From 12f7ae1ebbfcbe9ab38c92b95b9306312fbef720 Mon Sep 17 00:00:00 2001
From: Ben Kimock <kimockb@gmail.com>
Date: Sun, 28 Jul 2024 16:54:14 -0400
Subject: [PATCH 1/2] Avoid no-op unlink+link dances in incr comp

---
 src/driver/aot.rs | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/driver/aot.rs b/src/driver/aot.rs
index a52b18573b15..d1843f90a07d 100644
--- a/src/driver/aot.rs
+++ b/src/driver/aot.rs
@@ -103,12 +103,14 @@ impl OngoingCodegen {
                             ("o", &module_regular.object.as_ref().unwrap()),
                             ("asm.o", &module_global_asm.object.as_ref().unwrap()),
                         ],
+                        &[],
                     )
                 } else {
                     rustc_incremental::copy_cgu_workproduct_to_incr_comp_cache_dir(
                         sess,
                         &module_regular.name,
                         &[("o", &module_regular.object.as_ref().unwrap())],
+                        &[],
                     )
                 };
                 if let Some((work_product_id, work_product)) = work_product {
@@ -381,6 +383,7 @@ fn emit_cgu(
             bytecode: None,
             assembly: None,
             llvm_ir: None,
+            links_from_incr_cache: Vec::new(),
         }),
         existing_work_product: None,
     })
@@ -437,6 +440,7 @@ fn emit_module(
         bytecode: None,
         assembly: None,
         llvm_ir: None,
+        links_from_incr_cache: Vec::new(),
     })
 }
 
@@ -487,6 +491,7 @@ fn reuse_workproduct_for_cgu(
             bytecode: None,
             assembly: None,
             llvm_ir: None,
+            links_from_incr_cache: Vec::new(),
         },
         module_global_asm: has_global_asm.then(|| CompiledModule {
             name: cgu.name().to_string(),
@@ -496,6 +501,7 @@ fn reuse_workproduct_for_cgu(
             bytecode: None,
             assembly: None,
             llvm_ir: None,
+            links_from_incr_cache: Vec::new(),
         }),
         existing_work_product: Some((cgu.work_product_id(), work_product)),
     })
@@ -637,6 +643,7 @@ fn emit_metadata_module(tcx: TyCtxt<'_>, metadata: &EncodedMetadata) -> Compiled
         bytecode: None,
         assembly: None,
         llvm_ir: None,
+        links_from_incr_cache: Vec::new(),
     }
 }
 
@@ -745,7 +752,6 @@ pub(crate) fn run_aot(
 
     let metadata_module =
         if need_metadata_module { Some(emit_metadata_module(tcx, &metadata)) } else { None };
-
     Box::new(OngoingCodegen {
         modules,
         allocator_module,

From af9f91696bb3f504a6fc7c235e7eb1999d064acb Mon Sep 17 00:00:00 2001
From: Ben Kimock <kimockb@gmail.com>
Date: Tue, 25 Feb 2025 18:41:49 -0500
Subject: [PATCH 2/2] Fill out links_from_incr_cache in cg_clif

---
 src/driver/aot.rs | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/src/driver/aot.rs b/src/driver/aot.rs
index d1843f90a07d..fb7864ae6124 100644
--- a/src/driver/aot.rs
+++ b/src/driver/aot.rs
@@ -464,22 +464,23 @@ fn reuse_workproduct_for_cgu(
             err
         ));
     }
+
     let obj_out_global_asm =
         crate::global_asm::add_file_stem_postfix(obj_out_regular.clone(), ".asm");
-    let has_global_asm = if let Some(asm_o) = work_product.saved_files.get("asm.o") {
+    let source_file_global_asm = if let Some(asm_o) = work_product.saved_files.get("asm.o") {
         let source_file_global_asm = rustc_incremental::in_incr_comp_dir_sess(&tcx.sess, asm_o);
         if let Err(err) = rustc_fs_util::link_or_copy(&source_file_global_asm, &obj_out_global_asm)
         {
             return Err(format!(
                 "unable to copy {} to {}: {}",
-                source_file_regular.display(),
-                obj_out_regular.display(),
+                source_file_global_asm.display(),
+                obj_out_global_asm.display(),
                 err
             ));
         }
-        true
+        Some(source_file_global_asm)
     } else {
-        false
+        None
     };
 
     Ok(ModuleCodegenResult {
@@ -491,9 +492,9 @@ fn reuse_workproduct_for_cgu(
             bytecode: None,
             assembly: None,
             llvm_ir: None,
-            links_from_incr_cache: Vec::new(),
+            links_from_incr_cache: vec![source_file_regular],
         },
-        module_global_asm: has_global_asm.then(|| CompiledModule {
+        module_global_asm: source_file_global_asm.map(|source_file| CompiledModule {
             name: cgu.name().to_string(),
             kind: ModuleKind::Regular,
             object: Some(obj_out_global_asm),
@@ -501,7 +502,7 @@ fn reuse_workproduct_for_cgu(
             bytecode: None,
             assembly: None,
             llvm_ir: None,
-            links_from_incr_cache: Vec::new(),
+            links_from_incr_cache: vec![source_file],
         }),
         existing_work_product: Some((cgu.work_product_id(), work_product)),
     })
@@ -752,6 +753,7 @@ pub(crate) fn run_aot(
 
     let metadata_module =
         if need_metadata_module { Some(emit_metadata_module(tcx, &metadata)) } else { None };
+
     Box::new(OngoingCodegen {
         modules,
         allocator_module,