------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- P P R I N T --
-- --
-- B o d y --
-- --
-- Copyright (C) 2008-2025, 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 Einfo; use Einfo;
with Einfo.Entities; use Einfo.Entities;
with Einfo.Utils; use Einfo.Utils;
with Errout; use Errout;
with Namet; use Namet;
with Nlists; use Nlists;
with Opt; use Opt;
with Sinfo; use Sinfo;
with Sinfo.Nodes; use Sinfo.Nodes;
with Sinfo.Utils; use Sinfo.Utils;
with Sinput; use Sinput;
with Snames; use Snames;
with Uintp; use Uintp;
with System.Case_Util;
package body Pprint is
List_Name_Count : Natural := 0;
-- Counter used to prevent infinite recursion while computing name of
-- complex expressions.
----------------------
-- Expression_Image --
----------------------
function Expression_Image
(Expr : Node_Id;
Default : String) return String
is
function Expr_Name
(Expr : Node_Id;
Take_Prefix : Boolean := True;
Expand_Type : Boolean := True;
No_Parens : Boolean := False) return String;
-- Return string corresponding to Expr. If no string can be extracted,
-- return "...". If Take_Prefix is True, go back to prefix when needed,
-- otherwise only consider the right-hand side of an expression. If
-- Expand_Type is True and Expr is a type, try to expand Expr (an
-- internally generated type) into a user understandable name.
-- If No_Parens is True, then suppress creating parentheses around
-- expression. If False, check to see whether expression should be
-- parenthesized.
function Count_Parentheses (S : String; C : Character) return Natural
with Pre => C in '(' | ')';
-- Returns the number of times parenthesis character C should be added
-- to string S for getting a correctly parenthesized result. For C = '('
-- this means prepending the character, for C = ')' this means appending
-- the character.
-- In other words, count the number of missing instances of C,
-- but never return less than zero.
function Fix_Parentheses (S : String) return String;
-- Counts the number of required opening and closing parentheses in S to
-- respectively prepend and append for getting correct parentheses. Then
-- returns S with opening parentheses prepended and closing parentheses
-- appended so that the result is correctly parenthesized.
Max_List_Depth : constant := 3;
-- Limit number of nested lists to print
Max_List_Length : constant := 3;
-- Limit number of list elements to print
Max_Expr_Elements : constant := 24;
-- Limit number of elements in an expression for use by Expr_Name
Num_Elements : Natural := 0;
-- Current number of elements processed by Expr_Name
function List_Name (List : List_Id) return String;
-- Return a string corresponding to List
---------------
-- List_Name --
---------------
function List_Name (List : List_Id) return String is
Buf : Bounded_String;
Elmt : Node_Id;
Printed_Elmts : Natural := 0;
List_Len : constant Natural := Natural (List_Length (List));
begin
-- Give up if the printed list is too deep
if List_Name_Count > Max_List_Depth then
return "...";
end if;
List_Name_Count := List_Name_Count + 1;
Elmt := First (List);
while Present (Elmt) loop
-- Print component_association as "x | y | z => 12345"
if Nkind (Elmt) = N_Component_Association then
declare
Choice : Node_Id := First (Choices (Elmt));
begin
while Present (Choice) loop
Append (Buf, Expr_Name (Choice));
Next (Choice);
if Present (Choice) then
Append (Buf, " | ");
end if;
end loop;
end;
Append (Buf, " => ");
if Box_Present (Elmt) then
Append (Buf, "<>");
else
Append (Buf, Expr_Name (Expression (Elmt)));
end if;
-- Print parameter_association as "x => 12345"
elsif Nkind (Elmt) = N_Parameter_Association then
Append (Buf, Expr_Name (Selector_Name (Elmt)));
Append (Buf, " => ");
Append (Buf, Expr_Name (Explicit_Actual_Parameter (Elmt)));
-- Print expression itself as "12345"
else
-- Suppress parens if is the only parameter
Append (Buf, Expr_Name (Elmt, No_Parens => List_Len = 1));
end if;
Next (Elmt);
Printed_Elmts := Printed_Elmts + 1;
-- Separate next element with a comma, if necessary
if Present (Elmt) then
Append (Buf, ", ");
-- Abbreviate remaining elements as "...", if limit exceeded
if Printed_Elmts = Max_List_Length then
Append (Buf, "...");
exit;
end if;
end if;
end loop;
List_Name_Count := List_Name_Count - 1;
return To_String (Buf);
end List_Name;
---------------
-- Expr_Name --
---------------
function Expr_Name
(Expr : Node_Id;
Take_Prefix : Boolean := True;
Expand_Type : Boolean := True;
No_Parens : Boolean := False) return String
is
-- Define a subtype matching logical operations
-- and [then], or [else], and xor.
