1 // Copyright 2012-2014 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.
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.
11 use super::archive::{Archive, ArchiveConfig, METADATA_FILENAME};
13 use super::rpath::RPathConfig;
15 use driver::driver::{CrateTranslation, OutputFilenames, Input, FileInput};
16 use driver::config::NoDebugInfo;
17 use driver::session::Session;
21 use metadata::common::LinkMeta;
22 use metadata::{encoder, cstore, filesearch, csearch, loader, creader};
23 use middle::trans::context::CrateContext;
24 use middle::trans::common::gensym_name;
26 use util::common::time;
28 use util::sha2::{Digest, Sha256};
30 use std::c_str::{ToCStr, CString};
32 use std::collections::HashSet;
33 use std::io::{fs, TempDir, Command};
37 use std::string::String;
39 use serialize::hex::ToHex;
42 use syntax::ast_map::{PathElem, PathElems, PathName};
44 use syntax::attr::AttrMetaMethods;
45 use syntax::codemap::Span;
46 use syntax::parse::token;
48 #[deriving(Clone, PartialEq, PartialOrd, Ord, Eq)]
52 OutputTypeLlvmAssembly,
57 pub fn llvm_err(sess: &Session, msg: String) -> ! {
59 let cstr = llvm::LLVMRustGetLastError();
60 if cstr == ptr::null() {
61 sess.fatal(msg.as_slice());
63 let err = CString::new(cstr, true);
64 let err = String::from_utf8_lossy(err.as_bytes());
65 sess.fatal(format!("{}: {}",
67 err.as_slice()).as_slice());
72 pub fn write_output_file(
74 target: llvm::TargetMachineRef,
75 pm: llvm::PassManagerRef,
78 file_type: llvm::FileType) {
80 output.with_c_str(|output| {
81 let result = llvm::LLVMRustWriteOutputFile(
82 target, pm, m, output, file_type);
84 llvm_err(sess, "could not write output".to_string());
92 use super::super::lto;
93 use super::{write_output_file, OutputType};
94 use super::{OutputTypeAssembly, OutputTypeBitcode};
95 use super::{OutputTypeExe, OutputTypeLlvmAssembly};
96 use super::{OutputTypeObject};
97 use driver::driver::{CrateTranslation, OutputFilenames};
98 use driver::config::NoDebugInfo;
99 use driver::session::Session;
102 use llvm::{ModuleRef, TargetMachineRef, PassManagerRef};
103 use util::common::time;
106 use std::c_str::ToCStr;
107 use std::io::{Command};
108 use libc::{c_uint, c_int};
111 // On android, we by default compile for armv7 processors. This enables
112 // things like double word CAS instructions (rather than emulating them)
113 // which are *far* more efficient. This is obviously undesirable in some
114 // cases, so if any sort of target feature is specified we don't append v7
115 // to the feature list.
117 // On iOS only armv7 and newer are supported. So it is useful to
118 // get all hardware potential via VFP3 (hardware floating point)
119 // and NEON (SIMD) instructions supported by LLVM.
120 // Note that without those flags various linking errors might
121 // arise as some of intrinsics are converted into function calls
122 // and nobody provides implementations those functions
123 fn target_feature<'a>(sess: &'a Session) -> &'a str {
124 match sess.targ_cfg.os {
126 if "" == sess.opts.cg.target_feature.as_slice() {
129 sess.opts.cg.target_feature.as_slice()
132 abi::OsiOS if sess.targ_cfg.arch == abi::Arm => {
133 "+v7,+thumb2,+vfp3,+neon"
135 _ => sess.opts.cg.target_feature.as_slice()
139 pub fn run_passes(sess: &Session,
140 trans: &CrateTranslation,
141 output_types: &[OutputType],
142 output: &OutputFilenames) {
143 let llmod = trans.module;
144 let llcx = trans.context;
146 configure_llvm(sess);
148 if sess.opts.cg.save_temps {
149 output.with_extension("no-opt.bc").with_c_str(|buf| {
150 llvm::LLVMWriteBitcodeToFile(llmod, buf);
154 let opt_level = match sess.opts.optimize {
155 config::No => llvm::CodeGenLevelNone,
156 config::Less => llvm::CodeGenLevelLess,
157 config::Default => llvm::CodeGenLevelDefault,
158 config::Aggressive => llvm::CodeGenLevelAggressive,
160 let use_softfp = sess.opts.cg.soft_float;
162 // FIXME: #11906: Omitting frame pointers breaks retrieving the value of a parameter.
163 // FIXME: #11954: mac64 unwinding may not work with fp elim
164 let no_fp_elim = (sess.opts.debuginfo != NoDebugInfo) ||
165 (sess.targ_cfg.os == abi::OsMacos &&
166 sess.targ_cfg.arch == abi::X86_64);
168 // OSX has -dead_strip, which doesn't rely on ffunction_sections
169 // FIXME(#13846) this should be enabled for windows
170 let ffunction_sections = sess.targ_cfg.os != abi::OsMacos &&
171 sess.targ_cfg.os != abi::OsWin32;
172 let fdata_sections = ffunction_sections;
174 let reloc_model = match sess.opts.cg.relocation_model.as_slice() {
175 "pic" => llvm::RelocPIC,
176 "static" => llvm::RelocStatic,
177 "default" => llvm::RelocDefault,
178 "dynamic-no-pic" => llvm::RelocDynamicNoPic,
180 sess.err(format!("{} is not a valid relocation mode",
183 .relocation_model).as_slice());
184 sess.abort_if_errors();
189 let code_model = match sess.opts.cg.code_model.as_slice() {
190 "default" => llvm::CodeModelDefault,
191 "small" => llvm::CodeModelSmall,
192 "kernel" => llvm::CodeModelKernel,
193 "medium" => llvm::CodeModelMedium,
194 "large" => llvm::CodeModelLarge,
196 sess.err(format!("{} is not a valid code model",
199 .code_model).as_slice());
200 sess.abort_if_errors();
205 let tm = sess.targ_cfg
210 sess.opts.cg.target_cpu.as_slice().with_c_str(|cpu| {
211 target_feature(sess).with_c_str(|features| {
212 llvm::LLVMRustCreateTargetMachine(
217 true /* EnableSegstk */,
227 // Create the two optimizing pass managers. These mirror what clang
228 // does, and are by populated by LLVM's default PassManagerBuilder.
229 // Each manager has a different set of passes, but they also share
230 // some common passes.
231 let fpm = llvm::LLVMCreateFunctionPassManagerForModule(llmod);
232 let mpm = llvm::LLVMCreatePassManager();
234 // If we're verifying or linting, add them to the function pass
236 let addpass = |pass: &str| {
237 pass.as_slice().with_c_str(|s| llvm::LLVMRustAddPass(fpm, s))
239 if !sess.no_verify() { assert!(addpass("verify")); }
241 if !sess.opts.cg.no_prepopulate_passes {
242 llvm::LLVMRustAddAnalysisPasses(tm, fpm, llmod);
243 llvm::LLVMRustAddAnalysisPasses(tm, mpm, llmod);
244 populate_llvm_passes(fpm, mpm, llmod, opt_level,
248 for pass in sess.opts.cg.passes.iter() {
249 pass.as_slice().with_c_str(|s| {
250 if !llvm::LLVMRustAddPass(mpm, s) {
251 sess.warn(format!("unknown pass {}, ignoring",
257 // Finally, run the actual optimization passes
258 time(sess.time_passes(), "llvm function passes", (), |()|
259 llvm::LLVMRustRunFunctionPassManager(fpm, llmod));
260 time(sess.time_passes(), "llvm module passes", (), |()|
261 llvm::LLVMRunPassManager(mpm, llmod));
263 // Deallocate managers that we're now done with
264 llvm::LLVMDisposePassManager(fpm);
265 llvm::LLVMDisposePassManager(mpm);
267 // Emit the bytecode if we're either saving our temporaries or
268 // emitting an rlib. Whenever an rlib is created, the bytecode is
269 // inserted into the archive in order to allow LTO against it.
