[MC] Avoid repeated hash lookups (NFC) (#123502)

[MC] Remove unused includes (NFC) (#116317)

Identified with misc-include-cleaner.

[llvm][ELF] Add ELF header/section header table size statistics (#109345)

Followup to #102363. This makes the `elf-object-writer.*Bytes` stats sum
up to `assembler.ObjectBytes`.

[NFC][ELF] Rename some ELFWriter methods (#109332)

More consistent casing + more accurate names.

[MIPS] Optimize sortRelocs for o32

The o32 ABI specifies:

> Each relocation type of R_MIPS_HI16 must have an associated R_MIPS_LO16 entry immediately following it in the list of relocations. [...]

[MIPS] Optimize sortRelocs for o32

The o32 ABI specifies:

> Each relocation type of R_MIPS_HI16 must have an associated R_MIPS_LO16 entry immediately following it in the list of relocations. [...] the addend AHL is computed as (AHI << 16) + (short)ALO

In practice, the high-part and low-part relocations may not be adjacent
in assembly files, requiring the assembler to reorder relocations.
http://reviews.llvm.org/D19718 performed the reordering, but did not
optimize for the common case where a %lo immediately follows its
matching %hi. The quadratic time complexity could make sections with
many relocations very slow to process.

This patch implements the fast path, simplifies the code, and makes the
behavior more similar to GNU assembler (for the .rel.mips_hilo_8b test).
We also remove `OriginalSymbol`, removing overhead for other targets.

Fix #104562

Pull Request: https://github.com/llvm/llvm-project/pull/104723

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[MC] Remove ELFRelocationEntry::OriginalAddend

For MIPS's o32 ABI (REL), https://reviews.llvm.org/D19718 introduced
`OriginalAddend` to find the matching R_MIPS_LO16 relocation for
R_MIPS_GOT16 when

[MC] Remove ELFRelocationEntry::OriginalAddend

For MIPS's o32 ABI (REL), https://reviews.llvm.org/D19718 introduced
`OriginalAddend` to find the matching R_MIPS_LO16 relocation for
R_MIPS_GOT16 when STT_SECTION conversion is applicable.

lw $2, %lo(local1)
lui $2, %got(local1)

However, we could just store the original `Addend` in
`ELFRelocationEntry` and remove `OriginalAddend`.

Note: The relocation ordering algorithm in
https://reviews.llvm.org/D19718 is inefficient (#104562), which will be
addressed by another patch.

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[llvm][ELF] Add statistics on various section sizes (#102363)

Useful with other infrastructure that consume LLVM statistics to get an
idea of distribution of section sizes.

The breakdown of vari

[llvm][ELF] Add statistics on various section sizes (#102363)

Useful with other infrastructure that consume LLVM statistics to get an
idea of distribution of section sizes.

The breakdown of various section types is subject to change, this is
just an initial go at gather some sort of stats.

Example stats compiling X86ISelLowering.cpp (-g1):

```
"elf-object-writer.AllocROBytes": 308268,
"elf-object-writer.AllocRWBytes": 6240,
"elf-object-writer.AllocTextBytes": 1659203,
"elf-object-writer.DebugBytes": 3180386,
"elf-object-writer.OtherBytes": 5862,
"elf-object-writer.RelocationBytes": 2623440,
"elf-object-writer.StrtabBytes": 228599,
"elf-object-writer.SymtabBytes": 120336,
"elf-object-writer.UnwindBytes": 85216,
```

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[MC,ARM] Move SHF_ARM_PUECODE change for .text to ARMTargetELFStreamer::finish

and remove MCELFObjectWriter::addTargetSectionFlags.

ELFObjectWriter: Remove unneeded subclasses

MCAssembler: Move FileNames and CompilerVersion to MCObjectWriter

MCAssembler: Move Symvers to ELFObjectWriter

Similar to c473e75adeaf2998e4fb444b0bdbf2dd19312e50

MCAssmembler: Move ELFHeaderEFlags to ELFObjectWriter

Now that MCELFStreamer can access ELFObjectWriter (commit
70c52b62c5669993e341664a63bfbe5245e32884), we can move ELFHeaderEFlags
there.

[MC] Export llvm::ELFObjectWriter

Similar to commit 28fcafb50274be2520117eacb0a886adafefe59d (2011) for
MachObjectWriter and commit 9539a7796094ff5fb59d9c685140ea2e214b945c for
WinCOFFObjectWriter.

