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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /tools/perf/util/expr.y
parentInitial commit. (diff)
downloadlinux-upstream.tar.xz
linux-upstream.zip
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r--tools/perf/util/expr.y301
1 files changed, 301 insertions, 0 deletions
diff --git a/tools/perf/util/expr.y b/tools/perf/util/expr.y
new file mode 100644
index 000000000..635e56235
--- /dev/null
+++ b/tools/perf/util/expr.y
@@ -0,0 +1,301 @@
+/* Simple expression parser */
+%{
+#define YYDEBUG 1
+#include <assert.h>
+#include <math.h>
+#include <stdlib.h>
+#include "util/debug.h"
+#define IN_EXPR_Y 1
+#include "expr.h"
+%}
+
+%define api.pure full
+
+%parse-param { double *final_val }
+%parse-param { struct expr_parse_ctx *ctx }
+%parse-param { bool compute_ids }
+%parse-param {void *scanner}
+%lex-param {void* scanner}
+
+%union {
+ double num;
+ char *str;
+ struct ids {
+ /*
+ * When creating ids, holds the working set of event ids. NULL
+ * implies the set is empty.
+ */
+ struct hashmap *ids;
+ /*
+ * The metric value. When not creating ids this is the value
+ * read from a counter, a constant or some computed value. When
+ * creating ids the value is either a constant or BOTTOM. NAN is
+ * used as the special BOTTOM value, representing a "set of all
+ * values" case.
+ */
+ double val;
+ } ids;
+}
+
+%token ID NUMBER MIN MAX IF ELSE LITERAL D_RATIO SOURCE_COUNT EXPR_ERROR
+%left MIN MAX IF
+%left '|'
+%left '^'
+%left '&'
+%left '<' '>'
+%left '-' '+'
+%left '*' '/' '%'
+%left NEG NOT
+%type <num> NUMBER LITERAL
+%type <str> ID
+%destructor { free ($$); } <str>
+%type <ids> expr if_expr
+%destructor { ids__free($$.ids); } <ids>
+
+%{
+static void expr_error(double *final_val __maybe_unused,
+ struct expr_parse_ctx *ctx __maybe_unused,
+ bool compute_ids __maybe_unused,
+ void *scanner,
+ const char *s)
+{
+ pr_debug("%s\n", s);
+}
+
+/*
+ * During compute ids, the special "bottom" value uses NAN to represent the set
+ * of all values. NAN is selected as it isn't a useful constant value.
+ */
+#define BOTTOM NAN
+
+/* During computing ids, does val represent a constant (non-BOTTOM) value? */
+static bool is_const(double val)
+{
+ return isfinite(val);
+}
+
+static struct ids union_expr(struct ids ids1, struct ids ids2)
+{
+ struct ids result = {
+ .val = BOTTOM,
+ .ids = ids__union(ids1.ids, ids2.ids),
+ };
+ return result;
+}
+
+static struct ids handle_id(struct expr_parse_ctx *ctx, char *id,
+ bool compute_ids, bool source_count)
+{
+ struct ids result;
+
+ if (!compute_ids) {
+ /*
+ * Compute the event's value from ID. If the ID isn't known then
+ * it isn't used to compute the formula so set to NAN.
+ */
+ struct expr_id_data *data;
+
+ result.val = NAN;
+ if (expr__resolve_id(ctx, id, &data) == 0) {
+ result.val = source_count
+ ? expr_id_data__source_count(data)
+ : expr_id_data__value(data);
+ }
+ result.ids = NULL;
+ free(id);
+ } else {
+ /*
+ * Set the value to BOTTOM to show that any value is possible
+ * when the event is computed. Create a set of just the ID.
+ */
+ result.val = BOTTOM;
+ result.ids = ids__new();
+ if (!result.ids || ids__insert(result.ids, id)) {
+ pr_err("Error creating IDs for '%s'", id);
+ free(id);
+ }
+ }
+ return result;
+}
+
+/*
+ * If we're not computing ids or $1 and $3 are constants, compute the new
+ * constant value using OP. Its invariant that there are no ids. If computing
+ * ids for non-constants union the set of IDs that must be computed.
+ */
+#define BINARY_LONG_OP(RESULT, OP, LHS, RHS) \
+ if (!compute_ids || (is_const(LHS.val) && is_const(RHS.val))) { \
+ assert(LHS.ids == NULL); \
+ assert(RHS.ids == NULL); \
+ RESULT.val = (long)LHS.val OP (long)RHS.val; \
+ RESULT.ids = NULL; \
+ } else { \
+ RESULT = union_expr(LHS, RHS); \
+ }
+
+#define BINARY_OP(RESULT, OP, LHS, RHS) \
+ if (!compute_ids || (is_const(LHS.val) && is_const(RHS.val))) { \
+ assert(LHS.ids == NULL); \
+ assert(RHS.ids == NULL); \
+ RESULT.val = LHS.val OP RHS.val; \
+ RESULT.ids = NULL; \
+ } else { \
+ RESULT = union_expr(LHS, RHS); \
+ }
+
+%}
+%%
+
+start: if_expr
+{
+ if (compute_ids)
+ ctx->ids = ids__union($1.ids, ctx->ids);
+
+ if (final_val)
+ *final_val = $1.val;
+}
+;
+
+if_expr: expr IF expr ELSE if_expr
+{
+ if (fpclassify($3.val) == FP_ZERO) {
+ /*
+ * The IF expression evaluated to 0 so treat as false, take the
+ * ELSE and discard everything else.
