add hg and python

1 files changed, 4570 insertions, 0 deletions

diff --git a/sys/src/cmd/python/Python/compile.c b/sys/src/cmd/python/Python/compile.c
new file mode 100644
index 000000000..e493beb6c
--- /dev/null
+++ b/sys/src/cmd/python/Python/compile.c
@@ -0,0 +1,4570 @@
+/*
+ * This file compiles an abstract syntax tree (AST) into Python bytecode.
+ *
+ * The primary entry point is PyAST_Compile(), which returns a
+ * PyCodeObject.  The compiler makes several passes to build the code
+ * object:
+ *   1. Checks for future statements.  See future.c
+ *   2. Builds a symbol table.	See symtable.c.
+ *   3. Generate code for basic blocks.	 See compiler_mod() in this file.
+ *   4. Assemble the basic blocks into final code.  See assemble() in
+ *   this file.	 
+ *
+ * Note that compiler_mod() suggests module, but the module ast type
+ * (mod_ty) has cases for expressions and interactive statements.
+ *
+ * CAUTION: The VISIT_* macros abort the current function when they
+ * encounter a problem. So don't invoke them when there is memory
+ * which needs to be released. Code blocks are OK, as the compiler
+ * structure takes care of releasing those.
+ */
+
+#include "Python.h"
+
+#include "Python-ast.h"
+#include "node.h"
+#include "pyarena.h"
+#include "ast.h"
+#include "code.h"
+#include "compile.h"
+#include "symtable.h"
+#include "opcode.h"
+
+int Py_OptimizeFlag = 0;
+
+/*
+  ISSUES:
+
+  opcode_stack_effect() function should be reviewed since stack depth bugs
+  could be really hard to find later.
+
+  Dead code is being generated (i.e. after unconditional jumps).
+    XXX(nnorwitz): not sure this is still true
+*/
+
+#define DEFAULT_BLOCK_SIZE 16
+#define DEFAULT_BLOCKS 8
+#define DEFAULT_CODE_SIZE 128
+#define DEFAULT_LNOTAB_SIZE 16
+
+struct instr {
+	unsigned i_jabs : 1;
+	unsigned i_jrel : 1;
+	unsigned i_hasarg : 1;
+	unsigned char i_opcode;
+	int i_oparg;
+	struct basicblock_ *i_target; /* target block (if jump instruction) */
+	int i_lineno;
+};
+
+typedef struct basicblock_ {
+    /* Each basicblock in a compilation unit is linked via b_list in the
+       reverse order that the block are allocated.  b_list points to the next
+       block, not to be confused with b_next, which is next by control flow. */
+	struct basicblock_ *b_list;
+	/* number of instructions used */
+	int b_iused;
+	/* length of instruction array (b_instr) */
+	int b_ialloc;
+	/* pointer to an array of instructions, initially NULL */
+	struct instr *b_instr;
+	/* If b_next is non-NULL, it is a pointer to the next
+	   block reached by normal control flow. */
+	struct basicblock_ *b_next;
+	/* b_seen is used to perform a DFS of basicblocks. */
+	unsigned b_seen : 1;
+	/* b_return is true if a RETURN_VALUE opcode is inserted. */
+	unsigned b_return : 1;
+	/* depth of stack upon entry of block, computed by stackdepth() */
+	int b_startdepth;
+	/* instruction offset for block, computed by assemble_jump_offsets() */
+	int b_offset;
+} basicblock;
+
+/* fblockinfo tracks the current frame block.
+
+A frame block is used to handle loops, try/except, and try/finally.
+It's called a frame block to distinguish it from a basic block in the
+compiler IR.
+*/
+
+enum fblocktype { LOOP, EXCEPT, FINALLY_TRY, FINALLY_END };
+
+struct fblockinfo {
+	enum fblocktype fb_type;
+	basicblock *fb_block;
+};
+
+/* The following items change on entry and exit of code blocks.
+   They must be saved and restored when returning to a block.
+*/
+struct compiler_unit {
+	PySTEntryObject *u_ste;
+
+	PyObject *u_name;
+	/* The following fields are dicts that map objects to
+	   the index of them in co_XXX.	 The index is used as
+	   the argument for opcodes that refer to those collections.
+	*/
+	PyObject *u_consts;    /* all constants */
+	PyObject *u_names;     /* all names */
+	PyObject *u_varnames;  /* local variables */
+	PyObject *u_cellvars;  /* cell variables */
+	PyObject *u_freevars;  /* free variables */
+
+	PyObject *u_private;	/* for private name mangling */
+
+	int u_argcount;	   /* number of arguments for block */ 
+    /* Pointer to the most recently allocated block.  By following b_list
+       members, you can reach all early allocated blocks. */
+	basicblock *u_blocks;
+	basicblock *u_curblock; /* pointer to current block */
+	int u_tmpname;	   /* temporary variables for list comps */
+
+	int u_nfblocks;
+	struct fblockinfo u_fblock[CO_MAXBLOCKS];
+
+	int u_firstlineno; /* the first lineno of the block */
+	int u_lineno;	   /* the lineno for the current stmt */
+	bool u_lineno_set; /* boolean to indicate whether instr
+			      has been generated with current lineno */
+};
+
+/* This struct captures the global state of a compilation.  
+
+The u pointer points to the current compilation unit, while units
+for enclosing blocks are stored in c_stack.	The u and c_stack are
+managed by compiler_enter_scope() and compiler_exit_scope().
+*/
+
+struct compiler {
+	const char *c_filename;
+	struct symtable *c_st;
+	PyFutureFeatures *c_future; /* pointer to module's __future__ */
+	PyCompilerFlags *c_flags;
+
+	int c_interactive;	 /* true if in interactive mode */
+	int c_nestlevel;
+
+	struct compiler_unit *u; /* compiler state for current block */
+	PyObject *c_stack;	 /* Python list holding compiler_unit ptrs */
+	char *c_encoding;	 /* source encoding (a borrowed reference) */
+	PyArena *c_arena;	 /* pointer to memory allocation arena */
+};
+
+struct assembler {
+	PyObject *a_bytecode;  /* string containing bytecode */
+	int a_offset;	       /* offset into bytecode */
+	int a_nblocks;	       /* number of reachable blocks */
+	basicblock **a_postorder; /* list of blocks in dfs postorder */
+	PyObject *a_lnotab;    /* string containing lnotab */
+	int a_lnotab_off;      /* offset into lnotab */
+	int a_lineno;	       /* last lineno of emitted instruction */
+	int a_lineno_off;      /* bytecode offset of last lineno */
+};
+
+static int compiler_enter_scope(struct compiler *, identifier, void *, int);
+static void compiler_free(struct compiler *);
+static basicblock *compiler_new_block(struct compiler *);
+static int compiler_next_instr(struct compiler *, basicblock *);
+static int compiler_addop(struct compiler *, int);
+static int compiler_addop_o(struct compiler *, int, PyObject *, PyObject *);
+static int compiler_addop_i(struct compiler *, int, int);
+static int compiler_addop_j(struct compiler *, int, basicblock *, int);
+static basicblock *compiler_use_new_block(struct compiler *);
+static int compiler_error(struct compiler *, const char *);
+static int compiler_nameop(struct compiler *, identifier, expr_context_ty);
+
+static PyCodeObject *compiler_mod(struct compiler *, mod_ty);
+static int compiler_visit_stmt(struct compiler *, stmt_ty);
+static int compiler_visit_keyword(struct compiler *, keyword_ty);
+static int compiler_visit_expr(struct compiler *, expr_ty);
+static int compiler_augassign(struct compiler *, stmt_ty);
+static int compiler_visit_slice(struct compiler *, slice_ty,
+				expr_context_ty);
+
+static int compiler_push_fblock(struct compiler *, enum fblocktype,
+				basicblock *);
+static void compiler_pop_fblock(struct compiler *, enum fblocktype,
+				basicblock *);
+/* Returns true if there is a loop on the fblock stack. */
+static int compiler_in_loop(struct compiler *);
+
+static int inplace_binop(struct compiler *, operator_ty);
+static int expr_constant(expr_ty e);
+
+static int compiler_with(struct compiler *, stmt_ty);
+
+static PyCodeObject *assemble(struct compiler *, int addNone);
+static PyObject *__doc__;
+
+PyObject *
+_Py_Mangle(PyObject *privateobj, PyObject *ident)
+{
+	/* Name mangling: __private becomes _classname__private.
+	   This is independent from how the name is used. */
+	const char *p, *name = PyString_AsString(ident);
+	char *buffer;
+	size_t nlen, plen;
+	if (privateobj == NULL || !PyString_Check(privateobj) ||
+	    name == NULL || name[0] != '_' || name[1] != '_') {
+		Py_INCREF(ident);
+		return ident;
+	}
+	p = PyString_AsString(privateobj);
+	nlen = strlen(name);
+	if (name[nlen-1] == '_' && name[nlen-2] == '_') {
+		Py_INCREF(ident);
+		return ident; /* Don't mangle __whatever__ */
+	}
+	/* Strip leading underscores from class name */
+	while (*p == '_')
+		p++;
+	if (*p == '\0') {
+		Py_INCREF(ident);
+		return ident; /* Don't mangle if class is just underscores */
+	}
+	plen = strlen(p);
+	ident = PyString_FromStringAndSize(NULL, 1 + nlen + plen);
+	if (!ident)
+		return 0;
+	/* ident = "_" + p[:plen] + name # i.e. 1+plen+nlen bytes */
+	buffer = PyString_AS_STRING(ident);
+	buffer[0] = '_';
+	strncpy(buffer+1, p, plen);
+	strcpy(buffer+1+plen, name);
+	return ident;
+}
+
+static int
+compiler_init(struct compiler *c)
+{
+	memset(c, 0, sizeof(struct compiler));
+
+	c->c_stack = PyList_New(0);
+	if (!c->c_stack)
+		return 0;
+
+	return 1;
+}
+
+PyCodeObject *
+PyAST_Compile(mod_ty mod, const char *filename, PyCompilerFlags *flags,
+	      PyArena *arena)
+{
+	struct compiler c;
+	PyCodeObject *co = NULL;
+	PyCompilerFlags local_flags;
+	int merged;
+
+	if (!__doc__) {
+		__doc__ = PyString_InternFromString("__doc__");
+		if (!__doc__)
+			return NULL;
+	}
+
+	if (!compiler_init(&c))
+		return NULL;
+	c.c_filename = filename;
+	c.c_arena = arena;
+	c.c_future = PyFuture_FromAST(mod, filename);
+	if (c.c_future == NULL)
+		goto finally;
+	if (!flags) {
+		local_flags.cf_flags = 0;
+		flags = &local_flags;
+	}
+	merged = c.c_future->ff_features | flags->cf_flags;
+	c.c_future->ff_features = merged;
+	flags->cf_flags = merged;
+	c.c_flags = flags;
+	c.c_nestlevel = 0;
+
+	c.c_st = PySymtable_Build(mod, filename, c.c_future);
+	if (c.c_st == NULL) {
+		if (!PyErr_Occurred())
+			PyErr_SetString(PyExc_SystemError, "no symtable");
+		goto finally;
+	}
+
+	/* XXX initialize to NULL for now, need to handle */
+	c.c_encoding = NULL;
+
+	co = compiler_mod(&c, mod);
+
+ finally:
+	compiler_free(&c);
+	assert(co || PyErr_Occurred());
+	return co;
+}
+
+PyCodeObject *
+PyNode_Compile(struct _node *n, const char *filename)
+{
+	PyCodeObject *co = NULL;
+	mod_ty mod;
+	PyArena *arena = PyArena_New();
+	if (!arena)
+		return NULL;
+	mod = PyAST_FromNode(n, NULL, filename, arena);
+	if (mod)
+		co = PyAST_Compile(mod, filename, NULL, arena);
+	PyArena_Free(arena);
+	return co;
+}
+
+static void
+compiler_free(struct compiler *c)
+{
+	if (c->c_st)
+		PySymtable_Free(c->c_st);
+	if (c->c_future)
+		PyObject_Free(c->c_future);
+	Py_DECREF(c->c_stack);
+}
+
+static PyObject *
+list2dict(PyObject *list)
+{
+	Py_ssize_t i, n;
+	PyObject *v, *k;
+	PyObject *dict = PyDict_New();
+	if (!dict) return NULL;
+
+	n = PyList_Size(list);
+	for (i = 0; i < n; i++) {
+		v = PyInt_FromLong(i);
+		if (!v) {
+			Py_DECREF(dict);
+			return NULL;
+		}
+		k = PyList_GET_ITEM(list, i);
+		k = PyTuple_Pack(2, k, k->ob_type);
+		if (k == NULL || PyDict_SetItem(dict, k, v) < 0) {
+			Py_XDECREF(k);
+			Py_DECREF(v);
+			Py_DECREF(dict);
+			return NULL;
+		}
+		Py_DECREF(k);
+		Py_DECREF(v);
+	}
+	return dict;
+}
+
+/* Return new dict containing names from src that match scope(s).
+
+src is a symbol table dictionary.  If the scope of a name matches
+either scope_type or flag is set, insert it into the new dict.	The
+values are integers, starting at offset and increasing by one for
+each key.
+*/
+
+static PyObject *
+dictbytype(PyObject *src, int scope_type, int flag, int offset)
+{
+	Py_ssize_t pos = 0, i = offset, scope;
+	PyObject *k, *v, *dest = PyDict_New();
+
+	assert(offset >= 0);
+	if (dest == NULL)
+		return NULL;
+
+	while (PyDict_Next(src, &pos, &k, &v)) {
+		/* XXX this should probably be a macro in symtable.h */
+		assert(PyInt_Check(v));
+		scope = (PyInt_AS_LONG(v) >> SCOPE_OFF) & SCOPE_MASK;
+
+		if (scope == scope_type || PyInt_AS_LONG(v) & flag) {
+			PyObject *tuple, *item = PyInt_FromLong(i);
+			if (item == NULL) {
+				Py_DECREF(dest);
+				return NULL;
+			}
+			i++;
+			tuple = PyTuple_Pack(2, k, k->ob_type);
+			if (!tuple || PyDict_SetItem(dest, tuple, item) < 0) {
+				Py_DECREF(item);
+				Py_DECREF(dest);
+				Py_XDECREF(tuple);
+				return NULL;
+			}
+			Py_DECREF(item);
+			Py_DECREF(tuple);
+		}
+	}
+	return dest;
+}
+
+/* Begin: Peephole optimizations ----------------------------------------- */
+
+#define GETARG(arr, i) ((int)((arr[i+2]<<8) + arr[i+1]))
+#define UNCONDITIONAL_JUMP(op)	(op==JUMP_ABSOLUTE || op==JUMP_FORWARD)
+#define ABSOLUTE_JUMP(op) (op==JUMP_ABSOLUTE || op==CONTINUE_LOOP)
+#define GETJUMPTGT(arr, i) (GETARG(arr,i) + (ABSOLUTE_JUMP(arr[i]) ? 0 : i+3))
+#define SETARG(arr, i, val) arr[i+2] = val>>8; arr[i+1] = val & 255
+#define CODESIZE(op)  (HAS_ARG(op) ? 3 : 1)
+#define ISBASICBLOCK(blocks, start, bytes) \
+	(blocks[start]==blocks[start+bytes-1])
+
+/* Replace LOAD_CONST c1. LOAD_CONST c2 ... LOAD_CONST cn BUILD_TUPLE n
+   with	   LOAD_CONST (c1, c2, ... cn).
+   The consts table must still be in list form so that the
+   new constant (c1, c2, ... cn) can be appended.
+   Called with codestr pointing to the first LOAD_CONST.
+   Bails out with no change if one or more of the LOAD_CONSTs is missing. 
+   Also works for BUILD_LIST when followed by an "in" or "not in" test.
+*/
+static int
+tuple_of_constants(unsigned char *codestr, int n, PyObject *consts)
+{
+	PyObject *newconst, *constant;
+	Py_ssize_t i, arg, len_consts;
+
+	/* Pre-conditions */
+	assert(PyList_CheckExact(consts));
+	assert(codestr[n*3] == BUILD_TUPLE || codestr[n*3] == BUILD_LIST);
+	assert(GETARG(codestr, (n*3)) == n);
+	for (i=0 ; i<n ; i++)
+		assert(codestr[i*3] == LOAD_CONST);
+
+	/* Buildup new tuple of constants */
+	newconst = PyTuple_New(n);
+	if (newconst == NULL)
+		return 0;
+	len_consts = PyList_GET_SIZE(consts);
+	for (i=0 ; i<n ; i++) {
+		arg = GETARG(codestr, (i*3));
+		assert(arg < len_consts);
+		constant = PyList_GET_ITEM(consts, arg);
+		Py_INCREF(constant);
+		PyTuple_SET_ITEM(newconst, i, constant);
+	}
+
+	/* Append folded constant onto consts */
+	if (PyList_Append(consts, newconst)) {
+		Py_DECREF(newconst);
+		return 0;
+	}
+	Py_DECREF(newconst);
+
+	/* Write NOPs over old LOAD_CONSTS and
+	   add a new LOAD_CONST newconst on top of the BUILD_TUPLE n */
+	memset(codestr, NOP, n*3);
+	codestr[n*3] = LOAD_CONST;
+	SETARG(codestr, (n*3), len_consts);
+	return 1;
+}
+
+/* Replace LOAD_CONST c1. LOAD_CONST c2 BINOP
+   with	   LOAD_CONST binop(c1,c2)
+   The consts table must still be in list form so that the
+   new constant can be appended.
+   Called with codestr pointing to the first LOAD_CONST. 
+   Abandons the transformation if the folding fails (i.e.  1+'a').  
+   If the new constant is a sequence, only folds when the size
+   is below a threshold value.	That keeps pyc files from
+   becoming large in the presence of code like:	 (None,)*1000.
