1 //===- IRSymtab.cpp - implementation of IR symbol tables --------*- C++ -*-===//
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 #include "llvm/Object/IRSymtab.h"
11 #include "llvm/Analysis/ObjectUtils.h"
12 #include "llvm/IR/Mangler.h"
13 #include "llvm/IR/Module.h"
14 #include "llvm/MC/StringTableBuilder.h"
15 #include "llvm/Object/ModuleSymbolTable.h"
16 #include "llvm/Support/Allocator.h"
17 #include "llvm/Support/StringSaver.h"
20 using namespace irsymtab;
24 /// Stores the temporary state that is required to build an IR symbol table.
26 SmallVector<char, 0> &Symtab;
27 SmallVector<char, 0> &Strtab;
28 Builder(SmallVector<char, 0> &Symtab, SmallVector<char, 0> &Strtab)
29 : Symtab(Symtab), Strtab(Strtab) {}
31 StringTableBuilder StrtabBuilder{StringTableBuilder::RAW};
33 BumpPtrAllocator Alloc;
34 StringSaver Saver{Alloc};
36 DenseMap<const Comdat *, unsigned> ComdatMap;
40 std::vector<storage::Comdat> Comdats;
41 std::vector<storage::Module> Mods;
42 std::vector<storage::Symbol> Syms;
43 std::vector<storage::Uncommon> Uncommons;
45 std::string COFFLinkerOpts;
46 raw_string_ostream COFFLinkerOptsOS{COFFLinkerOpts};
48 void setStr(storage::Str &S, StringRef Value) {
49 S.Offset = StrtabBuilder.add(Value);
50 S.Size = Value.size();
53 void writeRange(storage::Range<T> &R, const std::vector<T> &Objs) {
54 R.Offset = Symtab.size();
56 Symtab.insert(Symtab.end(), reinterpret_cast<const char *>(Objs.data()),
57 reinterpret_cast<const char *>(Objs.data() + Objs.size()));
60 Error addModule(Module *M);
61 Error addSymbol(const ModuleSymbolTable &Msymtab,
62 const SmallPtrSet<GlobalValue *, 8> &Used,
63 ModuleSymbolTable::Symbol Sym);
65 Error build(ArrayRef<Module *> Mods);
68 Error Builder::addModule(Module *M) {
69 SmallPtrSet<GlobalValue *, 8> Used;
70 collectUsedGlobalVariables(*M, Used, /*CompilerUsed*/ false);
72 ModuleSymbolTable Msymtab;
76 Mod.Begin = Syms.size();
77 Mod.End = Syms.size() + Msymtab.symbols().size();
78 Mod.UncBegin = Uncommons.size();
81 if (TT.isOSBinFormatCOFF()) {
82 if (auto E = M->materializeMetadata())
84 if (Metadata *Val = M->getModuleFlag("Linker Options")) {
85 MDNode *LinkerOptions = cast<MDNode>(Val);
86 for (const MDOperand &MDOptions : LinkerOptions->operands())
87 for (const MDOperand &MDOption : cast<MDNode>(MDOptions)->operands())
88 COFFLinkerOptsOS << " " << cast<MDString>(MDOption)->getString();
92 for (ModuleSymbolTable::Symbol Msym : Msymtab.symbols())
93 if (Error Err = addSymbol(Msymtab, Used, Msym))
96 return Error::success();
99 Error Builder::addSymbol(const ModuleSymbolTable &Msymtab,
100 const SmallPtrSet<GlobalValue *, 8> &Used,
101 ModuleSymbolTable::Symbol Msym) {
103 storage::Symbol &Sym = Syms.back();
106 storage::Uncommon *Unc = nullptr;
107 auto Uncommon = [&]() -> storage::Uncommon & {
110 Sym.Flags |= 1 << storage::Symbol::FB_has_uncommon;
111 Uncommons.emplace_back();
112 Unc = &Uncommons.back();
114 setStr(Unc->COFFWeakExternFallbackName, "");
118 SmallString<64> Name;
120 raw_svector_ostream OS(Name);
121 Msymtab.printSymbolName(OS, Msym);
123 setStr(Sym.Name, Saver.save(StringRef(Name)));
125 auto Flags = Msymtab.getSymbolFlags(Msym);
126 if (Flags & object::BasicSymbolRef::SF_Undefined)
127 Sym.Flags |= 1 << storage::Symbol::FB_undefined;
128 if (Flags & object::BasicSymbolRef::SF_Weak)
