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::session::{NoDebugInfo, Session};
18 use lib::llvm::ModuleRef;
20 use metadata::common::LinkMeta;
21 use metadata::{encoder, cstore, filesearch, csearch};
22 use middle::trans::context::CrateContext;
23 use middle::trans::common::gensym_name;
25 use util::common::time;
27 use util::sha2::{Digest, Sha256};
29 use std::c_str::{ToCStr, CString};
31 use std::os::consts::{macos, freebsd, linux, android, win32};
35 use std::io::{fs, TempDir, Process};
37 use serialize::hex::ToHex;
40 use syntax::ast_map::{PathElem, PathElems, PathName};
43 use syntax::attr::AttrMetaMethods;
44 use syntax::crateid::CrateId;
45 use syntax::parse::token;
47 #[deriving(Clone, Eq, Ord, TotalOrd, TotalEq)]
51 OutputTypeLlvmAssembly,
56 pub fn llvm_err(sess: &Session, msg: ~str) -> ! {
58 let cstr = llvm::LLVMRustGetLastError();
59 if cstr == ptr::null() {
62 let err = CString::new(cstr, false);
63 let err = str::from_utf8_lossy(err.as_bytes());
64 sess.fatal(msg + ": " + err.as_slice());
69 pub fn WriteOutputFile(
71 target: lib::llvm::TargetMachineRef,
72 pm: lib::llvm::PassManagerRef,
75 file_type: lib::llvm::FileType) {
77 output.with_c_str(|output| {
78 let result = llvm::LLVMRustWriteOutputFile(
79 target, pm, m, output, file_type);
81 llvm_err(sess, ~"could not write output");
90 use back::link::{WriteOutputFile, OutputType};
91 use back::link::{OutputTypeAssembly, OutputTypeBitcode};
92 use back::link::{OutputTypeExe, OutputTypeLlvmAssembly};
93 use back::link::{OutputTypeObject};
94 use driver::driver::{CrateTranslation, OutputFilenames};
95 use driver::session::{NoDebugInfo, Session};
98 use lib::llvm::{ModuleRef, TargetMachineRef, PassManagerRef};
100 use util::common::time;
103 use std::c_str::ToCStr;
104 use std::io::Process;
105 use libc::{c_uint, c_int};
108 // On android, we by default compile for armv7 processors. This enables
109 // things like double word CAS instructions (rather than emulating them)
110 // which are *far* more efficient. This is obviously undesirable in some
111 // cases, so if any sort of target feature is specified we don't append v7
112 // to the feature list.
113 fn target_feature<'a>(sess: &'a Session) -> &'a str {
114 match sess.targ_cfg.os {
116 if "" == sess.opts.cg.target_feature {
119 sess.opts.cg.target_feature.as_slice()
122 _ => sess.opts.cg.target_feature.as_slice()
126 pub fn run_passes(sess: &Session,
127 trans: &CrateTranslation,
128 output_types: &[OutputType],
129 output: &OutputFilenames) {
130 let llmod = trans.module;
131 let llcx = trans.context;
133 configure_llvm(sess);
135 if sess.opts.cg.save_temps {
136 output.with_extension("no-opt.bc").with_c_str(|buf| {
137 llvm::LLVMWriteBitcodeToFile(llmod, buf);
141 let opt_level = match sess.opts.optimize {
142 session::No => lib::llvm::CodeGenLevelNone,
143 session::Less => lib::llvm::CodeGenLevelLess,
144 session::Default => lib::llvm::CodeGenLevelDefault,
145 session::Aggressive => lib::llvm::CodeGenLevelAggressive,
147 let use_softfp = sess.opts.cg.soft_float;
149 // FIXME: #11906: Omitting frame pointers breaks retrieving the value of a parameter.
150 // FIXME: #11954: mac64 unwinding may not work with fp elim
151 let no_fp_elim = (sess.opts.debuginfo != NoDebugInfo) ||
152 (sess.targ_cfg.os == abi::OsMacos &&
153 sess.targ_cfg.arch == abi::X86_64);
155 let reloc_model = match sess.opts.cg.relocation_model.as_slice() {
156 "pic" => lib::llvm::RelocPIC,
157 "static" => lib::llvm::RelocStatic,
158 "default" => lib::llvm::RelocDefault,
159 "dynamic-no-pic" => lib::llvm::RelocDynamicNoPic,
161 sess.err(format!("{} is not a valid relocation mode",
162 sess.opts.cg.relocation_model));
163 sess.abort_if_errors();
168 let tm = sess.targ_cfg.target_strs.target_triple.with_c_str(|t| {
169 sess.opts.cg.target_cpu.with_c_str(|cpu| {
170 target_feature(sess).with_c_str(|features| {
171 llvm::LLVMRustCreateTargetMachine(
173 lib::llvm::CodeModelDefault,
184 // Create the two optimizing pass managers. These mirror what clang
185 // does, and are by populated by LLVM's default PassManagerBuilder.
186 // Each manager has a different set of passes, but they also share
187 // some common passes.
188 let fpm = llvm::LLVMCreateFunctionPassManagerForModule(llmod);
189 let mpm = llvm::LLVMCreatePassManager();
191 // If we're verifying or linting, add them to the function pass
193 let addpass = |pass: &str| {
194 pass.with_c_str(|s| llvm::LLVMRustAddPass(fpm, s))
196 if !sess.no_verify() { assert!(addpass("verify")); }
198 if !sess.opts.cg.no_prepopulate_passes {
199 llvm::LLVMRustAddAnalysisPasses(tm, fpm, llmod);
200 llvm::LLVMRustAddAnalysisPasses(tm, mpm, llmod);
201 populate_llvm_passes(fpm, mpm, llmod, opt_level);
204 for pass in sess.opts.cg.passes.iter() {
205 pass.with_c_str(|s| {
206 if !llvm::LLVMRustAddPass(mpm, s) {
207 sess.warn(format!("unknown pass {}, ignoring", *pass));
212 // Finally, run the actual optimization passes
213 time(sess.time_passes(), "llvm function passes", (), |()|
214 llvm::LLVMRustRunFunctionPassManager(fpm, llmod));
215 time(sess.time_passes(), "llvm module passes", (), |()|
216 llvm::LLVMRunPassManager(mpm, llmod));
218 // Deallocate managers that we're now done with
219 llvm::LLVMDisposePassManager(fpm);
220 llvm::LLVMDisposePassManager(mpm);
222 // Emit the bytecode if we're either saving our temporaries or
223 // emitting an rlib. Whenever an rlib is created, the bytecode is
224 // inserted into the archive in order to allow LTO against it.
