scans.ads: New token At_Sign.

2017-01-23  Ed Schonberg  <schonberg@adacore.com>

	* scans.ads: New token At_Sign. Remove '@' from list of illegal
	characters for future version of the language. '@' is legal name.
	* scng.ads, scng.adb (Scan):  Handle '@' appropriately.
	* scn.adb (Scan_Reserved_Identifier): An occurrence of '@'
	denotes a Target_Name.
	* par-ch4.adb (P_Name, P_Primary): Handle Target_Name.
	* sinfo.ads, sinfo.adb (N_Target_Name): New non-terminal node.
	(Has_Target_Names): New flag on N_Assignment_Statement, to
	indicate that RHS has occurrences of N_Target_Name.
	* sem.adb: Call Analyze_Target_Name.
	* sem_ch5.ads, sem_ch5.adb (Analyze_Target_Name): New subpogram.
	(urrent_LHS): Global variable that denotes LHS of assignment,
	used in the analysis of Target_Name nodes.
	* sem_res.adb (Resolve_Target_Name): New procedure.
	* exp_ch5.adb (Expand_Assign_With_Target_Names): (AI12-0125):
	N is an assignment statement whose RHS contains occurences of @
	that designate the value of the LHS of the assignment. If the
	LHS is side-effect free the target names can be replaced with
	a copy of the LHS; otherwise the semantics of the assignment
	is described in terms of a procedure with an in-out parameter,
	and expanded as such.
	(Expand_N_Assignment_Statement): Call
	Expand_Assign_With_Target_Names when needed.
	* exp_util.adb (Insert_Actions): Take into account N_Target_Name.
	* sprint.adb: Handle N_Target_Name.

From-SVN: r244783

1 files changed, 16 insertions, 5 deletions

diff --git a/gcc/ada/scans.ads b/gcc/ada/scans.ads
index afbdf96..8ff3f9d 100644
--- a/gcc/ada/scans.ads
+++ b/gcc/ada/scans.ads
@@ -61,6 +61,8 @@ package Scans is
 
       Tok_Identifier,      -- identifier   Name, Lit_Or_Name, Desig
 
+      Tok_At_Sign,         -- @  AI12-0125-3 : target name
+
       Tok_Double_Asterisk, -- **
 
       Tok_Ampersand,       -- &            Binary_Addop
@@ -213,8 +215,10 @@ package Scans is
       --  also when scanning project files (where it is needed because of ???)
 
       Tok_Special,
-      --  Used only in preprocessor scanning (to represent one of the
-      --  characters '#', '$', '?', '@', '`', '\', '^', '~', or '_'. The
+      --  AI12-0125-03 : target name as abbreviation for LHS
+
+      --  Otherwise used only in preprocessor scanning (to represent one of
+      --  the characters '#', '$', '?', '@', '`', '\', '^', '~', or '_'. The
       --  character value itself is stored in Scans.Special_Character.
 
       Tok_SPARK_Hide,
@@ -269,12 +273,13 @@ package Scans is
    --  of Pascal style not equal operator).
 
    subtype Token_Class_Name is
-     Token_Type range Tok_Char_Literal .. Tok_Identifier;
+   Token_Type range Tok_Char_Literal .. Tok_At_Sign;
    --  First token of name (4.1),
    --    (identifier, char literal, operator symbol)
+   --  Includes '@' after Ada2012 corrigendum.
 
    subtype Token_Class_Desig is
-     Token_Type range Tok_Operator_Symbol .. Tok_Identifier;
+     Token_Type range Tok_Operator_Symbol .. Tok_At_Sign;
    --  Token which can be a Designator (identifier, operator symbol)
 
    subtype Token_Class_Namext is
@@ -397,6 +402,11 @@ package Scans is
    --  file being compiled. This CRC includes only program tokens, and
    --  excludes comments.
 
+   Limited_Checksum : Word := 0;
+   --  Used to accumulate a CRC representing significant tokens in the
+   --  limited view of a package, i.e. visible type names and related
+   --  tagged indicators.
+
    First_Non_Blank_Location : Source_Ptr := No_Location; -- init for -gnatVa
    --  Location of first non-blank character on the line containing the
    --  current token (i.e. the location of the character whose column number
@@ -461,8 +471,9 @@ package Scans is
    --  Wide_Character).
 
    Special_Character : Character;
+   --  AI12-0125-03 : '@' as target name is handled elsewhere.
    --  Valid only when Token = Tok_Special. Returns one of the characters
-   --  '#', '$', '?', '@', '`', '\', '^', '~', or '_'.
+   --  '#', '$', '?', '`', '\', '^', '~', or '_'.
    --
    --  Why only this set? What about wide characters???