vendor/binutils/binutils-master-20070703-075419vendor/binutils

1 files changed, 409 insertions, 0 deletions

diff --git a/gold/reloc.h b/gold/reloc.h
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+// reloc.h -- relocate input files for gold   -*- C++ -*-
+
+#ifndef GOLD_RELOC_H
+#define GOLD_RELOC_H
+
+#include <byteswap.h>
+
+#include "workqueue.h"
+
+namespace gold
+{
+
+class General_options;
+class Relobj;
+class Read_relocs_data;
+class Symbol;
+class Layout;
+
+template<int size>
+class Sized_symbol;
+
+template<int size, bool big_endian>
+class Sized_relobj;
+
+template<int size>
+class Symbol_value;
+
+template<int sh_type, bool dynamic, int size, bool big_endian>
+class Output_data_reloc;
+
+// A class to read the relocations for an object file, and then queue
+// up a task to see if they require any GOT/PLT/COPY relocations in
+// the symbol table.
+
+class Read_relocs : public Task
+{
+ public:
+  // SYMTAB_LOCK is used to lock the symbol table.  BLOCKER should be
+  // unblocked when the Scan_relocs task completes.
+  Read_relocs(const General_options& options, Symbol_table* symtab,
+	      Layout* layout, Relobj* object, Task_token* symtab_lock,
+	      Task_token* blocker)
+    : options_(options), symtab_(symtab), layout_(layout), object_(object),
+      symtab_lock_(symtab_lock), blocker_(blocker)
+  { }
+
+  // The standard Task methods.
+
+  Is_runnable_type
+  is_runnable(Workqueue*);
+
+  Task_locker*
+  locks(Workqueue*);
+
+  void
+  run(Workqueue*);
+
+ private:
+  const General_options& options_;
+  Symbol_table* symtab_;
+  Layout* layout_;
+  Relobj* object_;
+  Task_token* symtab_lock_;
+  Task_token* blocker_;
+};
+
+// Scan the relocations for an object to see if they require any
+// GOT/PLT/COPY relocations.
+
+class Scan_relocs : public Task
+{
+ public:
+  // SYMTAB_LOCK is used to lock the symbol table.  BLOCKER should be
+  // unblocked when the task completes.
+  Scan_relocs(const General_options& options, Symbol_table* symtab,
+	      Layout* layout, Relobj* object, Read_relocs_data* rd,
+	      Task_token* symtab_lock, Task_token* blocker)
+    : options_(options), symtab_(symtab), layout_(layout), object_(object),
+      rd_(rd), symtab_lock_(symtab_lock), blocker_(blocker)
+  { }
+
+  // The standard Task methods.
+
+  Is_runnable_type
+  is_runnable(Workqueue*);
+
+  Task_locker*
+  locks(Workqueue*);
+
+  void
+  run(Workqueue*);
+
+ private:
+  class Scan_relocs_locker;
+
+  const General_options& options_;
+  Symbol_table* symtab_;
+  Layout* layout_;
+  Relobj* object_;
+  Read_relocs_data* rd_;
+  Task_token* symtab_lock_;
+  Task_token* blocker_;
+};
+
+// A class to perform all the relocations for an object file.
+
+class Relocate_task : public Task
+{
+ public:
+  Relocate_task(const General_options& options, const Symbol_table* symtab,
+		const Layout* layout, Relobj* object, Output_file* of,
+		Task_token* final_blocker)
+    : options_(options), symtab_(symtab), layout_(layout), object_(object),
+      of_(of), final_blocker_(final_blocker)
+  { }
+
+  // The standard Task methods.
+
+  Is_runnable_type
+  is_runnable(Workqueue*);
+
+  Task_locker*
+  locks(Workqueue*);
+
+  void
+  run(Workqueue*);
+
+ private:
+  class Relocate_locker;
+
+  const General_options& options_;
+  const Symbol_table* symtab_;
+  const Layout* layout_;
+  Relobj* object_;
+  Output_file* of_;
+  Task_token* final_blocker_;
+};
+
+// Standard relocation routines which are used on many targets.  Here
+// SIZE and BIG_ENDIAN refer to the target, not the relocation type.
+
+template<int size, bool big_endian>
+class Relocate_functions
+{
+private:
+  // Do a simple relocation with the addend in the section contents.
+  // VALSIZE is the size of the value.
+  template<int valsize>
+  static inline void
+  rel(unsigned char* view,
+      typename elfcpp::Swap<valsize, big_endian>::Valtype value)
+  {
+    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
+    Valtype* wv = reinterpret_cast<Valtype*>(view);
+    Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv);
+    elfcpp::Swap<valsize, big_endian>::writeval(wv, x + value);
+  }
+
+  // Do a simple relocation using a Symbol_value with the addend in
+  // the section contents.  VALSIZE is the size of the value to
+  // relocate.
