------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- C H E C K S -- -- -- -- B o d y -- -- -- -- -- -- Copyright (C) 1992-2002 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 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, 59 Temple Place - Suite 330, Boston, -- -- MA 02111-1307, USA. -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ with Atree; use Atree; with Debug; use Debug; with Einfo; use Einfo; with Errout; use Errout; with Exp_Ch2; use Exp_Ch2; with Exp_Util; use Exp_Util; with Elists; use Elists; with Freeze; use Freeze; with Nlists; use Nlists; with Nmake; use Nmake; with Opt; use Opt; with Restrict; use Restrict; with Rtsfind; use Rtsfind; with Sem; use Sem; with Sem_Eval; use Sem_Eval; with Sem_Res; use Sem_Res; with Sem_Util; use Sem_Util; with Sem_Warn; use Sem_Warn; with Sinfo; use Sinfo; with Snames; use Snames; with Stand; use Stand; with Targparm; use Targparm; with Tbuild; use Tbuild; with Ttypes; use Ttypes; with Urealp; use Urealp; with Validsw; use Validsw; package body Checks is -- General note: many of these routines are concerned with generating -- checking code to make sure that constraint error is raised at runtime. -- Clearly this code is only needed if the expander is active, since -- otherwise we will not be generating code or going into the runtime -- execution anyway. -- We therefore disconnect most of these checks if the expander is -- inactive. This has the additional benefit that we do not need to -- worry about the tree being messed up by previous errors (since errors -- turn off expansion anyway). -- There are a few exceptions to the above rule. For instance routines -- such as Apply_Scalar_Range_Check that do not insert any code can be -- safely called even when the Expander is inactive (but Errors_Detected -- is 0). The benefit of executing this code when expansion is off, is -- the ability to emit constraint error warning for static expressions -- even when we are not generating code. ---------------------------- -- Local Subprogram Specs -- ---------------------------- procedure Apply_Selected_Length_Checks (Ck_Node : Node_Id; Target_Typ : Entity_Id; Source_Typ : Entity_Id; Do_Static : Boolean); -- This is the subprogram that does all the work for Apply_Length_Check -- and Apply_Static_Length_Check. Expr, Target_Typ and Source_Typ are as -- described for the above routines. The Do_Static flag indicates that -- only a static check is to be done. procedure Apply_Selected_Range_Checks (Ck_Node : Node_Id; Target_Typ : Entity_Id; Source_Typ : Entity_Id; Do_Static : Boolean); -- This is the subprogram that does all the work for Apply_Range_Check. -- Expr, Target_Typ and Source_Typ are as described for the above -- routine. The Do_Static flag indicates that only a static check is -- to be done. function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id; -- If a discriminal is used in constraining a prival, Return reference -- to the discriminal of the protected body (which renames the parameter -- of the enclosing protected operation). This clumsy transformation is -- needed because privals are created too late and their actual subtypes -- are not available when analysing the bodies of the protected operations. -- To be cleaned up??? function Guard_Access (Cond : Node_Id; Loc : Source_Ptr; Ck_Node : Node_Id) return Node_Id; -- In the access type case, guard the test with a test to ensure -- that the access value is non-null, since the checks do not -- not apply to null access values. procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr); -- Called by Apply_{Length,Range}_Checks to rewrite the tree with the -- Constraint_Error node. function Selected_Length_Checks (Ck_Node : Node_Id; Target_Typ : Entity_Id; Source_Typ : Entity_Id; Warn_Node : Node_Id) return Check_Result; -- Like Apply_Selected_Length_Checks, except it doesn't modify -- anything, just returns a list of nodes as described in the spec of -- this package for the Range_Check function. function Selected_Range_Checks (Ck_Node : Node_Id; Target_Typ : Entity_Id; Source_Typ : Entity_Id; Warn_Node : Node_Id) return Check_Result; -- Like Apply_Selected_Range_Checks, except it doesn't modify anything, -- just returns a list of nodes as described in the spec of this package -- for the Range_Check function. ------------------------------ -- Access_Checks_Suppressed -- ------------------------------ function Access_Checks_Suppressed (E : Entity_Id) return Boolean is begin return Scope_Suppress.Access_Checks or else (Present (E) and then Suppress_Access_Checks (E)); end Access_Checks_Suppressed; ------------------------------------- -- Accessibility_Checks_Suppressed -- ------------------------------------- function Accessibility_Checks_Suppressed (E : Entity_Id) return Boolean is begin return Scope_Suppress.Accessibility_Checks or else (Present (E) and then Suppress_Accessibility_Checks (E)); end Accessibility_Checks_Suppressed; ------------------------- -- Append_Range_Checks -- ------------------------- procedure Append_Range_Checks (Checks : Check_Result; Stmts : List_Id; Suppress_Typ : Entity_Id; Static_Sloc : Source_Ptr; Flag_Node : Node_Id) is Internal_Flag_Node : Node_Id := Flag_Node; Internal_Static_Sloc : Source_Ptr := Static_Sloc; Checks_On : constant Boolean := (not Index_Checks_Suppressed (Suppress_Typ)) or else (not Range_Checks_Suppressed (Suppress_Typ)); begin -- For now we just return if Checks_On is false, however this should -- be enhanced to check for an always True value in the condition -- and to generate a compilation warning??? if not Checks_On then return; end if; for J in 1 .. 2 loop exit when No (Checks (J)); if Nkind (Checks (J)) = N_Raise_Constraint_Error and then Present (Condition (Checks (J))) then if not Has_Dynamic_Range_Check (Internal_Flag_Node) then Append_To (Stmts, Checks (J)); Set_Has_Dynamic_Range_Check (Internal_Flag_Node); end if; else Append_To (Stmts, Make_Raise_Constraint_Error (Internal_Static_Sloc, Reason => CE_Range_Check_Failed)); end if; end loop; end Append_Range_Checks; ------------------------ -- Apply_Access_Check -- ------------------------ procedure Apply_Access_Check (N : Node_Id) is P : constant Node_Id := Prefix (N); begin if Inside_A_Generic then return; end if; if Is_Entity_Name (P) then Check_Unset_Reference (P); end if; if Is_Entity_Name (P) and then Access_Checks_Suppressed (Entity (P)) then return; elsif Access_Checks_Suppressed (Etype (P)) then return; else Set_Do_Access_Check (N, True); end if; end Apply_Access_Check; ------------------------------- -- Apply_Accessibility_Check -- ------------------------------- procedure Apply_Accessibility_Check (N : Node_Id; Typ : Entity_Id) is Loc : constant Source_Ptr := Sloc (N); Param_Ent : constant Entity_Id := Param_Entity (N); Param_Level : Node_Id; Type_Level : Node_Id; begin if Inside_A_Generic then return; -- Only apply the run-time check if the access parameter -- has an associated extra access level parameter and -- when the level of the type is less deep than the level -- of the access parameter. elsif Present (Param_Ent) and then Present (Extra_Accessibility (Param_Ent)) and then UI_Gt (Object_Access_Level (N), Type_Access_Level (Typ)) and then not Accessibility_Checks_Suppressed (Param_Ent) and then not Accessibility_Checks_Suppressed (Typ) then Param_Level := New_Occurrence_Of (Extra_Accessibility (Param_Ent), Loc); Type_Level := Make_Integer_Literal (Loc, Type_Access_Level (Typ)); -- Raise Program_Error if the accessibility level of the -- the access parameter is deeper than the level of the -- target access type. Insert_Action (N, Make_Raise_Program_Error (Loc, Condition => Make_Op_Gt (Loc, Left_Opnd => Param_Level, Right_Opnd => Type_Level), Reason => PE_Accessibility_Check_Failed)); Analyze_And_Resolve (N); end if; end Apply_Accessibility_Check; --------------------------- -- Apply_Alignment_Check -- --------------------------- procedure Apply_Alignment_Check (E : Entity_Id; N : Node_Id) is AC : constant Node_Id := Address_Clause (E); Expr : Node_Id; Loc : Source_Ptr; begin if No (AC) or else Range_Checks_Suppressed (E) then return; end if; Loc := Sloc (AC); Expr := Expression (AC); if Nkind (Expr) = N_Unchecked_Type_Conversion then Expr := Expression (Expr); elsif Nkind (Expr) = N_Function_Call and then Is_RTE (Entity (Name (Expr)), RE_To_Address) then Expr := First (Parameter_Associations (Expr)); if Nkind (Expr) = N_Parameter_Association then Expr := Explicit_Actual_Parameter (Expr); end if; end if; -- Here Expr is the address value. See if we know that the -- value is unacceptable at compile time. if Compile_Time_Known_Value (Expr) and then Known_Alignment (E) then if Expr_Value (Expr) mod Alignment (E) /= 0 then Insert_Action (N, Make_Raise_Program_Error (Loc, Reason => PE_Misaligned_Address_Value)); Error_Msg_NE ("?specified address for& not " & "consistent with alignment", Expr, E); end if; -- Here we do not know if the value is acceptable, generate -- code to raise PE if alignment is inappropriate. else -- Skip generation of this code if we don't want elab code if not Restrictions (No_Elaboration_Code) then Insert_After_And_Analyze (N, Make_Raise_Program_Error (Loc, Condition => Make_Op_Ne (Loc, Left_Opnd => Make_Op_Mod (Loc, Left_Opnd => Unchecked_Convert_To (RTE (RE_Integer_Address), Duplicate_Subexpr (Expr)), Right_Opnd => Make_Attribute_Reference (Loc, Prefix => New_Occurrence_Of (E, Loc), Attribute_Name => Name_Alignment)), Right_Opnd => Make_Integer_Literal (Loc, Uint_0)), Reason => PE_Misaligned_Address_Value), Suppress => All_Checks); end if; end if; return; end Apply_Alignment_Check; ------------------------------------- -- Apply_Arithmetic_Overflow_Check -- ------------------------------------- -- This routine is called only if the type is an integer type, and -- a software arithmetic overflow check must be performed for op -- (add, subtract, multiply). The check is performed only if -- Software_Overflow_Checking is enabled and Do_Overflow_Check -- is set. In this case we expand the operation into a more complex -- sequence of tests that ensures that overflow is properly caught. procedure Apply_Arithmetic_Overflow_Check (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Typ : constant Entity_Id := Etype (N); Rtyp : constant Entity_Id := Root_Type (Typ); Siz : constant Int := UI_To_Int (Esize (Rtyp)); Dsiz : constant Int := Siz * 2; Opnod : Node_Id; Ctyp : Entity_Id; Opnd : Node_Id; Cent : RE_Id; Lo : Uint; Hi : Uint; OK : Boolean; begin if Backend_Overflow_Checks_On_Target or not Do_Overflow_Check (N) or not Expander_Active then return; end if; -- Nothing to do if the range of the result is known OK Determine_Range (N, OK, Lo, Hi); -- Note in the test below that we assume that if a bound of the -- range is equal to that of the type. That's not quite accurate -- but we do this for the following reasons: -- a) The way that Determine_Range works, it will typically report -- the bounds of the value are the bounds of the type, because -- it either can't tell anything more precise, or does not think -- it is worth the effort to be more precise. -- b) It is very unusual to have a situation in which this would -- generate an unnecessary overflow check (an example would be -- a subtype with a range 0 .. Integer'Last - 1 to which the -- literal value one is added. -- c) The alternative is a lot of special casing in this routine -- which would partially duplicate the Determine_Range processing. if OK and then Lo > Expr_Value (Type_Low_Bound (Typ)) and then Hi < Expr_Value (Type_High_Bound (Typ)) then return; end if; -- None of the special case optimizations worked, so there is nothing -- for it but to generate the full general case code: -- x op y -- is expanded into -- Typ (Checktyp (x) op Checktyp (y)); -- where Typ is the type of the original expression, and Checktyp is -- an integer type of sufficient length to hold the largest possible -- result. -- In the case where check type exceeds the size of Long_Long_Integer, -- we use a different approach, expanding to: -- typ (xxx_With_Ovflo_Check (Integer_64 (x), Integer (y))) -- where xxx is Add, Multiply or Subtract as appropriate -- Find check type if one exists if Dsiz <= Standard_Integer_Size then Ctyp := Standard_Integer; elsif Dsiz <= Standard_Long_Long_Integer_Size then Ctyp := Standard_Long_Long_Integer; -- No check type exists, use runtime call else if Nkind (N) = N_Op_Add then Cent := RE_Add_With_Ovflo_Check; elsif Nkind (N) = N_Op_Multiply then Cent := RE_Multiply_With_Ovflo_Check; else pragma Assert (Nkind (N) = N_Op_Subtract); Cent := RE_Subtract_With_Ovflo_Check; end if; Rewrite (N, OK_Convert_To (Typ, Make_Function_Call (Loc, Name => New_Reference_To (RTE (Cent), Loc), Parameter_Associations => New_List ( OK_Convert_To (RTE (RE_Integer_64), Left_Opnd (N)), OK_Convert_To (RTE (RE_Integer_64), Right_Opnd (N)))))); Analyze_And_Resolve (N, Typ); return; end if; -- If we fall through, we have the case where we do the arithmetic in -- the next higher type and get the check by conversion. In these cases -- Ctyp is set to the type to be used as the check type. Opnod := Relocate_Node (N); Opnd := OK_Convert_To (Ctyp, Left_Opnd (Opnod)); Analyze (Opnd); Set_Etype (Opnd, Ctyp); Set_Analyzed (Opnd, True); Set_Left_Opnd (Opnod, Opnd); Opnd := OK_Convert_To (Ctyp, Right_Opnd (Opnod)); Analyze (Opnd); Set_Etype (Opnd, Ctyp); Set_Analyzed (Opnd, True); Set_Right_Opnd (Opnod, Opnd); -- The type of the operation changes to the base type of the check -- type, and we reset the overflow check indication, since clearly -- no overflow is possible now that we are using a double length -- type. We also set the Analyzed flag to avoid a recursive attempt -- to expand the node. Set_Etype (Opnod, Base_Type (Ctyp)); Set_Do_Overflow_Check (Opnod, False); Set_Analyzed (Opnod, True); -- Now build the outer conversion Opnd := OK_Convert_To (Typ, Opnod); Analyze (Opnd); Set_Etype (Opnd, Typ); Set_Analyzed (Opnd, True); Set_Do_Overflow_Check (Opnd, True); Rewrite (N, Opnd); end Apply_Arithmetic_Overflow_Check; ---------------------------- -- Apply_Array_Size_Check -- ---------------------------- -- Note: Really of course this entre check should be in the backend, -- and perhaps this is not quite the right value, but it is good -- enough to catch the normal cases (and the relevant ACVC tests!) procedure Apply_Array_Size_Check (N : Node_Id; Typ : Entity_Id) is Loc : constant Source_Ptr := Sloc (N); Ctyp : constant Entity_Id := Component_Type (Typ); Ent : constant Entity_Id := Defining_Identifier (N); Decl : Node_Id; Lo : Node_Id; Hi : Node_Id; Lob : Uint; Hib : Uint; Siz : Uint; Xtyp : Entity_Id; Indx : Node_Id; Sizx : Node_Id; Code : Node_Id; Static : Boolean := True; -- Set false if any index subtye bound is non-static Umark : constant Uintp.Save_Mark := Uintp.Mark; -- We can throw away all the Uint computations here, since they are -- done only to generate boolean test results. Check_Siz : Uint; -- Size to check against function Is_Address_Or_Import (Decl : Node_Id) return Boolean; -- Determines if Decl is an address clause or Import/Interface pragma -- that references the defining identifier of the current declaration. -------------------------- -- Is_Address_Or_Import -- -------------------------- function Is_Address_Or_Import (Decl : Node_Id) return Boolean is begin if Nkind (Decl) = N_At_Clause then return Chars (Identifier (Decl)) = Chars (Ent); elsif Nkind (Decl) = N_Attribute_Definition_Clause then return Chars (Decl) = Name_Address and then Nkind (Name (Decl)) = N_Identifier and then Chars (Name (Decl)) = Chars (Ent); elsif Nkind (Decl) = N_Pragma then if (Chars (Decl) = Name_Import or else Chars (Decl) = Name_Interface) and then Present (Pragma_Argument_Associations (Decl)) then declare F : constant Node_Id := First (Pragma_Argument_Associations (Decl)); begin return Present (F) and then Present (Next (F)) and then Nkind (Expression (Next (F))) = N_Identifier and then Chars (Expression (Next (F))) = Chars (Ent); end; else return False; end if; else return False; end if; end Is_Address_Or_Import; -- Start of processing for Apply_Array_Size_Check begin if not Expander_Active or else Storage_Checks_Suppressed (Typ) then return; end if; -- It is pointless to insert this check inside an _init_proc, because -- that's too late, we have already built the object to be the right -- size, and if it's too large, too bad! if Inside_Init_Proc then return; end if; -- Look head for pragma interface/import or address clause applying -- to this entity. If found, we suppress the check entirely. For now -- we only look ahead 20 declarations to stop this becoming too slow -- Note that eventually this whole routine gets moved to gigi. Decl := N; for Ctr in 1 .. 20 loop Next (Decl); exit when No (Decl); if Is_Address_Or_Import (Decl) then return; end if; end loop; -- First step is to calculate the maximum number of elements. For this -- calculation, we use the actual size of the subtype if it is static, -- and if a bound of a subtype is non-static, we go to the bound of the -- base type. Siz := Uint_1; Indx := First_Index (Typ); while Present (Indx) loop Xtyp := Etype (Indx); Lo := Type_Low_Bound (Xtyp); Hi := Type_High_Bound (Xtyp); -- If any bound raises constraint error, we will never get this -- far, so there is no need to generate any kind of check. if Raises_Constraint_Error (Lo) or else Raises_Constraint_Error (Hi) then Uintp.Release (Umark); return; end if; -- Otherwise get bounds values if Is_Static_Expression (Lo) then Lob := Expr_Value (Lo); else Lob := Expr_Value (Type_Low_Bound (Base_Type (Xtyp))); Static := False; end if; if Is_Static_Expression (Hi) then Hib := Expr_Value (Hi); else Hib := Expr_Value (Type_High_Bound (Base_Type (Xtyp))); Static := False; end if; Siz := Siz * UI_Max (Hib - Lob + 1, Uint_0); Next_Index (Indx); end loop; -- Compute the limit against which we want to check. For subprograms, -- where the array will go on the stack, we use 8*2**24, which (in -- bits) is the size of a 16 megabyte array. if Is_Subprogram (Scope (Ent)) then Check_Siz := Uint_2 ** 27; else Check_Siz := Uint_2 ** 31; end if; -- If we have all static bounds and Siz is too large, then we know we -- know we have a storage error right now, so generate message if Static and then Siz >= Check_Siz then Insert_Action (N, Make_Raise_Storage_Error (Loc, Reason => SE_Object_Too_Large)); Warn_On_Instance := True; Error_Msg_N ("?Storage_Error will be raised at run-time", N); Warn_On_Instance := False; Uintp.Release (Umark); return; end if; -- Case of component size known at compile time. If the array -- size is definitely in range, then we do not need a check. if Known_Esize (Ctyp) and then Siz * Esize (Ctyp) < Check_Siz then Uintp.Release (Umark); return; end if; -- Here if a dynamic check is required -- What we do is to build an expression for the size of the array, -- which is computed as the 'Size of the array component, times -- the size of each dimension. Uintp.Release (Umark); Sizx := Make_Attribute_Reference (Loc, Prefix => New_Occurrence_Of (Ctyp, Loc), Attribute_Name => Name_Size); Indx := First_Index (Typ); for J in 1 .. Number_Dimensions (Typ) loop if Sloc (Etype (Indx)) = Sloc (N) then Ensure_Defined (Etype (Indx), N); end if; Sizx := Make_Op_Multiply (Loc, Left_Opnd => Sizx, Right_Opnd => Make_Attribute_Reference (Loc, Prefix => New_Occurrence_Of (Typ, Loc), Attribute_Name => Name_Length, Expressions => New_List ( Make_Integer_Literal (Loc, J)))); Next_Index (Indx); end loop; Code := Make_Raise_Storage_Error (Loc, Condition => Make_Op_Ge (Loc, Left_Opnd => Sizx, Right_Opnd => Make_Integer_Literal (Loc, Check_Siz)), Reason => SE_Object_Too_Large); Set_Size_Check_Code (Defining_Identifier (N), Code); Insert_Action (N, Code); end Apply_Array_Size_Check; ---------------------------- -- Apply_Constraint_Check -- ---------------------------- procedure Apply_Constraint_Check (N : Node_Id; Typ : Entity_Id; No_Sliding : Boolean := False) is Desig_Typ : Entity_Id; begin if Inside_A_Generic then return; elsif Is_Scalar_Type (Typ) then Apply_Scalar_Range_Check (N, Typ); elsif Is_Array_Type (Typ) then -- A useful optimization: an aggregate with only an Others clause -- always has the right bounds. if Nkind (N) = N_Aggregate and then No (Expressions (N)) and then Nkind (First (Choices (First (Component_Associations (N))))) = N_Others_Choice then return; end if; if Is_Constrained (Typ) then Apply_Length_Check (N, Typ); if No_Sliding then Apply_Range_Check (N, Typ); end if; else Apply_Range_Check (N, Typ); end if; elsif (Is_Record_Type (Typ) or else Is_Private_Type (Typ)) and then Has_Discriminants (Base_Type (Typ)) and then Is_Constrained (Typ) then Apply_Discriminant_Check (N, Typ); elsif Is_Access_Type (Typ) then Desig_Typ := Designated_Type (Typ); -- No checks necessary if expression statically null if Nkind (N) = N_Null then null; -- No sliding possible on access to arrays elsif Is_Array_Type (Desig_Typ) then if Is_Constrained (Desig_Typ) then Apply_Length_Check (N, Typ); end if; Apply_Range_Check (N, Typ); elsif Has_Discriminants (Base_Type (Desig_Typ)) and then Is_Constrained (Desig_Typ) then Apply_Discriminant_Check (N, Typ); end if; end if; end Apply_Constraint_Check; ------------------------------ -- Apply_Discriminant_Check -- ------------------------------ procedure Apply_Discriminant_Check (N : Node_Id; Typ : Entity_Id; Lhs : Node_Id := Empty) is Loc : constant Source_Ptr := Sloc (N); Do_Access : constant Boolean := Is_Access_Type (Typ); S_Typ : Entity_Id := Etype (N); Cond : Node_Id; T_Typ : Entity_Id; function Is_Aliased_Unconstrained_Component return Boolean; -- It is possible for an aliased component to have a nominal -- unconstrained subtype (through instantiation). If this is a -- discriminated component assigned in the expansion of an aggregate -- in an initialization, the check must be suppressed. This unusual -- situation requires a predicate of its own (see 7503-008). ---------------------------------------- -- Is_Aliased_Unconstrained_Component -- ---------------------------------------- function Is_Aliased_Unconstrained_Component return Boolean is Comp : Entity_Id; Pref : Node_Id; begin if Nkind (Lhs) /= N_Selected_Component then return False; else Comp := Entity (Selector_Name (Lhs)); Pref := Prefix (Lhs); end if; if Ekind (Comp) /= E_Component or else not Is_Aliased (Comp) then return False; end if; return not Comes_From_Source (Pref) and then In_Instance and then not Is_Constrained (Etype (Comp)); end Is_Aliased_Unconstrained_Component; -- Start of processing for Apply_Discriminant_Check begin if Do_Access then T_Typ := Designated_Type (Typ); else T_Typ := Typ; end if; -- Nothing to do if discriminant checks are suppressed or else no code -- is to be generated if not Expander_Active or else Discriminant_Checks_Suppressed (T_Typ) then return; end if; -- No discriminant checks necessary for access when expression -- is statically Null. This is not only an optimization, this is -- fundamental because otherwise discriminant checks may be generated -- in init procs for types containing an access to a non-frozen yet -- record, causing a deadly forward reference. -- Also, if the expression is of an access type whose designated -- type is incomplete, then the access value must be null and -- we suppress the check. if Nkind (N) = N_Null then return; elsif Is_Access_Type (S_Typ) then S_Typ := Designated_Type (S_Typ); if Ekind (S_Typ) = E_Incomplete_Type then return; end if; end if; -- If an assignment target is present, then we need to generate -- the actual subtype if the target is a parameter or aliased -- object with an unconstrained nominal subtype. if Present (Lhs) and then (Present (Param_Entity (Lhs)) or else (not Is_Constrained (T_Typ) and then Is_Aliased_View (Lhs) and then not Is_Aliased_Unconstrained_Component)) then T_Typ := Get_Actual_Subtype (Lhs); end if; -- Nothing to do if the type is unconstrained (this is the case -- where the actual subtype in the RM sense of N is unconstrained -- and no check is required). if not Is_Constrained (T_Typ) then return; end if; -- Suppress checks if the subtypes are the same. -- the check must be preserved in an assignment to a formal, because -- the constraint is given by the actual. if Nkind (Original_Node (N)) /= N_Allocator and then (No (Lhs) or else not Is_Entity_Name (Lhs) or else (Ekind (Entity (Lhs)) /= E_In_Out_Parameter and then Ekind (Entity (Lhs)) /= E_Out_Parameter)) then if (Etype (N) = Typ or else (Do_Access and then Designated_Type (Typ) = S_Typ)) and then not Is_Aliased_View (Lhs) then return; end if; -- We can also eliminate checks on allocators with a subtype mark -- that coincides with the context type. The context type may be a -- subtype without a constraint (common case, a generic actual). elsif Nkind (Original_Node (N)) = N_Allocator and then Is_Entity_Name (Expression (Original_Node (N))) then declare Alloc_Typ : Entity_Id := Entity (Expression (Original_Node (N))); begin if Alloc_Typ = T_Typ or else (Nkind (Parent (T_Typ)) = N_Subtype_Declaration and then Is_Entity_Name ( Subtype_Indication (Parent (T_Typ))) and then Alloc_Typ = Base_Type (T_Typ)) then return; end if; end; end if; -- See if we have a case where the types are both constrained, and -- all the constraints are constants. In this case, we can do the -- check successfully at compile time. -- we skip this check for the case where the node is a rewritten` -- allocator, because it already carries the context subtype, and -- extracting the discriminants from the aggregate is messy. if Is_Constrained (S_Typ) and then Nkind (Original_Node (N)) /= N_Allocator then declare DconT : Elmt_Id; Discr : Entity_Id; DconS : Elmt_Id; ItemS : Node_Id; ItemT : Node_Id; begin -- S_Typ may not have discriminants in the case where it is a -- private type completed by a default discriminated type. In -- that case, we need to get the constraints from the -- underlying_type. If the underlying type is unconstrained (i.e. -- has no default discriminants) no check is needed. if Has_Discriminants (S_Typ) then Discr := First_Discriminant (S_Typ); DconS := First_Elmt (Discriminant_Constraint (S_Typ)); else Discr := First_Discriminant (Underlying_Type (S_Typ)); DconS := First_Elmt (Discriminant_Constraint (Underlying_Type (S_Typ))); if No (DconS) then return; end if; end if; DconT := First_Elmt (Discriminant_Constraint (T_Typ)); while Present (Discr) loop ItemS := Node (DconS); ItemT := Node (DconT); exit when not Is_OK_Static_Expression (ItemS) or else not Is_OK_Static_Expression (ItemT); if Expr_Value (ItemS) /= Expr_Value (ItemT) then if Do_Access then -- needs run-time check. exit; else Apply_Compile_Time_Constraint_Error (N, "incorrect value for discriminant&?", CE_Discriminant_Check_Failed, Ent => Discr); return; end if; end if; Next_Elmt (DconS); Next_Elmt (DconT); Next_Discriminant (Discr); end loop; if No (Discr) then return; end if; end; end if; -- Here we need a discriminant check. First build the expression -- for the comparisons of the discriminants: -- (n.disc1 /= typ.disc1) or else -- (n.disc2 /= typ.disc2) or else -- ... -- (n.discn /= typ.discn) Cond := Build_Discriminant_Checks (N, T_Typ); -- If Lhs is set and is a parameter, then the condition is -- guarded by: lhs'constrained and then (condition built above) if Present (Param_Entity (Lhs)) then Cond := Make_And_Then (Loc, Left_Opnd => Make_Attribute_Reference (Loc, Prefix => New_Occurrence_Of (Param_Entity (Lhs), Loc), Attribute_Name => Name_Constrained), Right_Opnd => Cond); end if; if Do_Access then Cond := Guard_Access (Cond, Loc, N); end if; Insert_Action (N, Make_Raise_Constraint_Error (Loc, Condition => Cond, Reason => CE_Discriminant_Check_Failed)); end Apply_Discriminant_Check; ------------------------ -- Apply_Divide_Check -- ------------------------ procedure Apply_Divide_Check (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Typ : constant Entity_Id := Etype (N); Left : constant Node_Id := Left_Opnd (N); Right : constant Node_Id := Right_Opnd (N); LLB : Uint; Llo : Uint; Lhi : Uint; LOK : Boolean; Rlo : Uint; Rhi : Uint; ROK : Boolean; begin if Expander_Active and not Backend_Divide_Checks_On_Target then Determine_Range (Right, ROK, Rlo, Rhi); -- See if division by zero possible, and if so generate test. This -- part of the test is not controlled by the -gnato switch. if Do_Division_Check (N) then if (not ROK) or else (Rlo <= 0 and then 0 <= Rhi) then Insert_Action (N, Make_Raise_Constraint_Error (Loc, Condition => Make_Op_Eq (Loc, Left_Opnd => Duplicate_Subexpr (Right), Right_Opnd => Make_Integer_Literal (Loc, 0)), Reason => CE_Divide_By_Zero)); end if; end if; -- Test for extremely annoying case of xxx'First divided by -1 if Do_Overflow_Check (N) then if Nkind (N) = N_Op_Divide and then Is_Signed_Integer_Type (Typ) then Determine_Range (Left, LOK, Llo, Lhi); LLB := Expr_Value (Type_Low_Bound (Base_Type (Typ))); if ((not ROK) or else (Rlo <= (-1) and then (-1) <= Rhi)) and then ((not LOK) or else (Llo = LLB)) then Insert_Action (N, Make_Raise_Constraint_Error (Loc, Condition => Make_And_Then (Loc, Make_Op_Eq (Loc, Left_Opnd => Duplicate_Subexpr (Left), Right_Opnd => Make_Integer_Literal (Loc, LLB)), Make_Op_Eq (Loc, Left_Opnd => Duplicate_Subexpr (Right), Right_Opnd => Make_Integer_Literal (Loc, -1))), Reason => CE_Overflow_Check_Failed)); end if; end if; end if; end if; end Apply_Divide_Check; ------------------------ -- Apply_Length_Check -- ------------------------ procedure Apply_Length_Check (Ck_Node : Node_Id; Target_Typ : Entity_Id; Source_Typ : Entity_Id := Empty) is begin Apply_Selected_Length_Checks (Ck_Node, Target_Typ, Source_Typ, Do_Static => False); end Apply_Length_Check; ----------------------- -- Apply_Range_Check -- ----------------------- procedure Apply_Range_Check (Ck_Node : Node_Id; Target_Typ : Entity_Id; Source_Typ : Entity_Id := Empty) is begin Apply_Selected_Range_Checks (Ck_Node, Target_Typ, Source_Typ, Do_Static => False); end Apply_Range_Check; ------------------------------ -- Apply_Scalar_Range_Check -- ------------------------------ -- Note that Apply_Scalar_Range_Check never turns the Do_Range_Check -- flag off if it is already set on. procedure Apply_Scalar_Range_Check (Expr : Node_Id; Target_Typ : Entity_Id; Source_Typ : Entity_Id := Empty; Fixed_Int : Boolean := False) is Parnt : constant Node_Id := Parent (Expr); S_Typ : Entity_Id; Arr : Node_Id := Empty; -- initialize to prevent warning Arr_Typ : Entity_Id := Empty; -- initialize to prevent warning OK : Boolean; Is_Subscr_Ref : Boolean; -- Set true if Expr is a subscript Is_Unconstrained_Subscr_Ref : Boolean; -- Set true if Expr is a subscript of an unconstrained array. In this -- case we do not attempt to do an analysis of the value against the -- range of the subscript, since we don't know the actual subtype. Int_Real : Boolean; -- Set to True if Expr should be regarded as a real value -- even though the type of Expr might be discrete. procedure Bad_Value; -- Procedure called if value is determined to be out of range procedure Bad_Value is begin Apply_Compile_Time_Constraint_Error (Expr, "value not in range of}?", CE_Range_Check_Failed, Ent => Target_Typ, Typ => Target_Typ); end Bad_Value; begin if Inside_A_Generic then return; -- Return if check obviously not needed. Note that we do not check -- for the expander being inactive, since this routine does not -- insert any code, but it does generate useful warnings sometimes, -- which we would like even if we are in semantics only mode. elsif Target_Typ = Any_Type or else not Is_Scalar_Type (Target_Typ) or else Raises_Constraint_Error (Expr) then return; end if; -- Now, see if checks are suppressed Is_Subscr_Ref := Is_List_Member (Expr) and then Nkind (Parnt) = N_Indexed_Component; if Is_Subscr_Ref then Arr := Prefix (Parnt); Arr_Typ := Get_Actual_Subtype_If_Available (Arr); end if; if not Do_Range_Check (Expr) then -- Subscript reference. Check for Index_Checks suppressed if Is_Subscr_Ref then -- Check array type and its base type if Index_Checks_Suppressed (Arr_Typ) or else Suppress_Index_Checks (Base_Type (Arr_Typ)) then return; -- Check array itself if it is an entity name elsif Is_Entity_Name (Arr) and then Suppress_Index_Checks (Entity (Arr)) then return; -- Check expression itself if it is an entity name elsif Is_Entity_Name (Expr) and then Suppress_Index_Checks (Entity (Expr)) then return; end if; -- All other cases, check for Range_Checks suppressed else -- Check target type and its base type if Range_Checks_Suppressed (Target_Typ) or else Suppress_Range_Checks (Base_Type (Target_Typ)) then return; -- Check expression itself if it is an entity name elsif Is_Entity_Name (Expr) and then Suppress_Range_Checks (Entity (Expr)) then return; -- If Expr is part of an assignment statement, then check -- left side of assignment if it is an entity name. elsif Nkind (Parnt) = N_Assignment_Statement and then Is_Entity_Name (Name (Parnt)) and then Suppress_Range_Checks (Entity (Name (Parnt))) then return; end if; end if; end if; -- Now see if we need a check if No (Source_Typ) then S_Typ := Etype (Expr); else S_Typ := Source_Typ; end if; if not Is_Scalar_Type (S_Typ) or else S_Typ = Any_Type then return; end if; Is_Unconstrained_Subscr_Ref := Is_Subscr_Ref and then not Is_Constrained (Arr_Typ); -- Always do a range check if the source type includes infinities -- and the target type does not include infinities. if Is_Floating_Point_Type (S_Typ) and then Has_Infinities (S_Typ) and then not Has_Infinities (Target_Typ) then Enable_Range_Check (Expr); end if; -- Return if we know expression is definitely in the range of -- the target type as determined by Determine_Range. Right now -- we only do this for discrete types, and not fixed-point or -- floating-point types. -- The additional less-precise tests below catch these cases. -- Note: skip this if we are given a source_typ, since the point -- of supplying a Source_Typ is to stop us looking at the expression. -- could sharpen this test to be out parameters only ??? if Is_Discrete_Type (Target_Typ) and then Is_Discrete_Type (Etype (Expr)) and then not Is_Unconstrained_Subscr_Ref and then No (Source_Typ) then declare Tlo : constant Node_Id := Type_Low_Bound (Target_Typ); Thi : constant Node_Id := Type_High_Bound (Target_Typ); Lo : Uint; Hi : Uint; begin if Compile_Time_Known_Value (Tlo) and then Compile_Time_Known_Value (Thi) then Determine_Range (Expr, OK, Lo, Hi); if OK then declare Lov : constant Uint := Expr_Value (Tlo); Hiv : constant Uint := Expr_Value (Thi); begin if Lo >= Lov and then Hi <= Hiv then return; elsif Lov > Hi or else Hiv < Lo then Bad_Value; return; end if; end; end if; end if; end; end if; Int_Real := Is_Floating_Point_Type (S_Typ) or else (Is_Fixed_Point_Type (S_Typ) and then not Fixed_Int); -- Check if we can determine at compile time whether Expr is in the -- range of the target type. Note that if S_Typ is within the -- bounds of Target_Typ then this must be the case. This checks is -- only meaningful if this is not a conversion between integer and -- real types. if not Is_Unconstrained_Subscr_Ref and then Is_Discrete_Type (S_Typ) = Is_Discrete_Type (Target_Typ) and then (In_Subrange_Of (S_Typ, Target_Typ, Fixed_Int) or else Is_In_Range (Expr, Target_Typ, Fixed_Int, Int_Real)) then return; elsif Is_Out_Of_Range (Expr, Target_Typ, Fixed_Int, Int_Real) then Bad_Value; return; -- Do not set range checks if they are killed elsif Nkind (Expr) = N_Unchecked_Type_Conversion and then Kill_Range_Check (Expr) then return; -- ??? We only need a runtime check if the target type is constrained -- (the predefined type Float is not for instance). -- so the following should really be -- -- elsif Is_Constrained (Target_Typ) then -- -- but it isn't because certain types do not have the Is_Constrained -- flag properly set (see 1503-003). else Enable_Range_Check (Expr); return; end if; end Apply_Scalar_Range_Check; ---------------------------------- -- Apply_Selected_Length_Checks -- ---------------------------------- procedure Apply_Selected_Length_Checks (Ck_Node : Node_Id; Target_Typ : Entity_Id; Source_Typ : Entity_Id; Do_Static : Boolean) is Cond : Node_Id; R_Result : Check_Result; R_Cno : Node_Id; Loc : constant Source_Ptr := Sloc (Ck_Node); Checks_On : constant Boolean := (not Index_Checks_Suppressed (Target_Typ)) or else (not Length_Checks_Suppressed (Target_Typ)); begin if not Expander_Active then return; end if; R_Result := Selected_Length_Checks (Ck_Node, Target_Typ, Source_Typ, Empty); for J in 1 .. 2 loop R_Cno := R_Result (J); exit when No (R_Cno); -- A length check may mention an Itype which is attached to a -- subsequent node. At the top level in a package this can cause -- an order-of-elaboration problem, so we make sure that the itype -- is referenced now. if Ekind (Current_Scope) = E_Package and then Is_Compilation_Unit (Current_Scope) then Ensure_Defined (Target_Typ, Ck_Node); if Present (Source_Typ) then Ensure_Defined (Source_Typ, Ck_Node); elsif Is_Itype (Etype (Ck_Node)) then Ensure_Defined (Etype (Ck_Node), Ck_Node); end if; end if; -- If the item is a conditional raise of constraint error, -- then have a look at what check is being performed and -- ??? if Nkind (R_Cno) = N_Raise_Constraint_Error and then Present (Condition (R_Cno)) then Cond := Condition (R_Cno); if not Has_Dynamic_Length_Check (Ck_Node) and then Checks_On then Insert_Action (Ck_Node, R_Cno); if not Do_Static then Set_Has_Dynamic_Length_Check (Ck_Node); end if; end if; -- Output a warning if the condition is known to be True if Is_Entity_Name (Cond) and then Entity (Cond) = Standard_True then Apply_Compile_Time_Constraint_Error (Ck_Node, "wrong length for array of}?", CE_Length_Check_Failed, Ent => Target_Typ, Typ => Target_Typ); -- If we were only doing a static check, or if checks are not -- on, then we want to delete the check, since it is not needed. -- We do this by replacing the if statement by a null statement elsif Do_Static or else not Checks_On then Rewrite (R_Cno, Make_Null_Statement (Loc)); end if; else Install_Static_Check (R_Cno, Loc); end if; end loop; end Apply_Selected_Length_Checks; --------------------------------- -- Apply_Selected_Range_Checks -- --------------------------------- procedure Apply_Selected_Range_Checks (Ck_Node : Node_Id; Target_Typ : Entity_Id; Source_Typ : Entity_Id; Do_Static : Boolean) is Cond : Node_Id; R_Result : Check_Result; R_Cno : Node_Id; Loc : constant Source_Ptr := Sloc (Ck_Node); Checks_On : constant Boolean := (not Index_Checks_Suppressed (Target_Typ)) or else (not Range_Checks_Suppressed (Target_Typ)); begin if not Expander_Active or else not Checks_On then return; end if; R_Result := Selected_Range_Checks (Ck_Node, Target_Typ, Source_Typ, Empty); for J in 1 .. 2 loop R_Cno := R_Result (J); exit when No (R_Cno); -- If the item is a conditional raise of constraint error, -- then have a look at what check is being performed and -- ??? if Nkind (R_Cno) = N_Raise_Constraint_Error and then Present (Condition (R_Cno)) then Cond := Condition (R_Cno); if not Has_Dynamic_Range_Check (Ck_Node) then Insert_Action (Ck_Node, R_Cno); if not Do_Static then Set_Has_Dynamic_Range_Check (Ck_Node); end if; end if; -- Output a warning if the condition is known to be True if Is_Entity_Name (Cond) and then Entity (Cond) = Standard_True then -- Since an N_Range is technically not an expression, we -- have to set one of the bounds to C_E and then just flag -- the N_Range. The warning message will point to the -- lower bound and complain about a range, which seems OK. if Nkind (Ck_Node) = N_Range then Apply_Compile_Time_Constraint_Error (Low_Bound (Ck_Node), "static range out of bounds of}?", CE_Range_Check_Failed, Ent => Target_Typ, Typ => Target_Typ); Set_Raises_Constraint_Error (Ck_Node); else Apply_Compile_Time_Constraint_Error (Ck_Node, "static value out of range of}?", CE_Range_Check_Failed, Ent => Target_Typ, Typ => Target_Typ); end if; -- If we were only doing a static check, or if checks are not -- on, then we want to delete the check, since it is not needed. -- We do this by replacing the if statement by a null statement elsif Do_Static or else not Checks_On then Rewrite (R_Cno, Make_Null_Statement (Loc)); end if; else Install_Static_Check (R_Cno, Loc); end if; end loop; end Apply_Selected_Range_Checks; ------------------------------- -- Apply_Static_Length_Check -- ------------------------------- procedure Apply_Static_Length_Check (Expr : Node_Id; Target_Typ : Entity_Id; Source_Typ : Entity_Id := Empty) is begin Apply_Selected_Length_Checks (Expr, Target_Typ, Source_Typ, Do_Static => True); end Apply_Static_Length_Check; ------------------------------------- -- Apply_Subscript_Validity_Checks -- ------------------------------------- procedure Apply_Subscript_Validity_Checks (Expr : Node_Id) is Sub : Node_Id; begin pragma Assert (Nkind (Expr) = N_Indexed_Component); -- Loop through subscripts Sub := First (Expressions (Expr)); while Present (Sub) loop -- Check one subscript. Note that we do not worry about -- enumeration type with holes, since we will convert the -- value to a Pos value for the subscript, and that convert -- will do the necessary validity check. Ensure_Valid (Sub, Holes_OK => True); -- Move to next subscript Sub := Next (Sub); end loop; end Apply_Subscript_Validity_Checks; ---------------------------------- -- Apply_Type_Conversion_Checks -- ---------------------------------- procedure Apply_Type_Conversion_Checks (N : Node_Id) is Target_Type : constant Entity_Id := Etype (N); Target_Base : constant Entity_Id := Base_Type (Target_Type); Expr : constant Node_Id := Expression (N); Expr_Type : constant Entity_Id := Etype (Expr); begin if Inside_A_Generic then return; -- Skip these checks if serious errors detected, there are some nasty -- situations of incomplete trees that blow things up. elsif Serious_Errors_Detected > 0 then return; -- Scalar type conversions of the form Target_Type (Expr) require -- two checks: -- -- - First there is an overflow check to insure that Expr is -- in the base type of Target_Typ (4.6 (28)), -- -- - After we know Expr fits into the base type, we must perform a -- range check to ensure that Expr meets the constraints of the -- Target_Type. elsif Is_Scalar_Type (Target_Type) then declare Conv_OK : constant Boolean := Conversion_OK (N); -- If the Conversion_OK flag on the type conversion is set -- and no floating point type is involved in the type conversion -- then fixed point values must be read as integral values. begin -- Overflow check. if not Overflow_Checks_Suppressed (Target_Base) and then not In_Subrange_Of (Expr_Type, Target_Base, Conv_OK) then Set_Do_Overflow_Check (N); end if; if not Range_Checks_Suppressed (Target_Type) and then not Range_Checks_Suppressed (Expr_Type) then Apply_Scalar_Range_Check (Expr, Target_Type, Fixed_Int => Conv_OK); end if; end; elsif Comes_From_Source (N) and then Is_Record_Type (Target_Type) and then Is_Derived_Type (Target_Type) and then not Is_Tagged_Type (Target_Type) and then not Is_Constrained (Target_Type) and then Present (Girder_Constraint (Target_Type)) then -- A unconstrained derived type may have inherited discriminants. -- Build an actual discriminant constraint list using the girder -- constraint, to verify that the expression of the parent type -- satisfies the constraints imposed by the (unconstrained!) -- derived type. This applies to value conversions, not to view -- conversions of tagged types. declare Loc : constant Source_Ptr := Sloc (N); Cond : Node_Id; Constraint : Elmt_Id; Discr_Value : Node_Id; Discr : Entity_Id; New_Constraints : Elist_Id := New_Elmt_List; Old_Constraints : Elist_Id := Discriminant_Constraint (Expr_Type); begin Constraint := First_Elmt (Girder_Constraint (Target_Type)); while Present (Constraint) loop Discr_Value := Node (Constraint); if Is_Entity_Name (Discr_Value) and then Ekind (Entity (Discr_Value)) = E_Discriminant then Discr := Corresponding_Discriminant (Entity (Discr_Value)); if Present (Discr) and then Scope (Discr) = Base_Type (Expr_Type) then -- Parent is constrained by new discriminant. Obtain -- Value of original discriminant in expression. If -- the new discriminant has been used to constrain more -- than one of the girder ones, this will provide the -- required consistency check. Append_Elmt ( Make_Selected_Component (Loc, Prefix => Duplicate_Subexpr (Expr, Name_Req => True), Selector_Name => Make_Identifier (Loc, Chars (Discr))), New_Constraints); else -- Discriminant of more remote ancestor ??? return; end if; -- Derived type definition has an explicit value for -- this girder discriminant. else Append_Elmt (Duplicate_Subexpr (Discr_Value), New_Constraints); end if; Next_Elmt (Constraint); end loop; -- Use the unconstrained expression type to retrieve the -- discriminants of the parent, and apply momentarily the -- discriminant constraint synthesized above. Set_Discriminant_Constraint (Expr_Type, New_Constraints); Cond := Build_Discriminant_Checks (Expr, Expr_Type); Set_Discriminant_Constraint (Expr_Type, Old_Constraints); Insert_Action (N, Make_Raise_Constraint_Error (Loc, Condition => Cond, Reason => CE_Discriminant_Check_Failed)); end; -- should there be other checks here for array types ??? else null; end if; end Apply_Type_Conversion_Checks; ---------------------------------------------- -- Apply_Universal_Integer_Attribute_Checks -- ---------------------------------------------- procedure Apply_Universal_Integer_Attribute_Checks (N : Node_Id) is Loc : constant Source_Ptr := Sloc (N); Typ : constant Entity_Id := Etype (N); begin if Inside_A_Generic then return; -- Nothing to do if checks are suppressed elsif Range_Checks_Suppressed (Typ) and then Overflow_Checks_Suppressed (Typ) then return; -- Nothing to do if the attribute does not come from source. The -- internal attributes we generate of this type do not need checks, -- and furthermore the attempt to check them causes some circular -- elaboration orders when dealing with packed types. elsif not Comes_From_Source (N) then return; -- Otherwise, replace the attribute node with a type conversion -- node whose expression is the attribute, retyped to universal -- integer, and whose subtype mark is the target type. The call -- to analyze this conversion will set range and overflow checks -- as required for proper detection of an out of range value. else Set_Etype (N, Universal_Integer); Set_Analyzed (N, True); Rewrite (N, Make_Type_Conversion (Loc, Subtype_Mark => New_Occurrence_Of (Typ, Loc), Expression => Relocate_Node (N))); Analyze_And_Resolve (N, Typ); return; end if; end Apply_Universal_Integer_Attribute_Checks; ------------------------------- -- Build_Discriminant_Checks -- ------------------------------- function Build_Discriminant_Checks (N : Node_Id; T_Typ : Entity_Id) return Node_Id is Loc : constant Source_Ptr := Sloc (N); Cond : Node_Id; Disc : Elmt_Id; Disc_Ent : Entity_Id; Dval : Node_Id; begin Cond := Empty; Disc := First_Elmt (Discriminant_Constraint (T_Typ)); -- For a fully private type, use the discriminants of the parent -- type. if Is_Private_Type (T_Typ) and then No (Full_View (T_Typ)) then Disc_Ent := First_Discriminant (Etype (Base_Type (T_Typ))); else Disc_Ent := First_Discriminant (T_Typ); end if; while Present (Disc) loop Dval := Node (Disc); if Nkind (Dval) = N_Identifier and then Ekind (Entity (Dval)) = E_Discriminant then Dval := New_Occurrence_Of (Discriminal (Entity (Dval)), Loc); else Dval := Duplicate_Subexpr (Dval); end if; Evolve_Or_Else (Cond, Make_Op_Ne (Loc, Left_Opnd => Make_Selected_Component (Loc, Prefix => Duplicate_Subexpr (N, Name_Req => True), Selector_Name => Make_Identifier (Loc, Chars (Disc_Ent))), Right_Opnd => Dval)); Next_Elmt (Disc); Next_Discriminant (Disc_Ent); end loop; return Cond; end Build_Discriminant_Checks; ----------------------------------- -- Check_Valid_Lvalue_Subscripts -- ----------------------------------- procedure Check_Valid_Lvalue_Subscripts (Expr : Node_Id) is begin -- Skip this if range checks are suppressed if Range_Checks_Suppressed (Etype (Expr)) then return; -- Only do this check for expressions that come from source. We -- assume that expander generated assignments explicitly include -- any necessary checks. Note that this is not just an optimization, -- it avoids infinite recursions! elsif not Comes_From_Source (Expr) then return; -- For a selected component, check the prefix elsif Nkind (Expr) = N_Selected_Component then Check_Valid_Lvalue_Subscripts (Prefix (Expr)); return; -- Case of indexed component elsif Nkind (Expr) = N_Indexed_Component then Apply_Subscript_Validity_Checks (Expr); -- Prefix may itself be or contain an indexed component, and -- these subscripts need checking as well Check_Valid_Lvalue_Subscripts (Prefix (Expr)); end if; end Check_Valid_Lvalue_Subscripts; --------------------- -- Determine_Range -- --------------------- Cache_Size : constant := 2 ** 10; type Cache_Index is range 0 .. Cache_Size - 1; -- Determine size of below cache (power of 2 is more efficient!) Determine_Range_Cache_N : array (Cache_Index) of Node_Id; Determine_Range_Cache_Lo : array (Cache_Index) of Uint; Determine_Range_Cache_Hi : array (Cache_Index) of Uint; -- The above arrays are used to implement a small direct cache -- for Determine_Range calls. Because of the way Determine_Range -- recursively traces subexpressions, and because overflow checking -- calls the routine on the way up the tree, a quadratic behavior -- can otherwise be encountered in large expressions. The cache -- entry for node N is stored in the (N mod Cache_Size) entry, and -- can be validated by checking the actual node value stored there. procedure Determine_Range (N : Node_Id; OK : out Boolean; Lo : out Uint; Hi : out Uint) is Typ : constant Entity_Id := Etype (N); Lo_Left : Uint; Hi_Left : Uint; -- Lo and Hi bounds of left operand Lo_Right : Uint; Hi_Right : Uint; -- Lo and Hi bounds of right (or only) operand Bound : Node_Id; -- Temp variable used to hold a bound node Hbound : Uint; -- High bound of base type of expression Lor : Uint; Hir : Uint; -- Refined values for low and high bounds, after tightening OK1 : Boolean; -- Used in lower level calls to indicate if call succeeded Cindex : Cache_Index; -- Used to search cache function OK_Operands return Boolean; -- Used for binary operators. Determines the ranges of the left and -- right operands, and if they are both OK, returns True, and puts -- the results in Lo_Right, Hi_Right, Lo_Left, Hi_Left ----------------- -- OK_Operands -- ----------------- function OK_Operands return Boolean is begin Determine_Range (Left_Opnd (N), OK1, Lo_Left, Hi_Left); if not OK1 then return False; end if; Determine_Range (Right_Opnd (N), OK1, Lo_Right, Hi_Right); return OK1; end OK_Operands; -- Start of processing for Determine_Range begin -- Prevent junk warnings by initializing range variables Lo := No_Uint; Hi := No_Uint; Lor := No_Uint; Hir := No_Uint; -- If the type is not discrete, or is undefined, then we can't -- do anything about determining the range. if No (Typ) or else not Is_Discrete_Type (Typ) or else Error_Posted (N) then OK := False; return; end if; -- For all other cases, we can determine the range OK := True; -- If value is compile time known, then the possible range is the -- one value that we know this expression definitely has! if Compile_Time_Known_Value (N) then Lo := Expr_Value (N); Hi := Lo; return; end if; -- Return if already in the cache