cpython/Objects/frameobject.c

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/* Frame object implementation */
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#include "Python.h"
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#include "code.h"
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#include "frameobject.h"
#include "opcode.h"
#include "structmember.h"
#undef MIN
#undef MAX
#define MIN(a, b) ((a) < (b) ? (a) : (b))
#define MAX(a, b) ((a) > (b) ? (a) : (b))
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#define OFF(x) offsetof(PyFrameObject, x)
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static PyMemberDef frame_memberlist[] = {
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{"f_back", T_OBJECT, OFF(f_back), RO},
{"f_code", T_OBJECT, OFF(f_code), RO},
{"f_builtins", T_OBJECT, OFF(f_builtins),RO},
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{"f_globals", T_OBJECT, OFF(f_globals), RO},
{"f_lasti", T_INT, OFF(f_lasti), RO},
{"f_restricted",T_INT, OFF(f_restricted),RO},
{"f_exc_type", T_OBJECT, OFF(f_exc_type)},
{"f_exc_value", T_OBJECT, OFF(f_exc_value)},
{"f_exc_traceback", T_OBJECT, OFF(f_exc_traceback)},
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{NULL} /* Sentinel */
};
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static PyObject *
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frame_getlocals(PyFrameObject *f, void *closure)
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{
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PyFrame_FastToLocals(f);
Py_INCREF(f->f_locals);
return f->f_locals;
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}
static PyObject *
frame_getlineno(PyFrameObject *f, void *closure)
{
int lineno;
if (f->f_trace)
lineno = f->f_lineno;
else
lineno = PyCode_Addr2Line(f->f_code, f->f_lasti);
return PyInt_FromLong(lineno);
}
/* Setter for f_lineno - you can set f_lineno from within a trace function in
* order to jump to a given line of code, subject to some restrictions. Most
* lines are OK to jump to because they don't make any assumptions about the
* state of the stack (obvious because you could remove the line and the code
* would still work without any stack errors), but there are some constructs
* that limit jumping:
*
* o Lines with an 'except' statement on them can't be jumped to, because
* they expect an exception to be on the top of the stack.
* o Lines that live in a 'finally' block can't be jumped from or to, since
* the END_FINALLY expects to clean up the stack after the 'try' block.
* o 'try'/'for'/'while' blocks can't be jumped into because the blockstack
* needs to be set up before their code runs, and for 'for' loops the
* iterator needs to be on the stack.
*/
static int
frame_setlineno(PyFrameObject *f, PyObject* p_new_lineno)
{
int new_lineno = 0; /* The new value of f_lineno */
int new_lasti = 0; /* The new value of f_lasti */
int new_iblock = 0; /* The new value of f_iblock */
char *code = NULL; /* The bytecode for the frame... */
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Py_ssize_t code_len = 0; /* ...and its length */
char *lnotab = NULL; /* Iterating over co_lnotab */
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Py_ssize_t lnotab_len = 0; /* (ditto) */
int offset = 0; /* (ditto) */
int line = 0; /* (ditto) */
int addr = 0; /* (ditto) */
int min_addr = 0; /* Scanning the SETUPs and POPs */
int max_addr = 0; /* (ditto) */
int delta_iblock = 0; /* (ditto) */
int min_delta_iblock = 0; /* (ditto) */
int min_iblock = 0; /* (ditto) */
int f_lasti_setup_addr = 0; /* Policing no-jump-into-finally */
int new_lasti_setup_addr = 0; /* (ditto) */
int blockstack[CO_MAXBLOCKS]; /* Walking the 'finally' blocks */
int in_finally[CO_MAXBLOCKS]; /* (ditto) */
int blockstack_top = 0; /* (ditto) */
int setup_op = 0; /* (ditto) */
/* f_lineno must be an integer. */
if (!PyInt_Check(p_new_lineno)) {
PyErr_SetString(PyExc_ValueError,
"lineno must be an integer");
return -1;
}
/* You can only do this from within a trace function, not via
* _getframe or similar hackery. */
if (!f->f_trace)
{
PyErr_Format(PyExc_ValueError,
"f_lineno can only be set by a trace function");
return -1;
}
/* Fail if the line comes before the start of the code block. */
new_lineno = (int) PyInt_AsLong(p_new_lineno);
if (new_lineno < f->f_code->co_firstlineno) {
PyErr_Format(PyExc_ValueError,
