rustc-LLVM ERROR of ControlFlowIntegrit

[zsdfbb]

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Hello, I am a beginner. I am testing the CFI of Rust (The Rust Unstable Book ControlFlowIntegrit), but I encountered this error log.

The error message is as follows:

Code

// This example demonstrates redirecting control flow using an indirect
// branch/call to a function with a different number of parameters than
// arguments intended/passed in the call/branch site.

use std::mem;

fn add_one(x: i32) -> i32 {
    x + 1
}

fn add_two(x: i32, _y: i32) -> i32 {
    x + 2
}

fn do_twice(f: fn(i32) -> i32, arg: i32) -> i32 {
    f(arg) + f(arg)
}

fn main() {
    let answer = do_twice(add_one, 5);

    println!("The answer is: {}", answer);

    println!("With CFI enabled, you should not see the next answer");
    let f: fn(i32) -> i32 =
        unsafe { mem::transmute::<*const u8, fn(i32) -> i32>(add_two as *const u8) };
    let next_answer = do_twice(f, 5);

    println!("The next answer is: {}", next_answer);
}

Meta

rustc --version --verbose:

$ rustc --version --verbose
rustc 1.89.0-nightly (d13a431a6 2025-06-09)
binary: rustc
commit-hash: d13a431a6cc69cd65efe7c3eb7808251d6fd7a46
commit-date: 2025-06-09
host: x86_64-unknown-linux-gnu
release: 1.89.0-nightly
LLVM version: 20.1.5

$ clang --version --verbose
Ubuntu clang version 18.1.3 (1ubuntu1)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin

$ uname -a
Linux ZSMSI 5.15.167.4-microsoft-standard-WSL2 #1 SMP Tue Nov 5 00:21:55 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux

Error output

$ RUSTFLAGS="-Clinker-plugin-lto -Clinker=clang -Clink-arg=-fuse-ld=lld -Zsanitizer=cfi" cargo run -Zbuild-std -Zbuild-std-features --release --target x86_64-unknown-linux-gnu

   Compiling compiler_builtins v0.1.160 (/home/zs/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/compiler-builtins/compiler-builtins)
   Compiling rustc-std-workspace-core v1.99.0 (/home/zs/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/rustc-std-workspace-core)
   Compiling alloc v0.0.0 (/home/zs/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc)
   Compiling panic_abort v0.0.0 (/home/zs/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/panic_abort)
   Compiling cfg-if v1.0.0
   Compiling libc v0.2.172
   Compiling rustc-demangle v0.1.24
rustc-LLVM ERROR: Do not know how to promote this operator!
error: could not compile `compiler_builtins` (lib)

