Rollup merge of #156245 - bjorn3:move_invocation_temp, r=oli-obk

Move invocation_temp into OutputFilenames

While it was previously defined in Session, it is only ever used with OutputFilenames methods.

Cargo.lock

@@ -4101,6 +4101,7 @@ dependencies = [
 name = "rustc_interface"
 version = "0.0.0"
 dependencies = [
+ "rand 0.9.2",
  "rustc_abi",
  "rustc_ast",
  "rustc_ast_lowering",
@@ -4602,7 +4603,6 @@ version = "0.0.0"
 dependencies = [
  "getopts",
  "libc",
- "rand 0.9.2",
  "rustc_abi",
  "rustc_ast",
  "rustc_data_structures",

compiler/rustc_codegen_cranelift/src/driver/aot.rs

@@ -150,7 +150,6 @@ fn make_module(sess: &Session, name: String) -> UnwindModule<ObjectModule> {
 
 fn emit_cgu(
     output_filenames: &OutputFilenames,
-    invocation_temp: Option<&str>,
     prof: &SelfProfilerRef,
     name: String,
     module: UnwindModule<ObjectModule>,
@@ -166,7 +165,6 @@ fn emit_cgu(
 
     let module_regular = emit_module(
         output_filenames,
-        invocation_temp,
         prof,
         product.object,
         ModuleKind::Regular,
@@ -192,7 +190,6 @@ fn emit_cgu(
 
 fn emit_module(
     output_filenames: &OutputFilenames,
-    invocation_temp: Option<&str>,
     prof: &SelfProfilerRef,
     mut object: cranelift_object::object::write::Object<'_>,
     kind: ModuleKind,
@@ -211,7 +208,7 @@ fn emit_module(
         object.set_section_data(comment_section, producer, 1);
     }
 
-    let tmp_file = output_filenames.temp_path_for_cgu(OutputType::Object, &name, invocation_temp);
+    let tmp_file = output_filenames.temp_path_for_cgu(OutputType::Object, &name);
     let file = match File::create(&tmp_file) {
         Ok(file) => file,
         Err(err) => return Err(format!("error creating object file: {}", err)),
@@ -251,11 +248,8 @@ fn reuse_workproduct_for_cgu(
     cgu: &CodegenUnit<'_>,
 ) -> Result<ModuleCodegenResult, String> {
     let work_product = cgu.previous_work_product(tcx);
-    let obj_out_regular = tcx.output_filenames(()).temp_path_for_cgu(
-        OutputType::Object,
-        cgu.name().as_str(),
-        tcx.sess.invocation_temp.as_deref(),
-    );
+    let obj_out_regular =
+        tcx.output_filenames(()).temp_path_for_cgu(OutputType::Object, cgu.name().as_str());
     let source_file_regular = rustc_incremental::in_incr_comp_dir_sess(
         tcx.sess,
         work_product.saved_files.get("o").expect("no saved object file in work product"),
@@ -394,7 +388,6 @@ fn module_codegen(
     let producer = crate::debuginfo::producer(tcx.sess);
 
     let profiler = tcx.prof.clone();
-    let invocation_temp = tcx.sess.invocation_temp.clone();
     let output_filenames = tcx.output_filenames(()).clone();
     let should_write_ir = crate::pretty_clif::should_write_ir(tcx.sess);
 
@@ -421,19 +414,13 @@ fn module_codegen(
 
         let global_asm_object_file =
             profiler.generic_activity_with_arg("compile assembly", &*cgu_name).run(|| {
-                crate::global_asm::compile_global_asm(
-                    &global_asm_config,
-                    &cgu_name,
-                    global_asm,
-                    invocation_temp.as_deref(),
-                )
+                crate::global_asm::compile_global_asm(&global_asm_config, &cgu_name, global_asm)
             })?;
 
         let codegen_result =
             profiler.generic_activity_with_arg("write object file", &*cgu_name).run(|| {
                 emit_cgu(
                     &global_asm_config.output_filenames,
-                    invocation_temp.as_deref(),
                     &profiler,
                     cgu_name,
                     module,
@@ -456,7 +443,6 @@ fn emit_allocator_module(tcx: TyCtxt<'_>) -> Option<CompiledModule> {
 
