Patch to do reorder text and data sections according to a user specified sequence.

Sriraman Tallam tmsriram@google.com
Fri May 14 00:58:00 GMT 2010
Hi Ian and Taras,

     Sorry for taking this long to get back. I have modified the patch
to address Taras' timing issue. Basically, I split patterns specified
into glob and non-glob by just looking for wild-card characters in the
pattern. Non-glob look-ups are through a hash table and fast. Glob
patterns are be searched linearly. So, if you specify non-glob symbol
names in the section ordering file, the link should be faster than
before.

     Further, I have prioritized non-glob patters over glob patterns.
Let me explain with an example :

If object main.o has sections .text._foov, .text._barv, and
.text._zapv and the seection ordering file is :
===============================
*bar*
.text.*
.text._barv
===============================

Then, .text._barv will be the last section in .text even though it
matches the first glob pattern.


The changes are :

	* gold.h (is_wildcard_string): New function.
	* layout.cc (Layout::layout): Pass this pointer to add_input_section.
	(Layout::layout_eh_frame): Ditto.
	(Layout::find_section_order_index): New method.
	(Layout::read_layout_from_file): New method.
	* layout.h (Layout::find_section_order_index): New method.
	(Layout::read_layout_from_file): New method.
	(Layout::input_section_position_): New private member.
	(Layout::input_section_glob_): New private member.
	* main.cc (main): Call read_layout_from_file here.
	* options.h (--section-ordering-file): New option.
	* output.cc (Output_section::input_section_order_specified_): New
	member.
	(Output_section::Output_section): Initialize new member.
	(Output_section::add_input_section): Add new parameter.
	Keep input sections when --section-ordering-file is used.
	(Output_section::set_final_data_size): Sort input sections when
	section ordering file is specified.
	(Output_section::Input_section_sort_entry): Add new parameter.
	Check sorting type.
	(Output_section::Input_section_sort_entry::is_before_in_sequence):
	New method.
	(Output_section::Input_section_sort_compare::operator()): Change to
	consider section_order_index.
	(Output_section::Input_section_sort_init_fini_compare::operator()):
	Change to consider section_order_index.
	(Output_section::Input_section_sort_section_order_index_compare
	::operator()): New method.
	(Output_section::sort_attached_input_sections): Change to sort
	according to section order when specified.
	(Output_section::add_input_section<32, true>): Add new parameter.
	(Output_section::add_input_section<64, true>): Add new parameter.
	(Output_section::add_input_section<32, false>): Add new parameter.
	(Output_section::add_input_section<64, false>): Add new parameter.
	* output.h (Output_section::add_input_section): Add new parameter.
	(Output_section::input_section_order_specified): New
	method.
	(Output_section::set_input_section_order_specified): New method.
	(Input_section::Input_section): Initialize section_order_index_.
	(Input_section::section_order_index): New method.
	(Input_section::set_section_order_index): New method.
	(Input_section::section_order_index_): New member.
	(Input_section::Input_section_sort_section_order_index_compare): New
	struct.
	(Output_section::input_section_order_specified_): New member.
	* script-sections.cc (is_wildcard_string): Delete and move modified
	method to gold.h.
	(Output_section_element_input::Output_section_element_input): Modify
	call to is_wildcard_string.
	(Output_section_element_input::Input_section_pattern
	::Input_section_pattern): Ditto.
	(Output_section_element_input::Output_section_element_input): Ditto.
	* testsuite/Makefile.am (final_layout): New test case.
	* testsuite/Makefile.in: Regenerate.
	* testsuite/final_layout.cc: New file.
	* testsuite/final_layout.sh: New file.

Please let me know what you think.

Thanks,
-Sri.



