/* Frame object implementation */ #include "Python.h" #include "pycore_ceval.h" // _PyEval_BuiltinsFromGlobals() #include "pycore_code.h" // CO_FAST_LOCAL, etc. #include "pycore_function.h" // _PyFunction_FromConstructor() #include "pycore_moduleobject.h" // _PyModule_GetDict() #include "pycore_object.h" // _PyObject_GC_UNTRACK() #include "pycore_opcode.h" // _PyOpcode_Caches #include "frameobject.h" // PyFrameObject #include "pycore_frame.h" #include "opcode.h" // EXTENDED_ARG #include "structmember.h" // PyMemberDef #define OFF(x) offsetof(PyFrameObject, x) static PyMemberDef frame_memberlist[] = { {"f_trace_lines", T_BOOL, OFF(f_trace_lines), 0}, {"f_trace_opcodes", T_BOOL, OFF(f_trace_opcodes), 0}, {NULL} /* Sentinel */ }; static PyObject * frame_getlocals(PyFrameObject *f, void *closure) { if (PyFrame_FastToLocalsWithError(f) < 0) return NULL; PyObject *locals = f->f_frame->f_locals; Py_INCREF(locals); return locals; } int PyFrame_GetLineNumber(PyFrameObject *f) { assert(f != NULL); if (f->f_lineno != 0) { return f->f_lineno; } else { return _PyInterpreterFrame_GetLine(f->f_frame); } } static PyObject * frame_getlineno(PyFrameObject *f, void *closure) { int lineno = PyFrame_GetLineNumber(f); if (lineno < 0) { Py_RETURN_NONE; } else { return PyLong_FromLong(lineno); } } static PyObject * frame_getlasti(PyFrameObject *f, void *closure) { int lasti = _PyInterpreterFrame_LASTI(f->f_frame); if (lasti < 0) { return PyLong_FromLong(-1); } return PyLong_FromLong(lasti * sizeof(_Py_CODEUNIT)); } static PyObject * frame_getglobals(PyFrameObject *f, void *closure) { PyObject *globals = f->f_frame->f_globals; if (globals == NULL) { globals = Py_None; } Py_INCREF(globals); return globals; } static PyObject * frame_getbuiltins(PyFrameObject *f, void *closure) { PyObject *builtins = f->f_frame->f_builtins; if (builtins == NULL) { builtins = Py_None; } Py_INCREF(builtins); return builtins; } static PyObject * frame_getcode(PyFrameObject *f, void *closure) { if (PySys_Audit("object.__getattr__", "Os", f, "f_code") < 0) { return NULL; } return (PyObject *)PyFrame_GetCode(f); } static PyObject * frame_getback(PyFrameObject *f, void *closure) { PyObject *res = (PyObject *)PyFrame_GetBack(f); if (res == NULL) { Py_RETURN_NONE; } return res; } // Given the index of the effective opcode, scan back to construct the oparg // with EXTENDED_ARG. This only works correctly with *unquickened* code, // obtained via a call to _PyCode_GetCode! static unsigned int get_arg(const _Py_CODEUNIT *codestr, Py_ssize_t i) { _Py_CODEUNIT word; unsigned int oparg = _Py_OPARG(codestr[i]); if (i >= 1 && _Py_OPCODE(word = codestr[i-1]) == EXTENDED_ARG) { oparg |= _Py_OPARG(word) << 8; if (i >= 2 && _Py_OPCODE(word = codestr[i-2]) == EXTENDED_ARG) { oparg |= _Py_OPARG(word) << 16; if (i >= 3 && _Py_OPCODE(word = codestr[i-3]) == EXTENDED_ARG) { oparg |= _Py_OPARG(word) << 24; } } } return oparg; } /* Model the evaluation stack, to determine which jumps * are safe and how many values needs to be popped. * The stack is modelled by a 64 integer, treating any * stack that can't fit into 64 bits as "overflowed". */ typedef enum kind { Iterator = 1, Except = 2, Object = 3, Null = 4, Lasti = 5, } Kind; static int compatible_kind(Kind from, Kind to) { if (to == 0) { return 0; } if (to == Object) { return from != Null; } if (to == Null) { return 1; } return from == to; } #define BITS_PER_BLOCK 3 #define UNINITIALIZED -2 #define OVERFLOWED -1 #define MAX_STACK_ENTRIES (63/BITS_PER_BLOCK) #define WILL_OVERFLOW (1ULL<<((MAX_STACK_ENTRIES-1)*BITS_PER_BLOCK)) #define EMPTY_STACK 0 static inline int64_t push_value(int64_t stack, Kind kind) { if (((uint64_t)stack) >= WILL_OVERFLOW) { return OVERFLOWED; } else { return (stack << BITS_PER_BLOCK) | kind; } } static inline int64_t pop_value(int64_t stack) { return Py_ARITHMETIC_RIGHT_SHIFT(int64_t, stack, BITS_PER_BLOCK); } #define MASK ((1<= 1); return (stack>>(BITS_PER_BLOCK*(n-1))) & MASK; } static Kind stack_swap(int64_t stack, int n) { assert(n >= 1); Kind to_swap = peek(stack, n); Kind top = top_of_stack(stack); int shift = BITS_PER_BLOCK*(n-1); int64_t replaced_low = (stack & ~(MASK << shift)) | (top << shift); int64_t replaced_top = (replaced_low & ~MASK) | to_swap; return replaced_top; } static int64_t pop_to_level(int64_t stack, int level) { if (level == 0) { return EMPTY_STACK; } int64_t max_item = (1< level_max_stack) { stack = pop_value(stack); } return stack; } #if 0 /* These functions are useful for debugging the stack marking code */ static char tos_char(int64_t stack) { switch(top_of_stack(stack)) { case Iterator: return 'I'; case Except: return 'E'; case Object: return 'O'; case Lasti: return 'L'; case Null: return 'N'; } return '?'; } static void print_stack(int64_t stack) { if (stack < 0) { if (stack == UNINITIALIZED) { printf("---"); } else if (stack == OVERFLOWED) { printf("OVERFLOWED"); } else { printf("??"); } return; } while (stack) { printf("%c", tos_char(stack)); stack = pop_value(stack); } } static void print_stacks(int64_t *stacks, int n) { for (int i = 0; i < n; i++) { printf("%d: ", i); print_stack(stacks[i]); printf("\n"); } } #endif static int64_t * mark_stacks(PyCodeObject *code_obj, int len) { PyObject *co_code = _PyCode_GetCode(code_obj); if (co_code == NULL) { return NULL; } _Py_CODEUNIT *code = (_Py_CODEUNIT *)PyBytes_AS_STRING(co_code); int64_t *stacks = PyMem_New(int64_t, len+1); int i, j, opcode; if (stacks == NULL) { PyErr_NoMemory(); Py_DECREF(co_code); return NULL; } for (int i = 1; i <= len; i++) { stacks[i] = UNINITIALIZED; } stacks[0] = EMPTY_STACK; if (code_obj->co_flags & (CO_GENERATOR | CO_COROUTINE | CO_ASYNC_GENERATOR)) { // Generators get sent None while starting: stacks[0] = push_value(stacks[0], Object); } int todo = 1; while (todo) { todo = 0; /* Scan instructions */ for (i = 0; i < len; i++) { int64_t next_stack = stacks[i]; if (next_stack == UNINITIALIZED) { continue; } opcode = _Py_OPCODE(code[i]); switch (opcode) { case JUMP_IF_FALSE_OR_POP: case JUMP_IF_TRUE_OR_POP: case POP_JUMP_IF_FALSE: case POP_JUMP_IF_TRUE: { int64_t target_stack; int j = get_arg(code, i); j += i + 1; assert(j < len); if (stacks[j] == UNINITIALIZED && j < i) { todo = 1; } if (opcode == JUMP_IF_FALSE_OR_POP || opcode == JUMP_IF_TRUE_OR_POP) { target_stack = next_stack; next_stack = pop_value(next_stack); } else { next_stack = pop_value(next_stack); target_stack = next_stack; } assert(stacks[j] == UNINITIALIZED || stacks[j] == target_stack); stacks[j] = target_stack; stacks[i+1] = next_stack; break; } case SEND: j = get_arg(code, i) + i + 1; assert(j < len); assert(stacks[j] == UNINITIALIZED || stacks[j] == pop_value(next_stack)); stacks[j] = pop_value(next_stack); stacks[i+1] = next_stack; break; case JUMP_FORWARD: j = get_arg(code, i) + i + 1; assert(j < len); assert(stacks[j] == UNINITIALIZED || stacks[j] == next_stack); stacks[j] = next_stack; break; case JUMP_BACKWARD: case JUMP_BACKWARD_NO_INTERRUPT: j = i + 1 - get_arg(code, i); assert(j >= 0); assert(j < len); if (stacks[j] == UNINITIALIZED && j < i) { todo = 1; } assert(stacks[j] == UNINITIALIZED || stacks[j] == next_stack); stacks[j] = next_stack; break; case GET_ITER: case GET_AITER: next_stack = push_value(pop_value(next_stack), Iterator); stacks[i+1] = next_stack; break; case FOR_ITER: { int64_t target_stack = pop_value(next_stack); stacks[i+1] = push_value(next_stack, Object); j = get_arg(code, i) + 1 + INLINE_CACHE_ENTRIES_FOR_ITER + i; assert(j < len); assert(stacks[j] == UNINITIALIZED || stacks[j] == target_stack); stacks[j] = target_stack; break; } case END_ASYNC_FOR: next_stack = pop_value(pop_value(next_stack)); stacks[i+1] = next_stack; break; case PUSH_EXC_INFO: next_stack = push_value(next_stack, Except); stacks[i+1] = next_stack; break; case POP_EXCEPT: assert(top_of_stack(next_stack) == Except); next_stack = pop_value(next_stack); stacks[i+1] = next_stack; break; case RETURN_VALUE: assert(pop_value(next_stack) == EMPTY_STACK); assert(top_of_stack(next_stack) == Object); break; case RAISE_VARARGS: break; case RERAISE: assert(top_of_stack(next_stack) == Except); /* End of block */ break; case PUSH_NULL: next_stack = push_value(next_stack, Null); stacks[i+1] = next_stack; break; case