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};
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};
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};
44 use syntax::attr::AttrMetaMethods;
45 use syntax::crateid::CrateId;
46 use syntax::parse::token;
48 #[deriving(Clone, Eq, Ord, TotalOrd, TotalEq)]
52 OutputTypeLlvmAssembly,
57 pub fn llvm_err(sess: &Session, msg: String) -> ! {
59 let cstr = llvm::LLVMRustGetLastError();
60 if cstr == ptr::null() {
61 sess.fatal(msg.as_slice());
63 let err = CString::new(cstr, true);
64 let err = str::from_utf8_lossy(err.as_bytes());
65 sess.fatal(format!("{}: {}",
67 err.as_slice()).as_slice());
72 pub fn WriteOutputFile(
74 target: lib::llvm::TargetMachineRef,
75 pm: lib::llvm::PassManagerRef,
78 file_type: lib::llvm::FileType) {
80 output.with_c_str(|output| {
81 let result = llvm::LLVMRustWriteOutputFile(
82 target, pm, m, output, file_type);
84 llvm_err(sess, "could not write output".to_string());
93 use back::link::{WriteOutputFile, OutputType};
94 use back::link::{OutputTypeAssembly, OutputTypeBitcode};
95 use back::link::{OutputTypeExe, OutputTypeLlvmAssembly};
96 use back::link::{OutputTypeObject};
97 use driver::driver::{CrateTranslation, OutputFilenames};
98 use driver::config::NoDebugInfo;
99 use driver::session::Session;
102 use lib::llvm::{ModuleRef, TargetMachineRef, PassManagerRef};
104 use util::common::time;
107 use std::c_str::ToCStr;
108 use std::io::{Command};
109 use libc::{c_uint, c_int};
112 // On android, we by default compile for armv7 processors. This enables
113 // things like double word CAS instructions (rather than emulating them)
114 // which are *far* more efficient. This is obviously undesirable in some
115 // cases, so if any sort of target feature is specified we don't append v7
116 // to the feature list.
117 fn target_feature<'a>(sess: &'a Session) -> &'a str {
118 match sess.targ_cfg.os {
120 if "" == sess.opts.cg.target_feature.as_slice() {
123 sess.opts.cg.target_feature.as_slice()
126 _ => sess.opts.cg.target_feature.as_slice()
130 pub fn run_passes(sess: &Session,
131 trans: &CrateTranslation,
132 output_types: &[OutputType],
133 output: &OutputFilenames) {
134 let llmod = trans.module;
135 let llcx = trans.context;
137 configure_llvm(sess);
139 if sess.opts.cg.save_temps {
140 output.with_extension("no-opt.bc").with_c_str(|buf| {
141 llvm::LLVMWriteBitcodeToFile(llmod, buf);
145 let opt_level = match sess.opts.optimize {
146 config::No => lib::llvm::CodeGenLevelNone,
147 config::Less => lib::llvm::CodeGenLevelLess,
148 config::Default => lib::llvm::CodeGenLevelDefault,
149 config::Aggressive => lib::llvm::CodeGenLevelAggressive,
151 let use_softfp = sess.opts.cg.soft_float;
153 // FIXME: #11906: Omitting frame pointers breaks retrieving the value of a parameter.
154 // FIXME: #11954: mac64 unwinding may not work with fp elim
155 let no_fp_elim = (sess.opts.debuginfo != NoDebugInfo) ||
156 (sess.targ_cfg.os == abi::OsMacos &&
157 sess.targ_cfg.arch == abi::X86_64);
159 // OSX has -dead_strip, which doesn't rely on ffunction_sections
160 // FIXME(#13846) this should be enabled for windows
161 let ffunction_sections = sess.targ_cfg.os != abi::OsMacos &&
162 sess.targ_cfg.os != abi::OsWin32;
163 let fdata_sections = ffunction_sections;
165 let reloc_model = match sess.opts.cg.relocation_model.as_slice() {
166 "pic" => lib::llvm::RelocPIC,
167 "static" => lib::llvm::RelocStatic,
168 "default" => lib::llvm::RelocDefault,
169 "dynamic-no-pic" => lib::llvm::RelocDynamicNoPic,
171 sess.err(format!("{} is not a valid relocation mode",
174 .relocation_model).as_slice());
175 sess.abort_if_errors();
180 let tm = sess.targ_cfg
185 sess.opts.cg.target_cpu.as_slice().with_c_str(|cpu| {
186 target_feature(sess).with_c_str(|features| {
187 llvm::LLVMRustCreateTargetMachine(
189 lib::llvm::CodeModelDefault,
192 true /* EnableSegstk */,
202 // Create the two optimizing pass managers. These mirror what clang
203 // does, and are by populated by LLVM's default PassManagerBuilder.
204 // Each manager has a different set of passes, but they also share
205 // some common passes.
206 let fpm = llvm::LLVMCreateFunctionPassManagerForModule(llmod);
207 let mpm = llvm::LLVMCreatePassManager();
209 // If we're verifying or linting, add them to the function pass
211 let addpass = |pass: &str| {
212 pass.as_slice().with_c_str(|s| llvm::LLVMRustAddPass(fpm, s))
214 if !sess.no_verify() { assert!(addpass("verify")); }
216 if !sess.opts.cg.no_prepopulate_passes {
217 llvm::LLVMRustAddAnalysisPasses(tm, fpm, llmod);
218 llvm::LLVMRustAddAnalysisPasses(tm, mpm, llmod);
219 populate_llvm_passes(fpm, mpm, llmod, opt_level,
223 for pass in sess.opts.cg.passes.iter() {
224 pass.as_slice().with_c_str(|s| {
225 if !llvm::LLVMRustAddPass(mpm, s) {
226 sess.warn(format!("unknown pass {}, ignoring",
232 // Finally, run the actual optimization passes
233 time(sess.time_passes(), "llvm function passes", (), |()|
234 llvm::LLVMRustRunFunctionPassManager(fpm, llmod));
235 time(sess.time_passes(), "llvm module passes", (), |()|
236 llvm::LLVMRunPassManager(mpm, llmod));
238 // Deallocate managers that we're now done with
239 llvm::LLVMDisposePassManager(fpm);
240 llvm::LLVMDisposePassManager(mpm);
242 // Emit the bytecode if we're either saving our temporaries or
243 // emitting an rlib. Whenever an rlib is created, the bytecode is
244 // inserted into the archive in order to allow LTO against it.
