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 back::archive::{Archive, METADATA_FILENAME};
14 use driver::driver::{CrateTranslation, OutputFilenames, Input, FileInput};
15 use driver::config::NoDebugInfo;
16 use driver::session::Session;
19 use lib::llvm::ModuleRef;
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::io::{fs, TempDir, Command};
36 use std::string::String;
38 use serialize::hex::ToHex;
41 use syntax::ast_map::{PathElem, PathElems, PathName};
43 use syntax::attr::AttrMetaMethods;
44 use syntax::codemap::Span;
45 use syntax::parse::token;
47 #[deriving(Clone, PartialEq, PartialOrd, Ord, Eq)]
51 OutputTypeLlvmAssembly,
56 pub fn llvm_err(sess: &Session, msg: String) -> ! {
58 let cstr = llvm::LLVMRustGetLastError();
59 if cstr == ptr::null() {
60 sess.fatal(msg.as_slice());
62 let err = CString::new(cstr, true);
63 let err = str::from_utf8_lossy(err.as_bytes());
64 sess.fatal(format!("{}: {}",
66 err.as_slice()).as_slice());
71 pub fn write_output_file(
73 target: lib::llvm::TargetMachineRef,
74 pm: lib::llvm::PassManagerRef,
77 file_type: lib::llvm::FileType) {
79 output.with_c_str(|output| {
80 let result = llvm::LLVMRustWriteOutputFile(
81 target, pm, m, output, file_type);
83 llvm_err(sess, "could not write output".to_string());
92 use back::link::{write_output_file, OutputType};
93 use back::link::{OutputTypeAssembly, OutputTypeBitcode};
94 use back::link::{OutputTypeExe, OutputTypeLlvmAssembly};
95 use back::link::{OutputTypeObject};
96 use driver::driver::{CrateTranslation, OutputFilenames};
97 use driver::config::NoDebugInfo;
98 use driver::session::Session;
101 use lib::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 => lib::llvm::CodeGenLevelNone,
156 config::Less => lib::llvm::CodeGenLevelLess,
157 config::Default => lib::llvm::CodeGenLevelDefault,
158 config::Aggressive => lib::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" => lib::llvm::RelocPIC,
176 "static" => lib::llvm::RelocStatic,
177 "default" => lib::llvm::RelocDefault,
178 "dynamic-no-pic" => lib::llvm::RelocDynamicNoPic,
180 sess.err(format!("{} is not a valid relocation mode",
183 .relocation_model).as_slice());
184 sess.abort_if_errors();
189 let tm = sess.targ_cfg
194 sess.opts.cg.target_cpu.as_slice().with_c_str(|cpu| {
195 target_feature(sess).with_c_str(|features| {
196 llvm::LLVMRustCreateTargetMachine(
198 lib::llvm::CodeModelDefault,
201 true /* EnableSegstk */,
211 // Create the two optimizing pass managers. These mirror what clang
212 // does, and are by populated by LLVM's default PassManagerBuilder.
213 // Each manager has a different set of passes, but they also share
214 // some common passes.
215 let fpm = llvm::LLVMCreateFunctionPassManagerForModule(llmod);
216 let mpm = llvm::LLVMCreatePassManager();
218 // If we're verifying or linting, add them to the function pass
220 let addpass = |pass: &str| {
221 pass.as_slice().with_c_str(|s| llvm::LLVMRustAddPass(fpm, s))
223 if !sess.no_verify() { assert!(addpass("verify")); }
225 if !sess.opts.cg.no_prepopulate_passes {
226 llvm::LLVMRustAddAnalysisPasses(tm, fpm, llmod);
227 llvm::LLVMRustAddAnalysisPasses(tm, mpm, llmod);
228 populate_llvm_passes(fpm, mpm, llmod, opt_level,
232 for pass in sess.opts.cg.passes.iter() {
233 pass.as_slice().with_c_str(|s| {
234 if !llvm::LLVMRustAddPass(mpm, s) {
235 sess.warn(format!("unknown pass {}, ignoring",
241 // Finally, run the actual optimization passes
242 time(sess.time_passes(), "llvm function passes", (), |()|
243 llvm::LLVMRustRunFunctionPassManager(fpm, llmod));
244 time(sess.time_passes(), "llvm module passes", (), |()|
245 llvm::LLVMRunPassManager(mpm, llmod));
247 // Deallocate managers that we're now done with
248 llvm::LLVMDisposePassManager(fpm);
249 llvm::LLVMDisposePassManager(mpm);
251 // Emit the bytecode if we're either saving our temporaries or
252 // emitting an rlib. Whenever an rlib is created, the bytecode is
253 // inserted into the archive in order to allow LTO against it.
254 if sess.opts.cg.save_temps ||
255 (sess.crate_types.borrow().contains(&config::CrateTypeRlib) &&
256 sess.opts.output_types.contains(&OutputTypeExe)) {
257 output.temp_path(OutputTypeBitcode).with_c_str(|buf| {
258 llvm::LLVMWriteBitcodeToFile(llmod, buf);
263 time(sess.time_passes(), "all lto passes", (), |()|
264 lto::run(sess, llmod, tm, trans.reachable.as_slice()));
266 if sess.opts.cg.save_temps {
267 output.with_extension("lto.bc").with_c_str(|buf| {
268 llvm::LLVMWriteBitcodeToFile(llmod, buf);
273 // A codegen-specific pass manager is used to generate object
274 // files for an LLVM module.
