Linux: can we compile with -DLLVM_ENABLE_ASSERTIONS=ON

[nickdesaulniers]

clang releases are typically produced with the cmake option -DCMAKE_BUILD_TYPE=Release because debug builds are too slow. -DLLVM_ENABLE_ASSERTIONS=ON is a happy medium; a release optimized build but with LLVM_ASSERTs kept on. We should see if we fail any assertions for some allyesoonfig builds.

[nathanchance]

I’ll see if I can allocate some time tonight/tomorrow to see what kind of time impact we are looking at here. Doesn’t Chromium do this? I thought there was some discussion about whether to turn this off because of the performance impact.

[nathanchance]

Ah, I thought this was in the tc-build repo, whoops. I will still take a look at time stats just in case this is something we would want to turn on there (as well as seeing if it is feasible).

[nathanchance]

arm little endian allyesconfig shows some assertion failures (build log)

I am going to apply the following LLVM patches to see if anything changes:

• https://reviews.llvm.org/D62555
• https://reviews.llvm.org/D64167
• https://reviews.llvm.org/D64368

[nathanchance]

Looks like with all of those patches, the following builds pass with assertions enabled:

• arm little endian allyesconfig
• arm64 little endian allyesconfig
• ppc32 ppc44x_defconfig
• ppc64le powernv_defconfig
• x86_64 allyesconfig

Times:

• Without assertions: 42m 16s
• With assertions: 49m 48s

[nickdesaulniers]

That's great to hear, thanks too for the stats!