225 if sess.opts.cg.save_temps ||
226 (sess.crate_types.borrow().contains(&session::CrateTypeRlib) &&
227 sess.opts.output_types.contains(&OutputTypeExe)) {
228 output.temp_path(OutputTypeBitcode).with_c_str(|buf| {
229 llvm::LLVMWriteBitcodeToFile(llmod, buf);
234 time(sess.time_passes(), "all lto passes", (), |()|
235 lto::run(sess, llmod, tm, trans.reachable.as_slice()));
237 if sess.opts.cg.save_temps {
238 output.with_extension("lto.bc").with_c_str(|buf| {
239 llvm::LLVMWriteBitcodeToFile(llmod, buf);
244 // A codegen-specific pass manager is used to generate object
245 // files for an LLVM module.
247 // Apparently each of these pass managers is a one-shot kind of
248 // thing, so we create a new one for each type of output. The
249 // pass manager passed to the closure should be ensured to not
250 // escape the closure itself, and the manager should only be
252 fn with_codegen(tm: TargetMachineRef, llmod: ModuleRef,
253 f: |PassManagerRef|) {
255 let cpm = llvm::LLVMCreatePassManager();
256 llvm::LLVMRustAddAnalysisPasses(tm, cpm, llmod);
257 llvm::LLVMRustAddLibraryInfo(cpm, llmod);
259 llvm::LLVMDisposePassManager(cpm);
263 let mut object_file = None;
264 let mut needs_metadata = false;
265 for output_type in output_types.iter() {
266 let path = output.path(*output_type);
268 OutputTypeBitcode => {
269 path.with_c_str(|buf| {
270 llvm::LLVMWriteBitcodeToFile(llmod, buf);
273 OutputTypeLlvmAssembly => {
274 path.with_c_str(|output| {
275 with_codegen(tm, llmod, |cpm| {
276 llvm::LLVMRustPrintModule(cpm, llmod, output);
280 OutputTypeAssembly => {
281 // If we're not using the LLVM assembler, this function
282 // could be invoked specially with output_type_assembly,
283 // so in this case we still want the metadata object
285 let ty = OutputTypeAssembly;
286 let path = if sess.opts.output_types.contains(&ty) {
289 needs_metadata = true;
290 output.temp_path(OutputTypeAssembly)
292 with_codegen(tm, llmod, |cpm| {
293 WriteOutputFile(sess, tm, cpm, llmod, &path,
294 lib::llvm::AssemblyFile);
297 OutputTypeObject => {
298 object_file = Some(path);
301 object_file = Some(output.temp_path(OutputTypeObject));
302 needs_metadata = true;
307 time(sess.time_passes(), "codegen passes", (), |()| {
310 with_codegen(tm, llmod, |cpm| {
311 WriteOutputFile(sess, tm, cpm, llmod, path,
312 lib::llvm::ObjectFile);
318 with_codegen(tm, trans.metadata_module, |cpm| {
319 let out = output.temp_path(OutputTypeObject)
320 .with_extension("metadata.o");
321 WriteOutputFile(sess, tm, cpm,
322 trans.metadata_module, &out,
323 lib::llvm::ObjectFile);
328 llvm::LLVMRustDisposeTargetMachine(tm);
329 llvm::LLVMDisposeModule(trans.metadata_module);
330 llvm::LLVMDisposeModule(llmod);
331 llvm::LLVMContextDispose(llcx);
332 if sess.time_llvm_passes() { llvm::LLVMRustPrintPassTimings(); }
336 pub fn run_assembler(sess: &Session, outputs: &OutputFilenames) {
337 let cc = super::get_cc_prog(sess);
338 let assembly = outputs.temp_path(OutputTypeAssembly);
339 let object = outputs.path(OutputTypeObject);
341 // FIXME (#9639): This needs to handle non-utf8 paths
344 ~"-o", object.as_str().unwrap().to_owned(),
345 assembly.as_str().unwrap().to_owned()];
347 debug!("{} '{}'", cc, args.connect("' '"));
348 match Process::output(cc, args) {
350 if !prog.status.success() {
351 sess.err(format!("linking with `{}` failed: {}", cc, prog.status));
352 sess.note(format!("{} arguments: '{}'", cc, args.connect("' '")));
353 sess.note(str::from_utf8_owned(prog.error + prog.output).unwrap());
354 sess.abort_if_errors();
358 sess.err(format!("could not exec the linker `{}`: {}", cc, e));
359 sess.abort_if_errors();
364 unsafe fn configure_llvm(sess: &Session) {
365 use sync::one::{Once, ONCE_INIT};
366 static mut INIT: Once = ONCE_INIT;
368 // Copy what clang does by turning on loop vectorization at O2 and
369 // slp vectorization at O3
370 let vectorize_loop = !sess.opts.cg.no_vectorize_loops &&
371 (sess.opts.optimize == session::Default ||
372 sess.opts.optimize == session::Aggressive);
373 let vectorize_slp = !sess.opts.cg.no_vectorize_slp &&
374 sess.opts.optimize == session::Aggressive;
376 let mut llvm_c_strs = Vec::new();
377 let mut llvm_args = Vec::new();
379 let add = |arg: &str| {
380 let s = arg.to_c_str();
381 llvm_args.push(s.with_ref(|p| p));
384 add("rustc"); // fake program name
385 if vectorize_loop { add("-vectorize-loops"); }
386 if vectorize_slp { add("-vectorize-slp"); }
387 if sess.time_llvm_passes() { add("-time-passes"); }
388 if sess.print_llvm_passes() { add("-debug-pass=Structure"); }
390 for arg in sess.opts.cg.llvm_args.iter() {
396 llvm::LLVMInitializePasses();
398 // Only initialize the platforms supported by Rust here, because
399 // using --llvm-root will have multiple platforms that rustllvm
400 // doesn't actually link to and it's pointless to put target info
401 // into the registry that Rust cannot generate machine code for.
