gold patch committed: Implement --print-output-format

[Ian Lance Taylor <iant at google dot com>]

This patch implements --print-output-format for gold.  Committed to
mainline.

Ian


2011-07-15  Ian Lance Taylor  <iant@google.com>

	* options.h (class General_options): Add --print-output-format.
	Move -EL next to -EB, for  better --help output.
	* target-select.cc: Include <cstdio>, "options.h", and
	"parameters.h".
	(Target_selector::do_target_bfd_name): New function.
	(print_output_format): New function.
	* target-select.h (class Target_selector): Update declarations.
	(Target_selector::target_bfd_name): New function.
	(print_output_format): Declare.
	* main.cc: Include "target-select.h".
	(main): Handle --print-output-format.
	* gold.cc: Include "target-select.h".
	(queue_initial_tasks): Handle --print-output-format when there are
	no input files.
	* parameters.cc (parameters_force_valid_target): Give a better
	error message if -EB/-EL does not match target.
	* freebsd.h (Target_selector_freebsd::do_target_bfd_name): New
	function.


Index: freebsd.h
===================================================================
RCS file: /cvs/src/src/gold/freebsd.h,v
retrieving revision 1.6
diff -u -p -r1.6 freebsd.h
--- freebsd.h	28 Jun 2011 23:12:31 -0000	1.6
+++ freebsd.h	15 Jul 2011 21:42:05 -0000
@@ -80,6 +80,17 @@ class Target_selector_freebsd : public T
     names->push_back(this->freebsd_bfd_name_);
   }
 
+  // Return appropriate BFD name.
+  virtual const char*
+  do_target_bfd_name(const Target* target)
+  {
+    if (!this->is_our_target(target))
+      return NULL;
+    return (target->osabi() == elfcpp::ELFOSABI_FREEBSD
+	    ? this->freebsd_bfd_name_
+	    : this->bfd_name_);
+  }
+
  private:
   // The BFD name for the non-Freebsd target.
   const char* bfd_name_;
Index: gold.cc
===================================================================
RCS file: /cvs/src/src/gold/gold.cc,v
retrieving revision 1.93
diff -u -p -r1.93 gold.cc
--- gold.cc	9 Jun 2011 18:18:44 -0000	1.93
+++ gold.cc	15 Jul 2011 21:42:05 -0000
@@ -1,6 +1,6 @@
 // gold.cc -- main linker functions
 
-// Copyright 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
+// Copyright 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
 // Written by Ian Lance Taylor <iant@google.com>.
 
 // This file is part of gold.
@@ -30,6 +30,7 @@
 #include "libiberty.h"
 
 #include "options.h"
+#include "target-select.h"
 #include "debug.h"
 #include "workqueue.h"
 #include "dirsearch.h"
@@ -175,7 +176,15 @@ queue_initial_tasks(const General_option
 {
   if (cmdline.begin() == cmdline.end())
     {
+      bool is_ok = false;
       if (options.printed_version())
+	is_ok = true;
+      if (options.print_output_format())
+	{
+	  print_output_format();
+	  is_ok = true;
+	}
+      if (is_ok)
 	gold_exit(GOLD_OK);
       gold_fatal(_("no input files"));
     }
Index: main.cc
===================================================================
RCS file: /cvs/src/src/gold/main.cc,v
retrieving revision 1.45
diff -u -p -r1.45 main.cc
--- main.cc	14 Jul 2011 00:55:17 -0000	1.45
+++ main.cc	15 Jul 2011 21:42:05 -0000
@@ -1,6 +1,6 @@
 // main.cc -- gold main function.
 
-// Copyright 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
+// Copyright 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
 // Written by Ian Lance Taylor <iant@google.com>.
 
 // This file is part of gold.
@@ -33,6 +33,7 @@
 
 #include "script.h"
 #include "options.h"
+#include "target-select.h"
 #include "parameters.h"
 #include "errors.h"
 #include "mapfile.h"
@@ -246,6 +247,9 @@ main(int argc, char** argv)
   // Run the main task processing loop.
   workqueue.process(0);
 
+  if (command_line.options().print_output_format())
+    print_output_format();
+
   if (command_line.options().stats())
     {
       Timer::TimeStats elapsed = timer.get_elapsed_time();
Index: options.h
===================================================================
RCS file: /cvs/src/src/gold/options.h,v
retrieving revision 1.168
diff -u -p -r1.168 options.h
--- options.h	11 Jul 2011 16:19:51 -0000	1.168
+++ options.h	15 Jul 2011 21:42:05 -0000
@@ -742,12 +742,12 @@ class General_options
   DEFINE_special(EB, options::ONE_DASH, '\0',
 		 N_("Link big-endian objects."), NULL);
 
-  DEFINE_bool(eh_frame_hdr, options::TWO_DASHES, '\0', false,
-              N_("Create exception frame header"), NULL);
-
   DEFINE_special(EL, options::ONE_DASH, '\0',
 		 N_("Link little-endian objects."), NULL);
 
+  DEFINE_bool(eh_frame_hdr, options::TWO_DASHES, '\0', false,
+              N_("Create exception frame header"), NULL);
+
   DEFINE_bool(enum_size_warning, options::TWO_DASHES, '\0', true, NULL,
 	      N_("(ARM only) Do not warn about objects with incompatible "
 		 "enum sizes"));
@@ -927,6 +927,9 @@ class General_options
   DEFINE_bool(preread_archive_symbols, options::TWO_DASHES, '\0', false,
               N_("Preread archive symbols when multi-threaded"), NULL);
 
