LCOV - code coverage report
Current view: top level - include/llvm/Bitcode - BitcodeReader.h (source / functions) Hit Total Coverage
Test: llvm-toolchain.info Lines: 29 29 100.0 %
Date: 2017-09-14 15:23:50 Functions: 3 3 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : //===- llvm/Bitcode/BitcodeReader.h - Bitcode reader ------------*- C++ -*-===//
       2             : //
       3             : //                     The LLVM Compiler Infrastructure
       4             : //
       5             : // This file is distributed under the University of Illinois Open Source
       6             : // License. See LICENSE.TXT for details.
       7             : //
       8             : //===----------------------------------------------------------------------===//
       9             : //
      10             : // This header defines interfaces to read LLVM bitcode files/streams.
      11             : //
      12             : //===----------------------------------------------------------------------===//
      13             : 
      14             : #ifndef LLVM_BITCODE_BITCODEREADER_H
      15             : #define LLVM_BITCODE_BITCODEREADER_H
      16             : 
      17             : #include "llvm/ADT/ArrayRef.h"
      18             : #include "llvm/ADT/StringRef.h"
      19             : #include "llvm/Bitcode/BitCodes.h"
      20             : #include "llvm/IR/ModuleSummaryIndex.h"
      21             : #include "llvm/Support/Endian.h"
      22             : #include "llvm/Support/Error.h"
      23             : #include "llvm/Support/ErrorOr.h"
      24             : #include "llvm/Support/MemoryBuffer.h"
      25             : #include <cstdint>
      26             : #include <memory>
      27             : #include <string>
      28             : #include <system_error>
      29             : #include <vector>
      30             : namespace llvm {
      31             : 
      32             : class LLVMContext;
      33             : class Module;
      34             : 
      35             :   // These functions are for converting Expected/Error values to
      36             :   // ErrorOr/std::error_code for compatibility with legacy clients. FIXME:
      37             :   // Remove these functions once no longer needed by the C and libLTO APIs.
      38             : 
      39             :   std::error_code errorToErrorCodeAndEmitErrors(LLVMContext &Ctx, Error Err);
      40             : 
      41             :   template <typename T>
      42         303 :   ErrorOr<T> expectedToErrorOrAndEmitErrors(LLVMContext &Ctx, Expected<T> Val) {
      43         303 :     if (!Val)
      44           6 :       return errorToErrorCodeAndEmitErrors(Ctx, Val.takeError());
      45         299 :     return std::move(*Val);
      46             :   }
      47             : 
      48             :   struct BitcodeFileContents;
      49             : 
      50             :   /// Basic information extracted from a bitcode module to be used for LTO.
      51             :   struct BitcodeLTOInfo {
      52             :     bool IsThinLTO;
      53             :     bool HasSummary;
      54             :   };
      55             : 
      56             :   /// Represents a module in a bitcode file.
      57             :   class BitcodeModule {
      58             :     // This covers the identification (if present) and module blocks.
      59             :     ArrayRef<uint8_t> Buffer;
      60             :     StringRef ModuleIdentifier;
      61             : 
      62             :     // The string table used to interpret this module.
      63             :     StringRef Strtab;
      64             : 
      65             :     // The bitstream location of the IDENTIFICATION_BLOCK.
      66             :     uint64_t IdentificationBit;
      67             : 
      68             :     // The bitstream location of this module's MODULE_BLOCK.
      69             :     uint64_t ModuleBit;
      70             : 
      71             :     BitcodeModule(ArrayRef<uint8_t> Buffer, StringRef ModuleIdentifier,
      72             :                   uint64_t IdentificationBit, uint64_t ModuleBit)
      73        3362 :         : Buffer(Buffer), ModuleIdentifier(ModuleIdentifier),
      74        6724 :           IdentificationBit(IdentificationBit), ModuleBit(ModuleBit) {}
      75             : 
      76             :     // Calls the ctor.
      77             :     friend Expected<BitcodeFileContents>
      78             :     getBitcodeFileContents(MemoryBufferRef Buffer);
      79             : 
      80             :     Expected<std::unique_ptr<Module>> getModuleImpl(LLVMContext &Context,
      81             :                                                     bool MaterializeAll,
      82             :                                                     bool ShouldLazyLoadMetadata,
      83             :                                                     bool IsImporting);
      84             : 
      85             :   public:
      86             :     StringRef getBuffer() const {
      87          64 :       return StringRef((const char *)Buffer.begin(), Buffer.size());
      88             :     }
      89             : 
      90             :     StringRef getStrtab() const { return Strtab; }
      91             : 
      92             :     StringRef getModuleIdentifier() const { return ModuleIdentifier; }
      93             : 
      94             :     /// Read the bitcode module and prepare for lazy deserialization of function
      95             :     /// bodies. If ShouldLazyLoadMetadata is true, lazily load metadata as well.
      96             :     /// If IsImporting is true, this module is being parsed for ThinLTO
      97             :     /// importing into another module.
