[flang][OpenMP] Move two utilities from Semantics to Parser, NFC (#168549)

Move `GetInnermostExecPart` and `IsStrictlyStructuredBlock` from
Semantics/openmp-utils.* to Parser/openmp-utils.*. These two only depend
on the AST contents and properties.

Author: kparzysz

flang/include/flang/Parser/openmp-utils.h

@@ -137,6 +137,8 @@ const T *GetFirstArgument(const OmpDirectiveSpecification &spec) {
 
 const BlockConstruct *GetFortranBlockConstruct(
     const ExecutionPartConstruct &epc);
+const Block &GetInnermostExecPart(const Block &block);
+bool IsStrictlyStructuredBlock(const Block &block);
 
 const OmpCombinerExpression *GetCombinerExpr(
     const OmpReductionSpecifier &rspec);

flang/include/flang/Semantics/openmp-utils.h

@@ -97,8 +97,6 @@ const SomeExpr *HasStorageOverlap(
     const SomeExpr &base, llvm::ArrayRef<SomeExpr> exprs);
 bool IsAssignment(const parser::ActionStmt *x);
 bool IsPointerAssignment(const evaluate::Assignment &x);
-const parser::Block &GetInnermostExecPart(const parser::Block &block);
-bool IsStrictlyStructuredBlock(const parser::Block &block);
 } // namespace omp
 } // namespace Fortran::semantics
 

flang/lib/Parser/openmp-utils.cpp

@@ -93,6 +93,34 @@ const BlockConstruct *GetFortranBlockConstruct(
   return nullptr;
 }
 
+/// parser::Block is a list of executable constructs, parser::BlockConstruct
+/// is Fortran's BLOCK/ENDBLOCK construct.
+/// Strip the outermost BlockConstructs, return the reference to the Block
+/// in the executable part of the innermost of the stripped constructs.
+/// Specifically, if the given `block` has a single entry (it's a list), and
+/// the entry is a BlockConstruct, get the Block contained within. Repeat
+/// this step as many times as possible.
+const Block &GetInnermostExecPart(const Block &block) {
+  const Block *iter{&block};
+  while (iter->size() == 1) {
+    const ExecutionPartConstruct &ep{iter->front()};
+    if (auto *bc{GetFortranBlockConstruct(ep)}) {
+      iter = &std::get<Block>(bc->t);
+    } else {
+      break;
+    }
+  }
+  return *iter;
+}
+
+bool IsStrictlyStructuredBlock(const Block &block) {
+  if (block.size() == 1) {
+    return GetFortranBlockConstruct(block.front()) != nullptr;
+  } else {
+    return false;
+  }
+}
+
 const OmpCombinerExpression *GetCombinerExpr(
     const OmpReductionSpecifier &rspec) {
   return addr_if(std::get<std::optional<OmpCombinerExpression>>(rspec.t));

flang/lib/Semantics/check-omp-atomic.cpp

@@ -19,6 +19,7 @@
 #include "flang/Evaluate/rewrite.h"
 #include "flang/Evaluate/tools.h"
 #include "flang/Parser/char-block.h"
+#include "flang/Parser/openmp-utils.h"
 #include "flang/Parser/parse-tree.h"
 #include "flang/Semantics/openmp-utils.h"
 #include "flang/Semantics/symbol.h"
@@ -41,6 +42,7 @@
 
 namespace Fortran::semantics {
 
+using namespace Fortran::parser::omp;
 using namespace Fortran::semantics::omp;
 
 namespace operation = Fortran::evaluate::operation;

flang/lib/Semantics/openmp-utils.cpp

@@ -496,32 +496,4 @@ bool IsPointerAssignment(const evaluate::Assignment &x) {
   return std::holds_alternative<evaluate::Assignment::BoundsSpec>(x.u) ||
       std::holds_alternative<evaluate::Assignment::BoundsRemapping>(x.u);
 }
-
-/// parser::Block is a list of executable constructs, parser::BlockConstruct
-/// is Fortran's BLOCK/ENDBLOCK construct.
-/// Strip the outermost BlockConstructs, return the reference to the Block
-/// in the executable part of the innermost of the stripped constructs.
-/// Specifically, if the given `block` has a single entry (it's a list), and
-/// the entry is a BlockConstruct, get the Block contained within. Repeat
-/// this step as many times as possible.
-const parser::Block &GetInnermostExecPart(const parser::Block &block) {
-  const parser::Block *iter{&block};
-  while (iter->size() == 1) {
-    const parser::ExecutionPartConstruct &ep{iter->front()};
-    if (auto *bc{GetFortranBlockConstruct(ep)}) {
-      iter = &std::get<parser::Block>(bc->t);
-    } else {
-      break;
-    }
-  }
-  return *iter;
-}
-
-bool IsStrictlyStructuredBlock(const parser::Block &block) {
-  if (block.size() == 1) {
-    return GetFortranBlockConstruct(block.front()) != nullptr;
-  } else {
-    return false;
-  }
-}
 } // namespace Fortran::semantics::omp