"line %d comes before the current code block",
new_lineno);
return -1;
}
/* Find the bytecode offset for the start of the given line, or the
* first code-owning line after it. */
PyString_AsStringAndSize(f->f_code->co_lnotab, &lnotab, &lnotab_len);
addr = 0;
line = f->f_code->co_firstlineno;
new_lasti = -1;
for (offset = 0; offset < lnotab_len; offset += 2) {
addr += lnotab[offset];
line += lnotab[offset+1];
if (line >= new_lineno) {
new_lasti = addr;
new_lineno = line;
break;
}
}
/* If we didn't reach the requested line, return an error. */
if (new_lasti == -1) {
PyErr_Format(PyExc_ValueError,
"line %d comes after the current code block",
new_lineno);
return -1;
}
/* We're now ready to look at the bytecode. */
PyString_AsStringAndSize(f->f_code->co_code, &code, &code_len);
min_addr = MIN(new_lasti, f->f_lasti);
max_addr = MAX(new_lasti, f->f_lasti);
/* You can't jump onto a line with an 'except' statement on it -
* they expect to have an exception on the top of the stack, which
* won't be true if you jump to them. They always start with code
* that either pops the exception using POP_TOP (plain 'except:'
* lines do this) or duplicates the exception on the stack using
* DUP_TOP (if there's an exception type specified). See compile.c,
* 'com_try_except' for the full details. There aren't any other
* cases (AFAIK) where a line's code can start with DUP_TOP or
* POP_TOP, but if any ever appear, they'll be subject to the same
* restriction (but with a different error message). */
if (code[new_lasti] == DUP_TOP || code[new_lasti] == POP_TOP) {
PyErr_SetString(PyExc_ValueError,
"can't jump to 'except' line as there's no exception");
return -1;
}
/* You can't jump into or out of a 'finally' block because the 'try'
* block leaves something on the stack for the END_FINALLY to clean
* up. So we walk the bytecode, maintaining a simulated blockstack.
* When we reach the old or new address and it's in a 'finally' block
* we note the address of the corresponding SETUP_FINALLY. The jump
* is only legal if neither address is in a 'finally' block or
* they're both in the same one. 'blockstack' is a stack of the
* bytecode addresses of the SETUP_X opcodes, and 'in_finally' tracks
* whether we're in a 'finally' block at each blockstack level. */
f_lasti_setup_addr = -1;
new_lasti_setup_addr = -1;
memset(blockstack, '\0', sizeof(blockstack));
memset(in_finally, '\0', sizeof(in_finally));
blockstack_top = 0;
for (addr = 0; addr < code_len; addr++) {
unsigned char op = code[addr];
switch (op) {
case SETUP_LOOP:
case SETUP_EXCEPT:
case SETUP_FINALLY:
blockstack[blockstack_top++] = addr;
in_finally[blockstack_top-1] = 0;
break;
case POP_BLOCK:
assert(blockstack_top > 0);
setup_op = code[blockstack[blockstack_top-1]];
if (setup_op == SETUP_FINALLY) {
in_finally[blockstack_top-1] = 1;
}
else {
blockstack_top--;
}
break;
case END_FINALLY:
/* Ignore END_FINALLYs for SETUP_EXCEPTs - they exist
* in the bytecode but don't correspond to an actual
* 'finally' block. (If blockstack_top is 0, we must
* be seeing such an END_FINALLY.) */
if (blockstack_top > 0) {
setup_op = code[blockstack[blockstack_top-1]];
if (setup_op == SETUP_FINALLY) {
blockstack_top--;
}
}
break;
}
/* For the addresses we're interested in, see whether they're
* within a 'finally' block and if so, remember the address
* of the SETUP_FINALLY. */
if (addr == new_lasti || addr == f->f_lasti) {
int i = 0;
int setup_addr = -1;
for (i = blockstack_top-1; i >= 0; i--) {
if (in_finally[i]) {
setup_addr = blockstack[i];
break;
}
}
if (setup_addr != -1) {
if (addr == new_lasti) {
new_lasti_setup_addr = setup_addr;
}
if (addr == f->f_lasti) {
f_lasti_setup_addr = setup_addr;
}
}
}
if (op >= HAVE_ARGUMENT) {
addr += 2;
}
}
/* Verify that the blockstack tracking code didn't get lost. */
assert(blockstack_top == 0);
/* After all that, are we jumping into / out of a 'finally' block? */
if (new_lasti_setup_addr != f_lasti_setup_addr) {
PyErr_SetString(PyExc_ValueError,
"can't jump into or out of a 'finally' block");
return -1;
}
/* Police block-jumping (you can't jump into the middle of a block)
* and ensure that the blockstack finishes up in a sensible state (by
* popping any blocks we're jumping out of). We look at all the
* blockstack operations between the current position and the new
* one, and keep track of how many blocks we drop out of on the way.
