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+------------------------------------------------------------------------------
+-- --
+-- GNAT COMPILER COMPONENTS --
+-- --
+-- P A R --
+-- --
+-- B o d y --
+-- --
+-- Copyright (C) 1992-2012, Free Software Foundation, Inc. --
+-- --
+-- GNAT is free software; you can redistribute it and/or modify it under --
+-- terms of the GNU General Public License as published by the Free Soft- --
+-- ware Foundation; either version 3, or (at your option) any later ver- --
+-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
+-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
+-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
+-- for more details. You should have received a copy of the GNU General --
+-- Public License distributed with GNAT; see file COPYING3. If not, go to --
+-- http://www.gnu.org/licenses for a complete copy of the license. --
+-- --
+-- GNAT was originally developed by the GNAT team at New York University. --
+-- Extensive contributions were provided by Ada Core Technologies Inc. --
+-- --
+------------------------------------------------------------------------------
+
+with Aspects; use Aspects;
+with Atree; use Atree;
+with Casing; use Casing;
+with Debug; use Debug;
+with Elists; use Elists;
+with Errout; use Errout;
+with Fname; use Fname;
+with Lib; use Lib;
+with Namet; use Namet;
+with Namet.Sp; use Namet.Sp;
+with Nlists; use Nlists;
+with Nmake; use Nmake;
+with Opt; use Opt;
+with Output; use Output;
+with Par_SCO; use Par_SCO;
+with Restrict; use Restrict;
+with Scans; use Scans;
+with Scn; use Scn;
+with Sem_Util; use Sem_Util;
+with Sinput; use Sinput;
+with Sinput.L; use Sinput.L;
+with Sinfo; use Sinfo;
+with Snames; use Snames;
+with Style;
+with Stylesw; use Stylesw;
+with Table;
+with Tbuild; use Tbuild;
+
+---------
+-- Par --
+---------
+
+function Par (Configuration_Pragmas : Boolean) return List_Id is
+
+ Num_Library_Units : Natural := 0;
+ -- Count number of units parsed (relevant only in syntax check only mode,
+ -- since in semantics check mode only a single unit is permitted anyway).
+
+ Save_Config_Switches : Config_Switches_Type;
+ -- Variable used to save values of config switches while we parse the
+ -- new unit, to be restored on exit for proper recursive behavior.
+
+ Loop_Block_Count : Nat := 0;
+ -- Counter used for constructing loop/block names (see the routine
+ -- Par.Ch5.Get_Loop_Block_Name).
+
+ Inside_Record_Definition : Boolean := False;
+ -- Flag set True within a record definition. Used to control warning
+ -- for redefinition of standard entities (not issued for field names).
+
+ --------------------
+ -- Error Recovery --
+ --------------------
+
+ -- When an error is encountered, a call is made to one of the Error_Msg
+ -- routines to record the error. If the syntax scan is not derailed by the
+ -- error (e.g. a complaint that logical operators are inconsistent in an
+ -- EXPRESSION), then control returns from the Error_Msg call, and the
+ -- parse continues unimpeded.
+
+ -- If on the other hand, the Error_Msg represents a situation from which
+ -- the parser cannot recover locally, the exception Error_Resync is raised
+ -- immediately after the call to Error_Msg. Handlers for Error_Resync
+ -- are located at strategic points to resynchronize the parse. For example,
+ -- when an error occurs in a statement, the handler skips to the next
+ -- semicolon and continues the scan from there.
+
+ -- Each parsing procedure contains a note with the heading "Error recovery"
+ -- which shows if it can propagate the Error_Resync exception. In order
+ -- not to propagate the exception, a procedure must either contain its own
+ -- handler for this exception, or it must not call any other routines which
+ -- propagate the exception.
+
+ -- Note: the arrangement of Error_Resync handlers is such that it should
+ -- never be possible to transfer control through a procedure which made
+ -- an entry in the scope stack, invalidating the contents of the stack.
+
+ Error_Resync : exception;
+ -- Exception raised on error that is not handled locally, see above
+
+ Last_Resync_Point : Source_Ptr;
+ -- The resynchronization routines in Par.Sync run a risk of getting
+ -- stuck in an infinite loop if they do not skip a token, and the caller
+ -- keeps repeating the same resync call. On the other hand, if they skip
+ -- a token unconditionally, some recovery opportunities are missed. The
+ -- variable Last_Resync_Point records the token location previously set
+ -- by a Resync call, and if a subsequent Resync call occurs at the same
+ -- location, then the Resync routine does guarantee to skip a token.
+
+ --------------------------------------------
+ -- Handling Semicolon Used in Place of IS --
+ --------------------------------------------
+
+ -- The following global variables are used in handling the error situation
+ -- of using a semicolon in place of IS in a subprogram declaration as in:
+
+ -- procedure X (Y : Integer);
+ -- Q : Integer;
+ -- begin
+ -- ...
+ -- end;
+
+ -- The two contexts in which this can appear are at the outer level, and
+ -- within a declarative region. At the outer level, we know something is
+ -- wrong as soon as we see the Q (or begin, if there are no declarations),
+ -- and we can immediately decide that the semicolon should have been IS.
+
+ -- The situation in a declarative region is more complex. The declaration
+ -- of Q could belong to the outer region, and we do not know that we have
+ -- an error until we hit the begin. It is still not clear at this point
+ -- from a syntactic point of view that something is wrong, because the
+ -- begin could belong to the enclosing subprogram or package. However, we
+ -- can incorporate a bit of semantic knowledge and note that the body of
+ -- X is missing, so we definitely DO have an error. We diagnose this error
+ -- as semicolon in place of IS on the subprogram line.
+
+ -- There are two styles for this diagnostic. If the begin immediately
+ -- follows the semicolon, then we can place a flag (IS expected) right
+ -- on the semicolon. Otherwise we do not detect the error until we hit
+ -- the begin which refers back to the line with the semicolon.
+
+ -- To control the process in the second case, the following global
+ -- variables are set to indicate that we have a subprogram declaration
+ -- whose body is required and has not yet been found. The prefix SIS
+ -- stands for "Subprogram IS" handling.
+
+ SIS_Entry_Active : Boolean := False;
+ -- Set True to indicate that an entry is active (i.e. that a subprogram
+ -- declaration has been encountered, and no body for this subprogram has
+ -- been encountered). The remaining fields are valid only if this is True.
+
+ SIS_Labl : Node_Id;
+ -- Subprogram designator
+
+ SIS_Sloc : Source_Ptr;
+ -- Source location of FUNCTION/PROCEDURE keyword
+
+ SIS_Ecol : Column_Number;
+ -- Column number of FUNCTION/PROCEDURE keyword
+
+ SIS_Semicolon_Sloc : Source_Ptr;
+ -- Source location of semicolon at end of subprogram declaration
+
+ SIS_Declaration_Node : Node_Id;
+ -- Pointer to tree node for subprogram declaration
+
+ SIS_Missing_Semicolon_Message : Error_Msg_Id;
+ -- Used to save message ID of missing semicolon message (which will be
+ -- modified to missing IS if necessary). Set to No_Error_Msg in the
+ -- normal (non-error) case.
+
+ -- Five things can happen to an active SIS entry
+
+ -- 1. If a BEGIN is encountered with an SIS entry active, then we have
+ -- exactly the situation in which we know the body of the subprogram is
+ -- missing. After posting an error message, we change the spec to a body,
+ -- rechaining the declarations that intervened between the spec and BEGIN.
+
+ -- 2. Another subprogram declaration or body is encountered. In this
+ -- case the entry gets overwritten with the information for the new
+ -- subprogram declaration. We don't catch some nested cases this way,
+ -- but it doesn't seem worth the effort.
+
+ -- 3. A nested declarative region (e.g. package declaration or package
+ -- body) is encountered. The SIS active indication is reset at the start
+ -- of such a nested region. Again, like case 2, this causes us to miss
+ -- some nested cases, but it doesn't seen worth the effort to stack and
+ -- unstack the SIS information. Maybe we will reconsider this if we ever
+ -- get a complaint about a missed case.
+
+ -- 4. We encounter a valid pragma INTERFACE or IMPORT that effectively
+ -- supplies the missing body. In this case we reset the entry.