         match emit_module(
             tcx.output_filenames(()),
-            tcx.sess.invocation_temp.as_deref(),
             &tcx.sess.prof,
             product.object,
             ModuleKind::Allocator,

compiler/rustc_codegen_cranelift/src/global_asm.rs

@@ -185,7 +185,6 @@ pub(crate) fn compile_global_asm(
     config: &GlobalAsmConfig,
     cgu_name: &str,
     global_asm: String,
-    invocation_temp: Option<&str>,
 ) -> Result<Option<PathBuf>, String> {
     if global_asm.is_empty() {
         return Ok(None);
@@ -200,7 +199,7 @@ pub(crate) fn compile_global_asm(
     global_asm.push('\n');
 
     let global_asm_object_file = add_file_stem_postfix(
-        config.output_filenames.temp_path_for_cgu(OutputType::Object, cgu_name, invocation_temp),
+        config.output_filenames.temp_path_for_cgu(OutputType::Object, cgu_name),
         ".asm",
     );
 

compiler/rustc_codegen_gcc/src/back/write.rs

@@ -29,16 +29,8 @@ pub(crate) fn codegen(
         let lto_mode = module.module_llvm.lto_mode;
         let lto_supported = module.module_llvm.lto_supported;
 
-        let bc_out = cgcx.output_filenames.temp_path_for_cgu(
-            OutputType::Bitcode,
-            &module.name,
-            cgcx.invocation_temp.as_deref(),
-        );
-        let obj_out = cgcx.output_filenames.temp_path_for_cgu(
-            OutputType::Object,
-            &module.name,
-            cgcx.invocation_temp.as_deref(),
-        );
+        let bc_out = cgcx.output_filenames.temp_path_for_cgu(OutputType::Bitcode, &module.name);
+        let obj_out = cgcx.output_filenames.temp_path_for_cgu(OutputType::Object, &module.name);
 
         if config.bitcode_needed() {
             let _timer =
@@ -82,22 +74,15 @@ pub(crate) fn codegen(
         }
 
         if config.emit_ir {
-            let out = cgcx.output_filenames.temp_path_for_cgu(
-                OutputType::LlvmAssembly,
-                &module.name,
-                cgcx.invocation_temp.as_deref(),
-            );
+            let out =
+                cgcx.output_filenames.temp_path_for_cgu(OutputType::LlvmAssembly, &module.name);
             std::fs::write(out, "").expect("write file");
         }
 
         if config.emit_asm {
             let _timer =
                 prof.generic_activity_with_arg("GCC_module_codegen_emit_asm", &*module.name);
-            let path = cgcx.output_filenames.temp_path_for_cgu(
-                OutputType::Assembly,
-                &module.name,
-                cgcx.invocation_temp.as_deref(),
-            );
+            let path = cgcx.output_filenames.temp_path_for_cgu(OutputType::Assembly, &module.name);
             context.compile_to_file(OutputKind::Assembler, path.to_str().expect("path to str"));
         }
 
@@ -215,7 +200,6 @@ pub(crate) fn codegen(
         config.emit_asm,
         config.emit_ir,
         &cgcx.output_filenames,
-        cgcx.invocation_temp.as_deref(),
     )
 }
 

compiler/rustc_codegen_llvm/src/back/write.rs

@@ -117,17 +117,13 @@ pub(crate) fn create_target_machine(tcx: TyCtxt<'_>, mod_name: &str) -> OwnedTar
             tcx.sess.split_debuginfo(),
             tcx.sess.opts.unstable_opts.split_dwarf_kind,
             mod_name,
-            tcx.sess.invocation_temp.as_deref(),
         )
     } else {
         None
     };
 
-    let output_obj_file = Some(tcx.output_filenames(()).temp_path_for_cgu(
-        OutputType::Object,
-        mod_name,
-        tcx.sess.invocation_temp.as_deref(),
-    ));
+    let output_obj_file =
+        Some(tcx.output_filenames(()).temp_path_for_cgu(OutputType::Object, mod_name));
     let config = TargetMachineFactoryConfig { split_dwarf_file, output_obj_file };
 
     target_machine_factory(
@@ -322,11 +318,7 @@ pub(crate) fn save_temp_bitcode(
         return;
     }
     let ext = format!("{name}.bc");
-    let path = cgcx.output_filenames.temp_path_ext_for_cgu(
-        &ext,
-        &module.name,
-        cgcx.invocation_temp.as_deref(),
-    );
+    let path = cgcx.output_filenames.temp_path_ext_for_cgu(&ext, &module.name);
     write_bitcode_to_file(&module.module_llvm, &path)
 }
 
