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);
560 match sess.opts.crate_name {
561 Some(ref s) => return validate(s.clone(), None),
568 let crate_name = attrs.iter().find(|at| at.check_name("crate_name"))
569 .and_then(|at| at.value_str().map(|s| (at, s)));
571 Some((attr, s)) => return validate(s.get().to_string(), Some(attr.span)),
574 let crate_id = attrs.iter().find(|at| at.check_name("crate_id"))
575 .and_then(|at| at.value_str().map(|s| (at, s)))
576 .and_then(|(at, s)| {
577 from_str::<CrateId>(s.get()).map(|id| (at, id))
580 Some((attr, id)) => {
583 sess.span_warn(attr.span, "the #[crate_id] attribute is \
585 #[crate_name] attribute");
589 return validate(id.name, Some(attr.span))
594 FileInput(ref path) => {
595 match path.filestem_str() {
596 Some(s) => return validate(s.to_string(), None),
603 "rust-out".to_string()
606 pub fn build_link_meta(sess: &Session, krate: &ast::Crate,
607 name: String) -> LinkMeta {
610 crate_hash: Svh::calculate(sess, krate),
616 fn truncated_hash_result(symbol_hasher: &mut Sha256) -> String {
617 let output = symbol_hasher.result_bytes();
618 // 64 bits should be enough to avoid collisions.
619 output.slice_to(8).to_hex().to_string()
623 // This calculates STH for a symbol, as defined above
624 fn symbol_hash(tcx: &ty::ctxt,
625 symbol_hasher: &mut Sha256,
627 link_meta: &LinkMeta)
629 // NB: do *not* use abbrevs here as we want the symbol names
630 // to be independent of one another in the crate.
632 symbol_hasher.reset();
633 symbol_hasher.input_str(link_meta.crate_name.as_slice());
634 symbol_hasher.input_str("-");
635 symbol_hasher.input_str(link_meta.crate_hash.as_str());
636 for meta in tcx.sess.crate_metadata.borrow().iter() {
637 symbol_hasher.input_str(meta.as_slice());
639 symbol_hasher.input_str("-");
640 symbol_hasher.input_str(encoder::encoded_ty(tcx, t).as_slice());
641 // Prefix with 'h' so that it never blends into adjacent digits
642 let mut hash = String::from_str("h");
643 hash.push_str(truncated_hash_result(symbol_hasher).as_slice());
647 fn get_symbol_hash(ccx: &CrateContext, t: ty::t) -> String {
648 match ccx.type_hashcodes.borrow().find(&t) {
649 Some(h) => return h.to_string(),
653 let mut symbol_hasher = ccx.symbol_hasher.borrow_mut();
654 let hash = symbol_hash(ccx.tcx(), &mut *symbol_hasher, t, &ccx.link_meta);
655 ccx.type_hashcodes.borrow_mut().insert(t, hash.clone());
660 // Name sanitation. LLVM will happily accept identifiers with weird names, but
662 // gas accepts the following characters in symbols: a-z, A-Z, 0-9, ., _, $
663 pub fn sanitize(s: &str) -> String {
664 let mut result = String::new();
667 // Escape these with $ sequences
668 '@' => result.push_str("$SP$"),
669 '~' => result.push_str("$UP$"),
670 '*' => result.push_str("$RP$"),
671 '&' => result.push_str("$BP$"),
672 '<' => result.push_str("$LT$"),
673 '>' => result.push_str("$GT$"),
674 '(' => result.push_str("$LP$"),
675 ')' => result.push_str("$RP$"),
676 ',' => result.push_str("$C$"),
678 // '.' doesn't occur in types and functions, so reuse it
680 '-' | ':' => result.push_char('.'),
682 // These are legal symbols
686 | '_' | '.' | '$' => result.push_char(c),
689 let mut tstr = String::new();
690 char::escape_unicode(c, |c| tstr.push_char(c));
691 result.push_char('$');
692 result.push_str(tstr.as_slice().slice_from(1));
697 // Underscore-qualify anything that didn't start as an ident.
698 if result.len() > 0u &&
699 result.as_bytes()[0] != '_' as u8 &&
700 ! char::is_XID_start(result.as_bytes()[0] as char) {
701 return format!("_{}", result.as_slice());
707 pub fn mangle<PI: Iterator<PathElem>>(mut path: PI,
708 hash: Option<&str>) -> String {
709 // Follow C++ namespace-mangling style, see
710 // http://en.wikipedia.org/wiki/Name_mangling for more info.
712 // It turns out that on OSX you can actually have arbitrary symbols in
713 // function names (at least when given to LLVM), but this is not possible
714 // when using unix's linker. Perhaps one day when we just use a linker from LLVM
715 // we won't need to do this name mangling. The problem with name mangling is
716 // that it seriously limits the available characters. For example we can't
717 // have things like &T or ~[T] in symbol names when one would theoretically
718 // want them for things like impls of traits on that type.
