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Subject[tip:perf/probes] perf probe: Use libdw callback routines
Commit-ID:  e92b85e1ffaa0bd8e5d92e7c378a3909e7f23122
Gitweb: http://git.kernel.org/tip/e92b85e1ffaa0bd8e5d92e7c378a3909e7f23122
Author: Masami Hiramatsu <mhiramat@redhat.com>
AuthorDate: Thu, 25 Feb 2010 08:35:50 -0500
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Thu, 25 Feb 2010 17:49:29 +0100

perf probe: Use libdw callback routines

Use libdw callback functions aggressively, and remove
local tree-search API. This change simplifies the code.

Changes in v3:
- Cast Dwarf_Addr to uintmax_t for printf-formats.

Changes in v2:
- Cast Dwarf_Addr to unsigned long long for printf-formats.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
LKML-Reference: <20100225133549.6725.81499.stgit@localhost6.localdomain6>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
tools/perf/util/probe-finder.c | 262 +++++++++++++---------------------------
tools/perf/util/probe-finder.h | 1 -
2 files changed, 86 insertions(+), 177 deletions(-)
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index c422472..6305f34 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -38,13 +38,6 @@
#include "probe-finder.h"


-/* Dwarf_Die Linkage to parent Die */
-struct die_link {
- struct die_link *parent; /* Parent die */
- Dwarf_Die die; /* Current die */
-};
-
-
/*
* Generic dwarf analysis helpers
*/
@@ -177,26 +170,6 @@ static bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
return strcmp(tname, name);
}

-/* Check the address is in the subprogram(function). */
-static bool die_within_subprogram(Dwarf_Die *sp_die, Dwarf_Addr addr,
- size_t *offs)
-{
- Dwarf_Addr epc;
- int ret;
-
- ret = dwarf_haspc(sp_die, addr);
- if (ret <= 0)
- return false;
-
- if (offs) {
- ret = dwarf_entrypc(sp_die, &epc);
- DIE_IF(ret == -1);
- *offs = addr - epc;
- }
-
- return true;
-}
-
/* Get entry pc(or low pc, 1st entry of ranges) of the die */
static Dwarf_Addr die_get_entrypc(Dwarf_Die *dw_die)
{
@@ -208,70 +181,34 @@ static Dwarf_Addr die_get_entrypc(Dwarf_Die *dw_die)
return epc;
}

-/* Check if the abstract origin's address or not */
-static bool die_compare_abstract_origin(Dwarf_Die *in_die, void *origin_addr)
-{
- Dwarf_Attribute attr;
- Dwarf_Die origin;
-
- if (!dwarf_attr(in_die, DW_AT_abstract_origin, &attr))
- return false;
- if (!dwarf_formref_die(&attr, &origin))
- return false;
-
- return origin.addr == origin_addr;
-}
-
-/*
- * Search a Die from Die tree.
- * Note: cur_link->die should be deallocated in this function.
- */
-static int __search_die_tree(struct die_link *cur_link,
- int (*die_cb)(struct die_link *, void *),
- void *data)
+/* Get a variable die */
+static Dwarf_Die *die_find_variable(Dwarf_Die *sp_die, const char *name,
+ Dwarf_Die *die_mem)
{
- struct die_link new_link;
+ Dwarf_Die child_die;
+ int tag;
int ret;

- if (!die_cb)
- return 0;
-
- /* Check current die */
- while (!(ret = die_cb(cur_link, data))) {
- /* Check child die */
- ret = dwarf_child(&cur_link->die, &new_link.die);
- if (ret == 0) {
- new_link.parent = cur_link;
- ret = __search_die_tree(&new_link, die_cb, data);
- if (ret)
- break;
- }
+ ret = dwarf_child(sp_die, die_mem);
+ if (ret != 0)
+ return NULL;

- /* Move to next sibling */
- ret = dwarf_siblingof(&cur_link->die, &cur_link->die);
- if (ret != 0)
- return 0;
- }
- return ret;
-}
+ do {
+ tag = dwarf_tag(die_mem);
+ if ((tag == DW_TAG_formal_parameter ||
+ tag == DW_TAG_variable) &&
+ (die_compare_name(die_mem, name) == 0))
+ return die_mem;

-/* Search a die in its children's die tree */
-static int search_die_from_children(Dwarf_Die *parent_die,
- int (*die_cb)(struct die_link *, void *),
- void *data)
-{
- struct die_link new_link;
- int ret;
+ if (die_find_variable(die_mem, name, &child_die)) {
+ memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
+ return die_mem;
+ }
+ } while (dwarf_siblingof(die_mem, die_mem) == 0);

- new_link.parent = NULL;
- ret = dwarf_child(parent_die, &new_link.die);
- if (ret == 0)
- return __search_die_tree(&new_link, die_cb, data);
- else
- return 0;
+ return NULL;
}

-
/*
* Probe finder related functions
*/
@@ -347,28 +284,13 @@ error:
" Perhaps, it has been optimized out.", pf->var);
}

