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
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
|
# Copyright 2023-2024 Free Software Foundation, Inc.
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
# Load the GDB executable, and then 'save gdb-index', and make some
# checks of the generated index file.
load_lib selftest-support.exp
# Can't save an index with readnow.
require !readnow
# A multiplier used to ensure slow tasks are less likely to timeout.
set timeout_factor 20
set filename [selftest_prepare]
if { $filename eq "" } {
unsupported "${gdb_test_file_name}.exp"
return -1
}
with_timeout_factor $timeout_factor {
# Start GDB, load FILENAME.
clean_restart $filename
}
# Record how many worker threads GDB is using.
set worker_threads [gdb_get_worker_threads]
if { $worker_threads eq "UNKNOWN" } {
unresolved "unable to get worker thread count"
return -1
}
# Generate an index file.
set dir1 [standard_output_file "index_1"]
remote_exec host "mkdir -p ${dir1}"
with_timeout_factor $timeout_factor {
gdb_test_no_output "save gdb-index $dir1" \
"create gdb-index file"
gdb_test_no_output "save gdb-index -dwarf-5 $dir1" \
"create dwarf-index files"
}
# Close GDB.
gdb_exit
# Validate that the index-file FILENAME has made efficient use of its
# symbol hash table. Calculate the number of symbols in the hash
# table and the total hash table size. The hash table starts with
# 1024 entries, and then doubles each time it is filled to 75%. At
# 75% filled, doubling the size takes it to 37.5% filled.
#
# Thus, the hash table is correctly filled if:
# 1. Its size is 1024 (i.e. it has not yet had its first doubling), or
# 2. Its filled percentage is over 37%
#
# We could check that it is not over filled, but I don't as that's not
# really an issue. But we did once have a bug where the table was
# doubled incorrectly, in which case we'd see a filled percentage of
# around 2% in some cases, which is a huge waste of disk space.
proc check_symbol_table_usage { filename } {
# Open the file in binary mode and read-only mode.
set fp [open $filename rb]
# Configure the channel to use binary translation.
fconfigure $fp -translation binary
# Read the first 8 bytes of the file, which contain the header of
# the index section.
set header [read $fp [expr 7 * 4]]
# Scan the header to get the version, the CU list offset, and the
# types CU list offset.
binary scan $header iiiiii version \
_ _ _ symbol_table_offset shortcut_offset
# The length of the symbol hash table (in entries).
set len [expr ($shortcut_offset - $symbol_table_offset) / 8]
# Now walk the hash table and count how many entries are in use.
set offset $symbol_table_offset
set count 0
while { $offset < $shortcut_offset } {
seek $fp $offset
set entry [read $fp 8]
binary scan $entry ii name_ptr flags
if { $name_ptr != 0 } {
incr count
}
incr offset 8
}
# Close the file.
close $fp
# Calculate how full the cache is.
set pct [expr (100 * double($count)) / $len]
# Write our results out to the gdb.log.
verbose -log "Hash table size: $len"
verbose -log "Hash table entries: $count"
verbose -log "Percentage usage: $pct%"
# The minimum fill percentage is actually 37.5%, but we give TCL a
# little flexibility in case the FP maths give a result a little
# off.
gdb_assert { $len == 1024 || $pct > 37 } \
"symbol hash table usage"
}
set index_filename_base [file tail $filename]
check_symbol_table_usage "$dir1/${index_filename_base}.gdb-index"
# If GDB is using more than 1 worker thread then reduce the number of
# worker threads, regenerate the index, and check that we get the same
# index file back. At one point the layout of the index would vary
# based on the number of worker threads used.
if { $worker_threads > 1 } {
# Start GDB, but don't load a file yet.
clean_restart
# Adjust the number of threads to use.
set reduced_threads [expr $worker_threads / 2]
gdb_test_no_output "maint set worker-threads $reduced_threads"
with_timeout_factor $timeout_factor {
# Now load the test binary.
gdb_file_cmd $filename
}
# Generate an index file.
set dir2 [standard_output_file "index_2"]
remote_exec host "mkdir -p ${dir2}"
with_timeout_factor $timeout_factor {
gdb_test_no_output "save gdb-index $dir2" \
"create second gdb-index file"
gdb_test_no_output "save gdb-index -dwarf-5 $dir2" \
"create second dwarf-index files"
}
# Close GDB.
gdb_exit
# Now check that the index files are identical.
foreach suffix { gdb-index debug_names debug_str } {
set result \
[remote_exec host \
"cmp -s \"$dir1/${index_filename_base}.${suffix}\" \"$dir2/${index_filename_base}.${suffix}\""]
gdb_assert { [lindex $result 0] == 0 } \
"$suffix files are identical"
}
}
|