Cindex := Cache_Index (N mod Cache_Size); if Determine_Range_Cache_N (Cindex) = N then Lo := Determine_Range_Cache_Lo (Cindex); Hi := Determine_Range_Cache_Hi (Cindex); return; end if; -- Otherwise, start by finding the bounds of the type of the -- expression, the value cannot be outside this range (if it -- is, then we have an overflow situation, which is a separate -- check, we are talking here only about the expression value). -- We use the actual bound unless it is dynamic, in which case -- use the corresponding base type bound if possible. If we can't -- get a bound then we figure we can't determine the range (a -- peculiar case, that perhaps cannot happen, but there is no -- point in bombing in this optimization circuit. -- First the low bound Bound := Type_Low_Bound (Typ); if Compile_Time_Known_Value (Bound) then Lo := Expr_Value (Bound); elsif Compile_Time_Known_Value (Type_Low_Bound (Base_Type (Typ))) then Lo := Expr_Value (Type_Low_Bound (Base_Type (Typ))); else OK := False; return; end if; -- Now the high bound Bound := Type_High_Bound (Typ); -- We need the high bound of the base type later on, and this should -- always be compile time known. Again, it is not clear that this -- can ever be false, but no point in bombing. if Compile_Time_Known_Value (Type_High_Bound (Base_Type (Typ))) then Hbound := Expr_Value (Type_High_Bound (Base_Type (Typ))); Hi := Hbound; else OK := False; return; end if; -- If we have a static subtype, then that may have a tighter bound -- so use the upper bound of the subtype instead in this case. if Compile_Time_Known_Value (Bound) then Hi := Expr_Value (Bound); end if; -- We may be able to refine this value in certain situations. If -- refinement is possible, then Lor and Hir are set to possibly -- tighter bounds, and OK1 is set to True. case Nkind (N) is -- For unary plus, result is limited by range of operand when N_Op_Plus => Determine_Range (Right_Opnd (N), OK1, Lor, Hir); -- For unary minus, determine range of operand, and negate it when N_Op_Minus => Determine_Range (Right_Opnd (N), OK1, Lo_Right, Hi_Right); if OK1 then Lor := -Hi_Right; Hir := -Lo_Right; end if; -- For binary addition, get range of each operand and do the -- addition to get the result range. when N_Op_Add => if OK_Operands then Lor := Lo_Left + Lo_Right; Hir := Hi_Left + Hi_Right; end if; -- Division is tricky. The only case we consider is where the -- right operand is a positive constant, and in this case we -- simply divide the bounds of the left operand when N_Op_Divide => if OK_Operands then if Lo_Right = Hi_Right and then Lo_Right > 0 then Lor := Lo_Left / Lo_Right; Hir := Hi_Left / Lo_Right; else OK1 := False; end if; end if; -- For binary subtraction, get range of each operand and do -- the worst case subtraction to get the result range. when N_Op_Subtract => if OK_Operands then Lor := Lo_Left - Hi_Right; Hir := Hi_Left - Lo_Right; end if; -- For MOD, if right operand is a positive constant, then -- result must be in the allowable range of mod results. when N_Op_Mod => if OK_Operands then if Lo_Right = Hi_Right then if Lo_Right > 0 then Lor := Uint_0; Hir := Lo_Right - 1; elsif Lo_Right < 0 then Lor := Lo_Right + 1; Hir := Uint_0; end if; else OK1 := False; end if; end if; -- For REM, if right operand is a positive constant, then -- result must be in the allowable range of mod results. when N_Op_Rem => if OK_Operands then if Lo_Right = Hi_Right then declare Dval : constant Uint := (abs Lo_Right) - 1; begin -- The sign of the result depends on the sign of the -- dividend (but not on the sign of the divisor, hence -- the abs operation above). if Lo_Left < 0 then Lor := -Dval; else Lor := Uint_0; end if; if Hi_Left < 0 then Hir := Uint_0; else Hir := Dval; end if; end; else OK1 := False; end if; end if; -- Attribute reference cases when N_Attribute_Reference => case Attribute_Name (N) is -- For Pos/Val attributes, we can refine the range using the -- possible range of values of the attribute expression when Name_Pos | Name_Val => Determine_Range (First (Expressions (N)), OK1, Lor, Hir); -- For Length attribute, use the bounds of the corresponding -- index type to refine the range. when Name_Length => declare Atyp : Entity_Id := Etype (Prefix (N)); Inum : Nat; Indx : Node_Id; LL, LU : Uint; UL, UU : Uint; begin if Is_Access_Type (Atyp) then Atyp := Designated_Type (Atyp); end if; -- For string literal, we know exact value if Ekind (Atyp) = E_String_Literal_Subtype then OK := True; Lo := String_Literal_Length (Atyp); Hi := String_Literal_Length (Atyp); return; end if; -- Otherwise check for expression given if No (Expressions (N)) then Inum := 1; else Inum := UI_To_Int (Expr_Value (First (Expressions (N)))); end if; Indx := First_Index (Atyp); for J in 2 .. Inum loop Indx := Next_Index (Indx); end loop; Determine_Range (Type_Low_Bound (Etype (Indx)), OK1, LL, LU); if OK1 then Determine_Range (Type_High_Bound (Etype (Indx)), OK1, UL, UU); if OK1 then -- The maximum value for Length is the biggest -- possible gap between the values of the bounds. -- But of course, this value cannot be negative. Hir := UI_Max (Uint_0, UU - LL); -- For constrained arrays, the minimum value for -- Length is taken from the actual value of the -- bounds, since the index will be exactly of -- this subtype. if Is_Constrained (Atyp) then Lor := UI_Max (Uint_0, UL - LU); -- For an unconstrained array, the minimum value -- for length is always zero. else Lor := Uint_0; end if; end if; end if; end; -- No special handling for other attributes -- Probably more opportunities exist here ??? when others => OK1 := False; end case; -- For type conversion from one discrete type to another, we -- can refine the range using the converted value. when N_Type_Conversion => Determine_Range (Expression (N), OK1, Lor, Hir); -- Nothing special to do for all other expression kinds when others => OK1 := False; Lor := No_Uint; Hir := No_Uint; end case; -- At this stage, if OK1 is true, then we know that the actual -- result of the computed expression is in the range Lor .. Hir. -- We can use this to restrict the possible range of results. if OK1 then -- If the refined value of the low bound is greater than the -- type high bound, then reset it to the more restrictive -- value. However, we do NOT do this for the case of a modular -- type where the possible upper bound on the value is above the -- base type high bound, because that means the result could wrap. if Lor > Lo and then not (Is_Modular_Integer_Type (Typ) and then Hir > Hbound) then Lo := Lor; end if; -- Similarly, if the refined value of the high bound is less -- than the value so far, then reset it to the more restrictive -- value. Again, we do not do this if the refined low bound is -- negative for a modular type, since this would wrap. if Hir < Hi and then not (Is_Modular_Integer_Type (Typ) and then Lor < Uint_0) then Hi := Hir; end if; end if; -- Set cache entry for future call and we are all done Determine_Range_Cache_N (Cindex) := N; Determine_Range_Cache_Lo (Cindex) := Lo; Determine_Range_Cache_Hi (Cindex) := Hi; return; -- If any exception occurs, it means that we have some bug in the compiler -- possibly triggered by a previous error, or by some unforseen peculiar -- occurrence. However, this is only an optimization attempt, so there is -- really no point in crashing the compiler. Instead we just decide, too -- bad, we can't figure out a range in this case after all. exception when others => -- Debug flag K disables this behavior (useful for debugging) if Debug_Flag_K then raise; else OK := False; Lo := No_Uint; Hi := No_Uint; return; end if; end Determine_Range; ------------------------------------ -- Discriminant_Checks_Suppressed -- ------------------------------------ function Discriminant_Checks_Suppressed (E : Entity_Id) return Boolean is begin return Scope_Suppress.Discriminant_Checks or else (Present (E) and then Suppress_Discriminant_Checks (E)); end Discriminant_Checks_Suppressed; -------------------------------- -- Division_Checks_Suppressed -- -------------------------------- function Division_Checks_Suppressed (E : Entity_Id) return Boolean is begin return Scope_Suppress.Division_Checks or else (Present (E) and then Suppress_Division_Checks (E)); end Division_Checks_Suppressed; ----------------------------------- -- Elaboration_Checks_Suppressed -- ----------------------------------- function Elaboration_Checks_Suppressed (E : Entity_Id) return Boolean is begin return Scope_Suppress.Elaboration_Checks or else (Present (E) and then Suppress_Elaboration_Checks (E)); end Elaboration_Checks_Suppressed; ------------------------ -- Enable_Range_Check -- ------------------------ procedure Enable_Range_Check (N : Node_Id) is begin if Nkind (N) = N_Unchecked_Type_Conversion and then Kill_Range_Check (N) then return; else Set_Do_Range_Check (N, True); end if; end Enable_Range_Check; ------------------ -- Ensure_Valid -- ------------------ procedure Ensure_Valid (Expr : Node_Id; Holes_OK : Boolean := False) is Typ : constant Entity_Id := Etype (Expr); begin -- Ignore call if we are not doing any validity checking if not Validity_Checks_On then return; -- No check required if expression is from the expander, we assume -- the expander will generate whatever checks are needed. Note that -- this is not just an optimization, it avoids infinite recursions! -- Unchecked conversions must be checked, unless they are initialized -- scalar values, as in a component assignment in an init_proc. elsif not Comes_From_Source (Expr) and then (Nkind (Expr) /= N_Unchecked_Type_Conversion or else Kill_Range_Check (Expr)) then return; -- No check required if expression is known to have valid value elsif Expr_Known_Valid (Expr) then return; -- No check required if checks off elsif Range_Checks_Suppressed (Typ) then return; -- Ignore case of enumeration with holes where the flag is set not -- to worry about holes, since no special validity check is needed elsif Is_Enumeration_Type (Typ) and then Has_Non_Standard_Rep (Typ) and then Holes_OK then return; -- No check required on the left-hand side of an assignment. elsif Nkind (Parent (Expr)) = N_Assignment_Statement and then Expr = Name (Parent (Expr)) then return; -- An annoying special case. If this is an out parameter of a scalar -- type, then the value is not going to be accessed, therefore it is -- inappropriate to do any validity check at the call site. else -- Only need to worry about scalar types if Is_Scalar_Type (Typ) then declare P : Node_Id; N : Node_Id; E : Entity_Id; F : Entity_Id; A : Node_Id; L : List_Id; begin -- Find actual argument (which may be a parameter association) -- and the parent of the actual argument (the call statement) N := Expr; P := Parent (Expr); if Nkind (P) = N_Parameter_Association then N := P; P := Parent (N); end if; -- Only need to worry if we are argument of a procedure -- call since functions don't have out parameters. if Nkind (P) = N_Procedure_Call_Statement then L := Parameter_Associations (P); E := Entity (Name (P)); -- Only need to worry if there are indeed actuals, and -- if this could be a procedure call, otherwise we cannot -- get a match (either we are not an argument, or the -- mode of the formal is not OUT). This test also filters -- out the generic case. if Is_Non_Empty_List (L) and then Is_Subprogram (E) then -- This is the loop through parameters, looking to -- see if there is an OUT parameter for which we are -- the argument. F := First_Formal (E); A := First (L); while Present (F) loop if Ekind (F) = E_Out_Parameter and then A = N then return; end if; Next_Formal (F); Next (A); end loop; end if; end if; end; end if; end if; -- If we fall through, a validity check is required. Note that it would -- not be good to set Do_Range_Check, even in contexts where this is -- permissible, since this flag causes checking against the target type, -- not the source type in contexts such as assignments Insert_Valid_Check (Expr); end Ensure_Valid; ---------------------- -- Expr_Known_Valid -- ---------------------- function Expr_Known_Valid (Expr : Node_Id) return Boolean is Typ : constant Entity_Id := Etype (Expr); begin -- Non-scalar types are always consdered valid, since they never -- give rise to the issues of erroneous or bounded error behavior -- that are the concern. In formal reference manual terms the -- notion of validity only applies to scalar types. if not Is_Scalar_Type (Typ) then return True; -- If no validity checking, then everything is considered valid elsif not Validity_Checks_On then return True; -- Floating-point types are considered valid unless floating-point -- validity checks have been specifically turned on. elsif Is_Floating_Point_Type (Typ) and then not Validity_Check_Floating_Point then return True; -- If the expression is the value of an object that is known to -- be valid, then clearly the expression value