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-- --
-- --
-- E X P A N D E R --
-- --
-- B o d y --
-- --
-- Copyright (C) 1992-2018, 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- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING3. If not, go to --
-- for a complete copy of the license. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
with Atree; use Atree;
with Debug; use Debug;
with Debug_A; use Debug_A;
with Exp_Aggr; use Exp_Aggr;
with Exp_SPARK; use Exp_SPARK;
with Exp_Attr; use Exp_Attr;
with Exp_Ch2; use Exp_Ch2;
with Exp_Ch3; use Exp_Ch3;
with Exp_Ch4; use Exp_Ch4;
with Exp_Ch5; use Exp_Ch5;
with Exp_Ch6; use Exp_Ch6;
with Exp_Ch7; use Exp_Ch7;
with Exp_Ch8; use Exp_Ch8;
with Exp_Ch9; use Exp_Ch9;
with Exp_Ch11; use Exp_Ch11;
with Exp_Ch12; use Exp_Ch12;
with Exp_Ch13; use Exp_Ch13;
with Exp_Prag; use Exp_Prag;
with Ghost; use Ghost;
with Opt; use Opt;
with Rtsfind; use Rtsfind;
with Sem; use Sem;
with Sem_Ch8; use Sem_Ch8;
with Sem_Util; use Sem_Util;
with Sinfo; use Sinfo;
with Table;
package body Expander is
-- Local Data --
-- The following table is used to save values of the Expander_Active flag
-- when they are saved by Expander_Mode_Save_And_Set. We use an extendible
-- table (which is a bit of overkill) because it is easier than figuring
-- out a maximum value or bothering with range checks.
package Expander_Flags is new Table.Table (
Table_Component_Type => Boolean,
Table_Index_Type => Int,
Table_Low_Bound => 0,
Table_Initial => 32,
Table_Increment => 200,
Table_Name => "Expander_Flags");
Abort_Bug_Box_Error : exception;
-- Arbitrary exception to raise for implementation of -gnatd.B. See "when
-- N_Abort_Statement" below. See also debug.adb.
-- Expand --
-- WARNING: This routine manages Ghost regions. Return statements must be
-- replaced by gotos which jump to the end of the routine and restore the
-- Ghost mode.
procedure Expand (N : Node_Id) is
Saved_GM : constant Ghost_Mode_Type := Ghost_Mode;
-- Save the Ghost mode to restore on exit
-- If we were analyzing a default expression (or other spec expression)
-- the Full_Analysis flag must be off. If we are in expansion mode then
-- we must be performing a full analysis. If we are analyzing a generic
-- then Expansion must be off.
pragma Assert
(not (Full_Analysis and then In_Spec_Expression)
and then (Full_Analysis or else not Expander_Active)
and then not (Inside_A_Generic and then Expander_Active));
-- Establish the Ghost mode of the context to ensure that any generated
-- nodes during expansion are marked as Ghost.
Set_Ghost_Mode (N);
-- The GNATprove_Mode flag indicates that a light expansion for formal
-- verification should be used. This expansion is never done inside
-- generics, because otherwise, this breaks the name resolution
-- mechanism for generic instances.
if GNATprove_Mode then
if not Inside_A_Generic then
Expand_SPARK (N);
end if;
Set_Analyzed (N, Full_Analysis);
-- Regular expansion is normally followed by special handling for
-- transient scopes for unconstrained results, etc. but this is not
-- needed, and in general cannot be done correctly, in this mode, so
-- we are all done.
goto Leave;
-- There are three reasons for the Expander_Active flag to be false
-- The first is when are not generating code. In this mode the
-- Full_Analysis flag indicates whether we are performing a complete
-- analysis, in which case Full_Analysis = True or a pre-analysis in
-- which case Full_Analysis = False. See the spec of Sem for more info
-- on this.
