1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                                D E B U G                                 --
6--                                                                          --
7--                                 B o d y                                  --
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.                                     --
17--                                                                          --
18-- As a special exception under Section 7 of GPL version 3, you are granted --
19-- additional permissions described in the GCC Runtime Library Exception,   --
20-- version 3.1, as published by the Free Software Foundation.               --
21--                                                                          --
22-- You should have received a copy of the GNU General Public License and    --
23-- a copy of the GCC Runtime Library Exception along with this program;     --
24-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
25-- <http://www.gnu.org/licenses/>.                                          --
26--                                                                          --
27-- GNAT was originally developed  by the GNAT team at  New York University. --
28-- Extensive contributions were provided by Ada Core Technologies Inc.      --
29--                                                                          --
30------------------------------------------------------------------------------
31
32package body Debug is
33
34   ---------------------------------
35   -- Summary of Debug Flag Usage --
36   ---------------------------------
37
38   --  Debug flags for compiler (GNAT1)
39
40   --  da   Generate messages tracking semantic analyzer progress
41   --  db   Show encoding of type names for debug output
42   --  dc   List names of units as they are compiled
43   --  dd   Dynamic allocation of tables messages generated
44   --  de   List the entity table
45   --  df   Full tree/source print (includes withed units)
46   --  dg   Print source from tree (generated code only)
47   --  dh   Generate listing showing loading of name table hash chains
48   --  di   Generate messages for visibility linking/delinking
49   --  dj   Suppress "junk null check" for access parameter values
50   --  dk   Generate GNATBUG message on abort, even if previous errors
51   --  dl   Generate unit load trace messages
52   --  dm
53   --  dn   Generate messages for node/list allocation
54   --  do   Print source from tree (original code only)
55   --  dp   Generate messages for parser scope stack push/pops
56   --  dq   No auto-alignment of small records
57   --  dr   Generate parser resynchronization messages
58   --  ds   Print source from tree (including original and generated stuff)
59   --  dt   Print full tree
60   --  du   Uncheck categorization pragmas
61   --  dv   Output trace of overload resolution
62   --  dw   Print trace of semantic scope stack
63   --  dx   Force expansion on, even if no code being generated
64   --  dy   Print tree of package Standard
65   --  dz   Print source of package Standard
66
67   --  dA   All entities included in representation information output
68   --  dB   Output debug encoding of type names and variants
69   --  dC   Output debugging information on check suppression
70   --  dD   Delete elaboration checks in inner level routines
71   --  dE   Apply elaboration checks to predefined units
72   --  dF   Front end data layout enabled
73   --  dG   Generate all warnings including those normally suppressed
74   --  dH   Hold (kill) call to gigi
75   --  dI   Inhibit internal name numbering in gnatG listing
76   --  dJ   Output debugging trace info for JGNAT (Java VM version of GNAT)
77   --  dK   Kill all error messages
78   --  dL   Output trace information on elaboration checking
79   --  dM   Assume all variables are modified (no current values)
80   --  dN   No file name information in exception messages
81   --  dO   Output immediate error messages
82   --  dP   Do not check for controlled objects in preelaborable packages
83   --  dQ
84   --  dR   Bypass check for correct version of s-rpc
85   --  dS   Never convert numbers to machine numbers in Sem_Eval
86   --  dT   Convert to machine numbers only for constant declarations
87   --  dU   Enable garbage collection of unreachable entities
88   --  dV   Enable viewing of all symbols in debugger
89   --  dW   Disable warnings on calls for IN OUT parameters
90   --  dX   Display messages on reads of potentially uninitialized scalars
91   --  dY   Enable configurable run-time mode
92   --  dZ   Generate listing showing the contents of the dispatch tables
93
94   --  d.a  Force Target_Strict_Alignment mode to True
95   --  d.b  Dump backend types
96   --  d.c  Generate inline concatenation, do not call procedure
97   --  d.d  Disable atomic synchronization
98   --  d.e  Enable atomic synchronization
99   --  d.f  Inhibit folding of static expressions
100   --  d.g  Enable conversion of raise into goto
101   --  d.h  Minimize the creation of public internal symbols for concatenation
102   --  d.i  Ignore Warnings pragmas
103   --  d.j  Generate listing of frontend inlined calls
104   --  d.k
105   --  d.l  Use Ada 95 semantics for limited function returns
106   --  d.m  For -gnatl, print full source only for main unit
107   --  d.n  Print source file names
108   --  d.o  Generate .NET listing of CIL code
109   --  d.p  Enable the .NET CIL verifier
110   --  d.q
111   --  d.r  Enable OK_To_Reorder_Components in non-variant records
112   --  d.s  Disable expansion of slice move, use memmove
113   --  d.t  Disable static allocation of library level dispatch tables
114   --  d.u  Enable Modify_Tree_For_C (update tree for c)
115   --  d.v  Enable OK_To_Reorder_Components in variant records
116   --  d.w  Do not check for infinite loops
117   --  d.x  No exception handlers
118   --  d.y
119   --  d.z  Restore previous support for frontend handling of Inline_Always
120
121   --  d.A  Read/write Aspect_Specifications hash table to tree
122   --  d.B
123   --  d.C  Generate concatenation call, do not generate inline code
124   --  d.D  Disable errors on use of overriding keyword in Ada 95 mode
125   --  d.E  Turn selected errors into warnings
126   --  d.F  Debug mode for GNATprove
127   --  d.G  Ignore calls through generic formal parameters for elaboration
128   --  d.H
129   --  d.I  Do not ignore enum representation clauses in CodePeer mode
130   --  d.J  Disable parallel SCIL generation mode
131   --  d.K
132   --  d.L  Depend on back end for limited types in if and case expressions
133   --  d.M  Relaxed RM semantics
134   --  d.N  Add node to all entities
135   --  d.O  Dump internal SCO tables
136   --  d.P  Previous (non-optimized) handling of length comparisons