* By also keeping track of the lowest blockstack position we see, we
* can tell whether the jump goes into any blocks without coming out
* again - in that case we raise an exception below. */
delta_iblock = 0;
for (addr = min_addr; addr < max_addr; addr++) {
unsigned char op = code[addr];
switch (op) {
case SETUP_LOOP:
case SETUP_EXCEPT:
case SETUP_FINALLY:
delta_iblock++;
break;
case POP_BLOCK:
delta_iblock--;
break;
}
min_delta_iblock = MIN(min_delta_iblock, delta_iblock);
if (op >= HAVE_ARGUMENT) {
addr += 2;
}
}
/* Derive the absolute iblock values from the deltas. */
min_iblock = f->f_iblock + min_delta_iblock;
if (new_lasti > f->f_lasti) {
/* Forwards jump. */
new_iblock = f->f_iblock + delta_iblock;
}
else {
/* Backwards jump. */
new_iblock = f->f_iblock - delta_iblock;
}
/* Are we jumping into a block? */
if (new_iblock > min_iblock) {
PyErr_SetString(PyExc_ValueError,
"can't jump into the middle of a block");
return -1;
}
/* Pop any blocks that we're jumping out of. */
while (f->f_iblock > new_iblock) {
PyTryBlock *b = &f->f_blockstack[--f->f_iblock];
while ((f->f_stacktop - f->f_valuestack) > b->b_level) {
PyObject *v = (*--f->f_stacktop);
Py_DECREF(v);
}
}
/* Finally set the new f_lineno and f_lasti and return OK. */
f->f_lineno = new_lineno;
f->f_lasti = new_lasti;
return 0;
}
static PyObject *
frame_gettrace(PyFrameObject *f, void *closure)
{
PyObject* trace = f->f_trace;
if (trace == NULL)
trace = Py_None;
Py_INCREF(trace);
return trace;
}
static int
frame_settrace(PyFrameObject *f, PyObject* v, void *closure)
{
/* We rely on f_lineno being accurate when f_trace is set. */
PyObject* old_value = f->f_trace;
Py_XINCREF(v);
f->f_trace = v;
if (v != NULL)
f->f_lineno = PyCode_Addr2Line(f->f_code, f->f_lasti);
Py_XDECREF(old_value);
return 0;
}
static PyGetSetDef frame_getsetlist[] = {
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{"f_locals", (getter)frame_getlocals, NULL, NULL},
{"f_lineno", (getter)frame_getlineno,
(setter)frame_setlineno, NULL},
{"f_trace", (getter)frame_gettrace, (setter)frame_settrace, NULL},
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{0}
};
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/* Stack frames are allocated and deallocated at a considerable rate.
