Revert of Gold: Patch linker to implement --long-plt flag.

third_party/binutils/long-plt.patch

-commit ee8713f5cfc38be0e92d78f2afbc77d701ef189d
-Author: Peter Collingbourne <pcc@google.com>
-Date:   Thu Dec 17 16:50:35 2015 -0800
-
-    Implement --long-plt flag (ARM only).
-    
-    gold/
-        PR gold/18780
-        * arm.cc (Target_arm::do_make_data_plt): Choose PLT generator based
-        on value of --long-plt flag.
-        (Output_data_plt_arm_standard::do_get_plt_entry_size): Moved to
-        Output_data_plt_arm_short.
-        (Output_data_plt_arm_standard::do_fill_plt_entry): Likewise.
-        (Output_data_plt_arm_standard::plt_entry): Likewise.
-        (Output_data_plt_arm_standard::do_fill_first_plt_entry): Fix
-        variable reference.
-        (Output_data_plt_arm_short): New class.
-        (Output_data_plt_arm_short::do_fill_plt_entry): Error out on too large
-        PLT offsets instead of asserting.
-        (Output_data_plt_arm_long): New class.
-        * options.h (General_options): Define --long-plt flag.
-
-diff --git a/gold/arm.cc b/gold/arm.cc
-index 6c472bb..a10d785 100644
---- a/gold/arm.cc
-+++ b/gold/arm.cc
-@@ -62,7 +62,10 @@ template<bool big_endian>
- class Output_data_plt_arm;
- 
- template<bool big_endian>
--class Output_data_plt_arm_standard;
-+class Output_data_plt_arm_short;
-+
-+template<bool big_endian>
-+class Output_data_plt_arm_long;
- 
- template<bool big_endian>
- class Stub_table;
-@@ -2532,7 +2535,12 @@ class Target_arm : public Sized_target<32, big_endian>
-   virtual Output_data_plt_arm<big_endian>*
-   do_make_data_plt(Layout* layout, Output_data_space* got_plt)
-   {
--    return new Output_data_plt_arm_standard<big_endian>(layout, got_plt);
-+    if (parameters->options().long_plt())
-+      return new Output_data_plt_arm_long<big_endian>(
-+       layout, got_plt);
-+    else
-+      return new Output_data_plt_arm_short<big_endian>(
-+       layout, got_plt);
-   }
- 
-  private:
-@@ -7382,29 +7390,14 @@ class Output_data_plt_arm_standard : public Output_data_plt_arm<big_endian>
-   do_first_plt_entry_offset() const
-   { return sizeof(first_plt_entry); }
- 
--  // Return the size of a PLT entry.
--  virtual unsigned int
--  do_get_plt_entry_size() const
--  { return sizeof(plt_entry); }
--
-   virtual void
-   do_fill_first_plt_entry(unsigned char* pov,
-                          Arm_address got_address,
-                          Arm_address plt_address);
- 
--  virtual void
--  do_fill_plt_entry(unsigned char* pov,
--                   Arm_address got_address,
--                   Arm_address plt_address,
--                   unsigned int got_offset,
--                   unsigned int plt_offset);
--
-  private:
-   // Template for the first PLT entry.
-   static const uint32_t first_plt_entry[5];
--
--  // Template for subsequent PLT entries.
--  static const uint32_t plt_entry[3];
- };
- 
- // ARM PLTs.
-@@ -7432,7 +7425,7 @@ Output_data_plt_arm_standard<big_endian>::do_fill_first_plt_entry(
- {
-   // Write first PLT entry.  All but the last word are constants.
-   const size_t num_first_plt_words = (sizeof(first_plt_entry)
--                                     / sizeof(plt_entry[0]));
-+                                     / sizeof(first_plt_entry[0]));
-   for (size_t i = 0; i < num_first_plt_words - 1; i++)
-     elfcpp::Swap<32, big_endian>::writeval(pov + i * 4, first_plt_entry[i]);
-   // Last word in first PLT entry is &GOT[0] - .
-@@ -7441,9 +7434,37 @@ Output_data_plt_arm_standard<big_endian>::do_fill_first_plt_entry(
- }
- 
- // Subsequent entries in the PLT.
-+// This class generates short (12-byte) entries, for displacements up to 2^28.
-+
-+template<bool big_endian>
-+class Output_data_plt_arm_short : public Output_data_plt_arm_standard<big_endian>
-+{
-+ public:
-+  Output_data_plt_arm_short(Layout* layout,
-+                           Output_data_space* got_plt)
-+    : Output_data_plt_arm_standard<big_endian>(layout, got_plt)
-+  { }
-+
-+ protected:
-+  // Return the size of a PLT entry.
-+  virtual unsigned int
-+  do_get_plt_entry_size() const
-+  { return sizeof(plt_entry); }
-+
-+  virtual void
-+  do_fill_plt_entry(unsigned char* pov,
-+                   Arm_address got_address,
-+                   Arm_address plt_address,
-+                   unsigned int got_offset,
-+                   unsigned int plt_offset);
-+
-+ private:
-+  // Template for subsequent PLT entries.
