diff options
Diffstat (limited to 'gcc/ada/sem_ch8.adb')
| -rw-r--r-- | gcc/ada/sem_ch8.adb | 5224 |
1 files changed, 5224 insertions, 0 deletions
diff --git a/gcc/ada/sem_ch8.adb b/gcc/ada/sem_ch8.adb new file mode 100644 index 00000000000..ab90a102d70 --- /dev/null +++ b/gcc/ada/sem_ch8.adb @@ -0,0 +1,5224 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- S E M . C H 8 -- +-- -- +-- B o d y -- +-- -- +-- $Revision: 1.583 $ +-- -- +-- Copyright (C) 1992-2001, 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. -- +-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). -- +-- -- +------------------------------------------------------------------------------ + +with Atree; use Atree; +with Debug; use Debug; +with Einfo; use Einfo; +with Elists; use Elists; +with Errout; use Errout; +with Exp_Util; use Exp_Util; +with Fname; use Fname; +with Freeze; use Freeze; +with Lib; use Lib; +with Lib.Load; use Lib.Load; +with Lib.Xref; use Lib.Xref; +with Namet; use Namet; +with Nlists; use Nlists; +with Nmake; use Nmake; +with Opt; use Opt; +with Output; use Output; +with Restrict; use Restrict; +with Rtsfind; use Rtsfind; +with Sem; use Sem; +with Sem_Ch3; use Sem_Ch3; +with Sem_Ch4; use Sem_Ch4; +with Sem_Ch6; use Sem_Ch6; +with Sem_Ch12; use Sem_Ch12; +with Sem_Res; use Sem_Res; +with Sem_Util; use Sem_Util; +with Sem_Type; use Sem_Type; +with Stand; use Stand; +with Sinfo; use Sinfo; +with Sinfo.CN; use Sinfo.CN; +with Snames; use Snames; +with Style; use Style; +with Table; +with Tbuild; use Tbuild; +with Uintp; use Uintp; + +with GNAT.Spelling_Checker; use GNAT.Spelling_Checker; + +package body Sem_Ch8 is + + ------------------------------------ + -- Visibility and Name Resolution -- + ------------------------------------ + + -- This package handles name resolution and the collection of + -- interpretations for overloaded names, prior to overload resolution. + + -- Name resolution is the process that establishes a mapping between source + -- identifiers and the entities they denote at each point in the program. + -- Each entity is represented by a defining occurrence. Each identifier + -- that denotes an entity points to the corresponding defining occurrence. + -- This is the entity of the applied occurrence. Each occurrence holds + -- an index into the names table, where source identifiers are stored. + + -- Each entry in the names table for an identifier or designator uses the + -- Info pointer to hold a link to the currently visible entity that has + -- this name (see subprograms Get_Name_Entity_Id and Set_Name_Entity_Id + -- in package Sem_Util). The visibility is initialized at the beginning of + -- semantic processing to make entities in package Standard immediately + -- visible. The visibility table is used in a more subtle way when + -- compiling subunits (see below). + + -- Entities that have the same name (i.e. homonyms) are chained. In the + -- case of overloaded entities, this chain holds all the possible meanings + -- of a given identifier. The process of overload resolution uses type + -- information to select from this chain the unique meaning of a given + -- identifier. + + -- Entities are also chained in their scope, through the Next_Entity link. + -- As a consequence, the name space is organized as a sparse matrix, where + -- each row corresponds to a scope, and each column to a source identifier. + -- Open scopes, that is to say scopes currently being compiled, have their + -- corresponding rows of entities in order, innermost scope first. + + -- The scopes of packages that are mentioned in context clauses appear in + -- no particular order, interspersed among open scopes. This is because + -- in the course of analyzing the context of a compilation, a package + -- declaration is first an open scope, and subsequently an element of the + -- context. If subunits or child units are present, a parent unit may + -- appear under various guises at various times in the compilation. + + -- When the compilation of the innermost scope is complete, the entities + -- defined therein are no longer visible. If the scope is not a package + -- declaration, these entities are never visible subsequently, and can be + -- removed from visibility chains. If the scope is a package declaration, + -- its visible declarations may still be accessible. Therefore the entities + -- defined in such a scope are left on the visibility chains, and only + -- their visibility (immediately visibility or potential use-visibility) + -- is affected. + + -- The ordering of homonyms on their chain does not necessarily follow + -- the order of their corresponding scopes on the scope stack. For + -- example, if package P and the enclosing scope both contain entities + -- named E, then when compiling the package body the chain for E will + -- hold the global entity first, and the local one (corresponding to + -- the current inner scope) next. As a result, name resolution routines + -- do not assume any relative ordering of the homonym chains, either + -- for scope nesting or to order of appearance of context clauses. + + -- When compiling a child unit, entities in the parent scope are always + -- immediately visible. When compiling the body of a child unit, private + -- entities in the parent must also be made immediately visible. There + -- are separate routines to make the visible and private declarations + -- visible at various times (see package Sem_Ch7). + + -- +--------+ +-----+ + -- | In use |-------->| EU1 |--------------------------> + -- +--------+ +-----+ + -- | | + -- +--------+ +-----+ +-----+ + -- | Stand. |---------------->| ES1 |--------------->| ES2 |---> + -- +--------+ +-----+ +-----+ + -- | | + -- +---------+ | +-----+ + -- | with'ed |------------------------------>| EW2 |---> + -- +---------+ | +-----+ + -- | | + -- +--------+ +-----+ +-----+ + -- | Scope2 |---------------->| E12 |--------------->| E22 |---> + -- +--------+ +-----+ +-----+ + -- | | + -- +--------+ +-----+ +-----+ + -- | Scope1 |---------------->| E11 |--------------->| E12 |---> + -- +--------+ +-----+ +-----+ + -- ^ | | + -- | | | + -- | +---------+ | | + -- | | with'ed |-----------------------------------------> + -- | +---------+ | | + -- | | | + -- Scope stack | | + -- (innermost first) | | + -- +----------------------------+ + -- Names table => | Id1 | | | | Id2 | + -- +----------------------------+ + + -- Name resolution must deal with several syntactic forms: simple names, + -- qualified names, indexed names, and various forms of calls. + + -- Each identifier points to an entry in the names table. The resolution + -- of a simple name consists in traversing the homonym chain, starting + -- from the names table. If an entry is immediately visible, it is the one + -- designated by the identifier. If only potemtially use-visible entities + -- are on the chain, we must verify that they do not hide each other. If + -- the entity we find is overloadable, we collect all other overloadable + -- entities on the chain as long as they are not hidden. + -- + -- To resolve expanded names, we must find the entity at the intersection + -- of the entity chain for the scope (the prefix) and the homonym chain + -- for the selector. In general, homonym chains will be much shorter than + -- entity chains, so it is preferable to start from the names table as + -- well. If the entity found is overloadable, we must collect all other + -- interpretations that are defined in the scope denoted by the prefix. + + -- For records, protected types, and tasks, their local entities are + -- removed from visibility chains on exit from the corresponding scope. + -- From the outside, these entities are always accessed by selected + -- notation, and the entity chain for the record type, protected type, + -- etc. is traversed sequentially in order to find the designated entity. + + -- The discriminants of a type and the operations of a protected type or + -- task are unchained on exit from the first view of the type, (such as + -- a private or incomplete type declaration, or a protected type speci- + -- fication) and rechained when compiling the second view. + + -- In the case of operators, we do not make operators on derived types + -- explicit. As a result, the notation P."+" may denote either a user- + -- defined function with name "+", or else an implicit declaration of the + -- operator "+" in package P. The resolution of expanded names always + -- tries to resolve an operator name as such an implicitly defined entity, + -- in addition to looking for explicit declarations. + + -- All forms of names that denote entities (simple names, expanded names, + -- character literals in some cases) have a Entity attribute, which + -- identifies the entity denoted by the name. + + --------------------- + -- The Scope Stack -- + --------------------- + + -- The Scope stack keeps track of the scopes currently been compiled. + -- Every entity that contains declarations (including records) is placed + -- on the scope stack while it is being processed, and removed at the end. + -- Whenever a non-package scope is exited, the entities defined therein + -- are removed from the visibility table, so that entities in outer scopes + -- become visible (see previous description). On entry to Sem, the scope + -- stack only contains the package Standard. As usual, subunits complicate + -- this picture ever so slightly. + + -- The Rtsfind mechanism can force a call to Semantics while another + -- compilation is in progress. The unit retrieved by Rtsfind must be + -- compiled in its own context, and has no access to the visibility of + -- the unit currently being compiled. The procedures Save_Scope_Stack and + -- Restore_Scope_Stack make entities in current open scopes invisible + -- before compiling the retrieved unit, and restore the compilation + -- environment afterwards. + + ------------------------ + -- Compiling subunits -- + ------------------------ + + -- Subunits must be compiled in the environment of the corresponding + -- stub, that is to say with the same visibility into the parent (and its + -- context) that is available at the point of the stub declaration, but + -- with the additional visibility provided by the context clause of the + -- subunit itself. As a result, compilation of a subunit forces compilation + -- of the parent (see description in lib-). At the point of the stub + -- declaration, Analyze is called recursively to compile the proper body + -- of the subunit, but without reinitializing the names table, nor the + -- scope stack (i.e. standard is not pushed on the stack). In this fashion + -- the context of the subunit is added to the context of the parent, and + -- the subunit is compiled in the correct environment. Note that in the + -- course of processing the context of a subunit, Standard will appear + -- twice on the scope stack: once for the parent of the subunit, and + -- once for the unit in the context clause being compiled. However, the + -- two sets of entities are not linked by homonym chains, so that the + -- compilation of any context unit happens in a fresh visibility + -- environment. + + ------------------------------- + -- Processing of USE Clauses -- + ------------------------------- + + -- Every defining occurrence has a flag indicating if it is potentially use + -- visible. Resolution of simple names examines this flag. The processing + -- of use clauses consists in setting this flag on all visible entities + -- defined in the corresponding package. On exit from the scope of the use + -- clause, the corresponding flag must be reset. However, a package may + -- appear in several nested use clauses (pathological but legal, alas!) + -- which forces us to use a slightly more involved scheme: + + -- a) The defining occurrence for a package holds a flag -In_Use- to + -- indicate that it is currently in the scope of a use clause. If a + -- redundant use clause is encountered, then the corresponding occurence + -- of the package name is flagged -Redundant_Use-. + + -- b) On exit from a scope, the use clauses in its declarative part are + -- scanned. The visibility flag is reset in all entities declared in + -- package named in a use clause, as long as the package is not flagged + -- as being in a redundant use clause (in which case the outer use + -- clause is still in effect, and the direct visibility of its entities + -- must be retained). + + -- Note that entities are not removed from their homonym chains on exit + -- from the package specification. A subsequent use clause does not need + -- to rechain the visible entities, but only to establish their direct + -- visibility. + + ----------------------------------- + -- Handling private declarations -- + ----------------------------------- + + -- The principle that each entity has a single defining occurrence clashes + -- with the presence of two separate definitions for private types: the + -- first is the private type declaration, and second is the full type + -- declaration. It is important that all references to the type point to + -- the same defining occurence, namely the first one. To enforce the two + -- separate views of the entity, the corresponding information is swapped + -- between the two declarations. Outside of the package, the defining + -- occurence only contains the private declaration information, while in + -- the private part and the body of the package the defining occurrence + -- contains the full declaration. To simplify the swap, the defining + -- occurrence that currently holds the private declaration points to the + -- full declaration. During semantic processing the defining occurence + -- also points to a list of private dependents, that is to say access + -- types or composite types whose designated types or component types are + -- subtypes or derived types of the private type in question. After the + -- full declaration has been seen, the private dependents are updated to + -- indicate that they have full definitions. + + ------------------------------------ + -- Handling of Undefined Messages -- + ------------------------------------ + + -- In normal mode, only the first use of an undefined identifier generates + -- a message. The table Urefs is used to record error messages that have + -- been issued so that second and subsequent ones do not generate further + -- messages. However, the second reference causes text to be added to the + -- original undefined message noting "(more references follow)". The + -- full error list option (-gnatf) forces messages to be generated for + -- every reference and disconnects the use of this table. + + type Uref_Entry is record + Node : Node_Id; + -- Node for identifier for which original message was posted. The + -- Chars field of this identifier is used to detect later references + -- to the same identifier. + + Err : Error_Msg_Id; + -- Records error message Id of original undefined message. Reset to + -- No_Error_Msg after the second occurrence, where it is used to add + -- text to the original message as described above. + + Nvis : Boolean; + -- Set if the message is not visible rather than undefined + + Loc : Source_Ptr; + -- Records location of error message. Used to make sure that we do + -- not consider a, b : undefined as two separate instances, which + -- would otherwise happen, since the parser converts this sequence + -- to a : undefined; b : undefined. + + end record; + + package Urefs is new Table.Table ( + Table_Component_Type => Uref_Entry, + Table_Index_Type => Nat, + Table_Low_Bound => 1, + Table_Initial => 10, + Table_Increment => 100, + Table_Name => "Urefs"); + + Candidate_Renaming : Entity_Id; + -- Holds a candidate interpretation that appears in a subprogram renaming + -- declaration and does not match the given specification, but matches at + -- least on the first formal. Allows better error message when given + -- specification omits defaulted parameters, a common error. + + ----------------------- + -- Local Subprograms -- + ----------------------- + + procedure Analyze_Generic_Renaming + (N : Node_Id; + K : Entity_Kind); + -- Common processing for all three kinds of generic renaming declarations. + -- Enter new name and indicate that it renames the generic unit. + + procedure Analyze_Renamed_Character + (N : Node_Id; + New_S : Entity_Id; + Is_Body : Boolean); + -- Renamed entity is given by a character literal, which must belong + -- to the return type of the new entity. Is_Body indicates whether the + -- declaration is a renaming_as_body. If the original declaration has + -- already been frozen (because of an intervening body, e.g.) the body of + -- the function must be built now. The same applies to the following + -- various renaming procedures. + + procedure Analyze_Renamed_Dereference + (N : Node_Id; + New_S : Entity_Id; + Is_Body : Boolean); + -- Renamed entity is given by an explicit dereference. Prefix must be a + -- conformant access_to_subprogram type. + + procedure Analyze_Renamed_Entry + (N : Node_Id; + New_S : Entity_Id; + Is_Body : Boolean); + -- If the renamed entity in a subprogram renaming is an entry or protected + -- subprogram, build a body for the new entity whose only statement is a + -- call to the renamed entity. + + procedure Analyze_Renamed_Family_Member + (N : Node_Id; + New_S : Entity_Id; + Is_Body : Boolean); + -- Used when the renamed entity is an indexed component. The prefix must + -- denote an entry family. + + procedure Attribute_Renaming (N : Node_Id); + -- Analyze renaming of attribute as function. The renaming declaration N + -- is rewritten as a function body that returns the attribute reference + -- applied to the formals of the function. + + procedure Check_Frozen_Renaming (N : Node_Id; Subp : Entity_Id); + -- A