2022-08-19 01:55 AEST

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IDProjectCategoryView StatusLast Update
0000559mercuryBugpublic2022-08-03 19:41
Reporterjuliensf 
Assigned Tozs 
PrioritynormalSeverityminorReproducibilityalways
StatusresolvedResolutionfixed 
Product Version 
Target VersionFixed in Version 
Summary0000559: Stack overflow in hlc.gc Mercury 22.01.1 compiler on Windows
DescriptionThe attached module is derived from a stress test for the Zinc compiler. Compiling this with a Mercury 22.0.1 compiler built in the hlc.gc results in a stack overflow on Windows when reading the module. (The significance of Window is that the stack size is very small, even though IIRC we bump it up a bit.)
(This is not a new problem, Mercury 20.01 also has the same problem.)
Steps To Reproduce
    $ mmc -C zm_hug_flat_case.m
TagsNo tags attached.
Attached Files

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-Notes

~0001194

zs (developer)

I believe I have diagnosed the problem, though I cannot confirm it,
since I am not set up to program on Windows.

Compiling zm_huge_flat_case.m with a debug grade compiler under mdb,
the command "min_depth 10000" shows very deep mutual recursion in
parse_goal.m between parse_goal, parse_non_call_goal, and parse_goal_semicolon.
Basically, you need three stack frames for each disjunct in that big
disjunction, and the different determinisms (parse_non_call_goal is semidet,
the others are det) prevent both the MLDS and the LLDS code generator
from being able to do tail recursion.

I have an idea for a solution and will try it out tomorrow, but it may
add some overhead. Once I have an implementation ready, I will need you
to run some benchmarks to see whether it adds any overhead for run-of-the-mill,
non-extreme Mercury code, and if so, whether that overhead is significant.

~0001201

zs (developer)

Last part of the fix committed 2022 may 7.
+Notes

-Issue History
Date Modified Username Field Change
2022-05-03 16:12 juliensf New Issue
2022-05-03 16:12 juliensf File Added: zm_huge_flat_case.m.gz
2022-05-03 18:06 zs Note Added: 0001194
2022-05-03 18:07 zs Assigned To => zs
2022-05-03 18:07 zs Status new => assigned
2022-08-03 19:41 zs Status assigned => resolved
2022-08-03 19:41 zs Resolution open => fixed
2022-08-03 19:41 zs Note Added: 0001201
+Issue History