-- In Ada, these operations are non associative -- they
-- all have the same precedence, so parentheses
-- are needed to indicate the association of
-- operands in a sequence of distinct operations.
subtype Non_Associative is N_Subexpr
with Static_Predicate =>
Non_Associative in
N_Short_Circuit | N_Op_And | N_Op_Or | N_Op_Xor;
begin
if not No_Parens
and then
(Paren_Count (Expr) > 0
or else
(Nkind (Expr) in Non_Associative
and then
Nkind (Parent (Expr)) in Non_Associative
and then
Nkind (Parent (Expr)) /= Nkind (Expr)))
then
-- Parentheses are needed, either because
-- Paren_Count is greater than zero, or because
-- this operation and its parent are non associative,
-- and are not the same operation.
return '(' &
Expr_Name (Expr, Take_Prefix, Expand_Type, No_Parens => True) &
')';
end if;
Num_Elements := Num_Elements + 1;
if Num_Elements > Max_Expr_Elements then
return "...";
end if;
-- Just print pieces of aggregate nodes, even though they are not
-- expressions. It is too much trouble to handle them any better.
if Nkind (Expr) = N_Component_Association then
pragma Assert (Box_Present (Expr));
declare
Buf : Bounded_String;
Choice : Node_Id := First (Choices (Expr));
begin
while Present (Choice) loop
Append (Buf, Expr_Name (Choice));
Next (Choice);
if Present (Choice) then
Append (Buf, " | ");
end if;
end loop;
Append (Buf, " => <>");
return To_String (Buf);
end;
elsif Nkind (Expr) = N_Others_Choice then
return "others";
end if;
case N_Subexpr'(Nkind (Expr)) is
when N_Identifier =>
return Ident_Image (Expr, Expression_Image.Expr, Expand_Type);
when N_Character_Literal =>
declare
Char : constant Int := UI_To_Int (Char_Literal_Value (Expr));
begin
if Char in 32 .. 126 then
return "'" & Character'Val (Char) & "'";
else
UI_Image (Char_Literal_Value (Expr));
return
"'\" & UI_Image_Buffer (1 .. UI_Image_Length) & "'";
end if;
end;
when N_Integer_Literal =>
return UI_Image (Intval (Expr));
when N_Real_Literal =>
return Real_Image (Realval (Expr));
when N_String_Literal =>
return String_Image (Strval (Expr));
when N_Allocator =>
return "new " & Expr_Name (Expression (Expr));
when N_Aggregate =>
if Present (Expressions (Expr)) then
return '(' & List_Name (Expressions (Expr)) & ')';
-- Do not return empty string for (others => <>) aggregate
-- of a componentless record type. At least one caller (the
-- recursive call below in the N_Qualified_Expression case)
-- is not prepared to deal with a zero-length result.