itself is valid. elsif Is_Entity_Name (Expr) and then Is_Known_Valid (Entity (Expr)) then return True; -- If the type is one for which all values are known valid, then -- we are sure that the value is valid except in the slightly odd -- case where the expression is a reference to a variable whose size -- has been explicitly set to a value greater than the object size. elsif Is_Known_Valid (Typ) then if Is_Entity_Name (Expr) and then Ekind (Entity (Expr)) = E_Variable and then Esize (Entity (Expr)) > Esize (Typ) then return False; else return True; end if; -- Integer and character literals always have valid values, where -- appropriate these will be range checked in any case. elsif Nkind (Expr) = N_Integer_Literal or else Nkind (Expr) = N_Character_Literal then return True; -- If we have a type conversion or a qualification of a known valid -- value, then the result will always be valid. elsif Nkind (Expr) = N_Type_Conversion or else Nkind (Expr) = N_Qualified_Expression then return Expr_Known_Valid (Expression (Expr)); -- The result of any function call or operator is always considered -- valid, since we assume the necessary checks are done by the call. elsif Nkind (Expr) in N_Binary_Op or else Nkind (Expr) in N_Unary_Op or else Nkind (Expr) = N_Function_Call then return True; -- For all other cases, we do not know the expression is valid else return False; end if; end Expr_Known_Valid; --------------------- -- Get_Discriminal -- --------------------- function Get_Discriminal (E : Entity_Id; Bound : Node_Id) return Node_Id is Loc : constant Source_Ptr := Sloc (E); D : Entity_Id; Sc : Entity_Id; begin -- The entity E is the type of a private component of the protected -- type, or the type of a renaming of that component within a protected -- operation of that type. Sc := Scope (E); if Ekind (Sc) /= E_Protected_Type then Sc := Scope (Sc); if Ekind (Sc) /= E_Protected_Type then return Bound; end if; end if; D := First_Discriminant (Sc); while Present (D) and then Chars (D) /= Chars (Bound) loop Next_Discriminant (D); end loop; return New_Occurrence_Of (Discriminal (D), Loc); end Get_Discriminal; ------------------ -- Guard_Access -- ------------------ function Guard_Access (Cond : Node_Id; Loc : Source_Ptr; Ck_Node : Node_Id) return Node_Id is begin if Nkind (Cond) = N_Or_Else then Set_Paren_Count (Cond, 1); end if; if Nkind (Ck_Node) = N_Allocator then return Cond; else return Make_And_Then (Loc, Left_Opnd => Make_Op_Ne (Loc, Left_Opnd => Duplicate_Subexpr (Ck_Node), Right_Opnd => Make_Null (Loc)), Right_Opnd => Cond); end if; end Guard_Access; ----------------------------- -- Index_Checks_Suppressed -- ----------------------------- function Index_Checks_Suppressed (E : Entity_Id) return Boolean is begin return Scope_Suppress.Index_Checks or else (Present (E) and then Suppress_Index_Checks (E)); end Index_Checks_Suppressed; ---------------- -- Initialize -- ---------------- procedure Initialize is begin for J in Determine_Range_Cache_N'Range loop Determine_Range_Cache_N (J) := Empty; end loop; end Initialize; ------------------------- -- Insert_Range_Checks -- ------------------------- procedure Insert_Range_Checks (Checks : Check_Result; Node : Node_Id; Suppress_Typ : Entity_Id; Static_Sloc : Source_Ptr := No_Location; Flag_Node : Node_Id := Empty; Do_Before : Boolean := False) is Internal_Flag_Node : Node_Id := Flag_Node; Internal_Static_Sloc : Source_Ptr := Static_Sloc; Check_Node : Node_Id; Checks_On : constant Boolean := (not Index_Checks_Suppressed (Suppress_Typ)) or else (not Range_Checks_Suppressed (Suppress_Typ)); begin -- For now we just return if Checks_On is false, however this should -- be enhanced to check for an always True value in the condition -- and to generate a compilation warning??? if not Expander_Active or else not Checks_On then return; end if; if Static_Sloc = No_Location then Internal_Static_Sloc := Sloc (Node); end if; if No (Flag_Node) then Internal_Flag_Node := Node; end if; for J in 1 .. 2 loop exit when No (Checks (J)); if Nkind (Checks (J)) = N_Raise_Constraint_Error and then Present (Condition (Checks (J))) then if not Has_Dynamic_Range_Check (Internal_Flag_Node) then Check_Node := Checks (J); Mark_Rewrite_Insertion (Check_Node); if Do_Before then Insert_Before_And_Analyze (Node, Check_Node); else Insert_After_And_Analyze (Node, Check_Node); end if; Set_Has_Dynamic_Range_Check (Internal_Flag_Node); end if; else Check_Node := Make_Raise_Constraint_Error (Internal_Static_Sloc, Reason => CE_Range_Check_Failed); Mark_Rewrite_Insertion (Check_Node); if Do_Before then Insert_Before_And_Analyze (Node, Check_Node); else Insert_After_And_Analyze (Node, Check_Node); end if; end if; end loop; end Insert_Range_Checks; ------------------------ -- Insert_Valid_Check -- ------------------------ procedure Insert_Valid_Check (Expr : Node_Id) is Loc : constant Source_Ptr := Sloc (Expr); Exp : Node_Id; begin -- Do not insert if checks off, or if not checking validity if Range_Checks_Suppressed (Etype (Expr)) or else (not Validity_Checks_On) then return; end if; -- If we have a checked conversion, then validity check applies to -- the expression inside the conversion, not the result, since if -- the expression inside is valid, then so is the conversion result. Exp := Expr; while Nkind (Exp) = N_Type_Conversion loop Exp := Expression (Exp); end loop; -- Insert the validity check. Note that we do this with validity -- checks turned off, to avoid recursion, we do not want validity -- checks on the validity checking code itself! Validity_Checks_On := False; Insert_Action (Expr, Make_Raise_Constraint_Error (Loc, Condition => Make_Op_Not (Loc, Right_Opnd => Make_Attribute_Reference (Loc, Prefix => Duplicate_Subexpr (Exp, Name_Req => True), Attribute_Name => Name_Valid)), Reason => CE_Invalid_Data), Suppress => All_Checks); Validity_Checks_On := True; end Insert_Valid_Check; -------------------------- -- Install_Static_Check -- -------------------------- procedure Install_Static_Check (R_Cno : Node_Id; Loc : Source_Ptr) is Stat : constant Boolean := Is_Static_Expression (R_Cno); Typ : constant Entity_Id := Etype (R_Cno); begin Rewrite (R_Cno, Make_Raise_Constraint_Error (Loc, Reason => CE_Range_Check_Failed)); Set_Analyzed (R_Cno); Set_Etype (R_Cno, Typ); Set_Raises_Constraint_Error (R_Cno); Set_Is_Static_Expression (R_Cno, Stat); end Install_Static_Check; ------------------------------ -- Length_Checks_Suppressed -- ------------------------------ function Length_Checks_Suppressed (E : Entity_Id) return Boolean is begin return Scope_Suppress.Length_Checks or else (Present (E) and then Suppress_Length_Checks (E)); end Length_Checks_Suppressed; -------------------------------- -- Overflow_Checks_Suppressed -- -------------------------------- function Overflow_Checks_Suppressed (E : Entity_Id) return Boolean is begin return Scope_Suppress.Overflow_Checks or else (Present (E) and then Suppress_Overflow_Checks (E)); end Overflow_Checks_Suppressed; ----------------- -- Range_Check -- ----------------- function Range_Check (Ck_Node : Node_Id; Target_Typ : Entity_Id; Source_Typ : Entity_Id := Empty; Warn_Node : Node_Id := Empty) return Check_Result is begin return Selected_Range_Checks (Ck_Node, Target_Typ, Source_Typ, Warn_Node); end Range_Check; ----------------------------- -- Range_Checks_Suppressed -- ----------------------------- function Range_Checks_Suppressed (E : Entity_Id) return Boolean is begin -- Note: for now we always suppress range checks on Vax float types, -- since Gigi does not know how to generate these checks. return Scope_Suppress.Range_Checks or else (Present (E) and then Suppress_Range_Checks (E)) or else Vax_Float (E); end Range_Checks_Suppressed; ------------------- -- Remove_Checks -- ------------------- procedure Remove_Checks (Expr : Node_Id) is Discard : Traverse_Result; function Process (N : Node_Id) return Traverse_Result; -- Process a single node during the traversal function Traverse is new Traverse_Func (Process); -- The traversal function itself ------------- -- Process -- ------------- function Process (N : Node_Id) return Traverse_Result is begin if Nkind (N) not in N_Subexpr then return Skip; end if; Set_Do_Range_Check (N, False); case Nkind (N) is when N_And_Then => Discard := Traverse (Left_Opnd (N)); return Skip; when N_Attribute_Reference => Set_Do_Access_Check (N, False); Set_Do_Overflow_Check (N, False); when N_Explicit_Dereference => Set_Do_Access_Check (N, False); when N_Function_Call => Set_Do_Tag_Check (N, False); when N_Indexed_Component => Set_Do_Access_Check (N, False); when N_Op => Set_Do_Overflow_Check (N, False); case Nkind (N) is when N_Op_Divide => Set_Do_Division_Check (N, False); when N_Op_And => Set_Do_Length_Check (N, False); when N_Op_Mod => Set_Do_Division_Check (N, False); when N_Op_Or => Set_Do_Length_Check (N, False); when N_Op_Rem => Set_Do_Division_Check (N, False); when N_Op_Xor => Set_Do_Length_Check (N, False); when others => null; end case; when N_Or_Else => Discard := Traverse (Left_Opnd (N)); return Skip; when N_Selected_Component => Set_Do_Access_Check (N, False); Set_Do_Discriminant_Check (N, False); when N_Slice => Set_Do_Access_Check (N, False); when N_Type_Conversion => Set_Do_Length_Check (N, False); Set_Do_Overflow_Check (N, False); Set_Do_Tag_Check (N, False); when others => null; end case; return OK; end Process; -- Start of processing for Remove_Checks begin Discard := Traverse (Expr); end Remove_Checks; ---------------------------- -- Selected_Length_Checks -- ---------------------------- function Selected_Length_Checks (Ck_Node : Node_Id; Target_Typ : Entity_Id; Source_Typ : Entity_Id; Warn_Node : Node_Id) return Check_Result is Loc : constant Source_Ptr := Sloc (Ck_Node); S_Typ : Entity_Id; T_Typ : Entity_Id; Expr_Actual : Node_Id; Exptyp : Entity_Id; Cond : Node_Id := Empty; Do_Access : Boolean := False; Wnode : Node_Id := Warn_Node; Ret_Result : Check_Result := (Empty, Empty); Num_Checks : Natural := 0; procedure Add_Check (N : Node_Id); -- Adds the action given to Ret_Result if N is non-Empty function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id; function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id; function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean; -- True for equal literals and for nodes that denote the same constant -- entity, even if its value is not a static constant. This includes the -- case of a discriminal reference within an init_proc. Removes some -- obviously superfluous checks. function Length_E_Cond (Exptyp : Entity_Id; Typ : Entity_Id; Indx : Nat) return Node_Id; -- Returns expression to compute: -- Typ'Length /= Exptyp'Length function Length_N_Cond (Expr : Node_Id; Typ : Entity_Id; Indx : Nat) return Node_Id; -- Returns expression to compute: -- Typ'Length /= Expr'Length --------------- -- Add_Check -- --------------- procedure Add_Check (N : Node_Id) is begin if Present (N) then -- For now, ignore attempt to place more than 2 checks ??? if Num_Checks = 2 then return; end if; pragma Assert (Num_Checks <= 1); Num_Checks := Num_Checks + 1; Ret_Result (Num_Checks) := N; end if; end Add_Check; ------------------ -- Get_E_Length -- ------------------ function Get_E_Length (E : Entity_Id; Indx : Nat) return Node_Id is N : Node_Id; E1 : Entity_Id := E; Pt : Entity_Id := Scope (Scope (E)); begin if Ekind (Scope (E)) = E_Record_Type and then Has_Discriminants (Scope (E)) then N := Build_Discriminal_Subtype_Of_Component (E); if Present (N) then Insert_Action (Ck_Node, N); E1 := Defining_Identifier (N); end if; end if; if Ekind (E1) = E_String_Literal_Subtype then return Make_Integer_Literal (Loc, Intval => String_Literal_Length (E1)); elsif Ekind (Pt) = E_Protected_Type and then Has_Discriminants (Pt) and then Has_Completion (Pt) and then not Inside_Init_Proc then -- If the type whose length is needed is a private component -- constrained by a discriminant, we must expand the 'Length -- attribute into an explicit computation, using the discriminal -- of the current protected operation. This is because the actual -- type of the prival is constructed after the protected opera- -- tion has been fully expanded. declare Indx_Type : Node_Id; Lo : Node_Id; Hi : Node_Id; Do_Expand : Boolean := False; begin Indx_Type := First_Index (E); for J in 1 .. Indx - 1 loop Next_Index (Indx_Type); end loop; Get_Index_Bounds (Indx_Type, Lo, Hi); if Nkind (Lo) = N_Identifier and then Ekind (Entity (Lo)) = E_In_Parameter then Lo := Get_Discriminal (E, Lo); Do_Expand := True; end if; if Nkind (Hi) = N_Identifier and then Ekind (Entity (Hi)) = E_In_Parameter then Hi := Get_Discriminal (E, Hi); Do_Expand := True; end if; if Do_Expand then if not Is_Entity_Name (Lo) then Lo := Duplicate_Subexpr (Lo); end if; if not Is_Entity_Name (Hi) then Lo := Duplicate_Subexpr (Hi); end if; N := Make_Op_Add (Loc, Left_Opnd => Make_Op_Subtract (Loc, Left_Opnd => Hi, Right_Opnd => Lo), Right_Opnd => Make_Integer_Literal (Loc, 1)); return N; else N := Make_Attribute_Reference (Loc, Attribute_Name => Name_Length, Prefix => New_Occurrence_Of (E1, Loc)); if Indx > 1 then Set_Expressions (N, New_List ( Make_Integer_Literal (Loc, Indx))); end if; return N; end if; end; else N := Make_Attribute_Reference (Loc, Attribute_Name => Name_Length, Prefix => New_Occurrence_Of (E1, Loc)); if Indx > 1 then Set_Expressions (N, New_List ( Make_Integer_Literal (Loc, Indx))); end if; return N; end if; end Get_E_Length; ------------------ -- Get_N_Length -- ------------------ function Get_N_Length (N : Node_Id; Indx : Nat) return Node_Id is begin return Make_Attribute_Reference (Loc, Attribute_Name => Name_Length, Prefix => Duplicate_Subexpr (N, Name_Req => True), Expressions => New_List ( Make_Integer_Literal (Loc, Indx))); end Get_N_Length; ------------------- -- Length_E_Cond -- ------------------- function Length_E_Cond (Exptyp : Entity_Id; Typ : Entity_Id; Indx : Nat) return Node_Id is begin return Make_Op_Ne (Loc, Left_Opnd => Get_E_Length (Typ, Indx), Right_Opnd => Get_E_Length (Exptyp, Indx)); end Length_E_Cond; ------------------- -- Length_N_Cond -- ------------------- function Length_N_Cond (Expr : Node_Id; Typ : Entity_Id; Indx : Nat) return Node_Id is begin return Make_Op_Ne (Loc, Left_Opnd => Get_E_Length (Typ, Indx), Right_Opnd => Get_N_Length (Expr, Indx)); end Length_N_Cond; function Same_Bounds (L : Node_Id; R : Node_Id) return Boolean is begin return (Nkind (L) = N_Integer_Literal and then Nkind (R) = N_Integer_Literal and then Intval (L) = Intval (R)) or else (Is_Entity_Name (L) and then Ekind (Entity (L)) = E_Constant and then ((Is_Entity_Name (R) and then Entity (L) = Entity (R)) or else (Nkind (R) = N_Type_Conversion and then Is_Entity_Name (Expression (R)) and then Entity (L) = Entity (Expression (R))))) or else (Is_Entity_Name (R) and then Ekind (Entity (R)) = E_Constant and then Nkind (L) = N_Type_Conversion and then Is_Entity_Name (Expression (L)) and then Entity (R) = Entity (Expression (L))) or else (Is_Entity_Name (L) and then Is_Entity_Name (R) and then Entity (L) = Entity (R) and then Ekind (Entity (L)) = E_In_Parameter and then Inside_Init_Proc); end Same_Bounds; -- Start of processing for Selected_Length_Checks begin if not Expander_Active then return Ret_Result; end if; if Target_Typ = Any_Type or else Target_Typ = Any_Composite or else Raises_Constraint_Error (Ck_Node) then return Ret_Result; end if; if No (Wnode) then Wnode := Ck_Node; end if; T_Typ := Target_Typ; if No (Source_Typ) then S_Typ := Etype (Ck_Node); else S_Typ := Source_Typ; end if; if S_Typ = Any_Type or else S_Typ = Any_Composite then return Ret_Result; end if; if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then S_Typ := Designated_Type (S_Typ); T_Typ := Designated_Type (T_Typ); Do_Access := True; -- A simple optimization if Nkind (Ck_Node) = N_Null then return Ret_Result; end if; end if; if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then if Is_Constrained (T_Typ) then -- The checking code to be generated will freeze the -- corresponding array type. However, we must freeze the -- type now, so that the freeze node does not appear within -- the generated condional expression, but ahead of it. Freeze_Before (Ck_Node, T_Typ); Expr_Actual := Get_Referenced_Object (Ck_Node); Exptyp := Get_Actual_Subtype (Expr_Actual); if Is_Access_Type (Exptyp) then Exptyp := Designated_Type (Exptyp); end if; -- String_Literal case. This needs to be handled specially be- -- cause no index types are available for string literals. The -- condition is simply: -- T_Typ'Length = string-literal-length if Nkind (Expr_Actual) = N_String_Literal then Cond := Make_Op_Ne (Loc, Left_Opnd => Get_E_Length (T_Typ, 1), Right_Opnd => Make_Integer_Literal (Loc, Intval => String_Literal_Length (Etype (Expr_Actual)))); -- General array case. Here we have a usable actual subtype for -- the expression, and the condition is built from the two types -- (Do_Length): -- T_Typ'Length /= Exptyp'Length or else -- T_Typ'Length (2) /= Exptyp'Length (2) or else -- T_Typ'Length (3) /= Exptyp'Length (3) or else -- ... elsif Is_Constrained (Exptyp) then declare L_Index : Node_Id; R_Index : Node_Id; Ndims : Nat := Number_Dimensions (T_Typ); L_Low : Node_Id; L_High : Node_Id; R_Low : Node_Id; R_High : Node_Id; L_Length : Uint; R_Length : Uint; begin L_Index := First_Index (T_Typ); R_Index := First_Index (Exptyp); for Indx in 1 .. Ndims loop if not (Nkind (L_Index) = N_Raise_Constraint_Error or else Nkind (R_Index) = N_Raise_Constraint_Error) then Get_Index_Bounds (L_Index, L_Low, L_High); Get_Index_Bounds (R_Index, R_Low, R_High); -- Deal with compile time length check. Note that we -- skip this in the access case, because the access -- value may be null, so we cannot know statically. if not Do_Access and then Compile_Time_Known_Value (L_Low) and then Compile_Time_Known_Value (L_High) and then Compile_Time_Known_Value (R_Low) and then Compile_Time_Known_Value (R_High) then if Expr_Value (L_High) >= Expr_Value (L_Low) then L_Length := Expr_Value (L_High) - Expr_Value (L_Low) + 1; else L_Length := UI_From_Int (0); end if; if Expr_Value (R_High) >= Expr_Value (R_Low) then R_Length := Expr_Value (R_High) - Expr_Value (R_Low) + 1; else R_Length := UI_From_Int (0); end if; if L_Length > R_Length then Add_Check (Compile_Time_Constraint_Error (Wnode, "too few elements for}?", T_Typ)); elsif L_Length < R_Length then Add_Check (Compile_Time_Constraint_Error (Wnode, "too many elements for}?", T_Typ)); end if; -- The comparison for an individual index subtype -- is omitted if the corresponding index subtypes -- statically match, since the result is known to -- be true. Note that this test is worth while even -- though we do static evaluation, because non-static -- subtypes can statically match. elsif not Subtypes_Statically_Match (Etype (L_Index), Etype (R_Index)) and then not (Same_Bounds (L_Low, R_Low) and then Same_Bounds (L_High, R_High)) then Evolve_Or_Else (Cond, Length_E_Cond (Exptyp, T_Typ, Indx)); end if; Next (L_Index); Next (R_Index); end if; end loop; end; -- Handle cases where we do not get a usable actual subtype that -- is constrained. This happens for example in the function call -- and explicit dereference cases. In these cases, we have to get -- the length or range from the expression itself, making sure we -- do not evaluate it more than once. -- Here Ck_Node is the original expression, or more properly the -- result of applying Duplicate_Expr to the original tree, -- forcing the result to be a name. else declare Ndims : Nat := Number_Dimensions (T_Typ); begin -- Build the condition for the explicit dereference case for Indx in 1 .. Ndims loop Evolve_Or_Else (Cond, Length_N_Cond (Ck_Node, T_Typ, Indx)); end loop; end; end if; end if; end if; -- Construct the test and insert into the tree if Present (Cond) then if Do_Access then Cond := Guard_Access (Cond, Loc, Ck_Node); end if; Add_Check (Make_Raise_Constraint_Error (Loc, Condition => Cond, Reason => CE_Length_Check_Failed)); end if; return Ret_Result; end Selected_Length_Checks; --------------------------- -- Selected_Range_Checks -- --------------------------- function Selected_Range_Checks (Ck_Node : Node_Id; Target_Typ : Entity_Id; Source_Typ : Entity_Id; Warn_Node : Node_Id) return Check_Result is Loc : constant Source_Ptr := Sloc (Ck_Node); S_Typ : Entity_Id; T_Typ : Entity_Id; Expr_Actual : Node_Id; Exptyp : Entity_Id; Cond : Node_Id := Empty; Do_Access : Boolean := False; Wnode : Node_Id := Warn_Node; Ret_Result : Check_Result := (Empty, Empty); Num_Checks : Integer := 0; procedure Add_Check (N : Node_Id); -- Adds the action given to Ret_Result if N is non-Empty function Discrete_Range_Cond (Expr : Node_Id; Typ : Entity_Id) return Node_Id; -- Returns expression to compute: -- Low_Bound (Expr) < Typ'First -- or else -- High_Bound (Expr) > Typ'Last function Discrete_Expr_Cond (Expr : Node_Id; Typ : Entity_Id) return Node_Id; -- Returns expression to compute: -- Expr < Typ'First -- or else -- Expr > Typ'Last function Get_E_First_Or_Last (E : Entity_Id; Indx : Nat; Nam : Name_Id) return Node_Id; -- Returns expression to compute: -- E'First or E'Last function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id; function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id; -- Returns expression to compute: -- N'First or N'Last using Duplicate_Subexpr function Range_E_Cond (Exptyp : Entity_Id; Typ : Entity_Id; Indx : Nat) return Node_Id; -- Returns expression to compute: -- Exptyp'First < Typ'First or else Exptyp'Last > Typ'Last function Range_Equal_E_Cond (Exptyp : Entity_Id; Typ : Entity_Id; Indx : Nat) return Node_Id; -- Returns expression to compute: -- Exptyp'First /= Typ'First or else Exptyp'Last /= Typ'Last function Range_N_Cond (Expr : Node_Id; Typ : Entity_Id; Indx : Nat) return Node_Id; -- Return expression to compute: -- Expr'First < Typ'First or else Expr'Last > Typ'Last --------------- -- Add_Check -- --------------- procedure Add_Check (N : Node_Id) is begin if Present (N) then -- For now, ignore attempt to place more than 2 checks ??? if Num_Checks = 2 then return; end if; pragma Assert (Num_Checks <= 1); Num_Checks := Num_Checks + 1; Ret_Result (Num_Checks) := N; end if; end Add_Check; ------------------------- -- Discrete_Expr_Cond -- ------------------------- function Discrete_Expr_Cond (Expr : Node_Id; Typ : Entity_Id) return Node_Id is begin return Make_Or_Else (Loc, Left_Opnd => Make_Op_Lt (Loc, Left_Opnd => Convert_To (Base_Type (Typ), Duplicate_Subexpr (Expr)), Right_Opnd => Convert_To (Base_Type (Typ), Get_E_First_Or_Last (Typ, 0, Name_First))), Right_Opnd => Make_Op_Gt (Loc, Left_Opnd => Convert_To (Base_Type (Typ), Duplicate_Subexpr (Expr)), Right_Opnd => Convert_To (Base_Type (Typ), Get_E_First_Or_Last (Typ, 0, Name_Last)))); end Discrete_Expr_Cond; ------------------------- -- Discrete_Range_Cond -- ------------------------- function Discrete_Range_Cond (Expr : Node_Id; Typ : Entity_Id) return Node_Id is LB : Node_Id := Low_Bound (Expr); HB : Node_Id := High_Bound (Expr); Left_Opnd : Node_Id; Right_Opnd : Node_Id; begin if Nkind (LB) = N_Identifier and then Ekind (Entity (LB)) = E_Discriminant then LB := New_Occurrence_Of (Discriminal (Entity (LB)), Loc); end if; if Nkind (HB) = N_Identifier and then Ekind (Entity (HB)) = E_Discriminant then HB := New_Occurrence_Of (Discriminal (Entity (HB)), Loc); end if; Left_Opnd := Make_Op_Lt (Loc, Left_Opnd => Convert_To (Base_Type (Typ), Duplicate_Subexpr (LB)), Right_Opnd => Convert_To (Base_Type (Typ), Get_E_First_Or_Last (Typ, 0, Name_First))); if Base_Type (Typ) = Typ then return Left_Opnd; elsif Compile_Time_Known_Value (High_Bound (Scalar_Range (Typ))) and then Compile_Time_Known_Value (High_Bound (Scalar_Range (Base_Type (Typ)))) then if Is_Floating_Point_Type (Typ) then if Expr_Value_R (High_Bound (Scalar_Range (Typ))) = Expr_Value_R (High_Bound (Scalar_Range (Base_Type (Typ)))) then return Left_Opnd; end if; else if Expr_Value (High_Bound (Scalar_Range (Typ))) = Expr_Value (High_Bound (Scalar_Range (Base_Type (Typ)))) then return Left_Opnd; end if; end if; end if; Right_Opnd := Make_Op_Gt (Loc, Left_Opnd => Convert_To (Base_Type (Typ), Duplicate_Subexpr (HB)), Right_Opnd => Convert_To (Base_Type (Typ), Get_E_First_Or_Last (Typ, 0, Name_Last))); return Make_Or_Else (Loc, Left_Opnd, Right_Opnd); end Discrete_Range_Cond; ------------------------- -- Get_E_First_Or_Last -- ------------------------- function Get_E_First_Or_Last (E : Entity_Id; Indx : Nat; Nam : Name_Id) return Node_Id is N : Node_Id; LB : Node_Id; HB : Node_Id; Bound : Node_Id; begin if Is_Array_Type (E) then N := First_Index (E); for J in 2 .. Indx loop Next_Index (N); end loop; else N := Scalar_Range (E); end if; if Nkind (N) = N_Subtype_Indication then LB := Low_Bound (Range_Expression (Constraint (N))); HB := High_Bound (Range_Expression (Constraint (N))); elsif Is_Entity_Name (N) then LB := Type_Low_Bound (Etype (N)); HB := Type_High_Bound (Etype (N)); else LB := Low_Bound (N); HB := High_Bound (N); end if; if Nam = Name_First then Bound := LB; else Bound := HB; end if; if Nkind (Bound) = N_Identifier and then Ekind (Entity (Bound)) = E_Discriminant then return New_Occurrence_Of (Discriminal (Entity (Bound)), Loc); elsif Nkind (Bound) = N_Identifier and then Ekind (Entity (Bound)) = E_In_Parameter and then not Inside_Init_Proc then return Get_Discriminal (E, Bound); elsif Nkind (Bound) = N_Integer_Literal then return Make_Integer_Literal (Loc, Intval (Bound)); else return Duplicate_Subexpr (Bound); end if; end Get_E_First_Or_Last; ----------------- -- Get_N_First -- ----------------- function Get_N_First (N : Node_Id; Indx : Nat) return Node_Id is begin return Make_Attribute_Reference (Loc, Attribute_Name => Name_First, Prefix => Duplicate_Subexpr (N, Name_Req => True), Expressions => New_List ( Make_Integer_Literal (Loc, Indx))); end Get_N_First; ---------------- -- Get_N_Last -- ---------------- function Get_N_Last (N : Node_Id; Indx : Nat) return Node_Id is begin return Make_Attribute_Reference (Loc, Attribute_Name => Name_Last, Prefix => Duplicate_Subexpr (N, Name_Req => True), Expressions => New_List ( Make_Integer_Literal (Loc, Indx))); end Get_N_Last; ------------------ -- Range_E_Cond -- ------------------ function Range_E_Cond (Exptyp : Entity_Id; Typ : Entity_Id; Indx : Nat) return Node_Id is begin return Make_Or_Else (Loc, Left_Opnd => Make_Op_Lt (Loc, Left_Opnd => Get_E_First_Or_Last (Exptyp, Indx, Name_First), Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_First)), Right_Opnd => Make_Op_Gt (Loc, Left_Opnd => Get_E_First_Or_Last (Exptyp, Indx, Name_Last), Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_Last))); end Range_E_Cond; ------------------------ -- Range_Equal_E_Cond -- ------------------------ function Range_Equal_E_Cond (Exptyp : Entity_Id; Typ : Entity_Id; Indx : Nat) return Node_Id is begin return Make_Or_Else (Loc, Left_Opnd => Make_Op_Ne (Loc, Left_Opnd => Get_E_First_Or_Last (Exptyp, Indx, Name_First), Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_First)), Right_Opnd => Make_Op_Ne (Loc, Left_Opnd => Get_E_First_Or_Last (Exptyp, Indx, Name_Last), Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_Last))); end Range_Equal_E_Cond; ------------------ -- Range_N_Cond -- ------------------ function Range_N_Cond (Expr : Node_Id; Typ : Entity_Id; Indx : Nat) return Node_Id is begin return Make_Or_Else (Loc, Left_Opnd => Make_Op_Lt (Loc, Left_Opnd => Get_N_First (Expr, Indx), Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_First)), Right_Opnd => Make_Op_Gt (Loc, Left_Opnd => Get_N_Last (Expr, Indx), Right_Opnd => Get_E_First_Or_Last (Typ, Indx, Name_Last))); end Range_N_Cond; -- Start of processing for Selected_Range_Checks begin if not Expander_Active then return Ret_Result; end if; if Target_Typ = Any_Type or else Target_Typ = Any_Composite or else Raises_Constraint_Error (Ck_Node) then return Ret_Result; end if; if No (Wnode) then Wnode := Ck_Node; end if; T_Typ := Target_Typ; if No (Source_Typ) then S_Typ := Etype (Ck_Node); else S_Typ := Source_Typ; end if; if S_Typ = Any_Type or else S_Typ = Any_Composite then return Ret_Result; end if; -- The order of evaluating T_Typ before S_Typ seems to be critical -- because S_Typ can be derived from Etype (Ck_Node), if it's not passed -- in, and since Node can be an N_Range node, it might be invalid. -- Should there be an assert check somewhere for taking the Etype of -- an N_Range node ??? if Is_Access_Type (T_Typ) and then Is_Access_Type (S_Typ) then S_Typ := Designated_Type (S_Typ); T_Typ := Designated_Type (T_Typ); Do_Access := True; -- A simple optimization if Nkind (Ck_Node) = N_Null then return Ret_Result; end if; end if; -- For an N_Range Node, check for a null range and then if not -- null generate a range check action. if Nkind (Ck_Node) = N_Range then -- There's no point in checking a range against itself if Ck_Node = Scalar_Range (T_Typ) then return Ret_Result; end if; declare T_LB : constant Node_Id := Type_Low_Bound (T_Typ); T_HB : constant Node_Id := Type_High_Bound (T_Typ); LB : constant Node_Id := Low_Bound (Ck_Node); HB : constant Node_Id := High_Bound (Ck_Node); Null_Range : Boolean; Out_Of_Range_L : Boolean; Out_Of_Range_H : Boolean; begin -- Check for case where everything is static and we can -- do the check at compile time. This is skipped if we -- have an access type, since the access value may be null. -- ??? This code can be improved since you only need to know -- that the two respective bounds (LB & T_LB or HB & T_HB) -- are known at compile time to emit pertinent messages. if Compile_Time_Known_Value (LB) and then Compile_Time_Known_Value (HB) and then Compile_Time_Known_Value (T_LB) and then Compile_Time_Known_Value (T_HB) and then not Do_Access then -- Floating-point case if Is_Floating_Point_Type (S_Typ) then Null_Range := Expr_Value_R (HB) < Expr_Value_R (LB); Out_Of_Range_L := (Expr_Value_R (LB) < Expr_Value_R (T_LB)) or else (Expr_Value_R (LB) > Expr_Value_R (T_HB)); Out_Of_Range_H := (Expr_Value_R (HB) > Expr_Value_R (T_HB)) or else (Expr_Value_R (HB) < Expr_Value_R (T_LB)); -- Fixed or discrete type case else Null_Range := Expr_Value (HB) < Expr_Value (LB); Out_Of_Range_L := (Expr_Value (LB) < Expr_Value (T_LB)) or else (Expr_Value (LB) > Expr_Value (T_HB)); Out_Of_Range_H := (Expr_Value (HB) > Expr_Value (T_HB)) or else (Expr_Value (HB) < Expr_Value (T_LB)); end if; if not Null_Range then if Out_Of_Range_L then if No (Warn_Node) then Add_Check (Compile_Time_Constraint_Error (Low_Bound (Ck_Node), "static value out of range of}?", T_Typ)); else Add_Check (Compile_Time_Constraint_Error (Wnode, "static range out of bounds of}?", T_Typ)); end if; end if; if Out_Of_Range_H then if No (Warn_Node) then Add_Check (Compile_Time_Constraint_Error (High_Bound (Ck_Node), "static value out of range of}?", T_Typ)); else Add_Check (Compile_Time_Constraint_Error (Wnode, "static range out of bounds of}?", T_Typ)); end if; end if; end if; else declare LB : Node_Id := Low_Bound (Ck_Node); HB : Node_Id := High_Bound (Ck_Node); begin -- If either bound is a discriminant and we are within -- the record declaration, it is a use of the discriminant -- in a constraint of a component, and nothing can be -- checked here. The check will be emitted within the -- init_proc. Before then, the discriminal has no real -- meaning. if Nkind (LB) = N_Identifier and then Ekind (Entity (LB)) = E_Discriminant then if Current_Scope = Scope (Entity (LB)) then return Ret_Result; else LB := New_Occurrence_Of (Discriminal (Entity (LB)), Loc); end if; end if; if Nkind (HB) = N_Identifier and then Ekind (Entity (HB)) = E_Discriminant then if Current_Scope = Scope (Entity (HB)) then return Ret_Result; else HB := New_Occurrence_Of (Discriminal (Entity (HB)), Loc); end if; end if; Cond := Discrete_Range_Cond (Ck_Node, T_Typ); Set_Paren_Count (Cond, 1); Cond := Make_And_Then (Loc, Left_Opnd => Make_Op_Ge (Loc, Left_Opnd => Duplicate_Subexpr (HB), Right_Opnd => Duplicate_Subexpr (LB)), Right_Opnd => Cond); end; end if; end; elsif Is_Scalar_Type (S_Typ) then -- This somewhat duplicates what Apply_Scalar_Range_Check does, -- except the above simply sets a flag in the node and lets -- gigi generate the check base on the Etype of the expression. -- Sometimes, however we want to do a dynamic check against an -- arbitrary target type, so we do that here. if Ekind (Base_Type (S_Typ)) /= Ekind (Base_Type (T_Typ)) then Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); -- For literals, we can tell if the constraint error will be -- raised at compile time, so we never need a dynamic check, but -- if the exception will be raised, then post the usual warning, -- and replace the literal with a raise constraint error -- expression. As usual, skip this for access types elsif Compile_Time_Known_Value (Ck_Node) and then not Do_Access then declare LB : constant Node_Id := Type_Low_Bound (T_Typ); UB : constant Node_Id := Type_High_Bound (T_Typ); Out_Of_Range : Boolean; Static_Bounds : constant Boolean := Compile_Time_Known_Value (LB) and Compile_Time_Known_Value (UB); begin -- Following range tests should use Sem_Eval routine ??? if Static_Bounds then if Is_Floating_Point_Type (S_Typ) then Out_Of_Range := (Expr_Value_R (Ck_Node) < Expr_Value_R (LB)) or else (Expr_Value_R (Ck_Node) > Expr_Value_R (UB)); else -- fixed or discrete type Out_Of_Range := Expr_Value (Ck_Node) < Expr_Value (LB) or else Expr_Value (Ck_Node) > Expr_Value (UB); end if; -- Bounds of the type are static and the literal is -- out of range so make a warning message. if Out_Of_Range then if No (Warn_Node) then Add_Check (Compile_Time_Constraint_Error (Ck_Node, "static value out of range of}?", T_Typ)); else Add_Check (Compile_Time_Constraint_Error (Wnode, "static value out of range of}?", T_Typ)); end if; end if; else Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); end if; end; -- Here for the case of a non-static expression, we need a runtime -- check unless the source type range is guaranteed to be in the -- range of the target type. else if not In_Subrange_Of (S_Typ, T_Typ) then Cond := Discrete_Expr_Cond (Ck_Node, T_Typ); end if; end if; end if; if Is_Array_Type (T_Typ) and then Is_Array_Type (S_Typ) then if Is_Constrained (T_Typ) then Expr_Actual := Get_Referenced_Object (Ck_Node); Exptyp := Get_Actual_Subtype (Expr_Actual); if Is_Access_Type (Exptyp) then Exptyp := Designated_Type (Exptyp); end if; -- String_Literal case. This needs to be handled specially be- -- cause no index types are available for string literals. The -- condition is simply: -- T_Typ'Length = string-literal-length if Nkind (Expr_Actual) = N_String_Literal then null; -- General array case. Here we have a usable actual subtype for -- the expression, and the condition is built from the two types -- T_Typ'First < Exptyp'First or else -- T_Typ'Last > Exptyp'Last or else -- T_Typ'First(1) < Exptyp'First(1) or else -- T_Typ'Last(1) > Exptyp'Last(1) or else -- ... elsif Is_Constrained (Exptyp) then declare L_Index : Node_Id; R_Index : Node_Id; Ndims : Nat := Number_Dimensions (T_Typ); L_Low : Node_Id; L_High : Node_Id; R_Low : Node_Id; R_High : Node_Id; begin L_Index := First_Index (T_Typ); R_Index := First_Index (Exptyp); for Indx in 1 .. Ndims loop if not (Nkind (L_Index) = N_Raise_Constraint_Error or else Nkind (R_Index) = N_Raise_Constraint_Error) then Get_Index_Bounds (L_Index, L_Low, L_High); Get_Index_Bounds (R_Index, R_Low, R_High); -- Deal with compile time length check. Note that we -- skip this in the access case, because the access -- value may be null, so we cannot know statically. if not Subtypes_Statically_Match (Etype (L_Index), Etype (R_Index)) then -- If the target type is constrained then we -- have to check for exact equality of bounds -- (required for qualified expressions). if Is_Constrained (T_Typ) then Evolve_Or_Else (Cond, Range_Equal_E_Cond (Exptyp, T_Typ, Indx)); else Evolve_Or_Else (Cond, Range_E_Cond (Exptyp, T_Typ, Indx)); end if; end if; Next (L_Index); Next (R_Index); end if; end loop; end; -- Handle cases where we do not get a usable actual subtype that -- is constrained. This happens for example in the function call -- and explicit dereference cases. In these cases, we have to get -- the length or range from the expression itself, making sure we -- do not evaluate it more than once. -- Here Ck_Node is the original expression, or more properly the -- result of applying Duplicate_Expr to the original tree, -- forcing the result to be a name. else declare Ndims : Nat := Number_Dimensions (T_Typ); begin -- Build the condition for the explicit dereference case for Indx in 1 .. Ndims loop Evolve_Or_Else (Cond, Range_N_Cond (Ck_Node, T_Typ, Indx)); end loop; end; end if; else -- Generate an Action to check that the bounds of the -- source value are within the constraints imposed by the -- target type for a conversion to an unconstrained type. -- Rule is 4.6(38). if Nkind (Parent (Ck_Node)) = N_Type_Conversion then declare Opnd_Index : Node_Id; Targ_Index : Node_Id; begin Opnd_Index := First_Index (Get_Actual_Subtype (Ck_Node)); Targ_Index := First_Index (T_Typ); while Opnd_Index /= Empty loop if Nkind (Opnd_Index) = N_Range then if Is_In_Range (Low_Bound (Opnd_Index), Etype (Targ_Index)) and then Is_In_Range (High_Bound (Opnd_Index), Etype (Targ_Index)) then null; elsif Is_Out_Of_Range (Low_Bound (Opnd_Index), Etype (Targ_Index)) or else Is_Out_Of_Range (High_Bound (Opnd_Index), Etype (Targ_Index)) then Add_Check (Compile_Time_Constraint_Error (Wnode, "value out of range of}?", T_Typ)); else Evolve_Or_Else (Cond, Discrete_Range_Cond (Opnd_Index, Etype (Targ_Index))); end if; end if; Next_Index (Opnd_Index); Next_Index (Targ_Index); end loop; end; end if; end if; end if; -- Construct the test and insert into the tree if Present (Cond) then if Do_Access then Cond := Guard_Access (Cond, Loc, Ck_Node); end if; Add_Check (Make_Raise_Constraint_Error (Loc, Condition => Cond, Reason => CE_Range_Check_Failed)); end if; return Ret_Result; end Selected_Range_Checks; ------------------------------- -- Storage_Checks_Suppressed -- ------------------------------- function Storage_Checks_Suppressed (E : Entity_Id) return Boolean is begin return Scope_Suppress.Storage_Checks or else (Present (E) and then Suppress_Storage_Checks (E)); end Storage_Checks_Suppressed; --------------------------- -- Tag_Checks_Suppressed -- --------------------------- function Tag_Checks_Suppressed (E : Entity_Id) return Boolean is begin return Scope_Suppress.Tag_Checks or else (Present (E) and then Suppress_Tag_Checks (E)); end Tag_Checks_Suppressed; end Checks;