If a copy related symbol (say `copy`) is referenced in two .o
files, this change removes a duplicated line from the -Map output:
```
202470 202470 1 1 .bss.rel.ro
202470 202470 1 1 <internal>:(.bss.rel.ro)
202470 202470 1 1 copy
removed 202470 202470 1 1 copy
```
Differential Revision: https://reviews.llvm.org/D115697
needsPltAddr is equivalent to `needsCopy && isFunc`. In many places, it is
equivalent to `needsCopy` because the non-STT_FUNC cases are ruled out.
Reviewed By: ikudrin, peter.smith
Differential Revision: https://reviews.llvm.org/D115603
(Fixed an issue about GOT on a copy relocated alias.)
The idea is to make scanRelocations mark some actions are needed (GOT/PLT/etc)
and postpone the real work to postScanRelocations. It gives some flexibility:
* Make it feasible to support .plt.got (PR32938): we need to know whether GLOB_DAT and JUMP_SLOT are both needed.
* Make non-preemptible IFUNC handling slightly cleaner: avoid setting/clearing sym.gotInIgot
* -z nocopyrel: report all copy relocation places for one symbol
* Make GOT deduplication feasible
* Make parallel relocation scanning feasible (if we can avoid all stateful operations and make Symbol attributes atomic), but parallelism may not be the appealing choice
Since this patch moves a large chunk of code out of ELFT templates. My x86-64
executable is actually a few hundred bytes smaller.
For ppc32-ifunc-nonpreemptible-pic.s: I remove absolute relocation references to non-preemptible ifunc
because absolute relocation references are incorrect in -fpie mode.
Reviewed By: peter.smith, ikudrin
Differential Revision: https://reviews.llvm.org/D114783
This reverts commit fc33861d48.
`replaceWithDefined` should copy needsGot, otherwise an alias for a copy
relocated symbol may not have GOT entry if its needsGot was originally true.
lld only needs DIContext.h which it gets through Symbolize.h -> SymbolizableModule.h -> DIContext.h. This replaces it with a direct include of DIContext.h to avoid any confusion and pulling in unnecessary headers.
Reviewed By: phosek
Differential Revision: https://reviews.llvm.org/D115659
The idea is to make scanRelocations mark some actions are needed (GOT/PLT/etc)
and postpone the real work to postScanRelocations. It gives some flexibility:
* Make it feasible to support .plt.got (PR32938): we need to know whether GLOB_DAT and JUMP_SLOT are both needed.
* Make non-preemptible IFUNC handling slightly cleaner: avoid setting/clearing sym.gotInIgot
* -z nocopyrel: report all copy relocation places for one symbol
* Make parallel relocation scanning possible (if we can avoid all stateful operations and make Symbol attributes atomic), but parallelism may not be the appealing choice
* Make GOT deduplication feasible
Since this patch moves a large chunk of code out of ELFT templates. My x86-64
executable is actually a few hundred bytes smaller.
For ppc32-ifunc-nonpreemptible-pic.s: I remove absolute relocation references to non-preemptible ifunc
because absolute relocation references are incorrect in -fpie mode.
Reviewed By: peter.smith, ikudrin
Differential Revision: https://reviews.llvm.org/D114783
An unstable sort suffices. In a large link (11.06s), this decreases .rela.dyn
writeTo time from 1.52s to 0.81s, resulting in 6% total time speedup (the
benefit will greatly dilute if --pack-dyn-relocs=relr becomes prevailing).
Encoding the dynamic relocations then sorting raw Elf_Rel/Elf_Rela doesn't seem
to improve much (doing that would require code duplicate because of
Elf_Rel/Elf_Rela plus unfortunate mips64le), so don't do that.
1. After D113241, we have the section address easily accessible and no
longer need to iterate across the LC_SEGMENT commands to emit
LC_DATA_IN_CODE.
2. There's no need to store a pointer to the data in code entries during
the parse step; we can just look it up as part of the output step.
Reviewed By: #lld-macho, thakis
Differential Revision: https://reviews.llvm.org/D115556
... only whether they have more than zero. This simplifies the code slightly.
I've also moved the field into the ConcatInputSection subclass since it doesn't
actually get used by the other InputSections.
