Remove dead code

Author: Sa4dUs

Cargo.lock

@@ -4217,7 +4217,6 @@ name = "rustc_monomorphize"
 version = "0.0.0"
 dependencies = [
  "rustc_abi",
- "rustc_ast",
  "rustc_attr_data_structures",
  "rustc_data_structures",
  "rustc_errors",
@@ -4227,7 +4226,6 @@ dependencies = [
  "rustc_middle",
  "rustc_session",
  "rustc_span",
- "rustc_symbol_mangling",
  "rustc_target",
  "serde",
  "serde_json",

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -8,7 +8,6 @@ use std::{fs, io, mem, str, thread};
 
 use rustc_abi::Size;
 use rustc_ast::attr;
-use rustc_ast::expand::autodiff_attrs::AutoDiffItem;
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::jobserver::{self, Acquired};
 use rustc_data_structures::memmap::Mmap;
@@ -39,7 +38,7 @@ use tracing::debug;
 use super::link::{self, ensure_removed};
 use super::lto::{self, SerializedModule};
 use crate::back::lto::check_lto_allowed;
-use crate::errors::{AutodiffWithoutLto, ErrorCreatingRemarkDir};
+use crate::errors::ErrorCreatingRemarkDir;
 use crate::traits::*;
 use crate::{
     CachedModuleCodegen, CodegenResults, CompiledModule, CrateInfo, ModuleCodegen, ModuleKind,
@@ -455,7 +454,6 @@ pub(crate) fn start_async_codegen<B: ExtraBackendMethods>(
     backend: B,
     tcx: TyCtxt<'_>,
     target_cpu: String,
-    autodiff_items: &[AutoDiffItem],
 ) -> OngoingCodegen<B> {
     let (coordinator_send, coordinator_receive) = channel();
 
@@ -474,7 +472,6 @@ pub(crate) fn start_async_codegen<B: ExtraBackendMethods>(
         backend.clone(),
         tcx,
         &crate_info,
-        autodiff_items,
         shared_emitter,
         codegen_worker_send,
         coordinator_receive,
@@ -729,7 +726,6 @@ pub(crate) enum WorkItem<B: WriteBackendMethods> {
         each_linked_rlib_for_lto: Vec<PathBuf>,
         needs_fat_lto: Vec<FatLtoInput<B>>,
         import_only_modules: Vec<(SerializedModule<B::ModuleBuffer>, WorkProduct)>,
-        autodiff: Vec<AutoDiffItem>,
     },
     /// Performs thin-LTO on the given module.
     ThinLto(lto::ThinModule<B>),
@@ -1003,7 +999,6 @@ fn execute_fat_lto_work_item<B: ExtraBackendMethods>(
     each_linked_rlib_for_lto: &[PathBuf],
     mut needs_fat_lto: Vec<FatLtoInput<B>>,
     import_only_modules: Vec<(SerializedModule<B::ModuleBuffer>, WorkProduct)>,
-    autodiff: Vec<AutoDiffItem>,
     module_config: &ModuleConfig,
 ) -> Result<WorkItemResult<B>, FatalError> {
     for (module, wp) in import_only_modules {
@@ -1015,7 +1010,6 @@ fn execute_fat_lto_work_item<B: ExtraBackendMethods>(
         exported_symbols_for_lto,
         each_linked_rlib_for_lto,
         needs_fat_lto,
-        autodiff,
     )?;
     let module = B::codegen(cgcx, module, module_config)?;
     Ok(WorkItemResult::Finished(module))
@@ -1119,7 +1113,6 @@ fn start_executing_work<B: ExtraBackendMethods>(
     backend: B,
     tcx: TyCtxt<'_>,
     crate_info: &CrateInfo,
-    autodiff_items: &[AutoDiffItem],
     shared_emitter: SharedEmitter,
     codegen_worker_send: Sender<CguMessage>,
     coordinator_receive: Receiver<Box<dyn Any + Send>>,
@@ -1129,7 +1122,6 @@ fn start_executing_work<B: ExtraBackendMethods>(
 ) -> thread::JoinHandle<Result<CompiledModules, ()>> {
     let coordinator_send = tx_to_llvm_workers;
     let sess = tcx.sess;
-    let autodiff_items = autodiff_items.to_vec();
 
