perf/probes: Improve probe point syntax of perf-probe

This changes probe point syntax of perf-probe as below

 <SRC>[:ABS_LN] [ARGS]
 or
 <FUNC>[+OFFS|%return][@SRC] [ARGS]

And event name and event group name are automatically
generated based on probe-symbol and offset as below.

 perfprobes/SYMBOL_OFFSET[_NUM]

Where SYMBOL is the probing symbol and OFFSET is
the byte offset from the symbol.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
LKML-Reference: <20091027204310.30545.84984.stgit@harusame>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

3 files changed, 123 insertions, 70 deletions

diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index 3370dabed15d..92b4c491f23d 100644
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -52,6 +52,7 @@ const char *default_search_path[NR_SEARCH_PATH] = {
 #define MAX_PATH_LEN 256
 #define MAX_PROBES 128
 #define MAX_PROBE_ARGS 128
+#define PERFPROBE_GROUP "perfprobe"
 
 /* Session management structure */
 static struct {
@@ -60,20 +61,100 @@ static struct {
         int need_dwarf;
         int nr_probe;
         struct probe_point probes[MAX_PROBES];
-        char *events[MAX_PROBES];
 } session;
 
 #define semantic_error(msg ...) die("Semantic error :" msg)
 
-/* Parse a probe point. Note that any error must die. */
-static void parse_probepoint(const char *str)
+/* Parse probe point. Return 1 if return probe */
+static void parse_probe_point(char *arg, struct probe_point *pp)
+{
+        char *ptr, *tmp;
+        char c, nc;
+        /*
+         * <Syntax>
+         * perf probe SRC:LN
+         * perf probe FUNC[+OFFS|%return][@SRC]
+         */
+
+        ptr = strpbrk(arg, ":+@%");
+        if (ptr) {
+                nc = *ptr;
+                *ptr++ = '\0';
+        }
+
+        /* Check arg is function or file and copy it */
+        if (strchr(arg, '.'))   /* File */
+                pp->file = strdup(arg);
+        else                    /* Function */
+                pp->function = strdup(arg);
+        DIE_IF(pp->file == NULL && pp->function == NULL);
+
+        /* Parse other options */
+        while (ptr) {
+                arg = ptr;
+                c = nc;
+                ptr = strpbrk(arg, ":+@%");
+                if (ptr) {
+                        nc = *ptr;
+                        *ptr++ = '\0';
+                }
+                switch (c) {
+                case ':':       /* Line number */
+                        pp->line = strtoul(arg, &tmp, 0);
+                        if (*tmp != '\0')
+                                semantic_error("There is non-digit charactor"
+                                                " in line number.");
+                        break;
+                case '+':       /* Byte offset from a symbol */
+                        pp->offset = strtoul(arg, &tmp, 0);
+                        if (*tmp != '\0')
+                                semantic_error("There is non-digit charactor"
+                                                " in offset.");
+                        break;
+                case '@':       /* File name */
+                        if (pp->file)
+                                semantic_error("SRC@SRC is not allowed.");
+                        pp->file = strdup(arg);
+                        DIE_IF(pp->file == NULL);
+                        if (ptr)
+                                semantic_error("@SRC must be the last "
+                                               "option.");
+                        break;
+                case '%':       /* Probe places */
+                        if (strcmp(arg, "return") == 0) {
+                                pp->retprobe = 1;
+                        } else  /* Others not supported yet */
+                                semantic_error("%%%s is not supported.", arg);
+                        break;
+                default:
+                        DIE_IF("Program has a bug.");
+                        break;
+                }
+        }
+
+        /* Exclusion check */
+        if (pp->line && pp->function)
+                semantic_error("Function-relative line number is not"
+                                " supported yet.");
+        if (!pp->line && pp->file && !pp->function)
+                semantic_error("File always requires line number.");
+        if (pp->offset && !pp->function)
+                semantic_error("Offset requires an entry function.");
+        if (pp->retprobe && !pp->function)
+                semantic_error("Return probe requires an entry function.");
+        if (pp->offset && pp->retprobe)
+                semantic_error("Offset can't be used with return probe.");
+
+        pr_debug("symbol:%s file:%s line:%d offset:%d, return:%d\n",
+                 pp->function, pp->file, pp->line, pp->offset, pp->retprobe);
+}
+
+/* Parse an event definition. Note that any error must die. */
+static void parse_probe_event(const char *str)
 {
         char *argv[MAX_PROBE_ARGS + 2]; /* Event + probe + args */
         int argc, i;
-        char *arg, *ptr;
         struct probe_point *pp = &session.probes[session.nr_probe];
-        char **event = &session.events[session.nr_probe];
-        int retp = 0;
 
