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gh-87092: in compiler, move the detection of exception handlers before the CFG optimization stage (GH-96935)

This commit is contained in:
Irit Katriel 2022-09-20 13:14:07 +01:00 committed by GitHub
parent fc05107af9
commit 98e785d364
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 32 additions and 16 deletions
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48
Python/compile.c
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@ -258,10 +258,8 @@ typedef struct basicblock_ {
int b_iused;
/* length of instruction array (b_instr) */
int b_ialloc;
/* Number of predecssors that a block has. */
/* Number of predecessors that a block has. */
int b_predecessors;
/* Number of predecssors that a block has as an exception handler. */
int b_except_predecessors;
/* depth of stack upon entry of block, computed by stackdepth() */
int b_startdepth;
/* instruction offset for block, computed by assemble_jump_offsets() */
@ -270,6 +268,8 @@ typedef struct basicblock_ {
unsigned b_preserve_lasti : 1;
/* Used by compiler passes to mark whether they have visited a basic block. */
unsigned b_visited : 1;
/* b_except_handler is used by the cold-detection algorithm to mark exception targets */
unsigned b_except_handler : 1;
/* b_cold is true if this block is not perf critical (like an exception handler) */
unsigned b_cold : 1;
/* b_warm is used by the cold-detection algorithm to mark blocks which are definitely not cold */
@ -7296,6 +7296,25 @@ error:
return -1;
}
static int
mark_except_handlers(basicblock *entryblock) {
#ifndef NDEBUG
for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
assert(!b->b_except_handler);
}
#endif
for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
for (int i=0; i < b->b_iused; i++) {
struct instr *instr = &b->b_instr[i];
if (is_block_push(instr)) {
instr->i_target->b_except_handler = 1;
}
}
}
return 0;
}
static int
mark_warm(basicblock *entryblock) {
basicblock **stack = make_cfg_traversal_stack(entryblock);
@ -7308,7 +7327,7 @@ mark_warm(basicblock *entryblock) {
entryblock->b_visited = 1;
while (sp > stack) {
basicblock *b = *(--sp);
assert(!b->b_except_predecessors);
assert(!b->b_except_handler);
b->b_warm = 1;
basicblock *next = b->b_next;
if (next && BB_HAS_FALLTHROUGH(b) && !next->b_visited) {
@ -7343,8 +7362,7 @@ mark_cold(basicblock *entryblock) {
basicblock **sp = stack;
for (basicblock *b = entryblock; b != NULL; b = b->b_next) {
if (b->b_except_predecessors) {
assert(b->b_except_predecessors == b->b_predecessors);
if (b->b_except_handler) {
assert(!b->b_warm);
*sp++ = b;
b->b_visited = 1;
@ -8257,8 +8275,8 @@ static void
dump_basicblock(const basicblock *b)
{
const char *b_return = basicblock_returns(b) ? "return " : "";
fprintf(stderr, "%d: [%d %d %d %p] used: %d, depth: %d, offset: %d %s\n",
b->b_label, b->b_cold, b->b_warm, BB_NO_FALLTHROUGH(b), b, b->b_iused,
fprintf(stderr, "%d: [EH=%d CLD=%d WRM=%d NO_FT=%d %p] used: %d, depth: %d, offset: %d %s\n",
b->b_label, b->b_except_handler, b->b_cold, b->b_warm, BB_NO_FALLTHROUGH(b), b, b->b_iused,
b->b_startdepth, b->b_offset, b_return);
if (b->b_instr) {
int i;
@ -8616,6 +8634,12 @@ assemble(struct compiler *c, int addNone)
if (calculate_jump_targets(g->g_entryblock)) {
goto error;
}
if (mark_except_handlers(g->g_entryblock) < 0) {
goto error;
}
if (label_exception_targets(g->g_entryblock)) {
goto error;
}
if (optimize_cfg(g, consts, c->c_const_cache)) {
goto error;
}
@ -8634,9 +8658,6 @@ assemble(struct compiler *c, int addNone)
}
/* TO DO -- For 3.12, make sure that `maxdepth <= MAX_ALLOWED_STACK_USE` */
if (label_exception_targets(g->g_entryblock)) {
goto error;
}
convert_exception_handlers_to_nops(g->g_entryblock);
if (push_cold_blocks_to_end(g, code_flags) < 0) {
@ -9353,11 +9374,6 @@ mark_reachable(basicblock *entryblock) {
*sp++ = target;
}
target->b_predecessors++;
if (is_block_push(instr)) {
target->b_except_predecessors++;
}
assert(target->b_except_predecessors == 0 ||
target->b_except_predecessors == target->b_predecessors);
}
}
}