DWOFilenames = InputFiles;
105   for (const auto &ExecFilename : ExecFilenames) {
106     auto DWOs = getDWOFilenames(ExecFilename);
107     if (!DWOs) {
108       logAllUnhandledErrors(DWOs.takeError(), WithColor::error());
109       return 1;
110     }
111     DWOFilenames.insert(DWOFilenames.end(),
112                         std::make_move_iterator(DWOs->begin()),
113                         std::make_move_iterator(DWOs->end()));
114   }
115 
116   if (DWOFilenames.empty())
117     return 0;
118 
119   std::string ErrorStr;
120   StringRef Context = "dwarf streamer init";
121 
122   auto ErrOrTriple = readTargetTriple(DWOFilenames.front());
123   if (!ErrOrTriple) {
124     logAllUnhandledErrors(ErrOrTriple.takeError(), WithColor::error());
125     return 1;
126   }
127 
128   // Get the target.
129   const Target *TheTarget =
130       TargetRegistry::lookupTarget("", *ErrOrTriple, ErrorStr);
131   if (!TheTarget)
132     return error(ErrorStr, Context);
133   std::string TripleName = ErrOrTriple->getTriple();
134 
135   // Create all the MC Objects.
136   std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TripleName));
137   if (!MRI)
138     return error(Twine("no register info for target ") + TripleName, Context);
139 
140   MCTargetOptions MCOptions = llvm::mc::InitMCTargetOptionsFromFlags();
141   std::unique_ptr<MCAsmInfo> MAI(
142       TheTarget->createMCAsmInfo(*MRI, TripleName, MCOptions));
143   if (!MAI)
144     return error("no asm info for target " + TripleName, Context);
145 
146   std::unique_ptr<MCSubtargetInfo> MSTI(
147       TheTarget->createMCSubtargetInfo(TripleName, "", ""));
148   if (!MSTI)
149     return error("no subtarget info for target " + TripleName, Context);
150 
151   MCContext MC(*ErrOrTriple, MAI.get(), MRI.get(), MSTI.get());
152   std::unique_ptr<MCObjectFileInfo> MOFI(
153       TheTarget->createMCObjectFileInfo(MC, /*PIC=*/false));
154   MC.setObjectFileInfo(MOFI.get());
155 
156   MCTargetOptions Options;
157   auto MAB = TheTarget->createMCAsmBackend(*MSTI, *MRI, Options);
158   if (!MAB)
159     return error("no asm backend for target " + TripleName, Context);
160 
161   std::unique_ptr<MCInstrInfo> MII(TheTarget->createMCInstrInfo());
162   if (!MII)
163     return error("no instr info info for target " + TripleName, Context);
164 
165   MCCodeEmitter *MCE = TheTarget->createMCCodeEmitter(*MII, *MRI, MC);
166   if (!MCE)
167     return error("no code emitter for target " + TripleName, Context);
168 
169   // Create the output file.
170   std::error_code EC;
171   ToolOutputFile OutFile(OutputFilename, EC, sys::fs::OF_None);
172   Optional<buffer_ostream> BOS;
173   raw_pwrite_stream *OS;
174   if (EC)
175     return error(Twine(OutputFilename) + ": " + EC.message(), Context);
176   if (OutFile.os().supportsSeeking()) {
177     OS = &OutFile.os();
178   } else {
179     BOS.emplace(OutFile.os());
180     OS = BOS.getPointer();
181   }
182 
183   std::unique_ptr<MCStreamer> MS(TheTarget->createMCObjectStreamer(
184       *ErrOrTriple, MC, std::unique_ptr<MCAsmBackend>(MAB),
185       MAB->createObjectWriter(*OS), std::unique_ptr<MCCodeEmitter>(MCE), *MSTI,
186       MCOptions.MCRelaxAll, MCOptions.MCIncrementalLinkerCompatible,
187       /*DWARFMustBeAtTheEnd*/ false));
188   if (!MS)
189     return error("no object streamer for target " + TripleName, Context);
190 
191   if (auto Err = write(*MS, DWOFilenames)) {
192     logAllUnhandledErrors(std::move(Err), WithColor::error());
193     return 1;
194   }
195 
196   MS->Finish();
197   OutFile.keep();
198   return 0;
199 }
200