dbgcnt.def revision 1.1.1.1.8.2
1 1.1.1.1.8.2 tls /* This file contains the list of the debug counter for GCC. 2 1.1.1.1.8.2 tls Copyright (C) 2006, 2007, 2008 Free Software Foundation, Inc. 3 1.1.1.1.8.2 tls 4 1.1.1.1.8.2 tls This file is part of GCC. 5 1.1.1.1.8.2 tls 6 1.1.1.1.8.2 tls GCC is free software; you can redistribute it and/or modify it under 7 1.1.1.1.8.2 tls the terms of the GNU General Public License as published by the Free 8 1.1.1.1.8.2 tls Software Foundation; either version 3, or (at your option) any later 9 1.1.1.1.8.2 tls version. 10 1.1.1.1.8.2 tls 11 1.1.1.1.8.2 tls GCC is distributed in the hope that it will be useful, but WITHOUT ANY 12 1.1.1.1.8.2 tls WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 1.1.1.1.8.2 tls FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 1.1.1.1.8.2 tls for more details. 15 1.1.1.1.8.2 tls 16 1.1.1.1.8.2 tls You should have received a copy of the GNU General Public License 17 1.1.1.1.8.2 tls along with GCC; see the file COPYING3. If not see 18 1.1.1.1.8.2 tls <http://www.gnu.org/licenses/>. */ 19 1.1.1.1.8.2 tls 20 1.1.1.1.8.2 tls 21 1.1.1.1.8.2 tls /* A debug counter provides you a way to count an event 22 1.1.1.1.8.2 tls and return false after the counter has exceeded the threshold 23 1.1.1.1.8.2 tls specified by the option. 24 1.1.1.1.8.2 tls 25 1.1.1.1.8.2 tls What is it used for ? 26 1.1.1.1.8.2 tls 27 1.1.1.1.8.2 tls This is primarily used to speed up the search for the bad transformation 28 1.1.1.1.8.2 tls an optimization pass does. By doing a binary search on N, 29 1.1.1.1.8.2 tls you can quickly narrow down to one transformation 30 1.1.1.1.8.2 tls which is bad, or which triggers the bad behavior downstream 31 1.1.1.1.8.2 tls (usually in the form of the badly generated code). 32 1.1.1.1.8.2 tls 33 1.1.1.1.8.2 tls How does it work ? 34 1.1.1.1.8.2 tls 35 1.1.1.1.8.2 tls Every time dbg_cnt(named-counter) is called, 36 1.1.1.1.8.2 tls the counter is incremented for the named-counter. 37 1.1.1.1.8.2 tls And the incremented value is compared against the threshold (limit) 38 1.1.1.1.8.2 tls specified by the option. 39 1.1.1.1.8.2 tls dbg_cnt () returns true if it is at or below threshold, and false if above. 40 1.1.1.1.8.2 tls 41 1.1.1.1.8.2 tls How to add a new one ? 42 1.1.1.1.8.2 tls 43 1.1.1.1.8.2 tls To add a new counter, simply add an entry below with some descriptive name, 44 1.1.1.1.8.2 tls and add call(s) to dbg_cnt(your-counter-name) in appropriate places. 45 1.1.1.1.8.2 tls Usually, you want to control at the finest granularity 46 1.1.1.1.8.2 tls any particular transformation can happen. 47 1.1.1.1.8.2 tls e.g. for each instruction in a dead code elimination, 48 1.1.1.1.8.2 tls or for each copy instruction in register coalescing, 49 1.1.1.1.8.2 tls or constant-propagation for each insn, 50 1.1.1.1.8.2 tls or a block straightening, etc. 51 1.1.1.1.8.2 tls See dce.c for an example. With the dbg_cnt () call in dce.c, 52 1.1.1.1.8.2 tls now a developer can use -fdbg-cnt=dce:N 53 1.1.1.1.8.2 tls to stop doing the dead code elimination after N times. 