[Object]

* Add begin_dynamic_table() / end_dynamic_table() private interface to ELFObjectFile.
* Add begin_libraries_needed() / end_libraries_needed() interface to ObjectFile, for grabbing the list of needed libraries for a shared object or dynamic executable.
* Implement this new interface completely for ELF, leave stubs for COFF and MachO.
* Add 'llvm-readobj' tool for dumping ObjectFile information.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151785 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 330 insertions, 1 deletions

diff --git a/include/llvm/Object/COFF.h b/include/llvm/Object/COFF.h
index 732141219e..6212785e3f 100644
--- a/include/llvm/Object/COFF.h
+++ b/include/llvm/Object/COFF.h
@@ -145,12 +145,19 @@ protected:
   virtual error_code getRelocationValueString(DataRefImpl Rel,
                                            SmallVectorImpl<char> &Result) const;
 
+  virtual error_code getLibraryNext(DataRefImpl LibData,
+                                    LibraryRef &Result) const;
+  virtual error_code getLibraryPath(DataRefImpl LibData,
+                                    StringRef &Result) const;
+
 public:
   COFFObjectFile(MemoryBuffer *Object, error_code &ec);
   virtual symbol_iterator begin_symbols() const;
   virtual symbol_iterator end_symbols() const;
   virtual symbol_iterator begin_dynamic_symbols() const;
   virtual symbol_iterator end_dynamic_symbols() const;
+  virtual library_iterator begin_libraries_needed() const;
+  virtual library_iterator end_libraries_needed() const;
   virtual section_iterator begin_sections() const;
   virtual section_iterator end_sections() const;
 
diff --git a/include/llvm/Object/ELF.h b/include/llvm/Object/ELF.h
index 6e3fa013af..ce002f2e4e 100644
--- a/include/llvm/Object/ELF.h
+++ b/include/llvm/Object/ELF.h
@@ -176,6 +176,71 @@ struct Elf_Sym_Impl : Elf_Sym_Base<target_endianness, is64Bits> {
   }
 };
 
+// Elf_Dyn: Entry in the dynamic table
+template<support::endianness target_endianness, bool is64Bits>
+struct Elf_Dyn_Base;
+
+template<support::endianness target_endianness>
+struct Elf_Dyn_Base<target_endianness, false> {
+  LLVM_ELF_IMPORT_TYPES(target_endianness, false)
+  Elf_Sword d_tag;
+  union {
+    Elf_Word d_val;
+    Elf_Addr d_ptr;
+  } d_un;
+};
+
+template<support::endianness target_endianness>
+struct Elf_Dyn_Base<target_endianness, true> {
+  LLVM_ELF_IMPORT_TYPES(target_endianness, true)
+  Elf_Sxword d_tag;
+  union {
+    Elf_Xword d_val;
+    Elf_Addr d_ptr;
+  } d_un;
+};
+
+template<support::endianness target_endianness, bool is64Bits>
+struct Elf_Dyn_Impl : Elf_Dyn_Base<target_endianness, is64Bits> {
+  using Elf_Dyn_Base<target_endianness, is64Bits>::d_tag;
+  using Elf_Dyn_Base<target_endianness, is64Bits>::d_un;
+  int64_t getTag() const { return d_tag; }
+  uint64_t getVal() const { return d_un.d_val; }
+  uint64_t getPtr() const { return d_un.ptr; }
+};
+
+template<support::endianness target_endianness, bool is64Bits>
+class ELFObjectFile;
+
+// DynRefImpl: Reference to an entry in the dynamic table
+// This is an ELF-specific interface.
+template<support::endianness target_endianness, bool is64Bits>
+class DynRefImpl {
+  typedef Elf_Dyn_Impl<target_endianness, is64Bits> Elf_Dyn;
+  typedef ELFObjectFile<target_endianness, is64Bits> OwningType;
+
+  DataRefImpl DynPimpl;
+  const OwningType *OwningObject;
+
+public:
+  DynRefImpl() : OwningObject(NULL) {
+    std::memset(&DynPimpl, 0, sizeof(DynPimpl));
+  }
+
+  DynRefImpl(DataRefImpl DynP, const OwningType *Owner);
+
+  bool operator==(const DynRefImpl &Other) const;
+  bool operator <(const DynRefImpl &Other) const;
+
+  error_code getNext(DynRefImpl &Result) const;
+  int64_t getTag() const;
+  uint64_t getVal() const;
+  uint64_t getPtr() const;
+
+  DataRefImpl getRawDataRefImpl() const;
+};
+
+// Elf_Rel: Elf Relocation
 template<support::endianness target_endianness, bool is64Bits, bool isRela>
 struct Elf_Rel_Base;
 