402 llvm::LLVMInitializeX86TargetInfo();
403 llvm::LLVMInitializeX86Target();
404 llvm::LLVMInitializeX86TargetMC();
405 llvm::LLVMInitializeX86AsmPrinter();
406 llvm::LLVMInitializeX86AsmParser();
408 llvm::LLVMInitializeARMTargetInfo();
409 llvm::LLVMInitializeARMTarget();
410 llvm::LLVMInitializeARMTargetMC();
411 llvm::LLVMInitializeARMAsmPrinter();
412 llvm::LLVMInitializeARMAsmParser();
414 llvm::LLVMInitializeMipsTargetInfo();
415 llvm::LLVMInitializeMipsTarget();
416 llvm::LLVMInitializeMipsTargetMC();
417 llvm::LLVMInitializeMipsAsmPrinter();
418 llvm::LLVMInitializeMipsAsmParser();
420 llvm::LLVMRustSetLLVMOptions(llvm_args.len() as c_int,
425 unsafe fn populate_llvm_passes(fpm: lib::llvm::PassManagerRef,
426 mpm: lib::llvm::PassManagerRef,
428 opt: lib::llvm::CodeGenOptLevel) {
429 // Create the PassManagerBuilder for LLVM. We configure it with
430 // reasonable defaults and prepare it to actually populate the pass
432 let builder = llvm::LLVMPassManagerBuilderCreate();
434 lib::llvm::CodeGenLevelNone => {
435 // Don't add lifetime intrinsics at O0
436 llvm::LLVMRustAddAlwaysInlinePass(builder, false);
438 lib::llvm::CodeGenLevelLess => {
439 llvm::LLVMRustAddAlwaysInlinePass(builder, true);
441 // numeric values copied from clang
442 lib::llvm::CodeGenLevelDefault => {
443 llvm::LLVMPassManagerBuilderUseInlinerWithThreshold(builder,
446 lib::llvm::CodeGenLevelAggressive => {
447 llvm::LLVMPassManagerBuilderUseInlinerWithThreshold(builder,
451 llvm::LLVMPassManagerBuilderSetOptLevel(builder, opt as c_uint);
452 llvm::LLVMRustAddBuilderLibraryInfo(builder, llmod);
454 // Use the builder to populate the function/module pass managers.
455 llvm::LLVMPassManagerBuilderPopulateFunctionPassManager(builder, fpm);
456 llvm::LLVMPassManagerBuilderPopulateModulePassManager(builder, mpm);
457 llvm::LLVMPassManagerBuilderDispose(builder);
463 * Name mangling and its relationship to metadata. This is complex. Read
466 * The semantic model of Rust linkage is, broadly, that "there's no global
467 * namespace" between crates. Our aim is to preserve the illusion of this
468 * model despite the fact that it's not *quite* possible to implement on
469 * modern linkers. We initially didn't use system linkers at all, but have
470 * been convinced of their utility.
472 * There are a few issues to handle:
474 * - Linkers operate on a flat namespace, so we have to flatten names.
475 * We do this using the C++ namespace-mangling technique. Foo::bar
478 * - Symbols with the same name but different types need to get different
479 * linkage-names. We do this by hashing a string-encoding of the type into
480 * a fixed-size (currently 16-byte hex) cryptographic hash function (CHF:
481 * we use SHA256) to "prevent collisions". This is not airtight but 16 hex
482 * digits on uniform probability means you're going to need 2**32 same-name
483 * symbols in the same process before you're even hitting birthday-paradox
484 * collision probability.
486 * - Symbols in different crates but with same names "within" the crate need
487 * to get different linkage-names.
489 * - The hash shown in the filename needs to be predictable and stable for
490 * build tooling integration. It also needs to be using a hash function
491 * which is easy to use from Python, make, etc.
493 * So here is what we do:
495 * - Consider the package id; every crate has one (specified with crate_id
496 * attribute). If a package id isn't provided explicitly, we infer a
497 * versionless one from the output name. The version will end up being 0.0
498 * in this case. CNAME and CVERS are taken from this package id. For
499 * example, github.com/mozilla/CNAME#CVERS.
501 * - Define CMH as SHA256(crateid).
503 * - Define CMH8 as the first 8 characters of CMH.
505 * - Compile our crate to lib CNAME-CMH8-CVERS.so
507 * - Define STH(sym) as SHA256(CMH, type_str(sym))
509 * - Suffix a mangled sym with ::STH@CVERS, so that it is unique in the
510 * name, non-name metadata, and type sense, and versioned in the way
511 * system linkers understand.
514 pub fn find_crate_id(attrs: &[ast::Attribute], out_filestem: &str) -> CrateId {
515 match attr::find_crateid(attrs) {
516 None => from_str(out_filestem).unwrap(),
521 pub fn crate_id_hash(crate_id: &CrateId) -> ~str {
522 // This calculates CMH as defined above. Note that we don't use the path of
523 // the crate id in the hash because lookups are only done by (name/vers),
525 let mut s = Sha256::new();
526 s.input_str(crate_id.short_name_with_version());
527 truncated_hash_result(&mut s).slice_to(8).to_owned()
530 pub fn build_link_meta(krate: &ast::Crate, out_filestem: &str) -> LinkMeta {
532 crateid: find_crate_id(krate.attrs.as_slice(), out_filestem),
533 crate_hash: Svh::calculate(krate),
539 fn truncated_hash_result(symbol_hasher: &mut Sha256) -> ~str {
540 let output = symbol_hasher.result_bytes();
541 // 64 bits should be enough to avoid collisions.
542 output.slice_to(8).to_hex()
546 // This calculates STH for a symbol, as defined above
547 fn symbol_hash(tcx: &ty::ctxt, symbol_hasher: &mut Sha256,
548 t: ty::t, link_meta: &LinkMeta) -> ~str {
549 // NB: do *not* use abbrevs here as we want the symbol names
550 // to be independent of one another in the crate.
552 symbol_hasher.reset();
553 symbol_hasher.input_str(link_meta.crateid.name);
554 symbol_hasher.input_str("-");
555 symbol_hasher.input_str(link_meta.crate_hash.as_str());
556 symbol_hasher.input_str("-");
557 symbol_hasher.input_str(encoder::encoded_ty(tcx, t));
558 let mut hash = truncated_hash_result(symbol_hasher);
559 // Prefix with 'h' so that it never blends into adjacent digits
560 hash.unshift_char('h');
564 fn get_symbol_hash(ccx: &CrateContext, t: ty::t) -> ~str {
565 match ccx.type_hashcodes.borrow().find(&t) {
566 Some(h) => return h.to_str(),
570 let mut symbol_hasher = ccx.symbol_hasher.borrow_mut();
571 let hash = symbol_hash(ccx.tcx(), &mut *symbol_hasher, t, &ccx.link_meta);
572 ccx.type_hashcodes.borrow_mut().insert(t, hash.clone());
577 // Name sanitation. LLVM will happily accept identifiers with weird names, but
579 // gas accepts the following characters in symbols: a-z, A-Z, 0-9, ., _, $
580 pub fn sanitize(s: &str) -> ~str {
581 let mut result = ~"";
584 // Escape these with $ sequences
585 '@' => result.push_str("$SP$"),
586 '~' => result.push_str("$UP$"),
587 '*' => result.push_str("$RP$"),
588 '&' => result.push_str("$BP$"),
589 '<' => result.push_str("$LT$"),
590 '>' => result.push_str("$GT$"),
591 '(' => result.push_str("$LP$"),
592 ')' => result.push_str("$RP$"),
593 ',' => result.push_str("$C$"),
595 // '.' doesn't occur in types and functions, so reuse it
597 '-' | ':' => result.push_char('.'),
599 // These are legal symbols
603 | '_' | '.' | '$' => result.push_char(c),
607 char::escape_unicode(c, |c| tstr.push_char(c));
608 result.push_char('$');
609 result.push_str(tstr.slice_from(1));
614 // Underscore-qualify anything that didn't start as an ident.
