File : lib-writ.ads
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- L I B . W R I T --
6 -- --
7 -- S p e c --
8 -- --
9 -- Copyright (C) 1992-2015, 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 contains the routines for writing the library information
27
28 package Lib.Writ is
29
30 -----------------------------------
31 -- Format of Library Information --
32 -----------------------------------
33
34 -- This section describes the format of the library information that is
35 -- associated with object files. The exact method of this association is
36 -- potentially implementation dependent and is described and implemented in
37 -- package ali. From the point of view of the description here, all we need
38 -- to know is that the information is represented as a string of characters
39 -- that is somehow associated with an object file, and can be retrieved. If
40 -- no library information exists for a given object file, then we take this
41 -- as equivalent to the non-existence of the object file, as if source file
42 -- has not been previously compiled.
43
44 -- The library information is written as a series of lines of the form:
45
46 -- Key_Character parameter parameter ...
47
48 -- The following sections describe the format of these lines in detail
49
50 --------------------------------------
51 -- Making Changes to the ALI Format --
52 --------------------------------------
53
54 -- A number of tools use ali.adb to parse ali files. This means that
55 -- changes to this format can cause old versions of these tools to be
56 -- incompatible with new versions of the compiler. Any changes to ali file
57 -- formats must be carefully evaluated to understand any such possible
58 -- conflicts, and in particular, it is very undesirable to create conflicts
59 -- between older versions of GPS and newer versions of the compiler.
60
61 -- If the following guidelines are respected, downward compatibility
62 -- problems (old tools reading new ali files) should be minimized:
63
64 -- The basic key character format must be kept
65
66 -- The V line must be the first line, this is checked by ali.adb even in
67 -- Ignore_Errors mode, and is used to verify that the file at hand is
68 -- indeed likely intended to be an ali file.
69
70 -- The P line must be present, though may be modified in contents
71 -- according to remaining guidelines. Again, ali.adb assumes the P
72 -- line is present even in Ignore_Errors mode.
73
74 -- New modifiers can generally be added (in particular adding new two
75 -- letter modifiers to the P or U lines is always safe)
76
77 -- Adding entirely new lines (with a new key letter) to the ali file is
78 -- always safe, at any point (other than before the V line), since such
79 -- lines will be ignored.
80
81 -- Following the guidelines in this section should ensure that this problem
82 -- is minimized and that old tools will be able to deal successfully with
83 -- new ali formats. Note that this does not apply to the compiler itself,
84 -- which always requires consistency between the ali files and the binder.
85 -- That is because one of the main functions of the binder is to ensure
86 -- consistency of the partition, and this can be compromised if the ali
87 -- files are inconsistent.
88
89 ------------------
90 -- Header Lines --
91 ------------------
92
93 -- The initial header lines in the file give information about the
94 -- compilation environment, and identify other special information such as
95 -- main program parameters.
96
97 -- ----------------
98 -- -- V Version --
99 -- ----------------
100
101 -- V "xxxxxxxxxxxxxxxx"
102 --
103 -- This line indicates the library output version, as defined in
104 -- Gnatvsn. It ensures that separate object modules of a program are
105 -- consistent. It has to be changed if anything changes which would
106 -- affect successful binding of separately compiled modules. Examples
107 -- of such changes are modifications in the format of the library info
108 -- described in this package, or modifications to calling sequences, or
109 -- to the way that data is represented.
110
111 -- Note: the V line absolutely must be the first line, and no change
112 -- to the ALI format should change this, since even in Ignore_Errors
113 -- mode, Scan_ALI insists on finding a V line.
114
115 -- ---------------------
116 -- -- M Main Program --
117 -- ---------------------
118
119 -- M type [priority] [T=time-slice] [C=cpu] W=?
120
121 -- This line appears only if the main unit for this file is suitable
122 -- for use as a main program. The parameters are:
123
124 -- type
125
126 -- P for a parameterless procedure
127 -- F for a function returning a value of integral type
128 -- (used for writing a main program returning an exit status)
129
130 -- priority
131
132 -- Present only if there was a valid pragma Priority in the
133 -- corresponding unit to set the main task priority. It is an
134 -- unsigned decimal integer.
135
136 -- T=time-slice
137
138 -- Present only if there was a valid pragma Time_Slice in the
139 -- corresponding unit. It is an unsigned decimal integer in the
140 -- range 0 .. 10**9 giving the time slice value in units of
141 -- milliseconds. The actual significance of this parameter is
142 -- target dependent.
143
144 -- C=cpu
145
146 -- Present only if there was a valid pragma CPU in the
147 -- corresponding unit to set the main task affinity. It is an
148 -- unsigned decimal integer.
