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GH-113710: Add a peephole optimization pass. #114487

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Merged
markshannon merged 4 commits into from
Jan 24, 2024
Merged

GH-113710: Add a peephole optimization pass. #114487

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9d22a48
Convert _LOAD_CONST to inline versions during tier 2 optimization
markshannon Jan 17, 2024
f15fede
Remove debug code
markshannon Jan 17, 2024
42374f4
Perform a couple of peephole optimizations for tier 2.
markshannon Jan 17, 2024
c423aac
Remove blank line
markshannon Jan 18, 2024
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7 changes: 4 additions & 3 deletions Include/internal/pycore_uop_ids.h
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2 changes: 2 additions & 0 deletions Include/internal/pycore_uop_metadata.h
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Original file line number Diff line number Diff line change
Expand Up @@ -202,6 +202,7 @@ const uint16_t _PyUop_Flags[MAX_UOP_ID+1] = {
[_SAVE_RETURN_OFFSET] = HAS_ARG_FLAG,
[_EXIT_TRACE] = HAS_DEOPT_FLAG,
[_CHECK_VALIDITY] = HAS_DEOPT_FLAG,
[_LOAD_CONST_INLINE] = 0,
[_LOAD_CONST_INLINE_BORROW] = 0,
[_INTERNAL_INCREMENT_OPT_COUNTER] = 0,
};
Expand Down Expand Up @@ -329,6 +330,7 @@ const char *const _PyOpcode_uop_name[MAX_UOP_ID+1] = {
[_LOAD_ATTR_WITH_HINT] = "_LOAD_ATTR_WITH_HINT",
[_LOAD_BUILD_CLASS] = "_LOAD_BUILD_CLASS",
[_LOAD_CONST] = "_LOAD_CONST",
[_LOAD_CONST_INLINE] = "_LOAD_CONST_INLINE",
[_LOAD_CONST_INLINE_BORROW] = "_LOAD_CONST_INLINE_BORROW",
[_LOAD_DEREF] = "_LOAD_DEREF",
[_LOAD_FAST] = "_LOAD_FAST",
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4 changes: 4 additions & 0 deletions Python/bytecodes.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4070,6 +4070,10 @@ dummy_func(
DEOPT_IF(!current_executor->vm_data.valid);
}

op(_LOAD_CONST_INLINE, (ptr/4 -- value)) {
value = Py_NewRef(ptr);
}

op(_LOAD_CONST_INLINE_BORROW, (ptr/4 -- value)) {
value = ptr;
}
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9 changes: 9 additions & 0 deletions Python/executor_cases.c.h
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6 changes: 6 additions & 0 deletions Python/optimizer.c
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Original file line number Diff line number Diff line change
Expand Up @@ -588,6 +588,9 @@ translate_bytecode_to_trace(
ADD_TO_TRACE(uop, oparg, operand, target);
if (uop == _POP_FRAME) {
TRACE_STACK_POP();
/* Set the operand to the code object returned to,
* to assist optimization passes */
trace[trace_length-1].operand = (uintptr_t)code;
DPRINTF(2,
"Returning to %s (%s:%d) at byte offset %d\n",
PyUnicode_AsUTF8(code->co_qualname),
Expand Down Expand Up @@ -629,6 +632,9 @@ translate_bytecode_to_trace(
instr += _PyOpcode_Caches[_PyOpcode_Deopt[opcode]] + 1;
TRACE_STACK_PUSH();
_Py_BloomFilter_Add(dependencies, new_code);
/* Set the operand to the callee's code object,
* to assist optimization passes */
trace[trace_length-1].operand = (uintptr_t)new_code;
code = new_code;
instr = _PyCode_CODE(code);
DPRINTF(2,
Expand Down
34 changes: 34 additions & 0 deletions Python/optimizer_analysis.c
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,39 @@
#include <stddef.h>
#include "pycore_optimizer.h"

static void
peephole_opt(PyCodeObject *co, _PyUOpInstruction *buffer, int buffer_size)
{
for (int pc = 0; pc < buffer_size; pc++) {
int opcode = buffer[pc].opcode;
switch(opcode) {
case _LOAD_CONST: {
assert(co != NULL);
PyObject *val = PyTuple_GET_ITEM(co->co_consts, buffer[pc].oparg);
buffer[pc].opcode = _Py_IsImmortal(val) ? _LOAD_CONST_INLINE_BORROW : _LOAD_CONST_INLINE;
buffer[pc].operand = (uintptr_t)val;
break;
}
case _CHECK_PEP_523:
{
/* Setting the eval frame function invalidates
* all executors, so no need to check dynamically */
if (_PyInterpreterState_GET()->eval_frame == NULL) {
buffer[pc].opcode = _NOP;
}
break;
}
case _PUSH_FRAME:
case _POP_FRAME:
co = (PyCodeObject *)buffer[pc].operand;
break;
case _JUMP_TO_TOP:
case _EXIT_TRACE:
return;
}
}
}

static void
remove_unneeded_uops(_PyUOpInstruction *buffer, int buffer_size)
{
Expand Down Expand Up @@ -59,6 +92,7 @@ _Py_uop_analyze_and_optimize(
int curr_stacklen
)
{
peephole_opt(co, buffer, buffer_size);
remove_unneeded_uops(buffer, buffer_size);
return 0;
}
10 changes: 7 additions & 3 deletions Python/pystate.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2367,11 +2367,15 @@ _PyInterpreterState_SetEvalFrameFunc(PyInterpreterState *interp,
_PyFrameEvalFunction eval_frame)
{
if (eval_frame == _PyEval_EvalFrameDefault) {
interp->eval_frame = NULL;
eval_frame = NULL;
}
else {
interp->eval_frame = eval_frame;
if (eval_frame == interp->eval_frame) {
return;
}
if (eval_frame != NULL) {
_Py_Executors_InvalidateAll(interp);
}
interp->eval_frame = eval_frame;
}


Expand Down