renaming_as_body may occur after the entity of the original decla- + -- ration has been frozen. In that case, the body of the new entity must + -- be built now, because the usual mechanism of building the renamed + -- body at the point of freezing will not work. Subp is the subprogram + -- for which N provides the Renaming_As_Body. + + procedure Check_Library_Unit_Renaming (N : Node_Id; Old_E : Entity_Id); + -- Verify that the entity in a renaming declaration that is a library unit + -- is itself a library unit and not a nested unit or subunit. Also check + -- that if the renaming is a child unit of a generic parent, then the + -- renamed unit must also be a child unit of that parent. Finally, verify + -- that a renamed generic unit is not an implicit child declared within + -- an instance of the parent. + + procedure Chain_Use_Clause (N : Node_Id); + -- Chain use clause onto list of uses clauses headed by First_Use_Clause + -- in the top scope table entry. + + function Has_Implicit_Character_Literal (N : Node_Id) return Boolean; + -- Find a type derived from Character or Wide_Character in the prefix of N. + -- Used to resolved qualified names whose selector is a character literal. + + function Find_Renamed_Entity + (N : Node_Id; + Nam : Node_Id; + New_S : Entity_Id; + Is_Actual : Boolean := False) return Entity_Id; + -- Find the renamed entity that corresponds to the given parameter profile + -- in a subprogram renaming declaration. The renamed entity may be an + -- operator, a subprogram, an entry, or a protected operation. Is_Actual + -- indicates that the renaming is the one generated for an actual subpro- + -- gram in an instance, for which special visibility checks apply. + + procedure Inherit_Renamed_Profile (New_S : Entity_Id; Old_S : Entity_Id); + -- A subprogram defined by a renaming declaration inherits the parameter + -- profile of the renamed entity. The subtypes given in the subprogram + -- specification are discarded and replaced with those of the renamed + -- subprogram, which are then used to recheck the default values. + + procedure Premature_Usage (N : Node_Id); + -- Diagnose usage of an entity before it is visible. + + procedure Write_Info; + -- Write debugging information on entities declared in current scope + + procedure Write_Scopes; + pragma Warnings (Off, Write_Scopes); + -- Debugging information: dump all entities on scope stack + + -------------------------------- + -- Analyze_Exception_Renaming -- + -------------------------------- + + -- The language only allows a single identifier, but the tree holds + -- an identifier list. The parser has already issued an error message + -- if there is more than one element in the list. + + procedure Analyze_Exception_Renaming (N : Node_Id) is + Id : constant Node_Id := Defining_Identifier (N); + Nam : constant Node_Id := Name (N); + + begin + Enter_Name (Id); + Analyze (Nam); + + Set_Ekind (Id, E_Exception); + Set_Exception_Code (Id, Uint_0); + Set_Etype (Id, Standard_Exception_Type); + Set_Is_Pure (Id, Is_Pure (Current_Scope)); + + if not Is_Entity_Name (Nam) or else + Ekind (Entity (Nam)) /= E_Exception + then + Error_Msg_N ("invalid exception name in renaming", Nam); + else + if Present (Renamed_Object (Entity (Nam))) then + Set_Renamed_Object (Id, Renamed_Object (Entity (Nam))); + else + Set_Renamed_Object (Id, Entity (Nam)); + end if; + end if; + end Analyze_Exception_Renaming; + + --------------------------- + -- Analyze_Expanded_Name -- + --------------------------- + + procedure Analyze_Expanded_Name (N : Node_Id) is + begin + -- If the entity pointer is already set, this is an internal node, or + -- a node that is analyzed more than once, after a tree modification. + -- In such a case there is no resolution to perform, just set the type. + -- For completeness, analyze prefix as well. + + if Present (Entity (N)) then + if Is_Type (Entity (N)) then + Set_Etype (N, Entity (N)); + else + Set_Etype (N, Etype (Entity (N))); + end if; + + Analyze (Prefix (N)); + return; + else + Find_Expanded_Name (N); + end if; + end Analyze_Expanded_Name; + + ---------------------------------------- + -- Analyze_Generic_Function_Renaming -- + ---------------------------------------- + + procedure Analyze_Generic_Function_Renaming (N : Node_Id) is + begin + Analyze_Generic_Renaming (N, E_Generic_Function); + end Analyze_Generic_Function_Renaming; + + --------------------------------------- + -- Analyze_Generic_Package_Renaming -- + --------------------------------------- + + procedure Analyze_Generic_Package_Renaming (N : Node_Id) is + begin + -- Apply the Text_IO Kludge here, since we may be renaming + -- one of the subpackages of Text_IO, then join common routine. + + Text_IO_Kludge (Name (N)); + + Analyze_Generic_Renaming (N, E_Generic_Package); + end Analyze_Generic_Package_Renaming; + + ----------------------------------------- + -- Analyze_Generic_Procedure_Renaming -- + ----------------------------------------- + + procedure Analyze_Generic_Procedure_Renaming (N : Node_Id) is + begin + Analyze_Generic_Renaming (N, E_Generic_Procedure); + end Analyze_Generic_Procedure_Renaming; + + ------------------------------ + -- Analyze_Generic_Renaming -- + ------------------------------ + + procedure Analyze_Generic_Renaming + (N : Node_Id; + K : Entity_Kind) + is + New_P : Entity_Id := Defining_Entity (N); + Old_P : Entity_Id; + Inst : Boolean := False; -- prevent junk warning + + begin + Generate_Definition (New_P); + + if Current_Scope /= Standard_Standard then + Set_Is_Pure (New_P, Is_Pure (Current_Scope)); + end if; + + if Nkind (Name (N)) = N_Selected_Component then + Check_Generic_Child_Unit (Name (N), Inst); + else + Analyze (Name (N)); + end if; + + if not Is_Entity_Name (Name (N)) then + Error_Msg_N ("expect entity name in renaming declaration", Name (N)); + Old_P := Any_Id; + else + Old_P := Entity (Name (N)); + end if; + + Enter_Name (New_P); + Set_Ekind (New_P, K); + + if Etype (Old_P) = Any_Type then + null; + + elsif Ekind (Old_P) /= K then + Error_Msg_N ("invalid generic unit name", Name (N)); + + else + if Present (Renamed_Object (Old_P)) then + Set_Renamed_Object (New_P, Renamed_Object (Old_P)); + else + Set_Renamed_Object (New_P, Old_P); + end if; + + Set_Etype (New_P, Etype (Old_P)); + Set_Has_Completion (New_P); + + if In_Open_Scopes (Old_P) then + Error_Msg_N ("within its scope, generic denotes its instance", N); + end if; + + Check_Library_Unit_Renaming (N, Old_P); + end if; + + end Analyze_Generic_Renaming; + + ----------------------------- + -- Analyze_Object_Renaming -- + ----------------------------- + + procedure Analyze_Object_Renaming (N : Node_Id) is + Id : constant Entity_Id := Defining_Identifier (N); + Dec : Node_Id; + Nam : constant Node_Id := Name (N); + S : constant Entity_Id := Subtype_Mark (N); + T : Entity_Id; + T2 : Entity_Id; + + begin + Set_Is_Pure (Id, Is_Pure (Current_Scope)); + Enter_Name (Id); + + -- The renaming of a component that depends on a discriminant + -- requires an actual subtype, because in subsequent use of the object + -- Gigi will be unable to locate the actual bounds. This explicit step + -- is required when the renaming is generated in removing side effects + -- of an already-analyzed expression. + + if Nkind (Nam) = N_Selected_Component + and then Analyzed (Nam) + then + T := Etype (Nam); + Dec := Build_Actual_Subtype_Of_Component (Etype (Nam), Nam); + + if Present (Dec) then + Insert_Action (N, Dec); + T := Defining_Identifier (Dec); + Set_Etype (Nam, T); + end if; + + else + Find_Type (S); + T := Entity (S); + Analyze_And_Resolve (Nam, T); + end if; + + -- An object renaming requires an exact match of the type; + -- class-wide matching is not allowed. + + if Is_Class_Wide_Type (T) + and then Base_Type (Etype (Nam)) /= Base_Type (T) + then + Wrong_Type (Nam, T); + end if; + + T2 := Etype (Nam); + Set_Ekind (Id, E_Variable); + Init_Size_Align (Id); + + if T = Any_Type or else Etype (Nam) = Any_Type then + return; + + -- Verify that the renamed entity is an object or a function call. + -- It may have been rewritten in several ways. + + elsif Is_Object_Reference (Nam) then + + if Comes_From_Source (N) + and then Is_Dependent_Component_Of_Mutable_Object (Nam) + then + Error_Msg_N + ("illegal renaming of discriminant-dependent component", Nam); + else + null; + end if; + + -- A static function call may have been folded into a literal + + elsif Nkind (Original_Node (Nam)) = N_Function_Call + + -- When expansion is disabled, attribute reference is not + -- rewritten as function call. Otherwise it may be rewritten + -- as a conversion, so check original node. + + or else (Nkind (Original_Node (Nam)) = N_Attribute_Reference + and then Is_Function_Attribute_Name + (Attribute_Name (Original_Node (Nam)))) + + -- Weird but legal, equivalent to renaming a function call. + + or else (Is_Entity_Name (Nam) + and then Ekind (Entity (Nam)) = E_Enumeration_Literal) + + or else (Nkind (Nam) = N_Type_Conversion + and then Is_Tagged_Type (Entity (Subtype_Mark (Nam)))) + then + null; + + else + if Nkind (Nam) = N_Type_Conversion then + Error_Msg_N + ("renaming of conversion only allowed for tagged types", Nam); + + else + Error_Msg_N ("expect object name in renaming", Nam); + end if; + + end if; + + Set_Etype (Id, T2); + + if not Is_Variable (Nam) then + Set_Ekind (Id, E_Constant); + Set_Not_Source_Assigned (Id, True); + Set_Is_True_Constant (Id, True); + end if; + + Set_Renamed_Object (Id, Nam); + end Analyze_Object_Renaming; + + ------------------------------ + -- Analyze_Package_Renaming -- + ------------------------------ + + procedure Analyze_Package_Renaming (N : Node_Id) is + New_P : constant Entity_Id := Defining_Entity (N); + Old_P : Entity_Id; + Spec : Node_Id; + + begin + -- Apply Text_IO kludge here, since we may be renaming one of + -- the children of Text_IO + + Text_IO_Kludge (Name (N)); + + if Current_Scope /= Standard_Standard then + Set_Is_Pure (New_P, Is_Pure (Current_Scope)); + end if; + + Enter_Name (New_P); + Analyze (Name (N)); + if Is_Entity_Name (Name (N)) then + Old_P := Entity (Name (N)); + else + Old_P := Any_Id; + end if; + + if Etype (Old_P) = Any_Type then + Error_Msg_N + ("expect package name in renaming", Name (N)); + + elsif Ekind (Old_P) /= E_Package + and then not (Ekind (Old_P) = E_Generic_Package + and then In_Open_Scopes (Old_P)) + then + if Ekind (Old_P) = E_Generic_Package then + Error_Msg_N + ("generic package cannot be renamed as a package", Name (N)); + else + Error_Msg_Sloc := Sloc (Old_P); + Error_Msg_NE + ("expect package name in renaming, found& declared#", + Name (N), Old_P); + end if; + + -- Set basic attributes to minimize cascaded errors. + + Set_Ekind (New_P, E_Package); + Set_Etype (New_P, Standard_Void_Type); + + elsif Ekind (Old_P) = E_Package + and then From_With_Type (Old_P) + then + Error_Msg_N ("imported package cannot be renamed", Name (N)); + + else + -- Entities in the old package are accessible through the + -- renaming entity. The simplest implementation is to have + -- both packages share the entity list. + + Set_Ekind (New_P, E_Package); + Set_Etype (New_P, Standard_Void_Type); + + if Present (Renamed_Object (Old_P)) then + Set_Renamed_Object (New_P, Renamed_Object (Old_P)); + else + Set_Renamed_Object (New_P, Old_P); + end if; + + Set_Has_Completion (New_P); + + Set_First_Entity (New_P, First_Entity (Old_P)); + Set_Last_Entity (New_P, Last_Entity (Old_P)); + Set_First_Private_Entity (New_P, First_Private_Entity (Old_P)); + Check_Library_Unit_Renaming (N, Old_P); + Generate_Reference (Old_P, Name (N)); + + -- If this is the renaming declaration of a package instantiation + -- within itself, it is the declaration that ends the list of actuals + -- for the instantiation. At this point, the subtypes that rename + -- the actuals are flagged as generic, to avoid spurious ambiguities + -- if the actuals for two distinct formals happen to coincide. If + -- the actual is a private type, the subtype has a private completion + -- that is flagged in the same fashion. + + -- Resolution is identical to what is was in the original generic. + -- On exit from the generic instance, these are turned into regular + -- subtypes again, so they are compatible with types in their class. + + if not Is_Generic_Instance (Old_P) then + return; + else + Spec := Specification (Unit_Declaration_Node (Old_P)); + end if; + + if Nkind (Spec) = N_Package_Specification + and then Present (Generic_Parent (Spec)) + and then Old_P = Current_Scope + and then Chars (New_P) = Chars (Generic_Parent (Spec)) + then + declare + E : Entity_Id := First_Entity (Old_P); + begin + while Present (E) + and then E /= New_P + loop + if Is_Type (E) + and then Nkind (Parent (E)) = N_Subtype_Declaration + then + Set_Is_Generic_Actual_Type (E); + + if Is_Private_Type (E) + and then Present (Full_View (E)) + then + Set_Is_Generic_Actual_Type (Full_View (E)); + end if; + end if; + + Next_Entity (E); + end loop; + end; + end if; + end if; + + end Analyze_Package_Renaming; + + ------------------------------- + -- Analyze_Renamed_Character -- + ------------------------------- + + procedure Analyze_Renamed_Character + (N : Node_Id; + New_S : Entity_Id; + Is_Body : Boolean) + is + C : constant Node_Id := Name (N); + + begin + if Ekind (New_S) = E_Function then + Resolve (C, Etype (New_S)); + + if Is_Body then + Check_Frozen_Renaming (N, New_S); + end if; + + else + Error_Msg_N ("character literal can only be renamed as function", N); + end if; + end Analyze_Renamed_Character; + + --------------------------------- + -- Analyze_Renamed_Dereference -- + --------------------------------- + + procedure Analyze_Renamed_Dereference + (N : Node_Id; + New_S : Entity_Id; + Is_Body : Boolean) + is + Nam : constant Node_Id := Name (N); + P : constant Node_Id := Prefix (Nam); + Typ : Entity_Id; + I : Interp_Index; + It : Interp; + + begin + if not Is_Overloaded (P) then + + if Ekind (Etype (Nam)) /= E_Subprogram_Type + or else not Type_Conformant (Etype (Nam), New_S) then + Error_Msg_N ("designated type does not match specification", P); + else + Resolve (P, Etype (P)); + end if; + + return; + + else + Typ := Any_Type; + Get_First_Interp (Nam, I, It); + + while Present (It.Nam) loop + + if Ekind (It.Nam) = E_Subprogram_Type + and then Type_Conformant (It.Nam, New_S) then + + if Typ /= Any_Id then + Error_Msg_N ("ambiguous renaming", P); + return; + else + Typ := It.Nam; + end if; + end if; + + Get_Next_Interp (I, It); + end loop; + + if Typ = Any_Type then + Error_Msg_N ("designated type does not match specification", P); + else + Resolve (N, Typ); + + if Is_Body then + Check_Frozen_Renaming (N, New_S); + end if; + end if; + end if; + end Analyze_Renamed_Dereference; + + --------------------------- + -- Analyze_Renamed_Entry -- + --------------------------- + + procedure Analyze_Renamed_Entry + (N : Node_Id; + New_S : Entity_Id; + Is_Body : Boolean) + is + Nam : Node_Id := Name (N); + Sel : Node_Id := Selector_Name (Nam); + Old_S : Entity_Id; + + begin + if Entity (Sel) = Any_Id then + + -- Selector is undefined on prefix. Error emitted already. + + Set_Has_Completion (New_S); + return; + end if; + + -- Otherwise, find renamed entity, and build body of New_S as a call + -- to it. + + Old_S := Find_Renamed_Entity (N, Selector_Name (Nam), New_S); + + if Old_S = Any_Id then + Error_Msg_N (" no subprogram or entry matches specification", N); + else + if Is_Body then + Check_Subtype_Conformant (New_S, Old_S, N); + Generate_Reference (New_S, Defining_Entity (N), 'b'); + Style.Check_Identifier (Defining_Entity (N), New_S); + end if; + + Inherit_Renamed_Profile (New_S, Old_S); + end if; + + Set_Convention (New_S, Convention (Old_S)); + Set_Has_Completion (New_S, Inside_A_Generic); + + if Is_Body then + Check_Frozen_Renaming (N, New_S); + end if; + end Analyze_Renamed_Entry; + + ----------------------------------- + -- Analyze_Renamed_Family_Member -- + ----------------------------------- + + procedure Analyze_Renamed_Family_Member + (N : Node_Id; + New_S : Entity_Id; + Is_Body : Boolean) + is + Nam : Node_Id := Name (N); + P : Node_Id := Prefix (Nam); + Old_S : Entity_Id; + + begin + if (Is_Entity_Name (P) and then Ekind (Entity (P)) = E_Entry_Family) + or else (Nkind (P) = N_Selected_Component + and then + Ekind (Entity (Selector_Name (P))) = E_Entry_Family) + then + if Is_Entity_Name (P) then + Old_S := Entity (P); + else + Old_S := Entity (Selector_Name (P)); + end if; + + if not Entity_Matches_Spec (Old_S, New_S) then + Error_Msg_N ("entry family does not match specification", N); + + elsif Is_Body then + Check_Subtype_Conformant (New_S, Old_S, N); + Generate_Reference (New_S, Defining_Entity (N), 'b'); + Style.Check_Identifier (Defining_Entity (N), New_S); + end if; + else + Error_Msg_N ("no entry family matches specification", N); + end if; + + Set_Has_Completion (New_S, Inside_A_Generic); + + if Is_Body then + Check_Frozen_Renaming (N, New_S); + end if; + end Analyze_Renamed_Family_Member; + + --------------------------------- + -- Analyze_Subprogram_Renaming -- + --------------------------------- + + procedure Analyze_Subprogram_Renaming (N : Node_Id) is + Nam : Node_Id := Name (N); + Spec : constant Node_Id := Specification (N); + New_S : Entity_Id; + Old_S : Entity_Id := Empty; + Rename_Spec : Entity_Id; + Is_Actual : Boolean := False; + Inst_Node : Node_Id := Empty; + Save_83 : Boolean := Ada_83; + + begin + -- We must test for the attribute renaming case before the Analyze + -- call because otherwise Sem_Attr will complain that the attribute + -- is missing an argument when it is analyzed. + + if Nkind (Nam) = N_Attribute_Reference then + Attribute_Renaming (N); + return; + end if; + + -- Check whether this declaration corresponds to the instantiation + -- of