LKML Archive on lore.kernel.org
 help / color / Atom feed
From: Masami Hiramatsu <mhiramat@kernel.org>
To: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	linux-kernel@vger.kernel.org
Subject: [BUGFIX PATCH 3/3] perf/probe: Fix to show function entry line as probe-able
Date: Thu, 24 Oct 2019 18:12:54 +0900
Message-ID: <157190837419.1859.4619125803596816752.stgit@devnote2> (raw)
In-Reply-To: <157190834681.1859.7399361844806238387.stgit@devnote2>

Fix die_walk_lines() to list the function entry line correctly.
Since the dwarf_entrypc() does not return the entry pc if the DIE
has only range attribute, __die_walk_funclines() fails to list
the declaration line (entry line) in that case.

To solve this issue, this introduces die_entrypc() which correctly
returns the entry PC (the first address range) even if the DIE has
only range attribute. With this fix die_walk_lines() shows the
function entry line is able to probe correctly.

Fixes: 4cc9cec636e7 ("perf probe: Introduce lines walker interface")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 tools/perf/util/dwarf-aux.c |   24 +++++++++++++++++++++++-
 tools/perf/util/dwarf-aux.h |    3 +++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
index 929b7c0567f4..063f71da6b63 100644
--- a/tools/perf/util/dwarf-aux.c
+++ b/tools/perf/util/dwarf-aux.c
@@ -307,6 +307,28 @@ bool die_is_func_def(Dwarf_Die *dw_die)
 		dwarf_attr(dw_die, DW_AT_declaration, &attr) == NULL);
 }
 
+/**
+ * die_entrypc - Returns entry PC (the lowest address) of a DIE
+ * @dw_die: a DIE
+ * @addr: where to store entry PC
+ *
+ * Since dwarf_entrypc() does not return entry PC if the DIE has only address
+ * range, we have to use this to retrieve the lowest address from the address
+ * range attribute.
+ */
+int die_entrypc(Dwarf_Die *dw_die, Dwarf_Addr *addr)
+{
+	Dwarf_Addr base, end;
+
+	if (!addr)
+		return -EINVAL;
+
+	if (dwarf_entrypc(dw_die, addr) == 0)
+		return 0;
+
+	return dwarf_ranges(dw_die, 0, &base, addr, &end) < 0 ? -ENOENT : 0;
+}
+
 /**
  * die_is_func_instance - Ensure that this DIE is an instance of a subprogram
  * @dw_die: a DIE
@@ -713,7 +735,7 @@ static int __die_walk_funclines(Dwarf_Die *sp_die, bool recursive,
 	/* Handle function declaration line */
 	fname = dwarf_decl_file(sp_die);
 	if (fname && dwarf_decl_line(sp_die, &lineno) == 0 &&
-	    dwarf_entrypc(sp_die, &addr) == 0) {
+	    die_entrypc(sp_die, &addr) == 0) {
 		lw.retval = callback(fname, lineno, addr, data);
 		if (lw.retval != 0)
 			goto done;
diff --git a/tools/perf/util/dwarf-aux.h b/tools/perf/util/dwarf-aux.h
index f204e5892403..506006e0cf66 100644
--- a/tools/perf/util/dwarf-aux.h
+++ b/tools/perf/util/dwarf-aux.h
@@ -29,6 +29,9 @@ int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr,
 /* Get DW_AT_linkage_name (should be NULL for C binary) */
 const char *die_get_linkage_name(Dwarf_Die *dw_die);
 
+/* Get the lowest PC in DIE (including range list) */
+int die_entrypc(Dwarf_Die *dw_die, Dwarf_Addr *addr);
+
 /* Ensure that this DIE is a subprogram and definition (not declaration) */
 bool die_is_func_def(Dwarf_Die *dw_die);
 


  parent reply index

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-24  9:12 [BUGFIX PATCH 0/3] perf/probe: Fix available line bugs Masami Hiramatsu
2019-10-24  9:12 ` [BUGFIX PATCH 1/3] perf/probe: Fix to find range-only function instance Masami Hiramatsu
2019-11-12 11:18   ` [tip: perf/core] perf probe: " tip-bot2 for Masami Hiramatsu
2019-10-24  9:12 ` [BUGFIX PATCH 2/3] perf/probe: Walk function lines in lexical blocks Masami Hiramatsu
2019-11-12 11:18   ` [tip: perf/core] perf probe: " tip-bot2 for Masami Hiramatsu
2019-10-24  9:12 ` Masami Hiramatsu [this message]
2019-11-12 11:18   ` [tip: perf/core] perf probe: Fix to show function entry line as probe-able tip-bot2 for Masami Hiramatsu
2019-10-24 13:43 ` [BUGFIX PATCH 0/3] perf/probe: Fix available line bugs Arnaldo Carvalho de Melo
2019-10-24 15:36   ` Masami Hiramatsu
2019-10-24 20:23     ` Arnaldo Carvalho de Melo
2019-10-24 23:22       ` Masami Hiramatsu

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=157190837419.1859.4619125803596816752.stgit@devnote2 \
    --to=mhiramat@kernel.org \
    --cc=acme@kernel.org \
    --cc=jolsa@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=namhyung@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git
	git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git