Avoids more Triple->string->Triple round trip. This
is a continuation of f137c3d592e96330e450a8fd63ef7e8877fc1908

Add missing dependencies to unittest target
Original patch broke BUILD_SHARED bots and required revert #147947

Reverts llvm/llvm-project#139059

This broke
https://lab.llvm.org/buildbot/#/builders/10/builds/9125/steps/8/logs/stdio

The bot does a SHARED_LIBS=ON build. I can reproduce locally with the
CMake cache file in offload/cmake/caches/AMDGPUBot.cmake as the build
config.

This PR exposes the backend pass config to plugins via a callback.
Plugin authors can register a callback that is being triggered before
the target backend adds their passes to the pipeline. In the callback
they then get access to the `TargetMachine`, the `PassManager`, and the
`TargetPassConfig`. This allows plugins to call
`TargetPassConfig::insertPass`, which is honored in the subsequent
`addPass` of the main backend. We implemented this using the legacy pass
manager since backends still use it as the default.

Currently the default exception handling type is scattered
across the backends in MCAsmInfo constructors. Allow this
to be computed from the triple so the IR can centrally determine
the set of ABI calls.

Manually submitting, closes #147225

Replace "concept based polymorphism" with simpler PImpl idiom.

This pursues two goals:
* Enforce static type checking. Previously, target implementations hid
base class methods and type checking was impossible. Now that they
override the methods, the compiler will complain on mismatched
signatures.
* Make the code easier to navigate. Previously, if you asked your
favorite LSP server to show a method (e.g. `getInstructionCost()`), it
would show you methods from `TTI`, `TTI::Concept`, `TTI::Model`,
`TTIImplBase`, and target overrides. Now it is two less :)

There are three commits to hopefully simplify the review.

The first commit removes `TTI::Model`. This is done by deriving
`TargetTransformInfoImplBase` from `TTI::Concept`. This is possible
because they implement the same set of interfaces with identical
signatures.

The first commit makes `TargetTransformImplBase` polymorphic, which
means all derived classes should `override` its methods. This is done in
second commit to make the first one smaller. It appeared infeasible to
extract this into a separate PR because the first commit landed
separately would result in tons of `-Woverloaded-virtual` warnings (and
break `-Werror` builds).

The third commit eliminates `TTI::Concept` by merging it with the only
derived class `TargetTransformImplBase`. This commit could be extracted
into a separate PR, but it touches the same lines in
`TargetTransformInfoImpl.h` (removes `override` added by the second
commit and adds `virtual`), so I thought it may make sense to land these
two commits together.

Pull Request: https://github.com/llvm/llvm-project/pull/136674

... to clarify ownership, aligning with other parameters. Using
`std::unique_ptr` encourages users to manage `createMCInstPrinter` with
a unique_ptr instead of a raw pointer, reducing the risk of memory
leaks.

* llvm-mc: fix a leak and update llvm/test/tools/llvm-mc/disassembler-options.test
* #121078 copied the llvm-mc code to CodeGenTargetMachineImpl and made
  the same mistake. Fixed by 2b8cc651dca0c000ee18ec79bd5de4826156c9d6

Using unique_ptr requires #include MCInstPrinter.h in a few translation
units.

* Delete a createAsmStreamer overload I deprecated in 2024
* SystemZMCTargetDesc.cpp: rename to `createSystemZAsmStreamer` to fix
  an overload conflict.

Pull Request: https://github.com/llvm/llvm-project/pull/135128

For many targets, llvm-objdump and llvm-mc
(https://reviews.llvm.org/D103004) support -M no-aliases (e.g.
`RISCVInstPrinter::applyTargetSpecificCLOption`).

This patch implements -M for llc.

While here, rename "DisassemblerOptions" in llvm-mc to the more
appropriate "InstPrinterOptions". For llvm-mc --assemble, there is no
disassembler involved.

Pull Request: https://github.com/llvm/llvm-project/pull/121078