1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 use super::archive
::{ArchiveBuilder, ArchiveConfig}
;
12 use super::linker
::{Linker, GnuLinker, MsvcLinker}
;
13 use super::rpath
::RPathConfig
;
18 use session
::config
::NoDebugInfo
;
19 use session
::config
::{OutputFilenames, Input, OutputTypeBitcode, OutputTypeExe, OutputTypeObject}
;
20 use session
::search_paths
::PathKind
;
22 use metadata
::common
::LinkMeta
;
23 use metadata
::filesearch
::FileDoesntMatch
;
24 use metadata
::loader
::METADATA_FILENAME
;
25 use metadata
::{encoder, cstore, filesearch, csearch, creader}
;
26 use middle
::ty
::{self, Ty}
;
27 use rustc
::ast_map
::{PathElem, PathElems, PathName}
;
28 use trans
::{CrateContext, CrateTranslation, gensym_name}
;
29 use util
::common
::time
;
30 use util
::sha2
::{Digest, Sha256}
;
31 use util
::fs
::fix_windows_verbatim_for_gcc
;
32 use rustc_back
::tempdir
::TempDir
;
35 use std
::ffi
::OsString
;
36 use std
::fs
::{self, PathExt}
;
37 use std
::io
::{self, Read, Write}
;
39 use std
::path
::{Path, PathBuf}
;
40 use std
::process
::Command
;
43 use serialize
::hex
::ToHex
;
45 use syntax
::attr
::AttrMetaMethods
;
46 use syntax
::codemap
::Span
;
47 use syntax
::parse
::token
;
49 // RLIB LLVM-BYTECODE OBJECT LAYOUT
52 // 0..10 "RUST_OBJECT" encoded in ASCII
53 // 11..14 format version as little-endian u32
54 // 15..22 size in bytes of deflate compressed LLVM bitcode as
56 // 23.. compressed LLVM bitcode
58 // This is the "magic number" expected at the beginning of a LLVM bytecode
60 pub const RLIB_BYTECODE_OBJECT_MAGIC
: &'
static [u8] = b
"RUST_OBJECT";
62 // The version number this compiler will write to bytecode objects in rlibs
63 pub const RLIB_BYTECODE_OBJECT_VERSION
: u32 = 1;
65 // The offset in bytes the bytecode object format version number can be found at
66 pub const RLIB_BYTECODE_OBJECT_VERSION_OFFSET
: usize = 11;
68 // The offset in bytes the size of the compressed bytecode can be found at in
70 pub const RLIB_BYTECODE_OBJECT_V1_DATASIZE_OFFSET
: usize =
71 RLIB_BYTECODE_OBJECT_VERSION_OFFSET
+ 4;
73 // The offset in bytes the compressed LLVM bytecode can be found at in format
75 pub const RLIB_BYTECODE_OBJECT_V1_DATA_OFFSET
: usize =
76 RLIB_BYTECODE_OBJECT_V1_DATASIZE_OFFSET
+ 8;
80 * Name mangling and its relationship to metadata. This is complex. Read
83 * The semantic model of Rust linkage is, broadly, that "there's no global
84 * namespace" between crates. Our aim is to preserve the illusion of this
85 * model despite the fact that it's not *quite* possible to implement on
86 * modern linkers. We initially didn't use system linkers at all, but have
87 * been convinced of their utility.
89 * There are a few issues to handle:
91 * - Linkers operate on a flat namespace, so we have to flatten names.
92 * We do this using the C++ namespace-mangling technique. Foo::bar
95 * - Symbols with the same name but different types need to get different
96 * linkage-names. We do this by hashing a string-encoding of the type into
97 * a fixed-size (currently 16-byte hex) cryptographic hash function (CHF:
98 * we use SHA256) to "prevent collisions". This is not airtight but 16 hex
99 * digits on uniform probability means you're going to need 2**32 same-name
100 * symbols in the same process before you're even hitting birthday-paradox
101 * collision probability.
103 * - Symbols in different crates but with same names "within" the crate need
104 * to get different linkage-names.
106 * - The hash shown in the filename needs to be predictable and stable for
107 * build tooling integration. It also needs to be using a hash function
108 * which is easy to use from Python, make, etc.
110 * So here is what we do:
112 * - Consider the package id; every crate has one (specified with crate_id
113 * attribute). If a package id isn't provided explicitly, we infer a
114 * versionless one from the output name. The version will end up being 0.0
115 * in this case. CNAME and CVERS are taken from this package id. For
116 * example, github.com/mozilla/CNAME#CVERS.
118 * - Define CMH as SHA256(crateid).
120 * - Define CMH8 as the first 8 characters of CMH.
122 * - Compile our crate to lib CNAME-CMH8-CVERS.so
124 * - Define STH(sym) as SHA256(CMH, type_str(sym))
126 * - Suffix a mangled sym with ::STH@CVERS, so that it is unique in the
127 * name, non-name metadata, and type sense, and versioned in the way
128 * system linkers understand.
131 pub fn find_crate_name(sess
: Option
<&Session
>,
132 attrs
: &[ast
::Attribute
],
133 input
: &Input
) -> String
{
134 let validate
= |s
: String
, span
: Option
<Span
>| {
135 creader
::validate_crate_name(sess
, &s
[..], span
);
139 // Look in attributes 100% of the time to make sure the attribute is marked
140 // as used. After doing this, however, we still prioritize a crate name from
141 // the command line over one found in the #[crate_name] attribute. If we
142 // find both we ensure that they're the same later on as well.
