Fix incremental compilation for fat LTO

compiler/rustc_codegen_cranelift/src/driver/aot.rs

@@ -22,8 +22,8 @@ use rustc_errors::{DiagCtxt, DiagCtxtHandle};
 use rustc_middle::dep_graph::WorkProduct;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc_middle::mono::{MonoItem, MonoItemData, Visibility};
-use rustc_session::Session;
 use rustc_session::config::{OptLevel, OutputFilenames, OutputType};
+use rustc_session::{BorrowedIncrCompSession, Session};
 use rustc_span::Symbol;
 
 use crate::base::CodegenedFunction;
@@ -337,6 +337,7 @@ impl WriteBackendMethods for AotDriver {
     fn run_thin_lto(
         _cgcx: &CodegenContext,
         _prof: &SelfProfilerRef,
+        _incr_comp_session: Option<&BorrowedIncrCompSession>,
         _dcx: rustc_errors::DiagCtxtHandle<'_>,
         _exported_symbols_for_lto: &[String],
         _each_linked_rlib_for_lto: &[PathBuf],

compiler/rustc_codegen_gcc/src/back/lto.rs

@@ -148,11 +148,11 @@ fn fat_lto(
     for module in modules {
         match module {
             FatLtoInput::InMemory(m) => in_memory.push(m),
-            FatLtoInput::Serialized { name, bitcode_path } => {
-                info!("pushing serialized module {:?}", name);
+            FatLtoInput::Serialized { wp, bitcode_path } => {
+                info!("pushing serialized module {:?}", wp.cgu_name);
                 serialized_modules.push((
                     SerializedModule::from_file(&bitcode_path),
-                    CString::new(name).unwrap(),
+                    CString::new(wp.cgu_name).unwrap(),
                 ));
             }
         }

compiler/rustc_codegen_gcc/src/lib.rs

@@ -93,7 +93,9 @@ use rustc_errors::{DiagCtxt, DiagCtxtHandle};
 use rustc_middle::dep_graph::{WorkProduct, WorkProductMap};
 use rustc_middle::ty::TyCtxt;
 use rustc_session::config::{OptLevel, OutputFilenames};
-use rustc_session::{CodegenBackendInit, EarlySession, IncrCompSession, Session};
+use rustc_session::{
+    BorrowedIncrCompSession, CodegenBackendInit, EarlySession, IncrCompSession, Session,
+};
 use rustc_span::{Symbol, sym};
 use rustc_target::spec::{RelocModel, TargetTuple};
 use tempfile::TempDir;
@@ -404,6 +406,7 @@ impl WriteBackendMethods for GccCodegenBackend {
     fn run_thin_lto(
         _cgcx: &CodegenContext,
         _prof: &SelfProfilerRef,
+        _incr_comp_session: Option<&BorrowedIncrCompSession>,
         _dcx: DiagCtxtHandle<'_>,
         // FIXME(bjorn3): Limit LTO exports to these symbols
         _exported_symbols_for_lto: &[String],

compiler/rustc_codegen_llvm/src/back/llvm_backend.rs

@@ -20,7 +20,9 @@ use rustc_metadata::EncodedMetadata;
 use rustc_middle::dep_graph::{WorkProduct, WorkProductMap};
 use rustc_middle::ty::TyCtxt;
 use rustc_session::config::{OptLevel, OutputFilenames, PrintKind, PrintRequest};
-use rustc_session::{CodegenBackendInit, EarlySession, IncrCompSession, Session};
+use rustc_session::{
+    BorrowedIncrCompSession, CodegenBackendInit, EarlySession, IncrCompSession, Session,
+};
 use rustc_span::{Symbol, sym};
 use rustc_target::spec::{RelocModel, TlsModel};
 
@@ -120,6 +122,7 @@ impl WriteBackendMethods for LlvmCodegenBackend {
     fn run_thin_lto(
         cgcx: &CodegenContext,
         prof: &SelfProfilerRef,
+        incr_comp_session: Option<&BorrowedIncrCompSession>,
         dcx: DiagCtxtHandle<'_>,
         exported_symbols_for_lto: &[String],
         each_linked_rlib_for_lto: &[PathBuf],
@@ -128,6 +131,7 @@ impl WriteBackendMethods for LlvmCodegenBackend {
         back::lto::run_thin(
             cgcx,
             prof,
+            incr_comp_session,
             dcx,
             exported_symbols_for_lto,
             each_linked_rlib_for_lto,
@@ -377,21 +381,35 @@ impl CodegenBackend for LlvmCodegenBackend {
             });
         }
 
-        (compiled_modules, work_products)
-    }
+        if sess.codegen_units().as_usize() == 1 && sess.opts.unstable_opts.time_llvm_passes {
+            let timings =
+                llvm::build_string(|s| unsafe { llvm::LLVMRustPrintPassTimings(s) }).unwrap();
+            print!("{timings}");
+        }
 
-    fn print_pass_timings(&self) {
-        let timings = llvm::build_string(|s| unsafe { llvm::LLVMRustPrintPassTimings(s) }).unwrap();
-        print!("{timings}");
-    }
+        if sess.print_llvm_stats() {
+            let stats =
+                llvm::build_string(|s| unsafe { llvm::LLVMRustPrintStatistics(s) }).unwrap();
+            print!("{stats}");
+        }
 