+
+ -- 5. We encounter the end of the declarative region without encountering
+ -- a BEGIN first. In this situation we simply reset the entry. We know
+ -- that there is a missing body, but it seems more reasonable to let the
+ -- later semantic checking discover this.
+
+ ----------------------------------------------------
+ -- Handling of Reserved Words Used as Identifiers --
+ ----------------------------------------------------
+
+ -- Note: throughout the parser, the terms reserved word and keyword are
+ -- used interchangeably to refer to the same set of reserved keywords
+ -- (including until, protected, etc).
+
+ -- If a reserved word is used in place of an identifier, the parser where
+ -- possible tries to recover gracefully. In particular, if the keyword is
+ -- clearly spelled using identifier casing, e.g. Until in a source program
+ -- using mixed case identifiers and lower case keywords, then the keyword
+ -- is treated as an identifier if it appears in a place where an identifier
+ -- is required.
+
+ -- The situation is more complex if the keyword is spelled with normal
+ -- keyword casing. In this case, the parser is more reluctant to consider
+ -- it to be intended as an identifier, unless it has some further
+ -- confirmation.
+
+ -- In the case of an identifier appearing in the identifier list of a
+ -- declaration, the appearance of a comma or colon right after the keyword
+ -- on the same line is taken as confirmation. For an enumeration literal,
+ -- a comma or right paren right after the identifier is also treated as
+ -- adequate confirmation.
+
+ -- The following type is used in calls to Is_Reserved_Identifier and
+ -- also to P_Defining_Identifier and P_Identifier. The default for all
+ -- these functions is that reserved words in reserved word case are not
+ -- considered to be reserved identifiers. The Id_Check value indicates
+ -- tokens, which if they appear immediately after the identifier, are
+ -- taken as confirming that the use of an identifier was expected
+
+ type Id_Check is
+ (None,
+ -- Default, no special token test
+
+ C_Comma_Right_Paren,
+ -- Consider as identifier if followed by comma or right paren
+
+ C_Comma_Colon,
+ -- Consider as identifier if followed by comma or colon
+
+ C_Do,
+ -- Consider as identifier if followed by DO
+
+ C_Dot,
+ -- Consider as identifier if followed by period
+
+ C_Greater_Greater,
+ -- Consider as identifier if followed by >>
+
+ C_In,
+ -- Consider as identifier if followed by IN
+
+ C_Is,
+ -- Consider as identifier if followed by IS
+
+ C_Left_Paren_Semicolon,
+ -- Consider as identifier if followed by left paren or semicolon
+
+ C_Use,
+ -- Consider as identifier if followed by USE
+
+ C_Vertical_Bar_Arrow);
+ -- Consider as identifier if followed by | or =>
+
+ --------------------------------------------
+ -- Handling IS Used in Place of Semicolon --
+ --------------------------------------------
+
+ -- This is a somewhat trickier situation, and we can't catch it in all
+ -- cases, but we do our best to detect common situations resulting from
+ -- a "cut and paste" operation which forgets to change the IS to semicolon.
+ -- Consider the following example:
+
+ -- package body X is
+ -- procedure A;
+ -- procedure B is
+ -- procedure C;
+ -- ...
+ -- procedure D is
+ -- begin
+ -- ...
+ -- end;
+ -- begin
+ -- ...
+ -- end;
+
+ -- The trouble is that the section of text from PROCEDURE B through END;
+ -- constitutes a valid procedure body, and the danger is that we find out
+ -- far too late that something is wrong (indeed most compilers will behave
+ -- uncomfortably on the above example).
+
+ -- We have two approaches to helping to control this situation. First we
+ -- make every attempt to avoid swallowing the last END; if we can be sure
+ -- that some error will result from doing so. In particular, we won't
+ -- accept the END; unless it is exactly correct (in particular it must not
+ -- have incorrect name tokens), and we won't accept it if it is immediately
+ -- followed by end of file, WITH or SEPARATE (all tokens that unmistakeably
+ -- signal the start of a compilation unit, and which therefore allow us to
+ -- reserve the END; for the outer level.) For more details on this aspect
+ -- of the handling, see package Par.Endh.
+
+ -- If we can avoid eating up the END; then the result in the absence of
+ -- any additional steps would be to post a missing END referring back to
+ -- the subprogram with the bogus IS. Similarly, if the enclosing package
+ -- has no BEGIN, then the result is a missing BEGIN message, which again
+ -- refers back to the subprogram header.
+
+ -- Such an error message is not too bad (it's already a big improvement
+ -- over what many parsers do), but it's not ideal, because the declarations
+ -- following the IS have been absorbed into the wrong scope. In the above
+ -- case, this could result for example in a bogus complaint that the body
+ -- of D was missing from the package.
+
+ -- To catch at least some of these cases, we take the following additional
+ -- steps. First, a subprogram body is marked as having a suspicious IS if
+ -- the declaration line is followed by a line which starts with a symbol
+ -- that can start a declaration in the same column, or to the left of the
+ -- column in which the FUNCTION or PROCEDURE starts (normal style is to
+ -- indent any declarations which really belong a subprogram). If such a
+ -- subprogram encounters a missing BEGIN or missing END, then we decide
+ -- that the IS should have been a semicolon, and the subprogram body node
+ -- is marked (by setting the Bad_Is_Detected flag true. Note that we do
+ -- not do this for library level procedures, only for nested procedures,
+ -- since for library level procedures, we must have a body.
+
+ -- The processing for a declarative part checks to see if the last
+ -- declaration scanned is marked in this way, and if it is, the tree
+ -- is modified to reflect the IS being interpreted as a semicolon.
+
+ ---------------------------------------------------
+ -- Parser Type Definitions and Control Variables --
+ ---------------------------------------------------
+
+ -- The following variable and associated type declaration are used by the
+ -- expression parsing routines to return more detailed information about
+ -- the categorization of a parsed expression.
+
+ type Expr_Form_Type is (
+ EF_Simple_Name, -- Simple name, i.e. possibly qualified identifier
+ EF_Name, -- Simple expression which could also be a name
+ EF_Simple, -- Simple expression which is not call or name
+ EF_Range_Attr, -- Range attribute reference
+ EF_Non_Simple); -- Expression that is not a simple expression
+
+ Expr_Form : Expr_Form_Type;
+
+ -- The following type is used for calls to P_Subprogram, P_Package, P_Task,
+ -- P_Protected to indicate which of several possibilities is acceptable.
+
+ type Pf_Rec is record
+ Spcn : Boolean; -- True if specification OK
+ Decl : Boolean; -- True if declaration OK
+ Gins : Boolean; -- True if generic instantiation OK
+ Pbod : Boolean; -- True if proper body OK
+ Rnam : Boolean; -- True if renaming declaration OK
+ Stub : Boolean; -- True if body stub OK
+ Pexp : Boolean; -- True if parametrized expression OK
+ Fil2 : Boolean; -- Filler to fill to 8 bits
+ end record;
+ pragma Pack (Pf_Rec);
+
+ function T return Boolean renames True;
+ function F return Boolean renames False;
+
+ Pf_Decl_Gins_Pbod_Rnam_Stub_Pexp : constant Pf_Rec :=
+ Pf_Rec'(F, T, T, T, T, T, T, F);
+ Pf_Decl_Pexp : constant Pf_Rec :=
+ Pf_Rec'(F, T, F, F, F, F, T, F);
+ Pf_Decl_Gins_Pbod_Rnam_Pexp : constant Pf_Rec :=
+ Pf_Rec'(F, T, T, T, T, F, T, F);
+ Pf_Decl_Pbod_Pexp : constant Pf_Rec :=
+ Pf_Rec'(F, T, F, T, F, F, T, F);
+ Pf_Pbod_Pexp : constant Pf_Rec :=
+ Pf_Rec'(F, F, F, T, F, F, T, F);
+ Pf_Spcn : constant Pf_Rec :=
+ Pf_Rec'(T, F, F, F, F, F, F, F);
+ -- The above are the only allowed values of Pf_Rec arguments
+
+ type SS_Rec is record
+ Eftm : Boolean; -- ELSIF can terminate sequence
+ Eltm : Boolean; -- ELSE can terminate sequence
+ Extm : Boolean; -- EXCEPTION can terminate sequence
+ Ortm : Boolean; -- OR can terminate sequence
+ Sreq : Boolean; -- at least one statement required
+ Tatm : Boolean; -- THEN ABORT can terminate sequence
+ Whtm : Boolean; -- WHEN can terminate sequence
+ Unco : Boolean; -- Unconditional terminate after one statement
+ end record;
+ pragma Pack (SS_Rec);
+
+ SS_Eftm_Eltm_Sreq : constant SS_Rec := SS_Rec'(T, T, F, F, T, F, F, F);
+ SS_Eltm_Ortm_Tatm : constant SS_Rec := SS_Rec'(F, T, F, T, F, T, F, F);
+ SS_Extm_Sreq : constant SS_Rec := SS_Rec'(F, F, T, F, T, F, F, F);
+ SS_None : constant SS_Rec := SS_Rec'(F, F, F, F, F, F, F, F);
+ SS_Ortm_Sreq : constant SS_Rec := SS_Rec'(F, F, F, T, T, F, F, F);
+ SS_Sreq : constant SS_Rec := SS_Rec'(F, F, F, F, T, F, F, F);
+ SS_Sreq_Whtm : constant SS_Rec := SS_Rec'(F, F, F, F, T, F, T, F);
+ SS_Whtm : constant SS_Rec := SS_Rec'(F, F, F, F, F, F, T, F);
+ SS_Unco : constant SS_Rec := SS_Rec'(F, F, F, F, F, F, F, T);
+
+ Goto_List : Elist_Id;
+ -- List of goto nodes appearing in the current compilation. Used to
+ -- recognize natural loops and convert them into bona fide loops for
+ -- optimization purposes.
