switch are
@option{-gnatwd} (implicit dereferencing),
@option{-gnatwh} (hiding),
+@option{-gnatw.h} (holes (gaps) in record layouts)
@option{-gnatwl} (elaboration warnings),
@option{-gnatw.o} (warn on values set by out parameters ignored)
and @option{-gnatwt} (tracking of deleted conditional code).
@cindex @option{-gnatwH} (@command{gcc})
This switch suppresses warnings on hiding declarations.
+@item -gnatw.h
+@emph{Activate warnings on holes/gaps in records.}
+@cindex @option{-gnatw.h} (@command{gcc})
+@cindex Record Representation (gaps)
+This switch activates warnings on component clauses in record
+representation clauses that leave holes (gaps) in the record layout.
+If this warning option is active, then record representation clauses
+should specify a contiguous layout, adding unused fill fields if needed.
+Note that @option{-gnatwa} does not affect the setting of this warning option.
+
+@item -gnatw.H
+@emph{Suppress warnings on holes/gaps in records.}
+@cindex @option{-gnatw.H} (@command{gcc})
+This switch suppresses warnings on component clauses in record
+representation clauses that leave holes (haps) in the record layout.
+
@item -gnatwi
@emph{Activate warnings on implementation units.}
@cindex @option{-gnatwi} (@command{gcc})
elsif Size /= No_Uint then
if VM_Target /= No_VM and then not GNAT_Mode then
+
-- Size clause is not handled properly on VM targets.
-- Display a warning unless we are in GNAT mode, in which
-- case this is useless.
+
Error_Msg_N
("?size clauses are ignored in this configuration", N);
end if;
Overlap_Check_Required : Boolean;
-- Used to keep track of whether or not an overlap check is required
+ Overlap_Detected : Boolean := False;
+ -- Set True if an overlap is detected
+
Ccount : Natural := 0;
-- Number of component clauses in record rep clause
procedure Check_Component_Overlap (C1_Ent, C2_Ent : Entity_Id) is
CC1 : constant Node_Id := Component_Clause (C1_Ent);
CC2 : constant Node_Id := Component_Clause (C2_Ent);
+
begin
if Present (CC1) and then Present (CC2) then
Error_Msg_Node_1 := Component_Name (CC1);
Error_Msg_N
("component& overlaps & #", Component_Name (CC1));
+ Overlap_Detected := True;
end if;
end;
end if;
if Present (Comp) then
Ccount := Ccount + 1;
+ -- We need a full overlap check if record positions non-monotonic
+
if Fbit <= Max_Bit_So_Far then
Overlap_Check_Required := True;
- else
- Max_Bit_So_Far := Lbit;
end if;
+ Max_Bit_So_Far := Lbit;
+
-- Check bit position out of range of specified size
if Has_Size_Clause (Rectype)
Error_Msg_NE
("component overlaps tag field of&",
Component_Name (CC), Rectype);
+ Overlap_Detected := True;
end if;
if Hbit < Lbit then
-- Skip overlap check if entity has no declaration node. This
-- happens with discriminants in constrained derived types.
- -- Probably we are missing some checks as a result, but that
- -- does not seem terribly serious ???
+ -- Possibly we are missing some checks as a result, but that
+ -- does not seem terribly serious.
if No (Declaration_Node (C1_Ent)) then
goto Continue_Main_Component_Loop;
else
Citem := First (Component_Items (Clist));
-
while Present (Citem) loop
if Nkind (Citem) = N_Component_Declaration then
C2_Ent := Defining_Identifier (Citem);
end Overlap_Check2;
end if;
+ -- The following circuit deals with warning on record holes (gaps). We
+ -- skip this check if overlap was detected, since it makes sense for the
+ -- programmer to fix this illegality before worrying about warnings.
+
+ if not Overlap_Detected and Warn_On_Record_Holes then
+ Record_Hole_Check : declare
+ Decl : constant Node_Id := Declaration_Node (Base_Type (Rectype));
+ -- Full declaration of record type
+
+ procedure Check_Component_List
+ (CL : Node_Id;
+ Sbit : Uint;
+ DS : List_Id);
+ -- Check component list CL for holes. The starting bit should be
+ -- Sbit. which is zero for the main record component list and set
+ -- appropriately for recursive calls for variants. DS is set to
+ -- a list of discriminant specifications to be included in the
+ -- consideration of components. It is No_List if none to consider.
