perf expr: Add literal values starting with #

It is useful to have literal values for constants relating to
topologies, SMT, etc. Make the parsing of literals shared code and add a
lookup function. Move #smt_on to this function.

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul A . Clarke <pc@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Riccardo Mancini <rickyman7@gmail.com>
Cc: Song Liu <song@kernel.org>
Cc: Wan Jiabing <wanjiabing@vivo.com>
Cc: Yury Norov <yury.norov@gmail.com>
Link: https://lore.kernel.org/r/20211111002109.194172-6-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/expr.c

@@ -9,9 +9,11 @@
 #include "expr.h"
 #include "expr-bison.h"
 #include "expr-flex.h"
+#include "smt.h"
 #include <linux/kernel.h>
 #include <linux/zalloc.h>
 #include <ctype.h>
+#include <math.h>
 
 #ifdef PARSER_DEBUG
 extern int expr_debug;
@@ -370,3 +372,12 @@ double expr_id_data__value(const struct expr_id_data *data)
 	assert(data->kind == EXPR_ID_DATA__REF_VALUE);
 	return data->ref.val;
 }
+
+double expr__get_literal(const char *literal)
+{
+	if (!strcmp("#smt_on", literal))
+		return smt_on() > 0 ? 1.0 : 0.0;
+
+	pr_err("Unrecognized literal '%s'", literal);
+	return NAN;
+}

tools/perf/util/expr.h

@@ -55,5 +55,6 @@ int expr__find_ids(const char *expr, const char *one,
 		   struct expr_parse_ctx *ids);
 
 double expr_id_data__value(const struct expr_id_data *data);
+double expr__get_literal(const char *literal);
 
 #endif

tools/perf/util/expr.l

@@ -6,6 +6,7 @@
 #include <linux/compiler.h>
 #include "expr.h"
 #include "expr-bison.h"
+#include <math.h>
 
 char *expr_get_text(yyscan_t yyscanner);
 YYSTYPE *expr_get_lval(yyscan_t yyscanner);
@@ -77,6 +78,17 @@ static int str(yyscan_t scanner, int token, int runtime)
 	yylval->str = normalize(yylval->str, runtime);
 	return token;
 }
+
+static int literal(yyscan_t scanner)
+{
+	YYSTYPE *yylval = expr_get_lval(scanner);
+
+	yylval->num = expr__get_literal(expr_get_text(scanner));
+	if (isnan(yylval->num))
+		return EXPR_ERROR;
+
+	return LITERAL;
+}
 %}
 
 number		([0-9]+\.?[0-9]*|[0-9]*\.?[0-9]+)
@@ -85,6 +97,7 @@ sch		[-,=]
 spec		\\{sch}
 sym		[0-9a-zA-Z_\.:@?]+
 symbol		({spec}|{sym})+
+literal		#[0-9a-zA-Z_\.\-]+
 
 %%
 	struct expr_scanner_ctx *sctx = expr_get_extra(yyscanner);
@@ -94,7 +107,7 @@ max		{ return MAX; }
 min		{ return MIN; }
 if		{ return IF; }
 else		{ return ELSE; }
-#smt_on		{ return SMT_ON; }
+{literal}	{ return literal(yyscanner); }
 {number}	{ return value(yyscanner); }
 {symbol}	{ return str(yyscanner, ID, sctx->runtime); }
 "|"		{ return '|'; }

tools/perf/util/expr.y

@@ -4,7 +4,6 @@
 #include <assert.h>
 #include <math.h>
 #include "util/debug.h"
-#include "smt.h"
 #define IN_EXPR_Y 1
 #include "expr.h"
 %}
@@ -37,7 +36,7 @@
 	} ids;
 }
 
-%token ID NUMBER MIN MAX IF ELSE SMT_ON D_RATIO EXPR_ERROR
+%token ID NUMBER MIN MAX IF ELSE LITERAL D_RATIO EXPR_ERROR
 %left MIN MAX IF
 %left '|'
 %left '^'
@@ -46,7 +45,7 @@
 %left '-' '+'
 %left '*' '/' '%'
 %left NEG NOT
-%type <num> NUMBER
+%type <num> NUMBER LITERAL
 %type <str> ID
 %destructor { free ($$); } <str>
 %type <ids> expr if_expr
@@ -280,9 +279,9 @@ expr: NUMBER
 		$$ = union_expr($3, $5);
 	}
 }
-| SMT_ON
+| LITERAL
 {
-	$$.val = smt_on() > 0 ? 1.0 : 0.0;
+	$$.val = $1;
 	$$.ids = NULL;
 }
 ;