Commit Graph

157 Commits

Author SHA1 Message Date
Rafael Espindola aca2afcc55 Don't depend on these symbols being implicitly global.
This might change in llvm-mc and it is nice to be explicit in a test.

llvm-svn: 308506
2017-07-19 18:24:38 +00:00
Rafael Espindola 3ddf2110d5 Bring back r307364.
In addition this includes a change to prefer symbols with a default
version @@ over unversioned symbols.

Original commit message:

[ELF] - Handle symbols with default version early.

This fixes last testcase provided in PR28414.
In short issue is next: when we had X@@Version symbol in object A,
we did not resolve it to X early. Then when in another object B
we had reference to undefined X, symbol X from archive was fetched.
Since both archive and object A contains another symbol Z, duplicate
symbol definition was triggered as a result.

Correct behavior is to use X@@Version from object A instead and do not fetch
any symbols from archive.

Differential revision: https://reviews.llvm.org/D35059

llvm-svn: 308492
2017-07-19 16:45:05 +00:00
Rui Ueyama 0e0369e535 Revert r307364: [ELF] - Handle symbols with default version early.
This reverts commit r307364 because that change is likely to have
caused https://bugs.llvm.org/show_bug.cgi?id=33820.

llvm-svn: 308239
2017-07-18 00:33:14 +00:00
Rui Ueyama 8d8916d1dd Fix tests for .ctors/.dtors.
They are supposed to contain pointers, so .byte wasn't quite right.

llvm-svn: 308214
2017-07-17 20:42:52 +00:00
George Rimar 638e8a405d [ELF] - Remove dependency on precompiled inputs from -gdb-index testcases.
Previously we used precompiled objects in gdb-index.s and
debug-gnu-pubnames.s testcases. We can avoid that.

Differential revision: https://reviews.llvm.org/D35360

llvm-svn: 308005
2017-07-14 08:26:44 +00:00
Rafael Espindola d3fc0c91e3 Bring back InVersionScript.
We were producing bogus warnings without it.

llvm-svn: 307820
2017-07-12 17:49:17 +00:00
George Rimar d92e1286ed [ELF] - Fix handling of weak symbols from static library when using version script.
When version script was used, binding opf undefined weak symbols sometimes
was calculated as STB_LOCAL, making them non-preemtible what
broke correct relocations handling logic for them.

Fixes PR33738.

Differential revision: https://reviews.llvm.org/D35263

llvm-svn: 307767
2017-07-12 11:09:46 +00:00
George Rimar 4a9cfc8267 [ELF] - Fix functionality treating IFunc definitions in DSOs as functions.
It was intially implemented in D19517 but then broken.
Patch fixes PR33707, testcase is based on PR's case.

Differential revision: https://reviews.llvm.org/D35119

llvm-svn: 307652
2017-07-11 11:40:59 +00:00
George Rimar 85e9216e8c [ELF] - Handle symbols with default version early.
This fixes last testcase provided in PR28414.
In short issue is next: when we had X@@Version symbol in object A,
we did not resolve it to X early. Then when in another object B
we had reference to undefined X, symbol X from archive was fetched.
Since both archive and object A contains another symbol Z, duplicate
symbol definition was triggered as a result.

Correct behavior is to use X@@Version from object A instead and do not fetch
any symbols from archive.

Differential revision: https://reviews.llvm.org/D35059

llvm-svn: 307364
2017-07-07 08:29:51 +00:00
Rafael Espindola cf00d4374e Fix PR33635.
This is a semantic revert of r306036.

We have to change the names, otherwise dynamic relocations will point
to the wrong name.

llvm-svn: 307110
2017-07-05 00:43:18 +00:00
George Rimar dbe843d602 [ELF] - Do not set st_size field of SHT_UNDEF symbols.
This fixes PR33598.

Size field for undefined symbols is not significant.
Setting it to fixed value, like zero, may be useful though.

For example when we have 2 DSO's, like in this PR, if lower level DSO may
change slightly (in part of some symbol's st_size)  and higher-level DSO is
rebuilt, then tools that monitoring checksum of high level DSO file can notice
it and trigger cascade of some other unnecessary actions. 
If we set st_size to zero, that can be avoided.

