[gcc r12-1611] [Ada] GNAT.Compiler_Version and LTO

[gcc r12-1611] [Ada] GNAT.Compiler_Version and LTO

[Pierre-Marie de Rodat]

https://gcc.gnu.org/g:4153c7547146cbd775385569bfdaa6cb3fe19007

commit r12-1611-g4153c7547146cbd775385569bfdaa6cb3fe19007
Author: Arnaud Charlet <charlet@adacore.com>
Date:   Fri Mar 12 07:57:03 2021 -0500

    [Ada] GNAT.Compiler_Version and LTO
    
    gcc/ada/
    
            * bindgen.adb (Gen_Output_File_Ada): Generate a new constant
            GNAT_Version_Address.
            * libgnat/g-comver.adb (GNAT_Version_Address): New;
            (GNAT_Version): Use GNAT_Version_Address to disable LTO warning.

Diff:
---
 gcc/ada/bindgen.adb          |  6 +++++-
 gcc/ada/libgnat/g-comver.adb | 11 ++++++++++-
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/gcc/ada/bindgen.adb b/gcc/ada/bindgen.adb
index 303bcdea344..0014f6a46da 100644
--- a/gcc/ada/bindgen.adb
+++ b/gcc/ada/bindgen.adb
@@ -2388,7 +2388,11 @@ package body Bindgen is
                                       Gnat_Version_String &
                                       """ & ASCII.NUL;");
             WBI ("   pragma Export (C, GNAT_Version, ""__gnat_version"");");
-
+            WBI ("");
+            WBI ("   GNAT_Version_Address : constant System.Address := " &
+                 "GNAT_Version'Address;");
+            WBI ("   pragma Export (C, GNAT_Version_Address, " &
+                 """__gnat_version_address"");");
             WBI ("");
             Set_String ("   Ada_Main_Program_Name : constant String := """);
             Get_Name_String (Units.Table (First_Unit_Entry).Uname);
diff --git a/gcc/ada/libgnat/g-comver.adb b/gcc/ada/libgnat/g-comver.adb
index e2aef3e6399..575caac5095 100644
--- a/gcc/ada/libgnat/g-comver.adb
+++ b/gcc/ada/libgnat/g-comver.adb
@@ -33,6 +33,8 @@
 --  GNAT compiler used to compile the program. It relies on the generated
 --  constant in the binder generated package that records this information.
 
+with System;
+
 package body GNAT.Compiler_Version is
 
    Ver_Len_Max : constant := 256;
@@ -43,8 +45,15 @@ package body GNAT.Compiler_Version is
    --  This is logically a reference to Gnatvsn.Ver_Prefix but we cannot
    --  import this directly since run-time units cannot WITH compiler units.
 
+   GNAT_Version_Address : constant System.Address;
+   pragma Import (C, GNAT_Version_Address, "__gnat_version_address");
+
    GNAT_Version : constant String (1 .. Ver_Len_Max + Ver_Prefix'Length);
-   pragma Import (C, GNAT_Version, "__gnat_version");
+   pragma Import (Ada, GNAT_Version);
+   for GNAT_Version'Address use GNAT_Version_Address;
+   --  Use a level of indirection via __gnat_version_address to avoid LTO
+   --  type mismtch warnings between two string objects of potentially
+   --  different size.
 
    -------------
    -- Version --