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GH-93516: Store offset of first traceable instruction in code object #93769

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Merged
merged 4 commits into from
Jun 14, 2022
+54 −53
Merged

GH-93516: Store offset of first traceable instruction in code object #93769

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cc44d3b
Store offset of first traceable instruction to avoid having to recomp…
markshannon Jun 13, 2022
4af267e
Hardcode RESUME opcode in deepfreeze, to break dependency on exact ve…
markshannon Jun 13, 2022
ea8bea2
Handle empty code objects, and other invalid code, gracefully.
markshannon Jun 13, 2022
a3ad259
Check bounds before data
markshannon Jun 14, 2022
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1 change: 1 addition & 0 deletions Include/cpython/code.h
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Original file line number Diff line number Diff line change
Expand Up @@ -89,6 +89,7 @@ typedef uint16_t _Py_CODEUNIT;
PyObject *co_linetable; /* bytes object that holds location info */ \
PyObject *co_weakreflist; /* to support weakrefs to code objects */ \
void *_co_code; /* cached co_code object/attribute */ \
int _co_firsttraceable; /* index of first traceable instruction */ \
/* Scratch space for extra data relating to the code object. \
Type is a void* to keep the format private in codeobject.c to force \
people to go through the proper APIs. */ \
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2 changes: 1 addition & 1 deletion Lib/opcode.py
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Original file line number Diff line number Diff line change
Expand Up @@ -177,7 +177,7 @@ def jabs_op(name, op):
hasfree.append(148)
def_op('COPY_FREE_VARS', 149)
def_op('YIELD_VALUE', 150)
def_op('RESUME', 151)
def_op('RESUME', 151) # This must be kept in sync with deepfreeze.py
def_op('MATCH_CLASS', 152)

def_op('FORMAT_VALUE', 155)
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2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/Core and Builtins/2022-06-13-13-55-34.gh-issue-93516.HILrDl.rst
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@@ -0,0 +1,2 @@
Store offset of first traceable instruction in code object to avoid having
to recompute it for each instruction when tracing.
6 changes: 6 additions & 0 deletions Objects/codeobject.c
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Original file line number Diff line number Diff line change
Expand Up @@ -339,6 +339,12 @@ init_code(PyCodeObject *co, struct _PyCodeConstructor *con)
co->co_warmup = QUICKENING_INITIAL_WARMUP_VALUE;
memcpy(_PyCode_CODE(co), PyBytes_AS_STRING(con->code),
PyBytes_GET_SIZE(con->code));
int entry_point = 0;
while (entry_point < Py_SIZE(co) &&
_Py_OPCODE(_PyCode_CODE(co)[entry_point]) != RESUME) {
entry_point++;
}
co->_co_firsttraceable = entry_point;
}

static int
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89 changes: 37 additions & 52 deletions Python/ceval.c
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Expand Up @@ -5568,57 +5568,47 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
case DO_TRACING:
#endif
{
if (tstate->tracing == 0) {
if (tstate->tracing == 0 &&
INSTR_OFFSET() >= frame->f_code->_co_firsttraceable
) {
int instr_prev = _PyInterpreterFrame_LASTI(frame);
frame->prev_instr = next_instr;
TRACING_NEXTOPARG();
switch(opcode) {
case COPY_FREE_VARS:
case MAKE_CELL:
case RETURN_GENERATOR:
/* Frame not fully initialized */
break;
case RESUME:
if (oparg < 2) {
CHECK_EVAL_BREAKER();
}
/* Call tracing */
TRACE_FUNCTION_ENTRY();
DTRACE_FUNCTION_ENTRY();
break;
case POP_TOP:
if (_Py_OPCODE(next_instr[-1]) == RETURN_GENERATOR) {
/* Frame not fully initialized */
break;
}
/* fall through */
default:
/* line-by-line tracing support */
if (PyDTrace_LINE_ENABLED()) {
maybe_dtrace_line(frame, &tstate->trace_info, instr_prev);
}

if (cframe.use_tracing &&
tstate->c_tracefunc != NULL && !tstate->tracing) {
int err;
/* see maybe_call_line_trace()
for expository comments */
_PyFrame_SetStackPointer(frame, stack_pointer);

err = maybe_call_line_trace(tstate->c_tracefunc,
tstate->c_traceobj,
tstate, frame, instr_prev);
if (err) {
/* trace function raised an exception */
next_instr++;
goto error;
}
/* Reload possibly changed frame fields */
next_instr = frame->prev_instr;
if (opcode == RESUME) {
if (oparg < 2) {
CHECK_EVAL_BREAKER();
}
/* Call tracing */
TRACE_FUNCTION_ENTRY();
DTRACE_FUNCTION_ENTRY();
}
else {
/* line-by-line tracing support */
if (PyDTrace_LINE_ENABLED()) {
maybe_dtrace_line(frame, &tstate->trace_info, instr_prev);
}

stack_pointer = _PyFrame_GetStackPointer(frame);
frame->stacktop = -1;
if (cframe.use_tracing &&
tstate->c_tracefunc != NULL && !tstate->tracing) {
int err;
/* see maybe_call_line_trace()
for expository comments */
_PyFrame_SetStackPointer(frame, stack_pointer);

err = maybe_call_line_trace(tstate->c_tracefunc,
tstate->c_traceobj,
tstate, frame, instr_prev);
if (err) {
/* trace function raised an exception */
next_instr++;
goto error;
}
/* Reload possibly changed frame fields */
next_instr = frame->prev_instr;

stack_pointer = _PyFrame_GetStackPointer(frame);
frame->stacktop = -1;
}
}
}
TRACING_NEXTOPARG();
Expand Down Expand Up @@ -6855,13 +6845,8 @@ maybe_call_line_trace(Py_tracefunc func, PyObject *obj,
then call the trace function if we're tracing source lines.
*/
initialize_trace_info(&tstate->trace_info, frame);
int entry_point = 0;
_Py_CODEUNIT *code = _PyCode_CODE(frame->f_code);
while (_PyOpcode_Deopt[_Py_OPCODE(code[entry_point])] != RESUME) {
entry_point++;
}
int lastline;
if (instr_prev <= entry_point) {
if (instr_prev <= frame->f_code->_co_firsttraceable) {
lastline = -1;
}
else {
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7 changes: 7 additions & 0 deletions Tools/scripts/deepfreeze.py
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Original file line number Diff line number Diff line change
Expand Up @@ -20,6 +20,9 @@
verbose = False
identifiers, strings = get_identifiers_and_strings()

# This must be kept in sync with opcode.py
RESUME = 151

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Can't this be opcode.opmap["RESUME"]?

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No, that would introduce a dependency on the latest opcode.py which would mean you cannot run deepfreeze.py with e.g. Python 3.10. On Windows and for cross compilations we need to be able to do that. (Windows doesn't have a separate bootstrap Python because it would near-doubel build times.)

We started with this (see #93771).

def isprintable(b: bytes) -> bool:
return all(0x20 <= c < 0x7f for c in b)

Expand Down Expand Up @@ -267,6 +270,10 @@ def generate_code(self, name: str, code: types.CodeType) -> str:
self.write(f".co_qualname = {co_qualname},")
self.write(f".co_linetable = {co_linetable},")
self.write(f".co_code_adaptive = {co_code_adaptive},")
for i, op in enumerate(code.co_code[::2]):
if op == RESUME:
self.write(f"._co_firsttraceable = {i},")
break
name_as_code = f"(PyCodeObject *)&{name}"
self.deallocs.append(f"_PyStaticCode_Dealloc({name_as_code});")
self.interns.append(f"_PyStaticCode_InternStrings({name_as_code})")
Expand Down