| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT COMPILER COMPONENTS -- |
| -- -- |
| -- E X P _ U T I L -- |
| -- -- |
| -- S p e c -- |
| -- -- |
| -- Copyright (C) 1992-2003 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. -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| -- Package containing utility procedures used throughout the expander |
| |
| with Exp_Tss; use Exp_Tss; |
| with Rtsfind; use Rtsfind; |
| with Sinfo; use Sinfo; |
| with Types; use Types; |
| |
| package Exp_Util is |
| |
| ----------------------------------------------- |
| -- Handling of Actions Associated with Nodes -- |
| ----------------------------------------------- |
| |
| -- The evaluation of certain expression nodes involves the elaboration |
| -- of associated types and other declarations, and the execution of |
| -- statement sequences. Expansion routines generating such actions must |
| -- find an appropriate place in the tree to hang the actions so that |
| -- they will be evaluated at the appropriate point. |
| |
| -- Some cases are simple: |
| |
| -- For an expression occurring in a simple statement that is in a list |
| -- of statements, the actions are simply inserted into the list before |
| -- the associated statement. |
| |
| -- For an expression occurring in a declaration (declarations always |
| -- appear in lists), the actions are similarly inserted into the list |
| -- just before the associated declaration. |
| |
| -- The following special cases arise: |
| |
| -- For actions associated with the right operand of a short circuit |
| -- form, the actions are first stored in the short circuit form node |
| -- in the Actions field. The expansion of these forms subsequently |
| -- expands the short circuit forms into if statements which can then |
| -- be moved as described above. |
| |
| -- For actions appearing in the Condition expression of a while loop, |
| -- or an elsif clause, the actions are similarly temporarily stored in |
| -- in the node (N_Elsif_Part or N_Iteration_Scheme) associated with |
| -- the expression using the Condition_Actions field. Subsequently, the |
| -- expansion of these nodes rewrites the control structures involved to |
| -- reposition the actions in normal statement sequence. |
| |
| -- For actions appearing in the then or else expression of a conditional |
| -- expression, these actions are similarly placed in the node, using the |
| -- Then_Actions or Else_Actions field as appropriate. Once again the |
| -- expansion of the N_Conditional_Expression node rewrites the node so |
| -- that the actions can be normally positioned. |
| |
| -- Basically what we do is to climb up to the tree looking for the |
| -- proper insertion point, as described by one of the above cases, |
| -- and then insert the appropriate action or actions. |
| |
| -- Note if more than one insert call is made specifying the same |
| -- Assoc_Node, then the actions are elaborated in the order of the |
| -- calls, and this guarantee is preserved for the special cases above. |
| |
| procedure Insert_Action |
| (Assoc_Node : Node_Id; |
| Ins_Action : Node_Id); |
| -- Insert the action Ins_Action at the appropriate point as described |
| -- above. The action is analyzed using the default checks after it is |
| -- inserted. Assoc_Node is the node with which the action is associated. |
| |
| procedure Insert_Action |
| (Assoc_Node : Node_Id; |
| Ins_Action : Node_Id; |
| Suppress : Check_Id); |
| -- Insert the action Ins_Action at the appropriate point as described |
| -- above. The action is analyzed using the default checks as modified |
| -- by the given Suppress argument after it is inserted. Assoc_Node is |
| -- the node with which the action is associated. |
| |
| procedure Insert_Actions |
| (Assoc_Node : Node_Id; |
| Ins_Actions : List_Id); |
| -- Insert the list of action Ins_Actions at the appropriate point as |
| -- described above. The actions are analyzed using the default checks |
| -- after they are inserted. Assoc_Node is the node with which the actions |
| -- are associated. Ins_Actions may be No_List, in which case the call has |
| -- no effect. |
| |
| procedure Insert_Actions |
