예제 #1
0
extern "C" void
LLVMRustSetDLLExportStorageClass(LLVMValueRef Value) {
    GlobalValue *V = unwrap<GlobalValue>(Value);
    V->setDLLStorageClass(GlobalValue::DLLExportStorageClass);
}
void FunctionImportGlobalProcessing::processGlobalForThinLTO(GlobalValue &GV) {

  ValueInfo VI;
  if (GV.hasName()) {
    VI = ImportIndex.getValueInfo(GV.getGUID());
    // Set synthetic function entry counts.
    if (VI && ImportIndex.hasSyntheticEntryCounts()) {
      if (Function *F = dyn_cast<Function>(&GV)) {
        if (!F->isDeclaration()) {
          for (auto &S : VI.getSummaryList()) {
            FunctionSummary *FS = dyn_cast<FunctionSummary>(S->getBaseObject());
            if (FS->modulePath() == M.getModuleIdentifier()) {
              F->setEntryCount(Function::ProfileCount(FS->entryCount(),
                                                      Function::PCT_Synthetic));
              break;
            }
          }
        }
      }
    }
    // Check the summaries to see if the symbol gets resolved to a known local
    // definition.
    if (VI && VI.isDSOLocal()) {
      GV.setDSOLocal(true);
      if (GV.hasDLLImportStorageClass())
        GV.setDLLStorageClass(GlobalValue::DefaultStorageClass);
    }
  }

  // Mark read-only variables which can be imported with specific attribute.
  // We can't internalize them now because IRMover will fail to link variable
  // definitions to their external declarations during ThinLTO import. We'll
  // internalize read-only variables later, after import is finished.
  // See internalizeImmutableGVs.
  //
  // If global value dead stripping is not enabled in summary then
  // propagateConstants hasn't been run. We can't internalize GV
  // in such case.
  if (!GV.isDeclaration() && VI && ImportIndex.withGlobalValueDeadStripping()) {
    const auto &SL = VI.getSummaryList();
    auto *GVS = SL.empty() ? nullptr : dyn_cast<GlobalVarSummary>(SL[0].get());
    if (GVS && GVS->isReadOnly())
      cast<GlobalVariable>(&GV)->addAttribute("thinlto-internalize");
  }

  bool DoPromote = false;
  if (GV.hasLocalLinkage() &&
      ((DoPromote = shouldPromoteLocalToGlobal(&GV)) || isPerformingImport())) {
    // Save the original name string before we rename GV below.
    auto Name = GV.getName().str();
    // Once we change the name or linkage it is difficult to determine
    // again whether we should promote since shouldPromoteLocalToGlobal needs
    // to locate the summary (based on GUID from name and linkage). Therefore,
    // use DoPromote result saved above.
    GV.setName(getName(&GV, DoPromote));
    GV.setLinkage(getLinkage(&GV, DoPromote));
    if (!GV.hasLocalLinkage())
      GV.setVisibility(GlobalValue::HiddenVisibility);

    // If we are renaming a COMDAT leader, ensure that we record the COMDAT
    // for later renaming as well. This is required for COFF.
    if (const auto *C = GV.getComdat())
      if (C->getName() == Name)
        RenamedComdats.try_emplace(C, M.getOrInsertComdat(GV.getName()));
  } else
    GV.setLinkage(getLinkage(&GV, /* DoPromote */ false));

  // Remove functions imported as available externally defs from comdats,
  // as this is a declaration for the linker, and will be dropped eventually.
  // It is illegal for comdats to contain declarations.
  auto *GO = dyn_cast<GlobalObject>(&GV);
  if (GO && GO->isDeclarationForLinker() && GO->hasComdat()) {
    // The IRMover should not have placed any imported declarations in
    // a comdat, so the only declaration that should be in a comdat
    // at this point would be a definition imported as available_externally.
    assert(GO->hasAvailableExternallyLinkage() &&
           "Expected comdat on definition (possibly available external)");
    GO->setComdat(nullptr);
  }
}