129 Sym.Flags |= 1 << storage::Symbol::FB_weak;
130 if (Flags & object::BasicSymbolRef::SF_Common)
131 Sym.Flags |= 1 << storage::Symbol::FB_common;
132 if (Flags & object::BasicSymbolRef::SF_Indirect)
133 Sym.Flags |= 1 << storage::Symbol::FB_indirect;
134 if (Flags & object::BasicSymbolRef::SF_Global)
135 Sym.Flags |= 1 << storage::Symbol::FB_global;
136 if (Flags & object::BasicSymbolRef::SF_FormatSpecific)
137 Sym.Flags |= 1 << storage::Symbol::FB_format_specific;
138 if (Flags & object::BasicSymbolRef::SF_Executable)
139 Sym.Flags |= 1 << storage::Symbol::FB_executable;
141 Sym.ComdatIndex = -1;
142 auto *GV = Msym.dyn_cast<GlobalValue *>();
144 setStr(Sym.IRName, "");
145 return Error::success();
148 setStr(Sym.IRName, GV->getName());
151 Sym.Flags |= 1 << storage::Symbol::FB_used;
152 if (GV->isThreadLocal())
153 Sym.Flags |= 1 << storage::Symbol::FB_tls;
154 if (GV->hasGlobalUnnamedAddr())
155 Sym.Flags |= 1 << storage::Symbol::FB_unnamed_addr;
156 if (canBeOmittedFromSymbolTable(GV))
157 Sym.Flags |= 1 << storage::Symbol::FB_may_omit;
158 Sym.Flags |= unsigned(GV->getVisibility()) << storage::Symbol::FB_visibility;
160 if (Flags & object::BasicSymbolRef::SF_Common) {
161 Uncommon().CommonSize = GV->getParent()->getDataLayout().getTypeAllocSize(
162 GV->getType()->getElementType());
163 Uncommon().CommonAlign = GV->getAlignment();
166 const GlobalObject *Base = GV->getBaseObject();
168 return make_error<StringError>("Unable to determine comdat of alias!",
169 inconvertibleErrorCode());
170 if (const Comdat *C = Base->getComdat()) {
171 auto P = ComdatMap.insert(std::make_pair(C, Comdats.size()));
172 Sym.ComdatIndex = P.first->second;
175 storage::Comdat Comdat;
176 setStr(Comdat.Name, C->getName());
177 Comdats.push_back(Comdat);
181 if (TT.isOSBinFormatCOFF()) {
182 emitLinkerFlagsForGlobalCOFF(COFFLinkerOptsOS, GV, TT, Mang);
184 if ((Flags & object::BasicSymbolRef::SF_Weak) &&
185 (Flags & object::BasicSymbolRef::SF_Indirect)) {
186 std::string FallbackName;
187 raw_string_ostream OS(FallbackName);
188 Msymtab.printSymbolName(
189 OS, cast<GlobalValue>(
190 cast<GlobalAlias>(GV)->getAliasee()->stripPointerCasts()));
192 setStr(Uncommon().COFFWeakExternFallbackName, Saver.save(FallbackName));
196 return Error::success();
199 Error Builder::build(ArrayRef<Module *> IRMods) {
202 assert(!IRMods.empty());
203 setStr(Hdr.TargetTriple, IRMods[0]->getTargetTriple());
204 setStr(Hdr.SourceFileName, IRMods[0]->getSourceFileName());
205 TT = Triple(IRMods[0]->getTargetTriple());
207 for (auto *M : IRMods)
208 if (Error Err = addModule(M))
211 COFFLinkerOptsOS.flush();
212 setStr(Hdr.COFFLinkerOpts, COFFLinkerOpts);
214 // We are about to fill in the header's range fields, so reserve space for it
215 // and copy it in afterwards.
216 Symtab.resize(sizeof(storage::Header));
217 writeRange(Hdr.Modules, Mods);
218 writeRange(Hdr.Comdats, Comdats);
219 writeRange(Hdr.Symbols, Syms);
220 writeRange(Hdr.Uncommons, Uncommons);
222 *reinterpret_cast<storage::Header *>(Symtab.data()) = Hdr;
224 raw_svector_ostream OS(Strtab);
225 StrtabBuilder.finalizeInOrder();
226 StrtabBuilder.write(OS);
228 return Error::success();
231 } // anonymous namespace
233 Error irsymtab::build(ArrayRef<Module *> Mods, SmallVector<char, 0> &Symtab,
234 SmallVector<char, 0> &Strtab) {
235 return Builder(Symtab, Strtab).build(Mods);