| (Assoc_Node : Node_Id; |
| Ins_Actions : List_Id; |
| Suppress : Check_Id); |
| -- Insert the list of action Ins_Actions at the appropriate point as |
| -- described above. The actions are analyzed using the default checks |
| -- as modified by the given Suppress argument after they are inserted. |
| -- Assoc_Node is the node with which the actions are associated. |
| -- Ins_Actions may be No_List, in which case the call has no effect. |
| |
| procedure Insert_Actions_After |
| (Assoc_Node : Node_Id; |
| Ins_Actions : List_Id); |
| -- Assoc_Node must be a node in a list. Same as Insert_Actions but |
| -- actions will be inserted after N in a manner that is compatible with |
| -- the transient scope mechanism. This procedure must be used instead |
| -- of Insert_List_After if Assoc_Node may be in a transient scope. |
| -- |
| -- Implementation limitation: Assoc_Node must be a statement. We can |
| -- generalize to expressions if there is a need but this is tricky to |
| -- implement because of short-ciruits (among other things).??? |
| |
| procedure Insert_Library_Level_Action (N : Node_Id); |
| -- This procedure inserts and analyzes the node N as an action at the |
| -- library level for the current unit (i.e. it is attached to the |
| -- Actions field of the N_Compilation_Aux node for the main unit). |
| |
| procedure Insert_Library_Level_Actions (L : List_Id); |
| -- Similar, but inserts a list of actions. |
| |
| ----------------------- |
| -- Other Subprograms -- |
| ----------------------- |
| |
| procedure Adjust_Condition (N : Node_Id); |
| -- The node N is an expression whose root-type is Boolean, and which |
| -- represents a boolean value used as a condition (i.e. a True/False |
| -- value). This routine handles the case of C and Fortran convention |
| -- boolean types, which have zero/non-zero semantics rather than the |
| -- normal 0/1 semantics, and also the case of an enumeration rep |
| -- clause that specifies a non-standard representation. On return, |
| -- node N always has the type Standard.Boolean, with a value that |
| -- is a standard Boolean values of 0/1 for False/True. This procedure |
| -- is used in two situations. First, the processing for a condition |
| -- field always calls Adjust_Condition, so that the boolean value |
| -- presented to the backend is a standard value. Second, for the |
| -- code for boolean operations such as AND, Adjust_Condition is |
| -- called on both operands, and then the operation is done in the |
| -- domain of Standard_Boolean, then Adjust_Result_Type is called |
| -- on the result to possibly reset the original type. This procedure |
| -- also takes care of validity checking if Validity_Checks = Tests. |
| |
| procedure Adjust_Result_Type (N : Node_Id; T : Entity_Id); |
| -- The processing of boolean operations like AND uses the procedure |
| -- Adjust_Condition so that it can operate on Standard.Boolean, which |
| -- is the only boolean type on which the backend needs to be able to |
| -- implement such operators. This means that the result is also of |
| -- type Standard.Boolean. In general the type must be reset back to |
| -- the original type to get proper semantics, and that is the purpose |
| -- of this procedure. N is the node (of type Standard.Boolean), and |
| -- T is the desired type. As an optimization, this procedure leaves |
| -- the type as Standard.Boolean in contexts where this is permissible |
| -- (in particular for Condition fields, and for operands of other |
| -- logical operations higher up the tree). The call to this procedure |
| -- is completely ignored if the argument N is not of type Boolean. |
| |
| procedure Append_Freeze_Action (T : Entity_Id; N : Node_Id); |
| -- Add a new freeze action for the given type. The freeze action is |
| -- attached to the freeze node for the type. Actions will be elaborated |
| -- in the order in which they are added. Note that the added node is not |
| -- analyzed. The analyze call is found in Sem_Ch13.Expand_N_Freeze_Entity. |
| |
| procedure Append_Freeze_Actions (T : Entity_Id; L : List_Id); |
| -- Adds the given list of freeze actions (declarations or statements) |
