Failing test suite with 0.4.0 release on MacOS

[cubranic]

WIth Zig 0.4.0 built from source on macOS 10.14.4 (Mojave), I get the following error when running bin/zig build --build-file ../build.zig test -Dskip-release:

Assertion failed: ((uint64_t)loc % alignof(T) == 0 && "invalid pointer alignment"), function read64, file /Users/davor/projects/ziggly/zig/deps/lld/lib/ReaderWriter/MachO/MachONormalizedFileBinaryUtils.h, line 86.
The following command terminated unexpectedly:
/Users/davor/projects/ziggly/zig/build/bin/zig test /Users/davor/projects/ziggly/zig/test/standalone/static_c_lib/foo.zig --object /Users/davor/projects/ziggly/zig/test/standalone/static_c_lib/zig-cache/o/SUe_YiPh1_Ew6fiegQeR8ME86r6PNe-adxCtuWf8bVaQx3w_6ftZmy4uax5-vaqd/libfoo.a --cache-dir /Users/davor/projects/ziggly/zig/test/standalone/static_c_lib/zig-cache --name test -isystem /Users/davor/projects/ziggly/zig/test/standalone/static_c_lib/zig-cache/o/SUe_YiPh1_Ew6fiegQeR8ME86r6PNe-adxCtuWf8bVaQx3w_6ftZmy4uax5-vaqd -isystem /Users/davor/projects/ziggly/zig/test/standalone/static_c_lib

Is this a known failure, or a possible problem with my setup? There are 5,718 passing tests (counted by their printing "...OK").

[mikdusan]

I have been getting this same failure on macOS 10.11, 10.13 and 10.14 against different versions of Xcode but haven't really investigated.

[andrewrk]

Does the problem occur with master branch?

[mikdusan]

Does the problem occur with master branch?

yes. In fact I cannot recall ever having success runing full test on macOS. On linux, yes, I get good result. Off hand I'm thinking why does it work with CI builds? Primary diff is CI uses gcc8 to build zig's LLVM toolchain, I'm using Xcode-clang. If memory serves custom-clang also gave me same failure.

[andrewrk]

Hmm. Unfortunately it works on my fully updated 10.14.4 macOS laptop as well so I cannot reproduce the issue. I need some help figuring out what's different about our systems. I build with Homebrew and the default system compiler.

[andrewrk]

I will note the assertion is in LLD, the linker, which is known to be problematic for the macOS target and one of the reasons for #1535.

[cubranic]

Yes:

Assertion failed: ((uint64_t)loc % alignof(T) == 0 && "invalid pointer alignment"), function read64, file /Users/davor/projects/ziggly/zig/deps/lld/lib/ReaderWriter/MachO/MachONormalizedFileBinaryUtils.h, line 86.
The following command terminated unexpectedly:
/Users/davor/projects/ziggly/zig/build/bin/zig test /Users/davor/projects/ziggly/zig/test/standalone/static_c_lib/foo.zig --object /Users/davor/projects/ziggly/zig/test/standalone/static_c_lib/zig-cache/o/o5L8eEhBLQTVzmg8zEVN20-UmhYp5v753OP30PuJ2DNoJ9yIggEtSdicH4O2EYIN/libfoo.a --cache-dir /Users/davor/projects/ziggly/zig/test/standalone/static_c_lib/zig-cache --name test -isystem /Users/davor/projects/ziggly/zig/test/standalone/static_c_lib/zig-cache/o/o5L8eEhBLQTVzmg8zEVN20-UmhYp5v753OP30PuJ2DNoJ9yIggEtSdicH4O2EYIN -isystem /Users/davor/projects/ziggly/zig/test/standalone/static_c_lib

Build failed. The following command failed:
/Users/davor/projects/ziggly/zig/test/standalone/static_c_lib/zig-cache/o/gNZfNp5X8svdTkLz5e_tsmhdpqIG8PGIYsH7YPBHRb-djo-7VcgWzzatSmaieC2F/build /Users/davor/projects/ziggly/zig/build/bin/zig /Users/davor/projects/ziggly/zig/test/standalone/static_c_lib /Users/davor/projects/ziggly/zig/test/standalone/static_c_lib/zig-cache test
The following command exited with error code 1:
cd /Users/davor/projects/ziggly/zig && build/bin/zig build --build-file /Users/davor/projects/ziggly/zig/test/standalone/static_c_lib/build.zig test

Build failed. The following command failed:
/Users/davor/projects/ziggly/zig/zig-cache/o/XyKkE9WQu-rXGS9zS1-Rxpx3rC3ZOSwTSFWPWsbXSa31LnQ4upnkBLxBR6YPg2EW/build /Users/davor/projects/ziggly/zig/build/bin/zig /Users/davor/projects/ziggly/zig /Users/davor/projects/ziggly/zig/zig-cache test -Dskip-release

[mikdusan]

ok I've reduced it down to how Zig is built but have yet to find out why -DCMAKE_BUILD_TYPE=Release is a factor.

TEST FAILURE

cmake -G Ninja /Users/mike/project/zig/master -DCMAKE_INSTALL_PREFIX=/opt/zig -DCMAKE_PREFIX_PATH=/opt/llvm-8.0.0

TEST SUCCESS

cmake -G Ninja /Users/mike/project/zig/master -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/opt/zig -DCMAKE_PREFIX_PATH=/opt/llvm-8.0.0

[cubranic]

@andrewrk it sounds like our setups are very similar. Same OS version, and I also build with Homebrew. I used the exact directions from the README:

• Homebrew llvm@8
• cmake with -DCMAKE_PREFIX_PATH=/usr/local/Cellar/llvm/8.0.0

I'd be happy to dig in deeper to find differences between our two configurations.

[andrewrk]

@mikdusan I can explain that one: -DCMAKE_BUILD_TYPE=Release disables asserts. This issue is about an assertion failure. The LLD code probably ends up working fine in practice even though it tripped an assertion failure.

[mikdusan]

This looks to be a bug in lld. What's happening is the .a is loaded into MemoryBuffer and the managed buffer is not aligned. Then the usual pointer casting into mach_header which is offset-zero in the buffer. And the first field magic is 32-bit and lld code asserts with generic read functions this must be 4-byte aligned.