Run MIR-libstd tests for other architectures

[RalfJung]

Currently, Travis runs MIR-libstd tests only for the host architecture. Ideally, this should also be done for other architectures.

[oli-obk]

I think this is blocked on rust-lang/rust#36501, because we can't build apple/windows jemalloc on linux

[RalfJung]

Right so we want to build libstd with the system allocator, so the only code that has to be cross-compiled is Rust code.
xargo says that needs something like rust-lang/rust#37975.

[oli-obk]

If rust-lang/rust#43628 goes through in its current form, we'd be all set, no more need for xargo

[RalfJung]

However, I will soon want for miri to be tested against a libstd that also uses -Zmir-emit-validate=1, so this wouldn't really help.

[oli-obk]

We can use lld as the linker and we inject our own jemalloc crate which doesn't do anything.

[oli-obk]

Or we use features = ["force_alloc_system"] in xargo.toml.

[RalfJung]

Or we use features = ["force_alloc_system"] in xargo.toml.

According to xargo README, that doesn't actually work, exactly due to lack of rust-lang/rust#37975. I did not investigate this further yet.

[RalfJung]

Hm, I suppose force_alloc_system is newer. However, just setting that in Xargo does not work:

    Updating registry `https://github.com/rust-lang/crates.io-index`
   Compiling gcc v0.3.51
   Compiling libc v0.2.29
   Compiling core v0.0.0 (file:///home/r/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/libcore)
   Compiling libc v0.0.0 (file:///home/r/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/rustc/libc_shim)
   Compiling unwind v0.0.0 (file:///home/r/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/libunwind)
   Compiling filetime v0.1.10
   Compiling build_helper v0.1.0 (file:///home/r/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/build_helper)
   Compiling compiler_builtins v0.0.0 (file:///home/r/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/rustc/compiler_builtins_shim)
   Compiling std v0.0.0 (file:///home/r/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/libstd)
   Compiling cmake v0.1.24
   Compiling rustc_lsan v0.0.0 (file:///home/r/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/librustc_lsan)
   Compiling rustc_asan v0.0.0 (file:///home/r/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/librustc_asan)
   Compiling rustc_msan v0.0.0 (file:///home/r/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/librustc_msan)
   Compiling rustc_tsan v0.0.0 (file:///home/r/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/librustc_tsan)
   Compiling std_unicode v0.0.0 (file:///home/r/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/libstd_unicode)
   Compiling rand v0.0.0 (file:///home/r/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/librand)
   Compiling panic_abort v0.0.0 (file:///home/r/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/libpanic_abort)
   Compiling alloc v0.0.0 (file:///home/r/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/liballoc)
   Compiling panic_unwind v0.0.0 (file:///home/r/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/libpanic_unwind)
   Compiling alloc_system v0.0.0 (file:///home/r/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/liballoc_system)
   Compiling collections v0.0.0 (file:///home/r/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/src/libcollections)
error[E0463]: can't find crate for `alloc_jemalloc`

error: aborting due to previous error

error: Could not compile `std`.

[RalfJung]

I reported this as rust-lang/rust#43637. I feel like something fishy is going on...

[RalfJung]

The good news is that I locally managed to cross-compile libstd without having a C toolchain for the target! The bad news is that I have no idea how to make that work with the upstream rust-src component... here's what I did:

• Compile rustc stage1 locally (currently you have to also apply use gcc::Build rather than deprecated gcc::Config rust#43975 to not fail later).
• Make that stage1 the toolchain we use.
• Patch the rustc source folder: In $RUSTDIR/src/rustc/compiler_builtins_shim/Cargo.toml, remove "c" from the default features. In $RUSTDIR/src/libstd/Cargo.toml, remove "dylib" from the crate types.
• In miri's source, cd xargo. Edit Xargo.toml to remove the "jemalloc" feature. (You can remove "panic_unwind" as well, it doesn't make a difference.)
• XARGO_RUST_SRC=$RUSTDIR/src/ RUSTFLAGS='-Zalways-encode-mir -Zmir-emit-validate=1' xargo build --target i686-unknown-linux-gnu should succeed now!

