Commit Graph

1425 Commits

Author SHA1 Message Date
Rui Ueyama 3b6cd2c602 Show a proper error message if output file is too large.
At least on Linux, if a file size given to FileOutputBuffer is greater
than 2^63, it fails with "Invalid argument" error, which is not a
user-friendly error message. With this patch, lld prints out "output
file too large" instead.

llvm-svn: 348153
2018-12-03 17:42:57 +00:00
George Rimar 89230f7bc2 [LLD][ELF] - Remove the excessive condition. NFC.
There is no need to check that In.DynSymTab != nullptr,
because `includeInDynsym` already checks for `!Config->HasDynSymTab`
and `HasDynSymTab` is the pre-condition for In.DynSymTab creation.

llvm-svn: 348143
2018-12-03 14:44:02 +00:00
Peter Smith fd8aeb2c2a [LLD][ELF] Error if _GLOBAL_OFFSET_TABLE_ is defined in input objects
The _GLOBAL_OFFSET_TABLE_ is a linker defined symbol that is placed at
some location relative to the .got, .got.plt or .toc section. On some
targets such as Arm the correctness of some code sequences using a
relocation to _GLOBAL_OFFSET_TABLE_ depend on the value of the symbol
being in the linker defined place. Follow the ld.gold example and give
a multiple symbol definition error. The ld.bfd behaviour is to ignore the
definition in the input object and redefine it, which seems like it could
be more surprising.

fixes pr39587

Differential Revision: https://reviews.llvm.org/D54624

llvm-svn: 347854
2018-11-29 11:18:07 +00:00
George Rimar 94a16cb611 [ELF] - Make SymbolTable::addDefined return Defined.
Now it returns Symbol. This should be NFC that
avoids doing cast at the caller's sides.

Differential revision: https://reviews.llvm.org/D54627

llvm-svn: 347455
2018-11-22 11:40:08 +00:00
Sean Fertile 614dc11ca8 [PPC64] Long branch thunks.
On PowerPC64, when a function call offset is too large to encode in a call
instruction the address is stored in a table in the data segment. A thunk is
used to load the branch target address from the table relative to the
TOC-pointer and indirectly branch to the callee. When linking position-dependent
code the addresses are stored directly in the table, for position-independent
code the table is allocated and filled in at load time by the dynamic linker.

For position-independent code the branch targets could have gone in the .got.plt
but using the .branch_lt section for both position dependent and position
independent binaries keeps it consitent and helps keep this PPC64 specific logic
seperated from the target-independent code handling the .got.plt.

Differential Revision: https://reviews.llvm.org/D53408

llvm-svn: 346877
2018-11-14 17:56:43 +00:00
Rui Ueyama 4c06a6cc90 Rename warnUnorderableSymbol maybeWarnUnorderableSymbol because the function doesn't always emit a warning.
llvm-svn: 345393
2018-10-26 15:07:12 +00:00
Rui Ueyama 444363e931 Do not call computeIsPreemptible() if its result is discarded. NFC.
llvm-svn: 345208
2018-10-24 22:15:32 +00:00
Rui Ueyama 4664280a9c Add more blank lines so that code doesn't look too dense. NFC.
llvm-svn: 345205
2018-10-24 21:59:58 +00:00
Rui Ueyama 6e33f7ac66 Add a comment for PPC64 .toc and GNU relro.
llvm-svn: 345204
2018-10-24 21:59:48 +00:00
Rui Ueyama aa2948776a Include input section name and output section name in an error message.
Differential Revision: https://reviews.llvm.org/D53645

