Re: [PATCH 06/10] Track expression ranges in C frontend

[Jeff Law <law@redhat.com>]

On 10/23/2015 02:41 PM, David Malcolm wrote:
> As in the previous version of this patch
>   "Implement tree expression tracking in C FE (v2)"
> the patch now captures ranges for all C expressions during parsing within
> a new field of c_expr, and for all tree nodes with a location_t, it stores
> them in ad-hoc locations for later use.
>
> Hence compound expressions get ranges; see:
>    https://dmalcolm.fedorapeople.org/gcc/2015-09-22/diagnostic-test-expressions-1.html
>
> and for this example:
>
>    int test (int foo)
>    {
>      return foo * 100;
>             ^^^   ^^^
>    }
>
> we have access to the ranges of "foo" and "100" during C parsing via
> the c_expr, but once we have GENERIC, all we have is a VAR_DECL and an
> INTEGER_CST (the former's location is in at the top of the
> function, and the latter has no location).
>
> gcc/ChangeLog:
> 	* Makefile.in (OBJS): Add gcc-rich-location.o.
> 	* gcc-rich-location.c: New file.
> 	* gcc-rich-location.h: New file.
> 	* print-tree.c (print_node): Print any source range information.
> 	* tree.c (set_source_range): New functions.
> 	* tree.h (CAN_HAVE_RANGE_P): New.
> 	(EXPR_LOCATION_RANGE): New.
> 	(EXPR_HAS_RANGE): New.
> 	(get_expr_source_range): New inline function.
> 	(DECL_LOCATION_RANGE): New.
> 	(set_source_range): New decls.
> 	(get_decl_source_range): New inline function.
>
> gcc/c-family/ChangeLog:
> 	* c-common.c (c_fully_fold_internal): Capture existing souce_range,
> 	and store it on the result.
>
> gcc/c/ChangeLog:
> 	* c-parser.c (set_c_expr_source_range): New functions.
> 	(c_token::get_range): New method.
> 	(c_token::get_finish): New method.
> 	(c_parser_expr_no_commas): Call set_c_expr_source_range on the ret
> 	based on the range from the start of the LHS to the end of the
> 	RHS.
> 	(c_parser_conditional_expression): Likewise, based on the range
> 	from the start of the cond.value to the end of exp2.value.
> 	(c_parser_binary_expression): Call set_c_expr_source_range on
> 	the stack values for TRUTH_ANDIF_EXPR and TRUTH_ORIF_EXPR.
> 	(c_parser_cast_expression): Call set_c_expr_source_range on ret
> 	based on the cast_loc through to the end of the expr.
> 	(c_parser_unary_expression): Likewise, based on the
> 	op_loc through to the end of op.
> 	(c_parser_sizeof_expression) Likewise, based on the start of the
> 	sizeof token through to either the closing paren or the end of
> 	expr.
> 	(c_parser_postfix_expression): Likewise, using the token range,
> 	or from the open paren through to the close paren for
> 	parenthesized expressions.
> 	(c_parser_postfix_expression_after_primary): Likewise, for
> 	various kinds of expression.
> 	* c-tree.h (struct c_expr): Add field "src_range".
> 	(c_expr::get_start): New method.
> 	(c_expr::get_finish): New method.
> 	(set_c_expr_source_range): New decls.
> 	* c-typeck.c (parser_build_unary_op): Call set_c_expr_source_range
> 	on ret for prefix unary ops.
> 	(parser_build_binary_op): Likewise, running from the start of
> 	arg1.value through to the end of arg2.value.
>
> gcc/testsuite/ChangeLog:
> 	* gcc.dg/plugin/diagnostic-test-expressions-1.c: New file.
> 	* gcc.dg/plugin/diagnostic_plugin_test_tree_expression_range.c:
> 	New file.
> 	* gcc.dg/plugin/plugin.exp (plugin_test_list): Add
> 	diagnostic_plugin_test_tree_expression_range.c and
> 	diagnostic-test-expressions-1.c.

>   /* Initialization routine for this file.  */
>
> @@ -6085,6 +6112,9 @@ c_parser_expr_no_commas (c_parser *parser, struct c_expr *after,
>     ret.value = build_modify_expr (op_location, lhs.value, lhs.original_type,
>   				 code, exp_location, rhs.value,
>   				 rhs.original_type);
> +  set_c_expr_source_range (&ret,
> +			   lhs.get_start (),
> +			   rhs.get_finish ());
One line if it fits.


> @@ -6198,6 +6232,9 @@ c_parser_conditional_expression (c_parser *parser, struct c_expr *after,
>   			   ? t1
>   			   : NULL);
>       }
> +  set_c_expr_source_range (&ret,
> +			   start,
> +			   exp2.get_finish ());
Here too.

> @@ -6522,6 +6564,10 @@ c_parser_cast_expression (c_parser *parser, struct c_expr *after)
>   	expr = convert_lvalue_to_rvalue (expr_loc, expr, true, true);
>         }
>         ret.value = c_cast_expr (cast_loc, type_name, expr.value);
> +      if (ret.value && expr.value)
> +	set_c_expr_source_range (&ret,
> +				 cast_loc,
> +				 expr.get_finish ());
And here?

With the nits fixed, this is OK.

I think that covers this iteration of the rich location work and that 
you'll continue working with Jason on extending this into the C++ front-end.

jeff