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gh-99876: make optimizer maintain the invariant that oparg == 0 for an instruction that does not have an arg #99877

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Merged
merged 7 commits into from
Nov 30, 2022
Merged

gh-99876: make optimizer maintain the invariant that oparg == 0 for an instruction that does not have an arg #99877

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5e4c199
gh-99876: make optimizer maintain the invariant that oparg == 0 for a…
iritkatriel Nov 29, 2022
a9bfc0d
magic number
iritkatriel Nov 29, 2022
dfff7b8
Revert "magic number"
iritkatriel Nov 29, 2022
e911001
fix INSTR_SET_OP1 macro to access arg once
iritkatriel Nov 29, 2022
1f2657c
Merge branch 'main' into instr_set_op
iritkatriel Nov 29, 2022
857db4e
implement Mark's suggestions
iritkatriel Nov 30, 2022
4d046a7
Merge remote-tracking branch 'upstream/main' into instr_set_op
iritkatriel Nov 30, 2022
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64 changes: 41 additions & 23 deletions Python/compile.c
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Original file line number Diff line number Diff line change
Expand Up @@ -171,6 +171,24 @@ struct instr {
struct basicblock_ *i_except; /* target block when exception is raised */
};

/* One arg*/
#define INSTR_SET_OP1(I, OP, ARG) \
do { \
assert(HAS_ARG(OP)); \
struct instr *_instr__ptr_ = (I); \
_instr__ptr_->i_opcode = (OP); \
_instr__ptr_->i_oparg = (ARG); \
} while (0);

/* No args*/
#define INSTR_SET_OP0(I, OP) \
do { \
assert(!HAS_ARG(OP)); \
struct instr *_instr__ptr_ = (I); \
_instr__ptr_->i_opcode = (OP); \
_instr__ptr_->i_oparg = 0; \
} while (0);

typedef struct exceptstack {
struct basicblock_ *handlers[CO_MAXBLOCKS+1];
int depth;
Expand Down Expand Up @@ -218,7 +236,8 @@ instr_size(struct instr *instruction)
{
int opcode = instruction->i_opcode;
assert(!IS_PSEUDO_OPCODE(opcode));
int oparg = HAS_ARG(opcode) ? instruction->i_oparg : 0;
int oparg = instruction->i_oparg;
assert(HAS_ARG(opcode) || oparg == 0);
int extended_args = (0xFFFFFF < oparg) + (0xFFFF < oparg) + (0xFF < oparg);
int caches = _PyOpcode_Caches[opcode];
return extended_args + 1 + caches;
Expand All @@ -229,7 +248,8 @@ write_instr(_Py_CODEUNIT *codestr, struct instr *instruction, int ilen)
{
int opcode = instruction->i_opcode;
assert(!IS_PSEUDO_OPCODE(opcode));
int oparg = HAS_ARG(opcode) ? instruction->i_oparg : 0;
int oparg = instruction->i_oparg;
assert(HAS_ARG(opcode) || oparg == 0);
int caches = _PyOpcode_Caches[opcode];
switch (ilen - caches) {
case 4:
Expand Down Expand Up @@ -7598,7 +7618,7 @@ convert_exception_handlers_to_nops(basicblock *entryblock) {
for (int i = 0; i < b->b_iused; i++) {
struct instr *instr = &b->b_instr[i];
if (is_block_push(instr) || instr->i_opcode == POP_BLOCK) {
instr->i_opcode = NOP;
INSTR_SET_OP0(instr, NOP);
}
}
}
Expand Down Expand Up @@ -8723,7 +8743,7 @@ remove_redundant_jumps(cfg_builder *g) {
}
if (last->i_target == b->b_next) {
assert(b->b_next->b_iused);
last->i_opcode = NOP;
INSTR_SET_OP0(last, NOP);
}
}
}
Expand Down Expand Up @@ -8999,10 +9019,9 @@ fold_tuple_on_constants(PyObject *const_cache,
}
Py_DECREF(newconst);
for (int i = 0; i < n; i++) {
inst[i].i_opcode = NOP;
INSTR_SET_OP0(&inst[i], NOP);
}
inst[n].i_opcode = LOAD_CONST;
inst[n].i_oparg = (int)index;
INSTR_SET_OP1(&inst[n], LOAD_CONST, (int)index);
return 0;
}

