PR 47793 - Support relative paths using -fprofile-generate (issue4434055)

[Martin Thuresson]

This is slightly updated from my previous patch proposal. The test now
correctly work if multiple tests are executed in parallell.

2011-04-17  Martin Thuresson  <martint@google.com>

	* gcc/doc/invoke.tex: Document support for relative profile paths.
	* gcc/testsuite/gcc.dg/pr47793.c: New test.
	* gcc/libgcov.c	(gcov_exit): Support relative profile paths.

Index: gcc/doc/invoke.texi
===================================================================
--- gcc/doc/invoke.texi	(revision 172439)
+++ gcc/doc/invoke.texi	(working copy)
@@ -7751,7 +7751,7 @@ Set the directory to search for the prof
 This option affects only the profile data generated by
 @option{-fprofile-generate}, @option{-ftest-coverage}, @option{-fprofile-arcs}
 and used by @option{-fprofile-use} and @option{-fbranch-probabilities}
-and its related options.
+and its related options.  Both absolute and relative paths can be used.
 By default, GCC will use the current directory as @var{path}, thus the
 profile data file will appear in the same directory as the object file.
 
Index: gcc/testsuite/gcc.dg/pr47793.c
===================================================================
--- gcc/testsuite/gcc.dg/pr47793.c	(revision 0)
+++ gcc/testsuite/gcc.dg/pr47793.c	(revision 0)
@@ -0,0 +1,12 @@
+/* Bug pr47793: Allow relative paths in profile-generate.  */
+/* { dg-do run } */
+/* { dg-options "-O -fprofile-generate=./" } */
+/* { dg-final { scan-file pr47793.gcda "."} } */
+
+int
+main(void)
+{
+  return 0;
+}
+
+/* { dg-final { cleanup-coverage-files } } */
Index: gcc/libgcov.c
===================================================================
--- gcc/libgcov.c	(revision 172439)
+++ gcc/libgcov.c	(working copy)
@@ -283,8 +283,9 @@ gcov_exit (void)
 	      }
         }
       /* Update complete filename with stripped original. */
-      if (!IS_DIR_SEPARATOR (*fname) && !HAS_DRIVE_SPEC(fname))
-	{
+      if (prefix_length != 0 && !IS_DIR_SEPARATOR (*fname))
+        {
+          /* If prefix is given, add directory separator.  */
 	  strcpy (gi_filename_up, "/");
 	  strcpy (gi_filename_up + 1, fname);
 	}

--
This patch is available for review at http://codereview.appspot.com/4434055