lkml.org 
[lkml]   [2017]   [Mar]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH 07/13] perf, tools: Add a simple expression parser for JSON
    Em Tue, Mar 21, 2017 at 04:14:23PM -0300, Arnaldo Carvalho de Melo escreveu:
    > Em Mon, Mar 20, 2017 at 01:17:05PM -0700, Andi Kleen escreveu:
    > > From: Andi Kleen <ak@linux.intel.com>
    > >
    > > Add a simple expression parser good enough to parse JSON relation
    > > expressions. The parser is implemented using bison.
    >
    > Renaming 'foo_expr' to 'foo_json_expr', as 'expr' is _way_ too
    > generic...

    I retract that, it is used with JSON, but isn't strictly tied to it,
    keeping as is, nevermind.

    - Arnaldo

    > - Arnaldo
    >
    > > This is just intended as an simple parser for internal usage
    > > in the event lists, not the beginning of a "perf scripting language"
    > >
    > > v2: Use expr__ prefix instead of expr_
    > > Support multiple free variables for parser
    > > Signed-off-by: Andi Kleen <ak@linux.intel.com>
    > > ---
    > > tools/perf/tests/Build | 1 +
    > > tools/perf/tests/builtin-test.c | 4 +
    > > tools/perf/tests/expr.c | 55 +++++++++++++
    > > tools/perf/tests/tests.h | 1 +
    > > tools/perf/util/Build | 5 ++
    > > tools/perf/util/expr.h | 25 ++++++
    > > tools/perf/util/expr.y | 173 ++++++++++++++++++++++++++++++++++++++++
    > > 7 files changed, 264 insertions(+)
    > > create mode 100644 tools/perf/tests/expr.c
    > > create mode 100644 tools/perf/util/expr.h
    > > create mode 100644 tools/perf/util/expr.y
    > >
    > > diff --git a/tools/perf/tests/Build b/tools/perf/tests/Build
    > > index 1cb3d9b540e9..af58ebc243ef 100644
    > > --- a/tools/perf/tests/Build
    > > +++ b/tools/perf/tests/Build
    > > @@ -38,6 +38,7 @@ perf-y += cpumap.o
    > > perf-y += stat.o
    > > perf-y += event_update.o
    > > perf-y += event-times.o
    > > +perf-y += expr.o
    > > perf-y += backward-ring-buffer.o
    > > perf-y += sdt.o
    > > perf-y += is_printable_array.o
    > > diff --git a/tools/perf/tests/builtin-test.c b/tools/perf/tests/builtin-test.c
    > > index 83c4669cbc5b..86822969e8a8 100644
    > > --- a/tools/perf/tests/builtin-test.c
    > > +++ b/tools/perf/tests/builtin-test.c
    > > @@ -44,6 +44,10 @@ static struct test generic_tests[] = {
    > > .func = test__parse_events,
    > > },
    > > {
    > > + .desc = "Simple expression parser",
    > > + .func = test__expr,
    > > + },
    > > + {
    > > .desc = "PERF_RECORD_* events & perf_sample fields",
    > > .func = test__PERF_RECORD,
    > > },
    > > diff --git a/tools/perf/tests/expr.c b/tools/perf/tests/expr.c
    > > new file mode 100644
    > > index 000000000000..554695c06c5b
    > > --- /dev/null
    > > +++ b/tools/perf/tests/expr.c
    > > @@ -0,0 +1,55 @@
    > > +#include "util/debug.h"
    > > +#include "util/expr.h"
    > > +#include "tests.h"
    > > +
    > > +static int test(struct parse_ctx *ctx, const char *e, double val2)
    > > +{
    > > + double val;
    > > +
    > > + if (expr__parse(&val, ctx, &e))
