PR 10893

	* i386.cc (class Output_data_plt_i386): Update declarations.
	Define Global_ifunc and Local_ifunc types.  Add global_ifuncs_ and
	local_ifuncs_ fields.
	(Target_i386::do_plt_section_for_global): New function.
	(Target_i386::do_plt_section_for_local): New function.
	(Output_data_plt_i386::Output_data_plt_i386): Add symtab
	parameter; change all callers.  Initialize global_ifuncs_ and
	local_ifuncs_.  If doing a static link define __rel_iplt_start and
	__rel_iplt_end.
	(Output_data_plt_i386::add_entry): Handle IFUNC symbols.
	(Output_data_plt_i386::add_local_ifunc_entry): New function.
	(Output_data_plt_i386::do_write): Fix GOT entries for IFUNC
	symbols.
	(Target_i386::make_plt_section): New function, broken out of
	make_plt_entry.  Set sh_info field of .rel.plt to point to .plt.
	(Target_i386::make_plt_entry): Call make_plt_section.
	(Target_i386::make_local_ifunc_plt_entry): New function.
	(Target_i386::Scan::reloc_needs_iplt_for_ifunc): New function.
	(Target_i386::Scan::local): Handle IFUNC symbols.  Add
	R_386_IRELATIVE to switch.
	(Target_i386::Scan::global): Likewise.
	(Target_i386::Relocate::relocate): Likewise.
	(Target_i386::Relocatable_size_for_reloc): Add R_386_IRELATIVE to
	switch.
	* x86_64.cc (class Output_data_plt_x86_64): Update declarations.
	(Target_x86_64::do_plt_section_for_global): New function.
	(Target_x86_64::do_plt_section_for_local): New function.
	(Output_data_plt_x86_64::Output_data_plt_x86_64): Add symtab
	parameter; change all callers.  If doing a static link define
	__rela_iplt_start and __rela_iplt_end.
	(Output_data_plt_x86_64::add_entry): Handle IFUNC symbols.
	(Output_data_plt_x86_64::add_local_ifunc_entry): New function.
	(Target_x86_64::make_plt_section): Set sh_info field of .rel.plt
	to point to .plt.
	(Target_x86_64::make_local_ifunc_plt_entry): New function.
	(Target_x86_64::Scan::check_non_pic): Add R_X86_64_IRELATIVE to
	switch.
	(Target_x86_64::Scan::reloc_needs_iplt_for_ifunc): New function.
	(Target_x86_64::Scan::local): Handle IFUNC symbols.  Add
	R_X86_64_IRELATIVE to switch.
	(Target_x86_64::Scan::global): Likewise.
	(Target_x86_64::Relocate::relocate): Likewise.
	(Target_x86_64::Relocatable_size_for_reloc): Add R_X86_64_IRELATIVE to
	switch.
	* target.h (class Target): Add plt_section_for_global and
	plt_section_for_local functions.  Add do_plt_section_for_global
	and do_plt_section_for_local virtual functions.
	* symtab.h (Symbol::needs_plt_entry): Handle IFUNC symbol.  Add
	clarifying comments.
	(Symbol::use_plt_offset): Handle IFUNC symbol.
	* object.cc (Sized_relobj::Sized_relobj): Initialize
	local_plt_offsets_.
	(Sized_relobj::local_has_plt_offset): New function.
	(Sized_relobj::local_plt_offset): New function.
	(Sized_relobj::set_local_plt_offset): New function.
	(Sized_relobj::do_count): Handle IFUNC symbol.
	* object.h (class Symbol_value): Add is_ifunc_symbol_ field.  Take
	a bit away from input_shndx_ field.  Add set_is_func_symbol and
	is_ifunc_symbol functions.
	(class Sized_relobj): Update declarations.  Remove Tls_got_entry
	and Local_tls_got_offsets.  Define Local_plt_offsets.  Add
	local_plt_offsets_ field.
	(Sized_relobj::clear_local_symbols): Clear local_plt_offsets_.
	* output.h (class Output_section_data): Add non-const
	output_section function.
	(class Output_data_got): Update declarations.
	(class Output_data_got::Got_entry): Add use_plt_offset_ field.
	Add use_plt_offset parameter to global and local constructors.
	Change all callers.  Change local_sym_index_ field to 31 bits.
	Change GSYM_CODE and CONSTANT_CODE accordingly.
	* output.cc (Output_data_reloc_base::do_adjust_output_section): If
	doing a static link don't set sh_link field.
	(Output_data_got::Got_entry::write): Use PLT offset if
	appropriate.
	(Output_data_got::add_global_plt): New function.
	(Output_data_got::add_local_plt): New function.
	* target-reloc.h (relocate_section): Handle IFUNC symbol.
	* defstd.cc (in_section): Remove entries for __rel_iplt_start,
	__rel_iplt_end, __rela_iplt_start, and __rela_iplt_end.
	* configure.ac: Set IFUNC automake conditional for glibc >= 2.11.
	* testsuite/Makefile.am: Add a bunch of IFUNC tests, all within
	IFUNC conditional.
	* testsuite/ifunc-sel.h: New file.
	* testsuite/ifuncmain1.c: New file.
	* testsuite/ifuncmain1vis.c: New file.
	* testsuite/ifuncmod1.c: New file.
	* testsuite/ifuncdep2.c: New file.
	* testsuite/ifuncmain2.c: New file.
	* testsuite/ifuncmain3.c: New file.
	* testsuite/ifuncmod3.c: New file.
	* testsuite/ifuncmain4.c: New file.
	* testsuite/ifuncmain5.c: New file.
	* testsuite/ifuncmod5.c: New file.
	* testsuite/ifuncmain6pie.c: New file.
	* testsuite/ifuncmod6.c: New file.
	* testsuite/ifuncmain7.c: New file.
	* configure, testsuite/Makefile.in: Rebuild.

