1 //===- IRObjectFile.cpp - IR object file implementation ---------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // Part of the IRObjectFile class implementation.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/Object/IRObjectFile.h"
15 #include "RecordStreamer.h"
16 #include "llvm/Bitcode/ReaderWriter.h"
17 #include "llvm/IR/GVMaterializer.h"
18 #include "llvm/IR/LLVMContext.h"
19 #include "llvm/IR/Mangler.h"
20 #include "llvm/IR/Module.h"
21 #include "llvm/MC/MCAsmInfo.h"
22 #include "llvm/MC/MCContext.h"
23 #include "llvm/MC/MCInstrInfo.h"
24 #include "llvm/MC/MCObjectFileInfo.h"
25 #include "llvm/MC/MCParser/MCAsmParser.h"
26 #include "llvm/MC/MCRegisterInfo.h"
27 #include "llvm/MC/MCTargetAsmParser.h"
28 #include "llvm/Object/ObjectFile.h"
29 #include "llvm/Support/MemoryBuffer.h"
30 #include "llvm/Support/SourceMgr.h"
31 #include "llvm/Support/TargetRegistry.h"
32 #include "llvm/Support/raw_ostream.h"
33 using namespace llvm;
34 using namespace object;
35 
36 IRObjectFile::IRObjectFile(MemoryBufferRef Object, std::unique_ptr<Module> Mod)
37     : SymbolicFile(Binary::ID_IR, Object), M(std::move(Mod)) {
38   // If we have a DataLayout, setup a mangler.
39   const DataLayout *DL = M->getDataLayout();
40   if (!DL)
41     return;
42 
43   Mang.reset(new Mangler(DL));
44 
45   const std::string &InlineAsm = M->getModuleInlineAsm();
46   if (InlineAsm.empty())
47     return;
48 
49   StringRef Triple = M->getTargetTriple();
50   std::string Err;
51   const Target *T = TargetRegistry::lookupTarget(Triple, Err);
52   if (!T)
53     return;
54 
55   std::unique_ptr<MCRegisterInfo> MRI(T->createMCRegInfo(Triple));
56   if (!MRI)
57     return;
58 
59   std::unique_ptr<MCAsmInfo> MAI(T->createMCAsmInfo(*MRI, Triple));
60   if (!MAI)
61     return;
62 
63   std::unique_ptr<MCSubtargetInfo> STI(
64       T->createMCSubtargetInfo(Triple, "", ""));
65   if (!STI)
66     return;
67 
68   std::unique_ptr<MCInstrInfo> MCII(T->createMCInstrInfo());
69   if (!MCII)
70     return;
71 
72   MCObjectFileInfo MOFI;
73   MCContext MCCtx(MAI.get(), MRI.get(), &MOFI);
74   MOFI.InitMCObjectFileInfo(Triple, Reloc::Default, CodeModel::Default, MCCtx);
75   std::unique_ptr<RecordStreamer> Streamer(new RecordStreamer(MCCtx));
76   T->createNullTargetStreamer(*Streamer);
77 
78   std::unique_ptr<MemoryBuffer> Buffer(MemoryBuffer::getMemBuffer(InlineAsm));
79   SourceMgr SrcMgr;
80   SrcMgr.AddNewSourceBuffer(std::move(Buffer), SMLoc());
81   std::unique_ptr<MCAsmParser> Parser(
82       createMCAsmParser(SrcMgr, MCCtx, *Streamer, *MAI));
83 
84   MCTargetOptions MCOptions;
85   std::unique_ptr<MCTargetAsmParser> TAP(
86       T->createMCAsmParser(*STI, *Parser, *MCII, MCOptions));
87   if (!TAP)
88     return;
89 
90   Parser->setTargetParser(*TAP);
91   if (Parser->Run(false))
92     return;
93 
94   for (auto &KV : *Streamer) {
95     StringRef Key = KV.first();
96     RecordStreamer::State Value = KV.second;
97     uint32_t Res = BasicSymbolRef::SF_None;
98     switch (Value) {
99     case RecordStreamer::NeverSeen:
100       llvm_unreachable("foo");
101     case RecordStreamer::DefinedGlobal:
102       Res |= BasicSymbolRef::SF_Global;
103       break;
104     case RecordStreamer::Defined:
105       break;
106     case RecordStreamer::Global:
107     case RecordStreamer::Used:
108       Res |= BasicSymbolRef::SF_Undefined;
109       Res |= BasicSymbolRef::SF_Global;
110       break;
111     }
112     AsmSymbols.push_back(