-- The second reason for the Expander_Active flag to be False is that
-- we are performing a pre-analysis. During pre-analysis all expansion
-- activity is turned off to make sure nodes are semantically decorated
-- but no extra nodes are generated. This is for instance needed for
-- the first pass of aggregate semantic processing. Note that in this
-- case the Full_Analysis flag is set to False because the node will
-- subsequently be re-analyzed with expansion on (see the spec of sem).
-- Finally, expansion is turned off in a regular compilation if there
-- are serious errors. In that case there will be no further expansion,
-- but one cleanup action may be required: if a transient scope was
-- created (e.g. for a function that returns an unconstrained type) the
-- scope may still be on the stack, and must be removed explicitly,
-- given that the expansion actions that would normally process it will
-- not take place. This prevents cascaded errors due to stack mismatch.
elsif not Expander_Active then
Set_Analyzed (N, Full_Analysis);
if Serious_Errors_Detected > 0 and then Scope_Is_Transient then
(Scope_Stack.Last).Actions_To_Be_Wrapped := (others => No_List);
end if;
goto Leave;
Debug_A_Entry ("expanding ", N);
-- Processing depends on node kind. For full details on the
-- expansion activity required in each case, see bodies of
-- corresponding expand routines.
case Nkind (N) is
when N_Abort_Statement =>
Expand_N_Abort_Statement (N);
-- If -gnatd.B switch was given, crash the compiler. See
-- debug.adb for explanation.
if Debug_Flag_Dot_BB then
raise Abort_Bug_Box_Error;
end if;
when N_Accept_Statement =>
Expand_N_Accept_Statement (N);
when N_Aggregate =>
Expand_N_Aggregate (N);
when N_Allocator =>
Expand_N_Allocator (N);
when N_And_Then =>
Expand_N_And_Then (N);
when N_Assignment_Statement =>
Expand_N_Assignment_Statement (N);
when N_Asynchronous_Select =>
Expand_N_Asynchronous_Select (N);
when N_Attribute_Definition_Clause =>
Expand_N_Attribute_Definition_Clause (N);
when N_Attribute_Reference =>
Expand_N_Attribute_Reference (N);
when N_Block_Statement =>
Expand_N_Block_Statement (N);
when N_Case_Expression =>
Expand_N_Case_Expression (N);
when N_Case_Statement =>
Expand_N_Case_Statement (N);
when N_Conditional_Entry_Call =>
Expand_N_Conditional_Entry_Call (N);
when N_Delay_Relative_Statement =>
Expand_N_Delay_Relative_Statement (N);
when N_Delay_Until_Statement =>
Expand_N_Delay_Until_Statement (N);
when N_Delta_Aggregate =>
Expand_N_Delta_Aggregate (N);
when N_Entry_Body =>
Expand_N_Entry_Body (N);
when N_Entry_Call_Statement =>
Expand_N_Entry_Call_Statement (N);
when N_Entry_Declaration =>
Expand_N_Entry_Declaration (N);
when N_Exception_Declaration =>
Expand_N_Exception_Declaration (N);
when N_Exception_Renaming_Declaration =>
Expand_N_Exception_Renaming_Declaration (N);
when N_Exit_Statement =>
Expand_N_Exit_Statement (N);
when N_Expanded_Name =>
Expand_N_Expanded_Name (N);
when N_Explicit_Dereference =>
Expand_N_Explicit_Dereference (N);
when N_Expression_With_Actions =>
Expand_N_Expression_With_Actions (N);
when N_Extended_Return_Statement =>
Expand_N_Extended_Return_Statement (N);
