Automatic date update in version.in
[platform/upstream/binutils.git] / gold / plugin.cc
index 345df28..0339d42 100644 (file)
@@ -1,6 +1,6 @@
 // plugin.cc -- plugin manager for gold      -*- C++ -*-
 
-// Copyright 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
+// Copyright (C) 2008-2014 Free Software Foundation, Inc.
 // Written by Cary Coutant <ccoutant@google.com>.
 
 // This file is part of gold.
 #include <vector>
 
 #ifdef ENABLE_PLUGINS
+#ifdef HAVE_DLFCN_H
 #include <dlfcn.h>
+#elif defined (HAVE_WINDOWS_H)
+#include <windows.h>
+#else
+#error Unknown how to handle dynamic-load-libraries.
 #endif
 
+#if !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H)
+
+#define RTLD_NOW 0      /* Dummy value.  */
+static void *
+dlopen(const char *file, int mode ATTRIBUTE_UNUSED)
+{
+  return LoadLibrary(file);
+}
+
+static void *
+dlsym(void *handle, const char *name)
+{
+  return reinterpret_cast<void *>(
+     GetProcAddress(static_cast<HMODULE>(handle),name));
+}
+
+static const char *
+dlerror(void)
+{
+  return "unable to load dll";
+}
+
+#endif /* !defined (HAVE_DLFCN_H) && defined (HAVE_WINDOWS_H)  */
+#endif /* ENABLE_PLUGINS */
+
 #include "parameters.h"
 #include "errors.h"
 #include "fileread.h"
@@ -41,6 +71,7 @@
 #include "target.h"
 #include "readsyms.h"
 #include "symtab.h"
+#include "descriptors.h"
 #include "elfcpp.h"
 
 namespace gold
@@ -78,6 +109,9 @@ static enum ld_plugin_status
 get_symbols(const void *handle, int nsyms, struct ld_plugin_symbol *syms);
 
 static enum ld_plugin_status
+get_symbols_v2(const void *handle, int nsyms, struct ld_plugin_symbol *syms);
+
+static enum ld_plugin_status
 add_input_file(const char *pathname);
 
 static enum ld_plugin_status
@@ -89,6 +123,38 @@ set_extra_library_path(const char *path);
 static enum ld_plugin_status
 message(int level, const char *format, ...);
 
+static enum ld_plugin_status
+get_input_section_count(const void* handle, unsigned int* count);
+
+static enum ld_plugin_status
+get_input_section_type(const struct ld_plugin_section section,
+                       unsigned int* type);
+
+static enum ld_plugin_status
+get_input_section_name(const struct ld_plugin_section section,
+                       char** section_name_ptr);
+
+static enum ld_plugin_status
+get_input_section_contents(const struct ld_plugin_section section,
+                           const unsigned char** section_contents,
+                          size_t* len);
+
+static enum ld_plugin_status
+update_section_order(const struct ld_plugin_section *section_list,
+                    unsigned int num_sections);
+
+static enum ld_plugin_status
+allow_section_ordering();
+
+static enum ld_plugin_status
+allow_unique_segment_for_sections();
+
+static enum ld_plugin_status
+unique_segment_for_sections(const char* segment_name,
+                           uint64_t flags,
+                           uint64_t align,
+                           const struct ld_plugin_section *section_list,
+                           unsigned int num_sections);
 };
 
 #endif // ENABLE_PLUGINS
@@ -133,7 +199,8 @@ Plugin::load()
   sscanf(ver, "%d.%d", &major, &minor);
 
   // Allocate and populate a transfer vector.
-  const int tv_fixed_size = 17;
+  const int tv_fixed_size = 26;
+
   int tv_size = this->args_.size() + tv_fixed_size;
   ld_plugin_tv* tv = new ld_plugin_tv[tv_size];
 
@@ -157,6 +224,8 @@ Plugin::load()
     tv[i].tv_u.tv_val = LDPO_REL;
   else if (parameters->options().shared())
     tv[i].tv_u.tv_val = LDPO_DYN;
+  else if (parameters->options().pie())
+    tv[i].tv_u.tv_val = LDPO_PIE;
   else
     tv[i].tv_u.tv_val = LDPO_EXEC;
 