@@ -949,11 +941,8 @@ pub(crate) fn optimize(
         if let Some(thin_lto_buffer) = thin_lto_buffer {
             let thin_lto_buffer = thin_lto_buffer.unwrap();
             module.thin_lto_buffer = Some(thin_lto_buffer.data().to_vec());
-            let bc_summary_out = cgcx.output_filenames.temp_path_for_cgu(
-                OutputType::ThinLinkBitcode,
-                &module.name,
-                cgcx.invocation_temp.as_deref(),
-            );
+            let bc_summary_out =
+                cgcx.output_filenames.temp_path_for_cgu(OutputType::ThinLinkBitcode, &module.name);
             if let Some(thin_lto_summary_buffer) = thin_lto_summary_buffer
                 && let Some(thin_link_bitcode_filename) = bc_summary_out.file_name()
             {
@@ -1008,16 +997,8 @@ pub(crate) fn codegen(
         // copy it to the .o file, and delete the bitcode if it wasn't
         // otherwise requested.
 
-        let bc_out = cgcx.output_filenames.temp_path_for_cgu(
-            OutputType::Bitcode,
-            &module.name,
-            cgcx.invocation_temp.as_deref(),
-        );
-        let obj_out = cgcx.output_filenames.temp_path_for_cgu(
-            OutputType::Object,
-            &module.name,
-            cgcx.invocation_temp.as_deref(),
-        );
+        let bc_out = cgcx.output_filenames.temp_path_for_cgu(OutputType::Bitcode, &module.name);
+        let obj_out = cgcx.output_filenames.temp_path_for_cgu(OutputType::Object, &module.name);
 
         if config.bitcode_needed() {
             if config.emit_bc || config.emit_obj == EmitObj::Bitcode {
@@ -1055,11 +1036,8 @@ pub(crate) fn codegen(
         if config.emit_ir {
             let _timer =
                 prof.generic_activity_with_arg("LLVM_module_codegen_emit_ir", &*module.name);
-            let out = cgcx.output_filenames.temp_path_for_cgu(
-                OutputType::LlvmAssembly,
-                &module.name,
-                cgcx.invocation_temp.as_deref(),
-            );
+            let out =
+                cgcx.output_filenames.temp_path_for_cgu(OutputType::LlvmAssembly, &module.name);
             let out_c = path_to_c_string(&out);
 
             extern "C" fn demangle_callback(
@@ -1103,11 +1081,7 @@ extern "C" fn demangle_callback(
         if config.emit_asm {
             let _timer =
                 prof.generic_activity_with_arg("LLVM_module_codegen_emit_asm", &*module.name);
-            let path = cgcx.output_filenames.temp_path_for_cgu(
-                OutputType::Assembly,
-                &module.name,
-                cgcx.invocation_temp.as_deref(),
-            );
+            let path = cgcx.output_filenames.temp_path_for_cgu(OutputType::Assembly, &module.name);
 
             // We can't use the same module for asm and object code output,
             // because that triggers various errors like invalid IR or broken
@@ -1136,9 +1110,7 @@ extern "C" fn demangle_callback(
                 let _timer =
                     prof.generic_activity_with_arg("LLVM_module_codegen_emit_obj", &*module.name);
 
-                let dwo_out = cgcx
-                    .output_filenames
-                    .temp_path_dwo_for_cgu(&module.name, cgcx.invocation_temp.as_deref());
+                let dwo_out = cgcx.output_filenames.temp_path_dwo_for_cgu(&module.name);
                 let dwo_out = match (cgcx.split_debuginfo, cgcx.split_dwarf_kind) {
                     // Don't change how DWARF is emitted when disabled.
                     (SplitDebuginfo::Off, _) => None,
@@ -1203,7 +1175,6 @@ extern "C" fn demangle_callback(
         config.emit_asm,
         config.emit_ir,
         &cgcx.output_filenames,
-        cgcx.invocation_temp.as_deref(),
     )
 }
 

compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs

@@ -903,7 +903,6 @@ pub(crate) fn build_compile_unit_di_node<'ll, 'tcx>(
             tcx.sess.split_debuginfo(),
             tcx.sess.opts.unstable_opts.split_dwarf_kind,
             codegen_unit_name,
-            tcx.sess.invocation_temp.as_deref(),
         ) {
         // We get a path relative to the working directory from split_dwarf_path
         Some(tcx.sess.source_map().path_mapping().to_real_filename(work_dir, f))