a formal subprogram. This is indicated by the presence of a + -- Corresponding_Spec that is the instantiation declaration. + + -- If this is an instantiation, the corresponding actual is frozen + -- and error messages can be made more precise. If this is a default + -- subprogram, the entity is already established in the generic, and + -- is not retrieved by visibility. If it is a default with a box, the + -- candidate interpretations, if any, have been collected when building + -- the renaming declaration. If overloaded, the proper interpretation + -- is determined in Find_Renamed_Entity. If the entity is an operator, + -- Find_Renamed_Entity applies additional visibility checks. + + if Present (Corresponding_Spec (N)) then + Is_Actual := True; + Inst_Node := Corresponding_Spec (N); + + if Is_Entity_Name (Nam) + and then Present (Entity (Nam)) + and then not Comes_From_Source (Nam) + and then not Is_Overloaded (Nam) + then + Old_S := Entity (Nam); + New_S := Analyze_Spec (Spec); + + if Ekind (Entity (Nam)) = E_Operator + and then Box_Present (Corresponding_Spec (N)) + then + Old_S := Find_Renamed_Entity (N, Name (N), New_S, Is_Actual); + end if; + + else + Analyze (Nam); + New_S := Analyze_Spec (Spec); + end if; + + Set_Corresponding_Spec (N, Empty); + + else + -- Renamed entity must be analyzed first, to avoid being hidden by + -- new name (which might be the same in a generic instance). + + Analyze (Nam); + + -- The renaming defines a new overloaded entity, which is analyzed + -- like a subprogram declaration. + + New_S := Analyze_Spec (Spec); + end if; + + if Current_Scope /= Standard_Standard then + Set_Is_Pure (New_S, Is_Pure (Current_Scope)); + end if; + + Rename_Spec := Find_Corresponding_Spec (N); + + if Present (Rename_Spec) then + + -- Renaming_As_Body. Renaming declaration is the completion of + -- the declaration of Rename_Spec. We will build an actual body + -- for it at the freezing point. + + Set_Corresponding_Spec (N, Rename_Spec); + Set_Corresponding_Body (Unit_Declaration_Node (Rename_Spec), New_S); + + -- The body is created when the entity is frozen. If the context + -- is generic, freeze_all is not invoked, so we need to indicate + -- that the entity has a completion. + + Set_Has_Completion (Rename_Spec, Inside_A_Generic); + + if Ada_83 and then Comes_From_Source (N) then + Error_Msg_N ("(Ada 83) renaming cannot serve as a body", N); + end if; + + Set_Convention (New_S, Convention (Rename_Spec)); + Check_Fully_Conformant (New_S, Rename_Spec); + Set_Public_Status (New_S); + + -- Indicate that the entity in the declaration functions like + -- the corresponding body, and is not a new entity. + + Set_Ekind (New_S, E_Subprogram_Body); + New_S := Rename_Spec; + + else + Generate_Definition (New_S); + New_Overloaded_Entity (New_S); + if Is_Entity_Name (Nam) + and then Is_Intrinsic_Subprogram (Entity (Nam)) + then + null; + else + Check_Delayed_Subprogram (New_S); + end if; + end if; + + -- There is no need for elaboration checks on the new entity, which + -- may be called before the next freezing point where the body will + -- appear. + + Set_Suppress_Elaboration_Checks (New_S, True); + + if Etype (Nam) = Any_Type then + Set_Has_Completion (New_S); + return; + + elsif Nkind (Nam) = N_Selected_Component then + + -- Renamed entity is an entry or protected subprogram. For those + -- cases an explicit body is built (at the point of freezing of + -- this entity) that contains a call to the renamed entity. + + Analyze_Renamed_Entry (N, New_S, Present (Rename_Spec)); + return; + + elsif Nkind (Nam) = N_Explicit_Dereference then + + -- Renamed entity is designated by access_to_subprogram expression. + -- Must build body to encapsulate call, as in the entry case. + + Analyze_Renamed_Dereference (N, New_S, Present (Rename_Spec)); + return; + + elsif Nkind (Nam) = N_Indexed_Component then + Analyze_Renamed_Family_Member (N, New_S, Present (Rename_Spec)); + return; + + elsif Nkind (Nam) = N_Character_Literal then + Analyze_Renamed_Character (N, New_S, Present (Rename_Spec)); + return; + + elsif (not Is_Entity_Name (Nam) + and then Nkind (Nam) /= N_Operator_Symbol) + or else not Is_Overloadable (Entity (Nam)) + then + Error_Msg_N ("expect valid subprogram name in renaming", N); + return; + + end if; + + -- Most common case: subprogram renames subprogram. No body is + -- generated in this case, so we must indicate that the declaration + -- is complete as is. + + if No (Rename_Spec) then + Set_Has_Completion (New_S); + end if; + + -- Find the renamed entity that matches the given specification. + -- Disable Ada_83 because there is no requirement of full conformance + -- between renamed entity and new entity, even though the same circuit + -- is used. + + Ada_83 := False; + + if No (Old_S) then + Old_S := Find_Renamed_Entity (N, Name (N), New_S, Is_Actual); + end if; + + if Old_S /= Any_Id then + + if Is_Actual + and then Box_Present (Inst_Node) + then + -- This is an implicit reference to the default actual + + Generate_Reference (Old_S, Nam, Typ => 'i', Force => True); + else + Generate_Reference (Old_S, Nam); + end if; + + -- For a renaming-as-body, require subtype conformance, + -- but if the declaration being completed has not been + -- frozen, then inherit the convention of the renamed + -- subprogram prior to checking conformance (unless the + -- renaming has an explicit convention established; the + -- rule stated in the RM doesn't seem to address this ???). + + if Present (Rename_Spec) then + Generate_Reference (Rename_Spec, Defining_Entity (Spec), 'b'); + Style.Check_Identifier (Defining_Entity (Spec), Rename_Spec); + + if not Is_Frozen (Rename_Spec) + and then not Has_Convention_Pragma (Rename_Spec) + then + Set_Convention (New_S, Convention (Old_S)); + end if; + + Check_Frozen_Renaming (N, Rename_Spec); + Check_Subtype_Conformant (New_S, Old_S, Spec); + + elsif Ekind (Old_S) /= E_Operator then + Check_Mode_Conformant (New_S, Old_S); + + if Is_Actual + and then Error_Posted (New_S) + then + Error_Msg_NE ("invalid actual subprogram: & #!", N, Old_S); + end if; + end if; + + if No (Rename_Spec) then + + -- The parameter profile of the new entity is that of the renamed + -- entity: the subtypes given in the specification are irrelevant. + + Inherit_Renamed_Profile (New_S, Old_S); + + -- A call to the subprogram is transformed into a call to the + -- renamed entity. This is transitive if the renamed entity is + -- itself a renaming. + + if Present (Alias (Old_S)) then + Set_Alias (New_S, Alias (Old_S)); + else + Set_Alias (New_S, Old_S); + end if; + + -- Note that we do not set Is_Instrinsic_Subprogram if we have + -- a renaming as body, since the entity in this case is not an + -- intrinsic (it calls an intrinsic, but we have a real body + -- for this call, and it is in this body that the required + -- intrinsic processing will take place). + + Set_Is_Intrinsic_Subprogram + (New_S, Is_Intrinsic_Subprogram (Old_S)); + + if Ekind (Alias (New_S)) = E_Operator then + Set_Has_Delayed_Freeze (New_S, False); + end if; + + end if; + + if not Is_Actual + and then (Old_S = New_S + or else (Nkind (Nam) /= N_Expanded_Name + and then Chars (Old_S) = Chars (New_S))) + then + Error_Msg_N ("subprogram cannot rename itself", N); + end if; + + Set_Convention (New_S, Convention (Old_S)); + Set_Is_Abstract (New_S, Is_Abstract (Old_S)); + Check_Library_Unit_Renaming (N, Old_S); + + -- Pathological case: procedure renames entry in the scope of + -- its task. Entry is given by simple name, but body must be built + -- for procedure. Of course if called it will deadlock. + + if Ekind (Old_S) = E_Entry then + Set_Has_Completion (New_S, False); + Set_Alias (New_S, Empty); + end if; + + if Is_Actual then + Freeze_Before (N, Old_S); + Set_Has_Delayed_Freeze (New_S, False); + Freeze_Before (N, New_S); + + if (Ekind (Old_S) = E_Procedure or else Ekind (Old_S) = E_Function) + and then Is_Abstract (Old_S) + then + Error_Msg_N + ("abstract subprogram not allowed as generic actual", Nam); + end if; + end if; + + else + -- A common error is to assume that implicit operators for types + -- are defined in Standard, or in the scope of a subtype. In those + -- cases where the renamed entity is given with an expanded name, + -- it is worth mentioning that operators for the type are not + -- declared in the scope given by the prefix. + + if Nkind (Nam) = N_Expanded_Name + and then Nkind (Selector_Name (Nam)) = N_Operator_Symbol + and then Scope (Entity (Nam)) = Standard_Standard + then + declare + T : constant Entity_Id := + Base_Type (Etype (First_Formal (New_S))); + + begin + Error_Msg_Node_2 := Prefix (Nam); + Error_Msg_NE ("\operator for type& is not declared in&", + Prefix (Nam), T); + end; + else + Error_Msg_NE + ("no visible subprogram matches the specification for&", + Spec, New_S); + end if; + + if Present (Candidate_Renaming) then + declare + F1 : Entity_Id; + F2 : Entity_Id; + + begin + F1 := First_Formal (Candidate_Renaming); + F2 := First_Formal (New_S); + + while Present (F1) and then Present (F2) loop + Next_Formal (F1); + Next_Formal (F2); + end loop; + + if Present (F1) and then Present (Default_Value (F1)) then + if Present (Next_Formal (F1)) then + Error_Msg_NE + ("\missing specification for &" & + " and other formals with defaults", Spec, F1); + else + Error_Msg_NE + ("\missing specification for &", Spec, F1); + end if; + end if; + end; + end if; + end if; + + Ada_83 := Save_83; + end Analyze_Subprogram_Renaming; + + ------------------------- + -- Analyze_Use_Package -- + ------------------------- + + -- Resolve the package names in the use clause, and make all the visible + -- entities defined in the package potentially use-visible. If the package + -- is already in use from a previous use clause, its visible entities are + -- already use-visible. In that case, mark the occurrence as a redundant + -- use. If the package is an open scope, i.e. if the use clause occurs + -- within the package itself, ignore it. + + procedure Analyze_Use_Package (N : Node_Id) is + Pack_Name : Node_Id; + Pack : Entity_Id; + + function In_Previous_With_Clause (P : Entity_Id) return Boolean; + -- For use clauses in a context clause, the indicated package may + -- be visible and yet illegal, if it did not appear in a previous + -- with clause. + + ----------------------------- + -- In_Previous_With_Clause -- + ----------------------------- + + function In_Previous_With_Clause (P : Entity_Id) return Boolean is + Item : Node_Id; + + begin + Item := First (Context_Items (Parent (N))); + + while Present (Item) + and then Item /= N + loop + if Nkind (Item) = N_With_Clause + and then Entity (Name (Item)) = Pack + then + return True; + end if; + + Next (Item); + end loop; + + return False; + end In_Previous_With_Clause; + + -- Start of processing for Analyze_Use_Package + + begin + Set_Hidden_By_Use_Clause (N, No_Elist); + + -- Use clause is not allowed in a spec of a predefined package + -- declaration except that packages whose file name starts a-n + -- are OK (these are children of Ada.Numerics, and such packages + -- are never loaded by Rtsfind). + + if Is_Predefined_File_Name (Unit_File_Name (Current_Sem_Unit)) + and then Name_Buffer (1 .. 3) /= "a-n" + and then + Nkind (Unit (Cunit (Current_Sem_Unit))) = N_Package_Declaration + then + Error_Msg_N ("use clause not allowed in predefined spec", N); + end if; + + -- Chain clause to list of use clauses in current scope. + + if Nkind (Parent (N)) /= N_Compilation_Unit then + Chain_Use_Clause (N); + end if; + + -- Loop through package names to identify referenced packages + + Pack_Name := First (Names (N)); + + while Present (Pack_Name) loop + Analyze (Pack_Name); + + if Nkind (Parent (N)) = N_Compilation_Unit + and then Nkind (Pack_Name) = N_Expanded_Name + then + declare + Pref : Node_Id := Prefix (Pack_Name); + + begin + while Nkind (Pref) = N_Expanded_Name loop + Pref := Prefix (Pref); + end loop; + + if Entity (Pref) = Standard_Standard then + Error_Msg_N + ("predefined package Standard cannot appear" + & " in a context clause", Pref); + end if; + end; + end if; + + Next (Pack_Name); + end loop; + + -- Loop through package names to mark all entities as potentially + -- use visible. + + Pack_Name := First (Names (N)); + + while Present (Pack_Name) loop + + if Is_Entity_Name (Pack_Name) then + Pack := Entity (Pack_Name); + + if Ekind (Pack) /= E_Package + and then Etype (Pack) /= Any_Type + then + if Ekind (Pack) = E_Generic_Package then + Error_Msg_N + ("a generic package is not allowed in a use clause", + Pack_Name); + else + Error_Msg_N ("& is not a usable package", Pack_Name); + end if; + + elsif Nkind (Parent (N)) = N_Compilation_Unit + and then Nkind (Pack_Name) /= N_Expanded_Name + and then not In_Previous_With_Clause (Pack) + then + Error_Msg_N ("package is not directly visible", Pack_Name); + + elsif Applicable_Use (Pack_Name) then + Use_One_Package (Pack, N); + end if; + end if; + + Next (Pack_Name); + end loop; + + end Analyze_Use_Package; + + ---------------------- + -- Analyze_Use_Type -- + ---------------------- + + procedure Analyze_Use_Type (N : Node_Id) is + Id : Entity_Id; + + begin + Set_Hidden_By_Use_Clause (N, No_Elist); + + -- Chain clause to list of use clauses in current scope. + + if Nkind (Parent (N)) /= N_Compilation_Unit then + Chain_Use_Clause (N); + end if; + + Id := First (Subtype_Marks (N)); + + while Present (Id) loop + Find_Type (Id); + + if Entity (Id) /= Any_Type then + Use_One_Type (Id, N); + end if; + + Next (Id); + end loop; + end Analyze_Use_Type; + + -------------------- + -- Applicable_Use -- + -------------------- + + function Applicable_Use (Pack_Name : Node_Id) return Boolean is + Pack : constant Entity_Id := Entity (Pack_Name); + + begin + if In_Open_Scopes (Pack) then + return False; + + elsif In_Use (Pack) then + Set_Redundant_Use (Pack_Name, True); + return False; + + elsif Present (Renamed_Object (Pack)) + and then In_Use (Renamed_Object (Pack)) + then + Set_Redundant_Use (Pack_Name, True); + return False; + + else + return True; + end if; + end Applicable_Use; + + ------------------------ + -- Attribute_Renaming -- + ------------------------ + + procedure Attribute_Renaming (N : Node_Id) is + Loc : constant Source_Ptr := Sloc (N); + Nam : constant Node_Id := Name (N); + Spec : constant Node_Id := Specification (N); + New_S : constant Entity_Id := Defining_Unit_Name (Spec); + Aname : constant Name_Id := Attribute_Name (Nam); + + Form_Num : Nat := 0; + Expr_List : List_Id := No_List; + + Attr_Node : Node_Id; + Body_Node : Node_Id; + Param_Spec : Node_Id; + + begin + Generate_Definition (New_S); + + -- This procedure is called in the context of subprogram renaming, + -- and thus the attribute must be one that is a subprogram. All of + -- those have at least one formal parameter, with the singular + -- exception of AST_Entry (which is a real oddity, it is odd that + -- this can be renamed at all!) + + if not Is_Non_Empty_List (Parameter_Specifications (Spec)) then + if Aname /= Name_AST_Entry then + Error_Msg_N + ("subprogram renaming an attribute must have formals", N); + return; + end if; + + else + Param_Spec := First (Parameter_Specifications (Spec)); + + while Present (Param_Spec) loop + Form_Num := Form_Num + 1; + + if Nkind (Parameter_Type (Param_Spec)) /= N_Access_Definition then + Find_Type (Parameter_Type (Param_Spec)); + + -- The profile of the new entity denotes the base type (s) of + -- the types given in the specification. For access parameters + -- there are no subtypes involved. + + Rewrite (Parameter_Type (Param_Spec), + New_Reference_To + (Base_Type (Entity (Parameter_Type (Param_Spec))), Loc)); + end if; + + if No (Expr_List) then + Expr_List := New_List; + end if; + + Append_To (Expr_List, + Make_Identifier (Loc, + Chars => Chars (Defining_Identifier (Param_Spec)))); + + Next (Param_Spec); + end loop; + end if; + + -- Immediate error if too many formals. Other mismatches in numbers + -- of number of types of parameters are detected when we analyze the + -- body of the subprogram that we construct. + + if Form_Num > 2 then + Error_Msg_N ("too many formals for attribute", N); + + elsif + Aname = Name_Compose or else + Aname = Name_Exponent or else + Aname = Name_Leading_Part or else + Aname = Name_Pos or else + Aname = Name_Round or else + Aname = Name_Scaling or else + Aname = Name_Val + then + if Nkind (N) = N_Subprogram_Renaming_Declaration + and then Present (Corresponding_Spec (N)) + and then Nkind (Corresponding_Spec (N)) = + N_Formal_Subprogram_Declaration + then + Error_Msg_N + ("generic actual cannot be attribute involving universal type", + Nam); + else + Error_Msg_N + ("attribute involving a universal type cannot be renamed", + Nam); + end if; + end if; + + -- AST_Entry is an odd case. It doesn't really make much sense to + -- allow it to be renamed, but that's the DEC rule, so we have to + -- do it right. The point is that the AST_Entry call should be made + -- now, and what the function will return is the returned value. + + -- Note that there is no Expr_List in this case anyway + + if Aname = Name_AST_Entry then + + declare + Ent : Entity_Id; + Decl : Node_Id; + + begin + Ent := Make_Defining_Identifier (Loc, New_Internal_Name ('R')); + + Decl := + Make_Object_Declaration (Loc, + Defining_Identifier => Ent, + Object_Definition => + New_Occurrence_Of (RTE (RE_AST_Handler), Loc), + Expression => Nam, + Constant_Present => True); + + Set_Assignment_OK (Decl, True); + Insert_Action (N, Decl); + Attr_Node := Make_Identifier (Loc, Chars (Ent)); + end; + + -- For all other attributes, we rewrite the attribute node to have + -- a list of expressions corresponding to the subprogram formals. + -- A renaming declaration is not a freeze point, and the analysis of + -- the