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

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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
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38
compiler/rustc_codegen_llvm/src/builder.rs
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@ -477,6 +477,8 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'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 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'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 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'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 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'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 @@ impl<'a, 'll, 'tcx> Builder<'a, 'll, 'tcx> {
}
}
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(