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1 // Copyright 2013-2015 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
4 //
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
10
11 use back::lto;
12 use back::link::{get_linker, remove};
13 use session::config::{OutputFilenames, Passes, SomePasses, AllPasses};
14 use session::Session;
15 use session::config::{self, OutputType};
16 use llvm;
17 use llvm::{ModuleRef, TargetMachineRef, PassManagerRef, DiagnosticInfoRef, ContextRef};
18 use llvm::SMDiagnosticRef;
19 use {CrateTranslation, ModuleTranslation};
20 use util::common::time;
21 use util::common::path2cstr;
22 use syntax::codemap;
23 use syntax::errors::{self, Handler, Level};
24 use syntax::errors::emitter::Emitter;
25
26 use std::collections::HashMap;
27 use std::ffi::{CStr, CString};
28 use std::fs;
29 use std::path::{Path, PathBuf};
30 use std::str;
31 use std::sync::{Arc, Mutex};
32 use std::sync::mpsc::channel;
33 use std::thread;
34 use libc::{c_uint, c_int, c_void};
35
36 pub fn llvm_err(handler: &errors::Handler, msg: String) -> ! {
37 match llvm::last_error() {
38 Some(err) => panic!(handler.fatal(&format!("{}: {}", msg, err))),
39 None => panic!(handler.fatal(&msg)),
40 }
41 }
42
43 pub fn write_output_file(
44 handler: &errors::Handler,
45 target: llvm::TargetMachineRef,
46 pm: llvm::PassManagerRef,
47 m: ModuleRef,
48 output: &Path,
49 file_type: llvm::FileType) {
50 unsafe {
51 let output_c = path2cstr(output);
52 let result = llvm::LLVMRustWriteOutputFile(
53 target, pm, m, output_c.as_ptr(), file_type);
54 if !result {
55 llvm_err(handler, format!("could not write output to {}", output.display()));
56 }
57 }
58 }
59
60
61 struct Diagnostic {
62 msg: String,
63 code: Option<String>,
64 lvl: Level,
65 }
66
67 // We use an Arc instead of just returning a list of diagnostics from the
68 // child thread because we need to make sure that the messages are seen even
69 // if the child thread panics (for example, when `fatal` is called).
70 #[derive(Clone)]
71 struct SharedEmitter {
72 buffer: Arc<Mutex<Vec<Diagnostic>>>,
73 }
74
75 impl SharedEmitter {
76 fn new() -> SharedEmitter {
77 SharedEmitter {
78 buffer: Arc::new(Mutex::new(Vec::new())),
79 }
80 }
81
82 fn dump(&mut self, handler: &Handler) {
83 let mut buffer = self.buffer.lock().unwrap();
84 for diag in &*buffer {
85 match diag.code {
86 Some(ref code) => {
87 handler.emit_with_code(None,
88 &diag.msg,
89 &code[..],
90 diag.lvl);
91 },
92 None => {
93 handler.emit(None,
94 &diag.msg,
95 diag.lvl);
96 },
97 }
98 }
99 buffer.clear();
100 }
101 }
102
103 impl Emitter for SharedEmitter {
104 fn emit(&mut self, sp: Option<&codemap::MultiSpan>,
105 msg: &str, code: Option<&str>, lvl: Level) {
106 assert!(sp.is_none(), "SharedEmitter doesn't support spans");
107
108 self.buffer.lock().unwrap().push(Diagnostic {
109 msg: msg.to_string(),
110 code: code.map(|s| s.to_string()),
111 lvl: lvl,
112 });
113 }
114
115 fn custom_emit(&mut self, _sp: &errors::RenderSpan, _msg: &str, _lvl: Level) {
116 bug!("SharedEmitter doesn't support custom_emit");
117 }
118 }
119
120
121 // On android, we by default compile for armv7 processors. This enables
122 // things like double word CAS instructions (rather than emulating them)
123 // which are *far* more efficient. This is obviously undesirable in some
124 // cases, so if any sort of target feature is specified we don't append v7
125 // to the feature list.
126 //
127 // On iOS only armv7 and newer are supported. So it is useful to
128 // get all hardware potential via VFP3 (hardware floating point)
129 // and NEON (SIMD) instructions supported by LLVM.