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -112,12 +112,7 @@ pub fn link_binary(
             let path = MaybeTempDir::new(tmpdir, sess.opts.cg.save_temps);
 
             let crate_name = format!("{}", crate_info.local_crate_name);
-            let out_filename = output.file_for_writing(
-                outputs,
-                OutputType::Exe,
-                &crate_name,
-                sess.invocation_temp.as_deref(),
-            );
+            let out_filename = output.file_for_writing(outputs, OutputType::Exe, &crate_name);
             match crate_type {
                 CrateType::Rlib => {
                     let _timer = sess.timer("link_rlib");

compiler/rustc_codegen_ssa/src/back/write.rs

@@ -295,17 +295,13 @@ pub fn new(cgcx: &CodegenContext, module_name: &str) -> TargetMachineFactoryConf
                 cgcx.split_debuginfo,
                 cgcx.split_dwarf_kind,
                 module_name,
-                cgcx.invocation_temp.as_deref(),
             )
         } else {
             None
         };
 
-        let output_obj_file = Some(cgcx.output_filenames.temp_path_for_cgu(
-            OutputType::Object,
-            module_name,
-            cgcx.invocation_temp.as_deref(),
-        ));
+        let output_obj_file =
+            Some(cgcx.output_filenames.temp_path_for_cgu(OutputType::Object, module_name));
         TargetMachineFactoryConfig { split_dwarf_file, output_obj_file }
     }
 }
@@ -332,7 +328,6 @@ pub struct CodegenContext {
     pub time_trace: bool,
     pub crate_types: Vec<CrateType>,
     pub output_filenames: Arc<OutputFilenames>,
-    pub invocation_temp: Option<String>,
     pub module_config: Arc<ModuleConfig>,
     pub opt_level: OptLevel,
     pub backend_features: Vec<String>,
@@ -527,11 +522,7 @@ pub fn produce_final_output_artifacts(
         if let [module] = &compiled_modules.modules[..] {
             // 1) Only one codegen unit. In this case it's no difficulty
             //    to copy `foo.0.x` to `foo.x`.
-            let path = crate_output.temp_path_for_cgu(
-                output_type,
-                &module.name,
-                sess.invocation_temp.as_deref(),
-            );
+            let path = crate_output.temp_path_for_cgu(output_type, &module.name);
             let output = crate_output.path(output_type);
             if !output_type.is_text_output() && output.is_tty() {
                 sess.dcx()
@@ -910,12 +901,7 @@ fn execute_copy_from_cache_work_item(
         module.source.saved_files.get("dwo").as_ref().and_then(|saved_dwarf_object_file| {
             let dwarf_obj_out = cgcx
                 .output_filenames
-                .split_dwarf_path(
-                    cgcx.split_debuginfo,
-                    cgcx.split_dwarf_kind,
-                    &module.name,
-                    cgcx.invocation_temp.as_deref(),
-                )
+                .split_dwarf_path(cgcx.split_debuginfo, cgcx.split_dwarf_kind, &module.name)
                 .expect(
                     "saved dwarf object in work product but `split_dwarf_path` returned `None`",
                 );
@@ -925,11 +911,7 @@ fn execute_copy_from_cache_work_item(
     let mut load_from_incr_cache = |perform, output_type: OutputType| {
         if perform {
             let saved_file = module.source.saved_files.get(output_type.extension())?;
-            let output_path = cgcx.output_filenames.temp_path_for_cgu(
-                output_type,
-                &module.name,
-                cgcx.invocation_temp.as_deref(),
-            );
+            let output_path = cgcx.output_filenames.temp_path_for_cgu(output_type, &module.name);
             load_from_incr_comp_dir(output_path, &saved_file)
         } else {
             None
@@ -1297,7 +1279,6 @@ fn start_executing_work<B: ExtraBackendMethods>(
         split_dwarf_kind: tcx.sess.opts.unstable_opts.split_dwarf_kind,
         parallel: backend.supports_parallel() && !sess.opts.unstable_opts.no_parallel_backend,
         pointer_size: tcx.data_layout.pointer_size(),
-        invocation_temp: sess.invocation_temp.clone(),
     };
 