| -- for the given type. The freeze actions are attached to the freeze |
| -- node for the type. Actions will be elaborated in the order in which |
| -- they are added, and the actions within the list will be elaborated in |
| -- list order. Note that the added nodes are not analyzed. The analyze |
| -- call is found in Sem_Ch13.Expand_N_Freeze_Entity. |
| |
| function Build_Runtime_Call (Loc : Source_Ptr; RE : RE_Id) return Node_Id; |
| -- Build an N_Procedure_Call_Statement calling the given runtime entity. |
| -- The call has no parameters. The first argument provides the location |
| -- information for the tree and for error messages. The call node is not |
| -- analyzed on return, the caller is responsible for analyzing it. |
| |
| function Build_Task_Image_Decls |
| (Loc : Source_Ptr; |
| Id_Ref : Node_Id; |
| A_Type : Entity_Id) |
| return List_Id; |
| -- Build declaration for a variable that holds an identifying string |
| -- to be used as a task name. Id_Ref is an identifier if the task is |
| -- a variable, and a selected or indexed component if the task is a |
| -- component of an object. If it is an indexed component, A_Type is |
| -- the corresponding array type. Its index types are used to build the |
| -- string as an image of the index values. For composite types, the |
| -- result includes two declarations: one for a generated function that |
| -- computes the image without using concatenation, and one for the |
| -- variable that holds the result. |
| |
| function Component_May_Be_Bit_Aligned (Comp : Entity_Id) return Boolean; |
| -- This function is in charge of detecting record components that may |
| -- cause trouble in the back end if an attempt is made to assign the |
| -- component. The back end can handle such assignments with no problem |
| -- if the components involved are small (64-bits or less) records or |
| -- scalar items (including bit-packed arrays represented with modular |
| -- types) or are both aligned on a byte boundary (starting on a byte |
| -- boundary, and occupying an integral number of bytes). |
| -- |
| -- However, problems arise for records larger than 64 bits, or for |
| -- arrays (other than bit-packed arrays represented with a modular |
| -- type) if the component starts on a non-byte boundary, or does |
| -- not occupy an integral number of bytes (i.e. there are some bits |
| -- possibly shared with fields at the start or beginning of the |
| -- component). The back end cannot handle loading and storing such |
| -- components in a single operation. |
| -- |
| -- This function is used to detect the troublesome situation. it is |
| -- conservative in the sense that it produces True unless it knows |
| -- for sure that the component is safe (as outlined in the first |
| -- paragraph above). The code generation for record and array |
| -- assignment checks for trouble using this function, and if so |
| -- the assignment is generated component-wise, which the back end |
| -- is required to handle correctly. |
| -- |
| -- Note that in GNAT 3, the back end will reject such components |
| -- anyway, so the hard work in checking for this case is wasted |
| -- in GNAT 3, but it's harmless, so it is easier to do it in |
| -- all cases, rather than conditionalize it in GNAT 5 or beyond. |
| |
| procedure Convert_To_Actual_Subtype (Exp : Node_Id); |
| -- The Etype of an expression is the nominal type of the expression, |
| -- not the actual subtype. Often these are the same, but not always. |
| -- For example, a reference to a formal of unconstrained type has the |
| -- unconstrained type as its Etype, but the actual subtype is obtained |
| -- by applying the actual bounds. This routine is given an expression, |
| -- Exp, and (if necessary), replaces it using Rewrite, with a conversion |
| -- to the actual subtype, building the actual subtype if necessary. If |
| -- the expression is already of the requested type, then it is unchanged. |
| |
| function Current_Sem_Unit_Declarations return List_Id; |
| -- Return the a place where it is fine to insert declarations for the |
| -- current semantic unit. If the unit is a package body, return the |
| -- visible declarations of the corresponding spec. For RCI stubs, this |
| -- is necessary because the point at which they are generated may not |
| -- be the earliest point at which they are used. |
| |
| function Duplicate_Subexpr |
| (Exp : Node_Id; |
| Name_Req : Boolean := False) |
| return Node_Id; |
| -- Given the node for a subexpression, this function makes a logical |
| -- copy of the subexpression, and returns it. This is intended for use |
| -- when the expansion of an expression needs to repeat part of it. For |
| -- example, replacing a**2 by a*a requires two references to a which |
| -- may be a complex subexpression. Duplicate_Subexpression guarantees |
| -- not to duplicate side effects. If necessary, it generates actions |
| -- to save the expression value in a temporary, inserting these actions |
| -- into the tree using Insert_Actions with Exp as the insertion location. |
| -- The original expression and the returned result then become references |
| -- to this saved value. Exp must be analyzed on entry. On return, Exp |
| -- is analyzed, but the caller is responsible for analyzing the returned |
| -- copy after it is attached to the tree. The Name_Req flag is set to |
| -- ensure that the result is suitable for use in a context requiring a |
| -- name (e.g. the prefix of an attribute reference). |
| -- |
| -- Note that if there are any run time checks in Exp, these same checks |
| -- will be duplicated in the returned duplicated expression. The two |
| -- following functions allow this behavior to be modified. |
| |
| function Duplicate_Subexpr_No_Checks |
| (Exp : Node_Id; |
| Name_Req : Boolean := False) |
| return Node_Id; |
| -- Identical in effect to Duplicate_Subexpr, except that Remove_Checks |
| -- is called on the result, so that the duplicated expression does not |
| -- include checks. This is appropriate for use when Exp, the original |
| -- expression is unconditionally elaborated before the duplicated |
| -- expression, so that there is no need to repeat any checks. |
| |
| function Duplicate_Subexpr_Move_Checks |
| (Exp : Node_Id; |
| Name_Req : Boolean := False) |
| return Node_Id; |
| -- Identical in effect to Duplicate_Subexpr, except that Remove_Checks |
| -- is called on Exp after the duplication is complete, so that the |
| -- original expression does not include checks. In this case the result |
| -- returned (the duplicated expression) will retain the original checks. |
| -- This is appropriate for use when the duplicated expression is sure |
| -- to be elaborated before the original expression Exp, so that there |
| -- is no need to repeat the checks. |
| |
| procedure Ensure_Defined (Typ : Entity_Id; N : Node_Id); |
| -- This procedure ensures that type referenced by Typ is defined. For the |
| -- case of a type other than an Itype, nothing needs to be done, since |
| -- all such types have declaration nodes. For Itypes, an N_Itype_Reference |
| -- node is generated and inserted at the given node N. This is typically |
| -- used to ensure that an Itype is properly defined outside a conditional |
| -- construct when it is referenced in more than one branch. |
| |
| procedure Evolve_And_Then (Cond : in out Node_Id; Cond1 : Node_Id); |
| -- Rewrites Cond with the expression: Cond and then Cond1. If Cond is |
| -- Empty, then simply returns Cond1 (this allows the use of Empty to |
| -- initialize a series of checks evolved by this routine, with a final |
| -- result of Empty indicating that no checks were required). The Sloc |
| -- field of the constructed N_And_Then node is copied from Cond1. |
| |
| procedure Evolve_Or_Else (Cond : in out Node_Id; Cond1 : Node_Id); |
| -- Rewrites Cond with the expression: Cond or else Cond1. If Cond is |
| -- Empty, then simply returns Cond1 (this allows the use of Empty to |
| -- initialize a series of checks evolved by this routine, with a final |
| -- result of Empty indicating that no checks were required). The Sloc |
| -- field of the constructed N_And_Then node is copied from Cond1. |
| |
| procedure Expand_Subtype_From_Expr |
| (N : Node_Id; |
| Unc_Type : Entity_Id; |
| Subtype_Indic : Node_Id; |
| Exp : Node_Id); |
| -- Build a constrained subtype from the initial value in object |
| -- declarations and/or allocations when the type is indefinite (including |
| -- class-wide). |
| |
| function Find_Prim_Op (T : Entity_Id; Name : Name_Id) return Entity_Id; |
| -- Find the first primitive operation of type T whose name is 'Name'. |
| -- This function allows the use of a primitive operation which is not |
| -- directly visible. If T is a class wide type, then the reference is |
| -- to an operation of the corresponding root type. |
| |
| function Find_Prim_Op |
| (T : Entity_Id; |
| Name : TSS_Name_Type) return Entity_Id; |
| -- Find the first primitive operation of type T whose name has the form |
| -- indicated by the name parameter (i.e. is a type support subprogram |
| -- with the indicated suffix). This function allows use of a primitive |
| -- operation which is not directly visible. If T is a class wide type, |
| -- then the reference is to an operation of the corresponding root type. |
| |
| procedure Force_Evaluation |
| (Exp : Node_Id; |
| Name_Req : Boolean := False); |
| -- Force the evaluation of the expression right away. Similar behavior |
| -- to Remove_Side_Effects when Variable_Ref is set to TRUE. That is to |
| -- say, it removes the side-effects and capture the values of the |
| -- variables. Remove_Side_effects guarantees that multiple evaluations |
| -- of the same expression won't generate multiple side effects, whereas |
| -- Force_Evaluation further guarantees that all evaluations will yield |
| -- the same result. |
| |
| procedure Generate_Poll_Call (N : Node_Id); |
| -- If polling is active, then a call to the Poll routine is built, |
| -- and then inserted before the given node N and analyzed. |
| |
| procedure Get_Current_Value_Condition |
| (Var : Node_Id; |
| Op : out Node_Kind; |
| Val : out Node_Id); |
| -- This routine processes the Current_Value field of the variable Var. |
| -- If the Current_Value field is null or if it represents a known value, |
| -- then on return Cond is set to N_Empty, and Val is set to Empty. |
| -- |
| -- The other case is when Current_Value points to an N_If_Statement |
| -- or an N_Elsif_Part (while statement). Such a setting only occurs |
| -- if the condition of an IF or ELSIF is of the form X op Y, where X |
| -- is the variable in question, Y is a compile-time known value, and |
| -- op is one of the six possible relational operators. |
| -- |
| -- In this case, Get_Current_Condition digs out the condition, and |
| -- then checks if the condition is known false, known true, or not |
| -- known at all. In the first two cases, Get_Current_Condition will |
| -- return with Op set to the appropriate conditional operator (inverted |
| -- if the condition is known false), and Val set to the constant value. |
| -- If the condition is not known, then Cond and Val are set for the |
| -- empty case (N_Empty and Empty). |
| -- |
| -- The check for whether the condition is true/false unknown depends |
| -- on the case: |
| -- |
| -- For an IF, the condition is known true in the THEN part, known |
| -- false in any ELSIF or ELSE part, and not known outside the IF |
| -- statement in question. |
| -- |
| -- For an ELSIF, the condition is known true in the ELSIF part, |
| -- known FALSE in any subsequent ELSIF, or ELSE part, and not |
| -- known before the ELSIF, or after the end of the IF statement. |
| -- |
| -- The caller can use this result to determine the value (for the |
| -- case of N_Op_Eq), or to determine the result of some other test |
| -- in other cases (e.g. no access check required if N_Op_Ne Null). |
| |
| function Homonym_Number (Subp : Entity_Id) return Nat; |
| -- Here subp is the entity for a subprogram. This routine returns the |
| -- homonym number used to disambiguate overloaded subprograms in the |
| -- same scope (the number is used as part of constructed names to make |
| -- sure that they are unique). The number is the ordinal position on |
| -- the Homonym chain, counting only entries in the curren scope. If |
| -- an entity is not overloaded, the returned number will be one. |
| |
| function Inside_Init_Proc return Boolean; |
| -- Returns True if current scope is within an init proc |
