Commit Graph

17 Commits

Author SHA1 Message Date
Fangrui Song 249fde8583 [ELF][ARM][AARCH64][MIPS][PPC] Simplify the logic to create R_*_RELATIVE for absolute relocation types in writable sections
Summary:
Our rule to create R_*_RELATIVE for absolute relocation types were
loose. D63121 made it stricter but it failed to create R_*_RELATIVE for
R_ARM_TARGET1 and R_PPC64_TOC. rLLD363236 worked around that by
reinstating the original behavior for ARM and PPC64.

This patch is an attempt to simplify the logic.

Note, in ld.bfd, R_ARM_TARGET2 --target2=abs also creates
R_ARM_RELATIVE. This seems a very uncommon scenario (moreover,
--target2=got-rel is the default), so I do not implement any logic
related to it.

Also, delete R_AARCH64_ABS32 from AArch64::getDynRel. We don't have
working ILP32 support yet. Allowing it would create an incorrect
R_AARCH64_RELATIVE.

For MIPS, the (if SymbolRel, then RelativeRel) code is to keep its
behavior unchanged.

Note, in ppc64-abs64-dyn.s, R_PPC64_TOC gets an incorrect addend because
computeAddend() doesn't compute the correct address. We seem to have the
wrong behavior for a long time. The important thing seems that a dynamic
relocation R_PPC64_TOC should not be created as the dynamic loader will
error R_PPC64_TOC is not supported.

Reviewers: atanasyan, grimar, peter.smith, ruiu, sfertile, espindola

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D63383

llvm-svn: 363928
2019-06-20 14:00:08 +00:00
Fangrui Song 025a815d75 [ELF] Make the rule to create relative relocations in a writable section stricter
The current rule is loose: `!Sym.IsPreemptible || Expr == R_GOT`.

When the symbol is non-preemptable, this allows absolute relocation
types with smaller numbers of bits, e.g. R_X86_64_{8,16,32}. They are
disallowed by ld.bfd and gold, e.g.

    ld.bfd: a.o: relocation R_X86_64_8 against `.text' can not be used when making a shared object; recompile with -fPIC

This patch:

a) Add TargetInfo::SymbolicRel to represent relocation types that resolve to a
symbol value (e.g. R_AARCH_ABS64, R_386_32, R_X86_64_64).

  As a side benefit, we currently (ab)use GotRel (R_*_GLOB_DAT) to resolve
  GOT slots that are link-time constants. Since we now use Target->SymbolRel
  to do the job, we can remove R_*_GLOB_DAT from relocateOne() for all targets.
  R_*_GLOB_DAT cannot be used as static relocation types.
b) Change the condition to `!Sym.IsPreemptible && Type != Target->SymbolicRel || Expr == R_GOT`.

Some tests are caught by the improved error checking (ld.bfd/gold also
issue errors on them). Many misuse .long where .quad should be used
instead.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D63121

llvm-svn: 363059
2019-06-11 12:59:30 +00:00
Fangrui Song e98baf8631 [ELF] Delete GotEntrySize and GotPltEntrySize
GotEntrySize and GotPltEntrySize were added in D22288. Later, with
the introduction of wordsize() (then Config->Wordsize), they become
redundant, because there is no target that sets GotEntrySize or
GotPltEntrySize to a number different from Config->Wordsize.

Reviewed By: grimar, ruiu

Differential Revision: https://reviews.llvm.org/D62727

llvm-svn: 362220
2019-05-31 10:35:45 +00:00
Rui Ueyama b8b81e9b43 Improve error message for unknown relocations.
Previously, we showed the following message for an unknown relocation:

  foo.o: unrecognized reloc 256

This patch improves it so that the error message includes a symbol name:

  foo.o: unknown relocation (256) against symbol bar

llvm-svn: 354040
2019-02-14 18:02:20 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
George Rimar 95aae4c59d [ELF] - Do not fail on R_*_NONE relocations when parsing the debug info.
This is https://bugs.llvm.org//show_bug.cgi?id=38919.

Currently, LLD may report "unsupported relocation target while parsing debug info"
when parsing the debug information.

At the same time LLD does that for zeroed R_X86_64_NONE relocations,
which obviously has "invalid" targets.

The nature of R_*_NONE relocation assumes them should be ignored.
This patch teaches LLD to stop reporting the debug information parsing errors for them.

Differential revision: https://reviews.llvm.org/D52408

llvm-svn: 343078
2018-09-26 08:11:34 +00:00
Konstantin Zhuravlyov d70c367267 AMDGPU/LLD: Handle R_AMDGPU_REL64 relocation
Requires r334443 from llvm

Differential Revision: https://reviews.llvm.org/D47734

llvm-svn: 334444
2018-06-11 21:42:53 +00:00
Rui Ueyama f52496e1e0 Rename SymbolBody -> Symbol
Now that we have only SymbolBody as the symbol class. So, "SymbolBody"
is a bit strange name now. This is a mechanical change generated by

  perl -i -pe s/SymbolBody/Symbol/g $(git grep -l SymbolBody lld/ELF lld/COFF)

nd clang-format-diff.

Differential Revision: https://reviews.llvm.org/D39459

llvm-svn: 317370
2017-11-03 21:21:47 +00:00
Bob Haarman b8a59c8aa5 [lld] unified COFF and ELF error handling on new Common/ErrorHandler
Summary:
The COFF linker and the ELF linker have long had similar but separate
Error.h and Error.cpp files to implement error handling. This change
introduces new error handling code in Common/ErrorHandler.h, changes the
COFF and ELF linkers to use it, and removes the old, separate
implementations.

Reviewers: ruiu

Reviewed By: ruiu

Subscribers: smeenai, jyknight, emaste, sdardis, nemanjai, nhaehnle, mgorny, javed.absar, kbarton, fedor.sergeev, llvm-commits

Differential Revision: https://reviews.llvm.org/D39259

llvm-svn: 316624
2017-10-25 22:28:38 +00:00
Rui Ueyama 51f604ce66 Simplify.
llvm-svn: 316486
2017-10-24 19:40:03 +00:00
Konstantin Zhuravlyov b71d1b8a54 LLD/ELF/AMDGPU: Process AMDGPU-specific e_flags
Differential Revision: https://reviews.llvm.org/D39140

llvm-svn: 316483
2017-10-24 19:05:32 +00:00
Tony Tye 394e1dde6e Add base relative relocation record that can be used for the following case (OpenCL example):
static __global int Var = 0; 
__global int* Ptr[] = {&Var};
...

In this case Var is a non premptable symbol and so its address can be used as the value of Ptr, with a base relative relocation that will add the delta between the ELF address and the actual load address. Such relocations do not require a symbol.

This also fixes LLD which was incorrectly generating a PCREL64 for this case.

Differential Revision: https://reviews.llvm.org/D38910

llvm-svn: 315936
2017-10-16 20:46:53 +00:00
Rui Ueyama be85529d2b Remove one parameter from Target::getRelExpr.
A section was passed to getRelExpr just to create an error message.
But if there's an invalid relocation, we would eventually report it
in relocateOne. So we don't have to pass a section to getRelExpr.

llvm-svn: 315552
2017-10-12 03:14:06 +00:00
Rui Ueyama 67533a2cb3 Define RelType to represent relocation types.
We were using uint32_t as the type of relocation kind. It has a
readability issue because what Type really means in `uint32_t Type`
is not obvious. It could be a section type, a symbol type or a
relocation type.

Since we do not do any arithemetic operations on relocation types
(e.g. adding one to R_X86_64_PC32 doesn't make sense), it would be
more natural if they are represented as enums. Unfortunately, that
is not doable because relocation type definitions are spread into
multiple header files.

So I decided to use typedef. This still should be better than the
plain uint32_t because the intended type is now obvious.

llvm-svn: 315525
2017-10-11 22:49:24 +00:00
Rafael Espindola 3bab91332f Fix which file is in an error message.
When reporting an invalid relocation we were blaming the destination
file instead of the file with the relocation.

llvm-svn: 310084
2017-08-04 18:33:16 +00:00
Rui Ueyama e145bc22fd Do not use make<> to allocate TargetInfo. NFC.
llvm-svn: 305577
2017-06-16 20:15:03 +00:00
Rui Ueyama 21c0a9ceeb Split Target.cpp into small files.
Target.cpp contains code for all the targets that LLD supports. It was
simple and easy, but as the number of supported targets increased,
it got messy.

This patch splits the file into per-target files under ELF/arch directory.

Differential Revision: https://reviews.llvm.org/D34222

llvm-svn: 305565
2017-06-16 17:32:43 +00:00