[flang] Move genCommonBlockMember from OpenMP to ConvertVariable, NFC (#74488)

The function `genCommonBlockMember` is not specific to OpenMP, and it
could very well be a common utility. Move it to ConvertVariable.cpp
where it logically belongs.

Author: kparzysz

flang/include/flang/Lower/ConvertVariable.h

@@ -19,6 +19,7 @@
 
 #include "flang/Lower/Support/Utils.h"
 #include "flang/Optimizer/Dialect/FIRAttr.h"
+#include "flang/Semantics/symbol.h"
 #include "mlir/IR/Value.h"
 #include "llvm/ADT/DenseMap.h"
 
@@ -29,7 +30,12 @@ class GlobalOp;
 class FortranVariableFlagsAttr;
 } // namespace fir
 
-namespace Fortran ::lower {
+namespace Fortran {
+namespace semantics {
+class Scope;
+} // namespace semantics
+
+namespace lower {
 class AbstractConverter;
 class CallerInterface;
 class StatementContext;
@@ -66,6 +72,14 @@ void defineCommonBlocks(
     const std::vector<std::pair<semantics::SymbolRef, std::size_t>>
         &commonBlocks);
 
+/// The COMMON block is a global structure. \p commonValue is the base address
+/// of the COMMON block. As the offset from the symbol \p sym, generate the
+/// COMMON block member value (commonValue + offset) for the symbol.
+mlir::Value genCommonBlockMember(AbstractConverter &converter,
+                                 mlir::Location loc,
+                                 const Fortran::semantics::Symbol &sym,
+                                 mlir::Value commonValue);
+
 /// Lower a symbol attributes given an optional storage \p and add it to the
 /// provided symbol map. If \preAlloc is not provided, a temporary storage will
 /// be allocated. This is a low level function that should only be used if
@@ -138,5 +152,6 @@ void genDeclareSymbol(Fortran::lower::AbstractConverter &converter,
 /// Cray pointer symbol. Assert if the pointer symbol cannot be found.
 Fortran::semantics::SymbolRef getCrayPointer(Fortran::semantics::SymbolRef sym);
 
-} // namespace Fortran::lower
+} // namespace lower
+} // namespace Fortran
 #endif // FORTRAN_LOWER_CONVERT_VARIABLE_H

flang/lib/Lower/ConvertVariable.cpp

@@ -1331,6 +1331,28 @@ void Fortran::lower::defineCommonBlocks(
     finalizeCommonBlockDefinition(loc, converter, global, cmnBlkMems);
 }
 
+mlir::Value Fortran::lower::genCommonBlockMember(
+    Fortran::lower::AbstractConverter &converter, mlir::Location loc,
+    const Fortran::semantics::Symbol &sym, mlir::Value commonValue) {
+  fir::FirOpBuilder &builder = converter.getFirOpBuilder();
+
+  std::size_t byteOffset = sym.GetUltimate().offset();
+  mlir::IntegerType i8Ty = builder.getIntegerType(8);
+  mlir::Type i8Ptr = builder.getRefType(i8Ty);
+  mlir::Type seqTy = builder.getRefType(builder.getVarLenSeqTy(i8Ty));
+  mlir::Value base = builder.createConvert(loc, seqTy, commonValue);
+
+  mlir::Value offs =
+      builder.createIntegerConstant(loc, builder.getIndexType(), byteOffset);
+  mlir::Value varAddr = builder.create<fir::CoordinateOp>(
+      loc, i8Ptr, base, mlir::ValueRange{offs});
+  mlir::Type symType = converter.genType(sym);
+
+  return Fortran::semantics::FindEquivalenceSet(sym) != nullptr
+             ? castAliasToPointer(builder, loc, symType, varAddr)
+             : builder.createConvert(loc, builder.getRefType(symType), varAddr);
+}
+
 /// The COMMON block is a global structure. `var` will be at some offset
 /// within the COMMON block. Adds the address of `var` (COMMON + offset) to
 /// the symbol map.
@@ -1353,21 +1375,8 @@ static void instantiateCommon(Fortran::lower::AbstractConverter &converter,
 