llvm-svn: 345172
2018-10-24 18:15:40 +00:00
Rui Ueyama 8d76024916 Refactor assignFileOffsets. NFC.
llvm-svn: 345154
2018-10-24 15:47:46 +00:00
Rui Ueyama 6d26ed92cc Split a function. NFC.
llvm-svn: 345143
2018-10-24 14:24:01 +00:00
Rui Ueyama 6e763a36c6 Add parenthese around a bitand.
llvm-svn: 345139
2018-10-24 13:44:51 +00:00
Rui Ueyama ee2b61cfd3 Make a local variable scope narrower. NFC.
llvm-svn: 345138
2018-10-24 13:42:33 +00:00
Martin Storsjo c3095ace86 [ELF] Remove a superfluous semicolon, fixing warnings. NFC.
llvm-svn: 345116
2018-10-24 07:42:06 +00:00
Rui Ueyama 5a30177ef6 Factor out code to a new function. NFC.
llvm-svn: 345088
2018-10-23 22:03:33 +00:00
Rui Ueyama edc3201b11 Simplify. NFC.
A higher order function `applySyntehtic` can be replaced with a simpler function.

llvm-svn: 345081
2018-10-23 21:17:00 +00:00
Rui Ueyama 660e8721a9 Remove a global variable that is set but not used.
llvm-svn: 345080
2018-10-23 21:00:28 +00:00
Rui Ueyama 29d8639732 Add a comment.
llvm-svn: 345062
2018-10-23 17:52:44 +00:00
Rui Ueyama 42ab6c53f8 Remove a global variable that we can live without.
Out::DebugInfo was used only by GdbIndex class to determine if
we need to create a .gdb_index section, but we can do the same
check without it.

Added a test that this patch doesn't change the existing behavior.

llvm-svn: 345058
2018-10-23 17:39:43 +00:00
Dimitry Andric ad5aab8ddb Don't mess up RelIplt symbols during relocatable processing
Summary:
During upgrading of the FreeBSD source tree with lld 7.0.0, I noticed
that it started complaining about `crt1.o` having an "index past the
end of the symbol table".

Such a symbol table looks approximately like this, viewed with `readelf
-s` (note the `Ndx` field being messed up):

```
Symbol table '.symtab' contains 4 entries:
   Num:    Value  Size Type    Bind   Vis      Ndx Name
     0: 00000000     0 NOTYPE  LOCAL  DEFAULT  UND
     1: 00000000     0 SECTION LOCAL  DEFAULT    1
     2: 00000000     0 NOTYPE  WEAK   HIDDEN  RSV[0xffff] __rel_iplt_end
     3: 00000000     0 NOTYPE  WEAK   HIDDEN  RSV[0xffff] __rel_iplt_start
```

At first, it seemed that recent ifunc relocation work had caused this:
<https://reviews.freebsd.org/rS339351>, but it turned out that it was
due to incorrect processing of the object files by lld, when using `-r`
(a.k.a. --relocatable).

Bisecting showed that rL324421 ("Convert a use of Config->Static") was
the commit where this new behavior began.  Simply reverting it solved
the issue, and the `__rel_iplt` symbols had an index of `UND` again.

Looking at Rafael's commit message, I think he simply missed the
possibility of `--relocatable` being in effect, so I have added an
additional check for it.

I also added a simple regression test case.

Reviewers: grimar, ruiu, emaste, espindola

Reviewed By: ruiu

Subscribers: arichardson, krytarowski, llvm-commits

Differential Revision: https://reviews.llvm.org/D53515

llvm-svn: 345002
2018-10-23 05:53:15 +00:00
Alexander Richardson 39adc6df0d Add an addAbsolute static function to Writer.cpp
Summary:
SymbolTable::addAbsolute() was removed in rL344305.
To me this is more readable than the lambda named `Add` and in our
out-of-tree CHERI target we use addAbsolute() in another function.

Reviewers: ruiu, espindola

Reviewed By: ruiu

Subscribers: kristina, emaste, llvm-commits

Differential Revision: https://reviews.llvm.org/D53393

llvm-svn: 344842
2018-10-20 11:12:50 +00:00
Rui Ueyama b0d8502049 Remove SymbolTable::addAbsolute().
addAbsolute() could be implemented as a non-member function.

llvm-svn: 344305
2018-10-11 22:15:41 +00:00
Rui Ueyama 2600e0946b Rename SymbolTable::addRegular -> SymbolTable::addDefined.
We have addAbsolute, addBitcode, addCommon, etc. addRegular looked a
bit inconsistent.

llvm-svn: 344294
2018-10-11 20:43:01 +00:00
Fangrui Song dbaeec6892 [ELF] llvm::sort(C.begin(), C.end(), ...) -> llvm::sort(C, ...)
Summary: The convenience wrapper in STLExtras is available since rL342102.

