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revision 671, Mon Jun 19 02:02:32 2000 UTC revision 684, Tue Jul 11 04:57:48 2000 UTC
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13  Description:  Description:
14  ----------------------------------------------------------------------  ----------------------------------------------------------------------
15  Name: Matthias Blume  Name: Matthias Blume
16    Date: 2000/07/11 13:58:00 JST
17    Tag: blume-20000711-doctypo
18    Description:
19    
20    Fixed a few typos in CM manual.
21    
22    ----------------------------------------------------------------------
23    Name: Allen Leung
24    Date: 2000/06/15 00:38:00
25    Tag: leunga-20000704-sparc-x86
26    
27    1. x86 peephole improvement sp += k; sp -= k => nop  [from John]
28    2. fix to x86 RET bug [found by Dan Grossman]
29    3. sparc assembly bug fix for ticc instructions [found by Fermin]
30    
31       Affects c-- and moby only
32    
33    ----------------------------------------------------------------------
34    Name: Matthias Blume
35    Date: 2000/07/04 15:26:00
36    Tag: blume-20000704-trigger
37    Description:
38    
39    1. Improvements to CM manual.
40    2. SMLofNJ.Internals.BTrace.trigger reinstated as an alternative way
41       of getting a back-trace.  The function, when called, raises an
42       internal exception which explicitly carries the full back-trace history,
43       so it is unaffected by any intervening handle-raise pairs ("trivial"
44       or not).  The interactive loop will print that history once it arrives
45       at top level.
46       Short of having all exceptions implicitly carry the full history, the
47       recommended way of using this facility is:
48         - compile your program with instrumentation "on"
49         - run it, when it raises an exception, look at the history
50         - if the history is "cut off" because of some handler, go and modify
51           your program so that it explicitly calls BTrace.trigger
52         - recompile (still instrumented), and rerun; look at the full history
53    
54    ----------------------------------------------------------------------
55    Name: Matthias Blume
56    Date: 2000/07/03 15:36:00 JST
57    Tag: blume-20000702-manual
58    Description:
59    
60    Small corrections and updates to CM manual.
61    
62    ----------------------------------------------------------------------
63    Name: Matthias Blume
64    Date: 2000/06/29 16:04:00 JST
65    Tag: blume-20000629-yacctool
66    Description:
67    
68    Changes:
69    
70    1. Class "mlyacc" now takes separate arguments to pass options to
71       generated .sml- and .sig-files independently.
72    2. Corresponding CM manual updates.
73    3. BTrace module now also reports call sites.  (However, for loop clusters
74       it only shows from where the cluster was entered.)  There are associated
75       modifications to core.sml, internals.{sig,sml}, btrace.sml, and btimp.sml.
76    
77    ----------------------------------------------------------------------
78    Name: Matthias Blume
79    Date: 2000/06/27 16:51:00 JST
80    Tag: blume-20000627-noweb
81    Description:
82    
83    Changes:
84    
85     1. Implemented "subdir" and "witness" options for noweb tool.
86        This caused some slight internal changes in CM's tool implementation.
87     2. Fixed bug in "tool plugin" mechanism.  This is essentially cleaning
88        some remaining issues from earlier path anchor changes.
89     3. Updated CM manual accordingly.
90    
91     4. Changed implementation of back-tracing so that I now consider it
92        ready for prime-time.
93    
94        In particular, you don't have to explicitly trigger the back-trace
95        anymore.  Instead, if you are running BTrace-instrumented code and
96        there is an uncaught exception (regardless of whether or not it was
97        raised in instrumented code), the top-level evalloop will print
98        the back-trace.
99    
100        Features:
101    
102          - Instrumented and uninstrumented code work together seemlessly.
103            (Of course, uninstrumented code is never mentioned in actual
104             back-traces.)
105    
106          - Asymptotic time- and space-complexity of instrumented code is
107            equal to that of uninstrumented code.  (This means that
108            tail-recursion is preserved by the instrumentation phase.)
109    
110          - Modules whose code has been instrumented in different sessions
111            work together without problem.
112    
113          - There is no penalty whatsoever on uninstrumented code.
114    
115          - There is no penalty on "raise" expressions, even in
116            instrumented code.
