`riscv32gc-*` targets produce a synthetic object file (`symbols.o`) with a mismatching floating-point ABI #104284

yvt · 2022-11-11T14:21:25Z

I tried this code:

cargo new --lib hoge
cd hoge

cat >> Cargo.toml <<EOF
[lib]
crate-type = ["cdylib"]
EOF

cat > src/lib.rs <<EOF
#![no_std]
#[no_mangle]
pub extern "C" fn add(left: usize, right: usize) -> usize {
    left + right
}

#[panic_handler]
fn panic(_: &core::panic::PanicInfo) -> ! {
    loop {}
}
EOF

env RUSTFLAGS='-Cpanic=abort -Clinker=rust-lld' cargo build --target riscv32gc-unknown-linux-gnu -Zbuild-std

I expected to see this happen: Successful compilation (because this would succeed for the target riscv64gc-unknown-linux-gnu)

Instead, this happened:

error: linking with `rust-lld` failed: exit status: 1
  |
  = note: "rust-lld" "-flavor" "gnu" "--version-script=/tmp/rustcDiidlE/list" "/tmp/rustcDiidlE/symbols.o" "/tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/hoge.92rzut19pk7sei6.rcgu.o" "--as-needed" "-L" "/tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps" "-L" "/tmp/hoge/target/debug/deps" "-L" "/home/USER/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/riscv32gc-unknown-linux-gnu/lib" "-Bstatic" "/tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/librustc_std_workspace_core-4ec574d8efc1d5b8.rlib" "/tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/libcore-572ea5c6b4d30279.rlib" "/tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/libcompiler_builtins-c685b409872aa5db.rlib" "-Bdynamic" "--eh-frame-hdr" "-znoexecstack" "-L" "/home/USER/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/riscv32gc-unknown-linux-gnu/lib" "-o" "/tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/libhoge.so" "--gc-sections" "-shared" "-zrelro" "-znow"
  = note: rust-lld: error: /tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/hoge.92rzut19pk7sei6.rcgu.o: cannot link object files with different floating-point ABI
          rust-lld: error: /tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/libcore-572ea5c6b4d30279.rlib(core-572ea5c6b4d30279.core.efcbc3e8-cgu.3.rcgu.o): cannot link object files with different floating-point ABI
          rust-lld: error: /tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/libcore-572ea5c6b4d30279.rlib(core-572ea5c6b4d30279.core.efcbc3e8-cgu.10.rcgu.o): cannot link object files with different floating-point ABI
          rust-lld: error: /tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/libcore-572ea5c6b4d30279.rlib(core-572ea5c6b4d30279.core.efcbc3e8-cgu.0.rcgu.o): cannot link object files with different floating-point ABI
          rust-lld: error: /tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/libcore-572ea5c6b4d30279.rlib(core-572ea5c6b4d30279.core.efcbc3e8-cgu.2.rcgu.o): cannot link object files with different floating-point ABI
          rust-lld: error: /tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/libcore-572ea5c6b4d30279.rlib(core-572ea5c6b4d30279.core.efcbc3e8-cgu.15.rcgu.o): cannot link object files with different floating-point ABI
          rust-lld: error: /tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/libcore-572ea5c6b4d30279.rlib(core-572ea5c6b4d30279.core.efcbc3e8-cgu.13.rcgu.o): cannot link object files with different floating-point ABI
          rust-lld: error: /tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/libcore-572ea5c6b4d30279.rlib(core-572ea5c6b4d30279.core.efcbc3e8-cgu.11.rcgu.o): cannot link object files with different floating-point ABI
          rust-lld: error: /tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/libcore-572ea5c6b4d30279.rlib(core-572ea5c6b4d30279.core.efcbc3e8-cgu.14.rcgu.o): cannot link object files with different floating-point ABI
          rust-lld: error: /tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/libcore-572ea5c6b4d30279.rlib(core-572ea5c6b4d30279.core.efcbc3e8-cgu.1.rcgu.o): cannot link object files with different floating-point ABI
          rust-lld: error: /tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/libcore-572ea5c6b4d30279.rlib(core-572ea5c6b4d30279.core.efcbc3e8-cgu.12.rcgu.o): cannot link object files with different floating-point ABI
          rust-lld: error: /tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/libcore-572ea5c6b4d30279.rlib(core-572ea5c6b4d30279.core.efcbc3e8-cgu.4.rcgu.o): cannot link object files with different floating-point ABI
          rust-lld: error: /tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/libcore-572ea5c6b4d30279.rlib(core-572ea5c6b4d30279.core.efcbc3e8-cgu.5.rcgu.o): cannot link object files with different floating-point ABI
          rust-lld: error: /tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/libcore-572ea5c6b4d30279.rlib(core-572ea5c6b4d30279.core.efcbc3e8-cgu.6.rcgu.o): cannot link object files with different floating-point ABI
          rust-lld: error: /tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/libcore-572ea5c6b4d30279.rlib(core-572ea5c6b4d30279.core.efcbc3e8-cgu.7.rcgu.o): cannot link object files with different floating-point ABI
          rust-lld: error: /tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/libcore-572ea5c6b4d30279.rlib(core-572ea5c6b4d30279.core.efcbc3e8-cgu.9.rcgu.o): cannot link object files with different floating-point ABI
          rust-lld: error: /tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/libcompiler_builtins-c685b409872aa5db.rlib(compiler_builtins-c685b409872aa5db.compiler_builtins.53485fab-cgu.11.rcgu.o): cannot link object files with different floating-point ABI
          rust-lld: error: /tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/libcompiler_builtins-c685b409872aa5db.rlib(compiler_builtins-c685b409872aa5db.compiler_builtins.53485fab-cgu.0.rcgu.o): cannot link object files with different floating-point ABI
          rust-lld: error: /tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/libcompiler_builtins-c685b409872aa5db.rlib(compiler_builtins-c685b409872aa5db.compiler_builtins.53485fab-cgu.12.rcgu.o): cannot link object files with different floating-point ABI
          rust-lld: error: /tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/libcompiler_builtins-c685b409872aa5db.rlib(compiler_builtins-c685b409872aa5db.compiler_builtins.53485fab-cgu.15.rcgu.o): cannot link object files with different floating-point ABI
          rust-lld: error: too many errors emitted, stopping now (use --error-limit=0 to see all errors)