@@ -204,6 +273,10 @@ Plugin::load()
   tv[i].tv_u.tv_get_symbols = get_symbols;
 
   ++i;
+  tv[i].tv_tag = LDPT_GET_SYMBOLS_V2;
+  tv[i].tv_u.tv_get_symbols = get_symbols_v2;
+
+  ++i;
   tv[i].tv_tag = LDPT_ADD_INPUT_FILE;
   tv[i].tv_u.tv_add_input_file = add_input_file;
 
@@ -216,6 +289,39 @@ Plugin::load()
   tv[i].tv_u.tv_set_extra_library_path = set_extra_library_path;
 
   ++i;
+  tv[i].tv_tag = LDPT_GET_INPUT_SECTION_COUNT;
+  tv[i].tv_u.tv_get_input_section_count = get_input_section_count;
+
+  ++i;
+  tv[i].tv_tag = LDPT_GET_INPUT_SECTION_TYPE;
+  tv[i].tv_u.tv_get_input_section_type = get_input_section_type;
+
+  ++i;
+  tv[i].tv_tag = LDPT_GET_INPUT_SECTION_NAME;
+  tv[i].tv_u.tv_get_input_section_name = get_input_section_name;
+
+  ++i;
+  tv[i].tv_tag = LDPT_GET_INPUT_SECTION_CONTENTS;
+  tv[i].tv_u.tv_get_input_section_contents = get_input_section_contents;
+
+  ++i;
+  tv[i].tv_tag = LDPT_UPDATE_SECTION_ORDER;
+  tv[i].tv_u.tv_update_section_order = update_section_order;
+
+  ++i;
+  tv[i].tv_tag = LDPT_ALLOW_SECTION_ORDERING;
+  tv[i].tv_u.tv_allow_section_ordering = allow_section_ordering;
+
+  ++i;
+  tv[i].tv_tag = LDPT_ALLOW_UNIQUE_SEGMENT_FOR_SECTIONS;
+  tv[i].tv_u.tv_allow_unique_segment_for_sections
+    = allow_unique_segment_for_sections;
+
+  ++i;
+  tv[i].tv_tag = LDPT_UNIQUE_SEGMENT_FOR_SECTIONS;
+  tv[i].tv_u.tv_unique_segment_for_sections = unique_segment_for_sections;
+
+  ++i;
   tv[i].tv_tag = LDPT_NULL;
   tv[i].tv_u.tv_val = 0;
 
@@ -326,8 +432,9 @@ Plugin_manager::~Plugin_manager()
 // Load all plugin libraries.
 
 void
-Plugin_manager::load_plugins()
+Plugin_manager::load_plugins(Layout* layout)
 {
+  this->layout_ = layout;
   for (this->current_ = this->plugins_.begin();
        this->current_ != this->plugins_.end();
        ++this->current_)
@@ -338,7 +445,7 @@ Plugin_manager::load_plugins()
 
 Pluginobj*
 Plugin_manager::claim_file(Input_file* input_file, off_t offset,
-                           off_t filesize)
+                           off_t filesize, Object* elf_object)
 {
   if (this->in_replacement_phase_)
     return NULL;
@@ -350,6 +457,9 @@ Plugin_manager::claim_file(Input_file* input_file, off_t offset,
   this->plugin_input_file_.offset = offset;
   this->plugin_input_file_.filesize = filesize;
   this->plugin_input_file_.handle = reinterpret_cast<void*>(handle);
+  if (elf_object != NULL)
+    this->objects_.push_back(elf_object);
+  this->in_claim_file_handler_ = true;
 
   for (this->current_ = this->plugins_.begin();
        this->current_ != this->plugins_.end();
@@ -358,9 +468,11 @@ Plugin_manager::claim_file(Input_file* input_file, off_t offset,
       if ((*this->current_)->claim_file(&this->plugin_input_file_))
         {
          this->any_claimed_ = true;
+         this->in_claim_file_handler_ = false;
 
-          if (this->objects_.size() > handle)
-            return this->objects_[handle];
+          if (this->objects_.size() > handle
+              && this->objects_[handle]->pluginobj() != NULL)
+            return this->objects_[handle]->pluginobj();
 