615 if result.len() > 0u &&
616 result[0] != '_' as u8 &&
617 ! char::is_XID_start(result[0] as char) {
618 return ~"_" + result;
624 pub fn mangle<PI: Iterator<PathElem>>(mut path: PI,
626 vers: Option<&str>) -> ~str {
627 // Follow C++ namespace-mangling style, see
628 // http://en.wikipedia.org/wiki/Name_mangling for more info.
630 // It turns out that on OSX you can actually have arbitrary symbols in
631 // function names (at least when given to LLVM), but this is not possible
632 // when using unix's linker. Perhaps one day when we just use a linker from LLVM
633 // we won't need to do this name mangling. The problem with name mangling is
634 // that it seriously limits the available characters. For example we can't
635 // have things like &T or ~[T] in symbol names when one would theoretically
636 // want them for things like impls of traits on that type.
638 // To be able to work on all platforms and get *some* reasonable output, we
639 // use C++ name-mangling.
641 let mut n = ~"_ZN"; // _Z == Begin name-sequence, N == nested
643 fn push(n: &mut ~str, s: &str) {
644 let sani = sanitize(s);
645 n.push_str(format!("{}{}", sani.len(), sani));
648 // First, connect each component with <len, name> pairs.
650 push(&mut n, token::get_name(e.name()).get().as_slice())
654 Some(s) => push(&mut n, s),
658 Some(s) => push(&mut n, s),
662 n.push_char('E'); // End name-sequence.
666 pub fn exported_name(path: PathElems, hash: &str, vers: &str) -> ~str {
667 // The version will get mangled to have a leading '_', but it makes more
668 // sense to lead with a 'v' b/c this is a version...
669 let vers = if vers.len() > 0 && !char::is_XID_start(vers.char_at(0)) {
675 mangle(path, Some(hash), Some(vers.as_slice()))
678 pub fn mangle_exported_name(ccx: &CrateContext, path: PathElems,
679 t: ty::t, id: ast::NodeId) -> ~str {
680 let mut hash = get_symbol_hash(ccx, t);
682 // Paths can be completely identical for different nodes,
683 // e.g. `fn foo() { { fn a() {} } { fn a() {} } }`, so we
684 // generate unique characters from the node id. For now
685 // hopefully 3 characters is enough to avoid collisions.
686 static EXTRA_CHARS: &'static str =
687 "abcdefghijklmnopqrstuvwxyz\
688 ABCDEFGHIJKLMNOPQRSTUVWXYZ\
691 let extra1 = id % EXTRA_CHARS.len();
692 let id = id / EXTRA_CHARS.len();
693 let extra2 = id % EXTRA_CHARS.len();
694 let id = id / EXTRA_CHARS.len();
695 let extra3 = id % EXTRA_CHARS.len();
696 hash.push_char(EXTRA_CHARS[extra1] as char);
697 hash.push_char(EXTRA_CHARS[extra2] as char);
698 hash.push_char(EXTRA_CHARS[extra3] as char);
700 exported_name(path, hash, ccx.link_meta.crateid.version_or_default())
703 pub fn mangle_internal_name_by_type_and_seq(ccx: &CrateContext,
705 name: &str) -> ~str {
706 let s = ppaux::ty_to_str(ccx.tcx(), t);
707 let path = [PathName(token::intern(s)),
709 let hash = get_symbol_hash(ccx, t);
710 mangle(ast_map::Values(path.iter()), Some(hash.as_slice()), None)
713 pub fn mangle_internal_name_by_path_and_seq(path: PathElems, flav: &str) -> ~str {
714 mangle(path.chain(Some(gensym_name(flav)).move_iter()), None, None)
717 pub fn output_lib_filename(id: &CrateId) -> ~str {
718 format!("{}-{}-{}", id.name, crate_id_hash(id), id.version_or_default())
721 pub fn get_cc_prog(sess: &Session) -> ~str {
722 match sess.opts.cg.linker {
723 Some(ref linker) => return linker.to_owned(),
727 // In the future, FreeBSD will use clang as default compiler.
728 // It would be flexible to use cc (system's default C compiler)
729 // instead of hard-coded gcc.
730 // For win32, there is no cc command, so we add a condition to make it use gcc.
731 match sess.targ_cfg.os {
732 abi::OsWin32 => return ~"gcc",
736 get_system_tool(sess, "cc")
739 pub fn get_ar_prog(sess: &Session) -> ~str {
740 match sess.opts.cg.ar {
741 Some(ref ar) => return ar.to_owned(),
745 get_system_tool(sess, "ar")
748 fn get_system_tool(sess: &Session, tool: &str) -> ~str {
749 match sess.targ_cfg.os {
750 abi::OsAndroid => match sess.opts.cg.android_cross_path {
752 let tool_str = match tool {
756 format!("{}/bin/arm-linux-androideabi-{}", *path, tool_str)
759 sess.fatal(format!("need Android NDK path for the '{}' tool \
760 (-C android-cross-path)", tool))
763 _ => tool.to_owned(),
767 fn remove(sess: &Session, path: &Path) {
768 match fs::unlink(path) {
771 sess.err(format!("failed to remove {}: {}", path.display(), e));
776 /// Perform the linkage portion of the compilation phase. This will generate all
777 /// of the requested outputs for this compilation session.
