These stub new function were not being added to the symbol table
which in turn meant that we were crashing when trying to output
relocations against them.
Differential Revision: https://reviews.llvm.org/D78779
When discarding local symbols with --discard-all or --discard-locals,
the ones which are used in relocations should be preserved. LLD used
the simplest approach and just ignored those switches when -r or
--emit-relocs was specified.
The patch implements handling the --discard-* switches for the cases
when relocations are kept by identifying used local symbols and allowing
removing only unused ones. This makes the behavior of LLD compatible
with GNU linkers.
Differential Revision: https://reviews.llvm.org/D77807
Fixed error detected by msan. The size field of the .ARM.exidx synthetic
section needs to be initialized to at least estimation level before
calling assignAddresses as that will use the size field.
This was previously reverted in 1ca16fc4f5.
Differential Revision: https://reviews.llvm.org/D78422
This reverts commit f969c2aa65.
There are some msan buildbot failures sanitzer-x86_64-linux-fast that
I need to investigate.
Differential Revision: https://reviews.llvm.org/D78422
The contents of the .ARM.exidx section must be ordered by SHF_LINK_ORDER
rules. We don't need to know the precise address for this order, but we
do need to know the relative order of sections. We have been using the
sectionIndex for this purpose, this works when the OutputSection order
has a monotonically increasing virtual address, but it is possible to
write a linker script with non-monotonically increasing virtual address.
For these cases we need to evaluate the base address of the OutputSection
so that we can order the .ARM.exidx sections properly.
This change moves the finalisation of .ARM.exidx till after the first
call to AssignAddresses. This permits us to sort on virtual address which
is linker script safe. It also permits a fix for part of pr44824 where
we generate .ARM.exidx section for the vector table when that table is so
far away it is out of range of the .ARM.exidx section. This fix will come
in a follow up patch.
Differential Revision: https://reviews.llvm.org/D78422
Time profiler emits relative timestamps for events (the number of
microseconds passed since the start of the current process).
This patch allows combining events from different processes while
preserving their relative timing by emitting a new attribute
"beginningOfTime". This attribute contains the system time that
corresponds to the zero timestamp of the time profiler.
This has at least two use cases:
- Build systems can use this to merge time traces from multiple compiler
invocations and generate statistics for the whole build. Tools like
ClangBuildAnalyzer could also leverage this feature.
- Compilers that use LLVM as their backend by invoking llc/opt in
a child process. If such a compiler supports generating time traces
of its own events, it could merge those events with LLVM-specific
events received from llc/opt, and produce a more complete time trace.
A proof-of-concept script that merges multiple logs that
contain a synchronization point into one log:
https://github.com/broadwaylamb/merge_trace_events
Differential Revision: https://reviews.llvm.org/D78030
For a relative path in INPUT() or GROUP(), this patch changes the search order by adding the directory of the current linker script.
The new search order (consistent with GNU ld >= 2.35 regarding the new test `test/ELF/input-relative.s`):
1. the directory of the current linker script (GNU ld from Binutils 2.35 onwards; https://sourceware.org/bugzilla/show_bug.cgi?id=25806)
2. the current working directory
3. library paths (-L)
This behavior makes it convenient to replace a .so or .a with a linker script with additional input. For example, glibc
```
% cat /usr/lib/x86_64-linux-gnu/libm.a
/* GNU ld script
*/
OUTPUT_FORMAT(elf64-x86-64)
GROUP ( /usr/lib/x86_64-linux-gnu/libm-2.29.a /usr/lib/x86_64-linux-gnu/libmvec.a )
```
could be simplified as `GROUP(libm-2.29.a libmvec.a)`.
Another example is to make libc++.a a linker script:
```
INPUT(libc++.a.1 libc++abi.a)
```
Note, -l is not affected.
Reviewed By: psmith
Differential Revision: https://reviews.llvm.org/D77779
After D78301 MC no longer emits a relocation for this case. Change to use
.inst and .reloc to synthesize the same instruction and relocation. One
more test case I missed.