54 1.1.1.1.8.2 tls 55 1.1.1.1.8.2 tls How to use it ? 56 1.1.1.1.8.2 tls 57 1.1.1.1.8.2 tls By default, all limits are UINT_MAX. 58 1.1.1.1.8.2 tls Since debug count is unsigned int, <= UINT_MAX returns true always. 59 1.1.1.1.8.2 tls i.e. dbg_cnt() returns true always regardless of the counter value 60 1.1.1.1.8.2 tls (although it still counts the event). 61 1.1.1.1.8.2 tls Use -fdbg-cnt=counter1:N,counter2:M,... 62 1.1.1.1.8.2 tls which sets the limit for counter1 to N, and the limit for counter2 to M, etc. 63 1.1.1.1.8.2 tls e.g. setting a limit to zero will make dbg_cnt () return false *always*. 64 1.1.1.1.8.2 tls 65 1.1.1.1.8.2 tls The following shell file can then be used to binary search for 66 1.1.1.1.8.2 tls exact transformation that causes the bug. A second shell script 67 1.1.1.1.8.2 tls should be written, say "tryTest", which exits with 1 if the 68 1.1.1.1.8.2 tls compiled program fails and exits with 0 if the program succeeds. 69 1.1.1.1.8.2 tls This shell script should take 1 parameter, the value to be passed 70 1.1.1.1.8.2 tls to set the counter of the compilation command in tryTest. Then, 71 1.1.1.1.8.2 tls assuming that the following script is called binarySearch, 72 1.1.1.1.8.2 tls the command: 73 1.1.1.1.8.2 tls 74 1.1.1.1.8.2 tls binarySearch tryTest 75 1.1.1.1.8.2 tls 76 1.1.1.1.8.2 tls will automatically find the highest value of the counter for which 77 1.1.1.1.8.2 tls the program fails. If tryTest never fails, binarySearch will 78 1.1.1.1.8.2 tls produce unpredictable results as it will try to find an upper bound 79 1.1.1.1.8.2 tls that does not exist. 80 1.1.1.1.8.2 tls 81 1.1.1.1.8.2 tls When dbgcnt does hits the limit, it writes a comment in the current 82 1.1.1.1.8.2 tls dump_file of the form: 83 1.1.1.1.8.2 tls 84 1.1.1.1.8.2 tls ***dbgcnt: limit reached for %s.*** 85 1.1.1.1.8.2 tls 86 1.1.1.1.8.2 tls Assuming that the dump file is logging the analysis/transformations 87 1.1.1.1.8.2 tls it is making, this pinpoints the exact position in the log file 88 1.1.1.1.8.2 tls where the problem transformation is being logged. 89 1.1.1.1.8.2 tls 90 1.1.1.1.8.2 tls ===================================== 91 1.1.1.1.8.2 tls #!/bin/bash 92 1.1.1.1.8.2 tls 93 1.1.1.1.8.2 tls while getopts "l:u:i:" opt 94 1.1.1.1.8.2 tls do 95 1.1.1.1.8.2 tls case $opt in 96 1.1.1.1.8.2 tls l) lb="$OPTARG";; 97 1.1.1.1.8.2 tls u) ub="$OPTARG";; 98 1.1.1.1.8.2 tls i) init="$OPTARG";; 99 1.1.1.1.8.2 tls ?) usage; exit 3;; 100 1.1.1.1.8.2 tls esac 101 1.1.1.1.8.2 tls done 102 1.1.1.1.8.2 tls 103 1.1.1.1.8.2 tls shift $(($OPTIND - 1)) 104 1.1.1.1.8.2 tls echo $@ 105 1.1.1.1.8.2 tls cmd=${1+"${@}"} 106 1.1.1.1.8.2 tls 107 1.1.1.1.8.2 tls lb=${lb:=0} 108 1.1.1.1.8.2 tls init=${init:=100} 109 1.1.1.1.8.2 tls 110 1.1.1.1.8.2 tls $cmd $lb 111 1.1.1.1.8.2 tls lb_val=$? 