[llvm] [MIR2Vec][llvm-ir2vec] Add MIR2Vec support to llvm-ir2vec tool (PR #164025)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `polly-x86_64-linux-shared` running on `polly-x86_64-gce2` while building `llvm` at step 5 "build".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/97/builds/8935

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 5 (build) failure: 'ninja' (failure)
...
[4499/4541] Linking CXX shared module unittests/Analysis/InlineOrderPlugin.so
[4500/4541] Building CXX object unittests/CodeGen/CGPluginTest/Plugin/CMakeFiles/CGTestPlugin.dir/CodeGenTestPass.cpp.o
[4501/4541] Building CXX object unittests/CodeGen/CGPluginTest/Plugin/CMakeFiles/CGTestPlugin.dir/Plugin.cpp.o
[4502/4541] Linking CXX shared module lib/CGTestPlugin.so
[4503/4541] Building CXX object unittests/Passes/Plugins/TestPlugin/CMakeFiles/TestPlugin.dir/TestPlugin.cpp.o
[4504/4541] Building CXX object tools/llvm-ir2vec/CMakeFiles/llvm-ir2vec.dir/llvm-ir2vec.cpp.o
[4505/4541] Linking CXX shared module unittests/Passes/Plugins/TestPlugin.so
[4506/4541] Building CXX object unittests/Passes/Plugins/DoublerPlugin/CMakeFiles/DoublerPlugin.dir/DoublerPlugin.cpp.o
[4507/4541] Linking CXX shared module unittests/Passes/Plugins/DoublerPlugin.so
[4508/4541] Linking CXX executable bin/llvm-ir2vec
FAILED: bin/llvm-ir2vec 
: && /usr/bin/c++ -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-dangling-reference -Wno-redundant-move -Wno-pessimizing-move -Wno-array-bounds -Wno-stringop-overread -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wno-misleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG -fuse-ld=lld -Wl,--color-diagnostics     -Wl,--gc-sections tools/llvm-ir2vec/CMakeFiles/llvm-ir2vec.dir/llvm-ir2vec.cpp.o -o bin/llvm-ir2vec  -Wl,-rpath,"\$ORIGIN/../lib:/home/worker/workers/polly-x86_64-gce2/polly-x86_64-linux-shared/llvm.obj/lib:"  lib/libLLVMMIRParser.so.22.0git  lib/libLLVMX86AsmParser.so.22.0git  lib/libLLVMX86CodeGen.so.22.0git  lib/libLLVMNVPTXCodeGen.so.22.0git  lib/libLLVMX86Desc.so.22.0git  lib/libLLVMNVPTXDesc.so.22.0git  lib/libLLVMX86Info.so.22.0git  lib/libLLVMNVPTXInfo.so.22.0git  lib/libLLVMCodeGen.so.22.0git  lib/libLLVMAnalysis.so.22.0git  lib/libLLVMIRReader.so.22.0git  lib/libLLVMCore.so.22.0git  lib/libLLVMSupport.so.22.0git  -Wl,-rpath-link,/home/worker/workers/polly-x86_64-gce2/polly-x86_64-linux-shared/llvm.obj/lib && :
ld.lld: error: undefined symbol: llvm::Triple::Triple(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>&&)
>>> referenced by llvm-ir2vec.cpp
>>>               tools/llvm-ir2vec/CMakeFiles/llvm-ir2vec.dir/llvm-ir2vec.cpp.o:(main::'lambda'(llvm::StringRef, llvm::StringRef)::operator()(llvm::StringRef, llvm::StringRef) const (.isra.0))

ld.lld: error: undefined symbol: llvm::sys::getDefaultTargetTriple[abi:cxx11]()
>>> referenced by llvm-ir2vec.cpp
>>>               tools/llvm-ir2vec/CMakeFiles/llvm-ir2vec.dir/llvm-ir2vec.cpp.o:(main::'lambda'(llvm::StringRef, llvm::StringRef)::operator()(llvm::StringRef, llvm::StringRef) const (.isra.0))

ld.lld: error: undefined symbol: llvm::Triple::setTriple(llvm::Twine const&)
>>> referenced by llvm-ir2vec.cpp
>>>               tools/llvm-ir2vec/CMakeFiles/llvm-ir2vec.dir/llvm-ir2vec.cpp.o:(main::'lambda'(llvm::StringRef, llvm::StringRef)::operator()(llvm::StringRef, llvm::StringRef) const (.isra.0))
collect2: error: ld returned 1 exit status
[4509/4541] Building CXX object unittests/Support/DynamicLibrary/CMakeFiles/DynamicLibraryLib.dir/ExportedFuncs.cpp.o
[4510/4541] Linking CXX shared library lib/libclang-cpp.so.22.0git
ninja: build stopped: subcommand failed.
Cache directory:              /home/worker/.cache/ccache
Config file:                  /home/worker/.config/ccache/ccache.conf
System config file:           /etc/ccache.conf
Stats updated:                Thu Oct 23 12:21:15 2025
Cacheable calls:               3529 / 3531 (99.94%)
  Hits:                        3523 / 3529 (99.83%)
    Direct:                    3523 / 3523 (100.0%)
    Preprocessed:                 0 / 3523 ( 0.00%)
  Misses:                         6 / 3529 ( 0.17%)
Uncacheable calls:                2 / 3531 ( 0.06%)
  Unsupported code directive:     2 /    2 (100.0%)
Successful lookups:
  Direct:                      3523 / 3531 (99.77%)
  Preprocessed:                   0 /    6 ( 0.00%)
Local storage:
  Cache size (GiB):             3.2 /  5.0 (64.08%)
  Files:                      79606
  Hits:                        3523 / 3529 (99.83%)
  Misses:                         6 / 3529 ( 0.17%)
  Reads:                       7060
  Writes:                        12

```

</details>

https://github.com/llvm/llvm-project/pull/164025