gcov: Add -fprofile-info-section support

Register the profile information in the specified section instead of using a
constructor/destructor.  A pointer to the profile information generated by
-fprofile-arcs or -ftest-coverage is placed in the specified section for each
translation unit.  This option disables the profile information registration
through a constructor and it disables the profile information processing
through a destructor.

I am not sure how I can test this option.  One approach would be to assemble a
test file, then scan it and check that a .gcov_info section is present and no
__gcov_init() and __gcov_exit() calls are present.  Is there an example for
this in the test suite?

gcc/

	* common.opt (fprofile-info-section): New.
	* coverage.c (build_gcov_info_var_registration): New.
	(coverage_obj_init): Evaluate profile_info_section and use
	build_gcov_info_var_registration().
	* doc/invoke.texi (fprofile-info-section): Document.
	* opts.c (common_handle_option): Process fprofile-info-section
	option.

gcc/testsuite/ChangeLog:

	* gcc.dg/profile-info-section.c: New test.

1 files changed, 4 insertions, 0 deletions

diff --git a/gcc/opts.c b/gcc/opts.c
index ac9972d..5777491 100644
--- a/gcc/opts.c
+++ b/gcc/opts.c
@@ -2596,6 +2596,10 @@ common_handle_option (struct gcc_options *opts,
       SET_OPTION_IF_UNSET (opts, opts_set, flag_ipa_bit_cp, value);
       break;
 
+    case OPT_fprofile_info_section:
+      opts->x_profile_info_section = ".gcov_info";
+      break;
+
     case OPT_fpatchable_function_entry_:
       {
 	char *patch_area_arg = xstrdup (arg);