Minor refcounting fixes

from_cpython/Include/sysmodule.h

@@ -9,7 +9,7 @@ extern "C" {
 #endif
 
 // Pyston change: changed most of these to const char*
-PyAPI_FUNC(PyObject *) PySys_GetObject(const char *) PYSTON_NOEXCEPT;
+PyAPI_FUNC(BORROWED(PyObject *)) PySys_GetObject(const char *) PYSTON_NOEXCEPT;
 PyAPI_FUNC(int) PySys_SetObject(const char *, PyObject *) PYSTON_NOEXCEPT;
 PyAPI_FUNC(FILE *) PySys_GetFile(char *, FILE *) PYSTON_NOEXCEPT;
 PyAPI_FUNC(void) PySys_SetArgv(int, char **) PYSTON_NOEXCEPT;

src/codegen/unwinding.cpp

@@ -785,6 +785,7 @@ Box* getGlobals() {
     auto it = getTopPythonFrame();
     if (!it)
         return NULL;
+    RELEASE_ASSERT(0, "check refcounting");
     return it->getGlobals();
 }
 

src/runtime/builtin_modules/sys.cpp

@@ -87,7 +87,9 @@ BoxedDict* getSysModulesDict() {
 
 BoxedList* getSysPath() {
     // Unlike sys.modules, CPython handles sys.path by fetching it each time:
-    Box* _sys_path = sys_module->getattr(internStringMortal("path"));
+    auto path_str = getStaticString("path");
+
+    Box* _sys_path = sys_module->getattr(path_str);
     assert(_sys_path);
 
     if (_sys_path->cls != list_cls) {
@@ -99,7 +101,8 @@ BoxedList* getSysPath() {
 }
 
 Box* getSysStdout() {
-    Box* sys_stdout = sys_module->getattr(internStringMortal("stdout"));
+    auto stdout_str = getStaticString("stdout");
+    Box* sys_stdout = sys_module->getattr(stdout_str);
     RELEASE_ASSERT(sys_stdout, "lost sys.stdout??");
     return sys_stdout;
 }
@@ -137,10 +140,10 @@ Box* sysGetRecursionLimit() {
 extern "C" int PySys_SetObject(const char* name, PyObject* v) noexcept {
     try {
         if (!v) {
-            if (sys_module->getattr(internStringMortal(name)))
-                sys_module->delattr(internStringMortal(name), NULL);
+            if (sys_module->getattr(autoDecref(internStringMortal(name))))
+                sys_module->delattr(autoDecref(internStringMortal(name)), NULL);
         } else
-            sys_module->setattr(internStringMortal(name), v, NULL);
+            sys_module->setattr(autoDecref(internStringMortal(name)), v, NULL);
     } catch (ExcInfo e) {
         abort();
     }
@@ -148,7 +151,7 @@ extern "C" int PySys_SetObject(const char* name, PyObject* v) noexcept {
 }
 
 extern "C" PyObject* PySys_GetObject(const char* name) noexcept {
-    return sys_module->getattr(internStringMortal(name));
+    return sys_module->getattr(autoDecref(internStringMortal(name)));
 }
 
 extern "C" FILE* PySys_GetFile(char* name, FILE* def) noexcept {

src/runtime/exceptions.cpp

@@ -232,6 +232,7 @@ void raiseExcHelper(BoxedClass* cls, const char* msg, ...) {
 
         BoxedString* message = boxString(buf);
         Box* exc_obj = runtimeCall(cls, ArgPassSpec(1), message, NULL, NULL, NULL, NULL);
+        Py_DECREF(message);
         raiseExc(exc_obj);
     } else {
         Box* exc_obj = runtimeCall(cls, ArgPassSpec(0), NULL, NULL, NULL, NULL, NULL);

src/runtime/import.cpp

@@ -428,7 +428,7 @@ static Box* importSub(const std::string& name, BoxedString* full_name, Box* pare
         return module;
     }
 
-    return None;
+    return incref(None);
 }
 
 static void markMiss(std::string& name) {
@@ -474,6 +474,7 @@ static bool loadNext(Box* mod, Box* altmod, std::string& name, std::string& buf,
 
     result = importSub(subname, autoDecref(boxString(buf)), mod);
     if (result == None && altmod != mod) {
+        Py_DECREF(result);
         /* Here, altmod must be None and mod must not be None */
         result = importSub(subname, autoDecref(boxString(subname)), altmod);
         if (result != NULL && result != None) {
@@ -485,8 +486,10 @@ static bool loadNext(Box* mod, Box* altmod, std::string& name, std::string& buf,
     if (result == NULL)
         throwCAPIException();
 
-    if (result == None)
+    if (result == None) {
+        Py_DECREF(result);
         raiseExcHelper(ImportError, "No module named %.200s", local_name.c_str());
+    }
 
     *rtn = result;
     return call_again;
@@ -517,12 +520,16 @@ Box* importModuleLevel(llvm::StringRef name, Box* globals, Box* from_imports, in
     while (again) {
         Box* next;
         again = loadNext(tail, tail, _name, buf, &next);
+        Py_DECREF(tail);
         if (next == NULL) {
+            Py_DECREF(head);
             return NULL;
         }
         tail = next;
     }
     if (tail == None) {
+        Py_DECREF(tail);
+        Py_DECREF(head);
         /* If tail is Py_None, both get_parent and load_next found
            an empty module name: someone called __import__("") or
            doctored faulty bytecode */
@@ -707,7 +714,7 @@ Box* nullImporterFindModule(Box* self, Box* fullname, Box* path) {
 }
 
 extern "C" Box* import(int level, Box* from_imports, llvm::StringRef module_name) {
-    return importModuleLevel(module_name, getGlobals(), from_imports, level);
+    return importModuleLevel(module_name, autoDecref<Box, true>(getGlobals()), from_imports, level);
 }
 
 Box* impFindModule(Box* _name, BoxedList* path) {

src/runtime/objmodel.cpp

@@ -3700,7 +3700,7 @@ void rearrangeArgumentsInternal(ParamReceiveSpec paramspec, const ParamNames* pa
                        (paramspec.num_args == 1 ? "" : "s"), argspec.num_args + argspec.num_keywords + varargs_size);
     }
 
-    Py_DECREF(varargs);
+    Py_XDECREF(varargs);
 
     ////
     // Second, apply any keywords:

src/runtime/types.h

@@ -69,7 +69,7 @@ void setupAST();
 void setupSysEnd();
 
 BORROWED(BoxedDict*) getSysModulesDict();
-BoxedList* getSysPath();
+BORROWED(BoxedList*) getSysPath();
 extern "C" Box* getSysStdout();
 
 extern "C" BoxedTuple* EmptyTuple;