270 if sess.opts.cg.save_temps ||
271 (sess.crate_types.borrow().contains(&config::CrateTypeRlib) &&
272 sess.opts.output_types.contains(&OutputTypeExe)) {
273 output.temp_path(OutputTypeBitcode).with_c_str(|buf| {
274 llvm::LLVMWriteBitcodeToFile(llmod, buf);
279 time(sess.time_passes(), "all lto passes", (), |()|
280 lto::run(sess, llmod, tm, trans.reachable.as_slice()));
282 if sess.opts.cg.save_temps {
283 output.with_extension("lto.bc").with_c_str(|buf| {
284 llvm::LLVMWriteBitcodeToFile(llmod, buf);
289 // A codegen-specific pass manager is used to generate object
290 // files for an LLVM module.
292 // Apparently each of these pass managers is a one-shot kind of
293 // thing, so we create a new one for each type of output. The
294 // pass manager passed to the closure should be ensured to not
295 // escape the closure itself, and the manager should only be
297 fn with_codegen(tm: TargetMachineRef, llmod: ModuleRef,
298 no_builtins: bool, f: |PassManagerRef|) {
300 let cpm = llvm::LLVMCreatePassManager();
301 llvm::LLVMRustAddAnalysisPasses(tm, cpm, llmod);
302 llvm::LLVMRustAddLibraryInfo(cpm, llmod, no_builtins);
304 llvm::LLVMDisposePassManager(cpm);
308 let mut object_file = None;
309 let mut needs_metadata = false;
310 for output_type in output_types.iter() {
311 let path = output.path(*output_type);
313 OutputTypeBitcode => {
314 path.with_c_str(|buf| {
315 llvm::LLVMWriteBitcodeToFile(llmod, buf);
318 OutputTypeLlvmAssembly => {
319 path.with_c_str(|output| {
320 with_codegen(tm, llmod, trans.no_builtins, |cpm| {
321 llvm::LLVMRustPrintModule(cpm, llmod, output);
325 OutputTypeAssembly => {
326 // If we're not using the LLVM assembler, this function
327 // could be invoked specially with output_type_assembly,
328 // so in this case we still want the metadata object
330 let ty = OutputTypeAssembly;
331 let path = if sess.opts.output_types.contains(&ty) {
334 needs_metadata = true;
335 output.temp_path(OutputTypeAssembly)
337 with_codegen(tm, llmod, trans.no_builtins, |cpm| {
338 write_output_file(sess, tm, cpm, llmod, &path,
342 OutputTypeObject => {
343 object_file = Some(path);
346 object_file = Some(output.temp_path(OutputTypeObject));
347 needs_metadata = true;
352 time(sess.time_passes(), "codegen passes", (), |()| {
355 with_codegen(tm, llmod, trans.no_builtins, |cpm| {
356 write_output_file(sess, tm, cpm, llmod, path,
363 with_codegen(tm, trans.metadata_module,
364 trans.no_builtins, |cpm| {
365 let out = output.temp_path(OutputTypeObject)
366 .with_extension("metadata.o");
367 write_output_file(sess, tm, cpm,
368 trans.metadata_module, &out,
374 llvm::LLVMRustDisposeTargetMachine(tm);
375 llvm::LLVMDisposeModule(trans.metadata_module);
376 llvm::LLVMDisposeModule(llmod);
377 llvm::LLVMContextDispose(llcx);
378 if sess.time_llvm_passes() { llvm::LLVMRustPrintPassTimings(); }
382 pub fn run_assembler(sess: &Session, outputs: &OutputFilenames) {
383 let pname = super::get_cc_prog(sess);
384 let mut cmd = Command::new(pname.as_slice());
386 cmd.arg("-c").arg("-o").arg(outputs.path(OutputTypeObject))
387 .arg(outputs.temp_path(OutputTypeAssembly));
392 if !prog.status.success() {
393 sess.err(format!("linking with `{}` failed: {}",
395 prog.status).as_slice());
396 sess.note(format!("{}", &cmd).as_slice());
397 let mut note = prog.error.clone();
398 note.push_all(prog.output.as_slice());
399 sess.note(str::from_utf8(note.as_slice()).unwrap());
400 sess.abort_if_errors();
404 sess.err(format!("could not exec the linker `{}`: {}",
407 sess.abort_if_errors();
412 unsafe fn configure_llvm(sess: &Session) {
413 use std::sync::{Once, ONCE_INIT};
414 static mut INIT: Once = ONCE_INIT;
416 // Copy what clang does by turning on loop vectorization at O2 and
417 // slp vectorization at O3
418 let vectorize_loop = !sess.opts.cg.no_vectorize_loops &&
419 (sess.opts.optimize == config::Default ||
420 sess.opts.optimize == config::Aggressive);
421 let vectorize_slp = !sess.opts.cg.no_vectorize_slp &&
422 sess.opts.optimize == config::Aggressive;
424 let mut llvm_c_strs = Vec::new();
425 let mut llvm_args = Vec::new();
427 let add = |arg: &str| {
428 let s = arg.to_c_str();
429 llvm_args.push(s.as_ptr());
432 add("rustc"); // fake program name
433 if vectorize_loop { add("-vectorize-loops"); }
434 if vectorize_slp { add("-vectorize-slp"); }
435 if sess.time_llvm_passes() { add("-time-passes"); }
436 if sess.print_llvm_passes() { add("-debug-pass=Structure"); }
438 for arg in sess.opts.cg.llvm_args.iter() {
439 add((*arg).as_slice());
444 llvm::LLVMInitializePasses();
446 // Only initialize the platforms supported by Rust here, because
447 // using --llvm-root will have multiple platforms that rustllvm
448 // doesn't actually link to and it's pointless to put target info
449 // into the registry that Rust cannot generate machine code for.
