Commit Graph

55 Commits

Author SHA1 Message Date
Amy Huang 7b1d793713 Reland "Change the X86 datalayout to add three address spaces
for 32 bit signed, 32 bit unsigned, and 64 bit pointers."
This reverts 57076d3199.

Original review at https://reviews.llvm.org/D64931.
Review for added fix at https://reviews.llvm.org/D66843.

llvm-svn: 371568
2019-09-10 23:15:38 +00:00
Fangrui Song 688183ec54 [ELF] Set `referenced` bit of Undefined created by BitcodeFile
D64136 and D65584, while fixing STB_WEAK issues and improving our
compatibility with ld.bfd, can cause another STB_WEAK problem related to
LTO:

If %tundef.o has an undefined reference on f,
and %tweakundef.o has a weak undefined reference on f,
%tdef.o has a definition of f

```
ld.lld %tundef.o %tweakundef.o --start-lib %tdef.o --end-lib
```

1) `%tundef.o` doesn't set the `referenced` bit.
2) `%weakundef.o` changes the binding from STB_GLOBAL to STB_WEAK
3) `%tdef.o` is not fetched because the binding is weak.

Step (1) is incorrect. This patch sets the `referenced` bit of Undefined
created by bitcode files.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D66992

llvm-svn: 370437
2019-08-30 07:10:30 +00:00
Vlad Tsyrklevich 57076d3199 Revert "Change the X86 datalayout to add three address spaces for 32 bit signed,"
This reverts commit r370083 because it caused check-lld failures on
sanitizer-x86_64-linux-fast.

llvm-svn: 370142
2019-08-28 01:08:54 +00:00
Amy Huang 1299945b81 Change the X86 datalayout to add three address spaces for 32 bit signed,
32 bit unsigned, and 64 bit pointers.

llvm-svn: 370083
2019-08-27 17:46:53 +00:00
Igor Kudrin 4669cf2750 [LTO] Improve readability of module IDs
Module IDs can appear in diagnostic messages.
This patch adds some auxiliary symbols to improve their readability.

Differential Revision: https://reviews.llvm.org/D61857

llvm-svn: 360858
2019-05-16 05:23:25 +00:00
Bill Wendling 01706bda5b Output ELF files after ThinLTO is run.
Summary:
The gold linker allowed you to output the ELF files after LTO was run. It did
it by using the 'obj-path' option. This replicates that behavior.

Reviewers: espindola, ruiu, MaskRay, pcc

Reviewed By: MaskRay, pcc

Subscribers: grimar, emaste, inglorion, arichardson, steven_wu, dexonsmith, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D56046

llvm-svn: 354917
2019-02-26 19:29:14 +00:00
Peter Collingbourne 98930115ea ELF: Only add libcall symbols to the link if defined in bitcode.
Adding all libcall symbols to the link can have undesired consequences.
For example, the libgcc implementation of __sync_val_compare_and_swap_8
on 32-bit ARM pulls in an .init_array entry that aborts the program if
the Linux kernel does not support 64-bit atomics, which would prevent
the program from running even if it does not use 64-bit atomics.

This change makes it so that we only add libcall symbols to the
link before LTO if we have to, i.e. if the symbol's definition is in
bitcode. Any other required libcall symbols will be added to the link
after LTO when we add the LTO object file to the link.

Differential Revision: https://reviews.llvm.org/D50475

llvm-svn: 339301
2018-08-08 23:48:12 +00:00
Peter Collingbourne 2da4e52182 ELF: Add libcall symbols to the link when LTO is being used.
If any of our inputs are bitcode files, the LTO code generator may create
references to certain library functions that might not be explicit in the
bitcode file's symbol table. If any of those library functions are defined
in a bitcode file in an archive member, we need to arrange to use LTO to
compile those archive members by adding them to the link beforehand.

Differential Revision: https://reviews.llvm.org/D50017

llvm-svn: 338434
2018-07-31 20:36:17 +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
Sam Clegg b2144058a6 [LTO] Errors in LLVM backend should manifest as lld errors
Differential Revision: https://reviews.llvm.org/D48812

llvm-svn: 336143
2018-07-02 21:01:43 +00:00
Sam Clegg 3d63a409a0 [ELF] Remove -m argument to lld in test files. NFC.
This should be correctly implied by the linker.