LOAD_GLOBAL: { int j = get_arg(code, i); if (j & 1) { next_stack = push_value(next_stack, Null); } next_stack = push_value(next_stack, Object); stacks[i+1] = next_stack; break; } case LOAD_ATTR: { assert(top_of_stack(next_stack) == Object); int j = get_arg(code, i); if (j & 1) { next_stack = pop_value(next_stack); next_stack = push_value(next_stack, Null); next_stack = push_value(next_stack, Object); } stacks[i+1] = next_stack; break; } case CALL: { int args = get_arg(code, i); for (int j = 0; j < args+2; j++) { next_stack = pop_value(next_stack); } next_stack = push_value(next_stack, Object); stacks[i+1] = next_stack; break; } case SWAP: { int n = get_arg(code, i); next_stack = stack_swap(next_stack, n); stacks[i+1] = next_stack; break; } case COPY: { int n = get_arg(code, i); next_stack = push_value(next_stack, peek(next_stack, n)); stacks[i+1] = next_stack; break; } default: { int delta = PyCompile_OpcodeStackEffect(opcode, get_arg(code, i)); assert(delta != PY_INVALID_STACK_EFFECT); while (delta < 0) { next_stack = pop_value(next_stack); delta++; } while (delta > 0) { next_stack = push_value(next_stack, Object); delta--; } stacks[i+1] = next_stack; } } } /* Scan exception table */ unsigned char *start = (unsigned char *)PyBytes_AS_STRING(code_obj->co_exceptiontable); unsigned char *end = start + PyBytes_GET_SIZE(code_obj->co_exceptiontable); unsigned char *scan = start; while (scan < end) { int start_offset, size, handler; scan = parse_varint(scan, &start_offset); assert(start_offset >= 0 && start_offset < len); scan = parse_varint(scan, &size); assert(size >= 0 && start_offset+size <= len); scan = parse_varint(scan, &handler); assert(handler >= 0 && handler < len); int depth_and_lasti; scan = parse_varint(scan, &depth_and_lasti); int level = depth_and_lasti >> 1; int lasti = depth_and_lasti & 1; if (stacks[start_offset] != UNINITIALIZED) { if (stacks[handler] == UNINITIALIZED) { todo = 1; uint64_t target_stack = pop_to_level(stacks[start_offset], level); if (lasti) { target_stack = push_value(target_stack, Lasti); } target_stack = push_value(target_stack, Except); stacks[handler] = target_stack; } } } } Py_DECREF(co_code); return stacks; } static int compatible_stack(int64_t from_stack, int64_t to_stack) { if (from_stack < 0 || to_stack < 0) { return 0; } while(from_stack > to_stack) { from_stack = pop_value(from_stack); } while(from_stack) { Kind from_top = top_of_stack(from_stack); Kind to_top = top_of_stack(to_stack); if (!compatible_kind(from_top, to_top)) { return 0; } from_stack = pop_value(from_stack); to_stack = pop_value(to_stack); } return to_stack == 0; } static const char * explain_incompatible_stack(int64_t to_stack) { assert(to_stack != 0); if (to_stack == OVERFLOWED) { return "stack is too deep to analyze"; } if (to_stack == UNINITIALIZED) { return "can't jump into an exception handler, or code may be unreachable"; } Kind target_kind = top_of_stack(to_stack); switch(target_kind) { case Except: return "can't jump into an 'except' block as there's no exception"; case Lasti: return "can't jump into a re-raising block as there's no location"; case Object: case Null: return "incompatible stacks"; case Iterator: return "can't jump into the body of a for loop"; default: Py_UNREACHABLE(); } } static int * marklines(PyCodeObject *code, int len) { PyCodeAddressRange bounds; _PyCode_InitAddressRange(code, &bounds); assert (bounds.ar_end == 0); int last_line = -1; int *linestarts = PyMem_New(int, len); if (linestarts == NULL) { return NULL; } for (int i = 0; i < len; i++) { linestarts[i] = -1; } while (_PyLineTable_NextAddressRange(&bounds)) { assert(bounds.ar_start / (int)sizeof(_Py_CODEUNIT) < len); if (bounds.ar_line != last_line && bounds.ar_line != -1) { linestarts[bounds.ar_start / sizeof(_Py_CODEUNIT)] = bounds.ar_line; last_line = bounds.ar_line; } } return linestarts; } static int first_line_not_before(int *lines, int len, int line) { int result = INT_MAX; for (int i = 0; i < len; i++) { if (lines[i] < result && lines[i] >= line) { result = lines[i]; } } if (result == INT_MAX) { return -1; } return result; } static PyFrameState _PyFrame_GetState(PyFrameObject *frame) { assert(!