450 llvm::LLVMInitializeX86TargetInfo();
451 llvm::LLVMInitializeX86Target();
452 llvm::LLVMInitializeX86TargetMC();
453 llvm::LLVMInitializeX86AsmPrinter();
454 llvm::LLVMInitializeX86AsmParser();
456 llvm::LLVMInitializeARMTargetInfo();
457 llvm::LLVMInitializeARMTarget();
458 llvm::LLVMInitializeARMTargetMC();
459 llvm::LLVMInitializeARMAsmPrinter();
460 llvm::LLVMInitializeARMAsmParser();
462 llvm::LLVMInitializeMipsTargetInfo();
463 llvm::LLVMInitializeMipsTarget();
464 llvm::LLVMInitializeMipsTargetMC();
465 llvm::LLVMInitializeMipsAsmPrinter();
466 llvm::LLVMInitializeMipsAsmParser();
468 llvm::LLVMRustSetLLVMOptions(llvm_args.len() as c_int,
473 unsafe fn populate_llvm_passes(fpm: llvm::PassManagerRef,
474 mpm: llvm::PassManagerRef,
476 opt: llvm::CodeGenOptLevel,
478 // Create the PassManagerBuilder for LLVM. We configure it with
479 // reasonable defaults and prepare it to actually populate the pass
481 let builder = llvm::LLVMPassManagerBuilderCreate();
483 llvm::CodeGenLevelNone => {
484 // Don't add lifetime intrinsics at O0
485 llvm::LLVMRustAddAlwaysInlinePass(builder, false);
487 llvm::CodeGenLevelLess => {
488 llvm::LLVMRustAddAlwaysInlinePass(builder, true);
490 // numeric values copied from clang
491 llvm::CodeGenLevelDefault => {
492 llvm::LLVMPassManagerBuilderUseInlinerWithThreshold(builder,
495 llvm::CodeGenLevelAggressive => {
496 llvm::LLVMPassManagerBuilderUseInlinerWithThreshold(builder,
500 llvm::LLVMPassManagerBuilderSetOptLevel(builder, opt as c_uint);
501 llvm::LLVMRustAddBuilderLibraryInfo(builder, llmod, no_builtins);
503 // Use the builder to populate the function/module pass managers.
504 llvm::LLVMPassManagerBuilderPopulateFunctionPassManager(builder, fpm);
505 llvm::LLVMPassManagerBuilderPopulateModulePassManager(builder, mpm);
506 llvm::LLVMPassManagerBuilderDispose(builder);
512 * Name mangling and its relationship to metadata. This is complex. Read
515 * The semantic model of Rust linkage is, broadly, that "there's no global
516 * namespace" between crates. Our aim is to preserve the illusion of this
517 * model despite the fact that it's not *quite* possible to implement on
518 * modern linkers. We initially didn't use system linkers at all, but have
519 * been convinced of their utility.
521 * There are a few issues to handle:
523 * - Linkers operate on a flat namespace, so we have to flatten names.
524 * We do this using the C++ namespace-mangling technique. Foo::bar
527 * - Symbols with the same name but different types need to get different
528 * linkage-names. We do this by hashing a string-encoding of the type into
529 * a fixed-size (currently 16-byte hex) cryptographic hash function (CHF:
530 * we use SHA256) to "prevent collisions". This is not airtight but 16 hex
531 * digits on uniform probability means you're going to need 2**32 same-name
532 * symbols in the same process before you're even hitting birthday-paradox
533 * collision probability.
535 * - Symbols in different crates but with same names "within" the crate need
536 * to get different linkage-names.
538 * - The hash shown in the filename needs to be predictable and stable for
539 * build tooling integration. It also needs to be using a hash function
540 * which is easy to use from Python, make, etc.
542 * So here is what we do:
544 * - Consider the package id; every crate has one (specified with crate_id
545 * attribute). If a package id isn't provided explicitly, we infer a
546 * versionless one from the output name. The version will end up being 0.0
547 * in this case. CNAME and CVERS are taken from this package id. For
548 * example, github.com/mozilla/CNAME#CVERS.
550 * - Define CMH as SHA256(crateid).
552 * - Define CMH8 as the first 8 characters of CMH.
554 * - Compile our crate to lib CNAME-CMH8-CVERS.so
556 * - Define STH(sym) as SHA256(CMH, type_str(sym))
558 * - Suffix a mangled sym with ::STH@CVERS, so that it is unique in the
559 * name, non-name metadata, and type sense, and versioned in the way
560 * system linkers understand.
563 pub fn find_crate_name(sess: Option<&Session>,
564 attrs: &[ast::Attribute],
565 input: &Input) -> String {
566 use syntax::crateid::CrateId;
568 let validate = |s: String, span: Option<Span>| {
569 creader::validate_crate_name(sess, s.as_slice(), span);
573 // Look in attributes 100% of the time to make sure the attribute is marked
574 // as used. After doing this, however, we still prioritize a crate name from
575 // the command line over one found in the #[crate_name] attribute. If we
576 // find both we ensure that they're the same later on as well.
577 let attr_crate_name = attrs.iter().find(|at| at.check_name("crate_name"))
578 .and_then(|at| at.value_str().map(|s| (at, s)));
582 match sess.opts.crate_name {
584 match attr_crate_name {
585 Some((attr, ref name)) if s.as_slice() != name.get() => {
586 let msg = format!("--crate-name and #[crate_name] \
587 are required to match, but `{}` \
589 sess.span_err(attr.span, msg.as_slice());
593 return validate(s.clone(), None);
601 match attr_crate_name {
602 Some((attr, s)) => return validate(s.get().to_string(), Some(attr.span)),
605 let crate_id = attrs.iter().find(|at| at.check_name("crate_id"))
606 .and_then(|at| at.value_str().map(|s| (at, s)))
607 .and_then(|(at, s)| {
608 from_str::<CrateId>(s.get()).map(|id| (at, id))
611 Some((attr, id)) => {
614 sess.span_warn(attr.span, "the #[crate_id] attribute is \
616 #[crate_name] attribute");
620 return validate(id.name, Some(attr.span))
625 FileInput(ref path) => {
626 match path.filestem_str() {
627 Some(s) => return validate(s.to_string(), None),
634 "rust-out".to_string()
637 pub fn build_link_meta(sess: &Session, krate: &ast::Crate,
638 name: String) -> LinkMeta {
641 crate_hash: Svh::calculate(&sess.opts.cg.metadata, krate),
647 fn truncated_hash_result(symbol_hasher: &mut Sha256) -> String {
648 let output = symbol_hasher.result_bytes();
649 // 64 bits should be enough to avoid collisions.
650 output.slice_to(8).to_hex().to_string()
654 // This calculates STH for a symbol, as defined above
655 fn symbol_hash(tcx: &ty::ctxt,
656 symbol_hasher: &mut Sha256,
658 link_meta: &LinkMeta)
660 // NB: do *not* use abbrevs here as we want the symbol names
661 // to be independent of one another in the crate.
663 symbol_hasher.reset();
664 symbol_hasher.input_str(link_meta.crate_name.as_slice());
665 symbol_hasher.input_str("-");
666 symbol_hasher.input_str(link_meta.crate_hash.as_str());
667 for meta in tcx.sess.crate_metadata.borrow().iter() {
668 symbol_hasher.input_str(meta.as_slice());
670 symbol_hasher.input_str("-");
671 symbol_hasher.input_str(encoder::encoded_ty(tcx, t).as_slice());
672 // Prefix with 'h' so that it never blends into adjacent digits
673 let mut hash = String::from_str("h");
674 hash.push_str(truncated_hash_result(symbol_hasher).as_slice());
678 fn get_symbol_hash(ccx: &CrateContext, t: ty::t) -> String {
679 match ccx.type_hashcodes.borrow().find(&t) {
680 Some(h) => return h.to_string(),
684 let mut symbol_hasher = ccx.symbol_hasher.borrow_mut();
685 let hash = symbol_hash(ccx.tcx(), &mut *symbol_hasher, t, &ccx.link_meta);
686 ccx.type_hashcodes.borrow_mut().insert(t, hash.clone());
691 // Name sanitation. LLVM will happily accept identifiers with weird names, but
693 // gas accepts the following characters in symbols: a-z, A-Z, 0-9, ., _, $
694 pub fn sanitize(s: &str) -> String {
695 let mut result = String::new();
698 // Escape these with $ sequences
699 '@' => result.push_str("$SP$"),
700 '~' => result.push_str("$UP$"),
701 '*' => result.push_str("$RP$"),
702 '&' => result.push_str("$BP$"),
703 '<' => result.push_str("$LT$"),
704 '>' => result.push_str("$GT$"),
705 '(' => result.push_str("$LP$"),
706 ')' => result.push_str("$RP$"),
707 ',' => result.push_str("$C$"),
709 // '.' doesn't occur in types and functions, so reuse it
711 '-' | ':' => result.push_char('.'),
713 // These are legal symbols
717 | '_' | '.' | '$' => result.push_char(c),
720 let mut tstr = String::new();
721 char::escape_unicode(c, |c| tstr.push_char(c));
722 result.push_char('$');
723 result.push_str(tstr.as_slice().slice_from(1));
728 // Underscore-qualify anything that didn't start as an ident.
