1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
|
#!/usr/bin/env python3
"""
This script reads the input from stdin, extracts all lines starting with
"# FDATA: " (or a given prefix instead of "FDATA"), parses the directives,
replaces symbol names ("#name#") with either symbol values or with offsets from
respective anchor symbols, and prints the resulting file to stdout.
"""
import argparse
import subprocess
import sys
import re
parser = argparse.ArgumentParser()
parser.add_argument("input")
parser.add_argument("objfile", help="Object file to extract symbol values from")
parser.add_argument("output")
parser.add_argument("prefix", nargs="?", default="FDATA", help="Custom FDATA prefix")
parser.add_argument("--nmtool", default="nm", help="Path to nm tool")
parser.add_argument("--no-lbr", action="store_true")
args = parser.parse_args()
# Regexes to extract FDATA lines from input and parse FDATA and pre-aggregated
# profile data
prefix_pat = re.compile(f"^# {args.prefix}: (.*)")
# FDATA records:
# <is symbol?> <closest elf symbol or DSO name> <relative FROM address>
# <is symbol?> <closest elf symbol or DSO name> <relative TO address>
# <number of mispredictions> <number of branches>
fdata_pat = re.compile(r"([01].*) (?P<exec>\d+) (?P<mispred>\d+)")
# Pre-aggregated profile:
# {B|F|f} [<start_id>:]<start_offset> [<end_id>:]<end_offset> <count>
# [<mispred_count>]
preagg_pat = re.compile(r"(?P<type>[BFf]) (?P<offsets_count>.*)")
# No-LBR profile:
# <is symbol?> <closest elf symbol or DSO name> <relative address> <count>
nolbr_pat = re.compile(r"([01].*) (?P<count>\d+)")
# Replacement symbol: #symname#
replace_pat = re.compile(r"#(?P<symname>[^#]+)#")
# Read input and construct the representation of fdata expressions
# as (src_tuple, dst_tuple, mispred_count, exec_count) tuples, where src and dst
# are represented as (is_sym, anchor, offset) tuples
exprs = []
with open(args.input, "r") as f:
for line in f.readlines():
prefix_match = prefix_pat.match(line)
if not prefix_match:
continue
profile_line = prefix_match.group(1)
fdata_match = fdata_pat.match(profile_line)
preagg_match = preagg_pat.match(profile_line)
nolbr_match = nolbr_pat.match(profile_line)
if fdata_match:
src_dst, execnt, mispred = fdata_match.groups()
# Split by whitespaces not preceded by a backslash (negative lookbehind)
chunks = re.split(r"(?<!\\) +", src_dst)
# Check if the number of records separated by non-escaped whitespace
# exactly matches the format.
assert (
len(chunks) == 6
), f"ERROR: wrong format/whitespaces must be escaped:\n{line}"
exprs.append(("FDATA", (*chunks, execnt, mispred)))
elif nolbr_match:
loc, count = nolbr_match.groups()
# Split by whitespaces not preceded by a backslash (negative lookbehind)
chunks = re.split(r"(?<!\\) +", loc)
# Check if the number of records separated by non-escaped whitespace
# exactly matches the format.
assert (
len(chunks) == 3
), f"ERROR: wrong format/whitespaces must be escaped:\n{line}"
exprs.append(("NOLBR", (*chunks, count)))
elif preagg_match:
exprs.append(("PREAGG", preagg_match.groups()))
else:
exit("ERROR: unexpected input:\n%s" % line)
# Read nm output: <symbol value> <symbol type> <symbol name>
nm_output = subprocess.run(
[args.nmtool, "--defined-only", args.objfile], text=True, capture_output=True
).stdout
# Populate symbol map
symbols = {}
for symline in nm_output.splitlines():
symval, _, symname = symline.split(maxsplit=2)
symbols[symname] = symval
def evaluate_symbol(issym, anchor, offsym):
sym_match = replace_pat.match(offsym)
if not sym_match:
# No need to evaluate symbol value, return as is
return f"{issym} {anchor} {offsym}"
symname = sym_match.group("symname")
assert symname in symbols, f"ERROR: symbol {symname} is not defined in binary"
# Evaluate to an absolute offset if issym is false
if issym == "0":
return f"{issym} {anchor} {symbols[symname]}"
# Evaluate symbol against its anchor if issym is true
assert anchor in symbols, f"ERROR: symbol {anchor} is not defined in binary"
anchor_value = int(symbols[anchor], 16)
symbol_value = int(symbols[symname], 16)
sym_offset = symbol_value - anchor_value
return f'{issym} {anchor} {format(sym_offset, "x")}'
def replace_symbol(matchobj):
"""
Expects matchobj to only capture one group which contains the symbol name.
"""
symname = matchobj.group("symname")
assert symname in symbols, f"ERROR: symbol {symname} is not defined in binary"
return symbols[symname]
with open(args.output, "w", newline="\n") as f:
if args.no_lbr:
print("no_lbr", file=f)
for etype, expr in exprs:
if etype == "FDATA":
issym1, anchor1, offsym1, issym2, anchor2, offsym2, execnt, mispred = expr
print(
evaluate_symbol(issym1, anchor1, offsym1),
evaluate_symbol(issym2, anchor2, offsym2),
execnt,
mispred,
file=f,
)
elif etype == "NOLBR":
issym, anchor, offsym, count = expr
print(evaluate_symbol(issym, anchor, offsym), count, file=f)
elif etype == "PREAGG":
# Replace all symbols enclosed in ##
print(expr[0], re.sub(replace_pat, replace_symbol, expr[1]), file=f)
else:
exit("ERROR: unhandled expression type:\n%s" % etype)
|
