This patch adds some TLS relocations and relaxations for AArch64.
Some Global-Dynamic relocation are handled by optimizing them to
Local-Exec (Initial-Exec is not yet supported). They are:
- R_AARCH64_TLSDESC_ADR_PAGE21
- R_AARCH64_TLSDESC_LD64_LO12_NC
- R_AARCH64_TLSDESC_ADD_LO12_NC
- R_AARCH64_TLSDESC_CALL
Also some Init-Exec is optimized to Local-Exec if possible. They are:
- R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21
- R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC
Finally some Local-Exec relocation are handled in relocateOne:
- R_AARCH64_TLSLE_ADD_TPREL_HI12
- R_AARCH64_TLSLE_ADD_TPREL_LO12_NC
This work is mainly for compiler bootstrap, where static binaries is
showing good progress (although shared object still lacking support
from both TLS aarch64 backend and some other issues).
llvm-svn: 260677
Previously, Target held a value until a new value is assigned to the
variable. That was a benign leak -- that was not an unbounded leak
and didn't grab any resources except a small amount of memory. But
it is better to fix than leaving as is.
llvm-svn: 260592
R_X86_64_TPOFF64 is a dynamic relocation,
it should not appear in static relocation processing.
Patch fixes it.
Differential revision: http://reviews.llvm.org/D16880
llvm-svn: 260508
The patch adds lazy relocation support for MIPS and R_MIPS_26 relocation
handing.
R_MIPS_26 relocation might require PLT entry creation. In that case it
is fully supported by the patch. But if the relocation target is a local
symbol we need to use a different expression to calculate the relocation
result. This case is not implemented yet because there is no method to
get know the kind of relocation target in the `relocateOne` routine.
Differential Revision: http://reviews.llvm.org/D16982
llvm-svn: 260424
MIPS 32-bit ABI uses REL relocation record format. We read addends from
relocation destinations right in the MipsTargetInfo::relocateOne
function.
llvm-svn: 260364
This is the function equivalent of a copy relocation.
Since functions are expected to change sizes, we cannot use copy
relocations. In situations where one would be needed, what is done
instead is:
* Create a plt entry
* Output an undefined symbol whose addr is the plt entry.
The dynamic linker makes sure any shared library uses the plt entry as
the function address.
llvm-svn: 260224
Symbol does not need an entry i the 'global' part of GOT if it cannot be
preempted. So canBePreempted fully satisfies us at least for now.
llvm-svn: 259779
This function is a predicate that a given relocation can be relaxed.
The previous name implied that it returns true if a given relocation
has already been optimized away.
llvm-svn: 259128
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
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
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
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
Fix: Added missed input file.
Initial commit message:
[ELF/AArch64] - Implemented R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21 and R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC relocations
* R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21 is calculated as Page(G(GTPREL(S+A))) – Page(P), set an ADRP immediate field to bits [32:12] of X; check –2^32 ≤ X < 2^32;
* R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC is calculated as G(GTPREL(S+A)), set an LD offset field to bits [11:3] of X. No overflow check; check that X&7 = 0.
Differential revision: http://reviews.llvm.org/D16117
llvm-svn: 257596
* R_AARCH64_TLSIE_ADR_GOTTPREL_PAGE21 is calculated as Page(G(GTPREL(S+A))) – Page(P), set an ADRP immediate field to bits [32:12] of X; check –2^32 ≤ X < 2^32;
* R_AARCH64_TLSIE_LD64_GOTTPREL_LO12_NC is calculated as G(GTPREL(S+A)), set an LD offset field to bits [11:3] of X. No overflow check; check that X&7 = 0.
Differential revision: http://reviews.llvm.org/D16117
llvm-svn: 257588
R_AARCH64_TSTBR14 is calculated as S+A-P,
Set the immediate field of a TBZ/TBNZ instruction to bits [15:2] of X; check -2^15 ≤ X < 2^15
Differential revision: http://reviews.llvm.org/D15824
llvm-svn: 257334
R_AARCH64_CONDBR19 is calculated as S+A-P,
Set the immediate field of a conditional branch instruction to bits [20:2] of X; check -2^20 ≤ X< 2^20.
Afaik there is no document for AARCH64 instruction encoding from official for unknown reason, so
I used gold source code and next link as a reference for implementation: http://kitoslab-eng.blogspot.ru/2012/10/armv8-aarch64-instruction-encoding.html. From which is clear that immediate field of a conditional branch instruction is 5 bits off. That is proved by output which is is equal to gold/bfd now.
Differential revision: http://reviews.llvm.org/D15809
llvm-svn: 257333
R_X86_64_PLT32 is handled in the same way as R_X86_64_PC32 by
relocateOne(), so this function does not seems to be needed.
Without this code, all tests still pass.
http://reviews.llvm.org/D15971
llvm-svn: 257203
All non-trivial relocation decisions need explanations like this
to help readers understand not only how relocations are handled but
why they are handled these ways. This is a start.
llvm-svn: 257119
Summary: This will allow us to remove the AMDGPU support from old ELF.
Reviewers: rafael, ruiu
Differential Revision: http://reviews.llvm.org/D15895
llvm-svn: 257023
The R_MIPS_GPREL16 / R_MIPS_GPREL32 relocations use the following
expressions for calculations:
```
local symbol: S + A + GP0 - GP
global symbol: S + A - GP
GP - Represents the final gp value, i.e. _gp symbol
GP0 - Represents the gp value used to create the relocatable object
```
The GP0 value is taken from the .reginfo data section defined by an object
file. To implement that I keep a reference to `MipsReginfoInputSection`
in the `ObjectFile` class. This reference is used by the
`ObjectFile::getMipsGp0` method to return the GP0 value.
Differential Revision: http://reviews.llvm.org/D15760
llvm-svn: 256416