Caused by:
  process didn't exit successfully: `/home/zs/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/rustc --crate-name compiler_builtins --edition=2024 /home/zs/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/compiler-builtins/compiler-builtins/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=80 --crate-type lib --emit=dep-info,metadata,link -C embed-bitcode=no -C debuginfo=2 --warn=unexpected_cfgs --check-cfg 'cfg(bootstrap)' --check-cfg 'cfg(target_os, values("cygwin"))' --cfg 'feature="compiler-builtins"' --cfg 'feature="default"' --cfg 'feature="rustc-dep-of-std"' --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values("c", "compiler-builtins", "default", "mangled-names", "mem", "no-asm", "no-f16-f128", "rustc-dep-of-std", "unstable-public-internals"))' -C metadata=dc0628facc0e0355 -C extra-filename=-6998363e595a805f --out-dir /home/zs/Develop/CfiTest/rust/rust-cfi-examples/rust-cfi-2/target/x86_64-unknown-linux-gnu/debug/deps --target x86_64-unknown-linux-gnu -Z force-unstable-if-unmarked -L dependency=/home/zs/Develop/CfiTest/rust/rust-cfi-examples/rust-cfi-2/target/x86_64-unknown-linux-gnu/debug/deps -L dependency=/home/zs/Develop/CfiTest/rust/rust-cfi-examples/rust-cfi-2/target/debug/deps --extern core=/home/zs/Develop/CfiTest/rust/rust-cfi-examples/rust-cfi-2/target/x86_64-unknown-linux-gnu/debug/deps/libcore-0f6e55509e6eb67a.rmeta --cap-lints allow -Clinker-plugin-lto -Clinker=clang -Clink-arg=-fuse-ld=lld -Zsanitizer=cfi --cfg f16_enabled --cfg f128_enabled --cfg intrinsics_enabled --cfg arch_enabled --cfg 'feature="unstable-intrinsics"' --cfg 'feature="mem-unaligned"' --check-cfg 'cfg(__ashldi3, values("optimized-c"))' --check-cfg 'cfg(__ashlsi3, values("optimized-c"))' --check-cfg 'cfg(__ashrdi3, values("optimized-c"))' --check-cfg 'cfg(__ashrsi3, values("optimized-c"))' --check-cfg 'cfg(__bswapsi2, values("optimized-c"))' --check-cfg 'cfg(__bswapdi2, values("optimized-c"))' --check-cfg 'cfg(__bswapti2, values("optimized-c"))' --check-cfg 'cfg(__divdi3, values("optimized-c"))' --check-cfg 'cfg(__divsi3, values("optimized-c"))' --check-cfg 'cfg(__divmoddi4, values("optimized-c"))' --check-cfg 'cfg(__divmodsi4, values("optimized-c"))' --check-cfg 'cfg(__divmodsi4, values("optimized-c"))' --check-cfg 'cfg(__divmodti4, values("optimized-c"))' --check-cfg 'cfg(__lshrdi3, values("optimized-c"))' --check-cfg 'cfg(__lshrsi3, values("optimized-c"))' --check-cfg 'cfg(__moddi3, values("optimized-c"))' --check-cfg 'cfg(__modsi3, values("optimized-c"))' --check-cfg 'cfg(__muldi3, values("optimized-c"))' --check-cfg 'cfg(__udivdi3, values("optimized-c"))' --check-cfg 'cfg(__udivmoddi4, values("optimized-c"))' --check-cfg 'cfg(__udivmodsi4, values("optimized-c"))' --check-cfg 'cfg(__udivsi3, values("optimized-c"))' --check-cfg 'cfg(__umoddi3, values("optimized-c"))' --check-cfg 'cfg(__umodsi3, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas1_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas1_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas1_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas1_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas2_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas2_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas2_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas2_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas4_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas4_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas4_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas4_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas8_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas8_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas8_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas8_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas16_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas16_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas16_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas16_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd1_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd1_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd1_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd1_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd2_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd2_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd2_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd2_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd4_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd4_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd4_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd4_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd8_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd8_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd8_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd8_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr1_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr1_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr1_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr1_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr2_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr2_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr2_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr2_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr4_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr4_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr4_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr4_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr8_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr8_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr8_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr8_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor1_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor1_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor1_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor1_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor2_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor2_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor2_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor2_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor4_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor4_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor4_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor4_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor8_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor8_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor8_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor8_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset1_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset1_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset1_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset1_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset2_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset2_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset2_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset2_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset4_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset4_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset4_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset4_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset8_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset8_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset8_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset8_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp1_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp1_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp1_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp1_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp2_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp2_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp2_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp2_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp4_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp4_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp4_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp4_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp8_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp8_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp8_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp8_acq_rel, values("optimized-c"))' --check-cfg 'cfg(target_feature, values("vis3"))' --check-cfg 'cfg(feature, values("checked"))' --check-cfg 'cfg(assert_no_panic)' --check-cfg 'cfg(f16_enabled)' --check-cfg 'cfg(f128_enabled)' --check-cfg 'cfg(thumb)' --check-cfg 'cfg(thumb_1)' --check-cfg 'cfg(intrinsics_enabled)' --check-cfg 'cfg(arch_enabled)' --check-cfg 'cfg(optimizations_enabled)' --check-cfg 'cfg(feature, values("unstable-public-internals"))' --check-cfg 'cfg(optimizations_enabled)' --check-cfg 'cfg(x86_no_sse)' --check-cfg 'cfg(kernel_user_helpers)' --check-cfg 'cfg(feature, values("mem-unaligned"))'` (exit status: 101)
warning: build failed, waiting for other jobs to finish...