149
150 -- W=?
151
152 -- This parameter indicates the wide character encoding method used
153 -- when compiling the main program file. The ? character is the
154 -- single character used in the -gnatW? switch. This is used to
155 -- provide the default wide-character encoding for Wide_Text_IO
156 -- files.
157
158 -- -----------------
159 -- -- A Argument --
160 -- -----------------
161
162 -- A argument
163
164 -- One of these lines appears for each of the arguments present in the
165 -- call to the gnat1 program. This can be used if it is necessary to
166 -- reconstruct this call (e.g. for fix and continue).
167
168 -- -------------------
169 -- -- P Parameters --
170 -- -------------------
171
172 -- P <<parameters>>
173
174 -- Indicates various information that applies to the compilation of the
175 -- corresponding source file. Parameters is a sequence of zero or more
176 -- two letter codes that indicate configuration pragmas and other
177 -- parameters that apply:
178
179 -- The arguments are as follows:
180
181 -- CE Compilation errors. If this is present it means that the ali
182 -- file resulted from a compilation with the -gnatQ switch set,
183 -- and illegalities were detected. The ali file contents may
184 -- not be completely reliable, but the format will be correct
185 -- and complete. Note that NO is always present if CE is
186 -- present.
187
188 -- DB Detect_Blocking pragma is in effect for all units in this
189 -- file.
190
191 -- Ex A valid Partition_Elaboration_Policy pragma applies to all
192 -- the units in this file, where x is the first character
193 -- (upper case) of the policy name (e.g. 'C' for Concurrent).
194
195 -- FX Units in this file use front-end exceptions, with explicit
196 -- handlers to trigger AT-END actions on exception paths.
197
198 -- GP Set if this compilation was done in GNATprove mode, either
199 -- from direct use of GNATprove, or from use of -gnatdF.
200
201 -- Lx A valid Locking_Policy pragma applies to all the units in
202 -- this file, where x is the first character (upper case) of
203 -- the policy name (e.g. 'C' for Ceiling_Locking).
204
205 -- NO No object. This flag indicates that the units in this file
206 -- were not compiled to produce an object. This can occur as a
207 -- result of the use of -gnatc, or if no object can be produced
208 -- (e.g. when a package spec is compiled instead of the body,
209 -- or a subunit on its own). Note that in GNATprove mode, we
210 -- do produce an object. The object is not suitable for binding
211 -- and linking, but we do not set NO, instead we set GP.
212
213 -- NR No_Run_Time. Indicates that a pragma No_Run_Time applies
214 -- to all units in the file.
215
216 -- NS Normalize_Scalars pragma in effect for all units in
217 -- this file.
218
219 -- OH Pragma Default_Scalar_Storage_Order (High_Order_First) is
220 -- present in a configuration pragma file that applies.
221
222 -- OL Pragma Default_Scalar_Storage_Order (Low_Order_First) is
223 -- present in a configuration pragma file that applies.
224
225 -- Qx A valid Queueing_Policy pragma applies to all the units
226 -- in this file, where x is the first character (upper case)
227 -- of the policy name (e.g. 'P' for Priority_Queueing).
228
229 -- SL Indicates that the unit is an Interface to a Standalone
230 -- Library. Note that this indication is never given by the
231 -- compiler, but is added by the Project Manager in gnatmake
232 -- when an Interface ALI file is copied to the library
233 -- directory.
234
235 -- SS This unit references System.Secondary_Stack (that is,
236 -- the unit makes use of the secondary stack facilities).
237
238 -- Tx A valid Task_Dispatching_Policy pragma applies to all
239 -- the units in this file, where x is the first character
240 -- (upper case) of the corresponding policy name (e.g. 'F'
241 -- for FIFO_Within_Priorities).
242
243 -- UA Unreserve_All_Interrupts pragma was processed in one or
244 -- more units in this file
245
246 -- ZX Units in this file use zero-cost exceptions and have
247 -- generated exception tables. If ZX is not present, the
248 -- longjmp/setjmp exception scheme is in use.
249
250 -- Note that language defined units never output policy (Lx, Tx, Qx)
251 -- parameters. Language defined units must correctly handle all
252 -- possible cases. These values are checked for consistency by the
253 -- binder and then copied to the generated binder output file.
254
255 -- Note: The P line must be present. Even in Ignore_Errors mode, Scan_ALI
256 -- insists on finding a P line. So if changes are made to the ALI format,
257 -- they should not include removing the P line.
258
259 -- ---------------------
260 -- -- R Restrictions --
261 -- ---------------------
262
263 -- There are two forms for R lines, positional and named. The positional
264 -- notation is now considered obsolescent, it is not generated by the most
265 -- recent versions of the compiler except under control of the debug switch
266 -- -gnatdR, but is still recognized by the binder.