     // This is the "main loop" of parallel work happening for parallel codegen.

compiler/rustc_codegen_ssa/src/lib.rs

@@ -95,19 +95,14 @@ pub fn into_compiled_module(
         emit_asm: bool,
         emit_ir: bool,
         outputs: &OutputFilenames,
-        invocation_temp: Option<&str>,
     ) -> CompiledModule {
-        let object = emit_obj
-            .then(|| outputs.temp_path_for_cgu(OutputType::Object, &self.name, invocation_temp));
-        let dwarf_object =
-            emit_dwarf_obj.then(|| outputs.temp_path_dwo_for_cgu(&self.name, invocation_temp));
-        let bytecode = emit_bc
-            .then(|| outputs.temp_path_for_cgu(OutputType::Bitcode, &self.name, invocation_temp));
-        let assembly = emit_asm
-            .then(|| outputs.temp_path_for_cgu(OutputType::Assembly, &self.name, invocation_temp));
-        let llvm_ir = emit_ir.then(|| {
-            outputs.temp_path_for_cgu(OutputType::LlvmAssembly, &self.name, invocation_temp)
-        });
+        let object = emit_obj.then(|| outputs.temp_path_for_cgu(OutputType::Object, &self.name));
+        let dwarf_object = emit_dwarf_obj.then(|| outputs.temp_path_dwo_for_cgu(&self.name));
+        let bytecode = emit_bc.then(|| outputs.temp_path_for_cgu(OutputType::Bitcode, &self.name));
+        let assembly =
+            emit_asm.then(|| outputs.temp_path_for_cgu(OutputType::Assembly, &self.name));
+        let llvm_ir =
+            emit_ir.then(|| outputs.temp_path_for_cgu(OutputType::LlvmAssembly, &self.name));
 
         CompiledModule {
             name: self.name,

compiler/rustc_interface/Cargo.toml

@@ -5,6 +5,7 @@ edition = "2024"
 
 [dependencies]
 # tidy-alphabetical-start
+rand = "0.9.0"
 rustc_ast = { path = "../rustc_ast" }
 rustc_ast_lowering = { path = "../rustc_ast_lowering" }
 rustc_ast_passes = { path = "../rustc_ast_passes" }

compiler/rustc_interface/src/util.rs

@@ -5,6 +5,7 @@
 use std::sync::{Arc, OnceLock};
 use std::{env, thread};
 
+use rand::{RngCore, rng};
 use rustc_ast as ast;
 use rustc_attr_parsing::ShouldEmit;
 use rustc_codegen_ssa::back::archive::{ArArchiveBuilderBuilder, ArchiveBuilderBuilder};
@@ -12,6 +13,7 @@
 use rustc_codegen_ssa::target_features::cfg_target_feature;
 use rustc_codegen_ssa::traits::CodegenBackend;
 use rustc_codegen_ssa::{CompiledModules, CrateInfo, TargetConfig};
+use rustc_data_structures::base_n::{CASE_INSENSITIVE, ToBaseN};
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::jobserver::Proxy;
 use rustc_data_structures::sync;
@@ -616,6 +618,12 @@ pub fn build_output_filenames(attrs: &[ast::Attribute], sess: &Session) -> Outpu
             parse_crate_name(sess, attrs, ShouldEmit::Nothing).map(|i| i.0.to_string())
         });
 