Backtrace

$ RUST_BACKTRACE=1
$ RUSTFLAGS="-Clinker-plugin-lto -Clinker=clang -Clink-arg=-fuse-ld=lld -Zsanitizer=cfi" cargo run -Zbuild-std -Zbuild-std-features --release --target x86_64-unknown-linux-gnu

   Compiling compiler_builtins v0.1.160 (/home/zs/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/compiler-builtins/compiler-builtins)
   Compiling rustc-std-workspace-core v1.99.0 (/home/zs/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/rustc-std-workspace-core)
   Compiling alloc v0.0.0 (/home/zs/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc)
   Compiling panic_abort v0.0.0 (/home/zs/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/panic_abort)
   Compiling cfg-if v1.0.0
   Compiling libc v0.2.172
   Compiling rustc-demangle v0.1.24
rustc-LLVM ERROR: Do not know how to promote this operator!
error: could not compile `compiler_builtins` (lib)

Caused by:
  process didn't exit successfully: `/home/zs/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/rustc --crate-name compiler_builtins --edition=2024 /home/zs/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/compiler-builtins/compiler-builtins/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=82 --crate-type lib --emit=dep-info,metadata,link -C opt-level=3 -C embed-bitcode=no --warn=unexpected_cfgs --check-cfg 'cfg(bootstrap)' --check-cfg 'cfg(target_os, values("cygwin"))' --cfg 'feature="compiler-builtins"' --cfg 'feature="default"' --cfg 'feature="rustc-dep-of-std"' --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values("c", "compiler-builtins", "default", "mangled-names", "mem", "no-asm", "no-f16-f128", "rustc-dep-of-std", "unstable-public-internals"))' -C metadata=f9ff92ee632bac5e -C extra-filename=-9c78bddfac14b282 --out-dir /home/zs/Develop/CfiTest/rust/rust-cfi-examples/rust-cfi-2/target/x86_64-unknown-linux-gnu/release/deps --target x86_64-unknown-linux-gnu -C strip=debuginfo -Z force-unstable-if-unmarked -L dependency=/home/zs/Develop/CfiTest/rust/rust-cfi-examples/rust-cfi-2/target/x86_64-unknown-linux-gnu/release/deps -L dependency=/home/zs/Develop/CfiTest/rust/rust-cfi-examples/rust-cfi-2/target/release/deps --extern core=/home/zs/Develop/CfiTest/rust/rust-cfi-examples/rust-cfi-2/target/x86_64-unknown-linux-gnu/release/deps/libcore-f03378565b56c52d.rmeta --cap-lints allow -Clinker-plugin-lto -Clinker=clang -Clink-arg=-fuse-ld=lld -Zsanitizer=cfi --cfg f16_enabled --cfg f128_enabled --cfg intrinsics_enabled --cfg arch_enabled --cfg optimizations_enabled --cfg 'feature="unstable-intrinsics"' --cfg 'feature="mem-unaligned"' --check-cfg 'cfg(__ashldi3, values("optimized-c"))' --check-cfg 'cfg(__ashlsi3, values("optimized-c"))' --check-cfg 'cfg(__ashrdi3, values("optimized-c"))' --check-cfg 'cfg(__ashrsi3, values("optimized-c"))' --check-cfg 'cfg(__bswapsi2, values("optimized-c"))' --check-cfg 'cfg(__bswapdi2, values("optimized-c"))' --check-cfg 'cfg(__bswapti2, values("optimized-c"))' --check-cfg 'cfg(__divdi3, values("optimized-c"))' --check-cfg 'cfg(__divsi3, values("optimized-c"))' --check-cfg 'cfg(__divmoddi4, values("optimized-c"))' --check-cfg 'cfg(__divmodsi4, values("optimized-c"))' --check-cfg 'cfg(__divmodsi4, values("optimized-c"))' --check-cfg 'cfg(__divmodti4, values("optimized-c"))' --check-cfg 'cfg(__lshrdi3, values("optimized-c"))' --check-cfg 'cfg(__lshrsi3, values("optimized-c"))' --check-cfg 'cfg(__moddi3, values("optimized-c"))' --check-cfg 'cfg(__modsi3, values("optimized-c"))' --check-cfg 'cfg(__muldi3, values("optimized-c"))' --check-cfg 'cfg(__udivdi3, values("optimized-c"))' --check-cfg 'cfg(__udivmoddi4, values("optimized-c"))' --check-cfg 'cfg(__udivmodsi4, values("optimized-c"))' --check-cfg 'cfg(__udivsi3, values("optimized-c"))' --check-cfg 'cfg(__umoddi3, values("optimized-c"))' --check-cfg 'cfg(__umodsi3, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas1_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas1_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas1_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas1_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas2_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas2_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas2_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas2_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas4_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas4_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas4_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas4_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas8_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas8_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas8_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas8_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas16_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas16_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas16_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_cas16_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd1_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd1_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd1_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd1_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd2_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd2_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd2_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd2_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd4_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd4_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd4_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd4_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd8_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd8_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd8_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldadd8_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr1_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr1_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr1_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr1_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr2_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr2_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr2_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr2_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr4_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr4_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr4_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr4_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr8_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr8_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr8_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldclr8_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor1_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor1_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor1_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor1_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor2_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor2_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor2_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor2_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor4_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor4_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor4_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor4_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor8_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor8_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor8_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldeor8_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset1_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset1_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset1_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset1_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset2_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset2_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset2_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset2_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset4_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset4_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset4_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset4_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset8_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset8_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset8_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_ldset8_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp1_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp1_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp1_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp1_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp2_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp2_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp2_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp2_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp4_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp4_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp4_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp4_acq_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp8_relax, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp8_acq, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp8_rel, values("optimized-c"))' --check-cfg 'cfg(__aarch64_swp8_acq_rel, values("optimized-c"))' --check-cfg 'cfg(target_feature, values("vis3"))' --check-cfg 'cfg(feature, values("checked"))' --check-cfg 'cfg(assert_no_panic)' --check-cfg 'cfg(f16_enabled)' --check-cfg 'cfg(f128_enabled)' --check-cfg 'cfg(thumb)' --check-cfg 'cfg(thumb_1)' --check-cfg 'cfg(intrinsics_enabled)' --check-cfg 'cfg(arch_enabled)' --check-cfg 'cfg(optimizations_enabled)' --check-cfg 'cfg(feature, values("unstable-public-internals"))' --check-cfg 'cfg(optimizations_enabled)' --check-cfg 'cfg(x86_no_sse)' --check-cfg 'cfg(kernel_user_helpers)' --check-cfg 'cfg(feature, values("mem-unaligned"))'` (exit status: 101)
warning: build failed, waiting for other jobs to finish...

