[ELF] Move InputFiles global variables (memoryBuffers, objectFiles, etc) into Ctx. NFC

Rename parallelForEachN to just parallelFor

Patch created by running:

rg -l parallelForEachN | xargs sed -i '' -c 's/parallelForEachN/parallelFor/'

No behavior change.

Differential Revision: ht

Rename parallelForEachN to just parallelFor

Patch created by running:

rg -l parallelForEachN | xargs sed -i '' -c 's/parallelForEachN/parallelFor/'

No behavior change.

Differential Revision: https://reviews.llvm.org/D128140

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[ELF] Don't use multiple inheritance for OutputSection. NFC

Add an OutputDesc class inheriting from SectionCommand. An OutputDesc wraps an
OutputSection. This change allows InputSection::getParent t

[ELF] Don't use multiple inheritance for OutputSection. NFC

Add an OutputDesc class inheriting from SectionCommand. An OutputDesc wraps an
OutputSection. This change allows InputSection::getParent to be inlined.

Differential Revision: https://reviews.llvm.org/D120650

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[ELF] Don't rely on Symbols.h's transitive inclusion of InputFiles.h. NFC

[ELF] Replace uncompressed InputSectionBase::data() with rawData. NFC

In many call sites we know uncompression cannot happen (non-SHF_ALLOC, or the
data (even if compressed) must have been uncompres

[ELF] Replace uncompressed InputSectionBase::data() with rawData. NFC

In many call sites we know uncompression cannot happen (non-SHF_ALLOC, or the
data (even if compressed) must have been uncompressed by a previous pass).
Prefer rawData in these cases. data() increases code size and prevents
optimization on rawData.

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[ELF] Clean up headers. NFC

[ELF] Change vector<InputSection *> to SmallVector. NFC

My x86-64 lld executable is 8KiB smaller.

[ELF] Simplify Symbol::includeInDynsym

[ELF] Avoid referencing SectionBase::repl after ICF

It is fairly easy to forget SectionBase::repl after ICF.
Let ICF rewrite a Defined symbol's `section` field to avoid references to
SectionBase::re

[ELF] Avoid referencing SectionBase::repl after ICF

It is fairly easy to forget SectionBase::repl after ICF.
Let ICF rewrite a Defined symbol's `section` field to avoid references to
SectionBase::repl in subsequent passes. This slightly improves the --icf=none
performance due to less indirection (maybe for --icf={safe,all} as well if most
symbols are Defined).

With this change, there is only one reference to `repl` (--gdb-index D89751).
We can undo f4fb5fd7523f8e3c3b3966d43c0a28457b59d1d8 (`Move Repl to SectionBase.`)
but move `repl` to `InputSection` instead.

Reviewed By: ikudrin

Differential Revision: https://reviews.llvm.org/D116093

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[ELF] Rename BaseCommand to SectionCommand. NFC

BaseCommand was picked when PHDRS/INSERT/etc were not implemented. Rename it to
SectionCommand to match `sectionCommands` and make it clear that the c

[ELF] Rename BaseCommand to SectionCommand. NFC

BaseCommand was picked when PHDRS/INSERT/etc were not implemented. Rename it to
SectionCommand to match `sectionCommands` and make it clear that the commands
are used in SECTIONS (except a special case for SymbolAssignment).

Also, improve naming of some BaseCommand variables (base -> cmd).

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[ELF] Rename OutputSection::sectionCommands to commands. NFC

This partially reverts r315409: the description applies to LinkerScript, but not
to OutputSection.

The name "sectionCommands" is used in

[ELF] Rename OutputSection::sectionCommands to commands. NFC

This partially reverts r315409: the description applies to LinkerScript, but not
to OutputSection.

The name "sectionCommands" is used in both LinkerScript::sectionCommands and
OutputSection::sectionCommands, which may lead to confusion.
"commands" in OutputSection has no ambiguity because there are no other types
of commands.

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[ELF] Replace InputBaseSection::{areRelocsRela,firstRelocation,numRelocation} with relSecIdx

For `InputSection` `.foo`, its `InputBaseSection::{areRelocsRela,firstRelocation,numRelocation}` basicall

[ELF] Replace InputBaseSection::{areRelocsRela,firstRelocation,numRelocation} with relSecIdx

For `InputSection` `.foo`, its `InputBaseSection::{areRelocsRela,firstRelocation,numRelocation}` basically
encode the information of `.rel[a].foo`. However, one uint32_t (the relocation section index)
suffices. See the implementation of `relsOrRelas`.