+
+ Label_List : Elist_Id;
+ -- List of label nodes for labels appearing in the current compilation.
+ -- Used by Par.Labl to construct the corresponding implicit declarations.
+
+ -----------------
+ -- Scope Table --
+ -----------------
+
+ -- The scope table, also referred to as the scope stack, is used to record
+ -- the current scope context. It is organized as a stack, with inner nested
+ -- entries corresponding to higher entries on the stack. An entry is made
+ -- when the parser encounters the opening of a nested construct (such as a
+ -- record, task, package etc.), and then package Par.Endh uses this stack
+ -- to deal with END lines (including properly dealing with END nesting
+ -- errors).
+
+ type SS_End_Type is
+ -- Type of end entry required for this scope. The last two entries are
+ -- used only in the subprogram body case to mark the case of a suspicious
+ -- IS, or a bad IS (i.e. suspicions confirmed by missing BEGIN or END).
+ -- See separate section on dealing with IS used in place of semicolon.
+ -- Note that for many purposes E_Name, E_Suspicious_Is and E_Bad_Is are
+ -- treated the same (E_Suspicious_Is and E_Bad_Is are simply special cases
+ -- of E_Name). They are placed at the end of the enumeration so that a
+ -- test for >= E_Name catches all three cases efficiently.
+
+ (E_Dummy, -- dummy entry at outer level
+ E_Case, -- END CASE;
+ E_If, -- END IF;
+ E_Loop, -- END LOOP;
+ E_Record, -- END RECORD;
+ E_Return, -- END RETURN;
+ E_Select, -- END SELECT;
+ E_Name, -- END [name];
+ E_Suspicious_Is, -- END [name]; (case of suspicious IS)
+ E_Bad_Is); -- END [name]; (case of bad IS)
+
+ -- The following describes a single entry in the scope table
+
+ type Scope_Table_Entry is record
+ Etyp : SS_End_Type;
+ -- Type of end entry, as per above description
+
+ Lreq : Boolean;
+ -- A flag indicating whether the label, if present, is required to
+ -- appear on the end line. It is referenced only in the case of Etyp is
+ -- equal to E_Name or E_Suspicious_Is where the name may or may not be
+ -- required (yes for labeled block, no in other cases). Note that for
+ -- all cases except begin, the question of whether a label is required
+ -- can be determined from the other fields (for loop, it is required if
+ -- it is present, and for the other constructs it is never required or
+ -- allowed).
+
+ Ecol : Column_Number;
+ -- Contains the absolute column number (with tabs expanded) of the
+ -- expected column of the end assuming normal Ada indentation usage. If
+ -- the RM_Column_Check mode is set, this value is used for generating
+ -- error messages about indentation. Otherwise it is used only to
+ -- control heuristic error recovery actions.
+
+ Labl : Node_Id;
+ -- This field is used to provide the name of the construct being parsed
+ -- and indirectly its kind. For loops and blocks, the field contains the
+ -- source name or the generated one. For package specifications, bodies,
+ -- subprogram specifications and bodies the field holds the correponding
+ -- program unit name. For task declarations and bodies, protected types
+ -- and bodies, and accept statements the field hold the name of the type
+ -- or operation. For if-statements, case-statements, and selects, the
+ -- field is initialized to Error.
+
+ -- Note: this is a bit of an odd (mis)use of Error, since there is no
+ -- Error, but we use this value as a place holder to indicate that it
+ -- is an error to have a label on the end line.
+
+ -- Whenever the field is a name, it is attached to the parent node of
+ -- the construct being parsed. Thus the parent node indicates the kind
+ -- of construct whose parse tree is being built. This is used in error
+ -- recovery.
+
+ Decl : List_Id;
+ -- Points to the list of declarations (i.e. the declarative part)
+ -- associated with this construct. It is set only in the END [name]
+ -- cases, and is set to No_List for all other cases which do not have a
+ -- declarative unit associated with them. This is used for determining
+ -- the proper location for implicit label declarations.
+
+ Node : Node_Id;
+ -- Empty except in the case of entries for IF and CASE statements, in
+ -- which case it contains the N_If_Statement or N_Case_Statement node.
+ -- This is used for setting the End_Span field.
+
+ Sloc : Source_Ptr;
+ -- Source location of the opening token of the construct. This is used
+ -- to refer back to this line in error messages (such as missing or
+ -- incorrect end lines). The Sloc field is not used, and is not set, if
+ -- a label is present (the Labl field provides the text name of the
+ -- label in this case, which is fine for error messages).
+
+ S_Is : Source_Ptr;
+ -- S_Is is relevant only if Etyp is set to E_Suspicious_Is or E_Bad_Is.
+ -- It records the location of the IS that is considered to be
+ -- suspicious.
+
+ Junk : Boolean;
+ -- A boolean flag that is set true if the opening entry is the dubious
+ -- result of some prior error, e.g. a record entry where the record
+ -- keyword was missing. It is used to suppress the issuing of a
+ -- corresponding junk complaint about the end line (we do not want
+ -- to complain about a missing end record when there was no record).
+ end record;
+
+ -- The following declares the scope table itself. The Last field is the
+ -- stack pointer, so that Scope.Table (Scope.Last) is the top entry. The
+ -- oldest entry, at Scope_Stack (0), is a dummy entry with Etyp set to
+ -- E_Dummy, and the other fields undefined. This dummy entry ensures that
+ -- Scope_Stack (Scope_Stack_Ptr).Etyp can always be tested, and that the
+ -- scope stack pointer is always in range.
+
+ package Scope is new Table.Table (
+ Table_Component_Type => Scope_Table_Entry,
+ Table_Index_Type => Int,
+ Table_Low_Bound => 0,
+ Table_Initial => 50,
+ Table_Increment => 100,
+ Table_Name => "Scope");
+
+ ---------------------------------
+ -- Parsing Routines by Chapter --
+ ---------------------------------
+
+ -- Uncommented declarations in this section simply parse the construct
+ -- corresponding to their name, and return an ID value for the Node or
+ -- List that is created.
+
+ -------------
+ -- Par.Ch2 --
+ -------------
+
+ package Ch2 is
+ function P_Pragma (Skipping : Boolean := False) return Node_Id;
+ -- Scan out a pragma. If Skipping is True, then the caller is skipping
+ -- the pragma in the context of illegal placement (this is used to avoid
+ -- some junk cascaded messages).
+
+ function P_Identifier (C : Id_Check := None) return Node_Id;
+ -- Scans out an identifier. The parameter C determines the treatment
+ -- of reserved identifiers. See declaration of Id_Check for details.
+
+ function P_Pragmas_Opt return List_Id;
+ -- This function scans for a sequence of pragmas in other than a
+ -- declaration sequence or statement sequence context. All pragmas
+ -- can appear except pragmas Assert and Debug, which are only allowed
+ -- in a declaration or statement sequence context.
