[Ada] Forced elaboration order in Elaboration order v4.0

This patch refactors the forced elaboration order functionality,
reintegrates it in Binde, and impelements it in Bindo.

------------
-- Source --
------------

--  server.ads

package Server is
end Server;

--  client.ads

with Server;

package Client is
end Client;

--  main.adb

with Client;

procedure Main is begin null; end Main;

--  duplicate_1.txt

server (spec)
client (spec)
server (spec)

--  error_unit_1.txt

no such unit
client (spec)

--  error_unit_2.txt

no such unit
client (spec)

--  error_unit_3.txt

no such unit     --  comment
client (spec)

--  error_unit_4.txt

         no such unit     --  comment

client (spec)

--  error_unit_5.txt

no such unit (body)
client (spec)

--  error_unit_6.txt

    no such unit (body)
client (spec)

--  error_unit_7.txt

    no such unit (body)    --  comment
client (spec)

--  error_unit_8.txt

    no such unit (body)--  comment
client (spec)

--  error_unit_9.txt

    no such unit--  comment
client (spec)

--  no_unit_1.txt

--  no_unit_2.txt

--  no_unit_3.txt

      --  comment

--  no_unit_4.txt

--  no_unit_5.txt

--  no_unit_6.txt

       --  comment

--  no_unit_7.txt

--  no_unit_8.txt

    --  comment
--  comment

--  ok_unit_1.txt

server (spec)
client (spec)

--  ok_unit_2.txt

    server (spec)
client (spec)

--  ok_unit_3.txt

    server (spec)
client (spec)

--  ok_unit_4.txt

    server (spec)      --  comment
client (spec)

--  ok_unit_5.txt

server (spec)
client (spec)

--  ok_unit_6.txt

server (spec)
client (spec)    --  comment

--  ok_unit_7.txt

server (spec)
client (spec)    --  comment

--  ok_unit_8.txt

    --  comment
--  comment
    server (spec)

   --  comment
--  comment

client (spec)    --  comment

--  ok_unit_9.txt

server (spec)--  comment
client (spec)

----------------------------
-- Compilation and output --
----------------------------
$ gnatmake -q main.adb
$ gnatbind -fno_unit_1.txt main.ali
$ gnatbind -fno_unit_2.txt main.ali
$ gnatbind -fno_unit_3.txt main.ali
$ gnatbind -fno_unit_4.txt main.ali
$ gnatbind -fno_unit_5.txt main.ali
$ gnatbind -fno_unit_6.txt main.ali
$ gnatbind -fno_unit_7.txt main.ali
$ gnatbind -fno_unit_8.txt main.ali
$ gnatbind -ferror_unit_1.txt main.ali
$ gnatbind -ferror_unit_2.txt main.ali
$ gnatbind -ferror_unit_3.txt main.ali
$ gnatbind -ferror_unit_4.txt main.ali
$ gnatbind -ferror_unit_5.txt main.ali
$ gnatbind -ferror_unit_6.txt main.ali
$ gnatbind -ferror_unit_7.txt main.ali
$ gnatbind -ferror_unit_8.txt main.ali
$ gnatbind -ferror_unit_9.txt main.ali
$ gnatbind -fduplicate_1.txt main.ali
$ gnatbind -fok_unit_1.txt main.ali
$ gnatbind -fok_unit_2.txt main.ali
$ gnatbind -fok_unit_3.txt main.ali
$ gnatbind -fok_unit_4.txt main.ali
$ gnatbind -fok_unit_5.txt main.ali
$ gnatbind -fok_unit_6.txt main.ali
$ gnatbind -fok_unit_7.txt main.ali
$ gnatbind -fok_unit_8.txt main.ali
$ gnatbind -fok_unit_9.txt main.ali
"no such unit": not present; ignored
"no such unit": not present; ignored
"no such unit": not present; ignored
"no such unit": not present; ignored
"no such unit%b": not present; ignored
"no such unit%b": not present; ignored
"no such unit%b": not present; ignored
"no such unit%b": not present; ignored
"no such unit": not present; ignored
server (spec) <-- client (spec)
error: duplicate_1.txt:3: duplicate unit name "server (spec)" from line 1
server (spec) <-- client (spec)
server (spec) <-- client (spec)
server (spec) <-- client (spec)
server (spec) <-- client (spec)
server (spec) <-- client (spec)
server (spec) <-- client (spec)
server (spec) <-- client (spec)
server (spec) <-- client (spec)
server (spec) <-- client (spec)

