[Flang] Enable lowering of CONVERT specifier in OPEN statements

[jpenix-quic]

Summary

The runtime function is implemented and the specifier is
handled, but it seems lowering was never added, so enable
lowering this feature.

[peixin]

flang/test/Lower/io-statement-open-options.f90

10

Can you add the IR check for "BIG_ENDIAN" argument specifically since this patch is supporting that?

[jpenix-quic]

Add IR checks to make sure that the BIG_ENDIAN string and string length are correctly set and passed into SetConvert.

[jpenix-quic]

flang/test/Lower/io-statement-open-options.f90

10

Added!

[peixin]

LGTM. Please wait for one more approval. @jeanPerier

[peixin]

@jeanPerier @clementval Can this be merged now? This will help test -fconvert= option in https://reviews.llvm.org/D130513.

[clementval]

LG

flang/lib/Lower/IO.cpp

static constexpr std::tuple<
     mkIOKey(OutputComplex64), mkIOKey(InputComplex64), mkIOKey(OutputAscii),
     mkIOKey(InputAscii), mkIOKey(OutputLogical), mkIOKey(InputLogical),
     mkIOKey(SetAccess), mkIOKey(SetAction), mkIOKey(SetAsynchronous),
     mkIOKey(SetCarriagecontrol), mkIOKey(SetEncoding), mkIOKey(SetForm),
     mkIOKey(SetPosition), mkIOKey(SetRecl), mkIOKey(SetStatus),
     mkIOKey(SetFile), mkIOKey(GetNewUnit), mkIOKey(GetSize),
     mkIOKey(GetIoLength), mkIOKey(GetIoMsg), mkIOKey(InquireCharacter),
     mkIOKey(InquireLogical), mkIOKey(InquirePendingId),
-    mkIOKey(InquireInteger64), mkIOKey(EndIoStatement)>
+    mkIOKey(InquireInteger64), mkIOKey(EndIoStatement), mkIOKey(SetConvert)>
     newIOTable;
 } // namespace Fortran::lower
 
 namespace {
 /// IO statements may require exceptional condition handling.  A statement that
 /// encounters an exceptional condition may branch to a label given on an ERR
 /// (error), END (end-of-file), or EOR (end-of-record) specifier.  An IOSTAT
 /// specifier variable may be set to a value that indicates some condition,
case Fortran::parser::ConnectSpec::CharExpr::Kind::Round:
     break;
   case Fortran::parser::ConnectSpec::CharExpr::Kind::Sign:
     ioFunc = getIORuntimeFunc<mkIOKey(SetSign)>(loc, builder);
     break;
   case Fortran::parser::ConnectSpec::CharExpr::Kind::Carriagecontrol:
     ioFunc = getIORuntimeFunc<mkIOKey(SetCarriagecontrol)>(loc, builder);
     break;
   case Fortran::parser::ConnectSpec::CharExpr::Kind::Convert:
-    TODO(loc, "CONVERT not part of the runtime::io interface");
+    ioFunc = getIORuntimeFunc<mkIOKey(SetConvert)>(loc, builder);
+    break;
   case Fortran::parser::ConnectSpec::CharExpr::Kind::Dispose:
     TODO(loc, "DISPOSE not part of the runtime::io interface");
   }
   Fortran::lower::StatementContext localStatementCtx;
   mlir::FunctionType ioFuncTy = ioFunc.getFunctionType();
   std::tuple<mlir::Value, mlir::Value, mlir::Value> tup =
       lowerStringLit(converter, loc, localStatementCtx,
                      std::get<Fortran::parser::ScalarDefaultCharExpr>(spec.t),

flang/test/Lower/io-statement-open-options.f90

+! Test lowering of OPEN statment options
+! RUN: bbc %s -emit-fir -o - | FileCheck %s
+
+! CHECK-LABEL: func.func @_QPtest_convert_specifier(
+subroutine test_convert_specifier(unit)
+  integer :: unit
+  ! CHECK: %[[cookie:.*]] = fir.call @_FortranAioBeginOpenUnit(%{{.*}}, %{{.*}}, %{{.*}}) : (i32, !fir.ref<i8>, i32) -> !fir.ref<i8>
+  ! CHECK: %{{.*}} = fir.call @_FortranAioSetConvert(%[[cookie]], %{{.*}}, %{{.*}}) : (!fir.ref<i8>, !fir.ref<i8>, i64) -> i1
+  ! CHECK: %{{.*}} = fir.call @_FortranAioEndIoStatement(%[[cookie]]) : (!fir.ref<i8>) -> i32
+  open(unit, form="UNFORMATTED", convert="BIG_ENDIAN")
+  close(unit)
+end subroutine