elsif Null_Record_Present (Expr)
or else No (First (Component_Associations (Expr)))
then
return ("(null record)");
else
return '(' & List_Name (Component_Associations (Expr)) & ')';
end if;
when N_Extension_Aggregate =>
return '(' & Expr_Name (Ancestor_Part (Expr))
& " with (" & List_Name (Expressions (Expr)) & ')';
when N_Attribute_Reference =>
if Take_Prefix then
declare
Id : constant Attribute_Id :=
Get_Attribute_Id (Attribute_Name (Expr));
-- Always use mixed case for attributes
Str : constant String :=
Expr_Name (Prefix (Expr))
& "'"
& System.Case_Util.To_Mixed
(Get_Name_String (Attribute_Name (Expr)));
N : Node_Id;
Ranges : List_Id;
begin
if (Id = Attribute_First or else Id = Attribute_Last)
and then Str (Str'First) = '$'
then
N := Associated_Node_For_Itype (Etype (Prefix (Expr)));
if Present (N) then
if Nkind (N) = N_Full_Type_Declaration then
N := Type_Definition (N);
end if;
if Nkind (N) = N_Subtype_Declaration then
Ranges :=
Constraints
(Constraint (Subtype_Indication (N)));
if List_Length (Ranges) = 1
and then Nkind (First (Ranges)) in
N_Range |
N_Real_Range_Specification |
N_Signed_Integer_Type_Definition
then
if Id = Attribute_First then
return
Expression_Image
(Low_Bound (First (Ranges)), Str);
else
return
Expression_Image
(High_Bound (First (Ranges)), Str);
end if;
end if;
end if;
end if;
end if;
return Str;
end;
else
return ''' & Get_Name_String (Attribute_Name (Expr));
end if;
when N_Explicit_Dereference =>
Explicit_Dereference : declare
function Deref_Suffix return String;
-- Usually returns ".all", but will return "" if
-- Hide_Temp_Derefs is true and the prefix is a use of a
-- not-from-source object declared as
-- X : constant Some_Access_Type := Some_Expr'Reference;
-- (as is sometimes done in Exp_Util.Remove_Side_Effects).
------------------
-- Deref_Suffix --
------------------
function Deref_Suffix return String is
Decl : Node_Id;
begin
if Hide_Temp_Derefs
and then Nkind (Prefix (Expr)) = N_Identifier
and then Nkind (Entity (Prefix (Expr))) =
N_Defining_Identifier
then
Decl := Parent (Entity (Prefix (Expr)));
if Present (Decl)
and then Nkind (Decl) = N_Object_Declaration
and then not Comes_From_Source (Decl)
and then Constant_Present (Decl)
and then Present (Expression (Decl))
and then Nkind (Expression (Decl)) = N_Reference
then
return "";
end if;
end if;
-- The default case
return ".all";
end Deref_Suffix;
-- Start of processing for Explicit_Dereference
begin
if Hide_Parameter_Blocks
and then Nkind (Prefix (Expr)) = N_Selected_Component
and then Present (Etype (Prefix (Expr)))
and then Is_Access_Type (Etype (Prefix (Expr)))
and then Is_Param_Block_Component_Type
(Etype (Prefix (Expr)))
then
-- Return "Foo" instead of "Parameter_Block.Foo.all"
return Expr_Name (Selector_Name (Prefix (Expr)));
elsif Take_Prefix then
return Expr_Name (Prefix (Expr)) & Deref_Suffix;
else
return Deref_Suffix;
end if;
end Explicit_Dereference;
when N_Expanded_Name
| N_Selected_Component
=>
if Take_Prefix then
return
Expr_Name (Prefix (Expr)) & "." &
Expr_Name (Selector_Name (Expr));
else
return "." & Expr_Name (Selector_Name (Expr));
end if;