1 files changed, 439 insertions, 116 deletions

diff --git a/gold/i386.cc b/gold/i386.cc
index b272967..56d405b 100644
--- a/gold/i386.cc
+++ b/gold/i386.cc
@@ -45,7 +45,113 @@ namespace
 
 using namespace gold;
 
-class Output_data_plt_i386;
+// A class to handle the PLT data.
+
+class Output_data_plt_i386 : public Output_section_data
+{
+ public:
+  typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
+
+  Output_data_plt_i386(Symbol_table*, Layout*, Output_data_space*);
+
+  // Add an entry to the PLT.
+  void
+  add_entry(Symbol* gsym);
+
+  // Add an entry to the PLT for a local STT_GNU_IFUNC symbol.
+  unsigned int
+  add_local_ifunc_entry(Sized_relobj<32, false>* relobj,
+			unsigned int local_sym_index);
+
+  // Return the .rel.plt section data.
+  Reloc_section*
+  rel_plt() const
+  { return this->rel_; }
+
+  // Return where the TLS_DESC relocations should go.
+  Reloc_section*
+  rel_tls_desc(Layout*);
+
+  // Return the number of PLT entries.
+  unsigned int
+  entry_count() const
+  { return this->count_; }
+
+  // Return the offset of the first non-reserved PLT entry.
+  static unsigned int
+  first_plt_entry_offset()
+  { return plt_entry_size; }
+
+  // Return the size of a PLT entry.
+  static unsigned int
+  get_plt_entry_size()
+  { return plt_entry_size; }
+
+ protected:
+  void
+  do_adjust_output_section(Output_section* os);
+
+  // Write to a map file.
+  void
+  do_print_to_mapfile(Mapfile* mapfile) const
+  { mapfile->print_output_data(this, _("** PLT")); }
+
+ private:
+  // The size of an entry in the PLT.
+  static const int plt_entry_size = 16;
+
+  // The first entry in the PLT for an executable.
+  static unsigned char exec_first_plt_entry[plt_entry_size];
+
+  // The first entry in the PLT for a shared object.
+  static unsigned char dyn_first_plt_entry[plt_entry_size];
+
+  // Other entries in the PLT for an executable.
+  static unsigned char exec_plt_entry[plt_entry_size];
+
+  // Other entries in the PLT for a shared object.
+  static unsigned char dyn_plt_entry[plt_entry_size];
+
+  // Set the final size.
+  void
+  set_final_data_size()
+  { this->set_data_size((this->count_ + 1) * plt_entry_size); }
+
+  // Write out the PLT data.
+  void
+  do_write(Output_file*);
+
+  // We keep a list of global STT_GNU_IFUNC symbols, each with its
+  // offset in the GOT.
+  struct Global_ifunc
+  {
+    Symbol* sym;
+    unsigned int got_offset;
+  };
+
+  // We keep a list of local STT_GNU_IFUNC symbols, each with its
+  // offset in the GOT.
+  struct Local_ifunc
+  {
+    Sized_relobj<32, false>* object;
+    unsigned int local_sym_index;
+    unsigned int got_offset;
+  };
+
+  // The reloc section.
+  Reloc_section* rel_;
+  // The TLS_DESC relocations, if necessary.  These must follow the
+  // regular PLT relocs.
+  Reloc_section* tls_desc_rel_;
+  // The .got.plt section.
+  Output_data_space* got_plt_;
+  // The number of PLT entries.
+  unsigned int count_;
+  // Global STT_GNU_IFUNC symbols.
+  std::vector<Global_ifunc> global_ifuncs_;
+  // Local STT_GNU_IFUNC symbols.
+  std::vector<Local_ifunc> local_ifuncs_;
+};
 