           // If the plugin claimed the file but did not call the
           // add_symbols callback, we need to create the Pluginobj now.
@@ -369,6 +481,7 @@ Plugin_manager::claim_file(Input_file* input_file, off_t offset,
         }
     }
 
+  this->in_claim_file_handler_ = false;
   return NULL;
 }
 
@@ -402,7 +515,7 @@ Plugin_manager::save_input_group(Input_group* input_group)
 void
 Plugin_manager::all_symbols_read(Workqueue* workqueue, Task* task,
                                  Input_objects* input_objects,
-                                Symbol_table* symtab, Layout* layout,
+                                Symbol_table* symtab,
                                 Dirsearch* dirpath, Mapfile* mapfile,
                                 Task_token** last_blocker)
 {
@@ -411,7 +524,6 @@ Plugin_manager::all_symbols_read(Workqueue* workqueue, Task* task,
   this->task_ = task;
   this->input_objects_ = input_objects;
   this->symtab_ = symtab;
-  this->layout_ = layout;
   this->dirpath_ = dirpath;
   this->mapfile_ = mapfile;
   this->this_blocker_ = NULL;
@@ -586,6 +698,14 @@ Plugin_manager::layout_deferred_objects()
 void
 Plugin_manager::cleanup()
 {
+  if (this->any_added_)
+    {
+      // If any input files were added, close all the input files.
+      // This is because the plugin may want to remove them, and on
+      // Windows you are not allowed to remove an open file.
+      close_all_descriptors();
+    }
+
   for (this->current_ = this->plugins_.begin();
        this->current_ != this->plugins_.end();
        ++this->current_)
@@ -599,12 +719,20 @@ Pluginobj*
 Plugin_manager::make_plugin_object(unsigned int handle)
 {
   // Make sure we aren't asked to make an object for the same handle twice.
-  if (this->objects_.size() != handle)
+  if (this->objects_.size() != handle
+      && this->objects_[handle]->pluginobj() != NULL)
     return NULL;
 
   Pluginobj* obj = make_sized_plugin_object(this->input_file_,
                                             this->plugin_input_file_.offset,
                                             this->plugin_input_file_.filesize);
+
+
+  // If the elf object for this file was pushed into the objects_ vector, delete
+  // it to make room for the Pluginobj as this file is claimed.
+  if (this->objects_.size() != handle)
+    this->objects_.pop_back();
+
   this->objects_.push_back(obj);
   return obj;
 }
@@ -616,7 +744,7 @@ ld_plugin_status
 Plugin_manager::get_input_file(unsigned int handle,
                                struct ld_plugin_input_file* file)
 {
-  Pluginobj* obj = this->object(handle);
+  Pluginobj* obj = this->object(handle)->pluginobj();
   if (obj == NULL)
     return LDPS_BAD_HANDLE;
 
@@ -634,7 +762,11 @@ Plugin_manager::get_input_file(unsigned int handle,
 ld_plugin_status
 Plugin_manager::release_input_file(unsigned int handle)
 {
-  Pluginobj* obj = this->object(handle);
+  if (this->object(handle) == NULL)
+    return LDPS_BAD_HANDLE;
+
+  Pluginobj* obj = this->object(handle)->pluginobj();
+
   if (obj == NULL)
     return LDPS_BAD_HANDLE;
 
@@ -642,13 +774,30 @@ Plugin_manager::release_input_file(unsigned int handle)
   return LDPS_OK;
 }
 
