1 //===- ModuleSymbolTable.cpp - symbol table for in-memory IR --------------===//
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 // 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).
13 //
14 //===----------------------------------------------------------------------===//
15
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/Module.h"
28 #include "llvm/MC/MCAsmInfo.h"
29 #include "llvm/MC/MCContext.h"
30 #include "llvm/MC/MCDirectives.h"
31 #include "llvm/MC/MCInstrInfo.h"
32 #include "llvm/MC/MCObjectFileInfo.h"
33 #include "llvm/MC/MCParser/MCAsmParser.h"
34 #include "llvm/MC/MCParser/MCTargetAsmParser.h"
35 #include "llvm/MC/MCRegisterInfo.h"
36 #include "llvm/MC/MCSubtargetInfo.h"
37 #include "llvm/MC/MCSymbol.h"
38 #include "llvm/MC/MCTargetOptions.h"
39 #include "llvm/Object/SymbolicFile.h"
40 #include "llvm/Support/Casting.h"
41 #include "llvm/Support/CodeGen.h"
42 #include "llvm/Support/ErrorHandling.h"
43 #include "llvm/Support/MemoryBuffer.h"
44 #include "llvm/Support/SMLoc.h"
45 #include "llvm/Support/SourceMgr.h"
46 #include "llvm/Support/TargetRegistry.h"
47 #include "llvm/Support/raw_ostream.h"
48 #include <algorithm>
49 #include <cassert>
50 #include <cstdint>
51 #include <memory>
52 #include <string>
53
54 using namespace llvm;
55 using namespace object;
56
addModule(Module * M)57 void ModuleSymbolTable::addModule(Module *M) {
58 if (FirstMod)
59 assert(FirstMod->getTargetTriple() == M->getTargetTriple());
60 else
61 FirstMod = M;
62
63 for (GlobalValue &GV : M->global_values())
64 SymTab.push_back(&GV);
65
66 CollectAsmSymbols(*M, [this](StringRef Name, BasicSymbolRef::Flags Flags) {
67 SymTab.push_back(new (AsmSymbols.Allocate()) AsmSymbol(Name, Flags));
68 });
69 }
70
71 static void
initializeRecordStreamer(const Module & M,function_ref<void (RecordStreamer &)> Init)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 std::unique_ptr<MCAsmInfo> MAI(T->createMCAsmInfo(*MRI, TT.str()));
88 if (!MAI)
89 return;
90
91 std::unique_ptr<MCSubtargetInfo> STI(
92 T->createMCSubtargetInfo(TT.str(), "", ""));
93 if (!STI)
94 return;
95
96 std::unique_ptr<MCInstrInfo> MCII(T->createMCInstrInfo());
97 if (!MCII)
98 return;
99
100 MCObjectFileInfo MOFI;
101 MCContext MCCtx(MAI.get(), MRI.get(), &MOFI);
102 MOFI.InitMCObjectFileInfo(TT, /*PIC*/ false, MCCtx);
103 RecordStreamer Streamer(MCCtx, M);
104 T->createNullTargetStreamer(Streamer);
105
106 std::unique_ptr<MemoryBuffer> Buffer(MemoryBuffer::getMemBuffer(InlineAsm));
107 SourceMgr SrcMgr;
108 SrcMgr.AddNewSourceBuffer(std::move(Buffer), SMLoc());
109 std::unique_ptr<MCAsmParser> Parser(
110 createMCAsmParser(SrcMgr, MCCtx, Streamer, *MAI));
111
112 MCTargetOptions MCOptions;
113 std::unique_ptr<MCTargetAsmParser> TAP(
114 T->createMCAsmParser(*STI, *Parser, *MCII, MCOptions));
115 if (!TAP)
116 return;
117
118 Parser->setTargetParser(*TAP);
119 if (Parser->Run(false))
120 return;
121
122 Init(Streamer);
123 }
124
CollectAsmSymbols(const Module & M,function_ref<void (StringRef,BasicSymbolRef::Flags)> AsmSymbol)125 void ModuleSymbolTable::CollectAsmSymbols(
126 const Module &M,
127 function_ref<void(StringRef, BasicSymbolRef::Flags)> AsmSymbol) {
128 initializeRecordStreamer(M, [&](RecordStreamer &Streamer) {
129 Streamer.flushSymverDirectives();
130
131 for (auto &KV : Streamer) {
132 StringRef Key = KV.first();
133 RecordStreamer::State Value = KV.second;
134 // FIXME: For now we just assume that all asm symbols are executable.
