multiple rlib candidates for `compiler_builtins` found

[jiayihu]

I'm having a similar issue to #334 but it's different I think. I have build-std = ["core", "alloc"] in config.toml and I'm trying to compile a local patch of compiler-builtins, for the reasons stated in #387 . In Cargo.toml I have the following configuration:

wasm3 = { version = "0.1.3", default-features = false, features = ["use-32bit-slots"] }
compiler_builtins = { version = "0.1.36" }

[patch.crates-io]
wasm3 = { path = "../../wasm3-rs" }
compiler_builtins = { path = "../../compiler-builtins" }

But the compiler is giving the error:

error[E0465]: multiple rlib candidates for `compiler_builtins` found
  |
  = note: candidate #1: /Users/jiayihu/Desktop/Repo/fedra-thesis/fedra/target/thumbv7em-none-eabi/debug/deps/libcompiler_builtins-c00a7bd3257465d5.rlib
  = note: candidate #2: /Users/jiayihu/Desktop/Repo/fedra-thesis/fedra/target/thumbv7em-none-eabi/debug/deps/libcompiler_builtins-7cae6c5d923380b0.rlib

I believe one version is the one included by default by cargo because of core in https://github.com/rust-lang/cargo/blob/master/src/cargo/core/compiler/standard_lib.rs#L28, whereas the second one is my patch. How do I opt-out the cargo-inserted one?

[yuanyuan2100]

Got the same error when I was complying for avr-atmega328p.

= note: candidate #1: /Rust/arduino/target/avr-atmega328p/release/deps/libcompiler_builtins-13aec7bae4adb9d2.rlib
= note: candidate #2: /Rust/arduino/target/avr-atmega328p/release/deps/libcompiler_builtins-a98f3389f6f9d633.rlib

[haraldh]

maybe this helps:

[build]
rustflags = [
    "-C", "link-self-contained=no",
]

[stlankes]

I have a similar problem and the compiler flag doesn't help.

[nbdd0121]

This workaround works for me: add

[unstable]
build-std = ["core", "alloc"]
build-std-features = ["compiler-builtins-mangled-names"]

to .cargo/config and use

[dependencies]
compiler_builtins_local = { path = "../../compiler-builtins", package = "compiler_builtins" }

to Cargo.toml and add

extern crate compiler_builtins_local;

to the top of main.rs.

[bjorn3]

build-std-features = ["compiler-builtins-mangled-names"]

I am not quite sure this was intended to work with -Zbuild-std. At the very least it wouldn't be possible to provide any stability guarantees as a codegen backend is free to depend on new intrinsics from compiler-builtins.

[tgross35]

This is a pretty old issue and it seems like there are solutions, so I will close this.