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gcc/gcc/ada/scn.adb
Arnaud Charlet 90c63b098c [multiple changes] 
2010-10-21  Robert Dewar  <dewar@adacore.com>

	* exp_ch4.adb, exp_intr.adb, par-ch4.adb, scn.adb, sem_ch4.adb,
	sem_res.adb, sem_util.adb, sinfo.ads, a-except-2005.adb: Minor
	reformatting.
	* snames.ads-tmpl: Add note on Name_Some (not a reserved keyword).

2010-10-21  Geert Bosch  <bosch@adacore.com>

	* ttypef.ads: Further cleanup of Safe_XXX float attributes.

From-SVN: r165756
2010-10-21 11:52:52 +02:00

495 lines
16 KiB
Ada
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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- S C N --
-- --
-- B o d y --
-- --
-- Copyright (C) 1992-2010, 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 Atree; use Atree;
with Csets; use Csets;
with Hostparm; use Hostparm;
with Namet; use Namet;
with Opt; use Opt;
with Output; use Output;
with Restrict; use Restrict;
with Rident; use Rident;
with Scans; use Scans;
with Sinfo; use Sinfo;
with Sinput; use Sinput;
with Uintp; use Uintp;
with GNAT.Byte_Order_Mark; use GNAT.Byte_Order_Mark;
with System.WCh_Con; use System.WCh_Con;
package body Scn is
use ASCII;
Used_As_Identifier : array (Token_Type) of Boolean;
-- Flags set True if a given keyword is used as an identifier (used to
-- make sure that we only post an error message for incorrect use of a
-- keyword as an identifier once for a given keyword).
procedure Check_End_Of_Line;
-- Called when end of line encountered. Checks that line is not too long,
-- and that other style checks for the end of line are met.
function Determine_License return License_Type;
-- Scan header of file and check that it has an appropriate GNAT-style
-- header with a proper license statement. Returns GPL, Unrestricted,
-- or Modified_GPL depending on header. If none of these, returns Unknown.
procedure Error_Long_Line;
-- Signal error of excessively long line
-----------------------
-- Check_End_Of_Line --
-----------------------
procedure Check_End_Of_Line is
Len : constant Int := Int (Scan_Ptr) - Int (Current_Line_Start);
begin
if Style_Check then
Style.Check_Line_Terminator (Len);
elsif Len > Max_Line_Length then
Error_Long_Line;
end if;
end Check_End_Of_Line;
-----------------------
-- Determine_License --
-----------------------
function Determine_License return License_Type is
GPL_Found : Boolean := False;
Result : License_Type;
function Contains (S : String) return Boolean;
-- See if current comment contains successive non-blank characters
-- matching the contents of S. If so leave Scan_Ptr unchanged and
-- return True, otherwise leave Scan_Ptr unchanged and return False.
procedure Skip_EOL;
-- Skip to line terminator character
--------------
-- Contains --
--------------
function Contains (S : String) return Boolean is
CP : Natural;
SP : Source_Ptr;
SS : Source_Ptr;
begin
-- Loop to check characters. This loop is terminated by end of
-- line, and also we need to check for the EOF case, to take
-- care of files containing only comments.
SP := Scan_Ptr;
while Source (SP) /= CR and then
Source (SP) /= LF and then
Source (SP) /= EOF
loop
if Source (SP) = S (S'First) then
SS := SP;
CP := S'First;
loop
SS := SS + 1;
CP := CP + 1;
if CP > S'Last then
return True;
end if;
while Source (SS) = ' ' loop
SS := SS + 1;
end loop;
exit when Source (SS) /= S (CP);
end loop;
end if;
SP := SP + 1;
end loop;
return False;
end Contains;
--------------
-- Skip_EOL --
--------------
procedure Skip_EOL is
begin
while Source (Scan_Ptr) /= CR
and then Source (Scan_Ptr) /= LF
and then Source (Scan_Ptr) /= EOF
loop
Scan_Ptr := Scan_Ptr + 1;
end loop;
end Skip_EOL;
-- Start of processing for Determine_License
begin
loop
if Source (Scan_Ptr) /= '-'
or else Source (Scan_Ptr + 1) /= '-'
then
if GPL_Found then
Result := GPL;
exit;
else
Result := Unknown;
exit;
end if;
elsif Contains ("Asaspecialexception") then
if GPL_Found then
Result := Modified_GPL;