130 // Note that without those flags various linking errors might
131 // arise as some of intrinsics are converted into function calls
132 // and nobody provides implementations those functions
133 fn target_feature(sess: &Session) -> String {
134 format!("{},{}", sess.target.target.options.features, sess.opts.cg.target_feature)
135 }
136
137 fn get_llvm_opt_level(optimize: config::OptLevel) -> llvm::CodeGenOptLevel {
138 match optimize {
139 config::OptLevel::No => llvm::CodeGenLevelNone,
140 config::OptLevel::Less => llvm::CodeGenLevelLess,
141 config::OptLevel::Default => llvm::CodeGenLevelDefault,
142 config::OptLevel::Aggressive => llvm::CodeGenLevelAggressive,
143 }
144 }
145
146 pub fn create_target_machine(sess: &Session) -> TargetMachineRef {
147 let reloc_model_arg = match sess.opts.cg.relocation_model {
148 Some(ref s) => &s[..],
149 None => &sess.target.target.options.relocation_model[..],
150 };
151 let reloc_model = match reloc_model_arg {
152 "pic" => llvm::RelocPIC,
153 "static" => llvm::RelocStatic,
154 "default" => llvm::RelocDefault,
155 "dynamic-no-pic" => llvm::RelocDynamicNoPic,
156 _ => {
157 sess.err(&format!("{:?} is not a valid relocation mode",
158 sess.opts
159 .cg
160 .relocation_model));
161 sess.abort_if_errors();
162 bug!();
163 }
164 };
165
166 let opt_level = get_llvm_opt_level(sess.opts.optimize);
167 let use_softfp = sess.opts.cg.soft_float;
168
169 let any_library = sess.crate_types.borrow().iter().any(|ty| {
170 *ty != config::CrateTypeExecutable
171 });
172
173 let ffunction_sections = sess.target.target.options.function_sections;
174 let fdata_sections = ffunction_sections;
175
176 let code_model_arg = match sess.opts.cg.code_model {
177 Some(ref s) => &s[..],
178 None => &sess.target.target.options.code_model[..],
179 };
180
181 let code_model = match code_model_arg {
182 "default" => llvm::CodeModelDefault,
183 "small" => llvm::CodeModelSmall,
184 "kernel" => llvm::CodeModelKernel,
185 "medium" => llvm::CodeModelMedium,
186 "large" => llvm::CodeModelLarge,
187 _ => {
188 sess.err(&format!("{:?} is not a valid code model",
189 sess.opts
190 .cg
191 .code_model));
192 sess.abort_if_errors();
193 bug!();
194 }
195 };
196
197 let triple = &sess.target.target.llvm_target;
198
199 let tm = unsafe {
200 let triple = CString::new(triple.as_bytes()).unwrap();
201 let cpu = match sess.opts.cg.target_cpu {
202 Some(ref s) => &**s,
203 None => &*sess.target.target.options.cpu
204 };
205 let cpu = CString::new(cpu.as_bytes()).unwrap();
206 let features = CString::new(target_feature(sess).as_bytes()).unwrap();
207 llvm::LLVMRustCreateTargetMachine(
208 triple.as_ptr(), cpu.as_ptr(), features.as_ptr(),
209 code_model,
210 reloc_model,
211 opt_level,
212 use_softfp,
213 !any_library && reloc_model == llvm::RelocPIC,
214 ffunction_sections,
215 fdata_sections,
216 )
217 };
218
219 if tm.is_null() {
220 llvm_err(sess.diagnostic(),
221 format!("Could not create LLVM TargetMachine for triple: {}",
222 triple).to_string());
223 } else {
224 return tm;
225 };
226 }
227
228
229 /// Module-specific configuration for `optimize_and_codegen`.
230 #[derive(Clone)]
231 pub struct ModuleConfig {
232 /// LLVM TargetMachine to use for codegen.
233 tm: TargetMachineRef,
234 /// Names of additional optimization passes to run.
235 passes: Vec<String>,
236 /// Some(level) to optimize at a certain level, or None to run
237 /// absolutely no optimizations (used for the metadata module).
238 opt_level: Option<llvm::CodeGenOptLevel>,
239
240 // Flags indicating which outputs to produce.
241 emit_no_opt_bc: bool,
242 emit_bc: bool,
243 emit_lto_bc: bool,
244 emit_ir: bool,
245 emit_asm: bool,
246 emit_obj: bool,
247 // Miscellaneous flags. These are mostly copied from command-line
248 // options.
249 no_verify: bool,
250 no_prepopulate_passes: bool,
251 no_builtins: bool,
252 time_passes: bool,
253 vectorize_loop: bool,
254 vectorize_slp: bool,
255 merge_functions: bool,
256 inline_threshold: Option<usize>,
257 // Instead of creating an object file by doing LLVM codegen, just
258 // make the object file bitcode. Provides easy compatibility with
259 // emscripten's ecc compiler, when used as the linker.
260 obj_is_bitcode: bool,
261 }
262
263 unsafe impl Send for ModuleConfig { }
264
265 impl ModuleConfig {
266 fn new(tm: TargetMachineRef, passes: Vec<String>) -> ModuleConfig {
267 ModuleConfig {
268 tm: tm,
269 passes: passes,
270 opt_level: None,
271
272 emit_no_opt_bc: false,
273 emit_bc: false,
274 emit_lto_bc: false,
275 emit_ir: false,
276 emit_asm: false,
277 emit_obj: false,
278 obj_is_bitcode: false,
279
280 no_verify: false,
281 no_prepopulate_passes: false,
282 no_builtins: false,
283 time_passes: false,
284 vectorize_loop: false,
285 vectorize_slp: false,
286 merge_functions: false,
287 inline_threshold: None
288 }
289 }
290
291 fn set_flags(&mut self, sess: &Session, trans: &CrateTranslation) {
292 self.no_verify = sess.no_verify();
293 self.no_prepopulate_passes = sess.opts.cg.no_prepopulate_passes;
294 self.no_builtins = trans.no_builtins;
295 self.time_passes = sess.time_passes();
296 self.inline_threshold = sess.opts.cg.inline_threshold;
297 self.obj_is_bitcode = sess.target.target.options.obj_is_bitcode;
298
299 // Copy what clang does by turning on loop vectorization at O2 and
300 // slp vectorization at O3. Otherwise configure other optimization aspects
301 // of this pass manager builder.
