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, 6 insertions, 7 deletions

diff --git a/gdb/objc-lang.c b/gdb/objc-lang.c
index 6da8af1..d51362a 100644
--- a/gdb/objc-lang.c
+++ b/gdb/objc-lang.c
@@ -132,7 +132,7 @@ lookup_objc_class (struct gdbarch *gdbarch, const char *classname)
   classval = value_coerce_array (classval);
   return (CORE_ADDR) value_as_long (call_function_by_hand (function,
 							   NULL,
-							   1, &classval));
+							   classval));
 }
 
 CORE_ADDR
@@ -160,7 +160,7 @@ lookup_child_selector (struct gdbarch *gdbarch, const char *selname)
   selstring = value_coerce_array (value_string (selname, 
 						strlen (selname) + 1,
 						char_type));
-  return value_as_long (call_function_by_hand (function, NULL, 1, &selstring));
+  return value_as_long (call_function_by_hand (function, NULL, selstring));
 }
 
 struct value * 
@@ -181,13 +181,12 @@ value_nsstring (struct gdbarch *gdbarch, char *ptr, int len)
   if (lookup_minimal_symbol("_NSNewStringFromCString", 0, 0).minsym)
     {
       function = find_function_in_inferior("_NSNewStringFromCString", NULL);
-      nsstringValue = call_function_by_hand(function,
-					    NULL, 1, &stringValue[2]);
+      nsstringValue = call_function_by_hand(function, NULL, stringValue[2]);
     }
   else if (lookup_minimal_symbol("istr", 0, 0).minsym)
     {
       function = find_function_in_inferior("istr", NULL);
-      nsstringValue = call_function_by_hand(function, NULL, 1, &stringValue[2]);
+      nsstringValue = call_function_by_hand(function, NULL, stringValue[2]);
     }
   else if (lookup_minimal_symbol("+[NSString stringWithCString:]", 0, 0).minsym)
     {
@@ -199,7 +198,7 @@ value_nsstring (struct gdbarch *gdbarch, char *ptr, int len)
 	(type, lookup_objc_class (gdbarch, "NSString"));
       stringValue[1] = value_from_longest 
 	(type, lookup_child_selector (gdbarch, "stringWithCString:"));
-      nsstringValue = call_function_by_hand(function, NULL, 3, &stringValue[0]);
+      nsstringValue = call_function_by_hand(function, NULL, stringValue);
     }
   else
     error (_("NSString: internal error -- no way to create new NSString"));
@@ -1189,7 +1188,7 @@ print_object_command (const char *args, int from_tty)
   if (function == NULL)
     error (_("Unable to locate _NSPrintForDebugger in child process"));
 
-  description = call_function_by_hand (function, NULL, 1, &object);
+  description = call_function_by_hand (function, NULL, object);
 
   string_addr = value_as_long (description);
   if (string_addr == 0)