+// Get the elf object corresponding to the handle. Return NULL if we
+// found a Pluginobj instead.
+
+Object*
+Plugin_manager::get_elf_object(const void* handle)
+{
+  Object* obj = this->object(
+      static_cast<unsigned int>(reinterpret_cast<intptr_t>(handle)));
+
+  // The object should not be a Pluginobj.
+  if (obj == NULL
+      || obj->pluginobj() != NULL)
+    return NULL;
+
+  return obj;
+}
+
 ld_plugin_status
 Plugin_manager::get_view(unsigned int handle, const void **viewp)
 {
   off_t offset;
   size_t filesize;
   Input_file *input_file;
-  if (this->objects_.size() == handle)
+  if (this->in_claim_file_handler_)
     {
       // We are being called from the claim_file hook.
       const struct ld_plugin_input_file &f = this->plugin_input_file_;
@@ -659,7 +808,9 @@ Plugin_manager::get_view(unsigned int handle, const void **viewp)
   else
     {
       // An already claimed file.
-      Pluginobj* obj = this->object(handle);
+      if (this->object(handle) == NULL)
+        return LDPS_BAD_HANDLE;
+      Pluginobj* obj = this->object(handle)->pluginobj();
       if (obj == NULL)
         return LDPS_BAD_HANDLE;
       offset = obj->offset();
@@ -725,11 +876,13 @@ Pluginobj::Pluginobj(const std::string& name, Input_file* input_file,
 {
 }
 
-// Return TRUE if a defined symbol might be reachable from outside the
-// universe of claimed objects.
+// Return TRUE if a defined symbol is referenced from outside the
+// universe of claimed objects.  Only references from relocatable,
+// non-IR (unclaimed) objects count as a reference.  References from
+// dynamic objects count only as "visible".
 
 static inline bool
-is_visible_from_outside(Symbol* lsym)
+is_referenced_from_outside(Symbol* lsym)
 {
   if (lsym->in_real_elf())
     return true;
@@ -737,6 +890,17 @@ is_visible_from_outside(Symbol* lsym)
     return true;
   if (parameters->options().is_undefined(lsym->name()))
     return true;
+  return false;
+}
+
+// Return TRUE if a defined symbol might be reachable from outside the
+// load module.
+
+static inline bool
+is_visible_from_outside(Symbol* lsym)
+{
+  if (lsym->in_dyn())
+    return true;
   if (parameters->options().export_dynamic() || parameters->options().shared())
     return lsym->is_externally_visible();
   return false;
@@ -745,8 +909,18 @@ is_visible_from_outside(Symbol* lsym)
 // Get symbol resolution info.
 
 ld_plugin_status
-Pluginobj::get_symbol_resolution_info(int nsyms, ld_plugin_symbol* syms) const
-{
+Pluginobj::get_symbol_resolution_info(int nsyms,
+                                     ld_plugin_symbol* syms,
+                                     int version) const
+{
+  // For version 1 of this interface, we cannot use
+  // LDPR_PREVAILING_DEF_IRONLY_EXP, so we return LDPR_PREVAILING_DEF
+  // instead.
+  const ld_plugin_symbol_resolution ldpr_prevailing_def_ironly_exp
+      = (version > 1
+        ? LDPR_PREVAILING_DEF_IRONLY_EXP
+        : LDPR_PREVAILING_DEF);
+
   if (nsyms > this->nsyms_)
     return LDPS_NO_SYMS;
 
@@ -777,9 +951,14 @@ Pluginobj::get_symbol_resolution_info(int nsyms, ld_plugin_symbol* syms) const
           if (lsym->source() != Symbol::FROM_OBJECT)
             res = LDPR_RESOLVED_EXEC;
           else if (lsym->object()->pluginobj() == this)
-            res = (is_visible_from_outside(lsym)
-                   ? LDPR_PREVAILING_DEF
-                   : LDPR_PREVAILING_DEF_IRONLY);
+           {
+             if (is_referenced_from_outside(lsym))
+               res = LDPR_PREVAILING_DEF;
+             else if (is_visible_from_outside(lsym))
+               res = ldpr_prevailing_def_ironly_exp;
+             else
+               res = LDPR_PREVAILING_DEF_IRONLY;
+           }
           else if (lsym->object()->pluginobj() != NULL)
             res = LDPR_RESOLVED_IR;
           else if (lsym->object()->is_dynamic())
@@ -793,9 +972,14 @@ Pluginobj::get_symbol_resolution_info(int nsyms, ld_plugin_symbol* syms) const
           if (lsym->source() != Symbol::FROM_OBJECT)
             res = LDPR_PREEMPTED_REG;
           else if (lsym->object() == static_cast<const Object*>(this))
-            res = (is_visible_from_outside(lsym)
-                   ? LDPR_PREVAILING_DEF
-                   : LDPR_PREVAILING_DEF_IRONLY);
+           {
+             if (is_referenced_from_outside(lsym))
+               res = LDPR_PREVAILING_DEF;
+             else if (is_visible_from_outside(lsym))
+               res = ldpr_prevailing_def_ironly_exp;
+             else
+               res = LDPR_PREVAILING_DEF_IRONLY;
+           }
           else
             res = (lsym->object()->pluginobj() != NULL
                    ? LDPR_PREEMPTED_IR
@@ -869,8 +1053,6 @@ Sized_pluginobj<size, big_endian>::do_add_symbols(Symbol_table* symtab,
   elfcpp::Sym<size, big_endian> sym(symbuf);
   elfcpp::Sym_write<size, big_endian> osym(symbuf);
 