276 // Apparently each of these pass managers is a one-shot kind of
277 // thing, so we create a new one for each type of output. The
278 // pass manager passed to the closure should be ensured to not
279 // escape the closure itself, and the manager should only be
281 fn with_codegen(tm: TargetMachineRef, llmod: ModuleRef,
282 no_builtins: bool, f: |PassManagerRef|) {
284 let cpm = llvm::LLVMCreatePassManager();
285 llvm::LLVMRustAddAnalysisPasses(tm, cpm, llmod);
286 llvm::LLVMRustAddLibraryInfo(cpm, llmod, no_builtins);
288 llvm::LLVMDisposePassManager(cpm);
292 let mut object_file = None;
293 let mut needs_metadata = false;
294 for output_type in output_types.iter() {
295 let path = output.path(*output_type);
297 OutputTypeBitcode => {
298 path.with_c_str(|buf| {
299 llvm::LLVMWriteBitcodeToFile(llmod, buf);
302 OutputTypeLlvmAssembly => {
303 path.with_c_str(|output| {
304 with_codegen(tm, llmod, trans.no_builtins, |cpm| {
305 llvm::LLVMRustPrintModule(cpm, llmod, output);
309 OutputTypeAssembly => {
310 // If we're not using the LLVM assembler, this function
311 // could be invoked specially with output_type_assembly,
312 // so in this case we still want the metadata object
314 let ty = OutputTypeAssembly;
315 let path = if sess.opts.output_types.contains(&ty) {
318 needs_metadata = true;
319 output.temp_path(OutputTypeAssembly)
321 with_codegen(tm, llmod, trans.no_builtins, |cpm| {
322 write_output_file(sess, tm, cpm, llmod, &path,
323 lib::llvm::AssemblyFile);
326 OutputTypeObject => {
327 object_file = Some(path);
330 object_file = Some(output.temp_path(OutputTypeObject));
331 needs_metadata = true;
336 time(sess.time_passes(), "codegen passes", (), |()| {
339 with_codegen(tm, llmod, trans.no_builtins, |cpm| {
340 write_output_file(sess, tm, cpm, llmod, path,
341 lib::llvm::ObjectFile);
347 with_codegen(tm, trans.metadata_module,
348 trans.no_builtins, |cpm| {
349 let out = output.temp_path(OutputTypeObject)
350 .with_extension("metadata.o");
351 write_output_file(sess, tm, cpm,
352 trans.metadata_module, &out,
353 lib::llvm::ObjectFile);
358 llvm::LLVMRustDisposeTargetMachine(tm);
359 llvm::LLVMDisposeModule(trans.metadata_module);
360 llvm::LLVMDisposeModule(llmod);
361 llvm::LLVMContextDispose(llcx);
362 if sess.time_llvm_passes() { llvm::LLVMRustPrintPassTimings(); }
366 pub fn run_assembler(sess: &Session, outputs: &OutputFilenames) {
367 let pname = super::get_cc_prog(sess);
368 let mut cmd = Command::new(pname.as_slice());
370 cmd.arg("-c").arg("-o").arg(outputs.path(OutputTypeObject))
371 .arg(outputs.temp_path(OutputTypeAssembly));
376 if !prog.status.success() {
377 sess.err(format!("linking with `{}` failed: {}",
379 prog.status).as_slice());
380 sess.note(format!("{}", &cmd).as_slice());
381 let mut note = prog.error.clone();
382 note.push_all(prog.output.as_slice());
383 sess.note(str::from_utf8(note.as_slice()).unwrap()
385 sess.abort_if_errors();
389 sess.err(format!("could not exec the linker `{}`: {}",
392 sess.abort_if_errors();
397 unsafe fn configure_llvm(sess: &Session) {
398 use std::sync::{Once, ONCE_INIT};
399 static mut INIT: Once = ONCE_INIT;
401 // Copy what clang does by turning on loop vectorization at O2 and
402 // slp vectorization at O3
403 let vectorize_loop = !sess.opts.cg.no_vectorize_loops &&
404 (sess.opts.optimize == config::Default ||
405 sess.opts.optimize == config::Aggressive);
406 let vectorize_slp = !sess.opts.cg.no_vectorize_slp &&
407 sess.opts.optimize == config::Aggressive;
409 let mut llvm_c_strs = Vec::new();
410 let mut llvm_args = Vec::new();
412 let add = |arg: &str| {
413 let s = arg.to_c_str();
414 llvm_args.push(s.as_ptr());
417 add("rustc"); // fake program name
418 if vectorize_loop { add("-vectorize-loops"); }
419 if vectorize_slp { add("-vectorize-slp"); }
420 if sess.time_llvm_passes() { add("-time-passes"); }
421 if sess.print_llvm_passes() { add("-debug-pass=Structure"); }
423 for arg in sess.opts.cg.llvm_args.iter() {
424 add((*arg).as_slice());
429 llvm::LLVMInitializePasses();
431 // Only initialize the platforms supported by Rust here, because
432 // using --llvm-root will have multiple platforms that rustllvm
433 // doesn't actually link to and it's pointless to put target info
434 // into the registry that Rust cannot generate machine code for.
435 llvm::LLVMInitializeX86TargetInfo();
436 llvm::LLVMInitializeX86Target();
437 llvm::LLVMInitializeX86TargetMC();
438 llvm::LLVMInitializeX86AsmPrinter();
439 llvm::LLVMInitializeX86AsmParser();
441 llvm::LLVMInitializeARMTargetInfo();
442 llvm::LLVMInitializeARMTarget();
443 llvm::LLVMInitializeARMTargetMC();
444 llvm::LLVMInitializeARMAsmPrinter();
445 llvm::LLVMInitializeARMAsmParser();
447 llvm::LLVMInitializeMipsTargetInfo();
448 llvm::LLVMInitializeMipsTarget();
449 llvm::LLVMInitializeMipsTargetMC();
450 llvm::LLVMInitializeMipsAsmPrinter();
451 llvm::LLVMInitializeMipsAsmParser();
453 llvm::LLVMRustSetLLVMOptions(llvm_args.len() as c_int,
458 unsafe fn populate_llvm_passes(fpm: lib::llvm::PassManagerRef,
459 mpm: lib::llvm::PassManagerRef,
461 opt: lib::llvm::CodeGenOptLevel,
463 // Create the PassManagerBuilder for LLVM. We configure it with
464 // reasonable defaults and prepare it to actually populate the pass
466 let builder = llvm::LLVMPassManagerBuilderCreate();
468 lib::llvm::CodeGenLevelNone => {
469 // Don't add lifetime intrinsics at O0
470 llvm::LLVMRustAddAlwaysInlinePass(builder, false);
472 lib::llvm::CodeGenLevelLess => {
473 llvm::LLVMRustAddAlwaysInlinePass(builder, true);
475 // numeric values copied from clang
476 lib::llvm::CodeGenLevelDefault => {
477 llvm::LLVMPassManagerBuilderUseInlinerWithThreshold(builder,
480 lib::llvm::CodeGenLevelAggressive => {
481 llvm::LLVMPassManagerBuilderUseInlinerWithThreshold(builder,
485 llvm::LLVMPassManagerBuilderSetOptLevel(builder, opt as c_uint);
486 llvm::LLVMRustAddBuilderLibraryInfo(builder, llmod, no_builtins);
488 // Use the builder to populate the function/module pass managers.
489 llvm::LLVMPassManagerBuilderPopulateFunctionPassManager(builder, fpm);
490 llvm::LLVMPassManagerBuilderPopulateModulePassManager(builder, mpm);
491 llvm::LLVMPassManagerBuilderDispose(builder);
497 * Name mangling and its relationship to metadata. This is complex. Read
500 * The semantic model of Rust linkage is, broadly, that "there's no global
501 * namespace" between crates. Our aim is to preserve the illusion of this
502 * model despite the fact that it's not *quite* possible to implement on
503 * modern linkers. We initially didn't use system linkers at all, but have
504 * been convinced of their utility.