302 self.vectorize_loop = !sess.opts.cg.no_vectorize_loops &&
303 (sess.opts.optimize == config::OptLevel::Default ||
304 sess.opts.optimize == config::OptLevel::Aggressive);
305 self.vectorize_slp = !sess.opts.cg.no_vectorize_slp &&
306 sess.opts.optimize == config::OptLevel::Aggressive;
307
308 self.merge_functions = sess.opts.optimize == config::OptLevel::Default ||
309 sess.opts.optimize == config::OptLevel::Aggressive;
310 }
311 }
312
313 /// Additional resources used by optimize_and_codegen (not module specific)
314 struct CodegenContext<'a> {
315 // Extra resources used for LTO: (sess, reachable). This will be `None`
316 // when running in a worker thread.
317 lto_ctxt: Option<(&'a Session, &'a [String])>,
318 // Handler to use for diagnostics produced during codegen.
319 handler: &'a Handler,
320 // LLVM passes added by plugins.
321 plugin_passes: Vec<String>,
322 // LLVM optimizations for which we want to print remarks.
323 remark: Passes,
324 // Worker thread number
325 worker: usize,
326 }
327
328 impl<'a> CodegenContext<'a> {
329 fn new_with_session(sess: &'a Session, reachable: &'a [String]) -> CodegenContext<'a> {
330 CodegenContext {
331 lto_ctxt: Some((sess, reachable)),
332 handler: sess.diagnostic(),
333 plugin_passes: sess.plugin_llvm_passes.borrow().clone(),
334 remark: sess.opts.cg.remark.clone(),
335 worker: 0,
336 }
337 }
338 }
339
340 struct HandlerFreeVars<'a> {
341 llcx: ContextRef,
342 cgcx: &'a CodegenContext<'a>,
343 }
344
345 unsafe extern "C" fn report_inline_asm<'a, 'b>(cgcx: &'a CodegenContext<'a>,
346 msg: &'b str,
347 cookie: c_uint) {
348 use syntax::codemap::ExpnId;
349
350 match cgcx.lto_ctxt {
351 Some((sess, _)) => {
352 sess.codemap().with_expn_info(ExpnId::from_u32(cookie), |info| match info {
353 Some(ei) => sess.span_err(ei.call_site, msg),
354 None => sess.err(msg),
355 });
356 }
357
358 None => {
359 cgcx.handler.struct_err(msg)
360 .note("build without -C codegen-units for more exact errors")
361 .emit();
362 }
363 }
364 }
365
366 unsafe extern "C" fn inline_asm_handler(diag: SMDiagnosticRef,
367 user: *const c_void,
368 cookie: c_uint) {
369 let HandlerFreeVars { cgcx, .. } = *(user as *const HandlerFreeVars);
370
371 let msg = llvm::build_string(|s| llvm::LLVMWriteSMDiagnosticToString(diag, s))
372 .expect("non-UTF8 SMDiagnostic");
373
374 report_inline_asm(cgcx, &msg[..], cookie);
375 }
376
377 unsafe extern "C" fn diagnostic_handler(info: DiagnosticInfoRef, user: *mut c_void) {
378 let HandlerFreeVars { llcx, cgcx } = *(user as *const HandlerFreeVars);
379
380 match llvm::diagnostic::Diagnostic::unpack(info) {
381 llvm::diagnostic::InlineAsm(inline) => {
382 report_inline_asm(cgcx,
383 &llvm::twine_to_string(inline.message),
384 inline.cookie);
385 }
386
387 llvm::diagnostic::Optimization(opt) => {
388 let pass_name = str::from_utf8(CStr::from_ptr(opt.pass_name).to_bytes())
389 .ok()
390 .expect("got a non-UTF8 pass name from LLVM");
391 let enabled = match cgcx.remark {
392 AllPasses => true,
393 SomePasses(ref v) => v.iter().any(|s| *s == pass_name),
394 };
395
396 if enabled {
397 let loc = llvm::debug_loc_to_string(llcx, opt.debug_loc);
398 cgcx.handler.note_without_error(&format!("optimization {} for {} at {}: {}",
399 opt.kind.describe(),
400 pass_name,
401 if loc.is_empty() { "[unknown]" } else { &*loc },
402 llvm::twine_to_string(opt.message)));
403 }
404 }
405
406 _ => (),
407 }
408 }
409
410 // Unsafe due to LLVM calls.
411 unsafe fn optimize_and_codegen(cgcx: &CodegenContext,
412 mtrans: ModuleTranslation,
413 config: ModuleConfig,
414 name_extra: String,
415 output_names: OutputFilenames) {
416 let ModuleTranslation { llmod, llcx } = mtrans;
417 let tm = config.tm;
418
419 // llcx doesn't outlive this function, so we can put this on the stack.