when N_If_Expression =>
declare
Cond_Expr : constant Node_Id := First (Expressions (Expr));
Then_Expr : constant Node_Id := Next (Cond_Expr);
Else_Expr : constant Node_Id := Next (Then_Expr);
begin
return
"if " & Expr_Name (Cond_Expr) & " then "
& Expr_Name (Then_Expr) & " else "
& Expr_Name (Else_Expr);
end;
when N_Qualified_Expression =>
declare
Mark : constant String :=
Expr_Name
(Subtype_Mark (Expr), Expand_Type => False);
Str : constant String := Expr_Name (Expression (Expr));
begin
if Str (Str'First) = '(' and then Str (Str'Last) = ')' then
return Mark & "'" & Str;
else
return Mark & "'(" & Str & ")";
end if;
end;
when N_Expression_With_Actions =>
return Expr_Name (Expression (Expr));
when N_Raise_Constraint_Error =>
if Present (Condition (Expr)) then
return
"[constraint_error when "
& Expr_Name (Condition (Expr)) & "]";
else
return "[constraint_error]";
end if;
when N_Raise_Program_Error =>
if Present (Condition (Expr)) then
return
"[program_error when "
& Expr_Name (Condition (Expr)) & "]";
else
return "[program_error]";
end if;
when N_Raise_Storage_Error =>
if Present (Condition (Expr)) then
return
"[storage_error when "
& Expr_Name (Condition (Expr)) & "]";
else
return "[storage_error]";
end if;
when N_Range =>
return
Expr_Name (Low_Bound (Expr)) & ".." &
Expr_Name (High_Bound (Expr));
when N_Slice =>
return
Expr_Name (Prefix (Expr)) & " (" &
Expr_Name (Discrete_Range (Expr)) & ")";
when N_And_Then =>
return
Expr_Name (Left_Opnd (Expr)) & " and then " &
Expr_Name (Right_Opnd (Expr));
when N_In =>
return
Expr_Name (Left_Opnd (Expr)) & " in " &
Expr_Name (Right_Opnd (Expr));
when N_Not_In =>
return
Expr_Name (Left_Opnd (Expr)) & " not in " &
Expr_Name (Right_Opnd (Expr));
when N_Or_Else =>
return
Expr_Name (Left_Opnd (Expr)) & " or else " &
Expr_Name (Right_Opnd (Expr));
when N_Op_And =>
return
Expr_Name (Left_Opnd (Expr)) & " and " &
Expr_Name (Right_Opnd (Expr));
when N_Op_Or =>
return
Expr_Name (Left_Opnd (Expr)) & " or " &
Expr_Name (Right_Opnd (Expr));
when N_Op_Xor =>
return
Expr_Name (Left_Opnd (Expr)) & " xor " &
Expr_Name (Right_Opnd (Expr));
when N_Op_Eq =>
return
Expr_Name (Left_Opnd (Expr)) & " = " &
Expr_Name (Right_Opnd (Expr));
when N_Op_Ne =>
return
Expr_Name (Left_Opnd (Expr)) & " /= " &
Expr_Name (Right_Opnd (Expr));
when N_Op_Lt =>
return
Expr_Name (Left_Opnd (Expr)) & " < " &
Expr_Name (Right_Opnd (Expr));
when N_Op_Le =>
return
Expr_Name (Left_Opnd (Expr)) & " <= " &
Expr_Name (Right_Opnd (Expr));
when N_Op_Gt =>
return
Expr_Name (Left_Opnd (Expr)) & " > " &
Expr_Name (Right_Opnd (Expr));
when N_Op_Ge =>
return
Expr_Name (Left_Opnd (Expr)) & " >= " &
Expr_Name (Right_Opnd (Expr));
when N_Op_Add =>
return
Expr_Name (Left_Opnd (Expr)) & " + " &
Expr_Name (Right_Opnd (Expr));
when N_Op_Subtract =>
return
Expr_Name (Left_Opnd (Expr)) & " - " &
Expr_Name (Right_Opnd (Expr));
when N_Op_Multiply =>
return
Expr_Name (Left_Opnd (Expr)) & " * " &
Expr_Name (Right_Opnd (Expr));
when N_Op_Divide =>
return
Expr_Name (Left_Opnd (Expr)) & " / " &
Expr_Name (Right_Opnd (Expr));
when N_Op_Mod =>
return
Expr_Name (Left_Opnd (Expr)) & " mod " &