143 let attr_crate_name
= attrs
.iter().find(|at
| at
.check_name("crate_name"))
144 .and_then(|at
| at
.value_str().map(|s
| (at
, s
)));
146 if let Some(sess
) = sess
{
147 if let Some(ref s
) = sess
.opts
.crate_name
{
148 if let Some((attr
, ref name
)) = attr_crate_name
{
150 let msg
= format
!("--crate-name and #[crate_name] are \
151 required to match, but `{}` != `{}`",
153 sess
.span_err(attr
.span
, &msg
[..]);
156 return validate(s
.clone(), None
);
160 if let Some((attr
, s
)) = attr_crate_name
{
161 return validate(s
.to_string(), Some(attr
.span
));
163 if let Input
::File(ref path
) = *input
{
164 if let Some(s
) = path
.file_stem().and_then(|s
| s
.to_str()) {
165 if s
.starts_with("-") {
166 let msg
= format
!("crate names cannot start with a `-`, but \
167 `{}` has a leading hyphen", s
);
168 if let Some(sess
) = sess
{
172 return validate(s
.replace("-", "_"), None
);
177 "rust_out".to_string()
180 pub fn build_link_meta(sess
: &Session
, krate
: &ast
::Crate
,
181 name
: String
) -> LinkMeta
{
184 crate_hash
: Svh
::calculate(&sess
.opts
.cg
.metadata
, krate
),
190 fn truncated_hash_result(symbol_hasher
: &mut Sha256
) -> String
{
191 let output
= symbol_hasher
.result_bytes();
192 // 64 bits should be enough to avoid collisions.
193 output
[.. 8].to_hex().to_string()
197 // This calculates STH for a symbol, as defined above
198 fn symbol_hash
<'tcx
>(tcx
: &ty
::ctxt
<'tcx
>,
199 symbol_hasher
: &mut Sha256
,
201 link_meta
: &LinkMeta
)
203 // NB: do *not* use abbrevs here as we want the symbol names
204 // to be independent of one another in the crate.
206 symbol_hasher
.reset();
207 symbol_hasher
.input_str(&link_meta
.crate_name
);
208 symbol_hasher
.input_str("-");
209 symbol_hasher
.input_str(link_meta
.crate_hash
.as_str());
210 for meta
in tcx
.sess
.crate_metadata
.borrow().iter() {
211 symbol_hasher
.input_str(&meta
[..]);
213 symbol_hasher
.input_str("-");
214 symbol_hasher
.input_str(&encoder
::encoded_ty(tcx
, t
));
215 // Prefix with 'h' so that it never blends into adjacent digits
216 let mut hash
= String
::from("h");
217 hash
.push_str(&truncated_hash_result(symbol_hasher
));
221 fn get_symbol_hash
<'a
, 'tcx
>(ccx
: &CrateContext
<'a
, 'tcx
>, t
: Ty
<'tcx
>) -> String
{
222 match ccx
.type_hashcodes().borrow().get(&t
) {
223 Some(h
) => return h
.to_string(),
227 let mut symbol_hasher
= ccx
.symbol_hasher().borrow_mut();
228 let hash
= symbol_hash(ccx
.tcx(), &mut *symbol_hasher
, t
, ccx
.link_meta());
229 ccx
.type_hashcodes().borrow_mut().insert(t
, hash
.clone());
234 // Name sanitation. LLVM will happily accept identifiers with weird names, but
236 // gas accepts the following characters in symbols: a-z, A-Z, 0-9, ., _, $
237 pub fn sanitize(s
: &str) -> String
{
238 let mut result
= String
::new();
241 // Escape these with $ sequences
242 '@'
=> result
.push_str("$SP$"),
243 '
*'
=> result
.push_str("$BP$"),
244 '
&'
=> result
.push_str("$RF$"),
245 '
<'
=> result
.push_str("$LT$"),
246 '
>'
=> result
.push_str("$GT$"),
247 '
('
=> result
.push_str("$LP$"),
248 '
)'
=> result
.push_str("$RP$"),
249 '
,'
=> result
.push_str("$C$"),
251 // '.' doesn't occur in types and functions, so reuse it
253 '
-'
| '
:'
=> result
.push('
.'
),
255 // These are legal symbols
259 | '_'
| '
.'
| '$'
=> result
.push(c
),
263 for c
in c
.escape_unicode().skip(1) {
266 '
}'
=> result
.push('$'
),
274 // Underscore-qualify anything that didn't start as an ident.
275 if !result
.is_empty() &&
276 result
.as_bytes()[0] != '_'
as u8 &&
277 ! (result
.as_bytes()[0] as char).is_xid_start() {
278 return format
!("_{}", &result
[..]);
284 pub fn mangle
<PI
: Iterator
<Item
=PathElem
>>(path
: PI
,
285 hash
: Option
<&str>) -> String
{
286 // Follow C++ namespace-mangling style, see
287 // http://en.wikipedia.org/wiki/Name_mangling for more info.
289 // It turns out that on OSX you can actually have arbitrary symbols in
290 // function names (at least when given to LLVM), but this is not possible
291 // when using unix's linker. Perhaps one day when we just use a linker from LLVM
292 // we won't need to do this name mangling. The problem with name mangling is
293 // that it seriously limits the available characters. For example we can't
294 // have things like &T in symbol names when one would theoretically
295 // want them for things like impls of traits on that type.
297 // To be able to work on all platforms and get *some* reasonable output, we
298 // use C++ name-mangling.
300 let mut n
= String
::from("_ZN"); // _Z == Begin name-sequence, N == nested
302 fn push(n
: &mut String
, s
: &str) {
303 let sani
= sanitize(s
);
304 n
.push_str(&format
!("{}{}", sani
.len(), sani
));
307 // First, connect each component with <len, name> pairs.
309 push(&mut n
, &e
.name().as_str())
313 Some(s
) => push(&mut n
, s
),
317 n
.push('E'
); // End name-sequence.
321 pub fn exported_name(path
: PathElems
, hash
: &str) -> String
{
322 mangle(path
, Some(hash
))
325 pub fn mangle_exported_name
<'a
, 'tcx
>(ccx
: &CrateContext
<'a
, 'tcx
>, path
: PathElems
,
326 t
: Ty
<'tcx
>, id
: ast
::NodeId
) -> String
{
327 let mut hash
= get_symbol_hash(ccx
, t
);
329 // Paths can be completely identical for different nodes,
330 // e.g. `fn foo() { { fn a() {} } { fn a() {} } }`, so we
331 // generate unique characters from the node id. For now
332 // hopefully 3 characters is enough to avoid collisions.
