Do not depend on mono anymore

Author: Sa4dUs

compiler/rustc_codegen_llvm/src/builder/autodiff.rs

@@ -3,7 +3,8 @@ use std::ptr;
 use rustc_ast::expand::autodiff_attrs::{AutoDiffAttrs, DiffActivity, DiffMode};
 use rustc_codegen_ssa::common::TypeKind;
 use rustc_codegen_ssa::traits::{BaseTypeCodegenMethods, BuilderMethods};
-use rustc_middle::bug;
+use rustc_middle::{bug, ty};
+use rustc_middle::ty::{PseudoCanonicalInput, Ty, TyCtxt, TypingEnv};
 use tracing::debug;
 
 use crate::builder::{Builder, PlaceRef, UNNAMED};
@@ -14,6 +15,82 @@ use crate::llvm::{Metadata, True, Type};
 use crate::value::Value;
 use crate::{attributes, llvm};
 
+pub(crate) 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);
+    }
+}
+
 // When we call the `__enzyme_autodiff` or `__enzyme_fwddiff` function, we need to pass all the
 // original inputs, as well as metadata and the additional shadow arguments.
 // This function matches the arguments from the outer function to the inner enzyme call.

compiler/rustc_codegen_llvm/src/intrinsic.rs

@@ -3,6 +3,7 @@ use std::cmp::Ordering;
 
 use rustc_abi::{Align, BackendRepr, ExternAbi, Float, HasDataLayout, Primitive, Size};
 use rustc_codegen_ssa::base::{compare_simd_types, wants_msvc_seh, wants_wasm_eh};
+use rustc_codegen_ssa::codegen_attrs::autodiff_attrs;
 use rustc_codegen_ssa::common::{IntPredicate, TypeKind};
 use rustc_codegen_ssa::errors::{ExpectedPointerMutability, InvalidMonomorphization};
 use rustc_codegen_ssa::mir::operand::{OperandRef, OperandValue};
@@ -12,7 +13,7 @@ use rustc_hir::def_id::LOCAL_CRATE;
 use rustc_hir::{self as hir};
 use rustc_middle::mir::BinOp;
 use rustc_middle::ty::layout::{FnAbiOf, HasTyCtxt, HasTypingEnv, LayoutOf};
-use rustc_middle::ty::{self, GenericArgsRef, Instance, Ty, TyCtxt};
+use rustc_middle::ty::{self, GenericArgsRef, Instance, Ty, TyCtxt, TypingEnv};
 use rustc_middle::{bug, span_bug};
 use rustc_span::{Span, Symbol, sym};
 use rustc_symbol_mangling::{mangle_internal_symbol, symbol_name_for_instance_in_crate};
@@ -21,7 +22,7 @@ use tracing::debug;
 
 use crate::abi::FnAbiLlvmExt;
 use crate::builder::Builder;
-use crate::builder::autodiff::generate_enzyme_call;
+use crate::builder::autodiff::{adjust_activity_to_abi, generate_enzyme_call};
 use crate::context::CodegenCx;
 use crate::llvm::{self, Metadata};
 use crate::type_::Type;
@@ -1166,14 +1167,14 @@ fn codegen_enzyme_autodiff<'ll, 'tcx>(
         Instance::try_resolve(tcx, bx.cx.typing_env(), *diff_id, diff_args).unwrap().unwrap();
     let diff_symbol = symbol_name_for_instance_in_crate(tcx, fn_diff.clone(), LOCAL_CRATE);
 
-    // TODO(Sa4dUs): Store autodiff items in a single pass and just get them here
-    // in a O(1) step
-    let diff_attrs = tcx
-        .collect_and_partition_mono_items(())
-        .autodiff_items
-        .iter()
-        .find(|item| item.target == diff_symbol);
-    let Some(diff_attrs) = diff_attrs else { bug!("could not find autodiff attrs") };
+    let diff_attrs = autodiff_attrs(tcx, fn_diff.def_id());
+    let Some(mut diff_attrs) = diff_attrs else { bug!("could not find autodiff attrs") };
+
+    adjust_activity_to_abi(
+        tcx,
+        fn_source.ty(tcx, TypingEnv::fully_monomorphized()),
+        &mut diff_attrs.input_activity,
+    );
 
     // Build body
     generate_enzyme_call(
@@ -1183,7 +1184,7 @@ fn codegen_enzyme_autodiff<'ll, 'tcx>(
         &diff_symbol,
         llret_ty,
         &val_arr,
-        diff_attrs.attrs.clone(),
+        diff_attrs.clone(),
         result,
     );
 }