506 * There are a few issues to handle:
508 * - Linkers operate on a flat namespace, so we have to flatten names.
509 * We do this using the C++ namespace-mangling technique. Foo::bar
512 * - Symbols with the same name but different types need to get different
513 * linkage-names. We do this by hashing a string-encoding of the type into
514 * a fixed-size (currently 16-byte hex) cryptographic hash function (CHF:
515 * we use SHA256) to "prevent collisions". This is not airtight but 16 hex
516 * digits on uniform probability means you're going to need 2**32 same-name
517 * symbols in the same process before you're even hitting birthday-paradox
518 * collision probability.
520 * - Symbols in different crates but with same names "within" the crate need
521 * to get different linkage-names.
523 * - The hash shown in the filename needs to be predictable and stable for
524 * build tooling integration. It also needs to be using a hash function
525 * which is easy to use from Python, make, etc.
527 * So here is what we do:
529 * - Consider the package id; every crate has one (specified with crate_id
530 * attribute). If a package id isn't provided explicitly, we infer a
531 * versionless one from the output name. The version will end up being 0.0
532 * in this case. CNAME and CVERS are taken from this package id. For
533 * example, github.com/mozilla/CNAME#CVERS.
535 * - Define CMH as SHA256(crateid).
537 * - Define CMH8 as the first 8 characters of CMH.
539 * - Compile our crate to lib CNAME-CMH8-CVERS.so
541 * - Define STH(sym) as SHA256(CMH, type_str(sym))
543 * - Suffix a mangled sym with ::STH@CVERS, so that it is unique in the
544 * name, non-name metadata, and type sense, and versioned in the way
545 * system linkers understand.
548 pub fn find_crate_name(sess: Option<&Session>,
549 attrs: &[ast::Attribute],
550 input: &Input) -> String {
551 use syntax::crateid::CrateId;
553 let validate = |s: String, span: Option<Span>| {
554 creader::validate_crate_name(sess, s.as_slice(), span);
558 // Look in attributes 100% of the time to make sure the attribute is marked
559 // as used. After doing this, however, favor crate names from the command
561 let attr_crate_name = attrs.iter().find(|at| at.check_name("crate_name"))
562 .and_then(|at| at.value_str().map(|s| (at, s)));
566 match sess.opts.crate_name {
567 Some(ref s) => return validate(s.clone(), None),
574 match attr_crate_name {
575 Some((attr, s)) => return validate(s.get().to_string(), Some(attr.span)),
578 let crate_id = attrs.iter().find(|at| at.check_name("crate_id"))
579 .and_then(|at| at.value_str().map(|s| (at, s)))
580 .and_then(|(at, s)| {
581 from_str::<CrateId>(s.get()).map(|id| (at, id))
584 Some((attr, id)) => {
587 sess.span_warn(attr.span, "the #[crate_id] attribute is \
589 #[crate_name] attribute");
593 return validate(id.name, Some(attr.span))
598 FileInput(ref path) => {
599 match path.filestem_str() {
600 Some(s) => return validate(s.to_string(), None),
607 "rust-out".to_string()
610 pub fn build_link_meta(sess: &Session, krate: &ast::Crate,
611 name: String) -> LinkMeta {
614 crate_hash: Svh::calculate(sess, krate),
620 fn truncated_hash_result(symbol_hasher: &mut Sha256) -> String {
621 let output = symbol_hasher.result_bytes();
622 // 64 bits should be enough to avoid collisions.
623 output.slice_to(8).to_hex().to_string()
627 // This calculates STH for a symbol, as defined above
628 fn symbol_hash(tcx: &ty::ctxt,
629 symbol_hasher: &mut Sha256,
631 link_meta: &LinkMeta)
633 // NB: do *not* use abbrevs here as we want the symbol names
634 // to be independent of one another in the crate.
636 symbol_hasher.reset();
637 symbol_hasher.input_str(link_meta.crate_name.as_slice());
638 symbol_hasher.input_str("-");
639 symbol_hasher.input_str(link_meta.crate_hash.as_str());
640 for meta in tcx.sess.crate_metadata.borrow().iter() {
641 symbol_hasher.input_str(meta.as_slice());
643 symbol_hasher.input_str("-");
644 symbol_hasher.input_str(encoder::encoded_ty(tcx, t).as_slice());
645 // Prefix with 'h' so that it never blends into adjacent digits
646 let mut hash = String::from_str("h");
647 hash.push_str(truncated_hash_result(symbol_hasher).as_slice());
651 fn get_symbol_hash(ccx: &CrateContext, t: ty::t) -> String {
652 match ccx.type_hashcodes.borrow().find(&t) {
653 Some(h) => return h.to_string(),
657 let mut symbol_hasher = ccx.symbol_hasher.borrow_mut();
658 let hash = symbol_hash(ccx.tcx(), &mut *symbol_hasher, t, &ccx.link_meta);
659 ccx.type_hashcodes.borrow_mut().insert(t, hash.clone());
664 // Name sanitation. LLVM will happily accept identifiers with weird names, but
666 // gas accepts the following characters in symbols: a-z, A-Z, 0-9, ., _, $
667 pub fn sanitize(s: &str) -> String {
668 let mut result = String::new();
671 // Escape these with $ sequences
672 '@' => result.push_str("$SP$"),
673 '~' => result.push_str("$UP$"),
674 '*' => result.push_str("$RP$"),
675 '&' => result.push_str("$BP$"),
676 '<' => result.push_str("$LT$"),
677 '>' => result.push_str("$GT$"),
678 '(' => result.push_str("$LP$"),
679 ')' => result.push_str("$RP$"),
680 ',' => result.push_str("$C$"),
682 // '.' doesn't occur in types and functions, so reuse it
684 '-' | ':' => result.push_char('.'),
686 // These are legal symbols
690 | '_' | '.' | '$' => result.push_char(c),
693 let mut tstr = String::new();
694 char::escape_unicode(c, |c| tstr.push_char(c));
695 result.push_char('$');
696 result.push_str(tstr.as_slice().slice_from(1));
701 // Underscore-qualify anything that didn't start as an ident.
702 if result.len() > 0u &&
703 result.as_bytes()[0] != '_' as u8 &&
704 ! char::is_XID_start(result.as_bytes()[0] as char) {
705 return format!("_{}", result.as_slice());
711 pub fn mangle<PI: Iterator<PathElem>>(mut path: PI,
712 hash: Option<&str>) -> String {
713 // Follow C++ namespace-mangling style, see
714 // http://en.wikipedia.org/wiki/Name_mangling for more info.
