gas/
[deliverable/binutils-gdb.git] / gold / layout.cc
index 9d4b644d112195890e94e2ad78729a4b9d6c1c26..83c8c6a025587200936bb66e321463b006ba194c 100644 (file)
@@ -1,5 +1,25 @@
 // layout.cc -- lay out output file sections for gold
 
+// Copyright 2006, 2007 Free Software Foundation, Inc.
+// Written by Ian Lance Taylor <iant@google.com>.
+
+// This file is part of gold.
+
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
+// MA 02110-1301, USA.
+
 #include "gold.h"
 
 #include <cstring>
@@ -11,6 +31,7 @@
 #include "output.h"
 #include "symtab.h"
 #include "dynobj.h"
+#include "ehframe.h"
 #include "layout.h"
 
 namespace gold
@@ -45,7 +66,8 @@ Layout::Layout(const General_options& options)
     section_name_map_(), segment_list_(), section_list_(),
     unattached_section_list_(), special_output_list_(),
     tls_segment_(NULL), symtab_section_(NULL),
-    dynsym_section_(NULL), dynamic_section_(NULL), dynamic_data_(NULL)
+    dynsym_section_(NULL), dynamic_section_(NULL), dynamic_data_(NULL),
+    eh_frame_section_(NULL)
 {
   // Make space for more than enough segments for a typical file.
   // This is just for efficiency--it's OK if we wind up needing more.
@@ -186,6 +208,17 @@ Layout::layout(Relobj* object, unsigned int shndx, const char* name,
                                                shdr.get_sh_type(),
                                                shdr.get_sh_flags());
 
+  // Special GNU handling of sections named .eh_frame.
+  if (!parameters->output_is_object()
+      && strcmp(name, ".eh_frame") == 0
+      && shdr.get_sh_size() > 0
+      && shdr.get_sh_type() == elfcpp::SHT_PROGBITS
+      && shdr.get_sh_flags() == elfcpp::SHF_ALLOC)
+    {
+      this->layout_eh_frame(object, shndx, name, shdr, os, off);
+      return os;
+    }
+
   // FIXME: Handle SHF_LINK_ORDER somewhere.
 
   *off = os->add_input_section(object, shndx, name, shdr);
@@ -193,6 +226,46 @@ Layout::layout(Relobj* object, unsigned int shndx, const char* name,
   return os;
 }
 
+// Special GNU handling of sections named .eh_frame.  They will
+// normally hold exception frame data.
+
+template<int size, bool big_endian>
+void
+Layout::layout_eh_frame(Relobj* object,
+                       unsigned int shndx,
+                       const char* name,
+                       const elfcpp::Shdr<size, big_endian>& shdr,
+                       Output_section* os, off_t* off)
+{
+  if (this->eh_frame_section_ == NULL)
+    {
+      this->eh_frame_section_ = os;
+
+      if (this->options_.create_eh_frame_hdr())
+       {
+         Stringpool::Key hdr_name_key;
+         const char* hdr_name = this->namepool_.add(".eh_frame_hdr",
+                                                    &hdr_name_key);
+         Output_section* hdr_os =
+           this->get_output_section(hdr_name, hdr_name_key,
+                                    elfcpp::SHT_PROGBITS,
+                                    elfcpp::SHF_ALLOC);
+
+         Eh_frame_hdr* hdr_posd = new Eh_frame_hdr(os);
+         hdr_os->add_output_section_data(hdr_posd);
+
+         Output_segment* hdr_oseg =
+           new Output_segment(elfcpp::PT_GNU_EH_FRAME, elfcpp::PF_R);
+         this->segment_list_.push_back(hdr_oseg);
+         hdr_oseg->add_output_section(hdr_os, elfcpp::PF_R);
+       }
+    }
+
+  gold_assert(this->eh_frame_section_ == os);
+
+  *off = os->add_input_section(object, shndx, name, shdr);
+}
+
 // Add POSD to an output section using NAME, TYPE, and FLAGS.
 
 void
@@ -331,12 +404,63 @@ Layout::create_initial_dynamic_sections(const Input_objects* input_objects,
                                elfcpp::STT_OBJECT, elfcpp::STB_LOCAL,
                                elfcpp::STV_HIDDEN, 0, false, false);
 
