CbC/CbC_gcc: gcc/ada/par.adb comparison

comparison gcc/ada/par.adb @ 111:04ced10e8804

gcc 7

author	kono
date	Fri, 27 Oct 2017 22:46:09 +0900
parents
children	84e7813d76e9

comparison

equal deleted inserted replaced

-:561a7518be6b
+:04ced10e8804
+------------------------------------------------------------------------------
+--                                                                          --
+--                         GNAT COMPILER COMPONENTS                         --
+--                                                                          --
+--                                  P A R                                   --
+--                                                                          --
+--                                 B o d y                                  --
+--                                                                          --
+--          Copyright (C) 1992-2017, 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;
+--  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 parameterized 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. This value is zero origin.
+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, return 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");
+------------------------------------------
+-- Table for Handling Suspicious Labels --
+------------------------------------------
+--  This is a special data structure which is used to deal very spefifically
+--  with the following error case
+--     label;
+--     loop
+--       ...
+--     end loop label;
+--  Similar cases apply to FOR, WHILE, DECLARE, or BEGIN
+--  In each case the opening line looks like a procedure call because of
+--  the semicolon. And the end line looks illegal because of an unexpected
+--  label. If we did nothing special, we would just diagnose the label on
+--  the end as unexpected. But that does not help point to the real error
+--  which is that the semicolon after label should be a colon.
+--  To deal with this, we build an entry in the Suspicious_Labels table
+--  whenever we encounter an identifier followed by a semicolon, followed
+--  by one of LOOP, FOR, WHILE, DECLARE, BEGIN. Then this entry is used to
+--  issue the right message when we hit the END that confirms that this was
+--  a bad label.
+type Suspicious_Label_Entry is record
+Proc_Call : Node_Id;
+--  Node for the procedure call statement built for the label; construct
+Semicolon_Loc : Source_Ptr;
+--  Location of the possibly wrong semicolon
+Start_Token : Source_Ptr;
+--  Source location of the LOOP, FOR, WHILE, DECLARE, BEGIN token
+end record;
+package Suspicious_Labels is new Table.Table (
+Table_Component_Type => Suspicious_Label_Entry,
+Table_Index_Type     => Int,
+Table_Low_Bound      => 1,
+Table_Initial        => 50,
+Table_Increment      => 100,
+Table_Name           => "Suspicious_Labels");
+--  Now when we are about to issue a message complaining about an END label
+--  that should not be there because it appears to end a construct that has
+--  no label, we first search the suspicious labels table entry, using the
+--  source location stored in the scope table as a key. If we find a match,
+--  then we check that the label on the end matches the name in the call,
+--  and if so, we issue a message saying the semicolon should be a colon.
+--  Quite a bit of work, but really helpful in the case where it helps, and
+--  the need for this is based on actual experience with tracking down this
+--  kind of error (the eye often easily mistakes semicolon for colon).
+--  Note: we actually have enough information to patch up the tree, but
+--  this may not be worth the effort. Also we could deal with the same
+--  situation for EXIT with a label, but for now don't bother with that.
+Current_Assign_Node : Node_Id := Empty;
+--  This is the node of the current assignment statement being compiled.
+--  It is used to record the presence of target_names on its RHS. This
+--  context-dependent trick simplifies the analysis of such nodes, where
+--  the RHS must first be analyzed with expansion disabled.
+---------------------------------
+-- 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). Some pragmas must be dealt with during
+--  the parsing phase (e.g. pragma Page, since we can generate a listing
+--  in syntax only mode). It is possible that the parser uses the rescan
+--  logic (using Save/Restore_Scan_State) with the effect of calling this
+--  procedure more than once for the same pragma. All parse-time pragma
+--  handling must be prepared to handle such multiple calls correctly.
+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. Note that an error is given if
+--  the condition is followed by a right parenthesis.
+function P_Condition (Cond : Node_Id) return Node_Id;
+--  Similar to the above, but the caller has already scanned out the
+--  conditional expression and passes it as an argument. This form of
+--  the call does not check for a following right parenthesis.
+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
+procedure P_Use_Clause (Item_List : List_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_Expression                     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.
+--
+--  Note: This function also handles the case of WHEN used where WITH
+--  was intended, and in that case posts an error and returns True.
+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 what shpould be a terminator token. In the former case,
+--  the aspect specifications are scanned out including the terminator
+--  token if 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 (with the exception that it detects WHEN used in place of
+--  WITH).
+--  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 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 P_Aspect_Specifications procedure. Used when parsing
+--  a subprogram specification that may be a declaration or a body.
+--  Semicolon has the same meaning as for P_Aspect_Specifications above.
+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_Cunit;
+--  Synchronize to next token which could be the start of a compilation
+--  unit, or to the end of file token.
+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_Malformed_Aspect;
+--  Used when parsing aspect specifications to skip a malformed aspect.
+--  The scan pointer is positioned next to a comma, a semicolon or "is"
+--  when the aspect applies to a body.
+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_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_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_To_Semicolon;
+--  Similar to Resync_Past_Semicolon, except that the scan pointer is
+--  left pointing to the semicolon rather than past it.
+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).
+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;
+Result : List_Id := Empty_List;
+--  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
+Result := Pragmas;
+exit;
+elsif Token /= Tok_Pragma then
+Error_Msg_SC ("only pragmas allowed in configuration file");
+Result := Error_List;
+exit;
+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_Unmapped (P_Node))
+and then
+Pragma_Name_Unmapped (P_Node) /= Name_Source_Reference
+then
+if Is_Pragma_Name (Pragma_Name_Unmapped (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_Unit (Current_Source_Unit),
+Main_Unit => 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. Another exception is System.RPC
+--  and its children. This allows a user to supply their own
+--  communication layer.
+--  Similarly, we do not generate an error in CodePeer mode,
+--  to allow users to analyze third-party compiler packages.
+if Comp_Unit_Node /= Error
+and then Operating_Mode = Generate_Code
+and then Current_Source_Unit = Main_Unit
+and then not GNAT_Mode
+and then not CodePeer_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 descendants 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 descendants 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 descendants 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_Raw (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);
+end if;
+Compiler_State      := Analyzing;
+Current_Source_File := No_Source_File;
+return Result;
+end Par;

Mercurial > hg > CbC > CbC_gcc

comparison gcc/ada/par.adb @ 111:04ced10e8804