perf/probes: Support function entry relative line number

Add function-entry relative line number specifying support to
perf-probe. This allows users to define probes by line number
from entry of the function.

 e.g.

  perf probe schedule:16

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: <20091027204319.30545.30678.stgit@harusame>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index 92b4c49..a99a366 100644 (file)
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -133,17 +133,16 @@ static void parse_probe_point(char *arg, struct probe_point *pp)
        }
 
        /* Exclusion check */
-       if (pp->line && pp->function)
-               semantic_error("Function-relative line number is not"
-                               " supported yet.");
+       if (pp->line && pp->offset)
+               semantic_error("Offset can't be used with line number.");
        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.");
+       if ((pp->offset || pp->line) && pp->retprobe)
+               semantic_error("Offset/Line 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);
@@ -270,7 +269,7 @@ static const struct option options[] = {
 #ifdef NO_LIBDWARF
                "FUNC[+OFFS|%return] [ARG ...]",
 #else
-               "FUNC[+OFFS|%return][@SRC]|SRC:LINE [ARG ...]",
+               "FUNC[+OFFS|%return|:RLN][@SRC]|SRC:ALN [ARG ...]",
 #endif
                "probe point definition, where\n"
                "\t\tGRP:\tGroup name (optional)\n"
@@ -282,7 +281,8 @@ static const struct option options[] = {
                "\t\tARG:\tProbe argument (only \n"
 #else
                "\t\tSRC:\tSource code path\n"
-               "\t\tLINE:\tLine number\n"
+               "\t\tRLN:\tRelative line number from function entry.\n"
+               "\t\tALN:\tAbsolute line number in file.\n"
                "\t\tARG:\tProbe argument (local variable name or\n"
 #endif
                "\t\t\tkprobe-tracer argument format is supported.)\n",

diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index 6d3bac9..db96186 100644 (file)
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -114,7 +114,7 @@ static int strtailcmp(const char *s1, const char *s2)
 }
 
 /* Find the fileno of the target file. */
-static Dwarf_Unsigned die_get_fileno(Dwarf_Die cu_die, const char *fname)
+static Dwarf_Unsigned cu_find_fileno(Dwarf_Die cu_die, const char *fname)
 {
        Dwarf_Signed cnt, i;
        Dwarf_Unsigned found = 0;
@@ -335,6 +335,36 @@ static int attr_get_locdesc(Dwarf_Attribute attr, Dwarf_Locdesc *desc,
        return ret;
 }
 
+/* Get decl_file attribute value (file number) */
+static Dwarf_Unsigned die_get_decl_file(Dwarf_Die sp_die)
+{
+       Dwarf_Attribute attr;
+       Dwarf_Unsigned fno;
+       int ret;
+
+       ret = dwarf_attr(sp_die, DW_AT_decl_file, &attr, &__dw_error);
+       DIE_IF(ret != DW_DLV_OK);
+       dwarf_formudata(attr, &fno, &__dw_error);
+       DIE_IF(ret != DW_DLV_OK);
+       dwarf_dealloc(__dw_debug, attr, DW_DLA_ATTR);
+       return fno;
+}
+
+/* Get decl_line attribute value (line number) */
+static Dwarf_Unsigned die_get_decl_line(Dwarf_Die sp_die)
+{
+       Dwarf_Attribute attr;
+       Dwarf_Unsigned lno;
+       int ret;
+
+       ret = dwarf_attr(sp_die, DW_AT_decl_line, &attr, &__dw_error);
+       DIE_IF(ret != DW_DLV_OK);
+       dwarf_formudata(attr, &lno, &__dw_error);
+       DIE_IF(ret != DW_DLV_OK);
+       dwarf_dealloc(__dw_debug, attr, DW_DLA_ATTR);
+       return lno;
+}
+
 /*
  * Probe finder related functions
  */
@@ -501,6 +531,7 @@ static void show_probepoint(Dwarf_Die sp_die, Dwarf_Signed offs,
        DIE_IF(ret < 0);
        DIE_IF(ret >= MAX_PROBE_BUFFER);
        len = ret;
+       pr_debug("Probe point found: %s\n", tmp);
 
        /* Find each argument */
        get_current_frame_base(sp_die, pf);
@@ -536,17 +567,16 @@ static int probeaddr_callback(struct die_link *dlink, void *data)
 }
 
 /* Find probe point from its line number */
-static void find_by_line(Dwarf_Die cu_die, struct probe_finder *pf)
+static void find_by_line(struct probe_finder *pf)
 {
-       struct probe_point *pp = pf->pp;
-       Dwarf_Signed cnt, i;
+       Dwarf_Signed cnt, i, clm;
        Dwarf_Line *lines;
        Dwarf_Unsigned lineno = 0;
        Dwarf_Addr addr;
        Dwarf_Unsigned fno;
        int ret;
 
