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------------------------------------------------------------------------------

--                                                                          --

--                         GNAT COMPILER COMPONENTS                         --

--                                                                          --

--                             E X P _ D B U G                              --

--                                                                          --

--                                 B o d y                                  --

--                                                                          --

--          Copyright (C) 1996-2011, 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 Alloc;    use Alloc;

with Atree;    use Atree;

with Debug;    use Debug;

with Einfo;    use Einfo;

with Nlists;   use Nlists;

with Nmake;    use Nmake;

with Opt;      use Opt;

with Output;   use Output;

with Sem_Aux;  use Sem_Aux;

with Sem_Eval; use Sem_Eval;

with Sem_Util; use Sem_Util;

with Sinfo;    use Sinfo;

with Stand;    use Stand;

with Stringt;  use Stringt;

with Table;

with Targparm; use Targparm;

with Tbuild;   use Tbuild;

with Urealp;   use Urealp;

package body Exp_Dbug is

   --  The following table is used to queue up the entities passed as

   --  arguments to Qualify_Entity_Names for later processing when

   --  Qualify_All_Entity_Names is called.

   package Name_Qualify_Units is new Table.Table (

     Table_Component_Type => Node_Id,

     Table_Index_Type     => Nat,

     Table_Low_Bound      => 1,

     Table_Initial        => Alloc.Name_Qualify_Units_Initial,

     Table_Increment      => Alloc.Name_Qualify_Units_Increment,

     Table_Name           => "Name_Qualify_Units");

   --------------------------------

   -- Use of Qualification Flags --

   --------------------------------

   --  There are two flags used to keep track of qualification of entities

   --    Has_Fully_Qualified_Name

   --    Has_Qualified_Name

   --  The difference between these is as follows. Has_Qualified_Name is

   --  set to indicate that the name has been qualified as required by the

   --  spec of this package. As described there, this may involve the full

   --  qualification for the name, but for some entities, notably procedure

   --  local variables, this full qualification is not required.

   --  The flag Has_Fully_Qualified_Name is set if indeed the name has been

   --  fully qualified in the Ada sense. If Has_Fully_Qualified_Name is set,

   --  then Has_Qualified_Name is also set, but the other way round is not

   --  the case.

   --  Consider the following example:

   --     with ...

   --     procedure X is

   --       B : Ddd.Ttt;

   --       procedure Y is ..

   --  Here B is a procedure local variable, so it does not need fully

   --  qualification. The flag Has_Qualified_Name will be set on the

   --  first attempt to qualify B, to indicate that the job is done

   --  and need not be redone.

   --  But Y is qualified as x__y, since procedures are always fully

   --  qualified, so the first time that an attempt is made to qualify

   --  the name y, it will be replaced by x__y, and both flags are set.

   --  Why the two flags? Well there are cases where we derive type names

   --  from object names. As noted in the spec, type names are always

   --  fully qualified. Suppose for example that the backend has to build

   --  a padded type for variable B. then it will construct the PAD name

   --  from B, but it requires full qualification, so the fully qualified

   --  type name will be x__b___PAD. The two flags allow the circuit for

   --  building this name to realize efficiently that b needs further

   --  qualification.

   --------------------

   -- Homonym_Suffix --

   --------------------

   --  The string defined here (and its associated length) is used to gather

   --  the homonym string that will be appended to Name_Buffer when the name

   --  is complete. Strip_Suffixes appends to this string as does

   --  Append_Homonym_Number, and Output_Homonym_Numbers_Suffix appends the

   --  string to the end of Name_Buffer.

