18 lines
466 B
Rust
18 lines
466 B
Rust
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#![crate_type = "cdylib"]
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#![crate_name = "foo"]
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extern "C" fn ret32() -> i32 {
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32
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}
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#[no_mangle]
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pub extern "C" fn foo(ptr: extern "C" fn(extern "C" fn() -> i32)) {
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assert_eq!((ptr as usize) >> 56, 0x1f);
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// Store an arbitrary tag in the tag bits, and convert back to the correct pointer type.
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let p = ((ret32 as usize) | (0x2f << 56)) as *const ();
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let p: extern "C" fn() -> i32 = unsafe { std::mem::transmute(p) };
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unsafe { ptr(p) }
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}
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