-       ret = dwarf_srclines(cu_die, &lines, &cnt, &__dw_error);
+       ret = dwarf_srclines(pf->cu_die, &lines, &cnt, &__dw_error);
        DIE_IF(ret != DW_DLV_OK);
 
        for (i = 0; i < cnt; i++) {
@@ -557,15 +587,20 @@ static void find_by_line(Dwarf_Die cu_die, struct probe_finder *pf)
 
                ret = dwarf_lineno(lines[i], &lineno, &__dw_error);
                DIE_IF(ret != DW_DLV_OK);
-               if (lineno != (Dwarf_Unsigned)pp->line)
+               if (lineno != pf->lno)
                        continue;
 
+               ret = dwarf_lineoff(lines[i], &clm, &__dw_error);
+               DIE_IF(ret != DW_DLV_OK);
+
                ret = dwarf_lineaddr(lines[i], &addr, &__dw_error);
                DIE_IF(ret != DW_DLV_OK);
-               pr_debug("Probe point found: 0x%llx\n", addr);
+               pr_debug("Probe line found: line[%d]:%u,%d addr:0x%llx\n",
+                        (int)i, (unsigned)lineno, (int)clm, addr);
                pf->addr = addr;
                /* Search a real subprogram including this line, */
-               ret = search_die_from_children(cu_die, probeaddr_callback, pf);
+               ret = search_die_from_children(pf->cu_die,
+                                              probeaddr_callback, pf);
                if (ret == 0)
                        die("Probe point is not found in subprograms.\n");
                /* Continuing, because target line might be inlined. */
@@ -587,6 +622,13 @@ static int probefunc_callback(struct die_link *dlink, void *data)
        DIE_IF(ret == DW_DLV_ERROR);
        if (tag == DW_TAG_subprogram) {
                if (die_compare_name(dlink->die, pp->function) == 0) {
+                       if (pp->line) { /* Function relative line */
+                               pf->fno = die_get_decl_file(dlink->die);
+                               pf->lno = die_get_decl_line(dlink->die)
+                                        + pp->line;
+                               find_by_line(pf);
+                               return 1;
+                       }
                        if (die_inlined_subprogram(dlink->die)) {
                                /* Inlined function, save it. */
                                ret = dwarf_die_CU_offset(dlink->die,
@@ -631,9 +673,9 @@ found:
        return 0;
 }
 
-static void find_by_func(Dwarf_Die cu_die, struct probe_finder *pf)
+static void find_by_func(struct probe_finder *pf)
 {
-       search_die_from_children(cu_die, probefunc_callback, pf);
+       search_die_from_children(pf->cu_die, probefunc_callback, pf);
 }
 
 /* Find a probe point */
@@ -641,7 +683,6 @@ int find_probepoint(int fd, struct probe_point *pp)
 {
        Dwarf_Half addr_size = 0;
        Dwarf_Unsigned next_cuh = 0;
-       Dwarf_Die cu_die = 0;
        int cu_number = 0, ret;
        struct probe_finder pf = {.pp = pp};
 
@@ -659,25 +700,27 @@ int find_probepoint(int fd, struct probe_point *pp)
                        break;
 
                /* Get the DIE(Debugging Information Entry) of this CU */
-               ret = dwarf_siblingof(__dw_debug, 0, &cu_die, &__dw_error);
+               ret = dwarf_siblingof(__dw_debug, 0, &pf.cu_die, &__dw_error);
                DIE_IF(ret != DW_DLV_OK);
 
                /* Check if target file is included. */
                if (pp->file)
-                       pf.fno = die_get_fileno(cu_die, pp->file);
+                       pf.fno = cu_find_fileno(pf.cu_die, pp->file);
 
                if (!pp->file || pf.fno) {
                        /* Save CU base address (for frame_base) */
-                       ret = dwarf_lowpc(cu_die, &pf.cu_base, &__dw_error);
+                       ret = dwarf_lowpc(pf.cu_die, &pf.cu_base, &__dw_error);
                        DIE_IF(ret == DW_DLV_ERROR);
                        if (ret == DW_DLV_NO_ENTRY)
                                pf.cu_base = 0;
-                       if (pp->line)
-                               find_by_line(cu_die, &pf);
                        if (pp->function)
-                               find_by_func(cu_die, &pf);
+                               find_by_func(&pf);
+                       else {
+                               pf.lno = pp->line;
+                               find_by_line(&pf);
+                       }
                }
-               dwarf_dealloc(__dw_debug, cu_die, DW_DLA_DIE);
+               dwarf_dealloc(__dw_debug, pf.cu_die, DW_DLA_DIE);
        }
        ret = dwarf_finish(__dw_debug, &__dw_error);
        DIE_IF(ret != DW_DLV_OK);

diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index 240d6cb..bdebca6 100644 (file)
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -41,7 +41,9 @@ struct probe_finder {
        /* For function searching */
        Dwarf_Addr      addr;           /* Address */
        Dwarf_Unsigned  fno;            /* File number */
+       Dwarf_Unsigned  lno;            /* Line number */
        Dwarf_Off       inl_offs;       /* Inline offset */
+       Dwarf_Die       cu_die;         /* Current CU */
 
        /* For variable searching */
        Dwarf_Addr      cu_base;        /* Current CU base address */