333 const EXTRA_CHARS
: &'
static str =
334 "abcdefghijklmnopqrstuvwxyz\
335 ABCDEFGHIJKLMNOPQRSTUVWXYZ\
337 let id
= id
as usize;
338 let extra1
= id
% EXTRA_CHARS
.len();
339 let id
= id
/ EXTRA_CHARS
.len();
340 let extra2
= id
% EXTRA_CHARS
.len();
341 let id
= id
/ EXTRA_CHARS
.len();
342 let extra3
= id
% EXTRA_CHARS
.len();
343 hash
.push(EXTRA_CHARS
.as_bytes()[extra1
] as char);
344 hash
.push(EXTRA_CHARS
.as_bytes()[extra2
] as char);
345 hash
.push(EXTRA_CHARS
.as_bytes()[extra3
] as char);
347 exported_name(path
, &hash
[..])
350 pub fn mangle_internal_name_by_type_and_seq
<'a
, 'tcx
>(ccx
: &CrateContext
<'a
, 'tcx
>,
352 name
: &str) -> String
{
353 let path
= [PathName(token
::intern(&t
.to_string())),
355 let hash
= get_symbol_hash(ccx
, t
);
356 mangle(path
.iter().cloned(), Some(&hash
[..]))
359 pub fn mangle_internal_name_by_path_and_seq(path
: PathElems
, flav
: &str) -> String
{
360 mangle(path
.chain(Some(gensym_name(flav
))), None
)
363 pub fn get_linker(sess
: &Session
) -> (String
, Command
) {
364 if let Some(ref linker
) = sess
.opts
.cg
.linker
{
365 (linker
.clone(), Command
::new(linker
))
366 } else if sess
.target
.target
.options
.is_like_msvc
{
367 ("link.exe".to_string(), msvc
::link_exe_cmd(sess
))
369 (sess
.target
.target
.options
.linker
.clone(),
370 Command
::new(&sess
.target
.target
.options
.linker
))
374 pub fn get_ar_prog(sess
: &Session
) -> String
{
375 sess
.opts
.cg
.ar
.clone().unwrap_or_else(|| {
376 sess
.target
.target
.options
.ar
.clone()
380 fn command_path(sess
: &Session
) -> OsString
{
381 // The compiler's sysroot often has some bundled tools, so add it to the
382 // PATH for the child.
383 let mut new_path
= sess
.host_filesearch(PathKind
::All
)
384 .get_tools_search_paths();
385 if let Some(path
) = env
::var_os("PATH") {
386 new_path
.extend(env
::split_paths(&path
));
388 env
::join_paths(new_path
).unwrap()
391 pub fn remove(sess
: &Session
, path
: &Path
) {
392 match fs
::remove_file(path
) {
395 sess
.err(&format
!("failed to remove {}: {}",
402 /// Perform the linkage portion of the compilation phase. This will generate all
403 /// of the requested outputs for this compilation session.
404 pub fn link_binary(sess
: &Session
,
405 trans
: &CrateTranslation
,
406 outputs
: &OutputFilenames
,
407 crate_name
: &str) -> Vec
<PathBuf
> {
408 let mut out_filenames
= Vec
::new();
409 for &crate_type
in sess
.crate_types
.borrow().iter() {
410 if invalid_output_for_target(sess
, crate_type
) {
411 sess
.bug(&format
!("invalid output type `{:?}` for target os `{}`",
412 crate_type
, sess
.opts
.target_triple
));
414 let out_file
= link_binary_output(sess
, trans
, crate_type
, outputs
,
416 out_filenames
.push(out_file
);
419 // Remove the temporary object file and metadata if we aren't saving temps
420 if !sess
.opts
.cg
.save_temps
{
421 for obj
in object_filenames(sess
, outputs
) {
424 remove(sess
, &outputs
.with_extension("metadata.o"));
431 /// Returns default crate type for target
433 /// Default crate type is used when crate type isn't provided neither
434 /// through cmd line arguments nor through crate attributes
436 /// It is CrateTypeExecutable for all platforms but iOS as there is no
437 /// way to run iOS binaries anyway without jailbreaking and
438 /// interaction with Rust code through static library is the only
440 pub fn default_output_for_target(sess
: &Session
) -> config
::CrateType
{
441 if !sess
.target
.target
.options
.executables
{
442 config
::CrateTypeStaticlib
444 config
::CrateTypeExecutable
448 /// Checks if target supports crate_type as output
449 pub fn invalid_output_for_target(sess
: &Session
,
450 crate_type
: config
::CrateType
) -> bool
{
451 match (sess
.target
.target
.options
.dynamic_linking
,
452 sess
.target
.target
.options
.executables
, crate_type
) {
453 (false, _
, config
::CrateTypeDylib
) => true,
454 (_
, false, config
::CrateTypeExecutable
) => true,
459 fn is_writeable(p
: &Path
) -> bool
{
462 Ok(m
) => !m
.permissions().readonly()
466 pub fn filename_for_input(sess
: &Session
,
467 crate_type
: config
::CrateType
,
469 outputs
: &OutputFilenames
) -> PathBuf
{
470 let libname
= format
!("{}{}", crate_name
, sess
.opts
.cg
.extra_filename
);
472 config
::CrateTypeRlib
=> {
473 outputs
.out_directory
.join(&format
!("lib{}.rlib", libname
))
475 config
::CrateTypeDylib
=> {
476 let (prefix
, suffix
) = (&sess
.target
.target
.options
.dll_prefix
,
477 &sess
.target
.target
.options
.dll_suffix
);
478 outputs
.out_directory
.join(&format
!("{}{}{}", prefix
, libname
,
481 config
::CrateTypeStaticlib
=> {
482 outputs
.out_directory
.join(&format
!("lib{}.a", libname
))
484 config
::CrateTypeExecutable
=> {
485 let suffix
= &sess
.target
.target
.options
.exe_suffix
;
486 let out_filename
= outputs
.path(OutputTypeExe
);
487 if suffix
.is_empty() {
488 out_filename
.to_path_buf()
490 out_filename
.with_extension(&suffix
[1..])
