0becc89d4a
alignment of `byval` on x86 in the process.
Commit 88e4d2c291 from five years ago removed
support for alignment on indirectly-passed arguments because of problems with
the `i686-pc-windows-msvc` target. Unfortunately, the `memcpy` optimizations I
recently added to LLVM 16 depend on this to forward `memcpy`s. This commit
attempts to fix the problems with `byval` parameters on that target and now
correctly adds the `align` attribute.
The problem is summarized in [this comment] by @eddyb. Briefly, 32-bit x86 has
special alignment rules for `byval` parameters: for the most part, their
alignment is forced to 4. This is not well-documented anywhere but in the Clang
source. I looked at the logic in Clang `TargetInfo.cpp` and tried to replicate
it here. The relevant methods in that file are
`X86_32ABIInfo::getIndirectResult()` and
`X86_32ABIInfo::getTypeStackAlignInBytes()`. The `align` parameter attribute
for `byval` parameters in LLVM must match the platform ABI, or miscompilations
will occur. Note that this doesn't use the approach suggested by eddyb, because
I felt it was overkill to store the alignment in `on_stack` when special
handling is really only needed for 32-bit x86.
As a side effect, this should fix #80127, because it will make the `align`
parameter attribute for `byval` parameters match the platform ABI on LLVM
x86-64.
[this comment]: https://github.com/rust-lang/rust/pull/80822#issuecomment-829985417
291 lines
8.1 KiB
Rust
291 lines
8.1 KiB
Rust
// compile-flags: -O -C no-prepopulate-passes
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#![crate_type = "lib"]
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#![feature(dyn_star)]
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use std::mem::MaybeUninit;
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use std::num::NonZeroU64;
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use std::marker::PhantomPinned;
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use std::ptr::NonNull;
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pub struct S {
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_field: [i32; 8],
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}
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pub struct UnsafeInner {
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_field: std::cell::UnsafeCell<i16>,
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}
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pub struct NotUnpin {
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_field: i32,
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_marker: PhantomPinned,
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}
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pub enum MyBool {
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True,
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False,
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}
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// CHECK: noundef zeroext i1 @boolean(i1 noundef zeroext %x)
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#[no_mangle]
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pub fn boolean(x: bool) -> bool {
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x
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}
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// CHECK: i8 @maybeuninit_boolean(i8 %x)
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#[no_mangle]
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pub fn maybeuninit_boolean(x: MaybeUninit<bool>) -> MaybeUninit<bool> {
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x
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}
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// CHECK: noundef zeroext i1 @enum_bool(i1 noundef zeroext %x)
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#[no_mangle]
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pub fn enum_bool(x: MyBool) -> MyBool {
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x
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}
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// CHECK: i8 @maybeuninit_enum_bool(i8 %x)
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#[no_mangle]
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pub fn maybeuninit_enum_bool(x: MaybeUninit<MyBool>) -> MaybeUninit<MyBool> {
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x
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}
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// CHECK: noundef i32 @char(i32 noundef %x)
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#[no_mangle]
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pub fn char(x: char) -> char {
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x
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}
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// CHECK: i32 @maybeuninit_char(i32 %x)
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#[no_mangle]
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pub fn maybeuninit_char(x: MaybeUninit<char>) -> MaybeUninit<char> {
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x
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}
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// CHECK: noundef i64 @int(i64 noundef %x)
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#[no_mangle]
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pub fn int(x: u64) -> u64 {
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x
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}
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// CHECK: noundef i64 @nonzero_int(i64 noundef %x)
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#[no_mangle]
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pub fn nonzero_int(x: NonZeroU64) -> NonZeroU64 {
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x
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}
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// CHECK: noundef i64 @option_nonzero_int(i64 noundef %x)
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#[no_mangle]
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pub fn option_nonzero_int(x: Option<NonZeroU64>) -> Option<NonZeroU64> {
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x
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}
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// CHECK: @readonly_borrow({{i32\*|ptr}} noalias noundef readonly align 4 dereferenceable(4) %_1)
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// FIXME #25759 This should also have `nocapture`
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#[no_mangle]
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pub fn readonly_borrow(_: &i32) {
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}
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// CHECK: noundef align 4 dereferenceable(4) {{i32\*|ptr}} @readonly_borrow_ret()
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#[no_mangle]
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pub fn readonly_borrow_ret() -> &'static i32 {
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loop {}
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}
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// CHECK: @static_borrow({{i32\*|ptr}} noalias noundef readonly align 4 dereferenceable(4) %_1)
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// static borrow may be captured
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#[no_mangle]
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pub fn static_borrow(_: &'static i32) {
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}
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// CHECK: @named_borrow({{i32\*|ptr}} noalias noundef readonly align 4 dereferenceable(4) %_1)
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// borrow with named lifetime may be captured
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#[no_mangle]
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pub fn named_borrow<'r>(_: &'r i32) {
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}
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// CHECK: @unsafe_borrow({{i16\*|ptr}} noundef nonnull align 2 %_1)
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// unsafe interior means this isn't actually readonly and there may be aliases ...