On Tue, Mar 2, 2010 at 7:43 PM, Sriraman Tallam <tmsriram@google.com> wrote:
> Hi Ian,
>
>    I finally got around to making the changes you specified. Please
> take a look when you get a chance.
>
>        * layout.cc (Layout::read_layout_from_file): New method.
>        (Layout::layout): Pass this pointer to add_input_section.
>        (Layout::layout_eh_frame): Ditto.
>        * layout.h (Layout::read_layout_from_file): New method.
>        (Layout::input_section_order): New method.
>        (Layout::input_section_order_): New private member.
>        * main.cc (main): Call read_layout_from_file here.
>        * options.h (--section-ordering-file): New option.
>        * output.cc (Output_section::input_section_order_specified_): New
>        member.
>        (Output_section::add_input_section): Add new parameter.
>        Keep input sections when --section-ordering-file is used.
>        (Output_section::set_final_data_size): Sort input sections when
>        section ordering file is specified.
>        (Output_section::Input_section_sort_entry::section_order_index_): New
>        member.
>        (Output_section::Input_section_sort_entry::section_order_index): New
>        method.
>        (Output_section::Input_section_sort_compare::operator()): Change to
>        consider section_order_index.
>        (Output_section::Input_section_sort_init_fini_compare::operator()):
>        Change to consider section_order_index.
>        (Output_section::Input_section_sort_section_order_index_compare
>        ::operator()): New method.
>        (Output_section::sort_attached_input_sections): Change to sort
>        according to section order when specified.
>        * output.h (Output_section::input_section_order_specified): New
>        method.
>        (Output_section::set_input_section_order_specified): New method.
>        (Input_section::glob_pattern_number): New method.
>        (Input_section::set_glob_pattern_number): New method.
>        (Input_section::glob_pattern_number_): New member.
>        (Input_section::Input_section_sort_section_order_index_compare): New
>        struct.
>        (Output_section::input_section_order_specified_): New member.
>        * testsuite/Makefile.am (final_layout): New test case.
>        * testsuite/Makefile.in: Regenerate.
>        * testsuite/final_layout.cc: New file.
>        * testsuite/final_layout.sh: New file
>
>
> Thanks,
> -Sriraman.
>
>
> On Thu, Feb 11, 2010 at 9:29 PM, Ian Lance Taylor <iant@google.com> wrote:
>> Sriraman Tallam <tmsriram@google.com> writes:
>>
>>>    I have attached a patch to reorder text and data sections in the
>>> linker according to a user specified sequence. I have added a new
>>> option --final-layout to do this. Currently, this could be done using
>>> linker scripts but this patch makes it really easy to do this. Let me
>>> explain using a simple example.
>>>
>>> test.cc
>>>
>>> void foo()
>>> { }
>>>
>>> void bar()
>>> { }
>>>
>>> int main()
>>> {
>>>   return 0;
>>> }
>>>
>>> $ g++ -ffunction-sections test.cc
>>> $ nm -n a.out
>>> ...
>>> 000000000040038c T _Z3foov
>>> 0000000000400392 T _Z3barv
>>> ....
>>>
>>> foo is laid to be before bar. Now, I can change this order as follows.
>>>
>>> $ (echo "_Z3barv" && echo "_Z3foov") > sequence.txt
>>> $ g++ -ffunction-sections test.cc -Wl,--final-layout,sequence.txt
>>> $ nm -n a.out
>>> ...
>>> 0000000000400658 T _Z3barv
>>> 000000000040065e T _Z3foov
>>> ...
>>>
>>> The order is changed.
>>>
>>> This can be done for text or data sections.
>>
>>
>> As I understand it, in linker terms, you are sorting the sections by
>> suffixes.  When two input sections are in the same output section, and
>> both input sections have suffixes which appear in the file, then the
>> input sections are sorted in the order in which the suffixes appear in
>> the file.
>>
>> I think it would be more natural to sort the input sections by name
>> rather than by suffix.  Since you don't want to fuss with writing
>> ".text." all the time, suppose we say that we sort the input sections
>> by name, and we match the input section names using glob patterns.  We
>> already use glob patterns in linker scripts, so that is not a big
>> stretch.
>>
>> Just a few comments on the rest of the patch.
>>
>>
>>
>>> +// Read the sequence of input sections from the file specified with
>>> +// --final-layout.
>>> +
>>> +bool
>>> +Layout::read_layout_from_file()
>>> +{
>>> +  const char* filename = parameters->options().final_layout();
>>> +  char *buf = NULL;
>>> +  size_t len = 0;
>>> +  FILE* fp = fopen(filename, "r");
>>> +
>>> +  if (fp == NULL)
>>> +    {
>>> +      gold_error(_("Error opening layout file : %s\n"), filename);
>>> +      gold_exit(false);
>>> +    }
>>> +
>>> +  while (getline(&buf, &len, fp) != -1)
>>> +    {
>>> +      buf[strlen(buf) - 1] = 0;
>>> +      this->input_section_order_.push_back(std::string(buf));
>>> +    }
>>> +
>>> +  if (buf != NULL)
>>> +    free(buf);
>>> +
>>> +  fclose(fp);
>>> +  return true;
>>> +}
>>
>> The getline function is insufficient portable for use in gold.  Search
>> for std::getline in options.cc for an alternate approach you can use.
>> Emulate the error message style you see there too--no capital letter,
>> name the file, no space before colon, no \n.  And if you really want
>> to exit on failure, call gold_fatal.
>>
>>
>>> +// If --final-layout option is used, reorder the input sections in
>>> +// .text, .data, .bss and .rodata according to the specified sequence.
>>> +
>>> +void
>>> +Layout::section_reorder()
>>> +{
>>> +  this->read_layout_from_file();
>>> +
>>> +  for (Section_list::iterator p = this->section_list_.begin();
>>> +       p != this->section_list_.end();
>>> +       ++p)
>>> +    {
>>> +      if (strcmp(".text", (*p)->name()) == 0
>>> +          || strcmp(".data", (*p)->name()) == 0
>>> +          || strcmp(".bss", (*p)->name()) == 0
>>> +          || strcmp(".rodata", (*p)->name()) == 0)
>>> +        (*p)->reorder_layout(this);
>>> +    }
>>> +}
>>
>> Why restrict this to those output sections?  Why not sort input
>> sections in any output section?
>>
>>
>>> +  DEFINE_string(final_layout, options::TWO_DASHES, '\0', NULL,
>>> +             N_("Layout functions and data in the order specified."),
>>> +             N_("FILENAME"));
>>
>> I'm not sure I care for --final-layout as the option name.  Perhaps
>> --section-ordering-file?  Perhaps somebody else has a better idea.
>>
>>
>>> +  // the future, we keep track of the sections.  If the --final-layout
>>> +  // option is used to specify the order of sections, we need to keep
>>> +  // track of sections.
>>>    if (have_sections_script
>>>        || !this->input_sections_.empty()
>>>        || this->may_sort_attached_input_sections()
>>>        || this->must_sort_attached_input_sections()
>>>        || parameters->options().user_set_Map()
>>> -      || parameters->target().may_relax())
>>> -    this->input_sections_.push_back(Input_section(object, shndx,
>>> -                                               shdr.get_sh_size(),
>>> -                                               addralign));
>>> +      || parameters->target().may_relax()
>>> +      || parameters->options().final_layout())
>>> +    {
>>> +      Input_section isecn(object, shndx, shdr.get_sh_size(), addralign);
>>> +      isecn.set_section_name(secname);
>>> +      this->input_sections_.push_back(isecn);
>>> +    }
>>
>> Don't save the string here, that's just going to bloat memory usage.
>> Instead, when you read the file, give each line a number.  Then match
>> the section name which you have here against the list of patterns.  If
>> you find a match, store the number in the Input_section structure.
>> Also, if you find a match, set a flag in the output section.  Then
>> sort the sections, by number, in a function called from
>> set_final_data_size.
>>
>> You will see that there is already some section ordering in that
>> function, which is used to implement constructor/destructor priority
>> ordering.  I guess the priority ordering should take precedence.
>> Maybe.
>>
>> Ian
>>
>
-------------- next part --------------
Index: gold.h
===================================================================
RCS file: /cvs/src/src/gold/gold.h,v
retrieving revision 1.42
diff -u -u -p -r1.42 gold.h
--- gold.h	7 Jan 2010 07:14:29 -0000	1.42
+++ gold.h	14 May 2010 00:48:50 -0000
@@ -401,6 +401,15 @@ string_hash(const Char_type* s)
   return h;
 }
 
