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Diffstat (limited to 'gcc-4.2.1/gcc/ada/sem_maps.ads')
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diff --git a/gcc-4.2.1/gcc/ada/sem_maps.ads b/gcc-4.2.1/gcc/ada/sem_maps.ads new file mode 100644 index 000000000..eb1267906 --- /dev/null +++ b/gcc-4.2.1/gcc/ada/sem_maps.ads @@ -0,0 +1,168 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- S E M _ M A P S -- +-- -- +-- S p e c -- +-- -- +-- Copyright (C) 1996-2005, 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 2, 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 COPYING. If not, write -- +-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, -- +-- Boston, MA 02110-1301, USA. -- +-- -- +-- GNAT was originally developed by the GNAT team at New York University. -- +-- Extensive contributions were provided by Ada Core Technologies Inc. -- +-- -- +------------------------------------------------------------------------------ + +-- This package contains the operations on the renaming maps used for +-- generic analysis and instantiation. Renaming maps are created when +-- a generic unit is analyzed, in order to capture all references to +-- global variables within the unit. The renaming map of a generic unit +-- copied prior to each instantiation, and then updated by mapping the +-- formals into the actuals and the local entities into entities local to +-- the instance. When the generic tree is copied to produce the instance, +-- all references are updated by means of the renaming map. + +-- Map composition of renaming maps takes place for nested instantiations, +-- for generic child units, and for formal packages. + +-- For additional details, see the documentation in sem_ch12 + +with Table; +with Types; use Types; + +package Sem_Maps is + + type Map is new Int; + + type Assoc is private; + + type Scope_Kind is (S_Global, S_Formal, S_Local); + + function New_Map (Num_Assoc : Int) return Map; + -- Build empty map with the given number of associations, and a + -- headers table of the appropriate size. + + function Compose (Orig_Map : Map; New_Map : Map) return Map; + -- Update the associations in Orig_Map, so that if Orig_Map (e1) = e2 + -- and New_Map (e2) = e3, then the image of e1 under the result is e3. + + function Copy (M : Map) return Map; + -- Full copy of contents and headers + + function Lookup (M : Map; E : Entity_Id) return Entity_Id; + -- Retrieve image of E under M, Empty if undefined + + procedure Add_Association + (M : in out Map; + O_Id : Entity_Id; + N_Id : Entity_Id; + Kind : Scope_Kind := S_Local); + -- Update M in place. On entry M (O_Id) must not be defined + + procedure Update_Association + (M : in out Map; + O_Id : Entity_Id; + N_Id : Entity_Id; + Kind : Scope_Kind := S_Local); + -- Update the entry in M for O_Id + + function Build_Instance_Map (M : Map) return Map; + -- Copy renaming map of generic, and create new entities for all the + -- local entities within. + +private + + -- New maps are created when a generic is analyzed, and for each of + -- its instantiations. Maps are also updated for nested generics, for + -- child units, and for formal packages. As a result we need to allocate + -- maps dynamically. + + -- When analyzing a generic, we do not know how many references are + -- in it. We build an initial map after generic analysis, using a static + -- structure that relies on the compiler's extensible table mechanism. + -- After constructing this initial map, all subsequent uses and updates + -- of this map do not modify its domain, so that dynamically allocated + -- maps have a fixed size and never need to be reallocated. Furthermore, + -- the headers of the hash table of a dynamically allocated map can be + -- chosen according to the total number of entries in the map, to + -- accommodate efficiently generic units of different sizes (Unchecked_ + -- Conversion vs. Generic_Elementary_Functions, for example). So in + -- fact both components of a map have fixed size, and can be allocated + -- using the standard table mechanism. A Maps_Table holds records that + -- contain indices into the global Headers table and the Associations + -- table, and a Map is an index into the Maps_Table. + -- + -- Maps_Table Headers_Table Associations_Table + -- + -- |_____| |___________ | + -- |_____| | | | | + -- ------>|Map |------------------------------>|Associations| + -- |Info |------------->| |=========>| for one | + -- |_____| | |====| | unit | + -- | | | | |====>| | + -- |_____| |____________| + -- | | | | + type Header_Index is new Int; + type Assoc_Index is new Int; + No_Assoc : constant Assoc_Index := -1; + + type Map_Info is record + Header_Offset : Header_Index; + Header_Num : Header_Index; + Assoc_Offset : Assoc_Index; + Assoc_Num : Assoc_Index; + Assoc_Next : Assoc_Index; + end record; + + type Assoc is record + Old_Id : Entity_Id := Empty; + New_Id : Entity_Id := Empty; + Kind : Scope_Kind := S_Local; + Next : Assoc_Index := No_Assoc; + end record; + + -- All maps are accessed through the following table. The map attribute + -- of a generic unit or an instance is an index into this table. + + package Maps_Table is new Table.Table ( + Table_Component_Type => Map_Info, + Table_Index_Type => Map, + Table_Low_Bound => 0, + Table_Initial => 100, + Table_Increment => 10, + Table_Name => "Maps_Table"); + + -- All headers for hash tables are allocated in one global table. Each + -- map stores the offset into this table at which its own headers start. + + package Headers_Table is new Table.Table ( + Table_Component_Type => Assoc_Index, + Table_Index_Type => Header_Index, + Table_Low_Bound => 0, + Table_Initial => 1000, + Table_Increment => 10, + Table_Name => "Headers_Table"); + + -- All associations are allocated in one global table. Each map stores + -- the offset into this table at which its own associations start. + + package Associations_Table is new Table.Table ( + Table_Component_Type => Assoc, + Table_Index_Type => Assoc_Index, + Table_Low_Bound => 1, + Table_Initial => 1000, + Table_Increment => 10, + Table_Name => "Associations_Table"); + +end Sem_Maps; |