245 if sess.opts.cg.save_temps ||
246 (sess.crate_types.borrow().contains(&config::CrateTypeRlib) &&
247 sess.opts.output_types.contains(&OutputTypeExe)) {
248 output.temp_path(OutputTypeBitcode).with_c_str(|buf| {
249 llvm::LLVMWriteBitcodeToFile(llmod, buf);
254 time(sess.time_passes(), "all lto passes", (), |()|
255 lto::run(sess, llmod, tm, trans.reachable.as_slice()));
257 if sess.opts.cg.save_temps {
258 output.with_extension("lto.bc").with_c_str(|buf| {
259 llvm::LLVMWriteBitcodeToFile(llmod, buf);
264 // A codegen-specific pass manager is used to generate object
265 // files for an LLVM module.
267 // Apparently each of these pass managers is a one-shot kind of
268 // thing, so we create a new one for each type of output. The
269 // pass manager passed to the closure should be ensured to not
270 // escape the closure itself, and the manager should only be
272 fn with_codegen(tm: TargetMachineRef, llmod: ModuleRef,
273 no_builtins: bool, f: |PassManagerRef|) {
275 let cpm = llvm::LLVMCreatePassManager();
276 llvm::LLVMRustAddAnalysisPasses(tm, cpm, llmod);
277 llvm::LLVMRustAddLibraryInfo(cpm, llmod, no_builtins);
279 llvm::LLVMDisposePassManager(cpm);
283 let mut object_file = None;
284 let mut needs_metadata = false;
285 for output_type in output_types.iter() {
286 let path = output.path(*output_type);
288 OutputTypeBitcode => {
289 path.with_c_str(|buf| {
290 llvm::LLVMWriteBitcodeToFile(llmod, buf);
293 OutputTypeLlvmAssembly => {
294 path.with_c_str(|output| {
295 with_codegen(tm, llmod, trans.no_builtins, |cpm| {
296 llvm::LLVMRustPrintModule(cpm, llmod, output);
300 OutputTypeAssembly => {
301 // If we're not using the LLVM assembler, this function
302 // could be invoked specially with output_type_assembly,
303 // so in this case we still want the metadata object
305 let ty = OutputTypeAssembly;
306 let path = if sess.opts.output_types.contains(&ty) {
309 needs_metadata = true;
310 output.temp_path(OutputTypeAssembly)
312 with_codegen(tm, llmod, trans.no_builtins, |cpm| {
313 WriteOutputFile(sess, tm, cpm, llmod, &path,
314 lib::llvm::AssemblyFile);
317 OutputTypeObject => {
318 object_file = Some(path);
321 object_file = Some(output.temp_path(OutputTypeObject));
322 needs_metadata = true;
327 time(sess.time_passes(), "codegen passes", (), |()| {
330 with_codegen(tm, llmod, trans.no_builtins, |cpm| {
331 WriteOutputFile(sess, tm, cpm, llmod, path,
332 lib::llvm::ObjectFile);
338 with_codegen(tm, trans.metadata_module,
339 trans.no_builtins, |cpm| {
340 let out = output.temp_path(OutputTypeObject)
341 .with_extension("metadata.o");
342 WriteOutputFile(sess, tm, cpm,
343 trans.metadata_module, &out,
344 lib::llvm::ObjectFile);
349 llvm::LLVMRustDisposeTargetMachine(tm);
350 llvm::LLVMDisposeModule(trans.metadata_module);
351 llvm::LLVMDisposeModule(llmod);
352 llvm::LLVMContextDispose(llcx);
353 if sess.time_llvm_passes() { llvm::LLVMRustPrintPassTimings(); }
357 pub fn run_assembler(sess: &Session, outputs: &OutputFilenames) {
358 let pname = super::get_cc_prog(sess);
359 let mut cmd = Command::new(pname.as_slice());
361 cmd.arg("-c").arg("-o").arg(outputs.path(OutputTypeObject))
362 .arg(outputs.temp_path(OutputTypeAssembly));
367 if !prog.status.success() {
368 sess.err(format!("linking with `{}` failed: {}",
370 prog.status).as_slice());
371 sess.note(format!("{}", &cmd).as_slice());
372 let mut note = prog.error.clone();
373 note.push_all(prog.output.as_slice());
374 sess.note(str::from_utf8(note.as_slice()).unwrap()
376 sess.abort_if_errors();
380 sess.err(format!("could not exec the linker `{}`: {}",
383 sess.abort_if_errors();
388 unsafe fn configure_llvm(sess: &Session) {
389 use sync::one::{Once, ONCE_INIT};
390 static mut INIT: Once = ONCE_INIT;
392 // Copy what clang does by turning on loop vectorization at O2 and
393 // slp vectorization at O3
394 let vectorize_loop = !sess.opts.cg.no_vectorize_loops &&
395 (sess.opts.optimize == config::Default ||
396 sess.opts.optimize == config::Aggressive);
397 let vectorize_slp = !sess.opts.cg.no_vectorize_slp &&
398 sess.opts.optimize == config::Aggressive;
400 let mut llvm_c_strs = Vec::new();
401 let mut llvm_args = Vec::new();
403 let add = |arg: &str| {
404 let s = arg.to_c_str();
405 llvm_args.push(s.with_ref(|p| p));
408 add("rustc"); // fake program name
409 if vectorize_loop { add("-vectorize-loops"); }
410 if vectorize_slp { add("-vectorize-slp"); }
411 if sess.time_llvm_passes() { add("-time-passes"); }
412 if sess.print_llvm_passes() { add("-debug-pass=Structure"); }
414 for arg in sess.opts.cg.llvm_args.iter() {
415 add((*arg).as_slice());
420 llvm::LLVMInitializePasses();
422 // Only initialize the platforms supported by Rust here, because
423 // using --llvm-root will have multiple platforms that rustllvm
424 // doesn't actually link to and it's pointless to put target info
425 // into the registry that Rust cannot generate machine code for.