778 pub fn link_binary(sess: &Session,
779 trans: &CrateTranslation,
780 outputs: &OutputFilenames,
781 id: &CrateId) -> Vec<Path> {
782 let mut out_filenames = Vec::new();
783 for &crate_type in sess.crate_types.borrow().iter() {
784 let out_file = link_binary_output(sess, trans, crate_type, outputs, id);
785 out_filenames.push(out_file);
788 // Remove the temporary object file and metadata if we aren't saving temps
789 if !sess.opts.cg.save_temps {
790 let obj_filename = outputs.temp_path(OutputTypeObject);
791 if !sess.opts.output_types.contains(&OutputTypeObject) {
792 remove(sess, &obj_filename);
794 remove(sess, &obj_filename.with_extension("metadata.o"));
800 fn is_writeable(p: &Path) -> bool {
803 Ok(m) => m.perm & io::UserWrite == io::UserWrite
807 pub fn filename_for_input(sess: &Session, crate_type: session::CrateType,
808 id: &CrateId, out_filename: &Path) -> Path {
809 let libname = output_lib_filename(id);
811 session::CrateTypeRlib => {
812 out_filename.with_filename(format!("lib{}.rlib", libname))
814 session::CrateTypeDylib => {
815 let (prefix, suffix) = match sess.targ_cfg.os {
816 abi::OsWin32 => (win32::DLL_PREFIX, win32::DLL_SUFFIX),
817 abi::OsMacos => (macos::DLL_PREFIX, macos::DLL_SUFFIX),
818 abi::OsLinux => (linux::DLL_PREFIX, linux::DLL_SUFFIX),
819 abi::OsAndroid => (android::DLL_PREFIX, android::DLL_SUFFIX),
820 abi::OsFreebsd => (freebsd::DLL_PREFIX, freebsd::DLL_SUFFIX),
822 out_filename.with_filename(format!("{}{}{}", prefix, libname, suffix))
824 session::CrateTypeStaticlib => {
825 out_filename.with_filename(format!("lib{}.a", libname))
827 session::CrateTypeExecutable => out_filename.clone(),
831 fn link_binary_output(sess: &Session,
832 trans: &CrateTranslation,
833 crate_type: session::CrateType,
834 outputs: &OutputFilenames,
835 id: &CrateId) -> Path {
836 let obj_filename = outputs.temp_path(OutputTypeObject);
837 let out_filename = match outputs.single_output_file {
838 Some(ref file) => file.clone(),
840 let out_filename = outputs.path(OutputTypeExe);
841 filename_for_input(sess, crate_type, id, &out_filename)
845 // Make sure the output and obj_filename are both writeable.
846 // Mac, FreeBSD, and Windows system linkers check this already --
847 // however, the Linux linker will happily overwrite a read-only file.
848 // We should be consistent.
849 let obj_is_writeable = is_writeable(&obj_filename);
850 let out_is_writeable = is_writeable(&out_filename);
851 if !out_is_writeable {
852 sess.fatal(format!("output file {} is not writeable -- check its permissions.",
853 out_filename.display()));
855 else if !obj_is_writeable {
856 sess.fatal(format!("object file {} is not writeable -- check its permissions.",
857 obj_filename.display()));
861 session::CrateTypeRlib => {
862 link_rlib(sess, Some(trans), &obj_filename, &out_filename);
864 session::CrateTypeStaticlib => {
865 link_staticlib(sess, &obj_filename, &out_filename);
867 session::CrateTypeExecutable => {
868 link_natively(sess, false, &obj_filename, &out_filename);
870 session::CrateTypeDylib => {
871 link_natively(sess, true, &obj_filename, &out_filename);
880 // An rlib in its current incarnation is essentially a renamed .a file. The
881 // rlib primarily contains the object file of the crate, but it also contains
882 // all of the object files from native libraries. This is done by unzipping
883 // native libraries and inserting all of the contents into this archive.
884 fn link_rlib<'a>(sess: &'a Session,
885 trans: Option<&CrateTranslation>, // None == no metadata/bytecode
887 out_filename: &Path) -> Archive<'a> {
888 let mut a = Archive::create(sess, out_filename, obj_filename);
890 for &(ref l, kind) in sess.cstore.get_used_libraries().borrow().iter() {
892 cstore::NativeStatic => {
893 a.add_native_library(l.as_slice()).unwrap();
895 cstore::NativeFramework | cstore::NativeUnknown => {}
899 // Note that it is important that we add all of our non-object "magical
900 // files" *after* all of the object files in the archive. The reason for
901 // this is as follows:
903 // * When performing LTO, this archive will be modified to remove
904 // obj_filename from above. The reason for this is described below.
906 // * When the system linker looks at an archive, it will attempt to
907 // determine the architecture of the archive in order to see whether its
910 // The algorithm for this detection is: iterate over the files in the
911 // archive. Skip magical SYMDEF names. Interpret the first file as an
912 // object file. Read architecture from the object file.
914 // * As one can probably see, if "metadata" and "foo.bc" were placed
915 // before all of the objects, then the architecture of this archive would
916 // not be correctly inferred once 'foo.o' is removed.
918 // Basically, all this means is that this code should not move above the
922 // Instead of putting the metadata in an object file section, rlibs
923 // contain the metadata in a separate file. We use a temp directory
924 // here so concurrent builds in the same directory don't try to use
925 // the same filename for metadata (stomping over one another)
926 let tmpdir = TempDir::new("rustc").expect("needs a temp dir");
927 let metadata = tmpdir.path().join(METADATA_FILENAME);
928 match fs::File::create(&metadata).write(trans.metadata
932 sess.err(format!("failed to write {}: {}",
933 metadata.display(), e));
934 sess.abort_if_errors();
937 a.add_file(&metadata, false);
938 remove(sess, &metadata);
940 // For LTO purposes, the bytecode of this library is also inserted
942 let bc = obj_filename.with_extension("bc");
943 let bc_deflated = obj_filename.with_extension("bc.deflate");
944 match fs::File::open(&bc).read_to_end().and_then(|data| {
945 fs::File::create(&bc_deflated).write(flate::deflate_bytes(data).as_slice())
949 sess.err(format!("failed to compress bytecode: {}", e));
950 sess.abort_if_errors()
953 a.add_file(&bc_deflated, false);
954 remove(sess, &bc_deflated);
955 if !sess.opts.cg.save_temps &&
956 !sess.opts.output_types.contains(&OutputTypeBitcode) {
960 // After adding all files to the archive, we need to update the
961 // symbol table of the archive. This currently dies on OSX (see
962 // #11162), and isn't necessary there anyway
963 match sess.targ_cfg.os {
965 _ => { a.update_symbols(); }
974 // Create a static archive
976 // This is essentially the same thing as an rlib, but it also involves adding
977 // all of the upstream crates' objects into the archive. This will slurp in
978 // all of the native libraries of upstream dependencies as well.
980 // Additionally, there's no way for us to link dynamic libraries, so we warn
981 // about all dynamic library dependencies that they're not linked in.
983 // There's no need to include metadata in a static archive, so ensure to not
984 // link in the metadata object file (and also don't prepare the archive with a
986 fn link_staticlib(sess: &Session, obj_filename: &Path, out_filename: &Path) {
987 let mut a = link_rlib(sess, None, obj_filename, out_filename);
988 a.add_native_library("morestack").unwrap();
989 a.add_native_library("compiler-rt").unwrap();
991 let crates = sess.cstore.get_used_crates(cstore::RequireStatic);
992 for &(cnum, ref path) in crates.iter() {
993 let name = sess.cstore.get_crate_data(cnum).name.clone();
994 let p = match *path {
995 Some(ref p) => p.clone(), None => {
996 sess.err(format!("could not find rlib for: `{}`", name));
1000 a.add_rlib(&p, name, sess.lto()).unwrap();
1001 let native_libs = csearch::get_native_libraries(&sess.cstore, cnum);
1002 for &(kind, ref lib) in native_libs.iter() {
1003 let name = match kind {
1004 cstore::NativeStatic => "static library",
1005 cstore::NativeUnknown => "library",
1006 cstore::NativeFramework => "framework",
1008 sess.warn(format!("unlinked native {}: {}", name, *lib));
1013 // Create a dynamic library or executable
1015 // This will invoke the system linker/cc to create the resulting file. This
1016 // links to all upstream files as well.