+    let invocation_temp = sess
+        .opts
+        .incremental
+        .as_ref()
+        .map(|_| rng().next_u32().to_base_fixed_len(CASE_INSENSITIVE).to_string());
+
     match sess.io.output_file {
         None => {
             // "-" as input file will cause the parser to read from stdin so we
@@ -632,6 +640,7 @@ pub fn build_output_filenames(attrs: &[ast::Attribute], sess: &Session) -> Outpu
                 stem,
                 None,
                 sess.io.temps_dir.clone(),
+                invocation_temp,
                 sess.opts.unstable_opts.split_dwarf_out_dir.clone(),
                 sess.opts.cg.extra_filename.clone(),
                 sess.opts.output_types.clone(),
@@ -662,6 +671,7 @@ pub fn build_output_filenames(attrs: &[ast::Attribute], sess: &Session) -> Outpu
                 out_filestem,
                 ofile,
                 sess.io.temps_dir.clone(),
+                invocation_temp,
                 sess.opts.unstable_opts.split_dwarf_out_dir.clone(),
                 sess.opts.cg.extra_filename.clone(),
                 sess.opts.output_types.clone(),

compiler/rustc_session/Cargo.toml

@@ -6,7 +6,6 @@ edition = "2024"
 [dependencies]
 # tidy-alphabetical-start
 getopts = "0.2"
-rand = "0.9.0"
 rustc_abi = { path = "../rustc_abi" }
 rustc_ast = { path = "../rustc_ast" }
 rustc_data_structures = { path = "../rustc_data_structures" }

compiler/rustc_session/src/config.rs

@@ -1107,13 +1107,10 @@ pub fn file_for_writing(
         outputs: &OutputFilenames,
         flavor: OutputType,
         codegen_unit_name: &str,
-        invocation_temp: Option<&str>,
     ) -> PathBuf {
         match *self {
             OutFileName::Real(ref path) => path.clone(),
-            OutFileName::Stdout => {
-                outputs.temp_path_for_cgu(flavor, codegen_unit_name, invocation_temp)
-            }
+            OutFileName::Stdout => outputs.temp_path_for_cgu(flavor, codegen_unit_name),
         }
     }
 
@@ -1138,6 +1135,17 @@ pub struct OutputFilenames {
     filestem: String,
     pub single_output_file: Option<OutFileName>,
     temps_directory: Option<PathBuf>,
+
+    /// A random string generated per invocation of rustc.
+    ///
+    /// This is prepended to all temporary files so that they do not collide
+    /// during concurrent invocations of rustc, or past invocations that were
+    /// preserved with a flag like `-C save-temps`, since these files may be
+    /// hard linked.
+    // This does not affect incr comp outputs, only where temp files are stored.
+    #[stable_hasher(ignore)]
+    invocation_temp: Option<String>,
+
     explicit_dwo_out_directory: Option<PathBuf>,
     pub outputs: OutputTypes,
 }
@@ -1180,6 +1188,7 @@ pub fn new(
         out_filestem: String,
         single_output_file: Option<OutFileName>,
         temps_directory: Option<PathBuf>,
+        invocation_temp: Option<String>,
         explicit_dwo_out_directory: Option<PathBuf>,
         extra: String,
         outputs: OutputTypes,
@@ -1188,6 +1197,7 @@ pub fn new(
             out_directory,
             single_output_file,
             temps_directory,
+            invocation_temp,
             explicit_dwo_out_directory,
             outputs,
             crate_stem: format!("{out_crate_name}{extra}"),
@@ -1224,23 +1234,14 @@ fn output_path(&self, flavor: OutputType) -> PathBuf {
     /// Gets the path where a compilation artifact of the given type for the
     /// given codegen unit should be placed on disk. If codegen_unit_name is
     /// None, a path distinct from those of any codegen unit will be generated.
-    pub fn temp_path_for_cgu(
-        &self,
-        flavor: OutputType,
-        codegen_unit_name: &str,
-        invocation_temp: Option<&str>,
-    ) -> PathBuf {
+    pub fn temp_path_for_cgu(&self, flavor: OutputType, codegen_unit_name: &str) -> PathBuf {
         let extension = flavor.extension();
-        self.temp_path_ext_for_cgu(extension, codegen_unit_name, invocation_temp)
+        self.temp_path_ext_for_cgu(extension, codegen_unit_name)
     }
 
