[Patch, libgfortran] PR59700 and PR59764 Misleading/buggy runtime error message

[Jerry DeLisle]

The attached patch fixes both these bugs, combining Steve's patch and mine.
Recent fixes of memory leaks placed the free_line before the generation of the
error messages rather than after,  The item_count which identifies the read list
item involved with the error was getting cleared, resulting in a faulty error
message.  This is fixed by moving the free_line location to after the message
string is created (before issuing the error still).

The second issue is the variable item_count was being used for two separate
purposes and collided in the case of read_logical.  This was a known issue from
several years ago. Fixed by adjusting the dtp structure just a bit. I used a
spare bit for the expanded_read flag and then used the integer slot made
available for a new variable line_buffer_pos. The new variable name is an
accurate description of what it does, not confused with "item_count".

Regression tested on x86-64.

OK for trunk?  I will add the test case from PR59700 to the test suite.

Regards,

Jerry


2014-01-10  Jerry DeLisle  <jvdelisle@gcc.gnu>
	    Steven G. Kargl  <kargl@gcc.gnu.org>

	PR libfortran/59700
	PR libfortran/59764
	* io/io.h (struct st_parameter_dt): Assign expanded_read flag to
	unused bit. Define new variable line_buffer_pos.
	* io/list_read.c (free_saved, next_char, l_push_char,
	read_logical, read_real): Replace use of item_count with
	line_buffer_pos for line_buffer look ahead.
	(read_logical, read_integer, parse_real, read_real, check_type):
	Adjust location of free_line to after generating error messages
	to retain the correct item count for the message.
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