2019-07-03  Hristian Kirtchev  <kirtchev@adacore.com>

gcc/ada/

	* binde.adb: Remove with clause for System.OS_Lib.
	(Force_Elab_Order): Refactor the majority of the code in Butil.
	Use the new forced units iterator to obtain unit names.
	* bindo-builders.adb: Add with and use clauses for Binderr,
	Butil, Opt, Output, Types, GNAT, and GNAT.Dynamic_HTables.  Add
	a hash table which maps units to line number in the forced
	elaboration order file.
	(Add_Unit): New routine.
	(Build_Library_Graph): Create forced edges between pairs of
	units listed in the forced elaboration order file.
	(Create_Forced_Edge, Create_Forced_Edges, Destroy_Line_Number,
	Duplicate_Unit_Error, Hash_Unit, Internal_Unit_Info,
	Is_Duplicate_Unit, Missing_Unit_Info): New routines.
	* bindo-graphs.adb (Is_Internal_Unit, Is_Predefined_Unit):
	Refactor some of the behavior to Bindo-Units.
	* bindo-graphs.ads: Enable the enumeration literal for forced
	edges.
	* bindo-units.adb, bindo-units.ads (Is_Internal_Unit,
	Is_Predefined_Unit): New routines.
	* butil.adb: Add with and use clauses for Opt, GNAT, and
	System.OS_Lib.  Add with clause for Unchecked_Deallocation.
	(Has_Next, Iterate_Forced_Units, Next, Parse_Next_Unit_Name,
	Read_Forced_Elab_Order_File): New routines.
	* butil.ads: Add with and use clauses for Types.  Add new
	iterator over the units listed in the forced elaboration order
	file.
	(Has_Next, Iterate_Forced_Units, Next): New routine.
	* namet.adb, namet.ads (Present): New routine.

From-SVN: r272987

gcc/ada/ChangeLog

+2019-07-03  Hristian Kirtchev  <kirtchev@adacore.com>
+
+	* binde.adb: Remove with clause for System.OS_Lib.
+	(Force_Elab_Order): Refactor the majority of the code in Butil.
+	Use the new forced units iterator to obtain unit names.
+	* bindo-builders.adb: Add with and use clauses for Binderr,
+	Butil, Opt, Output, Types, GNAT, and GNAT.Dynamic_HTables.  Add
+	a hash table which maps units to line number in the forced
+	elaboration order file.
+	(Add_Unit): New routine.
+	(Build_Library_Graph): Create forced edges between pairs of
+	units listed in the forced elaboration order file.
+	(Create_Forced_Edge, Create_Forced_Edges, Destroy_Line_Number,
+	Duplicate_Unit_Error, Hash_Unit, Internal_Unit_Info,
+	Is_Duplicate_Unit, Missing_Unit_Info): New routines.
+	* bindo-graphs.adb (Is_Internal_Unit, Is_Predefined_Unit):
+	Refactor some of the behavior to Bindo-Units.
+	* bindo-graphs.ads: Enable the enumeration literal for forced
+	edges.
+	* bindo-units.adb, bindo-units.ads (Is_Internal_Unit,
+	Is_Predefined_Unit): New routines.
+	* butil.adb: Add with and use clauses for Opt, GNAT, and
+	System.OS_Lib.  Add with clause for Unchecked_Deallocation.
+	(Has_Next, Iterate_Forced_Units, Next, Parse_Next_Unit_Name,
+	Read_Forced_Elab_Order_File): New routines.
+	* butil.ads: Add with and use clauses for Types.  Add new
+	iterator over the units listed in the forced elaboration order
+	file.
+	(Has_Next, Iterate_Forced_Units, Next): New routine.
+	* namet.adb, namet.ads (Present): New routine.
+
 2019-07-03  Bob Duff  <duff@adacore.com>
 
 	* sem_ch3.adb (Access_Definition): The code was creating a

gcc/ada/bindo-graphs.adb

@@ -2069,10 +2069,8 @@ package body Bindo.Graphs is
 
          pragma Assert (Present (U_Id));
 
-         U_Rec : Unit_Record renames ALI.Units.Table (U_Id);
-
       begin
-         return U_Rec.Internal;
+         return Is_Internal_Unit (U_Id);
       end Is_Internal_Unit;
 
       ------------------------
@@ -2090,10 +2088,8 @@ package body Bindo.Graphs is
 
          pragma Assert (Present (U_Id));
 
-         U_Rec : Unit_Record renames ALI.Units.Table (U_Id);
-
       begin
-         return U_Rec.Predefined;
+         return Is_Predefined_Unit (U_Id);
       end Is_Predefined_Unit;
 
       ---------------------------

gcc/ada/bindo-graphs.ads

@@ -573,7 +573,7 @@ package Bindo.Graphs is
          Elaborate_All_Edge,
          --  Successor withs Predecessor, and has pragma Elaborate_All for it
 
---       Forced_Edge,
+         Forced_Edge,
          --  Successor is forced to with Predecessor by virtue of an existing
          --  elaboration order provided in a file.
 

gcc/ada/bindo-units.adb

@@ -233,6 +233,32 @@ package body Bindo.Units is
       return U_Rec.Dynamic_Elab;
    end Is_Dynamically_Elaborated;
 