Unfortunately, it seems cross-compiling a dylib does need a C toolchain for the target, which is why I had to not build libstd as a dylib. It also doesn't seem to be possible to change the crate type depending on features (though maybe build scripts can do something here?), which means there currently is no way to upstream this.

libstd being a dylib really is a huge pain. :/ The dylib build fails with

     Running `rustc --crate-name std /home/r/src/rust/rustc.2/src/libstd/lib.rs --crate-type dylib --crate-type rlib --emit=dep-info,link -C prefer-dynamic -C opt-level=3 --cfg 'feature="force_alloc_system"' --cfg 'feature="panic_unwind"' -C metadata=6425f2b7e4e24bbc --out-dir /tmp/xargo.Ux1FcrLpYOVz/target/i686-unknown-linux-gnu/release/deps --target i686-unknown-linux-gnu -L dependency=/tmp/xargo.Ux1FcrLpYOVz/target/i686-unknown-linux-gnu/release/deps -L dependency=/tmp/xargo.Ux1FcrLpYOVz/target/release/deps --extern panic_abort=/tmp/xargo.Ux1FcrLpYOVz/target/i686-unknown-linux-gnu/release/deps/libpanic_abort-aca288d1876270cd.rlib --extern compiler_builtins=/tmp/xargo.Ux1FcrLpYOVz/target/i686-unknown-linux-gnu/release/deps/libcompiler_builtins-8121025650d9f1cf.rlib --extern alloc_system=/tmp/xargo.Ux1FcrLpYOVz/target/i686-unknown-linux-gnu/release/deps/liballoc_system-0182c16197ecc71c.rlib --extern libc=/tmp/xargo.Ux1FcrLpYOVz/target/i686-unknown-linux-gnu/release/deps/liblibc-38f9b1efe225e386.rlib --extern alloc=/tmp/xargo.Ux1FcrLpYOVz/target/i686-unknown-linux-gnu/release/deps/liballoc-25e0045b24994582.rlib --extern std_unicode=/tmp/xargo.Ux1FcrLpYOVz/target/i686-unknown-linux-gnu/release/deps/libstd_unicode-8d9513943e1c6875.rlib --extern core=/tmp/xargo.Ux1FcrLpYOVz/target/i686-unknown-linux-gnu/release/deps/libcore-b085860ac99f8331.rlib --extern collections=/tmp/xargo.Ux1FcrLpYOVz/target/i686-unknown-linux-gnu/release/deps/libcollections-b1e405eb98a3aeaf.rlib --extern rand=/tmp/xargo.Ux1FcrLpYOVz/target/i686-unknown-linux-gnu/release/deps/librand-d5ae1183151f520b.rlib --extern unwind=/tmp/xargo.Ux1FcrLpYOVz/target/i686-unknown-linux-gnu/release/deps/libunwind-b966fbb31ba936d3.rlib --extern panic_unwind=/tmp/xargo.Ux1FcrLpYOVz/target/i686-unknown-linux-gnu/release/deps/libpanic_unwind-2820ee3cab700d09.rlib -Zalways-encode-mir -Zmir-emit-validate=1 --sysroot /home/r/.xargo -Z force-unstable-if-unmarked -l dl -l rt -l pthread`
error: linking with `cc` failed: exit code: 1
  |
  = note: "cc" "-Wl,--as-needed" "-Wl,-z,noexecstack" "-m32" "-L" "/home/r/.xargo/lib/rustlib/i686-unknown-linux-gnu/lib" "/tmp/xargo.Ux1FcrLpYOVz/target/i686-unknown-linux-gnu/release/deps/std.0.o" "-o" "/tmp/xargo.Ux1FcrLpYOVz/target/i686-unknown-linux-gnu/release/deps/libstd.so" "/tmp/xargo.Ux1FcrLpYOVz/target/i686-unknown-linux-gnu/release/deps/std.crate.metadata.o" "/tmp/xargo.Ux1FcrLpYOVz/target/i686-unknown-linux-gnu/release/deps/std.crate.allocator.o" "-Wl,-z,relro,-z,now" "-Wl,-O1" "-nodefaultlibs" "-L" "/tmp/xargo.Ux1FcrLpYOVz/target/i686-unknown-linux-gnu/release/deps" "-L" "/tmp/xargo.Ux1FcrLpYOVz/target/release/deps" "-L" "/home/r/.xargo/lib/rustlib/i686-unknown-linux-gnu/lib" "-l" "dl" "-l" "rt" "-l" "pthread" "-Wl,-Bstatic" "-Wl,--whole-archive" "/tmp/rustc.QgAxzSnrdFRC/libpanic_unwind-2820ee3cab700d09.rlib" "-Wl,--no-whole-archive" "-Wl,--whole-archive" "/tmp/rustc.QgAxzSnrdFRC/libunwind-b966fbb31ba936d3.rlib" "-Wl,--no-whole-archive" "-Wl,--whole-archive" "/tmp/rustc.QgAxzSnrdFRC/librand-d5ae1183151f520b.rlib" "-Wl,--no-whole-archive" "-Wl,--whole-archive" "/tmp/rustc.QgAxzSnrdFRC/liballoc_system-0182c16197ecc71c.rlib" "-Wl,--no-whole-archive" "-Wl,--whole-archive" "/tmp/rustc.QgAxzSnrdFRC/liblibc-38f9b1efe225e386.rlib" "-Wl,--no-whole-archive" "-Wl,--whole-archive" "/tmp/rustc.QgAxzSnrdFRC/liballoc-25e0045b24994582.rlib" "-Wl,--no-whole-archive" "-Wl,--whole-archive" "/tmp/rustc.QgAxzSnrdFRC/libstd_unicode-8d9513943e1c6875.rlib" "-Wl,--no-whole-archive" "-Wl,--whole-archive" "/tmp/rustc.QgAxzSnrdFRC/libcore-b085860ac99f8331.rlib" "-Wl,--no-whole-archive" "/tmp/rustc.QgAxzSnrdFRC/libcompiler_builtins-8121025650d9f1cf.rlib" "-Wl,-Bdynamic" "-l" "gcc_s" "-l" "c" "-l" "m" "-l" "rt" "-l" "pthread" "-l" "util" "-shared"
  = note: /usr/bin/ld: cannot find crti.o: No such file or directory
          /usr/bin/ld: cannot find -ldl
          /usr/bin/ld: cannot find -lrt
          /usr/bin/ld: cannot find -lpthread
          /usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/6/libgcc.a when searching for -lgcc
          /usr/bin/ld: cannot find -lgcc
          collect2: error: ld returned 1 exit status