135 uint32_t Res = BasicSymbolRef::SF_Executable;
136 switch (Value) {
137 case RecordStreamer::NeverSeen:
138 llvm_unreachable("NeverSeen should have been replaced earlier");
139 case RecordStreamer::DefinedGlobal:
140 Res |= BasicSymbolRef::SF_Global;
141 break;
142 case RecordStreamer::Defined:
143 break;
144 case RecordStreamer::Global:
145 case RecordStreamer::Used:
146 Res |= BasicSymbolRef::SF_Undefined;
147 Res |= BasicSymbolRef::SF_Global;
148 break;
149 case RecordStreamer::DefinedWeak:
150 Res |= BasicSymbolRef::SF_Weak;
151 Res |= BasicSymbolRef::SF_Global;
152 break;
153 case RecordStreamer::UndefinedWeak:
154 Res |= BasicSymbolRef::SF_Weak;
155 Res |= BasicSymbolRef::SF_Undefined;
156 }
157 AsmSymbol(Key, BasicSymbolRef::Flags(Res));
158 }
159 });
160 }
161
CollectAsmSymvers(const Module & M,function_ref<void (StringRef,StringRef)> AsmSymver)162 void ModuleSymbolTable::CollectAsmSymvers(
163 const Module &M, function_ref<void(StringRef, StringRef)> AsmSymver) {
164 initializeRecordStreamer(M, [&](RecordStreamer &Streamer) {
165 for (auto &KV : Streamer.symverAliases())
166 for (auto &Alias : KV.second)
167 AsmSymver(KV.first->getName(), Alias);
168 });
169 }
170
printSymbolName(raw_ostream & OS,Symbol S) const171 void ModuleSymbolTable::printSymbolName(raw_ostream &OS, Symbol S) const {
172 if (S.is<AsmSymbol *>()) {
173 OS << S.get<AsmSymbol *>()->first;
174 return;
175 }
176
177 auto *GV = S.get<GlobalValue *>();
178 if (GV->hasDLLImportStorageClass())
179 OS << "__imp_";
180
181 Mang.getNameWithPrefix(OS, GV, false);
182 }
183
getSymbolFlags(Symbol S) const184 uint32_t ModuleSymbolTable::getSymbolFlags(Symbol S) const {
185 if (S.is<AsmSymbol *>())
186 return S.get<AsmSymbol *>()->second;
187
188 auto *GV = S.get<GlobalValue *>();
189
190 uint32_t Res = BasicSymbolRef::SF_None;
191 if (GV->isDeclarationForLinker())
192 Res |= BasicSymbolRef::SF_Undefined;
193 else if (GV->hasHiddenVisibility() && !GV->hasLocalLinkage())
194 Res |= BasicSymbolRef::SF_Hidden;
195 if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV)) {
196 if (GVar->isConstant())
197 Res |= BasicSymbolRef::SF_Const;
198 }
199 if (dyn_cast_or_null<Function>(GV->getBaseObject()))
200 Res |= BasicSymbolRef::SF_Executable;
201 if (isa<GlobalAlias>(GV))
202 Res |= BasicSymbolRef::SF_Indirect;
203 if (GV->hasPrivateLinkage())
204 Res |= BasicSymbolRef::SF_FormatSpecific;
205 if (!GV->hasLocalLinkage())
206 Res |= BasicSymbolRef::SF_Global;
207 if (GV->hasCommonLinkage())
208 Res |= BasicSymbolRef::SF_Common;
209 if (GV->hasLinkOnceLinkage() || GV->hasWeakLinkage() ||
210 GV->hasExternalWeakLinkage())
211 Res |= BasicSymbolRef::SF_Weak;
212
213 if (GV->getName().startswith("llvm."))
214 Res |= BasicSymbolRef::SF_FormatSpecific;
215 else if (auto *Var = dyn_cast<GlobalVariable>(GV)) {
216 if (Var->getSection() == "llvm.metadata")
217 Res |= BasicSymbolRef::SF_FormatSpecific;
218 }
219
220 return Res;
221 }
222