117    
118        A potential bug (or perhaps it is a feature, too):
119    
120          A back-trace reaches no further than the outermost instrumented
121          non-trivial "raise".  Here, a "trivial" raise is one that is the
122          sole RHS of a "handle" rule.  Thus, back-traces reach trough
123    
124               <exp> handle e => raise e
125    
126          and even
127    
128               <exp> handle Foo => raise Bar
129    
130          and, of course, through
131    
132               <exp> handle Foo => ...
133    
134         if the exception was not Foo.
135    
136         Back-traces always reach right through any un-instrumented code
137         including any of its "handle" expressions, trivial or not.
138    
139       To try this out, do the following:
140    
141         - Erase all existing binfiles for your program.
142           (You may keep binfiles for those modules where you think you
143            definitely don't need back-tracing.)
144         - Turn on back-trace instrumentation:
145              SMLofNJ.Internals.BTrace.mode (SOME true);
146         - Recompile your program.  (I.e., run "CM.make" or "use".)
147         - You may now turn instrumentation off again (if you want):
148              SMLofNJ.Internals.BTrace.mode (SOME false);
149         - Run your program as usual.  If it raises an exception that
150           reaches the interactive toplevel, then a back-trace will
151           automatically be printed.  After that, the toplevel loop
152           will print the exception history as usual.
153    
154    ----------------------------------------------------------------------
155    Name: Matthias Blume
156    Date: 2000/06/26 09:56:46 JST
157    Tag: blume-20000626-setup
158    Description:
159    
160    CM: - setup-parameter to "sml" added; this can be used to run arbitrary
161          ML code before and after compiling a file (e.g., to set compiler
162          flags)
163    
164    Compiler: - improved btrace API (in core.sml, internals.{sig,sml})
165              - associated changes to btrace.sml (BTrace instrumentation pass)
166              - cleaner implementation of btimp.sml (BTrace tracing and report
167                module)
168    
169    CM manual: * new path encoding documented
170               * description of setup-parameter to "sml" added
171    
172    The biggest user-visible change to back-tracing is that it is no
173    longer necessary to compile all traced modules within the same
174    session.  (This was a real limitation.)
175    
176    ----------------------------------------------------------------------
177    Name: Matthias Blume
178    Date: 2000/06/24 12:40:00 JST
179    Tag: blume-20000624-startup
180    Description:
181    
182    Fixes startup slowdown problem.  (I was calling SrcPath.sync a _tad_
183    bit too often -- to put it mildly. :)
184    
185    ----------------------------------------------------------------------
186    Name: Matthias Blume
187    Date: 2000/06/23 18:20:00 JST
188    Tag: blume-20000623-btrace
189    Description:
190    
191    This updates adds a backtrace facility to aid programmers in debugging
192    their programs.  This involves the following changes:
193    
194    1. Module system/smlnj/init/core.sml (structure _Core) now has hooks for
195       keeping track of the current call stack.  When programs are compiled
196       in a special mode, the compiler will insert calls to these hooks
197       into the user program.
198       "Hook" means that it is possible for different implementations of
199       back-tracing to register themselves (at different times).
200    
201    2. compiler/MiscUtil/profile/btrace.sml implements the annotation phase
202       as an Absyn.dec->Absyn.dec rewrite.  Normally this phase is turned off.
203       It can be turned on using this call:
204         SMLofNJ.Internals.BTrace.mode (SOME true);
205       Turning it off again:
206         SMLofNJ.Internals.BTrace.mode (SOME false);
207       Querying the current status:
208         SMLofNJ.Internals.BTrace.mode NONE;
209       Annotated programs are about twice as big as normal ones, and they
210       run a factor of 2 to 4 slower with a dummy back-trace plugin (one
211       where all hooks do nothing).  The slowdown with a plugin that is
212       actually useful (such as the one supplied by default) is even greater,
213       but in the case of the default plugin it is still only an constant
214       factor (amortized).
215    
216    3. system/Basis/Implementation/NJ/internals.{sig,sml} have been augmented
217       with a sub-structure BTrace for controlling back-tracing.  In particular,
218       the above-mentioned function "mode" controls whether the annotation
219       phase is invoked by the compiler.  Another important function is
220       "trigger": when called it aborts the current execution and causes
221       the top-level loop to print a full back-trace.
