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.

2 files changed, 47 insertions, 2 deletions

diff --git a/libgcc/gcov.h b/libgcc/gcov.h
index cea9302..cdd4206 100644
--- a/libgcc/gcov.h
+++ b/libgcc/gcov.h
@@ -43,7 +43,8 @@ extern void __gcov_dump (void);
    stream.  The ALLOCATE_FN callback shall allocate memory with a size in
    characters specified by the first callback parameter.  The ARG parameter is
    a user-provided argument passed as the last argument to the callback
-   functions.  */
+   functions.  It is recommended to use the __gcov_filename_to_gcfn()
+   in the filename callback function.  */
 
 extern void
 __gcov_info_to_gcda (const struct gcov_info *__info,
@@ -52,4 +53,18 @@ __gcov_info_to_gcda (const struct gcov_info *__info,
 		     void *(*__allocate_fn) (unsigned, void *),
 		     void *__arg);
 
+/* Convert the FILENAME to a gcfn data stream.  The DUMP_FN callback is
+   subsequently called with chunks (the begin and length of the chunk are
+   passed as the first two callback parameters) of the gcfn data stream.
+   The ARG parameter is a user-provided argument passed as the last
+   argument to the DUMP_FN callback function.  This function is intended
+   to be used by the filename callback of __gcov_info_to_gcda().  The gcfn
+   data stream is used by the merge-stream subcommand of the gcov-tool to
+   get the filename associated with a gcda data stream.  */
+
+extern void
+__gcov_filename_to_gcfn (const char *__filename,
+			 void (*__dump_fn) (const void *, unsigned, void *),
+			 void *__arg);
+
 #endif /* GCC_GCOV_H */
diff --git a/libgcc/libgcov-driver.c b/libgcc/libgcov-driver.c
index 10831e8..d4517d2 100644
--- a/libgcc/libgcov-driver.c
+++ b/libgcc/libgcov-driver.c
@@ -410,6 +410,23 @@ dump_counter (gcov_type counter,
     dump_unsigned (0, dump_fn, arg);
 }
 
+/* Dump the STRING using the DUMP handler called with ARG.  */
+
+static inline void
+dump_string (const char *string,
+	     void (*dump_fn) (const void *, unsigned, void *),
+	     void *arg)
+{
+  unsigned length = 0;
+
+  if (string)
+    length = strlen (string) + 1;
+
+  dump_unsigned (length, dump_fn, arg);
+  if (string)
+    (*dump_fn) (string, length, arg);
+}
+
 #define MAX(X,Y) ((X) > (Y) ? (X) : (Y))
 
 /* Store all TOP N counters where each has a dynamic length.  */
@@ -768,7 +785,7 @@ __gcov_init (struct gcov_info *info)
 
 #ifdef NEED_L_GCOV_INFO_TO_GCDA
 /* Convert the gcov info to a gcda data stream.  It is intended for
-   free-standing environments which do not support the C library file I/O.  */
+   freestanding environments which do not support the C library file I/O.  */
 
 void
 __gcov_info_to_gcda (const struct gcov_info *gi_ptr,
@@ -780,4 +797,17 @@ __gcov_info_to_gcda (const struct gcov_info *gi_ptr,
   (*filename_fn) (gi_ptr->filename, arg);
   write_one_data (gi_ptr, NULL, dump_fn, allocate_fn, arg);
 }
+
+/* Convert the filename to a gcfn data stream.  It is intended for
+   freestanding environments which do not support the C library file I/O.  */
+
+void
+__gcov_filename_to_gcfn (const char *filename,
+			 void (*dump_fn) (const void *, unsigned, void *),
+			 void *arg)
+{
+  dump_unsigned (GCOV_FILENAME_MAGIC, dump_fn, arg);
+  dump_unsigned (GCOV_VERSION, dump_fn, arg);
+  dump_string (filename, dump_fn, arg);
+}
 #endif /* NEED_L_GCOV_INFO_TO_GCDA */