496 fn link_binary_output(sess
: &Session
,
497 trans
: &CrateTranslation
,
498 crate_type
: config
::CrateType
,
499 outputs
: &OutputFilenames
,
500 crate_name
: &str) -> PathBuf
{
501 let objects
= object_filenames(sess
, outputs
);
502 let out_filename
= match outputs
.single_output_file
{
503 Some(ref file
) => file
.clone(),
504 None
=> filename_for_input(sess
, crate_type
, crate_name
, outputs
),
507 // Make sure files are writeable. Mac, FreeBSD, and Windows system linkers
508 // check this already -- however, the Linux linker will happily overwrite a
509 // read-only file. We should be consistent.
510 for file
in objects
.iter().chain(Some(&out_filename
)) {
511 if !is_writeable(file
) {
512 sess
.fatal(&format
!("output file {} is not writeable -- check its \
513 permissions", file
.display()));
517 let tmpdir
= TempDir
::new("rustc").ok().expect("needs a temp dir");
519 config
::CrateTypeRlib
=> {
520 link_rlib(sess
, Some(trans
), &objects
, &out_filename
,
521 tmpdir
.path()).build();
523 config
::CrateTypeStaticlib
=> {
524 link_staticlib(sess
, &objects
, &out_filename
, tmpdir
.path());
526 config
::CrateTypeExecutable
=> {
527 link_natively(sess
, trans
, false, &objects
, &out_filename
, outputs
,
530 config
::CrateTypeDylib
=> {
531 link_natively(sess
, trans
, true, &objects
, &out_filename
, outputs
,
539 fn object_filenames(sess
: &Session
, outputs
: &OutputFilenames
) -> Vec
<PathBuf
> {
540 (0..sess
.opts
.cg
.codegen_units
).map(|i
| {
541 let ext
= format
!("{}.o", i
);
542 outputs
.temp_path(OutputTypeObject
).with_extension(&ext
)
546 fn archive_search_paths(sess
: &Session
) -> Vec
<PathBuf
> {
547 let mut search
= Vec
::new();
548 sess
.target_filesearch(PathKind
::Native
).for_each_lib_search_path(|path
, _
| {
549 search
.push(path
.to_path_buf());
555 fn archive_config
<'a
>(sess
: &'a Session
,
557 input
: Option
<&Path
>) -> ArchiveConfig
<'a
> {
560 dst
: output
.to_path_buf(),
561 src
: input
.map(|p
| p
.to_path_buf()),
562 lib_search_paths
: archive_search_paths(sess
),
563 ar_prog
: get_ar_prog(sess
),
564 command_path
: command_path(sess
),
570 // An rlib in its current incarnation is essentially a renamed .a file. The
571 // rlib primarily contains the object file of the crate, but it also contains
572 // all of the object files from native libraries. This is done by unzipping
573 // native libraries and inserting all of the contents into this archive.
574 fn link_rlib
<'a
>(sess
: &'a Session
,
575 trans
: Option
<&CrateTranslation
>, // None == no metadata/bytecode
578 tmpdir
: &Path
) -> ArchiveBuilder
<'a
> {
579 info
!("preparing rlib from {:?} to {:?}", objects
, out_filename
);
580 let mut ab
= ArchiveBuilder
::new(archive_config(sess
, out_filename
, None
));
585 for &(ref l
, kind
) in sess
.cstore
.get_used_libraries().borrow().iter() {
587 cstore
::NativeStatic
=> ab
.add_native_library(&l
).unwrap(),
588 cstore
::NativeFramework
| cstore
::NativeUnknown
=> {}
592 // After adding all files to the archive, we need to update the
593 // symbol table of the archive.
596 // For OSX/iOS, we must be careful to update symbols only when adding
597 // object files. We're about to start adding non-object files, so run
598 // `ar` now to process the object files.
599 if sess
.target
.target
.options
.is_like_osx
&& !ab
.using_llvm() {
603 // Note that it is important that we add all of our non-object "magical
604 // files" *after* all of the object files in the archive. The reason for
605 // this is as follows:
607 // * When performing LTO, this archive will be modified to remove
608 // objects from above. The reason for this is described below.
610 // * When the system linker looks at an archive, it will attempt to
611 // determine the architecture of the archive in order to see whether its
614 // The algorithm for this detection is: iterate over the files in the
615 // archive. Skip magical SYMDEF names. Interpret the first file as an
616 // object file. Read architecture from the object file.
618 // * As one can probably see, if "metadata" and "foo.bc" were placed
619 // before all of the objects, then the architecture of this archive would
620 // not be correctly inferred once 'foo.o' is removed.
622 // Basically, all this means is that this code should not move above the
626 // Instead of putting the metadata in an object file section, rlibs
627 // contain the metadata in a separate file. We use a temp directory
628 // here so concurrent builds in the same directory don't try to use
629 // the same filename for metadata (stomping over one another)
630 let metadata
= tmpdir
.join(METADATA_FILENAME
);
631 match fs
::File
::create(&metadata
).and_then(|mut f
| {
632 f
.write_all(&trans
.metadata
)
636 sess
.fatal(&format
!("failed to write {}: {}",
637 metadata
.display(), e
));
640 ab
.add_file(&metadata
);
642 // For LTO purposes, the bytecode of this library is also inserted
643 // into the archive. If codegen_units > 1, we insert each of the
646 // Note that we make sure that the bytecode filename in the
647 // archive is never exactly 16 bytes long by adding a 16 byte
648 // extension to it. This is to work around a bug in LLDB that
649 // would cause it to crash if the name of a file in an archive
650 // was exactly 16 bytes.
651 let bc_filename
= obj
.with_extension("bc");
652 let bc_deflated_filename
= tmpdir
.join({
653 obj
.with_extension("bytecode.deflate").file_name().unwrap()
656 let mut bc_data
= Vec
::new();
657 match fs
::File
::open(&bc_filename
).and_then(|mut f
| {
658 f
.read_to_end(&mut bc_data
)
661 Err(e
) => sess
.fatal(&format
!("failed to read bytecode: {}",
665 let bc_data_deflated
= flate
::deflate_bytes(&bc_data
[..]);
667 let mut bc_file_deflated
= match fs
::File
::create(&bc_deflated_filename
) {
670 sess
.fatal(&format
!("failed to create compressed \
671 bytecode file: {}", e
))
675 match write_rlib_bytecode_object_v1(&mut bc_file_deflated
,
679 sess
.fatal(&format
!("failed to write compressed \
684 ab
.add_file(&bc_deflated_filename
);
686 // See the bottom of back::write::run_passes for an explanation
687 // of when we do and don't keep .0.bc files around.