   Homonym_Numbers : String (1 .. 256);

   Homonym_Len     : Natural := 0;

   ----------------------

   -- Local Procedures --

   ----------------------

   procedure Add_Uint_To_Buffer (U : Uint);

   --  Add image of universal integer to Name_Buffer, updating Name_Len

   procedure Add_Real_To_Buffer (U : Ureal);

   --  Add nnn_ddd to Name_Buffer, where nnn and ddd are integer values of

   --  the normalized numerator and denominator of the given real value.

   procedure Append_Homonym_Number (E : Entity_Id);

   --  If the entity E has homonyms in the same scope, then make an entry

   --  in the Homonym_Numbers array, bumping Homonym_Count accordingly.

   function Bounds_Match_Size (E : Entity_Id) return  Boolean;

   --  Determine whether the bounds of E match the size of the type. This is

   --  used to determine whether encoding is required for a discrete type.

   procedure Output_Homonym_Numbers_Suffix;

   --  If homonym numbers are stored, then output them into Name_Buffer

   procedure Prepend_String_To_Buffer (S : String);

   --  Prepend given string to the contents of the string buffer, updating

   --  the value in Name_Len (i.e. string is added at start of buffer).

   procedure Prepend_Uint_To_Buffer (U : Uint);

   --  Prepend image of universal integer to Name_Buffer, updating Name_Len

   procedure Qualify_Entity_Name (Ent : Entity_Id);

   --  If not already done, replaces the Chars field of the given entity

   --  with the appropriate fully qualified name.

   procedure Reset_Buffers;

   --  Reset the contents of Name_Buffer and Homonym_Numbers by setting their

   --  respective lengths to zero.

   procedure Strip_Suffixes (BNPE_Suffix_Found : in out Boolean);

   --  Given an qualified entity name in Name_Buffer, remove any plain X or

   --  X{nb} qualification suffix. The contents of Name_Buffer is not changed

   --  but Name_Len may be adjusted on return to remove the suffix. If a

   --  BNPE suffix is found and stripped, then BNPE_Suffix_Found is set to

   --  True. If no suffix is found, then BNPE_Suffix_Found is not modified.

   --  This routine also searches for a homonym suffix, and if one is found

   --  it is also stripped, and the entries are added to the global homonym

   --  list (Homonym_Numbers) so that they can later be put back.

   ------------------------

   -- Add_Real_To_Buffer --

   ------------------------

   procedure Add_Real_To_Buffer (U : Ureal) is

   begin

      Add_Uint_To_Buffer (Norm_Num (U));

      Add_Str_To_Name_Buffer ("_");

      Add_Uint_To_Buffer (Norm_Den (U));

   end Add_Real_To_Buffer;

   ------------------------

   -- Add_Uint_To_Buffer --

   ------------------------

   procedure Add_Uint_To_Buffer (U : Uint) is

   begin

      if U < 0 then

         Add_Uint_To_Buffer (-U);

         Add_Char_To_Name_Buffer ('m');

      else

         UI_Image (U, Decimal);

         Add_Str_To_Name_Buffer (UI_Image_Buffer (1 .. UI_Image_Length));

      end if;

   end Add_Uint_To_Buffer;

   ---------------------------

   -- Append_Homonym_Number --

   ---------------------------

   procedure Append_Homonym_Number (E : Entity_Id) is

      procedure Add_Nat_To_H (Nr : Nat);

      --  Little procedure to append Nr to Homonym_Numbers

      ------------------

      -- Add_Nat_To_H --

      ------------------

      procedure Add_Nat_To_H (Nr : Nat) is

      begin

         if Nr >= 10 then

            Add_Nat_To_H (Nr / 10);

         end if;

         Homonym_Len := Homonym_Len + 1;

         Homonym_Numbers (Homonym_Len) :=

           Character'Val (Nr mod 10 + Character'Pos ('0'));

      end Add_Nat_To_H;

   --  Start of processing for Append_Homonym_Number

   begin

      if Has_Homonym (E) then

         declare

            H  : Entity_Id := Homonym (E);

            Nr : Nat := 1;

         begin

            while Present (H) loop

               if Scope (H) = Scope (E) then

                  Nr := Nr + 1;

               end if;

               H := Homonym (H);

            end loop;

            if Homonym_Len > 0 then

               Homonym_Len := Homonym_Len + 1;

               Homonym_Numbers (Homonym_Len) := '_';

            end if;

            Add_Nat_To_H (Nr);

         end;

      end if;

   end Append_Homonym_Number;

