[COMMITTED 19/35] ada: Minor performance improvement for dynamically-allocated controlled objects

["Marc Poulhiès" <poulhies@adacore.com>]

From: Eric Botcazou <ebotcazou@adacore.com>

The values returned by Header_Alignment and Header_Size are known at compile
time and powers of two on almost all platforms, so inlining them by means of
an expression function improves the object code generated for alignment and
size calculations involving them.

gcc/ada/

	* libgnat/s-finpri.ads: Add use type clause for Storage_Offset.
	(Header_Alignment): Turn into an expression function.
	(Header_Size): Likewise.
	* libgnat/s-finpri.adb: Remove use type clause for Storage_Offset.
	(Header_Alignment): Delete.
	(Header_Size): Likewise.

Tested on x86_64-pc-linux-gnu, committed on master.

---
 gcc/ada/libgnat/s-finpri.adb | 20 --------------------
 gcc/ada/libgnat/s-finpri.ads |  8 ++++++--
 2 files changed, 6 insertions(+), 22 deletions(-)

diff --git a/gcc/ada/libgnat/s-finpri.adb b/gcc/ada/libgnat/s-finpri.adb
index 5bd8eeaea22..bd70e582de3 100644
--- a/gcc/ada/libgnat/s-finpri.adb
+++ b/gcc/ada/libgnat/s-finpri.adb
@@ -37,8 +37,6 @@ with System.Soft_Links;        use System.Soft_Links;
 
 package body System.Finalization_Primitives is
 
-   use type System.Storage_Elements.Storage_Offset;
-
    function To_Collection_Node_Ptr is
      new Ada.Unchecked_Conversion (Address, Collection_Node_Ptr);
 
@@ -389,24 +387,6 @@ package body System.Finalization_Primitives is
       end if;
    end Finalize_Object;
 
-   ----------------------
-   -- Header_Alignment --
-   ----------------------
-
-   function Header_Alignment return System.Storage_Elements.Storage_Count is
-   begin
-      return Collection_Node'Alignment;
-   end Header_Alignment;
-
-   -----------------
-   -- Header_Size --
-   -----------------
-
-   function Header_Size return System.Storage_Elements.Storage_Count is
-   begin
-      return Collection_Node'Object_Size / Storage_Unit;
-   end Header_Size;
-
    ----------------
    -- Initialize --
    ----------------
diff --git a/gcc/ada/libgnat/s-finpri.ads b/gcc/ada/libgnat/s-finpri.ads
index 468aa584958..b0b662ca39c 100644
--- a/gcc/ada/libgnat/s-finpri.ads
+++ b/gcc/ada/libgnat/s-finpri.ads
@@ -39,6 +39,8 @@ with System.Storage_Elements;
 
 package System.Finalization_Primitives with Preelaborate is
 
+   use type System.Storage_Elements.Storage_Offset;
+
    type Finalize_Address_Ptr is access procedure (Obj : System.Address);
    --  Values of this type denote finalization procedures associated with
    --  objects that have controlled parts. For convenience, such objects
@@ -168,10 +170,12 @@ package System.Finalization_Primitives with Preelaborate is
    --  Calls to the procedure with an object that has already been detached
    --  have no effects.
 
-   function Header_Alignment return System.Storage_Elements.Storage_Count;
+   function Header_Alignment return System.Storage_Elements.Storage_Count is
+     (Collection_Node'Alignment);
    --  Return the alignment of type Collection_Node as Storage_Count
 
-   function Header_Size return System.Storage_Elements.Storage_Count;
+   function Header_Size return System.Storage_Elements.Storage_Count is
+     (Collection_Node'Object_Size / Storage_Unit);
    --  Return the object size of type Collection_Node as Storage_Count
 
 private
-- 
2.43.2