716 // It turns out that on OSX you can actually have arbitrary symbols in
717 // function names (at least when given to LLVM), but this is not possible
718 // when using unix's linker. Perhaps one day when we just use a linker from LLVM
719 // we won't need to do this name mangling. The problem with name mangling is
720 // that it seriously limits the available characters. For example we can't
721 // have things like &T or ~[T] in symbol names when one would theoretically
722 // want them for things like impls of traits on that type.
724 // To be able to work on all platforms and get *some* reasonable output, we
725 // use C++ name-mangling.
727 let mut n = String::from_str("_ZN"); // _Z == Begin name-sequence, N == nested
729 fn push(n: &mut String, s: &str) {
730 let sani = sanitize(s);
731 n.push_str(format!("{}{}", sani.len(), sani).as_slice());
734 // First, connect each component with <len, name> pairs.
736 push(&mut n, token::get_name(e.name()).get().as_slice())
740 Some(s) => push(&mut n, s),
744 n.push_char('E'); // End name-sequence.
748 pub fn exported_name(path: PathElems, hash: &str) -> String {
749 mangle(path, Some(hash))
752 pub fn mangle_exported_name(ccx: &CrateContext, path: PathElems,
753 t: ty::t, id: ast::NodeId) -> String {
754 let mut hash = get_symbol_hash(ccx, t);
756 // Paths can be completely identical for different nodes,
757 // e.g. `fn foo() { { fn a() {} } { fn a() {} } }`, so we
758 // generate unique characters from the node id. For now
759 // hopefully 3 characters is enough to avoid collisions.
760 static EXTRA_CHARS: &'static str =
761 "abcdefghijklmnopqrstuvwxyz\
762 ABCDEFGHIJKLMNOPQRSTUVWXYZ\
765 let extra1 = id % EXTRA_CHARS.len();
766 let id = id / EXTRA_CHARS.len();
767 let extra2 = id % EXTRA_CHARS.len();
768 let id = id / EXTRA_CHARS.len();
769 let extra3 = id % EXTRA_CHARS.len();
770 hash.push_char(EXTRA_CHARS.as_bytes()[extra1] as char);
771 hash.push_char(EXTRA_CHARS.as_bytes()[extra2] as char);
772 hash.push_char(EXTRA_CHARS.as_bytes()[extra3] as char);
774 exported_name(path, hash.as_slice())
777 pub fn mangle_internal_name_by_type_and_seq(ccx: &CrateContext,
779 name: &str) -> String {
780 let s = ppaux::ty_to_string(ccx.tcx(), t);
781 let path = [PathName(token::intern(s.as_slice())),
783 let hash = get_symbol_hash(ccx, t);
784 mangle(ast_map::Values(path.iter()), Some(hash.as_slice()))
787 pub fn mangle_internal_name_by_path_and_seq(path: PathElems, flav: &str) -> String {
788 mangle(path.chain(Some(gensym_name(flav)).move_iter()), None)
791 pub fn get_cc_prog(sess: &Session) -> String {
792 match sess.opts.cg.linker {
793 Some(ref linker) => return linker.to_string(),
797 // In the future, FreeBSD will use clang as default compiler.
798 // It would be flexible to use cc (system's default C compiler)
799 // instead of hard-coded gcc.
800 // For win32, there is no cc command, so we add a condition to make it use gcc.
801 match sess.targ_cfg.os {
802 abi::OsWin32 => "gcc",
807 pub fn get_ar_prog(sess: &Session) -> String {
808 match sess.opts.cg.ar {
809 Some(ref ar) => (*ar).clone(),
810 None => "ar".to_string()
814 fn remove(sess: &Session, path: &Path) {
815 match fs::unlink(path) {
818 sess.err(format!("failed to remove {}: {}",
825 /// Perform the linkage portion of the compilation phase. This will generate all
826 /// of the requested outputs for this compilation session.
827 pub fn link_binary(sess: &Session,
828 trans: &CrateTranslation,
829 outputs: &OutputFilenames,
830 crate_name: &str) -> Vec<Path> {
831 let mut out_filenames = Vec::new();
832 for &crate_type in sess.crate_types.borrow().iter() {
833 if invalid_output_for_target(sess, crate_type) {
834 sess.bug(format!("invalid output type `{}` for target os `{}`",
835 crate_type, sess.targ_cfg.os).as_slice());
837 let out_file = link_binary_output(sess, trans, crate_type, outputs,
839 out_filenames.push(out_file);
842 // Remove the temporary object file and metadata if we aren't saving temps
843 if !sess.opts.cg.save_temps {
844 let obj_filename = outputs.temp_path(OutputTypeObject);
845 if !sess.opts.output_types.contains(&OutputTypeObject) {
846 remove(sess, &obj_filename);
848 remove(sess, &obj_filename.with_extension("metadata.o"));
855 /// Returns default crate type for target
857 /// Default crate type is used when crate type isn't provided neither
858 /// through cmd line arguments nor through crate attributes
860 /// It is CrateTypeExecutable for all platforms but iOS as there is no
861 /// way to run iOS binaries anyway without jailbreaking and
862 /// interaction with Rust code through static library is the only
864 pub fn default_output_for_target(sess: &Session) -> config::CrateType {
865 match sess.targ_cfg.os {
866 abi::OsiOS => config::CrateTypeStaticlib,
867 _ => config::CrateTypeExecutable
871 /// Checks if target supports crate_type as output
872 pub fn invalid_output_for_target(sess: &Session,
873 crate_type: config::CrateType) -> bool {
874 match (sess.targ_cfg.os, crate_type) {
875 (abi::OsiOS, config::CrateTypeDylib) => true,
880 fn is_writeable(p: &Path) -> bool {
883 Ok(m) => m.perm & io::UserWrite == io::UserWrite
887 pub fn filename_for_input(sess: &Session,
888 crate_type: config::CrateType,
890 out_filename: &Path) -> Path {
891 let libname = format!("{}{}", name, sess.opts.cg.extra_filename);
893 config::CrateTypeRlib => {
894 out_filename.with_filename(format!("lib{}.rlib", libname))
896 config::CrateTypeDylib => {
897 let (prefix, suffix) = match sess.targ_cfg.os {
898 abi::OsWin32 => (loader::WIN32_DLL_PREFIX, loader::WIN32_DLL_SUFFIX),
899 abi::OsMacos => (loader::MACOS_DLL_PREFIX, loader::MACOS_DLL_SUFFIX),
900 abi::OsLinux => (loader::LINUX_DLL_PREFIX, loader::LINUX_DLL_SUFFIX),
901 abi::OsAndroid => (loader::ANDROID_DLL_PREFIX, loader::ANDROID_DLL_SUFFIX),
902 abi::OsFreebsd => (loader::FREEBSD_DLL_PREFIX, loader::FREEBSD_DLL_SUFFIX),
903 abi::OsiOS => unreachable!(),
905 out_filename.with_filename(format!("{}{}{}",
910 config::CrateTypeStaticlib => {
911 out_filename.with_filename(format!("lib{}.a", libname))
913 config::CrateTypeExecutable => out_filename.clone(),
917 fn link_binary_output(sess: &Session,
918 trans: &CrateTranslation,
919 crate_type: config::CrateType,
920 outputs: &OutputFilenames,
921 crate_name: &str) -> Path {
922 let obj_filename = outputs.temp_path(OutputTypeObject);
923 let out_filename = match outputs.single_output_file {
924 Some(ref file) => file.clone(),
926 let out_filename = outputs.path(OutputTypeExe);
927 filename_for_input(sess, crate_type, crate_name, &out_filename)
931 // Make sure the output and obj_filename are both writeable.