1017 fn link_natively(sess: &Session, dylib: bool, obj_filename: &Path,
1018 out_filename: &Path) {
1019 let tmpdir = TempDir::new("rustc").expect("needs a temp dir");
1020 // The invocations of cc share some flags across platforms
1021 let cc_prog = get_cc_prog(sess);
1022 let mut cc_args = sess.targ_cfg.target_strs.cc_args.clone();
1023 cc_args.push_all_move(link_args(sess, dylib, tmpdir.path(),
1024 obj_filename, out_filename));
1025 if (sess.opts.debugging_opts & session::PRINT_LINK_ARGS) != 0 {
1026 println!("{} link args: '{}'", cc_prog, cc_args.connect("' '"));
1029 // May have not found libraries in the right formats.
1030 sess.abort_if_errors();
1032 // Invoke the system linker
1033 debug!("{} {}", cc_prog, cc_args.connect(" "));
1034 let prog = time(sess.time_passes(), "running linker", (), |()|
1035 Process::output(cc_prog, cc_args.as_slice()));
1038 if !prog.status.success() {
1039 sess.err(format!("linking with `{}` failed: {}", cc_prog, prog.status));
1040 sess.note(format!("{} arguments: '{}'", cc_prog, cc_args.connect("' '")));
1041 sess.note(str::from_utf8_owned(prog.error + prog.output).unwrap());
1042 sess.abort_if_errors();
1046 sess.err(format!("could not exec the linker `{}`: {}", cc_prog, e));
1047 sess.abort_if_errors();
1052 // On OSX, debuggers need this utility to get run to do some munging of
1054 if sess.targ_cfg.os == abi::OsMacos && (sess.opts.debuginfo != NoDebugInfo) {
1055 // FIXME (#9639): This needs to handle non-utf8 paths
1056 match Process::status("dsymutil",
1057 [out_filename.as_str().unwrap().to_owned()]) {
1060 sess.err(format!("failed to run dsymutil: {}", e));
1061 sess.abort_if_errors();
1067 fn link_args(sess: &Session,
1070 obj_filename: &Path,
1071 out_filename: &Path) -> Vec<~str> {
1073 // The default library location, we need this to find the runtime.
1074 // The location of crates will be determined as needed.
1075 // FIXME (#9639): This needs to handle non-utf8 paths
1076 let lib_path = sess.filesearch().get_target_lib_path();
1077 let stage: ~str = ~"-L" + lib_path.as_str().unwrap();
1079 let mut args = vec!(stage);
1081 // FIXME (#9639): This needs to handle non-utf8 paths
1083 ~"-o", out_filename.as_str().unwrap().to_owned(),
1084 obj_filename.as_str().unwrap().to_owned()]);
1086 // Stack growth requires statically linking a __morestack function. Note
1087 // that this is listed *before* all other libraries, even though it may be
1088 // used to resolve symbols in other libraries. The only case that this
1089 // wouldn't be pulled in by the object file is if the object file had no
1092 // If we're building an executable, there must be at least one function (the
1093 // main function), and if we're building a dylib then we don't need it for
1094 // later libraries because they're all dylibs (not rlibs).
1096 // I'm honestly not entirely sure why this needs to come first. Apparently
1097 // the --as-needed flag above sometimes strips out libstd from the command
1098 // line, but inserting this farther to the left makes the
1099 // "rust_stack_exhausted" symbol an outstanding undefined symbol, which
1100 // flags libstd as a required library (or whatever provides the symbol).
1101 args.push(~"-lmorestack");
1103 // When linking a dynamic library, we put the metadata into a section of the
1104 // executable. This metadata is in a separate object file from the main
1105 // object file, so we link that in here.
1107 let metadata = obj_filename.with_extension("metadata.o");
1108 args.push(metadata.as_str().unwrap().to_owned());
1111 // We want to prevent the compiler from accidentally leaking in any system
1112 // libraries, so we explicitly ask gcc to not link to any libraries by
1113 // default. Note that this does not happen for windows because windows pulls
1114 // in some large number of libraries and I couldn't quite figure out which
1115 // subset we wanted.
1117 // FIXME(#11937) we should invoke the system linker directly
1118 if sess.targ_cfg.os != abi::OsWin32 {
1119 args.push(~"-nodefaultlibs");
1122 if sess.targ_cfg.os == abi::OsLinux {
1123 // GNU-style linkers will use this to omit linking to libraries which
1124 // don't actually fulfill any relocations, but only for libraries which
1125 // follow this flag. Thus, use it before specifying libraries to link to.
1126 args.push(~"-Wl,--as-needed");
1128 // GNU-style linkers support optimization with -O. --gc-sections
1129 // removes metadata and potentially other useful things, so don't
1130 // include it. GNU ld doesn't need a numeric argument, but other linkers
1132 if sess.opts.optimize == session::Default ||
1133 sess.opts.optimize == session::Aggressive {
1134 args.push(~"-Wl,-O1");
1138 if sess.targ_cfg.os == abi::OsWin32 {
1139 // Make sure that we link to the dynamic libgcc, otherwise cross-module
1140 // DWARF stack unwinding will not work.
1141 // This behavior may be overridden by --link-args "-static-libgcc"
1142 args.push(~"-shared-libgcc");
1144 // And here, we see obscure linker flags #45. On windows, it has been
1145 // found to be necessary to have this flag to compile liblibc.
1147 // First a bit of background. On Windows, the file format is not ELF,
1148 // but COFF (at least according to LLVM). COFF doesn't officially allow
1149 // for section names over 8 characters, apparently. Our metadata
1150 // section, ".note.rustc", you'll note is over 8 characters.
1152 // On more recent versions of gcc on mingw, apparently the section name
1153 // is *not* truncated, but rather stored elsewhere in a separate lookup
1154 // table. On older versions of gcc, they apparently always truncated the
1155 // section names (at least in some cases). Truncating the section name
1156 // actually creates "invalid" objects [1] [2], but only for some
1157 // introspection tools, not in terms of whether it can be loaded.
