[COMMITTED 33/35] ada: Start the initialization of the tasking runtime earlier

["Marc Poulhiès" <poulhies@adacore.com>]

From: Eric Botcazou <ebotcazou@adacore.com>

This installs the tasking versions of the RTS_Lock manipulation routines
very early, before the elaboration of all the Ada units of the program,
including those of the runtime, because this elaboration may require the
initialization of RTS_Lock objects.

gcc/ada/

	* bindgen.adb (Gen_Adainit): Generate declaration and call to the
	imported procedure __gnat_tasking_runtime_initialize if need be.
	* libgnat/s-soflin.ads (Locking Soft-Links): Add commentary.
	* libgnarl/s-tasini.adb (Tasking_Runtime_Initialize): New procedure
	exported as __gnat_tasking_runtime_initialize.  Initialize RTS_Lock
	manipulation routines here instead of...
	(Init_RTS): ...here.

Tested on x86_64-pc-linux-gnu, committed on master.

---
 gcc/ada/bindgen.adb           | 18 ++++++++++++++++--
 gcc/ada/libgnarl/s-tasini.adb | 30 +++++++++++++++++++++---------
 gcc/ada/libgnat/s-soflin.ads  |  4 +++-
 3 files changed, 40 insertions(+), 12 deletions(-)

diff --git a/gcc/ada/bindgen.adb b/gcc/ada/bindgen.adb
index fc834e3a9b6..f15f96495df 100644
--- a/gcc/ada/bindgen.adb
+++ b/gcc/ada/bindgen.adb
@@ -819,8 +819,7 @@ package body Bindgen is
             WBI ("      pragma Import (C, XDR_Stream, ""__gl_xdr_stream"");");
          end if;
 
-         --  Import entry point for elaboration time signal handler
-         --  installation, and indication of if it's been called previously.
+         --  Import entry point for initialization of the runtime
 
          WBI ("");
          WBI ("      procedure Runtime_Initialize " &
@@ -828,6 +827,15 @@ package body Bindgen is
          WBI ("      pragma Import (C, Runtime_Initialize, " &
               """__gnat_runtime_initialize"");");
 
+         --  Import entry point for initialization of the tasking runtime
+
+         if With_GNARL then
+            WBI ("");
+            WBI ("      procedure Tasking_Runtime_Initialize;");
+            WBI ("      pragma Import (C, Tasking_Runtime_Initialize, " &
+                 """__gnat_tasking_runtime_initialize"");");
+         end if;
+
          --  Import handlers attach procedure for sequential elaboration policy
 
          if System_Interrupts_Used
@@ -1090,6 +1098,12 @@ package body Bindgen is
          --  Generate call to Runtime_Initialize
 
          WBI ("      Runtime_Initialize (1);");
+
+         --  Generate call to Tasking_Runtime_Initialize
+
+         if With_GNARL then
+            WBI ("      Tasking_Runtime_Initialize;");
+         end if;
       end if;
 
       --  Generate call to set Initialize_Scalar values if active
diff --git a/gcc/ada/libgnarl/s-tasini.adb b/gcc/ada/libgnarl/s-tasini.adb
index 22294145bed..794183f5356 100644
--- a/gcc/ada/libgnarl/s-tasini.adb
+++ b/gcc/ada/libgnarl/s-tasini.adb
@@ -102,10 +102,6 @@ package body System.Tasking.Initialization is
    procedure Release_RTS_Lock (Addr : Address);
    --  Release the RTS lock at Addr
 
-   ------------------------
-   --  Local Subprograms --
-   ------------------------
-
    ----------------------------
    -- Tasking Initialization --
    ----------------------------
@@ -116,6 +112,15 @@ package body System.Tasking.Initialization is
    --  of initializing global locks, and installing tasking versions of certain
    --  operations used by the compiler. Init_RTS is called during elaboration.
 
+   procedure Tasking_Runtime_Initialize;
+   pragma Export (Ada, Tasking_Runtime_Initialize,
+                  "__gnat_tasking_runtime_initialize");
+   --  This procedure starts the initialization of the GNARL. It installs the
+   --  tasking versions of the RTS_Lock manipulation routines. It is called
+   --  very early before the elaboration of all the Ada units of the program,
+   --  including those of the runtime, because this elaboration may require
+   --  the initialization of RTS_Lock objects.
+
    --------------------------
    -- Change_Base_Priority --
    --------------------------
@@ -414,11 +419,6 @@ package body System.Tasking.Initialization is
       SSL.Task_Name          := Task_Name'Access;
       SSL.Get_Current_Excep  := Get_Current_Excep'Access;
 
-      SSL.Initialize_RTS_Lock := Initialize_RTS_Lock'Access;
-      SSL.Finalize_RTS_Lock   := Finalize_RTS_Lock'Access;
-      SSL.Acquire_RTS_Lock    := Acquire_RTS_Lock'Access;
-      SSL.Release_RTS_Lock    := Release_RTS_Lock'Access;
-
       --  Initialize the tasking soft links (if not done yet) that are common
       --  to the full and the restricted run times.
 
@@ -430,6 +430,18 @@ package body System.Tasking.Initialization is
       Undefer_Abort (Environment_Task);
    end Init_RTS;
 
+   --------------------------------
+   -- Tasking_Runtime_Initialize --
+   --------------------------------
+
+   procedure Tasking_Runtime_Initialize is
+   begin
+      SSL.Initialize_RTS_Lock := Initialize_RTS_Lock'Access;
+      SSL.Finalize_RTS_Lock   := Finalize_RTS_Lock'Access;
+      SSL.Acquire_RTS_Lock    := Acquire_RTS_Lock'Access;
+      SSL.Release_RTS_Lock    := Release_RTS_Lock'Access;
+   end Tasking_Runtime_Initialize;
+
    ---------------------------
    -- Locked_Abort_To_Level--
    ---------------------------
diff --git a/gcc/ada/libgnat/s-soflin.ads b/gcc/ada/libgnat/s-soflin.ads
index e88268081d8..c2d947535d9 100644
--- a/gcc/ada/libgnat/s-soflin.ads
+++ b/gcc/ada/libgnat/s-soflin.ads
@@ -258,12 +258,14 @@ package System.Soft_Links is
    procedure Null_Set_Address (Addr : Address) is null;
 
    --  Soft-Links are used for procedures that manipulate locks to avoid
-   --  dragging the tasking run time when using access-to-controlled types.
+   --  dragging the tasking runtime when using access-to-controlled types.
 
    Initialize_RTS_Lock : Set_Address_Call := Null_Set_Address'Access;
    Finalize_RTS_Lock   : Set_Address_Call := Null_Set_Address'Access;
    Acquire_RTS_Lock    : Set_Address_Call := Null_Set_Address'Access;
    Release_RTS_Lock    : Set_Address_Call := Null_Set_Address'Access;
+   --  The initialization of these variables must be static because the value
+   --  needs to be overridden very early when the tasking runtime is dragged.
 
    --------------------------
    -- Master_Id Soft-Links --
-- 
2.43.2