-static int variable_search_cb(struct die_link *dlink, void *data)
-{
- struct probe_finder *pf = (struct probe_finder *)data;
- int tag;
-
- tag = dwarf_tag(&dlink->die);
- DIE_IF(tag < 0);
- if ((tag == DW_TAG_formal_parameter ||
- tag == DW_TAG_variable) &&
- (die_compare_name(&dlink->die, pf->var) == 0)) {
- show_variable(&dlink->die, pf);
- return 1;
- }
- /* TODO: Support struct members and arrays */
- return 0;
-}
-
/* Find a variable in a subprogram die */
static void find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)
{
int ret;
+ Dwarf_Die vr_die;

+ /* TODO: Support struct members and arrays */
if (!is_c_varname(pf->var)) {
/* Output raw parameters */
ret = snprintf(pf->buf, pf->len, " %s", pf->var);
@@ -379,31 +301,42 @@ static void find_variable(Dwarf_Die *sp_die, struct probe_finder *pf)

pr_debug("Searching '%s' variable in context.\n", pf->var);
/* Search child die for local variables and parameters. */
- ret = search_die_from_children(sp_die, variable_search_cb, pf);
- if (!ret)
+ if (!die_find_variable(sp_die, pf->var, &vr_die))
die("Failed to find '%s' in this function.", pf->var);
+
+ show_variable(&vr_die, pf);
}

/* Show a probe point to output buffer */
-static void show_probe_point(Dwarf_Die *sp_die, size_t offs,
- struct probe_finder *pf)
+static void show_probe_point(Dwarf_Die *sp_die, struct probe_finder *pf)
{
struct probe_point *pp = pf->pp;
+ Dwarf_Addr eaddr;
+ Dwarf_Die die_mem;
const char *name;
char tmp[MAX_PROBE_BUFFER];
int ret, i, len;
Dwarf_Attribute fb_attr;
size_t nops;

+ /* If no real subprogram, find a real one */
+ if (!sp_die || dwarf_tag(sp_die) != DW_TAG_subprogram) {
+ sp_die = die_get_real_subprogram(&pf->cu_die,
+ pf->addr, &die_mem);
+ if (!sp_die)
+ die("Probe point is not found in subprograms.");
+ }
+
/* Output name of probe point */
name = dwarf_diename(sp_die);
if (name) {
- ret = snprintf(tmp, MAX_PROBE_BUFFER, "%s+%u", name,
- (unsigned int)offs);
+ dwarf_entrypc(sp_die, &eaddr);
+ ret = snprintf(tmp, MAX_PROBE_BUFFER, "%s+%lu", name,
+ (unsigned long)(pf->addr - eaddr));
/* Copy the function name if possible */
if (!pp->function) {
pp->function = strdup(name);
- pp->offset = offs;
+ pp->offset = (size_t)(pf->addr - eaddr);
}
} else {
/* This function has no name. */
@@ -450,10 +383,9 @@ static void find_probe_point_by_line(struct probe_finder *pf)
Dwarf_Lines *lines;
Dwarf_Line *line;
size_t nlines, i;
- Dwarf_Addr addr, epc;
+ Dwarf_Addr addr;
int lineno;
int ret;
- Dwarf_Die *sp_die, die_mem;

ret = dwarf_getsrclines(&pf->cu_die, &lines, &nlines);
DIE_IF(ret != 0);
@@ -474,77 +406,57 @@ static void find_probe_point_by_line(struct probe_finder *pf)
(int)i, lineno, (uintmax_t)addr);
pf->addr = addr;

- sp_die = die_get_real_subprogram(&pf->cu_die, addr, &die_mem);
- if (!sp_die)
- die("Probe point is not found in subprograms.");
- dwarf_entrypc(sp_die, &epc);
- show_probe_point(sp_die, (size_t)(addr - epc), pf);
+ show_probe_point(NULL, pf);
/* Continuing, because target line might be inlined. */
}
}

+static int probe_point_inline_cb(Dwarf_Die *in_die, void *data)
+{
+ struct probe_finder *pf = (struct probe_finder *)data;
+ struct probe_point *pp = pf->pp;
+
+ /* Get probe address */
+ pf->addr = die_get_entrypc(in_die);
+ pf->addr += pp->offset;
+ pr_debug("found inline addr: 0x%jx\n", (uintmax_t)pf->addr);
+
+ show_probe_point(in_die, pf);
+ return DWARF_CB_OK;
+}

/* Search function from function name */
-static int probe_point_search_cb(struct die_link *dlink, void *data)
+static int probe_point_search_cb(Dwarf_Die *sp_die, void *data)
{
struct probe_finder *pf = (struct probe_finder *)data;
struct probe_point *pp = pf->pp;
- struct die_link *lk;
- size_t offs;
- int tag;
- int ret;