   -----------------------

   -- Bounds_Match_Size --

   -----------------------

   function Bounds_Match_Size (E : Entity_Id) return Boolean is

      Siz : Uint;

   begin

      if not Is_OK_Static_Subtype (E) then

         return False;

      elsif Is_Integer_Type (E)

        and then Subtypes_Statically_Match (E, Base_Type (E))

      then

         return True;

      --  Here we check if the static bounds match the natural size, which is

      --  the size passed through with the debugging information. This is the

      --  Esize rounded up to 8, 16, 32 or 64 as appropriate.

      else

         declare

            Umark  : constant Uintp.Save_Mark := Uintp.Mark;

            Result : Boolean;

         begin

            if Esize (E) <= 8 then

               Siz := Uint_8;

            elsif Esize (E) <= 16 then

               Siz := Uint_16;

            elsif Esize (E) <= 32 then

               Siz := Uint_32;

            else

               Siz := Uint_64;

            end if;

            if Is_Modular_Integer_Type (E) or else Is_Enumeration_Type (E) then

               Result :=

                 Expr_Rep_Value (Type_Low_Bound (E)) = 0

                   and then

                 2 ** Siz - Expr_Rep_Value (Type_High_Bound (E)) = 1;

            else

               Result :=

                 Expr_Rep_Value (Type_Low_Bound (E)) + 2 ** (Siz - 1) = 0

                   and then

                 2 ** (Siz - 1) - Expr_Rep_Value (Type_High_Bound (E)) = 1;

            end if;

            Release (Umark);

            return Result;

         end;

      end if;

   end Bounds_Match_Size;

   --------------------------------

   -- Debug_Renaming_Declaration --

   --------------------------------

   function Debug_Renaming_Declaration (N : Node_Id) return Node_Id is

      Loc : constant Source_Ptr := Sloc (N);

      Ent : constant Node_Id    := Defining_Entity (N);

      Nam : constant Node_Id    := Name (N);

      Ren : Node_Id;

      Typ : Entity_Id;

      Obj : Entity_Id;

      Res : Node_Id;

      function Output_Subscript (N : Node_Id; S : String) return Boolean;

      --  Outputs a single subscript value as ?nnn (subscript is compile time

      --  known value with value nnn) or as ?e (subscript is local constant

      --  with name e), where S supplies the proper string to use for ?.

      --  Returns False if the subscript is not of an appropriate type to

      --  output in one of these two forms. The result is prepended to the

      --  name stored in Name_Buffer.

      ----------------------

      -- Output_Subscript --

      ----------------------

      function Output_Subscript (N : Node_Id; S : String) return Boolean is

      begin

         if Compile_Time_Known_Value (N) then

            Prepend_Uint_To_Buffer (Expr_Value (N));

         elsif Nkind (N) = N_Identifier

           and then Scope (Entity (N)) = Scope (Ent)

           and then Ekind (Entity (N)) = E_Constant

         then

            Prepend_String_To_Buffer (Get_Name_String (Chars (Entity (N))));

         else

            return False;

         end if;

         Prepend_String_To_Buffer (S);

         return True;

      end Output_Subscript;

   --  Start of processing for Debug_Renaming_Declaration

   begin

      if not Comes_From_Source (N)

        and then not Needs_Debug_Info (Ent)

      then

         return Empty;

      end if;

      --  Do not output those local variables in VM case, as this does not

      --  help debugging (they are just unused), and might lead to duplicated

      --  local variable names.

      if VM_Target /= No_VM then

         return Empty;

      end if;

      --  Get renamed entity and compute suffix

      Name_Len := 0;

      Ren := Nam;

      loop

         case Nkind (Ren) is

            when N_Identifier =>

               exit;

            when N_Expanded_Name =>

               --  The entity field for an N_Expanded_Name is on the expanded

               --  name node itself, so we are done here too.

               exit;

            when N_Selected_Component =>

               Prepend_String_To_Buffer

                 (Get_Name_String (Chars (Selector_Name (Ren))));

