mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Auto merge of #94159 - erikdesjardins:align-load, r=nikic

Browse Source 
Add !align metadata on loads of &/&mut/Box

Note that this refers to the alignment of what the loaded value points
to, _not_ the alignment of the loaded value itself.

r? `@ghost` (blocked on #94158)
This commit is contained in:
bors 2022-03-04 08:14:31 +00:00
commit 62ff2bcf94
3 changed files with 67 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
compiler/rustc_codegen_llvm/src/builder.rs
View File

@ -477,6 +477,8 @@ fn scalar_load_metadata<'a, 'll, 'tcx>(
bx: &mut Builder<'a, 'll, 'tcx>,
load: &'ll Value,
scalar: abi::Scalar,
layout: TyAndLayout<'tcx>,
offset: Size,
) {
if !scalar.is_always_valid(bx) {
bx.noundef_metadata(load);
@ -488,10 +490,18 @@ fn scalar_load_metadata<'a, 'll, 'tcx>(
bx.range_metadata(load, scalar.valid_range);
}
}
abi::Pointer if !scalar.valid_range.contains(0) => {
bx.nonnull_metadata(load);
abi::Pointer => {
if !scalar.valid_range.contains(0) {
bx.nonnull_metadata(load);
}
if let Some(pointee) = layout.pointee_info_at(bx, offset) {
if let Some(_) = pointee.safe {
bx.align_metadata(load, pointee.align);
}
}
}
_ => {}
abi::F32 | abi::F64 => {}
}
}
@ -509,7 +519,7 @@ fn scalar_load_metadata<'a, 'll, 'tcx>(
let llval = const_llval.unwrap_or_else(|| {
let load = self.load(place.layout.llvm_type(self), place.llval, place.align);
if let abi::Abi::Scalar(scalar) = place.layout.abi {
scalar_load_metadata(self, load, scalar);
scalar_load_metadata(self, load, scalar, place.layout, Size::ZERO);
}
load
});
@ -518,17 +528,17 @@ fn scalar_load_metadata<'a, 'll, 'tcx>(
let b_offset = a.value.size(self).align_to(b.value.align(self).abi);
let pair_ty = place.layout.llvm_type(self);
let mut load = |i, scalar: abi::Scalar, align| {
let mut load = |i, scalar: abi::Scalar, layout, align, offset| {
let llptr = self.struct_gep(pair_ty, place.llval, i as u64);
let llty = place.layout.scalar_pair_element_llvm_type(self, i, false);
let load = self.load(llty, llptr, align);
scalar_load_metadata(self, load, scalar);
scalar_load_metadata(self, load, scalar, layout, offset);
self.to_immediate_scalar(load, scalar)
};
OperandValue::Pair(
load(0, a, place.align),
load(1, b, place.align.restrict_for_offset(b_offset)),
load(0, a, place.layout, place.align, Size::ZERO),
load(1, b, place.layout, place.align.restrict_for_offset(b_offset), b_offset),
)
} else {
OperandValue::Ref(place.llval, None, place.align)
@ -1208,6 +1218,18 @@ fn position_at_start(&mut self, llbb: &'ll BasicBlock) {
}
}
fn align_metadata(&mut self, load: &'ll Value, align: Align) {
unsafe {
let v = [self.cx.const_u64(align.bytes())];
llvm::LLVMSetMetadata(
load,
llvm::MD_align as c_uint,
llvm::LLVMMDNodeInContext(self.cx.llcx, v.as_ptr(), v.len() as c_uint),
);
}
}
fn noundef_metadata(&mut self, load: &'ll Value) {
unsafe {
llvm::LLVMSetMetadata(

1
compiler/rustc_codegen_llvm/src/llvm/ffi.rs
View File

@ -441,6 +441,7 @@ pub enum MetadataType {
MD_nontemporal = 9,
MD_mem_parallel_loop_access = 10,
MD_nonnull = 11,
MD_align = 17,
MD_type = 19,
MD_noundef = 29,
}