720 // To be able to work on all platforms and get *some* reasonable output, we
721 // use C++ name-mangling.
723 let mut n = String::from_str("_ZN"); // _Z == Begin name-sequence, N == nested
725 fn push(n: &mut String, s: &str) {
726 let sani = sanitize(s);
727 n.push_str(format!("{}{}", sani.len(), sani).as_slice());
730 // First, connect each component with <len, name> pairs.
732 push(&mut n, token::get_name(e.name()).get().as_slice())
736 Some(s) => push(&mut n, s),
740 n.push_char('E'); // End name-sequence.
744 pub fn exported_name(path: PathElems, hash: &str) -> String {
745 mangle(path, Some(hash))
748 pub fn mangle_exported_name(ccx: &CrateContext, path: PathElems,
749 t: ty::t, id: ast::NodeId) -> String {
750 let mut hash = get_symbol_hash(ccx, t);
752 // Paths can be completely identical for different nodes,
753 // e.g. `fn foo() { { fn a() {} } { fn a() {} } }`, so we
754 // generate unique characters from the node id. For now
755 // hopefully 3 characters is enough to avoid collisions.
756 static EXTRA_CHARS: &'static str =
757 "abcdefghijklmnopqrstuvwxyz\
758 ABCDEFGHIJKLMNOPQRSTUVWXYZ\
761 let extra1 = id % EXTRA_CHARS.len();
762 let id = id / EXTRA_CHARS.len();
763 let extra2 = id % EXTRA_CHARS.len();
764 let id = id / EXTRA_CHARS.len();
765 let extra3 = id % EXTRA_CHARS.len();
766 hash.push_char(EXTRA_CHARS.as_bytes()[extra1] as char);
767 hash.push_char(EXTRA_CHARS.as_bytes()[extra2] as char);
768 hash.push_char(EXTRA_CHARS.as_bytes()[extra3] as char);
770 exported_name(path, hash.as_slice())
773 pub fn mangle_internal_name_by_type_and_seq(ccx: &CrateContext,
775 name: &str) -> String {
776 let s = ppaux::ty_to_string(ccx.tcx(), t);
777 let path = [PathName(token::intern(s.as_slice())),
779 let hash = get_symbol_hash(ccx, t);
780 mangle(ast_map::Values(path.iter()), Some(hash.as_slice()))
783 pub fn mangle_internal_name_by_path_and_seq(path: PathElems, flav: &str) -> String {
784 mangle(path.chain(Some(gensym_name(flav)).move_iter()), None)
787 pub fn get_cc_prog(sess: &Session) -> String {
788 match sess.opts.cg.linker {
789 Some(ref linker) => return linker.to_string(),
793 // In the future, FreeBSD will use clang as default compiler.
794 // It would be flexible to use cc (system's default C compiler)
795 // instead of hard-coded gcc.
796 // For win32, there is no cc command, so we add a condition to make it use gcc.
797 match sess.targ_cfg.os {
798 abi::OsWin32 => "gcc",
803 pub fn get_ar_prog(sess: &Session) -> String {
804 match sess.opts.cg.ar {
805 Some(ref ar) => (*ar).clone(),
806 None => "ar".to_string()
810 fn remove(sess: &Session, path: &Path) {
811 match fs::unlink(path) {
814 sess.err(format!("failed to remove {}: {}",
821 /// Perform the linkage portion of the compilation phase. This will generate all
822 /// of the requested outputs for this compilation session.