688 let user_wants_numbered_bitcode
=
689 sess
.opts
.output_types
.contains(&OutputTypeBitcode
) &&
690 sess
.opts
.cg
.codegen_units
> 1;
691 if !sess
.opts
.cg
.save_temps
&& !user_wants_numbered_bitcode
{
692 remove(sess
, &bc_filename
);
696 // After adding all files to the archive, we need to update the
697 // symbol table of the archive. This currently dies on OSX (see
698 // #11162), and isn't necessary there anyway
699 if !sess
.target
.target
.options
.is_like_osx
|| ab
.using_llvm() {
710 fn write_rlib_bytecode_object_v1(writer
: &mut Write
,
711 bc_data_deflated
: &[u8]) -> io
::Result
<()> {
712 let bc_data_deflated_size
: u64 = bc_data_deflated
.len() as u64;
714 try
!(writer
.write_all(RLIB_BYTECODE_OBJECT_MAGIC
));
715 try
!(writer
.write_all(&[1, 0, 0, 0]));
716 try
!(writer
.write_all(&[
717 (bc_data_deflated_size
>> 0) as u8,
718 (bc_data_deflated_size
>> 8) as u8,
719 (bc_data_deflated_size
>> 16) as u8,
720 (bc_data_deflated_size
>> 24) as u8,
721 (bc_data_deflated_size
>> 32) as u8,
722 (bc_data_deflated_size
>> 40) as u8,
723 (bc_data_deflated_size
>> 48) as u8,
724 (bc_data_deflated_size
>> 56) as u8,
726 try
!(writer
.write_all(&bc_data_deflated
));
728 let number_of_bytes_written_so_far
=
729 RLIB_BYTECODE_OBJECT_MAGIC
.len() + // magic id
730 mem
::size_of_val(&RLIB_BYTECODE_OBJECT_VERSION
) + // version
731 mem
::size_of_val(&bc_data_deflated_size
) + // data size field
732 bc_data_deflated_size
as usize; // actual data
734 // If the number of bytes written to the object so far is odd, add a
735 // padding byte to make it even. This works around a crash bug in LLDB
736 // (see issue #15950)
737 if number_of_bytes_written_so_far
% 2 == 1 {
738 try
!(writer
.write_all(&[0]));
744 // Create a static archive
746 // This is essentially the same thing as an rlib, but it also involves adding
747 // all of the upstream crates' objects into the archive. This will slurp in
748 // all of the native libraries of upstream dependencies as well.
750 // Additionally, there's no way for us to link dynamic libraries, so we warn
751 // about all dynamic library dependencies that they're not linked in.
753 // There's no need to include metadata in a static archive, so ensure to not
754 // link in the metadata object file (and also don't prepare the archive with a
756 fn link_staticlib(sess
: &Session
, objects
: &[PathBuf
], out_filename
: &Path
,
758 let mut ab
= link_rlib(sess
, None
, objects
, out_filename
, tempdir
);
759 if sess
.target
.target
.options
.is_like_osx
&& !ab
.using_llvm() {
762 if sess
.target
.target
.options
.morestack
{
763 ab
.add_native_library("morestack").unwrap();
765 if !sess
.target
.target
.options
.no_compiler_rt
{
766 ab
.add_native_library("compiler-rt").unwrap();
769 let crates
= sess
.cstore
.get_used_crates(cstore
::RequireStatic
);
770 let mut all_native_libs
= vec
![];
772 for &(cnum
, ref path
) in &crates
{
773 let ref name
= sess
.cstore
.get_crate_data(cnum
).name
;
774 let p
= match *path
{
775 Some(ref p
) => p
.clone(), None
=> {
776 sess
.err(&format
!("could not find rlib for: `{}`",
781 ab
.add_rlib(&p
, &name
[..], sess
.lto()).unwrap();
783 let native_libs
= csearch
::get_native_libraries(&sess
.cstore
, cnum
);
784 all_native_libs
.extend(native_libs
);
790 if !all_native_libs
.is_empty() {
791 sess
.note("link against the following native artifacts when linking against \
792 this static library");
793 sess
.note("the order and any duplication can be significant on some platforms, \
794 and so may need to be preserved");
797 for &(kind
, ref lib
) in &all_native_libs
{
798 let name
= match kind
{
799 cstore
::NativeStatic
=> "static library",
800 cstore
::NativeUnknown
=> "library",
801 cstore
::NativeFramework
=> "framework",
803 sess
.note(&format
!("{}: {}", name
, *lib
));
807 // Create a dynamic library or executable
809 // This will invoke the system linker/cc to create the resulting file. This
810 // links to all upstream files as well.
811 fn link_natively(sess
: &Session
, trans
: &CrateTranslation
, dylib
: bool
,
812 objects
: &[PathBuf
], out_filename
: &Path
,
813 outputs
: &OutputFilenames
,
815 info
!("preparing dylib? ({}) from {:?} to {:?}", dylib
, objects
,
818 // The invocations of cc share some flags across platforms
819 let (pname
, mut cmd
) = get_linker(sess
);
820 cmd
.env("PATH", command_path(sess
));
822 let root
= sess
.target_filesearch(PathKind
::Native
).get_lib_path();
823 cmd
.args(&sess
.target
.target
.options
.pre_link_args
);
824 for obj
in &sess
.target
.target
.options
.pre_link_objects
{
825 cmd
.arg(root
.join(obj
));
829 let mut linker
= if sess
.target
.target
.options
.is_like_msvc
{
830 Box
::new(MsvcLinker { cmd: &mut cmd, sess: &sess }
) as Box
<Linker
>
832 Box
::new(GnuLinker { cmd: &mut cmd, sess: &sess }
) as Box
<Linker
>
834 link_args(&mut *linker
, sess
, dylib
, tmpdir
,
835 trans
, objects
, out_filename
, outputs
);
836 if !sess
.target
.target
.options
.no_compiler_rt
{
837 linker
.link_staticlib("compiler-rt");
840 for obj
in &sess
.target
.target
.options
.post_link_objects
{
841 cmd
.arg(root
.join(obj
));
843 cmd
.args(&sess
.target
.target
.options
.post_link_args
);
845 if sess
.opts
.debugging_opts
.print_link_args
{
846 println
!("{:?}", &cmd
);
849 // May have not found libraries in the right formats.
