osprey/be/cg/freq.h

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/*

  Copyright (C) 2000, 2001 Silicon Graphics, Inc.  All Rights Reserved.

  This program is free software; you can redistribute it and/or modify it
  under the terms of version 2 of the GNU General Public License as
  published by the Free Software Foundation.

  This program is distributed in the hope that it would be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  

  Further, this software is distributed without any warranty that it is
  free of the rightful claim of any third person regarding infringement 
  or the like.  Any license provided herein, whether implied or 
  otherwise, applies only to this software file.  Patent licenses, if 
  any, provided herein do not apply to combinations of this program with 
  other software, or any other product whatsoever.  

  You should have received a copy of the GNU General Public License along
  with this program; if not, write the Free Software Foundation, Inc., 59
  Temple Place - Suite 330, Boston MA 02111-1307, USA.

  Contact information:  Silicon Graphics, Inc., 1600 Amphitheatre Pky,
  Mountain View, CA 94043, or:

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*/


/* ====================================================================
 * ====================================================================
 *
 * Module: freq.h
 * $Revision: 1.2 $
 * $Date: 02/11/07 23:41:24-00:00 $
 * $Author: fchow@keyresearch.com $
 * $Source: /scratch/mee/2.4-65/kpro64-pending/be/cg/SCCS/s.freq.h $
 *
 * Description:
 *
 * Utilities for determining execution frequencies of BBs and edges.
 *
 * Utilities:
 *
 *    void FREQ_Compute_BB_Frequencies(void)
 *  Determine the block and edge frequency for all BBs in the control flow 
 *  graph. This is done using several heuristics to predict the direction
 *  of conditional branches and/or feedback if available. This routine
 *  also sets the BB_freq field of each basic block.
 *
 *    void FREQ_Incorporate_Feedback(cosnt WN* entry)
 *  Incorporate feedback (from the WHIRL) into the CG CFG; entry is the 
 *  entry whirl node of the tree
 *
 *    void FREQ_Print_BB_Note(BB *bb, FILE *file)
 *  Print a note to 'file' which indicates the block and successor
 *  edge frequencies for 'bb'.
 *
 *    void FREQ_Region_Initialize(void)
 *  Must be called at the start of processing for each region.
 *
 *    BOOL FREQ_Frequencies_Computed(void)
 *  Returns TRUE if block and edge frequencies have been computed;
 *  i.e. FREQ_Compute_BB_Frequencies was called and -CG:enable_freq
 *  was TRUE.
 *
 *    BOOL WN_Is_Pointer(WN *wn)
 *  Returns TRUE if whirl node 'wn' is a pointer.
 *
 *    BOOL FREQ_Match(float f1, float f2)
 *  Return TRUE if BB_freqs <f1> and <f2> are "close enough" (used in
 *  sanity checks of frequency info).
 *
 *    BOOL FREQ_Check_Consistency(const char *caller)
 *      Perform a consistency check over the BBs in the region.
 *      DevWarn if a problem is found. <caller> is an ascii string
 *      to identify the caller in error messages.  Return TRUE iff
 *      check detects no errors.
 *
 *    BB_SET *FREQ_Find_Never_BBs(MEM_POOL *pool)
 *  Return the set of BBs that can be inferred are never executed
 *  as a result of NEVER frequency hint pragmas. The returned set
 *      is allocated from <pool>. If there are no NEVER BBs, then
 *      NULL is returned instead of an empty set.
 *
 *    void FREQ_View_CFG(const char *status)
 *  Use DaVinci to view a feedback/frequency annotated CFG.
 *  <status> is an informational string used to label the graph.
 *
 *    BOOL FREQ_Verify(const char *caller)
 *      Prints the block frequencies and edge probabilites of the
 *      current region into the trace file.  Also prints a "FAIL"
 *      message to the trace file if a consistency problem is found.
 *      <caller> is an ascii string to identify the caller.
 *      Return TRUE iff no errors are detected.
 *
 * ====================================================================
 * ====================================================================
 */

#ifndef FREQ_INCLUDED
#define FREQ_INCLUDED

#include "bb_set.h"

extern void FREQ_Compute_BB_Frequencies(void);

extern void FREQ_Print_BB_Note(
  BB *bb,
  FILE *file
);

extern void FREQ_Region_Initialize(void);

inline BOOL FREQ_Frequencies_Computed(void)
{
  extern BOOL FREQ_freqs_computed;
  return FREQ_freqs_computed;
}

extern BOOL WN_Is_Pointer(WN *wn);

inline BOOL FREQ_Match(float f1, float f2)
{
  float ratio;

  if (f1 == f2) return TRUE;

  /* Tolerance is 0.1% of (f1+f2).  When (f1+f2) is zero, we'll
   * always return FALSE, but that's desirable since negative
   * freqs don't make sense.
   */
  ratio = (f1-f2)/(f1+f2);
  return ratio <= 0.001 && ratio >= -0.001;
}

extern BOOL FREQ_Check_Consistency(const char *caller);

extern BB_SET *FREQ_Find_Never_BBs(MEM_POOL *pool);

extern void FREQ_Incorporate_Feedback(const WN* entry);

extern void FREQ_View_CFG(const char *status);

extern BOOL FREQ_Verify(const char *caller);

#endif /* FREQ_INCLUDED */

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