Reviewed By: #lld-macho, oontvoo
Differential Revision: https://reviews.llvm.org/D115539
This fixes an issue introduced in D101996.
A weak reference in a shared library could be incorrectly reported if
there is another library that has a strong reference to the same symbol.
Differential Revision: https://reviews.llvm.org/D115041
Enable the pdbpagesize flag to allow linking of PDB files > 4GB.
Also includes a couple small fixes to change to uint64_t to support the
larger file sizes. I updated the max file size check in MSFBuilder.cpp
to take into account the page size.
Differential Revision: https://reviews.llvm.org/D115051
We were fetching archive symbols too eagerly, bloating binary size as well as
just screwing up binaries that expected to look up certain symbols only at
runtime.
Reviewed By: #lld-macho, oontvoo
Differential Revision: https://reviews.llvm.org/D115092
This patch proposes to move emission of global variables, types,
imported entities, etc from DwarfDebug::beginModule() to DwarfDebug::endModule().
Effectively, this changes nothing but the order of debug entities which
will be as follows:
* subprograms (including related context, local variables/labels,
local imported entities; related types can be created as a part of
the emission of local entities of an abstract subprogram);
* global variables (including related context and types);
* retained types and enums;
* non-local-scoped imported entities;
* basic types;
* other types left (as a part of local variables attributes emission).
Note that the order of emitted compile units may also be changed as now we emit
units that contain subprograms first and then all other non-empty units.
The motivation behind this change is the following:
(1) DwarfDebug::beginModule() is run at the very beginning of backend's pipeline,
from this time IR can be significantly changed by target-specific passes.
If it happens for debug metadata of global entities, those changes will not
be reflected in the emitted DWARF.
(2) imported subprogram names should refer to an abstract subprogram if it exists,
but it isn't known in DwarfDebug::beginModule() (it's possible to make some
guesses based on location info, but it's not quite reliable);
(3) aforementioned entities if they are scoped within a bracketed block
(subject of D113741) couldn't be emitted in DwarfDebug::beginModule()
(they need parent emitted first). Another problem is if to try to gather
some information about local entities and defer their emission
(till subprogram's processing or DwarfDebug::endModule()) all the gathered
details might be irrelevant / invalid by the time the entities are being
emitted (because of (1)).
Reviewed By: dblaikie
Differential Revision: https://reviews.llvm.org/D114705
Mach-O LLD uses the buffer identifier of the memory buffer backing an object
file to generate stabs which are used by `dsymutil` to find the object file for
dSYM generation.
When using thinLTO, these buffers are provided by the cache which initially
saves them to disk as temporary files beginning with "Thin-" but renames them
to persistent files beginning with "llvmcache-" before the buffer is provided
to the cache user.
However, the buffer is created before the file is renamed and is given the temp
file's name as an identifier. This causes the generated stabs to point to
nonexistent files.
This change names the buffer with the eventual persistent filename. I think
this is safe because failing to rename the temp file is a fatal error.
Differential Revision: https://reviews.llvm.org/D115055
This patch proposes to move emission of global variables, types,
imported entities, etc from DwarfDebug::beginModule() to DwarfDebug::endModule().
Effectively, this changes nothing but the order of debug entities which
will be as follows:
* subprograms (including related context, local variables/labels,
local imported entities; related types can be created as a part of
the emission of local entities of an abstract subprogram);
* global variables (including related context and types);
* retained types and enums;
* non-local-scoped imported entities;
* basic types;
* other types left (as a part of local variables attributes emission).
Note that the order of emitted compile units may also be changed as now we emit
units that contain subprograms first and then all other non-empty units.
The motivation behind this change is the following:
(1) DwarfDebug::beginModule() is run at the very beginning of backend's pipeline,
from this time IR can be significantly changed by target-specific passes.
If it happens for debug metadata of global entities, those changes will not
be reflected in the emitted DWARF.