+
+ procedure P_Pragmas_Misplaced;
+ -- Skips misplaced pragmas with a complaint
+
+ procedure P_Pragmas_Opt (List : List_Id);
+ -- Parses optional pragmas and appends them to the List
+ end Ch2;
+
+ -------------
+ -- Par.Ch3 --
+ -------------
+
+ package Ch3 is
+ Missing_Begin_Msg : Error_Msg_Id;
+ -- This variable is set by a call to P_Declarative_Part. Normally it
+ -- is set to No_Error_Msg, indicating that no special processing is
+ -- required by the caller. The special case arises when a statement
+ -- is found in the sequence of declarations. In this case the Id of
+ -- the message issued ("declaration expected") is preserved in this
+ -- variable, then the caller can change it to an appropriate missing
+ -- begin message if indeed the BEGIN is missing.
+
+ function P_Array_Type_Definition return Node_Id;
+ function P_Basic_Declarative_Items return List_Id;
+ function P_Constraint_Opt return Node_Id;
+ function P_Declarative_Part return List_Id;
+ function P_Discrete_Choice_List return List_Id;
+ function P_Discrete_Range return Node_Id;
+ function P_Discrete_Subtype_Definition return Node_Id;
+ function P_Known_Discriminant_Part_Opt return List_Id;
+ function P_Signed_Integer_Type_Definition return Node_Id;
+ function P_Range return Node_Id;
+ function P_Range_Constraint return Node_Id;
+ function P_Record_Definition return Node_Id;
+ function P_Subtype_Mark return Node_Id;
+ function P_Subtype_Mark_Resync return Node_Id;
+ function P_Unknown_Discriminant_Part_Opt return Boolean;
+
+ function P_Access_Definition
+ (Null_Exclusion_Present : Boolean) return Node_Id;
+ -- Ada 2005 (AI-231/AI-254): The caller parses the null-exclusion part
+ -- and indicates if it was present
+
+ function P_Access_Type_Definition
+ (Header_Already_Parsed : Boolean := False) return Node_Id;
+ -- Ada 2005 (AI-254): The formal is used to indicate if the caller has
+ -- parsed the null_exclusion part. In this case the caller has also
+ -- removed the ACCESS token
+
+ procedure P_Component_Items (Decls : List_Id);
+ -- Scan out one or more component items and append them to the given
+ -- list. Only scans out more than one declaration in the case where the
+ -- source has a single declaration with multiple defining identifiers.
+
+ function P_Defining_Identifier (C : Id_Check := None) return Node_Id;
+ -- Scan out a defining identifier. The parameter C controls the
+ -- treatment of errors in case a reserved word is scanned. See the
+ -- declaration of this type for details.
+
+ function P_Interface_Type_Definition
+ (Abstract_Present : Boolean) return Node_Id;
+ -- Ada 2005 (AI-251): Parse the interface type definition part. Abstract
+ -- Present indicates if the reserved word "abstract" has been previously
+ -- found. It is used to report an error message because interface types
+ -- are by definition abstract tagged. We generate a record_definition
+ -- node if the list of interfaces is empty; otherwise we generate a
+ -- derived_type_definition node (the first interface in this list is the
+ -- ancestor interface).
+
+ function P_Null_Exclusion
+ (Allow_Anonymous_In_95 : Boolean := False) return Boolean;
+ -- Ada 2005 (AI-231): Parse the null-excluding part. A True result
+ -- indicates that the null-excluding part was present.
+ --
+ -- Allow_Anonymous_In_95 is True if we are in a context that allows
+ -- anonymous access types in Ada 95, in which case "not null" is legal
+ -- if it precedes "access".
+
+ function P_Subtype_Indication
+ (Not_Null_Present : Boolean := False) return Node_Id;
+ -- Ada 2005 (AI-231): The flag Not_Null_Present indicates that the
+ -- null-excluding part has been scanned out and it was present.
+
+ function P_Range_Or_Subtype_Mark
+ (Allow_Simple_Expression : Boolean := False) return Node_Id;
+ -- Scans out a range or subtype mark, and also permits a general simple
+ -- expression if Allow_Simple_Expression is set to True.
+
+ function Init_Expr_Opt (P : Boolean := False) return Node_Id;
+ -- If an initialization expression is present (:= expression), then
+ -- it is scanned out and returned, otherwise Empty is returned if no
+ -- initialization expression is present. This procedure also handles
+ -- certain common error cases cleanly. The parameter P indicates if
+ -- a right paren can follow the expression (default = no right paren
+ -- allowed).
+
+ procedure Skip_Declaration (S : List_Id);
+ -- Used when scanning statements to skip past a misplaced declaration
+ -- The declaration is scanned out and appended to the given list.
+ -- Token is known to be a declaration token (in Token_Class_Declk)
+ -- on entry, so there definition is a declaration to be scanned.
+
+ function P_Subtype_Indication
+ (Subtype_Mark : Node_Id;
+ Not_Null_Present : Boolean := False) return Node_Id;
+ -- This version of P_Subtype_Indication is called when the caller has
+ -- already scanned out the subtype mark which is passed as a parameter.
+ -- Ada 2005 (AI-231): The flag Not_Null_Present indicates that the
+ -- null-excluding part has been scanned out and it was present.
+
+ function P_Subtype_Mark_Attribute (Type_Node : Node_Id) return Node_Id;
+ -- Parse a subtype mark attribute. The caller has already parsed the
+ -- subtype mark, which is passed in as the argument, and has checked
+ -- that the current token is apostrophe.
+ end Ch3;
+
+ -------------
+ -- Par.Ch4 --
+ -------------
+
+ package Ch4 is
+ function P_Aggregate return Node_Id;
+ function P_Expression return Node_Id;
+ function P_Expression_Or_Range_Attribute return Node_Id;
+ function P_Function_Name return Node_Id;
+ function P_Name return Node_Id;
+ function P_Qualified_Simple_Name return Node_Id;
+ function P_Qualified_Simple_Name_Resync return Node_Id;
+ function P_Simple_Expression return Node_Id;
+ function P_Simple_Expression_Or_Range_Attribute return Node_Id;
+
+ function P_Case_Expression return Node_Id;
+ -- Scans out a case expression. Called with Token pointing to the CASE
+ -- keyword, and returns pointing to the terminating right parent,
+ -- semicolon, or comma, but does not consume this terminating token.
+
+ function P_Expression_If_OK return Node_Id;
+ -- Scans out an expression allowing an unparenthesized case expression,
+ -- if expression, or quantified expression to appear without enclosing
+ -- parentheses. However, if such an expression is not preceded by a left
+ -- paren, and followed by a right paren, an error message will be output
+ -- noting that parenthesization is required.
+
+ function P_Expression_No_Right_Paren return Node_Id;
+ -- Scans out an expression in contexts where the expression cannot be
+ -- terminated by a right paren (gives better error recovery if an errant
+ -- right paren is found after the expression).
+
+ function P_Expression_Or_Range_Attribute_If_OK return Node_Id;
+ -- Scans out an expression or range attribute where a conditional
+ -- expression is permitted to appear without surrounding parentheses.
+ -- However, if such an expression is not preceded by a left paren, and
+ -- followed by a right paren, an error message will be output noting
+ -- that parenthesization is required.
+
+ function P_If_Expression return Node_Id;
+ -- Scans out an if expression. Called with Token pointing to the
+ -- IF keyword, and returns pointing to the terminating right paren,
+ -- semicolon or comma, but does not consume this terminating token.
+
+ function P_Qualified_Expression (Subtype_Mark : Node_Id) return Node_Id;
+ -- This routine scans out a qualified expression when the caller has
+ -- already scanned out the name and apostrophe of the construct.
+
+ function P_Quantified_Expression return Node_Id;
+ -- This routine scans out a quantified expression when the caller has
+ -- already scanned out the keyword "for" of the construct.
+ end Ch4;
+
+ -------------
+ -- Par.Ch5 --
+ -------------
+
+ package Ch5 is
+ function P_Condition return Node_Id;
+ -- Scan out and return a condition
+
+ function P_Loop_Parameter_Specification return Node_Id;
+ -- Used in loop constructs and quantified expressions.
+
+ function P_Sequence_Of_Statements (SS_Flags : SS_Rec) return List_Id;
+ -- The argument indicates the acceptable termination tokens.
