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Text File | 1996-09-28 | 85KB | 2,296 lines

------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- S E M _ A G G R -- -- -- -- B o d y -- -- -- -- $Revision: 1.79 $ -- -- -- -- Copyright (c) 1992,1993,1994 NYU, All Rights Reserved -- -- -- -- 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 2, 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 COPYING. If not, write -- -- to the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. -- -- -- ------------------------------------------------------------------------------ with Atree; use Atree; with Einfo; use Einfo; with Elists; use Elists; with Errout; use Errout; with Expander; use Expander; with Exp_Util; use Exp_Util; with Features; use Features; with Freeze; use Freeze; with Itypes; use Itypes; with Namet; use Namet; with Nmake; use Nmake; with Nlists; use Nlists; with Opt; use Opt; with Rtsfind; use Rtsfind; with Sem; use Sem; with Sem_Ch3; use Sem_Ch3; with Sem_Ch5; use Sem_Ch5; with Sem_Eval; use Sem_Eval; with Sem_Res; use Sem_Res; with Sem_Util; use Sem_Util; with Sem_Type; use Sem_Type; with Sinfo; use Sinfo; with Snames; use Snames; with Stringt; use Stringt; with Stand; use Stand; with Tbuild; use Tbuild; with Uintp; use Uintp; with System.Parameters; package body Sem_Aggr is ------------------------------------------------------ -- Subprogram Specs for RECORD AGGREGATE Processing -- ------------------------------------------------------ procedure Resolve_Record_Aggregate (N : Node_Id; Typ : Entity_Id); -- This procedure performs all the semantic checks required for record -- aggregates. This procedure assumes that the others choice is by -- itself and appears last in the aggregate, if it is present. This -- test was previously done is Resolve_Aggregate. -- -- N is the N_Aggregate node. -- Typ is the record type for the aggregate resolution -- -- While performing the semantic checks, this procedure -- builds a new Component_Association_List where each record field -- appears alone in a Component_Choice_List along with its corresponding -- expression. The record fields in the Component_Association_List -- appear in the same order in which they appear in the record type Typ. -- -- Once this new Component_Association_List is built and all the -- semantic checks performed, the original aggregate subtree is replaced -- with the new named record aggregate just built. Note that the subtree -- substitution is performed with Rewrite_Substitute_Tree so as to be -- able to retrieve the original aggregate. -- -- The aggregate subtree manipulation performed by Resolve_Record_Aggregate -- yields the aggregate format expected by Gigi. Typically, this kind of -- tree manipulations are done in the expander. However, because the -- semantic checks that need to be performed on record aggregates really -- go hand in hand with the record aggreagate normalization, the aggregate -- subtree transformation is performed during resolution rather than -- expansion. Had we decided otherwise we would have had to duplicate -- most of the code in the expansion procedure Expand_Record_Aggregate. -- Note, however, that all the expansion concerning aggegates for tagged -- records is done in Expand_Record_Aggregate. -- -- The algorithm of Resolve_Record_Aggregate proceeds as follows: -- -- 1. Make sure that the record type against which the record aggregate -- has to be resolved is not abstract. Furthermore if the type is -- a null aggregate make sure the input aggregate N is also null. -- -- 2. Verify that the structure of the aggregate is that of a record -- aggregate. Specifically, look for component associations and ensure -- that each choice list only has identifiers or the N_Others_Choice -- node. Note that at this point Analyze_Aggregate has already made -- sure that the N_Others_Choice occurs last and by itself. -- -- 3. If Typ contains discriminants, the values for each discriminant -- is looked for. If the record type Typ has variants, we check -- that the expressions corresponding to each discriminant ruling -- the (possibly nested) variant parts of Typ, are static. This -- allows us to determine the variant parts to which the rest of -- the aggregate must conform. The names of discriminants with their -- values are saved in a new association list, New_Assoc_List which -- is later augmented with the names and values of the remaining -- components in the record type. -- -- During this phase we also make sure that every discriminant is -- assigned exactly one value. Note that when several values -- for a given discriminant are found, semantic processing continues -- looking for further errors. In this case it's the first -- discriminant value found which we will be recorded. -- -- IMPORTANT NOTE: For derived tagged types this procedure expects -- First_Discriminant and Next_Discriminant to give the correct list -- of discriminants, in the correct order. -- -- 4. After all the discriminant values have been gathered, we can -- set the Etype of the record aggregate. If Typ contains no -- discriminants this is straightforward: the Etype of N is just -- Typ, otherwise a new implicit constrained subtype of Typ is -- built to be the Etype of N. -- -- 5. Gather the remaining record components according to the discriminant -- values. This involves recursively traversing the record type -- structure to see what variants are selected by the given discriminant -- values. This processing is a little more convoluted if Typ is a -- derived tagged types since we need to retrieve the record structure -- of all the ancestors of Typ. -- -- 6. After gathering the record components we look for their values -- in the record aggregate and emit appropriate error messages -- should we not find such values or should they be duplicated. -- -- 7. We then make sure no illegal component names appear in the -- record aggegate and make sure that the type of the record -- components appearing in a same choice list is the same. -- Finally we ensure that the others choice, if present, is -- used to provide the value of at least a record component. -- -- 8. The original aggregate node is replaced with the new named -- aggregate built in steps 3 through 6, as explained earlier. -- -- Given the complexity of record aggregate resolution, the primary -- goal of this routine is clarity and simplicity rather than execution -- and storage efficiency. If there are only positional components in the -- aggregate the running time is linear. If there are associations -- the running time is still linear as long as the order of the -- associations is not too far off the order of the components in the -- record type. If this is not the case the running time is at worst -- quadratic in the size of the association list. procedure Gather_Components (Comp_List : Node_Id; Governed_By : List_Id; Into : Elist_Id; Report_Errors : out Boolean); -- The purpose of this procedure is to gather the valid components -- in a record type according to the values of its discriminants. -- Specifically: -- -- Comp_List is an N_Component_List node. -- -- Governed_By is a list of N_Component_Association nodes, -- where each choice list contains the name of a discriminant and -- the expression field gives its value. The values of the -- discriminants governing the (possibly nested) variant parts in -- Comp_List are found in this Component_Association List. -- -- Into is the list where the valid components are appended. -- Note that Into need not be an Empty list. If it's not, components -- are attached to its tail. -- -- Report_Errors is set to True if the values of the discriminants -- are non-static. ----------------------------------------------------- -- Subprogram Specs for ARRAY AGGREGATE Processing -- ----------------------------------------------------- function Resolve_Array_Aggregate (N : Node_Id; Index : Node_Id; Component_Typ : Entity_Id; Others_Allowed : Boolean) return Boolean; -- This