From 2472d19625fa39ed635a211be397319d2b62cb24 Mon Sep 17 00:00:00 2001 From: bjorn3 <17426603+bjorn3@users.noreply.github.com> Date: Wed, 6 Aug 2025 13:38:26 +0000 Subject: [PATCH 1/3] Include allocator module in LLVM_passes timer --- compiler/rustc_codegen_ssa/src/back/write.rs | 7 +-- compiler/rustc_codegen_ssa/src/base.rs | 56 ++++++++++---------- 2 files changed, 30 insertions(+), 33 deletions(-) diff --git a/compiler/rustc_codegen_ssa/src/back/write.rs b/compiler/rustc_codegen_ssa/src/back/write.rs index aa29afb7f5b11..a2ae03a7611bc 100644 --- a/compiler/rustc_codegen_ssa/src/back/write.rs +++ b/compiler/rustc_codegen_ssa/src/back/write.rs @@ -110,7 +110,6 @@ pub struct ModuleConfig { pub lint_llvm_ir: bool, pub no_prepopulate_passes: bool, pub no_builtins: bool, - pub time_module: bool, pub vectorize_loop: bool, pub vectorize_slp: bool, pub merge_functions: bool, @@ -228,10 +227,6 @@ impl ModuleConfig { no_prepopulate_passes: sess.opts.cg.no_prepopulate_passes, no_builtins: no_builtins || sess.target.no_builtins, - // Exclude metadata and allocator modules from time_passes output, - // since they throw off the "LLVM passes" measurement. - time_module: if_regular!(true, false), - // Copy what clang does by turning on loop vectorization at O2 and // slp vectorization at O3. vectorize_loop: !sess.opts.cg.no_vectorize_loops @@ -1740,7 +1735,7 @@ fn spawn_work<'a, B: ExtraBackendMethods>( llvm_start_time: &mut Option>, work: WorkItem, ) { - if cgcx.config(work.module_kind()).time_module && llvm_start_time.is_none() { + if llvm_start_time.is_none() { *llvm_start_time = Some(cgcx.prof.verbose_generic_activity("LLVM_passes")); } diff --git a/compiler/rustc_codegen_ssa/src/base.rs b/compiler/rustc_codegen_ssa/src/base.rs index b4556ced0b3fb..10a25bb3caaa1 100644 --- a/compiler/rustc_codegen_ssa/src/base.rs +++ b/compiler/rustc_codegen_ssa/src/base.rs @@ -681,33 +681,6 @@ pub fn codegen_crate( let ongoing_codegen = start_async_codegen(backend.clone(), tcx, target_cpu, autodiff_items); - // Codegen an allocator shim, if necessary. - if let Some(kind) = allocator_kind_for_codegen(tcx) { - let llmod_id = - cgu_name_builder.build_cgu_name(LOCAL_CRATE, &["crate"], Some("allocator")).to_string(); - let module_llvm = tcx.sess.time("write_allocator_module", || { - backend.codegen_allocator( - tcx, - &llmod_id, - kind, - // If allocator_kind is Some then alloc_error_handler_kind must - // also be Some. - tcx.alloc_error_handler_kind(()).unwrap(), - ) - }); - - ongoing_codegen.wait_for_signal_to_codegen_item(); - ongoing_codegen.check_for_errors(tcx.sess); - - // These modules are generally cheap and won't throw off scheduling. - let cost = 0; - submit_codegened_module_to_llvm( - &ongoing_codegen.coordinator, - ModuleCodegen::new_allocator(llmod_id, module_llvm), - cost, - ); - } - // For better throughput during parallel processing by LLVM, we used to sort // CGUs largest to smallest. This would lead to better thread utilization // by, for example, preventing a large CGU from being processed last and @@ -823,6 +796,35 @@ pub fn codegen_crate( } } + // Codegen an allocator shim, if necessary. + // Do this last to ensure the LLVM_passes timer doesn't start while no CGUs have been codegened + // yet for the backend to optimize. + if let Some(kind) = allocator_kind_for_codegen(tcx) { + let llmod_id = + cgu_name_builder.build_cgu_name(LOCAL_CRATE, &["crate"], Some("allocator")).to_string(); + let module_llvm = tcx.sess.time("write_allocator_module", || { + backend.codegen_allocator( + tcx, + &llmod_id, + kind, + // If allocator_kind is Some then alloc_error_handler_kind must + // also be