+*/
+static int
+fold_binops_on_constants(unsigned char *codestr, PyObject *consts)
+{
+	PyObject *newconst, *v, *w;
+	Py_ssize_t len_consts, size;
+	int opcode;
+
+	/* Pre-conditions */
+	assert(PyList_CheckExact(consts));
+	assert(codestr[0] == LOAD_CONST);
+	assert(codestr[3] == LOAD_CONST);
+
+	/* Create new constant */
+	v = PyList_GET_ITEM(consts, GETARG(codestr, 0));
+	w = PyList_GET_ITEM(consts, GETARG(codestr, 3));
+	opcode = codestr[6];
+	switch (opcode) {
+		case BINARY_POWER:
+			newconst = PyNumber_Power(v, w, Py_None);
+			break;
+		case BINARY_MULTIPLY:
+			newconst = PyNumber_Multiply(v, w);
+			break;
+		case BINARY_DIVIDE:
+			/* Cannot fold this operation statically since
+                           the result can depend on the run-time presence
+                           of the -Qnew flag */
+			return 0;
+		case BINARY_TRUE_DIVIDE:
+			newconst = PyNumber_TrueDivide(v, w);
+			break;
+		case BINARY_FLOOR_DIVIDE:
+			newconst = PyNumber_FloorDivide(v, w);
+			break;
+		case BINARY_MODULO:
+			newconst = PyNumber_Remainder(v, w);
+			break;
+		case BINARY_ADD:
+			newconst = PyNumber_Add(v, w);
+			break;
+		case BINARY_SUBTRACT:
+			newconst = PyNumber_Subtract(v, w);
+			break;
+		case BINARY_SUBSCR:
+			newconst = PyObject_GetItem(v, w);
+			break;
+		case BINARY_LSHIFT:
+			newconst = PyNumber_Lshift(v, w);
+			break;
+		case BINARY_RSHIFT:
+			newconst = PyNumber_Rshift(v, w);
+			break;
+		case BINARY_AND:
+			newconst = PyNumber_And(v, w);
+			break;
+		case BINARY_XOR:
+			newconst = PyNumber_Xor(v, w);
+			break;
+		case BINARY_OR:
+			newconst = PyNumber_Or(v, w);
+			break;
+		default:
+			/* Called with an unknown opcode */
+			PyErr_Format(PyExc_SystemError,
+			     "unexpected binary operation %d on a constant",
+				     opcode);
+			return 0;
+	}
+	if (newconst == NULL) {
+		PyErr_Clear();
+		return 0;
+	}
+	size = PyObject_Size(newconst);
+	if (size == -1)
+		PyErr_Clear();
+	else if (size > 20) {
+		Py_DECREF(newconst);
+		return 0;
+	}
+
+	/* Append folded constant into consts table */
+	len_consts = PyList_GET_SIZE(consts);
+	if (PyList_Append(consts, newconst)) {
+		Py_DECREF(newconst);
+		return 0;
+	}
+	Py_DECREF(newconst);
+
+	/* Write NOP NOP NOP NOP LOAD_CONST newconst */
+	memset(codestr, NOP, 4);
+	codestr[4] = LOAD_CONST;
+	SETARG(codestr, 4, len_consts);
+	return 1;
+}
+
+static int
+fold_unaryops_on_constants(unsigned char *codestr, PyObject *consts)
+{
+	PyObject *newconst=NULL, *v;
+	Py_ssize_t len_consts;
+	int opcode;
+
+	/* Pre-conditions */
+	assert(PyList_CheckExact(consts));
+	assert(codestr[0] == LOAD_CONST);
+
+	/* Create new constant */
+	v = PyList_GET_ITEM(consts, GETARG(codestr, 0));
+	opcode = codestr[3];
+	switch (opcode) {
+		case UNARY_NEGATIVE:
+			/* Preserve the sign of -0.0 */
+			if (PyObject_IsTrue(v) == 1)
+				newconst = PyNumber_Negative(v);
+			break;
+		case UNARY_CONVERT:
+			newconst = PyObject_Repr(v);
+			break;
+		case UNARY_INVERT:
+			newconst = PyNumber_Invert(v);
+			break;
+		default:
+			/* Called with an unknown opcode */
+			PyErr_Format(PyExc_SystemError,
+			     "unexpected unary operation %d on a constant",
+				     opcode);
+			return 0;
+	}
+	if (newconst == NULL) {
+		PyErr_Clear();
+		return 0;
+	}
+
+	/* Append folded constant into consts table */
+	len_consts = PyList_GET_SIZE(consts);
+	if (PyList_Append(consts, newconst)) {
+		Py_DECREF(newconst);
+		return 0;
+	}
+	Py_DECREF(newconst);
+
+	/* Write NOP LOAD_CONST newconst */
+	codestr[0] = NOP;
+	codestr[1] = LOAD_CONST;
+	SETARG(codestr, 1, len_consts);
+	return 1;
+}
+
+static unsigned int *
+markblocks(unsigned char *code, int len)
+{
+	unsigned int *blocks = (unsigned int *)PyMem_Malloc(len*sizeof(int));
+	int i,j, opcode, blockcnt = 0;
+
+	if (blocks == NULL) {
+		PyErr_NoMemory();
+		return NULL;
+	}
+	memset(blocks, 0, len*sizeof(int));
+
+	/* Mark labels in the first pass */
+	for (i=0 ; i<len ; i+=CODESIZE(opcode)) {
+		opcode = code[i];
+		switch (opcode) {
+			case FOR_ITER:
+			case JUMP_FORWARD:
+			case JUMP_IF_FALSE:
+			case JUMP_IF_TRUE:
+			case JUMP_ABSOLUTE:
+			case CONTINUE_LOOP:
+			case SETUP_LOOP:
+			case SETUP_EXCEPT:
+			case SETUP_FINALLY:
+				j = GETJUMPTGT(code, i);
+				blocks[j] = 1;
+				break;
+		}
+	}
+	/* Build block numbers in the second pass */
+	for (i=0 ; i<len ; i++) {
+		blockcnt += blocks[i];	/* increment blockcnt over labels */
+		blocks[i] = blockcnt;
+	}
+	return blocks;
+}
+
+/* Perform basic peephole optimizations to components of a code object.
+   The consts object should still be in list form to allow new constants 
+   to be appended.
+
+   To keep the optimizer simple, it bails out (does nothing) for code
+   containing extended arguments or that has a length over 32,700.  That 
+   allows us to avoid overflow and sign issues.	 Likewise, it bails when
+   the lineno table has complex encoding for gaps >= 255.
+
+   Optimizations are restricted to simple transformations occuring within a
+   single basic block.	All transformations keep the code size the same or 
+   smaller.  For those that reduce size, the gaps are initially filled with 
+   NOPs.  Later those NOPs are removed and the jump addresses retargeted in 
+   a single pass.  Line numbering is adjusted accordingly. */
+
+static PyObject *
+optimize_code(PyObject *code, PyObject* consts, PyObject *names,
+              PyObject *lineno_obj)
+{
+	Py_ssize_t i, j, codelen;
+	int nops, h, adj;
+	int tgt, tgttgt, opcode;
+	unsigned char *codestr = NULL;
+	unsigned char *lineno;
+	int *addrmap = NULL;
+	int new_line, cum_orig_line, last_line, tabsiz;
+	int cumlc=0, lastlc=0;	/* Count runs of consecutive LOAD_CONSTs */
+	unsigned int *blocks = NULL;
+	char *name;
+
+	/* Bail out if an exception is set */
+	if (PyErr_Occurred())
+		goto exitUnchanged;
+
+	/* Bypass optimization when the lineno table is too complex */
+	assert(PyString_Check(lineno_obj));
+	lineno = (unsigned char*)PyString_AS_STRING(lineno_obj);
+	tabsiz = PyString_GET_SIZE(lineno_obj);
+	if (memchr(lineno, 255, tabsiz) != NULL)
+		goto exitUnchanged;
+
+	/* Avoid situations where jump retargeting could overflow */
+	assert(PyString_Check(code));
+	codelen = PyString_Size(code);
+	if (codelen > 32700)
+		goto exitUnchanged;
+
+	/* Make a modifiable copy of the code string */
+	codestr = (unsigned char *)PyMem_Malloc(codelen);
+	if (codestr == NULL)
+		goto exitUnchanged;
+	codestr = (unsigned char *)memcpy(codestr, 
+                                        PyString_AS_STRING(code), codelen);
+
+	/* Verify that RETURN_VALUE terminates the codestring.	This allows
+	   the various transformation patterns to look ahead several
+	   instructions without additional checks to make sure they are not
+	   looking beyond the end of the code string.
+	*/
+	if (codestr[codelen-1] != RETURN_VALUE)
+		goto exitUnchanged;
+
+	/* Mapping to new jump targets after NOPs are removed */
+	addrmap = (int *)PyMem_Malloc(codelen * sizeof(int));
+	if (addrmap == NULL)
+		goto exitUnchanged;
+
+	blocks = markblocks(codestr, codelen);
+	if (blocks == NULL)
+		goto exitUnchanged;
+	assert(PyList_Check(consts));
+
+	for (i=0 ; i<codelen ; i += CODESIZE(codestr[i])) {
+		opcode = codestr[i];
+
+		lastlc = cumlc;
+		cumlc = 0;
+
+		switch (opcode) {
+
+			/* Replace UNARY_NOT JUMP_IF_FALSE POP_TOP with 
+			   with	   JUMP_IF_TRUE POP_TOP */
+			case UNARY_NOT:
+				if (codestr[i+1] != JUMP_IF_FALSE  ||
+				    codestr[i+4] != POP_TOP  ||
+				    !ISBASICBLOCK(blocks,i,5))
+					continue;
+				tgt = GETJUMPTGT(codestr, (i+1));
+				if (codestr[tgt] != POP_TOP)
+					continue;
+				j = GETARG(codestr, i+1) + 1;
+				codestr[i] = JUMP_IF_TRUE;
+				SETARG(codestr, i, j);
+				codestr[i+3] = POP_TOP;
+				codestr[i+4] = NOP;
+				break;
+
+				/* not a is b -->  a is not b
+				   not a in b -->  a not in b
+				   not a is not b -->  a is b
+				   not a not in b -->  a in b
+				*/
+			case COMPARE_OP:
+				j = GETARG(codestr, i);
+				if (j < 6  ||  j > 9  ||
+				    codestr[i+3] != UNARY_NOT  || 
+				    !ISBASICBLOCK(blocks,i,4))
+					continue;
+				SETARG(codestr, i, (j^1));
+				codestr[i+3] = NOP;
+				break;
+
+				/* Replace LOAD_GLOBAL/LOAD_NAME None
+                                   with LOAD_CONST None */
+			case LOAD_NAME:
+			case LOAD_GLOBAL:
+				j = GETARG(codestr, i);
+				name = PyString_AsString(PyTuple_GET_ITEM(names, j));
+				if (name == NULL  ||  strcmp(name, "None") != 0)
+					continue;
+				for (j=0 ; j < PyList_GET_SIZE(consts) ; j++) {
+					if (PyList_GET_ITEM(consts, j) == Py_None)
+						break;
+				}
+				if (j == PyList_GET_SIZE(consts)) {
+					if (PyList_Append(consts, Py_None) == -1)
+					        goto exitUnchanged;                                        
+				}
+				assert(PyList_GET_ITEM(consts, j) == Py_None);
+				codestr[i] = LOAD_CONST;
+				SETARG(codestr, i, j);
+				cumlc = lastlc + 1;
+				break;
+
+				/* Skip over LOAD_CONST trueconst
+                                   JUMP_IF_FALSE xx  POP_TOP */
+			case LOAD_CONST:
+				cumlc = lastlc + 1;
+				j = GETARG(codestr, i);
+				if (codestr[i+3] != JUMP_IF_FALSE  ||
+				    codestr[i+6] != POP_TOP  ||
+				    !ISBASICBLOCK(blocks,i,7)  ||
+				    !PyObject_IsTrue(PyList_GET_ITEM(consts, j)))
+					continue;
+				memset(codestr+i, NOP, 7);
+				cumlc = 0;
+				break;
+
+				/* Try to fold tuples of constants (includes a case for lists
+				   which are only used for "in" and "not in" tests).
+				   Skip over BUILD_SEQN 1 UNPACK_SEQN 1.
+				   Replace BUILD_SEQN 2 UNPACK_SEQN 2 with ROT2.
+				   Replace BUILD_SEQN 3 UNPACK_SEQN 3 with ROT3 ROT2. */
+			case BUILD_TUPLE:
+			case BUILD_LIST:
+				j = GETARG(codestr, i);
+				h = i - 3 * j;
+				if (h >= 0  &&
+				    j <= lastlc	 &&
+				    ((opcode == BUILD_TUPLE && 
+				      ISBASICBLOCK(blocks, h, 3*(j+1))) ||
+				     (opcode == BUILD_LIST && 
+				      codestr[i+3]==COMPARE_OP && 
+				      ISBASICBLOCK(blocks, h, 3*(j+2)) &&
+				      (GETARG(codestr,i+3)==6 ||
+				       GETARG(codestr,i+3)==7))) &&
+				    tuple_of_constants(&codestr[h], j, consts)) {
+					assert(codestr[i] == LOAD_CONST);
+					cumlc = 1;
+					break;
+				}
+				if (codestr[i+3] != UNPACK_SEQUENCE  ||
+				    !ISBASICBLOCK(blocks,i,6) ||
+				    j != GETARG(codestr, i+3))
+					continue;
+				if (j == 1) {
+					memset(codestr+i, NOP, 6);
+				} else if (j == 2) {
+					codestr[i] = ROT_TWO;
+					memset(codestr+i+1, NOP, 5);
+				} else if (j == 3) {
+					codestr[i] = ROT_THREE;
+					codestr[i+1] = ROT_TWO;
+					memset(codestr+i+2, NOP, 4);
+				}
+				break;
+
+				/* Fold binary ops on constants.
+				   LOAD_CONST c1 LOAD_CONST c2 BINOP -->  LOAD_CONST binop(c1,c2) */
+			case BINARY_POWER:
+			case BINARY_MULTIPLY:
+			case BINARY_TRUE_DIVIDE:
+			case BINARY_FLOOR_DIVIDE:
+			case BINARY_MODULO:
+			case BINARY_ADD:
+			case BINARY_SUBTRACT:
+			case BINARY_SUBSCR:
+			case BINARY_LSHIFT:
+			case BINARY_RSHIFT:
+			case BINARY_AND:
+			case BINARY_XOR:
+			case BINARY_OR:
+				if (lastlc >= 2	 &&
+				    ISBASICBLOCK(blocks, i-6, 7)  &&
+				    fold_binops_on_constants(&codestr[i-6], consts)) {
+					i -= 2;
+					assert(codestr[i] == LOAD_CONST);
+					cumlc = 1;
+				}
+				break;
+
+				/* Fold unary ops on constants.
+				   LOAD_CONST c1  UNARY_OP -->	LOAD_CONST unary_op(c) */
+			case UNARY_NEGATIVE:
+			case UNARY_CONVERT:
+			case UNARY_INVERT:
+				if (lastlc >= 1	 &&
+				    ISBASICBLOCK(blocks, i-3, 4)  &&
+				    fold_unaryops_on_constants(&codestr[i-3], consts))	{
+					i -= 2;
+					assert(codestr[i] == LOAD_CONST);
+					cumlc = 1;
+				}
+				break;
+
+				/* Simplify conditional jump to conditional jump where the
+				   result of the first test implies the success of a similar
+				   test or the failure of the opposite test.
+				   Arises in code like:
+				   "if a and b:"
+				   "if a or b:"
+				   "a and b or c"
+				   "(a and b) and c"
+				   x:JUMP_IF_FALSE y   y:JUMP_IF_FALSE z  -->  x:JUMP_IF_FALSE z
+				   x:JUMP_IF_FALSE y   y:JUMP_IF_TRUE z	 -->  x:JUMP_IF_FALSE y+3
+				   where y+3 is the instruction following the second test.
+				*/
+			case JUMP_IF_FALSE:
+			case JUMP_IF_TRUE:
+				tgt = GETJUMPTGT(codestr, i);
+				j = codestr[tgt];
+				if (j == JUMP_IF_FALSE	||  j == JUMP_IF_TRUE) {
+					if (j == opcode) {
+						tgttgt = GETJUMPTGT(codestr, tgt) - i - 3;
+						SETARG(codestr, i, tgttgt);
+					} else {
+						tgt -= i;
+						SETARG(codestr, i, tgt);
+					}
+					break;
+				}
+				/* Intentional fallthrough */  
+
+				/* Replace jumps to unconditional jumps */
+			case FOR_ITER:
+			case JUMP_FORWARD:
+			case JUMP_ABSOLUTE:
+			case CONTINUE_LOOP:
+			case SETUP_LOOP:
+			case SETUP_EXCEPT:
+			case SETUP_FINALLY:
+				tgt = GETJUMPTGT(codestr, i);
+				if (!UNCONDITIONAL_JUMP(codestr[tgt]))
+					continue;
+				tgttgt = GETJUMPTGT(codestr, tgt);
+				if (opcode == JUMP_FORWARD) /* JMP_ABS can go backwards */
+					opcode = JUMP_ABSOLUTE;
+				if (!ABSOLUTE_JUMP(opcode))
+					tgttgt -= i + 3;     /* Calc relative jump addr */
+				if (tgttgt < 0)		  /* No backward relative jumps */
+					continue;
+				codestr[i] = opcode;
+				SETARG(codestr, i, tgttgt);
+				break;
+
+			case EXTENDED_ARG:
+				goto exitUnchanged;
+
+				/* Replace RETURN LOAD_CONST None RETURN with just RETURN */
+			case RETURN_VALUE:
+				if (i+4 >= codelen  ||
+				    codestr[i+4] != RETURN_VALUE	 ||
+				    !ISBASICBLOCK(blocks,i,5))
+					continue;
+				memset(codestr+i+1, NOP, 4);
+				break;
+		}
+	}
+
+	/* Fixup linenotab */
+	for (i=0, nops=0 ; i<codelen ; i += CODESIZE(codestr[i])) {
+		addrmap[i] = i - nops;
+		if (codestr[i] == NOP)
+			nops++;
+	}
+	cum_orig_line = 0;
+	last_line = 0;
+	for (i=0 ; i < tabsiz ; i+=2) {
+		cum_orig_line += lineno[i];
+		new_line = addrmap[cum_orig_line];
+		assert (new_line - last_line < 255);
+		lineno[i] =((unsigned char)(new_line - last_line));
+		last_line = new_line;
+	}
+
+	/* Remove NOPs and fixup jump targets */
+	for (i=0, h=0 ; i<codelen ; ) {
+		opcode = codestr[i];
+		switch (opcode) {
+			case NOP:
+				i++;
+				continue;
+
+			case JUMP_ABSOLUTE:
+			case CONTINUE_LOOP:
+				j = addrmap[GETARG(codestr, i)];
+				SETARG(codestr, i, j);
+				break;
+
+			case FOR_ITER:
+			case JUMP_FORWARD:
+			case JUMP_IF_FALSE:
+			case JUMP_IF_TRUE:
+			case SETUP_LOOP:
+			case SETUP_EXCEPT:
+			case SETUP_FINALLY:
+				j = addrmap[GETARG(codestr, i) + i + 3] - addrmap[i] - 3;
+				SETARG(codestr, i, j);
+				break;
+		}
+		adj = CODESIZE(opcode);
+		while (adj--)
+			codestr[h++] = codestr[i++];
+	}
+	assert(h + nops == codelen);
+
+	code = PyString_FromStringAndSize((char *)codestr, h);
+	PyMem_Free(addrmap);
+	PyMem_Free(codestr);
+	PyMem_Free(blocks);
+	return code;
+
+ exitUnchanged:
+	if (blocks != NULL)
+		PyMem_Free(blocks);
+	if (addrmap != NULL)
+		PyMem_Free(addrmap);
+	if (codestr != NULL)
+		PyMem_Free(codestr);
+	Py_INCREF(code);
+	return code;
+}
+
+/* End: Peephole optimizations ----------------------------------------- */
+
+/*
+
+Leave this debugging code for just a little longer.
