+2014-07-17 Robert Dewar <dewar@adacore.com>
+
+ * bindgen.adb (Gen_Elab_Calls): Skip reference to elab
+ entity if none exists (Gen_Elab_Calls): Complain if clash with
+ No_Multiple_Elaboration.
+ * s-rident.ads, restrict.ads: Add restriction No_Multiple_Elaboration.
+ * sem_util.adb (Build_Elaboration_Entity): Skip building entity
+ if not needed.
+ * gnat_rm.texi: Document restriction No_Multiple_Elaboration.
+ * sem_ch4.adb: Minor comment updates.
+
2014-07-17 Ed Schonberg <schonberg@adacore.com>
* exp_ch9.adb (Buid_Protected_Subprogram_Call): Preserve type
-- --
-- B o d y --
-- --
--- Copyright (C) 1992-2013, Free Software Foundation, Inc. --
+-- Copyright (C) 1992-2014, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
Check_Elab_Flag : Boolean;
begin
+ -- Loop through elaboration order entries
+
for E in Elab_Order.First .. Elab_Order.Last loop
declare
Unum : constant Unit_Id := Elab_Order.Table (E);
-- Case of no elaboration code
- -- In CodePeer mode, we special case subprogram bodies which
- -- are handled in the 'else' part below, and lead to a call to
- -- <subp>'Elab_Subp_Body.
-
elsif U.No_Elab
+
+ -- In CodePeer mode, we special case subprogram bodies which
+ -- are handled in the 'else' part below, and lead to a call
+ -- to <subp>'Elab_Subp_Body.
+
and then (not CodePeer_Mode
+
+ -- Test for spec
+
or else U.Utype = Is_Spec
or else U.Utype = Is_Spec_Only
or else U.Unit_Kind /= 's')
then
-
-- In the case of a body with a separate spec, where the
-- separate spec has an elaboration entity defined, this is
- -- where we increment the elaboration entity.
+ -- where we increment the elaboration entity if one exists
if U.Utype = Is_Body
and then Units.Table (Unum_Spec).Set_Elab_Entity
-- a spec with a body, the elaboration entity is initialized
-- here. This is done because it's the only way to accomplish
-- initialization of such entities, as there is no mechanism
- -- provided for initializing global variables at load time on
- -- AAMP.
+ -- for load time global variable initialization on AAMP.
elsif AAMP_On_Target
and then U.Utype = Is_Spec
-- a spec with a body, the elaboration entity is initialized
-- here. This is done because it's the only way to accomplish
-- initialization of such entities, as there is no mechanism
- -- provided for initializing global variables at load time on
- -- AAMP.
+ -- for load time global variable initialization on AAMP.
if AAMP_On_Target
and then U.Utype = Is_Spec
Write_Statement_Buffer;
end if;
+ -- Check incompatibilities with No_Multiple_Elaboration
+
+ if not CodePeer_Mode
+ and then Cumulative_Restrictions.Set (No_Multiple_Elaboration)
+ then
+ -- Force_Checking_Of_Elaboration_Flags (-F) not allowed
+
+ if Force_Checking_Of_Elaboration_Flags then
+ Osint.Fail
+ ("-F (force elaboration checks) switch not allowed "
+ & "with restriction No_Multiple_Elaboration active");
+
+ -- Interfacing of libraries not allowed
+
+ elsif Interface_Library_Unit then
+ Osint.Fail
+ ("binding of interfaced libraries not allowed "
+ & "with restriction No_Multiple_Elaboration active");
+
+ -- Non-Ada main program not allowed
+
+ elsif not Bind_Main_Program then
+ Osint.Fail
+ ("non-Ada main program not allowed "
+ & "with restriction No_Multiple_Elaboration active");
+ end if;
+ end if;
+
+ -- OK, see if we need to test elaboration flag
+
Check_Elab_Flag :=
- not CodePeer_Mode
+ Units.Table (Unum_Spec).Set_Elab_Entity
+ and then not CodePeer_Mode
and then (Force_Checking_Of_Elaboration_Flags
or Interface_Library_Unit
or not Bind_Main_Program);
if U.Utype /= Is_Spec
and then not CodePeer_Mode
+ and then Units.Table (Unum_Spec).Set_Elab_Entity
then
Set_String (" E");
Set_Unit_Number (Unum_Spec);
+
\input texinfo @c -*-texinfo-*-
@c %**start of header
* No_Local_Protected_Objects::
* No_Local_Timing_Events::
* No_Long_Long_Integers::
+* No_Multiple_Elaboration::
* No_Nested_Finalization::
* No_Protected_Type_Allocators::
* No_Protected_Types::
* No_Local_Protected_Objects::
* No_Local_Timing_Events::
* No_Long_Long_Integers::
+* No_Multiple_Elaboration::
* No_Nested_Finalization::
* No_Protected_Type_Allocators::
* No_Protected_Types::
implicit base type is Long_Long_Integer, and modular types whose size exceeds
Long_Integer'Size.
