1 //===- ModuleSymbolTable.cpp - symbol table for in-memory IR --------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This class represents a symbol table built from in-memory IR. It provides
11 // access to GlobalValues and should only be used if such access is required
12 // (e.g. in the LTO implementation).
14 //===----------------------------------------------------------------------===//
16 #include "llvm/Object/ModuleSymbolTable.h"
17 #include "RecordStreamer.h"
18 #include "llvm/ADT/STLExtras.h"
19 #include "llvm/ADT/SmallString.h"
20 #include "llvm/ADT/StringMap.h"
21 #include "llvm/ADT/StringRef.h"
22 #include "llvm/ADT/Triple.h"
23 #include "llvm/IR/Function.h"
24 #include "llvm/IR/GlobalAlias.h"
25 #include "llvm/IR/GlobalValue.h"
26 #include "llvm/IR/GlobalVariable.h"
27 #include "llvm/IR/Mangler.h"
28 #include "llvm/IR/Module.h"
29 #include "llvm/MC/MCAsmInfo.h"
30 #include "llvm/MC/MCContext.h"
31 #include "llvm/MC/MCDirectives.h"
32 #include "llvm/MC/MCInstrInfo.h"
33 #include "llvm/MC/MCObjectFileInfo.h"
34 #include "llvm/MC/MCParser/MCAsmParser.h"
35 #include "llvm/MC/MCParser/MCTargetAsmParser.h"
36 #include "llvm/MC/MCRegisterInfo.h"
37 #include "llvm/MC/MCSubtargetInfo.h"
38 #include "llvm/MC/MCSymbol.h"
39 #include "llvm/MC/MCTargetOptions.h"
40 #include "llvm/Object/SymbolicFile.h"
41 #include "llvm/Support/Casting.h"
42 #include "llvm/Support/CodeGen.h"
43 #include "llvm/Support/ErrorHandling.h"
44 #include "llvm/Support/MemoryBuffer.h"
45 #include "llvm/Support/SMLoc.h"
46 #include "llvm/Support/SourceMgr.h"
47 #include "llvm/Support/TargetRegistry.h"
48 #include "llvm/Support/raw_ostream.h"
56 using namespace object;
58 void ModuleSymbolTable::addModule(Module *M) {
60 assert(FirstMod->getTargetTriple() == M->getTargetTriple());
64 for (GlobalValue &GV : M->global_values())
65 SymTab.push_back(&GV);
67 CollectAsmSymbols(*M, [this](StringRef Name, BasicSymbolRef::Flags Flags) {
68 SymTab.push_back(new (AsmSymbols.Allocate()) AsmSymbol(Name, Flags));
72 // Ensure ELF .symver aliases get the same binding as the defined symbol
74 static void handleSymverAliases(const Module &M, RecordStreamer &Streamer) {
75 if (Streamer.symverAliases().empty())
78 // The name in the assembler will be mangled, but the name in the IR
79 // might not, so we first compute a mapping from mangled name to GV.
81 SmallString<64> MangledName;
82 StringMap<const GlobalValue *> MangledNameMap;
83 auto GetMangledName = [&](const GlobalValue &GV) {
88 MangledName.reserve(GV.getName().size() + 1);
89 Mang.getNameWithPrefix(MangledName, &GV, /*CannotUsePrivateLabel=*/false);
90 MangledNameMap[MangledName] = &GV;
92 for (const Function &F : M)
94 for (const GlobalVariable &GV : M.globals())
96 for (const GlobalAlias &GA : M.aliases())
99 // Walk all the recorded .symver aliases, and set up the binding
101 for (auto &Symver : Streamer.symverAliases()) {
102 const MCSymbol *Aliasee = Symver.first;
103 MCSymbolAttr Attr = MCSA_Invalid;
105 // First check if the aliasee binding was recorded in the asm.
106 RecordStreamer::State state = Streamer.getSymbolState(Aliasee);
108 case RecordStreamer::Global:
109 case RecordStreamer::DefinedGlobal:
112 case RecordStreamer::UndefinedWeak:
113 case RecordStreamer::DefinedWeak:
120 // If we don't have a symbol attribute from assembly, then check if
121 // the aliasee was defined in the IR.
122 if (Attr == MCSA_Invalid) {
123 const auto *GV = M.getNamedValue(Aliasee->getName());
125 auto MI = MangledNameMap.find(Aliasee->getName());
126 if (MI != MangledNameMap.end())
131 if (GV->hasExternalLinkage())
133 else if (GV->hasLocalLinkage())
135 else if (GV->isWeakForLinker())
138 if (Attr == MCSA_Invalid)
141 // Set the detected binding on each alias with this aliasee.
