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64 lines
2.0 KiB
Rust
64 lines
2.0 KiB
Rust
//@ normalize-stderr-test: "(abi|pref|unadjusted_abi_align): Align\([1-8] bytes\)" -> "$1: $$SOME_ALIGN"
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/*!
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C doesn't have zero-sized types... except it does.
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Standard C doesn't, but some C compilers, like GCC, implement ZSTs as a compiler extension.
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This historically has wound up interacting with processor-specific ABIs in fairly ad-hoc ways.
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e.g. despite being "zero-sized", sometimes C compilers decide ZSTs consume registers.
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That means these two function signatures may not be compatible:
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```
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extern "C" fn((), i32, i32);
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extern "C" fn(i32, (), i32);
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```
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*/
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/*
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* ZST IN "C" IS ZERO-SIZED
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*/
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//@ revisions: aarch64-darwin
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//@[aarch64-darwin] compile-flags: --target aarch64-apple-darwin
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//@[aarch64-darwin] needs-llvm-components: aarch64
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//@ revisions: x86_64-linux
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//@[x86_64-linux] compile-flags: --target x86_64-unknown-linux-gnu
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//@[x86_64-linux] needs-llvm-components: x86
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/*
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* ZST IN "C" IS PASS-BY-POINTER
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*/
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// according to the SRV4 ABI, an aggregate is always passed in registers,
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// and it so happens the GCC extension for ZSTs considers them as structs.
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//@ revisions: powerpc-linux
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//@[powerpc-linux] compile-flags: --target powerpc-unknown-linux-gnu
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//@[powerpc-linux] needs-llvm-components: powerpc
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//@ revisions: s390x-linux
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//@[s390x-linux] compile-flags: --target s390x-unknown-linux-gnu
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//@[s390x-linux] needs-llvm-components: systemz
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//@ revisions: sparc64-linux
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//@[sparc64-linux] compile-flags: --target sparc64-unknown-linux-gnu
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//@[sparc64-linux] needs-llvm-components: sparc
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// The Win64 ABI uses slightly different handling for power-of-2 sizes in the ABI,
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// so GCC decided that ZSTs are pass-by-pointer, as `0.is_power_of_two() == false`
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//@ revisions: x86_64-pc-windows-gnu
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//@[x86_64-pc-windows-gnu] compile-flags: --target x86_64-pc-windows-gnu
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//@[x86_64-pc-windows-gnu] needs-llvm-components: x86
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#![feature(lang_items, no_core, rustc_attrs)]
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#![no_core]
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#![crate_type = "lib"]
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#[lang = "sized"]
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trait Sized {}
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#[rustc_abi(debug)]
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extern "C" fn pass_zst(_: ()) {} //~ ERROR: fn_abi
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