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	YYDEBUG enables line numbers and other error helpers in the generated expr-bison.c. These shouldn't be generated when debugging isn't enabled. Signed-off-by: Ian Rogers <irogers@google.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Gaosheng Cui <cuigaosheng1@huawei.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Clark <james.clark@arm.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rob Herring <robh@kernel.org> Cc: bpf@vger.kernel.org Link: https://lore.kernel.org/r/20230911170559.4037734-3-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
		
			
				
	
	
		
			381 lines
		
	
	
	
		
			8.4 KiB
		
	
	
	
		
			Text
		
	
	
	
	
	
			
		
		
	
	
			381 lines
		
	
	
	
		
			8.4 KiB
		
	
	
	
		
			Text
		
	
	
	
	
	
/* Simple expression parser */
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%{
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#ifndef NDEBUG
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#define YYDEBUG 1
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#endif
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#include <assert.h>
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#include <math.h>
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#include <stdlib.h>
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#include "util/debug.h"
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#define IN_EXPR_Y 1
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#include "expr.h"
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#include "expr-bison.h"
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int expr_lex(YYSTYPE * yylval_param , void *yyscanner);
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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 { bool compute_ids }
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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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	struct ids {
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		/*
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		 * When creating ids, holds the working set of event ids. NULL
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		 * implies the set is empty.
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		 */
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		struct hashmap *ids;
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		/*
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		 * The metric value. When not creating ids this is the value
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		 * read from a counter, a constant or some computed value. When
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		 * creating ids the value is either a constant or BOTTOM. NAN is
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		 * used as the special BOTTOM value, representing a "set of all
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		 * values" case.
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		 */
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		double val;
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	} ids;
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}
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%token ID NUMBER MIN MAX IF ELSE LITERAL D_RATIO SOURCE_COUNT HAS_EVENT STRCMP_CPUID_STR EXPR_ERROR
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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 '*' '/' '%'
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%left NEG NOT
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%type <num> NUMBER LITERAL
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%type <str> ID
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%destructor { free ($$); } <str>
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%type <ids> expr if_expr
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%destructor { ids__free($$.ids); } <ids>
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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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		       bool compute_ids __maybe_unused,
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		       void *scanner __maybe_unused,
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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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 * During compute ids, the special "bottom" value uses NAN to represent the set
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 * of all values. NAN is selected as it isn't a useful constant value.
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 */
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#define BOTTOM NAN
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/* During computing ids, does val represent a constant (non-BOTTOM) value? */
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static bool is_const(double val)
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{
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	return isfinite(val);
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}
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static struct ids union_expr(struct ids ids1, struct ids ids2)
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{
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	struct ids result = {
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		.val = BOTTOM,
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		.ids = ids__union(ids1.ids, ids2.ids),
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	};
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	return result;
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}
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static struct ids handle_id(struct expr_parse_ctx *ctx, char *id,
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			    bool compute_ids, bool source_count)
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{
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	struct ids result;
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	if (!compute_ids) {
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		/*
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		 * Compute the event's value from ID. If the ID isn't known then
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		 * it isn't used to compute the formula so set to NAN.
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		 */
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		struct expr_id_data *data;
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		result.val = NAN;
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		if (expr__resolve_id(ctx, id, &data) == 0) {
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			result.val = source_count
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				? expr_id_data__source_count(data)
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				: expr_id_data__value(data);
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		}
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		result.ids = NULL;
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		free(id);
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	} else {
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		/*
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		 * Set the value to BOTTOM to show that any value is possible
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		 * when the event is computed. Create a set of just the ID.
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		 */
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		result.val = BOTTOM;
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		result.ids = ids__new();
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		if (!result.ids || ids__insert(result.ids, id)) {
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			pr_err("Error creating IDs for '%s'", id);
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			free(id);
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		}
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	}
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	return result;
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}
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/*
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 * If we're not computing ids or $1 and $3 are constants, compute the new
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 * constant value using OP. Its invariant that there are no ids.  If computing
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 * ids for non-constants union the set of IDs that must be computed.
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 */
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#define BINARY_OP(RESULT, OP, LHS, RHS)					\
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	if (!compute_ids || (is_const(LHS.val) && is_const(RHS.val))) { \
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		assert(LHS.ids == NULL);				\