@@ -255,8 +320,11 @@ class ELFObjectFile : public ObjectFile {
 
   typedef Elf_Shdr_Impl<target_endianness, is64Bits> Elf_Shdr;
   typedef Elf_Sym_Impl<target_endianness, is64Bits> Elf_Sym;
+  typedef Elf_Dyn_Impl<target_endianness, is64Bits> Elf_Dyn;
   typedef Elf_Rel_Impl<target_endianness, is64Bits, false> Elf_Rel;
   typedef Elf_Rel_Impl<target_endianness, is64Bits, true> Elf_Rela;
+  typedef DynRefImpl<target_endianness, is64Bits> DynRef;
+  typedef content_iterator<DynRef> dyn_iterator;
 
 protected:
   struct Elf_Ehdr {
@@ -300,6 +368,8 @@ private:
   IndexMap_t SymbolTableSectionsIndexMap;
   DenseMap<const Elf_Sym*, ELF::Elf64_Word> ExtendedSymbolTable;
 
+  const Elf_Shdr *dot_dynamic_sec; // .dynamic
+
   /// @brief Map sections to an array of relocation sections that reference
   ///        them sorted by section index.
   RelocMap_t SectionRelocMap;
@@ -329,6 +399,9 @@ protected:
   const Elf_Sym  *getSymbol(DataRefImpl Symb) const; // FIXME: Should be private?
   void            validateSymbol(DataRefImpl Symb) const;
 
+public:
+  const Elf_Dyn  *getDyn(DataRefImpl DynData) const;
+
 protected:
   virtual error_code getSymbolNext(DataRefImpl Symb, SymbolRef &Res) const;
   virtual error_code getSymbolName(DataRefImpl Symb, StringRef &Res) const;
@@ -341,6 +414,12 @@ protected:
   virtual error_code getSymbolSection(DataRefImpl Symb,
                                       section_iterator &Res) const;
 
+  friend class DynRefImpl<target_endianness, is64Bits>;
+  virtual error_code getDynNext(DataRefImpl DynData, DynRef &Result) const;
+
+  virtual error_code getLibraryNext(DataRefImpl Data, LibraryRef &Result) const;
+  virtual error_code getLibraryPath(DataRefImpl Data, StringRef &Res) const;
+
   virtual error_code getSectionNext(DataRefImpl Sec, SectionRef &Res) const;
   virtual error_code getSectionName(DataRefImpl Sec, StringRef &Res) const;
   virtual error_code getSectionAddress(DataRefImpl Sec, uint64_t &Res) const;
@@ -376,11 +455,19 @@ public:
   ELFObjectFile(MemoryBuffer *Object, error_code &ec);
   virtual symbol_iterator begin_symbols() const;
   virtual symbol_iterator end_symbols() const;
+
   virtual symbol_iterator begin_dynamic_symbols() const;
   virtual symbol_iterator end_dynamic_symbols() const;
+
   virtual section_iterator begin_sections() const;
   virtual section_iterator end_sections() const;
 
+  virtual library_iterator begin_libraries_needed() const;
+  virtual library_iterator end_libraries_needed() const;
+
+  virtual dyn_iterator begin_dynamic_table() const;
+  virtual dyn_iterator end_dynamic_table() const;
+
   virtual uint8_t getBytesInAddress() const;
   virtual StringRef getFileFormatName() const;
   virtual unsigned getArch() const;
@@ -1171,7 +1258,8 @@ ELFObjectFile<target_endianness, is64Bits>::ELFObjectFile(MemoryBuffer *Object
   , SectionHeaderTable(0)
   , dot_shstrtab_sec(0)
   , dot_strtab_sec(0)
-  , dot_dynstr_sec(0) {
+  , dot_dynstr_sec(0)
+  , dot_dynamic_sec(0) {
 
   const uint64_t FileSize = Data->getBufferSize();
 
