[flang] Support legacy usage of 'A' edit descriptors for integer & real

The 'A' edit descriptor once served as a form of raw I/O of bytes
to/from variables that weren't of type CHARACTER (which itself
didn't exist until F'77).  This usage was especially common for
output of numeric variables that had been initialized with Hollerith.

Differential Revision: https://reviews.llvm.org/D112346

Author: klausler

flang/runtime/edit-input.cpp

@@ -83,6 +83,9 @@ bool EditIntegerInput(
     return EditBOZInput(io, edit, n, 8, kind << 3);
   case 'Z':
     return EditBOZInput(io, edit, n, 16, kind << 3);
+  case 'A': // legacy extension
+    return EditDefaultCharacterInput(
+        io, edit, reinterpret_cast<char *>(n), kind);
   default:
     io.GetIoErrorHandler().SignalError(IostatErrorInFormat,
         "Data edit descriptor '%c' may not be used with an INTEGER data item",
@@ -323,6 +326,9 @@ bool EditRealInput(IoStatementState &io, const DataEdit &edit, void *n) {
   case 'Z':
     return EditBOZInput(
         io, edit, n, 16, common::BitsForBinaryPrecision(binaryPrecision));
+  case 'A': // legacy extension
+    return EditDefaultCharacterInput(
+        io, edit, reinterpret_cast<char *>(n), KIND);
   default:
     io.GetIoErrorHandler().SignalError(IostatErrorInFormat,
         "Data edit descriptor '%c' may not be used for REAL input",

flang/runtime/edit-output.cpp

@@ -52,6 +52,9 @@ bool EditIntegerOutput(IoStatementState &io, const DataEdit &edit,
       *--p = digit >= 10 ? 'A' + (digit - 10) : '0' + digit;
     }
     break;
+  case 'A': // legacy extension
+    return EditDefaultCharacterOutput(
+        io, edit, reinterpret_cast<char *>(&n), sizeof n);
   default:
     io.GetIoErrorHandler().Crash(
         "Data edit descriptor '%c' may not be used with an INTEGER data item",
@@ -402,6 +405,9 @@ template <int KIND> bool RealOutputEditing<KIND>::Edit(const DataEdit &edit) {
             decimal::BinaryFloatingPointNumber<binaryPrecision>{x_}.raw()));
   case 'G':
     return Edit(EditForGOutput(edit));
+  case 'A': // legacy extension
+    return EditDefaultCharacterOutput(
+        io_, edit, reinterpret_cast<char *>(&x_), sizeof x_);
   default:
     if (edit.IsListDirected()) {
       return EditListDirectedOutput(edit);

flang/unittests/Runtime/RuntimeCrashTest.cpp

@@ -57,8 +57,8 @@ TEST(TestIOCrash, FormatDescriptorWriteMismatchTest) {
   static const char *format{"(A4)"};
   auto *cookie{IONAME(BeginInternalFormattedOutput)(
       buffer, bufferSize, format, std::strlen(format))};
-  ASSERT_DEATH(IONAME(OutputInteger64)(cookie, 0xfeedface),
-      "Data edit descriptor 'A' may not be used with an INTEGER data item");
+  ASSERT_DEATH(IONAME(OutputLogical)(cookie, true),
+      "Data edit descriptor 'A' may not be used with a LOGICAL data item");
 }
 
 TEST(TestIOCrash, InvalidFormatCharacterTest) {