attribute reference should not freeze the type of the prefix. + + else + Attr_Node := + Make_Attribute_Reference (Loc, + Prefix => Prefix (Nam), + Attribute_Name => Aname, + Expressions => Expr_List); + + Set_Must_Not_Freeze (Attr_Node); + Set_Must_Not_Freeze (Prefix (Nam)); + end if; + + -- Case of renaming a function + + if Nkind (Spec) = N_Function_Specification then + + if Is_Procedure_Attribute_Name (Aname) then + Error_Msg_N ("attribute can only be renamed as procedure", Nam); + return; + end if; + + Find_Type (Subtype_Mark (Spec)); + Rewrite (Subtype_Mark (Spec), + New_Reference_To (Base_Type (Entity (Subtype_Mark (Spec))), Loc)); + + Body_Node := + Make_Subprogram_Body (Loc, + Specification => Spec, + Declarations => New_List, + Handled_Statement_Sequence => + Make_Handled_Sequence_Of_Statements (Loc, + Statements => New_List ( + Make_Return_Statement (Loc, + Expression => Attr_Node)))); + + -- Case of renaming a procedure + + else + if not Is_Procedure_Attribute_Name (Aname) then + Error_Msg_N ("attribute can only be renamed as function", Nam); + return; + end if; + + Body_Node := + Make_Subprogram_Body (Loc, + Specification => Spec, + Declarations => New_List, + Handled_Statement_Sequence => + Make_Handled_Sequence_Of_Statements (Loc, + Statements => New_List (Attr_Node))); + end if; + + Rewrite (N, Body_Node); + Analyze (N); + + Set_Etype (New_S, Base_Type (Etype (New_S))); + + -- We suppress elaboration warnings for the resulting entity, since + -- clearly they are not needed, and more particularly, in the case + -- of a generic formal subprogram, the resulting entity can appear + -- after the instantiation itself, and thus look like a bogus case + -- of access before elaboration. + + Set_Suppress_Elaboration_Warnings (New_S); + + end Attribute_Renaming; + + ---------------------- + -- Chain_Use_Clause -- + ---------------------- + + procedure Chain_Use_Clause (N : Node_Id) is + begin + Set_Next_Use_Clause (N, + Scope_Stack.Table (Scope_Stack.Last).First_Use_Clause); + Scope_Stack.Table (Scope_Stack.Last).First_Use_Clause := N; + end Chain_Use_Clause; + + ---------------------------- + -- Check_Frozen_Renaming -- + ---------------------------- + + procedure Check_Frozen_Renaming (N : Node_Id; Subp : Entity_Id) is + B_Node : Node_Id; + Old_S : Entity_Id; + + begin + if Is_Frozen (Subp) + and then not Has_Completion (Subp) + then + B_Node := + Build_Renamed_Body + (Parent (Declaration_Node (Subp)), Defining_Entity (N)); + + if Is_Entity_Name (Name (N)) then + Old_S := Entity (Name (N)); + + if not Is_Frozen (Old_S) then + Ensure_Freeze_Node (Old_S); + if No (Actions (Freeze_Node (Old_S))) then + Set_Actions (Freeze_Node (Old_S), New_List (B_Node)); + else + Append (B_Node, Actions (Freeze_Node (Old_S))); + end if; + else + Insert_After (N, B_Node); + Analyze (B_Node); + end if; + + if Is_Intrinsic_Subprogram (Old_S) + and then not In_Instance + then + Error_Msg_N + ("subprogram used in renaming_as_body cannot be intrinsic", + Name (N)); + end if; + + else + Insert_After (N, B_Node); + Analyze (B_Node); + end if; + end if; + end Check_Frozen_Renaming; + + --------------------------------- + -- Check_Library_Unit_Renaming -- + --------------------------------- + + procedure Check_Library_Unit_Renaming (N : Node_Id; Old_E : Entity_Id) is + New_E : Entity_Id; + + begin + if Nkind (Parent (N)) /= N_Compilation_Unit then + return; + + elsif Scope (Old_E) /= Standard_Standard + and then not Is_Child_Unit (Old_E) + then + Error_Msg_N ("renamed unit must be a library unit", Name (N)); + + elsif Present (Parent_Spec (N)) + and then Nkind (Unit (Parent_Spec (N))) = N_Generic_Package_Declaration + and then not Is_Child_Unit (Old_E) + then + Error_Msg_N + ("renamed unit must be a child unit of generic parent", Name (N)); + + elsif Nkind (N) in N_Generic_Renaming_Declaration + and then Nkind (Name (N)) = N_Expanded_Name + and then Is_Generic_Instance (Entity (Prefix (Name (N)))) + and then Is_Generic_Unit (Old_E) + then + Error_Msg_N + ("renamed generic unit must be a library unit", Name (N)); + + elsif Ekind (Old_E) = E_Package + or else Ekind (Old_E) = E_Generic_Package + then + -- Inherit categorization flags + + New_E := Defining_Entity (N); + Set_Is_Pure (New_E, Is_Pure (Old_E)); + Set_Is_Preelaborated (New_E, Is_Preelaborated (Old_E)); + Set_Is_Remote_Call_Interface (New_E, + Is_Remote_Call_Interface (Old_E)); + Set_Is_Remote_Types (New_E, Is_Remote_Types (Old_E)); + Set_Is_Shared_Passive (New_E, Is_Shared_Passive (Old_E)); + end if; + end Check_Library_Unit_Renaming; + + --------------- + -- End_Scope -- + --------------- + + procedure End_Scope is + Id : Entity_Id; + Prev : Entity_Id; + Outer : Entity_Id; + + begin + Id := First_Entity (Current_Scope); + + while Present (Id) loop + -- An entity in the current scope is not necessarily the first one + -- on its homonym chain. Find its predecessor if any, + -- If it is an internal entity, it will not be in the visibility + -- chain altogether, and there is nothing to unchain. + + if Id /= Current_Entity (Id) then + Prev := Current_Entity (Id); + while Present (Prev) + and then Present (Homonym (Prev)) + and then Homonym (Prev) /= Id + loop + Prev := Homonym (Prev); + end loop; + + -- Skip to end of loop if Id is not in the visibility chain + + if No (Prev) or else Homonym (Prev) /= Id then + goto Next_Ent; + end if; + + else + Prev := Empty; + end if; + + Outer := Homonym (Id); + Set_Is_Immediately_Visible (Id, False); + + while Present (Outer) and then Scope (Outer) = Current_Scope loop + Outer := Homonym (Outer); + end loop; + + -- Reset homonym link of other entities, but do not modify link + -- between entities in current scope, so that the back-end can have + -- a proper count of local overloadings. + + if No (Prev) then + Set_Name_Entity_Id (Chars (Id), Outer); + + elsif Scope (Prev) /= Scope (Id) then + Set_Homonym (Prev, Outer); + end if; + + <<Next_Ent>> + Next_Entity (Id); + end loop; + + -- If the scope generated freeze actions, place them before the + -- current declaration and analyze them. Type declarations and + -- the bodies of initialization procedures can generate such nodes. + -- We follow the parent chain until we reach a list node, which is + -- the enclosing list of declarations. If the list appears within + -- a protected definition, move freeze nodes outside the protected + -- type altogether. + + if Present + (Scope_Stack.Table (Scope_Stack.Last).Pending_Freeze_Actions) + then + declare + Decl : Node_Id; + L : constant List_Id := Scope_Stack.Table + (Scope_Stack.Last).Pending_Freeze_Actions; + + begin + if Is_Itype (Current_Scope) then + Decl := Associated_Node_For_Itype (Current_Scope); + else + Decl := Parent (Current_Scope); + end if; + + Pop_Scope; + + while not (Is_List_Member (Decl)) + or else Nkind (Parent (Decl)) = N_Protected_Definition + or else Nkind (Parent (Decl)) = N_Task_Definition + loop + Decl := Parent (Decl); + end loop; + + Insert_List_Before_And_Analyze (Decl, L); + end; + + else + Pop_Scope; + end if; + + end End_Scope; + + --------------------- + -- End_Use_Clauses -- + --------------------- + + procedure End_Use_Clauses (Clause : Node_Id) is + U : Node_Id := Clause; + + begin + while Present (U) loop + if Nkind (U) = N_Use_Package_Clause then + End_Use_Package (U); + elsif Nkind (U) = N_Use_Type_Clause then + End_Use_Type (U); + end if; + + Next_Use_Clause (U); + end loop; + end End_Use_Clauses; + + --------------------- + -- End_Use_Package -- + --------------------- + + procedure End_Use_Package (N : Node_Id) is + Pack_Name : Node_Id; + Pack : Entity_Id; + Id : Entity_Id; + Elmt : Elmt_Id; + + begin + Pack_Name := First (Names (N)); + + while Present (Pack_Name) loop + Pack := Entity (Pack_Name); + + if Ekind (Pack) = E_Package then + + if In_Open_Scopes (Pack) then + null; + + elsif not Redundant_Use (Pack_Name) then + Set_In_Use (Pack, False); + Id := First_Entity (Pack); + + while Present (Id) loop + + -- Preserve use-visibility of operators whose formals have + -- a type that is use_visible thanks to a previous use_type + -- clause. + + if Nkind (Id) = N_Defining_Operator_Symbol + and then + (In_Use (Etype (First_Formal (Id))) + or else + (Present (Next_Formal (First_Formal (Id))) + and then In_Use (Etype (Next_Formal + (First_Formal (Id)))))) + then + null; + + else + Set_Is_Potentially_Use_Visible (Id, False); + end if; + + if Is_Private_Type (Id) + and then Present (Full_View (Id)) + then + Set_Is_Potentially_Use_Visible (Full_View (Id), False); + end if; + + Next_Entity (Id); + end loop; + + if Present (Renamed_Object (Pack)) then + Set_In_Use (Renamed_Object (Pack), False); + end if; + + if Chars (Pack) = Name_System + and then Scope (Pack) = Standard_Standard + and then Present_System_Aux + then + Id := First_Entity (System_Aux_Id); + + while Present (Id) loop + Set_Is_Potentially_Use_Visible (Id, False); + + if Is_Private_Type (Id) + and then Present (Full_View (Id)) + then + Set_Is_Potentially_Use_Visible (Full_View (Id), False); + end if; + + Next_Entity (Id); + end loop; + + Set_In_Use (System_Aux_Id, False); + end if; + + else + Set_Redundant_Use (Pack_Name, False); + end if; + + end if; + + Next (Pack_Name); + end loop; + + if Present (Hidden_By_Use_Clause (N)) then + Elmt := First_Elmt (Hidden_By_Use_Clause (N)); + + while Present (Elmt) loop + Set_Is_Immediately_Visible (Node (Elmt)); + Next_Elmt (Elmt); + end loop; + + Set_Hidden_By_Use_Clause (N, No_Elist); + end if; + end End_Use_Package; + + ------------------ + -- End_Use_Type -- + ------------------ + + procedure End_Use_Type (N : Node_Id) is + Id : Entity_Id; + Op_List : Elist_Id; + Elmt : Elmt_Id; + T : Entity_Id; + + begin + Id := First (Subtype_Marks (N)); + + while Present (Id) loop + T := Entity (Id); + + if T = Any_Type then + null; + + -- Note that the use_Type clause may mention a subtype of the + -- type whose primitive operations have been made visible. Here + -- as elsewhere, it is the base type that matters for visibility. + + elsif In_Open_Scopes (Scope (Base_Type (T))) then + null; + + elsif not Redundant_Use (Id) then + Set_In_Use (T, False); + Set_In_Use (Base_Type (T), False); + Op_List := Collect_Primitive_Operations (T); + Elmt := First_Elmt (Op_List); + + while Present (Elmt) loop + + if Nkind (Node (Elmt)) = N_Defining_Operator_Symbol then + Set_Is_Potentially_Use_Visible (Node (Elmt), False); + end if; + + Next_Elmt (Elmt); + end loop; + end if; + + Next (Id); + end loop; + end End_Use_Type; + + ---------------------- + -- Find_Direct_Name -- + ---------------------- + + procedure Find_Direct_Name (N : Node_Id) is + E : Entity_Id; + E2 : Entity_Id; + Msg : Boolean; + + Inst : Entity_Id := Empty; + -- Enclosing instance, if any. + + Homonyms : Entity_Id; + -- Saves start of homonym chain + + Nvis_Entity : Boolean; + -- Set True to indicate that at there is at least one entity on the + -- homonym chain which, while not visible, is visible enough from the + -- user point of view to warrant an error message of "not visible" + -- rather than undefined. + + function From_Actual_Package (E : Entity_Id) return Boolean; + -- Returns true if the entity is declared in a package that is + -- an actual for a formal package of the current instance. Such an + -- entity requires special handling because it may be use-visible + -- but hides directly visible entities defined outside the instance. + + function Known_But_Invisible (E : Entity_Id) return Boolean; + -- This function determines whether the entity E (which is not + -- visible) can reasonably be considered to be known to the writer + -- of the reference. This is a heuristic test, used only for the + -- purposes of figuring out whether we prefer to complain that an + -- entity is undefined or invisible (and identify the declaration + -- of the invisible entity in the latter case). The point here is + -- that we don't want to complain that something is invisible and + -- then point to something entirely mysterious to the writer. + + procedure Nvis_Messages; + -- Called if there are no visible entries for N, but there is at least + -- one non-directly visible, or hidden declaration. This procedure + -- outputs an appropriate set of error messages. + + procedure Undefined (Nvis : Boolean); + -- This function is called if the current node has no corresponding + -- visible entity or entities. The value set in Msg indicates whether + -- an error message was generated (multiple error messages for the + -- same variable are generally suppressed, see body for details). + -- Msg is True if an error message was generated, False if not. This + -- value is used by the caller to determine whether or not to output + -- additional messages where appropriate. The parameter is set False + -- to get the message "X is undefined", and True to get the message + -- "X is not visible". + + ------------------------- + -- From_Actual_Package -- + ------------------------- + + function From_Actual_Package (E : Entity_Id) return Boolean is + Scop : constant Entity_Id := Scope (E); + Act : Entity_Id; + + begin + if not In_Instance then + return False; + else + Inst := Current_Scope; + + while Present (Inst) + and then Ekind (Inst) /= E_Package + and then not Is_Generic_Instance (Inst) + loop + Inst := Scope (Inst); + end loop; + + if No (Inst) then + return False; + end if; + + Act := First_Entity (Inst); + + while Present (Act) loop + if Ekind (Act) = E_Package then + + -- Check for end of actuals list + + if Renamed_Object (Act) = Inst then + return False; + + elsif Present (Associated_Formal_Package (Act)) + and then Renamed_Object (Act) = Scop + then + -- Entity comes from (instance of) formal package + + return True; + + else + Next_Entity (Act); + end if; + + else + Next_Entity (Act); + end if; + end loop; + + return False; + end if; + end From_Actual_Package; + + ------------------------- + -- Known_But_Invisible -- + ------------------------- + + function Known_But_Invisible (E : Entity_Id) return Boolean is + Fname : File_Name_Type; + + begin + -- Entities in Standard are always considered to be known + + if Sloc (E) <= Standard_Location then + return True; + + -- An entity that does not come from source is always considered + -- to be unknown, since it is an artifact of code expansion. + + elsif not Comes_From_Source (E) then + return False; + + -- In gnat internal mode, we consider all entities known + + elsif GNAT_Mode then + return True; + end if; + + -- Here we have an entity that is not from package Standard, and + -- which comes from Source. See if it comes from an internal file. + + Fname := Unit_File_Name (Get_Source_Unit (E)); + + -- Case of from internal file + + if Is_Internal_File_Name (Fname) then + + -- Private part entities in internal files are never considered + -- to be known to the writer of normal application code. + + if Is_Hidden (E) then + return False; + end if; + + -- Entities from System packages other than System and + -- System.Storage_Elements are not considered to be known. + -- System.Auxxxx files are also considered known to the user. + + -- Should refine this at some point to generally distinguish + -- between known and unknown internal files ??? + + Get_Name_String (Fname); + + return + Name_Len < 2 + or else + Name_Buffer (1 .. 2) /= "s-" + or else + Name_Buffer (3 .. 8) = "stoele" + or else + Name_Buffer (3 .. 