Fix issue where first reserved word of GOT is not initialized if there

is no PLT.

gold/
	PR gold/16900
	* i386.cc (Output_data_got_plt_i386): New class.
	(Output_data_plt_i386::Output_data_plt_i386): Change type of got_plt
	parameter. Change all callers.
	(Output_data_plt_i386::layout_): Remove.
	(Output_data_plt_i386::got_plt_): Change type.
	(Target_i386::got_plt_): Change type. Change all references.
	(Target_i386::got_section): Create instance of new class.
	(Output_data_got_plt_i386::do_write): New function.
	* x86_64.cc (Output_data_got_plt_x86_64): New class.
	(Output_data_plt_x86_64::Output_data_plt_x86_64): Change type of got_plt
	parameter. Change all callers.
	(Output_data_plt_x86_64::layout_): Remove.
	(Output_data_plt_x86_64::got_plt_): Change type.
	(Target_x86_64::got_plt_): Change type. Change all references.
	(Target_x86_64::got_section): Create instance of new class.
	(Output_data_got_plt_x86_64::do_write): New function.
	(Output_data_plt_x86_64::do_write): Don't write reserved words in GOT.
	(Target_x86_64<size>::init_got_plt_for_update): Create instance of new
	class.

1 files changed, 75 insertions, 35 deletions

diff --git a/gold/x86_64.cc b/gold/x86_64.cc
index aa9e5b4..255ebb9 100644
--- a/gold/x86_64.cc
+++ b/gold/x86_64.cc
@@ -48,6 +48,37 @@ namespace
 
 using namespace gold;
 
+// A class to handle the .got.plt section.
+
+class Output_data_got_plt_x86_64 : public Output_section_data_build
+{
+ public:
+  Output_data_got_plt_x86_64(Layout* layout)
+    : Output_section_data_build(8),
+      layout_(layout)
+  { }
+
+  Output_data_got_plt_x86_64(Layout* layout, off_t data_size)
+    : Output_section_data_build(data_size, 8),
+      layout_(layout)
+  { }
+
+ protected:
+  // Write out the PLT data.
+  void
+  do_write(Output_file*);
+
+  // Write to a map file.
+  void
+  do_print_to_mapfile(Mapfile* mapfile) const
+  { mapfile->print_output_data(this, "** GOT PLT"); }
+
+ private:
+  // A pointer to the Layout class, so that we can find the .dynamic
+  // section when we write out the GOT PLT section.
+  Layout* layout_;
+};
+
 // A class to handle the PLT data.
 // This is an abstract base class that handles most of the linker details
 // but does not know the actual contents of PLT entries.  The derived
@@ -61,9 +92,9 @@ class Output_data_plt_x86_64 : public Output_section_data
 
   Output_data_plt_x86_64(Layout* layout, uint64_t addralign,
 			 Output_data_got<64, false>* got,
-			 Output_data_space* got_plt,
+			 Output_data_got_plt_x86_64* got_plt,
 			 Output_data_space* got_irelative)
-    : Output_section_data(addralign), layout_(layout), tlsdesc_rel_(NULL),
+    : Output_section_data(addralign), tlsdesc_rel_(NULL),
       irelative_rel_(NULL), got_(got), got_plt_(got_plt),
       got_irelative_(got_irelative), count_(0), irelative_count_(0),
       tlsdesc_got_offset_(-1U), free_list_()
@@ -71,12 +102,12 @@ class Output_data_plt_x86_64 : public Output_section_data
 
   Output_data_plt_x86_64(Layout* layout, uint64_t plt_entry_size,
 			 Output_data_got<64, false>* got,
-			 Output_data_space* got_plt,
+			 Output_data_got_plt_x86_64* got_plt,
 			 Output_data_space* got_irelative,
 			 unsigned int plt_count)
     : Output_section_data((plt_count + 1) * plt_entry_size,
 			  plt_entry_size, false),
-      layout_(layout), tlsdesc_rel_(NULL), irelative_rel_(NULL), got_(got),
+      tlsdesc_rel_(NULL), irelative_rel_(NULL), got_(got),
       got_plt_(got_plt), got_irelative_(got_irelative), count_(plt_count),
       irelative_count_(0), tlsdesc_got_offset_(-1U), free_list_()
   {
@@ -268,9 +299,6 @@ class Output_data_plt_x86_64 : public Output_section_data
   void
   do_write(Output_file*);
 