    > > + TEST_ASSERT_VAL("parse test failed", 0);
    > > + TEST_ASSERT_VAL("unexpected value", val == val2);
    > > + return 0;
    > > +}
    > > +
    > > +int test__expr(int subtest __maybe_unused)
    > > +{
    > > + const char *p;
    > > + const char **other;
    > > + double val;
    > > + int ret;
    > > + struct parse_ctx ctx;
    > > + int num_other;
    > > +
    > > + expr__ctx_init(&ctx);
    > > + expr__add_id(&ctx, "FOO", 1);
    > > + expr__add_id(&ctx, "BAR", 2);
    > > +
    > > + ret = test(&ctx, "1+1", 2);
    > > + ret |= test(&ctx, "FOO+BAR", 3);
    > > + ret |= test(&ctx, "(BAR/2)%2", 1);
    > > + ret |= test(&ctx, "1 - -4", 5);
    > > + ret |= test(&ctx, "(FOO-1)*2 + (BAR/2)%2 - -4", 5);
    > > +
    > > + if (ret)
    > > + return ret;
    > > +
    > > + p = "FOO/0";
    > > + ret = expr__parse(&val, &ctx, &p);
    > > + TEST_ASSERT_VAL("division by zero", ret == 1);
    > > +
    > > + p = "BAR/";
    > > + ret = expr__parse(&val, &ctx, &p);
    > > + TEST_ASSERT_VAL("missing operand", ret == 1);
    > > +
    > > + TEST_ASSERT_VAL("find other",
    > > + expr__find_other("FOO + BAR + BAZ + BOZO", "FOO", &other, &num_other) == 0);
    > > + TEST_ASSERT_VAL("find other", num_other == 3);
    > > + TEST_ASSERT_VAL("find other", !strcmp(other[0], "BAR"));
    > > + TEST_ASSERT_VAL("find other", !strcmp(other[1], "BAZ"));
    > > + TEST_ASSERT_VAL("find other", !strcmp(other[2], "BOZO"));
    > > + TEST_ASSERT_VAL("find other", other[3] == NULL);
    > > + free((void *)other);
    > > +
    > > + return 0;
    > > +}
    > > diff --git a/tools/perf/tests/tests.h b/tools/perf/tests/tests.h
    > > index 1fa9b9d83aa5..631859629403 100644
    > > --- a/tools/perf/tests/tests.h
    > > +++ b/tools/perf/tests/tests.h
    > > @@ -62,6 +62,7 @@ int test__sample_parsing(int subtest);
    > > int test__keep_tracking(int subtest);
    > > int test__parse_no_sample_id_all(int subtest);
    > > int test__dwarf_unwind(int subtest);
    > > +int test__expr(int subtest);
    > > int test__hists_filter(int subtest);
    > > int test__mmap_thread_lookup(int subtest);
    > > int test__thread_mg_share(int subtest);
    > > diff --git a/tools/perf/util/Build b/tools/perf/util/Build
    > > index fb4f42f1bb38..0b98534a9ea1 100644
    > > --- a/tools/perf/util/Build
    > > +++ b/tools/perf/util/Build
    > > @@ -90,6 +90,7 @@ libperf-y += mem-events.o
    > > libperf-y += vsprintf.o
    > > libperf-y += drv_configs.o
    > > libperf-y += time-utils.o
    > > +libperf-y += expr-bison.o
    > >
    > > libperf-$(CONFIG_LIBBPF) += bpf-loader.o
    > > libperf-$(CONFIG_BPF_PROLOGUE) += bpf-prologue.o
    > > @@ -142,6 +143,10 @@ $(OUTPUT)util/parse-events-bison.c: util/parse-events.y
    > > $(call rule_mkdir)
    > > $(Q)$(call echo-cmd,bison)$(BISON) -v util/parse-events.y -d $(PARSER_DEBUG_BISON) -o $@ -p parse_events_
    > >
    > > +$(OUTPUT)util/expr-bison.c: util/expr.y
    > > + $(call rule_mkdir)
    > > + $(Q)$(call echo-cmd,bison)$(BISON) -v util/expr.y -d $(PARSER_DEBUG_BISON) -o $@ -p expr__
    > > +