procedure performs the semantic checks for an array aggregate. -- True is returned if the aggregate resolution succeeds. -- The procedure works by recursively checking each nested aggregate. -- Specifically, after checking a sub-aggreate nested at the i-th level -- we recursively check all the subaggregates at the i+1-st level (if any). -- -- N is the current N_Aggregate node to be checked. -- -- Index is the index node corresponding to the array sub-aggregate that -- we are currently checking (RM 4.3.3 (8)). it is the node giving the -- applicable index constraint if any (RM 4.3.3 (10)). -- It "is a constraint provided by certain contexts [...] that can be -- used to determine the bounds of the array value specified by the -- aggregate". If Others_Allowed below is False there is no applicable -- index constraint. -- -- Component_Typ is the array component type. -- -- Others_Allowed indicates whether an others choice is allowed -- in the context where the top-level aggregate appeared. -- -- The algorithm of Resolve_Array_Aggregate proceeds as follows: -- -- 1. Make sure that the others choice, if present, is by itself -- and appears last in the sub-aggregate. This test has already been -- performed during the analysis phase. If the sub-aggregate format was -- found to be incorrect during analysis, the Etype of the sub-aggregate -- is set to Any_Type. Also check that we do not have positional and -- named components in the array sub-aggregate (unless the named -- association is an others choice). Finally if an others choice is -- present, make sure it is allowed in the aggregate contex. -- -- 2. If the array sub-aggregate contains discrete_choices: -- -- (A) Verify their validity. Specifically verify that: -- -- (a) If a null range is present it must be the only possible -- choice in the array aggregate. -- -- (b) Ditto for a non static range. -- -- (c) Ditto for a non static expression. -- -- In addition this step analyzes and resolves each discrete_choice, -- making sure that its type is the type of the corresponding Index. -- If we are not at the lowest array aggregate level (in the case of -- multi-dimensional aggregates) then invoke Resolve_Array_Aggregate -- recursively on each component expression. Otherwise resolve -- the bottom level component expressions against the expected -- component type. -- -- (B) Determine the bounds of the sub-aggregate and lowest and -- highest choice values. -- -- 3. For positional aggregates: -- -- (A) Loop over the component expressions either recursively invoking -- Resolve_Array_Aggregate on each of these for multi-dimensional -- array aggregates or resolving the bottom level component -- expressions against the expected component type. -- -- (B) Determine the bounds of the positional sub-aggregates. -- -- 4. Try to determine statically whether the evaluation of the array -- sub-aggregate raises Constraint_Error. If yes emit proper -- warnings. The precise checks are the following: -- -- (A) Check that the index range defined by aggregate bounds is -- compatible with corresponding index subtype. -- We also check against the base type. In fact it could be that -- Low/High bounds of the base type are static whereas those of -- the index subtype are not. Thus if we can statically catch -- a problem with respect to the base type we are guaranteed -- that the same problem will arise with the index subtype -- -- (B) If we are dealing with a named aggregate containing an others -- choice and at least one discrete choice then make sure the range -- specified by the discrete choices does not overflow the -- aggregate bounds. -- -- (C) If we are dealing with a positional aggregate with an others -- choice make sure the number of positional elements specified -- does not overflow the aggregate bounds. -- -- Finally construct an N_Range node giving the sub-aggregate bounds. -- Set the Aggregate_Bounds field of the sub-aggregate to be this -- N_Range. The routine Array_Aggr_Subtype below uses such N_Ranges -- to build the appropriate aggregate subtype. Aggregate_Bounds -- information is needed during expansion. function Array_Aggr_Subtype (N : Node_Id; Typ : Node_Id) return Entity_Id; -- This routine returns the type or subtype of an array aggregate. -- -- N is the array aggregate node whose type we return. -- -- Typ is the context type in which N occurs. -- -- This routine creates an implicit array subtype whose bouds are -- those defined by the aggregate. When this routine is invoked -- Resolve_Array_Aggregate has already processed aggregate N. Thus the -- Aggregate_Bounds of each sub-aggregate, is an N_Range node giving the -- sub-aggregate bounds. When building the aggegate itype, this function -- traverses the array aggregate N collecting such Aggregate_Bounds and -- constructs the proper array aggregate itype. -- -- Note that in the case of multidimensional aggregates each inner -- sub-aggregate corresponding to a given array dimension, may provide a -- different bounds. If it is possible to determine statically that -- some sub-aggregates corresponding to the same index do not have the -- same bounds, then a warning is emitted. If such check is not possible -- statically (because some sub-aggregate bounds are dynamic expressions) -- then this job is left to the expander. In all cases the particular -- bounds that this function will chose for a given dimension is the first -- N_Range node for a sub-aggregate corresponding to that dimension. function Constraint_Err (N : Node_Id) return Boolean; -- Returns True if N is an N_Raise_Constraint_Error node or its -- Raises_Constraint_Error flag is set. function Raises_CE (N : Node_Id; Dim : Pos) return Boolean; -- Checks whether the array aggregate N contains a sub-aggreage whose -- Raises_Constraint_Error flag is set. Returns True if yes. Dim is the -- number of indices of N. It is needed to figure out the structure of N -- (ie how many sub-aggregates it has). procedure Make_String_Into_Aggregate (N : Node_Id); -- A string literal can appear in a context in which a one dimensional -- array of characters is expected. This procedure simply rewrites the -- string as an aggregate, prior to resolution. ----------------------- -- Resolve_Aggregate -- ----------------------- procedure Resolve_Aggregate (N : Node_Id; Typ : Entity_Id) is Pkind : constant Node_Kind := Nkind (Parent (N)); begin -- Make sure that the others choice is by itself and appears -- last in the aggregate, if it's present. This test is actually -- not performed here. The code for this is in Analyze_Aggregate. -- What Analyze_Aggregate does is to set the Etype of the record -- aggregate to be Any_Type to signal that there was a problem -- with an others choice. if Etype (N) = Any_Type then Set_Etype (N, Any_Composite); elsif Is_Limited_Type (Typ) then Error_Msg_N ("aggregate type cannot be limited", N); elsif Is_Class_Wide_Type (Typ) then Error_Msg_N ("aggregate cannot be of a class-wide type", N); elsif Is_Record_Type (Typ) then Resolve_Record_Aggregate (N, Typ); elsif Is_Array_Type (Typ) then Array_Aggregate : declare Aggr_Subtyp : Entity_Id; Aggr_Resolved : Boolean; begin -- In the following we determine whether an others choice is -- allowed inside the array aggregate. The test checks the context -- in which the array aggregate occurs. If the context does not -- permit it, or the aggregate type is unconstrained, an others -- choice is not allowed. -- -- Note that there is no node for Explicit_Actual_Parameter. -- To test for this context we therefore have to test for node -- N_Parameter_Association which itself appears only if there is a -- formal parameter. Consequently we also need to test for -- N_Procedure_Call_Statement or N_Function_Call. if Is_Constrained (Typ) and then (Pkind = N_Assignment_Statement or else Pkind = N_Parameter_Association or else Pkind = N_Function_Call or else Pkind = N_Procedure_Call_Statement or else Pkind = N_Generic_Association or else Pkind = N_Formal_Object_Declaration or else Pkind = N_Return_Statement or else Pkind = N_Object_Declaration or else Pkind = N_Component_Declaration or else Pkind = N_Parameter_Specification or else Pkind = N_Qualified_Expression or else Pkind = N_Aggregate or else Pkind = N_Component_Association) then Aggr_Resolved := Resolve_Array_Aggregate (N, Index => First_Index (Typ), Component_Typ => Component_Type (Typ), Others_Allowed => True); else Aggr_Resolved := Resolve_Array_Aggregate (N, Index => First_Index (Typ), Component_Typ => Component_Type (Typ), Others_Allowed => False); end if; if not Aggr_Resolved then Aggr_Subtyp := Any_Composite; else Aggr_Subtyp := Array_Aggr_Subtype (N, Typ); -- If we can determine statically that the evaluation of the -- array aggregate raises Constraint_Error, then replace the -- aggregate with an N_Raise_Constraint_Error node, but set the -- Etype to the Aggr_Subtyp computed above for Gigi. if Raises_CE (N, Number_Dimensions (Typ)) then Rewrite_Substitute_Tree (N, Make_Raise_Constraint_Error (Sloc (N))); Set_Raises_Constraint_Error (N); Set_Analyzed (N, True); end if; end if; Set_Etype (N, Aggr_Subtyp); end Array_Aggregate; else Error_Msg_N ("illegal context for aggregate", N); end if; end Resolve_Aggregate; --------------------------------- -- Resolve_Extension_Aggregate -- --------------------------------- -- There are two cases to consider: -- a) If the ancestor part is a type mark, the components needed are -- the difference between the components of the expected type and the -- components of the given type mark. -- b) If the ancestor part is an expression, it must be unambiguous, -- and once we have its type we can also compute the needed components -- as in the previous case. In both cases, if the ancestor type is not -- the immediate ancestor, we have to build this ancestor recursively. -- In both cases discriminants of the ancestor type do not play a -- role in the resolution of the needed components, because inherited -- discriminants cannot be used in a type extension. As a result we can -- compute independently the list of components of the ancestor type and -- of the expected type. procedure Resolve_Extension_Aggregate (N : Node_Id; Typ : Entity_Id) is A : constant Node_Id := Ancestor_Part (N); A_Type : Entity_Id; I : Interp_Index; It : Interp; Imm_Type : Entity_Id; function Valid_Ancestor_Type return Boolean; -- Verify that the type of the ancestor part is a non-private ancestor -- of the expected type. function Valid_Ancestor_Type return Boolean is Imm_Type : Entity_Id := Base_Type (Typ); begin while Is_Derived_Type (Imm_Type) and then Etype (Imm_Type) /= Base_Type (A_Type) loop Imm_Type := Etype (Base_Type (Imm_Type)); end loop; if Etype (Imm_Type) /= Base_Type (A_Type) then Error_Msg_NE ("expect ancestor type of &", A, Typ); return false; else return true; end if; end Valid_Ancestor_Type; begin if not Is_Tagged_Type (Typ) then Error_Msg_N ("type of extension aggregate must be tagged", N); return; elsif Is_Limited_Type (Typ) then Error_Msg_N ("aggregate type cannot be limited", N); return; elsif Is_Class_Wide_Type (Typ) then Error_Msg_N ("aggregate cannot be of a class-wide type", N); return; end if; if Is_Entity_Name (A) and then Is_Type (Entity (A)) then A_Type := Entity (A); Imm_Type := Base_Type (Typ); if Valid_Ancestor_Type then Resolve_Record_Aggregate (N, Typ); end if; elsif Nkind (A) /= N_Aggregate then if Is_Overloaded (A) then A_Type := Any_Type; Get_First_Interp (A, I, It); while Present (It.Typ) loop if Is_Tagged_Type (It.Typ) and then not Is_Limited_Type (It.Typ) then if A_Type /= Any_Type then Error_Msg_N ("cannot resolve expression", A); return; else A_Type := It.Typ; end if; end if; Get_Next_Interp (I, It); end loop; if A_Type = Any_Type then Error_Msg_N ("ancestor part must be non-limited tagged type", A); return; end if; else A_Type := Etype (A); end if; if Valid_Ancestor_Type then Resolve (A, A_Type); Resolve_Record_Aggregate (N, Typ); end if; else Error_Msg_N (" No unique type for this aggregate", A); end if; end Resolve_Extension_Aggregate; ------------------------------ -- Resolve_Record_Aggregate -- ------------------------------ procedure Resolve_Record_Aggregate (N : Node_Id; Typ : Entity_Id) is Expr : Node_Id; Record_Def : Node_Id; Positional_Expr : Node_Id; Assoc : Node_Id; -- N_Component_Association node belonging to the input aggregate N New_Assoc_List : List_Id := New_List; New_Assoc : Node_Id; -- New_Assoc_List is the newly built list of N_Component_Association -- nodes. New_Assoc is one such N_Component_Association node in it. -- Please note that while Assoc and New_Assoc contain the same -- kind of nodes, they are used to iterate over two different -- N_Component_Association lists. New_Aggregate : Node_Id := New_Copy (N); Component : Entity_Id; Component_Elmt : Elmt_Id; Components : Elist_Id := New_Elmt_List; -- Components is the list of the record components whose value must -- be provided in the aggregate. This list does include discriminants. Next_Expr : Node_Id; Others_Etype : Entity_Id := Empty; -- This variable is used to save the Etype of the last record component -- that takes its value from the others choice. Its purpose is: -- -- (a) make sure the others choice is useful -- -- (b) make sure the type of all the components whose value is -- subsumed by the others choice are the same. -- -- This variable is updated as a side effect of function Get_Value procedure Add_Association (Component : Entity_Id; Expr : Node_Id); -- Builds a new N_Component_Association node which associates -- Component to expression Expr and adds it to the new association -- list New_Assoc_List being built. function Get_Value (Compon : Node_Id; From : List_Id; Consider_Others_Choice : Boolean := False) return Node_Id; -- Given a record component stored in parameter Compon, the -- following function returns its value as it appears in the list -- From, which is a list of N_Component_Association nodes. If no -- component association has a choice for the searched component, -- the value provided by the others choice is returned, if there -- is one and Consider_Others_Choice is set to true. Otherwise -- Empty is returned. If there is more than one component association -- giving a value for the searched record component, an error message -- is emitted and the first found value is returned. -- -- If Consider_Others_Choice is set and the returned expression comes -- from the others choice, then Others_Etype is set as a side effect. -- An error message is emitted if the components taking their value -- from the others choice do not have same type. function Replace_Discriminants (In_Type : Entity_Id) return Entity_Id; -- In_Type is a type or subtype. If In_Type is a record subtype or an -- array subtype, a new Itype is created and returned. This Itype is -- attached to the aggregate node N. It is a copy of In_Type except -- that every occurrence of a record discriminant of the original -- record aggregate type Typ is replaced with its corresponding value -- as given by the record aggregate. -- -- Note that the Itype is created only if there is at least one such -- discriminant in subtype In_Type. Otherwise In_Type is returned. -- For example consider the following code: -- -- type rec (D : integer) is record -- F : String (1..D); -- end record; -- -- X : rec := (D => 3, "abc"); -- -- When analyzing the record aggregate, the Etype initially found for -- field F is String (1 .. D). However the Etype of "abc" must be -- String (1..3). Replace_Discriminants carries out precisely this -- transformation, i.e. in this case -- -- Replace_Discriminants (String (1..D)) -- -- returns -- -- String (1..3). -- -- Note that this function begins creating an Itype, before it knows -- whether it will be useful or not. If the Itype is not needed, that -- storage is wasted. --------------------- -- Add_Association -- --------------------- procedure Add_Association (Component : Entity_Id; Expr : Node_Id) is New_Assoc : Node_Id; Choice_List : List_Id := New_List; begin Append (New_Occurrence_Of (Component, Sloc (Expr)), Choice_List); New_Assoc := Make_Component_Association (Sloc (Expr), Choices => Choice_List, Expression => Expr); Append (New_Assoc, New_Assoc_List); end Add_Association; --------------- -- Get_Value -- --------------- function Get_Value (Compon : Node_Id; From : List_Id; Consider_Others_Choice : Boolean := False) return Node_Id is Assoc : Node_Id; Expr : Node_Id := Empty; Selector_Name : Node_Id; New_Expr : Node_Id; begin if Present (From) then Assoc := First (From); else return Empty; end if; while Present (Assoc) loop Selector_Name := First (Choices (Assoc)); while Present (Selector_Name) loop if Nkind (Selector_Name) = N_Others_Choice then if Consider_Others_Choice and then No (Expr) then if Present (Others_Etype) and then Base_Type (Others_Etype) /= Base_Type (Etype (Compon)) then Error_Msg_N ("components in OTHERS choice must " & "have same type", Selector_Name); end if; Others_Etype := Etype (Compon); New_Expr := New_Copy_Tree (Expression (Assoc)); Save_Interps (Expression (Assoc), New_Expr); return New_Expr; end if; elsif Chars (Compon) = Chars (Selector_Name) then if No (Expr) then Expr := Expression (Assoc); else Error_Msg_NE ("more than one value supplied for &", Selector_Name, Compon); end if; end if; Selector_Name := Next (Selector_Name); end loop; Assoc := Next (Assoc); end loop; return Expr; end Get_Value; --------------------------- -- Replace_Discriminants -- --------------------------- function Replace_Discriminants (In_Type : Entity_Id) return Entity_Id is New_Expr_List : Elist_Id; Discrim_Constraint : Elmt_Id; Index_Type : Entity_Id; Old_Index : Node_Id; New_Index : Node_Id; New_Index_List : List_Id; Old_Expr : Node_Id; New_Expr : Node_Id; Low_Expr : Node_Id; High_Expr : Node_Id; Itype : Entity_Id; Need_To_Create_Itype : Boolean := False; begin -- In the following code N refers to the input aggregate node and Typ -- its type. These are the parameters of Resolve_Record_Aggregate. if not Has_Discriminants (Typ) or else (Ekind (In_Type) /= E_Record_Subtype and then Ekind (In_Type) /= E_Array_Subtype) then return In_Type; end if; if Ekind (In_Type) = E_Record_Subtype and then Has_Discriminants (In_Type) then New_Expr_List := New_Elmt_List; Discrim_Constraint := First_Elmt (Discriminant_Constraint (In_Type)); while Present (Discrim_Constraint) loop Old_Expr := Node (Discrim_Constraint); if Nkind (Old_Expr) = N_Identifier and then Ekind (Entity (Old_Expr)) = E_Discriminant then Need_To_Create_Itype := True; New_Expr := Get_Value (Old_Expr, From => New_Assoc_List); pragma Assert (Present (New_Expr)); Append_Elmt (New_Expr, New_Expr_List); else Append_Elmt (Old_Expr, New_Expr_List); end if; Discrim_Constraint := Next_Elmt (Discrim_Constraint); end loop; if not Need_To_Create_Itype then return In_Type; end if; Itype := New_Itype (E_Record_Subtype, N); Set_Etype (Itype, Base_Type (In_Type)); Set_Esize (Itype, Esize (In_Type)); Set_Discriminant_Constraint (Itype, New_Expr_List); Set_Is_Tagged_Type (Itype, Is_Tagged_Type (In_Type)); Set_Has_Discriminants (Itype); Set_Is_Constrained (Itype); Set_First_Entity (Itype, First_Entity (In_Type)); Set_Last_Entity (Itype, Last_Entity (In_Type)); Set_Has_Tasks (Itype, Has_Tasks (In_Type)); Set_Depends_On_Private (Itype, Depends_On_Private (In_Type)); Set_Has_Controlled (Itype, Has_Controlled (In_Type)); if Is_Tagged_Type (In_Type) then Set_Access_Disp_Table (Itype, Access_Disp_Table (In_Type)); Set_Is_Controlled (Itype, Is_Controlled (In_Type)); end if; return Itype; elsif Ekind (In_Type) = E_Array_Subtype then New_Index_List := New_List; Old_Index := First_Index (In_Type); while Present (Old_Index) loop New_Index := New_Copy_Tree (Old_Index); if Nkind (New_Index) = N_Range then Set_Etype (New_Index, Base_Type (Etype (Old_Index))); Get_Index_Bounds (New_Index, Low_Expr, High_Expr); Old_Expr := Low_Expr; for J in 1 .. 2 loop if Nkind (Old_Expr) = N_Identifier and then Ekind (Entity (Old_Expr)) = E_Discriminant then Need_To_Create_Itype := True; New_Expr := Get_Value (Old_Expr, From => New_Assoc_List); pragma Assert (Present (New_Expr)); if J = 1 then Set_Low_Bound (New_Index, New_Copy_Tree (New_Expr)); else Set_High_Bound (New_Index, New_Copy_Tree (New_Expr)); end if; end if; Old_Expr := High_Expr; end loop; -- Create anonymous index type for range. Index_Type := New_Itype (Subtype_Kind (Ekind (Etype (New_Index))), N); Set_Etype (Index_Type, Etype (New_Index)); if Is_Character_Type (Etype (New_Index)) then Set_Is_Character_Type (Index_Type, True); end if; Set_Esize (Index_Type, Esize (Etype (New_Index))); Set_Alignment_Clause (Index_Type, Alignment_Clause (Etype (New_Index))); Set_Scalar_Range (Index_Type, New_Index); Set_Etype (New_Index, Index_Type); end if; Append (New_Index, To => New_Index_List); Old_Index := Next_Index (Old_Index); end loop; if not Need_To_Create_Itype then return In_Type; end if; Itype := New_Itype (E_Array_Subtype, N); Set_Is_Constrained (Itype); Set_Etype (Itype, Base_Type (In_Type)); Set_Esize (Itype, Esize (In_Type)); Set_First_Index (Itype, First (New_Index_List)); Set_Component_Type (Itype, Replace_Discriminants (In_Type => Component_Type (In_Type))); Set_Has_Tasks (Itype, Has_Tasks (In_Type)); Set_Has_Controlled (Itype, Has_Controlled (In_Type)); Set_Depends_On_Private (Itype, Depends_On_Private (In_Type)); return Itype; end if; return In_Type; end Replace_Discriminants; -- Start processing for Resolve_Record_Aggregate begin -- New Aggregate eventually replaces the aggregate being resolved. It -- is initialized here, and attached to the tree explicitly to enforce -- the rule that a tree fragment should never be analyzed or resolved -- unless it is attached to the current compilation unit. Set_Component_Associations (New_Aggregate, New_Assoc_List); Set_Parent (New_Aggregate, Parent (N)); -- STEP 1: abstract type and null record verification if Is_Abstract (Typ) then Error_Msg_N ("type of aggregate cannot be abstract", N); end if; if No (First_Entity (Typ)) and then Null_Record_Present (N) then Set_Etype (N, Typ); return; elsif Present (First_Entity (Typ)) and then Null_Record_Present (N) and then not Is_Tagged_Type (Typ) then Error_Msg_N ("record aggregate cannot be null", N); return; elsif No (First_Entity (Typ)) then Error_Msg_N ("record aggregate must be null", N); return; end if; -- STEP 2: Verify aggregate structure Step_2 : declare Selector_Name : Node_Id; Bad_Aggregate : Boolean := False; begin if Present (Component_Associations (N)) then Assoc := First (Component_Associations (N)); else Assoc := Empty; end if; while Present (Assoc) loop Selector_Name := First (Choices (Assoc)); while Present (Selector_Name) loop if Nkind (Selector_Name) /= N_Identifier and then Nkind (Selector_Name) /= N_Others_Choice then Error_Msg_N ("selector name should be identifier or OTHERS", Selector_Name); Bad_Aggregate := True; end if; Selector_Name := Next (Selector_Name); end loop; Assoc := Next (Assoc); end loop; if Bad_Aggregate then return; end if; end Step_2; -- STEP 3: Find discriminant Values Step_3 : declare Discrim : Entity_Id; Missing_Discriminants : Boolean := False; begin if Present (Expressions (N)) then Positional_Expr := First (Expressions (N)); else Positional_Expr := Empty; end if; if Has_Discriminants (Typ) then Discrim := First_Discriminant (Typ); else Discrim := Empty; end if; -- First find the discriminant values in the positional components while Present (Discrim) and then Present (Positional_Expr) loop Next_Expr := Next (Positional_Expr); Remove (Positional_Expr); Add_Association (Discrim, Positional_Expr); Resolve (Positional_Expr, Etype (Discrim)); Check_Non_Static_Context (Positional_Expr); if Present (Get_Value (Discrim, From => Component_Associations (N))) then Error_Msg_NE ("more than one value supplied for discriminant&", N, Discrim); end if; Positional_Expr := Next_Expr; Discrim := Next_Discriminant (Discrim); end loop; -- Find remaining discriminant values, if any, among named components while Present (Discrim) loop Expr := Get_Value (Discrim, From => Component_Associations (N), Consider_Others_Choice => True); if No (Expr) then Error_Msg_NE ("no value supplied for discriminant &", N, Discrim); Missing_Discriminants := True; else Add_Association (Discrim, Expr); Resolve (Expr, Etype (Discrim)); Check_Non_Static_Context (Expr); end if; Discrim := Next_Discriminant (Discrim); end loop; if Missing_Discriminants then return; end if; -- At this point and until the beginning of STEP 6, New_Assoc_List -- contains only the discriminants and their values. end Step_3; -- STEP 4: Set the Etype of the record aggregate if Has_Discriminants (Typ) then Build_Constrained_Itype : declare Discrim_Exprs : Elist_Id := New_Elmt_List; Constr_Itype : Entity_Id := New_Itype (E_Record_Subtype, N); begin New_Assoc := First (New_Assoc_List); while Present (New_Assoc) loop Append_Elmt (Expression (New_Assoc), Discrim_Exprs); New_Assoc := Next (New_Assoc); end loop; Set_Etype (Constr_Itype, Base_Type (Typ)); Set_Esize (Constr_Itype, Esize (Typ)); Set_Is_Tagged_Type (Constr_Itype, Is_Tagged_Type (Typ)); Set_Has_Discriminants (Constr_Itype); Set_Is_Constrained (Constr_Itype); Set_First_Entity (Constr_Itype, First_Entity (Typ)); Set_Last_Entity (Constr_Itype, Last_Entity (Typ)); Set_Discriminant_Constraint (Constr_Itype, Discrim_Exprs); Set_Has_Tasks (Constr_Itype, Has_Tasks (Typ)); Set_Has_Controlled (Constr_Itype, Has_Controlled (Typ)); if Is_Tagged_Type (Typ) then Set_Access_Disp_Table (Constr_Itype, Access_Disp_Table (Typ)); Set_Is_Controlled (Constr_Itype, Is_Controlled (Typ)); end if; Set_Etype (N, Constr_Itype); end Build_Constrained_Itype; else Set_Etype (N, Typ); end if; -- STEP 5: Get remaining components according to discriminant values Step_5 : declare Parent_Typ : Entity_Id; Root_Typ : Entity_Id; Parent_Typ_List : Elist_Id; Parent_Elmt : Elmt_Id; Errors_Found : Boolean := False; begin if Is_Derived_Type (Typ) and then Is_Tagged_Type (Typ) then Parent_Typ_List := New_Elmt_List; -- If this is an extension aggregate, the component list must -- include all components that are not in the given ancestor -- type. Otherwise, the component list must include components -- of all ancestors. if Nkind (N) = N_Extension_Aggregate then Root_Typ := Base_Type (Etype (Ancestor_Part (N))); else Root_Typ := Root_Type (Typ); if Nkind (Parent (Base_Type (Root_Typ))) = N_Private_Type_Declaration then Error_Msg_NE ("type of aggregate has private ancestor&!", N, Root_Typ); Error_Msg_N ("must use extension aggregate!", N); return; end if; Record_Def := Type_Definition (Parent (Base_Type (Root_Typ))); Gather_Components (Component_List (Record_Def), Governed_By => New_Assoc_List, Into => Components, Report_Errors => Errors_Found); end if; Parent_Typ := Base_Type (Typ); while Parent_Typ /= Root_Typ loop Prepend_Elmt (Parent_Typ, To => Parent_Typ_List); Parent_Typ := Etype (Parent_Typ); if Nkind (Parent (Base_Type (Parent_Typ))) = N_Private_Type_Declaration and then Nkind (N) /= N_Extension_Aggregate then Error_Msg_NE ("type of aggregate has private ancestor&!", N, Parent_Typ); Error_Msg_N ("must use extension aggregate!", N); return; end if; end loop; -- Now collect components from all other ancestors. Parent_Elmt := First_Elmt (Parent_Typ_List); while Present (Parent_Elmt) loop Parent_Typ := Node (Parent_Elmt); Record_Def := Type_Definition (Parent (Base_Type (Parent_Typ))); Gather_Components (Component_List (Record_Extension_Part (Record_Def)), Governed_By => New_Assoc_List, Into => Components, Report_Errors => Errors_Found); Parent_Elmt := Next_Elmt (Parent_Elmt); end loop; else Record_Def := Type_Definition (Parent (Base_Type (Typ))); if Null_Present (Record_Def) then null; else Gather_Components (Component_List (Record_Def), Governed_By => New_Assoc_List, Into => Components, Report_Errors => Errors_Found); end if; end if; if Errors_Found then return; end if; end Step_5; -- STEP 6: Find component Values Component_Elmt := First_Elmt (Components); -- First scan the remaining positional associations in the aggregate. -- Remember that at this point Positional_Expr contains the current -- positional association if any is left after looking for discriminant -- values in step 3. while Present (Positional_Expr) and then Present (Component_Elmt) loop Next_Expr := Next (Positional_Expr); Component := Node (Component_Elmt); Remove (Positional_Expr); Add_Association (Component, Positional_Expr); Resolve (Positional_Expr, Replace_Discriminants (In_Type => Etype (Component))); Check_Non_Static_Context (Positional_Expr); if Present (Get_Value (Component, From => Component_Associations (N))) then Error_Msg_NE ("more than one value supplied for Component &", N, Component); end if; Positional_Expr := Next_Expr; Component_Elmt := Next_Elmt (Component_Elmt); end loop; if Present (Positional_Expr) then Error_Msg_N ("too many components for record aggregate", Positional_Expr); end if; -- Now scan for the named arguments of the aggregate while Present (Component_Elmt) loop Component := Node (Component_Elmt); Expr := Get_Value (Component, From => Component_Associations (N), Consider_Others_Choice => True); if No (Expr) then Error_Msg_NE ("no value supplied for component &", N, Component); else Add_Association (Component, Expr); Resolve (Expr, Replace_Discriminants (In_Type => Etype (Component))); Check_Non_Static_Context (Expr); end if; Component_Elmt := Next_Elmt (Component_Elmt); end loop; -- STEP 7: check for invalid components + check type in choice list Step_7 : declare Selectr : Node_Id; -- Selector name Typech : Entity_Id; -- Type of first component in choice list begin if Present (Component_Associations (N)) then Assoc := First (Component_Associations (N)); else Assoc := Empty; end if; Verification : while Present (Assoc) loop Selectr := First (Choices (Assoc)); Typech := Empty; if Nkind (Selectr) = N_Others_Choice then if No (Others_Etype) then Error_Msg_N ("OTHERS must represent at least one component", Selectr); end if; exit Verification; end if; while Present (Selectr) loop New_Assoc := First (New_Assoc_List); while Present (New_Assoc) loop Component := First (Choices (New_Assoc)); exit when Chars (Selectr) = Chars (Component); New_Assoc := Next (New_Assoc); end loop; -- If no association, this is not a a legal component of -- of the type in question, except if this is an internal -- component supplied by a previous expansion. if No (New_Assoc) then if Chars (Selectr) /= Name_uTag and then Chars (Selectr) /= Name_uParent and then Chars (Selectr) /= Name_uController then Error_Msg_N ("component & is undefined", Selectr); end if; elsif No (Typech) then Typech := Base_Type (Etype (Component)); elsif Typech /= Base_Type (Etype (Component)) then Error_Msg_N ("components in choice list must have same type", Selectr); end if; Selectr := Next (Selectr); end loop; Assoc := Next (Assoc); end loop Verification; end Step_7; -- STEP 8: replace the original aggregate Step_8 : declare New_Aggregate : Node_Id := New_Copy (N); begin Set_Expressions (New_Aggregate, No_List); Set_Etype (New_Aggregate, Etype (N)); Set_Component_Associations (New_Aggregate, New_Assoc_List); Rewrite_Substitute_Tree (N, New_Aggregate); end Step_8; end Resolve_Record_Aggregate; ----------------------- -- Gather_Components -- ----------------------- procedure Gather_Components (Comp_List : Node_Id; Governed_By : List_Id; Into : Elist_Id; Report_Errors : out Boolean) is Assoc : Node_Id; Variant : Node_Id; Discrete_Choice : Node_Id; Comp_Item : Node_Id; Discrim : Entity_Id; Discrim_Name : Node_Id; Discrim_Value : Node_Id; begin Report_Errors := False; if No (Comp_List) or else Null_Present (Comp_List) then return; elsif Present (Component_Items (Comp_List)) then Comp_Item := First (Component_Items (Comp_List)); else Comp_Item := Empty; end if; while Present (Comp_Item) loop -- Skip the tag of a tagged record, as