267
268 -- The recognition by the binder is to ease the transition, and better deal
269 -- with some cases of inconsistent builds using incompatible versions of
270 -- the compiler and binder. The named notation is the current preferred
271 -- approach.
272
273 -- Note that R lines are generated using the information in unit Rident,
274 -- and intepreted by the binder using the information in System.Rident.
275 -- Normally these two units should be effectively identical. However in
276 -- some cases of inconsistent builds, they may be different. This may lead
277 -- to binder diagnostics, which can be suppressed using the -C switch for
278 -- the binder, which results in ignoring unrecognized restrictions in the
279 -- ali files.
280
281 -- ---------------------------------------
282 -- -- R Restrictions (Positional Form) --
283 -- ---------------------------------------
284
285 -- The first R line records the status of restrictions generated by pragma
286 -- Restrictions encountered, as well as information on what the compiler
287 -- has been able to determine with respect to restrictions violations.
288 -- The format is:
289
290 -- R <<restriction-characters>> <<restriction-param-id-entries>>
291
292 -- The first parameter is a string of characters that records
293 -- information regarding restrictions that do not take parameter not
294 -- take parameter values. It is a string of characters, one character
295 -- for each value (in order) in All_Boolean_Restrictions. There are
296 -- three possible settings for each restriction:
297
298 -- r Restricted. Unit was compiled under control of a pragma
299 -- Restrictions for the corresponding restriction. In this case
300 -- the unit certainly does not violate the Restriction, since
301 -- this would have been detected by the compiler.
302
303 -- n Not used. The unit was not compiled under control of a pragma
304 -- Restrictions for the corresponding restriction, and does not
305 -- make any use of the referenced feature.
306
307 -- v Violated. The unit was not compiled under control of a pragma
308 -- Restrictions for the corresponding restriction, and it does
309 -- indeed use the referenced feature.
310
311 -- This information is used in the binder to check consistency, i.e. to
312 -- detect cases where one unit has "r" and another unit has "v", which
313 -- is not permitted, since these restrictions are partition-wide.
314
315 -- The second parameter, which immediately follows the first (with no
316 -- separating space) gives restriction information for identifiers for
317 -- which a parameter is given.
318
319 -- The parameter is a string of entries, one for each value in
320 -- Restrict.All_Parameter_Restrictions. Each entry has two components
321 -- in sequence, the first indicating whether or not there is a
322 -- restriction, and the second indicating whether or not the compiler
323 -- detected violations. In the boolean case it is not necessary to
324 -- separate these, since if a restriction is set, and violated, that is
325 -- an error. But in the parameter case, this is not true. For example,
326 -- we can have a unit with a pragma Restrictions (Max_Tasks => 4),
327 -- where the compiler can detect that there are exactly three tasks
328 -- declared. Both of these pieces of information must be passed to the
329 -- binder. The parameter of 4 is important in case the total number of
330 -- tasks in the partition is greater than 4. The parameter of 3 is
331 -- important in case some other unit has a restrictions pragma with
332 -- Max_Tasks=>2.
333
334 -- The component for the presence of restriction has one of two
335 -- possible forms:
336
337 -- n No pragma for this restriction is present in the set of units
338 -- for this ali file.
339
340 -- rN At least one pragma for this restriction is present in the
341 -- set of units for this ali file. The value N is the minimum
342 -- parameter value encountered in any such pragma. N is in the
343 -- range of Integer (a value larger than N'Last causes the
344 -- pragma to be ignored).
345
346 -- The component for the violation detection has one of three
347 -- possible forms:
348
349 -- n No violations were detected by the compiler
350
351 -- vN A violation was detected. N is either the maximum or total
352 -- count of violations (depending on the checking type) in all
353 -- the units represented by the ali file). Note that this
354 -- setting is only allowed for restrictions that are in
355 -- Checked_[Max|Sum]_Parameter_Restrictions. The value here is
356 -- known to be exact by the compiler and is in the range of
357 -- Natural.
358
359 -- vN+ A violation was detected. The compiler cannot determine
360 -- the exact count of violations, but it is at least N.
361
362 -- There are no spaces within the parameter string, so the entry
363 -- described above in the header of this section for Max_Tasks would
364 -- appear as the string r4v3.
365
366 -- Note: The restrictions line is required to be present. Even in
367 -- Ignore_Errors mode, Scan_ALI expects to find an R line and will
368 -- signal a fatal error if it is missing. This means that future
369 -- changes to the ALI file format must retain the R line.
