[clang][OpenMP] Prototype #2 of directive splitting

[kparzysz]

This is proto #1 minus the introduction of opaque AST nodes.

This isn't 100% finished, but it should be enough to illustrate the changes needed to implement the feature.

Proto #1: #108855

[github-actions]

⚠️ C/C++ code formatter, clang-format found issues in your code. ⚠️

You can test this locally with the following command:

git-clang-format --diff 0baefe179b9f2e295ef4bbd659ca98a31e1547d0 b17dc927ab1c2c84e8ac9174f212be538c67efc0 --extensions h,cpp -- clang/lib/Sema/SemaOpenMPExt.cpp clang/lib/Sema/SemaOpenMPExt.h clang/include/clang/AST/OpenMPClause.h clang/include/clang/AST/Stmt.h clang/include/clang/Basic/OpenMPKinds.h clang/include/clang/Sema/SemaOpenMP.h clang/lib/AST/Stmt.cpp clang/lib/Basic/OpenMPKinds.cpp clang/lib/CodeGen/CGStmtOpenMP.cpp clang/lib/Parse/ParseOpenMP.cpp clang/lib/Sema/SemaExpr.cpp clang/lib/Sema/SemaOpenMP.cpp clang/lib/Sema/TreeTransform.h llvm/include/llvm/Frontend/OpenMP/ConstructDecompositionT.h llvm/include/llvm/Frontend/OpenMP/OMP.h llvm/lib/Frontend/OpenMP/OMP.cpp

View the diff from clang-format here.

diff --git a/clang/include/clang/Sema/SemaOpenMP.h b/clang/include/clang/Sema/SemaOpenMP.h
index 62dc569fef..75bdc6e430 100644
--- a/clang/include/clang/Sema/SemaOpenMP.h
+++ b/clang/include/clang/Sema/SemaOpenMP.h
@@ -1433,9 +1433,9 @@ public:
 
     VariableImplicitInfo &include(const VariableImplicitInfo &Other);
 
-  #ifndef NDEBUG
+#ifndef NDEBUG
     bool empty() const;
-  #endif
+#endif
 
   private:
     std::pair<Stmt *, Decl *> getDecl(Expr *E);
diff --git a/llvm/include/llvm/Frontend/OpenMP/ConstructDecompositionT.h b/llvm/include/llvm/Frontend/OpenMP/ConstructDecompositionT.h
index e15f78909d..5b5960da9d 100644
--- a/llvm/include/llvm/Frontend/OpenMP/ConstructDecompositionT.h
+++ b/llvm/include/llvm/Frontend/OpenMP/ConstructDecompositionT.h
@@ -96,7 +96,8 @@ struct ConstructDecompositionT {
                           llvm::omp::Directive dir,
                           llvm::ArrayRef<ClauseTy> clauses,
                           bool makeImplicit = true)
-      : version(ver), construct(dir), makeImplicit(makeImplicit), helper(helper) {
+      : version(ver), construct(dir), makeImplicit(makeImplicit),
+        helper(helper) {
     for (const ClauseTy &clause : clauses)
       nodes.push_back(&clause);
 
@@ -253,7 +254,7 @@ private:
 
   uint32_t version;
   llvm::omp::Directive construct;
-  bool makeImplicit;   // Whether to create implicit clauses.
+  bool makeImplicit; // Whether to create implicit clauses.
   HelperType &helper;
   ListT<LeafReprInternal> leafs;
   tomp::ListT<const ClauseTy *> nodes;