-  // A pointer to the Layout class, so that we can find the .dynamic
-  // section when we write out the GOT PLT section.
-  Layout* layout_;
   // The reloc section.
   Reloc_section* rel_;
   // The TLSDESC relocs, if necessary.  These must follow the regular
@@ -282,7 +310,7 @@ class Output_data_plt_x86_64 : public Output_section_data
   // The .got section.
   Output_data_got<64, false>* got_;
   // The .got.plt section.
-  Output_data_space* got_plt_;
+  Output_data_got_plt_x86_64* got_plt_;
   // The part of the .got.plt section used for IRELATIVE relocs.
   Output_data_space* got_irelative_;
   // The number of PLT entries.
@@ -303,7 +331,7 @@ class Output_data_plt_x86_64_standard : public Output_data_plt_x86_64<size>
  public:
   Output_data_plt_x86_64_standard(Layout* layout,
 				  Output_data_got<64, false>* got,
-				  Output_data_space* got_plt,
+				  Output_data_got_plt_x86_64* got_plt,
 				  Output_data_space* got_irelative)
     : Output_data_plt_x86_64<size>(layout, plt_entry_size,
 				   got, got_plt, got_irelative)
@@ -311,7 +339,7 @@ class Output_data_plt_x86_64_standard : public Output_data_plt_x86_64<size>
 
   Output_data_plt_x86_64_standard(Layout* layout,
 				  Output_data_got<64, false>* got,
-				  Output_data_space* got_plt,
+				  Output_data_got_plt_x86_64* got_plt,
 				  Output_data_space* got_irelative,
 				  unsigned int plt_count)
     : Output_data_plt_x86_64<size>(layout, plt_entry_size,
@@ -618,7 +646,7 @@ class Target_x86_64 : public Sized_target<size, false>
   Output_data_plt_x86_64<size>*
   make_data_plt(Layout* layout,
 		Output_data_got<64, false>* got,
-		Output_data_space* got_plt,
+		Output_data_got_plt_x86_64* got_plt,
 		Output_data_space* got_irelative)
   {
     return this->do_make_data_plt(layout, got, got_plt, got_irelative);
@@ -627,7 +655,7 @@ class Target_x86_64 : public Sized_target<size, false>
   Output_data_plt_x86_64<size>*
   make_data_plt(Layout* layout,
 		Output_data_got<64, false>* got,
-		Output_data_space* got_plt,
+		Output_data_got_plt_x86_64* got_plt,
 		Output_data_space* got_irelative,
 		unsigned int plt_count)
   {
@@ -638,7 +666,7 @@ class Target_x86_64 : public Sized_target<size, false>
   virtual Output_data_plt_x86_64<size>*
   do_make_data_plt(Layout* layout,
 		   Output_data_got<64, false>* got,
-		   Output_data_space* got_plt,
+		   Output_data_got_plt_x86_64* got_plt,
 		   Output_data_space* got_irelative)
   {
     return new Output_data_plt_x86_64_standard<size>(layout, got, got_plt,
@@ -648,7 +676,7 @@ class Target_x86_64 : public Sized_target<size, false>
   virtual Output_data_plt_x86_64<size>*
   do_make_data_plt(Layout* layout,
 		   Output_data_got<64, false>* got,
-		   Output_data_space* got_plt,
+		   Output_data_got_plt_x86_64* got_plt,
 		   Output_data_space* got_irelative,
 		   unsigned int plt_count)
   {
@@ -847,7 +875,7 @@ class Target_x86_64 : public Sized_target<size, false>
   got_section(Symbol_table*, Layout*);
 
   // Get the GOT PLT section.
-  Output_data_space*
+  Output_data_got_plt_x86_64*
   got_plt_section() const
   {
     gold_assert(this->got_plt_ != NULL);
@@ -958,7 +986,7 @@ class Target_x86_64 : public Sized_target<size, false>
   // The PLT section.
   Output_data_plt_x86_64<size>* plt_;
   // The GOT PLT section.
-  Output_data_space* got_plt_;
+  Output_data_got_plt_x86_64* got_plt_;
   // The GOT section for IRELATIVE relocations.
   Output_data_space* got_irelative_;
   // The GOT section for TLSDESC relocations.
@@ -1074,7 +1102,7 @@ Target_x86_64<size>::got_section(Symbol_table* symtab, Layout* layout)
 				       | elfcpp::SHF_WRITE),
 				      this->got_, got_order, true);
 
-      this->got_plt_ = new Output_data_space(8, "** GOT PLT");
+      this->got_plt_ = new Output_data_got_plt_x86_64(layout);
       layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
 				      (elfcpp::SHF_ALLOC
 				       | elfcpp::SHF_WRITE),
@@ -1163,6 +1191,27 @@ Target_x86_64<size>::rela_irelative_section(Layout* layout)
   return this->rela_irelative_;
 }
 