Differential revision: https://reviews.llvm.org/D34673

llvm-svn: 306526
2017-06-28 09:51:33 +00:00
Rui Ueyama d1f8b8162b Implement the --exclude-libs option.
The --exclude-libs option is not a popular option, but at least some
programs in Android depend on it, so it's worth to support it.

Differential Revision: https://reviews.llvm.org/D34422

llvm-svn: 305920
2017-06-21 15:36:24 +00:00
Rui Ueyama f9f69548a9 Allow the GNU gold-style nonstandard SHT_GROUP section.
The ELF standard defines that the SHT_GROUP section as follows:

 - its sh_link has the symbol index, and
 - the symbol name is used to uniquify section groups.

Object files created by GNU gold does not seem to comply with the
standard. They have this additional rule:

 - if the symbol has no name and a STT_SECTION symbol, a section
   name is used instead of a symbol name.

If we don't do anything for this, the linker fails with a mysterious
error message if input files are generated by gas. It is unfortunate
but I think we need to support it.

Differential Revision: https://reviews.llvm.org/D34064

llvm-svn: 305218
2017-06-12 18:46:33 +00:00
Peter Collingbourne bfd5113ca1 ELF: Teach ICF about relocations referring to merge input sections.
Relocations referring to merge sections are considered equal if they
resolve to the same offset in the same output section.

Differential Revision: https://reviews.llvm.org/D34094

llvm-svn: 305177
2017-06-12 00:05:54 +00:00
George Rimar 8cde9a7e77 [ELF] - Allow multiple comdats when producing relocatable output.
Previously LLD would fail for case when there are multiple comdats and -r.

That happened because it merged all ".group" (SHT_GROUP) sections into single
output, producing broken result. Such sections may have similar name, alignment and flags
and other properties. We need to produce separate output section for each such input one.

Differential revision: https://reviews.llvm.org/D33643

llvm-svn: 304769
2017-06-06 06:38:32 +00:00
Petr Hosek ffa786f465 [lld][ELF]Add option to make .dynamic read only
The .dynamic section of an ELF almost doesn't need to be written to with
the exception of the DT_DEBUG entry. For several reasons having a read
only .dynamic section would be useful. This change adds the -z keyword
"rodynamic" which forces .dynamic to be read-only. In this case DT_DEBUG
will not be emited.

Patch by Jake Ehrlich

Differential Revision: https://reviews.llvm.org/D33251

llvm-svn: 304024
2017-05-26 19:12:38 +00:00
George Rimar b4081bb0ab [ELF] - Stop support of DF_STATIC_TLS flag.
This reverts changes introduced in r302414 "[ELF] - Set DF_STATIC_TLS flag for i386 target."

Because DF_STATIC_TLS does not look to be used by glibc or anything else.

llvm-svn: 302884
2017-05-12 08:04:58 +00:00
George Rimar 1564122b05 [ELF] - Set DF_STATIC_TLS flag for i386 target.
This is PR32437.

DF_STATIC_TLS
If set in a shared object or executable, this flag instructs the 
dynamic linker to reject attempts to load this file dynamically. 
It indicates that the shared object or executable contains code 
using a static thread-local storage scheme. Implementations need 
not support any form of thread-local storage.

Patch checks if IE/LE relocations were used to check if code uses
static model. If so it sets the DF_STATIC_TLS flag.

Differential revision: https://reviews.llvm.org/D32354

llvm-svn: 302414
2017-05-08 10:24:38 +00:00
Rafael Espindola 5e20c75e3a Handle mixed strong and weak undefined symbols.
We were ignoring strong undefined symbols if they followed weak ones.

Fixes pr32899.

llvm-svn: 302065
2017-05-03 18:40:27 +00:00
Rafael Espindola a8a1a4fc30 Avoid empty .eh_frame sections.
Strip on OpenBSD does not correctly handle an empty .eh_frame section
and produces broken binaries in that case. Currently lld creates such
an empty .eh_frame section, despite the fact that the OpenBSD crtend.o
explicitly inserts a terminator. The Linux LSB "standard":

https://refspecs.linuxfoundation.org/LSB_5.0.0/LSB-Core-generic/LSB-Core-generic/ehframechpt.html#EHFRAME

explicitly says that

    The .eh_frame section shall contain 1 or more Call Frame Information (CFI) records.

