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Rollup merge of rust-lang#137363 - workingjubilee:untangle-x86-abi-impl, r=jieyouxu compiler: factor Windows x86-32 ABI impl into its own file While it shares more than zero code with the SysV x86-32 ABI impl, there is no particular reason to organize wildly different ABIs using if-else in the same function.
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,81 @@ | ||
| use rustc_abi::{Align, HasDataLayout, Reg, TyAbiInterface}; | ||
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| use crate::callconv::FnAbi; | ||
| use crate::spec::HasTargetSpec; | ||
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| pub(crate) fn compute_abi_info<'a, Ty, C>( | ||
| cx: &C, | ||
| fn_abi: &mut FnAbi<'a, Ty>, | ||
| opts: super::x86::X86Options, | ||
| ) where | ||
| Ty: TyAbiInterface<'a, C> + Copy, | ||
| C: HasDataLayout + HasTargetSpec, | ||
| { | ||
| if !fn_abi.ret.is_ignore() { | ||
| if fn_abi.ret.layout.is_aggregate() && fn_abi.ret.layout.is_sized() { | ||
| // Returning a structure. Most often, this will use | ||
| // a hidden first argument. On some platforms, though, | ||
| // small structs are returned as integers. | ||
| // | ||
| // Some links: | ||
| // https://www.angelcode.com/dev/callconv/callconv.html | ||
| // Clang's ABI handling is in lib/CodeGen/TargetInfo.cpp | ||
| let t = cx.target_spec(); | ||
| // MSVC does not special-case 1-element float aggregates, unlike others. | ||
| // GCC used to apply the SysV rule here, breaking windows-gnu's ABI, but was fixed: | ||
| // - reported in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82028 | ||
| // - fixed in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85667 | ||
| if t.abi_return_struct_as_int || opts.reg_struct_return { | ||
| match fn_abi.ret.layout.size.bytes() { | ||
| 1 => fn_abi.ret.cast_to(Reg::i8()), | ||
| 2 => fn_abi.ret.cast_to(Reg::i16()), | ||
| 4 => fn_abi.ret.cast_to(Reg::i32()), | ||
| 8 => fn_abi.ret.cast_to(Reg::i64()), | ||
| _ => fn_abi.ret.make_indirect(), | ||
| } | ||
| } else { | ||
| fn_abi.ret.make_indirect(); | ||
| } | ||
| } else { | ||
| fn_abi.ret.extend_integer_width_to(32); | ||
| } | ||
| } | ||
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| for arg in fn_abi.args.iter_mut() { | ||
| if arg.is_ignore() || !arg.layout.is_sized() { | ||
| continue; | ||
| } | ||
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| // FIXME: MSVC 2015+ will pass the first 3 vector arguments in [XYZ]MM0-2 | ||
| // See https://reviews.llvm.org/D72114 for Clang behavior | ||
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| let align_4 = Align::from_bytes(4).unwrap(); | ||
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| if arg.layout.is_adt() | ||
| && let Some(max_repr_align) = arg.layout.max_repr_align | ||
| && max_repr_align > align_4 | ||
| { | ||
| // MSVC has special rules for overaligned arguments: https://reviews.llvm.org/D72114. | ||
| // Summarized here: | ||
| // - Arguments with _requested_ alignment > 4 are passed indirectly. | ||
| // - For backwards compatibility, arguments with natural alignment > 4 are still passed | ||
| // on stack (via `byval`). For example, this includes `double`, `int64_t`, | ||
| // and structs containing them, provided they lack an explicit alignment attribute. | ||
| assert!( | ||
| arg.layout.align.abi >= max_repr_align, | ||
| "abi alignment {:?} less than requested alignment {max_repr_align:?}", | ||
| arg.layout.align.abi, | ||
| ); | ||
| arg.make_indirect(); | ||
| } else if arg.layout.is_aggregate() { | ||
| // Alignment of the `byval` argument. | ||
| // The rules can be found in `X86_32ABIInfo::getTypeStackAlignInBytes` in Clang's `TargetInfo.cpp`. | ||
| let byval_align = align_4; | ||
| arg.pass_by_stack_offset(Some(byval_align)); | ||
| } else { | ||
| arg.extend_integer_width_to(32); | ||
| } | ||
| } | ||
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| super::x86::fill_inregs(cx, fn_abi, opts, false); | ||
| } |