729 if result.len() > 0u &&
730 result.as_bytes()[0] != '_' as u8 &&
731 ! char::is_XID_start(result.as_bytes()[0] as char) {
732 return format!("_{}", result.as_slice());
738 pub fn mangle<PI: Iterator<PathElem>>(mut path: PI,
739 hash: Option<&str>) -> String {
740 // Follow C++ namespace-mangling style, see
741 // http://en.wikipedia.org/wiki/Name_mangling for more info.
743 // It turns out that on OSX you can actually have arbitrary symbols in
744 // function names (at least when given to LLVM), but this is not possible
745 // when using unix's linker. Perhaps one day when we just use a linker from LLVM
746 // we won't need to do this name mangling. The problem with name mangling is
747 // that it seriously limits the available characters. For example we can't
748 // have things like &T or ~[T] in symbol names when one would theoretically
749 // want them for things like impls of traits on that type.
751 // To be able to work on all platforms and get *some* reasonable output, we
752 // use C++ name-mangling.
754 let mut n = String::from_str("_ZN"); // _Z == Begin name-sequence, N == nested
756 fn push(n: &mut String, s: &str) {
757 let sani = sanitize(s);
758 n.push_str(format!("{}{}", sani.len(), sani).as_slice());
761 // First, connect each component with <len, name> pairs.
763 push(&mut n, token::get_name(e.name()).get().as_slice())
767 Some(s) => push(&mut n, s),
771 n.push_char('E'); // End name-sequence.
775 pub fn exported_name(path: PathElems, hash: &str) -> String {
776 mangle(path, Some(hash))
779 pub fn mangle_exported_name(ccx: &CrateContext, path: PathElems,
780 t: ty::t, id: ast::NodeId) -> String {
781 let mut hash = get_symbol_hash(ccx, t);
783 // Paths can be completely identical for different nodes,
784 // e.g. `fn foo() { { fn a() {} } { fn a() {} } }`, so we
785 // generate unique characters from the node id. For now
786 // hopefully 3 characters is enough to avoid collisions.
787 static EXTRA_CHARS: &'static str =
788 "abcdefghijklmnopqrstuvwxyz\
789 ABCDEFGHIJKLMNOPQRSTUVWXYZ\
792 let extra1 = id % EXTRA_CHARS.len();
793 let id = id / EXTRA_CHARS.len();
794 let extra2 = id % EXTRA_CHARS.len();
795 let id = id / EXTRA_CHARS.len();
796 let extra3 = id % EXTRA_CHARS.len();
797 hash.push_char(EXTRA_CHARS.as_bytes()[extra1] as char);
798 hash.push_char(EXTRA_CHARS.as_bytes()[extra2] as char);
799 hash.push_char(EXTRA_CHARS.as_bytes()[extra3] as char);
801 exported_name(path, hash.as_slice())
804 pub fn mangle_internal_name_by_type_and_seq(ccx: &CrateContext,
806 name: &str) -> String {
807 let s = ppaux::ty_to_string(ccx.tcx(), t);
808 let path = [PathName(token::intern(s.as_slice())),
810 let hash = get_symbol_hash(ccx, t);
811 mangle(ast_map::Values(path.iter()), Some(hash.as_slice()))
814 pub fn mangle_internal_name_by_path_and_seq(path: PathElems, flav: &str) -> String {
815 mangle(path.chain(Some(gensym_name(flav)).move_iter()), None)
818 pub fn get_cc_prog(sess: &Session) -> String {
819 match sess.opts.cg.linker {
820 Some(ref linker) => return linker.to_string(),
824 // In the future, FreeBSD will use clang as default compiler.
825 // It would be flexible to use cc (system's default C compiler)
826 // instead of hard-coded gcc.
827 // For win32, there is no cc command, so we add a condition to make it use gcc.
828 match sess.targ_cfg.os {
829 abi::OsWin32 => "gcc",
834 pub fn get_ar_prog(sess: &Session) -> String {
835 match sess.opts.cg.ar {
836 Some(ref ar) => (*ar).clone(),
837 None => "ar".to_string()
841 fn remove(sess: &Session, path: &Path) {
842 match fs::unlink(path) {
845 sess.err(format!("failed to remove {}: {}",
852 /// Perform the linkage portion of the compilation phase. This will generate all
853 /// of the requested outputs for this compilation session.
854 pub fn link_binary(sess: &Session,
855 trans: &CrateTranslation,
856 outputs: &OutputFilenames,
857 crate_name: &str) -> Vec<Path> {
858 let mut out_filenames = Vec::new();
859 for &crate_type in sess.crate_types.borrow().iter() {
860 if invalid_output_for_target(sess, crate_type) {
861 sess.bug(format!("invalid output type `{}` for target os `{}`",
862 crate_type, sess.targ_cfg.os).as_slice());
864 let out_file = link_binary_output(sess, trans, crate_type, outputs,
866 out_filenames.push(out_file);
869 // Remove the temporary object file and metadata if we aren't saving temps
870 if !sess.opts.cg.save_temps {
871 let obj_filename = outputs.temp_path(OutputTypeObject);
872 if !sess.opts.output_types.contains(&OutputTypeObject) {
873 remove(sess, &obj_filename);
875 remove(sess, &obj_filename.with_extension("metadata.o"));
882 /// Returns default crate type for target
884 /// Default crate type is used when crate type isn't provided neither
885 /// through cmd line arguments nor through crate attributes
887 /// It is CrateTypeExecutable for all platforms but iOS as there is no
888 /// way to run iOS binaries anyway without jailbreaking and
889 /// interaction with Rust code through static library is the only
891 pub fn default_output_for_target(sess: &Session) -> config::CrateType {
892 match sess.targ_cfg.os {
893 abi::OsiOS => config::CrateTypeStaticlib,
894 _ => config::CrateTypeExecutable
898 /// Checks if target supports crate_type as output
899 pub fn invalid_output_for_target(sess: &Session,
900 crate_type: config::CrateType) -> bool {
901 match (sess.targ_cfg.os, crate_type) {
902 (abi::OsiOS, config::CrateTypeDylib) => true,
907 fn is_writeable(p: &Path) -> bool {
910 Ok(m) => m.perm & io::UserWrite == io::UserWrite
914 pub fn filename_for_input(sess: &Session,
915 crate_type: config::CrateType,
917 out_filename: &Path) -> Path {
918 let libname = format!("{}{}", name, sess.opts.cg.extra_filename);
920 config::CrateTypeRlib => {
921 out_filename.with_filename(format!("lib{}.rlib", libname))
923 config::CrateTypeDylib => {
924 let (prefix, suffix) = match sess.targ_cfg.os {
925 abi::OsWin32 => (loader::WIN32_DLL_PREFIX, loader::WIN32_DLL_SUFFIX),
926 abi::OsMacos => (loader::MACOS_DLL_PREFIX, loader::MACOS_DLL_SUFFIX),
927 abi::OsLinux => (loader::LINUX_DLL_PREFIX, loader::LINUX_DLL_SUFFIX),
928 abi::OsAndroid => (loader::ANDROID_DLL_PREFIX, loader::ANDROID_DLL_SUFFIX),
929 abi::OsFreebsd => (loader::FREEBSD_DLL_PREFIX, loader::FREEBSD_DLL_SUFFIX),
930 abi::OsiOS => unreachable!(),
932 out_filename.with_filename(format!("{}{}{}",
937 config::CrateTypeStaticlib => {
938 out_filename.with_filename(format!("lib{}.a", libname))
940 config::CrateTypeExecutable => {
941 match sess.targ_cfg.os {
942 abi::OsWin32 => out_filename.with_extension("exe"),
947 abi::OsiOS => out_filename.clone(),
953 fn link_binary_output(sess: &Session,
954 trans: &CrateTranslation,
955 crate_type: config::CrateType,
956 outputs: &OutputFilenames,
957 crate_name: &str) -> Path {
958 let obj_filename = outputs.temp_path(OutputTypeObject);
959 let out_filename = match outputs.single_output_file {
960 Some(ref file) => file.clone(),
962 let out_filename = outputs.path(OutputTypeExe);
963 filename_for_input(sess, crate_type, crate_name, &out_filename)
967 // Make sure the output and obj_filename are both writeable.
