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Added a test checking that the result of [check_partial_all] is unchanged (on the particular example being tested)
We avoid doing some redundant work in the process.
We avoid doing some redundant work in the process.
The other option was to simply use [option].
The tests still pass so I expect that there was indeed no semantic change as a result of this factorization. [1] However I might have have *unreasonably* degraded performances in the simple case. Please have a look. Also, I'd like to rename [satisfiables] to something more meaningful, [list_satisfying_vectors] is only partially convincing, suggestions welcomed. Note: [1]: in my first implementation I had forgotten to guard one of the calls to [set_args] with the [if only_care_about_existence] check. As a result "make world" succeeded, so did the tests typing-warnings/, but "make world.opt" failed with a fatal error in [read_args]. Guarding none of the calls to [set_args] or all of them does fix the problem. I chose to guard all of them, but that might actually have a negative impact on performance in general.
@gasche: you were involved in https://caml.inria.fr/mantis/view.php?id=6437 and might have a better understanding than me of what's going on here. If you're unsure, let's ask Jacques.
The same issue that was reported for typecore.ml in PR#6394 did occur in fragile pattern-matching detection code. Fix is similar: accept the fact that in presence of recursive module some incoherence may happen.
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I had to change base twice to get github to update the PR as expected (looks like they only monitor the pull-from branch...), but it worked. On the other hand, I'm in holidays right now, so don't expect fast reactions :-) |
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As a consequence of the rebase, all the comments are "lost" (i.e. they are on commits not referenced on this PR anymore). Sorry for the email spam this must have generated. |
trefis
reviewed
Jul 25, 2017
| simplify_head_pat r p1 ps varsets (simplify_head_pat r p2 ps varsets k) | ||
| | _ -> | ||
| (p, { row = ps; varsets = r :: varsets; }) :: k | ||
| and simplify_head_pat head_bound_variables p ps varsets k = |
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@gasche said
We could also use
head_variables(of course they are bounds in pattern, I'd say) orhead_varsetif we want something shorter.
To which I answered:
Your choice. I personally don't mind the long name.
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I think this is my fault for commenting before I created the PR. If I comment on the PR now, github should be able to track comments across rebases. |
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This PR has been superseded by ocaml#1488 and ocaml#1560, both merged now. Thanks! |
gasche
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Jul 13, 2024
The toplevel printer detects cycles by keeping a hashtable of values
that it has already traversed.
However, some OCaml runtime types (at least bigarrays) may be
partially uninitialized, and hashing them at arbitrary program points
may read uninitialized memory. In particular, the OCaml testsuite
fails when running with a memory-sanitizer enabled, as bigarray
printing results in reads to uninitialized memory:
```
==133712==WARNING: MemorySanitizer: use-of-uninitialized-value
#0 0x4e6d11 in caml_ba_hash /var/home/edwin/git/ocaml/runtime/bigarray.c:486:45
#1 0x52474a in caml_hash /var/home/edwin/git/ocaml/runtime/hash.c:251:35
#2 0x599ebf in caml_interprete /var/home/edwin/git/ocaml/runtime/interp.c:1065:14
#3 0x5a909a in caml_main /var/home/edwin/git/ocaml/runtime/startup_byt.c:575:9
#4 0x540ccb in main /var/home/edwin/git/ocaml/runtime/main.c:37:3
#5 0x7f0910abb087 in __libc_start_call_main (/lib64/libc.so.6+0x2a087) (BuildId: 8f53abaad945a669f2bdcd25f471d80e077568ef)
#6 0x7f0910abb14a in __libc_start_main@GLIBC_2.2.5 (/lib64/libc.so.6+0x2a14a) (BuildId: 8f53abaad945a669f2bdcd25f471d80e077568ef)
#7 0x441804 in _start (/var/home/edwin/git/ocaml/runtime/ocamlrun+0x441804) (BuildId: 7a60eef57e1c2baf770bc38d10d6c227e60ead37)
Uninitialized value was created by a heap allocation
#0 0x47d306 in malloc (/var/home/edwin/git/ocaml/runtime/ocamlrun+0x47d306) (BuildId: 7a60eef57e1c2baf770bc38d10d6c227e60ead37)
#1 0x4e7960 in caml_ba_alloc /var/home/edwin/git/ocaml/runtime/bigarray.c:246:12
#2 0x4e801f in caml_ba_create /var/home/edwin/git/ocaml/runtime/bigarray.c:673:10
#3 0x59b8fc in caml_interprete /var/home/edwin/git/ocaml/runtime/interp.c:1058:14
#4 0x5a909a in caml_main /var/home/edwin/git/ocaml/runtime/startup_byt.c:575:9
#5 0x540ccb in main /var/home/edwin/git/ocaml/runtime/main.c:37:3
#6 0x7f0910abb087 in __libc_start_call_main (/lib64/libc.so.6+0x2a087) (BuildId: 8f53abaad945a669f2bdcd25f471d80e077568ef)
#7 0x7f0910abb14a in __libc_start_main@GLIBC_2.2.5 (/lib64/libc.so.6+0x2a14a) (BuildId: 8f53abaad945a669f2bdcd25f471d80e077568ef)
#8 0x441804 in _start (/var/home/edwin/git/ocaml/runtime/ocamlrun+0x441804) (BuildId: 7a60eef57e1c2baf770bc38d10d6c227e60ead37)
SUMMARY: MemorySanitizer: use-of-uninitialized-value /var/home/edwin/git/ocaml/runtime/bigarray.c:486:45 in caml_ba_hash
```
The only use of hashing in genprintval is to avoid cycles, that is, it
is only useful for OCaml values that contain other OCaml values
(including possibly themselves). Bigarrays cannot introduce cycles,
and they are always printed as "<abstr>" anyway.
