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1/* Simple expression parser */
2%{
3#define YYDEBUG 1
4#include <assert.h>
5#include <math.h>
6#include <stdlib.h>
7#include "util/debug.h"
8#define IN_EXPR_Y 1
9#include "expr.h"
10%}
11
12%define api.pure full
13
14%parse-param { double *final_val }
15%parse-param { struct expr_parse_ctx *ctx }
16%parse-param { bool compute_ids }
17%parse-param {void *scanner}
18%lex-param {void* scanner}
19
20%union {
21 double num;
22 char *str;
23 struct ids {
24 /*
25 * When creating ids, holds the working set of event ids. NULL
26 * implies the set is empty.
27 */
28 struct hashmap *ids;
29 /*
30 * The metric value. When not creating ids this is the value
31 * read from a counter, a constant or some computed value. When
32 * creating ids the value is either a constant or BOTTOM. NAN is
33 * used as the special BOTTOM value, representing a "set of all
34 * values" case.
35 */
36 double val;
37 } ids;
38}
39
40%token ID NUMBER MIN MAX IF ELSE LITERAL D_RATIO SOURCE_COUNT EXPR_ERROR
41%left MIN MAX IF
42%left '|'
43%left '^'
44%left '&'
45%left '<' '>'
46%left '-' '+'
47%left '*' '/' '%'
48%left NEG NOT
49%type <num> NUMBER LITERAL
50%type <str> ID
51%destructor { free ($$); } <str>
52%type <ids> expr if_expr
53%destructor { ids__free($$.ids); } <ids>
54
55%{
56static void expr_error(double *final_val __maybe_unused,
57 struct expr_parse_ctx *ctx __maybe_unused,
58 bool compute_ids __maybe_unused,
59 void *scanner,
60 const char *s)
61{
62 pr_debug("%s\n", s);
63}
64
65/*
66 * During compute ids, the special "bottom" value uses NAN to represent the set
67 * of all values. NAN is selected as it isn't a useful constant value.
68 */
69#define BOTTOM NAN
70
71/* During computing ids, does val represent a constant (non-BOTTOM) value? */
72static bool is_const(double val)
73{
74 return isfinite(val);
75}
76
77static struct ids union_expr(struct ids ids1, struct ids ids2)
78{
79 struct ids result = {
80 .val = BOTTOM,
81 .ids = ids__union(ids1.ids, ids2.ids),
82 };
83 return result;
84}
85
86static struct ids handle_id(struct expr_parse_ctx *ctx, char *id,
87 bool compute_ids, bool source_count)
88{
89 struct ids result;
90
91 if (!compute_ids) {
92 /*
93 * Compute the event's value from ID. If the ID isn't known then
94 * it isn't used to compute the formula so set to NAN.
95 */
96 struct expr_id_data *data;
97
98 result.val = NAN;
99 if (expr__resolve_id(ctx, id, &data) == 0) {
100 result.val = source_count
101 ? expr_id_data__source_count(data)
102 : expr_id_data__value(data);
103 }
104 result.ids = NULL;
105 free(id);
106 } else {
107 /*
108 * Set the value to BOTTOM to show that any value is possible
109 * when the event is computed. Create a set of just the ID.
110 */
111 result.val = BOTTOM;
112 result.ids = ids__new();
113 if (!result.ids || ids__insert(result.ids, id)) {
114 pr_err("Error creating IDs for '%s'", id);
115 free(id);
116 }
117 }
118 return result;
119}
120
121/*
122 * If we're not computing ids or $1 and $3 are constants, compute the new
123 * constant value using OP. Its invariant that there are no ids. If computing
124 * ids for non-constants union the set of IDs that must be computed.
125 */
126#define BINARY_LONG_OP(RESULT, OP, LHS, RHS) \
127 if (!compute_ids || (is_const(LHS.val) && is_const(RHS.val))) { \
128 assert(LHS.ids == NULL); \
129 assert(RHS.ids == NULL); \
130 RESULT.val = (long)LHS.val OP (long)RHS.val; \
131 RESULT.ids = NULL; \
132 } else { \
133 RESULT = union_expr(LHS, RHS); \
134 }
135
136#define BINARY_OP(RESULT, OP, LHS, RHS) \
137 if (!compute_ids || (is_const(LHS.val) && is_const(RHS.val))) { \
138 assert(LHS.ids == NULL); \
139 assert(RHS.ids == NULL); \
140 RESULT.val = LHS.val OP RHS.val; \
141 RESULT.ids = NULL; \
142 } else { \
143 RESULT = union_expr(LHS, RHS); \
144 }
145
146%}
147%%
148
149start: if_expr
150{
151 if (compute_ids)
152 ctx->ids = ids__union($1.ids, ctx->ids);
153
154 if (final_val)
155 *final_val = $1.val;
156}
157;
158
159if_expr: expr IF expr ELSE if_expr
160{
161 if (fpclassify($3.val) == FP_ZERO) {
162 /*
163 * The IF expression evaluated to 0 so treat as false, take the
164 * ELSE and discard everything else.