In an attempt to improve the speed of function calls, we maintain a
separate free list of stack frames (just like integers are
allocated in a special way -- see intobject.c). When a stack frame
is on the free list, only the following members have a meaning:
ob_type == &Frametype
f_back next item on free list, or NULL
f_nlocals number of locals
f_stacksize size of value stack
ob_size size of localsplus
Note that the value and block stacks are preserved -- this can save
another malloc() call or two (and two free() calls as well!).
Also note that, unlike for integers, each frame object is a
malloc'ed object in its own right -- it is only the actual calls to
malloc() that we are trying to save here, not the administration.
After all, while a typical program may make millions of calls, a
call depth of more than 20 or 30 is probably already exceptional
unless the program contains run-away recursion. I hope.
Later, MAXFREELIST was added to bound the # of frames saved on
free_list. Else programs creating lots of cyclic trash involving
frames could provoke free_list into growing without bound.
*/
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static PyFrameObject *free_list = NULL;
static int numfree = 0; /* number of frames currently in free_list */
#define MAXFREELIST 200 /* max value for numfree */
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static void
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frame_dealloc(PyFrameObject *f)
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{
int i, slots;
PyObject **fastlocals;
PyObject **p;
PyObject_GC_UnTrack(f);
Py_TRASHCAN_SAFE_BEGIN(f)
/* Kill all local variables */
slots = f->f_nlocals + f->f_ncells + f->f_nfreevars;
fastlocals = f->f_localsplus;
for (i = slots; --i >= 0; ++fastlocals) {
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Py_XDECREF(*fastlocals);
}
/* Free stack */
if (f->f_stacktop != NULL) {
for (p = f->f_valuestack; p < f->f_stacktop; p++)
Py_XDECREF(*p);
}
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Py_XDECREF(f->f_back);
Py_DECREF(f->f_code);
Py_DECREF(f->f_builtins);
Py_DECREF(f->f_globals);
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Py_XDECREF(f->f_locals);
Py_XDECREF(f->f_trace);
Py_XDECREF(f->f_exc_type);
Py_XDECREF(f->f_exc_value);
Py_XDECREF(f->f_exc_traceback);
if (numfree < MAXFREELIST) {
++numfree;
f->f_back = free_list;
free_list = f;
}
else
PyObject_GC_Del(f);
Py_TRASHCAN_SAFE_END(f)
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}
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static int
frame_traverse(PyFrameObject *f, visitproc visit, void *arg)
{
PyObject **fastlocals, **p;
int i, err, slots;
#define VISIT(o) if (o) {if ((err = visit((PyObject *)(o), arg))) return err;}
VISIT(f->f_back);
VISIT(f->f_code);
VISIT(f->f_builtins);
VISIT(f->f_globals);
VISIT(f->f_locals);
VISIT(f->f_trace);
VISIT(f->f_exc_type);
VISIT(f->f_exc_value);
VISIT(f->f_exc_traceback);
/* locals */
slots = f->f_nlocals + f->f_ncells + f->f_nfreevars;
fastlocals = f->f_localsplus;
for (i = slots; --i >= 0; ++fastlocals) {
VISIT(*fastlocals);
}
/* stack */
if (f->f_stacktop != NULL) {
for (p = f->f_valuestack; p < f->f_stacktop; p++)
VISIT(*p);
}
return 0;
}
static void
frame_clear(PyFrameObject *f)
{
PyObject **fastlocals, **p;
int i, slots;
Py_XDECREF(f->f_exc_type);
f->f_exc_type = NULL;
Py_XDECREF(f->f_exc_value);
f->f_exc_value = NULL;
Py_XDECREF(f->f_exc_traceback);
f->f_exc_traceback = NULL;
Py_XDECREF(f->f_trace);
f->f_trace = NULL;
/* locals */
slots = f->f_nlocals + f->f_ncells + f->f_nfreevars;
fastlocals = f->f_localsplus;
for (i = slots; --i >= 0; ++fastlocals) {
if (*fastlocals != NULL) {
Py_XDECREF(*fastlocals);
*fastlocals = NULL;
}
}
/* stack */
if (f->f_stacktop != NULL) {
for (p = f->f_valuestack; p < f->f_stacktop; p++) {
Py_XDECREF(*p);
*p = NULL;
}
}
}
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PyTypeObject PyFrame_Type = {
PyObject_HEAD_INIT(&PyType_Type)
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0,
"frame",
sizeof(PyFrameObject),
sizeof(PyObject *),
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(destructor)frame_dealloc, /* tp_dealloc */
0, /* tp_print */