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#[no_mangle]
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pub fn unsafe_borrow(_: &UnsafeInner) {
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}
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// CHECK: @mutable_unsafe_borrow({{i16\*|ptr}} noalias noundef align 2 dereferenceable(2) %_1)
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// ... unless this is a mutable borrow, those never alias
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#[no_mangle]
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pub fn mutable_unsafe_borrow(_: &mut UnsafeInner) {
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}
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// CHECK: @mutable_borrow({{i32\*|ptr}} noalias noundef align 4 dereferenceable(4) %_1)
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// FIXME #25759 This should also have `nocapture`
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#[no_mangle]
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pub fn mutable_borrow(_: &mut i32) {
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}
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// CHECK: noundef align 4 dereferenceable(4) {{i32\*|ptr}} @mutable_borrow_ret()
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#[no_mangle]
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pub fn mutable_borrow_ret() -> &'static mut i32 {
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loop {}
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}
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#[no_mangle]
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// CHECK: @mutable_notunpin_borrow({{i32\*|ptr}} noundef nonnull align 4 %_1)
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// This one is *not* `noalias` because it might be self-referential.
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// It is also not `dereferenceable` due to
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// <https://github.com/rust-lang/unsafe-code-guidelines/issues/381>.
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pub fn mutable_notunpin_borrow(_: &mut NotUnpin) {
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}
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// CHECK: @notunpin_borrow({{i32\*|ptr}} noalias noundef readonly align 4 dereferenceable(4) %_1)
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// But `&NotUnpin` behaves perfectly normal.
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#[no_mangle]
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pub fn notunpin_borrow(_: &NotUnpin) {
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}
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// CHECK: @indirect_struct({{%S\*|ptr}} noalias nocapture noundef readonly align 4 dereferenceable(32) %_1)
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#[no_mangle]
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pub fn indirect_struct(_: S) {
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}
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// CHECK: @borrowed_struct({{%S\*|ptr}} noalias noundef readonly align 4 dereferenceable(32) %_1)
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// FIXME #25759 This should also have `nocapture`
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#[no_mangle]
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pub fn borrowed_struct(_: &S) {
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}
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// CHECK: @option_borrow({{i32\*|ptr}} noalias noundef readonly align 4 dereferenceable_or_null(4) %x)
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#[no_mangle]
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pub fn option_borrow(x: Option<&i32>) {
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}
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// CHECK: @option_borrow_mut({{i32\*|ptr}} noalias noundef align 4 dereferenceable_or_null(4) %x)
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#[no_mangle]
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pub fn option_borrow_mut(x: Option<&mut i32>) {
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}
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// CHECK: @raw_struct({{%S\*|ptr}} noundef %_1)
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#[no_mangle]
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pub fn raw_struct(_: *const S) {
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}
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// CHECK: @raw_option_nonnull_struct({{i32\*|ptr}} noundef %_1)
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#[no_mangle]
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pub fn raw_option_nonnull_struct(_: Option<NonNull<S>>) {
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}
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// `Box` can get deallocated during execution of the function, so it should
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// not get `dereferenceable`.
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// CHECK: noundef nonnull align 4 {{i32\*|ptr}} @_box({{i32\*|ptr}} noalias noundef nonnull align 4 %x)
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#[no_mangle]
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pub fn _box(x: Box<i32>) -> Box<i32> {
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x
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}
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// CHECK: noundef nonnull align 4 {{i32\*|ptr}} @notunpin_box({{i32\*|ptr}} noundef nonnull align 4 %x)
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#[no_mangle]
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pub fn notunpin_box(x: Box<NotUnpin>) -> Box<NotUnpin> {
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x
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}
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// CHECK: @struct_return({{%S\*|ptr}} noalias nocapture noundef sret(%S) align 4 dereferenceable(32){{( %_0)?}})
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#[no_mangle]
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pub fn struct_return() -> S {
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S {
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_field: [0, 0, 0, 0, 0, 0, 0, 0]
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}
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}
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// Hack to get the correct size for the length part in slices
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// CHECK: @helper([[USIZE:i[0-9]+]] noundef %_1)
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#[no_mangle]
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pub fn helper(_: usize) {
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}
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// CHECK: @slice({{\[0 x i8\]\*|ptr}} noalias noundef nonnull readonly align 1 %_1.0, [[USIZE]] noundef %_1.1)
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// FIXME #25759 This should also have `nocapture`
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#[no_mangle]
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pub fn slice(_: &[u8]) {
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}
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// CHECK: @mutable_slice({{\[0 x i8\]\*|ptr}} noalias noundef nonnull align 1 %_1.0, [[USIZE]] noundef %_1.1)
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// FIXME #25759 This should also have `nocapture`
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#[no_mangle]
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pub fn mutable_slice(_: &mut [u8]) {
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}
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// CHECK: @unsafe_slice({{\[0 x i16\]\*|ptr}} noundef nonnull align 2 %_1.0, [[USIZE]] noundef %_1.1)
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// unsafe interior means this isn't actually readonly and there may be aliases ...