+
+static void
+compiler_display_symbols(PyObject *name, PyObject *symbols)
+{
+PyObject *key, *value;
+int flags;
+Py_ssize_t pos = 0;
+
+fprintf(stderr, "block %s\n", PyString_AS_STRING(name));
+while (PyDict_Next(symbols, &pos, &key, &value)) {
+flags = PyInt_AsLong(value);
+fprintf(stderr, "var %s:", PyString_AS_STRING(key));
+if (flags & DEF_GLOBAL)
+fprintf(stderr, " declared_global");
+if (flags & DEF_LOCAL)
+fprintf(stderr, " local");
+if (flags & DEF_PARAM)
+fprintf(stderr, " param");
+if (flags & DEF_STAR)
+fprintf(stderr, " stararg");
+if (flags & DEF_DOUBLESTAR)
+fprintf(stderr, " starstar");
+if (flags & DEF_INTUPLE)
+fprintf(stderr, " tuple");
+if (flags & DEF_FREE)
+fprintf(stderr, " free");
+if (flags & DEF_FREE_GLOBAL)
+fprintf(stderr, " global");
+if (flags & DEF_FREE_CLASS)
+fprintf(stderr, " free/class");
+if (flags & DEF_IMPORT)
+fprintf(stderr, " import");
+fprintf(stderr, "\n");
+}
+	fprintf(stderr, "\n");
+}
+*/
+
+static void
+compiler_unit_check(struct compiler_unit *u)
+{
+	basicblock *block;
+	for (block = u->u_blocks; block != NULL; block = block->b_list) {
+		assert(block != (void *)0xcbcbcbcb);
+		assert(block != (void *)0xfbfbfbfb);
+		assert(block != (void *)0xdbdbdbdb);
+		if (block->b_instr != NULL) {
+			assert(block->b_ialloc > 0);
+			assert(block->b_iused > 0);
+			assert(block->b_ialloc >= block->b_iused);
+		}
+		else {
+			assert (block->b_iused == 0);
+			assert (block->b_ialloc == 0);
+		}
+	}
+}
+
+static void
+compiler_unit_free(struct compiler_unit *u)
+{
+	basicblock *b, *next;
+
+	compiler_unit_check(u);
+	b = u->u_blocks;
+	while (b != NULL) {
+		if (b->b_instr)
+			PyObject_Free((void *)b->b_instr);
+		next = b->b_list;
+		PyObject_Free((void *)b);
+		b = next;
+	}
+	Py_CLEAR(u->u_ste);
+	Py_CLEAR(u->u_name);
+	Py_CLEAR(u->u_consts);
+	Py_CLEAR(u->u_names);
+	Py_CLEAR(u->u_varnames);
+	Py_CLEAR(u->u_freevars);
+	Py_CLEAR(u->u_cellvars);
+	Py_CLEAR(u->u_private);
+	PyObject_Free(u);
+}
+
+static int
+compiler_enter_scope(struct compiler *c, identifier name, void *key,
+		     int lineno)
+{
+	struct compiler_unit *u;
+
+	u = (struct compiler_unit *)PyObject_Malloc(sizeof(
+                                                struct compiler_unit));
+	if (!u) {
+		PyErr_NoMemory();
+		return 0;
+	}
+	memset(u, 0, sizeof(struct compiler_unit));
+	u->u_argcount = 0;
+	u->u_ste = PySymtable_Lookup(c->c_st, key);
+	if (!u->u_ste) {
+		compiler_unit_free(u);
+		return 0;
+	}
+	Py_INCREF(name);
+	u->u_name = name;
+	u->u_varnames = list2dict(u->u_ste->ste_varnames);
+	u->u_cellvars = dictbytype(u->u_ste->ste_symbols, CELL, 0, 0);
+	if (!u->u_varnames || !u->u_cellvars) {
+		compiler_unit_free(u);
+		return 0;
+	}
+
+	u->u_freevars = dictbytype(u->u_ste->ste_symbols, FREE, DEF_FREE_CLASS,
+				   PyDict_Size(u->u_cellvars));
+	if (!u->u_freevars) {
+		compiler_unit_free(u);
+		return 0;
+	}
+
+	u->u_blocks = NULL;
+	u->u_tmpname = 0;
+	u->u_nfblocks = 0;
+	u->u_firstlineno = lineno;
+	u->u_lineno = 0;
+	u->u_lineno_set = false;
+	u->u_consts = PyDict_New();
+	if (!u->u_consts) {
+		compiler_unit_free(u);
+		return 0;
+	}
+	u->u_names = PyDict_New();
+	if (!u->u_names) {
+		compiler_unit_free(u);
+		return 0;
+	}
+
+	u->u_private = NULL;
+
+	/* Push the old compiler_unit on the stack. */
+	if (c->u) {
+		PyObject *wrapper = PyCObject_FromVoidPtr(c->u, NULL);
+		if (!wrapper || PyList_Append(c->c_stack, wrapper) < 0) {
+			Py_XDECREF(wrapper);
+			compiler_unit_free(u);
+			return 0;
+		}
+		Py_DECREF(wrapper);
+		u->u_private = c->u->u_private;
+		Py_XINCREF(u->u_private);
+	}
+	c->u = u;
+
+	c->c_nestlevel++;
+	if (compiler_use_new_block(c) == NULL)
+		return 0;
+
+	return 1;
+}
+
+static void
+compiler_exit_scope(struct compiler *c)
+{
+	int n;
+	PyObject *wrapper;
+
+	c->c_nestlevel--;
+	compiler_unit_free(c->u);
+	/* Restore c->u to the parent unit. */
+	n = PyList_GET_SIZE(c->c_stack) - 1;
+	if (n >= 0) {
+		wrapper = PyList_GET_ITEM(c->c_stack, n);
+		c->u = (struct compiler_unit *)PyCObject_AsVoidPtr(wrapper);
+		/* we are deleting from a list so this really shouldn't fail */
+		if (PySequence_DelItem(c->c_stack, n) < 0)
+			Py_FatalError("compiler_exit_scope()");
+		compiler_unit_check(c->u);
+	}
+	else
+		c->u = NULL;
+
+}
+
+/* Allocate a new "anonymous" local variable.
+   Used by list comprehensions and with statements.
+*/
+
+static PyObject *
+compiler_new_tmpname(struct compiler *c)
+{
+	char tmpname[256];
+	PyOS_snprintf(tmpname, sizeof(tmpname), "_[%d]", ++c->u->u_tmpname);
+	return PyString_FromString(tmpname);
+}
+
+/* Allocate a new block and return a pointer to it.
+   Returns NULL on error.
+*/
+
+static basicblock *
+compiler_new_block(struct compiler *c)
+{
+	basicblock *b;
+	struct compiler_unit *u;
+
+	u = c->u;
+	b = (basicblock *)PyObject_Malloc(sizeof(basicblock));
+	if (b == NULL) {
+		PyErr_NoMemory();
+		return NULL;
+	}
+	memset((void *)b, 0, sizeof(basicblock));
+    /* Extend the singly linked list of blocks with new block. */
+	b->b_list = u->u_blocks;
+	u->u_blocks = b;
+	return b;
+}
+
+static basicblock *
+compiler_use_new_block(struct compiler *c)
+{
+	basicblock *block = compiler_new_block(c);
+	if (block == NULL)
+		return NULL;
+	c->u->u_curblock = block;
+	return block;
+}
+
+static basicblock *
+compiler_next_block(struct compiler *c)
+{
+	basicblock *block = compiler_new_block(c);
+	if (block == NULL)
+		return NULL;
+	c->u->u_curblock->b_next = block;
+	c->u->u_curblock = block;
+	return block;
+}
+
+static basicblock *
+compiler_use_next_block(struct compiler *c, basicblock *block)
+{
+	assert(block != NULL);
+	c->u->u_curblock->b_next = block;
+	c->u->u_curblock = block;
+	return block;
+}
+
+/* Returns the offset of the next instruction in the current block's
+   b_instr array.  Resizes the b_instr as necessary.
+   Returns -1 on failure.
+ */
+
+static int
+compiler_next_instr(struct compiler *c, basicblock *b)
+{
+	assert(b != NULL);
+	if (b->b_instr == NULL) {
+		b->b_instr = (struct instr *)PyObject_Malloc(
+                                 sizeof(struct instr) * DEFAULT_BLOCK_SIZE);
+		if (b->b_instr == NULL) {
+			PyErr_NoMemory();
+			return -1;
+		}
+		b->b_ialloc = DEFAULT_BLOCK_SIZE;
+		memset((char *)b->b_instr, 0,
+		       sizeof(struct instr) * DEFAULT_BLOCK_SIZE);
+	}
+	else if (b->b_iused == b->b_ialloc) {
+		struct instr *tmp;
+		size_t oldsize, newsize;
+		oldsize = b->b_ialloc * sizeof(struct instr);
+		newsize = oldsize << 1;
+		if (newsize == 0) {
+			PyErr_NoMemory();
+			return -1;
+		}
+		b->b_ialloc <<= 1;
+		tmp = (struct instr *)PyObject_Realloc(
+                                                (void *)b->b_instr, newsize);
+		if (tmp == NULL) {
+			PyErr_NoMemory();
+			return -1;
+		}
+		b->b_instr = tmp;
+		memset((char *)b->b_instr + oldsize, 0, newsize - oldsize);
+	}
+	return b->b_iused++;
+}
+
+/* Set the i_lineno member of the instruction at offse off if the
+   line number for the current expression/statement (?) has not
+   already been set.  If it has been set, the call has no effect.
+
+   Every time a new node is b
+   */
+
+static void
+compiler_set_lineno(struct compiler *c, int off)
+{
+	basicblock *b;
+	if (c->u->u_lineno_set)
+		return;
+	c->u->u_lineno_set = true;
+	b = c->u->u_curblock;
+	b->b_instr[off].i_lineno = c->u->u_lineno;
+}
+
+static int
+opcode_stack_effect(int opcode, int oparg)
+{
+	switch (opcode) {
+		case POP_TOP:
+			return -1;
+		case ROT_TWO:
+		case ROT_THREE:
+			return 0;
+		case DUP_TOP:
+			return 1;
+		case ROT_FOUR:
+			return 0;
+
+		case UNARY_POSITIVE:
+		case UNARY_NEGATIVE:
+		case UNARY_NOT:
+		case UNARY_CONVERT:
+		case UNARY_INVERT:
+			return 0;
+
+		case LIST_APPEND:
+			return -2;
+
+		case BINARY_POWER:
+		case BINARY_MULTIPLY:
+		case BINARY_DIVIDE:
+		case BINARY_MODULO:
+		case BINARY_ADD:
+		case BINARY_SUBTRACT:
+		case BINARY_SUBSCR:
+		case BINARY_FLOOR_DIVIDE:
+		case BINARY_TRUE_DIVIDE:
+			return -1;
+		case INPLACE_FLOOR_DIVIDE:
+		case INPLACE_TRUE_DIVIDE:
+			return -1;
+
+		case SLICE+0:
+			return 1;
+		case SLICE+1:
+			return 0;
+		case SLICE+2:
+			return 0;
+		case SLICE+3:
+			return -1;
+
+		case STORE_SLICE+0:
+			return -2;
+		case STORE_SLICE+1:
+			return -3;
+		case STORE_SLICE+2:
+			return -3;
+		case STORE_SLICE+3:
+			return -4;
+
+		case DELETE_SLICE+0:
+			return -1;
+		case DELETE_SLICE+1:
+			return -2;
+		case DELETE_SLICE+2:
+			return -2;
+		case DELETE_SLICE+3:
+			return -3;
+
+		case INPLACE_ADD:
+		case INPLACE_SUBTRACT:
+		case INPLACE_MULTIPLY:
+		case INPLACE_DIVIDE:
+		case INPLACE_MODULO:
+			return -1;
+		case STORE_SUBSCR:
+			return -3;
+		case DELETE_SUBSCR:
+			return -2;
+
+		case BINARY_LSHIFT:
+		case BINARY_RSHIFT:
+		case BINARY_AND:
+		case BINARY_XOR:
+		case BINARY_OR:
+			return -1;
+		case INPLACE_POWER:
+			return -1;
+		case GET_ITER:
+			return 0;
+
+		case PRINT_EXPR:
+			return -1;
+		case PRINT_ITEM:
+			return -1;
+		case PRINT_NEWLINE:
+			return 0;
+		case PRINT_ITEM_TO:
+			return -2;
+		case PRINT_NEWLINE_TO:
+			return -1;
+		case INPLACE_LSHIFT:
+		case INPLACE_RSHIFT:
+		case INPLACE_AND:
+		case INPLACE_XOR:
+		case INPLACE_OR:
+			return -1;
+		case BREAK_LOOP:
+			return 0;
+		case WITH_CLEANUP:
+			return -1; /* XXX Sometimes more */
+		case LOAD_LOCALS:
+			return 1;
+		case RETURN_VALUE:
+			return -1;
+		case IMPORT_STAR:
+			return -1;
+		case EXEC_STMT:
+			return -3;
+		case YIELD_VALUE:
+			return 0;
+
+		case POP_BLOCK:
+			return 0;
+		case END_FINALLY:
+			return -1; /* or -2 or -3 if exception occurred */
+		case BUILD_CLASS:
+			return -2;
+
+		case STORE_NAME:
+			return -1;
+		case DELETE_NAME:
+			return 0;
+		case UNPACK_SEQUENCE:
+			return oparg-1;
+		case FOR_ITER:
+			return 1;
+
+		case STORE_ATTR:
+			return -2;
+		case DELETE_ATTR:
+			return -1;
+		case STORE_GLOBAL:
+			return -1;
+		case DELETE_GLOBAL:
+			return 0;
+		case DUP_TOPX:
+			return oparg;
+		case LOAD_CONST:
+			return 1;
+		case LOAD_NAME:
+			return 1;
+		case BUILD_TUPLE:
+		case BUILD_LIST:
+			return 1-oparg;
+		case BUILD_MAP:
+			return 1;
+		case LOAD_ATTR:
+			return 0;
+		case COMPARE_OP:
+			return -1;
+		case IMPORT_NAME:
+			return 0;
+		case IMPORT_FROM:
+			return 1;
+
+		case JUMP_FORWARD:
+		case JUMP_IF_FALSE:
+		case JUMP_IF_TRUE:
+		case JUMP_ABSOLUTE:
+			return 0;
+
+		case LOAD_GLOBAL:
+			return 1;
+
+		case CONTINUE_LOOP:
+			return 0;
+		case SETUP_LOOP:
+			return 0;
+		case SETUP_EXCEPT:
+		case SETUP_FINALLY:
+			return 3; /* actually pushed by an exception */
+
+		case LOAD_FAST:
+			return 1;
+		case STORE_FAST:
+			return -1;
+		case DELETE_FAST:
+			return 0;
+
+		case RAISE_VARARGS:
+			return -oparg;
+#define NARGS(o) (((o) % 256) + 2*((o) / 256))
+		case CALL_FUNCTION:
+			return -NARGS(oparg);
+		case CALL_FUNCTION_VAR:
+		case CALL_FUNCTION_KW:
+			return -NARGS(oparg)-1;
+		case CALL_FUNCTION_VAR_KW:
+			return -NARGS(oparg)-2;
+#undef NARGS
+		case MAKE_FUNCTION:
+			return -oparg;
+		case BUILD_SLICE:
+			if (oparg == 3)
+				return -2;
+			else
+				return -1;
+
+		case MAKE_CLOSURE:
+			return -oparg;
+		case LOAD_CLOSURE:
+			return 1;
+		case LOAD_DEREF:
+			return 1;
+		case STORE_DEREF:
+			return -1;
+		default:
+			fprintf(stderr, "opcode = %d\n", opcode);
+			Py_FatalError("opcode_stack_effect()");
+
+	}
+	return 0; /* not reachable */
+}
+
+/* Add an opcode with no argument.
+   Returns 0 on failure, 1 on success.
+*/
+
+static int
+compiler_addop(struct compiler *c, int opcode)
+{
+	basicblock *b;
+	struct instr *i;
+	int off;
+	off = compiler_next_instr(c, c->u->u_curblock);
+	if (off < 0)
+		return 0;
+	b = c->u->u_curblock;
+	i = &b->b_instr[off];
+	i->i_opcode = opcode;
+	i->i_hasarg = 0;
+	if (opcode == RETURN_VALUE)
+		b->b_return = 1;
+	compiler_set_lineno(c, off);
+	return 1;
+}
+
+static int
+compiler_add_o(struct compiler *c, PyObject *dict, PyObject *o)
+{
+	PyObject *t, *v;
+	Py_ssize_t arg;
+
+	/* necessary to make sure types aren't coerced (e.g., int and long) */
+	t = PyTuple_Pack(2, o, o->ob_type);
+	if (t == NULL)
+	    return -1;
+
+	v = PyDict_GetItem(dict, t);
+	if (!v) {
+		arg = PyDict_Size(dict);
+		v = PyInt_FromLong(arg);
+		if (!v) {
+			Py_DECREF(t);
+			return -1;
+		}
+		if (PyDict_SetItem(dict, t, v) < 0) {
+			Py_DECREF(t);
+			Py_DECREF(v);
+			return -1;
+		}
+		Py_DECREF(v);
+	}
+	else
+		arg = PyInt_AsLong(v);
+	Py_DECREF(t);
+	return arg;
+}
+
+static int
+compiler_addop_o(struct compiler *c, int opcode, PyObject *dict,
+		     PyObject *o)
+{
+    int arg = compiler_add_o(c, dict, o);
+    if (arg < 0)
+	return 0;
+    return compiler_addop_i(c, opcode, arg);
+}
+
+static int
+compiler_addop_name(struct compiler *c, int opcode, PyObject *dict,
+		    PyObject *o)
+{
+    int arg;
+    PyObject *mangled = _Py_Mangle(c->u->u_private, o);
+    if (!mangled)
+	return 0;
+    arg = compiler_add_o(c, dict, mangled);
+    Py_DECREF(mangled);
+    if (arg < 0)
+	return 0;
+    return compiler_addop_i(c, opcode, arg);
+}
+
+/* Add an opcode with an integer argument.
+   Returns 0 on failure, 1 on success.
+*/
+
+static int
+compiler_addop_i(struct compiler *c, int opcode, int oparg)
+{
+	struct instr *i;
+	int off;
+	off = compiler_next_instr(c, c->u->u_curblock);
+	if (off < 0)
+		return 0;
+	i = &c->u->u_curblock->b_instr[off];
+	i->i_opcode = opcode;
+	i->i_oparg = oparg;
+	i->i_hasarg = 1;
+	compiler_set_lineno(c, off);
+	return 1;
+}
+
+static int
+compiler_addop_j(struct compiler *c, int opcode, basicblock *b, int absolute)
+{
+	struct instr *i;
+	int off;
+
+	assert(b != NULL);
+	off = compiler_next_instr(c, c->u->u_curblock);
+	if (off < 0)
+		return 0;
+	i = &c->u->u_curblock->b_instr[off];
+	i->i_opcode = opcode;
+	i->i_target = b;
+	i->i_hasarg = 1;
+	if (absolute)
+		i->i_jabs = 1;
+	else
+		i->i_jrel = 1;
+	compiler_set_lineno(c, off);
+	return 1;
+}
+
+/* The distinction between NEW_BLOCK and NEXT_BLOCK is subtle.	(I'd
+   like to find better names.)	NEW_BLOCK() creates a new block and sets
+   it as the current block.  NEXT_BLOCK() also creates an implicit jump
+   from the current block to the new block.
+*/
+
+/* XXX The returns inside these macros make it impossible to decref
+   objects created in the local function.
+*/
+
+
+#define NEW_BLOCK(C) { \
+	if (compiler_use_new_block((C)) == NULL) \
+		return 0; \
+}
+
+#define NEXT_BLOCK(C) { \
+	if (compiler_next_block((C)) == NULL) \
+		return 0; \
+}
+
+#define ADDOP(C, OP) { \
+	if (!compiler_addop((C), (OP))) \
+		return 0; \
+}
+
+#define ADDOP_IN_SCOPE(C, OP) { \
+	if (!compiler_addop((C), (OP))) { \
+		compiler_exit_scope(c); \
+		return 0; \
+	} \
+}
+
+#define ADDOP_O(C, OP, O, TYPE) { \
+	if (!compiler_addop_o((C), (OP), (C)->u->u_ ## TYPE, (O))) \
+		return 0; \
+}
+
+#define ADDOP_NAME(C, OP, O, TYPE) { \
+	if (!compiler_addop_name((C), (OP), (C)->u->u_ ## TYPE, (O))) \
+		return 0; \
+}
+
+#define ADDOP_I(C, OP, O) { \
+	if (!compiler_addop_i((C), (OP), (O))) \
+		return 0; \
+}
+
+#define ADDOP_JABS(C, OP, O) { \
+	if (!compiler_addop_j((C), (OP), (O), 1)) \
+		return 0; \
+}
+
+#define ADDOP_JREL(C, OP, O) { \
+	if (!compiler_addop_j((C), (OP), (O), 0)) \
+		return 0; \
+}
+
+/* VISIT and VISIT_SEQ takes an ASDL type as their second argument.  They use
+   the ASDL name to synthesize the name of the C type and the visit function.