This also makes the tests slightly easier to maintain and compare
with the equivalent tests under for other platforms.

Differential Revision: https://reviews.llvm.org/D47513

llvm-svn: 333567
2018-05-30 17:57:08 +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
Rafael Espindola 03d7a1bc46 Add a test for an issue fixed in r329092.
We were setting IsUsedInRegularObj in lazy symbols only used from IR.

llvm-svn: 329101
2018-04-03 18:35:46 +00:00
George Rimar 1fdb280bec [ELF] - Added testcase for testing visibility of weak_odr symbols.
This is relative to "Bug 36166 - tools/gold/X86/comdat.ll is failing only on Debian Unstable" (PR36166).
Something changed in newer versions of gold and now together with gold-plugin
there is an issue shown in PR, symbol may get wrong visibility.

LLD works fine, but we have no testcase for the same use case, patch adds it.

Differential revision: https://reviews.llvm.org/D43193

llvm-svn: 325874
2018-02-23 10:08:15 +00:00
Dmitry Mikulin c84e0ee0e2 Don't set dso_local flag in LTO resolutions for absolute symbols defined in ELF
objects, it confuses codegen into generating pc-rel relocations for those
symbols, which leads to linker errors.

Differential Revision: https://reviews.llvm.org/D42977

llvm-svn: 324435
2018-02-07 00:49:51 +00:00
George Rimar 37304c475a [ELF] - Extend lto/asmundef.ll testcase.
Patch adds one more module with non-prevailing
version of asm symbol, defined in main module

This is for D42107, which is under review. 
Extended version of testcase would fail with the
diff 9 version of patch posted.

llvm-svn: 323584
2018-01-27 09:04:47 +00:00
George Rimar d28c26bbdd [ELF] - LTO: do not optimize away symbols accessed from linkerscript.
Previously when BC file had global variable that was accessed from script,
it was optimized away or inlined by IPO. 
In this patch I add symbols at left side of assignment expression as LinkerRedefined,
what prevents optimization for them.

Differential revision: https://reviews.llvm.org/D37059

llvm-svn: 314097
2017-09-25 09:31:43 +00:00
Davide Italiano 957f1206e9 [LTO] Make sure symbol ordering is honoured also for data.
Follow-up to r308915 suggested by Rafael and Peter.

llvm-svn: 308920
2017-07-24 20:15:07 +00:00
Davide Italiano 1f4e29c71d [LTO] Make sure symbol ordering is honoured.
We do this emitting a section for every function when LTO is used.
Fixes PR33888.

Differential Revision:  https://reviews.llvm.org/D35809

llvm-svn: 308915
2017-07-24 19:38:13 +00:00
Dmitry Mikulin db3b87b2c0 Symbols re-defined with -wrap and -defsym need to be excluded from inter-
procedural optimizations to prevent dropping symbols and allow the linker
to process re-directs.

PR33145: --wrap doesn't work with lto.
Differential Revision: https://reviews.llvm.org/D33621

llvm-svn: 304719
2017-06-05 16:24:25 +00:00
Evgeniy Stepanov f12ac5b776 [lld] Infer relocation model from module flags in relocatable LTO link.
Fix for PR33096.

llvm-svn: 303579
2017-05-22 21:11:44 +00:00
Rafael Espindola 80ae8ae186 Remember archive name when creating LazyObjectFile.
It is needed for creating an unique identifier for ThinLTO.

This fixes pr32931.

llvm-svn: 302235
2017-05-05 13:55:51 +00:00
Peter Collingbourne 1fd02112df Address a few nits pointed out by Sean.
llvm-svn: 296728
2017-03-02 02:24:31 +00:00
Peter Collingbourne e02775f068 ELF: Add ThinLTO caching support.
This patch adds an option named --thinlto-cache-dir, which specifies the
path to a directory in which to cache native object files for ThinLTO
incremental builds.

Differential Revision: https://reviews.llvm.org/D30509

llvm-svn: 296702
2017-03-01 23:00:10 +00:00
Davide Italiano bcdd6c60a0 [ThinLTO] Avoid archive member collisions.
This fixes PR30665.

