Cxx: use a trashbox for deleteing tokens allocated for anonymous para…

…meters

Partially close #3372.

The original code assumed tokens allocated in
cxxParserTokenChainLooksLikeFunctionParameterList() for tagging
anonymous parameters were deleted on its caller side
(cxxParserEmitFunctionParameterTags()).

However, in some conditions, cxxParserEmitFunctionParameterTags() are
not called. As a result, the allocated tokens are not deleted.

To avoid the memory leaking, the deletion cannot depend on
cxxParserEmitFunctionParameterTags(). This change uses per-parsing
trashbox for deleting the anonymous tokens. The objects linked to
the trashbox are destroyed at the end of parsing the current input
file.

Signed-off-by: Masatake YAMATO <yamato@redhat.com>

Units/parser-c.r/anonymous-param-in-broken-paramlist.d/README

@@ -0,0 +1 @@
+This is a test case for detecting memory leaking.

Units/parser-c.r/anonymous-param-in-broken-paramlist.d/args.ctags

@@ -0,0 +1,2 @@
+--kinds-C=+z
+--extras=+{anonymous}

Units/parser-c.r/anonymous-param-in-broken-paramlist.d/input-0.c

@@ -0,0 +1,16 @@
+/* https://gitlab.gnome.org/GNOME/glib/-/blob/main/gio/gdummyproxyresolver.c */
+G_DEFINE_TYPE_WITH_CODE (GDummyProxyResolver, g_dummy_proxy_resolver, G_TYPE_OBJECT,
+			 G_IMPLEMENT_INTERFACE (G_TYPE_PROXY_RESOLVER,
+						g_dummy_proxy_resolver_iface_init)
+			 _g_io_modules_ensure_extension_points_registered ();
+			 g_io_extension_point_implement (G_PROXY_RESOLVER_EXTENSION_POINT_NAME,
+							 g_define_type_id,
+							 "dummy",
+							 -100))
+
+static void
+g_dummy_proxy_resolver_finalize (GObject *object)
+{
+  /* must chain up */
+  G_OBJECT_CLASS (g_dummy_proxy_resolver_parent_class)->finalize (object);
+}

Units/parser-c.r/anonymous-param-in-broken-paramlist.d/input-1.c

@@ -0,0 +1 @@
+G (f () g ()) h (void) {

Units/parser-c.r/anonymous-param-in-broken-paramlist.d/input.c

@@ -0,0 +1 @@
+f(a,){

parsers/cxx/cxx_parser_function.c

@@ -1889,6 +1889,8 @@ void cxxParserEmitFunctionParameterTags(CXXTypedVariableSet * pInfo)
 
 		if(pTypeName)
 		{
+			if (pInfo->uAnonymous & (0x1u << i))
+				PARSER_TRASH_BOX_TAKE_BACK (pInfo->aIdentifiers[i]);
 			cxxTokenDestroy(pInfo->aIdentifiers[i]);
 			cxxTokenDestroy(pTypeName);
 		}
@@ -2180,6 +2182,7 @@ bool cxxParserTokenChainLooksLikeFunctionParameterList(
 						pIdentifier->iLineNumber = t->pPrev->iLineNumber;
 						pIdentifier->oFilePosition = t->pPrev->oFilePosition;
 						pParamInfo->uAnonymous |= (0x1u << pParamInfo->uCount);
+						PARSER_TRASH_BOX (pIdentifier, cxxTokenDestroy);
 					}
 					pParamInfo->aIdentifiers[pParamInfo->uCount] = pIdentifier;
 					pParamInfo->uCount++;
@@ -2233,7 +2236,7 @@ bool cxxParserTokenChainLooksLikeFunctionParameterList(
 			pParamInfo->uCount++;
 
 			PARSER_TRASH_BOX (pFakeStart, cxxTokenDestroy);
-			/* pFakeId may be destroyed via pParamInfo->aIdentifiers[i]. */
+			PARSER_TRASH_BOX (pFakeId, cxxTokenDestroy);
 		}
 
 		if(cxxTokenTypeIs(t,CXXTokenTypeClosingParenthesis))