MetadataLoader.h

//===-- Bitcode/Reader/MetadataLoader.h - Load Metadatas -------*- C++ -*-====//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This class handles loading Metadatas.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_LIB_BITCODE_READER_METADATALOADER_H
#define LLVM_LIB_BITCODE_READER_METADATALOADER_H

#include "llvm/Support/Error.h"

#include <functional>
#include <memory>

namespace llvm {
class BasicBlock;
class BitcodeReaderValueList;
class BitstreamCursor;
class DISubprogram;
class Function;
class Instruction;
class Metadata;
class Module;
class Type;
template <typename T> class ArrayRef;

typedef std::function<Type *(unsigned)> GetTypeByIDTy;

typedef std::function<unsigned(unsigned, unsigned)> GetContainedTypeIDTy;

typedef std::function<void(Metadata **, unsigned, GetTypeByIDTy,
                           GetContainedTypeIDTy)>
    MDTypeCallbackTy;

struct MetadataLoaderCallbacks {
  GetTypeByIDTy GetTypeByID;
  GetContainedTypeIDTy GetContainedTypeID;
  std::optional<MDTypeCallbackTy> MDType;
};

/// Helper class that handles loading Metadatas and keeping them available.
class MetadataLoader {
  class MetadataLoaderImpl;
  std::unique_ptr<MetadataLoaderImpl> Pimpl;
  Error parseMetadata(bool ModuleLevel);

public:
  ~MetadataLoader();
  MetadataLoader(BitstreamCursor &Stream, Module &TheModule,
                 BitcodeReaderValueList &ValueList, bool IsImporting,
                 MetadataLoaderCallbacks Callbacks);
  MetadataLoader &operator=(MetadataLoader &&);
  MetadataLoader(MetadataLoader &&);

  // Parse a module metadata block
  Error parseModuleMetadata() { return parseMetadata(true); }

  // Parse a function metadata block
  Error parseFunctionMetadata() { return parseMetadata(false); }

  /// Set the mode to strip TBAA metadata on load.
  void setStripTBAA(bool StripTBAA = true);

  /// Return true if the Loader is stripping TBAA metadata.
  bool isStrippingTBAA();

  // Return true there are remaining unresolved forward references.
  bool hasFwdRefs() const;

  /// Return the given metadata, creating a replaceable forward reference if
  /// necessary.
  Metadata *getMetadataFwdRefOrLoad(unsigned Idx);

  /// Return the DISubprogram metadata for a Function if any, null otherwise.
  DISubprogram *lookupSubprogramForFunction(Function *F);

  /// Parse a `METADATA_ATTACHMENT` block for a function.
  Error parseMetadataAttachment(Function &F,
                                ArrayRef<Instruction *> InstructionList);

  /// Parse a `METADATA_KIND` block for the current module.
  Error parseMetadataKinds();

  unsigned size() const;
  void shrinkTo(unsigned N);

  /// Perform bitcode upgrades on llvm.dbg.* calls.
  void upgradeDebugIntrinsics(Function &F);
};
}

#endif // LLVM_LIB_BITCODE_READER_METADATALOADER_H