968 // Mac, FreeBSD, and Windows system linkers check this already --
969 // however, the Linux linker will happily overwrite a read-only file.
970 // We should be consistent.
971 let obj_is_writeable = is_writeable(&obj_filename);
972 let out_is_writeable = is_writeable(&out_filename);
973 if !out_is_writeable {
974 sess.fatal(format!("output file {} is not writeable -- check its \
976 out_filename.display()).as_slice());
978 else if !obj_is_writeable {
979 sess.fatal(format!("object file {} is not writeable -- check its \
981 obj_filename.display()).as_slice());
985 config::CrateTypeRlib => {
986 link_rlib(sess, Some(trans), &obj_filename, &out_filename);
988 config::CrateTypeStaticlib => {
989 link_staticlib(sess, &obj_filename, &out_filename);
991 config::CrateTypeExecutable => {
992 link_natively(sess, trans, false, &obj_filename, &out_filename);
994 config::CrateTypeDylib => {
995 link_natively(sess, trans, true, &obj_filename, &out_filename);
1002 fn archive_search_paths(sess: &Session) -> Vec<Path> {
1003 let mut rustpath = filesearch::rust_path();
1004 rustpath.push(sess.target_filesearch().get_lib_path());
1005 // FIXME: Addl lib search paths are an unordered HashSet?
1006 // Shouldn't this search be done in some order?
1007 let addl_lib_paths: HashSet<Path> = sess.opts.addl_lib_search_paths.borrow().clone();
1008 let mut search: Vec<Path> = addl_lib_paths.move_iter().collect();
1009 search.push_all(rustpath.as_slice());
1015 // An rlib in its current incarnation is essentially a renamed .a file. The
1016 // rlib primarily contains the object file of the crate, but it also contains
1017 // all of the object files from native libraries. This is done by unzipping
1018 // native libraries and inserting all of the contents into this archive.
1019 fn link_rlib<'a>(sess: &'a Session,
1020 trans: Option<&CrateTranslation>, // None == no metadata/bytecode
1021 obj_filename: &Path,
1022 out_filename: &Path) -> Archive<'a> {
1023 let handler = &sess.diagnostic().handler;
1024 let config = ArchiveConfig {
1026 dst: out_filename.clone(),
1027 lib_search_paths: archive_search_paths(sess),
1028 os: sess.targ_cfg.os,
1029 maybe_ar_prog: sess.opts.cg.ar.clone()
1031 let mut a = Archive::create(config, obj_filename);
1033 for &(ref l, kind) in sess.cstore.get_used_libraries().borrow().iter() {
1035 cstore::NativeStatic => {
1036 a.add_native_library(l.as_slice()).unwrap();
1038 cstore::NativeFramework | cstore::NativeUnknown => {}
1042 // Note that it is important that we add all of our non-object "magical
1043 // files" *after* all of the object files in the archive. The reason for
1044 // this is as follows:
1046 // * When performing LTO, this archive will be modified to remove
1047 // obj_filename from above. The reason for this is described below.
1049 // * When the system linker looks at an archive, it will attempt to
1050 // determine the architecture of the archive in order to see whether its
1053 // The algorithm for this detection is: iterate over the files in the
1054 // archive. Skip magical SYMDEF names. Interpret the first file as an
1055 // object file. Read architecture from the object file.
1057 // * As one can probably see, if "metadata" and "foo.bc" were placed
1058 // before all of the objects, then the architecture of this archive would
1059 // not be correctly inferred once 'foo.o' is removed.
1061 // Basically, all this means is that this code should not move above the
1065 // Instead of putting the metadata in an object file section, rlibs
1066 // contain the metadata in a separate file. We use a temp directory
1067 // here so concurrent builds in the same directory don't try to use
1068 // the same filename for metadata (stomping over one another)
1069 let tmpdir = TempDir::new("rustc").expect("needs a temp dir");
1070 let metadata = tmpdir.path().join(METADATA_FILENAME);
1071 match fs::File::create(&metadata).write(trans.metadata
1075 sess.err(format!("failed to write {}: {}",
1078 sess.abort_if_errors();
1081 a.add_file(&metadata, false);
1082 remove(sess, &metadata);
1084 // For LTO purposes, the bytecode of this library is also inserted
1085 // into the archive.
1087 // Note that we make sure that the bytecode filename in the archive
1088 // is never exactly 16 bytes long by adding a 16 byte extension to
1089 // it. This is to work around a bug in LLDB that would cause it to
1090 // crash if the name of a file in an archive was exactly 16 bytes.
1091 let bc = obj_filename.with_extension("bc");
1092 let bc_deflated = obj_filename.with_extension("bytecode.deflate");
1093 match fs::File::open(&bc).read_to_end().and_then(|data| {
1094 fs::File::create(&bc_deflated)
1095 .write(match flate::deflate_bytes(data.as_slice()) {
1096 Some(compressed) => compressed,
1097 None => sess.fatal("failed to compress bytecode")
1102 sess.err(format!("failed to write compressed bytecode: \
1105 sess.abort_if_errors()
1108 a.add_file(&bc_deflated, false);
1109 remove(sess, &bc_deflated);
1110 if !sess.opts.cg.save_temps &&
1111 !sess.opts.output_types.contains(&OutputTypeBitcode) {
1115 // After adding all files to the archive, we need to update the
1116 // symbol table of the archive. This currently dies on OSX (see
1117 // #11162), and isn't necessary there anyway
1118 match sess.targ_cfg.os {
1119 abi::OsMacos | abi::OsiOS => {}
1120 _ => { a.update_symbols(); }
1129 // Create a static archive
1131 // This is essentially the same thing as an rlib, but it also involves adding
1132 // all of the upstream crates' objects into the archive. This will slurp in
1133 // all of the native libraries of upstream dependencies as well.