Expand Down Expand Up @@ -9099,7 +9118,7 @@ swaptimize(basicblock *block, int *ix)
}
// NOP out any unused instructions:
while (0 <= current) {
instructions[current--].i_opcode = NOP;
INSTR_SET_OP0(&instructions[current--], NOP);
}
PyMem_Free(stack);
*ix += len - 1;
Expand Down Expand Up @@ -9165,7 +9184,7 @@ apply_static_swaps(basicblock *block, int i)
}
}
// Success!
swap->i_opcode = NOP;
INSTR_SET_OP0(swap, NOP);
struct instr temp = block->b_instr[j];
block->b_instr[j] = block->b_instr[k];
block->b_instr[k] = temp;
Expand Down Expand Up @@ -9202,7 +9221,7 @@ optimize_basic_block(PyObject *const_cache, basicblock *bb, PyObject *consts)
assert(PyDict_CheckExact(const_cache));
assert(PyList_CheckExact(consts));
struct instr nop;
nop.i_opcode = NOP;
INSTR_SET_OP0(&nop, NOP);
struct instr *target;
for (int i = 0; i < bb->b_iused; i++) {
struct instr *inst = &bb->b_instr[i];
Expand Down Expand Up @@ -9236,13 +9255,13 @@ optimize_basic_block(PyObject *const_cache, basicblock *bb, PyObject *consts)
if (is_true == -1) {
goto error;
}
inst->i_opcode = NOP;
INSTR_SET_OP0(inst, NOP);
jump_if_true = nextop == POP_JUMP_IF_TRUE;
if (is_true == jump_if_true) {
bb->b_instr[i+1].i_opcode = JUMP;
}
else {
bb->b_instr[i+1].i_opcode = NOP;
INSTR_SET_OP0(&bb->b_instr[i + 1], NOP);
}
break;
case JUMP_IF_FALSE_OR_POP:
Expand All @@ -9261,8 +9280,8 @@ optimize_basic_block(PyObject *const_cache, basicblock *bb, PyObject *consts)
bb->b_instr[i+1].i_opcode = JUMP;
}
else {
inst->i_opcode = NOP;
bb->b_instr[i+1].i_opcode = NOP;
INSTR_SET_OP0(inst, NOP);
INSTR_SET_OP0(&bb->b_instr[i + 1], NOP);
}
break;
case IS_OP:
Expand All @@ -9273,8 +9292,8 @@ optimize_basic_block(PyObject *const_cache, basicblock *bb, PyObject *consts)
int jump_op = i+2 < bb->b_iused ? bb->b_instr[i+2].i_opcode : 0;
if (Py_IsNone(cnt) && (jump_op == POP_JUMP_IF_FALSE || jump_op == POP_JUMP_IF_TRUE)) {
unsigned char nextarg = bb->b_instr[i+1].i_oparg;
inst->i_opcode = NOP;
bb->b_instr[i+1].i_opcode = NOP;
INSTR_SET_OP0(inst, NOP);
INSTR_SET_OP0(&bb->b_instr[i + 1], NOP);
bb->b_instr[i+2].i_opcode = nextarg ^ (jump_op == POP_JUMP_IF_FALSE) ?
POP_JUMP_IF_NOT_NONE : POP_JUMP_IF_NONE;
}
Expand All @@ -9292,12 +9311,12 @@ optimize_basic_block(PyObject *const_cache, basicblock *bb, PyObject *consts)
if (nextop == UNPACK_SEQUENCE && oparg == bb->b_instr[i+1].i_oparg) {
switch(oparg) {
case 1:
inst->i_opcode = NOP;
bb->b_instr[i+1].i_opcode = NOP;
INSTR_SET_OP0(inst, NOP);
INSTR_SET_OP0(&bb->b_instr[i + 1], NOP);
continue;
case 2:
case 3:
inst->i_opcode = NOP;
INSTR_SET_OP0(inst, NOP);
bb->b_instr[i+1].i_opcode = SWAP;
continue;
}
Expand Down Expand Up @@ -9406,7 +9425,7 @@ optimize_basic_block(PyObject *const_cache, basicblock *bb, PyObject *consts)
break;
case SWAP:
if (oparg == 1) {
inst->i_opcode = NOP;
INSTR_SET_OP0(inst, NOP);
break;
}
if (swaptimize(bb, &i)) {
Expand All @@ -9418,8 +9437,7 @@ optimize_basic_block(PyObject *const_cache, basicblock *bb, PyObject *consts)
break;
case PUSH_NULL:
if (nextop == LOAD_GLOBAL && (inst[1].i_opcode & 1) == 0) {
inst->i_opcode = NOP;
inst->i_oparg = 0;
INSTR_SET_OP0(inst, NOP);
inst[1].i_oparg |= 1;
}
break;
Expand Down Expand Up @@ -9448,7 +9466,7 @@ inline_small_exit_blocks(basicblock *bb) {
}
basicblock *target = last->i_target;
if (basicblock_exits_scope(target) && target->b_iused <= MAX_COPY_SIZE) {
last->i_opcode = NOP;
INSTR_SET_OP0(last, NOP);
if (basicblock_append_instructions(bb, target) < 0) {
return -1;
}
Expand Down