               Prepend_String_To_Buffer ("XR");

               Ren := Prefix (Ren);

            when N_Indexed_Component =>

               declare

                  X : Node_Id := Last (Expressions (Ren));

               begin

                  while Present (X) loop

                     if not Output_Subscript (X, "XS") then

                        Set_Materialize_Entity (Ent);

                        return Empty;

                     end if;

                     Prev (X);

                  end loop;

               end;

               Ren := Prefix (Ren);

            when N_Slice =>

               Typ := Etype (First_Index (Etype (Nam)));

               if not Output_Subscript (Type_High_Bound (Typ), "XS") then

                  Set_Materialize_Entity (Ent);

                  return Empty;

               end if;

               if not Output_Subscript (Type_Low_Bound  (Typ), "XL") then

                  Set_Materialize_Entity (Ent);

                  return Empty;

               end if;

               Ren := Prefix (Ren);

            when N_Explicit_Dereference =>

               Set_Materialize_Entity (Ent);

               Prepend_String_To_Buffer ("XA");

               Ren := Prefix (Ren);

            --  For now, anything else simply results in no translation

            when others =>

               Set_Materialize_Entity (Ent);

               return Empty;

         end case;

      end loop;

      Prepend_String_To_Buffer ("___XE");

      --  Include the designation of the form of renaming

      case Nkind (N) is

         when N_Object_Renaming_Declaration =>

            Prepend_String_To_Buffer ("___XR");

         when N_Exception_Renaming_Declaration =>

            Prepend_String_To_Buffer ("___XRE");

         when N_Package_Renaming_Declaration =>

            Prepend_String_To_Buffer ("___XRP");

         when others =>

            return Empty;

      end case;

      --  Add the name of the renaming entity to the front

      Prepend_String_To_Buffer (Get_Name_String (Chars (Ent)));

      --  If it is a child unit create a fully qualified name, to disambiguate

      --  multiple child units with the same name and different parents.

      if Nkind (N) = N_Package_Renaming_Declaration

        and then Is_Child_Unit (Ent)

      then

         Prepend_String_To_Buffer ("__");

         Prepend_String_To_Buffer

           (Get_Name_String (Chars (Scope (Ent))));

      end if;

      --  Create the special object whose name is the debug encoding for the

      --  renaming declaration.

      --  For now, the object name contains the suffix encoding for the renamed

      --  object, but not the name of the leading entity. The object is linked

      --  the renamed entity using the Debug_Renaming_Link field. Then the

      --  Qualify_Entity_Name procedure uses this link to create the proper

      --  fully qualified name.

      --  The reason we do things this way is that we really need to copy the

      --  qualification of the renamed entity, and it is really much easier to

      --  do this after the renamed entity has itself been fully qualified.

      Obj := Make_Defining_Identifier (Loc, Chars => Name_Enter);

      Res :=

        Make_Object_Declaration (Loc,

          Defining_Identifier => Obj,

          Object_Definition   => New_Reference_To

                                   (Standard_Debug_Renaming_Type, Loc));

      Set_Debug_Renaming_Link (Obj, Entity (Ren));

      Set_Debug_Info_Needed (Obj);

      --  Mark the object as internal so that it won't be initialized when

      --  pragma Initialize_Scalars or Normalize_Scalars is in use.

      Set_Is_Internal (Obj);

      return Res;

   --  If we get an exception, just figure it is a case that we cannot

   --  successfully handle using our current approach, since this is

   --  only for debugging, no need to take the compilation with us!

   exception

      when others =>

         return Make_Null_Statement (Loc);

   end Debug_Renaming_Declaration;

   ----------------------

   -- Get_Encoded_Name --

   ----------------------

   --  Note: see spec for details on encodings

   procedure Get_Encoded_Name (E : Entity_Id) is

      Has_Suffix : Boolean;

   begin

      --  If not generating code, there is no need to create encoded names, and

      --  problems when the back-end is called to annotate types without full

      --  code generation. See comments in Get_External_Name_With_Suffix for

      --  additional details.

