[flang] Fix attribute printing for fir.global op (#81197)

The custom printer for `fir.global` was eluding all the attributes
present on the op when printing the attribute dictionary. So any
attribute that is not part of the pretty printing was therefore
discarded.
This patch fix the printer and also make use of the getters for the
attribute names when they are hardcoded.

Author: clementval

flang/lib/Optimizer/Dialect/FIROps.cpp

@@ -1348,12 +1348,12 @@ mlir::ParseResult fir::GlobalOp::parse(mlir::OpAsmParser &parser,
   if (parser.parseOptionalAttrDict(result.attributes))
     return mlir::failure();
 
-  if (succeeded(parser.parseOptionalKeyword("constant"))) {
+  if (succeeded(parser.parseOptionalKeyword(getConstantAttrNameStr()))) {
     // if "constant" keyword then mark this as a constant, not a variable
-    result.addAttribute("constant", builder.getUnitAttr());
+    result.addAttribute(getConstantAttrNameStr(), builder.getUnitAttr());
   }
 
-  if (succeeded(parser.parseOptionalKeyword("target")))
+  if (succeeded(parser.parseOptionalKeyword(getTargetAttrNameStr())))
     result.addAttribute(getTargetAttrNameStr(), builder.getUnitAttr());
 
   mlir::Type globalType;
@@ -1382,11 +1382,16 @@ void fir::GlobalOp::print(mlir::OpAsmPrinter &p) {
   p.printAttributeWithoutType(getSymrefAttr());
   if (auto val = getValueOrNull())
     p << '(' << val << ')';
-  p.printOptionalAttrDict((*this)->getAttrs(), (*this).getAttributeNames());
-  if (getOperation()->getAttr(fir::GlobalOp::getConstantAttrNameStr()))
-    p << " constant";
+  // Print all other attributes that are not pretty printed here.
+  p.printOptionalAttrDict((*this)->getAttrs(), /*elideAttrs=*/{
+                              getSymNameAttrName(), getSymrefAttrName(),
+                              getTypeAttrName(), getConstantAttrName(),
+                              getTargetAttrName(), getLinkNameAttrName(),
+                              getInitValAttrName()});
+  if (getOperation()->getAttr(getConstantAttrName()))
+    p << " " << getConstantAttrNameStr();
   if (getOperation()->getAttr(getTargetAttrName()))
-    p << " target";
+    p << " " << getTargetAttrNameStr();
   p << " : ";
   p.printType(getType());
   if (hasInitializationBody()) {

flang/test/Fir/fir-ops.fir

@@ -893,3 +893,10 @@ func.func @test_box_typecode(%a: !fir.class<none>) {
 // CHECK-LABEL: func.func @test_box_typecode(
 // CHECK-SAME: %[[A:.*]]: !fir.class<none>)
 // CHECK: %{{.*}} = fir.box_typecode %[[A]] : (!fir.class<none>) -> i32
+
+fir.global @t1 {keep_my_attr = "data"} : i32 {
+ %1 = arith.constant 0 : i32
+  fir.has_value %1 : i32
+}
+
+// CHECK-LABEL: fir.global @t1 {keep_my_attr = "data"} : i32