137   --  d.Q  Previous (incomplete) style check for binary operators
138   --  d.R  Restrictions in ali files in positional form
139   --  d.S  Force Optimize_Alignment (Space)
140   --  d.T  Force Optimize_Alignment (Time)
141   --  d.U  Ignore indirect calls for static elaboration
142   --  d.V
143   --  d.W  Print out debugging information for Walk_Library_Items
144   --  d.X  Old treatment of indexing aspects
145   --  d.Y
146   --  d.Z  Do not enable expansion in configurable run-time mode
147
148   --  d1   Error msgs have node numbers where possible
149   --  d2   Eliminate error flags in verbose form error messages
150   --  d3   Dump bad node in Comperr on an abort
151   --  d4   Inhibit automatic krunch of predefined library unit files
152   --  d5   Debug output for tree read/write
153   --  d6   Default access unconstrained to thin pointers
154   --  d7   Suppress version/source stamp/compilation time for -gnatv/-gnatl
155   --  d8   Force opposite endianness in packed stuff
156   --  d9   Allow lock free implementation
157
158   --  d.1  Enable unnesting of nested procedures
159   --  d.2  Allow statements in declarative part
160   --  d.3
161   --  d.4
162   --  d.5
163   --  d.6
164   --  d.7
165   --  d.8
166   --  d.9
167
168   --  Debug flags for binder (GNATBIND)
169
170   --  da  All links (including internal units) listed if there is a cycle
171   --  db  Output information from Better_Choice
172   --  dc  List units as they are chosen
173   --  dd
174   --  de  Elaboration dependencies including system units
175   --  df
176   --  dg
177   --  dh
178   --  di  Ignore_Errors mode for reading ali files
179   --  dj
180   --  dk
181   --  dl
182   --  dm
183   --  dn  List details of manipulation of Num_Pred values
184   --  do  Use old preference for elaboration order
185   --  dp
186   --  dq
187   --  dr
188   --  ds
189   --  dt
190   --  du  List units as they are acquired
191   --  dv
192   --  dw
193   --  dx  Force binder to read xref information from ali files
194   --  dy
195   --  dz
196
197   --  Debug flags used in package Make and its clients (e.g. GNATMAKE)
198
199   --  da
200   --  db
201   --  dc
202   --  dd
203   --  de
204   --  df  Only output file names, not path names, in log
205   --  dg
206   --  dh  Generate listing showing loading of name table hash chains
207   --  di
208   --  dj
209   --  dk
210   --  dl
211   --  dm  Display the number of maximum simultaneous compilations
212   --  dn  Do not delete temp files created by gnatmake
213   --  do
214   --  dp  Prints the contents of the Q used by Make.Compile_Sources
215   --  dq  Prints source files as they are enqueued and dequeued
216   --  dr
217   --  ds
218   --  dt  Display time stamps when there is a mismatch
219   --  du  List units as their ali files are acquired
220   --  dv
221   --  dw  Prints the list of units withed by the unit currently explored
222   --  dx
223   --  dy
224   --  dz
225
226   --------------------------------------------
227   -- Documentation for Compiler Debug Flags --
228   --------------------------------------------
229
230   --  da   Generate messages tracking semantic analyzer progress. A message
231   --       is output showing each node as it gets analyzed, expanded,
232   --       resolved, or evaluated. This option is useful for finding out
233   --       exactly where a bomb during semantic analysis is occurring.
234
235   --  db   In Exp_Dbug, certain type names are encoded to include debugging
236   --       information. This debug switch causes lines to be output showing
237   --       the encodings used.
238
239   --  dc   List names of units as they are compiled. One line of output will
240   --       be generated at the start of compiling each unit (package or
241   --       subprogram).
242
243   --  dd   Dynamic allocation of tables messages generated. Each time a
244   --       table is reallocated, a line is output indicating the expansion.
245
246   --  de   List the entity table
247
248   --  df   Full tree/source print (includes withed units). Normally the tree
249   --       output (dt) or recreated source output (dg,do,ds) includes only
250   --       the main unit. If df is set, then the output in either case
251   --       includes all compiled units (see also dg,do,ds,dt). Note that to
252   --       be effective, this switch must be used in combination with one or
253   --       more of dt, dg, do or ds.
254
255   --  dg   Print the source recreated from the generated tree. In the case
256   --       where the tree has been rewritten this output includes only the
257   --       generated code, not the original code (see also df,do,ds,dz).
258   --       This flag differs from -gnatG in that the output also includes
259   --       non-source generated null statements, and freeze nodes, which
260   --       are normally omitted in -gnatG mode.
261
262   --  dh   Generates a table at the end of a compilation showing how the hash
263   --       table chains built by the Namet package are loaded. This is useful
264   --       in ensuring that the hashing algorithm (in Namet.Hash) is working
265   --       effectively with typical sets of program identifiers.
266
267   --  di   Generate messages for visibility linking/delinking
268
269   --  dj   Suppress "junk null check" for access parameters. This flag permits
270   --       Ada programs to pass null parameters to access parameters, and to
271   --       explicitly check such access values against the null literal.
272   --       Neither of these is valid Ada, but both were allowed in versions of
273   --       GNAT before 3.10, so this switch can ease the transition process.
274
275   --  dk   Immediate kill on abort. Normally on an abort (i.e. a call to
276   --       Comperr.Compiler_Abort), the GNATBUG message is not given if
277   --       there is a previous error. This debug switch bypasses this test
278   --       and gives the message unconditionally (useful for debugging).
279
280   --  dl   Generate unit load trace messages. A line of traceback output is
281   --       generated each time a request is made to the library manager to
282   --       load a new unit.
283
284   --  dn   Generate messages for node/list allocation. Each time a node or
285   --       list header is allocated, a line of output is generated. Certain
286   --       other basic tree operations also cause a line of output to be
287   --       generated. This option is useful in seeing where the parser is
288   --       blowing up.
289
290   --  do   Print the source recreated from the generated tree. In the case
291   --       where the tree has been rewritten, this output includes only the
292   --       original code, not the generated code (see also df,dg,ds,dz).