850 sess
.abort_if_errors();
852 // Invoke the system linker
854 let prog
= time(sess
.time_passes(), "running linker", (), |()| cmd
.output());
857 if !prog
.status
.success() {
858 sess
.err(&format
!("linking with `{}` failed: {}",
861 sess
.note(&format
!("{:?}", &cmd
));
862 let mut output
= prog
.stderr
.clone();
863 output
.push_all(&prog
.stdout
);
864 sess
.note(str::from_utf8(&output
[..]).unwrap());
865 sess
.abort_if_errors();
867 info
!("linker stderr:\n{}", String
::from_utf8(prog
.stderr
).unwrap());
868 info
!("linker stdout:\n{}", String
::from_utf8(prog
.stdout
).unwrap());
871 sess
.fatal(&format
!("could not exec the linker `{}`: {}", pname
, e
));
876 // On OSX, debuggers need this utility to get run to do some munging of
878 if sess
.target
.target
.options
.is_like_osx
&& sess
.opts
.debuginfo
!= NoDebugInfo
{
879 match Command
::new("dsymutil").arg(out_filename
).output() {
881 Err(e
) => sess
.fatal(&format
!("failed to run dsymutil: {}", e
)),
886 fn link_args(cmd
: &mut Linker
,
890 trans
: &CrateTranslation
,
893 outputs
: &OutputFilenames
) {
895 // The default library location, we need this to find the runtime.
896 // The location of crates will be determined as needed.
897 let lib_path
= sess
.target_filesearch(PathKind
::All
).get_lib_path();
900 let t
= &sess
.target
.target
;
902 cmd
.include_path(&fix_windows_verbatim_for_gcc(&lib_path
));
906 cmd
.output_filename(out_filename
);
908 // Stack growth requires statically linking a __morestack function. Note
909 // that this is listed *before* all other libraries. Due to the usage of the
910 // --as-needed flag below, the standard library may only be useful for its
911 // rust_stack_exhausted function. In this case, we must ensure that the
912 // libmorestack.a file appears *before* the standard library (so we put it
913 // at the very front).
915 // Most of the time this is sufficient, except for when LLVM gets super
916 // clever. If, for example, we have a main function `fn main() {}`, LLVM
917 // will optimize out calls to `__morestack` entirely because the function
918 // doesn't need any stack at all!
920 // To get around this snag, we specially tell the linker to always include
921 // all contents of this library. This way we're guaranteed that the linker
922 // will include the __morestack symbol 100% of the time, always resolving
923 // references to it even if the object above didn't use it.
924 if t
.options
.morestack
{
925 cmd
.link_whole_staticlib("morestack", &[lib_path
]);
928 // When linking a dynamic library, we put the metadata into a section of the
929 // executable. This metadata is in a separate object file from the main
930 // object file, so we link that in here.
932 cmd
.add_object(&outputs
.with_extension("metadata.o"));
935 // Try to strip as much out of the generated object by removing unused
936 // sections if possible. See more comments in linker.rs
937 cmd
.gc_sections(dylib
);
939 let used_link_args
= sess
.cstore
.get_used_link_args().borrow();
941 if !dylib
&& t
.options
.position_independent_executables
{
942 let empty_vec
= Vec
::new();
943 let empty_str
= String
::new();
944 let args
= sess
.opts
.cg
.link_args
.as_ref().unwrap_or(&empty_vec
);
945 let mut args
= args
.iter().chain(used_link_args
.iter());
946 let relocation_model
= sess
.opts
.cg
.relocation_model
.as_ref()
947 .unwrap_or(&empty_str
);
948 if (t
.options
.relocation_model
== "pic" || *relocation_model
== "pic")
949 && !args
.any(|x
| *x
== "-static") {
950 cmd
.position_independent_executable();
954 // Pass optimization flags down to the linker.
957 // Pass debuginfo flags down to the linker.
960 // We want to prevent the compiler from accidentally leaking in any system
961 // libraries, so we explicitly ask gcc to not link to any libraries by
962 // default. Note that this does not happen for windows because windows pulls
963 // in some large number of libraries and I couldn't quite figure out which
965 cmd
.no_default_libraries();
967 // Take careful note of the ordering of the arguments we pass to the linker
968 // here. Linkers will assume that things on the left depend on things to the
969 // right. Things on the right cannot depend on things on the left. This is
970 // all formally implemented in terms of resolving symbols (libs on the right
971 // resolve unknown symbols of libs on the left, but not vice versa).
973 // For this reason, we have organized the arguments we pass to the linker as
976 // 1. The local object that LLVM just generated
977 // 2. Upstream rust libraries
978 // 3. Local native libraries
979 // 4. Upstream native libraries
981 // This is generally fairly natural, but some may expect 2 and 3 to be
982 // swapped. The reason that all native libraries are put last is that it's
983 // not recommended for a native library to depend on a symbol from a rust
984 // crate. If this is the case then a staticlib crate is recommended, solving
987 // Additionally, it is occasionally the case that upstream rust libraries
988 // depend on a local native library. In the case of libraries such as
989 // lua/glfw/etc the name of the library isn't the same across all platforms,
990 // so only the consumer crate of a library knows the actual name. This means
991 // that downstream crates will provide the #[link] attribute which upstream
992 // crates will depend on. Hence local native libraries are after out
993 // upstream rust crates.