+// Return whether STRING contains a wildcard character.  This is used
+// to speed up matching.
+
+inline bool
+is_wildcard_string(const char* s)
+{
+  return strpbrk(s, "?*[") != NULL;
+}
+
 } // End namespace gold.
 
 #endif // !defined(GOLD_GOLD_H)
Index: layout.cc
===================================================================
RCS file: /cvs/src/src/gold/layout.cc,v
retrieving revision 1.169
diff -u -u -p -r1.169 layout.cc
--- layout.cc	24 Apr 2010 14:32:23 -0000	1.169
+++ layout.cc	14 May 2010 00:48:50 -0000
@@ -26,8 +26,10 @@
 #include <cstring>
 #include <algorithm>
 #include <iostream>
+#include <fstream>
 #include <utility>
 #include <fcntl.h>
+#include <fnmatch.h>
 #include <unistd.h>
 #include "libiberty.h"
 #include "md5.h"
@@ -669,7 +671,8 @@ Layout::layout(Sized_relobj<size, big_en
   // FIXME: Handle SHF_LINK_ORDER somewhere.
 
   *off = os->add_input_section(object, shndx, name, shdr, reloc_shndx,
-			       this->script_options_->saw_sections_clause());
+			       this->script_options_->saw_sections_clause(),
+                               this);
   this->have_added_input_section_ = true;
 
   return os;
@@ -887,7 +890,7 @@ Layout::layout_eh_frame(Sized_relobj<siz
       // Add it as a normal section.
       bool saw_sections_clause = this->script_options_->saw_sections_clause();
       *off = os->add_input_section(object, shndx, name, shdr, reloc_shndx,
-				   saw_sections_clause);
+				   saw_sections_clause, this);
       this->have_added_input_section_ = true;
     }
 
