Imported Upstream version 5.18.0.161

Former-commit-id: 4db48158d3a35497b8f118ab21b5f08ac3d86d98

external/llvm/lib/Object/ModuleSymbolTable.cpp

@@ -0,0 +1,280 @@
+//===- ModuleSymbolTable.cpp - symbol table for in-memory IR --------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This class represents a symbol table built from in-memory IR. It provides
+// access to GlobalValues and should only be used if such access is required
+// (e.g. in the LTO implementation).
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Object/ModuleSymbolTable.h"
+#include "RecordStreamer.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/Triple.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/GlobalAlias.h"
+#include "llvm/IR/GlobalValue.h"
+#include "llvm/IR/GlobalVariable.h"
+#include "llvm/IR/Mangler.h"
+#include "llvm/IR/Module.h"
+#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCDirectives.h"
+#include "llvm/MC/MCInstrInfo.h"
+#include "llvm/MC/MCObjectFileInfo.h"
+#include "llvm/MC/MCParser/MCAsmParser.h"
+#include "llvm/MC/MCParser/MCTargetAsmParser.h"
+#include "llvm/MC/MCRegisterInfo.h"
+#include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/MC/MCSymbol.h"
+#include "llvm/MC/MCTargetOptions.h"
+#include "llvm/Object/SymbolicFile.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/CodeGen.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/SMLoc.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/raw_ostream.h"
+#include <algorithm>
+#include <cassert>
+#include <cstdint>
+#include <memory>
+#include <string>
+
+using namespace llvm;
+using namespace object;
+
+void ModuleSymbolTable::addModule(Module *M) {
+  if (FirstMod)
+    assert(FirstMod->getTargetTriple() == M->getTargetTriple());
+  else
+    FirstMod = M;
+
+  for (GlobalValue &GV : M->global_values())
+    SymTab.push_back(&GV);
+
+  CollectAsmSymbols(*M, [this](StringRef Name, BasicSymbolRef::Flags Flags) {
+    SymTab.push_back(new (AsmSymbols.Allocate()) AsmSymbol(Name, Flags));
+  });
+}
+
+// Ensure ELF .symver aliases get the same binding as the defined symbol
+// they alias with.
+static void handleSymverAliases(const Module &M, RecordStreamer &Streamer) {
+  if (Streamer.symverAliases().empty())
+    return;
+
+  // The name in the assembler will be mangled, but the name in the IR
+  // might not, so we first compute a mapping from mangled name to GV.
+  Mangler Mang;
+  SmallString<64> MangledName;
+  StringMap<const GlobalValue *> MangledNameMap;
+  auto GetMangledName = [&](const GlobalValue &GV) {
+    if (!GV.hasName())
+      return;
+
+    MangledName.clear();
+    MangledName.reserve(GV.getName().size() + 1);
+    Mang.getNameWithPrefix(MangledName, &GV, /*CannotUsePrivateLabel=*/false);
+    MangledNameMap[MangledName] = &GV;
+  };
+  for (const Function &F : M)
+    GetMangledName(F);
+  for (const GlobalVariable &GV : M.globals())
+    GetMangledName(GV);
+  for (const GlobalAlias &GA : M.aliases())
+    GetMangledName(GA);
+
+  // Walk all the recorded .symver aliases, and set up the binding
+  // for each alias.
+  for (auto &Symver : Streamer.symverAliases()) {
+    const MCSymbol *Aliasee = Symver.first;
+    MCSymbolAttr Attr = MCSA_Invalid;
+
+    // First check if the aliasee binding was recorded in the asm.
+    RecordStreamer::State state = Streamer.getSymbolState(Aliasee);
+    switch (state) {
+    case RecordStreamer::Global:
+    case RecordStreamer::DefinedGlobal:
+      Attr = MCSA_Global;
+      break;
+    case RecordStreamer::UndefinedWeak:
+    case RecordStreamer::DefinedWeak:
+      Attr = MCSA_Weak;
+      break;
+    default:
+      break;
+    }
+
+    // If we don't have a symbol attribute from assembly, then check if
+    // the aliasee was defined in the IR.
+    if (Attr == MCSA_Invalid) {
+      const auto *GV = M.getNamedValue(Aliasee->getName());
+      if (!GV) {
+        auto MI = MangledNameMap.find(Aliasee->getName());
+        if (MI != MangledNameMap.end())
+          GV = MI->second;
+        else
+          continue;
+      }
+      if (GV->hasExternalLinkage())
+        Attr = MCSA_Global;
+      else if (GV->hasLocalLinkage())
+        Attr = MCSA_Local;
+      else if (GV->isWeakForLinker())
+        Attr = MCSA_Weak;
+    }
+    if (Attr == MCSA_Invalid)
+      continue;
+