1135 // Additionally, there's no way for us to link dynamic libraries, so we warn
1136 // about all dynamic library dependencies that they're not linked in.
1138 // There's no need to include metadata in a static archive, so ensure to not
1139 // link in the metadata object file (and also don't prepare the archive with a
1141 fn link_staticlib(sess: &Session, obj_filename: &Path, out_filename: &Path) {
1142 let mut a = link_rlib(sess, None, obj_filename, out_filename);
1143 a.add_native_library("morestack").unwrap();
1144 a.add_native_library("compiler-rt").unwrap();
1146 let crates = sess.cstore.get_used_crates(cstore::RequireStatic);
1147 let mut all_native_libs = vec![];
1149 for &(cnum, ref path) in crates.iter() {
1150 let name = sess.cstore.get_crate_data(cnum).name.clone();
1151 let p = match *path {
1152 Some(ref p) => p.clone(), None => {
1153 sess.err(format!("could not find rlib for: `{}`",
1158 a.add_rlib(&p, name.as_slice(), sess.lto()).unwrap();
1160 let native_libs = csearch::get_native_libraries(&sess.cstore, cnum);
1161 all_native_libs.extend(native_libs.move_iter());
1164 if !all_native_libs.is_empty() {
1165 sess.warn("link against the following native artifacts when linking against \
1166 this static library");
1167 sess.note("the order and any duplication can be significant on some platforms, \
1168 and so may need to be preserved");
1171 for &(kind, ref lib) in all_native_libs.iter() {
1172 let name = match kind {
1173 cstore::NativeStatic => "static library",
1174 cstore::NativeUnknown => "library",
1175 cstore::NativeFramework => "framework",
1177 sess.note(format!("{}: {}", name, *lib).as_slice());
1181 // Create a dynamic library or executable
1183 // This will invoke the system linker/cc to create the resulting file. This
1184 // links to all upstream files as well.
1185 fn link_natively(sess: &Session, trans: &CrateTranslation, dylib: bool,
1186 obj_filename: &Path, out_filename: &Path) {
1187 let tmpdir = TempDir::new("rustc").expect("needs a temp dir");
1189 // The invocations of cc share some flags across platforms
1190 let pname = get_cc_prog(sess);
1191 let mut cmd = Command::new(pname.as_slice());
1193 cmd.args(sess.targ_cfg.target_strs.cc_args.as_slice());
1194 link_args(&mut cmd, sess, dylib, tmpdir.path(),
1195 trans, obj_filename, out_filename);
1197 if (sess.opts.debugging_opts & config::PRINT_LINK_ARGS) != 0 {
1198 println!("{}", &cmd);
1201 // May have not found libraries in the right formats.
1202 sess.abort_if_errors();
1204 // Invoke the system linker
1206 let prog = time(sess.time_passes(), "running linker", (), |()| cmd.output());
1209 if !prog.status.success() {
1210 sess.err(format!("linking with `{}` failed: {}",
1212 prog.status).as_slice());
1213 sess.note(format!("{}", &cmd).as_slice());
1214 let mut output = prog.error.clone();
1215 output.push_all(prog.output.as_slice());
1216 sess.note(str::from_utf8(output.as_slice()).unwrap());
1217 sess.abort_if_errors();
1221 sess.err(format!("could not exec the linker `{}`: {}",
1224 sess.abort_if_errors();
1229 // On OSX, debuggers need this utility to get run to do some munging of
1231 if (sess.targ_cfg.os == abi::OsMacos || sess.targ_cfg.os == abi::OsiOS)
1232 && (sess.opts.debuginfo != NoDebugInfo) {
1233 match Command::new("dsymutil").arg(out_filename).status() {
1236 sess.err(format!("failed to run dsymutil: {}", e).as_slice());
1237 sess.abort_if_errors();
1243 fn link_args(cmd: &mut Command,
1247 trans: &CrateTranslation,
1248 obj_filename: &Path,
1249 out_filename: &Path) {
1251 // The default library location, we need this to find the runtime.
1252 // The location of crates will be determined as needed.
1253 let lib_path = sess.target_filesearch().get_lib_path();
1254 cmd.arg("-L").arg(&lib_path);
1256 cmd.arg("-o").arg(out_filename).arg(obj_filename);
1258 // Stack growth requires statically linking a __morestack function. Note
1259 // that this is listed *before* all other libraries. Due to the usage of the
1260 // --as-needed flag below, the standard library may only be useful for its
1261 // rust_stack_exhausted function. In this case, we must ensure that the
1262 // libmorestack.a file appears *before* the standard library (so we put it
1263 // at the very front).
1265 // Most of the time this is sufficient, except for when LLVM gets super
1266 // clever. If, for example, we have a main function `fn main() {}`, LLVM
1267 // will optimize out calls to `__morestack` entirely because the function
1268 // doesn't need any stack at all!
1270 // To get around this snag, we specially tell the linker to always include
1271 // all contents of this library. This way we're guaranteed that the linker
1272 // will include the __morestack symbol 100% of the time, always resolving
1273 // references to it even if the object above didn't use it.
1274 match sess.targ_cfg.os {
1275 abi::OsMacos | abi::OsiOS => {
1276 let morestack = lib_path.join("libmorestack.a");
1278 let mut v = b"-Wl,-force_load,".to_vec();
1279 v.push_all(morestack.as_vec());
1280 cmd.arg(v.as_slice());
1283 cmd.args(["-Wl,--whole-archive", "-lmorestack",
1284 "-Wl,--no-whole-archive"]);
1288 // When linking a dynamic library, we put the metadata into a section of the
1289 // executable. This metadata is in a separate object file from the main
1290 // object file, so we link that in here.
1292 cmd.arg(obj_filename.with_extension("metadata.o"));
1295 // We want to prevent the compiler from accidentally leaking in any system
1296 // libraries, so we explicitly ask gcc to not link to any libraries by
1297 // default. Note that this does not happen for windows because windows pulls
1298 // in some large number of libraries and I couldn't quite figure out which
1299 // subset we wanted.
1301 // FIXME(#11937) we should invoke the system linker directly
1302 if sess.targ_cfg.os != abi::OsWin32 {
1303 cmd.arg("-nodefaultlibs");
1306 // If we're building a dylib, we don't use --gc-sections because LLVM has
1307 // already done the best it can do, and we also don't want to eliminate the
1308 // metadata. If we're building an executable, however, --gc-sections drops
1309 // the size of hello world from 1.8MB to 597K, a 67% reduction.
1310 if !dylib && sess.targ_cfg.os != abi::OsMacos && sess.targ_cfg.os != abi::OsiOS {
1311 cmd.arg("-Wl,--gc-sections");
1314 if sess.targ_cfg.os == abi::OsLinux {
1315 // GNU-style linkers will use this to omit linking to libraries which
1316 // don't actually fulfill any relocations, but only for libraries which
1317 // follow this flag. Thus, use it before specifying libraries to link to.
1318 cmd.arg("-Wl,--as-needed");
1320 // GNU-style linkers support optimization with -O. GNU ld doesn't need a
1321 // numeric argument, but other linkers do.