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0, /* tp_getattr */
0, /* tp_setattr */
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0, /* tp_compare */
0, /* tp_repr */
0, /* tp_as_number */
0, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */
0, /* tp_str */
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PyObject_GenericGetAttr, /* tp_getattro */
PyObject_GenericSetAttr, /* tp_setattro */
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0, /* tp_as_buffer */
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,/* tp_flags */
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0, /* tp_doc */
(traverseproc)frame_traverse, /* tp_traverse */
(inquiry)frame_clear, /* tp_clear */
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0, /* tp_richcompare */
0, /* tp_weaklistoffset */
0, /* tp_iter */
0, /* tp_iternext */
0, /* tp_methods */
frame_memberlist, /* tp_members */
frame_getsetlist, /* tp_getset */
0, /* tp_base */
0, /* tp_dict */
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};
static PyObject *builtin_object;
int _PyFrame_Init()
{
builtin_object = PyString_InternFromString("__builtins__");
return (builtin_object != NULL);
}
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PyFrameObject *
PEP 227 implementation The majority of the changes are in the compiler. The mainloop changes primarily to implement the new opcodes and to pass a function's closure to eval_code2(). Frames and functions got new slots to hold the closure. Include/compile.h Add co_freevars and co_cellvars slots to code objects. Update PyCode_New() to take freevars and cellvars as arguments Include/funcobject.h Add func_closure slot to function objects. Add GetClosure()/SetClosure() functions (and corresponding macros) for getting at the closure. Include/frameobject.h PyFrame_New() now takes a closure. Include/opcode.h Add four new opcodes: MAKE_CLOSURE, LOAD_CLOSURE, LOAD_DEREF, STORE_DEREF. Remove comment about old requirement for opcodes to fit in 7 bits. compile.c Implement changes to code objects for co_freevars and co_cellvars. Modify symbol table to use st_cur_name (string object for the name of the current scope) and st_cur_children (list of nested blocks). Also define st_nested, which might more properly be called st_cur_nested. Add several DEF_XXX flags to track def-use information for free variables. New or modified functions of note: com_make_closure(struct compiling *, PyCodeObject *) Emit LOAD_CLOSURE opcodes as needed to pass cells for free variables into nested scope. com_addop_varname(struct compiling *, int, char *) Emits opcodes for LOAD_DEREF and STORE_DEREF. get_ref_type(struct compiling *, char *name) Return NAME_CLOSURE if ref type is FREE or CELL symtable_load_symbols(struct compiling *) Decides what variables are cell or free based on def-use info. Can now raise SyntaxError if nested scopes are mixed with exec or from blah import *. make_scope_info(PyObject *, PyObject *, int, int) Helper functions for symtable scope stack. symtable_update_free_vars(struct symtable *) After a code block has been analyzed, it must check each of its children for free variables that are not defined in the block. If a variable is free in a child and not defined in the parent, then it is defined by block the enclosing the current one or it is a global. This does the right logic. symtable_add_use() is now a macro for symtable_add_def() symtable_assign(struct symtable *, node *) Use goto instead of for (;;) Fixed bug in symtable where name of keyword argument in function call was treated as assignment in the scope of the call site. Ex: def f(): g(a=2) # a was considered a local of f ceval.c eval_code2() now take one more argument, a closure. Implement LOAD_CLOSURE, LOAD_DEREF, STORE_DEREF, MAKE_CLOSURE> Also: When name error occurs for global variable, report that the name was global in the error mesage. Objects/frameobject.c Initialize f_closure to be a tuple containing space for cellvars and freevars. f_closure is NULL if neither are present. Objects/funcobject.c Add support for func_closure. Python/import.c Change the magic number. Python/marshal.c Track changes to code objects.