If there is no SHF_TLS section, there will be no PT_TLS and Out::tlsPhdr may be a nullptr.
If the symbol referenced by an R_TLS is lazy, we should treat the symbol as undefined.
Also reorganize tls-in-archive.s and tls-weak-undef.s . They do not test what they intended to test.
This diff implements:
* dylib loading (much of which is being restored from @pcc and @ruiu's
original work)
* The GOT_LOAD relocation, which allows us to load non-lazy dylib
symbols
* Basic bind opcode emission, which tells `dyld` how to populate the GOT
Differential Revision: https://reviews.llvm.org/D76252
This fixes a bug as exposed by D77807.
Add tests for {--emit-relocs,-r} x {--discard-locals,--discard-all}. They add coverage for previously undertested cases:
* STT_SECTION associated to GCed sections (`gc`)
* STT_SECTION associated to retained sections (`text`)
* STT_SECTION associated to non-SHF_ALLOC sections (`.comment`)
* STB_LOCAL in GCed sections (`unused_gc`)
Reviewed By: grimar, ikudrin
Differential Revision: https://reviews.llvm.org/D78389
D13550 added the diagnostic to address/work around a crash.
The rule was refined by D19836 (test/ELF/tls-archive.s) to exclude Lazy symbols.
https://bugs.llvm.org/show_bug.cgi?id=45598 reported another case where the current logic has a false positive:
Bitcode does not record undefined module-level inline assembly symbols
(`IRSymtab.cpp:Builder::addSymbol`). Such an undefined symbol does not
have the FB_tls bit and lld will not consider it STT_TLS. When the symbol is
later replaced by a STT_TLS Defined, lld will error "TLS attribute mismatch".
This patch fixes this false positive by allowing a STT_NOTYPE undefined
symbol to be replaced by a STT_TLS.
Considered alternative:
Moving the diagnostics to scanRelocs() can improve the diagnostics (PR36049)
but that requires a fair amount of refactoring. We will need more
RelExpr members. It requires more thoughts whether it is worthwhile.
See `test/ELF/tls-mismatch.s` for behavior differences. We will fail to
diagnose a likely runtime bug (STT_NOTYPE non-TLS relocation referencing
a TLS definition). This is probably acceptable because compiler
generated code sets symbol types properly.
Reviewed By: grimar, psmith
Differential Revision: https://reviews.llvm.org/D78438
D77522 changed --warn-backrefs to not warn for linking sandwich
problems (-ldef1 -lref -ldef2). This removed lots of false positives.
However, glibc still has some problems. libc.a defines some symbols
which are normally in libm.a and libpthread.a, e.g. __isnanl/raise.
For a linking order `-lm -lpthread -lc`, I have seen:
```
// different resolutions: GNU ld/gold select libc.a(s_isnan.o) as the definition
backward reference detected: __isnanl in libc.a(printf_fp.o) refers to libm.a(m_isnanl.o)
// different resolutions: GNU ld/gold select libc.a(raise.o) as the definition
backward reference detected: raise in libc.a(abort.o) refers to libpthread.a(pt-raise.o)
```
To facilitate deployment of --warn-backrefs, add --warn-backrefs-exclude= so that
certain known issues (which may be impractical to fix) can be whitelisted.
Deliberate choices:
* Not a comma-separated list (`--warn-backrefs-exclude=liba.a,libb.a`).
-Wl, splits the argument at commas, so we cannot use commas.
--export-dynamic-symbol is similar.
* Not in the style of `--warn-backrefs='*' --warn-backrefs=-liba.a`.
We just need exclusion, not inclusion. For easier build system
integration, we should avoid order dependency. With the current
scheme, we enable --warn-backrefs, and indivial libraries can add
--warn-backrefs-exclude=<glob> to their LDFLAGS.
Reviewed By: psmith
Differential Revision: https://reviews.llvm.org/D77512
See http://lists.llvm.org/pipermail/llvm-dev/2020-April/140549.html
For the record, GNU ld changed to 64k max page size in 2014
https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=7572ca8989ead4c3425a1500bc241eaaeffa2c89
"[RFC] ld/ARM: Increase maximum page size to 64kB"
Android driver forced 4k page size in AArch64 (D55029) and ARM (D77746).
A binary linked with max-page-size=4096 does not run on a system with a
higher page size configured. There are some systems out there that do
this and it leads to the binary getting `Killed!` by the kernel.
In the non-linker-script cases, when linked with -z noseparate-code
(default), the max-page-size increase should not cause any size
difference. There may be some VMA usage differences, though.
Reviewed By: psmith, MaskRay
Differential Revision: https://reviews.llvm.org/D77330
Use the unique filenames that are used when /lldsavetemps is passed.
After this change, module names for LTO blobs in PDBs will be unique.
Visual Studio and probably other debuggers expect module names to be
unique.
Revert some changes from 1e0b158db (2017) that are no longer necessary
after removing MSVC LTO support.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D78221
Implemented a bunch of relocations found in binaries with medium/large code model and the Local-Exec TLS model. The binaries link and run fine in Qemu.
In addition, the emulation `elf64_sparc` is now recognized.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D77672
GCC collect2 passes several options to the linker even if LTO is not used
(note, lld does not support GCC LTO). The lto-wrapper may be a relative
path (especially during development, when gcc is in a build directory), e.g.
-plugin-opt=relative/path/to/lto-wrapper
We need to ignore such options, which are currently interpreted by
cl::ParseCommandLineOptions() and will fail with `error: --plugin-opt: ld.lld: Unknown command line argument 'relative/path/to/lto-wrapper'`
because the path is apparently not an option registered by an `llvm:🆑:opt`.
See lto-plugin-ignore.s for how we interpret various -plugin-opt= options now.
Reviewed By: grimar, tejohnson
Differential Revision: https://reviews.llvm.org/D78158
Summary:
wasm-ld requires --shared-memory to be passed when the atomics feature
is enabled because historically atomic operations were only valid with
shared memories. This change relaxes that requirement for when
building relocatable objects because their memories are not
meaningful. This technically maintains the validity of object files
because the threads spec now allows atomic operations with unshared
memories, although we don't support that elsewhere in the tools yet.
This fixes and Emscripten build issue reported at
https://bugs.chromium.org/p/webp/issues/detail?id=463.
Reviewers: sbc100
Subscribers: dschuff, jgravelle-google, aheejin, sunfish, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D78072
The alignment of ARM64 range extension thunks was fixed in
7c81649219, but ARM range extension thunks, and import
and delay import thunks also need aligning (like all code on ARM
platforms).
I'm adding a test for alignment of ARM64 import thunks - not
specifically adding tests for misalignment of all of them though.
Differential Revision: https://reviews.llvm.org/D77796
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
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
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
This fixes PR# 45336.
Output sections described in a linker script as NOLOAD with no input sections would be marked as SHT_PROGBITS.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D76981
DWARF sections are typically live and not COMDAT, so they would be
treated as GC roots. Enabling DWARF would essentially keep all code with
debug info alive, preventing any section GC.
Fixes PR45273
Reviewed By: mstorsjo, MaskRay
Differential Revision: https://reviews.llvm.org/D76935
Before this patch, it wasn't possible to extend the ThinLTO threads to all SMT/CMT threads in the system. Only one thread per core was allowed, instructed by usage of llvm::heavyweight_hardware_concurrency() in the ThinLTO code. Any number passed to the LLD flag /opt:lldltojobs=..., or any other ThinLTO-specific flag, was previously interpreted in the context of llvm::heavyweight_hardware_concurrency(), which means SMT disabled.
One can now say in LLD:
/opt:lldltojobs=0 -- Use one std::thread / hardware core in the system (no SMT). Default value if flag not specified.
/opt:lldltojobs=N -- Limit usage to N threads, regardless of usage of heavyweight_hardware_concurrency().
/opt:lldltojobs=all -- Use all hardware threads in the system. Equivalent to /opt:lldltojobs=$(nproc) on Linux and /opt:lldltojobs=%NUMBER_OF_PROCESSORS% on Windows. When an affinity mask is set for the process, threads will be created only for the cores selected by the mask.
When N > number-of-hardware-threads-in-the-system, the threads in the thread pool will be dispatched equally on all CPU sockets (tested only on Windows).
When N <= number-of-hardware-threads-on-a-CPU-socket, the threads will remain on the CPU socket where the process started (only on Windows).
Differential Revision: https://reviews.llvm.org/D75153
When the debug info contains a relocation against a dead symbol, wasm-ld
may emit spurious range-list terminator entries (entries with Start==0
and End==0). This change fixes this by emitting the WasmRelocation
Addend as End value for a non-live symbol.
Reviewed by: sbc100, dblaikie
Differential Revision: https://reviews.llvm.org/D74781
Summary:
This adds a test for D76752. Now the global section comes after the
event section, and this change makes sure it is satisfied.
Reviewers: sbc100, tlively
Reviewed By: tlively
Subscribers: dschuff, jgravelle-google, sunfish, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D76823
```
// llvm-objdump -d output (before)
0: bl .-4
4: bl .+0
8: bl .+4
// llvm-objdump -d output (after) ; GNU objdump -d
0: bl 0xfffffffc / bl 0xfffffffffffffffc
4: bl 0x4
8: bl 0xc
```
Many Operand's are not annotated as OPERAND_PCREL.
They are not affected (e.g. `b .+67108860`). I plan to fix them in future patches.
Modified test/tools/llvm-objdump/ELF/PowerPC/branch-offset.s to test
address space wraparound for powerpc32 and powerpc64.
Reviewed By: sfertile, jhenderson
Differential Revision: https://reviews.llvm.org/D76591
The error previously talked about a "section header" but was actually
referring to a program header.
Reviewed by: grimar, MaskRay
Differential Revision: https://reviews.llvm.org/D76846
```
// llvm-objdump -d output (before)
400000: e8 0b 00 00 00 callq 11
400005: e8 0b 00 00 00 callq 11
// llvm-objdump -d output (after)
400000: e8 0b 00 00 00 callq 0x400010
400005: e8 0b 00 00 00 callq 0x400015
// GNU objdump -d. The lack of 0x is not ideal because the result cannot be re-assembled
400000: e8 0b 00 00 00 callq 400010
400005: e8 0b 00 00 00 callq 400015
```
In llvm-objdump, we pass the address of the next MCInst. Ideally we
should just thread the address of the current address, unfortunately we
cannot call X86MCCodeEmitter::encodeInstruction (X86MCCodeEmitter
requires MCInstrInfo and MCContext) to get the length of the MCInst.
MCInstPrinter::printInst has other callers (e.g llvm-mc -filetype=asm, llvm-mca) which set Address to 0.
They leave MCInstPrinter::PrintBranchImmAsAddress as false and this change is a no-op for them.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D76580
Added support for /map and /map:[filepath].
The output was derived from Microsoft's Link.exe output when using that same option.
Note that /MAPINFO support was not added.
The previous implementation of MapFile.cpp/.h was meant for /lldmap, and was renamed to LLDMapFile.cpp/.h
MapFile.cpp/.h is now for /MAP
However, a small fix was added to lldmap, replacing a std::sort with std::stable_sort to enforce reproducibility.
Differential Revision: https://reviews.llvm.org/D70557
This behavior matches GNU ld and seems reasonable.
```
// If a SECTIONS command is not specified
.text.* -> .text
.rodata.* -> .rodata
.init_array.* -> .init_array
```
A proposed Linux feature CONFIG_FG_KASLR may depend on the GNU ld behavior.
Reword a comment about -z keep-text-section-prefix and a comment about
CommonSection (deleted by rL286234).
Reviewed By: grimar
Differential Revision: https://reviews.llvm.org/D75225
This essentially drops the change by r288021 (discussed with Georgii Rymar
and Peter Smith and noted down in the release note of lld 10).
GNU ld>=2.31 enables -z separate-code by default for Linux x86. By
default (in the absence of a PHDRS command) a readonly PT_LOAD is
created, which is different from its traditional behavior.
Not emulating GNU ld's traditional behavior is good for us because it
improves code consistency (we create a readonly PT_LOAD in the absence
of a SECTIONS command).
Users can add --no-rosegment to restore the previous behavior (combined
readonly and read-executable sections in a single RX PT_LOAD).
Fixes https://bugs.llvm.org/show_bug.cgi?id=44903
It is about the following case:
```
SECTIONS {
.foo : { *(.foo) } =0x90909090
/DISCARD/ : { *(.bar) }
}
```
Here while parsing the fill expression we treated the
"/" of "/DISCARD/" as operator.
With this change, suggested by Fangrui Song, we do
not allow expressions with operators (e.g. "0x1100 + 0x22")
that are not wrapped into round brackets. It should not
be an issue for users, but helps to resolve parsing ambiguity.
Differential revision: https://reviews.llvm.org/D74687
Follow-up for D74433
What the function returns are almost standard BFD names, except that "ELF" is
in uppercase instead of lowercase.
This patch changes "ELF" to "elf" and changes ARM/AArch64 to use their BFD names.
MIPS and PPC64 have endianness differences as well, but this patch does not intend to address them.
Advantages:
* llvm-objdump: the "file format " line matches GNU objdump on ARM/AArch64 objects
* "file format " line can be extracted and fed into llvm-objcopy -O literally.
(https://github.com/ClangBuiltLinux/linux/issues/779 has such a use case)
Affected tools: llvm-readobj, llvm-objdump, llvm-dwarfdump, MCJIT (internal implementation detail, not exposed)
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D76046
When emitting PDBs, the TypeStreamMerger class is used to merge .debug$T records from the input .OBJ files into the output .PDB stream.
Records in .OBJs are not required to be aligned on 4-bytes, and "The Netwide Assembler 2.14" generates non-aligned records.
When compiling with -DLLVM_ENABLE_ASSERTIONS=ON, an assert was triggered in MergingTypeTableBuilder when non-ghash merging was used.
With ghash merging there was no assert.
As a result, LLD could potentially generate a non-aligned TPI stream.
We now align records on 4-bytes when record indices are remapped, in TypeStreamMerger::remapIndices().
Differential Revision: https://reviews.llvm.org/D75081
Hexagon ABI specifies that call x@gdplt is transformed to call __tls_get_addr.
Example:
call x@gdplt
is changed to
call __tls_get_addr
When x is an external tls variable.
Differential Revision: https://reviews.llvm.org/D74443
Any OUTPUT_FORMAT in a linker script overrides the emulation passed on
the command line, so record the passed bfdname and use that in the error
message about incompatible input files.
This prevents confusing error messages. For example, if you explicitly
pass `-m elf_x86_64` to LLD but accidentally include a linker script
which sets `OUTPUT_FORMAT(elf32-i386)`, LLD would previously complain
about your input files being compatible with elf_x86_64, which isn't the
actual issue, and is confusing because the input files are in fact
x86-64 ELF files.
Interestingly enough, this also prevents a segfault! When we don't pass
`-m` and we have an object file which is incompatible with the
`OUTPUT_FORMAT` set by a linker script, the object file is checked for
compatibility before it's added to the objectFiles vector.
config->emulation, objectFiles, and sharedFiles will all be empty, so
we'll attempt to access bitcodeFiles[0], but bitcodeFiles is also empty,
so we'll segfault. This commit prevents the segfault by adding
OUTPUT_FORMAT as a possible source of machine configuration, and it also
adds an llvm_unreachable to diagnose similar issues in the future.
Differential Revision: https://reviews.llvm.org/D76109
-M output can be useful when diagnosing an "error: output file too large" problem (emitted in openFile()).
I just ran into such a situation where I had to debug an erronerous
Linux kernel linker script. It tried to create a file larger than
INT64_MAX bytes.
This patch could have helped https://bugs.llvm.org/show_bug.cgi?id=44715 as well.
Reviewed By: grimar
Differential Revision: https://reviews.llvm.org/D75966
Sam Clegg