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#[no_mangle]
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pub fn unsafe_slice(_: &[UnsafeInner]) {
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}
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// CHECK: @raw_slice({{\[0 x i8\]\*|ptr}} noundef %_1.0, [[USIZE]] noundef %_1.1)
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#[no_mangle]
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pub fn raw_slice(_: *const [u8]) {
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}
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// CHECK: @str({{\[0 x i8\]\*|ptr}} noalias noundef nonnull readonly align 1 %_1.0, [[USIZE]] noundef %_1.1)
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// FIXME #25759 This should also have `nocapture`
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#[no_mangle]
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pub fn str(_: &[u8]) {
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}
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// CHECK: @trait_borrow({{\{\}\*|ptr}} noundef nonnull align 1 %_1.0, {{.+}} noalias noundef readonly align {{.*}} dereferenceable({{.*}}) %_1.1)
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// FIXME #25759 This should also have `nocapture`
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#[no_mangle]
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pub fn trait_borrow(_: &dyn Drop) {
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}
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// CHECK: @option_trait_borrow({{i8\*|ptr}} noundef align 1 %x.0, {{i8\*|ptr}} %x.1)
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#[no_mangle]
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pub fn option_trait_borrow(x: Option<&dyn Drop>) {
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}
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// CHECK: @option_trait_borrow_mut({{i8\*|ptr}} noundef align 1 %x.0, {{i8\*|ptr}} %x.1)
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#[no_mangle]
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pub fn option_trait_borrow_mut(x: Option<&mut dyn Drop>) {
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}
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// CHECK: @trait_raw({{\{\}\*|ptr}} noundef %_1.0, {{.+}} noalias noundef readonly align {{.*}} dereferenceable({{.*}}) %_1.1)
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#[no_mangle]
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pub fn trait_raw(_: *const dyn Drop) {
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}
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// CHECK: @trait_box({{\{\}\*|ptr}} noalias noundef nonnull align 1{{( %0)?}}, {{.+}} noalias noundef readonly align {{.*}} dereferenceable({{.*}}){{( %1)?}})
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#[no_mangle]
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pub fn trait_box(_: Box<dyn Drop + Unpin>) {
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}
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// CHECK: { {{i8\*|ptr}}, {{i8\*|ptr}} } @trait_option({{i8\*|ptr}} noalias noundef align 1 %x.0, {{i8\*|ptr}} %x.1)
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#[no_mangle]
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pub fn trait_option(x: Option<Box<dyn Drop + Unpin>>) -> Option<Box<dyn Drop + Unpin>> {
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x
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}
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// CHECK: { {{\[0 x i16\]\*|ptr}}, [[USIZE]] } @return_slice({{\[0 x i16\]\*|ptr}} noalias noundef nonnull readonly align 2 %x.0, [[USIZE]] noundef %x.1)
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#[no_mangle]
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pub fn return_slice(x: &[u16]) -> &[u16] {
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x
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}
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// CHECK: { i16, i16 } @enum_id_1(i16 noundef %x.0, i16 %x.1)
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#[no_mangle]
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pub fn enum_id_1(x: Option<Result<u16, u16>>) -> Option<Result<u16, u16>> {
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x
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}
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// CHECK: { i8, i8 } @enum_id_2(i1 noundef zeroext %x.0, i8 %x.1)
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#[no_mangle]
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pub fn enum_id_2(x: Option<u8>) -> Option<u8> {
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x
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}
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// CHECK: { {{\{\}\*|ptr}}, {{.+}} } @dyn_star({{\{\}\*|ptr}} noundef %x.0, {{.+}} noalias noundef readonly align {{.*}} dereferenceable({{.*}}) %x.1)
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// Expect an ABI something like `{ {}*, [3 x i64]* }`, but that's hard to match on generically,
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// so do like the `trait_box` test and just match on `{{.+}}` for the vtable.
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#[no_mangle]
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pub fn dyn_star(x: dyn* Drop) -> dyn* Drop {
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x
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}
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