+   ----------------------
+   -- Is_Internal_Unit --
+   ----------------------
+
+   function Is_Internal_Unit (U_Id : Unit_Id) return Boolean is
+      pragma Assert (Present (U_Id));
+
+      U_Rec : Unit_Record renames ALI.Units.Table (U_Id);
+
+   begin
+      return U_Rec.Internal;
+   end Is_Internal_Unit;
+
+   ------------------------
+   -- Is_Predefined_Unit --
+   ------------------------
+
+   function Is_Predefined_Unit (U_Id : Unit_Id) return Boolean is
+      pragma Assert (Present (U_Id));
+
+      U_Rec : Unit_Record renames ALI.Units.Table (U_Id);
+
+   begin
+      return U_Rec.Predefined;
+   end Is_Predefined_Unit;
+
    ---------------------------------
    -- Is_Stand_Alone_Library_Unit --
    ---------------------------------

gcc/ada/bindo-units.ads

@@ -78,6 +78,14 @@ package Bindo.Units is
    --  Determine whether unit U_Id was compiled using the dynamic elaboration
    --  model.
 
+   function Is_Internal_Unit (U_Id : Unit_Id) return Boolean;
+   pragma Inline (Is_Internal_Unit);
+   --  Determine whether unit U_Id is internal
+
+   function Is_Predefined_Unit (U_Id : Unit_Id) return Boolean;
+   pragma Inline (Is_Predefined_Unit);
+   --  Determine whether unit U_Id is predefined
+
    function Name (U_Id : Unit_Id) return Unit_Name_Type;
    pragma Inline (Name);
    --  Obtain the name of unit U_Id

gcc/ada/butil.ads

@@ -23,12 +23,13 @@
 --                                                                          --
 ------------------------------------------------------------------------------
 
+--  This package contains utility routines for the binder
+
 with Namet; use Namet;
+with Types; use Types;
 
 package Butil is
 
---  This package contains utility routines for the binder
-
    function Is_Predefined_Unit return Boolean;
    --  Given a unit name stored in Name_Buffer with length in Name_Len,
    --  returns True if this is the name of a predefined unit or a child of
@@ -51,4 +52,52 @@ package Butil is
    --  Output unit name with (body) or (spec) after as required. On return
    --  Name_Len is set to the number of characters which were output.
 
+   ---------------
+   -- Iterators --
+   ---------------
+
+   --  The following type represents an iterator over all units that are
+   --  specified in the forced-elaboration-order file supplied by the binder
+   --  via switch -f.
+
+   type Forced_Units_Iterator is private;
+
+   function Has_Next (Iter : Forced_Units_Iterator) return Boolean;
+   pragma Inline (Has_Next);
+   --  Determine whether iterator Iter has more units to examine
+
+   function Iterate_Forced_Units return Forced_Units_Iterator;
+   pragma Inline (Iterate_Forced_Units);
+   --  Obtain an iterator over all units in the forced-elaboration-order file
+
+   procedure Next
+     (Iter      : in out Forced_Units_Iterator;
+      Unit_Name : out Unit_Name_Type;
+      Unit_Line : out Logical_Line_Number);
+   pragma Inline (Next);
+   --  Return the current unit referenced by iterator Iter along with the
+   --  line number it appears on, and advance to the next available unit.
+
+private
+   First_Line_Number : constant Logical_Line_Number := No_Line_Number + 1;
+
+   type Forced_Units_Iterator is record
+      Order : String_Ptr := null;
+      --  A reference to the contents of the forced-elaboration-order file,
+      --  read in as a string.
+
+      Order_Index : Positive := 1;
+      --  Index into the order string
+
+      Order_Line : Logical_Line_Number := First_Line_Number;
+      --  Logical line number within the order string
+
+      Unit_Line : Logical_Line_Number := No_Line_Number;
+      --  The logical line number of the current unit name within the order
+      --  string.
+
+      Unit_Name : Unit_Name_Type := No_Unit_Name;
+      --  The current unit name parsed from the order string
+   end record;
+
 end Butil;

gcc/ada/namet.adb

@@ -1515,6 +1515,15 @@ package body Namet is
       return Nam /= No_Name;
    end Present;
 
+   -------------
+   -- Present --
+   -------------
+
+   function Present (Nam : Unit_Name_Type) return Boolean is
+   begin
+      return Nam /= No_Unit_Name;
+   end Present;
+
    ------------------
    -- Reinitialize --
    ------------------

gcc/ada/namet.ads

@@ -658,6 +658,10 @@ package Namet is
    No_Unit_Name : constant Unit_Name_Type := Unit_Name_Type (No_Name);
    --  Constant used to indicate no file name present
 
+   function Present (Nam : Unit_Name_Type) return Boolean;
+   pragma Inline (Present);
+   --  Determine whether unit name Nam exists
+
    Error_Unit_Name : constant Unit_Name_Type := Unit_Name_Type (Error_Name);
    --  The special Unit_Name_Type value Error_Unit_Name is used to indicate
    --  a unit name where some previous processing has found an error.