932 // Mac, FreeBSD, and Windows system linkers check this already --
933 // however, the Linux linker will happily overwrite a read-only file.
934 // We should be consistent.
935 let obj_is_writeable = is_writeable(&obj_filename);
936 let out_is_writeable = is_writeable(&out_filename);
937 if !out_is_writeable {
938 sess.fatal(format!("output file {} is not writeable -- check its \
940 out_filename.display()).as_slice());
942 else if !obj_is_writeable {
943 sess.fatal(format!("object file {} is not writeable -- check its \
945 obj_filename.display()).as_slice());
949 config::CrateTypeRlib => {
950 link_rlib(sess, Some(trans), &obj_filename, &out_filename);
952 config::CrateTypeStaticlib => {
953 link_staticlib(sess, &obj_filename, &out_filename);
955 config::CrateTypeExecutable => {
956 link_natively(sess, trans, false, &obj_filename, &out_filename);
958 config::CrateTypeDylib => {
959 link_natively(sess, trans, true, &obj_filename, &out_filename);
968 // An rlib in its current incarnation is essentially a renamed .a file. The
969 // rlib primarily contains the object file of the crate, but it also contains
970 // all of the object files from native libraries. This is done by unzipping
971 // native libraries and inserting all of the contents into this archive.
972 fn link_rlib<'a>(sess: &'a Session,
973 trans: Option<&CrateTranslation>, // None == no metadata/bytecode
975 out_filename: &Path) -> Archive<'a> {
976 let mut a = Archive::create(sess, out_filename, obj_filename);
978 for &(ref l, kind) in sess.cstore.get_used_libraries().borrow().iter() {
980 cstore::NativeStatic => {
981 a.add_native_library(l.as_slice()).unwrap();
983 cstore::NativeFramework | cstore::NativeUnknown => {}
987 // Note that it is important that we add all of our non-object "magical
988 // files" *after* all of the object files in the archive. The reason for
989 // this is as follows:
991 // * When performing LTO, this archive will be modified to remove
992 // obj_filename from above. The reason for this is described below.
994 // * When the system linker looks at an archive, it will attempt to
995 // determine the architecture of the archive in order to see whether its
998 // The algorithm for this detection is: iterate over the files in the
999 // archive. Skip magical SYMDEF names. Interpret the first file as an
1000 // object file. Read architecture from the object file.
1002 // * As one can probably see, if "metadata" and "foo.bc" were placed
1003 // before all of the objects, then the architecture of this archive would
1004 // not be correctly inferred once 'foo.o' is removed.
1006 // Basically, all this means is that this code should not move above the
1010 // Instead of putting the metadata in an object file section, rlibs
1011 // contain the metadata in a separate file. We use a temp directory
1012 // here so concurrent builds in the same directory don't try to use
1013 // the same filename for metadata (stomping over one another)
1014 let tmpdir = TempDir::new("rustc").expect("needs a temp dir");
1015 let metadata = tmpdir.path().join(METADATA_FILENAME);
1016 match fs::File::create(&metadata).write(trans.metadata
1020 sess.err(format!("failed to write {}: {}",
1023 sess.abort_if_errors();
1026 a.add_file(&metadata, false);
1027 remove(sess, &metadata);
1029 // For LTO purposes, the bytecode of this library is also inserted
1030 // into the archive.
1032 // Note that we make sure that the bytecode filename in the archive
1033 // is never exactly 16 bytes long by adding a 16 byte extension to
1034 // it. This is to work around a bug in LLDB that would cause it to
1035 // crash if the name of a file in an archive was exactly 16 bytes.
1036 let bc = obj_filename.with_extension("bc");
1037 let bc_deflated = obj_filename.with_extension("bytecode.deflate");
1038 match fs::File::open(&bc).read_to_end().and_then(|data| {
1039 fs::File::create(&bc_deflated)
1040 .write(match flate::deflate_bytes(data.as_slice()) {
1041 Some(compressed) => compressed,
1042 None => sess.fatal("failed to compress bytecode")
1047 sess.err(format!("failed to write compressed bytecode: \
1050 sess.abort_if_errors()
1053 a.add_file(&bc_deflated, false);
1054 remove(sess, &bc_deflated);
1055 if !sess.opts.cg.save_temps &&
1056 !sess.opts.output_types.contains(&OutputTypeBitcode) {
1060 // After adding all files to the archive, we need to update the
1061 // symbol table of the archive. This currently dies on OSX (see
1062 // #11162), and isn't necessary there anyway
1063 match sess.targ_cfg.os {
1064 abi::OsMacos | abi::OsiOS => {}
1065 _ => { a.update_symbols(); }
1074 // Create a static archive
1076 // This is essentially the same thing as an rlib, but it also involves adding
1077 // all of the upstream crates' objects into the archive. This will slurp in
1078 // all of the native libraries of upstream dependencies as well.
1080 // Additionally, there's no way for us to link dynamic libraries, so we warn
1081 // about all dynamic library dependencies that they're not linked in.
1083 // There's no need to include metadata in a static archive, so ensure to not
1084 // link in the metadata object file (and also don't prepare the archive with a
1086 fn link_staticlib(sess: &Session, obj_filename: &Path, out_filename: &Path) {
1087 let mut a = link_rlib(sess, None, obj_filename, out_filename);
1088 a.add_native_library("morestack").unwrap();
1089 a.add_native_library("compiler-rt").unwrap();
1091 let crates = sess.cstore.get_used_crates(cstore::RequireStatic);
1092 let mut all_native_libs = vec![];
1094 for &(cnum, ref path) in crates.iter() {
1095 let name = sess.cstore.get_crate_data(cnum).name.clone();
1096 let p = match *path {
1097 Some(ref p) => p.clone(), None => {
1098 sess.err(format!("could not find rlib for: `{}`",
1103 a.add_rlib(&p, name.as_slice(), sess.lto()).unwrap();
1105 let native_libs = csearch::get_native_libraries(&sess.cstore, cnum);
1106 all_native_libs.extend(native_libs.move_iter());
1109 if !all_native_libs.is_empty() {
1110 sess.warn("link against the following native artifacts when linking against \
1111 this static library");
1112 sess.note("the order and any duplication can be significant on some platforms, \
1113 and so may need to be preserved");
1116 for &(kind, ref lib) in all_native_libs.iter() {
1117 let name = match kind {
1118 cstore::NativeStatic => "static library",
1119 cstore::NativeUnknown => "library",
1120 cstore::NativeFramework => "framework",
1122 sess.note(format!("{}: {}", name, *lib).as_slice());
1126 // Create a dynamic library or executable
1128 // This will invoke the system linker/cc to create the resulting file. This
1129 // links to all upstream files as well.