         pr_debug("probe-definition(%d): %s\n", session.nr_probe, str);
         if (++session.nr_probe == MAX_PROBES)
@@ -103,70 +184,28 @@ static void parse_probepoint(const char *str)
                         pr_debug("argv[%d]=%s\n", argc, argv[argc - 1]);
                 }
         } while (*str != '\0');
-        if (argc < 2)
-                semantic_error("Need event-name and probe-point at least.");
-
-        /* Parse the event name */
-        if (argv[0][0] == 'r')
-                retp = 1;
-        else if (argv[0][0] != 'p')
-                semantic_error("You must specify 'p'(kprobe) or"
-                                " 'r'(kretprobe) first.");
-        /* TODO: check event name */
-        *event = argv[0];
+        if (!argc)
+                semantic_error("An empty argument.");
 
         /* Parse probe point */
-        arg = argv[1];
-        if (arg[0] == '@') {
-                /* Source Line */
-                arg++;
-                ptr = strchr(arg, ':');
-                if (!ptr || !isdigit(ptr[1]))
-                        semantic_error("Line number is required.");
-                *ptr++ = '\0';
-                if (strlen(arg) == 0)
-                        semantic_error("No file name.");
-                pp->file = strdup(arg);
-                pp->line = atoi(ptr);
-                if (!pp->file || !pp->line)
-                        semantic_error("Failed to parse line.");
-                pr_debug("file:%s line:%d\n", pp->file, pp->line);
-        } else {
-                /* Function name */
-                ptr = strchr(arg, '+');
-                if (ptr) {
-                        if (!isdigit(ptr[1]))
-                                semantic_error("Offset is required.");
-                        *ptr++ = '\0';
-                        pp->offset = atoi(ptr);
-                } else
-                        ptr = arg;
-                ptr = strchr(ptr, '@');
-                if (ptr) {
-                        *ptr++ = '\0';
-                        pp->file = strdup(ptr);
-                }
-                pp->function = strdup(arg);
-                pr_debug("symbol:%s file:%s offset:%d\n",
-                         pp->function, pp->file, pp->offset);
-        }
-        free(argv[1]);
+        parse_probe_point(argv[0], pp);
+        free(argv[0]);
         if (pp->file)
                 session.need_dwarf = 1;
 
         /* Copy arguments */
-        pp->nr_args = argc - 2;
+        pp->nr_args = argc - 1;
         if (pp->nr_args > 0) {
                 pp->args = (char **)malloc(sizeof(char *) * pp->nr_args);
                 if (!pp->args)
                         die("malloc");
-                memcpy(pp->args, &argv[2], sizeof(char *) * pp->nr_args);
+                memcpy(pp->args, &argv[1], sizeof(char *) * pp->nr_args);
         }
 
         /* Ensure return probe has no C argument */
         for (i = 0; i < pp->nr_args; i++)
                 if (is_c_varname(pp->args[i])) {
-                        if (retp)
+                        if (pp->retprobe)
                                 semantic_error("You can't specify local"
                                                 " variable for kretprobe");
                         session.need_dwarf = 1;
@@ -175,11 +214,11 @@ static void parse_probepoint(const char *str)
         pr_debug("%d arguments\n", pp->nr_args);
 }
 
-static int opt_add_probepoint(const struct option *opt __used,
+static int opt_add_probe_event(const struct option *opt __used,
                               const char *str, int unset __used)
 {
         if (str)
-                parse_probepoint(str);
+                parse_probe_event(str);
         return 0;
 }
 