5) = "aux"; + + -- If not an internal file, then entity is definitely known, + -- even if it is in a private part (the message generated will + -- note that it is in a private part) + + else + return True; + end if; + end Known_But_Invisible; + + ------------------- + -- Nvis_Messages -- + ------------------- + + procedure Nvis_Messages is + Ent : Entity_Id; + Hidden : Boolean := False; + + begin + Undefined (Nvis => True); + + if Msg then + + -- First loop does hidden declarations + + Ent := Homonyms; + while Present (Ent) loop + if Is_Potentially_Use_Visible (Ent) then + + if not Hidden then + Error_Msg_N ("multiple use clauses cause hiding!", N); + Hidden := True; + end if; + + Error_Msg_Sloc := Sloc (Ent); + Error_Msg_N ("hidden declaration#!", N); + end if; + + Ent := Homonym (Ent); + end loop; + + -- If we found hidden declarations, then that's enough, don't + -- bother looking for non-visible declarations as well. + + if Hidden then + return; + end if; + + -- Second loop does non-directly visible declarations + + Ent := Homonyms; + while Present (Ent) loop + if not Is_Potentially_Use_Visible (Ent) then + + -- Do not bother the user with unknown entities + + if not Known_But_Invisible (Ent) then + goto Continue; + end if; + + Error_Msg_Sloc := Sloc (Ent); + + -- Output message noting that there is a non-visible + -- declaration, distinguishing the private part case. + + if Is_Hidden (Ent) then + Error_Msg_N ("non-visible (private) declaration#!", N); + else + Error_Msg_N ("non-visible declaration#!", N); + end if; + end if; + + <<Continue>> + Ent := Homonym (Ent); + end loop; + + end if; + end Nvis_Messages; + + --------------- + -- Undefined -- + --------------- + + procedure Undefined (Nvis : Boolean) is + Emsg : Error_Msg_Id; + + begin + -- A very specialized error check, if the undefined variable is + -- a case tag, and the case type is an enumeration type, check + -- for a possible misspelling, and if so, modify the identifier + + -- Named aggregate should also be handled similarly ??? + + if Nkind (N) = N_Identifier + and then Nkind (Parent (N)) = N_Case_Statement_Alternative + then + Get_Name_String (Chars (N)); + + declare + Case_Str : constant String := Name_Buffer (1 .. Name_Len); + Case_Stm : constant Node_Id := Parent (Parent (N)); + Case_Typ : constant Entity_Id := Etype (Expression (Case_Stm)); + + Lit : Node_Id; + + begin + if Is_Enumeration_Type (Case_Typ) + and then Case_Typ /= Standard_Character + and then Case_Typ /= Standard_Wide_Character + then + Lit := First_Literal (Case_Typ); + Get_Name_String (Chars (Lit)); + + if Chars (Lit) /= Chars (N) + and then Is_Bad_Spelling_Of + (Case_Str, Name_Buffer (1 .. Name_Len)) + then + Error_Msg_Node_2 := Lit; + Error_Msg_N + ("& is undefined, assume misspelling of &", N); + Rewrite (N, New_Occurrence_Of (Lit, Sloc (N))); + return; + end if; + + Lit := Next_Literal (Lit); + end if; + end; + end if; + + -- Normal processing + + Set_Entity (N, Any_Id); + Set_Etype (N, Any_Type); + + -- We use the table Urefs to keep track of entities for which we + -- have issued errors for undefined references. Multiple errors + -- for a single name are normally suppressed, however we modify + -- the error message to alert the programmer to this effect. + + for J in Urefs.First .. Urefs.Last loop + if Chars (N) = Chars (Urefs.Table (J).Node) then + if Urefs.Table (J).Err /= No_Error_Msg + and then Sloc (N) /= Urefs.Table (J).Loc + then + Error_Msg_Node_1 := Urefs.Table (J).Node; + + if Urefs.Table (J).Nvis then + Change_Error_Text (Urefs.Table (J).Err, + "& is not visible (more references follow)"); + else + Change_Error_Text (Urefs.Table (J).Err, + "& is undefined (more references follow)"); + end if; + + Urefs.Table (J).Err := No_Error_Msg; + end if; + + -- Although we will set Msg False, and thus suppress the + -- message, we also set Error_Posted True, to avoid any + -- cascaded messages resulting from the undefined reference. + + Msg := False; + Set_Error_Posted (N, True); + return; + end if; + end loop; + + -- If entry not found, this is first undefined occurrence + + if Nvis then + Error_Msg_N ("& is not visible!", N); + Emsg := Get_Msg_Id; + + else + Error_Msg_N ("& is undefined!", N); + Emsg := Get_Msg_Id; + + -- A very bizarre special check, if the undefined identifier + -- is put or put_line, then add a special error message (since + -- this is a very common error for beginners to make). + + if Chars (N) = Name_Put or else Chars (N) = Name_Put_Line then + Error_Msg_N ("\possible missing with of 'Text_'I'O!", N); + end if; + + -- Now check for possible misspellings + + Get_Name_String (Chars (N)); + + declare + E : Entity_Id; + Ematch : Entity_Id := Empty; + + Last_Name_Id : constant Name_Id := + Name_Id (Nat (First_Name_Id) + + Name_Entries_Count - 1); + + S : constant String (1 .. Name_Len) := + Name_Buffer (1 .. Name_Len); + + begin + for N in First_Name_Id .. Last_Name_Id loop + E := Get_Name_Entity_Id (N); + + if Present (E) + and then (Is_Immediately_Visible (E) + or else + Is_Potentially_Use_Visible (E)) + then + Get_Name_String (N); + + if Is_Bad_Spelling_Of + (Name_Buffer (1 .. Name_Len), S) + then + Ematch := E; + exit; + end if; + end if; + end loop; + + if Present (Ematch) then + Error_Msg_NE ("\possible misspelling of&", N, Ematch); + end if; + end; + end if; + + -- Make entry in undefined references table unless the full + -- errors switch is set, in which case by refraining from + -- generating the table entry, we guarantee that we get an + -- error message for every undefined reference. + + if not All_Errors_Mode then + Urefs.Increment_Last; + Urefs.Table (Urefs.Last).Node := N; + Urefs.Table (Urefs.Last).Err := Emsg; + Urefs.Table (Urefs.Last).Nvis := Nvis; + Urefs.Table (Urefs.Last).Loc := Sloc (N); + end if; + + Msg := True; + end Undefined; + + -- Start of processing for Find_Direct_Name + + begin + -- If the entity pointer is already set, this is an internal node, or + -- a node that is analyzed more than once, after a tree modification. + -- In such a case there is no resolution to perform, just set the type. + + if Present (Entity (N)) then + if Is_Type (Entity (N)) then + Set_Etype (N, Entity (N)); + + else + declare + Entyp : constant Entity_Id := Etype (Entity (N)); + + begin + -- One special case here. If the Etype field is already set, + -- and references the packed array type corresponding to the + -- etype of the referenced entity, then leave it alone. This + -- happens for trees generated from Exp_Pakd, where expressions + -- can be deliberately "mis-typed" to the packed array type. + + if Is_Array_Type (Entyp) + and then Is_Packed (Entyp) + and then Present (Etype (N)) + and then Etype (N) = Packed_Array_Type (Entyp) + then + null; + + -- If not that special case, then just reset the Etype + + else + Set_Etype (N, Etype (Entity (N))); + end if; + end; + end if; + + return; + end if; + + -- Here if Entity pointer was not set, we need full visibility analysis + -- First we generate debugging output if the debug E flag is set. + + if Debug_Flag_E then + Write_Str ("Looking for "); + Write_Name (Chars (N)); + Write_Eol; + end if; + + Homonyms := Current_Entity (N); + Nvis_Entity := False; + + E := Homonyms; + while Present (E) loop + + -- If entity is immediately visible or potentially use + -- visible, then process the entity and we are done. + + if Is_Immediately_Visible (E) then + goto Immediately_Visible_Entity; + + elsif Is_Potentially_Use_Visible (E) then + goto Potentially_Use_Visible_Entity; + + -- Note if a known but invisible entity encountered + + elsif Known_But_Invisible (E) then + Nvis_Entity := True; + end if; + + -- Move to next entity in chain and continue search + + E := Homonym (E); + end loop; + + -- If no entries on homonym chain that were potentially visible, + -- and no entities reasonably considered as non-visible, then + -- we have a plain undefined reference, with no additional + -- explanation required! + + if not Nvis_Entity then + Undefined (Nvis => False); + return; + + -- Otherwise there is at least one entry on the homonym chain that + -- is reasonably considered as being known and non-visible. + + else + Nvis_Messages; + return; + end if; + + -- Processing for a potentially use visible entry found. We must search + -- the rest of the homonym chain for two reasons. First, if there is a + -- directly visible entry, then none of the potentially use-visible + -- entities are directly visible (RM 8.4(10)). Second, we need to check + -- for the case of multiple potentially use-visible entries hiding one + -- another and as a result being non-directly visible (RM 8.4(11)). + + <<Potentially_Use_Visible_Entity>> declare + Only_One_Visible : Boolean := True; + All_Overloadable : Boolean := Is_Overloadable (E); + + begin + E2 := Homonym (E); + + while Present (E2) loop + if Is_Immediately_Visible (E2) then + + -- If the use-visible entity comes from the actual for a + -- formal package, it hides a directly visible entity from + -- outside the instance. + + if From_Actual_Package (E) + and then Scope_Depth (E2) < Scope_Depth (Inst) + then + goto Found; + else + E := E2; + goto Immediately_Visible_Entity; + end if; + + elsif Is_Potentially_Use_Visible (E2) then + Only_One_Visible := False; + All_Overloadable := All_Overloadable and Is_Overloadable (E2); + end if; + + E2 := Homonym (E2); + end loop; + + -- On falling through this loop, we have checked that there are no + -- immediately visible entities. Only_One_Visible is set if exactly + -- one potentially use visible entity exists. All_Overloadable is + -- set if all the potentially use visible entities are overloadable. + -- The condition for legality is that either there is one potentially + -- use visible entity, or if there is more than one, then all of them + -- are overloadable. + + if Only_One_Visible or All_Overloadable then + goto Found; + + -- If there is more than one potentially use-visible entity and at + -- least one of them non-overloadable, we have an error (RM 8.4(11). + -- Note that E points to the first such entity on the homonym list. + -- Special case: if one of the entities is declared in an actual + -- package, it was visible in the generic, and takes precedence over + -- other entities that are potentially use-visible. + + else + if In_Instance then + E2 := E; + + while Present (E2) loop + if Is_Generic_Instance (Scope (E2)) then + E := E2; + goto Found; + end if; + + E2 := Homonym (E2); + end loop; + + Nvis_Messages; + return; + + else + Nvis_Messages; + return; + end if; + end if; + end; + + -- Come here with E set to the first immediately visible entity on + -- the homonym chain. This is the one we want unless there is another + -- immediately visible entity further on in the chain for a more + -- inner scope (RM 8.3(8)). + + <<Immediately_Visible_Entity>> declare + Level : Int; + Scop : Entity_Id; + + begin + -- Find scope level of initial entity. When compiling through + -- Rtsfind, the previous context is not completely invisible, and + -- an outer entity may appear on the chain, whose scope is below + -- the entry for Standard that delimits the current scope stack. + -- Indicate that the level for this spurious entry is outside of + -- the current scope stack. + + Level := Scope_Stack.Last; + loop + Scop := Scope_Stack.Table (Level).Entity; + exit when Scop = Scope (E); + Level := Level - 1; + exit when Scop = Standard_Standard; + end loop; + + -- Now search remainder of homonym chain for more inner entry + -- If the entity is Standard itself, it has no scope, and we + -- compare it with the stack entry directly. + + E2 := Homonym (E); + while Present (E2) loop + if Is_Immediately_Visible (E2) then + for J in Level + 1 .. Scope_Stack.Last loop + if Scope_Stack.Table (J).Entity = Scope (E2) + or else Scope_Stack.Table (J).Entity = E2 + then + Level := J; + E := E2; + exit; + end if; + end loop; + end if; + + E2 := Homonym (E2); + end loop; + + -- At the end of that loop, E is the innermost immediately + -- visible entity, so we are all set. + end; + + -- Come here with entity found, and stored in E + + <<Found>> begin + + if Comes_From_Source (N) + and then Is_Remote_Access_To_Subprogram_Type (E) + and then Expander_Active + then + Rewrite (N, + New_Occurrence_Of (Equivalent_Type (E), Sloc (N))); + return; + end if; + + Set_Entity (N, E); + -- Why no Style_Check here??? + + if Is_Type (E) then + Set_Etype (N, E); + else + Set_Etype (N, Get_Full_View (Etype (E))); + end if; + + if Debug_Flag_E then + Write_Str (" found "); + Write_Entity_Info (E, " "); + end if; + + -- If the Ekind of the entity is Void, it means that all homonyms + -- are hidden from all visibility (RM 8.3(5,14-20)). However, this + -- test is skipped if the current scope is a record and the name is + -- a pragma argument expression (case of Atomic and Volatile pragmas + -- and possibly other similar pragmas added later, which are allowed + -- to reference components in the current record). + + if Ekind (E) = E_Void + and then + (not Is_Record_Type (Current_Scope) + or else Nkind (Parent (N)) /= N_Pragma_Argument_Association) + then + Premature_Usage (N); + + -- If the entity is overloadable, collect all interpretations + -- of the name for subsequent overload resolution. We optimize + -- a bit here to do this only if we have an overloadable entity + -- that is not on its own on the homonym chain. + + elsif Is_Overloadable (E) + and then (Present (Homonym (E)) or else Current_Entity (N) /= E) + then + Collect_Interps (N); + + -- If no homonyms were visible, the entity is unambiguous. + + if not Is_Overloaded (N) then + Generate_Reference (E, N); + end if; + + -- Case of non-overloadable entity, set the entity providing that + -- we do not have the case of a discriminant reference within a + -- default expression. Such references are replaced with the + -- corresponding discriminal, which is the formal corresponding to + -- to the discriminant in the initialization procedure. + + -- This replacement must not be done if we are currently processing + -- a generic spec or body. + + -- The replacement is not done either for a task discriminant that + -- appears in a default expression of an entry parameter. See + -- Expand_Discriminant in exp_ch2 for details on their handling. + + else + -- Entity is unambiguous, indicate that it is referenced here + -- One slightly odd case is that we do not want to set the + -- Referenced flag if the entity is a label, and the identifier + -- is the label in the source, since this is not a reference + -- from the point of view of the user + + if Nkind (Parent (N)) = N_Label then + declare + R : constant Boolean := Referenced (E); + + begin + Generate_Reference (E, N); + Set_Referenced (E, R); + end; + + else + Generate_Reference (E, N); + end if; + + if not In_Default_Expression + or else Ekind (E) /= E_Discriminant + or else Inside_A_Generic + then + Set_Entity_With_Style_Check (N, E); + + elsif Is_Concurrent_Type (Scope (E)) then + declare + P : Node_Id := Parent (N); + + begin + while Present (P) + and then Nkind (P) /= N_Parameter_Specification + and then Nkind (P) /= N_Component_Declaration + loop + P := Parent (P); + end loop; + + if Present (P) + and then Nkind (P) = N_Parameter_Specification + then + null; + else + Set_Entity (N, Discriminal (E)); + end if; + end; + + else + Set_Entity (N, Discriminal (E)); + end if; + end if; + end; + end Find_Direct_Name; + + ------------------------ + -- Find_Expanded_Name -- + ------------------------ + + -- This routine searches the homonym chain of the entity until it finds + -- an entity declared in the scope denoted by the prefix. If the entity + -- is private, it may nevertheless be immediately visible, if we are in + -- the scope of its declaration. + + procedure Find_Expanded_Name (N : Node_Id) is + Candidate : Entity_Id := Empty; + Selector : constant Node_Id := Selector_Name (N); + P_Name : Entity_Id; + O_Name : Entity_Id; + Id : Entity_Id; + + begin + P_Name := Entity (Prefix (N)); + O_Name := P_Name; + + -- If the prefix is a renamed package, look for the entity + -- in the original package. + + if Ekind (P_Name) = E_Package + and then Present (Renamed_Object (P_Name)) + then + P_Name := Renamed_Object (P_Name); + + -- Rewrite node with entity field pointing to renamed object + + Rewrite (Prefix (N), New_Copy (Prefix (N))); + Set_Entity (Prefix (N), P_Name); + + -- If the prefix is an object of a concurrent type, look for + -- the entity in the associated task or protected type. + + elsif Is_Concurrent_Type (Etype (P_Name)) then + P_Name := Etype (P_Name); + end if; + + Id := Current_Entity (Selector); + + while Present (Id) loop + + if Scope (Id) = P_Name then + Candidate := Id; + + if Is_Child_Unit (Id) then + exit when + (Is_Visible_Child_Unit (Id) + or else Is_Immediately_Visible (Id)); + + else + exit when + (not Is_Hidden (Id) or else Is_Immediately_Visible (Id)); + end if; + end if; + + Id := Homonym (Id); + end loop; + + if No (Id) + and then (Ekind (P_Name) = E_Procedure + or else + Ekind (P_Name) = E_Function) + and then Is_Generic_Instance (P_Name) + then + -- Expanded name denotes entity in (instance of) generic subprogram. + -- The entity may be in the subprogram instance, or may denote one of + -- the formals, which is declared in the enclosing wrapper package. + + P_Name := Scope (P_Name); + Id := Current_Entity (Selector); + + while Present (Id) loop + exit when Scope (Id) = P_Name; + Id := Homonym (Id); + end loop; + end if; + + if No (Id) or else Chars (Id) /= Chars (Selector) then + + Set_Etype (N, Any_Type); + + -- If we are looking for an entity defined in System, try to + -- find it in the child package that may have been provided as + -- an extension to System. The Extend_System pragma will have + -- supplied the name of the extension, which may have to be loaded. + + if Chars (P_Name) = Name_System + and then Scope (P_Name) = Standard_Standard + and then Present (System_Extend_Pragma_Arg) + and then Present_System_Aux (N) + then + Set_Entity (Prefix (N), System_Aux_Id); + Find_Expanded_Name (N); + return; + + elsif (Nkind (Selector) = N_Operator_Symbol + and then Has_Implicit_Operator (N)) + then + -- There is an implicit instance of the predefined operator in + -- the given scope. The operator entity is defined in Standard. + -- Has_Implicit_Operator makes the node into an Expanded_Name. + + return; + + elsif Nkind (Selector) = N_Character_Literal + and then Has_Implicit_Character_Literal (N) + then + -- If there is no literal defined in the scope denoted by the + -- prefix, the literal may belong to (a type derived from) + -- Standard_Character, for which we have no explicit literals. + + return; + + else + -- If the prefix is a single concurrent object, use its + -- name in the error message, rather than that of the + -- anonymous type. + + if Is_Concurrent_Type (P_Name) + and then Is_Internal_Name (Chars (P_Name)) + then + Error_Msg_Node_2 := Entity (Prefix (N)); + else + Error_Msg_Node_2 := P_Name; + end if; + + if P_Name = System_Aux_Id then + P_Name := Scope (P_Name); + Set_Entity (Prefix (N), P_Name); + end if; + + if Present (Candidate) then + + if Is_Child_Unit (Candidate) then + Error_Msg_N + ("missing with_clause for child unit &", Selector); + else + Error_Msg_NE ("& is not a visible entity of&", N, Selector); + end if; + + else + -- Within the instantiation of a child unit, the prefix may + -- denote the parent instance, but the selector has the + -- name of the original child. Find whether we are within + -- the corresponding instance, and get the proper entity, which + -- can only be an enclosing scope. + + if O_Name /= P_Name + and then In_Open_Scopes (P_Name) + and then Is_Generic_Instance (P_Name) + then + declare + S : Entity_Id := Current_Scope; + P : Entity_Id; + + begin + for J in reverse 0 .. Scope_Stack.Last loop + S := Scope_Stack.Table (J).Entity; + + exit when S = Standard_Standard; + + if Ekind (S) = E_Function + or else Ekind (S) = E_Package + or else Ekind (S) = E_Procedure + then + P := Generic_Parent (Specification + (Unit_Declaration_Node (S))); + + if Present (P) + and then Chars (Scope (P)) = Chars (O_Name) + and then Chars (P) = Chars (Selector) + then + Id := S; + goto found; + end if; + end if; + + end loop; + end; + end if; + + if (Chars (P_Name) = Name_Ada + and then Scope (P_Name) = Standard_Standard) + then + Error_Msg_Node_2 := Selector; + Error_Msg_NE + ("\missing with for `&.