This diff includes a test that specifically tests the issue I'm seeing
on OpenBSD.

Patch by Mark Kettenis!

llvm-svn: 301931
2017-05-02 15:45:31 +00:00
Rui Ueyama c1d043c40a Replace a binary .so with a text .s.
Since LLD is now able to take version scripts, we no longer
have to keep a pre-generated binary file for a test.

llvm-svn: 301279
2017-04-24 23:51:18 +00:00
George Rimar e7bf968803 [ELF] - Stop producing broken output for R_386_GOT32[X] relocations.
Previously we silently produced broken output for R_386_GOT32X/R_386_GOT32 
relocations if they were used to compute the address of the symbol’s global
offset table entry without base register when position-independent code is disabled.

Situation happened because of recent ABI changes. Released ABI mentions that
R_386_GOT32X can be calculated in a two different ways (so we did not follow ABI here 
before this patch), but draft ABI also mentions R_386_GOT32 relocation here. 
We should use the same calculations for both relocations.

Problem is that we always calculated them as G + A - GOT (offset from end of GOT),
but for case when PIC is disabled, according to i386 ABI calculation should be G + A,
what should produce just an address in GOT finally.

ABI: https://github.com/hjl-tools/x86-psABI/wiki/intel386-psABI-draft.pdf (p36, p60).
llvm-svn: 299812
2017-04-08 06:14:14 +00:00
George Rimar 1ab9cf49d0 [ELF] - Recommit "[ELF] - Make Bss and BssRelRo sections to be synthetic ()."
Was fixed, details on review page.

Original commit message:

That removes CopyRelSection class completely, making
Bss/BssRelRo to be just regular synthetics.

This is splitted from D30541 and polished.
Difference from D30541 that all logic of SharedSymbol
converting to DefinedRegular was removed for now and
probably will be posted as separate patch.

Differential revision: https://reviews.llvm.org/D30892

llvm-svn: 298062
2017-03-17 10:14:53 +00:00
Rafael Espindola d3c22f08b3 Don't create copy relocs or dummy plt's if given -z notext.
Being passed -z notext is a pretty strong indication that the user is
OK with text relocations. This is not the same behavior as bfd, but
bfd defaults to -z notext, so it has to try to avoid text relocations
and use them as a last resort.

llvm-svn: 297789
2017-03-14 22:50:07 +00:00
Petr Hosek b27bb59a5d [ELF] Ignore R_*_NONE relocs when relocating non-alloc sections
We shouldn't report an error for R_*_NONE relocs since we're emitting
them when writing relocations to discarded sections.

Differential Revision: https://reviews.llvm.org/D30279

llvm-svn: 295936
2017-02-23 06:22:28 +00:00
Rafael Espindola 195fba2967 Fix checks for R_386_8 and R_386_16.
Results created by these relocations are expected to be zero extended
at runtime.

llvm-svn: 294988
2017-02-13 21:29:56 +00:00
Rafael Espindola d6e9ef7e21 Implement R_X86_64_16.
It is used by qemu.

llvm-svn: 294965
2017-02-13 16:21:34 +00:00
George Rimar 60ca31dff8 [ELF] - Simplify i386-ps8.s testcase.
Removes dependency on second input file.

llvm-svn: 294178
2017-02-06 09:25:56 +00:00
Rafael Espindola 0b034d6f25 Fix -r when the input has a relocation with no symbol.
Should fix a few freebsd packages with dtrace.

llvm-svn: 293177
2017-01-26 14:09:18 +00:00
George Rimar f242ffa095 [ELF] - Implemented support for R_386_PC8/R_386_8 relocations.
These relocations are used in linux kernel.

Differential revision: https://reviews.llvm.org/D28094

llvm-svn: 293054
2017-01-25 13:36:49 +00:00
Peter Collingbourne dbd8d9b5a2 ELF: Fix ICF crash on absolute symbol relocations.
If two sections contained relocations to absolute symbols with the same
value we would crash when trying to access their sections. Add a check that
both symbols point to sections before accessing their sections, and treat
absolute symbols as equal if their values are equal.