$ file /tmp/rustcVXpC3S/symbols.o
/tmp/rustcVXpC3S/symbols.o: ELF 32-bit LSB relocatable, UCB RISC-V, soft-float ABI, version 1 (SYSV), not stripped

$ file /tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/hoge.92rzut19pk7sei6.rcgu.o
/tmp/hoge/target/riscv32gc-unknown-linux-gnu/debug/deps/hoge.92rzut19pk7sei6.rcgu.o: ELF 32-bit LSB relocatable, UCB RISC-V, RVC, double-float ABI, version 1 (SYSV), with debug_info, not stripped

Meta

rustc --version --verbose:

rustc 1.66.0-nightly (a6b7274a4 2022-10-10)
binary: rustc
commit-hash: a6b7274a462829f8ef08a1ddcdcec7ac80dbf3e1
commit-date: 2022-10-10
host: x86_64-unknown-linux-gnu
release: 1.66.0-nightly
LLVM version: 15.0.2

The text was updated successfully, but these errors were encountered:

bjorn3 · 2022-11-11T17:17:28Z

The relevant code is

rust/compiler/rustc_codegen_ssa/src/back/metadata.rs

Lines 168 to 174 in 742d3f0

    
           Architecture::Riscv64 if sess.target.options.features.contains("+d") => { 
        
               // copied from `riscv64-linux-gnu-gcc foo.c -c`, note though 
        
               // that the `+d` target feature represents whether the double 
        
               // float abi is enabled. 
        
               let e_flags = elf::EF_RISCV_RVC | elf::EF_RISCV_FLOAT_ABI_DOUBLE; 
        
               e_flags 
        
           }

It should probably be applied to riscv32 too

FawazTirmizi · 2022-12-20T21:53:01Z

Doesn't seem like anyone else has picked this up yet, if it's as simple a fix as it seems I would be happy to make the PR.