&`", N, P_Name); + + -- If this is a selection from a dummy package, then + -- suppress the error message, of course the entity + -- is missing if the package is missing! + + elsif Sloc (Error_Msg_Node_2) = No_Location then + null; + + -- Here we have the case of an undefined component + + else + + Error_Msg_NE ("& not declared in&", N, Selector); + + -- Check for misspelling of some entity in prefix. + + Id := First_Entity (P_Name); + Get_Name_String (Chars (Selector)); + + declare + S : constant String (1 .. Name_Len) := + Name_Buffer (1 .. Name_Len); + begin + while Present (Id) loop + Get_Name_String (Chars (Id)); + if Is_Bad_Spelling_Of + (Name_Buffer (1 .. Name_Len), S) + and then not Is_Internal_Name (Chars (Id)) + then + Error_Msg_NE + ("possible misspelling of&", Selector, Id); + exit; + end if; + + Next_Entity (Id); + end loop; + end; + + -- Specialize the message if this may be an instantiation + -- of a child unit that was not mentioned in the context. + + if Nkind (Parent (N)) = N_Package_Instantiation + and then Is_Generic_Instance (Entity (Prefix (N))) + and then Is_Compilation_Unit + (Generic_Parent (Parent (Entity (Prefix (N))))) + then + Error_Msg_NE + ("\possible missing with clause on child unit&", + N, Selector); + end if; + end if; + end if; + + Id := Any_Id; + end if; + end if; + + <<found>> + if Comes_From_Source (N) + and then Is_Remote_Access_To_Subprogram_Type (Id) + then + Id := Equivalent_Type (Id); + Set_Chars (Selector, Chars (Id)); + end if; + + if Ekind (P_Name) = E_Package + and then From_With_Type (P_Name) + then + if From_With_Type (Id) + or else (Ekind (Id) = E_Package and then From_With_Type (Id)) + then + null; + else + Error_Msg_N + ("imported package can only be used to access imported type", + N); + end if; + end if; + + if Is_Task_Type (P_Name) + and then ((Ekind (Id) = E_Entry + and then Nkind (Parent (N)) /= N_Attribute_Reference) + or else + (Ekind (Id) = E_Entry_Family + and then + Nkind (Parent (Parent (N))) /= N_Attribute_Reference)) + then + -- It is an entry call after all, either to the current task + -- (which will deadlock) or to an enclosing task. + + Analyze_Selected_Component (N); + return; + end if; + + Change_Selected_Component_To_Expanded_Name (N); + Set_Entity_With_Style_Check (N, Id); + Generate_Reference (Id, N); + + if Is_Type (Id) then + Set_Etype (N, Id); + else + Set_Etype (N, Get_Full_View (Etype (Id))); + end if; + + -- If the Ekind of the entity is Void, it means that all homonyms + -- are hidden from all visibility (RM 8.3(5,14-20)). + + if Ekind (Id) = E_Void then + Premature_Usage (N); + + elsif Is_Overloadable (Id) + and then Present (Homonym (Id)) + then + declare + H : Entity_Id := Homonym (Id); + + begin + while Present (H) loop + if Scope (H) = Scope (Id) then + Collect_Interps (N); + exit; + end if; + + H := Homonym (H); + end loop; + end; + end if; + + if Nkind (Selector_Name (N)) = N_Operator_Symbol + and then Scope (Id) /= Standard_Standard + then + -- In addition to user-defined operators in the given scope, + -- there may be an implicit instance of the predefined + -- operator. The operator (defined in Standard) is found + -- in Has_Implicit_Operator, and added to the interpretations. + -- Procedure Add_One_Interp will determine which hides which. + + if Has_Implicit_Operator (N) then + null; + end if; + end if; + end Find_Expanded_Name; + + ------------------------- + -- Find_Renamed_Entity -- + ------------------------- + + function Find_Renamed_Entity + (N : Node_Id; + Nam : Node_Id; + New_S : Entity_Id; + Is_Actual : Boolean := False) return Entity_Id + is + I : Interp_Index; + I1 : Interp_Index := 0; -- Suppress junk warnings + It : Interp; + It1 : Interp; + Old_S : Entity_Id; + Inst : Entity_Id; + + function Enclosing_Instance return Entity_Id; + -- If the renaming determines the entity for the default of a formal + -- subprogram nested within another instance, choose the innermost + -- candidate. This is because if the formal has a box, and we are within + -- an enclosing instance where some candidate interpretations are local + -- to this enclosing instance, we know that the default was properly + -- resolved when analyzing the generic, so we prefer the local + -- candidates to those that are external. This is not always the case + -- but is a reasonable heuristic on the use of nested generics. + -- The proper solution requires a full renaming model. + + function Within (Inner, Outer : Entity_Id) return Boolean; + -- Determine whether a candidate subprogram is defined within + -- the enclosing instance. If yes, it has precedence over outer + -- candidates. + + function Is_Visible_Operation (Op : Entity_Id) return Boolean; + -- If the renamed entity is an implicit operator, check whether it is + -- visible because its operand type is properly visible. This + -- check applies to explicit renamed entities that appear in the + -- source in a renaming declaration or a formal subprogram instance, + -- but not to default generic actuals with a name. + + ------------------------ + -- Enclosing_Instance -- + ------------------------ + + function Enclosing_Instance return Entity_Id is + S : Entity_Id; + + begin + if not Is_Generic_Instance (Current_Scope) + and then not Is_Actual + then + return Empty; + end if; + + S := Scope (Current_Scope); + + while S /= Standard_Standard loop + + if Is_Generic_Instance (S) then + return S; + end if; + + S := Scope (S); + end loop; + + return Empty; + end Enclosing_Instance; + + -------------------------- + -- Is_Visible_Operation -- + -------------------------- + + function Is_Visible_Operation (Op : Entity_Id) return Boolean is + Scop : Entity_Id; + Typ : Entity_Id; + Btyp : Entity_Id; + + begin + if Ekind (Op) /= E_Operator + or else Scope (Op) /= Standard_Standard + or else (In_Instance + and then + (not Is_Actual + or else Present (Enclosing_Instance))) + then + return True; + + else + -- For a fixed point type operator, check the resulting type, + -- because it may be a mixed mode integer * fixed operation. + + if Present (Next_Formal (First_Formal (New_S))) + and then Is_Fixed_Point_Type (Etype (New_S)) + then + Typ := Etype (New_S); + else + Typ := Etype (First_Formal (New_S)); + end if; + + Btyp := Base_Type (Typ); + + if Nkind (Nam) /= N_Expanded_Name then + return (In_Open_Scopes (Scope (Btyp)) + or else Is_Potentially_Use_Visible (Btyp) + or else In_Use (Btyp) + or else In_Use (Scope (Btyp))); + + else + Scop := Entity (Prefix (Nam)); + + if Ekind (Scop) = E_Package + and then Present (Renamed_Object (Scop)) + then + Scop := Renamed_Object (Scop); + end if; + + -- Operator is visible if prefix of expanded name denotes + -- scope of type, or else type type is defined in System_Aux + -- and the prefix denotes System. + + return Scope (Btyp) = Scop + or else (Scope (Btyp) = System_Aux_Id + and then Scope (Scope (Btyp)) = Scop); + end if; + end if; + end Is_Visible_Operation; + + ------------ + -- Within -- + ------------ + + function Within (Inner, Outer : Entity_Id) return Boolean is + Sc : Entity_Id := Scope (Inner); + + begin + while Sc /= Standard_Standard loop + + if Sc = Outer then + return True; + else + Sc := Scope (Sc); + end if; + end loop; + + return False; + end Within; + + -- Start of processing for Find_Renamed_Entry + + begin + Old_S := Any_Id; + Candidate_Renaming := Empty; + + if not Is_Overloaded (Nam) then + if Entity_Matches_Spec (Entity (Nam), New_S) + and then Is_Visible_Operation (Entity (Nam)) + then + Old_S := Entity (Nam); + + elsif + Present (First_Formal (Entity (Nam))) + and then Present (First_Formal (New_S)) + and then (Base_Type (Etype (First_Formal (Entity (Nam)))) + = Base_Type (Etype (First_Formal (New_S)))) + then + Candidate_Renaming := Entity (Nam); + end if; + + else + Get_First_Interp (Nam, I, It); + + while Present (It.Nam) loop + + if Entity_Matches_Spec (It.Nam, New_S) + and then Is_Visible_Operation (It.Nam) + then + if Old_S /= Any_Id then + + -- Note: The call to Disambiguate only happens if a + -- previous interpretation was found, in which case I1 + -- has received a value. + + It1 := Disambiguate (Nam, I1, I, Etype (Old_S)); + + if It1 = No_Interp then + + Inst := Enclosing_Instance; + + if Present (Inst) then + + if Within (It.Nam, Inst) then + return (It.Nam); + + elsif Within (Old_S, Inst) then + return (Old_S); + + else + Error_Msg_N ("ambiguous renaming", N); + return Old_S; + end if; + + else + Error_Msg_N ("ambiguous renaming", N); + return Old_S; + end if; + + else + Old_S := It1.Nam; + exit; + end if; + + else + I1 := I; + Old_S := It.Nam; + end if; + + elsif + Present (First_Formal (It.Nam)) + and then Present (First_Formal (New_S)) + and then (Base_Type (Etype (First_Formal (It.Nam))) + = Base_Type (Etype (First_Formal (New_S)))) + then + Candidate_Renaming := It.Nam; + end if; + + Get_Next_Interp (I, It); + end loop; + + Set_Entity (Nam, Old_S); + Set_Is_Overloaded (Nam, False); + end if; + + return Old_S; + end Find_Renamed_Entity; + + ----------------------------- + -- Find_Selected_Component -- + ----------------------------- + + procedure Find_Selected_Component (N : Node_Id) is + P : Node_Id := Prefix (N); + + P_Name : Entity_Id; + -- Entity denoted by prefix + + P_Type : Entity_Id; + -- and its type + + Nam : Node_Id; + + begin + Analyze (P); + + if Nkind (P) = N_Error then + return; + + -- If the selector already has an entity, the node has been + -- constructed in the course of expansion, and is known to be + -- valid. Do not verify that it is defined for the type (it may + -- be a private component used in the expansion of record equality). + + elsif Present (Entity (Selector_Name (N))) then + + if No (Etype (N)) + or else Etype (N) = Any_Type + then + declare + Sel_Name : Node_Id := Selector_Name (N); + Selector : Entity_Id := Entity (Sel_Name); + C_Etype : Node_Id; + + begin + Set_Etype (Sel_Name, Etype (Selector)); + + if not Is_Entity_Name (P) then + Resolve (P, Etype (P)); + end if; + + -- Build an actual subtype except for the first parameter + -- of an init_proc, where this actual subtype is by + -- definition incorrect, since the object is uninitialized + -- (and does not even have defined discriminants etc.) + + if Is_Entity_Name (P) + and then Ekind (Entity (P)) = E_Function + then + Nam := New_Copy (P); + + if Is_Overloaded (P) then + Save_Interps (P, Nam); + end if; + + Rewrite (P, + Make_Function_Call (Sloc (P), Name => Nam)); + Analyze_Call (P); + Analyze_Selected_Component (N); + return; + + elsif Ekind (Selector) = E_Component + and then (not Is_Entity_Name (P) + or else Chars (Entity (P)) /= Name_uInit) + then + C_Etype := + Build_Actual_Subtype_Of_Component ( + Etype (Selector), N); + else + C_Etype := Empty; + end if; + + if No (C_Etype) then + C_Etype := Etype (Selector); + else + Insert_Action (N, C_Etype); + C_Etype := Defining_Identifier (C_Etype); + end if; + + Set_Etype (N, C_Etype); + end; + + -- If this is the name of an entry or protected operation, and + -- the prefix is an access type, insert an explicit dereference, + -- so that entry calls are treated uniformly. + + if Is_Access_Type (Etype (P)) + and then Is_Concurrent_Type (Designated_Type (Etype (P))) + then + declare + New_P : Node_Id := + Make_Explicit_Dereference (Sloc (P), + Prefix => Relocate_Node (P)); + begin + Rewrite (P, New_P); + Set_Etype (P, Designated_Type (Etype (Prefix (P)))); + end; + end if; + + -- If the selected component appears within a default expression + -- and it has an actual subtype, the pre-analysis has not yet + -- completed its analysis, because Insert_Actions is disabled in + -- that context. Within the init_proc of the enclosing type we + -- must complete this analysis, if an actual subtype was created. + + elsif Inside_Init_Proc then + declare + Typ : constant Entity_Id := Etype (N); + Decl : constant Node_Id := Declaration_Node (Typ); + + begin + if Nkind (Decl) = N_Subtype_Declaration + and then not Analyzed (Decl) + and then Is_List_Member (Decl) + and then No (Parent (Decl)) + then + Remove (Decl); + Insert_Action (N, Decl); + end if; + end; + end if; + + return; + + elsif Is_Entity_Name (P) then + P_Name := Entity (P); + + -- The prefix may denote an enclosing type which is the completion + -- of an incomplete type declaration. + + if Is_Type (P_Name) then + Set_Entity (P, Get_Full_View (P_Name)); + Set_Etype (P, Entity (P)); + P_Name := Entity (P); + end if; + + P_Type := Base_Type (Etype (P)); + + if Debug_Flag_E then + Write_Str ("Found prefix type to be "); + Write_Entity_Info (P_Type, " "); Write_Eol; + end if; + + -- First check for components of a record object (not the + -- result of a call, which is handled below). + + if Is_Appropriate_For_Record (P_Type) + and then not Is_Overloadable (P_Name) + and then not Is_Type (P_Name) + then + -- Selected component of record. Type checking will validate + -- name of selector. + + Analyze_Selected_Component (N); + + elsif Is_Appropriate_For_Entry_Prefix (P_Type) + and then not In_Open_Scopes (P_Name) + and then (not Is_Concurrent_Type (Etype (P_Name)) + or else not In_Open_Scopes (Etype (P_Name))) + then + -- Call to protected operation or entry. Type checking is + -- needed on the prefix. + + Analyze_Selected_Component (N); + + elsif (In_Open_Scopes (P_Name) + and then Ekind (P_Name) /= E_Void + and then not Is_Overloadable (P_Name)) + or else (Is_Concurrent_Type (Etype (P_Name)) + and then In_Open_Scopes (Etype (P_Name))) + then + -- Prefix denotes an enclosing loop, block, or task, i.e. an + -- enclosing construct that is not a subprogram or accept. + + Find_Expanded_Name (N); + + elsif Ekind (P_Name) = E_Package then + Find_Expanded_Name (N); + + elsif Is_Overloadable (P_Name) then + + -- The subprogram may be a renaming (of an enclosing scope) as + -- in the case of the name of the generic within an instantiation. + + if (Ekind (P_Name) = E_Procedure + or else Ekind (P_Name) = E_Function) + and then Present (Alias (P_Name)) + and then Is_Generic_Instance (Alias (P_Name)) + then + P_Name := Alias (P_Name); + end if; + + if Is_Overloaded (P) then + + -- The prefix must resolve to a unique enclosing construct. + + declare + Found : Boolean := False; + I : Interp_Index; + It : Interp; + + begin + Get_First_Interp (P, I, It); + + while Present (It.Nam) loop + + if In_Open_Scopes (It.Nam) then + if Found then + Error_Msg_N ( + "prefix must be unique enclosing scope", N); + Set_Entity (N, Any_Id); + Set_Etype (N, Any_Type); + return; + + else + Found := True; + P_Name := It.Nam; + end if; + end if; + + Get_Next_Interp (I, It); + end loop; + end; + end if; + + if In_Open_Scopes (P_Name) then + Set_Entity (P, P_Name); + Set_Is_Overloaded (P, False); + Find_Expanded_Name (N); + + else + -- If no interpretation as an expanded name is possible, it + -- must be a selected component of a record returned by a + -- function call. Reformat prefix as a function call, the + -- rest is done by type resolution. If the prefix is a + -- procedure or entry, as is P.X; this is an error. + + if Ekind (P_Name) /= E_Function + and then (not Is_Overloaded (P) + or else + Nkind (Parent (N)) = N_Procedure_Call_Statement) + then + + -- Prefix may mention a package that is hidden by a local + -- declaration: let the user know. + + if Present (Homonym (P_Name)) then + + while Present (P_Name) loop + exit when Ekind (P_Name) = E_Package; + P_Name := Homonym (P_Name); + end loop; + + if Present (P_Name) then + Error_Msg_Sloc := Sloc (Entity (Prefix (N))); + + Error_Msg_NE + ("package& is hidden by declaration#", + N, P_Name); + + Set_Entity (Prefix (N), P_Name); + Find_Expanded_Name (N); + return; + else + P_Name := Entity (Prefix (N)); + end if; + end if; + + Error_Msg_NE + ("invalid prefix in selected component&", N, P_Name); + Change_Selected_Component_To_Expanded_Name (N); + Set_Entity (N, Any_Id); + Set_Etype (N, Any_Type); + + else + Nam := New_Copy (P); + Save_Interps (P, Nam); + Rewrite (P, + Make_Function_Call (Sloc (P), Name => Nam)); + Analyze_Call (P); + Analyze_Selected_Component (N); + end if; + end if; + + -- Remaining cases generate various error messages + + else + -- Format node as expanded name, to avoid cascaded errors + + Change_Node (N, N_Expanded_Name); + Set_Prefix (N, P); + Set_Entity (N, Any_Id); + Set_Etype (N, Any_Type); + + -- Set_Selector_Name (N, Empty); ???? + + -- Issue error message, but avoid this if error issued already. + -- Use identifier of prefix if one is available. + + if P_Name = Any_Id then + null; + + elsif Ekind (P_Name) = E_Void then + Premature_Usage (P); + + elsif Nkind (P) /= N_Attribute_Reference then + Error_Msg_N ( + "invalid prefix in selected component&", P); + + else + Error_Msg_N ( + "invalid prefix in selected component", P); + end if; + end if; + + else + -- If prefix is not the name of an entity, it must be an expression, + -- whose type is appropriate for a record. This is determined by + -- type resolution. + + Analyze_Selected_Component (N); + end if; + end Find_Selected_Component; + + --------------- + -- Find_Type -- + --------------- + + procedure Find_Type (N : Node_Id) is + C : Entity_Id; + Typ : Entity_Id; + T : Entity_Id; + T_Name : Entity_Id; + + begin + if N = Error then + return; + + elsif Nkind (N) = N_Attribute_Reference then + + -- Class attribute. This is only valid in Ada 95 mode, but we don't + -- do a check, since the tagged type referenced could only exist if + -- we were in 95 mode when it was declared (or, if we were in Ada + -- 83 mode, then an error message would already