There are 3 symbol types that a .bc can provide during lto: defined,
undefined, common.
Defined and undefined symbols have already been refactored. I was
working on common and noticed that absolute symbols would become an
oddity: They would be the only symbol type present in a .o but not in
a.bc.
Looking a bit more, other than the special section number they were only
used for special rules for computing values. In that way they are
similar to TLS, and we don't have a DefinedTLS.
This patch deletes it. With it we have a reasonable rule of the thumb
for having a symbol kind: It exists if it has special resolution
semantics.
llvm-svn: 256383
In FreeBSD, rtld expects .ctors containing -1 (0xffffffff), and a
.ctors section containing the correct bits is provided to the linker as
input (/usr/lib/crtbegin.o).
Contents of section .ctors:
0000 ffffffff ffffffff ........
This section is not stripped even if not referenced or empty, also in
gold or ld.bfd. It would be nice to strip it when not needed but
since existing object files rely on that we can't do better to keep it
around.
Differential Revision: http://reviews.llvm.org/D15767
llvm-svn: 256373
Before this patch sections that go after relro sequence were placed at
the same memory page with relro ones. It caused segmentation fault on
freebsd.
Fixes PR25790.
Patch by George Rimar with some tweaks by myself.
llvm-svn: 256334
I am working on adding LTO support to the new ELF lld.
In order to do that, it will be necessary to represent defined and
undefined symbols that are not from ELF files. One way to do it is to
change the symbol hierarchy to look like
Defined : SymbolBody
Undefined : SymbolBody
DefinedElf<ELFT> : Defined
UndefinedElf<ELFT> : Undefined
Another option would be to use bogus Elf_Sym, but I think that is
getting a bit too hackish.
This patch does the Undefined/UndefinedElf. Split. The next one
will do the Defined/DefinedElf split.
llvm-svn: 256289
The patch adds support for R_MIPS_PC16, R_MIPS_PC19_S2, R_MIPS_PC21_S2,
R_MIPS_PC26_S2, R_MIPS_PCHI16, R_MIPS_PCLO16 relocations handling.
llvm-svn: 256172
This patch changes sequence of applying relocations, moving tls optimized relocation handling code before code for other locals.
Without that change relocation @GOTTPOFF against local symbol caused runtime error ("unrecognized reloc ...").
That change also should fix other tls optimized relocations, but I did not check them, that's a field for another patch.
R_X86_64_GOTTPOFF relocations against locals can be found when linking against libc.a(malloc.o):
000000000036 000600000016 R_X86_64_GOTTPOFF 0000000000000000 libc_tsd_MALLOC - 4
000000000131 000600000016 R_X86_64_GOTTPOFF 0000000000000000 libc_tsd_MALLOC - 4
Differential revision: http://reviews.llvm.org/D15581
llvm-svn: 256145
This relocation is similar to R_*_RELATIVE except that the value used in this relocation is the program address returned by the function, which takes no arguments, at the address of
the result of the corresponding R_*_RELATIVE relocation as specified in the processor-specific ABI. The purpose of this relocation to avoid name lookup for locally defined STT_GNU_IFUNC symbols at load-time.
More info can be found in ifunc.txt from https://sites.google.com/site/x32abi/documents.
Differential revision: http://reviews.llvm.org/D15235
llvm-svn: 256144
R_386_GOTOFF is calculated as S + A - GOT, where:
S - Represents the value of the symbol whose index resides in the relocation entry.
A - Represents the addend used to compute the value of the relocatable field.
GOT - Represents the address of the global offset table.
Differential revision: http://reviews.llvm.org/D15383
llvm-svn: 256143
MIPS .reginfo section provides information on the registers used by
the code in the object file. Linker should collect this information and
write .reginfo section in the output file. This section contains a union
of used registers masks taken from input .reginfo sections and final
value of the `_gp` symbol.
For details see the "Register Information" section in Chapter 4 in the
following document:
ftp://www.linux-mips.org/pub/linux/mips/doc/ABI/mipsabi.pdf
The patch implements .reginfo sections handling with a couple missed
features: a) it does not put output .reginfo section into the separate
REGINFO segment; b) it does not merge `ri_cprmask` masks from input
section. These features will be implemented later.
Differential Revision: http://reviews.llvm.org/D15669
llvm-svn: 256119
The patch configure ELF header flags for MIPS target. For now the flags
are hard coded. In fact they depends on ELF flags of input object files
and selected emulation.
Differential Revision: http://reviews.llvm.org/D15575
llvm-svn: 256089
The assembly at the top of this file contained more relocations than
the YAML. I regenerated it so that we'd have complete relocation testing.
Also added detailed explanations of the relocations in the file so that
future people don't have to try decode them when something goes wrong.
llvm-svn: 256064
@indntpoff is similar to @gotntpoff, but for use in position dependent code. While @gotntpoff resolves to GOT slot address relative to the
start of the GOT in the movl or addl instructions, @indntpoff resolves to the
absolute GOT slot address. ("ELF Handling For Thread-Local Storage", Ulrich Drepper).
Differential revision: http://reviews.llvm.org/D15494
llvm-svn: 255884
Previously, OffsetInBSS is -1 if it has no information about copy
relocation, 0 if it needs a copy relocation, and >0 if its offset
in BSS has been assigned. These flags were too subtle. This patch
adds a new flag, NeedsCopy, to carry information about whether
a shared symbol needs a copy relocation or not.
llvm-svn: 255865
The function was used only in Writer.cpp and did not depend on SymbolTable.
There is no reason to have that function in SymbolTable.cpp.
llvm-svn: 255850
addELFFile was called only from addFile, and what it did was actually
just adding a file to the symbol table. There seems to be no reason
to separate the two.
llvm-svn: 255839
negDelta32 is only ever implicitly generated as the FDE->CIE reference.
We therefore don't emit a relocation for it in the object file in -r mode.
The value we write in to the FDE location therefore needs to point to the
final target address of the CIE, and not the inAtomAddress as it was currently
doing.
llvm-svn: 255835
After r255819, parse() actually parses what you pass it.
This test was failing because it passed '--debug-only' which isn't in
release builds, but also 'foo' which isn't an option at all.
We now pass -enable-tbaa and -enable-misched which are real options.
llvm-svn: 255822
We used to parse the LLVM options in Driver::link. However, that is
after parse() where we load files. By moving the LLVM option handling
earlier, we can add DEBUG() to code such as MachONormalizedFileToAtoms.cpp
and have it enabled correctly by '-mllvm --debug'.
llvm-svn: 255819
We had some DEBUG prints these passes, but add more so that its clear where we are dumping
things, and what state we are in when we do so.
I'll be adding more and more DEBUG printing to try make it easier to observe whats going on
without having to attach a debugger.
llvm-svn: 255805
The `_gp_disp` is a magic symbol designates offset between start of
function and gp pointer into GOT. Only `R_MIPS_HI16` and `R_MIPS_LO16`
relocations are permitted with `_gp_disp`. The patch adds the `_gp_disp`
as an ignored symbol and adjusts symbol value before call the `relocateOne`
for `R_MIPS_HI16/LO16` relocations.
Differential Revision: http://reviews.llvm.org/D15480
llvm-svn: 255768
[ELF] - refactor of code in RelocationSection<ELFT>::writeTo()
Just a little reformat of 'if' conditions, NFC.
Differential revision: http://reviews.llvm.org/D15453
Fix was:
* Renamed unsigned Rel; to unsigned Reloc;
llvm-svn: 255631
as it broke buildbot:
http://lab.llvm.org:8011/builders/lld-x86_64-darwin13/builds/17836/steps/build_Lld/logs/stdio
/Users/buildslave/as-bldslv9/lld-x86_64-darwin13/llvm.src/tools/lld/ELF/OutputSections.cpp:268:14: error: redefinition of 'Rel'
unsigned Rel; ^
/Users/buildslave/as-bldslv9/lld-x86_64-darwin13/llvm.src/tools/lld/ELF/OutputSections.cpp:241:34: note: previous definition is here
for (const DynamicReloc<ELFT> &Rel : Relocs) {
That compiles fine on my MSVS 2015 thought.
llvm-svn: 255628
The `R_MIPS_JALR` is a relocation generated by gcc and gas. This
relocation points to the `jalr` instruction which might be optimized and
converted to the `b` instruction under some conditions.
Now we just ignore this relocation and keep instructions unchanged.
llvm-svn: 255453
If we don't filter these out we can end up, generating bogus paths, for example:
/home/user/lld/build/bin -> /home/user/home/user/lld/build/bin/lld/build/bin.
llvm-svn: 255378
It is reasonable to specify an entry point for shared objects - for
example, for the FreeBSD rtld ld-elf.so.1.
Unlike GNU ld we leave the entry address as 0 if -shared is specified
without -e.
Differential Revision: http://reviews.llvm.org/D15454
llvm-svn: 255349
R_X86_64_SIZE64/R_X86_64_SIZE32 relocations were introduced in 0.98v of "System V Application Binary Interface x86-64" (http://www.x86-64.org/documentation/abi.pdf).
Calculation for them is Z + A, where:
Z - Represents the size of the symbol whose index resides in the relocation entry.
A - Represents the addend used to compute the value of the relocatable field.
Differential revision: http://reviews.llvm.org/D15335
llvm-svn: 255332
When llvm-lit prints a failure, you'll see something like 'lld *command*' However, you can't then take this, paste it in to a terminal and run it, because it's not got the absolute path of lld.
llvm and clang's lit.cfg files contain lists of commands to look for which are substituted by their full paths. So now you'd see something like '*build dir*/bin/lld *command*'.
This patch adds the same capability to lld's lit.cfg
Reviewed by Rafael Espíndola
llvm-svn: 255283
The delta64 relocation is represented as the pair ARM64_RELOC_SUBTRACTOR and ARM64_RELOC_UNSIGNED.
Those should always have the same offset, so this adds a check and tests to ensure this is the case.
Also updated the error printing in this case to shows both relocs when erroring on pair.
llvm-svn: 255274
List all sections removed by garbage collection. This option is only effective if garbage collection has been enabled via the `--gc-sections' option.
Differential revision: http://reviews.llvm.org/D15327
llvm-svn: 255235
If R_386_PLT32 relocation is applied against symbol that can not be preempted then it can be resolved statically.
Patch implements it for x86 target.
Differential revision: http://reviews.llvm.org/D15376
llvm-svn: 255233
table.
The first entry in the MachO symbol table is always the empty string: make sure
we reserve space for it, or we will overflow the symbol table by one byte.
No test case - this manifests as an occasional memory error. In the near future
I hope to set up a bot building and runnnig LLD with sanitizers - that should
catch future instances of this issue.
llvm-svn: 255178
Implement the TLS relocation optimization for 32-bit x86 that is described in
"ELF Handling For Thread-Local Storage" by Ulrich Drepper, chapter 5,
"IA-32 Linker Optimizations". Specifically, this patch implements these
optimizations: LD->LE, GD->IE, GD->LD, and IE->LE.
Differential revision: http://reviews.llvm.org/D15292
llvm-svn: 255103
The gcc_except_tab was generating these references to point to the typeinfo in the data section.
gcc_except_tab also had the DW_EH_PE_indirect flag set which means that at runtime we are going
to dereference this entry as if it is in the GOT.
Reviewed by Nick Kledzik in http://reviews.llvm.org/D15360.
llvm-svn: 255085
MSVC linker considers PDB files created with this patch valid.
So you don't have to remove PDB files created by lld before
running MSVC linker.
This patch has no test since llvm-pdbdump dislikes PDB files
with no metadata streams.
llvm-svn: 255039
All relocations, which cannot be handled by the dynamic linker,
cause a linking error "rebuild with -fPIC".
Differential revision: http://reviews.llvm.org/D15193
llvm-svn: 254840
Before this patch, we created an empty PDB file if /debug option is
specified. For MSVC linker, such PDB file is completely broken, and
linker exits without doing anything as soon as it finds an empty PDB
file.
A PDB file created in this patch has the correct file signature.
MSVC linker still thinks that the file is broken, but it then removes
and replaces with its output.
This is an initial patch to support PDB in LLD. We aim to support
PDB in order to make it 100% compatible with MSVC linker. PDB support
is the last missing piece.
llvm-svn: 254796
"Ulrich Drepper, ELF Handling For Thread-Local Storage" (5.5 x86-x64 linker optimizations, http://www.akkadia.org/drepper/tls.pdf) shows how GD can be optimized to IE.
This patch implements the optimization.
Differential revision: http://reviews.llvm.org/D15000
llvm-svn: 254713
Rafael Espindola