Reviewers: ruiu, espindola

Subscribers: emaste, arichardson, mgrang, llvm-commits

Differential Revision: https://reviews.llvm.org/D52569

llvm-svn: 343146
2018-09-26 20:54:42 +00:00
Rui Ueyama 12ef7a9575 De-template VersionDefinitionSection. NFC.
When we write a struct to a mmap'ed buffer, we usually use
write16/32/64, but we didn't for VersionDefinitionSection, so
we needed to template that class.

llvm-svn: 343024
2018-09-25 20:37:51 +00:00
Rui Ueyama 4e247522ac Reset input section pointers to null on each linker invocation.
Previously, if you invoke lld's `main` more than once in the same process,
the second invocation could fail or produce a wrong result due to a stale
pointer values of the previous run.

Differential Revision: https://reviews.llvm.org/D52506

llvm-svn: 343009
2018-09-25 19:26:58 +00:00
Rui Ueyama 180cd0717f Make a member function non-member. NFC.
Non-member functions are generally preferred over member functions
because it is clear that non-member functions don't depend on an
internal state of an object.

llvm-svn: 342695
2018-09-20 22:58:00 +00:00
Ryan Prichard 1c33d14bcd [ELF] Set Out::TlsPhdr earlier for encoding packed reloc tables
Summary:
For --pack-dyn-relocs=android, finalizeSections calls
LinkerScript::assignAddresses and
AndroidPackedRelocationSection::updateAllocSize in a loop,
where assignAddresses lays out the ELF image, then updateAllocSize
determines the size of the Android packed relocation table by encoding it.
Encoding the table requires knowing the values of relocation addends.

To get the addend of a TLS relocation, updateAllocSize can call getSymVA
on a TLS symbol before setPhdrs has initialized Out::TlsPhdr, producing an
error:

    <file> has an STT_TLS symbol but doesn't have an SHF_TLS section

Fix the problem by initializing Out::TlsPhdr immediately after the program
headers are created. The segment's p_vaddr field isn't initialized until
setPhdrs, so use FirstSec->Addr, which is what setPhdrs would use.
FirstSec will typically refer to the .tdata or .tbss output section, whose
(tentative) address was computed by assignAddresses.

Android currently avoids this problem because it uses emutls and doesn't
support ELF TLS. This problem doesn't apply to --pack-dyn-relocs=relr
because SHR_RELR only handles relative relocations without explicit addends
or info.

Fixes https://bugs.llvm.org/show_bug.cgi?id=37841.

Reviewers: ruiu, pcc, chh, javed.absar, espindola

Subscribers: emaste, arichardson, llvm-commits, srhines

Differential Revision: https://reviews.llvm.org/D51671

llvm-svn: 342432
2018-09-18 00:24:48 +00:00
Rui Ueyama 10454c4fd5 Style fix.
llvm-svn: 341937
2018-09-11 13:41:58 +00:00
Rui Ueyama 025bb56a86 Always add a .note.GNU-stack section if -r.
With this patch, lld creates a .note.GNU_stack and adds that to an
output file if it is creating a re-linkable object file (i.e. if -r
is given). If we don't do this, and if you use GNU linkers as a final
linker, they create an executable whose stack area is executable,
which is considered pretty bad these days.

Differential Revision: https://reviews.llvm.org/D51400

llvm-svn: 340902
2018-08-29 07:27:09 +00:00
Peter Smith a8656c62f5 [ELF] Add support for Armv5 and Armv6 compatible Thunks
Older Arm architectures do not support the MOVT and MOVW instructions so we
must use an alternative sequence of instructions to transfer control to the
destination.

Assuming at least Armv5 this patch adds support for Thunks that load or add
to the program counter. Note that there are no Armv5 Thumb Thunks as there
is no Thumb branch instruction in Armv5 that supports Thunks. These thunks
will not work for Armv4t (arm7tdmi) as this architecture cannot change state
from using the LDR or ADD instruction.

Differential Revision: https://reviews.llvm.org/D50077

llvm-svn: 340160
2018-08-20 09:37:50 +00:00
George Rimar 88863a5f62 [ELF] - Get rid of SyntheticSection::postThunkContents(). NFCI.
It turns out that postThunkContents() is only used for
sorting symbols in .symtab.

Though we can instead move the logic to SymbolTableBaseSection::finalizeContents(),
postpone calling it and then get rid of postThunkContents completely.

Differential revision: https://reviews.llvm.org/D49547

llvm-svn: 339413
2018-08-10 07:24:18 +00:00
Rui Ueyama 5cd9c6bcd8 Support RISC-V
Patch by PkmX.

This patch makes lld recognize RISC-V target and implements basic
relocation for RV32/RV64 (and RVC). This should be necessary for static
linking ELF applications.

The ABI documentation for RISC-V can be found at:
https://github.com/riscv/riscv-elf-psabi-doc/blob/master/riscv-elf.md.
Note that the documentation is far from complete so we had to figure out
some details from bfd.

The patch should be pretty straightforward. Some highlights:

 - A new relocation Expr R_RISCV_PC_INDIRECT is added. This is needed as
   the low part of a PC-relative relocation is linked to the corresponding
   high part (auipc), see:
   https://github.com/riscv/riscv-elf-psabi-doc/blob/master/riscv-elf.md#pc-relative-symbol-addresses

 - LLVM's MC support for RISC-V is very incomplete (we are working on
   this), so tests are given in objectyaml format with the original
   assembly included in the comments. Once we have complete support for
   RISC-V in MC, we can switch to llvm-as/llvm-objdump.

 - We don't support linker relaxation for now as it requires greater
   changes to lld that is beyond the scope of this patch. Once this is
   accepted we can start to work on adding relaxation to lld.

Differential Revision: https://reviews.llvm.org/D39322

llvm-svn: 339364
2018-08-09 17:59:56 +00:00
George Rimar 4d535299fc [LLD][ELD] - Revert r338959 "[LLD][ELF] - Added file name and a test for case when we fail to write the output."
It broke BB:
http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-ubuntu-fast/builds/34382/steps/test/logs/stdio
http://lab.llvm.org:8011/builders/lld-x86_64-freebsd/builds/21932/steps/test_lld/logs/stdio

llvm-svn: 338960
2018-08-04 13:41:12 +00:00
George Rimar 032ed8f186 [LLD][ELF] - Added file name and a test for case when we fail to write the output.
We did not report the file name and had no test for that case.

llvm-svn: 338959
2018-08-04 12:48:38 +00:00
George Rimar 0fc18331b4 [LLD][ELF] - Removed dead code from rangeToString(). NFC.
This change removes the dead code and makes cosmetic change
showing why it was dead.

llvm-svn: 338957
2018-08-04 10:56:26 +00:00
George Rimar 434341be5b [LLD][ELF] - Fix bug when reporting memory intersections.
rangeToString() takes addres and length,
previously it was called incorrectly.

llvm-svn: 338956
2018-08-04 10:34:52 +00:00
George Rimar 34bdf27eaa [LLD] - Improve handling of AT> linker script commands
Patch by Konstantin Schwarz!

The condition to create a new phdr must also check the usage of "AT>" 
linker script command, and create a new PT_LOAD header if a new LMARegion is used.

This fixes PR38307

Differential revision: https://reviews.llvm.org/D50052

llvm-svn: 338679
2018-08-02 08:07:07 +00:00
Owen Reynolds 035cd8dd75 Test Commit
Removal of extra line

llvm-svn: 338533
2018-08-01 13:16:48 +00:00
David Bolvansky a932cd409b [AArch64] Support execute-only LOAD segments.
Summary:
This adds an LLD flag to mark executable LOAD segments execute-only for AArch64 targets. 

In AArch64 the expectation is that code is execute-only compatible, so this just adds a linker option to enforce this.

Patch by: ivanlozano (Ivan Lozano)

Reviewers: srhines, echristo, peter.smith, eugenis, javed.absar, espindola, ruiu

Reviewed By: ruiu

Subscribers: dokyungs, emaste, arichardson, kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D49456

llvm-svn: 338271
2018-07-30 17:02:46 +00:00
George Rimar 9524dee72e [ELF] - Implement SHT_SYMTAB_SHNDX (.symtab_shndxr) section.
This is relative to https://bugs.llvm.org//show_bug.cgi?id=38119.

SHT_SYMTAB section is able to keep symbols with output section indices
up to 0xff00 (SHN_LORESERVE). But if we have indices that are greater
than that (PR shows that it might happen), we need to use
SHT_SYMTAB_SHNDX extended section. It was not supported by LLD.

Description of the SHT_SYMTAB_SHNDX section is here:
https://docs.oracle.com/cd/E19683-01/817-3677/chapter6-94076/index.html.

Differential revision: https://reviews.llvm.org/D49541

llvm-svn: 338247
2018-07-30 12:39:54 +00:00
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 b9f3ea3e1c [ELF] - Do not produce broken output when amount of sections is > ~65k
This is a part of ttps://bugs.llvm.org//show_bug.cgi?id=38119

We produce broken ELF header now when the number of output sections is >= SHN_LORESERVE (0xff00).

ELF spec says (http://www.sco.com/developers/gabi/2003-12-17/ch4.eheader.html):

e_shnum:
If the number of sections is greater than or equal to SHN_LORESERVE (0xff00), this member has the value zero
and the actual number of section header table entries is contained in the sh_size field of the section header at index 0.
(Otherwise, the sh_size member of the initial entry contains 0.)

e_shstrndx
If the section name string table section index is greater than or equal to SHN_LORESERVE (0xff00), this member has the
value SHN_XINDEX (0xffff) and the actual index of the section name string table section is contained in the sh_link field of
the section header at index 0. (Otherwise, the sh_link member of the initial entry contains 0.)

We did not set these fields correctly earlier. The patch fixes the issue.

Differential revision: https://reviews.llvm.org/D49371

llvm-svn: 337363
2018-07-18 08:44:38 +00:00
George Rimar d55ec633e6 [ELF] - Simplify code. NFC.
Just use getDataAs for taking sections contents.

llvm-svn: 336892
2018-07-12 08:33:02 +00:00
George Rimar d31c478f99 [ELF] - Eliminate dead code. NFC.
Code is dead because caller of the isDuplicateArmExidxSex
(https://github.com/llvm-mirror/lld/blob/master/ELF/Writer.cpp#L1446)

explicitly does not pass sentinel. So no reason to check it.

llvm-svn: 336891
2018-07-12 08:12:08 +00:00
George Rimar bdaffd6c6b [ELF] - Simplify code. NFC.
This looks a bit simpler IMO.

llvm-svn: 336815
2018-07-11 15:23:33 +00:00
George Rimar 1aa8f39dc0 [ELF] - Simplify. NFCI.
It does not look possible to end up with empty Sections
at this place. And this knowledge allows simplifying the code.

llvm-svn: 336814
2018-07-11 15:18:23 +00:00
Rui Ueyama f3731d4e9c Refactor GdbIndexSection. NFC.
This patch merges createGdbIndex function and GdbIndexSection's
constructor into a single static member function of the class.

This patch also change how we keep CU vectors. Previously, CuVector
and GdbSymbols were parallel arrays, but there's no reason to choose that
design. Now, CuVector is a member of GdbSymbol class.

A lot of members are removed from GdbIndexSection. Previously, it has
members that need to be kept in sync over several phases. I belive the new
design is less error-prone, and the new code is much easier to read
than before.

llvm-svn: 336743
2018-07-10 23:48:27 +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