2009-10-21 Doug Kwan <dougkwan@google.com>

	* arm.cc: Update copyright comments.
	(Target_arm): New forward class template declaration.
	(Arm_address): New type.
	(ARM_MAX_FWD_BRANCH_OFFSET, ARM_MAX_BWD_BRANCH_OFFSET,
	THM_MAX_FWD_BRANCH_OFFSET, THM_MAX_BWD_BRANCH_OFFSET,
	THM2_MAX_FWD_BRANCH_OFFSET, THM2_MAX_BWD_BRANCH_OFFSET): New
	constants.
	(Insn_template): Same.
	(DEF_STUBS): New macro.
	(Stub_type): New enum type.
	(Stub_template): New class definition.
	(Stub): Same.
	(Reloc_stub): Same.
	(Stub_factory): Same.
	(Target_arm::Target_arm): Initialize may_use_blx_ and
	should_force_pic_veneer_.
	(Target_arm::may_use_blx, Target_arm::set_may_use_blx,
	Target_arm::should_force_pic_veneer,
	Target_arm::set_should_force_pic_veneer, Target_arm::using_thumb2,
	Target_arm::using_thumb_only, Target_arm:;default_target): New
	method defintions.
	(Target_arm::may_use_blx_, Target_arm::should_force_pic_veneer_):
	New data member declarations.
	(Insn_template::size, Insn_template::alignment): New method defintions.
	(Stub_template::Stub_template): New method definition.
	(Reloc_stub::Key::name, Reloc_stub::stub_type_for_reloc,
	Reloc_stub::do_fixed_endian_write, Reloc_stub::do_write): Same.
	(Stub_factory::Stub_factory): New method definition.
	* gold.h (string_hash): New template.
	* output.h (Input_section_specifier::hash_value): Use
	gold::string_hash.
	(Input_section_specifier::string_hash): Remove.
	* stringpool.cc (Stringpool_template::string_hash): Use
	gold::string_hash.

1 files changed, 37 insertions, 0 deletions

diff --git a/gold/gold.h b/gold/gold.h
index 3f514cdd1d..dc5a1c1b35 100644
--- a/gold/gold.h
+++ b/gold/gold.h
@@ -349,6 +349,43 @@ is_prefix_of(const char* prefix, const char* str)
   return strncmp(prefix, str, strlen(prefix)) == 0;
 }
 
+// We sometimes need to hash strings.  Ideally we should use std::tr1::hash or
+// __gnu_cxx::hash on some systems but there is no guarantee that either
+// one is available.  For portability, we define simple string hash functions.
+
+template<typename Char_type>
+inline size_t
+string_hash(const Char_type* s, size_t length)
+{
+  // This is the hash function used by the dynamic linker for
+  // DT_GNU_HASH entries.  I compared this to a Fowler/Noll/Vo hash
+  // for a C++ program with 385,775 global symbols.  This hash
+  // function was very slightly worse.  However, it is much faster to
+  // compute.  Overall wall clock time was a win.
+  const unsigned char* p = reinterpret_cast<const unsigned char*>(s);
+  size_t h = 5381;
+  for (size_t i = 0; i < length * sizeof(Char_type); ++i)
+    h = h * 33 + *p++;
+  return h;
+}
+
+// Same as above except we expect the string to be zero terminated.
+
+template<typename Char_type>
+inline size_t
+string_hash(const Char_type* s)
+{
+  const unsigned char* p = reinterpret_cast<const unsigned char*>(s);
+  size_t h = 5381;
+  for (size_t i = 0; s[i] != 0; ++i)
+    {
+      for (size_t j = 0; j < sizeof(Char_type); j++)
+	h = h * 33 + *p++;
+    }
+
+  return h;
+}
+
 } // End namespace gold.
 
 #endif // !defined(GOLD_GOLD_H)