      98             :     Expected<std::unique_ptr<Module>> getLazyModule(LLVMContext &Context,
      99             :                                                     bool ShouldLazyLoadMetadata,
     100             :                                                     bool IsImporting);
     101             : 
     102             :     /// Read the entire bitcode module and return it.
     103             :     Expected<std::unique_ptr<Module>> parseModule(LLVMContext &Context);
     104             : 
     105             :     /// Returns information about the module to be used for LTO: whether to
     106             :     /// compile with ThinLTO, and whether it has a summary.
     107             :     Expected<BitcodeLTOInfo> getLTOInfo();
     108             : 
     109             :     /// Parse the specified bitcode buffer, returning the module summary index.
     110             :     Expected<std::unique_ptr<ModuleSummaryIndex>> getSummary();
     111             : 
     112             :     /// Parse the specified bitcode buffer and merge its module summary index
     113             :     /// into CombinedIndex.
     114             :     Error readSummary(ModuleSummaryIndex &CombinedIndex, StringRef ModulePath,
     115             :                       uint64_t ModuleId);
     116             :   };
     117             : 
     118       29768 :   struct BitcodeFileContents {
     119             :     std::vector<BitcodeModule> Mods;
     120             :     StringRef Symtab, StrtabForSymtab;
     121             :   };
     122             : 
     123             :   /// Returns the contents of a bitcode file. This includes the raw contents of
     124             :   /// the symbol table embedded in the bitcode file. Clients which require a
     125             :   /// symbol table should prefer to use irsymtab::read instead of this function
     126             :   /// because it creates a reader for the irsymtab and handles upgrading bitcode
     127             :   /// files without a symbol table or with an old symbol table.
     128             :   Expected<BitcodeFileContents> getBitcodeFileContents(MemoryBufferRef Buffer);
     129             : 
     130             :   /// Returns a list of modules in the specified bitcode buffer.
     131             :   Expected<std::vector<BitcodeModule>>
     132             :   getBitcodeModuleList(MemoryBufferRef Buffer);
     133             : 
     134             :   /// Read the header of the specified bitcode buffer and prepare for lazy
     135             :   /// deserialization of function bodies. If ShouldLazyLoadMetadata is true,
     136             :   /// lazily load metadata as well. If IsImporting is true, this module is
     137             :   /// being parsed for ThinLTO importing into another module.
     138             :   Expected<std::unique_ptr<Module>>
     139             :   getLazyBitcodeModule(MemoryBufferRef Buffer, LLVMContext &Context,
     140             :                        bool ShouldLazyLoadMetadata = false,
     141             :                        bool IsImporting = false);
     142             : 
     143             :   /// Like getLazyBitcodeModule, except that the module takes ownership of
     144             :   /// the memory buffer if successful. If successful, this moves Buffer. On
     145             :   /// error, this *does not* move Buffer. If IsImporting is true, this module is
     146             :   /// being parsed for ThinLTO importing into another module.
     147             :   Expected<std::unique_ptr<Module>> getOwningLazyBitcodeModule(
     148             :       std::unique_ptr<MemoryBuffer> &&Buffer, LLVMContext &Context,
     149             :       bool ShouldLazyLoadMetadata = false, bool IsImporting = false);
     150             : 
     151             :   /// Read the header of the specified bitcode buffer and extract just the
     152             :   /// triple information. If successful, this returns a string. On error, this
     153             :   /// returns "".
     154             :   Expected<std::string> getBitcodeTargetTriple(MemoryBufferRef Buffer);
     155             : 
     156             :   /// Return true if \p Buffer contains a bitcode file with ObjC code (category
     157             :   /// or class) in it.
     158             :   Expected<bool> isBitcodeContainingObjCCategory(MemoryBufferRef Buffer);
     159             : 
     160             :   /// Read the header of the specified bitcode buffer and extract just the
     161             :   /// producer string information. If successful, this returns a string. On
     162             :   /// error, this returns "".
     163             :   Expected<std::string> getBitcodeProducerString(MemoryBufferRef Buffer);
     164             : 
     165             :   /// Read the specified bitcode file, returning the module.
     166             :   Expected<std::unique_ptr<Module>> parseBitcodeFile(MemoryBufferRef Buffer,
     167             :                                                      LLVMContext &Context);
     168             : 
     169             :   /// Returns LTO information for the specified bitcode file.
     170             :   Expected<BitcodeLTOInfo> getBitcodeLTOInfo(MemoryBufferRef Buffer);
     171             : 
     172             :   /// Parse the specified bitcode buffer, returning the module summary index.
     173             :   Expected<std::unique_ptr<ModuleSummaryIndex>>
     174             :   getModuleSummaryIndex(MemoryBufferRef Buffer);
     175             : 
     176             :   /// Parse the specified bitcode buffer and merge the index into CombinedIndex.
