Add a pass_by_reference flag to function_arg_info

This patch adds a flag that tells targets whether an argument
has been converted to pass-by-reference form.  This replaces
assign_parm_data_one::passed_pointer in function.c.

The flag is set automatically for places that call
apply_pass_by_reference_rules.  Places that apply
pass-by-reference manually need to set it themselves.

(After previous changes, no targets apply pass-by-reference
manually.  They all go through apply_pass_by_reference_rules.)

2019-08-20  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* calls.h (function_arg_info): Add a pass_by_reference field,
	defaulting to false.
	* calls.c (apply_pass_by_reference_rules): Set pass_by_reference
	when applying pass-by-reference semantics.
	(initialize_argument_information): Likewise.
	(emit_library_call_value_1): Likewise.
	* function.c (assign_parm_data_one): Remove passed_pointer field.
	(assign_parm_find_data_types): Don't set it.
	(assign_parm_find_stack_rtl, assign_parm_adjust_stack_rtl)
	(assign_parm_setup_reg, assign_parms, gimplify_parameters): Use
	arg.pass_by_reference instead of passed_pointer.

From-SVN: r274707

1 files changed, 12 insertions, 4 deletions

diff --git a/gcc/calls.h b/gcc/calls.h
index 01ab3905a3a..a782a7d3695 100644
--- a/gcc/calls.h
+++ b/gcc/calls.h
@@ -34,21 +34,25 @@ along with GCC; see the file COPYING3.  If not see
 class function_arg_info
 {
 public:
-  function_arg_info () : type (NULL_TREE), mode (VOIDmode), named (false) {}
+  function_arg_info ()
+    : type (NULL_TREE), mode (VOIDmode), named (false),
+      pass_by_reference (false)
+  {}
 
   /* Initialize an argument of mode MODE, either before or after promotion.  */
   function_arg_info (machine_mode mode, bool named)
-    : type (NULL_TREE), mode (mode), named (named)
+    : type (NULL_TREE), mode (mode), named (named), pass_by_reference (false)
   {}
 
   /* Initialize an unpromoted argument of type TYPE.  */
   function_arg_info (tree type, bool named)
-    : type (type), mode (TYPE_MODE (type)), named (named)
+    : type (type), mode (TYPE_MODE (type)), named (named),
+      pass_by_reference (false)
   {}
 
   /* Initialize an argument with explicit properties.  */
   function_arg_info (tree type, machine_mode mode, bool named)
-    : type (type), mode (mode), named (named)
+    : type (type), mode (mode), named (named), pass_by_reference (false)
   {}
 
   /* Return true if the gimple-level type is an aggregate.  */
@@ -100,6 +104,10 @@ public:
      treated as an unnamed variadic argument (i.e. one passed through
      "...").  See also TARGET_STRICT_ARGUMENT_NAMING.  */
   unsigned int named : 1;
+
+  /* True if we have decided to pass the argument by reference, in which case
+     the function_arg_info describes a pointer to the original argument.  */
+  unsigned int pass_by_reference : 1;
 };
 
 extern int flags_from_decl_or_type (const_tree);