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    Subject[PATCH -tip v3 7/9] perf probe: Check function address range strictly in line finder
    Date
    Check (inlined) function address range strictly for
    improving output of probe-able lines of inline functions.

    Without this change, perf probe --line <function> sometimes
    showed other inline function bodies too, because it didn't
    filter out inlined functions.

    Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
    Cc: Ingo Molnar <mingo@elte.hu>
    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>
    ---

    tools/perf/util/probe-finder.c | 74 +++++++++++++++++++++++++++++-----------
    tools/perf/util/probe-finder.h | 2 -
    2 files changed, 53 insertions(+), 23 deletions(-)

    diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
    index 6305f34..a410356 100644
    --- a/tools/perf/util/probe-finder.c
    +++ b/tools/perf/util/probe-finder.c
    @@ -161,6 +161,31 @@ static Dwarf_Die *die_get_real_subprogram(Dwarf_Die *cu_die, Dwarf_Addr addr,
    return die_mem;
    }

    +/* Similar to dwarf_getfuncs, but returns inlined_subroutine if exists. */
    +static Dwarf_Die *die_get_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
    + Dwarf_Die *die_mem)
    +{
    + Dwarf_Die child_die;
    + int ret;
    +
    + ret = dwarf_child(sp_die, die_mem);
    + if (ret != 0)
    + return NULL;
    +
    + do {
    + if (dwarf_tag(die_mem) == DW_TAG_inlined_subroutine &&
    + dwarf_haspc(die_mem, addr))
    + return die_mem;
    +
    + if (die_get_inlinefunc(die_mem, addr, &child_die)) {
    + memcpy(die_mem, &child_die, sizeof(Dwarf_Die));
    + return die_mem;
    + }
    + } while (dwarf_siblingof(die_mem, die_mem) == 0);
    +
    + return NULL;
    +}
    +
    /* Compare diename and tname */
    static bool die_compare_name(Dwarf_Die *dw_die, const char *tname)
    {
    @@ -534,7 +559,7 @@ found:
    }

    /* Find line range from its line number */
    -static void find_line_range_by_line(struct line_finder *lf)
    +static void find_line_range_by_line(Dwarf_Die *sp_die, struct line_finder *lf)
    {
    Dwarf_Lines *lines;
    Dwarf_Line *line;
    @@ -543,6 +568,7 @@ static void find_line_range_by_line(struct line_finder *lf)
    int lineno;
    int ret;
    const char *src;
    + Dwarf_Die die_mem;

    INIT_LIST_HEAD(&lf->lr->line_list);
    ret = dwarf_getsrclines(&lf->cu_die, &lines, &nlines);
    @@ -550,22 +576,28 @@ static void find_line_range_by_line(struct line_finder *lf)

    for (i = 0; i < nlines; i++) {
    line = dwarf_onesrcline(lines, i);
    - dwarf_lineno(line, &lineno);
    + ret = dwarf_lineno(line, &lineno);
    + DIE_IF(ret != 0);
    if (lf->lno_s > lineno || lf->lno_e < lineno)
    continue;

    + if (sp_die) {
    + /* Address filtering 1: does sp_die include addr? */
    + ret = dwarf_lineaddr(line, &addr);
    + DIE_IF(ret != 0);
    + if (!dwarf_haspc(sp_die, addr))
    + continue;
    +
    + /* Address filtering 2: No child include addr? */
    + if (die_get_inlinefunc(sp_die, addr, &die_mem))
    + continue;
    + }
    +
    /* TODO: Get fileno from line, but how? */
    src = dwarf_linesrc(line, NULL, NULL);
    if (strtailcmp(src, lf->fname) != 0)
    continue;

    - /* Filter line in the function address range */
    - if (lf->addr_s && lf->addr_e) {
    - ret = dwarf_lineaddr(line, &addr);
    - DIE_IF(ret != 0);
    - if (lf->addr_s > addr || lf->addr_e <= addr)
    - continue;
    - }
    /* Copy real path */
    if (!lf->lr->path)
    lf->lr->path = strdup(src);
    @@ -580,24 +612,20 @@ static void find_line_range_by_line(struct line_finder *lf)
    }
    }

    +static int line_range_inline_cb(Dwarf_Die *in_die, void *data)
    +{
    + find_line_range_by_line(in_die, (struct line_finder *)data);
    + return DWARF_CB_ABORT; /* No need to find other instances */
    +}
    +
    /* Search function from function name */
    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 ret;

    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(sp_die, &lf->addr_e);
    - if (ret == 0)
    - ret = dwarf_lowpc(sp_die, &lf->addr_s);
    - if (ret != 0) {
    - lf->addr_s = 0;
    - lf->addr_e = 0;
    - }
    -
    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);
    @@ -608,7 +636,11 @@ static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
    lf->lno_e = lr->offset + lr->end;
    lr->start = lf->lno_s;
    lr->end = lf->lno_e;
    - find_line_range_by_line(lf);
    + if (dwarf_func_inline(sp_die))
    + dwarf_func_inline_instances(sp_die,
    + line_range_inline_cb, lf);
    + else
    + find_line_range_by_line(sp_die, lf);
    return 1;
    }
    return 0;
    @@ -660,7 +692,7 @@ int find_line_range(int fd, struct line_range *lr)
    lf.lno_e = INT_MAX;
    else
    lf.lno_e = lr->end;
    - find_line_range_by_line(&lf);
    + find_line_range_by_line(NULL, &lf);
    }
    }
    off = noff;
    diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
    index 74525ae..75a660d 100644
    --- a/tools/perf/util/probe-finder.h
    +++ b/tools/perf/util/probe-finder.h
    @@ -82,8 +82,6 @@ struct line_finder {
    const char *fname; /* File name */
    int lno_s; /* Start line number */
    int lno_e; /* End line number */
    - Dwarf_Addr addr_s; /* Start address */
    - Dwarf_Addr addr_e; /* End address */
    Dwarf_Die cu_die; /* Current CU */
    int found;
    };

    --
    Masami Hiramatsu

    Software Engineer
    Hitachi Computer Products (America), Inc.
    Software Solutions Division

    e-mail: mhiramat@redhat.com


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