426 llvm::LLVMInitializeX86TargetInfo();
427 llvm::LLVMInitializeX86Target();
428 llvm::LLVMInitializeX86TargetMC();
429 llvm::LLVMInitializeX86AsmPrinter();
430 llvm::LLVMInitializeX86AsmParser();
432 llvm::LLVMInitializeARMTargetInfo();
433 llvm::LLVMInitializeARMTarget();
434 llvm::LLVMInitializeARMTargetMC();
435 llvm::LLVMInitializeARMAsmPrinter();
436 llvm::LLVMInitializeARMAsmParser();
438 llvm::LLVMInitializeMipsTargetInfo();
439 llvm::LLVMInitializeMipsTarget();
440 llvm::LLVMInitializeMipsTargetMC();
441 llvm::LLVMInitializeMipsAsmPrinter();
442 llvm::LLVMInitializeMipsAsmParser();
444 llvm::LLVMRustSetLLVMOptions(llvm_args.len() as c_int,
449 unsafe fn populate_llvm_passes(fpm: lib::llvm::PassManagerRef,
450 mpm: lib::llvm::PassManagerRef,
452 opt: lib::llvm::CodeGenOptLevel,
454 // Create the PassManagerBuilder for LLVM. We configure it with
455 // reasonable defaults and prepare it to actually populate the pass
457 let builder = llvm::LLVMPassManagerBuilderCreate();
459 lib::llvm::CodeGenLevelNone => {
460 // Don't add lifetime intrinsics at O0
461 llvm::LLVMRustAddAlwaysInlinePass(builder, false);
463 lib::llvm::CodeGenLevelLess => {
464 llvm::LLVMRustAddAlwaysInlinePass(builder, true);
466 // numeric values copied from clang
467 lib::llvm::CodeGenLevelDefault => {
468 llvm::LLVMPassManagerBuilderUseInlinerWithThreshold(builder,
471 lib::llvm::CodeGenLevelAggressive => {
472 llvm::LLVMPassManagerBuilderUseInlinerWithThreshold(builder,
476 llvm::LLVMPassManagerBuilderSetOptLevel(builder, opt as c_uint);
477 llvm::LLVMRustAddBuilderLibraryInfo(builder, llmod, no_builtins);
479 // Use the builder to populate the function/module pass managers.
480 llvm::LLVMPassManagerBuilderPopulateFunctionPassManager(builder, fpm);
481 llvm::LLVMPassManagerBuilderPopulateModulePassManager(builder, mpm);
482 llvm::LLVMPassManagerBuilderDispose(builder);
488 * Name mangling and its relationship to metadata. This is complex. Read
491 * The semantic model of Rust linkage is, broadly, that "there's no global
492 * namespace" between crates. Our aim is to preserve the illusion of this
493 * model despite the fact that it's not *quite* possible to implement on
494 * modern linkers. We initially didn't use system linkers at all, but have
495 * been convinced of their utility.
497 * There are a few issues to handle:
499 * - Linkers operate on a flat namespace, so we have to flatten names.
500 * We do this using the C++ namespace-mangling technique. Foo::bar
503 * - Symbols with the same name but different types need to get different
504 * linkage-names. We do this by hashing a string-encoding of the type into
505 * a fixed-size (currently 16-byte hex) cryptographic hash function (CHF:
506 * we use SHA256) to "prevent collisions". This is not airtight but 16 hex
507 * digits on uniform probability means you're going to need 2**32 same-name
508 * symbols in the same process before you're even hitting birthday-paradox
509 * collision probability.
511 * - Symbols in different crates but with same names "within" the crate need
512 * to get different linkage-names.
514 * - The hash shown in the filename needs to be predictable and stable for
515 * build tooling integration. It also needs to be using a hash function
516 * which is easy to use from Python, make, etc.
518 * So here is what we do:
520 * - Consider the package id; every crate has one (specified with crate_id
521 * attribute). If a package id isn't provided explicitly, we infer a
522 * versionless one from the output name. The version will end up being 0.0
523 * in this case. CNAME and CVERS are taken from this package id. For
524 * example, github.com/mozilla/CNAME#CVERS.
526 * - Define CMH as SHA256(crateid).
528 * - Define CMH8 as the first 8 characters of CMH.
530 * - Compile our crate to lib CNAME-CMH8-CVERS.so
532 * - Define STH(sym) as SHA256(CMH, type_str(sym))
534 * - Suffix a mangled sym with ::STH@CVERS, so that it is unique in the
535 * name, non-name metadata, and type sense, and versioned in the way
536 * system linkers understand.
539 // FIXME (#9639): This needs to handle non-utf8 `out_filestem` values
540 pub fn find_crate_id(attrs: &[ast::Attribute], out_filestem: &str) -> CrateId {
541 match attr::find_crateid(attrs) {
542 None => from_str(out_filestem).unwrap_or_else(|| {
543 let mut s = out_filestem.chars().filter(|c| c.is_XID_continue());
544 from_str(s.collect::<String>().as_slice())
545 .or(from_str("rust-out")).unwrap()
551 pub fn crate_id_hash(crate_id: &CrateId) -> String {
552 // This calculates CMH as defined above. Note that we don't use the path of
553 // the crate id in the hash because lookups are only done by (name/vers),
555 let mut s = Sha256::new();
556 s.input_str(crate_id.short_name_with_version().as_slice());
557 truncated_hash_result(&mut s).as_slice().slice_to(8).to_string()
560 // FIXME (#9639): This needs to handle non-utf8 `out_filestem` values
561 pub fn build_link_meta(krate: &ast::Crate, out_filestem: &str) -> LinkMeta {
563 crateid: find_crate_id(krate.attrs.as_slice(), out_filestem),
564 crate_hash: Svh::calculate(krate),
570 fn truncated_hash_result(symbol_hasher: &mut Sha256) -> String {
571 let output = symbol_hasher.result_bytes();
572 // 64 bits should be enough to avoid collisions.
573 output.slice_to(8).to_hex().to_string()
577 // This calculates STH for a symbol, as defined above
578 fn symbol_hash(tcx: &ty::ctxt,
579 symbol_hasher: &mut Sha256,
581 link_meta: &LinkMeta)
583 // NB: do *not* use abbrevs here as we want the symbol names
584 // to be independent of one another in the crate.
586 symbol_hasher.reset();
587 symbol_hasher.input_str(link_meta.crateid.name.as_slice());
588 symbol_hasher.input_str("-");
589 symbol_hasher.input_str(link_meta.crate_hash.as_str());
590 symbol_hasher.input_str("-");
591 symbol_hasher.input_str(encoder::encoded_ty(tcx, t).as_slice());
592 // Prefix with 'h' so that it never blends into adjacent digits
593 let mut hash = String::from_str("h");
594 hash.push_str(truncated_hash_result(symbol_hasher).as_slice());
598 fn get_symbol_hash(ccx: &CrateContext, t: ty::t) -> String {
599 match ccx.type_hashcodes.borrow().find(&t) {
600 Some(h) => return h.to_string(),
604 let mut symbol_hasher = ccx.symbol_hasher.borrow_mut();
605 let hash = symbol_hash(ccx.tcx(), &mut *symbol_hasher, t, &ccx.link_meta);
606 ccx.type_hashcodes.borrow_mut().insert(t, hash.clone());
611 // Name sanitation. LLVM will happily accept identifiers with weird names, but
613 // gas accepts the following characters in symbols: a-z, A-Z, 0-9, ., _, $
614 pub fn sanitize(s: &str) -> String {
615 let mut result = String::new();
618 // Escape these with $ sequences
619 '@' => result.push_str("$SP$"),
620 '~' => result.push_str("$UP$"),
621 '*' => result.push_str("$RP$"),
622 '&' => result.push_str("$BP$"),
623 '<' => result.push_str("$LT$"),
624 '>' => result.push_str("$GT$"),
625 '(' => result.push_str("$LP$"),
626 ')' => result.push_str("$RP$"),
627 ',' => result.push_str("$C$"),
629 // '.' doesn't occur in types and functions, so reuse it
631 '-' | ':' => result.push_char('.'),
633 // These are legal symbols
637 | '_' | '.' | '$' => result.push_char(c),
640 let mut tstr = String::new();
641 char::escape_unicode(c, |c| tstr.push_char(c));
642 result.push_char('$');
643 result.push_str(tstr.as_slice().slice_from(1));
648 // Underscore-qualify anything that didn't start as an ident.