370
371 -- ----------------------------------
372 -- -- R Restrictions (Named Form) --
373 -- ----------------------------------
374
375 -- The first R line for named form announces that named notation will be
376 -- used, and also assures that there is at least one R line present, which
377 -- makes parsing of ali files simpler. A blank line preceds the RN line.
378
379 -- RN
380
381 -- In named notation, the restrictions are given as a series of lines,
382 -- one per restrictions that is specified or violated (no information is
383 -- present for restrictions that are not specified or violated). In the
384 -- following name is the name of the restriction in all upper case.
385
386 -- For boolean restrictions, we have only two possibilities. A restrictions
387 -- pragma is present, or a violation is detected:
388
389 -- RR name
390
391 -- A restriction pragma is present for the named boolean restriction.
392 -- No violations were detected by the compiler (or the unit in question
393 -- would have been found to be illegal).
394
395 -- RV name
396
397 -- No restriction pragma is present for the named boolean restriction.
398 -- However, the compiler did detect one or more violations of this
399 -- restriction, which may require a binder consistency check. Note that
400 -- one case of a violation is the use of a Restriction_Set attribute for
401 -- the restriction that yielded False.
402
403 -- For the case of restrictions that take a parameter, we need both the
404 -- information from pragma if present, and the actual information about
405 -- what possible violations occur. For example, we can have a unit with
406 -- a pragma Restrictions (Max_Tasks => 4), where the compiler can detect
407 -- that there are exactly three tasks declared. Both of these pieces
408 -- of information must be passed to the binder. The parameter of 4 is
409 -- important in case the total number of tasks in the partition is greater
410 -- than 4. The parameter of 3 is important in case some other unit has a
411 -- restrictions pragma with Max_Tasks=>2.
412
413 -- RR name=N
414
415 -- A restriction pragma is present for the named restriction which is
416 -- one of the restrictions taking a parameter. The value N (a decimal
417 -- integer) is the value given in the restriction pragma.
418
419 -- RV name=N
420
421 -- A restriction pragma may or may not be present for the restriction
422 -- given by name (one of the restrictions taking a parameter). But in
423 -- either case, the compiler detected possible violations. N (a decimal
424 -- integer) is the maximum or total count of violations (depending
425 -- on the checking type) in all the units represented by the ali file).
426 -- The value here is known to be exact by the compiler and is in the
427 -- range of Natural. Note that if an RR line is present for the same
428 -- restriction, then the value in the RV line cannot exceed the value
429 -- in the RR line (since otherwise the compiler would have detected a
430 -- violation of the restriction).
431
432 -- RV name=N+
433
434 -- Similar to the above, but the compiler cannot determine the exact
435 -- count of violations, but it is at least N.
436
437 -- -------------------------------------------------
438 -- -- R Restrictions (No_Dependence Information) --
439 -- -------------------------------------------------
440
441 -- Subsequent R lines are present only if pragma Restriction No_Dependence
442 -- is used. There is one such line for each such pragma appearing in the
443 -- extended main unit. The format is:
444
445 -- R unit_name
446
447 -- Here the unit name is in all lower case. The components of the unit
448 -- name are separated by periods. The names themselves are in encoded
449 -- form, as documented in Namet.
450
451 -- -------------------------
452 -- -- I Interrupt States --
453 -- -------------------------
454
455 -- I interrupt-number interrupt-state line-number
456
457 -- This line records information from an Interrupt_State pragma. There
458 -- is one line for each separate pragma, and if no such pragmas are
459 -- used, then no I lines are present.
460
461 -- The interrupt-number is an unsigned positive integer giving the
462 -- value of the interrupt as defined in Ada.Interrupts.Names.
463
464 -- The interrupt-state is one of r/s/u for Runtime/System/User
465
466 -- The line number is an unsigned decimal integer giving the line
467 -- number of the corresponding Interrupt_State pragma. This is used
468 -- in consistency messages.
469
470 -- --------------------------------------
471 -- -- S Priority Specific Dispatching --
472 -- --------------------------------------
473
474 -- S policy_identifier first_priority last_priority line-number
475
476 -- This line records information from a Priority_Specific_Dispatching
477 -- pragma. There is one line for each separate pragma, and if no such
478 -- pragmas are used, then no S lines are present.
479
480 -- The policy_identifier is the first character (upper case) of the
481 -- corresponding policy name (e.g. 'F' for FIFO_Within_Priorities).
482
483 -- The first_priority and last_priority fields define the range of
484 -- priorities to which the specified dispatching policy apply.
485
486 -- The line number is an unsigned decimal integer giving the line
487 -- number of the corresponding Priority_Specific_Dispatching pragma.
488 -- This is used in consistency messages.