@@ -1642,6 +1645,65 @@ Layout::relaxation_loop_body(
   return off;
 }
 
+// Search the list of patterns and find the postion of the given section
+// name in the output section.  If the section name matches a glob
+// pattern and a non-glob name, then the non-glob position takes
+// precedence.  Return 0 if no match is found.
+
+unsigned int
+Layout::find_section_order_index(const std::string& section_name)
+{
+  std::map<std::string, unsigned int>::iterator map_it;
+  map_it = this->input_section_position_.find(section_name);
+  if (map_it != this->input_section_position_.end())
+    return map_it->second;
+  
+  // Absolute match failed.  Linear search the glob patterns.   
+  std::vector<std::string>::iterator it;
+  for (it = this->input_section_glob_.begin();
+       it != this->input_section_glob_.end();
+       ++it)
+    {
+       if (fnmatch((*it).c_str(), section_name.c_str(), FNM_NOESCAPE) == 0)
+         {
+           map_it = this->input_section_position_.find(*it);
+           gold_assert(map_it != this->input_section_position_.end());
+           return map_it->second;
+         }
+    }
+  return 0;
+}
+
+// Read the sequence of input sections from the file specified with
+// --section-ordering-file.
+
+void
+Layout::read_layout_from_file()
+{
+  const char* filename = parameters->options().section_ordering_file();
+  std::ifstream in;
+  std::string line;
+
+  in.open(filename);
+  std::getline(in, line);   // this chops off the trailing \n, if any
+  if (!in)
+    gold_fatal(_("unable to open --section-ordering-file file %s: %s"),
+               filename, strerror(errno));
+
+  unsigned int position = 1;
+  while (in)
+    {
+      if (!line.empty() && line[line.length() - 1] == '\r')   // Windows
+        line.resize(line.length() - 1);
+      this->input_section_position_[line] = position;
+      // Store all glob patterns in a vector.
+      if (is_wildcard_string(line.c_str()))
+        this->input_section_glob_.push_back(line);
+      position++;
+      std::getline(in, line);
+    }
+}
+
 // Finalize the layout.  When this is called, we have created all the
 // output sections and all the output segments which are based on
 // input sections.  We have several things to do, and we have to do
Index: layout.h
===================================================================
RCS file: /cvs/src/src/gold/layout.h,v
retrieving revision 1.80
diff -u -u -p -r1.80 layout.h
--- layout.h	9 Apr 2010 17:32:58 -0000	1.80
+++ layout.h	14 May 2010 00:48:50 -0000
@@ -308,6 +308,12 @@ class Layout
 	 const char* name, const elfcpp::Shdr<size, big_endian>& shdr,
 	 unsigned int reloc_shndx, unsigned int reloc_type, off_t* offset);
 
+  unsigned int
+  find_section_order_index(const std::string&);
+
+  void
+  read_layout_from_file();
+
   // Layout an input reloc section when doing a relocatable link.  The
   // section is RELOC_SHNDX in OBJECT, with data in SHDR.
   // DATA_SECTION is the reloc section to which it refers.  RR is the
@@ -1037,6 +1043,10 @@ class Layout
   Segment_states* segment_states_;
   // A relaxation debug checker.  We only create one when in debugging mode.
   Relaxation_debug_check* relaxation_debug_check_;
+  // Hash a pattern to its position in the section ordering file.
+  std::map<std::string, unsigned int> input_section_position_;
+  // Vector of glob only patterns in the section_ordering file.
+  std::vector<std::string> input_section_glob_;
 };
 
 // This task handles writing out data in output sections which is not
Index: main.cc
===================================================================
RCS file: /cvs/src/src/gold/main.cc,v
retrieving revision 1.38
diff -u -u -p -r1.38 main.cc
--- main.cc	22 Mar 2010 14:18:24 -0000	1.38
+++ main.cc	14 May 2010 00:48:50 -0000
@@ -234,6 +234,9 @@ main(int argc, char** argv)
       layout.incremental_inputs()->report_inputs(command_line.inputs());
     }
 
+  if (parameters->options().section_ordering_file())
+    layout.read_layout_from_file();
+
   // Get the search path from the -L options.
   Dirsearch search_path;
   search_path.initialize(&workqueue, &command_line.options().library_path());
Index: options.h
===================================================================
RCS file: /cvs/src/src/gold/options.h,v
retrieving revision 1.145
diff -u -u -p -r1.145 options.h
--- options.h	21 Apr 2010 16:32:28 -0000	1.145
+++ options.h	14 May 2010 00:48:51 -0000
@@ -888,6 +888,10 @@ class General_options
                  N_("Add DIR to link time shared library search path"),
                  N_("DIR"));
 
+  DEFINE_string(section_ordering_file, options::TWO_DASHES, '\0', NULL,
+		N_("Layout functions and data in the order specified."),
+		N_("FILENAME"));
+
   DEFINE_special(section_start, options::TWO_DASHES, '\0',
 		 N_("Set address of section"), N_("SECTION=ADDRESS"));
 
Index: output.cc
===================================================================
RCS file: /cvs/src/src/gold/output.cc,v
retrieving revision 1.124
diff -u -u -p -r1.124 output.cc
--- output.cc	9 Apr 2010 17:32:58 -0000	1.124
+++ output.cc	14 May 2010 00:48:51 -0000
@@ -29,6 +29,7 @@
 #include <unistd.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
+#include <fnmatch.h>
 #include <algorithm>
 #include "libiberty.h"
 
