[flang] Fix shared library builds for lib/Lower.

[DavidTruby]

Summary

This adds missing definitions for functions in the Lower directory
that were causing failures in shared library builds.
The definitions for these are taken from the fir-dev branch on github.

flang/lib/Lower/CMakeLists.txt

 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-error -Wno-unused-parameter")
 get_property(dialect_libs GLOBAL PROPERTY MLIR_DIALECT_LIBS)
 
 add_flang_library(FortranLower
   CharacterExpr.cpp
   CharacterRuntime.cpp
   Coarray.cpp
   ComplexExpr.cpp
   ConvertType.cpp
+  ConvertExpr.cpp
   DoLoopHelper.cpp
   FIRBuilder.cpp
   IntrinsicCall.cpp
   IO.cpp
   Mangler.cpp
   OpenMP.cpp
   PFTBuilder.cpp
 

flang/lib/Lower/ConvertExpr.cpp

+//===-- ConvertExpr.cpp ---------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "flang/Common/idioms.h"
+#include "flang/Lower/IntrinsicCall.h"
+#include "flang/Lower/Support/BoxValue.h"
+
+mlir::Value fir::getBase(const fir::ExtendedValue &ex) {
+  return std::visit(Fortran::common::visitors{
+                        [](const fir::UnboxedValue &x) { return x; },
+                        [](const auto &x) { return x.getAddr(); },
+                    },
+                    ex.box);
+}
+
+llvm::raw_ostream &fir::operator<<(llvm::raw_ostream &os,
+                                   const fir::CharBoxValue &box) {
+  os << "boxchar { addr: " << box.getAddr() << ", len: " << box.getLen()
+     << " }";
+  return os;
+}
+
+llvm::raw_ostream &fir::operator<<(llvm::raw_ostream &os,
+                                   const fir::ArrayBoxValue &box) {
+  os << "boxarray { addr: " << box.getAddr();
+  if (box.getLBounds().size()) {
+    os << ", lbounds: [";
+    llvm::interleaveComma(box.getLBounds(), os);
+    os << "]";
+  } else {
+    os << ", lbounds: all-ones";
+  }
+  os << ", shape: [";
+  llvm::interleaveComma(box.getExtents(), os);
+  os << "]}";
+  return os;
+}
+
+llvm::raw_ostream &fir::operator<<(llvm::raw_ostream &os,
+                                   const fir::CharArrayBoxValue &box) {
+  os << "boxchararray { addr: " << box.getAddr() << ", len : " << box.getLen();
+  if (box.getLBounds().size()) {
+    os << ", lbounds: [";
+    llvm::interleaveComma(box.getLBounds(), os);
+    os << "]";
+  } else {
+    os << " lbounds: all-ones";
+  }
+  os << ", shape: [";
+  llvm::interleaveComma(box.getExtents(), os);
+  os << "]}";
+  return os;
+}
+
+llvm::raw_ostream &fir::operator<<(llvm::raw_ostream &os,
+                                   const fir::BoxValue &box) {
+  os << "box { addr: " << box.getAddr();
+  if (box.getLen())
+    os << ", size: " << box.getLen();
+  if (box.params.size()) {
+    os << ", type params: [";
+    llvm::interleaveComma(box.params, os);
+    os << "]";
+  }
+  if (box.getLBounds().size()) {
+    os << ", lbounds: [";
+    llvm::interleaveComma(box.getLBounds(), os);
+    os << "]";
+  }
+  if (box.getExtents().size()) {
+    os << ", shape: [";
+    llvm::interleaveComma(box.getExtents(), os);
+    os << "]";
+  }
+  os << "}";
+  return os;
+}
+
+llvm::raw_ostream &fir::operator<<(llvm::raw_ostream &os,
+                                   const fir::ProcBoxValue &box) {
+  os << "boxproc: { addr: " << box.getAddr() << ", context: " << box.hostContext
+     << "}";
+  return os;
+}
+
+llvm::raw_ostream &fir::operator<<(llvm::raw_ostream &os,
+                                   const fir::ExtendedValue &ex) {
+  std::visit([&](const auto &value) { os << value; }, ex.box);
+  return os;
+}

flang/lib/Optimizer/Dialect/FIROps.cpp

 mlir::OpFoldResult fir::SubfOp::fold(llvm::ArrayRef<mlir::Attribute> opnds) {
   return mlir::constFoldBinaryOp<FloatAttr>(
       opnds, [](APFloat a, APFloat b) { return a - b; });
 }
 
 //===----------------------------------------------------------------------===//
 // WhereOp
 //===----------------------------------------------------------------------===//
-
 void fir::WhereOp::build(mlir::OpBuilder &builder, OperationState &result,
                          mlir::Value cond, bool withElseRegion) {
+  build(builder, result, llvm::None, cond, withElseRegion);
+}
+
+void fir::WhereOp::build(mlir::OpBuilder &builder, OperationState &result,
+                         mlir::TypeRange resultTypes, mlir::Value cond,
+                         bool withElseRegion) {
   result.addOperands(cond);
+  result.addTypes(resultTypes);
+
   mlir::Region *thenRegion = result.addRegion();
-  mlir::Region *elseRegion = result.addRegion();
+  thenRegion->push_back(new mlir::Block());
+  if (resultTypes.empty())
     WhereOp::ensureTerminator(*thenRegion, builder, result.location);
-  if (withElseRegion)
+
+  mlir::Region *elseRegion = result.addRegion();
+  if (withElseRegion) {
+    elseRegion->push_back(new mlir::Block());
+    if (resultTypes.empty())
       WhereOp::ensureTerminator(*elseRegion, builder, result.location);
   }
+}
 
 static mlir::ParseResult parseWhereOp(OpAsmParser &parser,
                                       OperationState &result) {
   result.regions.reserve(2);
   mlir::Region *thenRegion = result.addRegion();
   mlir::Region *elseRegion = result.addRegion();
 
   auto &builder = parser.getBuilder();