293
294   --  dp   Generate messages for parser scope stack push/pops. A line of
295   --       output by the parser each time the parser scope stack is either
296   --       pushed or popped. Useful in debugging situations where the
297   --       parser scope stack ends up incorrectly synchronized
298
299   --  dq   In layout version 1.38, 2002/01/12, a circuit was implemented
300   --       to give decent default alignment to short records that had no
301   --       specific alignment set. This debug option restores the previous
302   --       behavior of giving such records poor alignments, typically 1.
303   --       This may be useful in dealing with transition.
304
305   --  dr   Generate parser resynchronization messages. Normally the parser
306   --       resynchronizes quietly. With this debug option, two messages
307   --       are generated, one when the parser starts a resynchronization
308   --       skip, and another when it resumes parsing. Useful in debugging
309   --       inadequate error recovery situations.
310
311   --  ds   Print the source recreated from the generated tree. In the case
312   --       where the tree has been rewritten this output includes both the
313   --       generated code and the original code with the generated code
314   --       being enlosed in curly brackets (see also df,do,ds,dz)
315
316   --  dt   Print full tree. The generated tree is output (see also df,dy)
317
318   --  du   Uncheck categorization pragmas. This debug switch causes the
319   --       categorization pragmas (Pure, Preelaborate etc) to be ignored
320   --       so that normal checks are not made (this is particularly useful
321   --       for adding temporary debugging code to units that have pragmas
322   --       that are inconsistent with the debugging code added.
323
324   --  dv   Output trace of overload resolution. Outputs messages for
325   --       overload attempts that involve cascaded errors, or where
326   --       an interepretation is incompatible with the context.
327
328   --  dw   Write semantic scope stack messages. Each time a scope is created
329   --       or removed, a message is output (see the Sem_Ch8.Push_Scope and
330   --       Sem_Ch8.Pop_Scope subprograms).
331
332   --  dx   Force expansion on, even if no code being generated. Normally the
333   --       expander is inhibited if no code is generated. This switch forces
334   --       expansion to proceed normally even if the backend is not being
335   --       called. This is particularly useful for debugging purposes when
336   --       using the front-end only version of the compiler (which normally
337   --       would never do any expansion).
338
339   --  dy   Print tree of package Standard. Normally the tree print out does
340   --       not include package Standard, even if the -df switch is set. This
341   --       switch forces output of the internal tree built for Standard.
342
343   --  dz   Print source of package Standard. Normally the source print out
344   --       does not include package Standard, even if the -df switch is set.
345   --       This switch forces output of the source recreated from the internal
346   --       tree built for Standard. Note that this differs from -gnatS in
347   --       that it prints from the actual tree using the normal Sprint
348   --       circuitry for printing trees.
349
350   --  dA   Forces output of representation information, including full
351   --       information for all internal type and object entities, as well
352   --       as all user defined type and object entities including private
353   --       and incomplete types. This debug switch also automatically sets
354   --       the equivalent of -gnatR3m.
355
356   --  dB   Output debug encodings for types and variants. See Exp_Dbug for
357   --       exact form of the generated output.
358
359   --  dC   Output trace information showing the decisions made during
360   --       check suppression activity in unit Checks.
361
362   --  dD   Delete new elaboration checks. This flag causes GNAT to return
363   --       to the 3.13a elaboration semantics, and to suppress the fixing
364   --       of two bugs. The first is in the context of inner routines in
365   --       dynamic elaboration mode, when the subprogram we are in was
366   --       called at elaboration time by a unit that was also compiled with
367   --       dynamic elaboration checks. In this case, if A calls B calls C,
368   --       and all are in different units, we need an elaboration check at
369   --       each call. These nested checks were only put in recently (see
370   --       version 1.80 of Sem_Elab) and we provide this debug flag to
371   --       revert to the previous behavior in case of regressions. The
372   --       other behavior reverted by this flag is the treatment of the
373   --       Elaborate_Body pragma in static elaboration mode. This used to
374   --       be treated as not needing elaboration checking, but in fact in
375   --       general Elaborate_All is still required because of nested calls.
376
377   --  dE   Apply compile time elaboration checking for with relations between
378   --       predefined units. Normally no checks are made (it seems that at
379   --       least on the SGI, such checks run into trouble).
380
381   --  dF   Front end data layout enabled. Normally front end data layout
382   --       is only enabled if the target parameter Backend_Layout is False.
383   --       This debugging switch enables it unconditionally.
384
385   --  dG   Generate all warnings. Normally Errout suppresses warnings on
386   --       units that are not part of the main extended source, and also
387   --       suppresses warnings on instantiations in the main extended
388   --       source that duplicate warnings already posted on the template.
389   --       This switch stops both kinds of deletion and causes Errout to
390   --       post all warnings sent to it.
391
392   --  dH   Inhibit call to gigi. This is useful for testing front end data
393   --       layout, and may be useful in other debugging situations where
394   --       you do not want gigi to intefere with the testing.
395
396   --  dI   Inhibit internal name numbering in gnatDG listing. Any sequence of
397   --       the form <uppercase-letter><digits><lowercase-letter> appearing in
398   --       a name is replaced by <uppercase-letter>...<lowercase-letter>. This
399   --       is used in the fixed bugs run to minimize system and version
400   --       dependency in filed -gnatD or -gnatG output.
401
402   --  dJ   Generate debugging trace output for the JGNAT back end. This
403   --       consists of symbolic Java Byte Code sequences for all generated
404   --       classes plus additional information to indicate local variables
405   --       and methods.
406
407   --  dK   Kill all error messages. This debug flag suppresses the output
408   --       of all error messages. It is used in regression tests where the
409   --       error messages are target dependent and irrelevant.
410
411   --  dL   Output trace information on elaboration checking. This debug
412   --       switch causes output to be generated showing each call or
413   --       instantiation as it is checked, and the progress of the recursive
414   --       trace through calls at elaboration time.
415
416   --  dM   Assume all variables have been modified, and ignore current value
417   --       indications. This debug flag disconnects the tracking of constant
418   --       values (see Exp_Ch2.Expand_Current_Value).
