[gcc r12-6599] ada: Fix up handling of ghost units [PR104027]

[gcc r12-6599] ada: Fix up handling of ghost units [PR104027]

[Jakub Jelinek]

https://gcc.gnu.org/g:952b7dbb418198f86d7829aaf9d7f9fc7714a8b3

commit r12-6599-g952b7dbb418198f86d7829aaf9d7f9fc7714a8b3
Author: Andrew Pinski <apinski@marvell.com>
Date:   Fri Jan 14 23:58:38 2022 +0100

    ada: Fix up handling of ghost units [PR104027]
    
    As reported, libgnat-12.so gets PT_GNU_STACK RWE, which means it doesn't
    work in some SELinux configurations.
    This is caused by the a-nbnbig.o file, which is a ghost unit and since
    r12-5670 the FE emits an object file for it, but exits before compile_file
    has a chance to finalize it e.g. with targetm.asm_out.file_end ()
    that emits the .note.GNU-stack section on various linux targets.
    
    Fixed by not existing but instead returning early to the caller.
    
    2022-01-14  Andrew Pinski  <apinski@marvell.com>
    
            PR ada/104027
            * gnat1drv.adb (Gnat1drv): After Back_End.Gen_Or_Update_Object_File
            goto End_Of_Program.

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

diff --git a/gcc/ada/gnat1drv.adb b/gcc/ada/gnat1drv.adb
index 25c58238dca..f50feb2905d 100644
--- a/gcc/ada/gnat1drv.adb
+++ b/gcc/ada/gnat1drv.adb
@@ -1429,6 +1429,11 @@ begin
             Ecode := E_Success;
             Back_End.Gen_Or_Update_Object_File;
 
+            --  Use a goto instead of calling Exit_Program so that finalization
+            --  occurs normally.
+
+            goto End_Of_Program;
+
          --  Otherwise the unit is missing a crucial piece that prevents code
          --  generation.