420 let fv = HandlerFreeVars {
421 llcx: llcx,
422 cgcx: cgcx,
423 };
424 let fv = &fv as *const HandlerFreeVars as *mut c_void;
425
426 llvm::LLVMSetInlineAsmDiagnosticHandler(llcx, inline_asm_handler, fv);
427 llvm::LLVMContextSetDiagnosticHandler(llcx, diagnostic_handler, fv);
428
429 if config.emit_no_opt_bc {
430 let ext = format!("{}.no-opt.bc", name_extra);
431 let out = output_names.with_extension(&ext);
432 let out = path2cstr(&out);
433 llvm::LLVMWriteBitcodeToFile(llmod, out.as_ptr());
434 }
435
436 if config.opt_level.is_some() {
437 // Create the two optimizing pass managers. These mirror what clang
438 // does, and are by populated by LLVM's default PassManagerBuilder.
439 // Each manager has a different set of passes, but they also share
440 // some common passes.
441 let fpm = llvm::LLVMCreateFunctionPassManagerForModule(llmod);
442 let mpm = llvm::LLVMCreatePassManager();
443
444 // If we're verifying or linting, add them to the function pass
445 // manager.
446 let addpass = |pass_name: &str| {
447 let pass_name = CString::new(pass_name).unwrap();
448 let pass = llvm::LLVMRustFindAndCreatePass(pass_name.as_ptr());
449 if pass.is_null() {
450 return false;
451 }
452 let pass_manager = match llvm::LLVMRustPassKind(pass) {
453 llvm::SupportedPassKind::Function => fpm,
454 llvm::SupportedPassKind::Module => mpm,
455 llvm::SupportedPassKind::Unsupported => {
456 cgcx.handler.err("Encountered LLVM pass kind we can't handle");
457 return true
458 },
459 };
460 llvm::LLVMRustAddPass(pass_manager, pass);
461 true
462 };
463
464 if !config.no_verify { assert!(addpass("verify")); }
465 if !config.no_prepopulate_passes {
466 llvm::LLVMRustAddAnalysisPasses(tm, fpm, llmod);
467 llvm::LLVMRustAddAnalysisPasses(tm, mpm, llmod);
468 with_llvm_pmb(llmod, &config, &mut |b| {
469 llvm::LLVMPassManagerBuilderPopulateFunctionPassManager(b, fpm);
470 llvm::LLVMPassManagerBuilderPopulateModulePassManager(b, mpm);
471 })
472 }
473
474 for pass in &config.passes {
475 if !addpass(pass) {
476 cgcx.handler.warn(&format!("unknown pass `{}`, ignoring",
477 pass));
478 }
479 }
480
481 for pass in &cgcx.plugin_passes {
482 if !addpass(pass) {
483 cgcx.handler.err(&format!("a plugin asked for LLVM pass \
484 `{}` but LLVM does not \
485 recognize it", pass));
486 }
487 }
488
489 cgcx.handler.abort_if_errors();
490
491 // Finally, run the actual optimization passes
492 time(config.time_passes, &format!("llvm function passes [{}]", cgcx.worker), ||
493 llvm::LLVMRustRunFunctionPassManager(fpm, llmod));
494 time(config.time_passes, &format!("llvm module passes [{}]", cgcx.worker), ||
495 llvm::LLVMRunPassManager(mpm, llmod));
496
497 // Deallocate managers that we're now done with
498 llvm::LLVMDisposePassManager(fpm);
499 llvm::LLVMDisposePassManager(mpm);
500
501 match cgcx.lto_ctxt {
502 Some((sess, reachable)) if sess.lto() => {
503 time(sess.time_passes(), "all lto passes", ||
504 lto::run(sess, llmod, tm, reachable, &config,
505 &name_extra, &output_names));
506
507 if config.emit_lto_bc {
508 let name = format!("{}.lto.bc", name_extra);
509 let out = output_names.with_extension(&name);
510 let out = path2cstr(&out);
511 llvm::LLVMWriteBitcodeToFile(llmod, out.as_ptr());
512 }
513 },
514 _ => {},
515 }
516 }
517
518 // A codegen-specific pass manager is used to generate object
519 // files for an LLVM module.
520 //
521 // Apparently each of these pass managers is a one-shot kind of
522 // thing, so we create a new one for each type of output. The
523 // pass manager passed to the closure should be ensured to not
524 // escape the closure itself, and the manager should only be
525 // used once.