1130 fn link_natively(sess: &Session, trans: &CrateTranslation, dylib: bool,
1131 obj_filename: &Path, out_filename: &Path) {
1132 let tmpdir = TempDir::new("rustc").expect("needs a temp dir");
1134 // The invocations of cc share some flags across platforms
1135 let pname = get_cc_prog(sess);
1136 let mut cmd = Command::new(pname.as_slice());
1138 cmd.args(sess.targ_cfg.target_strs.cc_args.as_slice());
1139 link_args(&mut cmd, sess, dylib, tmpdir.path(),
1140 trans, obj_filename, out_filename);
1142 if (sess.opts.debugging_opts & config::PRINT_LINK_ARGS) != 0 {
1143 println!("{}", &cmd);
1146 // May have not found libraries in the right formats.
1147 sess.abort_if_errors();
1149 // Invoke the system linker
1151 let prog = time(sess.time_passes(), "running linker", (), |()| cmd.output());
1154 if !prog.status.success() {
1155 sess.err(format!("linking with `{}` failed: {}",
1157 prog.status).as_slice());
1158 sess.note(format!("{}", &cmd).as_slice());
1159 let mut output = prog.error.clone();
1160 output.push_all(prog.output.as_slice());
1161 sess.note(str::from_utf8(output.as_slice()).unwrap()
1163 sess.abort_if_errors();
1167 sess.err(format!("could not exec the linker `{}`: {}",
1170 sess.abort_if_errors();
1175 // On OSX, debuggers need this utility to get run to do some munging of
1177 if (sess.targ_cfg.os == abi::OsMacos || sess.targ_cfg.os == abi::OsiOS)
1178 && (sess.opts.debuginfo != NoDebugInfo) {
1179 match Command::new("dsymutil").arg(out_filename).status() {
1182 sess.err(format!("failed to run dsymutil: {}", e).as_slice());
1183 sess.abort_if_errors();
1189 fn link_args(cmd: &mut Command,
1193 trans: &CrateTranslation,
1194 obj_filename: &Path,
1195 out_filename: &Path) {
1197 // The default library location, we need this to find the runtime.
1198 // The location of crates will be determined as needed.
1199 let lib_path = sess.target_filesearch().get_lib_path();
1200 cmd.arg("-L").arg(&lib_path);
1202 cmd.arg("-o").arg(out_filename).arg(obj_filename);
1204 // Stack growth requires statically linking a __morestack function. Note
1205 // that this is listed *before* all other libraries. Due to the usage of the
1206 // --as-needed flag below, the standard library may only be useful for its
1207 // rust_stack_exhausted function. In this case, we must ensure that the
1208 // libmorestack.a file appears *before* the standard library (so we put it
1209 // at the very front).
1211 // Most of the time this is sufficient, except for when LLVM gets super
1212 // clever. If, for example, we have a main function `fn main() {}`, LLVM
1213 // will optimize out calls to `__morestack` entirely because the function
1214 // doesn't need any stack at all!
1216 // To get around this snag, we specially tell the linker to always include
1217 // all contents of this library. This way we're guaranteed that the linker
1218 // will include the __morestack symbol 100% of the time, always resolving
1219 // references to it even if the object above didn't use it.
1220 match sess.targ_cfg.os {
1221 abi::OsMacos | abi::OsiOS => {
1222 let morestack = lib_path.join("libmorestack.a");
1224 let mut v = "-Wl,-force_load,".as_bytes().to_owned();
1225 v.push_all(morestack.as_vec());
1226 cmd.arg(v.as_slice());
1229 cmd.args(["-Wl,--whole-archive", "-lmorestack",
1230 "-Wl,--no-whole-archive"]);
1234 // When linking a dynamic library, we put the metadata into a section of the
1235 // executable. This metadata is in a separate object file from the main
1236 // object file, so we link that in here.
1238 cmd.arg(obj_filename.with_extension("metadata.o"));
1241 // We want to prevent the compiler from accidentally leaking in any system
1242 // libraries, so we explicitly ask gcc to not link to any libraries by
1243 // default. Note that this does not happen for windows because windows pulls
1244 // in some large number of libraries and I couldn't quite figure out which
1245 // subset we wanted.
1247 // FIXME(#11937) we should invoke the system linker directly
1248 if sess.targ_cfg.os != abi::OsWin32 {
1249 cmd.arg("-nodefaultlibs");
1252 // If we're building a dylib, we don't use --gc-sections because LLVM has
1253 // already done the best it can do, and we also don't want to eliminate the
1254 // metadata. If we're building an executable, however, --gc-sections drops
1255 // the size of hello world from 1.8MB to 597K, a 67% reduction.
1256 if !dylib && sess.targ_cfg.os != abi::OsMacos && sess.targ_cfg.os != abi::OsiOS {
1257 cmd.arg("-Wl,--gc-sections");
1260 if sess.targ_cfg.os == abi::OsLinux {
1261 // GNU-style linkers will use this to omit linking to libraries which
1262 // don't actually fulfill any relocations, but only for libraries which
1263 // follow this flag. Thus, use it before specifying libraries to link to.
1264 cmd.arg("-Wl,--as-needed");
1266 // GNU-style linkers support optimization with -O. GNU ld doesn't need a
1267 // numeric argument, but other linkers do.
1268 if sess.opts.optimize == config::Default ||
1269 sess.opts.optimize == config::Aggressive {
1272 } else if sess.targ_cfg.os == abi::OsMacos || sess.targ_cfg.os == abi::OsiOS {
1273 // The dead_strip option to the linker specifies that functions and data
1274 // unreachable by the entry point will be removed. This is quite useful
1275 // with Rust's compilation model of compiling libraries at a time into
1276 // one object file. For example, this brings hello world from 1.7MB to
1279 // Note that this is done for both executables and dynamic libraries. We
1280 // won't get much benefit from dylibs because LLVM will have already
1281 // stripped away as much as it could. This has not been seen to impact
1282 // link times negatively.
