gcc/ada/alfa.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                                 A L F A                                  --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 2011-2012, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 3,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT; see file COPYING3.  If not, go to --
  19 -- http://www.gnu.org/licenses for a complete copy of the license.          --
  20 --                                                                          --
  21 -- GNAT was originally developed  by the GNAT team at  New York University. --
  22 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  23 --                                                                          --
  24 ------------------------------------------------------------------------------
  25
  26 --  This package defines tables used to store information needed for the Alfa
  27 --  mode. It is used by procedures in Lib.Xref.Alfa to build the Alfa
  28 --  information before writing it out to the ALI file, and by Get_Alfa/Put_Alfa
  29 --  to read and write the text form that is used in the ALI file.
  30
  31 with Types;      use Types;
  32 with GNAT.Table;
  33
  34 package Alfa is
  35
  36    --  Alfa information can exist in one of two forms. In the ALI file, it is
  37    --  represented using a text format that is described in this specification.
  38    --  Internally it is stored using three tables Alfa_Xref_Table,
  39    --  Alfa_Scope_Table and Alfa_File_Table, which are also defined in this
  40    --  unit.
  41
  42    --  Lib.Xref.Alfa is part of the compiler. It extracts Alfa information from
  43    --  the complete set of cross-references generated during compilation.
  44
  45    --  Get_Alfa reads the text lines in ALI format and populates the internal
  46    --  tables with corresponding information.
  47
  48    --  Put_Alfa reads the internal tables and generates text lines in the ALI
  49    --  format.
  50
  51    ---------------------
  52    -- Alfa ALI Format --
  53    ---------------------
  54
  55    --  Alfa information is generated on a unit-by-unit basis in the ALI file,
  56    --  using lines that start with the identifying character F ("Formal").
  57    --  These lines are generated if one of the -gnatd.E (SPARK generation mode)
  58    --  or gnatd.F (Why generation mode) switches is set.
  59
  60    --  The Alfa information follows the cross-reference information, so it
  61    --  needs not be read by tools like gnatbind, gnatmake etc.
  62
  63    --  -------------------
  64    --  -- Scope Section --
  65    --  -------------------
  66
  67    --  A first section defines the scopes in which entities are defined and
  68    --  referenced. A scope is a package/subprogram declaration/body. Note that
  69    --  a package declaration and body define two different scopes. Similarly, a
  70    --  subprogram declaration and body, when both present, define two different
  71    --  scopes.
  72
  73    --    FD dependency-number filename (-> unit-filename)?
  74
  75    --      This header precedes scope information for the unit identified by
  76    --      dependency number and file name. The dependency number is the index
  77    --      into the generated D lines and is ones-origin (e.g. 2 = reference to
  78    --      second generated D line).
  79
  80    --      The list of FD lines should match the list of D lines defined in the
  81    --      ALI file, in the same order.
  82
  83    --      Note that the filename here will reflect the original name if a
  84    --      Source_Reference pragma was encountered (since all line number
  85    --      references will be with respect to the original file).
  86
  87    --      Note: the filename is redundant in that it could be deduced from the
  88    --      corresponding D line, but it is convenient at least for human
  89    --      reading of the Alfa information, and means that the Alfa information
  90    --      can stand on its own without needing other parts of the ALI file.
  91
  92    --      The optional unit filename is given only for subunits.
  93
  94    --    FS . scope line type col entity (-> spec-file . spec-scope)?
  95
  96    --      (The ? mark stands for an optional entry in the syntax)
  97
  98    --      scope is the ones-origin scope number for the current file (e.g. 2 =
  99    --      reference to the second FS line in this FD block).
 100
 101    --      line is the line number of the scope entity. The name of the entity
 102    --      starts in column col. Columns are numbered from one, and if
 103    --      horizontal tab characters are present, the column number is computed
 104    --      assuming standard 1,9,17,.. tab stops. For example, if the entity is
 105    --      the first token on the line, and is preceded by space-HT-space, then
 106    --      the column would be column 10.
 107
 108    --      type is a single letter identifying the type of the entity, using
 109    --      the same code as in cross-references:
 110
 111    --        K = package
 112    --        V = function
 113    --        U = procedure
 114
 115    --      col is the column number of the scope entity
 116
 117    --      entity is the name of the scope entity, with casing in the canonical
 118    --      casing for the source file where it is defined.