@@ -1227,6 +1315,12 @@ ELFObjectFile<target_endianness, is64Bits>::ELFObjectFile(MemoryBuffer *Object
     if (sh->sh_type == ELF::SHT_REL || sh->sh_type == ELF::SHT_RELA) {
       SectionRelocMap[getSection(sh->sh_info)].push_back(i);
     }
+    if (sh->sh_type == ELF::SHT_DYNAMIC) {
+      if (dot_dynamic_sec != NULL)
+        // FIXME: Proper error handling.
+        report_fatal_error("More than one .dynamic!");
+      dot_dynamic_sec = sh;
+    }
     ++sh;
   }
 
@@ -1353,6 +1447,121 @@ section_iterator ELFObjectFile<target_endianness, is64Bits>
 }
 
 template<support::endianness target_endianness, bool is64Bits>
+typename ELFObjectFile<target_endianness, is64Bits>::dyn_iterator
+ELFObjectFile<target_endianness, is64Bits>::begin_dynamic_table() const {
+  DataRefImpl DynData;
+  memset(&DynData, 0, sizeof(DynData));
+  if (dot_dynamic_sec == NULL || dot_dynamic_sec->sh_size == 0) {
+    DynData.d.a = std::numeric_limits<uint32_t>::max();
+  } else {
+    DynData.d.a = 0;
+  }
+  return dyn_iterator(DynRef(DynData, this));
+}
+
+template<support::endianness target_endianness, bool is64Bits>
+typename ELFObjectFile<target_endianness, is64Bits>::dyn_iterator
+ELFObjectFile<target_endianness, is64Bits>
+                          ::end_dynamic_table() const {
+  DataRefImpl DynData;
+  memset(&DynData, 0, sizeof(DynData));
+  DynData.d.a = std::numeric_limits<uint32_t>::max();
+  return dyn_iterator(DynRef(DynData, this));
+}
+
+template<support::endianness target_endianness, bool is64Bits>
+error_code ELFObjectFile<target_endianness, is64Bits>
+                        ::getDynNext(DataRefImpl DynData,
+                                     DynRef &Result) const {
+  ++DynData.d.a;
+
+  // Check to see if we are at the end of .dynamic
+  if (DynData.d.a >= dot_dynamic_sec->getEntityCount()) {
+    // We are at the end. Return the terminator.
+    DynData.d.a = std::numeric_limits<uint32_t>::max();
+  }
+
+  Result = DynRef(DynData, this);
+  return object_error::success;
+}
+
+template<support::endianness target_endianness, bool is64Bits>
+library_iterator ELFObjectFile<target_endianness, is64Bits>
+                             ::begin_libraries_needed() const {
+  // Find the first DT_NEEDED entry
+  dyn_iterator i = begin_dynamic_table();
+  dyn_iterator e = end_dynamic_table();
+  error_code ec;
+  while (i != e) {
+    if (i->getTag() == ELF::DT_NEEDED)
+      break;
+    i.increment(ec);
+    if (ec)
+      report_fatal_error("dynamic table iteration failed");
+  }
+  // Use the same DataRefImpl format as DynRef.
+  return library_iterator(LibraryRef(i->getRawDataRefImpl(), this));
+}
+
+template<support::endianness target_endianness, bool is64Bits>
+error_code ELFObjectFile<target_endianness, is64Bits>
+                        ::getLibraryNext(DataRefImpl Data,
+                                         LibraryRef &Result) const {
+  // Use the same DataRefImpl format as DynRef.
+  dyn_iterator i = dyn_iterator(DynRef(Data, this));
+  dyn_iterator e = end_dynamic_table();
+
+  // Skip the current dynamic table entry.
+  error_code ec;
+  if (i != e) {
+    i.increment(ec);
+    // TODO: proper error handling
+    if (ec)
+      report_fatal_error("dynamic table iteration failed");
+  }
+
+  // Find the next DT_NEEDED entry.
+  while (i != e) {
+    if (i->getTag() == ELF::DT_NEEDED)
+      break;
+    i.increment(ec);
+    if (ec)
+      report_fatal_error("dynamic table iteration failed");
+  }
+  Result = LibraryRef(i->getRawDataRefImpl(), this);
+  return object_error::success;
+}
+
+template<support::endianness target_endianness, bool is64Bits>
+error_code ELFObjectFile<target_endianness, is64Bits>
+         ::getLibraryPath(DataRefImpl Data, StringRef &Res) const {
+  dyn_iterator i = dyn_iterator(DynRef(Data, this));
+  if (i == end_dynamic_table())
+    report_fatal_error("getLibraryPath() called on iterator end");
+
+  if (i->getTag() != ELF::DT_NEEDED)
+    report_fatal_error("Invalid library_iterator");
+
+  // This uses .dynstr to lookup the name of the DT_NEEDED entry.
+  // THis works as long as DT_STRTAB == .dynstr. This is true most of
+  // the time, but the specification allows exceptions.
+  // TODO: This should really use DT_STRTAB instead. Doing this requires
+  // reading the program headers.
+  if (dot_dynstr_sec == NULL)
+    report_fatal_error("Dynamic string table is missing");
+  Res = getString(dot_dynstr_sec, i->getVal());
+  return object_error::success;
+}
+
+template<support::endianness target_endianness, bool is64Bits>
+library_iterator ELFObjectFile<target_endianness, is64Bits>
+                             ::end_libraries_needed() const {
+  dyn_iterator e = end_dynamic_table();
+  // Use the same DataRefImpl format as DynRef.
+  return library_iterator(LibraryRef(e->getRawDataRefImpl(), this));
+}
+
+template<support::endianness target_endianness, bool is64Bits>
 uint8_t ELFObjectFile<target_endianness, is64Bits>::getBytesInAddress() const {
   return is64Bits ? 8 : 4;
 }
@@ -1450,6 +1659,12 @@ ELFObjectFile<target_endianness, is64Bits>::getSymbol(DataRefImpl Symb) const {
 }
 
