Each rule in SECTIONS commands is something like ".foo *(.baz.*)",
which instructs the linker to collect all sections whose name matches
".baz.*" from all files and put them into .foo section.
Previously, we didn't recognize the wildcard character. This patch
adds that feature.
Performance impact is a bit concerning because a linker script can
contain hundreds of SECTIONS rules, and doing pattern matching against
each rule would be too expensive. We could merge all patterns into
single DFA so that it takes O(n) to the input size. However, it is
probably too much at this moment -- we don't know whether the
performance of pattern matching matters or not. So I chose to
implement the simplest algorithm in this patch. I hope this simple
pattern matcher is sufficient.
llvm-svn: 260745
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, if both A and B are ".ctors", both compCtors(A, B) and
compCtors(B, A) are true, which is a violation of the strict weak
ordering because such function is not antisymmetric.
llvm-svn: 260633
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
Previously, we had code for linker scripts in Writer. This patch
separates that as LinkerScript class. The class provides a few
functions to query linker scripts and is also a container of some
linker-script-specific information.
Hopefully, Writer will only implement the default behavior and let
the new class handle gotchas regarding linker scripts.
llvm-svn: 260591
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
They don't count for the memory or file size, so this is mostly just a
simplification.
The only noticeable difference should be fewer empty program headers.
llvm-svn: 260465
Global constructors and destructors are guaranteed to be called
in the order as they appear in a translation unit. So we don't want
to mess up the order if they have the same priority.
llvm-svn: 260463
IMHO this makes the code easier to read and should help with linker
scripts.
This is strongly based on D16575. The main differences are:
We record a range of sections, not every section in a program header.
scanHeaders takes case of deciding what goes in every program header,
including PT_GNU_RELRO
We create dummy sections for the start of the file
With this, program header creation has 3 isolated stages:
Map sections to program headers.
Assign addresses to *sections*
Looking at sections find the address and size of each program header.
Thanks to George Rimar for the initial version.
llvm-svn: 260453
We have a vector of all of the compact unwind entries anyway, and
its live as long as we need it to be. So instead of copying from that
vector to another, just take references to the range of the original vector
we need for each compact unwind page.
llvm-svn: 260437
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 basically reverts commit r260073 because it is found that
augmentation strings don't always start with "zR". It is reported
as https://llvm.org/bugs/show_bug.cgi?id=26541.
llvm-svn: 260294
The non lazy atoms generated in the stubs pass use an image cache to
hold all of the pointers. On arm archs, this is the __got section,
but on x86 archs it should be __nl_symbol_ptr.
rdar://problem/24572729
llvm-svn: 260271
ld64 aligns most of the stub's to 2 byte alignment, expect for
the stub helper common atoms which are 4 byte aligned.
This adds a new field to StubInfo which tracks this alignment
and ensures that this is the alignment we get in the final image.
rdar://problem/24570220
llvm-svn: 260248
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
Also added the defaults for whether to generate this load command, which
the cmdline options are able to override.
There was also a difference to ld64 which is fixed here in that ld64 will
generate an empty data in code command if requested.
rdar://problem/24472630
llvm-svn: 260191
This load command generates data in the LINKEDIT section which
is a list of ULEB128 delta's to all of the functions in the __text section.
It is then 0 terminated and pointer aligned to pad.
ld64 exposes the -function-starts and no-function-starts cmdline options
to override behaviour from the defaults based on file types.
rdar://problem/24472630
llvm-svn: 260188
This was a bug in our handling of these symbols compared to ld64.
Turns out that ld64 always marks these symbols as being not dead stripped.
llvm-svn: 260185
The atom content type enum is used as a tie breaker to sort atoms.
In that case, we want MachHeader to be before typeCode as it really will
be before the code in the final executable.
Test case to follow in the next commit or two.
llvm-svn: 260184
I found that the handling of 'L' character in an augmentation string is
wrong because 'L' means that the next byte is the length field. I could
have fixed that by just skipping the next byte, but I decided to take a
different approach.
Teaching the linker about all the types of CIE internal records just to
skip them is silly. And the code doing that is not actually executed now
(that's why the bug did not cause any issue.) It is because the 'R' field,
which we want to read, is always at beginning of the CIE. So I reduced
the code dramatically by assuming that that's always the case. I want to
see how it works in the wild. If it doesn't work, we can roll this back
(with a fix for 'L').
http://reviews.llvm.org/D16939
llvm-svn: 260073
Rui Ueyama