      --  However we do create encoded names if the back end is active, even

      --  if Operating_Mode got reset. Otherwise any serious error reported

      --  by the backend calling Error_Msg changes the Compilation_Mode to

      --  Check_Semantics, which disables the functionality of this routine,

      --  causing the generation of spurious additional errors.

      --  Couldn't we just test Original_Operating_Mode here? ???

      if Operating_Mode /= Generate_Code

        and then not Generating_Code

      then

         return;

      end if;

      Get_Name_String (Chars (E));

      --  Nothing to do if we do not have a type

      if not Is_Type (E)

      --  Or if this is an enumeration base type

        or else (Is_Enumeration_Type (E) and then Is_Base_Type (E))

      --  Or if this is a dummy type for a renaming

        or else (Name_Len >= 3 and then

                   Name_Buffer (Name_Len - 2 .. Name_Len) = "_XR")

        or else (Name_Len >= 4 and then

                   (Name_Buffer (Name_Len - 3 .. Name_Len) = "_XRE"

                      or else

                    Name_Buffer (Name_Len - 3 .. Name_Len) = "_XRP"))

      --  For all these cases, just return the name unchanged

      then

         Name_Buffer (Name_Len + 1) := ASCII.NUL;

         return;

      end if;

      Has_Suffix := True;

      --  Fixed-point case

      if Is_Fixed_Point_Type (E) then

         Get_External_Name_With_Suffix (E, "XF_");

         Add_Real_To_Buffer (Delta_Value (E));

         if Small_Value (E) /= Delta_Value (E) then

            Add_Str_To_Name_Buffer ("_");

            Add_Real_To_Buffer (Small_Value (E));

         end if;

      --  Vax floating-point case

      elsif Vax_Float (E) then

         if Digits_Value (Base_Type (E)) = 6 then

            Get_External_Name_With_Suffix (E, "XFF");

         elsif Digits_Value (Base_Type (E)) = 9 then

            Get_External_Name_With_Suffix (E, "XFF");

         else

            pragma Assert (Digits_Value (Base_Type (E)) = 15);

            Get_External_Name_With_Suffix (E, "XFG");

         end if;

      --  Discrete case where bounds do not match size

      elsif Is_Discrete_Type (E)

        and then not Bounds_Match_Size (E)

      then

         declare

            Lo : constant Node_Id := Type_Low_Bound (E);

            Hi : constant Node_Id := Type_High_Bound (E);

            Lo_Con : constant Boolean := Compile_Time_Known_Value (Lo);

            Hi_Con : constant Boolean := Compile_Time_Known_Value (Hi);

            Lo_Discr : constant Boolean :=

                         Nkind (Lo) = N_Identifier

                           and then

                         Ekind (Entity (Lo)) = E_Discriminant;

            Hi_Discr : constant Boolean :=

                         Nkind (Hi) = N_Identifier

                           and then

                         Ekind (Entity (Hi)) = E_Discriminant;

            Lo_Encode : constant Boolean := Lo_Con or Lo_Discr;

            Hi_Encode : constant Boolean := Hi_Con or Hi_Discr;

            Biased : constant Boolean := Has_Biased_Representation (E);

         begin

            if Biased then

               Get_External_Name_With_Suffix (E, "XB");

            else

               Get_External_Name_With_Suffix (E, "XD");

            end if;

            if Lo_Encode or Hi_Encode then

               if Biased then

                  Add_Str_To_Name_Buffer ("_");

               else

                  if Lo_Encode then

                     if Hi_Encode then

                        Add_Str_To_Name_Buffer ("LU_");

                     else

                        Add_Str_To_Name_Buffer ("L_");

                     end if;

                  else

                     Add_Str_To_Name_Buffer ("U_");

                  end if;

               end if;

               if Lo_Con then

                  Add_Uint_To_Buffer (Expr_Rep_Value (Lo));

               elsif Lo_Discr then

                  Get_Name_String_And_Append (Chars (Entity (Lo)));

               end if;

               if Lo_Encode and Hi_Encode then

                  Add_Str_To_Name_Buffer ("__");

               end if;

               if Hi_Con then

                  Add_Uint_To_Buffer (Expr_Rep_Value (Hi));

               elsif Hi_Discr then

                  Get_Name_String_And_Append (Chars (Entity (Hi)));

               end if;

            end if;

         end;