-  this->dynamic_data_ =  new Output_data_dynamic(input_objects->target(),
-                                                &this->dynpool_);
+  this->dynamic_data_ =  new Output_data_dynamic(&this->dynpool_);
 
   this->dynamic_section_->add_output_section_data(this->dynamic_data_);
 }
 
+// For each output section whose name can be represented as C symbol,
+// define __start and __stop symbols for the section.  This is a GNU
+// extension.
+
+void
+Layout::define_section_symbols(Symbol_table* symtab, const Target* target)
+{
+  for (Section_list::const_iterator p = this->section_list_.begin();
+       p != this->section_list_.end();
+       ++p)
+    {
+      const char* const name = (*p)->name();
+      if (name[strspn(name,
+                     ("0123456789"
+                      "ABCDEFGHIJKLMNOPWRSTUVWXYZ"
+                      "abcdefghijklmnopqrstuvwxyz"
+                      "_"))]
+         == '\0')
+       {
+         const std::string name_string(name);
+         const std::string start_name("__start_" + name_string);
+         const std::string stop_name("__stop_" + name_string);
+
+         symtab->define_in_output_data(target,
+                                       start_name.c_str(),
+                                       NULL, // version
+                                       *p,
+                                       0, // value
+                                       0, // symsize
+                                       elfcpp::STT_NOTYPE,
+                                       elfcpp::STB_GLOBAL,
+                                       elfcpp::STV_DEFAULT,
+                                       0, // nonvis
+                                       false, // offset_is_from_end
+                                       false); // only_if_ref
+
+         symtab->define_in_output_data(target,
+                                       stop_name.c_str(),
+                                       NULL, // version
+                                       *p,
+                                       0, // value
+                                       0, // symsize
+                                       elfcpp::STT_NOTYPE,
+                                       elfcpp::STB_GLOBAL,
+                                       elfcpp::STV_DEFAULT,
+                                       0, // nonvis
+                                       true, // offset_is_from_end
+                                       false); // only_if_ref
+       }
+    }
+}
+
 // Find the first read-only PT_LOAD segment, creating one if
 // necessary.
 
@@ -394,7 +518,6 @@ off_t
 Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab)
 {
   Target* const target = input_objects->target();
-  const int size = target->get_size();
 
   target->finalize_sections(this);
 
@@ -432,7 +555,7 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab)
 
       // Create the version sections.  We can't do this until the
       // dynamic string table is complete.
-      this->create_version_sections(target, &versions, local_dynamic_count,
+      this->create_version_sections(&versions, local_dynamic_count,
                                    dynamic_symbols, dynstr);
     }
 
@@ -441,10 +564,8 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab)
   Output_segment* load_seg = this->find_first_load_seg();
 
   // Lay out the segment headers.
-  bool big_endian = target->is_big_endian();
   Output_segment_headers* segment_headers;
-  segment_headers = new Output_segment_headers(size, big_endian,
-                                              this->segment_list_);
+  segment_headers = new Output_segment_headers(this->segment_list_);
   load_seg->add_initial_output_data(segment_headers);
   this->special_output_list_.push_back(segment_headers);
   if (phdr_seg != NULL)
@@ -452,11 +573,7 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab)
 
   // Lay out the file header.
   Output_file_header* file_header;
-  file_header = new Output_file_header(size,
-                                      big_endian,
-                                      target,
-                                      symtab,
-                                      segment_headers);
+  file_header = new Output_file_header(target, symtab, segment_headers);
   load_seg->add_initial_output_data(file_header);
   this->special_output_list_.push_back(file_header);
 
@@ -469,7 +586,7 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab)
   off_t off = this->set_segment_offsets(target, load_seg, &shndx);
 
   // Create the symbol table sections.
-  this->create_symtab_sections(size, input_objects, symtab, &off);
+  this->create_symtab_sections(input_objects, symtab, &off);
 
   // Create the .shstrtab section.
   Output_section* shstrtab_section = this->create_shstrtab();
@@ -479,7 +596,7 @@ Layout::finalize(const Input_objects* input_objects, Symbol_table* symtab)
   off = this->set_section_offsets(off, &shndx);
 
   // Create the section table header.
-  Output_section_headers* oshdrs = this->create_shdrs(size, big_endian, &off);
+  Output_section_headers* oshdrs = this->create_shdrs(&off);
 
   file_header->set_section_info(oshdrs, shstrtab_section);
 
@@ -701,18 +818,18 @@ Layout::set_section_offsets(off_t off, unsigned int* pshndx)
 // fully laid out.
 
 void
-Layout::create_symtab_sections(int size, const Input_objects* input_objects,
+Layout::create_symtab_sections(const Input_objects* input_objects,
                               Symbol_table* symtab,
                               off_t* poff)
 {
   int symsize;
   unsigned int align;
-  if (size == 32)
+  if (parameters->get_size() == 32)
     {
       symsize = elfcpp::Elf_sizes<32>::sym_size;
       align = 4;
     }
-  else if (size == 64)
+  else if (parameters->get_size() == 64)
     {
       symsize = elfcpp::Elf_sizes<64>::sym_size;
       align = 8;
@@ -835,10 +952,10 @@ Layout::create_shstrtab()
 // offset.
 