exit;
end if;
elsif Contains ("GNUGeneralPublicLicense") then
GPL_Found := True;
elsif
Contains
("ThisspecificationisadaptedfromtheAdaSemanticInterface")
or else
Contains
("ThisspecificationisderivedfromtheAdaReferenceManual")
then
Result := Unrestricted;
exit;
end if;
Skip_EOL;
Check_End_Of_Line;
if Source (Scan_Ptr) /= EOF then
-- We have to take into account a degenerate case when the source
-- file contains only comments and no Ada code.
declare
Physical : Boolean;
begin
Skip_Line_Terminators (Scan_Ptr, Physical);
-- If we are at start of physical line, update scan pointers
-- to reflect the start of the new line.
if Physical then
Current_Line_Start := Scan_Ptr;
Start_Column := Scanner.Set_Start_Column;
First_Non_Blank_Location := Scan_Ptr;
end if;
end;
end if;
end loop;
return Result;
end Determine_License;
----------------------------
-- Determine_Token_Casing --
----------------------------
function Determine_Token_Casing return Casing_Type is
begin
return Scanner.Determine_Token_Casing;
end Determine_Token_Casing;
---------------------
-- Error_Long_Line --
---------------------
procedure Error_Long_Line is
begin
Error_Msg
("this line is too long",
Current_Line_Start + Source_Ptr (Max_Line_Length));
end Error_Long_Line;
------------------------
-- Initialize_Scanner --
------------------------
procedure Initialize_Scanner
(Unit : Unit_Number_Type;
Index : Source_File_Index)
is
GNAT_Hedr : constant Text_Buffer (1 .. 78) := (others => '-');
begin
Scanner.Initialize_Scanner (Index);
if Index /= Internal_Source_File then
Set_Unit (Index, Unit);
end if;
Current_Source_Unit := Unit;
-- Set default for Comes_From_Source (except if we are going to process
-- an artificial string internally created within the compiler and
-- placed into internal source duffer). All nodes built now until we
-- reenter the analyzer will have Comes_From_Source set to True
if Index /= Internal_Source_File then
Set_Comes_From_Source_Default (True);
end if;
-- Check license if GNAT type header possibly present
if Source_Last (Index) - Scan_Ptr > 80
and then Source (Scan_Ptr .. Scan_Ptr + 77) = GNAT_Hedr
then
Set_License (Current_Source_File, Determine_License);
end if;
-- Check for BOM
declare
BOM : BOM_Kind;
Len : Natural;
Tst : String (1 .. 5);
begin
for J in 1 .. 5 loop
Tst (J) := Source (Scan_Ptr + Source_Ptr (J) - 1);
end loop;
Read_BOM (Tst, Len, BOM, False);
case BOM is
when UTF8_All =>
Scan_Ptr := Scan_Ptr + Source_Ptr (Len);
Wide_Character_Encoding_Method := WCEM_UTF8;
Upper_Half_Encoding := True;
when UTF16_LE | UTF16_BE =>
Set_Standard_Error;
Write_Line ("UTF-16 encoding format not recognized");
Set_Standard_Output;
raise Unrecoverable_Error;
when UTF32_LE | UTF32_BE =>
Set_Standard_Error;
Write_Line ("UTF-32 encoding format not recognized");
Set_Standard_Output;
raise Unrecoverable_Error;
when Unknown =>
null;
when others =>
raise Program_Error;
end case;
end;
-- Because of the License stuff above, Scng.Initialize_Scanner cannot
-- call Scan. Scan initial token (note this initializes Prev_Token,
-- Prev_Token_Ptr).
-- There are two reasons not to do the Scan step in case if we
-- initialize the scanner for the internal source buffer:
-- - The artificial string may not be created by the compiler in this
-- buffer when we call Initialize_Scanner
-- - For these artificial strings a special way of scanning is used, so
-- the standard step of the scanner may just break the algorithm of
-- processing these strings.
if Index /= Internal_Source_File then
Scan;
end if;
-- Clear flags for reserved words used as identifiers
for J in Token_Type loop
Used_As_Identifier (J) := False;
end loop;
end Initialize_Scanner;
---------------
-- Post_Scan --
---------------
procedure Post_Scan is
procedure Check_Obsolescent_Features_Restriction (S : Source_Ptr);
-- This checks for Obsolescent_Features restriction being active, and
-- if so, flags the restriction as occurring at the given scan location.