823 pub fn link_binary(sess: &Session,
824 trans: &CrateTranslation,
825 outputs: &OutputFilenames,
826 crate_name: &str) -> Vec<Path> {
827 let mut out_filenames = Vec::new();
828 for &crate_type in sess.crate_types.borrow().iter() {
829 if invalid_output_for_target(sess, crate_type) {
830 sess.bug(format!("invalid output type `{}` for target os `{}`",
831 crate_type, sess.targ_cfg.os).as_slice());
833 let out_file = link_binary_output(sess, trans, crate_type, outputs,
835 out_filenames.push(out_file);
838 // Remove the temporary object file and metadata if we aren't saving temps
839 if !sess.opts.cg.save_temps {
840 let obj_filename = outputs.temp_path(OutputTypeObject);
841 if !sess.opts.output_types.contains(&OutputTypeObject) {
842 remove(sess, &obj_filename);
844 remove(sess, &obj_filename.with_extension("metadata.o"));
851 /// Returns default crate type for target
853 /// Default crate type is used when crate type isn't provided neither
854 /// through cmd line arguments nor through crate attributes
856 /// It is CrateTypeExecutable for all platforms but iOS as there is no
857 /// way to run iOS binaries anyway without jailbreaking and
858 /// interaction with Rust code through static library is the only
860 pub fn default_output_for_target(sess: &Session) -> config::CrateType {
861 match sess.targ_cfg.os {
862 abi::OsiOS => config::CrateTypeStaticlib,
863 _ => config::CrateTypeExecutable
867 /// Checks if target supports crate_type as output
868 pub fn invalid_output_for_target(sess: &Session,
869 crate_type: config::CrateType) -> bool {
870 match (sess.targ_cfg.os, crate_type) {
871 (abi::OsiOS, config::CrateTypeDylib) => true,
876 fn is_writeable(p: &Path) -> bool {
879 Ok(m) => m.perm & io::UserWrite == io::UserWrite
883 pub fn filename_for_input(sess: &Session,
884 crate_type: config::CrateType,
886 out_filename: &Path) -> Path {
887 let libname = format!("{}{}", name, sess.opts.cg.extra_filename);
889 config::CrateTypeRlib => {
890 out_filename.with_filename(format!("lib{}.rlib", libname))
892 config::CrateTypeDylib => {
893 let (prefix, suffix) = match sess.targ_cfg.os {
894 abi::OsWin32 => (loader::WIN32_DLL_PREFIX, loader::WIN32_DLL_SUFFIX),
895 abi::OsMacos => (loader::MACOS_DLL_PREFIX, loader::MACOS_DLL_SUFFIX),
896 abi::OsLinux => (loader::LINUX_DLL_PREFIX, loader::LINUX_DLL_SUFFIX),
897 abi::OsAndroid => (loader::ANDROID_DLL_PREFIX, loader::ANDROID_DLL_SUFFIX),
898 abi::OsFreebsd => (loader::FREEBSD_DLL_PREFIX, loader::FREEBSD_DLL_SUFFIX),
899 abi::OsiOS => unreachable!(),
901 out_filename.with_filename(format!("{}{}{}",
906 config::CrateTypeStaticlib => {
907 out_filename.with_filename(format!("lib{}.a", libname))
909 config::CrateTypeExecutable => out_filename.clone(),
913 fn link_binary_output(sess: &Session,
914 trans: &CrateTranslation,
915 crate_type: config::CrateType,
916 outputs: &OutputFilenames,
917 crate_name: &str) -> Path {
918 let obj_filename = outputs.temp_path(OutputTypeObject);
919 let out_filename = match outputs.single_output_file {
920 Some(ref file) => file.clone(),
922 let out_filename = outputs.path(OutputTypeExe);
923 filename_for_input(sess, crate_type, crate_name, &out_filename)
927 // Make sure the output and obj_filename are both writeable.
928 // Mac, FreeBSD, and Windows system linkers check this already --
929 // however, the Linux linker will happily overwrite a read-only file.
930 // We should be consistent.
931 let obj_is_writeable = is_writeable(&obj_filename);
932 let out_is_writeable = is_writeable(&out_filename);
933 if !out_is_writeable {
934 sess.fatal(format!("output file {} is not writeable -- check its \
936 out_filename.display()).as_slice());
938 else if !obj_is_writeable {
939 sess.fatal(format!("object file {} is not writeable -- check its \
941 obj_filename.display()).as_slice());
945 config::CrateTypeRlib => {
946 link_rlib(sess, Some(trans), &obj_filename, &out_filename);
948 config::CrateTypeStaticlib => {
949 link_staticlib(sess, &obj_filename, &out_filename);
951 config::CrateTypeExecutable => {
952 link_natively(sess, trans, false, &obj_filename, &out_filename);
954 config::CrateTypeDylib => {
955 link_natively(sess, trans, true, &obj_filename, &out_filename);
964 // An rlib in its current incarnation is essentially a renamed .a file. The
965 // rlib primarily contains the object file of the crate, but it also contains
966 // all of the object files from native libraries. This is done by unzipping
967 // native libraries and inserting all of the contents into this archive.
968 fn link_rlib<'a>(sess: &'a Session,
969 trans: Option<&CrateTranslation>, // None == no metadata/bytecode
971 out_filename: &Path) -> Archive<'a> {
972 let mut a = Archive::create(sess, out_filename, obj_filename);
974 for &(ref l, kind) in sess.cstore.get_used_libraries().borrow().iter() {
976 cstore::NativeStatic => {
977 a.add_native_library(l.as_slice()).unwrap();
979 cstore::NativeFramework | cstore::NativeUnknown => {}
983 // Note that it is important that we add all of our non-object "magical
984 // files" *after* all of the object files in the archive. The reason for
985 // this is as follows:
987 // * When performing LTO, this archive will be modified to remove
988 // obj_filename from above. The reason for this is described below.
990 // * When the system linker looks at an archive, it will attempt to
991 // determine the architecture of the archive in order to see whether its
994 // The algorithm for this detection is: iterate over the files in the
995 // archive. Skip magical SYMDEF names. Interpret the first file as an
996 // object file. Read architecture from the object file.