649 if result.len() > 0u &&
650 result.as_slice()[0] != '_' as u8 &&
651 ! char::is_XID_start(result.as_slice()[0] as char) {
652 return format!("_{}", result.as_slice()).to_string();
658 pub fn mangle<PI: Iterator<PathElem>>(mut path: PI,
660 vers: Option<&str>) -> String {
661 // Follow C++ namespace-mangling style, see
662 // http://en.wikipedia.org/wiki/Name_mangling for more info.
664 // It turns out that on OSX you can actually have arbitrary symbols in
665 // function names (at least when given to LLVM), but this is not possible
666 // when using unix's linker. Perhaps one day when we just use a linker from LLVM
667 // we won't need to do this name mangling. The problem with name mangling is
668 // that it seriously limits the available characters. For example we can't
669 // have things like &T or ~[T] in symbol names when one would theoretically
670 // want them for things like impls of traits on that type.
672 // To be able to work on all platforms and get *some* reasonable output, we
673 // use C++ name-mangling.
675 let mut n = String::from_str("_ZN"); // _Z == Begin name-sequence, N == nested
677 fn push(n: &mut String, s: &str) {
678 let sani = sanitize(s);
679 n.push_str(format!("{}{}", sani.len(), sani).as_slice());
682 // First, connect each component with <len, name> pairs.
684 push(&mut n, token::get_name(e.name()).get().as_slice())
688 Some(s) => push(&mut n, s),
692 Some(s) => push(&mut n, s),
696 n.push_char('E'); // End name-sequence.
700 pub fn exported_name(path: PathElems, hash: &str, vers: &str) -> String {
701 // The version will get mangled to have a leading '_', but it makes more
702 // sense to lead with a 'v' b/c this is a version...
703 let vers = if vers.len() > 0 && !char::is_XID_start(vers.char_at(0)) {
709 mangle(path, Some(hash), Some(vers.as_slice()))
712 pub fn mangle_exported_name(ccx: &CrateContext, path: PathElems,
713 t: ty::t, id: ast::NodeId) -> String {
714 let mut hash = get_symbol_hash(ccx, t);
716 // Paths can be completely identical for different nodes,
717 // e.g. `fn foo() { { fn a() {} } { fn a() {} } }`, so we
718 // generate unique characters from the node id. For now
719 // hopefully 3 characters is enough to avoid collisions.
720 static EXTRA_CHARS: &'static str =
721 "abcdefghijklmnopqrstuvwxyz\
722 ABCDEFGHIJKLMNOPQRSTUVWXYZ\
725 let extra1 = id % EXTRA_CHARS.len();
726 let id = id / EXTRA_CHARS.len();
727 let extra2 = id % EXTRA_CHARS.len();
728 let id = id / EXTRA_CHARS.len();
729 let extra3 = id % EXTRA_CHARS.len();
730 hash.push_char(EXTRA_CHARS[extra1] as char);
731 hash.push_char(EXTRA_CHARS[extra2] as char);
732 hash.push_char(EXTRA_CHARS[extra3] as char);
736 ccx.link_meta.crateid.version_or_default())
739 pub fn mangle_internal_name_by_type_and_seq(ccx: &CrateContext,
741 name: &str) -> String {
742 let s = ppaux::ty_to_str(ccx.tcx(), t);
743 let path = [PathName(token::intern(s.as_slice())),
745 let hash = get_symbol_hash(ccx, t);
746 mangle(ast_map::Values(path.iter()), Some(hash.as_slice()), None)
749 pub fn mangle_internal_name_by_path_and_seq(path: PathElems, flav: &str) -> String {
750 mangle(path.chain(Some(gensym_name(flav)).move_iter()), None, None)
753 pub fn output_lib_filename(id: &CrateId) -> String {
754 format_strbuf!("{}-{}-{}",
757 id.version_or_default())
760 pub fn get_cc_prog(sess: &Session) -> String {
761 match sess.opts.cg.linker {
762 Some(ref linker) => return linker.to_string(),
766 // In the future, FreeBSD will use clang as default compiler.
767 // It would be flexible to use cc (system's default C compiler)
768 // instead of hard-coded gcc.
769 // For win32, there is no cc command, so we add a condition to make it use gcc.
770 match sess.targ_cfg.os {
771 abi::OsWin32 => "gcc",
776 pub fn get_ar_prog(sess: &Session) -> String {
777 match sess.opts.cg.ar {
778 Some(ref ar) => (*ar).clone(),
779 None => "ar".to_string()
783 fn remove(sess: &Session, path: &Path) {
784 match fs::unlink(path) {
787 sess.err(format!("failed to remove {}: {}",
794 /// Perform the linkage portion of the compilation phase. This will generate all
795 /// of the requested outputs for this compilation session.
