`Invalid bitcast` error when building rustc (rustc-std-workspace-core)

[bryangarza]

Description

I'm building rustc on an Amazon Linux 2 (m5.24xlarge) machine. This has worked for me the last 5 months, but currently, HEAD is giving me an error when running ./x.py build library.

I thought that it was maybe something I had caused, so I spun up a brand new instance, but I'm still able to reproduce.

Meta

uname -a:

Linux <redacted> <redacted>.amzn2int.x86_64 #1 SMP Sat Mar 11 23:51:58 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux

rust HEAD

7908a1d65496b88626e4b7c193c81d777005d6f3

Error output

Assembling stage1 compiler
Building stage1 library artifacts (x86_64-unknown-linux-gnu)
   Compiling compiler_builtins v0.1.91
   Compiling core v0.0.0 (/local/home/garzbrya/projects/rustc/issue-110467-safe-transmute2/library/core)
   Compiling libc v0.2.140
   Compiling cc v1.0.77
   Compiling memchr v2.5.0
   Compiling std v0.0.0 (/local/home/garzbrya/projects/rustc/issue-110467-safe-transmute2/library/std)
   Compiling unwind v0.0.0 (/local/home/garzbrya/projects/rustc/issue-110467-safe-transmute2/library/unwind)
   Compiling rustc-std-workspace-core v1.99.0 (/local/home/garzbrya/projects/rustc/issue-110467-safe-transmute2/library/rustc-std-workspace-core)
Invalid bitcast
ptr bitcast (ptr addrspace(14979816) @anon.0dd304449d08a524feadd4cd33e8bcb6.1 to ptr)
LLVM ERROR: Broken module found, compilation aborted!
error: could not compile `core`
warning: build failed, waiting for other jobs to finish...
huge alignment values are unsupported
  %15 = load i64, ptr %9, align 70368744177664
huge alignment values are unsupported
  %16 = load i64, ptr %8, align 70368744177664
huge alignment values are unsupported
  %26 = load i32, ptr %20, align 70368744177664
huge alignment values are unsupported
  %27 = load i32, ptr %19, align 70368744177664
huge alignment values are unsupported
  %37 = load i16, ptr %31, align 70368744177664
huge alignment values are unsupported
  %38 = load i16, ptr %30, align 70368744177664
huge alignment values are unsupported
  %146 = load i128, ptr %144, align 70368744177664
huge alignment values are unsupported
  %147 = load i128, ptr %145, align 70368744177664
in function _ZN17compiler_builtins3mem6memcmp17h39b65de6ac43991cE
LLVM ERROR: Broken function found, compilation aborted!
error: could not compile `compiler_builtins`
huge alignment values are unsupported
  %2 = load i32, huge alignment values are unsupportedptr
   %0, align %703687441776643 = load i
64, ptr %2, align 70368744177664
in function in function _ZN70_$LT$libc..unix..linux_like..in_addr$u20$as$u20$core..clone..Clone$GT$5clone17h3189a06ce16fa8eaE_ZN4libc4unix10linux_like5linux3gnu76_$LT$impl$u20$libc..unix..linux_like..linux..gnu..b64..x86_64..siginfo_t$GT$8si_value17h7c477f7ca72cc0a2E

LLVM ERROR: Broken function found, compilation aborted!LLVM ERROR: Broken function found, compilation aborted!

error: could not compile `libc`
Build completed unsuccessfully in 0:03:28

[nikic]

Could you please rerun the last rustc command (maybe you need to pass -v to get it) with -C save-temps and zip the *.bc files it produces?

[bryangarza]

Could you please rerun the last rustc command (maybe you need to pass -v to get it) with -C save-temps and zip the *.bc files it produces?

Here it is:
save-temps.zip

the command I ran

(I actually ran it twice because the first time I wasn't sure if it was working and then I later found where the *.bc files are stored.)