@@ -1897,6 +1898,7 @@ Output_section::Output_section(const cha
     found_in_sections_clause_(false),
     has_load_address_(false),
     info_uses_section_index_(false),
+    input_section_order_specified_(false),
     may_sort_attached_input_sections_(false),
     must_sort_attached_input_sections_(false),
     attached_input_sections_are_sorted_(false),
@@ -1966,7 +1968,8 @@ Output_section::add_input_section(Sized_
 				  const char* secname,
 				  const elfcpp::Shdr<size, big_endian>& shdr,
 				  unsigned int reloc_shndx,
-				  bool have_sections_script)
+				  bool have_sections_script,
+				  Layout* layout)
 {
   elfcpp::Elf_Xword addralign = shdr.get_sh_addralign();
   if ((addralign & (addralign - 1)) != 0)
@@ -2053,16 +2056,30 @@ Output_section::add_input_section(Sized_
   // We need to keep track of this section if we are already keeping
   // track of sections, or if we are relaxing.  Also, if this is a
   // section which requires sorting, or which may require sorting in
-  // the future, we keep track of the sections.
+  // the future, we keep track of the sections.  If the
+  // --section-ordering-file option is used to specify the order of
+  // sections, we need to keep track of sections.
   if (have_sections_script
       || !this->input_sections_.empty()
       || this->may_sort_attached_input_sections()
       || this->must_sort_attached_input_sections()
       || parameters->options().user_set_Map()
-      || parameters->target().may_relax())
-    this->input_sections_.push_back(Input_section(object, shndx,
-						  shdr.get_sh_size(),
-						  addralign));
+      || parameters->target().may_relax()
+      || parameters->options().section_ordering_file())
+    {
+      Input_section isecn(object, shndx, shdr.get_sh_size(), addralign);
+      if (parameters->options().section_ordering_file())
+        {
+          unsigned int section_order_index =
+            layout->find_section_order_index(std::string(secname));
+	  if (section_order_index)
+            {
+              isecn.set_section_order_index(section_order_index);
+              this->set_input_section_order_specified();
+            }
+        }
+      this->input_sections_.push_back(isecn);
+    }
 
   return aligned_offset_in_section;
 }
@@ -2563,7 +2580,8 @@ Output_section::set_final_data_size()
       return;
     }
 
-  if (this->must_sort_attached_input_sections())
+  if (this->must_sort_attached_input_sections()
+      || this->input_section_order_specified())
     this->sort_attached_input_sections();
 
   uint64_t address = this->address();
@@ -2640,12 +2658,14 @@ class Output_section::Input_section_sort
   { }
 
   Input_section_sort_entry(const Input_section& input_section,
-			   unsigned int index)
+			   unsigned int index,
+			   bool must_sort_attached_input_sections)
     : input_section_(input_section), index_(index),
       section_has_name_(input_section.is_input_section()
 			|| input_section.is_relaxed_input_section())
   {
-    if (this->section_has_name_)
+    if (this->section_has_name_
+        && must_sort_attached_input_sections)
       {
 	// This is only called single-threaded from Layout::finalize,
 	// so it is OK to lock.  Unfortunately we have no way to pass
@@ -2722,6 +2742,18 @@ class Output_section::Input_section_sort
     return memcmp(base_name + base_len - 2, ".o", 2) == 0;
   }
 
+  // Returns 0 if no order is specified. Returns 1 if "this" is the
+  // first section in order (is_before), returns 2 for s.
+  unsigned int
+  is_before_in_sequence(const Input_section_sort_entry& s) const
+  {
+    if (this->input_section_.section_order_index() == 0
+        && s.input_section().section_order_index() == 0)
+      return 0;
+    return (this->input_section_.section_order_index()
+            <= s.input_section().section_order_index());
+  }
+
  private:
   // The Input_section we are sorting.
   Input_section input_section_;
@@ -2783,6 +2815,11 @@ Output_section::Input_section_sort_compa
   if (!s1_has_priority && s2_has_priority)
     return true;
 
+  // Check if a input sequence has been specified.
+  unsigned int sequence_num = s1.is_before_in_sequence(s2);
+  if (sequence_num)
+    return sequence_num == 1;
+
   // Otherwise we sort by name.
   int compare = s1.section_name().compare(s2.section_name());
   if (compare != 0)
@@ -2819,6 +2856,11 @@ Output_section::Input_section_sort_init_
   if (!s1_has_priority && s2_has_priority)
     return false;
 
+  // Check if a input sequence has been specified.
+  unsigned int sequence_num = s1.is_before_in_sequence(s2);
+  if (sequence_num)
+    return sequence_num == 1;
+
   // Otherwise we sort by name.
   int compare = s1.section_name().compare(s2.section_name());
   if (compare != 0)
@@ -2828,6 +2870,21 @@ Output_section::Input_section_sort_init_
   return s1.index() < s2.index();
 }
 