526 unsafe fn with_codegen<F>(tm: TargetMachineRef,
527 llmod: ModuleRef,
528 no_builtins: bool,
529 f: F) where
530 F: FnOnce(PassManagerRef),
531 {
532 let cpm = llvm::LLVMCreatePassManager();
533 llvm::LLVMRustAddAnalysisPasses(tm, cpm, llmod);
534 llvm::LLVMRustAddLibraryInfo(cpm, llmod, no_builtins);
535 f(cpm);
536 }
537
538 // Change what we write and cleanup based on whether obj files are
539 // just llvm bitcode. In that case write bitcode, and possibly
540 // delete the bitcode if it wasn't requested. Don't generate the
541 // machine code, instead copy the .o file from the .bc
542 let write_bc = config.emit_bc || config.obj_is_bitcode;
543 let rm_bc = !config.emit_bc && config.obj_is_bitcode;
544 let write_obj = config.emit_obj && !config.obj_is_bitcode;
545 let copy_bc_to_obj = config.emit_obj && config.obj_is_bitcode;
546
547 let bc_out = output_names.with_extension(&format!("{}.bc", name_extra));
548 let obj_out = output_names.with_extension(&format!("{}.o", name_extra));
549
550 if write_bc {
551 let bc_out_c = path2cstr(&bc_out);
552 llvm::LLVMWriteBitcodeToFile(llmod, bc_out_c.as_ptr());
553 }
554
555 time(config.time_passes, &format!("codegen passes [{}]", cgcx.worker), || {
556 if config.emit_ir {
557 let ext = format!("{}.ll", name_extra);
558 let out = output_names.with_extension(&ext);
559 let out = path2cstr(&out);
560 with_codegen(tm, llmod, config.no_builtins, |cpm| {
561 llvm::LLVMRustPrintModule(cpm, llmod, out.as_ptr());
562 llvm::LLVMDisposePassManager(cpm);
563 })
564 }
565
566 if config.emit_asm {
567 let path = output_names.with_extension(&format!("{}.s", name_extra));
568
569 // We can't use the same module for asm and binary output, because that triggers
570 // various errors like invalid IR or broken binaries, so we might have to clone the
571 // module to produce the asm output
572 let llmod = if config.emit_obj {
573 llvm::LLVMCloneModule(llmod)
574 } else {
575 llmod
576 };
577 with_codegen(tm, llmod, config.no_builtins, |cpm| {
578 write_output_file(cgcx.handler, tm, cpm, llmod, &path,
579 llvm::AssemblyFileType);
580 });
581 if config.emit_obj {
582 llvm::LLVMDisposeModule(llmod);
583 }
584 }
585
586 if write_obj {
587 with_codegen(tm, llmod, config.no_builtins, |cpm| {
588 write_output_file(cgcx.handler, tm, cpm, llmod, &obj_out, llvm::ObjectFileType);
589 });
590 }
591 });
592
593 if copy_bc_to_obj {
594 debug!("copying bitcode {:?} to obj {:?}", bc_out, obj_out);
595 if let Err(e) = fs::copy(&bc_out, &obj_out) {
596 cgcx.handler.err(&format!("failed to copy bitcode to object file: {}", e));
597 }
598 }
599
600 if rm_bc {
601 debug!("removing_bitcode {:?}", bc_out);
602 if let Err(e) = fs::remove_file(&bc_out) {
603 cgcx.handler.err(&format!("failed to remove bitcode: {}", e));
604 }
605 }
606
607 llvm::LLVMDisposeModule(llmod);
608 llvm::LLVMContextDispose(llcx);
609 llvm::LLVMRustDisposeTargetMachine(tm);
610 }
611
612 pub fn run_passes(sess: &Session,
613 trans: &CrateTranslation,
614 output_types: &HashMap<OutputType, Option<PathBuf>>,
615 crate_output: &OutputFilenames) {
616 // It's possible that we have `codegen_units > 1` but only one item in
617 // `trans.modules`. We could theoretically proceed and do LTO in that
618 // case, but it would be confusing to have the validity of
619 // `-Z lto -C codegen-units=2` depend on details of the crate being
620 // compiled, so we complain regardless.
621 if sess.lto() && sess.opts.cg.codegen_units > 1 {
622 // This case is impossible to handle because LTO expects to be able
623 // to combine the entire crate and all its dependencies into a
624 // single compilation unit, but each codegen unit is in a separate
625 // LLVM context, so they can't easily be combined.
626 sess.fatal("can't perform LTO when using multiple codegen units");
627 }
628
629 // Sanity check
630 assert!(trans.modules.len() == sess.opts.cg.codegen_units);
631
632 let tm = create_target_machine(sess);
633
634 // Figure out what we actually need to build.
635
636 let mut modules_config = ModuleConfig::new(tm, sess.opts.cg.passes.clone());
637 let mut metadata_config = ModuleConfig::new(tm, vec!());
638
639 modules_config.opt_level = Some(get_llvm_opt_level(sess.opts.optimize));
640
641 // Save all versions of the bytecode if we're saving our temporaries.
642 if sess.opts.cg.save_temps {
643 modules_config.emit_no_opt_bc = true;
644 modules_config.emit_bc = true;
645 modules_config.emit_lto_bc = true;
646 metadata_config.emit_bc = true;
647 }
648
649 // Emit bitcode files for the crate if we're emitting an rlib.
650 // Whenever an rlib is created, the bitcode is inserted into the
651 // archive in order to allow LTO against it.