     177             :   Error readModuleSummaryIndex(MemoryBufferRef Buffer,
     178             :                                ModuleSummaryIndex &CombinedIndex,
     179             :                                uint64_t ModuleId);
     180             : 
     181             :   /// Parse the module summary index out of an IR file and return the module
     182             :   /// summary index object if found, or an empty summary if not. If Path refers
     183             :   /// to an empty file and IgnoreEmptyThinLTOIndexFile is true, then
     184             :   /// this function will return nullptr.
     185             :   Expected<std::unique_ptr<ModuleSummaryIndex>>
     186             :   getModuleSummaryIndexForFile(StringRef Path,
     187             :                                bool IgnoreEmptyThinLTOIndexFile = false);
     188             : 
     189             :   /// isBitcodeWrapper - Return true if the given bytes are the magic bytes
     190             :   /// for an LLVM IR bitcode wrapper.
     191             :   inline bool isBitcodeWrapper(const unsigned char *BufPtr,
     192             :                                const unsigned char *BufEnd) {
     193             :     // See if you can find the hidden message in the magic bytes :-).
     194             :     // (Hint: it's a little-endian encoding.)
     195       29637 :     return BufPtr != BufEnd &&
     196       30030 :            BufPtr[0] == 0xDE &&
     197         786 :            BufPtr[1] == 0xC0 &&
     198       30441 :            BufPtr[2] == 0x17 &&
     199         393 :            BufPtr[3] == 0x0B;
     200             :   }
     201             : 
     202             :   /// isRawBitcode - Return true if the given bytes are the magic bytes for
     203             :   /// raw LLVM IR bitcode (without a wrapper).
     204             :   inline bool isRawBitcode(const unsigned char *BufPtr,
     205             :                            const unsigned char *BufEnd) {
     206             :     // These bytes sort of have a hidden message, but it's not in
     207             :     // little-endian this time, and it's a little redundant.
     208       26054 :     return BufPtr != BufEnd &&
     209       26465 :            BufPtr[0] == 'B' &&
     210         822 :            BufPtr[1] == 'C' &&
     211       26892 :            BufPtr[2] == 0xc0 &&
     212         411 :            BufPtr[3] == 0xde;
     213             :   }
     214             : 
     215             :   /// isBitcode - Return true if the given bytes are the magic bytes for
     216             :   /// LLVM IR bitcode, either with or without a wrapper.
     217       26117 :   inline bool isBitcode(const unsigned char *BufPtr,
     218             :                         const unsigned char *BufEnd) {
     219       26070 :     return isBitcodeWrapper(BufPtr, BufEnd) ||
     220       26117 :            isRawBitcode(BufPtr, BufEnd);
     221             :   }
     222             : 
     223             :   /// SkipBitcodeWrapperHeader - Some systems wrap bc files with a special
     224             :   /// header for padding or other reasons.  The format of this header is:
     225             :   ///
     226             :   /// struct bc_header {
     227             :   ///   uint32_t Magic;         // 0x0B17C0DE
     228             :   ///   uint32_t Version;       // Version, currently always 0.
     229             :   ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
     230             :   ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
     231             :   ///   ... potentially other gunk ...
     232             :   /// };
     233             :   ///
     234             :   /// This function is called when we find a file with a matching magic number.
     235             :   /// In this case, skip down to the subsection of the file that is actually a
     236             :   /// BC file.
     237             :   /// If 'VerifyBufferSize' is true, check that the buffer is large enough to
     238             :   /// contain the whole bitcode file.
     239             :   inline bool SkipBitcodeWrapperHeader(const unsigned char *&BufPtr,
     240             :                                        const unsigned char *&BufEnd,
     241             :                                        bool VerifyBufferSize) {
     242             :     // Must contain the offset and size field!
     243         346 :     if (unsigned(BufEnd - BufPtr) < BWH_SizeField + 4)
     244             :       return true;
     245             : 
     246         692 :     unsigned Offset = support::endian::read32le(&BufPtr[BWH_OffsetField]);
     247         692 :     unsigned Size = support::endian::read32le(&BufPtr[BWH_SizeField]);
     248         346 :     uint64_t BitcodeOffsetEnd = (uint64_t)Offset + (uint64_t)Size;
     249             : 
     250             :     // Verify that Offset+Size fits in the file.
     251         346 :     if (VerifyBufferSize && BitcodeOffsetEnd > uint64_t(BufEnd-BufPtr))
     252             :       return true;
     253         346 :     BufPtr += Offset;
     254         346 :     BufEnd = BufPtr+Size;
     255             :     return false;
     256             :   }
     257             : 
     258             :   const std::error_category &BitcodeErrorCategory();
     259             :   enum class BitcodeError { CorruptedBitcode = 1 };
     260             :   inline std::error_code make_error_code(BitcodeError E) {
     261          67 :     return std::error_code(static_cast<int>(E), BitcodeErrorCategory());
     262             :   }
     263             : 
     264             : } // end namespace llvm
     265             : 
     266             : namespace std {
     267             : 
     268             : template <> struct is_error_code_enum<llvm::BitcodeError> : std::true_type {};
     269             : 
     270             : } // end namespace std
     271             : 
     272             : #endif // LLVM_BITCODE_BITCODEREADER_H

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