419
420   --  dN   Do not generate file name information in exception messages
421
422   --  dO   Output immediate error messages. This causes error messages to
423   --       be output as soon as they are generated (disconnecting several
424   --       circuits for improvement of messages, deletion of duplicate
425   --       messages etc). Useful to diagnose compiler bombs caused by
426   --       erroneous handling of error situations
427
428   --  dP   Do not check for controlled objects in preelaborable packages.
429   --       RM 10.2.1(9) forbids the use of library level controlled objects
430   --       in preelaborable packages, but this restriction is a huge pain,
431   --       especially in the predefined library units.
432
433   --  dR   Bypass the check for a proper version of s-rpc being present
434   --       to use the -gnatz? switch. This allows debugging of the use
435   --       of stubs generation without needing to have GLADE (or some
436   --       other PCS  installed).
437
438   --  dS   Omit conversion of fpt numbers to exact machine numbers in
439   --       non-static evaluation contexts (see Check_Non_Static_Context).
440   --       This is intended for testing out timing problems with this
441   --       conversion circuit.
442
443   --  dT   Similar to dS, but omits the conversions only in the case where
444   --       the parent is not a constant declaration.
445
446   --  dU   Enable garbage collection of unreachable entities. This enables
447   --       both the reachability analysis and changing the Is_Public and
448   --       Is_Eliminated flags.
449
450   --  dV   Enable viewing of all symbols in debugger. Causes debug information
451   --       to be generated for all symbols, including internal symbols. This
452   --       is enabled by default for -gnatD, but this switch allows this to
453   --       be enabled without generating modified source files. Note that the
454   --       use of -gnatdV ensures in the dwarf/elf case that all symbols that
455   --       are present in the elf tables are also in the dwarf tables (which
456   --       seems to be required by some tools). Another effect of dV is to
457   --       generate full qualified names, including internal names generated
458   --       for blocks and loops.
459
460   --  dW   Disable warnings when a possibly uninitialized scalar value is
461   --       passed to an IN OUT parameter of a procedure. This usage is a
462   --       quite improper bounded error [erroneous in Ada 83] situation,
463   --       and would normally generate a warning. However, to ease the
464   --       task of transitioning incorrect legacy code, we provide this
465   --       undocumented feature for suppressing these warnings.
466
467   --  dY   Enable configurable run-time mode, just as though the System file
468   --       had Configurable_Run_Time_Mode set to True. This is useful in
469   --       testing high integrity mode.
470
471   --  dZ   Generate listing showing the contents of the dispatch tables. Each
472   --       line has an internally generated number used for references between
473   --       tagged types and primitives. For each primitive the output has the
474   --       following fields:
475   --
476   --         - Letter 'P' or letter 's': The former indicates that this
477   --           primitive will be located in a primary dispatch table. The
478   --           latter indicates that it will be located in a secondary
479   --           dispatch table.
480   --
481   --         - Name of the primitive. In case of predefined Ada primitives
482   --           the text "(predefined)" is added before the name, and these
483   --           acronyms are used: SR (Stream_Read), SW (Stream_Write), SI
484   --           (Stream_Input), SO (Stream_Output), DA (Deep_Adjust), DF
485   --           (Deep_Finalize). In addition Oeq identifies the equality
486   --           operator, and "_assign" the assignment.
487   --
488   --         - If the primitive covers interface types, two extra fields
489   --           referencing other primitives are generated: "Alias" references
490   --           the primitive of the tagged type that covers an interface
491   --           primitive, and "AI_Alias" references the covered interface
492   --           primitive.
493   --
494   --         - The expression "at #xx" indicates the slot of the dispatch
495   --           table occupied by such primitive in its corresponding primary
496   --           or secondary dispatch table.
497   --
498   --         - In case of abstract subprograms the text "is abstract" is
499   --           added at the end of the line.
500
501   --  d.a  Force Target_Strict_Alignment to True, even on targets where it
502   --       would normally be false. Can be used for testing strict alignment
503   --       circuitry in the compiler.
504
505   --  d.b  Dump back end types. During Create_Standard, the back end is
506   --       queried for all available types. This option shows them.
507
508   --  d.c  Generate inline concatenation, instead of calling one of the
509   --       System.Concat_n.Str_Concat_n routines in cases where the latter
510   --       routines would normally be called.
511
512   --  d.d  Disable atomic synchronization for all atomic variable references.
513   --       Pragma Enable_Atomic_Synchronization is ignored.
514
515   --  d.e  Enable atomic synchronization for all atomic variable references.
516   --       Pragma Disable_Atomic_Synchronization is ignored, and also the
517   --       compiler switch -gnated is ignored.
518
519   --  d.f  Suppress folding of static expressions. This of course results
520   --       in seriously non-conforming behavior, but is useful sometimes
521   --       when tracking down handling of complex expressions.
522
523   --  d.g  Enables conversion of a raise statement into a goto when the
524   --       relevant handler is statically determinable. For now we only try
525   --       this if this debug flag is set. Later we will enable this more
526   --       generally by default.
527
528   --  d.h  Minimize the creation of public internal symbols for concatenation
529   --       by enforcing a secondary stack-like handling of the final result.
530   --       The target of the concatenation is thus constrained in place and
531   --       initialized with the result instead of acting as its alias.
532
533   --  d.i  Ignore all occurrences of pragma Warnings in the sources. This can
534   --       be used in particular to disable Warnings (Off) to check if any of
535   --       these statements are inappropriate.
536
537   --  d.j  Generate listing of frontend inlined calls and inline calls passed
538   --       to the backend. This is useful to locate skipped calls that must be
539   --       inlined by the frontend.
540
541   --  d.l  Use Ada 95 semantics for limited function returns. This may be
542   --       used to work around the incompatibility introduced by AI-318-2.
543   --       It is useful only in -gnat05 mode.
544
545   --  d.m  When -gnatl is used, the normal output includes full listings of
546   --       all files in the extended main source (body/spec/subunits). If this
547   --       debug switch is used, then the full listing is given only for the
548   --       main source (this corresponds to a previous behavior of -gnatl and
549   --       is used for running the ACATS tests).