 template<support::endianness target_endianness, bool is64Bits>
+const typename ELFObjectFile<target_endianness, is64Bits>::Elf_Dyn *
+ELFObjectFile<target_endianness, is64Bits>::getDyn(DataRefImpl DynData) const {
+  return getEntry<Elf_Dyn>(dot_dynamic_sec, DynData.d.a);
+}
+
+template<support::endianness target_endianness, bool is64Bits>
 const typename ELFObjectFile<target_endianness, is64Bits>::Elf_Rel *
 ELFObjectFile<target_endianness, is64Bits>::getRel(DataRefImpl Rel) const {
   return getEntry<Elf_Rel>(Rel.w.b, Rel.w.c);
@@ -1527,6 +1742,54 @@ error_code ELFObjectFile<target_endianness, is64Bits>
   return object_error::success;
 }
 
+template<support::endianness target_endianness, bool is64Bits>
+inline DynRefImpl<target_endianness, is64Bits>
+                 ::DynRefImpl(DataRefImpl DynP, const OwningType *Owner)
+  : DynPimpl(DynP)
+  , OwningObject(Owner) {}
+
+template<support::endianness target_endianness, bool is64Bits>
+inline bool DynRefImpl<target_endianness, is64Bits>
+                      ::operator==(const DynRefImpl &Other) const {
+  return DynPimpl == Other.DynPimpl;
+}
+
+template<support::endianness target_endianness, bool is64Bits>
+inline bool DynRefImpl<target_endianness, is64Bits>
+                      ::operator <(const DynRefImpl &Other) const {
+  return DynPimpl < Other.DynPimpl;
+}
+
+template<support::endianness target_endianness, bool is64Bits>
+inline error_code DynRefImpl<target_endianness, is64Bits>
+                            ::getNext(DynRefImpl &Result) const {
+  return OwningObject->getDynNext(DynPimpl, Result);
+}
+
+template<support::endianness target_endianness, bool is64Bits>
+inline int64_t DynRefImpl<target_endianness, is64Bits>
+                            ::getTag() const {
+  return OwningObject->getDyn(DynPimpl)->d_tag;
+}
+
+template<support::endianness target_endianness, bool is64Bits>
+inline uint64_t DynRefImpl<target_endianness, is64Bits>
+                            ::getVal() const {
+  return OwningObject->getDyn(DynPimpl)->d_un.d_val;
+}
+
+template<support::endianness target_endianness, bool is64Bits>
+inline uint64_t DynRefImpl<target_endianness, is64Bits>
+                            ::getPtr() const {
+  return OwningObject->getDyn(DynPimpl)->d_un.d_ptr;
+}
+
+template<support::endianness target_endianness, bool is64Bits>
+inline DataRefImpl DynRefImpl<target_endianness, is64Bits>
+                             ::getRawDataRefImpl() const {
+  return DynPimpl;
+}
+
 }
 }
 
diff --git a/include/llvm/Object/MachO.h b/include/llvm/Object/MachO.h
index 3edbe08f63..185df06a99 100644
--- a/include/llvm/Object/MachO.h
+++ b/include/llvm/Object/MachO.h
@@ -34,6 +34,8 @@ public:
   virtual symbol_iterator end_symbols() const;
   virtual symbol_iterator begin_dynamic_symbols() const;
   virtual symbol_iterator end_dynamic_symbols() const;
+  virtual library_iterator begin_libraries_needed() const;
+  virtual library_iterator end_libraries_needed() const;
   virtual section_iterator begin_sections() const;
   virtual section_iterator end_sections() const;
 
