src/librustc_codegen_llvm/back/write.rs

   1 use crate::attributes;
   2 use crate::back::bytecode;
   3 use crate::back::lto::ThinBuffer;
   4 use crate::back::profiling::{
   5     selfprofile_after_pass_callback, selfprofile_before_pass_callback, LlvmSelfProfiler,
   6 };
   7 use crate::base;
   8 use crate::common;
   9 use crate::consts;
  10 use crate::context::{get_reloc_model, is_pie_binary};
  11 use crate::llvm::{self, DiagnosticInfo, PassManager, SMDiagnostic};
  12 use crate::llvm_util;
  13 use crate::type_::Type;
  14 use crate::LlvmCodegenBackend;
  15 use crate::ModuleLlvm;
  16 use log::debug;
  17 use rustc::bug;
  18 use rustc::session::config::{self, Lto, OutputType, Passes, Sanitizer, SwitchWithOptPath};
  19 use rustc::session::Session;
  20 use rustc::ty::TyCtxt;
  21 use rustc_codegen_ssa::back::write::{run_assembler, CodegenContext, ModuleConfig};
  22 use rustc_codegen_ssa::traits::*;
  23 use rustc_codegen_ssa::{CompiledModule, ModuleCodegen, RLIB_BYTECODE_EXTENSION};
  24 use rustc_data_structures::small_c_str::SmallCStr;
  25 use rustc_errors::{FatalError, Handler};
  26 use rustc_fs_util::{link_or_copy, path_to_c_string};
  27 use rustc_hir::def_id::LOCAL_CRATE;
  28
  29 use libc::{c_char, c_int, c_uint, c_void, size_t};
  30 use std::ffi::CString;
  31 use std::fs;
  32 use std::io::{self, Write};
  33 use std::path::{Path, PathBuf};
  34 use std::slice;
  35 use std::str;
  36 use std::sync::Arc;
  37
  38 pub const RELOC_MODEL_ARGS: [(&str, llvm::RelocMode); 7] = [
  39     ("pic", llvm::RelocMode::PIC),
  40     ("static", llvm::RelocMode::Static),
  41     ("default", llvm::RelocMode::Default),
  42     ("dynamic-no-pic", llvm::RelocMode::DynamicNoPic),
  43     ("ropi", llvm::RelocMode::ROPI),
  44     ("rwpi", llvm::RelocMode::RWPI),
  45     ("ropi-rwpi", llvm::RelocMode::ROPI_RWPI),
  46 ];
  47
  48 pub const CODE_GEN_MODEL_ARGS: &[(&str, llvm::CodeModel)] = &[
  49     ("small", llvm::CodeModel::Small),
  50     ("kernel", llvm::CodeModel::Kernel),
  51     ("medium", llvm::CodeModel::Medium),
  52     ("large", llvm::CodeModel::Large),
  53 ];
  54
  55 pub const TLS_MODEL_ARGS: [(&str, llvm::ThreadLocalMode); 4] = [
  56     ("global-dynamic", llvm::ThreadLocalMode::GeneralDynamic),
  57     ("local-dynamic", llvm::ThreadLocalMode::LocalDynamic),
  58     ("initial-exec", llvm::ThreadLocalMode::InitialExec),
  59     ("local-exec", llvm::ThreadLocalMode::LocalExec),
  60 ];
  61
  62 pub fn llvm_err(handler: &rustc_errors::Handler, msg: &str) -> FatalError {
  63     match llvm::last_error() {
  64         Some(err) => handler.fatal(&format!("{}: {}", msg, err)),
  65         None => handler.fatal(&msg),
  66     }
  67 }
  68
  69 pub fn write_output_file(
  70     handler: &rustc_errors::Handler,
  71     target: &'ll llvm::TargetMachine,
  72     pm: &llvm::PassManager<'ll>,
  73     m: &'ll llvm::Module,
  74     output: &Path,
  75     file_type: llvm::FileType,
  76 ) -> Result<(), FatalError> {
  77     unsafe {
  78         let output_c = path_to_c_string(output);
  79         let result = llvm::LLVMRustWriteOutputFile(target, pm, m, output_c.as_ptr(), file_type);
  80         result.into_result().map_err(|()| {
  81             let msg = format!("could not write output to {}", output.display());
  82             llvm_err(handler, &msg)
  83         })
  84     }
  85 }
  86
  87 pub fn create_informational_target_machine(
  88     sess: &Session,
  89     find_features: bool,
  90 ) -> &'static mut llvm::TargetMachine {
  91     target_machine_factory(sess, config::OptLevel::No, find_features)()
  92         .unwrap_or_else(|err| llvm_err(sess.diagnostic(), &err).raise())
  93 }
  94
  95 pub fn create_target_machine(
  96     tcx: TyCtxt<'_>,
  97     find_features: bool,
  98 ) -> &'static mut llvm::TargetMachine {
  99     target_machine_factory(&tcx.sess, tcx.backend_optimization_level(LOCAL_CRATE), find_features)()
 100         .unwrap_or_else(|err| llvm_err(tcx.sess.diagnostic(), &err).raise())
 101 }
 102
 103 pub fn to_llvm_opt_settings(
 104     cfg: config::OptLevel,
 105 ) -> (llvm::CodeGenOptLevel, llvm::CodeGenOptSize) {
 106     use self::config::OptLevel::*;
 107     match cfg {
 108         No => (llvm::CodeGenOptLevel::None, llvm::CodeGenOptSizeNone),
 109         Less => (llvm::CodeGenOptLevel::Less, llvm::CodeGenOptSizeNone),
 110         Default => (llvm::CodeGenOptLevel::Default, llvm::CodeGenOptSizeNone),
 111         Aggressive => (llvm::CodeGenOptLevel::Aggressive, llvm::CodeGenOptSizeNone),
 112         Size => (llvm::CodeGenOptLevel::Default, llvm::CodeGenOptSizeDefault),
 113         SizeMin => (llvm::CodeGenOptLevel::Default, llvm::CodeGenOptSizeAggressive),
 114     }
 115 }
 116
 117 fn to_pass_builder_opt_level(cfg: config::OptLevel) -> llvm::PassBuilderOptLevel {
 118     use config::OptLevel::*;
 119     match cfg {
 120         No => llvm::PassBuilderOptLevel::O0,
 121         Less => llvm::PassBuilderOptLevel::O1,
 122         Default => llvm::PassBuilderOptLevel::O2,
 123         Aggressive => llvm::PassBuilderOptLevel::O3,
 124         Size => llvm::PassBuilderOptLevel::Os,
 125         SizeMin => llvm::PassBuilderOptLevel::Oz,
 126     }
 127 }
 128
 129 // If find_features is true this won't access `sess.crate_types` by assuming
 130 // that `is_pie_binary` is false. When we discover LLVM target features
 131 // `sess.crate_types` is uninitialized so we cannot access it.
