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- /* This file contains the list of the debug counter for GCC.
- Copyright (C) 2006-2015 Free Software Foundation, Inc.
- This file is part of GCC.
- GCC 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, or (at your option) any later
- version.
- GCC 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 GCC; see the file COPYING3. If not see
- <http://www.gnu.org/licenses/>. */
- /* A debug counter provides you a way to count an event
- and return false after the counter has exceeded the threshold
- specified by the option.
- What is it used for ?
- This is primarily used to speed up the search for the bad transformation
- an optimization pass does. By doing a binary search on N,
- you can quickly narrow down to one transformation
- which is bad, or which triggers the bad behavior downstream
- (usually in the form of the badly generated code).
- How does it work ?
- Every time dbg_cnt(named-counter) is called,
- the counter is incremented for the named-counter.
- And the incremented value is compared against the threshold (limit)
- specified by the option.
- dbg_cnt () returns true if it is at or below threshold, and false if above.
- How to add a new one ?
- To add a new counter, simply add an entry below with some descriptive name,
- and add call(s) to dbg_cnt(your-counter-name) in appropriate places.
- Usually, you want to control at the finest granularity
- any particular transformation can happen.
- e.g. for each instruction in a dead code elimination,
- or for each copy instruction in register coalescing,
- or constant-propagation for each insn,
- or a block straightening, etc.
- See dce.c for an example. With the dbg_cnt () call in dce.c,
- now a developer can use -fdbg-cnt=dce:N
- to stop doing the dead code elimination after N times.
- How to use it ?
- By default, all limits are UINT_MAX.
- Since debug count is unsigned int, <= UINT_MAX returns true always.
- i.e. dbg_cnt() returns true always regardless of the counter value
- (although it still counts the event).
- Use -fdbg-cnt=counter1:N,counter2:M,...
- which sets the limit for counter1 to N, and the limit for counter2 to M, etc.
- e.g. setting a limit to zero will make dbg_cnt () return false *always*.
- The following shell file can then be used to binary search for
- exact transformation that causes the bug. A second shell script
- should be written, say "tryTest", which exits with 1 if the
- compiled program fails and exits with 0 if the program succeeds.
- This shell script should take 1 parameter, the value to be passed
- to set the counter of the compilation command in tryTest. Then,
- assuming that the following script is called binarySearch,
- the command:
- binarySearch tryTest
- will automatically find the highest value of the counter for which
- the program fails. If tryTest never fails, binarySearch will
- produce unpredictable results as it will try to find an upper bound
- that does not exist.
- When dbgcnt does hits the limit, it writes a comment in the current
- dump_file of the form:
- ***dbgcnt: limit reached for %s.***
- Assuming that the dump file is logging the analysis/transformations
- it is making, this pinpoints the exact position in the log file
- where the problem transformation is being logged.
- =====================================
- #!/bin/bash
- while getopts "l:u:i:" opt
- do
- case $opt in
- l) lb="$OPTARG";;
- u) ub="$OPTARG";;
- i) init="$OPTARG";;
- ?) usage; exit 3;;
- esac
- done
- shift $(($OPTIND - 1))
- echo $@
- cmd=${1+"${@}"}
- lb=${lb:=0}
- init=${init:=100}
- $cmd $lb
- lb_val=$?
- if [ -z "$ub" ]; then
- # find the upper bound
- ub=$(($init + $lb))
- true
- while [ $? -eq $lb_val ]; do
- ub=$(($ub * 10))
- #ub=`expr $ub \* 10`
- $cmd $ub
- done
- fi
- echo command: $cmd
- true
- while [ `expr $ub - $lb` -gt 1 ]; do
- try=$(($lb + ( $ub - $lb ) / 2))
- $cmd $try
- if [ $? -eq $lb_val ]; then
- lb=$try
- else
- ub=$try
- fi
- done
- echo lbound: $lb
- echo ubound: $ub
- =====================================
- */
- /* Debug counter definitions. */
- DEBUG_COUNTER (auto_inc_dec)
- DEBUG_COUNTER (ccp)
- DEBUG_COUNTER (cfg_cleanup)
- DEBUG_COUNTER (cse2_move2add)
- DEBUG_COUNTER (cprop)
- DEBUG_COUNTER (dce)
- DEBUG_COUNTER (dce_fast)
- DEBUG_COUNTER (dce_ud)
- DEBUG_COUNTER (delete_trivial_dead)
- DEBUG_COUNTER (devirt)
- DEBUG_COUNTER (df_byte_scan)
- DEBUG_COUNTER (dse)
- DEBUG_COUNTER (dse1)
- DEBUG_COUNTER (dse2)
- DEBUG_COUNTER (gcse2_delete)
- DEBUG_COUNTER (global_alloc_at_func)
- DEBUG_COUNTER (global_alloc_at_reg)
- DEBUG_COUNTER (graphite_scop)
- DEBUG_COUNTER (hoist)
- DEBUG_COUNTER (hoist_insn)
- DEBUG_COUNTER (ia64_sched2)
- DEBUG_COUNTER (if_conversion)
- DEBUG_COUNTER (if_conversion_tree)
- DEBUG_COUNTER (if_after_combine)
- DEBUG_COUNTER (if_after_reload)
- DEBUG_COUNTER (local_alloc_for_sched)
- DEBUG_COUNTER (postreload_cse)
- DEBUG_COUNTER (pre)
- DEBUG_COUNTER (pre_insn)
- DEBUG_COUNTER (treepre_insert)
- DEBUG_COUNTER (tree_sra)
- DEBUG_COUNTER (eipa_sra)
- DEBUG_COUNTER (vect_loop)
- DEBUG_COUNTER (vect_slp)
- DEBUG_COUNTER (sched2_func)
- DEBUG_COUNTER (sched_block)
- DEBUG_COUNTER (sched_func)
- DEBUG_COUNTER (sched_insn)
- DEBUG_COUNTER (sched_breakdep)
- DEBUG_COUNTER (sched_region)
- DEBUG_COUNTER (sel_sched_cnt)
- DEBUG_COUNTER (sel_sched_region_cnt)
- DEBUG_COUNTER (sel_sched_insn_cnt)
- DEBUG_COUNTER (sms_sched_loop)
- DEBUG_COUNTER (store_motion)
- DEBUG_COUNTER (split_for_sched2)
- DEBUG_COUNTER (tail_call)
- DEBUG_COUNTER (ira_move)
- DEBUG_COUNTER (registered_jump_thread)
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