+// Return true if S1 should come before S2.
+bool
+Output_section::Input_section_sort_section_order_index_compare::operator()(
+    const Output_section::Input_section_sort_entry& s1,
+    const Output_section::Input_section_sort_entry& s2) const
+{  
+  // Check if a input sequence has been specified.
+  unsigned int sequence_num = s1.is_before_in_sequence(s2);
+  if (sequence_num)
+    return sequence_num == 1;
+
+  // Otherwise we keep the input order.
+  return s1.index() < s2.index();
+}
+
 // Sort the input sections attached to an output section.
 
 void
@@ -2853,17 +2910,27 @@ Output_section::sort_attached_input_sect
   for (Input_section_list::iterator p = this->input_sections_.begin();
        p != this->input_sections_.end();
        ++p, ++i)
-    sort_list.push_back(Input_section_sort_entry(*p, i));
+    sort_list.push_back(Input_section_sort_entry(*p, i,
+			  this->must_sort_attached_input_sections()));
 
   // Sort the input sections.
-  if (this->type() == elfcpp::SHT_PREINIT_ARRAY
-      || this->type() == elfcpp::SHT_INIT_ARRAY
-      || this->type() == elfcpp::SHT_FINI_ARRAY)
-    std::sort(sort_list.begin(), sort_list.end(),
-	      Input_section_sort_init_fini_compare());
+  if (this->must_sort_attached_input_sections())
+    {
+      if (this->type() == elfcpp::SHT_PREINIT_ARRAY
+          || this->type() == elfcpp::SHT_INIT_ARRAY
+          || this->type() == elfcpp::SHT_FINI_ARRAY)
+        std::sort(sort_list.begin(), sort_list.end(),
+	          Input_section_sort_init_fini_compare());
+      else
+        std::sort(sort_list.begin(), sort_list.end(),
+	          Input_section_sort_compare());
+    }
   else
-    std::sort(sort_list.begin(), sort_list.end(),
-	      Input_section_sort_compare());
+    {
+      gold_assert(parameters->options().section_ordering_file());
+      std::sort(sort_list.begin(), sort_list.end(),
+	        Input_section_sort_section_order_index_compare());
+    }
 
   // Copy the sorted input sections back to our list.
   this->input_sections_.clear();
@@ -4390,7 +4457,8 @@ Output_section::add_input_section<32, fa
     const char* secname,
     const elfcpp::Shdr<32, false>& shdr,
     unsigned int reloc_shndx,
-    bool have_sections_script);
+    bool have_sections_script,
+    Layout* layout);
 #endif
 
 #ifdef HAVE_TARGET_32_BIG
@@ -4402,7 +4470,8 @@ Output_section::add_input_section<32, tr
     const char* secname,
     const elfcpp::Shdr<32, true>& shdr,
     unsigned int reloc_shndx,
-    bool have_sections_script);
+    bool have_sections_script,
+    Layout* layout);
 #endif
 
 #ifdef HAVE_TARGET_64_LITTLE
@@ -4414,7 +4483,8 @@ Output_section::add_input_section<64, fa
     const char* secname,
     const elfcpp::Shdr<64, false>& shdr,
     unsigned int reloc_shndx,
-    bool have_sections_script);
+    bool have_sections_script,
+    Layout* layout);
 #endif
 
 #ifdef HAVE_TARGET_64_BIG
@@ -4426,7 +4496,8 @@ Output_section::add_input_section<64, tr
     const char* secname,
     const elfcpp::Shdr<64, true>& shdr,
     unsigned int reloc_shndx,
-    bool have_sections_script);
+    bool have_sections_script,
+    Layout* layout);
 #endif
 
 #ifdef HAVE_TARGET_32_LITTLE
Index: output.h
===================================================================
RCS file: /cvs/src/src/gold/output.h,v
retrieving revision 1.104
diff -u -u -p -r1.104 output.h
--- output.h	23 Apr 2010 04:47:32 -0000	1.104
+++ output.h	14 May 2010 00:48:51 -0000
@@ -2336,7 +2336,8 @@ class Output_section : public Output_dat
   add_input_section(Sized_relobj<size, big_endian>* object, unsigned int shndx,
 		    const char *name,
 		    const elfcpp::Shdr<size, big_endian>& shdr,
-		    unsigned int reloc_shndx, bool have_sections_script);
+		    unsigned int reloc_shndx, bool have_sections_script,
+		    Layout* layout);
 
   // Add generated data POSD to this output section.
   void
@@ -2554,6 +2555,18 @@ class Output_section : public Output_dat
   set_may_sort_attached_input_sections()
   { this->may_sort_attached_input_sections_ = true; }
 