when N_Extension_Aggregate =>
Expand_N_Extension_Aggregate (N);
when N_Free_Statement =>
Expand_N_Free_Statement (N);
when N_Freeze_Entity =>
Expand_N_Freeze_Entity (N);
when N_Full_Type_Declaration =>
Expand_N_Full_Type_Declaration (N);
when N_Function_Call =>
Expand_N_Function_Call (N);
when N_Generic_Instantiation =>
Expand_N_Generic_Instantiation (N);
when N_Goto_Statement =>
Expand_N_Goto_Statement (N);
when N_Handled_Sequence_Of_Statements =>
Expand_N_Handled_Sequence_Of_Statements (N);
when N_Identifier =>
Expand_N_Identifier (N);
when N_If_Expression =>
Expand_N_If_Expression (N);
when N_Indexed_Component =>
Expand_N_Indexed_Component (N);
when N_If_Statement =>
Expand_N_If_Statement (N);
when N_In =>
Expand_N_In (N);
when N_Loop_Statement =>
Expand_N_Loop_Statement (N);
when N_Not_In =>
Expand_N_Not_In (N);
when N_Null =>
Expand_N_Null (N);
when N_Object_Declaration =>
Expand_N_Object_Declaration (N);
when N_Object_Renaming_Declaration =>
Expand_N_Object_Renaming_Declaration (N);
when N_Op_Add =>
Expand_N_Op_Add (N);
when N_Op_Abs =>
Expand_N_Op_Abs (N);
when N_Op_And =>
Expand_N_Op_And (N);
when N_Op_Concat =>
Expand_N_Op_Concat (N);
when N_Op_Divide =>
Expand_N_Op_Divide (N);
when N_Op_Eq =>
Expand_N_Op_Eq (N);
when N_Op_Expon =>
Expand_N_Op_Expon (N);
when N_Op_Ge =>
Expand_N_Op_Ge (N);
when N_Op_Gt =>
Expand_N_Op_Gt (N);
when N_Op_Le =>
Expand_N_Op_Le (N);
when N_Op_Lt =>
Expand_N_Op_Lt (N);
when N_Op_Minus =>
Expand_N_Op_Minus (N);
when N_Op_Mod =>
Expand_N_Op_Mod (N);
when N_Op_Multiply =>
Expand_N_Op_Multiply (N);
when N_Op_Ne =>
Expand_N_Op_Ne (N);
when N_Op_Not =>
Expand_N_Op_Not (N);
when N_Op_Or =>
Expand_N_Op_Or (N);
when N_Op_Plus =>
Expand_N_Op_Plus (N);
when N_Op_Rem =>
Expand_N_Op_Rem (N);
when N_Op_Rotate_Left =>
Expand_N_Op_Rotate_Left (N);
when N_Op_Rotate_Right =>
Expand_N_Op_Rotate_Right (N);
when N_Op_Shift_Left =>
Expand_N_Op_Shift_Left (N);
when N_Op_Shift_Right =>
Expand_N_Op_Shift_Right (N);
when N_Op_Shift_Right_Arithmetic =>
Expand_N_Op_Shift_Right_Arithmetic (N);
when N_Op_Subtract =>
Expand_N_Op_Subtract (N);
when N_Op_Xor =>
Expand_N_Op_Xor (N);
when N_Or_Else =>
Expand_N_Or_Else (N);
when N_Package_Body =>
Expand_N_Package_Body (N);
when N_Package_Declaration =>
Expand_N_Package_Declaration (N);
when N_Package_Renaming_Declaration =>
Expand_N_Package_Renaming_Declaration (N);
when N_Subprogram_Renaming_Declaration =>
Expand_N_Subprogram_Renaming_Declaration (N);
when N_Pragma =>
Expand_N_Pragma (N);
when N_Procedure_Call_Statement =>
Expand_N_Procedure_Call_Statement (N);
when N_Protected_Type_Declaration =>
Expand_N_Protected_Type_Declaration (N);
when N_Protected_Body =>
Expand_N_Protected_Body (N);
when N_Qualified_Expression =>
Expand_N_Qualified_Expression (N);
when N_Quantified_Expression =>
Expand_N_Quantified_Expression (N);
when N_Raise_Statement =>
Expand_N_Raise_Statement (N);
when N_Raise_Constraint_Error =>
Expand_N_Raise_Constraint_Error (N);
when N_Raise_Expression =>
Expand_N_Raise_Expression (N);
when N_Raise_Program_Error =>
Expand_N_Raise_Program_Error (N);
when N_Raise_Storage_Error =>
Expand_N_Raise_Storage_Error (N);