cd "/local/home/garzbrya/projects/rustc/issue-110467-safe-transmute2" && AR_x86_64_unknown_linux_gnu="ar" CARGO_INCREMENTAL="1" CARGO_PROFILE_RELEASE_DEBUG="0" CARGO_PROFILE_RELEASE_DEBUG_ASSERTIONS="false" CARGO_PROFILE_RELEASE_OVERFLOW_CHECKS="false" CARGO_TARGET_DIR="/local/home/garzbrya/projects/rustc/issue-110467-safe-transmute2/build/x86_64-unknown-linux-gnu/stage1-std" CC_x86_64_unknown_linux_gnu="cc" CFG_COMPILER_HOST_TRIPLE="x86_64-unknown-linux-gnu" CFG_RELEASE_CHANNEL="dev" CFLAGS_x86_64_unknown_linux_gnu="-ffunction-sections -fdata-sections -fPIC -m64" CXXFLAGS_x86_64_unknown_linux_gnu="-ffunction-sections -fdata-sections -fPIC -m64" CXX_x86_64_unknown_linux_gnu="c++" LIBC_CHECK_CFG="1" RANLIB_x86_64_unknown_linux_gnu="ar s" REAL_LIBRARY_PATH_VAR="LD_LIBRARY_PATH" RUSTBUILD_NATIVE_DIR="/local/home/garzbrya/projects/rustc/issue-110467-safe-transmute2/build/x86_64-unknown-linux-gnu/native" RUSTC="/local/home/garzbrya/projects/rustc/issue-110467-safe-transmute2/build/bootstrap/debug/rustc" RUSTC_BACKTRACE_ON_ICE="1" RUSTC_BOOTSTRAP="1" RUSTC_BREAK_ON_ICE="1" RUSTC_ERROR_METADATA_DST="/local/home/garzbrya/projects/rustc/issue-110467-safe-transmute2/build/tmp/extended-error-metadata" RUSTC_FORCE_UNSTABLE="1" RUSTC_INSTALL_BINDIR="bin" RUSTC_LIBDIR="/local/home/garzbrya/projects/rustc/issue-110467-safe-transmute2/build/x86_64-unknown-linux-gnu/stage1/lib" RUSTC_LINT_FLAGS="-Wrust_2018_idioms -Wunused_lifetimes -Wsemicolon_in_expressions_from_macros -Dwarnings" RUSTC_REAL="/local/home/garzbrya/projects/rustc/issue-110467-safe-transmute2/build/x86_64-unknown-linux-gnu/stage1/bin/rustc" RUSTC_SNAPSHOT="/local/home/garzbrya/projects/rustc/issue-110467-safe-transmute2/build/x86_64-unknown-linux-gnu/stage0/bin/rustc" RUSTC_SNAPSHOT_LIBDIR="/local/home/garzbrya/projects/rustc/issue-110467-safe-transmute2/build/x86_64-unknown-linux-gnu/stage0/lib" RUSTC_STAGE="1" RUSTC_SYSROOT="/local/home/garzbrya/projects/rustc/issue-110467-safe-transmute2/build/x86_64-unknown-linux-gnu/stage1" RUSTC_VERBOSE="1" RUSTDOC="/local/home/garzbrya/projects/rustc/issue-110467-safe-transmute2/build/bootstrap/debug/rustdoc" RUSTDOCFLAGS="-Csymbol-mangling-version=legacy -Zunstable-options -Zunstable-options --check-cfg=values(bootstrap) --check-cfg=values(stdarch_intel_sde) --check-cfg=values(no_fp_fmt_parse) --check-cfg=values(no_global_oom_handling) --check-cfg=values(no_rc) --check-cfg=values(no_sync) --check-cfg=values(freebsd12) --check-cfg=values(freebsd13) --check-cfg=values(backtrace_in_libstd) --check-cfg=values(target_env,"libnx") --check-cfg=values(target_arch,"asmjs","spirv","nvptx","xtensa","loongarch64") --check-cfg=values(target_env,"ohos") -Dwarnings -Wrustdoc::invalid_codeblock_attributes --crate-version 1.71.0-dev -Zcrate-attr=doc(html_root_url="https://doc.rust-lang.org/nightly/\")" RUSTDOC_REAL="/path/to/nowhere/rustdoc/not/required" RUSTFLAGS="-Csymbol-mangling-version=legacy -Zunstable-options -Zunstable-options --check-cfg=values(bootstrap) --check-cfg=values(stdarch_intel_sde) --check-cfg=values(no_fp_fmt_parse) --check-cfg=values(no_global_oom_handling) --check-cfg=values(no_rc) --check-cfg=values(no_sync) --check-cfg=values(freebsd12) --check-cfg=values(freebsd13) --check-cfg=values(backtrace_in_libstd) --check-cfg=values(target_env,"libnx") --check-cfg=values(target_arch,"asmjs","spirv","nvptx","xtensa","loongarch64") --check-cfg=values(target_env,"ohos") -Zmacro-backtrace -Clink-args=-Wl,-z,origin -Clink-args=-Wl,-rpath,$ORIGIN/../lib -Csplit-debuginfo=off -Cprefer-dynamic -Cllvm-args=-import-instr-limit=10 -Zinline-mir -Cembed-bitcode=yes -Clto=off -Csave-temps=yes -Zcrate-attr=doc(html_root_url="https://doc.rust-lang.org/nightly/\")" RUST_TEST_THREADS="96" WINAPI_NO_BUNDLED_LIBRARIES="1" __CARGO_DEFAULT_LIB_METADATA="devstd" "/local/home/garzbrya/projects/rustc/issue-110467-safe-transmute2/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "build" "--target" "x86_64-unknown-linux-gnu" "--release" "-Zcheck-cfg=names,values,output" "-Zbinary-dep-depinfo" "-j" "96" "-v" "--features" " panic-unwind backtrace" "--manifest-path" "/local/home/garzbrya/projects/rustc/issue-110467-safe-transmute2/library/test/Cargo.toml" "--message-format" "json-render-diagnostics"

[nikic]

Some of the optimized bitcode files do contain invalid alignments, but I did not manage to produce such corrupted files from the unoptimized bitcodes files.