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		assert(RHS.ids == NULL);				\
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		if (isnan(LHS.val) || isnan(RHS.val)) {			\
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			RESULT.val = NAN;				\
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		} else {						\
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			RESULT.val = LHS.val OP RHS.val;		\
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		}							\
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		RESULT.ids = NULL;					\
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	} else {							\
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	        RESULT = union_expr(LHS, RHS);				\
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	}
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%}
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%%
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start: if_expr
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{
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	if (compute_ids)
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		ctx->ids = ids__union($1.ids, ctx->ids);
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	if (final_val)
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		*final_val = $1.val;
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}
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;
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if_expr: expr IF expr ELSE if_expr
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{
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	if (fpclassify($3.val) == FP_ZERO) {
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		/*
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		 * The IF expression evaluated to 0 so treat as false, take the
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		 * ELSE and discard everything else.
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		 */
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		$$.val = $5.val;
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		$$.ids = $5.ids;
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		ids__free($1.ids);
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		ids__free($3.ids);
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	} else if (!compute_ids || is_const($3.val)) {
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		/*
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		 * If ids aren't computed then treat the expression as true. If
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		 * ids are being computed and the IF expr is a non-zero
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		 * constant, then also evaluate the true case.
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		 */
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		$$.val = $1.val;
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		$$.ids = $1.ids;
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		ids__free($3.ids);
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		ids__free($5.ids);
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	} else if ($1.val == $5.val) {
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		/*
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		 * LHS == RHS, so both are an identical constant. No need to
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		 * evaluate any events.
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		 */
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		$$.val = $1.val;
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		$$.ids = NULL;
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		ids__free($1.ids);
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		ids__free($3.ids);
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		ids__free($5.ids);
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	} else {
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		/*
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		 * Value is either the LHS or RHS and we need the IF expression
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		 * to compute it.
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		 */
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		$$ = union_expr($1, union_expr($3, $5));
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	}
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}
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| expr
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;
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expr: NUMBER
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{
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	$$.val = $1;
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	$$.ids = NULL;
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}
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| ID				{ $$ = handle_id(ctx, $1, compute_ids, /*source_count=*/false); }
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| SOURCE_COUNT '(' ID ')'	{ $$ = handle_id(ctx, $3, compute_ids, /*source_count=*/true); }
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| HAS_EVENT '(' ID ')'
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{
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	$$.val = expr__has_event(ctx, compute_ids, $3);
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	$$.ids = NULL;
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	free($3);
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}
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| STRCMP_CPUID_STR '(' ID ')'
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{
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	$$.val = expr__strcmp_cpuid_str(ctx, compute_ids, $3);
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	$$.ids = NULL;
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	free($3);
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}
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| expr '|' expr
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{
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	if (is_const($1.val) && is_const($3.val)) {
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		assert($1.ids == NULL);
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		assert($3.ids == NULL);
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		$$.ids = NULL;
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		$$.val = (fpclassify($1.val) == FP_ZERO && fpclassify($3.val) == FP_ZERO) ? 0 : 1;
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	} else if (is_const($1.val)) {
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		assert($1.ids == NULL);
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		if (fpclassify($1.val) == FP_ZERO) {
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			$$ = $3;
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		} else {
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			$$.val = 1;
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			$$.ids = NULL;
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			ids__free($3.ids);
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		}
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	} else if (is_const($3.val)) {
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		assert($3.ids == NULL);
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		if (fpclassify($3.val) == FP_ZERO) {
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			$$ = $1;
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		} else {
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			$$.val = 1;
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			$$.ids = NULL;
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			ids__free($1.ids);
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		}
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	} else {
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		$$ = union_expr($1, $3);
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	}
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}
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| expr '&' expr
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{
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	if (is_const($1.val) && is_const($3.val)) {
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		assert($1.ids == NULL);
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		assert($3.ids == NULL);
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		$$.val = (fpclassify($1.val) != FP_ZERO && fpclassify($3.val) != FP_ZERO) ? 1 : 0;
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		$$.ids = NULL;
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	} else if (is_const($1.val)) {
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		assert($1.ids == NULL);
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		if (fpclassify($1.val) != FP_ZERO) {
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			$$ = $3;
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		} else {