+*/
+
+#define VISIT(C, TYPE, V) {\
+	if (!compiler_visit_ ## TYPE((C), (V))) \
+		return 0; \
+}
+
+#define VISIT_IN_SCOPE(C, TYPE, V) {\
+	if (!compiler_visit_ ## TYPE((C), (V))) { \
+		compiler_exit_scope(c); \
+		return 0; \
+	} \
+}
+
+#define VISIT_SLICE(C, V, CTX) {\
+	if (!compiler_visit_slice((C), (V), (CTX))) \
+		return 0; \
+}
+
+#define VISIT_SEQ(C, 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 (!compiler_visit_ ## TYPE((C), elt)) \
+			return 0; \
+	} \
+}
+
+#define VISIT_SEQ_IN_SCOPE(C, 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 (!compiler_visit_ ## TYPE((C), elt)) { \
+			compiler_exit_scope(c); \
+			return 0; \
+		} \
+	} \
+}
+
+static int
+compiler_isdocstring(stmt_ty s)
+{
+    if (s->kind != Expr_kind)
+	return 0;
+    return s->v.Expr.value->kind == Str_kind;
+}
+
+/* Compile a sequence of statements, checking for a docstring. */
+
+static int
+compiler_body(struct compiler *c, asdl_seq *stmts)
+{
+	int i = 0;
+	stmt_ty st;
+
+	if (!asdl_seq_LEN(stmts))
+		return 1;
+	st = (stmt_ty)asdl_seq_GET(stmts, 0);
+	if (compiler_isdocstring(st)) {
+		i = 1;
+		VISIT(c, expr, st->v.Expr.value);
+		if (!compiler_nameop(c, __doc__, Store))
+			return 0;
+	}
+	for (; i < asdl_seq_LEN(stmts); i++)
+	    VISIT(c, stmt, (stmt_ty)asdl_seq_GET(stmts, i));
+	return 1;
+}
+
+static PyCodeObject *
+compiler_mod(struct compiler *c, mod_ty mod)
+{
+	PyCodeObject *co;
+	int addNone = 1;
+	static PyObject *module;
+	if (!module) {
+		module = PyString_FromString("<module>");
+		if (!module)
+			return NULL;
+	}
+	/* Use 0 for firstlineno initially, will fixup in assemble(). */
+	if (!compiler_enter_scope(c, module, mod, 0))
+		return NULL;
+	switch (mod->kind) {
+	case Module_kind: 
+		if (!compiler_body(c, mod->v.Module.body)) {
+			compiler_exit_scope(c);
+			return 0;
+		}
+		break;
+	case Interactive_kind:
+		c->c_interactive = 1;
+		VISIT_SEQ_IN_SCOPE(c, stmt, 
+                                        mod->v.Interactive.body);
+		break;
+	case Expression_kind:
+		VISIT_IN_SCOPE(c, expr, mod->v.Expression.body);
+		addNone = 0;
+		break;
+	case Suite_kind:
+		PyErr_SetString(PyExc_SystemError,
+				"suite should not be possible");
+		return 0;
+	default:
+		PyErr_Format(PyExc_SystemError,
+			     "module kind %d should not be possible",
+			     mod->kind);
+		return 0;
+	}
+	co = assemble(c, addNone);
+	compiler_exit_scope(c);
+	return co;
+}
+
+/* The test for LOCAL must come before the test for FREE in order to
+   handle classes where name is both local and free.  The local var is
+   a method and the free var is a free var referenced within a method.
+*/
+
+static int
+get_ref_type(struct compiler *c, PyObject *name)
+{
+	int scope = PyST_GetScope(c->u->u_ste, name);
+	if (scope == 0) {
+	    char buf[350];
+	    PyOS_snprintf(buf, sizeof(buf),
+			  "unknown scope for %.100s in %.100s(%s) in %s\n"
+			  "symbols: %s\nlocals: %s\nglobals: %s\n",
+			  PyString_AS_STRING(name), 
+			  PyString_AS_STRING(c->u->u_name), 
+			  PyObject_REPR(c->u->u_ste->ste_id),
+			  c->c_filename,
+			  PyObject_REPR(c->u->u_ste->ste_symbols),
+			  PyObject_REPR(c->u->u_varnames),
+			  PyObject_REPR(c->u->u_names)
+		);
+	    Py_FatalError(buf);
+	}
+
+	return scope;
+}
+
+static int
+compiler_lookup_arg(PyObject *dict, PyObject *name)
+{
+    PyObject *k, *v;
+    k = PyTuple_Pack(2, name, name->ob_type);
+    if (k == NULL)
+	return -1;
+    v = PyDict_GetItem(dict, k);
+    Py_DECREF(k);
+    if (v == NULL)
+	return -1;
+    return PyInt_AS_LONG(v);
+}
+
+static int
+compiler_make_closure(struct compiler *c, PyCodeObject *co, int args)
+{
+	int i, free = PyCode_GetNumFree(co);
+	if (free == 0) {
+	    ADDOP_O(c, LOAD_CONST, (PyObject*)co, consts);
+	    ADDOP_I(c, MAKE_FUNCTION, args);
+	    return 1;
+	}
+	for (i = 0; i < free; ++i) {
+		/* Bypass com_addop_varname because it will generate
+		   LOAD_DEREF but LOAD_CLOSURE is needed. 
+		*/
+		PyObject *name = PyTuple_GET_ITEM(co->co_freevars, i);
+		int arg, reftype;
+
+		/* Special case: If a class contains a method with a
+		   free variable that has the same name as a method,
+		   the name will be considered free *and* local in the
+		   class.  It should be handled by the closure, as
+		   well as by the normal name loookup logic.
+		*/
+		reftype = get_ref_type(c, name);
+		if (reftype == CELL)
+			arg = compiler_lookup_arg(c->u->u_cellvars, name);
+		else /* (reftype == FREE) */
+			arg = compiler_lookup_arg(c->u->u_freevars, name);
+		if (arg == -1) {
+			printf("lookup %s in %s %d %d\n"
+				"freevars of %s: %s\n",
+				PyObject_REPR(name), 
+				PyString_AS_STRING(c->u->u_name), 
+				reftype, arg,
+				PyString_AS_STRING(co->co_name),
+				PyObject_REPR(co->co_freevars));
+			Py_FatalError("compiler_make_closure()");
+		}
+		ADDOP_I(c, LOAD_CLOSURE, arg);
+	}
+	ADDOP_I(c, BUILD_TUPLE, free);
+	ADDOP_O(c, LOAD_CONST, (PyObject*)co, consts);
+	ADDOP_I(c, MAKE_CLOSURE, args);
+	return 1;
+}
+
+static int
+compiler_decorators(struct compiler *c, asdl_seq* decos)
+{
+	int i;
+
+	if (!decos)
+		return 1;
+
+	for (i = 0; i < asdl_seq_LEN(decos); i++) {
+		VISIT(c, expr, (expr_ty)asdl_seq_GET(decos, i));
+	}
+	return 1;
+}
+
+static int
+compiler_arguments(struct compiler *c, arguments_ty args)
+{
+	int i;
+	int n = asdl_seq_LEN(args->args);
+	/* Correctly handle nested argument lists */
+	for (i = 0; i < n; i++) {
+		expr_ty arg = (expr_ty)asdl_seq_GET(args->args, i);
+		if (arg->kind == Tuple_kind) {
+			PyObject *id = PyString_FromFormat(".%d", i);
+			if (id == NULL) {
+				return 0;
+			}
+			if (!compiler_nameop(c, id, Load)) {
+				Py_DECREF(id);
+				return 0;
+			}
+			Py_DECREF(id);
+			VISIT(c, expr, arg);
+		}
+	}
+	return 1;
+}
+
+static int
+compiler_function(struct compiler *c, stmt_ty s)
+{
+	PyCodeObject *co;
+	PyObject *first_const = Py_None;
+	arguments_ty args = s->v.FunctionDef.args;
+	asdl_seq* decos = s->v.FunctionDef.decorators;
+	stmt_ty st;
+	int i, n, docstring;
+
+	assert(s->kind == FunctionDef_kind);
+
+	if (!compiler_decorators(c, decos))
+		return 0;
+	if (args->defaults)
+		VISIT_SEQ(c, expr, args->defaults);
+	if (!compiler_enter_scope(c, s->v.FunctionDef.name, (void *)s,
+				  s->lineno))
+		return 0;
+
+	st = (stmt_ty)asdl_seq_GET(s->v.FunctionDef.body, 0);
+	docstring = compiler_isdocstring(st);
+	if (docstring)
+	    first_const = st->v.Expr.value->v.Str.s;
+	if (compiler_add_o(c, c->u->u_consts, first_const) < 0)	 {
+	    compiler_exit_scope(c);
+	    return 0;
+	}
+
+	/* unpack nested arguments */
+	compiler_arguments(c, args);
+
+	c->u->u_argcount = asdl_seq_LEN(args->args);
+	n = asdl_seq_LEN(s->v.FunctionDef.body);
+	/* if there was a docstring, we need to skip the first statement */
+	for (i = docstring; i < n; i++) {
+		st = (stmt_ty)asdl_seq_GET(s->v.FunctionDef.body, i);
+		VISIT_IN_SCOPE(c, stmt, st);
+	}
+	co = assemble(c, 1);
+	compiler_exit_scope(c);
+	if (co == NULL)
+		return 0;
+
+	compiler_make_closure(c, co, asdl_seq_LEN(args->defaults));
+	Py_DECREF(co);
+
+	for (i = 0; i < asdl_seq_LEN(decos); i++) {
+		ADDOP_I(c, CALL_FUNCTION, 1);
+	}
+
+	return compiler_nameop(c, s->v.FunctionDef.name, Store);
+}
+
+static int
+compiler_class(struct compiler *c, stmt_ty s)
+{
+	int n;
+	PyCodeObject *co;
+	PyObject *str;
+	/* push class name on stack, needed by BUILD_CLASS */
+	ADDOP_O(c, LOAD_CONST, s->v.ClassDef.name, consts);
+	/* push the tuple of base classes on the stack */
+	n = asdl_seq_LEN(s->v.ClassDef.bases);
+	if (n > 0)
+		VISIT_SEQ(c, expr, s->v.ClassDef.bases);
+	ADDOP_I(c, BUILD_TUPLE, n);
+	if (!compiler_enter_scope(c, s->v.ClassDef.name, (void *)s,
+				  s->lineno))
+		return 0;
+	c->u->u_private = s->v.ClassDef.name;
+	Py_INCREF(c->u->u_private);
+	str = PyString_InternFromString("__name__");
+	if (!str || !compiler_nameop(c, str, Load)) {
+		Py_XDECREF(str);
+		compiler_exit_scope(c);
+		return 0;
+	}
+	
+	Py_DECREF(str);
+	str = PyString_InternFromString("__module__");
+	if (!str || !compiler_nameop(c, str, Store)) {
+		Py_XDECREF(str);
+		compiler_exit_scope(c);
+		return 0;
+	}
+	Py_DECREF(str);
+
+	if (!compiler_body(c, s->v.ClassDef.body)) {
+		compiler_exit_scope(c);
+		return 0;
+	}
+
+	ADDOP_IN_SCOPE(c, LOAD_LOCALS);
+	ADDOP_IN_SCOPE(c, RETURN_VALUE);
+	co = assemble(c, 1);
+	compiler_exit_scope(c);
+	if (co == NULL)
+		return 0;
+
+	compiler_make_closure(c, co, 0);
+	Py_DECREF(co);
+
+	ADDOP_I(c, CALL_FUNCTION, 0);
+	ADDOP(c, BUILD_CLASS);
+	if (!compiler_nameop(c, s->v.ClassDef.name, Store))
+		return 0;
+	return 1;
+}
+
+static int
+compiler_ifexp(struct compiler *c, expr_ty e)
+{
+	basicblock *end, *next;
+	
+	assert(e->kind == IfExp_kind);
+	end = compiler_new_block(c);
+	if (end == NULL)
+		return 0;
+	next = compiler_new_block(c);
+	if (next == NULL)
+		return 0;
+	VISIT(c, expr, e->v.IfExp.test);
+	ADDOP_JREL(c, JUMP_IF_FALSE, next);
+	ADDOP(c, POP_TOP);
+	VISIT(c, expr, e->v.IfExp.body);
+	ADDOP_JREL(c, JUMP_FORWARD, end);
+	compiler_use_next_block(c, next);
+	ADDOP(c, POP_TOP);
+	VISIT(c, expr, e->v.IfExp.orelse);
+	compiler_use_next_block(c, end);
+	return 1;
+}
+
+static int
+compiler_lambda(struct compiler *c, expr_ty e)
+{
+	PyCodeObject *co;
+	static identifier name;
+	arguments_ty args = e->v.Lambda.args;
+	assert(e->kind == Lambda_kind);
+
+	if (!name) {
+		name = PyString_InternFromString("<lambda>");
+		if (!name)
+			return 0;
+	}
+
+	if (args->defaults)
+		VISIT_SEQ(c, expr, args->defaults);
+	if (!compiler_enter_scope(c, name, (void *)e, e->lineno))
+		return 0;
+
+	/* unpack nested arguments */
+	compiler_arguments(c, args);
+	
+	c->u->u_argcount = asdl_seq_LEN(args->args);
+	VISIT_IN_SCOPE(c, expr, e->v.Lambda.body);
+	ADDOP_IN_SCOPE(c, RETURN_VALUE);
+	co = assemble(c, 1);
+	compiler_exit_scope(c);
+	if (co == NULL)
+		return 0;
+
+	compiler_make_closure(c, co, asdl_seq_LEN(args->defaults));
+	Py_DECREF(co);
+
+	return 1;
+}
+
+static int
+compiler_print(struct compiler *c, stmt_ty s)
+{
+	int i, n;
+	bool dest;
+
+	assert(s->kind == Print_kind);
+	n = asdl_seq_LEN(s->v.Print.values);
+	dest = false;
+	if (s->v.Print.dest) {
+		VISIT(c, expr, s->v.Print.dest);
+		dest = true;
+	}
+	for (i = 0; i < n; i++) {
+		expr_ty e = (expr_ty)asdl_seq_GET(s->v.Print.values, i);
+		if (dest) {
+			ADDOP(c, DUP_TOP);
+			VISIT(c, expr, e);
+			ADDOP(c, ROT_TWO);
+			ADDOP(c, PRINT_ITEM_TO);
+		}
+		else {
+			VISIT(c, expr, e);
+			ADDOP(c, PRINT_ITEM);
+		}
+	}
+	if (s->v.Print.nl) {
+		if (dest)
+			ADDOP(c, PRINT_NEWLINE_TO)
+		else
+			ADDOP(c, PRINT_NEWLINE)
+	}
+	else if (dest)
+		ADDOP(c, POP_TOP);
+	return 1;
+}
+
+static int
+compiler_if(struct compiler *c, stmt_ty s)
+{
+	basicblock *end, *next;
+	int constant;
+	assert(s->kind == If_kind);
+	end = compiler_new_block(c);
+	if (end == NULL)
+		return 0;
+	next = compiler_new_block(c);
+	if (next == NULL)
+	    return 0;
+	
+	constant = expr_constant(s->v.If.test);
+	/* constant = 0: "if 0"
+	 * constant = 1: "if 1", "if 2", ...
+	 * constant = -1: rest */
+	if (constant == 0) {
+		if (s->v.If.orelse)
+			VISIT_SEQ(c, stmt, s->v.If.orelse);
+	} else if (constant == 1) {
+		VISIT_SEQ(c, stmt, s->v.If.body);
+	} else {
+		VISIT(c, expr, s->v.If.test);
+		ADDOP_JREL(c, JUMP_IF_FALSE, next);
+		ADDOP(c, POP_TOP);
+		VISIT_SEQ(c, stmt, s->v.If.body);
+		ADDOP_JREL(c, JUMP_FORWARD, end);
+		compiler_use_next_block(c, next);
+		ADDOP(c, POP_TOP);
+		if (s->v.If.orelse)
+	    		VISIT_SEQ(c, stmt, s->v.If.orelse);
+	}
+	compiler_use_next_block(c, end);
+	return 1;
+}
+
+static int
+compiler_for(struct compiler *c, stmt_ty s)
+{
+	basicblock *start, *cleanup, *end;
+
+	start = compiler_new_block(c);
+	cleanup = compiler_new_block(c);
+	end = compiler_new_block(c);
+	if (start == NULL || end == NULL || cleanup == NULL)
+		return 0;
+	ADDOP_JREL(c, SETUP_LOOP, end);
+	if (!compiler_push_fblock(c, LOOP, start))
+		return 0;
+	VISIT(c, expr, s->v.For.iter);
+	ADDOP(c, GET_ITER);
+	compiler_use_next_block(c, start);
+	/* XXX(nnorwitz): is there a better way to handle this?
+	   for loops are special, we want to be able to trace them
+	   each time around, so we need to set an extra line number. */
+	c->u->u_lineno_set = false;
+	ADDOP_JREL(c, FOR_ITER, cleanup);
+	VISIT(c, expr, s->v.For.target);
+	VISIT_SEQ(c, stmt, s->v.For.body);
+	ADDOP_JABS(c, JUMP_ABSOLUTE, start);
+	compiler_use_next_block(c, cleanup);
+	ADDOP(c, POP_BLOCK);
+	compiler_pop_fblock(c, LOOP, start);
+	VISIT_SEQ(c, stmt, s->v.For.orelse);
+	compiler_use_next_block(c, end);
+	return 1;
+}
+
+static int
+compiler_while(struct compiler *c, stmt_ty s)
+{
+	basicblock *loop, *orelse, *end, *anchor = NULL;
+	int constant = expr_constant(s->v.While.test);
+
+	if (constant == 0)
+		return 1;
+	loop = compiler_new_block(c);
+	end = compiler_new_block(c);
+	if (constant == -1) {
+		anchor = compiler_new_block(c);
+		if (anchor == NULL)
+			return 0;
+	}
+	if (loop == NULL || end == NULL)
+		return 0;
+	if (s->v.While.orelse) {
+		orelse = compiler_new_block(c);
+		if (orelse == NULL)
+			return 0;
+	}
+	else
+		orelse = NULL;
+
+	ADDOP_JREL(c, SETUP_LOOP, end);
+	compiler_use_next_block(c, loop);
+	if (!compiler_push_fblock(c, LOOP, loop))
+		return 0;
+	if (constant == -1) {
+		VISIT(c, expr, s->v.While.test);
+		ADDOP_JREL(c, JUMP_IF_FALSE, anchor);
+		ADDOP(c, POP_TOP);
+	}
+	VISIT_SEQ(c, stmt, s->v.While.body);
+	ADDOP_JABS(c, JUMP_ABSOLUTE, loop);
+
+	/* XXX should the two POP instructions be in a separate block
+	   if there is no else clause ?
