forked from Minki/linux
ded80bda8b
Use a hashmap between a char* string and a double* value. While bpf's hashmap entries are size_t in size, we can't guarantee sizeof(size_t) >= sizeof(double). Avoid a memory allocation when gathering ids by making 0.0 a special value encoded as NULL. Original map suggestion by Andi Kleen: https://lore.kernel.org/lkml/20200224210308.GQ160988@tassilo.jf.intel.com/ and seconded by Jiri Olsa: https://lore.kernel.org/lkml/20200423112915.GH1136647@krava/ Committer notes: There are fixes that need to land upstream before we can use libbpf's headers, for now use our copy unconditionally, since the data structures at this point are exactly the same, no problem. When the fixes for libbpf's hashmap land upstream, we can fix this up. Testing it: Building with LIBBPF=1, i.e. the default: $ perf -vv | grep -i bpf bpf: [ on ] # HAVE_LIBBPF_SUPPORT $ nm ~/bin/perf | grep -i libbpf_ | wc -l 39 $ nm ~/bin/perf | grep -i hashmap_ | wc -l 17 $ Explicitely building without LIBBPF: $ perf -vv | grep -i bpf bpf: [ OFF ] # HAVE_LIBBPF_SUPPORT $ $ nm ~/bin/perf | grep -i libbpf_ | wc -l 0 $ nm ~/bin/perf | grep -i hashmap_ | wc -l 9 $ Signed-off-by: Ian Rogers <irogers@google.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andi Kleen <ak@linux.intel.com> Cc: Andrii Nakryiko <andriin@fb.com> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Jin Yao <yao.jin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: John Fastabend <john.fastabend@gmail.com> Cc: John Garry <john.garry@huawei.com> Cc: Kajol Jain <kjain@linux.ibm.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Kim Phillips <kim.phillips@amd.com> Cc: Leo Yan <leo.yan@linaro.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Martin KaFai Lau <kafai@fb.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Song Liu <songliubraving@fb.com> Cc: Stephane Eranian <eranian@google.com> Cc: Yonghong Song <yhs@fb.com> Cc: bpf@vger.kernel.org Cc: kp singh <kpsingh@chromium.org> Cc: netdev@vger.kernel.org Link: http://lore.kernel.org/lkml/20200515221732.44078-8-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
111 lines
2.1 KiB
Plaintext
111 lines
2.1 KiB
Plaintext
/* Simple expression parser */
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%{
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#define YYDEBUG 1
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#include <stdio.h>
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#include "util.h"
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#include "util/debug.h"
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#include <stdlib.h> // strtod()
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#define IN_EXPR_Y 1
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#include "expr.h"
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#include "smt.h"
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#include <string.h>
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%}
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%define api.pure full
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%parse-param { double *final_val }
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%parse-param { struct expr_parse_ctx *ctx }
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%parse-param {void *scanner}
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%lex-param {void* scanner}
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%union {
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double num;
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char *str;
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}
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%token EXPR_PARSE EXPR_OTHER EXPR_ERROR
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%token <num> NUMBER
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%token <str> ID
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%destructor { free ($$); } <str>
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%token MIN MAX IF ELSE SMT_ON
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%left MIN MAX IF
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%left '|'
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%left '^'
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%left '&'
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%left '-' '+'
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%left '*' '/' '%'
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%left NEG NOT
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%type <num> expr if_expr
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%{
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static void expr_error(double *final_val __maybe_unused,
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struct expr_parse_ctx *ctx __maybe_unused,
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void *scanner,
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const char *s)
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{
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pr_debug("%s\n", s);
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}
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%}
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%%
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start:
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EXPR_PARSE all_expr
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EXPR_OTHER all_other
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all_other: all_other other
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other: ID
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{
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expr__add_id(ctx, $1, 0.0);
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}
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MIN | MAX | IF | ELSE | SMT_ON | NUMBER | '|' | '^' | '&' | '-' | '+' | '*' | '/' | '%' | '(' | ')' | ','
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all_expr: if_expr { *final_val = $1; }
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;
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if_expr:
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expr IF expr ELSE expr { $$ = $3 ? $1 : $5; }
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| expr
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;
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expr: NUMBER
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| ID { if (expr__get_id(ctx, $1, &$$)) {
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pr_debug("%s not found\n", $1);
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free($1);
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YYABORT;
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}
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free($1);
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}
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| expr '|' expr { $$ = (long)$1 | (long)$3; }
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| expr '&' expr { $$ = (long)$1 & (long)$3; }
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| expr '^' expr { $$ = (long)$1 ^ (long)$3; }
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| expr '+' expr { $$ = $1 + $3; }
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| expr '-' expr { $$ = $1 - $3; }
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| expr '*' expr { $$ = $1 * $3; }
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| expr '/' expr { if ($3 == 0) {
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pr_debug("division by zero\n");
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YYABORT;
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}
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$$ = $1 / $3;
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}
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| expr '%' expr { if ((long)$3 == 0) {
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pr_debug("division by zero\n");
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YYABORT;
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}
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$$ = (long)$1 % (long)$3;
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}
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| '-' expr %prec NEG { $$ = -$2; }
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| '(' if_expr ')' { $$ = $2; }
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| MIN '(' expr ',' expr ')' { $$ = $3 < $5 ? $3 : $5; }
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| MAX '(' expr ',' expr ')' { $$ = $3 > $5 ? $3 : $5; }
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| SMT_ON { $$ = smt_on() > 0; }
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;
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%%
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