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			$$.val = 0;
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			$$.ids = NULL;
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			ids__free($3.ids);
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		}
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	} else if (is_const($3.val)) {
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		assert($3.ids == NULL);
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		if (fpclassify($3.val) != FP_ZERO) {
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			$$ = $1;
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		} else {
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			$$.val = 0;
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			$$.ids = NULL;
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			ids__free($1.ids);
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		}
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	} else {
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		$$ = union_expr($1, $3);
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	}
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}
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| expr '^' expr
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{
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	if (is_const($1.val) && is_const($3.val)) {
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		assert($1.ids == NULL);
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		assert($3.ids == NULL);
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		$$.val = (fpclassify($1.val) == FP_ZERO) != (fpclassify($3.val) == FP_ZERO) ? 1 : 0;
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		$$.ids = NULL;
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	} else {
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		$$ = union_expr($1, $3);
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	}
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}
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| expr '<' expr { BINARY_OP($$, <, $1, $3); }
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| expr '>' expr { BINARY_OP($$, >, $1, $3); }
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| expr '+' expr { BINARY_OP($$, +, $1, $3); }
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| expr '-' expr { BINARY_OP($$, -, $1, $3); }
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| expr '*' expr { BINARY_OP($$, *, $1, $3); }
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| expr '/' expr
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{
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	if (fpclassify($3.val) == FP_ZERO) {
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		pr_debug("division by zero\n");
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		assert($3.ids == NULL);
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		if (compute_ids)
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			ids__free($1.ids);
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		$$.val = NAN;
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		$$.ids = NULL;
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	} else if (!compute_ids || (is_const($1.val) && is_const($3.val))) {
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		assert($1.ids == NULL);
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		assert($3.ids == NULL);
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		$$.val = $1.val / $3.val;
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		$$.ids = NULL;
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	} else {
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		/* LHS and/or RHS need computing from event IDs so union. */
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		$$ = union_expr($1, $3);
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	}
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}
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| expr '%' expr
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{
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	if (fpclassify($3.val) == FP_ZERO) {
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		pr_debug("division by zero\n");
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		YYABORT;
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	} else if (!compute_ids || (is_const($1.val) && is_const($3.val))) {
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		assert($1.ids == NULL);
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		assert($3.ids == NULL);
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		$$.val = (long)$1.val % (long)$3.val;
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		$$.ids = NULL;
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	} else {
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		/* LHS and/or RHS need computing from event IDs so union. */
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		$$ = union_expr($1, $3);
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	}
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}
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| D_RATIO '(' expr ',' expr ')'
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{
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	if (fpclassify($5.val) == FP_ZERO) {
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		/*
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		 * Division by constant zero always yields zero and no events
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		 * are necessary.
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		 */
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		assert($5.ids == NULL);
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		$$.val = 0.0;
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		$$.ids = NULL;
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		ids__free($3.ids);
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	} else if (!compute_ids || (is_const($3.val) && is_const($5.val))) {
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		assert($3.ids == NULL);
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		assert($5.ids == NULL);
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		$$.val = $3.val / $5.val;
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		$$.ids = NULL;
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	} else {
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		/* LHS and/or RHS need computing from event IDs so union. */
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		$$ = union_expr($3, $5);
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	}
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}
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| '-' expr %prec NEG
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{
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	$$.val = -$2.val;
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	$$.ids = $2.ids;
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}
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| '(' if_expr ')'
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{
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	$$ = $2;
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}
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| MIN '(' expr ',' expr ')'
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{
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	if (!compute_ids) {
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		$$.val = $3.val < $5.val ? $3.val : $5.val;
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		$$.ids = NULL;
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	} else {
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		$$ = union_expr($3, $5);
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	}
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}
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| MAX '(' expr ',' expr ')'
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{
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	if (!compute_ids) {
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		$$.val = $3.val > $5.val ? $3.val : $5.val;
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		$$.ids = NULL;
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	} else {
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		$$ = union_expr($3, $5);
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	}
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}
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| LITERAL
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{
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	$$.val = $1;
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	$$.ids = NULL;
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}
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;
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%%
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