1 //===- ModuleSymbolTable.cpp - symbol table for in-memory IR --------------===// 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 // This class represents a symbol table built from in-memory IR. It provides 10 // access to GlobalValues and should only be used if such access is required 11 // (e.g. in the LTO implementation). 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "llvm/Object/ModuleSymbolTable.h" 16 #include "RecordStreamer.h" 17 #include "llvm/ADT/STLExtras.h" 18 #include "llvm/ADT/SmallString.h" 19 #include "llvm/ADT/StringMap.h" 20 #include "llvm/ADT/StringRef.h" 21 #include "llvm/ADT/Triple.h" 22 #include "llvm/IR/Function.h" 23 #include "llvm/IR/GlobalAlias.h" 24 #include "llvm/IR/GlobalValue.h" 25 #include "llvm/IR/GlobalVariable.h" 26 #include "llvm/IR/Module.h" 27 #include "llvm/MC/MCAsmInfo.h" 28 #include "llvm/MC/MCContext.h" 29 #include "llvm/MC/MCDirectives.h" 30 #include "llvm/MC/MCInstrInfo.h" 31 #include "llvm/MC/MCObjectFileInfo.h" 32 #include "llvm/MC/MCParser/MCAsmParser.h" 33 #include "llvm/MC/MCParser/MCTargetAsmParser.h" 34 #include "llvm/MC/MCRegisterInfo.h" 35 #include "llvm/MC/MCSubtargetInfo.h" 36 #include "llvm/MC/MCSymbol.h" 37 #include "llvm/MC/MCTargetOptions.h" 38 #include "llvm/Object/SymbolicFile.h" 39 #include "llvm/Support/Casting.h" 40 #include "llvm/Support/CodeGen.h" 41 #include "llvm/Support/ErrorHandling.h" 42 #include "llvm/Support/MemoryBuffer.h" 43 #include "llvm/Support/SMLoc.h" 44 #include "llvm/Support/SourceMgr.h" 45 #include "llvm/Support/TargetRegistry.h" 46 #include "llvm/Support/raw_ostream.h" 47 #include <algorithm> 48 #include <cassert> 49 #include <cstdint> 50 #include <memory> 51 #include <string> 52 53 using namespace llvm; 54 using namespace object; 55 56 void ModuleSymbolTable::addModule(Module *M) { 57 if (FirstMod) 58 assert(FirstMod->getTargetTriple() == M->getTargetTriple()); 59 else 60 FirstMod = M; 61 62 for (GlobalValue &GV : M->global_values()) 63 SymTab.push_back(&GV); 64 65 CollectAsmSymbols(*M, [this](StringRef Name, BasicSymbolRef::Flags Flags) { 66 SymTab.push_back(new (AsmSymbols.Allocate()) 67 AsmSymbol(std::string(Name), Flags)); 68 }); 69 } 70 71 static void 72 initializeRecordStreamer(const Module &M, 73 function_ref<void(RecordStreamer &)> Init) { 74 StringRef InlineAsm = M.getModuleInlineAsm(); 75 if (InlineAsm.empty()) 76 return; 77 78 std::string Err; 79 const Triple TT(M.getTargetTriple()); 80 const Target *T = TargetRegistry::lookupTarget(TT.str(), Err); 81 assert(T && T->hasMCAsmParser()); 82 83 std::unique_ptr<MCRegisterInfo> MRI(T->createMCRegInfo(TT.str())); 84 if (!MRI) 85 return; 86 87 MCTargetOptions MCOptions; 88 std::unique_ptr<MCAsmInfo> MAI(T->createMCAsmInfo(*MRI, TT.str(), MCOptions)); 89 if (!MAI) 90 return; 91 92 std::unique_ptr<MCSubtargetInfo> STI( 93 T->createMCSubtargetInfo(TT.str(), "", "")); 94 if (!STI) 95 return; 96 97 std::unique_ptr<MCInstrInfo> MCII(T->createMCInstrInfo()); 98 if (!MCII) 99 return; 100 101 MCObjectFileInfo MOFI; 102 MCContext MCCtx(MAI.get(), MRI.get(), &MOFI); 103 MOFI.InitMCObjectFileInfo(TT, /*PIC*/ false, MCCtx); 104 MOFI.setSDKVersion(M.getSDKVersion()); 105 RecordStreamer Streamer(MCCtx, M); 106 T->createNullTargetStreamer(Streamer); 107 108 std::unique_ptr<MemoryBuffer> Buffer(MemoryBuffer::getMemBuffer(InlineAsm)); 109 SourceMgr SrcMgr; 110 SrcMgr.AddNewSourceBuffer(std::move(Buffer), SMLoc()); 111 std::unique_ptr<MCAsmParser> Parser( 112 