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PyFrame_New(PyThreadState *tstate, PyCodeObject *code, PyObject *globals,
PyObject *locals)
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{
PyFrameObject *back = tstate->frame;
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PyFrameObject *f;
PyObject *builtins;
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Py_ssize_t extras, ncells, nfrees, i;
#ifdef Py_DEBUG
if (code == NULL || globals == NULL || !PyDict_Check(globals) ||
(locals != NULL && !PyMapping_Check(locals))) {
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PyErr_BadInternalCall();
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return NULL;
}
#endif
PEP 227 implementation The majority of the changes are in the compiler. The mainloop changes primarily to implement the new opcodes and to pass a function's closure to eval_code2(). Frames and functions got new slots to hold the closure. Include/compile.h Add co_freevars and co_cellvars slots to code objects. Update PyCode_New() to take freevars and cellvars as arguments Include/funcobject.h Add func_closure slot to function objects. Add GetClosure()/SetClosure() functions (and corresponding macros) for getting at the closure. Include/frameobject.h PyFrame_New() now takes a closure. Include/opcode.h Add four new opcodes: MAKE_CLOSURE, LOAD_CLOSURE, LOAD_DEREF, STORE_DEREF. Remove comment about old requirement for opcodes to fit in 7 bits. compile.c Implement changes to code objects for co_freevars and co_cellvars. Modify symbol table to use st_cur_name (string object for the name of the current scope) and st_cur_children (list of nested blocks). Also define st_nested, which might more properly be called st_cur_nested. Add several DEF_XXX flags to track def-use information for free variables. New or modified functions of note: com_make_closure(struct compiling *, PyCodeObject *) Emit LOAD_CLOSURE opcodes as needed to pass cells for free variables into nested scope. com_addop_varname(struct compiling *, int, char *) Emits opcodes for LOAD_DEREF and STORE_DEREF. get_ref_type(struct compiling *, char *name) Return NAME_CLOSURE if ref type is FREE or CELL symtable_load_symbols(struct compiling *) Decides what variables are cell or free based on def-use info. Can now raise SyntaxError if nested scopes are mixed with exec or from blah import *. make_scope_info(PyObject *, PyObject *, int, int) Helper functions for symtable scope stack. symtable_update_free_vars(struct symtable *) After a code block has been analyzed, it must check each of its children for free variables that are not defined in the block. If a variable is free in a child and not defined in the parent, then it is defined by block the enclosing the current one or it is a global. This does the right logic. symtable_add_use() is now a macro for symtable_add_def() symtable_assign(struct symtable *, node *) Use goto instead of for (;;) Fixed bug in symtable where name of keyword argument in function call was treated as assignment in the scope of the call site. Ex: def f(): g(a=2) # a was considered a local of f ceval.c eval_code2() now take one more argument, a closure. Implement LOAD_CLOSURE, LOAD_DEREF, STORE_DEREF, MAKE_CLOSURE> Also: When name error occurs for global variable, report that the name was global in the error mesage. Objects/frameobject.c Initialize f_closure to be a tuple containing space for cellvars and freevars. f_closure is NULL if neither are present. Objects/funcobject.c Add support for func_closure. Python/import.c Change the magic number. Python/marshal.c Track changes to code objects.
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ncells = PyTuple_GET_SIZE(code->co_cellvars);
nfrees = PyTuple_GET_SIZE(code->co_freevars);
extras = code->co_stacksize + code->co_nlocals + ncells + nfrees;
if (back == NULL || back->f_globals != globals) {
builtins = PyDict_GetItem(globals, builtin_object);
if (builtins) {
if (PyModule_Check(builtins)) {
builtins = PyModule_GetDict(builtins);
assert(!builtins || PyDict_Check(builtins));
}
else if (!PyDict_Check(builtins))
builtins = NULL;
}
if (builtins == NULL) {
/* No builtins! Make up a minimal one
Give them 'None', at least. */
builtins = PyDict_New();
if (builtins == NULL ||
PyDict_SetItemString(
builtins, "None", Py_None) < 0)
return NULL;
}
else
Py_INCREF(builtins);
}
else {
/* If we share the globals, we share the builtins.