 132 pub fn target_machine_factory(
 133     sess: &Session,
 134     optlvl: config::OptLevel,
 135     find_features: bool,
 136 ) -> Arc<dyn Fn() -> Result<&'static mut llvm::TargetMachine, String> + Send + Sync> {
 137     let reloc_model = get_reloc_model(sess);
 138
 139     let (opt_level, _) = to_llvm_opt_settings(optlvl);
 140     let use_softfp = sess.opts.cg.soft_float;
 141
 142     let ffunction_sections = sess.target.target.options.function_sections;
 143     let fdata_sections = ffunction_sections;
 144
 145     let code_model_arg =
 146         sess.opts.cg.code_model.as_ref().or(sess.target.target.options.code_model.as_ref());
 147
 148     let code_model = match code_model_arg {
 149         Some(s) => match CODE_GEN_MODEL_ARGS.iter().find(|arg| arg.0 == s) {
 150             Some(x) => x.1,
 151             _ => {
 152                 sess.err(&format!("{:?} is not a valid code model", code_model_arg));
 153                 sess.abort_if_errors();
 154                 bug!();
 155             }
 156         },
 157         None => llvm::CodeModel::None,
 158     };
 159
 160     let features = attributes::llvm_target_features(sess).collect::<Vec<_>>();
 161     let mut singlethread = sess.target.target.options.singlethread;
 162
 163     // On the wasm target once the `atomics` feature is enabled that means that
 164     // we're no longer single-threaded, or otherwise we don't want LLVM to
 165     // lower atomic operations to single-threaded operations.
 166     if singlethread
 167         && sess.target.target.llvm_target.contains("wasm32")
 168         && features.iter().any(|s| *s == "+atomics")
 169     {
 170         singlethread = false;
 171     }
 172
 173     let triple = SmallCStr::new(&sess.target.target.llvm_target);
 174     let cpu = SmallCStr::new(llvm_util::target_cpu(sess));
 175     let features = features.join(",");
 176     let features = CString::new(features).unwrap();
 177     let abi = SmallCStr::new(&sess.target.target.options.llvm_abiname);
 178     let is_pie_binary = !find_features && is_pie_binary(sess);
 179     let trap_unreachable = sess.target.target.options.trap_unreachable;
 180     let emit_stack_size_section = sess.opts.debugging_opts.emit_stack_sizes;
 181
 182     let asm_comments = sess.asm_comments();
 183     let relax_elf_relocations = sess.target.target.options.relax_elf_relocations;
 184     Arc::new(move || {
 185         let tm = unsafe {
 186             llvm::LLVMRustCreateTargetMachine(
 187                 triple.as_ptr(),
 188                 cpu.as_ptr(),
 189                 features.as_ptr(),
 190                 abi.as_ptr(),
 191                 code_model,
 192                 reloc_model,
 193                 opt_level,
 194                 use_softfp,
 195                 is_pie_binary,
 196                 ffunction_sections,
 197                 fdata_sections,
 198                 trap_unreachable,
 199                 singlethread,
 200                 asm_comments,
 201                 emit_stack_size_section,
 202                 relax_elf_relocations,
 203             )
 204         };
 205
 206         tm.ok_or_else(|| {
 207             format!("Could not create LLVM TargetMachine for triple: {}", triple.to_str().unwrap())
 208         })
 209     })
 210 }
 211
 212 pub(crate) fn save_temp_bitcode(
 213     cgcx: &CodegenContext<LlvmCodegenBackend>,
 214     module: &ModuleCodegen<ModuleLlvm>,
 215     name: &str,
 216 ) {
 217     if !cgcx.save_temps {
 218         return;
 219     }
 220     unsafe {
 221         let ext = format!("{}.bc", name);
 222         let cgu = Some(&module.name[..]);
 223         let path = cgcx.output_filenames.temp_path_ext(&ext, cgu);
 224         let cstr = path_to_c_string(&path);
 225         let llmod = module.module_llvm.llmod();
 226         llvm::LLVMWriteBitcodeToFile(llmod, cstr.as_ptr());
 227     }
 228 }
 229
 230 pub struct DiagnosticHandlers<'a> {
 231     data: *mut (&'a CodegenContext<LlvmCodegenBackend>, &'a Handler),
 232     llcx: &'a llvm::Context,
 233 }
 234
 235 impl<'a> DiagnosticHandlers<'a> {
 236     pub fn new(
 237         cgcx: &'a CodegenContext<LlvmCodegenBackend>,
 238         handler: &'a Handler,
 239         llcx: &'a llvm::Context,
 240     ) -> Self {
 241         let data = Box::into_raw(Box::new((cgcx, handler)));
 242         unsafe {
 243             llvm::LLVMRustSetInlineAsmDiagnosticHandler(llcx, inline_asm_handler, data.cast());
 244             llvm::LLVMContextSetDiagnosticHandler(llcx, diagnostic_handler, data.cast());
 245         }
 246         DiagnosticHandlers { data, llcx }
 247     }
 248 }
 249
 250 impl<'a> Drop for DiagnosticHandlers<'a> {