 // The i386 target class.
 // TLS info comes from
@@ -172,6 +278,15 @@ class Target_i386 : public Target_freebsd<32, false>
     return Target::do_is_local_label_name(name);
   }
 
+  // Return the PLT section.
+  Output_data*
+  do_plt_section_for_global(const Symbol*) const
+  { return this->plt_section(); }
+
+  Output_data*
+  do_plt_section_for_local(const Relobj*, unsigned int) const
+  { return this->plt_section(); }
+
   // Return whether SYM is call to a non-split function.
   bool
   do_is_call_to_non_split(const Symbol* sym, unsigned int) const;
@@ -255,6 +370,9 @@ class Target_i386 : public Target_freebsd<32, false>
     inline bool
     possible_function_pointer_reloc(unsigned int r_type);
 
+    bool
+    reloc_needs_plt_for_ifunc(Sized_relobj<32, false>*, unsigned int r_type);
+
     static void
     unsupported_reloc_local(Sized_relobj<32, false>*, unsigned int r_type);
 
@@ -415,10 +533,20 @@ class Target_i386 : public Target_freebsd<32, false>
     return this->got_tlsdesc_;
   }
 
+  // Create the PLT section.
+  void
+  make_plt_section(Symbol_table* symtab, Layout* layout);
+
   // Create a PLT entry for a global symbol.
   void
   make_plt_entry(Symbol_table*, Layout*, Symbol*);
 
+  // Create a PLT entry for a local STT_GNU_IFUNC symbol.
+  void
+  make_local_ifunc_plt_entry(Symbol_table*, Layout*,
+			     Sized_relobj<32, false>* relobj,
+			     unsigned int local_sym_index);
+
   // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
   void
   define_tls_base_symbol(Symbol_table*, Layout*);
@@ -586,100 +714,38 @@ Target_i386::rel_dyn_section(Layout* layout)
   return this->rel_dyn_;
 }
 
-// A class to handle the PLT data.
-
-class Output_data_plt_i386 : public Output_section_data
-{
- public:
-  typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
-
-  Output_data_plt_i386(Layout*, Output_data_space*);
-
-  // Add an entry to the PLT.
-  void
-  add_entry(Symbol* gsym);
-
-  // Return the .rel.plt section data.
-  const Reloc_section*
-  rel_plt() const
-  { return this->rel_; }
-
-  // Return where the TLS_DESC relocations should go.
-  Reloc_section*
-  rel_tls_desc(Layout*);
-
-  // Return the number of PLT entries.
-  unsigned int
-  entry_count() const
-  { return this->count_; }
-
-  // Return the offset of the first non-reserved PLT entry.
-  static unsigned int
-  first_plt_entry_offset()
-  { return plt_entry_size; }
-
-  // Return the size of a PLT entry.
-  static unsigned int
-  get_plt_entry_size()
-  { return plt_entry_size; }
-
- protected:
-  void
-  do_adjust_output_section(Output_section* os);
-
-  // Write to a map file.
-  void
-  do_print_to_mapfile(Mapfile* mapfile) const
-  { mapfile->print_output_data(this, _("** PLT")); }
-
- private:
-  // The size of an entry in the PLT.
-  static const int plt_entry_size = 16;
-
-  // The first entry in the PLT for an executable.
-  static unsigned char exec_first_plt_entry[plt_entry_size];
-
-  // The first entry in the PLT for a shared object.
-  static unsigned char dyn_first_plt_entry[plt_entry_size];
-
-  // Other entries in the PLT for an executable.
-  static unsigned char exec_plt_entry[plt_entry_size];
-
-  // Other entries in the PLT for a shared object.
-  static unsigned char dyn_plt_entry[plt_entry_size];
-
-  // Set the final size.
-  void
-  set_final_data_size()
-  { this->set_data_size((this->count_ + 1) * plt_entry_size); }
-
-  // Write out the PLT data.
-  void
-  do_write(Output_file*);
-
-  // The reloc section.
-  Reloc_section* rel_;
-  // The TLS_DESC relocations, if necessary.  These must follow the
-  // regular PLT relocs.
-  Reloc_section* tls_desc_rel_;
-  // The .got.plt section.
-  Output_data_space* got_plt_;
-  // The number of PLT entries.
-  unsigned int count_;
-};
-
 // Create the PLT section.  The ordinary .got section is an argument,
 // since we need to refer to the start.  We also create our own .got
 // section just for PLT entries.
 