+    // Set the detected binding on each alias with this aliasee.
+    for (auto &Alias : Symver.second)
+      Streamer.EmitSymbolAttribute(Alias, Attr);
+  }
+}
+
+void ModuleSymbolTable::CollectAsmSymbols(
+    const Module &M,
+    function_ref<void(StringRef, BasicSymbolRef::Flags)> AsmSymbol) {
+  StringRef InlineAsm = M.getModuleInlineAsm();
+  if (InlineAsm.empty())
+    return;
+
+  std::string Err;
+  const Triple TT(M.getTargetTriple());
+  const Target *T = TargetRegistry::lookupTarget(TT.str(), Err);
+  assert(T && T->hasMCAsmParser());
+
+  std::unique_ptr<MCRegisterInfo> MRI(T->createMCRegInfo(TT.str()));
+  if (!MRI)
+    return;
+
+  std::unique_ptr<MCAsmInfo> MAI(T->createMCAsmInfo(*MRI, TT.str()));
+  if (!MAI)
+    return;
+
+  std::unique_ptr<MCSubtargetInfo> STI(
+      T->createMCSubtargetInfo(TT.str(), "", ""));
+  if (!STI)
+    return;
+
+  std::unique_ptr<MCInstrInfo> MCII(T->createMCInstrInfo());
+  if (!MCII)
+    return;
+
+  MCObjectFileInfo MOFI;
+  MCContext MCCtx(MAI.get(), MRI.get(), &MOFI);
+  MOFI.InitMCObjectFileInfo(TT, /*PIC*/ false, MCCtx);
+  RecordStreamer Streamer(MCCtx);
+  T->createNullTargetStreamer(Streamer);
+
+  std::unique_ptr<MemoryBuffer> Buffer(MemoryBuffer::getMemBuffer(InlineAsm));
+  SourceMgr SrcMgr;
+  SrcMgr.AddNewSourceBuffer(std::move(Buffer), SMLoc());
+  std::unique_ptr<MCAsmParser> Parser(
+      createMCAsmParser(SrcMgr, MCCtx, Streamer, *MAI));
+
+  MCTargetOptions MCOptions;
+  std::unique_ptr<MCTargetAsmParser> TAP(
+      T->createMCAsmParser(*STI, *Parser, *MCII, MCOptions));
+  if (!TAP)
+    return;
+
+  Parser->setTargetParser(*TAP);
+  if (Parser->Run(false))
+    return;
+
+  handleSymverAliases(M, Streamer);
+
+  for (auto &KV : Streamer) {
+    StringRef Key = KV.first();
+    RecordStreamer::State Value = KV.second;
+    // FIXME: For now we just assume that all asm symbols are executable.
+    uint32_t Res = BasicSymbolRef::SF_Executable;
+    switch (Value) {
+    case RecordStreamer::NeverSeen:
+      llvm_unreachable("NeverSeen should have been replaced earlier");
+    case RecordStreamer::DefinedGlobal:
+      Res |= BasicSymbolRef::SF_Global;
+      break;
+    case RecordStreamer::Defined:
+      break;
+    case RecordStreamer::Global:
+    case RecordStreamer::Used:
+      Res |= BasicSymbolRef::SF_Undefined;
+      Res |= BasicSymbolRef::SF_Global;
+      break;
+    case RecordStreamer::DefinedWeak:
+      Res |= BasicSymbolRef::SF_Weak;
+      Res |= BasicSymbolRef::SF_Global;
+      break;
+    case RecordStreamer::UndefinedWeak:
+      Res |= BasicSymbolRef::SF_Weak;
+      Res |= BasicSymbolRef::SF_Undefined;
+    }
+    AsmSymbol(Key, BasicSymbolRef::Flags(Res));
+  }
+}
+
+void ModuleSymbolTable::printSymbolName(raw_ostream &OS, Symbol S) const {
+  if (S.is<AsmSymbol *>()) {
+    OS << S.get<AsmSymbol *>()->first;
+    return;
+  }
+
+  auto *GV = S.get<GlobalValue *>();
+  if (GV->hasDLLImportStorageClass())
+    OS << "__imp_";
+
+  Mang.getNameWithPrefix(OS, GV, false);
+}
+
+uint32_t ModuleSymbolTable::getSymbolFlags(Symbol S) const {
+  if (S.is<AsmSymbol *>())
+    return S.get<AsmSymbol *>()->second;
+
+  auto *GV = S.get<GlobalValue *>();
+
+  uint32_t Res = BasicSymbolRef::SF_None;
+  if (GV->isDeclarationForLinker())
+    Res |= BasicSymbolRef::SF_Undefined;
+  else if (GV->hasHiddenVisibility() && !GV->hasLocalLinkage())
+    Res |= BasicSymbolRef::SF_Hidden;
+  if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV)) {
+    if (GVar->isConstant())
+      Res |= BasicSymbolRef::SF_Const;
+  }
+  if (dyn_cast_or_null<Function>(GV->getBaseObject()))
+    Res |= BasicSymbolRef::SF_Executable;
+  if (isa<GlobalAlias>(GV))
+    Res |= BasicSymbolRef::SF_Indirect;
+  if (GV->hasPrivateLinkage())
+    Res |= BasicSymbolRef::SF_FormatSpecific;
+  if (!GV->hasLocalLinkage())
+    Res |= BasicSymbolRef::SF_Global;
+  if (GV->hasCommonLinkage())
+    Res |= BasicSymbolRef::SF_Common;
+  if (GV->hasLinkOnceLinkage() || GV->hasWeakLinkage() ||
+      GV->hasExternalWeakLinkage())
+    Res |= BasicSymbolRef::SF_Weak;
+
+  if (GV->getName().startswith("llvm."))
+    Res |= BasicSymbolRef::SF_FormatSpecific;
+  else if (auto *Var = dyn_cast<GlobalVariable>(GV)) {
+    if (Var->getSection() == "llvm.metadata")
+      Res |= BasicSymbolRef::SF_FormatSpecific;
+  }
+
+  return Res;
+}