Differential Revision: https://reviews.llvm.org/D28935

llvm-svn: 292578
2017-01-20 04:58:12 +00:00
Rafael Espindola 2c87688c70 Also define 'end' if it is present in a .so.
I don't know of anything using it, but we should handle it like _end.

llvm-svn: 292513
2017-01-19 19:51:02 +00:00
Rafael Espindola b92e99cc1e Create _end symbol even if a .so defines it.
The freebsd sbrk implementation uses _end to find the initial value of
brk, so it has to be defined in the main binary.

This should fix the emacs build.

llvm-svn: 292512
2017-01-19 19:43:34 +00:00
Peter Collingbourne ae30386fb3 ELF: Add support for relocation type R_X86_64_8.
Although this relocation type is not part of the x86-64 psABI, I intend to
use it internally as part of the ThinLTO implementation.

Differential Revision: https://reviews.llvm.org/D28841

llvm-svn: 292330
2017-01-18 02:20:53 +00:00
Rafael Espindola 1ebfc59c89 Implement -Map.
The format is not exactly the same as the one in bfd since bfd always
follows a linker script and prints it along.

llvm-svn: 291958
2017-01-13 21:05:46 +00:00
George Rimar 57b0e6a5c9 [ELF] - Explicitly list supported relocations for x86 target.
Previously some value was returned by default for relocations by getRelExpr(),
even if relocation actually was not supported.

This is orthogonal alternative to D28094.
Instead of implementing probably useless R_386_PC8/R_386_8 relocations,
this patch uses them in a testcase to demonstrate what happens
when LLD mets unsupported relocations.

Patch passes all testcases and changes logic only for x86.

Differential revision: https://reviews.llvm.org/D28516

llvm-svn: 291658
2017-01-11 08:29:52 +00:00
Peter Collingbourne feb6629d6d ELF: Reserve space for copy relocations of read-only symbols in relro.
When reserving copy relocation space for a shared symbol, scan the DSO's
program headers to see if the symbol is in a read-only segment. If so,
reserve space for that symbol in a new synthetic section named .bss.rel.ro
which will be covered by the relro program header.

This fixes the security issue disclosed on the binutils mailing list at:
https://sourceware.org/ml/libc-alpha/2016-12/msg00914.html

Differential Revision: https://reviews.llvm.org/D28272

llvm-svn: 291524
2017-01-10 01:21:50 +00:00
Simon Atanasyan 86dc60d8d4 [ELF][MIPS] Allow .MIPS.abiflags larger than one Elf_Mips_ABIFlags struct
Older versions of BFD generate libraries with .MIPS.abiflags that only
concatenate the individual .MIPS.abiflags sections instead of merging.

Patch by Alexander Richardson.

Differential revision: https://reviews.llvm.org/D27770

llvm-svn: 290237
2016-12-21 05:31:57 +00:00
Peter Smith 532bc984f5 [ELF] Accept first SHT_ARM_ATTRIBUTES section
The eglibc library, as used by Ubuntu 14.04 requires the presence of an
SHT_ARM_ATTRIBUTES section in for the purposes of checking hard/soft float
compatibility when dlopen() is used. Unfortunately when the section is not
present dlopen() fails with a generic could not find file message.
    
This change makes lld keep the first .ARM.attributes section that it
encounters and propagates it to the output. This is not a complete
SHT_ARM_ATTRIBUTES implementation, that would involve reading the contents
of the section and joining each individual attribute. It should suffice
for a homogenous build all libraries and executables on the same system
with a compatible set of command line options.

Differential revision: https://reviews.llvm.org/D27718

llvm-svn: 289642
2016-12-14 10:36:12 +00:00
Peter Smith baffdb8bc2 [ELF] ifunc implementation using synthetic sections
This change introduces new synthetic sections IpltSection, IgotPltSection
that represent the ifunc entries that would previously have been put in
the PltSection and the GotPltSection. The separation makes sure that
the R_*_IRELATIVE relocations are placed after the non R_*_IRELATIVE
relocations, which permits ifunc resolvers to know that the .got.plt
slots will be initialized prior to the resolver being called.