@@ -229,17 +268,16 @@ static const struct option options[] = {
 #endif
         OPT_CALLBACK('a', "add", NULL,
 #ifdef NO_LIBDWARF
-                "p|r:[GRP/]NAME FUNC[+OFFS] [ARG ...]",
+                "FUNC[+OFFS|%return] [ARG ...]",
 #else
-                "p|r:[GRP/]NAME FUNC[+OFFS][@SRC]|@SRC:LINE [ARG ...]",
+                "FUNC[+OFFS|%return][@SRC]|SRC:LINE [ARG ...]",
 #endif
                 "probe point definition, where\n"
-                "\t\tp:\tkprobe probe\n"
-                "\t\tr:\tkretprobe probe\n"
                 "\t\tGRP:\tGroup name (optional)\n"
                 "\t\tNAME:\tEvent name\n"
                 "\t\tFUNC:\tFunction name\n"
                 "\t\tOFFS:\tOffset from function entry (in byte)\n"
+                "\t\t%return:\tPut the probe at function return\n"
 #ifdef NO_LIBDWARF
                 "\t\tARG:\tProbe argument (only \n"
 #else
@@ -248,7 +286,7 @@ static const struct option options[] = {
                 "\t\tARG:\tProbe argument (local variable name or\n"
 #endif
                 "\t\t\tkprobe-tracer argument format is supported.)\n",
-                opt_add_probepoint),
+                opt_add_probe_event),
         OPT_END()
 };
 
@@ -266,7 +304,7 @@ static int write_new_event(int fd, const char *buf)
 
 #define MAX_CMDLEN 256
 
-static int synthesize_probepoint(struct probe_point *pp)
+static int synthesize_probe_event(struct probe_point *pp)
 {
         char *buf;
         int i, len, ret;
@@ -316,12 +354,12 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
         /* Synthesize probes without dwarf */
         for (j = 0; j < session.nr_probe; j++) {
 #ifndef NO_LIBDWARF
-                if (session.events[j][0] != 'r') {
+                if (!session.probes[j].retprobe) {
                         session.need_dwarf = 1;
                         continue;
                 }
 #endif
-                ret = synthesize_probepoint(&session.probes[j]);
+                ret = synthesize_probe_event(&session.probes[j]);
                 if (ret == -E2BIG)
                         semantic_error("probe point is too long.");
                 else if (ret < 0)
@@ -349,7 +387,6 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
                 ret = find_probepoint(fd, pp);
                 if (ret <= 0)
                         die("No probe point found.\n");
-                pr_debug("probe event %s found\n", session.events[j]);
         }
         close(fd);
 
@@ -364,13 +401,17 @@ setup_probes:
         for (j = 0; j < session.nr_probe; j++) {
                 pp = &session.probes[j];
                 if (pp->found == 1) {
-                        snprintf(buf, MAX_CMDLEN, "%s %s\n",
-                                session.events[j], pp->probes[0]);
+                        snprintf(buf, MAX_CMDLEN, "%c:%s/%s_%x %s\n",
+                                pp->retprobe ? 'r' : 'p', PERFPROBE_GROUP,
+                                pp->function, pp->offset, pp->probes[0]);
                         write_new_event(fd, buf);
                 } else
                         for (i = 0; i < pp->found; i++) {
-                                snprintf(buf, MAX_CMDLEN, "%s%d %s\n",
-                                        session.events[j], i, pp->probes[i]);
+                                snprintf(buf, MAX_CMDLEN, "%c:%s/%s_%x_%d %s\n",
+                                        pp->retprobe ? 'r' : 'p',
+                                        PERFPROBE_GROUP,
+                                        pp->function, pp->offset, i,
+                                        pp->probes[0]);
                                 write_new_event(fd, buf);
                         }
         }
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index b98d35ef7116..6d3bac9f9473 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -483,10 +483,20 @@ static void show_probepoint(Dwarf_Die sp_die, Dwarf_Signed offs,
         if (ret == DW_DLV_OK) {
                 ret = snprintf(tmp, MAX_PROBE_BUFFER, "%s+%u", name,
                                 (unsigned int)offs);
+                /* Copy the function name if possible */
+                if (!pp->function) {
+                        pp->function = strdup(name);
+                        pp->offset = offs;
+                }
                 dwarf_dealloc(__dw_debug, name, DW_DLA_STRING);
         } else {
                 /* This function has no name. */
                 ret = snprintf(tmp, MAX_PROBE_BUFFER, "0x%llx", pf->addr);
+                if (!pp->function) {
+                        /* TODO: Use _stext */
+                        pp->function = strdup("");
+                        pp->offset = (int)pf->addr;
+                }
         }
         DIE_IF(ret < 0);
         DIE_IF(ret >= MAX_PROBE_BUFFER);
diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index d17fafc21351..240d6cb3cc2e 100644
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -22,6 +22,8 @@ struct probe_point {
         int     nr_args;        /* Number of arguments */
         char    **args;         /* Arguments */
 
+        int     retprobe;       /* Return probe */
+
         /* Output */
         int     found;          /* Number of found probe points */
         char    *probes[MAX_PROBES];    /* Output buffers (will be allocated)*/