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gh-117288: Allocate fewer label IDs in _PyCfg_ToInstructionSequence #117290

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merged 2 commits into from
Mar 27, 2024
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gh-117288: Allocate fewer label IDs in _PyCfg_ToInstructionSequence #117290

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44f1df1
gh-117288: Allocate fewer label IDs in _PyCfg_ToInstructionSequence
iritkatriel Mar 27, 2024
87d4960
fix sanitizer warning
iritkatriel Mar 27, 2024
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1 change: 1 addition & 0 deletions Include/internal/pycore_compile.h
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Original file line number Diff line number Diff line change
Expand Up @@ -66,6 +66,7 @@ int _PyCompile_InstructionSequence_UseLabel(_PyCompile_InstructionSequence *seq,
int _PyCompile_InstructionSequence_Addop(_PyCompile_InstructionSequence *seq,
int opcode, int oparg,
_PyCompilerSrcLocation loc);
int _PyCompile_InstructionSequence_ApplyLabelMap(_PyCompile_InstructionSequence *seq);

typedef struct {
PyObject *u_name;
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3 changes: 3 additions & 0 deletions Python/assemble.c
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Expand Up @@ -736,6 +736,9 @@ _PyAssemble_MakeCodeObject(_PyCompile_CodeUnitMetadata *umd, PyObject *const_cac
int nlocalsplus, int code_flags, PyObject *filename)
{

if (_PyCompile_InstructionSequence_ApplyLabelMap(instrs) < 0) {
return NULL;
}
if (resolve_unconditional_jumps(instrs) < 0) {
return NULL;
}
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34 changes: 30 additions & 4 deletions Python/compile.c
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Expand Up @@ -235,6 +235,28 @@ _PyCompile_InstructionSequence_UseLabel(instr_sequence *seq, int lbl)
return SUCCESS;
}

int
_PyCompile_InstructionSequence_ApplyLabelMap(instr_sequence *instrs)
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Maybe just _PyCompile_ApplyLabelMap?
The InstructionSequence seems redundant given the argument is an instruction sequence.
You choose.

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I'm planning to move the instruction-sequence data structure implementation out of compile.c, so it will probably end up being _PyInstructionSequence_ApplyLabelMap.

{
/* Replace labels by offsets in the code */
for (int i=0; i < instrs->s_used; i++) {
instruction *instr = &instrs->s_instrs[i];
if (HAS_TARGET(instr->i_opcode)) {
assert(instr->i_oparg < instrs->s_labelmap_size);
instr->i_oparg = instrs->s_labelmap[instr->i_oparg];
}
_PyCompile_ExceptHandlerInfo *hi = &instr->i_except_handler_info;
if (hi->h_label >= 0) {
assert(hi->h_label < instrs->s_labelmap_size);
hi->h_label = instrs->s_labelmap[hi->h_label];
}
}
/* Clear label map so it's never used again */
PyMem_Free(instrs->s_labelmap);
instrs->s_labelmap = NULL;
instrs->s_labelmap_size = 0;
return SUCCESS;
}

#define MAX_OPCODE 511

Expand Down Expand Up @@ -7772,11 +7794,8 @@ instr_sequence_to_instructions(instr_sequence *seq)
for (int i = 0; i < seq->s_used; i++) {
instruction *instr = &seq->s_instrs[i];
location loc = instr->i_loc;
int arg = HAS_TARGET(instr->i_opcode) ?
seq->s_labelmap[instr->i_oparg] : instr->i_oparg;

PyObject *inst_tuple = Py_BuildValue(
"(iiiiii)", instr->i_opcode, arg,
"(iiiiii)", instr->i_opcode, instr->i_oparg,
loc.lineno, loc.end_lineno,
loc.col_offset, loc.end_col_offset);
if (inst_tuple == NULL) {
Expand All @@ -7803,6 +7822,9 @@ cfg_to_instructions(cfg_builder *g)
if (_PyCfg_ToInstructionSequence(g, &seq) < 0) {
return NULL;
}
if (_PyCompile_InstructionSequence_ApplyLabelMap(&seq) < 0) {
return NULL;
}
PyObject *res = instr_sequence_to_instructions(&seq);
instr_sequence_fini(&seq);
return res;
Expand Down Expand Up @@ -7974,6 +7996,10 @@ _PyCompile_CodeGen(PyObject *ast, PyObject *filename, PyCompilerFlags *pflags,
goto finally;
}

if (_PyCompile_InstructionSequence_ApplyLabelMap(INSTR_SEQUENCE(c)) < 0) {
return NULL;
}

PyObject *insts = instr_sequence_to_instructions(INSTR_SEQUENCE(c));
if (insts == NULL) {
goto finally;
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5 changes: 3 additions & 2 deletions Python/flowgraph.c
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Expand Up @@ -2717,13 +2717,14 @@ _PyCfg_ToInstructionSequence(cfg_builder *g, _PyCompile_InstructionSequence *seq
int lbl = 0;
for (basicblock *b = g->g_entryblock; b != NULL; b = b->b_next) {
b->b_label = (jump_target_label){lbl};
lbl += b->b_iused;
lbl += 1;
}
for (basicblock *b = g->g_entryblock; b != NULL; b = b->b_next) {
RETURN_IF_ERROR(_PyCompile_InstructionSequence_UseLabel(seq, b->b_label.id));
for (int i = 0; i < b->b_iused; i++) {
cfg_instr *instr = &b->b_instr[i];
if (OPCODE_HAS_JUMP(instr->i_opcode) || is_block_push(instr)) {
if (HAS_TARGET(instr->i_opcode)) {
/* Set oparg to the label id (it will later be mapped to an offset) */
instr->i_oparg = instr->i_target->b_label.id;
}
RETURN_IF_ERROR(
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