998 // * As one can probably see, if "metadata" and "foo.bc" were placed
999 // before all of the objects, then the architecture of this archive would
1000 // not be correctly inferred once 'foo.o' is removed.
1002 // Basically, all this means is that this code should not move above the
1006 // Instead of putting the metadata in an object file section, rlibs
1007 // contain the metadata in a separate file. We use a temp directory
1008 // here so concurrent builds in the same directory don't try to use
1009 // the same filename for metadata (stomping over one another)
1010 let tmpdir = TempDir::new("rustc").expect("needs a temp dir");
1011 let metadata = tmpdir.path().join(METADATA_FILENAME);
1012 match fs::File::create(&metadata).write(trans.metadata
1016 sess.err(format!("failed to write {}: {}",
1019 sess.abort_if_errors();
1022 a.add_file(&metadata, false);
1023 remove(sess, &metadata);
1025 // For LTO purposes, the bytecode of this library is also inserted
1026 // into the archive.
1028 // Note that we make sure that the bytecode filename in the archive
1029 // is never exactly 16 bytes long by adding a 16 byte extension to
1030 // it. This is to work around a bug in LLDB that would cause it to
1031 // crash if the name of a file in an archive was exactly 16 bytes.
1032 let bc = obj_filename.with_extension("bc");
1033 let bc_deflated = obj_filename.with_extension("bytecode.deflate");
1034 match fs::File::open(&bc).read_to_end().and_then(|data| {
1035 fs::File::create(&bc_deflated)
1036 .write(match flate::deflate_bytes(data.as_slice()) {
1037 Some(compressed) => compressed,
1038 None => sess.fatal("failed to compress bytecode")
1043 sess.err(format!("failed to write compressed bytecode: \
1046 sess.abort_if_errors()
1049 a.add_file(&bc_deflated, false);
1050 remove(sess, &bc_deflated);
1051 if !sess.opts.cg.save_temps &&
1052 !sess.opts.output_types.contains(&OutputTypeBitcode) {
1056 // After adding all files to the archive, we need to update the
1057 // symbol table of the archive. This currently dies on OSX (see
1058 // #11162), and isn't necessary there anyway
1059 match sess.targ_cfg.os {
1060 abi::OsMacos | abi::OsiOS => {}
1061 _ => { a.update_symbols(); }
1070 // Create a static archive
1072 // This is essentially the same thing as an rlib, but it also involves adding
1073 // all of the upstream crates' objects into the archive. This will slurp in
1074 // all of the native libraries of upstream dependencies as well.
1076 // Additionally, there's no way for us to link dynamic libraries, so we warn
1077 // about all dynamic library dependencies that they're not linked in.
1079 // There's no need to include metadata in a static archive, so ensure to not
1080 // link in the metadata object file (and also don't prepare the archive with a
1082 fn link_staticlib(sess: &Session, obj_filename: &Path, out_filename: &Path) {
1083 let mut a = link_rlib(sess, None, obj_filename, out_filename);
1084 a.add_native_library("morestack").unwrap();
1085 a.add_native_library("compiler-rt").unwrap();
1087 let crates = sess.cstore.get_used_crates(cstore::RequireStatic);
1088 let mut all_native_libs = vec![];
1090 for &(cnum, ref path) in crates.iter() {
1091 let name = sess.cstore.get_crate_data(cnum).name.clone();
1092 let p = match *path {
1093 Some(ref p) => p.clone(), None => {
1094 sess.err(format!("could not find rlib for: `{}`",
1099 a.add_rlib(&p, name.as_slice(), sess.lto()).unwrap();
1101 let native_libs = csearch::get_native_libraries(&sess.cstore, cnum);
1102 all_native_libs.extend(native_libs.move_iter());
1105 if !all_native_libs.is_empty() {
1106 sess.warn("link against the following native artifacts when linking against \
1107 this static library");
1108 sess.note("the order and any duplication can be significant on some platforms, \
1109 and so may need to be preserved");
1112 for &(kind, ref lib) in all_native_libs.iter() {
1113 let name = match kind {
1114 cstore::NativeStatic => "static library",
1115 cstore::NativeUnknown => "library",
1116 cstore::NativeFramework => "framework",
1118 sess.note(format!("{}: {}", name, *lib).as_slice());
1122 // Create a dynamic library or executable
1124 // This will invoke the system linker/cc to create the resulting file. This
1125 // links to all upstream files as well.