 251     fn drop(&mut self) {
 252         use std::ptr::null_mut;
 253         unsafe {
 254             llvm::LLVMRustSetInlineAsmDiagnosticHandler(self.llcx, inline_asm_handler, null_mut());
 255             llvm::LLVMContextSetDiagnosticHandler(self.llcx, diagnostic_handler, null_mut());
 256             drop(Box::from_raw(self.data));
 257         }
 258     }
 259 }
 260
 261 unsafe extern "C" fn report_inline_asm(
 262     cgcx: &CodegenContext<LlvmCodegenBackend>,
 263     msg: &str,
 264     cookie: c_uint,
 265 ) {
 266     cgcx.diag_emitter.inline_asm_error(cookie as u32, msg.to_owned());
 267 }
 268
 269 unsafe extern "C" fn inline_asm_handler(diag: &SMDiagnostic, user: *const c_void, cookie: c_uint) {
 270     if user.is_null() {
 271         return;
 272     }
 273     let (cgcx, _) = *(user as *const (&CodegenContext<LlvmCodegenBackend>, &Handler));
 274
 275     let msg = llvm::build_string(|s| llvm::LLVMRustWriteSMDiagnosticToString(diag, s))
 276         .expect("non-UTF8 SMDiagnostic");
 277
 278     report_inline_asm(cgcx, &msg, cookie);
 279 }
 280
 281 unsafe extern "C" fn diagnostic_handler(info: &DiagnosticInfo, user: *mut c_void) {
 282     if user.is_null() {
 283         return;
 284     }
 285     let (cgcx, diag_handler) = *(user as *const (&CodegenContext<LlvmCodegenBackend>, &Handler));
 286
 287     match llvm::diagnostic::Diagnostic::unpack(info) {
 288         llvm::diagnostic::InlineAsm(inline) => {
 289             report_inline_asm(cgcx, &llvm::twine_to_string(inline.message), inline.cookie);
 290         }
 291
 292         llvm::diagnostic::Optimization(opt) => {
 293             let enabled = match cgcx.remark {
 294                 Passes::All => true,
 295                 Passes::Some(ref v) => v.iter().any(|s| *s == opt.pass_name),
 296             };
 297
 298             if enabled {
 299                 diag_handler.note_without_error(&format!(
 300                     "optimization {} for {} at {}:{}:{}: {}",
 301                     opt.kind.describe(),
 302                     opt.pass_name,
 303                     opt.filename,
 304                     opt.line,
 305                     opt.column,
 306                     opt.message
 307                 ));
 308             }
 309         }
 310         llvm::diagnostic::PGO(diagnostic_ref) | llvm::diagnostic::Linker(diagnostic_ref) => {
 311             let msg = llvm::build_string(|s| {
 312                 llvm::LLVMRustWriteDiagnosticInfoToString(diagnostic_ref, s)
 313             })
 314             .expect("non-UTF8 diagnostic");
 315             diag_handler.warn(&msg);
 316         }
 317         llvm::diagnostic::UnknownDiagnostic(..) => {}
 318     }
 319 }
 320
 321 fn get_pgo_gen_path(config: &ModuleConfig) -> Option<CString> {
 322     match config.pgo_gen {
 323         SwitchWithOptPath::Enabled(ref opt_dir_path) => {
 324             let path = if let Some(dir_path) = opt_dir_path {
 325                 dir_path.join("default_%m.profraw")
 326             } else {
 327                 PathBuf::from("default_%m.profraw")
 328             };
 329
 330             Some(CString::new(format!("{}", path.display())).unwrap())
 331         }
 332         SwitchWithOptPath::Disabled => None,
 333     }
 334 }
 335
 336 fn get_pgo_use_path(config: &ModuleConfig) -> Option<CString> {
 337     config
 338         .pgo_use
 339         .as_ref()
 340         .map(|path_buf| CString::new(path_buf.to_string_lossy().as_bytes()).unwrap())
 341 }
 342
 343 pub(crate) fn should_use_new_llvm_pass_manager(config: &ModuleConfig) -> bool {
 344     // We only support the new pass manager starting with LLVM 9.
 345     if llvm_util::get_major_version() < 9 {
 346         return false;
 347     }
 348
 349     // The new pass manager is disabled by default.
 350     config.new_llvm_pass_manager.unwrap_or(false)
 351 }
 352
 353 pub(crate) unsafe fn optimize_with_new_llvm_pass_manager(
 354     cgcx: &CodegenContext<LlvmCodegenBackend>,
 355     module: &ModuleCodegen<ModuleLlvm>,
 356     config: &ModuleConfig,
 357     opt_level: config::OptLevel,
 358     opt_stage: llvm::OptStage,
 359 ) {
 360     let unroll_loops =
 361         opt_level != config::OptLevel::Size && opt_level != config::OptLevel::SizeMin;
 362     let using_thin_buffers = opt_stage == llvm::OptStage::PreLinkThinLTO || config.bitcode_needed();
 363     let pgo_gen_path = get_pgo_gen_path(config);
 364     let pgo_use_path = get_pgo_use_path(config);
 365     let is_lto = opt_stage == llvm::OptStage::ThinLTO || opt_stage == llvm::OptStage::FatLTO;
 366     // Sanitizer instrumentation is only inserted during the pre-link optimization stage.
