This generalizes the old heuristic placing SHT_DYNSYM SHT_DYNSTR first in the readonly SHF_ALLOC segment.
Reviewers: espindola
Subscribers: emaste, arichardson, llvm-commits
Differential Revision: https://reviews.llvm.org/D48406
llvm-svn: 335674
This CL places .dynsym and .dynstr at the beginning of SHF_ALLOC
sections. We do this to mitigate the possibility that huge .dynsym and
.dynstr sections placed between ro-data and text sections cause
relocation overflow.
Differential Revision: https://reviews.llvm.org/D45788
llvm-svn: 332374
This CL is to mitigate R_X86_64_PC32 relocation overflow problems for huge binaries that has near 4G allocated sections.
By examining those binaries, there're 2 issues contributes to the problem:
1). huge ".dynsym" and ".dynstr" stands in the way between .rodata and .text
2). _init_array_start/end are placed at 0 if no ".init_array" presents, this causes .text relocation against them become more prone to overflow.
This CL addresses 1st problem (the 2nd will be addressed in another CL.) by assigning a smaller sortrank to .dynsym and .dynstr thus they no longer stand in between.
llvm-svn: 332038
Newer versions of the gnu assembler produce a X86_64_PLT32 for
calls. There is a change under review in llvm to do the same, so update
the tests to not depend on it.
We can still produce a R_X86_64_PC32 with ".long foo - .".
llvm-svn: 325379
Its PR34712,
GNU linkers recently changed default values to "both" of "sysv".
Patch do the same for all targets except MIPS, where .gnu.hash
section is not yet supported.
Code suggested by Rui Ueyama.
Differential revision: https://reviews.llvm.org/D38407
llvm-svn: 315051
Align to the large page size (known as a superpage or huge page).
FreeBSD automatically promotes large, superpage-aligned allocations.
Differential Revision: https://reviews.llvm.org/D27042
llvm-svn: 287782
Versions can be assigned to symbols in two different ways.
One is the usual version scripts, and the other is special
symbol suffix '@'. If a symbol contains '@', the string after
that is considered to specify a version name.
Previously, we look for '@' for all symbols.
Anything that works on every symbol can be expensive because
the linker has to handle a lot of symbols. The search for '@'
was not an exception.
In this patch, I made two optimizations.
The first optimization is to handle '@' only when at least one
version is defined. If no versions are defined, no versions can
be assigned to any symbols, so it's waste of time to search for '@'.
The second optimization is to scan only suffixes of symbol names
instead of entire symbol names. Symbol names can be very long, but
symbol versions are usually short, so scanning entire symbol names
is waste of time, too.
There are some error cases which we no longer be able to detect
with this patch. I don't think it's a major drawback because they
are minor errors. Speed is more important.
This change improves LLD with debug info self-link time from
6.6993 seconds to 6.3426 seconds (or -5.3%).
Differential Revision: https://reviews.llvm.org/D22433
llvm-svn: 275711
This is PR28358
According to
https://www.akkadia.org/drepper/dsohowto.pdf
"The fourth point, the VERS 1.0 version being referred to in the VERS 2.0 definition, is not really important in symbol versioning. It marks the predecessor relationship of the two versions and it is done to maintain the similar- ities with Solaris’ internal versioning. It does not cause any problem it might in fact be useful to a human reader so predecessors should always be mentioned."
Patch partially reverts 273423 "[ELF] - Implemented version script hierarchies.",
version references are just ignored now.
Differential revision: http://reviews.llvm.org/D21888
llvm-svn: 274345
t is possible to create new version of symbol instead of depricated one
using combination of version script and asm commands. For example:
__asm__(".symver b_1,b@LIBSAMPLE_1.0");
int b_1() { return 10; }
__asm__(".symver b_2,b@@LIBSAMPLE_2.0");
int b_2() { return 20; }
This code makes b_2() to be default implementation for b().
b_1() is used for compatibility with binaries compiled against
library of older version LIBSAMPLE_1.0.
This patch implements support for above functionality in lld.
Differential revision: http://reviews.llvm.org/D21681
llvm-svn: 274002
Fangrui Song