+ -- See body in Par.Ch5 for details of the use of this parameter.
+
+ procedure Parse_Decls_Begin_End (Parent : Node_Id);
+ -- Parses declarations and handled statement sequence, setting
+ -- fields of Parent node appropriately.
+ end Ch5;
+
+ -------------
+ -- Par.Ch6 --
+ -------------
+
+ package Ch6 is
+ function P_Designator return Node_Id;
+ function P_Defining_Program_Unit_Name return Node_Id;
+ function P_Formal_Part return List_Id;
+ function P_Parameter_Profile return List_Id;
+ function P_Return_Statement return Node_Id;
+ function P_Subprogram_Specification return Node_Id;
+
+ procedure P_Mode (Node : Node_Id);
+ -- Sets In_Present and/or Out_Present flags in Node scanning past IN,
+ -- OUT or IN OUT tokens in the source.
+
+ function P_Subprogram (Pf_Flags : Pf_Rec) return Node_Id;
+ -- Scans out any construct starting with either of the keywords
+ -- PROCEDURE or FUNCTION. The parameter indicates which possible
+ -- possible kinds of construct (body, spec, instantiation etc.)
+ -- are permissible in the current context.
+ end Ch6;
+
+ -------------
+ -- Par.Ch7 --
+ -------------
+
+ package Ch7 is
+ function P_Package (Pf_Flags : Pf_Rec) return Node_Id;
+ -- Scans out any construct starting with the keyword PACKAGE. The
+ -- parameter indicates which possible kinds of construct (body, spec,
+ -- instantiation etc.) are permissible in the current context.
+ end Ch7;
+
+ -------------
+ -- Par.Ch8 --
+ -------------
+
+ package Ch8 is
+ function P_Use_Clause return Node_Id;
+ end Ch8;
+
+ -------------
+ -- Par.Ch9 --
+ -------------
+
+ package Ch9 is
+ function P_Abort_Statement return Node_Id;
+ function P_Abortable_Part return Node_Id;
+ function P_Accept_Statement return Node_Id;
+ function P_Delay_Statement return Node_Id;
+ function P_Entry_Body return Node_Id;
+ function P_Protected return Node_Id;
+ function P_Requeue_Statement return Node_Id;
+ function P_Select_Statement return Node_Id;
+ function P_Task return Node_Id;
+ function P_Terminate_Alternative return Node_Id;
+ end Ch9;
+
+ --------------
+ -- Par.Ch10 --
+ --------------
+
+ package Ch10 is
+ function P_Compilation_Unit return Node_Id;
+ -- Note: this function scans a single compilation unit, and checks that
+ -- an end of file follows this unit, diagnosing any unexpected input as
+ -- an error, and then skipping it, so that Token is set to Tok_EOF on
+ -- return. An exception is in syntax-only mode, where multiple
+ -- compilation units are permitted. In this case, P_Compilation_Unit
+ -- does not check for end of file and there may be more compilation
+ -- units to scan. The caller can uniquely detect this situation by the
+ -- fact that Token is not set to Tok_EOF on return.
+ --
+ -- What about multiple unit/file capability that now exists???
+ --
+ -- The Ignore parameter is normally set False. It is set True in the
+ -- multiple unit per file mode if we are skipping past a unit that we
+ -- are not interested in.
+ end Ch10;
+
+ --------------
+ -- Par.Ch11 --
+ --------------
+
+ package Ch11 is
+ function P_Handled_Sequence_Of_Statements return Node_Id;
+ function P_Raise_Statement return Node_Id;
+
+ function Parse_Exception_Handlers return List_Id;
+ -- Parses the partial construct EXCEPTION followed by a list of
+ -- exception handlers which appears in a number of productions, and
+ -- returns the list of exception handlers.
+ end Ch11;
+
+ --------------
+ -- Par.Ch12 --
+ --------------
+
+ package Ch12 is
+ function P_Generic return Node_Id;
+ function P_Generic_Actual_Part_Opt return List_Id;
+ end Ch12;
+
+ --------------
+ -- Par.Ch13 --
+ --------------
+
+ package Ch13 is
+ function P_Representation_Clause return Node_Id;
+
+ function Aspect_Specifications_Present
+ (Strict : Boolean := Ada_Version < Ada_2012) return Boolean;
+ -- This function tests whether the next keyword is WITH followed by
+ -- something that looks reasonably like an aspect specification. If so,
+ -- True is returned. Otherwise False is returned. In either case control
+ -- returns with the token pointer unchanged (i.e. pointing to the WITH
+ -- token in the case where True is returned). This function takes care
+ -- of generating appropriate messages if aspect specifications appear
+ -- in versions of Ada prior to Ada 2012. The parameter strict can be
+ -- set to True, to be rather strict about considering something to be
+ -- an aspect specification. If Strict is False, then the circuitry is
+ -- rather more generous in considering something ill-formed to be an
+ -- attempt at an aspect specification. The default is more strict for
+ -- Ada versions before Ada 2012 (where aspect specifications are not
+ -- permitted). Note: this routine never checks the terminator token
+ -- for aspects so it does not matter whether the aspect specifications
+ -- are terminated by semicolon or some other character.
+
+ function Get_Aspect_Specifications
+ (Semicolon : Boolean := True) return List_Id;
+ -- Parse a list of aspects but do not attach them to a declaration node.
+ -- Subsidiary to the following procedure. Used when parsing a subprogram
+ -- specification that may be a declaration or a body.
+
+ procedure P_Aspect_Specifications
+ (Decl : Node_Id;
+ Semicolon : Boolean := True);
+ -- This procedure scans out a series of aspect spefications. If argument
+ -- Semicolon is True, a terminating semicolon is also scanned. If this
+ -- argument is False, the scan pointer is left pointing past the aspects
+ -- and the caller must check for a proper terminator.
+ --
+ -- P_Aspect_Specifications is called with the current token pointing to
+ -- either a WITH keyword starting an aspect specification, or an
+ -- instance of the terminator token. In the former case, the aspect
+ -- specifications are scanned out including the terminator token if it
+ -- it is a semicolon, and the Has_Aspect_Specifications flag is set in
+ -- the given declaration node. A list of aspects is built and stored for
+ -- this declaration node using a call to Set_Aspect_Specifications. If
+ -- no WITH keyword is present, then this call has no effect other than
+ -- scanning out the terminator if it is a semicolon.
+
+ -- If Decl is Error on entry, any scanned aspect specifications are
+ -- ignored and a message is output saying aspect specifications not
+ -- permitted here. If Decl is Empty, then scanned aspect specifications
+ -- are also ignored, but no error message is given (this is used when
+ -- the caller has already taken care of the error message).
+
+ function P_Code_Statement (Subtype_Mark : Node_Id) return Node_Id;
+ -- Function to parse a code statement. The caller has scanned out
+ -- the name to be used as the subtype mark (but has not checked that
+ -- it is suitable for use as a subtype mark, i.e. is either an
+ -- identifier or a selected component). The current token is an
+ -- apostrophe and the following token is either a left paren or
+ -- RANGE (the latter being an error to be caught by P_Code_Statement.
+ end Ch13;
+
+ -- Note: the parsing for annexe J features (i.e. obsolescent features)
+ -- is found in the logical section where these features would be if
+ -- they were not obsolescent. In particular:
+
+ -- Delta constraint is parsed by P_Delta_Constraint (3.5.9)
+ -- At clause is parsed by P_At_Clause (13.1)
+ -- Mod clause is parsed by P_Mod_Clause (13.5.1)
+
+ --------------
+ -- Par.Endh --
+ --------------
+
+ -- Routines for handling end lines, including scope recovery
+
+ package Endh is
+ function Check_End
+ (Decl : Node_Id := Empty;
+ Is_Loc : Source_Ptr := No_Location) return Boolean;
+ -- Called when an end sequence is required. In the absence of an error
+ -- situation, Token contains Tok_End on entry, but in a missing end
+ -- case, this may not be the case. Pop_End_Context is used to determine
+ -- the appropriate action to be taken. The returned result is True if
+ -- an End sequence was encountered and False if no End sequence was
+ -- present. This occurs if the END keyword encountered was determined
+ -- to be improper and deleted (i.e. Pop_End_Context set End_Action to
+ -- Skip_And_Reject). Note that the END sequence includes a semicolon,
+ -- except in the case of END RECORD, where a semicolon follows the END
+ -- RECORD, but is not part of the record type definition itself.