 367     let sanitizer_options = if !is_lto {
 368         config.sanitizer.as_ref().map(|s| llvm::SanitizerOptions {
 369             sanitize_memory: *s == Sanitizer::Memory,
 370             sanitize_thread: *s == Sanitizer::Thread,
 371             sanitize_address: *s == Sanitizer::Address,
 372             sanitize_recover: config.sanitizer_recover.contains(s),
 373             sanitize_memory_track_origins: config.sanitizer_memory_track_origins as c_int,
 374         })
 375     } else {
 376         None
 377     };
 378
 379     let llvm_selfprofiler = if cgcx.prof.llvm_recording_enabled() {
 380         let mut llvm_profiler = LlvmSelfProfiler::new(cgcx.prof.get_self_profiler().unwrap());
 381         &mut llvm_profiler as *mut _ as *mut c_void
 382     } else {
 383         std::ptr::null_mut()
 384     };
 385
 386     // FIXME: NewPM doesn't provide a facility to pass custom InlineParams.
 387     // We would have to add upstream support for this first, before we can support
 388     // config.inline_threshold and our more aggressive default thresholds.
 389     // FIXME: NewPM uses an different and more explicit way to textually represent
 390     // pass pipelines. It would probably make sense to expose this, but it would
 391     // require a different format than the current -C passes.
 392     llvm::LLVMRustOptimizeWithNewPassManager(
 393         module.module_llvm.llmod(),
 394         &*module.module_llvm.tm,
 395         to_pass_builder_opt_level(opt_level),
 396         opt_stage,
 397         config.no_prepopulate_passes,
 398         config.verify_llvm_ir,
 399         using_thin_buffers,
 400         config.merge_functions,
 401         unroll_loops,
 402         config.vectorize_slp,
 403         config.vectorize_loop,
 404         config.no_builtins,
 405         sanitizer_options.as_ref(),
 406         pgo_gen_path.as_ref().map_or(std::ptr::null(), |s| s.as_ptr()),
 407         pgo_use_path.as_ref().map_or(std::ptr::null(), |s| s.as_ptr()),
 408         llvm_selfprofiler,
 409         selfprofile_before_pass_callback,
 410         selfprofile_after_pass_callback,
 411     );
 412 }
 413
 414 // Unsafe due to LLVM calls.
 415 pub(crate) unsafe fn optimize(
 416     cgcx: &CodegenContext<LlvmCodegenBackend>,
 417     diag_handler: &Handler,
 418     module: &ModuleCodegen<ModuleLlvm>,
 419     config: &ModuleConfig,
 420 ) -> Result<(), FatalError> {
 421     let _timer = cgcx.prof.generic_activity_with_arg("LLVM_module_optimize", &module.name[..]);
 422
 423     let llmod = module.module_llvm.llmod();
 424     let llcx = &*module.module_llvm.llcx;
 425     let tm = &*module.module_llvm.tm;
 426     let _handlers = DiagnosticHandlers::new(cgcx, diag_handler, llcx);
 427
 428     let module_name = module.name.clone();
 429     let module_name = Some(&module_name[..]);
 430
 431     if config.emit_no_opt_bc {
 432         let out = cgcx.output_filenames.temp_path_ext("no-opt.bc", module_name);
 433         let out = path_to_c_string(&out);
 434         llvm::LLVMWriteBitcodeToFile(llmod, out.as_ptr());
 435     }
 436
 437     if let Some(opt_level) = config.opt_level {
 438         if should_use_new_llvm_pass_manager(config) {
 439             let opt_stage = match cgcx.lto {
 440                 Lto::Fat => llvm::OptStage::PreLinkFatLTO,
 441                 Lto::Thin | Lto::ThinLocal => llvm::OptStage::PreLinkThinLTO,
 442                 _ if cgcx.opts.cg.linker_plugin_lto.enabled() => llvm::OptStage::PreLinkThinLTO,
 443                 _ => llvm::OptStage::PreLinkNoLTO,
 444             };
 445             optimize_with_new_llvm_pass_manager(cgcx, module, config, opt_level, opt_stage);
 446             return Ok(());
 447         }
 448
 449         if cgcx.prof.llvm_recording_enabled() {
 450             diag_handler
 451                 .warn("`-Z self-profile-events = llvm` requires `-Z new-llvm-pass-manager`");
 452         }
 453
 454         // Create the two optimizing pass managers. These mirror what clang
 455         // does, and are by populated by LLVM's default PassManagerBuilder.
 456         // Each manager has a different set of passes, but they also share
 457         // some common passes.
 458         let fpm = llvm::LLVMCreateFunctionPassManagerForModule(llmod);
 459         let mpm = llvm::LLVMCreatePassManager();
 460
 461         {
 462             let find_pass = |pass_name: &str| {
 463                 let pass_name = SmallCStr::new(pass_name);
 464                 llvm::LLVMRustFindAndCreatePass(pass_name.as_ptr())
 465             };
 466
 467             if config.verify_llvm_ir {
 468                 // Verification should run as the very first pass.
 469                 llvm::LLVMRustAddPass(fpm, find_pass("verify").unwrap());
 470             }
 471
 472             let mut extra_passes = Vec::new();
 473             let mut have_name_anon_globals_pass = false;
 474
 475             for pass_name in &config.passes {
 476                 if pass_name == "lint" {
 477                     // Linting should also be performed early, directly on the generated IR.
 478                     llvm::LLVMRustAddPass(fpm, find_pass("lint").unwrap());
 479                     continue;
 480                 }
 481
 482                 if let Some(pass) = find_pass(pass_name) {
 483                     extra_passes.push(pass);
 484                 } else {
 485                     diag_handler.warn(&format!("unknown pass `{}`, ignoring", pass_name));
 486                 }
 487
 488                 if pass_name == "name-anon-globals" {
 489                     have_name_anon_globals_pass = true;
 490                 }
 491             }
 492
 493             add_sanitizer_passes(config, &mut extra_passes);
 494
 495             // Some options cause LLVM bitcode to be emitted, which uses ThinLTOBuffers, so we need
 496             // to make sure we run LLVM's NameAnonGlobals pass when emitting bitcode; otherwise
 497             // we'll get errors in LLVM.