This change decreases sizeof(InputSection) from 184 to 176 on 64-bit Linux.

The maximum resident set size linking a large application (1.2G output) decreases by 0.39%.

Differential Revision: https://reviews.llvm.org/D112513

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[LLD][ELF] Improve ICF for relocations to ineligible sections via "aliases"

ICF was not able to merge equivalent sections because of relocations to
sections ineligible for ICF that use alternative s

[LLD][ELF] Improve ICF for relocations to ineligible sections via "aliases"

ICF was not able to merge equivalent sections because of relocations to
sections ineligible for ICF that use alternative symbols, e.g. symbol
aliases or section relative relocations.

Merging in this scenario has been enabled by giving the sections that
are ineligible for ICF a unique ID, i.e. an equivalence class of their
own. This approach also provides another benefit as it improves the
hashing that is used to perform the initial equivalance grouping for
ICF. This is because the ICF ineligible sections can now contribute a
unique value towards the hashes instead of the same value of zero. This
has been seen to reduce link time with ICF by ~68% for objects compiled
with -fprofile-instr-generate.

In order to facilitate this use of a unique ID, the existing
inconsistent approach to the setting of the InputSection eqClass in ICF
has been changed so that there is a clear distinction between the
eqClass values of ICF eligible sections and those of the ineligible
sections that have a unique ID. This inconsistency could have caused
incorrect equivalence class equality in the past, although it appears
that no issues were encountered in actual use.

Differential Revision: https://reviews.llvm.org/D88830

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[ELF]: --icf: don't fold sections referencing sections with LCDA after D84610

[ELF] --icf: don't fold text sections with LSDA

Fix PR36272 and PR46835

A .eh_frame FDE references a text section and (optionally) a LSDA (in
.gcc_except_table). Even if two text sections have ide

[ELF] --icf: don't fold text sections with LSDA

Fix PR36272 and PR46835

A .eh_frame FDE references a text section and (optionally) a LSDA (in
.gcc_except_table). Even if two text sections have identical content and
relocations (e.g. a() and b()), we cannot fold them if their LSDA are different.

```
void foo();
void a() {
try { foo(); } catch (int) { }
}
void b() {
try { foo(); } catch (float) { }
}
```

Scan .eh_frame pieces with LSDA and disallow referenced text sections to be
folded. If two .gcc_except_table have identical semantics (usually identical
content with PC-relative encoding), we will lose folding opportunity.
For ClickHouse (an exception-heavy application), this can reduce --icf=all efficiency
from 9% to 5%. There may be some percentage we can reclaim without affecting
correctness, if we analyze .eh_frame and .gcc_except_table sections.

gold 2.24 implemented a more complex fix (resolution to
https://sourceware.org/bugzilla/show_bug.cgi?id=21066) which combines the
checksum of .eh_frame CIE/FDE pieces.

Reviewed By: grimar

Differential Revision: https://reviews.llvm.org/D84610

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[ELF] Use namespace qualifiers (lld:: or elf::) instead of `namespace lld { namespace elf {`

Similar to D74882. This reverts much code from commit
bd8cfe65f5fee4ad573adc2172359c9552e8cdc0 (D68323) a

[ELF] Use namespace qualifiers (lld:: or elf::) instead of `namespace lld { namespace elf {`

Similar to D74882. This reverts much code from commit
bd8cfe65f5fee4ad573adc2172359c9552e8cdc0 (D68323) and fixes some
problems before D68323.

Sorry for the churn but D68323 was a mistake. Namespace qualifiers avoid
bugs where the definition does not match the declaration from the
header. See
https://llvm.org/docs/CodingStandards.html#use-namespace-qualifiers-to-implement-previously-declared-functions (D74515)

Differential Revision: https://reviews.llvm.org/D79982

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[Support] Move LLD's parallel algorithm wrappers to support

Essentially takes the lld/Common/Threads.h wrappers and moves them to
the llvm/Support/Paralle.h algorithm header.

The changes are:
- Rem

[Support] Move LLD's parallel algorithm wrappers to support

Essentially takes the lld/Common/Threads.h wrappers and moves them to
the llvm/Support/Paralle.h algorithm header.