796 pub fn link_binary(sess: &Session,
797 trans: &CrateTranslation,
798 outputs: &OutputFilenames,
799 id: &CrateId) -> Vec<Path> {
800 let mut out_filenames = Vec::new();
801 for &crate_type in sess.crate_types.borrow().iter() {
802 let out_file = link_binary_output(sess, trans, crate_type, outputs, id);
803 out_filenames.push(out_file);
806 // Remove the temporary object file and metadata if we aren't saving temps
807 if !sess.opts.cg.save_temps {
808 let obj_filename = outputs.temp_path(OutputTypeObject);
809 if !sess.opts.output_types.contains(&OutputTypeObject) {
810 remove(sess, &obj_filename);
812 remove(sess, &obj_filename.with_extension("metadata.o"));
818 fn is_writeable(p: &Path) -> bool {
821 Ok(m) => m.perm & io::UserWrite == io::UserWrite
825 pub fn filename_for_input(sess: &Session, crate_type: config::CrateType,
826 id: &CrateId, out_filename: &Path) -> Path {
827 let libname = output_lib_filename(id);
829 config::CrateTypeRlib => {
830 out_filename.with_filename(format_strbuf!("lib{}.rlib", libname))
832 config::CrateTypeDylib => {
833 let (prefix, suffix) = match sess.targ_cfg.os {
834 abi::OsWin32 => (loader::WIN32_DLL_PREFIX, loader::WIN32_DLL_SUFFIX),
835 abi::OsMacos => (loader::MACOS_DLL_PREFIX, loader::MACOS_DLL_SUFFIX),
836 abi::OsLinux => (loader::LINUX_DLL_PREFIX, loader::LINUX_DLL_SUFFIX),
837 abi::OsAndroid => (loader::ANDROID_DLL_PREFIX, loader::ANDROID_DLL_SUFFIX),
838 abi::OsFreebsd => (loader::FREEBSD_DLL_PREFIX, loader::FREEBSD_DLL_SUFFIX),
840 out_filename.with_filename(format_strbuf!("{}{}{}",
845 config::CrateTypeStaticlib => {
846 out_filename.with_filename(format_strbuf!("lib{}.a", libname))
848 config::CrateTypeExecutable => out_filename.clone(),
852 fn link_binary_output(sess: &Session,
853 trans: &CrateTranslation,
854 crate_type: config::CrateType,
855 outputs: &OutputFilenames,
856 id: &CrateId) -> Path {
857 let obj_filename = outputs.temp_path(OutputTypeObject);
858 let out_filename = match outputs.single_output_file {
859 Some(ref file) => file.clone(),
861 let out_filename = outputs.path(OutputTypeExe);
862 filename_for_input(sess, crate_type, id, &out_filename)
866 // Make sure the output and obj_filename are both writeable.
867 // Mac, FreeBSD, and Windows system linkers check this already --
868 // however, the Linux linker will happily overwrite a read-only file.
869 // We should be consistent.
870 let obj_is_writeable = is_writeable(&obj_filename);
871 let out_is_writeable = is_writeable(&out_filename);
872 if !out_is_writeable {
873 sess.fatal(format!("output file {} is not writeable -- check its \
875 out_filename.display()).as_slice());
877 else if !obj_is_writeable {
878 sess.fatal(format!("object file {} is not writeable -- check its \
880 obj_filename.display()).as_slice());
884 config::CrateTypeRlib => {
885 link_rlib(sess, Some(trans), &obj_filename, &out_filename);
887 config::CrateTypeStaticlib => {
888 link_staticlib(sess, &obj_filename, &out_filename);
890 config::CrateTypeExecutable => {
891 link_natively(sess, trans, false, &obj_filename, &out_filename);
893 config::CrateTypeDylib => {
894 link_natively(sess, trans, true, &obj_filename, &out_filename);
903 // An rlib in its current incarnation is essentially a renamed .a file. The
904 // rlib primarily contains the object file of the crate, but it also contains
905 // all of the object files from native libraries. This is done by unzipping
906 // native libraries and inserting all of the contents into this archive.
907 fn link_rlib<'a>(sess: &'a Session,
908 trans: Option<&CrateTranslation>, // None == no metadata/bytecode
910 out_filename: &Path) -> Archive<'a> {
911 let mut a = Archive::create(sess, out_filename, obj_filename);
913 for &(ref l, kind) in sess.cstore.get_used_libraries().borrow().iter() {
915 cstore::NativeStatic => {
916 a.add_native_library(l.as_slice()).unwrap();
918 cstore::NativeFramework | cstore::NativeUnknown => {}
922 // Note that it is important that we add all of our non-object "magical
923 // files" *after* all of the object files in the archive. The reason for
924 // this is as follows:
926 // * When performing LTO, this archive will be modified to remove
927 // obj_filename from above. The reason for this is described below.
929 // * When the system linker looks at an archive, it will attempt to
930 // determine the architecture of the archive in order to see whether its
933 // The algorithm for this detection is: iterate over the files in the
934 // archive. Skip magical SYMDEF names. Interpret the first file as an
935 // object file. Read architecture from the object file.
937 // * As one can probably see, if "metadata" and "foo.bc" were placed
938 // before all of the objects, then the architecture of this archive would
939 // not be correctly inferred once 'foo.o' is removed.
941 // Basically, all this means is that this code should not move above the
945 // Instead of putting the metadata in an object file section, rlibs
946 // contain the metadata in a separate file. We use a temp directory
947 // here so concurrent builds in the same directory don't try to use
948 // the same filename for metadata (stomping over one another)
949 let tmpdir = TempDir::new("rustc").expect("needs a temp dir");
950 let metadata = tmpdir.path().join(METADATA_FILENAME);
951 match fs::File::create(&metadata).write(trans.metadata
955 sess.err(format!("failed to write {}: {}",
958 sess.abort_if_errors();
961 a.add_file(&metadata, false);
962 remove(sess, &metadata);
964 // For LTO purposes, the bytecode of this library is also inserted
966 let bc = obj_filename.with_extension("bc");
967 let bc_deflated = obj_filename.with_extension("bc.deflate");
968 match fs::File::open(&bc).read_to_end().and_then(|data| {
969 fs::File::create(&bc_deflated)
970 .write(match flate::deflate_bytes(data.as_slice()) {
971 Some(compressed) => compressed,
972 None => sess.fatal("failed to compress bytecode")
977 sess.err(format!("failed to write compressed bytecode: \
980 sess.abort_if_errors()
983 a.add_file(&bc_deflated, false);
984 remove(sess, &bc_deflated);
985 if !sess.opts.cg.save_temps &&
986 !sess.opts.output_types.contains(&OutputTypeBitcode) {
990 // After adding all files to the archive, we need to update the
991 // symbol table of the archive. This currently dies on OSX (see
992 // #11162), and isn't necessary there anyway
993 match sess.targ_cfg.os {
995 _ => { a.update_symbols(); }
1004 // Create a static archive
1006 // This is essentially the same thing as an rlib, but it also involves adding
1007 // all of the upstream crates' objects into the archive. This will slurp in
1008 // all of the native libraries of upstream dependencies as well.
1010 // Additionally, there's no way for us to link dynamic libraries, so we warn
1011 // about all dynamic library dependencies that they're not linked in.
