C++ GlobalValue::isDSOLocal方法代码示例

ModuleSummaryIndex llvm::buildModuleSummaryIndex(
    const Module &M,
    std::function<BlockFrequencyInfo *(const Function &F)> GetBFICallback,
    ProfileSummaryInfo *PSI) {
  assert(PSI);
  ModuleSummaryIndex Index(/*IsPerformingAnalysis=*/true);

  // Identify the local values in the llvm.used and llvm.compiler.used sets,
  // which should not be exported as they would then require renaming and
  // promotion, but we may have opaque uses e.g. in inline asm. We collect them
  // here because we use this information to mark functions containing inline
  // assembly calls as not importable.
  SmallPtrSet<GlobalValue *, 8> LocalsUsed;
  SmallPtrSet<GlobalValue *, 8> Used;
  // First collect those in the llvm.used set.
  collectUsedGlobalVariables(M, Used, /*CompilerUsed*/ false);
  // Next collect those in the llvm.compiler.used set.
  collectUsedGlobalVariables(M, Used, /*CompilerUsed*/ true);
  DenseSet<GlobalValue::GUID> CantBePromoted;
  for (auto *V : Used) {
    if (V->hasLocalLinkage()) {
      LocalsUsed.insert(V);
      CantBePromoted.insert(V->getGUID());
    }
  }

  bool HasLocalInlineAsmSymbol = false;
  if (!M.getModuleInlineAsm().empty()) {
    // Collect the local values defined by module level asm, and set up
    // summaries for these symbols so that they can be marked as NoRename,
    // to prevent export of any use of them in regular IR that would require
    // renaming within the module level asm. Note we don't need to create a
    // summary for weak or global defs, as they don't need to be flagged as
    // NoRename, and defs in module level asm can't be imported anyway.
    // Also, any values used but not defined within module level asm should
    // be listed on the llvm.used or llvm.compiler.used global and marked as
    // referenced from there.
    ModuleSymbolTable::CollectAsmSymbols(
        M, [&](StringRef Name, object::BasicSymbolRef::Flags Flags) {
          // Symbols not marked as Weak or Global are local definitions.
          if (Flags & (object::BasicSymbolRef::SF_Weak |
                       object::BasicSymbolRef::SF_Global))
            return;
          HasLocalInlineAsmSymbol = true;
          GlobalValue *GV = M.getNamedValue(Name);
          if (!GV)
            return;
          assert(GV->isDeclaration() && "Def in module asm already has definition");
          GlobalValueSummary::GVFlags GVFlags(GlobalValue::InternalLinkage,
                                              /* NotEligibleToImport = */ true,
                                              /* Live = */ true,
                                              /* Local */ GV->isDSOLocal());
          CantBePromoted.insert(GlobalValue::getGUID(Name));
          // Create the appropriate summary type.
          if (Function *F = dyn_cast<Function>(GV)) {
            std::unique_ptr<FunctionSummary> Summary =
                llvm::make_unique<FunctionSummary>(
                    GVFlags, 0,
                    FunctionSummary::FFlags{
                        F->hasFnAttribute(Attribute::ReadNone),
                        F->hasFnAttribute(Attribute::ReadOnly),
                        F->hasFnAttribute(Attribute::NoRecurse),
                        F->returnDoesNotAlias()},
                    ArrayRef<ValueInfo>{}, ArrayRef<FunctionSummary::EdgeTy>{},
                    ArrayRef<GlobalValue::GUID>{},
                    ArrayRef<FunctionSummary::VFuncId>{},
                    ArrayRef<FunctionSummary::VFuncId>{},
                    ArrayRef<FunctionSummary::ConstVCall>{},
                    ArrayRef<FunctionSummary::ConstVCall>{});
            Index.addGlobalValueSummary(Name, std::move(Summary));
          } else {
            std::unique_ptr<GlobalVarSummary> Summary =
                llvm::make_unique<GlobalVarSummary>(GVFlags,
                                                    ArrayRef<ValueInfo>{});
            Index.addGlobalValueSummary(Name, std::move(Summary));
          }
        });
  }

  // Compute summaries for all functions defined in module, and save in the
  // index.
  for (auto &F : M) {
    if (F.isDeclaration())
      continue;

    BlockFrequencyInfo *BFI = nullptr;
    std::unique_ptr<BlockFrequencyInfo> BFIPtr;
    if (GetBFICallback)
      BFI = GetBFICallback(F);
    else if (F.hasProfileData()) {
      LoopInfo LI{DominatorTree(const_cast<Function &>(F))};
      BranchProbabilityInfo BPI{F, LI};
      BFIPtr = llvm::make_unique<BlockFrequencyInfo>(F, BPI, LI);
      BFI = BFIPtr.get();
    }

    computeFunctionSummary(Index, M, F, BFI, PSI,
                           !LocalsUsed.empty() || HasLocalInlineAsmSymbol,
                           CantBePromoted);
  }
//.........这里部分代码省略.........