C++: use an optional vec<location_t> for callsites

This patch extends various call-handling locations within the C++
frontend so that they can accept a possibly NULL vec<location_t> *,
using the location information if available in various diagnostics.

It updates the C++ frontend's parser for this production:

   postfix-expression:
     postfix-expression ( expression-list [opt] )

within cp_parser_postfix_expression so that it captures an
auto_vec<location_t> for the arguments (via
cp_parser_parenthesized_expression_list), and passes that around
within the parser, so that e.g.

  error: invalid conversion from 'int' to 'const char*' [-fpermissive]
     return callee_1 (first, second, third);
                                          ^

becomes:

  error: invalid conversion from 'int' to 'const char*' [-fpermissive]
     return callee_1 (first, second, third);
                             ^~~~~~

The vec<location_t> * are also passed to the arg-checking
code of r251238 ( https://gcc.gnu.org/ml/gcc-patches/2017-08/msg01164.html )
so that -Wformat can underline mismatching arguments for C++.

Doing this for C++ requires handling of the case where the vec<location_t>
from the expression-list needs to be offset by 1 relative to the args due
to the "this" parameter not being part of the expression-list, e.g. in:

  logger->log ("%i %s %i", 100, 101, 102);   [1]
                   ^~           ~~~

hence the patch adds a new "argument_locs" class to be responsible for
this in various places in c-family.

Successfully bootstrapped&regrtested on x86_64-pc-linux-gnu;
OK for trunk?

[1] We don't yet underline the "%s" in C++; I plan to fix that as a
separate patch.

gcc/c-family/ChangeLog:
	* c-common.c (argument_locs::get_param_location): New method.
	(check_function_arguments): Convert param "arglocs" from
	vec<location_t> * to argument_locs.
	* c-common.h (class argument_locs): New class.
	(check_function_arguments): Convert final param from
	vec<location_t> * to argument_locs.
	(check_function_format): Likewise.
	* c-format.c (struct format_check_results): Add ctor; convert
	field "arglocs" from vec<location_t> * to argument_locs.
	(check_function_format): Convert param "arglocs" from
	vec<location_t> * to argument_locs.
	(check_format_info): Likewise.  Use a ctor when initializing
	format_ctx.
	(check_format_arg): Convert local "arglocs" from vec<location_t> *
	to argument_locs.
	(class argument_parser): Likewise for field "arglocs".
	(argument_parser::argument_parser): Likewise.
	(check_format_info_main): Likewise for param "arglocs".
	(check_format_types): Likewise.  Replace logic for looking up
	locations within arglocs with a call to
	argument_locs::get_param_location.

gcc/c/ChangeLog:
	* c-typeck.c (build_function_call_vec): Update for conversion
	of final parameter of check_function_arguments.

gcc/cp/ChangeLog:
	* call.c (print_z_candidate): Add optional "arglocs" param and
	pass it to fn_type_unification.
	(print_z_candidates): Add optional "arglocs" param and pass it to
	print_z_candidate.
	(print_error_for_call_failure): Add optional "arglocs" param and
	pass it to print_z_candidates.
	(build_new_function_call): Add "arglocs" param and
	pass it to print_error_for_call_failure and build_over_call.
	(convert_like_real): Convert param "expr" from tree to cp_expr.
	(build_over_call): Add optional "arglocs" param.  Use it if
	available when calling convert_like_with_context, by converting
	"arg" to a cp_expr. Use arglocs when calling
	check_function_arguments, determining the appropriate offset to
	use based on whether there was a "first_arg".
	(build_new_method_call_1): Add "arglocs" param and pass it to
	build_over_call.
	(build_new_method_call): Add "arglocs" param and pass it to
	build_new_method_call_1.
	* cp-tree.h (build_new_function_call): Add optional
	vec<location_t> * param.
	(build_new_method_call): Likewise.
	(fn_type_unification): Likewise.
	(finish_call_expr): Likewise.
	(cp_build_function_call_vec): Likewise.
	* parser.c (cp_parser_postfix_expression): Within handling of
	"postfix-expression ( expression-list [opt] )" production, add
	auto_vec<location_t> and pass it to be built to
	cp_parser_parenthesized_expression_list; pass it for use to
	calls to build_new_method_call and finish_call_expr.
	(cp_parser_parenthesized_expression_list): Add optional "arglocs"
	param.  Convert local "expr" to cp_expr, using it to populate
	"arglocs" if non-NULL.
	* pt.c (unify_type_mismatch): Convert final param from tree to
	cp_expr to fix the location of the "inform".
	(unify_arg_conversion): Likewise.
	(fn_type_unification): Add "arglocs" param and pass it to
	type_unification_real.
	(check_non_deducible_conversion): Convert "arg" from tree to
	cp_expr.
	(type_unification_real): Add optional "arglocs" param.
	Convert local "arg" from tree to cp_expr, reading its location
	from arglocs, or, failing that, from input_location.
	* semantics.c (finish_call_expr): Add optional
	vec<location_t> * param and pass to calls to build_new_method_call
	and build_new_function_call.
	* typeck.c (cp_build_function_call_vec): Add optional
	vec<location_t> * param and pass to call to
	check_function_arguments.

gcc/testsuite/ChangeLog:
	* g++.dg/Wformat-on-method.C: New test case.
	* g++.dg/diagnostic/param-type-mismatch.C: Update expected results
	to reflect underlining of pertinent arguments.
---
 gcc/c-family/c-common.c                            | 27 +++++++-
 gcc/c-family/c-common.h                            | 39 ++++++++++-
 gcc/c-family/c-format.c                            | 53 ++++++++-------
 gcc/c/c-typeck.c                                   |  3 +-
 gcc/cp/call.c                                      | 77 ++++++++++++++--------
 gcc/cp/cp-tree.h                                   | 15 +++--
 gcc/cp/parser.c                                    | 30 ++++++---
 gcc/cp/pt.c                                        | 54 ++++++++++-----
 gcc/cp/semantics.c                                 |  9 +--
 gcc/cp/typeck.c                                    |  6 +-
 gcc/testsuite/g++.dg/Wformat-on-method.C           | 31 +++++++++
 .../g++.dg/diagnostic/param-type-mismatch.C        | 18 ++---
 12 files changed, 261 insertions(+), 101 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/Wformat-on-method.C

C++: use an optional vec<location_t> for callsites

Commit Message

Patch