-Output_data_plt_i386::Output_data_plt_i386(Layout* layout,
+Output_data_plt_i386::Output_data_plt_i386(Symbol_table* symtab,
+					   Layout* layout,
 					   Output_data_space* got_plt)
-  : Output_section_data(4), tls_desc_rel_(NULL), got_plt_(got_plt), count_(0)
+  : Output_section_data(4), tls_desc_rel_(NULL), got_plt_(got_plt), count_(0),
+    global_ifuncs_(), local_ifuncs_()
 {
   this->rel_ = new Reloc_section(false);
   layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
 				  elfcpp::SHF_ALLOC, this->rel_,
 				  ORDER_DYNAMIC_PLT_RELOCS, false);
+
+  if (parameters->doing_static_link())
+    {
+      // A statically linked executable will only have a .rel.plt
+      // section to hold R_386_IRELATIVE relocs for STT_GNU_IFUNC
+      // symbols.  The library will use these symbols to locate the
+      // IRELATIVE relocs at program startup time.
+      symtab->define_in_output_data("__rel_iplt_start", NULL,
+				    Symbol_table::PREDEFINED,
+				    this->rel_, 0, 0, elfcpp::STT_NOTYPE,
+				    elfcpp::STB_GLOBAL, elfcpp::STV_HIDDEN,
+				    0, false, true);
+      symtab->define_in_output_data("__rel_iplt_end", NULL,
+				    Symbol_table::PREDEFINED,
+				    this->rel_, 0, 0, elfcpp::STT_NOTYPE,
+				    elfcpp::STB_GLOBAL, elfcpp::STV_HIDDEN,
+				    0, true, true);
+    }
 }
 
 void
@@ -711,15 +777,58 @@ Output_data_plt_i386::add_entry(Symbol* gsym)
   this->got_plt_->set_current_data_size(got_offset + 4);
 
   // Every PLT entry needs a reloc.
-  gsym->set_needs_dynsym_entry();
-  this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
-			 got_offset);
+  if (gsym->type() == elfcpp::STT_GNU_IFUNC
+      && gsym->can_use_relative_reloc(false))
+    {
+      this->rel_->add_symbolless_global_addend(gsym, elfcpp::R_386_IRELATIVE,
+					       this->got_plt_, got_offset);
+      struct Global_ifunc gi;
+      gi.sym = gsym;
+      gi.got_offset = got_offset;
+      this->global_ifuncs_.push_back(gi);
+    }
+  else
+    {
+      gsym->set_needs_dynsym_entry();
+      this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
+			     got_offset);
+    }
 
   // Note that we don't need to save the symbol.  The contents of the
   // PLT are independent of which symbols are used.  The symbols only
   // appear in the relocations.
 }
 
+// Add an entry to the PLT for a local STT_GNU_IFUNC symbol.  Return
+// the PLT offset.
+
+unsigned int
+Output_data_plt_i386::add_local_ifunc_entry(Sized_relobj<32, false>* relobj,
+					    unsigned int local_sym_index)
+{
+  unsigned int plt_offset = (this->count_ + 1) * plt_entry_size;
+  ++this->count_;
+
+  section_offset_type got_offset = this->got_plt_->current_data_size();
+
+  // Every PLT entry needs a GOT entry which points back to the PLT
+  // entry.
+  this->got_plt_->set_current_data_size(got_offset + 4);
+
+  // Every PLT entry needs a reloc.
+  this->rel_->add_symbolless_local_addend(relobj, local_sym_index,
+					  elfcpp::R_386_IRELATIVE,
+					  this->got_plt_, got_offset);
+
+  struct Local_ifunc li;
+  li.object = relobj;
+  li.local_sym_index = local_sym_index;
+  li.got_offset = got_offset;
+  this->local_ifuncs_.push_back(li);
+
+  return plt_offset;
+}
+
 // Return where the TLS_DESC relocations should go, creating it if
 // necessary. These follow the JUMP_SLOT relocations.
 