44
src/test/codegen/loads.rs
View File

@ -18,21 +18,47 @@ pub enum MyBool {
False,
}
#[repr(align(16))]
pub struct Align16(u128);
// CHECK: @ptr_alignment_helper({}** {{.*}}align [[PTR_ALIGNMENT:[0-9]+]]
#[no_mangle]
pub fn ptr_alignment_helper(x: &&()) {}
// CHECK-LABEL: @load_ref
#[no_mangle]
pub fn load_ref<'a>(x: &&'a i32) -> &'a i32 {
// Alignment of a reference itself is target dependent, so just match any alignment:
// the main thing we care about here is !nonnull and !noundef.
// CHECK: load i32*, i32** %x, align {{[0-9]+}}, !nonnull !{{[0-9]+}}, !noundef !{{[0-9]+}}
// CHECK: load i32*, i32** %x, align [[PTR_ALIGNMENT]], !nonnull !{{[0-9]+}}, !align ![[ALIGN_4_META:[0-9]+]], !noundef !{{[0-9]+}}
*x
}
// CHECK-LABEL: @load_ref_higher_alignment
#[no_mangle]
pub fn load_ref_higher_alignment<'a>(x: &&'a Align16) -> &'a Align16 {
// CHECK: load {{%Align16|i128}}*, {{%Align16|i128}}** %x, align [[PTR_ALIGNMENT]], !nonnull !{{[0-9]+}}, !align ![[ALIGN_16_META:[0-9]+]], !noundef !{{[0-9]+}}
*x
}
// CHECK-LABEL: @load_scalar_pair
#[no_mangle]
pub fn load_scalar_pair<'a>(x: &(&'a i32, &'a Align16)) -> (&'a i32, &'a Align16) {
// CHECK: load i32*, i32** %{{.+}}, align [[PTR_ALIGNMENT]], !nonnull !{{[0-9]+}}, !align ![[ALIGN_4_META]], !noundef !{{[0-9]+}}
// CHECK: load i64*, i64** %{{.+}}, align [[PTR_ALIGNMENT]], !nonnull !{{[0-9]+}}, !align ![[ALIGN_16_META]], !noundef !{{[0-9]+}}
*x
}
// CHECK-LABEL: @load_raw_pointer
#[no_mangle]
pub fn load_raw_pointer<'a>(x: &*const i32) -> *const i32 {
// loaded raw pointer should not have !nonnull, !align, or !noundef metadata
// CHECK: load i32*, i32** %x, align [[PTR_ALIGNMENT]]{{$}}
*x
}
// CHECK-LABEL: @load_box
#[no_mangle]
pub fn load_box<'a>(x: Box<Box<i32>>) -> Box<i32> {
// Alignment of a box itself is target dependent, so just match any alignment:
// the main thing we care about here is !nonnull and !noundef.
// CHECK: load i32*, i32** %x, align {{[0-9]+}}, !nonnull !{{[0-9]+}}, !noundef !{{[0-9]+}}
// CHECK: load i32*, i32** %x, align [[PTR_ALIGNMENT]], !nonnull !{{[0-9]+}}, !align ![[ALIGN_4_META]], !noundef !{{[0-9]+}}
*x
}
@ -120,5 +146,7 @@ pub fn small_struct_alignment(x: Bytes) -> Bytes {
x
}
// CHECK: ![[BOOL_RANGE]] = !{i8 0, i8 2}
// CHECK: ![[NONZEROU16_RANGE]] = !{i16 1, i16 0}
// CHECK-DAG: ![[BOOL_RANGE]] = !{i8 0, i8 2}
// CHECK-DAG: ![[NONZEROU16_RANGE]] = !{i16 1, i16 0}
// CHECK-DAG: ![[ALIGN_4_META]] = !{i64 4}
// CHECK-DAG: ![[ALIGN_16_META]] = !{i64 16}