     let mut each_linked_rlib_for_lto = Vec::new();
     let mut each_linked_rlib_file_for_lto = Vec::new();
@@ -1464,19 +1456,13 @@ fn start_executing_work<B: ExtraBackendMethods>(
                                 each_linked_rlib_for_lto: each_linked_rlib_file_for_lto,
                                 needs_fat_lto,
                                 import_only_modules,
-                                autodiff: autodiff_items.clone(),
                             },
                             0,
                         ));
                         if cgcx.parallel {
                             helper.request_token();
                         }
                     } else {
-                        if !autodiff_items.is_empty() {
-                            let dcx = cgcx.create_dcx();
-                            dcx.handle().emit_fatal(AutodiffWithoutLto {});
-                        }
-
                         for (work, cost) in generate_thin_lto_work(
                             &cgcx,
                             &exported_symbols_for_lto,
@@ -1827,7 +1813,6 @@ fn spawn_work<'a, B: ExtraBackendMethods>(
                     each_linked_rlib_for_lto,
                     needs_fat_lto,
                     import_only_modules,
-                    autodiff,
                 } => {
                     let _timer = cgcx
                         .prof
@@ -1838,7 +1823,6 @@ fn spawn_work<'a, B: ExtraBackendMethods>(
                         &each_linked_rlib_for_lto,
                         needs_fat_lto,
                         import_only_modules,
-                        autodiff,
                         module_config,
                     )
                 }

compiler/rustc_codegen_ssa/src/base.rs

@@ -647,7 +647,7 @@ pub fn codegen_crate<B: ExtraBackendMethods>(
 ) -> OngoingCodegen<B> {
     // Skip crate items and just output metadata in -Z no-codegen mode.
     if tcx.sess.opts.unstable_opts.no_codegen || !tcx.sess.opts.output_types.should_codegen() {
-        let ongoing_codegen = start_async_codegen(backend, tcx, target_cpu, &[]);
+        let ongoing_codegen = start_async_codegen(backend, tcx, target_cpu);
 
         ongoing_codegen.codegen_finished(tcx);
 
@@ -665,8 +665,7 @@ pub fn codegen_crate<B: ExtraBackendMethods>(
 
     // Run the monomorphization collector and partition the collected items into
     // codegen units.
-    let MonoItemPartitions { codegen_units, autodiff_items, .. } =
-        tcx.collect_and_partition_mono_items(());
+    let MonoItemPartitions { codegen_units, .. } = tcx.collect_and_partition_mono_items(());
 
     // Force all codegen_unit queries so they are already either red or green
     // when compile_codegen_unit accesses them. We are not able to re-execute
@@ -679,7 +678,7 @@ pub fn codegen_crate<B: ExtraBackendMethods>(
         }
     }
 
-    let ongoing_codegen = start_async_codegen(backend.clone(), tcx, target_cpu, autodiff_items);
+    let ongoing_codegen = start_async_codegen(backend.clone(), tcx, target_cpu);
 
     // Codegen an allocator shim, if necessary.
     if let Some(kind) = allocator_kind_for_codegen(tcx) {

compiler/rustc_codegen_ssa/src/traits/write.rs

@@ -1,6 +1,5 @@
 use std::path::PathBuf;
 
-use rustc_ast::expand::autodiff_attrs::AutoDiffItem;
 use rustc_errors::{DiagCtxtHandle, FatalError};
 use rustc_middle::dep_graph::WorkProduct;
 
@@ -29,7 +28,6 @@ pub trait WriteBackendMethods: Clone + 'static {
         exported_symbols_for_lto: &[String],
         each_linked_rlib_for_lto: &[PathBuf],
         modules: Vec<FatLtoInput<Self>>,
-        diff_fncs: Vec<AutoDiffItem>,
     ) -> Result<ModuleCodegen<Self::Module>, FatalError>;
     /// Performs thin LTO by performing necessary global analysis and returning two
     /// lists, one of the modules that need optimization and another for modules that

compiler/rustc_middle/src/mir/mono.rs

@@ -2,7 +2,6 @@ use std::borrow::Cow;
 use std::fmt;
 use std::hash::Hash;
 
-use rustc_ast::expand::autodiff_attrs::AutoDiffItem;
 use rustc_attr_data_structures::InlineAttr;
 use rustc_data_structures::base_n::{BaseNString, CASE_INSENSITIVE, ToBaseN};
 use rustc_data_structures::fingerprint::Fingerprint;
@@ -337,7 +336,6 @@ impl ToStableHashKey<StableHashingContext<'_>> for MonoItem<'_> {
 pub struct MonoItemPartitions<'tcx> {
     pub codegen_units: &'tcx [CodegenUnit<'tcx>],
     pub all_mono_items: &'tcx DefIdSet,
-    pub autodiff_items: &'tcx [AutoDiffItem],
 }
 
