[ELF] Move --print-archive-stats= and --why-extract= beside --warn-backrefs report

So that early errors don't suppress their output.

[ELF] --cref: If -Map is specified, print to the map file

PR48282: This behavior matches GNU ld and gold.

Reviewed By: markj

Differential Revision: https://reviews.llvm.org/D114663

[ELF] Add --why-extract= to query why archive members/lazy object files are extracted

Similar to D69607 but for archive member extraction unrelated to GC. This patch adds --why-extract=.

Prior art:

[ELF] Add --why-extract= to query why archive members/lazy object files are extracted

Similar to D69607 but for archive member extraction unrelated to GC. This patch adds --why-extract=.

Prior art:

GNU ld -M prints
```
Archive member included to satisfy reference by file (symbol)

a.a(a.o) main.o (a)
b.a(b.o) (b())
```

-M is mainly for input section/symbol assignment <-> output section mapping
(often huge output) and the information may appear ad-hoc.

Apple ld64
```
__Z1bv forced load of b.a(b.o)
_a forced load of a.a(a.o)
```

It doesn't say the reference file.

Arm's proprietary linker
```
Selecting member vsnprintf.o(c_wfu.l) to define vsnprintf.
...
Loading member vsnprintf.o from c_wfu.l.
definition: vsnprintf
reference : _printf_a
```

---

--why-extract= gives the user the full data (which is much shorter than GNU ld
-Map). It is easy to track a chain of references to one archive member with a
one-liner, e.g.

```
% ld.lld main.o a_b.a b_c.a c.a -o /dev/null --why-extract=- | tee stdout
reference extracted symbol
main.o a_b.a(a_b.o) a
a_b.a(a_b.o) b_c.a(b_c.o) b()
b_c.a(b_c.o) c.a(c.o) c()

% ruby -ane 'BEGIN{p={}}; p[$F[1]]=[$F[0],$F[2]] if $.>1; END{x="c.a(c.o)"; while y=p[x]; puts "#{y[0]} extracts #{x} to resolve #{y[1]}"; x=y[0] end}' stdout
b_c.a(b_c.o) extracts c.a(c.o) to resolve c()
a_b.a(a_b.o) extracts b_c.a(b_c.o) to resolve b()
main.o extracts a_b.a(a_b.o) to resolve a
```

Archive member extraction happens before --gc-sections, so this may not be a live path
under --gc-sections, but I think it is a good approximation in practice.

* Specifying a file avoids output interleaving with --verbose.
* Required `=` prevents accidental overwrite of an input if the user forgets `=`. (Most of compiler drivers' long options accept `=` but not ` `)

Differential Revision: https://reviews.llvm.org/D109572

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[ELF] Add --print-archive-stats=

gold has an option --print-symbol-counts= which prints:

// For each archive
archive $archive $members $fetched_members
// For each object file
symbols $obje

[ELF] Add --print-archive-stats=

gold has an option --print-symbol-counts= which prints:

// For each archive
archive $archive $members $fetched_members
// For each object file
symbols $object $defined_symbols $used_defined_symbols

In most cases, `$defined_symbols = $used_defined_symbols` unless weak
symbols are present. Strangely `$used_defined_symbols` includes symbols defined relative to --gc-sections discarded sections.
The `symbols` lines do not appear to be useful.

`archive` lines are useful: `$fetched_members=0` lines correspond to
unused archives. The information can be used to trim dependencies.

This patch implements --print-archive-stats= which prints the number of
members and the number of fetched members for each archive.

Reviewed By: grimar

Differential Revision: https://reviews.llvm.org/D78983

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Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the ne

Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636

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Implement --cref.

This is an option to print out a table of symbols and filenames.
The output format of this option is the same as GNU, so that it can be
processed by the same scripts as before afte

Implement --cref.

This is an option to print out a table of symbols and filenames.
The output format of this option is the same as GNU, so that it can be
processed by the same scripts as before after migrating from GNU to lld.

This option is mildly useful; we can live without it. But it is pretty
convenient sometimes, and it can be implemented in 50 lines of code, so
I think lld should support this option.

Differential Revision: https://reviews.llvm.org/D44336

llvm-svn: 327565

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Pass symbol attributes instead of ElfSym to Shared symbol ctor.

This change allows us to use less templates for Shared symbol and
the functions that deals with shared symbols.

llvm-svn: 316841

Merge OutputSectionCommand and OutputSection.

This is a bit of a hack, but it is *so* convenient.

Now that we create synthetic linker scripts when none is provided, we
always have to handle paired

Merge OutputSectionCommand and OutputSection.

This is a bit of a hack, but it is *so* convenient.

Now that we create synthetic linker scripts when none is provided, we
always have to handle paired OutputSection and OutputsectionCommand and
keep a mapping from one to the other.

This patch simplifies things by merging them and creating what used to
be OutputSectionCommands really early.

llvm-svn: 309311

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[ELF] - Apply clang-format. NFC.

llvm-svn: 308297

Keep a list of all OutputSectionCommands.

Now that we are trying to use the linker script representation as the
canonycal one, there are a few loops looking for just OutputSectionCommands.

Create a

Keep a list of all OutputSectionCommands.

Now that we are trying to use the linker script representation as the
canonycal one, there are a few loops looking for just OutputSectionCommands.

Create a vector with just the OutputSectionCommands once that is
stable to simplify the rest of the code.

llvm-svn: 304181

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Use linker script commands in writeMapFile.

This converts the last (chronologically) user of OutputSections to use
the linker script commands instead.

The idea is to convert all uses after fabricat

Use linker script commands in writeMapFile.

This converts the last (chronologically) user of OutputSections to use
the linker script commands instead.

The idea is to convert all uses after fabricateDefaultCommands, so
that we have a single representation.

llvm-svn: 303384

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Use a forward declaration. NFC.

llvm-svn: 303363

Merge OutputSectionBase and OutputSection. NFC.

Now that all special sections are SyntheticSections, we only need one
OutputSection class.

llvm-svn: 296127

Implement -Map.

The format is not exactly the same as the one in bfd since bfd always
follows a linker script and prints it along.

llvm-svn: 291958