[RalfJung]

miri still doesn't run unpatched test cases after this:

$ MIRI_SYSROOT=~/.xargo/ cargo run --bin miri -- --target i686-unknown-linux-gnu tests/run-pass-fullmir/heap.rs 
    Finished dev [unoptimized + debuginfo] target(s) in 0.0 secs
     Running `target/debug/miri --target i686-unknown-linux-gnu tests/run-pass-fullmir/heap.rs`
error[E0463]: can't find crate for `alloc_jemalloc`

error: aborting due to previous error

This is fixed by adding the following to the test source:

#![feature(alloc_system, allocator_api, global_allocator)]
extern crate alloc_system;
#[global_allocator]
static ALLOC: alloc_system::System = alloc_system::System;

This still fails, but that's because the allocator API emulation in fn_call.rs is too tied to particular symbol names.

I don't think there is a way to set the default allocator from outside the source... so even if we managed to get the right libstd, we'd still have to add this silly prelude to every single test.

[oli-obk]

I don't think there is a way to set the default allocator from outside the source... so even if we managed to get the right libstd, we'd still have to add this silly prelude to every single test.

miri can insert that prelude to all compilations

[oli-obk]

in the short term we can just add an additional travis matrix for 32 bit

Appveyor already has bot 64 and 32 bit

Macs are blocked on me not having a mac and no mac users being interested enough in miri to get it working with full mir