+	*/
+
+	if (constant == -1) {
+		compiler_use_next_block(c, anchor);
+		ADDOP(c, POP_TOP);
+		ADDOP(c, POP_BLOCK);
+	}
+	compiler_pop_fblock(c, LOOP, loop);
+	if (orelse != NULL) /* what if orelse is just pass? */
+		VISIT_SEQ(c, stmt, s->v.While.orelse);
+	compiler_use_next_block(c, end);
+
+	return 1;
+}
+
+static int
+compiler_continue(struct compiler *c)
+{
+	static const char LOOP_ERROR_MSG[] = "'continue' not properly in loop";
+	static const char IN_FINALLY_ERROR_MSG[] = 
+			"'continue' not supported inside 'finally' clause";
+	int i;
+
+	if (!c->u->u_nfblocks)
+		return compiler_error(c, LOOP_ERROR_MSG);
+	i = c->u->u_nfblocks - 1;
+	switch (c->u->u_fblock[i].fb_type) {
+	case LOOP:
+		ADDOP_JABS(c, JUMP_ABSOLUTE, c->u->u_fblock[i].fb_block);
+		break;
+	case EXCEPT:
+	case FINALLY_TRY:
+		while (--i >= 0 && c->u->u_fblock[i].fb_type != LOOP) {
+			/* Prevent try: ... finally:
+			      try: continue ...  or
+			      try: ... except: continue */
+			if (c->u->u_fblock[i].fb_type == FINALLY_END)
+				return compiler_error(c, IN_FINALLY_ERROR_MSG);
+		}
+		if (i == -1)
+			return compiler_error(c, LOOP_ERROR_MSG);
+		ADDOP_JABS(c, CONTINUE_LOOP, c->u->u_fblock[i].fb_block);
+		break;
+	case FINALLY_END:
+		return compiler_error(c, IN_FINALLY_ERROR_MSG);
+	}
+
+	return 1;
+}
+
+/* Code generated for "try: <body> finally: <finalbody>" is as follows:
+   
+		SETUP_FINALLY	L
+		<code for body>
+		POP_BLOCK
+		LOAD_CONST	<None>
+	L:	<code for finalbody>
+		END_FINALLY
+   
+   The special instructions use the block stack.  Each block
+   stack entry contains the instruction that created it (here
+   SETUP_FINALLY), the level of the value stack at the time the
+   block stack entry was created, and a label (here L).
+   
+   SETUP_FINALLY:
+	Pushes the current value stack level and the label
+	onto the block stack.
+   POP_BLOCK:
+	Pops en entry from the block stack, and pops the value
+	stack until its level is the same as indicated on the
+	block stack.  (The label is ignored.)
+   END_FINALLY:
+	Pops a variable number of entries from the *value* stack
+	and re-raises the exception they specify.  The number of
+	entries popped depends on the (pseudo) exception type.
+   
+   The block stack is unwound when an exception is raised:
+   when a SETUP_FINALLY entry is found, the exception is pushed
+   onto the value stack (and the exception condition is cleared),
+   and the interpreter jumps to the label gotten from the block
+   stack.
+*/
+
+static int
+compiler_try_finally(struct compiler *c, stmt_ty s)
+{
+	basicblock *body, *end;
+	body = compiler_new_block(c);
+	end = compiler_new_block(c);
+	if (body == NULL || end == NULL)
+		return 0;
+
+	ADDOP_JREL(c, SETUP_FINALLY, end);
+	compiler_use_next_block(c, body);
+	if (!compiler_push_fblock(c, FINALLY_TRY, body))
+		return 0;
+	VISIT_SEQ(c, stmt, s->v.TryFinally.body);
+	ADDOP(c, POP_BLOCK);
+	compiler_pop_fblock(c, FINALLY_TRY, body);
+
+	ADDOP_O(c, LOAD_CONST, Py_None, consts);
+	compiler_use_next_block(c, end);
+	if (!compiler_push_fblock(c, FINALLY_END, end))
+		return 0;
+	VISIT_SEQ(c, stmt, s->v.TryFinally.finalbody);
+	ADDOP(c, END_FINALLY);
+	compiler_pop_fblock(c, FINALLY_END, end);
+
+	return 1;
+}
+
+/*
+   Code generated for "try: S except E1, V1: S1 except E2, V2: S2 ...":
+   (The contents of the value stack is shown in [], with the top
+   at the right; 'tb' is trace-back info, 'val' the exception's
+   associated value, and 'exc' the exception.)
+   
+   Value stack		Label	Instruction	Argument
+   []				SETUP_EXCEPT	L1
+   []				<code for S>
+   []				POP_BLOCK
+   []				JUMP_FORWARD	L0
+   
+   [tb, val, exc]	L1:	DUP				)
+   [tb, val, exc, exc]		<evaluate E1>			)
+   [tb, val, exc, exc, E1]	COMPARE_OP	EXC_MATCH	) only if E1
+   [tb, val, exc, 1-or-0]	JUMP_IF_FALSE	L2		)
+   [tb, val, exc, 1]		POP				)
+   [tb, val, exc]		POP
+   [tb, val]			<assign to V1>	(or POP if no V1)
+   [tb]				POP
+   []				<code for S1>
+				JUMP_FORWARD	L0
+   
+   [tb, val, exc, 0]	L2:	POP
+   [tb, val, exc]		DUP
+   .............................etc.......................
+
+   [tb, val, exc, 0]	Ln+1:	POP
+   [tb, val, exc]		END_FINALLY	# re-raise exception
+   
+   []			L0:	<next statement>
+   
+   Of course, parts are not generated if Vi or Ei is not present.
+*/
+static int
+compiler_try_except(struct compiler *c, stmt_ty s)
+{
+	basicblock *body, *orelse, *except, *end;
+	int i, n;
+
+	body = compiler_new_block(c);
+	except = compiler_new_block(c);
+	orelse = compiler_new_block(c);
+	end = compiler_new_block(c);
+	if (body == NULL || except == NULL || orelse == NULL || end == NULL)
+		return 0;
+	ADDOP_JREL(c, SETUP_EXCEPT, except);
+	compiler_use_next_block(c, body);
+	if (!compiler_push_fblock(c, EXCEPT, body))
+		return 0;
+	VISIT_SEQ(c, stmt, s->v.TryExcept.body);
+	ADDOP(c, POP_BLOCK);
+	compiler_pop_fblock(c, EXCEPT, body);
+	ADDOP_JREL(c, JUMP_FORWARD, orelse);
+	n = asdl_seq_LEN(s->v.TryExcept.handlers);
+	compiler_use_next_block(c, except);
+	for (i = 0; i < n; i++) {
+		excepthandler_ty handler = (excepthandler_ty)asdl_seq_GET(
+						s->v.TryExcept.handlers, i);
+		if (!handler->type && i < n-1)
+		    return compiler_error(c, "default 'except:' must be last");
+        c->u->u_lineno_set = false;
+        c->u->u_lineno = handler->lineno;
+		except = compiler_new_block(c);
+		if (except == NULL)
+			return 0;
+		if (handler->type) {
+			ADDOP(c, DUP_TOP);
+			VISIT(c, expr, handler->type);
+			ADDOP_I(c, COMPARE_OP, PyCmp_EXC_MATCH);
+			ADDOP_JREL(c, JUMP_IF_FALSE, except);
+			ADDOP(c, POP_TOP);
+		}
+		ADDOP(c, POP_TOP);
+		if (handler->name) {
+			VISIT(c, expr, handler->name);
+		}
+		else {
+			ADDOP(c, POP_TOP);
+		}
+		ADDOP(c, POP_TOP);
+		VISIT_SEQ(c, stmt, handler->body);
+		ADDOP_JREL(c, JUMP_FORWARD, end);
+		compiler_use_next_block(c, except);
+		if (handler->type)
+			ADDOP(c, POP_TOP);
+	}
+	ADDOP(c, END_FINALLY);
+	compiler_use_next_block(c, orelse);
+	VISIT_SEQ(c, stmt, s->v.TryExcept.orelse);
+	compiler_use_next_block(c, end);
+	return 1;
+}
+
+static int
+compiler_import_as(struct compiler *c, identifier name, identifier asname)
+{
+	/* The IMPORT_NAME opcode was already generated.  This function
+	   merely needs to bind the result to a name.
+
+	   If there is a dot in name, we need to split it and emit a 
+	   LOAD_ATTR for each name.
+	*/
+	const char *src = PyString_AS_STRING(name);
+	const char *dot = strchr(src, '.');
+	if (dot) {
+		/* Consume the base module name to get the first attribute */
+		src = dot + 1;
+		while (dot) {
+			/* NB src is only defined when dot != NULL */
+			PyObject *attr;
+			dot = strchr(src, '.');
+			attr = PyString_FromStringAndSize(src, 
+					    dot ? dot - src : strlen(src));
+			if (!attr)
+				return -1;
+			ADDOP_O(c, LOAD_ATTR, attr, names);
+			Py_DECREF(attr);
+			src = dot + 1;
+		}
+	}
+	return compiler_nameop(c, asname, Store);
+}
+
+static int
+compiler_import(struct compiler *c, stmt_ty s)
+{
+	/* The Import node stores a module name like a.b.c as a single
+	   string.  This is convenient for all cases except
+	     import a.b.c as d
+	   where we need to parse that string to extract the individual
+	   module names.  
+	   XXX Perhaps change the representation to make this case simpler?
+	 */
+	int i, n = asdl_seq_LEN(s->v.Import.names);
+
+	for (i = 0; i < n; i++) {
+		alias_ty alias = (alias_ty)asdl_seq_GET(s->v.Import.names, i);
+		int r;
+		PyObject *level;
+
+		if (c->c_flags && (c->c_flags->cf_flags & CO_FUTURE_ABSOLUTE_IMPORT))
+			level = PyInt_FromLong(0);
+		else
+			level = PyInt_FromLong(-1);
+
+		if (level == NULL)
+			return 0;
+
+		ADDOP_O(c, LOAD_CONST, level, consts);
+		Py_DECREF(level);
+		ADDOP_O(c, LOAD_CONST, Py_None, consts);
+		ADDOP_NAME(c, IMPORT_NAME, alias->name, names);
+
+		if (alias->asname) {
+			r = compiler_import_as(c, alias->name, alias->asname);
+			if (!r)
+			    return r;
+		}
+		else {
+			identifier tmp = alias->name;
+			const char *base = PyString_AS_STRING(alias->name);
+			char *dot = strchr(base, '.');
+			if (dot)
+				tmp = PyString_FromStringAndSize(base, 
+								 dot - base);
+			r = compiler_nameop(c, tmp, Store);
+			if (dot) {
+				Py_DECREF(tmp);
+			}
+			if (!r)
+				return r;
+		}
+	}
+	return 1;
+}
+
+static int
+compiler_from_import(struct compiler *c, stmt_ty s)
+{
+	int i, n = asdl_seq_LEN(s->v.ImportFrom.names);
+
+	PyObject *names = PyTuple_New(n);
+	PyObject *level;
+	
+	if (!names)
+		return 0;
+
+	if (s->v.ImportFrom.level == 0 && c->c_flags &&
+	    !(c->c_flags->cf_flags & CO_FUTURE_ABSOLUTE_IMPORT))
+		level = PyInt_FromLong(-1);
+	else
+		level = PyInt_FromLong(s->v.ImportFrom.level);
+
+	if (!level) {
+		Py_DECREF(names);
+		return 0;
+	}
+
+	/* build up the names */
+	for (i = 0; i < n; i++) {
+		alias_ty alias = (alias_ty)asdl_seq_GET(s->v.ImportFrom.names, i);
+		Py_INCREF(alias->name);
+		PyTuple_SET_ITEM(names, i, alias->name);
+	}
+
+	if (s->lineno > c->c_future->ff_lineno) {
+		if (!strcmp(PyString_AS_STRING(s->v.ImportFrom.module),
+			    "__future__")) {
+			Py_DECREF(level);
+			Py_DECREF(names);
+			return compiler_error(c, 
+				      "from __future__ imports must occur "
+				      "at the beginning of the file");
+
+		}
+	}
+
+	ADDOP_O(c, LOAD_CONST, level, consts);
+	Py_DECREF(level);
+	ADDOP_O(c, LOAD_CONST, names, consts);
+	Py_DECREF(names);
+	ADDOP_NAME(c, IMPORT_NAME, s->v.ImportFrom.module, names);
+	for (i = 0; i < n; i++) {
+		alias_ty alias = (alias_ty)asdl_seq_GET(s->v.ImportFrom.names, i);
+		identifier store_name;
+
+		if (i == 0 && *PyString_AS_STRING(alias->name) == '*') {
+			assert(n == 1);
+			ADDOP(c, IMPORT_STAR);
+			return 1;
+		}
+		    
+		ADDOP_NAME(c, IMPORT_FROM, alias->name, names);
+		store_name = alias->name;
+		if (alias->asname)
+			store_name = alias->asname;
+
+		if (!compiler_nameop(c, store_name, Store)) {
+			Py_DECREF(names);
+			return 0;
+		}
+	}
+	/* remove imported module */
+	ADDOP(c, POP_TOP);
+	return 1;
+}
+
+static int
+compiler_assert(struct compiler *c, stmt_ty s)
+{
+	static PyObject *assertion_error = NULL;
+	basicblock *end;
+
+	if (Py_OptimizeFlag)
+		return 1;
+	if (assertion_error == NULL) {
+		assertion_error = PyString_FromString("AssertionError");
+		if (assertion_error == NULL)
+			return 0;
+	}
+	VISIT(c, expr, s->v.Assert.test);
+	end = compiler_new_block(c);
+	if (end == NULL)
+		return 0;
+	ADDOP_JREL(c, JUMP_IF_TRUE, end);
+	ADDOP(c, POP_TOP);
+	ADDOP_O(c, LOAD_GLOBAL, assertion_error, names);
+	if (s->v.Assert.msg) {
+		VISIT(c, expr, s->v.Assert.msg);
+		ADDOP_I(c, RAISE_VARARGS, 2);
+	}
+	else {
+		ADDOP_I(c, RAISE_VARARGS, 1);
+	}
+	compiler_use_next_block(c, end);
+	ADDOP(c, POP_TOP);
+	return 1;
+}
+
+static int
+compiler_visit_stmt(struct compiler *c, stmt_ty s)
+{
+	int i, n;
+
+    /* Always assign a lineno to the next instruction for a stmt. */
+	c->u->u_lineno = s->lineno;
+	c->u->u_lineno_set = false;
+
+	switch (s->kind) {
+	case FunctionDef_kind:
+		return compiler_function(c, s);
+	case ClassDef_kind:
+		return compiler_class(c, s);
+	case Return_kind:
+		if (c->u->u_ste->ste_type != FunctionBlock)
+			return compiler_error(c, "'return' outside function");
+		if (s->v.Return.value) {
+			VISIT(c, expr, s->v.Return.value);
+		}
+		else
+			ADDOP_O(c, LOAD_CONST, Py_None, consts);
+		ADDOP(c, RETURN_VALUE);
+		break;
+	case Delete_kind:
+		VISIT_SEQ(c, expr, s->v.Delete.targets)
+		break;
+	case Assign_kind:
+		n = asdl_seq_LEN(s->v.Assign.targets);
+		VISIT(c, expr, s->v.Assign.value);
+		for (i = 0; i < n; i++) {
+			if (i < n - 1)
+				ADDOP(c, DUP_TOP);
+			VISIT(c, expr,
+			      (expr_ty)asdl_seq_GET(s->v.Assign.targets, i));
+		}
+		break;
+	case AugAssign_kind:
+		return compiler_augassign(c, s);
+	case Print_kind:
+		return compiler_print(c, s);
+	case For_kind:
+		return compiler_for(c, s);
+	case While_kind:
+		return compiler_while(c, s);
+	case If_kind:
+		return compiler_if(c, s);
+	case Raise_kind:
+		n = 0;
+		if (s->v.Raise.type) {
+			VISIT(c, expr, s->v.Raise.type);
+			n++;
+			if (s->v.Raise.inst) {
+				VISIT(c, expr, s->v.Raise.inst);
+				n++;
+				if (s->v.Raise.tback) {
+					VISIT(c, expr, s->v.Raise.tback);
+					n++;
+				}
+			}
+		}
+		ADDOP_I(c, RAISE_VARARGS, n);
+		break;
+	case TryExcept_kind:
+		return compiler_try_except(c, s);
+	case TryFinally_kind:
+		return compiler_try_finally(c, s);
+	case Assert_kind:
+		return compiler_assert(c, s);
+	case Import_kind:
+		return compiler_import(c, s);
+	case ImportFrom_kind:
+		return compiler_from_import(c, s);
+	case Exec_kind:
+		VISIT(c, expr, s->v.Exec.body);
+		if (s->v.Exec.globals) {
+			VISIT(c, expr, s->v.Exec.globals);
+			if (s->v.Exec.locals) {
+				VISIT(c, expr, s->v.Exec.locals);
+			} else {
+				ADDOP(c, DUP_TOP);
+			}
+		} else {
+			ADDOP_O(c, LOAD_CONST, Py_None, consts);
+			ADDOP(c, DUP_TOP);
+		}
+		ADDOP(c, EXEC_STMT);
+		break;
+	case Global_kind:
+		break;
+	case Expr_kind:
+		if (c->c_interactive && c->c_nestlevel <= 1) {
+			VISIT(c, expr, s->v.Expr.value);
+			ADDOP(c, PRINT_EXPR);
+		}
+		else if (s->v.Expr.value->kind != Str_kind &&
+			 s->v.Expr.value->kind != Num_kind) {
+			VISIT(c, expr, s->v.Expr.value);
+			ADDOP(c, POP_TOP);
+		}
+		break;
+	case Pass_kind:
+		break;
+	case Break_kind:
+                if (!compiler_in_loop(c))
+			return compiler_error(c, "'break' outside loop");
+		ADDOP(c, BREAK_LOOP);
+		break;
+	case Continue_kind:
+		return compiler_continue(c);
+	case With_kind:
+		return compiler_with(c, s);
+	}
+	return 1;
+}
+
+static int
+unaryop(unaryop_ty op)
+{
+	switch (op) {
+	case Invert:
+		return UNARY_INVERT;
+	case Not:
+		return UNARY_NOT;
+	case UAdd:
+		return UNARY_POSITIVE;
+	case USub:
+		return UNARY_NEGATIVE;
+	}
+	return 0;
+}
+
+static int
+binop(struct compiler *c, operator_ty op)
+{
+	switch (op) {
+	case Add:
+		return BINARY_ADD;
+	case Sub:
+		return BINARY_SUBTRACT;
+	case Mult:
+		return BINARY_MULTIPLY;
+	case Div:
+		if (c->c_flags && c->c_flags->cf_flags & CO_FUTURE_DIVISION)
