[llvm-branch-commits] [flang] [MLIR][OpenMP] Add Lowering support for OpenMP Declare Mapper directive (PR #117046)

[Tom Eccles via llvm-branch-commits]

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@@ -2612,7 +2612,54 @@ static void
 genOMP(lower::AbstractConverter &converter, lower::SymMap &symTable,
        semantics::SemanticsContext &semaCtx, lower::pft::Evaluation &eval,
        const parser::OpenMPDeclareMapperConstruct &declareMapperConstruct) {
-  TODO(converter.getCurrentLocation(), "OpenMPDeclareMapperConstruct");
+  mlir::Location loc = converter.genLocation(declareMapperConstruct.source);
+  fir::FirOpBuilder &firOpBuilder = converter.getFirOpBuilder();
+  lower::StatementContext stmtCtx;
+  const auto &spec =
+      std::get<parser::OmpDeclareMapperSpecifier>(declareMapperConstruct.t);
+  const auto &mapperName{std::get<std::optional<parser::Name>>(spec.t)};
+  const auto &varType{std::get<parser::TypeSpec>(spec.t)};
+  const auto &varName{std::get<parser::Name>(spec.t)};
+  assert(varType.declTypeSpec->category() ==
+             semantics::DeclTypeSpec::Category::TypeDerived &&
+         "Expected derived type");
+
+  std::string mapperNameStr;
+  if (mapperName.has_value()) {
+    mapperNameStr = mapperName->ToString();
+    mapperNameStr =
+        converter.mangleName(mapperNameStr, mapperName->symbol->owner());
+  } else {
+    mapperNameStr =
+        varType.declTypeSpec->derivedTypeSpec().name().ToString() + ".default";
+    mapperNameStr = converter.mangleName(
+        mapperNameStr, *varType.declTypeSpec->derivedTypeSpec().GetScope());
+  }
+
+  // Save insert point just after the DeclMapperOp.
+  mlir::OpBuilder::InsertPoint insPt = firOpBuilder.saveInsertionPoint();
+
+  firOpBuilder.setInsertionPointToStart(converter.getModuleOp().getBody());
+  auto mlirType = converter.genType(varType.declTypeSpec->derivedTypeSpec());
+  auto declMapperOp = firOpBuilder.create<mlir::omp::DeclareMapperOp>(
+      loc, mapperNameStr, mlirType);
+  converter.getMLIRSymbolTable()->insert(declMapperOp);
+  auto &region = declMapperOp.getRegion();
+  firOpBuilder.createBlock(&region);
+  auto varVal = region.addArgument(firOpBuilder.getRefType(mlirType), loc);
+  converter.bindSymbol(*varName.symbol, varVal);
+
+  // Populate the declareMapper region with the map information.
+  mlir::omp::DeclareMapperInfoOperands clauseOps;
+  const auto *clauseList{
+      parser::Unwrap<parser::OmpClauseList>(declareMapperConstruct.t)};
+  List<Clause> clauses = makeClauses(*clauseList, semaCtx);
+  ClauseProcessor cp(converter, semaCtx, clauses);
+  cp.processMap(loc, stmtCtx, clauseOps);
+  firOpBuilder.create<mlir::omp::DeclareMapperInfoOp>(loc, clauseOps.mapVars);
+
+  // Restore the insert point to just after the DeclareMapperOp.
+  firOpBuilder.restoreInsertionPoint(insPt);
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tblah wrote:

With my change to use the insertion point guard above
```suggestion
```

https://github.com/llvm/llvm-project/pull/117046