-  typedef typename elfcpp::Elf_types<size>::Elf_WXword Elf_size_type;
-
   this->symbols_.resize(this->nsyms_);
 
   for (int i = 0; i < this->nsyms_; ++i)
@@ -941,7 +1123,7 @@ Sized_pluginobj<size, big_endian>::do_add_symbols(Symbol_table* symtab,
 
       osym.put_st_name(0);
       osym.put_st_value(0);
-      osym.put_st_size(static_cast<Elf_size_type>(isym->size));
+      osym.put_st_size(0);
       osym.put_st_info(bind, elfcpp::STT_NOTYPE);
       osym.put_st_other(vis, 0);
       osym.put_st_shndx(shndx);
@@ -1025,7 +1207,7 @@ Sized_pluginobj<size, big_endian>::do_section_size(unsigned int)
 
 template<int size, bool big_endian>
 std::string
-Sized_pluginobj<size, big_endian>::do_section_name(unsigned int)
+Sized_pluginobj<size, big_endian>::do_section_name(unsigned int) const
 {
   gold_unreachable();
   return std::string();
@@ -1034,13 +1216,14 @@ Sized_pluginobj<size, big_endian>::do_section_name(unsigned int)
 // Return a view of the contents of a section.  Not used for plugin objects.
 
 template<int size, bool big_endian>
-Object::Location
-Sized_pluginobj<size, big_endian>::do_section_contents(unsigned int)
+const unsigned char*
+Sized_pluginobj<size, big_endian>::do_section_contents(
+    unsigned int,
+    section_size_type*,
+    bool)
 {
-  Location loc(0, 0);
-
   gold_unreachable();
-  return loc;
+  return NULL;
 }
 
 // Return section flags.  Not used for plugin objects.
@@ -1123,14 +1306,18 @@ Sized_pluginobj<size, big_endian>::do_initialize_xindex()
   return NULL;
 }
 
-// Get symbol counts.  Not used for plugin objects.
+// Get symbol counts.  Don't count plugin objects; the replacement
+// files will provide the counts.
 
 template<int size, bool big_endian>
 void
-Sized_pluginobj<size, big_endian>::do_get_global_symbol_counts(const Symbol_table*,
-                                                   size_t*, size_t*) const
+Sized_pluginobj<size, big_endian>::do_get_global_symbol_counts(
+    const Symbol_table*,
+    size_t* defined,
+    size_t* used) const
 {
-  gold_unreachable();
+  *defined = 0;
+  *used = 0;
 }
 