-+  static const uint32_t plt_entry[3];
-+};
- 
- template<bool big_endian>
--const uint32_t Output_data_plt_arm_standard<big_endian>::plt_entry[3] =
-+const uint32_t Output_data_plt_arm_short<big_endian>::plt_entry[3] =
- {
-   0xe28fc600,  // add   ip, pc, #0xNN00000
-   0xe28cca00,  // add   ip, ip, #0xNN000
-@@ -7452,7 +7473,7 @@ const uint32_t Output_data_plt_arm_standard<big_endian>::plt_entry[3] =
- 
- template<bool big_endian>
- void
--Output_data_plt_arm_standard<big_endian>::do_fill_plt_entry(
-+Output_data_plt_arm_short<big_endian>::do_fill_plt_entry(
-     unsigned char* pov,
-     Arm_address got_address,
-     Arm_address plt_address,
-@@ -7461,8 +7482,9 @@ Output_data_plt_arm_standard<big_endian>::do_fill_plt_entry(
- {
-   int32_t offset = ((got_address + got_offset)
-                    - (plt_address + plt_offset + 8));
-+  if (offset < 0 || offset > 0x0fffffff)
-+    gold_error(_("PLT offset too large, try linking with --long-plt"));
- 
--  gold_assert(offset >= 0 && offset < 0x0fffffff);
-   uint32_t plt_insn0 = plt_entry[0] | ((offset >> 20) & 0xff);
-   elfcpp::Swap<32, big_endian>::writeval(pov, plt_insn0);
-   uint32_t plt_insn1 = plt_entry[1] | ((offset >> 12) & 0xff);
-@@ -7471,6 +7493,66 @@ Output_data_plt_arm_standard<big_endian>::do_fill_plt_entry(
-   elfcpp::Swap<32, big_endian>::writeval(pov + 8, plt_insn2);
- }
- 
-+// This class generates long (16-byte) entries, for arbitrary displacements.
-+
-+template<bool big_endian>
-+class Output_data_plt_arm_long : public Output_data_plt_arm_standard<big_endian>
-+{
-+ public:
-+  Output_data_plt_arm_long(Layout* layout,
-+                          Output_data_space* got_plt)
-+    : Output_data_plt_arm_standard<big_endian>(layout, got_plt)
-+  { }
-+
-+ protected:
-+  // Return the size of a PLT entry.
-+  virtual unsigned int
-+  do_get_plt_entry_size() const
-+  { return sizeof(plt_entry); }
-+
-+  virtual void
-+  do_fill_plt_entry(unsigned char* pov,
-+                   Arm_address got_address,
-+                   Arm_address plt_address,
-+                   unsigned int got_offset,
-+                   unsigned int plt_offset);
-+
-+ private:
-+  // Template for subsequent PLT entries.
-+  static const uint32_t plt_entry[4];
-+};
-+
-+template<bool big_endian>
-+const uint32_t Output_data_plt_arm_long<big_endian>::plt_entry[4] =
-+{
-+  0xe28fc200,  // add   ip, pc, #0xN0000000
-+  0xe28cc600,  // add   ip, ip, #0xNN00000
-+  0xe28cca00,  // add   ip, ip, #0xNN000
-+  0xe5bcf000,  // ldr   pc, [ip, #0xNNN]!
-+};
-+
-+template<bool big_endian>
-+void
-+Output_data_plt_arm_long<big_endian>::do_fill_plt_entry(
-+    unsigned char* pov,
-+    Arm_address got_address,
-+    Arm_address plt_address,
-+    unsigned int got_offset,
-+    unsigned int plt_offset)
-+{
-+  int32_t offset = ((got_address + got_offset)
-+                   - (plt_address + plt_offset + 8));
-+
-+  uint32_t plt_insn0 = plt_entry[0] | (offset >> 28);
-+  elfcpp::Swap<32, big_endian>::writeval(pov, plt_insn0);
-+  uint32_t plt_insn1 = plt_entry[1] | ((offset >> 20) & 0xff);
-+  elfcpp::Swap<32, big_endian>::writeval(pov + 4, plt_insn1);
-+  uint32_t plt_insn2 = plt_entry[2] | ((offset >> 12) & 0xff);
-+  elfcpp::Swap<32, big_endian>::writeval(pov + 8, plt_insn2);
-+  uint32_t plt_insn3 = plt_entry[3] | (offset & 0xfff);
-+  elfcpp::Swap<32, big_endian>::writeval(pov + 12, plt_insn3);
-+}
-+
- // Write out the PLT.  This uses the hand-coded instructions above,
- // and adjusts them as needed.  This is all specified by the arm ELF
- // Processor Supplement.
-diff --git a/gold/options.h b/gold/options.h
-index cf3b705..5bd93b1e 100644
---- a/gold/options.h
-+++ b/gold/options.h
-@@ -826,6 +826,10 @@ class General_options
-                    "veneer"),
-                 NULL);
- 
-+  DEFINE_bool(long_plt, options::TWO_DASHES, '\0', false,
-+             N_("(ARM only) Generate long PLT entries"),
-+             N_("(ARM only) Do not generate long PLT entries"));
-+
-   DEFINE_bool(g, options::EXACTLY_ONE_DASH, '\0', false,
-              N_("Ignored"), NULL);
-