     symMap.addSymbol(common, commonAddr);
   }
-  std::size_t byteOffset = varSym.GetUltimate().offset();
-  mlir::IntegerType i8Ty = builder.getIntegerType(8);
-  mlir::Type i8Ptr = builder.getRefType(i8Ty);
-  mlir::Type seqTy = builder.getRefType(builder.getVarLenSeqTy(i8Ty));
-  mlir::Value base = builder.createConvert(loc, seqTy, commonAddr);
-  mlir::Value offs =
-      builder.createIntegerConstant(loc, builder.getIndexType(), byteOffset);
-  auto varAddr = builder.create<fir::CoordinateOp>(loc, i8Ptr, base,
-                                                   mlir::ValueRange{offs});
-  mlir::Type symType = converter.genType(var.getSymbol());
-  mlir::Value local;
-  if (Fortran::semantics::FindEquivalenceSet(var.getSymbol()) != nullptr)
-    local = castAliasToPointer(builder, loc, symType, varAddr);
-  else
-    local = builder.createConvert(loc, builder.getRefType(symType), varAddr);
+
+  mlir::Value local = genCommonBlockMember(converter, loc, varSym, commonAddr);
   Fortran::lower::StatementContext stmtCtx;
   mapSymbolAttributes(converter, var, symMap, stmtCtx, local);
 }

flang/lib/Lower/OpenMP.cpp

@@ -1959,31 +1959,6 @@ static mlir::Operation *getCompareFromReductionOp(mlir::Operation *reductionOp,
   return nullptr;
 }
 
-/// The COMMON block is a global structure. \p commonValue is the base address
-/// of the COMMON block. As the offset from the symbol \p sym, generate the
-/// COMMON block member value (commonValue + offset) for the symbol.
-/// FIXME: Share the code with `instantiateCommon` in ConvertVariable.cpp.
-static mlir::Value
-genCommonBlockMember(Fortran::lower::AbstractConverter &converter,
-                     const Fortran::semantics::Symbol &sym,
-                     mlir::Value commonValue) {
-  fir::FirOpBuilder &firOpBuilder = converter.getFirOpBuilder();
-  mlir::Location currentLocation = converter.getCurrentLocation();
-  mlir::IntegerType i8Ty = firOpBuilder.getIntegerType(8);
-  mlir::Type i8Ptr = firOpBuilder.getRefType(i8Ty);
-  mlir::Type seqTy = firOpBuilder.getRefType(firOpBuilder.getVarLenSeqTy(i8Ty));
-  mlir::Value base =
-      firOpBuilder.createConvert(currentLocation, seqTy, commonValue);
-  std::size_t byteOffset = sym.GetUltimate().offset();
-  mlir::Value offs = firOpBuilder.createIntegerConstant(
-      currentLocation, firOpBuilder.getIndexType(), byteOffset);
-  mlir::Value varAddr = firOpBuilder.create<fir::CoordinateOp>(
-      currentLocation, i8Ptr, base, mlir::ValueRange{offs});
-  mlir::Type symType = converter.genType(sym);
-  return firOpBuilder.createConvert(currentLocation,
-                                    firOpBuilder.getRefType(symType), varAddr);
-}
-
 // Get the extended value for \p val by extracting additional variable
 // information from \p base.
 static fir::ExtendedValue getExtendedValue(fir::ExtendedValue base,
@@ -2049,8 +2024,8 @@ static void threadPrivatizeVars(Fortran::lower::AbstractConverter &converter,
         converter.bindSymbol(*common, commonThreadprivateValue);
         commonSyms.insert(common);
       }
-      symThreadprivateValue =
-          genCommonBlockMember(converter, *sym, commonThreadprivateValue);
+      symThreadprivateValue = Fortran::lower::genCommonBlockMember(
+          converter, currentLocation, *sym, commonThreadprivateValue);
     } else {
       symThreadprivateValue = genThreadprivateOp(*sym);
     }
@@ -3554,8 +3529,8 @@ void Fortran::lower::genThreadprivateOp(
             currentLocation, commonValue.getType(), commonValue);
     converter.bindSymbol(*common, commonThreadprivateValue);
     // Generate the threadprivate value for the common block member.
-    symThreadprivateValue =
-        genCommonBlockMember(converter, sym, commonThreadprivateValue);
+    symThreadprivateValue = genCommonBlockMember(converter, currentLocation,
+                                                 sym, commonThreadprivateValue);
   } else if (!var.isGlobal()) {
     // Non-global variable which can be in threadprivate directive must be one
     // variable in main program, and it has implicit SAVE attribute. Take it as