Differential Revision:  https://reviews.llvm.org/D25495

llvm-svn: 284034
2016-10-12 19:35:54 +00:00
Davide Italiano 7a7b35ae3b [LTO/Thin] Make the number of threads to run in the BE configurable.
Before the default was whatever number hardware_concurrency() returned.
Users can specify the number of threads via --lto-jobs=X option.

llvm-svn: 283787
2016-10-10 18:12:53 +00:00
Rafael Espindola 8db87291ef Internalize common variables.
Before this lld was always creating common symbols itself. It worked,
but prevented them from being internalized when possible.

Now it preserves common symbols is the bitcode and they are internalized.

Fixes pr30184.

llvm-svn: 280242
2016-08-31 13:42:08 +00:00
Davide Italiano 35af5b3d21 [LTO] Fix the logic for dropping unnamed_addr.
Differential Revision:  https://reviews.llvm.org/D24037

llvm-svn: 280144
2016-08-30 20:15:03 +00:00
Rafael Espindola 7ce1bc71f4 Document an interesting LTO case.
This is a reduction from the only symbol in a build of clang that the
gold plugin internalizes but lld does not.

llvm-svn: 272845
2016-06-15 21:33:11 +00:00
Peter Collingbourne 5079f3b727 Update LLD for D20550.
Differential Revision: http://reviews.llvm.org/D20704

llvm-svn: 270968
2016-05-27 05:21:45 +00:00
Davide Italiano 334fce92d9 [LTO] Don't crash on old DebugInfo.
Drop them and produce a graceful warning instead.

llvm-svn: 269149
2016-05-11 01:07:22 +00:00
Rafael Espindola cceacd7113 Don't depend on lld creating relocations in ro segments.
We currently don't do a good job of diagnosing inputs that would require
dynamic relocations to be applied to read only segments.

I am about to improve lld in that area, but unfortunately we developed
tests that depend on the current behavior.

To make clear what is actually changing, this first patch just updates
tests to not depend on the current behavior. In most cases this just
means using a rw section instead of a ro one, but that unfortunately
changes many addresses.

llvm-svn: 268145
2016-04-30 00:49:10 +00:00
Davide Italiano 9f8efffe29 [LTO] Create Undefined Bitcode symbol when we drop a comdat member.
Differential Revision:  http://reviews.llvm.org/D19389

llvm-svn: 267181
2016-04-22 18:26:33 +00:00
Rafael Espindola 4d480ed545 Internalize linkonce_odr more often.
Since there is a copy in every translation unit that uses them, they can
be omitted from the symbol table if the address is not significant.

This still doesn't catch as many cases as the gold plugin. The
difference is that we check canBeOmittedFromSymbolTable in each file and
use lazy loading which limits what it can do. Gold checks it in the merged file.

I think the correct way of getting the same results as gold is just to
cache in the IR the result of canBeOmittedFromSymbolTable.

llvm-svn: 267063
2016-04-21 21:44:25 +00:00
Davide Italiano afd1b06d8e [LTO] Another couple of tests for cases we already get right.
-> Drop linkage when converting to decl
-> Handling of unnamed_addr.

llvm-svn: 266954
2016-04-21 04:50:08 +00:00
Davide Italiano bcc7f617cd [LTO] Another type merge test.
llvm-svn: 266899
2016-04-20 18:38:09 +00:00
Davide Italiano a479b968e9 [LTO] Add a test to ensure we handle basic type merging correctly.
llvm-svn: 266896
2016-04-20 18:10:25 +00:00
Rui Ueyama 029d89ee57 Fix another crash bug in --start-lib.
The previous fix didn't work for bitcode files. This patch fixes
the remaining issue.

llvm-svn: 265854
2016-04-08 21:38:22 +00:00
Rui Ueyama f8baa66056 ELF: Implement --start-lib and --end-lib
start-lib and end-lib are options to link object files in the same
semantics as archive files. If an object is in start-lib and end-lib,
the object is linked only when the file is needed to resolve
undefined symbols. That means, if an object is in start-lib and end-lib,
it behaves as if it were in an archive file.