 498             let using_thin_buffers = config.bitcode_needed();
 499             if !config.no_prepopulate_passes {
 500                 llvm::LLVMAddAnalysisPasses(tm, fpm);
 501                 llvm::LLVMAddAnalysisPasses(tm, mpm);
 502                 let opt_level = to_llvm_opt_settings(opt_level).0;
 503                 let prepare_for_thin_lto = cgcx.lto == Lto::Thin
 504                     || cgcx.lto == Lto::ThinLocal
 505                     || (cgcx.lto != Lto::Fat && cgcx.opts.cg.linker_plugin_lto.enabled());
 506                 with_llvm_pmb(llmod, &config, opt_level, prepare_for_thin_lto, &mut |b| {
 507                     llvm::LLVMRustAddLastExtensionPasses(
 508                         b,
 509                         extra_passes.as_ptr(),
 510                         extra_passes.len() as size_t,
 511                     );
 512                     llvm::LLVMPassManagerBuilderPopulateFunctionPassManager(b, fpm);
 513                     llvm::LLVMPassManagerBuilderPopulateModulePassManager(b, mpm);
 514                 });
 515
 516                 have_name_anon_globals_pass = have_name_anon_globals_pass || prepare_for_thin_lto;
 517                 if using_thin_buffers && !prepare_for_thin_lto {
 518                     llvm::LLVMRustAddPass(mpm, find_pass("name-anon-globals").unwrap());
 519                     have_name_anon_globals_pass = true;
 520                 }
 521             } else {
 522                 // If we don't use the standard pipeline, directly populate the MPM
 523                 // with the extra passes.
 524                 for pass in extra_passes {
 525                     llvm::LLVMRustAddPass(mpm, pass);
 526                 }
 527             }
 528
 529             if using_thin_buffers && !have_name_anon_globals_pass {
 530                 // As described above, this will probably cause an error in LLVM
 531                 if config.no_prepopulate_passes {
 532                     diag_handler.err(
 533                         "The current compilation is going to use thin LTO buffers \
 534                                       without running LLVM's NameAnonGlobals pass. \
 535                                       This will likely cause errors in LLVM. Consider adding \
 536                                       -C passes=name-anon-globals to the compiler command line.",
 537                     );
 538                 } else {
 539                     bug!(
 540                         "We are using thin LTO buffers without running the NameAnonGlobals pass. \
 541                           This will likely cause errors in LLVM and should never happen."
 542                     );
 543                 }
 544             }
 545         }
 546
 547         diag_handler.abort_if_errors();
 548
 549         // Finally, run the actual optimization passes
 550         {
 551             let _timer = cgcx.prof.extra_verbose_generic_activity(
 552                 "LLVM_module_optimize_function_passes",
 553                 &module.name[..],
 554             );
 555             llvm::LLVMRustRunFunctionPassManager(fpm, llmod);
 556         }
 557         {
 558             let _timer = cgcx.prof.extra_verbose_generic_activity(
 559                 "LLVM_module_optimize_module_passes",
 560                 &module.name[..],
 561             );
 562             llvm::LLVMRunPassManager(mpm, llmod);
 563         }
 564
 565         // Deallocate managers that we're now done with
 566         llvm::LLVMDisposePassManager(fpm);
 567         llvm::LLVMDisposePassManager(mpm);
 568     }
 569     Ok(())
 570 }
 571
 572 unsafe fn add_sanitizer_passes(config: &ModuleConfig, passes: &mut Vec<&'static mut llvm::Pass>) {
 573     let sanitizer = match &config.sanitizer {
 574         None => return,
 575         Some(s) => s,
 576     };
 577
 578     let recover = config.sanitizer_recover.contains(sanitizer);
 579     match sanitizer {
 580         Sanitizer::Address => {
 581             passes.push(llvm::LLVMRustCreateAddressSanitizerFunctionPass(recover));
 582             passes.push(llvm::LLVMRustCreateModuleAddressSanitizerPass(recover));
 583         }
 584         Sanitizer::Memory => {
 585             let track_origins = config.sanitizer_memory_track_origins as c_int;
 586             passes.push(llvm::LLVMRustCreateMemorySanitizerPass(track_origins, recover));
 587         }
 588         Sanitizer::Thread => {
 589             passes.push(llvm::LLVMRustCreateThreadSanitizerPass());
 590         }
 591         Sanitizer::Leak => {}
 592     }
 593 }
 594
 595 pub(crate) unsafe fn codegen(
 596     cgcx: &CodegenContext<LlvmCodegenBackend>,
 597     diag_handler: &Handler,
 598     module: ModuleCodegen<ModuleLlvm>,
 599     config: &ModuleConfig,
 600 ) -> Result<CompiledModule, FatalError> {
 601     let _timer = cgcx.prof.generic_activity_with_arg("LLVM_module_codegen", &module.name[..]);
 602     {
 603         let llmod = module.module_llvm.llmod();
 604         let llcx = &*module.module_llvm.llcx;
 605         let tm = &*module.module_llvm.tm;
 606         let module_name = module.name.clone();
 607         let module_name = Some(&module_name[..]);
 608         let handlers = DiagnosticHandlers::new(cgcx, diag_handler, llcx);
 609
 610         if cgcx.msvc_imps_needed {
 611             create_msvc_imps(cgcx, llcx, llmod);
 612         }
 613
 614         // A codegen-specific pass manager is used to generate object
 615         // files for an LLVM module.