 119
 120    --      spec-file and spec-scope are respectively the file and scope for the
 121    --      spec corresponding to the current body scope, when they differ.
 122
 123    --  ------------------
 124    --  -- Xref Section --
 125    --  ------------------
 126
 127    --  A second section defines cross-references useful for computing the set
 128    --  of global variables read/written in each subprogram/package.
 129
 130    --    FX dependency-number filename . entity-number entity
 131
 132    --      dependency-number and filename identity a file in FD lines
 133
 134    --      entity-number and identity identify a scope entity in FS lines for
 135    --      the file previously identified.
 136
 137    --    line typ col entity ref*
 138
 139    --      line is the line number of the referenced entity
 140
 141    --      typ is the type of the referenced entity, using a code similar to
 142    --      the one used for cross-references:
 143
 144    --        > = IN parameter
 145    --        < = OUT parameter
 146    --        = = IN OUT parameter
 147    --        * = all other cases
 148
 149    --      col is the column number of the referenced entity
 150
 151    --      entity is the name of the referenced entity as written in the source
 152    --      file where it is defined.
 153
 154    --  There may be zero or more ref entries on each line
 155
 156    --    (file |)? ((. scope :)? line type col)*
 157
 158    --      file is the dependency number of the file with the reference. It and
 159    --      the following vertical bar are omitted if the file is the same as
 160    --      the previous ref, and the refs for the current file are first (and
 161    --      do not need a bar).
 162
 163    --      scope is the scope number of the scope with the reference. It and
 164    --      the following colon are omitted if the scope is the same as the
 165    --      previous ref, and the refs for the current scope are first (and do
 166    --      not need a colon).
 167
 168    --      line is the line number of the reference
 169
 170    --      col is the column number of the reference
 171
 172    --      type is one of the following, using the same code as in
 173    --      cross-references:
 174
 175    --        m = modification
 176    --        r = reference
 177    --        s = subprogram reference in a static call
 178
 179    --  Special entries for reads and writes to memory reference a special
 180    --  variable called "__HEAP". These special entries are present in every
 181    --  scope where reads and writes to memory are present. Line and column for
 182    --  this special variable are always 0.
 183
 184    --    Examples: ??? add examples here
 185
 186    ----------------
 187    -- Xref Table --
 188    ----------------
 189
 190    --  The following table records Alfa cross-references
 191
 192    type Xref_Index is new Int;
 193    --  Used to index values in this table. Values start at 1 and are assigned
 194    --  sequentially as entries are constructed.
 195
 196    type Alfa_Xref_Record is record
 197       Entity_Name : String_Ptr;
 198       --  Pointer to entity name in ALI file
 199
 200       Entity_Line : Nat;
 201       --  Line number for the entity referenced
 202
 203       Etype : Character;
 204       --  Indicates type of entity, using code used in ALI file:
 205       --    > = IN parameter
 206       --    < = OUT parameter
 207       --    = = IN OUT parameter
 208       --    * = all other cases
 209
 210       Entity_Col : Nat;
 211       --  Column number for the entity referenced
 212
 213       File_Num : Nat;
 214       --  Set to the file dependency number for the cross-reference. Note
 215       --  that if no file entry is present explicitly, this is just a copy
 216       --  of the reference for the current cross-reference section.
 217
 218       Scope_Num : Nat;
 219       --  Set to the scope number for the cross-reference. Note that if no
 220       --  scope entry is present explicitly, this is just a copy of the
 221       --  reference for the current cross-reference section.
 222
 223       Line : Nat;
 224       --  Line number for the reference
 225
 226       Rtype : Character;
 227       --  Indicates type of reference, using code used in ALI file:
 228       --    r = reference
 229       --    m = modification
 230       --    s = call
 231
 232       Col : Nat;
 233       --  Column number for the reference
 234    end record;
 235
 236    package Alfa_Xref_Table is new GNAT.Table (
 237      Table_Component_Type => Alfa_Xref_Record,
 238      Table_Index_Type     => Xref_Index,
 239      Table_Low_Bound      => 1,
 240      Table_Initial        => 2000,
 241      Table_Increment      => 300);
 242
 243    -----------------
 244    -- Scope Table --
 245    -----------------
 246
 247    --  This table keeps track of the scopes and the corresponding starting and
 248    --  ending indexes (From, To) in the Xref table.
