Re: [PR debug/67192] Fix C loops' back-jump location

[Bernd Schmidt <bschmidt@redhat.com>]

On 10/12/2015 04:04 PM, Andreas Arnez wrote:
> Since r223098 ("Implement -Wmisleading-indentation") the backward-jump
> generated for a C while- or for-loop can get the wrong line number.
> This is because the check for misleading indentation peeks ahead one
> token, advancing input_location to after the loop, and then
> c_finish_loop() creates the back-jump and calls add_stmt(), which
> assigns input_location to the statement by default.
>
> This patch swaps the check for misleading indentation with the finishing
> of the loop, such that input_location still has the right value at the
> time of any invocations of add_stmt().

One could argue that peek_token should not have an effect on 
input_location, and in fact cpp_peek_token seems to take steps that this 
does not happen, but it looks like c_parser_peek_token does not use that 
mechanism. Still,
>
> gcc/testsuite/ChangeLog:
>
> 	PR debug/67192
> 	* gcc.dg/guality/pr67192.c: New test.
>
> gcc/c/ChangeLog:
>
> 	PR debug/67192
> 	* c-parser.c (c_parser_while_statement): Finish the loop before
> 	parsing ahead for misleading indentation.
> 	(c_parser_for_statement): Likewise.

This fix looks simple enough. Ok. (Might want to add noclone to the 
testcase attributes).


Bernd