489
490 ----------------------------
491 -- Compilation Unit Lines --
492 ----------------------------
493
494 -- Following these header lines, a set of information lines appears for
495 -- each compilation unit that appears in the corresponding object file. In
496 -- particular, when a package body or subprogram body is compiled, there
497 -- will be two sets of information, one for the spec and one for the body,
498 -- with the entry for the body appearing first. This is the only case in
499 -- which a single ALI file contains more than one unit (in particular note
500 -- that subunits do *not* count as compilation units for this purpose, and
501 -- generate no library information, since they are inlined).
502
503 -- --------------------
504 -- -- U Unit Header --
505 -- --------------------
506
507 -- The lines for each compilation unit have the following form
508
509 -- U unit-name source-name version <<attributes>>
510
511 -- This line identifies the unit to which this section of the library
512 -- information file applies. The first three parameters are the unit
513 -- name in internal format, as described in package Uname, and the name
514 -- of the source file containing the unit.
515
516 -- Version is the version given as eight hexadecimal characters with
517 -- upper case letters. This value is the exclusive or of the source
518 -- checksums of the unit and all its semantically dependent units.
519
520 -- The <<attributes>> are a series of two letter codes indicating
521 -- information about the unit:
522
523 -- BD Unit does not have pragma Elaborate_Body, but the elaboration
524 -- circuit has determined that it would be a good idea if this
525 -- pragma were present, since the body of the package contains
526 -- elaboration code that modifies one or more variables in the
527 -- visible part of the package. The binder will try, but does
528 -- not promise, to keep the elaboration of the body close to
529 -- the elaboration of the spec.
530
531 -- DE Dynamic Elaboration. This unit was compiled with the dynamic
532 -- elaboration model, as set by either the -gnatE switch or
533 -- pragma Elaboration_Checks (Dynamic).
534 --
535 -- EB Unit has pragma Elaborate_Body, or is a generic instance that
536 -- has a body. Set for instances because RM 12.3(20) requires
537 -- that the body be immediately elaborated after the spec (we
538 -- would normally do that anyway, because elaborate spec and
539 -- body together whenever possible, and for an instance it is
540 -- always possible; however setting EB ensures that this is done
541 -- even when using the -p gnatbind switch).
542
543 -- EE Elaboration entity is present which must be set true when
544 -- the unit is elaborated. The name of the elaboration entity is
545 -- formed from the unit name in the usual way. If EE is present,
546 -- then this boolean must be set True as part of the elaboration
547 -- processing routine generated by the binder. Note that EE can
548 -- be set even if NE is set. This happens when the boolean is
549 -- needed solely for checking for the case of access before
550 -- elaboration.
551
552 -- GE Unit is a generic declaration, or corresponding body
553 --
554 -- IL Unit source uses a style with identifiers in all lower-case
555 -- IU (IL) or all upper case (IU). If the standard mixed-case usage
556 -- is detected, or the compiler cannot determine the style, then
557 -- no I parameter will appear.
558
559 -- IS Initialize_Scalars pragma applies to this unit, or else there
560 -- is at least one use of the Invalid_Value attribute.
561
562 -- KM Unit source uses a style with keywords in mixed case (KM)
563 -- KU or all upper case (KU). If the standard lower-case usage is
564 -- is detected, or the compiler cannot determine the style, then
565 -- no K parameter will appear.
566
567 -- NE Unit has no elaboration routine. All subprogram bodies and
568 -- specs are in this category. Package bodies and specs may or
569 -- may not have NE set, depending on whether or not elaboration
570 -- code is required. Set if N_Compilation_Unit node has flag
571 -- Has_No_Elaboration_Code set.
572
573 -- OL The units in this file are compiled with a local pragma
574 -- Optimize_Alignment, so no consistency requirement applies
575 -- to these units. All internal units have this status since
576 -- they have an automatic default of Optimize_Alignment (Off).
577 --
578 -- OO Optimize_Alignment (Off) is the default setting for all
579 -- units in this file. All files in the partition that specify
580 -- a default must specify the same default.
581
582 -- OS Optimize_Alignment (Space) is the default setting for all
583 -- units in this file. All files in the partition that specify
584 -- a default must specify the same default.
585
586 -- OT Optimize_Alignment (Time) is the default setting for all
587 -- units in this file. All files in the partition that specify
588 -- a default must specify the same default.
589
590 -- PF The unit has a library-level (package) finalizer
591
592 -- PK Unit is package, rather than a subprogram
593
594 -- PU Unit has pragma Pure
595
596 -- PR Unit has pragma Preelaborate
597
598 -- RA Unit declares a Remote Access to Class-Wide (RACW) type
599
600 -- RC Unit has pragma Remote_Call_Interface
601
602 -- RT Unit has pragma Remote_Types
603
604 -- SE Compilation of unit encountered one or more serious errors.