@@ -858,6 +967,32 @@ Output_data_plt_i386::do_write(Output_file* of)
       elfcpp::Swap<32, false>::writeval(got_pov, plt_address + plt_offset + 6);
     }
 
+  // If any STT_GNU_IFUNC symbols have PLT entries, we need to change
+  // the GOT to point to the actual symbol value, rather than point to
+  // the PLT entry.  That will let the dynamic linker call the right
+  // function when resolving IRELATIVE relocations.
+  for (std::vector<Global_ifunc>::const_iterator p =
+	 this->global_ifuncs_.begin();
+       p != this->global_ifuncs_.end();
+       ++p)
+    {
+      const Sized_symbol<32>* ssym =
+	static_cast<const Sized_symbol<32>*>(p->sym);
+      elfcpp::Swap<32, false>::writeval(got_view + p->got_offset,
+					ssym->value());
+    }
+
+  for (std::vector<Local_ifunc>::const_iterator p =
+	 this->local_ifuncs_.begin();
+       p != this->local_ifuncs_.end();
+       ++p)
+    {
+      const Symbol_value<32>* psymval =
+	p->object->local_symbol(p->local_sym_index);
+      elfcpp::Swap<32, false>::writeval(got_view + p->got_offset,
+					psymval->value(p->object, 0));
+    }
+
   gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
   gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
 
@@ -865,29 +1000,56 @@ Output_data_plt_i386::do_write(Output_file* of)
   of->write_output_view(got_file_offset, got_size, got_view);
 }
 
-// Create a PLT entry for a global symbol.
+// Create the PLT section.
 
 void
-Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym)
+Target_i386::make_plt_section(Symbol_table* symtab, Layout* layout)
 {
-  if (gsym->has_plt_offset())
-    return;
-
   if (this->plt_ == NULL)
     {
       // Create the GOT sections first.
       this->got_section(symtab, layout);
 
-      this->plt_ = new Output_data_plt_i386(layout, this->got_plt_);
+      this->plt_ = new Output_data_plt_i386(symtab, layout, this->got_plt_);
       layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
 				      (elfcpp::SHF_ALLOC
 				       | elfcpp::SHF_EXECINSTR),
 				      this->plt_, ORDER_PLT, false);
+
+      // Make the sh_info field of .rel.plt point to .plt.
+      Output_section* rel_plt_os = this->plt_->rel_plt()->output_section();
+      rel_plt_os->set_info_section(this->plt_->output_section());
     }
+}
+
+// Create a PLT entry for a global symbol.
 
+void
+Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym)
+{
+  if (gsym->has_plt_offset())
+    return;
+  if (this->plt_ == NULL)
+    this->make_plt_section(symtab, layout);
   this->plt_->add_entry(gsym);
 }
 
+// Make a PLT entry for a local STT_GNU_IFUNC symbol.
+
+void
+Target_i386::make_local_ifunc_plt_entry(Symbol_table* symtab, Layout* layout,
+					Sized_relobj<32, false>* relobj,
+					unsigned int local_sym_index)
+{
+  if (relobj->local_has_plt_offset(local_sym_index))
+    return;
+  if (this->plt_ == NULL)
+    this->make_plt_section(symtab, layout);
+  unsigned int plt_offset = this->plt_->add_local_ifunc_entry(relobj,
+							      local_sym_index);
+  relobj->set_local_plt_offset(local_sym_index, plt_offset);
+}
+
 // Return the number of entries in the PLT.
 
 unsigned int
@@ -1035,6 +1197,75 @@ Target_i386::Scan::unsupported_reloc_local(Sized_relobj<32, false>* object,
 	     object->name().c_str(), r_type);
 }
 
