add ydb deps

1 files changed, 1612 insertions, 0 deletions

diff --git a/contrib/tools/python/src/Python/symtable.c b/contrib/tools/python/src/Python/symtable.c
new file mode 100644
index 0000000000..23aeaaa76f
--- /dev/null
+++ b/contrib/tools/python/src/Python/symtable.c
@@ -0,0 +1,1612 @@
+#include "Python.h"
+#include "Python-ast.h"
+#include "code.h"
+#include "symtable.h"
+#include "structmember.h"
+
+/* error strings used for warnings */
+#define GLOBAL_AFTER_ASSIGN \
+"name '%.400s' is assigned to before global declaration"
+
+#define GLOBAL_AFTER_USE \
+"name '%.400s' is used prior to global declaration"
+
+#define IMPORT_STAR_WARNING "import * only allowed at module level"
+
+#define RETURN_VAL_IN_GENERATOR \
+    "'return' with argument inside generator"
+
+
+static PySTEntryObject *
+ste_new(struct symtable *st, identifier name, _Py_block_ty block,
+              void *key, int lineno)
+{
+    PySTEntryObject *ste = NULL;
+    PyObject *k = NULL;
+
+    k = PyLong_FromVoidPtr(key);
+    if (k == NULL)
+        goto fail;
+    ste = PyObject_New(PySTEntryObject, &PySTEntry_Type);
+    if (ste == NULL) {
+        Py_DECREF(k);
+        goto fail;
+    }
+    ste->ste_table = st;
+    ste->ste_id = k; /* ste owns reference to k */
+
+    ste->ste_name = name;
+    Py_INCREF(name);
+
+    ste->ste_symbols = NULL;
+    ste->ste_varnames = NULL;
+    ste->ste_children = NULL;
+
+    ste->ste_symbols = PyDict_New();
+    if (ste->ste_symbols == NULL)
+        goto fail;
+
+    ste->ste_varnames = PyList_New(0);
+    if (ste->ste_varnames == NULL)
+        goto fail;
+
+    ste->ste_children = PyList_New(0);
+    if (ste->ste_children == NULL)
+        goto fail;
+
+    ste->ste_type = block;
+    ste->ste_unoptimized = 0;
+    ste->ste_nested = 0;
+    ste->ste_free = 0;
+    ste->ste_varargs = 0;
+    ste->ste_varkeywords = 0;
+    ste->ste_opt_lineno = 0;
+    ste->ste_tmpname = 0;
+    ste->ste_lineno = lineno;
+
+    if (st->st_cur != NULL &&
+        (st->st_cur->ste_nested ||
+         st->st_cur->ste_type == FunctionBlock))
+        ste->ste_nested = 1;
+    ste->ste_child_free = 0;
+    ste->ste_generator = 0;
+    ste->ste_returns_value = 0;
+
+    if (PyDict_SetItem(st->st_symbols, ste->ste_id, (PyObject *)ste) < 0)
+        goto fail;
+
+    return ste;
+ fail:
+    Py_XDECREF(ste);
+    return NULL;
+}
+
+static PyObject *
+ste_repr(PySTEntryObject *ste)
+{
+    char buf[256];
+
+    PyOS_snprintf(buf, sizeof(buf),
+                  "<symtable entry %.100s(%ld), line %d>",
+                  PyString_AS_STRING(ste->ste_name),
+                  PyInt_AS_LONG(ste->ste_id), ste->ste_lineno);
+    return PyString_FromString(buf);
+}
+
+static void
+ste_dealloc(PySTEntryObject *ste)
+{
+    ste->ste_table = NULL;
+    Py_XDECREF(ste->ste_id);
+    Py_XDECREF(ste->ste_name);
+    Py_XDECREF(ste->ste_symbols);
+    Py_XDECREF(ste->ste_varnames);
+    Py_XDECREF(ste->ste_children);
+    PyObject_Del(ste);
+}
+
+#define OFF(x) offsetof(PySTEntryObject, x)
+
+static PyMemberDef ste_memberlist[] = {
+    {"id",       T_OBJECT, OFF(ste_id), READONLY},
+    {"name",     T_OBJECT, OFF(ste_name), READONLY},
+    {"symbols",  T_OBJECT, OFF(ste_symbols), READONLY},
+    {"varnames", T_OBJECT, OFF(ste_varnames), READONLY},
+    {"children", T_OBJECT, OFF(ste_children), READONLY},
+    {"optimized",T_INT,    OFF(ste_unoptimized), READONLY},
+    {"nested",   T_INT,    OFF(ste_nested), READONLY},
+    {"type",     T_INT,    OFF(ste_type), READONLY},
+    {"lineno",   T_INT,    OFF(ste_lineno), READONLY},
+    {NULL}
+};
+
+PyTypeObject PySTEntry_Type = {
+    PyVarObject_HEAD_INIT(&PyType_Type, 0)
+    "symtable entry",
+    sizeof(PySTEntryObject),
+    0,
+    (destructor)ste_dealloc,                /* tp_dealloc */
+    0,                                      /* tp_print */
+    0,                                         /* tp_getattr */
+    0,                                          /* tp_setattr */
+    0,                                          /* tp_compare */
+    (reprfunc)ste_repr,                         /* tp_repr */
+    0,                                          /* tp_as_number */
+    0,                                          /* tp_as_sequence */
+    0,                                          /* tp_as_mapping */
+    0,                                          /* tp_hash */
+    0,                                          /* tp_call */
+    0,                                          /* tp_str */
+    PyObject_GenericGetAttr,                    /* tp_getattro */
+    0,                                          /* tp_setattro */
+    0,                                          /* tp_as_buffer */
+    Py_TPFLAGS_DEFAULT,                         /* tp_flags */
+    0,                                          /* tp_doc */
+    0,                                          /* tp_traverse */
+    0,                                          /* tp_clear */
+    0,                                          /* tp_richcompare */
+    0,                                          /* tp_weaklistoffset */
+    0,                                          /* tp_iter */
+    0,                                          /* tp_iternext */
+    0,                                          /* tp_methods */
+    ste_memberlist,                             /* tp_members */
+    0,                                          /* tp_getset */
+    0,                                          /* tp_base */
+    0,                                          /* tp_dict */
+    0,                                          /* tp_descr_get */
+    0,                                          /* tp_descr_set */
+    0,                                          /* tp_dictoffset */
+    0,                                          /* tp_init */
+    0,                                          /* tp_alloc */
+    0,                                          /* tp_new */
+};
+
+static int symtable_analyze(struct symtable *st);
+static int symtable_warn(struct symtable *st,
+                         PyObject *warn, const char *msg, int lineno);
+static int symtable_enter_block(struct symtable *st, identifier name,
+                                _Py_block_ty block, void *ast, int lineno);
+static int symtable_exit_block(struct symtable *st, void *ast);
+static int symtable_visit_stmt(struct symtable *st, stmt_ty s);
+static int symtable_visit_expr(struct symtable *st, expr_ty s);
+static int symtable_visit_listcomp(struct symtable *st, expr_ty e);
+static int symtable_visit_genexp(struct symtable *st, expr_ty s);
+static int symtable_visit_setcomp(struct symtable *st, expr_ty e);