+
+ --------------------------
+ -- Check_Component_List --
+ --------------------------
+
+ procedure Check_Component_List
+ (CL : Node_Id;
+ Sbit : Uint;
+ DS : List_Id)
+ is
+ Compl : Integer;
+
+ begin
+ Compl := Integer (List_Length (Component_Items (CL)));
+
+ if DS /= No_List then
+ Compl := Compl + Integer (List_Length (DS));
+ end if;
+
+ declare
+ Comps : array (Natural range 0 .. Compl) of Entity_Id;
+ -- Gather components (zero entry is for sort routine)
+
+ Ncomps : Natural := 0;
+ -- Number of entries stored in Comps (starting at Comps (1))
+
+ Citem : Node_Id;
+ -- One component item or discriminant specification
+
+ Nbit : Uint;
+ -- Starting bit for next component
+
+ CEnt : Entity_Id;
+ -- Component entity
+
+ Variant : Node_Id;
+ -- One variant
+
+ function Lt (Op1, Op2 : Natural) return Boolean;
+ -- Compare routine for Sort
+
+ procedure Move (From : Natural; To : Natural);
+ -- Move routine for Sort
+
+ package Sorting is new GNAT.Heap_Sort_G (Move, Lt);
+
+ --------
+ -- Lt --
+ --------
+
+ function Lt (Op1, Op2 : Natural) return Boolean is
+ begin
+ return Component_Bit_Offset (Comps (Op1))
+ <
+ Component_Bit_Offset (Comps (Op2));
+ end Lt;
+
+ ----------
+ -- Move --
+ ----------
+
+ procedure Move (From : Natural; To : Natural) is
+ begin
+ Comps (To) := Comps (From);
+ end Move;
+
+ begin
+ -- Gather discriminants into Comp
+
+ if DS /= No_List then
+ Citem := First (DS);
+ while Present (Citem) loop
+ if Nkind (Citem) = N_Discriminant_Specification then
+ declare
+ Ent : constant Entity_Id :=
+ Defining_Identifier (Citem);
+ begin
+ if Ekind (Ent) = E_Discriminant then
+ Ncomps := Ncomps + 1;
+ Comps (Ncomps) := Ent;
+ end if;
+ end;
+ end if;
+
+ Next (Citem);
+ end loop;
+ end if;
+
+ -- Gather component entities into Comp
+
+ Citem := First (Component_Items (CL));
+ while Present (Citem) loop
+ if Nkind (Citem) = N_Component_Declaration then
+ Ncomps := Ncomps + 1;
+ Comps (Ncomps) := Defining_Identifier (Citem);
+ end if;
+
+ Next (Citem);
+ end loop;
+
+ -- Now sort the component entities based on the first bit.
+ -- Note we already know there are no overlapping components.
+
+ Sorting.Sort (Ncomps);
+
+ -- Loop through entries checking for holes
+
+ Nbit := Sbit;
+ for J in 1 .. Ncomps loop
+ CEnt := Comps (J);
+ Error_Msg_Uint_1 := Component_Bit_Offset (CEnt) - Nbit;
+
+ if Error_Msg_Uint_1 > 0 then
+ Error_Msg_NE
+ ("?^-bit gap before component&",
+ Component_Name (Component_Clause (CEnt)), CEnt);
+ end if;
+
+ Nbit := Component_Bit_Offset (CEnt) + Esize (CEnt);
+ end loop;
+
+ -- Process variant parts recursively if present
+
+ if Present (Variant_Part (CL)) then
+ Variant := First (Variants (Variant_Part (CL)));
+ while Present (Variant) loop
+ Check_Component_List
+ (Component_List (Variant), Nbit, No_List);
+ Next (Variant);
+ end loop;
+ end if;
+ end;
+ end Check_Component_List;
+
+ -- Start of processing for Record_Hole_Check
+
+ begin
+ declare
+ Sbit : Uint;
+
+ begin
+ if Is_Tagged_Type (Rectype) then
+ Sbit := UI_From_Int (System_Address_Size);
+ else
+ Sbit := Uint_0;
+ end if;
+
+ if Nkind (Decl) = N_Full_Type_Declaration
+ and then Nkind (Type_Definition (Decl)) = N_Record_Definition
+ then
+ Check_Component_List
+ (Component_List (Type_Definition (Decl)),
+ Sbit,
+ Discriminant_Specifications (Decl));
+ end if;
+ end;
+ end Record_Hole_Check;
+ end if;
+
-- For records that have component clauses for all components, and whose
-- size is less than or equal to 32, we need to know the size in the
-- front end to activate possible packed array processing where the
begin
-- In the case of functions with unconstrained result subtypes,
- -- add a 3-state formal indicating whether the return object is
- -- allocated by the caller (0), or should be allocated by the
- -- callee on the secondary stack (1) or in the global heap (2).
- -- For the moment we just use Natural for the type of this formal.
- -- Note that this formal isn't usually needed in the case where
- -- the result subtype is constrained, but it is needed when the
- -- function has a tagged result, because generally such functions
- -- can be called in a dispatching context and such calls must be
- -- handled like calls to a class-wide function.
+ -- add a 4-state formal indicating whether the return object is
+ -- allocated by the caller (1), or should be allocated by the
+ -- callee on the secondary stack (2), in the global heap (3), or
+ -- in a user-defined storage pool (4). For the moment we just use
+ -- Natural for the type of this formal. Note that this formal
+ -- isn't usually needed in the case where the result subtype is
+ -- constrained, but it is needed when the function has a tagged
+ -- result, because generally such functions can be called in a
+ -- dispatching context and such calls must be handled like calls
+ -- to a class-wide function.
if not Is_Constrained (Underlying_Type (Result_Subt))
or else Is_Tagged_Type (Underlying_Type (Result_Subt))
projects / platform / upstream / gcc.git / commitdiff