+// Return whether we need to make a PLT entry for a relocation of a
+// given type against a STT_GNU_IFUNC symbol.
+
+bool
+Target_i386::Scan::reloc_needs_plt_for_ifunc(Sized_relobj<32, false>* object,
+					     unsigned int r_type)
+{
+  switch (r_type)
+    {
+    case elfcpp::R_386_NONE:
+    case elfcpp::R_386_GNU_VTINHERIT:
+    case elfcpp::R_386_GNU_VTENTRY:
+      return false;
+
+    case elfcpp::R_386_32:
+    case elfcpp::R_386_16:
+    case elfcpp::R_386_8:
+    case elfcpp::R_386_PC32:
+    case elfcpp::R_386_PC16:
+    case elfcpp::R_386_PC8:
+    case elfcpp::R_386_PLT32:
+    case elfcpp::R_386_GOTOFF:
+    case elfcpp::R_386_GOTPC:
+    case elfcpp::R_386_GOT32:
+      return true;
+
+    case elfcpp::R_386_COPY:
+    case elfcpp::R_386_GLOB_DAT:
+    case elfcpp::R_386_JUMP_SLOT:
+    case elfcpp::R_386_RELATIVE:
+    case elfcpp::R_386_IRELATIVE:
+    case elfcpp::R_386_TLS_TPOFF:
+    case elfcpp::R_386_TLS_DTPMOD32:
+    case elfcpp::R_386_TLS_DTPOFF32:
+    case elfcpp::R_386_TLS_TPOFF32:
+    case elfcpp::R_386_TLS_DESC:
+      // We will give an error later.
+      return false;
+
+    case elfcpp::R_386_TLS_GD:
+    case elfcpp::R_386_TLS_GOTDESC:
+    case elfcpp::R_386_TLS_DESC_CALL:
+    case elfcpp::R_386_TLS_LDM:
+    case elfcpp::R_386_TLS_LDO_32:
+    case elfcpp::R_386_TLS_IE:
+    case elfcpp::R_386_TLS_IE_32:
+    case elfcpp::R_386_TLS_GOTIE:
+    case elfcpp::R_386_TLS_LE:
+    case elfcpp::R_386_TLS_LE_32:
+      gold_error(_("%s: unsupported TLS reloc %u for IFUNC symbol"),
+		 object->name().c_str(), r_type);
+      return false;
+
+    case elfcpp::R_386_32PLT:
+    case elfcpp::R_386_TLS_GD_32:
+    case elfcpp::R_386_TLS_GD_PUSH:
+    case elfcpp::R_386_TLS_GD_CALL:
+    case elfcpp::R_386_TLS_GD_POP:
+    case elfcpp::R_386_TLS_LDM_32:
+    case elfcpp::R_386_TLS_LDM_PUSH:
+    case elfcpp::R_386_TLS_LDM_CALL:
+    case elfcpp::R_386_TLS_LDM_POP:
+    case elfcpp::R_386_USED_BY_INTEL_200:
+    default:
+      // We will give an error later.
+      return false;
+    }
+}
+
 // Scan a relocation for a local symbol.
 
 inline void
@@ -1048,6 +1279,14 @@ Target_i386::Scan::local(Symbol_table* symtab,
 			 unsigned int r_type,
 			 const elfcpp::Sym<32, false>& lsym)
 {
+  // A local STT_GNU_IFUNC symbol may require a PLT entry.
+  if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC
+      && this->reloc_needs_plt_for_ifunc(object, r_type))
+    {
+      unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
+      target->make_local_ifunc_plt_entry(symtab, layout, object, r_sym);
+    }
+
   switch (r_type)
     {
     case elfcpp::R_386_NONE:
@@ -1066,9 +1305,9 @@ Target_i386::Scan::local(Symbol_table* symtab,
         {
           Reloc_section* rel_dyn = target->rel_dyn_section(layout);
           unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
-          rel_dyn->add_local_relative(object, r_sym, elfcpp::R_386_RELATIVE,
-                                      output_section, data_shndx,
-                                      reloc.get_r_offset());
+	  rel_dyn->add_local_relative(object, r_sym, elfcpp::R_386_RELATIVE,
+				      output_section, data_shndx,
+				      reloc.get_r_offset());
         }
       break;
 
