gcov: Add __gcov_filename_to_gcfn()

gcc/

	* doc/invoke.texi (fprofile-info-section): Mention
	__gcov_filename_to_gcfn().  Use "freestanding" to match with C11
	standard language.  Fix minor example code issues.
	* gcov-io.h (GCOV_FILENAME_MAGIC): Define and document.

gcc/testsuite/

	* gcc.dg/gcov-info-to-gcda.c: Test __gcov_filename_to_gcfn().

libgcc/

	* gcov.h (__gcov_info_to_gcda): Mention __gcov_filename_to_gcfn().
	(__gcov_filename_to_gcfn): Declare and document.
	* libgcov-driver.c (dump_string): New.
	(__gcov_filename_to_gcfn): Likewise.
	(__gcov_info_to_gcda): Adjust comment to match C11 standard language.

3 files changed, 58 insertions, 28 deletions

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index b2d2cea..7cff38b 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -15462,7 +15462,7 @@ profile information generated by @option{-fprofile-arcs} 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.  This option is not intended to be
-used in hosted environments such as GNU/Linux.  It targets free-standing
+used in hosted environments such as GNU/Linux.  It targets freestanding
 environments (for example embedded systems) with limited resources which do not
 support constructors/destructors or the C library file I/O.
 
@@ -15487,14 +15487,8 @@ for example like this:
 #include <stdio.h>
 #include <stdlib.h>
 
-extern const struct gcov_info *__gcov_info_start[];
-extern const struct gcov_info *__gcov_info_end[];
-
-static void
-filename (const char *f, void *arg)
-@{
-  puts (f);
-@}
+extern const struct gcov_info *const __gcov_info_start[];
+extern const struct gcov_info *const __gcov_info_end[];
 
 static void
 dump (const void *d, unsigned n, void *arg)
@@ -15505,6 +15499,12 @@ dump (const void *d, unsigned n, void *arg)
     printf ("%02x", c[i]);
 @}
 
+static void
+filename (const char *f, void *arg)
+@{
+  __gcov_filename_to_gcfn (f, dump, arg );
+@}
+
 static void *
 allocate (unsigned length, void *arg)
 @{
@@ -15514,8 +15514,8 @@ allocate (unsigned length, void *arg)
 static void
 dump_gcov_info (void)
 @{
-  const struct gcov_info **info = __gcov_info_start;
-  const struct gcov_info **end = __gcov_info_end;
+  const struct gcov_info *const *info = __gcov_info_start;
+  const struct gcov_info *const *end = __gcov_info_end;
 
   /* Obfuscate variable to prevent compiler optimizations.  */
   __asm__ ("" : "+r" (info));
@@ -15530,9 +15530,9 @@ dump_gcov_info (void)
 @}
 
 int
-main()
+main (void)
 @{
-  dump_gcov_info();
+  dump_gcov_info ();
   return 0;
 @}
 @end smallexample
diff --git a/gcc/gcov-io.h b/gcc/gcov-io.h
index 204ae0c..3094763 100644
--- a/gcc/gcov-io.h
+++ b/gcc/gcov-io.h
@@ -60,14 +60,21 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 
    	file : int32:magic int32:version int32:stamp record*
 
-   The magic ident is different for the notes and the data files.  The
-   magic ident is used to determine the endianness of the file, when
-   reading.  The version is the same for both files and is derived
-   from gcc's version number. The stamp value is used to synchronize
-   note and data files and to synchronize merging within a data
-   file. It need not be an absolute time stamp, merely a ticker that
-   increments fast enough and cycles slow enough to distinguish
-   different compile/run/compile cycles.
+   A filename header may be used to provide a filename for the data in
+   a stream of data to support gcov in freestanding environments.  This
+   header is used by the merge-stream subcommand of the gcov-tool.  The
+   format of the filename header is
+
+	filename-header : int32:magic int32:version string
+
+   The magic ident is different for the notes and the data files as
+   well as the filename header.  The magic ident is used to determine
+   the endianness of the file, when reading.  The version is the same
+   for both files and is derived from gcc's version number. The stamp
+   value is used to synchronize note and data files and to synchronize
+   merging within a data file. It need not be an absolute time stamp,
+   merely a ticker that increments fast enough and cycles slow enough
+   to distinguish different compile/run/compile cycles.
 
    Although the ident and version are formally 32 bit numbers, they
    are derived from 4 character ASCII strings.  The version number
@@ -228,6 +235,7 @@ typedef uint64_t gcov_type_unsigned;
 /* File magic. Must not be palindromes.  */
 #define GCOV_DATA_MAGIC ((gcov_unsigned_t)0x67636461) /* "gcda" */
 #define GCOV_NOTE_MAGIC ((gcov_unsigned_t)0x67636e6f) /* "gcno" */
+#define GCOV_FILENAME_MAGIC ((gcov_unsigned_t)0x6763666e) /* "gcfn" */
 
 #include "version.h"
 
diff --git a/gcc/testsuite/gcc.dg/gcov-info-to-gcda.c b/gcc/testsuite/gcc.dg/gcov-info-to-gcda.c
index 4583360..ca9b3e8 100644
--- a/gcc/testsuite/gcc.dg/gcov-info-to-gcda.c
+++ b/gcc/testsuite/gcc.dg/gcov-info-to-gcda.c
@@ -17,16 +17,20 @@ __gcov_info_to_gcda (const struct gcov_info *__info,
 		     void *(*__allocate_fn) (unsigned, void *),
 		     void *__arg);
 
+extern void
+__gcov_filename_to_gcfn (const char *__filename,
+			 void (*__dump_fn) (const void *, unsigned, void *),
+			 void *__arg);
+
 extern const struct gcov_info *my_info;
 
 static unsigned counter;
 
-static void
-filename (const char *f, void *arg)
-{
-  assert (arg == &counter);
-  assert (__builtin_strstr (f, "gcov-info-to-gcda.c") == 0);
-}
+static unsigned counter_after_filename;
+
+static int check_zero;
+
+static int check_after_filename;
 
 static void
 dump (const void *d, unsigned n, void *arg)
@@ -37,12 +41,28 @@ dump (const void *d, unsigned n, void *arg)
   if (*m == 0)
   {
     const unsigned *u = d;
+    assert (*u == 0x6763666e);
+    check_zero = 1;
+  }
+  else if (*m == counter_after_filename)
+  {
+    const unsigned *u = d;
     assert (*u == 0x67636461);
+    check_after_filename = 1;
   }
 
   *m += n;
 }
 
+static void
+filename (const char *f, void *arg)
+{
+  assert (arg == &counter);
+  assert (__builtin_strstr (f, "gcov-info-to-gcda.c") == 0);
+  __gcov_filename_to_gcfn (f, dump, arg);
+  counter_after_filename = counter;
+}
+
 static void *
 allocate (unsigned length, void *arg)
 {
@@ -54,6 +74,8 @@ int main()
 {
   __asm__ volatile (".set my_info, .LPBX2");
   __gcov_info_to_gcda (my_info, filename, dump, allocate, &counter);
-  assert (counter > 4);
+  assert (counter > 8);
+  assert (check_zero);
+  assert (check_after_filename);
   return 0;
 }