Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

//===- llvm/Bitcode/BitcodeReader.h - Bitcode reader ------------*- 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 header defines interfaces to read LLVM bitcode files/streams.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_BITCODE_BITCODEREADER_H

#define LLVM_BITCODE_BITCODEREADER_H

#include "llvm/ADT/ArrayRef.h"

#include "llvm/ADT/StringRef.h"

#include "llvm/Bitstream/BitCodeEnums.h"

#include "llvm/IR/GlobalValue.h"

#include "llvm/Support/Endian.h"

#include "llvm/Support/Error.h"

#include "llvm/Support/ErrorOr.h"

#include "llvm/Support/MemoryBufferRef.h"

#include <cstdint>

#include <memory>

#include <optional>

#include <string>

#include <system_error>

#include <vector>

namespace llvm {

class LLVMContext;

class Module;

class MemoryBuffer;

class Metadata;

class ModuleSummaryIndex;

class Type;

class Value;

// Callback to override the data layout string of an imported bitcode module.

// The first argument is the target triple, the second argument the data layout

// string from the input, or a default string. It will be used if the callback

// returns std::nullopt.

typedef std::function<std::optional<std::string>(StringRef, StringRef)>

    DataLayoutCallbackFuncTy;

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

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

typedef std::function<void(Value *, unsigned, GetTypeByIDTy,

                           GetContainedTypeIDTy)>

    ValueTypeCallbackTy;

typedef std::function<void(Metadata **, unsigned, GetTypeByIDTy,

                           GetContainedTypeIDTy)>

    MDTypeCallbackTy;

// These functions are for converting Expected/Error values to

// ErrorOr/std::error_code for compatibility with legacy clients. FIXME:

// Remove these functions once no longer needed by the C and libLTO APIs.

std::error_code errorToErrorCodeAndEmitErrors(LLVMContext &Ctx, Error Err);

template <typename T>

ErrorOr<T> expectedToErrorOrAndEmitErrors(LLVMContext &Ctx, Expected<T> Val) {

  if (!Val)

    return errorToErrorCodeAndEmitErrors(Ctx, Val.takeError());

  return std::move(*Val);

}

struct ParserCallbacks {

  std::optional<DataLayoutCallbackFuncTy> DataLayout;

  /// The ValueType callback is called for every function definition or

  /// declaration and allows accessing the type information, also behind

  /// pointers. This can be useful, when the opaque pointer upgrade cleans all

  /// type information behind pointers.

  /// The second argument to ValueTypeCallback is the type ID of the

  /// function, the two passed functions can be used to extract type

  /// information.

  std::optional<ValueTypeCallbackTy> ValueType;

  /// The MDType callback is called for every value in metadata.

  std::optional<MDTypeCallbackTy> MDType;

  ParserCallbacks() = default;

  explicit ParserCallbacks(DataLayoutCallbackFuncTy DataLayout)

      : DataLayout(DataLayout) {}

};

  struct BitcodeFileContents;

  /// Basic information extracted from a bitcode module to be used for LTO.

  struct BitcodeLTOInfo {

    bool IsThinLTO;

    bool HasSummary;

    bool EnableSplitLTOUnit;

  };

  /// Represents a module in a bitcode file.

  class BitcodeModule {

    // This covers the identification (if present) and module blocks.

    ArrayRef<uint8_t> Buffer;

    StringRef ModuleIdentifier;

    // The string table used to interpret this module.

    StringRef Strtab;

    // The bitstream location of the IDENTIFICATION_BLOCK.

    uint64_t IdentificationBit;

    // The bitstream location of this module's MODULE_BLOCK.

    uint64_t ModuleBit;

    BitcodeModule(ArrayRef<uint8_t> Buffer, StringRef ModuleIdentifier,

                  uint64_t IdentificationBit, uint64_t ModuleBit)

        : Buffer(Buffer), ModuleIdentifier(ModuleIdentifier),

          IdentificationBit(IdentificationBit), ModuleBit(ModuleBit) {}

    // Calls the ctor.

    friend Expected<BitcodeFileContents>

    getBitcodeFileContents(MemoryBufferRef Buffer);

    Expected<std::unique_ptr<Module>>

    getModuleImpl(LLVMContext &Context, bool MaterializeAll,

                  bool ShouldLazyLoadMetadata, bool IsImporting,

                  ParserCallbacks Callbacks = {});

  public:

    StringRef getBuffer() const {

      return StringRef((const char *)Buffer.begin(), Buffer.size());

    }

    StringRef getStrtab() const { return Strtab; }

    StringRef getModuleIdentifier() const { return ModuleIdentifier; }

    /// Read the bitcode module and prepare for lazy deserialization of function

    /// bodies. If ShouldLazyLoadMetadata is true, lazily load metadata as well.

