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Fix CFI: f32 and f64 are encoded incorrectly for c

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Fix #115150 by encoding f32 and f64 correctly for cross-language CFI. I
missed changing the encoding for f32 and f64 when I introduced the
integer normalization option in #105452 as integer normalization does
not include floating point. `f32` and `f64` should be always encoded as
`f` and `d` since they are both FFI safe when their representation are
the same (i.e., IEEE 754) for both the Rust compiler and Clang.
This commit is contained in:
Ramon de C Valle 2023-08-23 16:02:25 -07:00
parent 249595b752
commit 5d6e2d7050
2 changed files with 19 additions and 10 deletions
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17
compiler/rustc_symbol_mangling/src/typeid/typeid_itanium_cxx_abi.rs
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@ -447,7 +447,7 @@ fn encode_ty<'tcx>(
typeid.push('b');
}
ty::Int(..) | ty::Uint(..) | ty::Float(..) => {
ty::Int(..) | ty::Uint(..) => {
// u<length><type-name> as vendor extended type
let mut s = String::from(match ty.kind() {
ty::Int(IntTy::I8) => "u2i8",
@ -462,14 +462,23 @@ fn encode_ty<'tcx>(
ty::Uint(UintTy::U64) => "u3u64",
ty::Uint(UintTy::U128) => "u4u128",
ty::Uint(UintTy::Usize) => "u5usize",
ty::Float(FloatTy::F32) => "u3f32",
ty::Float(FloatTy::F64) => "u3f64",
_ => "",
_ => bug!("encode_ty: unexpected `{:?}`", ty.kind()),
});
compress(dict, DictKey::Ty(ty, TyQ::None), &mut s);
typeid.push_str(&s);
}
// Rust's f32 and f64 single (32-bit) and double (64-bit) precision floating-point types
// have IEEE-754 binary32 and binary64 floating-point layouts, respectively.
//
// (See https://rust-lang.github.io/unsafe-code-guidelines/layout/scalars.html#fixed-width-floating-point-types.)
ty::Float(float_ty) => {
typeid.push(match float_ty {
FloatTy::F32 => 'f',
FloatTy::F64 => 'd',
});
}
ty::Char => {
// u4char as vendor extended type
let mut s = String::from("u4char");