-    fn print_statistics(&self) {
-        let stats = llvm::build_string(|s| unsafe { llvm::LLVMRustPrintStatistics(s) }).unwrap();
-        print!("{stats}");
-    }
+        if let Some(out_path) = sess.print_llvm_stats_json() {
+            let llvm_stats_json =
+                llvm::build_string(|s| unsafe { llvm::LLVMRustPrintStatisticsJSON(s) }).unwrap();
+
+            if !llvm_stats_json.is_empty() {
+                if let Err(e) = std::fs::write(&out_path, llvm_stats_json) {
+                    sess.dcx().err(format!("failed to write stats to {out_path}: {e}"));
+                }
+            } else {
+                sess.dcx().warn(format!(
+                    "requested to print LLVM statistics to JSON file {out_path}, but the codegen backend \
+                    did not provide any statistics",
+                ));
+            }
+        }
 
-    fn print_statistics_json(&self) -> String {
-        llvm::build_string(|s| unsafe { llvm::LLVMRustPrintStatisticsJSON(s) }).unwrap()
+        (compiled_modules, work_products)
     }
 
     fn link(

compiler/rustc_codegen_llvm/src/back/lto.rs

@@ -19,7 +19,7 @@ use rustc_data_structures::memmap::Mmap;
 use rustc_data_structures::profiling::SelfProfilerRef;
 use rustc_errors::{DiagCtxt, DiagCtxtHandle};
 use rustc_middle::dep_graph::WorkProduct;
-use rustc_session::config;
+use rustc_session::{BorrowedIncrCompSession, config};
 use rustc_span::bug;
 use rustc_structures::SanitizerSet;
 use tracing::{debug, info};
@@ -184,6 +184,7 @@ pub(crate) fn run_fat(
 pub(crate) fn run_thin(
     cgcx: &CodegenContext,
     prof: &SelfProfilerRef,
+    incr_comp_session: Option<&BorrowedIncrCompSession>,
     dcx: DiagCtxtHandle<'_>,
     exported_symbols_for_lto: &[String],
     each_linked_rlib_for_lto: &[PathBuf],
@@ -199,7 +200,7 @@ pub(crate) fn run_thin(
                       is deferred to the linker"
         );
     }
-    thin_lto(cgcx, prof, dcx, modules, upstream_modules, &symbols_below_threshold)
+    thin_lto(prof, incr_comp_session, dcx, modules, upstream_modules, &symbols_below_threshold)
 }
 
 fn fat_lto(
@@ -225,11 +226,11 @@ fn fat_lto(
     for module in modules {
         match module {
             FatLtoInput::InMemory(m) => in_memory.push(m),
-            FatLtoInput::Serialized { name, bitcode_path } => {
-                info!("pushing serialized module {:?}", name);
+            FatLtoInput::Serialized { wp, bitcode_path } => {
+                info!("pushing serialized module {:?}", wp.cgu_name);
                 serialized_modules.push((
                     SerializedModule::from_file(&bitcode_path),
-                    CString::new(name).unwrap(),
+                    CString::new(wp.cgu_name).unwrap(),
                 ));
             }
         }
@@ -371,8 +372,8 @@ fn fat_lto(
 /// all of the `LtoModuleCodegen` units returned below and destroyed once
 /// they all go out of scope.
 fn thin_lto(
-    cgcx: &CodegenContext,
     prof: &SelfProfilerRef,
+    incr_comp_session: Option<&BorrowedIncrCompSession>,
     dcx: DiagCtxtHandle<'_>,
     modules: Vec<ThinLtoInput<LlvmCodegenBackend>>,
     serialized_modules: Vec<(SerializedModule<ModuleBuffer>, CString)>,
@@ -463,13 +464,12 @@ fn thin_lto(
 
         info!("thin LTO data created");
 
-        let new_key_map_path = cgcx
-            .new_incr_comp_session_dir
-            .as_ref()
-            .map(|dir| dir.join(THIN_LTO_KEYS_INCR_COMP_FILE_NAME));
+        let new_key_map_path = incr_comp_session.as_ref().map(|incr_comp_session| {
+            incr_comp_session.new_session_directory.join(THIN_LTO_KEYS_INCR_COMP_FILE_NAME)
+        });
 
-        let prev_key_map = if let Some(ref old_incr_comp_session_dir) =
-            cgcx.old_incr_comp_session_dir
+        let prev_key_map = if let Some(ref old_incr_comp_session_dir) = incr_comp_session
+            .and_then(|incr_comp_session| incr_comp_session.old_session_directory.as_deref())
         {
             let old_path = old_incr_comp_session_dir.join(THIN_LTO_KEYS_INCR_COMP_FILE_NAME);
 
@@ -481,7 +481,7 @@ fn thin_lto(
             assert!(green_modules.is_empty());
             None
         };
-        let curr_key_map = if cgcx.new_incr_comp_session_dir.is_some() {
+        let curr_key_map = if incr_comp_session.is_some() {
             ThinLTOKeysMap::from_thin_lto_modules(&data, &thin_modules, &module_names)
         } else {
             assert!(green_modules.is_empty());
@@ -506,8 +506,7 @@ fn thin_lto(
             if let (Some(prev_key_map), true) =
                 (prev_key_map.as_ref(), green_modules.contains_key(module_name))
             {
-                assert!(cgcx.old_incr_comp_session_dir.is_some());
-                assert!(cgcx.new_incr_comp_session_dir.is_some());
+                assert!(incr_comp_session.unwrap().old_session_directory.is_some());
 
                 // If a module exists in both the current and the previous session,
                 // and has the same LTO cache key in both sessions, then we can re-use it

compiler/rustc_codegen_ssa/src/assert_module_sources.rs

@@ -111,7 +111,7 @@ impl<'tcx> AssertModuleSource<'tcx> {
 
             if !self.check_config(cfg) {
                 debug!("check_attr: config does not match, ignoring attr");
-                return;
+                continue;
             }
 
             let user_path = module.as_str();