- tag = dwarf_tag(&dlink->die);
- if (tag == DW_TAG_subprogram) {
- if (die_compare_name(&dlink->die, pp->function) == 0) {
- if (pp->line) { /* Function relative line */
- pf->fname = dwarf_decl_file(&dlink->die);
- dwarf_decl_line(&dlink->die, &pf->lno);
- pf->lno += pp->line;
- find_probe_point_by_line(pf);
- return 1;
- }
- if (dwarf_func_inline(&dlink->die)) {
- /* Inlined function, save it. */
- pf->origin = dlink->die.addr;
- return 0; /* Continue to search */
- }
- /* Get probe address */
- pf->addr = die_get_entrypc(&dlink->die);
- pf->addr += pp->offset;
- /* TODO: Check the address in this function */
- show_probe_point(&dlink->die, pp->offset, pf);
- return 1; /* Exit; no same symbol in this CU. */
- }
- } else if (tag == DW_TAG_inlined_subroutine && pf->origin) {
- if (die_compare_abstract_origin(&dlink->die, pf->origin)) {
- /* Get probe address */
- pf->addr = die_get_entrypc(&dlink->die);
- pf->addr += pp->offset;
- pr_debug("found inline addr: 0x%jx\n",
- (uintmax_t)pf->addr);
- /* Inlined function. Get a real subprogram */
- for (lk = dlink->parent; lk != NULL; lk = lk->parent) {
- tag = dwarf_tag(&lk->die);
- if (tag == DW_TAG_subprogram &&
- !dwarf_func_inline(&lk->die))
- goto found;
- }
- die("Failed to find real subprogram.");
-found:
- /* Get offset from subprogram */
- ret = die_within_subprogram(&lk->die, pf->addr, &offs);
- DIE_IF(!ret);
- show_probe_point(&lk->die, offs, pf);
- /* Continue to search */
- }
- }
- return 0;
+ /* Check tag and diename */
+ if (dwarf_tag(sp_die) != DW_TAG_subprogram ||
+ die_compare_name(sp_die, pp->function) != 0)
+ return 0;
+
+ if (pp->line) { /* Function relative line */
+ pf->fname = dwarf_decl_file(sp_die);
+ dwarf_decl_line(sp_die, &pf->lno);
+ pf->lno += pp->line;
+ find_probe_point_by_line(pf);
+ } else if (!dwarf_func_inline(sp_die)) {
+ /* Real function */
+ pf->addr = die_get_entrypc(sp_die);
+ pf->addr += pp->offset;
+ /* TODO: Check the address in this function */
+ show_probe_point(sp_die, pf);
+ } else
+ /* Inlined function: search instances */
+ dwarf_func_inline_instances(sp_die, probe_point_inline_cb, pf);
+
+ return 1; /* Exit; no same symbol in this CU. */
}

static void find_probe_point_by_func(struct probe_finder *pf)
{
- search_die_from_children(&pf->cu_die, probe_point_search_cb, pf);
+ dwarf_getfuncs(&pf->cu_die, probe_point_search_cb, pf, 0);
}

/* Find a probe point */
@@ -669,27 +581,25 @@ static void find_line_range_by_line(struct line_finder *lf)
}

/* Search function from function name */
-static int line_range_search_cb(struct die_link *dlink, void *data)
+static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
{
struct line_finder *lf = (struct line_finder *)data;
struct line_range *lr = lf->lr;
- int tag;
int ret;

- tag = dwarf_tag(&dlink->die);
- if (tag == DW_TAG_subprogram &&
- die_compare_name(&dlink->die, lr->function) == 0) {
+ if (dwarf_tag(sp_die) == DW_TAG_subprogram &&
+ die_compare_name(sp_die, lr->function) == 0) {
/* Get the address range of this function */
- ret = dwarf_highpc(&dlink->die, &lf->addr_e);
+ ret = dwarf_highpc(sp_die, &lf->addr_e);
if (ret == 0)
- ret = dwarf_lowpc(&dlink->die, &lf->addr_s);
+ ret = dwarf_lowpc(sp_die, &lf->addr_s);
if (ret != 0) {
lf->addr_s = 0;
lf->addr_e = 0;
}

- lf->fname = dwarf_decl_file(&dlink->die);
- dwarf_decl_line(&dlink->die, &lr->offset);
+ lf->fname = dwarf_decl_file(sp_die);
+ dwarf_decl_line(sp_die, &lr->offset);
pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
lf->lno_s = lr->offset + lr->start;
if (!lr->end)
@@ -706,7 +616,7 @@ static int line_range_search_cb(struct die_link *dlink, void *data)

static void find_line_range_by_func(struct line_finder *lf)
{
- search_die_from_children(&lf->cu_die, line_range_search_cb, lf);
+ dwarf_getfuncs(&lf->cu_die, line_range_search_cb, lf, 0);
}

int find_line_range(int fd, struct line_range *lr)
diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index 9dd4a88..74525ae 100644
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -66,7 +66,6 @@ struct probe_finder {
Dwarf_Addr addr; /* Address */
const char *fname; /* File name */
int lno; /* Line number */
- void *origin; /* Inline origin addr */
Dwarf_Die cu_die; /* Current CU */

/* For variable searching */

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