The changes are:
- Remove policy parameter, since all clients use `par`.
- Rename the methods to `parallelSort` etc to match LLVM style, since
they are no longer C++17 pstl compatible.
- Move algorithms from llvm::parallel:: to llvm::, since they have
"parallel" in the name and are no longer overloads of the regular
algorithms.
- Add range overloads
- Use the sequential algorithm directly when 1 thread is requested
(skips task grouping)
- Fix the index type of parallelForEachN to size_t. Nobody in LLVM was
using any other parameter, and it made overload resolution hard for
for_each_n(par, 0, foo.size(), ...) because 0 is int, not size_t.

Remove Threads.h and update LLD for that.

This is a prerequisite for parallel public symbol processing in the PDB
library, which is in LLVM.

Reviewed By: MaskRay, aganea

Differential Revision: https://reviews.llvm.org/D79390

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[lld][COFF][ELF][WebAssembly] Replace --[no-]threads /threads[:no] with --threads={1,2,...} /threads:{1,2,...}

--no-threads is a name copied from gold.
gold has --no-thread, --thread-count and sever

[lld][COFF][ELF][WebAssembly] Replace --[no-]threads /threads[:no] with --threads={1,2,...} /threads:{1,2,...}

--no-threads is a name copied from gold.
gold has --no-thread, --thread-count and several other --thread-count-*.

There are needs to customize the number of threads (running several lld
processes concurrently or customizing the number of LTO threads).
Having a single --threads=N is a straightforward replacement of gold's
--no-threads + --thread-count.

--no-threads is used rarely. So just delete --no-threads instead of
keeping it for compatibility for a while.

If --threads= is specified (ELF,wasm; COFF /threads: is similar),
--thinlto-jobs= defaults to --threads=,
otherwise all available hardware threads are used.

There is currently no way to override a --threads={1,2,...}. It is still
a debate whether we should use --threads=all.

Reviewed By: rnk, aganea

Differential Revision: https://reviews.llvm.org/D76885

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[LLD][ELF] Add time-trace to ELF LLD

This adds some of LLD specific scopes and picks up optimisation scopes
via LTO/ThinLTO. Makes use of TimeProfiler multi-thread support added in
77e6bb3c.

Differ

[LLD][ELF] Add time-trace to ELF LLD

This adds some of LLD specific scopes and picks up optimisation scopes
via LTO/ThinLTO. Makes use of TimeProfiler multi-thread support added in
77e6bb3c.

Differential Revision: https://reviews.llvm.org/D71060

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[lld] Fix trivial typos in comments

Reviewed By: ruiu, MaskRay

Differential Revision: https://reviews.llvm.org/D72196

Revert an accidental commit af5ca40b47b3e85c3add81ccdc0b787c4bc355ae

temporary

[ELF] Move a computeIsPreemptible() pass into ICF. NFC

Address post-commit review for D71163.

Reviewed By: ruiu

Differential Revision: https://reviews.llvm.org/D71326

[ELF] --icf: do not fold preemptible symbols

Fixes PR44124.

A preemptible symbol may refer to a different definition at runtime.
When comparing a pair of relocations, if they refer to different
sym

[ELF] --icf: do not fold preemptible symbols

Fixes PR44124.

A preemptible symbol may refer to a different definition at runtime.
When comparing a pair of relocations, if they refer to different
symbols, and either symbol is preemptible, the two containing sections
should be considered different.

gold has a similar rule https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commit;h=ce97fa81e0c46d216b80b143ad8c02fff6906fef

Reviewed By: grimar

Differential Revision: https://reviews.llvm.org/D71163

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[ELF] Wrap things in `namespace lld { namespace elf {`, NFC

This makes it clear `ELF/**/*.cpp` files define things in the `lld::elf`
namespace and simplifies `elf::foo` to `foo`.

Reviewed By: atana

[ELF] Wrap things in `namespace lld { namespace elf {`, NFC

This makes it clear `ELF/**/*.cpp` files define things in the `lld::elf`
namespace and simplifies `elf::foo` to `foo`.

Reviewed By: atanasyan, grimar, ruiu

Differential Revision: https://reviews.llvm.org/D68323

llvm-svn: 373885

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