    /// If IsImporting is true, this module is being parsed for ThinLTO

    /// importing into another module.

    Expected<std::unique_ptr<Module>>

    getLazyModule(LLVMContext &Context, bool ShouldLazyLoadMetadata,

                  bool IsImporting, ParserCallbacks Callbacks = {});

    /// Read the entire bitcode module and return it.

    Expected<std::unique_ptr<Module>>

    parseModule(LLVMContext &Context, ParserCallbacks Callbacks = {});

    /// Returns information about the module to be used for LTO: whether to

    /// compile with ThinLTO, and whether it has a summary.

    Expected<BitcodeLTOInfo> getLTOInfo();

    /// Parse the specified bitcode buffer, returning the module summary index.

    Expected<std::unique_ptr<ModuleSummaryIndex>> getSummary();

    /// Parse the specified bitcode buffer and merge its module summary index

    /// into CombinedIndex.

    Error

    readSummary(ModuleSummaryIndex &CombinedIndex, StringRef ModulePath,

                uint64_t ModuleId,

                std::function<bool(GlobalValue::GUID)> IsPrevailing = nullptr);

  };

  struct BitcodeFileContents {

    std::vector<BitcodeModule> Mods;

    StringRef Symtab, StrtabForSymtab;

  };

  /// Returns the contents of a bitcode file. This includes the raw contents of

  /// the symbol table embedded in the bitcode file. Clients which require a

  /// symbol table should prefer to use irsymtab::read instead of this function

  /// because it creates a reader for the irsymtab and handles upgrading bitcode

  /// files without a symbol table or with an old symbol table.

  Expected<BitcodeFileContents> getBitcodeFileContents(MemoryBufferRef Buffer);

  /// Returns a list of modules in the specified bitcode buffer.

  Expected<std::vector<BitcodeModule>>

  getBitcodeModuleList(MemoryBufferRef Buffer);

  /// Read the header of the specified bitcode buffer and prepare for lazy

  /// deserialization of function bodies. If ShouldLazyLoadMetadata is true,

  /// lazily load metadata as well. If IsImporting is true, this module is

  /// being parsed for ThinLTO importing into another module.

  Expected<std::unique_ptr<Module>>

  getLazyBitcodeModule(MemoryBufferRef Buffer, LLVMContext &Context,

                       bool ShouldLazyLoadMetadata = false,

                       bool IsImporting = false,

                       ParserCallbacks Callbacks = {});

  /// Like getLazyBitcodeModule, except that the module takes ownership of

  /// the memory buffer if successful. If successful, this moves Buffer. On

  /// error, this *does not* move Buffer. If IsImporting is true, this module is

  /// being parsed for ThinLTO importing into another module.

  Expected<std::unique_ptr<Module>> getOwningLazyBitcodeModule(

      std::unique_ptr<MemoryBuffer> &&Buffer, LLVMContext &Context,

      bool ShouldLazyLoadMetadata = false, bool IsImporting = false,

      ParserCallbacks Callbacks = {});

  /// Read the header of the specified bitcode buffer and extract just the

  /// triple information. If successful, this returns a string. On error, this

  /// returns "".

  Expected<std::string> getBitcodeTargetTriple(MemoryBufferRef Buffer);

  /// Return true if \p Buffer contains a bitcode file with ObjC code (category

  /// or class) in it.

  Expected<bool> isBitcodeContainingObjCCategory(MemoryBufferRef Buffer);

  /// Read the header of the specified bitcode buffer and extract just the

  /// producer string information. If successful, this returns a string. On

  /// error, this returns "".

  Expected<std::string> getBitcodeProducerString(MemoryBufferRef Buffer);

  /// Read the specified bitcode file, returning the module.

  Expected<std::unique_ptr<Module>>

  parseBitcodeFile(MemoryBufferRef Buffer, LLVMContext &Context,

                   ParserCallbacks Callbacks = {});

  /// Returns LTO information for the specified bitcode file.

  Expected<BitcodeLTOInfo> getBitcodeLTOInfo(MemoryBufferRef Buffer);

  /// Parse the specified bitcode buffer, returning the module summary index.