+@node No_Multiple_Elaboration
+@unnumberedsubsec No_Multiple_Elaboration
+@findex No_Multiple_Elaboration
+[GNAT] Normally each package contains a 16-bit counter used to check for access
+before elaboration, and to control multiple elaboration attempts.
+This counter is eliminated for units compiled with the static model
+of elaboration if restriction @code{No_Elaboration_Code}
+is active but because of
+the need to check for multiple elaboration in the general case, these
+counters cannot be eliminated if elaboration code may be present. The
+restriction @code{No_Multiple_Elaboration}
+allows suppression of these counters
+in static elaboration units even if they do have elaboration code. If this
+restriction is used, then the situations in which multiple elaboration is
+possible, including non-Ada main programs, and Stand Alone libraries, are not
+permitted, and will be diagnosed by the binder.
+
@node No_Nested_Finalization
@unnumberedsubsec No_Nested_Finalization
@findex No_Nested_Finalization
No_Initialize_Scalars => True,
No_Local_Protected_Objects => True,
No_Long_Long_Integers => True,
+ No_Multiple_Elaboration => True,
No_Protected_Type_Allocators => True,
No_Relative_Delay => True,
No_Requeue_Statements => True,
No_Local_Timing_Events, -- (RM D.7(10.2/2))
No_Local_Protected_Objects, -- Ada 2012 (D.7(10/1.3))
No_Long_Long_Integers, -- GNAT
+ No_Multiple_Elaboration, -- GNAT
No_Nested_Finalization, -- (RM D.7(4))
No_Protected_Type_Allocators, -- Ada 2012 (D.7 (10.3/2))
No_Protected_Types, -- (RM H.4(5))
-- In accordance with H.4(7), the No_Allocators restriction only applies
-- to user-written allocators. The same consideration applies to the
- -- No_Allocators_Before_Elaboration restriction.
+ -- No_Standard_Allocators_Before_Elaboration restriction.
if Comes_From_Source (N) then
Check_Restriction (No_Allocators, N);
and then List_Containing (C) = Statements (P)
then
-- Check for allocator within task body, this is a definite
- -- violation of No_Allocators_After_Elaboration we can detect.
+ -- violation of No_Allocators_After_Elaboration we can detect
+ -- at compile time.
if Nkind (Original_Node (Parent (P))) = N_Task_Body then
Check_Restriction
-- Start of processing for Build_Elaboration_Entity
begin
- -- Ignore if already constructed
+ -- Ignore call if already constructed
if Present (Elaboration_Entity (Spec_Id)) then
return;
- end if;
-- Ignore in ASIS mode, elaboration entity is not in source and plays
-- no role in analysis.
- if ASIS_Mode then
+ elsif ASIS_Mode then
+ return;
+
+ -- See if we need elaboration entity. We always need it for the dynamic
+ -- elaboration model, since it is needed to properly generate the PE
+ -- exception for access before elaboration.
+
+ elsif Dynamic_Elaboration_Checks then
+ null;
+
+ -- For the static model, we don't need the elaboration counter if this
+ -- unit is sure to have no elaboration code, since that means there
+ -- is no elaboration unit to be called. Note that we can't just decide
+ -- after the fact by looking to see whether there was elaboration code,
+ -- because that's too late to make this decision.
+
+ elsif Restriction_Active (No_Elaboration_Code) then
+ return;
+
+ -- Similarly, for the static model, we can skip the elaboration counter
+ -- if we have the No_Multiple_Elaboration restriction, since for the
+ -- static model, that's the only purpose of the counter (to avoid
+ -- multiple elaboration).
+
+ elsif Restriction_Active (No_Multiple_Elaboration) then
return;
end if;
+ -- Here we need the elaboration entity
+
-- Construct name of elaboration entity as xxx_E, where xxx is the unit
-- name with dots replaced by double underscore. We have to manually
-- construct this name, since it will be elaborated in the outer scope,
Disc : Entity_Id)
is
Loc : constant Source_Ptr := Sloc (Expr);
- begin
+ begin
-- An entity of a type with a reference aspect is overloaded with
-- both interpretations: with and without the dereference. Now that
-- the dereference is made explicit, set the type of the node properly,
projects / thirdparty / gcc.git / commitdiff
