Commit Graph

487 Commits

Author SHA1 Message Date
Rui Ueyama f43fba739c Revert r336609: Fix direct calls to __wrap_sym when it is relocated.
This reverts commit r336609 as it doesn't seem to work with AArch64
thunk creation when used with ASan.

llvm-svn: 337413
2018-07-18 18:24:46 +00:00
George Rimar fd6af6dc98 [ELF] - Report proper error message about mixing bitcode files.
If we have 2 bitcode inputs for different targets, LLD would
print "<internal>" instead of the name of one of the files.

The patch adds a test and fixes this issue.

llvm-svn: 336794
2018-07-11 12:32:00 +00:00
Rui Ueyama 3e730b8ae6 Fix direct calls to __wrap_sym when it is relocated.
Patch by Matthew Koontz!

Before, direct calls to __wrap_sym would not map to valid PLT entries,
so they would crash at runtime. This change maps such calls to the same
PLT entry as calls to sym that are then wrapped.

Differential Revision: https://reviews.llvm.org/D48502

llvm-svn: 336609
2018-07-09 22:03:05 +00:00
George Rimar 2051bd02a7 [ELF] - Replace llvm::find_if with the loop. NFC.
Requested during post commit review.

llvm-svn: 335447
2018-06-25 09:30:39 +00:00
George Rimar c9c0ccc8a9 [ELF] - Change how we handle suplicate -wrap. [NFC]
This avoids doing llvm::sort and std::unique for -wrap options.
I think it is more clean way.

llvm-svn: 335337
2018-06-22 11:18:11 +00:00
Rui Ueyama 9867c9e2bf Fix typo.
llvm-svn: 332859
2018-05-21 18:12:46 +00:00
Benjamin Kramer 5455038d98 [lld] Make helpers static. NFC.
llvm-svn: 332408
2018-05-15 22:01:54 +00:00
Fangrui Song c638db5913 [ELF] --warn-backref: don't report backref to weak symbols.
Summary:
Suppose we visit symbols in this order:

1. weak definition of foo in a lazy object
2. reference of foo
3 (optional). definition of foo

bfd/gold allows 123 but not 12.

Current --warn-backrefs implementation will report both cases as a backward reference. With this change, both 123 (intended) and 12 (unintended) are allowed. The usage of weak definitions usually imply there are also global definitions, so the trade-off is justified.

Reviewers: ruiu, espindola

Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D46624

llvm-svn: 332061
2018-05-10 23:53:05 +00:00
Rumeet Dhindsa d366e36bbf Added support for ThinLTO plugin options : thinlto-index-only and thinlto-prefix-replace
Differential Revision: https://reviews.llvm.org/D46034

llvm-svn: 331405
2018-05-02 21:40:07 +00:00
George Rimar 19f9b814dd [ELF] - Refactor lazy symbol duplicated code.
Our code for LazyObject and LazyArchive duplicates.

This patch extracts the common part to remove
the duplication.

Differential revision: https://reviews.llvm.org/D45516

llvm-svn: 330701
2018-04-24 09:41:56 +00:00
Fangrui Song c8ac0a6f97 [ELF] Swap argument names: use Old to refer to original symbol and New for incoming one
Reviewers: ruiu, espindola

Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D45905

llvm-svn: 330491
2018-04-20 22:50:15 +00:00
Rui Ueyama 1d92aa7380 Add --warn-backrefs to maintain compatibility with other linkers
I'm proposing a new command line flag, --warn-backrefs in this patch.
The flag and the feature proposed below don't exist in GNU linkers
nor the current lld.

--warn-backrefs is an option to detect reverse or cyclic dependencies
between static archives, and it can be used to keep your program
compatible with GNU linkers after you switch to lld. I'll explain the
feature and why you may find it useful below.

lld's symbol resolution semantics is more relaxed than traditional
Unix linkers. Therefore,

  ld.lld foo.a bar.o

succeeds even if bar.o contains an undefined symbol that have to be
resolved by some object file in foo.a. Traditional Unix linkers
don't allow this kind of backward reference, as they visit each
file only once from left to right in the command line while
resolving all undefined symbol at the moment of visiting.

In the above case, since there's no undefined symbol when a linker
visits foo.a, no files are pulled out from foo.a, and because the
linker forgets about foo.a after visiting, it can't resolve
undefined symbols that could have been resolved otherwise.

