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   1 /*-------------------------------------------------------------------------
   2
   3    pcodeflow.c - post code generation flow analysis
   4
   5    Written By -  Scott Dattalo scott@dattalo.com
   6
   7    This program is free software; you can redistribute it and/or modify it
   8    under the terms of the GNU General Public License as published by the
   9    Free Software Foundation; either version 2, or (at your option) any
  10    later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  20
  21 -------------------------------------------------------------------------*/
  22 /*
  23   pcodeflow.c
  24
  25   The purpose of the code in this file is to analyze the flow of the
  26   pCode.
  27
  28 */
  29
  30 #include <stdio.h>
  31
  32 #include "common.h"   // Include everything in the SDCC src directory
  33 #include "newalloc.h"
  34 #include "ralloc.h"
  35 #include "device.h"
  36 #include "pcode.h"
  37 #include "pcoderegs.h"
  38 #include "pcodeflow.h"
  39
  40 #if 0
  41
  42 /*
  43    In the section that follows, an exhaustive flow "tree" is built.
  44    It's not a tree that's really built, but instead every possible
  45    flow path is constructed.
  46
  47    This is really overkill...
  48 */
  49
  50 static set *FlowTree=NULL;
  51
  52 void dbg_dumpFlowTree(set *FlowTree)
  53 {
  54   set *segment;
  55   pCodeFlow *pcflow;
  56
  57   fprintf(stderr,"Flow Tree: \n");
  58
  59   for(segment = setFirstItem(FlowTree); segment; segment=setNextItem(FlowTree)) {
  60
  61     fprintf(stderr,"Segment:\n");
  62
  63     for(pcflow=PCFL(setFirstItem(segment)); pcflow; pcflow=PCFL(setNextItem(segment))) {
  64       fprintf(stderr, "  0x%03x",pcflow->pc.seq);
  65     }
  66     fprintf(stderr,"\n");
  67   }
  68
  69 }
  70
  71
  72
  73
  74 /*-----------------------------------------------------------------*
  75  * void BuildFlowSegment(set *segment, pCodeFlow *pcflow)
  76  *-----------------------------------------------------------------*/
  77 void BuildFlowSegment(set *segment, pCodeFlow *pcflow)
  78 {
  79
  80   int nNextFlow=0;
  81   pCodeFlowLink *pcflowLink=NULL;
  82
  83   /* Add this flow to the set if it's not in there already */
  84   if(isinSet(segment, pcflow)) {
  85     addSetHead(&FlowTree, segment);
  86     return;
  87   }
  88
  89   addSetHead(&segment, pcflow);
  90
  91   /* Continue to add contiguous flows */
  92
  93   while( pcflow->to && ((nNextFlow = elementsInSet(pcflow->to)) == 1)) {
  94     pcflowLink = (pCodeFlowLink *)(setFirstItem(pcflow->to));
  95     pcflow = pcflowLink->pcflow;
  96
  97     if(isinSet(segment, pcflow)) {
  98       addSetIfnotP(&FlowTree, segment);
  99       return;
 100     }
 101
 102     addSetIfnotP(&segment, pcflow);
 103
 104   }
 105
 106   /* Branch: for each branch, duplicate the set and recursively call */
 107   if(pcflow->to && nNextFlow>=2) {
 108     pCodeFlow *pcflow_to;
 109
 110     set *branch_segment=NULL;
 111
 112     pcflowLink = (pCodeFlowLink *)(setFirstItem(pcflow->to));
 113     pcflow_to = pcflowLink->pcflow;
 114
 115     addSetIfnotP(&segment, pcflow);
 116
 117     pcflowLink = (pCodeFlowLink *)(setNextItem(pcflow->to));
 118
 119     while(pcflowLink) {
 120
 121       branch_segment = setFromSet(segment);
 122       BuildFlowSegment(setFromSet(segment),pcflowLink->pcflow);
 123       pcflowLink = (pCodeFlowLink *)(setNextItem(pcflow->to));
 124     }
 125
 126     /* add the first branch to this segment */
 127     BuildFlowSegment(segment,pcflow_to);
 128
 129   }
 130
 131   addSetIfnotP(&FlowTree, segment);
 132
 133   /* done */
 134 }
 135
 136 /*-----------------------------------------------------------------*
 137  * void BuildFlowTree(pBlock *pb)
 138  *-----------------------------------------------------------------*/
 139 void BuildFlowTree(pBlock *pb)
 140 {
 141   pCodeFlow *pcflow;
 142   set *segment;
 143
 144   FlowTree = newSet();
 145
 146   /* Start with the first flow object of this pBlock */
 147
 148   pcflow = PCFL(findNextpCode(pb->pcHead, PC_FLOW));
 149
 150   segment = newSet();
 151   BuildFlowSegment(segment, pcflow);
 152
 153   pb->FlowTree = FlowTree;
 154
 155   dbg_dumpFlowTree(FlowTree);
 156 }
 157 #endif
 158
 159 void LinkFlow(pBlock *pb)
 160 {
 161   pCode *pc=NULL;
 162   pCode *pcflow;
 163   pCode *pct;
 164
 165   //fprintf(stderr,"linkflow \n");
 166
 167   for( pcflow = findNextpCode(pb->pcHead, PC_FLOW);
 168        pcflow != NULL;
 169        pcflow = findNextpCode(pcflow->next, PC_FLOW) ) {
 170
 171     if(!isPCFL(pcflow))
 172       fprintf(stderr, "LinkFlow - pcflow is not a flow object ");
 173
 174
 175   }
 176 }