550
551   --  d.n  Print source file names as they are loaded. This is useful if the
552   --       compiler has a bug -- these are the files that need to be included
553   --       in a bug report.
554
555   --  d.o  Generate listing showing the IL instructions generated by the .NET
556   --       compiler for each subprogram.
557
558   --  d.p  Enable the .NET CIL verifier. During development the verifier is
559   --       disabled by default and this flag is used to enable it. In the
560   --       future we will reverse this functionality.
561
562   --  d.r  Forces the flag OK_To_Reorder_Components to be set in all record
563   --       base types that have no discriminants.
564
565   --  d.s  Normally the compiler expands slice moves into loops if overlap
566   --       might be possible. This debug flag inhibits that expansion, and
567   --       the back end is expected to use an appropriate routine to handle
568   --       overlap, based on Forward_OK and Backwards_OK flags.
569
570   --  d.t  The compiler has been modified (a fairly extensive modification)
571   --       to generate static dispatch tables for library level tagged types.
572   --       This debug switch disables this modification and reverts to the
573   --       previous dynamic construction of tables. It is there as a possible
574   --       work around if we run into trouble with the new implementation.
575
576   --  d.u  Sets Modify_Tree_For_C mode in which tree is modified to make it
577   --       easier to generate code using a C compiler.
578
579   --  d.v  Forces the flag OK_To_Reorder_Components to be set in all record
580   --       base types that have at least one discriminant (v = variant).
581
582   --  d.w  This flag turns off the scanning of loops to detect possible
583   --       infinite loops.
584
585   --  d.x  No exception handlers in generated code. This causes exception
586   --       handlers to be eliminated from the generated code. They are still
587   --       fully compiled and analyzed, they just get eliminated from the
588   --       code generation step.
589
590   --  d.z  Restore previous front-end support for Inline_Always. In default
591   --       mode, for targets that use the GCC back end (i.e. currently all
592   --       targets except AAMP, .NET, JVM, and GNATprove), Inline_Always is
593   --       handled by the back end. Use of this switch restores the previous
594   --       handling of Inline_Always by the front end on such targets. For the
595   --       targets that do not use the GCC back end, this switch is ignored.
596
597   --  d.A  There seems to be a problem with ASIS if we activate the circuit
598   --       for reading and writing the aspect specification hash table, so
599   --       for now, this is controlled by the debug flag d.A. The hash table
600   --       is only written and read if this flag is set.
601
602   --  d.C  Generate call to System.Concat_n.Str_Concat_n routines in cases
603   --       where we would normally generate inline concatenation code.
604
605   --  d.D  For compatibility with some Ada 95 compilers implementing only
606   --       one feature of Ada 2005 (overriding keyword), disable errors on use
607   --       of overriding keyword in Ada 95 mode.
608
609   --  d.E  Turn selected errors into warnings. This debug switch causes a
610   --       specific set of error messages into warnings. Setting this switch
611   --       causes Opt.Error_To_Warning to be set to True. The intention is
612   --       that this be used for messages representing upwards incompatible
613   --       changes to Ada 2012 that cause previously correct programs to be
614   --       treated as illegal now. The following cases are affected:
615   --
616   --          Errors relating to overlapping subprogram parameters for cases
617   --          other than IN OUT parameters to functions.
618   --
619   --          Errors relating to the new rules about not defining equality
620   --          too late so that composition of equality can be assured.
621   --
622   --          Errors relating to overriding indicators on protected subprogram
623   --          bodies (not an Ada 2012 incompatibility, but might cause errors
624   --          for existing programs assuming they were legal because GNAT
625   --          formerly allowed them).
626
627   --  d.F  Sets GNATprove_Mode to True. This allows debugging the frontend in
628   --       the special mode used by GNATprove.
629
630   --  d.G  Previously the compiler ignored calls via generic formal parameters
631   --       when doing the analysis for the static elaboration model. This is
632   --       now fixed, but we provide this debug flag to revert to the previous
633   --       situation of ignoring such calls to aid in transition.
634
635   --  d.I  Do not ignore enum representation clauses in CodePeer mode.
636   --       The default of ignoring representation clauses for enumeration
637   --       types in CodePeer is good for the majority of Ada code, but in some
638   --       cases being able to change this default might be useful to remove
639   --       some false positives.
640
641   --  d.J  Disable parallel SCIL generation. Normally SCIL file generation is
642   --       done in parallel to speed processing. This switch disables this
643   --       behavior.
644
645   --  d.L  Normally the front end generates special expansion for conditional
646   --       expressions of a limited type. This debug flag removes this special
647   --       case expansion, leaving it up to the back end to handle conditional
648   --       expressions correctly.
649
650   --  d.M  Relaxed RM semantics. This flag sets Opt.Relaxed_RM_Semantics
651   --       See Opt.Relaxed_RM_Semantics for more details.
652
653   --  d.N  Enlarge entities by one node (but don't attempt to use this extra
654   --       node for storage of any flags or fields). This can be used to do
655   --       experiments on the impact of increasing entity sizes.
656
657   --  d.O  Dump internal SCO tables. Before outputting the SCO information to
658   --       the ALI file, the internal SCO tables (SCO_Table/SCO_Unit_Table)
659   --       are dumped for debugging purposes.
660
661   --  d.P  Previous non-optimized handling of length comparisons. Setting this
662   --       flag inhibits the effect of Optimize_Length_Comparison in Exp_Ch4.
663   --       This is there in case we find a situation where the optimization
664   --       malfunctions, to provide a work around.
665
666   --  d.Q  Previous incomplete style checks for binary operators. Style checks
667   --       for token separation rules were incomplete and have been made
668   --       compliant with the documentation. For example, no warning was
669   --       issued for expressions such as 16-One or "A"&"B". Setting this flag
670   --       inhibits these new checks.
671
672   --  d.R  As documented in lib-writ.ads, restrictions in the ali file can
673   --       have two forms, positional and named. The named notation is the
674   --       current preferred form, but the use of this debug switch will force
675   --       the use of the obsolescent positional form.
