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cdata: Move .end and (optional) .endid_offset into a separata array.
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These fields are only used at the end of input, and moving them into a
different struct will make the per-state data accessed during DFA
execution more compact.
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@silentbicycle
silentbicycle committed Oct 30, 2024
1 parent adf2f2c commit 55306b1
Showing 1 changed file with 47 additions and 33 deletions.
80 changes: 47 additions & 33 deletions src/libfsm/print/cdata.c
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Original file line number Diff line number Diff line change
Expand Up @@ -174,14 +174,10 @@ generate_struct_definition(FILE *f, const struct cdata_config *config, bool comm
"\ttypedef %s %s_cdata_state;\n",
id_type_str(config->t_state_id), prefix);

/* TODO: move .end and .endid_offset into a separate table, they aren't accessed
* until the end of input, so this should slightly reduce cache misses.
* Do this once there's baseline timing info. */
fprintf(f,
"\tstruct %s_cdata_dfa {\n"
"\t\t%s_cdata_state start;\n"
"\t\tstruct %s_cdata_state {\n"
"\t\t\tbool end; /* is this an end state? */\n"
"\n", prefix, prefix, prefix);

if (comments) {
Expand Down Expand Up @@ -210,9 +206,6 @@ generate_struct_definition(FILE *f, const struct cdata_config *config, bool comm
}
fprintf(f, "\t\t\t%s dst_table_offset;\n", id_type_str(config->t_dst_state_offset));

if (has_endids) {
fprintf(f, "\t\t\t%s endid_offset;\n", id_type_str(config->t_endid_offset));
}
if (has_eager_outputs) {
fprintf(f, "\t\t\t%s eager_output_offset;\n", id_type_str(config->t_eager_output_offset));
}
Expand All @@ -221,6 +214,21 @@ generate_struct_definition(FILE *f, const struct cdata_config *config, bool comm
"\t\t} states[%zd];\n"
"\n", config->state_count);

/* .end could be a single uint64_t bitset */
if (comments) {
fprintf(f, "\t\t/* State-associated info only checked at end of input */\n");
}
fprintf(f,
"\t\tstruct %s_state_end_info {\n"
"\t\t\tbool end; /* is this an end state? */\n", prefix);
if (has_endids) {
fprintf(f, "\t\t\t%s endid_offset; /* or %zu for NONE */\n",
id_type_str(config->t_endid_offset), config->endid_buf.used);
}
fprintf(f,
"\t\t} state_end_info[%zd];\n"
"\n", config->state_count);

if (comments) {
fprintf(f,
"\t\t/* Destination states for each edge group in each state,\n"
Expand Down Expand Up @@ -272,8 +280,6 @@ generate_data(FILE *f, const struct cdata_config *config,
const struct ir_state *s = &ir->states[s_i];
const struct state_info *si = &config->state_info[s_i];

const bool is_end = s->isend;
const bool has_endids = si->endid != STATE_OFFSET_NONE;
const bool has_eager_outputs = si->eager_output != STATE_OFFSET_NONE;

fprintf(f, "\t\t\t[%zd] = {%s\n", s_i, s_i == config->start ? " /* start */" : "");
Expand Down Expand Up @@ -315,7 +321,6 @@ generate_data(FILE *f, const struct cdata_config *config,

const size_t state_NONE = config->state_count;
const size_t dst_table_NONE = config->dst_buf.used;
const size_t endid_NONE = config->endid_buf.used;
const size_t eager_output_NONE = config->eager_output_buf.used;

if (si->default_dst == STATE_OFFSET_NONE) {
Expand All @@ -331,52 +336,61 @@ generate_data(FILE *f, const struct cdata_config *config,
fprintf(f, "\t\t\t\t.default_dst = %zu,\n", si->default_dst);
}

fprintf(f, "\t\t\t\t.end = %d,\n", is_end);

if (si->dst == STATE_OFFSET_NONE) { /* no non-default outgoing edges */
fprintf(f, "\t\t\t\t.dst_table_offset = %zd, /* NONE */\n", dst_table_NONE);
} else {
fprintf(f, "\t\t\t\t.dst_table_offset = %zd,\n", si->dst);
}

