Beispiel #1
0
    Shape *MakeLoop(BlockSet &Blocks, BlockSet& Entries, BlockSet &NextEntries) {
      // Find the inner blocks in this loop. Proceed backwards from the entries until
      // you reach a seen block, collecting as you go.
      BlockSet InnerBlocks;
      BlockSet Queue = Entries;
      while (Queue.size() > 0) {
        Block *Curr = *(Queue.begin());
        Queue.erase(Queue.begin());
        if (InnerBlocks.find(Curr) == InnerBlocks.end()) {
          // This element is new, mark it as inner and remove from outer
          InnerBlocks.insert(Curr);
          Blocks.erase(Curr);
          // Add the elements prior to it
          for (BlockBranchMap::iterator iter = Curr->BranchesIn.begin(); iter != Curr->BranchesIn.end(); iter++) {
            Queue.insert(iter->first);
          }
        }
      }
      assert(InnerBlocks.size() > 0);

      for (BlockSet::iterator iter = InnerBlocks.begin(); iter != InnerBlocks.end(); iter++) {
        Block *Curr = *iter;
        for (BlockBranchMap::iterator iter = Curr->BranchesOut.begin(); iter != Curr->BranchesOut.end(); iter++) {
          Block *Possible = iter->first;
          if (InnerBlocks.find(Possible) == InnerBlocks.end() &&
              NextEntries.find(Possible) == NextEntries.find(Possible)) {
            NextEntries.insert(Possible);
          }
        }
      }

      PrintDebug("creating loop block:\n");
      DebugDump(InnerBlocks, "  inner blocks:");
      DebugDump(Entries, "  inner entries:");
      DebugDump(Blocks, "  outer blocks:");
      DebugDump(NextEntries, "  outer entries:");

      // TODO: Optionally hoist additional blocks into the loop

      LoopShape *Loop = new LoopShape();
      Notice(Loop);

      // Solipsize the loop, replacing with break/continue and marking branches as Processed (will not affect later calculations)
      // A. Branches to the loop entries become a continue to this shape
      for (BlockSet::iterator iter = Entries.begin(); iter != Entries.end(); iter++) {
        Solipsize(*iter, Branch::Continue, Loop, InnerBlocks);
      }
      // B. Branches to outside the loop (a next entry) become breaks on this shape
      for (BlockSet::iterator iter = NextEntries.begin(); iter != NextEntries.end(); iter++) {
        Solipsize(*iter, Branch::Break, Loop, InnerBlocks);
      }
      // Finish up
      Shape *Inner = Process(InnerBlocks, Entries, NULL);
      Loop->Inner = Inner;
      return Loop;
    }
Beispiel #2
0
 void FindLive(Block *Root) {
   BlockList ToInvestigate;
   ToInvestigate.push_back(Root);
   while (ToInvestigate.size() > 0) {
     Block *Curr = ToInvestigate.front();
     ToInvestigate.pop_front();
     if (Live.find(Curr) != Live.end()) continue;
     Live.insert(Curr);
     for (BlockBranchMap::iterator iter = Curr->BranchesOut.begin(); iter != Curr->BranchesOut.end(); iter++) {
       ToInvestigate.push_back(iter->first);
     }
   }
 }
Beispiel #3
0
 // Converts/processes all branchings to a specific target
 void Solipsize(Block *Target, Branch::FlowType Type, Shape *Ancestor, BlockSet &From) {
   PrintDebug("Solipsizing branches into %d\n", Target->Id);
   DebugDump(From, "  relevant to solipsize: ");
   for (BlockSet::iterator iter = Target->BranchesIn.begin(); iter != Target->BranchesIn.end();) {
     Block *Prior = *iter;
     if (From.find(Prior) == From.end()) {
       iter++;
       continue;
     }
     Branch *PriorOut = Prior->BranchesOut[Target];
     PriorOut->Ancestor = Ancestor;
     PriorOut->Type = Type;
     if (MultipleShape *Multiple = Shape::IsMultiple(Ancestor)) {
       Multiple->NeedLoop++; // We are breaking out of this Multiple, so need a loop
     }
     iter++; // carefully increment iter before erasing
     Target->BranchesIn.erase(Prior);
     Target->ProcessedBranchesIn.insert(Prior);
     Prior->BranchesOut.erase(Target);
     Prior->ProcessedBranchesOut[Target] = PriorOut;
     PrintDebug("  eliminated branch from %d\n", Prior->Id);
   }
 }