652 let needs_crate_bitcode =
653 sess.crate_types.borrow().contains(&config::CrateTypeRlib) &&
654 sess.opts.output_types.contains_key(&OutputType::Exe);
655 let needs_crate_object =
656 sess.opts.output_types.contains_key(&OutputType::Exe);
657 if needs_crate_bitcode {
658 modules_config.emit_bc = true;
659 }
660
661 for output_type in output_types.keys() {
662 match *output_type {
663 OutputType::Bitcode => { modules_config.emit_bc = true; },
664 OutputType::LlvmAssembly => { modules_config.emit_ir = true; },
665 OutputType::Assembly => {
666 modules_config.emit_asm = true;
667 // If we're not using the LLVM assembler, this function
668 // could be invoked specially with output_type_assembly, so
669 // in this case we still want the metadata object file.
670 if !sess.opts.output_types.contains_key(&OutputType::Assembly) {
671 metadata_config.emit_obj = true;
672 }
673 },
674 OutputType::Object => { modules_config.emit_obj = true; },
675 OutputType::Exe => {
676 modules_config.emit_obj = true;
677 metadata_config.emit_obj = true;
678 },
679 OutputType::DepInfo => {}
680 }
681 }
682
683 modules_config.set_flags(sess, trans);
684 metadata_config.set_flags(sess, trans);
685
686
687 // Populate a buffer with a list of codegen threads. Items are processed in
688 // LIFO order, just because it's a tiny bit simpler that way. (The order
689 // doesn't actually matter.)
690 let mut work_items = Vec::with_capacity(1 + trans.modules.len());
691
692 {
693 let work = build_work_item(sess,
694 trans.metadata_module,
695 metadata_config.clone(),
696 crate_output.clone(),
697 "metadata".to_string());
698 work_items.push(work);
699 }
700
701 for (index, mtrans) in trans.modules.iter().enumerate() {
702 let work = build_work_item(sess,
703 *mtrans,
704 modules_config.clone(),
705 crate_output.clone(),
706 format!("{}", index));
707 work_items.push(work);
708 }
709
710 // Process the work items, optionally using worker threads.
711 if sess.opts.cg.codegen_units == 1 {
712 run_work_singlethreaded(sess, &trans.reachable, work_items);
713 } else {
714 run_work_multithreaded(sess, work_items, sess.opts.cg.codegen_units);
715 }
716
717 // All codegen is finished.
718 unsafe {
719 llvm::LLVMRustDisposeTargetMachine(tm);
720 }
721
722 // Produce final compile outputs.
723 let copy_gracefully = |from: &Path, to: &Path| {
724 if let Err(e) = fs::copy(from, to) {
725 sess.err(&format!("could not copy {:?} to {:?}: {}", from, to, e));
726 }
727 };
728
729 let copy_if_one_unit = |ext: &str,
730 output_type: OutputType,
731 keep_numbered: bool| {
732 if sess.opts.cg.codegen_units == 1 {
733 // 1) Only one codegen unit. In this case it's no difficulty
734 // to copy `foo.0.x` to `foo.x`.
735 copy_gracefully(&crate_output.with_extension(ext),
736 &crate_output.path(output_type));
737 if !sess.opts.cg.save_temps && !keep_numbered {
738 // The user just wants `foo.x`, not `foo.0.x`.
739 remove(sess, &crate_output.with_extension(ext));
740 }
741 } else if crate_output.outputs.contains_key(&output_type) {
742 // 2) Multiple codegen units, with `--emit foo=some_name`. We have
743 // no good solution for this case, so warn the user.
744 sess.warn(&format!("ignoring emit path because multiple .{} files \
745 were produced", ext));
746 } else if crate_output.single_output_file.is_some() {
747 // 3) Multiple codegen units, with `-o some_name`. We have
748 // no good solution for this case, so warn the user.
749 sess.warn(&format!("ignoring -o because multiple .{} files \
750 were produced", ext));
751 } else {
752 // 4) Multiple codegen units, but no explicit name. We
753 // just leave the `foo.0.x` files in place.
754 // (We don't have to do any work in this case.)
755 }
756 };
757
758 // Flag to indicate whether the user explicitly requested bitcode.
759 // Otherwise, we produced it only as a temporary output, and will need
760 // to get rid of it.
761 let mut user_wants_bitcode = false;
762 let mut user_wants_objects = false;
763 for output_type in output_types.keys() {
764 match *output_type {
765 OutputType::Bitcode => {
766 user_wants_bitcode = true;
767 // Copy to .bc, but always keep the .0.bc. There is a later
768 // check to figure out if we should delete .0.bc files, or keep
769 // them for making an rlib.
770 copy_if_one_unit("0.bc", OutputType::Bitcode, true);
771 }
772 OutputType::LlvmAssembly => {
773 copy_if_one_unit("0.ll", OutputType::LlvmAssembly, false);
774 }
775 OutputType::Assembly => {
776 copy_if_one_unit("0.s", OutputType::Assembly, false);
777 }
778 OutputType::Object => {
779 user_wants_objects = true;
780 copy_if_one_unit("0.o", OutputType::Object, true);
781 }
782 OutputType::Exe |
783 OutputType::DepInfo => {}
784 }
785 }
786 let user_wants_bitcode = user_wants_bitcode;
787
788 // Clean up unwanted temporary files.