1013 // There's no need to include metadata in a static archive, so ensure to not
1014 // link in the metadata object file (and also don't prepare the archive with a
1016 fn link_staticlib(sess: &Session, obj_filename: &Path, out_filename: &Path) {
1017 let mut a = link_rlib(sess, None, obj_filename, out_filename);
1018 a.add_native_library("morestack").unwrap();
1019 a.add_native_library("compiler-rt").unwrap();
1021 let crates = sess.cstore.get_used_crates(cstore::RequireStatic);
1022 for &(cnum, ref path) in crates.iter() {
1023 let name = sess.cstore.get_crate_data(cnum).name.clone();
1024 let p = match *path {
1025 Some(ref p) => p.clone(), None => {
1026 sess.err(format!("could not find rlib for: `{}`",
1031 a.add_rlib(&p, name.as_slice(), sess.lto()).unwrap();
1032 let native_libs = csearch::get_native_libraries(&sess.cstore, cnum);
1033 for &(kind, ref lib) in native_libs.iter() {
1034 let name = match kind {
1035 cstore::NativeStatic => "static library",
1036 cstore::NativeUnknown => "library",
1037 cstore::NativeFramework => "framework",
1039 sess.warn(format!("unlinked native {}: {}",
1046 // Create a dynamic library or executable
1048 // This will invoke the system linker/cc to create the resulting file. This
1049 // links to all upstream files as well.
1050 fn link_natively(sess: &Session, trans: &CrateTranslation, dylib: bool,
1051 obj_filename: &Path, out_filename: &Path) {
1052 let tmpdir = TempDir::new("rustc").expect("needs a temp dir");
1054 // The invocations of cc share some flags across platforms
1055 let pname = get_cc_prog(sess);
1056 let mut cmd = Command::new(pname.as_slice());
1058 cmd.args(sess.targ_cfg.target_strs.cc_args.as_slice());
1059 link_args(&mut cmd, sess, dylib, tmpdir.path(),
1060 trans, obj_filename, out_filename);
1062 if (sess.opts.debugging_opts & config::PRINT_LINK_ARGS) != 0 {
1063 println!("{}", &cmd);
1066 // May have not found libraries in the right formats.
1067 sess.abort_if_errors();
1069 // Invoke the system linker
1071 let prog = time(sess.time_passes(), "running linker", (), |()| cmd.output());
1074 if !prog.status.success() {
1075 sess.err(format!("linking with `{}` failed: {}",
1077 prog.status).as_slice());
1078 sess.note(format!("{}", &cmd).as_slice());
1079 let mut output = prog.error.clone();
1080 output.push_all(prog.output.as_slice());
1081 sess.note(str::from_utf8(output.as_slice()).unwrap()
1083 sess.abort_if_errors();
1087 sess.err(format!("could not exec the linker `{}`: {}",
1090 sess.abort_if_errors();
1095 // On OSX, debuggers need this utility to get run to do some munging of
1097 if sess.targ_cfg.os == abi::OsMacos && (sess.opts.debuginfo != NoDebugInfo) {
1098 match Command::new("dsymutil").arg(out_filename).status() {
1101 sess.err(format!("failed to run dsymutil: {}", e).as_slice());
1102 sess.abort_if_errors();
1108 fn link_args(cmd: &mut Command,
1112 trans: &CrateTranslation,
1113 obj_filename: &Path,
1114 out_filename: &Path) {
1116 // The default library location, we need this to find the runtime.
1117 // The location of crates will be determined as needed.
1118 let lib_path = sess.target_filesearch().get_lib_path();
1119 cmd.arg("-L").arg(lib_path);
1121 cmd.arg("-o").arg(out_filename).arg(obj_filename);
1123 // Stack growth requires statically linking a __morestack function. Note
1124 // that this is listed *before* all other libraries, even though it may be
1125 // used to resolve symbols in other libraries. The only case that this
1126 // wouldn't be pulled in by the object file is if the object file had no
1129 // If we're building an executable, there must be at least one function (the
1130 // main function), and if we're building a dylib then we don't need it for
1131 // later libraries because they're all dylibs (not rlibs).
1133 // I'm honestly not entirely sure why this needs to come first. Apparently
1134 // the --as-needed flag above sometimes strips out libstd from the command
1135 // line, but inserting this farther to the left makes the
1136 // "rust_stack_exhausted" symbol an outstanding undefined symbol, which
1137 // flags libstd as a required library (or whatever provides the symbol).
1138 cmd.arg("-lmorestack");
1140 // When linking a dynamic library, we put the metadata into a section of the
1141 // executable. This metadata is in a separate object file from the main
1142 // object file, so we link that in here.
1144 cmd.arg(obj_filename.with_extension("metadata.o"));
1147 // We want to prevent the compiler from accidentally leaking in any system
1148 // libraries, so we explicitly ask gcc to not link to any libraries by
1149 // default. Note that this does not happen for windows because windows pulls
1150 // in some large number of libraries and I couldn't quite figure out which
1151 // subset we wanted.
1153 // FIXME(#11937) we should invoke the system linker directly
1154 if sess.targ_cfg.os != abi::OsWin32 {
1155 cmd.arg("-nodefaultlibs");
1158 // If we're building a dylib, we don't use --gc-sections because LLVM has
1159 // already done the best it can do, and we also don't want to eliminate the
1160 // metadata. If we're building an executable, however, --gc-sections drops
1161 // the size of hello world from 1.8MB to 597K, a 67% reduction.
1162 if !dylib && sess.targ_cfg.os != abi::OsMacos {
1163 cmd.arg("-Wl,--gc-sections");
1166 if sess.targ_cfg.os == abi::OsLinux {
1167 // GNU-style linkers will use this to omit linking to libraries which
1168 // don't actually fulfill any relocations, but only for libraries which
1169 // follow this flag. Thus, use it before specifying libraries to link to.
1170 cmd.arg("-Wl,--as-needed");
1172 // GNU-style linkers support optimization with -O. GNU ld doesn't need a
1173 // numeric argument, but other linkers do.
1174 if sess.opts.optimize == config::Default ||
1175 sess.opts.optimize == config::Aggressive {
1178 } else if sess.targ_cfg.os == abi::OsMacos {
1179 // The dead_strip option to the linker specifies that functions and data
1180 // unreachable by the entry point will be removed. This is quite useful
1181 // with Rust's compilation model of compiling libraries at a time into
1182 // one object file. For example, this brings hello world from 1.7MB to
1185 // Note that this is done for both executables and dynamic libraries. We
1186 // won't get much benefit from dylibs because LLVM will have already
1187 // stripped away as much as it could. This has not been seen to impact
1188 // link times negatively.
1189 cmd.arg("-Wl,-dead_strip");
1192 if sess.targ_cfg.os == abi::OsWin32 {
1193 // Make sure that we link to the dynamic libgcc, otherwise cross-module
1194 // DWARF stack unwinding will not work.
