Move LIBCXX_DEBUG flag from Travis to AWS codebuild

[smowton]

The Travis build takes too long to complete with this flag set; moving it to AWS CodeBuild
means we can take advantage of AWS' longer timeout and even the load between Travis and AWS.

[hannes-steffenhagen-diffblue]

LGTM

[allredj]

✔️
Passed Diffblue compatibility checks (cbmc commit: f734176).
Build URL: https://travis-ci.com/diffblue/test-gen/builds/113611993

[tautschnig]

Note that you are completely replacing CXXFLAGS at this point - you might actually want CXXFLAGS="-Wall -pedantic -Werror -Wno-deprecated-declarations -Wswitch-enum -D_GLIBCXX_DEBUG"

[tautschnig]

Note that EXTRA_CXXFLAGS also applied to the unit and regression tests in our Travis config. You are not currently doing so for the buildspec. That might actually be the explanation of the error, given the particular tests that are failing.

[smowton]

You're right, the cause was compiling the little driver program provided by the invariants regression tests without -D_GLIBCXX_DEBUG, meaning that it created std::vectors which were then reinterpreted as std::__debug::vectors by libutil code, which had been compiled with the flag.

[smowton]

@tautschnig pushed an alternative solution introducing CP_EXTRA_CXXFLAGS (and _CFLAGS), so it's easy to specify an addition to rather than a replacement for the default flags.

[tautschnig]

@smowton @xbauch Could you jointly debug the failure that's now showing up? EXIT=134 is likely an internal invariant failing, but I guess chain.sh eats up the output so it's not immediately visible in the CI log.

[smowton]

@tautschnig turns out the offending code (which did indeed call std::string::back on an empty string) had been deleted upstream in the meantime, so rebased and repushed.

[tautschnig]

@smowton It seems this needs another rebase as clang-format was confused.

[allredj]

✔️
Passed Diffblue compatibility checks (cbmc commit: 44458f6).
Build URL: https://travis-ci.com/diffblue/test-gen/builds/113765649