Save a lookup and a call. */
builtins = back->f_builtins;
assert(builtins != NULL && PyDict_Check(builtins));
Py_INCREF(builtins);
}
if (free_list == NULL) {
f = PyObject_GC_NewVar(PyFrameObject, &PyFrame_Type, extras);
if (f == NULL) {
Py_DECREF(builtins);
return NULL;
}
}
else {
assert(numfree > 0);
--numfree;
f = free_list;
free_list = free_list->f_back;
if (f->ob_size < extras) {
f = PyObject_GC_Resize(PyFrameObject, f, extras);
if (f == NULL) {
Py_DECREF(builtins);
return NULL;
}
}
_Py_NewReference((PyObject *)f);
}
f->f_builtins = builtins;
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Py_XINCREF(back);
f->f_back = back;
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Py_INCREF(code);
f->f_code = code;
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Py_INCREF(globals);
f->f_globals = globals;
/* Most functions have CO_NEWLOCALS and CO_OPTIMIZED set. */
if ((code->co_flags & (CO_NEWLOCALS | CO_OPTIMIZED)) ==
(CO_NEWLOCALS | CO_OPTIMIZED))
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locals = NULL; /* PyFrame_FastToLocals() will set. */
else if (code->co_flags & CO_NEWLOCALS) {
locals = PyDict_New();
if (locals == NULL) {
Py_DECREF(f);
return NULL;
}
}
else {
if (locals == NULL)
locals = globals;
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Py_INCREF(locals);
}
f->f_locals = locals;
f->f_trace = NULL;
f->f_exc_type = f->f_exc_value = f->f_exc_traceback = NULL;
f->f_tstate = tstate;
f->f_lasti = -1;
f->f_lineno = code->co_firstlineno;
f->f_restricted = (builtins != tstate->interp->builtins);
f->f_iblock = 0;
f->f_nlocals = code->co_nlocals;
f->f_stacksize = code->co_stacksize;
f->f_ncells = ncells;
f->f_nfreevars = nfrees;
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extras = f->f_nlocals + ncells + nfrees;
/* Tim said it's ok to replace memset */
for (i=0; i<extras; i++)
f->f_localsplus[i] = NULL;
f->f_valuestack = f->f_localsplus + extras;
f->f_stacktop = f->f_valuestack;
_PyObject_GC_TRACK(f);
return f;
}
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/* Block management */
void
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PyFrame_BlockSetup(PyFrameObject *f, int type, int handler, int level)
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{
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PyTryBlock *b;
if (f->f_iblock >= CO_MAXBLOCKS)
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Py_FatalError("XXX block stack overflow");
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b = &f->f_blockstack[f->f_iblock++];
b->b_type = type;
b->b_level = level;
b->b_handler = handler;
}
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PyTryBlock *
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PyFrame_BlockPop(PyFrameObject *f)
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{
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PyTryBlock *b;
if (f->f_iblock <= 0)
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Py_FatalError("XXX block stack underflow");
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b = &f->f_blockstack[--f->f_iblock];
return b;
}
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/* Convert between "fast" version of locals and dictionary version */
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static void
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map_to_dict(PyObject *map, Py_ssize_t nmap, PyObject *dict, PyObject **values,
Py_ssize_t deref)
{
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Py_ssize_t j;
for (j = nmap; --j >= 0; ) {
PyObject *key = PyTuple_GET_ITEM(map, j);
PyObject *value = values[j];
if (deref)
value = PyCell_GET(value);
if (value == NULL) {
if (PyObject_DelItem(dict, key) != 0)
PyErr_Clear();
}
else {
if (PyObject_SetItem(dict, key, value) != 0)
PyErr_Clear();
}
}
}
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static void
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dict_to_map(PyObject *map, Py_ssize_t nmap, PyObject *dict, PyObject **values,
Py_ssize_t deref, int clear)
{
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Py_ssize_t j;
for (j = nmap; --j >= 0; ) {
PyObject *key = PyTuple_GET_ITEM(map, j);