676
677   --  d.S  Force Optimize_Alignment (Space) mode as the default
678
679   --  d.T  Force Optimize_Alignment (Time) mode as the default
680
681   --  d.U  Ignore indirect calls for static elaboration. The static
682   --       elaboration model is conservative, especially regarding indirect
683   --       calls. If you say Proc'Access, it will assume you might call
684   --       Proc. This can cause elaboration cycles at bind time. This flag
685   --       reverts to the behavior of earlier compilers, which ignored
686   --       indirect calls.
687
688   --  d.W  Print out debugging information for Walk_Library_Items, including
689   --       the order in which units are walked. This is primarily for use in
690   --       debugging CodePeer mode.
691
692   --  d.X  A previous version of GNAT allowed indexing aspects to be
693   --       redefined on derived container types, while the default iterator
694   --       was inherited from the aprent type. This non-standard extension
695   --       is preserved temporarily for use by the modelling project under
696   --       debug flag d.X.
697
698   --  d.Z  Normally we always enable expansion in configurable run-time mode
699   --       to make sure we get error messages about unsupported features even
700   --       when compiling in -gnatc mode. But expansion is turned off in this
701   --       case if debug flag -gnatd.Z is used. This is to deal with the case
702   --       where we discover difficulties in this new processing.
703
704   --  d1   Error messages have node numbers where possible. Normally error
705   --       messages have only source locations. This option is useful when
706   --       debugging errors caused by expanded code, where the source location
707   --       does not give enough information.
708
709   --  d2   Suppress output of the error position flags for verbose form error
710   --       messages. The messages are still interspersed in the listing, but
711   --       without any error flags or extra blank lines. Also causes an extra
712   --       <<< to be output at the right margin. This is intended to be the
713   --       easiest format for checking conformance of ACATS B tests. This
714   --       flag also suppresses the additional messages explaining why a
715   --       non-static expression is non-static (see Sem_Eval.Why_Not_Static).
716   --       This avoids having to worry about these messages in ACATS testing.
717
718   --  d3   Causes Comperr to dump the contents of the node for which an abort
719   --       was detected (normally only the Node_Id of the node is output).
720
721   --  d4   Inhibits automatic krunching of predefined library unit file names.
722   --       Normally, as described in the spec of package Krunch, such files
723   --       are automatically krunched to 8 characters, with special treatment
724   --       of the prefixes Ada, System, and Interfaces. Setting this debug
725   --       switch disables this special treatment.
726
727   --  d5   Causes the tree read/write circuit to output detailed information
728   --       tracking the data that is read and written element by element.
729
730   --  d6   Normally access-to-unconstrained-array types are represented
731   --       using fat (double) pointers. Using this debug flag causes them
732   --       to default to thin. This can be used to test the performance
733   --       implications of using thin pointers, and also to test that the
734   --       compiler functions correctly with this choice.
735
736   --  d7   Normally a -gnatl or -gnatv listing includes the time stamp of the
737   --       source file and the time of the compilation. This debug flag can
738   --       be used to suppress this output, and also suppresses the message
739   --       with the version of the compiler. This is useful for regression
740   --       tests which need to have consistent output.
741
742   --  d8   This forces the packed stuff to generate code assuming the
743   --       opposite endianness from the actual correct value. Useful in
744   --       testing out code generation from the packed routines.
745
746   --  d9   This allows lock free implementation for protected objects
747   --       (see Exp_Ch9).
748
749   --  d.1  Sets Opt.Unnest_Subprogram_Mode to enable unnesting of subprograms.
750   --       This special pass does not actually unnest things, but it ensures
751   --       that a nested procedure does not contain any uplevel references.
752   --       See spec of Exp_Unst for full details.
753
754   --  d.2  Allow statements within declarative parts. This is not usually
755   --       allowed, but in some debugging contexts (e.g. testing the circuit
756   --       for unnesting of procedures), it is useful to allow this.
757
758   ------------------------------------------
759   -- Documentation for Binder Debug Flags --
760   ------------------------------------------
761
762   --  da  Normally if there is an elaboration circularity, then in describing
763   --      the cycle, links involving internal units are omitted, since they
764   --      are irrelevant and confusing. This debug flag causes all links to
765   --      be listed, and is useful when diagnosing circularities introduced
766   --      by incorrect changes to the run-time library itself.
767
768   --  db  Output debug information from Better_Choice in Binde, which uses
769   --      various heuristics to determine elaboration order in cases where
770   --      multiple orders are valid.
771
772   --  dc  List units as they are chosen. As units are selected for addition to
773   --      the elaboration order, a line of output is generated showing which
774   --      unit has been selected.
775
776   --  de  Similar to the effect of -e (output complete list of elaboration
777   --      dependencies) except that internal units are included in the
778   --      listing.
779
780   --  di  Normally gnatbind calls Read_Ali with Ignore_Errors set to
781   --      False, since the binder really needs correct version ALI
782   --      files to do its job. This debug flag causes Ignore_Errors
783   --      mode to be set for the binder (and is particularly useful
784   --      for testing ignore errors mode).
785
786   --  dn  List details of manipulation of Num_Pred values during execution of
787   --      the algorithm used to determine a correct order of elaboration. This
788   --      is useful in diagnosing any problems in its behavior.
789
790   --  do  Use old elaboration order preference. The new preference rules
791   --      prefer specs with no bodies to specs with bodies, and between two
792   --      specs with bodies, prefers the one whose body is closer to being
793   --      able to be elaborated. This is a clear improvement, but we provide
794   --      this debug flag in case of regressions.
795
796   --  du  List unit name and file name for each unit as it is read in
797
798   --  dx  Force the binder to read (and then ignore) the xref information
799   --      in ali files (used to check that read circuit is working OK).
800
801   --------------------------------------------
802   -- Documentation for gnatmake Debug Flags --
803   --------------------------------------------
804
805   --  df  Only output file names, not path names, in log
806
807   --  dh  Generate listing showing loading of name table hash chains,
808   --      same as for the compiler.