1159 // Long story shory, passing this flag forces the linker to *not*
1160 // truncate section names (so we can find the metadata section after
1161 // it's compiled). The real kicker is that rust compiled just fine on
1162 // windows for quite a long time *without* this flag, so I have no idea
1163 // why it suddenly started failing for liblibc. Regardless, we
1164 // definitely don't want section name truncation, so we're keeping this
1165 // flag for windows.
1167 // [1] - https://sourceware.org/bugzilla/show_bug.cgi?id=13130
1168 // [2] - https://code.google.com/p/go/issues/detail?id=2139
1169 args.push(~"-Wl,--enable-long-section-names");
1172 if sess.targ_cfg.os == abi::OsAndroid {
1173 // Many of the symbols defined in compiler-rt are also defined in libgcc.
1174 // Android linker doesn't like that by default.
1175 args.push(~"-Wl,--allow-multiple-definition");
1178 // Take careful note of the ordering of the arguments we pass to the linker
1179 // here. Linkers will assume that things on the left depend on things to the
1180 // right. Things on the right cannot depend on things on the left. This is
1181 // all formally implemented in terms of resolving symbols (libs on the right
1182 // resolve unknown symbols of libs on the left, but not vice versa).
1184 // For this reason, we have organized the arguments we pass to the linker as
1187 // 1. The local object that LLVM just generated
1188 // 2. Upstream rust libraries
1189 // 3. Local native libraries
1190 // 4. Upstream native libraries
1192 // This is generally fairly natural, but some may expect 2 and 3 to be
1193 // swapped. The reason that all native libraries are put last is that it's
1194 // not recommended for a native library to depend on a symbol from a rust
1195 // crate. If this is the case then a staticlib crate is recommended, solving
1198 // Additionally, it is occasionally the case that upstream rust libraries
1199 // depend on a local native library. In the case of libraries such as
1200 // lua/glfw/etc the name of the library isn't the same across all platforms,
1201 // so only the consumer crate of a library knows the actual name. This means
1202 // that downstream crates will provide the #[link] attribute which upstream
1203 // crates will depend on. Hence local native libraries are after out
1204 // upstream rust crates.
1206 // In theory this means that a symbol in an upstream native library will be
1207 // shadowed by a local native library when it wouldn't have been before, but
1208 // this kind of behavior is pretty platform specific and generally not
1209 // recommended anyway, so I don't think we're shooting ourself in the foot
1211 add_upstream_rust_crates(&mut args, sess, dylib, tmpdir);
1212 add_local_native_libraries(&mut args, sess);
1213 add_upstream_native_libraries(&mut args, sess);
1215 // # Telling the linker what we're doing
1218 // On mac we need to tell the linker to let this library be rpathed
1219 if sess.targ_cfg.os == abi::OsMacos {
1220 args.push(~"-dynamiclib");
1221 args.push(~"-Wl,-dylib");
1222 // FIXME (#9639): This needs to handle non-utf8 paths
1223 if !sess.opts.cg.no_rpath {
1224 args.push(~"-Wl,-install_name,@rpath/" +
1225 out_filename.filename_str().unwrap());
1228 args.push(~"-shared")
1232 if sess.targ_cfg.os == abi::OsFreebsd {
1233 args.push_all([~"-L/usr/local/lib",
1234 ~"-L/usr/local/lib/gcc46",
1235 ~"-L/usr/local/lib/gcc44"]);
1238 // FIXME (#2397): At some point we want to rpath our guesses as to
1239 // where extern libraries might live, based on the
1240 // addl_lib_search_paths
1241 if !sess.opts.cg.no_rpath {
1242 args.push_all(rpath::get_rpath_flags(sess, out_filename).as_slice());
1245 // compiler-rt contains implementations of low-level LLVM helpers. This is
1246 // used to resolve symbols from the object file we just created, as well as
1247 // any system static libraries that may be expecting gcc instead. Most
1248 // symbols in libgcc also appear in compiler-rt.
1250 // This is the end of the command line, so this library is used to resolve
1251 // *all* undefined symbols in all other libraries, and this is intentional.
1252 args.push(~"-lcompiler-rt");
1254 // Finally add all the linker arguments provided on the command line along
1255 // with any #[link_args] attributes found inside the crate
1256 args.push_all(sess.opts.cg.link_args.as_slice());
1257 for arg in sess.cstore.get_used_link_args().borrow().iter() {
1258 args.push(arg.clone());
1263 // # Native library linking
1265 // User-supplied library search paths (-L on the command line). These are
1266 // the same paths used to find Rust crates, so some of them may have been
1267 // added already by the previous crate linking code. This only allows them
1268 // to be found at compile time so it is still entirely up to outside
1269 // forces to make sure that library can be found at runtime.
1271 // Also note that the native libraries linked here are only the ones located
1272 // in the current crate. Upstream crates with native library dependencies
1273 // may have their native library pulled in above.
1274 fn add_local_native_libraries(args: &mut Vec<~str>, sess: &Session) {
1275 for path in sess.opts.addl_lib_search_paths.borrow().iter() {
1276 // FIXME (#9639): This needs to handle non-utf8 paths
1277 args.push("-L" + path.as_str().unwrap().to_owned());
1280 let rustpath = filesearch::rust_path();
1281 for path in rustpath.iter() {
1282 // FIXME (#9639): This needs to handle non-utf8 paths
1283 args.push("-L" + path.as_str().unwrap().to_owned());
1286 for &(ref l, kind) in sess.cstore.get_used_libraries().borrow().iter() {
1288 cstore::NativeUnknown | cstore::NativeStatic => {
1289 args.push("-l" + *l);
1291 cstore::NativeFramework => {
1292 args.push(~"-framework");
1293 args.push(l.to_owned());
1299 // # Rust Crate linking
1301 // Rust crates are not considered at all when creating an rlib output. All
1302 // dependencies will be linked when producing the final output (instead of
1303 // the intermediate rlib version)
1304 fn add_upstream_rust_crates(args: &mut Vec<~str>, sess: &Session,
1305 dylib: bool, tmpdir: &Path) {
1307 // As a limitation of the current implementation, we require that everything
1308 // must be static or everything must be dynamic. The reasons for this are a
1309 // little subtle, but as with staticlibs and rlibs, the goal is to prevent
1310 // duplicate copies of the same library showing up. For example, a static
1311 // immediate dependency might show up as an upstream dynamic dependency and
1312 // we currently have no way of knowing that. We know that all dynamic
1313 // libraries require dynamic dependencies (see above), so it's satisfactory
1314 // to include either all static libraries or all dynamic libraries.
