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Merged
merged 2 commits into from
Feb 4, 2020
Merged

Stop generating nondet pointees for function pointers #4940

merged 2 commits into from
Feb 4, 2020

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xbauch
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@xbauch xbauch commented Jul 23, 2019

when building the entry point. Because that leads to declaring function-type
objects and then assigning values to them. Rather we should simply initialise
the function pointer with NONDET(fptr_type) and let the function-pointer removal
find the candidates.

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allredj
allredj reviewed Jul 23, 2019
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✔️
Passed Diffblue compatibility checks (cbmc commit: e5d5c9f).
Build URL: https://travis-ci.com/diffblue/test-gen/builds/120202139

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codecov-io commented Jul 23, 2019 •
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Codecov Report

Merging #4940 into develop will not change coverage.
The diff coverage is 100%.

Impacted file tree graph

@@           Coverage Diff            @@
##           develop    #4940   +/-   ##
========================================
  Coverage    67.38%   67.38%           
========================================
  Files         1157     1157           
  Lines        95096    95096           
========================================
  Hits         64080    64080           
  Misses       31016    31016
Flag Coverage Δ
#cproversmt2 42.66% <100%> (ø) ⬆️
#regression 63.89% <100%> (ø) ⬆️
#unit 31.92% <0%> (ø) ⬆️
Impacted Files Coverage Δ
src/ansi-c/c_nondet_symbol_factory.cpp 100% <100%> (ø) ⬆️

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@xbauch xbauch mentioned this pull request Jan 3, 2020
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@xbauch xbauch force-pushed the fix/function-pointer-init branch 2 times, most recently from a0308a5 to 68c9554 Compare January 17, 2020 14:49
allredj
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✔️
Passed Diffblue compatibility checks (cbmc commit: 68c9554).
Build URL: https://travis-ci.com/diffblue/test-gen/builds/144957668

hannes-steffenhagen-diffblue
hannes-steffenhagen-diffblue approved these changes Jan 24, 2020
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This comes up a lot, maybe we should have a utility function like is_pointer_to_object or something of the sort?

thk123
thk123 reviewed Jan 29, 2020
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🚫 Please add a test for when there is a function of the right type, to check it is selected. And two functions of the right type, to check it picks between them (as I believe the new behaviour should / old behaviour did not).

src/ansi-c/c_nondet_symbol_factory.cpp Outdated
@@ -48,7 +48,7 @@ void symbol_factoryt::gen_nondet_init(
return;
}

if(type.id()==ID_pointer)
if(type.id() == ID_pointer && to_pointer_type(type).subtype().id() != ID_code)
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❓ What happens with pointers to code then? Just random number?
Read the PR description - that is worth a comment here explaining why we don't need to initialize it here

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Now the symbol is explicitly assigned a nondet (of the function-ptr type).

@xbauch xbauch force-pushed the fix/function-pointer-init branch from 68c9554 to 9ea6857 Compare January 29, 2020 13:16
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xbauch commented Jan 29, 2020

Please add a test for when there is a function of the right type, to check it is selected. And two functions of the right type, to check it picks between them (as I believe the new behaviour should / old behaviour did not).

I've added the tests. Note that existing functions will only be considered as candidates if dereferenced somewhere in the code.

@petr-bauch
Stop generating nondet pointees for function pointers
1299a54 
when building the entry point. Because that leads to declaring function-type
objects and then assigning values to them. Rather we should simply initialise
the function pointer with NONDET(fptr_type) and let the function-pointer removal
find the candidates.
@xbauch xbauch force-pushed the fix/function-pointer-init branch from 9ea6857 to 1299a54 Compare January 29, 2020 13:22
thk123
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LGTM, thanks for the extra tests.
This just needs code owner approval @tautschnig @kroening

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thk123 commented Jan 29, 2020

currently failing CI, but looks transient, have restarted the job

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thk123 commented Jan 30, 2020

This is now passing CI and just needs code owner approval @tautschnig @kroening

@tautschnig tautschnig merged commit cccdfd9 into diffblue:develop Feb 4, 2020
@tautschnig tautschnig mentioned this pull request Feb 4, 2020
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@thk123 thk123 thk123 approved these changes

@tautschnig tautschnig tautschnig approved these changes

@hannes-steffenhagen-diffblue hannes-steffenhagen-diffblue hannes-steffenhagen-diffblue approved these changes

@kroening kroening Awaiting requested review from kroening kroening is a code owner

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@xbauch @codecov-io @thk123 @tautschnig @allredj @hannes-steffenhagen-diffblue @kroening @petr-bauch