Use gdb:array_view in call_function_by_hand & friends

This replaces a few uses of pointer+length with gdb::array_view, in
call_function_by_hand and related code.

Unfortunately, due to -Wnarrowing, there are places where we can't
brace-initialize an gdb::array_view without an ugly-ish cast.  To
avoid the cast, this patch introduces a gdb::make_array_view function.
Unit tests included.

This patch in isolation may not look so interesting, due to
gdb::make_array_view uses, but I think it's still worth it.  Some of
the gdb::make_array_view calls disappear down the series, and others
could be eliminated with more (non-trivial) gdb::array_view
detangling/conversion (e.g. code around eval_call).  See this as a "we
have to start somewhere" patch.

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

	* ada-lang.c (ada_evaluate_subexp): Adjust to pass an array_view.
	* common/array-view.h (make_array_view): New.
	* compile/compile-object-run.c (compile_object_run): Adjust to
	pass an array_view.
	* elfread.c (elf_gnu_ifunc_resolve_addr): Adjust.
	* eval.c (eval_call): Adjust to pass an array_view.
	(evaluate_subexp_standard): Adjust to pass an array_view.
	* gcore.c (call_target_sbrk): Adjust to pass an array_view.
	* guile/scm-value.c (gdbscm_value_call): Likewise.
	* infcall.c (push_dummy_code): Replace pointer + size parameters
	with an array_view parameter.
	(call_function_by_hand, call_function_by_hand_dummy): Likewise and
	adjust.
	* infcall.h: Include "common/array-view.h".
	(call_function_by_hand, call_function_by_hand_dummy): Replace
	pointer + size parameters with an array_view parameter.
	* linux-fork.c (inferior_call_waitpid): Adjust to use array_view.
	* linux-tdep.c (linux_infcall_mmap): Likewise.
	* objc-lang.c (lookup_objc_class, lookup_child_selector)
	(value_nsstring, print_object_command): Likewise.
	* python/py-value.c (valpy_call): Likewise.
	* rust-lang.c (rust_evaluate_funcall): Likewise.
	* spu-tdep.c (flush_ea_cache): Likewise.
	* valarith.c (value_x_binop, value_x_unop): Likewise.
	* valops.c (value_allocate_space_in_inferior): Likewise.
	* unittests/array-view-selftests.c (run_tests): Add
	gdb::make_array_view test.

1 files changed, 7 insertions, 8 deletions

diff --git a/gdb/infcall.h b/gdb/infcall.h
index 8b21950..c6b451c 100644
--- a/gdb/infcall.h
+++ b/gdb/infcall.h
@@ -21,6 +21,7 @@
 #define INFCALL_H
 
 #include "dummy-frame.h"
+#include "common/array-view.h"
 
 struct value;
 struct type;
@@ -37,10 +38,10 @@ extern CORE_ADDR find_function_addr (struct value *function,
 
 /* Perform a function call in the inferior.
 
-   ARGS is a vector of values of arguments (NARGS of them).  FUNCTION
-   is a value, the function to be called.  Returns a value
-   representing what the function returned.  May fail to return, if a
-   breakpoint or signal is hit during the execution of the function.
+   ARGS is a vector of values of arguments.  FUNCTION is a value, the
+   function to be called.  Returns a value representing what the
+   function returned.  May fail to return, if a breakpoint or signal
+   is hit during the execution of the function.
 
    DFEAULT_RETURN_TYPE is used as function return type if the return
    type is unknown.  This is used when calling functions with no debug
@@ -50,8 +51,7 @@ extern CORE_ADDR find_function_addr (struct value *function,
 
 extern struct value *call_function_by_hand (struct value *function,
 					    type *default_return_type,
-					    int nargs,
-					    struct value **args);
+					    gdb::array_view<value *> args);
 
 /* Similar to call_function_by_hand and additional call
    register_dummy_frame_dtor with DUMMY_DTOR and DUMMY_DTOR_DATA for the
@@ -60,8 +60,7 @@ extern struct value *call_function_by_hand (struct value *function,
 extern struct value *
   call_function_by_hand_dummy (struct value *function,
 			       type *default_return_type,
-			       int nargs,
-			       struct value **args,
+			       gdb::array_view<value *> args,
 			       dummy_frame_dtor_ftype *dummy_dtor,
 			       void *dummy_dtor_data);