Expr_Name (Right_Opnd (Expr));
when N_Op_Rem =>
return
Expr_Name (Left_Opnd (Expr)) & " rem " &
Expr_Name (Right_Opnd (Expr));
when N_Op_Expon =>
return
Expr_Name (Left_Opnd (Expr)) & " ** " &
Expr_Name (Right_Opnd (Expr));
when N_Op_Shift_Left =>
return
Expr_Name (Left_Opnd (Expr)) & " << " &
Expr_Name (Right_Opnd (Expr));
when N_Op_Shift_Right | N_Op_Shift_Right_Arithmetic =>
return
Expr_Name (Left_Opnd (Expr)) & " >> " &
Expr_Name (Right_Opnd (Expr));
when N_Op_Concat =>
return
Expr_Name (Left_Opnd (Expr)) & " & " &
Expr_Name (Right_Opnd (Expr));
when N_Op_Plus =>
return "+" & Expr_Name (Right_Opnd (Expr));
when N_Op_Minus =>
return "-" & Expr_Name (Right_Opnd (Expr));
when N_Op_Abs =>
return "abs " & Expr_Name (Right_Opnd (Expr));
when N_Op_Not =>
return "not (" &
Expr_Name (Right_Opnd (Expr), No_Parens => True) &
")";
when N_Type_Conversion =>
-- Most conversions are not very interesting (used inside
-- expanded checks to convert to larger ranges), so skip them.
return Expr_Name (Expression (Expr));
when N_Unchecked_Type_Conversion =>
-- Only keep the type conversion in complex cases
if not Is_Scalar_Type (Etype (Expr))
or else not Is_Scalar_Type (Etype (Expression (Expr)))
or else Is_Modular_Integer_Type (Etype (Expr)) /=
Is_Modular_Integer_Type (Etype (Expression (Expr)))
then
return Expr_Name (Subtype_Mark (Expr)) &
"(" &
Expr_Name (Expression (Expr), No_Parens => True) &
")";
else
return Expr_Name (Expression (Expr));
end if;
when N_Indexed_Component =>
if Take_Prefix then
return
Expr_Name (Prefix (Expr))
& " (" & List_Name (Expressions (Expr)) & ')';
else
return List_Name (Expressions (Expr));
end if;
when N_Function_Call =>
-- If Default = "", it means we're expanding the name of
-- a gnat temporary (and not really a function call), so add
-- parentheses around function call to mark it specially.
if Default = "" then
if Present (Parameter_Associations (Expr)) then
return '('
& Expr_Name (Name (Expr))
& " ("
& List_Name (Parameter_Associations (Expr))
& "))";
else
return '(' &
Expr_Name (Name (Expr), No_Parens => True) &
')';
end if;
elsif Present (Parameter_Associations (Expr)) then
return
Expr_Name (Name (Expr))
& " (" & List_Name (Parameter_Associations (Expr)) & ')';
else
return Expr_Name (Name (Expr));
end if;
when N_Null =>
return "null";
when N_Case_Expression
| N_Delta_Aggregate
| N_External_Initializer
| N_Interpolated_String_Literal
| N_Op_Rotate_Left
| N_Op_Rotate_Right
| N_Operator_Symbol
| N_Procedure_Call_Statement
| N_Quantified_Expression
| N_Raise_Expression
| N_Reference
| N_Target_Name
=>
return "...";
end case;
end Expr_Name;
-----------------------
-- Count_Parentheses --
-----------------------
function Count_Parentheses (S : String; C : Character) return Natural is
procedure Next_Char (Count : in out Natural; C, D, Ch : Character);
-- Process next character Ch and update the number Count of C
-- characters to add for correct parenthesizing, where D is the
-- opposite parenthesis.
-- In other words, count the number of missing instances of C,
-- or equivalently, the number of unmatched instances of D.