+			return BINARY_TRUE_DIVIDE;
+		else
+			return BINARY_DIVIDE;
+	case Mod:
+		return BINARY_MODULO;
+	case Pow:
+		return BINARY_POWER;
+	case LShift:
+		return BINARY_LSHIFT;
+	case RShift:
+		return BINARY_RSHIFT;
+	case BitOr:
+		return BINARY_OR;
+	case BitXor:
+		return BINARY_XOR;
+	case BitAnd:
+		return BINARY_AND;
+	case FloorDiv:
+		return BINARY_FLOOR_DIVIDE;
+	}
+	return 0;
+}
+
+static int
+cmpop(cmpop_ty op)
+{
+	switch (op) {
+	case Eq:
+		return PyCmp_EQ;
+	case NotEq:
+		return PyCmp_NE;
+	case Lt:
+		return PyCmp_LT;
+	case LtE:
+		return PyCmp_LE;
+	case Gt:
+		return PyCmp_GT;
+	case GtE:
+		return PyCmp_GE;
+	case Is:
+		return PyCmp_IS;
+	case IsNot:
+		return PyCmp_IS_NOT;
+	case In:
+		return PyCmp_IN;
+	case NotIn:
+		return PyCmp_NOT_IN;
+	}
+	return PyCmp_BAD;
+}
+
+static int
+inplace_binop(struct compiler *c, operator_ty op)
+{
+	switch (op) {
+	case Add:
+		return INPLACE_ADD;
+	case Sub:
+		return INPLACE_SUBTRACT;
+	case Mult:
+		return INPLACE_MULTIPLY;
+	case Div:
+		if (c->c_flags && c->c_flags->cf_flags & CO_FUTURE_DIVISION)
+			return INPLACE_TRUE_DIVIDE;
+		else
+			return INPLACE_DIVIDE;
+	case Mod:
+		return INPLACE_MODULO;
+	case Pow:
+		return INPLACE_POWER;
+	case LShift:
+		return INPLACE_LSHIFT;
+	case RShift:
+		return INPLACE_RSHIFT;
+	case BitOr:
+		return INPLACE_OR;
+	case BitXor:
+		return INPLACE_XOR;
+	case BitAnd:
+		return INPLACE_AND;
+	case FloorDiv:
+		return INPLACE_FLOOR_DIVIDE;
+	}
+	PyErr_Format(PyExc_SystemError,
+		     "inplace binary op %d should not be possible", op);
+	return 0;
+}
+
+static int
+compiler_nameop(struct compiler *c, identifier name, expr_context_ty ctx)
+{
+	int op, scope, arg;
+	enum { OP_FAST, OP_GLOBAL, OP_DEREF, OP_NAME } optype;
+
+	PyObject *dict = c->u->u_names;
+	PyObject *mangled;
+	/* XXX AugStore isn't used anywhere! */
+
+	/* First check for assignment to __debug__. Param? */
+	if ((ctx == Store || ctx == AugStore || ctx == Del)
+	    && !strcmp(PyString_AS_STRING(name), "__debug__")) {
+		return compiler_error(c, "can not assign to __debug__");
+	}
+
+	mangled = _Py_Mangle(c->u->u_private, name);
+	if (!mangled)
+		return 0;
+
+	op = 0;
+	optype = OP_NAME;
+	scope = PyST_GetScope(c->u->u_ste, mangled);
+	switch (scope) {
+	case FREE:
+		dict = c->u->u_freevars;
+		optype = OP_DEREF;
+		break;
+	case CELL:
+		dict = c->u->u_cellvars;
+		optype = OP_DEREF;
+		break;
+	case LOCAL:
+		if (c->u->u_ste->ste_type == FunctionBlock)
+			optype = OP_FAST;
+		break;
+	case GLOBAL_IMPLICIT:
+		if (c->u->u_ste->ste_type == FunctionBlock &&
+			!c->u->u_ste->ste_unoptimized)
+			optype = OP_GLOBAL;
+		break;
+	case GLOBAL_EXPLICIT:
+		optype = OP_GLOBAL;
+		break;
+	default:
+		/* scope can be 0 */
+		break;
+	}
+
+	/* XXX Leave assert here, but handle __doc__ and the like better */
+	assert(scope || PyString_AS_STRING(name)[0] == '_');
+
+	switch (optype) {
+	case OP_DEREF:
+		switch (ctx) {
+		case Load: op = LOAD_DEREF; break;
+		case Store: op = STORE_DEREF; break;
+		case AugLoad:
+		case AugStore:
+			break;
+		case Del:
+			PyErr_Format(PyExc_SyntaxError,
+				     "can not delete variable '%s' referenced "
+				     "in nested scope",
+				     PyString_AS_STRING(name));
+			Py_DECREF(mangled);
+			return 0;
+		case Param:
+		default:
+			PyErr_SetString(PyExc_SystemError,
+					"param invalid for deref variable");
+			return 0;
+		}
+		break;
+	case OP_FAST:
+		switch (ctx) {
+		case Load: op = LOAD_FAST; break;
+		case Store: op = STORE_FAST; break;
+		case Del: op = DELETE_FAST; break;
+		case AugLoad:
+		case AugStore:
+			break;
+		case Param:
+		default:
+			PyErr_SetString(PyExc_SystemError,
+					"param invalid for local variable");
+			return 0;
+		}
+		ADDOP_O(c, op, mangled, varnames);
+		Py_DECREF(mangled);
+		return 1;
+	case OP_GLOBAL:
+		switch (ctx) {
+		case Load: op = LOAD_GLOBAL; break;
+		case Store: op = STORE_GLOBAL; break;
+		case Del: op = DELETE_GLOBAL; break;
+		case AugLoad:
+		case AugStore:
+			break;
+		case Param:
+		default:
+			PyErr_SetString(PyExc_SystemError,
+					"param invalid for global variable");
+			return 0;
+		}
+		break;
+	case OP_NAME:
+		switch (ctx) {
+		case Load: op = LOAD_NAME; break;
+		case Store: op = STORE_NAME; break;
+		case Del: op = DELETE_NAME; break;
+		case AugLoad:
+		case AugStore:
+			break;
+		case Param:
+		default:
+			PyErr_SetString(PyExc_SystemError,
+					"param invalid for name variable");
+			return 0;
+		}
+		break;
+	}
+
+	assert(op);
+	arg = compiler_add_o(c, dict, mangled);
+	Py_DECREF(mangled);
+	if (arg < 0)
+		return 0;
+	return compiler_addop_i(c, op, arg);
+}
+
+static int
+compiler_boolop(struct compiler *c, expr_ty e)
+{
+	basicblock *end;
+	int jumpi, i, n;
+	asdl_seq *s;
+
+	assert(e->kind == BoolOp_kind);
+	if (e->v.BoolOp.op == And)
+		jumpi = JUMP_IF_FALSE;
+	else
+		jumpi = JUMP_IF_TRUE;
+	end = compiler_new_block(c);
+	if (end == NULL)
+		return 0;
+	s = e->v.BoolOp.values;
+	n = asdl_seq_LEN(s) - 1;
+	assert(n >= 0);
+	for (i = 0; i < n; ++i) {
+		VISIT(c, expr, (expr_ty)asdl_seq_GET(s, i));
+		ADDOP_JREL(c, jumpi, end);
+		ADDOP(c, POP_TOP)
+	}
+	VISIT(c, expr, (expr_ty)asdl_seq_GET(s, n));
+	compiler_use_next_block(c, end);
+	return 1;
+}
+
+static int
+compiler_list(struct compiler *c, expr_ty e)
+{
+	int n = asdl_seq_LEN(e->v.List.elts);
+	if (e->v.List.ctx == Store) {
+		ADDOP_I(c, UNPACK_SEQUENCE, n);
+	}
+	VISIT_SEQ(c, expr, e->v.List.elts);
+	if (e->v.List.ctx == Load) {
+		ADDOP_I(c, BUILD_LIST, n);
+	}
+	return 1;
+}
+
+static int
+compiler_tuple(struct compiler *c, expr_ty e)
+{
+	int n = asdl_seq_LEN(e->v.Tuple.elts);
+	if (e->v.Tuple.ctx == Store) {
+		ADDOP_I(c, UNPACK_SEQUENCE, n);
+	}
+	VISIT_SEQ(c, expr, e->v.Tuple.elts);
+	if (e->v.Tuple.ctx == Load) {
+		ADDOP_I(c, BUILD_TUPLE, n);
+	}
+	return 1;
+}
+
+static int
+compiler_compare(struct compiler *c, expr_ty e)
+{
+	int i, n;
+	basicblock *cleanup = NULL;
+
+	/* XXX the logic can be cleaned up for 1 or multiple comparisons */
+	VISIT(c, expr, e->v.Compare.left);
+	n = asdl_seq_LEN(e->v.Compare.ops);
+	assert(n > 0);
+	if (n > 1) {
+		cleanup = compiler_new_block(c);
+		if (cleanup == NULL)
+		    return 0;
+		VISIT(c, expr, 
+                        (expr_ty)asdl_seq_GET(e->v.Compare.comparators, 0));
+	}
+	for (i = 1; i < n; i++) {
+		ADDOP(c, DUP_TOP);
+		ADDOP(c, ROT_THREE);
+		ADDOP_I(c, COMPARE_OP,
+			cmpop((cmpop_ty)(asdl_seq_GET(
+                                                  e->v.Compare.ops, i - 1))));
+		ADDOP_JREL(c, JUMP_IF_FALSE, cleanup);
+		NEXT_BLOCK(c);
+		ADDOP(c, POP_TOP);
+		if (i < (n - 1))
+		    VISIT(c, expr, 
+                            (expr_ty)asdl_seq_GET(e->v.Compare.comparators, i));
+	}
+	VISIT(c, expr, (expr_ty)asdl_seq_GET(e->v.Compare.comparators, n - 1));
+	ADDOP_I(c, COMPARE_OP,
+	       cmpop((cmpop_ty)(asdl_seq_GET(e->v.Compare.ops, n - 1))));
+	if (n > 1) {
+		basicblock *end = compiler_new_block(c);
+		if (end == NULL)
+		    return 0;
+		ADDOP_JREL(c, JUMP_FORWARD, end);
+		compiler_use_next_block(c, cleanup);
+		ADDOP(c, ROT_TWO);
+		ADDOP(c, POP_TOP);
+		compiler_use_next_block(c, end);
+	}
+	return 1;
+}
+#undef CMPCAST
+
+static int
+compiler_call(struct compiler *c, expr_ty e)
+{
+	int n, code = 0;
+
+	VISIT(c, expr, e->v.Call.func);
+	n = asdl_seq_LEN(e->v.Call.args);
+	VISIT_SEQ(c, expr, e->v.Call.args);
+	if (e->v.Call.keywords) {
+		VISIT_SEQ(c, keyword, e->v.Call.keywords);
+		n |= asdl_seq_LEN(e->v.Call.keywords) << 8;
+	}
+	if (e->v.Call.starargs) {
+		VISIT(c, expr, e->v.Call.starargs);
+		code |= 1;
+	}
+	if (e->v.Call.kwargs) {
+		VISIT(c, expr, e->v.Call.kwargs);
+		code |= 2;
+	}
+	switch (code) {
+	case 0:
+		ADDOP_I(c, CALL_FUNCTION, n);
+		break;
+	case 1:
+		ADDOP_I(c, CALL_FUNCTION_VAR, n);
+		break;
+	case 2:
+		ADDOP_I(c, CALL_FUNCTION_KW, n);
+		break;
+	case 3:
+		ADDOP_I(c, CALL_FUNCTION_VAR_KW, n);
+		break;
+	}
+	return 1;
+}
+
+static int
+compiler_listcomp_generator(struct compiler *c, PyObject *tmpname,
+			    asdl_seq *generators, int gen_index, 
+			    expr_ty elt)
+{
+	/* generate code for the iterator, then each of the ifs,
+	   and then write to the element */
+
+	comprehension_ty l;
+	basicblock *start, *anchor, *skip, *if_cleanup;
+	int i, n;
+
+	start = compiler_new_block(c);
+	skip = compiler_new_block(c);
+	if_cleanup = compiler_new_block(c);
+	anchor = compiler_new_block(c);
+
+	if (start == NULL || skip == NULL || if_cleanup == NULL ||
+		anchor == NULL)
+	    return 0;
+
+	l = (comprehension_ty)asdl_seq_GET(generators, gen_index);
+	VISIT(c, expr, l->iter);
+	ADDOP(c, GET_ITER);
+	compiler_use_next_block(c, start);
+	ADDOP_JREL(c, FOR_ITER, anchor);
+	NEXT_BLOCK(c);
+	VISIT(c, expr, l->target);
+
+	/* XXX this needs to be cleaned up...a lot! */
+	n = asdl_seq_LEN(l->ifs);
+	for (i = 0; i < n; i++) {
+		expr_ty e = (expr_ty)asdl_seq_GET(l->ifs, i);
+		VISIT(c, expr, e);
+		ADDOP_JREL(c, JUMP_IF_FALSE, if_cleanup);
+		NEXT_BLOCK(c);
+		ADDOP(c, POP_TOP);
+	} 
+
+	if (++gen_index < asdl_seq_LEN(generators))
+	    if (!compiler_listcomp_generator(c, tmpname, 
+					     generators, gen_index, elt))
+		return 0;
+
+	/* only append after the last for generator */
+	if (gen_index >= asdl_seq_LEN(generators)) {
+	    if (!compiler_nameop(c, tmpname, Load))
+		return 0;
+	    VISIT(c, expr, elt);
+	    ADDOP(c, LIST_APPEND);
+
+	    compiler_use_next_block(c, skip);
+	}
+	for (i = 0; i < n; i++) {
+		ADDOP_I(c, JUMP_FORWARD, 1);
+		if (i == 0)
+		    compiler_use_next_block(c, if_cleanup);
+		ADDOP(c, POP_TOP);
+	} 
+	ADDOP_JABS(c, JUMP_ABSOLUTE, start);
+	compiler_use_next_block(c, anchor);
+	/* delete the append method added to locals */
+	if (gen_index == 1)
+	    if (!compiler_nameop(c, tmpname, Del))
+		return 0;
+	
+	return 1;
+}
+
+static int
+compiler_listcomp(struct compiler *c, expr_ty e)
+{
+	identifier tmp;
+	int rc = 0;
+	static identifier append;
+	asdl_seq *generators = e->v.ListComp.generators;
+
+	assert(e->kind == ListComp_kind);
+	if (!append) {
+		append = PyString_InternFromString("append");
+		if (!append)
+			return 0;
+	}
+	tmp = compiler_new_tmpname(c);
+	if (!tmp)
+		return 0;
+	ADDOP_I(c, BUILD_LIST, 0);
+	ADDOP(c, DUP_TOP);
+	if (compiler_nameop(c, tmp, Store))
+	    rc = compiler_listcomp_generator(c, tmp, generators, 0, 
+					     e->v.ListComp.elt);
+	Py_DECREF(tmp);
+	return rc;
+}
+
+static int
+compiler_genexp_generator(struct compiler *c,
+			  asdl_seq *generators, int gen_index, 
+			  expr_ty elt)
+{
+	/* generate code for the iterator, then each of the ifs,
+	   and then write to the element */
+
+	comprehension_ty ge;
+	basicblock *start, *anchor, *skip, *if_cleanup, *end;
+	int i, n;
+
+	start = compiler_new_block(c);
+	skip = compiler_new_block(c);
+	if_cleanup = compiler_new_block(c);
+	anchor = compiler_new_block(c);
+	end = compiler_new_block(c);
+
+	if (start == NULL || skip == NULL || if_cleanup == NULL ||
+	    anchor == NULL || end == NULL)
+		return 0;
+
+	ge = (comprehension_ty)asdl_seq_GET(generators, gen_index);
+	ADDOP_JREL(c, SETUP_LOOP, end);
+	if (!compiler_push_fblock(c, LOOP, start))
+		return 0;
+
+	if (gen_index == 0) {
+		/* Receive outermost iter as an implicit argument */
+		c->u->u_argcount = 1;
+		ADDOP_I(c, LOAD_FAST, 0);
+	}
+	else {
+		/* Sub-iter - calculate on the fly */
+		VISIT(c, expr, ge->iter);
+		ADDOP(c, GET_ITER);
+	}
+	compiler_use_next_block(c, start);
+	ADDOP_JREL(c, FOR_ITER, anchor);
+	NEXT_BLOCK(c);
+	VISIT(c, expr, ge->target);
+
+	/* XXX this needs to be cleaned up...a lot! */
+	n = asdl_seq_LEN(ge->ifs);
+	for (i = 0; i < n; i++) {
+		expr_ty e = (expr_ty)asdl_seq_GET(ge->ifs, i);
+		VISIT(c, expr, e);
+		ADDOP_JREL(c, JUMP_IF_FALSE, if_cleanup);
+		NEXT_BLOCK(c);
+		ADDOP(c, POP_TOP);
+	} 
+
+	if (++gen_index < asdl_seq_LEN(generators))
+		if (!compiler_genexp_generator(c, generators, gen_index, elt))
+			return 0;
+
+	/* only append after the last 'for' generator */
+	if (gen_index >= asdl_seq_LEN(generators)) {
+		VISIT(c, expr, elt);
+		ADDOP(c, YIELD_VALUE);
+		ADDOP(c, POP_TOP);
+
+		compiler_use_next_block(c, skip);
+	}
+	for (i = 0; i < n; i++) {
+		ADDOP_I(c, JUMP_FORWARD, 1);
+		if (i == 0)
+			compiler_use_next_block(c, if_cleanup);
+
+		ADDOP(c, POP_TOP);
+	} 
+	ADDOP_JABS(c, JUMP_ABSOLUTE, start);
+	compiler_use_next_block(c, anchor);
+	ADDOP(c, POP_BLOCK);
+	compiler_pop_fblock(c, LOOP, start);
+	compiler_use_next_block(c, end);
+
+	return 1;
+}
+
+static int
+compiler_genexp(struct compiler *c, expr_ty e)
+{
+	static identifier name;
+	PyCodeObject *co;
+	expr_ty outermost_iter = ((comprehension_ty)
+				 (asdl_seq_GET(e->v.GeneratorExp.generators,
+					       0)))->iter;
+
+	if (!name) {
+		name = PyString_FromString("<genexpr>");
+		if (!name)
+			return 0;
+	}
+
+	if (!compiler_enter_scope(c, name, (void *)e, e->lineno))
+		return 0;
+	compiler_genexp_generator(c, e->v.GeneratorExp.generators, 0,
+				  e->v.GeneratorExp.elt);
+	co = assemble(c, 1);
+	compiler_exit_scope(c);
+	if (co == NULL)
+		return 0;
+
+	compiler_make_closure(c, co, 0);
+	Py_DECREF(co);
+
+	VISIT(c, expr, outermost_iter);
+	ADDOP(c, GET_ITER);
+	ADDOP_I(c, CALL_FUNCTION, 1);
+
+	return 1;
+}
+
+static int
+compiler_visit_keyword(struct compiler *c, keyword_ty k)
+{
+	ADDOP_O(c, LOAD_CONST, k->arg, consts);
+	VISIT(c, expr, k->value);
+	return 1;
+}
+
+/* Test whether expression is constant.	 For constants, report
+   whether they are true or false.
+
+   Return values: 1 for true, 0 for false, -1 for non-constant.
+ */
+
+static int
+expr_constant(expr_ty e)
+{
+	switch (e->kind) {
+	case Num_kind:
+		return PyObject_IsTrue(e->v.Num.n);
+	case Str_kind:
+		return PyObject_IsTrue(e->v.Str.s);
+	case Name_kind:
+		/* __debug__ is not assignable, so we can optimize
+		 * it away in if and while statements */
+		if (strcmp(PyString_AS_STRING(e->v.Name.id),
+		           "__debug__") == 0)
+			   return ! Py_OptimizeFlag;
+		/* fall through */
+	default:
+		return -1;
+	}
+}
+
+/*
+   Implements the with statement from PEP 343.