 616         //
 617         // Apparently each of these pass managers is a one-shot kind of
 618         // thing, so we create a new one for each type of output. The
 619         // pass manager passed to the closure should be ensured to not
 620         // escape the closure itself, and the manager should only be
 621         // used once.
 622         unsafe fn with_codegen<'ll, F, R>(
 623             tm: &'ll llvm::TargetMachine,
 624             llmod: &'ll llvm::Module,
 625             no_builtins: bool,
 626             f: F,
 627         ) -> R
 628         where
 629             F: FnOnce(&'ll mut PassManager<'ll>) -> R,
 630         {
 631             let cpm = llvm::LLVMCreatePassManager();
 632             llvm::LLVMAddAnalysisPasses(tm, cpm);
 633             llvm::LLVMRustAddLibraryInfo(cpm, llmod, no_builtins);
 634             f(cpm)
 635         }
 636
 637         // If we don't have the integrated assembler, then we need to emit asm
 638         // from LLVM and use `gcc` to create the object file.
 639         let asm_to_obj = config.emit_obj && config.no_integrated_as;
 640
 641         // Change what we write and cleanup based on whether obj files are
 642         // just llvm bitcode. In that case write bitcode, and possibly
 643         // delete the bitcode if it wasn't requested. Don't generate the
 644         // machine code, instead copy the .o file from the .bc
 645         let write_bc = config.emit_bc || config.obj_is_bitcode;
 646         let rm_bc = !config.emit_bc && config.obj_is_bitcode;
 647         let write_obj = config.emit_obj && !config.obj_is_bitcode && !asm_to_obj;
 648         let copy_bc_to_obj = config.emit_obj && config.obj_is_bitcode;
 649
 650         let bc_out = cgcx.output_filenames.temp_path(OutputType::Bitcode, module_name);
 651         let obj_out = cgcx.output_filenames.temp_path(OutputType::Object, module_name);
 652
 653         if write_bc || config.emit_bc_compressed || config.embed_bitcode {
 654             let _timer = cgcx
 655                 .prof
 656                 .generic_activity_with_arg("LLVM_module_codegen_make_bitcode", &module.name[..]);
 657             let thin = ThinBuffer::new(llmod);
 658             let data = thin.data();
 659
 660             if write_bc {
 661                 let _timer = cgcx.prof.generic_activity_with_arg(
 662                     "LLVM_module_codegen_emit_bitcode",
 663                     &module.name[..],
 664                 );
 665                 if let Err(e) = fs::write(&bc_out, data) {
 666                     let msg = format!("failed to write bytecode to {}: {}", bc_out.display(), e);
 667                     diag_handler.err(&msg);
 668                 }
 669             }
 670
 671             if config.embed_bitcode {
 672                 let _timer = cgcx.prof.generic_activity_with_arg(
 673                     "LLVM_module_codegen_embed_bitcode",
 674                     &module.name[..],
 675                 );
 676                 embed_bitcode(cgcx, llcx, llmod, Some(data));
 677             }
 678
 679             if config.emit_bc_compressed {
 680                 let _timer = cgcx.prof.generic_activity_with_arg(
 681                     "LLVM_module_codegen_emit_compressed_bitcode",
 682                     &module.name[..],
 683                 );
 684                 let dst = bc_out.with_extension(RLIB_BYTECODE_EXTENSION);
 685                 let data = bytecode::encode(&module.name, data);
 686                 if let Err(e) = fs::write(&dst, data) {
 687                     let msg = format!("failed to write bytecode to {}: {}", dst.display(), e);
 688                     diag_handler.err(&msg);
 689                 }
 690             }
 691         } else if config.embed_bitcode_marker {
 692             embed_bitcode(cgcx, llcx, llmod, None);
 693         }
 694
 695         {
 696             if config.emit_ir {
 697                 let _timer = cgcx
 698                     .prof
 699                     .generic_activity_with_arg("LLVM_module_codegen_emit_ir", &module.name[..]);
 700                 let out = cgcx.output_filenames.temp_path(OutputType::LlvmAssembly, module_name);
 701                 let out_c = path_to_c_string(&out);
 702
 703                 extern "C" fn demangle_callback(
 704                     input_ptr: *const c_char,
 705                     input_len: size_t,
 706                     output_ptr: *mut c_char,
 707                     output_len: size_t,
 708                 ) -> size_t {
 709                     let input = unsafe {
 710                         slice::from_raw_parts(input_ptr as *const u8, input_len as usize)
 711                     };
 712
 713                     let input = match str::from_utf8(input) {
 714                         Ok(s) => s,
 715                         Err(_) => return 0,
 716                     };
 717
 718                     let output = unsafe {
 719                         slice::from_raw_parts_mut(output_ptr as *mut u8, output_len as usize)
 720                     };
 721                     let mut cursor = io::Cursor::new(output);
 722
 723                     let demangled = match rustc_demangle::try_demangle(input) {
 724                         Ok(d) => d,
 725                         Err(_) => return 0,
 726                     };
 727
 728                     if let Err(_) = write!(cursor, "{:#}", demangled) {
 729                         // Possible only if provided buffer is not big enough
 730                         return 0;
 731                     }
 732
 733                     cursor.position() as size_t
 734                 }
 735
 736                 let result = llvm::LLVMRustPrintModule(llmod, out_c.as_ptr(), demangle_callback);
 737                 result.into_result().map_err(|()| {
 738                     let msg = format!("failed to write LLVM IR to {}", out.display());