[cyrgani]

This error can be caused just by RUSTFLAGS="-Clinker-plugin-lto -Zsanitizer=cfi" cargo b on an empty crate with the compiler_builtins = "=0.1.160" dependency. It is only caused by compiler_builtins v0.1.157 and above, 0.1.156 compiles sucessfully.

reduction of compiler_builtins:

#![no_builtins]
#![no_std]

static FUNC: fn() = initializer;

fn initializer() {
    call(fma_with_fma);
}

fn call(fn_ptr: fn()) {
    fn_ptr();
}

fn fma_with_fma() {}

[cyrgani]

seems to require just rustc -Clinker-plugin-lto -Zsanitizer=cfi src/main.rs

#![no_builtins]

fn main() {}

[saethlin]

Your second example looks smaller but it's actually bigger. Since it's a bin crate without no_std it pulls in our pre-main initialization code which does dispatch through a function pointer.

[workingjubilee]

huh.

cc @rcvalle @maurer

[maurer]

Interestingly, it only triggers for cfi, not kcfi (which is probably why I hadn't noticed it, my day-to-day usage of the feature only hits kcfi).

mmaurer@joyeuse:~/rustc-repro$ rustc +nightly -Clinker-plugin-lto -Zsanitizer=cfi scratch.rs --crate-type=rlib -C panic=abort --cap-lints=allow
rustc-LLVM ERROR: Do not know how to promote this operator!
mmaurer@joyeuse:~/rustc-repro$ rustc +nightly -Cpanic=abort -Zsanitizer=kcfi scratch.rs --crate-type=rlib --cap-lints=allow
mmaurer@joyeuse:~/rustc-repro$ 

[maurer]

Switching from -Clinker-plugin-lto to -Clto -Ccodegen-units=1 also suppresses the error.