The present commit proposes to be more conservative in which values
are hashed by the cycle detector to avoid this issue: we skip hashing
any value with tag above No_scan_tag -- which may not contain any
OCaml values.
Suggested-by: Gabriel Scherer <[email protected]>
Signed-off-by: Edwin Török <[email protected]>
gasche
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Jul 30, 2024
…l#13294) The toplevel printer detects cycles by keeping a hashtable of values that it has already traversed. However, some OCaml runtime types (at least bigarrays) may be partially uninitialized, and hashing them at arbitrary program points may read uninitialized memory. In particular, the OCaml testsuite fails when running with a memory-sanitizer enabled, as bigarray printing results in reads to uninitialized memory: ``` ==133712==WARNING: MemorySanitizer: use-of-uninitialized-value #0 0x4e6d11 in caml_ba_hash /var/home/edwin/git/ocaml/runtime/bigarray.c:486:45 #1 0x52474a in caml_hash /var/home/edwin/git/ocaml/runtime/hash.c:251:35 #2 0x599ebf in caml_interprete /var/home/edwin/git/ocaml/runtime/interp.c:1065:14 #3 0x5a909a in caml_main /var/home/edwin/git/ocaml/runtime/startup_byt.c:575:9 #4 0x540ccb in main /var/home/edwin/git/ocaml/runtime/main.c:37:3 #5 0x7f0910abb087 in __libc_start_call_main (/lib64/libc.so.6+0x2a087) (BuildId: 8f53abaad945a669f2bdcd25f471d80e077568ef) #6 0x7f0910abb14a in __libc_start_main@GLIBC_2.2.5 (/lib64/libc.so.6+0x2a14a) (BuildId: 8f53abaad945a669f2bdcd25f471d80e077568ef) #7 0x441804 in _start (/var/home/edwin/git/ocaml/runtime/ocamlrun+0x441804) (BuildId: 7a60eef57e1c2baf770bc38d10d6c227e60ead37) Uninitialized value was created by a heap allocation #0 0x47d306 in malloc (/var/home/edwin/git/ocaml/runtime/ocamlrun+0x47d306) (BuildId: 7a60eef57e1c2baf770bc38d10d6c227e60ead37) #1 0x4e7960 in caml_ba_alloc /var/home/edwin/git/ocaml/runtime/bigarray.c:246:12 #2 0x4e801f in caml_ba_create /var/home/edwin/git/ocaml/runtime/bigarray.c:673:10 #3 0x59b8fc in caml_interprete /var/home/edwin/git/ocaml/runtime/interp.c:1058:14 #4 0x5a909a in caml_main /var/home/edwin/git/ocaml/runtime/startup_byt.c:575:9 #5 0x540ccb in main /var/home/edwin/git/ocaml/runtime/main.c:37:3 #6 0x7f0910abb087 in __libc_start_call_main (/lib64/libc.so.6+0x2a087) (BuildId: 8f53abaad945a669f2bdcd25f471d80e077568ef) #7 0x7f0910abb14a in __libc_start_main@GLIBC_2.2.5 (/lib64/libc.so.6+0x2a14a) (BuildId: 8f53abaad945a669f2bdcd25f471d80e077568ef) #8 0x441804 in _start (/var/home/edwin/git/ocaml/runtime/ocamlrun+0x441804) (BuildId: 7a60eef57e1c2baf770bc38d10d6c227e60ead37) SUMMARY: MemorySanitizer: use-of-uninitialized-value /var/home/edwin/git/ocaml/runtime/bigarray.c:486:45 in caml_ba_hash ``` The only use of hashing in genprintval is to avoid cycles, that is, it is only useful for OCaml values that contain other OCaml values (including possibly themselves). Bigarrays cannot introduce cycles, and they are always printed as "<abstr>" anyway. The present commit proposes to be more conservative in which values are hashed by the cycle detector to avoid this issue: we skip hashing any value with tag above No_scan_tag -- which may not contain any OCaml values. Suggested-by: Gabriel Scherer <[email protected]> Signed-off-by: Edwin Török <[email protected]> Co-authored-by: Edwin Török <[email protected]>
gasche
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Sep 23, 2024
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I'm creating this PR to discuss @trefis' efforts to understand and clarify the parmatch code.