_PyFrame_IsIncomplete(frame->f_frame)); if (frame->f_frame->stacktop == 0) { return FRAME_CLEARED; } switch(frame->f_frame->owner) { case FRAME_OWNED_BY_GENERATOR: { PyGenObject *gen = _PyFrame_GetGenerator(frame->f_frame); return gen->gi_frame_state; } case FRAME_OWNED_BY_THREAD: { if (_PyInterpreterFrame_LASTI(frame->f_frame) < 0) { return FRAME_CREATED; } switch (_PyOpcode_Deopt[_Py_OPCODE(*frame->f_frame->prev_instr)]) { case COPY_FREE_VARS: case MAKE_CELL: case RETURN_GENERATOR: /* Frame not fully initialized */ return FRAME_CREATED; default: return FRAME_EXECUTING; } } case FRAME_OWNED_BY_FRAME_OBJECT: return FRAME_COMPLETED; } Py_UNREACHABLE(); } static void add_load_fast_null_checks(PyCodeObject *co) { int changed = 0; _Py_CODEUNIT *instructions = _PyCode_CODE(co); for (Py_ssize_t i = 0; i < Py_SIZE(co); i++) { int opcode = _Py_OPCODE(instructions[i]); switch (opcode) { case LOAD_FAST: case LOAD_FAST__LOAD_FAST: case LOAD_FAST__LOAD_CONST: changed = 1; _Py_SET_OPCODE(instructions[i], LOAD_FAST_CHECK); break; case LOAD_CONST__LOAD_FAST: changed = 1; _Py_SET_OPCODE(instructions[i], LOAD_CONST); break; case STORE_FAST__LOAD_FAST: changed = 1; _Py_SET_OPCODE(instructions[i], STORE_FAST); break; } i += _PyOpcode_Caches[_PyOpcode_Deopt[opcode]]; } if (changed && co->_co_cached != NULL) { // invalidate cached co_code object Py_CLEAR(co->_co_cached->_co_code); Py_CLEAR(co->_co_cached->_co_cellvars); Py_CLEAR(co->_co_cached->_co_freevars); Py_CLEAR(co->_co_cached->_co_varnames); PyMem_Free(co->_co_cached); co->_co_cached = NULL; } } /* 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 Any exception handlers. * o 'for' and 'async for' loops can't be jumped into because the * iterator needs to be on the stack. * o Jumps cannot be made from within a trace function invoked with a * 'return' or 'exception' event since the eval loop has been exited at * that time. */ static int frame_setlineno(PyFrameObject *f, PyObject* p_new_lineno, void *Py_UNUSED(ignored)) { if (p_new_lineno == NULL) { PyErr_SetString(PyExc_AttributeError, "cannot delete attribute"); return -1; } /* f_lineno must be an integer. */ if (!PyLong_CheckExact(p_new_lineno)) { PyErr_SetString(PyExc_ValueError, "lineno must be an integer"); return -1; } PyFrameState state = _PyFrame_GetState(f); /* * This code preserves the historical restrictions on * setting the line number of a frame. * Jumps are forbidden on a 'return' trace event (except after a yield). * Jumps from 'call' trace events are also forbidden. * In addition, jumps are forbidden when not tracing, * as this is a debugging feature. */ switch(PyThreadState_GET()->tracing_what) { case PyTrace_EXCEPTION: PyErr_SetString(PyExc_ValueError, "can only jump from a 'line' trace event"); return -1; case PyTrace_CALL: PyErr_Format(PyExc_ValueError, "can't jump from the 'call' trace event of a new frame"); return -1; case PyTrace_LINE: break; case PyTrace_RETURN: if (state == FRAME_SUSPENDED) { break; } /* fall through */ default: PyErr_SetString(PyExc_ValueError, "can only jump from a 'line' trace event"); return -1; } if (!f->f_trace) { PyErr_Format(PyExc_ValueError, "f_lineno can only be set by a trace function"); return -1; } int new_lineno; /* Fail if the line falls outside the code block and select first line with actual code. */ int overflow; long l_new_lineno = PyLong_AsLongAndOverflow(p_new_lineno, &overflow); if (overflow #if SIZEOF_LONG > SIZEOF_INT || l_new_lineno > INT_MAX || l_new_lineno < INT_MIN #endif ) { PyErr_SetString(PyExc_ValueError, "lineno out of range"); return -1; } new_lineno = (int)l_new_lineno; if (new_lineno < f->f_frame->f_code->co_firstlineno) { PyErr_Format(PyExc_ValueError, "line %d comes before the current code block", new_lineno); return -1; } add_load_fast_null_checks(f->f_frame->f_code); /* PyCode_NewWithPosOnlyArgs limits co_code to be under INT_MAX so this * should never overflow. */ int len = (int)Py_SIZE(f->f_frame->f_code); int *lines = marklines(f->f_frame->f_code, len); if (lines == NULL) { return -1; } new_lineno = first_line_not_before(lines, len, new_lineno); if (new_lineno < 0) { PyErr_Format(PyExc_ValueError, "line %d comes after the current code block", (int)l_new_lineno); PyMem_Free(lines); return -1; } int64_t *stacks = mark_stacks(f->f_frame->f_code, len); if (stacks == NULL) { PyMem_Free(lines); return -1; } int64_t best_stack = OVERFLOWED; int best_addr = -1; int64_t start_stack = stacks[_PyInterpreterFrame_LASTI(f->f_frame)]; int err = -1; const char *msg = "cannot find bytecode for specified line"; for (int i = 0; i < len; i++) { if (lines[i] == new_lineno) { int64_t target_stack = stacks[i]; if (compatible_stack(start_stack, target_stack)) { err = 0; if (target_stack > best_stack) { best_stack = target_stack; best_addr = i; } } else if (err < 0) { if (start_stack == OVERFLOWED) { msg = "stack to deep to analyze"; } else if (start_stack == UNINITIALIZED) { msg = "can't jump from unreachable code"; } else { msg = explain_incompatible_stack(target_stack); err = 1; } } } } PyMem_Free(stacks); PyMem_Free(lines); if (err) { PyErr_SetString(PyExc_ValueError, msg); return -1; } if (state == FRAME_SUSPENDED) { /* Account for value popped by yield */ start_stack = pop_value(start_stack); } while (start_stack > best_stack) { if (top_of_stack(start_stack) == Except) { /* Pop exception stack as well as the evaluation stack */ PyThreadState *tstate = _PyThreadState_GET(); _PyErr_StackItem *exc_info = tstate->exc_info; PyObject *value = exc_info->exc_value; PyObject *exc = _PyFrame_StackPop(f->f_frame); assert(PyExceptionInstance_Check(exc) || exc == Py_None); exc_info->exc_value = exc; Py_XDECREF(value); } else { PyObject *v = _PyFrame_StackPop(f->f_frame); Py_XDECREF(v); } start_stack = pop_value(start_stack); } /* Finally set the new lasti and return OK. */ f->f_lineno = 0; f->f_frame->prev_instr = _PyCode_CODE(f->f_frame->f_code) + best_addr; 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) { if (v == Py_None) { v = NULL; } Py_XINCREF(v); Py_XSETREF(f->f_trace, v); return 0; } static PyGetSetDef frame_getsetlist[] = { {"f_back", (getter)frame_getback, NULL, NULL}, {"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}, {"f_lasti", (getter)frame_getlasti, NULL, NULL}, {"f_globals", (getter)frame_getglobals, NULL, NULL}, {"f_builtins", (getter)frame_getbuiltins, NULL, NULL}, {"f_code", (getter)frame_getcode, NULL, NULL}, {0} }; /* 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 floats are allocated in a special way -- see floatobject.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 */ static void frame_dealloc(PyFrameObject *f) { /* It is the responsibility of the owning generator/coroutine * to have cleared the generator pointer */ assert(f->f_frame->owner != FRAME_OWNED_BY_GENERATOR || _PyFrame_GetGenerator(f->f_frame)->gi_frame_state == FRAME_CLEARED); if (_PyObject_GC_IS_TRACKED(f)) { _PyObject_GC_UNTRACK(f); } Py_TRASHCAN_BEGIN(f, frame_dealloc); PyCodeObject *co = NULL; /* Kill all local variables including specials, if we own them */ if (f->f_frame->owner == FRAME_OWNED_BY_FRAME_OBJECT) { assert(f->f_frame == (_PyInterpreterFrame *)f->_f_frame_data); _PyInterpreterFrame *frame = (_PyInterpreterFrame *)f->_f_frame_data; /* Don't clear code object until the end */ co = frame->f_code; frame->f_code = NULL; Py_CLEAR(frame->f_funcobj); Py_CLEAR(frame->f_locals); PyObject **locals = _PyFrame_GetLocalsArray(frame); for (int i = 0; i < frame->stacktop; i++) { Py_CLEAR(locals[i]); } } Py_CLEAR(f->f_back); Py_CLEAR(f->f_trace); PyObject_GC_Del(f); Py_XDECREF(co); Py_TRASHCAN_END; } static int frame_traverse(PyFrameObject *f, visitproc visit, void *arg) { Py_VISIT(f->f_back); Py_VISIT(f->f_trace); if (f->f_frame->owner != FRAME_OWNED_BY_FRAME_OBJECT) { return 0; } assert(f->f_frame->frame_obj == NULL); return _PyFrame_Traverse(f->f_frame, visit, arg); } static int frame_tp_clear(PyFrameObject *f) { Py_CLEAR(f->f_trace); /* locals and stack */ PyObject **locals = _PyFrame_GetLocalsArray(f->f_frame); assert(f->f_frame->stacktop >= 0); for (int i = 0; i < f->f_frame->stacktop; i++) { Py_CLEAR(locals[i]); } f->f_frame->stacktop = 0; return 0; } static PyObject * frame_clear(PyFrameObject *f, PyObject *Py_UNUSED(ignored)) { if (f->f_frame->owner == FRAME_OWNED_BY_GENERATOR) { PyGenObject *gen = _PyFrame_GetGenerator(f->f_frame); if (gen->gi_frame_state == FRAME_EXECUTING) { goto running; } _PyGen_Finalize((PyObject *)gen); } else if (f->f_frame->owner == FRAME_OWNED_BY_THREAD) { goto running; } else { assert(f->f_frame->owner == FRAME_OWNED_BY_FRAME_OBJECT); (void)frame_tp_clear(f); } Py_RETURN_NONE; running: PyErr_SetString(PyExc_RuntimeError, "cannot clear an executing frame"); return NULL; } PyDoc_STRVAR(clear__doc__, "F.clear(): clear most references held by the frame"); static PyObject * frame_sizeof(PyFrameObject *f, PyObject *Py_UNUSED(ignored)) { Py_ssize_t res; res = offsetof(PyFrameObject, _f_frame_data) + offsetof(_PyInterpreterFrame, localsplus); PyCodeObject *code = f->f_frame->f_code; res += (code->co_nlocalsplus+code->co_stacksize) * sizeof(PyObject *); return PyLong_FromSsize_t(res); } PyDoc_STRVAR(sizeof__doc__, "F.__sizeof__() -> size of F in memory, in bytes"); static PyObject * frame_repr(PyFrameObject *f) { int lineno = PyFrame_GetLineNumber(f); PyCodeObject *code = f->f_frame->f_code; return PyUnicode_FromFormat( "", f, code->co_filename, lineno, code->co_name); } static PyMethodDef frame_methods[] = { {"clear", (PyCFunction)frame_clear, METH_NOARGS, clear__doc__}, {"__sizeof__", (PyCFunction)frame_sizeof, METH_NOARGS, sizeof__doc__}, {NULL, NULL} /* sentinel */ }; PyTypeObject PyFrame_Type = { PyVarObject_HEAD_INIT(&PyType_Type, 0) "frame", offsetof(PyFrameObject, _f_frame_data) + offsetof(_PyInterpreterFrame, localsplus), sizeof(PyObject *), (destructor)frame_dealloc, /* tp_dealloc */ 0, /* tp_vectorcall_offset */ 0, /* tp_getattr */ 0, /* tp_setattr */ 0, /* tp_as_async */ (reprfunc)frame_repr, /* tp_repr */ 0, /* tp_as_number */ 0, /* tp_as_sequence */ 0, /* tp_as_mapping */ 0, /* tp_hash */ 0, /* tp_call */ 0, /* tp_str */ PyObject_GenericGetAttr, /* tp_getattro */ PyObject_GenericSetAttr, /* tp_setattro */ 0, /* tp_as_buffer */ Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,/* tp_flags */ 0, /* tp_doc */ (traverseproc)frame_traverse, /* tp_traverse */ (inquiry)frame_tp_clear, /* tp_clear */ 0, /* tp_richcompare */ 0, /* tp_weaklistoffset */ 0, /* tp_iter */ 0, /* tp_iternext */ frame_methods, /* tp_methods */ frame_memberlist, /* tp_members */ frame_getsetlist, /* tp_getset */ 0, /* tp_base */ 0, /* tp_dict */ }; static void init_frame(_PyInterpreterFrame *frame, PyFunctionObject *func, PyObject *locals) { /* _PyFrame_InitializeSpecials consumes reference to func */ Py_INCREF(func); Py_XINCREF(locals); PyCodeObject *code = (PyCodeObject *)func->func_code; _PyFrame_InitializeSpecials(frame, func, locals, code); for (Py_ssize_t i = 0; i < code->co_nlocalsplus; i++) { frame->localsplus[i] = NULL; } } PyFrameObject* _PyFrame_New_NoTrack(PyCodeObject *code) { CALL_STAT_INC(frame_objects_created); int slots = code->co_nlocalsplus + code->co_stacksize; PyFrameObject *f = PyObject_GC_NewVar(PyFrameObject, &PyFrame_Type, slots); if (f == NULL) { return NULL; } f->f_back = NULL; f->f_trace = NULL; f->f_trace_lines = 1; f->f_trace_opcodes = 0; f->f_fast_as_locals = 0; f->f_lineno = 0; return f; } /* Legacy API */ PyFrameObject* PyFrame_New(PyThreadState *tstate, PyCodeObject *code, PyObject *globals, PyObject *locals) { PyObject *builtins = _PyEval_BuiltinsFromGlobals(tstate, globals); // borrowed ref if (builtins == NULL) { return NULL; } PyFrameConstructor desc = { .fc_globals = globals, .fc_builtins = builtins, .fc_name = code->co_name, .fc_qualname = code->co_name, .fc_code = (PyObject *)code, .fc_defaults = NULL, .fc_kwdefaults = NULL, .fc_closure = NULL }; PyFunctionObject *func = _PyFunction_FromConstructor(&desc); if (func == NULL) { return NULL; } PyFrameObject *f = _PyFrame_New_NoTrack(code); if (f == NULL) { Py_DECREF(func); return NULL; } init_frame((_PyInterpreterFrame *)f->_f_frame_data, func, locals); f->f_frame = (_PyInterpreterFrame *)f->_f_frame_data; f->f_frame->owner = FRAME_OWNED_BY_FRAME_OBJECT; // This frame needs to be "complete", so pretend that the first RESUME ran: f->f_frame->prev_instr = _PyCode_CODE(code) + code->_co_firsttraceable; assert(!