Some. + tcx.alloc_error_handler_kind(()).unwrap(), + ) + }); + + ongoing_codegen.wait_for_signal_to_codegen_item(); + ongoing_codegen.check_for_errors(tcx.sess); + + // These modules are generally cheap and won't throw off scheduling. + let cost = 0; + submit_codegened_module_to_llvm( + &ongoing_codegen.coordinator, + ModuleCodegen::new_allocator(llmod_id, module_llvm), + cost, + ); + } + ongoing_codegen.codegen_finished(tcx); // Since the main thread is sometimes blocked during codegen, we keep track From ee38bc06ce68d3f426f191a012ab529eceecb700 Mon Sep 17 00:00:00 2001 From: bjorn3 <17426603+bjorn3@users.noreply.github.com> Date: Wed, 6 Aug 2025 14:03:35 +0000 Subject: [PATCH 2/3] Remove unused field from ModuleConfig --- compiler/rustc_codegen_ssa/src/back/write.rs | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/compiler/rustc_codegen_ssa/src/back/write.rs b/compiler/rustc_codegen_ssa/src/back/write.rs index a2ae03a7611bc..17dcca753987b 100644 --- a/compiler/rustc_codegen_ssa/src/back/write.rs +++ b/compiler/rustc_codegen_ssa/src/back/write.rs @@ -76,12 +76,9 @@ pub struct ModuleConfig { /// Names of additional optimization passes to run. pub passes: Vec, /// Some(level) to optimize at a certain level, or None to run - /// absolutely no optimizations (used for the metadata module). + /// absolutely no optimizations (used for the allocator module). pub opt_level: Option, - /// Some(level) to optimize binary size, or None to not affect program size. - pub opt_size: Option, - pub pgo_gen: SwitchWithOptPath, pub pgo_use: Option, pub pgo_sample_use: Option, @@ -170,7 +167,6 @@ impl ModuleConfig { passes: if_regular!(sess.opts.cg.passes.clone(), vec![]), opt_level: opt_level_and_size, - opt_size: opt_level_and_size, pgo_gen: if_regular!( sess.opts.cg.profile_generate.clone(), From 8f648d7185a8455151951f30357b93dee726c6cb Mon Sep 17 00:00:00 2001 From: bjorn3 <17426603+bjorn3@users.noreply.github.com> Date: Fri, 8 Aug 2025 11:24:28 +0000 Subject: [PATCH 3/3] Remove bitcode_llvm_cmdline It used to be necessary on Apple platforms to ship with the App Store, but XCode 15 has stopped embedding LLVM bitcode and the App Store no longer accepts apps with bitcode embedded. --- compiler/rustc_codegen_llvm/src/back/write.rs | 11 ++++++----- compiler/rustc_codegen_ssa/src/back/write.rs | 2 -- compiler/rustc_target/src/spec/json.rs | 3 --- compiler/rustc_target/src/spec/mod.rs | 3 --- 4 files changed, 6 insertions(+), 13 deletions(-) diff --git a/compiler/rustc_codegen_llvm/src/back/write.rs b/compiler/rustc_codegen_llvm/src/back/write.rs index 85a06f457ebea..62998003ca114 100644 --- a/compiler/rustc_codegen_llvm/src/back/write.rs +++ b/compiler/rustc_codegen_llvm/src/back/write.rs @@ -862,7 +862,7 @@ pub(crate) fn codegen( .generic_activity_with_arg("LLVM_module_codegen_embed_bitcode", &*module.name); let thin_bc = module.thin_lto_buffer.as_deref().expect("cannot find embedded bitcode"); - embed_bitcode(cgcx, llcx, llmod, &config.bc_cmdline, &thin_bc); + embed_bitcode(cgcx, llcx, llmod, &thin_bc); } } @@ -1058,7 +1058,6 @@ fn embed_bitcode( cgcx: &CodegenContext, llcx: &llvm::Context, llmod: &llvm::Module, - cmdline: &str, bitcode: &[u8], ) { // We're adding custom sections to the output object file, but we definitely @@ -1074,7 +1073,9 @@ fn embed_bitcode( // * Mach-O - this is for macOS. Inspecting the source code for the native // linker here shows that the `.llvmbc` and `.llvmcmd` sections are // automatically skipped by the linker. In that case there's nothing extra - // that we need to do here. + // that we need to do here. We do need to make sure that the + // `__LLVM,__cmdline` section exists even though