xref: /freebsd/contrib/llvm-project/llvm/lib/Object/ModuleSymbolTable.cpp (revision 77a1348b3c1cfe8547be49a121b56299a1e18b69)
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()) AsmSymbol(Name, Flags));
67   });
68 }
69 
70 static void
71 initializeRecordStreamer(const Module &M,
72                          function_ref<void(RecordStreamer &)> Init) {
73   StringRef InlineAsm = M.getModuleInlineAsm();
74   if (InlineAsm.empty())
75     return;
76 
77   std::string Err;
78   const Triple TT(M.getTargetTriple());
79   const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
80   assert(T && T->hasMCAsmParser());
81 
82   std::unique_ptr<MCRegisterInfo> MRI(T->createMCRegInfo(TT.str()));
83   if (!MRI)
84     return;
85 
86   MCTargetOptions MCOptions;
87   std::unique_ptr<MCAsmInfo> MAI(T->createMCAsmInfo(*MRI, TT.str(), MCOptions));
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   MOFI.setSDKVersion(M.getSDKVersion());
104   RecordStreamer Streamer(MCCtx, M);
105   T->createNullTargetStreamer(Streamer);
106 
107   std::unique_ptr<MemoryBuffer> Buffer(MemoryBuffer::getMemBuffer(InlineAsm));
108   SourceMgr SrcMgr;
109   SrcMgr.AddNewSourceBuffer(std::move(Buffer), SMLoc());
110   std::unique_ptr<MCAsmParser> Parser(
111       createMCAsmParser(SrcMgr, MCCtx, Streamer, *MAI));
112 
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 
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 
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 
171 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 
184 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