      --  For all other cases, the encoded name is the normal type name

      else

         Has_Suffix := False;

         Get_External_Name (E, Has_Suffix);

      end if;

      if Debug_Flag_B and then Has_Suffix then

         Write_Str ("**** type ");

         Write_Name (Chars (E));

         Write_Str (" is encoded as ");

         Write_Str (Name_Buffer (1 .. Name_Len));

         Write_Eol;

      end if;

      Name_Buffer (Name_Len + 1) := ASCII.NUL;

   end Get_Encoded_Name;

   -----------------------

   -- Get_External_Name --

   -----------------------

   procedure Get_External_Name (Entity : Entity_Id; Has_Suffix : Boolean) is

      E    : Entity_Id := Entity;

      Kind : Entity_Kind;

      procedure Get_Qualified_Name_And_Append (Entity : Entity_Id);

      --  Appends fully qualified name of given entity to Name_Buffer

      -----------------------------------

      -- Get_Qualified_Name_And_Append --

      -----------------------------------

      procedure Get_Qualified_Name_And_Append (Entity : Entity_Id) is

      begin

         --  If the entity is a compilation unit, its scope is Standard,

         --  there is no outer scope, and the no further qualification

         --  is required.

         --  If the front end has already computed a fully qualified name,

         --  then it is also the case that no further qualification is

         --  required.

         if Present (Scope (Scope (Entity)))

           and then not Has_Fully_Qualified_Name (Entity)

         then

            Get_Qualified_Name_And_Append (Scope (Entity));

            Add_Str_To_Name_Buffer ("__");

            Get_Name_String_And_Append (Chars (Entity));

            Append_Homonym_Number (Entity);

         else

            Get_Name_String_And_Append (Chars (Entity));

         end if;

      end Get_Qualified_Name_And_Append;

   --  Start of processing for Get_External_Name

   begin

      Reset_Buffers;

      --  If this is a child unit, we want the child

      if Nkind (E) = N_Defining_Program_Unit_Name then

         E := Defining_Identifier (Entity);

      end if;

      Kind := Ekind (E);

      --  Case of interface name being used

      if (Kind = E_Procedure or else

          Kind = E_Function  or else

          Kind = E_Constant  or else

          Kind = E_Variable  or else

          Kind = E_Exception)

        and then Present (Interface_Name (E))

        and then No (Address_Clause (E))

        and then not Has_Suffix

      then

         Add_String_To_Name_Buffer (Strval (Interface_Name (E)));

      --  All other cases besides the interface name case

      else

         --  If this is a library level subprogram (i.e. a subprogram that is a

         --  compilation unit other than a subunit), then we prepend _ada_ to

         --  ensure distinctions required as described in the spec.

         --  Check explicitly for child units, because those are not flagged

         --  as Compilation_Units by lib. Should they be ???

         if Is_Subprogram (E)

           and then (Is_Compilation_Unit (E) or Is_Child_Unit (E))

           and then not Has_Suffix

         then

            Add_Str_To_Name_Buffer ("_ada_");

         end if;

         --  If the entity is a subprogram instance that is not a compilation

         --  unit, generate the name of the original Ada entity, which is the

         --  one gdb needs.

         if Is_Generic_Instance (E)

           and then Is_Subprogram (E)

           and then not Is_Compilation_Unit (Scope (E))

           and then (Ekind (Scope (E)) = E_Package

                      or else

                     Ekind (Scope (E)) = E_Package_Body)

           and then Present (Related_Instance (Scope (E)))

         then

            E := Related_Instance (Scope (E));

         end if;

         Get_Qualified_Name_And_Append (E);

      end if;

      Name_Buffer (Name_Len + 1) := ASCII.NUL;