222    
223    4. compiler/MiscUtil/profile/btimp.sml is the current default plugin
224       for back-tracing.  It keeps track of the dynamic call stack and in
225       addition to that it keeps a partial history at each "level" of that
226       stack.  For example, if a tail-calls b, b tail-calls c, and c tail-calls
227       d and b (at separate times, dynamically), then the report will show:
228    
229       GOTO   d
230             /c
231       GOTO  \b
232       CALL   a
233    
234       This shows that there was an initial non-tail call of a, then a
235       tail-call to b or c, looping behavior in a cluster of functions that
236       consist of b and c, and then a goto from that cluster (i.e., either from
237       b or from c) to d.
238    
239       Note that (depending on the user program) the amount of information
240       that the back-trace module has to keep track of at each level is bounded
241       by a constant.  Thus, the whole implementation has the same asymptotical
242       complexity as the original program (both in space and in time).
243    
244    5. compiler/TopLevel/interact/evalloop.sml has been modified to
245       handle the special exception SMLofNJ.Internals.BTrace.BTrace
246       which is raised by the "trigger" function mentioned above.
247    
248    Notes on usage:
249    
250    - Annotated code works well together with unannotated code:
251    Unannotated calls simply do not show up at all in the backtrace.
252    
253    - It is not a good idea to let modules that were annotated during
254    different sessions run at the same time.  This is because the compiler
255    chooses small integers to identify individual functions, and there
256    will be clashes if different modules were compiled in separate sessions.
257    (Nothing will crash, and you will even be told about the clashes, but
258    back-trace information will in general not be useful.)
259    
260    - Back-tracing can be confused by callcc and capture.
261    
262    - The only way of getting a back-trace right now is to explicitly
263    invoke the "trigger" function from your user program.  Eventually, we
264    should make every exception carry back-trace information (if
265    available).  But since this creates more overhead at "raise"-time
266    (similar to the current exnHistory overhead), I have not yet
267    implemented this.  (The implementation will be rather easy.)  With
268    exceptions carrying back-trace information, this facility will be even
269    more useful because users don't need to modify their programs...
270    
271    - While it is possible to compile the compiler with back-trace
272    annotations turned on (I did it to get some confidence in
273    correctness), you must make absolutely sure that core.sml and
274    btimp.sml are compiled WITHOUT annotation!  (core.sml cannot actually
275    be compiled with annotation because there is no core access yet, but
276    if you compile btimp.sml with annotation, then the system will go into
277    an infinite recursion and crash.)
278    Since CM currently does not know about BTrace, the only way to turn
279    annotations on and off for different modules of the compiler is to
280    interrupt CMB.make, change the settings, and re-invoke it.  Of course,
281    this is awkward and clumsy.
282    
283    Sample sessions:
284    
285    Standard ML of New Jersey v110.28.1 [FLINT v1.5], June 5, 2000
286    - SMLofNJ.Internals.BTrace.mode (SOME true);
287    [autoloading]
288    [autoloading done]
289    val it = false : bool
290    - structure X = struct
291    -     fun main n = let
292    -         fun a (x, 0) = d x
293    -           | a (x, n) = b (x, n - 1)
294    -         and b (x, n) = c (x, n)
295    -         and c (x, n) = a (x, n)
296    -         and d x = e (x, 3)
297    -         and e (x, 0) = f x
298    -           | e (x, n) = e (x, n - 1)
299    -         and f 0 = SMLofNJ.Internals.BTrace.trigger ()
300    -           | f n = n * g (n - 1)
301    -         and g n = a (n, 3)
302    -     in
303    -         f n
304    -     end
305    - end;
306    structure X : sig val main : int -> int end
307    - X.main 3;
308    *** BACK-TRACE ***
309    GOTO   stdIn:4.2-13.20: X.main[2].f
310    GOTO-( stdIn:4.2-13.20: X.main[2].e
311    GOTO   stdIn:4.2-13.20: X.main[2].d
312         / stdIn:4.2-13.20: X.main[2].a
313         | stdIn:4.2-13.20: X.main[2].b
314    GOTO-\ stdIn:4.2-13.20: X.main[2].c
315    CALL   stdIn:4.2-13.20: X.main[2].g
316    GOTO   stdIn:4.2-13.20: X.main[2].f
317    GOTO-( stdIn:4.2-13.20: X.main[2].e
318    GOTO   stdIn:4.2-13.20: X.main[2].d
319         / stdIn:4.2-13.20: X.main[2].a
320         | stdIn:4.2-13.20: X.main[2].b
321    GOTO-\ stdIn:4.2-13.20: X.main[2].c
322    CALL   stdIn:4.2-13.20: X.main[2].g
323    GOTO   stdIn:4.2-13.20: X.main[2].f
324    GOTO-( stdIn:4.2-13.20: X.main[2].e
325    GOTO   stdIn:4.2-13.20: X.main[2].d
326         / stdIn:4.2-13.20: X.main[2].a
327         | stdIn:4.2-13.20: X.main[2].b
328    GOTO-\ stdIn:4.2-13.20: X.main[2].c
329    CALL   stdIn:4.2-13.20: X.main[2].g
330    GOTO   stdIn:4.2-13.20: X.main[2].f
331    CALL   stdIn:2.15-17.4: X.main[2]
332    -
333    
334    (Note that because of a FLINt bug the above code currently does not
335    compile without BTrace turned on.)