+static int symtable_visit_dictcomp(struct symtable *st, expr_ty e);
+static int symtable_visit_arguments(struct symtable *st, arguments_ty);
+static int symtable_visit_excepthandler(struct symtable *st, excepthandler_ty);
+static int symtable_visit_alias(struct symtable *st, alias_ty);
+static int symtable_visit_comprehension(struct symtable *st, comprehension_ty);
+static int symtable_visit_keyword(struct symtable *st, keyword_ty);
+static int symtable_visit_slice(struct symtable *st, slice_ty);
+static int symtable_visit_params(struct symtable *st, asdl_seq *args, int top);
+static int symtable_visit_params_nested(struct symtable *st, asdl_seq *args);
+static int symtable_implicit_arg(struct symtable *st, int pos);
+
+
+static identifier top = NULL, lambda = NULL, genexpr = NULL, setcomp = NULL,
+    dictcomp = NULL;
+
+#define GET_IDENTIFIER(VAR) \
+    ((VAR) ? (VAR) : ((VAR) = PyString_InternFromString(# VAR)))
+
+#define DUPLICATE_ARGUMENT \
+"duplicate argument '%s' in function definition"
+
+static struct symtable *
+symtable_new(void)
+{
+    struct symtable *st;
+
+    st = (struct symtable *)PyMem_Malloc(sizeof(struct symtable));
+    if (st == NULL) {
+        PyErr_NoMemory();
+        return NULL;
+    }
+
+    st->st_filename = NULL;
+    st->st_symbols = NULL;
+
+    if ((st->st_stack = PyList_New(0)) == NULL)
+        goto fail;
+    if ((st->st_symbols = PyDict_New()) == NULL)
+        goto fail;
+    st->st_cur = NULL;
+    st->st_private = NULL;
+    return st;
+ fail:
+    PySymtable_Free(st);
+    return NULL;
+}
+
+struct symtable *
+PySymtable_Build(mod_ty mod, const char *filename, PyFutureFeatures *future)
+{
+    struct symtable *st = symtable_new();
+    asdl_seq *seq;
+    int i;
+
+    if (st == NULL)
+        return st;
+    st->st_filename = filename;
+    st->st_future = future;
+    if (!GET_IDENTIFIER(top) ||
+        !symtable_enter_block(st, top, ModuleBlock, (void *)mod, 0)) {
+        PySymtable_Free(st);
+        return NULL;
+    }
+
+    st->st_top = st->st_cur;
+    st->st_cur->ste_unoptimized = OPT_TOPLEVEL;
+    /* Any other top-level initialization? */
+    switch (mod->kind) {
+    case Module_kind:
+        seq = mod->v.Module.body;
+        for (i = 0; i < asdl_seq_LEN(seq); i++)
+            if (!symtable_visit_stmt(st,
+                        (stmt_ty)asdl_seq_GET(seq, i)))
+                goto error;
+        break;
+    case Expression_kind:
+        if (!symtable_visit_expr(st, mod->v.Expression.body))
+            goto error;
+        break;
+    case Interactive_kind:
+        seq = mod->v.Interactive.body;
+        for (i = 0; i < asdl_seq_LEN(seq); i++)
+            if (!symtable_visit_stmt(st,
+                        (stmt_ty)asdl_seq_GET(seq, i)))
+                goto error;
+        break;
+    case Suite_kind:
+        PyErr_SetString(PyExc_RuntimeError,
+                        "this compiler does not handle Suites");
+        goto error;
+    }
+    if (!symtable_exit_block(st, (void *)mod)) {
+        PySymtable_Free(st);
+        return NULL;
+    }
+    if (symtable_analyze(st))
+        return st;
+    PySymtable_Free(st);
+    return NULL;
+ error:
+    (void) symtable_exit_block(st, (void *)mod);
+    PySymtable_Free(st);
+    return NULL;
+}
+
+void
+PySymtable_Free(struct symtable *st)
+{
+    Py_XDECREF(st->st_symbols);
+    Py_XDECREF(st->st_stack);
+    PyMem_Free((void *)st);
+}
+
+PySTEntryObject *
+PySymtable_Lookup(struct symtable *st, void *key)
+{
+    PyObject *k, *v;
+
+    k = PyLong_FromVoidPtr(key);
+    if (k == NULL)
+        return NULL;
+    v = PyDict_GetItem(st->st_symbols, k);
+    if (v) {
+        assert(PySTEntry_Check(v));
+        Py_INCREF(v);
+    }
+    else {
+        PyErr_SetString(PyExc_KeyError,
+                        "unknown symbol table entry");
+    }
+
+    Py_DECREF(k);
+    return (PySTEntryObject *)v;
+}
+
+int
+PyST_GetScope(PySTEntryObject *ste, PyObject *name)
+{
+    PyObject *v = PyDict_GetItem(ste->ste_symbols, name);
+    if (!v)
+        return 0;
+    assert(PyInt_Check(v));
+    return (PyInt_AS_LONG(v) >> SCOPE_OFF) & SCOPE_MASK;
+}
+
+
+/* Analyze raw symbol information to determine scope of each name.
+
+   The next several functions are helpers for PySymtable_Analyze(),
+   which determines whether a name is local, global, or free.  In addition,
+   it determines which local variables are cell variables; they provide
+   bindings that are used for free variables in enclosed blocks.
+
+   There are also two kinds of free variables, implicit and explicit.  An
+   explicit global is declared with the global statement.  An implicit
+   global is a free variable for which the compiler has found no binding
+   in an enclosing function scope.  The implicit global is either a global
+   or a builtin.  Python's module and class blocks use the xxx_NAME opcodes
+   to handle these names to implement slightly odd semantics.  In such a
+   block, the name is treated as global until it is assigned to; then it
+   is treated as a local.
+
+   The symbol table requires two passes to determine the scope of each name.
+   The first pass collects raw facts from the AST: the name is a parameter
+   here, the name is used by not defined here, etc.  The second pass analyzes
+   these facts during a pass over the PySTEntryObjects created during pass 1.
+
+   When a function is entered during the second pass, the parent passes
+   the set of all name bindings visible to its children.  These bindings
+   are used to determine if the variable is free or an implicit global.
+   After doing the local analysis, it analyzes each of its child blocks
+   using an updated set of name bindings.
+
+   The children update the free variable set.  If a local variable is free
+   in a child, the variable is marked as a cell.  The current function must
+   provide runtime storage for the variable that may outlive the function's
+   frame.  Cell variables are removed from the free set before the analyze
+   function returns to its parent.
+
+   The sets of bound and free variables are implemented as dictionaries
+   mapping strings to None.
+*/
+
+#define SET_SCOPE(DICT, NAME, I) { \
+    PyObject *o = PyInt_FromLong(I); \
+    if (!o) \
+        return 0; \
+    if (PyDict_SetItem((DICT), (NAME), o) < 0) { \
+        Py_DECREF(o); \
+        return 0; \
+    } \
+    Py_DECREF(o); \
+}
+
+/* Decide on scope of name, given flags.
+
+   The namespace dictionaries may be modified to record information
+   about the new name.  For example, a new global will add an entry to
+   global.  A name that was global can be changed to local.
