Stack overflow in SimCodeUtil.createAllDiffedSimVars

[Francesco Casella]

I have a large model with 200.000 equations that gives stack overflow with the standard Linux stack size of 8 MB. The problem is solved by increasing it to 65 MB or more.

[/build/openmodelica-qI4Plt/openmodelica-1.13.0~dev-86-g73d3087/OMCompiler/Compiler/SimCode/SimCodeMain.mo:440:3-440:155:writable] Error: Internal error Stack overflow in SimCodeMain.generateModelCode...
[bt] #1 /usr/bin/../lib/x86_64-linux-gnu/omc/libOpenModelicaRuntimeC.so(mmc_setStacktraceMessages_threadData)
[bt] #2 /usr/bin/../lib/x86_64-linux-gnu/omc/libOpenModelicaCompiler.so(Expression.isZero)
[bt] #3 /usr/bin/../lib/x86_64-linux-gnu/omc/libOpenModelicaCompiler.so(ExpressionSimplify.simplifyBinaryCommutativeWork)
[bt] #4 /usr/bin/../lib/x86_64-linux-gnu/omc/libOpenModelicaCompiler.so(ExpressionSimplify.simplifyBinaryCommutative)
[bt] #5 /usr/bin/../lib/x86_64-linux-gnu/omc/libOpenModelicaCompiler.so(ExpressionSimplify.simplifyBinary2)
[bt] #6 /usr/bin/../lib/x86_64-linux-gnu/omc/libOpenModelicaCompiler.so(ExpressionSimplify.simplifyBinary)
[bt] #7 /usr/bin/../lib/x86_64-linux-gnu/omc/libOpenModelicaCompiler.so(ExpressionSimplify.simplifyWork)
[bt] #8...9 /usr/bin/../lib/x86_64-linux-gnu/omc/libOpenModelicaCompiler.so(Expression.traverseExpBottomUp)
[bt] #10 /usr/bin/../lib/x86_64-linux-gnu/omc/libOpenModelicaCompiler.so(ExpressionSimplify.simplify1FixP)
[bt] #11 /usr/bin/../lib/x86_64-linux-gnu/omc/libOpenModelicaCompiler.so(ExpressionSimplify.simplify1WithOptions)
[bt] #12 /usr/bin/../lib/x86_64-linux-gnu/omc/libOpenModelicaCompiler.so(ExpressionSimplify.simplify1)
[bt] #13 /usr/bin/../lib/x86_64-linux-gnu/omc/libOpenModelicaCompiler.so(Expression.createResidualExp2)
[bt] #14 /usr/bin/../lib/x86_64-linux-gnu/omc/libOpenModelicaCompiler.so(Expression.createResidualExp)
[bt] #15...1024 /usr/bin/../lib/x86_64-linux-gnu/omc/libOpenModelicaCompiler.so(SimCodeUtil.createNonlinearResidualEquations)
[bt] #1025 [...]

I can provide the test case, which is not public, for debugging, but maybe you can catch and remove the bad recursion just based on the stack trace.

[Henning Kiel]

I implemented a fix that avoids recursion in ​OMCompiler#1838
@casella please test

[Francesco Casella]

SimCodeUtil.createNonlinearResidualEquations is now fine, but the stack now overflows on another function (I guess there are many...)

[bt] #1 /usr/bin/../lib/x86_64-linux-gnu/omc/libOpenModelicaRuntimeC.so(mmc_setStacktraceMessages_threadData)
[bt] #2 /usr/bin/../lib/x86_64-linux-gnu/omc/libOpenModelicaCompiler.so(List.fill)
[bt] #3 /usr/bin/../lib/x86_64-linux-gnu/omc/libOpenModelicaCompiler.so(ComponentReference.hashSubscripts)
[bt] #4 /usr/bin/../lib/x86_64-linux-gnu/omc/libOpenModelicaCompiler.so(ComponentReference.hashComponentRef)
[bt] #5 /usr/bin/../lib/x86_64-linux-gnu/omc/libOpenModelicaCompiler.so(ComponentReference.hashComponentRefMod)
[bt] #6 /usr/bin/../lib/x86_64-linux-gnu/omc/libOpenModelicaCompiler.so(BackendVariable.getVar2)
[bt] #7 /usr/bin/../lib/x86_64-linux-gnu/omc/libOpenModelicaCompiler.so(BackendVariable.getVarSingle)
[bt] #8...1024 /usr/bin/../lib/x86_64-linux-gnu/omc/libOpenModelicaCompiler.so(SimCodeUtil.createAllDiffedSimVars)
[bt] #1025 [...]", "TRANSLATION", "Error", "63"}

[Henning Kiel]

I implemented a fix that avoids recursion in ​OMCompiler#1844
@casella please test

[Francesco Casella]

No more stack overflows with this test, even if I reduce the stack size from 8192 to 4000 kB.

Thanks @hkiel!