well as all items -- that are not user components (anonymous types, rep clauses, -- Parent field, controller field). if Nkind (Comp_Item) = N_Component_Declaration and then Chars (Defining_Identifier (Comp_Item)) /= Name_uTag and then Chars (Defining_Identifier (Comp_Item)) /= Name_uParent and then Chars (Defining_Identifier (Comp_Item)) /= Name_uController then Append_Elmt (Defining_Identifier (Comp_Item), Into); end if; Comp_Item := Next (Comp_Item); end loop; if No (Variant_Part (Comp_List)) then return; else Discrim_Name := Name (Variant_Part (Comp_List)); Variant := First (Variants (Variant_Part (Comp_List))); end if; -- Look for the discriminant that governs this variant part. -- The discriminant *must* be in the Governed_By List Assoc := First (Governed_By); loop Discrim := First (Choices (Assoc)); exit when Chars (Discrim_Name) = Chars (Discrim); Assoc := Next (Assoc); end loop; Discrim_Value := Expression (Assoc); if not (Is_Static_Expression (Discrim_Value) and then Is_Static_Subtype (Etype (Discrim_Value))) then Error_Msg_NE ("value for discriminant & must be static", Discrim_Value, Discrim); Report_Errors := True; return; end if; Search_For_Discriminant_Value : declare Low : Node_Id; High : Node_Id; UI_High : Uint; UI_Low : Uint; UI_Discrim_Value : constant Uint := Expr_Value (Discrim_Value); begin Find_Discrete_Value : while Present (Variant) loop Discrete_Choice := First (Discrete_Choices (Variant)); while Present (Discrete_Choice) loop exit Find_Discrete_Value when Nkind (Discrete_Choice) = N_Others_Choice; Get_Index_Bounds (Discrete_Choice, Low, High); UI_Low := Expr_Value (Low); UI_High := Expr_Value (High); exit Find_Discrete_Value when UI_Low <= UI_Discrim_Value and then UI_High >= UI_Discrim_Value; Discrete_Choice := Next (Discrete_Choice); end loop; Variant := Next (Variant); end loop Find_Discrete_Value; end Search_For_Discriminant_Value; if No (Variant) then Error_Msg_NE ("value of discriminant & is out of range", Discrim_Value, Discrim); Report_Errors := True; return; end if; -- If we have found the corresponding choice, recursively add its -- components to the Into list. Gather_Components (Component_List (Variant), Governed_By, Into, Report_Errors); end Gather_Components; ------------------------ -- Array_Aggr_Subtype -- ------------------------ function Array_Aggr_Subtype (N : Node_Id; Typ : Entity_Id) return Entity_Id is Aggr_Dimension : constant Pos := Number_Dimensions (Typ); -- Number of aggregate index dimensions. Aggr_Range : array (1 .. Aggr_Dimension) of Node_Id := (others => Empty); -- Constrained N_Range of each index dimension in our aggregate itype. Aggr_Low : array (1 .. Aggr_Dimension) of Node_Id := (others => Empty); Aggr_High : array (1 .. Aggr_Dimension) of Node_Id := (others => Empty); -- Low and High bounds for each index dimension in our aggregate itype. procedure Collect_Aggr_Bounds (N : Node_Id; Dim : Pos); -- N is an array (sub-)aggregate. Dim is the dimension corresponding to -- (sub-)aggregate N. This procedure collects the constrained N_Range -- nodes corresponding to each index dimension of our aggregate itype. -- These N_Range nodes are collected in Aggr_Range above. -- Likewise collect in Aggr_Low & Aggr_High above the low and high -- bounds of each index dimension. If, when collecting, two bounds -- corresponding to the same dimension are static and found to differ, -- then emit a warning, and mark N as raising Constraint_Error. ------------------------- -- Collect_Aggr_Bounds -- ------------------------- procedure Collect_Aggr_Bounds (N : Node_Id; Dim : Pos) is This_Range : constant Node_Id := Aggregate_Bounds (N); -- The aggregate range node of this specific sub-aggregate. This_Low : constant Node_Id := Low_Bound (Aggregate_Bounds (N)); This_High : constant Node_Id := High_Bound (Aggregate_Bounds (N)); -- The aggregate bounds of this specific sub-aggregate. Assoc : Node_Id; Expr : Node_Id; begin -- Collect the first N_Range for a given dimension that you find. -- For a given dimension they must be all equal anyway. if No (Aggr_Range (Dim)) then Aggr_Low (Dim) := This_Low; Aggr_High (Dim) := This_High; Aggr_Range (Dim) := This_Range; else if Is_OK_Static_Expression (This_Low) then if not Is_OK_Static_Expression (Aggr_Low (Dim)) then Aggr_Low (Dim) := This_Low; elsif Expr_Value (This_Low) /= Expr_Value (Aggr_Low (Dim)) then Set_Raises_Constraint_Error (N); Error_Msg_N ("Sub-aggregate low bound mismatch?", N); Error_Msg_N ("Constraint_Error will be raised at run-time?", N); end if; end if; if Is_OK_Static_Expression (This_High) then if not Is_OK_Static_Expression (Aggr_High (Dim)) then Aggr_High (Dim) := This_High; elsif Expr_Value (This_High) /= Expr_Value (Aggr_High (Dim)) then Set_Raises_Constraint_Error (N); Error_Msg_N ("Sub-aggregate high bound mismatch?", N); Error_Msg_N ("Constraint_Error will be raised at run-time?", N); end if; end if; end if; if Dim < Aggr_Dimension then -- Process positional components if Present (Expressions (N)) then Expr := First (Expressions (N)); while Present (Expr) loop Collect_Aggr_Bounds (Expr, Dim + 1); Expr := Next (Expr); end loop; end if; -- Process component associations if Present (Component_Associations (N)) then Assoc := First (Component_Associations (N)); while Present (Assoc) loop Expr := Expression (Assoc); Collect_Aggr_Bounds (Expr, Dim + 1); Assoc := Next (Assoc); end loop; end if; end if; end Collect_Aggr_Bounds; -- Array_Aggr_Subtype variables Itype : Entity_Id; -- the final itype of the overall aggregate Index_Constraints : List_Id := New_List; -- The list of index constraints of the aggregate itype. -- Begin of Array_Aggr_Subtype begin Collect_Aggr_Bounds (N, 1); -- Build the list of constrained indices of our aggregate itype. for I in 1 .. Aggr_Dimension loop Create_Index : declare Index_Base : Entity_Id := Base_Type (Etype (Aggr_Range (I))); Index_Typ : Entity_Id; begin -- Construct the Index subtype Index_Typ := New_Itype (Subtype_Kind (Ekind (Index_Base)), N); Set_Etype (Index_Typ, Index_Base); if Is_Character_Type (Index_Base) then Set_Is_Character_Type (Index_Typ, True); end if; Set_Esize (Index_Typ, Esize (Index_Base)); Set_Alignment_Clause (Index_Typ, Alignment_Clause (Index_Base)); Set_Scalar_Range (Index_Typ, Aggr_Range (I)); Set_Etype (Aggr_Range (I), Index_Typ); Append (Aggr_Range (I), To => Index_Constraints); end Create_Index; end loop; -- Now build the Itype Itype := New_Itype (E_Array_Subtype, N); Set_Alignment_Clause (Itype, Alignment_Clause (Typ)); Set_Component_Type (Itype, Component_Type (Typ)); Set_Depends_On_Private (Itype, Has_Private_Component (Typ)); Set_Etype (Itype, Base_Type (Typ)); Set_Esize (Itype, Esize (Typ)); Set_First_Index (Itype, First (Index_Constraints)); Set_Has_Alignment_Clause (Itype, Has_Alignment_Clause (Typ)); Set_Has_Atomic_Components (Itype, Has_Atomic_Components (Typ)); Set_Has_Controlled (Itype, Has_Controlled (Typ)); Set_Has_Non_Standard_Rep (Itype, Has_Non_Standard_Rep (Typ)); Set_Has_Size_Clause (Itype, Has_Size_Clause (Typ)); Set_Is_Aliased (Itype, Is_Aliased (Typ)); Set_Is_Constrained (Itype, True); Set_Is_Internal (Itype, True); Set_Is_Packed (Itype, Is_Packed (Typ)); Set_Suppress_Index_Checks (Itype, Suppress_Index_Checks (Typ)); Set_Suppress_Length_Checks (Itype, Suppress_Length_Checks (Typ)); -- We always need a freeze node for a packed array subtype, so that -- we can build the Packed_Array_Type corresponding to the subtype. if Is_Packed (Itype) then Set_Has_Delayed_Freeze (Itype); end if; -- If the subtype is not that of a record component, build a freeze -- node if parent still needs one. if not Is_Type (Scope (Itype)) then Set_Depends_On_Private (Itype, Depends_On_Private (Typ)); if Has_Delayed_Freeze (Typ) and then not Is_Frozen (Typ) then Set_Has_Delayed_Freeze (Itype); end if; end if; Freeze_Before (Parent (N), Itype); return Itype; end Array_Aggr_Subtype; -------------------- -- Constraint_Err -- -------------------- function Constraint_Err (N : Node_Id) return Boolean is Kind : Node_Kind := Nkind (N); begin return Kind = N_Raise_Constraint_Error or else (Kind in N_Subexpr and then Raises_Constraint_Error (N)); end Constraint_Err; -------------------------------- -- Make_String_Into_Aggregate -- -------------------------------- procedure Make_String_Into_Aggregate (N : Node_Id) is C : Char_Code; C_Node : Node_Id; Exprs : List_Id := New_List; Loc : constant Source_Ptr := Sloc (N); New_N : Node_Id; P : Source_Ptr := Loc + 1; Str : constant String_Id := Strval (N); Strlen : constant Nat := String_Length (Str); begin for J in 1 .. Strlen loop C := Get_String_Char (Str, J); Set_Character_Literal_Name (C); C_Node := Make_Character_Literal (P, Name_Find, C); Set_Etype (C_Node, Any_Character); Set_Analyzed (C_Node); Append_To (Exprs, C_Node); P := P + 1; -- something special for wide strings ? end loop; New_N := Make_Aggregate (Loc, Expressions => Exprs); Set_Analyzed (New_N); Set_Etype (New_N, Any_Composite); Rewrite_Substitute_Tree (N, New_N); end Make_String_Into_Aggregate; --------------- -- Raises_CE -- --------------- function Raises_CE (N : Node_Id; Dim : Pos) return Boolean is Assoc : Node_Id; Expr : Node_Id; begin if Constraint_Err (N) then return True; end if; if Dim > 1 then -- Process component associations if Present (Component_Associations (N)) then Assoc := First (Component_Associations (N)); while Present (Assoc) loop Expr := Expression (Assoc); if Raises_CE (Expr, Dim - 1) then return True; end if; Assoc := Next (Assoc); end loop; end if; -- Process positional components if Present (Expressions (N)) then Expr := First (Expressions (N)); while Present (Expr) loop if Raises_CE (Expr, Dim - 1) then return True; end if; Expr := Next (Expr); end loop; end if; end if; return False; end Raises_CE; ----------------------------- -- Resolve_Array_Aggregate -- ----------------------------- function Resolve_Array_Aggregate (N : Node_Id; Index : Node_Id; Component_Typ : Entity_Id; Others_Allowed : Boolean) return Boolean is Loc : constant Source_Ptr := Sloc (N); Failure : constant Boolean := False; Success : constant Boolean := True; Index_Typ : constant Entity_Id := Etype (Index); Index_Typ_Low : constant Node_Id := Type_Low_Bound (Index_Typ); Index_Typ_High : constant Node_Id := Type_High_Bound (Index_Typ); -- The type of the index corresponding to the array sub-aggregate -- along with its low and upper bounds Index_Base : constant Entity_Id := Base_Type (Index_Typ); Index_Base_Low : constant Node_Id := Type_Low_Bound (Index_Base); Index_Base_High : constant Node_Id := Type_High_Bound (Index_Base); -- ditto for the base type function Add (Val : Uint; To : Node_Id) return Node_Id; -- Creates a new expression node where Val is added to expression To. -- Tries to constant fold whenever possible. To must be an already -- analyzed expression. procedure Check_Bounds (L, H : Node_Id; AL, AH : Node_Id); -- Checks that range AL .. AH is compatible with range L .. H. Emits a -- warning if not and sets the Raises_Constraint_Error Flag in N. procedure Check_Length (L, H : Node_Id; Len : Uint); -- Checks that range L .. H contains at least Len elements. Emits a -- warning if not and sets the Raises_Constraint_Error Flag in N. function Dynamic_Or_Null_Range (L, H : Node_Id) return Boolean; -- Returns True if range L .. H is dynamic or null. procedure Get (Value : out Uint; From : Node_Id; OK : out Boolean); -- Given expression node From, this routine sets OK to False if it -- cannot statically evaluate From. Otherwise it stores this static -- value into Value. function Index_Typ_First return Node_Id; -- Returns Index_Typ'First. function Resolve_Aggr_Expr (Expr : Node_Id) return Boolean; -- Resolves aggregate expression Expr. Returs False if resolution fails. --------- -- Add -- --------- function Add (Val : Uint; To : Node_Id) return Node_Id is Expr_Pos : Node_Id; Expr : Node_Id; To_Pos : Node_Id; begin if Constraint_Err (To) then return To; end if; -- First test if we can do constant folding if Is_OK_Static_Expression (To) then Expr_Pos := Make_Integer_Literal (Loc, Expr_Value (To) + Val); Set_Is_Static_Expression (Expr_Pos); if not Is_Enumeration_Type (Index_Typ) then Expr := Expr_Pos; -- If we are dealing with enumeration return -- Index_Typ'Val (Expr_Pos) else Expr := Make_Attribute_Reference (Loc, Prefix => New_Reference_To (Index_Typ, Loc), Attribute_Name => Name_Val, Expressions => New_List (Expr_Pos)); end if; return Expr; end if; -- If we are here no constant folding possible if not Is_Enumeration_Type (Index_Base) then Expr := Make_Op_Add (Loc, Left_Opnd => Duplicate_Subexpr (To), Right_Opnd => Make_Integer_Literal (Loc, Val)); -- If we are dealing with enumeration return -- Index_Typ'Val (Index_Typ'Pos (To) + Val) else To_Pos := Make_Attribute_Reference (Loc, Prefix => New_Reference_To (Index_Typ, Loc), Attribute_Name => Name_Pos, Expressions => New_List (Duplicate_Subexpr (To))); Expr_Pos := Make_Op_Add (Loc, Left_Opnd => To_Pos, Right_Opnd => Make_Integer_Literal (Loc, Val)); Expr := Make_Attribute_Reference (Loc, Prefix => New_Reference_To (Index_Typ, Loc), Attribute_Name => Name_Val, Expressions => New_List (Expr_Pos)); end if; return Expr; end Add; ------------------ -- Check_Bounds -- ------------------ procedure Check_Bounds (L, H : Node_Id; AL, AH : Node_Id) is Val_L : Uint; Val_H : Uint; Val_AL : Uint; Val_AH : Uint; OK_L : Boolean; OK_H : Boolean; OK_AL : Boolean; OK_AH : Boolean; begin if Constraint_Err (N) or else Dynamic_Or_Null_Range (AL, AH) then return; end if; Get (Value => Val_L, From => L, OK => OK_L); Get (Value => Val_H, From => H, OK => OK_H); Get (Value => Val_AL, From => AL, OK => OK_AL); Get (Value => Val_AH, From => AH, OK => OK_AH); if OK_L and then Val_L > Val_AL then Set_Raises_Constraint_Error (N); Error_Msg_N ("lower bound out of range?", AL); Error_Msg_N ("Constraint_Error will be raised at run-time?", AL); end if; if OK_H and then Val_H < Val_AH then Set_Raises_Constraint_Error (N); Error_Msg_N ("upper bound out of range?", AH); Error_Msg_N ("Constraint_Error will be raised at run-time?", AH); end if; end Check_Bounds; ------------------ -- Check_Length -- ------------------ procedure Check_Length (L, H : Node_Id; Len : Uint) is Val_L : Uint; Val_H : Uint; OK_L : Boolean; OK_H : Boolean; Range_Len : Uint; begin if Constraint_Err (N) then return; end if; Get (Value => Val_L, From => L, OK => OK_L); Get (Value => Val_H, From => H, OK => OK_H); if not OK_L or else not OK_H then return; end if; -- If null range length is zero if Val_L > Val_H then Range_Len := Uint_0; else Range_Len := Val_H - Val_L + 1; end if; if Range_Len < Len then Set_Raises_Constraint_Error (N); Error_Msg_N ("Too many elements?", N); Error_Msg_N ("Constraint_Error will be raised at run-time?", N); end if; end Check_Length; --------------------------- -- Dynamic_Or_Null_Range -- --------------------------- function Dynamic_Or_Null_Range (L, H : Node_Id) return Boolean is begin return not Is_OK_Static_Expression (L) or else not Is_OK_Static_Expression (H) or else Expr_Value (L) > Expr_Value (H); end Dynamic_Or_Null_Range; --------- -- Get -- --------- procedure Get (Value : out Uint; From : Node_Id; OK : out Boolean) is begin OK := True; if Is_OK_Static_Expression (From) then Value := Expr_Value (From); -- If expression From is something like Some_Type'Val (10) then -- Value = 10 elsif Nkind (From) = N_Attribute_Reference and then Attribute_Name (From) = Name_Val and then Is_OK_Static_Expression (First (Expressions (From))) then Value := Expr_Value (First (Expressions (From))); else OK := False; end if; end Get; --------------------- -- Index_Typ_First -- --------------------- function Index_Typ_First return Node_Id is begin return Make_Attribute_Reference (Loc, Prefix => New_Reference_To (Index_Typ, Loc), Attribute_Name => Name_First); end Index_Typ_First; ----------------------- -- Resolve_Aggr_Expr -- ----------------------- function Resolve_Aggr_Expr (Expr : Node_Id) return Boolean is Nxt_Index : Node_Id := Next_Index (Index); -- Index is the current index corresponding to the expresion. begin if Present (Nxt_Index) then if Nkind (Expr) /= N_Aggregate then -- A string literal can appear where a one-dimensional array -- of characters is expected. if Is_Character_Type (Component_Typ) and then No (Next_Index (Nxt_Index)) and then Nkind (Expr) = N_String_Literal then Make_String_Into_Aggregate (Expr); else Error_Msg_N ("nested array aggregate expected", Expr); return Failure; end if; end if; return Resolve_Array_Aggregate (Expr, Nxt_Index, Component_Typ, Others_Allowed); else Resolve (Expr, Component_Typ); Check_Non_Static_Context (Expr); end if; return Success; end Resolve_Aggr_Expr; -- Variables local to Resolve_Array_Aggregate Assoc : Node_Id; Choice : Node_Id; Expr : Node_Id; Who_Cares : Node_Id; Aggr_Low : Node_Id := Empty; Aggr_High : Node_Id := Empty; -- The actual low and high bounds of this sub-aggegate Choices_Low : Node_Id := Empty; Choices_High : Node_Id := Empty; -- The lowest and highest discrete choices values for a named aggregate Nb_Elements : Uint := Uint_0; -- The number of elements in a positional aggegate Others_Present : Boolean := False; Nb_Choices : Nat := 0; -- Contains the overall number of named choices in this sub-aggregate Nb_Discrete_Choices : Nat := 0; -- The overall number of discrete choices (not counting others choice) Case_Table_Size : Nat; -- Contains the size of the case table needed to sort aggregate choices -- Begin of Resolve_Array_Aggregate begin -- STEP 1: make sure the aggregate is correctly formatted if Etype (N) = Any_Type then Set_Etype (N, Any_Composite); return Failure; end if; -- At this point we know that the others choice, if present, is by -- itself and appears last in the aggregate. if Present (Expressions (N)) and then Present (Component_Associations (N)) and then Nkind (First (Choices (First (Component_Associations (N))))) /= N_Others_Choice then Error_Msg_N ("mixed positional/named associations", N); return Failure; end if; -- Test for the validity of an others choice if present if Present (Component_Associations (N)) then Assoc := Last (Component_Associations (N)); Others_Present := (Nkind (First (Choices (Assoc))) = N_Others_Choice); else Others_Present := False; end if; if Others_Present and then (not Others_Allowed) then Error_Msg_N ("OTHERS choice not allowed here", First (Choices (Assoc))); return Failure; end if; -- STEP 2: Process named components if No (Expressions (N)) then -- Count the overall number of choices so that we can allocate array -- Table below to contain the discrete choices in the aggregate. Assoc := First (Component_Associations (N)); while Present (Assoc) loop Choice := First (Choices (Assoc)); while Present (Choice) loop Nb_Choices := Nb_Choices + 1; Choice := Next (Choice); end loop; Assoc := Next (Assoc); end loop; if Others_Present then Case_Table_Size := Nb_Choices - 1; else Case_Table_Size := Nb_Choices; end if; Step_2 : declare Low : Node_Id; High : Node_Id; -- Denote the lowest and highest values in an aggregate choice S_Low : Node_Id := Empty; S_High : Node_Id := Empty; -- if a choice in an aggregate is a subtype indication these -- denote the lowest and highest values of the subtype Table : Case_Table_Type (1 .. Case_Table_Size); -- Used to sort all the different choice values begin -- STEP 2 (A): Check discrete choices validity. Assoc := First (Component_Associations (N)); while Present (Assoc) loop Choice := First (Choices (Assoc)); while Present (Choice) loop Analyze (Choice); if Nkind (Choice) = N_Others_Choice then exit; -- Test for subtype mark without constraint elsif Is_Entity_Name (Choice) and then Is_Type (Entity (Choice)) then if Base_Type (Entity (Choice)) /= Index_Base then Error_Msg_N ("invalid subtype mark in aggregate choice", Choice); return Failure; end if; elsif Nkind (Choice) = N_Subtype_Indication then Resolve_Discrete_Subtype_Indication (Choice, Index_Typ); -- Does the subtype indication evaluation raise CE ? Get_Index_Bounds (Subtype_Mark (Choice), S_Low, S_High); Get_Index_Bounds (Choice, Low, High); Check_Bounds (S_Low, S_High, Low, High); else -- Choice is a range or an expression Resolve (Choice, Index_Typ); Check_Non_Static_Context (Choice); end if; -- If we could not resolve the discrete choice stop here if Etype (Choice) = Any_Type then return Failure; end if; Get_Index_Bounds (Choice, Low, High); if (Dynamic_Or_Null_Range (Low, High) or else (Nkind (Choice) = N_Subtype_Indication and then Dynamic_Or_Null_Range (S_Low, S_High))) and then Nb_Choices /= 1 then Error_Msg_N ("dynamic or empty choice in aggregate " & "must be the only choice", Choice); return Failure; end if; Nb_Discrete_Choices := Nb_Discrete_Choices + 1; Table (Nb_Discrete_Choices).Choice_Lo := Low; Table (Nb_Discrete_Choices).Choice_Hi := High; Choice := Next (Choice); end loop; if not Resolve_Aggr_Expr (Expression (Assoc)) then return Failure; end if; Assoc := Next (Assoc); end loop; -- If aggregate contains more than one choice then these must be -- static. Sort them and check that they are contiguous if Nb_Discrete_Choices > 1 then Sort_Case_Table (Table); for J in 1 .. Nb_Discrete_Choices - 1 loop if Expr_Value (Table (J).Choice_Hi) >= Expr_Value (Table (J + 1).Choice_Lo) then Error_Msg_N ("duplicate choice values in array aggregate", Table (J).Choice_Hi); return Failure; elsif (not Others_Present) and then (Expr_Value (Table (J + 1).Choice_Lo) - Expr_Value (Table (J).Choice_Hi)) > 1 then Error_Msg_N ("missing association in array aggregate", N); Set_Etype (N, Any_Composite); return Failure; end if; end loop; end if; -- STEP 2 (B): Compute aggregate bounds and min/max choices values if Nb_Discrete_Choices > 0 then Choices_Low := Table (1).Choice_Lo; Choices_High := Table (Nb_Discrete_Choices).Choice_Hi; end if; if Others_Present then Get_Index_Bounds (Index, Aggr_Low, Aggr_High); else Aggr_Low := Choices_Low; Aggr_High := Choices_High; end if; end Step_2; -- STEP 3: Process positional components else -- STEP 3 (A): Process positional elements Expr := First (Expressions (N)); Nb_Elements := Uint_0; while Present (Expr) loop Nb_Elements := Nb_Elements + 1; if not Resolve_Aggr_Expr (Expr) then return Failure; end if; Expr := Next (Expr); end loop; if Others_Present then Assoc := Last (Component_Associations (N)); if not Resolve_Aggr_Expr (Expression (Assoc)) then return Failure; end if; end if; -- STEP 3 (B): Compute the aggregate bounds if Others_Present then Get_Index_Bounds (Index, Aggr_Low, Aggr_High); else if Others_Allowed then Get_Index_Bounds (Index, Aggr_Low, Who_Cares); else Aggr_Low := Index_Typ_Low; end if; Aggr_High := Add (Nb_Elements - 1, To => Aggr_Low); end if; end if; -- STEP 4: Perform static aggregate checks and save the bounds -- Check (A) Check_Bounds (Index_Typ_Low, Index_Typ_High, Aggr_Low, Aggr_High); Check_Bounds (Index_Base_Low, Index_Base_High, Aggr_Low, Aggr_High); -- Check (B) if Others_Present and then Nb_Discrete_Choices > 0 then Check_Bounds (Index_Typ_Low, Index_Typ_High, Choices_Low, Choices_High); Check_Bounds (Index_Base_Low, Index_Base_High, Choices_Low, Choices_High); -- Check (C) elsif Others_Present and then Nb_Elements > 0 then Check_Length (Index_Typ_Low, Index_Typ_High, Nb_Elements); Check_Length (Index_Base_Low, Index_Base_High, Nb_Elements); end if; if Constraint_Err (Aggr_Low) or else Constraint_Err (Aggr_High) then Set_Raises_Constraint_Error (N); end if; Aggr_Low := Duplicate_Subexpr (Aggr_Low); -- Do not duplicate Aggr_High if Aggr_High = Aggr_Low + Nb_Elements -- since the addition node returned by Add is not yet analyzed if Others_Present or else Nb_Discrete_Choices > 0 then Aggr_High := Duplicate_Subexpr (Aggr_High); end if; Set_Aggregate_Bounds (N, Make_Range (Loc, Low_Bound => Aggr_Low, High_Bound => Aggr_High)); Analyze (Aggregate_Bounds (N)); Resolve (Aggregate_Bounds (N), Index_Typ); return Success; end Resolve_Array_Aggregate; end Sem_Aggr;