113         std::make_pair<std::string, uint32_t>(Key, std::move(Res)));
114   }
115 }
116 
117 IRObjectFile::~IRObjectFile() {
118  }
119 
120 static GlobalValue *getGV(DataRefImpl &Symb) {
121   if ((Symb.p & 3) == 3)
122     return nullptr;
123 
124   return reinterpret_cast<GlobalValue*>(Symb.p & ~uintptr_t(3));
125 }
126 
127 static uintptr_t skipEmpty(Module::const_alias_iterator I, const Module &M) {
128   if (I == M.alias_end())
129     return 3;
130   const GlobalValue *GV = &*I;
131   return reinterpret_cast<uintptr_t>(GV) | 2;
132 }
133 
134 static uintptr_t skipEmpty(Module::const_global_iterator I, const Module &M) {
135   if (I == M.global_end())
136     return skipEmpty(M.alias_begin(), M);
137   const GlobalValue *GV = &*I;
138   return reinterpret_cast<uintptr_t>(GV) | 1;
139 }
140 
141 static uintptr_t skipEmpty(Module::const_iterator I, const Module &M) {
142   if (I == M.end())
143     return skipEmpty(M.global_begin(), M);
144   const GlobalValue *GV = &*I;
145   return reinterpret_cast<uintptr_t>(GV) | 0;
146 }
147 
148 static unsigned getAsmSymIndex(DataRefImpl Symb) {
149   assert((Symb.p & uintptr_t(3)) == 3);
150   uintptr_t Index = Symb.p & ~uintptr_t(3);
151   Index >>= 2;
152   return Index;
153 }
154 
155 void IRObjectFile::moveSymbolNext(DataRefImpl &Symb) const {
156   const GlobalValue *GV = getGV(Symb);
157   uintptr_t Res;
158 
159   switch (Symb.p & 3) {
160   case 0: {
161     Module::const_iterator Iter(static_cast<const Function*>(GV));
162     ++Iter;
163     Res = skipEmpty(Iter, *M);
164     break;
165   }
166   case 1: {
167     Module::const_global_iterator Iter(static_cast<const GlobalVariable*>(GV));
168     ++Iter;
169     Res = skipEmpty(Iter, *M);
170     break;
171   }
172   case 2: {
173     Module::const_alias_iterator Iter(static_cast<const GlobalAlias*>(GV));
174     ++Iter;
175     Res = skipEmpty(Iter, *M);
176     break;
177   }
178   case 3: {
179     unsigned Index = getAsmSymIndex(Symb);
180     assert(Index < AsmSymbols.size());
181     ++Index;
182     Res = (Index << 2) | 3;
183     break;
184   }
185   default:
186     llvm_unreachable("unreachable case");
187   }
188 
189   Symb.p = Res;
190 }
191 
192 std::error_code IRObjectFile::printSymbolName(raw_ostream &OS,
193                                               DataRefImpl Symb) const {
194   const GlobalValue *GV = getGV(Symb);
195   if (!GV) {
196     unsigned Index = getAsmSymIndex(Symb);
197     assert(Index <= AsmSymbols.size());
198     OS << AsmSymbols[Index].first;
199     return object_error::success;;
200   }
201 
202   if (Mang)
203     Mang->getNameWithPrefix(OS, GV, false);
204   else
205     OS << GV->getName();
206 
207   return object_error::success;
208 }
209 
210 uint32_t IRObjectFile::getSymbolFlags(DataRefImpl Symb) const {
211   const GlobalValue *GV = getGV(Symb);
212 
213   if (!GV) {
214     unsigned Index = getAsmSymIndex(Symb);
215     assert(Index <= AsmSymbols.size());
216     return AsmSymbols[Index].second;
217   }
218 
219   uint32_t Res = BasicSymbolRef::SF_None;
220   if (GV->isDeclarationForLinker())
221     Res |= BasicSymbolRef::SF_Undefined;
222   if (GV->hasPrivateLinkage())
223     Res |= BasicSymbolRef::SF_FormatSpecific;
224   if (!GV->hasLocalLinkage())
225     Res |= BasicSymbolRef::SF_Global;
226   if (GV->hasCommonLinkage())
227     Res |= BasicSymbolRef::SF_Common;
228   if (GV->hasLinkOnceLinkage() || GV->hasWeakLinkage())
229     Res |= BasicSymbolRef::SF_Weak;
230 
231   if (GV->getName().startswith("llvm."))