165 */
166 $$.val = $5.val;
167 $$.ids = $5.ids;
168 ids__free($1.ids);
169 ids__free($3.ids);
170 } else if (!compute_ids || is_const($3.val)) {
171 /*
172 * If ids aren't computed then treat the expression as true. If
173 * ids are being computed and the IF expr is a non-zero
174 * constant, then also evaluate the true case.
175 */
176 $$.val = $1.val;
177 $$.ids = $1.ids;
178 ids__free($3.ids);
179 ids__free($5.ids);
180 } else if ($1.val == $5.val) {
181 /*
182 * LHS == RHS, so both are an identical constant. No need to
183 * evaluate any events.
184 */
185 $$.val = $1.val;
186 $$.ids = NULL;
187 ids__free($1.ids);
188 ids__free($3.ids);
189 ids__free($5.ids);
190 } else {
191 /*
192 * Value is either the LHS or RHS and we need the IF expression
193 * to compute it.
194 */
195 $$ = union_expr($1, union_expr($3, $5));
196 }
197}
198| expr
199;
200
201expr: NUMBER
202{
203 $$.val = $1;
204 $$.ids = NULL;
205}
206| ID { $$ = handle_id(ctx, $1, compute_ids, /*source_count=*/false); }
207| SOURCE_COUNT '(' ID ')' { $$ = handle_id(ctx, $3, compute_ids, /*source_count=*/true); }
208| expr '|' expr { BINARY_LONG_OP($$, |, $1, $3); }
209| expr '&' expr { BINARY_LONG_OP($$, &, $1, $3); }
210| expr '^' expr { BINARY_LONG_OP($$, ^, $1, $3); }
211| expr '<' expr { BINARY_OP($$, <, $1, $3); }
212| expr '>' expr { BINARY_OP($$, >, $1, $3); }
213| expr '+' expr { BINARY_OP($$, +, $1, $3); }
214| expr '-' expr { BINARY_OP($$, -, $1, $3); }
215| expr '*' expr { BINARY_OP($$, *, $1, $3); }
216| expr '/' expr
217{
218 if (fpclassify($3.val) == FP_ZERO) {
219 pr_debug("division by zero\n");
220 YYABORT;
221 } else if (!compute_ids || (is_const($1.val) && is_const($3.val))) {
222 assert($1.ids == NULL);
223 assert($3.ids == NULL);
224 $$.val = $1.val / $3.val;
225 $$.ids = NULL;
226 } else {
227 /* LHS and/or RHS need computing from event IDs so union. */
228 $$ = union_expr($1, $3);
229 }
230}
231| expr '%' expr
232{
233 if (fpclassify($3.val) == FP_ZERO) {
234 pr_debug("division by zero\n");
235 YYABORT;
236 } else if (!compute_ids || (is_const($1.val) && is_const($3.val))) {
237 assert($1.ids == NULL);
238 assert($3.ids == NULL);
239 $$.val = (long)$1.val % (long)$3.val;
240 $$.ids = NULL;
241 } else {
242 /* LHS and/or RHS need computing from event IDs so union. */
243 $$ = union_expr($1, $3);
244 }
245}
246| D_RATIO '(' expr ',' expr ')'
247{
248 if (fpclassify($5.val) == FP_ZERO) {
249 /*
250 * Division by constant zero always yields zero and no events
251 * are necessary.