A secondary benefit is that for ARM we can move the IgotPltSection and its
dynamic relocations to the .got and .rel.dyn as the ARM glibc expects all
the R_*_IRELATIVE relocations to be in the .rel.dyn

Differential revision: https://reviews.llvm.org/D27406

llvm-svn: 289045
2016-12-08 12:58:55 +00:00
George Rimar 92c88a4f76 [ELF] - Print absolute file name in errors when possible.
Currently LLD prints basename of source file name in error messages,
for example:
$ mkdir foo
$ echo 'void _start(void) { foobar(); }' > foo/bar.c
$ gcc -g -c foo/bar.c
$ bin/ld.lld -o out bar.o 
bin/ld.lld: error: bar.c:1: undefined symbol 'foobar'
$
This should say:
bin/ld.lld: error: foo/bar.c:1: undefined symbol 'foobar'

This is PR31299

Differential revision: https://reviews.llvm.org/D27506

llvm-svn: 288966
2016-12-07 19:42:25 +00:00
Rafael Espindola e004d4bfc2 Don't crash trying to write an 0 addend.
For preemptable symbols the dynamic linker does all the work. Trying
to compute the addend is at best wasteful and can also lead to crashes
in cases of programs that uses tls but doesn't define any tls
variables.

llvm-svn: 288803
2016-12-06 12:19:24 +00:00
Rafael Espindola 27004d336f Ignone SHF_INFO_LINK.
Some elf producers (dtrace) put this flag in relocation sections and
some (MC) don't. If we don't ignore the flag we end up with multiple
relocation sections poiting to the same section, which we don't
support.

llvm-svn: 288585
2016-12-03 15:26:18 +00:00
Rui Ueyama 83ec681a5c Removed a wrong assertion about non-colorable sections.
The assertion asserted that colorable sections can never have
a reference to non-colorable sections, but that was simply wrong.
They can have references to non-colorable sections. If that's the
case, referenced sections must be the same in terms of pointer
comparison.

llvm-svn: 288511
2016-12-02 17:23:58 +00:00
Rui Ueyama d14743e17f Better formatting.
If a line is too long, its error message becomes hard to read.

llvm-svn: 287739
2016-11-23 05:14:01 +00:00
Eugene Leviant 91972d7f9d [ELF] Attempt to fix Windows buidbot
llvm-svn: 287538
2016-11-21 13:57:50 +00:00
George Rimar 7beff42f8f [ELF] - Do not create reserved symbols in case of relocatable output.
This patch stops creating symbols like __ehdr_start, 
_end/_etext_edata,__tls_get_addr when using -r.

This fixes PR30984.

Differential revision: https://reviews.llvm.org/D26600

llvm-svn: 286941
2016-11-15 08:19:02 +00:00
George Rimar 463984d4bf [ELF] - Better diagnostic for relative relocation to an absolute value error.
Patch adds a filename to that error message.

I faced next error when debugged one of FreeBSD port:
error: relocation R_X86_64_PLT32 cannot refer to absolute symbol __tls_get_addr

error message was poor and this patch improves it to show the locations 
of symbol declaration and using.

Differential revision: https://reviews.llvm.org/D26508

llvm-svn: 286940
2016-11-15 08:07:14 +00:00
Eugene Leviant 825e538559 [ELF] Better error reporting for duplicate symbol
Differential revision: https://reviews.llvm.org/D26397

llvm-svn: 286244
2016-11-08 16:26:32 +00:00
Simon Atanasyan 9e0297b8bc [ELF][MIPS] N32 ABI support
In short the patch introduces support for linking object file conform
MIPS N32 ABI [1]. This ABI is similar to N64 ABI but uses 32-bit
pointer size.

The most non-trivial requirement of this ABI is one more relocation
packing format. N64 ABI puts multiple relocation type into the single
relocation record. The N32 ABI uses series of successive relocations
with the same offset for this purpose. In this patch, new function
`mergeMipsN32RelTypes` handle this case and "convert" N32 relocation to
the N64 relocation so the rest of the code keep unchanged.

For now, linker does not support series of relocations applied to sections
without SHF_ALLOC bit. Probably later I will add the support or insert
some sort of assert into the `relocateNonAlloc` routine to catch this
case.

[1] ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/MIPS-N32-ABI-Handbook.pdf

Differential revision: https://reviews.llvm.org/D26298

llvm-svn: 286052
2016-11-05 22:58:01 +00:00