xref: /llvm-project/llvm/lib/Object/IRObjectFile.cpp (revision cc1aa05350d37ef1b71edc37747c4992bc183fa1)
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/ADT/STLExtras.h"
17 #include "llvm/Bitcode/ReaderWriter.h"
18 #include "llvm/IR/GVMaterializer.h"
19 #include "llvm/IR/LLVMContext.h"
20 #include "llvm/IR/Mangler.h"
21 #include "llvm/IR/Module.h"
22 #include "llvm/MC/MCAsmInfo.h"
23 #include "llvm/MC/MCContext.h"
24 #include "llvm/MC/MCInstrInfo.h"
25 #include "llvm/MC/MCObjectFileInfo.h"
26 #include "llvm/MC/MCParser/MCAsmParser.h"
27 #include "llvm/MC/MCParser/MCTargetAsmParser.h"
28 #include "llvm/MC/MCRegisterInfo.h"
29 #include "llvm/MC/MCSubtargetInfo.h"
30 #include "llvm/Object/ObjectFile.h"
31 #include "llvm/Support/MemoryBuffer.h"
32 #include "llvm/Support/SourceMgr.h"
33 #include "llvm/Support/TargetRegistry.h"
34 #include "llvm/Support/raw_ostream.h"
35 using namespace llvm;
36 using namespace object;
37 
38 IRObjectFile::IRObjectFile(MemoryBufferRef Object, std::unique_ptr<Module> Mod)
39     : SymbolicFile(Binary::ID_IR, Object), M(std::move(Mod)) {
40   Mang.reset(new Mangler());
41   CollectAsmUndefinedRefs(Triple(M->getTargetTriple()), M->getModuleInlineAsm(),
42                           [this](StringRef Name, BasicSymbolRef::Flags Flags) {
43                             AsmSymbols.emplace_back(Name, std::move(Flags));
44                           });
45 }
46 
47 // Parse inline ASM and collect the list of symbols that are not defined in
48 // the current module. This is inspired from IRObjectFile.
49 void IRObjectFile::CollectAsmUndefinedRefs(
50     const Triple &TT, StringRef InlineAsm,
51     function_ref<void(StringRef, BasicSymbolRef::Flags)> AsmUndefinedRefs) {
52   if (InlineAsm.empty())
53     return;
54 
55   std::string Err;
56   const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
57   if (!T)
58     return;
59 
60   std::unique_ptr<MCRegisterInfo> MRI(T->createMCRegInfo(TT.str()));
61   if (!MRI)
62     return;
63 
64   std::unique_ptr<MCAsmInfo> MAI(T->createMCAsmInfo(*MRI, TT.str()));
65   if (!MAI)
66     return;
67 
68   std::unique_ptr<MCSubtargetInfo> STI(
69       T->createMCSubtargetInfo(TT.str(), "", ""));
70   if (!STI)
71     return;
72 
73   std::unique_ptr<MCInstrInfo> MCII(T->createMCInstrInfo());
74   if (!MCII)
75     return;
76 
77   MCObjectFileInfo MOFI;
78   MCContext MCCtx(MAI.get(), MRI.get(), &MOFI);
79   MOFI.InitMCObjectFileInfo(TT, /*PIC*/ false, CodeModel::Default, MCCtx);
80   std::unique_ptr<RecordStreamer> Streamer(new RecordStreamer(MCCtx));
81   T->createNullTargetStreamer(*Streamer);
82 
83   std::unique_ptr<MemoryBuffer> Buffer(MemoryBuffer::getMemBuffer(InlineAsm));
84   SourceMgr SrcMgr;
85   SrcMgr.AddNewSourceBuffer(std::move(Buffer), SMLoc());
86   std::unique_ptr<MCAsmParser> Parser(
87       createMCAsmParser(SrcMgr, MCCtx, *Streamer, *MAI));
88 
89   MCTargetOptions MCOptions;
90   std::unique_ptr<MCTargetAsmParser> TAP(
91       T->createMCAsmParser(*STI, *Parser, *MCII, MCOptions));
92   if (!TAP)
93     return;
94 
95   Parser->setTargetParser(*TAP);
96   if (Parser->Run(false))
97     return;
98 
99   for (auto &KV : *Streamer) {
100     StringRef Key = KV.first();
101     RecordStreamer::State Value = KV.second;
102     uint32_t Res = BasicSymbolRef::SF_None;
103     switch (Value) {
104     case RecordStreamer::NeverSeen:
105       llvm_unreachable("NeverSeen should have been replaced earlier");
106     case RecordStreamer::DefinedGlobal:
107       Res |= BasicSymbolRef::SF_Global;
108       break;
109     case RecordStreamer::Defined:
110       break;
111     case RecordStreamer::Global:
112     case RecordStreamer::Used:
113       Res |= BasicSymbolRef::SF_Undefined;
114       Res |= BasicSymbolRef::SF_Global;
115       break;
116     case RecordStreamer::DefinedWeak:
117       Res |= BasicSymbolRef::SF_Weak;
118       Res |= BasicSymbolRef::SF_Global;
119       break;
120     case RecordStreamer::UndefinedWeak:
121       Res |= BasicSymbolRef::SF_Weak;
122       Res |= BasicSymbolRef::SF_Undefined;
123     }
124     AsmUndefinedRefs(Key, BasicSymbolRef::Flags(Res));
125   }
126 }
127 
128 IRObjectFile::~IRObjectFile() {
129  }
130 
131 static GlobalValue *getGV(DataRefImpl &Symb) {
132   if ((Symb.p & 3) == 3)
133     return nullptr;
134 
135   return reinterpret_cast<GlobalValue*>(Symb.p & ~uintptr_t(3));
136 }
137 
138 static uintptr_t skipEmpty(Module::const_alias_iterator I, const Module &M) {
139   if (I == M.alias_end())
140     return 3;
141   const GlobalValue *GV = &*I;
142   return reinterpret_cast<uintptr_t>(GV) | 2;
143 }
144 
145 static uintptr_t skipEmpty(Module::const_global_iterator I, const Module &M) {
146   if (I == M.global_end())
147     return skipEmpty(M.alias_begin(), M);
148   const GlobalValue *GV = &*I;
149   return reinterpret_cast<uintptr_t>(GV) | 1;
150 }
151 
152 static uintptr_t skipEmpty(Module::const_iterator I, const Module &M) {
153   if (I == M.end())
154     return skipEmpty(M.global_begin(), M);
155   const GlobalValue *GV = &*I;
156   return reinterpret_cast<uintptr_t>(GV) | 0;
157 }
158 
159 static unsigned getAsmSymIndex(DataRefImpl Symb) {
160   assert((Symb.p & uintptr_t(3)) == 3);
161   uintptr_t Index = Symb.p & ~uintptr_t(3);
162   Index >>= 2;
163   return Index;
164 }
165 
166 void IRObjectFile::moveSymbolNext(DataRefImpl &Symb) const {
167   const GlobalValue *GV = getGV(Symb);
168   uintptr_t Res;
169 
170   switch (Symb.p & 3) {
171   case 0: {
172     Module::const_iterator Iter(static_cast<const Function*>(GV));
173     ++Iter;
174     Res = skipEmpty(Iter, *M);
175     break;
176   }
177   case 1: {
178     Module::const_global_iterator Iter(static_cast<const GlobalVariable*>(GV));
179     ++Iter;
180     Res = skipEmpty(Iter, *M);
181     break;
182   }
183   case 2: {
184     Module::const_alias_iterator Iter(static_cast<const GlobalAlias*>(GV));
185     ++Iter;
186     Res = skipEmpty(Iter, *M);
187     break;
188   }
189   case 3: {
190     unsigned Index = getAsmSymIndex(Symb);
191     assert(Index < AsmSymbols.size());
192     ++Index;
193     Res = (Index << 2) | 3;
194     break;
195   }
196   default:
197     llvm_unreachable("unreachable case");
198   }
199 
200   Symb.p = Res;
201 }
202 
203 std::error_code IRObjectFile::printSymbolName(raw_ostream &OS,
204                                               DataRefImpl Symb) const {
205   const GlobalValue *GV = getGV(Symb);
206   if (!GV) {
207     unsigned Index = getAsmSymIndex(Symb);
208     assert(Index <= AsmSymbols.size());
209     OS << AsmSymbols[Index].first;
210     return std::error_code();
211   }
212 
213   if (GV->hasDLLImportStorageClass())
214     OS << "__imp_";
215 
216   if (Mang)
217     Mang->getNameWithPrefix(OS, GV, false);
218   else
219     OS << GV->getName();
220 
221   return std::error_code();
222 }
223 
224 uint32_t IRObjectFile::getSymbolFlags(DataRefImpl Symb) const {
225   const GlobalValue *GV = getGV(Symb);
226 
227   if (!GV) {
228     unsigned Index = getAsmSymIndex(Symb);
229     assert(Index <= AsmSymbols.size());
230     return AsmSymbols[Index].second;
231   }
232 
233   uint32_t Res = BasicSymbolRef::SF_None;
234   if (GV->isDeclarationForLinker())
235     Res |= BasicSymbolRef::SF_Undefined;
236   else if (GV->hasHiddenVisibility() && !GV->hasLocalLinkage())
237     Res |= BasicSymbolRef::SF_Hidden;
238   if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV)) {
239     if (GVar->isConstant())
240       Res |= BasicSymbolRef::SF_Const;
241   }
242   if (GV->hasPrivateLinkage())
243     Res |= BasicSymbolRef::SF_FormatSpecific;
244   if (!GV->hasLocalLinkage())
245     Res |= BasicSymbolRef::SF_Global;
246   if (GV->hasCommonLinkage())
247     Res |= BasicSymbolRef::SF_Common;
248   if (GV->hasLinkOnceLinkage() || GV->hasWeakLinkage() ||
249       GV->hasExternalWeakLinkage())
250     Res |= BasicSymbolRef::SF_Weak;
251 
252   if (GV->getName().startswith("llvm."))