1195 // This behavior may be overridden by --link-args "-static-libgcc"
1196 cmd.arg("-shared-libgcc");
1198 // And here, we see obscure linker flags #45. On windows, it has been
1199 // found to be necessary to have this flag to compile liblibc.
1201 // First a bit of background. On Windows, the file format is not ELF,
1202 // but COFF (at least according to LLVM). COFF doesn't officially allow
1203 // for section names over 8 characters, apparently. Our metadata
1204 // section, ".note.rustc", you'll note is over 8 characters.
1206 // On more recent versions of gcc on mingw, apparently the section name
1207 // is *not* truncated, but rather stored elsewhere in a separate lookup
1208 // table. On older versions of gcc, they apparently always truncated the
1209 // section names (at least in some cases). Truncating the section name
1210 // actually creates "invalid" objects [1] [2], but only for some
1211 // introspection tools, not in terms of whether it can be loaded.
1213 // Long story short, passing this flag forces the linker to *not*
1214 // truncate section names (so we can find the metadata section after
1215 // it's compiled). The real kicker is that rust compiled just fine on
1216 // windows for quite a long time *without* this flag, so I have no idea
1217 // why it suddenly started failing for liblibc. Regardless, we
1218 // definitely don't want section name truncation, so we're keeping this
1219 // flag for windows.
1221 // [1] - https://sourceware.org/bugzilla/show_bug.cgi?id=13130
1222 // [2] - https://code.google.com/p/go/issues/detail?id=2139
1223 cmd.arg("-Wl,--enable-long-section-names");
1226 if sess.targ_cfg.os == abi::OsAndroid {
1227 // Many of the symbols defined in compiler-rt are also defined in libgcc.
1228 // Android linker doesn't like that by default.
1229 cmd.arg("-Wl,--allow-multiple-definition");
1232 // Take careful note of the ordering of the arguments we pass to the linker
1233 // here. Linkers will assume that things on the left depend on things to the
1234 // right. Things on the right cannot depend on things on the left. This is
1235 // all formally implemented in terms of resolving symbols (libs on the right
1236 // resolve unknown symbols of libs on the left, but not vice versa).
1238 // For this reason, we have organized the arguments we pass to the linker as
1241 // 1. The local object that LLVM just generated
1242 // 2. Upstream rust libraries
1243 // 3. Local native libraries
1244 // 4. Upstream native libraries
1246 // This is generally fairly natural, but some may expect 2 and 3 to be
1247 // swapped. The reason that all native libraries are put last is that it's
1248 // not recommended for a native library to depend on a symbol from a rust
1249 // crate. If this is the case then a staticlib crate is recommended, solving
1252 // Additionally, it is occasionally the case that upstream rust libraries
1253 // depend on a local native library. In the case of libraries such as
1254 // lua/glfw/etc the name of the library isn't the same across all platforms,
1255 // so only the consumer crate of a library knows the actual name. This means
1256 // that downstream crates will provide the #[link] attribute which upstream
1257 // crates will depend on. Hence local native libraries are after out
1258 // upstream rust crates.
1260 // In theory this means that a symbol in an upstream native library will be
1261 // shadowed by a local native library when it wouldn't have been before, but
1262 // this kind of behavior is pretty platform specific and generally not
1263 // recommended anyway, so I don't think we're shooting ourself in the foot
1265 add_upstream_rust_crates(cmd, sess, dylib, tmpdir, trans);
1266 add_local_native_libraries(cmd, sess);
1267 add_upstream_native_libraries(cmd, sess);
1269 // # Telling the linker what we're doing
1272 // On mac we need to tell the linker to let this library be rpathed
1273 if sess.targ_cfg.os == abi::OsMacos {
1274 cmd.args(["-dynamiclib", "-Wl,-dylib"]);
1276 if !sess.opts.cg.no_rpath {
1277 let mut v = Vec::from_slice("-Wl,-install_name,@rpath/".as_bytes());
1278 v.push_all(out_filename.filename().unwrap());
1279 cmd.arg(v.as_slice());
1286 if sess.targ_cfg.os == abi::OsFreebsd {
1287 cmd.args(["-L/usr/local/lib",
1288 "-L/usr/local/lib/gcc46",
1289 "-L/usr/local/lib/gcc44"]);
1292 // FIXME (#2397): At some point we want to rpath our guesses as to
1293 // where extern libraries might live, based on the
1294 // addl_lib_search_paths
1295 if !sess.opts.cg.no_rpath {
1296 cmd.args(rpath::get_rpath_flags(sess, out_filename).as_slice());
1299 // compiler-rt contains implementations of low-level LLVM helpers. This is
1300 // used to resolve symbols from the object file we just created, as well as
1301 // any system static libraries that may be expecting gcc instead. Most
1302 // symbols in libgcc also appear in compiler-rt.
1304 // This is the end of the command line, so this library is used to resolve
1305 // *all* undefined symbols in all other libraries, and this is intentional.
1306 cmd.arg("-lcompiler-rt");
1308 // Finally add all the linker arguments provided on the command line along
1309 // with any #[link_args] attributes found inside the crate
1310 cmd.args(sess.opts.cg.link_args.as_slice());
1311 for arg in sess.cstore.get_used_link_args().borrow().iter() {
1312 cmd.arg(arg.as_slice());
1316 // # Native library linking
1318 // User-supplied library search paths (-L on the command line). These are
1319 // the same paths used to find Rust crates, so some of them may have been
1320 // added already by the previous crate linking code. This only allows them
1321 // to be found at compile time so it is still entirely up to outside
1322 // forces to make sure that library can be found at runtime.
1324 // Also note that the native libraries linked here are only the ones located
1325 // in the current crate. Upstream crates with native library dependencies
1326 // may have their native library pulled in above.
1327 fn add_local_native_libraries(cmd: &mut Command, sess: &Session) {
1328 for path in sess.opts.addl_lib_search_paths.borrow().iter() {
1329 cmd.arg("-L").arg(path);
1332 let rustpath = filesearch::rust_path();
1333 for path in rustpath.iter() {
1334 cmd.arg("-L").arg(path);
1337 // Some platforms take hints about whether a library is static or dynamic.
1338 // For those that support this, we ensure we pass the option if the library
1339 // was flagged "static" (most defaults are dynamic) to ensure that if
1340 // libfoo.a and libfoo.so both exist that the right one is chosen.
