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bpo-44840: Compiler: Move duplication of exit blocks with no line numbers to after CFG optimization. (GH-27656) (#27673)

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(cherry picked from commit b854557b49)
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Mark Shannon 2021-08-09 10:54:48 +01:00 • committed by GitHub
parent 7d6a0fe5b8
commit 762ef85f44
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6 changed files with 3907 additions and 3873 deletions
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40
Python/compile.c
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@ -862,7 +862,7 @@ compiler_copy_block(struct compiler *c, basicblock *block)
* a block can only have one fallthrough predecessor.
*/
assert(block->b_nofallthrough);
basicblock *result = compiler_next_block(c);
basicblock *result = compiler_new_block(c);
if (result == NULL) {
return NULL;
}
@ -6980,8 +6980,9 @@ normalize_basic_block(basicblock *bb);
static int
optimize_cfg(struct compiler *c, struct assembler *a, PyObject *consts);
/* Duplicates exit BBs, so that line numbers can be propagated to them */
static int
ensure_exits_have_lineno(struct compiler *c);
duplicate_exits_without_lineno(struct compiler *c);
static int
extend_block(basicblock *bb);
@ -7035,10 +7036,10 @@ guarantee_lineno_for_exits(struct assembler *a, int firstlineno) {
}
struct instr *last = &b->b_instr[b->b_iused-1];
if (last->i_lineno < 0) {
if (last->i_opcode == RETURN_VALUE)
{
if (last->i_opcode == RETURN_VALUE) {
for (int i = 0; i < b->b_iused; i++) {
assert(b->b_instr[i].i_lineno < 0);
b->b_instr[i].i_lineno = lineno;
}
}
@ -7049,6 +7050,9 @@ guarantee_lineno_for_exits(struct assembler *a, int firstlineno) {
}
}
static void
propagate_line_numbers(struct assembler *a);
static PyCodeObject *
assemble(struct compiler *c, int addNone)
{
@ -7081,10 +7085,6 @@ assemble(struct compiler *c, int addNone)
}
}
if (ensure_exits_have_lineno(c)) {
return NULL;
}
nblocks = 0;
entryblock = NULL;
for (b = c->u->u_blocks; b != NULL; b = b->b_list) {
@ -7118,8 +7118,11 @@ assemble(struct compiler *c, int addNone)
if (optimize_cfg(c, &a, consts)) {
goto error;
}
if (duplicate_exits_without_lineno(c)) {
return NULL;
}
propagate_line_numbers(&a);
guarantee_lineno_for_exits(&a, c->u->u_firstlineno);
/* Can't modify the bytecode after computing jump offsets. */
assemble_jump_offsets(&a, c);
@ -7691,7 +7694,7 @@ eliminate_empty_basic_blocks(basicblock *entry) {
* but has no impact on the generated line number events.
*/
static void
propogate_line_numbers(struct assembler *a) {
propagate_line_numbers(struct assembler *a) {
for (basicblock *b = a->a_entry; b != NULL; b = b->b_next) {
if (b->b_iused == 0) {
continue;
@ -7748,6 +7751,11 @@ optimize_cfg(struct compiler *c, struct assembler *a, PyObject *consts)
clean_basic_block(b, -1);
assert(b->b_predecessors == 0);
}
for (basicblock *b = c->u->u_blocks; b != NULL; b = b->b_list) {
if (extend_block(b)) {
return -1;
}
}
if (mark_reachable(a)) {
return -1;
}
@ -7792,7 +7800,6 @@ optimize_cfg(struct compiler *c, struct assembler *a, PyObject *consts)
if (maybe_empty_blocks) {
eliminate_empty_basic_blocks(a->a_entry);
}
propogate_line_numbers(a);
return 0;
}
@ -7811,7 +7818,7 @@ is_exit_without_lineno(basicblock *b) {
* copy the line number from the sole predecessor block.
*/
static int
ensure_exits_have_lineno(struct compiler *c)
duplicate_exits_without_lineno(struct compiler *c)
{
basicblock *entry = NULL;
/* Copy all exit blocks without line number that are targets of a jump.
@ -7826,21 +7833,22 @@ ensure_exits_have_lineno(struct compiler *c)
continue;
}
basicblock *target = b->b_instr[b->b_iused-1].i_target;
if (is_exit_without_lineno(target)) {
if (is_exit_without_lineno(target) && target->b_predecessors > 1) {
basicblock *new_target = compiler_copy_block(c, target);
if (new_target == NULL) {
return -1;
}
new_target->b_instr[0].i_lineno = b->b_instr[b->b_iused-1].i_lineno;
b->b_instr[b->b_iused-1].i_target = new_target;
target->b_predecessors--;
new_target->b_predecessors = 1;
new_target->b_next = target->b_next;
target->b_next = new_target;
}
}
entry = b;
}
assert(entry != NULL);
if (is_exit_without_lineno(entry)) {
entry->b_instr[0].i_lineno = c->u->u_firstlineno;
}
/* Eliminate empty blocks */
for (basicblock *b = c->u->u_blocks; b != NULL; b = b->b_list) {
while (b->b_next && b->b_next->b_iused == 0) {