+
+   The semantics outlined in that PEP are as follows:  
+
+   with EXPR as VAR:
+       BLOCK
+  
+   It is implemented roughly as:
+  
+   context = EXPR
+   exit = context.__exit__  # not calling it
+   value = context.__enter__()
+   try:
+       VAR = value  # if VAR present in the syntax
+       BLOCK
+   finally:
+       if an exception was raised:
+	   exc = copy of (exception, instance, traceback)
+       else:
+	   exc = (None, None, None)
+       exit(*exc)
+ */
+static int
+compiler_with(struct compiler *c, stmt_ty s)
+{
+    static identifier enter_attr, exit_attr;
+    basicblock *block, *finally;
+    identifier tmpexit, tmpvalue = NULL;
+
+    assert(s->kind == With_kind);
+
+    if (!enter_attr) {
+	enter_attr = PyString_InternFromString("__enter__");
+	if (!enter_attr)
+	    return 0;
+    }
+    if (!exit_attr) {
+	exit_attr = PyString_InternFromString("__exit__");
+	if (!exit_attr)
+	    return 0;
+    }
+
+    block = compiler_new_block(c);
+    finally = compiler_new_block(c);
+    if (!block || !finally)
+	return 0;
+
+    /* Create a temporary variable to hold context.__exit__ */
+    tmpexit = compiler_new_tmpname(c);
+    if (tmpexit == NULL)
+	return 0;
+    PyArena_AddPyObject(c->c_arena, tmpexit);
+
+    if (s->v.With.optional_vars) {
+	/* Create a temporary variable to hold context.__enter__().
+	   We need to do this rather than preserving it on the stack
+	   because SETUP_FINALLY remembers the stack level.
+	   We need to do the assignment *inside* the try/finally
+	   so that context.__exit__() is called when the assignment
+	   fails.  But we need to call context.__enter__() *before*
+	   the try/finally so that if it fails we won't call
+	   context.__exit__().
+	*/
+	tmpvalue = compiler_new_tmpname(c);
+	if (tmpvalue == NULL)
+	    return 0;
+	PyArena_AddPyObject(c->c_arena, tmpvalue);
+    }
+
+    /* Evaluate EXPR */
+    VISIT(c, expr, s->v.With.context_expr);
+
+    /* Squirrel away context.__exit__  */
+    ADDOP(c, DUP_TOP);
+    ADDOP_O(c, LOAD_ATTR, exit_attr, names);
+    if (!compiler_nameop(c, tmpexit, Store))
+	return 0;
+
+    /* Call context.__enter__() */
+    ADDOP_O(c, LOAD_ATTR, enter_attr, names);
+    ADDOP_I(c, CALL_FUNCTION, 0);
+
+    if (s->v.With.optional_vars) {
+	/* Store it in tmpvalue */
+	if (!compiler_nameop(c, tmpvalue, Store))
+	    return 0;
+    }
+    else {
+	/* Discard result from context.__enter__() */
+	ADDOP(c, POP_TOP);
+    }
+
+    /* Start the try block */
+    ADDOP_JREL(c, SETUP_FINALLY, finally);
+
+    compiler_use_next_block(c, block);
+    if (!compiler_push_fblock(c, FINALLY_TRY, block)) {
+	return 0;
+    }
+
+    if (s->v.With.optional_vars) {
+	/* Bind saved result of context.__enter__() to VAR */
+	if (!compiler_nameop(c, tmpvalue, Load) ||
+	    !compiler_nameop(c, tmpvalue, Del))
+	  return 0;
+	VISIT(c, expr, s->v.With.optional_vars);
+    }
+
+    /* BLOCK code */
+    VISIT_SEQ(c, stmt, s->v.With.body);
+
+    /* End of try block; start the finally block */
+    ADDOP(c, POP_BLOCK);
+    compiler_pop_fblock(c, FINALLY_TRY, block);
+
+    ADDOP_O(c, LOAD_CONST, Py_None, consts);
+    compiler_use_next_block(c, finally);
+    if (!compiler_push_fblock(c, FINALLY_END, finally))
+	return 0;
+
+    /* Finally block starts; push tmpexit and issue our magic opcode. */
+    if (!compiler_nameop(c, tmpexit, Load) ||
+	!compiler_nameop(c, tmpexit, Del))
+	return 0;
+    ADDOP(c, WITH_CLEANUP);
+
+    /* Finally block ends. */
+    ADDOP(c, END_FINALLY);
+    compiler_pop_fblock(c, FINALLY_END, finally);
+    return 1;
+}
+
+static int
+compiler_visit_expr(struct compiler *c, expr_ty e)
+{
+	int i, n;
+
+    /* If expr e has a different line number than the last expr/stmt,
+       set a new line number for the next instruction.
+       */
+	if (e->lineno > c->u->u_lineno) {
+		c->u->u_lineno = e->lineno;
+		c->u->u_lineno_set = false;
+	}
+	switch (e->kind) {
+	case BoolOp_kind:
+		return compiler_boolop(c, e);
+	case BinOp_kind:
+		VISIT(c, expr, e->v.BinOp.left);
+		VISIT(c, expr, e->v.BinOp.right);
+		ADDOP(c, binop(c, e->v.BinOp.op));
+		break;
+	case UnaryOp_kind:
+		VISIT(c, expr, e->v.UnaryOp.operand);
+		ADDOP(c, unaryop(e->v.UnaryOp.op));
+		break;
+	case Lambda_kind:
+		return compiler_lambda(c, e);
+	case IfExp_kind:
+		return compiler_ifexp(c, e);
+	case Dict_kind:
+		/* XXX get rid of arg? */
+		ADDOP_I(c, BUILD_MAP, 0);
+		n = asdl_seq_LEN(e->v.Dict.values);
+		/* We must arrange things just right for STORE_SUBSCR.
+		   It wants the stack to look like (value) (dict) (key) */
+		for (i = 0; i < n; i++) {
+			ADDOP(c, DUP_TOP);
+			VISIT(c, expr, 
+                                (expr_ty)asdl_seq_GET(e->v.Dict.values, i));
+			ADDOP(c, ROT_TWO);
+			VISIT(c, expr, 
+                                (expr_ty)asdl_seq_GET(e->v.Dict.keys, i));
+			ADDOP(c, STORE_SUBSCR);
+		}
+		break;
+	case ListComp_kind:
+		return compiler_listcomp(c, e);
+	case GeneratorExp_kind:
+		return compiler_genexp(c, e);
+	case Yield_kind:
+		if (c->u->u_ste->ste_type != FunctionBlock)
+			return compiler_error(c, "'yield' outside function");
+		/*
+		for (i = 0; i < c->u->u_nfblocks; i++) {
+			if (c->u->u_fblock[i].fb_type == FINALLY_TRY)
+				return compiler_error(
+					c, "'yield' not allowed in a 'try' "
+					"block with a 'finally' clause");
+		}
+		*/
+		if (e->v.Yield.value) {
+			VISIT(c, expr, e->v.Yield.value);
+		}
+		else {
+			ADDOP_O(c, LOAD_CONST, Py_None, consts);
+		}
+		ADDOP(c, YIELD_VALUE);
+		break;
+	case Compare_kind:
+		return compiler_compare(c, e);
+	case Call_kind:
+		return compiler_call(c, e);
+	case Repr_kind:
+		VISIT(c, expr, e->v.Repr.value);
+		ADDOP(c, UNARY_CONVERT);
+		break;
+	case Num_kind:
+		ADDOP_O(c, LOAD_CONST, e->v.Num.n, consts);
+		break;
+	case Str_kind:
+		ADDOP_O(c, LOAD_CONST, e->v.Str.s, consts);
+		break;
+	/* The following exprs can be assignment targets. */
+	case Attribute_kind:
+		if (e->v.Attribute.ctx != AugStore)
+			VISIT(c, expr, e->v.Attribute.value);
+		switch (e->v.Attribute.ctx) {
+		case AugLoad:
+			ADDOP(c, DUP_TOP);
+			/* Fall through to load */
+		case Load:
+			ADDOP_NAME(c, LOAD_ATTR, e->v.Attribute.attr, names);
+			break;
+		case AugStore:
+			ADDOP(c, ROT_TWO);
+			/* Fall through to save */
+		case Store:
+			ADDOP_NAME(c, STORE_ATTR, e->v.Attribute.attr, names);
+			break;
+		case Del:
+			ADDOP_NAME(c, DELETE_ATTR, e->v.Attribute.attr, names);
+			break;
+		case Param:
+		default:
+			PyErr_SetString(PyExc_SystemError,
+					"param invalid in attribute expression");
+			return 0;
+		}
+		break;
+	case Subscript_kind:
+		switch (e->v.Subscript.ctx) {
+		case AugLoad:
+			VISIT(c, expr, e->v.Subscript.value);
+			VISIT_SLICE(c, e->v.Subscript.slice, AugLoad);
+			break;
+		case Load:
+			VISIT(c, expr, e->v.Subscript.value);
+			VISIT_SLICE(c, e->v.Subscript.slice, Load);
+			break;
+		case AugStore:
+			VISIT_SLICE(c, e->v.Subscript.slice, AugStore);
+			break;
+		case Store:
+			VISIT(c, expr, e->v.Subscript.value);
+			VISIT_SLICE(c, e->v.Subscript.slice, Store);
+			break;
+		case Del:
+			VISIT(c, expr, e->v.Subscript.value);
+			VISIT_SLICE(c, e->v.Subscript.slice, Del);
+			break;
+		case Param:
+		default:
+			PyErr_SetString(PyExc_SystemError,
+				"param invalid in subscript expression");
+			return 0;
+		}
+		break;
+	case Name_kind:
+		return compiler_nameop(c, e->v.Name.id, e->v.Name.ctx);
+	/* child nodes of List and Tuple will have expr_context set */
+	case List_kind:
+		return compiler_list(c, e);
+	case Tuple_kind:
+		return compiler_tuple(c, e);
+	}
+	return 1;
+}
+
+static int
+compiler_augassign(struct compiler *c, stmt_ty s)
+{
+	expr_ty e = s->v.AugAssign.target;
+	expr_ty auge;
+
+	assert(s->kind == AugAssign_kind);
+
+	switch (e->kind) {
+	case Attribute_kind:
+		auge = Attribute(e->v.Attribute.value, e->v.Attribute.attr,
+				 AugLoad, e->lineno, e->col_offset, c->c_arena);
+		if (auge == NULL)
+		    return 0;
+		VISIT(c, expr, auge);
+		VISIT(c, expr, s->v.AugAssign.value);
+		ADDOP(c, inplace_binop(c, s->v.AugAssign.op));
+		auge->v.Attribute.ctx = AugStore;
+		VISIT(c, expr, auge);
+		break;
+	case Subscript_kind:
+		auge = Subscript(e->v.Subscript.value, e->v.Subscript.slice,
+				 AugLoad, e->lineno, e->col_offset, c->c_arena);
+		if (auge == NULL)
+		    return 0;
+		VISIT(c, expr, auge);
+		VISIT(c, expr, s->v.AugAssign.value);
+		ADDOP(c, inplace_binop(c, s->v.AugAssign.op));
+		auge->v.Subscript.ctx = AugStore;
+		VISIT(c, expr, auge);
+		break;
+	case Name_kind:
+		if (!compiler_nameop(c, e->v.Name.id, Load))
+		    return 0;
+		VISIT(c, expr, s->v.AugAssign.value);
+		ADDOP(c, inplace_binop(c, s->v.AugAssign.op));
+		return compiler_nameop(c, e->v.Name.id, Store);
+	default:
+		PyErr_Format(PyExc_SystemError, 
+			"invalid node type (%d) for augmented assignment",
+			e->kind);
+		return 0;
+	}
+	return 1;
+}
+
+static int
+compiler_push_fblock(struct compiler *c, enum fblocktype t, basicblock *b)
+{
+	struct fblockinfo *f;
+	if (c->u->u_nfblocks >= CO_MAXBLOCKS) {
+		PyErr_SetString(PyExc_SystemError,
+				"too many statically nested blocks");
+		return 0;
+	}
+	f = &c->u->u_fblock[c->u->u_nfblocks++];
+	f->fb_type = t;
+	f->fb_block = b;
+	return 1;
+}
+
+static void
+compiler_pop_fblock(struct compiler *c, enum fblocktype t, basicblock *b)
+{
+	struct compiler_unit *u = c->u;
+	assert(u->u_nfblocks > 0);
+	u->u_nfblocks--;
+	assert(u->u_fblock[u->u_nfblocks].fb_type == t);
+	assert(u->u_fblock[u->u_nfblocks].fb_block == b);
+}
+
+static int
+compiler_in_loop(struct compiler *c) {
+        int i;
+        struct compiler_unit *u = c->u;
+        for (i = 0; i < u->u_nfblocks; ++i) {
+                if (u->u_fblock[i].fb_type == LOOP)
+                        return 1;
+        }
+        return 0;
+}
+/* Raises a SyntaxError and returns 0.
+   If something goes wrong, a different exception may be raised.
+*/
+
+static int
+compiler_error(struct compiler *c, const char *errstr)
+{
+	PyObject *loc;
+	PyObject *u = NULL, *v = NULL;
+
+	loc = PyErr_ProgramText(c->c_filename, c->u->u_lineno);
+	if (!loc) {
+		Py_INCREF(Py_None);
+		loc = Py_None;
+	}
+	u = Py_BuildValue("(ziOO)", c->c_filename, c->u->u_lineno,
+			  Py_None, loc);
+	if (!u)
+		goto exit;
+	v = Py_BuildValue("(zO)", errstr, u);
+	if (!v)
+		goto exit;
+	PyErr_SetObject(PyExc_SyntaxError, v);
+ exit:
+	Py_DECREF(loc);
+	Py_XDECREF(u);
+	Py_XDECREF(v);
+	return 0;
+}
+
+static int
+compiler_handle_subscr(struct compiler *c, const char *kind, 
+		       expr_context_ty ctx) 
+{
+	int op = 0;
+
+	/* XXX this code is duplicated */
+	switch (ctx) {
+		case AugLoad: /* fall through to Load */
+		case Load:    op = BINARY_SUBSCR; break;
+		case AugStore:/* fall through to Store */
+		case Store:   op = STORE_SUBSCR; break;
+		case Del:     op = DELETE_SUBSCR; break;
+		case Param:
+			PyErr_Format(PyExc_SystemError, 
+				     "invalid %s kind %d in subscript\n", 
+				     kind, ctx);
+			return 0;
+	}
+	if (ctx == AugLoad) {
+		ADDOP_I(c, DUP_TOPX, 2);
+	}
+	else if (ctx == AugStore) {
+		ADDOP(c, ROT_THREE);
+	}
+	ADDOP(c, op);
+	return 1;
+}
+
+static int
+compiler_slice(struct compiler *c, slice_ty s, expr_context_ty ctx)
+{
+	int n = 2;
+	assert(s->kind == Slice_kind);
+
+	/* only handles the cases where BUILD_SLICE is emitted */
+	if (s->v.Slice.lower) {
+		VISIT(c, expr, s->v.Slice.lower);
+	}
+	else {
+		ADDOP_O(c, LOAD_CONST, Py_None, consts);
+	}
+		
+	if (s->v.Slice.upper) {
+		VISIT(c, expr, s->v.Slice.upper);
+	}
+	else {
+		ADDOP_O(c, LOAD_CONST, Py_None, consts);
+	}
+
+	if (s->v.Slice.step) {
+		n++;
+		VISIT(c, expr, s->v.Slice.step);
+	}
+	ADDOP_I(c, BUILD_SLICE, n);
+	return 1;
+}
+
+static int
+compiler_simple_slice(struct compiler *c, slice_ty s, expr_context_ty ctx)
+{
+	int op = 0, slice_offset = 0, stack_count = 0;
+
+	assert(s->v.Slice.step == NULL);
+	if (s->v.Slice.lower) {
+		slice_offset++;
+		stack_count++;
+		if (ctx != AugStore) 
+			VISIT(c, expr, s->v.Slice.lower);
+	}
+	if (s->v.Slice.upper) {
+		slice_offset += 2;
+		stack_count++;
+		if (ctx != AugStore) 
+			VISIT(c, expr, s->v.Slice.upper);
+	}
+
+	if (ctx == AugLoad) {
+		switch (stack_count) {
+		case 0: ADDOP(c, DUP_TOP); break;
+		case 1: ADDOP_I(c, DUP_TOPX, 2); break;
+		case 2: ADDOP_I(c, DUP_TOPX, 3); break;
+		}
+	}
+	else if (ctx == AugStore) {
+		switch (stack_count) {
+		case 0: ADDOP(c, ROT_TWO); break;
+		case 1: ADDOP(c, ROT_THREE); break;
+		case 2: ADDOP(c, ROT_FOUR); break;
+		}
+	}
+
+	switch (ctx) {
+	case AugLoad: /* fall through to Load */
+	case Load: op = SLICE; break;
+	case AugStore:/* fall through to Store */
+	case Store: op = STORE_SLICE; break;
+	case Del: op = DELETE_SLICE; break;
+	case Param:
+	default:
+		PyErr_SetString(PyExc_SystemError,
+				"param invalid in simple slice");
+		return 0;
+	}
+
+	ADDOP(c, op + slice_offset);
+	return 1;
+}
+
+static int
+compiler_visit_nested_slice(struct compiler *c, slice_ty s, 
+			    expr_context_ty ctx)
+{
+	switch (s->kind) {
+	case Ellipsis_kind:
+		ADDOP_O(c, LOAD_CONST, Py_Ellipsis, consts);
+		break;
+	case Slice_kind:
+		return compiler_slice(c, s, ctx);
+	case Index_kind:
+		VISIT(c, expr, s->v.Index.value);
+		break;
+	case ExtSlice_kind:
+	default:
+		PyErr_SetString(PyExc_SystemError,
+				"extended slice invalid in nested slice");
+		return 0;
+	}
+	return 1;
+}
+
+
+static int
+compiler_visit_slice(struct compiler *c, slice_ty s, expr_context_ty ctx)
+{
+	char * kindname = NULL;
+	switch (s->kind) {
+	case Index_kind:
+		kindname = "index";
+		if (ctx != AugStore) {
+			VISIT(c, expr, s->v.Index.value);
+		}
+		break;
+	case Ellipsis_kind:
+		kindname = "ellipsis";
+		if (ctx != AugStore) {
+			ADDOP_O(c, LOAD_CONST, Py_Ellipsis, consts);
+		}
+		break;
+	case Slice_kind:
+		kindname = "slice";
+		if (!s->v.Slice.step) 
+			return compiler_simple_slice(c, s, ctx);
+		if (ctx != AugStore) {
+			if (!compiler_slice(c, s, ctx))
+				return 0;
+		}
+		break;
+	case ExtSlice_kind:
+		kindname = "extended slice";
+		if (ctx != AugStore) {
+			int i, n = asdl_seq_LEN(s->v.ExtSlice.dims);
+			for (i = 0; i < n; i++) {
+				slice_ty sub = (slice_ty)asdl_seq_GET(
+                                        s->v.ExtSlice.dims, i);
+				if (!compiler_visit_nested_slice(c, sub, ctx))
+					return 0;
+			}
+			ADDOP_I(c, BUILD_TUPLE, n);
+		}
+		break;
+	default:
+		PyErr_Format(PyExc_SystemError,
+			     "invalid subscript kind %d", s->kind);
+		return 0;
+	}
+	return compiler_handle_subscr(c, kindname, ctx);
+}
+
+/* do depth-first search of basic block graph, starting with block.
+   post records the block indices in post-order.