| |
| function In_Unconditional_Context (Node : Node_Id) return Boolean; |
| -- Node is the node for a statement or a component of a statement. |
| -- This function deteermines if the statement appears in a context |
| -- that is unconditionally executed, i.e. it is not within a loop |
| -- or a conditional or a case statement etc. |
| |
| function Is_All_Null_Statements (L : List_Id) return Boolean; |
| -- Return True if all the items of the list are N_Null_Statement |
| -- nodes. False otherwise. True for an empty list. It is an error |
| -- to call this routine with No_List as the argument. |
| |
| function Is_Ref_To_Bit_Packed_Array (P : Node_Id) return Boolean; |
| -- Determine whether the node P is a reference to a bit packed |
| -- array, i.e. whether the designated object is a component of |
| -- a bit packed array, or a subcomponent of such a component. |
| -- If so, then all subscripts in P are evaluated with a call |
| -- to Force_Evaluation, and True is returned. Otherwise False |
| -- is returned, and P is not affected. |
| |
| function Is_Ref_To_Bit_Packed_Slice (P : Node_Id) return Boolean; |
| -- Determine whether the node P is a reference to a bit packed |
| -- slice, i.e. whether the designated object is bit packed slice |
| -- or a component of a bit packed slice. Return True if so. |
| |
| function Is_Possibly_Unaligned_Slice (P : Node_Id) return Boolean; |
| -- Determine whether the node P is a slice of an array where the slice |
| -- result may cause alignment problems because it has an alignment that |
| -- is not compatible with the type. Return True if so. |
| |
| function Is_Possibly_Unaligned_Object (P : Node_Id) return Boolean; |
| -- Node P is an object reference. This function returns True if it |
| -- is possible that the object may not be aligned according to the |
| -- normal default alignment requirement for its type (e.g. if it |
| -- appears in a packed record, or as part of a component that has |
| -- a component clause. |
| |
| function Is_Renamed_Object (N : Node_Id) return Boolean; |
| -- Returns True if the node N is a renamed object. An expression |
| -- is considered to be a renamed object if either it is the Name |
| -- of an object renaming declaration, or is the prefix of a name |
| -- which is a renamed object. For example, in: |
| -- |
| -- x : r renames a (1 .. 2) (1); |
| -- |
| -- We consider that a (1 .. 2) is a renamed object since it is the |
| -- prefix of the name in the renaming declaration. |
| |
| function Is_Untagged_Derivation (T : Entity_Id) return Boolean; |
| -- Returns true if type T is not tagged and is a derived type, |
| -- or is a private type whose completion is such a type. |
| |
| procedure Kill_Dead_Code (N : Node_Id); |
| -- N represents a node for a section of code that is known to be |
| -- dead. The node is deleted, and any exception handler references |
| -- and warning messages relating to this code are removed. |
| |
| procedure Kill_Dead_Code (L : List_Id); |
| -- Like the above procedure, but applies to every element in the given |
| -- list. Each of the entries is removed from the list before killing it. |
| |
| function Known_Non_Negative (Opnd : Node_Id) return Boolean; |
| -- Given a node for a subexpression, determines if it represents a value |
| -- that cannot possibly be negative, and if so returns True. A value of |
| -- False means that it is not known if the value is positive or negative. |
| |
| function Known_Non_Null (N : Node_Id) return Boolean; |
| -- Given a node N for a subexpression of an access type, determines if |
| -- this subexpression yields a value that is known at compile time to |
| -- be non-null and returns True if so. Returns False otherwise. It is |
| -- an error to call this function if N is not of an access type. |
| |
| function Make_Subtype_From_Expr |
| (E : Node_Id; |
| Unc_Typ : Entity_Id) |
| return Node_Id; |
| -- Returns a subtype indication corresponding to the actual type of an |
| -- expression E. Unc_Typ is an unconstrained array or record, or |
| -- a classwide type. |
| |
| function May_Generate_Large_Temp (Typ : Entity_Id) return Boolean; |
