267 lines
8.2 KiB
C++
267 lines
8.2 KiB
C++
//===- ModuleSymbolTable.cpp - symbol table for in-memory IR ----*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This class represents a symbol table built from in-memory IR. It provides
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// access to GlobalValues and should only be used if such access is required
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// (e.g. in the LTO implementation).
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Object/IRObjectFile.h"
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#include "RecordStreamer.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/Bitcode/BitcodeReader.h"
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#include "llvm/IR/GVMaterializer.h"
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#include "llvm/IR/LLVMContext.h"
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#include "llvm/IR/Mangler.h"
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#include "llvm/IR/Module.h"
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#include "llvm/MC/MCAsmInfo.h"
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#include "llvm/MC/MCContext.h"
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#include "llvm/MC/MCInstrInfo.h"
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#include "llvm/MC/MCObjectFileInfo.h"
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#include "llvm/MC/MCParser/MCAsmParser.h"
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#include "llvm/MC/MCParser/MCTargetAsmParser.h"
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#include "llvm/MC/MCRegisterInfo.h"
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#include "llvm/MC/MCSubtargetInfo.h"
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#include "llvm/Object/ObjectFile.h"
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#include "llvm/Support/MemoryBuffer.h"
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#include "llvm/Support/SourceMgr.h"
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#include "llvm/Support/TargetRegistry.h"
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#include "llvm/Support/raw_ostream.h"
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using namespace llvm;
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using namespace object;
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void ModuleSymbolTable::addModule(Module *M) {
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if (FirstMod)
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assert(FirstMod->getTargetTriple() == M->getTargetTriple());
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else
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FirstMod = M;
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for (Function &F : *M)
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SymTab.push_back(&F);
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for (GlobalVariable &GV : M->globals())
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SymTab.push_back(&GV);
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for (GlobalAlias &GA : M->aliases())
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SymTab.push_back(&GA);
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CollectAsmSymbols(*M, [this](StringRef Name, BasicSymbolRef::Flags Flags) {
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SymTab.push_back(new (AsmSymbols.Allocate()) AsmSymbol(Name, Flags));
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});
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}
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// Ensure ELF .symver aliases get the same binding as the defined symbol
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// they alias with.
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static void handleSymverAliases(const Module &M, RecordStreamer &Streamer) {
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if (Streamer.symverAliases().empty())
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return;
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// The name in the assembler will be mangled, but the name in the IR
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// might not, so we first compute a mapping from mangled name to GV.
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Mangler Mang;
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SmallString<64> MangledName;
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StringMap<const GlobalValue *> MangledNameMap;
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auto GetMangledName = [&](const GlobalValue &GV) {
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if (!GV.hasName())
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return;
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MangledName.clear();
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MangledName.reserve(GV.getName().size() + 1);
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Mang.getNameWithPrefix(MangledName, &GV, /*CannotUsePrivateLabel=*/false);
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MangledNameMap[MangledName] = &GV;
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};
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for (const Function &F : M)
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GetMangledName(F);
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for (const GlobalVariable &GV : M.globals())
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GetMangledName(GV);
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for (const GlobalAlias &GA : M.aliases())
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GetMangledName(GA);
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// Walk all the recorded .symver aliases, and set up the binding
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// for each alias.
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for (auto &Symver : Streamer.symverAliases()) {
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const MCSymbol *Aliasee = Symver.first;
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MCSymbolAttr Attr = MCSA_Invalid;
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// First check if the aliasee binding was recorded in the asm.
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RecordStreamer::State state = Streamer.getSymbolState(Aliasee);
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switch (state) {
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case RecordStreamer::Global:
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case RecordStreamer::DefinedGlobal:
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Attr = MCSA_Global;
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break;
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case RecordStreamer::UndefinedWeak:
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case RecordStreamer::DefinedWeak:
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Attr = MCSA_Weak;
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break;
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default:
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break;
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}
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// If we don't have a symbol attribute from assembly, then check if
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// the aliasee was defined in the IR.
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if (Attr == MCSA_Invalid) {
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const auto *GV = M.getNamedValue(Aliasee->getName());
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if (!GV) {
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auto MI = MangledNameMap.find(Aliasee->getName());
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if (MI != MangledNameMap.end())
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GV = MI->second;
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else
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continue;
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}
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if (GV->hasExternalLinkage())
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Attr = MCSA_Global;
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else if (GV->hasLocalLinkage())
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Attr = MCSA_Local;
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else if (GV->isWeakForLinker())
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Attr = MCSA_Weak;
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}
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if (Attr == MCSA_Invalid)
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continue;
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// Set the detected binding on each alias with this aliasee.