+  // Returns true if input sections must be sorted according to the
+  // order in which their name appear in the --section-ordering-file.
+  bool
+  input_section_order_specified()
+  { return this->input_section_order_specified_; }
+
+  // Record that input sections must be sorted as some of their names
+  // match the patterns specified through --section-ordering-file.
+  void
+  set_input_section_order_specified()
+  { this->input_section_order_specified_ = true; }
+
   // Return whether the input sections attached to this output section
   // require sorting.  This is used to handle constructor priorities
   // compatibly with GNU ld.
@@ -3047,7 +3060,8 @@ class Output_section : public Output_dat
     Input_section(Relobj* object, unsigned int shndx, off_t data_size,
 		  uint64_t addralign)
       : shndx_(shndx),
-	p2align_(ffsll(static_cast<long long>(addralign)))
+	p2align_(ffsll(static_cast<long long>(addralign))),
+        section_order_index_(0)
     {
       gold_assert(shndx != OUTPUT_SECTION_CODE
 		  && shndx != MERGE_DATA_SECTION_CODE
@@ -3059,7 +3073,8 @@ class Output_section : public Output_dat
 
     // For a non-merge output section.
     Input_section(Output_section_data* posd)
-      : shndx_(OUTPUT_SECTION_CODE), p2align_(0)
+      : shndx_(OUTPUT_SECTION_CODE), p2align_(0),
+        section_order_index_(0)
     {
       this->u1_.data_size = 0;
       this->u2_.posd = posd;
@@ -3070,7 +3085,8 @@ class Output_section : public Output_dat
       : shndx_(is_string
 	       ? MERGE_STRING_SECTION_CODE
 	       : MERGE_DATA_SECTION_CODE),
-	p2align_(0)
+	p2align_(0),
+        section_order_index_(0)
     {
       this->u1_.entsize = entsize;
       this->u2_.posd = posd;
@@ -3078,12 +3094,25 @@ class Output_section : public Output_dat
 
     // For a relaxed input section.
     Input_section(Output_relaxed_input_section *psection)
-      : shndx_(RELAXED_INPUT_SECTION_CODE), p2align_(0)
+      : shndx_(RELAXED_INPUT_SECTION_CODE), p2align_(0),
+        section_order_index_(0)
     {
       this->u1_.data_size = 0;
       this->u2_.poris = psection;
     }
 
+    unsigned int
+    section_order_index() const
+    {
+      return this->section_order_index_;
+    }
+
+    void
+    set_section_order_index(unsigned int number)
+    {
+      this->section_order_index_ = number;  
+    }
+
     // The required alignment.
     uint64_t
     addralign() const
@@ -3292,6 +3321,9 @@ class Output_section : public Output_dat
       // For RELAXED_INPUT_SECTION_CODE, the data.
       Output_relaxed_input_section* poris;
     } u2_;
+    // The line number of the pattern it matches in the --section-ordering-file
+    // file.  It is 0 if does not match any pattern.
+    unsigned int section_order_index_;
   };
 
   typedef std::vector<Input_section> Input_section_list;
@@ -3404,6 +3436,15 @@ class Output_section : public Output_dat
 	       const Input_section_sort_entry&) const;
   };
 
+  // This is the sort comparison function when a section order is specified
+  // from an input file.
+  struct Input_section_sort_section_order_index_compare
+  {
+    bool
+    operator()(const Input_section_sort_entry&,
+	       const Input_section_sort_entry&) const;
+  };
+
   // Fill data.  This is used to fill in data between input sections.
   // It is also used for data statements (BYTE, WORD, etc.) in linker
   // scripts.  When we have to keep track of the input sections, we
@@ -3637,6 +3678,9 @@ class Output_section : public Output_dat
   // section, false if it means the symbol index of the corresponding
   // section symbol.
   bool info_uses_section_index_ : 1;
+  // True if input sections attached to this output section have to be
+  // sorted according to a specified order.
+  bool input_section_order_specified_ : 1;
   // True if the input sections attached to this output section may
   // need sorting.
   bool may_sort_attached_input_sections_ : 1;
Index: script-sections.cc
===================================================================
RCS file: /cvs/src/src/gold/script-sections.cc,v
retrieving revision 1.33
diff -u -u -p -r1.33 script-sections.cc
--- script-sections.cc	23 Apr 2010 04:47:33 -0000	1.33
+++ script-sections.cc	14 May 2010 00:48:51 -0000
@@ -983,15 +983,6 @@ class Output_section_element_fill : publ
   Expression* val_;
 };
 
