llvm/tools/dsymutil/BinaryHolder.h

   1 //===-- BinaryHolder.h - Utility class for accessing binaries -------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This program is a utility that aims to be a dropin replacement for
  10 // Darwin's dsymutil.
  11 //
  12 //===----------------------------------------------------------------------===//
  13 #ifndef LLVM_TOOLS_DSYMUTIL_BINARYHOLDER_H
  14 #define LLVM_TOOLS_DSYMUTIL_BINARYHOLDER_H
  15
  16 #include "llvm/ADT/DenseMap.h"
  17 #include "llvm/ADT/StringMap.h"
  18 #include "llvm/ADT/Triple.h"
  19 #include "llvm/Object/Archive.h"
  20 #include "llvm/Object/Error.h"
  21 #include "llvm/Object/MachOUniversal.h"
  22 #include "llvm/Object/ObjectFile.h"
  23 #include "llvm/Support/Chrono.h"
  24 #include "llvm/Support/Errc.h"
  25 #include "llvm/Support/ErrorOr.h"
  26 #include "llvm/Support/VirtualFileSystem.h"
  27
  28 #include <mutex>
  29
  30 namespace llvm {
  31 namespace dsymutil {
  32
  33 /// The BinaryHolder class is responsible for creating and owning
  34 /// ObjectFiles and their underlying MemoryBuffers. It differs from a simple
  35 /// OwningBinary in that it handles accessing and caching of archives and its
  36 /// members.
  37 class BinaryHolder {
  38 public:
  39   using TimestampTy = sys::TimePoint<std::chrono::seconds>;
  40
  41   BinaryHolder(IntrusiveRefCntPtr<vfs::FileSystem> VFS, bool Verbose = false)
  42       : VFS(VFS), Verbose(Verbose) {}
  43
  44   // Forward declarations for friend declaration.
  45   class ObjectEntry;
  46   class ArchiveEntry;
  47
  48   /// Base class shared by cached entries, representing objects and archives.
  49   class EntryBase {
  50   protected:
  51     std::unique_ptr<MemoryBuffer> MemBuffer;
  52     std::unique_ptr<object::MachOUniversalBinary> FatBinary;
  53     std::string FatBinaryName;
  54   };
  55
  56   /// Cached entry holding one or more (in case of a fat binary) object files.
  57   class ObjectEntry : public EntryBase {
  58   public:
  59     /// Load the given object binary in memory.
  60     Error load(IntrusiveRefCntPtr<vfs::FileSystem> VFS, StringRef Filename,
  61                TimestampTy Timestamp, bool Verbose = false);
  62
  63     /// Access all owned ObjectFiles.
  64     std::vector<const object::ObjectFile *> getObjects() const;
  65
  66     /// Access to a derived version of all the currently owned ObjectFiles. The
  67     /// conversion might be invalid, in which case an Error is returned.
  68     template <typename ObjectFileType>
  69     Expected<std::vector<const ObjectFileType *>> getObjectsAs() const {
  70       std::vector<const ObjectFileType *> Result;
  71       Result.reserve(Objects.size());
  72       for (auto &Object : Objects) {
  73         const auto *Derived = dyn_cast<ObjectFileType>(Object.get());
  74         if (!Derived)
  75           return errorCodeToError(object::object_error::invalid_file_type);
  76         Result.push_back(Derived);
  77       }
  78       return Result;
  79     }
  80
  81     /// Access the owned ObjectFile with architecture \p T.
  82     Expected<const object::ObjectFile &> getObject(const Triple &T) const;
  83
  84     /// Access to a derived version of the currently owned ObjectFile with
  85     /// architecture \p T. The conversion must be known to be valid.
  86     template <typename ObjectFileType>
  87     Expected<const ObjectFileType &> getObjectAs(const Triple &T) const {
  88       auto Object = getObject(T);
  89       if (!Object)
  90         return Object.takeError();
  91       return cast<ObjectFileType>(*Object);
  92     }
  93
  94   private:
  95     std::vector<std::unique_ptr<object::ObjectFile>> Objects;
  96     friend ArchiveEntry;
  97   };
  98
  99   /// Cached entry holding one or more (in the of a fat binary) archive files.
 100   class ArchiveEntry : public EntryBase {
 101   public:
 102     struct KeyTy {
 103       std::string Filename;
 104       TimestampTy Timestamp;
 105
 106       KeyTy() {}
 107       KeyTy(StringRef Filename, TimestampTy Timestamp)
 108           : Filename(Filename.str()), Timestamp(Timestamp) {}
 109     };
 110
 111     /// Load the given object binary in memory.
 112     Error load(IntrusiveRefCntPtr<vfs::FileSystem> VFS, StringRef Filename,
 113                TimestampTy Timestamp, bool Verbose = false);
 114
 115     Expected<const ObjectEntry &> getObjectEntry(StringRef Filename,
 116                                                  TimestampTy Timestamp,
 117                                                  bool Verbose = false);
 118
 119   private:
 120     std::vector<std::unique_ptr<object::Archive>> Archives;
 121     DenseMap<KeyTy, std::unique_ptr<ObjectEntry>> MemberCache;
 122     std::mutex MemberCacheMutex;
 123   };
 124
 125   Expected<const ObjectEntry &>
 126   getObjectEntry(StringRef Filename, TimestampTy Timestamp = TimestampTy());
 127
 128   void clear();
 129
 130 private:
 131   /// Cache of static archives. Objects that are part of a static archive are
 132   /// stored under this object, rather than in the map below.
 133   StringMap<std::unique_ptr<ArchiveEntry>> ArchiveCache;
 134   std::mutex ArchiveCacheMutex;
 135
 136   /// Object entries for objects that are not in a static archive.
 137   StringMap<std::unique_ptr<ObjectEntry>> ObjectCache;
 138   std::mutex ObjectCacheMutex;
 139
 140   /// Virtual File System instance.
 141   IntrusiveRefCntPtr<vfs::FileSystem> VFS;
 142
 143   bool Verbose;
 144 };
 145
 146 } // namespace dsymutil
 147
 148 template <> struct DenseMapInfo<dsymutil::BinaryHolder::ArchiveEntry::KeyTy> {
 149
 150   static inline dsymutil::BinaryHolder::ArchiveEntry::KeyTy getEmptyKey() {
 151     return dsymutil::BinaryHolder::ArchiveEntry::KeyTy();
 152   }
 153
 154   static inline dsymutil::BinaryHolder::ArchiveEntry::KeyTy getTombstoneKey() {
 155     return dsymutil::BinaryHolder::ArchiveEntry::KeyTy("/", {});
 156   }
 157
 158   static unsigned
 159   getHashValue(const dsymutil::BinaryHolder::ArchiveEntry::KeyTy &K) {
 160     return hash_combine(DenseMapInfo<StringRef>::getHashValue(K.Filename),
 161                         DenseMapInfo<unsigned>::getHashValue(
 162                             K.Timestamp.time_since_epoch().count()));
 163   }
 164
 165   static bool isEqual(const dsymutil::BinaryHolder::ArchiveEntry::KeyTy &LHS,
 166                       const dsymutil::BinaryHolder::ArchiveEntry::KeyTy &RHS) {
 167     return LHS.Filename == RHS.Filename && LHS.Timestamp == RHS.Timestamp;
 168   }
 169 };
 170
 171 } // namespace llvm
 172 #endif