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for (auto &Alias : Symver.second)
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Streamer.EmitSymbolAttribute(Alias, Attr);
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}
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}
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void ModuleSymbolTable::CollectAsmSymbols(
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const Module &M,
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function_ref<void(StringRef, BasicSymbolRef::Flags)> AsmSymbol) {
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StringRef InlineAsm = M.getModuleInlineAsm();
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if (InlineAsm.empty())
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return;
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std::string Err;
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const Triple TT(M.getTargetTriple());
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const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
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assert(T && T->hasMCAsmParser());
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std::unique_ptr<MCRegisterInfo> MRI(T->createMCRegInfo(TT.str()));
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if (!MRI)
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return;
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std::unique_ptr<MCAsmInfo> MAI(T->createMCAsmInfo(*MRI, TT.str()));
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if (!MAI)
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return;
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std::unique_ptr<MCSubtargetInfo> STI(
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T->createMCSubtargetInfo(TT.str(), "", ""));
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if (!STI)
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return;
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std::unique_ptr<MCInstrInfo> MCII(T->createMCInstrInfo());
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if (!MCII)
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return;
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MCObjectFileInfo MOFI;
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MCContext MCCtx(MAI.get(), MRI.get(), &MOFI);
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MOFI.InitMCObjectFileInfo(TT, /*PIC*/ false, CodeModel::Default, MCCtx);
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RecordStreamer Streamer(MCCtx);
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T->createNullTargetStreamer(Streamer);
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std::unique_ptr<MemoryBuffer> Buffer(MemoryBuffer::getMemBuffer(InlineAsm));
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SourceMgr SrcMgr;
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SrcMgr.AddNewSourceBuffer(std::move(Buffer), SMLoc());
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std::unique_ptr<MCAsmParser> Parser(
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createMCAsmParser(SrcMgr, MCCtx, Streamer, *MAI));
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MCTargetOptions MCOptions;
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std::unique_ptr<MCTargetAsmParser> TAP(
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T->createMCAsmParser(*STI, *Parser, *MCII, MCOptions));
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if (!TAP)
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return;
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Parser->setTargetParser(*TAP);
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if (Parser->Run(false))
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return;
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handleSymverAliases(M, Streamer);
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for (auto &KV : Streamer) {
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StringRef Key = KV.first();
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RecordStreamer::State Value = KV.second;
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// FIXME: For now we just assume that all asm symbols are executable.
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uint32_t Res = BasicSymbolRef::SF_Executable;
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switch (Value) {
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case RecordStreamer::NeverSeen:
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llvm_unreachable("NeverSeen should have been replaced earlier");
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case RecordStreamer::DefinedGlobal:
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Res |= BasicSymbolRef::SF_Global;
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break;
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case RecordStreamer::Defined:
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break;
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case RecordStreamer::Global:
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case RecordStreamer::Used:
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Res |= BasicSymbolRef::SF_Undefined;
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Res |= BasicSymbolRef::SF_Global;
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break;
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case RecordStreamer::DefinedWeak:
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Res |= BasicSymbolRef::SF_Weak;
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Res |= BasicSymbolRef::SF_Global;
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break;
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case RecordStreamer::UndefinedWeak:
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Res |= BasicSymbolRef::SF_Weak;
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Res |= BasicSymbolRef::SF_Undefined;
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}
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AsmSymbol(Key, BasicSymbolRef::Flags(Res));
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}
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}
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void ModuleSymbolTable::printSymbolName(raw_ostream &OS, Symbol S) const {
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if (S.is<AsmSymbol *>()) {
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OS << S.get<AsmSymbol *>()->first;
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return;
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}
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auto *GV = S.get<GlobalValue *>();
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if (GV->hasDLLImportStorageClass())
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OS << "__imp_";
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Mang.getNameWithPrefix(OS, GV, false);
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}
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uint32_t ModuleSymbolTable::getSymbolFlags(Symbol S) const {
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if (S.is<AsmSymbol *>())
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return S.get<AsmSymbol *>()->second;
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auto *GV = S.get<GlobalValue *>();
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uint32_t Res = BasicSymbolRef::SF_None;
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if (GV->isDeclarationForLinker())
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Res |= BasicSymbolRef::SF_Undefined;
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else if (GV->hasHiddenVisibility() && !GV->hasLocalLinkage())
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Res |= BasicSymbolRef::SF_Hidden;
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if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV)) {
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if (GVar->isConstant())
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Res |= BasicSymbolRef::SF_Const;
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}
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if (dyn_cast_or_null<Function>(GV->getBaseObject()))
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Res |= BasicSymbolRef::SF_Executable;
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if (isa<GlobalAlias>(GV))
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Res |= BasicSymbolRef::SF_Indirect;
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if (GV->hasPrivateLinkage())
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Res |= BasicSymbolRef::SF_FormatSpecific;
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if (!GV->hasLocalLinkage())
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Res |= BasicSymbolRef::SF_Global;
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if (GV->hasCommonLinkage())
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Res |= BasicSymbolRef::SF_Common;
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if (GV->hasLinkOnceLinkage() || GV->hasWeakLinkage() ||
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GV->hasExternalWeakLinkage())
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Res |= BasicSymbolRef::SF_Weak;
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if (GV->getName().startswith("llvm."))
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Res |= BasicSymbolRef::SF_FormatSpecific;
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else if (auto *Var = dyn_cast<GlobalVariable>(GV)) {
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if (Var->getSection() == "llvm.metadata")
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Res |= BasicSymbolRef::SF_FormatSpecific;
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}
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return Res;
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}
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