789
790 // We create the following files by default:
791 // - crate.0.bc
792 // - crate.0.o
793 // - crate.metadata.bc
794 // - crate.metadata.o
795 // - crate.o (linked from crate.##.o)
796 // - crate.bc (copied from crate.0.bc)
797 // We may create additional files if requested by the user (through
798 // `-C save-temps` or `--emit=` flags).
799
800 if !sess.opts.cg.save_temps {
801 // Remove the temporary .0.o objects. If the user didn't
802 // explicitly request bitcode (with --emit=bc), and the bitcode is not
803 // needed for building an rlib, then we must remove .0.bc as well.
804
805 // Specific rules for keeping .0.bc:
806 // - If we're building an rlib (`needs_crate_bitcode`), then keep
807 // it.
808 // - If the user requested bitcode (`user_wants_bitcode`), and
809 // codegen_units > 1, then keep it.
810 // - If the user requested bitcode but codegen_units == 1, then we
811 // can toss .0.bc because we copied it to .bc earlier.
812 // - If we're not building an rlib and the user didn't request
813 // bitcode, then delete .0.bc.
814 // If you change how this works, also update back::link::link_rlib,
815 // where .0.bc files are (maybe) deleted after making an rlib.
816 let keep_numbered_bitcode = needs_crate_bitcode ||
817 (user_wants_bitcode && sess.opts.cg.codegen_units > 1);
818
819 let keep_numbered_objects = needs_crate_object ||
820 (user_wants_objects && sess.opts.cg.codegen_units > 1);
821
822 for i in 0..trans.modules.len() {
823 if modules_config.emit_obj && !keep_numbered_objects {
824 let ext = format!("{}.o", i);
825 remove(sess, &crate_output.with_extension(&ext));
826 }
827
828 if modules_config.emit_bc && !keep_numbered_bitcode {
829 let ext = format!("{}.bc", i);
830 remove(sess, &crate_output.with_extension(&ext));
831 }
832 }
833
834 if metadata_config.emit_bc && !user_wants_bitcode {
835 remove(sess, &crate_output.with_extension("metadata.bc"));
836 }
837 }
838
839 // We leave the following files around by default:
840 // - crate.o
841 // - crate.metadata.o
842 // - crate.bc
843 // These are used in linking steps and will be cleaned up afterward.
844
845 // FIXME: time_llvm_passes support - does this use a global context or
846 // something?
847 if sess.opts.cg.codegen_units == 1 && sess.time_llvm_passes() {
848 unsafe { llvm::LLVMRustPrintPassTimings(); }
849 }
850 }
851
852 struct WorkItem {
853 mtrans: ModuleTranslation,
854 config: ModuleConfig,
855 output_names: OutputFilenames,
856 name_extra: String
857 }
858
859 fn build_work_item(sess: &Session,
860 mtrans: ModuleTranslation,
861 config: ModuleConfig,
862 output_names: OutputFilenames,
863 name_extra: String)
864 -> WorkItem
865 {
866 let mut config = config;
867 config.tm = create_target_machine(sess);
868 WorkItem { mtrans: mtrans, config: config, output_names: output_names,
869 name_extra: name_extra }
870 }
871
872 fn execute_work_item(cgcx: &CodegenContext,
873 work_item: WorkItem) {
874 unsafe {
875 optimize_and_codegen(cgcx, work_item.mtrans, work_item.config,
876 work_item.name_extra, work_item.output_names);
877 }
878 }
879
880 fn run_work_singlethreaded(sess: &Session,
881 reachable: &[String],
882 work_items: Vec<WorkItem>) {
883 let cgcx = CodegenContext::new_with_session(sess, reachable);
884
885 // Since we're running single-threaded, we can pass the session to
886 // the proc, allowing `optimize_and_codegen` to perform LTO.
887 for work in work_items.into_iter().rev() {
888 execute_work_item(&cgcx, work);
889 }
890 }
891
892 fn run_work_multithreaded(sess: &Session,
893 work_items: Vec<WorkItem>,
894 num_workers: usize) {
895 // Run some workers to process the work items.
896 let work_items_arc = Arc::new(Mutex::new(work_items));
897 let mut diag_emitter = SharedEmitter::new();
898 let mut futures = Vec::with_capacity(num_workers);
899
900 for i in 0..num_workers {
901 let work_items_arc = work_items_arc.clone();
902 let diag_emitter = diag_emitter.clone();
903 let plugin_passes = sess.plugin_llvm_passes.borrow().clone();
904 let remark = sess.opts.cg.remark.clone();
905
906 let (tx, rx) = channel();
907 let mut tx = Some(tx);
908 futures.push(rx);
909
910 thread::Builder::new().name(format!("codegen-{}", i)).spawn(move || {
911 let diag_handler = Handler::with_emitter(true, false, box diag_emitter);
912
913 // Must construct cgcx inside the proc because it has non-Send
914 // fields.
915 let cgcx = CodegenContext {
916 lto_ctxt: None,
917 handler: &diag_handler,
918 plugin_passes: plugin_passes,
919 remark: remark,
920 worker: i,
921 };
922
923 loop {
924 // Avoid holding the lock for the entire duration of the match.