_PyFrame_IsIncomplete(f->f_frame)); Py_DECREF(func); _PyObject_GC_TRACK(f); return f; } static int _PyFrame_OpAlreadyRan(_PyInterpreterFrame *frame, int opcode, int oparg) { // This only works when opcode is a non-quickened form: assert(_PyOpcode_Deopt[opcode] == opcode); int check_oparg = 0; for (_Py_CODEUNIT *instruction = _PyCode_CODE(frame->f_code); instruction < frame->prev_instr; instruction++) { int check_opcode = _PyOpcode_Deopt[_Py_OPCODE(*instruction)]; check_oparg |= _Py_OPARG(*instruction); if (check_opcode == opcode && check_oparg == oparg) { return 1; } if (check_opcode == EXTENDED_ARG) { check_oparg <<= 8; } else { check_oparg = 0; } instruction += _PyOpcode_Caches[check_opcode]; } return 0; } int _PyFrame_FastToLocalsWithError(_PyInterpreterFrame *frame) { /* Merge fast locals into f->f_locals */ PyObject *locals; PyObject **fast; PyCodeObject *co; locals = frame->f_locals; if (locals == NULL) { locals = frame->f_locals = PyDict_New(); if (locals == NULL) return -1; } co = frame->f_code; fast = _PyFrame_GetLocalsArray(frame); // COPY_FREE_VARS has no quickened forms, so no need to use _PyOpcode_Deopt // here: int lasti = _PyInterpreterFrame_LASTI(frame); if (lasti < 0 && _Py_OPCODE(_PyCode_CODE(co)[0]) == COPY_FREE_VARS && PyFunction_Check(frame->f_funcobj)) { /* Free vars have not been initialized -- Do that */ PyCodeObject *co = frame->f_code; PyObject *closure = ((PyFunctionObject *)frame->f_funcobj)->func_closure; int offset = co->co_nlocals + co->co_nplaincellvars; for (int i = 0; i < co->co_nfreevars; ++i) { PyObject *o = PyTuple_GET_ITEM(closure, i); Py_INCREF(o); frame->localsplus[offset + i] = o; } // COPY_FREE_VARS doesn't have inline CACHEs, either: frame->prev_instr = _PyCode_CODE(frame->f_code); } for (int i = 0; i < co->co_nlocalsplus; i++) { _PyLocals_Kind kind = _PyLocals_GetKind(co->co_localspluskinds, i); /* If the namespace is unoptimized, then one of the following cases applies: 1. It does not contain free variables, because it uses import * or is a top-level namespace. 2. It is a class namespace. We don't want to accidentally copy free variables into the locals dict used by the class. */ if (kind & CO_FAST_FREE && !(co->co_flags & CO_OPTIMIZED)) { continue; } PyObject *name = PyTuple_GET_ITEM(co->co_localsplusnames, i); PyObject *value = fast[i]; if (frame->stacktop) { if (kind & CO_FAST_FREE) { // The cell was set by COPY_FREE_VARS. assert(value != NULL && PyCell_Check(value)); value = PyCell_GET(value); } else if (kind & CO_FAST_CELL) { // Note that no *_DEREF ops can happen before MAKE_CELL // executes. So there's no need to duplicate the work // that MAKE_CELL would otherwise do later, if it hasn't // run yet. if (value != NULL) { if (PyCell_Check(value) && _PyFrame_OpAlreadyRan(frame, MAKE_CELL, i)) { // (likely) MAKE_CELL must have executed already. value = PyCell_GET(value); } // (likely) Otherwise it it is an arg (kind & CO_FAST_LOCAL), // with the initial value set when the frame was created... // (unlikely) ...or it was set to some initial value by // an earlier call to PyFrame_LocalsToFast(). } } } else { assert(value == NULL); } if (value == NULL) { if (PyObject_DelItem(locals, name) != 0) { if (PyErr_ExceptionMatches(PyExc_KeyError)) { PyErr_Clear(); } else { return -1; } } } else { if (PyObject_SetItem(locals, name, value) != 0) { return -1; } } } return 0; } int PyFrame_FastToLocalsWithError(PyFrameObject *f) { assert(!_PyFrame_IsIncomplete(f->f_frame)); if (f == NULL) { PyErr_BadInternalCall(); return -1; } int err = _PyFrame_FastToLocalsWithError(f->f_frame); if (err == 0) { f->f_fast_as_locals = 1; } return err; } void PyFrame_FastToLocals(PyFrameObject *f) { int res; assert(!