232     Res |= BasicSymbolRef::SF_FormatSpecific;
233   else if (auto *Var = dyn_cast<GlobalVariable>(GV)) {
234     if (Var->getSection() == StringRef("llvm.metadata"))
235       Res |= BasicSymbolRef::SF_FormatSpecific;
236   }
237 
238   return Res;
239 }
240 
241 GlobalValue *IRObjectFile::getSymbolGV(DataRefImpl Symb) { return getGV(Symb); }
242 
243 std::unique_ptr<Module> IRObjectFile::takeModule() { return std::move(M); }
244 
245 basic_symbol_iterator IRObjectFile::symbol_begin_impl() const {
246   Module::const_iterator I = M->begin();
247   DataRefImpl Ret;
248   Ret.p = skipEmpty(I, *M);
249   return basic_symbol_iterator(BasicSymbolRef(Ret, this));
250 }
251 
252 basic_symbol_iterator IRObjectFile::symbol_end_impl() const {
253   DataRefImpl Ret;
254   uint64_t NumAsm = AsmSymbols.size();
255   NumAsm <<= 2;
256   Ret.p = 3 | NumAsm;
257   return basic_symbol_iterator(BasicSymbolRef(Ret, this));
258 }
259 
260 ErrorOr<MemoryBufferRef> IRObjectFile::findBitcodeInObject(const ObjectFile &Obj) {
261   for (const SectionRef &Sec : Obj.sections()) {
262     StringRef SecName;
263     if (std::error_code EC = Sec.getName(SecName))
264       return EC;
265     if (SecName == ".llvmbc") {
266       StringRef SecContents;
267       if (std::error_code EC = Sec.getContents(SecContents))
268         return EC;
269       return MemoryBufferRef(SecContents, Obj.getFileName());
270     }
271   }
272 
273   return object_error::bitcode_section_not_found;
274 }
275 
276 ErrorOr<MemoryBufferRef> IRObjectFile::findBitcodeInMemBuffer(MemoryBufferRef Object) {
277   sys::fs::file_magic Type = sys::fs::identify_magic(Object.getBuffer());
278   switch (Type) {
279   case sys::fs::file_magic::bitcode:
280     return Object;
281   case sys::fs::file_magic::elf_relocatable:
282   case sys::fs::file_magic::macho_object:
283   case sys::fs::file_magic::coff_object: {
284     ErrorOr<std::unique_ptr<ObjectFile>> ObjFile =
285         ObjectFile::createObjectFile(Object, Type);
286     if (!ObjFile)
287       return ObjFile.getError();
288     return findBitcodeInObject(*ObjFile->get());
289   }
290   default:
291     return object_error::invalid_file_type;
292   }
293 }
294 
295 ErrorOr<std::unique_ptr<IRObjectFile>>
296 llvm::object::IRObjectFile::create(MemoryBufferRef Object,
297                                    LLVMContext &Context) {
298   ErrorOr<MemoryBufferRef> BCOrErr = findBitcodeInMemBuffer(Object);
299   if (!BCOrErr)
300     return BCOrErr.getError();
301 
302   std::unique_ptr<MemoryBuffer> Buff(
303       MemoryBuffer::getMemBuffer(BCOrErr.get(), false));
304 
305   ErrorOr<Module *> MOrErr = getLazyBitcodeModule(std::move(Buff), Context);
306   if (std::error_code EC = MOrErr.getError())
307     return EC;
308 
309   std::unique_ptr<Module> M(MOrErr.get());
310   return llvm::make_unique<IRObjectFile>(Object, std::move(M));
311 }
312