[maurer]

mmaurer@joyeuse:~/rustc-repro$ cat check.sh 
#!/usr/bin/env bash
rustc -Clinker-plugin-lto -Zsanitizer=cfi scratch.rs --crate-type=rlib -C panic=abort --cap-lints=allow
mmaurer@joyeuse:~/rustc-repro$ cargo-bisect-rustc --script check.sh

SNIP

looking for regression commit between 2024-01-12 and 2024-01-13
fetching (via remote github) commits from max(62d7ed4a6775c4490e493093ca98ef7c215b835b, 2024-01-10) to 2319be8e265dd19973574eb581d28297baf44b11
ending github query because we found starting sha: 62d7ed4a6775c4490e493093ca98ef7c215b835b
get_commits_between returning commits, len: 8
  commit[0] 2024-01-11: Auto merge of #119864 - matthiaskrgr:rollup-mc2qz13, r=matthiaskrgr
  commit[1] 2024-01-12: Auto merge of #119430 - NCGThompson:int-pow-bench, r=cuviper
  commit[2] 2024-01-12: Auto merge of #118548 - Enselic:bench-padding, r=thomcc,ChrisDenton
  commit[3] 2024-01-12: Auto merge of #119735 - lcnr:provisional-cache-readd, r=compiler-errors
  commit[4] 2024-01-12: Auto merge of #119879 - matthiaskrgr:rollup-y710der, r=matthiaskrgr
  commit[5] 2024-01-12: Auto merge of #119396 - Nadrieril:intersection-tracking, r=WaffleLapkin
  commit[6] 2024-01-12: Auto merge of #119889 - GuillaumeGomez:rollup-ah3dhya, r=GuillaumeGomez
  commit[7] 2024-01-12: Auto merge of #119452 - AngelicosPhosphoros:make_nonzeroint_get_assume_nonzero, r=scottmcm
ERROR: no CI builds available between 62d7ed4a6775c4490e493093ca98ef7c215b835b and 2319be8e265dd19973574eb581d28297baf44b11 within last 167 days

Taking a quick glance through those, the one that seems most relevant is #119889 , as it contains #119885 which reverts #113923 . This basically suggests that the core problem is that #[no_builtins] crates are not participating in linker-plugin-LTO, which means that if they get a CFI bundle that is supposed to be lowered in LTO, the build fails.

This likely means that until compiler_builtins v0.1.57, there were no indirect jumps in compiler builtins, so this didn't trigger.

The fact that it doesn't trigger with -Clto makes me wonder if there's something funny going on with the suppression of one vs the other for builtins?

[maurer]

compiler_builtins triggers this by switching to a function pointer for run-time feature detection.

It appears that linker-plugin-lto selects bitcode emission differently than -Clto, which is why it breaks.

If -Clto is working, I think we may not need that particular adaptation, but given the fragility of compiler_builtins / #![no_builtins] in general, it's hard to be certain. I've sent up #142323 to try that approach out - it does fix this bug, but we probably need to poke at it to make sure it doesn't break other build configurations.

[dianqk]

Interestingly, it only triggers for cfi, not kcfi (which is probably why I hadn't noticed it, my day-to-day usage of the feature only hits kcfi).

mmaurer@joyeuse:~/rustc-repro$ rustc +nightly -Clinker-plugin-lto -Zsanitizer=cfi scratch.rs --crate-type=rlib -C panic=abort --cap-lints=allow
rustc-LLVM ERROR: Do not know how to promote this operator!
mmaurer@joyeuse:~/rustc-repro$ rustc +nightly -Cpanic=abort -Zsanitizer=kcfi scratch.rs --crate-type=rlib --cap-lints=allow
mmaurer@joyeuse:~/rustc-repro$ 

It seems that kcfi doesn't require LTO:

To enable Clang’s available CFI schemes, use the flag -fsanitize=cfi. You can also enable a subset of available schemes. As currently implemented, all schemes except for kcfi rely on link-time optimization (LTO); so it is required to specify -flto or -flto=thin, and the linker used must support LTO, for example via the gold plugin. (https://clang.llvm.org/docs/ControlFlowIntegrity.html)

[maurer]

Yes, that was in my initial assessment - I didn't know it was LTO related at that point and thought it might have just been sanitizer related, so I tried with KCFI to see if that would trigger it in a more reduced sense.

[rcvalle]

@rustbot claim

[RalfJung]

Reopening since https://github.com/rust-lang/rust/pull/145368 is getting reverted in https://github.com/rust-lang/rust/pull/146133.