 739                     llvm_err(diag_handler, &msg)
 740                 })?;
 741             }
 742
 743             if config.emit_asm || asm_to_obj {
 744                 let _timer = cgcx
 745                     .prof
 746                     .generic_activity_with_arg("LLVM_module_codegen_emit_asm", &module.name[..]);
 747                 let path = cgcx.output_filenames.temp_path(OutputType::Assembly, module_name);
 748
 749                 // We can't use the same module for asm and binary output, because that triggers
 750                 // various errors like invalid IR or broken binaries, so we might have to clone the
 751                 // module to produce the asm output
 752                 let llmod = if config.emit_obj { llvm::LLVMCloneModule(llmod) } else { llmod };
 753                 with_codegen(tm, llmod, config.no_builtins, |cpm| {
 754                     write_output_file(
 755                         diag_handler,
 756                         tm,
 757                         cpm,
 758                         llmod,
 759                         &path,
 760                         llvm::FileType::AssemblyFile,
 761                     )
 762                 })?;
 763             }
 764
 765             if write_obj {
 766                 let _timer = cgcx
 767                     .prof
 768                     .generic_activity_with_arg("LLVM_module_codegen_emit_obj", &module.name[..]);
 769                 with_codegen(tm, llmod, config.no_builtins, |cpm| {
 770                     write_output_file(
 771                         diag_handler,
 772                         tm,
 773                         cpm,
 774                         llmod,
 775                         &obj_out,
 776                         llvm::FileType::ObjectFile,
 777                     )
 778                 })?;
 779             } else if asm_to_obj {
 780                 let _timer = cgcx
 781                     .prof
 782                     .generic_activity_with_arg("LLVM_module_codegen_asm_to_obj", &module.name[..]);
 783                 let assembly = cgcx.output_filenames.temp_path(OutputType::Assembly, module_name);
 784                 run_assembler(cgcx, diag_handler, &assembly, &obj_out);
 785
 786                 if !config.emit_asm && !cgcx.save_temps {
 787                     drop(fs::remove_file(&assembly));
 788                 }
 789             }
 790         }
 791
 792         if copy_bc_to_obj {
 793             debug!("copying bitcode {:?} to obj {:?}", bc_out, obj_out);
 794             if let Err(e) = link_or_copy(&bc_out, &obj_out) {
 795                 diag_handler.err(&format!("failed to copy bitcode to object file: {}", e));
 796             }
 797         }
 798
 799         if rm_bc {
 800             debug!("removing_bitcode {:?}", bc_out);
 801             if let Err(e) = fs::remove_file(&bc_out) {
 802                 diag_handler.err(&format!("failed to remove bitcode: {}", e));
 803             }
 804         }
 805
 806         drop(handlers);
 807     }
 808     Ok(module.into_compiled_module(
 809         config.emit_obj,
 810         config.emit_bc,
 811         config.emit_bc_compressed,
 812         &cgcx.output_filenames,
 813     ))
 814 }
 815
 816 /// Embed the bitcode of an LLVM module in the LLVM module itself.
 817 ///
 818 /// This is done primarily for iOS where it appears to be standard to compile C
 819 /// code at least with `-fembed-bitcode` which creates two sections in the
 820 /// executable:
 821 ///
 822 /// * __LLVM,__bitcode
 823 /// * __LLVM,__cmdline
 824 ///
 825 /// It appears *both* of these sections are necessary to get the linker to
 826 /// recognize what's going on. For us though we just always throw in an empty
 827 /// cmdline section.
 828 ///
 829 /// Furthermore debug/O1 builds don't actually embed bitcode but rather just
 830 /// embed an empty section.
 831 ///
 832 /// Basically all of this is us attempting to follow in the footsteps of clang
 833 /// on iOS. See #35968 for lots more info.
 834 unsafe fn embed_bitcode(
 835     cgcx: &CodegenContext<LlvmCodegenBackend>,
 836     llcx: &llvm::Context,
 837     llmod: &llvm::Module,
 838     bitcode: Option<&[u8]>,
 839 ) {
 840     let llconst = common::bytes_in_context(llcx, bitcode.unwrap_or(&[]));
 841     let llglobal = llvm::LLVMAddGlobal(
 842         llmod,
 843         common::val_ty(llconst),
 844         "rustc.embedded.module\0".as_ptr().cast(),
 845     );
 846     llvm::LLVMSetInitializer(llglobal, llconst);
 847
 848     let is_apple = cgcx.opts.target_triple.triple().contains("-ios")
 849         || cgcx.opts.target_triple.triple().contains("-darwin");
 850
 851     let section = if is_apple { "__LLVM,__bitcode\0" } else { ".llvmbc\0" };
 852     llvm::LLVMSetSection(llglobal, section.as_ptr().cast());
 853     llvm::LLVMRustSetLinkage(llglobal, llvm::Linkage::PrivateLinkage);
 854     llvm::LLVMSetGlobalConstant(llglobal, llvm::True);
 855
 856     let llconst = common::bytes_in_context(llcx, &[]);
 857     let llglobal = llvm::LLVMAddGlobal(
 858         llmod,
 859         common::val_ty(llconst),
 860         "rustc.embedded.cmdline\0".as_ptr().cast(),
 861     );
 862     llvm::LLVMSetInitializer(llglobal, llconst);
 863     let section = if is_apple { "__LLVM,__cmdline\0" } else { ".llvmcmd\0" };
 864     llvm::LLVMSetSection(llglobal, section.as_ptr().cast());
 865     llvm::LLVMRustSetLinkage(llglobal, llvm::Linkage::PrivateLinkage);
 866 }
 867
 868 pub unsafe fn with_llvm_pmb(
 869     llmod: &llvm::Module,
 870     config: &ModuleConfig,
 871     opt_level: llvm::CodeGenOptLevel,
 872     prepare_for_thin_lto: bool,
 873     f: &mut dyn FnMut(&llvm::PassManagerBuilder),
 874 ) {
 875     use std::ptr;
 876
 877     // Create the PassManagerBuilder for LLVM. We configure it with
 878     // reasonable defaults and prepare it to actually populate the pass
 879     // manager.