142 for (auto &Alias : Symver.second)
143 Streamer.EmitSymbolAttribute(Alias, Attr);
147 void ModuleSymbolTable::CollectAsmSymbols(
149 function_ref<void(StringRef, BasicSymbolRef::Flags)> AsmSymbol) {
150 StringRef InlineAsm = M.getModuleInlineAsm();
151 if (InlineAsm.empty())
155 const Triple TT(M.getTargetTriple());
156 const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
157 assert(T && T->hasMCAsmParser());
159 std::unique_ptr<MCRegisterInfo> MRI(T->createMCRegInfo(TT.str()));
163 std::unique_ptr<MCAsmInfo> MAI(T->createMCAsmInfo(*MRI, TT.str()));
167 std::unique_ptr<MCSubtargetInfo> STI(
168 T->createMCSubtargetInfo(TT.str(), "", ""));
172 std::unique_ptr<MCInstrInfo> MCII(T->createMCInstrInfo());
176 MCObjectFileInfo MOFI;
177 MCContext MCCtx(MAI.get(), MRI.get(), &MOFI);
178 MOFI.InitMCObjectFileInfo(TT, /*PIC*/ false, MCCtx);
179 RecordStreamer Streamer(MCCtx);
180 T->createNullTargetStreamer(Streamer);
182 std::unique_ptr<MemoryBuffer> Buffer(MemoryBuffer::getMemBuffer(InlineAsm));
184 SrcMgr.AddNewSourceBuffer(std::move(Buffer), SMLoc());
185 std::unique_ptr<MCAsmParser> Parser(
186 createMCAsmParser(SrcMgr, MCCtx, Streamer, *MAI));
188 MCTargetOptions MCOptions;
189 std::unique_ptr<MCTargetAsmParser> TAP(
190 T->createMCAsmParser(*STI, *Parser, *MCII, MCOptions));
194 Parser->setTargetParser(*TAP);
195 if (Parser->Run(false))
198 handleSymverAliases(M, Streamer);
200 for (auto &KV : Streamer) {
201 StringRef Key = KV.first();
202 RecordStreamer::State Value = KV.second;
203 // FIXME: For now we just assume that all asm symbols are executable.
204 uint32_t Res = BasicSymbolRef::SF_Executable;
206 case RecordStreamer::NeverSeen:
207 llvm_unreachable("NeverSeen should have been replaced earlier");
208 case RecordStreamer::DefinedGlobal:
209 Res |= BasicSymbolRef::SF_Global;
211 case RecordStreamer::Defined:
213 case RecordStreamer::Global:
214 case RecordStreamer::Used:
215 Res |= BasicSymbolRef::SF_Undefined;
216 Res |= BasicSymbolRef::SF_Global;
218 case RecordStreamer::DefinedWeak:
219 Res |= BasicSymbolRef::SF_Weak;
220 Res |= BasicSymbolRef::SF_Global;
222 case RecordStreamer::UndefinedWeak:
223 Res |= BasicSymbolRef::SF_Weak;
224 Res |= BasicSymbolRef::SF_Undefined;
226 AsmSymbol(Key, BasicSymbolRef::Flags(Res));
230 void ModuleSymbolTable::printSymbolName(raw_ostream &OS, Symbol S) const {
231 if (S.is<AsmSymbol *>()) {
232 OS << S.get<AsmSymbol *>()->first;
236 auto *GV = S.get<GlobalValue *>();
237 if (GV->hasDLLImportStorageClass())
240 Mang.getNameWithPrefix(OS, GV, false);
243 uint32_t ModuleSymbolTable::getSymbolFlags(Symbol S) const {
244 if (S.is<AsmSymbol *>())
245 return S.get<AsmSymbol *>()->second;
247 auto *GV = S.get<GlobalValue *>();
249 uint32_t Res = BasicSymbolRef::SF_None;
250 if (GV->isDeclarationForLinker())
251 Res |= BasicSymbolRef::SF_Undefined;
252 else if (GV->hasHiddenVisibility() && !GV->hasLocalLinkage())
253 Res |= BasicSymbolRef::SF_Hidden;
254 if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV)) {
255 if (GVar->isConstant())
256 Res |= BasicSymbolRef::SF_Const;
258 if (dyn_cast_or_null<Function>(GV->getBaseObject()))
259 Res |= BasicSymbolRef::SF_Executable;
260 if (isa<GlobalAlias>(GV))
261 Res |= BasicSymbolRef::SF_Indirect;
262 if (GV->hasPrivateLinkage())
263 Res |= BasicSymbolRef::SF_FormatSpecific;
264 if (!GV->hasLocalLinkage())
265 Res |= BasicSymbolRef::SF_Global;
266 if (GV->hasCommonLinkage())
267 Res |= BasicSymbolRef::SF_Common;
268 if (GV->hasLinkOnceLinkage() || GV->hasWeakLinkage() ||
269 GV->hasExternalWeakLinkage())
270 Res |= BasicSymbolRef::SF_Weak;
272 if (GV->getName().startswith("llvm."))
273 Res |= BasicSymbolRef::SF_FormatSpecific;
274 else if (auto *Var = dyn_cast<GlobalVariable>(GV)) {
275 if (Var->getSection() == "llvm.metadata")
276 Res |= BasicSymbolRef::SF_FormatSpecific;