 Output_section_headers*
-Layout::create_shdrs(int size, bool big_endian, off_t* poff)
+Layout::create_shdrs(off_t* poff)
 {
   Output_section_headers* oshdrs;
-  oshdrs = new Output_section_headers(size, big_endian, this,
+  oshdrs = new Output_section_headers(this,
                                      &this->segment_list_,
                                      &this->unattached_section_list_,
                                      &this->namepool_);
@@ -895,7 +1012,7 @@ Layout::create_dynamic_symtab(const Target* target, Symbol_table* symtab,
 
   int symsize;
   unsigned int align;
-  const int size = target->get_size();
+  const int size = parameters->get_size();
   if (size == 32)
     {
       symsize = elfcpp::Elf_sizes<32>::sym_size;
@@ -954,7 +1071,7 @@ Layout::create_dynamic_symtab(const Target* target, Symbol_table* symtab,
 
   unsigned char* phash;
   unsigned int hashlen;
-  Dynobj::create_elf_hash_table(target, *pdynamic_symbols, local_symcount,
+  Dynobj::create_elf_hash_table(*pdynamic_symbols, local_symcount,
                                &phash, &hashlen);
 
   const char* hash_name = this->namepool_.add(".hash", NULL);
@@ -976,7 +1093,7 @@ Layout::create_dynamic_symtab(const Target* target, Symbol_table* symtab,
 // Create the version sections.
 
 void
-Layout::create_version_sections(const Target* target, const Versions* versions,
+Layout::create_version_sections(const Versions* versions,
                                unsigned int local_symcount,
                                const std::vector<Symbol*>& dynamic_symbols,
                                const Output_section* dynstr)
@@ -984,9 +1101,9 @@ Layout::create_version_sections(const Target* target, const Versions* versions,
   if (!versions->any_defs() && !versions->any_needs())
     return;
 
-  if (target->get_size() == 32)
+  if (parameters->get_size() == 32)
     {
-      if (target->is_big_endian())
+      if (parameters->is_big_endian())
         {
 #ifdef HAVE_TARGET_32_BIG
           this->sized_create_version_sections
@@ -1009,9 +1126,9 @@ Layout::create_version_sections(const Target* target, const Versions* versions,
 #endif
         }
     }
-  else if (target->get_size() == 64)
+  else if (parameters->get_size() == 64)
     {
-      if (target->is_big_endian())
+      if (parameters->is_big_endian())
         {
 #ifdef HAVE_TARGET_64_BIG
           this->sized_create_version_sections
@@ -1344,7 +1461,7 @@ Layout::add_comdat(const char* signature, bool group)
   else if (group)
     {
       // This is a real section group, and we've already seen a
-      // linkonce section with tihs signature.  Record that we've seen
+      // linkonce section with this signature.  Record that we've seen
       // a section group, and don't include this section group.
       ins.first->second = true;
       return false;
@@ -1361,8 +1478,7 @@ Layout::add_comdat(const char* signature, bool group)
 // Write out data not associated with a section or the symbol table.
 
 void
-Layout::write_data(const Symbol_table* symtab, const Target* target,
-                  Output_file* of) const
+Layout::write_data(const Symbol_table* symtab, Output_file* of) const
 {
   const Output_section* symtab_section = this->symtab_section_;
   for (Section_list::const_iterator p = this->section_list_.begin();
@@ -1376,7 +1492,7 @@ Layout::write_data(const Symbol_table* symtab, const Target* target,
          gold_assert(index > 0 && index != -1U);
          off_t off = (symtab_section->offset()
                       + index * symtab_section->entsize());
-         symtab->write_section_symbol(target, *p, of, off);
+         symtab->write_section_symbol(*p, of, off);
        }
     }
 
@@ -1392,7 +1508,7 @@ Layout::write_data(const Symbol_table* symtab, const Target* target,
          gold_assert(index > 0 && index != -1U);
          off_t off = (dynsym_section->offset()
                       + index * dynsym_section->entsize());
-         symtab->write_section_symbol(target, *p, of, off);
+         symtab->write_section_symbol(*p, of, off);
        }
     }
 
@@ -1435,7 +1551,7 @@ Write_data_task::locks(Workqueue* workqueue)
 void
 Write_data_task::run(Workqueue*)
 {
-  this->layout_->write_data(this->symtab_, this->target_, this->of_);
+  this->layout_->write_data(this->symtab_, this->of_);
 }
 
 // Write_symbols_task methods.
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