[MC][Mips] Generate required IMAGE_REL_MIPS_PAIR relocation (#120876)

Add the required IMAGE_REL_MIPS_PAIR relocation after
IMAGE_REL_MIPS_REFHI/IMAGE_REL_MIPS_SECRELHI

Microsoft PE/COFF specifi

[MC][Mips] Generate required IMAGE_REL_MIPS_PAIR relocation (#120876)

Add the required IMAGE_REL_MIPS_PAIR relocation after
IMAGE_REL_MIPS_REFHI/IMAGE_REL_MIPS_SECRELHI

Microsoft PE/COFF specification says that the IMAGE_REL_MIPS_REFHI
relocation contains "the high 16 bits of the target's 32-bit virtual
address. [...] This relocation must be immediately followed by a PAIR
relocation whose SymbolTableIndex contains a 16-bit displacement which
is added to the upper 16 bits taken from the location being relocated."

Microsoft PE/COFF specification says that the IMAGE_REL_MIPS_SECRELHI
relocation contains "the high 16 bits of the 32-bit offset of the target
from the beginning of its section. A PAIR relocation must immediately
follow this on. The SymbolTableIndex of the PAIR relocation contains a
16-bit displacement, which is added to the upper 16 bits taken from the
location being relocated."

Behavior has been checked against Microsoft C compiler for MIPS.

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[coff] Don't try to write the obj if the assembler has errors (#123007)

The ASAN and MSAN tests have been failing after #122777 because some
fields are now set in `executePostLayoutBinding` which is

[coff] Don't try to write the obj if the assembler has errors (#123007)

The ASAN and MSAN tests have been failing after #122777 because some
fields are now set in `executePostLayoutBinding` which is skipped by the
assembler if it had errors but read in `writeObject`

Since the compilation has failed anyway, skip `writeObject` if the
assembler had errors.

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Reapply "[aarch64][win] Add support for import call optimization (equivalent to MSVC /d2ImportCallOptimization) (#121516)" (#122777)

This reverts commit 2f7ade4b5e399962e18f5f9a0ab0b7335deece51.

Fi

Reapply "[aarch64][win] Add support for import call optimization (equivalent to MSVC /d2ImportCallOptimization) (#121516)" (#122777)

This reverts commit 2f7ade4b5e399962e18f5f9a0ab0b7335deece51.

Fix is available in #122762

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Revert "[aarch64][win] Add support for import call optimization (equivalent to MSVC /d2ImportCallOptimization) (#121516)"

Breaks sanitizer build: https://lab.llvm.org/buildbot/#/builders/52/builds/5

Revert "[aarch64][win] Add support for import call optimization (equivalent to MSVC /d2ImportCallOptimization) (#121516)"

Breaks sanitizer build: https://lab.llvm.org/buildbot/#/builders/52/builds/5179

This reverts commits:
5ee0a71df919a328c714e25f0935c21e586cc18b
d997a722c194feec5f3a94dec5acdce59ac5e55b

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[aarch64][win] Add support for import call optimization (equivalent to MSVC /d2ImportCallOptimization) (#121516)

This change implements import call optimization for AArch64 Windows
(equivalent to th

[aarch64][win] Add support for import call optimization (equivalent to MSVC /d2ImportCallOptimization) (#121516)

This change implements import call optimization for AArch64 Windows
(equivalent to the undocumented MSVC `/d2ImportCallOptimization` flag).

Import call optimization adds additional data to the binary which can be
used by the Windows kernel loader to rewrite indirect calls to imported
functions as direct calls. It uses the same [Dynamic Value Relocation
Table mechanism that was leveraged on x64 to implement
`/d2GuardRetpoline`](https://techcommunity.microsoft.com/blog/windowsosplatform/mitigating-spectre-variant-2-with-retpoline-on-windows/295618).

The change to the obj file is to add a new `.impcall` section with the
following layout:
```cpp
// Per section that contains calls to imported functions:
// uint32_t SectionSize: Size in bytes for information in this section.
// uint32_t Section Number
// Per call to imported function in section:
// uint32_t Kind: the kind of imported function.
// uint32_t BranchOffset: the offset of the branch instruction in its
// parent section.
// uint32_t TargetSymbolId: the symbol id of the called function.
```

NOTE: If the import call optimization feature is enabled, then the
`.impcall` section must be emitted, even if there are no calls to
imported functions.

The implementation is split across a few parts of LLVM:
* During AArch64 instruction selection, the `GlobalValue` for each call
to a global is recorded into the Extra Information for that node.
* During lowering to machine instructions, the called global value for
each call is noted in its containing `MachineFunction`.
* During AArch64 asm printing, if the import call optimization feature
is enabled:
- A (new) `.impcall` directive is emitted for each call to an imported
function.
- The `.impcall` section is emitted with its magic header (but is not
filled in).
* During COFF object writing, the `.impcall` section is filled in based
on each `.impcall` directive that were encountered.

The `.impcall` section can only be filled in when we are writing the
COFF object as it requires the actual section numbers, which are only
assigned at that point (i.e., they don't exist during asm printing).

