qapi-visit: Kill unused visit_end_union()

The generated code can call visit_end_union() without having called
visit_start_union(). Example:

if (!*obj) {
goto out_obj;
}
visit_type_CpuInfoBase_fields(v, (CpuInfoBase **)obj, &err);
if (err) {
goto out_obj; // if we go from here...
}
if (!visit_start_union(v, !!(*obj)->u.data, &err) || err) {
goto out_obj;
}
switch ((*obj)->arch) {
[...]
}
out_obj:
// ... then *obj is true, and ...
error_propagate(errp, err);
err = NULL;
if (*obj) {
// we end up here
visit_end_union(v, !!(*obj)->u.data, &err);
}
error_propagate(errp, err);

Harmless only because no visitor implements end_union(). Clean it up
anyway, by deleting the function as useless.

Messed up since we have visit_end_union (commit cee2ded).

Backports commit 7c91aabd8964cfdf637f302c579c95401f21ce92 from qemu

msvc/unicorn/qapi-visit.c

@@ -35,12 +35,18 @@ void visit_type_DummyForceArrays(Visitor *v, DummyForceArrays **obj, const char
 
     visit_start_struct(v, (void **)obj, "DummyForceArrays", name, sizeof(DummyForceArrays), &err);
 
-    if (!err) {
+    if (err) {
-        if (*obj) {
+        goto out;
-            visit_type_DummyForceArrays_fields(v, obj, errp);
-        }
-        visit_end_struct(v, &err);
     }
+    if (!*obj) {
+        goto out_obj;
+    }
+    visit_type_DummyForceArrays_fields(v, obj, &err);
+    error_propagate(errp, err);
+    err = NULL;
+out_obj:
+    visit_end_struct(v, &err);
+out:
     error_propagate(errp, err);
 }
 
@@ -87,12 +93,18 @@ void visit_type_X86CPUFeatureWordInfo(Visitor *v, X86CPUFeatureWordInfo **obj, c
 
     visit_start_struct(v, (void **)obj, "X86CPUFeatureWordInfo", name, sizeof(X86CPUFeatureWordInfo), &err);
 
-    if (!err) {
+    if (err) {
-        if (*obj) {
+        goto out;
-            visit_type_X86CPUFeatureWordInfo_fields(v, obj, errp);
-        }
-        visit_end_struct(v, &err);
     }
+    if (!*obj) {
+        goto out_obj;
+    }
+    visit_type_X86CPUFeatureWordInfo_fields(v, obj, &err);
+    error_propagate(errp, err);
+    err = NULL;
+out_obj:
+    visit_end_struct(v, &err);
+out:
     error_propagate(errp, err);
 }
 

qemu/include/qapi/visitor-impl.h

@@ -62,7 +62,6 @@ struct Visitor
     void (*type_int16)(Visitor *v, int16_t *obj, const char *name, Error **errp);
     void (*type_int32)(Visitor *v, int32_t *obj, const char *name, Error **errp);
     bool (*start_union)(Visitor *v, bool data_present, Error **errp);
-    void (*end_union)(Visitor *v, bool data_present, Error **errp);
 };
 
 void input_type_enum(Visitor *v, int *obj, const char * const strings[],

qemu/include/qapi/visitor.h

@@ -70,6 +70,5 @@ void visit_type_str(Visitor *v, char **obj, const char *name, Error **errp);
 void visit_type_number(Visitor *v, double *obj, const char *name, Error **errp);
 void visit_type_any(Visitor *v, QObject **obj, const char *name, Error **errp);
 bool visit_start_union(Visitor *v, bool data_present, Error **errp);
-void visit_end_union(Visitor *v, bool data_present, Error **errp);
 
 #endif

qemu/qapi/qapi-visit-core.c

@@ -1,8 +1,10 @@
 /*
  * Core Definitions for QAPI Visitor Classes
  *
+ * Copyright (C) 2012-2016 Red Hat, Inc.
  * Copyright IBM, Corp. 2011
  *
+ *
  * Authors:
  *  Anthony Liguori   <aliguori@us.ibm.com>
  *
@@ -67,13 +69,6 @@ bool visit_start_union(Visitor *v, bool data_present, Error **errp)
     return true;
 }
 
-void visit_end_union(Visitor *v, bool data_present, Error **errp)
-{
-    if (v->end_union) {
-        v->end_union(v, data_present, errp);
-    }
-}
-
 bool visit_optional(Visitor *v, bool *present, const char *name)
 {
     if (v->optional) {

qemu/scripts/qapi-visit.py

@@ -316,11 +316,6 @@ void visit_type_%(c_name)s(Visitor *v, %(c_name)s **obj, const char *name, Error
         abort();
     }
 out_obj:
-    error_propagate(errp, err);
-    err = NULL;
-    if (*obj) {
-        visit_end_union(v, !!(*obj)->u.data, &err);
-    }
     error_propagate(errp, err);
     err = NULL;
     visit_end_struct(v, &err);