1316 // With this limitation, we expose a compiler default linkage type and an
1317 // option to reverse that preference. The current behavior looks like:
1319 // * If a dylib is being created, upstream dependencies must be dylibs
1320 // * If nothing else is specified, static linking is preferred
1321 // * If the -C prefer-dynamic flag is given, dynamic linking is preferred
1322 // * If one form of linking fails, the second is also attempted
1323 // * If both forms fail, then we emit an error message
1325 let dynamic = get_deps(&sess.cstore, cstore::RequireDynamic);
1326 let statik = get_deps(&sess.cstore, cstore::RequireStatic);
1327 match (dynamic, statik, sess.opts.cg.prefer_dynamic, dylib) {
1328 (_, Some(deps), false, false) => {
1329 add_static_crates(args, sess, tmpdir, deps)
1332 (None, Some(deps), true, false) => {
1333 // If you opted in to dynamic linking and we decided to emit a
1334 // static output, you should probably be notified of such an event!
1335 sess.warn("dynamic linking was preferred, but dependencies \
1336 could not all be found in an dylib format.");
1337 sess.warn("linking statically instead, using rlibs");
1338 add_static_crates(args, sess, tmpdir, deps)
1341 (Some(deps), _, _, _) => add_dynamic_crates(args, sess, deps),
1343 (None, _, _, true) => {
1344 sess.err("dylib output requested, but some depenencies could not \
1345 be found in the dylib format");
1346 let deps = sess.cstore.get_used_crates(cstore::RequireDynamic);
1347 for (cnum, path) in deps.move_iter() {
1348 if path.is_some() { continue }
1349 let name = sess.cstore.get_crate_data(cnum).name.clone();
1350 sess.note(format!("dylib not found: {}", name));
1354 (None, None, pref, false) => {
1355 let (pref, name) = if pref {
1356 sess.err("dynamic linking is preferred, but dependencies were \
1357 not found in either dylib or rlib format");
1358 (cstore::RequireDynamic, "dylib")
1360 sess.err("dependencies were not all found in either dylib or \
1362 (cstore::RequireStatic, "rlib")
1364 sess.note(format!("dependencies not found in the `{}` format",
1366 for (cnum, path) in sess.cstore.get_used_crates(pref).move_iter() {
1367 if path.is_some() { continue }
1368 let name = sess.cstore.get_crate_data(cnum).name.clone();
1374 // Converts a library file-stem into a cc -l argument
1375 fn unlib(config: &session::Config, stem: &str) -> ~str {
1376 if stem.starts_with("lib") && config.os != abi::OsWin32 {
1377 stem.slice(3, stem.len()).to_owned()
1383 // Attempts to find all dependencies with a certain linkage preference,
1384 // returning `None` if not all libraries could be found with that
1386 fn get_deps(cstore: &cstore::CStore, preference: cstore::LinkagePreference)
1387 -> Option<Vec<(ast::CrateNum, Path)> >
1389 let crates = cstore.get_used_crates(preference);
1390 if crates.iter().all(|&(_, ref p)| p.is_some()) {
1391 Some(crates.move_iter().map(|(a, b)| (a, b.unwrap())).collect())
1397 // Adds the static "rlib" versions of all crates to the command line.
1398 fn add_static_crates(args: &mut Vec<~str>, sess: &Session, tmpdir: &Path,
1399 crates: Vec<(ast::CrateNum, Path)>) {
1400 for (cnum, cratepath) in crates.move_iter() {
1401 // When performing LTO on an executable output, all of the
1402 // bytecode from the upstream libraries has already been
1403 // included in our object file output. We need to modify all of
1404 // the upstream archives to remove their corresponding object
1405 // file to make sure we don't pull the same code in twice.
1407 // We must continue to link to the upstream archives to be sure
1408 // to pull in native static dependencies. As the final caveat,
1409 // on linux it is apparently illegal to link to a blank archive,
1410 // so if an archive no longer has any object files in it after
1411 // we remove `lib.o`, then don't link against it at all.
1413 // If we're not doing LTO, then our job is simply to just link
1414 // against the archive.
1416 let name = sess.cstore.get_crate_data(cnum).name.clone();
1417 time(sess.time_passes(), format!("altering {}.rlib", name),
1419 let dst = tmpdir.join(cratepath.filename().unwrap());
1420 match fs::copy(&cratepath, &dst) {
1423 sess.err(format!("failed to copy {} to {}: {}",
1424 cratepath.display(),
1427 sess.abort_if_errors();
1430 let dst_str = dst.as_str().unwrap().to_owned();
1431 let mut archive = Archive::open(sess, dst);
1432 archive.remove_file(format!("{}.o", name));
1433 let files = archive.files();
1434 if files.iter().any(|s| s.ends_with(".o")) {
1439 args.push(cratepath.as_str().unwrap().to_owned());
1444 // Same thing as above, but for dynamic crates instead of static crates.
1445 fn add_dynamic_crates(args: &mut Vec<~str>, sess: &Session,
1446 crates: Vec<(ast::CrateNum, Path)> ) {
1447 // If we're performing LTO, then it should have been previously required
1448 // that all upstream rust dependencies were available in an rlib format.
1449 assert!(!sess.lto());
1451 for (_, cratepath) in crates.move_iter() {
1452 // Just need to tell the linker about where the library lives and
1454 let dir = cratepath.dirname_str().unwrap();
1455 if !dir.is_empty() { args.push("-L" + dir); }
1456 let libarg = unlib(&sess.targ_cfg, cratepath.filestem_str().unwrap());
1457 args.push("-l" + libarg);
1462 // Link in all of our upstream crates' native dependencies. Remember that
1463 // all of these upstream native depenencies are all non-static
1464 // dependencies. We've got two cases then:
1466 // 1. The upstream crate is an rlib. In this case we *must* link in the
1467 // native dependency because the rlib is just an archive.
1469 // 2. The upstream crate is a dylib. In order to use the dylib, we have to
1470 // have the dependency present on the system somewhere. Thus, we don't
1471 // gain a whole lot from not linking in the dynamic dependency to this
1474 // The use case for this is a little subtle. In theory the native
1475 // dependencies of a crate a purely an implementation detail of the crate
1476 // itself, but the problem arises with generic and inlined functions. If a
1477 // generic function calls a native function, then the generic function must
1478 // be instantiated in the target crate, meaning that the native symbol must
1479 // also be resolved in the target crate.
1480 fn add_upstream_native_libraries(args: &mut Vec<~str>, sess: &Session) {
1481 let cstore = &sess.cstore;
1482 cstore.iter_crate_data(|cnum, _| {
1483 let libs = csearch::get_native_libraries(cstore, cnum);
1484 for &(kind, ref lib) in libs.iter() {
1486 cstore::NativeUnknown => args.push("-l" + *lib),
1487 cstore::NativeFramework => {
1488 args.push(~"-framework");
1489 args.push(lib.to_owned());
1491 cstore::NativeStatic => {
1492 sess.bug("statics shouldn't be propagated");