Summary:
A previous change (53211a) had updated the argument parsing to handle
large max memories, but 4294967296 would still wrap to zero after the
options were parsed. This change updates the configuration to use a
64-bit integer to store the max memory to avoid that overflow.
Reviewers: sbc100
Subscribers: dschuff, jgravelle-google, aheejin, sunfish, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D77437
This patch changes the reproduce tests so that they no longer extract
the "long" paths of the generated reproduce tar archives. This
extraction prevented them from being run on Windows due to potential
issues relating to the Windows path length limit.
This patch also reduces the use of diff in these tests, as this was
raised as a performance concern in review D77659 and deemed unnecessary.
Differential Revision: https://reviews.llvm.org/D77750
The R_ARM_ALU_PC_G0 and R_ARM_LDR_PC_G0 relocations are used by the
ADR and LDR pseudo instructions, and are the basis of the group
relocations that can load an arbitrary constant via a series of add, sub
and ldr instructions.
The relocations need to be obtained via the .reloc directive.
R_ARM_ALU_PC_G0 is much more complicated as the add/sub instruction uses
a modified immediate encoding of an 8-bit immediate rotated right by an
even 4-bit field. This means that the range of representable immediates
is sparse. We extract the encoding and decoding functions for the modified
immediate from llvm/lib/Target/ARM/MCTargetDesc/ARMAddressingModes.h as
this header file is not accessible from LLD. Duplication of code isn't
ideal, but as these are well-defined mathematical functions they are
unlikely to change.
Differential Revision: https://reviews.llvm.org/D75349
Summary:
/PDBSTREAM:<name>=<file> adds the contents of <file> to stream <name> in the resulting PDB.
This allows native uses with workflows that (for example) add srcsrv streams to PDB files to provide a location for the build's source files.
Results should be equivalent to linking with lld-link, then running Microsoft's pdbstr tool with the command line:
pdbstr.exe -w -p:<PDB LOCATION> -s:<name> -i:<file>
except in cases where the named stream overlaps with a default named stream, such as "/names". In those cases, the added stream will be overridden, making the /pdbstream option a no-op.
Reviewers: thakis, rnk
Reviewed By: thakis
Differential Revision: https://reviews.llvm.org/D77310
This is an alternative design to D77512.
D45195 added --warn-backrefs to detect
* A. certain input orders which GNU ld either errors ("undefined reference")
or has different resolution semantics
* B. (byproduct) some latent multiple definition problems (-ldef1 -lref -ldef2) which I
call "linking sandwich problems". def2 may or may not be the same as def1.
When an archive appears more than once (-ldef -lref -ldef), lld and GNU
ld may have the same resolution but --warn-backrefs may warn. This is
not uncommon. For example, currently lld itself has such a problem:
```
liblldCommon.a liblldCOFF.a ... liblldCommon.a
_ZN3lld10DWARFCache13getDILineInfoEmm in liblldCOFF.a refers to liblldCommon.a(DWARF.cpp.o)
libLLVMSupport.a also appears twice and has a similar warning
```
glibc has such problems. It is somewhat destined because of its separate
libc/libpthread/... and arbitrary grouping. The situation is getting
improved over time but I have seen:
```
-lc __isnanl references -lm
-lc _IO_funlockfile references -lpthread
```
There are also various issues in interaction with other runtime
libraries such as libgcc_eh and libunwind:
```
-lc __gcc_personality_v0 references -lgcc_eh
-lpthread __gcc_personality_v0 references -lgcc_eh
-lpthread _Unwind_GetCFA references -lunwind
```
These problems are actually benign. We want --warn-backrefs to focus on
its main task A and defer task B (which is also useful) to a more
specific future feature (see gold --detect-odr-violations and
https://bugs.llvm.org/show_bug.cgi?id=43110).
Instead of warning immediately, we store the message and only report it
if no subsequent lazy definition exists.
The use of the static variable `backrefDiags` is similar to `undefs` in
Relocations.cpp
Reviewed By: grimar
Differential Revision: https://reviews.llvm.org/D77522
SymbolAssignment::addr stores the location counter. The type should be
uint64_t instead of unsigned. The upper half of the address space is
commonly used by operating system kernels.
Similarly, SymbolAssignment::size should be an uint64_t. A kernel linker
script can move the location counter from 0 to the upper half of the
address space.
Reviewed By: grimar
Differential Revision: https://reviews.llvm.org/D77445
This is part of the Propeller framework to do post link code layout
optimizations. Please see the RFC here:
https://groups.google.com/forum/#!msg/llvm-dev/ef3mKzAdJ7U/1shV64BYBAAJ and the
detailed RFC doc here:
https://github.com/google/llvm-propeller/blob/plo-dev/Propeller_RFC.pdf
This patch adds lld support for basic block sections and performs relaxations
after the basic blocks have been reordered.
After the linker has reordered the basic block sections according to the
desired sequence, it runs a relaxation pass to optimize jump instructions.
Currently, the compiler emits the long form of all jump instructions. AMD64 ISA
supports variants of jump instructions with one byte offset or a four byte
offset. The compiler generates jump instructions with R_X86_64 32-bit PC
relative relocations. We would like to use a new relocation type for these jump
instructions as it makes it easy and accurate while relaxing these instructions.
The relaxation pass does two things:
First, it deletes all explicit fall-through direct jump instructions between
adjacent basic blocks. This is done by discarding the tail of the basic block
section.
Second, If there are consecutive jump instructions, it checks if the first
conditional jump can be inverted to convert the second into a fall through and
delete the second.
The jump instructions are relaxed by using jump instruction mods, something
like relocations. These are used to modify the opcode of the jump instruction.
Jump instruction mods contain three values, instruction offset, jump type and
size. While writing this jump instruction out to the final binary, the linker
uses the jump instruction mod to determine the opcode and the size of the
modified jump instruction. These mods are required because the input object
files are memory-mapped without write permissions and directly modifying the
object files requires copying these sections. Copying a large number of basic
block sections significantly bloats memory.
Differential Revision: https://reviews.llvm.org/D68065
Fixes https://bugs.llvm.org/show_bug.cgi?id=45391
The LTO code generator happens after version script scanning and may
create references which will fetch some lazy symbols.
Currently a version script does not assign VER_NDX_LOCAL to lazy symbols
and such symbols will be made global after they are fetched.
Change findByVersion and findAllByVersion to work on lazy symbols.
For unfetched lazy symbols, we should keep them non-local (D35263).
Check isDefined() in computeBinding() as a compensation.
This patch fixes a companion bug that --dynamic-list does not export
libcall fetched symbols.
Reviewed By: grimar
Differential Revision: https://reviews.llvm.org/D77280
finalizeSynthetic(in.symTab) calls sortSymTabSymbols() to order local
symbols before non-local symbols.
The newly added tests ensure that thunk symbols are added before
finalizeSynthetic(in.symTab), otherwise .symtab would be out of order.
A PC-relative relocation referencing a non-preemptible absolute symbol
(due to STT_TLS) is not representable in -pie/-shared mode.
Differential Revision: https://reviews.llvm.org/D77021
In the near future llvm-mc will resolve the fixups that generate
R_ARM_THUMB_PC8 and R_ARM_THUMB_PC12 at assembly time (see comments in
D72892), and forbid inter-section references. Change the LLD tests for
these relocations to use .inst and .reloc to avoid LLD tests failing when
this happens. The tests generate the same instructions, relocations
and symbols.
I will need to make equivalent changes for D75349 Arm equivalent
relocations, but this is still in review so these don't need changing
before llvm-mc.
Differential Revision: https://reviews.llvm.org/D77200
The aliased options in the --help output use double dashes. It is
inconsistent to have single-dashed messages. Additionally, -l and -t are
common short options and single-dashed forms prefixed with them can
cause confusion.
In most cases, LLD prints its multiline diagnostic messages starting
additional lines with ">>> ". That greatly helps external tools to parse
the output, simplifying combining several lines of the log back into one
message. The patch fixes the only message I found that does not follow
the common pattern.
Differential Revision: https://reviews.llvm.org/D77132
When reporting an "undefined symbol" diagnostic:
* We don't print @ for the reference.
* We don't print @ or @@ for the definition. https://bugs.llvm.org/show_bug.cgi?id=45318
This can lead to confusing diagnostics:
```
// foo may be foo@v2
ld.lld: error: undefined symbol: foo
>>> referenced by t1.o:(.text+0x1)
// foo may be foo@v1 or foo@@v1
>>> did you mean: foo
>>> defined in: t.so
```
There are 2 ways a symbol in symtab may get truncated:
* A @@ definition may be truncated *early* by SymbolTable::insert().
The name ends with a '\0'.
* A @ definition/reference may be truncated *later* by Symbol::parseSymbolVersion().
The name ends with a '@'.
This patch detects the second case and improves the diagnostics. The first case is
not improved but the second case is sufficient to make diagnostics not confusing.
Reviewed By: ruiu
Differential Revision: https://reviews.llvm.org/D76999
This matches the behaviour of the ELF driver.
Also move the `createFiles` to be `checkConfig` and report `no input
files` there. Again this is mostly to match the structure of the ELF
linker better.
Differential Revision: https://reviews.llvm.org/D76960
Summary:
This is the first commit for the new Mach-O backend, designed to roughly
follow the architecture of the existing ELF and COFF backends, and
building off work that @ruiu and @pcc did in a branch a while back. Note
that this is a very stripped-down commit with the bare minimum of
functionality for ease of review. We'll be following up with more diffs
soon.
Currently, we're able to generate a simple "Hello World!" executable
that runs on OS X Catalina (and possibly on earlier OS X versions; I
haven't tested them). (This executable can be obtained by compiling
`test/MachO/relocations.s`.) We're mocking out a few load commands to
achieve this -- for example, we can't load dynamic libraries, but
Catalina requires binaries to be linked against `dyld`, so we hardcode
the emission of a `LC_LOAD_DYLIB` command. Other mocked out load
commands include LC_SYMTAB and LC_DYSYMTAB.
Differential Revision: https://reviews.llvm.org/D75382
--no-threads is a name copied from gold.
gold has --no-thread, --thread-count and several other --thread-count-*.
There are needs to customize the number of threads (running several lld
processes concurrently or customizing the number of LTO threads).
Having a single --threads=N is a straightforward replacement of gold's
--no-threads + --thread-count.
--no-threads is used rarely. So just delete --no-threads instead of
keeping it for compatibility for a while.
If --threads= is specified (ELF,wasm; COFF /threads: is similar),
--thinlto-jobs= defaults to --threads=,
otherwise all available hardware threads are used.
There is currently no way to override a --threads={1,2,...}. It is still
a debate whether we should use --threads=all.
Reviewed By: rnk, aganea
Differential Revision: https://reviews.llvm.org/D76885
The default GNU linker script uses the following idiom for the array
sections. I'll use .init_array here, but this also applies to
.preinit_array and .fini_array sections.
.init_array :
{
PROVIDE_HIDDEN (__init_array_start = .);
KEEP (*(.init_array))
PROVIDE_HIDDEN (__init_array_end = .);
}
The C-library will take references to the _start and _end symbols to
process the array. This will make LLD keep the OutputSection even if there
are no .init_array sections. As the current check for RELRO uses the
section type for .init_array the above example with no .init_array
InputSections fails the checks as there are no .init_array sections to give
the OutputSection a type of SHT_INIT_ARRAY. This often leads to a
non-contiguous RELRO error message.
The simple fix is to a textual section match as well as a section type
match.
Differential Revision: https://reviews.llvm.org/D76915
This test covers the case where --gc-sections is used when there are
many sections. In particular, it ensures that there is no adverse
interaction with common and absolute symbols.
Reviewed by: MaskRay, grimar
Differential Revision: https://reviews.llvm.org/D76003
The test had a few style issues, and I noticed a hole in the coverage
(namely that the search order wasn't tested). Adding cases for the hole
in turn meant other cases weren't important.
The .so test case isn't important, since the code is shared code, so
I've removed it. Additionally, I've modified the usage of the "bar"
directive to show that an unneeded library must still be present, or the
link will fail, even though it isn't linked in.
Reviewed by: MaskRay, grimar
Differential Revision: https://reviews.llvm.org/D76851
Leverage ARM ELF build attribute section to create ELF attribute section
for RISC-V. Extract the common part of parsing logic for this section
into ELFAttributeParser.[cpp|h] and ELFAttributes.[cpp|h].
Differential Revision: https://reviews.llvm.org/D74023
As of a while ago, lld groups all undefined references to a single
symbol in a single diagnostic. Back then, I made it so that we
print up to 10 references to each undefined symbol.
Having used this for a while, I never wished there were more
references, but I sometimes found that this can print a lot of
output. lld prints up to 10 diagnostics by default, and if
each has 10 references (which I've seen in practice), and each
undefined symbol produces 2 (possibly very long) lines of output,
that's over 200 lines of error output.
Let's try it with just 3 references for a while and see how
that feels in practice.
Differential Revision: https://reviews.llvm.org/D77017
Currently, `error: incompatible section flags for .rodata` is reported
when we mix SHF_LINK_ORDER and non-SHF_LINK_ORDER sections in an output section.
This is overconstrained. This patch allows mixed flags with the
requirement that SHF_LINK_ORDER sections must be contiguous. Mixing
flags is used by Linux aarch64 (https://github.com/ClangBuiltLinux/linux/issues/953)
.init.data : { ... KEEP(*(__patchable_function_entries)) ... }
When the integrated assembler is enabled, clang's -fpatchable-function-entry=N[,M]
implementation sets the SHF_LINK_ORDER flag (D72215) to fix a number of
garbage collection issues.
Strictly speaking, the ELF specification does not require contiguous
SHF_LINK_ORDER sections but for many current uses of SHF_LINK_ORDER like
.ARM.exidx/__patchable_function_entries there has been a requirement for
the sections to be contiguous on top of the requirements of the ELF
specification.
This patch also imposes one restriction: SHF_LINK_ORDER sections cannot
be separated by a symbol assignment or a BYTE command. Not allowing BYTE
is a natural extension that a non-SHF_LINK_ORDER cannot be a separator.
Symbol assignments can delimiter the contents of SHF_LINK_ORDER
sections. Allowing SHF_LINK_ORDER sections across symbol assignments
(especially __start_/__stop_) can make things hard to explain. The
restriction should not be a problem for practical use cases.
Reviewed By: psmith
Differential Revision: https://reviews.llvm.org/D77007
Sam Clegg