809
810   --  dm  Issue a message indicating the maximum number of simultaneous
811   --      compilations.
812
813   --  dn  Do not delete temporary files created by gnatmake at the end
814   --      of execution, such as temporary config pragma files, mapping
815   --      files or project path files. This debug switch is equivalent to
816   --      the standard switch --keep-temp-files. We retain the debug switch
817   --      for back compatibility with past usage.
818
819   --  dp  Prints the Q used by routine Make.Compile_Sources every time
820   --      we go around the main compile loop of Make.Compile_Sources
821
822   --  dq  Prints source files as they are enqueued and dequeued in the Q
823   --      used by routine Make.Compile_Sources. Useful to figure out the
824   --      order in which sources are recompiled.
825
826   --  dt  When a time stamp mismatch has been found for an ALI file,
827   --      display the source file name, the time stamp expected and
828   --      the time stamp found.
829
830   --  du  List unit name and file name for each unit as it is read in
831
832   --  dw  Prints the list of units withed by the unit currently explored
833   --      during the main loop of Make.Compile_Sources.
834
835   ---------------------------------------------
836   -- Documentation for gprbuild Debug Flags  --
837   ---------------------------------------------
838
839   --  dm  Display the maximum number of simultaneous compilations.
840
841   --  dn  Do not delete temporary files created by gprbuild at the end
842   --      of execution, such as temporary config pragma files, mapping
843   --      files or project path files. This debug switch is equivalent to
844   --      the standard switch --keep-temp-files. We retain the debug switch
845   --      for back compatibility with past usage.
846
847   --  dt  When a time stamp mismatch has been found for an ALI file,
848   --      display the source file name, the time stamp expected and
849   --      the time stamp found.
850
851   --------------------
852   -- Set_Debug_Flag --
853   --------------------
854
855   procedure Set_Debug_Flag (C : Character; Val : Boolean := True) is
856      subtype Dig is Character range '1' .. '9';
857      subtype LLet is Character range 'a' .. 'z';
858      subtype ULet is Character range 'A' .. 'Z';
859
860   begin
861      if C in Dig then
862         case Dig (C) is
863            when '1' =>
864               Debug_Flag_1 := Val;
865            when '2' =>
866               Debug_Flag_2 := Val;
867            when '3' =>
868               Debug_Flag_3 := Val;
869            when '4' =>
870               Debug_Flag_4 := Val;
871            when '5' =>
872               Debug_Flag_5 := Val;
873            when '6' =>
874               Debug_Flag_6 := Val;
875            when '7' =>
876               Debug_Flag_7 := Val;
877            when '8' =>
878               Debug_Flag_8 := Val;
879            when '9' =>
880               Debug_Flag_9 := Val;
881         end case;
882
883      elsif C in ULet then
884         case ULet (C) is
885            when 'A' =>
886               Debug_Flag_AA := Val;
887            when 'B' =>
888               Debug_Flag_BB := Val;
889            when 'C' =>
890               Debug_Flag_CC := Val;
891            when 'D' =>
892               Debug_Flag_DD := Val;
893            when 'E' =>
894               Debug_Flag_EE := Val;
895            when 'F' =>
896               Debug_Flag_FF := Val;
897            when 'G' =>
898               Debug_Flag_GG := Val;
899            when 'H' =>
900               Debug_Flag_HH := Val;
901            when 'I' =>
902               Debug_Flag_II := Val;
903            when 'J' =>
904               Debug_Flag_JJ := Val;
905            when 'K' =>
906               Debug_Flag_KK := Val;
907            when 'L' =>
908               Debug_Flag_LL := Val;
909            when 'M' =>
910               Debug_Flag_MM := Val;
911            when 'N' =>
912               Debug_Flag_NN := Val;
913            when 'O' =>
914               Debug_Flag_OO := Val;
915            when 'P' =>
916               Debug_Flag_PP := Val;
917            when 'Q' =>
918               Debug_Flag_QQ := Val;
919            when 'R' =>
920               Debug_Flag_RR := Val;
921            when 'S' =>
922               Debug_Flag_SS := Val;
923            when 'T' =>
924               Debug_Flag_TT := Val;
925            when 'U' =>
926               Debug_Flag_UU := Val;
927            when 'V' =>
928               Debug_Flag_VV := Val;
929            when 'W' =>
930               Debug_Flag_WW := Val;
931            when 'X' =>
932               Debug_Flag_XX := Val;
933            when 'Y' =>
934               Debug_Flag_YY := Val;
935            when 'Z' =>
936               Debug_Flag_ZZ := Val;
937         end case;
938
939      else
940         case LLet (C) is
941            when 'a' =>
942               Debug_Flag_A := Val;
943            when 'b' =>
944               Debug_Flag_B := Val;
945            when 'c' =>
946               Debug_Flag_C := Val;
947            when 'd' =>
948               Debug_Flag_D := Val;
949            when 'e' =>
950               Debug_Flag_E := Val;
951            when 'f' =>
952               Debug_Flag_F := Val;
953            when 'g' =>
954               Debug_Flag_G := Val;
955            when 'h' =>
956               Debug_Flag_H := Val;
957            when 'i' =>
958               Debug_Flag_I := Val;
959            when 'j' =>
960               Debug_Flag_J := Val;
961            when 'k' =>
962               Debug_Flag_K := Val;
963            when 'l' =>
964               Debug_Flag_L := Val;
965            when 'm' =>
966               Debug_Flag_M := Val;
967            when 'n' =>
968               Debug_Flag_N := Val;
969            when 'o' =>
970               Debug_Flag_O := Val;