(2) imported subprogram names should refer to an abstract subprogram if it exists,
but it isn't known in DwarfDebug::beginModule() (it's possible to make some
guesses based on location info, but it's not quite reliable);
(3) aforementioned entities if they are scoped within a bracketed block
(subject of D113741) couldn't be emitted in DwarfDebug::beginModule()
(they need parent emitted first). Another problem is if to try to gather
some information about local entities and defer their emission
(till subprogram's processing or DwarfDebug::endModule()) all the gathered
details might be irrelevant / invalid by the time the entities are being
emitted (because of (1)).
Reviewed By: dblaikie
Differential Revision: https://reviews.llvm.org/D114705
PLT usage needs the first 12 bytes of the .got section. We need to keep .got and
DT_GOT_PPC even if .got/_GLOBAL_OFFSET_TABLE_ are not referenced (large PIC code
may only reference .got2), which is the case in OpenBSD's ld.so, leading
to a misleading error, "unsupported insecure BSS PLT object".
Fix this by adding R_PPC32_PLTREL to the list of hasGotOffRel.
Reviewed By: MaskRay
Differential Revision: https://reviews.llvm.org/D114982
During the llvm round table it was generally agreed that the newer macho
lld implementation is feature complete enough to replace the old
implementation entirely. This will reduce confusion for new users who
aren't aware of the history.
Differential Revision: https://reviews.llvm.org/D114842
This is very similar to https://reviews.llvm.org/D103557 but applies to
symbols which are undefined at link time rather than compile time.
We already have code that handles symbols which were defined at link
time but dead stripped by `--gc-sections` (See
`test/wasm/debug-removed-fn.ll`). In that case the symbols are not live
(!isLive()). However, we can also have live symbols (which are
references by the program) but which are undefined at link time and are
imported by the linker.
In the test case here the symbol `undef` is used but is not defined
in the program but is imported by the linker due to the
`--import-undefined` flag.
Fixes: https://github.com/emscripten-core/emscripten/issues/15528
Differential Revision: https://reviews.llvm.org/D114921
When a comdat symbol is defined in both bitcode and regular object
files, which are contained in the same archive, the linker could lose
the flag that the symbol is used in the regular object file and allow
LTO to internalize it, which led to "error: undefined symbol".
The issue was introduced in D79300.
Differential Revision: https://reviews.llvm.org/D114801
This reverts the PPC64PCRelLongBranchThunk part from D86706.
PPC64PCRelLongBranchThunk is the same as PPC64R12SetupStub.
Use `__gep_setup_` instead of `__long_branch_pcrel_` for the stub symbol name
as it more closely indicates the operation.
(Note: GNU ld uses `*.long_branch.*` and `*.plt_branch.*`).
Reviewed By: NeHuang, nemanjai
Differential Revision: https://reviews.llvm.org/D114656
There is a trend of having more optional options (usually security
hardening related) like -z cet-report=, -z bti-report=, -z force-bti.
If ld.lld 14.0.0 uses a warning, in 15/16/17/... timeframe when people
add new options to software, they can worry less about linker errors on ld.lld 14.0.0.
In some cases `-z foo` does essential work where a silent ignore can be
problematic, but the user has received a warning. From my observation, the
doing-essential-work `-z foo` is much fewer than the converse. In addition,
the user who cares can use `--fatal-warnings` (Note: GNU ld doesn't upgrade warnings to errors).
It is unclear whether we need something like `clang -Wunknown-warning-option`.
If we ever run into unfortunate transition like `-z start-stop-gc`, the
affected software (e.g. ldc is a compiler which passes linker options to the underlying ld)
can blindly add the `-z` option, without worrying it may cause a linker error to LLD 14.0.0.
Reviewed By: jrtc27, peter.smith
Differential Revision: https://reviews.llvm.org/D114748
Make one change: when the OutputSection is nullptr (due to /DISCARD/ or garbage
collected BssSection (replaceCommonSymbols)), discard the SyntheticSection as well.
I attempted to remove it 1 or 2 year ago but kept it just to have a good
diagnostic in case the output section is nullptr (should be impossible).
It is long enough that we haven't seen such a case.
Fix r285764: there is no guarantee that Out::first is placed before other
static data members of `struct Out`. After `bufferStart` was introduced, this
out-of-bounds write is destined in many compilers. It is likely benign, though.
And move `Out::elfHeader->size` assignment beside `Out::elfHeader->sectionIndex`
Fangrui Song