+ */
+ $$.val = $5.val;
+ $$.ids = $5.ids;
+ ids__free($1.ids);
+ ids__free($3.ids);
+ } else if (!compute_ids || is_const($3.val)) {
+ /*
+ * If ids aren't computed then treat the expression as true. If
+ * ids are being computed and the IF expr is a non-zero
+ * constant, then also evaluate the true case.
+ */
+ $$.val = $1.val;
+ $$.ids = $1.ids;
+ ids__free($3.ids);
+ ids__free($5.ids);
+ } else if ($1.val == $5.val) {
+ /*
+ * LHS == RHS, so both are an identical constant. No need to
+ * evaluate any events.
+ */
+ $$.val = $1.val;
+ $$.ids = NULL;
+ ids__free($1.ids);
+ ids__free($3.ids);
+ ids__free($5.ids);
+ } else {
+ /*
+ * Value is either the LHS or RHS and we need the IF expression
+ * to compute it.
+ */
+ $$ = union_expr($1, union_expr($3, $5));
+ }
+}
+| expr
+;
+
+expr: NUMBER
+{
+ $$.val = $1;
+ $$.ids = NULL;
+}
+| ID { $$ = handle_id(ctx, $1, compute_ids, /*source_count=*/false); }
+| SOURCE_COUNT '(' ID ')' { $$ = handle_id(ctx, $3, compute_ids, /*source_count=*/true); }
+| expr '|' expr { BINARY_LONG_OP($$, |, $1, $3); }
+| expr '&' expr { BINARY_LONG_OP($$, &, $1, $3); }
+| expr '^' expr { BINARY_LONG_OP($$, ^, $1, $3); }
+| expr '<' expr { BINARY_OP($$, <, $1, $3); }
+| expr '>' expr { BINARY_OP($$, >, $1, $3); }
+| expr '+' expr { BINARY_OP($$, +, $1, $3); }
+| expr '-' expr { BINARY_OP($$, -, $1, $3); }
+| expr '*' expr { BINARY_OP($$, *, $1, $3); }
+| expr '/' expr
+{
+ if (fpclassify($3.val) == FP_ZERO) {
+ pr_debug("division by zero\n");
+ YYABORT;
+ } else if (!compute_ids || (is_const($1.val) && is_const($3.val))) {
+ assert($1.ids == NULL);
+ assert($3.ids == NULL);
+ $$.val = $1.val / $3.val;
+ $$.ids = NULL;
+ } else {
+ /* LHS and/or RHS need computing from event IDs so union. */
+ $$ = union_expr($1, $3);
+ }
+}
+| expr '%' expr
+{
+ if (fpclassify($3.val) == FP_ZERO) {
+ pr_debug("division by zero\n");
+ YYABORT;
+ } else if (!compute_ids || (is_const($1.val) && is_const($3.val))) {
+ assert($1.ids == NULL);
+ assert($3.ids == NULL);
+ $$.val = (long)$1.val % (long)$3.val;
+ $$.ids = NULL;
+ } else {
+ /* LHS and/or RHS need computing from event IDs so union. */
+ $$ = union_expr($1, $3);
+ }
+}
+| D_RATIO '(' expr ',' expr ')'
+{
+ if (fpclassify($5.val) == FP_ZERO) {
+ /*
+ * Division by constant zero always yields zero and no events
+ * are necessary.
+ */
+ assert($5.ids == NULL);
+ $$.val = 0.0;
+ $$.ids = NULL;
+ ids__free($3.ids);
+ } else if (!compute_ids || (is_const($3.val) && is_const($5.val))) {
+ assert($3.ids == NULL);
+ assert($5.ids == NULL);
+ $$.val = $3.val / $5.val;
+ $$.ids = NULL;
+ } else {
+ /* LHS and/or RHS need computing from event IDs so union. */
+ $$ = union_expr($3, $5);
+ }
+}
+| '-' expr %prec NEG
+{
+ $$.val = -$2.val;
+ $$.ids = $2.ids;
+}
+| '(' if_expr ')'
+{
+ $$ = $2;
+}
+| MIN '(' expr ',' expr ')'
+{
+ if (!compute_ids) {
+ $$.val = $3.val < $5.val ? $3.val : $5.val;
+ $$.ids = NULL;
+ } else {
+ $$ = union_expr($3, $5);
+ }
+}
+| MAX '(' expr ',' expr ')'
+{
+ if (!compute_ids) {
+ $$.val = $3.val > $5.val ? $3.val : $5.val;
+ $$.ids = NULL;
+ } else {
+ $$ = union_expr($3, $5);
+ }
+}
+| LITERAL
+{
+ $$.val = $1;
+ $$.ids = NULL;
+}
+;
+
+%%