procedure Check_Obsolete_Base_Char;
-- Check for numeric literal using ':' instead of '#' for based case
--------------------------------------------
-- Check_Obsolescent_Features_Restriction --
--------------------------------------------
procedure Check_Obsolescent_Features_Restriction (S : Source_Ptr) is
begin
-- Normally we have a node handy for posting restrictions. We don't
-- have such a node here, so construct a dummy one with the right
-- scan pointer. This is only used to get the Sloc value anyway.
Check_Restriction (No_Obsolescent_Features, New_Node (N_Empty, S));
end Check_Obsolescent_Features_Restriction;
------------------------------
-- Check_Obsolete_Base_Char --
------------------------------
procedure Check_Obsolete_Base_Char is
S : Source_Ptr;
begin
if Based_Literal_Uses_Colon then
-- Find the : for the restriction or warning message
S := Token_Ptr;
while Source (S) /= ':' loop
S := S + 1;
end loop;
Check_Obsolescent_Features_Restriction (S);
if Warn_On_Obsolescent_Feature then
Error_Msg
("use of "":"" is an obsolescent feature (RM J.2(3))?", S);
Error_Msg
("\use ""'#"" instead?", S);
end if;
end if;
end Check_Obsolete_Base_Char;
-- Start of processing for Post_Scan
begin
case Token is
when Tok_Char_Literal =>
Token_Node := New_Node (N_Character_Literal, Token_Ptr);
Set_Char_Literal_Value (Token_Node, UI_From_CC (Character_Code));
Set_Chars (Token_Node, Token_Name);
when Tok_Identifier =>
Token_Node := New_Node (N_Identifier, Token_Ptr);
Set_Chars (Token_Node, Token_Name);
when Tok_Real_Literal =>
Token_Node := New_Node (N_Real_Literal, Token_Ptr);
Set_Realval (Token_Node, Real_Literal_Value);
Check_Obsolete_Base_Char;
when Tok_Integer_Literal =>
Token_Node := New_Node (N_Integer_Literal, Token_Ptr);
Set_Intval (Token_Node, Int_Literal_Value);
Check_Obsolete_Base_Char;
when Tok_String_Literal =>
Token_Node := New_Node (N_String_Literal, Token_Ptr);
Set_Has_Wide_Character
(Token_Node, Wide_Character_Found);
Set_Has_Wide_Wide_Character
(Token_Node, Wide_Wide_Character_Found);
Set_Strval (Token_Node, String_Literal_Id);
if Source (Token_Ptr) = '%' then
Check_Obsolescent_Features_Restriction (Token_Ptr);
if Warn_On_Obsolescent_Feature then
Error_Msg_SC
("use of ""'%"" is an obsolescent feature (RM J.2(4))?");
Error_Msg_SC ("\use """""" instead?");
end if;
end if;
when Tok_Operator_Symbol =>
Token_Node := New_Node (N_Operator_Symbol, Token_Ptr);
Set_Chars (Token_Node, Token_Name);
Set_Strval (Token_Node, String_Literal_Id);
when Tok_Vertical_Bar =>
if Source (Token_Ptr) = '!' then
Check_Obsolescent_Features_Restriction (Token_Ptr);
if Warn_On_Obsolescent_Feature then
Error_Msg_SC
("use of ""'!"" is an obsolescent feature (RM J.2(2))?");
Error_Msg_SC ("\use ""'|"" instead?");
end if;
end if;
when others =>
null;
end case;
end Post_Scan;
------------------------------
-- Scan_Reserved_Identifier --
------------------------------
procedure Scan_Reserved_Identifier (Force_Msg : Boolean) is
Token_Chars : constant String := Token_Type'Image (Token);
begin
-- We have in Token_Chars the image of the Token name, i.e. Tok_xxx.
-- This code extracts the xxx and makes an identifier out of it.
Name_Len := 0;
for J in 5 .. Token_Chars'Length loop
Name_Len := Name_Len + 1;
Name_Buffer (Name_Len) := Fold_Lower (Token_Chars (J));
end loop;
Token_Name := Name_Find;
if not Used_As_Identifier (Token) or else Force_Msg then
-- If "some" is made into a reseverd work in Ada2012, the following
-- check will make it into a regular identifer in earlier versions
-- of the language.
if Token = Tok_Some and then Ada_Version < Ada_2012 then
null;
else
Error_Msg_Name_1 := Token_Name;
Error_Msg_SC ("reserved word* cannot be used as identifier!");
Used_As_Identifier (Token) := True;
end if;
end if;
Token := Tok_Identifier;
Token_Node := New_Node (N_Identifier, Token_Ptr);
Set_Chars (Token_Node, Token_Name);
end Scan_Reserved_Identifier;
end Scn;
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