bugGNU Octave - Bugs: bug #65304, bytecode compiler fails with VM...

 
 

bug #65304: bytecode compiler fails with VM error 5274

Submitter:  A.R. Burgers <arb>
Submitted:  Tue 13 Feb 2024 03:26:11 PM UTC
   
 
Category:  Interpreter Severity:  3 - Normal
Priority:  5 - Normal Item Group:  Unexpected Error or Warning
Status:  Patch Submitted Assigned to:  None
Originator Name:  Open/Closed:  * Open
Release:  * bytecode-evaluator Operating System:  * GNU/Linux
Fixed Release:  None Planned Release:  None
* Mandatory Fields

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Fri 05 Apr 2024 06:36:50 PM UTC, comment #4: 

I noted those, too.

FWIW, I regularly make Linux builds and Windows (cross-)builds and AFAIK I have all of Petter's patches included + one by "Fernando" (bug #64783). I see no bytecode-interpreter related (or suspected) failures running the test suite on Linux and Windows.

That said, ATM I don't use Octave very much at work (that might change in the next weeks) so I guess due to that I don't hit problems other than cosmetic ones.

Philip Nienhuis <philipnienhuis>
Group Member
Fri 05 Apr 2024 02:45:31 AM UTC, comment #3: 

octave_33191.patch needs to be refreshed: "Hunk #12 FAILED at 6433.". This refresh is required due to the commit from Tue Mar 26: Change "assert" to "panic_unless".


-    assert (N_RETURNS () == -128);
+    assert (N_RETURNS () == -32768);


should be refreshed to


-    panic_unless (N_RETURNS () == -128);
+    panic_unless (N_RETURNS () == -32768);



Note:
The state of the bytecode compiler branch degrades creating additional effort and reducing usability for the broader community:

A number of (rather serious) bytecode compiler bugs are still in the pipeline with a patch provided since quite a while by Petter (some since more than 6 weeks), but not yet reviewed and migrated.
See also https://octave.discourse.group/t/wip-stack-vm-for-octave/2884/186.



Hendrik K <koerhen>
Wed 14 Feb 2024 10:59:27 PM UTC, comment #2: 

Here are two patches that should solve the issue.

The first patch allows for more than 255 arguments, up to 2^16-1 in an index operation.

The other patch allows for more than 255, up to 2^15-1, named arguments or return symbols when compiling a function.


Allow more than 255 arguments to index operations in bytecode (bug #65304)

Change some opcodes to use 2 bytes for number of args and use them when
the number of args is bigger than 255. INDEX_STRUCT_SUBCALL, INDEX_STRUCT_CALL,
WORDCMD, WORDCMD_NX and INDEX_OBJ.

* pt-bytecode-vm.cc: Use two bytes for number of args for the opcodes
* pt-bytecode-walk.cc: Use the opcodes when many args


Support more than 255 named arguments and returns in the bytecode interpreter (bug #65304)

Use two bytes to store the amount of argument symbols and return symbols, to allow
for 2^15-1 symbols. Replace magic anon. fn. marker -128 with -32768.

* pt-bytecode-vm-internal.h: Change size to two bytes
* pt-bytecode-vm.cc: Change size to two bytes
* pt-bytecode-walk.cc: Emit two bytes
                       Error check new limits
* bytecode_subfuncs.m: Update tests


(file #55703, file #55704)

Petter <petter>
Tue 13 Feb 2024 10:49:53 PM UTC, comment #1: 

Thanks for the report. You hit the 255 argument limit for index operations. I guess that it should be quite common to want to do that for those kind of constellations, so the limit is probably too low.

I've made a patch that would support up to 2^16-1 arguments. I'll attach a wip version that you could try, but I think there might be other opcodes that need "many args" support, so I'll clean it up and see if I can find more places that could be an issue. At least chained index operations e.g. "struct ( .. many args .. ).qwe;" would need it too.

(file #55692)

Petter <petter>
Tue 13 Feb 2024 03:26:11 PM UTC, original submission:  

The attached function fails to compile with VM error 5274.

sample code:


version -hgid
VM_fail;


gives this output and error:


octave:8> version -hgid
ans = 19973af3ac42
octave:9> VM_fail;
warning: auto-compilation of VM_fail failed with message VM error 5274: internal VM compiler consistency check failed, code_check_s_ < 256 && code_check_s_ >= -128


A.R. Burgers <arb>

 

(Note: upload size limit is set to 16384 kB, after insertion of the required escape characters.)

Attach Files:
   
   
Comment:
   

Attached Files
file #55703:  octave_33190.patch added by petter (7KiB - text/plain)
file #55704:  octave_33191.patch added by petter (17KiB - text/plain)
file #55692:  33183.patch added by petter (4KiB - text/plain)
file #55690:  VM_fail.m added by arb (35KiB - text/plain)

 

Depends on the following items: None found

Items that depend on this one: None found

 

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    Follow 5 latest changes.

    Date Changed by Updated Field Previous Value => Replaced by
    2024-02-21 philipnienhuis StatusNone Patch Submitted
    2024-02-14 petter Attached File- Added octave_33190.patch, #55703
        Attached File- Added octave_33191.patch, #55704
    2024-02-13 petter Attached File- Added 33183.patch, #55692
    2024-02-13 arb Attached File- Added VM_fail.m, #55690

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