when N_Real_Literal =>
Expand_N_Real_Literal (N);
when N_Record_Representation_Clause =>
Expand_N_Record_Representation_Clause (N);
when N_Reduction_Expression =>
Expand_N_Reduction_Expression (N);
when N_Requeue_Statement =>
Expand_N_Requeue_Statement (N);
when N_Simple_Return_Statement =>
Expand_N_Simple_Return_Statement (N);
when N_Selected_Component =>
Expand_N_Selected_Component (N);
when N_Selective_Accept =>
Expand_N_Selective_Accept (N);
when N_Single_Protected_Declaration =>
Expand_N_Single_Protected_Declaration (N);
when N_Single_Task_Declaration =>
Expand_N_Single_Task_Declaration (N);
when N_Slice =>
Expand_N_Slice (N);
when N_Subtype_Indication =>
Expand_N_Subtype_Indication (N);
when N_Subprogram_Body =>
Expand_N_Subprogram_Body (N);
when N_Subprogram_Body_Stub =>
Expand_N_Subprogram_Body_Stub (N);
when N_Subprogram_Declaration =>
Expand_N_Subprogram_Declaration (N);
when N_Task_Body =>
Expand_N_Task_Body (N);
when N_Task_Type_Declaration =>
Expand_N_Task_Type_Declaration (N);
when N_Timed_Entry_Call =>
Expand_N_Timed_Entry_Call (N);
when N_Type_Conversion =>
Expand_N_Type_Conversion (N);
when N_Unchecked_Expression =>
Expand_N_Unchecked_Expression (N);
when N_Unchecked_Type_Conversion =>
Expand_N_Unchecked_Type_Conversion (N);
when N_Variant_Part =>
Expand_N_Variant_Part (N);
-- For all other node kinds, no expansion activity required
when others =>
end case;
when RE_Not_Available =>
goto Leave;
-- Set result as analyzed and then do a possible transient wrap. The
-- transient wrap must be done after the Analyzed flag is set on, so
-- that we do not get a recursive attempt to expand the node N.
Set_Analyzed (N);
-- Deal with transient scopes
if Scope_Is_Transient and then N = Node_To_Be_Wrapped then
case Nkind (N) is
when N_Procedure_Call_Statement
| N_Statement_Other_Than_Procedure_Call
Wrap_Transient_Statement (N);
when N_Object_Declaration
| N_Object_Renaming_Declaration
| N_Subtype_Declaration
Wrap_Transient_Declaration (N);
when others =>
Wrap_Transient_Expression (N);
end case;
end if;
Debug_A_Exit ("expanding ", N, " (done)");
end if;
Restore_Ghost_Mode (Saved_GM);
end Expand;
-- Expander_Mode_Restore --
procedure Expander_Mode_Restore is
-- Not active (has no effect) in ASIS and GNATprove modes (see comments
-- in spec of Expander_Mode_Save_And_Set).
if ASIS_Mode or GNATprove_Mode then
end if;
-- Otherwise restore the flag
Expander_Active := Expander_Flags.Table (Expander_Flags.Last);
-- Keep expander off if serious errors detected. In this case we do not
-- need expansion, and continued expansion may cause cascaded errors or
-- compiler bombs.
if Serious_Errors_Detected /= 0 then
Expander_Active := False;
end if;
end Expander_Mode_Restore;
-- Expander_Mode_Save_And_Set --
procedure Expander_Mode_Save_And_Set (Status : Boolean) is
-- Not active (has no effect) in ASIS and GNATprove modes (see comments
-- in spec of Expander_Mode_Save_And_Set).
if ASIS_Mode or GNATprove_Mode then
end if;
-- Otherwise save and set the flag
Expander_Flags.Table (Expander_Flags.Last) := Expander_Active;
Expander_Active := Status;
end Expander_Mode_Save_And_Set;
end Expander;