it is empty as otherwise + // ld64 rejects the object file. // // * Wasm - the native LLD linker is hard-coded to skip `.llvmbc` and // `.llvmcmd` sections, so there's nothing extra we need to do. @@ -1111,7 +1112,7 @@ fn embed_bitcode( llvm::set_linkage(llglobal, llvm::Linkage::PrivateLinkage); llvm::LLVMSetGlobalConstant(llglobal, llvm::True); - let llconst = common::bytes_in_context(llcx, cmdline.as_bytes()); + let llconst = common::bytes_in_context(llcx, &[]); let llglobal = llvm::add_global(llmod, common::val_ty(llconst), c"rustc.embedded.cmdline"); llvm::set_initializer(llglobal, llconst); let section = if cgcx.target_is_like_darwin { @@ -1128,7 +1129,7 @@ fn embed_bitcode( let section_flags = if cgcx.is_pe_coff { "n" } else { "e" }; let asm = create_section_with_flags_asm(".llvmbc", section_flags, bitcode); llvm::append_module_inline_asm(llmod, &asm); - let asm = create_section_with_flags_asm(".llvmcmd", section_flags, cmdline.as_bytes()); + let asm = create_section_with_flags_asm(".llvmcmd", section_flags, &[]); llvm::append_module_inline_asm(llmod, &asm); } } diff --git a/compiler/rustc_codegen_ssa/src/back/write.rs b/compiler/rustc_codegen_ssa/src/back/write.rs index 17dcca753987b..7ceb9885716eb 100644 --- a/compiler/rustc_codegen_ssa/src/back/write.rs +++ b/compiler/rustc_codegen_ssa/src/back/write.rs @@ -99,7 +99,6 @@ pub struct ModuleConfig { pub emit_obj: EmitObj, pub emit_thin_lto: bool, pub emit_thin_lto_summary: bool, - pub bc_cmdline: String, // Miscellaneous flags. These are mostly copied from command-line // options. @@ -216,7 +215,6 @@ impl ModuleConfig { sess.opts.output_types.contains_key(&OutputType::ThinLinkBitcode), false ), - bc_cmdline: sess.target.bitcode_llvm_cmdline.to_string(), verify_llvm_ir: sess.verify_llvm_ir(), lint_llvm_ir: sess.opts.unstable_opts.lint_llvm_ir, diff --git a/compiler/rustc_target/src/spec/json.rs b/compiler/rustc_target/src/spec/json.rs index d27c1929aef74..ba7a3a3969e38 100644 --- a/compiler/rustc_target/src/spec/json.rs +++ b/compiler/rustc_target/src/spec/json.rs @@ -167,7 +167,6 @@ impl Target { forward!(main_needs_argc_argv); forward!(has_thread_local); forward!(obj_is_bitcode); - forward!(bitcode_llvm_cmdline); forward_opt!(max_atomic_width); forward_opt!(min_atomic_width); forward!(atomic_cas); @@ -359,7 +358,6 @@ impl ToJson for Target { target_option_val!(main_needs_argc_argv); target_option_val!(has_thread_local); target_option_val!(obj_is_bitcode); - target_option_val!(bitcode_llvm_cmdline); target_option_val!(min_atomic_width); target_option_val!(max_atomic_width); target_option_val!(atomic_cas); @@ -552,7 +550,6 @@ struct TargetSpecJson { main_needs_argc_argv: Option, has_thread_local: Option, obj_is_bitcode: Option, - bitcode_llvm_cmdline: Option>, max_atomic_width: Option, min_atomic_width: Option, atomic_cas: Option, diff --git a/compiler/rustc_target/src/spec/mod.rs b/compiler/rustc_target/src/spec/mod.rs index 033590e01a67d..0c7ff7dd16564 100644 --- a/compiler/rustc_target/src/spec/mod.rs +++ b/compiler/rustc_target/src/spec/mod.rs @@ -2620,8 +2620,6 @@ pub struct TargetOptions { /// If we give emcc .o files that are actually .bc files it /// will 'just work'. pub obj_is_bitcode: bool, - /// Content of the LLVM cmdline section associated with embedded bitcode. - pub bitcode_llvm_cmdline: StaticCow, /// Don't use this field; instead use the `.min_atomic_width()` method. pub min_atomic_width: Option, @@ -2984,7 +2982,6 @@ impl Default for TargetOptions { allow_asm: true, has_thread_local: false, obj_is_bitcode: false, - bitcode_llvm_cmdline: "".into(), min_atomic_width: None, max_atomic_width: None, atomic_cas: true,