That lld accepts more relaxed form means (besides it makes more
sense) that you can accidentally write a command line or a build
file that works only with lld, even if you have a plan to
distribute it to wider users who may be using GNU linkers.  With
--check-library-dependency, you can detect a library order that
doesn't work with other Unix linkers.

The option is also useful to detect cyclic dependencies between
static archives. Again, lld accepts

  ld.lld foo.a bar.a

even if foo.a and bar.a depend on each other. With --warn-backrefs
it is handled as an error.

Here is how the option works. We assign a group ID to each file. A
file with a smaller group ID can pull out object files from an
archive file with an equal or greater group ID. Otherwise, it is a
reverse dependency and an error.

A file outside --{start,end}-group gets a fresh ID when
instantiated. All files within the same --{start,end}-group get the
same group ID. E.g.

  ld.lld A B --start-group C D --end-group E

A and B form group 0, C, D and their member object files form group
1, and E forms group 2. I think that you can see how this group
assignment rule simulates the traditional linker's semantics.

Differential Revision: https://reviews.llvm.org/D45195

llvm-svn: 329636
2018-04-09 23:05:48 +00:00
Rui Ueyama 90f13ed0e4 Return early. NFC.
llvm-svn: 329126
2018-04-03 22:39:12 +00:00
Rui Ueyama d35b839c3f Merge two `if`s and add a few blank lines. NFC.
llvm-svn: 329125
2018-04-03 22:39:04 +00:00
Rui Ueyama 61b67abe89 Fix buildbots.
r329092 broke buildbots.

llvm-svn: 329103
2018-04-03 18:59:31 +00:00
Rui Ueyama cc013f62c1 Make fetchIfLazy only fetch an object file. NFC.
Previously, fetchIfLazy did more than the name says. Now, setting
to UsedInRegularObj is moved to another function.

llvm-svn: 329092
2018-04-03 18:01:18 +00:00
George Rimar 1ef746ba21 [ELF] - Eliminate Lazy class.
Patch removes Lazy class which
is just an excessive layer.

Differential revision: https://reviews.llvm.org/D45083

llvm-svn: 329086
2018-04-03 17:16:52 +00:00
Rui Ueyama 24a47201fd Merge LazyArchive::fetch() and ArchiveFile::getMember(). NFC.
They are to pull out an object file for a symbol, but for a historical
reason the code is written in two separate functions. This patch
merges them.

llvm-svn: 329039
2018-04-03 02:06:57 +00:00
Rafael Espindola c8f774b393 Strip @VER suffices from the LTO output.
This fixes pr36623.

The problem is that we have to parse versions out of names before LTO
so that LTO can use that information.

When we get the LTO produced .o files, we replace the previous symbols
with the LTO produced ones, but they still have @ in their names.

We could just trim the name directly, but calling parseSymbolVersion
to do it is simpler.

llvm-svn: 328738
2018-03-28 22:45:39 +00:00
Rui Ueyama 048a669b92 allow-multiple-definitions should completely suppress errors instead of making them warnings.
We found that when you pass --allow-multiple-definitions or `-z muldefs`
to GNU linkers, they don't complain about duplicate symbols at all. They
don't even print out warnings on it. We emit warnings in that case.
If you pass --fatal-warnings, that difference results in a link failure.

Differential Revision: https://reviews.llvm.org/D44549

llvm-svn: 327920
2018-03-19 23:04:04 +00:00
Rafael Espindola ddb33c0961 Improve duplicated version handling.
It looks like the problem that caused us to originally warn instead of
error was that of a symbol being assigned to the same version twice.

Now we don't warn if a symbol is assigned to the same version twice,
but error if it is assigned to multiple.

This fixes pr28342.

llvm-svn: 326813
2018-03-06 17:05:12 +00:00
Rafael Espindola e3a6062844 Simplify. NFC.
Since r321982 we don't set VersionId in scanShlibUndefined, which
makes InVersionScript redundant.

llvm-svn: 326641
2018-03-03 02:13:50 +00:00
Rafael Espindola 3f4c673d38 Put undefined symbols from shared libraries in the symbol table.
With the recent fixes these symbols have more in common than not with
regular undefined symbols.

llvm-svn: 326242
2018-02-27 20:31:22 +00:00
Igor Kudrin 3345c9ac18 [ELF] Create and export symbols provided by a linker script if they referenced by DSOs.
It should be possible to resolve undefined symbols in dynamic libraries
using symbols defined in a linker script.