In this patch, I introduced a new notion, LazyObjectFile. That is
analogous to Archive file type, but that works for a single object
file instead of for an archive file.

http://reviews.llvm.org/D18814

llvm-svn: 265710
2016-04-07 19:24:51 +00:00
Rafael Espindola f47657301b Change the type hierarchy for undefined symbols.
We have to differentiate undefined symbols from bitcode and undefined
symbols from other sources.

Undefined symbols from bitcode should not inhibit the symbol being
internalized. Undefined symbols from other sources should.

llvm-svn: 265536
2016-04-06 13:22:41 +00:00
Rafael Espindola 5cea969dca Fix another case of propagating IsUsedRegularObj.
I have an idea on how to clean this up, but lets get the tests passing
first.

llvm-svn: 265374
2016-04-05 01:38:43 +00:00
Peter Collingbourne e8afa4971c ELF: Preserve MustBeInDynSym for bitcode symbols.
Make sure to copy the MustBeInDynSym field when replacing shared symbols with
bitcode symbols, and when replacing bitcode symbols with regular symbols
in addCombinedLtoObject. Fixes interposition of DSO symbols with bitcode
symbols in the main executable.

Differential Revision: http://reviews.llvm.org/D18780

llvm-svn: 265371
2016-04-05 00:47:55 +00:00
Davide Italiano 4fda708624 [LTO] Fix symbols which were internalized incorrectly.
If a symbol is defined in an archive, when we replace its body
the isUsedInRegularObj wasn't set correctly. Internalize makes
its decision based on that bit so we ended up internalizing
symbols that we shouldn't (because they're referenced).
This should fix. Thanks to Peter and Rafael for discussion
and help diagnosing the issue!

Found during LTO of unittests.

llvm-svn: 265208
2016-04-02 02:10:40 +00:00
Davide Italiano bbaf5e0acf [LTO] Add a test to ensure we treat externally available symbols correctly.
We already get it right, but there was no coverage for it.

llvm-svn: 264925
2016-03-30 21:01:14 +00:00
Davide Italiano 04d6aa2b38 [LTO] Include in .symtab/.dynsym symbols introduced by optimizations.
Some optimizations, e.g. SimplifyLibCalls, can replace functions with
others as part of the lowering, e.g. printf => puts.
The new symbols don't have the isUsedInRegularObj flag set so they
don't get included in the final symbol table (and dynamic symbol
table), and the dynamic linker gets confused. Include  them as a fix.

Differential Revision: http://reviews.llvm.org/D18357

llvm-svn: 264688
2016-03-29 00:15:52 +00:00
Davide Italiano bcd660a908 [LTO] Keep linkonce symbols when required.
Similarly to how we do with linkonce_odr symbols already, but
change their linkage to weak.

llvm-svn: 264181
2016-03-23 18:41:48 +00:00
Davide Italiano d4c2a03c32 [LTO] Keep linkonce_odr symbols when appropriate.
Ensure we keep the symbol we need to before it reaches
the Writer (and hit an assertion), changing its linkage
from linkonce_odr to weak. For a more detailed description
of the problem, see PR19901 where a similar problem was
fixed for the gold plugin. Thanks to Rafael for providing
a testcase.

llvm-svn: 264111
2016-03-22 22:31:34 +00:00
Sean Silva 35ef3d95eb [lto] Add beginning of -save-temps option.
Summary:
This is useful for debugging issues with LTO.
The option follows the analogous option in ld64 and the gold plugin (per
Rafael's suggestion).

For starters, this only dumps the combined bitcode file.
In a future patch I will add dumping for the .o file.

The naming of the output follows ld64's convention which is slightly more
consistent IMO (consistent `.lto.<extension>` for all the files).

Reviewers: rafael, ruiu

Subscribers: joker.eph, Bigcheese, llvm-commits

Differential Revision: http://reviews.llvm.org/D18006

llvm-svn: 263055
2016-03-09 20:01:08 +00:00
Sean Silva 31a5ab9e3b [lto] Record whether a variable is TLS.
Summary:

Reviewers: rafael

Subscribers: Bigcheese, llvm-commits, joker.eph

Differential Revision: http://reviews.llvm.org/D17974

llvm-svn: 262975
2016-03-09 00:47:47 +00:00
Rafael Espindola 37bcaac179 Add support for common symbols.
llvm-svn: 262848
2016-03-07 19:15:57 +00:00