605 -- Normally the generation of an ALI file is suppressed if there
606 -- is a serious error, but this can be overridden with -gnatQ.
607
608 -- SP Unit has pragma Shared_Passive
609
610 -- SU Unit is a subprogram, rather than a package
611
612 -- The attributes may appear in any order, separated by spaces
613
614 -- -----------------------------
615 -- -- W, Y and Z Withed Units --
616 -- -----------------------------
617
618 -- Following each U line, is a series of lines of the form
619
620 -- W unit-name [source-name lib-name] [E] [EA] [ED] [AD]
621 -- or
622 -- Y unit-name [source-name lib-name] [E] [EA] [ED] [AD]
623 -- or
624 -- Z unit-name [source-name lib-name] [E] [EA] [ED] [AD]
625
626 -- One W line is present for each unit that is mentioned in an explicit
627 -- non-limited with clause by the current unit. One Y line is present
628 -- for each unit that is mentioned in an explicit limited with clause
629 -- by the current unit. One Z line is present for each unit that is
630 -- only implicitly withed by the current unit. The first parameter is
631 -- the unit name in internal format. The second parameter is the file
632 -- name of the file that must be compiled to compile this unit. It is
633 -- usually the file for the body, except for packages which have no
634 -- body. For units that need a body, if the source file for the body
635 -- cannot be found, the file name of the spec is used instead. The
636 -- third parameter is the file name of the library information file
637 -- that contains the results of compiling this unit. The optional
638 -- modifiers are used as follows:
639
640 -- E pragma Elaborate applies to this unit
641
642 -- EA pragma Elaborate_All applies to this unit
643
644 -- ED Elaborate_Desirable set for this unit, which means that there
645 -- is no Elaborate, but the analysis suggests that Program_Error
646 -- may be raised if the Elaborate conditions cannot be satisfied.
647 -- The binder will attempt to treat ED as E if it can.
648
649 -- AD Elaborate_All_Desirable set for this unit, which means that
650 -- there is no Elaborate_All, but the analysis suggests that
651 -- Program_Error may be raised if the Elaborate_All conditions
652 -- cannot be satisfied. The binder will attempt to treat AD as
653 -- EA if it can.
654
655 -- The parameter source-name and lib-name are omitted for the case of a
656 -- generic unit compiled with earlier versions of GNAT which did not
657 -- generate object or ali files for generics. For compatibility in the
658 -- bootstrap path we continue to omit these entries for predefined
659 -- generic units, even though we do now generate object and ali files.
660
661 -- However, in SPARK mode, we always generate source-name and lib-name
662 -- parameters. Bootstrap issues do not apply there, and we need this
663 -- information to properly compute frame conditions of subprograms.
664
665 -- The parameter source-name and lib-name are also omitted for the W
666 -- lines that result from use of a Restriction_Set attribute which gets
667 -- a result of False from a No_Dependence check, in the case where the
668 -- unit is not in the semantic closure. In such a case, the bare W
669 -- line is generated, but no D (dependency) line. This will make the
670 -- binder do the consistency check, but not include the unit in the
671 -- partition closure (unless it is properly With'ed somewhere).
672
673 -- -----------------------
674 -- -- L Linker_Options --
675 -- -----------------------
676
677 -- Following the W lines (if any, or the U line if not), are an optional
678 -- series of lines that indicates the usage of the pragma Linker_Options in
679 -- the associated unit. For each appearance of a pragma Linker_Options (or
680 -- Link_With) in the unit, a line is present with the form:
681
682 -- L "string"
683
684 -- where string is the string from the unit line enclosed in quotes.
685 -- Within the quotes the following can occur:
686
687 -- c graphic characters in range 20-7E other than " or {
688 -- "" indicating a single " character
689 -- {hh} indicating a character whose code is hex hh (0-9,A-F)
690 -- {00} [ASCII.NUL] is used as a separator character
691 -- to separate multiple arguments of a single
692 -- Linker_Options pragma.
693
694 -- For further details, see Stringt.Write_String_Table_Entry. Note that
695 -- wide characters in the form {hhhh} cannot be produced, since pragma
696 -- Linker_Option accepts only String, not Wide_String.
697
698 -- The L lines are required to appear in the same order as the
699 -- corresponding Linker_Options (or Link_With) pragmas appear in the
700 -- source file, so that this order is preserved by the binder in
701 -- constructing the set of linker arguments.
702
703 -- Note: Linker_Options lines never appear in the ALI file generated for
704 -- a predefined generic unit, and there is cicuitry in Sem_Prag to enforce
705 -- this restriction, which is needed because of not generating source name
706 -- and lib name parameters on the with lines for such files, as explained
707 -- above in the section on with lines.
