| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT COMPILER COMPONENTS -- |
| -- -- |
| -- P A R -- |
| -- -- |
| -- B o d y -- |
| -- -- |
| -- Copyright (C) 1992-2022, 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 Sinfo.Nodes; use Sinfo.Nodes; |
| with Sinfo.Utils; use Sinfo.Utils; |
| 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 |
| |
| Inside_Record_Definition : Boolean := False; |
| -- True within a record definition. Used to control warning for |
| -- redefinition of standard entities (not issued for field names). |
| |
| Loop_Block_Count : Nat := 0; |
| -- Counter used for constructing loop/block names (see the routine |
| -- Par.Ch5.Get_Loop_Block_Name). |
| |
| 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_Attrs : 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. |
| |
| -------------------- |
| -- 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 variables other than |
| -- SIS_Aspect_Import_Seen are valid only if this is True. |
| |
| SIS_Aspect_Import_Seen : Boolean := False; |
| -- If this is True when a subprogram declaration has been encountered, we |
| -- do not set SIS_Entry_Active, because the Import means there is no body. |
| -- Set False at the start of P_Subprogram, set True when an Import aspect |
| -- specification is seen, and used when P_Subprogram finds a subprogram |
| -- declaration. This is necessary because the aspects are parsed before |
| -- we know we have a subprogram declaration. |
| |
| 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 |
| -- corresponding 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"); |
| |
| type Scope_Table_Entry_Ptr is access all Scope_Table_Entry; |
| |
| function Scopes (Index : Int) return Scope_Table_Entry_Ptr; |
| -- Return the indicated Scope_Table_Entry. We use a pointer for |
| -- efficiency. Callers should not save the pointer, but should do things |
| -- like Scopes (Scope.Last).Something. Note that there is one place in |
| -- Par.Ch5 that indexes the stack out of bounds, and can't call this. |
| |
| function Scopes (Index : Int) return Scope_Table_Entry_Ptr is |
| begin |
| pragma Assert (Index in Scope.First .. Scope.Last); |
| return Scope.Table (Index)'Unrestricted_Access; |
| end Scopes; |
| |
| ------------------------------------------ |
| -- Table for Handling Suspicious Labels -- |
| ------------------------------------------ |
| |
| -- This is a special data structure which is used to deal very specifically |
| -- 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; |
| Force_Msg : Boolean := False) return Node_Id; |
| -- Scans out an identifier. The parameter C determines the treatment |
| -- of reserved identifiers. See declaration of Id_Check for details. |
| |
| -- An appropriate error message, pointing to the token, is also issued |
| -- if either this is the first occurrence of misuse of this identifier, |
| -- or if Force_Msg is True. |
| |
| 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_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_Basic_Declarative_Items |
| (Declare_Expression : Boolean) return List_Id; |
| -- Used to parse the declarative items in a package visible or |
| -- private part (in which case Declare_Expression is False), and |
| -- the declare_items of a declare_expression (in which case |
| -- Declare_Expression is True). Declare_Expression is used to |
| -- affect the wording of error messages, and to control style |
| -- checking. |
| |
| 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_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_Iterator_Specification (Def_Id : Node_Id) return Node_Id; |
| -- Parse an iterator specification. The defining identifier has already |
| -- been scanned, as it is the common prefix between loop and iterator |
| -- specification. |
| |
| 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 specifications. 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_Bracket; |
| 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 Missing_Semicolon_On_When return Boolean; |
| -- This function deals with the following specialized situations |
| -- |
| -- when 'x' => |
| -- exit/return [identifier] |
| -- when 'y' => |
| -- |
| -- This looks like a messed up EXIT WHEN or RETURN WHEN, when in fact |
| -- the problem is a missing semicolon. It is called with Token pointing |
| -- to the WHEN token, and returns True if a semicolon is missing before |
| -- the WHEN as in the above example. |
| |
| 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 Scopes (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; |
| |
| if Config_Files_Store_Basename then |
| Complete_Source_File_Entry; |
| end if; |
| |
| -- Normal case of compilation unit |
| |
| else |
| Save_Config_Attrs := 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_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; |
| Scopes (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 renames |
| Uname (Uname'First .. Uname'Last - 2); |
| -- Because Unit_Name includes "%s"/"%b", we need to strip |
| -- the last two characters to get the real unit name. |
| |
| begin |
| 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_Config_Switches (Save_Config_Attrs); |
| 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_Config_Switches (Save_Config_Attrs); |
| Set_Comes_From_Source_Default (False); |
| end if; |
| |
| Compiler_State := Analyzing; |
| Current_Source_File := No_Source_File; |
| return Result; |
| end Par; |