+  template<int valsize>
+  static inline void
+  rel(unsigned char* view,
+      const Sized_relobj<size, big_endian>* object,
+      const Symbol_value<size>* psymval)
+  {
+    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
+    Valtype* wv = reinterpret_cast<Valtype*>(view);
+    Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv);
+    x = psymval->value(object, x);
+    elfcpp::Swap<valsize, big_endian>::writeval(wv, x);
+  }
+
+  // Do a simple PC relative relocation with the addend in the section
+  // contents.  VALSIZE is the size of the value.
+  template<int valsize>
+  static inline void
+  pcrel(unsigned char* view,
+	typename elfcpp::Swap<valsize, big_endian>::Valtype value,
+	typename elfcpp::Elf_types<size>::Elf_Addr address)
+  {
+    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
+    Valtype* wv = reinterpret_cast<Valtype*>(view);
+    Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv);
+    elfcpp::Swap<valsize, big_endian>::writeval(wv, x + value - address);
+  }
+
+  // Do a simple PC relative relocation with a Symbol_value with the
+  // addend in the section contents.  VALSIZE is the size of the
+  // value.
+  template<int valsize>
+  static inline void
+  pcrel(unsigned char* view,
+	const Sized_relobj<size, big_endian>* object,
+	const Symbol_value<size>* psymval,
+	typename elfcpp::Elf_types<size>::Elf_Addr address)
+  {
+    typedef typename elfcpp::Swap<valsize, big_endian>::Valtype Valtype;
+    Valtype* wv = reinterpret_cast<Valtype*>(view);
+    Valtype x = elfcpp::Swap<valsize, big_endian>::readval(wv);
+    x = psymval->value(object, x);
+    elfcpp::Swap<valsize, big_endian>::writeval(wv, x - address);
+  }
+
+  typedef Relocate_functions<size, big_endian> This;
+
+public:
+  // Do a simple 8-bit REL relocation with the addend in the section
+  // contents.
+  static inline void
+  rel8(unsigned char* view, unsigned char value)
+  { This::template rel<8>(view, value); }
+
+  static inline void
+  rel8(unsigned char* view,
+       const Sized_relobj<size, big_endian>* object,
+       const Symbol_value<size>* psymval)
+  { This::template rel<8>(view, object, psymval); }
+
+  // Do a simple 8-bit PC relative relocation with the addend in the
+  // section contents.
+  static inline void
+  pcrel8(unsigned char* view, unsigned char value,
+	 typename elfcpp::Elf_types<size>::Elf_Addr address)
+  { This::template pcrel<8>(view, value, address); }
+
+  static inline void
+  pcrel8(unsigned char* view,
+	 const Sized_relobj<size, big_endian>* object,
+	 const Symbol_value<size>* psymval,
+	 typename elfcpp::Elf_types<size>::Elf_Addr address)
+  { This::template pcrel<8>(view, object, psymval, address); }
+
+  // Do a simple 16-bit REL relocation with the addend in the section
+  // contents.
+  static inline void
+  rel16(unsigned char* view, elfcpp::Elf_Half value)
+  { This::template rel<16>(view, value); }
+
+  static inline void
+  rel16(unsigned char* view,
+	const Sized_relobj<size, big_endian>* object,
+	const Symbol_value<size>* psymval)
+  { This::template rel<16>(view, object, psymval); }
+
+  // Do a simple 32-bit PC relative REL relocation with the addend in
+  // the section contents.
+  static inline void
+  pcrel16(unsigned char* view, elfcpp::Elf_Word value,
+	  typename elfcpp::Elf_types<size>::Elf_Addr address)
+  { This::template pcrel<16>(view, value, address); }
+
+  static inline void
+  pcrel16(unsigned char* view,
+	  const Sized_relobj<size, big_endian>* object,
+	  const Symbol_value<size>* psymval,
+	  typename elfcpp::Elf_types<size>::Elf_Addr address)
+  { This::template pcrel<16>(view, object, psymval, address); }
+
+  // Do a simple 32-bit REL relocation with the addend in the section
+  // contents.
+  static inline void
+  rel32(unsigned char* view, elfcpp::Elf_Word value)
+  { This::template rel<32>(view, value); }
+
+  static inline void
+  rel32(unsigned char* view,
+	const Sized_relobj<size, big_endian>* object,
+	const Symbol_value<size>* psymval)
+  { This::template rel<32>(view, object, psymval); }
+
+  // Do a simple 32-bit PC relative REL relocation with the addend in
+  // the section contents.