I had tried to avoid using the Extra Information during instruction
selection and instead implement this either purely during asm printing
or in a `MachineFunctionPass` (as suggested in [on the
forums](https://discourse.llvm.org/t/design-gathering-locations-of-instructions-to-emit-into-a-section/83729/3))
but this was not possible due to how loading and calling an imported
function works on AArch64. Specifically, they are emitted as `ADRP` +
`LDR` (to load the symbol) then a `BR` (to do the call), so at the point
when we have machine instructions, we would have to work backwards
through the instructions to discover what is being called. An initial
prototype did work by inspecting instructions; however, it didn't
correctly handle the case where the same function was called twice in a
row, which caused LLVM to elide the `ADRP` + `LDR` and reuse the
previously loaded address. Worse than that, sometimes for the
double-call case LLVM decided to spill the loaded address to the stack
and then reload it before making the second call. So, instead of trying
to implement logic to discover where the value in a register came from,
I instead recorded the symbol being called at the last place where it
was easy to do: instruction selection.

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[MC] Remove redundant MCSection::empty check. NFC

The section cannot be empty due to allocInitialFragment.

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

Identified with misc-include-cleaner.

MCAssembler: Move CGProfile to MCObjectWriter

MCAssembler: Move FileNames and CompilerVersion to MCObjectWriter

[MC] Export llvm::WinCOFFObjectWriter and access it from MCWinCOFFStreamer

Similar to commit 28fcafb50274be2520117eacb0a886adafefe59d (2011) for
MachObjectWriter. MCWinCOFFStreamer can now access Wi

[MC] Export llvm::WinCOFFObjectWriter and access it from MCWinCOFFStreamer

Similar to commit 28fcafb50274be2520117eacb0a886adafefe59d (2011) for
MachObjectWriter. MCWinCOFFStreamer can now access WinCOFFObjectWriter
directly without holding object file format specific inforamtion in
MCAssembler (e.g. IncrementalLinkerCompatible).

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MCAssembler: Remove unneeded non-const iterators for Sections and misleading size()

The pointers cannot be mutated even if the dereferenced MCSection can.

WinCOFFObjectWriter: replace the MCAsmLayout parameter with MCAssembler

[MC] Remove MCAsmLayout::{getSymbolOffset,getBaseSymbol}

The MCAsmLayout::* forwarders added by
67957a45ee1ec42ae1671cdbfa0d73127346cc95 have all been removed.

[MC] Remove MCAsmLayout::{getSectionFileSize,getSectionAddressSize}

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

[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.

[MC,COFF] Change how we handle section symbols

13a79bbfe583e1d8cc85d241b580907260065eb8 (2017) unified `BeginSymbol` and
section symbol for ELF. This patch does the same for COFF.

* In getCOFFSecti

[MC,COFF] Change how we handle section symbols

13a79bbfe583e1d8cc85d241b580907260065eb8 (2017) unified `BeginSymbol` and
section symbol for ELF. This patch does the same for COFF.

* In getCOFFSection, all sections now have a `BeginSymbol` (section
symbol). We do not need a dummy symbol name when `getBeginSymbol` is
needed (used by AsmParser::Run and DWARF generation).
* Section symbols are in the global symbol table. `call .text` will
reference the section symbol instead of an undefined symbol. This
matches GNU assembler. Unlike GNU, redefining the section symbol will
cause a "symbol 'foo0' is already defined" error (see
`section-sym-err.s`).

Pull Request: https://github.com/llvm/llvm-project/pull/96459

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[MC,COFF] Register .llvm.call-graph-profile in finalizeImpl

All sections should have been created before MCAssembler::layout so that
every section has an ordinal. Registering the section in
WinCOFFO

[MC,COFF] Register .llvm.call-graph-profile in finalizeImpl

All sections should have been created before MCAssembler::layout so that
every section has an ordinal. Registering the section in
WinCOFFObjectWriter::executePostLayoutBinding is a hack.

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[MC] Remove SectionKind from MCSection (#96067)

There are only three actual uses of the section kind in MCSection:
isText(), XCOFF, and WebAssembly. Store isText() in the MCSection, and
store othe

[MC] Remove SectionKind from MCSection (#96067)

There are only three actual uses of the section kind in MCSection:
isText(), XCOFF, and WebAssembly. Store isText() in the MCSection, and
store other info in the actual section variants where required.

ELF and COFF flags also encode all relevant information, so for these
two section variants, remove the SectionKind parameter entirely.

This allows to remove the string switch (which is unnecessary and
inaccurate) from createELFSectionImpl. This was introduced in
[D133456](https://reviews.llvm.org/D133456), but apparently, it was
never hit for non-writable sections anyway and the resulting kind was
never used.

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[MC] Add MCFragment allocation helpers

`allocFragment` might be changed to a placement new when the allocation
strategy changes.

`allocInitialFragment` is to deduplicate the following pattern
```

[MC] Add MCFragment allocation helpers

`allocFragment` might be changed to a placement new when the allocation
strategy changes.

`allocInitialFragment` is to deduplicate the following pattern
```
auto *F = new MCDataFragment();
Result->addFragment(*F);
F->setParent(Result);
```

Pull Request: https://github.com/llvm/llvm-project/pull/95197

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[MC] Remove getFragmentList uses. NFC

[MC][COFF][AArch64] Treat ARM64EC/X as ARM64 for relocations (#86019)

Since ARM64EC/X objects use regular ARM64 relocations, any special
handling must be done for them too.