1322 if sess.opts.optimize == config::Default ||
1323 sess.opts.optimize == config::Aggressive {
1326 } else if sess.targ_cfg.os == abi::OsMacos || sess.targ_cfg.os == abi::OsiOS {
1327 // The dead_strip option to the linker specifies that functions and data
1328 // unreachable by the entry point will be removed. This is quite useful
1329 // with Rust's compilation model of compiling libraries at a time into
1330 // one object file. For example, this brings hello world from 1.7MB to
1333 // Note that this is done for both executables and dynamic libraries. We
1334 // won't get much benefit from dylibs because LLVM will have already
1335 // stripped away as much as it could. This has not been seen to impact
1336 // link times negatively.
1337 cmd.arg("-Wl,-dead_strip");
1340 if sess.targ_cfg.os == abi::OsWin32 {
1341 // Make sure that we link to the dynamic libgcc, otherwise cross-module
1342 // DWARF stack unwinding will not work.
1343 // This behavior may be overridden by --link-args "-static-libgcc"
1344 cmd.arg("-shared-libgcc");
1346 // And here, we see obscure linker flags #45. On windows, it has been
1347 // found to be necessary to have this flag to compile liblibc.
1349 // First a bit of background. On Windows, the file format is not ELF,
1350 // but COFF (at least according to LLVM). COFF doesn't officially allow
1351 // for section names over 8 characters, apparently. Our metadata
1352 // section, ".note.rustc", you'll note is over 8 characters.
1354 // On more recent versions of gcc on mingw, apparently the section name
1355 // is *not* truncated, but rather stored elsewhere in a separate lookup
1356 // table. On older versions of gcc, they apparently always truncated the
1357 // section names (at least in some cases). Truncating the section name
1358 // actually creates "invalid" objects [1] [2], but only for some
1359 // introspection tools, not in terms of whether it can be loaded.
1361 // Long story short, passing this flag forces the linker to *not*
1362 // truncate section names (so we can find the metadata section after
1363 // it's compiled). The real kicker is that rust compiled just fine on
1364 // windows for quite a long time *without* this flag, so I have no idea
1365 // why it suddenly started failing for liblibc. Regardless, we
1366 // definitely don't want section name truncation, so we're keeping this
1367 // flag for windows.
1369 // [1] - https://sourceware.org/bugzilla/show_bug.cgi?id=13130
1370 // [2] - https://code.google.com/p/go/issues/detail?id=2139
1371 cmd.arg("-Wl,--enable-long-section-names");
1374 if sess.targ_cfg.os == abi::OsAndroid {
1375 // Many of the symbols defined in compiler-rt are also defined in libgcc.
1376 // Android linker doesn't like that by default.
1377 cmd.arg("-Wl,--allow-multiple-definition");
1380 // Take careful note of the ordering of the arguments we pass to the linker
1381 // here. Linkers will assume that things on the left depend on things to the
1382 // right. Things on the right cannot depend on things on the left. This is
1383 // all formally implemented in terms of resolving symbols (libs on the right
1384 // resolve unknown symbols of libs on the left, but not vice versa).
1386 // For this reason, we have organized the arguments we pass to the linker as
1389 // 1. The local object that LLVM just generated
1390 // 2. Upstream rust libraries
1391 // 3. Local native libraries
1392 // 4. Upstream native libraries
1394 // This is generally fairly natural, but some may expect 2 and 3 to be
1395 // swapped. The reason that all native libraries are put last is that it's
1396 // not recommended for a native library to depend on a symbol from a rust
1397 // crate. If this is the case then a staticlib crate is recommended, solving
1400 // Additionally, it is occasionally the case that upstream rust libraries
1401 // depend on a local native library. In the case of libraries such as
1402 // lua/glfw/etc the name of the library isn't the same across all platforms,
1403 // so only the consumer crate of a library knows the actual name. This means
1404 // that downstream crates will provide the #[link] attribute which upstream
1405 // crates will depend on. Hence local native libraries are after out
1406 // upstream rust crates.
1408 // In theory this means that a symbol in an upstream native library will be
1409 // shadowed by a local native library when it wouldn't have been before, but
1410 // this kind of behavior is pretty platform specific and generally not
1411 // recommended anyway, so I don't think we're shooting ourself in the foot
1413 add_upstream_rust_crates(cmd, sess, dylib, tmpdir, trans);
1414 add_local_native_libraries(cmd, sess);
1415 add_upstream_native_libraries(cmd, sess);
1417 // # Telling the linker what we're doing
1420 // On mac we need to tell the linker to let this library be rpathed
1421 if sess.targ_cfg.os == abi::OsMacos {
1422 cmd.args(["-dynamiclib", "-Wl,-dylib"]);
1424 if sess.opts.cg.rpath {
1425 let mut v = Vec::from_slice("-Wl,-install_name,@rpath/".as_bytes());
1426 v.push_all(out_filename.filename().unwrap());
1427 cmd.arg(v.as_slice());
1434 if sess.targ_cfg.os == abi::OsFreebsd {
1435 cmd.args(["-L/usr/local/lib",
1436 "-L/usr/local/lib/gcc46",
1437 "-L/usr/local/lib/gcc44"]);
1440 // FIXME (#2397): At some point we want to rpath our guesses as to
1441 // where extern libraries might live, based on the
1442 // addl_lib_search_paths
1443 if sess.opts.cg.rpath {
1444 let sysroot = sess.sysroot();
1445 let target_triple = sess.opts.target_triple.as_slice();
1446 let get_install_prefix_lib_path = || {
1447 let install_prefix = option_env!("CFG_PREFIX").expect("CFG_PREFIX");
1448 let tlib = filesearch::relative_target_lib_path(sysroot, target_triple);
1449 let mut path = Path::new(install_prefix);
1454 let rpath_config = RPathConfig {
1455 os: sess.targ_cfg.os,
1456 used_crates: sess.cstore.get_used_crates(cstore::RequireDynamic),
1457 out_filename: out_filename.clone(),
1458 get_install_prefix_lib_path: get_install_prefix_lib_path,
1459 realpath: ::util::fs::realpath
1461 cmd.args(rpath::get_rpath_flags(rpath_config).as_slice());
1464 // compiler-rt contains implementations of low-level LLVM helpers. This is
1465 // used to resolve symbols from the object file we just created, as well as
1466 // any system static libraries that may be expecting gcc instead. Most
1467 // symbols in libgcc also appear in compiler-rt.
1469 // This is the end of the command line, so this library is used to resolve
1470 // *all* undefined symbols in all other libraries, and this is intentional.
1471 cmd.arg("-lcompiler-rt");
1473 // Finally add all the linker arguments provided on the command line along
1474 // with any #[link_args] attributes found inside the crate
1475 cmd.args(sess.opts.cg.link_args.as_slice());
1476 for arg in sess.cstore.get_used_link_args().borrow().iter() {
1477 cmd.arg(arg.as_slice());
1481 // # Native library linking
1483 // User-supplied library search paths (-L on the command line). These are
1484 // the same paths used to find Rust crates, so some of them may have been
1485 // added already by the previous crate linking code. This only allows them
1486 // to be found at compile time so it is still entirely up to outside
1487 // forces to make sure that library can be found at runtime.
1489 // Also note that the native libraries linked here are only the ones located
1490 // in the current crate. Upstream crates with native library dependencies
1491 // may have their native library pulled in above.
1492 fn add_local_native_libraries(cmd: &mut Command, sess: &Session) {
1493 for path in sess.opts.addl_lib_search_paths.borrow().iter() {
1494 cmd.arg("-L").arg(path);
1497 let rustpath = filesearch::rust_path();
1498 for path in rustpath.iter() {
1499 cmd.arg("-L").arg(path);
1502 // Some platforms take hints about whether a library is static or dynamic.
