[llvm] [CGData] Refactor Global Merge Functions (PR #115750)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-x86_64-debian-fast` running on `gribozavr4` while building `llvm` at step 5 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/56/builds/12175

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

```
Step 5 (build-unified-tree) failure: build (failure)
...
  /// FIXME: Eventually we want to drop \param Target and deduce it from
                                               ^~~~~~
/b/1/clang-x86_64-debian-fast/llvm.src/clang/include/clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h:991:8: note: previous documentation
  /// \param Target The region where the object should be constructed. If NULL,
       ^     ~~~~~~
/b/1/clang-x86_64-debian-fast/llvm.src/clang/include/clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h:998:14: warning: parameter 'ElemRef.' not found in the function declaration [-Wdocumentation]
  /// \param ElemRef.
             ^~~~~~~~
11 warnings generated.
14.266 [1952/96/4001] Building CXX object lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/GlobalMergeFunctions.cpp.o
FAILED: lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/GlobalMergeFunctions.cpp.o 
CCACHE_CPP2=yes CCACHE_HASHDIR=yes /usr/bin/ccache /usr/bin/clang++ -DGTEST_HAS_RTTI=0 -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/b/1/clang-x86_64-debian-fast/llvm.obj/lib/CodeGen -I/b/1/clang-x86_64-debian-fast/llvm.src/llvm/lib/CodeGen -I/b/1/clang-x86_64-debian-fast/llvm.obj/include -I/b/1/clang-x86_64-debian-fast/llvm.src/llvm/include -std=c++11 -Wdocumentation -Wno-documentation-deprecated-sync -fPIC -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wc++98-compat-extra-semi -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG  -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -std=c++17 -MD -MT lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/GlobalMergeFunctions.cpp.o -MF lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/GlobalMergeFunctions.cpp.o.d -o lib/CodeGen/CMakeFiles/LLVMCodeGen.dir/GlobalMergeFunctions.cpp.o -c /b/1/clang-x86_64-debian-fast/llvm.src/llvm/lib/CodeGen/GlobalMergeFunctions.cpp
/b/1/clang-x86_64-debian-fast/llvm.src/llvm/lib/CodeGen/GlobalMergeFunctions.cpp:450:34: error: reference to local binding 'FI' declared in enclosing function 'llvm::GlobalMergeFunc::merge'
              assert(InstIndex < FI.IndexInstruction->size());
                                 ^
/b/1/clang-x86_64-debian-fast/llvm.src/llvm/lib/CodeGen/GlobalMergeFunctions.cpp:440:20: note: 'FI' declared here
    for (auto &[F, FI] : Funcs) {
                   ^
/b/1/clang-x86_64-debian-fast/llvm.src/llvm/lib/CodeGen/GlobalMergeFunctions.cpp:451:28: error: reference to local binding 'FI' declared in enclosing function 'llvm::GlobalMergeFunc::merge'
              auto *Inst = FI.IndexInstruction->lookup(InstIndex);
                           ^
/b/1/clang-x86_64-debian-fast/llvm.src/llvm/lib/CodeGen/GlobalMergeFunctions.cpp:440:20: note: 'FI' declared here
    for (auto &[F, FI] : Funcs) {
                   ^
2 errors generated.
14.267 [1952/95/4002] Building CXX object tools/clang/lib/StaticAnalyzer/Checkers/CMakeFiles/obj.clangStaticAnalyzerCheckers.dir/BlockInCriticalSectionChecker.cpp.o
In file included from /b/1/clang-x86_64-debian-fast/llvm.src/clang/lib/StaticAnalyzer/Checkers/BlockInCriticalSectionChecker.cpp:18:
In file included from /b/1/clang-x86_64-debian-fast/llvm.src/clang/include/clang/StaticAnalyzer/Core/BugReporter/BugType.h:18:
In file included from /b/1/clang-x86_64-debian-fast/llvm.src/clang/include/clang/StaticAnalyzer/Core/Checker.h:16:
In file included from /b/1/clang-x86_64-debian-fast/llvm.src/clang/include/clang/Analysis/ProgramPoint.h:17:
In file included from /b/1/clang-x86_64-debian-fast/llvm.src/clang/include/clang/Analysis/AnalysisDeclContext.h:22:
In file included from /b/1/clang-x86_64-debian-fast/llvm.src/clang/include/clang/Analysis/CFG.h:17:
In file included from /b/1/clang-x86_64-debian-fast/llvm.src/clang/include/clang/AST/Attr.h:18:
In file included from /b/1/clang-x86_64-debian-fast/llvm.src/clang/include/clang/AST/Decl.h:17:
/b/1/clang-x86_64-debian-fast/llvm.src/clang/include/clang/AST/APValue.h:372:14: warning: parameter 'UninitArray' not found in the function declaration [-Wdocumentation]
  /// \param UninitArray Marker. Pass an empty UninitArray.
             ^~~~~~~~~~~
/b/1/clang-x86_64-debian-fast/llvm.src/clang/include/clang/AST/APValue.h:380:14: warning: parameter 'UninitStruct' not found in the function declaration [-Wdocumentation]
  /// \param UninitStruct Marker. Pass an empty UninitStruct.
             ^~~~~~~~~~~~
In file included from /b/1/clang-x86_64-debian-fast/llvm.src/clang/lib/StaticAnalyzer/Checkers/BlockInCriticalSectionChecker.cpp:18:
In file included from /b/1/clang-x86_64-debian-fast/llvm.src/clang/include/clang/StaticAnalyzer/Core/BugReporter/BugType.h:18:
In file included from /b/1/clang-x86_64-debian-fast/llvm.src/clang/include/clang/StaticAnalyzer/Core/Checker.h:16:
In file included from /b/1/clang-x86_64-debian-fast/llvm.src/clang/include/clang/Analysis/ProgramPoint.h:17:
In file included from /b/1/clang-x86_64-debian-fast/llvm.src/clang/include/clang/Analysis/AnalysisDeclContext.h:22:
In file included from /b/1/clang-x86_64-debian-fast/llvm.src/clang/include/clang/Analysis/CFG.h:18:
In file included from /b/1/clang-x86_64-debian-fast/llvm.src/clang/include/clang/AST/ExprCXX.h:21:
In file included from /b/1/clang-x86_64-debian-fast/llvm.src/clang/include/clang/AST/DeclCXX.h:22:
/b/1/clang-x86_64-debian-fast/llvm.src/clang/include/clang/AST/Expr.h:5228:21: warning: '@endcode' command does not terminate a verbatim text block [-Wdocumentation]

```

</details>

https://github.com/llvm/llvm-project/pull/115750