995 // In theory this means that a symbol in an upstream native library will be
996 // shadowed by a local native library when it wouldn't have been before, but
997 // this kind of behavior is pretty platform specific and generally not
998 // recommended anyway, so I don't think we're shooting ourself in the foot
1000 add_upstream_rust_crates(cmd
, sess
, dylib
, tmpdir
, trans
);
1001 add_local_native_libraries(cmd
, sess
);
1002 add_upstream_native_libraries(cmd
, sess
);
1004 // # Telling the linker what we're doing
1007 cmd
.build_dylib(out_filename
);
1010 // FIXME (#2397): At some point we want to rpath our guesses as to
1011 // where extern libraries might live, based on the
1012 // addl_lib_search_paths
1013 if sess
.opts
.cg
.rpath
{
1014 let sysroot
= sess
.sysroot();
1015 let target_triple
= &sess
.opts
.target_triple
;
1016 let mut get_install_prefix_lib_path
= || {
1017 let install_prefix
= option_env
!("CFG_PREFIX").expect("CFG_PREFIX");
1018 let tlib
= filesearch
::relative_target_lib_path(sysroot
, target_triple
);
1019 let mut path
= PathBuf
::from(install_prefix
);
1024 let mut rpath_config
= RPathConfig
{
1025 used_crates
: sess
.cstore
.get_used_crates(cstore
::RequireDynamic
),
1026 out_filename
: out_filename
.to_path_buf(),
1027 has_rpath
: sess
.target
.target
.options
.has_rpath
,
1028 is_like_osx
: sess
.target
.target
.options
.is_like_osx
,
1029 get_install_prefix_lib_path
: &mut get_install_prefix_lib_path
,
1031 cmd
.args(&rpath
::get_rpath_flags(&mut rpath_config
));
1034 // Finally add all the linker arguments provided on the command line along
1035 // with any #[link_args] attributes found inside the crate
1036 if let Some(ref args
) = sess
.opts
.cg
.link_args
{
1039 cmd
.args(&used_link_args
);
1042 // # Native library linking
1044 // User-supplied library search paths (-L on the command line). These are
1045 // the same paths used to find Rust crates, so some of them may have been
1046 // added already by the previous crate linking code. This only allows them
1047 // to be found at compile time so it is still entirely up to outside
1048 // forces to make sure that library can be found at runtime.
1050 // Also note that the native libraries linked here are only the ones located
1051 // in the current crate. Upstream crates with native library dependencies
1052 // may have their native library pulled in above.
1053 fn add_local_native_libraries(cmd
: &mut Linker
, sess
: &Session
) {
1054 sess
.target_filesearch(PathKind
::All
).for_each_lib_search_path(|path
, k
| {
1056 PathKind
::Framework
=> { cmd.framework_path(path); }
1057 _
=> { cmd.include_path(&fix_windows_verbatim_for_gcc(path)); }
1062 let libs
= sess
.cstore
.get_used_libraries();
1063 let libs
= libs
.borrow();
1065 let staticlibs
= libs
.iter().filter_map(|&(ref l
, kind
)| {
1066 if kind
== cstore
::NativeStatic {Some(l)}
else {None}
1068 let others
= libs
.iter().filter(|&&(_
, kind
)| {
1069 kind
!= cstore
::NativeStatic
1072 // Some platforms take hints about whether a library is static or dynamic.
1073 // For those that support this, we ensure we pass the option if the library
1074 // was flagged "static" (most defaults are dynamic) to ensure that if
1075 // libfoo.a and libfoo.so both exist that the right one is chosen.
1078 let search_path
= archive_search_paths(sess
);
1079 for l
in staticlibs
{
1080 // Here we explicitly ask that the entire archive is included into the
1081 // result artifact. For more details see #15460, but the gist is that
1082 // the linker will strip away any unused objects in the archive if we
1083 // don't otherwise explicitly reference them. This can occur for
1084 // libraries which are just providing bindings, libraries with generic
1086 cmd
.link_whole_staticlib(l
, &search_path
);
1091 for &(ref l
, kind
) in others
{
1093 cstore
::NativeUnknown
=> cmd
.link_dylib(l
),
1094 cstore
::NativeFramework
=> cmd
.link_framework(l
),
1095 cstore
::NativeStatic
=> unreachable
!(),
1100 // # Rust Crate linking
1102 // Rust crates are not considered at all when creating an rlib output. All
1103 // dependencies will be linked when producing the final output (instead of
1104 // the intermediate rlib version)
1105 fn add_upstream_rust_crates(cmd
: &mut Linker
, sess
: &Session
,
1106 dylib
: bool
, tmpdir
: &Path
,
1107 trans
: &CrateTranslation
) {
1108 // All of the heavy lifting has previously been accomplished by the
1109 // dependency_format module of the compiler. This is just crawling the
1110 // output of that module, adding crates as necessary.
1112 // Linking to a rlib involves just passing it to the linker (the linker
1113 // will slurp up the object files inside), and linking to a dynamic library
1114 // involves just passing the right -l flag.
1116 let data
= if dylib
{
1117 trans
.crate_formats
.get(&config
::CrateTypeDylib
).unwrap()
1119 trans
.crate_formats
.get(&config
::CrateTypeExecutable
).unwrap()
1122 // Invoke get_used_crates to ensure that we get a topological sorting of
1124 let deps
= sess
.cstore
.get_used_crates(cstore
::RequireDynamic
);
1126 for &(cnum
, _
) in &deps
{
1127 // We may not pass all crates through to the linker. Some crates may
1128 // appear statically in an existing dylib, meaning we'll pick up all the
1129 // symbols from the dylib.
1130 let kind
= match data
[cnum
as usize - 1] {
1134 let src
= sess
.cstore
.get_used_crate_source(cnum
).unwrap();
1136 cstore
::RequireDynamic
=> {
1137 add_dynamic_crate(cmd
, sess
, &src
.dylib
.unwrap().0)
1139 cstore
::RequireStatic
=> {
1140 add_static_crate(cmd
, sess
, tmpdir
, dylib
, &src
.rlib
.unwrap().0)
1146 // Converts a library file-stem into a cc -l argument
1147 fn unlib
<'a
>(config
: &config
::Config
, stem
: &'a
str) -> &'a
str {
1148 if stem
.starts_with("lib") && !config
.target
.options
.is_like_windows
{
1155 // Adds the static "rlib" versions of all crates to the command line.
