[Qemu-devel] [RFC PATCH 06/11] scripts/decodetree: Allow empty specifications

["Philippe Mathieu-Daudé" <f4bug@amsat.org>]

Starting with empty specifications allow to write stubs/templates,
useful when testing/rebasing.

This fixes:

  decode.inc.c: In function ‘decode’:
  decode.inc.c:9:7: error: unused variable ‘u’ [-Werror=unused-variable]
     } u;
       ^

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 scripts/decodetree.py | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/scripts/decodetree.py b/scripts/decodetree.py
index 08aa52d544..41ed67132d 100755
--- a/scripts/decodetree.py
+++ b/scripts/decodetree.py
@@ -1060,12 +1060,13 @@ def main():
     output(decode_scope, 'bool ', decode_function,
            '(DisasContext *ctx, ', insntype, ' insn)\n{\n')
 
-    i4 = str_indent(4)
-    output(i4, 'union {\n')
-    for n in sorted(arguments.keys()):
-        f = arguments[n]
-        output(i4, i4, f.struct_name(), ' f_', f.name, ';\n')
-    output(i4, '} u;\n\n')
+    if arguments:
+        i4 = str_indent(4)
+        output(i4, 'union {\n')
+        for n in sorted(arguments.keys()):
+            f = arguments[n]
+            output(i4, i4, f.struct_name(), ' f_', f.name, ';\n')
+        output(i4, '} u;\n\n')
 
     t.output_code(4, False, 0, 0)
 
-- 
2.17.2