/* Only include these if any state uses endids/eager_outputs, and
* if this state doesn't then use the end of the array as NONE. */
if (config->endid_buf.used > 0) {
if (has_endids) {
if (config->eager_output_buf.used > 0) {
if (has_eager_outputs) {
if (comments) {
fprintf(f, "\t\t\t\t/* endids:");
for (size_t i = 0; i < s->endids.count; i++) {
fprintf(f, "\t\t\t\t/* eager_outputs:");
for (size_t i = 0; i < s->eager_outputs->count; i++) {
if (i > 0 && (i & 15) == 0) {
fprintf(f, "\n\t\t\t\t *");
}
fprintf(f, " %u", s->endids.ids[i]);
fprintf(f, " %u", s->eager_outputs->ids[i]);
}
fprintf(f, " */\n");
}
fprintf(f, "\t\t\t\t.endid_offset = %zd,\n", si->endid);
fprintf(f, "\t\t\t\t.eager_output_offset = %zd,\n", si->eager_output);
} else {
fprintf(f, "\t\t\t\t.endid_offset = %zd, /* NONE */\n", endid_NONE);
fprintf(f, "\t\t\t\t.eager_output_offset = %zd, /* NONE */\n", eager_output_NONE);
}
}

if (config->eager_output_buf.used > 0) {
if (has_eager_outputs) {
fprintf(f, "\t\t\t},\n");
}
fprintf(f, "\t\t},\n");

fprintf(f, "\t\t.state_end_info = {\n");
for (size_t s_i = 0; s_i < ir->n; s_i++) {
const size_t endid_NONE = config->endid_buf.used;
const struct ir_state *s = &ir->states[s_i];
const struct state_info *si = &config->state_info[s_i];
fprintf(f, "\t\t\t[%zu] = {\n", s_i);
fprintf(f, "\t\t\t\t.end = %d,\n", s->isend);

/* Only include these if any state uses endids/eager_outputs, and
* if this state doesn't then use the end of the array as NONE. */
if (config->endid_buf.used > 0) {
if (si->endid != STATE_OFFSET_NONE) {
if (comments) {
fprintf(f, "\t\t\t\t/* eager_outputs:");
for (size_t i = 0; i < s->eager_outputs->count; i++) {
fprintf(f, "\t\t\t\t/* endids:");
for (size_t i = 0; i < s->endids.count; i++) {
if (i > 0 && (i & 15) == 0) {
fprintf(f, "\n\t\t\t\t *");
}
fprintf(f, " %u", s->eager_outputs->ids[i]);
fprintf(f, " %u", s->endids.ids[i]);
}
fprintf(f, " */\n");
}
fprintf(f, "\t\t\t\t.eager_output_offset = %zd,\n", si->eager_output);
fprintf(f, "\t\t\t\t.endid_offset = %zd,\n", si->endid);
} else {
fprintf(f, "\t\t\t\t.eager_output_offset = %zd, /* NONE */\n", eager_output_NONE);
fprintf(f, "\t\t\t\t.endid_offset = %zd, /* NONE */\n", endid_NONE);
}
}

fprintf(f, "\t\t\t},\n");
}
fprintf(f, "\t\t},\n");
Expand Down Expand Up @@ -574,8 +588,8 @@ generate_interpreter(FILE *f, const struct cdata_config *config, const struct fs
/* At the end of the input, check if the current state is an end.
* If not, there's no match. */
fprintf(f,
"\tconst struct %s_cdata_state *state = &%s_dfa_data.states[cur_state];\n"
"\tif (!state->end) { return 0; /* no match */ }\n", prefix, prefix);
"\tconst struct %s_state_end_info *state_end = &%s_dfa_data.state_end_info[cur_state];\n"
"\tif (!state_end->end) { return 0; /* no match */ }\n", prefix, prefix);

/* Set the passed-in reference to the endids, if any. */
if (has_endids) {
Expand All @@ -586,8 +600,8 @@ generate_interpreter(FILE *f, const struct cdata_config *config, const struct fs
* by the first lower value. endid_table[] has an extra 0 appended
* as a terminator for the last set. */
fprintf(f,
"\tif (state->endid_offset < %s_ENDID_TABLE_COUNT) {\n"
"\t\t%s *endid_scan = &%s_dfa_data.endid_table[state->endid_offset];\n"
"\tif (state_end->endid_offset < %s_ENDID_TABLE_COUNT) {\n"
"\t\t%s *endid_scan = &%s_dfa_data.endid_table[state_end->endid_offset];\n"
"\t\tconst %s *endid_base = endid_scan;\n"
"\t\tsize_t endid_count = 0;\n"
"\t\tuint64_t cur, next;\n"
Expand Down

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