112 1.1.1.1.8.2 tls if [ -z "$ub" ]; then 113 1.1.1.1.8.2 tls # find the upper bound 114 1.1.1.1.8.2 tls ub=$(($init + $lb)) 115 1.1.1.1.8.2 tls true 116 1.1.1.1.8.2 tls while [ $? -eq $lb_val ]; do 117 1.1.1.1.8.2 tls ub=$(($ub * 10)) 118 1.1.1.1.8.2 tls #ub=`expr $ub \* 10` 119 1.1.1.1.8.2 tls $cmd $ub 120 1.1.1.1.8.2 tls done 121 1.1.1.1.8.2 tls fi 122 1.1.1.1.8.2 tls 123 1.1.1.1.8.2 tls echo command: $cmd 124 1.1.1.1.8.2 tls 125 1.1.1.1.8.2 tls true 126 1.1.1.1.8.2 tls while [ `expr $ub - $lb` -gt 1 ]; do 127 1.1.1.1.8.2 tls try=$(($lb + ( $ub - $lb ) / 2)) 128 1.1.1.1.8.2 tls $cmd $try 129 1.1.1.1.8.2 tls if [ $? -eq $lb_val ]; then 130 1.1.1.1.8.2 tls lb=$try 131 1.1.1.1.8.2 tls else 132 1.1.1.1.8.2 tls ub=$try 133 1.1.1.1.8.2 tls fi 134 1.1.1.1.8.2 tls done 135 1.1.1.1.8.2 tls 136 1.1.1.1.8.2 tls echo lbound: $lb 137 1.1.1.1.8.2 tls echo ubound: $ub 138 1.1.1.1.8.2 tls 139 1.1.1.1.8.2 tls ===================================== 140 1.1.1.1.8.2 tls 141 1.1.1.1.8.2 tls */ 142 1.1.1.1.8.2 tls 143 1.1.1.1.8.2 tls /* Debug counter definitions. */ 144 1.1.1.1.8.2 tls DEBUG_COUNTER (auto_inc_dec) 145 1.1.1.1.8.2 tls DEBUG_COUNTER (ccp) 146 1.1.1.1.8.2 tls DEBUG_COUNTER (cfg_cleanup) 147 1.1.1.1.8.2 tls DEBUG_COUNTER (cse2_move2add) 148 1.1.1.1.8.2 tls DEBUG_COUNTER (cprop) 149 1.1.1.1.8.2 tls DEBUG_COUNTER (dce) 150 1.1.1.1.8.2 tls DEBUG_COUNTER (dce_fast) 151 1.1.1.1.8.2 tls DEBUG_COUNTER (dce_ud) 152 1.1.1.1.8.2 tls DEBUG_COUNTER (delete_trivial_dead) 153 1.1.1.1.8.2 tls DEBUG_COUNTER (df_byte_scan) 154 1.1.1.1.8.2 tls DEBUG_COUNTER (dse) 155 1.1.1.1.8.2 tls DEBUG_COUNTER (dse1) 156 1.1.1.1.8.2 tls DEBUG_COUNTER (dse2) 157 1.1.1.1.8.2 tls DEBUG_COUNTER (gcse2_delete) 158 1.1.1.1.8.2 tls DEBUG_COUNTER (global_alloc_at_func) 159 1.1.1.1.8.2 tls DEBUG_COUNTER (global_alloc_at_reg) 160 1.1.1.1.8.2 tls DEBUG_COUNTER (hoist) 161 1.1.1.1.8.2 tls DEBUG_COUNTER (ia64_sched2) 162 1.1.1.1.8.2 tls DEBUG_COUNTER (if_conversion) 163 1.1.1.1.8.2 tls DEBUG_COUNTER (if_after_combine) 164 1.1.1.1.8.2 tls DEBUG_COUNTER (if_after_reload) 165 1.1.1.1.8.2 tls DEBUG_COUNTER (local_alloc_for_sched) 166 1.1.1.1.8.2 tls DEBUG_COUNTER (postreload_cse) 167 1.1.1.1.8.2 tls DEBUG_COUNTER (pre) 168 1.1.1.1.8.2 tls DEBUG_COUNTER (pre_insn) 169 1.1.1.1.8.2 tls DEBUG_COUNTER (treepre_insert) 170 1.1.1.1.8.2 tls DEBUG_COUNTER (sched2_func) 171 1.1.1.1.8.2 tls DEBUG_COUNTER (sched_block) 172 1.1.1.1.8.2 tls DEBUG_COUNTER (sched_func) 173 1.1.1.1.8.2 tls DEBUG_COUNTER (sched_insn) 174 1.1.1.1.8.2 tls DEBUG_COUNTER (sched_region) 175 1.1.1.1.8.2 tls DEBUG_COUNTER (sel_sched_cnt) 176 1.1.1.1.8.2 tls DEBUG_COUNTER (sel_sched_region_cnt) 177 1.1.1.1.8.2 tls DEBUG_COUNTER (sel_sched_insn_cnt) 178 1.1.1.1.8.2 tls DEBUG_COUNTER (sms_sched_loop) 179 1.1.1.1.8.2 tls DEBUG_COUNTER (store_motion) 180 1.1.1.1.8.2 tls DEBUG_COUNTER (split_for_sched2) 181 1.1.1.1.8.2 tls DEBUG_COUNTER (tail_call) 182
Indexes created Tue Mar 31 00:22:50 UTC 2026