[bryangarza]

Update: I used git bisect -- the LLVM 16 commit seems to be the one causing the error #109474

[bryangarza]

Seems setting download-ci-llvm = false in the config.toml allows the build to succeed without errors

[pnkfelix]

I did some reduction of the libc input and got things down to this, which reproduces the problem but only with the rustc that is built with download-ci-llvm=true:

#![feature(no_core, const_trait_impl, rustc_attrs, lang_items, fundamental, auto_traits)]
#![no_std]
#![no_core]
#![crate_type="rlib"]

#[lang = "copy"] trait Copy: Clone { }
#[lang = "clone"] trait Clone: Sized { fn clone(&self) -> Self; }
#[lang = "sized"] trait Sized { }
#[lang = "freeze"] unsafe auto trait Freeze {}
#[lang = "receiver"] trait Receiver { } impl<T: ?Sized> Receiver for &T {}

impl Copy for u8 {}
impl Copy for [u8; 1] {}
impl Clone for u8 { fn clone(&self) -> Self { *self } }
impl Clone for [u8; 1] { fn clone(&self) -> Self { *self } }

struct Pc { _size: [u8; 1], }
impl Copy for Pc {}
impl Clone for Pc { fn clone(&self) -> Pc { *self } }

Invocation:

./build/x86_64-unknown-linux-gnu/stage1/bin/rustc simple.rs -C opt-level=1 -Clto=false -C codegen-units=1 -C llvm-args=-opt-bisect-limit=10

Output:

BISECT: running pass (1) Annotation2MetadataPass on [module]
BISECT: running pass (2) ForceFunctionAttrsPass on [module]
BISECT: running pass (3) InferFunctionAttrsPass on [module]
BISECT: running pass (4) LowerExpectIntrinsicPass on _ZN36_$LT$u8$u20$as$u20$simple..Clone$GT$5clone17h3411880f7ff41262E
BISECT: running pass (5) SimplifyCFGPass on _ZN36_$LT$u8$u20$as$u20$simple..Clone$GT$5clone17h3411880f7ff41262E
BISECT: running pass (6) SROAPass on _ZN36_$LT$u8$u20$as$u20$simple..Clone$GT$5clone17h3411880f7ff41262E
BISECT: running pass (7) EarlyCSEPass on _ZN36_$LT$u8$u20$as$u20$simple..Clone$GT$5clone17h3411880f7ff41262E
BISECT: running pass (8) LowerExpectIntrinsicPass on _ZN57_$LT$$u5b$u8$u3b$$u20$1$u5d$$u20$as$u20$simple..Clone$GT$5clone17hfbbe4e8d0c1471c4E
BISECT: running pass (9) SimplifyCFGPass on _ZN57_$LT$$u5b$u8$u3b$$u20$1$u5d$$u20$as$u20$simple..Clone$GT$5clone17hfbbe4e8d0c1471c4E
BISECT: running pass (10) SROAPass on _ZN57_$LT$$u5b$u8$u3b$$u20$1$u5d$$u20$as$u20$simple..Clone$GT$5clone17hfbbe4e8d0c1471c4E
BISECT: NOT running pass (11) EarlyCSEPass on _ZN57_$LT$$u5b$u8$u3b$$u20$1$u5d$$u20$as$u20$simple..Clone$GT$5clone17hfbbe4e8d0c1471c4E
[...]
BISECT: NOT running pass (233) X86 LEA Fixup on function (_ZN36_$LT$u8$u20$as$u20$simple..Clone$GT$5clone17h3411880f7ff41262E)
huge alignment values are unsupported
  %2 = load i8, ptr %0, align 4611686018427387904
in function _ZN57_$LT$$u5b$u8$u3b$$u20$1$u5d$$u20$as$u20$simple..Clone$GT$5clone17hfbbe4e8d0c1471c4E
LLVM ERROR: Broken function found, compilation aborted!

[veera-sivarajan]

Running into this on commit f704f3b93b1543cf504ecca0052f9f8531b1f61f as well.

[nikic]

Per https://pkgs.org/search/?q=libstdc%2B%2B it looks like Amazon Linux 2 uses libstdc++ 7, which is ABI incompatible with the libLLVM.so for download-ci-llvm. I believe you need at least libstdc++ 8.

Possibly the build system should check the version.

[onur-ozkan]

Possibly the build system should check the version.

#125411 would catch this problem.

[onur-ozkan]

Per https://pkgs.org/search/?q=libstdc%2B%2B it looks like Amazon Linux 2 uses libstdc++ 7, which is ABI incompatible with the libLLVM.so for download-ci-llvm. I believe you need at least libstdc++ 8.

Possibly the build system should check the version.

Closing this as #125411 is merged and now the build system is capable of checking libstdc++ version. Feel free to re-open if needed.