1126 fn link_natively(sess: &Session, trans: &CrateTranslation, dylib: bool,
1127 obj_filename: &Path, out_filename: &Path) {
1128 let tmpdir = TempDir::new("rustc").expect("needs a temp dir");
1130 // The invocations of cc share some flags across platforms
1131 let pname = get_cc_prog(sess);
1132 let mut cmd = Command::new(pname.as_slice());
1134 cmd.args(sess.targ_cfg.target_strs.cc_args.as_slice());
1135 link_args(&mut cmd, sess, dylib, tmpdir.path(),
1136 trans, obj_filename, out_filename);
1138 if (sess.opts.debugging_opts & config::PRINT_LINK_ARGS) != 0 {
1139 println!("{}", &cmd);
1142 // May have not found libraries in the right formats.
1143 sess.abort_if_errors();
1145 // Invoke the system linker
1147 let prog = time(sess.time_passes(), "running linker", (), |()| cmd.output());
1150 if !prog.status.success() {
1151 sess.err(format!("linking with `{}` failed: {}",
1153 prog.status).as_slice());
1154 sess.note(format!("{}", &cmd).as_slice());
1155 let mut output = prog.error.clone();
1156 output.push_all(prog.output.as_slice());
1157 sess.note(str::from_utf8(output.as_slice()).unwrap()
1159 sess.abort_if_errors();
1163 sess.err(format!("could not exec the linker `{}`: {}",
1166 sess.abort_if_errors();
1171 // On OSX, debuggers need this utility to get run to do some munging of
1173 if (sess.targ_cfg.os == abi::OsMacos || sess.targ_cfg.os == abi::OsiOS)
1174 && (sess.opts.debuginfo != NoDebugInfo) {
1175 match Command::new("dsymutil").arg(out_filename).status() {
1178 sess.err(format!("failed to run dsymutil: {}", e).as_slice());
1179 sess.abort_if_errors();
1185 fn link_args(cmd: &mut Command,
1189 trans: &CrateTranslation,
1190 obj_filename: &Path,
1191 out_filename: &Path) {
1193 // The default library location, we need this to find the runtime.
1194 // The location of crates will be determined as needed.
1195 let lib_path = sess.target_filesearch().get_lib_path();
1196 cmd.arg("-L").arg(&lib_path);
1198 cmd.arg("-o").arg(out_filename).arg(obj_filename);
1200 // Stack growth requires statically linking a __morestack function. Note
1201 // that this is listed *before* all other libraries. Due to the usage of the
1202 // --as-needed flag below, the standard library may only be useful for its
1203 // rust_stack_exhausted function. In this case, we must ensure that the
1204 // libmorestack.a file appears *before* the standard library (so we put it
1205 // at the very front).
1207 // Most of the time this is sufficient, except for when LLVM gets super
1208 // clever. If, for example, we have a main function `fn main() {}`, LLVM
1209 // will optimize out calls to `__morestack` entirely because the function
1210 // doesn't need any stack at all!
1212 // To get around this snag, we specially tell the linker to always include
1213 // all contents of this library. This way we're guaranteed that the linker
1214 // will include the __morestack symbol 100% of the time, always resolving
1215 // references to it even if the object above didn't use it.
1216 match sess.targ_cfg.os {
1217 abi::OsMacos | abi::OsiOS => {
1218 let morestack = lib_path.join("libmorestack.a");
1220 let mut v = "-Wl,-force_load,".as_bytes().to_owned();
1221 v.push_all(morestack.as_vec());
1222 cmd.arg(v.as_slice());
1225 cmd.args(["-Wl,--whole-archive", "-lmorestack",
1226 "-Wl,--no-whole-archive"]);
1230 // When linking a dynamic library, we put the metadata into a section of the
1231 // executable. This metadata is in a separate object file from the main
1232 // object file, so we link that in here.
1234 cmd.arg(obj_filename.with_extension("metadata.o"));
1237 // We want to prevent the compiler from accidentally leaking in any system
1238 // libraries, so we explicitly ask gcc to not link to any libraries by
1239 // default. Note that this does not happen for windows because windows pulls
1240 // in some large number of libraries and I couldn't quite figure out which
1241 // subset we wanted.
1243 // FIXME(#11937) we should invoke the system linker directly
1244 if sess.targ_cfg.os != abi::OsWin32 {
1245 cmd.arg("-nodefaultlibs");
1248 // If we're building a dylib, we don't use --gc-sections because LLVM has
1249 // already done the best it can do, and we also don't want to eliminate the
1250 // metadata. If we're building an executable, however, --gc-sections drops
1251 // the size of hello world from 1.8MB to 597K, a 67% reduction.
1252 if !dylib && sess.targ_cfg.os != abi::OsMacos && sess.targ_cfg.os != abi::OsiOS {
1253 cmd.arg("-Wl,--gc-sections");
1256 if sess.targ_cfg.os == abi::OsLinux {
1257 // GNU-style linkers will use this to omit linking to libraries which
1258 // don't actually fulfill any relocations, but only for libraries which
1259 // follow this flag. Thus, use it before specifying libraries to link to.