 // Get symbols.  Not used for plugin objects.
@@ -1226,7 +1413,6 @@ Plugin_hook::run(Workqueue* workqueue)
                                              this,
                                              this->input_objects_,
                                              this->symtab_,
-                                             this->layout_,
                                              this->dirpath_,
                                              this->mapfile_,
                                              &this->this_blocker_);
@@ -1320,11 +1506,31 @@ static enum ld_plugin_status
 get_symbols(const void* handle, int nsyms, ld_plugin_symbol* syms)
 {
   gold_assert(parameters->options().has_plugins());
-  Pluginobj* obj = parameters->options().plugins()->object(
-      static_cast<unsigned int>(reinterpret_cast<intptr_t>(handle)));
+  Object* obj = parameters->options().plugins()->object(
+    static_cast<unsigned int>(reinterpret_cast<intptr_t>(handle)));
   if (obj == NULL)
     return LDPS_ERR;
-  return obj->get_symbol_resolution_info(nsyms, syms);
+  Pluginobj* plugin_obj = obj->pluginobj();
+  if (plugin_obj == NULL)
+    return LDPS_ERR;
+  return plugin_obj->get_symbol_resolution_info(nsyms, syms, 1);
+}
+
+// Version 2 of the above.  The only difference is that this version
+// is allowed to return the resolution code LDPR_PREVAILING_DEF_IRONLY_EXP.
+
+static enum ld_plugin_status
+get_symbols_v2(const void* handle, int nsyms, ld_plugin_symbol* syms)
+{
+  gold_assert(parameters->options().has_plugins());
+  Object* obj = parameters->options().plugins()->object(
+    static_cast<unsigned int>(reinterpret_cast<intptr_t>(handle)));
+  if (obj == NULL)
+    return LDPS_ERR;
+  Pluginobj* plugin_obj = obj->pluginobj();
+  if (plugin_obj == NULL)
+    return LDPS_ERR;
+  return plugin_obj->get_symbol_resolution_info(nsyms, syms, 2);
 }
 
 // Add a new (real) input file generated by a plugin.
@@ -1384,6 +1590,214 @@ message(int level, const char* format, ...)
   return LDPS_OK;
 }
 