 880     let builder = llvm::LLVMPassManagerBuilderCreate();
 881     let opt_size =
 882         config.opt_size.map(|x| to_llvm_opt_settings(x).1).unwrap_or(llvm::CodeGenOptSizeNone);
 883     let inline_threshold = config.inline_threshold;
 884     let pgo_gen_path = get_pgo_gen_path(config);
 885     let pgo_use_path = get_pgo_use_path(config);
 886
 887     llvm::LLVMRustConfigurePassManagerBuilder(
 888         builder,
 889         opt_level,
 890         config.merge_functions,
 891         config.vectorize_slp,
 892         config.vectorize_loop,
 893         prepare_for_thin_lto,
 894         pgo_gen_path.as_ref().map_or(ptr::null(), |s| s.as_ptr()),
 895         pgo_use_path.as_ref().map_or(ptr::null(), |s| s.as_ptr()),
 896     );
 897
 898     llvm::LLVMPassManagerBuilderSetSizeLevel(builder, opt_size as u32);
 899
 900     if opt_size != llvm::CodeGenOptSizeNone {
 901         llvm::LLVMPassManagerBuilderSetDisableUnrollLoops(builder, 1);
 902     }
 903
 904     llvm::LLVMRustAddBuilderLibraryInfo(builder, llmod, config.no_builtins);
 905
 906     // Here we match what clang does (kinda). For O0 we only inline
 907     // always-inline functions (but don't add lifetime intrinsics), at O1 we
 908     // inline with lifetime intrinsics, and O2+ we add an inliner with a
 909     // thresholds copied from clang.
 910     match (opt_level, opt_size, inline_threshold) {
 911         (.., Some(t)) => {
 912             llvm::LLVMPassManagerBuilderUseInlinerWithThreshold(builder, t as u32);
 913         }
 914         (llvm::CodeGenOptLevel::Aggressive, ..) => {
 915             llvm::LLVMPassManagerBuilderUseInlinerWithThreshold(builder, 275);
 916         }
 917         (_, llvm::CodeGenOptSizeDefault, _) => {
 918             llvm::LLVMPassManagerBuilderUseInlinerWithThreshold(builder, 75);
 919         }
 920         (_, llvm::CodeGenOptSizeAggressive, _) => {
 921             llvm::LLVMPassManagerBuilderUseInlinerWithThreshold(builder, 25);
 922         }
 923         (llvm::CodeGenOptLevel::None, ..) => {
 924             llvm::LLVMRustAddAlwaysInlinePass(builder, false);
 925         }
 926         (llvm::CodeGenOptLevel::Less, ..) => {
 927             llvm::LLVMRustAddAlwaysInlinePass(builder, true);
 928         }
 929         (llvm::CodeGenOptLevel::Default, ..) => {
 930             llvm::LLVMPassManagerBuilderUseInlinerWithThreshold(builder, 225);
 931         }
 932         (llvm::CodeGenOptLevel::Other, ..) => bug!("CodeGenOptLevel::Other selected"),
 933     }
 934
 935     f(builder);
 936     llvm::LLVMPassManagerBuilderDispose(builder);
 937 }
 938
 939 // Create a `__imp_<symbol> = &symbol` global for every public static `symbol`.
 940 // This is required to satisfy `dllimport` references to static data in .rlibs
 941 // when using MSVC linker.  We do this only for data, as linker can fix up
 942 // code references on its own.
 943 // See #26591, #27438
 944 fn create_msvc_imps(
 945     cgcx: &CodegenContext<LlvmCodegenBackend>,
 946     llcx: &llvm::Context,
 947     llmod: &llvm::Module,
 948 ) {
 949     if !cgcx.msvc_imps_needed {
 950         return;
 951     }
 952     // The x86 ABI seems to require that leading underscores are added to symbol
 953     // names, so we need an extra underscore on x86. There's also a leading
 954     // '\x01' here which disables LLVM's symbol mangling (e.g., no extra
 955     // underscores added in front).
 956     let prefix = if cgcx.target_arch == "x86" { "\x01__imp__" } else { "\x01__imp_" };
 957
 958     unsafe {
 959         let i8p_ty = Type::i8p_llcx(llcx);
 960         let globals = base::iter_globals(llmod)
 961             .filter(|&val| {
 962                 llvm::LLVMRustGetLinkage(val) == llvm::Linkage::ExternalLinkage
 963                     && llvm::LLVMIsDeclaration(val) == 0
 964             })
 965             .filter_map(|val| {
 966                 // Exclude some symbols that we know are not Rust symbols.
 967                 let name = llvm::get_value_name(val);
 968                 if ignored(name) { None } else { Some((val, name)) }
 969             })
 970             .map(move |(val, name)| {
 971                 let mut imp_name = prefix.as_bytes().to_vec();
 972                 imp_name.extend(name);
 973                 let imp_name = CString::new(imp_name).unwrap();
 974                 (imp_name, val)
 975             })
 976             .collect::<Vec<_>>();
 977
 978         for (imp_name, val) in globals {
 979             let imp = llvm::LLVMAddGlobal(llmod, i8p_ty, imp_name.as_ptr().cast());
 980             llvm::LLVMSetInitializer(imp, consts::ptrcast(val, i8p_ty));
 981             llvm::LLVMRustSetLinkage(imp, llvm::Linkage::ExternalLinkage);
 982         }
 983     }
 984
 985     // Use this function to exclude certain symbols from `__imp` generation.
 986     fn ignored(symbol_name: &[u8]) -> bool {
 987         // These are symbols generated by LLVM's profiling instrumentation
 988         symbol_name.starts_with(b"__llvm_profile_")
 989     }
 990 }