1341 let takes_hints = sess.targ_cfg.os != abi::OsMacos;
1343 for &(ref l, kind) in sess.cstore.get_used_libraries().borrow().iter() {
1345 cstore::NativeUnknown | cstore::NativeStatic => {
1347 if kind == cstore::NativeStatic {
1348 cmd.arg("-Wl,-Bstatic");
1350 cmd.arg("-Wl,-Bdynamic");
1353 cmd.arg(format_strbuf!("-l{}", *l));
1355 cstore::NativeFramework => {
1356 cmd.arg("-framework");
1357 cmd.arg(l.as_slice());
1362 cmd.arg("-Wl,-Bdynamic");
1366 // # Rust Crate linking
1368 // Rust crates are not considered at all when creating an rlib output. All
1369 // dependencies will be linked when producing the final output (instead of
1370 // the intermediate rlib version)
1371 fn add_upstream_rust_crates(cmd: &mut Command, sess: &Session,
1372 dylib: bool, tmpdir: &Path,
1373 trans: &CrateTranslation) {
1374 // All of the heavy lifting has previously been accomplished by the
1375 // dependency_format module of the compiler. This is just crawling the
1376 // output of that module, adding crates as necessary.
1378 // Linking to a rlib involves just passing it to the linker (the linker
1379 // will slurp up the object files inside), and linking to a dynamic library
1380 // involves just passing the right -l flag.
1382 let data = if dylib {
1383 trans.crate_formats.get(&config::CrateTypeDylib)
1385 trans.crate_formats.get(&config::CrateTypeExecutable)
1388 // Invoke get_used_crates to ensure that we get a topological sorting of
1390 let deps = sess.cstore.get_used_crates(cstore::RequireDynamic);
1392 for &(cnum, _) in deps.iter() {
1393 // We may not pass all crates through to the linker. Some crates may
1394 // appear statically in an existing dylib, meaning we'll pick up all the
1395 // symbols from the dylib.
1396 let kind = match *data.get(cnum as uint - 1) {
1400 let src = sess.cstore.get_used_crate_source(cnum).unwrap();
1402 cstore::RequireDynamic => {
1403 add_dynamic_crate(cmd, sess, src.dylib.unwrap())
1405 cstore::RequireStatic => {
1406 add_static_crate(cmd, sess, tmpdir, cnum, src.rlib.unwrap())
1412 // Converts a library file-stem into a cc -l argument
1413 fn unlib<'a>(config: &config::Config, stem: &'a [u8]) -> &'a [u8] {
1414 if stem.starts_with("lib".as_bytes()) && config.os != abi::OsWin32 {
1421 // Adds the static "rlib" versions of all crates to the command line.
1422 fn add_static_crate(cmd: &mut Command, sess: &Session, tmpdir: &Path,
1423 cnum: ast::CrateNum, cratepath: Path) {
1424 // When performing LTO on an executable output, all of the
1425 // bytecode from the upstream libraries has already been
1426 // included in our object file output. We need to modify all of
1427 // the upstream archives to remove their corresponding object
1428 // file to make sure we don't pull the same code in twice.
1430 // We must continue to link to the upstream archives to be sure
1431 // to pull in native static dependencies. As the final caveat,
1432 // on linux it is apparently illegal to link to a blank archive,
1433 // so if an archive no longer has any object files in it after
1434 // we remove `lib.o`, then don't link against it at all.
1436 // If we're not doing LTO, then our job is simply to just link
1437 // against the archive.
1439 let name = sess.cstore.get_crate_data(cnum).name.clone();
1440 time(sess.time_passes(),
1441 format!("altering {}.rlib", name).as_slice(),
1443 let dst = tmpdir.join(cratepath.filename().unwrap());
1444 match fs::copy(&cratepath, &dst) {
1447 sess.err(format!("failed to copy {} to {}: {}",
1448 cratepath.display(),
1451 sess.abort_if_errors();
1454 let mut archive = Archive::open(sess, dst.clone());
1455 archive.remove_file(format!("{}.o", name).as_slice());
1456 let files = archive.files();
1457 if files.iter().any(|s| s.as_slice().ends_with(".o")) {
1466 // Same thing as above, but for dynamic crates instead of static crates.
1467 fn add_dynamic_crate(cmd: &mut Command, sess: &Session, cratepath: Path) {
1468 // If we're performing LTO, then it should have been previously required
1469 // that all upstream rust dependencies were available in an rlib format.
1470 assert!(!sess.lto());
1472 // Just need to tell the linker about where the library lives and
1474 let dir = cratepath.dirname();
1475 if !dir.is_empty() { cmd.arg("-L").arg(dir); }
1477 let mut v = Vec::from_slice("-l".as_bytes());
1478 v.push_all(unlib(&sess.targ_cfg, cratepath.filestem().unwrap()));
1479 cmd.arg(v.as_slice());
1483 // Link in all of our upstream crates' native dependencies. Remember that
1484 // all of these upstream native dependencies are all non-static
1485 // dependencies. We've got two cases then:
1487 // 1. The upstream crate is an rlib. In this case we *must* link in the
1488 // native dependency because the rlib is just an archive.
1490 // 2. The upstream crate is a dylib. In order to use the dylib, we have to
1491 // have the dependency present on the system somewhere. Thus, we don't
1492 // gain a whole lot from not linking in the dynamic dependency to this
1495 // The use case for this is a little subtle. In theory the native
1496 // dependencies of a crate are purely an implementation detail of the crate
1497 // itself, but the problem arises with generic and inlined functions. If a
1498 // generic function calls a native function, then the generic function must
1499 // be instantiated in the target crate, meaning that the native symbol must
1500 // also be resolved in the target crate.
1501 fn add_upstream_native_libraries(cmd: &mut Command, sess: &Session) {
1502 // Be sure to use a topological sorting of crates because there may be
1503 // interdependencies between native libraries. When passing -nodefaultlibs,
1504 // for example, almost all native libraries depend on libc, so we have to
1505 // make sure that's all the way at the right (liblibc is near the base of
1506 // the dependency chain).
1508 // This passes RequireStatic, but the actual requirement doesn't matter,
1509 // we're just getting an ordering of crate numbers, we're not worried about
1511 let crates = sess.cstore.get_used_crates(cstore::RequireStatic);
1512 for (cnum, _) in crates.move_iter() {
1513 let libs = csearch::get_native_libraries(&sess.cstore, cnum);
1514 for &(kind, ref lib) in libs.iter() {
1516 cstore::NativeUnknown => {
1517 cmd.arg(format_strbuf!("-l{}", *lib));
1519 cstore::NativeFramework => {
1520 cmd.arg("-framework");
1521 cmd.arg(lib.as_slice());
1523 cstore::NativeStatic => {
1524 sess.bug("statics shouldn't be propagated");