971            when 'p' =>
972               Debug_Flag_P := Val;
973            when 'q' =>
974               Debug_Flag_Q := Val;
975            when 'r' =>
976               Debug_Flag_R := Val;
977            when 's' =>
978               Debug_Flag_S := Val;
979            when 't' =>
980               Debug_Flag_T := Val;
981            when 'u' =>
982               Debug_Flag_U := Val;
983            when 'v' =>
984               Debug_Flag_V := Val;
985            when 'w' =>
986               Debug_Flag_W := Val;
987            when 'x' =>
988               Debug_Flag_X := Val;
989            when 'y' =>
990               Debug_Flag_Y := Val;
991            when 'z' =>
992               Debug_Flag_Z := Val;
993         end case;
994      end if;
995   end Set_Debug_Flag;
996
997   ---------------------------
998   -- Set_Dotted_Debug_Flag --
999   ---------------------------
1000
1001   procedure Set_Dotted_Debug_Flag (C : Character; Val : Boolean := True) is
1002      subtype Dig is Character range '1' .. '9';
1003      subtype LLet is Character range 'a' .. 'z';
1004      subtype ULet is Character range 'A' .. 'Z';
1005
1006   begin
1007      if C in Dig then
1008         case Dig (C) is
1009            when '1' =>
1010               Debug_Flag_Dot_1 := Val;
1011            when '2' =>
1012               Debug_Flag_Dot_2 := Val;
1013            when '3' =>
1014               Debug_Flag_Dot_3 := Val;
1015            when '4' =>
1016               Debug_Flag_Dot_4 := Val;
1017            when '5' =>
1018               Debug_Flag_Dot_5 := Val;
1019            when '6' =>
1020               Debug_Flag_Dot_6 := Val;
1021            when '7' =>
1022               Debug_Flag_Dot_7 := Val;
1023            when '8' =>
1024               Debug_Flag_Dot_8 := Val;
1025            when '9' =>
1026               Debug_Flag_Dot_9 := Val;
1027         end case;
1028
1029      elsif C in ULet then
1030         case ULet (C) is
1031            when 'A' =>
1032               Debug_Flag_Dot_AA := Val;
1033            when 'B' =>
1034               Debug_Flag_Dot_BB := Val;
1035            when 'C' =>
1036               Debug_Flag_Dot_CC := Val;
1037            when 'D' =>
1038               Debug_Flag_Dot_DD := Val;
1039            when 'E' =>
1040               Debug_Flag_Dot_EE := Val;
1041            when 'F' =>
1042               Debug_Flag_Dot_FF := Val;
1043            when 'G' =>
1044               Debug_Flag_Dot_GG := Val;
1045            when 'H' =>
1046               Debug_Flag_Dot_HH := Val;
1047            when 'I' =>
1048               Debug_Flag_Dot_II := Val;
1049            when 'J' =>
1050               Debug_Flag_Dot_JJ := Val;
1051            when 'K' =>
1052               Debug_Flag_Dot_KK := Val;
1053            when 'L' =>
1054               Debug_Flag_Dot_LL := Val;
1055            when 'M' =>
1056               Debug_Flag_Dot_MM := Val;
1057            when 'N' =>
1058               Debug_Flag_Dot_NN := Val;
1059            when 'O' =>
1060               Debug_Flag_Dot_OO := Val;
1061            when 'P' =>
1062               Debug_Flag_Dot_PP := Val;
1063            when 'Q' =>
1064               Debug_Flag_Dot_QQ := Val;
1065            when 'R' =>
1066               Debug_Flag_Dot_RR := Val;
1067            when 'S' =>
1068               Debug_Flag_Dot_SS := Val;
1069            when 'T' =>
1070               Debug_Flag_Dot_TT := Val;
1071            when 'U' =>
1072               Debug_Flag_Dot_UU := Val;
1073            when 'V' =>
1074               Debug_Flag_Dot_VV := Val;
1075            when 'W' =>
1076               Debug_Flag_Dot_WW := Val;
1077            when 'X' =>
1078               Debug_Flag_Dot_XX := Val;
1079            when 'Y' =>
1080               Debug_Flag_Dot_YY := Val;
1081            when 'Z' =>
1082               Debug_Flag_Dot_ZZ := Val;
1083         end case;
1084
1085      else
1086         case LLet (C) is
1087            when 'a' =>
1088               Debug_Flag_Dot_A := Val;
1089            when 'b' =>
1090               Debug_Flag_Dot_B := Val;
1091            when 'c' =>
1092               Debug_Flag_Dot_C := Val;
1093            when 'd' =>
1094               Debug_Flag_Dot_D := Val;
1095            when 'e' =>
1096               Debug_Flag_Dot_E := Val;
1097            when 'f' =>
1098               Debug_Flag_Dot_F := Val;
1099            when 'g' =>
1100               Debug_Flag_Dot_G := Val;
1101            when 'h' =>
1102               Debug_Flag_Dot_H := Val;
1103            when 'i' =>
1104               Debug_Flag_Dot_I := Val;
1105            when 'j' =>
1106               Debug_Flag_Dot_J := Val;
1107            when 'k' =>
1108               Debug_Flag_Dot_K := Val;
1109            when 'l' =>
1110               Debug_Flag_Dot_L := Val;
1111            when 'm' =>
1112               Debug_Flag_Dot_M := Val;
1113            when 'n' =>
1114               Debug_Flag_Dot_N := Val;
1115            when 'o' =>
1116               Debug_Flag_Dot_O := Val;
1117            when 'p' =>
1118               Debug_Flag_Dot_P := Val;
1119            when 'q' =>
1120               Debug_Flag_Dot_Q := Val;
1121            when 'r' =>
1122               Debug_Flag_Dot_R := Val;
1123            when 's' =>
1124               Debug_Flag_Dot_S := Val;
1125            when 't' =>
1126               Debug_Flag_Dot_T := Val;
1127            when 'u' =>
1128               Debug_Flag_Dot_U := Val;
1129            when 'v' =>
1130               Debug_Flag_Dot_V := Val;
1131            when 'w' =>
1132               Debug_Flag_Dot_W := Val;
1133            when 'x' =>
1134               Debug_Flag_Dot_X := Val;
1135            when 'y' =>
1136               Debug_Flag_Dot_Y := Val;
1137            when 'z' =>
1138               Debug_Flag_Dot_Z := Val;
1139         end case;
1140      end if;
1141   end Set_Dotted_Debug_Flag;
1142
1143end Debug;
1144