1260 cmd.arg("-Wl,--as-needed");
1262 // GNU-style linkers support optimization with -O. GNU ld doesn't need a
1263 // numeric argument, but other linkers do.
1264 if sess.opts.optimize == config::Default ||
1265 sess.opts.optimize == config::Aggressive {
1268 } else if sess.targ_cfg.os == abi::OsMacos || sess.targ_cfg.os == abi::OsiOS {
1269 // The dead_strip option to the linker specifies that functions and data
1270 // unreachable by the entry point will be removed. This is quite useful
1271 // with Rust's compilation model of compiling libraries at a time into
1272 // one object file. For example, this brings hello world from 1.7MB to
1275 // Note that this is done for both executables and dynamic libraries. We
1276 // won't get much benefit from dylibs because LLVM will have already
1277 // stripped away as much as it could. This has not been seen to impact
1278 // link times negatively.
1279 cmd.arg("-Wl,-dead_strip");
1282 if sess.targ_cfg.os == abi::OsWin32 {
1283 // Make sure that we link to the dynamic libgcc, otherwise cross-module
1284 // DWARF stack unwinding will not work.
1285 // This behavior may be overridden by --link-args "-static-libgcc"
1286 cmd.arg("-shared-libgcc");
1288 // And here, we see obscure linker flags #45. On windows, it has been
1289 // found to be necessary to have this flag to compile liblibc.
1291 // First a bit of background. On Windows, the file format is not ELF,
1292 // but COFF (at least according to LLVM). COFF doesn't officially allow
1293 // for section names over 8 characters, apparently. Our metadata
1294 // section, ".note.rustc", you'll note is over 8 characters.
1296 // On more recent versions of gcc on mingw, apparently the section name
1297 // is *not* truncated, but rather stored elsewhere in a separate lookup
1298 // table. On older versions of gcc, they apparently always truncated the
1299 // section names (at least in some cases). Truncating the section name
1300 // actually creates "invalid" objects [1] [2], but only for some
1301 // introspection tools, not in terms of whether it can be loaded.
1303 // Long story short, passing this flag forces the linker to *not*
1304 // truncate section names (so we can find the metadata section after
1305 // it's compiled). The real kicker is that rust compiled just fine on
1306 // windows for quite a long time *without* this flag, so I have no idea
1307 // why it suddenly started failing for liblibc. Regardless, we
1308 // definitely don't want section name truncation, so we're keeping this
1309 // flag for windows.
1311 // [1] - https://sourceware.org/bugzilla/show_bug.cgi?id=13130
1312 // [2] - https://code.google.com/p/go/issues/detail?id=2139
1313 cmd.arg("-Wl,--enable-long-section-names");
1316 if sess.targ_cfg.os == abi::OsAndroid {
1317 // Many of the symbols defined in compiler-rt are also defined in libgcc.
1318 // Android linker doesn't like that by default.
1319 cmd.arg("-Wl,--allow-multiple-definition");
1322 // Take careful note of the ordering of the arguments we pass to the linker
1323 // here. Linkers will assume that things on the left depend on things to the
1324 // right. Things on the right cannot depend on things on the left. This is
1325 // all formally implemented in terms of resolving symbols (libs on the right
1326 // resolve unknown symbols of libs on the left, but not vice versa).
1328 // For this reason, we have organized the arguments we pass to the linker as
1331 // 1. The local object that LLVM just generated
1332 // 2. Upstream rust libraries
1333 // 3. Local native libraries
1334 // 4. Upstream native libraries
1336 // This is generally fairly natural, but some may expect 2 and 3 to be
1337 // swapped. The reason that all native libraries are put last is that it's
1338 // not recommended for a native library to depend on a symbol from a rust
1339 // crate. If this is the case then a staticlib crate is recommended, solving
1342 // Additionally, it is occasionally the case that upstream rust libraries
1343 // depend on a local native library. In the case of libraries such as
1344 // lua/glfw/etc the name of the library isn't the same across all platforms,
1345 // so only the consumer crate of a library knows the actual name. This means
1346 // that downstream crates will provide the #[link] attribute which upstream
1347 // crates will depend on. Hence local native libraries are after out
1348 // upstream rust crates.
