[gcc r12-5670] [Ada] Create object file for ignored ghost compilation unit

[gcc r12-5670] [Ada] Create object file for ignored ghost compilation unit

[Pierre-Marie de Rodat]

https://gcc.gnu.org/g:8ba38e8c8b737df2734c06486a7fc39f4be78f43

commit r12-5670-g8ba38e8c8b737df2734c06486a7fc39f4be78f43
Author: Richard Kenner <kenner@adacore.com>
Date:   Sat Nov 13 08:33:29 2021 -0500

    [Ada] Create object file for ignored ghost compilation unit
    
    gcc/ada/
    
            * gnat1drv.adb (Gnat1drv): Force generation of object file if
            compilation unit is an ignored ghost.

Diff:
---
 gcc/ada/gnat1drv.adb | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/gcc/ada/gnat1drv.adb b/gcc/ada/gnat1drv.adb
index 55f9efa777b..12ec98b1e61 100644
--- a/gcc/ada/gnat1drv.adb
+++ b/gcc/ada/gnat1drv.adb
@@ -1415,18 +1415,19 @@ begin
 
       if Back_End_Mode = Skip then
 
-         --  An ignored Ghost unit is rewritten into a null statement because
-         --  it must not produce an ALI or object file. Do not emit any errors
-         --  related to code generation because the unit does not exist.
+         --  An ignored Ghost unit is rewritten into a null statement. Do
+         --  not emit any errors related to code generation because the
+         --  unit does not exist.
 
          if Is_Ignored_Ghost_Unit (Main_Unit_Node) then
 
             --  Exit the gnat driver with success, otherwise external builders
             --  such as gnatmake and gprbuild will treat the compilation of an
-            --  ignored Ghost unit as a failure. Note that this will produce
-            --  an empty object file for the unit.
+            --  ignored Ghost unit as a failure. Be sure we produce an empty
+            --  object file for the unit.
 
             Ecode := E_Success;
+            Back_End.Gen_Or_Update_Object_File;
 
          --  Otherwise the unit is missing a crucial piece that prevents code
          --  generation.