87 lines
3.2 KiB
Modula-2
87 lines
3.2 KiB
Modula-2
/* This file contains the list of the debug counter for GCC.
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Copyright (C) 2006, 2007 Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 2, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING. If not, write to the Free
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Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301, USA. */
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/* A debug counter provides you a way to count an event
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and return false after the counter has exceeded the threshold
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specified by the option.
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What is it used for ?
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This is primarily used to speed up the search for the bad transformation
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an optimization pass does. By doing a binary search on N,
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you can quickly narrow down to one transformation
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which is bad, or which triggers the bad behavior downstream
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(usually in the form of the badly generated code).
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How does it work ?
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Every time dbg_cnt(named-counter) is called,
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the counter is incremented for the named-counter.
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And the incremented value is compared against the threshold (limit)
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specified by the option.
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dbg_cnt () returns true if it is at or below threshold, and false if above.
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How to add a new one ?
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To add a new counter, simply add an entry below with some descriptive name,
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and add call(s) to dbg_cnt(your-counter-name) in appropriate places.
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Usually, you want to control at the finest granularity
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any particular transformation can happen.
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e.g. for each instruction in a dead code elimination,
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or for each copy instruction in register coalescing,
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or constant-propagation for each insn,
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or a block straightening, etc.
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See dce.c for an example. With the dbg_cnt () call in dce.c,
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now a developer can use -fdbg-cnt=dce:N
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to stop doing the dead code elimination after N times.
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How to use it ?
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By default, all limits are UINT_MAX.
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Since debug count is unsigned int, <= UINT_MAX returns true always.
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i.e. dbg_cnt() returns true always regardless of the counter value
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(although it still counts the event).
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Use -fdbg-cnt=counter1:N,counter2:M,...
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which sets the limit for counter1 to N, and the limit for counter2 to M, etc.
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e.g. setting a limit to zero will make dbg_cnt () return false *always*.
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*/
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/* Debug counter definitions. */
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DEBUG_COUNTER (auto_inc_dec)
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DEBUG_COUNTER (cse2_move2add)
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DEBUG_COUNTER (dce)
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DEBUG_COUNTER (delete_trivial_dead)
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DEBUG_COUNTER (dse)
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DEBUG_COUNTER (gcse2_delete)
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DEBUG_COUNTER (ia64_sched2)
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DEBUG_COUNTER (local_alloc_for_sched)
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DEBUG_COUNTER (postreload_cse)
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DEBUG_COUNTER (pre_insn)
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DEBUG_COUNTER (sched2_func)
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DEBUG_COUNTER (sched_block)
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DEBUG_COUNTER (sched_func)
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DEBUG_COUNTER (sched_insn)
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DEBUG_COUNTER (sched_region)
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DEBUG_COUNTER (split_for_sched2)
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DEBUG_COUNTER (tail_call)
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DEBUG_COUNTER (global_alloc_at_func)
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DEBUG_COUNTER (global_alloc_at_reg)
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