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Avoid unnecessary stack entries in query analysis

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When descending into a hidden child rule, the current stack entry
can be reused if it is currently at the end of its rule.

This fixes a test failure when analyzing a Ruby query. The
failure was introduced due to some changes to the Ruby grammar.
This optimization allows us to impose a _smaller_ limit on
the stack size, which should make query analysis faster and
more memory-efficient.
This commit is contained in:
Max Brunsfeld 2021-11-19 11:04:36 -08:00
parent 52b4b65adc
commit 1fe0420f0f
1 changed files with 29 additions and 16 deletions
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45
lib/src/query.c
View file

@ -13,7 +13,7 @@
#define MAX_STEP_CAPTURE_COUNT 3
#define MAX_STATE_PREDECESSOR_COUNT 100
#define MAX_ANALYSIS_STATE_DEPTH 12
#define MAX_ANALYSIS_STATE_DEPTH 8
#define MAX_NEGATED_FIELD_COUNT 8
/*
@ -1123,9 +1123,10 @@ static bool ts_query__analyze_patterns(TSQuery *self, unsigned *error_offset) {
// Create a new state that has advanced past this hypothetical subtree.
AnalysisState next_state = *state;
analysis_state__top(&next_state)->child_index++;
analysis_state__top(&next_state)->parse_state = successor.state;
if (node->done) analysis_state__top(&next_state)->done = true;
AnalysisStateEntry *next_state_top = analysis_state__top(&next_state);
next_state_top->child_index++;
next_state_top->parse_state = successor.state;
if (node->done) next_state_top->done = true;
// Determine if this hypothetical child node would match the current step
// of the query pattern.
@ -1146,20 +1147,31 @@ static bool ts_query__analyze_patterns(TSQuery *self, unsigned *error_offset) {
) does_match = false;
}
// If this is a hidden child, then push a new entry to the stack, in order to
// walk through the children of this child.
// If this child is hidden, then descend into it and walk through its children.
// If the top entry of the stack is at the end of its rule, then that entry can
// be replaced. Otherwise, push a new entry onto the stack.
else if (sym >= self->language->token_count) {
if (next_state.depth + 1 >= MAX_ANALYSIS_STATE_DEPTH) {
did_exceed_max_depth = true;
continue;
if (!next_state_top->done) {
if (next_state.depth + 1 >= MAX_ANALYSIS_STATE_DEPTH) {
#ifdef DEBUG_ANALYZE_QUERY
printf("Exceeded depth limit for state %u\n", j);
#endif
did_exceed_max_depth = true;
continue;
}
next_state.depth++;
next_state_top = analysis_state__top(&next_state);
}
next_state.depth++;
analysis_state__top(&next_state)->parse_state = parse_state;
analysis_state__top(&next_state)->child_index = 0;
analysis_state__top(&next_state)->parent_symbol = sym;
analysis_state__top(&next_state)->field_id = field_id;
analysis_state__top(&next_state)->done = false;
*next_state_top = (AnalysisStateEntry) {
.parse_state = parse_state,
.parent_symbol = sym,
.child_index = 0,
.field_id = field_id,
.done = false,
};
if (analysis_state__recursion_depth(&next_state) > recursion_depth_limit) {
array_insert_sorted_with(&deeper_states, analysis_state__compare, next_state);
@ -1168,8 +1180,9 @@ static bool ts_query__analyze_patterns(TSQuery *self, unsigned *error_offset) {
}
// Pop from the stack when this state reached the end of its current syntax node.
while (next_state.depth > 0 && analysis_state__top(&next_state)->done) {
while (next_state.depth > 0 && next_state_top->done) {
next_state.depth--;
next_state_top = analysis_state__top(&next_state);
}
// If this hypothetical child did match the current step of the query pattern,