1503 // For those that support this, we ensure we pass the option if the library
1504 // was flagged "static" (most defaults are dynamic) to ensure that if
1505 // libfoo.a and libfoo.so both exist that the right one is chosen.
1506 let takes_hints = sess.targ_cfg.os != abi::OsMacos && sess.targ_cfg.os != abi::OsiOS;
1508 for &(ref l, kind) in sess.cstore.get_used_libraries().borrow().iter() {
1510 cstore::NativeUnknown | cstore::NativeStatic => {
1512 if kind == cstore::NativeStatic {
1513 cmd.arg("-Wl,-Bstatic");
1515 cmd.arg("-Wl,-Bdynamic");
1518 cmd.arg(format!("-l{}", *l));
1520 cstore::NativeFramework => {
1521 cmd.arg("-framework");
1522 cmd.arg(l.as_slice());
1527 cmd.arg("-Wl,-Bdynamic");
1531 // # Rust Crate linking
1533 // Rust crates are not considered at all when creating an rlib output. All
1534 // dependencies will be linked when producing the final output (instead of
1535 // the intermediate rlib version)
1536 fn add_upstream_rust_crates(cmd: &mut Command, sess: &Session,
1537 dylib: bool, tmpdir: &Path,
1538 trans: &CrateTranslation) {
1539 // All of the heavy lifting has previously been accomplished by the
1540 // dependency_format module of the compiler. This is just crawling the
1541 // output of that module, adding crates as necessary.
1543 // Linking to a rlib involves just passing it to the linker (the linker
1544 // will slurp up the object files inside), and linking to a dynamic library
1545 // involves just passing the right -l flag.
1547 let data = if dylib {
1548 trans.crate_formats.get(&config::CrateTypeDylib)
1550 trans.crate_formats.get(&config::CrateTypeExecutable)
1553 // Invoke get_used_crates to ensure that we get a topological sorting of
1555 let deps = sess.cstore.get_used_crates(cstore::RequireDynamic);
1557 for &(cnum, _) in deps.iter() {
1558 // We may not pass all crates through to the linker. Some crates may
1559 // appear statically in an existing dylib, meaning we'll pick up all the
1560 // symbols from the dylib.
1561 let kind = match *data.get(cnum as uint - 1) {
1565 let src = sess.cstore.get_used_crate_source(cnum).unwrap();
1567 cstore::RequireDynamic => {
1568 add_dynamic_crate(cmd, sess, src.dylib.unwrap())
1570 cstore::RequireStatic => {
1571 add_static_crate(cmd, sess, tmpdir, src.rlib.unwrap())
1577 // Converts a library file-stem into a cc -l argument
1578 fn unlib<'a>(config: &config::Config, stem: &'a [u8]) -> &'a [u8] {
1579 if stem.starts_with("lib".as_bytes()) && config.os != abi::OsWin32 {
1586 // Adds the static "rlib" versions of all crates to the command line.
1587 fn add_static_crate(cmd: &mut Command, sess: &Session, tmpdir: &Path,
1589 // When performing LTO on an executable output, all of the
1590 // bytecode from the upstream libraries has already been
1591 // included in our object file output. We need to modify all of
1592 // the upstream archives to remove their corresponding object
1593 // file to make sure we don't pull the same code in twice.
1595 // We must continue to link to the upstream archives to be sure
1596 // to pull in native static dependencies. As the final caveat,
1597 // on linux it is apparently illegal to link to a blank archive,
1598 // so if an archive no longer has any object files in it after
1599 // we remove `lib.o`, then don't link against it at all.
1601 // If we're not doing LTO, then our job is simply to just link
1602 // against the archive.
1604 let name = cratepath.filename_str().unwrap();
1605 let name = name.slice(3, name.len() - 5); // chop off lib/.rlib
1606 time(sess.time_passes(),
1607 format!("altering {}.rlib", name).as_slice(),
1609 let dst = tmpdir.join(cratepath.filename().unwrap());
1610 match fs::copy(&cratepath, &dst) {
1613 sess.err(format!("failed to copy {} to {}: {}",
1614 cratepath.display(),
1617 sess.abort_if_errors();
1620 let handler = &sess.diagnostic().handler;
1621 let config = ArchiveConfig {
1624 lib_search_paths: archive_search_paths(sess),
1625 os: sess.targ_cfg.os,
1626 maybe_ar_prog: sess.opts.cg.ar.clone()
1628 let mut archive = Archive::open(config);
1629 archive.remove_file(format!("{}.o", name).as_slice());
1630 let files = archive.files();
1631 if files.iter().any(|s| s.as_slice().ends_with(".o")) {
1640 // Same thing as above, but for dynamic crates instead of static crates.
1641 fn add_dynamic_crate(cmd: &mut Command, sess: &Session, cratepath: Path) {
1642 // If we're performing LTO, then it should have been previously required
1643 // that all upstream rust dependencies were available in an rlib format.
1644 assert!(!sess.lto());
1646 // Just need to tell the linker about where the library lives and
1648 let dir = cratepath.dirname();
1649 if !dir.is_empty() { cmd.arg("-L").arg(dir); }
1651 let mut v = Vec::from_slice("-l".as_bytes());
1652 v.push_all(unlib(&sess.targ_cfg, cratepath.filestem().unwrap()));
1653 cmd.arg(v.as_slice());
1657 // Link in all of our upstream crates' native dependencies. Remember that
1658 // all of these upstream native dependencies are all non-static
1659 // dependencies. We've got two cases then:
1661 // 1. The upstream crate is an rlib. In this case we *must* link in the
1662 // native dependency because the rlib is just an archive.
1664 // 2. The upstream crate is a dylib. In order to use the dylib, we have to
1665 // have the dependency present on the system somewhere. Thus, we don't
1666 // gain a whole lot from not linking in the dynamic dependency to this
1669 // The use case for this is a little subtle. In theory the native
1670 // dependencies of a crate are purely an implementation detail of the crate
1671 // itself, but the problem arises with generic and inlined functions. If a
1672 // generic function calls a native function, then the generic function must
1673 // be instantiated in the target crate, meaning that the native symbol must
1674 // also be resolved in the target crate.
1675 fn add_upstream_native_libraries(cmd: &mut Command, sess: &Session) {
1676 // Be sure to use a topological sorting of crates because there may be
1677 // interdependencies between native libraries. When passing -nodefaultlibs,
1678 // for example, almost all native libraries depend on libc, so we have to
1679 // make sure that's all the way at the right (liblibc is near the base of
1680 // the dependency chain).
1682 // This passes RequireStatic, but the actual requirement doesn't matter,
1683 // we're just getting an ordering of crate numbers, we're not worried about
1685 let crates = sess.cstore.get_used_crates(cstore::RequireStatic);
1686 for (cnum, _) in crates.move_iter() {
1687 let libs = csearch::get_native_libraries(&sess.cstore, cnum);
1688 for &(kind, ref lib) in libs.iter() {
1690 cstore::NativeUnknown => {
1691 cmd.arg(format!("-l{}", *lib));
1693 cstore::NativeFramework => {
1694 cmd.arg("-framework");
1695 cmd.arg(lib.as_slice());
1697 cstore::NativeStatic => {
1698 sess.bug("statics shouldn't be propagated");