252 */
253 assert($5.ids == NULL);
254 $$.val = 0.0;
255 $$.ids = NULL;
256 ids__free($3.ids);
257 } else if (!compute_ids || (is_const($3.val) && is_const($5.val))) {
258 assert($3.ids == NULL);
259 assert($5.ids == NULL);
260 $$.val = $3.val / $5.val;
261 $$.ids = NULL;
262 } else {
263 /* LHS and/or RHS need computing from event IDs so union. */
264 $$ = union_expr($3, $5);
265 }
266}
267| '-' expr %prec NEG
268{
269 $$.val = -$2.val;
270 $$.ids = $2.ids;
271}
272| '(' if_expr ')'
273{
274 $$ = $2;
275}
276| MIN '(' expr ',' expr ')'
277{
278 if (!compute_ids) {
279 $$.val = $3.val < $5.val ? $3.val : $5.val;
280 $$.ids = NULL;
281 } else {
282 $$ = union_expr($3, $5);
283 }
284}
285| MAX '(' expr ',' expr ')'
286{
287 if (!compute_ids) {
288 $$.val = $3.val > $5.val ? $3.val : $5.val;
289 $$.ids = NULL;
290 } else {
291 $$ = union_expr($3, $5);
292 }
293}
294| LITERAL
295{
296 $$.val = $1;
297 $$.ids = NULL;
298}
299;
300
301%%
1/* Simple expression parser */
2%{
3#ifndef NDEBUG
4#define YYDEBUG 1
5#endif
6#include <assert.h>
7#include <math.h>
8#include <stdlib.h>
9#include "util/debug.h"
10#define IN_EXPR_Y 1
11#include "expr.h"
12#include "expr-bison.h"
13int expr_lex(YYSTYPE * yylval_param , void *yyscanner);
14%}
15
16%define api.pure full
17
18%parse-param { double *final_val }
19%parse-param { struct expr_parse_ctx *ctx }
20%parse-param { bool compute_ids }
21%parse-param {void *scanner}
22%lex-param {void* scanner}
23
24%union {
25 double num;
26 char *str;
27 struct ids {
28 /*
29 * When creating ids, holds the working set of event ids. NULL
30 * implies the set is empty.
31 */
32 struct hashmap *ids;
33 /*
34 * The metric value. When not creating ids this is the value
35 * read from a counter, a constant or some computed value. When
36 * creating ids the value is either a constant or BOTTOM. NAN is
37 * used as the special BOTTOM value, representing a "set of all
38 * values" case.
39 */
40 double val;
41 } ids;
42}
43
44%token ID NUMBER MIN MAX IF ELSE LITERAL D_RATIO SOURCE_COUNT HAS_EVENT STRCMP_CPUID_STR EXPR_ERROR
45%left MIN MAX IF
46%left '|'
47%left '^'
48%left '&'
49%left '<' '>'
50%left '-' '+'
51%left '*' '/' '%'
52%left NEG NOT
53%type <num> NUMBER LITERAL
54%type <str> ID
55%destructor { free ($$); } <str>
56%type <ids> expr if_expr
57%destructor { ids__free($$.ids); } <ids>
58
59%{
60static void expr_error(double *final_val __maybe_unused,
61 struct expr_parse_ctx *ctx __maybe_unused,
62 bool compute_ids __maybe_unused,
63 void *scanner __maybe_unused,
64 const char *s)
65{
66 pr_debug("%s\n", s);
67}
68
69/*
70 * During compute ids, the special "bottom" value uses NAN to represent the set
71 * of all values. NAN is selected as it isn't a useful constant value.
72 */
73#define BOTTOM NAN
74
75/* During computing ids, does val represent a constant (non-BOTTOM) value? */
76static bool is_const(double val)
77{
78 return isfinite(val);
79}
80
81static struct ids union_expr(struct ids ids1, struct ids ids2)
82{
83 struct ids result = {
84 .val = BOTTOM,
85 .ids = ids__union(ids1.ids, ids2.ids),
86 };
87 return result;
88}
89
90static struct ids handle_id(struct expr_parse_ctx *ctx, char *id,
91 bool compute_ids, bool source_count)
92{
93 struct ids result;
94
95 if (!compute_ids) {
96 /*
97 * Compute the event's value from ID. If the ID isn't known then
98 * it isn't used to compute the formula so set to NAN.
99 */
100 struct expr_id_data *data;
101
102 result.val = NAN;
103 if (expr__resolve_id(ctx, id, &data) == 0) {
104 result.val = source_count
105 ? expr_id_data__source_count(data)
106 : expr_id_data__value(data);
107 }
108 result.ids = NULL;
109 free(id);
110 } else {
111 /*
112 * Set the value to BOTTOM to show that any value is possible
113 * when the event is computed. Create a set of just the ID.