+  DEFINE_bool(print_output_format, options::TWO_DASHES, '\0', false,
+	      N_("Print default output format"), NULL);
+
   DEFINE_string(print_symbol_counts, options::TWO_DASHES, '\0', NULL,
 		N_("Print symbols defined and used for each input"),
 		N_("FILENAME"));
Index: parameters.cc
===================================================================
RCS file: /cvs/src/src/gold/parameters.cc,v
retrieving revision 1.37
diff -u -p -r1.37 parameters.cc
--- parameters.cc	6 Jul 2011 21:19:32 -0000	1.37
+++ parameters.cc	15 Jul 2011 21:42:05 -0000
@@ -346,7 +346,13 @@ parameters_force_valid_target()
 				 is_big_endian,
 				 elfcpp::GOLD_DEFAULT_OSABI,
 				 0);
-  gold_assert(target != NULL);
+
+  if (target == NULL)
+    {
+      gold_assert(is_big_endian != GOLD_DEFAULT_BIG_ENDIAN);
+      gold_fatal(_("no supported target for -EB/-EL option"));
+    }
+
   set_parameters_target(target);
 }
 
Index: target-select.cc
===================================================================
RCS file: /cvs/src/src/gold/target-select.cc,v
retrieving revision 1.14
diff -u -p -r1.14 target-select.cc
--- target-select.cc	28 Jun 2011 23:12:31 -0000	1.14
+++ target-select.cc	15 Jul 2011 21:42:05 -0000
@@ -22,9 +22,12 @@
 
 #include "gold.h"
 
+#include <cstdio>
 #include <cstring>
 
 #include "elfcpp.h"
+#include "options.h"
+#include "parameters.h"
 #include "target-select.h"
 
 namespace
@@ -80,6 +83,18 @@ Target_selector::set_target()
   this->instantiated_target_ = this->do_instantiate_target();
 }
 
+// If we instantiated TARGET, return the corresponding BFD name.
+
+const char*
+Target_selector::do_target_bfd_name(const Target* target)
+{
+  if (!this->is_our_target(target))
+    return NULL;
+  const char* my_bfd_name = this->bfd_name();
+  gold_assert(my_bfd_name != NULL);
+  return my_bfd_name;
+}
+
 // Find the target for an ELF file.
 
 Target*
@@ -157,4 +172,46 @@ supported_emulation_names(std::vector<co
     p->supported_emulations(names);
 }
 
+// Implement the --print-output-format option.
+
+void
+print_output_format()
+{
+  if (!parameters->target_valid())
+    {
+      // This case arises when --print-output-format is used with no
+      // input files.  We need to come up with the right string to
+      // print based on the other options.  If the user specified the
+      // format using a --oformat option, use that.  That saves each
+      // target from having to remember the name that was used to
+      // select it.  In other cases, we will just have to ask the
+      // target.
+      if (parameters->options().user_set_oformat())
+	{
+	  const char* bfd_name = parameters->options().oformat();
+	  Target* target = select_target_by_bfd_name(bfd_name);
+	  if (target != NULL)
+	    printf("%s\n", bfd_name);
+	  else
+	    gold_error(_("unrecognized output format %s"), bfd_name);
+	  return;
+	}
+
+      parameters_force_valid_target();
+    }
+
+  const Target* target = &parameters->target();
+  for (Target_selector* p = target_selectors; p != NULL; p = p->next())
+    {
+      const char* bfd_name = p->target_bfd_name(target);
+      if (bfd_name != NULL)
+	{
+	  printf("%s\n", bfd_name);
+	  return;
+	}
+    }
+
+  gold_unreachable();
+}
+
 } // End namespace gold.
Index: target-select.h
===================================================================
RCS file: /cvs/src/src/gold/target-select.h,v
retrieving revision 1.13
diff -u -p -r1.13 target-select.h
--- target-select.h	28 Jun 2011 23:12:31 -0000	1.13
+++ target-select.h	15 Jul 2011 21:42:05 -0000
@@ -140,6 +140,13 @@ class Target_selector
   emulation() const
   { return this->emulation_; }
 
+  // The reverse mapping, for --print-output-format: if we
+  // instantiated TARGET, return our BFD_NAME.  If we did not
+  // instantiate it, return NULL.
+  const char*
+  target_bfd_name(const Target* target)
+  { return this->do_target_bfd_name(target); }
+
  protected:
   // Return an instance of the real target.  This must be implemented
   // by the child class.
@@ -192,10 +199,19 @@ class Target_selector
     emulations->push_back(this->emulation_);
   }
 
+  // Map from target to BFD name.
+  virtual const char*
+  do_target_bfd_name(const Target*);
+
   // Instantiate the target and return it.
   Target*
   instantiate_target();
 
+  // Return whether TARGET is the target we instantiated.
+  bool
+  is_our_target(const Target* target)
+  { return target == this->instantiated_target_; }
+
  private:
   // Set the target.
   void
@@ -249,6 +265,11 @@ supported_target_names(std::vector<const
 extern void
 supported_emulation_names(std::vector<const char*>*);
 
+// Print the output format, for the --print-output-format option.
+
+extern void
+print_output_format();
+
 } // End namespace gold.
 
 #endif // !defined(GOLD_TARGET_SELECT_H)