PyObject *value = PyObject_GetItem(dict, key);
if (value == NULL)
PyErr_Clear();
if (deref) {
if (value || clear) {
if (PyCell_GET(values[j]) != value) {
if (PyCell_Set(values[j], value) < 0)
PyErr_Clear();
}
}
} else if (value != NULL || clear) {
if (values[j] != value) {
Py_XINCREF(value);
Py_XDECREF(values[j]);
values[j] = value;
}
}
Py_XDECREF(value);
}
}
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void
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PyFrame_FastToLocals(PyFrameObject *f)
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{
/* Merge fast locals into f->f_locals */
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PyObject *locals, *map;
PyObject **fast;
PyObject *error_type, *error_value, *error_traceback;
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Py_ssize_t j;
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if (f == NULL)
return;
locals = f->f_locals;
if (locals == NULL) {
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locals = f->f_locals = PyDict_New();
if (locals == NULL) {
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PyErr_Clear(); /* Can't report it :-( */
return;
}
}
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map = f->f_code->co_varnames;
if (!PyTuple_Check(map))
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return;
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PyErr_Fetch(&error_type, &error_value, &error_traceback);
fast = f->f_localsplus;
j = PyTuple_GET_SIZE(map);
if (j > f->f_nlocals)
j = f->f_nlocals;
if (f->f_nlocals)
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map_to_dict(map, j, locals, fast, 0);
if (f->f_ncells || f->f_nfreevars) {
if (!(PyTuple_Check(f->f_code->co_cellvars)
&& PyTuple_Check(f->f_code->co_freevars))) {
return;
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}
map_to_dict(f->f_code->co_cellvars,
PyTuple_GET_SIZE(f->f_code->co_cellvars),
locals, fast + f->f_nlocals, 1);
map_to_dict(f->f_code->co_freevars,
PyTuple_GET_SIZE(f->f_code->co_freevars),
locals, fast + f->f_nlocals + f->f_ncells, 1);
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}
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PyErr_Restore(error_type, error_value, error_traceback);
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}
void
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PyFrame_LocalsToFast(PyFrameObject *f, int clear)
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{
/* Merge f->f_locals into fast locals */
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PyObject *locals, *map;
PyObject **fast;
PyObject *error_type, *error_value, *error_traceback;
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Py_ssize_t j;
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if (f == NULL)
return;
locals = f->f_locals;
map = f->f_code->co_varnames;
if (locals == NULL)
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return;
if (!PyTuple_Check(map))
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return;
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PyErr_Fetch(&error_type, &error_value, &error_traceback);
fast = f->f_localsplus;
j = PyTuple_GET_SIZE(map);
if (j > f->f_nlocals)
j = f->f_nlocals;
if (f->f_nlocals)
dict_to_map(f->f_code->co_varnames, j, locals, fast, 0, clear);
if (f->f_ncells || f->f_nfreevars) {
if (!(PyTuple_Check(f->f_code->co_cellvars)
&& PyTuple_Check(f->f_code->co_freevars)))
return;
dict_to_map(f->f_code->co_cellvars,
PyTuple_GET_SIZE(f->f_code->co_cellvars),
locals, fast + f->f_nlocals, 1, clear);
dict_to_map(f->f_code->co_freevars,
PyTuple_GET_SIZE(f->f_code->co_freevars),
locals, fast + f->f_nlocals + f->f_ncells, 1,
clear);
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}
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PyErr_Restore(error_type, error_value, error_traceback);
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}
/* Clear out the free list */
void
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PyFrame_Fini(void)
{
while (free_list != NULL) {
PyFrameObject *f = free_list;
free_list = free_list->f_back;
PyObject_GC_Del(f);
--numfree;
}
assert(numfree == 0);
Py_XDECREF(builtin_object);
builtin_object = NULL;
}