+*/
+
+static int
+analyze_name(PySTEntryObject *ste, PyObject *dict, PyObject *name, long flags,
+             PyObject *bound, PyObject *local, PyObject *free,
+             PyObject *global)
+{
+    if (flags & DEF_GLOBAL) {
+        if (flags & DEF_PARAM) {
+            PyErr_Format(PyExc_SyntaxError,
+                         "name '%s' is local and global",
+                         PyString_AS_STRING(name));
+            PyErr_SyntaxLocation(ste->ste_table->st_filename,
+                                 ste->ste_lineno);
+
+            return 0;
+        }
+        SET_SCOPE(dict, name, GLOBAL_EXPLICIT);
+        if (PyDict_SetItem(global, name, Py_None) < 0)
+            return 0;
+        if (bound && PyDict_GetItem(bound, name)) {
+            if (PyDict_DelItem(bound, name) < 0)
+                return 0;
+        }
+        return 1;
+    }
+    if (flags & DEF_BOUND) {
+        SET_SCOPE(dict, name, LOCAL);
+        if (PyDict_SetItem(local, name, Py_None) < 0)
+            return 0;
+        if (PyDict_GetItem(global, name)) {
+            if (PyDict_DelItem(global, name) < 0)
+                return 0;
+        }
+        return 1;
+    }
+    /* If an enclosing block has a binding for this name, it
+       is a free variable rather than a global variable.
+       Note that having a non-NULL bound implies that the block
+       is nested.
+    */
+    if (bound && PyDict_GetItem(bound, name)) {
+        SET_SCOPE(dict, name, FREE);
+        ste->ste_free = 1;
+        if (PyDict_SetItem(free, name, Py_None) < 0)
+            return 0;
+        return 1;
+    }
+    /* If a parent has a global statement, then call it global
+       explicit?  It could also be global implicit.
+     */
+    else if (global && PyDict_GetItem(global, name)) {
+        SET_SCOPE(dict, name, GLOBAL_IMPLICIT);
+        return 1;
+    }
+    else {
+        if (ste->ste_nested)
+            ste->ste_free = 1;
+        SET_SCOPE(dict, name, GLOBAL_IMPLICIT);
+        return 1;
+    }
+    /* Should never get here. */
+    PyErr_Format(PyExc_SystemError, "failed to set scope for %s",
+                 PyString_AS_STRING(name));
+    return 0;
+}
+
+#undef SET_SCOPE
+
+/* If a name is defined in free and also in locals, then this block
+   provides the binding for the free variable.  The name should be
+   marked CELL in this block and removed from the free list.
+
+   Note that the current block's free variables are included in free.
+   That's safe because no name can be free and local in the same scope.
+*/
+
+static int
+analyze_cells(PyObject *scope, PyObject *free)
+{
+    PyObject *name, *v, *w;
+    int success = 0;
+    Py_ssize_t pos = 0;
+
+    w = PyInt_FromLong(CELL);
+    if (!w)
+        return 0;
+    while (PyDict_Next(scope, &pos, &name, &v)) {
+        long flags;
+        assert(PyInt_Check(v));
+        flags = PyInt_AS_LONG(v);
+        if (flags != LOCAL)
+            continue;
+        if (!PyDict_GetItem(free, name))
+            continue;
+        /* Replace LOCAL with CELL for this name, and remove
+           from free. It is safe to replace the value of name
+           in the dict, because it will not cause a resize.
+         */
+        if (PyDict_SetItem(scope, name, w) < 0)
+            goto error;
+        if (PyDict_DelItem(free, name) < 0)
+            goto error;
+    }
+    success = 1;
+ error:
+    Py_DECREF(w);
+    return success;
+}
+
+/* Check for illegal statements in unoptimized namespaces */
+static int
+check_unoptimized(const PySTEntryObject* ste) {
+    char buf[300];
+    const char* trailer;
+
+    if (ste->ste_type != FunctionBlock || !ste->ste_unoptimized
+        || !(ste->ste_free || ste->ste_child_free))
+        return 1;
+
+    trailer = (ste->ste_child_free ?
+                   "contains a nested function with free variables" :
+                   "is a nested function");
+
+    switch (ste->ste_unoptimized) {
+    case OPT_TOPLEVEL: /* exec / import * at top-level is fine */
+    case OPT_EXEC: /* qualified exec is fine */
+        return 1;
+    case OPT_IMPORT_STAR:
+        PyOS_snprintf(buf, sizeof(buf),
+                      "import * is not allowed in function '%.100s' "
+                      "because it %s",
+                      PyString_AS_STRING(ste->ste_name), trailer);
+        break;
+    case OPT_BARE_EXEC:
+        PyOS_snprintf(buf, sizeof(buf),
+                      "unqualified exec is not allowed in function "
+                      "'%.100s' because it %s",
+                      PyString_AS_STRING(ste->ste_name), trailer);
+        break;
+    default:
+        PyOS_snprintf(buf, sizeof(buf),
+                      "function '%.100s' uses import * and bare exec, "
+                      "which are illegal because it %s",
+                      PyString_AS_STRING(ste->ste_name), trailer);
+        break;
+    }
+
+    PyErr_SetString(PyExc_SyntaxError, buf);
+    PyErr_SyntaxLocation(ste->ste_table->st_filename,
+                         ste->ste_opt_lineno);
+    return 0;
+}
+
+/* Enter the final scope information into the st_symbols dict.
+ *
+ * All arguments are dicts.  Modifies symbols, others are read-only.
+*/
+static int
+update_symbols(PyObject *symbols, PyObject *scope,
+               PyObject *bound, PyObject *free, int classflag)
+{
+    PyObject *name, *v, *u, *w, *free_value = NULL;
+    Py_ssize_t pos = 0;
+
+    while (PyDict_Next(symbols, &pos, &name, &v)) {
+        long i, flags;
+        assert(PyInt_Check(v));
+        flags = PyInt_AS_LONG(v);
+        w = PyDict_GetItem(scope, name);
+        assert(w && PyInt_Check(w));
+        i = PyInt_AS_LONG(w);
+        flags |= (i << SCOPE_OFF);
+        u = PyInt_FromLong(flags);
+        if (!u)
+            return 0;
+        if (PyDict_SetItem(symbols, name, u) < 0) {
+            Py_DECREF(u);
+            return 0;
+        }
+        Py_DECREF(u);
+    }
+
+    free_value = PyInt_FromLong(FREE << SCOPE_OFF);
+    if (!free_value)
+        return 0;
+
+    /* add a free variable when it's only use is for creating a closure */
+    pos = 0;
+    while (PyDict_Next(free, &pos, &name, &v)) {
+        PyObject *o = PyDict_GetItem(symbols, name);
+
+        if (o) {
+            /* It could be a free variable in a method of
+               the class that has the same name as a local
+               or global in the class scope.
+            */
+            if  (classflag &&
+                 PyInt_AS_LONG(o) & (DEF_BOUND | DEF_GLOBAL)) {
+                long i = PyInt_AS_LONG(o) | DEF_FREE_CLASS;
+                o = PyInt_FromLong(i);
+                if (!o) {
+                    Py_DECREF(free_value);
+                    return 0;
+                }
+                if (PyDict_SetItem(symbols, name, o) < 0) {
+                    Py_DECREF(o);
+                    Py_DECREF(free_value);
+                    return 0;
+                }
+                Py_DECREF(o);
+            }
+            /* else it's not free, probably a cell */
+            continue;
+        }
+        if (!PyDict_GetItem(bound, name))
+            continue;       /* it's a global */
+
+        if (PyDict_SetItem(symbols, name, free_value) < 0) {
+            Py_DECREF(free_value);
+            return 0;
+        }
+    }
+    Py_DECREF(free_value);
+    return 1;
+}
+
+/* Make final symbol table decisions for block of ste.
+
+   Arguments:
+   ste -- current symtable entry (input/output)
+   bound -- set of variables bound in enclosing scopes (input).  bound
+       is NULL for module blocks.
