[gcc r12-2106] [Ada] Simplify handling of Generate_Code flag for compilation units

[gcc r12-2106] [Ada] Simplify handling of Generate_Code flag for compilation units

[Pierre-Marie de Rodat]

https://gcc.gnu.org/g:05435609367c0ae1398ac1b4becfae06d217552c

commit r12-2106-g05435609367c0ae1398ac1b4becfae06d217552c
Author: Piotr Trojanek <trojanek@adacore.com>
Date:   Tue May 18 14:54:24 2021 +0200

    [Ada] Simplify handling of Generate_Code flag for compilation units
    
    gcc/ada/
    
            * gnat1drv.adb (Gnat1drv): Remove flagging of main unit and its
            corresponding spec as requiring code generation; now the flags
            are set much earlier.
            * lib-load.adb (Load_Main_Source): Set Generate_Code flag on the
            main unit source.
            (Make_Instance_Unit): Copy Generate_Code flag from the main unit
            to instance units.
            * lib-writ.adb (Write_ALI): Remove redundant condition;
            Generate_Code flag is always set for the main unit.
            * par-load.adb (Load): Set Generate_Code flag on the main unit's
            corresponding spec, if any.

Diff:
---
 gcc/ada/gnat1drv.adb | 23 -----------------------
 gcc/ada/lib-load.adb | 11 +++++------
 gcc/ada/lib-writ.adb |  2 +-
 gcc/ada/par-load.adb |  6 ++++++
 4 files changed, 12 insertions(+), 30 deletions(-)

diff --git a/gcc/ada/gnat1drv.adb b/gcc/ada/gnat1drv.adb
index 22c93113709..6f65d7480f2 100644
--- a/gcc/ada/gnat1drv.adb
+++ b/gcc/ada/gnat1drv.adb
@@ -1287,29 +1287,6 @@ begin
          Exit_Program (E_Errors);
       end if;
 
-      --  Set Generate_Code on main unit and its spec. We do this even if are
-      --  not generating code, since Lib-Writ uses this to determine which
-      --  units get written in the ali file.
-
-      Set_Generate_Code (Main_Unit);
-
-      --  If we have a corresponding spec, and it comes from source or it is
-      --  not a generated spec for a child subprogram body, then we need object
-      --  code for the spec unit as well.
-
-      if Nkind (Unit (Main_Unit_Node)) in N_Unit_Body
-        and then not Acts_As_Spec (Main_Unit_Node)
-      then
-         if Nkind (Unit (Main_Unit_Node)) = N_Subprogram_Body
-           and then not Comes_From_Source (Library_Unit (Main_Unit_Node))
-         then
-            null;
-         else
-            Set_Generate_Code
-              (Get_Cunit_Unit_Number (Library_Unit (Main_Unit_Node)));
-         end if;
-      end if;
-
       --  Case of no code required to be generated, exit indicating no error
 
       if Original_Operating_Mode = Check_Syntax then
diff --git a/gcc/ada/lib-load.adb b/gcc/ada/lib-load.adb
index 75b52e2240a..19afe268ea7 100644
--- a/gcc/ada/lib-load.adb
+++ b/gcc/ada/lib-load.adb
@@ -364,7 +364,7 @@ package body Lib.Load is
             Error_Location         => No_Location,
             Expected_Unit          => No_Unit_Name,
             Fatal_Error            => None,
-            Generate_Code          => False,
+            Generate_Code          => True,
             Has_RACW               => False,
             Filler                 => False,
             Ident_String           => Empty,
@@ -964,13 +964,12 @@ package body Lib.Load is
       Units.Increment_Last;
 
       if In_Main then
-         Units.Table (Units.Last)               := Units.Table (Main_Unit);
-         Units.Table (Units.Last).Cunit         := Library_Unit (N);
-         Units.Table (Units.Last).Generate_Code := True;
+         Units.Table (Units.Last)        := Units.Table (Main_Unit);
+         Units.Table (Units.Last).Cunit  := Library_Unit (N);
          Init_Unit_Name (Units.Last, Unit_Name (Main_Unit));
 
-         Units.Table (Main_Unit).Cunit          := N;
-         Units.Table (Main_Unit).Version        := Source_Checksum (Sind);
+         Units.Table (Main_Unit).Cunit   := N;
+         Units.Table (Main_Unit).Version := Source_Checksum (Sind);
          Init_Unit_Name (Main_Unit,
            Get_Body_Name
              (Unit_Name (Get_Cunit_Unit_Number (Library_Unit (N)))));
diff --git a/gcc/ada/lib-writ.adb b/gcc/ada/lib-writ.adb
index 3564f0f84a9..416052c943e 100644
--- a/gcc/ada/lib-writ.adb
+++ b/gcc/ada/lib-writ.adb
@@ -1253,7 +1253,7 @@ package body Lib.Writ is
       --  for which we have generated code
 
       for Unit in Units.First .. Last_Unit loop
-         if Units.Table (Unit).Generate_Code or else Unit = Main_Unit then
+         if Units.Table (Unit).Generate_Code then
             if not Has_No_Elaboration_Code (Cunit (Unit)) then
                Main_Restrictions.Violated (No_Elaboration_Code) := True;
                exit;
diff --git a/gcc/ada/par-load.adb b/gcc/ada/par-load.adb
index 39c445ea992..0773f36946f 100644
--- a/gcc/ada/par-load.adb
+++ b/gcc/ada/par-load.adb
@@ -265,6 +265,12 @@ begin
          --  and this is also where we generate the SCO's for this spec.
 
          if Cur_Unum = Main_Unit then
+
+            --  We generate code for the main unit body, so we need to generate
+            --  code for its spec too.
+
+            Set_Generate_Code (Unum, True);
+
             Main_Unit_Entity := Cunit_Entity (Unum);
 
             if Generate_SCO then