     /// Like `temp_path`, but specifically for dwarf objects.
-    pub fn temp_path_dwo_for_cgu(
-        &self,
-        codegen_unit_name: &str,
-        invocation_temp: Option<&str>,
-    ) -> PathBuf {
-        let p = self.temp_path_ext_for_cgu(DWARF_OBJECT_EXT, codegen_unit_name, invocation_temp);
+    pub fn temp_path_dwo_for_cgu(&self, codegen_unit_name: &str) -> PathBuf {
+        let p = self.temp_path_ext_for_cgu(DWARF_OBJECT_EXT, codegen_unit_name);
         if let Some(dwo_out) = &self.explicit_dwo_out_directory {
             let mut o = dwo_out.clone();
             o.push(p.file_name().unwrap());
@@ -1252,16 +1253,11 @@ pub fn temp_path_dwo_for_cgu(
 
     /// Like `temp_path`, but also supports things where there is no corresponding
     /// OutputType, like noopt-bitcode or lto-bitcode.
-    pub fn temp_path_ext_for_cgu(
-        &self,
-        ext: &str,
-        codegen_unit_name: &str,
-        invocation_temp: Option<&str>,
-    ) -> PathBuf {
+    pub fn temp_path_ext_for_cgu(&self, ext: &str, codegen_unit_name: &str) -> PathBuf {
         let mut extension = codegen_unit_name.to_string();
 
         // Append `.{invocation_temp}` to ensure temporary files are unique.
-        if let Some(rng) = invocation_temp {
+        if let Some(rng) = &self.invocation_temp {
             extension.push('.');
             extension.push_str(rng);
         }
@@ -1302,10 +1298,9 @@ pub fn split_dwarf_path(
         split_debuginfo_kind: SplitDebuginfo,
         split_dwarf_kind: SplitDwarfKind,
         cgu_name: &str,
-        invocation_temp: Option<&str>,
     ) -> Option<PathBuf> {
-        let obj_out = self.temp_path_for_cgu(OutputType::Object, cgu_name, invocation_temp);
-        let dwo_out = self.temp_path_dwo_for_cgu(cgu_name, invocation_temp);
+        let obj_out = self.temp_path_for_cgu(OutputType::Object, cgu_name);
+        let dwo_out = self.temp_path_dwo_for_cgu(cgu_name);
         match (split_debuginfo_kind, split_dwarf_kind) {
             (SplitDebuginfo::Off, SplitDwarfKind::Single | SplitDwarfKind::Split) => None,
             // Single mode doesn't change how DWARF is emitted, but does add Split DWARF attributes

compiler/rustc_session/src/session.rs

@@ -5,8 +5,6 @@
 use std::sync::atomic::{AtomicBool, AtomicUsize};
 use std::{env, io};
 
-use rand::{RngCore, rng};
-use rustc_data_structures::base_n::{CASE_INSENSITIVE, ToBaseN};
 use rustc_data_structures::flock;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexSet};
 use rustc_data_structures::profiling::{SelfProfiler, SelfProfilerRef};
@@ -163,14 +161,6 @@ pub struct Session {
     target_filesearch: FileSearch,
     host_filesearch: FileSearch,
 
-    /// A random string generated per invocation of rustc.
-    ///
-    /// This is prepended to all temporary files so that they do not collide
-    /// during concurrent invocations of rustc, or past invocations that were
-    /// preserved with a flag like `-C save-temps`, since these files may be
-    /// hard linked.
-    pub invocation_temp: Option<String>,
-
     /// The names of intrinsics that the current codegen backend replaces
     /// with its own implementations.
     pub replaced_intrinsics: FxHashSet<Symbol>,
@@ -1097,11 +1087,6 @@ pub fn build_session(
         filesearch::FileSearch::new(&sopts.search_paths, &target_tlib_path, &target);
     let host_filesearch = filesearch::FileSearch::new(&sopts.search_paths, &host_tlib_path, &host);
 
-    let invocation_temp = sopts
-        .incremental
-        .as_ref()
-        .map(|_| rng().next_u32().to_base_fixed_len(CASE_INSENSITIVE).to_string());
-
     let timings = TimingSectionHandler::new(sopts.json_timings);
 
     let sess = Session {
@@ -1132,7 +1117,6 @@ pub fn build_session(
         file_depinfo: Default::default(),
         target_filesearch,
         host_filesearch,
-        invocation_temp,
         replaced_intrinsics: FxHashSet::default(), // filled by `run_compiler`
         thin_lto_supported: true,                  // filled by `run_compiler`
         mir_opt_bisect_eval_count: AtomicUsize::new(0),