+   free -- set of free variables in enclosed scopes (output)
+   globals -- set of declared global variables in enclosing scopes (input)
+
+   The implementation uses two mutually recursive functions,
+   analyze_block() and analyze_child_block().  analyze_block() is
+   responsible for analyzing the individual names defined in a block.
+   analyze_child_block() prepares temporary namespace dictionaries
+   used to evaluated nested blocks.
+
+   The two functions exist because a child block should see the name
+   bindings of its enclosing blocks, but those bindings should not
+   propagate back to a parent block.
+*/
+
+static int
+analyze_child_block(PySTEntryObject *entry, PyObject *bound, PyObject *free,
+                    PyObject *global, PyObject* child_free);
+
+static int
+analyze_block(PySTEntryObject *ste, PyObject *bound, PyObject *free,
+              PyObject *global)
+{
+    PyObject *name, *v, *local = NULL, *scope = NULL;
+    PyObject *newbound = NULL, *newglobal = NULL;
+    PyObject *newfree = NULL, *allfree = NULL;
+    int i, success = 0;
+    Py_ssize_t pos = 0;
+
+    local = PyDict_New();  /* collect new names bound in block */
+    if (!local)
+        goto error;
+    scope = PyDict_New(); /* collect scopes defined for each name */
+    if (!scope)
+        goto error;
+
+    /* Allocate new global and bound variable dictionaries.  These
+       dictionaries hold the names visible in nested blocks.  For
+       ClassBlocks, the bound and global names are initialized
+       before analyzing names, because class bindings aren't
+       visible in methods.  For other blocks, they are initialized
+       after names are analyzed.
+     */
+
+    /* TODO(jhylton): Package these dicts in a struct so that we
+       can write reasonable helper functions?
+    */
+    newglobal = PyDict_New();
+    if (!newglobal)
+        goto error;
+    newbound = PyDict_New();
+    if (!newbound)
+        goto error;
+    newfree = PyDict_New();
+    if (!newfree)
+        goto error;
+
+    if (ste->ste_type == ClassBlock) {
+        if (PyDict_Update(newglobal, global) < 0)
+            goto error;
+        if (bound)
+            if (PyDict_Update(newbound, bound) < 0)
+                goto error;
+    }
+
+    while (PyDict_Next(ste->ste_symbols, &pos, &name, &v)) {
+        long flags = PyInt_AS_LONG(v);
+        if (!analyze_name(ste, scope, name, flags,
+                          bound, local, free, global))
+            goto error;
+    }
+
+    if (ste->ste_type != ClassBlock) {
+        if (ste->ste_type == FunctionBlock) {
+            if (PyDict_Update(newbound, local) < 0)
+                goto error;
+        }
+        if (bound) {
+            if (PyDict_Update(newbound, bound) < 0)
+                goto error;
+        }
+        if (PyDict_Update(newglobal, global) < 0)
+            goto error;
+    }
+
+    /* Recursively call analyze_block() on each child block.
+
+       newbound, newglobal now contain the names visible in
+       nested blocks.  The free variables in the children will
+       be collected in allfree.
+    */
+    allfree = PyDict_New();
+    if (!allfree)
+        goto error;
+    for (i = 0; i < PyList_GET_SIZE(ste->ste_children); ++i) {
+        PyObject *c = PyList_GET_ITEM(ste->ste_children, i);
+        PySTEntryObject* entry;
+        assert(c && PySTEntry_Check(c));
+        entry = (PySTEntryObject*)c;
+        if (!analyze_child_block(entry, newbound, newfree, newglobal,
+                                 allfree))
+            goto error;
+        if (entry->ste_free || entry->ste_child_free)
+            ste->ste_child_free = 1;
+    }
+
+    if (PyDict_Update(newfree, allfree) < 0)
+        goto error;
+    if (ste->ste_type == FunctionBlock && !analyze_cells(scope, newfree))
+        goto error;
+    if (!update_symbols(ste->ste_symbols, scope, bound, newfree,
+                        ste->ste_type == ClassBlock))
+        goto error;
+    if (!check_unoptimized(ste))
+        goto error;
+
+    if (PyDict_Update(free, newfree) < 0)
+        goto error;
+    success = 1;
+ error:
+    Py_XDECREF(local);
+    Py_XDECREF(scope);
+    Py_XDECREF(newbound);
+    Py_XDECREF(newglobal);
+    Py_XDECREF(newfree);
+    Py_XDECREF(allfree);
+    if (!success)
+        assert(PyErr_Occurred());
+    return success;
+}
+
+static int
+analyze_child_block(PySTEntryObject *entry, PyObject *bound, PyObject *free,
+                    PyObject *global, PyObject* child_free)
+{
+    PyObject *temp_bound = NULL, *temp_global = NULL, *temp_free = NULL;
+
+    /* Copy the bound and global dictionaries.
+
+       These dictionaries are used by all blocks enclosed by the
+       current block.  The analyze_block() call modifies these
+       dictionaries.
+
+    */
+    temp_bound = PyDict_New();
+    if (!temp_bound)
+        goto error;
+    if (PyDict_Update(temp_bound, bound) < 0)
+        goto error;
+    temp_free = PyDict_New();
+    if (!temp_free)
+        goto error;
+    if (PyDict_Update(temp_free, free) < 0)
+        goto error;
+    temp_global = PyDict_New();
+    if (!temp_global)
+        goto error;
+    if (PyDict_Update(temp_global, global) < 0)
+        goto error;
+
+    if (!analyze_block(entry, temp_bound, temp_free, temp_global))
+        goto error;
+    if (PyDict_Update(child_free, temp_free) < 0)
+        goto error;
+    Py_DECREF(temp_bound);
+    Py_DECREF(temp_free);
+    Py_DECREF(temp_global);
+    return 1;
+ error:
+    Py_XDECREF(temp_bound);
+    Py_XDECREF(temp_free);
+    Py_XDECREF(temp_global);
+    return 0;
+}
+
+static int
+symtable_analyze(struct symtable *st)
+{
+    PyObject *free, *global;
+    int r;
+
+    free = PyDict_New();
+    if (!free)
+        return 0;
+    global = PyDict_New();
+    if (!global) {
+        Py_DECREF(free);
+        return 0;
+    }
+    r = analyze_block(st->st_top, NULL, free, global);
+    Py_DECREF(free);
+    Py_DECREF(global);
+    return r;
+}
+
+
+static int
+symtable_warn(struct symtable *st, PyObject *warn, const char *msg, int lineno)
+{
+    if (lineno < 0) {
+        lineno = st->st_cur->ste_lineno;
+    }
+    if (PyErr_WarnExplicit(warn, msg, st->st_filename, lineno, NULL, NULL) < 0) {
+        if (PyErr_ExceptionMatches(warn)) {
+            /* Replace the warning exception with a SyntaxError
+               to get a more accurate error report */
+            PyErr_Clear();
+            PyErr_SetString(PyExc_SyntaxError, msg);
+            PyErr_SyntaxLocation(st->st_filename, lineno);
+        }
+        return 0;
+    }
+    return 1;
+}
+
+/* symtable_enter_block() gets a reference via ste_new.
+   This reference is released when the block is exited, via the DECREF
+   in symtable_exit_block().