-// Return whether STRING contains a wildcard character.  This is used
-// to speed up matching.
-
-static inline bool
-is_wildcard_string(const std::string& s)
-{
-  return strpbrk(s.c_str(), "?*[") != NULL;
-}
-
 // An input section specification in an output section
 
 class Output_section_element_input : public Output_section_element
@@ -1035,7 +1026,7 @@ class Output_section_element_input : pub
     Input_section_pattern(const char* patterna, size_t patternlena,
 			  Sort_wildcard sorta)
       : pattern(patterna, patternlena),
-	pattern_is_wildcard(is_wildcard_string(this->pattern)),
+	pattern_is_wildcard(is_wildcard_string(this->pattern.c_str())),
 	sort(sorta)
     { }
   };
@@ -1102,7 +1093,7 @@ Output_section_element_input::Output_sec
   if (spec->file.name.length != 1 || spec->file.name.value[0] != '*')
     this->filename_pattern_.assign(spec->file.name.value,
 				   spec->file.name.length);
-  this->filename_is_wildcard_ = is_wildcard_string(this->filename_pattern_);
+  this->filename_is_wildcard_ = is_wildcard_string(this->filename_pattern_.c_str());
 
   if (spec->input_sections.exclude != NULL)
     {
@@ -1111,7 +1102,7 @@ Output_section_element_input::Output_sec
 	   p != spec->input_sections.exclude->end();
 	   ++p)
 	{
-	  bool is_wildcard = is_wildcard_string(*p);
+	  bool is_wildcard = is_wildcard_string((*p).c_str());
 	  this->filename_exclusions_.push_back(std::make_pair(*p,
 							      is_wildcard));
 	}
cvs diff: Diffing po
cvs diff: Diffing testsuite
Index: testsuite/Makefile.am
===================================================================
RCS file: /cvs/src/src/gold/testsuite/Makefile.am,v
retrieving revision 1.133
diff -u -u -p -r1.133 Makefile.am
--- testsuite/Makefile.am	13 May 2010 02:41:15 -0000	1.133
+++ testsuite/Makefile.am	14 May 2010 00:48:51 -0000
@@ -193,6 +193,18 @@ icf_safe_so_test_1.stdout: icf_safe_so_t
 icf_safe_so_test_2.stdout: icf_safe_so_test
 	$(TEST_READELF) -h icf_safe_so_test > icf_safe_so_test_2.stdout
 
+check_SCRIPTS += final_layout.sh
+check_DATA += final_layout.stdout
+MOSTLYCLEANFILES += final_layout
+final_layout.o: final_layout.cc
+	$(CXXCOMPILE) -O0 -c -ffunction-sections  -fdata-sections -g -o $@ $<
+final_layout_sequence.txt:
+	(echo "*_Z3barv*" && echo ".text._Z3bazv" && echo "*_Z3foov*" && echo "*global_varb*" && echo "*global_vara*" && echo "*global_varc*") > final_layout_sequence.txt
+final_layout: final_layout.o final_layout_sequence.txt gcctestdir/ld
+	$(CXXLINK) -Bgcctestdir/ -Wl,--section-ordering-file,final_layout_sequence.txt final_layout.o
+final_layout.stdout: final_layout
+	$(TEST_NM) final_layout > final_layout.stdout
+
 check_PROGRAMS += icf_virtual_function_folding_test
 MOSTLYCLEANFILES += icf_virtual_function_folding_test
 icf_virtual_function_folding_test.o: icf_virtual_function_folding_test.cc
Index: testsuite/final_layout.cc
===================================================================
RCS file: testsuite/final_layout.cc
diff -N testsuite/final_layout.cc
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ testsuite/final_layout.cc	14 May 2010 00:48:51 -0000
@@ -0,0 +1,48 @@
+// final_layout.cc -- a test case for gold
+
+// Copyright 2010 Free Software Foundation, Inc.
+// Written by Sriraman Tallam <tmsriram@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.
+
+// The goal of this program is to verify if --section-ordering-file orders
+// the .text and .data sections correctly as specified.
+
+int global_vara;
+int global_varb;
+int global_varc;
+
+int foo()
+{
+  return 1;
+}
+
+int bar()
+{
+  return 1;
+}
+
+int baz()
+{
+  return 1;
+}
+
+int main()
+{
+  return 1;
+}
Index: testsuite/final_layout.sh
===================================================================
RCS file: testsuite/final_layout.sh
diff -N testsuite/final_layout.sh
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ testsuite/final_layout.sh	14 May 2010 00:48:51 -0000
@@ -0,0 +1,42 @@
+#!/bin/sh
+
+# final_layout.sh -- test --final-layout
+
+# Copyright 2010 Free Software Foundation, Inc.
+# Written by Sriraman Tallam <tmsriram@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.
+
+# The goal of this program is to verify if --section-ordering-file works as
+# intended.  File final_layout.cc is in this test.
+
+check()
+{
+    func_addr_1=$((16#`grep $2 $1 | awk '{print $1}'`))
+    func_addr_2=$((16#`grep $3 $1 | awk '{print $1}'`))
+    if [ $func_addr_1 -gt $func_addr_2 ]
+    then
+        echo "final layout of" $2 "and" $3 "is not right."
+	exit 1
+    fi
+}
+
+check final_layout.stdout "_Z3barv" "_Z3bazv"
+check final_layout.stdout "_Z3bazv" "_Z3foov"
+check final_layout.stdout "global_varb" "global_vara"
+check final_layout.stdout "global_vara" "global_varc"


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