+ --
+ -- If Decl is non-empty, then aspect specifications are permitted
+ -- following the end, and Decl is the declaration node with which
+ -- these aspect specifications are to be associated. If Decl is empty,
+ -- then aspect specifications are not permitted and will generate an
+ -- error message.
+ --
+ -- Is_Loc is set to other than the default only for the case of a
+ -- package declaration. It points to the IS keyword of the declaration,
+ -- and is used to specialize the error messages for misplaced aspect
+ -- specifications in this case. Note that Decl is always Empty if Is_Loc
+ -- is set.
+
+ procedure End_Skip;
+ -- Skip past an end sequence. On entry Token contains Tok_End, and we
+ -- we know that the end sequence is syntactically incorrect, and that
+ -- an appropriate error message has already been posted. The mission
+ -- is simply to position the scan pointer to be the best guess of the
+ -- position after the end sequence. We do not issue any additional
+ -- error messages while carrying this out.
+
+ procedure End_Statements
+ (Parent : Node_Id := Empty;
+ Decl : Node_Id := Empty;
+ Is_Sloc : Source_Ptr := No_Location);
+ -- Called when an end is required or expected to terminate a sequence
+ -- of statements. The caller has already made an appropriate entry in
+ -- the Scope.Table to describe the expected form of the end. This can
+ -- only be used in cases where the only appropriate terminator is end.
+ -- If Parent is non-empty, then if a correct END line is encountered,
+ -- the End_Label field of Parent is set appropriately.
+ --
+ -- If Decl is non-null, then it is a declaration node, and aspect
+ -- specifications are permitted after the end statement. These aspect
+ -- specifications, if present, are stored in this declaration node.
+ -- If Decl is null, then aspect specifications are not permitted after
+ -- the end statement.
+ --
+ -- In the case where Decl is null, Is_Sloc determines the handling. If
+ -- it is set to No_Location, then aspect specifications are ignored and
+ -- an error message is given. Is_Sloc is used in the package declaration
+ -- case to point to the IS, and is used to specialize the error emssages
+ -- issued in this case.
+ end Endh;
+
+ --------------
+ -- Par.Sync --
+ --------------
+
+ -- These procedures are used to resynchronize after errors. Following an
+ -- error which is not immediately locally recoverable, the exception
+ -- Error_Resync is raised. The handler for Error_Resync typically calls
+ -- one of these recovery procedures to resynchronize the source position
+ -- to a point from which parsing can be restarted.
+
+ -- Note: these procedures output an information message that tokens are
+ -- being skipped, but this message is output only if the option for
+ -- Multiple_Errors_Per_Line is set in Options.
+
+ package Sync is
+ procedure Resync_Choice;
+ -- Used if an error occurs scanning a choice. The scan pointer is
+ -- advanced to the next vertical bar, arrow, or semicolon, whichever
+ -- comes first. We also quit if we encounter an end of file.
+
+ procedure Resync_Expression;
+ -- Used if an error is detected during the parsing of an expression.
+ -- It skips past tokens until either a token which cannot be part of
+ -- an expression is encountered (an expression terminator), or if a
+ -- comma or right parenthesis or vertical bar is encountered at the
+ -- current parenthesis level (a parenthesis level counter is maintained
+ -- to carry out this test).
+
+ procedure Resync_Past_Semicolon;
+ -- Used if an error occurs while scanning a sequence of declarations.
+ -- The scan pointer is positioned past the next semicolon and the scan
+ -- resumes. The scan is also resumed on encountering a token which
+ -- starts a declaration (but we make sure to skip at least one token
+ -- in this case, to avoid getting stuck in a loop).
+
+ procedure Resync_To_Semicolon;
+ -- Similar to Resync_Past_Semicolon, except that the scan pointer is
+ -- left pointing to the semicolon rather than past it.
+
+ procedure Resync_Past_Semicolon_Or_To_Loop_Or_Then;
+ -- Used if an error occurs while scanning a sequence of statements. The
+ -- scan pointer is positioned past the next semicolon, or to the next
+ -- occurrence of either then or loop, and the scan resumes.
+
+ procedure Resync_To_When;
+ -- Used when an error occurs scanning an entry index specification. The
+ -- scan pointer is positioned to the next WHEN (or to IS or semicolon if
+ -- either of these appear before WHEN, indicating another error has
+ -- occurred).
+
+ procedure Resync_Semicolon_List;
+ -- Used if an error occurs while scanning a parenthesized list of items
+ -- separated by semicolons. The scan pointer is advanced to the next
+ -- semicolon or right parenthesis at the outer parenthesis level, or
+ -- to the next is or RETURN keyword occurrence, whichever comes first.
+
+ procedure Resync_Cunit;
+ -- Synchronize to next token which could be the start of a compilation
+ -- unit, or to the end of file token.
+ end Sync;
+
+ --------------
+ -- Par.Tchk --
+ --------------
+
+ -- Routines to check for expected tokens
+
+ package Tchk is
+
+ -- Procedures with names of the form T_xxx, where Tok_xxx is a token
+ -- name, check that the current token matches the required token, and
+ -- if so, scan past it. If not, an error is issued indicating that
+ -- the required token is not present (xxx expected). In most cases, the
+ -- scan pointer is not moved in the not-found case, but there are some
+ -- exceptions to this, see for example T_Id, where the scan pointer is
+ -- moved across a literal appearing where an identifier is expected.
+
+ procedure T_Abort;
+ procedure T_Arrow;
+ procedure T_At;
+ procedure T_Body;
+ procedure T_Box;
+ procedure T_Colon;
+ procedure T_Colon_Equal;
+ procedure T_Comma;
+ procedure T_Dot_Dot;
+ procedure T_For;
+ procedure T_Greater_Greater;
+ procedure T_Identifier;
+ procedure T_In;
+ procedure T_Is;
+ procedure T_Left_Paren;
+ procedure T_Loop;
+ procedure T_Mod;
+ procedure T_New;
+ procedure T_Of;
+ procedure T_Or;
+ procedure T_Private;
+ procedure T_Range;
+ procedure T_Record;
+ procedure T_Right_Paren;
+ procedure T_Semicolon;
+ procedure T_Then;
+ procedure T_Type;
+ procedure T_Use;
+ procedure T_When;
+ procedure T_With;
+
+ -- Procedures having names of the form TF_xxx, where Tok_xxx is a token
+ -- name check that the current token matches the required token, and
+ -- if so, scan past it. If not, an error message is issued indicating
+ -- that the required token is not present (xxx expected).
+
+ -- If the missing token is at the end of the line, then control returns
+ -- immediately after posting the message. If there are remaining tokens
+ -- on the current line, a search is conducted to see if the token
+ -- appears later on the current line, as follows:
+
+ -- A call to Scan_Save is issued and a forward search for the token
+ -- is carried out. If the token is found on the current line before a
+ -- semicolon, then it is scanned out and the scan continues from that
+ -- point. If not the scan is restored to the point where it was missing.
+
+ procedure TF_Arrow;
+ procedure TF_Is;
+ procedure TF_Loop;
+ procedure TF_Return;
+ procedure TF_Semicolon;
+ procedure TF_Then;
+ procedure TF_Use;
+
+ -- Procedures with names of the form U_xxx, where Tok_xxx is a token
+ -- name, are just like the corresponding T_xxx procedures except that
+ -- an error message, if given, is unconditional.
+
+ procedure U_Left_Paren;
+ procedure U_Right_Paren;
+ end Tchk;
+
+ --------------
+ -- Par.Util --
+ --------------
+
+ package Util is
+ function Bad_Spelling_Of (T : Token_Type) return Boolean;
+ -- This function is called in an error situation. It checks if the
+ -- current token is an identifier whose name is a plausible bad
+ -- spelling of the given keyword token, and if so, issues an error
+ -- message, sets Token from T, and returns True. Otherwise Token is
+ -- unchanged, and False is returned.
+
+ procedure Check_Bad_Layout;
+ -- Check for bad indentation in RM checking mode. Used for statements
+ -- and declarations. Checks if current token is at start of line and
+ -- is exdented from the current expected end column, and if so an
+ -- error message is generated.