+*/
+
+static int
+symtable_exit_block(struct symtable *st, void *ast)
+{
+    Py_ssize_t end;
+
+    Py_CLEAR(st->st_cur);
+    end = PyList_GET_SIZE(st->st_stack) - 1;
+    if (end >= 0) {
+        st->st_cur = (PySTEntryObject *)PyList_GET_ITEM(st->st_stack,
+                                                        end);
+        if (st->st_cur == NULL)
+            return 0;
+        Py_INCREF(st->st_cur);
+        if (PySequence_DelItem(st->st_stack, end) < 0)
+            return 0;
+    }
+    return 1;
+}
+
+static int
+symtable_enter_block(struct symtable *st, identifier name, _Py_block_ty block,
+                     void *ast, int lineno)
+{
+    PySTEntryObject *prev = NULL;
+
+    if (st->st_cur) {
+        prev = st->st_cur;
+        if (PyList_Append(st->st_stack, (PyObject *)st->st_cur) < 0) {
+            return 0;
+        }
+        Py_DECREF(st->st_cur);
+    }
+    st->st_cur = ste_new(st, name, block, ast, lineno);
+    if (st->st_cur == NULL)
+        return 0;
+    if (block == ModuleBlock)
+        st->st_global = st->st_cur->ste_symbols;
+    if (prev) {
+        if (PyList_Append(prev->ste_children,
+                          (PyObject *)st->st_cur) < 0) {
+            return 0;
+        }
+    }
+    return 1;
+}
+
+static long
+symtable_lookup(struct symtable *st, PyObject *name)
+{
+    PyObject *o;
+    PyObject *mangled = _Py_Mangle(st->st_private, name);
+    if (!mangled)
+        return 0;
+    o = PyDict_GetItem(st->st_cur->ste_symbols, mangled);
+    Py_DECREF(mangled);
+    if (!o)
+        return 0;
+    return PyInt_AsLong(o);
+}
+
+static int
+symtable_add_def(struct symtable *st, PyObject *name, int flag)
+{
+    PyObject *o;
+    PyObject *dict;
+    long val;
+    PyObject *mangled = _Py_Mangle(st->st_private, name);
+
+    if (!mangled)
+        return 0;
+    dict = st->st_cur->ste_symbols;
+    if ((o = PyDict_GetItem(dict, mangled))) {
+        val = PyInt_AS_LONG(o);
+        if ((flag & DEF_PARAM) && (val & DEF_PARAM)) {
+            /* Is it better to use 'mangled' or 'name' here? */
+            PyErr_Format(PyExc_SyntaxError, DUPLICATE_ARGUMENT,
+                         PyString_AsString(name));
+            PyErr_SyntaxLocation(st->st_filename,
+                               st->st_cur->ste_lineno);
+            goto error;
+        }
+        val |= flag;
+    } else
+        val = flag;
+    o = PyInt_FromLong(val);
+    if (o == NULL)
+        goto error;
+    if (PyDict_SetItem(dict, mangled, o) < 0) {
+        Py_DECREF(o);
+        goto error;
+    }
+    Py_DECREF(o);
+
+    if (flag & DEF_PARAM) {
+        if (PyList_Append(st->st_cur->ste_varnames, mangled) < 0)
+            goto error;
+    } else      if (flag & DEF_GLOBAL) {
+        /* XXX need to update DEF_GLOBAL for other flags too;
+           perhaps only DEF_FREE_GLOBAL */
+        val = flag;
+        if ((o = PyDict_GetItem(st->st_global, mangled))) {
+            val |= PyInt_AS_LONG(o);
+        }
+        o = PyInt_FromLong(val);
+        if (o == NULL)
+            goto error;
+        if (PyDict_SetItem(st->st_global, mangled, o) < 0) {
+            Py_DECREF(o);
+            goto error;
+        }
+        Py_DECREF(o);
+    }
+    Py_DECREF(mangled);
+    return 1;
+
+error:
+    Py_DECREF(mangled);
+    return 0;
+}
+
+/* VISIT, VISIT_SEQ and VIST_SEQ_TAIL take an ASDL type as their second argument.
+   They use the ASDL name to synthesize the name of the C type and the visit
+   function.
+
+   VISIT_SEQ_TAIL permits the start of an ASDL sequence to be skipped, which is
+   useful if the first node in the sequence requires special treatment.
+*/
+
+#define VISIT(ST, TYPE, V) \
+    if (!symtable_visit_ ## TYPE((ST), (V))) \
+        return 0;
+
+#define VISIT_IN_BLOCK(ST, TYPE, V, S) \
+    if (!symtable_visit_ ## TYPE((ST), (V))) { \
+        symtable_exit_block((ST), (S)); \
+        return 0; \
+    }
+
+#define VISIT_SEQ(ST, TYPE, SEQ) { \
+    int i; \
+    asdl_seq *seq = (SEQ); /* avoid variable capture */ \
+    for (i = 0; i < asdl_seq_LEN(seq); i++) { \
+        TYPE ## _ty elt = (TYPE ## _ty)asdl_seq_GET(seq, i); \
+        if (!symtable_visit_ ## TYPE((ST), elt)) \
+            return 0; \
+    } \
+}
+
+#define VISIT_SEQ_IN_BLOCK(ST, TYPE, SEQ, S) { \
+    int i; \
+    asdl_seq *seq = (SEQ); /* avoid variable capture */ \
+    for (i = 0; i < asdl_seq_LEN(seq); i++) { \
+        TYPE ## _ty elt = (TYPE ## _ty)asdl_seq_GET(seq, i); \
+        if (!symtable_visit_ ## TYPE((ST), elt)) { \
+            symtable_exit_block((ST), (S)); \
+            return 0; \
+        } \
+    } \
+}
+
+#define VISIT_SEQ_TAIL(ST, TYPE, SEQ, START) { \
+    int i; \
+    asdl_seq *seq = (SEQ); /* avoid variable capture */ \
+    for (i = (START); i < asdl_seq_LEN(seq); i++) { \
+        TYPE ## _ty elt = (TYPE ## _ty)asdl_seq_GET(seq, i); \
+        if (!symtable_visit_ ## TYPE((ST), elt)) \
+            return 0; \
+    } \
+}
+
+#define VISIT_SEQ_TAIL_IN_BLOCK(ST, TYPE, SEQ, START, S) { \
+    int i; \
+    asdl_seq *seq = (SEQ); /* avoid variable capture */ \
+    for (i = (START); i < asdl_seq_LEN(seq); i++) { \
+        TYPE ## _ty elt = (TYPE ## _ty)asdl_seq_GET(seq, i); \
+        if (!symtable_visit_ ## TYPE((ST), elt)) { \
+            symtable_exit_block((ST), (S)); \
+            return 0; \
+        } \
+    } \
+}
+
+static int
+symtable_visit_stmt(struct symtable *st, stmt_ty s)
+{
+    switch (s->kind) {
+    case FunctionDef_kind:
+        if (!symtable_add_def(st, s->v.FunctionDef.name, DEF_LOCAL))
+            return 0;
+        if (s->v.FunctionDef.args->defaults)
+            VISIT_SEQ(st, expr, s->v.FunctionDef.args->defaults);
+        if (s->v.FunctionDef.decorator_list)
+            VISIT_SEQ(st, expr, s->v.FunctionDef.decorator_list);
+        if (!symtable_enter_block(st, s->v.FunctionDef.name,
