Add comments.

4 files changed, 15 insertions, 4 deletions

diff --git a/src/ghdldrv/ghdldrv.adb b/src/ghdldrv/ghdldrv.adb
index 6ffeef8a3..7e418d6b2 100644
--- a/src/ghdldrv/ghdldrv.adb
+++ b/src/ghdldrv/ghdldrv.adb
@@ -1470,6 +1470,8 @@ package body Ghdldrv is
             Unit := Get_First_Design_Unit (File);
             while Unit /= Null_Iir loop
                Lib_Unit := Get_Library_Unit (Unit);
+               --  Check if the unit is outdated (except for default
+               --  configurations).
                if not (Get_Kind (Lib_Unit) = Iir_Kind_Configuration_Declaration
                        and then Get_Identifier (Lib_Unit) = Null_Identifier)
                then
diff --git a/src/ghdldrv/ghdllocal.adb b/src/ghdldrv/ghdllocal.adb
index be4587d63..ede9526f0 100644
--- a/src/ghdldrv/ghdllocal.adb
+++ b/src/ghdldrv/ghdllocal.adb
@@ -1207,6 +1207,7 @@ package body Ghdllocal is
       Work_Library := Old_Work;
    end Load_All_Libraries_And_Files;
 
+   --  Check the Elab_Flag is not set on design units of LIB.
    procedure Check_No_Elab_Flag (Lib : Iir_Library_Declaration)
    is
       File : Iir_Design_File;
@@ -1271,6 +1272,7 @@ package body Ghdllocal is
       end if;
 
       if True then
+         --  Load the world.
          Load_All_Libraries_And_Files;
       else
          --  Re-parse modified files in order configure could find all design
@@ -1313,11 +1315,11 @@ package body Ghdllocal is
 
       Top := Configure (Primary_Id, Secondary_Id);
       if Top = Null_Iir then
-         --Error ("cannot find primary unit " & Prim.all);
+         --  Error during configuration (primary unit not found).
          raise Option_Error;
       end if;
 
-      --  Add unused design units.
+      --  Add unused design units (and their dependencies).
       declare
          N : Natural;
       begin
@@ -1339,7 +1341,8 @@ package body Ghdllocal is
          end loop;
       end;
 
-      --  Clear elab flag on design files.
+      --  Clear elab flag on design files (as it is used by below by
+      --  Build_Dependence_List).
       for I in reverse Design_Units.First .. Design_Units.Last loop
          Unit := Design_Units.Table (I);
          File := Get_Design_File (Unit);
diff --git a/src/vhdl/configuration.adb b/src/vhdl/configuration.adb
index f570b692e..93d4b0072 100644
--- a/src/vhdl/configuration.adb
+++ b/src/vhdl/configuration.adb
@@ -43,8 +43,10 @@ package body Configuration is
       Prev_File_Dependence : Iir_List;
    begin
       if Flag_Build_File_Dependence then
+         --  The current file depends on unit.
          File := Get_Design_File (Unit);
          if Current_File_Dependence /= Null_Iir_List then
+            --  (There is no dependency for default configuration).
             Add_Element (Current_File_Dependence, File);
          end if;
       end if;
@@ -69,6 +71,7 @@ package body Configuration is
       Lib_Unit := Get_Library_Unit (Unit);
 
       if Flag_Build_File_Dependence then
+         --  Switch current_file_dependence to the design file of Unit.
          Prev_File_Dependence := Current_File_Dependence;
 
          if Get_Kind (Lib_Unit) = Iir_Kind_Configuration_Declaration
@@ -505,7 +508,9 @@ package body Configuration is
    --  For each element of the list:
    --  add direct dependences (packages, entity, arch) if not in the list
    --  for architectures and configuration: find instantiations and add
-   --  corresponding configurations
+   --  corresponding configurations.
+   --
+   --  Return the configuration declaration for the design.
    function Configure (Primary_Id : Name_Id; Secondary_Id : Name_Id)
      return Iir
    is
diff --git a/src/vhdl/configuration.ads b/src/vhdl/configuration.ads
index 0a19a23c2..e02a2cdfb 100644
--- a/src/vhdl/configuration.ads
+++ b/src/vhdl/configuration.ads
@@ -45,6 +45,7 @@ package Configuration is
    --  If set, all design units (even package bodies) are loaded.
    Flag_Load_All_Design_Units : Boolean := True;
 
+   --  If set, compute the File_Dependence_List of design files.
    Flag_Build_File_Dependence : Boolean := False;
 
    --  Check if ENTITY can be at the top of a hierarchy, ie: