aboutsummaryrefslogtreecommitdiffstats
path: root/gcc-4.8.3/gcc/ada/exp_ch5.adb
diff options
context:
space:
mode:
Diffstat (limited to 'gcc-4.8.3/gcc/ada/exp_ch5.adb')
-rw-r--r--gcc-4.8.3/gcc/ada/exp_ch5.adb4454
1 files changed, 4454 insertions, 0 deletions
diff --git a/gcc-4.8.3/gcc/ada/exp_ch5.adb b/gcc-4.8.3/gcc/ada/exp_ch5.adb
new file mode 100644
index 000000000..243279b00
--- /dev/null
+++ b/gcc-4.8.3/gcc/ada/exp_ch5.adb
@@ -0,0 +1,4454 @@
+------------------------------------------------------------------------------
+-- --
+-- GNAT COMPILER COMPONENTS --
+-- --
+-- E X P _ C H 5 --
+-- --
+-- B o d y --
+-- --
+-- Copyright (C) 1992-2013, 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 --
+-- http://www.gnu.org/licenses 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 Aspects; use Aspects;
+with Atree; use Atree;
+with Checks; use Checks;
+with Debug; use Debug;
+with Einfo; use Einfo;
+with Elists; use Elists;
+with Errout; use Errout;
+with Exp_Aggr; use Exp_Aggr;
+with Exp_Ch6; use Exp_Ch6;
+with Exp_Ch7; use Exp_Ch7;
+with Exp_Ch11; use Exp_Ch11;
+with Exp_Dbug; use Exp_Dbug;
+with Exp_Pakd; use Exp_Pakd;
+with Exp_Tss; use Exp_Tss;
+with Exp_Util; use Exp_Util;
+with Namet; use Namet;
+with Nlists; use Nlists;
+with Nmake; use Nmake;
+with Opt; use Opt;
+with Restrict; use Restrict;
+with Rident; use Rident;
+with Rtsfind; use Rtsfind;
+with Sinfo; use Sinfo;
+with Sem; use Sem;
+with Sem_Aux; use Sem_Aux;
+with Sem_Ch3; use Sem_Ch3;
+with Sem_Ch8; use Sem_Ch8;
+with Sem_Ch13; use Sem_Ch13;
+with Sem_Eval; use Sem_Eval;
+with Sem_Res; use Sem_Res;
+with Sem_Util; use Sem_Util;
+with Snames; use Snames;
+with Stand; use Stand;
+with Stringt; use Stringt;
+with Targparm; use Targparm;
+with Tbuild; use Tbuild;
+with Validsw; use Validsw;
+
+package body Exp_Ch5 is
+
+ function Change_Of_Representation (N : Node_Id) return Boolean;
+ -- Determine if the right hand side of assignment N is a type conversion
+ -- which requires a change of representation. Called only for the array
+ -- and record cases.
+
+ procedure Expand_Assign_Array (N : Node_Id; Rhs : Node_Id);
+ -- N is an assignment which assigns an array value. This routine process
+ -- the various special cases and checks required for such assignments,
+ -- including change of representation. Rhs is normally simply the right
+ -- hand side of the assignment, except that if the right hand side is a
+ -- type conversion or a qualified expression, then the RHS is the actual
+ -- expression inside any such type conversions or qualifications.
+
+ function Expand_Assign_Array_Loop
+ (N : Node_Id;
+ Larray : Entity_Id;
+ Rarray : Entity_Id;
+ L_Type : Entity_Id;
+ R_Type : Entity_Id;
+ Ndim : Pos;
+ Rev : Boolean) return Node_Id;
+ -- N is an assignment statement which assigns an array value. This routine
+ -- expands the assignment into a loop (or nested loops for the case of a
+ -- multi-dimensional array) to do the assignment component by component.
+ -- Larray and Rarray are the entities of the actual arrays on the left
+ -- hand and right hand sides. L_Type and R_Type are the types of these
+ -- arrays (which may not be the same, due to either sliding, or to a
+ -- change of representation case). Ndim is the number of dimensions and
+ -- the parameter Rev indicates if the loops run normally (Rev = False),
+ -- or reversed (Rev = True). The value returned is the constructed
+ -- loop statement. Auxiliary declarations are inserted before node N
+ -- using the standard Insert_Actions mechanism.
+
+ procedure Expand_Assign_Record (N : Node_Id);
+ -- N is an assignment of a non-tagged record value. This routine handles
+ -- the case where the assignment must be made component by component,
+ -- either because the target is not byte aligned, or there is a change
+ -- of representation, or when we have a tagged type with a representation
+ -- clause (this last case is required because holes in the tagged type
+ -- might be filled with components from child types).
+
+ procedure Expand_Iterator_Loop (N : Node_Id);
+ -- Expand loop over arrays and containers that uses the form "for X of C"
+ -- with an optional subtype mark, or "for Y in C".
+
+ procedure Expand_Iterator_Loop_Over_Array (N : Node_Id);
+ -- Expand loop over arrays that uses the form "for X of C"
+
+ procedure Expand_Loop_Entry_Attributes (N : Node_Id);
+ -- Given a loop statement subject to at least one Loop_Entry attribute,
+ -- expand both the loop and all related Loop_Entry references.
+
+ procedure Expand_Predicated_Loop (N : Node_Id);
+ -- Expand for loop over predicated subtype
+
+ function Make_Tag_Ctrl_Assignment (N : Node_Id) return List_Id;
+ -- Generate the necessary code for controlled and tagged assignment, that
+ -- is to say, finalization of the target before, adjustment of the target
+ -- after and save and restore of the tag and finalization pointers which
+ -- are not 'part of the value' and must not be changed upon assignment. N
+ -- is the original Assignment node.
+
+ ------------------------------
+ -- Change_Of_Representation --
+ ------------------------------
+
+ function Change_Of_Representation (N : Node_Id) return Boolean is
+ Rhs : constant Node_Id := Expression (N);
+ begin
+ return
+ Nkind (Rhs) = N_Type_Conversion
+ and then
+ not Same_Representation (Etype (Rhs), Etype (Expression (Rhs)));
+ end Change_Of_Representation;
+
+ -------------------------
+ -- Expand_Assign_Array --
+ -------------------------
+
+ -- There are two issues here. First, do we let Gigi do a block move, or
+ -- do we expand out into a loop? Second, we need to set the two flags
+ -- Forwards_OK and Backwards_OK which show whether the block move (or
+ -- corresponding loops) can be legitimately done in a forwards (low to
+ -- high) or backwards (high to low) manner.
+
+ procedure Expand_Assign_Array (N : Node_Id; Rhs : Node_Id) is
+ Loc : constant Source_Ptr := Sloc (N);
+
+ Lhs : constant Node_Id := Name (N);
+
+ Act_Lhs : constant Node_Id := Get_Referenced_Object (Lhs);
+ Act_Rhs : Node_Id := Get_Referenced_Object (Rhs);
+
+ L_Type : constant Entity_Id :=
+ Underlying_Type (Get_Actual_Subtype (Act_Lhs));
+ R_Type : Entity_Id :=
+ Underlying_Type (Get_Actual_Subtype (Act_Rhs));
+
+ L_Slice : constant Boolean := Nkind (Act_Lhs) = N_Slice;
+ R_Slice : constant Boolean := Nkind (Act_Rhs) = N_Slice;
+
+ Crep : constant Boolean := Change_Of_Representation (N);
+
+ Larray : Node_Id;
+ Rarray : Node_Id;
+
+ Ndim : constant Pos := Number_Dimensions (L_Type);
+
+ Loop_Required : Boolean := False;
+ -- This switch is set to True if the array move must be done using
+ -- an explicit front end generated loop.
+
+ procedure Apply_Dereference (Arg : Node_Id);
+ -- If the argument is an access to an array, and the assignment is
+ -- converted into a procedure call, apply explicit dereference.
+
+ function Has_Address_Clause (Exp : Node_Id) return Boolean;
+ -- Test if Exp is a reference to an array whose declaration has
+ -- an address clause, or it is a slice of such an array.
+
+ function Is_Formal_Array (Exp : Node_Id) return Boolean;
+ -- Test if Exp is a reference to an array which is either a formal
+ -- parameter or a slice of a formal parameter. These are the cases
+ -- where hidden aliasing can occur.
+
+ function Is_Non_Local_Array (Exp : Node_Id) return Boolean;
+ -- Determine if Exp is a reference to an array variable which is other
+ -- than an object defined in the current scope, or a slice of such
+ -- an object. Such objects can be aliased to parameters (unlike local
+ -- array references).
+
+ -----------------------
+ -- Apply_Dereference --
+ -----------------------
+
+ procedure Apply_Dereference (Arg : Node_Id) is
+ Typ : constant Entity_Id := Etype (Arg);
+ begin
+ if Is_Access_Type (Typ) then
+ Rewrite (Arg, Make_Explicit_Dereference (Loc,
+ Prefix => Relocate_Node (Arg)));
+ Analyze_And_Resolve (Arg, Designated_Type (Typ));
+ end if;
+ end Apply_Dereference;
+
+ ------------------------
+ -- Has_Address_Clause --
+ ------------------------
+
+ function Has_Address_Clause (Exp : Node_Id) return Boolean is
+ begin
+ return
+ (Is_Entity_Name (Exp) and then
+ Present (Address_Clause (Entity (Exp))))
+ or else
+ (Nkind (Exp) = N_Slice and then Has_Address_Clause (Prefix (Exp)));
+ end Has_Address_Clause;
+
+ ---------------------
+ -- Is_Formal_Array --
+ ---------------------
+
+ function Is_Formal_Array (Exp : Node_Id) return Boolean is
+ begin
+ return
+ (Is_Entity_Name (Exp) and then Is_Formal (Entity (Exp)))
+ or else
+ (Nkind (Exp) = N_Slice and then Is_Formal_Array (Prefix (Exp)));
+ end Is_Formal_Array;
+
+ ------------------------
+ -- Is_Non_Local_Array --
+ ------------------------
+
+ function Is_Non_Local_Array (Exp : Node_Id) return Boolean is
+ begin
+ return (Is_Entity_Name (Exp)
+ and then Scope (Entity (Exp)) /= Current_Scope)
+ or else (Nkind (Exp) = N_Slice
+ and then Is_Non_Local_Array (Prefix (Exp)));
+ end Is_Non_Local_Array;
+
+ -- Determine if Lhs, Rhs are formal arrays or nonlocal arrays
+
+ Lhs_Formal : constant Boolean := Is_Formal_Array (Act_Lhs);
+ Rhs_Formal : constant Boolean := Is_Formal_Array (Act_Rhs);
+
+ Lhs_Non_Local_Var : constant Boolean := Is_Non_Local_Array (Act_Lhs);
+ Rhs_Non_Local_Var : constant Boolean := Is_Non_Local_Array (Act_Rhs);
+
+ -- Start of processing for Expand_Assign_Array
+
+ begin
+ -- Deal with length check. Note that the length check is done with
+ -- respect to the right hand side as given, not a possible underlying
+ -- renamed object, since this would generate incorrect extra checks.
+
+ Apply_Length_Check (Rhs, L_Type);
+
+ -- We start by assuming that the move can be done in either direction,
+ -- i.e. that the two sides are completely disjoint.
+
+ Set_Forwards_OK (N, True);
+ Set_Backwards_OK (N, True);
+
+ -- Normally it is only the slice case that can lead to overlap, and
+ -- explicit checks for slices are made below. But there is one case
+ -- where the slice can be implicit and invisible to us: when we have a
+ -- one dimensional array, and either both operands are parameters, or
+ -- one is a parameter (which can be a slice passed by reference) and the
+ -- other is a non-local variable. In this case the parameter could be a
+ -- slice that overlaps with the other operand.
+
+ -- However, if the array subtype is a constrained first subtype in the
+ -- parameter case, then we don't have to worry about overlap, since
+ -- slice assignments aren't possible (other than for a slice denoting
+ -- the whole array).
+
+ -- Note: No overlap is possible if there is a change of representation,
+ -- so we can exclude this case.
+
+ if Ndim = 1
+ and then not Crep
+ and then
+ ((Lhs_Formal and Rhs_Formal)
+ or else
+ (Lhs_Formal and Rhs_Non_Local_Var)
+ or else
+ (Rhs_Formal and Lhs_Non_Local_Var))
+ and then
+ (not Is_Constrained (Etype (Lhs))
+ or else not Is_First_Subtype (Etype (Lhs)))
+
+ -- In the case of compiling for the Java or .NET Virtual Machine,
+ -- slices are always passed by making a copy, so we don't have to
+ -- worry about overlap. We also want to prevent generation of "<"
+ -- comparisons for array addresses, since that's a meaningless
+ -- operation on the VM.
+
+ and then VM_Target = No_VM
+ then
+ Set_Forwards_OK (N, False);
+ Set_Backwards_OK (N, False);
+
+ -- Note: the bit-packed case is not worrisome here, since if we have
+ -- a slice passed as a parameter, it is always aligned on a byte
+ -- boundary, and if there are no explicit slices, the assignment
+ -- can be performed directly.
+ end if;
+
+ -- If either operand has an address clause clear Backwards_OK and
+ -- Forwards_OK, since we cannot tell if the operands overlap. We
+ -- exclude this treatment when Rhs is an aggregate, since we know
+ -- that overlap can't occur.
+
+ if (Has_Address_Clause (Lhs) and then Nkind (Rhs) /= N_Aggregate)
+ or else Has_Address_Clause (Rhs)
+ then
+ Set_Forwards_OK (N, False);
+ Set_Backwards_OK (N, False);
+ end if;
+
+ -- We certainly must use a loop for change of representation and also
+ -- we use the operand of the conversion on the right hand side as the
+ -- effective right hand side (the component types must match in this
+ -- situation).
+
+ if Crep then
+ Act_Rhs := Get_Referenced_Object (Rhs);
+ R_Type := Get_Actual_Subtype (Act_Rhs);
+ Loop_Required := True;
+
+ -- We require a loop if the left side is possibly bit unaligned
+
+ elsif Possible_Bit_Aligned_Component (Lhs)
+ or else
+ Possible_Bit_Aligned_Component (Rhs)
+ then
+ Loop_Required := True;
+
+ -- Arrays with controlled components are expanded into a loop to force
+ -- calls to Adjust at the component level.
+
+ elsif Has_Controlled_Component (L_Type) then
+ Loop_Required := True;
+
+ -- If object is atomic, we cannot tolerate a loop
+
+ elsif Is_Atomic_Object (Act_Lhs)
+ or else
+ Is_Atomic_Object (Act_Rhs)
+ then
+ return;
+
+ -- Loop is required if we have atomic components since we have to
+ -- be sure to do any accesses on an element by element basis.
+
+ elsif Has_Atomic_Components (L_Type)
+ or else Has_Atomic_Components (R_Type)
+ or else Is_Atomic (Component_Type (L_Type))
+ or else Is_Atomic (Component_Type (R_Type))
+ then
+ Loop_Required := True;
+
+ -- Case where no slice is involved
+
+ elsif not L_Slice and not R_Slice then
+
+ -- The following code deals with the case of unconstrained bit packed
+ -- arrays. The problem is that the template for such arrays contains
+ -- the bounds of the actual source level array, but the copy of an
+ -- entire array requires the bounds of the underlying array. It would
+ -- be nice if the back end could take care of this, but right now it
+ -- does not know how, so if we have such a type, then we expand out
+ -- into a loop, which is inefficient but works correctly. If we don't
+ -- do this, we get the wrong length computed for the array to be
+ -- moved. The two cases we need to worry about are:
+
+ -- Explicit dereference of an unconstrained packed array type as in
+ -- the following example:
+
+ -- procedure C52 is
+ -- type BITS is array(INTEGER range <>) of BOOLEAN;
+ -- pragma PACK(BITS);
+ -- type A is access BITS;
+ -- P1,P2 : A;
+ -- begin
+ -- P1 := new BITS (1 .. 65_535);
+ -- P2 := new BITS (1 .. 65_535);
+ -- P2.ALL := P1.ALL;
+ -- end C52;
+
+ -- A formal parameter reference with an unconstrained bit array type
+ -- is the other case we need to worry about (here we assume the same
+ -- BITS type declared above):
+
+ -- procedure Write_All (File : out BITS; Contents : BITS);
+ -- begin
+ -- File.Storage := Contents;
+ -- end Write_All;
+
+ -- We expand to a loop in either of these two cases
+
+ -- Question for future thought. Another potentially more efficient
+ -- approach would be to create the actual subtype, and then do an
+ -- unchecked conversion to this actual subtype ???
+
+ Check_Unconstrained_Bit_Packed_Array : declare
+
+ function Is_UBPA_Reference (Opnd : Node_Id) return Boolean;
+ -- Function to perform required test for the first case, above
+ -- (dereference of an unconstrained bit packed array).
+
+ -----------------------
+ -- Is_UBPA_Reference --
+ -----------------------
+
+ function Is_UBPA_Reference (Opnd : Node_Id) return Boolean is
+ Typ : constant Entity_Id := Underlying_Type (Etype (Opnd));
+ P_Type : Entity_Id;
+ Des_Type : Entity_Id;
+
+ begin
+ if Present (Packed_Array_Type (Typ))
+ and then Is_Array_Type (Packed_Array_Type (Typ))
+ and then not Is_Constrained (Packed_Array_Type (Typ))
+ then
+ return True;
+
+ elsif Nkind (Opnd) = N_Explicit_Dereference then
+ P_Type := Underlying_Type (Etype (Prefix (Opnd)));
+
+ if not Is_Access_Type (P_Type) then
+ return False;
+
+ else
+ Des_Type := Designated_Type (P_Type);
+ return
+ Is_Bit_Packed_Array (Des_Type)
+ and then not Is_Constrained (Des_Type);
+ end if;
+
+ else
+ return False;
+ end if;
+ end Is_UBPA_Reference;
+
+ -- Start of processing for Check_Unconstrained_Bit_Packed_Array
+
+ begin
+ if Is_UBPA_Reference (Lhs)
+ or else
+ Is_UBPA_Reference (Rhs)
+ then
+ Loop_Required := True;
+
+ -- Here if we do not have the case of a reference to a bit packed
+ -- unconstrained array case. In this case gigi can most certainly
+ -- handle the assignment if a forwards move is allowed.
+
+ -- (could it handle the backwards case also???)
+
+ elsif Forwards_OK (N) then
+ return;
+ end if;
+ end Check_Unconstrained_Bit_Packed_Array;
+
+ -- The back end can always handle the assignment if the right side is a
+ -- string literal (note that overlap is definitely impossible in this
+ -- case). If the type is packed, a string literal is always converted
+ -- into an aggregate, except in the case of a null slice, for which no
+ -- aggregate can be written. In that case, rewrite the assignment as a
+ -- null statement, a length check has already been emitted to verify
+ -- that the range of the left-hand side is empty.
+
+ -- Note that this code is not executed if we have an assignment of a
+ -- string literal to a non-bit aligned component of a record, a case
+ -- which cannot be handled by the backend.
+
+ elsif Nkind (Rhs) = N_String_Literal then
+ if String_Length (Strval (Rhs)) = 0
+ and then Is_Bit_Packed_Array (L_Type)
+ then
+ Rewrite (N, Make_Null_Statement (Loc));
+ Analyze (N);
+ end if;
+
+ return;
+
+ -- If either operand is bit packed, then we need a loop, since we can't
+ -- be sure that the slice is byte aligned. Similarly, if either operand
+ -- is a possibly unaligned slice, then we need a loop (since the back
+ -- end cannot handle unaligned slices).
+
+ elsif Is_Bit_Packed_Array (L_Type)
+ or else Is_Bit_Packed_Array (R_Type)
+ or else Is_Possibly_Unaligned_Slice (Lhs)
+ or else Is_Possibly_Unaligned_Slice (Rhs)
+ then
+ Loop_Required := True;
+
+ -- If we are not bit-packed, and we have only one slice, then no overlap
+ -- is possible except in the parameter case, so we can let the back end
+ -- handle things.
+
+ elsif not (L_Slice and R_Slice) then
+ if Forwards_OK (N) then
+ return;
+ end if;
+ end if;
+
+ -- If the right-hand side is a string literal, introduce a temporary for
+ -- it, for use in the generated loop that will follow.
+
+ if Nkind (Rhs) = N_String_Literal then
+ declare
+ Temp : constant Entity_Id := Make_Temporary (Loc, 'T', Rhs);
+ Decl : Node_Id;
+
+ begin
+ Decl :=
+ Make_Object_Declaration (Loc,
+ Defining_Identifier => Temp,
+ Object_Definition => New_Occurrence_Of (L_Type, Loc),
+ Expression => Relocate_Node (Rhs));
+
+ Insert_Action (N, Decl);
+ Rewrite (Rhs, New_Occurrence_Of (Temp, Loc));
+ R_Type := Etype (Temp);
+ end;
+ end if;
+
+ -- Come here to complete the analysis
+
+ -- Loop_Required: Set to True if we know that a loop is required
+ -- regardless of overlap considerations.
+
+ -- Forwards_OK: Set to False if we already know that a forwards
+ -- move is not safe, else set to True.
+
+ -- Backwards_OK: Set to False if we already know that a backwards
+ -- move is not safe, else set to True
+
+ -- Our task at this stage is to complete the overlap analysis, which can
+ -- result in possibly setting Forwards_OK or Backwards_OK to False, and
+ -- then generating the final code, either by deciding that it is OK
+ -- after all to let Gigi handle it, or by generating appropriate code
+ -- in the front end.
+
+ declare
+ L_Index_Typ : constant Node_Id := Etype (First_Index (L_Type));
+ R_Index_Typ : constant Node_Id := Etype (First_Index (R_Type));
+
+ Left_Lo : constant Node_Id := Type_Low_Bound (L_Index_Typ);
+ Left_Hi : constant Node_Id := Type_High_Bound (L_Index_Typ);
+ Right_Lo : constant Node_Id := Type_Low_Bound (R_Index_Typ);
+ Right_Hi : constant Node_Id := Type_High_Bound (R_Index_Typ);
+
+ Act_L_Array : Node_Id;
+ Act_R_Array : Node_Id;
+
+ Cleft_Lo : Node_Id;
+ Cright_Lo : Node_Id;
+ Condition : Node_Id;
+
+ Cresult : Compare_Result;
+
+ begin
+ -- Get the expressions for the arrays. If we are dealing with a
+ -- private type, then convert to the underlying type. We can do
+ -- direct assignments to an array that is a private type, but we
+ -- cannot assign to elements of the array without this extra
+ -- unchecked conversion.
+
+ -- Note: We propagate Parent to the conversion nodes to generate
+ -- a well-formed subtree.
+
+ if Nkind (Act_Lhs) = N_Slice then
+ Larray := Prefix (Act_Lhs);
+ else
+ Larray := Act_Lhs;
+
+ if Is_Private_Type (Etype (Larray)) then
+ declare
+ Par : constant Node_Id := Parent (Larray);
+ begin
+ Larray :=
+ Unchecked_Convert_To
+ (Underlying_Type (Etype (Larray)), Larray);
+ Set_Parent (Larray, Par);
+ end;
+ end if;
+ end if;
+
+ if Nkind (Act_Rhs) = N_Slice then
+ Rarray := Prefix (Act_Rhs);
+ else
+ Rarray := Act_Rhs;
+
+ if Is_Private_Type (Etype (Rarray)) then
+ declare
+ Par : constant Node_Id := Parent (Rarray);
+ begin
+ Rarray :=
+ Unchecked_Convert_To
+ (Underlying_Type (Etype (Rarray)), Rarray);
+ Set_Parent (Rarray, Par);
+ end;
+ end if;
+ end if;
+
+ -- If both sides are slices, we must figure out whether it is safe
+ -- to do the move in one direction or the other. It is always safe
+ -- if there is a change of representation since obviously two arrays
+ -- with different representations cannot possibly overlap.
+
+ if (not Crep) and L_Slice and R_Slice then
+ Act_L_Array := Get_Referenced_Object (Prefix (Act_Lhs));
+ Act_R_Array := Get_Referenced_Object (Prefix (Act_Rhs));
+
+ -- If both left and right hand arrays are entity names, and refer
+ -- to different entities, then we know that the move is safe (the
+ -- two storage areas are completely disjoint).
+
+ if Is_Entity_Name (Act_L_Array)
+ and then Is_Entity_Name (Act_R_Array)
+ and then Entity (Act_L_Array) /= Entity (Act_R_Array)
+ then
+ null;
+
+ -- Otherwise, we assume the worst, which is that the two arrays
+ -- are the same array. There is no need to check if we know that
+ -- is the case, because if we don't know it, we still have to
+ -- assume it!
+
+ -- Generally if the same array is involved, then we have an
+ -- overlapping case. We will have to really assume the worst (i.e.
+ -- set neither of the OK flags) unless we can determine the lower
+ -- or upper bounds at compile time and compare them.
+
+ else
+ Cresult :=
+ Compile_Time_Compare
+ (Left_Lo, Right_Lo, Assume_Valid => True);
+
+ if Cresult = Unknown then
+ Cresult :=
+ Compile_Time_Compare
+ (Left_Hi, Right_Hi, Assume_Valid => True);
+ end if;
+
+ case Cresult is
+ when LT | LE | EQ => Set_Backwards_OK (N, False);
+ when GT | GE => Set_Forwards_OK (N, False);
+ when NE | Unknown => Set_Backwards_OK (N, False);
+ Set_Forwards_OK (N, False);
+ end case;
+ end if;
+ end if;
+
+ -- If after that analysis Loop_Required is False, meaning that we
+ -- have not discovered some non-overlap reason for requiring a loop,
+ -- then the outcome depends on the capabilities of the back end.
+
+ if not Loop_Required then
+
+ -- The GCC back end can deal with all cases of overlap by falling
+ -- back to memmove if it cannot use a more efficient approach.
+
+ if VM_Target = No_VM and not AAMP_On_Target then
+ return;
+
+ -- Assume other back ends can handle it if Forwards_OK is set
+
+ elsif Forwards_OK (N) then
+ return;
+
+ -- If Forwards_OK is not set, the back end will need something
+ -- like memmove to handle the move. For now, this processing is
+ -- activated using the .s debug flag (-gnatd.s).
+
+ elsif Debug_Flag_Dot_S then
+ return;
+ end if;
+ end if;
+
+ -- At this stage we have to generate an explicit loop, and we have
+ -- the following cases:
+
+ -- Forwards_OK = True
+
+ -- Rnn : right_index := right_index'First;
+ -- for Lnn in left-index loop
+ -- left (Lnn) := right (Rnn);
+ -- Rnn := right_index'Succ (Rnn);
+ -- end loop;
+
+ -- Note: the above code MUST be analyzed with checks off, because
+ -- otherwise the Succ could overflow. But in any case this is more
+ -- efficient!
+
+ -- Forwards_OK = False, Backwards_OK = True
+
+ -- Rnn : right_index := right_index'Last;
+ -- for Lnn in reverse left-index loop
+ -- left (Lnn) := right (Rnn);
+ -- Rnn := right_index'Pred (Rnn);
+ -- end loop;
+
+ -- Note: the above code MUST be analyzed with checks off, because
+ -- otherwise the Pred could overflow. But in any case this is more
+ -- efficient!
+
+ -- Forwards_OK = Backwards_OK = False
+
+ -- This only happens if we have the same array on each side. It is
+ -- possible to create situations using overlays that violate this,
+ -- but we simply do not promise to get this "right" in this case.
+
+ -- There are two possible subcases. If the No_Implicit_Conditionals
+ -- restriction is set, then we generate the following code:
+
+ -- declare
+ -- T : constant <operand-type> := rhs;
+ -- begin
+ -- lhs := T;
+ -- end;
+
+ -- If implicit conditionals are permitted, then we generate:
+
+ -- if Left_Lo <= Right_Lo then
+ -- <code for Forwards_OK = True above>
+ -- else
+ -- <code for Backwards_OK = True above>
+ -- end if;
+
+ -- In order to detect possible aliasing, we examine the renamed
+ -- expression when the source or target is a renaming. However,
+ -- the renaming may be intended to capture an address that may be
+ -- affected by subsequent code, and therefore we must recover
+ -- the actual entity for the expansion that follows, not the
+ -- object it renames. In particular, if source or target designate
+ -- a portion of a dynamically allocated object, the pointer to it
+ -- may be reassigned but the renaming preserves the proper location.
+
+ if Is_Entity_Name (Rhs)
+ and then
+ Nkind (Parent (Entity (Rhs))) = N_Object_Renaming_Declaration
+ and then Nkind (Act_Rhs) = N_Slice
+ then
+ Rarray := Rhs;
+ end if;
+
+ if Is_Entity_Name (Lhs)
+ and then
+ Nkind (Parent (Entity (Lhs))) = N_Object_Renaming_Declaration
+ and then Nkind (Act_Lhs) = N_Slice
+ then
+ Larray := Lhs;
+ end if;
+
+ -- Cases where either Forwards_OK or Backwards_OK is true
+
+ if Forwards_OK (N) or else Backwards_OK (N) then
+ if Needs_Finalization (Component_Type (L_Type))
+ and then Base_Type (L_Type) = Base_Type (R_Type)
+ and then Ndim = 1
+ and then not No_Ctrl_Actions (N)
+ then
+ declare
+ Proc : constant Entity_Id :=
+ TSS (Base_Type (L_Type), TSS_Slice_Assign);
+ Actuals : List_Id;
+
+ begin
+ Apply_Dereference (Larray);
+ Apply_Dereference (Rarray);
+ Actuals := New_List (
+ Duplicate_Subexpr (Larray, Name_Req => True),
+ Duplicate_Subexpr (Rarray, Name_Req => True),
+ Duplicate_Subexpr (Left_Lo, Name_Req => True),
+ Duplicate_Subexpr (Left_Hi, Name_Req => True),
+ Duplicate_Subexpr (Right_Lo, Name_Req => True),
+ Duplicate_Subexpr (Right_Hi, Name_Req => True));
+
+ Append_To (Actuals,
+ New_Occurrence_Of (
+ Boolean_Literals (not Forwards_OK (N)), Loc));
+
+ Rewrite (N,
+ Make_Procedure_Call_Statement (Loc,
+ Name => New_Reference_To (Proc, Loc),
+ Parameter_Associations => Actuals));
+ end;
+
+ else
+ Rewrite (N,
+ Expand_Assign_Array_Loop
+ (N, Larray, Rarray, L_Type, R_Type, Ndim,
+ Rev => not Forwards_OK (N)));
+ end if;
+
+ -- Case of both are false with No_Implicit_Conditionals
+
+ elsif Restriction_Active (No_Implicit_Conditionals) then
+ declare
+ T : constant Entity_Id :=
+ Make_Defining_Identifier (Loc, Chars => Name_T);
+
+ begin
+ Rewrite (N,
+ Make_Block_Statement (Loc,
+ Declarations => New_List (
+ Make_Object_Declaration (Loc,
+ Defining_Identifier => T,
+ Constant_Present => True,
+ Object_Definition =>
+ New_Occurrence_Of (Etype (Rhs), Loc),
+ Expression => Relocate_Node (Rhs))),
+
+ Handled_Statement_Sequence =>
+ Make_Handled_Sequence_Of_Statements (Loc,
+ Statements => New_List (
+ Make_Assignment_Statement (Loc,
+ Name => Relocate_Node (Lhs),
+ Expression => New_Occurrence_Of (T, Loc))))));
+ end;
+
+ -- Case of both are false with implicit conditionals allowed
+
+ else
+ -- Before we generate this code, we must ensure that the left and
+ -- right side array types are defined. They may be itypes, and we
+ -- cannot let them be defined inside the if, since the first use
+ -- in the then may not be executed.
+
+ Ensure_Defined (L_Type, N);
+ Ensure_Defined (R_Type, N);
+
+ -- We normally compare addresses to find out which way round to
+ -- do the loop, since this is reliable, and handles the cases of
+ -- parameters, conversions etc. But we can't do that in the bit
+ -- packed case or the VM case, because addresses don't work there.
+
+ if not Is_Bit_Packed_Array (L_Type) and then VM_Target = No_VM then
+ Condition :=
+ Make_Op_Le (Loc,
+ Left_Opnd =>
+ Unchecked_Convert_To (RTE (RE_Integer_Address),
+ Make_Attribute_Reference (Loc,
+ Prefix =>
+ Make_Indexed_Component (Loc,
+ Prefix =>
+ Duplicate_Subexpr_Move_Checks (Larray, True),
+ Expressions => New_List (
+ Make_Attribute_Reference (Loc,
+ Prefix =>
+ New_Reference_To
+ (L_Index_Typ, Loc),
+ Attribute_Name => Name_First))),
+ Attribute_Name => Name_Address)),
+
+ Right_Opnd =>
+ Unchecked_Convert_To (RTE (RE_Integer_Address),
+ Make_Attribute_Reference (Loc,
+ Prefix =>
+ Make_Indexed_Component (Loc,
+ Prefix =>
+ Duplicate_Subexpr_Move_Checks (Rarray, True),
+ Expressions => New_List (
+ Make_Attribute_Reference (Loc,
+ Prefix =>
+ New_Reference_To
+ (R_Index_Typ, Loc),
+ Attribute_Name => Name_First))),
+ Attribute_Name => Name_Address)));
+
+ -- For the bit packed and VM cases we use the bounds. That's OK,
+ -- because we don't have to worry about parameters, since they
+ -- cannot cause overlap. Perhaps we should worry about weird slice
+ -- conversions ???
+
+ else
+ -- Copy the bounds
+
+ Cleft_Lo := New_Copy_Tree (Left_Lo);
+ Cright_Lo := New_Copy_Tree (Right_Lo);
+
+ -- If the types do not match we add an implicit conversion
+ -- here to ensure proper match
+
+ if Etype (Left_Lo) /= Etype (Right_Lo) then
+ Cright_Lo :=
+ Unchecked_Convert_To (Etype (Left_Lo), Cright_Lo);
+ end if;
+
+ -- Reset the Analyzed flag, because the bounds of the index
+ -- type itself may be universal, and must must be reanalyzed
+ -- to acquire the proper type for the back end.
+
+ Set_Analyzed (Cleft_Lo, False);
+ Set_Analyzed (Cright_Lo, False);
+
+ Condition :=
+ Make_Op_Le (Loc,
+ Left_Opnd => Cleft_Lo,
+ Right_Opnd => Cright_Lo);
+ end if;
+
+ if Needs_Finalization (Component_Type (L_Type))
+ and then Base_Type (L_Type) = Base_Type (R_Type)
+ and then Ndim = 1
+ and then not No_Ctrl_Actions (N)
+ then
+
+ -- Call TSS procedure for array assignment, passing the
+ -- explicit bounds of right and left hand sides.
+
+ declare
+ Proc : constant Entity_Id :=
+ TSS (Base_Type (L_Type), TSS_Slice_Assign);
+ Actuals : List_Id;
+
+ begin
+ Apply_Dereference (Larray);
+ Apply_Dereference (Rarray);
+ Actuals := New_List (
+ Duplicate_Subexpr (Larray, Name_Req => True),
+ Duplicate_Subexpr (Rarray, Name_Req => True),
+ Duplicate_Subexpr (Left_Lo, Name_Req => True),
+ Duplicate_Subexpr (Left_Hi, Name_Req => True),
+ Duplicate_Subexpr (Right_Lo, Name_Req => True),
+ Duplicate_Subexpr (Right_Hi, Name_Req => True));
+
+ Append_To (Actuals,
+ Make_Op_Not (Loc,
+ Right_Opnd => Condition));
+
+ Rewrite (N,
+ Make_Procedure_Call_Statement (Loc,
+ Name => New_Reference_To (Proc, Loc),
+ Parameter_Associations => Actuals));
+ end;
+
+ else
+ Rewrite (N,
+ Make_Implicit_If_Statement (N,
+ Condition => Condition,
+
+ Then_Statements => New_List (
+ Expand_Assign_Array_Loop
+ (N, Larray, Rarray, L_Type, R_Type, Ndim,
+ Rev => False)),
+
+ Else_Statements => New_List (
+ Expand_Assign_Array_Loop
+ (N, Larray, Rarray, L_Type, R_Type, Ndim,
+ Rev => True))));
+ end if;
+ end if;
+
+ Analyze (N, Suppress => All_Checks);
+ end;
+
+ exception
+ when RE_Not_Available =>
+ return;
+ end Expand_Assign_Array;
+
+ ------------------------------
+ -- Expand_Assign_Array_Loop --
+ ------------------------------
+
+ -- The following is an example of the loop generated for the case of a
+ -- two-dimensional array:
+
+ -- declare
+ -- R2b : Tm1X1 := 1;
+ -- begin
+ -- for L1b in 1 .. 100 loop
+ -- declare
+ -- R4b : Tm1X2 := 1;
+ -- begin
+ -- for L3b in 1 .. 100 loop
+ -- vm1 (L1b, L3b) := vm2 (R2b, R4b);
+ -- R4b := Tm1X2'succ(R4b);
+ -- end loop;
+ -- end;
+ -- R2b := Tm1X1'succ(R2b);
+ -- end loop;
+ -- end;
+
+ -- Here Rev is False, and Tm1Xn are the subscript types for the right hand
+ -- side. The declarations of R2b and R4b are inserted before the original
+ -- assignment statement.
+
+ function Expand_Assign_Array_Loop
+ (N : Node_Id;
+ Larray : Entity_Id;
+ Rarray : Entity_Id;
+ L_Type : Entity_Id;
+ R_Type : Entity_Id;
+ Ndim : Pos;
+ Rev : Boolean) return Node_Id
+ is
+ Loc : constant Source_Ptr := Sloc (N);
+
+ Lnn : array (1 .. Ndim) of Entity_Id;
+ Rnn : array (1 .. Ndim) of Entity_Id;
+ -- Entities used as subscripts on left and right sides
+
+ L_Index_Type : array (1 .. Ndim) of Entity_Id;
+ R_Index_Type : array (1 .. Ndim) of Entity_Id;
+ -- Left and right index types
+
+ Assign : Node_Id;
+
+ F_Or_L : Name_Id;
+ S_Or_P : Name_Id;
+
+ function Build_Step (J : Nat) return Node_Id;
+ -- The increment step for the index of the right-hand side is written
+ -- as an attribute reference (Succ or Pred). This function returns
+ -- the corresponding node, which is placed at the end of the loop body.
+
+ ----------------
+ -- Build_Step --
+ ----------------
+
+ function Build_Step (J : Nat) return Node_Id is
+ Step : Node_Id;
+ Lim : Name_Id;
+
+ begin
+ if Rev then
+ Lim := Name_First;
+ else
+ Lim := Name_Last;
+ end if;
+
+ Step :=
+ Make_Assignment_Statement (Loc,
+ Name => New_Occurrence_Of (Rnn (J), Loc),
+ Expression =>
+ Make_Attribute_Reference (Loc,
+ Prefix =>
+ New_Occurrence_Of (R_Index_Type (J), Loc),
+ Attribute_Name => S_Or_P,
+ Expressions => New_List (
+ New_Occurrence_Of (Rnn (J), Loc))));
+
+ -- Note that on the last iteration of the loop, the index is increased
+ -- (or decreased) past the corresponding bound. This is consistent with
+ -- the C semantics of the back-end, where such an off-by-one value on a
+ -- dead index variable is OK. However, in CodePeer mode this leads to
+ -- spurious warnings, and thus we place a guard around the attribute
+ -- reference. For obvious reasons we only do this for CodePeer.
+
+ if CodePeer_Mode then
+ Step :=
+ Make_If_Statement (Loc,
+ Condition =>
+ Make_Op_Ne (Loc,
+ Left_Opnd => New_Occurrence_Of (Lnn (J), Loc),
+ Right_Opnd =>
+ Make_Attribute_Reference (Loc,
+ Prefix => New_Occurrence_Of (L_Index_Type (J), Loc),
+ Attribute_Name => Lim)),
+ Then_Statements => New_List (Step));
+ end if;
+
+ return Step;
+ end Build_Step;
+
+ -- Start of processing for Expand_Assign_Array_Loop
+
+ begin
+ if Rev then
+ F_Or_L := Name_Last;
+ S_Or_P := Name_Pred;
+ else
+ F_Or_L := Name_First;
+ S_Or_P := Name_Succ;
+ end if;
+
+ -- Setup index types and subscript entities
+
+ declare
+ L_Index : Node_Id;
+ R_Index : Node_Id;
+
+ begin
+ L_Index := First_Index (L_Type);
+ R_Index := First_Index (R_Type);
+
+ for J in 1 .. Ndim loop
+ Lnn (J) := Make_Temporary (Loc, 'L');
+ Rnn (J) := Make_Temporary (Loc, 'R');
+
+ L_Index_Type (J) := Etype (L_Index);
+ R_Index_Type (J) := Etype (R_Index);
+
+ Next_Index (L_Index);
+ Next_Index (R_Index);
+ end loop;
+ end;
+
+ -- Now construct the assignment statement
+
+ declare
+ ExprL : constant List_Id := New_List;
+ ExprR : constant List_Id := New_List;
+
+ begin
+ for J in 1 .. Ndim loop
+ Append_To (ExprL, New_Occurrence_Of (Lnn (J), Loc));
+ Append_To (ExprR, New_Occurrence_Of (Rnn (J), Loc));
+ end loop;
+
+ Assign :=
+ Make_Assignment_Statement (Loc,
+ Name =>
+ Make_Indexed_Component (Loc,
+ Prefix => Duplicate_Subexpr (Larray, Name_Req => True),
+ Expressions => ExprL),
+ Expression =>
+ Make_Indexed_Component (Loc,
+ Prefix => Duplicate_Subexpr (Rarray, Name_Req => True),
+ Expressions => ExprR));
+
+ -- We set assignment OK, since there are some cases, e.g. in object
+ -- declarations, where we are actually assigning into a constant.
+ -- If there really is an illegality, it was caught long before now,
+ -- and was flagged when the original assignment was analyzed.
+
+ Set_Assignment_OK (Name (Assign));
+
+ -- Propagate the No_Ctrl_Actions flag to individual assignments
+
+ Set_No_Ctrl_Actions (Assign, No_Ctrl_Actions (N));
+ end;
+
+ -- Now construct the loop from the inside out, with the last subscript
+ -- varying most rapidly. Note that Assign is first the raw assignment
+ -- statement, and then subsequently the loop that wraps it up.
+
+ for J in reverse 1 .. Ndim loop
+ Assign :=
+ Make_Block_Statement (Loc,
+ Declarations => New_List (
+ Make_Object_Declaration (Loc,
+ Defining_Identifier => Rnn (J),
+ Object_Definition =>
+ New_Occurrence_Of (R_Index_Type (J), Loc),
+ Expression =>
+ Make_Attribute_Reference (Loc,
+ Prefix => New_Occurrence_Of (R_Index_Type (J), Loc),
+ Attribute_Name => F_Or_L))),
+
+ Handled_Statement_Sequence =>
+ Make_Handled_Sequence_Of_Statements (Loc,
+ Statements => New_List (
+ Make_Implicit_Loop_Statement (N,
+ Iteration_Scheme =>
+ Make_Iteration_Scheme (Loc,
+ Loop_Parameter_Specification =>
+ Make_Loop_Parameter_Specification (Loc,
+ Defining_Identifier => Lnn (J),
+ Reverse_Present => Rev,
+ Discrete_Subtype_Definition =>
+ New_Reference_To (L_Index_Type (J), Loc))),
+
+ Statements => New_List (Assign, Build_Step (J))))));
+ end loop;
+
+ return Assign;
+ end Expand_Assign_Array_Loop;
+
+ --------------------------
+ -- Expand_Assign_Record --
+ --------------------------
+
+ procedure Expand_Assign_Record (N : Node_Id) is
+ Lhs : constant Node_Id := Name (N);
+ Rhs : Node_Id := Expression (N);
+ L_Typ : constant Entity_Id := Base_Type (Etype (Lhs));
+
+ begin
+ -- If change of representation, then extract the real right hand side
+ -- from the type conversion, and proceed with component-wise assignment,
+ -- since the two types are not the same as far as the back end is
+ -- concerned.
+
+ if Change_Of_Representation (N) then
+ Rhs := Expression (Rhs);
+
+ -- If this may be a case of a large bit aligned component, then proceed
+ -- with component-wise assignment, to avoid possible clobbering of other
+ -- components sharing bits in the first or last byte of the component to
+ -- be assigned.
+
+ elsif Possible_Bit_Aligned_Component (Lhs)
+ or
+ Possible_Bit_Aligned_Component (Rhs)
+ then
+ null;
+
+ -- If we have a tagged type that has a complete record representation
+ -- clause, we must do we must do component-wise assignments, since child
+ -- types may have used gaps for their components, and we might be
+ -- dealing with a view conversion.
+
+ elsif Is_Fully_Repped_Tagged_Type (L_Typ) then
+ null;
+
+ -- If neither condition met, then nothing special to do, the back end
+ -- can handle assignment of the entire component as a single entity.
+
+ else
+ return;
+ end if;
+
+ -- At this stage we know that we must do a component wise assignment
+
+ declare
+ Loc : constant Source_Ptr := Sloc (N);
+ R_Typ : constant Entity_Id := Base_Type (Etype (Rhs));
+ Decl : constant Node_Id := Declaration_Node (R_Typ);
+ RDef : Node_Id;
+ F : Entity_Id;
+
+ function Find_Component
+ (Typ : Entity_Id;
+ Comp : Entity_Id) return Entity_Id;
+ -- Find the component with the given name in the underlying record
+ -- declaration for Typ. We need to use the actual entity because the
+ -- type may be private and resolution by identifier alone would fail.
+
+ function Make_Component_List_Assign
+ (CL : Node_Id;
+ U_U : Boolean := False) return List_Id;
+ -- Returns a sequence of statements to assign the components that
+ -- are referenced in the given component list. The flag U_U is
+ -- used to force the usage of the inferred value of the variant
+ -- part expression as the switch for the generated case statement.
+
+ function Make_Field_Assign
+ (C : Entity_Id;
+ U_U : Boolean := False) return Node_Id;
+ -- Given C, the entity for a discriminant or component, build an
+ -- assignment for the corresponding field values. The flag U_U
+ -- signals the presence of an Unchecked_Union and forces the usage
+ -- of the inferred discriminant value of C as the right hand side
+ -- of the assignment.
+
+ function Make_Field_Assigns (CI : List_Id) return List_Id;
+ -- Given CI, a component items list, construct series of statements
+ -- for fieldwise assignment of the corresponding components.
+
+ --------------------
+ -- Find_Component --
+ --------------------
+
+ function Find_Component
+ (Typ : Entity_Id;
+ Comp : Entity_Id) return Entity_Id
+ is
+ Utyp : constant Entity_Id := Underlying_Type (Typ);
+ C : Entity_Id;
+
+ begin
+ C := First_Entity (Utyp);
+ while Present (C) loop
+ if Chars (C) = Chars (Comp) then
+ return C;
+ end if;
+
+ Next_Entity (C);
+ end loop;
+
+ raise Program_Error;
+ end Find_Component;
+
+ --------------------------------
+ -- Make_Component_List_Assign --
+ --------------------------------
+
+ function Make_Component_List_Assign
+ (CL : Node_Id;
+ U_U : Boolean := False) return List_Id
+ is
+ CI : constant List_Id := Component_Items (CL);
+ VP : constant Node_Id := Variant_Part (CL);
+
+ Alts : List_Id;
+ DC : Node_Id;
+ DCH : List_Id;
+ Expr : Node_Id;
+ Result : List_Id;
+ V : Node_Id;
+
+ begin
+ Result := Make_Field_Assigns (CI);
+
+ if Present (VP) then
+ V := First_Non_Pragma (Variants (VP));
+ Alts := New_List;
+ while Present (V) loop
+ DCH := New_List;
+ DC := First (Discrete_Choices (V));
+ while Present (DC) loop
+ Append_To (DCH, New_Copy_Tree (DC));
+ Next (DC);
+ end loop;
+
+ Append_To (Alts,
+ Make_Case_Statement_Alternative (Loc,
+ Discrete_Choices => DCH,
+ Statements =>
+ Make_Component_List_Assign (Component_List (V))));
+ Next_Non_Pragma (V);
+ end loop;
+
+ -- If we have an Unchecked_Union, use the value of the inferred
+ -- discriminant of the variant part expression as the switch
+ -- for the case statement. The case statement may later be
+ -- folded.
+
+ if U_U then
+ Expr :=
+ New_Copy (Get_Discriminant_Value (
+ Entity (Name (VP)),
+ Etype (Rhs),
+ Discriminant_Constraint (Etype (Rhs))));
+ else
+ Expr :=
+ Make_Selected_Component (Loc,
+ Prefix => Duplicate_Subexpr (Rhs),
+ Selector_Name =>
+ Make_Identifier (Loc, Chars (Name (VP))));
+ end if;
+
+ Append_To (Result,
+ Make_Case_Statement (Loc,
+ Expression => Expr,
+ Alternatives => Alts));
+ end if;
+
+ return Result;
+ end Make_Component_List_Assign;
+
+ -----------------------
+ -- Make_Field_Assign --
+ -----------------------
+
+ function Make_Field_Assign
+ (C : Entity_Id;
+ U_U : Boolean := False) return Node_Id
+ is
+ A : Node_Id;
+ Expr : Node_Id;
+
+ begin
+ -- In the case of an Unchecked_Union, use the discriminant
+ -- constraint value as on the right hand side of the assignment.
+
+ if U_U then
+ Expr :=
+ New_Copy (Get_Discriminant_Value (C,
+ Etype (Rhs),
+ Discriminant_Constraint (Etype (Rhs))));
+ else
+ Expr :=
+ Make_Selected_Component (Loc,
+ Prefix => Duplicate_Subexpr (Rhs),
+ Selector_Name => New_Occurrence_Of (C, Loc));
+ end if;
+
+ A :=
+ Make_Assignment_Statement (Loc,
+ Name =>
+ Make_Selected_Component (Loc,
+ Prefix => Duplicate_Subexpr (Lhs),
+ Selector_Name =>
+ New_Occurrence_Of (Find_Component (L_Typ, C), Loc)),
+ Expression => Expr);
+
+ -- Set Assignment_OK, so discriminants can be assigned
+
+ Set_Assignment_OK (Name (A), True);
+
+ if Componentwise_Assignment (N)
+ and then Nkind (Name (A)) = N_Selected_Component
+ and then Chars (Selector_Name (Name (A))) = Name_uParent
+ then
+ Set_Componentwise_Assignment (A);
+ end if;
+
+ return A;
+ end Make_Field_Assign;
+
+ ------------------------
+ -- Make_Field_Assigns --
+ ------------------------
+
+ function Make_Field_Assigns (CI : List_Id) return List_Id is
+ Item : Node_Id;
+ Result : List_Id;
+
+ begin
+ Item := First (CI);
+ Result := New_List;
+
+ while Present (Item) loop
+
+ -- Look for components, but exclude _tag field assignment if
+ -- the special Componentwise_Assignment flag is set.
+
+ if Nkind (Item) = N_Component_Declaration
+ and then not (Is_Tag (Defining_Identifier (Item))
+ and then Componentwise_Assignment (N))
+ then
+ Append_To
+ (Result, Make_Field_Assign (Defining_Identifier (Item)));
+ end if;
+
+ Next (Item);
+ end loop;
+
+ return Result;
+ end Make_Field_Assigns;
+
+ -- Start of processing for Expand_Assign_Record
+
+ begin
+ -- Note that we use the base types for this processing. This results
+ -- in some extra work in the constrained case, but the change of
+ -- representation case is so unusual that it is not worth the effort.
+
+ -- First copy the discriminants. This is done unconditionally. It
+ -- is required in the unconstrained left side case, and also in the
+ -- case where this assignment was constructed during the expansion
+ -- of a type conversion (since initialization of discriminants is
+ -- suppressed in this case). It is unnecessary but harmless in
+ -- other cases.
+
+ if Has_Discriminants (L_Typ) then
+ F := First_Discriminant (R_Typ);
+ while Present (F) loop
+
+ -- If we are expanding the initialization of a derived record
+ -- that constrains or renames discriminants of the parent, we
+ -- must use the corresponding discriminant in the parent.
+
+ declare
+ CF : Entity_Id;
+
+ begin
+ if Inside_Init_Proc
+ and then Present (Corresponding_Discriminant (F))
+ then
+ CF := Corresponding_Discriminant (F);
+ else
+ CF := F;
+ end if;
+
+ if Is_Unchecked_Union (Base_Type (R_Typ)) then
+
+ -- Within an initialization procedure this is the
+ -- assignment to an unchecked union component, in which
+ -- case there is no discriminant to initialize.
+
+ if Inside_Init_Proc then
+ null;
+
+ else
+ -- The assignment is part of a conversion from a
+ -- derived unchecked union type with an inferable
+ -- discriminant, to a parent type.
+
+ Insert_Action (N, Make_Field_Assign (CF, True));
+ end if;
+
+ else
+ Insert_Action (N, Make_Field_Assign (CF));
+ end if;
+
+ Next_Discriminant (F);
+ end;
+ end loop;
+ end if;
+
+ -- We know the underlying type is a record, but its current view
+ -- may be private. We must retrieve the usable record declaration.
+
+ if Nkind_In (Decl, N_Private_Type_Declaration,
+ N_Private_Extension_Declaration)
+ and then Present (Full_View (R_Typ))
+ then
+ RDef := Type_Definition (Declaration_Node (Full_View (R_Typ)));
+ else
+ RDef := Type_Definition (Decl);
+ end if;
+
+ if Nkind (RDef) = N_Derived_Type_Definition then
+ RDef := Record_Extension_Part (RDef);
+ end if;
+
+ if Nkind (RDef) = N_Record_Definition
+ and then Present (Component_List (RDef))
+ then
+ if Is_Unchecked_Union (R_Typ) then
+ Insert_Actions (N,
+ Make_Component_List_Assign (Component_List (RDef), True));
+ else
+ Insert_Actions
+ (N, Make_Component_List_Assign (Component_List (RDef)));
+ end if;
+
+ Rewrite (N, Make_Null_Statement (Loc));
+ end if;
+ end;
+ end Expand_Assign_Record;
+
+ ----------------------------------
+ -- Expand_Loop_Entry_Attributes --
+ ----------------------------------
+
+ procedure Expand_Loop_Entry_Attributes (N : Node_Id) is
+ procedure Build_Conditional_Block
+ (Loc : Source_Ptr;
+ Cond : Node_Id;
+ Stmt : Node_Id;
+ If_Stmt : out Node_Id;
+ Blk_Stmt : out Node_Id);
+ -- Create a block Blk_Stmt with an empty declarative list and a single
+ -- statement Stmt. The block is encased in an if statement If_Stmt with
+ -- condition Cond. If_Stmt is Empty when there is no condition provided.
+
+ function Is_Array_Iteration (N : Node_Id) return Boolean;
+ -- Determine whether loop statement N denotes an Ada 2012 iteration over
+ -- an array object.
+
+ -----------------------------
+ -- Build_Conditional_Block --
+ -----------------------------
+
+ procedure Build_Conditional_Block
+ (Loc : Source_Ptr;
+ Cond : Node_Id;
+ Stmt : Node_Id;
+ If_Stmt : out Node_Id;
+ Blk_Stmt : out Node_Id)
+ is
+ begin
+ Blk_Stmt :=
+ Make_Block_Statement (Loc,
+ Declarations => New_List,
+ Handled_Statement_Sequence =>
+ Make_Handled_Sequence_Of_Statements (Loc,
+ Statements => New_List (Stmt)));
+
+ if Present (Cond) then
+ If_Stmt :=
+ Make_If_Statement (Loc,
+ Condition => Cond,
+ Then_Statements => New_List (Blk_Stmt));
+ else
+ If_Stmt := Empty;
+ end if;
+ end Build_Conditional_Block;
+
+ ------------------------
+ -- Is_Array_Iteration --
+ ------------------------
+
+ function Is_Array_Iteration (N : Node_Id) return Boolean is
+ Stmt : constant Node_Id := Original_Node (N);
+ Iter : Node_Id;
+
+ begin
+ if Nkind (Stmt) = N_Loop_Statement
+ and then Present (Iteration_Scheme (Stmt))
+ and then Present (Iterator_Specification (Iteration_Scheme (Stmt)))
+ then
+ Iter := Iterator_Specification (Iteration_Scheme (Stmt));
+
+ return
+ Of_Present (Iter)
+ and then Is_Array_Type (Etype (Name (Iter)));
+ end if;
+
+ return False;
+ end Is_Array_Iteration;
+
+ -- Local variables
+
+ Loc : constant Source_Ptr := Sloc (N);
+ Loop_Id : constant Entity_Id := Identifier (N);
+ Scheme : constant Node_Id := Iteration_Scheme (N);
+ Blk : Node_Id;
+ LE : Node_Id;
+ LE_Elmt : Elmt_Id;
+ Result : Node_Id;
+ Temp : Entity_Id;
+ Typ : Entity_Id;
+
+ -- Start of processing for Expand_Loop_Entry_Attributes
+
+ begin
+ -- The loop will never execute after it has been expanded, no point in
+ -- processing it.
+
+ if Is_Null_Loop (N) then
+ return;
+
+ -- A loop without an identifier cannot be referenced in 'Loop_Entry
+
+ elsif No (Loop_Id) then
+ return;
+
+ -- The loop is not subject to 'Loop_Entry
+
+ elsif No (Loop_Entry_Attributes (Entity (Loop_Id))) then
+ return;
+
+ -- Step 1: Loop transformations
+
+ -- While loops are transformed into:
+
+ -- if <Condition> then
+ -- declare
+ -- Temp1 : constant <type of Pref1> := <Pref1>;
+ -- . . .
+ -- TempN : constant <type of PrefN> := <PrefN>;
+ -- begin
+ -- loop
+ -- <original source statements with attribute rewrites>
+ -- exit when not <Condition>;
+ -- end loop;
+ -- end;
+ -- end if;
+
+ -- Note that loops over iterators and containers are already converted
+ -- into while loops.
+
+ elsif Present (Condition (Scheme)) then
+ declare
+ Cond : constant Node_Id := Condition (Scheme);
+
+ begin
+ -- Transform the original while loop into an infinite loop where
+ -- the last statement checks the negated condition. This placement
+ -- ensures that the condition will not be evaluated twice on the
+ -- first iteration.
+
+ -- Generate:
+ -- exit when not <Cond>:
+
+ Append_To (Statements (N),
+ Make_Exit_Statement (Loc,
+ Condition => Make_Op_Not (Loc, New_Copy_Tree (Cond))));
+
+ Build_Conditional_Block (Loc,
+ Cond => Relocate_Node (Cond),
+ Stmt => Relocate_Node (N),
+ If_Stmt => Result,
+ Blk_Stmt => Blk);
+ end;
+
+ -- Ada 2012 iteration over an array is transformed into:
+
+ -- if <Array_Nam>'Length (1) > 0
+ -- and then <Array_Nam>'Length (N) > 0
+ -- then
+ -- declare
+ -- Temp1 : constant <type of Pref1> := <Pref1>;
+ -- . . .
+ -- TempN : constant <type of PrefN> := <PrefN>;
+ -- begin
+ -- for X in ... loop -- multiple loops depending on dims
+ -- <original source statements with attribute rewrites>
+ -- end loop;
+ -- end;
+ -- end if;
+
+ elsif Is_Array_Iteration (N) then
+ declare
+ Array_Nam : constant Entity_Id :=
+ Entity (Name (Iterator_Specification
+ (Iteration_Scheme (Original_Node (N)))));
+ Num_Dims : constant Pos :=
+ Number_Dimensions (Etype (Array_Nam));
+ Cond : Node_Id := Empty;
+ Check : Node_Id;
+ Top_Loop : Node_Id;
+
+ begin
+ -- Generate a check which determines whether all dimensions of
+ -- the array are non-null.
+
+ for Dim in 1 .. Num_Dims loop
+ Check :=
+ Make_Op_Gt (Loc,
+ Left_Opnd =>
+ Make_Attribute_Reference (Loc,
+ Prefix => New_Reference_To (Array_Nam, Loc),
+ Attribute_Name => Name_Length,
+ Expressions => New_List (
+ Make_Integer_Literal (Loc, Dim))),
+ Right_Opnd =>
+ Make_Integer_Literal (Loc, 0));
+
+ if No (Cond) then
+ Cond := Check;
+ else
+ Cond :=
+ Make_And_Then (Loc,
+ Left_Opnd => Cond,
+ Right_Opnd => Check);
+ end if;
+ end loop;
+
+ Top_Loop := Relocate_Node (N);
+ Set_Analyzed (Top_Loop);
+
+ Build_Conditional_Block (Loc,
+ Cond => Cond,
+ Stmt => Top_Loop,
+ If_Stmt => Result,
+ Blk_Stmt => Blk);
+ end;
+
+ -- For loops are transformed into:
+
+ -- if <Low> <= <High> then
+ -- declare
+ -- Temp1 : constant <type of Pref1> := <Pref1>;
+ -- . . .
+ -- TempN : constant <type of PrefN> := <PrefN>;
+ -- begin
+ -- for <Def_Id> in <Low> .. <High> loop
+ -- <original source statements with attribute rewrites>
+ -- end loop;
+ -- end;
+ -- end if;
+
+ elsif Present (Loop_Parameter_Specification (Scheme)) then
+ declare
+ Loop_Spec : constant Node_Id :=
+ Loop_Parameter_Specification (Scheme);
+ Cond : Node_Id;
+ Subt_Def : Node_Id;
+
+ begin
+ Subt_Def := Discrete_Subtype_Definition (Loop_Spec);
+
+ -- When the loop iterates over a subtype indication with a range,
+ -- use the low and high bounds of the subtype itself.
+
+ if Nkind (Subt_Def) = N_Subtype_Indication then
+ Subt_Def := Scalar_Range (Etype (Subt_Def));
+ end if;
+
+ pragma Assert (Nkind (Subt_Def) = N_Range);
+
+ -- Generate
+ -- Low <= High
+
+ Cond :=
+ Make_Op_Le (Loc,
+ Left_Opnd => New_Copy_Tree (Low_Bound (Subt_Def)),
+ Right_Opnd => New_Copy_Tree (High_Bound (Subt_Def)));
+
+ Build_Conditional_Block (Loc,
+ Cond => Cond,
+ Stmt => Relocate_Node (N),
+ If_Stmt => Result,
+ Blk_Stmt => Blk);
+ end;
+
+ -- Infinite loops are transformed into:
+
+ -- declare
+ -- Temp1 : constant <type of Pref1> := <Pref1>;
+ -- . . .
+ -- TempN : constant <type of PrefN> := <PrefN>;
+ -- begin
+ -- loop
+ -- <original source statements with attribute rewrites>
+ -- end loop;
+ -- end;
+
+ else
+ Build_Conditional_Block (Loc,
+ Cond => Empty,
+ Stmt => Relocate_Node (N),
+ If_Stmt => Result,
+ Blk_Stmt => Blk);
+
+ Result := Blk;
+ end if;
+
+ -- Step 2: Loop_Entry attribute transformations
+
+ -- At this point the various loops have been augmented to contain a
+ -- block. Populate the declarative list of the block with constants
+ -- which store the value of their relative prefixes at the point of
+ -- entry in the loop.
+
+ LE_Elmt := First_Elmt (Loop_Entry_Attributes (Entity (Loop_Id)));
+ while Present (LE_Elmt) loop
+ LE := Node (LE_Elmt);
+ Typ := Etype (Prefix (LE));
+
+ -- Declare a constant to capture the value of the previx of each
+ -- Loop_Entry attribute.
+
+ -- Generate:
+ -- Temp : constant <type of Pref> := <Pref>;
+
+ Temp := Make_Temporary (Loc, 'P');
+
+ Append_To (Declarations (Blk),
+ Make_Object_Declaration (Loc,
+ Defining_Identifier => Temp,
+ Constant_Present => True,
+ Object_Definition => New_Reference_To (Typ, Loc),
+ Expression => Relocate_Node (Prefix (LE))));
+
+ -- Perform minor decoration as this information will be needed for
+ -- the creation of index checks (if applicable).
+
+ Set_Ekind (Temp, E_Constant);
+ Set_Etype (Temp, Typ);
+
+ -- Replace the original attribute with a reference to the constant
+
+ Rewrite (LE, New_Reference_To (Temp, Loc));
+ Set_Etype (LE, Typ);
+
+ -- Analysis converts attribute references of the following form
+
+ -- Prefix'Loop_Entry (Expr)
+ -- Prefix'Loop_Entry (Expr1, Expr2, ... ExprN)
+
+ -- into indexed components for error detection purposes. Generate
+ -- index checks now that 'Loop_Entry has been properly expanded.
+
+ if Nkind (Parent (LE)) = N_Indexed_Component then
+ Generate_Index_Checks (Parent (LE));
+ end if;
+
+ Next_Elmt (LE_Elmt);
+ end loop;
+
+ -- Destroy the list of Loop_Entry attributes to prevent the infinite
+ -- expansion when analyzing and expanding the newly generated loops.
+
+ Set_Loop_Entry_Attributes (Entity (Loop_Id), No_Elist);
+
+ Rewrite (N, Result);
+ Analyze (N);
+ end Expand_Loop_Entry_Attributes;
+
+ -----------------------------------
+ -- Expand_N_Assignment_Statement --
+ -----------------------------------
+
+ -- This procedure implements various cases where an assignment statement
+ -- cannot just be passed on to the back end in untransformed state.
+
+ procedure Expand_N_Assignment_Statement (N : Node_Id) is
+ Loc : constant Source_Ptr := Sloc (N);
+ Crep : constant Boolean := Change_Of_Representation (N);
+ Lhs : constant Node_Id := Name (N);
+ Rhs : constant Node_Id := Expression (N);
+ Typ : constant Entity_Id := Underlying_Type (Etype (Lhs));
+ Exp : Node_Id;
+
+ begin
+ -- Special case to check right away, if the Componentwise_Assignment
+ -- flag is set, this is a reanalysis from the expansion of the primitive
+ -- assignment procedure for a tagged type, and all we need to do is to
+ -- expand to assignment of components, because otherwise, we would get
+ -- infinite recursion (since this looks like a tagged assignment which
+ -- would normally try to *call* the primitive assignment procedure).
+
+ if Componentwise_Assignment (N) then
+ Expand_Assign_Record (N);
+ return;
+ end if;
+
+ -- Defend against invalid subscripts on left side if we are in standard
+ -- validity checking mode. No need to do this if we are checking all
+ -- subscripts.
+
+ -- Note that we do this right away, because there are some early return
+ -- paths in this procedure, and this is required on all paths.
+
+ if Validity_Checks_On
+ and then Validity_Check_Default
+ and then not Validity_Check_Subscripts
+ then
+ Check_Valid_Lvalue_Subscripts (Lhs);
+ end if;
+
+ -- Ada 2005 (AI-327): Handle assignment to priority of protected object
+
+ -- Rewrite an assignment to X'Priority into a run-time call
+
+ -- For example: X'Priority := New_Prio_Expr;
+ -- ...is expanded into Set_Ceiling (X._Object, New_Prio_Expr);
+
+ -- Note that although X'Priority is notionally an object, it is quite
+ -- deliberately not defined as an aliased object in the RM. This means
+ -- that it works fine to rewrite it as a call, without having to worry
+ -- about complications that would other arise from X'Priority'Access,
+ -- which is illegal, because of the lack of aliasing.
+
+ if Ada_Version >= Ada_2005 then
+ declare
+ Call : Node_Id;
+ Conctyp : Entity_Id;
+ Ent : Entity_Id;
+ Subprg : Entity_Id;
+ RT_Subprg_Name : Node_Id;
+
+ begin
+ -- Handle chains of renamings
+
+ Ent := Name (N);
+ while Nkind (Ent) in N_Has_Entity
+ and then Present (Entity (Ent))
+ and then Present (Renamed_Object (Entity (Ent)))
+ loop
+ Ent := Renamed_Object (Entity (Ent));
+ end loop;
+
+ -- The attribute Priority applied to protected objects has been
+ -- previously expanded into a call to the Get_Ceiling run-time
+ -- subprogram.
+
+ if Nkind (Ent) = N_Function_Call
+ and then (Entity (Name (Ent)) = RTE (RE_Get_Ceiling)
+ or else
+ Entity (Name (Ent)) = RTE (RO_PE_Get_Ceiling))
+ then
+ -- Look for the enclosing concurrent type
+
+ Conctyp := Current_Scope;
+ while not Is_Concurrent_Type (Conctyp) loop
+ Conctyp := Scope (Conctyp);
+ end loop;
+
+ pragma Assert (Is_Protected_Type (Conctyp));
+
+ -- Generate the first actual of the call
+
+ Subprg := Current_Scope;
+ while not Present (Protected_Body_Subprogram (Subprg)) loop
+ Subprg := Scope (Subprg);
+ end loop;
+
+ -- Select the appropriate run-time call
+
+ if Number_Entries (Conctyp) = 0 then
+ RT_Subprg_Name :=
+ New_Reference_To (RTE (RE_Set_Ceiling), Loc);
+ else
+ RT_Subprg_Name :=
+ New_Reference_To (RTE (RO_PE_Set_Ceiling), Loc);
+ end if;
+
+ Call :=
+ Make_Procedure_Call_Statement (Loc,
+ Name => RT_Subprg_Name,
+ Parameter_Associations => New_List (
+ New_Copy_Tree (First (Parameter_Associations (Ent))),
+ Relocate_Node (Expression (N))));
+
+ Rewrite (N, Call);
+ Analyze (N);
+ return;
+ end if;
+ end;
+ end if;
+
+ -- Deal with assignment checks unless suppressed
+
+ if not Suppress_Assignment_Checks (N) then
+
+ -- First deal with generation of range check if required
+
+ if Do_Range_Check (Rhs) then
+ Set_Do_Range_Check (Rhs, False);
+ Generate_Range_Check (Rhs, Typ, CE_Range_Check_Failed);
+ end if;
+
+ -- Then generate predicate check if required
+
+ Apply_Predicate_Check (Rhs, Typ);
+ end if;
+
+ -- Check for a special case where a high level transformation is
+ -- required. If we have either of:
+
+ -- P.field := rhs;
+ -- P (sub) := rhs;
+
+ -- where P is a reference to a bit packed array, then we have to unwind
+ -- the assignment. The exact meaning of being a reference to a bit
+ -- packed array is as follows:
+
+ -- An indexed component whose prefix is a bit packed array is a
+ -- reference to a bit packed array.
+
+ -- An indexed component or selected component whose prefix is a
+ -- reference to a bit packed array is itself a reference ot a
+ -- bit packed array.
+
+ -- The required transformation is
+
+ -- Tnn : prefix_type := P;
+ -- Tnn.field := rhs;
+ -- P := Tnn;
+
+ -- or
+
+ -- Tnn : prefix_type := P;
+ -- Tnn (subscr) := rhs;
+ -- P := Tnn;
+
+ -- Since P is going to be evaluated more than once, any subscripts
+ -- in P must have their evaluation forced.
+
+ if Nkind_In (Lhs, N_Indexed_Component, N_Selected_Component)
+ and then Is_Ref_To_Bit_Packed_Array (Prefix (Lhs))
+ then
+ declare
+ BPAR_Expr : constant Node_Id := Relocate_Node (Prefix (Lhs));
+ BPAR_Typ : constant Entity_Id := Etype (BPAR_Expr);
+ Tnn : constant Entity_Id :=
+ Make_Temporary (Loc, 'T', BPAR_Expr);
+
+ begin
+ -- Insert the post assignment first, because we want to copy the
+ -- BPAR_Expr tree before it gets analyzed in the context of the
+ -- pre assignment. Note that we do not analyze the post assignment
+ -- yet (we cannot till we have completed the analysis of the pre
+ -- assignment). As usual, the analysis of this post assignment
+ -- will happen on its own when we "run into" it after finishing
+ -- the current assignment.
+
+ Insert_After (N,
+ Make_Assignment_Statement (Loc,
+ Name => New_Copy_Tree (BPAR_Expr),
+ Expression => New_Occurrence_Of (Tnn, Loc)));
+
+ -- At this stage BPAR_Expr is a reference to a bit packed array
+ -- where the reference was not expanded in the original tree,
+ -- since it was on the left side of an assignment. But in the
+ -- pre-assignment statement (the object definition), BPAR_Expr
+ -- will end up on the right hand side, and must be reexpanded. To
+ -- achieve this, we reset the analyzed flag of all selected and
+ -- indexed components down to the actual indexed component for
+ -- the packed array.
+
+ Exp := BPAR_Expr;
+ loop
+ Set_Analyzed (Exp, False);
+
+ if Nkind_In
+ (Exp, N_Selected_Component, N_Indexed_Component)
+ then
+ Exp := Prefix (Exp);
+ else
+ exit;
+ end if;
+ end loop;
+
+ -- Now we can insert and analyze the pre-assignment
+
+ -- If the right-hand side requires a transient scope, it has
+ -- already been placed on the stack. However, the declaration is
+ -- inserted in the tree outside of this scope, and must reflect
+ -- the proper scope for its variable. This awkward bit is forced
+ -- by the stricter scope discipline imposed by GCC 2.97.
+
+ declare
+ Uses_Transient_Scope : constant Boolean :=
+ Scope_Is_Transient
+ and then N = Node_To_Be_Wrapped;
+
+ begin
+ if Uses_Transient_Scope then
+ Push_Scope (Scope (Current_Scope));
+ end if;
+
+ Insert_Before_And_Analyze (N,
+ Make_Object_Declaration (Loc,
+ Defining_Identifier => Tnn,
+ Object_Definition => New_Occurrence_Of (BPAR_Typ, Loc),
+ Expression => BPAR_Expr));
+
+ if Uses_Transient_Scope then
+ Pop_Scope;
+ end if;
+ end;
+
+ -- Now fix up the original assignment and continue processing
+
+ Rewrite (Prefix (Lhs),
+ New_Occurrence_Of (Tnn, Loc));
+
+ -- We do not need to reanalyze that assignment, and we do not need
+ -- to worry about references to the temporary, but we do need to
+ -- make sure that the temporary is not marked as a true constant
+ -- since we now have a generated assignment to it!
+
+ Set_Is_True_Constant (Tnn, False);
+ end;
+ end if;
+
+ -- When we have the appropriate type of aggregate in the expression (it
+ -- has been determined during analysis of the aggregate by setting the
+ -- delay flag), let's perform in place assignment and thus avoid
+ -- creating a temporary.
+
+ if Is_Delayed_Aggregate (Rhs) then
+ Convert_Aggr_In_Assignment (N);
+ Rewrite (N, Make_Null_Statement (Loc));
+ Analyze (N);
+ return;
+ end if;
+
+ -- Apply discriminant check if required. If Lhs is an access type to a
+ -- designated type with discriminants, we must always check. If the
+ -- type has unknown discriminants, more elaborate processing below.
+
+ if Has_Discriminants (Etype (Lhs))
+ and then not Has_Unknown_Discriminants (Etype (Lhs))
+ then
+ -- Skip discriminant check if change of representation. Will be
+ -- done when the change of representation is expanded out.
+
+ if not Crep then
+ Apply_Discriminant_Check (Rhs, Etype (Lhs), Lhs);
+ end if;
+
+ -- If the type is private without discriminants, and the full type
+ -- has discriminants (necessarily with defaults) a check may still be
+ -- necessary if the Lhs is aliased. The private discriminants must be
+ -- visible to build the discriminant constraints.
+
+ -- Only an explicit dereference that comes from source indicates
+ -- aliasing. Access to formals of protected operations and entries
+ -- create dereferences but are not semantic aliasings.
+
+ elsif Is_Private_Type (Etype (Lhs))
+ and then Has_Discriminants (Typ)
+ and then Nkind (Lhs) = N_Explicit_Dereference
+ and then Comes_From_Source (Lhs)
+ then
+ declare
+ Lt : constant Entity_Id := Etype (Lhs);
+ Ubt : Entity_Id := Base_Type (Typ);
+
+ begin
+ -- In the case of an expander-generated record subtype whose base
+ -- type still appears private, Typ will have been set to that
+ -- private type rather than the underlying record type (because
+ -- Underlying type will have returned the record subtype), so it's
+ -- necessary to apply Underlying_Type again to the base type to
+ -- get the record type we need for the discriminant check. Such
+ -- subtypes can be created for assignments in certain cases, such
+ -- as within an instantiation passed this kind of private type.
+ -- It would be good to avoid this special test, but making changes
+ -- to prevent this odd form of record subtype seems difficult. ???
+
+ if Is_Private_Type (Ubt) then
+ Ubt := Underlying_Type (Ubt);
+ end if;
+
+ Set_Etype (Lhs, Ubt);
+ Rewrite (Rhs, OK_Convert_To (Base_Type (Ubt), Rhs));
+ Apply_Discriminant_Check (Rhs, Ubt, Lhs);
+ Set_Etype (Lhs, Lt);
+ end;
+
+ -- If the Lhs has a private type with unknown discriminants, it
+ -- may have a full view with discriminants, but those are nameable
+ -- only in the underlying type, so convert the Rhs to it before
+ -- potential checking.
+
+ elsif Has_Unknown_Discriminants (Base_Type (Etype (Lhs)))
+ and then Has_Discriminants (Typ)
+ then
+ Rewrite (Rhs, OK_Convert_To (Base_Type (Typ), Rhs));
+ Apply_Discriminant_Check (Rhs, Typ, Lhs);
+
+ -- In the access type case, we need the same discriminant check, and
+ -- also range checks if we have an access to constrained array.
+
+ elsif Is_Access_Type (Etype (Lhs))
+ and then Is_Constrained (Designated_Type (Etype (Lhs)))
+ then
+ if Has_Discriminants (Designated_Type (Etype (Lhs))) then
+
+ -- Skip discriminant check if change of representation. Will be
+ -- done when the change of representation is expanded out.
+
+ if not Crep then
+ Apply_Discriminant_Check (Rhs, Etype (Lhs));
+ end if;
+
+ elsif Is_Array_Type (Designated_Type (Etype (Lhs))) then
+ Apply_Range_Check (Rhs, Etype (Lhs));
+
+ if Is_Constrained (Etype (Lhs)) then
+ Apply_Length_Check (Rhs, Etype (Lhs));
+ end if;
+
+ if Nkind (Rhs) = N_Allocator then
+ declare
+ Target_Typ : constant Entity_Id := Etype (Expression (Rhs));
+ C_Es : Check_Result;
+
+ begin
+ C_Es :=
+ Get_Range_Checks
+ (Lhs,
+ Target_Typ,
+ Etype (Designated_Type (Etype (Lhs))));
+
+ Insert_Range_Checks
+ (C_Es,
+ N,
+ Target_Typ,
+ Sloc (Lhs),
+ Lhs);
+ end;
+ end if;
+ end if;
+
+ -- Apply range check for access type case
+
+ elsif Is_Access_Type (Etype (Lhs))
+ and then Nkind (Rhs) = N_Allocator
+ and then Nkind (Expression (Rhs)) = N_Qualified_Expression
+ then
+ Analyze_And_Resolve (Expression (Rhs));
+ Apply_Range_Check
+ (Expression (Rhs), Designated_Type (Etype (Lhs)));
+ end if;
+
+ -- Ada 2005 (AI-231): Generate the run-time check
+
+ if Is_Access_Type (Typ)
+ and then Can_Never_Be_Null (Etype (Lhs))
+ and then not Can_Never_Be_Null (Etype (Rhs))
+ then
+ Apply_Constraint_Check (Rhs, Etype (Lhs));
+ end if;
+
+ -- Ada 2012 (AI05-148): Update current accessibility level if Rhs is a
+ -- stand-alone obj of an anonymous access type.
+
+ if Is_Access_Type (Typ)
+ and then Is_Entity_Name (Lhs)
+ and then Present (Effective_Extra_Accessibility (Entity (Lhs))) then
+ declare
+ function Lhs_Entity return Entity_Id;
+ -- Look through renames to find the underlying entity.
+ -- For assignment to a rename, we don't care about the
+ -- Enclosing_Dynamic_Scope of the rename declaration.
+
+ ----------------
+ -- Lhs_Entity --
+ ----------------
+
+ function Lhs_Entity return Entity_Id is
+ Result : Entity_Id := Entity (Lhs);
+
+ begin
+ while Present (Renamed_Object (Result)) loop
+
+ -- Renamed_Object must return an Entity_Name here
+ -- because of preceding "Present (E_E_A (...))" test.
+
+ Result := Entity (Renamed_Object (Result));
+ end loop;
+
+ return Result;
+ end Lhs_Entity;
+
+ -- Local Declarations
+
+ Access_Check : constant Node_Id :=
+ Make_Raise_Program_Error (Loc,
+ Condition =>
+ Make_Op_Gt (Loc,
+ Left_Opnd =>
+ Dynamic_Accessibility_Level (Rhs),
+ Right_Opnd =>
+ Make_Integer_Literal (Loc,
+ Intval =>
+ Scope_Depth
+ (Enclosing_Dynamic_Scope
+ (Lhs_Entity)))),
+ Reason => PE_Accessibility_Check_Failed);
+
+ Access_Level_Update : constant Node_Id :=
+ Make_Assignment_Statement (Loc,
+ Name =>
+ New_Occurrence_Of
+ (Effective_Extra_Accessibility
+ (Entity (Lhs)), Loc),
+ Expression =>
+ Dynamic_Accessibility_Level (Rhs));
+
+ begin
+ if not Accessibility_Checks_Suppressed (Entity (Lhs)) then
+ Insert_Action (N, Access_Check);
+ end if;
+
+ Insert_Action (N, Access_Level_Update);
+ end;
+ end if;
+
+ -- Case of assignment to a bit packed array element. If there is a
+ -- change of representation this must be expanded into components,
+ -- otherwise this is a bit-field assignment.
+
+ if Nkind (Lhs) = N_Indexed_Component
+ and then Is_Bit_Packed_Array (Etype (Prefix (Lhs)))
+ then
+ -- Normal case, no change of representation
+
+ if not Crep then
+ Expand_Bit_Packed_Element_Set (N);
+ return;
+
+ -- Change of representation case
+
+ else
+ -- Generate the following, to force component-by-component
+ -- assignments in an efficient way. Otherwise each component
+ -- will require a temporary and two bit-field manipulations.
+
+ -- T1 : Elmt_Type;
+ -- T1 := RhS;
+ -- Lhs := T1;
+
+ declare
+ Tnn : constant Entity_Id := Make_Temporary (Loc, 'T');
+ Stats : List_Id;
+
+ begin
+ Stats :=
+ New_List (
+ Make_Object_Declaration (Loc,
+ Defining_Identifier => Tnn,
+ Object_Definition =>
+ New_Occurrence_Of (Etype (Lhs), Loc)),
+ Make_Assignment_Statement (Loc,
+ Name => New_Occurrence_Of (Tnn, Loc),
+ Expression => Relocate_Node (Rhs)),
+ Make_Assignment_Statement (Loc,
+ Name => Relocate_Node (Lhs),
+ Expression => New_Occurrence_Of (Tnn, Loc)));
+
+ Insert_Actions (N, Stats);
+ Rewrite (N, Make_Null_Statement (Loc));
+ Analyze (N);
+ end;
+ end if;
+
+ -- Build-in-place function call case. Note that we're not yet doing
+ -- build-in-place for user-written assignment statements (the assignment
+ -- here came from an aggregate.)
+
+ elsif Ada_Version >= Ada_2005
+ and then Is_Build_In_Place_Function_Call (Rhs)
+ then
+ Make_Build_In_Place_Call_In_Assignment (N, Rhs);
+
+ elsif Is_Tagged_Type (Typ) and then Is_Value_Type (Etype (Lhs)) then
+
+ -- Nothing to do for valuetypes
+ -- ??? Set_Scope_Is_Transient (False);
+
+ return;
+
+ elsif Is_Tagged_Type (Typ)
+ or else (Needs_Finalization (Typ) and then not Is_Array_Type (Typ))
+ then
+ Tagged_Case : declare
+ L : List_Id := No_List;
+ Expand_Ctrl_Actions : constant Boolean := not No_Ctrl_Actions (N);
+
+ begin
+ -- In the controlled case, we ensure that function calls are
+ -- evaluated before finalizing the target. In all cases, it makes
+ -- the expansion easier if the side-effects are removed first.
+
+ Remove_Side_Effects (Lhs);
+ Remove_Side_Effects (Rhs);
+
+ -- Avoid recursion in the mechanism
+
+ Set_Analyzed (N);
+
+ -- If dispatching assignment, we need to dispatch to _assign
+
+ if Is_Class_Wide_Type (Typ)
+
+ -- If the type is tagged, we may as well use the predefined
+ -- primitive assignment. This avoids inlining a lot of code
+ -- and in the class-wide case, the assignment is replaced
+ -- by a dispatching call to _assign. It is suppressed in the
+ -- case of assignments created by the expander that correspond
+ -- to initializations, where we do want to copy the tag
+ -- (Expand_Ctrl_Actions flag is set True in this case). It is
+ -- also suppressed if restriction No_Dispatching_Calls is in
+ -- force because in that case predefined primitives are not
+ -- generated.
+
+ or else (Is_Tagged_Type (Typ)
+ and then not Is_Value_Type (Etype (Lhs))
+ and then Chars (Current_Scope) /= Name_uAssign
+ and then Expand_Ctrl_Actions
+ and then
+ not Restriction_Active (No_Dispatching_Calls))
+ then
+ if Is_Limited_Type (Typ) then
+
+ -- This can happen in an instance when the formal is an
+ -- extension of a limited interface, and the actual is
+ -- limited. This is an error according to AI05-0087, but
+ -- is not caught at the point of instantiation in earlier
+ -- versions.
+
+ -- This is wrong, error messages cannot be issued during
+ -- expansion, since they would be missed in -gnatc mode ???
+
+ Error_Msg_N ("assignment not available on limited type", N);
+ return;
+ end if;
+
+ -- Fetch the primitive op _assign and proper type to call it.
+ -- Because of possible conflicts between private and full view,
+ -- fetch the proper type directly from the operation profile.
+
+ declare
+ Op : constant Entity_Id :=
+ Find_Prim_Op (Typ, Name_uAssign);
+ F_Typ : Entity_Id := Etype (First_Formal (Op));
+
+ begin
+ -- If the assignment is dispatching, make sure to use the
+ -- proper type.
+
+ if Is_Class_Wide_Type (Typ) then
+ F_Typ := Class_Wide_Type (F_Typ);
+ end if;
+
+ L := New_List;
+
+ -- In case of assignment to a class-wide tagged type, before
+ -- the assignment we generate run-time check to ensure that
+ -- the tags of source and target match.
+
+ if not Tag_Checks_Suppressed (Typ)
+ and then Is_Class_Wide_Type (Typ)
+ and then Is_Tagged_Type (Typ)
+ and then Is_Tagged_Type (Underlying_Type (Etype (Rhs)))
+ then
+ Append_To (L,
+ Make_Raise_Constraint_Error (Loc,
+ Condition =>
+ Make_Op_Ne (Loc,
+ Left_Opnd =>
+ Make_Selected_Component (Loc,
+ Prefix => Duplicate_Subexpr (Lhs),
+ Selector_Name =>
+ Make_Identifier (Loc, Name_uTag)),
+ Right_Opnd =>
+ Make_Selected_Component (Loc,
+ Prefix => Duplicate_Subexpr (Rhs),
+ Selector_Name =>
+ Make_Identifier (Loc, Name_uTag))),
+ Reason => CE_Tag_Check_Failed));
+ end if;
+
+ declare
+ Left_N : Node_Id := Duplicate_Subexpr (Lhs);
+ Right_N : Node_Id := Duplicate_Subexpr (Rhs);
+
+ begin
+ -- In order to dispatch the call to _assign the type of
+ -- the actuals must match. Add conversion (if required).
+
+ if Etype (Lhs) /= F_Typ then
+ Left_N := Unchecked_Convert_To (F_Typ, Left_N);
+ end if;
+
+ if Etype (Rhs) /= F_Typ then
+ Right_N := Unchecked_Convert_To (F_Typ, Right_N);
+ end if;
+
+ Append_To (L,
+ Make_Procedure_Call_Statement (Loc,
+ Name => New_Reference_To (Op, Loc),
+ Parameter_Associations => New_List (
+ Node1 => Left_N,
+ Node2 => Right_N)));
+ end;
+ end;
+
+ else
+ L := Make_Tag_Ctrl_Assignment (N);
+
+ -- We can't afford to have destructive Finalization Actions in
+ -- the Self assignment case, so if the target and the source
+ -- are not obviously different, code is generated to avoid the
+ -- self assignment case:
+
+ -- if lhs'address /= rhs'address then
+ -- <code for controlled and/or tagged assignment>
+ -- end if;
+
+ -- Skip this if Restriction (No_Finalization) is active
+
+ if not Statically_Different (Lhs, Rhs)
+ and then Expand_Ctrl_Actions
+ and then not Restriction_Active (No_Finalization)
+ then
+ L := New_List (
+ Make_Implicit_If_Statement (N,
+ Condition =>
+ Make_Op_Ne (Loc,
+ Left_Opnd =>
+ Make_Attribute_Reference (Loc,
+ Prefix => Duplicate_Subexpr (Lhs),
+ Attribute_Name => Name_Address),
+
+ Right_Opnd =>
+ Make_Attribute_Reference (Loc,
+ Prefix => Duplicate_Subexpr (Rhs),
+ Attribute_Name => Name_Address)),
+
+ Then_Statements => L));
+ end if;
+
+ -- We need to set up an exception handler for implementing
+ -- 7.6.1(18). The remaining adjustments are tackled by the
+ -- implementation of adjust for record_controllers (see
+ -- s-finimp.adb).
+
+ -- This is skipped if we have no finalization
+
+ if Expand_Ctrl_Actions
+ and then not Restriction_Active (No_Finalization)
+ then
+ L := New_List (
+ Make_Block_Statement (Loc,
+ Handled_Statement_Sequence =>
+ Make_Handled_Sequence_Of_Statements (Loc,
+ Statements => L,
+ Exception_Handlers => New_List (
+ Make_Handler_For_Ctrl_Operation (Loc)))));
+ end if;
+ end if;
+
+ Rewrite (N,
+ Make_Block_Statement (Loc,
+ Handled_Statement_Sequence =>
+ Make_Handled_Sequence_Of_Statements (Loc, Statements => L)));
+
+ -- If no restrictions on aborts, protect the whole assignment
+ -- for controlled objects as per 9.8(11).
+
+ if Needs_Finalization (Typ)
+ and then Expand_Ctrl_Actions
+ and then Abort_Allowed
+ then
+ declare
+ Blk : constant Entity_Id :=
+ New_Internal_Entity
+ (E_Block, Current_Scope, Sloc (N), 'B');
+
+ begin
+ Set_Scope (Blk, Current_Scope);
+ Set_Etype (Blk, Standard_Void_Type);
+ Set_Identifier (N, New_Occurrence_Of (Blk, Sloc (N)));
+
+ Prepend_To (L, Build_Runtime_Call (Loc, RE_Abort_Defer));
+ Set_At_End_Proc (Handled_Statement_Sequence (N),
+ New_Occurrence_Of (RTE (RE_Abort_Undefer_Direct), Loc));
+ Expand_At_End_Handler
+ (Handled_Statement_Sequence (N), Blk);
+ end;
+ end if;
+
+ -- N has been rewritten to a block statement for which it is
+ -- known by construction that no checks are necessary: analyze
+ -- it with all checks suppressed.
+
+ Analyze (N, Suppress => All_Checks);
+ return;
+ end Tagged_Case;
+
+ -- Array types
+
+ elsif Is_Array_Type (Typ) then
+ declare
+ Actual_Rhs : Node_Id := Rhs;
+
+ begin
+ while Nkind_In (Actual_Rhs, N_Type_Conversion,
+ N_Qualified_Expression)
+ loop
+ Actual_Rhs := Expression (Actual_Rhs);
+ end loop;
+
+ Expand_Assign_Array (N, Actual_Rhs);
+ return;
+ end;
+
+ -- Record types
+
+ elsif Is_Record_Type (Typ) then
+ Expand_Assign_Record (N);
+ return;
+
+ -- Scalar types. This is where we perform the processing related to the
+ -- requirements of (RM 13.9.1(9-11)) concerning the handling of invalid
+ -- scalar values.
+
+ elsif Is_Scalar_Type (Typ) then
+
+ -- Case where right side is known valid
+
+ if Expr_Known_Valid (Rhs) then
+
+ -- Here the right side is valid, so it is fine. The case to deal
+ -- with is when the left side is a local variable reference whose
+ -- value is not currently known to be valid. If this is the case,
+ -- and the assignment appears in an unconditional context, then
+ -- we can mark the left side as now being valid if one of these
+ -- conditions holds:
+
+ -- The expression of the right side has Do_Range_Check set so
+ -- that we know a range check will be performed. Note that it
+ -- can be the case that a range check is omitted because we
+ -- make the assumption that we can assume validity for operands
+ -- appearing in the right side in determining whether a range
+ -- check is required
+
+ -- The subtype of the right side matches the subtype of the
+ -- left side. In this case, even though we have not checked
+ -- the range of the right side, we know it is in range of its
+ -- subtype if the expression is valid.
+
+ if Is_Local_Variable_Reference (Lhs)
+ and then not Is_Known_Valid (Entity (Lhs))
+ and then In_Unconditional_Context (N)
+ then
+ if Do_Range_Check (Rhs)
+ or else Etype (Lhs) = Etype (Rhs)
+ then
+ Set_Is_Known_Valid (Entity (Lhs), True);
+ end if;
+ end if;
+
+ -- Case where right side may be invalid in the sense of the RM
+ -- reference above. The RM does not require that we check for the
+ -- validity on an assignment, but it does require that the assignment
+ -- of an invalid value not cause erroneous behavior.
+
+ -- The general approach in GNAT is to use the Is_Known_Valid flag
+ -- to avoid the need for validity checking on assignments. However
+ -- in some cases, we have to do validity checking in order to make
+ -- sure that the setting of this flag is correct.
+
+ else
+ -- Validate right side if we are validating copies
+
+ if Validity_Checks_On
+ and then Validity_Check_Copies
+ then
+ -- Skip this if left hand side is an array or record component
+ -- and elementary component validity checks are suppressed.
+
+ if Nkind_In (Lhs, N_Selected_Component, N_Indexed_Component)
+ and then not Validity_Check_Components
+ then
+ null;
+ else
+ Ensure_Valid (Rhs);
+ end if;
+
+ -- We can propagate this to the left side where appropriate
+
+ if Is_Local_Variable_Reference (Lhs)
+ and then not Is_Known_Valid (Entity (Lhs))
+ and then In_Unconditional_Context (N)
+ then
+ Set_Is_Known_Valid (Entity (Lhs), True);
+ end if;
+
+ -- Otherwise check to see what should be done
+
+ -- If left side is a local variable, then we just set its flag to
+ -- indicate that its value may no longer be valid, since we are
+ -- copying a potentially invalid value.
+
+ elsif Is_Local_Variable_Reference (Lhs) then
+ Set_Is_Known_Valid (Entity (Lhs), False);
+
+ -- Check for case of a nonlocal variable on the left side which
+ -- is currently known to be valid. In this case, we simply ensure
+ -- that the right side is valid. We only play the game of copying
+ -- validity status for local variables, since we are doing this
+ -- statically, not by tracing the full flow graph.
+
+ elsif Is_Entity_Name (Lhs)
+ and then Is_Known_Valid (Entity (Lhs))
+ then
+ -- Note: If Validity_Checking mode is set to none, we ignore
+ -- the Ensure_Valid call so don't worry about that case here.
+
+ Ensure_Valid (Rhs);
+
+ -- In all other cases, we can safely copy an invalid value without
+ -- worrying about the status of the left side. Since it is not a
+ -- variable reference it will not be considered
+ -- as being known to be valid in any case.
+
+ else
+ null;
+ end if;
+ end if;
+ end if;
+
+ exception
+ when RE_Not_Available =>
+ return;
+ end Expand_N_Assignment_Statement;
+
+ ------------------------------
+ -- Expand_N_Block_Statement --
+ ------------------------------
+
+ -- Encode entity names defined in block statement
+
+ procedure Expand_N_Block_Statement (N : Node_Id) is
+ begin
+ Qualify_Entity_Names (N);
+ end Expand_N_Block_Statement;
+
+ -----------------------------
+ -- Expand_N_Case_Statement --
+ -----------------------------
+
+ procedure Expand_N_Case_Statement (N : Node_Id) is
+ Loc : constant Source_Ptr := Sloc (N);
+ Expr : constant Node_Id := Expression (N);
+ Alt : Node_Id;
+ Len : Nat;
+ Cond : Node_Id;
+ Choice : Node_Id;
+ Chlist : List_Id;
+
+ begin
+ -- Check for the situation where we know at compile time which branch
+ -- will be taken
+
+ if Compile_Time_Known_Value (Expr) then
+ Alt := Find_Static_Alternative (N);
+
+ Process_Statements_For_Controlled_Objects (Alt);
+
+ -- Move statements from this alternative after the case statement.
+ -- They are already analyzed, so will be skipped by the analyzer.
+
+ Insert_List_After (N, Statements (Alt));
+
+ -- That leaves the case statement as a shell. So now we can kill all
+ -- other alternatives in the case statement.
+
+ Kill_Dead_Code (Expression (N));
+
+ declare
+ Dead_Alt : Node_Id;
+
+ begin
+ -- Loop through case alternatives, skipping pragmas, and skipping
+ -- the one alternative that we select (and therefore retain).
+
+ Dead_Alt := First (Alternatives (N));
+ while Present (Dead_Alt) loop
+ if Dead_Alt /= Alt
+ and then Nkind (Dead_Alt) = N_Case_Statement_Alternative
+ then
+ Kill_Dead_Code (Statements (Dead_Alt), Warn_On_Deleted_Code);
+ end if;
+
+ Next (Dead_Alt);
+ end loop;
+ end;
+
+ Rewrite (N, Make_Null_Statement (Loc));
+ return;
+ end if;
+
+ -- Here if the choice is not determined at compile time
+
+ declare
+ Last_Alt : constant Node_Id := Last (Alternatives (N));
+
+ Others_Present : Boolean;
+ Others_Node : Node_Id;
+
+ Then_Stms : List_Id;
+ Else_Stms : List_Id;
+
+ begin
+ if Nkind (First (Discrete_Choices (Last_Alt))) = N_Others_Choice then
+ Others_Present := True;
+ Others_Node := Last_Alt;
+ else
+ Others_Present := False;
+ end if;
+
+ -- First step is to worry about possible invalid argument. The RM
+ -- requires (RM 5.4(13)) that if the result is invalid (e.g. it is
+ -- outside the base range), then Constraint_Error must be raised.
+
+ -- Case of validity check required (validity checks are on, the
+ -- expression is not known to be valid, and the case statement
+ -- comes from source -- no need to validity check internally
+ -- generated case statements).
+
+ if Validity_Check_Default then
+ Ensure_Valid (Expr);
+ end if;
+
+ -- If there is only a single alternative, just replace it with the
+ -- sequence of statements since obviously that is what is going to
+ -- be executed in all cases.
+
+ Len := List_Length (Alternatives (N));
+
+ if Len = 1 then
+
+ -- We still need to evaluate the expression if it has any side
+ -- effects.
+
+ Remove_Side_Effects (Expression (N));
+
+ Alt := First (Alternatives (N));
+
+ Process_Statements_For_Controlled_Objects (Alt);
+ Insert_List_After (N, Statements (Alt));
+
+ -- That leaves the case statement as a shell. The alternative that
+ -- will be executed is reset to a null list. So now we can kill
+ -- the entire case statement.
+
+ Kill_Dead_Code (Expression (N));
+ Rewrite (N, Make_Null_Statement (Loc));
+ return;
+
+ -- An optimization. If there are only two alternatives, and only
+ -- a single choice, then rewrite the whole case statement as an
+ -- if statement, since this can result in subsequent optimizations.
+ -- This helps not only with case statements in the source of a
+ -- simple form, but also with generated code (discriminant check
+ -- functions in particular)
+
+ elsif Len = 2 then
+ Chlist := Discrete_Choices (First (Alternatives (N)));
+
+ if List_Length (Chlist) = 1 then
+ Choice := First (Chlist);
+
+ Then_Stms := Statements (First (Alternatives (N)));
+ Else_Stms := Statements (Last (Alternatives (N)));
+
+ -- For TRUE, generate "expression", not expression = true
+
+ if Nkind (Choice) = N_Identifier
+ and then Entity (Choice) = Standard_True
+ then
+ Cond := Expression (N);
+
+ -- For FALSE, generate "expression" and switch then/else
+
+ elsif Nkind (Choice) = N_Identifier
+ and then Entity (Choice) = Standard_False
+ then
+ Cond := Expression (N);
+ Else_Stms := Statements (First (Alternatives (N)));
+ Then_Stms := Statements (Last (Alternatives (N)));
+
+ -- For a range, generate "expression in range"
+
+ elsif Nkind (Choice) = N_Range
+ or else (Nkind (Choice) = N_Attribute_Reference
+ and then Attribute_Name (Choice) = Name_Range)
+ or else (Is_Entity_Name (Choice)
+ and then Is_Type (Entity (Choice)))
+ or else Nkind (Choice) = N_Subtype_Indication
+ then
+ Cond :=
+ Make_In (Loc,
+ Left_Opnd => Expression (N),
+ Right_Opnd => Relocate_Node (Choice));
+
+ -- For any other subexpression "expression = value"
+
+ else
+ Cond :=
+ Make_Op_Eq (Loc,
+ Left_Opnd => Expression (N),
+ Right_Opnd => Relocate_Node (Choice));
+ end if;
+
+ -- Now rewrite the case as an IF
+
+ Rewrite (N,
+ Make_If_Statement (Loc,
+ Condition => Cond,
+ Then_Statements => Then_Stms,
+ Else_Statements => Else_Stms));
+ Analyze (N);
+ return;
+ end if;
+ end if;
+
+ -- If the last alternative is not an Others choice, replace it with
+ -- an N_Others_Choice. Note that we do not bother to call Analyze on
+ -- the modified case statement, since it's only effect would be to
+ -- compute the contents of the Others_Discrete_Choices which is not
+ -- needed by the back end anyway.
+
+ -- The reason we do this is that the back end always needs some
+ -- default for a switch, so if we have not supplied one in the
+ -- processing above for validity checking, then we need to supply
+ -- one here.
+
+ if not Others_Present then
+ Others_Node := Make_Others_Choice (Sloc (Last_Alt));
+ Set_Others_Discrete_Choices
+ (Others_Node, Discrete_Choices (Last_Alt));
+ Set_Discrete_Choices (Last_Alt, New_List (Others_Node));
+ end if;
+
+ Alt := First (Alternatives (N));
+ while Present (Alt)
+ and then Nkind (Alt) = N_Case_Statement_Alternative
+ loop
+ Process_Statements_For_Controlled_Objects (Alt);
+ Next (Alt);
+ end loop;
+ end;
+ end Expand_N_Case_Statement;
+
+ -----------------------------
+ -- Expand_N_Exit_Statement --
+ -----------------------------
+
+ -- The only processing required is to deal with a possible C/Fortran
+ -- boolean value used as the condition for the exit statement.
+
+ procedure Expand_N_Exit_Statement (N : Node_Id) is
+ begin
+ Adjust_Condition (Condition (N));
+ end Expand_N_Exit_Statement;
+
+ -----------------------------
+ -- Expand_N_Goto_Statement --
+ -----------------------------
+
+ -- Add poll before goto if polling active
+
+ procedure Expand_N_Goto_Statement (N : Node_Id) is
+ begin
+ Generate_Poll_Call (N);
+ end Expand_N_Goto_Statement;
+
+ ---------------------------
+ -- Expand_N_If_Statement --
+ ---------------------------
+
+ -- First we deal with the case of C and Fortran convention boolean values,
+ -- with zero/non-zero semantics.
+
+ -- Second, we deal with the obvious rewriting for the cases where the
+ -- condition of the IF is known at compile time to be True or False.
+
+ -- Third, we remove elsif parts which have non-empty Condition_Actions and
+ -- rewrite as independent if statements. For example:
+
+ -- if x then xs
+ -- elsif y then ys
+ -- ...
+ -- end if;
+
+ -- becomes
+ --
+ -- if x then xs
+ -- else
+ -- <<condition actions of y>>
+ -- if y then ys
+ -- ...
+ -- end if;
+ -- end if;
+
+ -- This rewriting is needed if at least one elsif part has a non-empty
+ -- Condition_Actions list. We also do the same processing if there is a
+ -- constant condition in an elsif part (in conjunction with the first
+ -- processing step mentioned above, for the recursive call made to deal
+ -- with the created inner if, this deals with properly optimizing the
+ -- cases of constant elsif conditions).
+
+ procedure Expand_N_If_Statement (N : Node_Id) is
+ Loc : constant Source_Ptr := Sloc (N);
+ Hed : Node_Id;
+ E : Node_Id;
+ New_If : Node_Id;
+
+ Warn_If_Deleted : constant Boolean :=
+ Warn_On_Deleted_Code and then Comes_From_Source (N);
+ -- Indicates whether we want warnings when we delete branches of the
+ -- if statement based on constant condition analysis. We never want
+ -- these warnings for expander generated code.
+
+ begin
+ Process_Statements_For_Controlled_Objects (N);
+
+ Adjust_Condition (Condition (N));
+
+ -- The following loop deals with constant conditions for the IF. We
+ -- need a loop because as we eliminate False conditions, we grab the
+ -- first elsif condition and use it as the primary condition.
+
+ while Compile_Time_Known_Value (Condition (N)) loop
+
+ -- If condition is True, we can simply rewrite the if statement now
+ -- by replacing it by the series of then statements.
+
+ if Is_True (Expr_Value (Condition (N))) then
+
+ -- All the else parts can be killed
+
+ Kill_Dead_Code (Elsif_Parts (N), Warn_If_Deleted);
+ Kill_Dead_Code (Else_Statements (N), Warn_If_Deleted);
+
+ Hed := Remove_Head (Then_Statements (N));
+ Insert_List_After (N, Then_Statements (N));
+ Rewrite (N, Hed);
+ return;
+
+ -- If condition is False, then we can delete the condition and
+ -- the Then statements
+
+ else
+ -- We do not delete the condition if constant condition warnings
+ -- are enabled, since otherwise we end up deleting the desired
+ -- warning. Of course the backend will get rid of this True/False
+ -- test anyway, so nothing is lost here.
+
+ if not Constant_Condition_Warnings then
+ Kill_Dead_Code (Condition (N));
+ end if;
+
+ Kill_Dead_Code (Then_Statements (N), Warn_If_Deleted);
+
+ -- If there are no elsif statements, then we simply replace the
+ -- entire if statement by the sequence of else statements.
+
+ if No (Elsif_Parts (N)) then
+ if No (Else_Statements (N))
+ or else Is_Empty_List (Else_Statements (N))
+ then
+ Rewrite (N,
+ Make_Null_Statement (Sloc (N)));
+ else
+ Hed := Remove_Head (Else_Statements (N));
+ Insert_List_After (N, Else_Statements (N));
+ Rewrite (N, Hed);
+ end if;
+
+ return;
+
+ -- If there are elsif statements, the first of them becomes the
+ -- if/then section of the rebuilt if statement This is the case
+ -- where we loop to reprocess this copied condition.
+
+ else
+ Hed := Remove_Head (Elsif_Parts (N));
+ Insert_Actions (N, Condition_Actions (Hed));
+ Set_Condition (N, Condition (Hed));
+ Set_Then_Statements (N, Then_Statements (Hed));
+
+ -- Hed might have been captured as the condition determining
+ -- the current value for an entity. Now it is detached from
+ -- the tree, so a Current_Value pointer in the condition might
+ -- need to be updated.
+
+ Set_Current_Value_Condition (N);
+
+ if Is_Empty_List (Elsif_Parts (N)) then
+ Set_Elsif_Parts (N, No_List);
+ end if;
+ end if;
+ end if;
+ end loop;
+
+ -- Loop through elsif parts, dealing with constant conditions and
+ -- possible condition actions that are present.
+
+ if Present (Elsif_Parts (N)) then
+ E := First (Elsif_Parts (N));
+ while Present (E) loop
+ Process_Statements_For_Controlled_Objects (E);
+
+ Adjust_Condition (Condition (E));
+
+ -- If there are condition actions, then rewrite the if statement
+ -- as indicated above. We also do the same rewrite for a True or
+ -- False condition. The further processing of this constant
+ -- condition is then done by the recursive call to expand the
+ -- newly created if statement
+
+ if Present (Condition_Actions (E))
+ or else Compile_Time_Known_Value (Condition (E))
+ then
+ -- Note this is not an implicit if statement, since it is part
+ -- of an explicit if statement in the source (or of an implicit
+ -- if statement that has already been tested).
+
+ New_If :=
+ Make_If_Statement (Sloc (E),
+ Condition => Condition (E),
+ Then_Statements => Then_Statements (E),
+ Elsif_Parts => No_List,
+ Else_Statements => Else_Statements (N));
+
+ -- Elsif parts for new if come from remaining elsif's of parent
+
+ while Present (Next (E)) loop
+ if No (Elsif_Parts (New_If)) then
+ Set_Elsif_Parts (New_If, New_List);
+ end if;
+
+ Append (Remove_Next (E), Elsif_Parts (New_If));
+ end loop;
+
+ Set_Else_Statements (N, New_List (New_If));
+
+ if Present (Condition_Actions (E)) then
+ Insert_List_Before (New_If, Condition_Actions (E));
+ end if;
+
+ Remove (E);
+
+ if Is_Empty_List (Elsif_Parts (N)) then
+ Set_Elsif_Parts (N, No_List);
+ end if;
+
+ Analyze (New_If);
+ return;
+
+ -- No special processing for that elsif part, move to next
+
+ else
+ Next (E);
+ end if;
+ end loop;
+ end if;
+
+ -- Some more optimizations applicable if we still have an IF statement
+
+ if Nkind (N) /= N_If_Statement then
+ return;
+ end if;
+
+ -- Another optimization, special cases that can be simplified
+
+ -- if expression then
+ -- return true;
+ -- else
+ -- return false;
+ -- end if;
+
+ -- can be changed to:
+
+ -- return expression;
+
+ -- and
+
+ -- if expression then
+ -- return false;
+ -- else
+ -- return true;
+ -- end if;
+
+ -- can be changed to:
+
+ -- return not (expression);
+
+ -- Only do these optimizations if we are at least at -O1 level and
+ -- do not do them if control flow optimizations are suppressed.
+
+ if Optimization_Level > 0
+ and then not Opt.Suppress_Control_Flow_Optimizations
+ then
+ if Nkind (N) = N_If_Statement
+ and then No (Elsif_Parts (N))
+ and then Present (Else_Statements (N))
+ and then List_Length (Then_Statements (N)) = 1
+ and then List_Length (Else_Statements (N)) = 1
+ then
+ declare
+ Then_Stm : constant Node_Id := First (Then_Statements (N));
+ Else_Stm : constant Node_Id := First (Else_Statements (N));
+
+ begin
+ if Nkind (Then_Stm) = N_Simple_Return_Statement
+ and then
+ Nkind (Else_Stm) = N_Simple_Return_Statement
+ then
+ declare
+ Then_Expr : constant Node_Id := Expression (Then_Stm);
+ Else_Expr : constant Node_Id := Expression (Else_Stm);
+
+ begin
+ if Nkind (Then_Expr) = N_Identifier
+ and then
+ Nkind (Else_Expr) = N_Identifier
+ then
+ if Entity (Then_Expr) = Standard_True
+ and then Entity (Else_Expr) = Standard_False
+ then
+ Rewrite (N,
+ Make_Simple_Return_Statement (Loc,
+ Expression => Relocate_Node (Condition (N))));
+ Analyze (N);
+ return;
+
+ elsif Entity (Then_Expr) = Standard_False
+ and then Entity (Else_Expr) = Standard_True
+ then
+ Rewrite (N,
+ Make_Simple_Return_Statement (Loc,
+ Expression =>
+ Make_Op_Not (Loc,
+ Right_Opnd =>
+ Relocate_Node (Condition (N)))));
+ Analyze (N);
+ return;
+ end if;
+ end if;
+ end;
+ end if;
+ end;
+ end if;
+ end if;
+ end Expand_N_If_Statement;
+
+ --------------------------
+ -- Expand_Iterator_Loop --
+ --------------------------
+
+ procedure Expand_Iterator_Loop (N : Node_Id) is
+ Isc : constant Node_Id := Iteration_Scheme (N);
+ I_Spec : constant Node_Id := Iterator_Specification (Isc);
+ Id : constant Entity_Id := Defining_Identifier (I_Spec);
+ Loc : constant Source_Ptr := Sloc (N);
+
+ Container : constant Node_Id := Name (I_Spec);
+ Container_Typ : constant Entity_Id := Base_Type (Etype (Container));
+ Cursor : Entity_Id;
+ Iterator : Entity_Id;
+ New_Loop : Node_Id;
+ Stats : List_Id := Statements (N);
+
+ begin
+ -- Processing for arrays
+
+ if Is_Array_Type (Container_Typ) then
+ Expand_Iterator_Loop_Over_Array (N);
+ return;
+ end if;
+
+ -- Processing for containers
+
+ -- For an "of" iterator the name is a container expression, which
+ -- is transformed into a call to the default iterator.
+
+ -- For an iterator of the form "in" the name is a function call
+ -- that delivers an iterator type.
+
+ -- In both cases, analysis of the iterator has introduced an object
+ -- declaration to capture the domain, so that Container is an entity.
+
+ -- The for loop is expanded into a while loop which uses a container
+ -- specific cursor to desgnate each element.
+
+ -- Iter : Iterator_Type := Container.Iterate;
+ -- Cursor : Cursor_type := First (Iter);
+ -- while Has_Element (Iter) loop
+ -- declare
+ -- -- The block is added when Element_Type is controlled
+
+ -- Obj : Pack.Element_Type := Element (Cursor);
+ -- -- for the "of" loop form
+ -- begin
+ -- <original loop statements>
+ -- end;
+
+ -- Cursor := Iter.Next (Cursor);
+ -- end loop;
+
+ -- If "reverse" is present, then the initialization of the cursor
+ -- uses Last and the step becomes Prev. Pack is the name of the
+ -- scope where the container package is instantiated.
+
+ declare
+ Element_Type : constant Entity_Id := Etype (Id);
+ Iter_Type : Entity_Id;
+ Pack : Entity_Id;
+ Decl : Node_Id;
+ Name_Init : Name_Id;
+ Name_Step : Name_Id;
+
+ begin
+ -- The type of the iterator is the return type of the Iterate
+ -- function used. For the "of" form this is the default iterator
+ -- for the type, otherwise it is the type of the explicit
+ -- function used in the iterator specification. The most common
+ -- case will be an Iterate function in the container package.
+
+ -- The primitive operations of the container type may not be
+ -- use-visible, so we introduce the name of the enclosing package
+ -- in the declarations below. The Iterator type is declared in a
+ -- an instance within the container package itself.
+
+ -- If the container type is a derived type, the cursor type is
+ -- found in the package of the parent type.
+
+ if Is_Derived_Type (Container_Typ) then
+ Pack := Scope (Root_Type (Container_Typ));
+ else
+ Pack := Scope (Container_Typ);
+ end if;
+
+ Iter_Type := Etype (Name (I_Spec));
+
+ -- The "of" case uses an internally generated cursor whose type
+ -- is found in the container package. The domain of iteration
+ -- is expanded into a call to the default Iterator function, but
+ -- this expansion does not take place in quantified expressions
+ -- that are analyzed with expansion disabled, and in that case the
+ -- type of the iterator must be obtained from the aspect.
+
+ if Of_Present (I_Spec) then
+ declare
+ Default_Iter : constant Entity_Id :=
+ Entity
+ (Find_Aspect
+ (Etype (Container),
+ Aspect_Default_Iterator));
+
+ Container_Arg : Node_Id;
+ Ent : Entity_Id;
+
+ begin
+ Cursor := Make_Temporary (Loc, 'I');
+
+ -- For an container element iterator, the iterator type
+ -- is obtained from the corresponding aspect, whose return
+ -- type is descended from the corresponding interface type
+ -- in some instance of Ada.Iterator_Interfaces. The actuals
+ -- of that instantiation are Cursor and Has_Element.
+
+ Iter_Type := Etype (Default_Iter);
+
+ -- The iterator type, which is a class_wide type, may itself
+ -- be derived locally, so the desired instantiation is the
+ -- scope of the root type of the iterator type.
+
+ Pack := Scope (Root_Type (Etype (Iter_Type)));
+
+ -- Rewrite domain of iteration as a call to the default
+ -- iterator for the container type. If the container is
+ -- a derived type and the aspect is inherited, convert
+ -- container to parent type. The Cursor type is also
+ -- inherited from the scope of the parent.
+
+ if Base_Type (Etype (Container)) =
+ Base_Type (Etype (First_Formal (Default_Iter)))
+ then
+ Container_Arg := New_Copy_Tree (Container);
+
+ else
+ Container_Arg :=
+ Make_Type_Conversion (Loc,
+ Subtype_Mark =>
+ New_Occurrence_Of
+ (Etype (First_Formal (Default_Iter)), Loc),
+ Expression => New_Copy_Tree (Container));
+ end if;
+
+ Rewrite (Name (I_Spec),
+ Make_Function_Call (Loc,
+ Name => New_Occurrence_Of (Default_Iter, Loc),
+ Parameter_Associations =>
+ New_List (Container_Arg)));
+ Analyze_And_Resolve (Name (I_Spec));
+
+ -- Find cursor type in proper iterator package, which is an
+ -- instantiation of Iterator_Interfaces.
+
+ Ent := First_Entity (Pack);
+ while Present (Ent) loop
+ if Chars (Ent) = Name_Cursor then
+ Set_Etype (Cursor, Etype (Ent));
+ exit;
+ end if;
+ Next_Entity (Ent);
+ end loop;
+
+ -- Generate:
+ -- Id : Element_Type renames Container (Cursor);
+ -- This assumes that the container type has an indexing
+ -- operation with Cursor. The check that this operation
+ -- exists is performed in Check_Container_Indexing.
+
+ Decl :=
+ Make_Object_Renaming_Declaration (Loc,
+ Defining_Identifier => Id,
+ Subtype_Mark =>
+ New_Reference_To (Element_Type, Loc),
+ Name =>
+ Make_Indexed_Component (Loc,
+ Prefix => Relocate_Node (Container_Arg),
+ Expressions =>
+ New_List (New_Occurrence_Of (Cursor, Loc))));
+
+ -- The defining identifier in the iterator is user-visible
+ -- and must be visible in the debugger.
+
+ Set_Debug_Info_Needed (Id);
+
+ -- If the container holds controlled objects, wrap the loop
+ -- statements and element renaming declaration with a block.
+ -- This ensures that the result of Element (Cusor) is
+ -- cleaned up after each iteration of the loop.
+
+ if Needs_Finalization (Element_Type) then
+
+ -- Generate:
+ -- declare
+ -- Id : Element_Type := Element (curosr);
+ -- begin
+ -- <original loop statements>
+ -- end;
+
+ Stats := New_List (
+ Make_Block_Statement (Loc,
+ Declarations => New_List (Decl),
+ Handled_Statement_Sequence =>
+ Make_Handled_Sequence_Of_Statements (Loc,
+ Statements => Stats)));
+
+ -- Elements do not need finalization
+
+ else
+ Prepend_To (Stats, Decl);
+ end if;
+ end;
+
+ -- X in Iterate (S) : type of iterator is type of explicitly
+ -- given Iterate function, and the loop variable is the cursor.
+ -- It will be assigned in the loop and must be a variable.
+
+ else
+ Cursor := Id;
+ Set_Ekind (Cursor, E_Variable);
+ end if;
+
+ Iterator := Make_Temporary (Loc, 'I');
+
+ -- Determine the advancement and initialization steps for the
+ -- cursor.
+
+ -- Analysis of the expanded loop will verify that the container
+ -- has a reverse iterator.
+
+ if Reverse_Present (I_Spec) then
+ Name_Init := Name_Last;
+ Name_Step := Name_Previous;
+
+ else
+ Name_Init := Name_First;
+ Name_Step := Name_Next;
+ end if;
+
+ -- For both iterator forms, add a call to the step operation to
+ -- advance the cursor. Generate:
+
+ -- Cursor := Iterator.Next (Cursor);
+
+ -- or else
+
+ -- Cursor := Next (Cursor);
+
+ declare
+ Rhs : Node_Id;
+
+ begin
+ Rhs :=
+ Make_Function_Call (Loc,
+ Name =>
+ Make_Selected_Component (Loc,
+ Prefix => New_Reference_To (Iterator, Loc),
+ Selector_Name => Make_Identifier (Loc, Name_Step)),
+ Parameter_Associations => New_List (
+ New_Reference_To (Cursor, Loc)));
+
+ Append_To (Stats,
+ Make_Assignment_Statement (Loc,
+ Name => New_Occurrence_Of (Cursor, Loc),
+ Expression => Rhs));
+ end;
+
+ -- Generate:
+ -- while Iterator.Has_Element loop
+ -- <Stats>
+ -- end loop;
+
+ -- Has_Element is the second actual in the iterator package
+
+ New_Loop :=
+ Make_Loop_Statement (Loc,
+ Iteration_Scheme =>
+ Make_Iteration_Scheme (Loc,
+ Condition =>
+ Make_Function_Call (Loc,
+ Name =>
+ New_Occurrence_Of (
+ Next_Entity (First_Entity (Pack)), Loc),
+ Parameter_Associations =>
+ New_List (New_Reference_To (Cursor, Loc)))),
+
+ Statements => Stats,
+ End_Label => Empty);
+
+ -- If present, preserve identifier of loop, which can be used in
+ -- an exit statement in the body.
+
+ if Present (Identifier (N)) then
+ Set_Identifier (New_Loop, Relocate_Node (Identifier (N)));
+ end if;
+
+ -- Create the declarations for Iterator and cursor and insert them
+ -- before the source loop. Given that the domain of iteration is
+ -- already an entity, the iterator is just a renaming of that
+ -- entity. Possible optimization ???
+ -- Generate:
+
+ -- I : Iterator_Type renames Container;
+ -- C : Cursor_Type := Container.[First | Last];
+
+ Insert_Action (N,
+ Make_Object_Renaming_Declaration (Loc,
+ Defining_Identifier => Iterator,
+ Subtype_Mark => New_Occurrence_Of (Iter_Type, Loc),
+ Name => Relocate_Node (Name (I_Spec))));
+
+ -- Create declaration for cursor
+
+ declare
+ Decl : Node_Id;
+
+ begin
+ Decl :=
+ Make_Object_Declaration (Loc,
+ Defining_Identifier => Cursor,
+ Object_Definition =>
+ New_Occurrence_Of (Etype (Cursor), Loc),
+ Expression =>
+ Make_Selected_Component (Loc,
+ Prefix => New_Reference_To (Iterator, Loc),
+ Selector_Name =>
+ Make_Identifier (Loc, Name_Init)));
+
+ -- The cursor is only modified in expanded code, so it appears
+ -- as unassigned to the warning machinery. We must suppress
+ -- this spurious warning explicitly.
+
+ Set_Warnings_Off (Cursor);
+ Set_Assignment_OK (Decl);
+
+ Insert_Action (N, Decl);
+ end;
+
+ -- If the range of iteration is given by a function call that
+ -- returns a container, the finalization actions have been saved
+ -- in the Condition_Actions of the iterator. Insert them now at
+ -- the head of the loop.
+
+ if Present (Condition_Actions (Isc)) then
+ Insert_List_Before (N, Condition_Actions (Isc));
+ end if;
+ end;
+
+ Rewrite (N, New_Loop);
+ Analyze (N);
+ end Expand_Iterator_Loop;
+
+ -------------------------------------
+ -- Expand_Iterator_Loop_Over_Array --
+ -------------------------------------
+
+ procedure Expand_Iterator_Loop_Over_Array (N : Node_Id) is
+ Isc : constant Node_Id := Iteration_Scheme (N);
+ I_Spec : constant Node_Id := Iterator_Specification (Isc);
+ Array_Node : constant Node_Id := Name (I_Spec);
+ Array_Typ : constant Entity_Id := Base_Type (Etype (Array_Node));
+ Array_Dim : constant Pos := Number_Dimensions (Array_Typ);
+ Id : constant Entity_Id := Defining_Identifier (I_Spec);
+ Loc : constant Source_Ptr := Sloc (N);
+ Stats : constant List_Id := Statements (N);
+ Core_Loop : Node_Id;
+ Ind_Comp : Node_Id;
+ Iterator : Entity_Id;
+
+ -- Start of processing for Expand_Iterator_Loop_Over_Array
+
+ begin
+ -- for Element of Array loop
+
+ -- This case requires an internally generated cursor to iterate over
+ -- the array.
+
+ if Of_Present (I_Spec) then
+ Iterator := Make_Temporary (Loc, 'C');
+
+ -- Generate:
+ -- Element : Component_Type renames Array (Iterator);
+
+ Ind_Comp :=
+ Make_Indexed_Component (Loc,
+ Prefix => Relocate_Node (Array_Node),
+ Expressions => New_List (New_Reference_To (Iterator, Loc)));
+
+ Prepend_To (Stats,
+ Make_Object_Renaming_Declaration (Loc,
+ Defining_Identifier => Id,
+ Subtype_Mark =>
+ New_Reference_To (Component_Type (Array_Typ), Loc),
+ Name => Ind_Comp));
+
+ -- Mark the loop variable as needing debug info, so that expansion
+ -- of the renaming will result in Materialize_Entity getting set via
+ -- Debug_Renaming_Declaration. (This setting is needed here because
+ -- the setting in Freeze_Entity comes after the expansion, which is
+ -- too late. ???)
+
+ Set_Debug_Info_Needed (Id);
+
+ -- for Index in Array loop
+
+ -- This case utilizes the already given iterator name
+
+ else
+ Iterator := Id;
+ end if;
+
+ -- Generate:
+
+ -- for Iterator in [reverse] Array'Range (Array_Dim) loop
+ -- Element : Component_Type renames Array (Iterator);
+ -- <original loop statements>
+ -- end loop;
+
+ Core_Loop :=
+ Make_Loop_Statement (Loc,
+ Iteration_Scheme =>
+ Make_Iteration_Scheme (Loc,
+ Loop_Parameter_Specification =>
+ Make_Loop_Parameter_Specification (Loc,
+ Defining_Identifier => Iterator,
+ Discrete_Subtype_Definition =>
+ Make_Attribute_Reference (Loc,
+ Prefix => Relocate_Node (Array_Node),
+ Attribute_Name => Name_Range,
+ Expressions => New_List (
+ Make_Integer_Literal (Loc, Array_Dim))),
+ Reverse_Present => Reverse_Present (I_Spec))),
+ Statements => Stats,
+ End_Label => Empty);
+
+ -- Processing for multidimensional array
+
+ if Array_Dim > 1 then
+ for Dim in 1 .. Array_Dim - 1 loop
+ Iterator := Make_Temporary (Loc, 'C');
+
+ -- Generate the dimension loops starting from the innermost one
+
+ -- for Iterator in [reverse] Array'Range (Array_Dim - Dim) loop
+ -- <core loop>
+ -- end loop;
+
+ Core_Loop :=
+ Make_Loop_Statement (Loc,
+ Iteration_Scheme =>
+ Make_Iteration_Scheme (Loc,
+ Loop_Parameter_Specification =>
+ Make_Loop_Parameter_Specification (Loc,
+ Defining_Identifier => Iterator,
+ Discrete_Subtype_Definition =>
+ Make_Attribute_Reference (Loc,
+ Prefix => Relocate_Node (Array_Node),
+ Attribute_Name => Name_Range,
+ Expressions => New_List (
+ Make_Integer_Literal (Loc, Array_Dim - Dim))),
+ Reverse_Present => Reverse_Present (I_Spec))),
+ Statements => New_List (Core_Loop),
+ End_Label => Empty);
+
+ -- Update the previously created object renaming declaration with
+ -- the new iterator.
+
+ Prepend_To (Expressions (Ind_Comp),
+ New_Reference_To (Iterator, Loc));
+ end loop;
+ end if;
+
+ -- If original loop has a source name, preserve it so it can be
+ -- recognized by an exit statement in the body of the rewritten loop.
+ -- This only concerns source names: the generated name of an anonymous
+ -- loop will be create again during the subsequent analysis below.
+
+ if Present (Identifier (N))
+ and then Comes_From_Source (Identifier (N))
+ then
+ Set_Identifier (Core_Loop, Relocate_Node (Identifier (N)));
+ end if;
+
+ Rewrite (N, Core_Loop);
+ Analyze (N);
+ end Expand_Iterator_Loop_Over_Array;
+
+ -----------------------------
+ -- Expand_N_Loop_Statement --
+ -----------------------------
+
+ -- 1. Remove null loop entirely
+ -- 2. Deal with while condition for C/Fortran boolean
+ -- 3. Deal with loops with a non-standard enumeration type range
+ -- 4. Deal with while loops where Condition_Actions is set
+ -- 5. Deal with loops over predicated subtypes
+ -- 6. Deal with loops with iterators over arrays and containers
+ -- 7. Insert polling call if required
+
+ procedure Expand_N_Loop_Statement (N : Node_Id) is
+ Loc : constant Source_Ptr := Sloc (N);
+ Isc : constant Node_Id := Iteration_Scheme (N);
+
+ begin
+ -- Delete null loop
+
+ if Is_Null_Loop (N) then
+ Rewrite (N, Make_Null_Statement (Loc));
+ return;
+ end if;
+
+ Process_Statements_For_Controlled_Objects (N);
+
+ -- Deal with condition for C/Fortran Boolean
+
+ if Present (Isc) then
+ Adjust_Condition (Condition (Isc));
+ end if;
+
+ -- Generate polling call
+
+ if Is_Non_Empty_List (Statements (N)) then
+ Generate_Poll_Call (First (Statements (N)));
+ end if;
+
+ -- Nothing more to do for plain loop with no iteration scheme
+
+ if No (Isc) then
+ null;
+
+ -- Case of for loop (Loop_Parameter_Specification present)
+
+ -- Note: we do not have to worry about validity checking of the for loop
+ -- range bounds here, since they were frozen with constant declarations
+ -- and it is during that process that the validity checking is done.
+
+ elsif Present (Loop_Parameter_Specification (Isc)) then
+ declare
+ LPS : constant Node_Id := Loop_Parameter_Specification (Isc);
+ Loop_Id : constant Entity_Id := Defining_Identifier (LPS);
+ Ltype : constant Entity_Id := Etype (Loop_Id);
+ Btype : constant Entity_Id := Base_Type (Ltype);
+ Expr : Node_Id;
+ Decls : List_Id;
+ New_Id : Entity_Id;
+
+ begin
+ -- Deal with loop over predicates
+
+ if Is_Discrete_Type (Ltype)
+ and then Present (Predicate_Function (Ltype))
+ then
+ Expand_Predicated_Loop (N);
+
+ -- Handle the case where we have a for loop with the range type
+ -- being an enumeration type with non-standard representation.
+ -- In this case we expand:
+
+ -- for x in [reverse] a .. b loop
+ -- ...
+ -- end loop;
+
+ -- to
+
+ -- for xP in [reverse] integer
+ -- range etype'Pos (a) .. etype'Pos (b)
+ -- loop
+ -- declare
+ -- x : constant etype := Pos_To_Rep (xP);
+ -- begin
+ -- ...
+ -- end;
+ -- end loop;
+
+ elsif Is_Enumeration_Type (Btype)
+ and then Present (Enum_Pos_To_Rep (Btype))
+ then
+ New_Id :=
+ Make_Defining_Identifier (Loc,
+ Chars => New_External_Name (Chars (Loop_Id), 'P'));
+
+ -- If the type has a contiguous representation, successive
+ -- values can be generated as offsets from the first literal.
+
+ if Has_Contiguous_Rep (Btype) then
+ Expr :=
+ Unchecked_Convert_To (Btype,
+ Make_Op_Add (Loc,
+ Left_Opnd =>
+ Make_Integer_Literal (Loc,
+ Enumeration_Rep (First_Literal (Btype))),
+ Right_Opnd => New_Reference_To (New_Id, Loc)));
+ else
+ -- Use the constructed array Enum_Pos_To_Rep
+
+ Expr :=
+ Make_Indexed_Component (Loc,
+ Prefix =>
+ New_Reference_To (Enum_Pos_To_Rep (Btype), Loc),
+ Expressions =>
+ New_List (New_Reference_To (New_Id, Loc)));
+ end if;
+
+ -- Build declaration for loop identifier
+
+ Decls :=
+ New_List (
+ Make_Object_Declaration (Loc,
+ Defining_Identifier => Loop_Id,
+ Constant_Present => True,
+ Object_Definition => New_Reference_To (Ltype, Loc),
+ Expression => Expr));
+
+ Rewrite (N,
+ Make_Loop_Statement (Loc,
+ Identifier => Identifier (N),
+
+ Iteration_Scheme =>
+ Make_Iteration_Scheme (Loc,
+ Loop_Parameter_Specification =>
+ Make_Loop_Parameter_Specification (Loc,
+ Defining_Identifier => New_Id,
+ Reverse_Present => Reverse_Present (LPS),
+
+ Discrete_Subtype_Definition =>
+ Make_Subtype_Indication (Loc,
+
+ Subtype_Mark =>
+ New_Reference_To (Standard_Natural, Loc),
+
+ Constraint =>
+ Make_Range_Constraint (Loc,
+ Range_Expression =>
+ Make_Range (Loc,
+
+ Low_Bound =>
+ Make_Attribute_Reference (Loc,
+ Prefix =>
+ New_Reference_To (Btype, Loc),
+
+ Attribute_Name => Name_Pos,
+
+ Expressions => New_List (
+ Relocate_Node
+ (Type_Low_Bound (Ltype)))),
+
+ High_Bound =>
+ Make_Attribute_Reference (Loc,
+ Prefix =>
+ New_Reference_To (Btype, Loc),
+
+ Attribute_Name => Name_Pos,
+
+ Expressions => New_List (
+ Relocate_Node
+ (Type_High_Bound
+ (Ltype))))))))),
+
+ Statements => New_List (
+ Make_Block_Statement (Loc,
+ Declarations => Decls,
+ Handled_Statement_Sequence =>
+ Make_Handled_Sequence_Of_Statements (Loc,
+ Statements => Statements (N)))),
+
+ End_Label => End_Label (N)));
+
+ -- The loop parameter's entity must be removed from the loop
+ -- scope's entity list and rendered invisible, since it will
+ -- now be located in the new block scope. Any other entities
+ -- already associated with the loop scope, such as the loop
+ -- parameter's subtype, will remain there.
+
+ -- In an element loop, the loop will contain a declaration for
+ -- a cursor variable; otherwise the loop id is the first entity
+ -- in the scope constructed for the loop.
+
+ if Comes_From_Source (Loop_Id) then
+ pragma Assert (First_Entity (Scope (Loop_Id)) = Loop_Id);
+ null;
+ end if;
+
+ Set_First_Entity (Scope (Loop_Id), Next_Entity (Loop_Id));
+ Remove_Homonym (Loop_Id);
+
+ if Last_Entity (Scope (Loop_Id)) = Loop_Id then
+ Set_Last_Entity (Scope (Loop_Id), Empty);
+ end if;
+
+ Analyze (N);
+
+ -- Nothing to do with other cases of for loops
+
+ else
+ null;
+ end if;
+ end;
+
+ -- Second case, if we have a while loop with Condition_Actions set, then
+ -- we change it into a plain loop:
+
+ -- while C loop
+ -- ...
+ -- end loop;
+
+ -- changed to:
+
+ -- loop
+ -- <<condition actions>>
+ -- exit when not C;
+ -- ...
+ -- end loop
+
+ elsif Present (Isc)
+ and then Present (Condition_Actions (Isc))
+ and then Present (Condition (Isc))
+ then
+ declare
+ ES : Node_Id;
+
+ begin
+ ES :=
+ Make_Exit_Statement (Sloc (Condition (Isc)),
+ Condition =>
+ Make_Op_Not (Sloc (Condition (Isc)),
+ Right_Opnd => Condition (Isc)));
+
+ Prepend (ES, Statements (N));
+ Insert_List_Before (ES, Condition_Actions (Isc));
+
+ -- This is not an implicit loop, since it is generated in response
+ -- to the loop statement being processed. If this is itself
+ -- implicit, the restriction has already been checked. If not,
+ -- it is an explicit loop.
+
+ Rewrite (N,
+ Make_Loop_Statement (Sloc (N),
+ Identifier => Identifier (N),
+ Statements => Statements (N),
+ End_Label => End_Label (N)));
+
+ Analyze (N);
+ end;
+
+ -- Here to deal with iterator case
+
+ elsif Present (Isc)
+ and then Present (Iterator_Specification (Isc))
+ then
+ Expand_Iterator_Loop (N);
+ end if;
+
+ -- If the loop is subject to at least one Loop_Entry attribute, it
+ -- requires additional processing.
+
+ if Nkind (N) = N_Loop_Statement then
+ Expand_Loop_Entry_Attributes (N);
+ end if;
+ end Expand_N_Loop_Statement;
+
+ ----------------------------
+ -- Expand_Predicated_Loop --
+ ----------------------------
+
+ -- Note: the expander can handle generation of loops over predicated
+ -- subtypes for both the dynamic and static cases. Depending on what
+ -- we decide is allowed in Ada 2012 mode and/or extensions allowed
+ -- mode, the semantic analyzer may disallow one or both forms.
+
+ procedure Expand_Predicated_Loop (N : Node_Id) is
+ Loc : constant Source_Ptr := Sloc (N);
+ Isc : constant Node_Id := Iteration_Scheme (N);
+ LPS : constant Node_Id := Loop_Parameter_Specification (Isc);
+ Loop_Id : constant Entity_Id := Defining_Identifier (LPS);
+ Ltype : constant Entity_Id := Etype (Loop_Id);
+ Stat : constant List_Id := Static_Predicate (Ltype);
+ Stmts : constant List_Id := Statements (N);
+
+ begin
+ -- Case of iteration over non-static predicate, should not be possible
+ -- since this is not allowed by the semantics and should have been
+ -- caught during analysis of the loop statement.
+
+ if No (Stat) then
+ raise Program_Error;
+
+ -- If the predicate list is empty, that corresponds to a predicate of
+ -- False, in which case the loop won't run at all, and we rewrite the
+ -- entire loop as a null statement.
+
+ elsif Is_Empty_List (Stat) then
+ Rewrite (N, Make_Null_Statement (Loc));
+ Analyze (N);
+
+ -- For expansion over a static predicate we generate the following
+
+ -- declare
+ -- J : Ltype := min-val;
+ -- begin
+ -- loop
+ -- body
+ -- case J is
+ -- when endpoint => J := startpoint;
+ -- when endpoint => J := startpoint;
+ -- ...
+ -- when max-val => exit;
+ -- when others => J := Lval'Succ (J);
+ -- end case;
+ -- end loop;
+ -- end;
+
+ -- To make this a little clearer, let's take a specific example:
+
+ -- type Int is range 1 .. 10;
+ -- subtype L is Int with
+ -- predicate => L in 3 | 10 | 5 .. 7;
+ -- ...
+ -- for L in StaticP loop
+ -- Put_Line ("static:" & J'Img);
+ -- end loop;
+
+ -- In this case, the loop is transformed into
+
+ -- begin
+ -- J : L := 3;
+ -- loop
+ -- body
+ -- case J is
+ -- when 3 => J := 5;
+ -- when 7 => J := 10;
+ -- when 10 => exit;
+ -- when others => J := L'Succ (J);
+ -- end case;
+ -- end loop;
+ -- end;
+
+ else
+ Static_Predicate : declare
+ S : Node_Id;
+ D : Node_Id;
+ P : Node_Id;
+ Alts : List_Id;
+ Cstm : Node_Id;
+
+ function Lo_Val (N : Node_Id) return Node_Id;
+ -- Given static expression or static range, returns an identifier
+ -- whose value is the low bound of the expression value or range.
+
+ function Hi_Val (N : Node_Id) return Node_Id;
+ -- Given static expression or static range, returns an identifier
+ -- whose value is the high bound of the expression value or range.
+
+ ------------
+ -- Hi_Val --
+ ------------
+
+ function Hi_Val (N : Node_Id) return Node_Id is
+ begin
+ if Is_Static_Expression (N) then
+ return New_Copy (N);
+ else
+ pragma Assert (Nkind (N) = N_Range);
+ return New_Copy (High_Bound (N));
+ end if;
+ end Hi_Val;
+
+ ------------
+ -- Lo_Val --
+ ------------
+
+ function Lo_Val (N : Node_Id) return Node_Id is
+ begin
+ if Is_Static_Expression (N) then
+ return New_Copy (N);
+ else
+ pragma Assert (Nkind (N) = N_Range);
+ return New_Copy (Low_Bound (N));
+ end if;
+ end Lo_Val;
+
+ -- Start of processing for Static_Predicate
+
+ begin
+ -- Convert loop identifier to normal variable and reanalyze it so
+ -- that this conversion works. We have to use the same defining
+ -- identifier, since there may be references in the loop body.
+
+ Set_Analyzed (Loop_Id, False);
+ Set_Ekind (Loop_Id, E_Variable);
+
+ -- In most loops the loop variable is assigned in various
+ -- alternatives in the body. However, in the rare case when
+ -- the range specifies a single element, the loop variable
+ -- may trigger a spurious warning that is could be constant.
+ -- This warning might as well be suppressed.
+
+ Set_Warnings_Off (Loop_Id);
+
+ -- Loop to create branches of case statement
+
+ Alts := New_List;
+ P := First (Stat);
+ while Present (P) loop
+ if No (Next (P)) then
+ S := Make_Exit_Statement (Loc);
+ else
+ S :=
+ Make_Assignment_Statement (Loc,
+ Name => New_Occurrence_Of (Loop_Id, Loc),
+ Expression => Lo_Val (Next (P)));
+ Set_Suppress_Assignment_Checks (S);
+ end if;
+
+ Append_To (Alts,
+ Make_Case_Statement_Alternative (Loc,
+ Statements => New_List (S),
+ Discrete_Choices => New_List (Hi_Val (P))));
+
+ Next (P);
+ end loop;
+
+ -- Add others choice
+
+ S :=
+ Make_Assignment_Statement (Loc,
+ Name => New_Occurrence_Of (Loop_Id, Loc),
+ Expression =>
+ Make_Attribute_Reference (Loc,
+ Prefix => New_Occurrence_Of (Ltype, Loc),
+ Attribute_Name => Name_Succ,
+ Expressions => New_List (
+ New_Occurrence_Of (Loop_Id, Loc))));
+ Set_Suppress_Assignment_Checks (S);
+
+ Append_To (Alts,
+ Make_Case_Statement_Alternative (Loc,
+ Discrete_Choices => New_List (Make_Others_Choice (Loc)),
+ Statements => New_List (S)));
+
+ -- Construct case statement and append to body statements
+
+ Cstm :=
+ Make_Case_Statement (Loc,
+ Expression => New_Occurrence_Of (Loop_Id, Loc),
+ Alternatives => Alts);
+ Append_To (Stmts, Cstm);
+
+ -- Rewrite the loop
+
+ D :=
+ Make_Object_Declaration (Loc,
+ Defining_Identifier => Loop_Id,
+ Object_Definition => New_Occurrence_Of (Ltype, Loc),
+ Expression => Lo_Val (First (Stat)));
+ Set_Suppress_Assignment_Checks (D);
+
+ Rewrite (N,
+ Make_Block_Statement (Loc,
+ Declarations => New_List (D),
+ Handled_Statement_Sequence =>
+ Make_Handled_Sequence_Of_Statements (Loc,
+ Statements => New_List (
+ Make_Loop_Statement (Loc,
+ Statements => Stmts,
+ End_Label => Empty)))));
+
+ Analyze (N);
+ end Static_Predicate;
+ end if;
+ end Expand_Predicated_Loop;
+
+ ------------------------------
+ -- Make_Tag_Ctrl_Assignment --
+ ------------------------------
+
+ function Make_Tag_Ctrl_Assignment (N : Node_Id) return List_Id is
+ Asn : constant Node_Id := Relocate_Node (N);
+ L : constant Node_Id := Name (N);
+ Loc : constant Source_Ptr := Sloc (N);
+ Res : constant List_Id := New_List;
+ T : constant Entity_Id := Underlying_Type (Etype (L));
+
+ Comp_Asn : constant Boolean := Is_Fully_Repped_Tagged_Type (T);
+ Ctrl_Act : constant Boolean := Needs_Finalization (T)
+ and then not No_Ctrl_Actions (N);
+ Save_Tag : constant Boolean := Is_Tagged_Type (T)
+ and then not Comp_Asn
+ and then not No_Ctrl_Actions (N)
+ and then Tagged_Type_Expansion;
+ -- Tags are not saved and restored when VM_Target because VM tags are
+ -- represented implicitly in objects.
+
+ Next_Id : Entity_Id;
+ Prev_Id : Entity_Id;
+ Tag_Id : Entity_Id;
+
+ begin
+ -- Finalize the target of the assignment when controlled
+
+ -- We have two exceptions here:
+
+ -- 1. If we are in an init proc since it is an initialization more
+ -- than an assignment.
+
+ -- 2. If the left-hand side is a temporary that was not initialized
+ -- (or the parent part of a temporary since it is the case in
+ -- extension aggregates). Such a temporary does not come from
+ -- source. We must examine the original node for the prefix, because
+ -- it may be a component of an entry formal, in which case it has
+ -- been rewritten and does not appear to come from source either.
+
+ -- Case of init proc
+
+ if not Ctrl_Act then
+ null;
+
+ -- The left hand side is an uninitialized temporary object
+
+ elsif Nkind (L) = N_Type_Conversion
+ and then Is_Entity_Name (Expression (L))
+ and then Nkind (Parent (Entity (Expression (L)))) =
+ N_Object_Declaration
+ and then No_Initialization (Parent (Entity (Expression (L))))
+ then
+ null;
+
+ else
+ Append_To (Res,
+ Make_Final_Call
+ (Obj_Ref => Duplicate_Subexpr_No_Checks (L),
+ Typ => Etype (L)));
+ end if;
+
+ -- Save the Tag in a local variable Tag_Id
+
+ if Save_Tag then
+ Tag_Id := Make_Temporary (Loc, 'A');
+
+ Append_To (Res,
+ Make_Object_Declaration (Loc,
+ Defining_Identifier => Tag_Id,
+ Object_Definition => New_Reference_To (RTE (RE_Tag), Loc),
+ Expression =>
+ Make_Selected_Component (Loc,
+ Prefix => Duplicate_Subexpr_No_Checks (L),
+ Selector_Name =>
+ New_Reference_To (First_Tag_Component (T), Loc))));
+
+ -- Otherwise Tag_Id is not used
+
+ else
+ Tag_Id := Empty;
+ end if;
+
+ -- Save the Prev and Next fields on .NET/JVM. This is not needed on non
+ -- VM targets since the fields are not part of the object.
+
+ if VM_Target /= No_VM
+ and then Is_Controlled (T)
+ then
+ Prev_Id := Make_Temporary (Loc, 'P');
+ Next_Id := Make_Temporary (Loc, 'N');
+
+ -- Generate:
+ -- Pnn : Root_Controlled_Ptr := Root_Controlled (L).Prev;
+
+ Append_To (Res,
+ Make_Object_Declaration (Loc,
+ Defining_Identifier => Prev_Id,
+ Object_Definition =>
+ New_Reference_To (RTE (RE_Root_Controlled_Ptr), Loc),
+ Expression =>
+ Make_Selected_Component (Loc,
+ Prefix =>
+ Unchecked_Convert_To
+ (RTE (RE_Root_Controlled), New_Copy_Tree (L)),
+ Selector_Name =>
+ Make_Identifier (Loc, Name_Prev))));
+
+ -- Generate:
+ -- Nnn : Root_Controlled_Ptr := Root_Controlled (L).Next;
+
+ Append_To (Res,
+ Make_Object_Declaration (Loc,
+ Defining_Identifier => Next_Id,
+ Object_Definition =>
+ New_Reference_To (RTE (RE_Root_Controlled_Ptr), Loc),
+ Expression =>
+ Make_Selected_Component (Loc,
+ Prefix =>
+ Unchecked_Convert_To
+ (RTE (RE_Root_Controlled), New_Copy_Tree (L)),
+ Selector_Name =>
+ Make_Identifier (Loc, Name_Next))));
+ end if;
+
+ -- If the tagged type has a full rep clause, expand the assignment into
+ -- component-wise assignments. Mark the node as unanalyzed in order to
+ -- generate the proper code and propagate this scenario by setting a
+ -- flag to avoid infinite recursion.
+
+ if Comp_Asn then
+ Set_Analyzed (Asn, False);
+ Set_Componentwise_Assignment (Asn, True);
+ end if;
+
+ Append_To (Res, Asn);
+
+ -- Restore the tag
+
+ if Save_Tag then
+ Append_To (Res,
+ Make_Assignment_Statement (Loc,
+ Name =>
+ Make_Selected_Component (Loc,
+ Prefix => Duplicate_Subexpr_No_Checks (L),
+ Selector_Name =>
+ New_Reference_To (First_Tag_Component (T), Loc)),
+ Expression => New_Reference_To (Tag_Id, Loc)));
+ end if;
+
+ -- Restore the Prev and Next fields on .NET/JVM
+
+ if VM_Target /= No_VM
+ and then Is_Controlled (T)
+ then
+ -- Generate:
+ -- Root_Controlled (L).Prev := Prev_Id;
+
+ Append_To (Res,
+ Make_Assignment_Statement (Loc,
+ Name =>
+ Make_Selected_Component (Loc,
+ Prefix =>
+ Unchecked_Convert_To
+ (RTE (RE_Root_Controlled), New_Copy_Tree (L)),
+ Selector_Name =>
+ Make_Identifier (Loc, Name_Prev)),
+ Expression => New_Reference_To (Prev_Id, Loc)));
+
+ -- Generate:
+ -- Root_Controlled (L).Next := Next_Id;
+
+ Append_To (Res,
+ Make_Assignment_Statement (Loc,
+ Name =>
+ Make_Selected_Component (Loc,
+ Prefix =>
+ Unchecked_Convert_To
+ (RTE (RE_Root_Controlled), New_Copy_Tree (L)),
+ Selector_Name => Make_Identifier (Loc, Name_Next)),
+ Expression => New_Reference_To (Next_Id, Loc)));
+ end if;
+
+ -- Adjust the target after the assignment when controlled (not in the
+ -- init proc since it is an initialization more than an assignment).
+
+ if Ctrl_Act then
+ Append_To (Res,
+ Make_Adjust_Call
+ (Obj_Ref => Duplicate_Subexpr_Move_Checks (L),
+ Typ => Etype (L)));
+ end if;
+
+ return Res;
+
+ exception
+
+ -- Could use comment here ???
+
+ when RE_Not_Available =>
+ return Empty_List;
+ end Make_Tag_Ctrl_Assignment;
+
+end Exp_Ch5;