* fixed returning results from functions that have a zero-sized result

    (e.g. an empty record): return an "undefined" instance of the result
    type (since it's empty, its contents are irrelevant). Before, we
    returned "void", but that means returning nothing rather than returning
    something empty (part of fixing test/tnoext4 for llvm)

git-svn-id: trunk@34119 -

compiler/llvm/aasmllvm.pas

@@ -71,6 +71,9 @@ interface
         { dst = bitcast size undef to size }
         constructor op_reg_size_undef(op: tllvmop; dst: tregister; size: tdef);
 
+        { return size undef }
+        constructor op_size_undef(op: tllvmop; size: tdef);
+
         { e.g. dst = bitcast fromsize src to tosize }
         constructor op_reg_size_ref_size(op:tllvmop;dst:tregister;fromsize:tdef;const src:treference;tosize:tdef);
         { e.g. store fromsize src, ptrsize toref}
@@ -762,6 +765,14 @@ uses
         loaddef(3,size);
       end;
 
+    constructor taillvm.op_size_undef(op: tllvmop; size: tdef);
+      begin
+        create_llvm(op);
+        ops:=2;
+        loaddef(0,size);
+        loadundef(1);
+      end;
+
 
     constructor taillvm.op_reg_size_ref_size(op: tllvmop; dst: tregister; fromsize: tdef; const src: treference; tosize: tdef);
       begin

compiler/llvm/hlcgllvm.pas

@@ -1277,6 +1277,12 @@ implementation
                       end;
                    end;
                 list.concat(taillvm.op_size_reg(la_ret,retdef,retreg))
+              end;
+            LOC_VOID:
+              begin
+                { zero-sized records: return an undefined zero-sized record of
+                  the correct type }
+                list.concat(taillvm.op_size_undef(la_ret,retdef));
               end
             else
               { todo: complex returns }