+
+ procedure Check_Misspelling_Of (T : Token_Type);
+ pragma Inline (Check_Misspelling_Of);
+ -- This is similar to the function above, except that it does not
+ -- return a result. It is typically used in a situation where any
+ -- identifier is an error, and it makes sense to simply convert it
+ -- to the given token if it is a plausible misspelling of it.
+
+ procedure Check_95_Keyword (Token_95, Next : Token_Type);
+ -- This routine checks if the token after the current one matches the
+ -- Next argument. If so, the scan is backed up to the current token
+ -- and Token_Type is changed to Token_95 after issuing an appropriate
+ -- error message ("(Ada 83) keyword xx cannot be used"). If not,
+ -- the scan is backed up with Token_Type unchanged. This routine
+ -- is used to deal with an attempt to use a 95 keyword in Ada 83
+ -- mode. The caller has typically checked that the current token,
+ -- an identifier, matches one of the 95 keywords.
+
+ procedure Check_Future_Keyword;
+ -- Emit a warning if the current token is a valid identifier in the
+ -- language version in use, but is a reserved word in a later language
+ -- version (unless the language version in use is Ada 83).
+
+ procedure Check_Simple_Expression (E : Node_Id);
+ -- Given an expression E, that has just been scanned, so that Expr_Form
+ -- is still set, outputs an error if E is a non-simple expression. E is
+ -- not modified by this call.
+
+ procedure Check_Simple_Expression_In_Ada_83 (E : Node_Id);
+ -- Like Check_Simple_Expression, except that the error message is only
+ -- given when operating in Ada 83 mode, and includes "in Ada 83".
+
+ function Check_Subtype_Mark (Mark : Node_Id) return Node_Id;
+ -- Called to check that a node representing a name (or call) is
+ -- suitable for a subtype mark, i.e, that it is an identifier or
+ -- a selected component. If so, or if it is already Error, then
+ -- it is returned unchanged. Otherwise an error message is issued
+ -- and Error is returned.
+
+ function Comma_Present return Boolean;
+ -- Used in comma delimited lists to determine if a comma is present, or
+ -- can reasonably be assumed to have been present (an error message is
+ -- generated in the latter case). If True is returned, the scan has been
+ -- positioned past the comma. If False is returned, the scan position
+ -- is unchanged. Note that all comma-delimited lists are terminated by
+ -- a right paren, so the only legitimate tokens when Comma_Present is
+ -- called are right paren and comma. If some other token is found, then
+ -- Comma_Present has the job of deciding whether it is better to pretend
+ -- a comma was present, post a message for a missing comma and return
+ -- True, or return False and let the caller diagnose the missing right
+ -- parenthesis.
+
+ procedure Discard_Junk_Node (N : Node_Id);
+ procedure Discard_Junk_List (L : List_Id);
+ pragma Inline (Discard_Junk_Node);
+ pragma Inline (Discard_Junk_List);
+ -- These procedures do nothing at all, their effect is simply to discard
+ -- the argument. A typical use is to skip by some junk that is not
+ -- expected in the current context.
+
+ procedure Ignore (T : Token_Type);
+ -- If current token matches T, then give an error message and skip
+ -- past it, otherwise the call has no effect at all. T may be any
+ -- reserved word token, or comma, left or right paren, or semicolon.
+
+ function Is_Reserved_Identifier (C : Id_Check := None) return Boolean;
+ -- Test if current token is a reserved identifier. This test is based
+ -- on the token being a keyword and being spelled in typical identifier
+ -- style (i.e. starting with an upper case letter). The parameter C
+ -- determines the special treatment if a reserved word is encountered
+ -- that has the normal casing of a reserved word.
+
+ procedure Merge_Identifier (Prev : Node_Id; Nxt : Token_Type);
+ -- Called when the previous token is an identifier (whose Token_Node
+ -- value is given by Prev) to check if current token is an identifier
+ -- that can be merged with the previous one adding an underscore. The
+ -- merge is only attempted if the following token matches Nxt. If all
+ -- conditions are met, an error message is issued, and the merge is
+ -- carried out, modifying the Chars field of Prev.
+
+ function Next_Token_Is (Tok : Token_Type) return Boolean;
+ -- Looks at token after current one and returns True if the token type
+ -- matches Tok. The scan is unconditionally restored on return.
+
+ procedure No_Constraint;
+ -- Called in a place where no constraint is allowed, but one might
+ -- appear due to a common error (e.g. after the type mark in a procedure
+ -- parameter. If a constraint is present, an error message is posted,
+ -- and the constraint is scanned and discarded.
+
+ procedure Push_Scope_Stack;
+ pragma Inline (Push_Scope_Stack);
+ -- Push a new entry onto the scope stack. Scope.Last (the stack pointer)
+ -- is incremented. The Junk field is preinitialized to False. The caller
+ -- is expected to fill in all remaining entries of the new top stack
+ -- entry at Scope.Table (Scope.Last).
+
+ procedure Pop_Scope_Stack;
+ -- Pop an entry off the top of the scope stack. Scope_Last (the scope
+ -- table stack pointer) is decremented by one. It is a fatal error to
+ -- try to pop off the dummy entry at the bottom of the stack (i.e.
+ -- Scope.Last must be non-zero at the time of call).
+
+ function Separate_Present return Boolean;
+ -- Determines if the current token is either Tok_Separate, or an
+ -- identifier that is a possible misspelling of "separate" followed
+ -- by a semicolon. True is returned if so, otherwise False.
+
+ procedure Signal_Bad_Attribute;
+ -- The current token is an identifier that is supposed to be an
+ -- attribute identifier but is not. This routine posts appropriate
+ -- error messages, including a check for a near misspelling.
+
+ function Token_Is_At_Start_Of_Line return Boolean;
+ pragma Inline (Token_Is_At_Start_Of_Line);
+ -- Determines if the current token is the first token on the line
+
+ function Token_Is_At_End_Of_Line return Boolean;
+ -- Determines if the current token is the last token on the line
+
+ procedure Warn_If_Standard_Redefinition (N : Node_Id);
+ -- Issues a warning if Warn_On_Standard_Redefinition is set True, and
+ -- the Node N (which is a Defining_Identifier node with the Chars field
+ -- set) is a renaming of an entity in package Standard.
+
+ end Util;
+
+ --------------
+ -- Par.Prag --
+ --------------
+
+ -- The processing for pragmas is split off from chapter 2
+
+ function Prag (Pragma_Node : Node_Id; Semi : Source_Ptr) return Node_Id;
+ -- This function is passed a tree for a pragma that has been scanned out.
+ -- The pragma is syntactically well formed according to the general syntax
+ -- for pragmas and the pragma identifier is for one of the recognized
+ -- pragmas. It performs specific syntactic checks for specific pragmas.
+ -- The result is the input node if it is OK, or Error otherwise. The
+ -- reason that this is separated out is to facilitate the addition
+ -- of implementation defined pragmas. The second parameter records the
+ -- location of the semicolon following the pragma (this is needed for
+ -- correct processing of the List and Page pragmas). The returned value
+ -- is a copy of Pragma_Node, or Error if an error is found. Note that
+ -- at the point where Prag is called, the right paren ending the pragma
+ -- has been scanned out, and except in the case of pragma Style_Checks,
+ -- so has the following semicolon. For Style_Checks, the caller delays
+ -- the scanning of the semicolon so that it will be scanned using the
+ -- settings from the Style_Checks pragma preceding it.
+
+ --------------
+ -- Par.Labl --
+ --------------
+
+ procedure Labl;
+ -- This procedure creates implicit label declarations for all labels that
+ -- are declared in the current unit. Note that this could conceptually be
+ -- done at the point where the labels are declared, but it is tricky to do
+ -- it then, since the tree is not hooked up at the point where the label is
+ -- declared (e.g. a sequence of statements is not yet attached to its
+ -- containing scope at the point a label in the sequence is found).
+
+ --------------
+ -- Par.Load --
+ --------------
+
+ procedure Load;
+ -- This procedure loads all subsidiary units that are required by this
+ -- unit, including with'ed units, specs for bodies, and parents for child
+ -- units. It does not load bodies for inlined procedures and generics,
+ -- since we don't know till semantic analysis is complete what is needed.