1283 cmd.arg("-Wl,-dead_strip");
1286 if sess.targ_cfg.os == abi::OsWin32 {
1287 // Make sure that we link to the dynamic libgcc, otherwise cross-module
1288 // DWARF stack unwinding will not work.
1289 // This behavior may be overridden by --link-args "-static-libgcc"
1290 cmd.arg("-shared-libgcc");
1292 // And here, we see obscure linker flags #45. On windows, it has been
1293 // found to be necessary to have this flag to compile liblibc.
1295 // First a bit of background. On Windows, the file format is not ELF,
1296 // but COFF (at least according to LLVM). COFF doesn't officially allow
1297 // for section names over 8 characters, apparently. Our metadata
1298 // section, ".note.rustc", you'll note is over 8 characters.
1300 // On more recent versions of gcc on mingw, apparently the section name
1301 // is *not* truncated, but rather stored elsewhere in a separate lookup
1302 // table. On older versions of gcc, they apparently always truncated the
1303 // section names (at least in some cases). Truncating the section name
1304 // actually creates "invalid" objects [1] [2], but only for some
1305 // introspection tools, not in terms of whether it can be loaded.
1307 // Long story short, passing this flag forces the linker to *not*
1308 // truncate section names (so we can find the metadata section after
1309 // it's compiled). The real kicker is that rust compiled just fine on
1310 // windows for quite a long time *without* this flag, so I have no idea
1311 // why it suddenly started failing for liblibc. Regardless, we
1312 // definitely don't want section name truncation, so we're keeping this
1313 // flag for windows.
1315 // [1] - https://sourceware.org/bugzilla/show_bug.cgi?id=13130
1316 // [2] - https://code.google.com/p/go/issues/detail?id=2139
1317 cmd.arg("-Wl,--enable-long-section-names");
1320 if sess.targ_cfg.os == abi::OsAndroid {
1321 // Many of the symbols defined in compiler-rt are also defined in libgcc.
1322 // Android linker doesn't like that by default.
1323 cmd.arg("-Wl,--allow-multiple-definition");
1326 // Take careful note of the ordering of the arguments we pass to the linker
1327 // here. Linkers will assume that things on the left depend on things to the
1328 // right. Things on the right cannot depend on things on the left. This is
1329 // all formally implemented in terms of resolving symbols (libs on the right
1330 // resolve unknown symbols of libs on the left, but not vice versa).
1332 // For this reason, we have organized the arguments we pass to the linker as
1335 // 1. The local object that LLVM just generated
1336 // 2. Upstream rust libraries
1337 // 3. Local native libraries
1338 // 4. Upstream native libraries
1340 // This is generally fairly natural, but some may expect 2 and 3 to be
1341 // swapped. The reason that all native libraries are put last is that it's
1342 // not recommended for a native library to depend on a symbol from a rust
1343 // crate. If this is the case then a staticlib crate is recommended, solving
1346 // Additionally, it is occasionally the case that upstream rust libraries
1347 // depend on a local native library. In the case of libraries such as
1348 // lua/glfw/etc the name of the library isn't the same across all platforms,
1349 // so only the consumer crate of a library knows the actual name. This means
1350 // that downstream crates will provide the #[link] attribute which upstream
1351 // crates will depend on. Hence local native libraries are after out
1352 // upstream rust crates.
1354 // In theory this means that a symbol in an upstream native library will be
1355 // shadowed by a local native library when it wouldn't have been before, but
1356 // this kind of behavior is pretty platform specific and generally not
1357 // recommended anyway, so I don't think we're shooting ourself in the foot
1359 add_upstream_rust_crates(cmd, sess, dylib, tmpdir, trans);
1360 add_local_native_libraries(cmd, sess);
1361 add_upstream_native_libraries(cmd, sess);
1363 // # Telling the linker what we're doing
1366 // On mac we need to tell the linker to let this library be rpathed
1367 if sess.targ_cfg.os == abi::OsMacos {
1368 cmd.args(["-dynamiclib", "-Wl,-dylib"]);
1370 if sess.opts.cg.rpath {
1371 let mut v = Vec::from_slice("-Wl,-install_name,@rpath/".as_bytes());
1372 v.push_all(out_filename.filename().unwrap());
1373 cmd.arg(v.as_slice());
1380 if sess.targ_cfg.os == abi::OsFreebsd {
1381 cmd.args(["-L/usr/local/lib",
1382 "-L/usr/local/lib/gcc46",
1383 "-L/usr/local/lib/gcc44"]);
1386 // FIXME (#2397): At some point we want to rpath our guesses as to
1387 // where extern libraries might live, based on the
1388 // addl_lib_search_paths
1389 if sess.opts.cg.rpath {
1390 cmd.args(rpath::get_rpath_flags(sess, out_filename).as_slice());
1393 // compiler-rt contains implementations of low-level LLVM helpers. This is
1394 // used to resolve symbols from the object file we just created, as well as
1395 // any system static libraries that may be expecting gcc instead. Most
1396 // symbols in libgcc also appear in compiler-rt.
1398 // This is the end of the command line, so this library is used to resolve
1399 // *all* undefined symbols in all other libraries, and this is intentional.
1400 cmd.arg("-lcompiler-rt");
1402 // Finally add all the linker arguments provided on the command line along
1403 // with any #[link_args] attributes found inside the crate
1404 cmd.args(sess.opts.cg.link_args.as_slice());
1405 for arg in sess.cstore.get_used_link_args().borrow().iter() {
1406 cmd.arg(arg.as_slice());
1410 // # Native library linking
1412 // User-supplied library search paths (-L on the command line). These are
1413 // the same paths used to find Rust crates, so some of them may have been
1414 // added already by the previous crate linking code. This only allows them
1415 // to be found at compile time so it is still entirely up to outside
1416 // forces to make sure that library can be found at runtime.
1418 // Also note that the native libraries linked here are only the ones located
1419 // in the current crate. Upstream crates with native library dependencies
1420 // may have their native library pulled in above.
1421 fn add_local_native_libraries(cmd: &mut Command, sess: &Session) {
1422 for path in sess.opts.addl_lib_search_paths.borrow().iter() {
1423 cmd.arg("-L").arg(path);
1426 let rustpath = filesearch::rust_path();
1427 for path in rustpath.iter() {
1428 cmd.arg("-L").arg(path);
1431 // Some platforms take hints about whether a library is static or dynamic.
1432 // For those that support this, we ensure we pass the option if the library
1433 // was flagged "static" (most defaults are dynamic) to ensure that if
1434 // libfoo.a and libfoo.so both exist that the right one is chosen.