114 */
115 result.val = BOTTOM;
116 result.ids = ids__new();
117 if (!result.ids || ids__insert(result.ids, id)) {
118 pr_err("Error creating IDs for '%s'", id);
119 free(id);
120 }
121 }
122 return result;
123}
124
125/*
126 * If we're not computing ids or $1 and $3 are constants, compute the new
127 * constant value using OP. Its invariant that there are no ids. If computing
128 * ids for non-constants union the set of IDs that must be computed.
129 */
130#define BINARY_OP(RESULT, OP, LHS, RHS) \
131 if (!compute_ids || (is_const(LHS.val) && is_const(RHS.val))) { \
132 assert(LHS.ids == NULL); \
133 assert(RHS.ids == NULL); \
134 if (isnan(LHS.val) || isnan(RHS.val)) { \
135 RESULT.val = NAN; \
136 } else { \
137 RESULT.val = LHS.val OP RHS.val; \
138 } \
139 RESULT.ids = NULL; \
140 } else { \
141 RESULT = union_expr(LHS, RHS); \
142 }
143
144%}
145%%
146
147start: if_expr
148{
149 if (compute_ids)
150 ctx->ids = ids__union($1.ids, ctx->ids);
151
152 if (final_val)
153 *final_val = $1.val;
154}
155;
156
157if_expr: expr IF expr ELSE if_expr
158{
159 if (fpclassify($3.val) == FP_ZERO) {
160 /*
161 * The IF expression evaluated to 0 so treat as false, take the
162 * ELSE and discard everything else.
163 */
164 $$.val = $5.val;
165 $$.ids = $5.ids;
166 ids__free($1.ids);
167 ids__free($3.ids);
168 } else if (!compute_ids || is_const($3.val)) {
169 /*
170 * If ids aren't computed then treat the expression as true. If
171 * ids are being computed and the IF expr is a non-zero
172 * constant, then also evaluate the true case.
173 */
174 $$.val = $1.val;
175 $$.ids = $1.ids;
176 ids__free($3.ids);
177 ids__free($5.ids);
178 } else if ($1.val == $5.val) {
179 /*
180 * LHS == RHS, so both are an identical constant. No need to
181 * evaluate any events.
182 */
183 $$.val = $1.val;
184 $$.ids = NULL;
185 ids__free($1.ids);
186 ids__free($3.ids);
187 ids__free($5.ids);
188 } else {
189 /*
190 * Value is either the LHS or RHS and we need the IF expression
191 * to compute it.
192 */
193 $$ = union_expr($1, union_expr($3, $5));
194 }
195}
196| expr
197;
198
199expr: NUMBER
200{
201 $$.val = $1;
202 $$.ids = NULL;
203}
204| ID { $$ = handle_id(ctx, $1, compute_ids, /*source_count=*/false); }
205| SOURCE_COUNT '(' ID ')' { $$ = handle_id(ctx, $3, compute_ids, /*source_count=*/true); }
206| HAS_EVENT '(' ID ')'
207{
208 $$.val = expr__has_event(ctx, compute_ids, $3);
209 $$.ids = NULL;
210 free($3);
211}
212| STRCMP_CPUID_STR '(' ID ')'
213{
214 $$.val = expr__strcmp_cpuid_str(ctx, compute_ids, $3);
215 $$.ids = NULL;
216 free($3);
217}
218| expr '|' expr
219{
220 if (is_const($1.val) && is_const($3.val)) {
221 assert($1.ids == NULL);
222 assert($3.ids == NULL);
223 $$.ids = NULL;
224 $$.val = (fpclassify($1.val) == FP_ZERO && fpclassify($3.val) == FP_ZERO) ? 0 : 1;
225 } else if (is_const($1.val)) {
226 assert($1.ids == NULL);
227 if (fpclassify($1.val) == FP_ZERO) {
228 $$ = $3;
229 } else {
230 $$.val = 1;
231 $$.ids = NULL;
232 ids__free($3.ids);
233 }
234 } else if (is_const($3.val)) {
235 assert($3.ids == NULL);
236 if (fpclassify($3.val) == FP_ZERO) {
237 $$ = $1;
238 } else {
239 $$.val = 1;
240 $$.ids = NULL;
241 ids__free($1.ids);
242 }
243 } else {
244 $$ = union_expr($1, $3);
245 }
246}