have been issued). + + if Attribute_Name (N) = Name_Class then + Check_Restriction (No_Dispatch, N); + Find_Type (Prefix (N)); + + -- Propagate error from bad prefix + + if Etype (Prefix (N)) = Any_Type then + Set_Entity (N, Any_Type); + Set_Etype (N, Any_Type); + return; + end if; + + T := Base_Type (Entity (Prefix (N))); + + -- Case of non-tagged type + + if not Is_Tagged_Type (T) then + if Ekind (T) = E_Incomplete_Type then + + -- It is legal to denote the class type of an incomplete + -- type. The full type will have to be tagged, of course. + + Set_Is_Tagged_Type (T); + Make_Class_Wide_Type (T); + Set_Entity (N, Class_Wide_Type (T)); + Set_Etype (N, Class_Wide_Type (T)); + + elsif Ekind (T) = E_Private_Type + and then not Is_Generic_Type (T) + and then In_Private_Part (Scope (T)) + then + -- The Class attribute can be applied to an untagged + -- private type fulfilled by a tagged type prior to + -- the full type declaration (but only within the + -- parent package's private part). Create the class-wide + -- type now and check that the full type is tagged + -- later during its analysis. Note that we do not + -- mark the private type as tagged, unlike the case + -- of incomplete types, because the type must still + -- appear untagged to outside units. + + if not Present (Class_Wide_Type (T)) then + Make_Class_Wide_Type (T); + end if; + + Set_Entity (N, Class_Wide_Type (T)); + Set_Etype (N, Class_Wide_Type (T)); + + else + -- Should we introduce a type Any_Tagged and use + -- Wrong_Type here, it would be a bit more consistent??? + + Error_Msg_NE + ("tagged type required, found}", + Prefix (N), First_Subtype (T)); + Set_Entity (N, Any_Type); + return; + end if; + + -- Case of tagged type + + else + C := Class_Wide_Type (Entity (Prefix (N))); + Set_Entity_With_Style_Check (N, C); + Generate_Reference (C, N); + Set_Etype (N, C); + + if From_With_Type (C) + and then Nkind (Parent (N)) /= N_Access_Definition + and then not Analyzed (T) + then + Error_Msg_N + ("imported class-wide type can only be used" & + " for access parameters", N); + end if; + end if; + + -- Base attribute, allowed in Ada 95 mode only + + elsif Attribute_Name (N) = Name_Base then + if Ada_83 and then Comes_From_Source (N) then + Error_Msg_N + ("(Ada 83) Base attribute not allowed in subtype mark", N); + + else + Find_Type (Prefix (N)); + Typ := Entity (Prefix (N)); + + if Sloc (Typ) = Standard_Location + and then Base_Type (Typ) = Typ + and then Warn_On_Redundant_Constructs + then + Error_Msg_NE + ("?redudant attribute, & is its own base type", N, Typ); + end if; + + T := Base_Type (Typ); + Set_Entity (N, T); + Set_Etype (N, T); + + -- Rewrite attribute reference with type itself (see similar + -- processing in Analyze_Attribute, case Base) + + Rewrite (N, + New_Reference_To (Entity (N), Sloc (N))); + Set_Etype (N, T); + end if; + + -- All other attributes are invalid in a subtype mark + + else + Error_Msg_N ("invalid attribute in subtype mark", N); + end if; + + else + Analyze (N); + + if Is_Entity_Name (N) then + T_Name := Entity (N); + else + Error_Msg_N ("subtype mark required in this context", N); + Set_Etype (N, Any_Type); + return; + end if; + + if T_Name = Any_Id or else Etype (N) = Any_Type then + + -- Undefined id. Make it into a valid type + + Set_Entity (N, Any_Type); + + elsif not Is_Type (T_Name) + and then T_Name /= Standard_Void_Type + then + Error_Msg_Sloc := Sloc (T_Name); + Error_Msg_N ("subtype mark required in this context", N); + Error_Msg_NE ("\found & declared#", N, T_Name); + Set_Entity (N, Any_Type); + + else + T_Name := Get_Full_View (T_Name); + + if In_Open_Scopes (T_Name) then + if Ekind (Base_Type (T_Name)) = E_Task_Type then + Error_Msg_N ("task type cannot be used as type mark " & + "within its own body", N); + else + Error_Msg_N ("type declaration cannot refer to itself", N); + end if; + + Set_Etype (N, Any_Type); + Set_Entity (N, Any_Type); + Set_Error_Posted (T_Name); + return; + end if; + + Set_Entity (N, T_Name); + Set_Etype (N, T_Name); + end if; + end if; + + if Present (Etype (N)) then + if Is_Fixed_Point_Type (Etype (N)) then + Check_Restriction (No_Fixed_Point, N); + elsif Is_Floating_Point_Type (Etype (N)) then + Check_Restriction (No_Floating_Point, N); + end if; + end if; + end Find_Type; + + ------------------- + -- Get_Full_View -- + ------------------- + + function Get_Full_View (T_Name : Entity_Id) return Entity_Id is + begin + if (Ekind (T_Name) = E_Incomplete_Type + and then Present (Full_View (T_Name))) + then + return Full_View (T_Name); + + elsif Is_Class_Wide_Type (T_Name) + and then Ekind (Root_Type (T_Name)) = E_Incomplete_Type + and then Present (Full_View (Root_Type (T_Name))) + then + return Class_Wide_Type (Full_View (Root_Type (T_Name))); + + else + return T_Name; + end if; + end Get_Full_View; + + ------------------------------------ + -- Has_Implicit_Character_Literal -- + ------------------------------------ + + function Has_Implicit_Character_Literal (N : Node_Id) return Boolean is + Id : Entity_Id; + Found : Boolean := False; + P : constant Entity_Id := Entity (Prefix (N)); + Priv_Id : Entity_Id := Empty; + + begin + if Ekind (P) = E_Package + and then not In_Open_Scopes (P) + then + Priv_Id := First_Private_Entity (P); + end if; + + if P = Standard_Standard then + Change_Selected_Component_To_Expanded_Name (N); + Rewrite (N, Selector_Name (N)); + Analyze (N); + Set_Etype (Original_Node (N), Standard_Character); + return True; + end if; + + Id := First_Entity (P); + + while Present (Id) + and then Id /= Priv_Id + loop + if Is_Character_Type (Id) + and then (Root_Type (Id) = Standard_Character + or else Root_Type (Id) = Standard_Wide_Character) + and then Id = Base_Type (Id) + then + -- We replace the node with the literal itself, resolve as a + -- character, and set the type correctly. + + if not Found then + Change_Selected_Component_To_Expanded_Name (N); + Rewrite (N, Selector_Name (N)); + Analyze (N); + Set_Etype (N, Id); + Set_Etype (Original_Node (N), Id); + Found := True; + + else + -- More than one type derived from Character in given scope. + -- Collect all possible interpretations. + + Add_One_Interp (N, Id, Id); + end if; + end if; + + Next_Entity (Id); + end loop; + + return Found; + end Has_Implicit_Character_Literal; + + --------------------------- + -- Has_Implicit_Operator -- + --------------------------- + + function Has_Implicit_Operator (N : Node_Id) return Boolean is + Op_Id : constant Name_Id := Chars (Selector_Name (N)); + P : constant Entity_Id := Entity (Prefix (N)); + Id : Entity_Id; + Priv_Id : Entity_Id := Empty; + + procedure Add_Implicit_Operator (T : Entity_Id); + -- Add implicit interpretation to node N, using the type for which + -- a predefined operator exists. + + --------------------------- + -- Add_Implicit_Operator -- + --------------------------- + + procedure Add_Implicit_Operator (T : Entity_Id) is + Predef_Op : Entity_Id; + + begin + Predef_Op := Current_Entity (Selector_Name (N)); + + while Present (Predef_Op) + and then Scope (Predef_Op) /= Standard_Standard + loop + Predef_Op := Homonym (Predef_Op); + end loop; + + if Nkind (N) = N_Selected_Component then + Change_Selected_Component_To_Expanded_Name (N); + end if; + + Add_One_Interp (N, Predef_Op, T); + + -- For operators with unary and binary interpretations, add both + + if Present (Homonym (Predef_Op)) then + Add_One_Interp (N, Homonym (Predef_Op), T); + end if; + end Add_Implicit_Operator; + + -- Start of processing for Has_Implicit_Operator + + begin + + if Ekind (P) = E_Package + and then not In_Open_Scopes (P) + then + Priv_Id := First_Private_Entity (P); + end if; + + Id := First_Entity (P); + + case Op_Id is + + -- Boolean operators: an implicit declaration exists if the scope + -- contains a declaration for a derived Boolean type, or for an + -- array of Boolean type. + + when Name_Op_And | Name_Op_Not | Name_Op_Or | Name_Op_Xor => + + while Id /= Priv_Id loop + + if Valid_Boolean_Arg (Id) + and then Id = Base_Type (Id) + then + Add_Implicit_Operator (Id); + return True; + end if; + + Next_Entity (Id); + end loop; + + -- Equality: look for any non-limited type. Result is Boolean. + + when Name_Op_Eq | Name_Op_Ne => + + while Id /= Priv_Id loop + + if Is_Type (Id) + and then not Is_Limited_Type (Id) + and then Id = Base_Type (Id) + then + Add_Implicit_Operator (Standard_Boolean); + return True; + end if; + + Next_Entity (Id); + end loop; + + -- Comparison operators: scalar type, or array of scalar. + + when Name_Op_Lt | Name_Op_Le | Name_Op_Gt | Name_Op_Ge => + + while Id /= Priv_Id loop + if (Is_Scalar_Type (Id) + or else (Is_Array_Type (Id) + and then Is_Scalar_Type (Component_Type (Id)))) + and then Id = Base_Type (Id) + then + Add_Implicit_Operator (Standard_Boolean); + return True; + end if; + + Next_Entity (Id); + end loop; + + -- Arithmetic operators: any numeric type + + when Name_Op_Abs | + Name_Op_Add | + Name_Op_Mod | + Name_Op_Rem | + Name_Op_Subtract | + Name_Op_Multiply | + Name_Op_Divide | + Name_Op_Expon => + + while Id /= Priv_Id loop + if Is_Numeric_Type (Id) + and then Id = Base_Type (Id) + then + Add_Implicit_Operator (Id); + return True; + end if; + + Next_Entity (Id); + end loop; + + -- Concatenation: any one-dimensional array type + + when Name_Op_Concat => + + while Id /= Priv_Id loop + if Is_Array_Type (Id) and then Number_Dimensions (Id) = 1 + and then Id = Base_Type (Id) + then + Add_Implicit_Operator (Id); + return True; + end if; + + Next_Entity (Id); + end loop; + + -- What is the others condition here? Should we be using a + -- subtype of Name_Id that would restrict to operators ??? + + when others => null; + + end case; + + -- If we fall through, then we do not have an implicit operator + + return False; + + end Has_Implicit_Operator; + + -------------------- + -- In_Open_Scopes -- + -------------------- + + function In_Open_Scopes (S : Entity_Id) return Boolean is + begin + -- Since there are several scope stacks maintained by Scope_Stack each + -- delineated by Standard (see comments by definition of Scope_Stack) + -- it is necessary to end the search when Standard is reached. + + for J in reverse 0 .. Scope_Stack.Last loop + if Scope_Stack.Table (J).Entity = S then + return True; + end if; + + -- We need Is_Active_Stack_Base to tell us when to stop rather + -- than checking for Standard_Standard because there are cases + -- where Standard_Standard appears in the middle of the active + -- set of scopes. This affects the declaration and overriding + -- of private inherited operations in instantiations of generic + -- child units. + + exit when Scope_Stack.Table (J).Is_Active_Stack_Base; + end loop; + + return False; + end In_Open_Scopes; + + ----------------------------- + -- Inherit_Renamed_Profile -- + ----------------------------- + + procedure Inherit_Renamed_Profile (New_S : Entity_Id; Old_S : Entity_Id) is + New_F : Entity_Id; + Old_F : Entity_Id; + Old_T : Entity_Id; + New_T : Entity_Id; + + begin + if Ekind (Old_S) = E_Operator then + + New_F := First_Formal (New_S); + + while Present (New_F) loop + Set_Etype (New_F, Base_Type (Etype (New_F))); + Next_Formal (New_F); + end loop; + + Set_Etype (New_S, Base_Type (Etype (New_S))); + + else + New_F := First_Formal (New_S); + Old_F := First_Formal (Old_S); + + while Present (New_F) loop + New_T := Etype (New_F); + Old_T := Etype (Old_F); + + -- If the new type is a renaming of the old one, as is the + -- case for actuals in instances, retain its name, to simplify + -- later disambiguation. + + if Nkind (Parent (New_T)) = N_Subtype_Declaration + and then Is_Entity_Name (Subtype_Indication (Parent (New_T))) + and then Entity (Subtype_Indication (Parent (New_T))) = Old_T + then + null; + else + Set_Etype (New_F, Old_T); + end if; + + Next_Formal (New_F); + Next_Formal (Old_F); + end loop; + + if Ekind (Old_S) = E_Function + or else Ekind (Old_S) = E_Enumeration_Literal + then + Set_Etype (New_S, Etype (Old_S)); + end if; + end if; + end Inherit_Renamed_Profile; + + ---------------- + -- Initialize -- + ---------------- + + procedure Initialize is + begin + Urefs.Init; + end Initialize; + + ------------------------- + -- Install_Use_Clauses -- + ------------------------- + + procedure Install_Use_Clauses (Clause : Node_Id) is + U : Node_Id := Clause; + P : Node_Id; + Id : Entity_Id; + + begin + while Present (U) loop + + -- Case of USE package + + if Nkind (U) = N_Use_Package_Clause then + P := First (Names (U)); + + while Present (P) loop + Id := Entity (P); + + if Ekind (Id) = E_Package then + + if In_Use (Id) then + Set_Redundant_Use (P, True); + + elsif Present (Renamed_Object (Id)) + and then In_Use (Renamed_Object (Id)) + then + Set_Redundant_Use (P, True); + + else + Use_One_Package (Id, U); + end if; + end if; + + Next (P); + end loop; + + -- case of USE TYPE + + else + P := First (Subtype_Marks (U)); + + while Present (P) loop + + if Entity (P) /= Any_Type then + Use_One_Type (P, U); + end if; + + Next (P); + end loop; + end if; + + Next_Use_Clause (U); + end loop; + end Install_Use_Clauses; + + ------------------------------------- + -- Is_Appropriate_For_Entry_Prefix -- + ------------------------------------- + + function Is_Appropriate_For_Entry_Prefix (T : Entity_Id) return Boolean is + P_Type : Entity_Id := T; + + begin + if Is_Access_Type (P_Type) then + P_Type := Designated_Type (P_Type); + end if; + + return Is_Task_Type (P_Type) or else Is_Protected_Type (P_Type); + end Is_Appropriate_For_Entry_Prefix; + + ------------------------------- + -- Is_Appropriate_For_Record -- + ------------------------------- + + function Is_Appropriate_For_Record + (T : Entity_Id) + return Boolean + is + function Has_Components (T1 : Entity_Id) return Boolean; + -- Determine if given type has components (i.e. is either a record + -- type or a type that has discriminants). + + function Has_Components (T1 : Entity_Id) return Boolean is + begin + return Is_Record_Type (T1) + or else (Is_Private_Type (T1) and then Has_Discriminants (T1)) + or else (Is_Task_Type (T1) and then Has_Discriminants (T1)); + end Has_Components; + + -- Start of processing for Is_Appropriate_For_Record + + begin + return + Present (T) + and then (Has_Components (T) + or else (Is_Access_Type (T) + and then + Has_Components (Designated_Type (T)))); + end Is_Appropriate_For_Record; + + --------------- + -- New_Scope -- + --------------- + + procedure New_Scope (S : Entity_Id) is + E : Entity_Id; + + begin + if Ekind (S) = E_Void then + null; + + -- Set scope depth if not a non-concurrent type, and we have not + -- yet set the scope depth. This means that we have the first + -- occurrence of the scope, and this is where the depth is set. + + elsif (not Is_Type (S) or else Is_Concurrent_Type (S)) + and then not Scope_Depth_Set (S) + then + if S = Standard_Standard then + Set_Scope_Depth_Value (S, Uint_0); + + elsif Is_Child_Unit (S) then + Set_Scope_Depth_Value (S, Uint_1); + + elsif not Is_Record_Type (Current_Scope) then + if Ekind (S) = E_Loop then + Set_Scope_Depth_Value (S, Scope_Depth (Current_Scope)); + else + Set_Scope_Depth_Value (S, Scope_Depth (Current_Scope) + 1); + end if; + end if; + end if; + + Scope_Stack.Increment_Last; + + Scope_Stack.Table (Scope_Stack.Last).Entity := S; + + Scope_Stack.Table (Scope_Stack.Last).Save_Scope_Suppress := + Scope_Suppress; + + Scope_Stack.Table (Scope_Stack.Last).Save_Entity_Suppress := + Entity_Suppress.Last; + + if Scope_Stack.Last > Scope_Stack.First then + Scope_Stack.Table (Scope_Stack.Last).Component_Alignment_Default := + Scope_Stack.Table (Scope_Stack.Last - 1).Component_Alignment_Default; + end if; + + Scope_Stack.Table (Scope_Stack.Last).Last_Subprogram_Name := null; + Scope_Stack.Table (Scope_Stack.Last).Is_Transient := False; + Scope_Stack.Table (Scope_Stack.Last).Node_To_Be_Wrapped := Empty; + Scope_Stack.Table (Scope_Stack.Last).Pending_Freeze_Actions := No_List; + Scope_Stack.Table + (Scope_Stack.Last).Actions_To_Be_Wrapped_Before := No_List; + Scope_Stack.Table + (Scope_Stack.Last).Actions_To_Be_Wrapped_After := No_List; + Scope_Stack.Table (Scope_Stack.Last).First_Use_Clause := Empty; + Scope_Stack.Table (Scope_Stack.Last).Is_Active_Stack_Base := False; + + if Debug_Flag_W then + Write_Str ("--> new scope: "); + Write_Name (Chars (Current_Scope)); + Write_Str (", Id="); + Write_Int (Int (Current_Scope)); + Write_Str (", Depth="); + Write_Int (Int (Scope_Stack.Last)); + Write_Eol; + end if; + + -- Copy from Scope (S) the categorization flags to S, this is not + -- done in case Scope (S) is Standard_Standard since propagation + -- is from library unit entity inwards. + + if S /= Standard_Standard + and then Scope (S) /= Standard_Standard + and then not Is_Child_Unit (S) + then + E := Scope (S); + + if Nkind (E) not in N_Entity then + return; + end if; + + -- We only propagate inwards for library level entities, + -- inner level subprograms do not inherit the categorization. + + if Is_Library_Level_Entity (S) then + Set_Is_Pure (S, Is_Pure (E)); + Set_Is_Preelaborated (S, Is_Preelaborated (E)); + Set_Is_Remote_Call_Interface (S, Is_Remote_Call_Interface (E)); + Set_Is_Remote_Types (S, Is_Remote_Types (E)); + Set_Is_Shared_Passive (S, Is_Shared_Passive (E)); + end if; + end if; + end New_Scope; + + --------------- + -- Pop_Scope -- + --------------- + + procedure Pop_Scope is + E : Entity_Id; + + begin + if Debug_Flag_E then + Write_Info; + end if; + + Scope_Suppress := + Scope_Stack.Table (Scope_Stack.Last).Save_Scope_Suppress; + + while Entity_Suppress.Last > + Scope_Stack.Table (Scope_Stack.Last).Save_Entity_Suppress + loop + E := Entity_Suppress.Table (Entity_Suppress.Last).Entity; + + case Entity_Suppress.Table (Entity_Suppress.Last).Check is + + when Access_Check => + Set_Suppress_Access_Checks (E, False); + + when Accessibility_Check => + Set_Suppress_Accessibility_Checks (E, False); + + when Discriminant_Check => + Set_Suppress_Discriminant_Checks (E, False); + + when Division_Check => + Set_Suppress_Division_Checks (E, False); + + when Elaboration_Check => + Set_Suppress_Elaboration_Checks (E, False); + + when Index_Check => + Set_Suppress_Index_Checks (E, False); + + when Length_Check => + Set_Suppress_Length_Checks (E, False); + + when Overflow_Check => + Set_Suppress_Overflow_Checks (E, False); + + when Range_Check => + Set_Suppress_Range_Checks (E, False); + + when Storage_Check => + Set_Suppress_Storage_Checks (E, False); + + when Tag_Check => + Set_Suppress_Tag_Checks (E, False); + + -- All_Checks should not appear here (since it is entered as a + -- series of its separate checks). Bomb if it is encountered + + when All_Checks => + raise Program_Error; + end case; + + Entity_Suppress.Decrement_Last; + end loop; + + if Debug_Flag_W then + Write_Str ("--> exiting scope: "); + Write_Name (Chars (Current_Scope)); + Write_Str (", Depth="); + Write_Int (Int (Scope_Stack.Last)); + Write_Eol; + end if; + + End_Use_Clauses (Scope_Stack.Table (Scope_Stack.Last).First_Use_Clause); + + -- If the actions to be wrapped are still there they will get lost + -- causing incomplete code to be generated. It is better to abort in + -- this case. + + pragma Assert (Scope_Stack.Table + (Scope_Stack.Last).Actions_To_Be_Wrapped_Before = No_List); + + pragma Assert (Scope_Stack.Table + (Scope_Stack.Last).Actions_To_Be_Wrapped_After = No_List); + + -- Free last subprogram name if allocated, and pop scope + + Free (Scope_Stack.Table (Scope_Stack.Last).Last_Subprogram_Name); + Scope_Stack.Decrement_Last; + end Pop_Scope; + + --------------------- + -- Premature_Usage -- + --------------------- + + procedure Premature_Usage (N : Node_Id) is + Kind : Node_Kind := Nkind (Parent (Entity (N))); + E : Entity_Id := Entity (N); + + begin + -- Within an instance, the analysis of the actual for a formal object + -- does not see the name of the object itself. This is significant + -- only if the object is an aggregate, where its analysis does not do + -- any name resolution on component associations. (see 4717-008). In + -- such a case, look for the visible homonym on the chain. + + if In_Instance + and then Present (Homonym (E)) + then + E := Homonym (E); + + while Present (E) + and then not In_Open_Scopes (Scope (E)) + loop + E := Homonym (E); + end loop; + + if Present (E) then + Set_Entity (N, E); + Set_Etype (N, Etype (E)); + return; + end if; + end if; + + if Kind = N_Component_Declaration then + Error_Msg_N + ("component&! cannot be used before end of record declaration", N); + + elsif Kind = N_Parameter_Specification then + Error_Msg_N + ("formal parameter&! cannot be used before end of specification", + N); + + elsif Kind = N_Discriminant_Specification then + Error_Msg_N + ("discriminant&! cannot be used before end of discriminant part", + N); + + elsif Kind = N_Procedure_Specification + or else Kind = N_Function_Specification + then + Error_Msg_N + ("subprogram&! cannot be used before end of its declaration", + N); + else + Error_Msg_N + ("object& cannot be used before end of its declaration!", N); + end if; + end Premature_Usage; + + ------------------------ + -- Present_System_Aux -- + ------------------------ + + function Present_System_Aux (N : Node_Id := Empty) return Boolean is + Loc : Source_Ptr; + Aux_Name : Name_Id; + Unum : Unit_Number_Type; + Withn : Node_Id; + With_Sys : Node_Id; + The_Unit : Node_Id; + + function Find_System (C_Unit : Node_Id) return Entity_Id; + -- Scan context clause of compilation unit to find a with_clause + -- for System. + + function Find_System (C_Unit : Node_Id) return Entity_Id is + With_Clause : Node_Id; + + begin + With_Clause := First (Context_Items (C_Unit)); + + while Present (With_Clause) loop + if (Nkind (With_Clause) = N_With_Clause + and then Chars (Name (With_Clause)) = Name_System) + and then Comes_From_Source (With_Clause) + then + return With_Clause; + end if; + + Next (With_Clause); + end loop; + + return Empty; + end Find_System; + + -- Start of processing for Present_System_Aux + + begin + -- The child unit may have been loaded and analyzed already. + + if Present (System_Aux_Id) then + return True; + + -- If no previous pragma for System.Aux, nothing to load + + elsif No (System_Extend_Pragma_Arg) then + return False; + + -- Use the unit name given in the pragma to retrieve the unit. + -- Verify that System itself appears in the context clause of the + -- current compilation. If System is not present, an error will + -- have been reported already. + + else + With_Sys := Find_System (Cunit (Current_Sem_Unit)); + + The_Unit := Unit (Cunit (Current_Sem_Unit)); + + if No (With_Sys) + and then (Nkind (The_Unit) = N_Package_Body + or else (Nkind (The_Unit) = N_Subprogram_Body + and then not Acts_As_Spec (Cunit (Current_Sem_Unit)))) + then + With_Sys := Find_System (Library_Unit (Cunit (Current_Sem_Unit))); + end if; + + if No (With_Sys) + and then Present (N) + then + -- If we are compiling a subunit, we need to examine its + -- context as well (Current_Sem_Unit is the parent unit); + + The_Unit := Parent (N); + + while Nkind (The_Unit) /= N_Compilation_Unit loop + The_Unit := Parent (The_Unit); + end loop; + + if Nkind (Unit (The_Unit)) = N_Subunit then + With_Sys := Find_System (The_Unit); + end if; + end if; + + if No (With_Sys) then + return False; + end if; + + Loc := Sloc (With_Sys); + Get_Name_String (Chars (Expression (System_Extend_Pragma_Arg))); + Name_Buffer (8 .. Name_Len + 7) := Name_Buffer (1 .. Name_Len); + Name_Buffer (1 .. 7) := "system."; + Name_Buffer (Name_Len + 8) := '%'; + Name_Buffer (Name_Len + 9) := 's'; + Name_Len := Name_Len + 9; + Aux_Name := Name_Find; + + Unum := + Load_Unit + (Load_Name => Aux_Name, + Required => False, + Subunit => False, + Error_Node => With_Sys); + + if Unum /= No_Unit then + Semantics (Cunit (Unum)); + System_Aux_Id := + Defining_Entity (Specification (Unit (Cunit (Unum)))); + + Withn := Make_With_Clause (Loc, + Name => + Make_Expanded_Name (Loc, + Chars => Chars (System_Aux_Id), + Prefix => + New_Reference_To (Scope (System_Aux_Id), Loc), + Selector_Name => + New_Reference_To (System_Aux_Id, Loc))); + + Set_Entity (Name (Withn), System_Aux_Id); + + Set_Library_Unit (Withn, Cunit (Unum)); + Set_Corresponding_Spec (Withn, System_Aux_Id); + Set_First_Name (Withn, True); + Set_Implicit_With (Withn, True); + + Insert_After (With_Sys, Withn); + Mark_Rewrite_Insertion (Withn); + Set_Context_Installed (Withn); + + return True; + + -- Here if unit load failed + + else + Error_Msg_Name_1 := Name_System; + Error_Msg_Name_2 := Chars (Expression (System_Extend_Pragma_Arg)); + Error_Msg_N + ("extension package `%.%` does not exist", + Opt.System_Extend_Pragma_Arg); + return False; + end if; + end if; + end Present_System_Aux; + + ------------------------- + -- Restore_Scope_Stack -- + ------------------------- + + procedure Restore_Scope_Stack is + E : Entity_Id; + S : Entity_Id; + Comp_Unit : Node_Id; + In_Child : Boolean := False; + Full_Vis : Boolean := True; + + begin + -- Restore visibility of previous scope stack, if any. + + for J in reverse 0 .. Scope_Stack.Last loop + exit when Scope_Stack.Table (J).Entity = Standard_Standard + or else No (Scope_Stack.Table (J).Entity); + + S := Scope_Stack.Table (J).Entity; + + if not Is_Hidden_Open_Scope (S) then + + -- If the parent scope is hidden, its entities are hidden as + -- well, unless the entity is the instantiation currently + -- being analyzed. + + if not Is_Hidden_Open_Scope (Scope (S)) + or else not Analyzed (Parent (S)) + or else Scope (S) = Standard_Standard + then + Set_Is_Immediately_Visible (S, True); + end if; + + E := First_Entity (S); + + while Present (E) loop + if Is_Child_Unit (E) then + Set_Is_Immediately_Visible (E, + Is_Visible_Child_Unit (E) or else In_Open_Scopes (E)); + else + Set_Is_Immediately_Visible (E, True); + end if; + + Next_Entity (E); + + if not Full_Vis then + exit when E = First_Private_Entity (S); + end if; + end loop; + + -- The visibility of child units (siblings of current compilation) + -- must be restored in any case. Their declarations may appear + -- after the private part of the parent. + + if not Full_Vis + and then Present (E) + then + while Present (E) loop + if Is_Child_Unit (E) then + Set_Is_Immediately_Visible (E, + Is_Visible_Child_Unit (E) or else In_Open_Scopes (E)); + end if; + + Next_Entity (E); + end loop; + end if; + end if; + + if Is_Child_Unit (S) + and not In_Child -- check only for current unit. + then + In_Child := True; + + -- restore visibility of parents according to whether the child + -- is private and whether we are in its visible part. + + Comp_Unit := Parent (Unit_Declaration_Node (S)); + + if Nkind (Comp_Unit) = N_Compilation_Unit + and then Private_Present (Comp_Unit) + then + Full_Vis := True; + + elsif (Ekind (S) = E_Package + or else Ekind (S) = E_Generic_Package) + and then (In_Private_Part (S) + or else In_Package_Body (S)) + then + Full_Vis := True; + + elsif (Ekind (S) = E_Procedure + or else Ekind (S) = E_Function) + and then Has_Completion (S) + then + Full_Vis := True; + else + Full_Vis := False; + end if; + else + Full_Vis := True; + end if; + end loop; + end Restore_Scope_Stack; + + ---------------------- + -- Save_Scope_Stack -- + ---------------------- + + procedure Save_Scope_Stack is + E : Entity_Id; + S : Entity_Id; + SS_Last : constant Int := Scope_Stack.Last; + + begin + if SS_Last >= Scope_Stack.First + and then Scope_Stack.Table (SS_Last).Entity /= Standard_Standard + then + + -- If the call is from within a compilation unit, as when + -- called from Rtsfind, make current entries in scope stack + -- invisible while we analyze the new unit. + + for J in reverse 0 .. SS_Last loop + exit when Scope_Stack.Table (J).Entity = Standard_Standard + or else No (Scope_Stack.Table (J).Entity); + + S := Scope_Stack.Table (J).Entity; + Set_Is_Immediately_Visible (S, False); + E := First_Entity (S); + + while Present (E) loop + Set_Is_Immediately_Visible (E, False); + Next_Entity (E); + end loop; + end loop; + + end if; + end Save_Scope_Stack; + + ------------- + -- Set_Use -- + ------------- + + procedure Set_Use (L : List_Id) is + Decl : Node_Id; + Pack_Name : Node_Id; + Pack : Entity_Id; + Id : Entity_Id; + + begin + if Present (L) then + Decl := First (L); + + while Present (Decl) loop + if Nkind (Decl) = N_Use_Package_Clause then + Chain_Use_Clause (Decl); + Pack_Name := First (Names (Decl)); + + while Present (Pack_Name) loop + Pack := Entity (Pack_Name); + + if Ekind (Pack) = E_Package + and then Applicable_Use (Pack_Name) + then + Use_One_Package (Pack, Decl); + end if; + + Next (Pack_Name); + end loop; + + elsif Nkind (Decl) = N_Use_Type_Clause then + Chain_Use_Clause (Decl); + Id := First (Subtype_Marks (Decl)); + + while Present (Id) loop + if Entity (Id) /= Any_Type then + Use_One_Type (Id, Decl); + end if; + + Next (Id); + end loop; + end if; + + Next (Decl); + end loop; + end if; + end Set_Use; + + --------------------- + -- Use_One_Package -- + --------------------- + + procedure Use_One_Package (P : Entity_Id; N : Node_Id) is + Id : Entity_Id; + Prev : Entity_Id; + Current_Instance : Entity_Id := Empty; + Real_P : Entity_Id; + + begin + if Ekind (P) /= E_Package then + return; + end if; + + Set_In_Use (P); + + if From_With_Type (P) then + Error_Msg_N ("imported package cannot appear in use clause", N); + end if; + + -- Find enclosing instance, if any. + + if In_Instance then + Current_Instance := Current_Scope; + + while not Is_Generic_Instance (Current_Instance) loop + Current_Instance := Scope (Current_Instance); + end loop; + + if No (Hidden_By_Use_Clause (N)) then + Set_Hidden_By_Use_Clause (N, New_Elmt_List); + end if; + end if; + + -- If unit is a package renaming, indicate that the renamed + -- package is also in use (the flags on both entities must + -- remain consistent, and a subsequent use of either of them + -- should be recognized as redundant). + + if Present (Renamed_Object (P)) then + Set_In_Use (Renamed_Object (P)); + Real_P := Renamed_Object (P); + else + Real_P := P; + end if; + + -- Loop through entities in one package making them potentially + -- use-visible. + + Id := First_Entity (P); + while Present (Id) + and then Id /= First_Private_Entity (P) + loop + Prev := Current_Entity (Id); + + while Present (Prev) loop + if Is_Immediately_Visible (Prev) + and then (not Is_Overloadable (Prev) + or else not Is_Overloadable (Id) + or else (Type_Conformant (Id, Prev))) + then + if No (Current_Instance) then + + -- Potentially use-visible entity remains hidden + + goto Next_Usable_Entity; + + -- A use clause within an instance hides outer global + -- entities, which are not used to resolve local entities + -- in the instance. Note that the predefined entities in + -- Standard could not have been hidden in the generic by + -- a use clause, and therefore remain visible. Other + -- compilation units whose entities appear in Standard must + -- be hidden in an instance. + + -- To determine whether an entity is external to the instance + -- we compare the scope depth of its scope with that of the + -- current instance. However, a generic actual of a subprogram + -- instance is declared in the wrapper package but will not be + -- hidden by a use-visible entity. + + elsif not Is_Hidden (Id) + and then not Is_Wrapper_Package (Scope (Prev)) + and then Scope_Depth (Scope (Prev)) < + Scope_Depth (Current_Instance) + and then (Scope (Prev) /= Standard_Standard + or else Sloc (Prev) > Standard_Location) + then + Set_Is_Potentially_Use_Visible (Id); + Set_Is_Immediately_Visible (Prev, False); + Append_Elmt (Prev, Hidden_By_Use_Clause (N)); + end if; + + -- A user-defined operator is not use-visible if the + -- predefined operator for the type is immediately visible, + -- which is the case if the type of the operand is in an open + -- scope. This does not apply to user-defined operators that + -- have operands of different types, because the predefined + -- mixed mode operations (multiplication and division) apply to + -- universal types and do not hide anything. + + elsif Ekind (Prev) = E_Operator + and then Operator_Matches_Spec (Prev, Id) + and then In_Open_Scopes + (Scope (Base_Type (Etype (First_Formal (Id))))) + and then (No (Next_Formal (First_Formal (Id))) + or else Etype (First_Formal (Id)) + = Etype (Next_Formal (First_Formal (Id))) + or else Chars (Prev) = Name_Op_Expon) + then + goto Next_Usable_Entity; + end if; + + Prev := Homonym (Prev); + end loop; + + -- On exit, we know entity is not hidden, unless it is private. + + if not Is_Hidden (Id) + and then ((not Is_Child_Unit (Id)) + or else Is_Visible_Child_Unit (Id)) + then + Set_Is_Potentially_Use_Visible (Id); + + if Is_Private_Type (Id) + and then Present (Full_View (Id)) + then + Set_Is_Potentially_Use_Visible (Full_View (Id)); + end if; + end if; + + <<Next_Usable_Entity>> + Next_Entity (Id); + end loop; + + -- Child units are also made use-visible by a use clause, but they + -- may appear after all visible declarations in the parent entity list. + + while Present (Id) loop + + if Is_Child_Unit (Id) + and then Is_Visible_Child_Unit (Id) + then + Set_Is_Potentially_Use_Visible (Id); + end if; + + Next_Entity (Id); + end loop; + + if Chars (Real_P) = Name_System + and then Scope (Real_P) = Standard_Standard + and then Present_System_Aux (N) + then + Use_One_Package (System_Aux_Id, N); + end if; + + end Use_One_Package; + + ------------------ + -- Use_One_Type -- + ------------------ + + procedure Use_One_Type (Id : Node_Id; N : Node_Id) is + T : Entity_Id; + Op_List : Elist_Id; + Elmt : Elmt_Id; + + begin + -- It is the type determined by the subtype mark (8.4(8)) whose + -- operations become potentially use-visible. + + T := Base_Type (Entity (Id)); + + -- Save current visibility status of type, before setting. + + Set_Redundant_Use + (Id, In_Use (T) or else Is_Potentially_Use_Visible (T)); + + if In_Open_Scopes (Scope (T)) then + null; + + elsif not Redundant_Use (Id) then + Set_In_Use (T); + Op_List := Collect_Primitive_Operations (T); + Elmt := First_Elmt (Op_List); + + while Present (Elmt) loop + + if (Nkind (Node (Elmt)) = N_Defining_Operator_Symbol + or else Chars (Node (Elmt)) in Any_Operator_Name) + and then not Is_Hidden (Node (Elmt)) + then + Set_Is_Potentially_Use_Visible (Node (Elmt)); + end if; + + Next_Elmt (Elmt); + end loop; + end if; + + end Use_One_Type; + + ---------------- + -- Write_Info -- + ---------------- + + procedure Write_Info is + Id : Entity_Id := First_Entity (Current_Scope); + + begin + -- No point in dumping standard entities + + if Current_Scope = Standard_Standard then + return; + end if; + + Write_Str ("========================================================"); + Write_Eol; + Write_Str (" Defined Entities in "); + Write_Name (Chars (Current_Scope)); + Write_Eol; + Write_Str ("========================================================"); + Write_Eol; + + if No (Id) then + Write_Str ("-- none --"); + Write_Eol; + + else + while Present (Id) loop + Write_Entity_Info (Id, " "); + Next_Entity (Id); + end loop; + end if; + + if Scope (Current_Scope) = Standard_Standard then + + -- Print information on the current unit itself + + Write_Entity_Info (Current_Scope, " "); + end if; + + Write_Eol; + end Write_Info; + + ----------------- + -- Write_Scopes -- + ----------------- + + procedure Write_Scopes is + S : Entity_Id; + + begin + for J in reverse 1 .. Scope_Stack.Last loop + S := Scope_Stack.Table (J).Entity; + Write_Int (Int (S)); + Write_Str (" === "); + Write_Name (Chars (S)); + Write_Eol; + end loop; + end Write_Scopes; + +end Sem_Ch8; |