+
+ -----------
+ -- Stubs --
+ -----------
+
+ -- The package bodies can see all routines defined in all other subpackages
+
+ use Ch2;
+ use Ch3;
+ use Ch4;
+ use Ch5;
+ use Ch6;
+ use Ch7;
+ use Ch8;
+ use Ch9;
+ use Ch10;
+ use Ch11;
+ use Ch12;
+ use Ch13;
+
+ use Endh;
+ use Tchk;
+ use Sync;
+ use Util;
+
+ package body Ch2 is separate;
+ package body Ch3 is separate;
+ package body Ch4 is separate;
+ package body Ch5 is separate;
+ package body Ch6 is separate;
+ package body Ch7 is separate;
+ package body Ch8 is separate;
+ package body Ch9 is separate;
+ package body Ch10 is separate;
+ package body Ch11 is separate;
+ package body Ch12 is separate;
+ package body Ch13 is separate;
+
+ package body Endh is separate;
+ package body Tchk is separate;
+ package body Sync is separate;
+ package body Util is separate;
+
+ function Prag (Pragma_Node : Node_Id; Semi : Source_Ptr) return Node_Id
+ is separate;
+
+ procedure Labl is separate;
+ procedure Load is separate;
+
+-- Start of processing for Par
+
+begin
+ Compiler_State := Parsing;
+
+ -- Deal with configuration pragmas case first
+
+ if Configuration_Pragmas then
+ declare
+ Pragmas : constant List_Id := Empty_List;
+ P_Node : Node_Id;
+
+ begin
+ loop
+ if Token = Tok_EOF then
+ Compiler_State := Analyzing;
+ return Pragmas;
+
+ elsif Token /= Tok_Pragma then
+ Error_Msg_SC ("only pragmas allowed in configuration file");
+ Compiler_State := Analyzing;
+ return Error_List;
+
+ else
+ P_Node := P_Pragma;
+
+ if Nkind (P_Node) = N_Pragma then
+
+ -- Give error if bad pragma
+
+ if not Is_Configuration_Pragma_Name (Pragma_Name (P_Node))
+ and then Pragma_Name (P_Node) /= Name_Source_Reference
+ then
+ if Is_Pragma_Name (Pragma_Name (P_Node)) then
+ Error_Msg_N
+ ("only configuration pragmas allowed " &
+ "in configuration file", P_Node);
+ else
+ Error_Msg_N
+ ("unrecognized pragma in configuration file",
+ P_Node);
+ end if;
+
+ -- Pragma is OK config pragma, so collect it
+
+ else
+ Append (P_Node, Pragmas);
+ end if;
+ end if;
+ end if;
+ end loop;
+ end;
+
+ -- Normal case of compilation unit
+
+ else
+ Save_Opt_Config_Switches (Save_Config_Switches);
+
+ -- The following loop runs more than once in syntax check mode
+ -- where we allow multiple compilation units in the same file
+ -- and in Multiple_Unit_Per_file mode where we skip units till
+ -- we get to the unit we want.
+
+ for Ucount in Pos loop
+ Set_Opt_Config_Switches
+ (Is_Internal_File_Name (File_Name (Current_Source_File)),
+ Current_Source_Unit = Main_Unit);
+
+ -- Initialize scope table and other parser control variables
+
+ Compiler_State := Parsing;
+ Scope.Init;
+ Scope.Increment_Last;
+ Scope.Table (0).Etyp := E_Dummy;
+ SIS_Entry_Active := False;
+ Last_Resync_Point := No_Location;
+
+ Goto_List := New_Elmt_List;
+ Label_List := New_Elmt_List;
+
+ -- If in multiple unit per file mode, skip past ignored unit
+
+ if Ucount < Multiple_Unit_Index then
+
+ -- We skip in syntax check only mode, since we don't want to do
+ -- anything more than skip past the unit and ignore it. This means
+ -- we skip processing like setting up a unit table entry.
+
+ declare
+ Save_Operating_Mode : constant Operating_Mode_Type :=
+ Operating_Mode;
+
+ Save_Style_Check : constant Boolean := Style_Check;
+
+ begin
+ Operating_Mode := Check_Syntax;
+ Style_Check := False;
+ Discard_Node (P_Compilation_Unit);
+ Operating_Mode := Save_Operating_Mode;
+ Style_Check := Save_Style_Check;
+
+ -- If we are at an end of file, and not yet at the right unit,
+ -- then we have a fatal error. The unit is missing.
+
+ if Token = Tok_EOF then
+ Error_Msg_SC ("file has too few compilation units");
+ raise Unrecoverable_Error;
+ end if;
+ end;
+
+ -- Here if we are not skipping a file in multiple unit per file mode.
+ -- Parse the unit that we are interested in. Note that in check
+ -- syntax mode we are interested in all units in the file.
+
+ else
+ declare
+ Comp_Unit_Node : constant Node_Id := P_Compilation_Unit;
+
+ begin
+ -- If parsing was successful and we are not in check syntax
+ -- mode, check that language-defined units are compiled in GNAT
+ -- mode. For this purpose we do NOT consider renamings in annex
+ -- J as predefined. That allows users to compile their own
+ -- versions of these files, and in particular, in the VMS
+ -- implementation, the DEC versions can be substituted for the
+ -- standard Ada 95 versions. Another exception is System.RPC
+ -- and its children. This allows a user to supply their own
+ -- communication layer.
+
+ if Comp_Unit_Node /= Error
+ and then Operating_Mode = Generate_Code
+ and then Current_Source_Unit = Main_Unit
+ and then not GNAT_Mode
+ then
+ declare
+ Uname : constant String :=
+ Get_Name_String
+ (Unit_Name (Current_Source_Unit));
+ Name : String (1 .. Uname'Length - 2);
+
+ begin
+ -- Because Unit_Name includes "%s"/"%b", we need to strip
+ -- the last two characters to get the real unit name.
+
+ Name := Uname (Uname'First .. Uname'Last - 2);
+
+ if Name = "ada" or else
+ Name = "interfaces" or else
+ Name = "system"
+ then
+ Error_Msg
+ ("language-defined units cannot be recompiled",
+ Sloc (Unit (Comp_Unit_Node)));
+
+ elsif Name'Length > 4
+ and then
+ Name (Name'First .. Name'First + 3) = "ada."
+ then
+ Error_Msg
+ ("user-defined descendents of package Ada " &
+ "are not allowed",
+ Sloc (Unit (Comp_Unit_Node)));
+
+ elsif Name'Length > 11
+ and then
+ Name (Name'First .. Name'First + 10) = "interfaces."
+ then
+ Error_Msg
+ ("user-defined descendents of package Interfaces " &
+ "are not allowed",
+ Sloc (Unit (Comp_Unit_Node)));
+
+ elsif Name'Length > 7
+ and then Name (Name'First .. Name'First + 6) = "system."
+ and then Name /= "system.rpc"
+ and then
+ (Name'Length < 11
+ or else Name (Name'First .. Name'First + 10) /=
+ "system.rpc.")
+ then
+ Error_Msg
+ ("user-defined descendents of package System " &
+ "are not allowed",
+ Sloc (Unit (Comp_Unit_Node)));
+ end if;
+ end;
+ end if;
+ end;
+
+ -- All done if at end of file
+
+ exit when Token = Tok_EOF;
+
+ -- If we are not at an end of file, it means we are in syntax
+ -- check only mode, and we keep the loop going to parse all
+ -- remaining units in the file.
+
+ end if;
+
+ Restore_Opt_Config_Switches (Save_Config_Switches);
+ end loop;
+
+ -- Now that we have completely parsed the source file, we can complete
+ -- the source file table entry.
+
+ Complete_Source_File_Entry;
+
+ -- An internal error check, the scope stack should now be empty
+
+ pragma Assert (Scope.Last = 0);
+
+ -- Here we make the SCO table entries for the main unit
+
+ if Generate_SCO then
+ SCO_Record (Main_Unit);
+ end if;
+
+ -- Remaining steps are to create implicit label declarations and to load
+ -- required subsidiary sources. These steps are required only if we are
+ -- doing semantic checking.
+
+ if Operating_Mode /= Check_Syntax or else Debug_Flag_F then
+ Par.Labl;
+ Par.Load;
+ end if;
+
+ -- Restore settings of switches saved on entry
+
+ Restore_Opt_Config_Switches (Save_Config_Switches);
+ Set_Comes_From_Source_Default (False);
+ Compiler_State := Analyzing;
+ return Empty_List;
+ end if;
+end Par;