247| expr '&' expr
248{
249 if (is_const($1.val) && is_const($3.val)) {
250 assert($1.ids == NULL);
251 assert($3.ids == NULL);
252 $$.val = (fpclassify($1.val) != FP_ZERO && fpclassify($3.val) != FP_ZERO) ? 1 : 0;
253 $$.ids = NULL;
254 } else if (is_const($1.val)) {
255 assert($1.ids == NULL);
256 if (fpclassify($1.val) != FP_ZERO) {
257 $$ = $3;
258 } else {
259 $$.val = 0;
260 $$.ids = NULL;
261 ids__free($3.ids);
262 }
263 } else if (is_const($3.val)) {
264 assert($3.ids == NULL);
265 if (fpclassify($3.val) != FP_ZERO) {
266 $$ = $1;
267 } else {
268 $$.val = 0;
269 $$.ids = NULL;
270 ids__free($1.ids);
271 }
272 } else {
273 $$ = union_expr($1, $3);
274 }
275}
276| expr '^' expr
277{
278 if (is_const($1.val) && is_const($3.val)) {
279 assert($1.ids == NULL);
280 assert($3.ids == NULL);
281 $$.val = (fpclassify($1.val) == FP_ZERO) != (fpclassify($3.val) == FP_ZERO) ? 1 : 0;
282 $$.ids = NULL;
283 } else {
284 $$ = union_expr($1, $3);
285 }
286}
287| expr '<' expr { BINARY_OP($$, <, $1, $3); }
288| expr '>' expr { BINARY_OP($$, >, $1, $3); }
289| expr '+' expr { BINARY_OP($$, +, $1, $3); }
290| expr '-' expr { BINARY_OP($$, -, $1, $3); }
291| expr '*' expr { BINARY_OP($$, *, $1, $3); }
292| expr '/' expr
293{
294 if (fpclassify($3.val) == FP_ZERO) {
295 pr_debug("division by zero\n");
296 assert($3.ids == NULL);
297 if (compute_ids)
298 ids__free($1.ids);
299 $$.val = NAN;
300 $$.ids = NULL;
301 } else if (!compute_ids || (is_const($1.val) && is_const($3.val))) {
302 assert($1.ids == NULL);
303 assert($3.ids == NULL);
304 $$.val = $1.val / $3.val;
305 $$.ids = NULL;
306 } else {
307 /* LHS and/or RHS need computing from event IDs so union. */
308 $$ = union_expr($1, $3);
309 }
310}
311| expr '%' expr
312{
313 if (fpclassify($3.val) == FP_ZERO) {
314 pr_debug("division by zero\n");
315 YYABORT;
316 } else if (!compute_ids || (is_const($1.val) && is_const($3.val))) {
317 assert($1.ids == NULL);
318 assert($3.ids == NULL);
319 $$.val = (long)$1.val % (long)$3.val;
320 $$.ids = NULL;
321 } else {
322 /* LHS and/or RHS need computing from event IDs so union. */
323 $$ = union_expr($1, $3);
324 }
325}
326| D_RATIO '(' expr ',' expr ')'
327{
328 if (fpclassify($5.val) == FP_ZERO) {
329 /*
330 * Division by constant zero always yields zero and no events
331 * are necessary.
332 */
333 assert($5.ids == NULL);
334 $$.val = 0.0;
335 $$.ids = NULL;
336 ids__free($3.ids);
337 } else if (!compute_ids || (is_const($3.val) && is_const($5.val))) {
338 assert($3.ids == NULL);
339 assert($5.ids == NULL);
340 $$.val = $3.val / $5.val;
341 $$.ids = NULL;
342 } else {
343 /* LHS and/or RHS need computing from event IDs so union. */
344 $$ = union_expr($3, $5);
345 }
346}
347| '-' expr %prec NEG
348{
349 $$.val = -$2.val;
350 $$.ids = $2.ids;
351}
352| '(' if_expr ')'
353{
354 $$ = $2;
355}
356| MIN '(' expr ',' expr ')'
357{
358 if (!compute_ids) {
359 $$.val = $3.val < $5.val ? $3.val : $5.val;
360 $$.ids = NULL;
361 } else {
362 $$ = union_expr($3, $5);
363 }
364}
365| MAX '(' expr ',' expr ')'
366{
367 if (!compute_ids) {
368 $$.val = $3.val > $5.val ? $3.val : $5.val;
369 $$.ids = NULL;
370 } else {
371 $$ = union_expr($3, $5);
372 }
373}
374| LITERAL
375{
376 $$.val = $1;
377 $$.ids = NULL;
378}
379;
380
381%%