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Subject[tip:perf/probes] perf/probes: Support function entry relative line number
Commit-ID:  b0ef07324310d66f660a311d4a8d669eda74f801
Gitweb: http://git.kernel.org/tip/b0ef07324310d66f660a311d4a8d669eda74f801
Author: Masami Hiramatsu <mhiramat@redhat.com>
AuthorDate: Tue, 27 Oct 2009 16:43:19 -0400
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Thu, 29 Oct 2009 08:47:49 +0100

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>
---
tools/perf/builtin-probe.c | 14 ++++----
tools/perf/util/probe-finder.c | 79 +++++++++++++++++++++++++++++++---------
tools/perf/util/probe-finder.h | 2 +
3 files changed, 70 insertions(+), 25 deletions(-)

diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index 92b4c49..a99a366 100644
--- 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
--- 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
--- 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 */

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