+
+   XXX must handle implicit jumps from one block to next
+*/
+
+static void
+dfs(struct compiler *c, basicblock *b, struct assembler *a)
+{
+	int i;
+	struct instr *instr = NULL;
+
+	if (b->b_seen)
+		return;
+	b->b_seen = 1;
+	if (b->b_next != NULL)
+		dfs(c, b->b_next, a);
+	for (i = 0; i < b->b_iused; i++) {
+		instr = &b->b_instr[i];
+		if (instr->i_jrel || instr->i_jabs)
+			dfs(c, instr->i_target, a);
+	}
+	a->a_postorder[a->a_nblocks++] = b;
+}
+
+static int
+stackdepth_walk(struct compiler *c, basicblock *b, int depth, int maxdepth)
+{
+	int i;
+	struct instr *instr;
+	if (b->b_seen || b->b_startdepth >= depth)
+		return maxdepth;
+	b->b_seen = 1;
+	b->b_startdepth = depth;
+	for (i = 0; i < b->b_iused; i++) {
+		instr = &b->b_instr[i];
+		depth += opcode_stack_effect(instr->i_opcode, instr->i_oparg);
+		if (depth > maxdepth)
+			maxdepth = depth;
+		assert(depth >= 0); /* invalid code or bug in stackdepth() */
+		if (instr->i_jrel || instr->i_jabs) {
+			maxdepth = stackdepth_walk(c, instr->i_target,
+						   depth, maxdepth);
+			if (instr->i_opcode == JUMP_ABSOLUTE ||
+			    instr->i_opcode == JUMP_FORWARD) {
+				goto out; /* remaining code is dead */
+			}
+		}
+	}
+	if (b->b_next)
+		maxdepth = stackdepth_walk(c, b->b_next, depth, maxdepth);
+out:
+	b->b_seen = 0;
+	return maxdepth;
+}
+
+/* Find the flow path that needs the largest stack.  We assume that
+ * cycles in the flow graph have no net effect on the stack depth.
+ */
+static int
+stackdepth(struct compiler *c)
+{
+	basicblock *b, *entryblock;
+	entryblock = NULL;
+	for (b = c->u->u_blocks; b != NULL; b = b->b_list) {
+		b->b_seen = 0;
+		b->b_startdepth = INT_MIN;
+		entryblock = b;
+	}
+	if (!entryblock)
+		return 0;
+	return stackdepth_walk(c, entryblock, 0, 0);
+}
+
+static int
+assemble_init(struct assembler *a, int nblocks, int firstlineno)
+{
+	memset(a, 0, sizeof(struct assembler));
+	a->a_lineno = firstlineno;
+	a->a_bytecode = PyString_FromStringAndSize(NULL, DEFAULT_CODE_SIZE);
+	if (!a->a_bytecode)
+		return 0;
+	a->a_lnotab = PyString_FromStringAndSize(NULL, DEFAULT_LNOTAB_SIZE);
+	if (!a->a_lnotab)
+		return 0;
+	a->a_postorder = (basicblock **)PyObject_Malloc(
+					    sizeof(basicblock *) * nblocks);
+	if (!a->a_postorder) {
+		PyErr_NoMemory();
+		return 0;
+	}
+	return 1;
+}
+
+static void
+assemble_free(struct assembler *a)
+{
+	Py_XDECREF(a->a_bytecode);
+	Py_XDECREF(a->a_lnotab);
+	if (a->a_postorder)
+		PyObject_Free(a->a_postorder);
+}
+
+/* Return the size of a basic block in bytes. */
+
+static int
+instrsize(struct instr *instr)
+{
+	if (!instr->i_hasarg)
+		return 1;
+	if (instr->i_oparg > 0xffff)
+		return 6;
+	return 3;
+}
+
+static int
+blocksize(basicblock *b)
+{
+	int i;
+	int size = 0;
+
+	for (i = 0; i < b->b_iused; i++)
+		size += instrsize(&b->b_instr[i]);
+	return size;
+}
+
+/* All about a_lnotab.
+
+c_lnotab is an array of unsigned bytes disguised as a Python string.
+It is used to map bytecode offsets to source code line #s (when needed
+for tracebacks).
+
+The array is conceptually a list of
+    (bytecode offset increment, line number increment)
+pairs.	The details are important and delicate, best illustrated by example:
+
+    byte code offset	source code line number
+	0		    1
+	6		    2
+       50		    7
+      350		  307
+      361		  308
+
+The first trick is that these numbers aren't stored, only the increments
+from one row to the next (this doesn't really work, but it's a start):
+
+    0, 1,  6, 1,  44, 5,  300, 300,  11, 1
+
+The second trick is that an unsigned byte can't hold negative values, or
+values larger than 255, so (a) there's a deep assumption that byte code
+offsets and their corresponding line #s both increase monotonically, and (b)
+if at least one column jumps by more than 255 from one row to the next, more
+than one pair is written to the table. In case #b, there's no way to know
+from looking at the table later how many were written.	That's the delicate
+part.  A user of c_lnotab desiring to find the source line number
+corresponding to a bytecode address A should do something like this
+
+    lineno = addr = 0
+    for addr_incr, line_incr in c_lnotab:
+	addr += addr_incr
+	if addr > A:
+	    return lineno
+	lineno += line_incr
+
+In order for this to work, when the addr field increments by more than 255,
+the line # increment in each pair generated must be 0 until the remaining addr
+increment is < 256.  So, in the example above, assemble_lnotab (it used
+to be called com_set_lineno) should not (as was actually done until 2.2)
+expand 300, 300 to 255, 255, 45, 45, 
+            but to 255,   0, 45, 255, 0, 45.
+*/
+
+static int
+assemble_lnotab(struct assembler *a, struct instr *i)
+{
+	int d_bytecode, d_lineno;
+	int len;
+	unsigned char *lnotab;
+
+	d_bytecode = a->a_offset - a->a_lineno_off;
+	d_lineno = i->i_lineno - a->a_lineno;
+
+	assert(d_bytecode >= 0);
+	assert(d_lineno >= 0);
+
+	/* XXX(nnorwitz): is there a better way to handle this?
+	   for loops are special, we want to be able to trace them
+	   each time around, so we need to set an extra line number. */
+	if (d_lineno == 0 && i->i_opcode != FOR_ITER)
+		return 1;
+
+	if (d_bytecode > 255) {
+		int j, nbytes, ncodes = d_bytecode / 255;
+		nbytes = a->a_lnotab_off + 2 * ncodes;
+		len = PyString_GET_SIZE(a->a_lnotab);
+		if (nbytes >= len) {
+			if (len * 2 < nbytes)
+				len = nbytes;
+			else
+				len *= 2;
+			if (_PyString_Resize(&a->a_lnotab, len) < 0)
+				return 0;
+		}
+		lnotab = (unsigned char *)
+			   PyString_AS_STRING(a->a_lnotab) + a->a_lnotab_off;
+		for (j = 0; j < ncodes; j++) {
+			*lnotab++ = 255;
+			*lnotab++ = 0;
+		}
+		d_bytecode -= ncodes * 255;
+		a->a_lnotab_off += ncodes * 2;
+	}
+	assert(d_bytecode <= 255);
+	if (d_lineno > 255) {
+		int j, nbytes, ncodes = d_lineno / 255;
+		nbytes = a->a_lnotab_off + 2 * ncodes;
+		len = PyString_GET_SIZE(a->a_lnotab);
+		if (nbytes >= len) {
+			if (len * 2 < nbytes)
+				len = nbytes;
+			else
+				len *= 2;
+			if (_PyString_Resize(&a->a_lnotab, len) < 0)
+				return 0;
+		}
+		lnotab = (unsigned char *)
+			   PyString_AS_STRING(a->a_lnotab) + a->a_lnotab_off;
+		*lnotab++ = d_bytecode;
+		*lnotab++ = 255;
+		d_bytecode = 0;
+		for (j = 1; j < ncodes; j++) {
+			*lnotab++ = 0;
+			*lnotab++ = 255;
+		}
+		d_lineno -= ncodes * 255;
+		a->a_lnotab_off += ncodes * 2;
+	}
+
+	len = PyString_GET_SIZE(a->a_lnotab);
+	if (a->a_lnotab_off + 2 >= len) {
+		if (_PyString_Resize(&a->a_lnotab, len * 2) < 0)
+			return 0;
+	}
+	lnotab = (unsigned char *)
+			PyString_AS_STRING(a->a_lnotab) + a->a_lnotab_off;
+
+	a->a_lnotab_off += 2;
+	if (d_bytecode) {
+		*lnotab++ = d_bytecode;
+		*lnotab++ = d_lineno;
+	}
+	else {	/* First line of a block; def stmt, etc. */
+		*lnotab++ = 0;
+		*lnotab++ = d_lineno;
+	}
+	a->a_lineno = i->i_lineno;
+	a->a_lineno_off = a->a_offset;
+	return 1;
+}
+
+/* assemble_emit()
+   Extend the bytecode with a new instruction.
+   Update lnotab if necessary.
+*/
+
+static int
+assemble_emit(struct assembler *a, struct instr *i)
+{
+	int size, arg = 0, ext = 0;
+	Py_ssize_t len = PyString_GET_SIZE(a->a_bytecode);
+	char *code;
+
+	size = instrsize(i);
+	if (i->i_hasarg) {
+		arg = i->i_oparg;
+		ext = arg >> 16;
+	}
+	if (i->i_lineno && !assemble_lnotab(a, i))
+		return 0;
+	if (a->a_offset + size >= len) {
+		if (_PyString_Resize(&a->a_bytecode, len * 2) < 0)
+		    return 0;
+	}
+	code = PyString_AS_STRING(a->a_bytecode) + a->a_offset;
+	a->a_offset += size;
+	if (size == 6) {
+		assert(i->i_hasarg);
+		*code++ = (char)EXTENDED_ARG;
+		*code++ = ext & 0xff;
+		*code++ = ext >> 8;
+		arg &= 0xffff;
+	}
+	*code++ = i->i_opcode;
+	if (i->i_hasarg) {
+		assert(size == 3 || size == 6);
+		*code++ = arg & 0xff;
+		*code++ = arg >> 8;
+	}
+	return 1;
+}
+
+static void
+assemble_jump_offsets(struct assembler *a, struct compiler *c)
+{
+	basicblock *b;
+	int bsize, totsize, extended_arg_count, last_extended_arg_count = 0;
+	int i;
+
+	/* Compute the size of each block and fixup jump args.
+	   Replace block pointer with position in bytecode. */
+start:
+	totsize = 0;
+	for (i = a->a_nblocks - 1; i >= 0; i--) {
+		b = a->a_postorder[i];
+		bsize = blocksize(b);
+		b->b_offset = totsize;
+		totsize += bsize;
+	}
+	extended_arg_count = 0;
+	for (b = c->u->u_blocks; b != NULL; b = b->b_list) {
+		bsize = b->b_offset;
+		for (i = 0; i < b->b_iused; i++) {
+			struct instr *instr = &b->b_instr[i];
+			/* Relative jumps are computed relative to
+			   the instruction pointer after fetching
+			   the jump instruction.
+			*/
+			bsize += instrsize(instr);
+			if (instr->i_jabs)
+				instr->i_oparg = instr->i_target->b_offset;
+			else if (instr->i_jrel) {
+				int delta = instr->i_target->b_offset - bsize;
+				instr->i_oparg = delta;
+			}
+			else
+				continue;
+			if (instr->i_oparg > 0xffff)
+				extended_arg_count++;
+		}
+	}
+
+	/* XXX: This is an awful hack that could hurt performance, but
+		on the bright side it should work until we come up
+		with a better solution.
+
+		In the meantime, should the goto be dropped in favor
+		of a loop?
+
+		The issue is that in the first loop blocksize() is called
+		which calls instrsize() which requires i_oparg be set
+		appropriately.	There is a bootstrap problem because
+		i_oparg is calculated in the second loop above.
+
+		So we loop until we stop seeing new EXTENDED_ARGs.
+		The only EXTENDED_ARGs that could be popping up are
+		ones in jump instructions.  So this should converge
+		fairly quickly.
+	*/
+	if (last_extended_arg_count != extended_arg_count) {
+		last_extended_arg_count = extended_arg_count;
+		goto start;
+	}
+}
+
+static PyObject *
+dict_keys_inorder(PyObject *dict, int offset)
+{
+	PyObject *tuple, *k, *v;
+	Py_ssize_t i, pos = 0, size = PyDict_Size(dict);
+
+	tuple = PyTuple_New(size);
+	if (tuple == NULL)
+		return NULL;
+	while (PyDict_Next(dict, &pos, &k, &v)) {
+		i = PyInt_AS_LONG(v);
+		k = PyTuple_GET_ITEM(k, 0);
+		Py_INCREF(k);
+		assert((i - offset) < size);
+		assert((i - offset) >= 0);
+		PyTuple_SET_ITEM(tuple, i - offset, k);
+	}
+	return tuple;
+}
+
+static int
+compute_code_flags(struct compiler *c)
+{
+	PySTEntryObject *ste = c->u->u_ste;
+	int flags = 0, n;
+	if (ste->ste_type != ModuleBlock)
+		flags |= CO_NEWLOCALS;
+	if (ste->ste_type == FunctionBlock) {
+		if (!ste->ste_unoptimized)
+			flags |= CO_OPTIMIZED;
+		if (ste->ste_nested)
+			flags |= CO_NESTED;
+		if (ste->ste_generator)
+			flags |= CO_GENERATOR;
+	}
+	if (ste->ste_varargs)
+		flags |= CO_VARARGS;
+	if (ste->ste_varkeywords)
+		flags |= CO_VARKEYWORDS;
+	if (ste->ste_generator)
+		flags |= CO_GENERATOR;
+
+	/* (Only) inherit compilerflags in PyCF_MASK */
+	flags |= (c->c_flags->cf_flags & PyCF_MASK);
+
+	n = PyDict_Size(c->u->u_freevars);
+	if (n < 0)
+	    return -1;
+	if (n == 0) {
+	    n = PyDict_Size(c->u->u_cellvars);
+	    if (n < 0)
+		return -1;
+	    if (n == 0) {
+		flags |= CO_NOFREE;
+	    }
+	}
+
+	return flags;
+}
+
+static PyCodeObject *
+makecode(struct compiler *c, struct assembler *a)
+{
+	PyObject *tmp;
+	PyCodeObject *co = NULL;
+	PyObject *consts = NULL;
+	PyObject *names = NULL;
+	PyObject *varnames = NULL;
+	PyObject *filename = NULL;
+	PyObject *name = NULL;
+	PyObject *freevars = NULL;
+	PyObject *cellvars = NULL;
+	PyObject *bytecode = NULL;
+	int nlocals, flags;
+
+	tmp = dict_keys_inorder(c->u->u_consts, 0);
+	if (!tmp)
+		goto error;
+	consts = PySequence_List(tmp); /* optimize_code requires a list */
+	Py_DECREF(tmp);
+
+	names = dict_keys_inorder(c->u->u_names, 0);
+	varnames = dict_keys_inorder(c->u->u_varnames, 0);
+	if (!consts || !names || !varnames)
+		goto error;
+      
+	cellvars = dict_keys_inorder(c->u->u_cellvars, 0);
+	if (!cellvars)
+	    goto error;
+	freevars = dict_keys_inorder(c->u->u_freevars, PyTuple_Size(cellvars));
+	if (!freevars)
+	    goto error;
+	filename = PyString_FromString(c->c_filename);
+	if (!filename)
+		goto error;
+
+	nlocals = PyDict_Size(c->u->u_varnames);
+	flags = compute_code_flags(c);
+	if (flags < 0)
+		goto error;
+
+	bytecode = optimize_code(a->a_bytecode, consts, names, a->a_lnotab);
+	if (!bytecode)
+		goto error;
+
+	tmp = PyList_AsTuple(consts); /* PyCode_New requires a tuple */
+	if (!tmp)
+		goto error;
+	Py_DECREF(consts);
+	consts = tmp;
+
+	co = PyCode_New(c->u->u_argcount, nlocals, stackdepth(c), flags,
+			bytecode, consts, names, varnames,
+			freevars, cellvars,
+			filename, c->u->u_name,
+			c->u->u_firstlineno,
+			a->a_lnotab);
+ error:
+	Py_XDECREF(consts);
+	Py_XDECREF(names);
+	Py_XDECREF(varnames);
+	Py_XDECREF(filename);
+	Py_XDECREF(name);
+	Py_XDECREF(freevars);
+	Py_XDECREF(cellvars);
+	Py_XDECREF(bytecode);
+	return co;
+}
+
+
+/* For debugging purposes only */
+#if 0
+static void
+dump_instr(const struct instr *i)
+{
+	const char *jrel = i->i_jrel ? "jrel " : "";
+	const char *jabs = i->i_jabs ? "jabs " : "";
+	char arg[128];
+
+	*arg = '\0';
+	if (i->i_hasarg)
+		sprintf(arg, "arg: %d ", i->i_oparg);
+
+	fprintf(stderr, "line: %d, opcode: %d %s%s%s\n", 
+			i->i_lineno, i->i_opcode, arg, jabs, jrel);
+}
+
+static void
+dump_basicblock(const basicblock *b)
+{
+	const char *seen = b->b_seen ? "seen " : "";
+	const char *b_return = b->b_return ? "return " : "";
+	fprintf(stderr, "used: %d, depth: %d, offset: %d %s%s\n",
+		b->b_iused, b->b_startdepth, b->b_offset, seen, b_return);
+	if (b->b_instr) {
+		int i;
+		for (i = 0; i < b->b_iused; i++) {
+			fprintf(stderr, "  [%02d] ", i);
+			dump_instr(b->b_instr + i);
+		}
+	}
+}
+#endif
+
+static PyCodeObject *
+assemble(struct compiler *c, int addNone)
+{
+	basicblock *b, *entryblock;
+	struct assembler a;
+	int i, j, nblocks;
+	PyCodeObject *co = NULL;
+
+	/* Make sure every block that falls off the end returns None.
+	   XXX NEXT_BLOCK() isn't quite right, because if the last
+	   block ends with a jump or return b_next shouldn't set.
+	 */
+	if (!c->u->u_curblock->b_return) {
+		NEXT_BLOCK(c);
+		if (addNone)
+			ADDOP_O(c, LOAD_CONST, Py_None, consts);
+		ADDOP(c, RETURN_VALUE);
+	}
+
+	nblocks = 0;
+	entryblock = NULL;
+	for (b = c->u->u_blocks; b != NULL; b = b->b_list) {
+		nblocks++;
+		entryblock = b; 
+	}
+
+	/* Set firstlineno if it wasn't explicitly set. */
+	if (!c->u->u_firstlineno) {
+		if (entryblock && entryblock->b_instr)
+			c->u->u_firstlineno = entryblock->b_instr->i_lineno;
+		else
+			c->u->u_firstlineno = 1;
+	}
+	if (!assemble_init(&a, nblocks, c->u->u_firstlineno))
+		goto error;
+	dfs(c, entryblock, &a);
+
+	/* Can't modify the bytecode after computing jump offsets. */
+	assemble_jump_offsets(&a, c);
+
+	/* Emit code in reverse postorder from dfs. */
+	for (i = a.a_nblocks - 1; i >= 0; i--) {
+		b = a.a_postorder[i];
+		for (j = 0; j < b->b_iused; j++)
+			if (!assemble_emit(&a, &b->b_instr[j]))
+				goto error;
+	}
+
+	if (_PyString_Resize(&a.a_lnotab, a.a_lnotab_off) < 0)
+		goto error;
+	if (_PyString_Resize(&a.a_bytecode, a.a_offset) < 0)
+		goto error;
+
+	co = makecode(c, &a);
+ error:
+	assemble_free(&a);
+	return co;
+}