  Expected<std::unique_ptr<ModuleSummaryIndex>>

  getModuleSummaryIndex(MemoryBufferRef Buffer);

  /// Parse the specified bitcode buffer and merge the index into CombinedIndex.

  Error readModuleSummaryIndex(MemoryBufferRef Buffer,

                               ModuleSummaryIndex &CombinedIndex,

                               uint64_t ModuleId);

  /// Parse the module summary index out of an IR file and return the module

  /// summary index object if found, or an empty summary if not. If Path refers

  /// to an empty file and IgnoreEmptyThinLTOIndexFile is true, then

  /// this function will return nullptr.

  Expected<std::unique_ptr<ModuleSummaryIndex>>

  getModuleSummaryIndexForFile(StringRef Path,

                               bool IgnoreEmptyThinLTOIndexFile = false);

  /// isBitcodeWrapper - Return true if the given bytes are the magic bytes

  /// for an LLVM IR bitcode wrapper.

  inline bool isBitcodeWrapper(const unsigned char *BufPtr,

                               const unsigned char *BufEnd) {

    // See if you can find the hidden message in the magic bytes :-).

    // (Hint: it's a little-endian encoding.)

    return BufPtr != BufEnd &&

           BufPtr[0] == 0xDE &&

           BufPtr[1] == 0xC0 &&

           BufPtr[2] == 0x17 &&

           BufPtr[3] == 0x0B;

  }

  /// isRawBitcode - Return true if the given bytes are the magic bytes for

  /// raw LLVM IR bitcode (without a wrapper).

  inline bool isRawBitcode(const unsigned char *BufPtr,

                           const unsigned char *BufEnd) {

    // These bytes sort of have a hidden message, but it's not in

    // little-endian this time, and it's a little redundant.

    return BufPtr != BufEnd &&

           BufPtr[0] == 'B' &&

           BufPtr[1] == 'C' &&

           BufPtr[2] == 0xc0 &&

           BufPtr[3] == 0xde;

  }

  /// isBitcode - Return true if the given bytes are the magic bytes for

  /// LLVM IR bitcode, either with or without a wrapper.

  inline bool isBitcode(const unsigned char *BufPtr,

                        const unsigned char *BufEnd) {

    return isBitcodeWrapper(BufPtr, BufEnd) ||

           isRawBitcode(BufPtr, BufEnd);

  }

  /// SkipBitcodeWrapperHeader - Some systems wrap bc files with a special

  /// header for padding or other reasons.  The format of this header is:

  ///

  /// struct bc_header {

  ///   uint32_t Magic;         // 0x0B17C0DE

  ///   uint32_t Version;       // Version, currently always 0.

  ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.

  ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.

  ///   ... potentially other gunk ...

  /// };

  ///

  /// This function is called when we find a file with a matching magic number.

  /// In this case, skip down to the subsection of the file that is actually a

  /// BC file.

  /// If 'VerifyBufferSize' is true, check that the buffer is large enough to

  /// contain the whole bitcode file.

  inline bool SkipBitcodeWrapperHeader(const unsigned char *&BufPtr,

                                       const unsigned char *&BufEnd,

                                       bool VerifyBufferSize) {

    // Must contain the offset and size field!

    if (unsigned(BufEnd - BufPtr) < BWH_SizeField + 4)

      return true;

    unsigned Offset = support::endian::read32le(&BufPtr[BWH_OffsetField]);

    unsigned Size = support::endian::read32le(&BufPtr[BWH_SizeField]);

    uint64_t BitcodeOffsetEnd = (uint64_t)Offset + (uint64_t)Size;

    // Verify that Offset+Size fits in the file.

    if (VerifyBufferSize && BitcodeOffsetEnd > uint64_t(BufEnd-BufPtr))

      return true;

    BufPtr += Offset;

    BufEnd = BufPtr+Size;

    return false;

  }

  APInt readWideAPInt(ArrayRef<uint64_t> Vals, unsigned TypeBits);

  const std::error_category &BitcodeErrorCategory();

  enum class BitcodeError { CorruptedBitcode = 1 };

  inline std::error_code make_error_code(BitcodeError E) {

    return std::error_code(static_cast<int>(E), BitcodeErrorCategory());

  }

} // end namespace llvm

namespace std {

template <> struct is_error_code_enum<llvm::BitcodeError> : std::true_type {};

} // end namespace std

#endif // LLVM_BITCODE_BITCODEREADER_H