    > > $(OUTPUT)util/pmu-flex.c: util/pmu.l $(OUTPUT)util/pmu-bison.c
    > > $(call rule_mkdir)
    > > $(Q)$(call echo-cmd,flex)$(FLEX) -o $@ --header-file=$(OUTPUT)util/pmu-flex.h util/pmu.l
    > > diff --git a/tools/perf/util/expr.h b/tools/perf/util/expr.h
    > > new file mode 100644
    > > index 000000000000..9c2760a1a96e
    > > --- /dev/null
    > > +++ b/tools/perf/util/expr.h
    > > @@ -0,0 +1,25 @@
    > > +#ifndef PARSE_CTX_H
    > > +#define PARSE_CTX_H 1
    > > +
    > > +#define EXPR_MAX_OTHER 8
    > > +#define MAX_PARSE_ID EXPR_MAX_OTHER
    > > +
    > > +struct parse_id {
    > > + const char *name;
    > > + double val;
    > > +};
    > > +
    > > +struct parse_ctx {
    > > + int num_ids;
    > > + struct parse_id ids[MAX_PARSE_ID];
    > > +};
    > > +
    > > +void expr__ctx_init(struct parse_ctx *ctx);
    > > +void expr__add_id(struct parse_ctx *ctx, const char *id, double val);
    > > +#ifndef IN_EXPR_Y
    > > +int expr__parse(double *final_val, struct parse_ctx *ctx, const char **pp);
    > > +#endif
    > > +int expr__find_other(const char *p, const char *one, const char ***other,
    > > + int *num_other);
    > > +
    > > +#endif
    > > diff --git a/tools/perf/util/expr.y b/tools/perf/util/expr.y
    > > new file mode 100644
    > > index 000000000000..a8daa7a93605
    > > --- /dev/null
    > > +++ b/tools/perf/util/expr.y
    > > @@ -0,0 +1,173 @@
    > > +/* Simple expression parser */
    > > +%{
    > > +#include "util.h"
    > > +#include "util/debug.h"
    > > +#define IN_EXPR_Y 1
    > > +#include "expr.h"
    > > +#include <string.h>
    > > +
    > > +#define MAXIDLEN 256
    > > +%}
    > > +
    > > +%define api.pure full
    > > +%parse-param { double *final_val }
    > > +%parse-param { struct parse_ctx *ctx }
    > > +%parse-param { const char **pp }
    > > +%lex-param { const char **pp }
    > > +
    > > +%union {
    > > + double num;
    > > + char id[MAXIDLEN+1];
    > > +}
    > > +
    > > +%token <num> NUMBER
    > > +%token <id> ID
    > > +%left '|'
    > > +%left '^'
    > > +%left '&'
    > > +%left '-' '+'
    > > +%left '*' '/' '%'
    > > +%left NEG NOT
    > > +%type <num> expr
    > > +
    > > +%{
    > > +static int expr__lex(YYSTYPE *res, const char **pp);
    > > +
    > > +static void expr__error(double *final_val __maybe_unused,
    > > + struct parse_ctx *ctx __maybe_unused,
    > > + const char **pp __maybe_unused,
    > > + const char *s)
    > > +{
    > > + pr_debug("%s\n", s);
    > > +}
    > > +
    > > +static int lookup_id(struct parse_ctx *ctx, char *id, double *val)
    > > +{
    > > + int i;
    > > +
    > > + for (i = 0; i < ctx->num_ids; i++) {
    > > + if (!strcasecmp(ctx->ids[i].name, id)) {
    > > + *val = ctx->ids[i].val;
    > > + return 0;
    > > + }
    > > + }
    > > + return -1;
    > > +}
    > > +
    > > +%}
    > > +%%
    > > +
    > > +all_expr: expr { *final_val = $1; }
    > > + ;
    > > +
    > > +expr: NUMBER
    > > + | ID { if (lookup_id(ctx, $1, &$$) < 0) {
    > > + pr_debug("%s not found", $1);
    > > + YYABORT;
    > > + }
    > > + }
