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diff --git a/gcc-4.4.0/gcc/ada/exp_util.ads b/gcc-4.4.0/gcc/ada/exp_util.ads new file mode 100644 index 000000000..5848d5d71 --- /dev/null +++ b/gcc-4.4.0/gcc/ada/exp_util.ads @@ -0,0 +1,674 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- E X P _ U T I L -- +-- -- +-- S p e c -- +-- -- +-- Copyright (C) 1992-2008, Free Software Foundation, Inc. -- +-- -- +-- GNAT is free software; you can redistribute it and/or modify it under -- +-- terms of the GNU General Public License as published by the Free Soft- -- +-- ware Foundation; either version 3, or (at your option) any later ver- -- +-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- +-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- +-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- +-- for more details. You should have received a copy of the GNU General -- +-- Public License distributed with GNAT; see file COPYING3. If not, go to -- +-- http://www.gnu.org/licenses for a complete copy of the license. -- +-- -- +-- GNAT was originally developed by the GNAT team at New York University. -- +-- Extensive contributions were provided by Ada Core Technologies Inc. -- +-- -- +------------------------------------------------------------------------------ + +-- Package containing utility procedures used throughout the expander + +with Exp_Tss; use Exp_Tss; +with Namet; use Namet; +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-circuits (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 Exp_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 + -- Exp_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; + In_Init_Proc : Boolean := False) 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 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. + -- + -- If In_Init_Proc is true, the call is part of the initialization of + -- a component of a composite type, and the enclosing initialization + -- procedure must be flagged as using the secondary stack. If In_Init_Proc + -- is false, the call is for a stand-alone object, and the generated + -- function itself must do its own cleanups. + + 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 is 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 Corresponding_Runtime_Package (Typ : Entity_Id) return RTU_Id; + -- Return the id of the runtime package that will provide support for + -- concurrent type Typ. Currently only protected types are supported, + -- and the returned value is one of the following: + -- System_Tasking_Protected_Objects + -- System_Tasking_Protected_Objects_Entries + -- System_Tasking_Protected_Objects_Single_Entry + + function Current_Sem_Unit_Declarations return List_Id; + -- Return the 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_Subexpr 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 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. + + function Entry_Names_OK return Boolean; + -- Determine whether it is appropriate to dynamically allocate strings + -- which represent entry [family member] names. These strings are created + -- by the compiler and used by GDB. + + 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_Or_Else 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_Interface_ADT + (T : Entity_Id; + Iface : Entity_Id) return Elmt_Id; + -- Ada 2005 (AI-251): Given a type T implementing the interface Iface, + -- return the element of Access_Disp_Table containing the tag of the + -- interface. + + function Find_Interface_Tag + (T : Entity_Id; + Iface : Entity_Id) return Entity_Id; + -- Ada 2005 (AI-251): Given a type T implementing the interface Iface, + -- return the record component containing the tag of Iface. + + 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. Raises Program_Error + -- exception if no primitive operation is found. This is normally an + -- internal error, but in some cases is an expected consequence of + -- illegalities elsewhere. + + 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. + -- Raises Program_Error exception if no primitive operation is found. + -- This is normally an internal error, but in some cases is an expected + -- consequence of illegalities elsewhere. + + function Find_Protection_Object (Scop : Entity_Id) return Entity_Id; + -- Traverse the scope stack starting from Scop and look for an entry, + -- entry family, or a subprogram that has a Protection_Object and return + -- it. Raises Program_Error if no such entity is found since the context + -- in which this routine is invoked should always have a protection + -- object. + + 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 captures 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 or a N_Iteration_Scheme node (see description in Einfo for + -- exact details). 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 Op 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 Has_Controlled_Coextensions (Typ : Entity_Id) return Boolean; + -- Determine whether a record type has anonymous access discriminants with + -- a controlled designated type. + + 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 current 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 determines 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_Library_Level_Tagged_Type (Typ : Entity_Id) return Boolean; + -- Return True if Typ is a library level tagged type. Currently we use + -- this information to build statically allocated dispatch tables. + + function Is_Ref_To_Bit_Packed_Array (N : 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 (N : 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 (N : 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 (N : Node_Id) return Boolean; + -- Node N 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. + + function Is_Volatile_Reference (N : Node_Id) return Boolean; + -- Checks if the node N represents a volatile reference, which can be + -- either a direct reference to a variable treated as volatile, or an + -- indexed/selected component where the prefix is treated as volatile, + -- or has Volatile_Components set. A slice of a volatile variable is + -- also volatile. + + procedure Kill_Dead_Code (N : Node_Id; Warn : Boolean := False); + -- N represents a node for a section of code that is known to be dead. Any + -- exception handler references and warning messages relating to this code + -- are removed. If Warn is True, a warning will be output at the start of N + -- indicating the deletion of the code. Note that the tree for the deleted + -- code is left intact so that e.g. cross-reference data is still valid. + + procedure Kill_Dead_Code (L : List_Id; Warn : Boolean := False); + -- Like the above procedure, but applies to every element in the given + -- list. If Warn is True, a warning will be output at the start of N + -- indicating the deletion of the code. + + 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 Known_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 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 + -- kind that causes back-end trouble if stack checking is enabled. The + -- result is True only the size of the type is known at compile time and + -- large, where large is defined heuristically by the body of this routine. + -- The purpose of this routine is to help avoid generating troublesome + -- temporaries that interfere with stack checking mechanism. Note that the + -- caller has to check whether stack checking is actually enabled in order + -- to guide the expansion (typically of a function call). + + function Non_Limited_Designated_Type (T : Entity_Id) return Entity_Id; + -- An anonymous access type may designate a limited view. Check whether + -- non-limited view is available during expansion, to examine components + -- or other characteristics of the full type. + + function OK_To_Do_Constant_Replacement (E : Entity_Id) return Boolean; + -- This function is used when testing whether or not to replace a reference + -- to entity E by a known constant value. Such replacement must be done + -- only in a scope known to be safe for such replacements. In particular, + -- if we are within a subprogram and the entity E is declared outside the + -- subprogram then we cannot do the replacement, since we do not attempt to + -- trace subprogram call flow. It is also unsafe to replace statically + -- allocated values (since they can be modified outside the scope), and we + -- also inhibit replacement of Volatile or aliased objects since their + -- address might be captured in a way we do not detect. A value of True is + -- returned only if the replacement is safe. + + function Possible_Bit_Aligned_Component (N : Node_Id) return Boolean; + -- This function is used during processing the assignment of a record or + -- indexed component. The argument N is either the left hand or right hand + -- side of an assignment, and this function determines if there is a record + -- component reference where the record may be bit aligned in a manner that + -- causes trouble for the back end (see Component_May_Be_Bit_Aligned for + -- further details). + + 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 analyzed 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 name. If Variable_Ref is set to + -- TRUE, a variable is considered as side effect (used in implementing + -- Force_Evaluation). Note: after call to Remove_Side_Effects, it is safe + -- to call New_Copy_Tree to obtain a copy of the resulting expression. + + function Represented_As_Scalar (T : Entity_Id) return Boolean; + -- Returns True iff the implementation of this type in code generation + -- terms is scalar. This is true for scalars in the Ada sense, and for + -- packed arrays which are represented by a scalar (modular) type. + + 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_Current_Value_Condition (Cnode : Node_Id); + -- Cnode is N_If_Statement, N_Elsif_Part, or N_Iteration_Scheme (the latter + -- when a WHILE condition is present). This call checks whether Condition + -- (Cnode) has embedded expressions of a form that should result in setting + -- the Current_Value field of one or more entities, and if so sets these + -- fields to point to Cnode. + + 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. + + procedure Set_Renamed_Subprogram (N : Node_Id; E : Entity_Id); + -- N is an node which is an entity name that represents the name of a + -- renamed subprogram. The node is rewritten to be an identifier that + -- refers directly to the renamed subprogram, given by entity E. + + procedure Silly_Boolean_Array_Not_Test (N : Node_Id; T : Entity_Id); + -- N is the node for a boolean array NOT operation, and T is the type of + -- the array. This routine deals with the silly case where the subtype of + -- the boolean array is False..False or True..True, where it is required + -- that a Constraint_Error exception be raised (RM 4.5.6(6)). + + procedure Silly_Boolean_Array_Xor_Test (N : Node_Id; T : Entity_Id); + -- N is the node for a boolean array XOR operation, and T is the type of + -- the array. This routine deals with the silly case where the subtype of + -- the boolean array is True..True, where a raise of a Constraint_Error + -- exception is required (RM 4.5.6(6)). + + 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 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 (Duplicate_Subexpr); + pragma Inline (Force_Evaluation); + pragma Inline (Is_Library_Level_Tagged_Type); +end Exp_Util; |