@@ -1125,17 +1364,27 @@ Target_i386::Scan::local(Symbol_table* symtab,
         // The symbol requires a GOT entry.
         Output_data_got<32, false>* got = target->got_section(symtab, layout);
         unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
-        if (got->add_local(object, r_sym, GOT_TYPE_STANDARD))
+
+	// For a STT_GNU_IFUNC symbol we want the PLT offset.  That
+	// lets function pointers compare correctly with shared
+	// libraries.  Otherwise we would need an IRELATIVE reloc.
+	bool is_new;
+	if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC)
+	  is_new = got->add_local_plt(object, r_sym, GOT_TYPE_STANDARD);
+	else
+	  is_new = got->add_local(object, r_sym, GOT_TYPE_STANDARD);
+        if (is_new)
           {
             // If we are generating a shared object, we need to add a
             // dynamic RELATIVE relocation for this symbol's GOT entry.
             if (parameters->options().output_is_position_independent())
               {
                 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
-                unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
-                rel_dyn->add_local_relative(
-                    object, r_sym, elfcpp::R_386_RELATIVE, got,
-                    object->local_got_offset(r_sym, GOT_TYPE_STANDARD));
+		unsigned int got_offset =
+		  object->local_got_offset(r_sym, GOT_TYPE_STANDARD);
+		rel_dyn->add_local_relative(object, r_sym,
+					    elfcpp::R_386_RELATIVE,
+					    got, got_offset);
               }
           }
       }
@@ -1147,6 +1396,7 @@ Target_i386::Scan::local(Symbol_table* symtab,
     case elfcpp::R_386_GLOB_DAT:
     case elfcpp::R_386_JUMP_SLOT:
     case elfcpp::R_386_RELATIVE:
+    case elfcpp::R_386_IRELATIVE:
     case elfcpp::R_386_TLS_TPOFF:
     case elfcpp::R_386_TLS_DTPMOD32:
     case elfcpp::R_386_TLS_DTPOFF32:
@@ -1394,6 +1644,11 @@ Target_i386::Scan::global(Symbol_table* symtab,
 			  unsigned int r_type,
 			  Symbol* gsym)
 {
+  // A STT_GNU_IFUNC symbol may require a PLT entry.
+  if (gsym->type() == elfcpp::STT_GNU_IFUNC
+      && this->reloc_needs_plt_for_ifunc(object, r_type))
+    target->make_plt_entry(symtab, layout, gsym);
+
   switch (r_type)
     {
     case elfcpp::R_386_NONE:
@@ -1424,13 +1679,31 @@ Target_i386::Scan::global(Symbol_table* symtab,
 	        target->copy_reloc(symtab, layout, object,
 	                           data_shndx, output_section, gsym, reloc);
               }
+	    else if (r_type == elfcpp::R_386_32
+		     && gsym->type() == elfcpp::STT_GNU_IFUNC
+		     && gsym->can_use_relative_reloc(false)
+		     && !gsym->is_from_dynobj()
+		     && !gsym->is_undefined()
+		     && !gsym->is_preemptible())
+	      {
+		// Use an IRELATIVE reloc for a locally defined
+		// STT_GNU_IFUNC symbol.  This makes a function
+		// address in a PIE executable match the address in a
+		// shared library that it links against.
+		Reloc_section* rel_dyn = target->rel_dyn_section(layout);
+		rel_dyn->add_symbolless_global_addend(gsym,
+						      elfcpp::R_386_IRELATIVE,
+						      output_section,
+						      object, data_shndx,
+						      reloc.get_r_offset());
+	      }
             else if (r_type == elfcpp::R_386_32
                      && gsym->can_use_relative_reloc(false))
               {
                 Reloc_section* rel_dyn = target->rel_dyn_section(layout);
-                rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
-                                             output_section, object,
-                                             data_shndx, reloc.get_r_offset());
+		rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
+					     output_section, object,
+					     data_shndx, reloc.get_r_offset());
               }
             else
               {
@@ -1485,7 +1758,13 @@ Target_i386::Scan::global(Symbol_table* symtab,
         // The symbol requires a GOT entry.
         Output_data_got<32, false>* got = target->got_section(symtab, layout);
         if (gsym->final_value_is_known())
-          got->add_global(gsym, GOT_TYPE_STANDARD);
+	  {
+	    // For a STT_GNU_IFUNC symbol we want the PLT address.
+	    if (gsym->type() == elfcpp::STT_GNU_IFUNC)
+	      got->add_global_plt(gsym, GOT_TYPE_STANDARD);
+	    else
+	      got->add_global(gsym, GOT_TYPE_STANDARD);
+	  }
         else
           {
             // If this symbol is not fully resolved, we need to add a
@@ -1493,15 +1772,34 @@ Target_i386::Scan::global(Symbol_table* symtab,
             Reloc_section* rel_dyn = target->rel_dyn_section(layout);
             if (gsym->is_from_dynobj()
                 || gsym->is_undefined()
-                || gsym->is_preemptible())
+                || gsym->is_preemptible()
+		|| (gsym->type() == elfcpp::STT_GNU_IFUNC
+		    && parameters->options().output_is_position_independent()))
               got->add_global_with_rel(gsym, GOT_TYPE_STANDARD,
                                        rel_dyn, elfcpp::R_386_GLOB_DAT);
             else
               {
-                if (got->add_global(gsym, GOT_TYPE_STANDARD))
-                  rel_dyn->add_global_relative(
-                      gsym, elfcpp::R_386_RELATIVE, got,
-                      gsym->got_offset(GOT_TYPE_STANDARD));
+		// For a STT_GNU_IFUNC symbol we want to write the PLT
+		// offset into the GOT, so that function pointer
+		// comparisons work correctly.
+		bool is_new;
+		if (gsym->type() != elfcpp::STT_GNU_IFUNC)
+		  is_new = got->add_global(gsym, GOT_TYPE_STANDARD);
+		else
+		  {
+		    is_new = got->add_global_plt(gsym, GOT_TYPE_STANDARD);
+		    // Tell the dynamic linker to use the PLT address
+		    // when resolving relocations.
+		    if (gsym->is_from_dynobj()
+			&& !parameters->options().shared())
+		      gsym->set_needs_dynsym_value();
+		  }
+                if (is_new)
+		  {
+		    unsigned int got_off = gsym->got_offset(GOT_TYPE_STANDARD);
+		    rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
+						 got, got_off);
+		  }
               }
           }
       }
@@ -1534,6 +1832,7 @@ Target_i386::Scan::global(Symbol_table* symtab,
     case elfcpp::R_386_GLOB_DAT:
     case elfcpp::R_386_JUMP_SLOT:
     case elfcpp::R_386_RELATIVE:
+    case elfcpp::R_386_IRELATIVE:
     case elfcpp::R_386_TLS_TPOFF:
     case elfcpp::R_386_TLS_DTPMOD32:
     case elfcpp::R_386_TLS_DTPOFF32:
@@ -1866,19 +2165,41 @@ Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
 	}
     }
 