 249
 250    type Scope_Index is new Int;
 251    --  Used to index values in this table. Values start at 1 and are assigned
 252    --  sequentially as entries are constructed.
 253
 254    type Alfa_Scope_Record is record
 255       Scope_Name : String_Ptr;
 256       --  Pointer to scope name in ALI file
 257
 258       File_Num : Nat;
 259       --  Set to the file dependency number for the scope
 260
 261       Scope_Num : Nat;
 262       --  Set to the scope number for the scope
 263
 264       Spec_File_Num : Nat;
 265       --  Set to the file dependency number for the scope corresponding to the
 266       --  spec of the current scope entity, if different, or else 0.
 267
 268       Spec_Scope_Num : Nat;
 269       --  Set to the scope number for the scope corresponding to the spec of
 270       --  the current scope entity, if different, or else 0.
 271
 272       Line : Nat;
 273       --  Line number for the scope
 274
 275       Stype : Character;
 276       --  Indicates type of scope, using code used in ALI file:
 277       --    K = package
 278       --    V = function
 279       --    U = procedure
 280
 281       Col : Nat;
 282       --  Column number for the scope
 283
 284       From_Xref : Xref_Index;
 285       --  Starting index in Xref table for this scope
 286
 287       To_Xref : Xref_Index;
 288       --  Ending index in Xref table for this scope
 289
 290       --  The following component is only used in-memory, not printed out in
 291       --  ALI file.
 292
 293       Scope_Entity : Entity_Id := Empty;
 294       --  Entity (subprogram or package) for the scope
 295    end record;
 296
 297    package Alfa_Scope_Table is new GNAT.Table (
 298      Table_Component_Type => Alfa_Scope_Record,
 299      Table_Index_Type     => Scope_Index,
 300      Table_Low_Bound      => 1,
 301      Table_Initial        => 200,
 302      Table_Increment      => 300);
 303
 304    ----------------
 305    -- File Table --
 306    ----------------
 307
 308    --  This table keeps track of the units and the corresponding starting and
 309    --  ending indexes (From, To) in the Scope table.
 310
 311    type File_Index is new Int;
 312    --  Used to index values in this table. Values start at 1 and are assigned
 313    --  sequentially as entries are constructed.
 314
 315    type Alfa_File_Record is record
 316       File_Name : String_Ptr;
 317       --  Pointer to file name in ALI file
 318
 319       Unit_File_Name : String_Ptr;
 320       --  Pointer to file name for unit in ALI file, when File_Name refers to a
 321       --  subunit. Otherwise null.
 322
 323       File_Num : Nat;
 324       --  Dependency number in ALI file
 325
 326       From_Scope : Scope_Index;
 327       --  Starting index in Scope table for this unit
 328
 329       To_Scope : Scope_Index;
 330       --  Ending index in Scope table for this unit
 331    end record;
 332
 333    package Alfa_File_Table is new GNAT.Table (
 334      Table_Component_Type => Alfa_File_Record,
 335      Table_Index_Type     => File_Index,
 336      Table_Low_Bound      => 1,
 337      Table_Initial        => 20,
 338      Table_Increment      => 200);
 339
 340    ---------------
 341    -- Constants --
 342    ---------------
 343
 344    Name_Of_Heap_Variable : constant String := "__HEAP";
 345    --  Name of special variable used in effects to denote reads and writes
 346    --  through explicit dereference.
 347
 348    -----------------
 349    -- Subprograms --
 350    -----------------
 351
 352    procedure Initialize_Alfa_Tables;
 353    --  Reset tables for a new compilation
 354
 355    procedure dalfa;
 356    --  Debug routine to dump internal Alfa tables. This is a raw format dump
 357    --  showing exactly what the tables contain.
 358
 359    procedure palfa;
 360    --  Debugging procedure to output contents of Alfa binary tables in the
 361    --  format in which they appear in an ALI file.
 362
 363 end Alfa;