 #[derive(Debug, HashStable)]

compiler/rustc_monomorphize/Cargo.toml

@@ -6,7 +6,6 @@ edition = "2024"
 [dependencies]
 # tidy-alphabetical-start
 rustc_abi = { path = "../rustc_abi" }
-rustc_ast = { path = "../rustc_ast" }
 rustc_attr_data_structures = { path = "../rustc_attr_data_structures" }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_errors = { path = "../rustc_errors" }
@@ -16,7 +15,6 @@ rustc_macros = { path = "../rustc_macros" }
 rustc_middle = { path = "../rustc_middle" }
 rustc_session = { path = "../rustc_session" }
 rustc_span = { path = "../rustc_span" }
-rustc_symbol_mangling = { path = "../rustc_symbol_mangling" }
 rustc_target = { path = "../rustc_target" }
 serde = "1"
 serde_json = "1"

compiler/rustc_monomorphize/src/collector/autodiff.rs

@@ -18,7 +18,6 @@ pub(crate) fn collect_enzyme_autodiff_fn<'tcx>(
     };
 
     collect_autodiff_fn_from_arg(instance.args[0], tcx, output);
-    collect_autodiff_fn_from_arg(instance.args[1], tcx, output);
 }
 
 fn collect_autodiff_fn_from_arg<'tcx>(

compiler/rustc_monomorphize/src/partitioning.rs

@@ -92,8 +92,6 @@
 //! source-level module, functions from the same module will be available for
 //! inlining, even when they are not marked `#[inline]`.
 
-mod autodiff;
-
 use std::cmp;
 use std::collections::hash_map::Entry;
 use std::fs::{self, File};
@@ -251,17 +249,7 @@ where
             always_export_generics,
         );
 
-        // We can't differentiate a function that got inlined.
-        let autodiff_active = cfg!(llvm_enzyme)
-            && matches!(mono_item, MonoItem::Fn(_))
-            && cx
-                .tcx
-                .codegen_fn_attrs(mono_item.def_id())
-                .autodiff_item
-                .as_ref()
-                .is_some_and(|ad| ad.is_active());
-
-        if !autodiff_active && visibility == Visibility::Hidden && can_be_internalized {
+        if visibility == Visibility::Hidden && can_be_internalized {
             internalization_candidates.insert(mono_item);
         }
         let size_estimate = mono_item.size_estimate(cx.tcx);
@@ -1156,27 +1144,15 @@ fn collect_and_partition_mono_items(tcx: TyCtxt<'_>, (): ()) -> MonoItemPartitio
         }
     }
 
-    #[cfg(not(llvm_enzyme))]
-    let autodiff_mono_items: Vec<_> = vec![];
-    #[cfg(llvm_enzyme)]
-    let mut autodiff_mono_items: Vec<_> = vec![];
     let mono_items: DefIdSet = items
         .iter()
         .filter_map(|mono_item| match *mono_item {
-            MonoItem::Fn(ref instance) => {
-                #[cfg(llvm_enzyme)]
-                autodiff_mono_items.push((mono_item, instance));
-                Some(instance.def_id())
-            }
+            MonoItem::Fn(ref instance) => Some(instance.def_id()),
             MonoItem::Static(def_id) => Some(def_id),
             _ => None,
         })
         .collect();
 
-    let autodiff_items =
-        autodiff::find_autodiff_source_functions(tcx, &usage_map, autodiff_mono_items);
-    let autodiff_items = tcx.arena.alloc_from_iter(autodiff_items);
-
     // Output monomorphization stats per def_id
     if let SwitchWithOptPath::Enabled(ref path) = tcx.sess.opts.unstable_opts.dump_mono_stats {
         if let Err(err) =
@@ -1235,11 +1211,7 @@ fn collect_and_partition_mono_items(tcx: TyCtxt<'_>, (): ()) -> MonoItemPartitio
         }
     }
 
-    MonoItemPartitions {
-        all_mono_items: tcx.arena.alloc(mono_items),
-        codegen_units,
-        autodiff_items,
-    }
+    MonoItemPartitions { all_mono_items: tcx.arena.alloc(mono_items), codegen_units }
 }
 
 /// Outputs stats about instantiation counts and estimated size, per `MonoItem`'s