253     Res |= BasicSymbolRef::SF_FormatSpecific;
254   else if (auto *Var = dyn_cast<GlobalVariable>(GV)) {
255     if (Var->getSection() == "llvm.metadata")
256       Res |= BasicSymbolRef::SF_FormatSpecific;
257   }
258 
259   return Res;
260 }
261 
262 GlobalValue *IRObjectFile::getSymbolGV(DataRefImpl Symb) { return getGV(Symb); }
263 
264 std::unique_ptr<Module> IRObjectFile::takeModule() { return std::move(M); }
265 
266 basic_symbol_iterator IRObjectFile::symbol_begin_impl() const {
267   Module::const_iterator I = M->begin();
268   DataRefImpl Ret;
269   Ret.p = skipEmpty(I, *M);
270   return basic_symbol_iterator(BasicSymbolRef(Ret, this));
271 }
272 
273 basic_symbol_iterator IRObjectFile::symbol_end_impl() const {
274   DataRefImpl Ret;
275   uint64_t NumAsm = AsmSymbols.size();
276   NumAsm <<= 2;
277   Ret.p = 3 | NumAsm;
278   return basic_symbol_iterator(BasicSymbolRef(Ret, this));
279 }
280 
281 ErrorOr<MemoryBufferRef> IRObjectFile::findBitcodeInObject(const ObjectFile &Obj) {
282   for (const SectionRef &Sec : Obj.sections()) {
283     if (Sec.isBitcode()) {
284       StringRef SecContents;
285       if (std::error_code EC = Sec.getContents(SecContents))
286         return EC;
287       return MemoryBufferRef(SecContents, Obj.getFileName());
288     }
289   }
290 
291   return object_error::bitcode_section_not_found;
292 }
293 
294 ErrorOr<MemoryBufferRef> IRObjectFile::findBitcodeInMemBuffer(MemoryBufferRef Object) {
295   sys::fs::file_magic Type = sys::fs::identify_magic(Object.getBuffer());
296   switch (Type) {
297   case sys::fs::file_magic::bitcode:
298     return Object;
299   case sys::fs::file_magic::elf_relocatable:
300   case sys::fs::file_magic::macho_object:
301   case sys::fs::file_magic::coff_object: {
302     Expected<std::unique_ptr<ObjectFile>> ObjFile =
303         ObjectFile::createObjectFile(Object, Type);
304     if (!ObjFile)
305       return errorToErrorCode(ObjFile.takeError());
306     return findBitcodeInObject(*ObjFile->get());
307   }
308   default:
309     return object_error::invalid_file_type;
310   }
311 }
312 
313 ErrorOr<std::unique_ptr<IRObjectFile>>
314 llvm::object::IRObjectFile::create(MemoryBufferRef Object,
315                                    LLVMContext &Context) {
316   ErrorOr<MemoryBufferRef> BCOrErr = findBitcodeInMemBuffer(Object);
317   if (!BCOrErr)
318     return BCOrErr.getError();
319 
320   std::unique_ptr<MemoryBuffer> Buff =
321       MemoryBuffer::getMemBuffer(BCOrErr.get(), false);
322 
323   ErrorOr<std::unique_ptr<Module>> MOrErr =
324       getLazyBitcodeModule(std::move(Buff), Context,
325                            /*ShouldLazyLoadMetadata*/ true);
326   if (std::error_code EC = MOrErr.getError())
327     return EC;
328 
329   std::unique_ptr<Module> &M = MOrErr.get();
330   return llvm::make_unique<IRObjectFile>(BCOrErr.get(), std::move(M));
331 }
332