1156 // There's a bit of magic which happens here specifically related to LTO and
1157 // dynamic libraries. Specifically:
1159 // * For LTO, we remove upstream object files.
1160 // * For dylibs we remove metadata and bytecode from upstream rlibs
1162 // When performing LTO, all of the bytecode from the upstream libraries has
1163 // already been included in our object file output. As a result we need to
1164 // remove the object files in the upstream libraries so the linker doesn't
1165 // try to include them twice (or whine about duplicate symbols). We must
1166 // continue to include the rest of the rlib, however, as it may contain
1167 // static native libraries which must be linked in.
1169 // When making a dynamic library, linkers by default don't include any
1170 // object files in an archive if they're not necessary to resolve the link.
1171 // We basically want to convert the archive (rlib) to a dylib, though, so we
1172 // *do* want everything included in the output, regardless of whether the
1173 // linker thinks it's needed or not. As a result we must use the
1174 // --whole-archive option (or the platform equivalent). When using this
1175 // option the linker will fail if there are non-objects in the archive (such
1176 // as our own metadata and/or bytecode). All in all, for rlibs to be
1177 // entirely included in dylibs, we need to remove all non-object files.
1179 // Note, however, that if we're not doing LTO or we're not producing a dylib
1180 // (aka we're making an executable), we can just pass the rlib blindly to
1181 // the linker (fast) because it's fine if it's not actually included as
1182 // we're at the end of the dependency chain.
1183 fn add_static_crate(cmd
: &mut Linker
, sess
: &Session
, tmpdir
: &Path
,
1184 dylib
: bool
, cratepath
: &Path
) {
1185 if !sess
.lto() && !dylib
{
1186 cmd
.link_rlib(&fix_windows_verbatim_for_gcc(cratepath
));
1190 let dst
= tmpdir
.join(cratepath
.file_name().unwrap());
1191 let name
= cratepath
.file_name().unwrap().to_str().unwrap();
1192 let name
= &name
[3..name
.len() - 5]; // chop off lib/.rlib
1194 time(sess
.time_passes(), &format
!("altering {}.rlib", name
), (), |()| {
1195 let cfg
= archive_config(sess
, &dst
, Some(cratepath
));
1196 let mut archive
= ArchiveBuilder
::new(cfg
);
1197 archive
.remove_file(METADATA_FILENAME
);
1198 archive
.update_symbols();
1200 let mut any_objects
= false;
1201 for f
in archive
.src_files() {
1202 if f
.ends_with("bytecode.deflate") {
1203 archive
.remove_file(&f
);
1206 let canonical
= f
.replace("-", "_");
1207 let canonical_name
= name
.replace("-", "_");
1208 if sess
.lto() && canonical
.starts_with(&canonical_name
) &&
1209 canonical
.ends_with(".o") {
1210 let num
= &f
[name
.len()..f
.len() - 2];
1211 if num
.len() > 0 && num
[1..].parse
::<u32>().is_ok() {
1212 archive
.remove_file(&f
);
1221 cmd
.link_whole_rlib(&fix_windows_verbatim_for_gcc(&dst
));
1226 // Same thing as above, but for dynamic crates instead of static crates.
1227 fn add_dynamic_crate(cmd
: &mut Linker
, sess
: &Session
, cratepath
: &Path
) {
1228 // If we're performing LTO, then it should have been previously required
1229 // that all upstream rust dependencies were available in an rlib format.
1230 assert
!(!sess
.lto());
1232 // Just need to tell the linker about where the library lives and
1234 let parent
= cratepath
.parent();
1235 if let Some(dir
) = parent
{
1236 cmd
.include_path(&fix_windows_verbatim_for_gcc(dir
));
1238 let filestem
= cratepath
.file_stem().unwrap().to_str().unwrap();
1239 cmd
.link_rust_dylib(&unlib(&sess
.target
, filestem
),
1240 parent
.unwrap_or(Path
::new("")));
1244 // Link in all of our upstream crates' native dependencies. Remember that
1245 // all of these upstream native dependencies are all non-static
1246 // dependencies. We've got two cases then:
1248 // 1. The upstream crate is an rlib. In this case we *must* link in the
1249 // native dependency because the rlib is just an archive.
1251 // 2. The upstream crate is a dylib. In order to use the dylib, we have to
1252 // have the dependency present on the system somewhere. Thus, we don't
1253 // gain a whole lot from not linking in the dynamic dependency to this
1256 // The use case for this is a little subtle. In theory the native
1257 // dependencies of a crate are purely an implementation detail of the crate
1258 // itself, but the problem arises with generic and inlined functions. If a
1259 // generic function calls a native function, then the generic function must
1260 // be instantiated in the target crate, meaning that the native symbol must
1261 // also be resolved in the target crate.
1262 fn add_upstream_native_libraries(cmd
: &mut Linker
, sess
: &Session
) {
1263 // Be sure to use a topological sorting of crates because there may be
1264 // interdependencies between native libraries. When passing -nodefaultlibs,
1265 // for example, almost all native libraries depend on libc, so we have to
1266 // make sure that's all the way at the right (liblibc is near the base of
1267 // the dependency chain).
1269 // This passes RequireStatic, but the actual requirement doesn't matter,
1270 // we're just getting an ordering of crate numbers, we're not worried about
1272 let crates
= sess
.cstore
.get_used_crates(cstore
::RequireStatic
);
1273 for (cnum
, _
) in crates
{
1274 let libs
= csearch
::get_native_libraries(&sess
.cstore
, cnum
);
1275 for &(kind
, ref lib
) in &libs
{
1277 cstore
::NativeUnknown
=> cmd
.link_dylib(lib
),
1278 cstore
::NativeFramework
=> cmd
.link_framework(lib
),
1279 cstore
::NativeStatic
=> {
1280 sess
.bug("statics shouldn't be propagated");