336    
337    Here is another example, using my modified Tiger compiler:
338    
339    Standard ML of New Jersey v110.28.1 [FLINT v1.5], June 5, 2000
340    - SMLofNJ.Internals.BTrace.mode (SOME true);
341    [autoloading]
342    [autoloading done]
343    val it = false : bool
344    - CM.make "sources.cm";
345    [autoloading]
346    ...
347    [autoloading done]
348    [scanning sources.cm]
349    [parsing (sources.cm):parse.sml]
350    [creating directory CM/SKEL ...]
351    [parsing (sources.cm):tiger.lex.sml]
352    ...
353    [wrote CM/sparc-unix/semant.sml]
354    [compiling (sources.cm):main.sml]
355    [wrote CM/sparc-unix/main.sml]
356    [New bindings added.]
357    val it = true : bool
358    - Main.compile ("../testcases/merge.tig", "foo.out");
359    *** BACK-TRACE ***
360    CALL   lib/semant.sml:99.2-396.21: SemantFun[2].transExp.trvar
361    CALL   lib/semant.sml:99.2-396.21: SemantFun[2].transExp.trexp
362    CALL   lib/semant.sml:289.3-295.22: SemantFun[2].transExp.trexp.check[2]
363    GOTO   lib/semant.sml:289.3-295.22: SemantFun[2].transExp.trexp.check[2]
364    CALL   lib/semant.sml:99.2-396.21: SemantFun[2].transExp.trexp
365    CALL   lib/semant.sml:99.2-396.21: SemantFun[2].transExp.trexp
366    CALL   lib/semant.sml:488.3-505.6: SemantFun[2].transDec.trdec[2].transBody[2]
367         / lib/semant.sml:411.65-543.8: SemantFun[2].transDec
368    CALL-\ lib/semant.sml:413.2-540.9: SemantFun[2].transDec.trdec[2]
369    CALL   lib/semant.sml:99.2-396.21: SemantFun[2].transExp.trexp
370    CALL   lib/semant.sml:8.52-558.4: SemantFun[2].transProg[2]
371    CALL   main.sml:1.18-118.4: Main.compile[2]
372    -
373    
374    ----------------------------------------------------------------------
375    Name: Matthias Blumen
376    Date: 2000/06/21 18:00:00 JST
377    Tag: blume-20000621-manual
378    Description:
379    
380    CM manual update: Path environments documented.
381    
382    ----------------------------------------------------------------------
383    Name: Matthias Blume
384    Date: 2000/06/19 13:40:00
385    Tag: blume-20000619-manual
386    Description:
387    
388    CM manual and system/README update.  This only covers the fact that
389    there are no more implicit anchors.  (Path environments and the "bind"
390    option to "cm" have yet to be documented.)
391    
392    ----------------------------------------------------------------------
393    Name: Matthias Blume
394  Date: 2000/06/19 11:05:00 JST  Date: 2000/06/19 11:05:00 JST
395  Tag: blume-20000619-chdir-bugfix  Tag: blume-20000619-chdir-bugfix
396  Description:  Description:

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