+  const Sized_relobj<32, false>* object = relinfo->object;
+
   // Pick the value to use for symbols defined in shared objects.
   Symbol_value<32> symval;
   if (gsym != NULL
-      && gsym->use_plt_offset(r_type == elfcpp::R_386_PC8
-			      || r_type == elfcpp::R_386_PC16
-			      || r_type == elfcpp::R_386_PC32))
+      && gsym->type() == elfcpp::STT_GNU_IFUNC
+      && r_type == elfcpp::R_386_32
+      && gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF)
+      && gsym->can_use_relative_reloc(false)
+      && !gsym->is_from_dynobj()
+      && !gsym->is_undefined()
+      && !gsym->is_preemptible())
+    {
+      // In this case we are generating a R_386_IRELATIVE reloc.  We
+      // want to use the real value of the symbol, not the PLT offset.
+    }
+  else if (gsym != NULL
+	   && gsym->use_plt_offset(r_type == elfcpp::R_386_PC8
+				   || r_type == elfcpp::R_386_PC16
+				   || r_type == elfcpp::R_386_PC32))
     {
       symval.set_output_value(target->plt_section()->address()
 			      + gsym->plt_offset());
       psymval = &symval;
     }
-
-  const Sized_relobj<32, false>* object = relinfo->object;
+  else if (gsym == NULL && psymval->is_ifunc_symbol())
+    {
+      unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
+      if (object->local_has_plt_offset(r_sym))
+	{
+	  symval.set_output_value(target->plt_section()->address()
+				  + object->local_plt_offset(r_sym));
+	  psymval = &symval;
+	}
+    }
 
   // Get the GOT offset if needed.
   // The GOT pointer points to the end of the GOT section.
@@ -2001,6 +2322,7 @@ Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
     case elfcpp::R_386_GLOB_DAT:
     case elfcpp::R_386_JUMP_SLOT:
     case elfcpp::R_386_RELATIVE:
+    case elfcpp::R_386_IRELATIVE:
       // These are outstanding tls relocs, which are unexpected when
       // linking.
     case elfcpp::R_386_TLS_TPOFF:
@@ -2713,6 +3035,7 @@ Target_i386::Relocatable_size_for_reloc::get_size_for_reloc(
     case elfcpp::R_386_GLOB_DAT:
     case elfcpp::R_386_JUMP_SLOT:
     case elfcpp::R_386_RELATIVE:
+    case elfcpp::R_386_IRELATIVE:
     case elfcpp::R_386_TLS_TPOFF:
     case elfcpp::R_386_TLS_DTPMOD32:
     case elfcpp::R_386_TLS_DTPOFF32: