Summary:
While the generic ABI requires notes to be 8-byte aligned in ELF64, many
vendor-specific notes (from Linux, NetBSD, Solaris, etc) use 4-byte
alignment.
In a PT_NOTE segment, if 4-byte aligned notes are followed by an 8-byte
aligned note, the possible 4-byte padding may make consumers fail to
parse the 8-byte aligned note. See PR41000 for a recent report about
.note.gnu.property (NT_GNU_PROPERTY_TYPE_0).
(Note, for NT_GNU_PROPERTY_TYPE_0, the consumers should probably migrate
to PT_GNU_PROPERTY, but the alignment issue affects other notes as well.)
To fix the issue, don't mix notes with different alignments in one
PT_NOTE. If compilers emit 4-byte aligned notes before 8-byte aligned
notes, we'll create at most 2 segments.
sh_size%sh_addralign=0 is actually implied by the rule for linking
unrecognized sections (in generic ABI), so we don't have to check that.
Notes that match in name, type and attribute flags are concatenated into
a single output section. The compilers have to ensure
sh_size%sh_addralign=0 to make concatenated notes parsable.
An alternative approach is to create a PT_NOTE for each SHT_NOTE, but
we'll have to incur the sizeof(Elf64_Phdr)=56 overhead every time a new
note section is introduced.
Reviewers: ruiu, jakehehrlich, phosek, jhenderson, pcc, espindola
Subscribers: emaste, arichardson, krytarowski, fedor.sergeev, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61296
llvm-svn: 359853
Summary:
The gold plugin behavior (creating empty index files for lazy bitcode
files) was added in D46034, but it missed the case when there is no
non-lazy bitcode files, e.g.
ld.lld -shared crti.o crtbeginS.o --start-lib bitcode.o --end-lib ...
crti.o crtbeginS.o are not bitcode, but our distributed build system
wants bitcode.o.thinlto.bc to confirm all expected outputs are created
based on all of the modules provided to the linker.
Differential Revision: https://reviews.llvm.org/D61420
llvm-svn: 359788
This improves readability and the behavior is consistent with GNU objdump.
The new test test/tools/llvm-objdump/X86/disassemble-section-name.s
checks we print newlines before and after "Disassembly of section ...:"
Differential Revision: https://reviews.llvm.org/D61127
llvm-svn: 359668
Also change some options that have different semantics (cause confusion) in llvm-readelf mode:
-s => -S
-t => --symbols
-sd => --section-data
llvm-svn: 359651
/DISCARD/ output sections were being treated as orphans. As a result, if
a /DISCARD/ output section has been assigned a PHDR, it could cause
incorrect assignment of sections to segments.
Differential Revision: https://reviews.llvm.org/D61186
llvm-svn: 359565
This is a follow up to r358979 which made findOrphanPos only consider
live sections. Unfortunately, this required change to getRankProximity,
used by findOrphanPos, was missed.
Differential Revision: https://reviews.llvm.org/D61197
llvm-svn: 359554
This is https://bugs.llvm.org//show_bug.cgi?id=38750.
If script references empty sections in LOADADDR/ADDR commands
.empty : { *(.empty ) }
.text : AT(LOADADDR (.empty) + SIZEOF (.empty)) { *(.text) }
then an empty section will be removed and LOADADDR/ADDR will evaluate to null.
It is not that user may expect from using of the generic script, what is a common case.
Differential revision: https://reviews.llvm.org/D54621
llvm-svn: 359279
This removes one more binary object from the inputs and fixes the
test case description.
Previously it said that:
"symbol-index.elf has incorrect type of .symtab section.
There is no symbol bodies because of that and any symbol index becomes incorrect."
But the real reason of the failture was not the incorrect type of a symbol table,
but invalid index of the symbol used in a relocation, what happened because
previous test tried to read .symtab as a SHT_RELA section.
llvm-svn: 359197
Summary:
We don't take localentry offset into account, and thus may fail to
create a long branch when the gap is just a few bytes smaller than 2^25.
relocation R_PPC64_REL24 out of range: 33554432 is not in [-33554432, 33554431]
relocation R_PPC64_REL24 out of range: 33554436 is not in [-33554432, 33554431]
Fix that by adding the offset to the symbol VA.
Differential Revision: https://reviews.llvm.org/D61058
llvm-svn: 359094
dynamic-section-sh_size.elf was introduced in D25090.
Now it is possible to use yaml2obj instead.
That is what this patch does.
Also I added one more case of a possibly broken .dynamic
section just in case.
llvm-svn: 358990
file-class.a was used to diagnose the "corrupted ELF file: invalid file class"
error when the object was fetched from the archive.
file-class.a contained an object of 16 bytes size. I replaced it with
an echo call (because it is impossible to use yaml2obj for that, and I am
not sure it is worth to support), and also increased its size to 18 bytes.
That allowed to also test a case when such object is a regular input and not an
archive member (we have a bit different logic for these cases).
llvm-svn: 358985
This fixes an issue where a symbol only section at the start of a
PT_LOAD segment, causes incorrect alignment of the file offset for the
start of the segment which results in the output of an invalid ELF.
SHT_PROGBITS was the default output section type in the past.
Differential Revision: https://reviews.llvm.org/D60131
llvm-svn: 358981
Various improvement:
Some offsets in disassembly are incorrect after several layout adjustment. Fix them.
llvm-objdump -D should not be used. -D dumps unrelated non-text sections. Replace them with llvm-objdump -d, llvm-readelf -x, etc
Many llvm-objdump -d tests use {{.*}} . Add the option --no-show-raw-insn to avoid check hex bytes.
ppc64-long-branch.s does not need a shared object. Delete it.
Make ppc64-ifunc.s check 2 ifuncs.
Reviewers: ruiu, espindola
Subscribers: emaste, nemanjai, arichardson, kbarton, jsji, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60998
llvm-svn: 358975
It was initially introduced in D25229 to report the "zero option descriptor size"
error message. In following commits it was broken and did not report this
error anymore. I think that happened because elf object was a result of fuzzing
and it was broken in many ways.
This patch converts this test to a YAML, removes a binary and hence fixes the
original intention.
llvm-svn: 358972
rL358960 "[llvm-mc] - Properly set the the address align field of the compressed sections."
changed the sh_addralign field of the "zlib" compressed debug sections.
llvm-svn: 358961
Summary:
Fixes PR35242. A simplified reproduce:
thread_local int i; int f() { return i; }
% {g++,clang++} -fPIC -shared -ftls-model=local-dynamic -fuse-ld=lld a.cc
ld.lld: error: can't create dynamic relocation R_X86_64_DTPOFF32 against symbol: i in readonly segment; recompile object files with -fPIC or pass '-Wl,-z,notext' to allow text relocations in the output
In isStaticLinkTimeConstant(), Syn.IsPreemptible is true, so it is not
seen as a constant. The error is then issued in processRelocAux().
A symbol of the local-dynamic TLS model cannot be preempted but it can
preempt symbols of the global-dynamic TLS model in other DSOs.
So it makes some sense that the variable is not static.
This patch fixes the linking error by changing getRelExpr() on
R_386_TLS_LDO_32 and R_X86_64_DTPOFF{32,64} from R_ABS to R_DTPREL.
R_PPC64_DTPREL_* and R_MIPS_TLS_DTPREL_* need similar fixes, but they are not handled in this patch.
As a bonus, we use `if (Expr == R_ABS && !Config->Shared)` to find
ld-to-le opportunities. R_ABS is overloaded here for such STT_TLS symbols.
A dedicated R_DTPREL is clearer.
Differential Revision: https://reviews.llvm.org/D60945
llvm-svn: 358870
Another attempt to land the changes in debug line header to prevent duplicate
files in Dwarf 5. I rolled back my previous commit because of a mistake in
generating the object file in a test. Meanwhile, I addressed some offline
comments and changed the implementation; the largest difference is that
MCDwarfLineTableHeader does not keep DwarfVersion but gets it as a parameter. I
also merged the patch to fix two lld tests that will strt to fail into this
patch.
Original Commit:
https://reviews.llvm.org/D59515
Original Message:
Motivation: In previous dwarf versions, file name indexes started from 1, and
the primary source file was not explicit. Dwarf 5 standard (6.2.4) prescribes
the primary source file to be explicitly given an entry with an index number 0.
The current implementation honors the specification by just duplicating the
main source file, once with index number 0, and later maybe with another
index number. While this is compliant with the letter of the standard, the
duplication causes problems for consumers of this information such as lldb.
(Some files are duplicated, where only some of them have a line table although
all refer to the same file)
With this change, dwarf 5 debug line section files always start from 0, and
the zeroth entry is not duplicated whenever possible. This requires different
handling of dwarf 4 and dwarf 5 during generation (e.g. when a function returns
an index zero for a file name, it signals an error in dwarf 4, but not in dwarf
5) However, I think the minor complication is worth it, because it enables all
consumers (lldb, gdb, dwarfdump, objdump, and so on) to treat all files in the
file name list homogenously.
llvm-svn: 358732
This is https://bugs.llvm.org//show_bug.cgi?id=39857.
I added the comment with much more details to the bug page,
the short version is below.
The following script and code demonstrates the issue:
aliasto__text = __text;
SECTIONS {
.text 0x1000 : { __text = . ; *(.text) }
}
...
call aliasto__text
LLD fails with "cannot refer to absolute symbol: aliasto__text" error.
It happens because at the moment of scanning the relocations
we do not yet assign the correct/final/any section value for the symbol aliasto__text.
I made a change to Relocations.cpp to fix that.
Also, I had to remove the symbol-location.s test case completely, because now it does not
trigger any error. Since now all linker scripts symbols are resolved to constants, no
errors can be triggered at all it seems. I checked that it is consistent with the behavior
of bfd and gold (they do not trigger errors for the case from symbol-location.s), so it should
be OK. I.e. at least it is probably not the best possible, but natural behavior we obtained.
Differential revision: https://reviews.llvm.org/D55423
llvm-svn: 358652
Summary:
If the output section contains only symbol assignments, we copy flags
from the previous sections. Don't set SHF_ALLOC if NonAlloc is true.
We also have to change the type from SHT_NOBITS to SHT_PROGBITS.
In ld.bfd, bfd_elf_get_default_section_type maps non-alloctable sections to SHT_PROGBITS.
Non-alloctable SHT_NOBITS sections do not make sense.
Fixes PR38626
Differential Revision: https://reviews.llvm.org/D59986
llvm-svn: 358650
This generalizes code and also fixes the broken behavior shown in
one of our test cases for some targets, like x86-64.
The issue occurs when the forward declarations are used in the script.
One of the samples is:
SECTIONS {
foo = ADDR(.text) - ABSOLUTE(ADDR(.text));
};
In that case, we have a broken output when output target does
not use thunks. That happens because thunks creating code
(called from maybeAddThunks)
calls Script->assignAddresses() at least one more time,
what fixups the values. As a result final symbols values can
be different on AArch64 and x86, for example.
In this patch, I generalize and rename maybeAddThunks to
finalizeAddressDependentContent and now it is used and called
by all targets.
Differential revision: https://reviews.llvm.org/D55550
llvm-svn: 358646
Patch by Gabriel Smith.
The address for a section would be evaluated before the region was
switched to. Because of this, the position within the region would not
be updated. After the region is swapped to the dot would be set to the
out of date position within the region, undoing the section address
evaluation.
To fix this, the region is swapped to before the section's address is
evaluated. As part of the fallout of this, expandMemoryRegions needed
to be gated in setDot on the condition that the evaluated address is
less than the dot. This is for the case where sections are not listed
from lowest address to highest address.
Finally, a test for the case where sections are listed "out of order"
was added.
Differential Revision: https://reviews.llvm.org/D60744
llvm-svn: 358638
The typo was introduced to llvm MC in rL204769 (fixed in rL358247) and then to lld.
Also, for relocatable-many-sections.s, the size of .symtab changed at some point and the formula needs update.
llvm-svn: 358248
Patch by Robert O'Callahan.
Rust projects tend to link in all object files from all dependent
libraries and rely on --gc-sections to strip unused code and data.
Unfortunately --gc-sections doesn't currently strip any debuginfo
associated with GC'ed sections, so lld links in the full debuginfo from
all dependencies even if almost all that code has been discarded. See
https://github.com/rust-lang/rust/issues/56068 for some details.
Properly stripping debuginfo for discarded sections would be difficult,
but a simple approach that helps significantly is to mark debuginfo
sections as live only if their associated object file has at least one
live code/data section. This patch does that. In a (contrived but not
totally artificial) Rust testcase linked above, it reduces the final
binary size from 46MB to 5.1MB.
Differential Revision: https://reviews.llvm.org/D54747
llvm-svn: 358069
Previously the tests in lld for RISC-V were given in yaml format as
LLVM's RISC-V assembler support was incomplete. Now that the
assembler/disassembler has matured we can rewrite all tests to use
LLVM's tools.
Differential Revision: https://reviews.llvm.org/D60415
llvm-svn: 357996
For partitions I intend to use the same set of version indexes in
each partition for simplicity. Since each partition will need its own
VersionNeedSection this will require moving the verneed tracking out of
VersionNeedSection. The way I've done this is to move most of the tracking
into SharedFile. What will eventually become the per-partition tracking
still lives in VersionNeedSection.
As a bonus the code gets a little simpler and more consistent with how we
handle verdef.
Differential Revision: https://reviews.llvm.org/D60307
llvm-svn: 357926
Previously, we drop symbols starting with .L from the symbol table, so
if there is a relocation that refers a .L symbol, it ended up
referencing a null -- which happened to be interpreted as an absolute
symbol.
This patch copies all symbols including local ones if -emit-reloc is
given.
Fixes https://bugs.llvm.org/show_bug.cgi?id=41385
Differential Revision: https://reviews.llvm.org/D60306
llvm-svn: 357885
Recommit r356666 with fixes for buildbot failure, as well as handling for
--emit-relocs, which we decide not to emit any relocation sections as the
table is already position independent and an offline tool can deduce the
relocations.
Instead of creating extra Synthetic .ARM.exidx sections to account for
gaps in the table, create a single .ARM.exidx SyntheticSection that can
derive the contents of the gaps from a sorted list of the executable
InputSections. This has the benefit of moving the ARM specific code for
SyntheticSections in SHF_LINK_ORDER processing and the table merging code
into the ARM specific SyntheticSection. This also makes it easier to create
EXIDX_CANTUNWIND table entries for executable InputSections that don't
have an associated .ARM.exidx section.
Fixes pr40277
Differential Revision: https://reviews.llvm.org/D59216
llvm-svn: 357160
Patch by Tiancong Wang.
In D36351, Call-Chain Clustering (C3) heuristic is implemented with
option --call-graph-ordering-file <file>.
This patch adds a flag --print-symbol-order=<file> to LLD, and when
specified, it prints out the symbols ordered by the heuristics to the
file. The symbols printout is helpful to those who want to understand
the heuristics and want to reproduce the ordering with
--symbol-ordering-file in later pass.
Differential Revision: https://reviews.llvm.org/D59311
llvm-svn: 357133
No longer require workarounds for output to "-" (stdout) for
Windows. These workarounds were just hiding the actual problem which has
been fixed in r357058.
Differential Revision: https://reviews.llvm.org/D59824
llvm-svn: 357072
This reverts commit rL357020
Reason: rL357018, which this commit depend on breaks the test:
llvm/test/tools/llvm-objdump/embedded-source.test on some architectures.
llvm-svn: 357025
Reapply rL356943; the previous attempt was reverted because the patch rL356941
that this depended on had broken a test.
Original commit message:
[lld] Prevent duplicate files in debug line header in dwarf 5.
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59671
llvm-svn: 357020
Summary:
This should address remaining issues discussed in PR36555.
Currently R_GOT*_FROM_END are exclusively used by x86 and x86_64 to
express relocations types relative to the GOT base. We have
_GLOBAL_OFFSET_TABLE_ (GOT base) = start(.got.plt) but end(.got) !=
start(.got.plt)
This can have problems when _GLOBAL_OFFSET_TABLE_ is used as a symbol, e.g.
glibc dl_machine_dynamic assumes _GLOBAL_OFFSET_TABLE_ is start(.got.plt),
which is not true.
extern const ElfW(Addr) _GLOBAL_OFFSET_TABLE_[] attribute_hidden;
return _GLOBAL_OFFSET_TABLE_[0]; // R_X86_64_GOTPC32
In this patch, we
* Change all GOT*_FROM_END to GOTPLT* to fix the problem.
* Add HasGotPltOffRel to denote whether .got.plt should be kept even if
the section is empty.
* Simplify GotSection::empty and GotPltSection::empty by setting
HasGotOffRel and HasGotPltOffRel according to GlobalOffsetTable early.
The change of R_386_GOTPC makes X86::writePltHeader simpler as we don't
have to compute the offset start(.got.plt) - Ebx (it is constant 0).
We still diverge from ld.bfd (at least in most cases) and gold in that
.got.plt and .got are not adjacent, but the advantage doing that is
unclear.
Reviewers: ruiu, sivachandra, espindola
Subscribers: emaste, mehdi_amini, arichardson, dexonsmith, jdoerfert, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59594
llvm-svn: 356968
Summary:
Changes to a couple of tests that will start failing after https://reviews.llvm.org/D59515 is submitted.
Reviewers: echristo, ruiu, espindola
Reviewed By: echristo, ruiu
Subscribers: emaste, arichardson, MaskRay, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59671
llvm-svn: 356943
There is a reproducible buildbot failure (segfault) on the 2 stage
clang-cmake-armv8-lld bot. Reverting while I investigate.
Differential Revision: https://reviews.llvm.org/D59216
llvm-svn: 356684
Instead of creating extra Synthetic .ARM.exidx sections to account for
gaps in the table, create a single .ARM.exidx SyntheticSection that can
derive the contents of the gaps from a sorted list of the executable
InputSections. This has the benefit of moving the ARM specific code for
SyntheticSections in SHF_LINK_ORDER processing and the table merging code
into the ARM specific SyntheticSection. This also makes it easier to create
EXIDX_CANTUNWIND table entries for executable InputSections that don't
have an associated .ARM.exidx section.
Fixes pr40277
Differential Revision: https://reviews.llvm.org/D59216
llvm-svn: 356666
D58391 changed the LTO pipelines to add the tailcall elimination pass.
This caused three LLD tests to fail.
Differential Revision: https://reviews.llvm.org/D59604
llvm-svn: 356593
Summary:
This implements Rui Ueyama's idea in PR39044.
I've checked that ld.bfd and gold do not have the power-of-2 requirement
and do not require sh_entsize to be a multiple of sh_align.
Now on the updated test merge-entsize.s, all the 3 linkers happily
create .rodata that is not 3-byte aligned.
This has a use case in Linux arch/x86/crypto/sha512-avx2-asm.S
It uses sh_entsize of 640, which is not a power of 2.
See https://github.com/ClangBuiltLinux/linux/issues/417
Reviewers: ruiu, espindola
Reviewed By: ruiu
Subscribers: nickdesaulniers, E5ten, emaste, arichardson, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59478
llvm-svn: 356428
arm-plt-reloc.s arm-thumb-plt-reloc.s: update offset calculations
pack-dyn-relocs-loop.s: this test is very sensitive to exact section
offsets and sizes. If we comment out the following two lines in
SyntheticSections.cpp, we should reproduce `ld.lld: error: thunk
creation not converged` caused by oscillation of the section size.
if (RelocData.size() < OldSize)
RelocData.append(OldSize - RelocData.size(), 0);
Use -z norelro to counteract the layout change (to be more specific,
we have to place .dynamic below .foo so that offset(foo) remains 0x10004)
llvm-svn: 356229
Summary:
Based on Peter Collingbourne's suggestion in D56828.
Before D56828: PT_LOAD(.data PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) .bss)
Old: PT_LOAD(PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) .data .bss)
New: PT_LOAD(PT_GNU_RELRO(.data.rel.ro .bss.rel.ro)) PT_LOAD(.data. .bss)
The new layout reflects the runtime memory mappings.
By having two PT_LOAD segments, we can utilize the NOBITS part of the
first PT_LOAD and save bytes for .bss.rel.ro.
.bss.rel.ro is currently small and only used by copy relocations of
symbols in read-only segments, but it can be used for other purposes in
the future, e.g. if a relro section's statically relocated data is all
zeros, we can move it to .bss.rel.ro.
Reviewers: espindola, ruiu, pcc
Reviewed By: ruiu
Subscribers: nemanjai, jvesely, nhaehnle, javed.absar, kbarton, emaste, arichardson, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D58892
llvm-svn: 356226
We allow an archive file without symbol table as a linker input as a
workaround for a very common error in LTO build. But that logic worked
even for an archive file containing non-bitcode files, which is not
expected. This patch limits that workaround to one that contains only
bitcode files.
Differential Revision: https://reviews.llvm.org/D59373
llvm-svn: 356186
Old: PT_LOAD(.data | PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) | .bss)
New: PT_LOAD(PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) | .data .bss)
The placement of | indicates page alignment caused by PT_GNU_RELRO. The
new layout has simpler rules and saves space for many cases.
Old size: roundup(.data) + roundup(.data.rel.ro)
New size: roundup(.data.rel.ro + .bss.rel.ro) + .data
Other advantages:
* At runtime the 3 memory mappings decrease to 2.
* start(PT_TLS) = start(PT_GNU_RELRO) = start(RW PT_LOAD). This
simplifies binary manipulation tools.
GNU strip before 2.31 discards PT_GNU_RELRO if its
address is not equal to the start of its associated PT_LOAD.
This has been fixed by https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=f2731e0c374e5323ce4cdae2bcc7b7fe22da1a6f
But with this change, we will be compatible with GNU strip before 2.31
* Before, .got.plt (non-relro by default) was placed before .got (relro
by default), which made it impossible to have _GLOBAL_OFFSET_TABLE_
(start of .got.plt on x86-64) equal to the end of .got (R_GOT*_FROM_END)
(https://bugs.llvm.org/show_bug.cgi?id=36555). With the new ordering, we
can improve on this regard if we'd like to.
Reviewers: ruiu, espindola, pcc
Subscribers: emaste, arichardson, llvm-commits, joerg, jdoerfert
Differential Revision: https://reviews.llvm.org/D56828
llvm-svn: 356117
Currently we have -Rpass for filtering the remarks that are displayed as
diagnostics, but when using -fsave-optimization-record, there is no way
to filter the remarks while generating them.
This adds support for filtering remarks by passes using a regex.
Ex: `clang -fsave-optimization-record -foptimization-record-passes=inline`
will only emit the remarks coming from the pass `inline`.
This adds:
* `-fsave-optimization-record` to the driver
* `-opt-record-passes` to cc1
* `-lto-pass-remarks-filter` to the LTOCodeGenerator
* `--opt-remarks-passes` to lld
* `-pass-remarks-filter` to llc, opt, llvm-lto, llvm-lto2
* `-opt-remarks-passes` to gold-plugin
Differential Revision: https://reviews.llvm.org/D59268
Original llvm-svn: 355964
llvm-svn: 355984
This does not appear to be necessary because StringTableSection does not
need to be finalized, which also means that we can remove the call to
finalizeSynthetic on .dynstr.
Differential Revision: https://reviews.llvm.org/D59240
llvm-svn: 355977
Currently we have -Rpass for filtering the remarks that are displayed as
diagnostics, but when using -fsave-optimization-record, there is no way
to filter the remarks while generating them.
This adds support for filtering remarks by passes using a regex.
Ex: `clang -fsave-optimization-record -foptimization-record-passes=inline`
will only emit the remarks coming from the pass `inline`.
This adds:
* `-fsave-optimization-record` to the driver
* `-opt-record-passes` to cc1
* `-lto-pass-remarks-filter` to the LTOCodeGenerator
* `--opt-remarks-passes` to lld
* `-pass-remarks-filter` to llc, opt, llvm-lto, llvm-lto2
* `-opt-remarks-passes` to gold-plugin
Differential Revision: https://reviews.llvm.org/D59268
llvm-svn: 355964
On Darwin targets, llvm-ar creates a Darwin format archive by default,
which ld.lld can't read, so it was printing an unexpected error.
llvm-svn: 355894
This unit test fails if 'zed' appears in your build path, as lld is
echoing out the path of the source file. Change the unit test to
explicitly only match everything after the 'Symbols [' line of the
output, to make sure that this test doesn't inadvertently fail due to
the build path.
llvm-svn: 355748
If the permission does not permit writing and the standard input is a
terminal, rm gives an annoying prompt. chmod u+w to make the output
directory easier to delete.
llvm-svn: 355382
This lets us detect file size overflows when creating a 64-bit binary on
a 32-bit machine.
Differential Revision: https://reviews.llvm.org/D58840
llvm-svn: 355218
This lets us remove the special case from Writer::writeSections(), and also
fixes a bug where .eh_frame_hdr isn't necessarily written in the correct
order if a linker script moves .eh_frame and .eh_frame_hdr into the same
output section.
Differential Revision: https://reviews.llvm.org/D58795
llvm-svn: 355153
This patch removes the precompiled binary from inputs,
replacing it with a YAML. And teaches LLD to report a
section name in case of such error.
Differential revision: https://reviews.llvm.org/D58670
llvm-svn: 354959
Summary:
The gold linker allowed you to output the ELF files after LTO was run. It did
it by using the 'obj-path' option. This replicates that behavior.
Reviewers: espindola, ruiu, MaskRay, pcc
Reviewed By: MaskRay, pcc
Subscribers: grimar, emaste, inglorion, arichardson, steven_wu, dexonsmith, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D56046
llvm-svn: 354917
The linux kernel uses an old flag -p/-no-pipeline-knowledge that is
accepted by bfd and gold but ignored by modern versions of them. The
original option is very old and is pre-ABI, it sometimes comes up in
code-bases that had support for pre ABI toolchains. The Linux kernel uses
it in 3 places in the ARM specific section.
Differential Revision: https://reviews.llvm.org/D58540
llvm-svn: 354769
yaml2obj used to require the Symbol field in relocations, but it hasn't
done so for a couple of years. Another change to yaml2obj will soon land
that will look up the symbol by name or index, if present, and emit an
error if not found. This will mean that an explicit symbol reference
(even to an empty-named symbol) that does not reference a symbol
declared in the yaml will result in an error.
This patch updates tests that would otherwise start emitting errors.
Reviewed by: ruiu, grimar
Differential Revision: https://reviews.llvm.org/D58508
llvm-svn: 354666
Three MIPS-specific sections `.reginfo`, `.MIPS.options`, and `.MIPS.abiflags`
are used by loader to read their contents and setup environment for running
a program. Loader looks up these data in the corresponding segments:
`PT_MIPS_REGINFO`, `PT_MIPS_OPTIONS`, and `PT_MIPS_ABIFLAGS` respectively.
This patch put these sections to separate segments like we do already
for ARM `SHT_ARM_EXIDX` section.
Differential Revision: http://reviews.llvm.org/D58381
llvm-svn: 354468
MIPS R6 code uses the `R_MIPS_PC26_S2` relocation for calls which might
cross boundaries of non-PIC-to-PIC code. We need to create a LA25 thunks
for that case.
llvm-svn: 354312
The patch solves two tasks:
1. MIPS ABI allows to mix regular and microMIPS code and perform
cross-mode jumps. Linker needs to detect such cases and replace
jump/branch instructions by their cross-mode equivalents.
2. Other tools like dunamic linkers need to recognize cases when dynamic
table entries, e_entry field of an ELF header etc point to microMIPS
symbol. Linker should provide such information.
The first task is implemented in the `MIPS<ELFT>::relocateOne()` method.
New routine `fixupCrossModeJump` detects ISA mode change, checks and
replaces an instruction.
The main problem is how to recognize that relocation target is microMIPS
symbol. For absolute and section symbols compiler or assembler set the
less-significant bit of the symbol's value or sum of the symbol's value
and addend. And this bit signals to linker about microMIPS code. For
global symbols compiler cannot do the same trick because other tools like,
for example, disassembler wants to know an actual position of the symbol.
So compiler sets STO_MIPS_MICROMIPS flag in the `st_other` field.
In `MIPS<ELFT>::relocateOne()` method we have a symbol's value only and
cannot access any symbol's attributes. To pass type of the symbol
(regular/microMIPS) to that routine as well as other places where we
write a symbol value as-is (.dynamic section, `Elf_Ehdr::e_entry` field
etc) we set when necessary a less-significant bit in the `getSymVA`
function.
Differential revision: https://reviews.llvm.org/D40147
llvm-svn: 354311
On PowerPC64, it is necessary to keep the LocalEntry bits in st_other,
especially when -r is used. Otherwise, when the resulting object is used
in a posterior linking, LocalEntry info will be unavailable and
functions may be called through the wrong entrypoint.
Patch by Leandro Lupori.
Differential Revision: https://reviews.llvm.org/D56782
llvm-svn: 354184
Previously, we showed the following message for an unknown relocation:
foo.o: unrecognized reloc 256
This patch improves it so that the error message includes a symbol name:
foo.o: unknown relocation (256) against symbol bar
llvm-svn: 354040
Non-GOT non-PLT relocations to non-preemptible ifuncs result in the
creation of a canonical PLT, which now takes the identity of the IFUNC
in the symbol table. This (a) ensures address consistency inside and
outside the module, and (b) fixes a bug where some of these relocations
end up pointing to the resolver.
Fixes (at least) PR40474 and PR40501.
Differential Revision: https://reviews.llvm.org/D57371
llvm-svn: 353981
This fixes a 7.0 -> 8.0 regression when parsing
OUTPUT_FORMAT("elf32-powerpc"); or elf32-bigmips directive in ldscripts
as well as an unknown emulation error when lld is invoked by clang due
to missed elf32ppclinux case.
Patch by vit9696
Differential Revision: https://reviews.llvm.org/D58005
llvm-svn: 353968
Previously, we validated -z options after we process --version or --help flags.
So, if one of these flags is given, we wouldn't show an "unknown -z option"
error. This patch fixes that behavior.
Differential Revision: https://reviews.llvm.org/D55446
llvm-svn: 353967
The printing of branch operands for call instructions was changed to properly
handle negative offsets. Updating the tests to reflect that.
llvm-svn: 353866
gold accepts quoted strings. binutils requires quoted strings for some
kinds of symbols, e.g.:
it accepts quoted symbols with @ in name:
$ echo 'EXTERN("__libc_start_main@@GLIBC_2.2.5")' > a.script
$ g++ a.script
/usr/lib/gcc/x86_64-redhat-linux/4.8.5/../../../../lib64/crt1.o: In function `_start':
(.text+0x20): undefined reference to `main'
collect2: error: ld returned 1 exit status
but rejects them if unquoted:
$ echo 'EXTERN(__libc_start_main@@GLIBC_2.2.5)' > a.script
$ g++ a.script
a.script: file not recognized: File format not recognized
collect2: error: ld returned 1 exit status
To maintain compatibility with existing linker scripts support quoted
strings in lld as well.
Patch by Lucian Adrian Grijincu.
Differential Revision: https://reviews.llvm.org/D57987
llvm-svn: 353756
The code producing error messages relating to missing thin archive
members was missing any testing as far as I could see, so this patch
adds a test for it.
Reviewed by: ruiu
Differential Revision: https://reviews.llvm.org/D57899
llvm-svn: 353508
R_X86_64_PC{8,16} relocations are sign-extended, so when we check
for relocation overflow, we had to use checkInt instead of checkUInt.
I confirmed that GNU linkers create the same output for the test case.
llvm-svn: 353437
This is the same as D57749, but for x64 target.
"ELF Handling For Thread-Local Storage" p41 says (https://www.akkadia.org/drepper/tls.pdf):
R_X86_64_GOTTPOFF relocation is used for IE TLS models.
Hence if linker sees this relocation we should add DF_STATIC_TLS flag.
Differential revision: https://reviews.llvm.org/D57821
llvm-svn: 353378
With the following changes:
1) Compilation fix:
std::atomic<bool> HasStaticTlsModel = false; ->
std::atomic<bool> HasStaticTlsModel{false};
2) Adjusted the comment in code.
Initial commit message:
DF_STATIC_TLS flag indicates that the shared object or executable
contains code using a static thread-local storage scheme.
Patch checks if IE/LE relocations were used to check if the code uses
a static model. If so it sets the DF_STATIC_TLS flag.
Differential revision: https://reviews.llvm.org/D57749
----
Modified : /lld/trunk/ELF/Arch/X86.cpp
Modified : /lld/trunk/ELF/Config.h
Modified : /lld/trunk/ELF/SyntheticSections.cpp
Added : /lld/trunk/test/ELF/Inputs/i386-static-tls-model1.s
Added : /lld/trunk/test/ELF/Inputs/i386-static-tls-model2.s
Added : /lld/trunk/test/ELF/Inputs/i386-static-tls-model3.s
Added : /lld/trunk/test/ELF/Inputs/i386-static-tls-model4.s
Added : /lld/trunk/test/ELF/i386-static-tls-model.s
Modified : /lld/trunk/test/ELF/i386-tls-ie-shared.s
Modified : /lld/trunk/test/ELF/tls-dynamic-i686.s
Modified : /lld/trunk/test/ELF/tls-opt-iele-i686-nopic.s
llvm-svn: 353299
DF_STATIC_TLS flag indicates that the shared object or executable
contains code using a static thread-local storage scheme.
Patch checks if IE/LE relocations were used to check if the code uses
a static model. If so it sets the DF_STATIC_TLS flag.
Differential revision: https://reviews.llvm.org/D57749
llvm-svn: 353293
When a thunk is created to a PLT entry, the call to the thunk is converted
to a non-plt expression with fromPlt(). If the thunk becomes unusable we
retarget the relocation back to its original target and try again. When we
do this we need to make sure that we restore the PLT form of the expression
with toPlt().
This change adds a test case that will fail if toPlt() is removed. We need
to have a call to a preemptible symbol defined within the link unit. If
toPlt() is removed then the relocation to the thunk to the PLT entry for the
preemptible symbol will be retargeted to the preemptible symbol itself
instead of its PLT entry.
Differential Revision: https://reviews.llvm.org/D57743
llvm-svn: 353285
Summary:
R_PPC64_TLSGD and R_PPC64_TLSLD are used as markers on TLS code sequences. After GD-to-IE or GD-to-LE relaxation, the next relocation R_PPC64_REL24 should be skipped to not create a false dependency on __tls_get_addr. When linking statically, the false dependency may cause an "undefined symbol: __tls_get_addr" error.
R_PPC64_GOT_TLSGD16_HA
R_PPC64_GOT_TLSGD16_LO
R_PPC64_TLSGD R_TLSDESC_CALL
R_PPC64_REL24 __tls_get_addr
Reviewers: ruiu, sfertile, syzaara, espindola
Reviewed By: sfertile
Subscribers: emaste, nemanjai, arichardson, kbarton, jsji, llvm-commits, tamur
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D57673
llvm-svn: 353262
Summary:
The following patch adds the "None" line to the section to segment mapping dump.
That line lists the sections that do not belong to any segment.
I realize that this change differs from GNU readelf which does not display the latter information.
I'd rather not add this "feature" under a command line option. I think that might introduce confusion, since users would have to
make an additional decision as to if they want to see all of the section-to-segment map or just a subset of it.
Another option is to only print the "None" line if the `--section-mapping` option is passed; however,
that might also introduce some confusion, because the section-to-segment map would be different between`--program-headers`
and the `--section-mapping` output. While the difference is just the "None" line, it seems that if we choose to display
the segment-to-section mapping, then we should always display the whole map including the sections
that do not belong to segments.
```
Section to Segment mapping:
Segment Sections...
00
01 .interp
02 .interp .note.ABI-tag .gnu.hash
03 .init_array .fini_array .dynamic
04 .dynamic
05 .note.ABI-tag
06 .eh_frame_hdr
07
08 .init_array .fini_array .dynamic .got
None .comment .symtab .strtab .shstrtab <--- THIS LINE
```
Reviewers: grimar, rupprecht, jhenderson, espindola
Reviewed By: rupprecht
Subscribers: khemant, emaste, arichardson, llvm-commits
Differential Revision: https://reviews.llvm.org/D57700
llvm-svn: 353217
Summary:
This follows the ld.bfd/gold behavior.
The error check is useful as it captures a common type of ld.so undefined symbol errors as link-time errors:
// a.cc => a.so (not linked with -z defs)
void f(); // f is undefined
void g() { f(); }
// b.cc => executable with a DT_NEEDED entry on a.so
void g();
int main() { g(); }
// ld.so errors when g() is executed (lazy binding) or when the program is started (-z now)
// symbol lookup error: ... undefined symbol: f
Reviewers: ruiu, grimar, pcc, espindola
Reviewed By: ruiu
Subscribers: llvm-commits, emaste, arichardson
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D57569
llvm-svn: 352943
Summary:
In ld.bfd/gold, --no-allow-shlib-undefined is the default when linking
an executable. This patch implements a check to error on undefined
symbols in a shared object, if all of its DT_NEEDED entries are seen.
Our approach resembles the one used in gold, achieves a good balance to
be useful but not too smart (ld.bfd traces all DSOs and emulates the
behavior of a dynamic linker to catch more cases).
The error is issued based on the symbol table, different from undefined
reference errors issued for relocations. It is most effective when there
are DSOs that were not linked with -z defs (e.g. when static sanitizers
runtime is used).
gold has a comment that some system libraries on GNU/Linux may have
spurious undefined references and thus system libraries should be
excluded (https://sourceware.org/bugzilla/show_bug.cgi?id=6811). The
story may have changed now but we make --allow-shlib-undefined the
default for now. Its interaction with -shared can be discussed in the
future.
Reviewers: ruiu, grimar, pcc, espindola
Reviewed By: ruiu
Subscribers: joerg, emaste, arichardson, llvm-commits
Differential Revision: https://reviews.llvm.org/D57385
llvm-svn: 352826
Summary:
After rLLD344952 ("Add OUTPUT_FORMAT linker script directive support"),
using BFD names such as `elf64-x86-64-freebsd` the `OUTPUT_FORMAT`
linker script command does not work anymore, resulting in errors like:
```
ld: error: /home/dim/src/clang800-import/stand/efi/loader/arch/amd64/ldscript.amd64:2: unknown output format name: elf64-x86-64-freebsd
>>> OUTPUT_FORMAT("elf64-x86-64-freebsd", "elf64-x86-64-freebsd", "elf64-x86-64-freebsd")
>>> ^
```
To fix this, recognize a `-freebsd` suffix in BFD names, and also set
`Configuration::OSABI` to `ELFOSABI_FREEBSD` for those cases.
Add and/or update several test cases to check for the correct results of
these new `OUTPUT_FORMAT` arguments.
Reviewers: ruiu, atanasyan, grimar, hokein, emaste, espindola
Reviewed By: ruiu
Subscribers: nemanjai, javed.absar, arichardson, krytarowski, kristof.beyls, kbarton, llvm-commits
Differential Revision: https://reviews.llvm.org/D57283
llvm-svn: 352606
Previously we were setting it to the GotPlt output section, which is
incorrect on ARM where this section is in .got. In static binaries
this can lead to sh_info being set to -1 (because there is no .got.plt)
which results in various tools rejecting the output file.
Differential Revision: https://reviews.llvm.org/D57274
llvm-svn: 352413
r352366 "[llvm-objdump] - Print LMAs when dumping section headers." changed the format of
llvm-objdump output. We have to update the LLD tests.
llvm-svn: 352372
Summary:
lld discards .gnu.linonce.* sections work around a bug in glibc.
https://sourceware.org/bugzilla/show_bug.cgi?id=20543
Unfortunately, the Linux kernel uses a section named
.gnu.linkonce.this_module to store infomation about kernel modules. The
kernel reads data from this section when loading kernel modules, and
errors if it fails to find this section. The current behavior of lld
discards this section when kernel modules are linked, so kernel modules
linked with lld are unloadable by the linux kernel.
The Linux kernel should use a comdat section instead of .gnu.linkonce.
The minimum version of binutils supported by the kernel supports comdat
sections. The kernel is also not relying on the old linkonce behavior;
it seems to have chosen a name that contains a deprecated GNU feature.
Changing the section name now in the kernel would require all kernel
modules to be recompiled to make use of the new section name. Instead,
rather than discarding .gnu.linkonce.*, let's discard the more specific
section name to continue working around the glibc issue while supporting
linking Linux kernel modules.
Link: https://github.com/ClangBuiltLinux/linux/issues/329
Reviewers: pcc, espindola
Reviewed By: pcc
Subscribers: nathanchance, emaste, arichardson, void, srhines
Differential Revision: https://reviews.llvm.org/D57294
llvm-svn: 352302
Guessing that the slashes used in the scripts SECTION command was causing the
windows related failures in the added test.
Original commit message:
Small code model global variable access on PPC64 has a very limited range of
addressing. The instructions the relocations are used on add an offset in the
range [-0x8000, 0x7FFC] to the toc pointer which points to .got +0x8000, giving
an addressable range of [.got, .got + 0xFFFC]. While user code can be recompiled
with medium and large code models when the binary grows too large for small code
model, there are small code model relocations in the crt files and libgcc.a
which are typically shipped with the distros, and the ABI dictates that linkers
must allow linking of relocatable object files using different code models.
To minimze the chance of relocation overflow, any file that contains a small
code model relocation should have its .toc section placed closer to the .got
then any .toc from a file without small code model relocations.
Differential Revision: https://reviews.llvm.org/D56920
llvm-svn: 352071
This does *not* implement full SHT_GROUP semantic, yet it is a simple step forward:
Sections within a group are still considered valid, but they do not behave as
specified by the standard in case of garbage collection.
Differential Revision: https://reviews.llvm.org/D56437
llvm-svn: 352068
Small code model global variable access on PPC64 has a very limited range of
addressing. The instructions the relocations are used on add an offset in the
range [-0x8000, 0x7FFC] to the toc pointer which points to .got +0x8000, giving
an addressable range of [.got, .got + 0xFFFC]. While user code can be recompiled
with medium and large code models when the binary grows too large for small code
model, there are small code model relocations in the crt files and libgcc.a
which are typically shipped with the distros, and the ABI dictates that linkers
must allow linking of relocatable object files using different code models.
To minimze the chance of relocation overflow, any file that contains a small
code model relocation should have its .toc section placed closer to the .got
then any .toc from a file without small code model relocations.
Differential Revision: https://reviews.llvm.org/D56920
llvm-svn: 351978
Previously, MemoryBlock automatically extends a requested buffer size to a
multiple of page size because (I believe) doing it was thought to be harmless
and with that you could get more memory (on average 2KiB on 4KiB-page systems)
"for free".
That programming interface turned out to be error-prone. If you request N
bytes, you usually expect that a resulting object returns N for `size()`.
That's not the case for MemoryBlock.
Looks like there is only one place where we take the advantage of
allocating more memory than the requested size. So, with this patch, I
simply removed the automatic size expansion feature from MemoryBlock
and do it on the caller side when needed. MemoryBlock now always
returns a buffer whose size is equal to the requested size.
Differential Revision: https://reviews.llvm.org/D56941
llvm-svn: 351916
I was honestly a bit surprised that we didn't do this before. This
patch is to handle "-" as the stdout so that if you pass `-o -` to
lld, for example, it writes an output to stdout instead of file `-`.
I thought that we might want to handle this at a higher level than
FileOutputBuffer, because if we land this patch, we can no longer
create a file whose name is `-` (there's a workaround though; you can
pass `./-` instead of `-`). However, because raw_fd_ostream already
handles `-` as a special file name, I think it's okay and actually
consistent to handle `-` as a special name in FileOutputBuffer.
Differential Revision: https://reviews.llvm.org/D56940
llvm-svn: 351852
As a follow on to D56666 (r351186) there is a case when taking the address
of an ifunc when linking -pie that can generate a spurious can't create
dynamic relocation R_AARCH64_ADR_PREL_PG_HI21 against symbol in readonly
segment. Specifically the case is where the ifunc is in the same
translation unit as the address taker, so given -fpie the compiler knows
the ifunc is defined in the executable so it can use a non-got-generating
relocation.
The error message is due to R_AARCH64_PLT_PAGE_PC not being added to
isRelExpr, its non PLT equivalent R_AARCH64_PAGE_PC is already in
isRelExpr.
Differential Revision: https://reviews.llvm.org/D56724
llvm-svn: 351335
By default LLD will generate position independent Thunks when the --pie or
--shared option is used. Reference to absolute addresses is permitted in
other cases. For some embedded systems position independent thunks are
needed for code that executes before the MMU has been set up. The option
--pic-veneer is used by ld.bfd to force position independent thunks.
The patch adds --pic-veneer as the option is needed for the Linux kernel
on Arm.
fixes pr39886
Differential Revision: https://reviews.llvm.org/D55505
llvm-svn: 351326
If .rela.iplt does not exist, we used to emit a corrupt symbol table
that contains two symbols, .rela_iplt_{start,end}, pointing to a
nonexisting section.
This patch fixes the issue by setting section index 0 to the symbols
if .rel.iplt section does not exist.
Differential Revision: https://reviews.llvm.org/D56623
llvm-svn: 351218
r347650 fixed pr38074 for AArch64 for static linking. It added two new
RelExpr instances R_AARCH64_GOT_PAGE_PC_PLT and R_GOT_PLT. These need to be
added to isStaticLinkTimeConstant so that the address of an ifunc can be
taken when building a shared library.
fixes pr40250
Differential Revision: https://reviews.llvm.org/D56666
llvm-svn: 351186
When the range between the source and target of a V7PILongThunk exceeded an
int32 we would trigger a relocation out of range error for the
R_ARM_MOVT_PREL or R_ARM_THM_MOVT_PREL relocation. This case can happen when
linking the linux kernel as it is loaded above 0xf0000000.
There are two parts to the fix.
- Remove the overflow check for R_ARM_MOVT_PREL or R_ARM_THM_MOVT_PREL. The
ELF for the ARM Architecture document defines these relocations as having no
overflow checking so the check was spurious.
- Use int64_t for the offset calculation, in line with similar thunks so
that PC + (S - P) < 32-bits. This results in less surprising disassembly.
Differential Revision: https://reviews.llvm.org/D56396
llvm-svn: 350836
The section and offset can be very helpful in diagnosing certian errors.
For example on a relocation overflow or misalignment diagnostic:
test.c:(function foo): relocation R_PPC64_ADDR16_DS out of range: ...
The function foo can have many R_PPC64_ADDR16_DS relocations. Adding the offset
and section will identify exactly which relocation is causing the failure.
Differential Revision: https://reviews.llvm.org/D56453
llvm-svn: 350828
In the PPC64 target we map toc-relative relocations, dynamic thread pointer
relative relocations, and got relocations into a corresponding ADDR16 relocation
type for handling in relocateOne. This patch saves the orignal RelType before
mapping to an ADDR16 relocation so that any diagnostic messages will not
mistakenly use the mapped type.
Differential Revision: https://reviews.llvm.org/D56448
llvm-svn: 350827
Patch by Michael Skvortsov!
This change adds a basic support for linking static MSP430 ELF code.
Implemented relocation types are intended to correspond to the BFD.
Differential revision: https://reviews.llvm.org/D56535
llvm-svn: 350819
ARM and AArch64 use TLS variant 1, where the first two words after the
thread pointer are reserved for the TCB, followed by the executable's TLS
segment. Both the thread pointer and the TLS segment are aligned to at
least the TLS segment's alignment.
Android/Bionic historically has not supported ELF TLS, and it has
allocated memory after the thread pointer for several Bionic TLS slots
(currently 9 but soon only 8). At least one of these allocations
(TLS_SLOT_STACK_GUARD == 5) is widespread throughout Android/AArch64
binaries and can't be changed.
To reconcile this disagreement about TLS memory layout, set the minimum
alignment for executable TLS segments to 8 words on ARM/AArch64, which
reserves at least 8 words of memory after the TP (2 for the ABI-specified
TCB and 6 for alignment padding). For simplicity, and because lld doesn't
know when it's targeting Android, increase the alignment regardless of
operating system.
Differential Revision: https://reviews.llvm.org/D53906
llvm-svn: 350681
llvm-readobj currently has a bug (see PR40097) where it prints '@' at
the end of unversioned dynamic symbols. This bug will be fixed in a
separate later commit, but these tests need fixing first.
Reviewed by: ruiu, Higuoxing
Differential Revision: https://reviews.llvm.org/D56388
llvm-svn: 350614
Fixes https://bugs.llvm.org/show_bug.cgi?id=40134
addWrappedSymbols() must be called before addReservedSymbols() because the
latter only defines reserved symbols when they are undefined in the symbol
table. If addWrappedSymbols() is called after, then addUndefined() is called
which may lazily pull in more object files that could reference reserved
symbols.
Differential Revision: https://reviews.llvm.org/D56110
llvm-svn: 350251
Summary:
If a DSO appears more than once with and without --as-needed, ld.bfd and gold consider --no-as-needed to takes precedence over --as-needed. lld didn't and this patch makes it do so.
This makes it a bit away from the position-dependent behavior (how
different occurrences of the same DSO interact) and protects us from
some mysterious runtime errors: if some interceptor libraries add their
own --no-as-needed dependencies (e.g. librt.so), and the user
application specifies -Wl,--as-needed -lrt , the absence of the
DT_NEEDED entry would make dlsym(RTLD_NEXT, "clock_gettime") return NULL
and would break at runtime.
Reviewers: ruiu, espindola
Reviewed By: ruiu
Subscribers: emaste, arichardson, llvm-commits
Differential Revision: https://reviews.llvm.org/D56089
llvm-svn: 350105
There was a bug in LLVM's libDebugInfo where it did not porpagate the
section index through the range query built from low_pc/high_pc. Hard to
test in LLVM, so I'm adding a test here.
llvm-svn: 350011
When parsing CU ranges for gdb-index, handle the error (now propagated
up though the API lld is calling here - previously the error was
printed within the libDebugInfo API, not allowing lld to format or
handle the message at all) - including information about the object and
archive name, as well as failing the link.
llvm-svn: 349979
Summary:
For the 2-bit bloom filter, we currently pick the bits Hash%64 and Hash>>6%64 (Shift2=6), but bits [6:...] are also used to select a word, causing a loss of precision.
In this patch, we choose Shift2=26, with is suggested by Ambrose Feinstein.
Note, Shift2 is computed as maskbitslog2 in bfd/elflink.c and gold/dynobj.cc
It is varying with the number of dynamic symbols but we don't
necessarily copy its rule.
Reviewers: ruiu, espindola
Reviewed By: ruiu
Subscribers: emaste, arichardson, llvm-commits
Differential Revision: https://reviews.llvm.org/D55971
llvm-svn: 349966
Summary:
This is a common error, and because many people don't know what the key
function is, it is sometimes very confusing.
The doc was originally written by Brooks Moses and slightly edited by me.
Reviewers: MaskRay, espindola
Subscribers: emaste, llvm-commits, arichardson
Differential Revision: https://reviews.llvm.org/D55968
llvm-svn: 349941
Summary:
In glibc, libc.so is a linker script with an as-needed dependency on ld-linux-x86-64.so.2
GROUP ( /lib/x86_64-linux-gnu/libc.so.6 /usr/lib/x86_64-linux-gnu/libc_nonshared.a AS_NEEDED ( /lib/x86_64-linux-gnu/ld-linux-x86-64.so.2 ) )
ld-linux-x86-64.so.2 (as-needed) defines some symbols which resolve undefined references in libc.so.6, it will therefore be added as a DT_NEEDED entry, which isn't necessary.
The test case as-needed-not-in-regular.s emulates the libc.so scenario, where ld.bfd and gold don't add DT_NEEDED for a.so
The relevant code in gold/resolve.cc:
// If we have a non-WEAK reference from a regular object to a
// dynamic object, mark the dynamic object as needed.
if (to->is_from_dynobj() && to->in_reg() && !to->is_undef_binding_weak())
to->object()->set_is_needed();
in_reg() appears to do something similar to IsUsedInRegularObj.
This patch makes lld do the similar thing, but moves the check from
addShared to a later stage MarkLive where all symbols are scanned.
Reviewers: ruiu, pcc, espindola
Reviewed By: ruiu
Subscribers: emaste, arichardson, llvm-commits
Differential Revision: https://reviews.llvm.org/D55902
llvm-svn: 349849
When we report an error for symbols defined in the linker script,
we do not report the location properly.
For example:
ld.lld: error: relocation R_AARCH64_CALL26 cannot refer to absolute symbol: aliasto__text
>>> defined in <internal>
>>> referenced by rtoabs.o:(.text+0x4)
This patch fixes that.
Differential revision: https://reviews.llvm.org/D55360
llvm-svn: 349612
Previously, if you pass -static to lld, lld searches for only foo.a
and skips foo.so for -lfoo option. However, it didn't reject .so files
if you directly pass their pathnames via the command line, which is a bug.
Differential Revision: https://reviews.llvm.org/D55845
llvm-svn: 349557
Summary:
Other large sections (e.g. .rela.dyn .dynstr) may push .note.* off the
first page. They won't be available in core files if RLIMIT_CORE is
limited.
This patch gives priority to alloctable SHT_NOTE sections so that they
are assuredly in the first page and will be available in core files.
They are small and contain important information (e.g. .note.gnu.build-id
identifies the origin of the core, .note.tag stores NT_FREEBSD_ABI_TAG).
Note: gold Output_section_order has a similar rule:
// Loadable read-only note sections come next so that the PT_NOTE
// segment is on the first page of the executable.
ORDER_RO_NOTE,
Reviewers: ruiu, pcc, espindola
Subscribers: emaste, arichardson, llvm-commits
Differential Revision: https://reviews.llvm.org/D55800
llvm-svn: 349524
The code here wants the output section offset of the instruction
requiring the errata patch, not the virtual address. Without this
change we can end up placing a patch out of range if the virtual
address of the code section is large enough.
Differential Revision: https://reviews.llvm.org/D55732
llvm-svn: 349386
ARM Architecture v6m is used by the smallest microcontrollers such as the
cortex-m0. It is Thumb only (no Thumb 2) which prevents it from using the
existing Thumb 2 range extension thunks as these use the Thumb 2 movt/movw
instructions. Range extension thunks are not usually needed for
microcontrollers due to the small amount of flash and ram on the device,
however if code is copied from flash into ram then a range extension thunk
is required to call that code.
This change adds support for v6m range extension thunks. The procedure call
standard APCS permits a thunk to corrupt the intra-procedural scratch
register r12 (referred to as ip in the APCS). Most Thumb instructions do
not permit access to high registers (r8 - r15) so the thunks must spill
some low registers (r0 - r7) to perform the control transfer.
Fixes pr39922
Differential Revision: https://reviews.llvm.org/D55555
llvm-svn: 349337
Previously we considered R_ARM_V4BX to be an absolute relocation,
which meant that we rejected it in read-only sections in PIC output
files. Instead, treat it as a hint relocation so that relocation
processing ignores it entirely.
Also fix a problem with the test case where it was never being run
because it has a .yaml extension and we don't run tests with that
extension.
Differential Revision: https://reviews.llvm.org/D55728
llvm-svn: 349216
`--plugin-opt=emit-llvm` is an option for LTO. It makes the linker to
combine all bitcode files and write the result to an output file without
doing codegen. Gold LTO plugin has this option.
This option is being used for some post-link code analysis tools that
have to see a whole program but don't need to see them in the native
machine code.
Differential Revision: https://reviews.llvm.org/D55717
llvm-svn: 349198
In the ABI for the 64-bit Arm architecture the section on weak references
states:
During linking, the symbol value of an undefined weak reference is:
- Zero if the relocation type is absolute
- The address of the place if the relocation type is pc-relative.
The relocations associated with an ADRP are relative so we should resolve
the undefined weak reference to the place instead of 0. This matches GNU
ld.bfd behaviour.
fixes pr34928
Differential Revision: https://reviews.llvm.org/D55599
llvm-svn: 349024
Unlike GNU tar and libarchive bsdtar, NetBSD 'tar -t' output does not
use C-style escapes and instead outputs paths literally. Fix the test
to account both for escaped and literal backslash output.
Differential Revision: https://reviews.llvm.org/D55441
llvm-svn: 348628
This was a missing piece.
We started to print LMAs and information about assignments,
but did not do that for assignments outside of section declarations yet.
The patch implements it.
Differential revision: https://reviews.llvm.org/D45314
llvm-svn: 348468
This is a part of
https://bugs.llvm.org/show_bug.cgi?id=39885
Linker script specification says:
"You can specify a file name to include sections from a particular file. You would
do this if one or more of your files contain special data that needs to be at a
particular location in memory."
LLD did not accept this syntax. The patch implements it.
Differential revision: https://reviews.llvm.org/D55324
llvm-svn: 348463
Patch from Andrew Kelley.
For context, see https://bugs.llvm.org/show_bug.cgi?id=39862
The use case is embedded / OS programming where the kernel wants
access to its own debug info via mapped dwarf info. I have a proof of
concept of this working, using this linker script snippet:
.rodata : ALIGN(4K) {
*(.rodata)
__debug_info_start = .;
KEEP(*(.debug_info))
__debug_info_end = .;
__debug_abbrev_start = .;
KEEP(*(.debug_abbrev))
__debug_abbrev_end = .;
__debug_str_start = .;
KEEP(*(.debug_str))
__debug_str_end = .;
__debug_line_start = .;
KEEP(*(.debug_line))
__debug_line_end =
.;
__debug_ranges_start
= .;
KEEP(*(.debug_ranges))
__debug_ranges_end
= .;
}
Differential revision: https://reviews.llvm.org/D55276
llvm-svn: 348291
When linking the linux kernel on ppc64le
ld.lld -EL -m elf64lppc -Bstatic --orphan-handling=warn --build-id -o
.tmp_vmlinux1 -T ./arch/powerpc/kernel/vmlinux.lds --whole-archive
built-in.a --no-whole-archive --start-group lib/lib.a --end-group
ld.lld: error: discarding .rela.plt section is not allowed
The linker script discards with the following matches
*(.glink .iplt .plt .rela* .comment)
Differential Revision: https://reviews.llvm.org/D54871
llvm-svn: 348258
When linking the linux kernel on ppc64 and ppc
ld.lld: error: unrecognized reloc 11
11 is PPC_REL14 and PPC64_REL14
Differential revision: https://reviews.llvm.org/D54868
llvm-svn: 348255
At least on Linux, if a file size given to FileOutputBuffer is greater
than 2^63, it fails with "Invalid argument" error, which is not a
user-friendly error message. With this patch, lld prints out "output
file too large" instead.
llvm-svn: 348153
Now LLD might build the broken/incomplete .gdb_index when some DWARF v5
sections (like .debug_rnglists and .debug_addr) are used.
Particularly, for the case above, we emit an empty address area.
A test case is provided and patch fixes the issue.
Differential revision: https://reviews.llvm.org/D55109
llvm-svn: 348119
The _GLOBAL_OFFSET_TABLE_ is a linker defined symbol that is placed at
some location relative to the .got, .got.plt or .toc section. On some
targets such as Arm the correctness of some code sequences using a
relocation to _GLOBAL_OFFSET_TABLE_ depend on the value of the symbol
being in the linker defined place. Follow the ld.gold example and give
a multiple symbol definition error. The ld.bfd behaviour is to ignore the
definition in the input object and redefine it, which seems like it could
be more surprising.
fixes pr39587
Differential Revision: https://reviews.llvm.org/D54624
llvm-svn: 347854
Summary:
This reinstates what I originally intended to do in D54361.
It removes the assumption that .debug_gnu_pubnames has increasing CuOffset.
Now we do better than gold here: when .debug_gnu_pubnames contains
multiple sets, gold would think every set has the same CU index as the
first set (incorrect).
Reviewed By: ruiu
Reviewers: ruiu, dblaikie, espindola
Subscribers: emaste, arichardson, arphaman, llvm-commits
Differential Revision: https://reviews.llvm.org/D54483
llvm-svn: 347820
The DT_PLTRELSZ dynamic tag is calculated using the size of the
OutputSection containing the In.RelaPlt InputSection. This will work for the
default no linker script case and the majority of linker scripts.
Unfortunately it doesn't work for some 'almost' sensible linker scripts. It
is permitted by ELF to have a single OutputSection containing both
In.RelaDyn, In.RelaPlt and In.RelaIPlt. It is also permissible for the range
of memory [DT_RELA, DT_RELA + DT_RELASZ) and the range
[DT_JMPREL, DT_JMPREL + DT_JMPRELSZ) to overlap as long as the the latter
range is at the end.
To support this type of linker script use the specific InputSection sizes.
Fixes pr39678
Differential Revision: https://reviews.llvm.org/D54759
llvm-svn: 347736
This is https://bugs.llvm.org/show_bug.cgi?id=38074.
The issue is that when calling a function, LLD generates a
.got entry that points to the IFUNC resolver function when
instead, it should use the PLT entries properly for
handling the IFUNC.
So we should create a got entry that points to PLT entry,
which itself loads the value from
.got.plt, relocated with R_*_IRELATIVE to make things work.
Patch do that.
Differential revision: https://reviews.llvm.org/D54314
llvm-svn: 347650
The changes to the instructions performed by TLS relaxation and the errata
patching are performed with relocations. As these are applied so late the
errata scanning won't see the changes in the section data made by the TLS
relaxation. This can lead to a TLS relaxed sequence being patched when it
doesn't need to be.
The fix checks to see if there is a R_RELAX_TLS_IE_TO_LE instruction at the
same address as the ADRP as this indicates the presence of a relaxation
of a sequence that might get recognised as a patch.
Differential Revision: https://reviews.llvm.org/D54854
llvm-svn: 347649
This is https://bugs.llvm.org//show_bug.cgi?id=38978
Spec says that:
"Objects may be built with the -z nodefaultlib option to
suppress any search of the default locations at runtime.
Use of this option implies that all the dependencies of an
object can be located using its runpaths.
Without this option, which is the most common case, no
matter how you augment the runtime linker's library
search path, its last element is always /usr/lib for 32-bit
objects and /usr/lib/64 for 64-bit objects."
The patch implements this option.
Differential revision: https://reviews.llvm.org/D54577
llvm-svn: 347647
When we are in a error state, script parser will not parse the -defsym
expression and hence will not tokenize it. Then ScriptLexer::Pos will be 0
and LLD will assert and crash here:
MemoryBufferRef ScriptLexer::getCurrentMB() {
assert(!MBs.empty() && Pos > 0); // Bang !
Solution - stop parsing the defsym in a error state. That is consistent
with the regular case (when we parse the linker script).
llvm-svn: 347549
Summary:
This fixes PR39711: -static -z retpolineplt does not produce retpoline PLT header.
-z now is not relevant.
Statically linked executable does not have PLT, but may have IPLT with no header. When -z retpolineplt is specified, however, the repoline PLT header should still be emitted.
I've checked that this fixes the FreeBSD reproduce in PR39711 and a Linux program statically linked against glibc. The programm print "Hi" rather than SIGILL/SIGSEGV.
getPltEntryOffset may look dirty after this patch, but it can be cleaned up later.
Another possible improvement is that when there are non-preemptible IFUNC symbols (rare case, e.g. -Bsymbolic), both In.Plt and In.Iplt can be non-empty and we'll emit the retpoline PLT header twice.
Reviewers: espindola, emaste, chandlerc, ruiu
Reviewed By: emaste
Subscribers: emaste, arichardson, krytarowski, llvm-commits
Differential Revision: https://reviews.llvm.org/D54782
llvm-svn: 347404
When REQUIRES: ARM is used the test is skipped as ARM is not recognized.
Change to REQUIRES: arm so that it is run. This required updating one of the
tests due to changes in expected output.
Differential Revision: https://reviews.llvm.org/D54786
llvm-svn: 347388
Summary:
When --noinhibit-exec is used, ld.bfd/gold emit errors but allow to produce corrupted executable, which is handy for debugging purpose. lld's --noinhibit-exec has a different meaning and changes some errors to warnings. This patch replaces "error" with "errorOrWarn" to exploit that property.
We may revisit this: if we should keep them as errors (as ld.bfd/gold do) but allow to produce a (corrupted) executable.
Reviewers: ruiu, grimar, espindola
Reviewed By: grimar
Subscribers: Timmmm, jhenderson, emaste, arichardson, llvm-commits
Differential Revision: https://reviews.llvm.org/D54651
llvm-svn: 347327
Summary: This patch implementation the handler for ARM_V4BX. This relocation is used by GNU runtime files and other armv4 applications.
Patch by Yin Ma
Reviewers: espindola, MaskRay, ruiu, peter.smith, pcc
Reviewed By: ruiu
Subscribers: yinma, pcc, peter.smith, MaskRay, rovka, efriedma, emaste, javed.absar, arichardson, kristof.beyls, chrib, llvm-commits
Differential Revision: https://reviews.llvm.org/D53444
llvm-svn: 347077
Current value using as a trap instruction (0xefefefef) is not a good choice
for MIPS because it's a valid MIPS instruction `swc3 $15,-4113(ra)`. This
patch replaces 0xefefefef by 0x04170001. For all MIPS ISA revisions before
R6, this value is just invalid instruction. Starting from MIPS R6 it's
a valid instruction `sigrie 1` which signals a Reserved Instruction exception.
mips-traps.s test case is added to test trap encoding. Other test cases
are modified to remove redundant checking.
Differential revision: https://reviews.llvm.org/D54154
llvm-svn: 347029
On PowerPC64, when a function call offset is too large to encode in a call
instruction the address is stored in a table in the data segment. A thunk is
used to load the branch target address from the table relative to the
TOC-pointer and indirectly branch to the callee. When linking position-dependent
code the addresses are stored directly in the table, for position-independent
code the table is allocated and filled in at load time by the dynamic linker.
For position-independent code the branch targets could have gone in the .got.plt
but using the .branch_lt section for both position dependent and position
independent binaries keeps it consitent and helps keep this PPC64 specific logic
seperated from the target-independent code handling the .got.plt.
Differential Revision: https://reviews.llvm.org/D53408
llvm-svn: 346877
The R_AARCH64_ADR_PREL_PG_HI21 relocation type is given the R_PAGE_PC
RelExpr. This can be transformed to R_PLT_PAGE_PC via toPlt().
Unfortunately the resolution is identical to R_PAGE_PC so instead of
getting the address of the PLT entry we get the address of the symbol
which may not be correct in the case of static ifuncs. The fix is to
handle the cases separately and use getPltVA() + A with R_PLT_PAGE_PC.
Differential Revision: https://reviews.llvm.org/D54474
llvm-svn: 346863
gdb-index-multiple-cu-2.s puts the symbol in question to another object file %t1.o, so that its CuIndex is affected by the number of CUs in %t.o
Also change `Kind:` in a comment to `Attributes:` as a follow-up of D54480 and D54481
llvm-svn: 346796
Summary:
Idx passed to readPubNamesAndTypes was an index into Chunks, not an
index into the CU list. This would be incorrect if some .debug_info
section contained more than 1 DW_TAG_compile_unit.
In real world, glibc Scrt1.o is a partial link of start.os abi-note.o init.o and contains 2 CUs in debug builds.
Without this patch, any application linking such Scrt1.o would have invalid .gdb_index
The issue could be demonstrated by:
(gdb) py print(gdb.lookup_global_symbol('main'))
None
Reviewers: espindola, ruiu
Reviewed By: ruiu
Subscribers: Higuoxing, grimar, dblaikie, emaste, aprantl, arichardson, JDevlieghere, arphaman, llvm-commits
Differential Revision: https://reviews.llvm.org/D54361
llvm-svn: 346747
Summary: llvm-readobj/readelf accepts both -s and -S as aliases for --sections. However with GNU readelf only -S means --section, and -s means --symbols. I would like to make llvm-readelf more compatible.
Reviewers: MaskRay, espindola
Reviewed By: MaskRay
Subscribers: emaste, arichardson, steven_wu, dexonsmith, llvm-commits
Differential Revision: https://reviews.llvm.org/D54118
llvm-svn: 346164
Summary:
It is difficult to touch a file with a relative mtime across different OSes as POSIX touch -d is rigid. While we may construct relative timestamps with `date`, POSIX date is inadequate to do so as various OSes' date do not agree on a common format (OpenBSD uses `date -r seconds`, FreeBSD uses `date -v-2M` while GNU accepts `-d '-2 min'`)
Just use python os.utime()
Original description:
The case may randomly fail if we test it with command "
while llvm-lit tools/lld/test/ELF/lto/cache.ll; do true; done". It is because the llvmcache-foo file is younger than llvmcache-349F039B8EB076D412007D82778442BED3148C4E and llvmcache-A8107945C65C2B2BBEE8E61AA604C311D60D58D6. But due to timestamp precision reason their timestamp is the same. Given the same timestamp, the file prune policy is to remove bigger size file first, so mostly foo file is removed for its bigger size. And the files size is under threshold after deleting foo file. That's what test case expect.
However sometimes, the precision is enough to measure that timestamp of llvmcache-349F039B8EB076D412007D82778442BED3148C4E and llvmcache-A8107945C65C2B2BBEE8E61AA604C311D60D58D6 are smaller than foo, so llvmcache-349F039B8EB076D412007D82778442BED3148C4E and llvmcache-A8107945C65C2B2BBEE8E61AA604C311D60D58D6 are deleted first. Since the files size is still above the file size threshold after deleting the 2 files, the foo file is also deleted. And then the test case fails, because it expect only one file should be deleted instead of 3.
The fix is to change the timestamp of llvmcache-foo file to meet the thinLTO prune policy.
The same fix is applied to llvm code at https://reviews.llvm.org/D52452.
Patch by Luo Yuanke.
Reviewers: ruiu, craig.topper, smaslov, Jianping, espindola, LuoYuanke, tejohnson
Reviewed By: tejohnson
Subscribers: sbc100, krytarowski, aheejin, llvm-commits, dexonsmith, steven_wu, arichardson, inglorion, emaste, bjope, rupprecht
Differential Revision: https://reviews.llvm.org/D54039
llvm-svn: 346006
Summary:
The case may randomly fail if we test it with command "
while llvm-lit tools/lld/test/ELF/lto/cache.ll; do true; done". It is because the llvmcache-foo file is younger than llvmcache-349F039B8EB076D412007D82778442BED3148C4E and llvmcache-A8107945C65C2B2BBEE8E61AA604C311D60D58D6. But due to timestamp precision reason their timestamp is the same. Given the same timestamp, the file prune policy is to remove bigger size file first, so mostly foo file is removed for its bigger size. And the files size is under threshold after deleting foo file. That's what test case expect.
However sometimes, the precision is enough to measure that timestamp of llvmcache-349F039B8EB076D412007D82778442BED3148C4E and llvmcache-A8107945C65C2B2BBEE8E61AA604C311D60D58D6 are smaller than foo, so llvmcache-349F039B8EB076D412007D82778442BED3148C4E and llvmcache-A8107945C65C2B2BBEE8E61AA604C311D60D58D6 are deleted first. Since the files size is still above the file size threshold after deleting the 2 files, the foo file is also deleted. And then the test case fails, because it expect only one file should be deleted instead of 3.
The fix is to change the timestamp of llvmcache-foo file to meet the thinLTO prune policy.
The same fix is applied to llvm code at https://reviews.llvm.org/D52452.
Patch by Luo Yuanke.
Reviewers: ruiu, craig.topper, smaslov, Jianping, espindola, LuoYuanke
Subscribers: rupprecht, bjope, emaste, inglorion, arichardson, steven_wu, dexonsmith, llvm-commits
Differential Revision: https://reviews.llvm.org/D53123
llvm-svn: 345977
Summary:
D52830 sets sh_link to .symtab in static link, which breaks executable stripped by GNU strip.
It may also be odd that .rela.plt (SHF_ALLOC) points to .symtab (non-SHF_ALLOC).
Change the logic on pcc's suggestion.
Before:
% clang -fuse-ld=lld -static -xc =(printf 'int main(){}') # or gcc
% strip a.out; ./a.out
unexpected reloc type in static binary[1] 61634 segmentation fault ./a.out
Reviewers: ruiu, grimar, emaste, espindola
Reviewed By: ruiu
Subscribers: pcc, arichardson, llvm-commits
Differential Revision: https://reviews.llvm.org/D53993
llvm-svn: 345899
This is https://bugs.llvm.org/show_bug.cgi?id=39493.
We crashed previously because did not handle /DISCARD/ properly
when -r was used. I think it is uncommon to use scripts with -r, though I see
nothing wrong to handle the /DISCARD/ so that we will not crash at least.
Differential revision: https://reviews.llvm.org/D53864
llvm-svn: 345819
Summary: .rela.plt may only contain R_*_{,I}RELATIVE relocations and not need a symbol table link. bfd/gold fallbacks to sh_link=0 in this case. Without this patch, ld.lld --strip-all caused lld to dereference a null pointer.
Reviewers: ruiu, grimar, espindola
Reviewed By: ruiu
Subscribers: emaste, arichardson, llvm-commits
Differential Revision: https://reviews.llvm.org/D53881
llvm-svn: 345648
Summary: There are too many reasonable cases that would be considered unorderable.
Reviewers: ruiu, espindola, Bigcheese
Reviewed By: ruiu
Subscribers: grimar, emaste, arichardson, llvm-commits
Differential Revision: https://reviews.llvm.org/D53669
llvm-svn: 345322
Out::DebugInfo was used only by GdbIndex class to determine if
we need to create a .gdb_index section, but we can do the same
check without it.
Added a test that this patch doesn't change the existing behavior.
llvm-svn: 345058
Summary:
During upgrading of the FreeBSD source tree with lld 7.0.0, I noticed
that it started complaining about `crt1.o` having an "index past the
end of the symbol table".
Such a symbol table looks approximately like this, viewed with `readelf
-s` (note the `Ndx` field being messed up):
```
Symbol table '.symtab' contains 4 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 00000000 0 NOTYPE LOCAL DEFAULT UND
1: 00000000 0 SECTION LOCAL DEFAULT 1
2: 00000000 0 NOTYPE WEAK HIDDEN RSV[0xffff] __rel_iplt_end
3: 00000000 0 NOTYPE WEAK HIDDEN RSV[0xffff] __rel_iplt_start
```
At first, it seemed that recent ifunc relocation work had caused this:
<https://reviews.freebsd.org/rS339351>, but it turned out that it was
due to incorrect processing of the object files by lld, when using `-r`
(a.k.a. --relocatable).
Bisecting showed that rL324421 ("Convert a use of Config->Static") was
the commit where this new behavior began. Simply reverting it solved
the issue, and the `__rel_iplt` symbols had an index of `UND` again.
Looking at Rafael's commit message, I think he simply missed the
possibility of `--relocatable` being in effect, so I have added an
additional check for it.
I also added a simple regression test case.
Reviewers: grimar, ruiu, emaste, espindola
Reviewed By: ruiu
Subscribers: arichardson, krytarowski, llvm-commits
Differential Revision: https://reviews.llvm.org/D53515
llvm-svn: 345002
emulation.s is testing multiple architectures, which means it needs all
the corresponding backends enabled, which might not be true for all
developers (for example, I don't have PPC or MIPS enabled). Rather than
marking the entire test as unsupported for such developers, split it up
per backend to get better testing granularity.
Differential Revision: https://reviews.llvm.org/D53544
llvm-svn: 344986
Turns out I wasn't actually running this test locally, since I don't
build the PPC and MIPS backends. Whoops.
Perhaps this test should be split up per-architecture?
llvm-svn: 344980
We need this to support 32-bit ARM. Add test cases for emulation
handling for this architecture as well.
Differential Revision: https://reviews.llvm.org/D53539
llvm-svn: 344976
Summary:
Before, superfluous warnings were emitted for the following two cases:
1) When from symbol was in a discarded section.
The profile should be thought of as affiliated to the section.
It makes sense to ignore the profile if the section is discarded.
2) When to symbol was in a shared object.
The object file containing the profile may not know about the to
symbol, which can reside in another object file (useful profile) or a
shared object (not useful as symbols in the shared object are fixed
and unorderable). It makes sense to ignore the profile from the object
file.
Note, the warning when to symbol was undefined was suppressed in
D53044, which is still useful for --symbol-ordering-file=
This patch silences the warnings. The check is actually more relaxed (no
warnings if either From or To is not Defined) for simplicity and I don't
see a compelling reason to warn on more cases.
Reviewers: ruiu, davidxl, espindola, Bigcheese
Reviewed By: ruiu
Subscribers: emaste, arichardson, llvm-commits
Differential Revision: https://reviews.llvm.org/D53470
llvm-svn: 344974
This patch adds a support for OUTPUT_FORMAT linker script directive.
Since I'm not 100% confident with BFD names you can use in the directive
for all architectures, I added only a few in this patch. We can add
other names for other archtiectures later.
We still do not support triple-style OUTPUT_FORMAT directive, namely,
OUTPUT_FORMAT(bfdname, big, little). If you pass -EL (little endian)
or -EB (big endian) to the linker, GNU linkers pick up big or little
as a BFD name, correspondingly, so that you can use a single linker
script for bi-endian processor. I'm not sure if we really need to
support that, so I'll leave it alone for now.
Note that -m takes precedence over OUTPUT_FORAMT, but we always parse
a BFD name given to OUTPUT_FORMAT for error checking. You cannot write
an invalid name in the OUTPUT_FORMAT directive.
Differential Revision: https://reviews.llvm.org/D53495
llvm-svn: 344952
Adjusted the range check on a call instruction from 24 bits signed to
26 bits signed. While the instruction only encodes 24 bits, the target is
assumed to be 4 byte aligned, and the value that is encoded in the instruction
gets shifted left by 2 to form the offset. Also added a check that the offset is
indeed at least 4 byte aligned.
Differential Revision: https://reviews.llvm.org/D53401
llvm-svn: 344747
All the PassBuilder::parse interfaces now return descriptive StringError
instead of a plain bool. It allows to make -passes/aa-pipeline parsing
errors context-specific and thus less confusing.
TODO: ideally we should also make suggestions for misspelled pass names,
but that requires some extensions to PassBuilder.
Reviewed By: philip.pfaffe, chandlerc
Differential Revision: https://reviews.llvm.org/D53246
llvm-svn: 344685
Recommitting https://reviews.llvm.org/rL344544 after fixing undefined behavior
from left-shifting a negative value. Original commit message:
This support is slightly different then the X86_64 implementation in that calls
to __morestack don't need to get rewritten to calls to __moresatck_non_split
when a split-stack caller calls a non-split-stack callee. Instead the size of
the stack frame requested by the caller is adjusted prior to the call to
__morestack. The size the stack-frame will be adjusted by is tune-able through a
new --split-stack-adjust-size option.
llvm-svn: 344622
This reverts commit https://reviews.llvm.org/rL344544, which causes failures on
a undefined behaviour sanitizer bot -->
lld/ELF/Arch/PPC64.cpp:849:35: runtime error: left shift of negative value -1
llvm-svn: 344551
This support is slightly different then the X86_64 implementation in that calls
to __morestack don't need to get rewritten to calls to __moresatck_non_split
when a split-stack caller calls a non-split-stack callee. Instead the size of
the stack frame requested by the caller is adjusted prior to the call to
__morestack. The size the stack-frame will be adjusted by is tune-able through a
new --split-stack-adjust-size option.
Differential Revision: https://reviews.llvm.org/D52099
llvm-svn: 344544
This is https://bugs.llvm.org/show_bug.cgi?id=39289.
Currently both gold and bfd report errors about invalid options values
even with -v/-versions. But LLD does not.
This makes complicated to check the options available when LLD is used.
Patch makes LLD behavior to be consistent with GNU linkers.
Differential revision: https://reviews.llvm.org/D53278
llvm-svn: 344514
Android uses a compressed relocation format, which means the size of the
relocation section isn't predictable based on the number of relocations,
and can vary if the layout changes in any way. To deal with this, the
linker normally runs multiple passes until the layout converges.
The layout should converge if the size of the compressed
relocation section increases monotonically: if the size of an encoded
offset increases by one byte, the larget value which can be encoded is
multiplied by 128, so the representable offsets grow much faster than
the size of the section itself.
The problem here is that there is no code to ensure the size of the
section doesn't decrease. If the size of the relocation section
decreases, the relative offsets can increase due to alignment
restrictions, so that can force the size of the relocation section to
increase again. The end result is an infinite loop; the loop gets cut
off after 10 iterations with the message "thunk creation not
converged".
To avoid this issue, this patch adds padding to the end of the
relocation section if its size would decrease. The extra
padding is harmless because of the way the format is defined:
decoding stops after it reaches the number of relocations specified
in the section's header.
Differential Revision: https://reviews.llvm.org/D53003
llvm-svn: 344300
This is https://bugs.llvm.org/show_bug.cgi?id=37538,
Currently, LLD may set both sh_link and sh_info for
.rela.plt section to zero when we have only .rela.iplt section part used.
ELF spec (https://docs.oracle.com/cd/E19683-01/816-1386/chapter6-94076/index.html)
says that for SHT_REL and SHT_RELA, sh_link references the associated symbol table
and sh_info the "section to which the relocation applies."
When we set the sh_link field, for the regular case we use the .dynsym index.
For .rela.iplt sections, it is unclear what is the associated symbol table,
because R_*_RELATIVE relocations do not use symbol names and we might have no
.dynsym section at all so this patch uses .symtab section index.
Differential revision: https://reviews.llvm.org/D52830
llvm-svn: 344226
Summary:
Add a condition UnresolvedPolicy::Ignore to elf::warnUnorderedSymbol to suppress Sym->isUndefined() warnings from both
1) --symbol-ordering-file=
2) .llvm.call-graph-profile
If --unresolved-symbols=ignore-all is used,
no "undefined symbol" error/warning is emitted. It makes sense to not warn unorderable symbols.
Otherwise,
If an executable is linked, the default policy UnresolvedPolicy::ErrorOrWarn will issue a "undefined symbol" error. The unorderable symbol warning is redundant.
If a shared object is linked, it is possible that only part of object files are used and some symbols are left undefined. The warning is not very necessary.
In particular for .llvm.call-graph-profile, when linking a shared object, a call graph profile may contain undefined symbols. This case generated a warning before but it will be suppressed by this patch.
Reviewers: ruiu, davidxl, espindola
Reviewed By: ruiu
Subscribers: grimar, emaste, arichardson, llvm-commits
Differential Revision: https://reviews.llvm.org/D53044
llvm-svn: 344195
Fangrui Song