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use rustc_ast::expand::autodiff_attrs::{AutoDiffItem, DiffActivity};
use rustc_hir::def_id::LOCAL_CRATE;
use rustc_middle::bug;
use rustc_middle::mir::mono::MonoItem;
use rustc_middle::ty::{self, Instance, PseudoCanonicalInput, Ty, TyCtxt, TypingEnv};
use rustc_symbol_mangling::symbol_name_for_instance_in_crate;
use tracing::{debug, trace};
use crate::partitioning::UsageMap;
fn adjust_activity_to_abi<'tcx>(tcx: TyCtxt<'tcx>, fn_ty: Ty<'tcx>, da: &mut Vec<DiffActivity>) {
if !matches!(fn_ty.kind(), ty::FnDef(..)) {
bug!("expected fn def for autodiff, got {:?}", fn_ty);
}
// We don't actually pass the types back into the type system.
// All we do is decide how to handle the arguments.
let sig = fn_ty.fn_sig(tcx).skip_binder();
let mut new_activities = vec![];
let mut new_positions = vec![];
for (i, ty) in sig.inputs().iter().enumerate() {
if let Some(inner_ty) = ty.builtin_deref(true) {
if inner_ty.is_slice() {
// Now we need to figure out the size of each slice element in memory to allow
// safety checks and usability improvements in the backend.
let sty = match inner_ty.builtin_index() {
Some(sty) => sty,
None => {
panic!("slice element type unknown");
}
};
let pci = PseudoCanonicalInput {
typing_env: TypingEnv::fully_monomorphized(),
value: sty,
};
let layout = tcx.layout_of(pci);
let elem_size = match layout {
Ok(layout) => layout.size,
Err(_) => {
bug!("autodiff failed to compute slice element size");
}
};
let elem_size: u32 = elem_size.bytes() as u32;
// We know that the length will be passed as extra arg.
if !da.is_empty() {
// We are looking at a slice. The length of that slice will become an
// extra integer on llvm level. Integers are always const.
// However, if the slice get's duplicated, we want to know to later check the
// size. So we mark the new size argument as FakeActivitySize.
// There is one FakeActivitySize per slice, so for convenience we store the
// slice element size in bytes in it. We will use the size in the backend.
let activity = match da[i] {
DiffActivity::DualOnly
| DiffActivity::Dual
| DiffActivity::Dualv
| DiffActivity::DuplicatedOnly
| DiffActivity::Duplicated => {
DiffActivity::FakeActivitySize(Some(elem_size))
}
DiffActivity::Const => DiffActivity::Const,
_ => bug!("unexpected activity for ptr/ref"),
};
new_activities.push(activity);
new_positions.push(i + 1);
}
continue;
}
}
}
// now add the extra activities coming from slices
// Reverse order to not invalidate the indices
for _ in 0..new_activities.len() {
let pos = new_positions.pop().unwrap();
let activity = new_activities.pop().unwrap();
da.insert(pos, activity);
}
}
pub(crate) fn find_autodiff_source_functions<'tcx>(
tcx: TyCtxt<'tcx>,
usage_map: &UsageMap<'tcx>,
autodiff_mono_items: Vec<(&MonoItem<'tcx>, &Instance<'tcx>)>,
) -> Vec<AutoDiffItem> {
let mut autodiff_items: Vec<AutoDiffItem> = vec![];
for (item, instance) in autodiff_mono_items {
let target_id = instance.def_id();
let cg_fn_attr = &tcx.codegen_fn_attrs(target_id).autodiff_item;
let Some(target_attrs) = cg_fn_attr else {
continue;
};
let mut input_activities: Vec<DiffActivity> = target_attrs.input_activity.clone();
if target_attrs.is_source() {
trace!("source found: {:?}", target_id);
}
if !target_attrs.apply_autodiff() {
continue;
}
let target_symbol = symbol_name_for_instance_in_crate(tcx, instance.clone(), LOCAL_CRATE);
let source =
usage_map.used_map.get(&item).unwrap().into_iter().find_map(|item| match *item {
MonoItem::Fn(ref instance_s) => {
let source_id = instance_s.def_id();
if let Some(ad) = &tcx.codegen_fn_attrs(source_id).autodiff_item
&& ad.is_active()
{
return Some(instance_s);
}
None
}
_ => None,
});
let inst = match source {
Some(source) => source,
None => continue,
};
debug!("source_id: {:?}", inst.def_id());
let fn_ty = inst.ty(tcx, ty::TypingEnv::fully_monomorphized());
assert!(fn_ty.is_fn());
adjust_activity_to_abi(tcx, fn_ty, &mut input_activities);
let symb = symbol_name_for_instance_in_crate(tcx, inst.clone(), LOCAL_CRATE);
let mut new_target_attrs = target_attrs.clone();
new_target_attrs.input_activity = input_activities;
let itm = new_target_attrs.into_item(symb, target_symbol);
autodiff_items.push(itm);
}
if !autodiff_items.is_empty() {
trace!("AUTODIFF ITEMS EXIST");
for item in &mut *autodiff_items {
trace!("{}", &item);
}
}
autodiff_items
}
|