+  static inline void
+  pcrel32(unsigned char* view, elfcpp::Elf_Word value,
+	  typename elfcpp::Elf_types<size>::Elf_Addr address)
+  { This::template pcrel<32>(view, value, address); }
+
+  static inline void
+  pcrel32(unsigned char* view,
+	  const Sized_relobj<size, big_endian>* object,
+	  const Symbol_value<size>* psymval,
+	  typename elfcpp::Elf_types<size>::Elf_Addr address)
+  { This::template pcrel<32>(view, object, psymval, address); }
+
+  // Do a simple 64-bit REL relocation with the addend in the section
+  // contents.
+  static inline void
+  rel64(unsigned char* view, elfcpp::Elf_Xword value)
+  { This::template rel<64>(view, value); }
+
+  static inline void
+  rel64(unsigned char* view,
+	const Sized_relobj<size, big_endian>* object,
+	const Symbol_value<size>* psymval)
+  { This::template rel<64>(view, object, psymval); }
+
+  // Do a simple 64-bit PC relative REL relocation with the addend in
+  // the section contents.
+  static inline void
+  pcrel64(unsigned char* view, elfcpp::Elf_Xword value,
+	  typename elfcpp::Elf_types<size>::Elf_Addr address)
+  { This::template pcrel<64>(view, value, address); }
+
+  static inline void
+  pcrel64(unsigned char* view,
+	  const Sized_relobj<size, big_endian>* object,
+	  const Symbol_value<size>* psymval,
+	  typename elfcpp::Elf_types<size>::Elf_Addr address)
+  { This::template pcrel<64>(view, object, psymval, address); }
+};
+
+// We try to avoid COPY relocations when possible.  A COPY relocation
+// may be required when an executable refers to a variable defined in
+// a shared library.  COPY relocations are problematic because they
+// tie the executable to the exact size of the variable in the shared
+// library.  We can avoid them if all the references to the variable
+// are in a writeable section.  In that case we can simply use dynamic
+// relocations.  However, when scanning relocs, we don't know when we
+// see the relocation whether we will be forced to use a COPY
+// relocation or not.  So we have to save the relocation during the
+// reloc scanning, and then emit it as a dynamic relocation if
+// necessary.  This class implements that.  It is used by the target
+// specific code.
+
+template<int size, bool big_endian>
+class Copy_relocs
+{
+ public:
+  Copy_relocs()
+    : entries_()
+  { }
+
+  // Return whether we need a COPY reloc for a reloc against GSYM,
+  // which is being applied to section SHNDX in OBJECT.
+  static bool
+  need_copy_reloc(const General_options*, Relobj* object, unsigned int shndx,
+		  Sized_symbol<size>* gsym);
+
+  // Save a Rel against SYM for possible emission later.  SHNDX is the
+  // index of the section to which the reloc is being applied.
+  void
+  save(Symbol* sym, Relobj*, unsigned int shndx,
+       const elfcpp::Rel<size, big_endian>&);
+
+  // Save a Rela against SYM for possible emission later.
+  void
+  save(Symbol* sym, Relobj*, unsigned int shndx,
+       const elfcpp::Rela<size, big_endian>&);
+
+  // Return whether there are any relocs to emit.  This also discards
+  // entries which need not be emitted.
+  bool
+  any_to_emit();
+
+  // Emit relocs for each symbol which did not get a COPY reloc (i.e.,
+  // is still defined in the dynamic object).
+  template<int sh_type>
+  void
+  emit(Output_data_reloc<sh_type, true, size, big_endian>*);
+
+ private:
+  typedef typename elfcpp::Elf_types<size>::Elf_Addr Address;
+  typedef typename elfcpp::Elf_types<size>::Elf_Addr Addend;
+
+  // This POD class holds the entries we are saving.
+  class Copy_reloc_entry
+  {
+   public:
+    Copy_reloc_entry(Symbol* sym, unsigned int reloc_type,
+		     Relobj* relobj, unsigned int shndx,
+		     Address address, Addend addend)
+      : sym_(sym), reloc_type_(reloc_type), relobj_(relobj),
+	shndx_(shndx), address_(address), addend_(addend)
+    { }
+
+    // Return whether we should emit this reloc.  If we should not
+    // emit, we clear it.
+    bool
+    should_emit();
+
+    // Emit this reloc.
+
+    void
+    emit(Output_data_reloc<elfcpp::SHT_REL, true, size, big_endian>*);
+
+    void
+    emit(Output_data_reloc<elfcpp::SHT_RELA, true, size, big_endian>*);
+
+   private:
+    Symbol* sym_;
+    unsigned int reloc_type_;
+    Relobj* relobj_;
+    unsigned int shndx_;
+    Address address_;
+    Addend addend_;
+  };
+
+  // A list of relocs to be saved.
+  typedef std::vector<Copy_reloc_entry> Copy_reloc_entries;
+
+  // The list of relocs we are saving.
+  Copy_reloc_entries entries_;
+};
+
+} // End namespace gold.
+
+#endif // !defined(GOLD_RELOC_H)