+                                  FunctionBlock, (void *)s, s->lineno))
+            return 0;
+        VISIT_IN_BLOCK(st, arguments, s->v.FunctionDef.args, s);
+        VISIT_SEQ_IN_BLOCK(st, stmt, s->v.FunctionDef.body, s);
+        if (!symtable_exit_block(st, s))
+            return 0;
+        break;
+    case ClassDef_kind: {
+        PyObject *tmp;
+        if (!symtable_add_def(st, s->v.ClassDef.name, DEF_LOCAL))
+            return 0;
+        VISIT_SEQ(st, expr, s->v.ClassDef.bases);
+        if (s->v.ClassDef.decorator_list)
+            VISIT_SEQ(st, expr, s->v.ClassDef.decorator_list);
+        if (!symtable_enter_block(st, s->v.ClassDef.name, ClassBlock,
+                                  (void *)s, s->lineno))
+            return 0;
+        tmp = st->st_private;
+        st->st_private = s->v.ClassDef.name;
+        VISIT_SEQ_IN_BLOCK(st, stmt, s->v.ClassDef.body, s);
+        st->st_private = tmp;
+        if (!symtable_exit_block(st, s))
+            return 0;
+        break;
+    }
+    case Return_kind:
+        if (s->v.Return.value) {
+            VISIT(st, expr, s->v.Return.value);
+            st->st_cur->ste_returns_value = 1;
+            if (st->st_cur->ste_generator) {
+                PyErr_SetString(PyExc_SyntaxError,
+                    RETURN_VAL_IN_GENERATOR);
+                PyErr_SyntaxLocation(st->st_filename,
+                             s->lineno);
+                return 0;
+            }
+        }
+        break;
+    case Delete_kind:
+        VISIT_SEQ(st, expr, s->v.Delete.targets);
+        break;
+    case Assign_kind:
+        VISIT_SEQ(st, expr, s->v.Assign.targets);
+        VISIT(st, expr, s->v.Assign.value);
+        break;
+    case AugAssign_kind:
+        VISIT(st, expr, s->v.AugAssign.target);
+        VISIT(st, expr, s->v.AugAssign.value);
+        break;
+    case Print_kind:
+        if (s->v.Print.dest)
+            VISIT(st, expr, s->v.Print.dest);
+        VISIT_SEQ(st, expr, s->v.Print.values);
+        break;
+    case For_kind:
+        VISIT(st, expr, s->v.For.target);
+        VISIT(st, expr, s->v.For.iter);
+        VISIT_SEQ(st, stmt, s->v.For.body);
+        if (s->v.For.orelse)
+            VISIT_SEQ(st, stmt, s->v.For.orelse);
+        break;
+    case While_kind:
+        VISIT(st, expr, s->v.While.test);
+        VISIT_SEQ(st, stmt, s->v.While.body);
+        if (s->v.While.orelse)
+            VISIT_SEQ(st, stmt, s->v.While.orelse);
+        break;
+    case If_kind:
+        /* XXX if 0: and lookup_yield() hacks */
+        VISIT(st, expr, s->v.If.test);
+        VISIT_SEQ(st, stmt, s->v.If.body);
+        if (s->v.If.orelse)
+            VISIT_SEQ(st, stmt, s->v.If.orelse);
+        break;
+    case Raise_kind:
+        if (s->v.Raise.type) {
+            VISIT(st, expr, s->v.Raise.type);
+            if (s->v.Raise.inst) {
+                VISIT(st, expr, s->v.Raise.inst);
+                if (s->v.Raise.tback)
+                    VISIT(st, expr, s->v.Raise.tback);
+            }
+        }
+        break;
+    case TryExcept_kind:
+        VISIT_SEQ(st, stmt, s->v.TryExcept.body);
+        VISIT_SEQ(st, stmt, s->v.TryExcept.orelse);
+        VISIT_SEQ(st, excepthandler, s->v.TryExcept.handlers);
+        break;
+    case TryFinally_kind:
+        VISIT_SEQ(st, stmt, s->v.TryFinally.body);
+        VISIT_SEQ(st, stmt, s->v.TryFinally.finalbody);
+        break;
+    case Assert_kind:
+        VISIT(st, expr, s->v.Assert.test);
+        if (s->v.Assert.msg)
+            VISIT(st, expr, s->v.Assert.msg);
+        break;
+    case Import_kind:
+        VISIT_SEQ(st, alias, s->v.Import.names);
+        /* XXX Don't have the lineno available inside
+           visit_alias */
+        if (st->st_cur->ste_unoptimized && !st->st_cur->ste_opt_lineno)
+            st->st_cur->ste_opt_lineno = s->lineno;
+        break;
+    case ImportFrom_kind:
+        VISIT_SEQ(st, alias, s->v.ImportFrom.names);
+        /* XXX Don't have the lineno available inside
+           visit_alias */
+        if (st->st_cur->ste_unoptimized && !st->st_cur->ste_opt_lineno)
+            st->st_cur->ste_opt_lineno = s->lineno;
+        break;
+    case Exec_kind:
+        VISIT(st, expr, s->v.Exec.body);
+        if (!st->st_cur->ste_opt_lineno)
+            st->st_cur->ste_opt_lineno = s->lineno;
+        if (s->v.Exec.globals) {
+            st->st_cur->ste_unoptimized |= OPT_EXEC;
+            VISIT(st, expr, s->v.Exec.globals);
+            if (s->v.Exec.locals)
+                VISIT(st, expr, s->v.Exec.locals);
+        } else {
+            st->st_cur->ste_unoptimized |= OPT_BARE_EXEC;
+        }
+        break;
+    case Global_kind: {
+        int i;
+        asdl_seq *seq = s->v.Global.names;
+        for (i = 0; i < asdl_seq_LEN(seq); i++) {
+            identifier name = (identifier)asdl_seq_GET(seq, i);
+            char *c_name = PyString_AS_STRING(name);
+            long cur = symtable_lookup(st, name);
+            if (cur < 0)
+                return 0;
+            if (cur & (DEF_LOCAL | USE)) {
+                char buf[256];
+                if (cur & DEF_LOCAL)
+                    PyOS_snprintf(buf, sizeof(buf),
+                                  GLOBAL_AFTER_ASSIGN,
+                                  c_name);
+                else
+                    PyOS_snprintf(buf, sizeof(buf),
+                                  GLOBAL_AFTER_USE,
+                                  c_name);
+                if (!symtable_warn(st, PyExc_SyntaxWarning, buf, s->lineno))
+                    return 0;
+            }
+            if (!symtable_add_def(st, name, DEF_GLOBAL))
+                return 0;
+        }
+        break;
+    }
+    case Expr_kind:
+        VISIT(st, expr, s->v.Expr.value);
+        break;
+    case Pass_kind:
+    case Break_kind:
+    case Continue_kind:
+        /* nothing to do here */
+        break;
+    case With_kind:
+        VISIT(st, expr, s->v.With.context_expr);
+        if (s->v.With.optional_vars) {
+            VISIT(st, expr, s->v.With.optional_vars);
+        }
+        VISIT_SEQ(st, stmt, s->v.With.body);
+        break;
+    }
+    return 1;
+}
+
+static int
+symtable_visit_expr(struct symtable *st, expr_ty e)
+{
+    switch (e->kind) {
+    case BoolOp_kind:
+        VISIT_SEQ(st, expr, e->v.BoolOp.values);
+        break;
+    case BinOp_kind:
+        VISIT(st, expr, e->v.BinOp.left);
+        VISIT(st, expr, e->v.BinOp.right);
+        break;
+    case UnaryOp_kind:
+        VISIT(st, expr, e->v.UnaryOp.operand);
+        break;
+    case Lambda_kind: {
+        if (!GET_IDENTIFIER(lambda))
+            return 0;
+        if (e->v.Lambda.args->defaults)
+            VISIT_SEQ(st, expr, e->v.Lambda.args->defaults);
+        if (!symtable_enter_block(st, lambda,
+                                  FunctionBlock, (void *)e, e->lineno))
+            return 0;
+        VISIT_IN_BLOCK(st, arguments, e->v.Lambda.args, (void*)e);
+        VISIT_IN_BLOCK(st, expr, e->v.Lambda.body, (void*)e);
+        if (!symtable_exit_block(st, (void *)e))
+            return 0;
+        break;
+    }
+    case IfExp_kind:
+        VISIT(st, expr, e->v.IfExp.test);
+        VISIT(st, expr, e->v.IfExp.body);
+        VISIT(st, expr, e->v.IfExp.orelse);
+        break;
+    case Dict_kind:
+        VISIT_SEQ(st, expr, e->v.Dict.keys);
+        VISIT_SEQ(st, expr, e->v.Dict.values);
+        break;
+    case Set_kind:
+        VISIT_SEQ(st, expr, e->v.Set.elts);
+        break;
+    case ListComp_kind:
+        if (!symtable_visit_listcomp(st, e))
+            return 0;
+        break;
+    case GeneratorExp_kind:
+        if (!symtable_visit_genexp(st, e))
+            return 0;
+        break;
+    case SetComp_kind:
+        if (!symtable_visit_setcomp(st, e))
+            return 0;
+        break;
+    case DictComp_kind:
+        if (!symtable_visit_dictcomp(st, e))
+            return 0;
+        break;
+    case Yield_kind:
+        if (e->v.Yield.value)
+            VISIT(st, expr, e->v.Yield.value);
+        st->st_cur->ste_generator = 1;
+        if (st->st_cur->ste_returns_value) {
+            PyErr_SetString(PyExc_SyntaxError,
+                RETURN_VAL_IN_GENERATOR);
+            PyErr_SyntaxLocation(st->st_filename,
+                         e->lineno);
+            return 0;
+        }
+        break;
+    case Compare_kind:
+        VISIT(st, expr, e->v.Compare.left);
+        VISIT_SEQ(st, expr, e->v.Compare.comparators);
+        break;
+    case Call_kind:
+        VISIT(st, expr, e->v.Call.func);
+        VISIT_SEQ(st, expr, e->v.Call.args);
+        VISIT_SEQ(st, keyword, e->v.Call.keywords);
+        if (e->v.Call.starargs)
+            VISIT(st, expr, e->v.Call.starargs);
+        if (e->v.Call.kwargs)
+            VISIT(st, expr, e->v.Call.kwargs);
+        break;
+    case Repr_kind:
+        VISIT(st, expr, e->v.Repr.value);
+        break;
+    case Num_kind:
+    case Str_kind:
+        /* Nothing to do here. */
+        break;
+    /* The following exprs can be assignment targets. */
+    case Attribute_kind:
+        VISIT(st, expr, e->v.Attribute.value);
+        break;
+    case Subscript_kind:
+        VISIT(st, expr, e->v.Subscript.value);
+        VISIT(st, slice, e->v.Subscript.slice);
+        break;
+    case Name_kind:
+        if (!symtable_add_def(st, e->v.Name.id,
+                              e->v.Name.ctx == Load ? USE : DEF_LOCAL))
+            return 0;
+        break;
+    /* child nodes of List and Tuple will have expr_context set */
+    case List_kind:
+        VISIT_SEQ(st, expr, e->v.List.elts);
+        break;
+    case Tuple_kind:
+        VISIT_SEQ(st, expr, e->v.Tuple.elts);
+        break;
+    }
+    return 1;
+}
+
+static int
+symtable_implicit_arg(struct symtable *st, int pos)
+{
+    PyObject *id = PyString_FromFormat(".%d", pos);
+    if (id == NULL)
+        return 0;
+    if (!symtable_add_def(st, id, DEF_PARAM)) {
+        Py_DECREF(id);
+        return 0;
+    }
+    Py_DECREF(id);
+    return 1;
+}
+
+static int
+symtable_visit_params(struct symtable *st, asdl_seq *args, int toplevel)
+{
+    int i;
+
+    /* go through all the toplevel arguments first */
+    for (i = 0; i < asdl_seq_LEN(args); i++) {
+        expr_ty arg = (expr_ty)asdl_seq_GET(args, i);
+        if (arg->kind == Name_kind) {
+            assert(arg->v.Name.ctx == Param ||
+                   (arg->v.Name.ctx == Store && !toplevel));
+            if (!symtable_add_def(st, arg->v.Name.id, DEF_PARAM))
+                return 0;
+        }
+        else if (arg->kind == Tuple_kind) {
+            assert(arg->v.Tuple.ctx == Store);
+            if (toplevel) {
+                if (!symtable_implicit_arg(st, i))
+                    return 0;
+            }
+        }
+        else {
+            PyErr_SetString(PyExc_SyntaxError,
+                            "invalid expression in parameter list");
+            PyErr_SyntaxLocation(st->st_filename,
+                                 st->st_cur->ste_lineno);
+            return 0;
+        }
+    }
+
+    if (!toplevel) {
+        if (!symtable_visit_params_nested(st, args))
+            return 0;
+    }
+
+    return 1;
+}
+
+static int
+symtable_visit_params_nested(struct symtable *st, asdl_seq *args)
+{
+    int i;
+    for (i = 0; i < asdl_seq_LEN(args); i++) {
+        expr_ty arg = (expr_ty)asdl_seq_GET(args, i);
+        if (arg->kind == Tuple_kind &&
+            !symtable_visit_params(st, arg->v.Tuple.elts, 0))
+            return 0;
+    }
+
+    return 1;
+}
+
+static int
+symtable_visit_arguments(struct symtable *st, arguments_ty a)
+{
+    /* skip default arguments inside function block
+       XXX should ast be different?