708
709 -- --------------
710 -- -- N Notes --
711 -- --------------
712
713 -- The final section of unit-specific lines contains notes which record
714 -- annotations inserted in source code for processing by external tools
715 -- using pragmas. For each occurrence of any of these pragmas, a line is
716 -- generated with the following syntax:
717
718 -- N x<sloc> [<arg_id>:]<arg> ...
719
720 -- x is one of:
721 -- A pragma Annotate
722 -- C pragma Comment
723 -- I pragma Ident
724 -- T pragma Title
725 -- S pragma Subtitle
726
727 -- <sloc> is the source location of the pragma in line:col[:filename]
728 -- format. The file name is omitted if it is the same as the current
729 -- unit (it therefore appears explicitly in the case of pragmas
730 -- occurring in subunits, which do not have U sections of their own).
731
732 -- Successive entries record the pragma_argument_associations.
733
734 -- If a pragma argument identifier is present, the entry is prefixed
735 -- with the pragma argument identifier <arg_id> followed by a colon.
736
737 -- <arg> represents the pragma argument, and has the following
738 -- conventions:
739
740 -- - identifiers are output verbatim
741 -- - static string expressions are output as literals encoded as
742 -- for L lines
743 -- - static integer expressions are output as decimal literals
744 -- - any other expression is replaced by the placeholder "<expr>"
745
746 ---------------------
747 -- Reference Lines --
748 ---------------------
749
750 -- The reference lines contain information about references from any of the
751 -- units in the compilation (including body version and version attributes,
752 -- linker options pragmas and source dependencies).
753
754 -- ------------------------------------
755 -- -- E External Version References --
756 -- ------------------------------------
757
758 -- One of these lines is present for each use of 'Body_Version or 'Version
759 -- in any of the units of the compilation. These are used by the linker to
760 -- determine which version symbols must be output. The format is simply:
761
762 -- E name
763
764 -- where name is the external name, i.e. the unit name with either a S or a
765 -- B for spec or body version referenced (Body_Version always references
766 -- the body, Version references the Spec, except in the case of a reference
767 -- to a subprogram with no separate spec). Upper half and wide character
768 -- codes are encoded using the same method as in Namet (Uhh for upper half,
769 -- Whhhh for wide character, where hh are hex digits).
770
771 -- ---------------------
772 -- -- D Dependencies --
773 -- ---------------------
774
775 -- The dependency lines indicate the source files on which the compiled
776 -- units depend. This is used by the binder for consistency checking.
777 -- These lines are also referenced by the cross-reference information.
778
779 -- D source-name time-stamp checksum (sub)unit-name line:file-name
780
781 -- source-name also includes preprocessing data file and preprocessing
782 -- definition file. These preprocessing files may be given as full
783 -- path names instead of simple file names. If a full path name
784 -- includes a directory with spaces, the path name is quoted (quote
785 -- characters (") added at start and end, and any internal quotes are
786 -- doubled).
787
788 -- The time-stamp field contains the time stamp of the corresponding
789 -- source file. See types.ads for details on time stamp representation.
790
791 -- The checksum is an 8-hex digit representation of the source file
792 -- checksum, with letters given in lower case.
793
794 -- If the unit is not a subunit, the (sub)unit name is the unit name in
795 -- internal format, as described in package Uname. If the unit is a
796 -- subunit, the (sub)unit name is the fully qualified name of the
797 -- subunit in all lower case letters.
798
799 -- The line:file-name entry is present only if a Source_Reference
800 -- pragma appeared in the source file identified by source-name. In
801 -- this case, it gives the information from this pragma. Note that this
802 -- allows cross-reference information to be related back to the
803 -- original file. Note: the reason the line number comes first is that
804 -- a leading digit immediately identifies this as a Source_Reference
805 -- entry, rather than a subunit-name.
806
807 -- A line number of zero for line: in this entry indicates that there
808 -- is more than one source reference pragma. In this case, the line
809 -- numbers in the cross-reference are correct, and refer to the
810 -- original line number, but there is no information that allows a
811 -- reader of the ALI file to determine the exact mapping of physical
812 -- line numbers back to the original source.
813
814 -- Files with a zero checksum and a non-zero time stamp are in general
815 -- files on which the compilation depends but which are not Ada files
816 -- with further dependencies. This includes preprocessor data files
817 -- and preprocessor definition files.
818
819 -- Note: blank lines are ignored when the library information is read,
820 -- and separate sections of the file are separated by blank lines to
821 -- ease readability. Blanks between fields are also ignored.