    > > + | expr '+' expr { $$ = $1 + $3; }
    > > + | expr '-' expr { $$ = $1 - $3; }
    > > + | expr '*' expr { $$ = $1 * $3; }
    > > + | expr '/' expr { if ($3 == 0) YYABORT; $$ = $1 / $3; }
    > > + | expr '%' expr { if ((long)$3 == 0) YYABORT; $$ = (long)$1 % (long)$3; }
    > > + | '-' expr %prec NEG { $$ = -$2; }
    > > + | '(' expr ')' { $$ = $2; }
    > > + ;
    > > +
    > > +%%
    > > +
    > > +static int expr__symbol(YYSTYPE *res, const char *p, const char **pp)
    > > +{
    > > + char *dst = res->id;
    > > + const char *s = p;
    > > +
    > > + while (isalnum(*p) || *p == '_' || *p == '.') {
    > > + if (p - s >= MAXIDLEN)
    > > + return -1;
    > > + *dst++ = *p++;
    > > + }
    > > + *dst = 0;
    > > + *pp = p;
    > > + return ID;
    > > +}
    > > +
    > > +static int expr__lex(YYSTYPE *res, const char **pp)
    > > +{
    > > + int tok;
    > > + const char *s;
    > > + const char *p = *pp;
    > > +
    > > + while (isspace(*p))
    > > + p++;
    > > + s = p;
    > > + switch (*p++) {
    > > + case 'a' ... 'z':
    > > + case 'A' ... 'Z':
    > > + return expr__symbol(res, p - 1, pp);
    > > + case '0' ... '9': case '.':
    > > + res->num = strtod(s, (char **)&p);
    > > + tok = NUMBER;
    > > + break;
    > > + default:
    > > + tok = *s;
    > > + break;
    > > + }
    > > + *pp = p;
    > > + return tok;
    > > +}
    > > +
    > > +/* Caller must make sure id is allocated */
    > > +void expr__add_id(struct parse_ctx *ctx, const char *name, double val)
    > > +{
    > > + int idx;
    > > + assert(ctx->num_ids < MAX_PARSE_ID);
    > > + idx = ctx->num_ids++;
    > > + ctx->ids[idx].name = name;
    > > + ctx->ids[idx].val = val;
    > > +}
    > > +
    > > +void expr__ctx_init(struct parse_ctx *ctx)
    > > +{
    > > + ctx->num_ids = 0;
    > > +}
    > > +
    > > +int expr__find_other(const char *p, const char *one, const char ***other,
    > > + int *num_otherp)
    > > +{
    > > + const char *orig = p;
    > > + int err = -1;
    > > + int num_other;
    > > +
    > > + *other = malloc((EXPR_MAX_OTHER + 1) * sizeof(char *));
    > > + if (!*other)
    > > + return -1;
    > > +
    > > + num_other = 0;
    > > + for (;;) {
    > > + YYSTYPE val;
    > > + int tok = expr__lex(&val, &p);
    > > + if (tok == 0) {
    > > + err = 0;
    > > + break;
    > > + }
    > > + if (tok == ID && strcasecmp(one, val.id)) {
    > > + if (num_other >= EXPR_MAX_OTHER - 1) {
    > > + pr_debug("Too many extra events in %s\n", orig);
    > > + break;
    > > + }
    > > + (*other)[num_other] = strdup(val.id);
    > > + if (!(*other)[num_other])
    > > + return -1;
    > > + num_other++;
    > > + }
    > > + }
    > > + (*other)[num_other] = NULL;
    > > + *num_otherp = num_other;
    > > + if (err) {
    > > + *num_otherp = 0;
    > > + free(*other);
    > > + *other = NULL;
    > > + }
    > > + return err;
    > > +}
    > > --
    > > 2.9.3

    \
     
     \ /
      Last update: 2017-03-21 20:20    [W:7.259 / U:1.056 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site