+    */
+    if (a->args && !symtable_visit_params(st, a->args, 1))
+        return 0;
+    if (a->vararg) {
+        if (!symtable_add_def(st, a->vararg, DEF_PARAM))
+            return 0;
+        st->st_cur->ste_varargs = 1;
+    }
+    if (a->kwarg) {
+        if (!symtable_add_def(st, a->kwarg, DEF_PARAM))
+            return 0;
+        st->st_cur->ste_varkeywords = 1;
+    }
+    if (a->args && !symtable_visit_params_nested(st, a->args))
+        return 0;
+    return 1;
+}
+
+
+static int
+symtable_visit_excepthandler(struct symtable *st, excepthandler_ty eh)
+{
+    if (eh->v.ExceptHandler.type)
+        VISIT(st, expr, eh->v.ExceptHandler.type);
+    if (eh->v.ExceptHandler.name)
+        VISIT(st, expr, eh->v.ExceptHandler.name);
+    VISIT_SEQ(st, stmt, eh->v.ExceptHandler.body);
+    return 1;
+}
+
+
+static int
+symtable_visit_alias(struct symtable *st, alias_ty a)
+{
+    /* Compute store_name, the name actually bound by the import
+       operation.  It is different than a->name when a->name is a
+       dotted package name (e.g. spam.eggs)
+    */
+    PyObject *store_name;
+    PyObject *name = (a->asname == NULL) ? a->name : a->asname;
+    const char *base = PyString_AS_STRING(name);
+    char *dot = strchr(base, '.');
+    if (dot) {
+        store_name = PyString_FromStringAndSize(base, dot - base);
+        if (!store_name)
+            return 0;
+    }
+    else {
+        store_name = name;
+        Py_INCREF(store_name);
+    }
+    if (strcmp(PyString_AS_STRING(name), "*")) {
+        int r = symtable_add_def(st, store_name, DEF_IMPORT);
+        Py_DECREF(store_name);
+        return r;
+    }
+    else {
+        if (st->st_cur->ste_type != ModuleBlock &&
+            !symtable_warn(st, PyExc_SyntaxWarning, IMPORT_STAR_WARNING, -1))
+        {
+            Py_DECREF(store_name);
+            return 0;
+        }
+        st->st_cur->ste_unoptimized |= OPT_IMPORT_STAR;
+        Py_DECREF(store_name);
+        return 1;
+    }
+}
+
+
+static int
+symtable_visit_comprehension(struct symtable *st, comprehension_ty lc)
+{
+    VISIT(st, expr, lc->target);
+    VISIT(st, expr, lc->iter);
+    VISIT_SEQ(st, expr, lc->ifs);
+    return 1;
+}
+
+
+static int
+symtable_visit_keyword(struct symtable *st, keyword_ty k)
+{
+    VISIT(st, expr, k->value);
+    return 1;
+}
+
+
+static int
+symtable_visit_slice(struct symtable *st, slice_ty s)
+{
+    switch (s->kind) {
+    case Slice_kind:
+        if (s->v.Slice.lower)
+            VISIT(st, expr, s->v.Slice.lower)
+        if (s->v.Slice.upper)
+            VISIT(st, expr, s->v.Slice.upper)
+        if (s->v.Slice.step)
+            VISIT(st, expr, s->v.Slice.step)
+        break;
+    case ExtSlice_kind:
+        VISIT_SEQ(st, slice, s->v.ExtSlice.dims)
+        break;
+    case Index_kind:
+        VISIT(st, expr, s->v.Index.value)
+        break;
+    case Ellipsis_kind:
+        break;
+    }
+    return 1;
+}
+
+static int
+symtable_new_tmpname(struct symtable *st)
+{
+    char tmpname[256];
+    identifier tmp;
+
+    PyOS_snprintf(tmpname, sizeof(tmpname), "_[%d]",
+                  ++st->st_cur->ste_tmpname);
+    tmp = PyString_InternFromString(tmpname);
+    if (!tmp)
+        return 0;
+    if (!symtable_add_def(st, tmp, DEF_LOCAL))
+        return 0;
+    Py_DECREF(tmp);
+    return 1;
+}
+
+static int
+symtable_handle_comprehension(struct symtable *st, expr_ty e,
+                              identifier scope_name, asdl_seq *generators,
+                              expr_ty elt, expr_ty value)
+{
+    int is_generator = (e->kind == GeneratorExp_kind);
+    int needs_tmp = !is_generator;
+    comprehension_ty outermost = ((comprehension_ty)
+                                    asdl_seq_GET(generators, 0));
+    /* Outermost iterator is evaluated in current scope */
+    VISIT(st, expr, outermost->iter);
+    /* Create comprehension scope for the rest */
+    if (!scope_name ||
+        !symtable_enter_block(st, scope_name, FunctionBlock, (void *)e, 0)) {
+        return 0;
+    }
+    /* In order to check for yield expressions under '-3', we clear
+       the generator flag, and restore it at the end */
+    is_generator |= st->st_cur->ste_generator;
+    st->st_cur->ste_generator = 0;
+    /* Outermost iter is received as an argument */
+    if (!symtable_implicit_arg(st, 0)) {
+        symtable_exit_block(st, (void *)e);
+        return 0;
+    }
+    /* Allocate temporary name if needed */
+    if (needs_tmp && !symtable_new_tmpname(st)) {
+        symtable_exit_block(st, (void *)e);
+        return 0;
+    }
+    VISIT_IN_BLOCK(st, expr, outermost->target, (void*)e);
+    VISIT_SEQ_IN_BLOCK(st, expr, outermost->ifs, (void*)e);
+    VISIT_SEQ_TAIL_IN_BLOCK(st, comprehension,
+                            generators, 1, (void*)e);
+    if (value)
+        VISIT_IN_BLOCK(st, expr, value, (void*)e);
+    VISIT_IN_BLOCK(st, expr, elt, (void*)e);
+    if (Py_Py3kWarningFlag && st->st_cur->ste_generator) {
+        const char *msg = (
+            (e->kind == SetComp_kind) ? "'yield' inside set comprehension" :
+            (e->kind == DictComp_kind) ? "'yield' inside dict comprehension" :
+            "'yield' inside generator expression");
+        if (!symtable_warn(st, PyExc_DeprecationWarning, msg, -1)) {
+            symtable_exit_block(st, (void *)e);
+            return 0;
+        }
+    }
+    st->st_cur->ste_generator |= is_generator;
+    return symtable_exit_block(st, (void *)e);
+}
+
+static int
+symtable_visit_listcomp(struct symtable *st, expr_ty e)
+{
+    asdl_seq *generators = e->v.ListComp.generators;
+    int i, is_generator;
+    /* In order to check for yield expressions under '-3', we clear
+       the generator flag, and restore it at the end */
+    is_generator = st->st_cur->ste_generator;
+    st->st_cur->ste_generator = 0;
+    VISIT(st, expr, e->v.ListComp.elt);
+    for (i = 0; i < asdl_seq_LEN(generators); i++) {
+        comprehension_ty lc = (comprehension_ty)asdl_seq_GET(generators, i);
+        VISIT(st, expr, lc->target);
+        if (i == 0 && !st->st_cur->ste_generator) {
+            /* 'yield' in the outermost iterator doesn't cause a warning */
+            VISIT(st, expr, lc->iter);
+            is_generator |= st->st_cur->ste_generator;
+            st->st_cur->ste_generator = 0;
+        }
+        else {
+            VISIT(st, expr, lc->iter);
+        }
+        VISIT_SEQ(st, expr, lc->ifs);
+    }
+
+    if (Py_Py3kWarningFlag && st->st_cur->ste_generator) {
+        const char *msg = "'yield' inside list comprehension";
+        if (!symtable_warn(st, PyExc_DeprecationWarning, msg, -1)) {
+            return 0;
+        }
+    }
+    st->st_cur->ste_generator |= is_generator;
+    return 1;
+}
+
+static int
+symtable_visit_genexp(struct symtable *st, expr_ty e)
+{
+    return symtable_handle_comprehension(st, e, GET_IDENTIFIER(genexpr),
+                                         e->v.GeneratorExp.generators,
+                                         e->v.GeneratorExp.elt, NULL);
+}
+
+static int
+symtable_visit_setcomp(struct symtable *st, expr_ty e)
+{
+    return symtable_handle_comprehension(st, e, GET_IDENTIFIER(setcomp),
+                                         e->v.SetComp.generators,
+                                         e->v.SetComp.elt, NULL);
+}
+
+static int
+symtable_visit_dictcomp(struct symtable *st, expr_ty e)
+{
+    return symtable_handle_comprehension(st, e, GET_IDENTIFIER(dictcomp),
+                                         e->v.DictComp.generators,
+                                         e->v.DictComp.key,
+                                         e->v.DictComp.value);
+}