822
823 -- For entries corresponding to files that were not present (and thus
824 -- resulted in error messages), or for files that are not part of the
825 -- dependency set, both the time stamp and checksum are set to all zero
826 -- characters. These dummy entries are ignored by the binder in
827 -- dependency checking, but must be present for proper interpretation
828 -- of the cross-reference data.
829
830 --------------------------
831 -- Cross-Reference Data --
832 --------------------------
833
834 -- The cross-reference data follows the dependency lines. See the spec of
835 -- Lib.Xref in file lib-xref.ads for details on the format of this data.
836
837 ---------------------------------
838 -- Source Coverage Obligations --
839 ---------------------------------
840
841 -- The Source Coverage Obligation (SCO) information follows the cross-
842 -- reference data. See the spec of Par_SCO in file par_sco.ads for full
843 -- details of the format.
844
845 ---------------------------------------
846 -- SPARK Cross-Reference Information --
847 ---------------------------------------
848
849 -- The SPARK cross-reference information follows the SCO information. See
850 -- the spec of SPARK_Xrefs in file spark_xrefs.ads for full details of the
851 -- format.
852
853 -------------------------------
854 -- ALI File Generation for C --
855 -------------------------------
856
857 -- The C compiler can also generate ALI files for use by the IDE's in
858 -- providing navigation services in C. These ALI files are a subset of
859 -- the specification above, lacking all Ada-specific output. Primarily
860 -- the IDE uses the cross-reference sections of such files.
861
862 ----------------------
863 -- Global Variables --
864 ----------------------
865
866 -- The table defined here stores one entry for each Interrupt_State pragma
867 -- encountered either in the main source or in an ancillary with'ed source.
868 -- Since interrupt state values have to be consistent across all units in a
869 -- partition, we detect inconsistencies at compile time when we can.
870
871 type Interrupt_State_Entry is record
872 Interrupt_Number : Pos;
873 -- Interrupt number value
874
875 Interrupt_State : Character;
876 -- Set to r/s/u for Runtime/System/User
877
878 Pragma_Loc : Source_Ptr;
879 -- Location of pragma setting this value in place
880 end record;
881
882 package Interrupt_States is new Table.Table (
883 Table_Component_Type => Interrupt_State_Entry,
884 Table_Index_Type => Nat,
885 Table_Low_Bound => 1,
886 Table_Initial => 30,
887 Table_Increment => 200,
888 Table_Name => "Name_Interrupt_States");
889
890 -- The table structure defined here stores one entry for each
891 -- Priority_Specific_Dispatching pragma encountered either in the main
892 -- source or in an ancillary with'ed source. Since have to be consistent
893 -- across all units in a partition, we may as well detect inconsistencies
894 -- at compile time when we can.
895
896 type Specific_Dispatching_Entry is record
897 Dispatching_Policy : Character;
898 -- First character (upper case) of the corresponding policy name
899
900 First_Priority : Nat;
901 -- Lower bound of the priority range to which the specified dispatching
902 -- policy applies.
903
904 Last_Priority : Nat;
905 -- Upper bound of the priority range to which the specified dispatching
906 -- policy applies.
907
908 Pragma_Loc : Source_Ptr;
909 -- Location of pragma setting this value in place
910 end record;
911
912 package Specific_Dispatching is new Table.Table (
913 Table_Component_Type => Specific_Dispatching_Entry,
914 Table_Index_Type => Nat,
915 Table_Low_Bound => 1,
916 Table_Initial => 10,
917 Table_Increment => 100,
918 Table_Name => "Name_Priority_Specific_Dispatching");
919
920 -----------------
921 -- Subprograms --
922 -----------------
923
924 procedure Ensure_System_Dependency;
925 -- This procedure ensures that a dependency is created on system.ads. Even
926 -- if there is no semantic dependency, Targparm has read the file to
927 -- acquire target parameters, so we need a source dependency.
928
929 procedure Write_ALI (Object : Boolean);
930 -- This procedure writes the library information for the current main unit
931 -- The Object parameter is true if an object file is created, and false
932 -- otherwise. Note that the pseudo-object file generated in GNATProve mode
933 -- does count as an object file from this point of view.
934 --
935 -- Note: in the case where we are not generating code (-gnatc mode), this
936 -- routine only writes an ALI file if it cannot find an existing up to
937 -- date ALI file. If it *can* find an existing up to date ALI file, then
938 -- it reads this file and sets the Lib.Compilation_Arguments table from
939 -- the A lines in this file.
940
941 procedure Add_Preprocessing_Dependency (S : Source_File_Index);
942 -- Indicate that there is a dependency to be added on a preprocessing data
943 -- file or on a preprocessing definition file.
944
945 end Lib.Writ;