[MC] Export llvm::ELFObjectWriter

Similar to commit 28fcafb50274be2520117eacb0a886adafefe59d (2011) for
MachObjectWriter and commit 9539a7796094ff5fb59d9c685140ea2e214b945c for
WinCOFFObjectWriter.

MCELFStreamer can now access ELFObjectWriter directly without adding
ELF-specific markGnuAbi (https://reviews.llvm.org/D97976) and
setOverrideABIVersion to MCObjectWriter.

A few member variables have to be made public since we cannot use a
friend declaration for ELFWriter.

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[MC,ELF] Extract CREL encoder code

The extracted ELFObjectWriter.cpp code will be reused by llvm-objcopy
support (#97521).

[MC][ELF] Eliminate some hash maps from ELFObjectWriter (#97421)

Remove some maps. Mostly cleanup, only a slight performance win.

- Replace SectionIndexMap with layout order: The section layout o

[MC][ELF] Eliminate some hash maps from ELFObjectWriter (#97421)

Remove some maps. Mostly cleanup, only a slight performance win.

- Replace SectionIndexMap with layout order: The section layout order is
only used in MachO, so we can repurpose the field as section table
index.
- Store section offsets in MCSectionELF: No need for a map, and
especially not a std::map. Direct access to the underlying (and easily
modifyable) data structure is always faster.
- Improve storage of groups: There's no point in having a DenseMap, the
number of sections and groups are reasonably small to use vectors.

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[MC] Remove unused MCAsmLayout declarations and includes

MCExpr::evaluateKnownAbsolute: replace the MCAsmLayout parameter with MCAssembler

and add a comment.

[MC] Remove the MCAsmLayout parameter from MCObjectWriter::executePostLayoutBinding

[MC,llvm-readobj,yaml2obj] Support CREL relocation format

CREL is a compact relocation format for the ELF object file format.

This patch adds integrated assembler support (using the RELA form)
avai

[MC,llvm-readobj,yaml2obj] Support CREL relocation format

CREL is a compact relocation format for the ELF object file format.

This patch adds integrated assembler support (using the RELA form)
available with `llvm-mc -filetype=obj -crel a.s -o a.o`.
A dependent patch will add `clang -c -Wa,--crel,--allow-experimental-crel`.

Also add llvm-readobj support (for both REL and RELA forms) to
facilitate testing the assembler. Additionally, yaml2obj gains support
for the RELA form to aid testing with llvm-readobj.

We temporarily assign the section type code 0x40000020 from the generic
range to `SHT_CREL`. We avoided using `SHT_LLVM_` or `SHT_GNU_` to
avoid code churn and maintain broader applicability for interested psABIs.
Similarly, `DT_CREL` is temporarily 0x40000026.

LLVM will change the code and break compatibility. This is not an issue
if all relocatable files using CREL are regenerated (aka no prebuilt
relocatable files).

Link: https://discourse.llvm.org/t/rfc-crel-a-compact-relocation-format-for-elf/77600

Pull Request: https://github.com/llvm/llvm-project/pull/91280

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ELFObjectWriter: Use DenseMap+SmallVector. NFC

[MC] Remove the MCAsmLayout parameter from ELFObjectWriter

[MC] Remove the MCAsmLayout parameter from MCObjectWriter::{writeObject,writeSectionData}

[MC] Remove the MCAsmLayout parameter from MCObjectWriter::recordRelocation

[MC] Start merging MCAsmLayout into MCAssembler

Follow-up to 10c894cffd0f4bef21b54a43b5780240532e44cf.

MCAsmLayout, introduced by ac8a95498a99eb16dff9d3d0186616645d200b6e
(2010), provides APIs to c

[MC] Start merging MCAsmLayout into MCAssembler

Follow-up to 10c894cffd0f4bef21b54a43b5780240532e44cf.

MCAsmLayout, introduced by ac8a95498a99eb16dff9d3d0186616645d200b6e
(2010), provides APIs to compute fragment/symbol/section offsets.
The separate class is cumbersome and passing it around has overhead.
Let's remove it as the underlying implementation is tightly coupled with
MCAsmLayout anyway.

Some forwarders are added to ease migration.

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[MC] Simplify isSymbolRefDifferenceFullyResolvedImpl overloads. NFC

The base implementation is simple. Just inline it.