FawazTirmizi · 2023-01-09T07:59:08Z

@rustbot claim

…bjorn3 riscv: Fix ELF header flags The previous version added both `EF_RISCV_FLOAT_ABI_DOUBLE` and `EF_RISCV_RVC` if the "D" extension was enabled on riscv64 targets. riscv32 targets were not accounted for. This patch changes this so that: - Only add `EF_RISCV_RVC` if the "C" extension is enabled - Add `EF_RISCV_FLOAT_ABI_SINGLE` if the "F" extension is enabled and the "D" extension is not - Add these ELF flags for riscv32 as well Fixes rust-lang#104284 r? rust-lang/risc-v

yvt · 2023-01-15T08:55:46Z

The mismatch still occurs if extra features are specified by -C (e.g., -C target-feature=+f,+d).

FawazTirmizi · 2023-03-02T05:22:09Z

Sorry about the delayed response. I just tested it, but I'm not seeing the error. Could you test again as well? I was running the following command:
env RUSTFLAGS='-Cpanic=abort -Clinker=rust-lld -C target-feature=+f,+d' cargo build --target riscv32gc-unknown-linux-gnu -Zbuild-std

Here is the version I'm on:

rustc 1.69.0-nightly (f77bfb733 2023-03-01)
binary: rustc
commit-hash: f77bfb7336f21bfe6a5fb5f7358d4406e2597289
commit-date: 2023-03-01
host: x86_64-unknown-linux-gnu
release: 1.69.0-nightly
LLVM version: 15.0.7

yvt · 2023-03-08T16:25:10Z

Hm, I actually encountered the issue in a more complicated setup (CI run) with bare-metal targets and assumed from the symptom that it was caused by a similar underlying problem. I'll look into it again and open a separate issue after getting a better idea.

yvt added the C-bug Category: This is a bug. label Nov 11, 2022

yvt mentioned this issue Nov 11, 2022

Update the target compiler version to nightly-2022-08-18 or later r3-os/r3#9

Closed

yvt changed the title ~~riscv32gc-*targets produce a synthetic object file (symbols.o) with a mismatching floating-point ABI~~ riscv32gc-* targets produce a synthetic object file (symbols.o) with a mismatching floating-point ABI Nov 11, 2022

bjorn3 added A-linkage Area: linking into static, shared libraries and binaries O-riscv Target: RISC-V architecture A-ABI Area: Concerning the application binary interface (ABI) A-floating-point Area: Floating point numbers and arithmetic labels Nov 11, 2022

rustbot assigned FawazTirmizi Jan 9, 2023

FawazTirmizi mentioned this issue Jan 13, 2023

riscv: Fix ELF header flags #106797

Merged

bors closed this as completed in 278e02a Jan 14, 2023

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`riscv32gc-*` targets produce a synthetic object file (`symbols.o`) with a mismatching floating-point ABI #104284

`riscv32gc-*` targets produce a synthetic object file (`symbols.o`) with a mismatching floating-point ABI #104284

yvt commented Nov 11, 2022 •

edited by rustbot

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bjorn3 commented Nov 11, 2022

FawazTirmizi commented Dec 20, 2022

FawazTirmizi commented Jan 9, 2023

yvt commented Jan 15, 2023

FawazTirmizi commented Mar 2, 2023

yvt commented Mar 8, 2023 •

edited

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riscv32gc-* targets produce a synthetic object file (symbols.o) with a mismatching floating-point ABI #104284

riscv32gc-* targets produce a synthetic object file (symbols.o) with a mismatching floating-point ABI #104284

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yvt commented Nov 11, 2022 • edited by rustbot Loading

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bjorn3 commented Nov 11, 2022

FawazTirmizi commented Dec 20, 2022

FawazTirmizi commented Jan 9, 2023

yvt commented Jan 15, 2023

FawazTirmizi commented Mar 2, 2023

yvt commented Mar 8, 2023 • edited Loading

`riscv32gc-*` targets produce a synthetic object file (`symbols.o`) with a mismatching floating-point ABI #104284

`riscv32gc-*` targets produce a synthetic object file (`symbols.o`) with a mismatching floating-point ABI #104284

yvt commented Nov 11, 2022 •

edited by rustbot

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yvt commented Mar 8, 2023 •

edited

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