| -- Determines if the given type, Typ, may require a large temporary |
| -- of the type that causes trouble if stack checking is enabled. The |
| -- result is True only if stack checking is enabled and the size of |
| -- the type is known at compile time and large, where large is defined |
| -- hueristically by the body of this routine. The purpose of this |
| -- routine is to help avoid generating troublesome temporaries that |
| -- intefere with the stack checking mechanism. |
| |
| procedure Remove_Side_Effects |
| (Exp : Node_Id; |
| Name_Req : Boolean := False; |
| Variable_Ref : Boolean := False); |
| -- Given the node for a subexpression, this function replaces the node |
| -- if necessary by an equivalent subexpression that is guaranteed to be |
| -- side effect free. This is done by extracting any actions that could |
| -- cause side effects, and inserting them using Insert_Actions into the |
| -- tree to which Exp is attached. Exp must be analayzed and resolved |
| -- before the call and is analyzed and resolved on return. The Name_Req |
| -- may only be set to True if Exp has the form of a name, and the |
| -- effect is to guarantee that any replacement maintains the form of a |
| -- name. If Variable_Ref is set to TRUE, a variable is considered as a |
| -- side effect (used in implementing Force_Evaluation). Note: after a |
| -- call to Remove_Side_Effects, it is safe to use a call to |
| -- New_Copy_Tree to obtain a copy of the resulting expression. |
| |
| function Safe_Unchecked_Type_Conversion (Exp : Node_Id) return Boolean; |
| -- Given the node for an N_Unchecked_Type_Conversion, return True |
| -- if this is an unchecked conversion that Gigi can handle directly. |
| -- Otherwise return False if it is one for which the front end must |
| -- provide a temporary. Note that the node need not be analyzed, and |
| -- thus the Etype field may not be set, but in that case it must be |
| -- the case that the Subtype_Mark field of the node is set/analyzed. |
| |
| procedure Set_Elaboration_Flag (N : Node_Id; Spec_Id : Entity_Id); |
| -- N is the node for a subprogram or generic body, and Spec_Id |
| -- is the entity for the corresponding spec. If an elaboration |
| -- entity is defined, then this procedure generates an assignment |
| -- statement to set it True, immediately after the body is elaborated. |
| -- However, no assignment is generated in the case of library level |
| -- procedures, since the setting of the flag in this case is generated |
| -- in the binder. We do that so that we can detect cases where this is |
| -- the only elaboration action that is required. |
| |
| function Target_Has_Fixed_Ops |
| (Left_Typ : Entity_Id; |
| Right_Typ : Entity_Id; |
| Result_Typ : Entity_Id) |
| return Boolean; |
| -- Returns True if and only if the target machine has direct support |
| -- for fixed-by-fixed multiplications and divisions for the given |
| -- operand and result types. This is called in package Exp_Fixd to |
| -- determine whether to expand such operations. |
| |
| function Type_May_Have_Bit_Aligned_Components |
| (Typ : Entity_Id) return Boolean; |
| -- Determines if Typ is a composite type that has within it (looking |
| -- down recursively at any subcomponents), a record type which has a |
| -- component that may be bit aligned (see Possible_Bit_Aligned_Component). |
| -- The result is conservative, in that a result of False is decisive. |
| -- A result of True means that such a component may or may not be present. |
| |
| procedure Wrap_Cleanup_Procedure (N : Node_Id); |
| -- Given an N_Subprogram_Body node, this procedure adds an Abort_Defer |
| -- call at the start of the statement sequence, and an Abort_Undefer call |
| -- at the end of the statement sequence. All cleanup routines (i.e. those |
| -- that are called from "at end" handlers) must defer abort on entry and |
| -- undefer abort on exit. Note that it is assumed that the code for the |
| -- procedure does not contain any return statements which would allow the |
| -- flow of control to escape doing the undefer call. |
| |
| private |
| pragma Inline (Force_Evaluation); |
| pragma Inline (Duplicate_Subexpr); |
| |
| end Exp_Util; |
