In many situations, we don't want to exit at the first error even in the
process model. For example, it is better to report all undefined symbols
rather than reporting the first one that the linker picked up randomly.
In order to handle such errors, we don't need to wrap everything with
ErrorOr (thanks for David Blaikie for pointing this out!) Instead, we
can set a flag to record the fact that we found an error and keep it
going until it reaches a reasonable checkpoint.
This idea should be applicable to other places. For example, we can
ignore broken relocations and check for errors after visiting all relocs.
In this patch, I rename error to fatal, and introduce another version of
error which doesn't call exit. That function instead sets HasError to true.
Once HasError becomes true, it stays true, so that we know that there
was an error if it is true.
I think introducing a non-noreturn error reporting function is by itself
a good idea, and it looks to me that this also provides a gradual path
towards lld-as-a-library (or at least embed-lld-to-your-program) without
sacrificing code readability with lots of ErrorOr's.
http://reviews.llvm.org/D16641
llvm-svn: 259069
This does not solve the problem that we call isGnuIFunc function
both from RelocationSection and from the Writer::scanRelocs, but
this at least should improve readability. I'm taking an incremental
approach to reduce complexity.
llvm-svn: 258753
There are a few cases where we have almost duplicated code.
This patches fixes the simplest: the finalize and write of dynamic
section. Right now they have to have exactly the same structure to
decide if a DT_* entry is needed and then to actually write it.
We cannot just write it to a std::vector in the first pass since
addresses have not been computed yet.
llvm-svn: 258723
Main executable did not export symbols that exist both in the main executable and in DSOs before this patch.
Symbols from object files that override symbols in DSO should be added to .dynsym table.
Differential revision: http://reviews.llvm.org/D16405
llvm-svn: 258672
Summary: It looks like this snuck through in r256143/D15383.
Reviewers: ruiu, grimar
Differential Revision: http://reviews.llvm.org/D16500
llvm-svn: 258599
There was an off by one error because the StringRef.substr functions
second argument is a length, not the end index.
Also updated a few ELF files which failed when run on Jenkins with paths
including the @ character. This is often used in Jenkins for shared
workspace plugin.
Reviewed by Rui Ueyama
llvm-svn: 258583
In InputSection.cpp it was possible to dereference null.
Had to change signature of relocateTlsOptimize to accept pointer instead of reference.
Differential revision: http://reviews.llvm.org/D16466
llvm-svn: 258508
In this code, we avoid calling needsCopyRel in writeTo because
we called that function already in scanRelocs. Making the same
decision twice is a waste and has a risk of a bug that we get
inconsistent resuts.
llvm-svn: 258430
Code for handling TLS relocations was moved out scanRelocs() to new function handleTlsRelocations().
That is because scanRelocs already too large to put more TLS code into it.
Differential revision: http://reviews.llvm.org/D16354
llvm-svn: 258392
Some MIPS relocation (for now R_MIPS_GOT16) requires creation of GOT
entries for symbol not included in the dynamic symbol table. They are
local symbols and non-local symbols with 'local' visibility. Local GOT
entries occupy continuous block between GOT header and regular GOT
entries.
The patch adds initial support for handling local GOT entries. The main
problem is allocating local GOT entries for local symbols. Such entries
should be initialized by high 16-bit of the symbol value. In ideal world
there should be no duplicated entries with the same values. But at the
moment of the `Writer::scanRelocs` call we do not know a value of the
symbol. In this patch we create new local GOT entry for each relocation
against local symbol, though we can exhaust GOT quickly. That needs to
be optimized later. When we calculate relocation we know a final symbol
value and request local GOT entry index. To do that we maintain map
between addresses and local GOT entry indexes. If we start to calculate
relocations in parallel we will have to serialize access to this map.
Differential Revision: http://reviews.llvm.org/D16324
llvm-svn: 258388
Added check for terminator CIE/FDE which has zero data size.
void EHOutputSection<ELFT>::addSectionAux(
...
// If CIE/FDE data length is zero then Length is 4, this
// shall be considered a terminator and processing shall end.
if (Length == 4)
break;
...
After this "Bug 25923 - lld/ELF2 linked application crashes if exceptions were used." is fixed for me. Self link of clang also works.
Initial commit message:
[ELF] - implemented --eh-frame-hdr command line option.
--eh-frame-hdr
Request creation of ".eh_frame_hdr" section and ELF "PT_GNU_EH_FRAME" segment header.
Both gold and the GNU linker support an option --eh-frame-hdr which tell them to construct a header for all the .eh_frame sections. This header is placed in a section named .eh_frame_hdr and also in a PT_GNU_EH_FRAME segment. At runtime the unwinder can find all the PT_GNU_EH_FRAME segments by calling dl_iterate_phdr.
This section contains a lookup table for quick binary search of FDEs.
Detailed info can be found here:
http://www.airs.com/blog/archives/462
Differential revision: http://reviews.llvm.org/D15712
llvm-svn: 257889
MIPS ABI has relocations like R_MIPS_JALR which is just a hint for
linker to make some code optimization. Such relocations should not be
handled as a regular ones and lead to say dynamic relocation creation.
The patch introduces new virtual `Target::isHintReloc` method, overrides
it in the `MipsTargetInfo` class and calls it in the `Writer<ELFT>::scanRelocs`
method.
Differential Revision: http://reviews.llvm.org/D16193
llvm-svn: 257798
--eh-frame-hdr
Request creation of ".eh_frame_hdr" section and ELF "PT_GNU_EH_FRAME" segment header.
Both gold and the GNU linker support an option --eh-frame-hdr which tell them to construct a header for all the .eh_frame sections. This header is placed in a section named .eh_frame_hdr and also in a PT_GNU_EH_FRAME segment. At runtime the unwinder can find all the PT_GNU_EH_FRAME segments by calling dl_iterate_phdr.
This section contains a lookup table for quick binary search of FDEs.
Detailed info can be found here:
http://www.airs.com/blog/archives/462
Differential revision: http://reviews.llvm.org/D15712
llvm-svn: 257753
It seems that __cxa_demangle function on the buildbot tried to demangle
a variable "tlsvar" as a C++ symbol. Do not call that function unless
it does not start with "_Z" which is the prefix of mangled names.
llvm-svn: 257661
Rui Ueyama