1435 let takes_hints = sess.targ_cfg.os != abi::OsMacos && sess.targ_cfg.os != abi::OsiOS;
1437 for &(ref l, kind) in sess.cstore.get_used_libraries().borrow().iter() {
1439 cstore::NativeUnknown | cstore::NativeStatic => {
1441 if kind == cstore::NativeStatic {
1442 cmd.arg("-Wl,-Bstatic");
1444 cmd.arg("-Wl,-Bdynamic");
1447 cmd.arg(format!("-l{}", *l));
1449 cstore::NativeFramework => {
1450 cmd.arg("-framework");
1451 cmd.arg(l.as_slice());
1456 cmd.arg("-Wl,-Bdynamic");
1460 // # Rust Crate linking
1462 // Rust crates are not considered at all when creating an rlib output. All
1463 // dependencies will be linked when producing the final output (instead of
1464 // the intermediate rlib version)
1465 fn add_upstream_rust_crates(cmd: &mut Command, sess: &Session,
1466 dylib: bool, tmpdir: &Path,
1467 trans: &CrateTranslation) {
1468 // All of the heavy lifting has previously been accomplished by the
1469 // dependency_format module of the compiler. This is just crawling the
1470 // output of that module, adding crates as necessary.
1472 // Linking to a rlib involves just passing it to the linker (the linker
1473 // will slurp up the object files inside), and linking to a dynamic library
1474 // involves just passing the right -l flag.
1476 let data = if dylib {
1477 trans.crate_formats.get(&config::CrateTypeDylib)
1479 trans.crate_formats.get(&config::CrateTypeExecutable)
1482 // Invoke get_used_crates to ensure that we get a topological sorting of
1484 let deps = sess.cstore.get_used_crates(cstore::RequireDynamic);
1486 for &(cnum, _) in deps.iter() {
1487 // We may not pass all crates through to the linker. Some crates may
1488 // appear statically in an existing dylib, meaning we'll pick up all the
1489 // symbols from the dylib.
1490 let kind = match *data.get(cnum as uint - 1) {
1494 let src = sess.cstore.get_used_crate_source(cnum).unwrap();
1496 cstore::RequireDynamic => {
1497 add_dynamic_crate(cmd, sess, src.dylib.unwrap())
1499 cstore::RequireStatic => {
1500 add_static_crate(cmd, sess, tmpdir, cnum, src.rlib.unwrap())
1506 // Converts a library file-stem into a cc -l argument
1507 fn unlib<'a>(config: &config::Config, stem: &'a [u8]) -> &'a [u8] {
1508 if stem.starts_with("lib".as_bytes()) && config.os != abi::OsWin32 {
1515 // Adds the static "rlib" versions of all crates to the command line.
1516 fn add_static_crate(cmd: &mut Command, sess: &Session, tmpdir: &Path,
1517 cnum: ast::CrateNum, cratepath: Path) {
1518 // When performing LTO on an executable output, all of the
1519 // bytecode from the upstream libraries has already been
1520 // included in our object file output. We need to modify all of
1521 // the upstream archives to remove their corresponding object
1522 // file to make sure we don't pull the same code in twice.
1524 // We must continue to link to the upstream archives to be sure
1525 // to pull in native static dependencies. As the final caveat,
1526 // on linux it is apparently illegal to link to a blank archive,
1527 // so if an archive no longer has any object files in it after
1528 // we remove `lib.o`, then don't link against it at all.
1530 // If we're not doing LTO, then our job is simply to just link
1531 // against the archive.
1533 let name = sess.cstore.get_crate_data(cnum).name.clone();
1534 time(sess.time_passes(),
1535 format!("altering {}.rlib", name).as_slice(),
1537 let dst = tmpdir.join(cratepath.filename().unwrap());
1538 match fs::copy(&cratepath, &dst) {
1541 sess.err(format!("failed to copy {} to {}: {}",
1542 cratepath.display(),
1545 sess.abort_if_errors();
1548 let mut archive = Archive::open(sess, dst.clone());
1549 archive.remove_file(format!("{}.o", name).as_slice());
1550 let files = archive.files();
1551 if files.iter().any(|s| s.as_slice().ends_with(".o")) {
1560 // Same thing as above, but for dynamic crates instead of static crates.
1561 fn add_dynamic_crate(cmd: &mut Command, sess: &Session, cratepath: Path) {
1562 // If we're performing LTO, then it should have been previously required
1563 // that all upstream rust dependencies were available in an rlib format.
1564 assert!(!sess.lto());
1566 // Just need to tell the linker about where the library lives and
1568 let dir = cratepath.dirname();
1569 if !dir.is_empty() { cmd.arg("-L").arg(dir); }
1571 let mut v = Vec::from_slice("-l".as_bytes());
1572 v.push_all(unlib(&sess.targ_cfg, cratepath.filestem().unwrap()));
1573 cmd.arg(v.as_slice());
1577 // Link in all of our upstream crates' native dependencies. Remember that
1578 // all of these upstream native dependencies are all non-static
1579 // dependencies. We've got two cases then:
1581 // 1. The upstream crate is an rlib. In this case we *must* link in the
1582 // native dependency because the rlib is just an archive.
1584 // 2. The upstream crate is a dylib. In order to use the dylib, we have to
1585 // have the dependency present on the system somewhere. Thus, we don't
1586 // gain a whole lot from not linking in the dynamic dependency to this
1589 // The use case for this is a little subtle. In theory the native
1590 // dependencies of a crate are purely an implementation detail of the crate
1591 // itself, but the problem arises with generic and inlined functions. If a
1592 // generic function calls a native function, then the generic function must
1593 // be instantiated in the target crate, meaning that the native symbol must
1594 // also be resolved in the target crate.
1595 fn add_upstream_native_libraries(cmd: &mut Command, sess: &Session) {
1596 // Be sure to use a topological sorting of crates because there may be
1597 // interdependencies between native libraries. When passing -nodefaultlibs,
1598 // for example, almost all native libraries depend on libc, so we have to
1599 // make sure that's all the way at the right (liblibc is near the base of
1600 // the dependency chain).
1602 // This passes RequireStatic, but the actual requirement doesn't matter,
1603 // we're just getting an ordering of crate numbers, we're not worried about
1605 let crates = sess.cstore.get_used_crates(cstore::RequireStatic);
1606 for (cnum, _) in crates.move_iter() {
1607 let libs = csearch::get_native_libraries(&sess.cstore, cnum);
1608 for &(kind, ref lib) in libs.iter() {
1610 cstore::NativeUnknown => {
1611 cmd.arg(format!("-l{}", *lib));
1613 cstore::NativeFramework => {
1614 cmd.arg("-framework");
1615 cmd.arg(lib.as_slice());
1617 cstore::NativeStatic => {
1618 sess.bug("statics shouldn't be propagated");