@@ -92,6 +94,9 @@ protected:
                                            SmallVectorImpl<char> &Result) const;
   virtual error_code getRelocationHidden(DataRefImpl Rel, bool &Result) const;
 
+  virtual error_code getLibraryNext(DataRefImpl LibData, LibraryRef &Res) const;
+  virtual error_code getLibraryPath(DataRefImpl LibData, StringRef &Res) const;
+
 private:
   MachOObject *MachOObj;
   mutable uint32_t RegisteredStringTable;
diff --git a/include/llvm/Object/ObjectFile.h b/include/llvm/Object/ObjectFile.h
index 56d8c249c7..dd47ceb747 100644
--- a/include/llvm/Object/ObjectFile.h
+++ b/include/llvm/Object/ObjectFile.h
@@ -228,6 +228,32 @@ public:
 };
 typedef content_iterator<SymbolRef> symbol_iterator;
 
+/// LibraryRef - This is a value type class that represents a single library in
+/// the list of libraries needed by a shared or dynamic object.
+class LibraryRef {
+  friend class SectionRef;
+  DataRefImpl LibraryPimpl;
+  const ObjectFile *OwningObject;
+
+public:
+  LibraryRef() : OwningObject(NULL) {
+    std::memset(&LibraryPimpl, 0, sizeof(LibraryPimpl));
+  }
+
+  LibraryRef(DataRefImpl LibraryP, const ObjectFile *Owner);
+
+  bool operator==(const LibraryRef &Other) const;
+  bool operator <(const LibraryRef &Other) const;
+
+  error_code getNext(LibraryRef &Result) const;
+
+  // Get the path to this library, as stored in the object file.
+  error_code getPath(StringRef &Result) const;
+
+  DataRefImpl getRawDataRefImpl() const;
+};
+typedef content_iterator<LibraryRef> library_iterator;
+
 const uint64_t UnknownAddressOrSize = ~0ULL;
 
 /// ObjectFile - This class is the base class for all object file types.
@@ -307,6 +333,11 @@ protected:
     return object_error::success;
   }
 
+  // Same for LibraryRef
+  friend class LibraryRef;
+  virtual error_code getLibraryNext(DataRefImpl Lib, LibraryRef &Res) const = 0;
+  virtual error_code getLibraryPath(DataRefImpl Lib, StringRef &Res) const = 0;
+
 public:
 
   virtual symbol_iterator begin_symbols() const = 0;
@@ -318,6 +349,9 @@ public:
   virtual section_iterator begin_sections() const = 0;
   virtual section_iterator end_sections() const = 0;
 
+  virtual library_iterator begin_libraries_needed() const = 0;
+  virtual library_iterator end_libraries_needed() const = 0;
+
   /// @brief The number of bytes used to represent an address in this object
   ///        file format.
   virtual uint8_t getBytesInAddress() const = 0;
@@ -509,6 +543,26 @@ inline error_code RelocationRef::getValueString(SmallVectorImpl<char> &Result)
 inline error_code RelocationRef::getHidden(bool &Result) const {
   return OwningObject->getRelocationHidden(RelocationPimpl, Result);
 }
+// Inline function definitions.
+inline LibraryRef::LibraryRef(DataRefImpl LibraryP, const ObjectFile *Owner)
+  : LibraryPimpl(LibraryP)
+  , OwningObject(Owner) {}
+
+inline bool LibraryRef::operator==(const LibraryRef &Other) const {
+  return LibraryPimpl == Other.LibraryPimpl;
+}
+
+inline bool LibraryRef::operator <(const LibraryRef &Other) const {
+  return LibraryPimpl < Other.LibraryPimpl;
+}
+
+inline error_code LibraryRef::getNext(LibraryRef &Result) const {
+  return OwningObject->getLibraryNext(LibraryPimpl, Result);
+}
+
+inline error_code LibraryRef::getPath(StringRef &Result) const {
+  return OwningObject->getLibraryPath(LibraryPimpl, Result);
+}
 
 } // end namespace object
 } // end namespace llvm