invoke_xmethod & array_view

This replaces more pointer+length with gdb::array_view.  This time,
around invoke_xmethod, and then propagating the fallout around, which
inevitably leaks to the overload resolution code.

There are several places in the code that want to grab a slice of an
array, by advancing the array pointer, and decreasing the length
pointer.  This patch introduces a pair of new
gdb::array_view::slice(...) methods to make that convenient and clear.
Unit test included.

gdb/ChangeLog:
2018-11-21  Pedro Alves  <palves@redhat.com>

	* common/array-view.h (array_view::splice(size_type, size_t)): New.
	(array_view::splice(size_type)): New.
	* eval.c (eval_call, evaluate_funcall): Adjust to use array_view.
	* extension.c (xmethod_worker::get_arg_types): Adjust to return an
	std::vector.
	(xmethod_worker::get_result_type): Adjust to use gdb::array_view.
	* extension.h: Include "common/array-view.h".
	(xmethod_worker::invoke): Adjust to use gdb::array_view.
	(xmethod_worker::get_arg_types): Adjust to return an std::vector.
	(xmethod_worker::get_result_type): Adjust to use gdb::array_view.
	(xmethod_worker::do_get_arg_types): Adjust to use std::vector.
	(xmethod_worker::do_get_result_type): Adjust to use
	gdb::array_view.
	* gdbtypes.c (rank_function): Adjust to use gdb::array_view.
	* gdbtypes.h: Include "common/array-view.h".
	(rank_function): Adjust to use gdb::array_view.
	* python/py-xmethods.c (python_xmethod_worker::invoke)
	(python_xmethod_worker::do_get_arg_types)
	(python_xmethod_worker::do_get_result_type)
	(python_xmethod_worker::invoke): Adjust to new interfaces.
	* valarith.c (value_user_defined_cpp_op, value_user_defined_op)
	(value_x_binop, value_x_unop): Adjust to use gdb::array_view.
	* valops.c (find_overload_match, find_oload_champ_namespace)
	(find_oload_champ_namespace_loop, find_oload_champ): Adjust to use
	gdb:array_view and the new xmethod_worker interfaces.
	* value.c (result_type_of_xmethod, call_xmethod): Adjust to use
	gdb::array_view.
	* value.h (find_overload_match, result_type_of_xmethod)
	(call_xmethod): Adjust to use gdb::array_view.
	* unittests/array-view-selftests.c: Add slicing tests.

1 files changed, 9 insertions, 5 deletions

diff --git a/gdb/eval.c b/gdb/eval.c
index 6eb210d..cb40867 100644
--- a/gdb/eval.c
+++ b/gdb/eval.c
@@ -789,7 +789,9 @@ eval_call (expression *exp, enum noside noside,
       else if (TYPE_CODE (ftype) == TYPE_CODE_XMETHOD)
 	{
 	  type *return_type
-	    = result_type_of_xmethod (argvec[0], nargs, argvec + 1);
+	    = result_type_of_xmethod (argvec[0],
+				      gdb::make_array_view (argvec + 1,
+							    nargs));
 
 	  if (return_type == NULL)
 	    error (_("Xmethod is missing return type."));
@@ -827,7 +829,7 @@ eval_call (expression *exp, enum noside noside,
       return call_internal_function (exp->gdbarch, exp->language_defn,
 				     argvec[0], nargs, argvec + 1);
     case TYPE_CODE_XMETHOD:
-      return call_xmethod (argvec[0], nargs, argvec + 1);
+      return call_xmethod (argvec[0], gdb::make_array_view (argvec + 1, nargs));
     default:
       return call_function_by_hand (argvec[0], default_return_type,
 				    gdb::make_array_view (argvec + 1, nargs));
@@ -1100,7 +1102,8 @@ evaluate_funcall (type *expect_type, expression *exp, int *pos,
       func_name = (char *) alloca (name_len + 1);
       strcpy (func_name, &exp->elts[string_pc + 1].string);
 
-      find_overload_match (&argvec[1], nargs, func_name,
+      find_overload_match (gdb::make_array_view (&argvec[1], nargs),
+			   func_name,
 			   NON_METHOD, /* not method */
 			   NULL, NULL, /* pass NULL symbol since
 					  symbol is unknown */
@@ -1136,7 +1139,8 @@ evaluate_funcall (type *expect_type, expression *exp, int *pos,
 	     evaluation.  */
 	  struct value *valp = NULL;
 
-	  (void) find_overload_match (&argvec[1], nargs, tstr,
+	  (void) find_overload_match (gdb::make_array_view (&argvec[1], nargs),
+				      tstr,
 				      METHOD, /* method */
 				      &arg2,  /* the object */
 				      NULL, &valp, NULL,
@@ -1207,7 +1211,7 @@ evaluate_funcall (type *expect_type, expression *exp, int *pos,
 	  if (op == OP_VAR_VALUE)
 	    function = exp->elts[save_pos1+2].symbol;
 
-	  (void) find_overload_match (&argvec[1], nargs,
+	  (void) find_overload_match (gdb::make_array_view (&argvec[1], nargs),
 				      NULL,        /* no need for name */
 				      NON_METHOD,  /* not method */
 				      NULL, function, /* the function */