---------------
-- Next_Char --
---------------
procedure Next_Char (Count : in out Natural; C, D, Ch : Character) is
begin
if Ch = D then
Count := Count + 1;
elsif Ch = C and then Count > 0 then
Count := Count - 1;
end if;
end Next_Char;
-- Local variables
Count : Natural := 0;
-- Start of processing for Count_Parentheses
begin
if C = '(' then
for Ch of reverse S loop
Next_Char (Count, C, ')', Ch);
end loop;
else
for Ch of S loop
Next_Char (Count, C, '(', Ch);
end loop;
end if;
return Count;
end Count_Parentheses;
---------------------
-- Fix_Parentheses --
---------------------
function Fix_Parentheses (S : String) return String is
Count_Open : constant Natural := Count_Parentheses (S, '(');
Count_Close : constant Natural := Count_Parentheses (S, ')');
begin
return (1 .. Count_Open => '(') & S & (1 .. Count_Close => ')');
end Fix_Parentheses;
-- Local variables
Left, Right : Source_Ptr;
-- Start of processing for Expression_Image
begin
-- Since this is an expression pretty-printer, it should not be called
-- for anything but an expression. However, currently CodePeer calls
-- it for defining identifiers. This should be fixed in the CodePeer
-- itself, but for now simply return the default (if present) or print
-- name of the defining identifier.
if Nkind (Expr) = N_Defining_Identifier then
pragma Assert (CodePeer_Mode);
if Comes_From_Source (Expr)
or else Opt.Debug_Generated_Code
then
if Default = "" then
declare
Nam : constant Name_Id := Chars (Expr);
Buf : Bounded_String
(Max_Length => Natural (Length_Of_Name (Nam)));
begin
Adjust_Name_Case (Buf, Sloc (Expr));
Append (Buf, Nam);
return To_String (Buf);
end;
else
return Default;
end if;
else
declare
S : constant String :=
Ident_Image
(Expr => Expr, Orig_Expr => Expr, Expand_Type => True);
begin
if S = "..." then
return Default;
else
return S;
end if;
end;
end if;
else
pragma Assert (Nkind (Expr) in N_Subexpr);
end if;
-- ??? The following should be primarily needed for CodePeer
if not Comes_From_Source (Expr)
or else Opt.Debug_Generated_Code
then
declare
S : constant String := Expr_Name (Expr, No_Parens => True);
begin
if S = "..." then
return Default;
else
return S;
end if;
end;
end if;
-- Reach to the underlying expression for an expression-with-actions
if Nkind (Expr) = N_Expression_With_Actions then
return Expression_Image (Expression (Expr), Default);
end if;
-- Compute left (start) and right (end) slocs for the expression
Left := First_Sloc (Expr);
Right := Last_Sloc (Expr);
if Left > Right then
return Default;
end if;
declare
Scn : Source_Ptr := Left;
Src : constant not null Source_Buffer_Ptr :=
Source_Text (Get_Source_File_Index (Scn));
Threshold : constant := 256;
Buffer : String (1 .. Natural (Right - Left + 1));
Index : Natural := 0;
Skipping_Comment : Boolean := False;
Underscore : Boolean := False;
begin
while Scn <= Right loop
case Src (Scn) is
-- Give up on non ASCII characters
when Character'Val (128) .. Character'Last =>
Index := 0;
exit;
when ' '
| ASCII.HT
=>
if not Skipping_Comment and then not Underscore then
Underscore := True;
Index := Index + 1;
Buffer (Index) := ' ';
end if;
-- CR/LF/FF is the end of any comment
when ASCII.CR
| ASCII.FF
| ASCII.LF
=>
Skipping_Comment := False;
when others =>
Underscore := False;
if not Skipping_Comment then
-- Ignore comment
if Src (Scn) = '-' and then Src (Scn + 1) = '-' then
Skipping_Comment := True;
else
Index := Index + 1;
Buffer (Index) := Src (Scn);
end if;
end if;
end case;
-- Give up on too long strings
if Index >= Threshold then
return Buffer (1 .. Index) & "...";
end if;
Scn := Scn + 1;
end loop;
return Fix_Parentheses (Buffer (1 .. Index));
end;
end Expression_Image;
end Pprint;