_PyFrame_IsIncomplete(f->f_frame)); assert(!PyErr_Occurred()); res = PyFrame_FastToLocalsWithError(f); if (res < 0) PyErr_Clear(); } void _PyFrame_LocalsToFast(_PyInterpreterFrame *frame, int clear) { /* Merge locals into fast locals */ PyObject *locals; PyObject **fast; PyObject *error_type, *error_value, *error_traceback; PyCodeObject *co; locals = frame->f_locals; if (locals == NULL) { return; } fast = _PyFrame_GetLocalsArray(frame); co = frame->f_code; bool added_null_checks = false; PyErr_Fetch(&error_type, &error_value, &error_traceback); for (int i = 0; i < co->co_nlocalsplus; i++) { _PyLocals_Kind kind = _PyLocals_GetKind(co->co_localspluskinds, i); /* Same test as in PyFrame_FastToLocals() above. */ if (kind & CO_FAST_FREE && !(co->co_flags & CO_OPTIMIZED)) { continue; } PyObject *name = PyTuple_GET_ITEM(co->co_localsplusnames, i); PyObject *value = PyObject_GetItem(locals, name); /* We only care about NULLs if clear is true. */ if (value == NULL) { PyErr_Clear(); if (!clear) { continue; } } PyObject *oldvalue = fast[i]; if (!added_null_checks && oldvalue != NULL && value == NULL) { add_load_fast_null_checks(co); added_null_checks = true; } PyObject *cell = NULL; if (kind == CO_FAST_FREE) { // The cell was set when the frame was created from // the function's closure. assert(oldvalue != NULL && PyCell_Check(oldvalue)); cell = oldvalue; } else if (kind & CO_FAST_CELL && oldvalue != NULL) { /* Same test as in PyFrame_FastToLocals() above. */ if (PyCell_Check(oldvalue) && _PyFrame_OpAlreadyRan(frame, MAKE_CELL, i)) { // (likely) MAKE_CELL must have executed already. cell = oldvalue; } // (unlikely) Otherwise, it must have been set to some // initial value by an earlier call to PyFrame_LocalsToFast(). } if (cell != NULL) { oldvalue = PyCell_GET(cell); if (value != oldvalue) { Py_XINCREF(value); PyCell_SET(cell, value); Py_XDECREF(oldvalue); } } else if (value != oldvalue) { Py_XINCREF(value); Py_XSETREF(fast[i], value); } Py_XDECREF(value); } PyErr_Restore(error_type, error_value, error_traceback); } void PyFrame_LocalsToFast(PyFrameObject *f, int clear) { assert(!_PyFrame_IsIncomplete(f->f_frame)); if (f && f->f_fast_as_locals && _PyFrame_GetState(f) != FRAME_CLEARED) { _PyFrame_LocalsToFast(f->f_frame, clear); f->f_fast_as_locals = 0; } } int _PyFrame_IsEntryFrame(PyFrameObject *frame) { assert(frame != NULL); assert(!_PyFrame_IsIncomplete(frame->f_frame)); return frame->f_frame->is_entry; } PyCodeObject * PyFrame_GetCode(PyFrameObject *frame) { assert(frame != NULL); assert(!_PyFrame_IsIncomplete(frame->f_frame)); PyCodeObject *code = frame->f_frame->f_code; assert(code != NULL); Py_INCREF(code); return code; } PyFrameObject* PyFrame_GetBack(PyFrameObject *frame) { assert(frame != NULL); assert(!_PyFrame_IsIncomplete(frame->f_frame)); PyFrameObject *back = frame->f_back; if (back == NULL) { _PyInterpreterFrame *prev = frame->f_frame->previous; while (prev && _PyFrame_IsIncomplete(prev)) { prev = prev->previous; } if (prev) { back = _PyFrame_GetFrameObject(prev); } } Py_XINCREF(back); return back; } PyObject* PyFrame_GetLocals(PyFrameObject *frame) { assert(!_PyFrame_IsIncomplete(frame->f_frame)); return frame_getlocals(frame, NULL); } PyObject* PyFrame_GetGlobals(PyFrameObject *frame) { assert(!_PyFrame_IsIncomplete(frame->f_frame)); return frame_getglobals(frame, NULL); } PyObject* PyFrame_GetBuiltins(PyFrameObject *frame) { assert(!_PyFrame_IsIncomplete(frame->f_frame)); return frame_getbuiltins(frame, NULL); } int PyFrame_GetLasti(PyFrameObject *frame) { assert(!_PyFrame_IsIncomplete(frame->f_frame)); int lasti = _PyInterpreterFrame_LASTI(frame->f_frame); if (lasti < 0) { return -1; } return lasti * sizeof(_Py_CODEUNIT); } PyObject * PyFrame_GetGenerator(PyFrameObject *frame) { assert(!_PyFrame_IsIncomplete(frame->f_frame)); if (frame->f_frame->owner != FRAME_OWNED_BY_GENERATOR) { return NULL; } PyGenObject *gen = _PyFrame_GetGenerator(frame->f_frame); return Py_NewRef(gen); } PyObject* _PyEval_BuiltinsFromGlobals(PyThreadState *tstate, PyObject *globals) { PyObject *builtins = PyDict_GetItemWithError(globals, &_Py_ID(__builtins__)); if (builtins) { if (PyModule_Check(builtins)) { builtins = _PyModule_GetDict(builtins); assert(builtins != NULL); } return builtins; } if (PyErr_Occurred()) { return NULL; } return _PyEval_GetBuiltins(tstate); }