1350 // In theory this means that a symbol in an upstream native library will be
1351 // shadowed by a local native library when it wouldn't have been before, but
1352 // this kind of behavior is pretty platform specific and generally not
1353 // recommended anyway, so I don't think we're shooting ourself in the foot
1355 add_upstream_rust_crates(cmd, sess, dylib, tmpdir, trans);
1356 add_local_native_libraries(cmd, sess);
1357 add_upstream_native_libraries(cmd, sess);
1359 // # Telling the linker what we're doing
1362 // On mac we need to tell the linker to let this library be rpathed
1363 if sess.targ_cfg.os == abi::OsMacos {
1364 cmd.args(["-dynamiclib", "-Wl,-dylib"]);
1366 if sess.opts.cg.rpath {
1367 let mut v = Vec::from_slice("-Wl,-install_name,@rpath/".as_bytes());
1368 v.push_all(out_filename.filename().unwrap());
1369 cmd.arg(v.as_slice());
1376 if sess.targ_cfg.os == abi::OsFreebsd {
1377 cmd.args(["-L/usr/local/lib",
1378 "-L/usr/local/lib/gcc46",
1379 "-L/usr/local/lib/gcc44"]);
1382 // FIXME (#2397): At some point we want to rpath our guesses as to
1383 // where extern libraries might live, based on the
1384 // addl_lib_search_paths
1385 if sess.opts.cg.rpath {
1386 cmd.args(rpath::get_rpath_flags(sess, out_filename).as_slice());
1389 // compiler-rt contains implementations of low-level LLVM helpers. This is
1390 // used to resolve symbols from the object file we just created, as well as
1391 // any system static libraries that may be expecting gcc instead. Most
1392 // symbols in libgcc also appear in compiler-rt.
1394 // This is the end of the command line, so this library is used to resolve
1395 // *all* undefined symbols in all other libraries, and this is intentional.
1396 cmd.arg("-lcompiler-rt");
1398 // Finally add all the linker arguments provided on the command line along
1399 // with any #[link_args] attributes found inside the crate
1400 cmd.args(sess.opts.cg.link_args.as_slice());
1401 for arg in sess.cstore.get_used_link_args().borrow().iter() {
1402 cmd.arg(arg.as_slice());
1406 // # Native library linking
1408 // User-supplied library search paths (-L on the command line). These are
1409 // the same paths used to find Rust crates, so some of them may have been
1410 // added already by the previous crate linking code. This only allows them
1411 // to be found at compile time so it is still entirely up to outside
1412 // forces to make sure that library can be found at runtime.
1414 // Also note that the native libraries linked here are only the ones located
1415 // in the current crate. Upstream crates with native library dependencies
1416 // may have their native library pulled in above.
1417 fn add_local_native_libraries(cmd: &mut Command, sess: &Session) {
1418 for path in sess.opts.addl_lib_search_paths.borrow().iter() {
1419 cmd.arg("-L").arg(path);
1422 let rustpath = filesearch::rust_path();
1423 for path in rustpath.iter() {
1424 cmd.arg("-L").arg(path);
1427 // Some platforms take hints about whether a library is static or dynamic.
1428 // For those that support this, we ensure we pass the option if the library
1429 // was flagged "static" (most defaults are dynamic) to ensure that if
1430 // libfoo.a and libfoo.so both exist that the right one is chosen.
1431 let takes_hints = sess.targ_cfg.os != abi::OsMacos && sess.targ_cfg.os != abi::OsiOS;
1433 for &(ref l, kind) in sess.cstore.get_used_libraries().borrow().iter() {
1435 cstore::NativeUnknown | cstore::NativeStatic => {
1437 if kind == cstore::NativeStatic {
1438 cmd.arg("-Wl,-Bstatic");
1440 cmd.arg("-Wl,-Bdynamic");
1443 cmd.arg(format!("-l{}", *l));
1445 cstore::NativeFramework => {
1446 cmd.arg("-framework");
1447 cmd.arg(l.as_slice());
1452 cmd.arg("-Wl,-Bdynamic");
1456 // # Rust Crate linking
1458 // Rust crates are not considered at all when creating an rlib output. All
1459 // dependencies will be linked when producing the final output (instead of
1460 // the intermediate rlib version)
1461 fn add_upstream_rust_crates(cmd: &mut Command, sess: &Session,
1462 dylib: bool, tmpdir: &Path,
1463 trans: &CrateTranslation) {
1464 // All of the heavy lifting has previously been accomplished by the
1465 // dependency_format module of the compiler. This is just crawling the
1466 // output of that module, adding crates as necessary.
1468 // Linking to a rlib involves just passing it to the linker (the linker
1469 // will slurp up the object files inside), and linking to a dynamic library
1470 // involves just passing the right -l flag.
1472 let data = if dylib {
1473 trans.crate_formats.get(&config::CrateTypeDylib)
1475 trans.crate_formats.get(&config::CrateTypeExecutable)
1478 // Invoke get_used_crates to ensure that we get a topological sorting of
1480 let deps = sess.cstore.get_used_crates(cstore::RequireDynamic);
1482 for &(cnum, _) in deps.iter() {
1483 // We may not pass all crates through to the linker. Some crates may
1484 // appear statically in an existing dylib, meaning we'll pick up all the
1485 // symbols from the dylib.