+// Write the first three reserved words of the .got.plt section.
+// The remainder of the section is written while writing the PLT
+// in Output_data_plt_i386::do_write.
+
+void
+Output_data_got_plt_x86_64::do_write(Output_file* of)
+{
+  // The first entry in the GOT is the address of the .dynamic section
+  // aka the PT_DYNAMIC segment.  The next two entries are reserved.
+  // We saved space for them when we created the section in
+  // Target_x86_64::got_section.
+  const off_t got_file_offset = this->offset();
+  gold_assert(this->data_size() >= 24);
+  unsigned char* const got_view = of->get_output_view(got_file_offset, 24);
+  Output_section* dynamic = this->layout_->dynamic_section();
+  uint64_t dynamic_addr = dynamic == NULL ? 0 : dynamic->address();
+  elfcpp::Swap<64, false>::writeval(got_view, dynamic_addr);
+  memset(got_view + 8, 0, 16);
+  of->write_output_view(got_file_offset, 24, got_view);
+}
+
 // Initialize the PLT section.
 
 template<int size>
@@ -1198,7 +1247,7 @@ Output_data_plt_x86_64<size>::add_entry(Symbol_table* symtab, Layout* layout,
   unsigned int* pcount;
   unsigned int offset;
   unsigned int reserved;
-  Output_data_space* got;
+  Output_section_data_build* got;
   if (gsym->type() == elfcpp::STT_GNU_IFUNC
       && gsym->can_use_relative_reloc(false))
     {
@@ -1605,18 +1654,9 @@ Output_data_plt_x86_64<size>::do_write(Output_file* of)
   this->fill_first_plt_entry(pov, got_address, plt_address);
   pov += this->get_plt_entry_size();
 
-  unsigned char* got_pov = got_view;
-
-  // The first entry in the GOT is the address of the .dynamic section
-  // aka the PT_DYNAMIC segment.  The next two entries are reserved.
-  // We saved space for them when we created the section in
-  // Target_x86_64::got_section.
-  Output_section* dynamic = this->layout_->dynamic_section();
-  uint32_t dynamic_addr = dynamic == NULL ? 0 : dynamic->address();
-  elfcpp::Swap<64, false>::writeval(got_pov, dynamic_addr);
-  got_pov += 8;
-  memset(got_pov, 0, 16);
-  got_pov += 16;
+  // The first three entries in the GOT are reserved, and are written
+  // by Output_data_got_plt_x86_64::do_write.
+  unsigned char* got_pov = got_view + 24;
 
   unsigned int plt_offset = this->get_plt_entry_size();
   unsigned int got_offset = 24;
@@ -1777,7 +1817,7 @@ Target_x86_64<size>::init_got_plt_for_update(Symbol_table* symtab,
 				  true);
 
   // Add the three reserved entries.
-  this->got_plt_ = new Output_data_space((plt_count + 3) * 8, 8, "** GOT PLT");
+  this->got_plt_ = new Output_data_got_plt_x86_64(layout, (plt_count + 3) * 8);
   layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
 				  (elfcpp::SHF_ALLOC
 				   | elfcpp::SHF_WRITE),
@@ -4500,7 +4540,7 @@ class Output_data_plt_x86_64_nacl : public Output_data_plt_x86_64<size>
  public:
   Output_data_plt_x86_64_nacl(Layout* layout,
 			      Output_data_got<64, false>* got,
-			      Output_data_space* got_plt,
+			      Output_data_got_plt_x86_64* got_plt,
 			      Output_data_space* got_irelative)
     : Output_data_plt_x86_64<size>(layout, plt_entry_size,
 				   got, got_plt, got_irelative)
@@ -4508,7 +4548,7 @@ class Output_data_plt_x86_64_nacl : public Output_data_plt_x86_64<size>
 
   Output_data_plt_x86_64_nacl(Layout* layout,
 			      Output_data_got<64, false>* got,
-			      Output_data_space* got_plt,
+			      Output_data_got_plt_x86_64* got_plt,
 			      Output_data_space* got_irelative,
 			      unsigned int plt_count)
     : Output_data_plt_x86_64<size>(layout, plt_entry_size,
@@ -4581,7 +4621,7 @@ class Target_x86_64_nacl : public Target_x86_64<size>
   virtual Output_data_plt_x86_64<size>*
   do_make_data_plt(Layout* layout,
 		   Output_data_got<64, false>* got,
-		   Output_data_space* got_plt,
+		   Output_data_got_plt_x86_64* got_plt,
 		   Output_data_space* got_irelative)
   {
     return new Output_data_plt_x86_64_nacl<size>(layout, got, got_plt,
@@ -4591,7 +4631,7 @@ class Target_x86_64_nacl : public Target_x86_64<size>
   virtual Output_data_plt_x86_64<size>*
   do_make_data_plt(Layout* layout,
 		   Output_data_got<64, false>* got,
-		   Output_data_space* got_plt,
+		   Output_data_got_plt_x86_64* got_plt,
 		   Output_data_space* got_irelative,
 		   unsigned int plt_count)
   {