createMCAsmParser(SrcMgr, MCCtx, Streamer, *MAI)); 113 114 std::unique_ptr<MCTargetAsmParser> TAP( 115 T->createMCAsmParser(*STI, *Parser, *MCII, MCOptions)); 116 if (!TAP) 117 return; 118 119 Parser->setTargetParser(*TAP); 120 if (Parser->Run(false)) 121 return; 122 123 Init(Streamer); 124 } 125 126 void ModuleSymbolTable::CollectAsmSymbols( 127 const Module &M, 128 function_ref<void(StringRef, BasicSymbolRef::Flags)> AsmSymbol) { 129 initializeRecordStreamer(M, [&](RecordStreamer &Streamer) { 130 Streamer.flushSymverDirectives(); 131 132 for (auto &KV : Streamer) { 133 StringRef Key = KV.first(); 134 RecordStreamer::State Value = KV.second; 135 // FIXME: For now we just assume that all asm symbols are executable. 136 uint32_t Res = BasicSymbolRef::SF_Executable; 137 switch (Value) { 138 case RecordStreamer::NeverSeen: 139 llvm_unreachable("NeverSeen should have been replaced earlier"); 140 case RecordStreamer::DefinedGlobal: 141 Res |= BasicSymbolRef::SF_Global; 142 break; 143 case RecordStreamer::Defined: 144 break; 145 case RecordStreamer::Global: 146 case RecordStreamer::Used: 147 Res |= BasicSymbolRef::SF_Undefined; 148 Res |= BasicSymbolRef::SF_Global; 149 break; 150 case RecordStreamer::DefinedWeak: 151 Res |= BasicSymbolRef::SF_Weak; 152 Res |= BasicSymbolRef::SF_Global; 153 break; 154 case RecordStreamer::UndefinedWeak: 155 Res |= BasicSymbolRef::SF_Weak; 156 Res |= BasicSymbolRef::SF_Undefined; 157 } 158 AsmSymbol(Key, BasicSymbolRef::Flags(Res)); 159 } 160 }); 161 } 162 163 void ModuleSymbolTable::CollectAsmSymvers( 164 const Module &M, function_ref<void(StringRef, StringRef)> AsmSymver) { 165 initializeRecordStreamer(M, [&](RecordStreamer &Streamer) { 166 for (auto &KV : Streamer.symverAliases()) 167 for (auto &Alias : KV.second) 168 AsmSymver(KV.first->getName(), Alias); 169 }); 170 } 171 172 void ModuleSymbolTable::printSymbolName(raw_ostream &OS, Symbol S) const { 173 if (S.is<AsmSymbol *>()) { 174 OS << S.get<AsmSymbol *>()->first; 175 return; 176 } 177 178 auto *GV = S.get<GlobalValue *>(); 179 if (GV->hasDLLImportStorageClass()) 180 OS << "__imp_"; 181 182 Mang.getNameWithPrefix(OS, GV, false); 183 } 184 185 uint32_t ModuleSymbolTable::getSymbolFlags(Symbol S) const { 186 if (S.is<AsmSymbol *>()) 187 return S.get<AsmSymbol *>()->second; 188 189 auto *GV = S.get<GlobalValue *>(); 190 191 uint32_t Res = BasicSymbolRef::SF_None; 192 if (GV->isDeclarationForLinker()) 193 Res |= BasicSymbolRef::SF_Undefined; 194 else if (GV->hasHiddenVisibility() && !GV->hasLocalLinkage()) 195 Res |= BasicSymbolRef::SF_Hidden; 196 if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV)) { 197 if (GVar->isConstant()) 198 Res |= BasicSymbolRef::SF_Const; 199 } 200 if (dyn_cast_or_null<Function>(GV->getBaseObject())) 201 Res |= BasicSymbolRef::SF_Executable; 202 if (isa<GlobalAlias>(GV)) 203 Res |= BasicSymbolRef::SF_Indirect; 204 if (GV->hasPrivateLinkage()) 205 Res |= BasicSymbolRef::SF_FormatSpecific; 206 if (!GV->hasLocalLinkage()) 207 Res |= BasicSymbolRef::SF_Global; 208 if (GV->hasCommonLinkage()) 209 Res |= BasicSymbolRef::SF_Common; 210 if (GV->hasLinkOnceLinkage() || GV->hasWeakLinkage() || 211 GV->hasExternalWeakLinkage()) 212 Res |= BasicSymbolRef::SF_Weak; 213 214 if (GV->getName().startswith("llvm.")) 215 Res |= BasicSymbolRef::SF_FormatSpecific; 216 else if (auto *Var = dyn_cast<GlobalVariable>(GV)) { 217 if (Var->getSection() == "llvm.metadata") 218 Res |= BasicSymbolRef::SF_FormatSpecific; 219 } 220 221 return Res; 222 } 223