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Subject[PATCH 4.18 093/168] perf annotate: Fix parsing aarch64 branch instructions after objdump update
Date
4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Kim Phillips <kim.phillips@arm.com>

[ Upstream commit 4e67b2a5df5d3f341776d12ee575e00ca3ef92de ]

Starting with binutils 2.28, aarch64 objdump adds comments to the
disassembly output to show the alternative names of a condition code
[1].

It is assumed that commas in objdump comments could occur in other
arches now or in the future, so this fix is arch-independent.

The fix could have been done with arm64 specific jump__parse and
jump__scnprintf functions, but the jump__scnprintf instruction would
have to have its comment character be a literal, since the scnprintf
functions cannot receive a struct arch easily.

This inconvenience also applies to the generic jump__scnprintf, which is
why we add a raw_comment pointer to struct ins_operands, so the __parse
function assigns it to be re-used by its corresponding __scnprintf
function.

Example differences in 'perf annotate --stdio2' output on an aarch64
perf.data file:

BEFORE: → b.cs ffff200008133d1c <unwind_frame+0x18c> // b.hs, dffff7ecc47b
AFTER : ↓ b.cs 18c

BEFORE: → b.cc ffff200008d8d9cc <get_alloc_profile+0x31c> // b.lo, b.ul, dffff727295b
AFTER : ↓ b.cc 31c

The branch target labels 18c and 31c also now appear in the output:

BEFORE: add x26, x29, #0x80
AFTER : 18c: add x26, x29, #0x80

BEFORE: add x21, x21, #0x8
AFTER : 31c: add x21, x21, #0x8

The Fixes: tag below is added so stable branches will get the update; it
doesn't necessarily mean that commit was broken at the time, rather it
didn't withstand the aarch64 objdump update.

Tested no difference in output for sample x86_64, power arch perf.data files.

[1] https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commit;h=bb7eff5206e4795ac79c177a80fe9f4630aaf730

Signed-off-by: Kim Phillips <kim.phillips@arm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Taeung Song <treeze.taeung@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
Fixes: b13bbeee5ee6 ("perf annotate: Fix branch instruction with multiple operands")
Link: http://lkml.kernel.org/r/20180827125340.a2f7e291901d17cea05daba4@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
tools/perf/util/annotate.c | 22 +++++++++++++++++++++-
tools/perf/util/annotate.h | 1 +
2 files changed, 22 insertions(+), 1 deletion(-)

--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -281,7 +281,19 @@ bool ins__is_call(const struct ins *ins)
return ins->ops == &call_ops || ins->ops == &s390_call_ops;
}

-static int jump__parse(struct arch *arch __maybe_unused, struct ins_operands *ops, struct map_symbol *ms)
+/*
+ * Prevents from matching commas in the comment section, e.g.:
+ * ffff200008446e70: b.cs ffff2000084470f4 <generic_exec_single+0x314> // b.hs, b.nlast
+ */
+static inline const char *validate_comma(const char *c, struct ins_operands *ops)
+{
+ if (ops->raw_comment && c > ops->raw_comment)
+ return NULL;
+
+ return c;
+}
+
+static int jump__parse(struct arch *arch, struct ins_operands *ops, struct map_symbol *ms)
{
struct map *map = ms->map;
struct symbol *sym = ms->sym;
@@ -290,6 +302,10 @@ static int jump__parse(struct arch *arch
};
const char *c = strchr(ops->raw, ',');
u64 start, end;
+
+ ops->raw_comment = strchr(ops->raw, arch->objdump.comment_char);
+ c = validate_comma(c, ops);
+
/*
* Examples of lines to parse for the _cpp_lex_token@@Base
* function:
@@ -309,6 +325,7 @@ static int jump__parse(struct arch *arch
ops->target.addr = strtoull(c, NULL, 16);
if (!ops->target.addr) {
c = strchr(c, ',');
+ c = validate_comma(c, ops);
if (c++ != NULL)
ops->target.addr = strtoull(c, NULL, 16);
}
@@ -366,9 +383,12 @@ static int jump__scnprintf(struct ins *i
return scnprintf(bf, size, "%-6s %s", ins->name, ops->target.sym->name);

c = strchr(ops->raw, ',');
+ c = validate_comma(c, ops);
+
if (c != NULL) {
const char *c2 = strchr(c + 1, ',');

+ c2 = validate_comma(c2, ops);
/* check for 3-op insn */
if (c2 != NULL)
c = c2;
--- a/tools/perf/util/annotate.h
+++ b/tools/perf/util/annotate.h
@@ -21,6 +21,7 @@ struct ins {

struct ins_operands {
char *raw;
+ char *raw_comment;
struct {
char *raw;
char *name;

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