1486 let kind = match *data.get(cnum as uint - 1) {
1490 let src = sess.cstore.get_used_crate_source(cnum).unwrap();
1492 cstore::RequireDynamic => {
1493 add_dynamic_crate(cmd, sess, src.dylib.unwrap())
1495 cstore::RequireStatic => {
1496 add_static_crate(cmd, sess, tmpdir, cnum, src.rlib.unwrap())
1502 // Converts a library file-stem into a cc -l argument
1503 fn unlib<'a>(config: &config::Config, stem: &'a [u8]) -> &'a [u8] {
1504 if stem.starts_with("lib".as_bytes()) && config.os != abi::OsWin32 {
1511 // Adds the static "rlib" versions of all crates to the command line.
1512 fn add_static_crate(cmd: &mut Command, sess: &Session, tmpdir: &Path,
1513 cnum: ast::CrateNum, cratepath: Path) {
1514 // When performing LTO on an executable output, all of the
1515 // bytecode from the upstream libraries has already been
1516 // included in our object file output. We need to modify all of
1517 // the upstream archives to remove their corresponding object
1518 // file to make sure we don't pull the same code in twice.
1520 // We must continue to link to the upstream archives to be sure
1521 // to pull in native static dependencies. As the final caveat,
1522 // on linux it is apparently illegal to link to a blank archive,
1523 // so if an archive no longer has any object files in it after
1524 // we remove `lib.o`, then don't link against it at all.
1526 // If we're not doing LTO, then our job is simply to just link
1527 // against the archive.
1529 let name = sess.cstore.get_crate_data(cnum).name.clone();
1530 time(sess.time_passes(),
1531 format!("altering {}.rlib", name).as_slice(),
1533 let dst = tmpdir.join(cratepath.filename().unwrap());
1534 match fs::copy(&cratepath, &dst) {
1537 sess.err(format!("failed to copy {} to {}: {}",
1538 cratepath.display(),
1541 sess.abort_if_errors();
1544 let mut archive = Archive::open(sess, dst.clone());
1545 archive.remove_file(format!("{}.o", name).as_slice());
1546 let files = archive.files();
1547 if files.iter().any(|s| s.as_slice().ends_with(".o")) {
1556 // Same thing as above, but for dynamic crates instead of static crates.
1557 fn add_dynamic_crate(cmd: &mut Command, sess: &Session, cratepath: Path) {
1558 // If we're performing LTO, then it should have been previously required
1559 // that all upstream rust dependencies were available in an rlib format.
1560 assert!(!sess.lto());
1562 // Just need to tell the linker about where the library lives and
1564 let dir = cratepath.dirname();
1565 if !dir.is_empty() { cmd.arg("-L").arg(dir); }
1567 let mut v = Vec::from_slice("-l".as_bytes());
1568 v.push_all(unlib(&sess.targ_cfg, cratepath.filestem().unwrap()));
1569 cmd.arg(v.as_slice());
1573 // Link in all of our upstream crates' native dependencies. Remember that
1574 // all of these upstream native dependencies are all non-static
1575 // dependencies. We've got two cases then:
1577 // 1. The upstream crate is an rlib. In this case we *must* link in the
1578 // native dependency because the rlib is just an archive.
1580 // 2. The upstream crate is a dylib. In order to use the dylib, we have to
1581 // have the dependency present on the system somewhere. Thus, we don't
1582 // gain a whole lot from not linking in the dynamic dependency to this
1585 // The use case for this is a little subtle. In theory the native
1586 // dependencies of a crate are purely an implementation detail of the crate
1587 // itself, but the problem arises with generic and inlined functions. If a
1588 // generic function calls a native function, then the generic function must
1589 // be instantiated in the target crate, meaning that the native symbol must
1590 // also be resolved in the target crate.
1591 fn add_upstream_native_libraries(cmd: &mut Command, sess: &Session) {
1592 // Be sure to use a topological sorting of crates because there may be
1593 // interdependencies between native libraries. When passing -nodefaultlibs,
1594 // for example, almost all native libraries depend on libc, so we have to
1595 // make sure that's all the way at the right (liblibc is near the base of
1596 // the dependency chain).
1598 // This passes RequireStatic, but the actual requirement doesn't matter,
1599 // we're just getting an ordering of crate numbers, we're not worried about
1601 let crates = sess.cstore.get_used_crates(cstore::RequireStatic);
1602 for (cnum, _) in crates.move_iter() {
1603 let libs = csearch::get_native_libraries(&sess.cstore, cnum);
1604 for &(kind, ref lib) in libs.iter() {
1606 cstore::NativeUnknown => {
1607 cmd.arg(format!("-l{}", *lib));
1609 cstore::NativeFramework => {
1610 cmd.arg("-framework");
1611 cmd.arg(lib.as_slice());
1613 cstore::NativeStatic => {
1614 sess.bug("statics shouldn't be propagated");