925 let maybe_work = work_items_arc.lock().unwrap().pop();
926 match maybe_work {
927 Some(work) => {
928 execute_work_item(&cgcx, work);
929
930 // Make sure to fail the worker so the main thread can
931 // tell that there were errors.
932 cgcx.handler.abort_if_errors();
933 }
934 None => break,
935 }
936 }
937
938 tx.take().unwrap().send(()).unwrap();
939 }).unwrap();
940 }
941
942 let mut panicked = false;
943 for rx in futures {
944 match rx.recv() {
945 Ok(()) => {},
946 Err(_) => {
947 panicked = true;
948 },
949 }
950 // Display any new diagnostics.
951 diag_emitter.dump(sess.diagnostic());
952 }
953 if panicked {
954 sess.fatal("aborting due to worker thread panic");
955 }
956 }
957
958 pub fn run_assembler(sess: &Session, outputs: &OutputFilenames) {
959 let (pname, mut cmd) = get_linker(sess);
960
961 cmd.arg("-c").arg("-o").arg(&outputs.path(OutputType::Object))
962 .arg(&outputs.temp_path(OutputType::Assembly));
963 debug!("{:?}", cmd);
964
965 match cmd.output() {
966 Ok(prog) => {
967 if !prog.status.success() {
968 let mut note = prog.stderr.clone();
969 note.extend_from_slice(&prog.stdout);
970
971 sess.struct_err(&format!("linking with `{}` failed: {}",
972 pname,
973 prog.status))
974 .note(&format!("{:?}", &cmd))
975 .note(str::from_utf8(&note[..]).unwrap())
976 .emit();
977 sess.abort_if_errors();
978 }
979 },
980 Err(e) => {
981 sess.err(&format!("could not exec the linker `{}`: {}", pname, e));
982 sess.abort_if_errors();
983 }
984 }
985 }
986
987 pub unsafe fn configure_llvm(sess: &Session) {
988 let mut llvm_c_strs = Vec::new();
989 let mut llvm_args = Vec::new();
990
991 {
992 let mut add = |arg: &str| {
993 let s = CString::new(arg).unwrap();
994 llvm_args.push(s.as_ptr());
995 llvm_c_strs.push(s);
996 };
997 add("rustc"); // fake program name
998 if sess.time_llvm_passes() { add("-time-passes"); }
999 if sess.print_llvm_passes() { add("-debug-pass=Structure"); }
1000
1001 // FIXME #21627 disable faulty FastISel on AArch64 (even for -O0)
1002 if sess.target.target.arch == "aarch64" { add("-fast-isel=0"); }
1003
1004 for arg in &sess.opts.cg.llvm_args {
1005 add(&(*arg));
1006 }
1007 }
1008
1009 llvm::LLVMInitializePasses();
1010
1011 llvm::initialize_available_targets();
1012
1013 llvm::LLVMRustSetLLVMOptions(llvm_args.len() as c_int,
1014 llvm_args.as_ptr());
1015 }
1016
1017 pub unsafe fn with_llvm_pmb(llmod: ModuleRef,
1018 config: &ModuleConfig,
1019 f: &mut FnMut(llvm::PassManagerBuilderRef)) {
1020 // Create the PassManagerBuilder for LLVM. We configure it with
1021 // reasonable defaults and prepare it to actually populate the pass
1022 // manager.
1023 let builder = llvm::LLVMPassManagerBuilderCreate();
1024 let opt = config.opt_level.unwrap_or(llvm::CodeGenLevelNone);
1025 let inline_threshold = config.inline_threshold;
1026
1027 llvm::LLVMRustConfigurePassManagerBuilder(builder, opt,
1028 config.merge_functions,
1029 config.vectorize_slp,
1030 config.vectorize_loop);
1031
1032 llvm::LLVMRustAddBuilderLibraryInfo(builder, llmod, config.no_builtins);
1033
1034 // Here we match what clang does (kinda). For O0 we only inline
1035 // always-inline functions (but don't add lifetime intrinsics), at O1 we
1036 // inline with lifetime intrinsics, and O2+ we add an inliner with a
1037 // thresholds copied from clang.
1038 match (opt, inline_threshold) {
1039 (_, Some(t)) => {
1040 llvm::LLVMPassManagerBuilderUseInlinerWithThreshold(builder, t as u32);
1041 }
1042 (llvm::CodeGenLevelNone, _) => {
1043 llvm::LLVMRustAddAlwaysInlinePass(builder, false);
1044 }
1045 (llvm::CodeGenLevelLess, _) => {
1046 llvm::LLVMRustAddAlwaysInlinePass(builder, true);
1047 }
1048 (llvm::CodeGenLevelDefault, _) => {
1049 llvm::LLVMPassManagerBuilderUseInlinerWithThreshold(builder, 225);
1050 }
1051 (llvm::CodeGenLevelAggressive, _) => {
1052 llvm::LLVMPassManagerBuilderUseInlinerWithThreshold(builder, 275);
1053 }
1054 }
1055
1056 f(builder);
1057 llvm::LLVMPassManagerBuilderDispose(builder);
1058 }