Differential Revision: https://reviews.llvm.org/D43011

llvm-svn: 326176
2018-02-27 07:18:07 +00:00
Rui Ueyama c30927411c Make undefined symbol in DSO to pull out object files from archive files.
We have an internal program that does't link without this patch. I don't
know of any open-source program that needs this, but there might be.
Since this patch improves compatibility with GNU linkers with a few lines
of code, I think it's worth to be committed.

The problem is about undefined symbols in DSOs. Some programs depend on
the GNU linkers' behavior that they pull out object files from archive
files to resolve undefined symbols in DSOs. We already allow that kind of
"reverse" dependency (from DSOs to the main executable) for regular
symbols, in particular, for "__progname" symbol (which is usually in
crt0.o), but that doesn't work if the symbol is in an archive file.
This patch is to make it work.

Differential Revision: https://reviews.llvm.org/D43658

llvm-svn: 325849
2018-02-23 01:16:57 +00:00
Peter Collingbourne 09e04af42f ELF: Stop collecting a list of symbols in ArchiveFile.
There seems to be no reason to collect this list of symbols.

Also fix a bug where --exclude-libs would apply to all symbols that
appear in an archive's symbol table, even if the relevant archive
member was not added to the link.

Differential Revision: https://reviews.llvm.org/D43369

llvm-svn: 325380
2018-02-16 20:23:54 +00:00
Rui Ueyama 6de1e858a1 Fix an issue that weak bit is dropped when there's a lazy object symbol.
Previously, we accidentally dropped STB_WEAK bit from an undefined symbol
if there is a lazy object symbol with the same name. That caused a
compatibility issue with GNU gold.

llvm-svn: 325316
2018-02-16 04:27:46 +00:00
Rui Ueyama af7242a385 Use reinterpret_cast<> instead of C-style cast. NFC.
It is currently interpreted as reinterpret_cast<>. Make it explicit.

Differential Revision: https://reviews.llvm.org/D43247

llvm-svn: 325033
2018-02-13 18:11:42 +00:00
Rui Ueyama aad2e328b9 Add --no-gnu-unique and --no-undefined-version for completeness.
Differential Revision: https://reviews.llvm.org/D42865

llvm-svn: 324145
2018-02-02 21:44:06 +00:00
George Rimar fd5a33d623 [ELF] - Do not forget file name when reporting duplicate symbol error for absolute symbols.
When there is a duplicate absolute symbol, LLD reports <internal>
instead of known object file name currently.
Patch fixes the issue.

Differential revision: https://reviews.llvm.org/D42636

llvm-svn: 323849
2018-01-31 08:32:35 +00:00
Rafael Espindola 8e2fc4f3f8 Don't mark a shared library as needed because of a lazy symbol.
Fixes PR36029.

llvm-svn: 323221
2018-01-23 16:59:20 +00:00
Rafael Espindola 7e6aeb614c Fix another case we used the wrong visibility.
In here too we want the computed output visibility.

llvm-svn: 322586
2018-01-16 19:02:46 +00:00
Easwaran Raman bfa48a14ab [ELF] Explicit template instantiations for addFile
Summary:
All other templated methods have explicit instantiations but this one is
missing. Discovered while building with a clang with inliner
modifications.

Reviewers: espindola

Subscribers: emaste, llvm-commits, davidxl

Differential Revision: https://reviews.llvm.org/D41847

llvm-svn: 322057
2018-01-09 05:35:29 +00:00
Shoaib Meenai c1ca8065b5 [ELF] Small grammar fix. NFC
The whole consists of the parts, not the other way around.

llvm-svn: 322042
2018-01-08 23:18:16 +00:00
Shoaib Meenai 3a15fb591e [ELF] Drop unnecessary VersionId setting in scanShlibUndefined
LLD previously used to handle dynamic lists and version scripts in the
exact same way, even though they have very different semantics for
shared libraries and subtly different semantics for executables. r315114
untangled their semantics for executables (building on previous work to
correct their semantics for shared libraries). With that change, dynamic
lists won't set the default version to VER_NDX_LOCAL, and so resetting
the version to VER_NDX_GLOBAL in scanShlibUndefined is unnecessary.

This was causing an issue because version scripts containing `local: *`
work by setting the default version to VER_NDX_LOCAL, but scanShlibUndefined
would override this default, and therefore symbols which should have
been local would end up in the dynamic symbol table, which differs from
both bfd and gold's behavior. gold silently keeps the symbol hidden in
such a scenario, whereas bfd issues an error. I prefer bfd's behavior
and plan to implement that in LLD in a follow-up (and the test case
added here will be updated accordingly).

Differential Revision: https://reviews.llvm.org/D41639

llvm-svn: 321982
2018-01-08 05:53:11 +00:00
Rafael Espindola 9a84f6b954 Detemplate reportDuplicate.
We normally avoid "switch (Config->EKind)", but in this case I think
it is worth it.

It is only executed when there is an error and it allows detemplating
a lot of code.

llvm-svn: 321404
2017-12-23 17:21:39 +00:00
Rafael Espindola 9f37543cf8 Detemplate isCompatible(). NFC.
llvm-svn: 321393
2017-12-23 00:04:34 +00:00
Rafael Espindola 8276f1bda6 Use a reference to a file in the LazyArchive symbol.
It is never null.

llvm-svn: 321198
2017-12-20 17:59:43 +00:00
Rafael Espindola 2e5c71eadc LazyObject's file is never null, use a reference.
llvm-svn: 321196
2017-12-20 17:52:36 +00:00
Rafael Espindola 8cd6674f5b Use a reference in addLazyArchive. NFC.
llvm-svn: 321194
2017-12-20 17:48:28 +00:00
Rafael Espindola a32ddc4639 Use a reference for the shared symbol file.
Every shared symbol has a file, so we can use a reference.

llvm-svn: 321187
2017-12-20 16:28:19 +00:00
Rafael Espindola 7b5cc6c5dc Use a reference for a value that is never null. NFC.
llvm-svn: 321186
2017-12-20 16:19:48 +00:00
Rafael Espindola f1687125ba Use a reference for a value that is never null. NFC.
llvm-svn: 321185
2017-12-20 16:16:40 +00:00
Rafael Espindola 092ba58bee Replace a dyn_cast_or_null with dyn_cast.
The variable being casted was accessed in the previous line.

llvm-svn: 321140
2017-12-20 01:57:19 +00:00
Rui Ueyama fbe68a3584 Use warn() instead of error() to report a bad symbol in a DSO.
Specifically, libwidevinecdm.so in Chrome has such bad symbol.
It seems the BFD linker handles them as local symbols, so instead
of inserting them to the symbol table, we should skip them too.

Differential Revision: https://reviews.llvm.org/D41257

llvm-svn: 320770
2017-12-15 00:01:33 +00:00
Rafael Espindola b308cace84 Fix crash on invalid.
We would fail an assert if a shared library had a local symbol after
sh_info.

llvm-svn: 320667
2017-12-14 05:01:49 +00:00
Rafael Espindola 8f619ab826 Compact symbols from 96 to 88 bytes.
By using an index instead of a pointer for verdef we can put the index
next to the alignment field. This uses the otherwise wasted area and
reduces the shared symbol size.

By itself the performance change of this is in the noise, but I have a
followup patch to remove another 8 bytes that improves performance
when combined with this.

llvm-svn: 320449
2017-12-12 01:45:49 +00:00
Evgeniy Stepanov 9ac3154d10 [lld] Fix handling of wildcards in dynamic lists.
Reviewers: pcc, ruiu

Subscribers: llvm-commits, emaste

Differential Revision: https://reviews.llvm.org/D40868

llvm-svn: 319860
2017-12-06 00:14:04 +00:00
Rafael Espindola b2ee25ac8a Simplify. NFC.
This particular reportDuplicate is only used with Defined.

llvm-svn: 319451
2017-11-30 18:02:04 +00:00
Rafael Espindola dfebd3601d Use Symbol::File directly.
We are already paying the cost of storing a InputFile in every
Symbol, so use it uniformly.

llvm-svn: 319378
2017-11-29 22:47:35 +00:00