+// Get the section count of the object corresponding to the handle.  This
+// plugin interface can only be called in the claim_file handler of the plugin.
+
+static enum ld_plugin_status
+get_input_section_count(const void* handle, unsigned int* count)
+{
+  gold_assert(parameters->options().has_plugins());
+
+  if (!parameters->options().plugins()->in_claim_file_handler())
+    return LDPS_ERR;
+
+  Object* obj = parameters->options().plugins()->get_elf_object(handle);
+
+  if (obj == NULL)
+    return LDPS_ERR;
+
+  *count = obj->shnum();
+  return LDPS_OK;
+}
+
+// Get the type of the specified section in the object corresponding
+// to the handle.  This plugin interface can only be called in the
+// claim_file handler of the plugin.
+
+static enum ld_plugin_status
+get_input_section_type(const struct ld_plugin_section section,
+                       unsigned int* type)
+{
+  gold_assert(parameters->options().has_plugins());
+
+  if (!parameters->options().plugins()->in_claim_file_handler())
+    return LDPS_ERR;
+
+  Object* obj
+    = parameters->options().plugins()->get_elf_object(section.handle); 
+
+  if (obj == NULL)
+    return LDPS_BAD_HANDLE;
+
+  *type = obj->section_type(section.shndx);
+  return LDPS_OK;
+}
+
+// Get the name of the specified section in the object corresponding
+// to the handle.  This plugin interface can only be called in the
+// claim_file handler of the plugin.
+
+static enum ld_plugin_status
+get_input_section_name(const struct ld_plugin_section section,
+                       char** section_name_ptr)
+{
+  gold_assert(parameters->options().has_plugins());
+
+  if (!parameters->options().plugins()->in_claim_file_handler())
+    return LDPS_ERR;
+
+  Object* obj
+    = parameters->options().plugins()->get_elf_object(section.handle); 
+
+  if (obj == NULL)
+    return LDPS_BAD_HANDLE;
+
+  // Check if the object is locked before getting the section name.
+  gold_assert(obj->is_locked());
+
+  const std::string section_name = obj->section_name(section.shndx);
+  *section_name_ptr = static_cast<char*>(malloc(section_name.length() + 1));
+  memcpy(*section_name_ptr, section_name.c_str(), section_name.length() + 1);
+  return LDPS_OK;
+}
+
+// Get the contents of the specified section in the object corresponding
+// to the handle.  This plugin interface can only be called in the
+// claim_file handler of the plugin.
+
+static enum ld_plugin_status
+get_input_section_contents(const struct ld_plugin_section section,
+                          const unsigned char** section_contents_ptr,
+                          size_t* len)
+{
+  gold_assert(parameters->options().has_plugins());
+
+  if (!parameters->options().plugins()->in_claim_file_handler())
+    return LDPS_ERR;
+
+  Object* obj
+    = parameters->options().plugins()->get_elf_object(section.handle); 
+
+  if (obj == NULL)
+    return LDPS_BAD_HANDLE;
+
+  // Check if the object is locked before getting the section contents.
+  gold_assert(obj->is_locked());
+
+  section_size_type plen;
+  *section_contents_ptr
+      = obj->section_contents(section.shndx, &plen, false);
+  *len = plen;
+  return LDPS_OK;
+}
+
+// Specify the ordering of sections in the final layout. The sections are
+// specified as (handle,shndx) pairs in the two arrays in the order in
+// which they should appear in the final layout.
+
+static enum ld_plugin_status
+update_section_order(const struct ld_plugin_section* section_list,
+                    unsigned int num_sections)
+{
+  gold_assert(parameters->options().has_plugins());
+
+  if (num_sections == 0)
+    return LDPS_OK;
+
+  if (section_list == NULL)
+    return LDPS_ERR;
+
+  Layout* layout = parameters->options().plugins()->layout();
+  gold_assert (layout != NULL);
+
+  std::map<Section_id, unsigned int>* order_map
+    = layout->get_section_order_map();
+
+  /* Store the mapping from Section_id to section position in layout's
+     order_map to consult after output sections are added.  */
+  for (unsigned int i = 0; i < num_sections; ++i)
+    {
+      Object* obj = parameters->options().plugins()->get_elf_object(
+          section_list[i].handle);
+      if (obj == NULL)
+       return LDPS_BAD_HANDLE;
+      unsigned int shndx = section_list[i].shndx;
+      Section_id secn_id(obj, shndx);
+      (*order_map)[secn_id] = i + 1;
+    }
+
+  return LDPS_OK;
+}
+
+// Let the linker know that the sections could be reordered.
+
+static enum ld_plugin_status
+allow_section_ordering()
+{
+  gold_assert(parameters->options().has_plugins());
+  Layout* layout = parameters->options().plugins()->layout();
+  layout->set_section_ordering_specified();
+  return LDPS_OK;
+}
+
+// Let the linker know that a subset of sections could be mapped
+// to a unique segment.
+
+static enum ld_plugin_status
+allow_unique_segment_for_sections()
+{
+  gold_assert(parameters->options().has_plugins());
+  Layout* layout = parameters->options().plugins()->layout();
+  layout->set_unique_segment_for_sections_specified();
+  return LDPS_OK;
+}
+
+// This function should map the list of sections specified in the
+// SECTION_LIST to a unique segment.  ELF segments do not have names
+// and the NAME is used to identify Output Section which should contain
+// the list of sections.  This Output Section will then be mapped to
+// a unique segment.  FLAGS is used to specify if any additional segment
+// flags need to be set.  For instance, a specific segment flag can be
+// set to identify this segment.  Unsetting segment flags is not possible.
+// ALIGN specifies the alignment of the segment.
+
+static enum ld_plugin_status
+unique_segment_for_sections(const char* segment_name,
+                           uint64_t flags,
+                           uint64_t align,
+                           const struct ld_plugin_section* section_list,
+                           unsigned int num_sections)
+{
+  gold_assert(parameters->options().has_plugins());
+
+  if (num_sections == 0)
+    return LDPS_OK;
+
+  if (section_list == NULL)
+    return LDPS_ERR;
+
+  Layout* layout = parameters->options().plugins()->layout();
+  gold_assert (layout != NULL);
+
+  Layout::Unique_segment_info* s = new Layout::Unique_segment_info;
+  s->name = segment_name;
+  s->flags = flags;
+  s->align = align;
+
+  for (unsigned int i = 0; i < num_sections; ++i)
+    {
+      Object* obj = parameters->options().plugins()->get_elf_object(
+          section_list[i].handle);
+      if (obj == NULL)
+       return LDPS_BAD_HANDLE;
+      unsigned int shndx = section_list[i].shndx;
+      Const_section_id secn_id(obj, shndx);
+      layout->insert_section_segment_map(secn_id, s);
+    }
+
+  return LDPS_OK;
+}
+
 #endif // ENABLE_PLUGINS
 
 // Allocate a Pluginobj object of the appropriate size and endianness.